[Considerations when using creatinine as a measure of kidney function].

PubMed

Drion, I Iefke; Fokkert, M J Marion; Bilo, H J G Henk

2013-01-01

Reported serum creatinine concentrations can sometimes vary considerably, even when the renal function does less so or even not. This variation is partly due to true changes in actual serum concentration, and partly due to interferences in the measurement technique, thus not reflecting a true change in concentration. Increased or decreased endogenous creatinine production, ingested creatinine sources through meat eating or certain creatine formulations, and interference by either browning of chromogenic substances in Jaffe measurement techniques or promotors and inhibitors of enzymatic reaction methods do play a role. Reliable serum creatinine measurements are needed for renal function estimating equations. In screening circumstances and daily practice, chronic kidney disease staging is based on these estimated glomerular filtration rate values. Given the possible influences on reported serum creatinine concentrations, it is important for health care workers to remain critical when interpreting outcomes of renal function estimating equations and to not see every reported result based on an equation as a true reflection of renal function.

A Multivariate Analysis of Metal Concentrations in Two Fish Species of the Nyl River System, Limpopo Province, South Africa.

PubMed

Musa, R; Gerber, R; Greenfield, R

2017-06-01

Increased toxicity due to high metal concentrations may hinder the ecological integrity of aquatic ecosystems in sustaining life. The non-biodegradable nature of metals may result in bioaccumulation in aquatic organisms. Due to ecological and social aspects it is imperative for monitoring schemes to identify possible impacts to the systems integrity. This paper discusses accumulation patterns of seven metals (Al, Cr, Cu, Fe, Mn, Sr and Zn) in tissues of two fish species, namely Clarias gariepinus and Oreochromis mossambicus at two selected sites, the first located upstream of Modimolle (NRS1), and the second located downstream of the town (NRS2). Gills, liver, muscle and skin tissues were analysed for metal concentrations using standard microwave digestion and inductively coupled plasma mass spectrometry techniques. Statistical results indicated higher concentrations of metals at NRS2 in comparison to NRS1, indicating that Modimolle plays a potential role in introducing metals into the aquatic system.

Effects of Whole-Ecosystem Warming on Porewater Chemistry and Hydrology in a Northern Peatland

NASA Astrophysics Data System (ADS)

Griffiths, N.; Sebestyen, S. D.

2016-12-01

Northern peatlands are carbon-rich ecosystems, and thus it is important to understand the effects of climate change on carbon cycle feedbacks in these vulnerable systems. An ecosystem-scale experiment is evaluating the effects of warming and elevated CO2 on an ombrotrophic bog in northern Minnesota, USA. Ten enclosures, each 12-m in diameter, were constructed in the peatland to allow for both above and belowground warming. Each enclosure receives one of five temperature treatments (+0 to +9°C), with half of the enclosures receiving elevated CO2 (+500ppm) and the other half ambient CO2. A belowground corral with a lateral drainage system surrounds each enclosure, and allows for measurements of lateral outflow volume and chemistry. Piezometers are used to sample porewater chemistry at different depths (0-3m) into the peat. We evaluated the effects of one year of whole-ecosystem warming on depth-specific porewater chemistry and outflow dynamics. Changes in porewater chemistry were observed upon initiation of whole-ecosystem warming. Total organic carbon (TOC) concentrations increased in near-surface porewater in the warmer enclosures, while concentrations were lower and similar to pre-treatment conditions in the ambient (+0°C) enclosures. The changes in TOC concentration measured in response to whole-ecosystem warming were initially limited to only the near-surface porewater (0 m); however, TOC concentrations began to increase at 0.3 m depth after several months of warming. These changes in TOC concentrations were also reflected in water draining from each enclosure, with generally higher TOC concentrations in water flowing from warmer enclosures. However, warmer treatments tended to have lower water outflow rates, possibly due to increased evapotranspiration, and thus TOC fluxes were generally lowest from the warmest enclosures. Overall, these initial results suggest that warming may increase porewater TOC concentrations, possibly due to increased mineralization rates of peat; however, due to the interaction with hydrology, export of this TOC to downstream ecosystems may be lower with warming. Continued measurements over the next 10 years will evaluate the long-term effects of warming on peatland chemistry and hydrology.

Antibacterial potential assessment of jasmine essential oil against e. Coli.

PubMed

Rath, C C; Devi, S; Dash, S K; Mishra, R K

2008-01-01

The antibacterial activity of Jasmine (Jasminum sambac L.) flower hydro steam distilled essential oil, synthetic blends and six major individual components was assessed against Escherichia coli (MTCC-443) strain. The activity was bactericidal. Minimum inhibitory concentration was determined by tube dilution technique, and the Minimum inhibitory concentration ranged between 1.9-31.25 mul/ml. Phenolcoefficient of the oil, synthetic blends and components varied between 0.6-1.7. The activity of the chemicals was possibly due to the inhibition of cell membrane synthesis.

Research of CO2 concentration in naturally ventilated lecture room

NASA Astrophysics Data System (ADS)

Laska, Marta; Dudkiewicz, Edyta

2017-11-01

Naturally ventilated buildings especially dedicated for educational purposes need to be design to achieve required level of thermal comfort and indoor air quality. It is crucial in terms of both: health and productivity of the room users. Higher requirements of indoor environment are important due to the level of students concentration, their ability to acquire new knowledge and willingness to interact with the lecturer. The article presents the results of experimental study and surveys undertaken in naturally ventilated lecture room. The data is analysed in terms of CO2 concentration and its possible influence on users. Furthermore the outcome of the research is compared with the CO2 concentration models available in the literature.

Magnetic nanoparticle hyperthermia cancer treatment efficacy dependence on cellular and tissue level particle concentration and particle heating properties

NASA Astrophysics Data System (ADS)

Petryk, Alicia A.; Misra, Adwiteeya; Mazur, Courtney M.; Petryk, James D.; Hoopes, P. J.

2015-03-01

The use of nanotechnology for the treatment of cancer affords the possibility of highly specific tumor targeting and improved treatment efficacy. Iron oxide magnetic nanoparticles (IONPs) have demonstrated success as an ablative mono-therapy and targetable adjuvant therapy. However, the relative therapeutic value of intracellular vs. extracellular IONPs remains unclear. Our research demonstrates that both extracellular and intracellular IONPs generate cytotoxicity when excited by an alternating magnetic field (AMF). While killing individual cells via intracellular IONP heating is an attractive goal, theoretical models and experimental results suggest that this may not be possible due to limitations of cell volume, applied AMF, IONP concentration and specific absorption rate (SAR). The goal of this study was to examine the importance of tumor size (cell number) with respect to IONP concentration. Mouse mammary adenocarcinoma cells were incubated with IONPs, washed, spun into different pellet sizes (0.1, 0.5 and 2 million cells) and exposed to AMF. The level of heating and associated cytotoxicity depended primarily on the number of IONPs /amount Fe per cell pellet volume and the relative volume of the cell pellet. Specifically, larger cell pellets achieved greater relative cytotoxicity due to greater iron amounts, close association and subsequently higher temperatures.

Temporal trends and spatial patterns in nutrient export along the Mississippi River and its Tributaries

NASA Astrophysics Data System (ADS)

Stewart, B.; Li, L.

2017-12-01

The Mississippi River, the largest river in the U. S., exports excessive nutrients from the land to the sea, causing the problem of hypoxia in the Gulf of Mexico. In this research, we examined nutrient export along the Mississippi River and its tributaries to understand its trends and patterns and to identify the major factors contributing to these trends. We examined nutrient data from 1950 - 2017 for four sites along the Mississippi River and four tributary sites from the U. S. Geological Survey. The species included: total nitrogen, organic nitrogen, ammonia, nitrate, orthophosphate, and phosphorous. We analyzed the power law relationship of concentration and discharge, for which the export of nutrient species exhibited several trends. Both nitrogen (N) and phosphorous (P) species exhibited mostly chemodynamic behavior. This is in contrast to previous observations in smaller agricultural land where N and P export was mostly chemostatic with no significant change in concentration as discharge varies, suggesting possible scaling effects at different spatial scales. We also compared the average annual concentration over time at each site. The N concentration decreased from upstream to downstream, likely due to greater agricultural activities in the upstream Mississippi river and possible denitrification along the river. The N concentration also increased with time. The P species, however, fluctuated from site to site with no clear spatial patterns, but consistently exhibited higher concentrations at upstream sites with greater agricultural activities. The P species also fluctuated over time, likely due to patterns in discharge and agricultural activities. The results of this research can be further explored by calculating the total export of nutrients into the Gulf of Mexico to determine limits and drivers of nutrient export for better water management, thus helping prevent hypoxia and eutrophication within the Mississippi River basin.

Effect of sediment composition on methane concentration and production in the transition zone of a mangrove (Sepetiba Bay, Rio de Janeiro, Brazil).

PubMed

Marinho, C C; Campos, E A; Guimarães, J R D; Esteves, F A

2012-08-01

The aim of this research was to evaluate the effect of sediment composition on methane (CH4) dynamics in sediments of different areas in the transition zone between a mangrove and the sea. This research was conducted in a mangrove at Coroa Grande, on the southern coast of Rio de Janeiro. Samples were collected at three stations: (1) region colonised by Rhizophora mangle L. on the edge of the mangrove, (2) region colonised by seagrasses and (3) infra-littoral region without vegetation. Samples were collected from the surface layer of the sediment to determine the concentrations of nutrients (C, N and P) and CH4 concentration and production. We observed that concentrations of CH4 and carbon (C) were significantly higher (p < 0.05) in station 1 than station 3. The molar ratios (C:N, C:P and N:P) suggest that the origin of the substrate is mainly autochthonous. Methanogenesis was initially low, possibly due to competition between methanogens and sulfate reducers, and increased significantly (p < 0.05) on the twenty-sixth day in the sediment of station 1, probably due to higher organic matter (OM) availability in this region. Results indicate that methanogenic activity observed herein is not regulated by the amount or quality of OM, but by other factors. The concentration of CH4 in the sea-land ecotone at Mangrove Coroa Grande is a function of available OM suggesting a possible inhibition of methanotrophy by intense oxygen consumption in the soil surface covered by detritus of Rhizophora mangle vegetation.

Sexual recombination and the possibility of cryptic heterokaryosis in Aspergillus flavus

USDA-ARS?s Scientific Manuscript database

Aspergillus flavus infects both plants and animals and is of toxicological importance due to its production of aflatoxins (AFs). Recent efforts to reduce AF concentrations have focused on the use of the biocontrols AF36 and Afla-Guard®, both of which contain nonaflatoxigenic A. flavus strains as an ...

The chemistry of the S-nitrosoglutathione/glutathione system

PubMed Central

Singh, S. P.; Wishnok, J. S.; Keshive, M.; Deen, W. M.; Tannenbaum, S. R.

1996-01-01

S-Nitrosothiols have generated considerable interest due to their ability to act as nitric oxide (NO) donors and due to their possible involvement in bioregulatory systems—e.g., NO transfer reactions. Elucidation of the reaction pathways involved in the modification of the thiol group by S-nitrosothiols is important for understanding the role of S-nitroso compounds in vivo. The modification of glutathione (GSH) in the presence of S-nitrosoglutathione (GSNO) was examined as a model reaction. Incubation of GSNO (1 mM) with GSH at various concentrations (1–10 mM) in phosphate buffer (pH 7.4) yielded oxidized glutathione, nitrite, nitrous oxide, and ammonia as end products. The product yields were dependent on the concentrations of GSH and oxygen. Transient signals corresponding to GSH conjugates, which increased by one mass unit when the reaction was carried out with 15N-labeled GSNO, were identified by electrospray ionization mass spectrometry. When morpholine was present in the reaction system, N-nitrosomorpholine was formed. Increasing concentrations of either phosphate or GSH led to lower yields of N-nitrosomorpholine. The inhibitory effect of phosphate may be due to reaction with the nitrosating agent, nitrous anhydride (N2O3), formed by oxidation of NO. This supports the release of NO during the reaction of GSNO with GSH. The products noted above account quantitatively for virtually all of the GSNO nitrogen consumed during the reaction, and it is now possible to construct a complete set of pathways for the complex transformations arising from GSNO + GSH. PMID:8962068

Effects of abandoned arsenic mine on water resources pollution in north west of iran.

PubMed

Hajalilou, Behzad; Mosaferi, Mohammad; Khaleghi, Fazel; Jadidi, Sakineh; Vosugh, Bahram; Fatehifar, Esmail

2011-01-01

Pollution due to mining activities could have an important role in health and welfare of people who are living in mining area. When mining operation finishes, environ-ment of mining area can be influenced by related pollution e.g. heavy metals emission to wa-ter resources. The present study was aimed to evaluate Valiloo abandoned arsenic mine ef-fects on drinking water resources quality and possible health effects on the residents of min-ing area in the North West of Iran. Water samples and some limited composite wheat samples in downstream of min-ing area were collected. Water samples were analyzed for chemical parameters according to standard methods. For determination of arsenic in water samples, Graphite Furnace Atomic Absorption Spectrometric Method (GFAAS) and for wheat samples X - Ray Fluorescence (XRF) and Inductively Coupled Plasma Method (ICP) were used. Information about possible health effects due to exposure to arsenic was collected through interviews in studied villages and health center of Herris City. The highest concentrations of arsenic were measured near the mine (as high as 2000 µg/L in Valiloo mine opening water). With increasing distance from the mine, concentration was decreased. Arsenic was not detectable in any of wheat samples. Fortunately, no health effects had been reported between residents of studied area due to exposure to arsenic. Valiloo abandoned arsenic mine has caused release of arsenic to the around en-vironment of the mine, so arsenic concentration has been increased in the groundwater and also downstream river that requires proper measures to mitigate spread of arsenic.

Profiling Groundwater Salt Concentrations in Mangrove Swamps and Tropical Salt Flats

NASA Astrophysics Data System (ADS)

Ridd, Peter V.; Sam, Renagi

1996-11-01

The salt concentration of groundwater in mangrove swamps is an important parameter controlling the growth of mangrove species. Extremely high salt concentrations of groundwater in tropical salt flats are responsible for the complete absence of macrophytes. Determining groundwater salt concentrations can be a very time-consuming and laborious process if conventional techniques are used. Typically, groundwater samples must be extracted for later laboratory analysis. In this work, a simple conductivity probe has been developed which may be inserted easily to a depth of 2 m into the sediment. The changes in conductivity of the sediment is due primarily to porewater salt concentration, and thus ground conductivity is useful in determining changes in groundwater salt concentrations. Using the conductivity probe, transects of sediment conductivity can be undertaken quickly. As an example of a possible application of the probe, transects of ground conductivity were taken on a mangrove swamp/saltflat system. The transects show clearly the sharp delineation in conductivity between the salt flat and mangrove swamp due to a change in groundwater salt concentrations. Horizontal and vertical salt concentration gradients of up to 50 g l -1 m -1and 150 g l -1 m -1, respectively, were found. Very sharp changes in groundwater salt concentrations at the interface between salt flats and mangroves indicate that the mangroves may be modifying the salinity of the groundwater actively.

Municipal landfill leachate characteristics and feasibility of retrofitting existing treatment systems with deammonification - A full scale survey.

PubMed

Mohammad-Pajooh, Ehsan; Weichgrebe, Dirk; Cuff, Graham

2017-02-01

Leachate characteristics, applied technologies and energy demand for leachate treatment were investigated through survey in different states of Germany. Based on statistical analysis of leachate quality data from 2010 to 2015, almost half of the contaminants in raw leachate satisfy direct discharge limits. Decrease in leachate pollution index of current landfills is mainly related to reduction in concentrations of certain heavy metals (Pb, Zn, Cd, Hg) and organics (biological oxygen demand (BOD 5 ), chemical oxygen demand (COD), and adsorbable organic halogen (AOX)). However, contaminants of concern remain COD, ammonium-nitrogen (NH 4 N) and BOD 5 with average concentrations in leachate of about 1850, 640, and 120 mg/L respectively. Concentrations of COD and NH 4 N vary seasonally, mainly due to temperature changes; concentrations during the first quarter of the year are mostly below the annual average value. Electrical conductivity (EC) of leachate may be used as a time and cost saving alternative to monitor sudden changes in concentration of these two parameters, due to high correlations of around 0.8 with both COD and NH 4 N values which are possibly due to low heavy metal concentrations in leachate. The decreased concentrations of heavy metals and BOD 5 favor the retrofitting of an existing biological reactor (nitrification/denitrification) with the deammonification process and post denitrification, as this lowers average annual operational cost (in terms of energy and external carbon source) and CO 2 emission by €25,850 and 15,855 kg CO 2,eq respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Estimation of Anthropogenic Uranium Concentration in Japanese Agricultural Soils from Phosphatic Fertilizers

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

Tagami, K.; Uchida, S.; Takeda, H.

2006-07-01

In this study, estimation of excess amount of uranium in Japanese agricultural soils due to phosphatic fertilizer application were carried out, by measuring concentrations of total U and Th in 82 soils collected throughout Japan by inductively coupled plasma mass spectrometry (ICP-MS). Since Japanese non-agricultural fields have an average U/Th ratio of 0.23, thus, using U/Th ratios in non-agricultural areas, we thought that it is possible to calculate amounts of excess U due to the application of fertilizers. It was estimated that about 50% of total U in paddy field soils (range: 4-78%) and about 48% of total U inmore » upland field soils (range: 4-74%) were originated from the phosphatic fertilizers. (authors)« less

Mental Symptoms in Huntington's Disease and a Possible Primary Aminergic Neuron Lesion

NASA Astrophysics Data System (ADS)

Mann, J. John; Stanley, Michael; Gershon, Samuel; Rossor, M.

1980-12-01

Monoamine oxidase activity was higher in the cerebral cortex and basal ganglia of patients dying from Huntington's disease than in controls. Enzyme kinetics and multiple substrate studies indicated that the increased activity was due to elevated concentrations of monoamine oxidase type B. Concentrations of homovanillic acid were increased in the cerebral cortex but not in the basal ganglia of brains of patients with Huntington's disease. These changes may represent a primary aminergic lesion that could underlie some of the mental symptoms of this disease.

Antibacterial Potential Assessment of Jasmine Essential Oil Against E. Coli

PubMed Central

Rath, C. C.; Devi, S.; Dash, S. K.; Mishra, R. K.

2008-01-01

The antibacterial activity of Jasmine (Jasminum sambac L.) flower hydro steam distilled essential oil, synthetic blends and six major individual components was assessed against Escherichia coli (MTCC-443) strain. The activity was bactericidal. Minimum inhibitory concentration was determined by tube dilution technique, and the Minimum inhibitory concentration ranged between 1.9-31.25 μl/ml. Phenolcoefficient of the oil, synthetic blends and components varied between 0.6-1.7. The activity of the chemicals was possibly due to the inhibition of cell membrane synthesis. PMID:20046722

A High-Protein Soybean Cultivar Contains Lower Isoflavones and Saponins but Higher Minerals and Bioactive Peptides than a Low-Protein Cultivar

USDA-ARS?s Scientific Manuscript database

Consumption of soybean products has increased considerably in the last few years, possibly due to the functional properties and the presence of bioactive compounds which bring health benefits to consumers. The process of germination has been shown to increase the concentration of a number of these ...

Finding the "g"-Factor in Brain Structure Using the Method of Correlated Vectors

ERIC Educational Resources Information Center

Colom, Roberto; Jung, Rex E.; Haier, Richard J.

2006-01-01

It is unclear whether brain mechanisms underlying human intelligence are distributed throughout the brain or mainly concentrated in the frontal lobes. Data are inconsistent possibly due, at least in part, to the different ways the construct of intelligence is measured. Here we apply the method of correlated vectors to determine how the general…

40 CFR Appendix C to Part 132 - Great Lakes Water Quality Initiative Methodologies for Development of Human Health Criteria and...

Code of Federal Regulations, 2013 CFR

2013-07-01

... organisms where higher doses or concentrations resulted in an adverse effect. Quantitative structure... probable or possible human carcinogen, when, because of major qualitative or quantitative limitations, the... quantitative risk assessment, but for which data are inadequate for Tier I criterion development due to a tumor...

40 CFR Appendix C to Part 132 - Great Lakes Water Quality Initiative Methodologies for Development of Human Health Criteria and...

Code of Federal Regulations, 2014 CFR

2014-07-01

... organisms where higher doses or concentrations resulted in an adverse effect. Quantitative structure... probable or possible human carcinogen, when, because of major qualitative or quantitative limitations, the... quantitative risk assessment, but for which data are inadequate for Tier I criterion development due to a tumor...

40 CFR Appendix C to Part 132 - Great Lakes Water Quality Initiative Methodologies for Development of Human Health Criteria and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... organisms where higher doses or concentrations resulted in an adverse effect. Quantitative structure... probable or possible human carcinogen, when, because of major qualitative or quantitative limitations, the... quantitative risk assessment, but for which data are inadequate for Tier I criterion development due to a tumor...

Influence of dissolved organic carbon content on modelling natural organic matter acid-base properties.

PubMed

Garnier, Cédric; Mounier, Stéphane; Benaïm, Jean Yves

2004-10-01

Natural organic matter (NOM) behaviour towards proton is an important parameter to understand NOM fate in the environment. Moreover, it is necessary to determine NOM acid-base properties before investigating trace metals complexation by natural organic matter. This work focuses on the possibility to determine these acid-base properties by accurate and simple titrations, even at low organic matter concentrations. So, the experiments were conducted on concentrated and diluted solutions of extracted humic and fulvic acid from Laurentian River, on concentrated and diluted model solutions of well-known simple molecules (acetic and phenolic acids), and on natural samples from the Seine river (France) which are not pre-concentrated. Titration experiments were modelled by a 6 acidic-sites discrete model, except for the model solutions. The modelling software used, called PROSECE (Programme d'Optimisation et de SpEciation Chimique dans l'Environnement), has been developed in our laboratory, is based on the mass balance equilibrium resolution. The results obtained on extracted organic matter and model solutions point out a threshold value for a confident determination of the studied organic matter acid-base properties. They also show an aberrant decreasing carboxylic/phenolic ratio with increasing sample dilution. This shift is neither due to any conformational effect, since it is also observed on model solutions, nor to ionic strength variations which is controlled during all experiments. On the other hand, it could be the result of an electrode troubleshooting occurring at basic pH values, which effect is amplified at low total concentration of acidic sites. So, in our conditions, the limit for a correct modelling of NOM acid-base properties is defined as 0.04 meq of total analysed acidic sites concentration. As for the analysed natural samples, due to their high acidic sites content, it is possible to model their behaviour despite the low organic carbon concentration.

A comparison of the dose from natural radionuclides and artificial radionuclides after the Fukushima nuclear accident

PubMed Central

Hosoda, Masahiro; Tokonami, Shinji; Omori, Yasutaka; Ishikawa, Tetsuo; Iwaoka, Kazuki

2016-01-01

Due to the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the evacuees from Namie Town still cannot reside in the town, and some continue to live in temporary housing units. In this study, the radon activity concentrations were measured at temporary housing facilities, apartments and detached houses in Fukushima Prefecture in order to estimate the annual internal exposure dose of residents. A passive radon–thoron monitor (using a CR-39) and a pulse-type ionization chamber were used to evaluate the radon activity concentration. The average radon activity concentrations at temporary housing units, including a medical clinic, apartments and detached houses, were 5, 7 and 9 Bq m−3, respectively. Assuming the residents lived in these facilities for one year, the average annual effective doses due to indoor radon in each housing type were evaluated as 0.18, 0.22 and 0.29 mSv, respectively. The average effective doses to all residents in Fukushima Prefecture due to natural and artificial sources were estimated using the results of the indoor radon measurements and published data. The average effective dose due to natural sources for the evacuees from Namie Town was estimated to be 1.9 mSv. In comparison, for the first year after the FDNPP accident, the average effective dose for the evacuees due to artificial sources from the accident was 5.0 mSv. Although residents' internal and external exposures due to natural radionuclides cannot be avoided, it might be possible to lower external exposure due to the artificial radionuclides by changing some behaviors of residents. PMID:26838130

Radionuclides at Descartes in the central highlands

NASA Technical Reports Server (NTRS)

Wrigley, R. C.

1973-01-01

Throium, uranium, potassium, aluminium-26, and sodium-22 were measured by nondestructive gamma ray spectrometry in six soil and two rock samples gathered by Apollo 16 in the lunar central highlands. The soil samples probably include both major geologic formations in the vicinity, the Cayley and Descartes Formations, although it is possible that the Descartes Formation is not represented. The rock samples have low concentrations of primordial radionuclides. The Al concentrations were lower than could be expected from the high abundance of alumina in the Apollo 16 soils reported earlier, but this could be due to lower concentrations of target elements in these soils, sampling depth variations, or regolithic mixing (exposure age variations).

Effects of differently composed feeds and physical stress on plasma gastrin concentration in horses.

PubMed

Sandin, A; Girma, K; Sjöholm, B; Lindholm, A; Nilsson, G

1998-01-01

Plasma gastrin concentrations were determined in 6 Standardbreds (4 geldings and 2 mares) after 3 different meals consisting of unlimited amounts of hay (8-9 kg per horse), a restricted amount of hay (0.6 kg/100 kg body-weight) and grain (0.2 kg/100 kg body-weight) in combination or of grain alone (0.2 kg/100 kg body-weight). In another series of experiments the possible role of gastrin as a stress hormone was investigated. Plasma gastrin and cortisol concentrations were determined during fasting and compared with concentrations during hay feeding. In addition, gastrin and cortisol concentrations were determined before, during and after 2 kinds of physical exercise on a treadmill. Meal stimulation significantly increased the plasma gastrin concentration, irrespective of the meal composition. An immediate and large increase in plasma gastrin concentration was found when voluminous meals were given, whereas a small meal evoked a later onset of gastrin release, suggesting that gastric distention plays an important role in inducing gastrin release during a meal. Meals consisting of grain seem to evoke a slower onset and then a more prolonged gastrin response than a hay meal, possibly due to different emptying rates of the stomach. Nervous excitation may play a minor role in the activation of gastrin release in horses. No experimental support was obtained for the idea that gastrin acts as a stress hormone in the horse.

Changes in the chemistry of lakes and precipitation in high-elevation national parks in the western United States, 1985–1999

USGS Publications Warehouse

Clow, David W.; Sickman, James O.; Striegl, Robert G.; Krabbenhoft, David P.; Elliott, John G.; Dornblaser, Mark M.; Roth, David A.; Campbell, Donald H.

2003-01-01

High-elevation lakes in the western United States are sensitive to atmospheric deposition of sulfur and nitrogen due to fast hydrologic flushing rates, short growing seasons, an abundance of exposed bedrock, and a lack of well-developed soils. This sensitivity is reflected in the dilute chemistry of the lakes, which was documented in the U.S. Environmental Protection Agency's Western Lake Survey of 1985. Sixty-nine lakes in seven national parks sampled during the 1985 survey were resampled during fall 1999 to investigate possible decadal-scale changes in lake chemistry. In most lakes, SO4 concentrations were slightly lower in 1999 than in 1985, consistent with a regional decrease in precipitation SO4 concentrations and in SO2 emissions in the western United States. Nitrate concentrations also tended to be slightly lower in 1999 than in 1985, in contrast with generally stable or increasing inorganic N deposition in the west. Differences in alkalinity were variable among parks but were relatively consistent within each park. Possible effects of annual and seasonal-scale variations in precipitation amount on lake chemistry were evaluated based on climate data available for the parks and an analysis of climatic effects at two research watersheds with long-term records. Results suggest that rain prior to sampling in 1985 may have caused elevated NO3 in some lakes due to direct runoff of precipitation and flushing of NO3 from alpine soils, which may explain some of the decrease in NO3 concentrations observed in survey lakes.

