Quantifying the relationship between extreme air pollution events and extreme weather events

NASA Astrophysics Data System (ADS)

Zhang, Henian; Wang, Yuhang; Park, Tae-Won; Deng, Yi

2017-05-01

Extreme weather events can strongly affect surface air quality, which has become a major environmental factor to affect human health. Here, we examined the relationship between extreme ozone and PM2.5 (particular matter with an aerodynamic diameter less than 2.5 μm) events and the representative meteorological parameters such as daily maximum temperature (Tmax), minimum relative humidity (RHmin), and minimum wind speed (Vmin), using the location-specific 95th or 5th percentile threshold derived from historical reanalysis data (30 years for ozone and 10 years for PM2.5). We found that ozone and PM2.5 extremes were decreasing over the years, reflecting EPA's tightened standards and effort on reducing the corresponding precursor's emissions. Annual ozone and PM2.5 extreme days were highly correlated with Tmax and RHmin, especially in the eastern U.S. They were positively (negatively) correlated with Vmin in urban (rural and suburban) stations. The overlapping ratios of ozone extreme days with Tmax were fairly constant, about 32%, and tended to be high in fall and low in winter. Ozone extreme days were most sensitive to Tmax, then RHmin, and least sensitive to Vmin. The majority of ozone extremes occurred when Tmax was between 300 K and 320 K, RHmin was less than 40%, and Vmin was less than 3 m/s. The number of annual extreme PM2.5 days was highly positively correlated with the extreme RHmin/Tmax days, with correlation coefficient between PM2.5/RHmin highest in urban and suburban regions and the correlation coefficient between PM2.5/Tmax highest in rural area. Tmax has more impact on PM2.5 extreme over the eastern U.S. Extreme PM2.5 days were more likely to occur at low RH conditions in the central and southeastern U.S., especially during spring time, and at high RH conditions in the northern U.S. and the Great Plains. Most extreme PM2.5 events occurred when Tmax was between 300 K and 320 K and RHmin was between 10% and 50%. Extreme PM2.5 days usually occurred when Vmin was under 2 m/s. However, during spring season in the Southeast and fall season in Northwest, high winds were found to accompany extreme PM2.5 days, likely reflecting the impact of fire emissions.

Observed warming over northern South America has an anthropogenic origin

NASA Astrophysics Data System (ADS)

Barkhordarian, Armineh; von Storch, Hans; Zorita, Eduardo; Loikith, Paul C.; Mechoso, Carlos R.

2017-10-01

We investigate whether the recently observed trends in daily maximum and minimum near-surface air temperature (Tmax and Tmin, respectively) over South America (SA) are consistent with the simulated response of Tmin and Tmax to anthropogenic forcing. Results indicate that the recently observed warming in the dry seasons is well beyond the range of natural (internal) variability. In the wet season the natural modes of variability explain a substantial portion of Tmin and Tmax variability. We demonstrate that the large-scale component of greenhouse gas (GHG) forcing is detectable in dry-seasonal warming. However, none of the global and regional climate change projections reproduce the observed warming of up to 0.6 K/Decade in Tmax in 1983-2012 over northern SA during the austral spring (SON). Thus, besides the global manifestation of GHG forcing, other external drivers have an imprint. Using aerosols-only forcing simulations, our results provide evidence that anthropogenic aerosols also have a detectable influence in SON and that the indirect effect of aerosols on cloud's lifetime is more compatible with the observed record. In addition, there is an increasing trend in the observed incoming solar radiation over northern SA in SON, which is larger than expected from natural (internal) variability alone. We further show that in the dry seasons the spread of projected trends based on the RCP4.5 scenario derived from 30 CMIP5 models encompasses the observed area-averaged trends in Tmin and Tmax. This may imply that the observed excessive warming in the dry seasons serve as an illustration of plausible future expected change in the region.

Increasing synchrony of high temperature and low flow in western North American streams: double trouble for coldwater biota?

USGS Publications Warehouse

Arismendi, Ivan; Safeeq, Mohammad; Johnson, Sherri L.; Dunham, Jason B.; Haggerty, Roy

2013-01-01

Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (Tmax_w) and stream flow minima (Qmin) can create periods of stress for aquatic organisms. In mountainous areas, such as western North America, recent shifts toward an earlier spring peak flow and decreases in low flow during summer/fall have been reported. We hypothesized that an earlier peak flow could be shifting the timing of low flow and leading to a decrease in the interval between Tmax_w and Qmin. We also examined if years with extreme low Qmin were associated with years of extreme high Tmax_w. We tested these hypotheses using long32 term data from 22 minimally human-influenced streams for the period 1950-2010. We found trends toward a shorter time lag between Tmax_w and Qmin over time and a strong negative association between their magnitudes. Our findings show that aquatic biota may be increasingly experiencing narrower time windows to recover or adapt between these extreme events of low flow and high temperature. This study highlights the importance of evaluating multiple environmental drivers to better gauge the effects of the recent climate variability in freshwaters.

Impact of increasing heat waves on U.S. ozone episodes in the 2050s: Results from a multimodel analysis using extreme value theory

NASA Astrophysics Data System (ADS)

Shen, L.; Mickley, L. J.; Gilleland, E.

2016-04-01

We develop a statistical model using extreme value theory to estimate the 2000-2050 changes in ozone episodes across the United States. We model the relationships between daily maximum temperature (Tmax) and maximum daily 8 h average (MDA8) ozone in May-September over 2003-2012 using a Point Process (PP) model. At ~20% of the sites, a marked decrease in the ozone-temperature slope occurs at high temperatures, defined as ozone suppression. The PP model sometimes fails to capture ozone-Tmax relationships, so we refit the ozone-Tmax slope using logistic regression and a generalized Pareto distribution model. We then apply the resulting hybrid-extreme value theory model to projections of Tmax from an ensemble of downscaled climate models. Assuming constant anthropogenic emissions at the present level, we find an average increase of 2.3 d a-1 in ozone episodes (>75 ppbv) across the United States by the 2050s, with a change of +3-9 d a-1 at many sites.

Temperatures in Excess of Critical Thresholds Threaten Nestling Growth and Survival in A Rapidly-Warming Arid Savanna: A Study of Common Fiscals

PubMed Central

Cunningham, Susan J.; Martin, Rowan O.; Hojem, Carryn L.

2013-01-01

Frequency, duration, and intensity of hot-weather events are all predicted to increase with climate warming. Despite this, mechanisms by which temperature increases affect individual fitness and drive population-level changes are poorly understood. We investigated the link between daily maximum air temperature (tmax) and breeding success of Kalahari common fiscals (Lanius collaris) in terms of the daily effect on nestling body-mass gain, and the cumulative effect on size and age of fledglings. High tmax reduced mass gain of younger, but not older nestlings and average nestling-period tmax did not affect fledgling size. Instead, the frequency with which tmax exceeded critical thresholds (tcrits) significantly reduced fledging body mass (tcrit = 33°C) and tarsus length (tcrit = 37°C), as well as delaying fledging (tcrit = 35°C). Nest failure risk was 4.2% per day therefore delays reduced fledging probability. Smaller size at fledging often correlates with reduced lifetime fitness and might also underlie documented adult body-size reductions in desert birds in relation to climate warming. Temperature thresholds above which organisms incur fitness costs are probably common, as physiological responses to temperature are non-linear. Understanding the shape of the relationship between temperature and fitness has implications for our ability to predict species’ responses to climate change. PMID:24040296

Recrystallization and grain growth behavior of rolled tungsten under VDE-like short pulse high heat flux loads

NASA Astrophysics Data System (ADS)

Yuan, Y.; Greuner, H.; Böswirth, B.; Krieger, K.; Luo, G.-N.; Xu, H. Y.; Fu, B. Q.; Li, M.; Liu, W.

2013-02-01

Short pulse heat loads expected for vertical displacement events (VDEs) in ITER were applied in the high heat flux (HHF) test facility GLADIS at IPP-Garching onto samples of rolled W. Pulsed neutral beams with the central heat flux of 23 MW/m2 were applied for 0.5, 1.0 and 1.5 s, respectively. Rapid recrystallization of the adiabatically loaded 3 mm thick samples was observed when the pulse duration was up to 1.0 s. Grains grew markedly following recrystallization with increasing pulse length. The recrystallization temperature and temperature dependence of the recrystallized grain size were also investigated. The results showed that the recrystallization temperature of the W grade was around 2480 °C under the applied heat loading condition, which was nearly 1150 °C higher than the conventional recrystallization temperature, and the grains were much finer. A linear relationship between the logarithm of average grain size (ln d) and the inverse of maximum surface temperature (1/Tmax) was found and accordingly the activation energy for grain growth in temperature evolution up to Tmax in 1.5 s of the short pulse HHF load was deduced to be 4.1 eV. This provided an effective clue to predict the structure evolution under short pulse HHF loads.

Daily air temperature interpolated at high spatial resolution over a large mountainous region

USGS Publications Warehouse

Dodson, R.; Marks, D.

1997-01-01

Two methods are investigated for interpolating daily minimum and maximum air temperatures (Tmin and Tmax) at a 1 km spatial resolution over a large mountainous region (830 000 km2) in the U.S. Pacific Northwest. The methods were selected because of their ability to (1) account for the effect of elevation on temperature and (2) efficiently handle large volumes of data. The first method, the neutral stability algorithm (NSA), used the hydrostatic and potential temperature equations to convert measured temperatures and elevations to sea-level potential temperatures. The potential temperatures were spatially interpolated using an inverse-squared-distance algorithm and then mapped to the elevation surface of a digital elevation model (DEM). The second method, linear lapse rate adjustment (LLRA), involved the same basic procedure as the NSA, but used a constant linear lapse rate instead of the potential temperature equation. Cross-validation analyses were performed using the NSA and LLRA methods to interpolate Tmin and Tmax each day for the 1990 water year, and the methods were evaluated based on mean annual interpolation error (IE). The NSA method showed considerable bias for sites associated with vertical extrapolation. A correction based on climate station/grid cell elevation differences was developed and found to successfully remove the bias. The LLRA method was tested using 3 lapse rates, none of which produced a serious extrapolation bias. The bias-adjusted NSA and the 3 LLRA methods produced almost identical levels of accuracy (mean absolute errors between 1.2 and 1.3??C), and produced very similar temperature surfaces based on image difference statistics. In terms of accuracy, speed, and ease of implementation, LLRA was chosen as the best of the methods tested.

Strong impacts of daily minimum temperature on the green-up date and summer greenness of the Tibetan Plateau.

PubMed

Shen, Miaogen; Piao, Shilong; Chen, Xiaoqiu; An, Shuai; Fu, Yongshuo H; Wang, Shiping; Cong, Nan; Janssens, Ivan A

2016-09-01

Understanding vegetation responses to climate change on the Tibetan Plateau (TP) helps in elucidating the land-atmosphere energy exchange, which affects air mass movement over and around the TP. Although the TP is one of the world's most sensitive regions in terms of climatic warming, little is known about how the vegetation responds. Here, we focus on how spring phenology and summertime greenness respond to the asymmetric warming, that is, stronger warming during nighttime than during daytime. Using both in situ and satellite observations, we found that vegetation green-up date showed a stronger negative partial correlation with daily minimum temperature (Tmin ) than with maximum temperature (Tmax ) before the growing season ('preseason' henceforth). Summer vegetation greenness was strongly positively correlated with summer Tmin , but negatively with Tmax . A 1-K increase in preseason Tmin advanced green-up date by 4 days (P < 0.05) and in summer enhanced greenness by 3.6% relative to the mean greenness during 2000-2004 (P < 0.01). In contrast, increases in preseason Tmax did not advance green-up date (P > 0.10) and higher summer Tmax even reduced greenness by 2.6% K(-1) (P < 0.05). The stimulating effects of increasing Tmin were likely caused by reduced low temperature constraints, and the apparent negative effects of higher Tmax on greenness were probably due to the accompanying decline in water availability. The dominant enhancing effect of nighttime warming indicates that climatic warming will probably have stronger impact on TP ecosystems than on apparently similar Arctic ecosystems where vegetation is controlled mainly by Tmax . Our results are crucial for future improvements of dynamic vegetation models embedded in the Earth System Models which are being used to describe the behavior of the Asian monsoon. The results are significant because the state of the vegetation on the TP plays an important role in steering the monsoon. © 2016 John Wiley & Sons Ltd.

Heat waves in Senegal : detection, characterization and associated processes.

NASA Astrophysics Data System (ADS)

Gnacoussa Sambou, Marie Jeanne; Janicot, Serge; Badiane, Daouda; Pohl, Benjamin; Dieng, Abdou L.; Gaye, Amadou T.

2017-04-01

Atmospheric configuration and synoptic evolution of patterns associated with Senegalese heat wave (HW) are examined on the period 1979-2014 using the Global Surface Summary of the Day (GSOD) observational database and ERA-Interim reanalysis. Since there is no objective and uniform definition of HW events, threshold methods based on atmospheric variables as daily maximum (Tmax) / minimum (Tmin) temperatures and daily mean apparent temperature (AT) are used to define HW threshold detection. Each criterion is related to a specific category of HW events: Tmax (warm day events), Tmin (warm night events) and AT (combining temperature and moisture). These definitions are used in order to characterize as well as possible the warm events over the Senegalese regions (oceanic versus continental region). Statistics on time evolution and spatial distribution of warm events are carried out over the 2 seasons of maximum temperature (March-May and October-November). For each season, a composite of HW events, as well as the most extended event over Senegal (as a case study) are analyzed using usual atmospheric fields (sea level pressure, geopotential height, total column water content, wind components, 2m temperature). This study is part of the project ACASIS (https://acasis.locean-ipsl.upmc.fr/doku.php) on heat waves occurrences over the Sahel and their impact on health. Keywords: heat wave, Senegal, ACASIS.

Statistical downscaling of mean temperature, maximum temperature, and minimum temperature on the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Jiang, L.

2017-12-01

Climate change is considered to be one of the greatest environmental threats. Global climate models (GCMs) are the primary tool used for studying climate change. However, GCMs are limited because of their coarse spatial resolution and inability to resolve important sub-grid scale features such as terrain and clouds. Statistical downscaling methods can be used to downscale large-scale variables to local-scale. In this study, we assess the applicability of the Statistical Downscaling Model (SDSM) in downscaling the outputs from Beijing Normal University Earth System Model (BNU-ESM). The study focus on the the Loess Plateau, China, and the variables for downscaling include daily mean temperature (TMEAN), maximum temperature (TMAX) and minimum temperature (TMIN). The results show that SDSM performs well for these three climatic variables on the Loess Plateau. After downscaling, the root mean square errors for TMEAN, TMAX, TMIN for BNU-ESM were reduced by 70.9%, 75.1%, and 67.2%, respectively. All the rates of change in TMEAN, TMAX and TMIN during the 21st century decreased after SDSM downscaling. We also show that SDSM can effectively reduce uncertainty, compared with the raw model outputs. TMEAN uncertainty was reduced by 27.1%, 26.8%, and 16.3% for the future scenarios of RCP 2.6, RCP 4.5 and RCP 8.5, respectively. The corresponding reductions in uncertainty were 23.6%, 30.7%, and 18.7% for TMAX; 37.6%, 31.8%, and 23.2% for TMIN.

Sympathicotomy for Palmar Hyperhidrosis: The Association between Intraoperative Palm Temperature Change and the Curative Effect

PubMed Central

Liu, Yanguo; Li, Hao; Zheng, Xia; Li, Xiao; Li, Jianfeng; Jiang, Guanchao

2015-01-01

Purpose: To investigate the association between intraoperative palm temperature change and the curative effect of sympathicotomy. Methods: 49 patients with palmar hyperhidrosis were treated with bilateral endoscopic sympathicotomy. Ipsilateral palm temperature was monitored before and at 3–5 min increments after the sympathetic trunk was transected. The maximum temperature elevation (Tmax) was calculated and used to evaluate the effect on postoperative cure rates. Results: Forty-nine patients underwent 98 sympathicotomies. There were 77 T4 sympathicotomies, 15 T4 + T5 sympathicotomies, and six T3 sympathicotomies due to pleural adhesions or neurovascular proximity. The Tmax was ≤1°C in 49 (50.0%), 1–1.5°C in 17 (17.3%), and >1.5°C in 32 (32.7%) palms. Ninety-two palms of 46 patients were followed with complete efficacy, and three patients were lost to follow up. Cure was achieved in 86 palms (93.4%). Of the 71 palms which underwent T4 sympathicotomy, cure was achieved in 67 palms (94.3%). In those palms which did not achieve cure, the Tmax was less than 1°C in each case, while in palms with a Tmax ≤1°C, 32 of 36 (88.9%) were cured. Conclusion: There is an association between intraoperative palmar temperature change and curative effect. However, palmar temperature change cannot be used to predict cure or guide surgical approach. PMID:26041256

Residual stress and damage-induced critical fracture on CO2 laser treated fused silica

NASA Astrophysics Data System (ADS)

Matthews, M. J.; Stolken, J. S.; Vignes, R. M.; Norton, M. A.; Yang, S.; Cooke, J. D.; Guss, G. M.; Adams, J. J.

2009-10-01

Localized damage repair and polishing of silica-based optics using mid- and far-IR CO2 lasers has been shown to be an effective method for increasing optical damage threshold in the UV. However, it is known that CO2 laser heating of silicate surfaces can lead to a level of residual stress capable of causing critical fracture either during or after laser treatment. Sufficient control of the surface temperature as a function of time and position is therefore required to limit this residual stress to an acceptable level to avoid critical fracture. In this work we present the results of 351 nm, 3ns Gaussian damage growth experiments within regions of varying residual stress caused by prior CO2 laser exposures. Thermally stressed regions were non-destructively characterized using polarimetry and confocal Raman microscopy to measure the stress induced birefringence and fictive temperature respectively. For 1~40s square pulse CO2 laser exposures created over 0.5-1.25kW/cm2 with a 1-3mm 1/e2 diameter beam (Tmax~1500-3000K), the critical damage site size leading to fracture increases weakly with peak temperature, but shows a stronger dependence on cooling rate, as predicted by finite element hydrodynamics simulations. Confocal micro-Raman was used to probe structural changes to the glass over different thermal histories and indicated a maximum fictive temperature of 1900K for Tmax>=2000K. The effect of cooling rate on fictive temperature caused by CO2 laser heating are consistent with finite element calculations based on a Tool-Narayanaswamy relaxation model.

How Close Are We to the Temperature Tipping Point of the Biosphere?

NASA Astrophysics Data System (ADS)

Duffy, K. H.

2017-12-01

All biological processes accelerate rapidly with increasing temperature (Tinf); reaching a maximum rate (Tmax), after which they decline. However different biological processes may not be synchronised in their response to increasing temperatures resulting in major dis-equilibria of ecosystem processes. Particularly, the linked processes of photosynthesis and respiration have different curvature that is determined by their inherent sensitivity to temperature. Constraining the difference in temperature curves between photosynthesis and respiration allows us to quantify changes to global carbon metabolism and the land sink of carbon as a whole. During the last century the biosphere has acted as a sink of carbon from the atmosphere partly mitigating accumulation of CO2 derived from burning of fossil fuels Here we ask the following questions: As global temperature increases will photosynthesis and respiration become de-coupled and when? What is Tmax for the land sink, and where is current mean temperature range in regard to this important threshold? At what global and regional temperatures do we expect the biosphere to become a source of carbon to the atmosphere? To address these questions we used the recently released FLUXNET2015 dataset comprised of 212 eddy covariance flux tower sites which concurrently measure land-atmosphere carbon exchange along with micro-meteorological variables. Here, we illustrate our results for Tinf and Tmax of the land sink by biome and for the biosphere as a whole. Our results suggest that recent warming has already pushed us past the inflection point of photosynthesis, and that any additional warming will increase the cumulative annual dose of time spent past Tmax for the land sink. Even under moderate climate projections, we expect to see a slowing of the terrestrial carbon sink by as early as 2040.

The relevance of MRI for patient modeling in head and neck hyperthermia treatment planning: a comparison of CT and CT-MRI based tissue segmentation on simulated temperature.

PubMed

Verhaart, René F; Fortunati, Valerio; Verduijn, Gerda M; van der Lugt, Aad; van Walsum, Theo; Veenland, Jifke F; Paulides, Margarethus M

2014-12-01

In current clinical practice, head and neck (H&N) hyperthermia treatment planning (HTP) is solely based on computed tomography (CT) images. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast over CT. The purpose of the authors' study is to investigate the relevance of using MRI in addition to CT for patient modeling in H&N HTP. CT and MRI scans were acquired for 11 patients in an immobilization mask. Three observers manually segmented on CT, MRI T1 weighted (MRI-T1w), and MRI T2 weighted (MRI-T2w) images the following thermo-sensitive tissues: cerebrum, cerebellum, brainstem, myelum, sclera, lens, vitreous humor, and the optical nerve. For these tissues that are used for patient modeling in H&N HTP, the interobserver variation of manual tissue segmentation in CT and MRI was quantified with the mean surface distance (MSD). Next, the authors compared the impact of CT and CT and MRI based patient models on the predicted temperatures. For each tissue, the modality was selected that led to the lowest observer variation and inserted this in the combined CT and MRI based patient model (CT and MRI), after a deformable image registration. In addition, a patient model with a detailed segmentation of brain tissues (including white matter, gray matter, and cerebrospinal fluid) was created (CT and MRIdb). To quantify the relevance of MRI based segmentation for H&N HTP, the authors compared the predicted maximum temperatures in the segmented tissues (Tmax) and the corresponding specific absorption rate (SAR) of the patient models based on (1) CT, (2) CT and MRI, and (3) CT and MRIdb. In MRI, a similar or reduced interobserver variation was found compared to CT (maximum of median MSD in CT: 0.93 mm, MRI-T1w: 0.72 mm, MRI-T2w: 0.66 mm). Only for the optical nerve the interobserver variation is significantly lower in CT compared to MRI (median MSD in CT: 0.58 mm, MRI-T1w: 1.27 mm, MRI-T2w: 1.40 mm). Patient models based on CT (Tmax: 38.0 °C) and CT and MRI (Tmax: 38.1 °C) result in similar simulated temperatures, while CT and MRIdb (Tmax: 38.5 °C) resulted in significantly higher temperatures. The SAR corresponding to these temperatures did not differ significantly. Although MR imaging reduces the interobserver variation in most tissues, it does not affect simulated local tissue temperatures. However, the improved soft-tissue contrast provided by MRI allows generating a detailed brain segmentation, which has a strong impact on the predicted local temperatures and hence may improve simulation guided hyperthermia.

Climate change in Lagos state, Nigeria: what really changed?

PubMed

Sojobi, Adebayo Olatunbosun; Balogun, Isaac Idowu; Salami, Adebayo Wahab

2015-10-01

Our study revealed periodicities of 2.3 and 2.25 years in wet and dry seasons and periodicities of 2 to 5 years on seasonal and annual timescales. Minimum temperature (Tmin), maximum temperature (Tmax) and evaporation recorded increases of 2.47, 1.37 and 28.37 %, respectively, but a reduction of 19.58 % in rainfall on decadal timescale. Periodicity of 8 to 12 years was also observed in annual Tmax. Cramer's test indicated a warming trend with significant Tmax increase in February, April, July, August, October and November during 2000-2009 on decadal monthly timescale, a significant decline in Summer rainfall but significant Tmax increase in Spring, Autumn and Winter on decadal seasonal timescale. The low correlation of rainfall with temperature parameters and evaporation indicates that advection of moisture into Lagos State seems to be the dominant mechanism controlling rainfall within the State alongside other tropical and extra-tropical factors. In addition, our study revealed that the persistent state of minimum temperature often precedes the arrival and reversal of the phase of maximum temperature. Furthermore, our study also revealed that extreme and high variable rainfalls, which are associated with the increased warming trend, had periodicities of 1 to 3 years with a probability of 86.45 % of occurring every 3 years between April and September. It is recommended that government and private sector should give financial and technical supports to climate researches in order to appropriately inform policy making to improve the adaptive capacity and resilience of Lagos State against climate change impacts and guard against maladaptation.

Statistical downscaling of mean temperature, maximum temperature, and minimum temperature on the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Lin, Jiang; Miao, Chiyuan

2017-04-01

Climate change is considered to be one of the greatest environmental threats. This has urged scientific communities to focus on the hot topic. Global climate models (GCMs) are the primary tool used for studying climate change. However, GCMs are limited because of their coarse spatial resolution and inability to resolve important sub-grid scale features such as terrain and clouds. Statistical downscaling methods can be used to downscale large-scale variables to local-scale. In this study, we assess the applicability of the widely used Statistical Downscaling Model (SDSM) for the Loess Plateau, China. The observed variables included daily mean temperature (TMEAN), maximum temperature (TMAX) and minimum temperature (TMIN) from 1961 to 2005. The and the daily atmospheric data were taken from reanalysis data from 1961 to 2005, and global climate model outputs from Beijing Normal University Earth System Model (BNU-ESM) from 1961 to 2099 and from observations . The results show that SDSM performs well for these three climatic variables on the Loess Plateau. After downscaling, the root mean square errors for TMEAN, TMAX, TMIN for BNU-ESM were reduced by 70.9%, 75.1%, and 67.2%, respectively. All the rates of change in TMEAN, TMAX and TMIN during the 21st century decreased after SDSM downscaling. We also show that SDSM can effectively reduce uncertainty, compared with the raw model outputs. TMEAN uncertainty was reduced by 27.1%, 26.8%, and 16.3% for the future scenarios of RCP 2.6, RCP 4.5 and RCP 8.5, respectively. The corresponding reductions in uncertainty were 23.6%, 30.7%, and 18.7% for TMAX, ; and 37.6%, 31.8%, and 23.2% for TMIN.

Upper thermal tolerance plasticity in tropical amphibian species from contrasting habitats: implications for warming impact prediction.

PubMed

Simon, Monique Nouailhetas; Ribeiro, Pedro Leite; Navas, Carlos Arturo

2015-02-01

Tropical ectothermic species are currently depicted as more vulnerable to increasing temperatures because of the proximity between their upper thermal limits and environmental temperatures. Yet, the acclimatory capacity of thermal limits has rarely been measured in tropical species, even though they are generally predicted to be smaller than in temperate species. We compared critical thermal maximum (CTmax) and warming tolerance (WT: the difference between CTmax and maximum temperature, Tmax), as well as CTmax acclimatory capacity of toad species from the Atlantic forest (AF) and the Brazilian Caatinga (CAA), a semi-arid habitat with high temperatures. Acclimation temperatures represented the mean temperatures of AF and CAA habitats, making estimates of CTmax and WT more ecologically realistic. CAA species mean CTmax was higher compared to AF species in both acclimation treatments. Clutches within species, as well as between AF and CAA species, differed in CTmax plasticity and we discuss the potential biological meaning of these findings. We did not find a trade-off between absolute CTmax and CTmax plasticity, indicating that species can have both high CTmax and high CTmax plasticity. Although CTmax was highly correlated to Tmax, CTmax plasticity was not related to Tmax or Tmax coefficients of variation. CAA species mean WT was lower than for AF species, but still very high for all species, diverging from other studies with tropical species. This might be partially related to over-estimation of vulnerability due to under-appreciation of realistic acclimation treatments in CTmax estimation. Thus, some tropical species might not be as vulnerable to warming as previously predicted if CTmax is considered as a shifting population parameter. Copyright © 2014 Elsevier Ltd. All rights reserved.

Inconsistent Responses of Hot Extremes to Historical Land Use and Cover Change Among the Selected CMIP5 Models

NASA Astrophysics Data System (ADS)

Li, Xing; Chen, Haishan; Wei, Jiangfeng; Hua, Wenjian; Sun, Shanlei; Ma, Hedi; Li, Xiao; Li, Jingping

2018-04-01

Land use and cover change (LUCC) is an important anthropogenic forcing of the climate system. Previous studies have demonstrated that LUCC significantly impacts both mean and extreme temperatures. In this study, we explored the multimodel performance of simulating LUCC-induced asymmetric effects on the different percentiles of maximum temperatures (Tmax) as well as the possible reasons for these effects using results from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Four state-of-art Earth system models (which provide the necessary data) are selected for investigating this issue. In general, all the cases of the model from the Geophysical Fluid Dynamics Laboratory show robust asymmetric responses between the 90th (TX90P) and 10th percentiles (TX10P) of Tmax, mainly due to cropland expansions, especially over India, the Sahel, and some parts of North America. However, weak and insignificant responses are shown for both the TX90P and TX10P in other models. The different changes in the Tmax variability among the models are primarily responsible for the occurrence of asymmetric features. Furthermore, by decomposing the Tmax changes over three typical regions, we analyze the potential causes for the inconsistencies among these models' results and find two crucial processes, that is, the repartitioning of the turbulent heat fluxes and the changes of the diurnal cycle variability due to LUCC. Whether these processes are pronounced determines the occurrence of the asymmetric Tmax responses. Overall, this study provides a critical clue for reducing the uncertainties of the LUCC effects on temperature extremes, which should be evaluated against observations.

The effect of length and starting year on trend analyses of temperatures in Spanish mainland (1951-2010). Seasonal analysis: Winter (II)

NASA Astrophysics Data System (ADS)

Salinas Solé, Celia; Peña Angulo, Dhais; Gonzalez Hidalgo, Jose Carlos; Brunetti, Michele

2017-04-01

In this poster we applied the moving window approach (see Poster I of this collection) to analyze trends of winter and its corresponding months (December, January, February) temperature mean values of maximum (Tmax) and minimum (Tmin) in Spanish mainland to detect the effects of length period and starting year. Monthly series belong to Monthly Temperature dataset of Spanish mainland (MOTEDAS). Database contains in its grid format of 5236 pixels of monthly series (10x10 km). The threshold used in spatial analyses considers 20% of land under significant trend (p<0.05). The most striking results are as follow: • Seasonal trend analyses of Tmax shows that global trend 1951-2010 was positive and significant mostly in central-western areas; from 1970 to 2010 there is less than 20% of land with significant trend. In the case of Tmin no relevant significant period is detected. • Monthly Tmax analyses show that December significant trend changed from positive (>20%) in between 1955-2010 until 1962-2010, to negative from 1976-2010. Meanwhile January does not show relevant period with significant trend; finally Tmax in February shows different periods with positive significant trend (>20% of land) 1951-2010 to 1954-2010 and 1962-2010 to 1968-2010. No significant trend is detected after this data. • Monthly Tmin trend analyses show that except exceptional period, no months present any significant trend. As conclusions, we have detected that for winter and winter-months, Tmax trends are not significant from 1970 across Spanish mainland. In the case of Tmin we conclude that no significant trend have been occurred in any temporal windows analyzed. Results differ from what traditionally has been assumed that the increase of the average annual temperature was due to the increase of trends in the winter season. And these analyses also show that seasonal trend values could hide monthly behavior. So extreme caution should be taken into account when seasonal values are offered.

MOnthly TEmperature DAtabase of Spain 1951-2010: MOTEDAS (2): The Correlation Decay Distance (CDD) and the spatial variability of maximum and minimum monthly temperature in Spain during (1981-2010).

NASA Astrophysics Data System (ADS)

Cortesi, Nicola; Peña-Angulo, Dhais; Simolo, Claudia; Stepanek, Peter; Brunetti, Michele; Gonzalez-Hidalgo, José Carlos

2014-05-01

One of the key point in the develop of the MOTEDAS dataset (see Poster 1 MOTEDAS) in the framework of the HIDROCAES Project (Impactos Hidrológicos del Calentamiento Global en España, Spanish Ministery of Research CGL2011-27574-C02-01) is the reference series for which no generalized metadata exist. In this poster we present an analysis of spatial variability of monthly minimum and maximum temperatures in the conterminous land of Spain (Iberian Peninsula, IP), by using the Correlation Decay Distance function (CDD), with the aim of evaluating, at sub-regional level, the optimal threshold distance between neighbouring stations for producing the set of reference series used in the quality control (see MOTEDAS Poster 1) and the reconstruction (see MOREDAS Poster 3). The CDD analysis for Tmax and Tmin was performed calculating a correlation matrix at monthly scale between 1981-2010 among monthly mean values of maximum (Tmax) and minimum (Tmin) temperature series (with at least 90% of data), free of anomalous data and homogenized (see MOTEDAS Poster 1), obtained from AEMEt archives (National Spanish Meteorological Agency). Monthly anomalies (difference between data and mean 1981-2010) were used to prevent the dominant effect of annual cycle in the CDD annual estimation. For each station, and time scale, the common variance r2 (using the square of Pearson's correlation coefficient) was calculated between all neighbouring temperature series and the relation between r2 and distance was modelled according to the following equation (1): Log (r2ij) = b*°dij (1) being Log(rij2) the common variance between target (i) and neighbouring series (j), dij the distance between them and b the slope of the ordinary least-squares linear regression model applied taking into account only the surrounding stations within a starting radius of 50 km and with a minimum of 5 stations required. Finally, monthly, seasonal and annual CDD values were interpolated using the Ordinary Kriging with a spherical variogram over conterminous land of Spain, and converted on a regular 10 km2 grid (resolution similar to the mean distance between stations) to map the results. In the conterminous land of Spain the distance at which couples of stations have a common variance in temperature (both maximum Tmax, and minimum Tmin) above the selected threshold (50%, r Pearson ~0.70) on average does not exceed 400 km, with relevant spatial and temporal differences. The spatial distribution of the CDD shows a clear coastland-to-inland gradient at annual, seasonal and monthly scale, with highest spatial variability along the coastland areas and lower variability inland. The highest spatial variability coincide particularly with coastland areas surrounded by mountain chains and suggests that the orography is one of the most driving factor causing higher interstation variability. Moreover, there are some differences between the behaviour of Tmax and Tmin, being Tmin spatially more homogeneous than Tmax, but its lower CDD values indicate that night-time temperature is more variable than diurnal one. The results suggest that in general local factors affects the spatial variability of monthly Tmin more than Tmax and then higher network density would be necessary to capture the higher spatial variability highlighted for Tmin respect to Tmax. The results suggest that in general local factors affects the spatial variability of Tmin more than Tmax and then higher network density would be necessary to capture the higher spatial variability highlighted for minimum temperature respect to maximum temperature. A conservative distance for reference series could be evaluated in 200 km, that we propose for continental land of Spain and use in the development of MOTEDAS.

Developing a 1 km resolution daily air temperature dataset for urban and surrounding areas in the conterminous United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xiaoma; Zhou, Yuyu; Asrar, Ghassem R.

High spatiotemporal resolution air temperature (Ta) datasets are increasingly needed for assessing the impact of temperature change on people, ecosystems, and energy system, especially in the urban domains. However, such datasets are not widely available because of the large spatiotemporal heterogeneity of Ta caused by complex biophysical and socioeconomic factors such as built infrastructure and human activities. In this study, we developed a 1-km gridded dataset of daily minimum Ta (Tmin) and maximum Ta (Tmax), and the associated uncertainties, in urban and surrounding areas in the conterminous U.S. for the 2003–2016 period. Daily geographically weighted regression (GWR) models were developedmore » and used to interpolate Ta using 1 km daily land surface temperature and elevation as explanatory variables. The leave-one-out cross-validation approach indicates that our method performs reasonably well, with root mean square errors of 2.1 °C and 1.9 °C, mean absolute errors of 1.5 °C and 1.3 °C, and R 2 of 0.95 and 0.97, for Tmin and Tmax, respectively. The resulting dataset captures reasonably the spatial heterogeneity of Ta in the urban areas, and also captures effectively the urban heat island (UHI) phenomenon that Ta rises with the increase of urban development (i.e., impervious surface area). The new dataset is valuable for studying environmental impacts of urbanization such as UHI and other related effects (e.g., on building energy consumption and human health). The proposed methodology also shows a potential to build a long-term record of Ta worldwide, to fill the data gap that currently exists for studies of urban systems.« less

Collapse of a nanoscopic void triggered by a spherically symmetric traveling sound wave.

PubMed

Hołyst, Robert; Litniewski, Marek; Garstecki, Piotr

2012-05-01

Molecular-dynamics simulations of the Lennard-Jones fluid (up to 10(7) atoms) are used to analyze the collapse of a nanoscopic bubble. The collapse is triggered by a traveling sound wave that forms a shock wave at the interface. The peak temperature T(max) in the focal point of the collapse is approximately ΣR(0)(a), where Σ is the surface density of energy injected at the boundary of the container of radius R(0) and α ≈ 0.4-0.45. For Σ = 1.6 J/m(2) and R(0) = 51 nm, the shock wave velocity, which is proportional to √Σ, reaches 3400 m/s (4 times the speed of sound in the liquid); the pressure at the interface, which is proportional to Σ, reaches 10 GPa; and T(max) reaches 40,000 K. The Rayleigh-Plesset equation together with the time of the collapse can be used to estimate the pressure at the front of the shock wave.

The effect of length and starting year on trend analyses of temperatures in Spanish mainland (1951-2010). Seasonal analyses: Autumn (V)

NASA Astrophysics Data System (ADS)

Salinas Solé, Celia; Peña Angulo, Dhais; Gonzalez HIgaldo, Jose Carlos; Brunetti, MIchele

2017-04-01

In this poster we applied the moving window approach (see Poster I of this collection) to analyze trends of autumn and its corresponding months (September, October, November) temperature mean values of maximum (Tmax) and minimum (Tmin) in Spanish mainland to detect the effects of length period and starting year. Monthly series belong to Monthly Temperature dataset of Spanish mainland (MOTEDAS). Database contains in its grid format of 5236 pixels of monthly series (10x10 km). The threshold used in spatial analyses considers 20% of land under significant trend (p<0.05). The most striking results are as follow: • Seasonal trend analyses of Autumn Tmax show no significance at any temporal Windows. Trends of Tmin are significant in more than 20% of land until 1974-2010. The area affected in Tmin progressively increase from SE to NW. • Monthly trend analyses not detect any significance in Tmax, while in Tmin, particularly in October, an extended area is detected in temporal windows in between 1951-2010 to 1978-2010, but clearly concentrated in the starting years of initial 70´s. Spatial pattern of areas affected significantly seems to be from SE to NW for October, and South-North in September. To conclude autumn trend analyses of Tmax and Tmin in Spanish mainland only detect significant trend in Tmin, mostly located in the 70´s and extending from SE to central areas of study area.

Observational Studies and a Statistical Early Warning of Surface Ozone Pollution in Tangshan, the Largest Heavy Industry City of North China

PubMed Central

Li, Pei; Xin, Jinyuan; Bai, Xiaoping; Wang, Yuesi; Wang, Shigong; Liu, Shixi; Feng, Xiaoxin

2013-01-01

Continuous measurements of surface ozone (O3) and nitrogen oxides (NOX) at an urban site (39°37′N, 118°09′E) in Tangshan, the largest heavy industry city of North China during summertime from 2008 to 2011 are presented. The pollution of O3 was serious in the city. The daily maximum 1 h means (O3_1-hr max) reached 157 ± 55, 161 ± 54, 120 ± 50, and 178 ± 75 μg/m3 corresponding to an excess over the standard rates of 21%, 27%, 10%, and 40% in 2008–2011, respectively. The total oxidant level (OX = O3 + NO2) was high, with seasonal average concentrations up to 100 μg/m3 in summer. The level of OX at a given location was made up of NOX-independent and NOX-dependent contributions. The independent part can be considered as a regional contribution and was about 100 μg/m3 in Tangshan. Statistical early warning analysis revealed that the O3 levels would exceed the standard rate by 50% on the day following a day when the daily average ozone concentration (O3_mean) exceeded 87 μg/m3 and the daily maximum temperature (T_max) exceeded 29 °C. The exceed-standard rate would reach 80% when O3_mean and T_max exceeded 113 μg/m3 and 31 °C. Similarly, the exceed-standard rate would reach 100% when O3_mean and T_max exceeded 127 μg/m3 and 33 °C, respectively. PMID:23485953

High-frequency daily temperature variability in China and its relationship to large-scale circulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Fu-Ting; Fu, Congbin; Qian, Yun

Two measures of intra-seasonal variability, indicated respectively by standard deviations (SD) and day-to-day (DTD) fluctuations denoted by absolute differences between adjacent 2-day periods, as well as their relationships with large-scale circulation patterns were investigated in China during 1962–2008 on the basis of homogenized daily temperature records from 549 local stations and reanalysis data. Our results show that both the SD and DTD of daily minimum temperatures (Tmin) in summer as well as the minimum and maximum temperatures in winter have been decreasing, while the daily maximum temperature (Tmax) variability in summer is fluctuating more, especially over southern China. In summer,more » an attribution analysis indicates that the intensity of the Western Pacific Subtropical High (WPSH) and high-level East Asian Subtropical Jet stream (EASJ) are positively correlated with both SD and DTD, but the correlation coefficients are generally greater with the SD than with the DTD of the daily maximum temperature, Tmax. In contrast, the location of the EASJ shows the opposite correlation pattern, with intensity regarding the correlation with both SD and DTD. In winter, the Arctic Oscillation (AO) is negatively correlated with both the SD and DTD of the daily minimum temperature, but its intra-seasonal variability exhibits good agreement with the SD of the Tmin. The Siberian High acts differently with respect to the SD and DTD of the Tmin, demonstrating a regionally consistent positive correlation with the SD. Overall, the large-scale circulation can well explain the intra-seasonal SD, but DTD fluctuations may be more local and impacted by local conditions, such as changes in the temperature itself, the land surface, and so on.« less

The effect of length and starting year on trend analyses of temperatures in Spanish mainland (1951-2010). Seasonal analyses: Spring (III)

NASA Astrophysics Data System (ADS)

Salinas Solé, Celia; Peña Angulo, Dhais; Gonzalez Hidalgo, Jose Carlos; Brunetti, Michele

2017-04-01

In this poster we applied the moving window approach (see Poster I of this collection) to analyze trends of spring and its corresponding months (March, April, May) temperature mean values of maximum (Tmax) and minimum (Tmin) in Spanish mainland to detect the effects of length period and starting year. Monthly series belong to Monthly Temperature dataset of Spanish mainland (MOTEDAS). Database contains in its grid format of 5236 pixels of monthly series (10x10 km). The threshold used in spatial analyses considers 20% of land under significant trend (p<0.05). The most striking results are as follow: • Seasonal Tmax shows that global trend was positive and significant until the mid 80's with higher values than 75% from between 1954-2010 to 1979-2010, being reduced after to the north region. So, from 1985-2010 no significant trend have been detected. Monthly analyses show differences. March trend is not significant (<20% of area) since 1974-2010, while significant trend in April and May varies between 1961-2010/1979-2010 and 1965-2010/1980-2010 respectively, clearly located in northern midland and Mediterranean coastland. • Spring Tmin trend analyses is significantly (>20%) during all temporal windows, notwithstanding NW do not show global significant trend, and in the most recent temporal windows only affect significantly SE. Monthly analyses also differ. Not significant trend is detected in March from 1979-2010, and from 1985-2010 in May, being April the month in any temporal windows with more than 20% of land affected by significant trend. • Spatial differences are detected between windows (South-North in March, East-West in April-May. We can conclude Tmax trend varies accordingly temporal windows dramatically in spring and no significance has been detected in the recent decades. Northern areas and Mediterranean coastland seems to be the most affected. Monthy Tmax trend spatial analyses confirm the heterogeneity of diurnal temperatures; different spatial gradients in windows have been detected between months. Seasonal Tmin show a more global temporal pattern. Spatial gradients of significance between months have been detected, in some sense contraries to the observed in Tmax.

A Spatio-Temporal Analysis of the Relationship Between Near-Surface Air Temperature and Satellite Land Surface Temperatures Using 17 Years of Data from the ATSR Series

NASA Astrophysics Data System (ADS)

Ghent, D.; Good, E.; Bulgin, C.; Remedios, J. J.

2017-12-01

Surface temperatures (ST) over land have traditionally been measured at weather stations. There are many parts of the globe with very few stations, e.g. across much of Africa, leading to gaps in ST datasets, affecting our understanding of how ST is changing, and the impacts of extreme events. Satellites can provide global ST data but these observations represent how hot the land ST (LST; including the uppermost parts of e.g. trees, buildings) is to touch, whereas stations measure the air temperature just above the surface (T2m). Satellite LST data may only be available in cloud-free conditions and data records are frequently <10-15 years in length. Consequently, satellite LST data have not yet featured widely in climate studies. In this study, the relationship between clear-sky satellite LST and all-sky T2m is characterised in space and time using >17 years of data. The analysis uses a new monthly LST climate data record (CDR) based on the Along-Track Scanning Radiometer (ATSR) series, which has been produced within the European Space Agency GlobTemperature project. The results demonstrate the dependency of the global LST-T2m differences on location, land cover, vegetation and elevation. LSTnight ( 10 pm local solar time) is found to be closely coupled with minimum T2m (Tmin) and the two temperatures generally consistent to within ±5 °C (global median LSTnight- Tmin= 1.8 °C, interquartile range = 3.8 °C). The LSTday ( 10 am local time)-maximum T2m (Tmax) variability is higher because LST is strongly influenced by insolation and surface regime (global median LSTday-Tmax= -0.1 °C, interquartile range = 8.1 °C). Correlations for both temperature pairs are typically >0.9 outside of the tropics. A crucial aspect of this study is a comparison between the monthly global anomaly time series of LST and CRUTEM4 T2m. The time series agree remarkably well, with a correlation of 0.9 and 90% of the CDR anomalies falling within the T2m 95% confidence limits (see figure). This analysis provides independent verification of the 1995-2012 T2m anomaly time series, suggesting that LST can provide a complementary perspective on global ST change. The results presented give justification for increasing use of satellite LST data in climate and weather science, both as an independent variable, and to augment T2m data acquired at weather stations.

Thermopower of CexR1-xB6 (R=La, Pr and Nd)

NASA Astrophysics Data System (ADS)

Kim, Moo‑Sung; Nakai, Yuki; Tou, Hideki; Sera, Masafumi; Iga, Fumitoshi; Takabatake, Toshiro; Kunii, Satoru

2006-06-01

The thermopower, S, of CexR1-xB6 (R=La, Pr, Nd) was investigated. S with a positive sign shows a typical behavior observed in the Ce Kondo system, an increase with decreasing temperature at high temperatures and a maximum at low temperatures. The S values of all the systems at high temperatures are roughly linearly dependent on the Ce concentration, indicating the conservation of the single-impurity character of the Kondo effect in a wide x range. However, the maximum value of S, Smax, and the temperature, Tmax, at which Smax is observed exhibit different x dependences between CexLa1-xB6 and CexR1-xB6 (R=Pr, Nd). In CexLa1-xB6, Tmax, which is ˜8 K in CeB6, decreases with decreasing x and converges to ˜1 K in a very dilute alloy and Smax shows an increase below x ˜ 0.1 after decreasing with decreasing x. In CexR1-xB6 (R=Pr, Nd), Tmax shows a weak x dependence but Smax shows a roughly linear decrease in x. These results are discussed from the standpoint of the chemical pressure effect and the Ce-Ce interaction. S in the long-range ordered phase shows very different behaviors between CexPr1-xB6 and CexNd1-xB6.

Ambient temperature effects on growth of milkfish (Chanos chanos) at aquaculture scale in Blanakan, West Java

NASA Astrophysics Data System (ADS)

A'yun, Q.; Takarina, N. D.

2017-07-01

Growth and survival of fishes can be influenced by temperature [1]. Variation among size like weight and length could be the preference how temperature works on growth of fishes [2]. This could be key factor in determining in production as well as market demand since people like heavy and large fishes. The main purpose of this study was to determine the effects of temperature on the growth of milkfish (Chanos Chanos) on weight and length parameters in fish farms Blanakan. This study conducted to assess the optimal temperature for the growth of fish of different sizes to optimize the culture conditions for raising milkfishes in scale cultivation in Blanakan, West Java. Milkfishes were reared in the aquaculture Blanakan ponds because they can adapt very well. The weight and length of milkfishes were measured together with water temperature. The results showed the temperature min (tmin) and max (tmax) were ranged from 29-35 °C. Based on the result, there were significant differences in mean weight (p = 0.00) between temperature with the fish reared in tmax group having the lowest mean weight (99.87±11.51 g) and fish reared in tmin group having the highest mean weight (277.17±33.76 g). Likewise, the significant differences were also observed in mean length (p = 0.00) between temperature with the fish reared in tmax group having the lowest mean length (176.50±12.50 mm) and fish reared in tmin group having the highest mean length (183.60±23.86 mm). Therefore, this paper confirmed the significant effects of temperature on the fish growth reared in aquaculture ponds. More, maintaining aquaculture to lower temperature can be considered as way to keep growth of milkfish well.

Comparing daily temperature averaging methods: the role of surface and atmosphere variables in determining spatial and seasonal variability

NASA Astrophysics Data System (ADS)

Bernhardt, Jase; Carleton, Andrew M.

2018-05-01

The two main methods for determining the average daily near-surface air temperature, twice-daily averaging (i.e., [Tmax+Tmin]/2) and hourly averaging (i.e., the average of 24 hourly temperature measurements), typically show differences associated with the asymmetry of the daily temperature curve. To quantify the relative influence of several land surface and atmosphere variables on the two temperature averaging methods, we correlate data for 215 weather stations across the Contiguous United States (CONUS) for the period 1981-2010 with the differences between the two temperature-averaging methods. The variables are land use-land cover (LULC) type, soil moisture, snow cover, cloud cover, atmospheric moisture (i.e., specific humidity, dew point temperature), and precipitation. Multiple linear regression models explain the spatial and monthly variations in the difference between the two temperature-averaging methods. We find statistically significant correlations between both the land surface and atmosphere variables studied with the difference between temperature-averaging methods, especially for the extreme (i.e., summer, winter) seasons (adjusted R2 > 0.50). Models considering stations with certain LULC types, particularly forest and developed land, have adjusted R2 values > 0.70, indicating that both surface and atmosphere variables control the daily temperature curve and its asymmetry. This study improves our understanding of the role of surface and near-surface conditions in modifying thermal climates of the CONUS for a wide range of environments, and their likely importance as anthropogenic forcings—notably LULC changes and greenhouse gas emissions—continues.

Indirectly pumped 3.7 THz InGaAs/InAlAs quantum-cascade lasers grown by metal-organic vapor-phase epitaxy.

PubMed

Fujita, Kazuue; Yamanishi, Masamichi; Furuta, Shinichi; Tanaka, Kazunori; Edamura, Tadataka; Kubis, Tillmann; Klimeck, Gerhard

2012-08-27

Device-performances of 3.7 THz indirect-pumping quantum-cascade lasers are demonstrated in an InGaAs/InAlAs material system grown by metal-organic vapor-phase epitaxy. The lasers show a low threshold-current-density of ~420 A/cm2 and a peak output power of ~8 mW at 7 K, no sign of parasitic currents with recourse to well-designed coupled-well injectors in the indirect pump scheme, and a maximum operating temperature of Tmax ~100 K. The observed roll-over of output intensities in current ranges below maximum currents and limitation of Tmax are discussed with a model for electron-gas heating in injectors. Possible ways toward elevation of Tmax are suggested.

A Key Marine Diazotroph in a Changing Ocean: The Interacting Effects of Temperature, CO2 and Light on the Growth of Trichodesmium erythraeum IMS101

PubMed Central

Lawson, Tracy; Geider, Richard J.

2017-01-01

Trichodesmium is a globally important marine diazotroph that accounts for approximately 60 − 80% of marine biological N2 fixation and as such plays a key role in marine N and C cycles. We undertook a comprehensive assessment of how the growth rate of Trichodesmium erythraeum IMS101 was directly affected by the combined interactions of temperature, pCO2 and light intensity. Our key findings were: low pCO2 affected the lower temperature tolerance limit (Tmin) but had no effect on the optimum temperature (Topt) at which growth was maximal or the maximum temperature tolerance limit (Tmax); low pCO2 had a greater effect on the thermal niche width than low-light; the effect of pCO2 on growth rate was more pronounced at suboptimal temperatures than at supraoptimal temperatures; temperature and light had a stronger effect on the photosynthetic efficiency (Fv/Fm) than did CO2; and at Topt, the maximum growth rate increased with increasing CO2, but the initial slope of the growth-irradiance curve was not affected by CO2. In the context of environmental change, our results suggest that the (i) nutrient replete growth rate of Trichodesmium IMS101 would have been severely limited by low pCO2 at the last glacial maximum (LGM), (ii) future increases in pCO2 will increase growth rates in areas where temperature ranges between Tmin to Topt, but will have negligible effect at temperatures between Topt and Tmax, (iii) areal increase of warm surface waters (> 18°C) has allowed the geographic range to increase significantly from the LGM to present and that the range will continue to expand to higher latitudes with continued warming, but (iv) continued global warming may exclude Trichodesmium spp. from some tropical regions by 2100 where temperature exceeds Topt. PMID:28081236

A Key Marine Diazotroph in a Changing Ocean: The Interacting Effects of Temperature, CO2 and Light on the Growth of Trichodesmium erythraeum IMS101.

PubMed

Boatman, Tobias G; Lawson, Tracy; Geider, Richard J

2017-01-01

Trichodesmium is a globally important marine diazotroph that accounts for approximately 60 - 80% of marine biological N2 fixation and as such plays a key role in marine N and C cycles. We undertook a comprehensive assessment of how the growth rate of Trichodesmium erythraeum IMS101 was directly affected by the combined interactions of temperature, pCO2 and light intensity. Our key findings were: low pCO2 affected the lower temperature tolerance limit (Tmin) but had no effect on the optimum temperature (Topt) at which growth was maximal or the maximum temperature tolerance limit (Tmax); low pCO2 had a greater effect on the thermal niche width than low-light; the effect of pCO2 on growth rate was more pronounced at suboptimal temperatures than at supraoptimal temperatures; temperature and light had a stronger effect on the photosynthetic efficiency (Fv/Fm) than did CO2; and at Topt, the maximum growth rate increased with increasing CO2, but the initial slope of the growth-irradiance curve was not affected by CO2. In the context of environmental change, our results suggest that the (i) nutrient replete growth rate of Trichodesmium IMS101 would have been severely limited by low pCO2 at the last glacial maximum (LGM), (ii) future increases in pCO2 will increase growth rates in areas where temperature ranges between Tmin to Topt, but will have negligible effect at temperatures between Topt and Tmax, (iii) areal increase of warm surface waters (> 18°C) has allowed the geographic range to increase significantly from the LGM to present and that the range will continue to expand to higher latitudes with continued warming, but (iv) continued global warming may exclude Trichodesmium spp. from some tropical regions by 2100 where temperature exceeds Topt.

Early and late hot extremes, and elongation of the warm period over Greece

NASA Astrophysics Data System (ADS)

Founda, Dimitra; Giannakopoulos, Christos; Pierros, Fragiskos

2017-04-01

The eastern Mediterranean has been assigned as one of the most responsive areas in climate change, mainly with respect to the occurrence of warmer and drier conditions. In Greece in particular, observations suggest prominent increases in the summer air temperature which in some areas amount to approximately 1 0C/decade since the mid 1970s, while Regional Climate Models simulate further increases in the near and distant future. These changes are coupled with simultaneous increase in the occurrence of hot extremes. In addition to changes in the frequency and intensity of hot extrems, timing of occurrence is also of special interest. Early heat waves in particular, have been found to increase thermal risk in humans. The study explores variations and trends in timing, namely the date of first and last occurrence of hot extremes within the year, and subsequently the hot extremes period (season), defined as the time interval (number of days) between first and last hot extremes occurrence, over Greece. A case study for the area of Athens covering a longer than 100-years period (1897-2015) was conducted first, which will be extended to other Greek areas. Several heat related climatic indices were used, based either on predefined temperature thresholds such as 'tropical days' (daily maximum air temperature, Tmax >30 0C), 'tropical nights' (daily minimum air temperature, Tmin >20 0C), 'hot days' (Tmax >35 0C), or on local climate statistics such as days with Tmax (or Tmin) > 95th percentile. The analysis revealed significant changes in the period of hot extremes and specifically elongation of the period, attributed to early rather than late hot extremes occurrence. An earlier shift of the first tropical day and the first tropical night occurrence by approximately 2 days/decade was found over the study period. An overall elongation of the 'hot days' season by 2.6 days/decade was also observed, which is more prominent since the early 1980s. Over the last three decades, earlier shift of occurrence of days with Tmax > 37 0C and Tmin > 26 0C (corresponding to the 95th percentiles of summer Tmax and Tmin respectively for Athens) was striking, amounting to 8 days/decade. Our findings for the hot extremes period will be used to validate respective simulations of Regional Climate Models downscaled over the areas of interest.

Analysis of trend in temperature and rainfall time series of an Indian arid region: comparative evaluation of salient techniques

NASA Astrophysics Data System (ADS)

Machiwal, Deepesh; Gupta, Ankit; Jha, Madan Kumar; Kamble, Trupti

2018-04-01

This study investigated trends in 35 years (1979-2013) temperature (maximum, Tmax and minimum, Tmin) and rainfall at annual and seasonal (pre-monsoon, monsoon, post-monsoon, and winter) scales for 31 grid points in a coastal arid region of India. Box-whisker plots of annual temperature and rainfall time series depict systematic spatial gradients. Trends were examined by applying eight tests, such as Kendall rank correlation (KRC), Spearman rank order correlation (SROC), Mann-Kendall (MK), four modified MK tests, and innovative trend analysis (ITA). Trend magnitudes were quantified by Sen's slope estimator, and a new method was adopted to assess the significance of linear trends in MK-test statistics. It was found that the significant serial correlation is prominent in the annual and post-monsoon Tmax and Tmin, and pre-monsoon Tmin. The KRC and MK tests yielded similar results in close resemblance with the SROC test. The performance of two modified MK tests considering variance-correction approaches was found superior to the KRC, MK, modified MK with pre-whitening, and ITA tests. The performance of original MK test is poor due to the presence of serial correlation, whereas the ITA method is over-sensitive in identifying trends. Significantly increasing trends are more prominent in Tmin than Tmax. Further, both the annual and monsoon rainfall time series have a significantly increasing trend of 9 mm year-1. The sequential significance of linear trend in MK test-statistics is very strong (R 2 ≥ 0.90) in the annual and pre-monsoon Tmin (90% grid points), and strong (R 2 ≥ 0.75) in monsoon Tmax (68% grid points), monsoon, post-monsoon, and winter Tmin (respectively 65, 55, and 48% grid points), as well as in the annual and monsoon rainfalls (respectively 68 and 61% grid points). Finally, this study recommends use of variance-corrected MK test for the precise identification of trends. It is emphasized that the rising Tmax may hamper crop growth due to enhanced metabolic-activities and shortened crop-duration. Likewise, increased Tmin may result in lesser crop and biomass yields owing to the increased respiration.

The Impacts of Heating Strategy on Soil Moisture Estimation Using Actively Heated Fiber Optics

PubMed Central

Dong, Jianzhi; Agliata, Rosa; Steele-Dunne, Susan; Hoes, Olivier; Bogaard, Thom; Greco, Roberto; van de Giesen, Nick

2017-01-01

Several recent studies have highlighted the potential of Actively Heated Fiber Optics (AHFO) for high resolution soil moisture mapping. In AHFO, the soil moisture can be calculated from the cumulative temperature (Tcum), the maximum temperature (Tmax), or the soil thermal conductivity determined from the cooling phase after heating (λ). This study investigates the performance of the Tcum, Tmax and λ methods for different heating strategies, i.e., differences in the duration and input power of the applied heat pulse. The aim is to compare the three approaches and to determine which is best suited to field applications where the power supply is limited. Results show that increasing the input power of the heat pulses makes it easier to differentiate between dry and wet soil conditions, which leads to an improved accuracy. Results suggest that if the power supply is limited, the heating strength is insufficient for the λ method to yield accurate estimates. Generally, the Tcum and Tmax methods have similar accuracy. If the input power is limited, increasing the heat pulse duration can improve the accuracy of the AHFO method for both of these techniques. In particular, extending the heating duration can significantly increase the sensitivity of Tcum to soil moisture. Hence, the Tcum method is recommended when the input power is limited. Finally, results also show that up to 50% of the cable temperature change during the heat pulse can be attributed to soil background temperature, i.e., soil temperature changed by the net solar radiation. A method is proposed to correct this background temperature change. Without correction, soil moisture information can be completely masked by the background temperature error. PMID:28902141

Spatio-temporal variability of vertical gradients of major meteorological observations around the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Guo, X.; Wang, L.; Tian, L.

2015-12-01

The near-surface air temperature lapse rate (TLR), wind speed gradient (WSG), and precipitation gradient (PG) provide crucial parameters used in models of mountain climate and hydrology. The complex mountain terrain and vast area of the Tibetan Plateau (TP) make such factors particularly important. With daily data from 161 meteorological stations over the past 43 years (1970-2012), we analyse the spatio-temporal variations of TLRs, WSGs, and PGs over and around TP, derived using linear regression methods and dividing the study area into zones based on spatial variations. Results of this study include: (1) The observed TLR varies from -0.46 to -0.73 ∘C (100 m) -1, with averaged TLRs of -0.60,-0.62, and -0.59 ∘C (100 m) -1 for Tmax, Tmin,and Tmean , respectively. The averaged TLR is slightly less than the global mean of -0.65 ∘C (100 m) -1 . The spatial variability of TLR relates to climate conditions, wherein the TLR increases in dry conditions and in cold months (October-April), while it lessens in humid regions and during warm months (May-September). (2) The estimated annual WSG ranges from 0.07 to 0.17m s -1 (100 m) -1. Monthly WSGs show a marked seasonal shift, in which higher WSGs can be explained by the high intensity of prevailing wind. (3) Positive summer PGs vary from 12.08 in the central TP to 26.14 mm (100 m) -1 in northeastern Qinghai and the southern TP, but a reverse gradient prevails in Yunnan and parts of Sichuan Province. (4) The regional warming over TP is more evident in winter, and Tmin demonstrated the most prominent warming compared with Tmax and Tmean. Environments at high elevations experience more rapid changes in temperatures (Tmax, Tmin,and Tmean) than those at low elevations, which is especially true in winter and for Tmin. Furthermore, inter-annual variation of TLRs is linked to elevation-dependent warming.

Interactions between pre- or postservice climatic factors, parity, and weaning-to-first-mating interval for total number of pigs born of female pigs serviced during hot and humid or cold seasons.

PubMed

Iida, R; Koketsu, Y

2014-09-01

The objective of this study was to examine interactions between climatic factors, parity, and weaning-to-first-mating interval (WMI) for total number of pigs born at subsequent parity (TPB) of female pigs serviced during 2 seasons. The present study analyzed records of 27,739 gilts and 127,670 parity records of sows in 95 Japanese herds; the records included females that were serviced between June and September (hot and humid season) or between December and March (cold season) in 2007 through 2009. The climate data were obtained from 20 weather stations located close to the studied herds. Mean daily maximum temperatures (Tmax), mean daily minimum temperatures (Tmin), and daily average relative humidity (RH) for 21 d preservice and 15 d postservice for each female were coordinated with that female's reproductive data. Linear regression models with random intercept and slopes were applied to the data. Mean TPB (±SEM) was 11.9 ± 0.01 pigs. Mean values (ranges) of Tmax in the hot and humid season and Tmin in the cold season were 28.4 (13.6 to 39.8°C) and 2.0°C (-13.2 to 17.6°C), respectively. Also, mean RH in the hot and humid season and the cold season were 73.2 (35 to 98%) and 65.2% (25 to 99%), respectively. In the hot and humid season, TPB in gilts decreased by 0.05 pigs for each degree Celsius increase in preservice Tmax (P < 0.05). However, there was no association between gilt TPB and either postservice Tmax (P = 0.11) or pre- and postservice RH (P ≥ 0.66). In sows, as preservice Tmax increased from 25 to 30°C, TPB in parity groups 1 and 2 or higher decreased by 0.6 and 0.4 pigs, respectively (P < 0.05). Also, sow TPB decreased by 0.1 to 0.4 pigs as postservice Tmax increased from 25 to 30°C (P < 0.05). In sows with WMI of 0 to 12 d, TPB decreased by 0.2 to 0.5 pigs as pre- or postservice Tmax increased from 25 to 30°C (P < 0.05). However, in sows with WMI of 13 d or more, TPB was not associated with pre- or postservice Tmax (P ≥ 0.10). As preservice Tmax increased from 25 to 30°C, TPB in sows under 81.6% RH (90th percentile) decreased by 0.5 pigs (P < 0.05), whereas TPB in sows under 65.7% RH (10th percentile) decreased by only 0.3 pigs (P < 0.05). Postservice RH in the hot and humid season was not associated with sow TPB (P = 0.18). During the cold season there was no association between TPB and pre- or postservice Tmin (P ≥ 0.09) or RH (P ≥ 0.45). Therefore, we recommend that producers apply cooling management for females during periservice in summer to increase TPB.

Attribution of the United States "warming hole": aerosol indirect effect and precipitable water vapor.

PubMed

Yu, Shaocai; Alapaty, Kiran; Mathur, Rohit; Pleim, Jonathan; Zhang, Yuanhang; Nolte, Chris; Eder, Brian; Foley, Kristen; Nagashima, Tatsuya

2014-11-06

Aerosols can influence the climate indirectly by acting as cloud condensation nuclei and/or ice nuclei, thereby modifying cloud optical properties. In contrast to the widespread global warming, the central and south central United States display a noteworthy overall cooling trend during the 20(th) century, with an especially striking cooling trend in summertime daily maximum temperature (Tmax) (termed the U.S. "warming hole"). Here we used observations of temperature, shortwave cloud forcing (SWCF), longwave cloud forcing (LWCF), aerosol optical depth and precipitable water vapor as well as global coupled climate models to explore the attribution of the "warming hole". We find that the observed cooling trend in summer Tmax can be attributed mainly to SWCF due to aerosols with offset from the greenhouse effect of precipitable water vapor. A global coupled climate model reveals that the observed "warming hole" can be produced only when the aerosol fields are simulated with a reasonable degree of accuracy as this is necessary for accurate simulation of SWCF over the region. These results provide compelling evidence of the role of the aerosol indirect effect in cooling regional climate on the Earth. Our results reaffirm that LWCF can warm both winter Tmax and Tmin.

An easy-to-use approach for determining the disintegration ability of disintegrants by analysis of available surface area.

PubMed

Iwao, Yasunori; Tanaka, Shoko; Uchimoto, Takeaki; Noguchi, Shuji; Itai, Shigeru

2013-05-01

With the aim of directly predicting the functionality and mechanism of disintegrants during the disintegration and dissolution of tablets, we investigated an analysis method based on available surface area, which is the surface area of a drug in a formulation in direct contact with the external solvent during dissolution. We evaluated the following disintegrants in this study: sodium starch glycolate (Glycolys), crospovidone (Kollidon CL), carboxymethylcellulose calcium (CMC-Ca), low-substituted hydroxypropylcellulose (L-HPC), and croscarmellose sodium (Ac-Di-Sol). When disintegrant was added to a 50% ethenzamide tablet formulation, an increase in the dissolution rate dependent on disintegrant concentration was observed, according to the type of disintegrant. In addition, the available surface area also differed between disintegrants. For Glycolys, CMC-Ca, and Ac-Di-Sol, a rapid increase in available surface area and a large increase in maximum available surface area (Smax) were observed due to high swellability and wicking, even when the disintegrant concentration was only 1.0%. In contrast, for Kollidon CL and LH-21, a gradual increase in available surface area was observed, depending on the disintegrant concentration. To evaluate the disintegrant ability, Δtmax and ΔSmax were calculated by subtracting peak time (tmax) at 5.0% from that at 1.0% and subtracting Smax at 1.0% from that at 5.0%, respectively, and it was found that the water absorption ratio had strong negative correlations with Δtmax and ΔSmax. Therefore, this study demonstrates that analysis of only available surface area and parameters thereby obtained can directly provide useful information, especially about the disintegration ability of disintegrants. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluation of different methods to estimate daily reference evapotranspiration in ungauged basins in Southern Brazil

NASA Astrophysics Data System (ADS)

Ribeiro Fontoura, Jessica; Allasia, Daniel; Herbstrith Froemming, Gabriel; Freitas Ferreira, Pedro; Tassi, Rutineia

2016-04-01

Evapotranspiration is a key process of hydrological cycle and a sole term that links land surface water balance and land surface energy balance. Due to the higher information requirements of the Penman-Monteith method and the existing data uncertainty, simplified empirical methods for calculating potential and actual evapotranspiration are widely used in hydrological models. This is especially important in Brazil, where the monitoring of meteorological data is precarious. In this study were compared different methods for estimating evapotranspiration for Rio Grande do Sul, the Southernmost State of Brazil, aiming to suggest alternatives to the recommended method (Penman-Monteith-FAO 56) for estimate daily reference evapotranspiration (ETo) when meteorological data is missing or not available. The input dataset included daily and hourly-observed data from conventional and automatic weather stations respectively maintained by the National Weather Institute of Brazil (INMET) from the period of 1 January 2007 to 31 January 2010. Dataset included maximum temperature (Tmax, °C), minimum temperature (Tmin, °C), mean relative humidity (%), wind speed at 2 m height (u2, m s-1), daily solar radiation (Rs, MJ m- 2) and atmospheric pressure (kPa) that were grouped at daily time-step. Was tested the Food and Agriculture Organization of the United Nations (FAO) Penman-Monteith method (PM) at its full form, against PM assuming missing several variables not normally available in Brazil in order to calculate daily reference ETo. Missing variables were estimated as suggested in FAO56 publication or from climatological means. Furthermore, PM was also compared against the following simplified empirical methods: Hargreaves-Samani, Priestley-Taylor, Mccloud, McGuiness-Bordne, Romanenko, Radiation-Temperature, Tanner-Pelton. The statistical analysis indicates that even if just Tmin and Tmax are available, it is better to use PM estimating missing variables from syntetic data than simplified empirical methods evaluated except for Tanner-Pelton and Priestley-Taylor.

Evaluating the predictive performance of empirical estimators of natural mortality rate using information on over 200 fish species

USGS Publications Warehouse

Then, Amy Y.; Hoenig, John M; Hall, Norman G.; Hewitt, David A.

2015-01-01

Many methods have been developed in the last 70 years to predict the natural mortality rate, M, of a stock based on empirical evidence from comparative life history studies. These indirect or empirical methods are used in most stock assessments to (i) obtain estimates of M in the absence of direct information, (ii) check on the reasonableness of a direct estimate of M, (iii) examine the range of plausible M estimates for the stock under consideration, and (iv) define prior distributions for Bayesian analyses. The two most cited empirical methods have appeared in the literature over 2500 times to date. Despite the importance of these methods, there is no consensus in the literature on how well these methods work in terms of prediction error or how their performance may be ranked. We evaluate estimators based on various combinations of maximum age (tmax), growth parameters, and water temperature by seeing how well they reproduce >200 independent, direct estimates of M. We use tenfold cross-validation to estimate the prediction error of the estimators and to rank their performance. With updated and carefully reviewed data, we conclude that a tmax-based estimator performs the best among all estimators evaluated. The tmax-based estimators in turn perform better than the Alverson–Carney method based on tmax and the von Bertalanffy K coefficient, Pauly’s method based on growth parameters and water temperature and methods based just on K. It is possible to combine two independent methods by computing a weighted mean but the improvement over the tmax-based methods is slight. Based on cross-validation prediction error, model residual patterns, model parsimony, and biological considerations, we recommend the use of a tmax-based estimator (M=4.899tmax−0.916">M=4.899t−0.916maxM=4.899tmax−0.916, prediction error = 0.32) when possible and a growth-based method (M=4.118K0.73L∞−0.33">M=4.118K0.73L−0.33∞M=4.118K0.73L∞−0.33 , prediction error = 0.6, length in cm) otherwise.

Contribution of Modis Satellite Image to Estimate the Daily Air Temperature in the Casablanca City, Morocco

NASA Astrophysics Data System (ADS)

Bahi, Hicham; Rhinane, Hassan; Bensalmia, Ahmed

2016-10-01

Air temperature is considered to be an essential variable for the study and analysis of meteorological regimes and chronics. However, the implementation of a daily monitoring of this variable is very difficult to achieve. It requires sufficient of measurements stations density, meteorological parks and favourable logistics. The present work aims to establish relationship between day and night land surface temperatures from MODIS data and the daily measurements of air temperature acquired between [2011-20112] and provided by the Department of National Meteorology [DMN] of Casablanca, Morocco. The results of the statistical analysis show significant interdependence during night observations with correlation coefficient of R2=0.921 and Root Mean Square Error RMSE=1.503 for Tmin while the physical magnitude estimated from daytime MODIS observation shows a relatively coarse error with R2=0.775 and RMSE=2.037 for Tmax. A method based on Gaussian process regression was applied to compute the spatial distribution of air temperature from MODIS throughout the city of Casablanca.

Increasing synchrony of high temperature and low flow in western North American streams: Double trouble for coldwater biota?

Treesearch

Ivan Arismendi; Mohammad Safeeq; Sherri L. Johnson; Jason B Dunham; Roy Haggerty

2013-01-01

Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (Tmax_w) and stream flow minima (Qmin) can create periods of stress for aquatic organisms. In mountainous areas, such as western North America, recent shifts toward an earlier spring peak flow and...

Effect of K loadings on nitrate formation/decomposition and on NOx storage performance of K-based NOx storage-reduction catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Do Heui; Mudiyanselage, Kumudu K.; Szanyi, Janos

2013-10-25

We have investigated nitrate formation and decomposition processes, and measured NOx storage performance on Pt-K2O/Al2O3 catalysts as a function of potassium loading. After NO2 adsorption at room temperature, ionic and bidentate nitrates were observed by fourier transform infra-red (FTIR) spectroscopy. The ratio of the former to the latter species increased with increasing potassium loading up to 10 wt%, and then stayed almost constant with additional K, demonstrating a clear dependence of loading on the morphology of the K species. Although both K2O(10)/Al2O3 and K2O(20)/Al2O3 samples have similar nitrate species after NO2 adsorption, the latter has more thermally stable nitrate speciesmore » as evidenced by FTIR and NO2 temperature programmed desorption (TPD) results. With regard to NOx storage performance, the temperature of maximum NOx uptake (Tmax) is 573 K up to a potassium loading of 10 wt%. As the potassium loading increases from 10 wt% to 20 wt%, Tmax shifted from 573 K to 723 K. Moreover, the amount of NO uptake (38 cm3 NOx/g catal) at Tmax increased more than three times, indicating that efficiency of K in storing NOx is enhanced significantly at higher temperature, in good agreement with the NO2 TPD and FTIR results. Thus, a combination of characterization and NOx storage performance results demonstrates an unexpected effect of potassium loading on nitrate formation and decomposition processes; results important for developing Pt-K2O/Al2O3 for potential applications as high temperature NOx storage-reduction catalysts.« less

Future changes over the Himalayas: Maximum and minimum temperature

NASA Astrophysics Data System (ADS)

Dimri, A. P.; Kumar, D.; Choudhary, A.; Maharana, P.

2018-03-01

An assessment of the projection of minimum and maximum air temperature over the Indian Himalayan region (IHR) from the COordinated Regional Climate Downscaling EXperiment- South Asia (hereafter, CORDEX-SA) regional climate model (RCM) experiments have been carried out under two different Representative Concentration Pathway (RCP) scenarios. The major aim of this study is to assess the probable future changes in the minimum and maximum climatology and its long-term trend under different RCPs along with the elevation dependent warming over the IHR. A number of statistical analysis such as changes in mean climatology, long-term spatial trend and probability distribution function are carried out to detect the signals of changes in climate. The study also tries to quantify the uncertainties associated with different model experiments and their ensemble in space, time and for different seasons. The model experiments and their ensemble show prominent cold bias over Himalayas for present climate. However, statistically significant higher warming rate (0.23-0.52 °C/decade) for both minimum and maximum air temperature (Tmin and Tmax) is observed for all the seasons under both RCPs. The rate of warming intensifies with the increase in the radiative forcing under a range of greenhouse gas scenarios starting from RCP4.5 to RCP8.5. In addition to this, a wide range of spatial variability and disagreements in the magnitude of trend between different models describes the uncertainty associated with the model projections and scenarios. The projected rate of increase of Tmin may destabilize the snow formation at the higher altitudes in the northern and western parts of Himalayan region, while rising trend of Tmax over southern flank may effectively melt more snow cover. Such combined effect of rising trend of Tmin and Tmax may pose a potential threat to the glacial deposits. The overall trend of Diurnal temperature range (DTR) portrays increasing trend across entire area with highest magnitude under RCP8.5. This higher rate of increase is imparted from the predominant rise of Tmax as compared to Tmin.

Evaluation of the CORDEX-Africa multi-RCM hindcast: systematic model errors

NASA Astrophysics Data System (ADS)

Kim, J.; Waliser, Duane E.; Mattmann, Chris A.; Goodale, Cameron E.; Hart, Andrew F.; Zimdars, Paul A.; Crichton, Daniel J.; Jones, Colin; Nikulin, Grigory; Hewitson, Bruce; Jack, Chris; Lennard, Christopher; Favre, Alice

2014-03-01

Monthly-mean precipitation, mean (TAVG), maximum (TMAX) and minimum (TMIN) surface air temperatures, and cloudiness from the CORDEX-Africa regional climate model (RCM) hindcast experiment are evaluated for model skill and systematic biases. All RCMs simulate basic climatological features of these variables reasonably, but systematic biases also occur across these models. All RCMs show higher fidelity in simulating precipitation for the west part of Africa than for the east part, and for the tropics than for northern Sahara. Interannual variation in the wet season rainfall is better simulated for the western Sahel than for the Ethiopian Highlands. RCM skill is higher for TAVG and TMAX than for TMIN, and regionally, for the subtropics than for the tropics. RCM skill in simulating cloudiness is generally lower than for precipitation or temperatures. For all variables, multi-model ensemble (ENS) generally outperforms individual models included in ENS. An overarching conclusion in this study is that some model biases vary systematically for regions, variables, and metrics, posing difficulties in defining a single representative index to measure model fidelity, especially for constructing ENS. This is an important concern in climate change impact assessment studies because most assessment models are run for specific regions/sectors with forcing data derived from model outputs. Thus, model evaluation and ENS construction must be performed separately for regions, variables, and metrics as required by specific analysis and/or assessments. Evaluations using multiple reference datasets reveal that cross-examination, quality control, and uncertainty estimates of reference data are crucial in model evaluations.

Abundance Variations and Flows in Plage Regions Observed with CDS/SOHO

NASA Astrophysics Data System (ADS)

Rank, G.; Bagalá, L. G.; Czaykowska, A.; Haerendel, G.

1999-10-01

We present results from CDS/SOHO observations of the spotless active region NOAA-8208, obtained on 28th April 1998 near disk center. MDI images show a bipolar magnetic configuration. The regions of enhanced He I emission correspond to the areas with strong magnetic flux and also with bright plage areas seen in Ca II and H-alpha images. A high correlation is found between intensity maps of the transition region lines He I (logTmax = 4.3), O III (logTmax = 5.0), and O V (logTmax = 5.4). The line-of-sight velocities of He I reveal a strong downflow in the plage areas. Further, the line-of-sight velocities of He I, O III, and O V are well correlated, showing that the downflow pattern exists up to temperatures of about 0.25 MK. At higher temperatures (Mg VIII at logTmax = 5.8) this flow is not detected, suggesting that material streams into the plage region from sideways in the high transition region. Maps of the electron density in the transition region have been constructed from several line ratios yielding densities of about 9.0 cm-3 in the plage regions, about dex 0.5 cm-3 higher compared to the surrounding. To study the spatial variation of the first ionization potential (FIP) effect, the abundance ratio has been mapped for the ion ratio MgVI/NeVI. The ratio is highly variable on spatial scales down to a few arcsec from photospheric values to enhancements of a factor of 10. The strongest FIP enhancements are not correlated with transition region line emission, but are found outside of the plage regions. Some areas of strong FIP enhancement appear stretched and elongated, suggesting that the material is confined in loop-like structures.

Pressure-induced itinerant electron metamagnetism in UCo0.995Os0.005Al ferromagnet

NASA Astrophysics Data System (ADS)

Mushnikov, N. V.; Andreev, A. V.; Arnold, Z.

2018-05-01

The effect of external hydrostatic pressure on magnetic properties is studied for the UCo0.995Os0.005Al single crystal. At ambient pressure, the ground state is ferromagnetic. Even lowest applied pressure 0.11 GPa is sufficient to suppress ferromagnetism. A sharp metamagnetic transition is observed only in magnetic fields along the c axis of the crystal, similar to previously studied itinerant electron metamagnet UCoAl. Temperature dependence of the susceptibility for various pressures shows a broad maximum at Tmax 20 K. The experimental data are analyzed with the theory of itinerant electron metamagnetism, which considers anisotropic thermal fluctuations of the uranium magnetic moment. The observed pressure dependence of the susceptibility at Tmax and the temperature for the disappearance of the first-order metamagnetic transition are explained with the theory.

Field-acclimated Gossypium hirsutum cultivars exhibit genotypic and seasonal differences in photosystem II thermostability.

PubMed

Snider, John L; Oosterhuis, Derrick M; Collins, Guy D; Pilon, Cristiane; Fitzsimons, Toby R

2013-03-15

Previous investigations have demonstrated that photosystem II (PSII) thermostability acclimates to prior exposure to heat and drought, but contrasting results have been reported for cotton (Gossypium hirsutum). We hypothesized that PSII thermotolerance in G. hirsutum would acclimate to environmental conditions during the growing season and that there would be differences in PSII thermotolerance between commercially-available U.S. cultivars. To this end, three cotton cultivars were grown under dryland conditions in Tifton Georgia, and two under irrigated conditions in Marianna Arkansas. At Tifton, measurements included PSII thermotolerance (T15, the temperature causing a 15% decline in maximum quantum yield), leaf temperatures, air temperatures, midday (1200 to 1400h) leaf water potentials (ΨMD), leaf-air vapor pressure deficit (VPD), actual quantum yield (ΦPSII) and electron transport rate through PSII (ETR) on three sample dates. At Marianna, T15 was measured on two sample dates. Optimal air and leaf temperatures were observed on all sample dates in Tifton, but PSII thermotolerance increased with water deficit conditions (ΨMD=-3.1MPa), and ETR was either unaffected or increased under water-stress. Additionally, T15 for PHY 499 was ∼5°C higher than for the other cultivars examined (DP 0912 and DP 1050). The Marianna site experienced more extreme high temperature conditions (20-30 days Tmax≥35°C), and showed an increase in T15 with higher average Tmax. When average T15 values for each location and sample date were plotted versus average daily Tmax, strong, positive relationships (r(2) from .954 to .714) were observed between Tmax and T15. For all locations T15 was substantially higher than actual field temperature conditions. We conclude that PSII thermostability in G. hirsutum acclimates to pre-existing environmental conditions; PSII is extremely tolerant to high temperature and water-deficit stress; and differences in PSII thermotolerance exist between commercially-available cultivars. Copyright © 2012 Elsevier GmbH. All rights reserved.

Observed and Simulated Urban Heat Island and Urban Cool Island in Las Vegas

NASA Astrophysics Data System (ADS)

Sauceda, Daniel O.

This research investigates the urban climate of Las Vegas and establishes long-term trends relative to the regional climate in an attempt to identify climate disturbances strictly related to urban growth. An experimental surface station network (DRI-UHI) of low-cost surface temperature (T2m) and relative humidity (RH) sensors were designed to cover under-sampled low-intensity residential urban areas, as well as complement the in-city and surrounding rural areas. In addition to the analysis of the surface station data, high-resolution gridded data products (GDPs) from Daymet (1km) and PRISM (800 m) and results from numerical simulations were used to further characterize the Las Vegas climate trends. The Weather Research and Forecasting (WRF) model was coupled with three different models: the Noah Land Surface Model (LSM) and a single- and multi-layer urban canopy model (UCM) to assess the urban related climate disturbances; as well as the model sensitivity and ability to characterize diurnal variability and rural/urban thermal contrasts. The simulations consisted of 1 km grid size for five, one month-long hindcast simulations during November of 2012: (i) using the Noah LSM without UCM treatment, (ii) same as (i) with a single-layer UCM (UCM1), (iii) same as (i) with a multi-layer UCM (UCM2), (iv) removing the City of Las Vegas (NC) and replacing it with predominant land cover (shrub), and (v) same as (ii) with increasing the albedo of rooftops from 0.20 to 0.65 as a potential adaptation scenario known as "white roofing". T2m long-term trends showed a regional warming of minimum temperatures (Tmin) and negligible trends in maximum temperatures (Tmax ). By isolating the regional temperature trends, an observed urban heat island (UHI) of ~1.63°C was identified as well as a daytime urban cool island (UCI) of ~0.15°C. GDPs agree with temperature trends but tend to underpredict UHI intensity by ~1.05°C. The WRF-UCM showed strong correlations with observed T2m (0.85 < rho < 0.95) and vapor pressure (ea ; 0.83 < rho < 0.88), and moderate-to-strong correlations for RH (0.64 < rho < 0.81) at the 95% confidence level. UCM1 shows the best skill and adequately simulates most of the UHI and UCI observed characteristics. Differences of LSM, UCM1, and UCM2 minus NC show simulated effects of warmer in-city Tmin for LSM and UCM2, and cooler in-city Tmax for UCM1 and UCM2. Finally, the white roofing scenario for Las Vegas was not found to significantly impact the UHI effect but has the potential to reduce daytime temperature by 1°-2°C.

α-Pinene secondary organic aerosol at low temperature: chemical composition and implications for particle viscosity

NASA Astrophysics Data System (ADS)

Huang, Wei; Saathoff, Harald; Pajunoja, Aki; Shen, Xiaoli; Naumann, Karl-Heinz; Wagner, Robert; Virtanen, Annele; Leisner, Thomas; Mohr, Claudia

2018-02-01

Chemical composition, size distributions, and degree of oligomerization of secondary organic aerosol (SOA) from α-pinene (C10H16) ozonolysis were investigated for low-temperature conditions (223 K). Two types of experiments were performed using two simulation chambers at the Karlsruhe Institute of Technology: the Aerosol Preparation and Characterization (APC) chamber, and the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) chamber. Experiment type 1 simulated SOA formation at upper tropospheric conditions: SOA was generated in the AIDA chamber directly at 223 K at 61 % relative humidity (RH; experiment termed cold humid, CH) and for comparison at 6 % RH (experiment termed cold dry, CD) conditions. Experiment type 2 simulated SOA uplifting: SOA was formed in the APC chamber at room temperature (296 K) and < 1 % RH (experiment termed warm dry, WD) or 21 % RH (experiment termed warm humid, WH) conditions, and then partially transferred to the AIDA chamber kept at 223 K, and 61 % RH (WDtoCH) or 30 % RH (WHtoCH), respectively. Precursor concentrations varied between 0.7 and 2.2 ppm α-pinene, and between 2.3 and 1.8 ppm ozone for type 1 and type 2 experiments, respectively. Among other instrumentation, a chemical ionization mass spectrometer (CIMS) coupled to a filter inlet for gases and aerosols (FIGAERO), deploying I- as reagent ion, was used for SOA chemical composition analysis. For type 1 experiments with lower α-pinene concentrations and cold SOA formation temperature (223 K), smaller particles of 100-300 nm vacuum aerodynamic diameter (dva) and higher mass fractions (> 40 %) of adducts (molecules with more than 10 carbon atoms) of α-pinene oxidation products were observed. For type 2 experiments with higher α-pinene concentrations and warm SOA formation temperature (296 K), larger particles ( ˜ 500 nm dva) with smaller mass fractions of adducts (< 35 %) were produced. We also observed differences (up to 20 °C) in maximum desorption temperature (Tmax) of individual compounds desorbing from the particles deposited on the FIGAERO Teflon filter for different experiments, indicating that Tmax is not purely a function of a compound's vapor pressure or volatility, but is also influenced by diffusion limitations within the particles (particle viscosity), interactions between particles deposited on the filter (particle matrix), and/or particle mass on the filter. Highest Tmax were observed for SOA under dry conditions and with higher adduct mass fraction; lowest Tmax were observed for SOA under humid conditions and with lower adduct mass fraction. The observations indicate that particle viscosity may be influenced by intra- and inter-molecular hydrogen bonding between oligomers, and particle water uptake, even under such low-temperature conditions. Our results suggest that particle physicochemical properties such as viscosity and oligomer content mutually influence each other, and that variation in Tmax of particle desorptions may have implications for particle viscosity and particle matrix effects. The differences in particle physicochemical properties observed between our different experiments demonstrate the importance of taking experimental conditions into consideration when interpreting data from laboratory studies or using them as input in climate models.

Investigations on cooling with forced flow of He II. Part 2

NASA Astrophysics Data System (ADS)

Srinivasan, R.; Hofmann, A.

The measurements described in Part 1 of this Paper have been extended to a pressure of 7 bar . The value of the conductivity function, f( T), at a temperature greater than Tmax, at which it exhibits a maximum, drops rapidly with increasing pressure. Below Tmax the change in f( T) with pressure is less drastic. The Gorter-Mellink constant, AGM, increases linearly with pressure in the range 1.5-2 K and its pressure coefficient at 1 bar is 0.038 ± 0.01 per bar, independent of temperature. The superfilter is tested at 1.8 K. The flow through the superfilter is Gorter-Mellink flow. The maximum flow rate decreases as the pressure increases. The temperature distribution in the test section with and without flow is adequately described by the one-dimensional model discussed in Part 1. It is concluded that for heat transfer to He II in forced flow there is no advantage in working at pressures > 1 bar. 1 bar = 100 kPa

Tmax Determined Using a Bayesian Estimation Deconvolution Algorithm Applied to Bolus Tracking Perfusion Imaging: A Digital Phantom Validation Study.

PubMed

Uwano, Ikuko; Sasaki, Makoto; Kudo, Kohsuke; Boutelier, Timothé; Kameda, Hiroyuki; Mori, Futoshi; Yamashita, Fumio

2017-01-10

The Bayesian estimation algorithm improves the precision of bolus tracking perfusion imaging. However, this algorithm cannot directly calculate Tmax, the time scale widely used to identify ischemic penumbra, because Tmax is a non-physiological, artificial index that reflects the tracer arrival delay (TD) and other parameters. We calculated Tmax from the TD and mean transit time (MTT) obtained by the Bayesian algorithm and determined its accuracy in comparison with Tmax obtained by singular value decomposition (SVD) algorithms. The TD and MTT maps were generated by the Bayesian algorithm applied to digital phantoms with time-concentration curves that reflected a range of values for various perfusion metrics using a global arterial input function. Tmax was calculated from the TD and MTT using constants obtained by a linear least-squares fit to Tmax obtained from the two SVD algorithms that showed the best benchmarks in a previous study. Correlations between the Tmax values obtained by the Bayesian and SVD methods were examined. The Bayesian algorithm yielded accurate TD and MTT values relative to the true values of the digital phantom. Tmax calculated from the TD and MTT values with the least-squares fit constants showed excellent correlation (Pearson's correlation coefficient = 0.99) and agreement (intraclass correlation coefficient = 0.99) with Tmax obtained from SVD algorithms. Quantitative analyses of Tmax values calculated from Bayesian-estimation algorithm-derived TD and MTT from a digital phantom correlated and agreed well with Tmax values determined using SVD algorithms.

[Usefulness of contact thermography for the evaluation of chemotherapeutic effectiveness in breast cancer].

PubMed

Kurihara, T; Higashi, Y; Suemasu, K; Kanoh, T; Tabei, T; Inoue, K

1993-05-01

We examined temperature differences between a cancerous breast and its counterpart normal one by contact thermography before and after preoperative chemotherapy, and evaluated the relationship between the changes in the thermograms and response to chemotherapy in six patients with breast cancer. We used the following definitions: 1) delta Tmean: temperature differences between a mean temperature of a cancerous breast and that of the contralateral healthy breast; 2) delta Tmax: temperature differences between a cancer-related hyperthermic area in a breast and the mirror area of contralateral breast; 3) and the thermal patterns in thermogram were estimated by the criteria of Tada et al. In responders the thermograms after chemotherapy indicated an improvement in the hyperthermic vascular pattern (HVP) or hyperthermic area and a decrease of delta Tmean and delta Tmax. In contrast, little or no changes were observed in the thermograms of non-responders. Degrees of changes in thermograms reflected the effectiveness of chemotherapy. Our study showed that chemotherapeutic effectiveness may be better evaluated by combining contact thermography with the present method measuring tumor sizes than by only the present one.

The effect of hot days on occupational heat stress in the manufacturing industry: implications for workers' well-being and productivity

NASA Astrophysics Data System (ADS)

Pogačar, Tjaša; Casanueva, Ana; Kozjek, Katja; Ciuha, Urša; Mekjavić, Igor B.; Kajfež Bogataj, Lučka; Črepinšek, Zalika

2018-03-01

Climate change is expected to exacerbate heat stress at the workplace in temperate regions, such as Slovenia. It is therefore of paramount importance to study present and future summer heat conditions and analyze the impact of heat on workers. A set of climate indices based on summer mean (Tmean) and maximum (Tmax) air temperatures, such as the number of hot days (HD: Tmax above 30 °C), and Wet Bulb Globe Temperature (WBGT) were used to account for heat conditions in Slovenia at six locations in the period 1981-2010. Observed trends (1961-2011) of Tmean and Tmax in July were positive, being larger in the eastern part of the country. Climate change projections showed an increase up to 4.5 °C for mean temperature and 35 days for HD by the end of the twenty-first century under the high emission scenario. The increase in WBGT was smaller, although sufficiently high to increase the frequency of days with a high risk of heat stress up to an average of a third of the summer days. A case study performed at a Slovenian automobile parts manufacturing plant revealed non-optimal working conditions during summer 2016 (WBGT mainly between 20 and 25 °C). A survey conducted on 400 workers revealed that 96% perceived the temperature conditions as unsuitable, and 56% experienced headaches and fatigue. Given these conditions and climate change projections, the escalating problem of heat is worrisome. The European Commission initiated a program of research within the Horizon 2020 program to develop a heat warning system for European workers and employers, which will incorporate case-specific solutions to mitigate heat stress.

The effect of hot days on occupational heat stress in the manufacturing industry: implications for workers' well-being and productivity.

PubMed

Pogačar, Tjaša; Casanueva, Ana; Kozjek, Katja; Ciuha, Urša; Mekjavić, Igor B; Kajfež Bogataj, Lučka; Črepinšek, Zalika

2018-03-30

Climate change is expected to exacerbate heat stress at the workplace in temperate regions, such as Slovenia. It is therefore of paramount importance to study present and future summer heat conditions and analyze the impact of heat on workers. A set of climate indices based on summer mean (Tmean) and maximum (Tmax) air temperatures, such as the number of hot days (HD: Tmax above 30 °C), and Wet Bulb Globe Temperature (WBGT) were used to account for heat conditions in Slovenia at six locations in the period 1981-2010. Observed trends (1961-2011) of Tmean and Tmax in July were positive, being larger in the eastern part of the country. Climate change projections showed an increase up to 4.5 °C for mean temperature and 35 days for HD by the end of the twenty-first century under the high emission scenario. The increase in WBGT was smaller, although sufficiently high to increase the frequency of days with a high risk of heat stress up to an average of a third of the summer days. A case study performed at a Slovenian automobile parts manufacturing plant revealed non-optimal working conditions during summer 2016 (WBGT mainly between 20 and 25 °C). A survey conducted on 400 workers revealed that 96% perceived the temperature conditions as unsuitable, and 56% experienced headaches and fatigue. Given these conditions and climate change projections, the escalating problem of heat is worrisome. The European Commission initiated a program of research within the Horizon 2020 program to develop a heat warning system for European workers and employers, which will incorporate case-specific solutions to mitigate heat stress.

Effect of screw torque level on cortical bone pullout strength.

PubMed

Cleek, Tammy M; Reynolds, Karen J; Hearn, Trevor C

2007-02-01

The objectives of this study were 2-fold: (1) to perform detailed analysis of cortical screw tightening stiffness during automated insertion, and (2) to determine the effect of 3 torque levels on the holding strength of the bone surrounding the screw threads as assessed by screw pullout. Ten pairs of ovine tibiae were used with 3 test sites spaced 20 mm apart centered along the shaft. One side of each pair was used for measuring ultimate failure torque (Tmax). These Tmax and bone-density values were used to predict Tmax at contralateral tibia sites. Screws were inserted and tightened to 50%, 70%, and 90% of predicted Tmax at the contralateral sites to encompass the average clinical level of torque (86% Tmax). Pullout tests were performed and maximum force values were normalized by cortical thickness. Torque to failure tests indicated tightening to 86% Tmax occurs after yield and leads to an average 51% loss in stiffness. Normalized pullout strength for screws tightened to 50% Tmax, 70% Tmax, and 90% Tmax were 2525 +/- 244, 2707 +/- 280, and 2344 +/- 346 N, respectively, with a significant difference between 70% Tmax and 90% Tmax groups (P < 0.05). Within the limitations of our study involving the testing of 1 type of screw purchase in ovine tibiae, results demonstrate that clinical levels of lag screw tightening (86% Tmax) are past the yield point of bone. Tightening to these high torque levels can cause damage leading to compromised holding strength. Further research is still required to establish the appropriate level of torque required for achieving optimal fracture fixation and healing.

Variability of Winter Air Temperature in Mid-Latitude Europe

NASA Technical Reports Server (NTRS)

Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

2002-01-01

The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud cover and precipitable water are from the National Centers for Environmental Prediction (NCEP) Reanalysis.

Subseasonal climate variability for North Carolina, United States

NASA Astrophysics Data System (ADS)

Sayemuzzaman, Mohammad; Jha, Manoj K.; Mekonnen, Ademe; Schimmel, Keith A.

2014-08-01

Subseasonal trends in climate variability for maximum temperature (Tmax), minimum temperature (Tmin) and precipitation were evaluated for 249 ground-based stations in North Carolina for 1950-2009. The magnitude and significance of the trends at all stations were determined using the non-parametric Theil-Sen Approach (TSA) and the Mann-Kendall (MK) test, respectively. The Sequential Mann-Kendall (SQMK) test was also applied to find the initiation of abrupt trend changes. The lag-1 serial correlation and double mass curve were employed to address the data independency and homogeneity. Using the MK trend test, statistically significant (confidence level ≥ 95% in two-tailed test) decreasing (increasing) trends by 44% (45%) of stations were found in May (June). In general, trends were decreased in Tmax and increased in Tmin data series in subseasonal scale. Using the TSA method, the magnitude of lowest (highest) decreasing (increasing) trend in Tmax is - 0.050 °C/year (+ 0.052 °C/year) in the monthly series for May (March) and for Tmin is - 0.055 °C/year (+ 0.075 °C/year) in February (December). For the precipitation time series using the TSA method, it was found that the highest (lowest) magnitude of 1.00 mm/year (- 1.20 mm/year) is in September (February). The overall trends in precipitation data series were not significant at the 95% confidence level except that 17% of stations were found to have significant (confidence level ≥ 95% in two-tailed test) decreasing trends in February. The statistically significant trend test results were used to develop a spatial distribution of trends: May for Tmax, June for Tmin, and February for precipitation. A correlative analysis of significant temperature and precipitation trend results was examined with respect to large scale circulation modes (North Atlantic Oscillation (NAO) and Southern Oscillation Index (SOI). A negative NAO index (positive-El Niño Southern Oscillation (ENSO) index) was found to be associated with the decreasing precipitation in February during 1960-1980 (2000-2009). The incremental trend in Tmin in the inter-seasonal (April-October) time scale can be associated with the positive NAO index during 1970-2000.

Impact of Functional Group Modifications on Designer Phenethylamine Induced Hyperthermia.

PubMed

Grecco, Gregory G; Sprague, Jon E

2016-05-16

The popularity of designer phenethylamines such as synthetic cathinones ("bath salts") has led to increased reports of life-threatening hyperthermia. The diversity of chemical modifications has resulted in the toxicological profile of most synthetic cathinones being mostly uncharacterized. Here, we investigated the thermogenic effects of six recently identified designer phenethylamines (4-methylmethamphetamine, methylone, mephedrone, butylone, pentylone, and MDPV) and compared these effects to the established thermogenic agent 3,4-methylenedioxymethamphetamine (MDMA). Specifically, we determined the impact of a β-ketone, α-alkyl, or pyrrolidine functional group on core-body temperature changes. Sprague-Dawley rats (n = 5-6) were administered a dose (30 mg/kg, sc) of a designer phenethylamine or MDMA, and core body temperature measurements were recorded at 30 min intervals for 150 min post treatment. MDMA elicited the greatest maximum temperature change (ΔTmax), and this effect was significantly greater than that of its β-ketone analogue, methylone. Temperature-area under the curves (TAUCs) and ΔTmax were also significantly different between 4-methylmethamphetamine (4-MMA) and its β-ketone analogue mephedrone. Lengthening the α-alkyl chain of methylone to produce butylone and pentylone significantly attenuated the thermogenic response on both TAUCs and ΔTmax compared to those of methylone; however, butylone and pentylone were not different from each other. Pyrrolidine substitution on the N-terminus of pentylone produces 3,4-methylenedioxypyrovalerone (MDPV), which did not significantly alter core body temperature. Thermogenic comparisons of MDMA vs methylone and 4-MMA vs mephedrone indicate that oxidation at the benzylic position significantly attenuates the hyperthermic response. Furthermore, either extending the α-alkyl chain to ethyl and propyl (butylone and pentylone, respectively) or extending the α-alkyl chain and adding a pyrrolidine on the N-terminus (MDPV) significantly blunted the thermogenic effects of methylone. Overall, the present study provides the first structure-activity relationship in vivo toxicological analysis of designer phenethylamines.

Derivation of hydrous pyrolysis kinetic parameters from open-system pyrolysis

NASA Astrophysics Data System (ADS)

Tseng, Yu-Hsin; Huang, Wuu-Liang

2010-05-01

Kinetic information is essential to predict the temperature, timing or depth of hydrocarbon generation within a hydrocarbon system. The most common experiments for deriving kinetic parameters are mainly by open-system pyrolysis. However, it has been shown that the conditions of open-system pyrolysis are deviant from nature by its low near-ambient pressure and high temperatures. Also, the extrapolation of heating rates in open-system pyrolysis to geological conditions may be questionable. Recent study of Lewan and Ruble shows hydrous-pyrolysis conditions can simulate the natural conditions better and its applications are supported by two case studies with natural thermal-burial histories. Nevertheless, performing hydrous pyrolysis experiment is really tedious and requires large amount of sample, while open-system pyrolysis is rather convenient and efficient. Therefore, the present study aims at the derivation of convincing distributed hydrous pyrolysis Ea with only routine open-system Rock-Eval data. Our results unveil that there is a good correlation between open-system Rock-Eval parameter Tmax and the activation energy (Ea) derived from hydrous pyrolysis. The hydrous pyrolysis single Ea can be predicted from Tmax based on the correlation, while the frequency factor (A0) is estimated based on the linear relationship between single Ea and log A0. Because the Ea distribution is more rational than single Ea, we modify the predicted single hydrous pyrolysis Ea into distributed Ea by shifting the pattern of Ea distribution from open-system pyrolysis until the weight mean Ea distribution equals to the single hydrous pyrolysis Ea. Moreover, it has been shown that the shape of the Ea distribution is very much alike the shape of Tmax curve. Thus, in case of the absence of open-system Ea distribution, we may use the shape of Tmax curve to get the distributed hydrous pyrolysis Ea. The study offers a new approach as a simple method for obtaining distributed hydrous pyrolysis Ea with only routine open-system Rock-Eval data, which will allow for better estimating hydrocarbon generation.

Dynamical relationship between wind speed magnitude and meridional temperature contrast: Application to an interannual oscillation in Venusian middle atmosphere GCM

NASA Astrophysics Data System (ADS)

Yamamoto, Masaru; Takahashi, Masaaki

2018-03-01

We derive simple dynamical relationships between wind speed magnitude and meridional temperature contrast. The relationship explains scatter plot distributions of time series of three variables (maximum zonal wind speed UMAX, meridional wind speed VMAX, and equator-pole temperature contrast dTMAX), which are obtained from a Venus general circulation model with equatorial Kelvin-wave forcing. Along with VMAX and dTMAX, UMAX likely increases with the phase velocity and amplitude of a forced wave. In the scatter diagram of UMAX versus dTMAX, points are plotted along a linear equation obtained from a thermal-wind relationship in the cloud layer. In the scatter diagram of VMAX versus UMAX, the apparent slope is somewhat steep in the high UMAX regime, compared with the low UMAX regime. The scatter plot distributions are qualitatively consistent with a quadratic equation obtained from a diagnostic equation of the stream function above the cloud top. The plotted points in the scatter diagrams form a linear cluster for weak wave forcing, whereas they form a small cluster for strong wave forcing. An interannual oscillation of the general circulation forming the linear cluster in the scatter diagram is apparent in the experiment of weak 5.5-day wave forcing. Although a pair of equatorial Kelvin and high-latitude Rossby waves with a same period (Kelvin-Rossby wave) produces equatorward heat and momentum fluxes in the region below 60 km, the equatorial wave does not contribute to the long-period oscillation. The interannual fluctuation of the high-latitude jet core leading to the time variation of UMAX is produced by growth and decay of a polar mixed Rossby-gravity wave with a 14-day period.

Minimally-invasive Ultrasound Devices for Treating Low Back Pain

NASA Astrophysics Data System (ADS)

Nau, William; Diederich, C.; Shu, R.; Kinsey, A.; Lotz, J.; Ferrier, W.; Sutton, J.; Pellegrino, R.

2006-05-01

Catheter-based ultrasound is being investigated for the potential to deliver heat to disc tissue for the treatment of discogenic low back pain. Two ultrasound applicator design configurations were tested: an intradiscal (IDUS) applicator which can be implanted directly within the disc, and an extradiscal (EDUS) applicator which is placed adjacent to the disc. In vitro heating trials were performed in human lumbar cadaveric disc segments instrumented with 24 thermocouples to obtain detailed maps of the temperature distributions. A low temperature elevation heating protocol in which the maximum temperature measured 5 mm away from the applicator is controlled to 52° C for the treatment period, and a high temperature elevation protocol (maximum temperature controlled to >70° C) were evaluated in this study. In vivo experiments were performed in sheep cervical spine using both applicator configurations, and both heating protocols. Steady-state temperature maps, and thermal doses (t43) calculated from the transient temperature data were used to assess regions of thermal damage within the disc. During the in vitro human disc studies using the high temperature protocol, temperatures were maintained at 71.5° ± 0.4°C 5 mm from an IDUS applicator implanted within the annular wall, with a maximum temperature (Tmax) of 78.6°C (t43 > 4.85 × 1010 min) measured 2 mm from the applicator. For the EDUS applicator, the temperature was maintained at 78.7° °C 5 mm from the applicator, with a Tmax of 86.3°C within 1 mm of the applicator surface. In the in vivo sheep studies, steady-state temperatures were maintained at 49.4° ± 0.3°C (t43 = 8.74 × 102 min) and 73.2° ± 0.6°C (t43 = 1.34 × 1010 min) with the IDUS applicator for the low and high temperature protocols, respectively. Using the EDUS applicator, temperatures were maintained at 54.4° ± 3.2°C (t43 = 4.11 × 104 min) and 69.4° ± 2.8°C (t43 = 2.81 × 109 min) for the two protocols. Directional heating was demonstrated with both applicator design configurations. Results from these studies demonstrated the capability to control temperature distributions within targeted regions of the disc using interstitial ultrasound with greater thermal penetration than can be achieved with the RF heating devices currently in clinical use. Thus interstitial ultrasound offers a potential alternative heating modality for the clinical management of low back pain.

Year-round breeding equatorial Larks from three climatically-distinct populations do not use rainfall, temperature or invertebrate biomass to time reproduction

PubMed Central

Ndithia, Henry K.; Matson, Kevin D.; Versteegh, Maaike A.; Muchai, Muchane; Tieleman, B. Irene

2017-01-01

Timing of reproduction in birds is important for reproductive success and is known to depend on environmental cues such as day length and food availability. However, in equatorial regions, where day length is nearly constant, other factors such as rainfall and temperature are thought to determine timing of reproduction. Rainfall can vary at small spatial and temporal scales, providing a highly fluctuating and unpredictable environmental cue. In this study we investigated the extent to which spatio-temporal variation in environmental conditions can explain the timing of breeding of Red-capped Lark, Calandrella cinerea, a species that is capable of reproducing during every month of the year in our equatorial east African study locations. For 39 months in three climatically-distinct locations, we monitored nesting activities, sampled ground and flying invertebrates, and quantified rainfall, maximum (Tmax) and minimum (Tmin) temperatures. Among locations we found that lower rainfall and higher temperatures did not coincide with lower invertebrate biomasses and decreased nesting activities, as predicted. Within locations, we found that rainfall, Tmax, and Tmin varied unpredictably among months and years. The only consistent annually recurring observations in all locations were that January and February had low rainfall, high Tmax, and low Tmin. Ground and flying invertebrate biomasses varied unpredictably among months and years, but invertebrates were captured in all months in all locations. Red-capped Larks bred in all calendar months overall but not in every month in every year in every location. Using model selection, we found no clear support for any relationship between the environmental variables and breeding in any of the three locations. Contrary to popular understanding, this study suggests that rainfall and invertebrate biomass as proxy for food do not influence breeding in equatorial Larks. Instead, we propose that factors such as nest predation, female protein reserves, and competition are more important in environments where weather and food meet minimum requirements for breeding during most of the year. PMID:28419105

Mountain Climates on the Move: Implications for Past and Future Vegetation Shifts in the Northeastern United States

NASA Astrophysics Data System (ADS)

Wason, J. W., III; Dovciak, M.; Bevilacqua, E.

2015-12-01

Climate change in the northeastern United States is expected to shift climatic (temperature) envelopes for spruce-fir forests upslope and northward decreasing their area in the region by 2100. Coarse scale landscape models however, may not incorporate heterogeneity in climatic conditions in mountains that can create climatic refugia for species in high-elevation spruce-fir forests. To determine spatial and temporal trends in climate of mountain spruce-fir forests we measured microclimate at 98 forest plots in 2012 and 2013 on 12 mountains in New York, Vermont, New Hampshire, and Maine. By linking regional climate trends with our spatial climate data we calculated elevational shifts in temperature envelopes during the last 50 years. Additionally we linked our spatial dataset to a range of future climate conditions for 2100 based on Representative Concentration Pathways (1 to 5°C warming). We hypothesized that climates have already changed to an extent that spruce-fir forests should begin to respond and that future climate conditions may shift suitable habitat for spruce-fir forests beyond their current range. We found that regional climate change over the last 50 years has resulted in warming of 0.66 and 1.62°C for average annual daily maximum (Tmax) and minimum (Tmin) temperatures in the region. When linked to our spatial microclimate model, this warming results in a 100 (Tmax) and 312m (Tmin) upslope shift in temperature envelopes. Future climate projections suggest that by 2100 Tmax may shift upslope between 152 and 758m for the 1 and 5°C scenarios respectively, while Tmin may shift upslope between 192 and 962m. Spruce-fir forests typically occupy an elevation range of ~500m suggesting that the climate experienced in these forests 50 years ago may not be found within their elevation range by 2100. These results are discussed in the context of responses of tree populations and growth rates observed along the elevation gradients of northeastern United States.

Quantification of parameters influencing methane generation due to biodegradation of municipal solid waste in landfills and laboratory experiments.

PubMed

Fei, Xunchang; Zekkos, Dimitrios; Raskin, Lutgarde

2016-09-01

The energy conversion potential of municipal solid waste (MSW) disposed of in landfills remains largely untapped because of the slow and variable rate of biogas generation, delayed and inefficient biogas collection, leakage of biogas, and landfill practices and infrastructure that are not geared toward energy recovery. A database consisting of methane (CH4) generation data, the major constituent of biogas, from 49 laboratory experiments and field monitoring data from 57 landfills was developed. Three CH4 generation parameters, i.e., waste decay rate (k), CH4 generation potential (L0), and time until maximum CH4 generation rate (tmax), were calculated for each dataset using U.S. EPA's Landfill Gas Emission Model (LandGEM). Factors influencing the derived parameters in laboratory experiments and landfills were investigated using multi-linear regression analysis. Total weight of waste (W) was correlated with biodegradation conditions through a ranked classification scheme. k increased with increasing percentage of readily biodegradable waste (Br0 (%)) and waste temperature, and reduced with increasing W, an indicator of less favorable biodegradation conditions. The values of k obtained in the laboratory were commonly significantly higher than those in landfills and those recommended by LandGEM. The mean value of L0 was 98 and 88L CH4/kg waste for laboratory and field studies, respectively, but was significantly affected by waste composition with ranges from 10 to 300L CH4/kg. tmax increased with increasing percentage of biodegradable waste (B0) and W. The values of tmax in landfills were higher than those in laboratory experiments or those based on LandGEM's recommended parameters. Enhancing biodegradation conditions in landfill cells has a greater impact on improving k and tmax than increasing B0. Optimizing the B0 and Br0 values of landfilled waste increases L0 and reduces tmax. Copyright © 2015 Elsevier Ltd. All rights reserved.

Return levels of temperature extremes in southern Pakistan

NASA Astrophysics Data System (ADS)

Zahid, Maida; Blender, Richard; Lucarini, Valerio; Caterina Bramati, Maria

2017-12-01

Southern Pakistan (Sindh) is one of the hottest regions in the world and is highly vulnerable to temperature extremes. In order to improve rural and urban planning, it is useful to gather information about the recurrence of temperature extremes. In this work, return levels of the daily maximum temperature Tmax are estimated, as well as the daily maximum wet-bulb temperature TWmax extremes. We adopt the peaks over threshold (POT) method, which has not yet been used for similar studies in this region. Two main datasets are analyzed: temperatures observed at nine meteorological stations in southern Pakistan from 1980 to 2013, and the ERA-Interim (ECMWF reanalysis) data for the nearest corresponding locations. The analysis provides the 2-, 5-, 10-, 25-, 50-, and 100-year return levels (RLs) of temperature extremes. The 90 % quantile is found to be a suitable threshold for all stations. We find that the RLs of the observed Tmax are above 50 °C at northern stations and above 45 °C at the southern stations. The RLs of the observed TWmax exceed 35 °C in the region, which is considered as a limit of survivability. The RLs estimated from the ERA-Interim data are lower by 3 to 5 °C than the RLs assessed for the nine meteorological stations. A simple bias correction applied to ERA-Interim data improves the RLs remarkably, yet discrepancies are still present. The results have potential implications for the risk assessment of extreme temperatures in Sindh.

Conductive reduced graphene oxide/MnO2 carbonized cotton fabrics with enhanced electro -chemical, -heating, and -mechanical properties

NASA Astrophysics Data System (ADS)

Tian, Mingwei; Du, Minzhi; Qu, Lijun; Zhang, Kun; Li, Hongliang; Zhu, Shifeng; Liu, Dongdong

2016-09-01

Versatile and ductile conductive carbonized cotton fabrics decorated with reduced graphene oxide (rGO)/manganese dioxide (MnO2) are prepared in this paper. In order to endow multifunction to cotton fabric, graphene oxide (GO) is deposited on cotton fibers by simple dip-coating route. MnO2 nanoparticles are assembled on the surface of cotton fabric through in-situ chemical solution deposition. MnO2/GO@cotton fabrics are carbonized to achieve conductive fabric (MnO2/rGO@C). The morphologies and structures of obtained fabrics are characterized by SEM, XRD, ICP and element analysis, and their electro-properties including electro-chemical, electro-heating and electro-mechanical properties are evaluated. The MnO2/rGO@C yields remarkable specific capacitance of 329.4 mA h/g at the current density of 100 mA/g, which is more than 40% higher than that of the control carbonized cotton fabric (231 mA h/g). Regarding electro-heating properties, the temperature of MnO2/rGO@C fabric could be monotonically increased to the steady-state maximum temperatures (ΔTmax) of 36 °C within 5 min under the applied voltage 15 V while the ΔTmax = 17 °C of the control case. In addition, MnO2/rGO@C exhibits repeatable electro-mechanical properties and its normalized resistance (R-R0)/R0 could reach 0.78 at a constant strain (curvature = 0.6 cm-1). The MnO2/rGO@C fabric is versatile, scalable, and adaptable to a wide variety of smart textiles applications.

Cold denaturation and 2H2O stabilization of a staphylococcal nuclease mutant.

PubMed Central

Antonino, L C; Kautz, R A; Nakano, T; Fox, R O; Fink, A L

1991-01-01

Cold denaturation is now recognized as a general property of proteins but has been observed only under destabilizing conditions, such as moderate denaturant concentration or low pH. By destabilizing the protein using site-directed mutagenesis, we have observed cold denaturation at pH 7.0 in the absence of denaturants in a mutant of staphylococcal nuclease, which we call NCA S28G for a hybrid protein between staphylococcal nuclease and concanavalin A in which there is the point mutation Ser-28----Gly. The temperature of maximum stability (tmax) as determined by circular dichroism (CD) was 18.1 degrees C, and the midpoints of the thermal unfolding transitions (tm) were 0.6 degrees C and 30.0 degrees C. These values may be compared with the tm of 52.5 degrees C for wild-type staphylococcal nuclease, for which no cold denaturation was observed under these conditions. When the stability of the mutant was examined in 2H2O by NMR, CD, or fluorescence, a substantial increase in the amount of folded protein at the tmax was noted as well as a decrease in tmax, reflecting increased stability. PMID:1652762

MOnthly TEmperature DAtabase of Spain 1951-2010: MOTEDAS. (1) Quality control

NASA Astrophysics Data System (ADS)

Peña-Angulo, Dhais; Cortesi, Nicola; Simolo, Claudia; Stepanek, Peter; Brunetti, Michele; González-Hidalgo, José Carlos

2014-05-01

The HIDROCAES project (Impactos Hidrológicos del Calentamiento Global en España, Spanish Ministery of Research CGL2011-27574-C02-01) is focused on the high resolution in the Spanish continental land of the warming processes during the 1951-2010. To do that the Department of Geography (University of Zaragoza, Spain), the Hydrometeorological Service (Brno Division, Chezck Republic) and the ISAC-CNR (Bologna, Italy) are developing the new dataset MOTEDAS (MOnthly TEmperature DAtabase of Spain), from which we present a collection of poster to show (1) the general structure of dataset and quality control; (2) the analyses of spatial correlation of monthly mean values of maximum (Tmax) and minimum (Tmin temperature; (3) the reconstruction processes of series and high resolution grid developing; (4) the first initial results of trend analyses of annual, seasonal and monthly range mean values. MOTEDAS has been created after exhaustive analyses and quality control of the original digitalized data of the Spanish National Meteorological Agency (Agencia Estatal de Meteorología, AEMET). Quality control was applied without any prior reconstruction, i.e. on original series. Then, from the total amount of series stored at AEMet archives (more than 4680) we selected only those series with at least 10 years of data (i.e. 120 months, 3066 series) to apply a quality control and reconstruction processes (see Poster MOTEDAS 3). Length of series was Tmin, upper and lower thresholds of absolute data, etc), and by comparison with reference series (see Poster MOTEDAS 3, about reconstruction). Anomalous data were considered when difference between Candidate and Reference series were higher than three times the interquartile distance. The total amount of monthly suspicious data recognized and discarded at the end of this analyses was 7832 data for Tmin, and 8063 for Tmax data; they represent less than 0,8% of original total monthly data, for both Tmax and Tmin. No spatial pattern was detected in the suspicious data; month by month Tmin shows maximum detection in summer months, while Tmax does not show any monthly pattern. Secondly, the homogeneity analyses was performed on the list of series free of anomalous data by using an arrays of test (SNHT, Bivariate, T de Student and Pettit) after new reference series calculated with data free of anomalous. The tests were applied at monthly, seasonal and annual scale (i.e. 17 times per method). Statistical inhomogeneity detections were accepted as follows: Three annual detections (monthly, seasonal, annual) must be found in SNHT or Bivariate test. The total amount of detections by the four tests was greater than 5% of the total possible detection per year. Before any correction we examined the Candidate and reference series chart. Proclim and Anclim software were used during all the processes The total amount of series affected by inhomogeneities was 1013 (Tmax) and 1011 (Tmin), i.e. 1/3 of original series was considered as inhomogeneous. We notice that identified inhomogeneous series in Tmax and Tmin usually do not coincide. This apparently small amount of series compared with previous work could be originated because of the mean length of series is around 15-20 years. References. Stepánek P. 2008a. AnClim - software for time series analysis (for Windows 95/NT). Department of Geography, Faculty of Natural Sciences, MU, Brno, 1.47 B. Stepánek P.. 2008b. ProClimDB - Software for Processing Climatological Datasets. CHMI, Regional office, Brno.

Variation in absorption and half-life of hydrocortisone influence plasma cortisol concentrations.

PubMed

Hindmarsh, Peter C; Charmandari, Evangelia

2015-04-01

Hydrocortisone therapy should be individualized in congenital adrenal hyperplasia (CAH) patients to avoid over and under replacement. We have assessed how differences in absorption and half-life of cortisol influence glucocorticoid exposure. Forty-eight patients (21 M) aged between 6·1 and 20·3 years with CAH due to CYP21A2 deficiency were studied. Each patient underwent a 24-h plasma cortisol profile with the morning dose used to calculate absorption parameters along with an intravenous (IV) hydrocortisone (15 mg/m(2) body surface area) bolus assessment of half-life. Parameters derived were maximum plasma concentration (Cmax ), time of maximum plasma concentration (tmax ), time to attaining plasma cortisol concentration <100 nmol/l and half-life of cortisol. Mean half-life was 76·5 ± 5·2 (range 40-225·3) min, Cmax 780·7 ± 61·6 nmol/l and tmax 66·7 (range 20-118) min. Time taken to a plasma cortisol concentration less than 100 nmol/l was 289 (range 140-540) min. Those with a fast half-life and slow tmax took longest to reach a plasma cortisol concentration less than 100 nmol/l (380 ± 34·6 min), compared to those with a slow half-life and fast tmax (298 ± 34·8 min) and those with a fast half-life and fast tmax (249·5 ± 14·4 min) (One-way anovaF = 4·52; P = 0·009). Both rate of absorption and half-life of cortisol in the circulation play important roles in determining overall exposure to oral glucocorticoid. Dose regimens need to incorporate estimates of these parameters into determining the optimum dosing schedule for individuals. © 2014 John Wiley & Sons Ltd.

An extended linear scaling method for downscaling temperature and its implication in the Jhelum River basin, Pakistan, and India, using CMIP5 GCMs

NASA Astrophysics Data System (ADS)

Mahmood, Rashid; JIA, Shaofeng

2017-11-01

In this study, the linear scaling method used for the downscaling of temperature was extended from monthly scaling factors to daily scaling factors (SFs) to improve the daily variations in the corrected temperature. In the original linear scaling (OLS), mean monthly SFs are used to correct the future data, but mean daily SFs are used to correct the future data in the extended linear scaling (ELS) method. The proposed method was evaluated in the Jhelum River basin for the period 1986-2000, using the observed maximum temperature (Tmax) and minimum temperature (Tmin) of 18 climate stations and the simulated Tmax and Tmin of five global climate models (GCMs) (GFDL-ESM2G, NorESM1-ME, HadGEM2-ES, MIROC5, and CanESM2), and the method was also compared with OLS to observe the improvement. Before the evaluation of ELS, these GCMs were also evaluated using their raw data against the observed data for the same period (1986-2000). Four statistical indicators, i.e., error in mean, error in standard deviation, root mean square error, and correlation coefficient, were used for the evaluation process. The evaluation results with GCMs' raw data showed that GFDL-ESM2G and MIROC5 performed better than other GCMs according to all the indicators but with unsatisfactory results that confine their direct application in the basin. Nevertheless, after the correction with ELS, a noticeable improvement was observed in all the indicators except correlation coefficient because this method only adjusts (corrects) the magnitude. It was also noticed that the daily variations of the observed data were better captured by the corrected data with ELS than OLS. Finally, the ELS method was applied for the downscaling of five GCMs' Tmax and Tmin for the period of 2041-2070 under RCP8.5 in the Jhelum basin. The results showed that the basin would face hotter climate in the future relative to the present climate, which may result in increasing water requirements in public, industrial, and agriculture sectors; change in the hydrological cycle and monsoon pattern; and lack of glaciers in the basin.

Late Pleistocene environments of the western Noatak basin, northwestern Alaska

USGS Publications Warehouse

Elias, S.A.; Hamilton, T.D.; Edwards, M.E.; Beget, J.E.; Krumhardt, A.P.; Lavoie, C.

1999-01-01

Glacial Lake Noatak formed repeatedly during middle and late Pleistocene time as expanding glaciers from the DeLong Mountains blocked the Noatak River valley. Downcutting by the Noatak River has exposed thick sediment successions in bluffs up to 86 m high. Two river bluffs, Nk-26 and Nk-29A, contain correlative organic-rich flood-plain deposits that were formed during and after deposition of the Old Crow tephra at about the transition between oxygen isotope stage 6 and oxygen isotope stage 5, at the beginning of the last interglaciation. Both bluffs also contain older interglacial or interstadial flood-plain deposits of uncertain age. Pollen and beetle remains were recovered from the older and younger flood-plain deposits at each bluff. Pollen from the younger flood-plain deposits suggests tundra vegetation with local dominance of sedge. Juniperus abundances were locally high, especially around the time of Old Crow tephra deposition. Mutual climatic range (MCR) estimates from the insect fossil assemblages suggest that mean summer temperatures (Tmax) near the time of Old Crow tephra deposition were about 2 ??C colder than modern; mean winter temperatures were very similar to those of today. A younger sample from the same interglacial deposit yielded a Tmax estimate of 2 ??C warmer than modern, signaling interglacial warming. Pollen from the older interglacial deposit at Nk-29A suggests mesic tundra, with boreal forest more distant than it is today. MCR analysis of a possibly correlative older interglacial deposit at Nk-26 suggests a Tmax about 2 ??C below present.

Relationships between extraction and metabolism of glucose, blood flow, and tissue blood volume in regions of rat brain.

PubMed

Cremer, J E; Cunningham, V J; Seville, M P

1983-09-01

Studies were made on the relationships between the rate of glucose metabolism, the transport of glucose between plasma and brain, cerebral blood flow, and blood content. Conscious control rats were compared with rats with intense tremors induced with cismethrin. The influence of plasma glucose concentration was studied by fasting some animals overnight prior to the induction of tremors. Mean plasma glucose was 8.83 mM in controls, 12.57 mM in fed rats with tremors, and 4.94 mM in rats fasted overnight prior to induction of tremors. Of 12 brain regions studied, nine showed an increased rate of glucose utilization in both fed and fasted trembling rats. Cerebellum had the highest percentage increase (200%). Rates of unidirectional glucose influx in fed trembling rats were significantly greater than those in controls in eight regions. In fasted animals, rates were the same as in controls, except in cerebellum, where it was 1.6 times higher. These high rates of glucose influx at low plasma glucose concentrations were indicative of a change in kinetic parameters of glucose transport. Unidirectional glucose influx rates were transformed to estimates of maximal transport rates (Tmax), based on the Michaelis-Menten equation. Average plasma glucose concentrations in regional capillaries (c) were calculated and shown to be maintained at values close to arterial plasma glucose concentrations (Ca), in all brain regions of each group. In trembling rats, Tmax for each brain region was higher than that in controls. In fasted rats with tremors, Tmax was higher in several brain regions than in fed rats. Tmax in cerebellum was 3.37, 4.71, and 7.89 mumol g-1 min-1 in control, fed trembling, and fasted trembling rats, respectively. Blood flow increased significantly in all regions in rats with tremors and was higher in fasted than in fed animals. There was only a weak correlation between blood flow and Tmax. Blood content of several regions increased in rats with tremors, and there was a strong correlation between Tmax and tissue blood volume. Results are consistent with localized regulatory links between blood flow, capillary surface area, and glucose transport in response to metabolic demand and hypoglycaemia. These involve changes in the linear velocity of blood through capillaries and in the extent of capillary recruitment.

Does maximum torque mean optimal pullout strength of screws?

PubMed

Tankard, Sara E; Mears, Simon C; Marsland, Daniel; Langdale, Evan R; Belkoff, Stephen M

2013-04-01

To determine the relationship between insertion torque and pullout strength of 3.5-mm-diameter cortical screws in cadaveric humeri with different bone mineral densities (BMDs). Five pairs of human humeri from each of 3 BMD groups (normal, osteopenic, and osteoporotic) were used. Holes were drilled in each humerus, and maximum insertion torque (T(max)) was measured by tightening a screw until stripping occurred. In the remaining holes, screws were tightened to 50%, 70%, or 90% of the T(max). A servohydraulic testing machine pulled each screw out at 1 mm/s while resulting force and axial displacement were recorded at 10 Hz. The authors checked for an effect of insertion torque (percent T(max)) on pullout strength using a general linearized and latent mixed model (Stata10), controlling for cortical thickness and BMD (T-score). Pullout strength for normal and osteoporotic bone was greatest for screws inserted to 50% T(max) and was significantly greater than that at T(max) but not significantly different from that at 70% or 90% T(max). For osteopenic bone, pullout strength was greatest at 70% peak torque, but it was not significantly different from the pullout strength at the 50% or 90% T(max) levels. Tightening screws beyond 50% T(max) does not increase pullout strength of the screw and may place bone at risk for damage that might result in loss of fixation. Even after adjusting for bone thickness and density, there is no clear relationship between pullout strength and screw torque.

Regional climate change study requires new temperature datasets

NASA Astrophysics Data System (ADS)

Wang, K.; Zhou, C.

2016-12-01

Analyses of global mean air temperature (Ta), i. e., NCDC GHCN, GISS, and CRUTEM4, are the fundamental datasets for climate change study and provide key evidence for global warming. All of the global temperature analyses over land are primarily based on meteorological observations of the daily maximum and minimum temperatures (Tmax and Tmin) and their averages (T2) because in most weather stations, the measurements of Tmax and Tmin may be the only choice for a homogenous century-long analysis of mean temperature. Our studies show that these datasets are suitable for long-term global warming studies. However, they may introduce substantial bias in quantifying local and regional warming rates, i.e., with a root mean square error of more than 25% at 5°x 5° grids. From 1973 to 1997, the current datasets tend to significantly underestimate the warming rate over the central U.S. and overestimate the warming rate over the northern high latitudes. Similar results revealed during the period 1998-2013, the warming hiatus period, indicate the use of T2 enlarges the spatial contrast of temperature trends. This because T2 over land only sample air temperature twice daily and cannot accurately reflect land-atmosphere and incoming radiation variations in the temperature diurnal cycle. For better regional climate change detection and attribution, we suggest creating new global mean air temperature datasets based on the recently available high spatiotemporal resolution meteorological observations, i.e., daily four observations weather station since 1960s, These datasets will not only help investigate dynamical processes on temperature variances but also help better evaluate the reanalyzed and modeled simulations of temperature and make some substantial improvements for other related climate variables in models, especially over regional and seasonal aspects.

Regional climate change study requires new temperature datasets

NASA Astrophysics Data System (ADS)

Wang, Kaicun; Zhou, Chunlüe

2017-04-01

Analyses of global mean air temperature (Ta), i. e., NCDC GHCN, GISS, and CRUTEM4, are the fundamental datasets for climate change study and provide key evidence for global warming. All of the global temperature analyses over land are primarily based on meteorological observations of the daily maximum and minimum temperatures (Tmax and Tmin) and their averages (T2) because in most weather stations, the measurements of Tmax and Tmin may be the only choice for a homogenous century-long analysis of mean temperature. Our studies show that these datasets are suitable for long-term global warming studies. However, they may have substantial biases in quantifying local and regional warming rates, i.e., with a root mean square error of more than 25% at 5 degree grids. From 1973 to 1997, the current datasets tend to significantly underestimate the warming rate over the central U.S. and overestimate the warming rate over the northern high latitudes. Similar results revealed during the period 1998-2013, the warming hiatus period, indicate the use of T2 enlarges the spatial contrast of temperature trends. This is because T2 over land only samples air temperature twice daily and cannot accurately reflect land-atmosphere and incoming radiation variations in the temperature diurnal cycle. For better regional climate change detection and attribution, we suggest creating new global mean air temperature datasets based on the recently available high spatiotemporal resolution meteorological observations, i.e., daily four observations weather station since 1960s. These datasets will not only help investigate dynamical processes on temperature variances but also help better evaluate the reanalyzed and modeled simulations of temperature and make some substantial improvements for other related climate variables in models, especially over regional and seasonal aspects.

Weekly Oscillation of Daily Climatology of Air Temperature: Implication for Anthropogenic Attribution

NASA Astrophysics Data System (ADS)

Jiang, S.; Wang, K.

2016-12-01

During national holiday and weekend, human activity and anthropogenic emission are expected to be much less than those during workday. Therefore, the contrast of environmental factors (i.e., air temperature and air quality) between national holiday (or weekend) and workday has been attributed to anthropogenic impact. For example, daily maximum (Tmax), minimum (Tmin) and mean (Tmean) air temperatures during the Chinese Spring Festival holiday were found to be 0. 6°C less than those of nearby workdays. We evaluated the contrasts using daily meteorological observations collected at 2479 stations in China from 1961 to 2015. The contrasts were evaluated with two methods. The first directly compared air temperatures between Chinese Spring Festival holiday and nearby workdays. The second first composited a daily climatology of air temperatures centered on the first day of Chinese Spring Festival holiday, and the seasonal cycles of air temperatures were then removed using polynomial regressions. The average of the derived daily deviation of air temperatures can be regarded as anthropogenic impact of Chinese Spring Festival holiday. We found that these two methods obtained nearly the same results. However, we found that the so-called anthropogenic impact during Chinese Spring Festival was not unique because the daily deviations of air temperatures had obvious weekly oscillations. The daily deviations of air temperature had periods of 7 days and 9 days, which explain 60% of the variance of daily deviations of Tmax, Tmin, and Tmean. These results indicate that the so-called anthropogenic impacts are primarily caused by natural variability, i.e., weekly oscillations of the air temperatures. This study also has great implication for the studies on weekend effect of the environmental factors.

Application of infrared thermography for online monitoring of wall temperatures in inductively coupled plasma torches with conventional and low-flow gas consumption

NASA Astrophysics Data System (ADS)

Engelhard, Carsten; Scheffer, Andy; Maue, Thomas; Hieftje, Gary M.; Buscher, Wolfgang

2007-10-01

Inductively coupled plasma (ICP) sources typically used for trace elemental determination and speciation were investigated with infrared (IR) thermography to obtain spatially resolved torch temperature distributions. Infrared thermographic imaging is an excellent tool for the monitoring of temperatures in a fast and non-destructive way. This paper presents the first application of IR thermography to inductively coupled plasma torches and the possibility to investigate temperatures and thermal patterns while the ICP is operating and despite background emission from the plasma itself. A fast and easy method is presented for the determination of temperature distributions and stress features within ICP torches. Two different ICP operating torches were studied: a commercially available Fassel-type ICP unit with 14 L min - 1 total Ar consumption and a SHIP torch with the unusually low Ar flow of 0.6 L min - 1 . Spatially resolved infrared images of both torches were obtained and laterally resolved temperature profiles were extracted. After temperature-resolved calibration of the emissivity (between 0.5 and 0.35 at 873-1323 K) and transmission (20% between 3.75 and 4.02 μm) of the fused quartz used in the torch construction, an image correction was applied. Inhomogeneous temperature distributions with locally defined stress areas in the conventional Fassel-type torch were revealed. As a general trend, it was found that the SHIP torch exhibited higher temperatures ( Tmax = 1580 K) than the conventional torch ( Tmax = 730 K). In the former case, torch sites with efficient and inefficient cooling were discovered and the external flow of cooling air (24-48 m s - 1 ) was identified as the limiting factor.

Kinetic analysis of superparamagnetic iron oxide nanoparticles in the liver of body-temperature-controlled mice using dynamic susceptibility contrast magnetic resonance imaging and an empirical mathematical model.

PubMed

Murase, Kenya; Assanai, Purapan; Takata, Hiroshige; Matsumoto, Nozomi; Saito, Shigeyoshi; Nishiura, Motoko

2015-06-01

The purpose of this study was to develop a method for analyzing the kinetic behavior of superparamagnetic iron oxide nanoparticles (SPIONs) in the murine liver under control of body temperature using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) and an empirical mathematical model (EMM). First, we investigated the influence of body temperature on the kinetic behavior of SPIONs in the liver by controlling body temperature using our temperature-control system. Second, we investigated the kinetic behavior of SPIONs in the liver when mice were injected with various doses of GdCl3, while keeping the body temperature at 36°C. Finally, we investigated it when mice were injected with various doses of zymosan, while keeping the body temperature at 36°C. We also investigated the effect of these substances on the number of Kupffer cells by immunohistochemical analysis using the specific surface antigen of Kupffer cells (CD68). To quantify the kinetic behavior of SPIONs in the liver, we calculated the upper limit of the relative enhancement (A), the rates of early contrast uptake (α) and washout or late contrast uptake (β), the parameter related to the slope of early uptake (q), the area under the curve (AUC), the maximum change of transverse relaxation rate (ΔR2) (ΔR2(max)), the time to ΔR2(max) (Tmax), and ΔR2 at the last time point (ΔR2(last)) from the time courses of ΔR2 using the EMM. The β and Tmax values significantly decreased and increased, respectively, with decreasing body temperature, suggesting that the phagocytic activity of Kupffer cells is significantly affected by body temperature. The AUC, ΔR2(max), and ΔR2(last) values decreased significantly with increasing dose of GdCl3, which was consistent with the change in the number of CD68-positive cells. They increased with increasing dose of zymosan, which was also consistent with the change in the number of CD68-positive cells. These results suggest that AUC, ΔR2(max), and ΔR2(last) reflect the number of Kupffer cells. In conclusion, we presented a method for analyzing the kinetic behavior of SPIONs in the liver using DSC-MRI and EMM, and investigated the influence of body temperature, GdCl3, and zymosan using body-temperature-controlled mice. The present study suggests that control of body temperature is essential for investigating the kinetic behavior of SPIONs in the liver and that our method will be applicable and useful for quantifying the responses of Kupffer cells to various drugs under control of body temperature. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of wine and vinegar processing of Rhizoma Corydalis on the tissue distribution of tetrahydropalmatine, protopine and dehydrocorydaline in rats.

PubMed

Dou, Zhiying; Li, Kefeng; Wang, Ping; Cao, Liu

2012-01-18

Vinegar and wine processing of medicinal plants are two traditional pharmaceutical techniques which have been used for thousands of years in China. Tetrahydropalmatine (THP), dehydrocorydaline (DHC) and protopine are three major bioactive molecules in Rhizoma Corydalis. In this study, a simple and reliable HPLC method was developed for simultaneous analysis of THP, DHC and protopine in rat tissues after gastric gavage administration of Rhizoma Corydalis. The validated HPLC method was successfully applied to investigate the effect of wine and vinegar processing on the compounds' distribution in rat tissues. Our results showed that processing mainly affect the T(max) and mean residence time (MRT) of the molecules without changing their C(max) and AUC(0-24)( )(h) Vinegar processing significantly increased the T(max) of DHC in heart, kidney, cerebrum, cerebrellum, brain stem and striatum and prolonged the T(max) of protopine in brain. No significant changes were observed on the T(max) of THP in rat tissues after vinegar processing. Wine processing reduced the T(max) of protopine and DHC in liver and spleen and T(max) of protopine in lung, but increased the T(max) of THP in all the rat tissues examined. To our knowledge, this is the first report on the effects of processing on the tissue distribution of the bioactive molecules from Rhizoma Corydalis.

Temporal characteristics of nitric oxide-, prostaglandin-, and EDHF-mediated components of endothelium-dependent vasodilation in the kidney.

PubMed

Dautzenberg, Marcel; Just, Armin

2013-11-01

Endothelium-dependent vasodilation is mediated by nitric oxide (NO), prostaglandins (PG), and endothelium-derived hyperpolarizing factor (EDHF). We studied the contributions and temporal characteristics of these components in the renal vasodilator responses to acetylcholine (ACh) and bradykinin (BK) and in the buffering of vasoconstrictor responses to norepinephrine (NE) and angiotensin II (ANG II). Renal blood flow (RBF) and vascular conductance (RVC) were studied in anesthetized rats in response to renal arterial bolus injections before and after inhibition of NO-synthase (N(G)-nitro-L-arginine methyl ester, L-NAME), cyclooxygenase (indomethacin, INDO), or both. ACh increased RVC peaking at maximal time (tmax) = 29 s. L-NAME (n = 8) diminished the integrated response and made it substantially faster (tmax = 18 s). The point-by-point difference caused by L-NAME (= NO component) integrated to 74% of control and was much slower (tmax = 38 s). INDO (n = 9) reduced the response without affecting tmax (36 vs. 30 s). The difference (= PG) reached 21% of the control with tmax = 25 s. L-NAME+INDO (n = 17) reduced the response to 18% and markedly accelerated tmax to 16s (= EDHF). Results were similar for BK with slightly more PG and less NO contribution than for ACh. Constrictor responses to NE and ANG II were augmented and decelerated by L-NAME and L-NAME+INDO. The calculated difference (= buffering by NO or NO+PG) was slower than the constriction. It is concluded that NO, PG, and EDHF contribute >50%, 20-40%, and <20% to the renal vasodilator effect of ACh and BK, respectively. EDHF acts substantially faster and less sustained (tmax = 16 s) than NO and PG (tmax = 30 s). Constrictor buffering by NO and PG is not constant over time, but renders the constriction less sustained.

Evaluation of Water Use Efficiency of Short Rotation Poplar Coppice at Bohemian-Moravian Highlands

NASA Astrophysics Data System (ADS)

Hlaváčová, Marcela; Fischer, Milan; Mani Tripathi, Abhishek; Orság, Matěj; Trnka, Miroslav

2015-04-01

The water availability of the locality constitutes one of the main constraint for short rotation coppices grown on arable land. As a convenient characteristic assessing how the water use is coupled with the biomass yields, so called water use efficiency (WUE) is proposed. One method of water use efficiency determination is presented within this study. The study was carried out at short rotation poplar coppice (poplar clone J-105) at the Test Station Domanínek, Ltd. at Bohemian-Moravian Highlands during the growing season 2013. Diameters at breast height (DBH) were measured for 16 sample trees where sap flow measuring systems (Granier's Thermal Dissipation Probe, TDP) were installed. TDP outputs are expressed as temperature differences (ΔT) between the heated and non-heated probes. Estimation of sap flux density (Fd) by the Granier method relies on the measurement of temperature difference (ΔT). Determination of maximum temperature difference (ΔTmax) is fundamental for sap flux density (Fd) calculation. Although ΔTmax can be theoretically defined as ΔT at Fd = 0, many factors may prevent the occurrence of the zero flow state, such as night-time water movement for new growth (vegetative or reproductive) or water loss from the canopy due to high vapour pressure deficit (VPD). Therefore, the VPD condition was established for determination of ΔTmax. VPD condition was established as follows: VPD reaching values 0.2 at least 6 hours during night (from 21 p. m. to 3 a. m. and when the condition was fullfilled, the value at 3 a. m. was taken) because it is a supposed time after that the tree has no transpiration. The programmable part of Mini 32 software (www.emsbrno.cz) was used for application of the script establishing ΔTmax values under this VPD condition. Nevertheless, another script was applied on ΔT data set to determination of ΔTmax values for every night at 3 a. m. (as this is when ΔT should be at its daily maximum) without VPD condition restriction for comparison of both approaches. Since application of the two mentioned scripts led to two sets of resulting values, calculations of Fd and consequent sap flow values were computed for both variants of ΔTmaxvalues. The sample trees were divided into 3 diameter classes according to DBH values at the beginning of regular measurements (April 24, 2013). Allometry was carried out on February 20, 2014 to calculation of aboveground woody biomass. The input data for calculations of WUE of aboveground woody biomass productivity was biomass increments and monthly totals of sap flow for 16 sample trees. The total WUE for 16 measured trees reached 4.93 g kg-1 (when calculated with data set without VPD condition) and 4.63 g kg-1 (when calculated with data set under VPD condition). This study was funded by project "Building up a multidisciplinary scientific team focused on drought" No. CZ.1.07/2.3.00/20.0248 and LD130030 supporting COST Action ES1106.

Changes of the time-varying percentiles of daily extreme temperature in China

NASA Astrophysics Data System (ADS)

Li, Bin; Chen, Fang; Xu, Feng; Wang, Xinrui

2017-11-01

Identifying the air temperature frequency distributions and evaluating the trends in time-varying percentiles are very important for climate change studies. In order to get a better understanding of the recent temporal and spatial pattern of the temperature changes in China, we have calculated the trends in temporal-varying percentiles of the daily extreme air temperature firstly. Then we divide all the stations to get the spatial patterns for the percentile trends using the average linkage cluster analysis method. To make a comparison, the shifts of trends percentile frequency distribution from 1961-1985 to 1986-2010 are also examined. Important results in three aspects have been achieved: (1) In terms of the trends in temporal-varying percentiles of the daily extreme air temperature, the most intense warming for daily maximum air temperature (Tmax) was detected in the upper percentiles with a significant increasing tendency magnitude (>2.5 °C/50year), and the greatest warming for daily minimum air temperature (Tmin) occurred with very strong trends exceeding 4 °C/50year. (2) The relative coherent spatial patterns for the percentile trends were found, and stations for the whole country had been divided into three clusters. The three primary clusters were distributed regularly to some extent from north to south, indicating the possible large influence of the latitude. (3) The most significant shifts of trends percentile frequency distribution from 1961-1985 to 1986-2010 was found in Tmax. More than half part of the frequency distribution show negative trends less than -0.5 °C/50year in 1961-1985, while showing trends less than 2.5 °C/50year in 1986-2010.

Historical simulations and climate change projections over India by NCAR CCSM4: CMIP5 vs. NEX-GDDP

NASA Astrophysics Data System (ADS)

Sahany, Sandeep; Mishra, Saroj Kanta; Salunke, Popat

2018-03-01

A new bias-corrected statistically downscaled product, namely, the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP), has recently been developed by NASA to help the scientific community in climate change impact studies at local to regional scale. In this work, the product is validated over India and its added value as compared to its CMIP5 counterpart for the NCAR CCSM4 model is analyzed, followed by climate change projections under the RCP8.5 global warming scenario using the two datasets for the variables daily maximum 2-m air temperature (Tmax), daily minimum 2-m air temperature (Tmin), and rainfall. It is found that, overall, the CCSM4-NEX-GDDP significantly reduces many of the biases in CCSM4-CMIP5 for the historical simulations; however, some biases such as the significant overestimation in the frequency of occurrence in the lower tail of the Tmax and Tmin still remain. In regard to rainfall, an important value addition in CCSM4-NEX-GDDP is the alleviation of the significant underestimation of rainfall extremes found in CCSM4-CMIP5. The projected Tmax from CCSM4-NEX-GDDP are in general higher than that projected by CCSM4-CMIP5, suggesting that the risks of heat waves and very hot days could be higher than that projected by the latter. CCSM4-NEX-GDDP projects the frequency of occurrence of the upper extreme values of historical Tmax to increase by a factor of 100 towards the end of century (as opposed to a factor of 10 increase projected by CCSM4-CMIP5). In regard to rainfall, both CCSM4-CMIP5 and CCSM4-NEX-GDDP project an increase in annual rainfall over India under the RCP8.5 global warming scenario progressively from the near term through the far term. However, CCSM4-NEX-GDDP consistently projects a higher magnitude of increase and over a larger area as compared to that projected by CCSM4-CMIP5. Projected daily rainfall distributions from CCSM4-CMIP5 and CCSM4-NEX-GDDP suggest the occurrence of events that have no historical precedents. Worth noting is that the extreme daily rainfall values projected by CCSM4-NEX-GDDP are two to three times larger than that projected by CCSM4-CMIP5.

­Assessing the causes of 20th century wetting in the eastern United States

NASA Astrophysics Data System (ADS)

Bishop, D. A.; Williams, P.; Seager, R.; Fiore, A. M.; Cook, B.; Mankin, J. S.; Singh, D.; Smerdon, J. E.; Rao, M. P.

2017-12-01

During the 20th century, a large area of the eastern United States (US) experienced increases in precipitation and reduced warming, with seasonal cooling of daytime temperatures. These trends are in stark contrast with observed drying and warming globally, particularly with those in the western US. While the reduced temperature trends, termed the eastern US `warming hole,' are well documented and have been linked to reduced insolation from aerosols, evaporative cooling from increased precipitation, and natural climate variability, there is little research evaluating the timing, spatial extent, and physical origins of the historical eastern US precipitation trends. Here we investigate: (1) hydroclimate trends and variability across the continental US for 1895-2016 for all seasons, (2) mechanistic links between wetting and cooling trends in the Southeast US, and (3) dynamical links between wetting trends and large-scale atmospheric circulation changes. Our analyses of hydroclimatic trends indicate strong positive trends in fall precipitation in the Southeast and Northeast US, and positive trends in summer precipitation in the Northeast and Midwest US. The Southeast and Midwest wetting trends are coincident with negative trends in mean daily maximum temperatures (TMax), whereas the Northeast US wetting coincides with warming. Cross-wavelet analysis indicates low-frequency anti-phasing between summer precipitation and TMax, particularly in the Southeast US, but there is little coherence in the fall-season relationship. These results support a positive link between precipitation and evaporative cooling, as this mechanism is expected to be most focused in the boreal summer season. To investigate the shift to wetter conditions in the eastern US, we evaluate moisture transport across multiple reanalysis products, surface observations, and CMIP5 model runs. We find a step-shift toward enhanced southerly flow from the Gulf of Mexico into the Southeast and Midwest US that contributes to the observed wetting in the mid-20th century. Initial results indicate a fall-season westward intensification of the Bermuda High linked with southerly flow over the Southeast US. Further work will be needed to diagnose the dynamical drivers and possible role of anthropogenic forcing.

High-resolution projections of 21st century climate over the Athabasca River Basin through an integrated evaluation-classification-downscaling-based climate projection framework

NASA Astrophysics Data System (ADS)

Cheng, Guanhui; Huang, Guohe; Dong, Cong; Zhu, Jinxin; Zhou, Xiong; Yao, Y.

2017-03-01

An evaluation-classification-downscaling-based climate projection (ECDoCP) framework is developed to fill a methodological gap of general circulation models (GCMs)-driven statistical-downscaling-based climate projections. ECDoCP includes four interconnected modules: GCM evaluation, climate classification, statistical downscaling, and climate projection. Monthly averages of daily minimum (Tmin) and maximum (Tmax) temperature and daily cumulative precipitation (Prec) over the Athabasca River Basin (ARB) at a 10 km resolution in the 21st century under four Representative Concentration Pathways (RCPs) are projected through ECDoCP. At the octodecadal scale, temperature and precipitation would increase; after bias correction, temperature would increase with a decreased increment, while precipitation would increase only under RCP 8.5. Interannual variability of climate anomalies would increase from RCPs 4.5, 2.6, 6.0 to 8.5 for temperature and from RCPs 2.6, 4.5, 6.0 to 8.5 for precipitation. Bidecadal averaged climate anomalies would decrease from December-January-February (DJF), March-April-May (MAM), September-October-November (SON) to June-July-August (JJA) for Tmin, from DJF, SON, MAM to JJA for Tmax, and from JJA, MAM, SON to DJF for Prec. Climate projection uncertainties would decrease in May to September for temperature and in November to April for precipitation. Spatial climatic variability would not obviously change with RCPs; climatic anomalies are highly correlated with climate-variable magnitudes. Climate anomalies would decrease from upstream to downstream for temperature, and precipitation would follow an opposite pattern. The north end and the other zones would have colder and warmer days, respectively; precipitation would decrease in the upstream and increase in the remaining region. Climate changes might lead to issues, e.g., accelerated glacier/snow melting, deserving attentions of researchers and the public.

Spatial and seasonal patterns in climate change, temperatures, and precipitation across the United States.

PubMed

Portmann, Robert W; Solomon, Susan; Hegerl, Gabriele C

2009-05-05

Changes in climate during the 20th century differ from region to region across the United States. We provide strong evidence that spatial variations in US temperature trends are linked to the hydrologic cycle, and we also present unique information on the seasonal and latitudinal structure of the linkage. We show that there is a statistically significant inverse relationship between trends in daily temperature and average daily precipitation across regions. This linkage is most pronounced in the southern United States (30-40 degrees N) during the May-June time period and, to a lesser extent, in the northern United States (40-50 degrees N) during the July-August time period. It is strongest in trends in maximum temperatures (T(max)) and 90th percentile exceedance trends (90PET), and less pronounced in the T(max) 10PET and the corresponding T(min) statistics, and it is robust to changes in analysis period. Although previous studies suggest that areas of increased precipitation may have reduced trends in temperature compared with drier regions, a change in sign from positive to negative trends suggests some additional cause. We show that trends in precipitation may account for some, but not likely all, of the cause point to evidence that shows that dynamical patterns (El Niño/Southern Oscillation, North Atlantic Oscillation, etc.) cannot account for the observed effects during May-June. We speculate that changing aerosols, perhaps related to vegetation changes, and increased strength of the aerosol direct and indirect effect may play a role in the observed linkages between these indices of temperature change and the hydrologic cycle.

Exploring the association between heat and mortality in Switzerland between 1995 and 2013.

PubMed

Ragettli, Martina S; Vicedo-Cabrera, Ana M; Schindler, Christian; Röösli, Martin

2017-10-01

Designing effective public health strategies to prevent adverse health effect of hot weather is crucial in the context of global warming. In Switzerland, the 2003 heat have caused an estimated 7% increase in all-cause mortality. As a consequence, the Swiss Federal Office of Public Health developed an information campaign to raise public awareness on heat threats. For a better understanding on how hot weather affects daily mortality in Switzerland, we assessed the effect of heat on daily mortality in eight Swiss cities and population subgroups from 1995 to 2013 using different temperature metrics (daily mean (Tmean), maximum (Tmax), minimum (Tmin) and maximum apparent temperature (Tappmax)), and aimed to evaluate variations of the heat effect after 2003 (1995-2002 versus 2004-2013). We applied conditional quasi-Poisson regression models with non-linear distributed lag functions to estimate temperature-mortality associations over all cities (1995-2013) and separately for two time periods (1995-2002, 2004-2013). Relative risks (RR) of daily mortality were estimated for increases in temperature from the median to the 98th percentile of the warm season temperature distribution. Over the whole time period, significant temperature-mortality relationships were found for all temperature indicators (RR (95% confidence interval): Tappmax: 1.12 (1.05; 1.18); Tmax: 1.15 (1.08-1.22); Tmean: 1.16 (1.09-1.23); Tmin 1.23 (1.15-1.32)). Mortality risks were higher at the beginning of the summer, especially for Tmin. In the more recent time period, we observed a non-significant reduction in the effect of high temperatures on mortality, with the age group > 74 years remaining the population at highest risk. High temperatures continue to be a considerable risk factor for human health in Switzerland after 2003. More effective public health measures targeting the elderly should be promoted with increased attention to the first heat events in summer and considering both high day-time and night-time temperatures. Copyright © 2017 Elsevier Inc. All rights reserved.

Improving medium-range and seasonal hydroclimate forecasts in the southeast USA

NASA Astrophysics Data System (ADS)

Tian, Di

Accurate hydro-climate forecasts are important for decision making by water managers, agricultural producers, and other stake holders. Numerical weather prediction models and general circulation models may have potential for improving hydro-climate forecasts at different scales. In this study, forecast analogs of the Global Forecast System (GFS) and Global Ensemble Forecast System (GEFS) based on different approaches were evaluated for medium-range reference evapotranspiration (ETo), irrigation scheduling, and urban water demand forecasts in the southeast United States; the Climate Forecast System version 2 (CFSv2) and the North American national multi-model ensemble (NMME) were statistically downscaled for seasonal forecasts of ETo, precipitation (P) and 2-m temperature (T2M) at the regional level. The GFS mean temperature (Tmean), relative humidity, and wind speed (Wind) reforecasts combined with the climatology of Reanalysis 2 solar radiation (Rs) produced higher skill than using the direct GFS output only. Constructed analogs showed slightly higher skill than natural analogs for deterministic forecasts. Both irrigation scheduling driven by the GEFS-based ETo forecasts and GEFS-based ETo forecast skill were generally positive up to one week throughout the year. The GEFS improved ETo forecast skill compared to the GFS. The GEFS-based analog forecasts for the input variables of an operational urban water demand model were skillful when applied in the Tampa Bay area. The modified operational models driven by GEFS analog forecasts showed higher forecast skill than the operational model based on persistence. The results for CFSv2 seasonal forecasts showed maximum temperature (Tmax) and Rs had the greatest influence on ETo. The downscaled Tmax showed the highest predictability, followed by Tmean, Tmin, Rs, and Wind. The CFSv2 model could better predict ETo in cold seasons during El Nino Southern Oscillation (ENSO) events only when the forecast initial condition was in ENSO. Downscaled P and T2M forecasts were produced by directly downscaling the NMME P and T2M output or indirectly using the NMME forecasts of Nino3.4 sea surface temperatures to predict local-scale P and T2M. The indirect method generally showed the highest forecast skill which occurs in cold seasons. The bias-corrected NMME ensemble forecast skill did not outperform the best single model.

Shrinking windows of opportunity for oak seedling establishment in southern California mountains

USGS Publications Warehouse

Davis, Frank W.; Sweet, Lynn C.; Serra-Diaz, Josep M.; Franklin, Janet; McCullough, Ian M.; Flint, Alan L.; Flint, Lorraine E.; Dingman, John; Regan, Helen M.; Syphard, Alexandra D.; Hannah, Lee; Redmond, Kelly; Moritz, Max A.

2016-01-01

Seedling establishment is a critical step that may ultimately govern tree species’ distribution shifts under environmental change. Annual variation in the location of seed rain and microclimates results in transient “windows of opportunity” for tree seedling establishment across the landscape. These establishment windows vary at fine spatiotemporal scales that are not considered in most assessments of climate change impacts on tree species range dynamics and habitat displacement. We integrate field seedling establishment trials conducted in the southern Sierra Nevada and western Tehachapi Mountains of southern California with spatially downscaled grids of modeled water-year climatic water deficit (CWDwy) and mean August maximum daily temperature (Tmax) to map historical and projected future microclimates suitable for establishment windows of opportunity for Quercus douglasii, a dominant tree species of warm, dry foothill woodlands, and Q. kelloggii, a dominant of cooler, more mesic montane woodlands and forests. Based on quasi-binomial regression models, Q. douglasii seedling establishment is significantly associated with modeled CWDwy and to a lesser degree with modeled Tmax. Q. kelloggii seedling establishment is most strongly associated with Tmax and best predicted by a two-factor model including CWDwy and Tmax. Establishment niche models are applied to explore recruitment window dynamics in the western Tehachapi Mountains, where these species are currently widespread canopy dominants. Establishment windows are projected to decrease by 50–95%, shrinking locally to higher elevations and north-facing slopes by the end of this century depending on the species and climate scenario. These decreases in establishment windows suggest the potential for longer-term regional population declines of the species. While many additional processes regulate seedling establishment and growth, this study highlights the need to account for topoclimatic controls and interannual climatic variation when assessing how seedling establishment and colonization processes could be affected by climate change.

Heat waves over Central Europe in regional climate model simulations

NASA Astrophysics Data System (ADS)

Lhotka, Ondřej; Kyselý, Jan

2014-05-01

Regional climate models (RCMs) have become a powerful tool for exploring impacts of global climate change on a regional scale. The aim of the study is to evaluate the capability of RCMs to reproduce characteristics of major heat waves over Central Europe in their simulations of the recent climate (1961-2000), with a focus on the most severe and longest Central European heat wave that occurred in 1994. We analyzed 7 RCM simulations with a high resolution (0.22°) from the ENSEMBLES project, driven by the ERA-40 reanalysis. In observed data (the E-OBS 9.0 dataset), heat waves were defined on the basis of deviations of daily maximum temperature (Tmax) from the 95% quantile of summer Tmax distribution in grid points over Central Europe. The same methodology was applied in the RCM simulations; we used corresponding 95% quantiles (calculated for each RCM and grid point) in order to remove the bias of modelled Tmax. While climatological characteristics of heat waves are reproduced reasonably well in the RCM ensemble, we found major deficiencies in simulating heat waves in individual years. For example, METNOHIRHAM simulated very severe heat waves in 1996, when no heat wave was observed. Focusing on the major 1994 heat wave, considerable differences in simulated temperature patterns were found among the RCMs. The differences in the temperature patterns were clearly linked to the simulated amount of precipitation during this event. The 1994 heat wave was almost absent in all RCMs that did not capture the observed precipitation deficit, while it was by far most pronounced in KNMI-RACMO that simulated virtually no precipitation over Central Europe during the 15-day period of the heat wave. By contrast to precipitation, values of evaporative fraction in the RCMs were not linked to severity of the simulated 1994 heat wave. This suggests a possible major contribution of other factors such as cloud cover and associated downward shortwave radiation. Therefore, a more detailed analysis of individual components of the energy budget over Central Europe during and before the 1994 heat wave was performed.

Analyzing the future climate change of Upper Blue Nile River basin using statistical downscaling techniques

NASA Astrophysics Data System (ADS)

Fenta Mekonnen, Dagnenet; Disse, Markus

2018-04-01

Climate change is becoming one of the most threatening issues for the world today in terms of its global context and its response to environmental and socioeconomic drivers. However, large uncertainties between different general circulation models (GCMs) and coarse spatial resolutions make it difficult to use the outputs of GCMs directly, especially for sustainable water management at regional scale, which introduces the need for downscaling techniques using a multimodel approach. This study aims (i) to evaluate the comparative performance of two widely used statistical downscaling techniques, namely the Long Ashton Research Station Weather Generator (LARS-WG) and the Statistical Downscaling Model (SDSM), and (ii) to downscale future climate scenarios of precipitation, maximum temperature (Tmax) and minimum temperature (Tmin) of the Upper Blue Nile River basin at finer spatial and temporal scales to suit further hydrological impact studies. The calibration and validation result illustrates that both downscaling techniques (LARS-WG and SDSM) have shown comparable and good ability to simulate the current local climate variables. Further quantitative and qualitative comparative performance evaluation was done by equally weighted and varying weights of statistical indexes for precipitation only. The evaluation result showed that SDSM using the canESM2 CMIP5 GCM was able to reproduce more accurate long-term mean monthly precipitation but LARS-WG performed best in capturing the extreme events and distribution of daily precipitation in the whole data range. Six selected multimodel CMIP3 GCMs, namely HadCM3, GFDL-CM2.1, ECHAM5-OM, CCSM3, MRI-CGCM2.3.2 and CSIRO-MK3 GCMs, were used for downscaling climate scenarios by the LARS-WG model. The result from the ensemble mean of the six GCM showed an increasing trend for precipitation, Tmax and Tmin. The relative change in precipitation ranged from 1.0 to 14.4 % while the change for mean annual Tmax may increase from 0.4 to 4.3 °C and the change for mean annual Tmin may increase from 0.3 to 4.1 °C. The individual result of the HadCM3 GCM has a good agreement with the ensemble mean result. HadCM3 from CMIP3 using A2a and B2a scenarios and canESM2 from CMIP5 GCMs under RCP2.6, RCP4.5 and RCP8.5 scenarios were downscaled by SDSM. The result from the two GCMs under five different scenarios agrees with the increasing direction of three climate variables (precipitation, Tmax and Tmin). The relative change of the downscaled mean annual precipitation ranges from 2.1 to 43.8 % while the change for mean annual Tmax and Tmin may increase in the range from 0.4 to 2.9 °C and from 0.3 to 1.6 °C respectively.

Long-term patterns of air temperatures, daily temperature range, precipitation, grass-reference evapotranspiration and aridity index in the USA great plains: Part II. Temporal trends

NASA Astrophysics Data System (ADS)

Kukal, M.; Irmak, S.

2016-11-01

Detection of long-term changes in climate variables over large spatial scales is a very important prerequisite to the development of effective mitigation and adaptation measures for the future potential climate change and for developing strategies for future hydrologic balance analyses under changing climate. Moreover, there is a need for effective approaches of providing information about these changes to decision makers, water managers and stakeholders to aid in efficient implementation of the developed strategies. This study involves computation, mapping and analyses of long-term (1968-2013) county-specific trends in annual, growing-season (1st May-30th September) and monthly air temperatures [(maximum (Tmax), minimum (Tmin) and average (Tavg)], daily temperature range (DTR), precipitation, grass reference evapotranspiration (ETo) and aridity index (AI) over the USA Great Plains region using datasets from over 800 weather station sites. Positive trends in annual Tavg, Tmax and Tmin, DTR, precipitation, ETo and AI were observed in 71%, 89%, 85%, 31%, 61%, 38% and 66% of the counties in the region, respectively, whereas these proportions were 48%, 89%, 62%, 20%, 57%, 28%, and 63%, respectively, for the growing-season averages of the same variables. On a regional average basis, the positive trends in growing-season Tavg, Tmax and Tmin, DTR, precipitation, ETo and AI were 0.18 °C decade-1, 0.19 °C decade-1, 0.17 °C decade-1, 0.09 °C decade-1, 1.12 mm yr-1, 0.4 mm yr-1 and 0.02 decade-1, respectively, and the negative trends were 0.21 °C decade-1, 0.06 °C decade-1, 0.09 °C decade-1, 0.22 °C decade-1, 1.16 mm yr-1, 0.76 mm yr-1 and 0.02 decade-1, respectively. The temporal trends were highly variable in space and were appropriately represented using monthly, annual and growing-season maps developed using Geographic Information System (GIS) techniques. The long-term and spatial and temporal information and data for a large region provided in this study can be used to analyze county-level trends in important climatic/hydrologic variables in context of climate change, water resources, agricultural and natural resources response to climate change.

Assessment of Air Temperature Trends in the Source Region of Yellow River and Its Sub-Basins, China

NASA Astrophysics Data System (ADS)

Iqbal, Mudassar; Wen, Jun; Wang, Xin; Lan, Yongchao; Tian, Hui; Anjum, Muhammad Naveed; Adnan, Muhammad

2018-02-01

Changes in climatic variables at the sub-basins scale (having different features of land cover) are crucial for planning, development and designing of water resources infrastructure in the context of climate change. Accordingly, to explore the features of climate changes in sub-basins of the Source Region of Yellow River (SRYR), absolute changes and trends of temperature variables, maximum temperature (Tmax), minimum temperature (Tmin), mean temperature (Tavg) and diurnal temperature range (DTR), were analyzed annually and seasonally by using daily observed air temperature dataset from 1965 to 2014. Results showed that annual Tmax, Tmin and Tavg for the SRYR were experiencing warming trends respectively at the rate of 0.28, 0.36 and 0.31°C (10 yr)-1. In comparison with the 1st period (1965-1989), more absolute changes and trends towards increasing were observed during the 2nd period (1990-2014). Apart from Tangnaihai (a low altitude sub-basin), these increasing trends and changes seemed more significant in other basins with highest magnitude during winter. Among sub-basins the increasing trends were more dominant in Huangheyan compared to other sub-basins. The largest increase magnitude of Tmin, 1.24 and 1.18°C (10 yr)-1, occurred in high altitude sub-basins Jimai and Huangheyan, respectively, while the smallest increase magnitude of 0.23°C (10 yr)-1 occurred in a low altitude sub-basin Tangnaihai. The high elevation difference in Tangnaihai probably was the main reason for the less increase in the magnitude of Tmin. In the last decade, smaller magnitude of trend for all temperature variables signified the signal of cooling in the region. Overall, changes of temperature variables had significant spatial and seasonal variations. It implies that seasonal variations of runoff might be greater or different for each sub-basin.

Heat-related illness in Washington State agriculture and forestry sectors.

PubMed

Spector, June T; Krenz, Jennifer; Rauser, Edmund; Bonauto, David K

2014-08-01

We sought to describe heat-related illness (HRI) in agriculture and forestry workers in Washington State. Demographic and clinical Washington State Fund workers' compensation agriculture and forestry HRI claims data (1995-2009) and Washington Agriculture Heat Rule citations (2009-2012) were accessed and described. Maximum daily temperature (Tmax) and Heat Index (HImax) were estimated by claim date and location using AgWeatherNet's weather station network. There were 84 Washington State Fund agriculture and forestry HRI claims and 60 Heat Rule citations during the study period. HRI claims and citations were most common in crop production and support subsectors. The mean Tmax (HImax) was 95°F (99°F) for outdoor HRI claims. Potential HRI risk factors and HRI-related injuries were documented for some claims. Agriculture and forestry HRI cases are characterized by potential work-related, environmental, and personal risk factors. Further work is needed to elucidate the relationship between heat exposure and occupational injuries. © 2014 Wiley Periodicals, Inc.

An approach to get thermodynamic properties from speed of sound

NASA Astrophysics Data System (ADS)

Núñez, M. A.; Medina, L. A.

2017-01-01

An approach for estimating thermodynamic properties of gases from the speed of sound u, is proposed. The square u2, the compression factor Z and the molar heat capacity at constant volume C V are connected by two coupled nonlinear partial differential equations. Previous approaches to solving this system differ in the conditions used on the range of temperature values [Tmin,Tmax]. In this work we propose the use of Dirichlet boundary conditions at Tmin, Tmax. The virial series of the compression factor Z = 1+Bρ+Cρ2+… and other properties leads the problem to the solution of a recursive set of linear ordinary differential equations for the B, C. Analytic solutions of the B equation for Argon are used to study the stability of our approach and previous ones under perturbation errors of the input data. The results show that the approach yields B with a relative error bounded basically by that of the boundary values and the error of other approaches can be some orders of magnitude lager.

Heat-Related Illness in Washington State Agriculture and Forestry Sectors

PubMed Central

Spector, June T.; Krenz, Jennifer; Rauser, Edmund; Bonauto, David K.

2017-01-01

Background We sought to describe heat-related illness (HRI) in agriculture and forestry workers in Washington State. Methods Demographic and clinical Washington State Fund workers’ compensation agriculture and forestry HRI claims data (1995–2009) and Washington Agriculture Heat Rule citations (2009–2012) were accessed and described. Maximum daily temperature (Tmax) and Heat Index (HImax) were estimated by claim date and location using AgWeatherNet’s weather station network. Results There were 84 Washington State Fund agriculture and forestry HRI claims and 60 Heat Rule citations during the study period. HRI claims and citations were most common in crop production and support subsectors. The mean Tmax (HImax) was 95°F (99°F) for outdoor HRI claims. Potential HRI risk factors and HRI-related injuries were documented for some claims. Conclusions Agriculture and forestry HRI cases are characterized by potential work-related, environmental, and personal risk factors. Further work is needed to elucidate the relationship between heat exposure and occupational injuries. PMID:24953344

Vastus lateralis single motor unit EMG at the same absolute torque production at different knee angles.

PubMed

Altenburg, T M; de Haan, A; Verdijk, P W L; van Mechelen, W; de Ruiter, C J

2009-07-01

Single motor unit electromyographic (EMG) activity of the knee extensors was investigated at different knee angles with subjects (n = 10) exerting the same absolute submaximal isometric torque at each angle. Measurements were made over a 20 degrees range around the optimum angle for torque production (AngleTmax) and, where feasible, over a wider range (50 degrees ). Forty-six vastus lateralis (VL) motor units were recorded at 20.7 +/- 17.9 %maximum voluntary contraction (%MVC) together with the rectified surface EMG (rsEMG) of the superficial VL muscle. Due to the lower maximal torque capacity at positions more flexed and extended than AngleTmax, single motor unit recruitment thresholds were expected to decrease and discharge rates were expected to increase at angles above and below AngleTmax. Unexpectedly, the recruitment threshold was higher (P < 0.05) at knee angles 10 degrees more extended (43.7 +/- 22.2 N.m) and not different (P > 0.05) at knee angles 10 degrees more flexed (35.2 +/- 17.9 N.m) compared with recruitment threshold at AngleTmax (41.8 +/- 21.4 N.m). Also, unexpectedly the discharge rates were similar (P > 0.05) at the three angles: 11.6 +/- 2.2, 11.6 +/- 2.1, and 12.3 +/- 2.1 Hz. Similar angle independent discharge rates were also found for 12 units (n = 5; 7.4 +/- 5.4 %MVC) studied over the wider (50 degrees ) range, while recruitment threshold only decreased at more flexed angles. In conclusion, the similar recruitment threshold and discharge behavior of VL motor units during submaximal isometric torque production suggests that net motor unit activation did not change very much along the ascending limb of the knee-angle torque relationship. Several factors such as length-dependent twitch potentiation, which may contribute to this unexpected aspect of motor control, are discussed.

Seasonal divergence in the interannual responses of Northern Hemisphere vegetation activity to variations in diurnal climate.

PubMed

Wu, Xiuchen; Liu, Hongyan; Li, Xiaoyan; Liang, Eryuan; Beck, Pieter S A; Huang, Yongmei

2016-01-11

Seasonal asymmetry in the interannual variations in the daytime and nighttime climate in the Northern Hemisphere (NH) is well documented, but its consequences for vegetation activity remain poorly understood. Here, we investigate the interannual responses of vegetation activity to variations of seasonal mean daytime and nighttime climate in NH (>30 °N) during the past decades using remote sensing retrievals, FLUXNET and tree ring data. Despite a generally significant and positive response of vegetation activity to seasonal mean maximum temperature (Tmax) in ~22-25% of the boreal (>50 °N) NH between spring and autumn, spring-summer progressive water limitations appear to decouple vegetation activity from the mean summer Tmax, particularly in climate zones with dry summers. Drought alleviation during autumn results in vegetation recovery from the marked warming-induced drought limitations observed in spring and summer across 24-26% of the temperate NH. Vegetation activity exhibits a pervasively negative correlation with the autumn mean minimum temperature, which is in contrast to the ambiguous patterns observed in spring and summer. Our findings provide new insights into how seasonal asymmetry in the interannual variations in the mean daytime and nighttime climate interacts with water limitations to produce spatiotemporally variable responses of vegetation growth.

Quantifying the effect of Tmax extreme events on local adaptation to climate change of maize crop in Andalusia for the 21st century

NASA Astrophysics Data System (ADS)

Gabaldon, Clara; Lorite, Ignacio J.; Ines Minguez, M.; Lizaso, Jon; Dosio, Alessandro; Sanchez, Enrique; Ruiz-Ramos, Margarita

2015-04-01

Extreme events of Tmax can threaten maize production on Andalusia (Ruiz-Ramos et al., 2011). The objective of this work is to attempt a quantification of the effects of Tmax extreme events on the previously identified (Gabaldón et al., 2013) local adaptation strategies to climate change of irrigated maize crop in Andalusia for the first half of the 21st century. This study is focused on five Andalusia locations. Local adaptation strategies identified consisted on combinations of changes on sowing dates and choice of cultivar (Gabaldón et al., 2013). Modified cultivar features were the duration of phenological phases and the grain filling rate. The phenological and yield simulations with the adaptative changes were obtained from a modelling chain: current simulated climate and future climate scenarios (2013-2050) were taken from a group of regional climate models at high resolution (25 km) from the European Project ENSEMBLES (http://www.ensembles-eu.org/). After bias correcting these data for temperature and precipitation (Dosio and Paruolo, 2011; Dosio et al., 2012) crop simulations were generated by the CERES-maize model (Jones and Kiniry, 1986) under DSSAT platform, previously calibrated and validated. Quantification of the effects of extreme Tmax on maize yield was computed for different phenological stages following Teixeira et al. (2013). A heat stress index was computed; this index assumes that yield-damage intensity due to heat stress increases linearly from 0.0 at a critical temperature to a maximum of 1.0 at a limit temperature. The decrease of crop yield is then computed by a normalized production damage index which combines attainable yield and heat stress index for each location. Selection of the most suitable adaptation strategy will be reviewed and discussed in light of the quantified effect on crop yield of the projected change of Tmax extreme events. This study will contribute to MACSUR knowledge Hub within the Joint Programming Initiative on Agriculture, Food Security and Climate Change (FACCE - JPI) of EU and is financed by MULCLIVAR project (CGL2012-38923-C02-02) and IFAPA project AGR6126 from Junta de Andalucía, Spain. References Dosio A. and Paruolo P., 2011. Bias correction of the ENSEMBLES high-resolution climate change projections for use by impact models: Evaluation on the present climate. Journal of Geophysical Research, VOL. 116, D16106, doi:10.1029/2011JD015934 Dosio A., Paruolo P. and Rojas R., 2012. Bias correction of the ENSEMBLES high resolution climate change projections for use by impact models: Analysis of the climate change signal. Journal of Geophysical Research, Volume 117, D17, doi: 0.1029/2012JD017968 Gabaldón C, Lorite IJ, Mínguez MI, Dosio A, Sánchez-Sánchez E and Ruiz-Ramos M, 2013. Evaluation of local adaptation strategies to climate change of maize crop in Andalusia for the first half of 21st century. Geophysical Research Abstracts. Vol. 15, EGU2013-13625, 2013. EGU General Assembly 2013, April 2013, Vienna, Austria. Jones C.A. and J.R. Kiniry. 1986. CERES-Maize: A simulation model of maize growth and development. Texas A&M Univ. Press, College Station. Ruiz-Ramos M., E. Sanchez, C. Galllardo, and M.I. Minguez. 2011. Impacts of projected maximum temperature extremes for C21 by an ensemble of regional climate models on cereal cropping systems in the Iberian Peninsula. Natural Hazards and Earth System Science 11: 3275-3291. Teixeira EI, Fischer G, van Velthuizen H, Walter C, Ewert F. Global hotspots of heat stress on agricultural crops due to climate change. Agric For Meteorol. 2013;170(15):206-215.

Tables of the Inverse Laplace Transform of the Function e−sβ

PubMed Central

Dishon, Menachem; Bendler, John T.; Weiss, George H.

1990-01-01

The inverse transform, g(t)=L−1(e−sβ), 0 < β < 1, is a stable law that arises in a number of different applications in chemical physics, polymer physics, solid-state physics, and applied mathematics. Because of its important applications, a number of investigators have suggested approximations to g(t). However, there have so far been no accurately calculated values available for checking or other purposes. We present here tables, accurate to six figures, of g(t) for a number of values of β between 0.25 and 0.999. In addition, since g(t), regarded as a function of β, is uni-modal with a peak occurring at t = tmax we both tabulate and graph tmax and 1/g(tmax) as a function of β, as well as giving polynomial approximations to 1/g(tmax). PMID:28179785

Characterizing Air Temperature Changes in the Tarim Basin over 1960–2012

PubMed Central

Peng, Dongmei; Wang, Xiujun; Zhao, Chenyi; Wu, Xingren; Jiang, Fengqing; Chen, Pengxiang

2014-01-01

There has been evidence of warming rate varying largely over space and between seasons. However, little has been done to evaluate the spatial and temporal variability of air temperature in the Tarim Basin, northwest China. In this study, we collected daily air temperature from 19 meteorological stations for the period of 1960–2012, and analyzed annual mean temperature (AMT), the annual minimum (Tmin) and maximum temperature (Tmax), and mean temperatures of all twelve months and four seasons and their anomalies. Trend analyses, standard deviation of the detrended anomaly (SDDA) and correlations were carried out to characterize the spatial and temporal variability of various mean air temperatures. Our data showed that increasing trend was much greater in the Tmin (0.55°C/10a) than in the AMT (0.25°C/10a) and Tmax (0.12°C/10a), and the fluctuation followed the same order. There were large spatial variations in the increasing trends of both AMT (from −0.09 to 0.43 °C/10a) and Tmin (from 0.15 to 1.12°C/10a). Correlation analyses indicated that AMT had a significantly linear relationship with Tmin and the mean temperatures of four seasons. There were also pronounced changes in the monthly air temperature from November to March at decadal time scale. The seasonality (i.e., summer and winter difference) of air temperature was stronger during the period of 1960–1979 than over the recent three decades. Our preliminary analyses indicated that local environmental conditions (such as elevation) might be partly responsible for the spatial variability, and large scale climate phenomena might have influences on the temporal variability of air temperature in the Tarim Basin. In particular, there was a significant correlation between index of El Niño-Southern Oscillation (ENSO) and air temperature of May (P = 0.004), and between the index of Pacific Decadal Oscillation (PDO) and air temperature of July (P = 0.026) over the interannual to decadal time scales. PMID:25375648

Interplay of antiferromagnetism and Kondo effect in (Ce1-xLax) 8Pd24 Al

NASA Astrophysics Data System (ADS)

Bashir, A. K.; Tchoula Tchokonté, M. B.; Britz, D.; Strydom, A. M.; Kaczorowski, D.

2017-07-01

The interplay of antiferromagnetic (AFM) and Kondo effect in Ce8Pd24 Al with the dilution of Ce with La is investigated by means of electrical and thermal transport and magnetic properties measurements. X - ray diffraction studies confirm a cubic AuCu3 - type crystal structure with space group Pm 3 bar m for all compositions in the alloy series (Ce1-xLax) 8Pd24 Al (0 ≤ x ≤ 1) . Electrical resistivity, ρ (T) results show evolution from coherent Kondo lattice scattering with a well defined Kondo peak at Tmax to incoherent single-ion Kondo scattering with increasing La content x. Magnetoresistivity MR measurements on Ce dilute alloys are negative and analyzed based on the calculations by Schlottmann for the Bethe - ansatz in the framework of the Coqblin - Schrieffer model and yield values of the Kondo temperature TK and the effective moment of the Kondo ion μK. The decrease of Tmax and TK is described by the compressible Kondo lattice model. The thermoelectric power, S(T) measurements are interpreted within the phenomenological resonance model. The Lorentz number, L /L0 increases rapidly on cooling the samples and reaches a maximum value around 6 K. The magnetic susceptibility, χ (T) data at high temperature follow the Curie - Weiss behaviour and yield effective magnetic moments, μeff values across the series close to the value of 2.54 μB expected for the free Ce3+ - ion. The low temperature χ (T) shows an AFM anomaly associated with a Néel temperature TN for alloys in the range 0 ≤ x ≤ 0.2 . No metamagnetic transition was observed from the magnetization results, M (μ0 H) .

Global Warming and Geographically Scalar Climatic Objects Exist: An Ontologically Realist and Object-Oriented Analysis of the Daymet TMAX Climate Summaries for North America

NASA Astrophysics Data System (ADS)

Jackson, C. P.

2017-12-01

The scientific materialist worldview, what Peter Unger refers to as the Scientiphical worldview, or Scientiphicalism, has been utterly catastrophic for mesoscale objects in general, but, with its closely associated twentieth-century formal logic, this has been especially true for notoriously vague things like climate change, coastlines, mountains and dust storms. That is, any so-called representations or references ultimately suffer the same ontological demise as their referents, no matter how well-defined their boundaries may in fact be. Against this reductionist metaphysics, climatic objects are discretized within three separate ontologically realist systems, Graham Harman's object-oriented philosophy, or ontology (OOO), Markus Gabriel's ontology of fields of sense (OFS) and Tristan Garcia's two systems and new order of time, so as to make an ontological case for any geographically scalar object, beginning with pixels, as well as any notoriously vague thing they are said to represent. Four-month overlapping TMAX seasonals were first developed from the Oak Ridge National Laboratory (ORNL) Daymet climate temperature maximum (TMAX) monthly summaries (1980-2016) for North America and segmented within Trimble's eCognition Developer using the simple and widely familiar quadtree algorithm with a scale parameter of four, in this example. The regression coefficient was then calculated for the resulting 37-year climatic objects and an equally simple classification was applied. The same segmentation and classification was applied to the Daymet annual summaries, as well, for comparison. As was expected, the mean warming and cooling trends are lowest for the annual summary TMAX climatic objects. However, the Fall (SOND) season has the largest and smallest areas of warming and cooling, respectively, and the highest mean trend for warming objects. Conversely, Spring (MAMJ) has the largest and smallest areas undergoing cooling and warming, respectively. Finally, Summer (JJAS) has the highest mean trend for cooling objects. Not only do these highly heterogeneous and variable patterns become readily apparent with each set of objects, but so do any possible anomalies that might warrant further investigation.

Probes for investigating the effect of magnetic field, field orientation, temperature and strain on the critical current density of anisotropic high-temperature superconducting tapes in a split-pair 15 T horizontal magnet.

PubMed

Sunwong, P; Higgins, J S; Hampshire, D P

2014-06-01

We present the designs of probes for making critical current density (Jc) measurements on anisotropic high-temperature superconducting tapes as a function of field, field orientation, temperature and strain in our 40 mm bore, split-pair 15 T horizontal magnet. Emphasis is placed on the design of three components: the vapour-cooled current leads, the variable temperature enclosure, and the springboard-shaped bending beam sample holder. The vapour-cooled brass critical-current leads used superconducting tapes and in operation ran hot with a duty cycle (D) of ~0.2. This work provides formulae for optimising cryogenic consumption and calculating cryogenic boil-off, associated with current leads used to make J(c) measurements, made by uniformly ramping the current up to a maximum current (I(max)) and then reducing the current very quickly to zero. They include consideration of the effects of duty cycle, static helium boil-off from the magnet and Dewar (b'), and the maximum safe temperature for the critical-current leads (T(max)). Our optimized critical-current leads have a boil-off that is about 30% less than leads optimized for magnet operation at the same maximum current. Numerical calculations show that the optimum cross-sectional area (A) for each current lead can be parameterized by LI(max)/A = [1.46D(-0.18)L(0.4)(T(max) - 300)(0.25D(-0.09)) + 750(b'/I(max))D(10(-3)I(max)-2.87b') × 10⁶ A m⁻¹ where L is the current lead's length and the current lead is operated in liquid helium. An optimum A of 132 mm(2) is obtained when I(max) = 1000 A, T(max) = 400 K, D = 0.2, b' = 0.3 l h(-1) and L = 1.0 m. The optimized helium consumption was found to be 0.7 l h(-1). When the static boil-off is small, optimized leads have a boil-off that can be roughly parameterized by: b/I(max)  ≈ (1.35 × 10(-3))D(0.41) l h(‑1) A(-1). A split-current-lead design is employed to minimize the rotation of the probes during the high current measurements in our high-field horizontal magnet. The variable-temperature system is based on the use of an inverted insulating cup that operates above 4.2 K in liquid helium and above 77.4 K in liquid nitrogen, with a stability of ±80 mK to ±150 mK. Uniaxial strains of -1.4% to 1.0% can be applied to the sample, with a total uncertainty of better than ±0.02%, using a modified bending beam apparatus which includes a copper beryllium springboard-shaped sample holder.