Effect of midgap defect states on the optical properties of Ge20Se70Te10 nano colloids

NASA Astrophysics Data System (ADS)

Cheruvalath, Ajina; Sebastian, Indu; Sebastian, Mathew; Nampoori, V. P. N.; Thomas, Sheenu

2017-10-01

In this work, we report the linear and nonlinear optical studies on a pseudo binary chalcogenide glass of composition Ge20 Se70 Te10 in its nano colloidal form. The possibility of tuning the band gap, nonlinear refractive index and nonlinear absorption of the material by changing the glass loading in the colloid has been revealed. A red shift in the band edge along with an intermediate peak in the band tail due to defect states is observed with increasing concentration. Photoluminescence studies confirm the existence of intermediate defect states in the bandgap. Nonlinear properties analyzed with open and closed aperture z scan technique reveal that the nonlinear refraction enhances due to resonant effects as the band gap of the colloid gets near the one photon absorption edge. The nonlinear absorption is prominent in the concentrated sample due to the presence of defect states which acts as an intermediate level in two step photon absorption.

[Measures against Radiation Exposure Due to Large-Scale Nuclear Accident in Distant Place--Radioactive Materials in Nagasaki from Fukushima Daiichi Nuclear Power Plant].

PubMed

Yuan, Jun; Sera, Koichiro; Takatsuji, Toshihiro

2015-01-01

To investigate human health effects of radiation exposure due to possible future nuclear accidents in distant places and other various findings of analysis of the radioactive materials contaminating the atmosphere of Nagasaki due to the Fukushima Daiichi Nuclear Power Plant accident. The concentrations of radioactive materials in aerosols in the atmosphere of Nagasaki were measured using a germanium semiconductor detector from March 2011 to March 2013. Internal exposure dose was calculated in accordance with ICRP Publ. 72. Air trajectories were analyzed using NOAA and METEX web-based systems. (134)Cs and (137)Cs were repeatedly detected. The air trajectory analysis showed that (134)Cs and (137)Cs flew directly from the Fukushima Daiichi Nuclear Power Plant from March to April 2011. However, the direct air trajectories were rarely detected after this period even when (134)Cs and (137)Cs were detected after this period. The activity ratios ((134)Cs/(137)Cs) of almost all the samples converted to those in March 2011 were about unity. This strongly suggests that the (134)Cs and (137)Cs detected mainly originated from the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Although the (134)Cs and (137)Cs concentrations per air volume were very low and the human health effects of internal exposure via inhalation is expected to be negligible, the specific activities (concentrations per aerosol mass) were relatively high. It was found that possible future nuclear accidents may cause severe radioactive contaminations, which may require radiation exposure control of farm goods to more than 1000 km from places of nuclear accidents.

Elevated fructosamine concentrations caused by IgA paraproteinemia in two dogs

PubMed Central

Kleiter, Miriam; Wolfesberger, Birgitt; Schwendenwein, Ilse; Miller, Ingrid

2010-01-01

An 8-year-old male Austrian Pinscher and a 14-year-old male Golden Retriever were presented for evaluation due to unexplainable high fructosamine values despite euglycemia and epistaxis in combination with polydipsia/polyuria, respectively. Blood analysis revealed severe hyperglobulinemia, hypoalbuminemia and markedly elevated fructosamine concentrations in both dogs. Multiple myeloma with IgA-monoclonal gammopathy was diagnosed by serum and urine electrophoresis including immunodetection with an anti-dog IgA antibody and bone marrow aspirations. Diabetes mellitus was excluded by repeated plasma and urine glucose measurements. Fructosamine values were positively correlated with globulin, but negatively correlated with albumin concentrations. These cases suggest that, as in human patients, monoclonal IgA gammopathy should be considered as a possible differential diagnosis for dogs with high fructosamine concentrations. PMID:21113108

77 FR 16251 - Announcement of Funding Awards, HOPE VI Revitalization Grant Program, Fiscal Year 2010

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-20

... or decrease the concentration of very low-income families; and (4) build sustainable communities. The... assistance due to the need to award the FY2011 appropriation to communities as soon as possible and the fact... 22,000,000.00 Fairfax Gardens. Street, Suite B, Taunton, MA 02780-4141. 4 Housing Authority of the...

Arsenic residue in the products and by-products of chicken and ducks: a possible concern of avian health and environmental hazard to the population in West Bengal, India.

PubMed

Rana, Tanmoy; Bera, Asit Kumar; Mondal, Dipak Kumar; Das, Subhashree; Bhattacharya, Debasis; Samanta, Srikanta; Pan, Diganta; Das, Subrata Kumar

2014-07-01

Arsenicosis caused due to drinking of arsenic contaminated ground water is a major environmental health hazard throughout the world. We evaluated the ecotoxicological effect of arsenic on chicken and duck in an arsenic endemic zone. The concentration of arsenic was higher in chicken and duck feed and their by-products than that in the respective samples of control area. Arsenic concentration in the eggs of both chicken and duck was higher than that in the respective samples of control area. Thus, we concluded that arsenic enters into food chain through the intake of contaminated eggs. Furthermore, adverse health effect of arsenic on avian population is due to the alteration in haematobiochemical indices. © The Author(s) 2012.

Local characteristics of cross-unit contamination around high-rise building due to wind effect: mean concentration and infection risk assessment.

PubMed

Liu, X P; Niu, J L; Kwok, K C S; Wang, J H; Li, B Z

2011-08-15

In this present work, the characteristics of hazardous gas dispersion and possible cross-unit contamination around a complex-shaped high-rise residential building due to wind effect are thoroughly studied using physical modeling method. Experiments were performed in a boundary layer wind tunnel for a 1:30 scale model that represented a 10-story residential building in prototype. Tracer gas, simulating exhausted room air, was continuously released from different floor levels, and its concentrations on the adjacent envelope surfaces were measured using fast flame ionization detectors. The mean concentration fields were reported and analyzed under different configurations during the experiment to consider the effects on pollutant dispersion behavior due to changes in source position and approaching wind condition, with the main emphasis on the differences between open-window and closed-window conditions. In particular, the measured concentration fields were further examined from a practical point of view, with respect to hazard assessment. Understanding these hazardous plume dispersion features is useful for employing effective intervention strategies in modern residential building environment in case of hazardous substance release. The study on this physical process is not only helpful to reduce the hazardous effect of routine release of harmful pollutant near the building, but also useful for the purpose of prevention and control of accidental infectious diseases outbreak. Copyright © 2011 Elsevier B.V. All rights reserved.

Uranium hydrogeochemical and stream sediment reconnaissance of the Arminto NTMS quadrangle, Wyoming, including concentrations of forty-three additional elements

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

Morgan, T.L.

1979-11-01

During the summers of 1976 and 1977, 570 water and 1249 sediment samples were collected from 1517 locations within the 18,000-km/sup 2/ area of the Arminto NTMS quadrangle of central Wyoming. Water samples were collected from wells, springs, streams, and artifical ponds; sediment samples were collected from wet and dry streams, springs, and wet and dry ponds. All water samples were analyzed for 13 elements, including uranium, and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit to 84.60 parts per billion (ppb) with a meanmore » of 4.32 ppb. All water sample types except pond water samples were considered as a single population in interpreting the data. Pond water samples were excluded due to possible concentration of uranium by evaporation. Most of the water samples containing greater than 20 ppb uranium grouped into six clusters that indicate possible areas of interest for further investigation. One cluster is associated with the Pumpkin Buttes District, and two others are near the Kaycee and Mayoworth areas of uranium mineralization. The largest cluster is located on the west side of the Powder River Basin. One cluster is located in the central Big Horn Basin and another is in the Wind River Basin; both are in areas underlain by favorable host units. Uranium concentrations in sediment samples range from 0.08 parts per million (ppm) to 115.50 ppm with a mean of 3.50 ppm. Two clusters of sediment samples over 7 ppm were delineated. The first, containing the two highest-concentration samples, corresponds with the Copper Mountain District. Many of the high uranium concentrations in samples in this cluster may be due to contamination from mining or prospecting activity upstream from the sample sites. The second cluster encompasses a wide area in the Wind River Basin along the southern boundary of the quadrangle.« less

Application of solid phase extraction procedures for rare earth elements determination in environmental samples.

PubMed

Pyrzynska, Krystyna; Kubiak, Anna; Wysocka, Irena

2016-07-01

Determination of rare earth elements in environmental samples requires often pre-concentration and separation step due to a low metal content and high concentration of the interfering matrix components. A solid phase extraction technique with different kind of solid sorbents offers a high enrichment factor, rapid phase separation and the possibility of its combination with various detection techniques used either in on-line or off-line mode. The recent developments in this area published over the last five years are presented and discussed in this paper. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of oxygen-vacancy complex /A center/ on piezoresistance of n-type silicon.

NASA Technical Reports Server (NTRS)

Littlejohn, M. A.; Loggins, C. D., Jr.

1972-01-01

Changes in both magnitude and temperature dependence of the piezoresistance of electron-irradiated n-type silicon, induced by the latter's oxygen-vacancy complex (A center), are shown to be due to the fact that the presence of the A center causes the total conduction-band electron concentration to change with an applied stress. This change in electron concentration leads to an additional piezoresistance contribution that is expected to be important in certain many-valley semiconductors. This offers the possibility of tailoring the thermal variations of semiconductor mechanical sensors to more desirable values over limited temperature ranges.

Measuring Cytokine Concentrations Using Magnetic Spectroscopy of Nanoparticle Brownian Relaxation

NASA Astrophysics Data System (ADS)

Khurshid, Hafsa; Shi, Yipeng; Weaver, John

The magnetic particle spectroscopy is a newly developed non-invasive technique for obtaining information about the nanoparticles' micro environment. In this technique the nanoparticles' magnetization, induced by an alternating magnetic field at various applied frequencies, is processed to analyze rotational freedom of nanoparticles. By analyzing average rotational freedom, it is possible to measure the nanoparticle's relaxation time, and hence get an estimate of the temperature and viscosity of the medium. In molecular concentration sensing, the rotational freedom indicates the number of nanoparticles that are bound by a selected analyte. We have developed microscopic nanoparticles probes to measure the concentration of selected molecules. The nanoparticles are targeted to bind the selected molecule and the resulting reduction in rotational freedom can be quantified remotely. Previously, sensitivity measurements has been reported to be of the factor of 200. However, with our newer perpendicular field setup (US Patent Application Serial No 61/721,378), it possible to sense cytokine concentrations as low as 5 Pico-Molar in-vitro. The excellent sensitivity of this apparatus is due to isolation of the drive field from the signal so the output can be amplified to a higher level. Dartmouth College.

Spatial and Temporal Variations in Arsenic Exposure via Drinking-water in Northern Argentina

PubMed Central

Concha, Gabriela; Nermell, Barbro

2006-01-01

This study evaluated the spatial, temporal and inter-individual variations in exposure to arsenic via drinking-water in Northern Argentina, based on measurements of arsenic in water, urine, and hair. Arsenic concentrations in drinking-water varied markedly among locations, from <1 to about 200 μg/L. Over a 10-year period, water from the same source in San Antonio de los Cobres fluctuated within 140 and 220 μg/L, with no trend of decreasing concentration. Arsenic concentrations in women's urine (3–900 μg/L, specific weight 1.018 g/mL) highly correlated with concentrations in water on a group level, but showed marked variations between individuals. Arsenic concentrations in hair (range 20–1,500 μg/kg) rather poorly correlated with urinary arsenic, possibly due to external contamination. Thus, arsenic concentration in urine seems to be a better marker of individual arsenic exposure than concentrations in drinking-water and hair. PMID:17366773

A time dependent mixing model to close PDF equations for transport in heterogeneous aquifers

NASA Astrophysics Data System (ADS)

Schüler, L.; Suciu, N.; Knabner, P.; Attinger, S.

2016-10-01

Probability density function (PDF) methods are a promising alternative to predicting the transport of solutes in groundwater under uncertainty. They make it possible to derive the evolution equations of the mean concentration and the concentration variance, used in moment methods. The mixing model, describing the transport of the PDF in concentration space, is essential for both methods. Finding a satisfactory mixing model is still an open question and due to the rather elaborate PDF methods, a difficult undertaking. Both the PDF equation and the concentration variance equation depend on the same mixing model. This connection is used to find and test an improved mixing model for the much easier to handle concentration variance. Subsequently, this mixing model is transferred to the PDF equation and tested. The newly proposed mixing model yields significantly improved results for both variance modelling and PDF modelling.

Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

NASA Astrophysics Data System (ADS)

Campbell, J. M.; Jordan, P.; Arnscheidt, J.

2015-01-01

This study reports the use of high-resolution water quality monitoring to assess the influence of changes in land use management on total phosphorus (TP) transfers in two 5 km2 agricultural sub-catchments. Specifically, the work investigates the issue of agricultural soil P management and subsequent diffuse transfers at high river flows over a 5-year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STSs) and mitigation efforts - a key concern for catchment management. Results showed an inconsistent response to soil P management over 5 years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STSs) and also to gauge their effectiveness.

Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

NASA Astrophysics Data System (ADS)

Campbell, J. M.; Jordan, P.; Arnscheidt, J.

2014-09-01

This study reports the use of high resolution water quality monitoring to assess the influence of changes in landuse management on total phosphorus (TP) transfers in two 5 km2 agricultural sub-catchments. Specifically, the work investigates the "wicked problem" of agricultural soil P management and subsequent diffuse transfers at high river flows over a five year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STS) and mitigation efforts - here termed the "filthy issue" of rural catchment management. Results showed an inconsistent response to soil P management over five years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STS) and also to gauge their effectiveness.

Optical nonlinearity of CdSe-PMMA hybrid nanocomposite investigated via Z-scan technique and semi-empirical relations

NASA Astrophysics Data System (ADS)

Kaur, Ramneek; Tripathi, S. K.

2016-04-01

CdSe-PMMA nanocomposite has been synthesized by ex-situ technique. The effect of different Ag doping concentrations on its structural and optical properties has been studied. X-ray diffraction reveals the hexagonal wurtzite structure of the polymer nanocomposites with preferential growth of the nanocrystals along (1 0 0) direction. Transmission electron micrograph shows the spherical CdSe nanoparticles embedded in polymer matrix. The nonlinear refractive index of the nanocomposites has been calculated using Tichy & Ticha semi-empirical relations and Z-scan technique. Z-scan results disclose the two photon absorption process in the hybrid nanocomposites with self focussing behaviour. With Ag doping, the nonlinearity is found to be increased up to 0.2% Ag doping concentration due to the confined effect of Surface Plasmon, Quantum confinement and thermal lensing. Above 0.2% Ag concentration, its value decreases due to the declined linear refractive index of the nanocomposites. Maximum two photon figure of merit is 76 for 0.2% Ag doped CdSe-PMMA hybrid nanocomposite. The present results accentuate the possibility of tuning the optical non-linearity of CdSe-PMMA hybrid nanocomposite by adjusting the doping concentration.

To survive or to slay

PubMed Central

2009-01-01

The ecological relevance of allelopathy is highly debated due to the lack of phytotoxic concentrations of allelochemical in natural field conditions. Most of the putative allelochemicals are exuded at low concentrations, and subsequently undergo rapid chemical and biological degradation in soil matrices. At sub-toxic concentrations, due to hormesis effect, these compounds could possibly have a stimulatory effect on plant growth. Many of the suggested allelopathic compounds are chelants and can complex-with and mobilize metal ions in soil. These complexation reactions will detoxify the compound, but will increase the chemical-nutrient-foraging ability of the donor plant. The concentration in which these compounds are exuded matches with other similar secondary metabolites facilitating plant nutrient acquisition. Irrespective of whether the implicated PSMs facilitate donor plant in chemical nutrient-foraging or in poisoning the neighbors, the conferred advantage translates in terms of resource availability—in first case the donor enjoys uncontested nutrient uptake efficiency, where as in the latter the donor gain an uncontested access to resources. This further reaffirms the notion that resource competition and allelopathy are inextricable. Since most of the secondary metabolites could mobilize nutrients from soil, along with its phytotoxic effect, complementary self-facilitation roles of these compounds should be investigated. PMID:19820349

The effect of chlorpyrifos upon ATPase activity of sarcoplasmic reticulum and biomechanics of skeleta l muscle contraction.

PubMed

Nozdrenko, D M; Miroshnychenko, M S; Soroca, V M; Korchins ka, L V; Zavodovskiy, D O

2016-01-01

We investigated the effect of chlorpyrifos, an organophosphate insecticide, on Ca2+,Mg2+-ATPase activity of sarcoplasmic reticulum and on contraction dynamics (force and length changes) of Rana temporaria m. tibialis anterior muscle fiber bundles. All of the used concentrations of chlorpyrifos (10-6 to 10-5 M) caused decrease of Ca2+,Mg2+-ATPase activity. The inhibition of Ca2+,Mg2+-ATPase activity by chlorpyriphos in concentrations of 10-6 M to 7.5·10-6 M is due to permeation of sarcoplasmic reticulum rather than due to direct enzyme inhibition by organophosphate insecticides. The inhibitory properties of the compound were higher at increased concentration and exposure timeframes. Chlorpyrifos in concentration range of 10-6 to 7.5·10-6 M causes changes in muscle fiber response force that were more pronounced than changes in contractile length. We demonstrated inhibition of Ca2+,Mg2+-ATPase activity caused by noncholinergic effects of chlorpyriphos. It is possible to conclude that influence of organophosphate insecticides happens not only in the neuromuscular transmission but also on the level of subcellular structures.

Modelling pollutants dispersion and plume rise from large hydrocarbon tank fires in neutrally stratified atmosphere

NASA Astrophysics Data System (ADS)

Argyropoulos, C. D.; Sideris, G. M.; Christolis, M. N.; Nivolianitou, Z.; Markatos, N. C.

2010-02-01

Petrochemical industries normally use storage tanks containing large amounts of flammable and hazardous substances. Therefore, the occurrence of a tank fire, such as the large industrial accident on 11th December 2005 at Buncefield Oil Storage Depots, is possible and usually leads to fire and explosions. Experience has shown that the continuous production of black smoke from these fires due to the toxic gases from the combustion process, presents a potential environmental and health problem that is difficult to assess. The goals of the present effort are to estimate the height of the smoke plume, the ground-level concentrations of the toxic pollutants (smoke, SO 2, CO, PAHs, VOCs) and to characterize risk zones by comparing the ground-level concentrations with existing safety limits. For the application of the numerical procedure developed, an external floating-roof tank has been selected with dimensions of 85 m diameter and 20 m height. Results are presented and discussed. It is concluded that for all scenarios considered, the ground-level concentrations of smoke, SO 2, CO, PAHs and VOCs do not exceed the safety limit of IDLH and there are no "death zones" due to the pollutant concentrations.

Portable Chemical Agent Detection System: Differential Reflectometer and Light Scattering Approaches

DTIC Science & Technology

2005-02-15

possible to conduct elemental analysis on modified capillaries because of the polymer coating. Instead, measurements of electroosmotic flow were used...design There are several essential requirements for a sensitive chemiluminescence cell (Figure 1); good reagent/analyte mixing for maximum photon yield...Cutaway of Chemiluminescence cell the cooled pint housing. In our design, the concentric inlets will increase photon collection due to better mixing of

Entropy production during hadronization of a quark-gluon plasma

NASA Astrophysics Data System (ADS)

Biró, Tamás S.; Schram, Zsolt; Jenkovszky, László

2018-02-01

We revisit some physical pictures for the hadronization of quark-gluon plasma, concentrating on the problem of entropy production during processes where the number of degrees of freedom is seemingly reduced due to color confinement. Based on observations on Regge trajectories we propose not having an infinite tower of hadronic resonances. We discuss possible entropy production mechanisms far from equilibrium in terms of stochastic dynamics.

The prevalence and pathogenesis of naturally-occurring Haemonchus longistipes infection in Sudanese camels.

PubMed

Arzoun, I H; Hussein, H S; Hussein, M F

1984-04-01

Camel haemonchosis is prevalent in the Sudan, especially during the rainy season, with a decrease in prevalence in the dry season possibly due to delayed maturation of the worms. The naturally occurring disease in Sudanese camels is characterized by emaciation, anaemia, oedema of the lower parts of the limbs, eosinophilia, hypoproteinaemia, hypoalbuminaemia, hyperglobulinaemia and eosinophilia, as well as elevated blood urea concentrations.

Space Flows and Disturbances Due to Bodies in Motion Through the Magnetoplasma

NASA Astrophysics Data System (ADS)

Ponomarjov, Maxim G.

2000-10-01

In this paper a method is concerned which makes it possible to describe numerically and analytically the most famous structures in the non-equilibrium ionosphere, such as stratified and yacht sail like structures, flute jets, wakes and clouds. These problems are of practical interest in space sciences, astrophysics and in turbulence theory, and also of fundamental interest since they enable one to concentrate on the effects of the ambient electric and magnetic fields. Disturbances of charged particle flows due to the ambient flow interactions with bodies are simulated with taking into account the ambient magnetic field effect. The effects of interactions between solid surfaces and the flows was simulated by making use of an original image method. The flow disturbances were described by the Boltzmann equation. In the case of the ambient homogeneous magnetic field the Boltzmann equation is solved analytically. The case of diffuse reflection of particles by surface is considered in detail. The disturbances of charged particle concentration are calculated in 3D space. The contours of constant particle concentration obtained from numerical simulations illustrate the dynamics of developing stratifications and flute structures in charged particle jets and wakes under the ambient magnetic field effect. The basic goal of this paper is to present the method and to demonstate its possibility for simulations of turbulence, plasma jets, wakes and clouds in the ionosphere and Space when effects of electric and magnetic fields are taken into account.

A complex effect of arsenite on the formation of alpha-ketoglutarate in rat liver mitochondria.

PubMed

Lenartowicz, E

1990-12-01

This investigation presents disturbances of the mitochondrial metabolism by arsenite, a hydrophilic dithiol reagent known as an inhibitor of mitochondrial alpha-keto acid dehydrogenases. Arsenite at concentrations of 0.1-1.0 mM was shown to induce a considerable oxidation of intramitochondrial NADPH, NADH, and glutathione without decreasing the mitochondrial membrane potential. The oxidation of NAD(P)H required the presence of phosphate and was sensitive to ruthenium red, but occurred without the addition of calcium salts. Mitochondrial reactions producing alpha-ketoglutarate from glutamate and isocitrate were modulated by arsenite through various mechanisms: (i) both glutamate transaminations, with oxaloacetate and with pyruvate, were inhibited by accumulating alpha-ketoglutarate; however, at low concentrations of alpha-ketoglutarate the aspartate aminotransferase reaction was stimulated due to the increase of NAD+ content; (ii) the oxidation of isocitrate was stimulated at its low concentration only, due to the oxidation of NADPH and NADH; this oxidation was prevented by concentrations of citrate or isocitrate greater than 1 mM; (iii) the conversion of isocitrate to citrate was suppressed, presumably as a result of the decrease of Mg2+ concentration in mitochondria. Thus the depletion of mitochondrial vicinal thiol groups in hydrophilic domains disturbs the mitochondrial metabolism not only by the inhibition of alpha-keto acid dehydrogenases but also by the oxidation of NAD(P)H and, possibly, by the change in the ion concentrations.

Determining the transport mechanism of an enzyme-catalytic complex metabolic network based on biological robustness.

PubMed

Wang, Lei

2013-04-01

Understanding the transport mechanism of 1,3-propanediol (1,3-PD) is of critical importance to do further research on gene regulation. Due to the lack of intracellular information, on the basis of enzyme-catalytic system, using biological robustness as performance index, we present a system identification model to infer the most possible transport mechanism of 1,3-PD, in which the performance index consists of the relative error of the extracellular substance concentrations and biological robustness of the intracellular substance concentrations. We will not use a Boolean framework but prefer a model description based on ordinary differential equations. Among other advantages, this also facilitates the robustness analysis, which is the main goal of this paper. An algorithm is constructed to seek the solution of the identification model. Numerical results show that the most possible transport way is active transport coupled with passive diffusion.

Roundup Ready soybean gene concentrations in field soil aggregate size classes.

PubMed

Levy-Booth, David J; Gulden, Robert H; Campbell, Rachel G; Powell, Jeff R; Klironomos, John N; Pauls, K Peter; Swanton, Clarence J; Trevors, Jack T; Dunfield, Kari E

2009-02-01

Roundup Ready (RR) soybeans containing recombinant Agrobacterium spp. CP4 5-enol-pyruvyl-shikimate-3-phosphate synthase (cp4 epsps) genes tolerant to the herbicide glyphosate are extensively grown worldwide. The concentration of recombinant DNA from RR soybeans in soil aggregates was studied due to the possibility of genetic transformation of soil bacteria. This study used real-time PCR to examine the concentration of cp4 epsps in four field soil aggregate size classes (>2000 microm, 2000-500 microm, 500-250 microm and <250 microm). Aggregates over 2000 microm in diameter had significantly greater gene concentrations than those with diameters under 2000 microm. The >2000 mum fraction contained between 66.62% and 99.18% of total gene copies, although it only accounted for about 30.00% of the sampled soil. Aggregate formation may facilitate persistence of recombinant DNA.

Time trend of butyl- and phenyl-tin contamination in organisms of the Lagoon of Venice (1999-2003).

PubMed

Zanon, F; Rado, N; Centanni, E; Zharova, N; Pavoni, B

2009-05-01

In the period 1999-2003 a monitoring study on the accumulation of organotin compounds in edible organisms in the Lagoon of Venice was conducted. Butyl and Phenyl derivatives were determined in pooled samples of Mytilus galloprovincialis and Tapes spp. with the aims of assessing organotin contamination in the Lagoon of Venice in the period just preceding their ban in Europe, monitoring the concentrations in organisms with a high commercial use, evaluating a potential hazard for human health due to seafood and identifying the possible contamination sources. Sampling stations (up to 20) were distributed around the Lagoon and particularly concentrated in the area close to the town of Chioggia. Significantly higher (analysis of variance (ANOVA), p < 0.05) tributyltin (TBT) concentrations were found in mussels (from 38 +/- 8 to 6,666 +/- 1,333 microg kg(-1) d.w., as TBT(+)), than in clams (from 6 +/- 1 to 2,256 +/- 451 microg kg(-1) d.w., as TBT(+)). During the 3 years of the survey no increase in average concentrations of the butyltin compounds (tributyltin (TBT) + dibutyltin (DBT) + monobutyltin (MBT)) was observed (ANOVA, p > 0.05) in either species. Furthermore, by analyzing the entire data set, it is evident that most stations show analogous concentrations in the 3 years for both species, whereas few have anomalously higher concentrations. If organotin concentrations in specimens from some sites are compared with the Tolerable Average Residue Level, a possible risk for human health must be considered.