Ultrasound assessment of diaphragmatic function in patients with amyotrophic lateral sclerosis.

PubMed

Fantini, Riccardo; Mandrioli, Jessica; Zona, Stefano; Antenora, Federico; Iattoni, Andrea; Monelli, Marco; Fini, Nicola; Tonelli, Roberto; Clini, Enrico; Marchioni, Alessandro

2016-07-01

Evaluation of diaphragm function in Amyotrophic Lateral Sclerosis (ALS) is critical in determining when to commence non-invasive mechanical ventilation (NIV). Currently, forced vital capacity (FVC) and sniff nasal inspiratory pressure (SNIP) are volitional measures for this evaluation, but require collaboration and are poorly specific. The primary aim of this study was to assess whether diaphragmatic thickness measured by ultrasound (US) correlates with lung function impairment in ALS patients. The secondary aim was then to compare US diaphragm thickness index (ΔTdi) with a new parameter (ΔTmax index). 41 patients with ALS and 30 healthy subjects were enrolled in the study. All subjects underwent spirometry, SNIP and diaphragm US evaluation, while arterial blood gases were measured in some patients only. US assessed diaphragm thickness (Tdi) at tidal volume (Vt) or total lung capacity (TLC), and their ratio (ΔTmax) were recorded. Changes (Δ) in Tdi indices during tidal volume (ΔTdiVt) and maximal inspiration (ΔTdiTLC) were also assessed. ΔTdiTLC (p <0.001) and ΔTmax (p = 0.007), but not ΔTdiVt, differed between patients and controls. Significant correlation (p < 0.05) was found between ΔTdiTLC, ΔTmax and FVC. The ROC curve analysis for comparison of individual testing showed better accuracy with Δtmax than with ΔtdiTLC for FVC (AUC 0.76 and 0.27) and SNIP (AUC 0.71 and 0.25). Diaphragm thickness assessed by ultrasound significantly correlates with global respiratory alterations in patients with ALS. ΔTmax represents a new US index of early diaphragmatic dysfunction, better related with the routinely performed lung function tests. © 2016 Asian Pacific Society of Respirology.

Mortality impact of extreme winter temperatures

NASA Astrophysics Data System (ADS)

Díaz, Julio; García, Ricardo; López, César; Linares, Cristina; Tobías, Aurelio; Prieto, Luis

2005-01-01

During the last few years great attention has been paid to the evaluation of the impact of extreme temperatures on human health. This paper examines the effect of extreme winter temperature on mortality in Madrid for people older than 65, using ARIMA and GAM models. Data correspond to 1,815 winter days over the period 1986 1997, during which time a total of 133,000 deaths occurred. The daily maximum temperature (Tmax) was shown to be the best thermal indicator of the impact of climate on mortality. When total mortality was considered, the maximum impact occured 7 8 days after a temperature extreme; for circulatory diseases the lag was between 7 and 14 days. When respiratory causes were considered, two mortality peaks were evident at 4 5 and 11 days. When the impact of winter extreme temperatures was compared with that associated with summer extremes, it was found to occur over a longer term, and appeared to be more indirect.

Fatigue-environment interactions in a SiC/Ti-15-3 composite

NASA Technical Reports Server (NTRS)

Gayda, J.; Gabb, T. P.; Lerch, B. A.

1993-01-01

Load-controlled isothermal and nonisothermal fatigue lives of a (0-deg)s SiC/Ti-15-3 were evaluated at temperatures between 150 and 550 C and a target strain range of about 0.45 percent. In nonisothermal fatigue tests, load was first cycled at minimum temperature and then temperature was cycled at zero load. For fatigue tests with peak temperatures at or above 300 C, fatigue life was dramatically reduced compared to that at 150 C. The shortest life was produced by the nonisothermal test with the greatest temperature range (Delta T = 400 C) and highest peak temperature (T(max) = 550 C). Vacuum testing showed that much of the life reduction under isothermal and nonisothermal conditions was related to environmental effects, although the nature of the fatigue-environment interaction was decidedly different for the isothermal and nonisothermal test cycles which were studied.

Weather Types, temperature and relief relationship in the Iberian Peninsula: A regional adiabatic processes under directional weather types

NASA Astrophysics Data System (ADS)

Peña Angulo, Dhais; Trigo, Ricardo; Cortesi, Nicola; Gonzalez-Hidalgo, Jose Carlos

2016-04-01

We have analyzed at monthly scale the spatial distribution of Pearson correlation between monthly mean of maximum (Tmax) and minimum (Tmin) temperatures with weather types (WTs) in the Iberian Peninsula (IP), represent them in a high spatial resolution grid (10km x 10km) from MOTEDAS dataset (Gonzalez-Hidalgo et al., 2015a). The WT classification was that developed by Jenkinson and Collison, adapted to the Iberian Peninsula by Trigo and DaCamara, using Sea Level Pressure data from NCAR/NCEP Reanalysis dataset (period 1951-2010). The spatial distribution of Pearson correlations shows a clear zonal gradient in Tmax under the zonal advection produced in westerly (W) and easterly (E) flows, with negative correlation in the coastland where the air mass come from but positive correlation to the inland areas. The same is true under North-West (NW), North-East (NE), South-West (SW) and South-East (SE) WTs. These spatial gradients are coherent with the spatial distribution of the main mountain chain and offer an example of regional adiabatic phenomena that affect the entire IP (Peña-Angulo et al., 2015b). These spatial gradients have not been observed in Tmin. We suggest that Tmin values are less sensitive to changes in Sea Level Pressure and more related to local factors. These directional WT present a monthly frequency over 10 days and could be a valuable tool for downscaling processes. González-Hidalgo J.C., Peña-Angulo D., Brunetti M., Cortesi, C. (2015a): MOTEDAS: a new monthly temperature database for mainland Spain and the trend in temperature (1951-2010). International Journal of Climatology 31, 715-731. DOI: 10.1002/joc.4298 Peña-Angulo, D., Trigo, R., Cortesi, C., González-Hidalgo, J.C. (2015b): The influence of weather types on the monthly average maximum and minimum temperatures in the Iberian Peninsula. Submitted to Hydrology and Earth System Sciences.

Fluid inclusion and vitrinite-reflectance geothermometry compared to heat-flow models of maximum paleotemperature next to dikes, western onshore Gippsland Basin, Australia

USGS Publications Warehouse

Barker, C.E.; Bone, Y.; Lewan, M.D.

1999-01-01

Nine basalt dikes, ranging from 6 cm to 40 m thick, intruding the Upper Jurassic-Lower Cretaceous Strzelecki Group, western onshore Gippsland Basin, were used to study maximum temperatures (Tmax) reached next to dikes. Tmax was estimated from fluid inclusion and vitrinitereflectance geothermometry and compared to temperatures calculated using heat-flow models of contact metamorphism. Thermal history reconstruction suggests that at the time of dike intrusion the host rock was at a temperature of 100-135??C. Fracture-bound fluid inclusions in the host rocks next to thin dikes ( 1.5, using a normalized distance ratio used for comparing measurements between dikes regardless of their thickness. In contrast, the pattern seen next to the thin dikes is a relatively narrow zone of elevated Rv-r. Heat-flow modeling, along with whole rock elemental and isotopic data, suggests that the extended zone of elevated Rv-r is caused by a convection cell with local recharge of the hydrothermal fluids. The narrow zone of elevated Rv-r found next to thin dikes is attributed to the rise of the less dense, heated fluids at the dike contact causing a flow of cooler groundwater towards the dike and thereby limiting its heating effects. The lack of extended heating effects suggests that next to thin dikes an incipient convection system may form in which the heated fluid starts to travel upward along the dike but cooling occurs before a complete convection cell can form. Close to the dike contact at X/D 1.5. ?? 1998 Elsevier Science B.V. All rights reserved.

Snoek Relaxation in Fe-Cr Alloys and Interstitial-Substitutional Interaction

NASA Astrophysics Data System (ADS)

Golovin, I. S.; Blanter, M. S.; Schaller, R.

1997-03-01

The internal friction (IF) spectra of -Fe, Fe-Cr ferritic alloys and Cr have been investigated in a frequency range of 0.01 to 10 Hz. A Snoek-type relaxation was found in all the investigated C doped Fe-Cr alloys, starting from pure Fe and finishing with pure Cr. The temperature location of the Snoek peak (Tmax) in -Fe was found to be 315 K (1 Hz). The activation energy deduced from the T - f shift was 0.81 eV. Tmax in Cr was 433 K with an activation energy of 1.11 eV. The Snoek-type peaks in Fe-Cr alloys are much wider than in pure Fe or pure Cr. The temperature location of the peak versus chromium content curve exhibits a maximum in the vicinity of 35 wt% Cr (Tmax was 573 to 578 K, f 1.2 Hz and the activation energy was about 1.45 eV). It is important that Cr atoms in α-Fe have a more pronounced influence on the temperature location of the peak than Fe atoms have in chromium. A new model based on the atomic interactions is proposed to explain the influence of composition on Snoek peak location. The internal friction has been simulated by a Monte Carlo method, using C-C and C-substitutional atom (s) interaction energies. A model of long-range strain-induced (elastic) interaction supplemented by the chemical interaction in the two nearest coordination shells around an immobile substitutional atom was used for the C-s interaction. The interatomic interaction was supposed to affect IF by changing both the carbon atom arrangement (short-range order) and the energy of C atoms in octahedral interstices, and therefore the activation energy of IF. The peak temperatue calculated coincides well with the experimental ones if the value for the chemical interaction in the first coordination shell (Hchem) for C-Cr in Fe is - 0.15 eV and for C-Fe in Cr +0.15 eV. The difference in the influence of Cr in α-Fe and Fe in Cr is accounted for by a difference in the elastic and chemical interaction both between the carbon atoms and the substitutional atoms. The relaxation process in chromium Fe-based alloys is due to the carbon atom diffusion under stress between octahedral interstices of first and second coordination shells around the Cr atoms, and in Cr-based alloys, between second and third shells around the Fe atoms.

Effect of oscillator strength and intermediate resonance on the performance of resonant phonon-based terahertz quantum cascade lasers

NASA Astrophysics Data System (ADS)

Fathololoumi, S.; Dupont, E.; Wasilewski, Z. R.; Chan, C. W. I.; Razavipour, S. G.; Laframboise, S. R.; Huang, Shengxi; Hu, Q.; Ban, D.; Liu, H. C.

2013-03-01

We experimentally investigated the effect of oscillator strength (radiative transition diagonality) on the performance of resonant phonon-based terahertz quantum cascade lasers that have been optimized using a simplified density matrix formalism. Our results show that the maximum lasing temperature (Tmax) is roughly independent of laser transition diagonality within the lasing frequency range of the devices under test (3.2-3.7 THz) when cavity loss is kept low. Furthermore, the threshold current can be lowered by employing more diagonal transition designs, which can effectively suppress parasitic leakage caused by intermediate resonance between the injection and the downstream extraction levels. Nevertheless, the current carrying capacity through the designed lasing channel in more diagonal designs may sacrifice even more, leading to electrical instability and, potentially, complete inhibition of the device's lasing operation. We propose a hypothesis based on electric-field domain formation and competition/switching of different current-carrying channels to explain observed electrical instability in devices with lower oscillator strengths. The study indicates that not only should designers maximize Tmax during device optimization but also they should always consider the risk of electrical instability in device operation.

Liquid and vapour water transfer through whey protein/lipid emulsion films.

PubMed

Kokoszka, Sabina; Debeaufort, Frederic; Lenart, Andrzej; Voilley, Andree

2010-08-15

Edible films and coatings based on protein/lipid combinations are among the new products being developed in order to reduce the use of plastic packaging polymers for food applications. This study was conducted to determine the effect of rapeseed oil on selected physicochemical properties of cast whey protein films. Films were cast from heated (80 degrees C for 30 min) aqueous solutions of whey protein isolate (WPI, 100 g kg(-1) of water) containing glycerol (50 g kg(-1) of WPI) as a plasticiser and different levels of added rapeseed oil (0, 1, 2, 3 and 4% w/w of WPI). Measurements of film microstructure, laser light-scattering granulometry, differential scanning calorimetry, wetting properties and water vapour permeability (WVP) were made. The emulsion structure in the film suspension changed significantly during drying, with oil creaming and coalescence occurring. Increasing oil concentration led to a 2.5-fold increase in surface hydrophobicity and decreases in WVP and denaturation temperature (T(max)). Film structure and surface properties explain the moisture absorption and film swelling as a function of moisture level and time and consequently the WVP behaviour. Small amounts of rapeseed oil favourably affect the WVP of WPI films, particularly at higher humidities. Copyright (c) 2010 Society of Chemical Industry.

[SEASONAL VARIATION OF MICROVOLT T-WAVE ALTERNANS IN PATIENTS WITH CARDIOVASCULAR DISEASE AND HEALTHY SUBJECTS].

PubMed

Halabi, Gh; Bulanova, N; Aleksandrova, S; Ivanov, G; Aleksandrova, M

2018-05-01

Objective - to access seasonal variation of microvolt T-wave alternans of ECG dispersion mapping in patients with cardiovascular disease and healthy subjects. ECG data of the three groups of healthy subjects have been compared: inhabitants of Beirut, Lebanon (n=51), inhabitants of Moscow, Russia (n=94) and ECG data of healthy subjects (n=44) from the testing ECG database of the PTB - The National Metrology Institute of Germany as well as a group of patients with cardiovascular disease (n=138), inhabitants of Beirut, Lebanon. Microvolt T-wave alternans of ECG dispersion mapping was evaluated in three points - Tbeginning, Tmaximum, Tend. In healthy subjects, the seasonal variation of ECG dispersion mapping microvolt T-wave alternans was nonexistent. Myocardial lesion is characterized by an increase in Tbeg, Tmax, Tend in relation to the healthy individuals. Tbeg values are minimal in winter and summer and increase in spring and autumn. Tend values were reversed - they were maximal in winter and summer, decreasing in spring-autumn period. Seasonal variation of Tmax - Tbeg, and Tmax -Tend was detected: Tmax - Tbeg increased in the winter-summer period and decreased in spring and autumn, Tmax-Tend - increased in the spring-autumn period in relation to the winter-summer period. In patients with cardiovascular disease, in contrast to the healthy, there is a seasonal variation in microvolt T-wave alternans of ECG dispersion mapping, with the maximum differences in the winter and spring seasons, which should be taken into account when applying the method in clinical practice.

Pharmacokinetics of cyclosporin in children with stable renal transplants.

PubMed

Tam, J C; Earl, J W; Willis, N S; Farquhar, J E; Nath, C E; Knight, J F; Hodson, E M

2000-12-01

Fourteen children, aged between 5 and 17 years, with stable renal graft function and stable cyclosporin A (CSA) trough levels (Cmin) were studied. They had been taking CSA 12-hourly since their transplant 1.5-9 years previously, with the average dose of Neoral being 6.4 (range 4.4-8.4) mg/kg per day. CSA whole blood levels were measured at 0, 20, and 40 min, and at 1, 1.5, 2, 2.5, 3, 4, 6, and 8 h following the morning dose using the Abbott TDx fluorescence polarization immunoassay. The area under the concentration time curve (AUC), clearance adjusted for bioavailability (CL/F), and steady-state volume of distribution adjusted for bioavailability (Vss/F) were determined using model-independent pharmacokinetic analysis. Delay time (Tdel), peak concentration (Cmax), time to peak concentration (Tmax), and Cmin were also determined and correlated with AUC and other parameters. The Tdel in absorption varied from 0.3 to 1.6 (mean 0.73) h, resulting in a similarly variable time to Tmax of 1-2.4 h (mean 1.59). Tmax was related to the age of the patient (Tmax = 0.027 age + 1.41, r2 = 0.56, P < 0.005). The AUC showed good correlation with Cmax (Cmax = 0.25 AUC + 423.32, r2 = 0.96, P < 0.0005). Cmax appears to be a more-suitable measure of exposure to CSA than Cmin. Prediction of Tmax from the age of the child may help to overcome the problem of when to collect blood for peak levels.

A Novel Web Application to Analyze and Visualize Extreme Heat Events

NASA Astrophysics Data System (ADS)

Li, G.; Jones, H.; Trtanj, J.

2016-12-01

Extreme heat is the leading cause of weather-related deaths in the United States annually and is expected to increase with our warming climate. However, most of these deaths are preventable with proper tools and services to inform the public about heat waves. In this project, we have investigated the key indicators of a heat wave, the vulnerable populations, and the data visualization strategies of how those populations most effectively absorb heat wave data. A map-based web app has been created that allows users to search and visualize historical heat waves in the United States incorporating these strategies. This app utilizes daily maximum temperature data from NOAA Global Historical Climatology Network which contains about 2.7 million data points from over 7,000 stations per year. The point data are spatially aggregated into county-level data using county geometry from US Census Bureau and stored in Postgres database with PostGIS spatial capability. GeoServer, a powerful map server, is used to serve the image and data layers (WMS and WFS). The JavaScript-based web-mapping platform Leaflet is used to display the temperature layers. A number of functions have been implemented for the search and display. Users can search for extreme heat events by county or by date. The "by date" option allows a user to select a date and a Tmax threshold which then highlights all of the areas on the map that meet those date and temperature parameters. The "by county" option allows the user to select a county on the map which then retrieves a list of heat wave dates and daily Tmax measurements. This visualization is clean, user-friendly, and novel because while this sort of time, space, and temperature measurements can be found by querying meteorological datasets, there does not exist a tool that neatly packages this information together in an easily accessible and non-technical manner, especially in a time where climate change urges a better understanding of heat waves.

Epi-Side-Down Mounting of Interband Cascade Lasers for Army Applications

DTIC Science & Technology

2006-11-01

retain the principal advantage of electron recycling . However, unlike the QCL, the ICL relies on the cascading of interband optical transitions as...9.0 Cu 393 17 SiC 120 4 AlN 230 (high grade –Tsekoun 2006) 4.5, 4.3 Indium 83.7 24.8@ 20C 2 device ridge and an effective heat spreader ...65.3 K/W M271 epi-side down 8-μm x 1-mm mesa TmaxCW= 212K 4 were vital and survived multiple cryogenic to room temperature recyclings . Fig. 4

Enhanced late gas generation potential of petroleum source rocks via recombination reactions: Evidence from the Norwegian North Sea

NASA Astrophysics Data System (ADS)

Erdmann, Michael; Horsfield, Brian

2006-08-01

Gas generation in the deep reaches of sedimentary basins is usually considered to take place via the primary cracking of short alkyl groups from overmature kerogen or the secondary cracking of petroleum. Here, we show that recombination reactions ultimately play the dominant role in controlling the timing of late gas generation in source rocks which contain mixtures of terrigeneous and marine organic matter. These reactions, taking place at low levels of maturation, result in the formation of a thermally stable bitumen, which is the major source of methane at very high maturities. The inferences come from pyrolysis experiments performed on samples of the Draupne Formation (liptinitic Type II kerogen) and Heather Formation (mixed marine-terrigeneous Type III kerogen), both Upper Jurassic source rocks stemming from the Norwegian northern North Sea Viking Graben system. Non-isothermal closed system micro scale sealed vessel (MSSV) pyrolysis, non-isothermal open system pyrolysis and Rock Eval type pyrolysis were performed on the solvent extracted, concentrated kerogens of the two immature samples. The decrease of C 6+ products in the closed system MSSV pyrolysis provided the basis for the calculation of secondary gas (C 1-5) formation. Subtraction of the calculated secondary gas from the total observed gas yields a "remaining" gas. In the case of the Draupne Formation this is equivalent to primary gas cracked directly from the kerogen, as detected by a comparison with multistep open pyrolysis data. For the Heather Formation the calculated remaining gas formation profile is initially attributable to primary gas but there is a second major gas pulse at very high temperature (>550 °C at 5.0 K min -1) that is not primary. This has been explained by a recondensation process where first formed high molecular weight compounds in the closed system yield a macromolecular material that undergoes secondary cracking at elevated temperatures. The experiments provided the input for determination of kinetic parameters of the different gas generation types, which were used for extrapolations to a linear geological heating rate of 10 -11 K min -1. Peak generation temperatures for the primary gas generation were found to be higher for Heather Formation ( Tmax = 190 °C, equivalent to Ro appr. 1.7%) compared to Draupne Formation ( Tmax = 175 °C, equivalent to appr. Ro 1.3%). Secondary gas peak generation temperatures were calculated to be 220 °C for the Heather Formation and 205 to 215 °C for the Draupne Formation, respectively, with equivalent vitrinite reflectance values ( Ro) between 2.4% and 2.0%. The high temperature secondary gas formation from cracking of the recombination residue as detected for the Heather Formation is quantitatively important and is suggested to occur at very high temperatures ( Tmax approx. 250 °C) for geological heating rates. The prediction of a significant charge of dry gas from the Heather Formation at very high maturity levels has important implications for petroleum exploration in the region, especially to the north of the Viking Graben where Upper Jurassic sediments are sufficiently deep buried to have experienced such a process.

Evaluations of Some Scheduling Algorithms for Hard Real-Time Systems

DTIC Science & Technology

1990-06-01

construct because the mechanism is a dispatching procedure. Since all nonpreemptive schedules are contained in the set of all preemptive schedules, the...optimal value of Tmax in the preemptive case is at least a lower bound on the optimal Tmax for the nonpreemptive schedules. This principle is the basis...23 b. Nonpreemptable Version .............................................. 24 4. The Minimize Maximum Tardiness with Earliest Start

Reactivity of a Carbon-Supported Single-Site Molybdenum Dioxo Catalyst for Biodiesel Synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mouat, Aidan R.; Lohr, Tracy L.; Wegener, Evan C.

2016-08-23

A single-site molybdenum dioxo catalyst, (O c) 2Mo(=O) 2@C, was prepared via direct grafting of MoO 2Cl 2(dme) (dme = 1,2-dimethoxyethane) on high-surface- area activated carbon. The physicochemical and chemical properties of this catalyst were fully characterized by N 2 physisorption, ICP-AES/OES, PXRD, STEM, XPS, XAS, temperature-programmed reduction with H 2 (TPR-H 2), and temperature-programmed NH 3 desorption (TPD-NH 3). The single-site nature of the Mo species is corroborated by XPS and TPR-H 2 data, and it exhibits the lowest reported MoO x Tmax of reduction reported to date, suggesting a highly reactive MoVI center. (O c) 2Mo(=O) 2@C catalyzesmore » the transesterification of a variety of esters and triglycerides with ethanol, exhibiting high activity at moderate temperatures (60-90 °C) and with negligible deactivation. (O c) 2Mo(=O) 2@C is resistant to water and can be recycled at least three times with no loss of activity. The transesterification reaction is determined experimentally to be first order in [ethanol] and first order in [Mo] with ΔH = 10.5(8) kcal mol -1 and ΔS = -32(2) eu. The low energy of activation is consistent with the moderate conditions needed to achieve rapid turnover. This highly active carbon-supported single-site molybdenum dioxo species is thus an efficient, robust, and lowcost catalyst with significant potential for transesterification processes.« less

Modelling growth of Penicillium expansum and Aspergillus niger at constant and fluctuating temperature conditions.

PubMed

Gougouli, Maria; Koutsoumanis, Konstantinos P

2010-06-15

The growth of Penicillium expansum and Aspergillus niger, isolated from yogurt production environment, was investigated on malt extract agar with pH=4.2 and a(w)=0.997, simulating yogurt, at isothermal conditions ranging from -1.3 to 35 degrees C and from 5 to 42.3 degrees C, respectively. The growth rate (mu) and (apparent) lag time (lambda) of the mycelium growth were modelled as a function of temperature using a Cardinal Model with Inflection (CMI). The results showed that the CMI can describe successfully the effect of temperature on fungal growth within the entire biokinetic range for both isolates. The estimated values of the CMI for mu were T(min)=-5.74 degrees C, T(max)=30.97 degrees C, T(opt)=22.08 degrees C and mu(opt)=0.221 mm/h for P. expansum and T(min)=10.13 degrees C, T(max)=43.13 degrees C, T(opt)=31.44 degrees C, and mu(opt)=0.840 mm/h for A. niger. The cardinal values for lambda were very close to the respective values for mu indicating similar temperature dependence of the growth rate and the lag time of the mycelium growth. The developed models were further validated under fluctuating temperature conditions using various dynamic temperature scenarios. The time-temperature conditions studied included single temperature shifts before or after the end of the lag time and continuous periodic temperature fluctuations. The prediction of growth at changing temperature was based on the assumption that after a temperature shift the growth rate is adopted instantaneously to the new temperature, while the lag time was predicted using a cumulative lag approach. The results showed that when the temperature shifts occurred before the end of the lag, they did not cause any significant additional lag and the observed total lag was very close to the cumulative lag predicted by the model. In experiments with temperature shifts after the end of the lag time, accurate predictions were obtained when the temperature profile included temperatures which were inside the region of growth, showing that the assumption that mu is adopted instantaneously to the current temperature is concrete. In contrast, for scenarios with temperatures close or outside the growth region the models overestimated growth, indicating that fungi were stressed by this type of temperature shifts. The present study provides useful data for understanding the behavior of P. expansum and A. niger at dynamic temperature conditions while the developed models can be used as effective tools in assessing the risk of fungal spoilage and predicting shelf life of foods. Copyright 2010. Published by Elsevier B.V.

The Affinity of D2-Like Dopamine Receptor Antagonists Determines the Time to Maximal Effect on Cocaine Self-Administration

PubMed Central

Tabet, Michael R.; Norman, Mantana K.; Fey, Brittney K.; Tsibulsky, Vladimir L.; Millard, Ronald W.

2011-01-01

Differences in the time to maximal effect (Tmax) of a series of dopamine receptor antagonists on the self-administration of cocaine are not consistent with their lipophilicity (octanol-water partition coefficients at pH 7.4) and expected rapid entry into the brain after intravenous injection. It was hypothesized that the Tmax reflects the time required for maximal occupancy of receptors, which would occur as equilibrium was approached. If so, the Tmax should be related to the affinity for the relevant receptor population. This hypothesis was tested using a series of nine antagonists having a 2500-fold range of Ki or Kd values for D2-like dopamine receptors. Rats self-administered cocaine at regular intervals and then were injected intravenously with a dose of antagonist, and the self-administration of cocaine was continued for 6 to 10 h. The level of cocaine at the time of every self-administration (satiety threshold) was calculated throughout the session. The satiety threshold was stable before the injection of antagonist and then increased approximately 3-fold over the baseline value at doses of antagonists selected to produce this approximately equivalent maximal magnitude of effect (maximum increase in the equiactive cocaine concentration, satiety threshold; Cmax). Despite the similar Cmax, the mean Tmax varied between 5 and 157 min across this series of antagonists. Furthermore, there was a strong and significant correlation between the in vivo Tmax values for each antagonist and the affinity for D2-like dopamine receptors measured in vitro. It is concluded that the cocaine self-administration paradigm offers a reliable and predictive bioassay for measuring the affinity of a competitive antagonist for D2-like dopamine receptors. PMID:21606176

Symmetricity analysis of time to peak parameter of indocyanine green dynamics

NASA Astrophysics Data System (ADS)

An, Yuri; Lee, Jungsul; Choi, Chulhee

2013-03-01

We have previously discovered that near-infrared optical imaging of indocyanine green (ICG) signal and analyzing its dynamics can be applied for measurement of blood perfusion rate and detection of Raynaud's phenomenon (RP). Especially, RP is closely associated with abnormal vasomotor responses and can progress to tissue necrosis due to excessively sustained vasoconstriction. Therefore, early detecting of RP is one of important implication to prevent tissue damage from peripheral vascular disorders. In the present study, we propose new analysis and scoring method of symmetricity of Tmax value of left and right extremities. Moreover, this symmetricity analysis can give further information about microvascular insufficiency. For validation of the proposed method, we tested whether the segmental and paired analysis of Tmax value (time-to-peak) of ICG dynamics can be used for sensitive diagnosis of microvascular abnormalities which cannot be detected by conventional methods. From the near-infrared images of diabetes mellitus patients with vascular complications, the trend of asymmetry in Tmax value was observed. We assumed that decreasing local blood perfusion by autonomic nerve dysfunction causes the asymmetric Tmax value of right and left feet. These results collectively indicate that the proposed method can be used as a useful diagnostic tool for RP or other microvascular disorders.

Music as an auditory stimulus in stroke patients.

PubMed

Antić, Sonja; Galinović, Ivana; Lovrendić-Huzjan, Arijana; Vuković, Vlasta; Jurasić, Miljenka-Jelena; Demarin, Vida

2008-01-01

Auditory stimulation increases mean blood flow velocity (MBFV) in the middle cerebral artery (MCA) in healthy individuals. Our aim was to monitor such changes in the affected MCA of patients with acute ischemic stroke (AIS). The study included 66 non-thrombolysed patients with AIS who were divided into groups according to National Institutes of Health Stroke Scale (NIHSS) score. Group I consisted of patients with NIHSS score 10 and group II with NIHSS score > or =11. Affected MCA was insonated with transcranial Doppler (TCD). MCA MBFVs were monitored during listening to music for 30 minutes. The first response of MBFV increase was measured as time (Tmax) and percentage of amplitude change (Amax). Pearson Chi-Square test was used. In 78.85% of patients there was a significant increase in MBFV compared to baseline values as a reaction to the music. There was no significant difference in Tmax or Amax between the two groups. However, a trend of longer Tmax was observed with every 2 NIHSS score increase. Music is an auditory stimulus in stroke patients and can be measured with TCD as MCA MBFV increase. Although our study showed no significant change of reaction time with the severity of stroke, a trend of prolonged Tmax was observed with NIHSS score increase.

High-pressure granulites in the Fuping Complex of the central North China Craton: Metamorphic P-T-t evolution and tectonic implications

NASA Astrophysics Data System (ADS)

Qian, Jiahui; Yin, Changqing; Zhang, Jian; Ma, Li; Wang, Luojuan

2018-04-01

Mafic granulites in the Fuping Complex occur as lenses or boudins within high-grade TTG (Trondhjemite-Tonalite-Granodiorite) gneisses. Petrographic observations reveal four generations of mineral assemblage in the granulites: an inclusion assemblage of hornblende + plagioclase + ilmenite + quartz within garnet core; an inferred peak assemblage composed of garnet ± hornblende + plagioclase + clinopyroxene + rutile/ilmenite + quartz; a decompression assemblage characterized by symplectites of clinopyroxene ± orthopyroxene + plagioclase, coronae of plagioclase ± clinopyroxene ± hornblende around embayed garnet porphyroblasts or a two-pyroxene association; and a late amphibolite-facies retrogressive assemblage. Two representative samples were used for pseudosection modeling in NCFMASHTO model system to determine their metamorphic evolution. The results show that these granulites experienced a high-pressure stage of metamorphism with peak P-T conditions of 12-13 kbar and 760-800 °C (Pmax) and a post-peak history under P-T conditions of ∼9.0 kbar and 805-835 °C (Tmax), indicating a nearly isothermal decompression process (ITD) with a slight heating. Metamorphic evolution from the Pmax to the Tmax is predicted to be dominated by garnet breakdown through continuous metamorphic reactions of garnet + quartz ± diopside = hornblende + plagioclase + liquid and garnet + quartz + hornblende = plagioclase + diopside + liquid + orthopyroxene. Further metamorphic evolution after the Tmax is dominated by cooling, suggesting that high-pressure (HP) granulites may also exist in the Fuping Complex. Metamorphic zircons in the Fuping HP mafic granulites have left inclined REE patterns, Ti contents of 1.68-6.88 ppm and crystallization temperatures of 602-712 °C. SIMS zircon U-Pb dating on these zircons yields 207Pb/206Pb ages of 1891 ± 14 Ma and 1849 ± 6 Ma, interpreted to represent the cooling stage of metamorphism. The P-T-t evolution of the Fuping HP mafic granulites records well the protracted Paleoproterozoic orogenic event occurred in the central North China Craton.

Numerical Modeling of Hydrothermal Circulation at the Longqi-1 Field: Southwest Indian Ridge

NASA Astrophysics Data System (ADS)

Guo, Z.; Lowell, R. P.; Tao, C.; Rupke, L.; Lewis, K. C.

2017-12-01

The Longqi-1(Dragon Flag) hydrothermal field is the first high-temperature hydrothermal system observed on the ultra-slow spreading Southwest Indian Ridge. Hydrothermal vents with temperatures near 380 °C are localized by detachment faulting within which extensional deformation likely increases permeability to provide preferred pathways for hydrothermal discharge. To better understand the Longqi-1 circulation system, we construct a 2-D numerical simulations in a NaCl- H2O fluid constrained by key observational data, such as vent temperature and heat output, crust structure derived from seismic data, and fault zone geometry deduced from seismicity. Heat output from AUV surveys is estimated to be » 300 ± 100 MW, and this value, in conjunction with vent temperature was used with the single-pass modeling approach to obtain an average permeability of 10-13 m-2 within the fault zone. In analogy with other fault-controlled hydrothermal systems such as Logatchev-1 we assume a lower background permeability of 10-14 m-2. The top boundary of the system is permeable and maintained at constant seafloor pressure, which is divided into two parts by the detachment fault. The pressure of the southern part is lower than the northern part to simulate the effect of the seafloor topography. The top boundary is upstream weighted to allow high temperature fluid to exit, while recharging fluid is maintained at 10°C. The bottom boundary is impermeable and is given a fixed temperature distribution at a depth of 7 km below the seafloor. The highest value Tmax is maintained over a distance given lateral distance and decreases linearly towards two ends to 300 °C. The salinity is set to 3.2 wt. % NaCl, and the simulations are assumed to be single phase. The results show that with a 7 km deep circulation system, Tmax = 550 oC gives a reasonable temperature and heat output of venting plume.We infer that the observed high salinity results from serpentinization reactions. Assuming all salinity in excess of seawater comes from uptake of H2O during serpentinization, we can estimate the rate of reaction and heat release of serpentinezation based on a simplified reaction equation, observed heat output and salinity data. The estimated rate of heat release during serpentinization is 20 MW. This is approximately 10% of the heat output of Dragon Flag vent field.

Design of a 1200-V ultra-thin partial SOI LDMOS with n-type buried layer

NASA Astrophysics Data System (ADS)

Qiao, Ming; Wang, Yuru; Li, Yanfei; Zhang, Bo; Li, Zhaoji

2014-11-01

A novel 1200-V ultra-thin partial silicon-on-insulator (PSOI) lateral double-diffusion metal oxide semiconductor (LDMOS) with n-type buried (n-buried) layer (NBL PSOI LDMOS) is proposed in this paper. The new PSOI LDMOS features an n-buried layer underneath the n-type drift (n-drift) region close to the source side, providing a large conduction region for majority carriers and a silicon window to improve self-heating effect (SHE). A combination of uniform and linear variable doping (ULVD) profile is utilized in the n-drift region, which alleviates the inherent tradeoff between specific on-resistance (Ron,sp) and breakdown voltage (BV). With the n-drift region length of 80 μm, the NBL PSOI LDMOS obtains a high BV of 1243 V which is improved by around 105 V in comparison to the conventional SOI LDMOS with linear variable doping (LVD) profile for the n-drift region (LVD SOI LDMOS). Besides, the 1200-V NBL PSOI LDMOS has a lower maximum temperature (Tmax) of 333 K at a power (P) of 1 mW/μm which is reduced by around 61 K. Meanwhile, Ron,sp and Tmax of the NBL PSOI LDMOS are lower than those of the conventional LVD SOI LDMOS for a wide range of BV.

A simple and inexpensive system for controlling body temperature in small animal experiments using MRI and the effect of body temperature on the hepatic kinetics of Gd-EOB-DTPA.

PubMed

Murase, Kenya; Assanai, Purapan; Takata, Hiroshige; Saito, Shigeyoshi; Nishiura, Motoko

2013-12-01

The purpose of this study was to develop a simple and inexpensive system for controlling body temperature in small animal experiments using magnetic resonance imaging (MRI) and to investigate the effect of body temperature on the kinetic behavior of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) in the liver. In our temperature-control system, body temperature was controlled using a feedback-regulated heated or cooled air flow generated by two Futon dryers. The switches of the two Futon dryers were controlled using a digital temperature controller, in which the rectal temperature of a mouse measured by an optical fiber thermometer was used as the input. In experimental studies, male ICR mice aged 8weeks old were used and allocated into 5 groups (39-, 36-, 33-, 30-, and 27-degree groups, n=10), in which the body temperature was maintained at 39 °C, 36 °C, 33 °C, 30 °C, and 27 °C, respectively, using our system. The dynamic contrast-enhanced MRI (DCE-MRI) data were acquired with an MRI system for animal experiments equipped with a 1.5-Tesla permanent magnet, for approximately 43min, after the injection of Gd-EOB-DTPA into the tail vein. After correction of the image shift due to the temperature-dependent drift of the Larmor frequency using the gradient-based image registration method with robust estimation of displacement parameters, the kinetic behavior of Gd-EOB-DTPA was analyzed using an empirical mathematical model. With the use of this approach, the upper limit of the relative enhancement (A), the rates of contrast uptake (α) and washout (β), the parameter related to the slope of early uptake (q), the area under the curve (AUC), the maximum relative enhancement (REmax), the time to REmax (Tmax), and the elimination half-life of the contrast agent (T1/2) were calculated. The body temperature of mice could be controlled well by use of our system. Although there were no significant differences in α, AUC, and q among groups, there were significant differences in A, REmax, β, Tmax, and T1/2, indicating that body temperature significantly affects the kinetic behavior of Gd-EOB-DTPA in the liver. In conclusion, our system will be useful for controlling body temperature in small animal experiments using MRI. Because body temperature significantly affects the kinetic behavior of Gd-EOB-DTPA in the liver, the control of body temperature is essential and should be carefully considered when performing DCE-MRI studies in small animal experiments. © 2013.

High resolution statistical downscaling of the EUROSIP seasonal prediction. Application for southeastern Romania

NASA Astrophysics Data System (ADS)

Busuioc, Aristita; Dumitrescu, Alexandru; Dumitrache, Rodica; Iriza, Amalia

2017-04-01

Seasonal climate forecasts in Europe are currently issued at the European Centre for Medium-Range Weather Forecasts (ECMWF) in the form of multi-model ensemble predictions available within the "EUROSIP" system. Different statistical techniques to calibrate, downscale and combine the EUROSIP direct model output are used to optimize the quality of the final probabilistic forecasts. In this study, a statistical downscaling model (SDM) based on canonical correlation analysis (CCA) is used to downscale the EUROSIP seasonal forecast at a spatial resolution of 1km x 1km over the Movila farm placed in southeastern Romania. This application is achieved in the framework of the H2020 MOSES project (http://www.moses-project.eu). The combination between monthly standardized values of three climate variables (maximum/minimum temperatures-Tmax/Tmin, total precipitation-Prec) is used as predictand while combinations of various large-scale predictors are tested in terms of their availability as outputs in the seasonal EUROSIP probabilistic forecasting (sea level pressure, temperature at 850 hPa and geopotential height at 500 hPa). The predictors are taken from the ECMWF system considering 15 members of the ensemble, for which the hindcasts since 1991 until present are available. The model was calibrated over the period 1991-2014 and predictions for summers 2015 and 2016 were achieved. The calibration was made for the ensemble average as well as for each ensemble member. The model was developed for each lead time: one month anticipation for June, two months anticipation for July and three months anticipation for August. The main conclusions from these preliminary results are: best predictions (in terms of the anomaly sign) for Tmax (July-2 months anticipation, August-3 months anticipation) for both years (2015, 2016); for Tmin - good predictions only for August (3 months anticipation ) for both years; for precipitation, good predictions for July (2 months anticipation) in 2015 and August (3 months anticipation) in 2016; failed prediction for June (1-month anticipation) for all parameters. To see if the results obtained for 2015 and 2016 summers are in agreement with the general ECMWF model performance in forecast of the three predictors used in the CCA SDM calibration, the mean bias and root mean square errors (RMSE) calculated over the entire period in each grid point, for each ensemble member and ensemble average were computed. The obtained results are confirmed, showing highest ECMWF performance in forecasting of the three predictors for 3 months anticipation (August) and lowest performance for one month anticipation (June). The added value of the CCA SDM in forecasting local Tmax/Tmin and total precipitation was compared to the ECMWF performance using nearest grid point method. Comparisons were performed for the 1991-2014 period, taking into account the forecast made in May for July. An important improvement was found for the CCA SDM predictions in terms of the RMSE value (computed against observations) for Tmax/Tmin and less for precipitation. The tests are in progress for the other summer months (June, July).

Urban climate effects on extreme temperatures in Madison, Wisconsin, USA

NASA Astrophysics Data System (ADS)

Schatz, Jason; Kucharik, Christopher J.

2015-09-01

As climate change increases the frequency and intensity of extreme heat, cities and their urban heat island (UHI) effects are growing, as are the urban populations encountering them. These mutually reinforcing trends present a growing risk for urban populations. However, we have limited understanding of urban climates during extreme temperature episodes, when additional heat from the UHI may be most consequential. We observed a historically hot summer and historically cold winter using an array of up to 150 temperature and relative humidity sensors in and around Madison, Wisconsin, an urban area of population 402 000 surrounded by lakes and a rural landscape of agriculture, forests, wetlands, and grasslands. In the summer of 2012 (third hottest since 1869), Madison’s urban areas experienced up to twice as many hours ⩾32.2 °C (90 °F), mean July TMAX up to 1.8 °C higher, and mean July TMIN up to 5.3 °C higher than rural areas. During a record setting heat wave, dense urban areas spent over four consecutive nights above the National Weather Service nighttime heat stress threshold of 26.7 °C (80 °F), while rural areas fell below 26.7 °C nearly every night. In the winter of 2013-14 (coldest in 35 years), Madison’s most densely built urban areas experienced up to 40% fewer hours ⩽-17.8 °C (0 °F), mean January TMAX up to 1 °C higher, and mean January TMIN up to 3 °C higher than rural areas. Spatially, the UHI tended to be most intense in areas with higher population densities. Temporally, both daytime and nighttime UHIs tended to be slightly more intense during more-extreme heat days compared to average summer days. These results help us understand the climates for which cities must prepare in a warming, urbanizing world.

Emergence of the significant local warming of Korea in CMIP5 projections

NASA Astrophysics Data System (ADS)

Boo, Kyung-On; Shim, Sungbo; Kim, Jee-Eun

2016-04-01

According to IPCC AR5, anthropogenic influence on warming is obvious in local scales, especially in some tropical regions. Detection of significant local warming is important for adaptation to climate change of society and ecosystem. Recently much attention has focused on the time of emergence (ToE) for the signal of anthropogenic climate change against the natural climate variability. Motivated from the previous studies, this study analyzes ToE of regional surface air temperature over Korea. Simulations of CMIP5 15 models are used for RCP 2.6, 4.5 and 8.5. For each year, JJA and DJF temperature anomalies are calculated for the time period 1900-1929. For noise of interannual variability, natural-only historical simulations of CMIP5 12 models are used and the standard deviation of the time series is obtained. For signal of warming, we examine the year when the signal above 2 standard deviations is detected in 80% of the models using 30-year smoothed time series. According to our results, interannual variability is larger in land than ocean. Seasonally, it is larger in winter than in summer. Accordingly, ToE of summertime temperature is earlier than that in winter and is expected to appear in 2030s from three RCPs. The seasonal difference is consistent with previous studies. Wintertime ToE appears in 2040s for RCP85 and 2060s for RCP4.5. The different emergence time between RCP8.5 and RCP4.5 reflects the influence of mitigation. In a similar way, daily maximum and minimum temperatures are analyzed. ToE of Tmin appears earlier than that of Tmax and difference is small. Acknowledgements. This study is supported by the National Institute of Meteorological Sciences, Korea Meteorological Administration (NIMR-2012-B-2).

Enhancement of the dark matter abundance before reheating: Applications to gravitino dark matter

NASA Astrophysics Data System (ADS)

Garcia, Marcos A. G.; Mambrini, Yann; Olive, Keith A.; Peloso, Marco

2017-11-01

In the first stages of inflationary reheating, the temperature of the radiation produced by inflaton decays is typically higher than the commonly defined reheating temperature TR H˜(ΓϕMP)1/2 where Γϕ is the inflaton decay rate. We consider the effect of particle production at temperatures at or near the maximum temperature attained during reheating. We show that the impact of this early production on the final particle abundance depends strongly on the temperature dependence of the production cross section. For ⟨σ v ⟩˜Tn/Mn +2, and for n <6 , any particle produced at Tmax is diluted by the later generation of entropy near TR H. This applies to cases such as gravitino production in low scale supersymmetric models (n =0 ) or NETDM models of dark matter (n =2 ). However, for n ≥6 the net abundance of particles produced during reheating is enhanced by over an order of magnitude, dominating over the dilution effect. This applies, for instance to gravitino production in high scale supersymmetry models where n =6 .

Simultaneous measurement of glucose blood–brain transport constants and metabolic rate in rat brain using in-vivo 1H MRS

PubMed Central

Du, Fei; Zhang, Yi; Zhu, Xiao-Hong; Chen, Wei

2012-01-01

Cerebral glucose consumption and glucose transport across the blood–brain barrier are crucial to brain function since glucose is the major energy fuel for supporting intense electrophysiological activity associated with neuronal firing and signaling. Therefore, the development of noninvasive methods to measure the cerebral metabolic rate of glucose (CMRglc) and glucose transport constants (KT: half-saturation constant; Tmax: maximum transport rate) are of importance for understanding glucose transport mechanism and neuroenergetics under various physiological and pathological conditions. In this study, a novel approach able to simultaneously measure CMRglc, KT, and Tmax via monitoring the dynamic glucose concentration changes in the brain tissue using in-vivo 1H magnetic resonance spectroscopy (MRS) and in plasma after a brief glucose infusion was proposed and tested using an animal model. The values of CMRglc, Tmax, and KT were determined to be 0.44±0.17 μmol/g per minute, 1.35±0.47 μmol/g per minute, and 13.4±6.8 mmol/L in the rat brain anesthetized with 2% isoflurane. The Monte-Carlo simulations suggest that the measurements of CMRglc and Tmax are more reliable than that of KT. The overall results indicate that the new approach is robust and reliable for in-vivo measurements of both brain glucose metabolic rate and transport constants, and has potential for human application. PMID:22714049

Effect of immobilization and retraining on torque-velocity relationship of human knee flexor and extensor muscles.

PubMed

Labarque, V L; Eijnde, B Op 't; Van Leemputte, M

2002-01-01

The effect of 2 weeks immobilization of the uninjured right knee and 10 weeks of retraining on muscle torque-velocity characteristics was investigated in nine young subjects. Left and right knee extension and flexion maximal voluntary isometric torque (Tmax) and dynamic torque at 60 degrees s(-1) (T60) and 180 degrees x s(-1) (T180) were measured before (PRE) and after immobilization (POST) and after 3 (R3) and 10 (R10) weeks of dynamic retraining. The torque-velocity relationship was quantified by expressing T60 and T180 relative to Tmax (NT60 and NT180, respectively). For the right extensor muscles, percutaneous biopsy samples were obtained from the vastus lateralis muscle and fibre type distribution was measured. POST extension and flexion torque (mean of Tmax, T60 and T180) decreased by 27% and 11%, respectively. During the course of the experiment, the changes in NT60 and NT180 were similar. POST extensor muscle NTV (mean of NT60 and NT180) was decreased significantly (12%, P<0.05), but no significant change was found for flexor muscle NTV (+ 3%). At R3 Tmax, dynamic torque and NTV were restored to normal. Unlike isometric torque, NTV did not change from R3 to R10. No changes in fibre type distribution were found. The adaptation of muscle length is suggested as the mechanism to explain the change in NTV.

The effects of tibial intraosseous versus intravenous amiodarone administration in a hypovolemic cardiac arrest procine model.

PubMed

Hampton, Kathryn; Wang, Eric; Argame, Jerome Ivan; Bateman, Tom; Craig, William; Johnson, Don

2016-01-01

This study compared the effects of amiodarone via tibial intraosseous (TIO) and intravenous (IV) routes on return of spontaneous circulation (ROSC), time to ROSC, maximum drug concentration (Cmax), time to maximum concentration (Tmax), and mean concentrations over time in a hypovolemic cardiac arrest model. Prospective, between subjects, randomized experimental design. TriService Research Facility. Yorkshire-cross swine (n = 28). Swine were anesthetized and placed into cardiac arrest. After 2 minutes, cardiopulmonary resuscitation (CPR) was initiated. After an additional 2 minute, 300 mg of amiodarone were administered via the TIO or the IV route. Blood samples were collected over 5 minutes. The plasma concentrations were analyzed using high-performance liquid chromatography tandem mass spectrometry. ROSC, time to ROSC, Cmax, Tmax, and mean concentrations over time. A multivariate analysis of variance indicated that there were no significant differences in the TIO and IV groups in ROSC (p = 0.515), time to ROSC (p = 0.300), Cmax (p = 0.291), or Tmax (p = 0.475). The mean Cmax of the TIO group was 56,292 ± 11,504 ng/mL compared to 74,258 ± 11,504 ng/mL for the IV group. The Tmax for TIO and IV groups were 120 ± 25 and 94 ± 25, respectively. A repeated measures analysis of variance indicated that there were no significant differences between the groups relative to concentrations over time (p > 0.05). The TIO provides rapid and reliable access to administer lifesaving medications during cardiac arrest.

Simultaneous measurement of glucose blood-brain transport constants and metabolic rate in rat brain using in-vivo 1H MRS.

PubMed

Du, Fei; Zhang, Yi; Zhu, Xiao-Hong; Chen, Wei

2012-09-01

Cerebral glucose consumption and glucose transport across the blood-brain barrier are crucial to brain function since glucose is the major energy fuel for supporting intense electrophysiological activity associated with neuronal firing and signaling. Therefore, the development of noninvasive methods to measure the cerebral metabolic rate of glucose (CMR(glc)) and glucose transport constants (K(T): half-saturation constant; T(max): maximum transport rate) are of importance for understanding glucose transport mechanism and neuroenergetics under various physiological and pathological conditions. In this study, a novel approach able to simultaneously measure CMR(glc), K(T), and T(max) via monitoring the dynamic glucose concentration changes in the brain tissue using in-vivo (1)H magnetic resonance spectroscopy (MRS) and in plasma after a brief glucose infusion was proposed and tested using an animal model. The values of CMR(glc), T(max), and K(T) were determined to be 0.44 ± 0.17 μmol/g per minute, 1.35 ± 0.47 μmol/g per minute, and 13.4 ± 6.8 mmol/L in the rat brain anesthetized with 2% isoflurane. The Monte-Carlo simulations suggest that the measurements of CMR(glc) and T(max) are more reliable than that of K(T). The overall results indicate that the new approach is robust and reliable for in-vivo measurements of both brain glucose metabolic rate and transport constants, and has potential for human application.

Methodology to predict a maximum follow-up period for breast cancer patients without significantly reducing the chance of detecting a local recurrence

NASA Astrophysics Data System (ADS)

Mould, Richard F.; Asselain, Bernard; DeRycke, Yann

2004-03-01

For breast cancer where the prognosis of early stage disease is very good and even when local recurrences do occur they can present several years after treatment, the hospital resources required for annual follow-up examinations of what can be several hundreds of patients are financially significant. If, therefore, there is some method to estimate a maximum length of follow-up Tmax necessary, then cost savings of physicians' time as well as outpatient workload reductions can be achieved. In modern oncology where expenses continue to increase exponentially due to staff salaries and the expense of chemotherapy drugs and of new treatment and imaging technology, the economic situation can no longer be ignored. The methodology of parametric modelling, based on the lognormal distribution is described, showing that useful estimates for Tmax can be made, by making a trade-off between Tmax and the fraction of patients who will experience a delay in detection of their local recurrence. This trade-off depends on the chosen tail of the lognormal. The methodology is described for stage T1 and T2 breast cancer and it is found that Tmax = 4 years which is a significant reduction on the usual maximum of 10 years of follow-up which is employed by many hospitals for breast cancer patients. The methodology is equally applicable for cancers at other sites where the prognosis is good and some local recurrences may not occur until several years post-treatment.

Imaging technique for real-time temperature monitoring during cryotherapy of lesions.

PubMed

Petrova, Elena; Liopo, Anton; Nadvoretskiy, Vyacheslav; Ermilov, Sergey

2016-11-01

Noninvasive real-time temperature imaging during thermal therapies is able to significantly improve clinical outcomes. An optoacoustic (OA) temperature monitoring method is proposed for noninvasive real-time thermometry of vascularized tissue during cryotherapy. The universal temperature-dependent optoacoustic response (ThOR) of red blood cells (RBCs) is employed to convert reconstructed OA images to temperature maps. To obtain the temperature calibration curve for intensity-normalized OA images, we measured ThOR of 10 porcine blood samples in the range of temperatures from 40°C to ?16°C and analyzed the data for single measurement variations. The nonlinearity (?Tmax) and the temperature of zero OA response (T0) of the calibration curve were found equal to 11.4±0.1°C and ?13.8±0.1°C, respectively. The morphology of RBCs was examined before and after the data collection confirming cellular integrity and intracellular compartmentalization of hemoglobin. For temperatures below 0°C, which are of particular interest for cryotherapy, the accuracy of a single temperature measurement was ±1°C, which is consistent with the clinical requirements. Validation of the proposed OA temperature imaging technique was performed for slow and fast cooling of blood samples embedded in tissue-mimicking phantoms.

Imaging technique for real-time temperature monitoring during cryotherapy of lesions

PubMed Central

Petrova, Elena; Liopo, Anton; Nadvoretskiy, Vyacheslav; Ermilov, Sergey

2016-01-01

Abstract. Noninvasive real-time temperature imaging during thermal therapies is able to significantly improve clinical outcomes. An optoacoustic (OA) temperature monitoring method is proposed for noninvasive real-time thermometry of vascularized tissue during cryotherapy. The universal temperature-dependent optoacoustic response (ThOR) of red blood cells (RBCs) is employed to convert reconstructed OA images to temperature maps. To obtain the temperature calibration curve for intensity-normalized OA images, we measured ThOR of 10 porcine blood samples in the range of temperatures from 40°C to −16°C and analyzed the data for single measurement variations. The nonlinearity (ΔTmax) and the temperature of zero OA response (T0) of the calibration curve were found equal to 11.4±0.1°C and −13.8±0.1°C, respectively. The morphology of RBCs was examined before and after the data collection confirming cellular integrity and intracellular compartmentalization of hemoglobin. For temperatures below 0°C, which are of particular interest for cryotherapy, the accuracy of a single temperature measurement was ±1°C, which is consistent with the clinical requirements. Validation of the proposed OA temperature imaging technique was performed for slow and fast cooling of blood samples embedded in tissue-mimicking phantoms. PMID:27822579

Dissociation of end systole from end ejection in patients with long-term mitral regurgitation.

PubMed

Brickner, M E; Starling, M R

1990-04-01

To determine whether left ventricular (LV) end systole and end ejection uncouple in patients with long-term mitral regurgitation, 59 patients (22 control patients with atypical chest pain, 21 patients with aortic regurgitation, and 16 patients with mitral regurgitation) were studied with micromanometer LV catheters and radionuclide angiograms. End systole was defined as the time of occurrence (Tmax) of the maximum time-varying elastance (Emax), and end ejection was defined as the time of occurrence of minimum ventricular volume (minV) and zero systolic flow as approximated by the aortic dicrotic notch (Aodi). The temporal relation between end systole and end ejection in the control patients was Tmax (331 +/- 42 [SD] msec), minV (336 +/- 36 msec), and then, zero systolic flow (355 +/- 23 msec). This temporal relation was maintained in the patients with aortic regurgitation. In contrast, in the patients with mitral regurgitation, the temporal relation was Tmax (266 +/- 49 msec), zero systolic flow (310 +/- 37 msec, p less than 0.01 vs. Tmax), and then, minV (355 +/- 37 msec, p less than 0.001 vs. Tmax and p less than 0.01 vs. Aodi). Additionally, the average Tmax occurred earlier in the patients with mitral regurgitation than in the control patients and patients with aortic regurgitation (p less than 0.01, for both), whereas the average time to minimum ventricular volume was similar in all three patient groups. Moreover, the average time to zero systolic flow also occurred earlier in the patients with mitral regurgitation than in the control patients (p less than 0.01) and patients with aortic regurgitation (p less than 0.05). Because of the dissociation of end systole from minimum ventricular volume in the patients with mitral regurgitation, the end-ejection pressure-volume relations calculated at minimum ventricular volume did not correlate (r = -0.09), whereas those calculated at zero systolic flow did correlate (r = 0.88) with the Emax slope values. We conclude that end ejection, defined as minimum ventricular volume, dissociates from end systole in patients with mitral regurgitation because of the shortened time to LV end systole in association with preservation of the time to LV end ejection due to the low impedance to ejection presented by the left atrium. Therefore, pressure-volume relations calculated at minimum ventricular volume might not be useful for assessing LV chamber performance in some patients with mitral regurgitation.

A predictive formula of the contraction stress in restorative and luting materials attending to free and adhered surfaces, volume and deformation.

PubMed

Miguel, A; de la Macorra, J C

2001-05-01

To find a predictive formula of stress, considering the surfaces (free, adhered) involved, the volume and characteristics of material and the deformation of the measuring system. 231 samples of five chemically cured restoratives (Silar (SIL, 23), Clearfil F2 (CLE, 39), P10 (P10, 33), Concise (CON, 30), Isopast (ISO, 28)) and four luting (3M Experimental 241 (EXM, 20), Variolink II (VAR, 13), Vitremer LC (VTM, 20) and Dyract Cem (DYR, 25)) materials were allowed to polymerize until they reached a maximum tension (T(max), 25 min) between six pairs (null 5.81, 8.5, 11.26, 12.42, 17.02, 23.14 mm) of polished metallic discs (range of distances: 0.02-5.9 mm) mounted in a tension machine. The deformation of the measuring system was measured for the recorded forces. A descriptive non-linear formula T(max)=KVol(-3.267)FS(3.283)AS(0.642)Def(0.561) was found that individualizes the material's characteristics (K) that considers volume (Vol), free (FS) and adhered (AS) surfaces and deformation (Def) of the system for each force. This formula renders good correlation (material K (r(2) coefficient)): SIL 0.9998 (0.995), CLE 1.0062 (0.989), P10 1.0224 (0.990), CON 0.9908 (0.992), ISO 0.9648 (0.974), EXM 1.0083 (0.991), VAR 0.9777 (0.996), VTM 0.9925 (0.993), DYR 0.9971 (0.997) between actual T(max) and calculated Tension. There are statistically significant differences (p=0.002) between K values of both (restorative and luting) groups. Predictive parameters have influence in a different way to what is actually considered, if the system is allowed to have deformation, as occurs naturally and volume and material's characteristics are considered.

Downscaling GCM Output with Genetic Programming Model

NASA Astrophysics Data System (ADS)

Shi, X.; Dibike, Y. B.; Coulibaly, P.

2004-05-01

Climate change impact studies on watershed hydrology require reliable data at appropriate spatial and temporal resolution. However, the outputs of the current global climate models (GCMs) cannot be used directly because GCM do not provide hourly or daily precipitation and temperature reliable enough for hydrological modeling. Nevertheless, we can get more reliable data corresponding to future climate scenarios derived from GCM outputs using the so called 'downscaling techniques'. This study applies Genetic Programming (GP) based technique to downscale daily precipitation and temperature values at the Chute-du-Diable basin of the Saguenay watershed in Canada. In applying GP downscaling technique, the objective is to find a relationship between the large-scale predictor variables (NCEP data which provide daily information concerning the observed large-scale state of the atmosphere) and the predictand (meteorological data which describes conditions at the site scale). The selection of the most relevant predictor variables is achieved using the Pearson's coefficient of determination ( R2) (between the large-scale predictor variables and the daily meteorological data). In this case, the period (1961 - 2000) is identified to represent the current climate condition. For the forty years of data, the first 30 years (1961-1990) are considered for calibrating the models while the remaining ten years of data (1991-2000) are used to validate those models. In general, the R2 between the predictor variables and each predictand is very low in case of precipitation compared to that of maximum and minimum temperature. Moreover, the strength of individual predictors varies for every month and for each GP grammar. Therefore, the most appropriate combination of predictors has to be chosen by looking at the output analysis of all the twelve months and the different GP grammars. During the calibration of the GP model for precipitation downscaling, in addition to the mean daily precipitation and daily precipitation variability for each month, monthly average dry and wet-spell lengths are also considered as performance criteria. For the cases of Tmax and Tmin, means and variances of these variables corresponding to each month were considered as performance criteria. The GP downscaling results show satisfactory agreement between the observed daily temperature (Tmax and Tmin) and the simulated temperature. However, the downscaling results for the daily precipitation still require some improvement - suggesting further investigation of other grammars. KEY WORDS: Climate change; GP downscaling; GCM.

A hot implantation study on the evolution of defects in He ion implanted MgO(1 0 0)

NASA Astrophysics Data System (ADS)

Fedorov, A. V.; van Huis, M. A.; van Veen, A.

2002-05-01

Ion implantation at elevated temperature, so-called hot implantation, was used to study nucleation and thermal stability of the defects. In this work, MgO(1 0 0) single crystal samples were implanted with 30 keV He ions at various implantation temperatures. The implantation doses ranged from 10 14 to 10 16 cm -2. The implantation introduced defects were subsequently studied by thermal helium desorption spectroscopy (THDS) and Doppler broadening positron beam analysis (PBA). The THDS study provides vital information on the kinetics of He release from the sample. PBA technique, being sensitive to the open volume defects, provides complementary information on cavity evolution. The THD study has shown that in most cases helium release is characterised by the activation energy of Q=4.7±0.5 eV with the maximum release temperature of Tmax=1830 K. By applying first order desorption model the pre-exponent factor is estimated as ν=4.3×10 11 s -1.

Magnetic field and pressure dependant resistivity behaviour of MnAs

NASA Astrophysics Data System (ADS)

Satya, A. T.; Amaladass, E. P.; Mani, Awadhesh

2018-04-01

The studies on the effect of magnetic field and external pressure on temperature dependant electrical resistivity behaviour of polycrystalline MnAs have been reported. At ambient pressure, ρ(T) shows a first order magnetic transition associated with change in sign of the temperature coefficient of resistivity from positive in the ferromagnetic (FM) phase to negative in the paramagnetic (PM) phase. The magneto resistance is negative and shows a peak at the FM transition temperature (T C ). The first order hysteresis width decreases with increase in magnetic field and the intersection of extrapolated linear variations of T C with field for the cooling and warming cycles enabled determination of the tricritical point. At high pressures, ρ(T) displays non monotonic variation exhibiting a low temperature minimum ({T}\\min L) and a high temperature maximum ({T}\\max H) accompanying broad thermal hysteresis above {T}\\min L. It is surmised that spin disorder scattering is responsible for the resistivity behaviour above {T}\\min L and the essential features of ρ(T) are qualitatively explained using Kasuya theoretical model. Below the {T}\\min L, ρ(T) follows linear logarithmic temperature dependence similar to the effect occurring due to Kondo type of scattering of conduction electrons with localised moments.

Modelling the delay between pharmacokinetics and EEG effects of morphine in rats: binding kinetic versus effect compartment models.

PubMed

de Witte, Wilhelmus E A; Rottschäfer, Vivi; Danhof, Meindert; van der Graaf, Piet H; Peletier, Lambertus A; de Lange, Elizabeth C M

2018-05-18

Drug-target binding kinetics (as determined by association and dissociation rate constants, k on and k off ) can be an important determinant of the kinetics of drug action. However, the effect compartment model is used most frequently instead of a target binding model to describe hysteresis. Here we investigate when the drug-target binding model should be used in lieu of the effect compartment model. The utility of the effect compartment (EC), the target binding kinetics (TB) and the combined effect compartment-target binding kinetics (EC-TB) model were tested on either plasma (EC PL , TB PL and EC-TB PL ) or brain extracellular fluid (ECF) (EC ECF , TB ECF and EC-TB ECF ) morphine concentrations and EEG amplitude in rats. It was also analyzed when a significant shift in the time to maximal target occupancy (Tmax TO ) with increasing dose, the discriminating feature between the TB and EC model, occurs in the TB model. All TB models assumed a linear relationship between target occupancy and drug effect on the EEG amplitude. All three model types performed similarly in describing the morphine pharmacodynamics data, although the EC model provided the best statistical result. The analysis of the shift in Tmax TO (∆Tmax TO ) as a result of increasing dose revealed that ∆Tmax TO is decreasing towards zero if the k off is much smaller than the elimination rate constant or if the target concentration is larger than the initial morphine concentration. The results for the morphine PKPD modelling and the analysis of ∆Tmax TO indicate that the EC and TB models do not necessarily lead to different drug effect versus time curves for different doses if a delay between drug concentrations and drug effect (hysteresis) is described. Drawing mechanistic conclusions from successfully fitting one of these two models should therefore be avoided. Since the TB model can be informed by in vitro measurements of k on and k off , a target binding model should be considered more often for mechanistic modelling purposes.

Estimating Finite Rate of Population Increase for Sharks Based on Vital Parameters

PubMed Central

Liu, Kwang-Ming; Chin, Chien-Pang; Chen, Chun-Hui; Chang, Jui-Han

2015-01-01

The vital parameter data for 62 stocks, covering 38 species, collected from the literature, including parameters of age, growth, and reproduction, were log-transformed and analyzed using multivariate analyses. Three groups were identified and empirical equations were developed for each to describe the relationships between the predicted finite rates of population increase (λ’) and the vital parameters, maximum age (Tmax), age at maturity (Tm), annual fecundity (f/Rc)), size at birth (Lb), size at maturity (Lm), and asymptotic length (L∞). Group (1) included species with slow growth rates (0.034 yr-1 < k < 0.103 yr-1) and extended longevity (26 yr < Tmax < 81 yr), e.g., shortfin mako Isurus oxyrinchus, dusky shark Carcharhinus obscurus, etc.; Group (2) included species with fast growth rates (0.103 yr-1 < k < 0.358 yr-1) and short longevity (9 yr < Tmax < 26 yr), e.g., starspotted smoothhound Mustelus manazo, gray smoothhound M. californicus, etc.; Group (3) included late maturing species (Lm/L∞ ≧ 0.75) with moderate longevity (Tmax < 29 yr), e.g., pelagic thresher Alopias pelagicus, sevengill shark Notorynchus cepedianus. The empirical equation for all data pooled was also developed. The λ’ values estimated by these empirical equations showed good agreement with those calculated using conventional demographic analysis. The predictability was further validated by an independent data set of three species. The empirical equations developed in this study not only reduce the uncertainties in estimation but also account for the difference in life history among groups. This method therefore provides an efficient and effective approach to the implementation of precautionary shark management measures. PMID:26576058

Assessing bioequivalence of generic modified-release antiepileptic drugs

PubMed Central

Chang, Yi-Ting; Davit, Barbara; Gidal, Barry E.; Krauss, Gregory L.

2016-01-01

Objectives: The purpose of this study was to determine how closely generic modified-release antiepileptic drugs (MR-AEDs) resemble reference (brand) formulations by comparing peak concentrations (Cmax), total absorption (area under the curve [AUC]), time to Cmax (Tmax), intersubject variability, and food effects between generic and reference products. Methods: We tabulated Cmax and AUC data from the bioequivalence (BE) studies used to support the approvals of generic Food and Drug Administration–approved MR-AEDs. We compared differences in 90% confidence intervals of the generic/reference AUC and Cmax geometric mean ratios, and intersubject variability, Tmax and delivery profiles and food effects. Results: Forty-two MR-AED formulations were studied in 3,175 healthy participants without epilepsy in 97 BE studies. BE ratios for AUC and Cmax were similar between most generic and reference products: AUC ratios varied by >15% in 11.4% of BE studies; Cmax varied by >15% in 25.8% of studies. Tmax was more variable, with >30% difference in 13 studies (usually delayed in the fed compared to fasting BE studies). Generic and reference MR products had similar intersubject variability. Immediate-release AEDs showed less intersubject variability in AUC than did MR-AEDs. Conclusions: Most generic and reference MR-AEDs have similar AUC and Cmax values. Ratios for some products, however, are near acceptance limits and Tmax values may vary. Food effects are common with MR-AED products. High variability in pharmacokinetic values for once-a-day MR-AEDs suggests their major advantage compared to immediate-release AED formulations may be the convenience of less frequent dosing to improve adherence. PMID:27016518

Systemic levels of local anaesthetic after intra-peritoneal application--a systematic review.

PubMed

Kahokehr, A; Sammour, T; Vather, R; Taylor, M; Stapelberg, F; Hill, A G

2010-07-01

There is a lack of cohesive reports on the systemic levels of local anaesthetic after intraperitoneal application. A comprehensive systematic review with no language restriction was conducted. Eighteen suitable articles were identified. Data were compiled and presented according to local anaesthetic agent. Intraperitoneal local anaesthetic has been studied in many different procedures, including open and laparoscopic surgery. A total of 415 patients were included for analysis. There were no cases of clinical toxicity. There were 11 (2.7%) cases with a systemic level above or close to a safe threshold (as determined by the report authors) in three trials utilising intraperitoneal local anaesthetic after laparoscopic cholecystectomy. Intraperitoneal lignocaine doses varied from 100 to 1000 mg, mean Cmax ranged from 1.01 to 4.32 microg/ml and mean Tmax ranged from 15 to 40 minutes. Intraperitoneal bupivacaine doses varied from 50 to 150 mg (weight based doses also reported), mean Cmax ranged from 0.29 to 1.14 microg/ml and mean Tmax ranged from 15 to 60 minutes. Intraperitoneal ropivacaine doses varied from 100 to 300 mg, mean Cmax ranged from 0.66 to 3.76 microg/ml and mean Tmax ranged from 15 to 35 minutes. The addition of adrenaline to intraperitoneal local anaesthetic almost halves systemic levels and prolongs Tmax. Intraperitoneal local anaesthetic results in detectable systemic levels in the perioperative setting. Despite a lack of clinical toxicity, careful attention to dose is still required to prevent potential systemic toxic levels. Clinicians should also consider the addition of adrenaline to intraperitoneal local anaesthetic solutions to further add to the systemic safety profile.

Lipophilicity affects the pharmacokinetics and toxicity of local anaesthetic agents administered by caudal block.

PubMed

Nava-Ocampo, Alejandro A; Bello-Ramírez, Angélica M

2004-01-01

1. Drugs administered into the epidural space by caudal block are cleared by means of a process potentially affected by the lipophilic character of the compounds. 2. In the present study, we examined the relationship between the octanol-water partition coefficient (log Poct) and the time to reach the maximum plasma drug concentration (tmax) of lignocaine, bupivacaine and ropivacaine administered by caudal block in paediatric patients. We also examined the relationship between log Poct and the toxicity of these local anaesthetic agents in experimental models. The tmax and toxicity data were obtained from the literature. 3. Ropivacaine, with a log Poct of 2.9, exhibited a tmax of 61.6 min. The tmax of lignocaine, with a log Poct of 2.4, and bupivacaine, with a log Poct of with 3.4, were approximately 50% shorter than ropivacaine. At log Poct of approximately 3.0, the toxicity of these local anaesthetic agents was substantially increased. The relationship between log Poct and the convulsive effect in dogs was similar to the relationship between log Poct and the lethal dose in sheep. 4. With local anaesthetic agents, it appears that the relationship between log Poct and drug transfer from the epidural space to the blood stream is parabolic, being the slowest rate of transference at log Poct 3.0. Toxicity, due to plasma availability of these local anaesthetic agents, seems to be increased at log Poct equal or higher than 3.0 secondary to the highest transfer from plasma into the central nervous system.

Evaluation of efficiency of insulin suppository formulations containing sodium salicylate or sodium cholate in insulin dependent diabetic patients.

PubMed

Hosny, Ehab A; Al-Marzouki, Zohair M H; Metwally, Mohammed E S; Souaida, Mamdouh Y S; Alshaik, Abdel Rhman A M

2003-10-01

Two formulations of insulin suppositories were prepared to contain different amounts of sodium salicylate and sodium cholate as absorption promoters and also of insulin with the purpose of obtaining the most effective formulation in reducing plasma glucose levels after rectal administration to diabetic patients. The results show that insulin suppositories containing 100 mg sodium salicylate and 100 or 200 U of crystalline insulin showed no significant difference in AUC, Cmax and Tmax and both formulations showed significant reduction in plasma glucose level compared to initial values within 1.5-2 h. The results from experiments carried out in health volunteers showed that 100 mg sodium salicylate is the optimum amount to be included in insulin suppositories producing significantly higher Cmax and AUC compared to those produced after rectal administration of insulin suppositories containing 50 or 200 mg sodium salicylate. The results also show that using sodium cholate in 50 mg amount did not produce any significant reduction in plasma glucose levels of insulin dependent diabetic patients given suppositories containing 100 U of insulin, but this amount in suppositories containing 200 U of insulin was able to produce significant (p < 0.05) reduction in plasma glucose level within 1 h which lasted till end of experiment producing Cmax of 29.7 +/- 6.61% at Tmax of 1.5 +/- 0.61 h. On increasing the amount of sodium cholate to 100 mg in the suppositories, a marked (p < 0.01) reduction in plasma glucose level took place and the Cmax increased to 47.7 +/- 12.24% at Tmax of 1.5 +/- 0.63 h. This resulted in AUC of 86.7 +/- 22.4 mg%h which was non significantly higher from that produced after administration of suppositories containing 50 mg sodium cholate and 200 U insulin (62.5 +/- 17.6 mg%h). The results also show that insulin suppositories containing 100 mg sodium cholate and 200 U insulin resulted in a non significant differences in Cmax and AUC from those produced by S.C. injection of insulin (20 U) but significantly (p < 0.001) shorter Tmax. This formulation also shows non significant differences in Tmax and AUC and significantly (p < 0.05) higher Cmax than from those produced after rectal administration of suppositories containing 100 mg of sodium salicylate and same amount of insulin. Further more this formulation produced severe hypoglycemia in control healthy volunteers within 1 h of administration producing Cmax of 57.0 +/- 18.8% at Tmax of 0.75 +/- 0.35 h. The results of this study showed that the formulation containing 100 mg of sodium cholate and 200 U of insulin tested in fasted insulin dependent diabetic patients produced a maximum % reduction in plasma glucose levels (Cmax) of 47.7 +/- 12.24% at tmax of 1.5 +/- 0.63 h compared to Cmax of 50.56 +/- 6.8% at tmax of 2.93 +/- 0.19 h resulted after subcutaneous injection of 20 U insulin. These suppositories produced an area under the curve (AUC) of 87 +/- 22.4 mg%h compared to an AUC of 81 +/- 13.4 mg%h obtained after subcutaneous injection. This formulation of suppositories studied in 7 insulin dependent diabetic patients was found to abolish the 2-h post-prandial significant rise in plasma glucose levels after meal. These results show that these insulin suppositories containing 100 mg of sodium cholate and 200 U of insulin can serve as effective buffer against meal related hyperglycemia. The suppositories were safe, effective, accepted and well tolerated by the tested individuals.

Carbon X-ray absorption in the local ISM: fingerprints in X-ray Novae spectra

NASA Astrophysics Data System (ADS)

Gatuzz, Efraín; Ness, J.-U.; Gorczyca, T. W.; Hasoglu, M. F.; Kallman, Timothy R.; García, Javier A.

2018-06-01

We present a study of the C K-edge using high-resolution LETGS Chandra spectra of four novae during their super-soft-source (SSS) phase. We identified absorption lines due to C II Kα, C III Kα and C III Kβ resonances. We used these astronomical observations to perform a benchmarking of the atomic data, which involves wavelength shifts of the resonances and photoionization cross-sections. We used improved atomic data to estimate the C II and C III column densities. The absence of physical shifts for the absorption lines, the consistence of the column densities between multiple observations and the high temperature required for the SSS nova atmosphere modeling support our conclusion about an ISM origin of the respective absorption lines. Assuming a collisional ionization equilibrium plasma the maximum temperature derived from the ratio of C II/C III column densities of the absorbers correspond to Tmax < 3.05 × 104 K.

Intramuscular and rectal therapies of acute seizures.

PubMed

Leppik, Ilo E; Patel, Sima I

2015-08-01

The intramuscular (IM) and rectal routes are alternative routes of delivery for antiepileptic drugs (AEDs) when the intravenous route is not practical or possible. For treatment of acute seizures, the AED used should have a short time to maximum concentration (Tmax). Some AEDs have preparations that may be given intramuscularly. These include the benzodiazepines (diazepam, lorazepam, and midazolam) and others (fosphenytoin, levetiracetam). Although phenytoin and valproate have parenteral preparations, these should not be given intramuscularly. A recent study of prehospital treatment of status epilepticus evaluated a midazolam (MDZ) autoinjector delivering IM drug compared to IV lorazepam (LZP). Seizures were absent on arrival to the emergency department in 73.4% of the IM MDZ compared to a 63.4% response in LZP-treated subjects (p < 0.001 for superiority). Almost all AEDs have been evaluated for rectal administration as solutions, gels, and suppositories. In a placebo-controlled study, diazepam (DZP) was administered at home by caregivers in doses that ranged from 0.2 to 0.5 mg/kg. Diazepam was superior to placebo in reduced seizure frequency in children (p < 0.001) and in adults (p = 0.02) and time to recurrent seizures after an initial treatment (p < 0.001). Thus, at this time, only MZD given intramuscularly and DZP given rectally appear to have the properties required for rapid enough absorption to be useful when intravenous routes are not possible. Some drugs cannot be administered rectally owing to factors such as poor absorption or poor solubility in aqueous solutions. The relative rectal bioavailability of gabapentin, oxcarbazepine, and phenytoin is so low that the current formulations are not considered to be suitable for administration by this route. When administered as a solution, diazepam is rapidly absorbed rectally, reaching the Tmax within 5-20 min in children. By contrast, rectal administration of lorazepam is relatively slow, with a Tmax of 1-2h. The dependence of gabapentin on an active transport system, and the much-reduced surface area of the rectum compared with the small intestine, may be responsible for its lack of absorption from the rectum. This article is part of a Special Issue entitled "Status Epilepticus". Copyright © 2015 Elsevier Inc. All rights reserved.

Improving the spatial accuracy in functional magnetic resonance imaging (fMRI) based on the blood oxygenation level dependent (BOLD) effect: benefits from parallel imaging and a 32-channel head array coil at 1.5 Tesla.

PubMed

Fellner, C; Doenitz, C; Finkenzeller, T; Jung, E M; Rennert, J; Schlaier, J

2009-01-01

Geometric distortions and low spatial resolution are current limitations in functional magnetic resonance imaging (fMRI). The aim of this study was to evaluate if application of parallel imaging or significant reduction of voxel size in combination with a new 32-channel head array coil can reduce those drawbacks at 1.5 T for a simple hand motor task. Therefore, maximum t-values (tmax) in different regions of activation, time-dependent signal-to-noise ratios (SNR(t)) as well as distortions within the precentral gyrus were evaluated. Comparing fMRI with and without parallel imaging in 17 healthy subjects revealed significantly reduced geometric distortions in anterior-posterior direction. Using parallel imaging, tmax only showed a mild reduction (7-11%) although SNR(t) was significantly diminished (25%). In 7 healthy subjects high-resolution (2 x 2 x 2 mm3) fMRI was compared with standard fMRI (3 x 3 x 3 mm3) in a 32-channel coil and with high-resolution fMRI in a 12-channel coil. The new coil yielded a clear improvement for tmax (21-32%) and SNR(t) (51%) in comparison with the 12-channel coil. Geometric distortions were smaller due to the smaller voxel size. Therefore, the reduction in tmax (8-16%) and SNR(t) (52%) in the high-resolution experiment seems to be tolerable with this coil. In conclusion, parallel imaging is an alternative to reduce geometric distortions in fMRI at 1.5 T. Using a 32-channel coil, reduction of the voxel size might be the preferable way to improve spatial accuracy.

Time required to achieve maximum concentration of amikacin in synovial fluid of the distal interphalangeal joint after intravenous regional limb perfusion in horses.

PubMed

Kilcoyne, Isabelle; Nieto, Jorge E; Knych, Heather K; Dechant, Julie E

2018-03-01

OBJECTIVE To determine the maximum concentration (Cmax) of amikacin and time to Cmax (Tmax) in the distal interphalangeal (DIP) joint in horses after IV regional limb perfusion (IVRLP) by use of the cephalic vein. ANIMALS 9 adult horses. PROCEDURES Horses were sedated and restrained in a standing position and then subjected to IVRLP (2 g of amikacin sulfate diluted to 60 mL with saline [0.9% NaCl] solution) by use of the cephalic vein. A pneumatic tourniquet was placed 10 cm proximal to the accessory carpal bone. Perfusate was instilled with a peristaltic pump over a 3-minute period. Synovial fluid was collected from the DIP joint 5, 10, 15, 20, 25, and 30 minutes after IVRLP; the tourniquet was removed after the 20-minute sample was collected. Blood samples were collected from the jugular vein 5, 10, 15, 19, 21, 25, and 30 minutes after IVRLP. Amikacin was quantified with a fluorescence polarization immunoassay. Median Cmax of amikacin and Tmax in the DIP joint were determined. RESULTS 2 horses were excluded because an insufficient volume of synovial fluid was collected. Median Cmax for the DIP joint was 600 μg/mL (range, 37 to 2,420 μg/mL). Median Tmax for the DIP joint was 15 minutes. CONCLUSIONS AND CLINICAL RELEVANCE Tmax of amikacin was 15 minutes after IVRLP in horses and Cmax did not increase > 15 minutes after IVRLP despite maintenance of the tourniquet. Application of a tourniquet for 15 minutes should be sufficient for completion of IVRLP when attempting to achieve an adequate concentration of amikacin in the synovial fluid of the DIP joint.

Tissue-Negative Transient Ischemic Attack: Is There a Role for Perfusion MRI?

PubMed

Grams, Raymond W; Kidwell, Chelsea S; Doshi, Amish H; Drake, Kendra; Becker, Jennifer; Coull, Bruce M; Nael, Kambiz

2016-07-01

Approximately 60% of patients with a clinical transient ischemic attack (TIA) do not have DWI evidence of cerebral ischemia. The purpose of this study was to assess the added diagnostic value of perfusion MRI in the evaluation of patients with TIA who have normal DWI findings. The inclusion criteria for this retrospective study were clinical presentation of TIA at admission with a discharge diagnosis of TIA confirmed by a stroke neurologist, MRI including both DWI and perfusion-weighted imaging within 48 hours of symptom onset, and no DWI lesion. Cerebral blood flow (CBF) and time to maximum of the residue function (Tmax) maps were evaluated independently by two observers. Multivariate analysis was used to assess perfusion findings; clinical variables; age, blood pressure, clinical symptoms, diabetes (ABCD2) score; duration of TIA; and time between MRI and onset and resolution of symptoms. Fifty-two patients (33 women, 19 men; age range, 20-95 years) met the inclusion criteria. A regional perfusion abnormality was identified on either Tmax or CBF maps of 12 of 52 (23%) patients. Seven (58%) of the patients with perfusion abnormalities had hypoperfused lesions best detected on Tmax maps; the other five had hyperperfusion best detected on CBF maps. In 11 of 12 (92%) patients with abnormal perfusion MRI findings, the regional perfusion deficit correlated with the initial neurologic deficits. Multivariable analysis revealed no significant difference in demographics, ABCD2 scores, or presentation characteristics between patients with and those without perfusion abnormalities. Perfusion MRI that includes Tmax and CBF parametric maps adds diagnostic value by depicting regions with delayed perfusion or postischemic hyperperfusion in approximately one-fourth of TIA patients who have normal DWI findings.

[Application of three heat pulse technique-based methods to determine the stem sap flow].

PubMed

Wang, Sheng; Fan, Jun

2015-08-01

It is of critical importance to acquire tree transpiration characters through sap flow methodology to understand tree water physiology, forest ecology and ecosystem water exchange. Tri-probe heat pulse sensors, which are widely utilized in soil thermal parameters and soil evaporation measurement, were applied to implement Salix matsudana sap flow density (Vs) measurements via heat-ratio method (HRM), T-Max method (T-Max) and single-probe heat pulse probe (SHPP) method, and comparative analysis was conducted with additional Grainer's thermal diffusion probes (TDP) measured results. The results showed that, it took about five weeks to reach a stable measurement stage after TPHP installation, Vs measured with three methods in the early stage after installation was 135%-220% higher than Vs in the stable measurement stage, and Vs estimated via HRM, T-Max and SHPP methods were significantly linearly correlated with Vs estimated via TDP method, with R2 of 0.93, 0.73 and 0.91, respectively, and R2 for Vs measured by SHPP and HRM reached 0.94. HRM had relatively higher precision in measuring low rates and reverse sap flow. SHPP method seemed to be very promising to measure sap flow for configuration simplicity and high measuring accuracy, whereas it couldn' t distinguish directions of flow. T-Max method had relatively higher error in sap flow measurement, and it couldn' t measure sap flow below 5 cm3 · cm(-2) · h(-1), thus this method could not be used alone, however it could measure thermal diffusivity for calculating sap flow when other methods were imposed. It was recommended to choose a proper method or a combination of several methods to measure stem sap flow, based on specific research purpose.

Kernel reconstruction methods for Doppler broadening - Temperature interpolation by linear combination of reference cross sections at optimally chosen temperatures

NASA Astrophysics Data System (ADS)

Ducru, Pablo; Josey, Colin; Dibert, Karia; Sobes, Vladimir; Forget, Benoit; Smith, Kord

2017-04-01

This article establishes a new family of methods to perform temperature interpolation of nuclear interactions cross sections, reaction rates, or cross sections times the energy. One of these quantities at temperature T is approximated as a linear combination of quantities at reference temperatures (Tj). The problem is formalized in a cross section independent fashion by considering the kernels of the different operators that convert cross section related quantities from a temperature T0 to a higher temperature T - namely the Doppler broadening operation. Doppler broadening interpolation of nuclear cross sections is thus here performed by reconstructing the kernel of the operation at a given temperature T by means of linear combination of kernels at reference temperatures (Tj). The choice of the L2 metric yields optimal linear interpolation coefficients in the form of the solutions of a linear algebraic system inversion. The optimization of the choice of reference temperatures (Tj) is then undertaken so as to best reconstruct, in the L∞ sense, the kernels over a given temperature range [Tmin ,Tmax ]. The performance of these kernel reconstruction methods is then assessed in light of previous temperature interpolation methods by testing them upon isotope 238U. Temperature-optimized free Doppler kernel reconstruction significantly outperforms all previous interpolation-based methods, achieving 0.1% relative error on temperature interpolation of 238U total cross section over the temperature range [ 300 K , 3000 K ] with only 9 reference temperatures.

Pharmacokinetics and bioequivalence of ranitidine and bismuth derived from two compound preparations

PubMed Central

Zhou, Quan; Ruan, Zou-Rong; Yuan, Hong; Jiang, Bo; Xu, Dong-Hang

2006-01-01

AIM: To evaluate the bioequivalence of ranitidine and bismuth derived from two compound preparations. METHODS: The bioavailability was measured in 20 healthy male Chinese volunteers following a single oral dose (equivalent to 200 mg of ranitidine and 220 mg of bismuth) of the test or reference products in the fasting state. Then blood samples were collected for 24 h. Plasma concentrations of ranitidine and bismuth were analyzed by high-performance liquid chromatography and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. The non-compartmental method was used for pharmacokinetic analysis. Log-transformed Cmax, AUC(0-t) and AUC(0-infinity) were tested for bioequivalence using ANOVA and Schuirmann two-one sided t-test. Tmax was analyzed by Wilcoxon’s test. RESULTS: Various pharmacokinetic parameters of ranitidine derived from the two compound preparations, including Cmax, AUC(0-t), AUC(0-infinity), Tmax and T1/2, were nearly consistent with previous observations. These parameters derived from test and reference drug were as follows: Cmax (0.67 ± 0.21 vs 0.68 ± 0.22 mg/L), AUC(0-t) (3.1 ± 0.6 vs 3.0 ± 0.7 mg/L per hour), AUC(0-infinity) (3.3 ± 0.6 vs 3.2 ± 0.8 mg/L per hour), Tmax (2.3 ± 0.9 vs 2.1 ± 0.9 h) and T1/2 (2.8 ± 0.3 vs 3.1 ± 0.4 h). In addition, double-peak absorption profiles of ranitidine were found in some Chinese volunteers. For bismuth, those parameters derived from test and reference drug were as follows: Cmax (11.80 ± 7.36 vs 11.40 ± 6.55 μg/L), AUC(0-t) (46.65 ± 16.97 vs 47.03 ± 21.49 μg/L per hour), Tmax (0.50 ± 0.20 vs 0.50 ± 0.20 h) and T1/2 (10.2 ± 2.3 vs 13.0 ± 6.9 h). Ninety percent of confidence intervals for the test/reference ratio of Cmax, AUC(0-t) and AUC(0-infinity) derived from both ranitidine and bismuth were found within the bioequivalence acceptable range of 80%-125%. No significant difference was found in Tmax derived from both ranitidine and bismuth. CONCLUSION: The two compound preparations are bioequivalent and may be prescribed interchangeably. PMID:16718762

An analysis of the moon's surface using reflected illumination from the earth during a waning crescent lunar phase

NASA Technical Reports Server (NTRS)

Hammond, Ernest C., Jr.; Linton-Petza, Maggie

1989-01-01

There have been many articles written concerning the lunar after-glow, the spectacular reflection from the moon's surface, and the possible observation of luminescence on the dark side of the moon. The researcher, using a 600 mm cassegrain telescope lense and Kodak 400 ASA T-Max film, photographed the crescent moon whose dark side was clearly visible by the reflected light from earth. The film was digitized to a Perkin-Elmer 1010M microdensitometer for enhancement and enlargement. The resulting pictures indicate a completely different land pattern formation than observed during a full moon. An attempt is made to analyze the observed structures and to compare them to the pictures observed during the normal full moon. There are boundaries on the digitized dark section of the moon that can be identified with structures seen during the normal full moon. But, these variations do change considerably under enhancement.

Thermal stability and degradation kinetics of kenaf/sol-gel silica hybrid

NASA Astrophysics Data System (ADS)

Yusof, F. A. M.; Hashim, A. S.; Tajudin, Z.

2017-12-01

Thermal stability and degradation kinetics of kenaf/sol-gel silica hybrid materials was investigated by thermogravimetric analysis (TGA). Model-free iso-conversion Flynn-Wall-Ozawa (FWO) and Coats-Redfern-modified (CRm) were chosen to evaluate the activation energy of the kenaf (KF) and kenaf/sol-gel silica (KFS) at heating rates (β) of 10, 20, 30 and 40 °C/min. The results shows that an apparent activation energy was increased for the kenaf/sol-gel silica hybrid (211.59 kJ/mol for FWO and 191.55 kJ/mol for CRm) as compared to kenaf fiber (202.84 kJ/mol for FWO and 186.20 kJ/mol for CRm). Other parameters such as integral procedure decomposition temperature (IPDT), final residual weight (Rf), temperature of maximum degradation rate (Tmax) and residual at maximum temperature (RTmax) were obtained from TGA curves, additionally confirmed the thermal stability of the kenaf/sol-gel silica hybrid. These activation energy values and other findings developed the simplified approach in order to understand the thermal stability and degradation kinetics behavior of kenaf/sol-gel silica hybrid materials.

Crystal growth, structural, low temperature thermoluminescence and mechanical properties of cubic fluoroperovskite single crystal (LiBaF3)

NASA Astrophysics Data System (ADS)

Daniel, D. Joseph; Ramasamy, P.; Ramaseshan, R.; Kim, H. J.; Kim, Sunghwan; Bhagavannarayana, G.; Cheon, Jong-Kyu

2017-10-01

Polycrystalline compounds of LiBaF3 were synthesized using conventional solid state reaction route and the phase purity was confirmed using powder X-ray diffraction technique. Using vertical Bridgman technique single crystal was grown from melt. Rocking curve measurements have been carried out to study the structural perfection of the grown crystal. The single peak of diffraction curve clearly reveals that the grown crystal was free from the structural grain boundaries. The low temperature thermoluminescence of the X-ray irradiated sample has been analyzed and found four distinguishable peaks having maximum temperatures at 18, 115, 133 and 216 K. Activation energy (E) and frequency factor (s) for the individual peaks have been studied using Peak shape method and the computerized curve fitting method combining with the Tmax- TStop procedure. Nanoindentation technique was employed to study the mechanical behaviour of the crystal. The indentation modulus and Vickers hardness of the grown crystal have values of 135.15 GPa and 680.81 respectively, under the maximum indentation load of 10 mN.

Influence of stem temperature changes on heat pulse sap flux density measurements.

PubMed

Vandegehuchte, Maurits W; Burgess, Stephen S O; Downey, Alec; Steppe, Kathy

2015-04-01

While natural spatial temperature gradients between measurement needles have been thoroughly investigated for continuous heat-based sap flow methods, little attention has been given to how natural changes in stem temperature impact heat pulse-based methods through temporal rather than spatial effects. By modelling the theoretical equation for both an ideal instantaneous pulse and a step pulse and applying a finite element model which included actual needle dimensions and wound effects, the influence of a varying stem temperature on heat pulse-based methods was investigated. It was shown that the heat ratio (HR) method was influenced, while for the compensation heat pulse and Tmax methods changes in stem temperatures of up to 0.002 °C s(-1) did not lead to significantly different results. For the HR method, rising stem temperatures during measurements led to lower heat pulse velocity values, while decreasing stem temperatures led to both higher and lower heat pulse velocities, and to imaginary results for high flows. These errors of up to 40% can easily be prevented by including a temperature correction in the data analysis procedure, calculating the slope of the natural temperature change based on the measured temperatures before application of the heat pulse. Results of a greenhouse and outdoor experiment on Pinus pinea L. show the influence of this correction on low and average sap flux densities. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Antipyretic Therapy in Critically Ill Patients with Sepsis: An Interaction with Body Temperature

PubMed Central

Zhang, Zhongheng; Chen, Lin; Ni, Hongying

2015-01-01

Background and Objective The effect of antipyretic therapy on mortality in patients with sepsis remains undetermined. The present study aimed to investigate the role of antipyretic therapy in ICU patients with sepsis by using a large clinical database. Methods The multiparameter intelligent monitoring in intensive care II (MIMIC- II) database was employed for the study. Adult patients with sepsis were included for analysis. Antipyretic therapy included antipyretic medication and external cooling. Multivariable model with interaction terms were employed to explore the association of antipyretic therapy and mortality risk. Main Results A total of 15,268 patients fulfilled inclusion criteria and were included in the study. In multivariable model by treating temperature as a continuous variable, there was significant interaction between antipyretic therapy and the maximum temperature (Tmax). While antipyretic therapy had no significant effect on mortality in low temperature quintiles, antipyretic therapy was associated with increased risk of death in the quintile with body temperature >39°C (OR: 1.29, 95% CI: 1.04–1.61). Conclusion Our study shows that there is no beneficial effect on reducing mortality risk with the use of antipyretic therapy in ICU patients with sepsis. External cooling may even be harmful in patients with sepsis. PMID:25822614

Brain delivery of buspirone hydrochloride chitosan nanoparticles for the treatment of general anxiety disorder.

PubMed

Bari, Naimat Kalim; Fazil, Mohammad; Hassan, Md Quamrul; Haider, Md Rafi; Gaba, Bharti; Narang, Jasjeet K; Baboota, Sanjula; Ali, Javed

2015-11-01

The present work discusses the preparation, characterization and in vivo evaluation of thiolated chitosan nanoparticles (TCS-NPs) of buspirone hydrochloride (BUH) for brain delivery through intranasal route. TCS NPs were prepared by ionic gelation method and characterized for various parameters. The NPs formed were having particle size of 226.7±2.52nm with PDI 0.483±0.031. Drug entrapment efficiency (EE) and loading capacity (LC) were found to be 81.13±2.8 and 49.67±5.5%. The cumulative percentage drug permeation through nasal mucosa was 76.21%. Bioadhesion study carried out on porcine mucin and showed a bioadhesion efficiency of 90.218±0.134%. Nose-to-brain delivery of placebo NPs was investigated by confocal laser scanning microscopy (CLSM) technique using rhodamine-123 as a marker. The brain concentration achieved after intranasal administration of TCS-NPs was 797.46±35.76ng/ml with tmax 120min which was significantly higher than achieved after intravenous administration on BUH solution 384.15±13.42ng/ml and tmax of 120min and intranasal administration of BUH solution 417.77±19.24ng/ml and tmax 60min. Copyright © 2015 Elsevier B.V. All rights reserved.

Inhibitory activity of aspirin on von Willebrand factor-induced platelet aggregation.

PubMed

Homoncik, M; Jilma, B; Eichelberger, B; Panzer, S

2000-09-01

The effect of aspirin (ASA) on vWF induced platelet - platelet interaction is unknown. We therefore tested the response of platelets to von Willebrand factor (vWF) coated beads induced platelet aggregation before and after i.v. and oral ASA. 1000 mg ASA was infused to 10 healthy individuals and after a wash-out period 7 volunteers received 100 mg ASA orally over a period of 11 days. Prior to ASA and in regular intervals thereafter we tested the reactivity to vWF-coated beads to assess platelet adhesion/aggregation and the fade-out time of ASA effects on platelets. Considerable interindividual variability in response to vWF-coated beads was observed, both before ASA and after treatment with ASA. The maximal response to vWF-coated beads (Tmax), the time lag, and the slope of the curve were significantly affected by i.v. ASA, whereas 100 mg of ASA had only inconstant effect on Tmax and slope. The absolute reduction of Tmax after ASA depended on the pre-ASA level, while the percentage of the reduction was similar in all individuals. Thus, platelet aggregation induced by vWF-coated beads is impaired by ASA. Furthermore, our data indicate a large interindividual variability of the response to ASA shortly after treatment induction, which becomes more constant after prolonged treatment.

Large Electrocaloric Effect in Lead-Free (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 Ceramics Prepared via Citrate Route

PubMed Central

Shi, Jing; Zhu, Rongfeng; Liu, Xing; Yuan, Ningyi; Ding, Jianning; Luo, Haosu

2017-01-01

The 1 wt % Li-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT-Li) ceramics prepared by the citrate method exhibit improved phase purity, densification and electrical properties, which provide prospective possibility to develop high-performance electrocaloric materials. The electrocaloric effect was evaluated by phenomenological method, and the BCZT-Li ceramics present large electrocaloric temperature change ∆T, especially large electrocaloric responsibility ξ = ∆Tmax/∆Emax, which can be comparable to the largest values reported in the lead-free piezoelectric ceramics. The excellent electrocaloric effect is considered as correlating with the coexistence of polymorphic ferroelectric phases, which are detected by the Raman spectroscopy. The large ξ value accompanied by decreased Curie temperature (around 73 °C) of the BCZT-Li ceramics prepared by the citrate method presents potential applications as the next-generation solid-state cooling devices. PMID:28927004

Responses of catecholestrogen metabolism to acute graded exercise in normal menstruating women before and after training.

PubMed

De Crée, C; Ball, P; Seidlitz, B; Van Kranenburg, G; Geurten, P; Keizer, H A

1997-10-01

It has been hypothesized that exercise-related hypo-estrogenemia occurs as a consequence of increased competition of catecholestrogens (CE) for catechol-O-methyltransferase (COMT). This may result in higher norepinephrine (NE) concentrations, which could interfere with normal gonadotropin pulsatility. The present study investigates the effects of training on CE responses to acute exercise stress. Nine untrained eumenorrheic women (mean percentage of body fat +/-SD: 24.8 +/- 3.1%) volunteered for an intensive 5-day training program. Resting, submaximal, and maximal (tmax) exercise plasma CE, estrogen, and catecholamine responses were determined pre- and post training in both the follicular (FPh) and luteal phase (LPh). Acute exercise stress increased total primary estrogens (E) but had little effect on total 2-hydroxyestrogens (2-OHE) and 2-hydroxyestrogen-monomethylethers (2-MeOE) (= O-methylated CE after competition for catechol-O-methyltransferase). This pattern was not significantly changed by training. However, posttraining LPh mean (+/-SE) plasma E, 2-OHE, and 2-MeOE concentrations were significantly lower (P < 0.05) at each exercise intensity (for 2-OHE: 332 +/- 47 vs. 422 +/- 57 pg/mL at tmax; for 2-MeOE: 317 +/- 26 vs. 354 +/- 34 pg/mL at tmax). Training produced opposite effects on 2-OHE:E ratios (an estimation of CE formation) during acute exercise in the FPh (reduction) and LPh (increase). The 2-MeOE:2-OHE ratio (an estimation of CE activity) showed significantly higher values at tmax in both menstrual phases after training (FPh: +11%; LPh: +23%; P < 0.05). After training, NE values were significantly higher (P < 0.05). The major findings of this study were that: training lowers absolute concentrations of plasma estrogens and CE; the acute exercise challenge altered plasma estrogens but had little effect on CE; estimation of the formation and activity of CE suggests that formation and O-methylation of CE proportionately increases. These findings may be of importance for NE-mediated effects on gonadotropin release.

A pharmacokinetic study of two modified-release methylphenidate formulations under different food conditions in healthy volunteers.

PubMed

Haessler, F; Tracik, F; Dietrich, H; Stammer, H; Klatt, J

2008-09-01

Primary objective was to investigate bioequivalence of Ritalin LA(R); 40 mg compared to Medikinet retard 40 mg in healthy male volunteers under fasted and fed conditions. Secondary objectives included assessment of tolerability and determination of further pharmacokinetic parameters. The difference between the kinetic profiles of Ritalin LA(R) and Medikinet retard with respect to breakfast intake was additionally explored. 28 subjects were randomized in this open-label, four-treatment, cross-over-design study. Pharmacokinetic evaluations included AUC(0-inf), Cmax, tmax, elimination half life (t1/2) and mean residence time MRT(0-inf)). The relative bioavailability of Ritalin LA(R) and Medikinet retard and the food effect were assessed using a 90% confidence interval (CI) based on the lower and upper endpoints of the CI for the ratios of the geometric means being within the 80 - 125% equivalence criterion. 25 volunteers completed all treatment arms. Frequency of adverse events were comparable for all treatments. Under fasted condition Ritalin LA(R) showed a consistent bimodal concentration time profile with two tmax peaks. Medikinet retard showed a steady absorption with a single tmax peak. The point estimators for AUC(0-inf) and Cmax were found to be 99.7% and 85.9%, respectively. Under fed condition both Ritalin LA(R) and Medikinet retard showed a bimodal concentration time profile with two tmax peaks. The point estimators for AUC(0-inf) and Cmax were estimated as 89.8% and 68.6%, respectively. Both methylphenidate formulations were safe and well tolerated. Ritalin LA and Medikinet retard were bioequivalent in fasted state but not in fed state. Only Ritalin LA had a biphasic kinetic profile under both fasted and fed conditions. This difference in the kinetic profiles might be of clinical relevance and might offer a potential advantage of Ritalin LA.

Gd-EOB-DTPA-enhanced-MR imaging in the inflammation stage of nonalcoholic steatohepatitis (NASH) in mice.

PubMed

Yamada, Tomomi; Obata, Atsushi; Kashiwagi, Yuto; Rokugawa, Takemi; Matsushima, Shuuichi; Hamada, Tadateru; Watabe, Hiroshi; Abe, Kohji

2016-07-01

The purpose of this study is to investigate the correlation between the liver kinetics of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) and liver histopathology in a mouse model of NASH by using dynamic contrast-enhanced MRI. Twenty male C57/BL6 mice aged 8weeks were fed a methionine-choline-deficient (MCD) diet for 2, 4 and 6weeks (MCD groups: MCD 2w, 4w, or 6w). Gd-EOB-DTPA-enhanced MR imaging of the liver was performed at 2, 4 and 6weeks after the MCD feeding. The signal intensity of the liver was obtained from dynamic MR images and relative enhancement (RE), and the time to maximum RE (Tmax) and half-life of elimination RE (T1/2) were calculated. After MRI scan, histopathological scores of hepatic steatosis and inflammation and blood biochemistry data, such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, were obtained. Plasma AST and ALT levels were significantly increased in mice fed MCD. Histopathological scores indicated that steatohepatitis progressed with the MCD feeding period from 2 to 6weeks, but significant fibrosis was observed only in mice fed MCD for 6weeks. Gd-EOB-DTPA-enhanced MRI showed that Tmax was significantly prolonged in the livers of the 6-week group compared to the control group (control, 4.0±0.7min; MCD 6w, 12.1±1.6min), although there was no alteration in the 2- and 4-week groups. T1/2 was significantly prolonged in mice fed MCD for 4 and 6weeks compared to the control group (control, 19.9±2.0min; MCD 4w, 46.7±8.7min; MCD 6w, 65.4±8.8min). The parameters of Gd-EOB-DTPA kinetics (Tmax and T1/2) in the liver were positively correlated with the liver histopathological score (steatosis vs Tmax, rho=0.69, P=0.0007; inflammation vs Tmax, rho=0.66, P=0.00155; steatosis vs T1/2, rho=0.77, P<0.0001; inflammation vs T1/2, rho=0.73, P=0.0003). The liver kinetics of Gd-EOB-DTPA correlated well with the inflammation score in the mouse model of NASH, suggesting the possibility of detecting the steatohepatitis stage without fibrosis by Gd-EOB-DTPA-enhanced MR imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

Thermal explosion analysis of methyl ethyl ketone peroxide by non-isothermal and isothermal calorimetric applications.

PubMed

Chi, Jen-Hao; Wu, Sheng-Hung; Shu, Chi-Min

2009-11-15

In the past, process incidents attributed to organic peroxides (OPs) that involved near misses, over-pressures, runaway reactions, and thermal explosions occurred because of poor training, human error, incorrect kinetic assumptions, insufficient change management, and inadequate chemical knowledge in the manufacturing process. Calorimetric applications were employed broadly to test organic peroxides on a small-scale because of their thermal hazards, such as exothermic behavior and self-accelerating decomposition in the laboratory. In essence, methyl ethyl ketone peroxide (MEKPO) is highly reactive and exothermically unstable. In recent years, it has undergone many thermal explosions and runaway reaction incidents in the manufacturing process. Differential scanning calorimetry (DSC), vent sizing package 2 (VSP2), and thermal activity monitor (TAM) were employed to analyze thermokinetic parameters and safety index. The intent of the analyses was to facilitate the use of various auto-alarm equipments to detect over-pressure, over-temperature, and hazardous materials leaks for a wide spectrum of operations. Results indicated that MEKPO decomposition is detected at low temperatures (30-40 degrees C), and the rate of decomposition was shown to exponentially increase with temperature and pressure. Determining time to maximum rate (TMR), self-accelerating decomposition temperature (SADT), maximum temperature (T(max)), exothermic onset temperature (T(0)), and heat of decomposition (DeltaH(d)) was essential for identifying early-stage runaway reactions effectively for industries.

Diagenesis of Upper Carboniferous rocks in the Ouachita foreland shelf in mid-continent USA: an overview of widespread effects of a Variscan-equivalent orogeny

USGS Publications Warehouse

Walton, A.W.; Wojcik, K.M.; Goldstein, R.H.; Barker, C.E.

1995-01-01

Diagenesis of Upper Carboniferous foreland shelf rocks in southeastern Kansas took place at temperatures as high as 100-150?? C at a depth of less than 2 km. High temperatures are the result of the long distance (hundreds of kilometers) advection of groundwater related to collisional orogeny in the Ouachita tectonic belt to the south. Orogenic activity in the Ouachita area was broadly Late Carboniferous, equivalent to the Variscan activity of Europe. Mississippi Valley-type Pb-Zn deposits and oil and gas fields in the US midcontinent and elsewhere are commonly attributed to regional groundwater flow resulting from such collisional events. This paper describes the diagenesis and thermal effects in sandstone and limestone of Upper Carboniferous siliciclastic and limestone-shale cyclothems, the purported confining layer of a supposed regional aquifer. Diagenesis took place in early, intermediate, and late stages. Many intermediate and late stage events in the sandstones have equivalents in the limestones, suggesting that the causes were regional. The sandstone paragenesis includes siderite cement (early stage), quartz overgrowths (intermediate stage), dissolution of feldspar and carbonates, followed by minor Fe calcite, pore-filling kaolinite and sub-poikilotopic Ca ankerite (late stage). The limestone paragenesis includes calcite cement (early stage); megaquartz, chalcedony, and Fe calcite spar (intermediate stage); and dissolution, Ca-Fe dolomite and kaolinite (late stage). The Rm value of vitrinite shows a regional average of 0.6-0.7%; Rock-Eval TmaX suggests a comparable degree of organic maturity. The Th of aqueous fluid inclusions in late stage Ca-Fe-Mg carbonates ranges from 90 to 160?? and Tmice indicates very saline water (>200000 ppm NaCl equivalent); ??18O suggests that the water is of basinal origin. Local warm spots have higher Rm, Tmax, and Th. The results constrain numerical models of regional fluid migration, which is widely viewed as an artesian flow from recharge areas in the Ouachita belt across the foreland basin onto the foreland shelf area. Such models must account for heating effects that extend at least 500 km from the orogenic front and affect both supposed aquifer beds and the overlying supposed confining layer. Warm spots indicate either more rapid or more prolonged flow locally. Th and Tmice data show the highest temperatures coincided with high salinity fluids. ?? 1995 Springer-Verlag.

Weather types and strokes in the Augsburg region (Southern Germany)

NASA Astrophysics Data System (ADS)

Beck, Christoph; Ertl, Michael; Giemsa, Esther; Jacobeit, Jucundus; Naumann, Markus; Seubert, Stefanie

2017-04-01

Strokes are one of the leading causes of morbidity and mortality worldwide and the main reason for longterm care dependency in Germany. Concerning the economical impact on patients and healthcare systems it is of particular importance to prevent this disease as well as to improve the outcome of the affected persons. Beside the primary well-known risk factors like hypertension, cigarette smoking, physical inactivity and others, also weather seems to have pronounced influence on the occurrence and frequency of strokes. Previous studies most often focused on effects of singular meteorological variables like ambient air temperature, air pressure or humidity. An advanced approach is to link the entire suite of daily weather elements classified to air mass- or weather types to cerebrovascular morbidity or mortality. In a joint pilot study bringing together climatologists, environmental scientists and physicians from the University of Augsburg and the clinical centre Augsburg, we analysed relationships between singular meteorological parameters as well as combined weather effects (e.g. weather types) and strokes in the urban area of Augsburg and the surrounding rural region. A total of 17.501 stroke admissions to Neurological Clinic and Clinical Neurophysiology at Klinikum Augsburg between 2006 and 2015 are classified to either "ischaemic" (16.354) or "haemorrhagic" (1.147) subtype according to etiology (based on the International Classification of Diseases - 10th Revision). Spearman correlations between daily frequencies of ischaemic and haemorrhagic strokes and singular atmospheric parameters (T, Tmin, Tmax, air pressure, humidity etc.) measured at the DWD (German weather service) meteorological station at Augsburg Muehlhausen are rather low. However, higher correlations are achieved when considering sub-samples of "homogenous weather conditions" derived from synoptic circulation classifications: e.g. within almost all of 10 types arising from a classification of central European mean sea level pressure fields into "Großwettertypes" (Beck 2000) the relationships between meteorological variables and stroke frequencies are increasing. Mainly temperature variables (Tmin, Tmax, Tmean) appear to be important particularly in winter and summer. Moreover distinct correlations of similar magnitude are obtained with other variables like wind speed or precipitation for specific weather types (e.g. westerly type). In how far these initial findings do really point to additional health impacts beyond temperature effects is subject of ongoing work.

Physical efficiency of Bengali farmers in response to change in environmental factors.

PubMed

Chandra, A M; Mahanta, S; Sadhu, N

1994-06-01

The present study was conducted on young farmers, selected randomly from a village of West Bengal. Their pre-exercise heart rate (HR), blood pressure (BP), mean arterial pressure (MAP), and other physical parameters were recorded. They were asked to perform standard step test at four different times of a day when environmental factors were recorded. Recorded environmental factors were maximum ambient temperature (Tmax), and minimum ambient temperature (Tmin) for the whole day, ambient temperature (Ta), relative humidity (RH), air velocity (AV), and globe temperature (Tg). The barometric pressure (P) was noted to be constant throughout the experiment. Post-exercise HR and MAP were also recorded. Our observations showed that environmental factors changed as the day progressed from the morning to noon and from noon to night; the physiological parameters of the farmers also changed. HR was lowest in the morning and night but highest in the evening while MAP was highest at midday and gradually returned to the pre-exercise level by the evening. The determined Physical Fitness Index (PFI) of the farmers was noted to be lowest at midday but highest at night. Our studies indicate that environmental factors have a role on the physical efficiency of farmers. Ta, RH and Tg appear to be primarily responsible for the alterations in the physiological functions and PFI.

Fetal origin of the posterior cerebral artery produces left-right asymmetry on perfusion imaging.

PubMed

Wentland, A L; Rowley, H A; Vigen, K K; Field, A S

2010-03-01

Fetal origin of the PCA is a common anatomic variation of the circle of Willis. On perfusion imaging, patients with unilateral fetal-type PCA may demonstrate left-right asymmetry that could mimic cerebrovascular disease. The aim of this study was to characterize the relationship between a fetal-type PCA and asymmetry of hemodynamic parameters derived from MR perfusion imaging. We retrospectively reviewed MR perfusion studies of 36 patients to determine the relationship between hemodynamic and vascular asymmetries in the PCA territory. Perfusion asymmetry indices for the PCA territory were computed from maps of rCBF, rCBV, MTT, T(max), and FMT. Vascular asymmetry indices were derived from calibers of the PCA-P1 segments relative to the posterior communicating arteries. Asymmetrically smaller values of FMT and T(max) were observed with unilateral fetal-type PCA, and these were strongly correlated with the degree of vascular asymmetry (Spearman's rho = 0.76 and 0.74, respectively, P < 1 x 10(-6)). Asymmetries of rCBF, MTT, and rCBV were neither significant nor related to vascular asymmetry. Faster perfusion transit times are seen for parameters sensitive to macrovascular transit effects (eg, FMT and T(max)) ipsilateral to fetal origin of the PCA in proportion to the degree of arterial asymmetry. Knowledge of this normal variation is critical in the interpretation of perfusion studies because asymmetry could mimic cerebrovascular pathology.

Growth and reproduction of the mangrove crab Goniopsis cruentata (Latreille, 1803) (Crustacea: Decapoda: Grapsidae) in southeastern Brazil.

PubMed

Reis, Carla R G; Taddei, Fabiano G; Cobo, Valter J

2015-01-01

Goniopsis cruentata is a common semi-terrestrial crab in Brazilian mangroves and an important fishery resource for traditional communities in the northeastern Brazilian coast. Aiming to contribute to the knowledge about the species, this study evaluated the carapace width and weight growth curves, the relative growth of weight versus carapace width, and the temporal variation of gonadosomatic and hepatosomatic indices for the species. A total of 524 crabs were collected in a mangrove area of Ubatuba municipality, state of São Paulo. The growth-curves parameters and longevity (tmax) were estimated for males (CW∞=50.6 mm, WE=56.4 g, k=2.24, t0=0.003631502 year-1, tmax=1.3 years) and females (CW∞=50.7 mm, WE∞=58.8 g, k=2.50, t0=0.003247209 year-1, tmax=1.2 years). The age at onset of sexual maturity was 0.23 years for both genders. The weight-growth model was isometric for the immature developmental stages and allometric negative for adults. The species exhibited a continuous reproduction, with breeding peaks in spring and summer months. The weight dynamics of gonads and hepatopancreas were not clearly related. The growth and reproductive patterns indicated that Goniopsis cruentata has a life-history that prioritizes reproduction instead of survival. The species exhibited some of the highest growth rates and lowest longevity estimates reported for brachyuran species in Brazil.

The 2016 southeastern US drought: an extreme departure from centennial wetting and cooling

NASA Astrophysics Data System (ADS)

Williams, P.; Cook, B. I.; Smerdon, J. E.; Bishop, D. A.; Seager, R.; Mankin, J. S.

2017-12-01

The southeastern United States (SE US) drought in fall 2016 appeared exceptional based on its wildfire and water-supply impacts but the current monitoring framework does not readily facilitate evaluation of moisture-balance anomalies in a centennial context. A new method to extend modeled soil-moisture records back to 1895 is developed using monthly climate data. Since 1895, October-November 2016 soil moisture (0-200 cm) in the SE US was likely the second lowest on record, behind 1954. This severe drought developed rapidly and was brought on by near record-low September-November precipitation and record-high September-November daily maximum temperatures (Tmax). Record Tmax drove record-high atmospheric moisture demand, accounting for 28% of the October-November 2016 soil-moisture anomaly. Drought and heat in fall 2016 contrasted strongly with 20th-century wetting and cooling trends, with few analogs after the mid-1950s. Dynamically, the exceptional drying in fall 2016 was driven by anomalous ridging over the central United States that reduced south-southwesterly moisture transports into the SE US by approximately 75%. These circulation anomalies were promoted by moderate La Niña conditions and warmth in the tropical North Atlantic, but these processes did not account for a majority of the SE US drying in fall 2016 and therefore imply a large role for internal atmospheric variability. The extended analysis back to 1895 indicates that SE US droughts as strong as the 2016 event are more likely than indicated from a shorter 60-year perspective, and continued multi-decadal swings in precipitation may combine with future warming to further enhance the likelihood of such events.

Nuclear pasta in hot dense matter and its implications for neutrino scattering

NASA Astrophysics Data System (ADS)

Roggero, Alessandro; Margueron, Jérôme; Roberts, Luke F.; Reddy, Sanjay

2018-04-01

The abundance of large clusters of nucleons in neutron-rich matter at subnuclear density is found to be greatly reduced by finite-temperature effects when matter is close to β equilibrium, compared to the case where the electron fraction is fixed at Ye>0.1 , as often considered in the literature. Large nuclei and exotic nonspherical nuclear configurations called pasta, favored in the vicinity of the transition to uniform matter at T =0 , dissolve at a relatively low temperature Tu as protons leak out of nuclei and pasta. For matter at β equilibrium with a negligible neutrino chemical potential we find that Tuβ≃4 ±1 MeV for realistic equations of state. This is lower than the maximum temperature Tmaxβ≃9 ±1 MeV at which nuclei can coexist with a gas of nucleons and can be explained by a change in the nature of the transition to uniform matter called retrograde condensation. An important new finding is that coherent neutrino scattering from nuclei and pasta makes a modest contribution to the opacity under the conditions encountered in supernovas and neutron star mergers. This is because large nuclear clusters dissolve at most relevant temperatures, and at lower temperatures, when clusters are present, Coulomb correlations between them suppress coherent neutrino scattering off individual clusters. Implications for neutrino signals from galactic supernovas are briefly discussed.

Comparative bioavailability of different formulations of levothyroxine and liothyronine in healthy volunteers.

PubMed

Leggio, G M; Incognito, T; Privitera, G; Marano, M R; Drago, F

2006-12-01

To evaluate the relative bioavailability of T4 sodium and liothyronine sodium (T3), administered in single doses as oral solution (drops) and tablet forms, according to two separate study protocols. Twenty-four healthy, male volunteers were included in both studies. Two test drugs containing T4 or T3 (T4-Ibsa and T3-Ibsa, respectively) were compared to two reference drugs, ie Eutirox 100 and Ti-tre tablets, respectively. A single oral dose of 100 microg (1 ml or 1 tablet) of T4 and 20 microg (1 ml or 1 tablet) of T3 were administered with an open, randomized, crossover design. T4 and T3 serum concentrations were determined by a validated immunoassay in electro-chemo-luminescence method. Study 1: after administration of T4-Ibsa oral solution, Cmax was 14.26+/-0.61 microg/dl, AUC0-t was 282.70 +/-14.29 microg/dl/h, Tmax was 2.71+/-0.25 h. After administration of Eutirox 100 tablets, Cmax was 14.34+/-0.59 microg/dl, AUC0-t was 279.42+/-9.59 microg/dl/h and Tmax was 2.65+/-0.23 h. The 90% confidence interval ratios between test/reference drugs were 1.01 for AUC0-t and 0.99 for Cmax. Study 2: after administration of T3-Ibsa oral solution, Cmax was 3.19+/-0.25 ng/ml, AUC0-t was 44.79+/-2.15 ng/ml/h and Tmax was 2.31+/-0.25 h. After administration of Ti-tre tablets, Cmax was 3.16+/-0.23 ng/ml, AUC0-t was 45.19+/-2.19 ng/ml/h and Tmax was 2.44+/-0.34 h. The 90% confidence interval ratios between test /reference drugs were 0.99 for AUC0-t and 1.01 for Cmax. The bioavailability of the two oral solutions (T4-Ibsa and T3-Ibsa oral solutions) and the corresponding tablet forms (Eutirox 100 and Ti-tre tablets) were confirmed and they can be considered bioequivalent and therapeutically interchangeable.

Pharmacokinetics of Lidocaine With Epinephrine Following Local Anesthesia Reversal With Phentolamine Mesylate

PubMed Central

Moore, Paul A; Hersh, Elliot V; Papas, Athena S; Goodson, J. Max; Yagiela, John A; Rutherford, Bruce; Rogy, Seigried; Navalta, Laura

2008-01-01

Phentolamine mesylate accelerates recovery from oral soft tissue anesthesia in patients who have received local anesthetic injections containing a vasoconstrictor. The proposed mechanism is that phentolamine, an alpha-adrenergic antagonist, blocks the vasoconstriction associated with the epinephrine used in dental anesthetic formulations, thus enhancing the systemic absorption of the local anesthetic from the injection site. Assessments of the pharmacokinetics of lidocaine and phentolamine, and the impact of phentolamine on the pharmacokinetics of lidocaine with epinephrine were performed to characterize this potentially valuable strategy. The blood levels of phentolamine were determined following its administration intraorally and intravenously. Additionally, the effects of phentolamine mesylate on the pharmacokinetics of intraoral injections of lidocaine with epinephrine were evaluated. Sixteen subjects were enrolled in this phase 1 trial, each receiving 4 drug treatments: 1 cartridge lidocaine/epinephrine followed after 30 minutes by 1 cartridge phentolamine (1L1P), 1 cartridge phentolamine administered intravenously (1Piv), 4 cartridges lidocaine/epinephrine followed after 30 minutes by 2 cartridges phentolamine (4L2P), and 4 cartridges lidocaine/epinephrine followed by no phentolamine (4L). Pharmacokinetic parameters estimated for phentolamine, lidocaine, and epinephrine included peak plasma concentration (Cmax), time to peak plasma concentration (Tmax), area under the plasma concentration-time curve from 0 to the last time point (AUClast) or from time 0 to infinity (AUCinf), elimination half-life (t1/2), clearance (CL), and volume of distribution (Vd). The phentolamine Tmax occurred earlier following the intravenous administration of 1Piv (7 minutes than following its submucosal administration in treatment 1L1P (15 minutes) or 4L2P (11 minutes). The phentolamine t1/2, CL, and Vd values were similar for 1L1P, 1Piv, and 4L2P. The Tmax for lidocaine occurred later and the Cmax for lidocaine was slightly higher when comparing the 4L2P treatment and the 4L treatment. The phentolamine-induced delay of the lidocaine Tmax likely represents phentolamine's ability to accelerate the systemic absorption of lidocaine from oral tissues into the systemic circulation. PMID:18547152

Human Microdosing with Carcinogenic Polycyclic Aromatic Hydrocarbons: In Vivo Pharmacokinetics of Dibenzo[ def,p ]chrysene and Metabolites by UPLC Accelerator Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madeen, Erin P.; Ognibene, Ted J.; Corley, Richard A.

Metabolism is a key health risk factor following exposures to pro-carcinogenic polycyclic aromatic hydrocarbons (PAHs) such as dibenzo[def,p]chrysene (DBC), an IARC classified 2A probable human carcinogen. Human exposure to PAHs occurs primarily from the diet in non-smokers. However, little data is available on the metabolism and pharmacokinetics in humans of high molecular weight PAHs (≥4 aromatic rings), including DBC. We previously determined the pharmacokinetics of DBC in human volunteers orally administered a micro-dose (29 ng; 5 nCi) of [14C]-DBC by accelerator mass spectrometry (AMS) analysis of total [14C] in plasma and urine. In the current study, we utilized a novelmore » “moving wire” interface between ultra-performance liquid chromatography (UPLC) and AMS to detect and quantify parent DBC and its major metabolites. The major [14C] product identified in plasma was unmetabolized [14C]-DBC itself, (Cmax= 18.5 ± 15.9 fg/mL, Tmax= 2.1 ± 1.0 h), whereas the major metabolite was identified as [14C]-(+/-)-DBC-11,12-diol (Cmax= 2.5 ± 1.3 fg/mL, Tmax= 1.8 h). Several minor species of [14C]-DBC metabolites were also detected for which no reference standards were available. Free and conjugated metabolites were detected in urine with [14C]-(+/-)-DBC-11,12,13,14-tetraol isomers identified as the major metabolites, 56.3% of which were conjugated (Cmax= 35.8 ± 23.0 pg/pool, Tmax= 6-12 h pool). [14C]-DBC-11,12-diol, of which 97.5% was conjugated, was also identified in urine (Cmax= 29.4 ± 11.6 pg/pool, Tmax= 6-12 h pool). Parent [14C]-DBC was not detected in urine. This is the first dataset to assess metabolite profiles and associated pharmacokinetics of a carcinogenic PAH in human volunteers at an environmentally relevant dose, providing the data necessary for translation of high dose animal models to humans for translation of environmental health risk assessment.« less

Pharmacokinetic Profile of Oral Cannabis in Humans: Blood and Oral Fluid Disposition and Relation to Pharmacodynamic Outcomes

PubMed Central

Vandrey, Ryan; Herrmann, Evan S.; Mitchell, John M.; Bigelow, George E.; Flegel, Ronald; LoDico, Charles; Cone, Edward J.

2017-01-01

Abstract Most research on cannabis pharmacokinetics has evaluated inhaled cannabis, but oral (“edible”) preparations comprise an increasing segment of the cannabis market. To assess oral cannabis pharmacokinetics and pharmacodynamics, healthy adults (N = 6 per dose) were administered cannabis brownies containing 10, 25 or 50 mg 9-tetrahydrocannabinol (THC). Whole blood and oral fluid specimens were obtained at baseline and then for 9 days post-exposure; 6 days in a residential research setting and 3 days as outpatients. Measures of subjective, cardiovascular and performance effects were obtained at baseline and for 8 h post-ingestion. The mean Cmax for THC in whole blood was 1, 3.5 and 3.3 ng/mL for the 10, 25 and 50 mg THC doses, respectively. The mean maximum concentration (Cmax) and mean time to maximum concentration (Tmax) of 11-OH-THC in whole blood were similar to THC. Cmax blood concentrations of THCCOOH were generally higher than THC and had longer Tmax values. The mean Tmax for THC in oral fluid occurred immediately following oral dose administration, and appear to reflect local topical residue rather than systemic bioavailbility. Mean Cmax oral fluid concentrations of THCCOOH were lower than THC, erratic over time and mean Tmax occurred at longer times than THC. The window of THC detection ranged from 0 to 22 h for whole blood (limit of quantitation (LOQ) = 0.5 ng/mL) and 1.9 to 22 h for oral fluid (LOQ = 1.0 ng/mL). Subjective drug and cognitive performance effects were generally dose dependent, peaked at 1.5–3 h post-administration, and lasted 6–8 h. Whole blood cannabinoid concentrations were significantly correlated with subjective drug effects. Correlations between blood cannabinoids and cognitive performance measures, and between oral fluid and all pharmacodynamic outcomes were either non-significant or not orderly by dose. Quantitative levels of cannabinoids in whole blood and oral fluid were low compared with levels observed following inhalation of cannabis. The route of administration is important for interpretation of cannabinoid toxicology. PMID:28158482

Human Micro-Dosing with Carcinogenic Polycyclic Aromatic Hydrocarbons: In Vivo Pharmacokinetics of Dibenzo[def,p]chrysene and Metabolites by UPLC Accelerator Mass Spectrometry

PubMed Central

Madeen, Erin P.; Ognibene, Ted J.; Corley, Richard A.; McQuistan, Tammie J.; Baird, William M.; Bench, Graham; Turteltaub, Ken W.; Williams, David E.

2017-01-01

Metabolism is a key health risk factor for exposures to pro-carcinogenic polycyclic aromatic hydrocarbons (PAHs) such as dibenzo[def,p]chrysene (DBC), an IARC classified 2A probable human carcinogen. Human exposure to PAHs occurs primarily from the diet in non-smokers. However, little data is available on the metabolism and pharmacokinetics in humans of high molecular weight PAHs (≥4 aromatic rings), including DBC. We previously determined the pharmacokinetics of DBC in human volunteers orally administered a micro-dose (29 ng; 5 nCi) of [14C]-DBC by accelerator mass spectrometry (AMS) analysis of total [14C] in plasma and urine. In the current study, we utilized a novel “moving wire” interface between ultra-performance liquid chromatography (UPLC) and the AMS to detect and quantify parent DBC and its major metabolites. The major [14C] product identified in plasma was unmetabolized [14C]-DBC itself, (Cmax= 18.5 ± 15.9 fg/mL, Tmax= 2.1 ± 1.0 h), whereas the major metabolite was identified as [14C]-(+/−)-DBC-11,12-diol (Cmax= 2.5 ± 1.3 fg/mL, Tmax= 1.8 h). Several minor species of [14C]-DBC metabolites were also detected for which no reference standards were available. Deconjugated and conjugated metabolites were detected in urine with [14C]-(+/−)-DBC-tetraol identified as the major metabolite, 88.7% of which was detected upon enzymatic deconjugation (Cmax= 35.8 ± 23.0 pg/pool, Tmax= 6–12 h pool). [14C]-DBC-11,12-diol, of which 94.4% was conjugated and identified in urine (Cmax= 29.4 ± 11.6 pg/pool, Tmax= 6–12 h pool). Parent [14C]-DBC was not detected in the urine. This is the first dataset to assess metabolite profiles and associated pharmacokinetics of a carcinogenic PAH in human volunteers at an environmentally relevant dose, providing the data necessary for translation of high dose laboratory animal models to human translation for environmental health risk assessment. PMID:27494294

Pharmacokinetics of quercetin absorption from apples and onions in healthy humans.

PubMed

Lee, Jihyun; Mitchell, Alyson E

2012-04-18

A high-throughput method for the extraction and analysis of quercetin in human plasma using 96-well SPE and LC-(ESI)MS/MS (7 min/run) is described. Quercetin exists as a range of glycosides in foods. The dominant types of quercetin glycosides vary depending on genetics (i.e., species and cultivar). Dietary sources include onions and apples (i.e., the peel). Herein the quercetin glycoside composition was determined in a composite standard of dried apple peel and in onion powder. The predominant forms of quercetin in apple peel include quercetin O-arabinoside, 3-O-galactoside, 3-O-glucoside, and 3-O-rhamnoside. In the onion powder, quercetin occurred as the quercetin 3,4'-O-glucoside and 4'-O-glucoside. Pharmacokinetics relating to absorption (C(max), t(max), and AUC(0-24 h)) and elimination (k(el) and t(1/2)) were compared after the consumption of apple peel powder (AP), onion powder (OP), or a mixture of the apple peel and onion powder enriched applesauce (MP) by healthy volunteers (eight females and eight males). The enriched applesauce delivered ∼100 mg of quercetin aglycone equivalents. Consumption of the OP resulted in C(max) = 273.2 ± 93.7 ng/mL, t(max) = 2.0 ± 1.7 h, and t(1/2) = 14.8 ± 4.8 h, whereas the AP resulted in C(max) = 63.8 ± 22.4 ng/mL, t(max) = 2.9 ± 2.0 h, and t(1/2) = 65.4 ± 80.0 h. The MP resulted in an intermediate response with C(max) = 136.5 ± 45.8 ng/mL, t(max) = 2.4 ± 1.5 h, and t(1/2) = 18.7 ± 6.8 h. Consumption of the OP led to faster absorption, higher concentration, and greater bioavailability as compared to the AP. No significant gender-related differences were observed in the absorption of quercetin, whereas significant gender-related differences in the elimination half-time (t(1/2)) were observed.

Spatio-temporal Trends of Climate Variability in North Carolina

NASA Astrophysics Data System (ADS)

Sayemuzzaman, Mohammad

Climatic trends in spatial and temporal variability of maximum temperature (Tmax), minimum temperature (Tmin), mean temperature (Tmean) and precipitation were evaluated for 249 ground-based stations in North Carolina for 1950-2009. The Mann-Kendall (MK), the Theil-Sen Approach (TSA) and the Sequential Mann-Kendall (SQMK) tests were applied to quantify the significance of trend, magnitude of trend and the trend shift, respectively. The lag-1 serial correlation and double mass curve techniques were used to address the data independency and homogeneity. The pre-whitening technique was used to eliminate the effect of auto correlation of the data series. The difference between minimum and maximum temperatures, and so the diurnal temperature range (DTR), at some stations was found to be decreasing on both an annual and a seasonal basis, with an overall increasing trend in the mean temperature. For precipitation, a statewide increasing trend in fall (highest in November) and decreasing trend in winter (highest in February) were detected. No pronounced increasing/decreasing trends were detected in annual, spring, and summer precipitation time series. Trend analysis on a spatial scale (for three physiographic regions: mountain, piedmont and coastal) revealed mixed results. Coastal zone exhibited increasing mean temperature (warming) trend as compared to other locations whereas mountain zone showed decreasing trend (cooling). Three main moisture components (precipitation, total cloud cover, and soil moisture) and the two major atmospheric circulation modes (North Atlantic Oscillation and Southern Oscillation) were used for correlative analysis purposes with the temperature (specifically with DTR) and precipitation trends. It appears that the moisture components are associated with DTR more than the circulation modes in North Carolina.

Structure and characteristics of acid and pepsin-solubilized collagens from the skin of cobia (Rachycentron canadum).

PubMed

Zeng, Shaokui; Yin, Juanjuan; Yang, Shuqi; Zhang, Chaohua; Yang, Ping; Wu, Wenlong

2012-12-01

Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the skin of cobia (Rachycentron canadum). The yields of ASC and PSC were 35.5% and 12.3%, respectively. Based on the protein patterns and carboxymethyl-cellulose chromatography, ASC and PSC were composed of α1α2α3 heterotrimers and were characterised as type I collagen with no disulfide bond. Their amounts of imino acids were 203 and 191 residues per 1000 residues, respectively. LC-MS/MS analysis demonstrated the high sequences similarities of ASC and PSC. Fourier transform infrared spectroscopy spectra showed that the amide I, II and III peaks of PSC were obtained at a lower wave number compared with ASC. The thermal denaturation temperatures of ASC and PSC, as measured by viscometry, were 34.62 and 33.97°C, respectively. The transition temperatures (T(max)) were 38.17 and 36.03°C, respectively, as determined by differential scanning calorimetry (DSC). Both collagens were soluble at acidic pH and below 2% (w/v) NaCl concentration. Copyright © 2012 Elsevier Ltd. All rights reserved.

Thermal modeling in Ceuta, Maracaibo Basin, Venezuela

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marcano, F.; Padron, S.

1993-02-01

Hydrocarbon generation from Upper Cretaceous source rocks (Fm.La Luna) in Ceuta, center-eastern Maracaibo lake area in Venezuela, is modeled here, using a kinetic method and the conventional Time-Temperature Index (TTI) procedure. Geological evolution, burial and erosional history is based on available interpretation of 3D seismic and well data. Fragmentary present-day subsurface temperature data comes from corrected measurements in a few wells. Paleogradient/heat paleoflux was estimated during the thermal modeling on wells, by calculating vitrinite reflectances (Ro) or Tmax values and then comparing them with measured ones. However, thermal-indicator data does not always appear to be consistent and some data hadmore » to be rejected. Paleogradient evolution in the Cretaceous is controlled by the development of a isolated thermal compartment related to overpressures in a thick shaly sequence in the Upper Cretaceous. A geological section was studied in detail to illustrate possible migration paths to known fields and undrilled traps. Results show a good fit between the thermal evolution of the source rock and the maturity of the crude produced in the area.« less

The pharmacokinetics of mianserin suppositories for rectal administration in dogs and healthy volunteers: a pilot study.

PubMed

Nawata, Shuichi; Kohyama, Noriko; Uchida, Naoki; Numazawa, Satoshi; Ohbayashi, Masayuki; Kobayashi, Yasuna; Iwata, Masanori; Nakajima, Takanori; Saito, Hiroshi; Izuka, Akira; Yamamoto, Toshinori

2016-01-01

We formulated mianserin suppositories for the treatment of delirium and evaluated their pharmacokinetics by measuring plasma drug concentrations in dogs and healthy human volunteers. Mianserin suppositories were prepared by a melting technique using Tetramide® tablets and Witepsol H-15 as the suppository base. Pharmacokinetics of this 30-mg mianserin preparation were evaluated in three beagle dogs and three healthy adult males, in line with ethics committee approval. Plasma mianserin levels were determined using gas chromatography-mass spectrometry. In dogs, the maximum plasma mianserin concentration (Cmax) was 1.3 ± 0.4 ng/mL, the time to Cmax (tmax) was 5.5 ± 4.3 h, and the area under the plasma concentration-time curve from 0 to 24 h (AUC0-24) was 18.9 ± 1.9 h・ng/mL. In humans, the Cmax was 14.6 ± 6.3 ng/mL, the tmax was 8 h, and the AUC0-24 was 266 ± 103 h・ng/mL. The current study characterized the pharmacokinetics of mianserin suppositories in dogs and humans. As compared to oral administration, the suppositories produced a lower Cmax and a delayed tmax, although AUC0-24 values were comparable. It will be necessary to identify an appropriate dose that produces an adequate plasma mianserin concentration for effective and safe clinical use. UMIN000013853.

Effects of tibial and humerus intraosseous administration of epinephrine in a cardiac arrest swine model.

PubMed

Beaumont, Ltc Denise; Baragchizadeh, Asal; Johnson, Charles; Johnson, Don

2016-01-01

Compare maximum concentration (Cmax), time to maximum concentration (Tmax), mean serum concentration of epinephrine, return of spontaneous circulation (ROSC), time to ROSC, and odds of survival relative to epinephrine administration by humerus intraosseous (HIO), tibial intraosseous (TIO), and intravenous (IV) routes in a swine cardiac arrest model. Prospective, between subjects, randomized experimental design. TriService Research Facility. Yorkshire-cross swine (n = 28). Swine were anesthetized and placed into cardiac arrest. After 2 minutes, cardiopulmonary resuscitation was initiated. After an additional 2 minutes, a dose of 1 mg of epinephrine was administered by HIO, TIO, or the IV routes. Blood samples were collected over 4 minutes and analyzed by high-performance liquid chromatography tandem mass spectrometry. ROSC, time to ROSC, Cmax, Tmax, mean concentrations over time, and odds ratio. There was no significant difference in rate of the ROSC among the TIO, HIO, and IV groups (p > 0.05). There were significant differences in Cmax: the HIO group was significantly higher than the TIO group (p = 0.007), but no significant difference between the IV and HIO (p = 0.33) or the IV and TIO group (p = 0.060). The Tmax was significantly shorter for both the IV and HIO versus the TIO group (p < 0.05), but no difference between IV and HIO (p = 0.328). The odds of survival were higher in the HIO group compared to all other groups. The TIO and HIO provide rapid and reliable access to administer life-saving medications during cardiac arrest.

Bioavailability of fluoride in drinking water: a human experimental study.

PubMed

Maguire, A; Zohouri, F V; Mathers, J C; Steen, I N; Hindmarch, P N; Moynihan, P J

2005-11-01

It has been suggested that systemic fluoride absorption from drinking water may be influenced by the type of fluoride compound in the water and by water hardness. Using a human double-blind cross-over trial, we conducted this study to measure c(max), T(max), and Area Under the Curve (AUC) for plasma F concentration against time, following the ingestion of naturally fluoridated hard and soft waters, artificially fluoridated hard and soft waters, and a reference water. Mean AUC over 0 to 8 hours was 1330, 1440, 1679, 1566, and 1328 ng F.min.mL(-1) for naturally fluoridated soft, naturally fluoridated hard, artificially fluoridated soft, artificially fluoridated hard, and reference waters, respectively, with no statistically significant differences among waters for AUC, c(max), or T(max). Any differences in fluoride bioavailability between drinking waters in which fluoride is present naturally or added artificially, or the waters are hard or soft, were small compared with large within- and between-subject variations in F absorption. Abbreviations used: F, fluoride; AUC, Area under the Curve for plasma F concentration against time; AUC(0-3), Area under the Curve for plasma F concentration against time for 0 to 3 hours following water ingestion; AUC(0-8), Area under the Curve for plasma F concentration against time for 0 to 8 hours following water ingestion; c(max), maximum plasma F concentration corrected for baseline plasma F and dose (i.e., F concentration of individual waters); T(max), time of c(max).

Intranasal Pharmacokinetics of Morphine ARER, a Novel Abuse-Deterrent Formulation: Results from a Randomized, Double-Blind, Four-Way Crossover Study in Nondependent, Opioid-Experienced Subjects

PubMed Central

Pantaleon, Carmela; Iverson, Matthew; Smith, Michael D.; Kinzler, Eric R.; Aigner, Stefan

2018-01-01

Objective To investigate the pharmacokinetics (PK) of Morphine ARER, an extended-release (ER), abuse-deterrent formulation of morphine sulfate after oral and intranasal administration. Methods This randomized, double-blind, double-dummy, placebo-controlled, four-way crossover study assessed the PK of morphine and its active metabolite, M6G, from crushed intranasal Morphine ARER and intact oral Morphine ARER compared with crushed intranasal ER morphine following administration to nondependent, recreational opioid users. The correlation between morphine PK and the pharmacodynamic parameter of drug liking, a measure of abuse potential, was also evaluated. Results Mean maximum observed plasma concentration (Cmax) for morphine was lower with crushed intranasal Morphine ARER (26.2 ng/mL) and intact oral Morphine ARER (18.6 ng/mL), compared with crushed intranasal ER morphine (49.5 ng/mL). The time to Cmax (Tmax) was the same for intact oral and crushed intranasal Morphine ARER (1.6 hours) and longer for crushed intranasal morphine ER (1.1 hours). Higher mean maximum morphine Cmax, Tmax, and abuse quotient (Cmax/Tmax) were positively correlated with maximum effect for drug liking (R2 ≥ 0.9795). Conclusion These data suggest that Morphine ARER maintains its ER profile despite physical manipulation and intranasal administration, which may be predictive of a lower intranasal abuse potential compared with ER morphine.

Comparative bioequivalence study of rifampicin and isoniazid combinations in healthy volunteers.

PubMed

Padgaonkar, K A; Revankar, S N; Bhatt, A D; Vaz, J A; Desai, N D; D'Sa, S; Shah, V; Gandewar, K

1999-07-01

To assess the bioavailability of rifampicin (RMP) in three brands of combination formulations of anti-tuberculosis drugs. A three-way double-blind, cross-over bioavailability study of RMP and isoniazid (INH), consisting of a comparison of a two-drug combination of tablets of RMP and INH each separately (reference brand R) and a tablet of RMP + INH (brand N), and a capsule of RMP + INH (brand L) was carried out in 12 healthy male volunteers. Coded plasma samples were analysed for levels of RMP as well as INH and acetylisoniazid (ACINH) by two high performance liquid chromatography (HPLC) methods. The mean values of RMP in brand N (Cmax 6.49+/-0.52 microg/mL, Tmax 2.33+/-0.18 h, AUC(0-24h) 39.83+/-3.44 microg/mL.h) were comparable with those obtained with brand R (Cmax 5.22+/-0.59 microg/mL, Tmax 2.50+/-0.12 h, AUC(0-24h) 33.33+/-3.47 microg/mL.h). The mean values of RMP in brand L (Cmax 3.05+/-0.52 microg/ mL, Tmax 3.79+/-0.57 h and AUC(0-24h) 21.78+/-3.67 microg/ mL.h) were significantly different from those in brand R. Nevertheless, all of the pharmacokinetic parameters obtained for INH and ACINH in all three brands were comparable. Using brand R as a comparison, brand N was bioequivalent and brand L was not bioequivalent.

Tangential Flow Ultrafiltration Allows Purification and Concentration of Lauric Acid-/Albumin-Coated Particles for Improved Magnetic Treatment.

PubMed

Zaloga, Jan; Stapf, Marcus; Nowak, Johannes; Pöttler, Marina; Friedrich, Ralf P; Tietze, Rainer; Lyer, Stefan; Lee, Geoffrey; Odenbach, Stefan; Hilger, Ingrid; Alexiou, Christoph

2015-08-14

Superparamagnetic iron oxide nanoparticles (SPIONs) are frequently used for drug targeting, hyperthermia and other biomedical purposes. Recently, we have reported the synthesis of lauric acid-/albumin-coated iron oxide nanoparticles SEON(LA-BSA), which were synthesized using excess albumin. For optimization of magnetic treatment applications, SPION suspensions need to be purified of excess surfactant and concentrated. Conventional methods for the purification and concentration of such ferrofluids often involve high shear stress and low purification rates for macromolecules, like albumin. In this work, removal of albumin by low shear stress tangential ultrafiltration and its influence on SEON(LA-BSA) particles was studied. Hydrodynamic size, surface properties and, consequently, colloidal stability of the nanoparticles remained unchanged by filtration or concentration up to four-fold (v/v). Thereby, the saturation magnetization of the suspension can be increased from 446.5 A/m up to 1667.9 A/m. In vitro analysis revealed that cellular uptake of SEON(LA-BSA) changed only marginally. The specific absorption rate (SAR) was not greatly affected by concentration. In contrast, the maximum temperature Tmax in magnetic hyperthermia is greatly enhanced from 44.4 °C up to 64.9 °C by the concentration of the particles up to 16.9 mg/mL total iron. Taken together, tangential ultrafiltration is feasible for purifying and concentrating complex hybrid coated SPION suspensions without negatively influencing specific particle characteristics. This enhances their potential for magnetic treatment.

Global variation of carbon use efficiency in terrestrial ecosystems

NASA Astrophysics Data System (ADS)

Tang, Xiaolu; Carvalhais, Nuno; Moura, Catarina; Reichstein, Markus

2017-04-01

Carbon use efficiency (CUE), defined as the ratio between net primary production (NPP) and gross primary production (GPP), is an emergent property of vegetation that describes its effectiveness in storing carbon (C) and is of significance for understanding C biosphere-atmosphere exchange dynamics. A constant CUE value of 0.5 has been widely used in terrestrial C-cycle models, such as the Carnegie-Ames-Stanford-Approach model, or the Marine Biological Laboratory/Soil Plant-Atmosphere Canopy Model, for regional or global modeling purposes. However, increasing evidence argues that CUE is not constant, but varies with ecosystem types, site fertility, climate, site management and forest age. Hence, the assumption of a constant CUE of 0.5 can produce great uncertainty in estimating global carbon dynamics between terrestrial ecosystems and the atmosphere. Here, in order to analyze the global variations in CUE and understand how CUE varies with environmental variables, a global database was constructed based on published data for crops, forests, grasslands, wetlands and tundra ecosystems. In addition to CUE data, were also collected: GPP and NPP; site variables (e.g. climate zone, site management and plant function type); climate variables (e.g. temperature and precipitation); additional carbon fluxes (e.g. soil respiration, autotrophic respiration and heterotrophic respiration); and carbon pools (e.g. stem, leaf and root biomass). Different climate metrics were derived to diagnose seasonal temperature (mean annual temperature, MAT, and maximum temperature, Tmax) and water availability proxies (mean annual precipitation, MAP, and Palmer Drought Severity Index), in order to improve the local representation of environmental variables. Additionally were also included vegetation phenology dynamics as observed by different vegetation indices from the MODIS satellite. The mean CUE of all terrestrial ecosystems was 0.45, 10% lower than the previous assumed constant CUE of 0.50. CUE varied significantly between sites - from 0.13 to 0.93 - and between ecosystem types, ranging between 0.41 and 0.60, decreasing from wetlands, to tundra, to croplands, to grasslands until the lower CUE found on average for forested ecosystems. Our analysis shows that ecosystem type was the most important predictor of CUE in terrestrial ecosystems, immediately followed by Tmax; MAT and management practices. For crop, forest and wetland ecosystems CUE varied with climate zones and a strong linear negative correlation was found between CUE and MAT and MAP for grassland ecosystems. Overall, the interaction between different environmental variables showed significant effects on CUE for all ecosystem types. Our results challenge the consideration of a constant value of 0.5 for modeling global purposes, and argue for a deeper understanding of environmental controls on CUE for different ecosystem types.

Modeling of soil nitrification responses to temperature reveals thermodynamic differences between ammonia-oxidizing activity of archaea and bacteria

PubMed Central

Taylor, Anne E; Giguere, Andrew T; Zoebelein, Conor M; Myrold, David D; Bottomley, Peter J

2017-01-01

Soil nitrification potential (NP) activities of ammonia-oxidizing archaea and bacteria (AOA and AOB, respectively) were evaluated across a temperature gradient (4–42 °C) imposed upon eight soils from four different sites in Oregon and modeled with both the macromolecular rate theory and the square root growth models to quantify the thermodynamic responses. There were significant differences in response by the dominant AOA and AOB contributing to the NPs. The optimal temperatures (Topt) for AOA- and AOB-supported NPs were significantly different (P<0.001), with AOA having Topt>12 °C greater than AOB. The change in heat capacity associated with the temperature dependence of nitrification (ΔCP‡) was correlated with Topt across the eight soils, and the ΔCP‡ of AOB activity was significantly more negative than that of AOA activity (P<0.01). Model results predicted, and confirmatory experiments showed, a significantly lower minimum temperature (Tmin) and different, albeit very similar, maximum temperature (Tmax) values for AOB than for AOA activity. The results also suggested that there may be different forms of AOA AMO that are active over different temperature ranges with different Tmin, but no evidence of multiple Tmin values within the AOB. Fundamental differences in temperature-influenced properties of nitrification driven by AOA and AOB provides support for the idea that the biochemical processes associated with NH3 oxidation in AOA and AOB differ thermodynamically from each other, and that also might account for the difficulties encountered in attempting to model the response of nitrification to temperature change in soil environments. PMID:27996979

Petrographic maturity parameters of a Devonian shale maturation series, Appalachian Basin, USA. ICCP Thermal Indices Working Group interlaboratory exercise

USGS Publications Warehouse

Araujo, Carla Viviane; Borrego, Angeles G.; Cardott, Brian; das Chagas, Renata Brenand A.; Flores, Deolinda; Goncalves, Paula; Hackley, Paul C.; Hower, James C.; Kern, Marcio Luciano; Kus, Jolanta; Mastalerz, Maria; Filho, João Graciano Mendonça; de Oliveira Mendonça, Joalice; Rego Menezes, Taissa; Newman, Jane; Suarez-Ruiz, Isabel; Sobrinho da Silva, Frederico; Viegas de Souza, Igor

2014-01-01

This paper presents results of an interlaboratory exercise on organic matter optical maturity parameters using a natural maturation series comprised by three Devonian shale samples (Huron Member, Ohio Shale) from the Appalachian Basin, USA. This work was conducted by the Thermal Indices Working Group of the International Committee for Coal and Organic Petrology (ICCP) Commission II (Geological Applications of Organic Petrology). This study aimed to compare: 1. maturation predicted by different types of petrographic parameters (vitrinite reflectance and spectral fluorescence of telalginite), 2. reproducibility of the results for these maturation parameters obtained by different laboratories, and 3. improvements in the spectral fluorescence measurement obtained using modern detection systems in comparison with the results from historical round robin exercises.Mean random vitrinite reflectance measurements presented the highest level of reproducibility (group standard deviation 0.05) for low maturity and reproducibility diminished with increasing maturation (group standard deviation 0.12).Corrected fluorescence spectra, provided by 14 participants, showed a fair to good correspondence. Standard deviation of the mean values for spectral parameters was lowest for the low maturity sample but was also fairly low for higher maturity samples.A significant improvement in the reproducibility of corrected spectral fluorescence curves was obtained in the current exercise compared to a previous investigation of Toarcian organic matter spectra in a maturation series from the Paris Basin. This improvement is demonstrated by lower values of standard deviation and is interpreted to reflect better performance of newer photo-optical measuring systems.Fluorescence parameters measured here are in good agreement with vitrinite reflectance values for the least mature shale but indicate higher maturity than shown by vitrinite reflectance for the two more mature shales. This red shift in λmax beyond 0.65% vitrinite reflectance was also observed in studies of Devonian shale in other basins, suggesting that the accepted correlation for these two petrographic thermal maturity parameters needs to be re-evaluated.A good linear correlation between λmax and Tmax for this maturation series was observed and λmax 600 nm corresponds to Tmax of 440 °C. Nevertheless if a larger set of Devonian samples is included, the correlation is polynomial with a jump in λmax ranging from 540 to 570 nm. Up to 440 °C of Tmax, the λmax, mostly, reaches up to 500 nm; beyond a Tmax of 440 °C, λmax is in the range of 580–600 nm. This relationship places the “red shift” when the onset of the oil window is reached at Tmax of 440 °C. Moreover, the correlation between HI and λmax (r2 = 0.70) shows a striking inflection and decrease in HI above a λmax of 600 nm, coincident with the approximate onset of hydrocarbon generation in these rocks.

Extreme-value statistics of fractional Brownian motion bridges.

PubMed

Delorme, Mathieu; Wiese, Kay Jörg

2016-11-01

Fractional Brownian motion is a self-affine, non-Markovian, and translationally invariant generalization of Brownian motion, depending on the Hurst exponent H. Here we investigate fractional Brownian motion where both the starting and the end point are zero, commonly referred to as bridge processes. Observables are the time t_{+} the process is positive, the maximum m it achieves, and the time t_{max} when this maximum is taken. Using a perturbative expansion around Brownian motion (H=1/2), we give the first-order result for the probability distribution of these three variables and the joint distribution of m and t_{max}. Our analytical results are tested and found to be in excellent agreement, with extensive numerical simulations for both H>1/2 and H<1/2. This precision is achieved by sampling processes with a free end point and then converting each realization to a bridge process, in generalization to what is usually done for Brownian motion.

Effects of isothermal and cyclic exposures on interface structure and mechanical properties of FPalpha-Al2O3/aluminum composites. [polycrystaline alumina fibers

NASA Technical Reports Server (NTRS)

Kim, W. M.; Koczak, M. J.; Lawley, A.

1979-01-01

The microstructural and interface stability of FPalpha-Al203/Al-Li composites are investigated as a function of isothermal exposure at 500 C or thermal cycling between 140 and 500 C with hold time at Tmax. Interfacial morphology, growth kinetics, crystal structure, and composition of interfacial reaction products are characterized. Strength is monitored in the transverse orientation, and fracture mechanics is analyzed in terms of interface reaction products. The interfacial reaction product in FP/Al is Li2O.5Al2O3. Significant fiber-matrix reaction occurs during fabrication. The number of thermal cycles rather than total time at Tmax is the determining factor in strength degradation, thermal cycling giving rise to voids at the fiber-matrix interface. Extensive interface failures occur at composite fracture stresses below about 128 MPa; above this stress level failure is attributed to ductile matrix fracture.

Activity of Highly Dispersed Co/SBA-15 Catalysts (Low Content) in Carbon Black Oxidation

NASA Astrophysics Data System (ADS)

Hassan, Nissrine El; Casale, Sandra; Aouad, Samer; Hanein, Theodor; Jabbour, Karam; Chidiac, Elvis; Khoury, Bilal el; Zakhem, Henri El; Nakat, Hanna El

Cobalt supported on mesoporous silica SBA-15 (0.75, 1.5 and 3 wt% Co) were used as catalysts for the oxidation of carbon black. Catalysts were characterized by N2 sorption, XRD, TEM and TPR. The catalytic activity in CB oxidation was measured. It has been shown that only small cobalt domains (less than 5 nm) are present on all samples. A homogeneous dispersion was obtained for all catalysts. With increasing cobalt loading, crystalline species start to appear. Using an intermediate contact between the CB and the catalyst, the best activity is that of 0.75Co/SBA-15 catalyst where the oxidation reaches the maximum (Tmax) 68 K before the non-catalyzed reaction. On the same catalyst used in tight contact mode with CB, even if Tmax didn't decrease for more than additional 12 K but the Ti decreases by 38K and thus starts 83 K before.

Effects of tibial and humerus intraosseous and intravenous vasopressin in porcine cardiac arrest model.

PubMed

Adams, Timothy S; Blouin, Dawn; Johnson, Don

2016-01-01

Compare maximum concentration (Cmax), time to maximum concentration (Tmax), mean serum concentration of vasopressin, return of spontaneous circulation (ROSC), time to ROSC, and odds of survival relative to vasopressin administration by tibial intraosseous (TIO), humerus intraosseous (HIO), and intravenous (IV) routes in a hypovolemic cardiac arrest model. Prospective, between subjects, randomized experimental design. TriService Research Facility. Yorkshire-cross swine (n = 40). Swine were anesthetized, exsanguinated to a Class III hemorrhage, and placed into cardiac arrest. After 2 minutes, cardiopulmonary resuscitation was initiated. After an additional 2 minutes, a dose of 40 units of vasopressin was administered by TIO, HIO, or the IV routes. Blood samples were collected over 4 minutes and analyzed by high-performance liquid chromatography tandem mass spectrometry. ROSC, time to ROSC, Cmax, Tmax, mean concentrations over time, and odds ratio. There was no significant difference in rate of ROSC or time to ROSC between the TIO, HIO, and IV groups (p > 0.05). The Cmax was significantly higher in the IV group compared to the TIO group (p = 0.015), but no significant difference between the TIO versus HIO or HIO versus IV groups (p > 0.05). The Tmax was significantly shorter for the HIO compared to the TIO group (p = 0.034), but no significant differences between the IV group compared to the TIO or HIO groups (p > 0.05). The odds of survival were higher in the HIO group compared to all other groups. The TIO and HIO provide rapid and reliable access to administer life-saving medications during cardiac arrest.

Preparation and in vitro and in vivo evaluation of HupA PLGA microsphere.

PubMed

Ye, Liang; Fu, Fenghua; Liu, Wanhui; Sun, Kaoxiang; Li, Youxin; He, Jie; Yu, Xin; Yu, Pengfei; Tian, Jingwei

2013-03-01

Acetylcholinesterase inhibitors (AChEIs), including Huperzine A (HupA), have been the mainstay of treatment for Alzheimer's disease (AD). However, AChEIs can cause gastrointestinal side effects, which has been related to the high Cmax and short tmax after oral administration. Clinical trials have verified that extended-release formulation with lower Cmax and prolonged tmax, such as rivastigmine patch, could perform a similar efficacy with significantly improved tolerability compared with the oral formulations. In this study, we developed an extended-release microspheres formulation of HupA (called as HAM) with poly(lactide-co-glycolide) (PLGA) as drug carrier. HAM has showed the loading rate as 1.35% (w/w) and yielded 42% with mean particle size at 72.6 μm. In vitro and in vivo pharmacokinetics studies have showed that HAM produced a relatively smooth and continuous drug concentration in 14 days. Furthermore, in vivo pharmacokinetics data have demonstrated that the Cmax was lower and the tmax was considerably later in single intramuscular administration of HAM (1,000 μg/kg) than the counterparts in single intragastric administration of HAT (75 μg/kg/d). Meanwhile, HAM has performed a continuous inhibition to brain AChE activity in normal rats and improvement of memory deficit in Aβ1-40 i.c.v. infused AD rat model for 14 days. The results have suggested that HAM has performed good extended-release properties and good prolonged pharmacological efficacy in vivo in the 2-week period, and could exert a similar efficacy with significantly lowered gastrointestinal side effects as compared with oral formulation.

Bioclimatic Thresholds, Thermal Constants and Survival of Mealybug, Phenacoccus solenopsis (Hemiptera: Pseudococcidae) in Response to Constant Temperatures on Hibiscus

PubMed Central

Sreedevi, Gudapati; Prasad, Yenumula Gerard; Prabhakar, Mathyam; Rao, Gubbala Ramachandra; Vennila, Sengottaiyan; Venkateswarlu, Bandi

2013-01-01

Temperature-driven development and survival rates of the mealybug, Phenacoccussolenopsis Tinsley (Hemiptera: Pseudococcidae) were examined at nine constant temperatures (15, 20, 25, 27, 30, 32, 35 and 40°C) on hibiscus ( Hibiscus rosa -sinensis L.). Crawlers successfully completed development to adult stage between 15 and 35°C, although their survival was affected at low temperatures. Two linear and four nonlinear models were fitted to describe developmental rates of P . solenopsis as a function of temperature, and for estimating thermal constants and bioclimatic thresholds (lower, optimum and upper temperature thresholds for development: Tmin, Topt and Tmax, respectively). Estimated thresholds between the two linear models were statistically similar. Ikemoto and Takai’s linear model permitted testing the equivalence of lower developmental thresholds for life stages of P . solenopsis reared on two hosts, hibiscus and cotton. Thermal constants required for completion of cumulative development of female and male nymphs and for the whole generation were significantly lower on hibiscus (222.2, 237.0, 308.6 degree-days, respectively) compared to cotton. Three nonlinear models performed better in describing the developmental rate for immature instars and cumulative life stages of female and male and for generation based on goodness-of-fit criteria. The simplified β type distribution function estimated Topt values closer to the observed maximum rates. Thermodynamic SSI model indicated no significant differences in the intrinsic optimum temperature estimates for different geographical populations of P . solenopsis . The estimated bioclimatic thresholds and the observed survival rates of P . solenopsis indicate the species to be high-temperature adaptive, and explained the field abundance of P . solenopsis on its host plants. PMID:24086597

Pharmacokinetic Profile of Oral Cannabis in Humans: Blood and Oral Fluid Disposition and Relation to Pharmacodynamic Outcomes.

PubMed

Vandrey, Ryan; Herrmann, Evan S; Mitchell, John M; Bigelow, George E; Flegel, Ronald; LoDico, Charles; Cone, Edward J

2017-03-01

Most research on cannabis pharmacokinetics has evaluated inhaled cannabis, but oral ("edible") preparations comprise an increasing segment of the cannabis market. To assess oral cannabis pharmacokinetics and pharmacodynamics, healthy adults (N = 6 per dose) were administered cannabis brownies containing 10, 25 or 50 mg 9-tetrahydrocannabinol (THC). Whole blood and oral fluid specimens were obtained at baseline and then for 9 days post-exposure; 6 days in a residential research setting and 3 days as outpatients. Measures of subjective, cardiovascular and performance effects were obtained at baseline and for 8 h post-ingestion. The mean Cmax for THC in whole blood was 1, 3.5 and 3.3 ng/mL for the 10, 25 and 50 mg THC doses, respectively. The mean maximum concentration (Cmax) and mean time to maximum concentration (Tmax) of 11-OH-THC in whole blood were similar to THC. Cmax blood concentrations of THCCOOH were generally higher than THC and had longer Tmax values. The mean Tmax for THC in oral fluid occurred immediately following oral dose administration, and appear to reflect local topical residue rather than systemic bioavailbility. Mean Cmax oral fluid concentrations of THCCOOH were lower than THC, erratic over time and mean Tmax occurred at longer times than THC. The window of THC detection ranged from 0 to 22 h for whole blood (limit of quantitation (LOQ) = 0.5 ng/mL) and 1.9 to 22 h for oral fluid (LOQ = 1.0 ng/mL). Subjective drug and cognitive performance effects were generally dose dependent, peaked at 1.5-3 h post-administration, and lasted 6-8 h. Whole blood cannabinoid concentrations were significantly correlated with subjective drug effects. Correlations between blood cannabinoids and cognitive performance measures, and between oral fluid and all pharmacodynamic outcomes were either non-significant or not orderly by dose. Quantitative levels of cannabinoids in whole blood and oral fluid were low compared with levels observed following inhalation of cannabis. The route of administration is important for interpretation of cannabinoid toxicology. Published by Oxford University Press 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

[Blood glucose and insulin responses to two hypocaloric enteral formulas in patients with diabetes mellitus type 2].

PubMed

de Luis, D A; Izaola, O; de la Fuente, B; Araújo, K

2013-01-01

The aim of this study is to compare the glycaemic and insulinemic response of type 2 diabetic patients after oral administration of 250 ml of two enteral formulas: a specific formula (Novasource Diabet Smartflex) against a standard isocaloric formula. The design was a cross-over study, with the diabetic patients (n = 15) receiving one of the two formulas in random order. Glycaemia and insulinemia curves were performed at 0, 10, 20, 30,60, 90,120,150 and 180 minutes. The variables studied were the area under the curve (AUC(0)-t), maximum concentration (Cmax), the time to reach maximum concentration (Tmax) and the concentrations of biochemical parameters in each study period. We studied 11 males (73.3%) and 4 females (26.7%), the mean age was 56.9 ± 10.9 years. Patients receiving Novasource Diabet showed a lower mean AUC(0)-t of glucose, mean difference - 4,753.26 mg/min/dl (95% CI: -7,256.7 to -2,249.82), also showed a mean insulinemia significantly lower AUC(0)-t, mean difference: 930.27 uU/min/ml (95% CI -1,696.34 to -164.2). The Cmax showed a significantly lower mean blood glucose levels with the specific formula, mean difference -26.89 mg/dl (95% CI -42.11 to -11.67) and insulin, mean difference: -5.39 uU/ml (95% CI: -10.37 to -1.43). The analysis shows that the mean Tmax of glucose with the specific formula are significantly lower, mean difference -19.82 min (95% CI: -32.11 to -7.33), however there was no difference in Tmax of insulin. Finally the analysis of glucose concentrations in the total study shows that the group with the specific formula has a lower mean glucose 25.77 mg / dl (95% CI 18.29 to 33.25), the same fact was detected with insulinemia 4.39 mU/ml (95% CI: 0.927 to 7.87). Diabetic patients treated diabet Novasource had significantly lower mean AUC0-t, Cmax and Tmax in blood glucose curves, also had lower mean AUC(0)-t and Cmax in insulin curves. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

Relationships between data from Rock-Eval pyrolysis and proximate, ultimate, petrographic, and physical analyses of 142 diverse U.S. coal samples

USGS Publications Warehouse

Bostick, N.H.; Daws, T.A.

1994-01-01

Basic research on coal and oil shale led to automated pyrolysis analysis of petroleum source rocks; most widely used is the Rock-Eval equipment. In order to interpret Rock-Eval analyses in relation to traditional coal data, we analyzed 142 commercial coals with diverse rank, age, maceral and sulfur contents, for most regions of the United States. We compared the Rock-Eval data with traditional industrial coal data, including volatile matter, calorific value, hydrogen and oxygen content, free swelling index, and vitrinite reflectance. We found: (1) there is a close relationship between Tmax and vitrinite reflectance in the ranges 420-590??C Tmax and 0.4-3%Romax of most coals. (2) A close relationship between Tmax and volatile matter (%VM) extends through the entire sample range, including low-rank samples with 35-70% VM, a range where %VM is not considered to be a useful rank parameter. (3) TOC of medium- and high-rank coals is seriously under-measured by Rock-Eval; TOC of low-rank coals (less than 0.8%Romax) is close to "dry basis" carbon from ultimate analysis. (4) The direct relationships between oxygen index (OI) and %O and between hydrogen index (HI) and %H are clear, though only broadly defined. However, there is virtually no band of concentrated data points on the HI versus OI pseudo-Van Krevelen diagram comparable to the "development line" on the H/C versus O/C diagram. (5) There are systematic relationships between Rock-Eval and industrial coal parameters such as calorific value and FSI, but much standardization would be needed before Rock-Eval could find a place in the coal industry. Tests with blends of coal and quartz sand and with various loads of coal alone showed that the amount of organic matter in the Rock-Eval load greatly influences results. Total load in the crucible, if largely inert, plays a small role, however. Increasing absolute or relative coal content causes under-evaluation of Rock-Eval TOC and over-rating of hydrogen. Blends of several coals yielded hydrogen and oxygen indexes related proportionally to the properties of the individual coals, but Tmax is not raised by addition of high-rank coal until over 40% is added. ?? 1994.

[Effects of PASP-KT-NAA on the grain-filling of maize in different accumulated temperature zones of Hilongjiang Province, Norheast China].

PubMed

Xu, Tian-Jun; Dong, Zhi-Qiang; Gao, Jiao; Chen, Chuan-Xiao; Jiao, Liu; Xie, Zhen-Xing

2013-02-01

Taking the two maize varieties Zhengdan 958 and Fengdan 3 grown on the three accumulated temperature zones (I, II and III) in Heilongjiang Provice as test materials, a field investigation was made in 2010 and 2011 to study the effects of PASP-KT-NAA (PKN), a compound of exogenous plant growth regulators, on the grain filling and yield of the varieties under different environmental temperatures. From zone I to III, the air temperature at the grain filling stage had a decreasing trend, with the average minimum temperature being 12.16, 11.40, and 9.56, respectively. The effective accumulated temperature at the mid-ate amt sae stage of grain filling was too low to be sufficient for grain filling, which severely affected the grain filling process. Applying N, P and K promoted the dry matter accumulation of maize grain and the grain filling rate in the three zones, delayed the peak time (Tmax) of the grain filling rate of Fengdan 3 but advanced that of Zhengdan 958, promoted the growth capacity at peak time of grain filling rate and the maximum grain filling rate of the two varieties, and shortened their active grain filling period. Applying N, P, and K increased the grain yield of the two varieties in the three zones obviously, and, as compared with those in zones I and II , the grain yields of Zhengdan 958 and Fengdan 3 in zone III were increased by 8.2% and 5.1% , and 3.4% and 0.8% , respectively. Therefore, applying N, P and K could help maize utilizing the limited accumulation temperature, improve the grain filling rate, decrease the grain water content, and ultimately, increase the maize yield.

Multiple comparisons permutation test for image based data mining in radiotherapy.

PubMed

Chen, Chun; Witte, Marnix; Heemsbergen, Wilma; van Herk, Marcel

2013-12-23

: Comparing incidental dose distributions (i.e. images) of patients with different outcomes is a straightforward way to explore dose-response hypotheses in radiotherapy. In this paper, we introduced a permutation test that compares images, such as dose distributions from radiotherapy, while tackling the multiple comparisons problem. A test statistic Tmax was proposed that summarizes the differences between the images into a single value and a permutation procedure was employed to compute the adjusted p-value. We demonstrated the method in two retrospective studies: a prostate study that relates 3D dose distributions to failure, and an esophagus study that relates 2D surface dose distributions of the esophagus to acute esophagus toxicity. As a result, we were able to identify suspicious regions that are significantly associated with failure (prostate study) or toxicity (esophagus study). Permutation testing allows direct comparison of images from different patient categories and is a useful tool for data mining in radiotherapy.

Glacial influence and stream macroinvertebrate biodiversity under climate change: Lessons from the Southern Alps.

PubMed

Lencioni, Valeria

2018-05-01

The aim of this work was to highlight the main ecological predictors driving invertebrate distribution in eight glacier-fed streams in the Southern Alps. Thirty-five sites belonging to four stream types were sampled monthly during the ablation season of one, two or three years between 1996 and 2014. Taxa from glacial (kryal and glacio-rhithral) and non-glacial (kreno-rhithral and lake outlet) sites were separated by canonical correspondence analysis (CCA) along a glacial influence gradient and a hydrological-altitudinal gradient. High glacial influence was associated mainly with low maximum water temperature (Tmax), high Glacial Index (calculated as a function of glacier area and distance from the glacier), and the abundance of Diamesa species (D. steinboecki, D. goetghebueri, D. zernyi, and D. latitarsis). Change-point analysis and Threshold Indicator Taxa Analysis confirmed the CCA results in identifying these Diamesa species as the taxa with the strongest preference for high percent glacier cover in the catchment (change point~30%) and low Tmax (change point~6°C). Temporal changes in community structure were highlighted in seven sites fed by glaciers under different retreat rates. Where the rate was faster and the remaining glacier smaller (≪1km 2 ), the most cold-stenothermal kryal inhabitant, D. steinboecki, almost disappeared or survived only as brachypterous populations, whereas other Diamesinae (Pseudokiefferiella parva), Orthocladiinae (e.g. Eukiefferiella, Orthocladius), Limoniidae, Baetidae, Nemouridae, and non-insect taxa (e.g. Oligochaeta, Hydracarina) became more abundant. Upstream migration was observed in Diamesa spp. which conquered new stream reaches left free by the retreating glacier, and euriecious taxa which colonized reaches with ameliorated environmental conditions, no longer the exclusive habitat of Diamesa spp. Co-occurrence of stochastic and deterministic assembly processes seem to drive spatio-temporal changes in these invertebrate communities. Long-term ecological studies on the adaptive biology of kryal species will be useful to predict the fate of Alpine biodiversity. Copyright © 2017 Elsevier B.V. All rights reserved.

Solid lipid nanoparticles for nose to brain delivery of haloperidol: in vitro drug release and pharmacokinetics evaluation

PubMed Central

Yasir, Mohd; Sara, Udai Vir Singh

2014-01-01

In the present study, haloperidol (HP)-loaded solid lipid nanoparticles (SLNs) were prepared to enhance the uptake of HP to brain via intranasal (i.n.) delivery. SLNs were prepared by a modified emulsification–diffusion technique and evaluated for particle size, zeta potential, drug entrapment efficiency, in vitro drug release, and stability. All parameters were found to be in an acceptable range. In vitro drug release was found to be 94.16±4.78% after 24 h and was fitted to the Higuchi model with a very high correlation coefficient (R2=0.9941). Pharmacokinetics studies were performed on albino Wistar rats and the concentration of HP in brain and blood was measured by high performance liquid chromatography. The brain/blood ratio at 0.5 h for HP-SLNs i.n., HP sol. i.n. and HP sol. i.v. was 1.61, 0.17 and 0.031, respectively, indicating direct nose-to-brain transport, bypassing the blood–brain barrier. The maximum concentration (Cmax) in brain achieved from i.n. administration of HP-SLNs (329.17±20.89 ng/mL, Tmax 2 h) was significantly higher than that achieved after i.v. (76.95±7.62 ng/mL, Tmax 1 h), and i.n. (90.13±6.28 ng/mL, Tmax 2 h) administration of HP sol. The highest drug-targeting efficiency (2362.43%) and direct transport percentage (95.77%) was found with HP-SLNs as compared to the other formulations. Higher DTE (%) and DTP (%) suggest that HP-SLNs have better brain targeting efficiency as compared to other formulations. PMID:26579417

Effects of humerus intraosseous versus intravenous amiodarone administration in a hypovolemic porcine model.

PubMed

Holloway, Cpt Monica M; Jurina, Cpt Shannan L; Orszag, Cpt Joshua D; Bragdon, Lt George R; Green, Lt Rustin D; Garcia-Blanco, Jose C; Benham, Brian E; Adams, Ltc Timothy S; Johnson, Don

2016-01-01

To compare the effects of amiodarone administration by humerus intraosseous (HIO) and intravenous (IV) routes on return of spontaneous circulation (ROSC), time to maximum concentration (Tmax), maximum plasma drug concentration (Cmax), time to ROSC, and mean concentrations over time in a hypovolemic cardiac arrest model. Prospective, between subjects, randomized experimental design. TriService Research Facility. Yorkshire-cross swine (n = 28). Swine were anesthetized and placed into cardiac arrest. After 2 minutes, cardiopulmonary resuscitation was initiated. After an additional 2 minutes, amiodarone 300 mg was administered via the HIO or the IV route. Blood samples were collected over 5 minutes. The samples were analyzed using high-performance liquid chromatography tandem mass spectrometry. ROSC, Tmax, Cmax, time to ROSC, and mean concentrations over time. There was no difference in ROSC between the HIO and IV groups; each had five achieve ROSC and two that did not (p = 1). There was no difference in Tmax (p = 0.501) or in Cmax between HIO and IV groups (p = 0.232). Means ± standard deviations in seconds were 94.3 ± 78.3 compared to 115.7 ± 87.3 in the IV versus HIO groups, respectively. The mean ± standard deviation in nanograms per milliliter for the HIO was 49,041 ± 21,107 and 74,258 ± 33,176 for the IV group. There were no significant differences between the HIO and IV groups relative to time to ROSC (p = 0.220). A repeated analysis of variance indicated that there were no significant differences between the groups relative to concentrations over time (p > 0.05). The humerus intraosseous provides rapid and reliable access to administer life-saving medications during cardiac arrest.

Sternal Route More Effective than Tibial Route for Intraosseous Amiodarone Administration in a Swine Model of Ventricular Fibrillation.

PubMed

Burgert, James M; Martinez, Andre; O'Sullivan, Mara; Blouin, Dawn; Long, Audrey; Johnson, Arthur D

2018-01-01

The pharmacokinetics of IO administered lipid soluble amiodarone during ventricular fibrillation (VF) with ongoing CPR are unknown. This study measured mean plasma concentration over 5 minutes, maximum plasma concentration (Cmax), and time to maximum concentration (Tmax) of amiodarone administered by the sternal IO (SIO), tibial IO (TIO), and IV routes in a swine model of VF with ongoing CPR. Twenty-one Yorkshire-cross swine were randomly assigned to three groups: SIO, TIO, and IV. Ventricular fibrillation was induced under general anesthesia. After 4 minutes in VF, 300 mg amiodarone was administered as indicated by group assignment. Serial blood specimens collected at 30, 60, 90, 120, 150, 180, 240, and 300 seconds were analyzed using high performance liquid chromatography with tandem mass spectrometry. The mean plasma concentration of IV amiodarone over 5 minutes was significantly higher than the TIO group at 60 seconds (P = 0.02) and 90 seconds (P = 0.017) post-injection. No significant differences in Cmax between the groups were found (P <0.05). The Tmax of amiodarone was significantly shorter in the SIO (99 secs) and IV (86 secs) groups compared to the TIO group (215 secs); P = 0.002 and P = 0.002, respectively. The SIO and IV routes of amiodarone administration were comparable. The TIO group took nearly three times longer to reach Tmax than the SIO and IV groups, likely indicating depot of lipid-soluble amiodarone in adipose-rich tibial yellow bone marrow. The SIO route was more effective than the TIO route for amiodarone delivery in a swine model of VF with ongoing CPR. Further investigations are necessary to determine if the kinetic differences found between the SIO and TIO routes in this study affect survival of VF in humans.

Nondairy creamer, but not milk, delays the appearance of coffee phenolic acid equivalents in human plasma.

PubMed

Renouf, Mathieu; Marmet, Cynthia; Guy, Philippe; Fraering, Anne-Lise; Longet, Karin; Moulin, Julie; Enslen, Marc; Barron, Denis; Cavin, Christophe; Dionisi, Fabiola; Rezzi, Serge; Kochhar, Sunil; Steiling, Heike; Williamson, Gary

2010-02-01

Chlorogenic acids (CGA) are antioxidants found in coffee. They are becoming of interest for their health-promoting effects, but bioavailability in humans is not well understood. We hypothesized that adding whole milk or sugar and nondairy creamer to instant coffee might modulate the bioavailability of coffee phenolics. Nine healthy participants were asked to randomly drink, in a crossover design, instant coffee (Coffee); instant coffee and 10% whole milk (Milk); or instant coffee, sugar, and nondairy creamer already premixed (Sugar/NDC). All 3 treatments provided the same amount of total CGA (332 mg). Blood was collected for 12 h after ingestion and plasma samples treated using a liquid-liquid extraction method that included a full enzymatic cleavage to hydrolyze all CGA and conjugates into phenolic acid equivalents. Hence, we focused our liquid chromatography-Electrospray ionization-tandem MS detection and quantification on caffeic acid (CA), ferulic acid (FA), and isoferulic acid (iFA) equivalents. Compared with a regular black instant coffee, the addition of milk did not significantly alter the area under the curve (AUC), maximum plasma concentration (C(max)), or the time needed to reach C(max) (T(max)). The C(max) of CA and iFA were significantly lower and the T(max) of FA and iFA significantly longer for the Sugar/NDC group than for the Coffee group. However, the AUC did not significantly differ. As a conclusion, adding whole milk did not alter the overall bioavailability of coffee phenolic acids, whereas sugar and nondairy creamer affected the T(max) and C(max) but not the appearance of coffee phenolics in plasma.

Safety and pharmacokinetics of oral cannabidiol when administered concomitantly with intravenous fentanyl in humans

PubMed Central

Manini, Alex F.; Yiannoulos, Georgia; Bergamaschi, Mateus M.; Hernandez, Stephanie; Olmedo, Ruben; Barnes, Allan J.; Winkel, Gary; Sinha, Rajita; Jutras-Aswad, Didier; Huestis, Marilyn A.; Hurd, Yasmin L.

2015-01-01

Objectives Cannabidiol (CBD) is hypothesized as a potential treatment for opioid addiction, with safety studies an important first step for medication development. We determined CBD safety and pharmacokinetics when administered concomitantly with a high-potency opioid in healthy subjects. Methods This double-blind, placebo-controlled cross-over study of CBD co-administered with intravenous fentanyl, was conducted at the Clinical Research Center in Mount Sinai Hospital, a tertiary care medical center in New York City. Participants were healthy volunteers aged 21–65 years with prior opioid exposure, regardless of route. Blood samples were obtained before and after 400 or 800 mg CBD pretreatment, followed by a single 0.5 (Session 1) or 1.0mcg/Kg (Session 2) intravenous fentanyl dose. The primary outcome was the Systematic Assessment for Treatment Emergent Events (SAFTEE) to assess safety and adverse effects. CBD peak plasma concentrations, time to reach peak plasma concentrations (tmax), and area under the curve (AUC) were measured. Results SAFTEE data were similar between groups without respiratory depression or cardiovascular complications during any test session. Following low dose CBD, tmax occurred at 3 and 1.5h (Sessions 1 and 2, respectively). Following high dose CBD, tmax occurred at 3 and 4h in Sessions 1 and 2, respectively. There were no significant differences in plasma CBD or cortisol (AUC p=NS) between sessions. Conclusions CBD does not exacerbate adverse effects associated with intravenous fentanyl administration. Co-administration of CBD and opioids was safe and well tolerated. These data provide the foundation for future studies examining CBD as a potential treatment for opioid abuse. PMID:25748562

Bioavailability of the Yuzpe and levonorgestrel regimens of emergency contraception: vaginal vs. oral administration.

PubMed

Kives, Sari; Hahn, Philip M; White, Emily; Stanczyk, Frank Z; Reid, Robert L

2005-03-01

Separate crossover studies compared the bioavailability of oral vs. vaginal routes of administration for the Yuzpe (n=5) and levonorgestrel regimens (n=4) of emergency contraception. Twice the standard dose of the Yuzpe regimen (200 microg of ethinyl estradiol, 1000 microg of levonorgestrel) or the levonorgestrel regimen (1500 microg of levonorgestrel) was self-administered vaginally. One week later, each subject received orally the standard dose of the assigned medication. Serial blood samples were collected over 24 h and assayed for levonorgestrel and ethinyl estradiol (for the Yuzpe regimen only). Paired t tests were used to compare oral vs. vaginal administration for maximum concentration (Cmax), time to maximum concentration (Tmax) and area under the curve over 24 h (AUC0-24). Relative bioavailability (vaginal/oral) was derived from AUC0-24. Vaginal administration of double the standard dose of the Yuzpe regimen resulted in a lower Cmax (vaginal=5.4 vs. oral=14.6 ng/mL, p=.038) and a later Tmax (5.9 vs. 2.0 h, p=.066) for levonorgestrel, compared to oral administration. Corresponding ethinyl estradiol concentrations were higher (786 vs. 391 pg/mL, p=.039) and peaked later (4.0 vs. 1.9 hr, p=.154) with vaginal administration. Relative bioavailabilities for levonorgestrel and ethinyl estradiol were 58% and 175%, respectively. Similarly, vaginal administration of the levonorgestrel regimen resulted in a lower Cmax (vaginal=5.4 vs. oral=15.2 ng/mL, p=.006) and a later Tmax (7.4 vs. 1.3 h, p=.037) for levonorgestel, compared to oral administration. The relative bioavailability was 62%. Our preliminary data suggest that vaginal administration of these emergency contraception regimens appears to require at least three times the standard oral dose to achieve equivalent systemic levonorgestrel concentrations.

A Comparison of the Regional Circulation in the Feet between Dialysis and Non-Dialysis Patients using Indocyanine Green Angiography.

PubMed

Nishizawa, M; Igari, K; Kudo, T; Toyofuku, T; Inoue, Y; Uetake, H

2017-09-01

Peripheral artery disease in dialysis cases is more prone to critical limb ischemia compared to non-dialysis cases, with a significantly high rate of major amputation of the lower limbs. Lesions are distributed on the more distal side in dialysis critical limb ischemia cases. The aim of this study was to investigate the usefulness of indocyanine green angiography to determine differences in the regional circulation in the foot between dialysis and non-dialysis patients. The subjects included 62 cases, among which 20 were dialysis patients and 42 were non-dialysis patients. We compared the indocyanine green angiography parameters for regions of interest in the dialysis and non-dialysis groups, which included the magnitude of intensity from indocyanine green onset to maximum intensity (Imax), the time from indocyanine green onset to maximum intensity (Tmax), the time elapsed from the fluorescence onset to half the maximum intensity (T1/2), and the time from maximum intensity to declining to 90% of the maximum intensity (Td90%). These indocyanine green angiography parameters were measured at region of interest 1 (the Chopart joint), region of interest 2 (the Lisfranc joint), and region of interest 3 (the distal region of the first metatarsal bone). In the comparison between the dialysis and non-dialysis groups, a significant difference was observed regarding Tmax, T1/2, and Td90%, especially in region of interest 3. In this study, we show that regional tissue perfusion is more deteriorated in dialysis patients compared with non-dialysis patients using indocyanine green angiography. Tmax, T1/2, and Td90% could be useful clinical parameters to compare ischemic severity of the lower limb between dialysis and non-dialysis patients.