Assessment of chloroethene degradation rates based on ratios of daughter/parent compounds in groundwater plumes

NASA Astrophysics Data System (ADS)

Höhener, Patrick

2014-05-01

Chlorinated solvent spills at industrial and urban sites create groundwater plumes where tetrachloro- and trichloroethene may degrade to their daughter compounds, dichloroethenes, vinyl chloride and ethane. The assessment of degradation and natural attenuation at such sites may be based on the analysis and inverse modelling of concentration data, on the calculation of mass fluxes in transsects, and/or on the analysis of stable isotope ratios in the ethenes. Relatively few work has investigated the possibility of using ratio of concentrations for gaining information on degradation rates. The use of ratios bears the advantage that dilution of a single sample with contaminant-free water does not matter. It will be shown that molar ratios of daughter to parent compounds measured along a plume streamline are a rapid and robust mean of determining whether degradation rates increase or decrease along the degradation chain, and allow furthermore a quantitation of the relative magnitude of degradation rates compared to the rate of the parent compound. Furthermore, ratios of concentration will become constant in zones where degradation is absent, and this allows to sketching the extension of actively degrading zones. The assessment is possible for pure sources and also for mixed sources. A quantification method is proposed in order to estimate first-order degradation rates in zones of constant degradation activity. This quantification method includes corrections that are needed due to longitudinal and transversal dispersivity. The method was tested on a number of real field sites from literature. At the majority of these sites, the first-order degradation rates were decreasing along the degradation chain from tetrachloroethene to vinyl chloride, meaning that the latter was often reaching important concentrations. This is bad news for site owners due to the increased toxicity of vinyl chloride compared to its parent compounds.

[Fatal outcome of an hydrogen sulfide poisoning].

PubMed

Querellou, E; Jaffrelot, M; Savary, D; Savry, C; Perfus, J-P

2005-10-01

We report a case of fatal outcome poisoning by massive exposure to hydrogen sulfide of a sewer worker. This rare event was associated with a moderate intoxication of two members of the rescue team. The death was due to asystole and massive lung oedema. Autopsy analysis showed diffuse necrotic lesions in lungs. Hydrogen sulfide is a direct and systemic poison, produced by organic matter decomposition. The direct toxicity mechanism is still unclear. The systemic toxicity is due to an acute toxicity by oxygen depletion at cellular level. It is highly diffusable and potentially very dangerous. At low concentration, rotten egg smell must trigger hydrogen sulfide suspicion since at higher concentration it is undetectable, making intoxication possible. In case of acute intoxication, there is an almost instantaneous cardiovascular failure and a rapid death. Hydrogen sulfide exposure requires prevention measures and more specifically the use of respiratory equipment for members of the rescue team.

Plants as useful vectors to reduce environmental toxic arsenic content.

PubMed

Mirza, Nosheen; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Sultan, Sikander

2014-01-01

Arsenic (As) toxicity in soil and water is an increasing menace around the globe. Its concentration both in soil and environment is due to natural and anthropogenic activities. Rising arsenic concentrations in groundwater is alarming due to the health risks to plants, animals, and human beings. Anthropogenic As contamination of soil may result from mining, milling, and smelting of copper, lead, zinc sulfide ores, hide tanning waste, dyes, chemical weapons, electroplating, gas exhaust, application of municipal sludge on land, combustion of fossil fuels, As additives to livestock feed, coal fly ash, and use of arsenical pesticides in agricultural sector. Phytoremediation can be viewed as biological, solar-driven, pump-and-treat system with an extensive, self-extending uptake network (the root system) that enhances the natural ecosystems for subsequent productive use. The present review presents recent scientific developments regarding phytoremediation of arsenic contaminated environments and its possible detoxification mechanisms in plants.

Plants as Useful Vectors to Reduce Environmental Toxic Arsenic Content

PubMed Central

Mirza, Nosheen; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Sultan, Sikander

2014-01-01

Arsenic (As) toxicity in soil and water is an increasing menace around the globe. Its concentration both in soil and environment is due to natural and anthropogenic activities. Rising arsenic concentrations in groundwater is alarming due to the health risks to plants, animals, and human beings. Anthropogenic As contamination of soil may result from mining, milling, and smelting of copper, lead, zinc sulfide ores, hide tanning waste, dyes, chemical weapons, electroplating, gas exhaust, application of municipal sludge on land, combustion of fossil fuels, As additives to livestock feed, coal fly ash, and use of arsenical pesticides in agricultural sector. Phytoremediation can be viewed as biological, solar-driven, pump-and-treat system with an extensive, self-extending uptake network (the root system) that enhances the natural ecosystems for subsequent productive use. The present review presents recent scientific developments regarding phytoremediation of arsenic contaminated environments and its possible detoxification mechanisms in plants. PMID:24526924

Ammonia Diffusion through Nalophan Double Bags: Effect of Concentration Gradient Reduction

PubMed Central

Capelli, Laura; Boiardi, Emanuela; Del Rosso, Renato

2014-01-01

The ammonia loss through Nalophan bags has been studied. The losses observed for storage conditions and times as allowed by the reference standard for dynamic olfactometry (EN 13725:2003) indicate that odour concentration values due to the presence of small molecules may be significantly underestimated if samples are not analysed immediately after sampling. A diffusion model was used in order to study diffusion through the bag. The study discusses the effect of concentration gradient (ΔC) across the polymeric membrane of the analyte. The ΔC was controlled by using a setup bag called “double bags.” Experimental data show a reduction of ammonia percentage losses due to the effect of the external multibarrier. The expedient of the double bag loaded with the same gas mixture allows a reduced diffusion of ammonia into the inner bag. Comparing the inner bag losses with those of the single bag stored in the same conditions (T, P, u) and with equal geometrical characteristics (S/V, z), it was observed that the inner bag of the double bag displays a 16% loss while the single bag displays a 37% loss. Acting on the ΔC it is possible to achieve a gross reduction of 57% in the ammonia leakage due to diffusion. PMID:25506608

A Study of the Relationship Between Anthropogenic Sulfate and Cloud Drop Nucleation

NASA Technical Reports Server (NTRS)

Chuang, Catherine C.; Penner, Joyce E.

1994-01-01

The characteristics of the cloud drop size distribution near cloud base are initially determined by the aerosol particles that serve as CCN and by the local updraft velocity. Chemical reactions of the emitted gaseous sulfur compounds due to human activities will alter, through gas-to-particle conversion, the aerosol size distribution, total number, and its chemical composition. Recently, Boucher and Rodhe and Jones et.al have each developed parameterizations relating cloud drop concentration to sulfate mass or aerosol number concentration, respectively, and used them to develop estimates of the indirect forcing by anthropogenic sulfate aerosols. THese parameterizations made use of measure relationships in continental and maritime clouds. However, these relationships are inherently noisy, yielding more than a factor of 2 variation in cloud drop concentration for a given aerosol number (or for a given sulfate mass) concentration. The large spatial and temporal variabilities in the concentration, chemical characteristics, and size distribution of aerosols have made it difficult to develop such a parameterization from data. In this paper, our focus is to develop a means for relating the predicted anthropogenic sulfate mass to cloud drop number concentration over the range of expected conditions associated with continental and marine aerosol. We start with an assumed pre-existing particle size distribution and develop an approximation of the altered distribution after addition of anthropogenic sulfate. We thereby develop a conservative estimate of the possible change in cloud drop number concentration due to anthropogenic sulfate.

Complex Networks in Different Languages: A Study of an Emergent Multilingual Encyclopedia

NASA Astrophysics Data System (ADS)

Pembe, F. Canan; Bingol, Haluk

There is an increasing interest to the study of complex networks in an interdisciplinary way. Language, as a complex network, has been a part of this study due to its importance in human life. Moreover, the Internet has also been at the center of this study by making access to large amounts of information possible. With these ideas in mind, this work aims to evaluate conceptual networks in different languages with the data from a large and open source of information in the Internet, namely Wikipedia. As an evolving multilingual encyclopedia that can be edited by any Internet user, Wikipedia is a good example of an emergent complex system. In this paper, different from previous work on conceptual networks which usually concentrated on single languages, we concentrate on possible ways to compare the usages of different languages and possibly the underlying cultures. This also involves the analysis of local network properties around certain coneepts in different languages. For an initial evaluation, the concept "family" is used to compare the English and German Wikipedias. Although, the work is currently at the beginning, the results are promising.

Fluorescence Correlation Spectroscopy at Micromolar Concentrations without Optical Nanoconfinement

DOE PAGES

Laurence, Ted A.; Ly, Sonny; Bourguet, Feliza; ...

2014-08-14

Fluorescence correlation spectroscopy (FCS) is an important technique for studying biochemical interactions dynamically that may be used in vitro and in cell-based studies. It is generally claimed that FCS may only be used at nM concentrations. We show that this general consensus is incorrect and that the limitation to nM concentrations is not fundamental but due to detector limits as well as laser fluctuations. With a high count rate detector system and applying laser fluctuation corrections, we demonstrate FCS measurements up to 38 μM with the same signal-to-noise as at lower concentrations. Optical nanoconfinement approaches previously used to increase themore » concentration range of FCS are not necessary, and further increases above 38 μM may be expected using detectors and detector arrays with higher saturation rates and better laser fluctuation corrections. This approach greatly widens the possibilities of dynamic measurements of biochemical interactions using FCS at physiological concentrations.« less

Modelling the fate of micropollutants in the marine environment using passive sampling.

PubMed

Claessens, Michiel; De Laender, Frederik; Monteyne, Els; Roose, Patrick; Janssen, Colin R

2015-07-15

Polydimethylsiloxane sheets were used to determine freely dissolved concentrations (C(diss)) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the Belgian coastal zone. Equilibrium models were used to predict the whole water concentrations (C(ww)) of these compounds as well as their concentrations in sediment, suspended particulate matter (SPM) and biota. In general, contaminant concentrations were predicted well for whole water and biota. C(ww) was increasingly underpredicted as K(oc) increased, possibly because of the presence of black carbon. Concentrations in biota were overestimated by the equilibrium approach when logK(ow) exceeded 6.5, suggesting an increasing role of transformation processes. Concentrations of PAHs and PCBs in sediment and SPM were consistently underpredicted although a good correlation between measured and predicted values was observed. This was potentially due to the use of experimental K(oc) values which have been found to underestimate partitioning of hydrophobic substances to sediment in field studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigation of potentially toxic heavy metals in different organic wastes used to fertilize market garden crops.

PubMed

Tella, M; Doelsch, E; Letourmy, P; Chataing, S; Cuoq, F; Bravin, M N; Saint Macary, H

2013-01-01

The benefits of using organic waste as fertilizer and soil amendment should be assessed together with the environmental impacts due to the possible presence of heavy metals (HMs). This study involved analysing major element and HM contents in raw and size-fractionated organic wastes (17 sewage sludges and composts) from developed and developing countries. The overall HM concentration pattern showed an asymmetric distribution due to the presence of some wastes with extremely high concentrations. HM concentrations were correlated with the size of cities or farms where the wastes had been produced, and HM were differentiated with respect to their origins (geogenic: Cr-Ni; anthropogenic agricultural and urban: Cu-Zn; anthropogenic urban: Cd-Pb). Size fractionation highlighted Cd, Cu, Zn and Pb accumulation in fine size fractions, while Cr and Ni were accumulated in the coarsest. HM associations with major elements revealed inorganic (Al, Fe, etc.) bearing phases for Cr and Ni, and sulfur or phosphorus species for Cd, Cu Pb and Zn. Copyright © 2012 Elsevier Ltd. All rights reserved.

Variation in hemoglobin concentration among samples of high-altitude natives in the Andes and the Himalayas.

PubMed

Beall, Cynthia M; Brittenham, Gary M; Macuaga, Francisco; Barragan, Mario

1990-01-01

This paper presents data on hemoglobin concentration in a rural Andean sample at 3,800-3,900 m and incorporates them into a review intended to evaluate possible sources of the range of variation in mean hemoglobin concentration among samples obtained at high altitude. Between 3,400 and 4,000 m, rural Himalayan highlanders average 1.4 gm/dl lower mean hemoglobin concentration than rural Andean highlanders. With respect to potential causes of anemia, it is concluded that the relatively low values of rural Himalyan populations are not explicable by lower hypoxic stress or different techniques of obtaining and analyzing blood samples and are probably not explicable by nutritional deficiency and disease. With respect to potential causes of polycythemia within Andean populations, it is concluded that the somewhat higher values of some mining and urban samples of Andean higlanders may not be due to the mining occupation per se but may be due partly to the inclusion of European and mestizo (with at most 500 years of high-altitude ancestry) along with Amerindian highlanders (with millenia of high-altitude ancestry) as well as to the inclusion of highlanders living well above their own habitual altitudes of residence. The Andean polycythemia is probably not due to obesity, high androgen levels, or frequent intermittent hypoxemia during sleep. The effect of heavy smoking cannot be evaluated. Further work on hematological adaptation to high altitude must pay special attention to sample characteristics. Copyright © 1990 Wiley-Liss, Inc., A Wiley Company.

Thermal energy storage for CSP (Concentrating Solar Power)

NASA Astrophysics Data System (ADS)

Py, Xavier; Sadiki, Najim; Olives, Régis; Goetz, Vincent; Falcoz, Quentin

2017-07-01

The major advantage of concentrating solar power before photovoltaic is the possibility to store thermal energy at large scale allowing dispatchability. Then, only CSP solar power plants including thermal storage can be operated 24 h/day using exclusively the solar resource. Nevertheless, due to a too low availability in mined nitrate salts, the actual mature technology of the two tanks molten salts cannot be applied to achieve the expected international share in the power production for 2050. Then alternative storage materials are under studies such as natural rocks and recycled ceramics made from industrial wastes. The present paper is a review of those alternative approaches.

Nuclear chemistry of returned lunar samples: Nuclide analysis by gamma-ray spectrometry

NASA Technical Reports Server (NTRS)

Okelley, G. D.

1975-01-01

Primordial and cosmogenic radionuclide concentrations are determined nondestructively by gamma-ray spectrometry in soil and rock samples from the returned Apollo 17 sample collection from Taurus-Littrow and Descartes. Geochemical evidence in support of field geology speculation concerning layering of the subfloor basalt flows is demonstrated along with a possible correlation of magmatic fractionation of K/U as a function of depth. The pattern of radionuclide concentrations observed in these samples is distinct due to proton bombardment by the intense solar flares of August 4-9, 1972. Such radionuclide determinations are used in determining lunar sample orientation and characterizing solar flare activity.

On the possible origin of bulk third harmonic generation in skin cells

NASA Astrophysics Data System (ADS)

Su, Tung-Yu; Liao, Chien-Sheng; Yang, Chih-Yuan; Zhuo, Guan-Yu; Chen, Szu-Yu; Chu, Shi-Wei

2011-09-01

We studied third harmonic generation (THG) of melanin solution with concentrations similar to melanocytes in human skin. In contrast to conventional observation of THG at interface, bulk THG was detected inside the solution due to the formation of melanin hydrocolloids. A linear relationship between melanin concentration and THG intensity was found, suggesting THG originated from high-order hyper-Rayleigh scattering. By fitting this linear relationship, third-order hyperpolarizability of melanin hydrocolloids was determined to be three orders larger than that of water. Our result will be useful for interpretation of THG signals in skin and other tissues containing colloidal particles.

Nerolidol effects on mitochondrial and cellular energetics.

PubMed

Ferreira, Fernanda M; Palmeira, Carlos M; Oliveira, Maria M; Santos, Dario; Simões, Anabela M; Rocha, Sílvia M; Coimbra, Manuel A; Peixoto, Francisco

2012-03-01

In the present work, we evaluated the potential toxic effects of nerolidol, a sesquiterpenoid common in plants essential oils, both on mitochondrial and cellular energetics. Samples of enriched natural extracts of nerolidol (a racemic mixture of cis and trans isomers) were tested on rat liver mitochondria and a decrease in phosphorylative system was observed but not in the mitochondrial respiratory chain activity, which reflects a direct effect on F1-ATPase. Hence, respiratory control ratio was also decreased. Cellular ATP/ADP levels were significantly decreased in a concentration-dependent manner, possibly due to the direct effect of nerolidol on F(0)F(1)-ATPsynthase. Nerolidol stimulates respiratory activity probably due to an unspecific effect, since it does not show any protonophoric effect. Furthermore, we observed that mitochondrial permeability transition was delayed in the presence of nerolidol, possibly due to its antioxidant activity and because this compound decreases mitochondrial transmembrane electric potential. Our results also show that, in human hepatocellular liver carcinoma cell line (HepG2), nerolidol both induces cell death and arrests cell growth, probably related with the observed lower bioenergetic efficiency. Copyright © 2011 Elsevier Ltd. All rights reserved.

Sonochemical degradation of ofloxacin in aqueous solutions.

PubMed

Hapeshi, E; Achilleos, A; Papaioannou, A; Valanidou, L; Xekoukoulotakis, N P; Mantzavinos, D; Fatta-Kassinos, D

2010-01-01

The use of low frequency (20 kHz), high energy ultrasound for the degradation of the antibiotic ofloxacin in water was investigated. Experiments were performed with a horn-type ultrasound generator at varying applied power densities (130-640 W/L), drug concentrations (5-20 mg/L), hydrogen peroxide concentrations (0-100 mM) and sparging gases (air, oxygen, nitrogen and argon). In general, conversion (which was assessed following sample absorbance at 288 nm) increased with increasing ultrasound energy and peroxide concentration and decreasing initial drug concentration. Moreover, reactions under an argon atmosphere were faster than with diatomic gases, possibly due to argon's physical properties (e.g. solubility, thermal conductivity and specific heat ratio) favoring sonochemical activity. Overall, low to moderate levels of ofloxacin degradation were achieved (i.e. it never exceeded 50%), thus indicating that radical reactions in the liquid bulk rather than thermal reactions in the vicinity of the cavitation bubble are responsible for ofloxacin degradation.

Nanofluid flow and heat transfer in boundary layers: the influence of the concentration diffusion layer on heat transfer enhancement

NASA Astrophysics Data System (ADS)

Liu, Joseph T. C.; Barbosa Decastilho, Cintia Juliana; Fuller, Mark E.; Sane, Aakash

2017-11-01

The present work uses a perturbation procedure to deduce the small nanoparticle volume concentration conservation equations for momentum, heat and concentration diffusion. Thermal physical variables are obtained from conventional means (mixture and field theories) for alumina-water and gold-water nanofluids. In the case of gold-water nano fluid molecular dynamics results are used to estimate such properties, including transport coefficients. The very thin diffusion layer at large Schmidt numbers is found to have a great impact on the velocity and temperature profiles owing to their dependency on transport properties. This has a profound effect on the conduction surface heat transfer rate enhancement and skin friction suppression for the case of nano fluid concentration withdrawal at the wall, while the diffusional surface heat transfer rate is negligible due to large Schmidt numbers. Possible experimental directed at this interesting phenomenon is suggested.

Thermosolutal Marangoni convection short-time regimes - Proposals for drop tower experiments and real time computer simulation

NASA Astrophysics Data System (ADS)

Polezhaev, V. I.; Ermakov, M. K.

1992-12-01

Results are presented of a parametrical study of flow patterns, heat transfer, and time scales of thermosolutal Marangoni convection in a cavity with temperature and solutal gradients along the free surface and adiabatic bottom for the case of zero gravity. Nusselt number, concentration difference across the cavity, and flow/temperature fields for the different regimes are presented; they show the possibility to use Drop Tower 'Bremen' for measuring the developed secondary flow and heat/mass transfer due to thermosolutal Marangoni convection as well as the possibility to analyze and plan the drop tower for such experiments using the COMGA PC-based system.

18 years of continuous observation of tritium and atmospheric precipitations in Ramnicu Valcea (Romania): A time series analysis.

PubMed

Duliu, Octavian G; Varlam, Carmen; Shnawaw, Muataz Dheyaa

2018-05-16

To get more information on the origin of tritium and to evidence any possible presence of anthropogenic sources, between January 1999 and December 2016, the precipitation level and tritium concentration were monthly recorded and investigated by the Cryogenic Institute of Ramnicu Valcea, Romania. Compared with similar data covering a radius of about 1200 km westward, the measurements gave similar results concerning the time evolution of tritium content and precipitation level for the entire time interval excepting the period between 2009 and 2011 when the tritium concentrations showed a slight increase, most probable due to the activity of neighboring experimental pilot plant for tritium and deuterium separation. Regardless this fact, all data pointed towards a steady tendency of tritium concentrations to decrease with an annual rate of about 1.4 ± 0.05%. The experimental data on precipitation levels and tritium concentrations form two complete time series whose time series analysis showed, at p < 0.01, the presence of a single one-year periodicity whose coincident maximums which correspond to late spring - early summer months suggest the existence of the Spring Leak mechanism with a possible contribution of the soil moisture remobilization during the warm period. Copyright © 2018 Elsevier Ltd. All rights reserved.

Estimation of concentration of radionuclides in skeletal muscle from blood, based on the data from abandoned animals in Fukushima.

PubMed

Fukuda, Tomokazu

2018-06-01

The damage caused by the earthquake on 11 March, 2011 resulted in a serious nuclear accident in Japan. Due to the damage to the Fukushima Daiichi Nuclear Power Plant (FNPP), large amounts of radioactive substances were released into the environment. In particular, one of the largest safety concerns is radioactive cesium ( 134 Cs and 137 Cs). Due to the FNPP nuclear accident, a 20 km area was restricted from human activity, and various types of domestic animals were left in the zone. We collected the organs and tissues from sacrificed animals to obtain scientific data to evaluate the internal deposition of radioactive compounds. At first, we found there is a strong correlation between blood 137 Cs and organ 137 Cs with data from 44 cattle, indicating that skeletal muscle is the target organ of deposition of radioactive cesium. Second, we analyzed the relationship between blood 137 Cs and muscle 137 Cs within relatively lower radioactive concentration, suggesting that estimation of concentration of 137 Cs is possible from blood concentration of 137 Cs. Finally, we developed computer software to estimate the muscle 137 Cs concentration from blood samples. Our study contributes to the food safety of livestock products. © 2018 The Authors. Animal Science Journal published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Animal Science.

Reconnaissance of selected PPCP compounds in Costa Rican surface waters.

PubMed

Spongberg, Alison L; Witter, Jason D; Acuña, Jenaro; Vargas, José; Murillo, Manuel; Umaña, Gerardo; Gómez, Eddy; Perez, Greivin

2011-12-15

Eighty-six water samples were collected in early 2009 from Costa Rican surface water and coastal locations for the analysis of 34 pharmaceutical and personal care product compounds (PPCPs). Sampling sites included areas receiving treated and untreated wastewaters, and urban and rural runoff. PPCPs were analyzed using a combination of solid phase extraction and liquid chromatography tandem mass spectrometry. The five most frequently detected compounds were doxycycline (77%), sulfadimethoxine (43%), salicylic acid (41%), triclosan (34%) and caffeine (29%). Caffeine had the maximum concentration of 1.1 mg L(-1), possibly due to coffee bean production facilities upstream. Other compounds found in high concentrations include: doxycycline (74 μg L(-1)), ibuprofen (37 μg L(-1)), gemfibrozil (17 μg L(-1)), acetominophen (13 μg L(-1)) and ketoprofen (10 μg L(-1)). The wastewater effluent collected from an oxidation pond had similar detection and concentrations of compounds compared to other studies reported in the literature. Waters receiving runoff from a nearby hospital showed higher concentrations than other areas for many PPCPs. Both caffeine and carbamazepine were found in low frequency compared to other studies, likely due to enhanced degradation and low usage, respectively. Overall concentrations of PPCPs in surface waters of Costa Rica are inline with currently reported occurrence data from around the world, with the exception of doxycycline. Published by Elsevier Ltd.

Development of an inorganic and organic aerosol model (CHIMERE 2017β v1.0): seasonal and spatial evaluation over Europe

NASA Astrophysics Data System (ADS)

Couvidat, Florian; Bessagnet, Bertrand; Garcia-Vivanco, Marta; Real, Elsa; Menut, Laurent; Colette, Augustin

2018-01-01

A new aerosol module was developed and integrated in the air quality model CHIMERE. Developments include the use of the Model of Emissions and Gases and Aerosols from Nature (MEGAN) 2.1 for biogenic emissions, the implementation of the inorganic thermodynamic model ISORROPIA 2.1, revision of wet deposition processes and of the algorithms of condensation/evaporation and coagulation and the implementation of the secondary organic aerosol (SOA) mechanism H2O and the thermodynamic model SOAP. Concentrations of particles over Europe were simulated by the model for the year 2013. Model concentrations were compared to the European Monitoring and Evaluation Programme (EMEP) observations and other observations available in the EBAS database to evaluate the performance of the model. Performances were determined for several components of particles (sea salt, sulfate, ammonium, nitrate, organic aerosol) with a seasonal and regional analysis of results. The model gives satisfactory performance in general. For sea salt, the model succeeds in reproducing the seasonal evolution of concentrations for western and central Europe. For sulfate, except for an overestimation of sulfate in northern Europe, modeled concentrations are close to observations and the model succeeds in reproducing the seasonal evolution of concentrations. For organic aerosol, the model reproduces with satisfactory results concentrations for stations with strong modeled biogenic SOA concentrations. However, the model strongly overestimates ammonium nitrate concentrations during late autumn (possibly due to problems in the temporal evolution of emissions) and strongly underestimates summer organic aerosol concentrations over most of the stations (especially in the northern half of Europe). This underestimation could be due to a lack of anthropogenic SOA or biogenic emissions in northern Europe. A list of recommended tests and developments to improve the model is also given.

Measurement of salivary adiponectin concentrations in dogs.

PubMed

Tvarijonaviciute, Asta; Carrillo-Sanchez, Juana D; García-Martinez, Juan D; Tecles, Fernando; Martinez-Subiela, Silvia; German, Alexander J; Ceron, Jose J

2014-09-01

Measurement of salivary adiponectin could improve understanding of this adipokine's physiology, and its role in various clinical conditions. The purpose of the study was to evaluate the utility of a human adiponectin ELISA kit for measurement of salivary adiponectin in dogs, to compare serum and salivary adiponectin concentrations in a healthy dog population, and to evaluate possible effects of tooth-cleaning on serum and salivary adiponectin concentrations in dogs. For analytical validation, precision, accuracy, and lower limit of quantification of the assay were determined with saliva samples. In addition, adiponectin concentrations were quantified in serum and saliva samples from 24 healthy dogs, and from 7 dogs with mild gingivitis before and after a tooth-cleaning procedure. The validation assays for salivary adiponectin had all coefficients of variation <15%, and recovery ranged from 85% to 120%. In the linearity test, interference was observed when measuring adiponectin in saliva, but this was solved by diluting samples 1:4. In healthy dogs, salivary and serum adiponectin concentrations were positively correlated (r = .650; P = .009). After the tooth-cleaning procedure, salivary adiponectin concentration increased on day 0 (P = .004), but by day 14, concentrations were less than prior to the procedure (P = .041). The human adiponectin ELISA kit can be used for precise and accurate salivary adiponectin measurement in dogs. Salivary adiponectin increased 24 hours after tooth-cleaning, possibly due to acute inflammation or adiponectin leakage from the blood after gingival trauma. © 2014 American Society for Veterinary Clinical Pathology and European Society for Veterinary Clinical Pathology.

Increased response to insulin of glucose metabolism in the 6-day unloaded rat soleus muscle

NASA Technical Reports Server (NTRS)

Henriksen, Erik J.; Tischler, Marc E.; Johnson, David G.

1986-01-01

Hind leg muscles of female rats were unloaded by tail cast suspension for 6 days. In the fresh-frozen unloaded soleus, the significantly greater concentration of glycogen correlated with a lower activity ratio of glycogen phosphorylase (p less than 0.02). The activity ratio of glycogen synthase also was lower (p less than 0.001), possibly due to the higher concentration of glycogen. In isolated unloaded soleus, insulin (0.1 milliunit/ml) increased the oxidation of D(U-C-14) glucose, release of lactate and pyruvate, incorporation of D-(U-C-14) glucose into glycogen, and the concentration of glucose 6-phosphate more (p less than 0.05) than in the weight-bearing soleus. At physiological doses of insulin, the percent of maximal uptake of 2-deoxy-D-(1,2-H-3) glucose/muscle also was greater in the unloaded soleus. Unloading of the soleus increased, by 50 percent the concentration of insuling receptors, due to no decrease in total receptor number during muscle atrophy. This increase may account for the greater response of glucose metabolism to insulin in this muscle. The extensor digitorum longus, which generally shows little response to unloading, displayed no differential response of glucose metabolism to insulin.

Exposure to fine particulate matter and hospital admissions due to pneumonia: Effects on the number of hospital admissions and its costs.

PubMed

Patto, Nicole Vargas; Nascimento, Luiz Fernando Costa; Mantovani, Katia Cristina C; Vieira, Luciana C P F S; Moreira, Demerval S

2016-07-01

Given that respiratory diseases are a major cause of hospitalization in children, the objectives of this study are to estimate the role of exposure to fine particulate matter in hospitalizations due to pneumonia and a possible reduction in the number of these hospitalizations and costs. An ecological time-series study was developed with data on hospitalization for pneumonia among children under 10 years of age living in São José do Rio Preto, state of São Paulo, using PM2.5 concentrations estimated using a mathematical model. We used Poisson regression with a dependent variable (hospitalization) associated with PM2.5 concentrations and adjusted for effective temperature, seasonality and day of the week, with estimates of reductions in the number of hospitalizations and costs. 1,161 children were admitted to hospital between October 1st, 2011, and September 30th, 2013; the average concentration of PM2.5 was 18.7 µg/m3 (≈32 µg/m3 of PM10) and exposure to this pollutant was associated with hospitalization four and five days after exposure. A 10 µg/m3 decrease in concentration would imply 256 less hospital admissions and savings of approximately R$ 220,000 in a medium-sized city.

Concentration and biochemical gradients of seston in Lake Ontario

USGS Publications Warehouse

Kelly, Patrick T.; Weidel, Brian C.; Paufve, Matthew R.; O'Malley, Brian P.; Watkins, James M.; Rudstam, Lars G.; Jones, Stuart E.

2017-01-01

Spatial variability in resource quantity and quality may have important implications for the distribution and productivity of primary consumers. In Lake Ontario, ecosystem characteristics suggest the potential for significant spatial heterogeneity in seston quantity and quality, particularly due to the potential for nearshore-offshore gradients in allochthonous nutrient supply, and the formation of a deep chlorophyll layer (DCL) in July. We assessed total and zooplankton food particle size-fractionated chlorophyll a concentrations, as well as carbon-to-phosphorus stoichiometry and essential fatty acid composition of seston across a distance-from-shore and depth transect. We observed time, sampling depth, and distance from shore to be the best predictors of chlorophyll a concentration. Resource quality was much more homogenous in space, but there were strong patterns through time, as both stoichiometric and fatty acid qualities in general were greatest in May, and lowest in July/August. We did observe a peak in essential fatty acid concentration near the DCL in during time of formation, possibly due to differences in phytoplankton community composition between the DCL and epilimnion. These results suggest the potential for a spatially and temporally dynamic resource base for consumers in Lake Ontario, which may be important in developing a broader understanding of variable consumer productivity.

Growth and Survival of Perchlorate-Reducing Bacteria in Media Containing Elevated Perchlorate Concentrations and UV-C Conditions

NASA Technical Reports Server (NTRS)

Bywaters, K. F.; Mckay, C. P.; Quinn, R. C.

2017-01-01

Introduction: The identification of perchlorate (ClO4(-)) on Mars has led to the possibility that complete redox couples are available for microbial metabolism in contemporary surface environments. Perchlorate-reducing bacteria (PRB) utilize ClO4(-) and chlorate (ClO3(-)) as terminal electron acceptors due to the high reduction potential. Additionally, ClO4(-) salts have been suggested as a possible source of brines on Mars and spectral evidence indicates that the hydration of ClO4(-) salts in the regolith of Martian is linked to the surface recurring slope lineae (RSL). For these reasons PRB may serve as analog organisms for possible life on Mars. However, there is very little information on the viability of PRB in aqueous environments that contain high levels of perchlorate Microorganisms on or near the surface of Mars, such as in the RSL, would potentially be exposed to high-salinity and high ultraviolet radiation environments. Under these extreme conditions, microorganisms must possess mechanisms for maintaining continued high genome fidelity. To assess possible microbial viability in contemporary Mars analog environments we are investigating the tolerance of two PRB strains in aqueous conditions under high UV-C conditions and high ClO4(-) concentrations.

Second-order data obtained by beta-cyclodextrin complexes: a novel approach for multicomponent analysis with three-way multivariate calibration methods.

PubMed

Khani, Rouhollah; Ghasemi, Jahan B; Shemirani, Farzaneh

2014-10-01

This research reports the first application of β-cyclodextrin (β-CD) complexes as a new method for generation of three way data, combined with second-order calibration methods for quantification of a binary mixture of caffeic (CA) and vanillic (VA) acids, as model compounds in fruit juices samples. At first, the basic experimental parameters affecting the formation of inclusion complexes between target analytes and β-CD were investigated and optimized. Then under the optimum conditions, parallel factor analysis (PARAFAC) and bilinear least squares/residual bilinearization (BLLS/RBL) were applied for deconvolution of trilinear data to get spectral and concentration profiles of CA and VA as a function of β-CD concentrations. Due to severe concentration profile overlapping between CA and VA in β-CD concentration dimension, PARAFAC could not be successfully applied to the studied samples. So, BLLS/RBL performed better than PARAFAC. The resolution of the model compounds was possible due to differences in the spectral absorbance changes of the β-CD complexes signals of the investigated analytes, opening a new approach for second-order data generation. The proposed method was validated by comparison with a reference method based on high-performance liquid chromatography photodiode array detection (HPLC-PDA), and no significant differences were found between the reference values and the ones obtained with the proposed method. Such a chemometrics-based protocol may be a very promising tool for more analytical applications in real samples monitoring, due to its advantages of simplicity, rapidity, accuracy, sufficient spectral resolution and concentration prediction even in the presence of unknown interferents. Copyright © 2014 Elsevier B.V. All rights reserved.

Airborne castanea pollen forecasting model for ecological and allergological implementation.

PubMed

Astray, G; Fernández-González, M; Rodríguez-Rajo, F J; López, D; Mejuto, J C

2016-04-01

Castanea sativa Miller belongs to the natural vegetation of many European deciduous forests prompting impacts in the forestry, ecology, allergological and chestnut food industry fields. The study of the Castanea flowering represents an important tool for evaluating the ecological conservation of North-Western Spain woodland and the possible changes in the chestnut distribution due to recent climatic change. The Castanea pollen production and dispersal capacity may cause hypersensitivity reactions in the sensitive human population due to the relationship between patients with chestnut pollen allergy and a potential cross reactivity risk with other pollens or plant foods. In addition to Castanea pollen's importance as a pollinosis agent, its study is also essential in North-Western Spain due to the economic impact of the industry around the chestnut tree cultivation and its beekeeping interest. The aim of this research is to develop an Artificial Neural Networks for predict the Castanea pollen concentration in the atmosphere of the North-West Spain area by means a 20years data set. It was detected an increasing trend of the total annual Castanea pollen concentrations in the atmosphere during the study period. The Artificial Neural Networks (ANNs) implemented in this study show a great ability to predict Castanea pollen concentration one, two and three days ahead. The model to predict the Castanea pollen concentration one day ahead shows a high linear correlation coefficient of 0.784 (individual ANN) and 0.738 (multiple ANN). The results obtained improved those obtained by the classical methodology used to predict the airborne pollen concentrations such as time series analysis or other models based on the correlation of pollen levels with meteorological variables. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling reactive ammonia uptake by secondary organic aerosol in CMAQ: application to the continental US

NASA Astrophysics Data System (ADS)

Zhu, Shupeng; Horne, Jeremy R.; Montoya-Aguilera, Julia; Hinks, Mallory L.; Nizkorodov, Sergey A.; Dabdub, Donald

2018-03-01

Ammonium salts such as ammonium nitrate and ammonium sulfate constitute an important fraction of the total fine particulate matter (PM2.5) mass. While the conversion of inorganic gases into particulate-phase sulfate, nitrate, and ammonium is now well understood, there is considerable uncertainty over interactions between gas-phase ammonia and secondary organic aerosols (SOAs). Observations have confirmed that ammonia can react with carbonyl compounds in SOA, forming nitrogen-containing organic compounds (NOCs). This chemistry consumes gas-phase NH3 and may therefore affect the amount of ammonium nitrate and ammonium sulfate in particulate matter (PM) as well as particle acidity. In order to investigate the importance of such reactions, a first-order loss rate for ammonia onto SOA was implemented into the Community Multiscale Air Quality (CMAQ) model based on the ammonia uptake coefficients reported in the literature. Simulations over the continental US were performed for the winter and summer of 2011 with a range of uptake coefficients (10-3-10-5). Simulation results indicate that a significant reduction in gas-phase ammonia may be possible due to its uptake onto SOA; domain-averaged ammonia concentrations decrease by 31.3 % in the winter and 67.0 % in the summer with the highest uptake coefficient (10-3). As a result, the concentration of particulate matter is also significantly affected, with a distinct spatial pattern over different seasons. PM concentrations decreased during the winter, largely due to the reduction in ammonium nitrate concentrations. On the other hand, PM concentrations increased during the summer due to increased biogenic SOA (BIOSOA) production resulting from enhanced acid-catalyzed uptake of isoprene-derived epoxides. Since ammonia emissions are expected to increase in the future, it is important to include NH3 + SOA chemistry in air quality models.

Irreversible sorption of trace concentrations of perfluorocarboxylic acids to fiber filters used for air sampling

NASA Astrophysics Data System (ADS)

Arp, Hans Peter H.; Goss, Kai-Uwe

Due to the apparent environmental omnipresence of perfluorocarboxylic acids (PFAs), an increasing number of researchers are investigating their ambient particle- and gas-phase concentrations. Typically this is done using a high-volume air sampler equipped with Quartz Fiber Filters (QFFs) or Glass Fiber Filters (GFFs) to sample the particle-bound PFAs and downstream sorbents to sample the gas-phase PFAs. This study reports that at trace, ambient concentrations gas-phase PFAs sorb to QFFs and GFFs irreversibly and hardly pass through these filters to the downstream sorbents. As a consequence, it is not possible to distinguish between particle- and gas-phase concentrations, or to distinguish concentrations on different particle size fractions, unless precautions are taken. Failure to take such precautions could have already caused reported data to be misinterpreted. Here it is also reported that deactivating QFFs and GFFs with a silylating agent renders them suitable for sampling PFAs. Based on the presented study, a series of recommendations for air-sampling PFAs are provided.

Vertical profile measurements of soil air suggest immobilization of gaseous elemental mercury in mineral soil.

PubMed

Obrist, Daniel; Pokharel, Ashok K; Moore, Christopher

2014-02-18

Evasion of gaseous elemental Hg (Hg(0)g) from soil surfaces is an important source of atmospheric Hg, but the volatility and solid-gas phase partitioning of Hg(0) within soils is poorly understood. We developed a novel system to continuously measure Hg(0)g concentrations in soil pores at multiple depths and locations, and present a total of 297 days of measurements spanning 14 months in two forests in the Sierra Nevada mountains, California, U.S. Temporal patterns showed consistent pore Hg(0)g concentrations below levels measured in the atmosphere (termed Hg(0)g immobilization), ranging from 66 to 94% below atmospheric concentrations throughout multiple seasons. The lowest pore Hg(0)g concentrations were observed in the deepest soil layers (40 cm), but significant immobilization was already present in the top 7 cm. In the absence of sinks or sources, pore Hg(0)g levels would be in equilibrium with atmospheric concentrations due to the porous nature of the soil matrix and gas diffusion. Therefore, we explain decreases in pore Hg(0)g in mineral soils below atmospheric concentrations--or below levels found in upper soils as observed in previous studies--with the presence of an Hg(0)g sink in mineral soils possibly related to Hg(0)g oxidation or other processes such as sorption or dissolution in soil water. Surface chamber measurements showing daytime Hg(0)g emissions and nighttime Hg(0)g deposition indicate that near-surface layers likely dominate net atmospheric Hg(0)g exchange resulting in typical diurnal cycles due to photochemcial reduction at the surface and possibly Hg(0)g evasion from litter layers. In contrast, mineral soils seem to be decoupled from this surface exchange, showing consistent Hg(0)g uptake and downward redistribution--although our calculations indicate these fluxes to be minor compared to other mass fluxes. A major implication is that once Hg is incorporated into mineral soils, it may be unlikely subjected to renewed Hg(0)g re-emission from undisturbed, background soils emphasizing the important role of soils in sequestering past and current Hg pollution loads.

Antiretroviral pharmacokinetics in mothers and breastfeeding infants from 6 to 24 weeks post partum: results of the BAN Study

PubMed Central

Corbett, Amanda H; Kayira, Dumbani; White, Nicole R; Davis, Nicole L; Kourtis, Athena P; Chasela, Charles; Martinson, Francis; Phiri, Grace; Musisi, Bonaface; Kamwendo, Deborah; Hudgens, Michael G; Hosseinipour, Mina C; Nelson, Julie AE; Ellington, Sascha R; Jamieson, Denise J; van der Horst, Charles; Kashuba, Angela

2014-01-01

Background An intensive, prospective, open-label pharmacokinetic (PK) study in a subset of HIV-infected mothers and their uninfected infants enrolled in the Breastfeeding, Antiretroviral, and Nutrition study was performed to describe drug exposure and antiviral response. Methods Women using Combivir®[zidovudine (ZDV)+ lamivudine (3TC)]+Aluvia®[lopinavir/ritonavir(LPV/RTV)] were enrolled. Breast milk (BM) and mother and infant plasma (MP, IP) samples were obtained over 6hrs after observed dosing at 6, 12, or 24wks post-partum for drug concentrations and HIV RNA. Results 30 mother/infant pairs (10 each at 6, 12,and 24wks post-partum) were enrolled. Relative to MP, BM concentrations of ZDV and 3TC were 35% and 21% higher, while LPV and RTV were 80% lower. Only 3TC was detected in IP with concentrations 96% and 98% lower than MP and BM, respectively. Concentrations in all matrices were similar at 6-24wks. The majority (98.3%) of BM concentrations were >HIVwt IC50, with one having detectable virus. There was no association between PK parameters and MP or BM HIV RNA. Conclusions ZDV and 3TC concentrated in BM while LPV and RTV did not, possibly due to protein binding and drug transporter affinity. Undetectable to low ARV concentrations in IP suggests prevention of transmission while breast feeding may be due to ARV effects on systemic or BM HIV RNA in the mother. Low IP 3TC exposure may predispose an infected infant to HIV resistance, necessitating testing and treating infants early. PMID:24464632

Long-Term Monitoring of PAH Contamination in Sediment and Recovery After the Hebei Spirit Oil Spill.

PubMed

Kim, Moonkoo; Jung, Jee-Hyun; Ha, Sung Yong; An, Joon Geon; Shim, Won Joon; Yim, Un Hyuk

2017-07-01

Approximately 10,900 t of crude oil was released 10 km off the west coast of Korea after the collision between the oil tanker Hebei Spirit and a barge carrying a crane in December 2007. To assess the areal extent and temporal trends of PAH contamination, 428 sediment samples were collected from December 2007 through May 2015 for PAH analysis. Sedimentary PAH concentrations measured immediately after the spill ranged from 3.2 to 71,200 ng g -1 , with a mean of 3800 ng g -1 . Increases in PAH concentrations were observed at stations 7-23, which were heavily oiled due to tidal currents and northwesterly wind that transported the spilled oil to these locations. Mean and maximum PAH concentrations decreased drastically from 3800 to 88.5 and 71,200 to 1700 ng g -1 , respectively, 4 months after the spill. PAH concentrations highly fluctuated until September 2008 and then decreased slowly to background levels. Reduction rate was much faster at the sandy beaches (k = 0.016) than in the muddy sites (k = 0.001). In muddy sediments, low attenuation due to low flushing rate in the mostly anaerobic sediment possibly contributed the persistence of PAHs. By May 2015 (~7.5 years after the spill), mean and maximum PAH concentrations decreased by 54 and 481 times, respectively, compared with the peak concentrations. The sedimentary PAH concentrations in the monitoring area have returned to regional background levels.

How the reference values for serum parathyroid hormone concentration are (or should be) established?

PubMed

Souberbielle, J-C; Brazier, F; Piketty, M-L; Cormier, C; Minisola, S; Cavalier, E

2017-03-01

Well-validated reference values are necessary for a correct interpretation of a serum PTH concentration. Establishing PTH reference values needs recruiting a large reference population. Exclusion criteria for this population can be defined as any situation possibly inducing an increase or a decrease in PTH concentration. As recommended in the recent guidelines on the diagnosis and management of asymptomatic primary hyperparathyroidism, PTH reference values should be established in vitamin D-replete subjects with a normal renal function with possible stratification according to various factors such as age, gender, menopausal status, body mass index, and race. A consensus about analytical/pre-analytical aspects of PTH measurement is also needed with special emphasis on the nature of the sample (plasma or serum), the time and the fasting/non-fasting status of the blood sample. Our opinion is that blood sample for PTH measurement should be obtained in the morning after an overnight fast. Furthermore, despite longer stability of the PTH molecule in EDTA plasma, we prefer serum as it allows to measure calcium, a prerequisite for a correct interpretation of a PTH concentration, on the same sample. Once a consensus is reached, we believe an important international multicentre work should be performed to recruit a very extensive reference population of apparently healthy vitamin D-replete subjects with a normal renal function in order to establish the PTH normative data. Due to the huge inter-method variability in PTH measurement, a sufficient quantity of blood sample should be obtained to allow measurement with as many PTH kits as possible.

Relation of a seafood diet to mercury, selenium, arsenic, and polychlorinated biphenyl and other organochlorine concentrations in human milk.

PubMed

Grandjean, P; Weihe, P; Needham, L L; Burse, V W; Patterson, D G; Sampson, E J; Jørgensen, P J; Vahter, M

1995-10-01

Human transition milk was sampled from 88 mothers at the Faroe Islands, where the seafood diet includes pilot whale meat and blubber. Milk mercury concentrations (median, 2.45 micrograms/liter) were significantly associated with mercury concentrations in cord blood and with the frequency of pilot whale dinners during pregnancy. Milk selenium concentrations (mean, 19.1 micrograms/liter) correlated significantly with concentrations in cord blood but not with seafood consumption. Arsenic concentrations were very low. Twenty-four of the milk samples were separated into four pools based on fish intake and milk mercury concentrations. The polychlorinated biphenyl (PCB) concentrations (1.8-3.5 micrograms/g lipid) were high and mainly due to congener numbers 153, 180, and 138. One pool contained a congener 77 concentration of 1380 ppt, which is the highest ever reported in a human specimen for a coplanar PCB. The highest PCB concentrations were seen in the pools from women who had eaten frequent whale dinners and whose milk contained high mercury concentrations. The concentrations of chlorinated dibenzo-p-dioxins and furans were not similarly elevated. Given the advantages associated with breast-feeding, advice to nursing mothers in this population should take into regard the possible risks associated with long-term exposure to milk contaminants.

Fine particle number and mass concentration measurements in urban Indian households.

PubMed

Mönkkönen, P; Pai, P; Maynard, A; Lehtinen, K E J; Hämeri, K; Rechkemmer, P; Ramachandran, G; Prasad, B; Kulmala, M

2005-07-15

Fine particle number concentration (D(p)>10 nm, cm(-3)), mass concentrations (approximation of PM(2.5), microg m(-3)) and indoor/outdoor number concentration ratio (I/O) measurements have been conducted for the first time in 11 urban households in India, 2002. The results indicate remarkable high indoor number and mass concentrations and I/O number concentration ratios caused by cooking. Besides cooking stoves that used liquefied petroleum gas (LPG) or kerosene as the main fuel, high indoor concentrations can be explained by poor ventilation systems. Particle number concentrations of more than 300,000 cm(-3) and mass concentrations of more than 1000 microg m(-3) were detected in some cases. When the number and mass concentrations during cooking times were statistically compared, a correlation coefficient r>0.50 was observed in 63% of the households. Some households used other fuels like wood and dung cakes along with the main fuel, but also other living activities influenced the concentrations. In some areas, outdoor combustion processes had a negative impact on indoor air quality. The maximum concentrations observed in most cases were due to indoor combustion sources. Reduction of exposure risk and health effects caused by poor indoor air in urban Indian households is possible by improving indoor ventilation and reducing penetration of outdoor particles.

HRE-type genes are regulated by growth-related changes in internal oxygen concentrations during the normal development of potato (Solanum tuberosum) tubers.

PubMed

Licausi, Francesco; Giorgi, Federico Manuel; Schmälzlin, Elmar; Usadel, Björn; Perata, Pierdomenico; van Dongen, Joost Thomas; Geigenberger, Peter

2011-11-01

The occurrence of hypoxic conditions in plants not only represents a stress condition but is also associated with the normal development and growth of many organs, leading to adaptive changes in metabolism and growth to prevent internal anoxia. Internal oxygen concentrations decrease inside growing potato tubers, due to their active metabolism and increased resistance to gas diffusion as tubers grow. In the present work, we identified three hypoxia-responsive ERF (StHRE) genes whose expression is regulated by the gradual decrease in oxygen tensions that occur when potato tubers grow larger. Increasing the external oxygen concentration counteracted the modification of StHRE expression during tuber growth, supporting the idea that the actual oxygen levels inside the organs, rather than development itself, are responsible for the regulation of StHRE genes. We identified several sugar metabolism-related genes co-regulated with StHRE genes during tuber development and possibly involved in starch accumulation. All together, our data suggest a possible role for low oxygen in the regulation of sugar metabolism in the potato tuber, similar to what happens in storage tissues during seed development.

Assessment of microcystin distribution and biomagnification in tissues of aquatic food web compartments from a shallow lake and evaluation of potential risks to public health.

PubMed

Papadimitriou, Theodoti; Kagalou, Ifigenia; Stalikas, Constantinos; Pilidis, Georgios; Leonardos, Ioannis D

2012-05-01

The objectives of this study were: (1) to examine the distribution and bioaccumulation of microcystins in the main components of the food web (phytoplankton, zooplankton, crayfish, shrimp, mussel, snail, fish, frog) of Lake Pamvotis (NW Greece), (2) to investigate the possibility of microcystin biomagnification and (3) to evaluate the potential threat of the contaminated aquatic organisms to human health. Significant microcystin concentrations were detected in all the aquatic organisms during two different periods, with the higher concentrations observed in phytoplankton and the lower in fish species and frogs. This is the first study reporting microcystin accumulation in the body of the freshwater shrimp Atyaephyra desmsaresti, in the brain of the fish species common carp (Cyprinus carpio) and in the skin of the frog Rana epirotica. Although there was no evidence for microcystin biomagnification, the fact that microcystins were found in lake water and in the tissues of aquatic organisms, suggests that serious risks to animal and public health are possible to occur. In addition, it is likely to be unsafe to consume aquatic species harvested in Lake Pamvotis due to the high-concentrations of accumulated microcystins.

Quantitative reconstruction of refractive index distribution and imaging of glucose concentration by using diffusing light.

PubMed

Liang, Xiaoping; Zhang, Qizhi; Jiang, Huabei

2006-11-10

We show that a two-step reconstruction method can be adapted to improve the quantitative accuracy of the refractive index reconstruction in phase-contrast diffuse optical tomography (PCDOT). We also describe the possibility of imaging tissue glucose concentration with PCDOT. In this two-step method, we first use our existing finite-element reconstruction algorithm to recover the position and shape of a target. We then use the position and size of the target as a priori information to reconstruct a single value of the refractive index within the target and background regions using a region reconstruction method. Due to the extremely low contrast available in the refractive index reconstruction, we incorporate a data normalization scheme into the two-step reconstruction to combat the associated low signal-to-noise ratio. Through a series of phantom experiments we find that this two-step reconstruction method can considerably improve the quantitative accuracy of the refractive index reconstruction. The results show that the relative error of the reconstructed refractive index is reduced from 20% to within 1.5%. We also demonstrate the possibility of PCDOT for recovering glucose concentration using these phantom experiments.

Effects of ozonation pretreatment on natural organic matter and wastewater derived organic matter - Possible implications on the formation of ozonation by-products.

PubMed

Papageorgiou, Alexandros; Stylianou, Stylianos K; Kaffes, Pavlos; Zouboulis, Anastasios I; Voutsa, Dimitra

2017-03-01

The aim of this study was to investigate possible implications of natural and wastewater derived organic matter in river water that is subsequently used following treatment for drinking purposes. River water was subjected to lab-scale ozonation experiments under different ozone doses (0.1, 0.4, 0.8, 1.0 and 2.0 mgO 3 /mgC) and contact times (1, 3, 5, 8 and 10 min). Mixtures of river water with humic acids or wastewaters (sewage wastewater and secondary effluents) at different proportions were also ozonated. Dissolved organic carbon and biodegradable dissolved organic carbon concentrations as well as spectroscopic characteristics (UV absorbance and fluorescence intensities) of different types of dissolved organic matter and possible changes due to the ozonation treatment are presented. River water, humic substances and wastewater exhibited distinct spectroscopic characteristics that could serve for pollution source tracing. Wastewater impacted surface water results in higher formation of carbonyl compounds. However, the formation yield (μg/mgC) of wastewaters was lower than that of surface water possibly due to different composition of wastewater derived organic matter and the presence of scavengers, which may limit the oxidative efficiency of ozone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metal assisted photochemical etching of 4H silicon carbide

NASA Astrophysics Data System (ADS)

Leitgeb, Markus; Zellner, Christopher; Schneider, Michael; Schwab, Stefan; Hutter, Herbert; Schmid, Ulrich

2017-11-01

Metal assisted photochemical etching (MAPCE) of 4H-silicon carbide (SiC) in Na2S2O8/HF and H2O2/HF aqueous solutions is investigated with platinum as metallic cathode. The formation process of the resulting porous layer is studied with respect to etching time, concentration and type of oxidizing agent. From the experiments it is concluded that the porous layer formation is due to electron hole pairs generated in the semiconductor, which stem from UV light irradiation. The generated holes are consumed during the oxidation of 4H-SiC and the formed oxide is dissolved by HF. To maintain charge balance, the oxidizing agent has to take up electrons at the Pt/etching solution interface. Total dissolution of the porous layers is achieved when the oxidizing agent concentration decreases during MAPCE. In combination with standard photolithography, the definition of porous regions is possible. Furthermore chemical micromachining of 4 H-SiC at room temperature is possible.

Toxicity of tributyltin in the marine mollusc Mytilus edulis.

PubMed

Hagger, Josephine A; Depledge, Michael H; Galloway, Tamara S

2005-01-01

Our previous studies have demonstrated that tributyltin (TBT) is genotoxic to the early life stages of marine mussels and worms. Here, the toxicity of TBT to adult organisms was determined using a suite of biomarkers designed to detect cytotoxic, immunotoxic and genotoxic effects. Exposure of adult mussels, Mytilus edulis, to environmentally realistic concentrations of TBTO for 7 days resulted in a statistically significant decrease in cell viability at concentrations of 0.5 microg/l and above. TBT had no effect on phagocytic activity or antioxidant capacity (FRAP assay). There was a statistically significant increase in DNA damage detected using the comet and micronucleus assays between the controls and 0.5, 1 and 5 microg/l of TBTO (P > 0.0005). Furthermore there was a strong correlation between DNA strand breaks (comet assay) and formation of micronuclei (P = 0.0005; R2 = 61.5%). Possible mechanisms by which TBT could damage DNA either directly or indirectly are discussed including the possibility that TBT is genotoxic due to its ability to disrupt calcium homeostasis.