Bioequivalence assessment of ambroxol tablet after a single oral dose administration to healthy male volunteers.

PubMed

Lee, Hee Joo; Joung, Sun Koung; Kim, Yoon Gyoon; Yoo, Jeong-Yeon; Han, Sang Beom

2004-01-01

A bioequivalence study of the ambroxol hydrochloride tablets was conducted. Twenty-four healthy male Korean volunteers received each medicine at the ambroxol hydrochloride dose of 30 mg in a 2 x 2 cross-over study. There was a 1-week washout period between the doses. Plasma concentrations of ambroxol were monitored by a high-performance liquid chromatography (HPLC) for over a period of 24h after the administration. AUC(t) (the area under the plasma concentration-time curve from time 0 to last sampling time, 24h) was calculated by the linear-log trapezoidal rule method. C(max) (maximum plasma drug concentration) and T(max) (time to reach C(max)) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUC(t) and C(max), and untransformed T(max). The geometric mean of AUC(t) was 495.8 ng ml(-1)h(-1) (test medication) and 468.3 ng ml(-1)h(-1) (reference medication). C(max) of 61.5 and 57.3 ng ml(-1) were achieved for the test and the reference medication, respectively. The point estimates and 90% confidence intervals for AUC(t) (parametric) and C(max) (parametric) were, in point estimate (90% confidence interval), 1.058 (0.989-1.134) and 1.073 (1.007-1.142), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. The corresponding value of T(max) was 0.229 (0.015-0.444). These results indicate that the two medications of ambroxol hydrochloride are bioequivalent and, thus, may be prescribed interchangeably.

Pharmacokinetics study of ferulic acid in rats after oral administration of γ-oryzanol under combined use of Tween 80 by LC/MS/MS.

PubMed

Pan, Y; Cai, L; He, S; Zhang, Z

2014-01-01

γ-oryzanol (OZ) is a rich source of commercially-important bioactive phytochemicals, most of them of interest in nutrition, pharmacy and cosmetics. However, the poor solubility of OZ limited the use. In the paper, ultraviolet-visible (UV-Vis) analysis was conducted to analysis the solubilization of OZ under combined use of Tween 80 in vitro. In addition, to further confirm the solubilizing effect of Tween 80, a pharmacokinetic study of ferulic acid (FA) in rats after oral administration of OZ 100 mg/kg under combined use of Tween 80 though LCMS/MS was carried out. Solubility enhancement as high as 100-fold is achieved using 1% Tween 80 in vitro. Following oral administration of OZ-Tween 80 100 mg/kg, the values of Tmax, Cmax, AUC0-∞, T1/2Ka and MRT0-∞ were 46.667 ± 39.328, 129.498 ± 27.025, 63738.28 ± 599, 14.274 ± 7.309 and 859.592 ± 108.780 respectively. The values of T1/2Ka, AUC0-∞, MRT0-t, and Tmax showed up to increase 16%, 58%, 44% and 47% while Cmax and CL/F decreased 22% and 12%, respectively. The decreased Cmax value indicated that Tween 80 can hardly enhance the absorption of FA in rats. However, T1/2Ka and Tmax values showed that the absorption of FA was extended, which resulted the increased values of AUC0-∞ and MRT0-∞. Our results reveal that Tween 80 improves solubility of OZ in vitro and could enhance the bioavailability of OZ by extending its absorption and elimination.

Absorption of phenytoin from rectal suppositories formulated with a polyethylene glycol base.

PubMed

Burstein, A H; Fisher, K M; McPherson, M L; Roby, C A

2000-05-01

To compare phenytoin pharmacokinetics following administration of an oral suspension and a rectal suppository formulated with a polyethylene glycol base. Unblinded, single-dose, randomized, crossover trial. University-affiliated pharmacokinetics and biopharmaceutics laboratory. Six healthy subjects. Subjects were given a single 200-mg dose of phenytoin as an oral suspension and a rectal suppository separated by a 1-week washout. Blood for plasma phenytoin concentrations was obtained at baseline and 0.5, 1, 2, 4, 6, 8, 10, 12, and 24 hours after administration. Plasma was analyzed by high-performance liquid chromatography (coefficient of variation < 6%) for total phenytoin concentration. Phenytoin maximum concentration (Cmax), time to Cmax (Tmax), time to first measurable concentration (Tlag), and area under the curve from time zero to time of last measurable concentration (AUClast) were estimated for oral and rectal administration by WinNonlin (v 1.1) and compared using Wilcoxon's signed rank test (p<0.05 for statistical significance). Two subjects did not have detectable plasma phenytoin concentrations after rectal administration. For the other four subjects, median rectal Cmax was significantly lower than oral Cmax (0.4 vs 1.9 microg/ml, p=0.028), median rectal Tmax did not differ from oral Tmax (11.9 vs 8.0 hrs, p=0.465), and median rectal AUClast, although highly variable, was significantly lower than oral AUClast (5.4 vs 36.2 microg x hr/ml, p=0.046). No Tlag was seen after oral administration, but with rectal administration the median Tlag was 2 hours. The estimated relative bioavailability of rectal phenytoin suppositories based on AUC0-24 was 4.7%, with individual values ranging from 0-58.3%. It appears that absorption of phenytoin from polyethylene glycol rectal suppositories in healthy subjects is highly variable and unpredictable. Thus this formulation is not recommended.

Pulmonary disposition and pharmacokinetics of minocycline in adult horses.

PubMed

Echeverria, Kate O; Lascola, Kara M; Giguère, Steeve; Foreman, Jonathan H; Austin, Scott A

2017-11-01

OBJECTIVE To determine pharmacokinetics and pulmonary disposition of minocycline in horses after IV and intragastric administration. ANIMALS 7 healthy adult horses. PROCEDURES For experiment 1 of the study, minocycline was administered IV (2.2 mg/kg) or intragastrically (4 mg/kg) to 6 horses by use of a randomized crossover design. Plasma samples were obtained before and 16 times within 36 hours after minocycline administration. Bronchoalveolar lavage (BAL) was performed 4 times within 24 hours after minocycline administration for collection of pulmonary epithelial lining fluid (PELF) and BAL cells. For experiment 2, minocycline was administered intragastrically (4 mg/kg, q 12 h, for 5 doses) to 6 horses. Plasma samples were obtained before and 20 times within 96 hours after minocycline administration. A BAL was performed 6 times within 72 hours after minocycline administration for collection of PELF samples and BAL cells. RESULTS Mean bioavailability of minocycline was 48% (range, 35% to 75%). At steady state, mean ± SD maximum concentration (Cmax) of minocycline in plasma was 2.3 ± 1.3 μg/mL, and terminal half-life was 11.8 ± 0.5 hours. Median time to Cmax (Tmax) was 1.3 hours (interquartile range [IQR], 1.0 to 1.5 hours). The Cmax and Tmax of minocycline in the PELF were 10.5 ± 12.8 μg/mL and 9.0 hours (IQR, 5.5 to 12.0 hours), respectively. The Cmax and Tmax for BAL cells were 0.24 ± 0.1 μg/mL and 6.0 hours (IQR, 0 to 6.0 hours), respectively. CONCLUSIONS AND CLINICAL RELEVANCE Minocycline was distributed into the PELF and BAL cells of adult horses.

Objective Measurement of Arterial Flow Before and After Transcatheter Arterial Chemoembolization: A Feasibility Study Using Quantitative Color-Coding Analysis.

PubMed

Lin, Yi-Yang; Lee, Rheun-Chuan; Tseng, Hsiuo-Shan; Liu, Chien-An; Guo, Wan-Yuo; Chang, Cheng-Yen

2015-12-01

To quantitatively measure the hemodynamic change of hepatic artery before and after transcatheter arterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) by quantitative color-coding analysis (QCA). This prospective study registered 64 consecutive HCC patients who underwent segmental or subsegmental TACE with epirubicin and lipiodol at level 2 or 3 of the subjective angiographic chemoembolization endpoint. QCA was used to determine the maximal density time (T(max)) of selected intravascular region of interest (ROI). Relative T(max) (rT(max)) was defined as the T(max) at the selected ROI minus the time of contrast medium spurting from the catheter tip. The rT(max) of hepatic arteries was analyzed before and after embolization. The pre- and post-treatment rT(max) of the landmarks at the treated segmental artery were 1.96 ± 0.48 and 3.14 ± 1.77 s, p < 0.001. According to the treated lobe, 30 patients were treated for the right lobe alone, and 8 patients were treated for the left lobe alone. The pre- and post-rT(max) of treated segmental artery were 2.06 ± 0.54, 3.34 ± 1.63 s, p < 0.001 and 1.89 ± 0.45, 2.68 ± 1.46 s, p = 0.12, respectively. The rT(max) of the proximal lobar hepatic arteries or proper hepatic artery had no significant change before and after TACE. The QCA is feasible to quantify embolization endpoints by comparing the rT(max) in selected hepatic arteries before and after TACE. The rT(max) of treated segmental artery was significant prolonged after optimized procedures.

Differential pharmacokinetics of diclofenac potassium for oral solution vs immediate-release tablets from a randomized trial: effect of fed and fasting conditions.

PubMed

Chen, Cuiping; Bujanover, Shay; Kareht, Stephanie; Rapoport, Alan M

2015-02-01

To compare the pharmacokinetics of, and food effect on, diclofenac potassium delivered as an oral solution vs an immediate-release tablet. Diclofenac potassium for oral solution is the only nonsteroidal anti-inflammatory drug approved as monotherapy for the acute treatment of migraine attacks with or without aura in adults 18 years of age or older. It is formulated with potassium bicarbonate as a buffering agent to raise the pH and consequently increase the aqueous solubility of diclofenac in the acidic environment of the stomach following oral administration. The dosage is 50 mg of powdered diclofenac potassium dissolved in 1 to 2 ounces (30 to 60 mL) of water prior to administration, with dosing time in relation to food intake not specified - this was the case for the pivotal efficacy and safety trials in subjects with acute migraine attacks in which the primary endpoints were achieved. For acute treatment of migraine attacks, rapid onset of pain relief is desirable and is likely related to a rapid appearance of an effective concentration of the drug in the systemic circulation. The rate at which an orally administered drug reaches the blood is affected by both its formulation and the presence of food in the stomach. The present study was designed to investigate the pharmacokinetics of 2 formulations of diclofenac potassium, an immediate-release tablet and an oral solution, and to ascertain the effect of food. This was an open-label, randomized, single-center, crossover trial in healthy volunteers. Subjects were randomized using computer-generated list to 1:1:1:1 ratio. They received a single 50-mg dose of diclofenac potassium in 4 sequences (ABCD, BADC, CDBA, and DCAB) during each of the 4 treatment periods. The 4 treatments were: A, oral solution fasting; B, tablet fasting; C, oral solution fed; and D, tablet fed. There was a ≥7-day washout period between dosing. Blood samples for pharmacokinetic analysis were taken for up to 12 hours post-dose and analyzed for diclofenac concentrations. Pharmacokinetic parameters, including peak concentration (Cmax ), time to Cmax (tmax ), area under the concentration-time curve (AUC) from time 0 to last measurable concentration (AUCt ), and extrapolation to infinity (AUC∞ ) were obtained using non-compartmental analysis. Comparative assessments for Cmax and AUC were performed between the solution and tablet under fed and fasting conditions and between fed and fasting states for both formulations. Bioequivalent exposure was defined as the geometric mean ratio and its 90% confidence interval falling within 80.0-125.0% for Cmax and AUC. Adverse events (AEs) were monitored throughout the trial. Sixty-one percent of the 36 randomized subjects were male, 91.7% were Caucasian, and the mean (standard deviation [SD]) age was 31.9 (7.6) years. Thirty-three (91.7%) subjects completed all 4 treatments. When taken under fed conditions, the oral solution resulted in an approximately 80% faster median tmax (0.17 vs 1.25 hours, P = .00015) and a 21% lower Cmax (mean ± SD, ng/mL: 506 ± 305 vs 835 ± 449, P = .00061) compared with the tablet. AUC values were similar between the 2 formulations. When taken under fasting conditions, the oral solution exhibited a 50% faster median tmax (0.25 vs 0.50 hours, P = .00035) to achieve a 77% higher Cmax (mean ± SD, ng/mL: 1620 ± 538 vs 1160 ± 452, P = .00032) compared with the tablet. AUCt and AUC∞ were similar between the 2 formulations. When taken under fed conditions, the oral solution resulted in a similar median tmax (0.17 vs 0.25 hours, P = .185) and 64% lower Cmax (mean ± SD, ng/mL: 506 ± 305 vs 1620 ± 538, P < .00001) compared with fasting conditions. In comparison, the tablets under fed conditions resulted in a statistically significantly delayed median tmax (1.25 vs 0.50, P = .00143) and ∼30% lower Cmax (mean ± SD, ng/mL: 835 ± 449 vs 1160 ± 452, P = .00377). AUC values were similar between fed and fasting conditions for both formulations. Twelve subjects (33%) experienced ≥1 treatment-emergent AE during the study. All AEs were mild and resolved without treatment; none resulted in study discontinuation. More treatment-emergent AEs were reported in subjects receiving the tablet compared with the solution formulation (20.0% vs 11.8 % in fasting and 17.1% vs 8.6% in fed conditions). Diclofenac potassium oral solution and tablet formulations produced statistically significantly different Cmax and tmax but similar AUC under fed and fasting conditions. Fed conditions produced significantly lower Cmax for both formulations and profoundly delayed tmax for the tablet, but had no effect on tmax for the solution formulation. These data provide insights into the importance of an earlier and greater exposure to diclofenac arising from the solution formulation than the tablet, which may account for the superiority in the onset and sustained pain reduction for the solution than the tablet formulation observed in the double-blind, efficacy/safety study in migraine patients conducted in Europe. © 2014 American Headache Society.

Evaluating the applicability of using daily forecasts from seasonal prediction systems (SPSs) for agriculture: a case study of Nepal's Terai with the NCEP CFSv2

NASA Astrophysics Data System (ADS)

Jha, Prakash K.; Athanasiadis, Panos; Gualdi, Silvio; Trabucco, Antonio; Mereu, Valentina; Shelia, Vakhtang; Hoogenboom, Gerrit

2018-03-01

Ensemble forecasts from dynamic seasonal prediction systems (SPSs) have the potential to improve decision-making for crop management to help cope with interannual weather variability. Because the reliability of crop yield predictions based on seasonal weather forecasts depends on the quality of the forecasts, it is essential to evaluate forecasts prior to agricultural applications. This study analyses the potential of Climate Forecast System version 2 (CFSv2) in predicting the Indian summer monsoon (ISM) for producing meteorological variables relevant to crop modeling. The focus area was Nepal's Terai region, and the local hindcasts were compared with weather station and reanalysis data. The results showed that the CFSv2 model accurately predicts monthly anomalies of daily maximum and minimum air temperature (Tmax and Tmin) as well as incoming total surface solar radiation (Srad). However, the daily climatologies of the respective CFSv2 hindcasts exhibit significant systematic biases compared to weather station data. The CFSv2 is less capable of predicting monthly precipitation anomalies and simulating the respective intra-seasonal variability over the growing season. Nevertheless, the observed daily climatologies of precipitation fall within the ensemble spread of the respective daily climatologies of CFSv2 hindcasts. These limitations in the CFSv2 seasonal forecasts, primarily in precipitation, restrict the potential application for predicting the interannual variability of crop yield associated with weather variability. Despite these limitations, ensemble averaging of the simulated yield using all CFSv2 members after applying bias correction may lead to satisfactory yield predictions.

Distribution, richness, quality, and thermal maturity of source rock units on the North Slope of Alaska

USGS Publications Warehouse

Peters, K.E.; Bird, K.J.; Keller, M.A.; Lillis, P.G.; Magoon, L.B.

2003-01-01

Four source rock units on the North Slope were identified, characterized, and mapped to better understand the origin of petroleum in the area: Hue-gamma ray zone (Hue-GRZ), pebble shale unit, Kingak Shale, and Shublik Formation. Rock-Eval pyrolysis, total organic carbon analysis, and well logs were used to map the present-day thickness, organic quantity (TOC), quality (hydrogen index, HI), and thermal maturity (Tmax) of each unit. To map these units, we screened all available geochemical data for wells in the study area and assumed that the top and bottom of the oil window occur at Tmax of ~440° and 470°C, respectively. Based on several assumptions related to carbon mass balance and regional distributions of TOC, the present-day source rock quantity and quality maps were used to determine the extent of fractional conversion of the kerogen to petroleum and to map the original organic richness prior to thermal maturation.

Endocervical ultrasound applicator for integrated hyperthermia and HDR brachytherapy in the treatment of locally advanced cervical carcinoma.

PubMed

Wootton, Jeffery H; Hsu, I-Chow Joe; Diederich, Chris J

2011-02-01

The clinical success of hyperthermia adjunct to radiotherapy depends on adequate temperature elevation in the tumor with minimal temperature rise in organs at risk. Existing technologies for thermal treatment of the cervix have limited spatial control or rapid energy falloff. The objective of this work is to develop an endocervical applicator using a linear array of multisectored tubular ultrasound transducers to provide 3-D conformal, locally targeted hyperthermia concomitant to radiotherapy in the uterine cervix. The catheter-based device is integrated within a HDR brachytherapy applicator to facilitate sequential and potentially simultaneous heat and radiation delivery. Treatment planning images from 35 patients who underwent HDR brachytherapy for locally advanced cervical cancer were inspected to assess the dimensions of radiation clinical target volumes (CTVs) and gross tumor volumes (GTVs) surrounding the cervix and the proximity of organs at risk. Biothermal simulation was used to identify applicator and catheter material parameters to adequately heat the cervix with minimal thermal dose accumulation in nontargeted structures. A family of ultrasound applicators was fabricated with two to three tubular transducers operating at 6.6-7.4 MHz that are unsectored (360 degrees), bisectored (2 x 180 degrees), or trisectored (3 x 120 degrees) for control of energy deposition in angle and along the device length in order to satisfy anatomical constraints. The device is housed in a 6 mm diameter PET catheter with cooling water flow for endocervical implantation. Devices were characterized by measuring acoustic efficiencies, rotational acoustic intensity distributions, and rotational temperature distributions in phantom. The CTV in HDR brachytherapy plans extends 20.5 +/- 5.0 mm from the endocervical tandem with the rectum and bladder typically <8 mm from the target boundary. The GTV extends 19.4 +/- 7.3 mm from the tandem. Simulations indicate that for 60 min treatments the applicator can heat to 41 degrees C and deliver > 5EM(43 degrees C) over 4-5 cm diameter with Tmax < 45 degrees C and 1 kg m(-3) s(-1) blood perfusion. The 41 degrees C contour diameter is reduced to 3-4 cm at 3 kg m(-3) s(-1) perfusion. Differential power control to transducer elements and sectors demonstrates tailoring of heating along the device length and in angle. Sector cuts are associated with a 14-47 degrees acoustic dead zone, depending on cut width, resulting in a approximately 2-4 degrees C temperature reduction within the dead zone below Tmax. Dead zones can be oriented for thermal protection of the rectum and bladder. Fabricated devices have acoustic efficiencies of 33.4%-51.8% with acoustic output that is well collimated in length, reflects the sectoring strategy, and is strongly correlated with temperature distributions. A catheter-based ultrasound applicator was developed for endocervical implantation with locally targeted, 3-D conformal thermal delivery to the uterine cervix. Feasibility of heating clinically relevant target volumes was demonstrated with power control along the device length and in angle to treat the cervix with minimal thermal dose delivery to the rectum and bladder.

Changes in ambient temperature differentially alter the thermoregulatory, cardiac and locomotor stimulant effects of 4-methylmethcathinone (mephedrone).

PubMed

Miller, M L; Creehan, K M; Angrish, D; Barlow, D J; Houseknecht, K L; Dickerson, T J; Taffe, M A

2013-01-01

The substituted cathinone compound known as mephedrone (4-methylmethcathinone; 4-MMC) has become popular with recreational users of psychomotor-stimulant compounds. Only recently have the first preclinical studies provided information about this drug in the scientific literature; nevertheless, media reports have led to drug control actions in the UK and across several US states. Rodent studies indicate that 4-MMC exhibits neuropharmacological similarity to 3,4-methylenedioxymethamphetamine (MDMA) and prompt investigation of the thermoregulatory, cardiac and locomotor effects of 4-MMC. This study focuses on the role of ambient temperature, which has been shown to shift the effects of MDMA from hyperthermic to hypothermic. Male Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1.0-5.6 mg/kg) using an implantable radiotelemetry system under conditions of low (20 °C) and high (30 °C) ambient temperature. A pharmacokinetic study found a T(max) of 0.25 h and a C(max) of 1206 ng/ml after 5.6 mg/kg 4-MMC. A dose-dependent reduction of body temperature was produced by 4-MMC at 20 °C but there was no temperature change at 30 °C. Increased locomotor activity was observed after 4-MMC administration under both ambient temperatures, however, significantly more activity was observed at 30 °C. Heart rate was slowed by 1.0 and 5.6 mg/kg 4-MMC at 20°C, and was slower in the 30 °C vs. 20 °C condition across all treatments. These results show that the cathinone analog 4-MMC exhibits in vivo thermoregulatory properties that are distinct from those produced by MDMA. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

End-growth/evaporation living polymerization kinetics revisited

NASA Astrophysics Data System (ADS)

Semenov, A. N.; Nyrkova, I. A.

2011-03-01

End-growth/evaporation kinetics in living polymer systems with "association-ready" free unimers (no initiator) is considered theoretically. The study is focused on the systems with long chains (typical aggregation number N ≫ 1) at long times. A closed system of continuous equations is derived and is applied to study the kinetics of the chain length distribution (CLD) following a jump of a parameter (T-jump) inducing a change of the equilibrium mean chain length from N0 to N. The continuous approach is asymptotically exact for t ≫ t1, where t1 is the dimer dissociation time. It yields a number of essentially new analytical results concerning the CLD kinetics in some representative regimes. In particular, we obtained the asymptotically exact CLD response (for N ≫ 1) to a weak T-jump (ɛ = N0/N - 1 ≪ 1). For arbitrary T-jumps we found that the longest relaxation time tmax = 1/γ is always quadratic in N (γ is the relaxation rate of the slowest normal mode). More precisely tmax ∝4N2 for N0 < 2N and tmax ∝NN0/(1 - N/N0) for N0 > 2N. The mean chain length Nn is shown to change significantly during the intermediate slow relaxation stage t1 ≪ t ≪ tmax . We predict that N_n(t)-N_n(0)∝ √{t} in the intermediate regime for weak (or moderate) T-jumps. For a deep T-quench inducing strong increase of the equilibrium Nn (N ≫ N0 ≫ 1), the mean chain length follows a similar law, N_n(t)∝ √{t}, while an opposite T-jump (inducing chain shortening, N0 ≫ N ≫ 1) leads to a power-law decrease of Nn: Nn(t)∝t-1/3. It is also shown that a living polymer system gets strongly polydisperse in the latter regime, the maximum polydispersity index r = Nw/Nn being r* ≈ 0.77N0/N ≫ 1. The concentration of free unimers relaxes mainly during the fast process with the characteristic time tf ˜ t1N0/N2. A nonexponential CLD dominated by short chains develops as a result of the fast stage in the case of N0 = 1 and N ≫ 1. The obtained analytical results are supported, in part, by comparison with numerical results found both previously and in the present paper.

Recurring Slope Lineae (RSL) and Chloride Hydrates within Mars Subsurface

NASA Astrophysics Data System (ADS)

Lu, Y.; Wang, A.

2012-12-01

RSL is an important phenomenon revealed by HiRISE-MRO observations on Mars (McEwen et al., 2011). The RSL form and grow on some equator-facing slopes during warm seasons on Mars when temperature (T in afternoon) is in the range of ~250-300K. We hypothesize that chloride hydrates may exist in some areas within the subsurface of southern hemisphere on Mars, and the deliquescence of these chloride hydrates at elevated temperature may have produced large quantity of brine that caused the RSL observed by HiRISE team. This hypothesis is based on three lines of reasoning: (1) chlorine (Cl) is found to be broadly distributed on Mars (GRS-ODY) and has been detected in the chemistry of every surface samples during all Mars surface exploration missions (Vikings, Pathfinder, Spirit, Opportunity, and Phoenix). In addition, the existence of chlorides in martian southern hemisphere was suggested by a set of THEMIS-ODY data analyses (Osterloo et al., 2008, 2010). In terrestrial saline playas, large amounts of chlorides invariably appears in the precipitates from salty brines (Zheng et al., 2009, Wang et al., 2009), although the precipitation sequence of chlorides on Mars might be different from that on Earth (Tosca et al., 2008, McLennan et al., 2012). (2) A subsurface layer when enriched with ice, or hydrous sulfates or chloride hydrates (all have high thermal inertia) and covered by a dry layer of surface soils (very low thermal inertia) will be able to maintain a lower Tmax and a much smaller delta-T that are not affected by the large temperature variations at Mars surface during diurnal and seasonal cycles (Mellon, 2004). (3) Chloride hydrates (such as MgCl2.12H2O, FeCl2.6H2O, CaCL2.6H2O, etc) would form from Cl-bearing brine at low T; they would be stable in a large T range (beyond room T in lab) and their deliquescence would occur abruptly at elevated temperatures (Baumgartner & Bakker 2009, and many others). We have started a systematic laboratory investigation on the thermodynamics and kinetics properties of chloride hydrates. The goals are to determine (1) the stability fields of Mg-, Fe2+-, Fe3+-, Ca-, Al-, Na-chloride hydrates in RH-T space, especially the phase boundaries of hydrates-deliquescence; (2) the rate of their dehydration, and especially the rate of their deliquescence as function of T, P, and PH2O; (3) the RH level that each chloride hydrate can maintain in an enclosure at T relevant to those within Mars subsurface. We will report the experimental results from (3), and will compare them with a similar set of data from hydrous sulfates (Mg, Fe, Ca, Al). The criticality of learning the property (3) is that the deliquescence of a hydrous salt at a T only occurs when RH is higher than a threshold. For example, deliquescence of ferricopiapite would happen when RH > 75% at 0°C. If the environmental RH is lower, the dehydration of hydrous salt will go through solid-solid phase transition, instead of deliquescence, such that water would be released to the atmosphere and brine would not form. It is possible that deliquescence of both hydrous sulfates and chlorides (as well as the melting of Cl-enriched brines) contributed the RSL. Our working hypothesis favors chloride hydrates because dry chloride (after releasing water) in RSL would not be visible by Vis-NIR spectroscopy, which is consistent with the mission observations.

Modeling demographic response to constant temperature in Hypera postica (Coleoptera: Curculionidae).

PubMed

Zahiri, Babak; Fathipour, Yaghoub; Khanjani, Mohammad; Moharramipour, Saeid; Zalucki, Myron P

2010-04-01

Alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), is among the most destructive pests of alfalfa, Medicago sativa L., in the world. Survivorship and fecundity schedules of H. postica were investigated to characterize the population growth potential of the weevil at six constant temperatures: 11.5, 14.0, 19.0, 24.0, 29.0, and 31.5 degrees C. Preoviposition period, oviposition period and female longevity significantly decreased with rising temperature within the temperature range tested. At the respective temperatures adult female lived an average of 294.2, 230.2, 163.6, 141.0, 84.10, and 32.9 d, with average lifetime progeny production of 470, 814, 2209, 3619, 2656, and 338 eggs per female. The net reproductive rates (R0) were 86.9, 288.0, 869.7, 1,479.7, 989.8, and 107.8 females per female, respectively. Mean daily fecundity (Mx) was modeled as a function of time by using both Enkegaard and Analytis models. Survivorship data (l(x)) of adult females were summarized and compared using the shape and scale parameters of the Weibull frequency distribution model across the temperature range tested. Life table entropy values within the range 14.0-31.5 degrees C (H < 0.5) indicates Slobodkin's type I survivorship curve; however, the value of 0.806 at 11.5 degrees C (H > 0.5) corresponds to type III. As temperature increased, the r(m) exhibited an asymmetrical dome-shaped pattern, with a maximum value of 0.114 females per female per d at 29.0 degrees C. The r(m)-temperature relation of weevils was modeled and critical temperatures (T(Min), T(Opt), and T(Max)) for intrinsic rate of increase of the weevil were computed as 8.83, 30.61, and 32.14 degrees C and 5.72, 29.94, and 32.12 degrees C by using Analytis/Allahyari and Analytis/Briere-2 models, respectively.

Temperature and relative humidity distributions in a medium-size administrative town in southwest Nigeria.

PubMed

Akinbode, O M; Eludoyin, A O; Fashae, O A

2008-04-01

This study was carried out in one of the medium-sized public administrative towns in the southwestern part of Nigeria. Its aim is to highlight the effect of spatial distribution of settlements, population, and socio-economic activities on urban air temperature and humidity in the town. Temperature and relative humidity data from 1992 to 2001 were obtained from three meteorological stations in Akure, the Administrative Capital of Ondo State, Nigeria. The stations are located within the Federal Ministry of Aviation, Akure Airport (FMA), Federal University of Technology, Akure (FUTA) and Federal School of Agriculture (SOA). Air temperature and relative humidity measurements were also obtained from 27 points, which were cited to include road junctions, markets, built up areas, etc., using sling psychrometer. The data were subsequently analysed for spatial and temporal variations using statistical packages (SPSS and Microsoft Excel) and isolines. Actual vapour pressure and dew point temperature were computed using Magnus conversion formulae. The results obtained showed that spatial variation was insignificant, in terms of the temperature and humidity variables. The annual mean temperature (Tmean) ranged between 21.9 and 30.4 degrees C while minimum (Tmin) and maximum (Tmax) temperatures varied from 13 to 26 and 21.5-39.6 degrees C, respectively. Relative humidity (RH), actual vapour pressure (Es) and dew point temperature (Td) values also varied from 39.1% to 98.2%, 19.7-20.8 gm(-3), and 17.3-17.8 degrees C, respectively. A significant relationship (p>0.6; r<0.05) between Tmin, Es and Td was observed while the daytime 'urban heat island' intensity (UHI) ranged between 0.5 and 2.5 degrees C within the study period. The study concluded that there is influence of urban canopy on the microclimate of Akure, and hypothesizes that the urban dwellers may be subjected to some levels of weather related physiological disorderliness.

[Determination of plasma concentration of quercetin, kaempferid and isorhamnetin in Hippophae rhamnoides extract by HPLC-MS/MS and pharmacokinetics in rats].

PubMed

Liu, Yu; Yang, Juan; Tuo, Yang-ling; Wei, Ting; Zeng, Yong; Wang, Ping; Meng, Xian-li

2015-10-01

To establish an HPLC-MS/MS method for the analysis of quercetin, kaempferid and isorhamnetin in rats plasma and study its pharmamacokinetics after an intragastrical administration of Hippophae rhamnoides extracts. Five healthy male Sprague-Dawley (SD) rats were given single doses of H. rhamnoides extracts (quercetin 26.35 mg x kg(-1), kaempferid 4.040 mg x kg(-1), isorhamnetin 31.37 mg x kg(-1)), and then their orbital sinus blood samples were collected at different time points. The drug plasma concentration of the three flavonoids was determined by HPLC-MS/MS method. After that, the main pharmacokinetics parameters were calculated by using Kinetica 5. 0. 11 software. The methodological test showed that the linear concentration ranges of quercetin, kaempferid and isorhamnetin were 7.500-600.0 μg x L(-1) (R2 = 0.998 5), 1.000-80.00 μg x L(-1) (R2 = 0.998 5 ) and 10.00-800.0 μg x L(-1) (R2 = 0.998 0), respectively. The inner and inter-days precisions were both less than 14.0%. The plasma samples showed a good stability and consistency with the requirement of biological sample analysis after the samples were frozen once and placed at - 20 degrees C for 15 d and room temperature for 6 h and the treated analytes were placed at -20 degrees C for 24 h. For quercetin, the pharmacokinetic parameter t(½β), AUC(0-∞), MRT(0.∞), C.(max) and T(max) were (113.3 ± 19.37) min, (12 542.14 ± 3 504.05) μg x h x L(-1), (119.6 ± 13.29) h, (164.6 ± 27.33) μg x L(-1) and (5.199 ± 0.840 3) h, respectively. For kaempferid, the pharmacokinetic parameters t(½β), AUC(0-t), MRT(0-∞), C(max) and T(max) were (79.85 ± 17.15) min, (934.51 ± 94.59) μg x h x L(-1), (81.50 ± 13.75) h, (80.15 ± 14.24) μg x L(-1) and (3.827 ± 0.902 7) h, respectively. For isorhamnetin, the pharmacokinetic parameters t1,2,, AUC(0-t), MRT(0-∞), C(max) and T(max) were (118.3 ± 20.73) min, (26 067.77 ± 4 124.60) μg x h x L(-1), (129.0 ± 16.30) h, (269.6 ± 29.32) μg x L(-1) and (6.513 ± 1.450) h, respectively. The HPLC-MS/MS analysis method established in this study was proved to be sensitive and accurate and could be applied in the pharmacokinetic study of quercetin, kaempferid and isorhamnetin in rat plasma.

Heterogeneous brittle-ductile deformation at shallow crustal levels under high thermal conditions: The case of a synkinematic contact aureole in the inner northern Apennines, southeastern Elba Island, Italy

NASA Astrophysics Data System (ADS)

Papeschi, Samuele; Musumeci, Giovanni; Mazzarini, Francesco

2017-10-01

We present an example of interaction between magmatism and tectonics at shallow crustal levels. In the Late Miocene the metamorphic units of the eastern Elba Island (northern Apennines) were intruded at very shallow crustal levels by a large pluton (> 60 km2) with the development of an hectometre-sized contact aureole defined by growth of low-pressure/high-temperature mineral assemblages (Pmax < 0.2 GPa, Tmax 650 °C). Structural data show that the contact aureole is associated with a km-sized antiform of the foliation and by several metre- to decametre-thick high-strain domains consisting of strongly foliated rocks containing synkinematic HT/LP mineral assemblages and ductile shear zones of variable thickness. These shear zones are characterized by a mylonitic foliation variably overprinted by cataclasis. Quartz microfabrics indicate that the dynamic crystallization processes progressively changed from grain boundary migration, associated with the thermal peak of contact metamorphism, to subgrain rotation and bulging recrystallization, the latter mostly associated with the cataclastic overprint. These transitions of recrystallization mechanisms in quartz are related to a progressive decrease of temperature during deformation. Deformation accompanied the development and cooling of the contact aureole, which recorded the switch from high temperature ductile to low temperature brittle conditions. The geometry of the studied deformation structures is consistent with the constraints of the regional tectonic evolution and its local interaction with the localized and transient thermal anomaly related to the coeval emplacement of igneous rocks.

Climate-based statistical regression models for crop yield forecasting of coffee in humid tropical Kerala, India

NASA Astrophysics Data System (ADS)

Jayakumar, M.; Rajavel, M.; Surendran, U.

2016-12-01

A study on the variability of coffee yield of both Coffea arabica and Coffea canephora as influenced by climate parameters (rainfall (RF), maximum temperature (Tmax), minimum temperature (Tmin), and mean relative humidity (RH)) was undertaken at Regional Coffee Research Station, Chundale, Wayanad, Kerala State, India. The result on the coffee yield data of 30 years (1980 to 2009) revealed that the yield of coffee is fluctuating with the variations in climatic parameters. Among the species, productivity was higher for C. canephora coffee than C. arabica in most of the years. Maximum yield of C. canephora (2040 kg ha-1) was recorded in 2003-2004 and there was declining trend of yield noticed in the recent years. Similarly, the maximum yield of C. arabica (1745 kg ha-1) was recorded in 1988-1989 and decreased yield was noticed in the subsequent years till 1997-1998 due to year to year variability in climate. The highest correlation coefficient was found between the yield of C. arabica coffee and maximum temperature during January (0.7) and between C. arabica coffee yield and RH during July (0.4). Yield of C. canephora coffee had highest correlation with maximum temperature, RH and rainfall during February. Statistical regression model between selected climatic parameters and yield of C. arabica and C. canephora coffee was developed to forecast the yield of coffee in Wayanad district in Kerala. The model was validated for years 2010, 2011, and 2012 with the coffee yield data obtained during the years and the prediction was found to be good.

Do Mitochondria Limit Hot Fish Hearts? Understanding the Role of Mitochondrial Function with Heat Stress in Notolabrus celidotus

PubMed Central

Iftikar, Fathima I.; Hickey, Anthony J. R.

2013-01-01

Hearts are the first organs to fail in animals exposed to heat stress. Predictions of climate change mediated increases in ocean temperatures suggest that the ectothermic heart may place tight constraints on the diversity and distribution of marine species with cardiovascular systems. For many such species, their upper temperature limits (Tmax) and respective heart failure (HF) temperature (THF) are only a few degrees from current environmental temperatures. While the ectothermic cardiovascular system acts as an “ecological thermometer,” the exact mechanism that mediates HF remains unresolved. We propose that heat-stressed cardiac mitochondria drive HF. Using a common New Zealand fish, Notolabrus celidotus, we determined the THF (27.5°C). Haemoglobin oxygen saturation appeared to be unaltered in the blood surrounding and within heat stressed hearts. Using high resolution respirometry coupled to fluorimeters, we explored temperature-mediated changes in respiration, ROS and ATP production, and overlaid these changes with THF. Even at saturating oxygen levels several mitochondrial components were compromised before THF. Importantly, the capacity to efficiently produce ATP in the heart is limited at 25°C, and this is prior to the acute THF for N. celidotus. Membrane leakiness increased significantly at 25°C, as did cytochrome c release and permeability to NADH. Maximal flux rates and the capacity for the electron transport system to uncouple were also altered at 25°C. These data indicate that mitochondrial membrane integrity is lost, depressing ATP synthesis capacity and promoting cytochrome c release, prior to THF. Mitochondria can mediate HF in heat stressed hearts in fish and play a significant role in thermal stress tolerance, and perhaps limit species distributions by contributing to HF. PMID:23724026

Do mitochondria limit hot fish hearts? Understanding the role of mitochondrial function with heat stress in Notolabrus celidotus.

PubMed

Iftikar, Fathima I; Hickey, Anthony J R

2013-01-01

Hearts are the first organs to fail in animals exposed to heat stress. Predictions of climate change mediated increases in ocean temperatures suggest that the ectothermic heart may place tight constraints on the diversity and distribution of marine species with cardiovascular systems. For many such species, their upper temperature limits (Tmax) and respective heart failure (HF) temperature (T(HF)) are only a few degrees from current environmental temperatures. While the ectothermic cardiovascular system acts as an "ecological thermometer," the exact mechanism that mediates HF remains unresolved. We propose that heat-stressed cardiac mitochondria drive HF. Using a common New Zealand fish, Notolabrus celidotus, we determined the THF (27.5°C). Haemoglobin oxygen saturation appeared to be unaltered in the blood surrounding and within heat stressed hearts. Using high resolution respirometry coupled to fluorimeters, we explored temperature-mediated changes in respiration, ROS and ATP production, and overlaid these changes with T(HF). Even at saturating oxygen levels several mitochondrial components were compromised before T(HF). Importantly, the capacity to efficiently produce ATP in the heart is limited at 25°C, and this is prior to the acute T(HF) for N. celidotus. Membrane leakiness increased significantly at 25°C, as did cytochrome c release and permeability to NADH. Maximal flux rates and the capacity for the electron transport system to uncouple were also altered at 25°C. These data indicate that mitochondrial membrane integrity is lost, depressing ATP synthesis capacity and promoting cytochrome c release, prior to T(HF). Mitochondria can mediate HF in heat stressed hearts in fish and play a significant role in thermal stress tolerance, and perhaps limit species distributions by contributing to HF.

Could thermal sensitivity of mitochondria determine species distribution in a changing climate?

PubMed

Iftikar, Fathima I; MacDonald, Julia R; Baker, Daniel W; Renshaw, Gillian M C; Hickey, Anthony J R

2014-07-01

For many aquatic species, the upper thermal limit (Tmax) and the heart failure temperature (THF) are only a few degrees away from the species' current environmental temperatures. While the mechanisms mediating temperature-induced heart failure (HF) remain unresolved, energy flow and/or oxygen supply disruptions to cardiac mitochondria may be impacted by heat stress. Recent work using a New Zealand wrasse (Notolabrus celidotus) found that ATP synthesis capacity of cardiac mitochondria collapses prior to T(HF). However, whether this effect is limited to one species from one thermal habitat remains unknown. The present study confirmed that cardiac mitochondrial dysfunction contributes to heat stress-induced HF in two additional wrasses that occupy cold temperate (Notolabrus fucicola) and tropical (Thalassoma lunare) habitats. With exposure to heat stress, T. lunare had the least scope to maintain heart function with increasing temperature. Heat-exposed fish of all species showed elevated plasma succinate, and the heart mitochondria from the cold temperate N. fucicola showed decreased phosphorylation efficiencies (depressed respiratory control ratio, RCR), cytochrome c oxidase (CCO) flux and electron transport system (ETS) flux. In situ assays conducted across a range of temperatures using naive tissues showed depressed complex II (CII) and CCO capacity, limited ETS reserve capacities and lowered efficiencies of pyruvate uptake in T. lunare and N. celidotus. Notably, alterations of mitochondrial function were detectable at saturating oxygen levels, indicating that cardiac mitochondrial insufficiency can occur prior to HF without oxygen limitation. Our data support the view that species distribution may be related to the thermal limits of mitochondrial stability and function, which will be important as oceans continue to warm. © 2014. Published by The Company of Biologists Ltd.

Productivity and some properties of egg yolk antibody (IgY) against human rotavirus compared with rabbit IgG.

PubMed

Hatta, H; Tsuda, K; Akachi, S; Kim, M; Yamamoto, T

1993-03-01

Productivity and some properties of anti-Human Rotavirus (HRV) hen egg yolk antibody (IgY) were compared with those of anti-HRV rabbit serum antibody (IgG). The hens immunized with HRV (Wa strain, serotype 1 and Mo strain, serotype 3) were found to continuously to lay eggs without any change in the egg laying rate and the yolk of the eggs laid over a year showed a high level of neutralization titer against HRV. The production of anti-HRV IgY by a hen (one year) was at least 15 times (anti-Wa) and 120 times (anti-Mo) more effective than those by an immunized rabbit in the neutralization titer of the antibodies. The stability of anti-HRV IgY at temperature above 70 degrees C and low pH 2-3 was less than that of anti-HRV rabbit IgG. The temperature corresponding to the maximum of denaturation endotherm (Tmax) of IgY was 73.9 degrees C while that of rabbit IgG was 77.0 degrees C in the analysis by differential scanning calorimetry. This discrepancy in heat and acidic pH stability found between the two antibodies as discussed with regard to their protein structures.

Physicochemical characterization and in vivo evaluation of thermosensitive diclofenac liquid suppository.

PubMed

Yong, Chul Soon; Choi, Young-Kwon; Kim, Yong-Il; Park, Byung-Joo; Quan, Qi-Zhe; Rhee, Jong-Dal; Kim, Chong-Kook; Choi, Han-Gon

2003-02-01

Liquid suppository systems composed of poloxamers and bioadhesive polymers were easy to administer to the anus and mucoadhesive to the rectal tissues without leakage after the dose. However, a liquid suppository containing diclofenac sodium could not be developed using bioadhesive polymers, since the drug was precipitated in this preparation. To develop a liquid suppository system using sodium chloride instead of bioadhesive polymers, the physicochemical properties such as gelation temperature, gel strength and bioadhesive force of various formulations composed of diclofenac sodium, poloxamers and sodium chloride were investigated. Furthermore, the pharmacokinetic study of diclofenac sodium delivered by the liquid suppository was performed. Diclofenac sodium significantly increased the gelation temperature and weakened the gel strength and bioadhesive force, while sodium chloride did the opposite. The liquid suppositories with less than 1.0% of sodium chloride, in which the drug was not precipitated, were inserted into the rectum without difficulty and leakage. Furthermore, liquid suppository gave significantly higher initial plasma concentrations and faster Tmax of diclofenac sodium than did solid suppository, indicating that drug from liquid suppository could be absorbed faster than that from solid one in rats. Our results suggested that a thermosensitive liquid suppository system with sodium chloride and poloxamers was a more physically stable, convenient and effective rectal dosage form for diclofenac sodium.

Effect of heating rate on thermal cracking characteristics and kinetics of Xinjiang oil sand bitumen by TG-FTIR

NASA Astrophysics Data System (ADS)

Hao, Junhui; Zhang, Jinhong; Qiao, Yingyun; Tian, Yuanyu

2017-08-01

This work was aimed to investigate effects of heating rate on thermal cracking behaviors, distribution of gaseous products and activation energy of the thermal cracking process of Xinjiang oil sand bitumen (OSB). The thermal cracking experiments of Xinjiang OSB were performed by using thermogravimetric analyzer (TGA) at various heating rates of 10, 20, 50, 80 and 120 K/min. The evolving characteristic of gaseous products produced from the thermal cracking process was evaluated by the Fourier transform infrared spectrometry (FTIR) connected with TG. The kinetic parameters of the thermal cracking process of Xinjiang OSB at each of heating rate were determined by the Coats-Redfern model. The result show that the temperature intervals of DE volatilization stage and main reaction stage, the ((dw/dt) max and Tmax in thermal cracking process of Xinjiang OSB all increased with the increasing heating rate. While the heating rate has not obvious effect on the coke yield of Xinjiang OSB. Furthermore, the maximum absorbance of gaseous products and corresponding temperature became larger as the heating rate increases. The activation energy of this two stage both presented increasing trend with the rising heating rate, while the increasing content of that of DE volatilization stage was weaker compared to that of main reaction stage.

Improvement of the surface hydrophilic properties of naproxen particles with addition of hydroxypropylmethyl cellulose and sodium dodecyl sulphate: In vitro and in vivo studies.

PubMed

García-Herrero, Víctor; Torrado, Carlos; García-Rodríguez, Juan José; López-Sánchez, Alicia; Torrado, Susana; Torrado-Santiago, Santiago

2017-08-30

In this study, a new surface-modified naproxen was developed to enhance brain concentration in acute migraine treatment. Fast-dissolving naproxen granules were made by mixing hydroxypropylmethylcellulose (HPMC) sodium dodecyl sulphate (SDS) and sodium croscarmellose with micronized naproxen particles. The aim of this study was to evaluate the effect of adding proportions of SDS to the HPMC film caused changes in the polymer chains of the HPMC, producing a new hydrophilic HPMC-SDS structure. These formulations with different HPMC/SDS ratios were characterised using electron microscopy (SEM), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). SDS 10% (w/w) produced a highly hydrophilic HPMC-SDS structure on the surface of the naproxen microparticles. The fast dissolution granules (SF-10%) showed a significant improvement in the dissolution rate of naproxen. Pharmacokinetic studies were conducted with mice, showing an improvement of Cmax (1.38 and 1.41-fold) and AUC0-2h (30% and 10% higher) for plasma and brain samples compared to the reference naproxen suspension. The faster Tmax ratio for SF-10% may be related to increased hydration in the gastrointestinal environment, enabling the drug to permeate the gastrointestinal hydration layer more easily due to the presence of the hydrophilic HPMC-SDS structure in the formulation. Copyright © 2017 Elsevier B.V. All rights reserved.

Kinetics of absorption and elimination of ofloxacin in humans after oral and rectal administrations.

PubMed

Eboka, C J; Okor, R S; Akerele, J O; Aigbavboa, S O

1997-06-01

Ofloxacin pharmacokinetics have been studied in four healthy subjects after a single oral or rectal dose, each of 200 mg. For the oral dose tmax was about 2 h, Cmax 1.96 +/- 0.56 micrograms/ml and AUC1-15 15.22 micrograms/ml.h. Two-phase elimination pharmacol kinetics were observed for the oral dose, t1/2 for the rapid elimination phase was 3.3 h and for the slow phase 10 h. With the rectal dose tmax was 6 h, Cmax 0.71 +/- 0.44 microgram/ml and AUC0-15 7.58 micrograms/ml.h. The relative rectal bioavailability (AUC rectal/AUC oral) was 49.8%. Elimination rate of the rectal dose was generally slow (t1/2 = 9 h), an observation attributable to the sustained-release effect of the rectal suppository base, PEG 6000. The indication is that the rectal formulation cannot be substituted totally for the oral without first increasing the rectal dose; the 200 mg suppository can however be employed as a follow-up therapy to the oral dose in certain situations.

Comparison of echocardiographic and pressure-volume loop indices of systolic function in patients with single ventricle physiology: a preliminary report.

PubMed

Butts, Ryan J; Chowdhury, Shahryar M; Buckley, Jason; Hlavacek, Anthony M; Hsia, Tain Yen; Khambadkone, Sachin; Baker, G Hamilton

2015-01-01

Differences in ventricular geometry and physiology of patients with single ventricle anatomy complicate the application of traditional, noninvasive measurements of systolic function. We compared noninvasive measures of ventricular systolic function in single ventricle patients with invasive measures to evaluate their validity in this population. A secondary analysis of patients with single ventricle physiology enrolled in the multi-institutional research project, "multi-scale modeling of single ventricle hearts," was performed. Pressure-volume loops (PVLs) were recorded using microconductance catheters. Transthoracic echocardiogram and cardiac magnetic resonance imaging were performed on the same day. PVL indices of systolic function including end-systolic elastance (Ees), maximal rate of pressure increase (dP/dTmax), and stroke work indexed to end-diastolic volume (SW/EDV) were compared with noninvasive measures, including echocardiographic myocardial performance index (MPI), rate of pressure rise (AV valve dP/dT), isovolumic acceleration, longitudinal shortening fraction (longSF), and fractional area change (FAC). Fifteen patients had PVLs available for analysis. Eleven had a dominant right ventricle, three were status poststage 1 repair, five had superior cavopulmonary anastomosis, and seven had a total cavopulmonary anastomosis. FAC correlated with Ees (r = 0.69, P < .01), SW/EDV (r = 0.64, P = .01), and dP/dTmax (r = 0.59, P = .03). LongSF correlated with dP/dTmax (r = 0.61, P = .02) MPI, AV valve dP/dT, and isovolumic acceleration did not correlate with pressure-volume loop indices of systolic function. Obtaining PVLs via microconductance catheters can reliably be performed in the single ventricle population and serve as a method to validate echocardiographic indices in this high-risk population. Of the echocardiographic variables, FAC showed the best correlation with PVL indices. Future studies controlling for stage of palliation should be performed to further validate echocardiographic measures of systolic function in this patient population. © 2014 Wiley Periodicals, Inc.

Folate bioavailability from foods rich in folates assessed in a short term human study using stable isotope dilution assays.

PubMed

Mönch, Sabine; Netzel, Michael; Netzel, Gabriele; Ott, Undine; Frank, Thomas; Rychlik, Michael

2015-01-01

Different sources of folate may have different bioavailability and hence may impact the standard definition of folate equivalents. In order to examine this, a short term human study was undertaken to evaluate the relative native folate bioavailabilities from spinach, Camembert cheese and wheat germs compared to pteroylmonoglutamic acid as the reference dose. The study had a single-centre, randomised, four-treatment, four-period, four-sequence, cross-over design, i.e. the four (food) items to be tested (referred to as treatments) were administered in sequences according to the Latin square, so that each experimental treatment occurred only once within each sequence and once within each study period. Each of the 24 subjects received the four experimental items separated by a 14-day equilibrium phase and received a pteroylmonoglutamic acid supplement for 14 days before the first testing and between the testings for saturation of body pools. Folates in test foods, plasma and urine samples were determined by stable isotope dilution assays, and in urine and plasma, the concentrations of 5-methyltetrahydrofolate were evaluated. Standard non-compartmental methods were applied to determine the biokinetic parameters C(max), t(max) and AUC from baseline corrected 5-methyltetrahydrofolate concentrations within the interval from 0 to 12 hours. The variability of AUC and C(max) was moderate for spinach and oral solution of pteroylmonoglutamic acid but high for Camembert cheese and very high for wheat germs. The median t(max) was lowest for spinach, though t(max) showed a high variability among all treatments. When comparing the ratio estimates of AUC and C(max) for the different test foods, highest bioavailability was found for spinach followed by that for wheat germs and Camembert cheese. The results underline the dependence of folate bioavailability on the type of food ingested. Therefore, the general assumption of 50% bioavailability as the rationale behind the definition of folate equivalents has to be questioned and requires further investigation.

Effects of negative pressures on epithelial tight junctions and migration in wound healing.

PubMed

Hsu, Chih-Chin; Tsai, Wen-Chung; Chen, Carl Pai-Chu; Lu, Yun-Mei; Wang, Jong-Shyan

2010-08-01

Negative-pressure wound therapy has recently gained popularity in chronic wound care. This study attempted to explore effects of different negative pressures on epithelial migration in the wound-healing process. The electric cell-substrate impedance sensing (ECIS) technique was used to create a 5 x 10(-4) cm(2) wound in the Madin-Darby canine kidney (MDCK) and human keratinocyte (HaCaT) cells. The wounded cells were cultured in a negative pressure incubator at ambient pressure (AP) and negative pressures of 75 mmHg (NP(75)), 125 mmHg (NP(125)), and 175 mmHg (NP(175)). The effective time (ET), complete wound healing time (T(max)), healing rate (R(heal)), cell diameter, and wound area over time at different pressures were evaluated. Traditional wound-healing assays were prepared for fluorescent staining of cells viability, cell junction proteins, including ZO-1 and E-cadherin, and actins. Amount of cell junction proteins at AP and NP(125) was also quantified. In MDCK cells, the ET (1.25 +/- 0.27 h), T(max) (1.76 +/- 0.32 h), and R(heal) (2.94 +/- 0.62 x 10(-4) cm(2)/h) at NP(125) were significantly (P < 0.01) different from those at three other pressure conditions. In HaCaT cells, the T(max) (7.34 +/- 0.29 h) and R(heal) (6.82 +/- 0.26 x 10(-5) cm(2)/h) at NP(125) were significantly (P < 0.01) different from those at NP(75). Prominent cell migration features were identified in cells at the specific negative pressure. Cell migration activities at different pressures can be documented with the real-time wound-healing measurement system. Negative pressure of 125 mmHg can help disassemble the cell junction to enhance epithelial migration and subsequently result in quick wound closure.

A Comparative Pharmacokinetics Study of the Anti-Parkinsonian Drug Pramipexole

PubMed Central

Putri, Ratih S. I.; Setiawati, Effi; Aziswan, Syifa A.; Ong, Fenny; Tjandrawinata, Raymond R.; Susanto, Liana W.

2016-01-01

The present study aimed to compare pharmacokinetic parameters of two pramipexole 0.25 mg formulations in order to show bioequivalence. The study was conducted in a randomized, open-label, two-period, two-sequence, and crossover design, involving 23 healthy volunteers. One of the 0.25 mg formulations of pramipexole evaluated in the study was manufactured by PT Dexa Medica, Palembang, Indonesia, the other, used as the reference, by Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim am Rhein, Germany. All eligible subjects were required to fast before each drug administration period, which was separated by a one-week washout period. Pramipexole concentrations in plasma were assayed using a validated ultra performance liquid chromatography with mass spectrometry (UPLC-MS/MS) detector. The evaluated pharmacokinetic parameters included the area under the plasma concentration curve from time zero to the last observed measurable concentration (AUC0-t), the area under the plasma concentration curve extrapolated to infinite time (AUC0-∞), the maximum plasma concentration (Cmax), the time to reach Cmax (tmax), and the plasma concentration half-life (t1/2). To evaluate the bioequivalence of those two pramipexole formulations, 90% confidence intervals (CIs) for geometric mean ratios of both formulations were calculated for AUC and Cmax parameters, while tmax and t1/2 differences were analyzed on the non-transformed data using Wilcoxon matched-pairs and a Student’s paired t-test, respectively. The 90% CIs for the geometric mean ratios of the two pramipexole formulations were 95.89% (90.73%–101.34%), 95.53% (89.75%–101.68%), and 92.11% (84.35%–100.58%) for AUC0-t, AUC0-∞, and Cmax, respectively. There were no statistically significant differences for tmax and t1/2 between the two pramipexole formulations. It is concluded that two pramipexole formulations in this study were bioequivalent. PMID:27869754

Dynamic Magnetic Resonance Angiography Provides Collateral Circulation and Hemodynamic Information in Acute Ischemic Stroke.

PubMed

Hernández-Pérez, María; Puig, Josep; Blasco, Gerard; Pérez de la Ossa, Natalia; Dorado, Laura; Dávalos, Antoni; Munuera, Josep

2016-02-01

Contrary to usual static vascular imaging techniques, contrast-enhanced dynamic magnetic resonance angiography (dMRA) enables dynamic study of cerebral vessels. We evaluated dMRA ability to assess arterial occlusion, cerebral hemodynamics, and collateral circulation in acute ischemic stroke. Twenty-five acute ischemic stroke patients with proximal anterior circulation occlusion underwent dMRA on a 3T scanner within 12 hours of symptoms onset. Diffusion weighted imaging, Tmax6 s lesion volumes and hypoperfusion intensity ratio as volume of Tmax>6 s/volume of Tmax>10 s were measured. Site and grade of occlusion (Thrombolysis in Myocardial Infarction criteria) were evaluated on time-of-flight MRA and dMRA. Leptomeningeal collaterality (American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology [ASITN/SIR] Scale) and asymmetries in venous clearance were assessed exclusively on dMRA. Collateral filling was dichotomized into incomplete (ASITN/SIR 0-2) or complete (ASITN/SIR 3-4). On dMRA, site of occlusion was M1 in 21 patients, tandem internal carotid artery/M1 in 2 and tandem internal carotid artery/terminal internal carotid artery in 2 patients. Three tandem occlusions were not detected on time-of-flight-MRA. All patients had Thrombolysis in Myocardial Infarction 0 to 1 on time-of-flight-MRA, but three of them had Thrombolysis in Myocardial Infarction 2 on dMRA. Complete collateral filling (n=12, 48%) was associated with smaller diffusion weighted imaging lesion volume (P=0.039), smaller hypoperfused volume (P=0.018), and lower hypoperfusion intensity ratio (P=0.006). Patients with symmetrical clearance of transverse sinuses (52%) were more likely to have complete collateral filling (P=0.015). As a fast, direct, feasible, noninvasive, and reliable method to assess site of occlusion, collateral circulation and hemodynamic alterations, dMRA provides profound insights in acute stroke. © 2015 American Heart Association, Inc.

[Simultaneous determination of daphnetin, daphnoretin, daphneticin in rat plasma by LC-MS/MS and its application in pharmacokinetic study].

PubMed

Hu, Yi-Yi-Li-Ge-Qi; Cao, Sa-Li; Lin, Long-Fei; Fu, Jing; Dong, Xiao-Xu; Yang, Chun-Jing; Zhang, Miao; Ni, Jian

2017-05-01

To establish HPLC-MS/MS method for simultaneous determination of daphnetin, daphnoretin, and daphneticin in rat plasma after oral and intravenous administration of Daphne giraldii extract, and then use them in the calculation of pharmacokinetic parameters. Six sprague-dawley rats received intragastric administration of D. giraldii extract (daphnetin, daphnoretin and daphneticin were 88.40, 3.24 and 4.28 mg•kg⁻¹, respectively). Their drug plasma concentration was determined by LC-MS/MS with schisandrin as an internal standard to draw plasma concentration-time curve. The pharmacokinetic parameters were calculated by Kinetica 4.4. The results showed that the linear range was 5-1 000 μg•L⁻¹ for daphnetin, daphnoretin and daphneticin, and the method ological test showed conformance to the requirements.The intraday and inter-day variable coefficients (RSD) were both less than 15.0%, indicating that both of legitimate precise and accuracy were consistent with the analysis requirements of biological samples. For daphnetin, the pharmacokinetic parameters Tmax, Cmax, AUC0-t, T1/2 and MRT were 4 h, 858.96 μg•L⁻¹, 10 566.4 μg•L⁻¹•h, 5.19 h and 9.43 h, respectively. For daphnoretin, the pharmacokinetic parameters Tmax, Cmax, AUC0-t, T1/2 and MRT were 2.92 h, 178.00 μg•L⁻¹, 905.89 μg•L⁻¹•h, 3.50 h and 6.95 h, respectively. For daphneticin, the pharmacokinetic parameters Tmax, Cmax, AUC0-t, T1/2 and MRT were 2 h, 36.67 μg•L⁻¹, 355.11 μg•L⁻¹•h, 4.95 h and 8.27 h, respectively. The LC-MS/MS analysis method established in this study was proved to be so accurate and sensitive that it can be applied to the pharmacokinetic study of daphnetin, daphnoretin and daphneticin. Copyright© by the Chinese Pharmaceutical Association.

Time-Dependent Computed Tomographic Perfusion Thresholds for Patients With Acute Ischemic Stroke.

PubMed

d'Esterre, Christopher D; Boesen, Mari E; Ahn, Seong Hwan; Pordeli, Pooneh; Najm, Mohamed; Minhas, Priyanka; Davari, Paniz; Fainardi, Enrico; Rubiera, Marta; Khaw, Alexander V; Zini, Andrea; Frayne, Richard; Hill, Michael D; Demchuk, Andrew M; Sajobi, Tolulope T; Forkert, Nils D; Goyal, Mayank; Lee, Ting Y; Menon, Bijoy K

2015-12-01

Among patients with acute ischemic stroke, we determine computed tomographic perfusion (CTP) thresholds associated with follow-up infarction at different stroke onset-to-CTP and CTP-to-reperfusion times. Acute ischemic stroke patients with occlusion on computed tomographic angiography were acutely imaged with CTP. Noncontrast computed tomography and magnectic resonance diffusion-weighted imaging between 24 and 48 hours were used to delineate follow-up infarction. Reperfusion was assessed on conventional angiogram or 4-hour repeat computed tomographic angiography. Tmax, cerebral blood flow, and cerebral blood volume derived from delay-insensitive CTP postprocessing were analyzed using receiver-operator characteristic curves to derive optimal thresholds for combined patient data (pooled analysis) and individual patients (patient-level analysis) based on time from stroke onset-to-CTP and CTP-to-reperfusion. One-way ANOVA and locally weighted scatterplot smoothing regression was used to test whether the derived optimal CTP thresholds were different by time. One hundred and thirty-two patients were included. Tmax thresholds of >16.2 and >15.8 s and absolute cerebral blood flow thresholds of <8.9 and <7.4 mL·min(-1)·100 g(-1) were associated with infarct if reperfused <90 min from CTP with onset <180 min. The discriminative ability of cerebral blood volume was modest. No statistically significant relationship was noted between stroke onset-to-CTP time and the optimal CTP thresholds for all parameters based on discrete or continuous time analysis (P>0.05). A statistically significant relationship existed between CTP-to-reperfusion time and the optimal thresholds for cerebral blood flow (P<0.001; r=0.59 and 0.77 for gray and white matter, respectively) and Tmax (P<0.001; r=-0.68 and -0.60 for gray and white matter, respectively) parameters. Optimal CTP thresholds associated with follow-up infarction depend on time from imaging to reperfusion. © 2015 American Heart Association, Inc.

Integrated Field Analyses of Thermal Springs

NASA Astrophysics Data System (ADS)

Shervais, K.; Young, B.; Ponce-Zepeda, M. M.; Rosove, S.

2011-12-01

A group of undergraduate researchers through the SURE internship offered by the Southern California Earthquake Center (SCEC) have examined thermal springs in southern Idaho, northern Utah as well as mud volcanoes in the Salton Sea, California. We used an integrated approach to estimate the setting and maximum temperature, including water chemistry, Ipad-based image and data-base management, microbiology, and gas analyses with a modified Giggenbach sampler.All springs were characterized using GISRoam (tmCogent3D). We are performing geothermometry calculations as well as comparisons with temperature gradient data on the results while also analyzing biological samples. Analyses include water temperature, pH, electrical conductivity, and TDS measured in the field. Each sample is sealed and chilled and delivered to a water lab within 12 hours.Temperatures are continuously monitored with the use of Solinst Levelogger Juniors. Through partnership with a local community college geology club, we receive results on a monthly basis and are able to process initial data earlier in order to evaluate data over a longer time span. The springs and mudpots contained microbial organisms which were analyzed using methods of single colony isolation, polymerase chain reaction, and DNA sequencing showing the impact of the organisms on the springs or vice versa. Soon we we will collect gas samples at sites that show signs of gas. This will be taken using a hybrid of the Giggenbach method and our own methods. Drawing gas samples has proven a challenge, however we devised a method to draw out gas samples utilizing the Giggenbach flask, transferring samples to glass blood sample tubes, replacing NaOH in the Giggenbach flask, and evacuating it in the field for multiple samples using a vacuum pump. We also use a floating platform devised to carry and lower a levelogger, to using an in-line fuel filter from a tractor in order to keep mud from contaminating the equipment.The use of raster imagery on the iPad2 has drastically changed how we plan and conduct our sampling trips. Orthoimagery onto the iPad2 is viewed with GISRoam and we use that imagery to help guide us toward points that we wish to visit. GISRoam was used to plot spatially correlated data points while in the field, estimate latitude and longitude, and record aforementioned data. A key factor to our success is up to the minute collaboration between all participants. Google's suite of services provides phone number for landowners, web site hosting, and the most crucial implementation for sharing data in real time has been the beta google Fusion Table. This spreadsheet allows for the incorporation of images, sample data and GPS location to be displayed as a kml file to be viewed in Google maps. This ability to modify and recognize data points in real time has made us more effective in the field, and in documenting progress in the lab. This workflow has enabled us to sample over 30 springs in 2 months, find 10 new springs, and estimate Tmax for 14 sites.By the end of 3 months we anticipate having water chemistry, isotope samples, gas samples, and Tmax determinations for 30 springs in the two study areas.

Multiple comparisons permutation test for image based data mining in radiotherapy

PubMed Central

2013-01-01

Comparing incidental dose distributions (i.e. images) of patients with different outcomes is a straightforward way to explore dose-response hypotheses in radiotherapy. In this paper, we introduced a permutation test that compares images, such as dose distributions from radiotherapy, while tackling the multiple comparisons problem. A test statistic Tmax was proposed that summarizes the differences between the images into a single value and a permutation procedure was employed to compute the adjusted p-value. We demonstrated the method in two retrospective studies: a prostate study that relates 3D dose distributions to failure, and an esophagus study that relates 2D surface dose distributions of the esophagus to acute esophagus toxicity. As a result, we were able to identify suspicious regions that are significantly associated with failure (prostate study) or toxicity (esophagus study). Permutation testing allows direct comparison of images from different patient categories and is a useful tool for data mining in radiotherapy. PMID:24365155

Relativistic equipartition via a massive damped sliding partition

NASA Astrophysics Data System (ADS)

Crawford, Frank S.

1993-04-01

A cylinder partitioned by a massive sliding slab undergoing nonrelativistic damped one-dimensional (1D) motion under bombardment from the left (i=1) and right (i=2) by particles having rest mass mi, speed vi, relativistic momentum (magnitude) pi, and (let c≡1) total energy Ei=(pi2+mi2)1/2 is considered herein. The damped slab of mass M transforms the system from its initial pi distributions (i=1,2) to a state, first, of pressure (P) equilibrium with P1=P2, but temperature T1≠T2, then, to P-T equilibrium with P1=P2 and T1=T2, given by the (1D) ``first moment'' equipartition relation (κ is Boltzmann's constant),

A digital sedimentator for measuring erythrocyte sedimentation rate using a linear image sensor

NASA Astrophysics Data System (ADS)

Yoshikoshi, Akio; Sakanishi, Akio; Toyama, Yoshiharu

2004-11-01

A digital apparatus was fabricated to determine accurately the erythrocyte sedimentation rate (ESR) using a linear image sensor. Currently, ESR is utilized for clinical diagnosis, and in the laboratory as one of the many rheological properties of blood through the settling of red blood cells (RBCs). In this work, we aimed to measure ESR automatically using a small amount of a sample and without moving parts. The linear image sensor was placed behind a microhematocrit tube containing 36 μl of RBC suspension on a holder plate; the holder plate was fixed on an optical bench together with a tungsten lamp and an opal glass placed in front. RBC suspensions were prepared in autologous plasma with hematocrit H from 25% to 44%. The intensity profiles of transmitted light in 36 μl of RBC suspension were detected using the linear image sensor and sent to a personal computer every minute. ESR was observed at the settling interface between the plasma and RBC suspension in the profile in 1024 pixels (25 μm/pixel) along a microhematocrit tube of 25.6 mm total length for 1 h at a temperature of 37.0±0.1 °C. First, we determined the initial pixel position of the sample at the boundary with air. The boundary and the interface were defined by inflection points in the profile with 25 μm resolution. We obtained sedimentation curves that were determined by the RBC settling distance l(t) at the time t from the difference between pixel locations at the boundary and the interface. The sedimentation curves were well fitted to an empirical equation [Puccini et al., Biorheol. 14, 43 (1977)] from which we calculated the maximum sedimentation velocity smax at the time tmax. We reached tmax within 30 min at any H, and smax linearly related to the settling distance l(60) at 60 min after the start of sedimentation from 30% to 44% H with the correlation coefficient r=0.993. Thus, we may estimate conventional ESR at 1 h from smax more quickly and accurately with less effort.

Modelling uncertainties and possible future trends of precipitation and temperature for 10 sub-basins in Columbia River Basin (CRB)

NASA Astrophysics Data System (ADS)

Ahmadalipour, A.; Rana, A.; Qin, Y.; Moradkhani, H.

2014-12-01

Trends and changes in future climatic parameters, such as, precipitation and temperature have been a central part of climate change studies. In the present work, we have analyzed the seasonal and yearly trends and uncertainties of prediction in all the 10 sub-basins of Columbia River Basin (CRB) for future time period of 2010-2099. The work is carried out using 2 different sets of statistically downscaled Global Climate Model (GCMs) projection datasets i.e. Bias correction and statistical downscaling (BCSD) generated at Portland State University and The Multivariate Adaptive Constructed Analogs (MACA) generated at University of Idaho. The analysis is done for with 10 GCM downscaled products each from CMIP5 daily dataset totaling to 40 different downscaled products for robust analysis. Summer, winter and yearly trend analysis is performed for all the 10 sub-basins using linear regression (significance tested by student t test) and Mann Kendall test (0.05 percent significance level), for precipitation (P), temperature maximum (Tmax) and temperature minimum (Tmin). Thereafter, all the parameters are modelled for uncertainty, across all models, in all the 10 sub-basins and across the CRB for future scenario periods. Results have indicated in varied degree of trends for all the sub-basins, mostly pointing towards a significant increase in all three climatic parameters, for all the seasons and yearly considerations. Uncertainty analysis have reveled very high change in all the parameters across models and sub-basins under consideration. Basin wide uncertainty analysis is performed to corroborate results from smaller, sub-basin scale. Similar trends and uncertainties are reported on the larger scale as well. Interestingly, both trends and uncertainties are higher during winter period than during summer, contributing to large part of the yearly change.

Gastrointestinal temperature trends in football linemen during physical exertion under heat stress.

PubMed

Coris, Eric E; Mehra, Shabnam; Walz, Stephen M; Duncanson, Robert; Jennings, Jason; Nugent, Dylan; Zwygart, Kira; Pescasio, Michele

2009-06-01

Exertional heat stroke is the third leading cause of death in US athletes. Elevations in core temperature in the digestive tract (TGI) have correlated with core temperature and are possible indicators of those at increased risk of heat stroke. The primary objective was to compare a.m. vs. p.m. TGI variation in collegiate football linemen during intense "two-a-day" preseason practice. A secondary objective was to compare longitudinal TGI in offensive and defensive linemen. Cross-sectional observational study. Division I Intercollegiate Athletics Football Program. TGI was monitored during consecutive preseason sessions. TGI, heat illness, weight changes, environmental stress, and subjective symptoms. Mean TGI were 37.8°C and 38.3°C during a.m. and p.m. practices, respectively. The a.m. practices revealed higher TGI gain (1.8°C) compared to p.m. (1.4°C). The p.m. practices had higher maximum TGI than a.m. practices (39.1°C versus 38.8, P=0.0001). Mean time to maximum temperature (Tmax) was 1 hr and 30 min for a.m. and 1 hr and 22 min for p.m. practices. Offensive linemen trended toward higher mean TGI than defensive players (38.0°C vs. 36.7°C, P = 0.069). The rate of rise in TGI was significantly greater in a.m. practices. A decrease in rate of TGI rise was seen from the first to last a.m. practices of the week (P = 0.004). Significant TGI elevations in asymptomatic athletes are common in extreme heat during football practice. Intense a.m. practices in full gear result in higher net temperature gain and rate of temperature gain than p.m. practices. Offensive linemen trended toward higher TGI than defensive linemen. As players acclimatized, a decrease in the rate of TGI increase was appreciable, particularly in a.m. practices. Appreciating cumulative heat stress and variations in heat stress related to scheduling of practice is critical.

Body temperature changes are associated with outcomes following in-hospital cardiac arrest and return of spontaneous circulation.

PubMed

Suffoletto, Brian; Peberdy, Mary Anne; van der Hoek, Terry; Callaway, Clifton

2009-12-01

Spontaneous changes in body temperature after return of circulation (ROSC) from cardiac arrest are common, but the association of these changes with outcomes in hospitalized patients who survive to 24h post-ROSC is not known. We tested the hypothesis that adults who experience temperature lability in the first 24h have worse outcomes compared with those who maintain normothermia. A prospective observational study from a multicenter registry of cardiac arrests (National Registry of Cardiopulmonary Resuscitation) from 355 US and Canadian hospitals. 14,729 adults with return of circulation from a pulseless cardiac arrest. We excluded those who died or were discharged before 24h post-event, those made Do-Not-Resuscitate (DNR) within 24h of event, those that had a preceding trauma, and those with multiple cardiac arrests. Finally, we included only subjects that had both a lowest (T(min)) and highest (T(max)) body temperature value recorded during the first 24-h after ROSC, resulting in a study sample of 3426 patients. After adjustment for potential covariates, there was a lower odds of survival in those having an episode of hypothermia (adjusted odds ratio [OR], 0.62; 95% confidence interval [CI], 0.48-0.80), those having an episode of hyperthermia (OR, 0.67; 95% CI, 0.48-0.80), and those having an episode of both (OR, 0.59; 95% CI, 0.39-0.91). Among those who survived to discharge, there was also a lower odds of favorable neurologic performance in those who had an episode of hyperthermia (OR, 0.71; 95% CI, 0.51-0.98). Episodes of temperature lability following in-hospital resuscitation from cardiac arrest are associated with lower odds of surviving to discharge. Hyperthermia is also associated with fewer patients leaving the hospital with favorable neurologic performance. Further studies should identify whether therapeutic control over changes in body temperature after in-hospital cardiac arrest improves outcomes.

Organic matter variations in transgressive and regressive shales

USGS Publications Warehouse

Pasley, M.A.; Gregory, W.A.; Hart, G.F.

1991-01-01

Organic matter in the Upper Cretaceous Mancos Shale adjacent to the Tocito Sandstone in the San Juan Basin of New Mexico was characterized using organic petrology and organic geochemistry. Differences in the organic matter found in these regressive and transgressive offshore marine sediments have been documented and assessed within a sequence stratigraphic framework. The regressive Lower Mancos Shale below the Tocito Sandstone contains abundant well preserved phytoclasts and correspondingly low hydrogen indices. Total organic carbon values for the regressive shale are low. Sediments from the transgressive systems tract (Tocito Sandstone and overlying Upper Mancos Shale) contain less terrestrially derived organic matter, more amorphous non-structured protistoclasts, higher hydrogen indices and more total organic carbon. Advanced stages of degradation are characteristic of the phytoclasts found in the transgressive shale. Amorphous material in the transgressive shale fluoresces strongly while that found in the regressive shale is typically non-fluorescent. Data from pyrolysis-gas chromatography confirm these observations. These differences are apparently related to the contrasting depositional styles that were active on the shelf during regression and subsequent transgression. It is suggested that data from organic petrology and organic geochemistry provide greater resolution in sedimentologic and stratigraphic interpretations, particularly when working with basinward, fine-grained sediments. Petroleum source potential for the regressive Lower Mancos Shale below the Tocito Sandstone is poor. Based on abundant fluorescent amorphous material, high hydrogen indices, and high total organic carbon, the transgressive Upper Mancos Shale above the Tocito Sandstone possesses excellent source potential. This suggests that appreciable source potential can be found in offshore, fine-grained sediments of the transgressive systems tract below the condensed section and associated downlap surface. Organic petrology can be used to accurately predict petroleum source potential. The addition of simple fluorescence microscopy greatly enhances this predictive ability because non-generative amorphous material is generally non-fluorescent. Organic petrology must also be used to properly evaluate the utility of Tmax from programmed pyrolysis as a thermal maturity indicator. Organic matter dominated by autochthonous amorphous protistoclasts exhibits lower Tmax values than that which is composed of mostly phytoclasts. ?? 1991.

Pharmacokinetics of gabapentin in a novel gastric-retentive extended-release formulation: comparison with an immediate-release formulation and effect of dose escalation and food.

PubMed

Chen, Cuiping; Cowles, Verne E; Hou, Eddie

2011-03-01

The objectives of the 3 phase I studies described herein were (1) to compare the pharmacokinetics of gabapentin delivered from a novel gastric-retentive dosage form vs an immediate-release formulation, (2) to assess the dose proportionality of the gastric-retentive extended-release formulation, and (3) to determine the effect of food on the pharmacokinetics of gabapentin delivered from this formulation. The time to reach maximum plasma concentration (t(max)) was extended for gabapentin delivered from the gastric-retentive extended-release formulation compared with the immediate-release formulation. A dose-related increase in both the maximum plasma concentration (C(max)) and the area under the plasma concentration-time curve (AUC) was observed as the gabapentin dose increased from 600 to 2400 mg. Fed status and increased fat content delayed t(max) and enhanced C(max) and AUC in proportion to the fat content. The pharmacokinetics of gabapentin delivered from this extended-release formulation allows a reduced dosing frequency while maintaining bioavailability and possibly diminishing the occurrence of adverse events attributable to a slower increase to the peak concentration compared with the immediate-release dosage form.

Evaluating the Energy Recovery Potential of Nigerian Coals under Non-Isothermal Thermogravimetry

NASA Astrophysics Data System (ADS)

Bevan Nyakuma, Bemgba; Oladokun, Olagoke; Jauro, Aliyu; Damian Nyakuma, Denen

2017-07-01

This study investigated the fuel properties and energy recovery potential of two coal samples from Ihioma (IHM) and Ogboligbo (OGB) environs in Nigeria. The ultimate, proximate, and bomb calorimetric analyses of the coal were examined. Next, the rank classification and potential application of the coals were evaluated according to the ASTM standard D388. Lastly, thermal decomposition behaviour was examined by non-isothermal thermogravimetry (TG) under pyrolysis conditions from 30 - 900 °C. The results indicated IHM and OGB contain high proportions of combustible elements for potential thermal conversion. The higher heating value (HHV) of IHM was 20.37 MJ/kg whereas OGB was 16.33 MJ/kg. TG analysis revealed 55% weight loss for OGB and 76% for IHM. The residual mass was 23% for IHM and 44% for OGB. Based on the temperature profile characteristics (TPCs); Ton , Tmax , and Toff , IHM was more reactive than OGB due to its higher volatile matter (VM). Overall, results revealed the coals are Lignite (Brown) low-rank coals (LRCs) with potential for electric power generation.

On ultraviolet freeze-in dark matter during reheating

NASA Astrophysics Data System (ADS)

Chen, Shao-Long; Kang, Zhaofeng

2018-05-01

The absence of any confirmative signals from extensive DM searching motivates us to go beyond the conventional WIMPs scenario. The feebly interacting massive particles (FIMPs) paradigm provides a good alternative which, despite of its feebly interaction with the thermal particles, still could correctly produce relic abundance without conventional DM signals. The Infrared-FIMP based on the renormalizable operators is usually suffering the very tiny coupling drawback, which can be overcome in the UltraViolet-FIMP scenario based on high dimensional effective operators. However, it is sensitive to the history of the very early Universe. The previous works terminates this sensitivity at the reheating temperature TRH. We, motivated by its UV-sensitivity, investigate the effects from the even earlier Universe, reheating era. We find that in the usual case with TRHgg mDM, the production rate during reheating is very small as long as the effective operators dimension d <= 8. Besides, we consider the contribution from the mediator, which may be produced during reheating. Moreover, we study the situation when TRH is even lower than mDM and DM can be directly produced during reheating if its mass does not exceed TMAX.

RM-DEMATEL: a new methodology to identify the key factors in PM2.5.

PubMed

Chen, Yafeng; Liu, Jie; Li, Yunpeng; Sadiq, Rehan; Deng, Yong

2015-04-01

Weather system is a relative complex dynamic system, the factors of the system are mutually influenced PM2.5 concentration. In this paper, a new method is proposed to quantify the influence on PM2.5 by other factors in the weather system and identify the most important factors for PM2.5 with limited resources. The relation map (RM) is used to figure out the direct relation matrix of 14 factors in PM2.5. The decision making trial and evaluation laboratory(DEMATEL) is applied to calculate the causal relationship and extent to a mutual influence of 14 factors in PM2.5. According to the ranking results of our proposed method, the most important key factors is sulfur dioxide (SO2) and nitrogen oxides (NO(X)). In addition, the other factors, the ambient maximum temperature (T(max)), concentration of PM10, and wind direction (W(dir)), are important factors for PM2.5. The proposed method can also be applied to other environment management systems to identify key factors.

Physicochemical characterization of diclofenac sodium-loaded poloxamer gel as a rectal delivery system with fast absorption.

PubMed

Yong, Chul Soon; Sah, Hongkee; Jahng, Yurngdong; Chang, Hyeun Wook; Son, Jong-Keun; Lee, Seung Ho; Jeong, Tae Cheon; Rhee, Jong-Dal; Baek, Suk Hwan; Kim, Chong-Kook; Choi, Han-Gon

2003-05-01

Rectal poloxamer gel systems composed of poloxamers and bioadhesive polymers were easy to administer to the anus and were mucoadhesive to the rectal tissues without leakage after the dose. However, a poloxamer gel containing diclofenac sodium could not be developed using bioadhesive polymers, since the drug was precipitated in this preparation. To develop a poloxamer gel using sodium chloride instead of bioadhesive polymers, the physicochemical properties such as gelation temperature, gel strength, and bioadhesive force of various formulations composed of diclofenac sodium, poloxamers, and sodium chloride were investigated. Furthermore, the pharmacokinetic study of diclofenac sodium delivered by the poloxamer gel was performed. Diclofenac sodium significantly increased the gelation temperature and weakened the gel strength and bioadhesive force, while sodium chloride did the opposite. The poloxamer gels with less than 1.0% sodium chloride, in which the drug was not precipitated, were inserted into the rectum without difficulty and leakage, and were retained in the rectum of rats for at least 6 hr. Furthermore, poloxamer gel gave significantly higher initial plasma concentrations and faster Tmax of diclofenac sodium than did solid suppository, indicating that drug from poloxamer gel could be absorbed faster than that from the solid one in rats. Our results suggested that a rectal poloxamer gel system with sodium chloride and poloxamers was a more physically stable, convenient, and effective rectal dosage form for diclofenac sodium.

A comparative climate analysis of heat-related emergency 911 dispatches: Chicago, Illinois and Phoenix, Arizona USA 2003 to 2006.

PubMed

Hartz, Donna A; Brazel, Anthony J; Golden, Jay S

2013-09-01

Research into the health impacts of heat has proliferated since 2000. Temperature increases could exacerbate the increased heat already experienced by urban populations due to urbanization. Heat-related mortality studies have found that hot southern cities in North America have not experienced the summer increases in mortality found in their more northern counterparts. Heat-related morbidity studies have not assessed this possible regional difference. This comparison study uses data from emergency 911 dispatches [referred to as heat-related dispatches (HRD)] identified by responders as heat-related for two United States cities located in different regions with very different climates: Chicago, Illinois in the upper midwest and Phoenix, Arizona in the southwest. Phoenix's climate is hot and arid. Chicago's climate is more temperate, but can also experience days with unusually high temperatures combined with high humidity. This study examines the relationships between rising HRD and daily temperatures: maximum (Tmax); apparent (ATmax): minimum (Tmin) and two energy balance indices (PET and UTCI). Phoenix had more HRD cumulatively, over a longer warm weather season, but did not experience the large spikes in HRD that occurred in Chicago, even though it was routinely subjected to much hotter weather conditions. Statistical analyses showed the strongest relationships to daily ATmax for both cities. Phoenix's lack of HRD spikes, similar to the summer mortality patterns for southern cities, suggests an avenue for future research to better understand the dynamics of possible physiological or behavioral adaption that seems to reduce residents' vulnerability to heat.

A comparative climate analysis of heat-related emergency 911 dispatches: Chicago, Illinois and Phoenix, Arizona USA 2003 to 2006

NASA Astrophysics Data System (ADS)

Hartz, Donna A.; Brazel, Anthony J.; Golden, Jay S.

2013-09-01

Research into the health impacts of heat has proliferated since 2000. Temperature increases could exacerbate the increased heat already experienced by urban populations due to urbanization. Heat-related mortality studies have found that hot southern cities in North America have not experienced the summer increases in mortality found in their more northern counterparts. Heat-related morbidity studies have not assessed this possible regional difference. This comparison study uses data from emergency 911 dispatches [referred to as heat-related dispatches (HRD)] identified by responders as heat-related for two United States cities located in different regions with very different climates: Chicago, Illinois in the upper midwest and Phoenix, Arizona in the southwest. Phoenix's climate is hot and arid. Chicago's climate is more temperate, but can also experience days with unusually high temperatures combined with high humidity. This study examines the relationships between rising HRD and daily temperatures: maximum (Tmax); apparent (ATmax): minimum (Tmin) and two energy balance indices (PET and UTCI). Phoenix had more HRD cumulatively, over a longer warm weather season, but did not experience the large spikes in HRD that occurred in Chicago, even though it was routinely subjected to much hotter weather conditions. Statistical analyses showed the strongest relationships to daily ATmax for both cities. Phoenix's lack of HRD spikes, similar to the summer mortality patterns for southern cities, suggests an avenue for future research to better understand the dynamics of possible physiological or behavioral adaption that seems to reduce residents' vulnerability to heat.

Global quantitative indices reflecting provider process-of-care: data-base derivation.

PubMed

Moran, John L; Solomon, Patricia J

2010-04-19

Controversy has attended the relationship between risk-adjusted mortality and process-of-care. There would be advantage in the establishment, at the data-base level, of global quantitative indices subsuming the diversity of process-of-care. A retrospective, cohort study of patients identified in the Australian and New Zealand Intensive Care Society Adult Patient Database, 1993-2003, at the level of geographic and ICU-level descriptors (n = 35), for both hospital survivors and non-survivors. Process-of-care indices were established by analysis of: (i) the smoothed time-hazard curve of individual patient discharge and determined by pharmaco-kinetic methods as area under the hazard-curve (AUC), reflecting the integrated experience of the discharge process, and time-to-peak-hazard (TMAX, in days), reflecting the time to maximum rate of hospital discharge; and (ii) individual patient ability to optimize output (as length-of-stay) for recorded data-base physiological inputs; estimated as a technical production-efficiency (TE, scaled [0,(maximum)1]), via the econometric technique of stochastic frontier analysis. For each descriptor, multivariate correlation-relationships between indices and summed mortality probability were determined. The data-set consisted of 223129 patients from 99 ICUs with mean (SD) age and APACHE III score of 59.2(18.9) years and 52.7(30.6) respectively; 41.7% were female and 45.7% were mechanically ventilated within the first 24 hours post-admission. For survivors, AUC was maximal in rural and for-profit ICUs, whereas TMAX (>or= 7.8 days) and TE (>or= 0.74) were maximal in tertiary-ICUs. For non-survivors, AUC was maximal in tertiary-ICUs, but TMAX (>or= 4.2 days) and TE (>or= 0.69) were maximal in for-profit ICUs. Across descriptors, significant differences in indices were demonstrated (analysis-of-variance, P

Prediction of Tissue Outcome and Assessment of Treatment Effect in Acute Ischemic Stroke Using Deep Learning.

PubMed

Nielsen, Anne; Hansen, Mikkel Bo; Tietze, Anna; Mouridsen, Kim

2018-06-01

Treatment options for patients with acute ischemic stroke depend on the volume of salvageable tissue. This volume assessment is currently based on fixed thresholds and single imagine modalities, limiting accuracy. We wish to develop and validate a predictive model capable of automatically identifying and combining acute imaging features to accurately predict final lesion volume. Using acute magnetic resonance imaging, we developed and trained a deep convolutional neural network (CNN deep ) to predict final imaging outcome. A total of 222 patients were included, of which 187 were treated with rtPA (recombinant tissue-type plasminogen activator). The performance of CNN deep was compared with a shallow CNN based on the perfusion-weighted imaging biomarker Tmax (CNN Tmax ), a shallow CNN based on a combination of 9 different biomarkers (CNN shallow ), a generalized linear model, and thresholding of the diffusion-weighted imaging biomarker apparent diffusion coefficient (ADC) at 600×10 -6 mm 2 /s (ADC thres ). To assess whether CNN deep is capable of differentiating outcomes of ±intravenous rtPA, patients not receiving intravenous rtPA were included to train CNN deep, -rtpa to access a treatment effect. The networks' performances were evaluated using visual inspection, area under the receiver operating characteristic curve (AUC), and contrast. CNN deep yields significantly better performance in predicting final outcome (AUC=0.88±0.12) than generalized linear model (AUC=0.78±0.12; P =0.005), CNN Tmax (AUC=0.72±0.14; P <0.003), and ADC thres (AUC=0.66±0.13; P <0.0001) and a substantially better performance than CNN shallow (AUC=0.85±0.11; P =0.063). Measured by contrast, CNN deep improves the predictions significantly, showing superiority to all other methods ( P ≤0.003). CNN deep also seems to be able to differentiate outcomes based on treatment strategy with the volume of final infarct being significantly different ( P =0.048). The considerable prediction improvement accuracy over current state of the art increases the potential for automated decision support in providing recommendations for personalized treatment plans. © 2018 American Heart Association, Inc.

Impaired T-wave amplitude adaptation to heart-rate induced by cardiac deconditioning after 5-days of head-down bed-rest

NASA Astrophysics Data System (ADS)

Caiani, Enrico G.; Pellegrini, Alessandro; Bolea, Juan; Sotaquira, Miguel; Almeida, Rute; Vaïda, Pierre

2013-10-01

The study of QT/RR relationship is important for the clinical evaluation of possible risk of acquired or congenital ventricular tachyarrhythmias. In the hypothesis that microgravity exposure could induce changes in the repolarization mechanisms, our aim was to test if a short 5-days strict 6° head-down bed-rest (HDBR) could induce alterations in the QT/RR relationship and spatial repolarization heterogeneity. Twenty-two healthy men (mean age 31±6) were enrolled as part of the European Space Agency HDBR studies. High fidelity (1000 Hz) 24 h Holter ECG (12-leads, Mortara Instrument) was acquired before (PRE), the last day of HDBR (HDT5), and four days after its conclusion (POST). The night period (23:00-06:30) was selected for analysis. X, Y, Z leads were derived and the vectorcardiogram computed. Selective beat averaging was used to obtain averages of P-QRS-T complexes preceded by the same RR (10 ms bin amplitude, in the range 900-1200 ms). For each averaged waveform (i.e., one for each bin), T-wave maximum amplitude (Tmax), T-wave area (Tarea), RTapex, RTend, ventricular gradient (VG) magnitude and spatial QRS-T angle were computed. Non-parametric Friedman test was applied. Compared to PRE, at HDT5 both RTapex and RTend resulted shortened (-4%), with a decrease in T-wave amplitude (-8%) and area (-13%). VG was diminished by 10%, and QRS-T angle increased by 14°. At POST, QT duration and area parameters, as well as QRS-T angle were restored while Tmax resulted larger than PRE (+5%) and VG was still decreased by 3%. Also, a marked loss in strength of the linear regression with RR was found at HDT5 in Tmax and Tarea, that could represent a new dynamic marker of increased risk for life-threatening arrhythmias. Despite the short-term HDBR, ventricular repolarization during the night period was affected. This should be taken into account in astronauts for risk assessment during space flight.