Glucose concentration measured by the hybrid coherent anti-Stokes Raman-scattering technique

NASA Astrophysics Data System (ADS)

Wang, Xi; Zhang, Aihua; Zhi, Miaochan; Sokolov, Alexei V.; Welch, George R.

2010-01-01

We investigate the possibility of using a hybrid coherent anti-Stokes Raman scattering technique for noninvasive monitoring of blood glucose levels. Our technique combines instantaneous coherent excitation of several characteristic molecular vibrations with subsequent probing of these vibrations by an optimally shaped, time-delayed, narrowband laser pulse. This pulse configuration mitigates the nonresonant four-wave mixing background while maximizing the Raman-resonant signal and allows rapid and highly specific detection even in the presence of multiple scattering. Under certain conditions we find that the measured signal is linearly proportional to the glucose concentration due to optical interference with the residual background light, which allows reliable detection of spectral signatures down to medically relevant glucose levels.

A Comparative Study Environmental and Radiological Causes Of Cancer In River Nile State, Sudan

NASA Astrophysics Data System (ADS)

Hamid, Eyad; Khair, Hatim

The causes of cancer in River Nile state are differ between environmental and radiological, this paper tried to make comparison between the two causes, to determine the real cause behind the large rising of cancer cases in this state, considering the daily habits for the patients and the possible contamination in the natural resources around them. The noticeable thing that most of cancer cases are might be due to the high concentration of nitrate pollutant detected in natural resources such as drinking water; also by looking to the radioactive elements we see there's high concentration of some radioactive elements specially the K-40 which found in Portulaca Oleracea.

MHD conversion of solar energy. [space electric power system

NASA Technical Reports Server (NTRS)

Lau, C. V.; Decher, R.

1978-01-01

Low temperature plasmas wherein an alkali metal vapor is a component are uniquely suited to simultaneously absorb solar radiation by coupling to the resonance lines and produce electrical power by the MHD interaction. This work is an examination of the possibility of developing space power systems which take advantage of concentrated solar power to produce electricity. It is shown that efficient cycles in which expansion work takes place at nearly constant top cycle temperature can be devised. The power density of the solar MHD generator is lower than that of conventional MHD generators because of the relatively high seed concentration required for radiation absorption and the lower flow velocity permitted to avoid total pressure losses due to heating.

Mathematical model of device for slurry concentration and desludging in near-bottom zone

NASA Astrophysics Data System (ADS)

Shishkin, P. V.; Trufanova, I. S.

2017-10-01

There are many systems for extracting minerals from the bottom of water bodies, but none of them meets the requirements, so the actual task is to create technical means that provide the best performance and environmental safety. Increase the efficiency of the hydromechanical mining method is possible due to the maximum concentration and desludging of the slurry in the near-bottom zone, which allows reducing the energy and material consumption of hydrotransport of minerals. To achieve this goal, it is proposed to use a perforated section adjacent to the power unit, with a transverse cross section that reduces in its length in the direction of flow, in the pressure pulp pipeline system.

Oxidative tryptophan modification by terpene- and squalene-hydroperoxides and a possible link to cross-reactions in diagnostic tests.

PubMed

Natsch, Andreas; Emter, Roger; Badertscher, Remo P; Brunner, Gerhard; Granier, Thierry; Kern, Susanne; Ellis, Graham

2015-06-15

Hydroperoxides can act as specific haptens and oxidatively modify proteins. Terpene hydroperoxides trigger unusually high frequencies of positive skin reactions in human patients if tested at high concentrations. It is unknown whether this is due to specific hapten formation. Here, we show that both terpene hydroperoxides and the endogenous hydroperoxide formed from squalene can oxidatively modify tryptophan. Oxidative modifications of Trp were recently postulated to explain cross-sensitization between unrelated photosensitizers. Current observations may extend this hypothesis: Oxidative events triggered by endogenous hydroperoxides and hydroperoxides/oxidants derived from xenobiotics might lead to a sensitized state detected by patch tests with high concentrations of hydroperoxides.

Effect of graphite oxide solution concentration on the properties of multilayer graphene

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

Umar, Marjoni Imamora Ali; Yap, Chi Chin; Awang, Rozidawati

2013-11-27

This paper reports the influence of graphite oxide (GO) solution concentration on the optical and electrical properties of multilayer graphene (MLG) films. Graphene oxide (GrO) films were deposited on the glass substrates by spin coating aqueous solutions of GO with different concentrations (7, 8, 9, 10 and 11 mg/ml). The GrO films were then thermally reduced at temperature of 500°C in argon flow for half an hour to form MLG films. Both the transmittance and sheet resistance decreased with the GO concentration from 8 mg/ml to 9 mg/ml, possibly due to thicker and uniform coverage of MLG over the substrate.more » However, the transmittance and sheet resistance increased rapidly as the GO concentration reached 11 mg/ml, which can be attributed to poor film quality. The MLG film obtained at concentration of 10 mg/ml showed the highest transmittance/sheet resistance ratio with 69 % transmittance and sheet resistance of 292 ± 63 kΩ/sq. The optimum MLG film was utilized as counter electrode in dye sensitized solar cells based on ZnO nanorods.« less

The relationship between the nitrate concentration and hydrology of a small chalk spring; Israel

NASA Astrophysics Data System (ADS)

Burg, Avi; Heaton, Tim H. E.

1998-01-01

Discharge from a spring draining a small, perched, Cretaceous chalk aquifer in the Upper Galilee, Israel, was monitored over a period of two years. The water has elevated nitrate concentrations, with 15N/ 14N and chemical data suggesting that it is a mixture of low-nitrate and high-nitrate end-members; the latter derived from the sewage of a centuries-old village served by septic tanks. Hydrograph data allowed distinction between fissure flow during the period of winter rainfall, and matrix drainage during the dry summer months. These different flow types, however, did not have markedly different nitrate concentrations: a 50-fold increase in spring discharge due to fissure flow, compared with matrix drainage, was reflected in only a 35% decrease in nitrate concentrations. The relatively high nitrate concentrations in the fissure waters suggests that they have had close contact with, and are possibly displaced from the matrix. This should help to accelerate the decline in the spring's nitrate concentrations following the recent completion of the village's central sewage drainage system.

Response of Lemna minor L. to short-term cobalt exposure: The effect on photosynthetic electron transport chain and induction of oxidative damage.

PubMed

Begović, Lidija; Mlinarić, Selma; Antunović Dunić, Jasenka; Katanić, Zorana; Lončarić, Zdenko; Lepeduš, Hrvoje; Cesar, Vera

2016-06-01

The effect of two concentrations of cobalt (Co(2+)) on photosynthetic activity and antioxidative response in Lemna minor L. were assessed 24, 48 and 72h after the start of the exposure. Higher concentration of cobalt (1mM) induced growth inhibition while lower concentration (0.01mM) increased photosynthetic pigments content. Analysis of chlorophyll a fluorescence transients revealed high sensitivity of photosystem II primary photochemistry to excess of Co(2+) especially at the higher concentration where decreased electron transport beyond primary quinone acceptor QA(-) and impaired function of oxygen evolving complex (OEC) was observed. Due to impairment of OEC, oxygen production was decreased at higher Co(2+) concentration. Activity of superoxide dismutase was mainly inhibited while lipid peroxidation increased, at both concentrations, indicating that cobalt-induced oxidative damage after short exposure and moreover, susceptibility of the membranes in the cell to cobalt toxicity. Results obtained in this study suggest possible application of used parameters as tools in assessment of early damage caused by metals. Copyright © 2016 Elsevier B.V. All rights reserved.

Mathematical simulations for bioanalytical assay development: the (un-)necessity and (im-)possibility of free drug quantification.

PubMed

Staack, Roland F; Jordan, Gregor; Heinrich, Julia

2012-02-01

For every drug development program it needs to be discussed whether discrimination between free and total drug concentrations is required to accurately describe its pharmacokinetic behavior. This perspective describes the application of mathematical simulation approaches to guide this initial decision based on available knowledge about target biology, binding kinetics and expected drug concentrations. We provide generic calculations that can be used to estimate the necessity of free drug quantification for different drug molecules. In addition, mathematical approaches are used to simulate various assay conditions in bioanalytical ligand-binding assays: it is demonstrated that due to the noncovalent interaction between the binding partners and typical assay-related interferences in the equilibrium, a correct quantification of the free drug concentration is highly challenging and requires careful design of different assay procedure steps.

Acoustically levitated droplets: a contactless sampling method for fluorescence studies.

PubMed

Leiterer, Jork; Grabolle, Markus; Rurack, Knut; Resch-Genger, Ute; Ziegler, Jan; Nann, Thomas; Panne, Ulrich

2008-01-01

Acoustic levitation is used as a new tool to study concentration-dependent processes in fluorescence spectroscopy. With this technique, small amounts of liquid and solid samples can be measured without the need for sample supports or containers, which often limits signal acquisition and can even alter sample properties due to interactions with the support material. We demonstrate that, because of the small sample volume, fluorescence measurements at high concentrations of an organic dye are possible without the limitation of inner-filter effects, which hamper such experiments in conventional, cuvette-based measurements. Furthermore, we show that acoustic levitation of liquid samples provides an experimentally simple way to study distance-dependent fluorescence modulations in semiconductor nanocrystals. The evaporation of the solvent during levitation leads to a continuous increase of solute concentration and can easily be monitored by laser-induced fluorescence.

Interpreting Tacrolimus Concentrations During Pregnancy and Postpartum

PubMed Central

Hebert, Mary F.; Zheng, Songmao; Hays, Karen; Shen, Danny D.; Davis, Connie L.; Umans, Jason G.; Miodovnik, Menachem; Thummel, Kenneth E.; Easterling, Thomas R.

2012-01-01

Summary Pregnancy following solid organ transplantation, although considered high risk for maternal, fetal and neonatal complications, has been quite successful. Tacrolimus pharmacokinetic changes during pregnancy make interpretation of whole blood trough concentrations particularly challenging. There are multiple factors that can increase the fraction of unbound tacrolimus, including but not limited to low albumin concentration and low RBC count. The clinical titration of dosage to maintain whole blood tacrolimus trough concentrations in the usual therapeutic range can lead to elevated unbound concentrations and possibly toxicity in pregnant women with anemia and hypoalbuminemia. Measurement of plasma or unbound tacrolimus concentrations for pregnant women might better reflect the active form of the drug, though these are technically-challenging and often unavailable in usual clinical practice. Tacrolimus crosses the placenta with in utero exposure being approximately 71% of maternal blood concentrations. The lower fetal blood concentrations are likely due to active efflux transport of tacrolimus from the fetus toward the mother by placental P-glycoprotein. To date, tacrolimus has not been linked to congenital malformations, but can cause reversible nephrotoxicity and hyperkalemia in the newborn. In contrast, very small amounts of tacrolimus are excreted in the breast milk and are unlikely to elicit adverse effects in the nursing infant. PMID:23274970

The use of minimum selectable concentrations (MSCs) for determining the selection of antimicrobial resistant bacteria.

PubMed

Khan, Sadia; Beattie, Tara K; Knapp, Charles W

2017-03-01

The use of antimicrobial compounds is indispensable in many industries, especially drinking water production, to eradicate microorganisms. However, bacterial growth is not unusual in the presence of disinfectant concentrations that would be typically lethal, as bacterial populations can develop resistance. The common metric of population resistance has been based on the Minimum Inhibitory Concentration (MIC), which is based on bacteria lethality. However, sub-lethal concentrations may also select for resistant bacteria due to the differences in bacterial growth rates. This study determined the Minimal Selective Concentrations (MSCs) of bacterial populations exposed to free chlorine and monochloramine, representing a metric that possibly better reflects the selective pressures occurring at lower disinfectant levels than MIC. Pairs of phylogenetically similar bacteria were challenged to a range of concentrations of disinfectants. The MSCs of free chlorine and monochloramine were found to range between 0.021 and 0.39 mg L -1 , which were concentrations 1/250 to 1/5 than the MICs of susceptible bacteria (MIC susc ). This study indicates that sub-lethal concentrations of disinfectants could result in the selection of resistant bacterial populations, and MSCs would be a more sensitive indicator of selective pressure, especially in environmental systems.

Thermodynamic and Kinetic Requirements in Anaerobic Methane Oxidizing Consortia Exclude Hydrogen, Acetate, and Methanol as Possible Electron Shuttles.

PubMed

Sørensen, K.B.; Finster, K.; Ramsing, N.B.

2001-07-01

Anaerobic methane oxidation (AMO) has long remained an enigma in microbial ecology. In the process the net reaction appears to be an oxidation of methane with sulfate as electron acceptor. In order to explain experimental data such as effects of inhibitors and isotopic signals in biomarkers it has been suggested that the process is carried out by a consortium of bacteria using an unknown compound to shuttle electrons between the participants. The overall change in free energy during AMO with sulfate is very small (?22 kJ mol-1) at in situ concentrations of methane and sulfate. In order to share the available free energy between the members of the consortium, the concentration of the intermediate electron shuttle compound becomes crucial. Diffusive flux of a substrate (i.e, the electron shuttle) between bacteria requires a stable concentration gradient where the concentration is higher in the producing organism than in the consuming organism. Since changes in concentrations cause changes in reaction free energies, the diffusive flux of a catabolic product/substrate between bacteria is associated with a net loss of available energy. This restricts maximal inter-bacterial distances in consortia composed of stationary bacteria. A simple theoretical model was used to describe the relationship between inter-bacterial distances and the energy lost due to concentration differences in consortia. Key parameters turned out to be the permissible concentration range of the electron shuttle in the consortium (i.e., the concentration range that allows both participants to gain sufficient energy) and the stoichiometry of the partial reactions. The model was applied to two known consortia degrading ethanol and butyrate and to four hypothetical methane-oxidizing consortia (MOC) based on interspecies transfer of hydrogen, methanol, acetate, or formate, respectively. In the first three MOCs the permissible distances between producers and consumers of the transferred compounds were less than two times prokaryotic cell wall diameters. Consequently, it is not possible that a MOC can be based on inter-species transfer of hydrogen, methanol, or acetate. Formate, on the other hand, is a possible shuttle candidate provided the bacteria are attached to one another. In general the model predicts that members of consortia thriving on low energy such as the MOC must adhere to each other and utilize a compound for the exchange of electrons that has a high permissible concentration range and a high diffusion coefficient and transfers as many electrons as possible per molecule.

Kinetic Roughening Transition and Energetics of Tetragonal Lysozyme Crystal Growth

NASA Technical Reports Server (NTRS)

Gorti, Sridhar; Forsythe, Elizabeth L.; Pusey, Marc L.

2004-01-01

Interpretation of lysozyme crystal growth rates using well-established physical theories enabled the discovery of a phenomenon possibly indicative of kinetic roughening. For example, lysozyme crystals grown above a critical supersaturation sigma, (where supersaturation sigma = ln c/c(sub eq), c = the protein concentration and c(sub eq) = the solubility concentration) exhibit microscopically rough surfaces due to the continuous addition of growth units anywhere on the surface of a crystal. The rate of crystal growth, V(sub c), for the continuous growth process is determined by the continuous flux of macromolecules onto a unit area of the crystal surface, a, from a distance, xi, per unit time due to diffusion, and a probability of attachment onto the crystal surface, expressed. Based upon models applied, the energetics of lysozyme crystal growth was determined. The magnitudes of the energy barriers of crystal growth for both the (110) and (101) faces of tetragonal lysozyme crystals are compared. Finally, evidence supportive of the kinetic roughening hypothesis is presented.

Synthesis and evaluation of lead telluride/bismuth antimony telluride nanocomposites for thermoelectric applications

NASA Astrophysics Data System (ADS)

Ganguly, Shreyashi; Zhou, Chen; Morelli, Donald; Sakamoto, Jeffrey; Uher, Ctirad; Brock, Stephanie L.

2011-12-01

Heterogeneous nanocomposites of p-type bismuth antimony telluride (Bi 2- xSb xTe 3) with lead telluride (PbTe) nanoinclusions have been prepared by an incipient wetness impregnation approach. The Seebeck coefficient, electrical resistivity, thermal conductivity and Hall coefficient were measured from 80 to 380 K in order to investigate the influence of PbTe nanoparticles on the thermoelectric performance of nanocomposites. The Seebeck coefficients and electrical resistivities of nanocomposites decrease with increasing PbTe nanoparticle concentration due to an increased hole concentration. The lattice thermal conductivity decreases with the addition of PbTe nanoparticles but the total thermal conductivity increases due to the increased electronic thermal conductivity. We conclude that the presence of nanosized PbTe in the bulk Bi 2- xSb xTe 3 matrix results in a collateral doping effect, which dominates transport properties. This study underscores the need for immiscible systems to achieve the decreased thermal transport properties possible from nanostructuring without compromising the electronic properties.

Cadmium in the Coastal Upwelling Area Adjacent to the California Mexico Border

NASA Astrophysics Data System (ADS)

Segovia-Zavala, J. A.; Delgadillo-Hinojosa, F.; Alvarez-Borrego, S.

1998-04-01

Cadmium concentrations ([Cd]) were measured in samples from the water column of the coastal upwelling zone adjacent to the California - Mexico border. Temperature and nutrient distributions showed an intense upwelling event during our sampling. Lowest [Cd] were found at locations offshore (50 km) (0·03-0·058 nM), whereas the maximum concentrations were found inshore (0·14-0·166 nM). Both nutrients and [Cd] were enriched in coastal waters. Our inshore [Cd] values are about 25% of those reported for waters off central California. This is possibly due to the intrusion of oligotrophic waters from the eastern edge of the North Pacific Central Gyre to the Southern California Bight. Multivariate analysis indicates that high [Cd]s were associated with high phytoplankton biomass, nutrients and low temperature. Our data present no evidence of a [Cd] gradient due to the San Diego and Tijuana sewage discharges, which indicates that they maintain a very local effect.

The Wavelength-Dispersive Spectrometer and Its Proposed Use in the Analytical Electron Microscope

NASA Technical Reports Server (NTRS)

Goldstein, Joseph I.; Lyman, Charles E.; Williams, David B.

1989-01-01

The Analytical Electron Microscope (AEM) equipped with a wavelength-dispersive spectrometer (WDS) should have the ability to resolve peaks which normally overlap in the spectra from an energy-dispersive spectrometer (EDS). With a WDS it should also be possible to measure lower concentrations of elements in thin foils due to the increased peak-to-background ratio compared with EDS. The WDS will measure X-ray from the light elements (4 less than Z less than 1O) more effectively. This paper addresses the possibility of interfacing a compact WDS with a focussing circle of approximately 4 cm to a modem AEM with a high-brightness (field emission) source of electrons.

Functional studies of the parotid and pancreas glands in amyotrophic lateral sclerosis

PubMed Central

Charchaflie, R. J.; Fernandez, L. Bustos; Perec, C. J.; Gonzalez, E.; Marzi, A.

1974-01-01

Functional studies of the pancreas and parotid glands are reported in 17 patients with amyotrophic lateral sclerosis (ALS). The exocrine function of the pancreas was studied by measuring amylase concentration after stimulation with the endogenous secretin-pancreozymine test (ESP). Under these conditions, the pancreatic amylase concentration in ALS patients was found to be markedly decreased by about 45% when compared with those of healthy control subjects. Different conclusions in the literature about a possible impairment of the exocrine pancreas in ALS patients induced us to study the function of the parotid gland, which has close structural, functional, and physiopathological relationship with the pancreas. Flow rate and bicarbonate concentration of parotid saliva were measured after indirect stimulation (intraoral citric acid) and direct stimulation (pilocarpine). After indirect stimulation, both parotid flow rate and bicarbonate concentration from ALS patients were found to be decreased by about 66% and 70% respectively, when compared with controls. On the other hand, direct stimulation with pilocarpine in ALS patients elicited normal responses in both flow rate and bicarbonate concentration of saliva. It is concluded that the pancreatic and parotid deficiencies observed in ALS patients do not indicate primary disease of these exocrine glands. This interpretation is further emphasized by the results obtained by a sweat test, plasma osmolarity, and sialographic studies. The possibility that the gland impairments observed might be due to modifications of the neuroendocrine mechanisms regulating their secretory activity is suggested. PMID:4852110

Physical-chemical examination of the N2O3-SO3-H2O system

NASA Technical Reports Server (NTRS)

Linstroem, C.; Malyska, G.

1977-01-01

It was found that when (NO)HSO4 is added to absolute H2SO4, specific conductivity rises sharply, possibly due to an increase in mutual interionic effects and viscosity as the (NO)HSO4 concentration rises. The addition of SO3 to the solution yielded a precipitate; a combination of analysis, IR spectroscopy and X-ray diffraction techniques indicated that this precipitate was (NO)HS2O7.

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

Simon, S.L.

Root uptake of /sup 226/Ra, /sup 210/Pb and /sup 210/Po by mature sagebrush was studied using a soil injection method for spiking the soil with minimal root disturbance. The main objective was to measure vegetation concentrations and determine concentration ratios (CR's) due to root uptake as a function of time in mature big sagebrush. Concentration ratios obtained in mature vegetation and in steady-state situations may be valuable in assessing the impact of uranium mining and milling. The vegetation was sampled approximately every 3 months for a 2 year period. Significant levels of activity were detected in the vegetation beginning atmore » the first sampling (81 days after soil injection for /sup 226/Ra, 28 days for /sup 210/Pb and /sup 210/Po). There was an exponential decrease in concentration to an apparent steady-state value. Mean values (geometric) of the data pooled over the second year period indicated that the steady-state CR's for /sup 226/Ra, /sup 210/Pb and /sup 210/Po, as determined in mature sagebrush, were 0.04, 0.009, and 0.08, respectively. A three compartment mathematical model was formulated to help understand mechanisms of plant uptake and to predict, if possible, the concentration of /sup 226/Ra, /sup 210/Pb and /sup 210/Po in vegetation as a function of time after soil spiking. A numerical solution was determined by 'calibrating' the general model solution with constants determined from regressions of concentrations in vegetation, soil leaching and leaf leaching data. Validation of the model is currently not possible because of an absence of similar time-dependent uptake studies. 168 refs., 19 figs., 18 tabs.« less

Multimedia Model for Polycyclic Aromatic Hydrocarbons (PAHs) and Nitro-PAHs in Lake Michigan

PubMed Central

2015-01-01

Polycyclic aromatic hydrocarbon (PAH) contamination in the U.S. Great Lakes has long been of concern, but information regarding the current sources, distribution, and fate of PAH contamination is lacking, and very little information exists for the potentially more toxic nitro-derivatives of PAHs (NPAHs). This study uses fugacity, food web, and Monte Carlo models to examine 16 PAHs and five NPAHs in Lake Michigan, and to derive PAH and NPAH emission estimates. Good agreement was found between predicted and measured PAH concentrations in air, but concentrations in water and sediment were generally under-predicted, possibly due to incorrect parameter estimates for degradation rates, discharges to water, or inputs from tributaries. The food web model matched measurements of heavier PAHs (≥5 rings) in lake trout, but lighter PAHs (≤4 rings) were overpredicted, possibly due to overestimates of metabolic half-lives or gut/gill absorption efficiencies. Derived PAH emission rates peaked in the 1950s, and rates now approach those in the mid-19th century. The derived emission rates far exceed those in the source inventories, suggesting the need to reconcile differences and reduce uncertainties. Although additional measurements and physiochemical data are needed to reduce uncertainties and for validation purposes, the models illustrate the behavior of PAHs and NPAHs in Lake Michigan, and they provide useful and potentially diagnostic estimates of emission rates. PMID:25373871

Seasonal and interannual variability of dissolved oxygen around the Balearic Islands from hydrographic data

NASA Astrophysics Data System (ADS)

Balbín, R.; López-Jurado, J. L.; Aparicio-González, A.; Serra, M.

2014-10-01

Oceanographic data obtained between 2001 and 2011 by the Spanish Institute of Oceanography (IEO, Spain) have been used to characterise the spatial distribution and the temporal variability of the dissolved oxygen around the Balearic Islands (Mediterranean Sea). The study area includes most of the Western Mediterranean Sea, from the Alboran Sea to Cape Creus, at the border between France and Spain. Dissolved oxygen (DO) at the water surface is found to be in a state of equilibrium exchange with the atmosphere. In the spring and summer a subsurface oxygen supersaturation is observed due to the biological activity, above the subsurface fluorescence maximum. Minimum observed values of dissolved oxygen are related to the Levantine Intermediate Waters (LIW). An unusual minimum of dissolved oxygen concentrations was also recorded in the Alboran Sea Oxygen Minimum Zone. The Western Mediterranean Deep Waters (WMDW) and the Western Intermediate Waters (WIW) show higher values of dissolved oxygen than the Levantine Intermediate Waters due to their more recent formation. Using these dissolved oxygen concentrations it is possible to show that the Western Intermediate Waters move southwards across the Ibiza Channel and the deep water circulates around the Balearic Islands. It has also been possible to characterise the seasonal evolution of the different water masses and their dissolved oxygen content in a station in the Algerian sub-basin.

Twentieth century bipolar seesaw of the Arctic and Antarctic surface air temperatures

NASA Astrophysics Data System (ADS)

Chylek, Petr; Folland, Chris K.; Lesins, Glen; Dubey, Manvendra K.

2010-04-01

Understanding the phase relationship between climate changes in the Arctic and Antarctic regions is essential for our understanding of the dynamics of the Earth's climate system. In this paper we show that the 20th century de-trended Arctic and Antarctic temperatures vary in anti-phase seesaw pattern - when the Arctic warms the Antarctica cools and visa versa. This is the first time that a bi-polar seesaw pattern has been identified in the 20th century Arctic and Antarctic temperature records. The Arctic (Antarctic) de-trended temperatures are highly correlated (anti-correlated) with the Atlantic Multi-decadal Oscillation (AMO) index suggesting the Atlantic Ocean as a possible link between the climate variability of the Arctic and Antarctic regions. Recent accelerated warming of the Arctic results from a positive reinforcement of the linear warming trend (due to an increasing concentration of greenhouse gases and other possible forcings) by the warming phase of the multidecadal climate variability (due to fluctuations of the Atlantic Ocean circulation).

Volatile organic compounds in fourteen U.S. retail stores.

PubMed

Nirlo, E L; Crain, N; Corsi, R L; Siegel, J A

2014-10-01

Retail buildings have a potential for both short-term (customer) and long-term (occupational) exposure to indoor pollutants. However, little is known about volatile organic compound (VOC) concentrations in the retail sector and influencing factors, such as ventilation, in-store activities, and store type. We measured VOC concentrations and ventilation rates in 14 retail stores in Texas and Pennsylvania. With the exception of formaldehyde and acetaldehyde, VOCs were present in retail stores at concentrations well below health guidelines. Indoor formaldehyde concentrations ranged from 4.6 ppb to 67 ppb. The two mid-sized grocery stores in the sample had the highest levels of ethanol and acetaldehyde, with concentrations up to 2.6 ppm and 92 ppb, respectively, possibly due to the preparation of dough and baking activities. Indoor-to-outdoor concentration ratios indicated that indoor sources were the main contributors to indoor VOC concentrations for the majority of compounds. There was no strong correlation between ventilation and VOC concentrations across all stores. However, increasing the air exchange rates at two stores led to lower indoor VOC concentrations, suggesting that ventilation can be used to reduce concentrations for some specific stores. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Gas exchange, antioxidants and foliar injuries in saplings of a tropical woody species exposed to ozone.

PubMed

Pina, Juliana M; Moraes, Regina M

2010-05-01

Ozone (O(3)) reaches phytotoxical concentrations in the tropics, but the sensitivity of tropical plant species to O(3) remains unknown. Visible foliar injuries, carbon assimilation (A(sat)), stomatal conductance, superoxide dismutase enzyme (SOD) activity and ascorbic acid concentration (AA) were evaluated in different-aged leaves of Psidium guajava 'Paluma' saplings. We hypothesized that the old leaves are less capable of combating the stress induced by O(3) and hence exhibit more severe leaf injuries. Three O(3) exposure experiments were performed with 'Paluma' saplings in sites with high O(3) concentration and also under filtered air conditions. The exposure experiments corresponding to the seasons spring/2006, summer and autumn/2007. The decrease of A(sat) was greater in old leaves of saplings exposed to O(3), except in the second experiment, when the AA concentrations were more pronounced than in the other experiments. In second experiment, O(3) uptake was similar to that of the first experiment, but the injuries were less severe, probably due to the high AA concentrations. It was not possible to identify a pattern of superoxide dismutase enzyme (SOD) activity due to the high variability in the results from O(3) exposed and reference saplings. O(3) uptake/A(sat) was higher in leaves exhibiting greater injury, suggesting that decrease in A(sat) may have been the main feature associated with the visible foliar symptons. Copyright 2009 Elsevier Inc. All rights reserved.

Black carbon trends in southwestern Iberia in the context of the financial and economic crisis. The role of bioenergy.

PubMed

Malico, Isabel; Pereira, Sérgio Nepomuceno; Costa, Maria João

2017-01-01

Since black carbon concentrations are useful to reveal changes in anthropogenic activities, measurements taken from 2007 to 2015 in a Portuguese city are used to assess to which extent the ambient air was impacted by the economic crisis. The average black carbon concentrations are representative of an urban area of small size (1.3 ± 1.3 μg m -3 ). The highest concentrations are observed in the heating season, being biomass combustion one of the causes for the high values. The daily cycle of black carbon concentrations presents both morning and evening peaks, mainly due to road traffic and, in the heating season, to domestic heating as well. The yearly averaged black carbon mass concentrations decreased 33 % from 2007 to 2015, possibly due to a combination of the economic recession and environmental legislation. The reduction in road traffic led to a decrease in the daily morning peak from 2007 to 2015. This reduction was not followed by a decrease in the evening peak, explained by an increase in biomass burning. Biomass is the cheapest heating fuel in Portugal, and its consumption increased in the aftermath of the economic crisis. The use of bioenergy is an alternative to fossil fuels and presents many advantages. However, energy policies should discourage inefficient biomass burning and promote better ways of exploiting the available energy resources and emission air pollution mitigation strategies.

Dual aging behaviour in a clay-polymer dispersion.

PubMed

Zulian, Laura; Augusto de Melo Marques, Flavio; Emilitri, Elisa; Ruocco, Giancarlo; Ruzicka, Barbara

2014-07-07

Clay-polymer compounds have recently attracted increasing attention due to their intriguing physical properties in colloidal science and their rheological non-trivial behaviour in technological applications. Aqueous solutions of Laponite clay spontaneously age from a liquid up to an arrested state of different nature (gel or glass) depending on the colloidal volume fraction and ionic strength. We have investigated, through dynamic light scattering, how the aging dynamics of Laponite dispersions at fixed clay concentration (Cw = 2.0%) is modified by the addition of various amounts of poly(ethylene oxide) (PEO) (CPEO = (0.05 ÷ 0.50) %) at two different molecular weights (Mw = 100 kg mol(-1) and Mw = 200 kg mol(-1)). A surprising and intriguing phenomenon has been observed: the existence of a critical polymer concentration C that discriminates between two different aging dynamics. With respect to pure Laponite systems the aging will be assisted (faster) or hindered (slower) for PEO concentrations respectively lower (CPEO < C) or higher (CPEO > C) than the critical concentration. In this way a control on the aging dynamics of PEO-Laponite systems is obtained. A possible explanation based on the balance of competitive mechanisms related to the progressive saturation of the clay surface by polymers is proposed. This study shows how a real control on the aging speed of the PEO-Laponite system is at hand and renders possible a real control of the complex interparticle interaction potential.

Pressure-volume (P-V) curves in Atriplex nummularia Lindl. for evaluation of osmotic adjustment and water status under saline conditions.

PubMed

Teixeira Lins, Cíntia Maria; Rodrigues de Souza, Edivan; Farias de Melo, Hidelblandi; Silva Souza Paulino, Martha Katharinne; Dourado Magalhães, Pablo Rugero; Yago de Carvalho Leal, Lucas; Bentzen Santos, Hugo Rafael

2018-03-01

The survival of Atriplex nummularia plants in saline environments is possible mainly due to the presence of salt-accumulating epidermal vesicles. Commonly, destructive methods, such as plant material maceration and subsequent reading in osmometers, are employed in studies on water relations and osmotic adjustment and are inconvenient due to their underestimation of the total water potential inside the cells, which can cause overestimation of an osmotic adjustment that is not present. As a result, methods that preserve leaf structure, such as pressure-volume (P-V) curves, which take into consideration only the salts that compose the symplastic solution, are more adequate. Thus, the main objectives of this study were to evaluate the effect of determination methods of osmotic potential (Ψ o ) in Atriplex nummularia through destructive and leaf structure-preserving techniques and to determine the water relations of the species under increasing NaCl concentrations. Plants were subjected to daily irrigations, maintaining soil moisture at 80% of field capacity, with solutions of increasing NaCl concentration (0, 0.05, 0.1, 0.2, 0.25 and 0.3 M) for 84 days. Water potential, osmotic potential and osmotic adjustment were determined. In addition, P-V curves were constructed using pressure chambers. Water and osmotic potentials decreased linearly with increasing NaCl concentration in the irrigation solution. The main discrepancies observed were related to the osmotic adjustments determined through maceration and P-V curves. Based on the present research, it was possible to conclude that in studies with species that have salt-accumulating vesicles in the epidermis, such as the plants in the genus Atriplex, constructing P-V curves is more adequate than destructive methods. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Comparison of two approaches to quantify anthropogenic CO2 in the ocean: Results from the northern Indian Ocean

NASA Astrophysics Data System (ADS)

Coatanoan, C.; Goyet, C.; Gruber, N.; Sabine, C. L.; Warner, M.

2001-03-01

This study compares two recent estimates of anthropogenic CO2 in the northern Indian Ocean along the World Ocean Circulation Experiment cruise II [Goyet et al., 1999; Sabine et al., 1999]. These two studies employed two different approaches to separate the anthropogenic CO2 signal from the large natural background variability. Sabine et al. [1999] used the ΔC* approach first described by Gruber et al. [1996], whereas Goyet et al. [1999] used an optimum multiparameter mixing analysis referred to as the MIX approach. Both approaches make use of similar assumptions in order to remove variations due to remineralization of organic matter and the dissolution of calcium carbonates (biological pumps). However, the two approaches use very different hypotheses in order to account for variations due to physical processes including mixing and the CO2 solubility pump. Consequently, substantial differences exist in the upper thermocline approximately between 200 and 600 m. Anthropogenic CO2 concentrations estimated using the ΔC* approach average 12 ± 4 μmol kg-1 higher in this depth range than concentrations estimated using the MIX approach. Below ˜800 m, the MIX approach estimates slightly higher anthropogenic CO2 concentrations and a deeper vertical penetration. Despite this compensatory effect, water column inventories estimated in the 0-3000 m depth range by the ΔC* approach are generally ˜20% higher than those estimated by the MIX approach, with this difference being statistically significant beyond the 0.001 level. We examine possible causes for these differences and identify a number of critical additional measurements that will make it possible to discriminate better between the two approaches.

Mercury-sensitive water channels as possible sensors of water potentials in pollen

PubMed Central

Hill, Adrian E.

2013-01-01

The growing pollen tube is central to plant reproduction and is a long-standing model for cellular tip growth in biology. Rapid osmotically driven growth is maintained under variable conditions, which requires osmosensing and regulation. This study explores the mechanism of water entry and the potential role of osmosensory regulation in maintaining pollen growth. The osmotic permeability of the plasmalemma of Lilium pollen tubes was measured from plasmolysis rates to be 1.32±0.31×10–3 cm s–1. Mercuric ions reduce this permeability by 65%. Simulations using an osmotic model of pollen tube growth predict that an osmosensor at the cell membrane controls pectin deposition at the cell tip; inhibiting the sensor is predicted to cause tip bursting due to cell wall thinning. It was found that adding mercury to growing pollen tubes caused such a bursting of the tips. The model indicates that lowering the osmotic permeability per se does not lead to bursting but rather to thickening of the tip. The time course of induced bursting showed no time lag and was independent of mercury concentration, compatible with a surface site of action. The submaximal bursting response to intermediate mercuric ion concentration was independent of the concentration of calcium ions, showing that bursting is not due to a competitive inhibition of calcium binding or entry. Bursting with the same time course was also shown by cells growing on potassium-free media, indicating that potassium channels (implicated in mechanosensing) are not involved in the bursting response. The possible involvement of mercury-sensitive water channels as osmosensors and current knowledge of these in pollen cells are discussed. PMID:24098048

Trace metals in suspended particles, sediments and Asiatic clams (Corbicula fluminea) of the Río de la Plata Estuary, Argentina.

PubMed

Bilos, C; Colombo, J C; Presa, M J

1998-01-01

Suspended particulate matter (SPM), sandy sediments and Asiatic clams were collected at seven sites along 150 km of the Río de la Plata coast to assess the magnitude of trace metal pollution in the area. Metal concentrations in SPM (Cu: 7.4-109; Cr: 75-408; Mn: 525-1341 microg(-1)), sediments (Cr: 16-27; Zn: 26-99; Mn: 221-489 microg(-1)) and bivalves (Cd: 0.5-1.9; Ni: 1.3-6.4; Cr: 1.3-11; Mn: 15-81; Cu: 28-89; Zn: 118-316 microg g(-1)) are comparable to those reported for other moderately polluted world rivers. Cu levels in Asiatic clams are among the highest, similar to those reported for heavily polluted sites. SPM Cu and Cr concentrations displayed a clear geographical trend with values increasing with proximity to major urban centers. Sediments showed a less clear pattern possibly due to their coarse nature (>98% sand) and higher proportion of mineral-associated residual metals. The clams showed a complex pattern due to the variability introduced by size-related factors and the natural dynamics of SPM in the estuary. Cr and Mn showed an apparent reverse industrial trend with higher concentrations in clams collected at distant stations near the turbidity maximum zone, possibly reflecting enhanced particle retention. Cu, Cd and Ni showed no clear geographical pattern, whereas Zn increased in the clams collected in the most industrialized area. A significant relationship with clam size was observed for Cu (positive) and Zn (negative) suggesting different physiological requirements for both metals with age. A principal component analysis confirmed these geographical and size-related trends.

Vitamin B(12) Immunoassay on Roche Elecsys 2010: Effects of High Excess Concentration of Serum Vitamin B(12) in CKD Patients on Parenteral Administration.

PubMed

Basu, Surupa; Chaudhuri, Subimal

2011-10-01

Vitamin B(12) being water soluble is excreted in the urine when administered in excess. The probability of finding an abnormally excess serum concentration would be almost surreal. We report a peculiar clinical situation that may impact the vitamin B(12) immunoassay on the Roche Elecsys 2010 due to excess analyte concentration. In separate episodes (Feb and June 2010), the Biochemistry laboratory of a tertiary-care hospital, Kolkata, India, encountered two critically ill patients with background chronic kidney disease (CKD), low urine output, and on cyanocoabalamin supplementation, who had serum vitamin B(12) concentrations far exceeding expected values; even post dialysis. The B(12) assays (pmol/l) were performed using electrochemiluminiscence immunoassay on Roche Elecsys 2010, the assay validity confirmed by concomitant quality control runs. The immunoassays failed to deliver results, flagged with "signal level below limit". Biotin therapy was ruled out as a possible interferent. In the first episode, re-assay of a repeat draw yielded same outcome; outsourcing on Immulite provided concentration of >738 pmol/l. Serial dilution gave result of >29520 pmol/l on Elecsys 2010. In the second, we gained from past experience. Vitamin B(12) concentration >59040 pmol/l was conveyed to the treating nephrologist the very day. The B(12) immunoassay on the Elecsys 2010 employs sequential incubation steps for competitive binding that is compromised in the event of abnormally excess B(12) concentration in patient sera akin to the prozone effect. This knowledge may be beneficial while assaying sera of CKD patients to avoid financial loss due unnecessary repeats and delay in turnaround time.

Storm drains are sources of human fecal pollution during dry weather in three urban southern California watersheds.

PubMed

Sercu, Bram; Van De Werfhorst, Laurie C; Murray, Jill; Holden, Patricia A

2009-01-15

Coastal urbanized areas in Southern California experience frequent beach water quality warnings in summer due to high concentrations of fecal indicator bacteria (FIB). Remediation can be difficult, as sources are often unknown. During two summers, we sampled three urbanized watersheds in Santa Barbara, CA at sites with historically high FIB concentrations to determine if human fecal matter was influencing water quality. By quantification of a human-specific Bacteroides marker (HBM), human waste was evidenced throughout both transects, and concentrations were highest in the discharges of several flowing storm drains. The HBM concentrations in storm drain discharges varied by up to 5 orders of magnitude on the same day. While the exact points of entry into the storm drain systems were not definitively determined, further inspection of the drain infrastructure suggested exfiltrating sanitary sewers as possible sources. The HBM and FIB concentrations were not consistently correlated, although the exclusive occurrence of high HBM concentrations with high FIB concentrations warrants the use of FIB analyses for a first tier of sampling. The association of human fecal pollution with dry weather drainage could be a window into a larger problem for other urbanized coastal areas with Mediterranean-type climates.

Variability in Saponin Content, Cancer Antiproliferative Activity and Physicochemical Properties of Concentrated Agave Sap.

PubMed

Santos-Zea, Liliana; Rosas-Pérez, Aratza Mireya; Leal-Díaz, Ana María; Gutiérrez-Uribe, Janet A

2016-08-01

Concentrated agave sap (CAS) has gained popularity as an unrefined sweetener. It is obtained by boiling "aguamiel" that contains phytochemicals with diverse bioactivities. Saponins have been the most widely studied agave phytochemicals due to their cancer antiproliferative effect but their concentration may vary due to maturity of the agave plant and collection site. In this study, 18 CAS samples produced in different states of Mexico were analyzed using multivariate methods to determine which physicochemical or phytochemical parameters were responsible for variation. Additionally, extracts with different saponin profiles were tested to determine possible correlations with antiproliferative activity. Total soluble solids, pH, and water activity were similar to those reported for other agave sweeteners. Antioxidant capacity of samples was correlated to browning index. Eleven steroidal saponins were found in CAS samples and they were the main source of variability. Magueyoside B, a kammogenin tetraglycoside, was the most abundant saponin in all samples. With respect to bioactivity, multivariate analysis indicated that magueyoside B and a gentrogenin tetraglycoside were compounds strongly related with bioactivity. CAS from Hidalgo, Puebla, and Veracruz had higher concentration of magueyoside B than from the other kamogenin tetraglycoside found in the samples from other Mexican states. These results could be used as a first approach to characterize and standardize CAS to validate the potential health benefits derived from its consumption. © 2016 Institute of Food Technologists®

[Cobalt(III)-EDTA] - Reduction by Thermophilic Methanogen Methanothermobacter Thermautotrophicus

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

Singh, Rajesh; Dong, Hailiang; Liu, Deng

2015-06-30

Cobalt is a metal contaminant at high temperature radioactive waste disposal sites. In previous studies have largely focused on mesophilic microorganisms to remediate cobalt, despite the presence of thermophilic microorganisms at such sites. In this study,Methanothermobacter thermautotrophicus, a thermophilic methanogen, was used to reduce Co(III) in the form of [Co(III)–EDTA] -. Bioreduction experiments were conducted in a growth medium with H 2/CO 2 as a growth substrate at initial Co(III) concentrations of 1, 2, 4, 7, and 10 mM. At low Co(III) concentrations (< 4 mM), a complete reduction was observed within a week. Wet chemistry, X-ray absorption near-edge structuremore » (XANES) and electron paramagnetic resonance (EPR) analyses were all consistent in revealing the reduction kinetics. But, at higher concentrations (7 and 10 mM) the reduction extents only reached 69.8% and 48.5%, respectively, likely due to the toxic effect of Co(III) to the methanogen cells as evidenced by a decrease in total cellular protein at these Co(III) concentrations. Methanogenesis was inhibited by Co(III) bioreduction, possibly due to impaired cell growth and electron diversion from CO 2 to Co(III). Overall, our results demonstrated the ability of M. thermautotrophicus to reduce Co(III) to Co(II) and its potential application for remediating 60Co contaminant at high temperature subsurface radioactive waste disposal sites.« less

Isocyanatocyclohexane and isothiocyanatocyclohexane levels in urban and industrial areas and possible emission-related activities

NASA Astrophysics Data System (ADS)

Gallego, E.; Roca, F. X.; Perales, F.; Ribes, A.; Carrera, G.; Guardino, X.; Berenguer, M. J.

Isocyanatocyclohexane and isothiocyanatocyclohexane are becoming relevant compounds in urban and industrial air, as they are used in important amounts in automobile industry and building insulation, as well as in the manufacture of foams, rubber, paints and varnishes. Glass multi-sorbent tubes (Carbotrap, Carbopack, Carboxen) were connected to LCMA-UPC pump samplers for the retention of iso- and isothiocyanatocyclohexanes. The analysis was performed by automatic thermal desorption (ATD) coupled with capillary gas chromatography (GC)/mass spectrometry detector (MSD). TD-GC/MS was chosen as analytical method due to its versatility and the possibility of analysis of a wide range of volatility and polarity VOC in air samples. The method was satisfactory sensitive, selective and reproducible for the studied compounds. The concentrations of iso- and isothioisocyanatocyclohexanes were evaluated in different urban, residential and industrial locations from extensive VOC air quality and odour episode studies in several cities in the Northeastern edge of Spain. Around 200-300 VOC were determined qualitatively in each sample. Higher values of iso- and isothiocyanatocyclohexane were found in industrial areas than in urban or residential locations. The concentrations ranged between n.d.-246 and n.d.-29 μg m -3 for isocyanatocyclohexane and isothiocyanatocyclohexane, respectively, for industrial areas. On the other hand, urban and residential locations showed concentrations ranging between n.d.-164 and n.d.-29 μg m -3 for isocyanatocyclohexane and isothiocyanatocyclohexane, respectively. The site location (urban or industrial), the kind and nearness of possible iso- and isothiocyanatocyclohexane emission activities (industrial or building construction) and the changes of wind regimes throughout the year have been found the most important factors influencing the concentrations of these compounds in the different places.

Deposition and solubility of airborne metals to four plant species grown at varying distances from two heavily trafficked roads in London.

PubMed

Peachey, C J; Sinnett, D; Wilkinson, M; Morgan, G W; Freer-Smith, P H; Hutchings, T R

2009-01-01

In urban areas, a highly variable mixture of pollutants is deposited as particulate matter. The concentration and bioavailability of individual pollutants within particles need to be characterised to ascertain the risks to ecological receptors. This study, carried out at two urban parks, measured the deposition and water-solubility of metals to four species common to UK urban areas. Foliar Cd, Cr, Cu, Fe, Ni, Pb and Zn concentrations were elevated in at least one species compared with those from a rural control site. Concentrations were, however, only affected by distance to road in nettle and, to a lesser extent, birch leaves. Greater concentrations of metal were observed in these species compared to cypress and maple possibly due to differences in plant morphology and leaf surfaces. Solubility appeared to be linked to the size fraction and, therefore, origin of the metal with those present predominantly in the coarse fraction exhibiting low solubility.

Bioaccumulation of potentially toxic trace elements in benthic organisms of Admiralty Bay (King George Island, Antarctica).

PubMed

Majer, Alessandra Pereira; Petti, Mônica Angélica Varella; Corbisier, Thais Navajas; Ribeiro, Andreza Portella; Theophilo, Carolina Yume Sawamura; Ferreira, Paulo Alves de Lima; Figueira, Rubens Cesar Lopes

2014-02-15

Data about the concentration, accumulation and transfer of potentially toxic elements in Antarctic marine food webs are essential for understanding the impacts of these elements, and for monitoring the pollution contribution of scientific stations, mainly in Admiralty Bay due to the 2012 fire in the Brazilian scientific station. Accordingly, the concentration of As, Cd, Cu, Ni, Pb and Zn was measured in eight benthic species collected in the 2005/2006 austral summer and the relationship between concentration and trophic position (indicated by δ(15)N values) was tested. A wide variation in metal content was observed depending on the species and the element. In the studied trophic positions, it was observed bioaccumulation for As, Cd and Pb, which are toxic elements with no biological function. In addition, Cd showed a positive relationship between concentration and trophic level suggesting the possible biomagnification of this element. Copyright © 2013 Elsevier Ltd. All rights reserved.

Process optimization and analysis of product inhibition kinetics of crude glycerol fermentation for 1,3-Dihydroxyacetone production.

PubMed

Dikshit, Pritam Kumar; Padhi, Susant Kumar; Moholkar, Vijayanand S

2017-11-01

In present study, statistical optimization of biodiesel-derived crude glycerol fermentation to DHA by immobilized G. oxydans cells over polyurethane foam is reported. Effect of DHA (product) inhibition on crude glycerol fermentation was analyzed using conventional biokinetic models and new model that accounts for both substrate and product inhibition. Optimum values of fermentation parameters were: pH=4.7, temperature=31°C, initial substrate concentration=20g/L. At optimum conditions, DHA yield was 89% (17.83g/L). Effect of product inhibition on fermentation was trivial for DHA concentrations ≤30g/L. At higher concentrations (≥50g/L), kinetics and yield of fermentation showed marked reduction with sharp drop in V max and K S values. Inhibition effect was more pronounced for immobilized cells due to restricted transport of fermentation mixture across polyurethane foam. Retention of fermentation mixture in immobilized matrix resulted in higher localized DHA concentration that possibly enhanced inhibition effect. Copyright © 2017 Elsevier Ltd. All rights reserved.

Groundwater fluoride contamination and its possible health implications in Indi taluk of Vijayapura District (Karnataka State), India.

PubMed

Ugran, Vidyavati; Desai, Naveen N; Chakraborti, Dipankar; Masali, Kallappa A; Mantur, Prakash; Kulkarni, Shreepad; Deshmukh, Niranjan; Chadchan, Kailash S; Das, Swastika N; Tanksali, Anuradha S; Arwikar, Asha S; Guggarigoudar, Suresh P; Vallabha, Tejaswini; Patil, Shailaja S; Das, Kusal K

2017-10-01

Groundwater fluoride concentration and fluoride-related health problems were studied in twenty-two villages of Indi taluk of Vijayapura district, Karnataka, India. Present study (2015) was also used to compare groundwater fluoride concentration in same 22 villages with previous government report (2000). Groundwater fluoride concentrations of 62 bore wells of 22 villages were analyzed by using an ion-sensitive electrode. A total of 660 adults and 600 children were screened for fluorosis symptoms and signs. Sixty clinically suspected fluorosis patients' urine samples were further analyzed for fluoride. The mean value (1.22 ± 0.75 mg/L) of fluoride concentration of 62 bore wells and 54.83 % bore wells with ≥1.0 mg/L of fluoride concentrations in Indi taluk indicates higher than the permissible limit of drinking water fluoride concentration recommended for India. Clinical symptoms like arthritis, joint pains, gastrointestinal discomfort and lower limb deformities with high urinary fluoride concentrations in some subjects suggest fluorosis. Results also showed an increase in groundwater fluoride concentration of the same 22 villages between previous and present study. Preliminary arthritis symptom of the villagers could be due to drinking fluoride-contaminated water. Increase in fluoride concentration with time to the bore wells definitely indicates future danger.

[Pregnancy (conception) in hyper- or hypothyroidism].

PubMed

Corssmit, E P; Wiersinga, W M; Boer, K; Prummel, M F

2001-04-14

Pregnancy is accompanied by changes in thyroid function. Due to the increased synthesis of thyroid binding globulin and the thyroid-stimulating effect of human chorionic gonadotrophin (hCG), serum concentrations of thyroid hormones will increase in the first trimester of pregnancy (total T4, T3). Free T4 levels decrease during the latter half of pregnancy. Hyperthyroidism during pregnancy is usually due to Graves' disease. Definitive therapy may be considered for cases prior to pregnancy, although a medical management as would be given during pregnancy is an equally good option. The medical management of hyperthyroidism consists of a monotherapy with thyreostatics in which the recommended dose needs to be adjusted on the basis of free T4 in the high-normal and thyroid stimulating hormone (TSH) in the low-normal area so as to minimise the risk of foetal hypothyroidism. The transplacental passage of maternal TSH receptor stimulating antibodies may cause foetal hyperthyroidism. Another cause of maternal hyperthyroidism during pregnancy is 'gestational transient thyrotoxicosis', which is associated with high hCG levels during the first trimester of pregnancy. It is nearly always accompanied by hyperemesis gravidarum. Hypothyroidism in pregnancy has negative consequences for the foetus. If the hypothyroidism is apparent prior to pregnancy, it should be corrected before conception (target TSH value of 1 mU/l). If discovered during pregnancy, treatment with levothyroxine should be started as soon as possible. In the case of a pre-existing hypothyroidism a 25-50% increase in the levothyroxine dosage is often needed during the first trimester of pregnancy. This is possibly due to an increased requirement. An adequate serum concentration of T4 is necessary for foetal brain development.

On the accuracy of estimation of basic pharmacokinetic parameters by the traditional noncompartmental equations and the prediction of the steady-state volume of distribution in obese patients based upon data derived from normal subjects.

PubMed

Berezhkovskiy, Leonid M

2011-06-01

The steady-state and terminal volumes of distribution, as well as the mean residence time of drug in the body (V(ss), V(β), and MRT) are the common pharmacokinetic parameters calculated using the drug plasma concentration-time profile C(p) (t) following intravenous (i.v. bolus or constant rate infusion) drug administration. These calculations are valid for the linear pharmacokinetic system with central elimination (i.e., elimination rate being proportional to drug concentration in plasma). Formally, the assumption of central elimination is not normally met because the rate of drug elimination is proportional to the unbound drug concentration at elimination site, although equilibration between systemic circulation and the site of clearance for majority of small molecule drugs is fast. Thus, the assumption of central elimination is practically quite adequate. It appears reasonable to estimate the extent of possible errors in determination of these pharmacokinetic parameters due to the absence of central elimination. The comparison of V(ss), V(β), and MRT calculated by exact equations and the commonly used ones was made considering a simplified physiologically based pharmacokinetic model. It was found that if the drug plasma concentration profile is detected accurately, determination of drug distribution volumes and MRT using the traditional noncompartmental calculations of these parameters from C(p) (t) yields the values very close to that obtained from exact equations. Though in practice, the accurate measurement of C(p) (t), especially its terminal phase, may not always be possible. This is particularly applicable for obtaining the distribution volumes of lipophilic compounds in obese subjects, when the possibility of late terminal phase at low drug concentration is quite likely, specifically for compounds with high clearance. An accurate determination of V(ss) is much needed in clinical practice because it is critical for the proper selection of drug treatment regimen. For that reason, we developed a convenient method for calculation of V(ss) in obese (or underweight) subjects. It is based on using the V(ss) values obtained from pharmacokinetic studies in normal subjects and the physicochemical properties of drug molecule. A simple criterion that determines either the increase or decrease of V(ss) (per unit body weight) due to obesity is obtained. The accurate determination of adipose tissue-plasma partition coefficient is crucial for the practical application of suggested method. Copyright © 2011 Wiley-Liss, Inc.