SU-D-18C-02: Feasibility of Using a Short ASL Scan for Calibrating Cerebral Blood Flow Obtained From DSC-MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, P; Chang, T; Huang, K

2014-06-01

Purpose: This study aimed to evaluate the feasibility of using a short arterial spin labeling (ASL) scan for calibrating the dynamic susceptibility contrast- (DSC-) MRI in a group of patients with internal carotid artery stenosis. Methods: Six patients with unilateral ICA stenosis enrolled in the study on a 3T clinical MRI scanner. The ASL-cerebral blood flow (-CBF) maps were calculated by averaging different number of dynamic points (N=1-45) acquired by using a Q2TIPS sequence. For DSC perfusion analysis, arterial input function was selected to derive the relative cerebral blood flow (rCBF) map and the delay (Tmax) map. Patient-specific CF wasmore » calculated from the mean ASL- and DSC-CBF obtained from three different masks: (1)Tmax< 3s, (2)combined gray matter mask with mask 1, (3)mask 2 with large vessels removed. One CF value was created for each number of averages by using each of the three masks for calibrating the DSC-CBF map. The CF value of the largest number of averages (NL=45) was used to determine the acceptable range(< 10%, <15%, and <20%) of CF values corresponding to the minimally acceptable number of average (NS) for each patient. Results: Comparing DSC CBF maps corrected by CF values of NL (CBFL) in ACA, MCA and PCA territories, all masks resulted in smaller CBF on the ipsilateral side than the contralateral side of the MCA territory(p<.05). The values obtained from mask 1 were significantly different than the mask 3(p<.05). Using mask 3, the medium values of Ns were 4(<10%), 2(<15%) and 2(<20%), with the worst case scenario (maximum Ns) of 25, 4, and 4, respectively. Conclusion: This study found that reliable calibration of DSC-CBF can be achieved from a short pulsed ASL scan. We suggested use a mask based on the Tmax threshold, the inclusion of gray matter only and the exclusion of large vessels for performing the calibration.« less

Gender Difference of Gastric Emptying in Healthy Volunteers and Patients with Functional Dyspepsia.

PubMed

Mori, Hideki; Suzuki, Hidekazu; Matsuzaki, Juntaro; Taniguchi, Kanami; Shimizu, Toshiyuki; Yamane, Tsuyoshi; Masaoka, Tatsuhiro; Kanai, Takanori

2017-01-01

Delayed gastric emptying is one of the reasons why functional dyspepsia (FD) occurs. The 13C-acetate breath test is widely used to evaluate gastric emptying. Nevertheless, the standard value of 13C-acetate breath test has not taken into account the gender difference of gastric emptying among healthy individuals. The main aim of this study was to readjust the standard value of 13C-acetate breath test in the light of gender differences. In addition, we clarified the prevalence and clinical characteristics of delayed gastric emptying in patients with FD using the modified standard values of 13C-acetate breath test. Fifty-two healthy individuals and 126 patients with patients with FD were enrolled. Gastric emptying was evaluated by the 13C-acetate breath test. The cut-off points of Tmax for the diagnosis of delayed gastric emptying were determined on the basis of results from healthy individuals making a distinction of genders. Gastroesophageal reflux symptoms, dyspeptic symptoms, scores of anxiety and depression, age, body mass index (BMI), smoking and alcohol consumption were compared between the delayed gastric emptying group and the non-delayed gastric emptying group. Since gastric emptying was delayed in healthy women compared with that in healthy men (Tmax, 53.6 ± 19.3 vs. 42.7 ± 16.9 min, p = 0.04), we set the cut-off points of Tmax at 60 min in men and at 75 min in women. In patients with FD, the prevalence of delayed gastric emptying was not different between men and women with the modified standard values of 13C-acetate breath test. (31.0 vs. 27.4%, p = 0.68). BMI was lower in the delayed gastric emptying group than in the non-delayed group among the male patients. Reflux symptoms were more severe in delayed gastric emptying group than in the non-delayed group among the female patients. The standard values of 13C-acetate breath test should be modified bearing the gender difference in mind. It provides us more appropriate information to understand the mechanisms of FD. © 2016 S. Karger AG, Basel.

Bioavailability of ibuprofen following oral administration of standard ibuprofen, sodium ibuprofen or ibuprofen acid incorporating poloxamer in healthy volunteers

PubMed Central

2009-01-01

Background The aim of this study was to compare the pharmacokinetic properties of sodium ibuprofen and ibuprofen acid incorporating poloxamer with standard ibuprofen acid tablets. Methods Twenty-two healthy volunteers were enrolled into this randomised, single-dose, 3-way crossover, open-label, single-centre, pharmacokinetic study. After 14 hours' fasting, participants received a single dose of 2 × 200 mg ibuprofen acid tablets (standard ibuprofen), 2 × 256 mg ibuprofen sodium dihydrate tablets (sodium ibuprofen; each equivalent to 200 mg ibuprofen acid) and 2 × 200 mg ibuprofen acid incorporating 60 mg poloxamer 407 (ibuprofen/poloxamer). A washout period of 2-7 days separated consecutive dosing days. On each of the 3 treatment days, blood samples were collected post dose for pharmacokinetic analyses and any adverse events recorded. Plasma concentration of ibuprofen was assessed using a liquid chromatographic-mass spectrometry procedure in negative ion mode. A standard statistical ANOVA model, appropriate for bioequivalence studies, was used and ratios of 90% confidence intervals (CIs) were calculated. Results Tmax for sodium ibuprofen was less than half that of standard ibuprofen (median 35 min vs 90 min, respectively; P = 0.0002) and Cmax was significantly higher (41.47 μg/mL vs 31.88 μg/mL; ratio test/reference = 130.06%, 90% CI 118.86-142.32%). Ibuprofen/poloxamer was bioequivalent to the standard ibuprofen formulation, despite its Tmax being on average 20 minutes shorter than standard ibuprofen (median 75 mins vs 90 mins, respectively; P = 0.1913), as the ratio of test/reference = 110.48% (CI 100.96-120.89%), which fell within the 80-125% limit of the CPMP and FDA guidelines for bioequivalence. The overall extent of absorption was similar for the three formulations, which were all well tolerated. Conclusion In terms of Tmax, ibuprofen formulated as a sodium salt was absorbed twice as quickly as from standard ibuprofen acid. The addition of poloxamer to ibuprofen acid did not significantly affect absorption. PMID:19961574

A critical remark on the applicability of E-OBS European gridded temperature data set for validating control climate simulations

NASA Astrophysics Data System (ADS)

Kyselý, Jan; Plavcová, Eva

2010-12-01

The study compares daily maximum (Tmax) and minimum (Tmin) temperatures in two data sets interpolated from irregularly spaced meteorological stations to a regular grid: the European gridded data set (E-OBS), produced from a relatively sparse network of stations available in the European Climate Assessment and Dataset (ECA&D) project, and a data set gridded onto the same grid from a high-density network of stations in the Czech Republic (GriSt). We show that large differences exist between the two gridded data sets, particularly for Tmin. The errors tend to be larger in tails of the distributions. In winter, temperatures below the 10% quantile of Tmin, which is still far from the very tail of the distribution, are too warm by almost 2°C in E-OBS on average. A large bias is found also for the diurnal temperature range. Comparison with simple average series from stations in two regions reveals that differences between GriSt and the station averages are minor relative to differences between E-OBS and either of the two data sets. The large deviations between the two gridded data sets affect conclusions concerning validation of temperature characteristics in regional climate model (RCM) simulations. The bias of the E-OBS data set and limitations with respect to its applicability for evaluating RCMs stem primarily from (1) insufficient density of information from station observations used for the interpolation, including the fact that the stations available may not be representative for a wider area, and (2) inconsistency between the radii of the areal average values in high-resolution RCMs and E-OBS. Further increases in the amount and quality of station data available within ECA&D and used in the E-OBS data set are essentially needed for more reliable validation of climate models against recent climate on a continental scale.

The detection and quantification of the defects in adhesive bonded joints of the piezoelectric sensors by infrared thermographic nondestructive testing

NASA Astrophysics Data System (ADS)

Vinod, P. N.; Joseph, Sherin; John, Reji

2017-04-01

In this paper, efficacy of pulsed thermography technique has been explored for the first time for the detection and quantification of the subsurface defects present in the rubber-encapsulated piezoelectric sensors. Initial experiments were performed on adhesively bonded joints of the rubber/Al or rubber/PZT control samples to find out an optimum acquisition time for the 3-mm rubber encapsulants. Thermographic measurements were performed in the reflection mode and acquired thermal images were analysed and processed images were described in terms of the phase images. The defective regions are identified as delamination of the adhesive joints at the interface of rubber and PZT stacks, and presence of porosity in the encapsulation in the inspected hydrophone. The defect depths of the observed anomalies were calculated empirically from the plots of the peak time of thermal contrast (tmax) maximum and thermal contrast maximum (Cmax) for a particular defect. The estimated defect depths of the prominent porosity observed in the PZT hydrophone are found nearly 1 mm from the surface.

Assessing potential changes of weather-related risk on chestnut productivity

NASA Astrophysics Data System (ADS)

Pereira, Mário; Calheiros, Tomas; Pinto, Joaquim; Caramelo, Liliana

2013-04-01

Weather conditions play an important role during different phases of the vegetative cycle of the chestnut trees and, consequently, several meteorological parameters seem to be associated chestnut productivity (Heiniger and Conedera, 1992, Cesaraccio et al., 2001, Wilczynski and Podalski, 2007, Gomes-Laranjo et al., 2008, Dinis et al., 2011, Pereira et al., 2011). Observed data from European Climate Assessment and simulated data by COSMO-CLM model for the actual (C20) and future (A1B and B1) climate scenarios were used in this study to: (i) assess the model ability to reproduce weather parameters distribution; and, (ii) to assess future changes in the distribution of meteorological parameters which play an important role in the productivity of chestnut for different future periods. Results points to statistical significant changes in the mean and in variance in the future, more prominent in temperature than in precipitation based parameters. Changes in precipitation will be more significant in Northwestern Iberian Peninsula and France in the end of the 21st century for A1B scenario conditions. As expected, more significant changes will be expected to occur during spring and summer, in the Mediterranean areas and in the later period. The number of days with Tmax<28°C will generally decrease in both scenarios, while the changes in the number of days with 24°C

Characterization of starch from tubers of yam bean (Pachyrhizus ahipa).

PubMed

Forsyth, Jane L; Ring, Steve G; Noel, Timothy R; Parker, Roger; Cairns, Paul; Findlay, Kim; Shewry, Peter R

2002-01-16

Detailed studies of the starch present in tubers of six accessions of Pachyrhizus ahipa (ahipa) have been carried out using starches from tubers of P. erosus (Mexican yam bean) and seeds of ahipa and wheat for comparison. Starch accounted for 56-58% of the tuber dry weight with granules occurring in a range of geometric forms and in sizes from below 5 microm to about 35 microm (mean about 10 microm in all accessions except two). The amylose content ranged from 11.6 to 16.8% compared with 16.9% in P. erosus tubers and over 23% in the seed starches. X- ray diffraction analysis showed A-type or C(A)-type diffraction patterns. The chain-length distribution of the amylopectin after enzyme debranching showed a peak at DP11 similar to that of wheat starch, but had a less marked shoulder at DP 21-22 and contained a higher proportion of longer chains. Differential scanning calorimitry showed an endothermic peak corresponding to gelatinization with T(max) ranging from 59 to 63 degrees C, which was similar to the T(max) of wheat (about 64 degrees C). The composition of the ahipa starch may mean that it is suitable for food applications that require low amylose content and low retrogradation after processing.

Magnetic Active Agent Release System (MAARS): evaluation of a new way for a reproducible, externally controlled drug release into the small intestine.

PubMed

Dietzel, Christian T; Richert, Hendryk; Abert, Sandra; Merkel, Ute; Hippius, Marion; Stallmach, Andreas

2012-08-10

Human absorption studies are used to test new drug candidates for their bioavailability in different regions of the gastrointestinal tract. In order to replace invasive techniques (e.g. oral or rectal intubation) a variety of externally controlled capsule-based drug release systems has been developed. Most of these use ionizing radiation, internal batteries, heating elements or even chemicals for the localization and disintegration process of the capsule. This embodies potential harms for volunteers and patients. We report about a novel technique called "Magnetic Active Agent Release System" (MAARS), which uses purely magnetic effects for this purpose. In our trial thirteen healthy volunteers underwent a complete monitoring and release procedure of 250 mg acetylsalicylic acid (ASA) targeting the flexura duodenojejunalis and the mid-part of the jejunum. During all experiments MAARS initiated a sufficient drug release and was well tolerated. Beside this we also could show that the absorption of ASA is about two times faster in the more proximal region of the flexura duodenojejunalis with a tmax of 47±13 min compared to the more distal jejunum with tmax values of 100±10 min (p=0.031). Copyright © 2012 Elsevier B.V. All rights reserved.

Pharmacokinetic profiles of repaglinide in elderly subjects with type 2 diabetes.

PubMed

Hatorp, V; Huang, W C; Strange, P

1999-04-01

Pharmacokinetic profiles of single- and multiple-dose regimens of repaglinide were evaluated in 12 elderly subjects with type 2 diabetes. On day 1, following a 10-hour fast, subjects received a single 2-mg dose of repaglinide. Starting on day 2 and continuing for 7 days, each subject received a 2-mg dose of repaglinide 15 minutes before each of the three main meals. On day 9, subjects received a single 2-mg dose of repaglinide. Pharmacokinetic profiles, including area under the curve (AUC), log(AUC), maximal concentration (Cmax), log(Cmax), time to maximal concentration (Tmax), and half-life (T(1/2)), were determined at completion of the single- and multiple-dose regimens (days 1 and 9, respectively). Trough repaglinide values were collected on days 2 through 7. The mean log(AUC) values after multiple dosing were significantly higher than the values obtained after a single dose. The mean values for log(Cmax), and Tmax were comparable after each dosing regimen. The T(1/2) of repaglinide after multiple dosing was 1.7 hours. The trough values for repaglinide were low. No hypoglycemic events were reported. The pharmacokinetic profiles of repaglinide after single- and multiple-dose regimens were similar, and repaglinide was well tolerated by elderly subjects with type 2 diabetes.

Using apatite fission track thermochronology to document the deformation sequence in an exhumed foreland basin: an example from the southern Pyrenees.

NASA Astrophysics Data System (ADS)

Meresse, F.; Labaume, P.; Jolivet, M.; Teixell, A.

2009-04-01

Université Montpellier 2, INSU-CNRS, Laboratoire Géosciences Montpellier, cc060, 34095 Montpellier Cedex 5, France florian.meresse@gm.univ-montp2.fr The study of foreland basins provides important constraints on the evolution of orogenic wedges. In particular, the study of tectonics-sedimentation relationships is essential to date the tectonic activity. However, processes linked to wedge growth are not always completely recorded by the tecto-sedimentary markers, and thermochronological study of the basin-fill can provide further insights. In this work, we have combined apatite fission track analysis (apatite FTA) with structural analysis to precise the timing of the deformation sequence and to characterise the coupling between thrust activity, burial and denudation in the south-Pyrenean foreland basin, a proximal foredeep of the Pyrenees that has been incorporated in the Pyrenean thrust wedge. We have focused the study on a NNE-SSW cross-section of the south-vergent thrust system from the southern flank of the Axial Zone to the South-Pyrenean Frontal Thrust (SPFT), in the west-central part of the belt. This section provides a complete transverse of the South-Pyrenean Zone, here corresponding to the Ainsa and Jaca basins. Apatite FTA provides important new constraints on the south-Pyrenean foreland basin evolution: (i) Data show the southward decrease of the fission track reset level, from a total reset (indicating heating at Tmax>110°C) in the Paleozoic of the Axial Zone, to a partial reset (110°C>Tmax>60°C) in the lower-middle Eocene Hecho Group turbidites in the northern part of the Jaca basin, and to the absence of reset (Tmax<60°C) in the middle Eocene-Oligocene continental sediments of the southern part of the Jaca basin. This indicates a decreasing amount of denudation going southwards, from more than 4.5 km in the north to less than 2.5 km in the south if we assume an average geothermal gradient around 25°/km. The structural setting of the Jaca basin attests that the burial of sediments was mainly due to sedimentary accumulation. (ii) Results in the Hecho Group turbidites bring evidence of exhumation around 18 Ma on the Oturia thrust in the middle of the Jaca basin, an age that is younger than the Middle Eocene to Aquitanian deformation registered by tecto-sedimentary relationships in the southernmost part of the basin (Guarga syncline and SPFT). These tectonic movements may be related to the exhumation, at the same time, of the southern flank of the Axial Zone by out-of-sequence thrusting on the Bielsa basement thrust (Jolivet et al., 2007*). Therefore, low-temperature thermochronology reveals an out-of-sequence episode of deformation in the interior of the south-Pyrenean thrust wedge that had remained unknown due to the lack of related sedimentary record. This late tectonic activity is younger than the generally admitted Aquitanian age for the end of the Pyrenean compression, and would be linked to an ultimate internal thickening stage in the orogenic wedge (Meresse et al., this volume). (*Tectonics, 2007, vol. 26, doi: 10.1029/2006TC002080)

Determination of Coefficient of Thermal Expansion (CTE) of 20MPa Mass Concrete Using Granite Aggregate

NASA Astrophysics Data System (ADS)

Chee Siang, GO

2017-07-01

Experimental test was carried out to determine the coefficient of thermal expansion (CTE) value of 20MPa mass concrete using granite aggregate. The CTE value was established using procedure proposed by Kada et al. 2002 in determining the magnitude of early-ages CTE through laboratory test which is a rather accurate way by eliminating any possible superimposed effect of others early-age thermal deformation shrinkages such as autogenous, carbonation, plastic and drying shrinkage. This was done by submitting granite concrete block samples instrumented with ST4 vibrating wire extensometers to thermal shocks. The response of the concrete samples to this shock results in a nearly instantaneous deformation, which are measured by the sensor. These deformations, as well as the temperature signal, are used to calculate the CTE. By repeating heat cycles, the variation in the early-ages of concrete CTE over time was monitored and assessed for a period of upto 7 days. The developed CTE value facilitating the verification and validation of actual maximum permissible critical temperature differential limit (rather than arbitrarily follow published value) of cracking potential. For thick sections, internal restraint is dominant and this is governed by differentials mainly. Of the required physical properties for thermal modelling, CTE is of paramount importance that with given appropriate internal restraint factor the condition of cracking due to internal restraint is governs by equation, ΔTmax= 3.663ɛctu / αc. Thus, it can be appreciated that an increase in CTE will lower the maximum allowable differential for cracking avoidance in mass concrete while an increase of tensile strain capacity will increase the maximum allowable temperature differential.

Coronal O VI emission observed with UVCS/SOHO during solar flares: Comparison with soft X-ray observations

NASA Astrophysics Data System (ADS)

Mancuso, S.; Giordano, S.; Raymond, J. C.

2016-06-01

In this work, we derive the O VI 1032 Å luminosity profiles of 58 flares, during their impulsive phase, based on off-limb measurements by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the SOlar and Heliospheric Observatory (SOHO). The O VI luminosities from the transition region plasma (here defined as the region with temperatures 5.0 ≤ log T (K) ≤ 6.0) were inferred from the analysis of the resonantly scattered radiation of the O VI coronal ions. The temperature of maximum ionization for O VI is log Tmax (K) = 5.47. By comparison with simultaneous soft X-ray measurements, we investigate the likely source (chromospheric evaporation, footpoint emission, or heated prominence ejecta) for the transition region emission observed during the impulsive phase. In our study, we find evidence of the main characteristics predicted by the evaporation scenario. Specifically, most O VI flares precede the X-ray peaks typically by several minutes with a mean of 3.2 ± 0.1 min, and clear correlations are found between the soft X-ray and transition region luminosities following power laws with indices ~ 0.7 ± 0.3. Overall, the results are consistent with transition region emission originating from chromospheric evaporation; the thermal X-ray emission peaks after the emission from the evaporation flow as the loops fill with hot plasma. Finally, we were able to infer flow speeds in the range ~20-100 km s-1 for one-third of the events, 14 of which showed speeds between 60 and 80 km s-1. These values are compatible with those found through direct spectroscopic observations at transition region temperatures by the EUV Imaging Spectrometer (EIS) on board Hinode.

Estimation of Surface Air Temperature from MODIS 1km Resolution Land Surface Temperature Over Northern China

NASA Technical Reports Server (NTRS)

Shen, Suhung; Leptoukh, Gregory G.; Gerasimov, Irina

2010-01-01

Surface air temperature is a critical variable to describe the energy and water cycle of the Earth-atmosphere system and is a key input element for hydrology and land surface models. It is a very important variable in agricultural applications and climate change studies. This is a preliminary study to examine statistical relationships between ground meteorological station measured surface daily maximum/minimum air temperature and satellite remotely sensed land surface temperature from MODIS over the dry and semiarid regions of northern China. Studies were conducted for both MODIS-Terra and MODIS-Aqua by using year 2009 data. Results indicate that the relationships between surface air temperature and remotely sensed land surface temperature are statistically significant. The relationships between the maximum air temperature and daytime land surface temperature depends significantly on land surface types and vegetation index, but the minimum air temperature and nighttime land surface temperature has little dependence on the surface conditions. Based on linear regression relationship between surface air temperature and MODIS land surface temperature, surface maximum and minimum air temperatures are estimated from 1km MODIS land surface temperature under clear sky conditions. The statistical errors (sigma) of the estimated daily maximum (minimum) air temperature is about 3.8 C(3.7 C).

Treatment of cyanide wastewater by bulk liquid membrane using tricaprylamine as a carrier.

PubMed

Li, Guoping; Xue, Juanqin; Liu, Nina; Yu, Lihua

2016-01-01

The transport of cyanide from wastewater through a bulk liquid membrane (BLM) containing tricaprylamine (TOA) as a carrier was studied. The effect of cyanide concentration in the feed solution, TOA concentration in the organic phase, the stirring speed, NaOH concentration in the stripping solution and temperature on cyanide transport was determined through BLM. Mass transfer of cyanide through BLM was analyzed by following the kinetic laws of two consecutive irreversible first-order reactions, and the kinetic parameters (k(1), k(2), R(m)(max), t(max), J(a)(max), J(d)(max)) were also calculated. Apparently, increase in membrane entrance (k(1)) and exit rate (k(2)) constants was accompanied by a rise in temperature. The values of activation energies were obtained as 35.6 kJ/mol and 18.2 kJ/mol for removal and recovery, respectively. These values showed that both removal and recovery steps in cyanide transport is controlled by the rate of the chemical complexation reaction. The optimal reaction conditions were determined by BLM using trioctylamine as the carrier: feed phase: pH 4, carrier TOA possession ratio in organic phase: 2% (V/V), stripping phase concentration of NaOH: 1% (W/V), reaction time: 60 min, stirring speed: 250 r/min. Under the above conditions, the removal rate was up to 92.96%. The experiments demonstrated that TOA was a good carrier for cyanide transport through BLM in this study.

Physicochemical characterization and in vivo evaluation of poloxamer-based solid suppository containing diclofenac sodium in rats.

PubMed

Yong, Chul Soon; Oh, Yu-Kyoung; Kim, Yong-Il; Kim, Jong Oh; Yoo, Bong-Kyu; Rhee, Jong-Dal; Lee, Kang Choon; Kim, Dae-Duk; Park, Young-Joon; Kim, Chong-Kook; Choi, Han-Gon

2005-09-14

To develop a poloxamer-based solid suppository with poloxamer mixtures, the melting point of various formulations composed of poloxamer 124 (P 124) and poloxamer 188 (P 188) were investigated. The dissolution and pharmacokinetic study of diclofenac sodium delivered by the poloxamer-based suppository were performed. Furthermore, the identification test in the rectum and morphology test of rectal tissues were carried out after its rectal administration in rats. The poloxamer mixtures composed of P 124 and P 188 were homogeneous phases. Very small amounts of P 188 affected the melting point of poloxamer mixtures. In particular, the poloxamer mixture [P 124/P 188 (97/3%)] with the melting point of about 32 degrees C was a solid form at room temperature and instantly melted at physiological temperature. Very small amounts of P 188 hardly affected the dissolution rates of diclofenac sodium from the suppository. Dissolution mechanism analysis showed the dissolution of diclofenac sodium was proportional to the time. The poloxamer-based suppository gave significantly higher initial plasma concentrations and faster T(max) of diclofenac sodium than did conventional PEG-based suppository, indicating that the drug from poloxamer-based suppository could be absorbed faster than that from PEG-based one in rats. It retained in the rectum for at least 4 h and could not irritate or damage the rectal tissues of rats. Thus, the poloxamer-based solid suppository with P 124 and P 188 was a mucoadhesive, safe and effective rectal dosage form for diclofenac sodium.

Initial Design Study of Existing Flight Control System of RPH and Feasibility Study of Implementing HHC on the SH-60B

DTIC Science & Technology

1990-09-01

35 C. HYDRAULICS ............................................. 39 iv VII. CONCLUSIONS AND RECOMMENDATIONS...requirement can be calculated. The maximum RMS torque required was obtained using the following equation: TMAX = t MAr T ZSm (15) 14 IV. RESULTS A...with the addition to added weight on the pitch arm/link 35 assemblies all related components would have to be strengthened to take the centrifugal loads

Investigation of temperature and its indices under climate change scenarios over different regions of Rajasthan state in India

NASA Astrophysics Data System (ADS)

Sharma, Aditya; Sharma, Devesh; Panda, S. K.; Dubey, Swatantra Kumar; Pradhan, Rajani K.

2018-02-01

The ongoing increases in concentrations of atmospheric greenhouse gas will most likely affect global climate for the rest of this century. Global warming brings a huge provocation to society and human beings. Single extreme events and increased climate variability have a greater impact than long-term changes in the mean of climatic variables. This study analyzed the temperature projections for Rajasthan state, India using data obtain from two General Circulation Models (GFCM21 and HadCM3) for three Intergovernmental Panel on Climate Change (IPCC) Special Range of Emission Scenarios (SRES) A1B, A2, and B1. A 30 years of maximum (Tmax) and minimum (Tmin) temperature for the period 1976-2005 has been obtained from India Meteorological Department (IMD) and by using LARS-WG5 to generate the long-term weather series for three different periods i.e. 2011-2040 (2025s), 2041-2070 (2055s), and 2071-2100 (2085s). Further to determine the changes in extreme temperature events, the data for the baseline period and the future periods was represented by eight extreme temperature indices. Results illustrate that an increase in minimum and the maximum temperature are observed in all the three future periods. The average mean temperature for base period and three future periods over four regions of Rajasthan was observed highest in region 3 which shows an incessantly increased in mean temperature about 2.6 °C i.e. north-east and north-west part of Rajasthan. Two GCMs depicts that the incessant temperatures may be increase in the future and future maximum temperature in all the seasons varies from 2.43 °C to 4.27 °C in the direction from south to north of Rajasthan during 2071-2100. While for minimum temperature, the range of temperature changes varies from 0.23 °C to 1.42 °C from south-east to north-west of Rajasthan during 2011-2040. In the temperature indices, the number of tropical nights (TR20), warmest day (TX90p), warmest night (TN90p) and summer days (SU25) is expected to increase during all three future periods. The maximum changes was found in region 2 (39.4 days) and region 1 (38.8 days) during the 2071-2100 periods, followed by 2041-2070 and 2011-2040. In all the four regions, the annual occurrence of Cold Spells Duration Indicator (CSDI) decreased and Warm Spells Duration Indicator (WSDI) increased for all three future periods.

Climate change impacts on rainfall and temperature in sugarcane growing Upper Gangetic Plains of India

NASA Astrophysics Data System (ADS)

Verma, Ram Ratan; Srivastava, Tapendra Kumar; Singh, Pushpa

2018-01-01

Assessment of variability in climate extremes is crucial for managing their aftermath on crops. Sugarcane (Saccharum officinarum L.), a major C4 crop, dominates the Upper Gangetic Plain (UGP) in India and is vulnerable to both direct and indirect effects of changes in temperature and rainfall. The present study was taken up to assess the weekly, monthly, seasonal, and annual trends of rainfall and temperature variability during the period 1956-2015 (60 years) for envisaging the probabilities of different levels of rainfall suitable for sugarcane in UGP in the present climate scenario. The analysis revealed that 87% of total annual rainfall was received during southwest monsoon months (June-September) while post-monsoon (October to February) and pre-monsoon months (March-May) accounted for only 9.4 and 3.6%, respectively. There was a decline in both monthly and annual normal rainfall during the period 1986-2015 as compared to 1956-1985, and an annual rainfall deficiency of 205.3 mm was recorded. Maximum monthly normal rainfall deficiencies of 52.8, 84.2, and 54.0 mm were recorded during the months of July, August, and September, respectively, while a minimum rainfall deficiency of 2.2 mm was observed in November. There was a decline by 196.3 mm in seasonal normal rainfall during June-September (kharif). The initial probability of a week going dry was higher (> 70%) from the 1st to the 25th week; however, standard meteorological weeks (SMW) 26 to 37 had more than 50% probability of going wet. The normal annual maximum temperature (Tmax) decreased by 0.4 °C while normal annual minimum temperatures (Tmin) increased by 0.21 °C. Analysis showed that there was an increase in frequency of drought from 1986 onwards in the zone and a monsoon rainfall deficit by about 21.25% during June-September which coincided with tillering and grand growth stage of sugarcane. The imposed drought during the growth and elongation phase is emerging as a major constraint in realizing high cane productivity in the zone. Strategies for mitigating the negative impacts of rainfall and temperature variability on sugarcane productivity through improvement in existing adaptation strategies are proposed.

Short initial length quench on CICC of ITER TF coils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nicollet, S.; Ciazynski, D.; Duchateau, J.-L.

Previous quench studies performed for the International Thermonuclear Experimental Reactor (ITER) Toroidal Field (TF) Coils have led to identify two extreme families of quench: first 'severe' quenches over long initial lengths in high magnetic field, and second smooth quenches over short initial lengths in low field region. Detailed analyses and results on smooth quench propagation and detectability on one TF Cable In Conduit Conductor (CICC) with a lower propagation velocity are presented here. The influence of the initial quench energy is shown and results of computations with either a Fast Discharge (FD) of the magnet or without (failure of themore » voltage quench detection system) are reported. The influence of the central spiral of the conductor on the propagation velocity is also detailed. In the cases of a regularly triggered FD, the hot spot temperature criterion of 150 K (with helium and jacket) is fulfilled for an initial quench length of 1 m, whereas this criterion is exceed (Tmax ≈ 200 K) for an extremely short length of 5 cm. These analyses were carried out using both the Supermagnet(trade mark, serif) and Venecia codes and the comparisons of the results are also discussed.« less

Model and Scenario Variations in Predicted Number of Generations of Spodoptera litura Fab. on Peanut during Future Climate Change Scenario

PubMed Central

Srinivasa Rao, Mathukumalli; Swathi, Pettem; Rama Rao, Chitiprolu Anantha; Rao, K. V.; Raju, B. M. K.; Srinivas, Karlapudi; Manimanjari, Dammu; Maheswari, Mandapaka

2015-01-01

The present study features the estimation of number of generations of tobacco caterpillar, Spodoptera litura. Fab. on peanut crop at six locations in India using MarkSim, which provides General Circulation Model (GCM) of future data on daily maximum (T.max), minimum (T.min) air temperatures from six models viz., BCCR-BCM2.0, CNRM-CM3, CSIRO-Mk3.5, ECHams5, INCM-CM3.0 and MIROC3.2 along with an ensemble of the six from three emission scenarios (A2, A1B and B1). This data was used to predict the future pest scenarios following the growing degree days approach in four different climate periods viz., Baseline-1975, Near future (NF) -2020, Distant future (DF)-2050 and Very Distant future (VDF)—2080. It is predicted that more generations would occur during the three future climate periods with significant variation among scenarios and models. Among the seven models, 1–2 additional generations were predicted during DF and VDF due to higher future temperatures in CNRM-CM3, ECHams5 & CSIRO-Mk3.5 models. The temperature projections of these models indicated that the generation time would decrease by 18–22% over baseline. Analysis of variance (ANOVA) was used to partition the variation in the predicted number of generations and generation time of S. litura on peanut during crop season. Geographical location explained 34% of the total variation in number of generations, followed by time period (26%), model (1.74%) and scenario (0.74%). The remaining 14% of the variation was explained by interactions. Increased number of generations and reduction of generation time across the six peanut growing locations of India suggest that the incidence of S. litura may increase due to projected increase in temperatures in future climate change periods. PMID:25671564

A Laboratory Study on the Modeling of Temperature-Dependent Development and Antioxidant System of Chilo suppressalis (Lepidoptera: Crambidae)

PubMed Central

Shamakhi, Leila; Zibaee, Arash; Karimi-Malati, Azadeh; Hoda, Hassan

2018-01-01

Abstract The developmental rates of Chilo suppressalis (Walker; Lepidoptera: Crambidae) were investigated at different constant temperatures of 11, 18, 22, 24, 26, 30, 32, 34, and 36°C to find out temperature thresholds, thermal requirements and larval antioxidant responses. The time to complete immature stages separately reduced by raising the rearing temperature except for eggs which showed no significant differences at 30–34°C. Data analysis by traditional and Ikemoto–Takai linear models determined Tmin of 10.0 and 9.92°C as well as thermal constants of 840.34 and 848.0 DD for the overall immature stages. The models including Analytis, Briere-2, Lactin-2, and Sharpe–Schoolfield–Ikemoto (SSI) calculated Tmin values of 9.15, 9.57, 10.0, and 11.37°C for overall immature stages while Tfast was found to be 33.8, 33.3, 33.7, and 33.0°C, respectively. Tmax was calculated as 35.12, 34.66, 34.56, 36.84, 34.11, and 35.15°C for Analytis, Briere-2, Lactin-2, SSI, Logan-6, and Logan-10. Topt using SSI was calculated as 24.42°C for total developmental time. The larvae exposure to 34°C in the short-term period demonstrated the highest activities of catalase, peroxidase, and superoxide dismutase compared to control (24°C). Activities of ascorbate peroxidase and glucose-6-phosphate hydrogenase also increased at 34°C in the short-term period for all preparations. The larvae exposed to 34°C in short-term period showed the highest amounts of Malondialdehyde and oxidized and reduced thiols (RSSR/RSH) ratio compared to control. These results may be useful to explain potentially ecological performance of C. suppressalis as the major pest of rice in Iran. PMID:29718498

The IRM at 25: A Quarter Century of Community-Based Research and Education at the Institute for Rock Magnetism

NASA Astrophysics Data System (ADS)

Moskowitz, B. M.

2015-12-01

A 1986 meeting on the future of rock magnetism proposed an idea for a center where researchers in rock magnetism, other earth science disciplines, and allied fields in the physical sciences could share ideas and have access to advanced instrumentation in magnetism. The idea became reality in 1990, when the Institute for Rock Magnetism (IRM) was established as a shared resource for the GP and broader research communities, providing instruments to study the magnetism of rocks, sediment, biological materials and synthetic analogs. This is accomplished with a suite of instruments that measures magnetization from 2-1000 K, in DC fields up to 5 T and AC fields up to 10 kHz. These are complemented by Mössbauer spectrometers (4.2-300K, 0-6.5T), a high-temperature magnetic force microscope (Tmax~ 673 K), and a low-temperature probe (20-300 K) for vector remanence measurements. A unique aspect of the IRM was that it allowed for routine measurements below 300 K and provided new ways of "seeing" magnetism. This has enabled researchers to study magnetic behavior through magnetic ordering temperatures, crystal phase transitions, and blocking temperatures, providing new insights into mineral magnetism as well as developing new methods to interpret the magnetism of natural materials. The main access to the IRM is the Visiting Fellowship (VF) program, where 379 have been awarded representing 157 institutions from the US and 30 countries. Nearly 50% of VFs have gone to students. The total output of visiting and in-house researches have produced about 800 publications to date. The IRM also provides education and outreach activities including: (1) The IRM Quarterly with over 600 subscribers; (2) The Biennial Santa Fe meetings on the current state and future trends in magnetic research; and (3) The Biennial Summer Schools for Rock Magnetism offering graduate students in the geosciences with instruction in rock magnetism theory and hands-on lab training.

Quench degradation limit of multifilamentary AgBi 2Sr 2CaCu 2O x round wires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Liyang; Li, Pei; Shen, Tengming

Understanding safe operating limits of composite superconducting wires is important for the design of superconducting magnets. Here we report measurements of quench-induced critical current density Jc degradation in commercial Ag/Bi 2Sr 2CaCu 2O x (Bi-2212) round wires using heater-induced quenches at 4.2 K in self magnetic field that reveal a general degradation behavior. J c degradation strongly depends on the local hot spot temperature T max, and is nearly independent of operating current, the temperature gradient along the conductor dT max/dx, and the temperature rising rate dT max/dt. Both J c and n value (where n is an index ofmore » the sharpness of the superconductor-to-normal transition) exhibit small but irreversible degradation when T max exceeds 400-450 K, and large degradation occurs when Tmax exceeds 550 K. This behavior was consistently found for a series of Bi-2212 wires with widely variable wire architectures and porosity levels in the Bi-2212 filaments, including a wire processed using a standard partial melt processing and in which Bi-2212 filaments are porous, an overpressure processed wire in which Bi-2212 filaments are nearly porosity-free and that has a J c(4.2 K, self field) exceeding 8000 A/mm 2, and a wire that has nearly no filament to filament bridges after reaction. Microstructural observations of degraded wires reveal cracks in the Bi-2212 filaments perpendicular to the wire axis, indicating that the quench-induced I c degradation is primarily driven by strain. These results further suggest that the quench degradation temperature limit depends on the strain state of Bi-2212 filaments and this dependence shall be carefully considered when engineering a high-field Bi-2212 magnet.« less

Quench degradation limit of multifilamentary AgBi 2Sr 2CaCu 2O x round wires

DOE PAGES

Ye, Liyang; Li, Pei; Shen, Tengming; ...

2016-02-02

Understanding safe operating limits of composite superconducting wires is important for the design of superconducting magnets. Here we report measurements of quench-induced critical current density Jc degradation in commercial Ag/Bi 2Sr 2CaCu 2O x (Bi-2212) round wires using heater-induced quenches at 4.2 K in self magnetic field that reveal a general degradation behavior. J c degradation strongly depends on the local hot spot temperature T max, and is nearly independent of operating current, the temperature gradient along the conductor dT max/dx, and the temperature rising rate dT max/dt. Both J c and n value (where n is an index ofmore » the sharpness of the superconductor-to-normal transition) exhibit small but irreversible degradation when T max exceeds 400-450 K, and large degradation occurs when Tmax exceeds 550 K. This behavior was consistently found for a series of Bi-2212 wires with widely variable wire architectures and porosity levels in the Bi-2212 filaments, including a wire processed using a standard partial melt processing and in which Bi-2212 filaments are porous, an overpressure processed wire in which Bi-2212 filaments are nearly porosity-free and that has a J c(4.2 K, self field) exceeding 8000 A/mm 2, and a wire that has nearly no filament to filament bridges after reaction. Microstructural observations of degraded wires reveal cracks in the Bi-2212 filaments perpendicular to the wire axis, indicating that the quench-induced I c degradation is primarily driven by strain. These results further suggest that the quench degradation temperature limit depends on the strain state of Bi-2212 filaments and this dependence shall be carefully considered when engineering a high-field Bi-2212 magnet.« less

High-intensity interval training and β-hydroxy-β-methylbutyric free acid improves aerobic power and metabolic thresholds.

PubMed

Robinson, Edward H; Stout, Jeffrey R; Miramonti, Amelia A; Fukuda, David H; Wang, Ran; Townsend, Jeremy R; Mangine, Gerald T; Fragala, Maren S; Hoffman, Jay R

2014-01-01

Previous research combining Calcium β-hydroxy-β-methylbutyrate (CaHMB) and running high-intensity interval training (HIIT) have shown positive effects on aerobic performance measures. The purpose of this study was to examine the effect of β-hydroxy-β-methylbutyric free acid (HMBFA) and cycle ergometry HIIT on maximal oxygen consumption (VO2peak), ventilatory threshold (VT), respiratory compensation point (RCP) and time to exhaustion (Tmax) in college-aged men and women. Thirty-four healthy men and women (Age: 22.7 ± 3.1 yrs ; VO2peak: 39.3 ± 5.0 ml · kg(-1) · min(-1)) volunteered to participate in this double-blind, placebo-controlled design study. All participants completed a series of tests prior to and following treatment. A peak oxygen consumption test was performed on a cycle ergometer to assess VO2peak, Tmax, VT, and RCP. Twenty-six participants were randomly assigned into either a placebo (PLA-HIIT) or 3 g per day of HMBFA (BetaTor™) (HMBFA-HIIT) group. Eight participants served as controls (CTL). Participants in the HIIT groups completed 12 HIIT (80-120% maximal workload) exercise sessions consisting of 5-6 bouts of a 2:1 minute cycling work to rest ratio protocol over a four-week period. Body composition was measured with dual energy x-ray absorptiometry (DEXA). Outcomes were assessed by ANCOVA with posttest means adjusted for pretest differences. The HMBFA-HIIT intervention showed significant (p < 0.05) gains in VO2peak, and VT, versus the CTL and PLA-HIIT group. Both PLA-HIIT and HMBFA-HIIT treatment groups demonstrated significant (p < 0.05) improvement over CTL for Tmax, and RCP with no significant difference between the treatment groups. There were no significant differences observed for any measures of body composition. An independent-samples t-test confirmed that there were no significant differences between the training volumes for the PLA-HIIT and HMBFA-HIIT groups. Our findings support the use of HIIT in combination with HMBFA to improve aerobic fitness in college age men and women. These data suggest that the addition of HMBFA supplementation may result in greater changes in VO2peak and VT than HIIT alone. The study was registered on ClinicalTrials.gov (ID NCT01941368).

Complete Freund's adjuvant induces experimental autoimmune myocarditis by enhancing IL-6 production during initiation of the immune response.

PubMed

Fontes, Jillian A; Barin, Jobert G; Talor, Monica V; Stickel, Natalie; Schaub, Julie; Rose, Noel R; Čiháková, Daniela

2017-06-01

Complete Freund's Adjuvant (CFA) emulsified with an antigen is a widely used method to induce autoimmune disease in animal models, yet the contribution of CFA to the immune response is not well understood. We compared the effectiveness of CFA with Incomplete Freund's Adjuvant (IFA) or TiterMax Gold Adjuvant (TMax) in experimental autoimmune myocarditis (EAM) in male mice. EAM was induced in A/J, BALB/c, and IL6KO BALB/c male mice by injection of the myocarditogenic peptide in CFA, IFA, or TMax on days 0 and 7. EAM severity was analyzed by histology on day 21. In addition, specific flow cytometry outcomes were evaluated on day 21. Only mice immunized with CFA and myocarditogenic peptide on both days 0 and 7 developed substantial myocarditis as measured by histology. We observed a significantly increased level of IL6 in the spleen 3 days after CFA immunization. In the spleen and heart on day 21, there was an expansion of myeloid cells in CFA-immunized mice, as compared to IFA or TMax-immunized animals. Recombinant IL-6 at the time of IFA immunization partially restored susceptibility of the mice to EAM. We also treated EAM-resistant IL-6 knockout mice with recombinant IL-6 around the time of the first immunization, on days -1 to 2, completely restoring disease susceptibility, showing that the requirement for IL-6 coincides with primary immunization. Examining APC populations in the lymph node draining the immunization site evidenced the contribution of IL-6 to the CFA-dependence of EAM was through controlling local dendritic cell (DC) trafficking. CFA used with myocarditogenic peptide twice is required to induce EAM in both A/J and Balb/c mice. Although IFA and TiterMax induce antibody responses, only CFA preferentially induced autoantigen-specific responses. CFA expands monocytes in the heart and in the spleen. IL-6 signaling is required during short window around primary immunization to induce EAM. In addition, IL-6 deficient mice resistance to EAM could be reversed by injecting IL-6 around first immunization. IL-6 expands dendritic cell and monocytic populations and ultimately leads to a robust T-cell driven immune response in CFA immunized mice. © 2017 The Authors. Immunity, Inflammation and Disease Published by John Wiley & Sons Ltd.

Comparative single-dose pharmacokinetics of clonazepam following intravenous, intramuscular and oral administration to healthy volunteers.

PubMed

Crevoisier, C; Delisle, M C; Joseph, I; Foletti, G

2003-01-01

The objective was to assess the single-dose pharmacokinetics of clonazepam following i.m., p.o. and i.v. administration. In an open-label, three-way crossover study, 12 healthy volunteers were randomized to receive a single dose of 2 mg clonazepam either by the i.m., p.o. or i.v. route. Serial blood samples were collected up to 120 h after drug administration. Plasma concentrations of clonazepam were determined by electron-capture gas-liquid chromatography. The absorption rates of clonazepam after i.m. and p.o. administration of clonazepam were significantly different from each other, as reflected by the respective mean values of maximum plasma concentration (C(max) 11.0 vs. 14.9 ng.ml(-1)) and time to reach maximum concentration (t(max) 3.1 vs. 1.7 h). Secondary plasma peaks of clonazepam were observed in 9 volunteers after i.m. injection (C(max) 9.9 ng.ml(-1); t(max) 10.4 h). A comparison of the area under the plasma concentration-time curves (AUC) shows that the i.m. route is equivalent to the oral route (AUC(0- infinity ) 620 vs. 561 ng.h.ml(-1)). Clonazepam was almost completely absorbed after i.m. and p.o. administration, as shown by the mean absolute bioavailability of 93 and 90%, respectively. No significant differences existed between the elimination half-lives (i.v. 38.0 h; i.m. 43.6 h; p.o. 39.0 h). The average clearance and volume of distribution (V(Z)) were 55 ml.min(-1) and 180 liters, respectively. In conclusion, the observed differences in C(max) and t(max) after i.m. and p.o. administration were consistent with a slower absorption rate of clonazepam after i.m. injection. The systemic exposure to clonazepam was not affected by the route of extravascular administration. Statistical evaluation of these kinetic data showed differences in the absorption rate, so that clonazepam given by the i.m. route is not bioequivalent to the oral route. On the basis of the results of this study, we would recommend the same i.m. and p.o. dose in epileptic patients, but therapeutic response would be expected to be less predictable and to occur later in the case of i.m. administration. Copyright 2003 S. Karger AG, Basel

Evaluation of Surface Fatigue Strength Based on Surface Temperature

NASA Astrophysics Data System (ADS)

Deng, Gang; Nakanishi, Tsutomu

Surface temperature is considered to be an integrated index that is dependent on not only the load and the dimensions at the contact point but also the sliding velocity, rolling velocity, surface roughness, and lubrication conditions. Therefore, the surface durability of rollers and gears can be evaluated more exactly and simply by the use of surface temperature rather than Hertzian stress. In this research, surface temperatures of rollers under different rolling and sliding conditions are measured using a thermocouple. The effects of load P, mean velocity Vm and sliding velocity Vs on surface temperature are clarified. An experimental formula, which expresses the linear relationship between surface temperature and the P0.86Vs1.31Vm-0.83 value, is used to determine surface temperature. By comparing calculated and measured temperature on the tooth surface of a gear, this formula is confirmed to be applicable for gear tooth surface temperature calculation.

Evaluation and monitoring of UVR in Shield Metal ARC Welding processing.

PubMed

Peng, Chiung-yu; Liu, Hung-hsin; Chang, Cheng-ping; Shieh, Jeng-yueh; Lan, Cheng-hang

2007-08-01

This study established a comprehensive approach to monitoring UVR magnitude from Shield Metal Arc Welding (SMAW) processing and quantified the effective exposure based on measured data. The irradiances from welding UVR were calculated with biological effective parameter (Slambda) for human exposure assessment. The spectral weighting function for UVR measurement and evaluation followed the American Conference of Governmental Industrial Hygienists (ACGIH) guidelines. Arc welding processing scatters bright light with UVR emission over the full UV spectrum (UVA, UVB, and UVC). The worst case of effective irradiance from a 50 cm distance arc spot with a 200 A electric current and an electrode E6011 (4 mm) is 311.0 microW cm(-2) and has the maximum allowance time (Tmax) of 9.6 s. Distance is an important factor affecting the irradiance intensity. The worst case of the effective irradiance values from arc welding at 100, 200, and 300 cm distances are 76.2, 16.6, and 12.1 microW cm(-2) with Tmax of 39.4, 180.7, and 247.9 s, respectively. Protective materials (glove and mask) were demonstrated to protect workers from hazardous UVR exposure. From this study, the methodology of UVR monitoring in SMAW processing was developed and established. It is recommended that welders should be fitted with appropriate protective materials for protection from UVR emission hazards.

[Biomechanical research of antegrade intramedullary fixation for the metacarpal fractures].

PubMed

Zhang, Li-shan; Pan, Yong-wei; Tian, Guang-lei; Li, Wen-jun; Xia, Shao-hua; Tao, Jian-feng

2010-04-15

To study the biomechanical characteristics of antegrade intramedullary fixation for metacarpal fractures. From March to May 2008, both the 4th and 5th metacarpals from 25 formalin embalmed cadaver hands had three-point bending test after transverse osteotomy followed by randomly fixation with one of the following three methods: plate and screw, antegrade intramedullary K-wire, crossed K-wire. While, both the 2nd and 3rd metacarpals had torsional loading test after the same management as the 4th and 5th metacarpal had undergone. In the three-point bending test, both the maximum bending moment (M(max)) and bending rigidity (EI) of the antegrade intramedullary K-wire were comparable with those of the plate and screw, and were significantly larger than those of the crossed K-wire. In the torsional loading test, the antegrade intramedullary K-wire had a statistically smaller maximum torque (T(max)) than the plate and screw, and had a comparable T(max) with the crossed K-wire; while, the torsional rigidity (GJ) of the intramedullary K-wire was statistically weaker than that of both the plate and screw and the crossed wire. One single antegrade intramedullary K-wire can provide a satisfactory M(max) and EI for metacarpal fixation and shows relatively weak in the torsional loading test. The injured finger should be well protected to avoid torsional deformity in clinical practice.

Progesterone administration by nasal spray in menopausal women: comparison between two different spray formulations.

PubMed

Cicinelli, E; Savino, F; Cagnazzo, I; Scorcia, P; Galantino, P

1992-12-01

The aim of the study was to compare the bioavailability of progesterone dissolved in almond oil or dimethicone, and administered by nasal spray. Twenty healthy menopausal women were randomly allocated to treatment by four doses of intranasal spray either of a progesterone solution in almond oil, 2 mg/0.1 ml, corresponding to a total dose of approximately 11 mg of progesterone, or a progesterone solution in dimethicone 5 mg/0.1 ml corresponding to a total dose of approximately 28 mg of progesterone. Circulating progesterone levels were calculated at various time intervals following administration. The formulation with almond oil yielded a maximum progesterone concentration (Cmax of 3.75 ng/ml at Tmax = 60 min, and the area under the curve (AUC0-720) value was 1481.6 +/- 343. The formulation with dimethicone yielded a mean Cmax of 1.049 ng/ml at Tmax = 30 min; the AUC0-720 value was 302.06 +/- 37.5. Therefore, bioavailability of progesterone dissolved in almond oil proved to be largely superior compared to the solution in dimethicone. The crucial role of the carrier in the spray formulations is discussed; in addition to ensuring clinical safety, it must have good solubility for progesterone, be fluid enough to enable efficient 'spraying' and also must allow progesterone to be absorbed through the nasal mucosa.

Large cooling differentials and high heat flux capability with p-type Bi2Te3/Sb2Te3 and n-type Bi2Te3/Bi2SexTe3-x Superlattice Thermoelectric Devices

NASA Astrophysics Data System (ADS)

Bulman, Gary; Siivola, Ed; Wiitala, Ryan; Grant, Brian; Pierce, Jonathan; Venkatasubramanian, Rama

2007-03-01

Thin film superlattice (SL) based thermoelectric (TE) devices offer the potential for improved efficiency and high heat flux cooling over conventional bulk materials. Recently, we have demonstrated external cooling of 55K and heat pumping capacity of 128 W/cm^2. These high heat fluxes in thin film devices, while attractive for cooling hot-spots in electronics, also make the device performance sensitive to various thermal resistances in the device structure. We will discuss advances in the cooling performance of Bi2Te3-based SL TE devices and describe a method to extract device material parameters, including thermal resistance, from measurements of their δT-I-V characteristics. These parameters will be compared to values obtained through Hall and Seebeck coefficient measurement on epitaxial materials. Results will be presented for both single couple and multi-couple modules, as well as multi-stage cascaded devices made with these materials. Single stage cooling couples with δTmax of 57.8K (Tc˜242K) and multi-stage modules with δTmax˜92.2K (Tc˜209K) have been measured. G.E. Bulman, E. Siivola, B. Shen and R. Venkatasubramanian, Appl. Phys. Lett. 89, 122117 (2006).

Formulation of itraconazole nanococrystals and evaluation of their bioavailability in dogs.

PubMed

De Smet, Lieselotte; Saerens, Lien; De Beer, Thomas; Carleer, Robert; Adriaensens, Peter; Van Bocxlaer, Jan; Vervaet, Chris; Remon, Jean Paul

2014-05-01

The aim of the study is to increase the bioavailability of itraconazole (ITRA) using nanosized cocrystals prepared via wet milling of ITRA in combination with dicarboxylic acids. Wet milling was used in order to create a nanosuspension of ITRA in combination with dicarboxylic acids. After spray-drying and bead layering, solid state was characterized by MDSC, XRD, Raman and FT-IR. The release profiles and bioavailability of the nanococrystalline suspension, the spray-dried and bead layered formulation were evaluated. A monodisperse nanosuspension (549±51nm) of ITRA was developed using adipic acid and Tween®80. Solid state characterization indicated the formation of nanococrystals by hydrogen bounds between the triazole group of ITRA and the carboxyl group of adipic acid. A bioavailability study was performed in dogs. The faster drug release from the nanocrystal-based formulation was reflected in the in vivo results since Tmax of the formulations was obtained 3h after administration, while Tmax of the reference formulation was observed only 6h after administration. This fast release of ITRA was obtained by a dual concept: manufacturing of nanosized cocrystals of ITRA and adipic acid via wet milling. Formation of stable nanosized cocrystals via this approach seems a good alternative for amorphous systems to increase the solubility and obtain a fast drug release of BCS class II drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

Pharmacodynamics and pharmacokinetics of haloperidol and reduced haloperidol in schizophrenic patients.

PubMed

Chang, W H; Lin, S K; Jann, M W; Lam, Y W; Chen, T Y; Chen, C T; Hu, W H; Yeh, E K

1989-07-01

Twelve male chronic schizophrenic inpatients, neuroleptic-free for at least 4 weeks, were given an oral test dose of 10 mg haloperidol (HAL) and reduced HAL (RHAL) in a random order, with a 2-week interval. Two weeks after the last test dose, the patients were given HAL, 5 mg orally twice daily for 7 days. Blood samples were drawn at baseline and between 0.5 and 24 hr after the test doses, and during HAL treatment as well. Plasma drug concentrations and homovanillic acid (HVA) levels were measured with high-performance liquid chromatography using electrochemical detection. HAL, but not RHAL, produced increments in plasma HVA (pHVA) levels at 24 hr after a test dose. pHVA levels remained higher than baseline during HAL treatment. Detectable interconversion between HAL and RHAL was observed in eight patients. The capacity of the reductive drug-metabolizing enzyme system, however, was greater than that of the oxidative processes. The plasma RHAL:HAL ratios on days 6 and 7 were higher than and positively correlated with those at Tmax after a single dose of HAL and were negatively correlated with the HAL:RHAL ratios at Tmax after a single dose of RHAL. Thus, both reductive and oxidative drug-metabolizing systems probably contribute to individual differences in plasma RHAL:HAL ratios in HAL-treated schizophrenic patients.

Effect of gastric emptying and entero-hepatic circulation on bioequivalence assessment of ranitidine.

PubMed

Chrenova, J; Durisova, M; Mircioiu, C; Dedik, L

2010-01-01

The aim of study was to compare the bioavailability of ranitidine obtained from either Ranitidine (300 mg tablet; LPH® S.C. LaborMed Pharma S.A. Romania: the test formulation) and Zantac® (300 mg tablet; GlaxoSmithKline, Austria: the reference formulation). Twelve, Romanian, healthy volunteers were enrolled in the study. An open-label, two-period, crossover, randomized design was used. Plasma levels of ranitidine were determined using the validated, high-pressure liquid chromatography (HPLC) method. The physiologically motivated time-delayed model was used for the data evaluation and a paired Student's t-test and Schuirmann's two one-sided tests were carried out to compare parameters. Nonmodeling parameters (AUC(t), AUC, C(max), T(max)) were tested by the paired Student's t-test and the 90 confidence intervals of the geometric mean ratios were determined by Schuirmann's tests. Paired Student's t-test showed no significant differences between nonmodeling and modeling parameters. The results of the Schuirmann's tests however indicated significant statistical differences with reference to AUC(t), AUC, C(max), T(max) and other modeling parameters, especially MT(c) and τ(c). Schuirmann's tests revealed significant bioequivalence between ranitidine formulations using the modeling parameters MRT and n. The presented model can be useful as an additional tool to assess drug bioequivalence, by screening for disruptive parameters. Copyright 2010 Prous Science, S.A.U. or its licensors. All rights reserved.

Enhancement of the Oral Bioavailability of Fexofenadine Hydrochloride via Cremophor® El-Based Liquisolid Tablets

PubMed Central

Yehia, Soad Ali; El-Ridi, Mohamed Shafik; Tadros, Mina Ibrahim; El-Sherif, Nolwa Gamal

2015-01-01

Purpose: The current work aimed to develop promising Fexofenadine hydrochloride (FXD) liquisolid tablets able to increase its oral bioavailability and shorten time to reach maximum plasma concentrations (Tmax). Methods: Eighteen liquisolid powders were developed based on 3 variables; (i) vehicle type [Propylene glycol (PG) or Cremophor® EL (CR)], (ii) carrier [Avicel® PH102] to coat [Aerosil® 200] ratio (15, 20, 25) and (iii) FXD concentration in vehicle (30, 35, 40 %, w/w). Pre-compression studies involved identification of physicochemical interactions and FXD crystallinity (FT-IR, DSC, XRD), topographic visualization (SEM) and estimation of flow properties (angle of repose, Carr’s index, Hausner’s ratio). CR-based liquisolid powders were compressed as liquisolid tablets (LST 9 – 18) and evaluated for weight-variation, drug-content, friability-percentage, disintegration-time and drug-release. The pharmacokinetics of LST-18 was evaluated in healthy volunteers relative to Allegra® tablets. Results: Pre-compression studies confirmed FXD dispersion in vehicles, conversion to amorphous form and formation of liquisolid powders. CR-based liquisolid powders showed acceptable-to-good flow properties suitable for compaction. CR-based LSTs had appropriate physicochemical properties and short disintegration times. Release profile of LST-18 showed a complete drug release within 5 min. Conclusion: LST-18 succeeded in increasing oral FXD bioavailability by 62% and reducing Tmax to 2.16 h. PMID:26819931

[Effect of phenformin hydrochloride on pharmacokinetics of puerarin in rats].

PubMed

Deng, Ying; Li, Ning; Cui, Mei; Xiong, Zhi-li; Li, Fa-mei

2012-10-01

To study the effect of phenformin hydrochloride that may be illegally added in traditional Chinese medicine preparations on the pharmacokinetics of puerarin in rats. Rats were randomly divided into the single pueraria group and the phenformin hydrochloride combined with pueraria group. After oral administration in the two groups, their bloods were sampled at different time points to determine the drug concentration of puerarin in rat blood and calculate pharmacokinetic parameters. After oral administration with pueraria extracts and phenformin hydrochloride combined with pueraria extracts, the two groups showed main pharmacokinetic parameters as follows: Cmax were (2.39 +/- 1.01), (1.03 +/- 0.35) mg x L(-1), respectively; Tmax were (0.50 +/- 0.09), (1.5 +/- 0.5) h, respectively; Ke were (0.153 +/- 0.028), (0.172 +/- 0.042) h(-1), respectively; t(1/2) were (4.65 +/- 0.86), (4.20 +/- 0.81) h, respectively; AUC(0-t), were (5.73 +/- 2.60), (5.45 +/- 1.81) mg x h x L(-1), respectively; AUC(0-infinity) were (6.72 +/- 2.89), (6.26 +/- 1.88) mg x h x L(-1), respectively. Compared with the single puerarin group, the Cmax was significantly decreased (P < 0.05) and the Tmax was markedly longer (P < 0.01) than the hydrochloride combined with pueraria group. Phenformin hydrochloride can slow down the absorption process of puerarin and change the pharmacokinetic process of puerarin to some extent.

Eye surface temperature detects stress response in budgerigars (Melopsittacus undulatus).

PubMed

Ikkatai, Yuko; Watanabe, Shigeru

2015-08-05

Previous studies have suggested that stressors not only increase body core temperature but also body surface temperature in many animals. However, it remains unclear whether surface temperature could be used as an alternative to directly measure body core temperature, particularly in birds. We investigated whether surface temperature is perceived as a stress response in budgerigars. Budgerigars have been used as popular animal models to investigate various neural mechanisms such as visual perception, vocal learning, and imitation. Developing a new technique to understand the basic physiological mechanism would help neuroscience researchers. First, we found that cloacal temperature correlated with eye surface temperature. Second, eye surface temperature increased after handling stress. Our findings suggest that eye surface temperature is closely related to cloacal temperature and that the stress response can be measured by eye surface temperature in budgerigars.

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Rayner, Nick

2017-04-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-June 2018, https://www.eustaceproject.eu) we are developing an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods. We will present recent progress along this road in the EUSTACE project: 1. providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; 2. identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; 3. estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; 4. using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Ghent, D.; Rayner, N. A.

2016-12-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-June 2018, https://www.eustaceproject.eu) we are developing an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods. We will present recent progress along this road in the EUSTACE project, i.e.: • providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

Preparation and pharmacokinetics in beagle dogs of ganershu sustained-release pellets

PubMed Central

Pan, Jin-huo; Wang, Jian-chun; Jiang, Zhi-tao; Zhang, Ting; Ge, Shao-bo; Zhang, Ye-xia; Jin, Xin; Yan, Guo-jun

2014-01-01

Background: The active ingredients of Ganershu compound recipe, which are effective for hepatitis treatment in liver protection and transaminase reduction. However, the active ingredients of Ganershu compound recipe are poor absorption, which conduct it has a low oral bioavailability. Objective: We prepared Ganershu sustained-release pellets (GSPs) by fluidized-bed on central composite design-response surface methodology and increase its bioavailability in beagle dogs. Materials and Methods: In this study, GSPs were successfully prepared. The Drug-loaded pellets and sustained-release coated were carried out in fluidized-bed machine. GSP was optimized for fitting release, roundness, and the overall desirability by central composite design-response surface methodology. Results: To optimize cumulative release profile, the outermost ethyl cellulose coating layer and the hydroxypropyl methyl cellulose (HPMC) swelling layer were employed, which were respectively given coating levels in terms of weight gain of 22% and 6%, the concentration of HPMC is 4.5% (g/ml). The pharmacokinetics of Ganershu normal pellets (GNPs) and GSP was studied in beagle dogs after oral administration. The naringenin as an index, the area under the curve0-∞ of naringenin in GSP was 1.38 times greater than that of GNP. Meanwhile, Tmax of GSP was prolonged for about 74%. Conclusion: This study can clearly indicate that we enhanced the oral bioavailability of Ganershu by preparing the GSP, which had the sustained dissolution and improved the potential of it for clinical application. PMID:25210307

Design and Optimization of Domperidone Fast Dissolving Tablet Using Central Composite Design.

PubMed

Shailendra, Bhatt; Shailendra, Mandge; Manish, Jaimini; Singh, Tanwar Yuveraj; Priti, Trivedi

2015-01-01

The main aim present work was to optimize fast dissolving tablet (FDT) formulation using response surface approach. The variables studied were sodium bicarbonate (X1), citric acid (X2), and superdisintegrant, Ac-Di-Sol (X3). The main aspect of present work was to develop FDT of Domperidone which possesses fast disintegration and high mechanical strength. It was found that the response was affected by all the three factors studied. The statistical models were successfully used to prepare FDT of Domperidone with fast disintegration (31.08 seconds) and adequate hardness (4.1 kg/cm(2)). Pharmacokinetic studies in rats showed statistically insignificant difference (p>0.05) between Domperidone fast dissolving tablet (DFDT) and market product. This concluded that optimized FDT is bioequivalent with the marketed formulation. The values of Tmax were found to be 0.5 h and 0.75 h for DFDT and reference product, respectively. Conditioned place aversion study was performed on Swiss Albino mice and the study showed the better anti emetic potency of optimized FDT in nauseated condition over market product (p<0.05). Thus, the present investigation conclusively demonstrates the potential role in terms of rapid disintegration and high mechanical strength.

Single-Dose Pharmacokinetics and Safety of Abacavir (1592U89), Zidovudine, and Lamivudine Administered Alone and in Combination in Adults with Human Immunodeficiency Virus Infection

PubMed Central

Wang, Laurene H.; Chittick, Gregory E.; McDowell, James A.

1999-01-01

Abacavir (1592U89), a nucleoside reverse transcriptase inhibitor with in vitro activity against human immunodeficiency virus type-1 (HIV-1), has been evaluated for efficacy and safety in combination regimens with other nucleoside analogs, including zidovudine (ZDV) and lamivudine (3TC). To evaluate the potential pharmacokinetic interactions between these agents, 15 HIV-1-infected adults with a median CD4+ cell count of 347 cells/mm3 (range, 238 to 570 cells/mm3) were enrolled in a randomized, seven-period crossover study. The pharmacokinetics and safety of single doses of abacavir (600 mg), ZDV (300 mg), and 3TC (150 mg) were evaluated when each drug was given alone or when any two or three drugs were given concurrently. The concentrations of all drugs in plasma and the concentrations of ZDV and its 5′-glucuronide metabolite, GZDV, in urine were measured for up to 24 h postdosing, and pharmacokinetic parameter values were calculated by noncompartmental methods. The maximum drug concentration (Cmax), the area under the concentration-time curve from time zero to infinity (AUC0–∞), time to Cmax (Tmax), and apparent elimination half-life (t1/2) of abacavir in plasma were unaffected by coadministration with ZDV and/or 3TC. Coadministration of abacavir with ZDV (with or without 3TC) decreased the mean Cmax of ZDV by approximately 20% (from 1.5 to 1.2 μg/ml), delayed the median Tmax for ZDV by 0.5 h, increased the mean AUC0–∞ for GZDV by up to 40% (from 11.8 to 16.5 μg · h/ml), and delayed the median Tmax for GZDV by approximately 0.5 h. Coadministration of abacavir with 3TC (with or without ZDV) decreased the mean AUC0–∞ for 3TC by approximately 15% (from 5.1 to 4.3 μg · h/ml), decreased the mean Cmax by approximately 35% (from 1.4 to 0.9 μg/ml), and delayed the median Tmax by approximately 1 h. While these changes were statistically significant, they are similar to the effect of food intake (for ZDV) or affect an inactive metabolite (for GZDV) or are relatively minor (for 3TC) and are therefore not considered to be clinically significant. No significant differences were found in the urinary recoveries of ZDV or GZDV when ZDV was coadministered with abacavir. There was no pharmacokinetic interaction between ZDV and 3TC. Mild to moderate headache, nausea, lymphadenopathy, hematuria, musculoskeletal chest pain, neck stiffness, and fever were the most common adverse events reported by those who received abacavir. Coadministration of ZDV or 3TC with abacavir did not alter this adverse event profile. The three-drug regimen was primarily associated with gastrointestinal events. In conclusion, no clinically significant pharmacokinetic interactions occurred between abacavir, ZDV, and 3TC in HIV-1-infected adults. Coadministration of abacavir with ZDV or 3TC produced mild changes in the absorption and possibly the urinary excretion characteristics of ZDV-GZDV and 3TC that were not considered to be clinically significant. Coadministration of abacavir with ZDV and/or 3TC was generally well tolerated and did not produce unexpected adverse events. PMID:10390227

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Ghent, D.; Rayner, N. A.

2017-12-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-2018, https://www.eustaceproject.eu) we have developed an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. This includes developing new "Big Data" analysis methods as the data volumes involved are considerable. We will present recent progress along this road in the EUSTACE project, i.e.: • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

Differences between near-surface equivalent temperature and temperature trends for the Eastern United States. Equivalent temperature as an alternative measure of heat content

USGS Publications Warehouse

Davey, C.A.; Pielke, R.A.; Gallo, K.P.

2006-01-01

There is currently much attention being given to the observed increase in near-surface air temperatures during the last century. The proper investigation of heating trends, however, requires that we include surface heat content to monitor this aspect of the climate system. Changes in heat content of the Earth's climate are not fully described by temperature alone. Moist enthalpy or, alternatively, equivalent temperature, is more sensitive to surface vegetation properties than is air temperature and therefore more accurately depicts surface heating trends. The microclimates evident at many surface observation sites highlight the influence of land surface characteristics on local surface heating trends. Temperature and equivalent temperature trend differences from 1982-1997 are examined for surface sites in the Eastern U.S. Overall trend differences at the surface indicate equivalent temperature trends are relatively warmer than temperature trends in the Eastern U.S. Seasonally, equivalent temperature trends are relatively warmer than temperature trends in winter and are relatively cooler in the fall. These patterns, however, vary widely from site to site, so local microclimate is very important. ?? 2006 Elsevier B.V. All rights reserved.

An Examination of Intertidal Temperatures Through Remotely Sensed Satellite Observations

NASA Astrophysics Data System (ADS)

Lakshmi, V.

2010-12-01

MODIS Aqua and Terra satellites produce both land surface temperatures and sea surface temperatures using calibrated algorithms. In this study, the land surface temperatures were retrieved during clear-sky (non-cloudy) conditions at a 1 km2 resolution (overpass time at 10:30 am) whereas the sea surface temperatures are also retrieved during clear-sky conditions at approximately 4 km resolution (overpass time at 1:30 pm). The purpose of this research was to examine remotely sensed sea surface (SST), intertidal (IST), and land surface temperatures (LST), in conjunction with observed in situ mussel body temperatures, as well as associated weather and tidal data. In Strawberry Hill, Oregon, it was determined that intertidal surface temperatures are similar to but distinctly different from land surface temperatures although influenced by sea surface temperatures. The air temperature and differential heating throughout the day, as well as location in relation to the shore, can greatly influence the remotely sensed surface temperatures. Therefore, remotely sensed satellite data is a very useful tool in examining intertidal temperatures for regional climatic changes over long time periods and may eventually help researchers forecast expected climate changes and help determine associated biological implications.

Optical Properties of Zinc Selenide Grown Using Molecular Beam Deposition Techniques

DTIC Science & Technology

1989-06-01

studied were grown using a standard MBE machine with insitu diagnostics. The ZnSe material used for growing the samples is highly pure polycrystalline...width of the interference maxima n can be found from equation (1). Beyond 550 nm absorption is varying rapidly and this will cause Tmax to vary...nonlinearity Is utilized - such as in an optically bistable switch. It is known from previous work on ZnSe grown on GaAs 113] that the material begins growing

Temporal Aspects of the V[o.sub.2] Response at the Power Output Associated with V[o.sub.2]peak in Well Trained Cyclists-Implications for Interval Training Prescription

ERIC Educational Resources Information Center

Laursen, Paul B.; Shing, Cecilia M.; Jenkins, David G.

2004-01-01

The power output achieved at peak oxygen consumption (V[O.sub.2]peak) and the time this power can be maintained (i.e., Tmax) have been used in prescribing high-intensity interval training. In this context, the present study examined temporal aspects of the V[O.sub.2] response to exercise at the cycling power that output well trained cyclists…

Inventory of File gfs.t06z.smartguam03.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 3 hour fcst Dew Point Temperature [K] 003 surface SPFH 3 hour fcst Specific surface 4LFTX 3 hour fcst Best (4 layer) Lifted Index [K] 019 surface TMP 2 hour fcst Temperature [K] 020 surface TMP 1 hour fcst Temperature [K] 021 surface DPT 2 hour fcst Dew Point Temperature [K] 022 surface

Differential response of surface temperature and atmospheric temperature to the biogeophysical effects of deforestation

NASA Astrophysics Data System (ADS)

Winckler, J.; Reick, C. H.; Lejeune, Q.; Pongratz, J.

2017-12-01

Deforestation influences temperature locally by changing the water, energy and momentum balance. While most observation-based studies and some modeling studies focused on the effects on surface temperature, other studies focused on the effects on near-surface air temperature. However, these two variables may respond differently to deforestation because changes in albedo and surface roughness may alter the land-atmosphere coupling and thus the vertical temperature distribution. Thus it is unclear whether it is possible to compare studies that assess the impacts of deforestation on these two different variables. Here, we analyze the biogeophysical effects of global-scale deforestation in the climate model MPI-ESM separately for surface temperature, 2m-air temperature and temperature the lowest atmospheric model layer. We investigate why the response of these variables differs by isolating the effects of only changing surface albedo and only changing surface roughness and by separating effects that are induced at the location of deforestation (local effects) from effects that are induced by advection and changes in circulation (nonlocal effects). Concerning surface temperature, we find that the local effects of deforestation lead to a global mean warming which is overcompensated by the nonlocal effects (up to 0.1K local warming versus -0.3K nonlocal cooling). The surface warming in the local effects is largely driven by the change in surface roughness while the cooling in the nonlocal effects is largely driven by the change in surface albedo. The nonlocal effects are largely consistent across surface temperature, 2m-air temperature, and the temperature of the lowest atmospheric layer. However, the local effects strongly differ across the three considered variables. The local effects are strong for surface temperature, but substantially weaker in the 2m-air temperature and largely absent in the lowest atmospheric layer. We conclude that studies focusing on the deforestation effects on surface temperature should not be compared to studies focusing on the effects on air temperature. While the local effects on surface temperature are useful for model evaluation, they might be less relevant for local adaptation and mitigation than previously thought because they might largely be absent in the atmosphere.

Influence of oxygen partial pressure on surface tension and its temperature coefficient of molten iron

NASA Astrophysics Data System (ADS)

Ozawa, S.; Suzuki, S.; Hibiya, T.; Fukuyama, H.

2011-01-01

Influences of oxygen partial pressure, PO2, of ambient atmosphere and temperature on surface tension and its temperature coefficient for molten iron were experimentally investigated by an oscillating droplet method using an electromagnetic levitation furnace. We successfully measured the surface tension of molten iron over a very wide temperature range of 780 K including undercooling condition in a well controlled PO2 atmosphere. When PO2 is fixed at 10-2 Pa at the inlet of the chamber, a "boomerang shape" temperature dependence of surface tension was experimentally observed; surface tension increased and then decreased with increasing temperature. The pure surface tension of molten iron was deduced from the negative temperature coefficient in the boomerang shape temperature dependence. When the surface tension was measured under the H2-containing gas atmosphere, surface tension did not show a linear relationship against temperature. The temperature dependence of the surface tension shows anomalous kink at around 1850 K due to competition between the temperature dependence of PO2 and that of the equilibrium constant of oxygen adsorption.

Recent Climate Changes in Northwestern Qaidam Basin Inferred from Geothermal Gradients

NASA Astrophysics Data System (ADS)

Liu, J.; Zhang, T.

2014-12-01

Temperature perturbations under the ground surface are direct thermal response to ground surface temperature changes. Thus ground surface temperature history can be reconstructed from borehole temperature measurements using borehole paleothermometry inversion method. In this study, we use seven borehole temperature profiles to reconstruct the ground surface temperature variation of the past 500 years of the Qaidam basin, northwestern China. Borehole transient temperature measurement from seven sites in northwestern Qaidam basin were separated from geothermal gradients and analyzed by functional space inversion method to determine past ground surface temperature variations in this region. All temperature profiles show the effects of recent climatic disturbances. Inversion shows an overall increase in ground surface temperature by an averaged 1.2℃ (-0.11~2.21℃) during the last 500 years. Clear signs of a cold period between 1500 and 1900 A.D., corresponding to the Little Ice Age, have been found. Its coldest period was between 1780~1790 A.D. with the ground surface temperature of 5.4℃. During the 19th and the 20th century, reconstructed ground surface temperature shows a rising trend, and in the late 20th century, the temperature started to decrease. However, the highest temperature in 1990s broke the record of the past 500 years. This reconstructed past ground surface temperature variation is verified by the simulated annual surface air temperature computed by EdGCM and the cooling trend is also confirmed by other reconstruction of winter half year minimum temperatures using tree rings on the northeastern Tibetan Plateau.

Inventory of File nam.t00z.smartconus06.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 6 hour fcst Dew Point Temperature [K] 003 surface SPFH 6 hour fcst Specific Index [K] 027 surface HINDEX 6 hour fcst Haines Index [Numeric] 028 surface TMP 5 hour fcst Temperature [K] 029 surface TMP 4 hour fcst Temperature [K] 030 surface DPT 5 hour fcst Dew Point Temperature [K

Inventory of File gfs.t06z.smartguam12.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 12 hour fcst Dew Point Temperature [K] 003 surface SPFH 12 hour fcst Specific Best (4 layer) Lifted Index [K] 020 surface TMP 11 hour fcst Temperature [K] 021 surface TMP 10 hour fcst Temperature [K] 022 surface DPT 11 hour fcst Dew Point Temperature [K] 023 surface DPT 10 hour

Inventory of File nam.t00z.smartak06.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 6 hour fcst Dew Point Temperature [K] 003 surface SPFH 6 hour fcst Specific Haines Index [Numeric] 029 surface TMP 5 hour fcst Temperature [K] 030 surface TMP 4 hour fcst Temperature [K] 031 surface DPT 5 hour fcst Dew Point Temperature [K] 032 surface DPT 4 hour fcst Dew Point

Inventory of File nam.t00z.smartconus12.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 12 hour fcst Dew Point Temperature [K] 003 surface SPFH 12 hour fcst Specific hour fcst Haines Index [Numeric] 030 surface TMP 11 hour fcst Temperature [K] 031 surface TMP 10 hour fcst Temperature [K] 032 surface DPT 11 hour fcst Dew Point Temperature [K] 033 surface DPT 10 hour

Cross-scale modeling of surface temperature and tree seedling establishment inmountain landscapes

USGS Publications Warehouse

Dingman, John; Sweet, Lynn C.; McCullough, Ian M.; Davis, Frank W.; Flint, Alan L.; Franklin, Janet; Flint, Lorraine E.

2013-01-01

Abstract: Introduction: Estimating surface temperature from above-ground field measurements is important for understanding the complex landscape patterns of plant seedling survival and establishment, processes which occur at heights of only several centimeters. Currently, future climate models predict temperature at 2 m above ground, leaving ground-surface microclimate not well characterized. Methods: Using a network of field temperature sensors and climate models, a ground-surface temperature method was used to estimate microclimate variability of minimum and maximum temperature. Temperature lapse rates were derived from field temperature sensors and distributed across the landscape capturing differences in solar radiation and cold air drainages modeled at a 30-m spatial resolution. Results: The surface temperature estimation method used for this analysis successfully estimated minimum surface temperatures on north-facing, south-facing, valley, and ridgeline topographic settings, and when compared to measured temperatures yielded an R2 of 0.88, 0.80, 0.88, and 0.80, respectively. Maximum surface temperatures generally had slightly more spatial variability than minimum surface temperatures, resulting in R2 values of 0.86, 0.77, 0.72, and 0.79 for north-facing, south-facing, valley, and ridgeline topographic settings. Quasi-Poisson regressions predicting recruitment of Quercus kelloggii (black oak) seedlings from temperature variables were significantly improved using these estimates of surface temperature compared to air temperature modeled at 2 m. Conclusion: Predicting minimum and maximum ground-surface temperatures using a downscaled climate model coupled with temperature lapse rates estimated from field measurements provides a method for modeling temperature effects on plant recruitment. Such methods could be applied to improve projections of species’ range shifts under climate change. Areas of complex topography can provide intricate microclimates that may allow species to redistribute locally as climate changes.

Climate effect on forest fire static risk assessment

NASA Astrophysics Data System (ADS)

Bodini, Antonella; Cossu, Antonello; Entrade, Erika; Fiorucci, Paolo; Gaetani, Francesco; Parodi, Ulderica

2010-05-01

The availability of a long data series of fire perimeters combined with a detailed knowledge of topography and land cover allow to understand which are the main features involved in forest fire occurrences and their behaviour. In addition, climate indexes obtained from the analysis of time series with more than 20 years of complete records allow to understand the role of climate on fire regime, both in terms of direct effects on fire behaviour and the effect on vegetation cover. In particular, indices of extreme events have been considered like CDD (maximum number of consecutive dry days) and HWDI (heat wave duration index: maximum period > 5 consecutive days with Tmax >5°C above the 1961-1990 daily Tmax normal), together with the usual indices describing rainfall and temperature regimes. As a matter of fact, based on this information it is possible to develop statistical methods for the objective classification of forest fire static risk at regional scale. Two different case studies are presented in this work: Regione Liguria and Regione Sardegna (Italy). Both regions are in the center of the Mediterranean and are characterized by a high number of fires and burned area. However, the two regions have very different fire regimes. Sardinia is affected by the fire phenomenon only in summer whilst Liguria is affected by fires also in winter, with higher number of fires and larger burned area. In addition, the two region are very different in vegetation cover. The presence of Mediterranean conifers, (Pinus Pinaster, Pinus Nigra, Pinus halepensis) is quite spread in Liguria and is almost absent in Sardinia. What is common in the two regions is the widespread presence of shrub species frequently spread by fire. The analysis in the two regions thus allows in a rather limited area to consider almost all the species and the climate conditions that characterize the Mediterranean region. More than 10000 fire perimeters that burnt about 800 km2 were considered in the analysis. The analysis has been carried out at 20 m spatial resolution. Some important considerations relating to climate and the territorial features that characterize the fire regime in the considered regions contribute to better understand the forest fire phenomena. These results allow to define new strategies for forest fire prevention and management extendable to other geographical areas. This research is part of the project PROTERINA C, funded by the EU under the Italy-France Maritime Programme, aiming at investigating the effects that climate change could have on the environment (fuels).

Temperature distribution and heat radiation of patterned surfaces at short wavelengths.

PubMed

Emig, Thorsten

2017-05-01

We analyze the equilibrium spatial distribution of surface temperatures of patterned surfaces. The surface is exposed to a constant external heat flux and has a fixed internal temperature that is coupled to the outside heat fluxes by finite heat conductivity across the surface. It is assumed that the temperatures are sufficiently high so that the thermal wavelength (a few microns at room temperature) is short compared to all geometric length scales of the surface patterns. Hence the radiosity method can be employed. A recursive multiple scattering method is developed that enables rapid convergence to equilibrium temperatures. While the temperature distributions show distinct dependence on the detailed surface shapes (cuboids and cylinder are studied), we demonstrate robust universal relations between the mean and the standard deviation of the temperature distributions and quantities that characterize overall geometric features of the surface shape.

Temperature distribution and heat radiation of patterned surfaces at short wavelengths

NASA Astrophysics Data System (ADS)

Emig, Thorsten

2017-05-01

We analyze the equilibrium spatial distribution of surface temperatures of patterned surfaces. The surface is exposed to a constant external heat flux and has a fixed internal temperature that is coupled to the outside heat fluxes by finite heat conductivity across the surface. It is assumed that the temperatures are sufficiently high so that the thermal wavelength (a few microns at room temperature) is short compared to all geometric length scales of the surface patterns. Hence the radiosity method can be employed. A recursive multiple scattering method is developed that enables rapid convergence to equilibrium temperatures. While the temperature distributions show distinct dependence on the detailed surface shapes (cuboids and cylinder are studied), we demonstrate robust universal relations between the mean and the standard deviation of the temperature distributions and quantities that characterize overall geometric features of the surface shape.

Near-surface temperature inversion during summer at Summit, Greenland, and its relation to MODIS-derived surface temperatures

NASA Astrophysics Data System (ADS)

Adolph, Alden C.; Albert, Mary R.; Hall, Dorothy K.

2018-03-01

As rapid warming of the Arctic occurs, it is imperative that climate indicators such as temperature be monitored over large areas to understand and predict the effects of climate changes. Temperatures are traditionally tracked using in situ 2 m air temperatures and can also be assessed using remote sensing techniques. Remote sensing is especially valuable over the Greenland Ice Sheet, where few ground-based air temperature measurements exist. Because of the presence of surface-based temperature inversions in ice-covered areas, differences between 2 m air temperature and the temperature of the actual snow surface (referred to as skin temperature) can be significant and are particularly relevant when considering validation and application of remote sensing temperature data. We present results from a field campaign extending from 8 June to 18 July 2015, near Summit Station in Greenland, to study surface temperature using the following measurements: skin temperature measured by an infrared (IR) sensor, 2 m air temperature measured by a National Oceanic and Atmospheric Administration (NOAA) meteorological station, and a Moderate Resolution Imaging Spectroradiometer (MODIS) surface temperature product. Our data indicate that 2 m air temperature is often significantly higher than snow skin temperature measured in situ, and this finding may account for apparent biases in previous studies of MODIS products that used 2 m air temperature for validation. This inversion is present during our study period when incoming solar radiation and wind speed are both low. As compared to our in situ IR skin temperature measurements, after additional cloud masking, the MOD/MYD11 Collection 6 surface temperature standard product has an RMSE of 1.0 °C and a mean bias of -0.4 °C, spanning a range of temperatures from -35 to -5 °C (RMSE = 1.6 °C and mean bias = -0.7 °C prior to cloud masking). For our study area and time series, MODIS surface temperature products agree with skin surface temperatures better than previous studies indicated, especially at temperatures below -20 °C, where other studies found a significant cold bias. We show that the apparent cold bias present in other comparisons of 2 m air temperature and MODIS surface temperature may be a result of the near-surface temperature inversion. Further investigation of how in situ IR skin temperatures compare to MODIS surface temperature at lower temperatures (below -35 °C) is warranted to determine whether a cold bias exists for those temperatures.

Preclinical pharmacokinetic characterization of 2-(4-(4-(5-(2-phenyl-5-(trifluoromethyl)oxazole-4-carboxamido)-1H-benzo[d]imidazol-2-yl)phenyl)cyclohexyl) acetic acid, a novel DGAT-1 inhibitor.

PubMed

Kwak, Eun-Young; Im, So Hee; Seo, Hyewon; Cho, Woon-Ki; Lee, Ye-Lim; Woo, Jaechun; Ahn, Sunjoo; Ahn, Sung-Hoon; Kwak, Hyun Jung; Ahn, Jin Hee; Bae, Myung Ae; Song, Jin Sook

2014-05-01

1. A novel diacylglyceride acyltransferase-1 (DGAT-1) inhibitor, 2-(4-(4-(5-(2-phenyl-5-(trifluoromethyl) oxazole-4-carboxamido)-1H-benzo[d]imidazol-2-yl)phenyl)cyclohexyl) acetic acid (KR-69232), was synthesized for a potential therapeutic use against several metabolic disorders, such as obesity, insulin resistance, and type II diabetes, characterized by excessive triglycerides (TGs) in the blood. 2. The half-lives against phase I metabolism were measured as 75.3 ± 20.9 min and over 120 min in rat and human liver microsomes, respectively. In Caco-2 cell monolayers, extremely low permeability (<0.13 × 10⁻⁶cm/s) was seen in the absorptive direction, predicting limited intestinal absorption of KR-69232. This compound was highly bound to rat and human plasma proteins (>99.8%). 3. With the intravenous administration of KR-69232 in rats (1, 2, and 5 mg/kg), non-linear kinetics were observed at the highest dose, with significantly higher systemic clearance, higher volume of distribution, and lower dose-normalized AUC. Following oral administration, it exhibited low bioavailability (<10%) and was absorbed slowly (T(max), 3.8-5.2 h) over the dose range. We also confirmed that considerable KR-69232 remained in the intestine at T(max), demonstrating its limited absorption into the systemic circulation.

Serum oxidizability and antioxidant status in patients undergoing in vitro fertilization.

PubMed

Aurrekoetxea, Igor; Ruiz-Sanz, José Ignacio; del Agua, Ainhoa Ruiz; Navarro, Rosaura; Hernández, M Luisa; Matorras, Roberto; Prieto, Begoña; Ruiz-Larrea, M Begoña

2010-09-01

To evaluate the serum oxidizability and antioxidant status in women undergoing an in vitro fertilization (IVF) cycle and to assess the possible relationship of the oxidizability indexes with the pregnancy rate. Prospective, longitudinal study. Public university and public university hospital. Systematically recruited cohort of 125 women undergoing either IVF or intracytoplasmic sperm injection (ICSI). Serum samples were collected before the beginning of the use of gonadotropins (basal) and the day of human chorionic gonadotropin (hCG) administration (final) during an IVF cycle. The Cu2+-induced serum oxidation in terms of the oxidation rate in the lag (Vlag) and propagation (Vmax) phases and the time at which the oxidation rate is maximal (tmax), and measurements of serum total antioxidant activity (TAA), tocopherol, hydrophilic antioxidants, malondialdehyde, and nitric oxide. Albumin, urate, bilirubin, alpha-tocopherol and gamma-tocopherol, TAA, and tmax statistically significantly decreased after the IVF cycle. Conception cycles were associated with a serum more prone to oxidation compared with nonconception cycles. In multivariate logistic regression analysis, the difference (final-basal) of the oxidation index Vlag (OR 1.394) and the body mass index (OR 0.785) were independent predictors of pregnancy. Treatment with IVF induces the production of reactive oxygen species (ROS), which is reflected in a serum less protected against oxidation. The results also suggest a role for ROS in the occurrence of conception in IVF. Copyright (c) 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Bioavailability of rifampicin in a separate formulation and fixed dose combination with isoniazid NIH: a case for a fixed dose combination (FDC) for the treatment of tuberculosis.

PubMed

Nyazema, N Z; Rabvukwa, P; Gumbo, J; Ndudzo, P; Chitemerere, C

1999-06-01

To study and compare the bioavailability of rifampicin (RIF), in two locally manufactured formulations; an FDC and a separate formulation and an imported FDC formulation. Open within subjects, single blind cross over study. Each volunteer subject, acting as their own control, received the two fixed dose combinations and the separate formulation with the same amount of 450 mg RIF. Cmax (peak drug concentration achieved), Tmax (time at which peak drug concentration is achieved), T1/2el (biological half-life of elimination) and area under the curve (AUC) for zero to 10 hours and zero to infinity. These are obtained from plotting plasma concentration against time. There was a significant difference in the Cmax between free and RIF combined with INH (6.1 and 7.6 mg/l respectively) and no significant difference in the other parameters measured, of the local products. Comparison of the local products and imported product showed no significant difference in AUC but significant differences in T1/2el, C max and Tmax (p = 0.003, 0.041 and 0.025 respectively). The Zimbabwe manufactured and the German products had "demonstrable bioavailability" as defined by the International Union Against Tuberculosis and Lung Diseases (IUATLD). The local manufacturer appeared to have the technological capability to produce a registrable combined RIF/INH table to be used in the treatment of tuberculosis and to prevent the irrational use of RIF.

Effect of probiotics on enrofloxacin disposition in gastrointestinal tract of poultry.

PubMed

Pavlova, I; Danova, S; Naidenski, H; Tropcheva, R; Milanova, A

2015-12-01

Probiotics are routinely used in poultry husbandry due to health benefit on the host. The gut microbiota is now recognized to exert an important influence on the absorption and pharmacokinetics of many compounds. Therefore, this study was designed to evaluate the effect of candidate probiotics belonging to the species Lactobacillus brevis, L. plantarum and L. bulgaricus on pharmacokinetics of enrofloxacin in healthy chickens. The probiotic administration leads to higher degree of metabolism of enrofloxacin to ciprofloxacin in liver. The antibacterial drug was significantly faster absorbed (kab of 0.61 ± 0.54 h(-1) and Tmax 7.81 ± 3.52 h) at lower concentrations (Cmax of 1.34 ± 0.18 μg·g(-1)) during the first 24 h of treatment in the probiotic's group. The values of kab , Tmax , and Cmax for the group, treated solely with enrofloxacin, were 0.10 ± 0.065 h(-1), 15.42 ± 3.07 h, and 1.61 ± 0.24 μg·g(-1), respectively. A significantly higher concentration of enrofloxacin and its metabolite ciprofloxacin in the liver was observed in the group with the probiotic treatment. Disposition of both drugs was not significantly changed in the duodenum and in the jejunum. The selected dose is appropriate for treatment of infections caused by pathogens with MIC < 0.06 μg·mL(-1) irrespective of antibiotic administration alone or in combination with probiotics. © 2015 John Wiley & Sons Ltd.

Influence of chocolate matrix composition on cocoa flavan-3-ol bioaccessibility in vitro and bioavailability in humans.