Sensitivity to experimental data of pollutant site mean concentration in stormwater runoff.

PubMed

Mourad, M; Bertrand-Krajewski, J L; Chebbo, G

2005-01-01

Urban wet weather discharges are known to be a great source of pollutants for receiving waters, which protection requires the estimation of long-term discharged pollutant loads. Pollutant loads can be estimated by multiplying a site mean concentration (SMC) by the total runoff volume during a given period of time. The estimation of the SMC value as a weighted mean value with event runoff volumes as weights is affected by uncertainties due to the variability of event mean concentrations and to the number of events used. This study carried out on 13 catchments gives orders of magnitude of these uncertainties and shows the limitations of usual practices using few measured events. The results obtained show that it is not possible to propose a standard minimal number of events to be measured on any catchment in order to evaluate the SMC value with a given uncertainty.

Cellular lysis of Streptococcus faecalis induced with triton X-100.

PubMed Central

Cornett, J B; Shockman, G D

1978-01-01

Lysis of exponential-phase cultures of Streptococcus faecalis ATCC 9790 was induced by exposure to both anionic (sodium dodecyl sulfate) and nonionic (Triton X-100) surfactants. Lysis in response to sodium dodecyl sulfate was effective only over a limited range of concentrations, whereas Triton X-100-induced lysis occurred over a broad range of surfactant concentrations. The data presented indicate that the bacteriolytic response of growing cells to Triton X-100: (i) was related to the ratio of surfactant to cells and not the surfactant concentration per se; (ii) required the expression of the cellular autolytic enzyme system; and (iii) was most likely due to an effect of the surfactant on components of the autolytic system that are associated with the cytoplasmic membrane. The possibility that Triton X-100 may induce cellular lysis by releasing a lipid inhibitor of the cellular autolytic enzyme is discussed. PMID:97265

Polycyclic aromatic hydrocarbons (PAHs) in atmospheric dustfall from the industrial corridor in Hubei Province, Central China.

PubMed

Zhang, Jiaquan; Qu, Chengkai; Qi, Shihua; Cao, Junji; Zhan, Changlin; Xing, Xinli; Xiao, Yulun; Zheng, Jingru; Xiao, Wensheng

2015-10-01

Thirty atmospheric dustfall samples collected from an industrial corridor in Hubei Province, central China, were analyzed for 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) to investigate their concentrations, spatial distributions, sources, and health risks. Total PAH concentrations (ΣPAHs) ranged from 1.72 to 13.17 µg/g and averaged 4.91 µg/g. High molecular weight (4-5 rings) PAHs averaged 59.67% of the ΣPAHs. Individual PAH concentrations were not significantly correlated with total organic carbon, possibly due to the semi-continuous inputs from anthropogenic sources. Source identification studies suggest that the PAHs were mainly from motor vehicles and biomass/coal combustion. The incremental lifetime cancer risks associated with exposure to PAHs in the dustfall ranged from 10(-4) to 10(-6); these indicate potentially serious carcinogenic risks for exposed populations in the industrial corridor.

Kinetic Study on the Formation of Bimetallic Core-Shell Nanoparticles via Microemulsions

PubMed Central

Tojo, Concha; Vila-Romeu, Nuria

2014-01-01

Computer calculations were carried out to determine the reaction rates and the mean structure of bimetallic nanoparticles prepared via a microemulsion route. The rates of reaction of each metal were calculated for a particular microemulsion composition (fixed intermicellar exchange rate) and varying reduction rate ratios between both metal and metal salt concentration inside the micelles. Model predictions show that, even in the case of a very small difference in reduction potential of both metals, the formation of an external shell in a bimetallic nanoparticle is possible if a large reactant concentration is used. The modification of metal arrangement with concentration was analyzed from a mechanistic point of view, and proved to be due to the different impact of confinement on each metal: the reaction rate of the faster metal is only controlled by the intermicellar exchange rate but the slower metal is also affected by a cage-like effect. PMID:28788260

Less-studied TCE: are their environmental concentrations increasing due to their use in new technologies?

PubMed

Filella, M; Rodríguez-Murillo, J C

2017-09-01

The possible environmental impact of the recent increase in use of a group of technology-critical elements (Nb, Ta, Ga, In, Ge and Te) is analysed by reviewing published concentration profiles in environmental archives (ice cores, ombrotrophic peat bogs, freshwater sediments and moss surveys) and evaluating temporal trends in surface waters. No increase has so far been recorded. The low potential direct emissions of these elements, resulting from their absolute low production levels, make it unlikely that the increasing use of these elements in modern technology has any noticeable effect on their environmental concentrations on a global scale. This holds particularly true for those of these elements that are probably emitted in relatively high amounts from other human activities (i.e., coal combustion and non-ferrous smelting), such as In, the most studied element of the group. Copyright © 2017 Elsevier Ltd. All rights reserved.

Model calculation of Cr dissolution behavior of ODS ferritic steel in high-temperature flowing sodium environment

NASA Astrophysics Data System (ADS)

Ohtsuka, Satoshi; Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Kato, Shoichi; Furukawa, Tomohiro; Kaito, Takeji

2018-07-01

A calculation model was constructed to systematically study the effects of environmental conditions (i.e. Cr concentration in sodium, test temperature, axial temperature gradient of fuel pin, and sodium flow velocity) on Cr dissolution behavior. Chromium dissolution was largely influenced by small changes in Cr concentration (i.e. chemical potential of Cr) in liquid sodium in the model calculation. Chromium concentration in sodium coolant, therefore, should be recognized as a critical parameter for the prediction and management of Cr dissolution behavior in the sodium-cooled fast reactor (SFR) core. Because the fuel column length showed no impact on dissolution behavior in the model calculation, no significant downstream effects possibly take place in the SFR fuel cladding tube due to the much shorter length compared with sodium loops in the SFR plant and the large axial temperature gradient. The calculated profile of Cr concentration along the wall-thickness direction was consistent with that measured in BOR-60 irradiation test where Cr concentration in inlet sodium bulk flow was set at 0.07 wt ppm in the calculation.

Early warning indicators for process failure due to organic overloading by rapeseed oil in one-stage continuously stirred tank reactor, sewage sludge and waste digesters.

PubMed

Kleyböcker, A; Liebrich, M; Verstraete, W; Kraume, M; Würdemann, H

2012-11-01

Early warning indicators for process failures were investigated to develop a reliable method to increase the production efficiency of biogas plants. Organic overloads by the excessive addition of rapeseed oil were used to provoke the decrease in the gas production rate. Besides typical monitoring parameters, as pH, methane and hydrogen contents, biogas production rate and concentrations of fatty acids; carbon dioxide content, concentrations of calcium and phosphate were monitored. The concentration ratio of volatile fatty acids to calcium acted as an early warning indicator (EWI-VFA/Ca). The EWI-VFA/Ca always clearly and reliably indicated a process imbalance by exhibiting a 2- to 3-fold increase 3-7days before the process failure occurred. At this time, it was still possible to take countermeasures successfully. Furthermore, increases in phosphate concentration and in the concentration ratio of phosphate to calcium also indicated a process failure, in some cases, even earlier than the EWI-VFA/Ca. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of added sodium chloride on the molecular environment and photoionization of N,N,N',N'-tetramethylbenzidine in micellar solutions as studied by electron spin echo and electron spin resonance spectroscopy

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

Maldonado, R.; Kevan, L.; Szajdzinska-Pietek, E.

1984-11-01

The electron spin echo modulation (ESEM) and electron spin resonance (ESR) spectra of the cation radical of N,N,N',N'-tetramethylbenzidine (TMB) in frozen sodium dodecyl sulfate (SDS)= and dodecyltrimethylammonium chloride (DTAC) micelles were studied as a function of sodium chloride concentration. TMB/sup +center-dot/ was produced by photoionization at 350 nm of the parent compound in the micelles at 77 K. From the ESEM analysis it is found that the cation--water interactions increase with salt addition in both anionic and cationic micelles to a maximum near 0.2 M NaCl and then decrease somewhat. The increase is interpreted in terms of an increase inmore » the water density at the micellar surface due to an increased surface concentration of hydrated counterions. The decrease may be due to TMB moving further from the polar micellar surface with added salt. From ESR spectra the photoionization yields of TMB at 77 K were determined. For DTAC micelles the yields are found to decrease with salt addition as expected from electrostatic considerations. For SDS micelles the photoionization yields increase for salt concentrations up to about 0.15 M and decrease for greater salt concentrations up to 0.5 M. The initial increase in cation yield correlates with electrostatic expectations. The decrease may be due to TMB moving further from the polar micellar surface with added salt. The possible effect of differing TMB protonation equilibria between anionic and cationic micelles on the photoionization yields was found to be unimportant by adjusting the bulk solution pH. An important conclusion is that salt addition can be used to optimize charge separation for photoionized solutes in anionic micelles.« less

Dielectric Anistropy, Elastic Constants, and Threshold Voltage Measurements of Gold-nanoparticle Colloids in Nematic 5CB

NASA Astrophysics Data System (ADS)

Visco, Angelo; Foust, Jon; Belobradich, Joseph; Mahmood, Rizwan; Zapien, Donald

We have explored electro-optical and thermal properties of gold nanoparticles (GNPs) colloids in 4-cyano- 4'-pentylbiphenyl (5CB) liquid crystals (LCs). GNP's do not readily disperse in a LC host and, so, have been treated with either, 1-Hexane-thiol, 1-Dodecane-thiol, or 1-Octadecyl-thiol. This treatment suppresses the aggregation of GNPs within the 5CB host to a threshold of approximately 0.7% GNP by weight. Our measurements on dodecanethiol and hexanethiol treated GNPs showed an unusual, steep trough in the dielectric anisotropy and elastic constants at a critical concentration of 0.0862 wt. % GNPs in 5CB. Due to the order parameter, we have observed a peak in the transition temperature at the same critical concentration. Above the critical concentration the transition temperatures, dielectric anisotropy, and elastic constants level off to within experimental uncertainty. Measurements of dodecanethiol treated GNPs in 5CB reveal distinctions in the rate of change in dielectric anisotropy as compared to hexanethiol treated GNPs in 5CB. This effect is possibly due to the increased carbon concentration in dodeccanethiol compared to hexanethiol. Attempts to mix the Smectic A (SmA), 8CB liquid crystal using our hexanethiol and dodecanethiol GNPs were unsuccessful for particle sizes of 100nm and 28nm. We suspect that this is due to an insufficient length of the carbon-chain and U.V. spectroscopy measurements may prove useful in characterizing the resulting aggregation. We hope the system will be helpful in modifying the properties of mesophases that may ultimately results in developing new electro-optical devices. Acknowledgements: The funding for the project was provided by Slippery Rock University (2015-2016).

Study on the number density of nanobubbles at varying concentration of ethanol in ethanol-water solution

NASA Astrophysics Data System (ADS)

Rajib, Md. Mahadi; Farzeen, Parisa; Ali, Mohammad

2017-12-01

In recent years, nanobubble technology has drawn great attention due to its extensive incorporation to substantial aspects of science and technology such as water treatment, drug delivery enhancement to cells, solvent and nutritional supplements manufacturing and many others. Bulk nanobubbles may be present in most aqueous solutions, possibly being constantly created by cosmic radiation and agitation and surface nanobubbles are present at most surfaces [1,2]. But, for utilizing these nanobubbles in a definitive way it's important to know whether an added amount of solution making substance has constructive or adverse effect on the nanobubble. In this work, the change of number density of nanobubbles in ethanol-water solution was studied by varying the ethanol concentration.

Optical leak detection of oxygen using IR-laser diodes

NASA Technical Reports Server (NTRS)

Disimile, P. J.; Fox, C.; Toy, N.

1991-01-01

The ability to accurately measure the concentration of gaseous oxygen and its corresponding flow rate is becoming of greater importance. The technique being presented is based on the principal of light attenuation due to the absorption of radiation by the A-band of oxygen which is located in the 759-770 nm wavelength range. With an ability to measure the change in the light transmission to 0.05 percent, a sensitive optical leak detection system which has a rapid time response is possible. In this research program, the application of laser diode technology and its ability to be temperature tuned to a selected oxygen absorption spectral peak has allowed oxygen concentrations as low as 16,000 ppm to be detected.

Preliminary experiments to quantify liquid movement under mimetic vocal fold vibrational forces.

PubMed

Titze, Ingo R; Klemuk, Sarah; Lu, Xiaoying

2014-07-01

Hydration of vocal fold tissues is essential for self-sustained oscillation. Normal regulatory processes of liquid transport to and from the vocal folds would be expected through the autonomic systems, but the possibility exists that liquid movement may occur locally due to vibrational pressures. Such movement may cause regions of lower or higher concentrations of liquid viscosity and therewith changes in phonation threshold pressure. Hyaluronic acid, a glycosaminoglycan that attracts large quantities of free water, may be a key molecule for transporting or localizing liquids. Some preliminary experiments are reported in which attempts were made to move low-concentration HA liquids with vibration. None of the experiments was conclusive, but collectively they lay some groundwork for future explorations.

Empirical orthogonal function analysis of cloud-containing coastal zone color scanner images of northeastern North American coastal waters

NASA Technical Reports Server (NTRS)

Eslinger, David L.; O'Brien, James J.; Iverson, Richard L.

1989-01-01

Empirical-orthogonal-function (EOF) analyses were carried out on 36 images of the Mid-Atlantic Bight and the Gulf of Maine, obtained by the CZCS aboard Nimbus 7 for the time period from February 28 through July 9, 1979, with the purpose of determining pigment concentrations in coastal waters. The EOF procedure was modified so as to include images with significant portions of data missing due to cloud obstruction, making it possible to estimate pigment values in areas beneath clouds. The results of image analyses explained observed variances in pigment concentrations and showed a south-to-north pattern corresponding to an April Mid-Atlantic Bight bloom and a June bloom over Nantucket Shoals and Platts Bank.

Isotropic-nematic phase transition in aqueous sepiolite suspensions.

PubMed

Woolston, Phillip; van Duijneveldt, Jeroen S

2015-01-01

Aqueous suspensions of sepiolite clay rods in water tend to form gels on increase of concentration. Here it is shown how addition of a small amount (0.1% of the clay mass) of a common stabiliser for clay suspensions, sodium polyacrylate, can allow the observation of an isotropic-nematic liquid crystal phase transition. This transition was found to move to higher clay concentrations upon adding NaCl, with samples containing 10(-3) M salt or above only displaying a gel phase. Even samples that initially formed liquid crystals had a tendency to form gels after several weeks, possibly due to Mg(2+) ions leaching from the clay mineral. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

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

Yeslbagg, Y. Ue.; Kuecuekoemeroglu, A.; Kurnaz, A.

Indoor radon studies have been conducted in Artvin, Eastern alack sea region of Turkey using SSNTD type nuclear track detector (CR-39). Radon measurements were done for 4 seasons in 73 dwellings, selected as uniformly distributed as possible. The radon concentrations vary from 21 aq m{sup -3} to 321 aq m{sup -3} with the annual mean concentration of 132 aq m{sup -3} for Artvin. Seasonal variation indoor radon shows high in winter low values in summer. The resulting estimated annual effective dose-equivalent due to inhalation of radon for inhabitants is 3.32 mSv y{sup -1} and the total annual effective dose liesmore » in the range of the action level (3-10 mSv y{sup -1}) recommended by the ICRP.« less

River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons

USGS Publications Warehouse

Corsi, Steven R.; De Cicco, Laura A.; Lutz, Michelle A.; Hirsch, Robert M.

2014-01-01

Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006–2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period.

River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons.

PubMed

Corsi, Steven R; De Cicco, Laura A; Lutz, Michelle A; Hirsch, Robert M

2015-03-01

Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006-2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period. Published by Elsevier B.V.

PFAAs in Fish and Other Seafood Products from Icelandic Waters

PubMed Central

Halldorsson, Thorhallur I.; Gunnlaugsdottir, Helga

2014-01-01

Perfluorinatedalkyl acids (PFAAs) are of growing concern due to possible health effects on humans. Exposure assessments indicate that fish consumption is one of the major sources of perfluorooctane sulfonate (PFOS) exposure to humans, one of the major PFASs, whereas concerns of overestimation of this exposure source have been raised. Therefore, PFAAs concentrations in fish from the North Atlantic (Icelandic fishing grounds) in the flesh of different fish species were investigated along with more detailed analyses of tissue concentrations in cod (Gadus morhua) and lumpfish (Cyclopterus lumpus). Further, fish feed was investigated as a possible source of PFAAs in aquaculture by examining fish meal as feed ingredient. No PFAAs were detected in the edible part of all fish samples, except for PFOS in pollock (Pollachius virens, 0,05 ng/g wet weight). PFOS was the only PFAA detected in the fish meal samples with the exception of PFOSA in blue whiting (Micromesistius poutassou) meal (0,45 ng/g dry weight (d.w.)), where the PFOS concentration was 1,3–13 ng/g d.w. in the capelin (Mallotus villosus) and mackerel (Scomber scombrus) meal samples. The conclusions of the study are that fish commonly consumed from the Icelandic fishing grounds are unlikely to be an important source of PFAAs exposure. PMID:24782899

Action of the chemical agent fipronil on the reproductive process of semi-engorged females of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae). Ultrastructural evaluation of ovary cells.

PubMed

Oliveira, Patrícia Rosa de; Bechara, Gervásio Henrique; Morales, Maria Aparecida Marin; Mathias, Maria Izabel Camargo

2009-06-01

The ovary of the tick Rhipicephalus sanguineus consists of a wall of epithelial cells and a large number of oocytes in five different developmental stages (I-V), which are attached to the wall by a pedicel. The present study provides ultrastructural information on the effects (dose-response) of the acaricide fipronil (Frontline) on ovaries of semi-engorged females of R. sanguineus, as well as it demonstrates some possible defense mechanisms used by oocytes to protect themselves against this chemical agent. Individuals were divided into four groups. Group I was used as control while groups II, III and IV were treated with fipronil at the concentrations of 1, 5 and 10 ppm, respectively. Fipronil at the concentration of 10 ppm had the strongest effect on the development of oocytes. At this concentration, even oocytes that reached the final developmental stage exhibited damaged cell structures. Moreover, the observation in fipronil-treated R. sanguineus ticks of damaged cellular components such as plasmic membrane, mitochondria and protein granules (due to alteration in the protein synthesis), and cellular defense mechanisms such as increase in the amount of cytoplasmic microtubules and large amounts of digestive vacuoles and myelin figures, were only possible by means of ultrastructure.

Possible lin between elevated accumulation of trace elements and canine distemper virus infection in the Caspian seals (Phoca caspica) stranded in 2000 and 2001

NASA Astrophysics Data System (ADS)

Shinsuke, T.; Takashi, K.; Yasumi, A.; Tokutaka, I.; Reiji, K.

2003-05-01

In the Caspian Sea, a die-off of thousands of Caspian seals (Phoca caspica) occurred in 1997 and 2000. While a direct cause for these deaths seems to be canine distemper virus (CDV) infection, immunosuppression due to environmental pollutants is considered as one of the possible explanations for the development of the disease. The purpose of this work is to examine whether exposure to trace metals could be one of the factors involved in the mass mortality of Caspian seals. Concentrations of 13 trace elements weredetermined in liver, kidney and muscle of Caspian seals found stranded along the coasts of the Caspian Sea in 2000 and 2001. Concentrations of toxic elemen ts (Ag, Cd, Hg, Tl and Pb) in the Caspian seals collected in 2000 and 2001 were comparable to or lower than those in healthy Caspian seals collected in 1993 and 1998 and in seals from other regions, suggesting that these elements would not be the causative agent for the death of Caspian seals. In contrast, Zn and Fe concentrations in the stranded Caspian seals were apparently higher than those in seals from other locations. These results suggest the disturbance in homeostatic control and nutritional statu s of essential elements in the stranded Caspian seals.

Egg thiamine status of Lake Ontario salmonines 1995-2004 with emphasis on lake trout

USGS Publications Warehouse

Fitzsimons, J.D.; Williston, B.; Williston, G.; Brown, L.; El-Shaarawi, A.; Vandenbyllaardt, L.; Honeyfeld, D.; Tillitt, D.; Wolgamood, M.; Brown, S.B.

2007-01-01

Alewives (Alosa pseudoharengus), the major prey fish for Lake Ontario, contain thiaminase. They are associated with development of a thiamine deficiency in salmonines which greatly increases the potential for developing an early mortality syndrome (EMS). To assess the possible effects of thiamine deficiency on salmonine reproduction we measured egg thiamine concentrations for five species of Lake Ontario salmonines. From this we estimated the proportion of families susceptible to EMS based on whether they were below the ED20, the egg thiamine concentration associated with 20% mortality due to EMS. The ED20s were 1.52, 2.63, and 2.99 nmol/g egg for Chinook salmon (Oncorhynchus tshawytscha), lake trout (Salvelinus namaycush), and coho salmon (Oncorhynchus kisutch), respectively. Based on the proportion of fish having egg thiamine concentrations falling below the ED20, the risk of developing EMS in Lake Ontario was highest for lake trout, followed by coho (O. kisutch), and Chinook salmon, with the least risk for rainbow trout (O. mykiss). For lake trout from western Lake Ontario, mean egg thiamine concentration showed significant annual variability during 1994 to 2003, when the proportion of lake trout at risk of developing EMS based on ED20 ranged between 77 and 100%. Variation in the annual mean egg thiamine concentration for western Lake Ontario lake trout was positively related (p < 0.001, r2 = 0.94) with indices of annual adult alewife biomass. While suggesting the possible involvement of density-dependent changes in alewives, the changes are small relative to egg thiamine concentrations when alewife are not part of the diet and are of insufficient magnitude to allow for natural reproduction by lake trout.

Spatial distribution of deaths due to Alzheimer's disease in the state of São Paulo, Brazil.

PubMed

Almeida, Milena Cristina da Silva; Gomes, Camila de Moraes Santos; Nascimento, Luiz Fernando Costa

2014-01-01

Alzheimer's disease is a common cause of dementia and identifying possible spatial patterns of mortality due to this disease may enable preventive actions. The objective of this study was to identify spatial distribution patterns of mortality due to Alzheimer's disease in the state of São Paulo. Ecological and exploratory study conducted in all municipalities in the state of São Paulo. Data on Alzheimer's disease mortality in the state of São Paulo between 2004 and 2009 were obtained from DATASUS (the Department of Informatics in the Brazilian Ministry of Health). Death rates per 100,000 inhabitants were then calculated and spatial analysis was performed by constructing a death rate map, global Moran index and local Moran index, which were used to obtain the Moran map. The kernel technique was also applied. The Terra View 4.0.0 software was used. 13,030 deaths due to Alzheimer were reported in the state of São Paulo (rate of 5.33 deaths/100,000 inhabitants). São José do Rio Preto, Ribeirão Preto, Bauru and Araçatuba had higher rates. The Moran index was I = 0.085 (P < 0.002). The Moran map identified 42 municipalities that merit intervention and the kernel estimator identified a high density of deaths in the northwestern region of the state. Higher densities of deaths due to Alzheimer were concentrated more to the north and northwest of the state of São Paulo. It was possible to identify municipalities that have priority for interventions to reduce the death rates due to this disease.

Determination and residual characteristic of alkylphenols in household food detergents of Taiwan.

PubMed

Pan, Yi-Ping; Tsai, Shih-Wei

2009-07-01

The non-ionic surfactants are mostly composed of alkylphenols for the ingredients of synthetic food detergents. Due to the ability to mimic hormones, it has been noticed that the exposures of alkylphenols might cause a variety of adverse effects. To assess the associate risks from possible exposures, concentrations of alkylphenols, including 4-nonylphenol (4-NP), technical nonylphenol isomers (t-NP(S)), and 4-tert-octylphenol (4-t-OP), in household food detergents of Taiwan were determined. Gas chromatography with mass spectrometer (GC/MS) was used to analyze alkylphenols in samples. The Taguchi experimental design was utilized to study the possible factors that might affect the residual characteristics of alkylphenols from detergents on dishware and fruits. By the analysis of variance, the orders of importance of different parameters were determined. The results showed that the concentrations of alkylphenols in food detergents ranged from 1.71 x 10(-5) to 2.13 x 10(-3) (APs/detergent, mgg(-1)). For residual characteristics, the cleaning temperature was found to be the only significant factor that will affect the 4-t-OP left on the dishware, while the concentrations of detergents used will affect the left of t-NPs and 4-NP on dishware as well. On the other hand, the varieties of fruits, the concentrations of detergents, and the concentrations of alkylphenols were found to have significant effects for the t-NPs left on fruits. As for the exposure assessments, the maximum dose of APs exposures from the use of household food detergents in Taiwan was also estimated in the study.

Characterization and treatment of dissolved organic matter from oilfield produced waters.

PubMed

Wang, Xiaojing; Goual, Lamia; Colberg, Patricia J S

2012-05-30

Dissolved organic matter (DOM) has been studied intensively in streams, lakes and oceans due to its role in the global carbon cycle and because it is a precursor of carcinogenic disinfection by-products in drinking water; however, relatively little research has been conducted on DOM in oilfield produced waters. In this study, recovery of DOM from two oilfield produced waters was relatively low (~34%), possibly due to the presence of high concentrations of volatile organic compounds (VOCs). A van Krevelen diagram of the extracted DOM suggested the presence of high concentrations of lipids, lignin, and proteins, but low concentrations of condensed hydrocarbons. Most of the compounds in the oilfield DOM contained sulfur in their structures. Fourier transform infrared (FTIR) spectra indicated the presence of methyl groups, amides, carboxylic acids, and aromatic compounds, which is in agreement with results of Fourier transform ion cyclotron resonance (FT-ICR) analysis. Qualitatively, DOM in oilfield produced waters is similar to that reported in oceans and freshwater, except that it contains much more sulfur and is less aromatic. Treatment studies conducted in a fluidized bed reactor suggested that volatilization of organics may be a more important mechanism of DOM removal than microbial degradation. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of chromatographic conditions and plasmid DNA size on the dynamic binding capacity of a monolithic support.

PubMed

Bicho, Diana; Sousa, Ângela; Sousa, Fani; Queiroz, João; Tomaz, Cãndida

2014-09-01

DNA therapies are becoming recognized alternatives for the treatment and prevention of severe pathologies. Although most current trials have used plasmids <10 kbp, in the future larger plasmids would be required. The purpose of this work was to study the chromatographic behavior of nongrafted carbonyldiimidazole monolithic disks using plasmids with different sizes under hydrophobic conditions. Thereunto, the purification of several plasmids was performed. Higher size plasmids needed lower ammonium sulfate concentration, due to the greater number of interactions between the plasmids and monolith. The dynamic binding capacity experiments for the different plasmids revealed a lower capacity for bigger plasmids. It was also verified that the increase of salt concentration from 2.5 to 3 M of ammonium sulfate increased the capacity. At the highest salt concentration, a slight improvement in the capacity using lower flow rate was observed, possibly due to compaction of plasmid molecules and its better organization on the monolith channels. Finally, a low pH also had a positive effect on the capacity. So, this monolithic support proved to be appropriate to purify the supercoiled isoform of different plasmids with different sizes, providing a valuable instrument as a purification technique. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of contamination pathways of phthalates in food products sold on the Belgian market.