PubMed

Neilson, Andrew P; George, Judy C; Janle, Elsa M; Mattes, Richard D; Rudolph, Ralf; Matusheski, Nathan V; Ferruzzi, Mario G

2009-10-28

Conflicting data exist regarding the influence of chocolate matrices on the bioavailability of epicatechin (EC) from cocoa. The objective of this study was to assess the bioavailability of EC from matrices varying in macronutrient composition and physical form. EC bioavailability was assessed from chocolate confections [reference dark chocolate (CDK), high sucrose (CHS), high milk protein (CMP)] and cocoa beverages [sucrose milk protein (BSMP), non-nutritive sweetener milk protein (BNMP)], in humans and in vitro. Six subjects consumed each product in a randomized crossover design, with serum EC concentrations monitored over 6 h post consumption. Areas under the serum concentration-time curve (AUC) were similar among chocolate matrices. However, AUCs were significantly increased for BSMP and BNMP (132 and 143 nM h) versus CMP (101 nM h). Peak serum concentrations (C(MAX)) were also increased for BSMP and BNMP (43 and 42 nM) compared to CDK and CMP (32 and 25 nM). Mean T(MAX) values were lower, although not statistically different, for beverages (0.9-1.1 h) versus confections (1.8-2.3 h), reflecting distinct shapes of the pharmacokinetic curves for beverages and confections. In vitro bioaccessibility and Caco-2 accumulation did not differ between treatments. These data suggest that bioavailability of cocoa flavan-3-ols is likely similar from typical commercial cocoa based foods and beverages, but that the physical form and sucrose content may influence T(MAX) and C(MAX).

Inventory of File nam.t00z.smartak03.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 3 hour fcst Dew Point Temperature [K] 003 surface SPFH 3 hour fcst Specific fcst Haines Index [Numeric] 026 surface TMP 2 hour fcst Temperature [K] 027 surface TMP 1 hour fcst Temperature [K] 028 surface DPT 2 hour fcst Dew Point Temperature [K] 029 surface DPT 1 hour fcst Dew Point

Retrieval of surface temperature by remote sensing. [of earth surface using brightness temperature of air pollutants

NASA Technical Reports Server (NTRS)

Gupta, S. K.; Tiwari, S. N.

1976-01-01

A simple procedure and computer program were developed for retrieving the surface temperature from the measurement of upwelling infrared radiance in a single spectral region in the atmosphere. The program evaluates the total upwelling radiance at any altitude in the region of the CO fundamental band (2070-2220 1/cm) for several values of surface temperature. Actual surface temperature is inferred by interpolation of the measured upwelling radiance between the computed values of radiance for the same altitude. Sensitivity calculations were made to determine the effect of uncertainty in various surface, atmospheric and experimental parameters on the inferred value of surface temperature. It is found that the uncertainties in water vapor concentration and surface emittance are the most important factors affecting the accuracy of the inferred value of surface temperature.

Surface Emissivity Effects on Thermodynamic Retrieval of IR Spectral Radiance

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Larar, Allen M.; Smith, William L.; Liu, Xu

2006-01-01

The surface emissivity effect on the thermodynamic parameters (e.g., the surface skin temperature, atmospheric temperature, and moisture) retrieved from satellite infrared (IR) spectral radiance is studied. Simulation analysis demonstrates that surface emissivity plays an important role in retrieval of surface skin temperature and terrestrial boundary layer (TBL) moisture. NAST-I ultraspectral data collected during the CLAMS field campaign are used to retrieve thermodynamic properties of the atmosphere and surface. The retrievals are then validated by coincident in-situ measurements, such as sea surface temperature, radiosonde temperature and moisture profiles. Retrieved surface emissivity is also validated by that computed from the observed radiance and calculated emissions based on the retrievals of surface temperature and atmospheric profiles. In addition, retrieved surface skin temperature and emissivity are validated together by radiance comparison between the observation and retrieval-based calculation in the window region where atmospheric contribution is minimized. Both simulation and validation results have lead to the conclusion that variable surface emissivity in the inversion process is needed to obtain accurate retrievals from satellite IR spectral radiance measurements. Retrieval examples are presented to reveal that surface emissivity plays a significant role in retrieving accurate surface skin temperature and TBL thermodynamic parameters.

California heat waves: their spatial evolution, variation, and coastal modulation by low clouds

NASA Astrophysics Data System (ADS)

Clemesha, Rachel E. S.; Guirguis, Kristen; Gershunov, Alexander; Small, Ivory J.; Tardy, Alexander

2018-06-01

We examine the spatial and temporal evolution of heat waves through California and consider one of the key modulating factors of summertime coastal climate—coastal low cloudiness (CLC). Heat waves are defined relative to daytime maximum temperature (Tmax) anomalies after removing local seasonality and capture unseasonably warm events during May—September. California is home to several diverse climate regions and characteristics of extreme heat events are also variable throughout these regions. Heat wave events tend to be shorter, but more anomalously intense along the coast. Heat waves typically impact both coastal and inland regions, although there is more propensity towards coastally trapped events. Most heat waves with a strong impact across regions start at the coast, proceed inland, and weaken at the coast before letting up inland. Typically, the beginning of coastal heat waves are associated with a loss of CLC, followed by a strong rebound of CLC starting close to the peak in heat wave intensity. The degree to which an inland heat wave is expressed at the coast is associated with the presence of these low clouds. Inland heat waves that have very little expression at the coast tend to have CLC present and an elevated inversion base height compared with other heat waves.

Comment on papers ``Effect of Ag substitution on the transport property and magnetoresistance of LaMnO3'' [J. Magn. Magn. Mater. 248 (2002) 26] and ``Possible magnetic phase separation in Ru-doped La0.67Ca0.33O3'' [J. Magn. Magn. Mater. 257 (2003) 195

NASA Astrophysics Data System (ADS)

Rozenberg, E.

2004-03-01

In recent papers Ye et al. (J. Magn. Magn. Mater. 248 (2002) 26) and Lakshmi et al. (J. Magn. Magn. Mater. 257 (2003) 195) reported the characteristic features of electrical resistivity ( ρ) versus temperature ( T) dependences of polycrystalline-doped manganites La 1- xAg xMnO 3 and La 0.67Ca 0.33Mn 1- xRu xO 3. Infact, two peaks on ρ( T) curve coexist: broad one at some Tmax below the Curie points ( TC) of these compounds and a sharp peak near TC. Authors interpreted such coexistence as an evidence of electronic/magnetic phase separation in the above-noted systems below its TC. It is shown in this comment that such an interpretation is obviously invalid for La 1- xAg xMnO 3 system and is very questionable for La 0.67Ca 0.33Mn 1- xRu xO 3. The simplest and natural reason for the appearance of considered features on ρ( T) dependences of polycrystalline manganites is the well-known grain-boundary effects.

An Examination of Body Temperature for the Rocky Intertidal Mussel species, Mytilus californianus, Using Remotely Sensed Satellite Observations

NASA Astrophysics Data System (ADS)

Price, J.; Liff, H.; Lakshmi, V.

2012-12-01

Temperature is considered to be one of the most important physical factors in determining organismal distribution and physiological performance of species in rocky intertidal ecosystems, especially the growth and survival of mussels. However, little is known about the spatial and temporal patterns of temperature in intertidal ecosystems or how those patterns affect intertidal mussel species because of limitations in data collection. We collected in situ temperature at Strawberry Hill, Oregon USA using mussel loggers embedded among the intertidal mussel species, Mytilus californianus. Remotely sensed surface temperatures were used in conjunction with in situ weather and ocean data to determine if remotely sensed surface temperatures can be used as a predictor for changes in the body temperature of a rocky intertidal mussel species. The data used in this study was collected between January 2003 and December 2010. The mussel logger temperatures were compared to in situ weather data collected from a local weather station, ocean data collected from a NOAA buoy, and remotely sensed surface temperatures collected from NASA's sun-synchronous Moderate Resolution Imaging Spectroradiometer aboard the Earth Observing System Aqua and EOS Terra satellites. Daily surface temperatures were collected from four pixel locations which included two sea surface temperature (SST) locations and two land surface temperature (LST) locations. One of the land pixels was chosen to represent the intertidal surface temperature (IST) because it was located within the intertidal zone. As expected, all surface temperatures collected via satellite were significantly correlated to each other and the associated in situ temperatures. Examination of temperatures from the off-shore NOAA buoy and the weather station provide evidence that remotely sensed temperatures were similar to in situ temperature data and explain more variability in mussel logger temperatures than the in situ temperatures. Our results suggest that temperatures (surface temperature and air temperature) are similar across larger spatial scales even when the type of data collection is different. Mussel logger temperatures were strongly correlated to SSTs and were not significantly different than SSTs. Sea surface temperature collected during the Aqua overpass explained 67.1% of the variation in mean monthly mussel logger temperature. When SST, LST, and IST were taken into consideration, nearly 73% of the variation in mussel logger temperature was explained. While in situ monthly air temperature and water temperature explained only 28-33% of the variation in mussel logger temperature. Our results suggests that remotely sensed surface temperatures are reliable and important measurements that can be used to better understand the effects temperature may have on intertidal mussel species in Strawberry Hill, Oregon. Remotely sensed surface temperature could act as a relative indicator of change and may be used to predict general habitat trends and drivers that could directly affect organism body temperature.

Scattering attenuation profile of the Moon: Implications for shallow moonquakes and the structure of the megaregolith

NASA Astrophysics Data System (ADS)

Gillet, K.; Margerin, L.; Calvet, M.; Monnereau, M.

2017-01-01

We report measurements of the attenuation of short period seismic waves in the Moon based on the quantitative analysis of envelope records of lunar quakes. Our dataset consists of waveforms corresponding to 62 events, including artificial and natural impacts, shallow moonquakes and deep moonquakes, recorded by the four seismometers deployed during Apollo missions 12, 14, 15 and 16. To quantify attenuation and distinguish between elastic (scattering) and inelastic (absorption) mechanisms we measure the time of arrival of the maximum of energy tmax and the coda quality factor Qc . The former is controlled by both scattering and absorption, while the latter is an excellent proxy for absorption. Consistent with the strong broadening of seismogram envelopes in the Moon, we employ diffusion theory in spherical geometry to model the propagation of seismic energy in depth-dependent scattering and absorbing media. To minimize the misfit between predicted and observed tmax for deep moonquakes and impacts, we employ a genetic algorithm and explore a large number of depth-dependent attenuation models quantified by the scattering quality factor Qsc or equivalently the wave diffusivity D, and the absorption quality factor Qi . The scattering and absorption profiles that best fit the data display very strong scattering attenuation (Qsc ≤ 10) or equivalently very low wave diffusivity (D ≈ 2 km2/s) in the first 10 km of the Moon. These values correspond to the most heterogeneous regions on Earth, namely volcanic areas. Below this surficial layer, the diffusivity rises very slowly up to a depth of approximately 80 km where Qsc and D exhibit an abrupt increase of about one order of magnitude. Below 100 km depth, Qsc increases rapidly up to approximately 2000 at a depth of about 150 km, a value similar to the one found in the Earth's mantle. By contrast, the absorption quality factor on the Moon Qi ≈ 2400 is about one order or magnitude larger than on Earth. Our results suggest the existence of an approximately 100 km thick megaregolith, which is much larger than what was previously thought. The rapid decrease of scattering attenuation below this depth is compatible with crack healing through viscoelastic mechanisms. Using our best attenuation model, we invert for the depth of shallow moonquakes based on the observed variation of tmax with epicentral distance. On average, they are found to originate from a depth of about 50 km ± 20 km, which suggests that these earthquakes are caused by the failure of deep faults in the brittle part of the Moon.

High-intensity interval training and β-hydroxy-β-methylbutyric free acid improves aerobic power and metabolic thresholds

PubMed Central

2014-01-01

Background Previous research combining Calcium β-hydroxy-β-methylbutyrate (CaHMB) and running high-intensity interval training (HIIT) have shown positive effects on aerobic performance measures. The purpose of this study was to examine the effect of β-hydroxy-β-methylbutyric free acid (HMBFA) and cycle ergometry HIIT on maximal oxygen consumption (VO2peak), ventilatory threshold (VT), respiratory compensation point (RCP) and time to exhaustion (Tmax) in college-aged men and women. Methods Thirty-four healthy men and women (Age: 22.7 ± 3.1 yrs ; VO2peak: 39.3 ± 5.0 ml · kg-1 · min-1) volunteered to participate in this double-blind, placebo-controlled design study. All participants completed a series of tests prior to and following treatment. A peak oxygen consumption test was performed on a cycle ergometer to assess VO2peak, Tmax, VT, and RCP. Twenty-six participants were randomly assigned into either a placebo (PLA-HIIT) or 3 g per day of HMBFA (BetaTor™) (HMBFA-HIIT) group. Eight participants served as controls (CTL). Participants in the HIIT groups completed 12 HIIT (80-120% maximal workload) exercise sessions consisting of 5–6 bouts of a 2:1 minute cycling work to rest ratio protocol over a four-week period. Body composition was measured with dual energy x-ray absorptiometry (DEXA). Outcomes were assessed by ANCOVA with posttest means adjusted for pretest differences. Results The HMBFA-HIIT intervention showed significant (p < 0.05) gains in VO2peak, and VT, versus the CTL and PLA-HIIT group. Both PLA-HIIT and HMBFA-HIIT treatment groups demonstrated significant (p < 0.05) improvement over CTL for Tmax, and RCP with no significant difference between the treatment groups. There were no significant differences observed for any measures of body composition. An independent-samples t-test confirmed that there were no significant differences between the training volumes for the PLA-HIIT and HMBFA-HIIT groups. Conclusions Our findings support the use of HIIT in combination with HMBFA to improve aerobic fitness in college age men and women. These data suggest that the addition of HMBFA supplementation may result in greater changes in VO2peak and VT than HIIT alone. Study registration The study was registered on ClinicalTrials.gov (ID NCT01941368). PMID:24782684

Polymorphisms in nitric oxide synthase and endothelin genes among children with obstructive sleep apnea.

PubMed

Chatsuriyawong, Siriporn; Gozal, David; Kheirandish-Gozal, Leila; Bhattacharjee, Rakesh; Khalyfa, Ahamed A; Wang, Yang; Sukhumsirichart, Wasana; Khalyfa, Abdelnaby

2013-09-06

Obstructive sleep apnea (OSA) is associated with adverse and interdependent cognitive and cardiovascular consequences. Increasing evidence suggests that nitric oxide synthase (NOS) and endothelin family (EDN) genes underlie mechanistic aspects of OSA-associated morbidities. We aimed to identify single nucleotide polymorphisms (SNPs) in the NOS family (3 isoforms), and EDN family (3 isoforms) to identify potential associations of these SNPs in children with OSA. A pediatric community cohort (ages 5-10 years) enriched for snoring underwent overnight polysomnographic (NPSG) and a fasting morning blood draw. The diagnostic criteria for OSA were an obstructive apnea-hypopnea Index (AHI) >2/h total sleep time (TST), snoring during the night, and a nadir oxyhemoglobin saturation <92%. Control children were defined as non-snoring children with AHI <2/h TST (NOSA). Endothelial function was assessed using a modified post-occlusive hyperemic test. The time to peak reperfusion (Tmax) was considered as the indicator for normal endothelial function (NEF; Tmax<45 sec), or ED (Tmax ≥ 45 sec). Genomic DNA from peripheral blood was extracted and allelic frequencies were assessed for, NOS1 (209 SNPs), NOS2 (122 SNPs), NOS3 (50 SNPs), EDN1 (43 SNPs), EDN2 (48 SNPs), EDN3 (14 SNPs), endothelin receptor A, EDNRA, (27 SNPs), and endothelin receptor B, EDNRB (23 SNPs) using a custom SNPs array. The relative frequencies of NOS-1,-2, and -3, and EDN-1,-2,-3,-EDNRA, and-EDNRB genotypes were evaluated in 608 subjects [128 with OSA, and 480 without OSA (NOSA)]. Furthermore, subjects with OSA were divided into 2 subgroups: OSA with normal endothelial function (OSA-NEF), and OSA with endothelial dysfunction (OSA-ED). Linkage disequilibrium was analyzed using Haploview version 4.2 software. For NOSA vs. OSA groups, 15 differentially distributed SNPs for NOS1 gene, and 1 SNP for NOS3 emerged, while 4 SNPs for EDN1 and 1 SNP for both EDN2 and EDN3 were identified. However, in the smaller sub-group for whom endothelial function was available, none of the significant SNPs was retained due to lack of statistical power. Differences in the distribution of polymorphisms among NOS and EDN gene families suggest that these SNPs could play a contributory role in the pathophysiology and risk of OSA-induced cardiovascular morbidity. Thus, analysis of genotype-phenotype interactions in children with OSA may assist in the formulation of categorical risk estimates.

The relationship between surface temperature, tissue temperature, microbubble formation, and steam pops.

PubMed

Thompson, Nathaniel; Lustgarten, Daniel; Mason, Bryan; Mueller, Enkhtuyaa; Calame, James; Bell, Stephen; Spector, Peter

2009-07-01

It has been proposed that microbubble (MB) monitoring can be used to safely titrate radiofrequency (RF) power. However, MB formation has been found to be an insensitive indicator of tissue temperature during RF delivery. We hypothesized that MB formation corresponds to surface-not tissue--temperature, and therefore would be an insensitive predictor of steam pops. An in vitro bovine heart model was used to measure surface and tissue temperatures during RF delivery under conditions designed to cause steam pops. Sensitivity of type II MB (MBII) formation as a predictor of steam pops and for surface temperatures more than 80 degrees C was calculated. Of 105 lesions delivered, 99 steam pops occurred. Twenty-one steam pops were preceded by MBII. MBII were seen in 26 lesions, five of which were not associated with steam pop. Surface temperature at onset of MBII was 87 +/- 9 degrees C versus a tissue temperature of 78 +/- 23 degrees C (P = 0.044). Surface temperature at the time of steam pops was 71 +/- 17 degrees C versus a tissue temperature of 102 +/- 17 degrees C (P < 0.0001). The sensitivity of MBII for steam pops was 21%, and 58% for detecting surface temperature in excess of 80 degrees C. MBII correlated better with surface temperature than with tissue temperature; steam pops, on the other hand, correlated better with tissue temperature. MBII was an insensitive marker of steam pops and surface temperature in excess of 80 degrees C. Therefore, MBII should not be used to titrate RF power.

Active radiometer for self-calibrated furnace temperature measurements

DOEpatents

Woskov, Paul P.; Cohn, Daniel R.; Titus, Charles H.; Wittle, J. Kenneth; Surma, Jeffrey E.

1996-01-01

Radiometer with a probe beam superimposed on its field-of-view for furnace temperature measurements. The radiometer includes a heterodyne millimeter/submillimeter-wave receiver including a millimeter/submillimeter-wave source for probing. The receiver is adapted to receive radiation from a surface whose temperature is to be measured. The radiation includes a surface emission portion and a surface reflection portion which includes the probe beam energy reflected from the surface. The surface emission portion is related to the surface temperature and the surface reflection portion is related to the emissivity of the surface. The simultaneous measurement of surface emissivity serves as a real time calibration of the temperature measurement.

Assimilation of Surface Temperature in Land Surface Models

NASA Technical Reports Server (NTRS)

Lakshmi, Venkataraman

1998-01-01

Hydrological models have been calibrated and validated using catchment streamflows. However, using a point measurement does not guarantee correct spatial distribution of model computed heat fluxes, soil moisture and surface temperatures. With the advent of satellites in the late 70s, surface temperature is being measured two to four times a day from various satellite sensors and different platforms. The purpose of this paper is to demonstrate use of satellite surface temperature in (a) validation of model computed surface temperatures and (b) assimilation of satellite surface temperatures into a hydrological model in order to improve the prediction accuracy of soil moistures and heat fluxes. The assimilation is carried out by comparing the satellite and the model produced surface temperatures and setting the "true"temperature midway between the two values. Based on this "true" surface temperature, the physical relationships of water and energy balance are used to reset the other variables. This is a case of nudging the water and energy balance variables so that they are consistent with each other and the true" surface temperature. The potential of this assimilation scheme is demonstrated in the form of various experiments that highlight the various aspects. This study is carried over the Red-Arkansas basin in the southern United States (a 5 deg X 10 deg area) over a time period of a year (August 1987 - July 1988). The land surface hydrological model is run on an hourly time step. The results show that satellite surface temperature assimilation improves the accuracy of the computed surface soil moisture remarkably.

Temperature measurement involving nanostructured thermal barrier coating using a multiwavelength pyrometer

NASA Technical Reports Server (NTRS)

Ng, Daniel

1996-01-01

It has been reported that erroneous results were obtained when a conventional pyrometer was used to measure the surface temperature of turbine engine components. Temperatures discrepancies were observed in components which were identical, except that one had its measured surface covered by a nanostructured thermal barrier coating (TBC) whereas the other component's surface was not so coated. These components were placed in an identical environment, receiving identical heat fluxes. A pyrometer measured the TBC covered surface hundreds degrees lower. These coatings were about 25 (mu)m thick, consisting of hundreds of layers of finer structures. The TBC's had very low thermal conductivity, heat flux calculations indicated that the temperatures of the coated surface should exhibit much higher temperature than the uncoated surface. Because these coatings were transparent to radiation from the visible to the infrared region, the temperatures measured by the pyrometer should be the temperature of the covered surface. Turbo components' performance and service life depend critically on the temperatures that it would experience; it is therefore important to know accurately and confidently the real surface temperature. Out of these concerns, an investigation into the measurement of nanostructured material surface temperature was carried out.

Estimation of Surface Heat Flux and Surface Temperature during Inverse Heat Conduction under Varying Spray Parameters and Sample Initial Temperature

PubMed Central

Aamir, Muhammad; Liao, Qiang; Zhu, Xun; Aqeel-ur-Rehman; Wang, Hong

2014-01-01

An experimental study was carried out to investigate the effects of inlet pressure, sample thickness, initial sample temperature, and temperature sensor location on the surface heat flux, surface temperature, and surface ultrafast cooling rate using stainless steel samples of diameter 27 mm and thickness (mm) 8.5, 13, 17.5, and 22, respectively. Inlet pressure was varied from 0.2 MPa to 1.8 MPa, while sample initial temperature varied from 600°C to 900°C. Beck's sequential function specification method was utilized to estimate surface heat flux and surface temperature. Inlet pressure has a positive effect on surface heat flux (SHF) within a critical value of pressure. Thickness of the sample affects the maximum achieved SHF negatively. Surface heat flux as high as 0.4024 MW/m2 was estimated for a thickness of 8.5 mm. Insulation effects of vapor film become apparent in the sample initial temperature range of 900°C causing reduction in surface heat flux and cooling rate of the sample. A sensor location near to quenched surface is found to be a better choice to visualize the effects of spray parameters on surface heat flux and surface temperature. Cooling rate showed a profound increase for an inlet pressure of 0.8 MPa. PMID:24977219

Prediction of climate change in Brunei Darussalam using statistical downscaling model

NASA Astrophysics Data System (ADS)

Hasan, Dk. Siti Nurul Ain binti Pg. Ali; Ratnayake, Uditha; Shams, Shahriar; Nayan, Zuliana Binti Hj; Rahman, Ena Kartina Abdul

2017-06-01

Climate is changing and evidence suggests that the impact of climate change would influence our everyday lives, including agriculture, built environment, energy management, food security and water resources. Brunei Darussalam located within the heart of Borneo will be affected both in terms of precipitation and temperature. Therefore, it is crucial to comprehend and assess how important climate indicators like temperature and precipitation are expected to vary in the future in order to minimise its impact. This study assesses the application of a statistical downscaling model (SDSM) for downscaling General Circulation Model (GCM) results for maximum and minimum temperatures along with precipitation in Brunei Darussalam. It investigates future climate changes based on numerous scenarios using Hadley Centre Coupled Model, version 3 (HadCM3), Canadian Earth System Model (CanESM2) and third-generation Coupled Global Climate Model (CGCM3) outputs. The SDSM outputs were improved with the implementation of bias correction and also using a monthly sub-model instead of an annual sub-model. The outcomes of this assessment show that monthly sub-model performed better than the annual sub-model. This study indicates a satisfactory applicability for generation of maximum temperatures, minimum temperatures and precipitation for future periods of 2017-2046 and 2047-2076. All considered models and the scenarios were consistent in predicting increasing trend of maximum temperature, increasing trend of minimum temperature and decreasing trend of precipitations. Maximum overall trend of Tmax was also observed for CanESM2 with Representative Concentration Pathways (RCP) 8.5 scenario. The increasing trend is 0.014 °C per year. Accordingly, by 2076, the highest prediction of average maximum temperatures is that it will increase by 1.4 °C. The same model predicts an increasing trend of Tmin of 0.004 °C per year, while the highest trend is seen under CGCM3-A2 scenario which is 0.009 °C per year. The highest change predicted for the Tmin is therefore 0.9 °C by 2076. The precipitation showed a maximum trend of decrease of 12.7 mm year. It is also seen in the output using CanESM2 data that precipitation will be more chaotic with some reaching 4800 mm per year and also producing low rainfall about 1800 mm per year. All GCMs considered are consistent in predicting it is very likely that Brunei is expected to experience more warming as well as less frequent precipitation events but with a possibility of intensified and drastically high rainfalls in the future.

Do Aphids Alter Leaf Surface Temperature Patterns During Early Infestation?

PubMed Central

Cahon, Thomas; Caillon, Robin

2018-01-01

Arthropods at the surface of plants live in particular microclimatic conditions that can differ from atmospheric conditions. The temperature of plant leaves can deviate from air temperature, and leaf temperature influences the eco-physiology of small insects. The activity of insects feeding on leaf tissues, may, however, induce changes in leaf surface temperatures, but this effect was only rarely demonstrated. Using thermography analysis of leaf surfaces under controlled environmental conditions, we quantified the impact of presence of apple green aphids on the temperature distribution of apple leaves during early infestation. Aphids induced a slight change in leaf surface temperature patterns after only three days of infestation, mostly due to the effect of aphids on the maximal temperature that can be found at the leaf surface. Aphids may induce stomatal closure, leading to a lower transpiration rate. This effect was local since aphids modified the configuration of the temperature distribution over leaf surfaces. Aphids were positioned at temperatures near the maximal leaf surface temperatures, thus potentially experiencing the thermal changes. The feedback effect of feeding activity by insects on their host plant can be important and should be quantified to better predict the response of phytophagous insects to environmental changes. PMID:29538342

An investigation of the safety and pharmacokinetics of the novel TRPV1 antagonist XEN-D0501 in healthy subjects

PubMed Central

Round, Patrick; Priestley, Anthony; Robinson, Jan

2011-01-01

AIMS XEN-D0501, a novel TRPV1 antagonist, is being developed to treat overactive bladder. This study investigated the safety and pharmacokinetics of repeat-dose XEN-D0501 in healthy subjects. METHODS The study was conducted in two parts. Part 1 was a double-blind, randomized, placebo-controlled, two-way crossover study in three cohorts of 12 young male subjects. Each subject received XEN-D0501 and placebo (in random order) twice daily for 13 days, with a final single dose on day 14. Doses of 1, 2.5 and 5 mg XEN-D0501 were investigated. Part 2 was an open-label, randomized, two-way crossover study in male and female subjects (45 to 65 years). Subjects received single doses of 5 mg XEN-D0501 under fasted and fed conditions in random order. Blood sampling and safety assessments were conducted throughout the study. RESULTS XEN-D0501 was rapidly absorbed (tmax generally 0.5–4 h post dose). XEN-D0501 exposure increased less than proportionally to dose over the range studied and exhibited minimal accumulation with twice daily dosing. Food had no clinically relevant effects on the pharmacokinetics of XEN-D0501. There were no severe or serious adverse events and all doses were well tolerated. A dose-related increase in body temperature was seen with XEN-D0501 which attenuated over time. Differences from placebo in mean maximum core body temperatures were 0.22°C, 0.5°C and 0.74°C following 1 mg, 2.5 mg and 5 mg twice daily XEN-D0501. The observed increase in body temperature was not considered to be of clinical concern. CONCLUSIONS XEN-D0501 appeared safe and well tolerated at doses up to 5 mg twice daily for 14 days in healthy subjects. PMID:21676011

Areas of Weakly Anomalous to Anomalous Surface Temperature in Chaffee County, Colorado, as Identified from ASTER Thermal Data

DOE Data Explorer

Khalid Hussein

2012-02-01

Note: This "Weakly Anomalous to Anomalous Surface Temperature" dataset differs from the "Anomalous Surface Temperature" dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1o and 2o above the mean, as opposed to the greater than 2o temperatures contained in the "Anomalous Surface Temperature" dataset. This layer contains areas of anomalous surface temperature in Chaffee County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2o were considered ASTER modeled very warm surface exposures (thermal anomalies). Note: 'o' is used in this description to represent lowercase sigma.

Areas of Weakly Anomalous to Anomalous Surface Temperature in Garfield County, Colorado, as Identified from ASTER Thermal Data

DOE Data Explorer

Khalid Hussein

2012-02-01

Note: This "Weakly Anomalous to Anomalous Surface Temperature" dataset differs from the "Anomalous Surface Temperature" dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1o and 2o above the mean, as opposed to the greater than 2o temperatures contained in the "Anomalous Surface Temperature" dataset. This layer contains areas of anomalous surface temperature in Garfield County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1o and 2o were considered ASTER modeled warm surface exposures (thermal anomalies) Note: 'o' is used in this description to represent lowercase sigma.

Areas of Weakly Anomalous to Anomalous Surface Temperature in Routt County, Colorado, as Identified from ASTER Thermal Data

DOE Data Explorer

Khalid Hussein

2012-02-01

Note: This "Weakly Anomalous to Anomalous Surface Temperature" dataset differs from the "Anomalous Surface Temperature" dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1o and 2o above the mean, as opposed to the greater than 2o temperatures contained in the "Anomalous Surface Temperature" dataset. This layer contains areas of anomalous surface temperature in Routt County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1o and 2o were considered ASTER modeled warm surface exposures (thermal anomalies). Note: 'o' is used in this description to represent lowercase sigma.

Areas of Weakly Anomalous to Anomalous Surface Temperature in Dolores County, Colorado, as Identified from ASTER Thermal Data

DOE Data Explorer

Khalid Hussein

2012-02-01

Note: This "Weakly Anomalous to Anomalous Surface Temperature" dataset differs from the "Anomalous Surface Temperature" dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1o and 2o above the mean, as opposed to the greater than 2o temperatures contained in the "Anomalous Surface Temperature" dataset. This layer contains areas of anomalous surface temperature in Dolores County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature greater than 2o were considered ASTER modeled very warm surface exposures (thermal anomalies) Note: 'o' is used in this description to represent lowercase sigma.

Areas of Weakly Anomalous to Anomalous Surface Temperature in Archuleta County, Colorado, as Identified from ASTER Thermal Data

DOE Data Explorer

Khalid Hussein

2012-02-01

Note: This "Weakly Anomalous to Anomalous Surface Temperature" dataset differs from the "Anomalous Surface Temperature" dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1o and 2o above the mean, as opposed to the greater than 2o temperatures contained in the "Anomalous Surface Temperature" dataset. This layer contains areas of anomalous surface temperature in Archuleta County identified from ASTER thermal data and spatial based insolation model. The temperature is calculated using the Emissivity Normalization Algorithm that separate temperature from emissivity. The incoming solar radiation was calculated using spatial based insolation model developed by Fu and Rich (1999). Then the temperature due to solar radiation was calculated using emissivity derived from ASTER data. The residual temperature, i.e. temperature due to solar radiation subtracted from ASTER temperature was used to identify thermally anomalous areas. Areas that had temperature between 1o and 2o were considered ASTER modeled warm surface exposures (thermal anomalies). Note: 'o' is used in this description to represent lowercase sigma.

Active radiometer for self-calibrated furnace temperature measurements

DOEpatents

Woskov, P.P.; Cohn, D.R.; Titus, C.H.; Wittle, J.K.; Surma, J.E.

1996-11-12

A radiometer is described with a probe beam superimposed on its field-of-view for furnace temperature measurements. The radiometer includes a heterodyne millimeter/submillimeter-wave receiver including a millimeter/submillimeter-wave source for probing. The receiver is adapted to receive radiation from a surface whose temperature is to be measured. The radiation includes a surface emission portion and a surface reflection portion which includes the probe beam energy reflected from the surface. The surface emission portion is related to the surface temperature and the surface reflection portion is related to the emissivity of the surface. The simultaneous measurement of surface emissivity serves as a real time calibration of the temperature measurement. 5 figs.

Heterogeneity of soil surface temperature induced by xerophytic shrub in a revegetated desert ecosystem, northwestern China

NASA Astrophysics Data System (ADS)

Zhang, Ya-Feng; Wang, Xin-Ping; Pan, Yan-Xia; Hu, Rui; Zhang, Hao

2013-06-01

Variation characteristics of the soil surface temperature induced by shrub canopy greatly affects the near-surface biological and biochemical processes in desert ecosystems. However, information regarding the effects of shrub upon the heterogeneity of soil surface temperature is scarce. Here we aimed to characterize the effects of shrub ( Caragana korshinskii) canopy on the soil surface temperature heterogeneity at areas under shrub canopy and the neighbouring bare ground. Diurnal variations of soil surface temperature were measured at areas adjacent to the shrub base (ASB), beneath the midcanopy (BMC), and in the bare intershrub spaces (BIS) at the eastern, southern, western and northern aspects of shrub, respectively. Results indicated that diurnal mean soil surface temperature under the C. korshinskii canopy (ASB and BMC) was significantly lower than in the BIS, with the highest in the BIS, followed by the BMC and ASB. The diurnal maximum and diurnal variations of soil surface temperatures under canopy vary strongly with different aspects of shrub with the diurnal variation in solar altitude, which could be used as cues to detect safe sites for under-canopy biota. A significant empirical linear relationship was found between soil surface temperature and solar altitude, suggesting an empirical predicator that solar altitude can serve for soil surface temperature. Lower soil surface temperatures under the canopy than in the bare intershrub spaces imply that shrubs canopy play a role of `cool islands' in the daytime in terms of soil surface temperature during hot summer months in the desert ecosystems characterized by a mosaic of sparse vegetation and bare ground.

Preliminary study of temperature measurement techniques for Stirling engine reciprocating seals

NASA Technical Reports Server (NTRS)

Wilcock, D. F.; Hoogenboom, L.; Meinders, M.; Winer, W. O.

1981-01-01

Methods of determining the contact surface temperature in reciprocating seals are investigated. Direct infrared measurement of surface temperatures of a rod exiting a loaded cap seal or simulated seal are compared with surface thermocouple measurements. Significant cooling of the surface requires several milliseconds so that exit temperatures may be considered representative of internal contact temperatures.

Comparison between AVHRR surface temperature data and in-situ weather station temperatures over the Greenland Ice Sheet

NASA Astrophysics Data System (ADS)

Rezvanbehbahani, S.; Csatho, B. M.; Comiso, J. C.; Babonis, G. S.

2011-12-01

Advanced Very-High Resolution Radiometer (AVHRR) images have been exhaustively used to measure surface temperature time series of the Greenland Ice sheet. The purpose of this study is to assess the accuracy of monthly average ice sheet surface temperatures, derived from thermal infrared AVHRR satellite imagery on a 6.25 km grid. In-situ temperature data sets are from the Greenland Collection Network (GC-Net). GC-Net stations comprise sensors monitoring air temperature at 1 and 2 meter above the snow surface, gathered at every 60 seconds and monthly averaged to match the AVHRR temporal resolution. Our preliminary results confirm the good agreement between satellite and in-situ temperature measurements reported by previous studies. However, some large discrepancies still exist. While AVHRR provides ice surface temperature, in-situ stations measure air temperatures at different elevations above the snow surface. Since most in-situ data on ice sheets are collected by Automatic Weather Station (AWS) instruments, it is important to characterize the difference between surface and air temperatures. Therefore, we compared and analyzed average monthly AVHRR ice surface temperatures using data collected in 2002. Differences between these temperatures correlate with in-situ temperatures and GC-Net station elevations, with increasing differences at lower elevations and higher temperatures. The Summit Station (3199 m above sea level) and the Swiss Camp (1176 m above sea level) results were compared as high altitude and low altitude stations for 2002, respectively. Our results show that AVHRR derived temperatures were 0.5°K warmer than AWS temperature at the Summit Station, while this difference was 2.8°K in the opposite direction for the Swiss Camp with surface temperatures being lower than air temperatures. The positive bias of 0.5°K at the high altitude Summit Station (surface warmer than air) is within the retrieval error of AVHRR temperatures and might be in part due to atmospheric inversion. The large negative bias of 2.8°K at the low altitude Swiss Camp (surface colder than the air) could be caused by a combination of different factors including local effects such as more windy circumstances above the snow surface and biases introduced by the cloud-masking applied on the AVHRR images. Usually only satellite images acquired in clear-sky conditions are used for deriving monthly AVHRR average temperatures. Since cloud-free days are usually warmer, satellite derived temperatures tend to underestimate the real average temperatures, especially regions with frequent cloud cover, such as Swiss Camp. Therefore, cautions must be exercised while using ice surface temperatures derived from satellite imagery for glaciological applications. Eliminating the cloudy day's' temperature from the in-situ data prior to the comparison with AVHRR derived temperatures will provide a better assessment of AVHRR surface temperature measurement accuracy.

Estimating the Longwave Radiation Underneath the Forest Canopy in Snow-dominated Setting

NASA Astrophysics Data System (ADS)

Zhou, Y.; Kumar, M.; Link, T. E.

2017-12-01

Forest canopies alter incoming longwave radiation at the land surface, thus influencing snow cover energetics. The snow surface receives longwave radiation from the sky as well as from surrounding vegetation. The longwave radiation from trees is determined by its skin temperature, which shows significant heterogeneity depending on its position and morphometric attributes. Here our goal is to derive an effective tree temperature that can be used to estimate the longwave radiation received by the land surface pixel. To this end, we implement these three steps: 1) derive a relation between tree trunk surface temperature and the incident longwave radiation, shortwave radiation, and air temperature; 2) develop an inverse model to calculate the effective temperature by establishing a relationship between the effective temperature and the actual tree temperature; and 3) estimate the effective temperature using widely measured variables, such as solar radiation and forest density. Data used to derive aforementioned relations were obtained at the University of Idaho Experimental Forest, in northern Idaho. Tree skin temperature, incoming longwave radiation, solar radiation received by the tree surface, and air temperature were measured at an isolated tree and a tree within a homogeneous forest stand. Longwave radiation received by the land surface and the sky view factors were also measured at the same two locations. The calculated effective temperature was then compared with the measured tree trunk surface temperature. Additional longwave radiation measurements with pyrgeometer arrays were conducted under forests with different densities to evaluate the relationship between effective temperature and forest density. Our preliminary results show that when exposed to direct shortwave radiation, the tree surface temperature shows a significant difference from the air temperature. Under cloudy or shaded conditions, the tree surface temperature closely follows the air temperature. The effective tree temperature follows the air temperature in a dense forest stand, although it is significantly larger than the air temperature near the isolated tree. This discrepancy motivates us to explore ways to represent the effective tree temperature for stands with different densities.

Low temperature self-cleaning properties of superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Wang, Fajun; Shen, Taohua; Li, Changquan; Li, Wen; Yan, Guilong

2014-10-01

Outdoor surfaces are usually dirty surfaces. Ice accretion on outdoor surfaces could lead to serious accidents. In the present work, the superhydrophobic surface based on 1H, 1H, 2H, 2H-Perfluorodecanethiol (PFDT) modified Ag/PDMS composite was prepared to investigate the anti-icing property and self-cleaning property at temperatures below freezing point. The superhydrophobic surface was deliberately polluted with activated carbon before testing. It was observed that water droplet picked up dusts on the cold superhydrophobic surface and took it away without freezing at a measuring temperature of -10 °C. While on a smooth PFDT surface and a rough surface base on Ag/PDMS composite without PFDT modification, water droplets accumulated and then froze quickly at the same temperature. However, at even lower temperature of -12 °C, the superhydrophobic surface could not prevent the surface water from icing. In addition, it was observed that the frost layer condensed from the moisture pay an important role in determining the low temperature self-cleaning properties of a superhydrophobic surface.

Fuel Estimation Using Dynamic Response

DTIC Science & Technology

2007-03-01

T_min >G mag_min=T_min -G; end if T_max >G mag_max=T_max -G; 35 end % Deside which point in sorted data to get rid of if isempty(mag_min)+isempty...Wilber Lacy for all of the help he gave me getting SimSAT up and running. Without his help I would have never been able to finish. I would also like to...have become increasingly interested in determining precisely how much fuel remains in order to extend the life of the satellite as much as possible

Preparation and High-temperature Anti-adhesion Behavior of a Slippery Surface on Stainless Steel.

PubMed

Zhang, Pengfei; Huawei, Chen; Liu, Guang; Zhang, Liwen; Zhang, Deyuan

2018-03-29

Anti-adhesion surfaces with high-temperature resistance have a wide application potential in electrosurgical instruments, engines, and pipelines. A typical anti-wetting superhydrophobic surface easily fails when exposed to a high-temperature liquid. Recently, Nepenthes-inspired slippery surfaces demonstrated a new way to solve the adhesion problem. A lubricant layer on the slippery surface can act as a barrier between the repelled materials and the surface structure. However, the slippery surfaces in previous studies rarely showed high-temperature resistance. Here, we describe a protocol for the preparation of slippery surfaces with high-temperature resistance. A photolithography-assisted method was used to fabricate pillar structures on stainless steel. By functionalizing the surface with saline, a slippery surface was prepared by adding silicone oil. The prepared slippery surface maintained the anti-wetting property for water, even when the surface was heated to 300 °C. Also, the slippery surface exhibited great anti-adhesion effects on soft tissues at high temperatures. This type of slippery surface on stainless steel has applications in medical devices, mechanical equipment, etc.

Permian paleoclimate data from fluid inclusions in halite

USGS Publications Warehouse

Benison, K.C.; Goldstein, R.H.

1999-01-01

This study has yielded surface water paleotemperatures from primary fluid inclusions in mid Permian Nippewalla Group halite from western Kansas. A 'cooling nucleation' method is used to generate vapor bubbles in originally all-liquid primary inclusions. Then, surface water paleotemperatures are obtained by measuring temperatures of homogenization to liquid. Homogenization temperatures ranged from 21??C to 50??C and are consistent along individual fluid inclusion assemblages, indicating that the fluid inclusions have not been altered by thermal reequilibration. Homogenization temperatures show a range of up to 26??C from base to top of individual cloudy chevron growth bands. Petrographic and fluid inclusion evidence indicate that no significant pressure correction is needed for the homogenization temperature data. We interpret these homogenization temperatures to represent shallow surface water paleotemperatures. The range in temperatures from base to top of single chevron bands may reflect daily temperatures variations. These Permian surface water temperatures fall within the same range as some modern evaporative surface waters, suggesting that this Permian environment may have been relatively similar to its modern counterparts. Shallow surface water temperatures in evaporative settings correspond closely to local air temperatures. Therefore, the Permian surface water temperatures determined in this study may be considered proxies for local Permian air temperatures.

Temperature-dependent surface density of alkylthiol monolayers on gold nanocrystals

NASA Astrophysics Data System (ADS)

Liu, Xuepeng; Lu, Pin; Zhai, Hua; Wu, Yucheng

2018-03-01

Atomistic molecular dynamics (MD) simulations are performed to study the surface density of passivating monolayers of alkylthiol chains on gold nanocrystals at temperatures ranging from 1 to 800 K. The results show that the surface density of alkylthiol monolayer reaches a maximum value at near room temperature (200-300 K), while significantly decreases with increasing temperature in the higher temperature region (> 300 {{K}}), and slightly decreases with decreasing temperature at low temperature (< 200 {{K}}). We find that the temperature dependence of surface ligand density in the higher temperature region is attributed to the substantial ligand desorption induced by the thermal fluctuation, while that at low temperature results from the reduction in entropy caused by the change in the ordering of passivating monolayer. These results are expected helpful to understand the temperature-dependent surface coverage of gold nanocrystals.

Estimation of subsurface thermal structure using sea surface height and sea surface temperature

NASA Technical Reports Server (NTRS)

Kang, Yong Q. (Inventor); Jo, Young-Heon (Inventor); Yan, Xiao-Hai (Inventor)

2012-01-01

A method of determining a subsurface temperature in a body of water is disclosed. The method includes obtaining surface temperature anomaly data and surface height anomaly data of the body of water for a region of interest, and also obtaining subsurface temperature anomaly data for the region of interest at a plurality of depths. The method further includes regressing the obtained surface temperature anomaly data and surface height anomaly data for the region of interest with the obtained subsurface temperature anomaly data for the plurality of depths to generate regression coefficients, estimating a subsurface temperature at one or more other depths for the region of interest based on the generated regression coefficients and outputting the estimated subsurface temperature at the one or more other depths. Using the estimated subsurface temperature, signal propagation times and trajectories of marine life in the body of water are determined.

Diffusion bonding

DOEpatents

Anderson, Robert C.

1976-06-22

1. A method for joining beryllium to beryllium by diffusion bonding, comprising the steps of coating at least one surface portion of at least two beryllium pieces with nickel, positioning a coated surface portion in a contiguous relationship with an other surface portion, subjecting the contiguously disposed surface portions to an environment having an atmosphere at a pressure lower than ambient pressure, applying a force upon the beryllium pieces for causing the contiguous surface portions to abut against each other, heating the contiguous surface portions to a maximum temperature less than the melting temperature of the beryllium, substantially uniformly decreasing the applied force while increasing the temperature after attaining a temperature substantially above room temperature, and maintaining a portion of the applied force at a temperature corresponding to about maximum temperature for a duration sufficient to effect the diffusion bond between the contiguous surface portions.

Dynamic, Hot Surface Ignition of Aircraft Fuels and Hydraulic Fluids

DTIC Science & Technology

1980-10-01

fuels on a heated stainless steel surface. Higher local surface air speeds necessitated higher surface temperatures for ignition of an applied fluid._-7...Aircraft Fuels ( stainless steel surface) 8. Air Speed and Surface Material Effects on Hot Surface 21 Ignition Temperature of Aircraft Fuels (Titanium...Material Effects on Hot Surface 26 Ignition Temperature of Aircraft Hydraulic Fluids ( Stainless steel surface) 11. Air Speed and Surface Material

Thermoluminescence of quartz collected from Nojima Fault Trench excavated in 2015

NASA Astrophysics Data System (ADS)

Hasebe, N.; Miura, K.; Ganzawa, Y.; Tagami, T.; Lin, A.

2017-12-01

The Southern Hyogo prefecture earthquake occurred in 1995, which is known as Kobe Earthquake or Great Hanshin-Awaji Earthquake, was caused by the activity of the Nojima fault.　The research project on the Nojima fault is currently going on and new trench was excavated in 2015. We investigate the effect of fault activity on surrounding rocks by thermoluminescence (TL) dating method. First, quartz were extracted from samples collected from the trench wall with different distance from the fault. A block of nearby basement rock is also collected and analyzed. Next, the luminescence sites and their emission temperatures were determined by T-Tmax method (McKeever, 1980) perfomed by 10 ° C interval for selected samples (the basement rock collected from Rokko granite, the granite sample collected about 5 m away from the fault in the trench, and the gouge sample adjacent to the fault). As a result, the peak emission temperatures were 200-220 ° C, 270 ° C and 320-350 ° C for granite quartz. These values were concordant for UV-TL and Blue TL. The activation energy and frequency factors were determined for signals emitted at different temperatures by peak shift methods (Aitken, 1985). On the other hand, the TL emission curves for the sample adjacent to the fault do not show discrete luminescence sites, different from granite samples. Natural TL emission show variety of TL profile. The accumulated doses of each sample were estimated for identified signal peaks after peak separation. Signals from different peak temperatures show different dose values in all the samples. The dose estimated by signals at 200 ° showed the minimum value for all samples. The same sample show different accumulated dose for Blue TL and UV-TL. The variety of accumulated doses in a sample may be reflective of complex thermal history of samples, and/or partly caused by the ineffective peak separation. Even the host rock collected away from the fault show a low accumulated dose in 200°C singnal, far less than the expected saturated value. Further investigation is important to fully understand the meaning of obtained data.

Near Surface Thermal Stratification during Summer at Summit, Greenland, and its Impact on MODIS-derived Surface Temperatures

NASA Astrophysics Data System (ADS)

Adolph, A. C.; Albert, M. R.; Hall, D. K.

2017-12-01

As rapid warming of the Arctic occurs, it is imperative that we monitor climate parameters such as temperature over large areas to understand and predict the extent of climate changes. Temperatures are often tracked using in-situ 2 m air temperatures, but in remote locations such as on the Greenland Ice Sheet, temperature can be studied more comprehensively using remote sensing techniques. Because of the presence of surface-based temperature inversions in ice-covered areas, differences between 2 m air temperature and skin temperature can be significant and are particularly relevant when considering validation and application of remote sensing temperature data. We present results from a field campaign at Summit Station in Greenland to study surface temperature using the following measurements: skin temperature measured by IR sensors, thermochrons, and thermocouples; 2 m air temperature measured by a NOAA meteorological station; and two different MODerate-resolution Imaging Spectroradiometer (MODIS) surface temperature products. We confirm prior findings that in-situ 2 m air temperature is often significantly higher in the summer than in-situ skin temperature when incoming solar radiation and wind speed are low. This inversion may account for biases in previous MODIS surface temperature studies that used 2 m air temperature for validation. As compared to the in-situ IR skin temperature measurements, the MOD/MYD11 Collection 6 surface-temperature standard product has an RMSE of 1.0°C, and that the MOD29 Collection 6 product has an RMSE of 1.5°C, spanning a range of temperatures from -35°C to -5°C. For our study area and time series, MODIS surface temperature products agree with skin temperatures better than many previous studies have indicated, especially at temperatures below -20°C where other studies found a significant cold bias. Further investigation at temperatures below -35°C is warranted to determine if this bias does indeed exist.

High-frequency fluctuations of surface temperatures in an urban environment

NASA Astrophysics Data System (ADS)

Christen, Andreas; Meier, Fred; Scherer, Dieter

2012-04-01

This study presents an attempt to resolve fluctuations in surface temperatures at scales of a few seconds to several minutes using time-sequential thermography (TST) from a ground-based platform. A scheme is presented to decompose a TST dataset into fluctuating, high-frequency, and long-term mean parts. To demonstrate the scheme's application, a set of four TST runs (day/night, leaves-on/leaves-off) recorded from a 125-m-high platform above a complex urban environment in Berlin, Germany is used. Fluctuations in surface temperatures of different urban facets are measured and related to surface properties (material and form) and possible error sources. A number of relationships were found: (1) Surfaces with surface temperatures that were significantly different from air temperature experienced the highest fluctuations. (2) With increasing surface temperature above (below) air temperature, surface temperature fluctuations experienced a stronger negative (positive) skewness. (3) Surface materials with lower thermal admittance (lawns, leaves) showed higher fluctuations than surfaces with high thermal admittance (walls, roads). (4) Surface temperatures of emerged leaves fluctuate more compared to trees in a leaves-off situation. (5) In many cases, observed fluctuations were coherent across several neighboring pixels. The evidence from (1) to (5) suggests that atmospheric turbulence is a significant contributor to fluctuations. The study underlines the potential of using high-frequency thermal remote sensing in energy balance and turbulence studies at complex land-atmosphere interfaces.

Comparing AIRS/AMSU-A Satellite and MERRA/MERRA-2 Reanalysis products with In-situ Station Observations at Summit, Greenland

NASA Astrophysics Data System (ADS)

Hearty, T. J., III; Vollmer, B.; Wei, J. C.; Huwe, P. M.; Albayrak, A.; Wu, D. L.; Cullather, R. I.; Meyer, D. L.; Lee, J. N.; Blaisdell, J. M.; Susskind, J.; Nowicki, S.

2017-12-01

The surface air and skin temperatures reported by the Atmospheric Infrared Sounder (AIRS), the Modern-Era Retrospective analysis for Research and Applications (MERRA), and MERRA-2 at Summit, Greenland are compared with near surface air temperatures measured at National Oceanic and Atmospheric Administration (NOAA) and Greenland Climate Network (GC-Net) weather stations. Therefore this investigation requires familiarity with a heterogeneous set of swath, grid, and point data in several different formats, different granularity, and different sampling. We discuss the current subsetting capabilities available at the GES DISC (Goddard Earth Sciences Data Information Services Center) to perform the inter-comparisons necessary to evaluate the quality and trustworthiness of these datasets. We also explore potential future services which may assist users with this type of intercomparison. We find the AIRS Surface Skin Temperature (TS) is best correlated with the NOAA 2 m air temperature (T2M) but it tends to be colder than the station measurements. The difference may be the result of the frequent near surface temperature inversions in the region. The AIRS Surface Air Temperature (SAT) is also well correlated with the NOAA T2M but it has a warm bias with respect to the NOAA T2M during the cold season and a larger standard error than surface temperature. This suggests that the extrapolation of the temperature profile to the surface is not valid for the strongest inversions. Comparing the temperature lapse rate derived from the 2 stations shows that the lapse rate can increase closer to the surface. We also find that the difference between the AIRS SAT and TS is sensitive to near surface inversions. The MERRA-2 surface and near surface temperatures show improvements over MERRA but little sensitivity to near surface temperature inversions.

Nonlinear dynamic model of a gear-rotor-bearing system considering the flash temperature

NASA Astrophysics Data System (ADS)

Gou, Xiangfeng; Zhu, Lingyun; Qi, Changjun

2017-12-01

The instantaneous flash temperature is an important factor for gears in service. To investigate the effect of the flash temperature of a tooth surface on the dynamics of the spur gear system, a modified nonlinear dynamic model of a gear-rotor-bearing system is established. The factors such as the contact temperature of the tooth surface, time-varying stiffness, tooth surface friction, backlash, the comprehensive transmission error and so on are considered. The flash temperature of a tooth surface of pinion and gear is formulated according to Blok's flash temperature theory. The mathematical expression of the contact temperature of the tooth surface varied with time is derived and the tooth profile deformation caused by the change of the flash temperature of the tooth surface is calculated. The expression of the mesh stiffness varied with the flash temperature of the tooth surface is derived based on Hertz contact theory. The temperature stiffness is proposed and added to the nonlinear dynamic model of the system. The influence of load on the flash temperature of the tooth surface is analyzed in the parameters plane. The variation of the flash temperature of the tooth surface is studied. The numerical results indicate that the calculated method of the flash temperature of the gear tooth surface is effective and it can reflect the rules for the change of gear meshing temperature and sliding of the gear tooth surface. The effects of frequency, backlash, bearing clearance, comprehensive transmission error and time-varying stiffness on the nonlinear dynamics of the system are analyzed according to the bifurcation diagrams, Top Lyapunov Exponent (TLE) spectrums, phase portraits and Poincaré maps. Some nonlinear phenomena such as periodic bifurcation, grazing bifurcation, quasi-periodic bifurcation, chaos and its routes to chaos are investigated and the critical parameters are identified. The results provide an understanding of the system and serve as a useful reference in designing such systems.

Effect of particle size on oral absorption of carvedilol nanosuspensions: in vitro and in vivo evaluation

PubMed Central

Liu, Dandan; Pan, Hao; He, Fengwei; Wang, Xiaoyu; Li, Jinyu; Yang, Xinggang; Pan, Weisan

2015-01-01

The purpose of this work was to explore the particle size reduction effect of carvedilol on dissolution and absorption. Three suspensions containing different sized particles were prepared by antisolvent precipitation method or in combination with an ultrasonication process. The suspensions were characterized for particle size, surface morphology, and crystalline state. The crystalline form of carvedilol was changed into amorphous form after antisolvent precipitation. The dissolution rate of carvedilol was significantly accelerated by a reduction in particle size. The intestinal absorption of carvedilol nanosuspensions was greatly improved in comparison with microsuspensions and solution in the in situ single-pass perfusion experiment. The in vivo evaluation demonstrated that carvedilol nanosuspensions and microsuspensions exhibited markedly increased Cmax (2.09- and 1.48-fold) and AUC0−t (2.11- and 1.51-fold), and decreased Tmax (0.34- and 0.48-fold) in contrast with carvedilol coarse suspensions. Moreover, carvedilol nanosuspensions showed good biocompatibility with the rat gastric mucosa in in vivo gastrointestinal irritation test. The entire results implicated that the dissolution rate and the oral absorption of carvedilol were significantly affected by the particle size. Particle size reduction to form nanosized particles was found to be an efficient method for improving the oral bioavailability of carvedilol. PMID:26508852

Outdoor surface temperature measurement: ground truth or lie?

NASA Astrophysics Data System (ADS)

Skauli, Torbjorn

2004-08-01

Contact surface temperature measurement in the field is essential in trials of thermal imaging systems and camouflage, as well as for scene modeling studies. The accuracy of such measurements is challenged by environmental factors such as sun and wind, which induce temperature gradients around a surface sensor and lead to incorrect temperature readings. In this work, a simple method is used to test temperature sensors under conditions representative of a surface whose temperature is determined by heat exchange with the environment. The tested sensors are different types of thermocouples and platinum thermistors typically used in field trials, as well as digital temperature sensors. The results illustrate that the actual measurement errors can be much larger than the specified accuracy of the sensors. The measurement error typically scales with the difference between surface temperature and ambient air temperature. Unless proper care is taken, systematic errors can easily reach 10% of this temperature difference, which is often unacceptable. Reasonably accurate readings are obtained using a miniature platinum thermistor. Thermocouples can perform well on bare metal surfaces if the connection to the surface is highly conductive. It is pointed out that digital temperature sensors have many advantages for field trials use.

Variability of AVHRR-Derived Clear-Sky Surface Temperature over the Greenland Ice Sheet.

NASA Astrophysics Data System (ADS)

Stroeve, Julienne; Steffen, Konrad

1998-01-01

The Advanced Very High Resolution Radiometer is used to derive surface temperatures for one satellite pass under clear skies over the Greenland ice sheet from 1989 through 1993. The results of these temperatures are presented as monthly means, and their spatial and temporal variability are discussed. Accuracy of the dry snow surface temperatures is estimated to be better than 1 K during summer. This error is expected to increase during polar night due to problems in cloud identification. Results indicate the surface temperature of the Greenland ice sheet is strongly dominated by topography, with minimum surface temperatures associated with the high elevation regions. In the summer, maximum surface temperatures occur during July along the western coast and southern tip of the ice sheet. Minimum temperatures are found at the summit during summer and move farther north during polar night. Large interannual variability in surface temperatures occurs during winter associated with katabatic storm events. Summer temperatures show little variation, although 1992 stands out as being colder than the other years. The reason for the lower temperatures during 1992 is believed to be a result of the 1991 eruption of Mount Pinatubo.

Areas of Weakly Anomalous to Anomalous Surface Temperature in Alamosa and Saguache Counties, Colorado, as Identified from ASTER Thermal Data

DOE Data Explorer

Khalid Hussein

2012-02-01

This "Weakly Anomalous to Anomalous Surface Temperature" dataset differs from the "Anomalous Surface Temperature" dataset for this county (another remotely sensed CIRES product) by showing areas of modeled temperatures between 1o and 2o above the mean, as opposed to the greater than 2o temperatures contained in the "Anomalous Surface Temperature" dataset. Note: 'o' is used in this description to represent lowercase sigma

A study on the magnetic susceptibilities and optical absorption spectra on single crystals of Gd(III) pyrogermanate

NASA Astrophysics Data System (ADS)

Kundu, T.; Ghosh, D.; Wanklyn, B. M.

1990-04-01

The paper reports for the first time the experimental results of the measurements of magnetic susceptibilities ( K⊥ and K|) and their anisotropy (Δ K) between 300 and 21.8 K and the optical absorption spectra (UV region) at 12.5 K on single crystals of gadolinium pyrogermanate (GdPG). The anisotropy, which is only 211×10 -6 emu/mol at room temperature and increases by two orders of magnitude at 21 K, is predominantly a crystal field (CF) effect on the 8S {7}/{2} ground term, through higher order perturbations. Interpretation of the observed magnetic data was carried out by considering a conventional spin Hamiltonian ( Hs) to derive expressions for K⊥ and K| in terms of four effective crystal field parameters (ECFP). The value s of ECFP were varied to obtain a very close fitting between the theoretical and experimental values of K⊥, K|, δ K and K¯ The splitting of the 8S {7}/{2} term corresponding to these values of ECFP was found to be large, which suggests a strong CF effect in GdPG, as also observed in other RPG crystal studied earlier. The thermal characteristics of the magnetic anisotropy below 30 K deviate by about 5% which could not be explained by CF effects alone. A series expansion method was adopted to analyse the results of K⊥ and K| below 30 K, however the corresponding coefficient B2α and B3α were observed t o be unusually high indicating the presence of CF effect even in this temperature region. The Schottky specific heat, Csch, between 300 and 21 K for GdPG has been calculated and this shows a maximum at Tmax=17 K.

Conformal Microwave Array (CMA) Applicators for Hyperthermia of Diffuse Chestwall Recurrence

PubMed Central

Stauffer, Paul R.; Maccarini, Paolo; Arunachalam, Kavitha; Craciunescu, Oana; Diederich, Chris; Juang, Titania; Rossetto, Francesca; Schlorff, Jaime; Milligan, Andrew; Hsu, Joe; Sneed, Penny; Vujaskovic, Zeljko

2010-01-01

Purpose This article summarizes the evolution of microwave array applicators for heating large area chestwall disease as an adjuvant to external beam radiation, systemic chemotherapy, and potentially simultaneous brachytherapy. Methods Current devices used for thermotherapy of chestwall recurrence are reviewed. The largest conformal array applicator to date is evaluated in four studies: i) ability to conform to the torso is demonstrated with a CT scan of a torso phantom and MR scan of the conformal waterbolus component on a mastectomy patient; ii) Specific Absorption Rate (SAR) and temperature distributions are calculated with electromagnetic and thermal simulation software for a mastectomy patient; iii). SAR patterns are measured with a scanning SAR probe in liquid muscle phantom for a buried coplanar waveguide CMA; and iv) heating patterns and patient tolerance of CMA applicators are characterized in a clinical pilot study with 13 patients. Results CT and MR scans demonstrate excellent conformity of CMA applicators to contoured anatomy. Simulations demonstrate effective control of heating over contoured anatomy. Measurements confirm effective coverage of large treatment areas with no gaps. In 42 hyperthermia treatments, CMA applicators provided well-tolerated effective heating of up to 500cm2 regions, achieving target temperatures of Tmin=41.4±0.7°C, T90=42.1±0.6°C, Tave=42.8±0.6°C, and Tmax=44.3±0.8°C as measured in an average of 90 points per treatment. Summary The CMA applicator is an effective thermal therapy device for heating large-area superficial disease such as diffuse chestwall recurrence. It is able to cover over three times the treatment area of conventional hyperthermia devices while conforming to typical body contours. PMID:20849262

The effects of orbital and climatic variations on Martian surface heat flow

NASA Technical Reports Server (NTRS)

Mellon, Michael T.; Jakosky, Bruce M.

1993-01-01

Large changes in the orbital elements of Mars on timescales of 10(exp 4) to 10(exp 6) years will cause widely varying climate, specifically surface temperatures, as a result of varying insolation. These surface temperature oscillations will produce subsurface thermal gradients which contribute to the total surface heat flux. We investigate the thermal behavior of the Martian regolith on orbital timescales and show that this climatological surface heat flux is spatially variable and contributes significantly to the total surface heat flux at many locations. We model the thermal behavior of the Martian regolith by calculating the mean annual surface temperatures for each epoch (spaced 1000 years apart to resolve orbital variations) for the past 200,000 years at a chosen location on the surface. These temperatures are used as a boundary condition for the deeper regolith and subsurface temperature oscillation are then computed. The surface climatological heat flux due to past climate changes can then be found from the temperature gradient between the surface and about 150 m depth (a fraction of the thermal skin depth on these timescales). This method provides a fairly accurate determination of the climatological heat flow component at a point; however, this method is computationally time consuming and cannot be applied to all points on the globe. To map the spatial variations in the surface heat flow we recognize that the subsurface temperature structure will be largely dominated by the most recent surface temperature oscillations. In fact, the climate component of the surface heat flow will be approximately proportional to the magnitude of the most recent surface temperature change. By calculating surface temperatures at all points globally for the present epoch and an appropriate past epoch, and combining these results with a series of more precise calculations described above, we estimate the global distribution of climatological surface heat flow.

Soil moisture sensing with aircraft observations of the diurnal range of surface temperature

NASA Technical Reports Server (NTRS)

Schmugge, T. J.; Blanchard, B.; Anderson, A.; Wang, V.

1977-01-01

Aircraft observations of the surface temperature were made by measurements of the thermal emission in the 8-14 micrometers band over agricultural fields around Phoenix, Arizona. The diurnal range of these surface temperature measurements were well correlated with the ground measurement of soil moisture in the 0-2 cm layer. The surface temperature observations for vegetated fields were found to be within 1 or 2 C of the ambient air temperature indicating no moisture stress. These results indicate that for clear atmospheric conditions remotely sensed surface temperatures are a reliable indicator of soil moisture conditions and crop status.

Core body temperature, skin temperature, and interface pressure. Relationship to skin integrity in nursing home residents.

PubMed

Knox, D M

1999-06-01

To ascertain the effects of 1-, 1 1/2-, and 2-hour turning intervals on nursing home residents' skin over the sacrum and trochanters. (1) the higher the core body temperature, the higher the skin surface temperature; (2) the 2-hour turning interval would have significantly higher skin surface temperature; (3) there would be no relationship between skin surface temperature and interface pressure; and (4) the sacrum would have the lowest skin surface temperature. Modified Latin-square. For-profit nursing home. Convenience sample of 26 residents who scored < 3 on the Short Portable Mini-Mental Status Questionnaire and did not have (1) open wounds; (2) albumin levels < 3.3 mg/dL; (3) severe arthritis; (4) cortisone, anticoagulation, insulin therapy or 3 medications for hypertension; and/or (5) were totally bedridden. First Temp measured core temperature; a disposable thermistor temperature probe, skin temperature; and a digital interface pressure evaluator, the interface pressure. Negative correlation (r = -.33, P = .003) occurred between core body temperature and skin surface temperature. Skin surface temperature rose at the end of the 2-hour turning interval but was not significant (F = (2.68) = .73, P = .49). Weak negative relationship (r = -12, P = .29) occurred between skin surface temperature and interface pressure, and sacral skin surface temperature was significantly lower for the left trochanter only (F = (8.68) = 7.05, P = .002). Although hypotheses were not supported, more research is needed to understand how time in position and multiple chronic illnesses interact to affect skin pressure tolerance.

Quantifying the impact of human activity on temperatures in Germany

NASA Astrophysics Data System (ADS)

Benz, Susanne A.; Bayer, Peter; Blum, Philipp

2017-04-01

Human activity directly influences ambient air, surface and groundwater temperatures. Alterations of surface cover and land use influence the ambient thermal regime causing spatial temperature anomalies, most commonly heat islands. These local temperature anomalies are primarily described within the bounds of large and densely populated urban settlements, where they form so-called urban heat islands (UHI). This study explores the anthropogenic impact not only for selected cities, but for the thermal regime on a countrywide scale, by analyzing mean annual temperature datasets in Germany in three different compartments: measured surface air temperature (SAT), measured groundwater temperature (GWT), and satellite-derived land surface temperature (LST). As a universal parameter to quantify anthropogenic heat anomalies, the anthropogenic heat intensity (AHI) is introduced. It is closely related to the urban heat island intensity, but determined for each pixel (for satellite-derived LST) or measurement point (for SAT and GWT) of a large, even global, dataset individually, regardless of land use and location. Hence, it provides the unique opportunity to a) compare the anthropogenic impact on temperatures in air, surface and subsurface, b) to find main instances of anthropogenic temperature anomalies within the study area, in this case Germany, and c) to study the impact of smaller settlements or industrial sites on temperatures. For all three analyzed temperature datasets, anthropogenic heat intensity grows with increasing nighttime lights and declines with increasing vegetation, whereas population density has only minor effects. While surface anthropogenic heat intensity cannot be linked to specific land cover types in the studied resolution (1 km × 1 km) and classification system, both air and groundwater show increased heat intensities for artificial surfaces. Overall, groundwater temperature appears most vulnerable to human activity; unlike land surface temperature and surface air temperature, groundwater temperatures are elevated in cultivated areas as well. At the surface of Germany, the highest anthropogenic heat intensity with 4.5 K is found at an open-pit lignite mine near Jülich, followed by three large cities (Munich, Düsseldorf and Nuremberg) with annual mean anthropogenic heat intensities > 4 K. Overall, surface anthropogenic heat intensities > 0 K and therefore urban heat islands are observed in communities down to a population of 5,000.

Correlation of Water Frost Porosity in Laminar Flow over Flat Surfaces

NASA Technical Reports Server (NTRS)

Kandula, Max

2011-01-01

A dimensionless correlation has been proposed for water frost porosity expressing its dependence on frost surface temperature and Reynolds number for laminar forced flow over a flat surface. The correlation is presented in terms of a dimensionless frost surface temperature scaled with the cold plate temperature, and the freezing temperature. The flow Reynolds number is scaled with reference to the critical Reynolds number for laminar-turbulent transition. The proposed correlation agrees satisfactorily with the simultaneous measurements of frost density and frost surface temperature covering a range of plate temperature, ambient air velocity, humidity, and temperature. It is revealed that the frost porosity depends primarily on the frost surface and the plate temperatures and the flow Reynolds number, and is only weakly dependent on the relative humidity. The results also point out the general character of frost porosity displaying a decrease with an increase in flow Reynolds number.

Detection of surface temperature from LANDSAT-7/ETM+

NASA Astrophysics Data System (ADS)

Suga, Y.; Ogawa, H.; Ohno, K.; Yamada, K.

2003-12-01

Hiroshima Institute of Technology (HIT) in Japan has established a LANDSAT-7 Ground Station in cooperation with NASDA for receiving and processing the ETM+ data on March 15 th, 2000 in Japan. The authors performed a verification study on the surface temperature derived from thermal infrared band image data of LANDSAT 7/Enhanced Thematic Mapper Plus (ETM+) for the estimation of temperatures around Hiroshima city and bay area in the western part of Japan as a test site. As to the thermal infrared band, the approximate functions for converting the spectral radiance into the surface temperature are estimated by considering both typical surface temperatures measured by the simultaneous field survey with the satellite observation and the spectral radiance observed by ETM+ band 6 (10.40-12.50μm), and then the estimation of the surface temperature distribution around the test site was examined.In this study, the authors estimated the surface temperature distribution equivalent to the land cover categories around the test site for establishing a guideline of surface temperature detection by LANDSAT7/ETM+ data. As the result of comparison of the truth data and the estimated surface temperature, the correlation coefficients of the approximate function referred to the truth data are from 0.9821 to 0.9994, and the differences are observed from +0.7 to -1.5°C in summer, from +0.4 to -0.9 *C in autumn, from -1.6 to -3.4°C in winter and from +0.5 to -0.5C in spring season respectively. It is clearly found that the estimation of surface temperature based on the approximate functions for converting the spectral radiance into the surface temperature referred to the truth data is improved over the directly estimated surface temperature obtained from satellite data. Finally, the successive seasonal change of surface temperature distribution pattern of the test site is precisely detected with the temperature legend of 0 to 80'C derived from LANDSAT-7/ETM+ band 6 image data for the thermal environment monitoring. 2003 COSPAR. Published by Elsevier Ltd.

Exposure assessment of aluminum arc welding radiation.

PubMed

Peng, Chiung-yu; Lan, Cheng-hang; Juang, Yow-jer; Tsao, Ta-ho; Dai, Yu-tung; Liu, Hung-hsin; Chen, Chiou-jong

2007-10-01

The purpose of this study is to evaluate the non-ionizing radiation (NIR) exposure, especially optical radiation levels, and potential health hazard from aluminum arc welding processes based on the American Conference of Governmental Industrial Hygienists (ACGIH) method. The irradiance from the optical radiation emissions can be calculated with various biological effective parameters [i.e., S(lambda), B(lambda), R(lambda)] for NIR hazard assessments. The aluminum arc welding processing scatters bright light with NIR emission including ultraviolet radiation (UVR), visible, and infrared spectra. The UVR effective irradiance (Eeff) has a mean value of 1,100 microW cm at 100 cm distance from the arc spot. The maximum allowance time (tmax) is 2.79 s according to the ACGIH guideline. Blue-light hazard effective irradiance (EBlue) has a mean value of 1840 microW cm (300-700 nm) at 100 cm with a tmax of 5.45 s exposure allowance. Retinal thermal hazard effective calculation shows mean values of 320 mW cm(-2) sr(-1) and 25.4 mW (cm-2) (380-875 nm) for LRetina (spectral radiance) and ERetina (spectral irradiance), respectively. From this study, the NIR measurement from welding optical radiation emissions has been established to evaluate separate types of hazards to the eye and skin simultaneously. The NIR exposure assessment can be applied to other optical emissions from industrial sources. The data from welding assessment strongly suggest employees involved in aluminum welding processing must be fitted with appropriate personal protection devices such as masks and gloves to prevent serious injuries of the skin and eyes upon intense optical exposure.

In-vitro and In-vivo Pharmacokinetic Evaluation of Guar Gum-Eudragit® S100 Based Colon-targeted Spheroids of Sulfasalazine Co-administered with Probiotics.

PubMed

Sharma, Abhinav; Kumar, Bimlesh; Singh, Sachin Kumar; Gulati, Monica; Vaidya, Yogyata; Rathee, Harish; Ghai, Deepak; Malik, Adil Hussain; Yadav, Ankit Kumar; Maharshi, Peddi; Bawa, Palak; Rajesh, Sarvi Yadav; Sharma, Parth; Pandey, Narendra Kumar; Mohanta, Souvik

2018-01-01

Polysaccharide based delivery systems have been successfully used to target drugs to colon. In some recent reports, the superiority of concomitant administration of probiotics with such systems has been established. However, the pharmacokinetics of such symbiotic therapy remain unexplored hitherto. This study deciphers the pharmacokinetic parameters of guar gum based colon targeted spheroids of sulfasalazine with co-administration of probiotics in experimental rats. Thirty rats were divided into five groups using Latin square design. These were subjected to treatment with delayed release formulation, uncoated spheroids, coated spheroid and coated spheroids along with probiotics. In case of delayed release formulation, negligible presence of sulfasalazine in plasma was observed in first 2h, followed by significant increase in sulfasalazine concentration after 3h. Higher plasma concentrations of sulfasalazine were detected for uncoated spheroids with and without probiotics. Negligible release of drug upto 5h and delayed Tmax in case of guar-gum coated sulfasalazine spheroids with or without probiotics clearly indicated successful formulation of colon targeted spheroids. Further, for coated spheroids (both with and without probiotics), the value of Tmax is found to be significantly higher than those with the other treatments. Colon targeted spheroids were therefore, found to reduce absorption of drug which, in turn, is expected to reduce the side effects as only local action in colon is required for treatment of colitis. This is the first report on pharmacokinetic study of a colon targeted delivery system co-administered with probiotics. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Rectal administration of propylthiouracil in hyperthyroid patients: comparison of suspension enema and suppository form.

PubMed

Jongjaroenprasert, W; Akarawut, W; Chantasart, D; Chailurkit, L; Rajatanavin, R

2002-07-01

Previous studies have described the therapeutic effects of propylthiouracil (PTU) and methimazole in normal subjects after rectal suppositories. The goal of our study was to compare the pharmacokinetic and pharmacologic effects of a suppository and suspension form of PTU given per rectum. Fifteen newly diagnosed hyperthyroid patients of both genders (ages 21 to 55 years) were randomly given the drug as follows: group 1 (n = 7), a single enema (400 mg of PTU in 90 mL of sterile water) and group 2 (n = 8), two suppositories of polyethylene glycol base (200 mg of PTU in each). The pharmacokinetic study revealed earlier time to peak levels (T(max)) and significantly greater maximal peak levels (C(max)) in group 1 than in group 2, (85.71 +/- 12.12 minutes vs. 172.5 +/- 26.24 minutes for T(max) and 3.89 +/- 0.34 vs. 2.01 +/- 0.38 microg/mL, p < 0.05 for C(max), respectively). However, the area under the curve (635.16 +/- 105.71 vs. 377.87 +/- 68.09 microg x min/mL) was not statistically different between both groups. Both forms induced a significant decrease in serum free triiodothyronine (FT(3)) levels and an increase in serum rT(3) levels shortly after administration. Four subjects reported a bitter taste 5-10 minutes after receiving the drug. PTU can be effectively absorbed via the rectal route. The enema form appeared to provide better bioavailability than the suppository form. However, both preparations exhibited comparable therapeutic effect.

Pharmacokinetics and bioavailability of denaverine hydrochloride in healthy subjects following intravenous, oral and rectal single doses.

PubMed

Staab, Alexander; Schug, Barbara S; Larsimont, Véronique; Elze, Martina; Thümmler, Daniela; Mutschler, Ernst; Blume, Henning

2003-02-01

The neurotropic-musculotropic spasmolytic agent denaverine hydrochloride is used mainly in the treatment of smooth muscle spasms of the gastrointestinal and urogenital tract. Despite its commercial availability as a solution for intravenous or intramuscular administration (ampoule) and as a suppository formulation, no pharmacokinetic data in man was available to date. Therefore, the objectives of this clinical trial were to determine the basic pharmacokinetic parameters of denaverine after intravenous administration, to assess the feasibility of using the oral route of administration and to characterise the bioavailability of the suppository formulation. To achieve this, healthy subjects received 50 mg denaverine hydrochloride intravenously, orally and rectally in aqueous solutions and rectally as suppository in an open, randomised crossover design. Total body clearance, volume of distribution at steady-state and half-life of denaverine are 5.7 ml/min per kg, 7.1 l/kg and 33.8 h, respectively. The absolute bioavailability after oral administration of an aqueous solution is 37%. First-pass metabolism leading to the formation of N-monodemethyl denaverine was found to be one reason for the incomplete bioavailability after oral administration. Rectal administration of an aqueous solution of denaverine hydrochloride resulted in a decreased rate (median of C(max) ratios: 26%, difference in median t(max) values: 1.9 h) and extent (31%) of bioavailability compared to oral administration. Using the suppository formulation led to a further reduction in rate (median of C(max) ratios: 30%, difference in median t(max) values: 3 h) and extent (42%) of bioavailability compared to the rectal solution.

Pharmacokinetic characterization of three novel 4-mg nicotine lozenges
.

PubMed

Sukhija, Manpreet; Srivastava, Reena; Kaushik, Aditya

2018-03-01

Nicotine replacement therapy (NRT) increases the probability of smoking cessation. This study was conducted to determine if three prototype 4-mg nicotine lozenges produced locally in India were bioequivalent to a globally marketed reference product, Nicorette® 4-mg nicotine lozenge. Healthy adult smokers (N = 39) were treated with three prototype 4-mg nicotine lozenges in comparison with a reference 4-mg lozenge in this single-center, randomized, open-label, single-dose, 4-way crossover study. Pharmacokinetic sampling was obtained to test for bioequivalence using maximal plasma concentration (Cmax) and extent of absorption (AUC0-t). Secondarily, AUC;0-∞, time to maximal plasma concentration (tmax), half-life (T1/2), elimination rate constant (Kel), and safety of the prototype lozenges versus the reference lozenge were compared. Each prototype 4-mg nicotine lozenge was found to be bioequivalent to the reference 4-mg nicotine lozenge based on the ratio of geometric means and 90% confidence intervals for Cmax, AUC0-t, and AUC;0-∞. Although tmax; was significantly longer for prototype III, all four lozenges achieved maximum plasma nicotine concentrations at a median of 1.5 hours. The safety profiles of the three prototype 4-mg lozenges did not differ from that of the 4-mg reference product. Each prototype 4-mg nicotine lozenge was bioequivalent to the reference 4-mg nicotine lozenge and was well tolerated. Furthermore, as these bioequivalent prototypes differed in in-vitro dissolution profiles, these data suggest that performance from the in -vitro method deployed is not a firm predictor of pharmacokinetic behavior.
.

Development, evaluation and pharmacokinetics of time-dependent ketorolac tromethamine tablets.

PubMed

Vemula, Sateesh Kumar; Veerareddy, Prabhakar Reddy

2013-01-01

The present study was intended to develop a time-dependent colon-targeted compression-coated tablets of ketorolac tromethamine (KTM) using hydroxypropyl methylcellulose (HPMC) that release the drug slowly but completely in the colonic region by retarding the drug releases in stomach and small intestine. KTM core tablets were prepared by direct compression method and were compression coated with HPMC. The formulation is optimized based on the in vitro drug release studies and further evaluated by X-ray imaging technique in healthy humans to ensure the colonic delivery. To prove these results, in vivo pharmacokinetic studies in human volunteers were designed to study the in vitro-in vivo correlation. From the in vitro dissolution study, optimized formulation F3 showed negligible drug release (6.75 ± 0.49%) in the initial lag period followed by slow release (97.47 ± 0.93%) for 24 h which clearly indicates that the drug is delivered to the colon. The X-ray imaging studies showed that the tablets reached the colon without disintegrating in upper gastrointestinal system. From the pharmacokinetic evaluation, the immediate-release tablets producing peak plasma concentration (C(max)) was 4482.74 ng/ml at 2 h T(max) and colon-targeted tablets showed C(max) = 3562.67 ng/ml at 10 h T(max). The area under the curve for the immediate-release and compression-coated tablets was 10595.14 and 18796.70 ng h/ml and the mean resident time was 3.82 and 10.75 h, respectively. Thus, the compression-coated tablets based on time-dependent approach were preferred for colon-targeted delivery of ketorolac.

Correlation Between Gastric Emptying and Gastric Adaptive Relaxation Influenced by Amino Acids

PubMed Central

Uchida, Masayuki; Kobayashi, Orie; Saito, Chizuru

2017-01-01

Background/Aims Amino acids have many physiological activities. We report the correlation between gastric emptying and gastric adaptive relaxation using tryptophan and amino acids with a straight alkyl chain, hydroxylated chain, and branched chain. Here we sought to further clarify the correlation between gastric emptying and gastric adaptive relaxation by using other amino acids. Methods In Sprague-Dawley rats, gastric emptying was evaluated by a breath test using [1-13C] acetic acid. The expired 13CO2 pattern, Tmax, Cmax, and AUC120min values were used as evaluation items. Gastric adaptive relaxation was evaluated in a barostat experiment. Individual amino acids (1 g/kg) were administered orally 30 minutes before each breath test or barostat test. Results L-phenylalanine and L-tyrosine did not influence gastric emptying. All other amino acids, ie, L-proline, L-histidine, L-cysteine, L-methionine, L-aspartic acid, L-glutamic acid, L-asparagine, L-arginine, L-glutamine, and L-lysine significantly delayed and inhibited gastric emptying. L-Cysteine and L-aspartic acid significantly enhanced and L-methionine and L-glutamine significantly inhibited gastric adaptive relaxation. L-Phenylalanine moved the balloon toward the antrum, suggesting strong contraction of the fundus. Tmax showed a significant positive correlation (r = 0.709), and Cmax and AUC120min each showed negative correlations (r = 0.613 and 0.667, respectively) with gastric adaptive relaxation. Conclusion From the above findings, it was found that a close correlation exists between gastric emptying and adaptive relaxation, suggesting that enhanced gastric adaptive relaxation inhibits gastric emptying. PMID:28335103

Development of an in vitro cell culture model to study milk to plasma ratios of therapeutic drugs.

PubMed

Athavale, Maithili A; Maitra, Anurupa; Patel, Shahnaz; Bhate, Vijay R; Toddywalla, Villi S

2013-01-01

To create an in vitro cell culture model to predict the M/P (concentration of drug in milk/concentration in maternal plasma) ratios of therapeutic drugs viz. rifampicin, theophylline, paracetamol, and aspirin. An in vitro cell culture model using CIT3 cells (mouse mammary epithelial cells) was created by culturing the cells on transwells. The cells formed an integral monolayer, allowing only transcellular transport as it happens in vivo. Functionality of the cells was confirmed through scanning electron microscopy. Time wise transfer of the study drugs from plasma to milk was studied and compared with actual (in vivo) M/P ratios obtained at reported tmax for the respective drugs. The developed model mimicked two important intrinsic factors of mammary epithelial cells viz. secretory and tight-junction properties and also the passive route of drug transport. The in vitro M/P ratios at reported tmax were 0.23, 0.61, 0.87, and 0.03 respectively, for rifampicin, theophylline, paracetamol, and salicylic acid as compared to 0.29, 0.65, 0.65, and 0.22, respectively, in vitro. Our preliminary effort to develop an in vitro physiological model showed promising results. Transfer rate of the drugs using the developed model compared well with the transfer potential seen in vivo except for salicylic acid, which was transferred in far lower concentration in vitro. The model has a potential to be developed as a non-invasive alternative to the in vitro technique for determining the transfer of therapeutic drugs into breast milk.

Bioequivalence of generic and branded amoxicillin capsules in healthy human volunteers

PubMed Central

Pathak, Priyanka; Pandit, Vijaya A.; Dhande, Priti P.

2017-01-01

CONTEXT: The Medical Council of India urges doctors to prescribe generic drugs as far as possible. The Indian Medical Association had responded earlier saying that it requires guarantees on the quality of generic forms of drugs. Although no published scientific reports are available on the issue of therapeutic inequivalence, unconfirmed clinician accounts and newspaper reports of therapeutic inequivalence exist. AIM: This study was planned to ascertain whether bioequivalence of branded and generic amoxicillin capsule is comparable. SETTINGS AND DESIGN: An open-label, randomized, single-dose, two-treatment, two-sequence, two-period crossover oral bioequivalence study was conducted in 12 healthy, adult human subjects under fasting condition. MATERIALS AND METHODS: Serum samples, collected at 8 time points, were analyzed by a validated ultraviolet spectrophotometer method. Pharmacokinetic (PK) parameters such as area under the curve (AUC)0–t, AUC0–∞, Cmax, and Tmax were determined along with time above minimum inhibitory concentration (MIC). STATISTICAL ANALYSIS USED: The log-transformed PK parameters (Cmax, AUC0–t, AUC0–∞) were analyzed using a Two One-Sided Test ANOVA in SAS for each parameter. Tmax and MIC were analyzed by Wilcoxon rank-sum test in GraphPad Prism. RESULTS: Geometric mean ratio of Cmax fell within bioequivalence criteria. The upper and lower confidence limits of both AUC0–t and AUC0–∞ geometric mean ratio fell below bioequivalence criteria. Time above MIC of generic preparation was significantly lower than that of branded version. CONCLUSIONS: The generic capsule was not bioequivalent to the branded amoxicillin capsule. PMID:28706331

Development of coated nifedipine dry elixir as a long acting oral delivery with bioavailability enhancement.

PubMed

Choi, Jae-Yoon; Jin, Su-Eon; Park, Youmie; Lee, Hyo-Jong; Park, Yohan; Maeng, Han-Joo; Kim, Chong-Kook

2011-10-01

To develop the long acting nifedipine oral delivery with bioavailability enhancement, a nifedipine dry elixir (NDE) containing nifedipine ethanol solution in dextrin shell was prepared using a spray-dryer, and then coated nifedipine dry elixir (CNDE) was prepared by coating NDE with Eudragit acrylic resin. The physical characteristics and bioavailability of NDE and CNDE were evaluated, and then compared to those of nifedipine powder. NDE and CNDE, which were spherical in shape, had about 6.64 and 8.68-8.75 μm of geometric mean diameters, respectively. The amount of nifedipine dissolved from NDE for 60 min increased about 7- and 40-fold compared to nifedipine powder in pH 1.2 simulated gastric fluid and pH 6.8 simulated intestinal fluid, respectively. Nifedipine released from CNDE was retarded in both dissolution media compared with that from NDE. After oral administration of NDE, the C(max) and AUC(0→8h) of nifedipine in rat increased about 13- and 7-fold, respectively, and the Tmax of nifedipine was reduced significantly compared with those after oral administration of nifedipine powder alone. The AUC(0→8h) and T(max) of nifedipine in CNDE increased markedly and the C(max) of nifedipine in CNDE was significantly reduced compared to those in NDE. It is concluded that CNDE, which could lower the initial burst-out plasma concentration and maintain the plasma level of nifedipine over a longer period with bioavailability enhancement, might be one of potential alternatives to the marketed long acting oral delivery system for nifedipine.

Evaluation of brain targeting and mucosal integrity of nasally administrated nanostructured carriers of a CNS active drug, clonazepam.

PubMed

Abdel-Bar, Hend Mohamed; Abdel-Reheem, Amal Youssef; Awad, Gehanne Abdel Samie; Mortada, Nahed Daoud

2013-01-01

The aim of the study was to target clonazepam, a CNS active drug, to the brain through the non-invasive intranasal (in) route using of nanocarriers with proven safety in clonazepam nanocarriers were prepared by mixing isopropyl myristate, Tween 80, Cremophor EL or lecithin, polyethylene glycol 200, propylene glycol or ethanol in different ratios with water. in-vitro characterization of the nanocarriers was done by various methods including: polarized light microscopy, particle size determination, viscosity measurements and drug release studies. in-vivo study comparing intranasal and intravenous administration was performed. The drug targeting efficiency (DTE %) and direct nose to brain transport percentage (DTP %) were calculated and nasal integrity assessment was carried out. The obtained formulae had particle size below 100 nm favoring rapid direct nose to brain transport and the time for 100% drug release (T100%) depended on systems composition. Plasma Tmax of clonazepam nanostructured carriers varied from 10-30 min., while their brain Tmax did not exceed 10 min, in comparison with 30 min for iv solution. Although there was no significant difference (p>0.05) between the plasma AUC0-∞ of the different tested nanocarriers and intravenous one, the increase in brain AUC 0 -∞ of different nasal formulations in comparison to that of iv administration (3.6 -7.2 fold) confirms direct nose to brain transport via olfactory region. Furthermore, DTE and DTP% confirmed brain targeting of clonazepam following intranasal administration. The results confirmed that intranasal nanocarriers were proved to be safe alternative for iv clonazepam delivery with rapid nose to brain transport.

Reproductive characteristics and population decline of four species of skate (Rajidae) off the eastern coast of Canada.

PubMed

Mcphie, R P; Campana, S E

2009-07-01

Four of the most common species of skate (Rajidae) were studied off eastern Canada to determine if their reproductive characteristics were linked to their population trajectories. The fecundity of the winter skate Leucoraja ocellata, the little skate Leucoraja erinacea, the thorny skate Amblyraja radiata and the smooth skate Malacoraja senta averaged between 41 and 56 egg cases per year for each species. For all species but L. ocellata, males matured at larger sizes and at later ages than females. Theoretical rates of population increase for non-equilibrium populations of L. ocellata (c. 0.07), M. senta (c. 0.14) and L. erinacea and A. radiata (c. 0.20) were low compared to most fishes, indicating that north-west Atlantic skates are intrinsically unproductive, yet are theoretically capable of supporting low-level fisheries. Nevertheless, the results of 36 years of research surveys indicate that the abundance of mature L. ocellata, A. radiata and M. senta all decreased by >90% since 1970, indicating that past fishing mortality (both directed and undirected) has outstripped the net productivity of the skate populations on the eastern Scotian Shelf. The relationship between maximum age (t(max)) and age of maturity (t(mat)) was a better predictor of population growth rate than was body size, with the species exhibiting the highest ratios of t(mat) :t(max) (L. ocellata = 0.68, M. senta = 0.66) having the lowest predicted population growth rates. L. ocellata appears to have the lowest productivity and has experienced the greatest population decline, thus raising concerns over its future status.

Influence of CYP2D6 activity on the pharmacokinetics and pharmacodynamics of a single 20 mg dose of ibogaine in healthy volunteers.

PubMed

Glue, Paul; Winter, Helen; Garbe, Kira; Jakobi, Hannah; Lyudin, Alexander; Lenagh-Glue, Zoe; Hung, C Tak

2015-06-01

Conversion of ibogaine to its active metabolite noribogaine appears to be mediated primarily by CYP2D6. We compared 168 hours pharmacokinetic profiles of both analytes after a single oral 20 mg dose of ibogaine in 21 healthy subjects who had been pretreated for 6 days with placebo or the CYP2D6 inhibitor paroxetine. In placebo-pretreated subjects, ibogaine was rapidly converted to noribogaine. Median peak noribogaine concentrations occurred at 4 hours. Compared with placebo-pretreated subjects, paroxetine-pretreated subjects had rapid (Tmax  = 1.5 hours) and substantial absorption of ibogaine, with detectable levels out to 72 hours, and an elimination half-life of 10.2 hours. In this group, ibogaine was also rapidly converted to noribogaine with a median Tmax of 3 hours. Extent of noribogaine exposure was similar in both groups. CYP2D6 phenotype was robustly correlated with ibogaine AUC0-t (r = 0.82) and Cmax (r = 0.77). Active moiety (ibogaine plus noribogaine) exposure was ∼2-fold higher in paroxetine-pretreated subjects. Single 20 mg ibogaine doses were safe and well tolerated in all subjects. The doubling of exposure to active moiety in subjects with reduced CYP2D6 activity suggests it may be prudent to genotype patients awaiting ibogaine treatment, and to at least halve the intended dose of ibogaine in CYP2D6 poor metabolizers. © 2015, The American College of Clinical Pharmacology.

Application of radiometric surface temperature for surface energy balance estimation: John Monteith's contributions

USDA-ARS?s Scientific Manuscript database

Over 25 years ago, Huband and Monteith paper’s investigating the radiative surface temperature and the surface energy balance of a wheat canopy, highlighted the key issues in computing fluxes with radiometric surface temperature. These included the relationship between radiometric and aerodynamic s...

Molecular dynamics simulation of temperature effects on low energy near-surface cascades and surface damage in Cu

NASA Astrophysics Data System (ADS)

Zhu, Guo; Sun, Jiangping; Guo, Xiongxiong; Zou, Xixi; Zhang, Libin; Gan, Zhiyin

2017-06-01

The temperature effects on near-surface cascades and surface damage in Cu(0 0 1) surface under 500 eV argon ion bombardment were studied using molecular dynamics (MD) method. In present MD model, substrate system was fully relaxed for 1 ns and a read-restart scheme was introduced to save total computation time. The temperature dependence of damage production was calculated. The evolution of near-surface cascades and spatial distribution of adatoms at varying temperature were analyzed and compared. It was found that near-surface vacancies increased with temperature, which was mainly due to the fact that more atoms initially located in top two layers became adatoms with the decrease of surface binding energy. Moreover, with the increase of temperature, displacement cascades altered from channeling-like structure to branching structure, and the length of collision sequence decreased gradually, because a larger portion of energy of primary knock-on atom (PKA) was scattered out of focused chain. Furthermore, increasing temperature reduced the anisotropy of distribution of adatoms, which can be ascribed to that regular registry of surface lattice atoms was changed with the increase of thermal vibration amplitude of surface atoms.

Corresponding states correlation for temperature dependent surface tension of normal saturated liquids

NASA Astrophysics Data System (ADS)

Yi, Huili; Tian, Jianxiang

2014-07-01

A new simple correlation based on the principle of corresponding state is proposed to estimate the temperature-dependent surface tension of normal saturated liquids. The correlation is a linear one and strongly stands for 41 saturated normal liquids. The new correlation requires only the triple point temperature, triple point surface tension and critical point temperature as input and is able to represent the experimental surface tension data for these 41 saturated normal liquids with a mean absolute average percent deviation of 1.26% in the temperature regions considered. For most substances, the temperature covers the range from the triple temperature to the one beyond the boiling temperature.

Thermo-analytical and physico-chemical characterisation of organoclays and polymer-clay nacomposites

NASA Astrophysics Data System (ADS)

Cunningham, Andrew

A variety of modified clay minerals have been screened to determine their effectiveness as agents for the production of polystyrene-clay nanocomposites. The n-alkylammonium and n-alkyltrimethylammonium surfactants employed to compatibilise the aluminosilicate layers of the minerals were shown to degrade through a series of stages and mechanisms to yield a hydrocarbon product mixture consisting of a homologous series of saturated and unsaturated hydrocarbons, also, the dehydrocyclisation (DHC) of fragmented alkyl chains was shown to lead to the production of various ring compounds which included substituted cycloalkenes, benzene and toluene.The thermal stability of various cation exchanged modification treatments have been analysed. These organoclays have been characterised by XRD, TGA and TG-MS. The evolved gas analysis conducted by TG-MS was employed to identify which products were being thermally desorbed under thermal events previously seen when using TGA. In particular attention was paid to the activity of these materials with respect to the formation of linear, branched and cyclic aliphatics and aromatics from the feedstock surfactants.Intra-series comparisons of different organoclays showed that as the alkyl chain length of the n-alkylammonium surfactants was increased the concentration of thermal desorption products at approximately 400 °C was also increased. However, characterisation of n-alkyltrimethylammonium exchanged MMT showed that the concentration of thermal desorption products at lower temperatures (approximately 250 °C) increased with alkyl chain length between C[n] = 8 - 16. TG-MS analysis showed that this was mostly due to the DHC of alkyl fragments. These compounds appear to have been largely overlooked in related literature.SWa-1, a clay containing greater concentrations of structural iron, showed higher T[max] values for n-alkylammonium surfactant thermal desorption than similarly exchanged SAz-1. This may be evidence of a current theory that structural iron acts as a radical trap. This is thought to significantly reduce the catalytic activity of the clay's acid sites until higher temperatures. The formulation of polystyrene-clay nanocomposites (PSCNs) by in-situ polymerisation led to various results pertaining to their thermal stability. The relative effectiveness of various initiator species for the production of the most thermally stable PSCNs was AIBN > BPO > SPS > APS > AIBA. Lower radical initiator and organic modifier concentrations led to the production of PSCNs with higher thermal stability. The relative effectiveness of these various organoclays for the production of more thermally stable PSCNs was MCBP-Cn > C15A > C20A " C10A. The preparation method was shown to be effective for producing exfoliated nanocomposites for up to 1 wt% of the various organoclays using AIBN and BPO as initiators. The MCBP-Cn PSCNs remained exfoliated up to 5 wt% , they also showed higher thermal stability when compared with the commercial products, which XRD results showed to remain stacked at organoclay loadings > 1 wt%.A novel one-pot synthesis method for the production of PSCN, by the in-situ polymerisation of PS in the presence of decanamide (an uncharged surfactant) and Na-MMT, was shown to be successful. Whereas, other novel PSCN formulations incorporating N-vinylformamide and the amphoteric surfactant foamtaine SCAB were shown to be encouraging but have, so far, had limited success.In contrast, the analysis of industrially produced unsaturated polyester-clay nanocomposites showed very little increase in the thermal stability of the material. Associated analyses indicated increased dimensional stability of the material, AFM analysis showed that imaging of the clay dispersal was possible by this macroscopic technique. Also, ATR-FTIR analysis of the UPR and UPCN, showed that although not exfoliated the silane modified-MMT had a good synergistic effect on the overall material by reducing the formation of combustion products.The thermal stability and associated studies of kaolin-phenylphosphonic acid (KPPA) complexes was also conducted. PPA was shown to intercalate the kaolin crystal structure forming an expanded phase that exhibited remarkable thermal stability (Tmax = 660 °C). 31P MAS NMR of all the KPPA samples showed three peaks (at +1.2, -3.7 and -7.3 ppm) which represented PPA existing in three non-equivalent bonding states at the kaolin surface. The high thermal stability of these hybrid materials was evident from these studies. This research into the use of covalently bound intercalates in nanocomposite manufacture signifies the necessity for further research.

Transient heat transfer behavior of water spray evaporative cooling on a stainless steel cylinder with structured surface for safety design application in high temperature scenario

NASA Astrophysics Data System (ADS)

Aamir, Muhammad; Liao, Qiang; Hong, Wang; Xun, Zhu; Song, Sihong; Sajid, Muhammad

2017-02-01

High heat transfer performance of spray cooling on structured surface might be an additional measure to increase the safety of an installation against any threat caused by rapid increase in the temperature. The purpose of present experimental study is to explore heat transfer performance of structured surface under different spray conditions and surface temperatures. Two cylindrical stainless steel samples were used, one with pyramid pins structured surface and other with smooth surface. Surface heat flux of 3.60, 3.46, 3.93 and 4.91 MW/m2 are estimated for sample initial average temperature of 600, 700, 800 and 900 °C, respectively for an inlet pressure of 1.0 MPa. A maximum cooling rate of 507 °C/s was estimated for an inlet pressure of 0.7 MPa at 900 °C for structured surface while for smooth surface maximum cooling rate of 356 °C/s was attained at 1.0 MPa for 700 °C. Structured surface performed better to exchange heat during spray cooling at initial sample temperature of 900 °C with a relative increase in surface heat flux by factor of 1.9, 1.56, 1.66 and 1.74 relative to smooth surface, for inlet pressure of 0.4, 0.7, 1.0 and 1.3 MPa, respectively. For smooth surface, a decreasing trend in estimated heat flux is observed, when initial sample temperature was increased from 600 to 900 °C. Temperature-based function specification method was utilized to estimate surface heat flux and surface temperature. Limited published work is available about the application of structured surface spray cooling techniques for safety of stainless steel structures at very high temperature scenario such as nuclear safety vessel and liquid natural gas storage tanks.

Analysis of relationships between land surface temperature and land use changes in the Yellow River Delta

NASA Astrophysics Data System (ADS)

Ning, Jicai; Gao, Zhiqiang; Meng, Ran; Xu, Fuxiang; Gao, Meng

2018-06-01

This study analyzed land use and land cover changes and their impact on land surface temperature using Landsat 5 Thematic Mapper and Landsat 8 Operational Land Imager and Thermal Infrared Sensor imagery of the Yellow River Delta. Six Landsat images comprising two time series were used to calculate the land surface temperature and correlated vegetation indices. The Yellow River Delta area has expanded substantially because of the deposited sediment carried from upstream reaches of the river. Between 1986 and 2015, approximately 35% of the land use area of the Yellow River Delta has been transformed into salterns and aquaculture ponds. Overall, land use conversion has occurred primarily from poorly utilized land into highly utilized land. To analyze the variation of land surface temperature, a mono-window algorithm was applied to retrieve the regional land surface temperature. The results showed bilinear correlation between land surface temperature and the vegetation indices (i.e., Normalized Difference Vegetation Index, Adjusted-Normalized Vegetation Index, Soil-Adjusted Vegetation Index, and Modified Soil-Adjusted Vegetation Index). Generally, values of the vegetation indices greater than the inflection point mean the land surface temperature and the vegetation indices are correlated negatively, and vice versa. Land surface temperature in coastal areas is affected considerably by local seawater temperature and weather conditions.

Phonons on fcc (100), (110), and (111) surfaces using Lennard-Jones potentials. II. Temperature dependence of surface phonons studied with molecular dynamics

NASA Astrophysics Data System (ADS)

Koleske, D. D.; Sibener, S. J.

In this paper we present temperature dependent studies of the surface phonon dispersion relations for fcc (100), (110), and (111) faces using molecular dynamics (MD) simulations and Lennard-Jones potentials. This study was conducted in order to investigate how anharmonic potential terms influence the dynamical properties of the surface. This was accomplished by examining the temperature dependence of the Q-resolved phonon spectral density function. All phonon frequencies were found to decrease linearly in T as the temperature was increased, while at low temperatures the phonon linewidths increased linearly with T. At higher temperatures, some of the phonon linewidths changed from having a linear to a quadratic dependence on T. The temperature at which this T to T2 change occurs is surface dependent and occurs at the lowest temperature on the (110) surface. The T2 dependence arises from the increasing importance of higher-order phonon-phonon scattering terms. The phonons which exhibit T2 dependence tend to be modes which propagate perpendicularly or nearly perpendicularly to the direction of maximum root-mean-squared displacement (RMSD). This is especially true for the linewidth of the S 1 mode at overlineX on the (110) surface where, at T ≈ 15-23% of the melting temperature, the RMSD perpendicular to the atomic rows become larger than the RMSD normal to the surface. Our results indicate that the dynamics on the (110) surface may be significantly influenced by anharmonic potential terms at temperatures as low as 15% of the melting temperature.

Titan Surface Temperatures as Measured by Cassini CIRS

NASA Technical Reports Server (NTRS)

Jennings, Donald E.; Flasar, F.M.; Kunde, V.G.; Nixon, C.A.; Romani, P.N.; Samuelson, R.E.; Coustenis, A.; Courtin, R.

2009-01-01

Thermal radiation from the surface of Titan reaches space through a spectral window of low opacity at 19-microns wavelength. This radiance gives a measure of the brightness temperature of the surface. Composite Infrared Spectrometer' (CIRS) observations from Cassini during its first four years at Saturn have permitted latitude mapping of zonally averaged surface temperatures. The measurements are corrected for atmospheric opacity using the dependence of radiance on emission angle. With the more complete latitude coverage and much larger dataset of CIRS we have improved upon the original results from Voyager IRIS. CIRS measures the equatorial surface brightness temperature to be 93.7+/-0.6 K, the same as the temperature measured at the Huygens landing site. The surface brightness temperature decreases by 2 K toward the south pole and by 3 K toward the north pole. The drop in surface temperature between equator and north pole implies a 50% decrease in methane saturation vapor pressure and relative humidity; this may help explain the large northern lakes. The H2 mole fraction is derived as a by-product of our analysis and agrees with previous results. Evidence of seasonal variation in surface and atmospheric temperatures is emerging from CIRS measurements over the Cassini mission.

Estimating morning changes in land surface temperature from MODIS day/night land surface temperature: Applications for surface energy balance modeling

USDA-ARS?s Scientific Manuscript database

Observations of land surface temperature (LST) are crucial for the monitoring of surface energy fluxes from satellite. Methods that require high temporal resolution LST observations (e.g., from geostationary orbit) can be difficult to apply globally because several geostationary sensors are required...

High frequency thermal emission from the lunar surface and near surface temperature of the Moon from Chang’E-2 microwave radiometer

NASA Astrophysics Data System (ADS)

Fang, Tuo; Fa, Wenzhe

2014-04-01

Near surface temperature of the Moon and thermal behaviors of the lunar regolith can provide important information for constraining thermal and magmatic evolution models of the Moon and engineering constrains for in situ lunar exploration system. In this study, China’s Chang’E-2 (CE-2) microwave radiometer (MRM) data at high frequency channels are used to investigate near surface temperature of the Moon given the penetration ability of microwave into the desiccated and porous lunar regolith. Factors that affect high frequency brightness temperature (TB), such as surface slope, solar albedo and dielectric constant, are analyzed first using a revised Racca’s temperature model. Radiative transfer theory is then used to model thermal emission from a semi-infinite regolith medium, with considering dielectric constant and temperature profiles within the regolith layer. To decouple the effect of diurnal temperature variation in the uppermost lunar surface, diurnal averaged brightness temperatures at high frequency channels are used to invert mean diurnal surface and subsurface temperatures based on their bilinear profiles within the regolith layer. Our results show that, at the scale of the spatial resolution of CE-2 MRM, surface slope of crater wall varies typically from about 20° to 30°, and this causes a variation in TB about 10-15 K. Solar albedo can give rise to a TB difference of about 5-10 K between maria and highlands, whereas a ∼2-8 K difference can be compensated by the dielectric constant on the other hand. Inversion results indicate that latitude (ϕ) variations of the mean diurnal surface and subsurface temperatures follow simple rules as cos0.30ϕ and cos0.36ϕ, respectively. The inverted mean diurnal temperature profiles at the Apollo 15 and 17 landing sites are also compared with the Apollo heat flow experiment data, showing an inversion uncertainty <4 K for surface temperature and <1 K for subsurface temperature.

Identifying anthropogenic anomalies in air, surface and groundwater temperatures in Germany.

PubMed

Benz, Susanne A; Bayer, Peter; Blum, Philipp

2017-04-15

Human activity directly influences ambient air, surface and groundwater temperatures. The most prominent phenomenon is the urban heat island effect, which has been investigated particularly in large and densely populated cities. This study explores the anthropogenic impact on the thermal regime not only in selected urban areas, but on a countrywide scale for mean annual temperature datasets in Germany in three different compartments: measured surface air temperature, measured groundwater temperature, and satellite-derived land surface temperature. Taking nighttime lights as an indicator of rural areas, the anthropogenic heat intensity is introduced. It is applicable to each data set and provides the difference between measured local temperature and median rural background temperature. This concept is analogous to the well-established urban heat island intensity, but applicable to each measurement point or pixel of a large, even global, study area. For all three analyzed temperature datasets, anthropogenic heat intensity grows with increasing nighttime lights and declines with increasing vegetation, whereas population density has only minor effects. While surface anthropogenic heat intensity cannot be linked to specific land cover types in the studied resolution (1km×1km) and classification system, both air and groundwater show increased heat intensities for artificial surfaces. Overall, groundwater temperature appears most vulnerable to human activity, albeit the different compartments are partially influenced through unrelated processes; unlike land surface temperature and surface air temperature, groundwater temperatures are elevated in cultivated areas as well. At the surface of Germany, the highest anthropogenic heat intensity with 4.5K is found at an open-pit lignite mine near Jülich, followed by three large cities (Munich, Düsseldorf and Nuremberg) with annual mean anthropogenic heat intensities >4K. Overall, surface anthropogenic heat intensities >0K and therefore urban heat islands are observed in communities down to a population of 5000. Copyright © 2017 Elsevier B.V. All rights reserved.

Some Physical and Computational Issues in Land Surface Data Assimilation of Satellite Skin Temperatures

NASA Astrophysics Data System (ADS)

Mackaro, Scott M.; McNider, Richard T.; Biazar, Arastoo Pour

2012-03-01

Skin temperatures that reflect the radiating temperature of a surface observed by infrared radiometers are one of the most widely available products from polar orbiting and geostationary satellites and the most commonly used satellite data in land surface assimilation. Past work has indicated that a simple land surface scheme with a few key parameters constrained by observations such as skin temperatures may be preferable to complex land use schemes with many unknown parameters. However, a true radiating skin temperature is sometimes not a prognostic variable in weather forecast models. Additionally, recent research has shown that skin temperatures cannot be directly used in surface similarity forms for inferring fluxes. This paper examines issues encountered in using satellite derived skin temperatures to improve surface flux specifications in weather forecast and air quality models. Attention is given to iterations necessary when attempting to nudge the surface energy budget equation to a desired state. Finally, the issue of mathematical operator splitting is examined in which the surface energy budget calculations are split with the atmospheric vertical diffusion calculations. However, the high level of connectivity between the surface and first atmospheric level means that the operator splitting leads to high frequency oscillations. These oscillations may hinder the assimilation of skin temperature derived moisture fluxes.

Evolution of surface sensible heat over the Tibetan Plateau under the recent global warming hiatus

NASA Astrophysics Data System (ADS)

Zhu, Lihua; Huang, Gang; Fan, Guangzhou; Qu, Xia; Zhao, Guijie; Hua, Wei

2017-10-01

Based on regular surface meteorological observations and NCEP/DOE reanalysis data, this study investigates the evolution of surface sensible heat (SH) over the central and eastern Tibetan Plateau (CE-TP) under the recent global warming hiatus. The results reveal that the SH over the CE-TP presents a recovery since the slowdown of the global warming. The restored surface wind speed together with increased difference in ground-air temperature contribute to the recovery in SH. During the global warming hiatus, the persistent weakening wind speed is alleviated due to the variation of the meridional temperature gradient. Meanwhile, the ground surface temperature and the difference in ground-air temperature show a significant increasing trend in that period caused by the increased total cloud amount, especially at night. At nighttime, the increased total cloud cover reduces the surface effective radiation via a strengthening of atmospheric counter radiation and subsequently brings about a clear upward trend in ground surface temperature and the difference in ground-air temperature. Cloud-radiation feedback plays a significant role in the evolution of the surface temperature and even SH during the global warming hiatus. Consequently, besides the surface wind speed, the difference in ground-air temperature becomes another significant factor for the variation in SH since the slowdown of global warming, particularly at night.

Comparison of Observed Surface Temperatures of 4 Vesta to the KRC Thermal Model

NASA Technical Reports Server (NTRS)

Titus, T. N.; Becker, K. J.; Anderson, J. A.; Capria, M. T.; Tosi, F.; DeSanctis, M. C.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.;

Reentry heating analysis of space shuttle with comparison of flight data

NASA Technical Reports Server (NTRS)

Gong, L.; Quinn, R. D.; Ko, W. L.

1982-01-01

Surface heating rates and surface temperatures for a space shuttle reentry profile were calculated for two wing cross sections and one fuselage cross section. Heating rates and temperatures at 12 locations on the wing and 6 locations on the fuselage are presented. The heating on the lower wing was most severe, with peak temperatures reaching values of 1240 C for turbulent flow and 900 C for laminar flow. For the fuselage, the most severe heating occured on the lower glove surface where peak temperatures of 910 C and 700 C were calculated for turbulent flow and laminar flow, respectively. Aluminum structural temperatures were calculated using a finite difference thermal analyzer computer program, and the predicted temperatures are compared to measured flight data. Skin temperatures measured on the lower surface of the wing and bay 1 of the upper surface of the wing agreed best with temperatures calculated assuming laminar flow. The measured temperatures at bays two and four on the upper surface of the wing were in quite good agreement with the temperatures calculated assuming separated flow. The measured temperatures on the lower forward spar cap of bay four were in good agreement with values predicted assuming laminar flow.

Antarctic Surface Temperatures Using Satellite Infrared Data from 1979 Through 1995

NASA Technical Reports Server (NTRS)

Comiso, Josefino C.; Stock, Larry

1997-01-01

The large scale spatial and temporal variations of surface ice temperature over the Antarctic region are studied using infrared data derived from the Nimbus-7 Temperature Humidity Infrared Radiometer (THIR) from 1979 through 1985 and from the NOAA Advanced Very High Resolution Radiometer (AVHRR) from 1984 through 1995. Enhanced techniques suitable for the polar regions for cloud masking and atmospheric correction were used before converting radiances to surface temperatures. The observed spatial distribution of surface temperature is highly correlated with surface ice sheet topography and agrees well with ice station temperatures with 2K to 4K standard deviations. The average surface ice temperature over the entire continent fluctuates by about 30K from summer to winter while that over the Antarctic Plateau varies by about 45K. Interannual fluctuations of the coldest interannual variations in surface temperature are highest at the Antarctic Plateau and the ice shelves (e.g., Ross and Ronne) with a periodic cycle of about 5 years and standard deviations of about 11K and 9K, respectively. Despite large temporal variability, however, especially in some regions, a regression analysis that includes removal of the seasonal cycle shows no apparent trend in temperature during the period 1979 through 1995.

Effective surface Debye temperature for NiMnSb(100) epitaxial films

NASA Astrophysics Data System (ADS)

Borca, C. N.; Komesu, Takashi; Jeong, Hae-kyung; Dowben, P. A.; Ristoiu, D.; Hordequin, Ch.; Pierre, J.; Nozières, J. P.

2000-07-01

The surface Debye temperature of the NiMnSb (100) epitaxial films has been obtained using low energy electron diffraction, inverse photoemission, and core-level photoemission. The normal dynamic motion of the (100) surface results in a value for the effective surface Debye temperature of 145±13 K. This is far smaller than the bulk Debye temperature of 312±5 K obtained from wave vector dependent inelastic neutron scattering. The large difference between these measures of surface and bulk dynamic motion indicates a soft and compositionally different (100) surface.

Decay assessment through thermographic analysis in architectural and archaeological heritage

NASA Astrophysics Data System (ADS)

Gomez-Heras, Miguel; Martinez-Perez, Laura; Fort, Rafael; Alvarez de Buergo, Monica

2010-05-01

Any exposed stone-built structure is subject to thermal variations due to daily, seasonal and secular environmental temperature changes. Surface temperature is a function of air temperature (due to convective heat transfer) and of infrared radiation received through insolation. While convective heat transfer homogenizes surface temperature, stone response to insolation is much more complex and the temporal and spatial temperature differences across structures are enhanced. Surface temperature in stone-built structures will be affected by orientation, sunlight inclination and the complex patterns of light and shadows generated by the often intricate morphology of historical artefacts and structures. Surface temperature will also be affected by different material properties, such as albedo, thermal conductivity, transparency and absorbance to infrared radiation of minerals and rocks. Moisture and the occurrence of salts will also be a factor affecting surface temperatures. Surface temperatures may as well be affected by physical disruptions of rocks due to differences in thermal inertia generated by cracks and other discontinuities. Thermography is a non-invasive, non-destructive technique that measures temperature variations on the surface of a material. With this technique, surface temperature rates of change and their spatial variations can be analysed. This analysis may be used not only to evaluate the incidence of thermal decay as a factor that generates or enhances stone decay, but also to detect and evaluate other factors that affect the state of conservation of architectural and archaeological heritage, as for example moisture, salts or mechanical disruptions.

Physical Retrieval of Surface Emissivity Spectrum from Hyperspectral Infrared Radiances

NASA Technical Reports Server (NTRS)

Li, Jun; Weisz, Elisabeth; Zhou, Daniel K.

2007-01-01

Retrieval of temperature, moisture profiles and surface skin temperature from hyperspectral infrared (IR) radiances requires spectral information about the surface emissivity. Using constant or inaccurate surface emissivities typically results in large retrieval errors, particularly over semi-arid or arid areas where the variation in emissivity spectrum is large both spectrally and spatially. In this study, a physically based algorithm has been developed to retrieve a hyperspectral IR emissivity spectrum simultaneously with the temperature and moisture profiles, as well as the surface skin temperature. To make the solution stable and efficient, the hyperspectral emissivity spectrum is represented by eigenvectors, derived from the laboratory measured hyperspectral emissivity database, in the retrieval process. Experience with AIRS (Atmospheric InfraRed Sounder) radiances shows that a simultaneous retrieval of the emissivity spectrum and the sounding improves the surface skin temperature as well as temperature and moisture profiles, particularly in the near surface layer.

Influence of free surface curvature on the Pearson instability in Marangoni convection

NASA Astrophysics Data System (ADS)

Hu, W. R.

The Peason instability in a liquid layer bounded by a plate solid boundary with higher constant temperature and a plane free surface with lower constant temperatures in the microgravity environment has by extensively studied The free surface in the microgravity environment tends to be curved in general as a spherical shape and the plane configuration of free surface is a special case In the present paper a system of liquid layer bounded by a plat solid boundary with higher constant temperature and a curved free surface with lower non-uniform temperature is studied The temperature gradient on the free surface will induce the thermocapillary convection and the onset of Marangoni convection is coupled with the thermocapillary convection The thermocapillary convection induced by the temperature gradient on the curved free surface and its influence on the Marangoni convection are studied in the present paper

30 CFR 36.48 - Tests of surface temperature of engine and components of the cooling system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Tests of surface temperature of engine and... temperature of engine and components of the cooling system. (a) The surface temperatures of the engine... components shall have reached their respective equilibrium temperatures. The exhaust cooling system shall be...

30 CFR 36.48 - Tests of surface temperature of engine and components of the cooling system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Tests of surface temperature of engine and... temperature of engine and components of the cooling system. (a) The surface temperatures of the engine... components shall have reached their respective equilibrium temperatures. The exhaust cooling system shall be...

30 CFR 36.48 - Tests of surface temperature of engine and components of the cooling system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Tests of surface temperature of engine and... temperature of engine and components of the cooling system. (a) The surface temperatures of the engine... components shall have reached their respective equilibrium temperatures. The exhaust cooling system shall be...

A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009

PubMed Central

Sharma, Sapna; Gray, Derek K; Read, Jordan S; O’Reilly, Catherine M; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie E; Hook, Simon; Lenters, John D; Livingstone, David M; McIntyre, Peter B; Adrian, Rita; Allan, Mathew G; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John; Baron, Jill S; Brookes, Justin; Chen, Yuwei; Daly, Robert; Dokulil, Martin; Dong, Bo; Ewing, Kye; de Eyto, Elvira; Hamilton, David; Havens, Karl; Haydon, Shane; Hetzenauer, Harald; Heneberry, Jocelyne; Hetherington, Amy L; Higgins, Scott N; Hixson, Eric; Izmest’eva, Lyubov R; Jones, Benjamin M; Kangur, Külli; Kasprzak, Peter; Köster, Olivier; Kraemer, Benjamin M; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Müller-Navarra, Dörthe; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Niederhauser, Pius; North, Ryan P; Paterson, Andrew M; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars; Rusak, James A; Salmaso, Nico; Samal, Nihar R; Schindler, Daniel E; Schladow, Geoffrey; Schmidt, Silke R; Schultz, Tracey; Silow, Eugene A; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A; Williamson, Craig E; Woo, Kara H

2015-01-01

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues. PMID:25977814

A global database of lake surface temperatures collected by in situ and satellite methods from 1985-2009.

PubMed

Sharma, Sapna; Gray, Derek K; Read, Jordan S; O'Reilly, Catherine M; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie E; Hook, Simon; Lenters, John D; Livingstone, David M; McIntyre, Peter B; Adrian, Rita; Allan, Mathew G; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John; Baron, Jill S; Brookes, Justin; Chen, Yuwei; Daly, Robert; Dokulil, Martin; Dong, Bo; Ewing, Kye; de Eyto, Elvira; Hamilton, David; Havens, Karl; Haydon, Shane; Hetzenauer, Harald; Heneberry, Jocelyne; Hetherington, Amy L; Higgins, Scott N; Hixson, Eric; Izmest'eva, Lyubov R; Jones, Benjamin M; Kangur, Külli; Kasprzak, Peter; Köster, Olivier; Kraemer, Benjamin M; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Müller-Navarra, Dörthe; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Niederhauser, Pius; North, Ryan P; Paterson, Andrew M; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars; Rusak, James A; Salmaso, Nico; Samal, Nihar R; Schindler, Daniel E; Schladow, Geoffrey; Schmidt, Silke R; Schultz, Tracey; Silow, Eugene A; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A; Williamson, Craig E; Woo, Kara H

2015-01-01

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985-2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.

A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009

USGS Publications Warehouse

Sharma, Sapna; Gray, Derek; Read, Jordan S.; O'Reilly, Catherine; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie; Hook, Simon; Lenters, John; Livingstone, David M.; McIntyre, Peter B.; Adrian, Rita; Allan, Mathew; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John E.; Baron, Jill S.; Brookes, Justin D; Chen, Yuwei; Daly, Robert; Ewing, Kye; de Eyto, Elvira; Dokulil, Martin; Hamilton, David B.; Havens, Karl; Haydon, Shane; Hetzenaeur, Harald; Heneberry, Jocelyn; Hetherington, Amy; Higgins, Scott; Hixson, Eric; Izmest'eva, Lyubov; Jones, Benjamin M.; Kangur, Kulli; Kasprzak, Peter; Kraemer, Benjamin; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Dörthe Müller-Navarra,; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Pius Niederhauser,; North, Ryan P.; Andrew Paterson,; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars G.; Rusak, James A.; Salmaso, Nico; Samal, Nihar R.; Daniel E. Schindler,; Geoffrey Schladow,; Schmidt, Silke R.; Tracey Schultz,; Silow, Eugene A.; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A.; Craig E. Williamson,; Kara H. Woo,

2015-01-01

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.

Asteroid Impacts, Microbes, and the Cooling of the Atmosphere

NASA Technical Reports Server (NTRS)

Oberbeck, Verne R.; Mancinelli, Rocco L.

1994-01-01

Earth's surface temperature constrained microbial evolution, according to Schwartzman et al. (1993). Their hypothesis states that the maximal temperature that extant organisms of a given type tolerate is the surface temperature occurring when that type of organism arose. Schwartzman and his colleagues concluded that the temperature changed from 100 C to 50 C between 3.75 billion years ago (BYA) and 1 BYA. These temperatures are consistent with those derived from oxygen isotope ratios in ancient sediments (Karhu and Epstein 1986, Knauth and Lowe 1978). The 100 C surface temperature they derive for 3.75 BYA is also the same as Earth's surface temperature 4.4 BYA (Kosting and Ackerman 1986). In this article, we address the cause of the delay in surface cooling until 3.75 BYA, and we explore the implications for microbial evolution of a high temperature on early Earth. We propose that three effects of the early heavy bombardment of Earth by asteroids and comets, until 3.8 BYA, could have delayed onset of surface cooling.

Elastohydrodynamic principles applied to the design of helicopter components.

NASA Technical Reports Server (NTRS)

Townsend, D. P.

1973-01-01

Elastohydrodynamic principles affecting the lubrication of transmission components are presented and discussed. Surface temperatures of the transmission bearings and gears affect elastohydrodynamic film thickness. Traction forces and sliding as well as the inlet temperature determine surface temperatures. High contact ratio gears cause increased sliding and may run at higher surface temperatures. Component life is a function of the ratio of elastohydrodynamic film thickness to composite surface roughness. Lubricant starvation reduces elastohydrodynamic film thickness and increases surface temperatures. Methods are presented which allow for the application of elastohydrodynamic principles to transmission design in order to increase system life and reliability.

Elastohydrodynamic principles applied to the design of helicopter components

NASA Technical Reports Server (NTRS)

Townsend, D. P.

1973-01-01

Elastohydrodynamic principles affecting the lubrication of transmission components are presented and discussed. Surface temperature of the transmission bearings and gears affect elastohydrodynamic film thickness. Traction forces and sliding as well as the inlet temperature determine surface temperatures. High contact ratio gears cause increased sliding and may run at higher surface temperatures. Component life is a function of the ratio of elastohydrodynamic film thickness to composite surface roughness. Lubricant starvation reduces elastrohydrodynamic film thickness and increases surface temperatures. Methods are presented which allow for the application of elastohydrodynamic principles to transmission design in order to increase system life and reliability.

Sputter ripples and radiation-enhanced surface kinetics on Cu(001)

NASA Astrophysics Data System (ADS)

Chan, Wai Lun; Chason, Eric

2005-10-01

We have measured the temperature and flux dependence of the wavelength of surface ripples spontaneously formed by low-energy sputtering of a Cu(001) surface. We find that the temperature dependence of the ripple wavelength is non-Arrhenius, with a greater apparent activation at high temperature than at low temperature. Furthermore, the dependence of the wavelength on flux changes significantly with temperature. In the high-temperature regime, the wavelength decreases as the ion flux increases, while at low temperature, the wavelength is essentially independent of flux. We explain these results by a quantitative model that includes the mechanisms controlling the concentration of mobile defects on the surface in the two temperature regimes. At low temperature, mobile defects are induced by the ion beam while at higher temperature, the defects are thermally generated.

Modelling of surface-water temperature for the estimation of the Czech fishery productivity under the climate change

NASA Astrophysics Data System (ADS)

Svobodová, Eva; Trnka, Miroslav; Kopp, Radovan; Mareš, Jan; Dubrovský, Martin; Spurný, Petr; Žalud, Zděněk

2015-04-01

Freshwater fish production is significantly correlated with water temperature which is expected to increase under the climate change. This study is dealing with the estimation of the change of water temperature in productive ponds and its impact on the fishery in the Czech Republic. Calculation of surface-water temperature which was based on three-day mean of the air temperature was developed and tested in several ponds in three main fish production areas. Output of surface-water temperature model was compared with measured data and showed that the lower range of model accuracy is surface-water temperature 3°C, under this temperature threshold the model loses its predictive competence. In the expecting of surface-water temperature above the temperature 3°C the model has proved the well consistence between observed and modelled surface-water temperature (R 0.79 - 0.96). Verified model was applied in the conditions of climate change determined by the pattern scaling method, in which standardised scenarios were derived from five global circulation models MPEH5, CSMK3, IPCM4, GFCM21 and HADGEM. Results were evaluated with regard to thresholds which characterise the fish species requirements on water temperature. Used thresholds involved the upper temperature threshold for fish survival and the tolerable number of days in continual period with mentioned threshold surface-water temperature. Target fish species were Common carp (Cyprinus carpio), Maraene whitefish (Coregonus maraena), Northern whitefish (Coregonus peled) and Rainbow trout (Oncorhynchus mykis). Results indicated the limitation of the Czech fish-farming in terms of i) the increase of the length of continual periods with surface-water temperature above the threshold appropriate to given fish species toleration, ii) the increase of the number of continual periods with surface-water temperature above the threshold, both appropriate to given fish species toleration, and iii) the increase of overall number of days within the continual period with temperature above the threshold tolerated by given fish species. ACKNOWLEDGEMENTS: This study was funded by project "Building up a multidisciplinary scientific team focused on drought" No. CZ.1.07/2.3.00/20.0248.

Rapid control of mold temperature during injection molding process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liparoti, Sara; Titomanlio, Giuseppe; Hunag, Tsang Min

2015-05-22

The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during themore » entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.« less

Temperature effects on the atomic structure and kinetics in single crystal electrochemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gründer, Yvonne; Markovic, Nenad M.; Thompson, Paul

2015-01-01

The influence of temperature on the atomic structure at the electrochemical interface has been studied using in-situ surface x-ray scattering (SXS) during the formation of metal monolayers on a Au(111) electrode. For the surface reconstruction of Au(111), higher temperatures increase the mobility of surface atoms in the unreconstructed phase which then determines the surface ordering during the formation of the reconstruction. For the underpotential deposition (UPD) systems, the surface diffusion of the depositing metal adatoms is significantly reduced at low temperatures which results in the frustration of ordered structures in the case of Cu UPD, occurring on a Br-modified surface,more » and in the formation of a disordered Ag monolayer during Ag UPD. The results indicate that temperature changes affect the mass transport and diffusion of metal adatoms on the electrode surface. This demonstrates the importance of including temperature as a variable in studying surface structure and reactions at the electrochemical interface.« less

Evaluation of a surface/vegetation parameterization using satellite measurements of surface temperature

NASA Technical Reports Server (NTRS)

Taconet, O.; Carlson, T.; Bernard, R.; Vidal-Madjar, D.

1986-01-01

Ground measurements of surface-sensible heat flux and soil moisture for a wheat-growing area of Beauce in France were compared with the values derived by inverting two boundary layer models with a surface/vegetation formulation using surface temperature measurements made from NOAA-AVHRR. The results indicated that the trends in the surface heat fluxes and soil moisture observed during the 5 days of the field experiment were effectively captured by the inversion method using the remotely measured radiative temperatures and either of the two boundary layer methods, both of which contain nearly identical vegetation parameterizations described by Taconet et al. (1986). The sensitivity of the results to errors in the initial sounding values or measured surface temperature was tested by varying the initial sounding temperature, dewpoint, and wind speed and the measured surface temperature by amounts corresponding to typical measurement error. In general, the vegetation component was more sensitive to error than the bare soil model.

Modeling sea-surface temperature and its variability

NASA Technical Reports Server (NTRS)

Sarachik, E. S.

1985-01-01

A brief review is presented of the temporal scales of sea surface temperature variability. Progress in modeling sea surface temperature, and remaining obstacles to the understanding of the variability is discussed.

The effect of intestinal bacteria adherence on drug diffusion through solid films under stationary conditions.

PubMed

Rubinstein, A; Radai, R; Friedman, M; Fischer, P; Rokem, J S

1997-04-01

To study the in vitro and in vivo the role of surface bacterial adhesion on the diffusion of model drugs at stationary conditions. Salicylic acid (SA) diffusion through ethyl cellulose (EC) films was measured in vitro in side-by-side diffusion cells with and without E. coli of intestinal origin. Insulin (I) release from paper strips coated or uncoated with pectin films, with or without antibiotic treatment, was measured in vivo in conscious rats after cecal implantation by comparing blood glucose levels at Tmax of the pharmacodynamic effect. During five hours of diffusion studies which were performed immediately following incubation of EC films with bacteria, the diffusion rate of SA throughout the films was 2.72-fold lower in the presence of bacteria compared with the diffusion rate in the control studies conducted without bacteria. The mean blood glucose levels dropped in the rat to 40.6 +/- 21.6% of glucose basal levels within 2.4 +/- 1.4 h when uncoated I solid carriers were used. Glucose levels did not change for pectin-coated dosage forms. After antibiotic treatment which prevented the formation of bacterial biofilm on the surface of the I solid dosage forms, blood glucose levels dropped to 22.0 +/- 4.7% and 50.9 +/- 20.5% of glucose basal levels within 7.4 +/- 2.6 h and 1.8 +/- 0.9 h for pectin uncoated or coated dosage forms, respectively. Maximum bacterial adherence occurred at stationary conditions (RPM = 0), while at maximum agitation (200 RPM), almost no adherence occurred. (a) Bacterial adherence shows down the diffusion rate of SA through EC films; (b) Under stationary conditions bacterial adherence may also interfere with drug release from biodegradable (pectin) films; (c) Successful functioning of biodegradable colon-specific delivery systems depends on agitation and surface friction in the lumen of the colon.

Method for making mirrored surfaces comprising superconducting material

DOEpatents

Early, J.T.; Hargrove, R.S.

1989-12-12

Superconducting mirror surfaces are provided by forming a mirror surface from a material which is superconductive at a temperature above about 40 K and adjusting the temperature of the surface to that temperature at which the material is superconducting. The mirror surfaces are essentially perfect reflectors for electromagnetic radiation with photon energy less than the superconducting band gap.

Utilization of Satellite Data in Land Surface Hydrology: Sensitivity and Assimilation

NASA Technical Reports Server (NTRS)

Lakshmi, Venkataraman; Susskind, Joel

1999-01-01

This paper investigates the sensitivity of potential evapotranspiration to input meteorological variables, viz- surface air temperature and surface vapor pressure. The sensitivity studies have been carried out for a wide range of land surface variables such as wind speed, leaf area index and surface temperatures. Errors in the surface air temperature and surface vapor pressure result in errors of different signs in the computed potential evapotranspiration. This result has implications for use of estimated values from satellite data or analysis of surface air temperature and surface vapor pressure in large scale hydrological modeling. The comparison of cumulative potential evapotranspiration estimates using ground observations and satellite observations over Manhattan, Kansas for a period of several months shows very little difference between the two. The cumulative differences between the ground based and satellite based estimates of potential evapotranspiration amounted to less that 20mm over a 18 month period and a percentage difference of 15%. The use of satellite estimates of surface skin temperature in hydrological modeling to update the soil moisture using a physical adjustment concept is studied in detail including the extent of changes in soil moisture resulting from the assimilation of surface skin temperature. The soil moisture of the surface layer is adjusted by 0.9mm over a 10 day period as a result of a 3K difference between the predicted and the observed surface temperature. This is a considerable amount given the fact that the top layer can hold only 5mm of water.

Maximum of a Fractional Brownian Motion: Analytic Results from Perturbation Theory.

PubMed

Delorme, Mathieu; Wiese, Kay Jörg

2015-11-20

Fractional Brownian motion is a non-Markovian Gaussian process X_{t}, indexed by the Hurst exponent H. It generalizes standard Brownian motion (corresponding to H=1/2). We study the probability distribution of the maximum m of the process and the time t_{max} at which the maximum is reached. They are encoded in a path integral, which we evaluate perturbatively around a Brownian, setting H=1/2+ϵ. This allows us to derive analytic results beyond the scaling exponents. Extensive numerical simulations for different values of H test these analytical predictions and show excellent agreement, even for large ϵ.

Controllable Broadband Optical Transparency and Wettability Switching of Temperature-Activated Solid/Liquid-Infused Nanofibrous Membranes.

PubMed

Manabe, Kengo; Matsubayashi, Takeshi; Tenjimbayashi, Mizuki; Moriya, Takeo; Tsuge, Yosuke; Kyung, Kyu-Hong; Shiratori, Seimei

2016-09-29

Inspired by biointerfaces, such as the surfaces of lotus leaves and pitcher plants, researchers have developed innovative strategies for controlling surface wettability and transparency. In particular, great success has been achieved in obtaining low adhesion and high transmittance via the introduction of a liquid layer to form liquid-infused surfaces. Furthermore, smart surfaces that can change their surface properties according to external stimuli have recently attracted substantial interest. As some of the best-performing smart surface materials, slippery liquid-infused porous surfaces (SLIPSs), which are super-repellent, demonstrate the successful achievement of switchable adhesion and tunable transparency that can be controlled by a graded mechanical stimulus. However, despite considerable efforts, producing temperature-responsive, super-repellent surfaces at ambient temperature and pressure remains difficult because of the use of nonreactive lubricant oil as a building block in previously investigated repellent surfaces. Therefore, the present study focused on developing multifunctional materials that dynamically adapt to temperature changes. Here, we demonstrate temperature-activated solidifiable/liquid paraffin-infused porous surfaces (TA-SLIPSs) whose transparency and control of water droplet movement at room temperature can be simultaneously controlled. The solidification of the paraffin changes the surface morphology and the size of the light-transmission inhibitor in the lubricant layer; as a result, the control over the droplet movement and the light transmittance at different temperatures is dependent on the solidifiable/liquid paraffin mixing ratio. Further study of such temperature-responsive, multifunctional systems would be valuable for antifouling applications and the development of surfaces with tunable optical transparency for innovative medical applications, intelligent windows, and other devices.

Response of water temperatures and stratification to changing climate in three lakes with different morphometry

NASA Astrophysics Data System (ADS)

Magee, Madeline R.; Wu, Chin H.

2017-12-01

Water temperatures and stratification are important drivers for ecological and water quality processes within lake systems, and changes in these with increases in air temperature and changes to wind speeds may have significant ecological consequences. To properly manage these systems under changing climate, it is important to understand the effects of increasing air temperatures and wind speed changes in lakes of different depths and surface areas. In this study, we simulate three lakes that vary in depth and surface area to elucidate the effects of the observed increasing air temperatures and decreasing wind speeds on lake thermal variables (water temperature, stratification dates, strength of stratification, and surface heat fluxes) over a century (1911-2014). For all three lakes, simulations showed that epilimnetic temperatures increased, hypolimnetic temperatures decreased, the length of the stratified season increased due to earlier stratification onset and later fall overturn, stability increased, and longwave and sensible heat fluxes at the surface increased. Overall, lake depth influences the presence of stratification, Schmidt stability, and differences in surface heat flux, while lake surface area influences differences in hypolimnion temperature, hypolimnetic heating, variability of Schmidt stability, and stratification onset and fall overturn dates. Larger surface area lakes have greater wind mixing due to increased surface momentum. Climate perturbations indicate that our larger study lakes have more variability in temperature and stratification variables than the smaller lakes, and this variability increases with larger wind speeds. For all study lakes, Pearson correlations and climate perturbation scenarios indicate that wind speed has a large effect on temperature and stratification variables, sometimes greater than changes in air temperature, and wind can act to either amplify or mitigate the effect of warmer air temperatures on lake thermal structure depending on the direction of local wind speed changes.

Pharmacokinetic Properties of Fostamatinib in Patients With Renal or Hepatic Impairment: Results From 2 Phase I Clinical Studies.

PubMed

Martin, Paul; Oliver, Stuart; Gillen, Michael; Marbury, Thomas; Millson, David

2015-12-01

Phase III trials of fostamatinib, an oral spleen tyrosine kinase inhibitor, in the treatment of rheumatoid arthritis have been completed. Herein, we report the effects of renal and hepatic impairment on the pharmacokinetic (PK) properties of the active metabolite of fostamatinib, R406, in plasma, and on the urinary excretion of R406 and its metabolite N-glucuronide. Two Phase I, single-center, open-label clinical trials determined the PK properties and tolerability of fostamatinib in subjects with normal or impaired renal or hepatic function. Twenty-four subjects in the study in renal impairment (8 per group: normal renal function, moderate renal dysfunction, or end-stage renal disease [ESRD]), and 32 subjects in the study in hepatic impairment (8 per group: normal hepatic function or mild, moderate, or severe hepatic impairment) received a single 150-mg dose of fostamatinib. Patients with ESRD in the study in renal impairment participated in 2 treatment periods separated by a ≥1-week washout. In these patients, fostamatinib was administered after dialysis or 2 hours before dialysis. Geometric mean R406 Cmax and AUC values were less in the combined renally impaired group than in the group with normal renal function; Tmax was similar across groups. However, renal impairment had no apparent effect considered clinically relevant on unbound R406. In patients with ESRD, R406 exposure was less when fostamatinib was administered after compared with before dialysis. Urinary excretion of R406 N-glucuronide was decreased with increasing severity of renal impairment. Renal elimination of R406 was negligible in all groups. Varying degrees of hepatic impairment had no consistent effects on the PK properties of R406. R406 Cmax values were 10% to 15% less in all hepatically impaired groups than in the group with normal hepatic function. AUC and Tmax values were similar between the groups with normal and severely impaired hepatic function; in the groups with mild or moderate hepatic impairment, AUC was less and Tmax was greater. The geometric mean percentage of unbound R406 ranged from 0.64% to 1.95% and was greatest in the group with severe hepatic impairment. The urinary excretion of R406 was minimal. The amount of R406 N-glucuronide excreted in urine was greater in severely hepatically impaired patients. Fostamatinib 150 mg was generally well tolerated. In these patients, renal or hepatic impairment did not affect exposure to the active metabolite of fostamatinib, R406, to a clinically relevant extent. ClinicalTrials.gov identifiers: NCT01245790 (renal) and NCT01222455 (hepatic). Copyright © 2015 Elsevier HS Journals, Inc. All rights reserved.

Impact of food and the proton pump inhibitor rabeprazole on the pharmacokinetics of GDC-0941 in healthy volunteers: bench to bedside investigation of pH-dependent solubility.

PubMed

Ware, Joseph A; Dalziel, Gena; Jin, Jin Y; Pellett, Jackson D; Smelick, Gillian S; West, David A; Salphati, Laurent; Ding, Xiao; Sutton, Rebecca; Fridyland, Jane; Dresser, Mark J; Morrisson, Glenn; Holden, Scott N

2013-11-04

GDC-0941 is an orally administered potent, selective pan-inhibitor of phosphatidylinositol 3-kinases (PI3Ks) with good preclinical antitumor activity in xenograft models and favorable pharmacokinetics and tolerability in phase 1 trials, and it is currently being investigated in phase II clinical trials as an anti-cancer agent. In vitro solubility and dissolution studies suggested that GDC-0941, a weak base, displays significant pH-dependent solubility. Moreover, preclinical studies conducted in famotidine-induced hypochlorhydric dog suggested that the pharmacokinetics of GDC-0941 may be sensitive to pharmacologically induced hypochlorhydria. To investigate the clinical significance of food and pH-dependent solubility on GDC-0941 pharmacokinetics a four-period, two-sequence, open-label, randomized, crossover study was conducted in healthy volunteers. During the fasting state, GDC-0941 was rapidly absorbed with a median Tmax of 2 h. The presence of a high-fat meal delayed the absorption of GDC-0941, with a median Tmax of 4 h and a modest increase in AUC relative to the fasted state, with an estimated geometric mean ratio (GMR, 90% CI) of fed/fasted of 1.28 (1.08, 1.51) for AUC0-∞ and 0.87 (0.70, 1.06) for Cmax. The effect of rabeprazole (model PPI) coadministration on the pharmacokinetics of GDC-0941 was evaluated in the fasted and fed state. When comparing the effect of rabeprazole + GDC-0941 (fasted) to baseline GDC-0941 absorption in a fasted state, GDC-0941 median Tmax was unchanged, however, both Cmax and AUC0-∞ decreased significantly after pretreatment with rabeprazole, with an estimated GMR (90% CI) of 0.31 (0.21, 0.46) and 0.46 (0.35, 0.61), respectively for both parameters. When rabeprazole was administered in the presence of the high-fat meal, the impact of food did not fully reverse the pH effect; the overall effect of rabeprazole on AUC0-∞ was somewhat attenuated by the high-fat meal (estimate GMR of 0.57, with 90% CI, 0.50, 0.65) but unchanged for the Cmax (estimate of 0.43, with 90% CI, 0.37, 0.50). The results of the current investigations emphasize the complex nature of physicochemical interactions and the importance of gastric acid for the dissolution and solubilization processes of GDC-0941. Given these findings, dosing of GDC-0941 in clinical trials was not constrained relative to fasted/fed states, but the concomitant use of ARAs was restricted. Mitigation strategies to limit the influence of pH on exposure of molecularly targeted agents such as GDC-0941 with pH-dependent solubility are discussed.

Ice Surface Temperature Variability in the Polar Regions and the Relationships to 2 Meter Air Temperatures

NASA Astrophysics Data System (ADS)

Hoyer, J.; Madsen, K. S.; Englyst, P. N.

2017-12-01

Determining the surface and near surface air temperature from models or observations in the Polar Regions is challenging due to the extreme conditions and the lack of in situ observations. The errors in near surface temperature products are typically larger than for other regions of the world, and the potential for using Earth Observations is large. As part of the EU project, EUSTACE, we have developed empirical models for the relationship between the satellite observed skin ice temperatures and 2m air temperatures. We use the Arctic and Antarctic Sea and sea ice Surface Temperatures from thermal Infrared satellite sensors (AASTI) reanalysis to estimate daily surface air temperature over land ice and sea ice for the Arctic and the Antarctic. Large efforts have been put into collecting and quality controlling in situ observations from various data portals and research projects. The reconstruction is independent of numerical weather prediction models and thus provides an important alternative to modelled air temperature estimates. The new surface air temperature data record has been validated against more than 58.000 independent in situ measurements for the four surface types: Arctic sea ice, Greenland ice sheet, Antarctic sea ice and Antarctic ice sheet. The average correlations are 92-97% and average root mean square errors are 3.1-3.6°C for the four surface types. The root mean square error includes the uncertainty of the in-situ measurement, which ranges from 0.5 to 2°C. A comparison with ERA-Interim shows a consistently better performance of the satellite based air temperatures than the ERA-Interim for the Greenland ice sheet, when compared against observations not used in any of the two estimates. This is encouraging and demonstrates the values of these products. In addition, the procedure presented here works on satellite observations that are available in near real time and this opens up for a near real time estimation of the surface air temperature over ice from satellites.

Black sea surface temperature anomaly on 5th August 1998 and the ozone layer thickness

NASA Astrophysics Data System (ADS)

Manev, A.; Palazov, K.; Raykov, St.; Ivanov, V.

2003-04-01

BLACK SEA SURFACE TEMPERATURE ANOMALY ON 5th AUGUST 1998 AND THE OZONE LAYER THICKNESS A. Manev , K. Palazov , St. Raykov, V. Ivanov Solar Terrestrial Influences Laboratory, Bulgarian Academy of Sciences amanev@abv.bg This paper focuses on the peculiarities of the Black Sea surface temperature anomaly on 05.08.1998. Researching the daily temperature changes in a number of control fields in the course of 8-10 years, we have found hidden correlations and anomalous deviations in the sea surface temperatures on a global scale. Research proves the statistical reliability of the temperature anomaly on the entire Black Sea surface registered on 04.-05.08.1998. In the course of six days around these dates the temperatures are up to 2°C higher than the maximum temperatures in this period in the other seven years. A more detailed analysis of the dynamics of the anomaly required the investigation of five Black Sea surface characteristic zones of 75x75 km. The analysis covers the period 20 days - 10 days before and 10 days after the anomaly. Investigations aimed at interpreting the reasons for the anomalous heating of the surface waters. We have tried to analyze the correlation between sea surface temperature and the global ozone above the Black Sea by using simultaneously data from the two satellite systems NOAA and TOMS. Methods of processing and comparing the data from the two satellite systems are described. The correlation coefficients values for the five characteristic zones are very high and close, which proves that the character of the correlation ozone - sea surface temperature is the same for the entire Black Sea surface. Despite the high correlation coefficient, we have proved that causality between the two phenomena at the time of the anomaly does not exit.

SO 2-Resistant Immobilized Amine Sorbents for CO 2 Capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tumuluri, Uma

2014-01-01

The solid amine sorbent for CO 2 capture process has advantages of simplicity and low operating cost compared to the MEA (monoethanolamine) process. Solid amine sorbents reported so far suffered from either low CO 2 capture capacity or low stability in the flue gas environment. This project is aimed at developing a SO 2-resistant solid amine sorbent for capturing CO 2 from coal–fired power plants with SCR/FGD which emits SO 2ranging from 15 to 30 ppm and NO ranging from 5 to 10 ppm. The amine sorbent we developed in a previous project degraded rapidly with 65% decrease in themore » initial capture capacity in presence of 1% SO 2. This amine sorbent was further modified by coating with polyethyleneglycol (PEG) to increase the SO 2-resistance. Polyethylene glycol (PEG) was found to decrease the SO 2-amine interaction, resulting in the decrease in the maximum SO desorption temperature (Tmax ) of amine sorbent. The PEG-coated amine sorbent exhibited higher stability with only 40% decrease in the initial capture capacity compared to un-coated amine sorbents. The cost of the solid amine sorbent developed in this project is estimated to be less than $7.00/lb; the sorbent exhibited CO 2 capture capacity more than 2.3 mmol/g. The results of this study provided the scientific basis for further development of SO 2-resistant sorbents.« less

[Pharmacokinetics of crocetin in rats].

PubMed

Liu, Tong-zheng; Qian, Zhi-yu

2002-05-01

To develop an HPLC method for the determination of crocetin in rat plasma and study the pharmacokinetics in rats. Hypersil C18 column (5 microns, 4.6 mm x 200 mm) was used at column temperature 30 degrees C. The mobile phase consisted of methanol-water-acetic acid (75:24.5:0.5) at the flow rate of 1.0 mL.min-1. The UV detection wave length was 423 nm. The calibration curve was linear (gamma = 0.9996) in the range from 0.49 microgram.mL-1 to 7.87 micrograms.mL-1 for crocetin. The mean recovery was 105.2%. The lowest detectable concentration of crocetin was 0.14 microgram.mL-1 (S/N = 3). The RSDs of within-day and between-day were all less than 5%. The plasma crocetin was steady. The HPLC method of determination of crocetin in the plasma was established. After single dose of 50 mg.kg-1 ig in 10 rats, the main pharmacokinetic parameters were estimated as follows: T1/2 alpha (30 +/- 6) min, Tmax(65 +/- 16) min, Cmax(5.0 +/- 1.0) microgram.mL-1, AUC0-T(845 +/- 109) microgram.min.mL-1, Vd(5.0 +/- 0.8) L.kg-1. Crocetin was shown to be absorbed into the blood through the gastrointestinal tract. This method is quick, precise and reliable. Crocetin was shown to be quickly absorbed in rats.

Complete suite of geochemical values computed using wireline logs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lancaster, J.R.; Atkinson, A.

1996-12-31

Geochemical values of {open_quotes}black shale{close_quotes} source rocks can be computed from a complete suite of wireline log data. The computed values are: Total Organic Carbon (Wt%). S1, S2, S3, Hydrogen Index, Oxygen Index, Atomic H/C and O/C ratios, Genetic Potential (S1+S2), S2/S3, and Transfomation Ratio (S1/(S1+S2)). The results are most reliable when calibrated to laboratory analyses of samples in the study area. However, in the absence of samples, reasonable estimates can be made using calibration data from analogous depositional and thermal environments and/or professional judgement and experience. The evaluations provide answers to critical geochemical questions relative to: (1) Organic Mattermore » Quantity; T.O.C. (Wt%), S1, and S2. (2) Kerogen Types; I, II, and III, based on T.O.C. vs S2 cross plot and the van Krevelen diagram of Atomic O/C vs Atomic H/C ratios. (3) Thermal Maturation levels; Transfomation Ratio can be converted to Level of Organic Metamorphism (LOM), pyrolysis Tmax (degC), Vitrinite Reflectance (Ro), Time Temperature Index (TTI) and others. Various analog plots and cross plots can be prepared for interpretation. Case history examples are shown and discussed. Lowstand fan deposits on Barbados were studied in outcrop to construct a conceptual reservoir model for prediction of facies assemblages.« less

Complete suite of geochemical values computed using wireline logs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lancaster, J.R.; Atkinson, A.

1996-01-01

Geochemical values of [open quotes]black shale[close quotes] source rocks can be computed from a complete suite of wireline log data. The computed values are: Total Organic Carbon (Wt%). S1, S2, S3, Hydrogen Index, Oxygen Index, Atomic H/C and O/C ratios, Genetic Potential (S1+S2), S2/S3, and Transfomation Ratio (S1/(S1+S2)). The results are most reliable when calibrated to laboratory analyses of samples in the study area. However, in the absence of samples, reasonable estimates can be made using calibration data from analogous depositional and thermal environments and/or professional judgement and experience. The evaluations provide answers to critical geochemical questions relative to: (1)more » Organic Matter Quantity; T.O.C. (Wt%), S1, and S2. (2) Kerogen Types; I, II, and III, based on T.O.C. vs S2 cross plot and the van Krevelen diagram of Atomic O/C vs Atomic H/C ratios. (3) Thermal Maturation levels; Transfomation Ratio can be converted to Level of Organic Metamorphism (LOM), pyrolysis Tmax (degC), Vitrinite Reflectance (Ro), Time Temperature Index (TTI) and others. Various analog plots and cross plots can be prepared for interpretation. Case history examples are shown and discussed. Lowstand fan deposits on Barbados were studied in outcrop to construct a conceptual reservoir model for prediction of facies assemblages.« less

[Study on Hollow Brick Wall's Surface Temperature with Infrared Thermal Imaging Method].

PubMed

Tang, Ming-fang; Yin, Yi-hua

2015-05-01

To address the characteristic of uneven surface temperature of hollow brick wall, the present research adopts soft wares of both ThermaCAM P20 and ThermaCAM Reporter to test the application of infrared thermal image technique in measuring surface temperature of hollow brick wall, and further analyzes the thermal characteristics of hollow brick wall, and building material's impact on surface temperature distribution including hollow brick, masonry mortar, and so on. The research selects the construction site of a three-story-high residential, carries out the heat transfer experiment, and further examines the exterior wall constructed by 3 different hollow bricks including sintering shale hollow brick, masonry mortar and brick masonry. Infrared thermal image maps are collected, including 3 kinds of sintering shale hollow brick walls under indoor heating in winter; and temperature data of wall surface, and uniformity and frequency distribution are also collected for comparative analysis between 2 hollow bricks and 2 kinds of mortar masonry. The results show that improving heat preservation of hollow brick aid masonry mortar can effectively improve inner wall surface temperature and indoor thermal environment; non-uniformity of surface temperature decreases from 0. 6 to 0. 4 °C , and surface temperature frequency distribution changes from the asymmetric distribution into a normal distribution under the condition that energy-saving sintering shale hollow brick wall is constructed by thermal mortar replacing cement mortar masonry; frequency of average temperature increases as uniformity of surface temperature increases. This research provides a certain basis for promotion and optimization of hollow brick wall's thermal function.

Brillouin-scattering measurements of surface-acoustic-wave velocities in silicon at high temperatures

NASA Astrophysics Data System (ADS)

Stoddart, P. R.; Comins, J. D.; Every, A. G.

1995-06-01

Brillouin-scattering measurements of the angular dependence of surface-acoustic-wave velociites at high temperatures are reported. The measurements have been performed on the (001) surface of a silicon single crystal at temperatures up to 800 °C, allowing comparison of the results with calculated velocities based on existing data for the elastic constants and thermal expansion of silicon in this temperature range. The change in surface-acoustic-wave velocity with temperature is reproduced well, demonstrating the value of this technique for the characterization of the high-temperature elastic properties of opaque materials.

SiGe Based Low Temperature Electronics for Lunar Surface Applications

NASA Technical Reports Server (NTRS)

Mojarradi, Mohammad M.; Kolawa, Elizabeth; Blalock, Benjamin; Cressler, John

2012-01-01

The temperature at the permanently shadowed regions of the moon's surface is approximately -240 C. Other areas of the lunar surface experience temperatures that vary between 120 C and -180 C during the day and night respectively. To protect against the large temperature variations of the moon surface, traditional electronics used in lunar robotics systems are placed inside a thermally controlled housing which is bulky, consumes power and adds complexity to the integration and test. SiGe Based electronics have the capability to operate over wide temperature range like that of the lunar surface. Deploying low temperature SiGe electronics in a lander platform can minimize the need for the central thermal protection system and enable the development of a new generation of landers and mobility platforms with highly efficient distributed architecture. For the past five years a team consisting of NASA, university and industry researchers has been examining the low temperature and wide temperature characteristic of SiGe based transistors for developing electronics for wide temperature needs of NASA environments such as the Moon, Titan, Mars and Europa. This presentation reports on the status of the development of wide temperature SiGe based electronics for the landers and lunar surface mobility systems.

Understanding Arctic surface temperature differences in reanalyses

NASA Astrophysics Data System (ADS)

Cullather, R. I.; Zhao, B.; Shuman, C. A.; Nowicki, S.

2017-12-01

Reanalyses in the Arctic are widely used for model evaluation and for understanding contemporary climate change. Nevertheless, differences among reanalyses in fundamental meteorological variables including surface air temperature are large. For example, the 1980-2009 mean surface air temperature for the north polar cap (70°N-90°N) among global reanalyses span a range of 2.4 K, which approximates the average warming trend from these reanalyses over the 30-year period of 2.1 K. Understanding these differences requires evaluation over the three principal surface domains of the Arctic: glaciated land, the unglaciated terrestrial surface, and sea ice/ocean. An examination is conducted of contemporary global reanalyses of the ECMWF Interim project, NASA MERRA, MERRA-2, JRA-55, and NOAA CFSR using available in situ data and assessments of the surface energy budget. Overly-simplistic representations of the Greenland Ice Sheet surface are found to be associated with local warm air temperature biases in winter. A review of progress made in the development of the MERRA-2 land-ice representation is presented. Large uncertainty is also found in temperatures over the Arctic tundra and boreal forest zone. But a key focus of temperature differences for northern high latitudes is the Arctic Ocean. Near-surface air temperature differences over the Arctic Ocean are found to be related to discrepancies in sea ice and sea surface temperature boundary data, which are severely compromised in current reanalyses. Issues with the modeled representation of sea ice cover are an additional factor in reanalysis temperature trends. Differences in the representation of the surface energy budget among the various reanalyses are also reviewed.

Understanding Arctic Surface Temperature Differences in Reanalyses

NASA Technical Reports Server (NTRS)

Cullather, Richard; Zhao, Bin; Shuman, Christopher; Nowicki, Sophie

2017-01-01

Reanalyses in the Arctic are widely used for model evaluation and for understanding contemporary climate change. Nevertheless, differences among reanalyses in fundamental meteorological variables including surface air temperature are large. For example, the 1980-2009 mean surface air temperature for the north polar cap (70ÂdegN-90ÂdegN) among global reanalyses span a range of 2.4 K, which approximates the average warming trend from these reanalyses over the 30-year period of 2.1 K. Understanding these differences requires evaluation over the three principal surface domains of the Arctic: glaciated land, the unglaciated terrestrial surface, and sea ice/ocean. An examination is conducted of contemporary global reanalyses of the ECMWF Interim project, NASA MERRA, MERRA-2, JRA-55, and NOAA CFSR using available in situ data and assessments of the surface energy budget. Overly-simplistic representations of the Greenland Ice Sheet surface are found to be associated with local warm air temperature biases in winter. A review of progress made in the development of the MERRA-2 land-ice representation is presented. Large uncertainty is also found in temperatures over the Arctic tundra and boreal forest zone. But a key focus of temperature differences for northern high latitudes is the Arctic Ocean. Near-surface air temperature differences over the Arctic Ocean are found to be related to discrepancies in sea ice and sea surface temperature boundary data, which are severely compromised in current reanalyses. Issues with the modeled representation of sea ice cover are an additional factor in reanalysis temperature trends. Differences in the representation of the surface energy budget among the various reanalyses are also reviewed.

City ventilation of Hong Kong at no-wind conditions

NASA Astrophysics Data System (ADS)

Yang, Lina; Li, Yuguo

We hypothesize that city ventilation due to both thermally-driven mountain slope flows and building surface flows is important in removing ambient airborne pollutants in the high-rise dense city Hong Kong at no-wind conditions. Both spatial and temporal urban surface temperature profiles are an important boundary condition for studying city ventilation by thermal buoyancy. Field measurements were carried out to investigate the diurnal thermal behavior of urban surfaces (mountain slopes, and building exterior walls and roofs) in Hong Kong by using the infrared thermography. The maximum urban surface temperature was measured in the early noon hours (14:00-15:00 h) and the minimum temperature was observed just before sunrise (5:00 h). The vertical surface temperature of the building exterior wall was found to increase with height at daytime and the opposite occurred at nighttime. The solar radiation and the physical properties of the various urban surfaces were found to be important factors affecting the surface thermal behaviors. The temperature difference between the measured maximum and minimum surface temperatures of the four selected exterior walls can be at the highest of 16.7 °C in the early afternoon hours (15:00 h). Based on the measured surface temperatures, the ventilation rate due to thermal buoyancy-induced wall surface flows of buildings and mountain slope winds were estimated through an integral analysis of the natural convection flow over a flat surface. At no-wind conditions, the total air change rate by the building wall flows (2-4 ACH) was found to be 2-4 times greater than that by the slope flows due to mountain surface (1 ACH) due to larger building exterior surface areas and temperature differences with surrounding air. The results provide useful insights into the ventilation of a high-rise dense city at no-wind conditions.

30 CFR 18.23 - Limitation of external surface temperatures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of the...

30 CFR 18.23 - Limitation of external surface temperatures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of the...

30 CFR 18.23 - Limitation of external surface temperatures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of the...

30 CFR 18.23 - Limitation of external surface temperatures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of the...

Characterizing the Diurnal Cycle of Land Surface Temperature and Evapotranspiration at High Spatial Resolution Using Thermal Observations from sUAS.

NASA Astrophysics Data System (ADS)

Dutta, D.; Drewry, D.; Johnson, W. R.

2017-12-01

The surface temperature of plant canopies is an important indicator of the stomatal regulation of plant water use and the associated water flux from plants to atmosphere (evapotranspiration (ET)). Remotely sensed thermal observations using compact, low-cost, lightweight sensors from small unmanned aerial systems (sUAS) have the potential to provide surface temperature (ST) and ET estimates at unprecedented spatial and temporal resolutions, allowing us to characterize the intra-field diurnal variations in canopy ST and ET for a variety of vegetation systems. However, major challenges exist for obtaining accurate surface temperature estimates from low-cost uncooled microbolometer-type sensors. Here we describe the development of calibration methods using thermal chamber experiments, taking into account the ambient optics and sensor temperatures, and applying simple models of spatial non-uniformity correction to the sensor focal-plane-array. We present a framework that can be used to derive accurate surface temperatures using radiometric observations from low-cost sensors, and demonstrate this framework using a sUAS-mounted sensor across a diverse set of calibration and vegetation targets. Further, we demonstrate the use of the Surface Temperature Initiated Closure (STIC) model for computing spatially explicit, high spatial resolution ET estimates across several well-monitored agricultural systems, as driven by sUAS acquired surface temperatures. STIC provides a physically-based surface energy balance framework for the simultaneous retrieval of the surface and atmospheric vapor conductances and surface energy fluxes, by physically integrating radiometric surface temperature information into the Penman-Monteith equation. Results of our analysis over agricultural systems in Ames, IA and Davis, CA demonstrate the power of this approach for quantifying the intra-field spatial variability in the diurnal cycle of plant water use at sub-meter resolutions.

Temperature sensitive surfaces and methods of making same

DOEpatents

Liang, Liang [Richland, WA; Rieke, Peter C [Pasco, WA; Alford, Kentin L [Pasco, WA

2002-09-10

Poly-n-isopropylacrylamide surface coatings demonstrate the useful property of being able to switch charateristics depending upon temperature. More specifically, these coatings switch from being hydrophilic at low temperature to hydrophobic at high temperature. Research has been conducted for many years to better characterize and control the properties of temperature sensitive coatings. The present invention provides novel temperature sensitive coatings on articles and novel methods of making temperature sensitive coatings that are disposed on the surfaces of various articles. These novel coatings contain the reaction products of n-isopropylacrylamide and are characterized by their properties such as advancing contact angles. Numerous other characteristics such as coating thickness, surface roughness, and hydrophilic-to-hydrophobic transition temperatures are also described. The present invention includes articles having temperature-sensitve coatings with improved properties as well as improved methods for forming temperature sensitive coatings.

Evaluation of alternative formulae for calculation of surface temperature in snowmelt models using frequency analysis of temperature observations

Treesearch

C. H. Luce; D. G. Tarboton

2010-01-01

The snow surface temperature is an important quantity in the snow energy balance, since it modulates the exchange of energy between the surface and the atmosphere as well as the conduction of energy into the snowpack. It is therefore important to correctly model snow surface temperatures in energy balance snowmelt models. This paper focuses on the relationship between...

Corneal surface temperature change as the mode of stimulation of the non-contact corneal aesthesiometer.

PubMed

Murphy, P J; Morgan, P B; Patel, S; Marshall, J

1999-05-01

The non-contact corneal aesthesiometer (NCCA) assesses corneal sensitivity by using a controlled pulse of air, directed at the corneal surface. The purpose of this paper was to investigate whether corneal surface temperature change was a component in the mode of stimulation. Thermocouple experiment: A simple model corneal surface was developed that was composed of a moistened circle of filter paper placed on a thermocouple and mounted on a glass slide. The temperature change produced by different stimulus pressures was measured for five different ambient temperatures. Thermal camera experiment: Using a thermal camera, the corneal surface temperature change was measured in nine young, healthy subjects after exposure to different stimulus air pulses. Pulse duration was set at 0.9 s but was varied in pressure from 0.5 to 3.5 millibars. Thermocouple experiment: An immediate drop in temperature was detected by the thermocouple as soon as the air flow was incident on the filter paper. A greater temperature change was produced by increasing the pressure of the incident air flow. A relationship was found and a calibration curve plotted. Thermal camera experiment: For each subject, a drop in surface temperature was detected at each stimulus pressure. Furthermore, as the stimulus pressure increased, the induced reduction in temperature also increased. A relationship was found and a calibration curve plotted. The NCCA air-pulse stimulus was capable of producing a localized temperature change on the corneal surface. The principal mode of corneal nerve stimulation, by the NCCA air pulse, was the rate of temperature change of the corneal surface.

Improving representation of canopy temperatures for modeling subcanopy incoming longwave radiation to the snow surface

NASA Astrophysics Data System (ADS)

Webster, Clare; Rutter, Nick; Jonas, Tobias

2017-09-01

A comprehensive analysis of canopy surface temperatures was conducted around a small and large gap at a forested alpine site in the Swiss Alps during the 2015 and 2016 snowmelt seasons (March-April). Canopy surface temperatures within the small gap were within 2-3°C of measured reference air temperature. Vertical and horizontal variations in canopy surface temperatures were greatest around the large gap, varying up to 18°C above measured reference air temperature during clear-sky days. Nighttime canopy surface temperatures around the study site were up to 3°C cooler than reference air temperature. These measurements were used to develop a simple parameterization for correcting reference air temperature for elevated canopy surface temperatures during (1) nighttime conditions (subcanopy shortwave radiation is 0 W m-2) and (2) periods of increased subcanopy shortwave radiation >400 W m-2 representing penetration of shortwave radiation through the canopy. Subcanopy shortwave and longwave radiation collected at a single point in the subcanopy over a 24 h clear-sky period was used to calculate a nighttime bulk offset of 3°C for scenario 1 and develop a multiple linear regression model for scenario 2 using reference air temperature and subcanopy shortwave radiation to predict canopy surface temperature with a root-mean-square error (RMSE) of 0.7°C. Outside of these two scenarios, reference air temperature was used to predict subcanopy incoming longwave radiation. Modeling at 20 radiometer locations throughout two snowmelt seasons using these parameterizations reduced the mean bias and RMSE to below 10 W m s-2 at all locations.

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs

PubMed Central

Edmondson, J. L.; Stott, I.; Davies, Z. G.; Gaston, K. J.; Leake, J. R.

2016-01-01

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health. PMID:27641002

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs.

PubMed

Edmondson, J L; Stott, I; Davies, Z G; Gaston, K J; Leake, J R

2016-09-19

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs

NASA Astrophysics Data System (ADS)

Edmondson, J. L.; Stott, I.; Davies, Z. G.; Gaston, K. J.; Leake, J. R.

2016-09-01

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

The effects of green areas on air surface temperature of the Kuala Lumpur city using WRF-ARW modelling and Remote Sensing technique

NASA Astrophysics Data System (ADS)

Isa, N. A.; Mohd, W. M. N. Wan; Salleh, S. A.; Ooi, M. C. G.

2018-02-01

Matured trees contain high concentration of chlorophyll that encourages the process of photosynthesis. This process produces oxygen as a by-product and releases it into the atmosphere and helps in lowering the ambient temperature. This study attempts to analyse the effect of green area on air surface temperature of the Kuala Lumpur city. The air surface temperatures of two different dates which are, in March 2006 and March 2016 were simulated using the Weather Research and Forecasting (WRF) model. The green area in the city was extracted using the Normalized Difference Vegetation Index (NDVI) from two Landsat satellite images. The relationship between the air surface temperature and the green area were analysed using linear regression models. From the study, it was found that, the green area was significantly affecting the distribution of air temperature within the city. A strong negative correlation was identified through this study which indicated that higher NDVI values tend to have lower air surface temperature distribution within the focus study area. It was also found that, different urban setting in mixed built-up and vegetated areas resulted in different distributions of air surface temperature. Future studies should focus on analysing the air surface temperature within the area of mixed built-up and vegetated area.

Satellite-derived, melt-season surface temperature of the Greenland Ice Sheet (2000-2005) and its relationship to mass balance

USGS Publications Warehouse

Hall, D.K.; Williams, R.S.; Casey, K.A.; DiGirolamo, N.E.; Wan, Z.

2006-01-01

Mean, clear-sky surface temperature of the Greenland Ice Sheet was measured for each melt season from 2000 to 2005 using Moderate-Resolution Imaging Spectroradiometer (MODIS)–derived land-surface temperature (LST) data-product maps. During the period of most-active melt, the mean, clear-sky surface temperature of the ice sheet was highest in 2002 (−8.29 ± 5.29°C) and 2005 (−8.29 ± 5.43°C), compared to a 6-year mean of −9.04 ± 5.59°C, in agreement with recent work by other investigators showing unusually extensive melt in 2002 and 2005. Surface-temperature variability shows a correspondence with the dry-snow facies of the ice sheet; a reduction in area of the dry-snow facies would indicate a more-negative mass balance. Surface-temperature variability generally increased during the study period and is most pronounced in the 2005 melt season; this is consistent with surface instability caused by air-temperature fluctuations.

Global Surface Temperature Change and Uncertainties Since 1861

NASA Technical Reports Server (NTRS)

Shen, Samuel S. P.; Lau, William K. M. (Technical Monitor)

2002-01-01

The objective of this talk is to analyze the warming trend and its uncertainties of the global and hemi-spheric surface temperatures. By the method of statistical optimal averaging scheme, the land surface air temperature and sea surface temperature observational data are used to compute the spatial average annual mean surface air temperature. The optimal averaging method is derived from the minimization of the mean square error between the true and estimated averages and uses the empirical orthogonal functions. The method can accurately estimate the errors of the spatial average due to observational gaps and random measurement errors. In addition, quantified are three independent uncertainty factors: urbanization, change of the in situ observational practices and sea surface temperature data corrections. Based on these uncertainties, the best linear fit to annual global surface temperature gives an increase of 0.61 +/- 0.16 C between 1861 and 2000. This lecture will also touch the topics on the impact of global change on nature and environment. as well as the latest assessment methods for the attributions of global change.

Validation of AIRS V6 Surface Temperature over Greenland with GCN and NOAA Stations

NASA Technical Reports Server (NTRS)

Lee, Jae N.; Hearty, Thomas; Cullather, Richard; Nowicki, Sophie; Susskind, Joel

2016-01-01

This work compares the temporal and spatial characteristics of the AIRSAMSU (Atmospheric Infrared Sounder Advanced Microwave Sounding Unit A) Version 6 and MODIS (Moderate resolution Imaging Spectroradiometer) Collection 5 derived surface temperatures over Greenland. To estimate uncertainties in space-based surface temperature measurements, we re-projected the MODIS Ice Surface Temperature (IST) to 0.5 by 0.5 degree spatial resolution. We also re-gridded AIRS Skin Temperature (Ts) into the same grid but classified with different cloud conditions and surface types. These co-located data sets make intercomparison between the two instruments relatively straightforward. Using this approach, the spatial comparison between the monthly mean AIRS Ts and MODIS IST is in good agreement with RMS 2K for May 2012. This approach also allows the detection of any long-term calibration drift and the careful examination of calibration consistency in the MODIS and AIRS temperature data record. The temporal correlations between temperature data are also compared with those from in-situ measurements from GC-Net (GCN) and NOAA stations. The coherent time series of surface temperature evident in the correlation between AIRS Ts and GCN temperatures suggest that at monthly time scales both observations capture the same climate signal over Greenland. It is also suggested that AIRS surface air temperature (Ta) can be used to estimate the boundary layer inversion.

Anti-icing properties of superhydrophobic ZnO/PDMS composite coating

NASA Astrophysics Data System (ADS)

Yang, Chao; Wang, Fajun; Li, Wen; Ou, Junfei; Li, Changquan; Amirfazli, Alidad

2016-01-01

We present the excellent anti-icing performance for a superhydrophobic coating surface based on ZnO/polydimethylsiloxane (ZnO/PDMS) composite. The superhydrophobic ZnO/PDMS coating surface was prepared by a facile solution mixing, drop coating, room-temperature curing and surface abrading procedure. The superhydrophobic ZnO/PDMS composite coating possesses a water contact angle of 159.5° and a water sliding angle of 8.3° at room temperature (5 °C). The anti-icing properties of the superhydrophobic coating were investigated by continuously dropping cold-water droplets (about 0 °C) onto the pre-cooled surface using a home-made apparatus. The sample was placed at different tilting angle (0° and 10°) and pre-cooled to various temperatures (-5, -10 and -15 °C) prior to measure. The pure Al surface was also studied for comparison. It was found that icing accretion on the surface could be reduced apparently because the water droplets merged together and slid away from the superhydrophobic surface at all of the measuring temperatures when the surface is horizontally placed. In addition, water droplet slid away completely from the superhydrophobic surface at -5 and -10 °C when the surface is tilted at 10°, which demonstrates its excellent anti-icing properties at these temperatures. When the temperature decreased to -15 °C, though ice accretion on the tilted superhydrophobic coating surface could not be avoided absolutely, the amount of ice formed on the surface is very small, which indicated that the coating surface with superhydrophobicity could significantly reduce ice accumulation on the surface at very low temperature (-15 °C). Importantly, the sample is also stable against repeated icing/deicing cycles. More meaningfully, once the superhydrophobic surface is damaged, it can be repaired easily and rapidly.

Probabilistic Thermal Analysis During Mars Reconnaissance Orbiter Aerobraking

NASA Technical Reports Server (NTRS)

Dec, John A.

2007-01-01

A method for performing a probabilistic thermal analysis during aerobraking has been developed. The analysis is performed on the Mars Reconnaissance Orbiter solar array during aerobraking. The methodology makes use of a response surface model derived from a more complex finite element thermal model of the solar array. The response surface is a quadratic equation which calculates the peak temperature for a given orbit drag pass at a specific location on the solar panel. Five different response surface equations are used, one of which predicts the overall maximum solar panel temperature, and the remaining four predict the temperatures of the solar panel thermal sensors. The variables used to define the response surface can be characterized as either environmental, material property, or modeling variables. Response surface variables are statistically varied in a Monte Carlo simulation. The Monte Carlo simulation produces mean temperatures and 3 sigma bounds as well as the probability of exceeding the designated flight allowable temperature for a given orbit. Response surface temperature predictions are compared with the Mars Reconnaissance Orbiter flight temperature data.

Chemical states of surface oxygen during CO oxidation on Pt(1 1 0) surface revealed by ambient pressure XPS

DOE PAGES

Yu, Youngseok; Koh, Yoobin Esther; Lim, Hojoon; ...

2017-10-20

Here, the study of CO oxidation on Pt(110) surface is revisited using ambient pressure x-ray photoemission spectroscopy. When the surface temperature reaches the activation temperature for CO oxidation under elevated pressure conditions, both the α-phase of PtO 2 oxide and chemisorbed oxygen are formed simultaneously on the surface. Due to the exothermic nature of CO oxidation, the temperature of the Pt surface increases as CO oxidation takes place. As the CO/O 2 ratio increases, the production of CO 2 increases continuously and the surface temperature also increases. Interestingly, within the diffusion limited regions, the amount of surface oxide changes littlemore » while the chemisorbed oxygen is reduced.« less

The effect of water temperature and synoptic winds on the development of surface flows over narrow, elongated water bodies

NASA Technical Reports Server (NTRS)

Segal, M.; Pielke, R. A.

1985-01-01

Simulations of the thermally induced breeze involved with a relatively narrow, elongated water body is presented in conjunction with evaluations of sensible heat fluxes in a stable marine atmospheric surface layer. The effect of the water surface temperature and of the large-scale synoptic winds on the development of surface flows over the water is examined. As implied by the sensible heat flux patterns, the simulation results reveal the following trends: (1) when the synoptic flow is absent or light, the induced surface breeze is not affected noticeably by a reduction of the water surface temperature; and (2) for stronger synoptic flow, the resultant surface flow may be significantly affected by the water surface temperature.

Chemical states of surface oxygen during CO oxidation on Pt(1 1 0) surface revealed by ambient pressure XPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Youngseok; Koh, Yoobin Esther; Lim, Hojoon

Here, the study of CO oxidation on Pt(110) surface is revisited using ambient pressure x-ray photoemission spectroscopy. When the surface temperature reaches the activation temperature for CO oxidation under elevated pressure conditions, both the α-phase of PtO 2 oxide and chemisorbed oxygen are formed simultaneously on the surface. Due to the exothermic nature of CO oxidation, the temperature of the Pt surface increases as CO oxidation takes place. As the CO/O 2 ratio increases, the production of CO 2 increases continuously and the surface temperature also increases. Interestingly, within the diffusion limited regions, the amount of surface oxide changes littlemore » while the chemisorbed oxygen is reduced.« less

Greenhouse effects on Venus

NASA Astrophysics Data System (ADS)

Bell, Peter M.

Calculations that used Pioneer-Venus measurements of atmosphere composition, temperature profiles, and radiative heating predicted Venus' surface temperature ‘very precisely,’ says the Ames Research Center. The calculations predict not only Venus' surface temperature but agree with temperatures measured at various altitudes above the surface by the four Pioneer Venus atmosphere probe craft.Using Pioneer-Venus spacecraft data, a research team has virtually proved that the searing 482° C surface temperature of Venus is due to an atmospheric greenhouse effect. Until now the Venus greenhouse effect has been largely a theory.

Forcing and Responses of the Surface Energy Budget at Summit, Greenland

NASA Astrophysics Data System (ADS)

Miller, Nathaniel B.

Energy exchange at the Greenland Ice Sheet surface governs surface temperature variability, a factor critical for representing increasing surface melt extent, which portends a rise in global sea level. A comprehensive set of cloud, tropospheric, near-surface and sub-surface measurements at Summit Station is utilized to determine the driving forces and subsequent responses of the surface energy budget (SEB). This budget includes radiative, turbulent, and ground heat fluxes, and ultimately controls the evolution of surface temperature. At Summit Station, clouds radiatively warm the surface in all months with an annual average cloud radiative forcing value of 33 W m -2, largely driven by the occurrence of liquid-bearing clouds. The magnitude of the surface temperature response is dependent on how turbulent and ground heat fluxes modulate changes to radiative forcing. Relationships between forcing terms and responding surface fluxes show that changes in the upwelling longwave radiation compensate for 65-85% (50- 60%) of the total change in radiative forcing in the winter (summer). The ground heat flux is the second largest response term (16% annually), especially during winter. Throughout the annual cycle, the sensible heat flux response is comparatively constant (9%) and latent heat flux response is only 1.5%, becoming more of a factor in modulating surface temperature responses during the summer. Combining annual cycles of these responses with cloud radiative forcing results, clouds warm the surface by an estimated 7.8°C annually. A reanalysis product (ERA-I), operational model (CFSv2), and climate model (CESM) are evaluated utilizing the comprehensive set of SEB observations and process-based relationships. Annually, surface temperatures in each model are warmer than observed with overall poor representation of the coldest surface temperatures. Process-based relationships between different SEB flux terms offer insight into how well a modeling framework represents physical processes and the ability to distinguish errors in forcing versus those in physical representation. Such relationships convey that all three models underestimate the response of surface temperatures to changes in radiative forcing. These results provide a method to expose model deficiencies and indicate the importance of representing surface, sub-surface and boundary-layer processes when portraying cloud impacts on surface temperature variability.

Who’s on top? SST proxy comparison from the Peru Margin Upwelling System

NASA Astrophysics Data System (ADS)

Chazen, C.; Herbert, T.; Altabet, M. A.

2009-12-01

The Peru Margin upwelling region is situated at the interface between the poleward Peru Undercurrent and the equatorward Peru Coastal current. Strong coastal winds force cold, nutrient-rich thermocline waters to the surface. Sea surface temperatures in this region fluctuate sub-annually with changes in the position of the Intertropical convergence zone (ITCZ) and sub-decadally with modifications in the strength of Walker Circulation. In contrast, the temperature of the Peru Margin thermocline is stable, isolated from surface winds and slow to respond to major perturbations in surface temperature. Using high resolution sampling (6-7 year) across an annually laminated sediment core from the heart of the Peru Margin upwelling system (15°S) we explore how Uk’37 temperatures compare with TEX86 temperatures across a 200-year interval in the Mid-late Holocene. Mean late Holocene Uk’37 temperatures, extracted from a high sedimentation rate core from the Peru Margin are similar to modern mean annual sea surface temperatures at 15°S. Multi-decadal-scale (50-100 year) Uk’37 temperature fluctuations oscillate about the mean by 1.5°C. These rapid temperature changes are coherent with fluctuations in surface productivity (C37total and Biogenic Silica) in addition to sub-surface denitrification (δ15N). In contrast, TEX86 temperatures derived from identical samples exhibit colder temperatures than modern mean annual conditions and virtually no temperature fluctuation. We posit that TEX86 values are recording temperatures below the photic zone near the mix-layer-thermocline boundary and may, on longer timescales provide invaluable information about thermocline temperature. With this interpretation in mind, we present a TEX86-based long-term thermocline reconstruction over the Holocene.

A novel resource sharing algorithm based on distributed construction for radiant enclosure problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Finzell, Peter; Bryden, Kenneth M.

This study demonstrates a novel approach to solving inverse radiant enclosure problems based on distributed construction. Specifically, the problem of determining the temperature distribution needed on the heater surfaces to achieve a desired design surface temperature profile is recast as a distributed construction problem in which a shared resource, temperature, is distributed by computational agents moving blocks. The sharing of blocks between agents enables them to achieve their desired local state, which in turn achieves the desired global state. Each agent uses the current state of their local environment and a simple set of rules to determine when to exchangemore » blocks, each block representing a discrete unit of temperature change. This algorithm is demonstrated using the established two-dimensional inverse radiation enclosure problem. The temperature profile on the heater surfaces is adjusted to achieve a desired temperature profile on the design surfaces. The resource sharing algorithm was able to determine the needed temperatures on the heater surfaces to obtain the desired temperature distribution on the design surfaces in the nine cases examined.« less

A novel resource sharing algorithm based on distributed construction for radiant enclosure problems

DOE PAGES

Finzell, Peter; Bryden, Kenneth M.

2017-03-06

This study demonstrates a novel approach to solving inverse radiant enclosure problems based on distributed construction. Specifically, the problem of determining the temperature distribution needed on the heater surfaces to achieve a desired design surface temperature profile is recast as a distributed construction problem in which a shared resource, temperature, is distributed by computational agents moving blocks. The sharing of blocks between agents enables them to achieve their desired local state, which in turn achieves the desired global state. Each agent uses the current state of their local environment and a simple set of rules to determine when to exchangemore » blocks, each block representing a discrete unit of temperature change. This algorithm is demonstrated using the established two-dimensional inverse radiation enclosure problem. The temperature profile on the heater surfaces is adjusted to achieve a desired temperature profile on the design surfaces. The resource sharing algorithm was able to determine the needed temperatures on the heater surfaces to obtain the desired temperature distribution on the design surfaces in the nine cases examined.« less

Calculation of thermal inertia from day-night measurements separated by days or weeks

NASA Technical Reports Server (NTRS)

Kahle, A. B.; Alley, R. E.

1985-01-01

The calculation of the thermal inertia of an area from remotely sensed data involves the measurement of the surface albedo and the determination of the diurnal temperature range of the surface in image format. The temperature-range image is calculated from surface thermal radiance measured as near as possible to the time of maximum surface temperature and (predawn) surface minimum temperature. Ordinarily, both surface-temperature images are measured within the same 12-hour period. If this is impossible, then the measurement of the predawn surface radiance within a 36-hour period has been considered to be adequate, although less satisfactory. The problems arising in connection with the impossibility to conduct measurements within the same 12-hour period are studied, and suggestions are made for cases in which only relative thermal inertia across an area is required. In such cases investigators should consider using the best day-night temperature pairs available, even if not acquired within a 12 to 36 hour period.

Effect of design factors on surface temperature and wear in disk brakes

NASA Technical Reports Server (NTRS)

Santini, J. J.; Kennedy, F. E.; Ling, F. F.

1976-01-01

The temperatures, friction, wear and contact conditions that occur in high energy disk brakes are studied. Surface and near surface temperatures were monitored at various locations in a caliper disk brake during drag type testing, with friction coefficient and wear rates also being determined. The recorded transient temperature distributions in the friction pads and infrared photographs of the rotor disk surface both showed that contact at the friction surface was not uniform, with contact areas constantly shifting due to nonuniform thermal expansion and wear. The effect of external cooling and of design modifications on friction, wear and temperatures was also investigated. It was found that significant decreases in surface temperature and in wear rate can be achieved without a reduction in friction either by slotting the contacting face of the brake pad or by modifying the design of the pad support to improve pad compliance. Both design changes result in more uniform contact conditions on the friction surface.