PubMed

Van Holderbeke, Mirja; Geerts, Lieve; Vanermen, Guido; Servaes, Kelly; Sioen, Isabelle; De Henauw, Stefaan; Fierens, Tine

2014-10-01

As numerous studies have indicated that food ingestion is the most important exposure pathway to several phthalates, this study aimed to determine possible contamination pathways of phthalates in food products sold on the Belgian market. To do this, concentrations of eight phthalates (dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), benzylbutyl phthalate (BBP), dicyclohexyl phthalate (DCHP), di(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP)) were determined in 591 foods and 30 packaging materials. In general, the four most prominent phthalates in Belgian food products were DEHP, DiBP, DnBP and BBP. Special attention was given to the origin of these phthalates in bread, since high phthalate concentrations (especially DEHP) were determined in this frequently consumed food product. Phthalates seemed to occur in Belgian bread samples due to the use of contaminated ingredients (i.e. use of contaminated flour) as well as due to migration from phthalate containing contact materials used during production (e.g. coated baking trays). Also the results of the conducted concentration profiles of apple, bread, salami and two cheese types revealed the important role of processing - and not packaging - on phthalate contents in foods. Copyright © 2014 Elsevier Inc. All rights reserved.

Endocrine, immune, and behavioral effects of aldicarb (carbamate), atrazine (triazine) and nitrate (fertilizer) mixtures at groundwater concentrations.

PubMed

Porter, W P; Jaeger, J W; Carlson, I H

1999-01-01

This paper describes the results of 5 years of research on interactive effects of mixtures of aldicarb, atrazine, and nitrate on endocrine, immune, and nervous system function. The concentrations of chemicals used were the same order of magnitude as current maximum contaminant levels (MCLs) for all three compounds. Such levels occur in groundwater across the United States. Dosing was through voluntary consumption of drinking water. We used fractional and full factorial designs with center replicates to determine multifactor effects. We used chronic doses in experiments that varied in duration from 22 to 103 days. We tested for changes in thyroid hormone levels, ability to make antibodies to foreign proteins, and aggression in wild deer mice, Peromyscus maniculatus, and white outbred Swiss Webster mice, Mus musculus, ND4 strain. Endocrine, immune, and behavior changes occurred due to doses of mixtures, but rarely due to single compounds at the same concentrations. Immune assay data suggest the possibility of seasonal effects at low doses. We present a multiple-level model to help interpret the data in the context of human health and biological conservation concerns. We discuss six testing deficiencies of currently registered pesticides, and suggest areas of human health concerns if present trends in pesticide use continue.

On-line estimation and detection of abnormal substrate concentrations in WWTPs using a software sensor: a benchmark study.

PubMed

Benazzi, F; Gernaey, K V; Jeppsson, U; Katebi, R

2007-08-01

In this paper, a new approach for on-line monitoring and detection of abnormal readily biodegradable substrate (S(s)) and slowly biodegradable substrate (X(s)) concentrations, for example due to input of toxic loads from the sewer, or due to influent substrate shock load, is proposed. Considering that measurements of S(s) and X(s) concentrations are not available in real wastewater treatment plants, the S(s) / X(s) software sensor can activate an alarm with a response time of about 60 and 90 minutes, respectively, based on the dissolved oxygen measurement. The software sensor implementation is based on an extended Kalman filter observer and disturbances are modelled using fast Fourier transform and spectrum analyses. Three case studies are described. The first one illustrates the fast and accurate convergence of the extended Kalman filter algorithm, which is achieved in less than 2 hours. Furthermore, the difficulties of estimating X(s) when off-line analysis is not available are depicted, and the S(s) / X(s) software sensor performances when no measurements of S(s) and X(s) are available are illustrated. Estimation problems related to the death-regeneration concept of the activated sludge model no.1 and possible application of the software sensor in wastewater monitoring are discussed.

A study of indoor radon, thoron and their exhalation rates in the environment of Fazilka district, Punjab, India

NASA Astrophysics Data System (ADS)

Narang, Saurabh; Kumar, Deepak; Sharma, Dinesh Kumar; Kumar, Ajay

2018-02-01

Over the last few decades, the study of radioactive radon gas has gained huge momentum due to its possible role in health related hazards. In the present work, pin-hole twin chamber single entrance dosimeters have been used for track measurements of radon and thoron. The annual average radon concentration varies from 50.3 to 204 Bq/m3 at all locations. Almost all the values are below the safe range provided by ICRP. Radon concentration is found to be higher in winter as compared to other seasons. Variation of radon with quality of dwellings is also discussed. The values of annual effective dose due to radon and thoron are also well within the range provided by ICRP and WHO. Radon and thoron exhalation rates are measured using SMART RnDuo monitor. The radon mass exhalation rates ranged from 11 to 71 mBq/kg/h while the thoron surface values ranged from 36 to 2048 Bq/m2/h. All the values are on the lower side. A weak correlation is found between radon and thoron concentrations and their exhalation rates. When compared with the values of other parts of northern India, the values of present investigation are on higher side.

Response of Cassava canopy to mid-day pseudo sunrise induced by solar eclipse.

PubMed

Latha, R; Murthy, B S

2013-07-01

Variations in CO(2) concentration over a cassava canopy were measured during a solar eclipse at Thiruvananthapuram, India. The analysis presented attempts to differentiate between the eclipse effect and the possible effect of thick clouds, taking CO(2) as a proxy for photosynthesis. CO(2) and water vapor were measured at a rate of 10 Hz, and radiation at 1 Hz, together with other meteorological parameters. A rapid reduction in CO(2) observed post-peak eclipse, due apparently to intense photosynthesis, appears similar to what happens at daybreak/post-sunrise. The increase in CO(2) (4 ppm) during peak eclipse, with radiation levels falling below the photosynthesis cut-off for cassava, indicates domination of respiration due to the light-limiting conditions.

Response of Cassava canopy to mid-day pseudo sunrise induced by solar eclipse

NASA Astrophysics Data System (ADS)

Latha, R.; Murthy, B. S.

2013-07-01

Variations in CO2 concentration over a cassava canopy were measured during a solar eclipse at Thiruvananthapuram, India. The analysis presented attempts to differentiate between the eclipse effect and the possible effect of thick clouds, taking CO2 as a proxy for photosynthesis. CO2 and water vapor were measured at a rate of 10 Hz, and radiation at 1 Hz, together with other meteorological parameters. A rapid reduction in CO2 observed post-peak eclipse, due apparently to intense photosynthesis, appears similar to what happens at daybreak/post-sunrise. The increase in CO2 (4 ppm) during peak eclipse, with radiation levels falling below the photosynthesis cut-off for cassava, indicates domination of respiration due to the light-limiting conditions.

Can MODIS AOD be employed to derive PM2.5 in Beijing-Tianjin-Hebei over China?

NASA Astrophysics Data System (ADS)

Ma, Xiaoyan; Wang, Jianying; Yu, Fangqun; Jia, Hailing; Hu, Yanan

2016-11-01

The fine particular matter (PM) concentrations in China have increased considerably due to the rapid economic growth and urbanization in the last few decades, especially in the most populated and industrialized regions. Beijing-Tianjin-Hebei is one of the most polluted regions in China, so to monitor the PM2.5 concentrations over this region is quite critical for human health. By making use the new released hourly PM2.5 mass concentration from ground-based observations in Beijing-Tianjin-Hebei over China, and collocated MODIS level 2 AOD data from April 2014 to March 2015, we explored the relation between surface PM2.5 mass concentration and MODIS AOD and possibility to derive the surface PM2.5 from satellite retrieval in the region. Our study show that the relation strongly depend on the seasons due to distinct seasonal characteristics of PM2.5 and AOD, with a relatively better correlation in spring and summertime (correlation coefficient r ranging from 0.52 to 0.79) than autumn and wintertime (r can be low as to 0.23 in site Baoding). Our analysis gave evidence that worse relationship and/or smaller number of sample in wintertime is associated with the significantly high PM2.5 concentration and a lot of missing data occurring in MODIS AOD, implying that current MODIS AOD retrieval scheme does not work very well in highly polluted cases. The derived PM2.5 mass concentration from MODIS AOD in summertime can basically capture the major observed features of the time series and about 20% large bias of the derived values compared to the observation is expected to be reduced if longer time period data is available and used for analysis.

Can MODIS AOD be employed to derive PM2.5 in Beijing-Tianjin-Hebei over China?

NASA Astrophysics Data System (ADS)

Ma, Xiaoyan

2017-04-01

The fine particular matter (PM) concentrations in China have increased considerably due to the rapid economic growth and urbanization in the last few decades, especially in the most populated and industrialized regions. The Beijing-Tianjin-Hebei is one of the most polluted regions in China, so to monitor the PM2.5 concentrations over this region is quite critical for human health. By making use the new released hourly PM2.5 mass concentration from ground-based observations in Beijing-Tianjin-Hebei over China, and the collocated MODIS level 2 AOD data from April 2014 to March 2015, we explored the relation between surface PM2.5 mass concentration and MODIS AOD and possibility to derive the surface PM2.5 from satellite retrieval in the region. Our study show that the relation strongly depend on the seasons due to distinct seasonal characteristics of PM2.5 and AOD, with a relatively better correlation in spring and summertime than autumn and wintertime. Our analysis give an evidence that worse relationship and/or smaller number of sample in wintertime is associated with the significantly high PM2.5 concentration and a lot of missing data occurring in MODIS AOD, implying that current MODIS AOD retrieval scheme does not work very well in highly polluted cases. The derived PM2.5 mass concentration from MODIS AOD in summertime can basically capture the major observed features of the time series and about 20% large bias of the derived values compared to the observation is expected to be reduced once longer time period data is available and used for analysis.

Dose-mortality assessment upon reuse and recycling of industrial sludge.

PubMed

Lin, Kae-Long; Chen, Bor-Yann

2007-09-05

This study provides a novel attempt to put forward, in general toxicological terms, quantitative ranking of toxicity of various sources of sludge for possible reusability in further applications. The high leaching concentrations of copper in printed circuit board (PCB) sludge and chromium in leather sludge apparently exceeded current Taiwan's EPA regulatory thresholds and should be classified as hazardous wastes. Dose-mortality analysis indicated that the toxicity ranking of different sources of sludge was PCB sludge>CaF(2) sludge>leather sludge. PCB sludge was also confirmed as a hazardous waste since the toxicity potency of PCB sludge was nearly identical to CdCl(2). However, leather sludge seemed to be much less toxic than as anticipated, perhaps due to a significant decrease of toxic species bioavailable in the aqueous phase to the reporter bacterium Escherichia coli DH5alpha. For possible reusability of sludge, maximum concentrations allowable to be considered "safe" (ca. EC(100)/100) were 9.68, 42.1 and 176 mgL(-1) for CaF(2) sludge, PCB sludge and leather sludge, respectively.

Forecasting methodologies for Ganoderma spore concentration using combined statistical approaches and model evaluations

NASA Astrophysics Data System (ADS)

Sadyś, Magdalena; Skjøth, Carsten Ambelas; Kennedy, Roy

2016-04-01

High concentration levels of Ganoderma spp. spores were observed in Worcester, UK, during 2006-2010. These basidiospores are known to cause sensitization due to the allergen content and their small dimensions. This enables them to penetrate the lower part of the respiratory tract in humans. Establishment of a link between occurring symptoms of sensitization to Ganoderma spp. and other basidiospores is challenging due to lack of information regarding spore concentration in the air. Hence, aerobiological monitoring should be conducted, and if possible extended with the construction of forecast models. Daily mean concentration of allergenic Ganoderma spp. spores in the atmosphere of Worcester was measured using 7-day volumetric spore sampler through five consecutive years. The relationships between the presence of spores in the air and the weather parameters were examined. Forecast models were constructed for Ganoderma spp. spores using advanced statistical techniques, i.e. multivariate regression trees and artificial neural networks. Dew point temperature along with maximum temperature was the most important factor influencing the presence of spores in the air of Worcester. Based on these two major factors and several others of lesser importance, thresholds for certain levels of fungal spore concentration, i.e. low (0-49 s m-3), moderate (50-99 s m-3), high (100-149 s m-3) and very high (150 < n s m-3), could be designated. Despite some deviation in results obtained by artificial neural networks, authors have achieved a forecasting model, which was accurate (correlation between observed and predicted values varied from r s = 0.57 to r s = 0.68).

Interfacial behavior of polymer electrolytes

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

Kerr, John; Kerr, John B.; Han, Yong Bong

2003-06-03

Evidence is presented concerning the effect of surfaces on the segmental motion of PEO-based polymer electrolytes in lithium batteries. For dry systems with no moisture the effect of surfaces of nano-particle fillers is to inhibit the segmental motion and to reduce the lithium ion transport. These effects also occur at the surfaces in composite electrodes that contain considerable quantities of carbon black nano-particles for electronic connection. The problem of reduced polymer mobility is compounded by the generation of salt concentration gradients within the composite electrode. Highly concentrated polymer electrolytes have reduced transport properties due to the increased ionic cross-linking. Combinedmore » with the interfacial interactions this leads to the generation of low mobility electrolyte layers within the electrode and to loss of capacity and power capability. It is shown that even with planar lithium metal electrodes the concentration gradients can significantly impact the interfacial impedance. The interfacial impedance of lithium/PEO-LiTFSI cells varies depending upon the time elapsed since current was turned off after polarization. The behavior is consistent with relaxation of the salt concentration gradients and indicates that a portion of the interfacial impedance usually attributed to the SEI layer is due to concentrated salt solutions next to the electrode surfaces that are very resistive. These resistive layers may undergo actual phase changes in a non-uniform manner and the possible role of the reduced mobility polymer layers in dendrite initiation and growth is also explored. It is concluded that PEO and ethylene oxide-based polymers are less than ideal with respect to this interfacial behavior.« less

Forecasting methodologies for Ganoderma spore concentration using combined statistical approaches and model evaluations.

PubMed

Sadyś, Magdalena; Skjøth, Carsten Ambelas; Kennedy, Roy

2016-04-01

High concentration levels of Ganoderma spp. spores were observed in Worcester, UK, during 2006-2010. These basidiospores are known to cause sensitization due to the allergen content and their small dimensions. This enables them to penetrate the lower part of the respiratory tract in humans. Establishment of a link between occurring symptoms of sensitization to Ganoderma spp. and other basidiospores is challenging due to lack of information regarding spore concentration in the air. Hence, aerobiological monitoring should be conducted, and if possible extended with the construction of forecast models. Daily mean concentration of allergenic Ganoderma spp. spores in the atmosphere of Worcester was measured using 7-day volumetric spore sampler through five consecutive years. The relationships between the presence of spores in the air and the weather parameters were examined. Forecast models were constructed for Ganoderma spp. spores using advanced statistical techniques, i.e. multivariate regression trees and artificial neural networks. Dew point temperature along with maximum temperature was the most important factor influencing the presence of spores in the air of Worcester. Based on these two major factors and several others of lesser importance, thresholds for certain levels of fungal spore concentration, i.e. low (0-49 s m(-3)), moderate (50-99 s m(-3)), high (100-149 s m(-3)) and very high (150 < n s m(-3)), could be designated. Despite some deviation in results obtained by artificial neural networks, authors have achieved a forecasting model, which was accurate (correlation between observed and predicted values varied from r s = 0.57 to r s = 0.68).

Menopause and age-driven changes in blood level of fat- and water-soluble vitamins.

PubMed

Wiacek, M; Zubrzycki, I Z; Bojke, O; Kim, H-J

2013-12-01

The purpose of this cross-sectional study was to assess the association of the menopausal transition with changes in vitamins. The study group comprised women aged 17-85 years from the Third National Health and Nutrition Examination Survey (NHANES), which was conducted between 1988 and 1994, and from the NHANES surveys conducted between 1999 and 2006. Menopausal status was defined using the time since the last period, < 2, 2-12, and > 12 months, for the pre-, peri-, and postmenopause, respectively. The data-cleaning technique employing serum follicle stimulating hormone activity resulted in pre-, peri- and postmenopausal samples encompassing the following age brackets: 17-50, 42-51, and 46-85 years. Statistical inferences were analyzed using non-parametric techniques. Significant increases in vitamin A and vitamin E concentrations across all phases of the menopausal transition were observed. There was a gradual decrease in the vitamin C concentration across all stages of the menopause but a fairly stable concentration of vitamin B12. There was a statistically significant increase in vitamin D between the pre- and postmenopause. Body mass index correlated negatively with serum vitamin concentration in the pre- and postmenopause. Vitamin A should be supplemented in postmenopausal women to decrease the risk of bone fracture. The daily diet should be supplemented with vitamin B12, to avoid possible neurological symptoms due to vitamin B12 deficiency, and with vitamin D to decrease the risk of developing secondary hyperparathyroidism. Due to an adverse influence on serum vitamin concentration, body mass index should be monitored in pre- and postmenopausal women.

Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning

NASA Technical Reports Server (NTRS)

Cess, R. D.; Hameed, S.; Hogan, J. S.

1980-01-01

Tropospheric ozone and methane might increase in the future as the result of increasing anthropogenic emissions of CO, NOx and CH4 due to fossil fuel burning. Since O3 and CH4 are both greenhouse gases, increases in their concentrations could augment global warming due to larger future amounts of atmospheric CO2. To test this possible climatic impact, a zonal energy-balance climate model has been combined with a vertically-averaged tropospheric chemical model. The latter model includes all relevant chemical reactions which affect species derived from H2O, O2, CH4 and NOx. The climate model correspondingly incorporates changes in the infrared heating of the surface-troposphere system resulting from chemically induced changes in tropospheric ozone and methane. This coupled climate-chemical model indicates that global climate is sensitive to changes in emissions of CO, NOx and CH4, and that future increases in these emissions could enhance global warming due to increasing atmospheric CO2.

Efficient Electrocatalytic Water Oxidation at Neutral and High pH by Adventitious Nickel at Nanomolar Concentrations.

PubMed

Roger, Isolda; Symes, Mark D

2015-11-04

Electrolytic water oxidation using earth-abundant elements is a key challenge in the quest to develop cheap, large surface area arrays for solar-to-hydrogen conversion. There have been numerous studies in this area in recent years, but there remains an imperative to demonstrate that the current densities reported are indeed due to the species under consideration and not due to the presence of adventitious (yet possibly highly active) contaminants at low levels. Herein, we show that adventitious nickel at concentrations as low as 17 nM can act as a water oxidation catalyst in mildly basic aqueous solutions, achieving stable (tens of hours) current densities of 1 mA cm(-2) at overpotentials as low as 540 mV at pH 9.2 and 400 mV at pH 13. This nickel was not added to the electrolysis baths deliberately, but it was found to be present in the electrolytes as an impurity by ICP-MS. The presence of nickel on anodes from extended-time bulk electrolysis experiments was confirmed by XPS. In showing that such low levels of nickel can perform water oxidation at overpotentials comparable to many recently reported water oxidation catalysts, this work serves to raise the burden of proof required of new materials in this field: contamination by adventitious metal ions at trace loadings must be excluded as a possible cause of any observed water oxidation activity.

Stable thermophilic anaerobic digestion of dissolved air flotation (DAF) sludge by co-digestion with swine manure.

PubMed

Creamer, K S; Chen, Y; Williams, C M; Cheng, J J

2010-05-01

Environmentally sound treatment of by-products in a value-adding process is an ongoing challenge in animal agriculture. The sludge produced as a result of the dissolved air flotation (DAF) wastewater treatment process in swine processing facilities is one such low-value residue. The objective of this study was to determine the fundamental performance parameters for thermophilic anaerobic digestion of DAF sludge. Testing in a semi-continuous stirred tank reactor and in batch reactors was conducted to determine the kinetics of degradation and biogas yield. Stable operation could not be achieved using pure DAF sludge as a substrate, possibly due to inhibition by long-chain fatty acids or to nutrient deficiencies. However, in a 1:1 ratio (w/w, dry basis) with swine manure, operation was both stable and productive. In the semi-continuous stirred reactor at 54.5 degrees Celsius, a hydraulic residence time of 10 days, and an organic loading rate of 4.68 gVS/day/L, the methane production rate was 2.19 L/L/day and the specific methane production rate was 0.47 L/gVS (fed). Maximum specific methanogenic activity (SMA) in batch testing was 0.15 mmoles CH(4) h(-1) gVS(-1) at a substrate concentration of 6.9 gVS L(-1). Higher substrate concentrations cause an initial lag in methane production, possibly due to long-chain fatty acid or nitrogen inhibition. Copyright 2009 Elsevier Ltd. All rights reserved.

Evaluation of mine fires due to spontaneous combustion in the mechanized faces of Middle Anatolian Lignite mine (OAL), case studies

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

Gueyagueler, T.; Karaman, H.

1995-12-31

In this paper fires due to spontaneous combustion in Middle Anatolian Lignite mine (OAL) which is the first fully mechanized underground lignite mine in Turkey, are studied. Since the installation of mechanization, due to spontaneous heating, four panel fires namely, AO1, AO2, AO3 and AO4 have broken out. During these fires, the concentrations of carbon monoxide, methane and the velocity of air are measured continuously by the Micro Minos Environmental monitoring system. For each fire, the environment where fire has started is examined and the possible causes of the fire are investigated. Also the precautions taken to extinguish the firemore » at different stages are described and the importance of the early detection of mine fire are discussed together with the limitations of the monitoring system the practical difficulties observed during the fire.« less

Characterization of soil heavy metal contamination and potential health risk in metropolitan region of northern China.

PubMed

Qiao, Min; Cai, Chao; Huang, Yizong; Liu, Yunxia; Lin, Aijun; Zheng, Yuanming

2011-01-01

Soil in metropolitan region suffers great contamination risk due to the rapid urbanization especially in developing countries. Beijing and Tianjin, together with their surrounding regions, form a mega-metropolitan region in northern China. To assess the soil environmental quality, a total of 458 surface soil samples were collected from this area. Concentrations of Cr, Cu, Pb, Zn, As, Cd, and Hg were analyzed and compared to the Chinese environmental quality standards for soil. Multivariate analysis was carried out to identify the possible sources and Geographic Information Systems techniques were applied to visualize the spatial data. It was found that the primary inputs of As were due to pedogenic sources, whereas Hg was mainly of anthropogenic source. Other elements including Cr, Cu, Pb, Zn, and Cd were from both lithogenic and anthropogenic origins. Health risk assessment based on the maximum heavy metal concentration indicated that As derived from sewage irrigation area can result in carcinogenic lifetime risk due to ingestion and/or dermal contact of soil. The potential non-carcinogenic risk for children is significant for Pb and the cumulative effect of multiple metals is of concern for children in the vicinity of mining site. The results increased our knowledge for understanding natural and anthropogenic sources as well as health risk for metals in metropolitan soil.

Suicide in Inmates in Nazis and Soviet Concentration Camps: Historical Overview and Critique

PubMed Central

López-Muñoz, Francisco; Cuerda-Galindo, Esther

2016-01-01

Living conditions in concentration camps were harsh and often inhumane, leading many prisoners to commit suicide. We have reviewed this topic in Nazi concentration camps (KL), Soviet special camps, and gulags, providing some preliminary data for our research. Data show that the incidence of suicide in Nazi KL could be up to 30 times higher than the general population and was also much higher than in Soviet special camps (maybe due to more favorable conditions for prisoners and the abolishment of death penalty), while available data on Soviet gulags are contradictory. However, data interpretation is very controversial, because, for example, the Nazi KL authorities used to cover-up the murder victims as suicides. Most of the suicides were committed in the first years of imprisonment, and the method of suicide most commonly used was hanging, although other methods included cutting blood vessels, poisoning, contact with electrified wire, or starvation. It is possible to differentiate two behaviors when committing suicide; impulsive behavior (contact with electrified barbed wire fences) or premeditated suicide (hanging up or through poison). In Soviet special camps, possible motives for suicides could include feelings of guilt for crimes committed, fear of punishment, and a misguided understanding of honor on the eve of criminal trials. Self-destructive behaviors, such as self-mutilation in gulag camps or prisoners who let themselves die, have been widely reported. Committing suicide in concentration camps was a common practice, although precise data may be impossible to obtain. PMID:27303312

Development of a Low-Cost Spectrophotometric Sensor for ClO2 Gas

NASA Astrophysics Data System (ADS)

Conry, Jessica; Scott, Dane; Apblett, Allen; Materer, Nicholas

2006-04-01

ClO2 is of interest because of it's capability to kill biological hazards such as E. coli and mold. However, ClO2 is a toxic, reactive gas that must be generated at the point-of-use. Gas storage is not possible due to the possibility of an explosion. The need to detect the amount of ClO2 at the point-of-use necessitates a low cost sensor. A low-cost spectrophotometric sensor based on a broad-band light source, a photodiode detector and a band-pass filter is proposed. To verify the design, precise determinations of the gas-phase cross-section and characterization of the optical components are necessary. Known concentrations of ClO2(g) are prepared using the equilibrium relationship between an aqueous solution and the gas phase. The aqueous solutions are obtained by generating the gas via a chemical reaction and passing it through water. The concentrations of the aqueous solutions are then determined by chemical titration and UV-visible absorption measurements. For the solutions, a maximum absorption is observed at 359 nm, and the cross section at this wavelength is determined to be 4.79x10-18cm^2, in agreement with previous observations. Using a broad-band source, the absorption of ClO2 gas is successfully analyzed and concentrations are determined as low as 100 ppm. A more recent prototype based on an UV LED can measure down to concentrations as low as one ppm.

Evolving policies to regulate pollution from animal feeding operations.

PubMed

Centner, T J

2001-11-01

Due to concentrations of animals at large facilities, animal feeding operations (AFOs) have emerged as a major potential source of water pollution. The federal government regulates concentrated animal feeding operations under its point-source pollution permitting regulations. A major determinant of whether an operation must apply for a permit is the number of animals at an individual lot or facility. This paper examines federal mandatory controls and voluntary guidelines that seek to reduce contaminant pollution from AFOs. Land treatment practices are delineated due to their importance in reducing the injurious by-products of agricultural production. An evaluation of proposed revisions to federal regulations on confined animal feeding operations suggests they diverge from their goal of controlling water pollution. Federal regulations focus on the size of operation and amount of manure governed by the permitting process to the exclusion of other criteria related to the impairment of water quality. Given the uncertainties about the amount of pollution from AFOs, lack of enforcement of existing regulations, localization of problems, and possible alternatives for addressing the pollution, more demanding federal regulations may not form an appropriate response.

An overview of health-promoting compounds of broccoli (Brassica oleracea var. italica) and the effect of processing.

PubMed

Mahn, Andrea; Reyes, Alejandro

2012-12-01

Broccoli offers many heath-promoting properties owing to its content of antioxidant and anticarcinogenic compounds. The concentration and bioavailability of polyphenols, glucosinolates, sulforaphane and selenium depend on plant biochemistry, cultivation strategy and type of processing. In this article, the main biochemical properties of broccoli are reviewed regarding their health-promoting effects. Additionally, the way these properties are affected by processing is discussed. Steaming and drying result in an apparent increment of sulforaphane content as well as antioxidant activity, most likely due to an increase of the extractability of antioxidants and sulforaphane. Freezing and boiling diminish polyphenols concentration, mainly due to volatilization and leaching into the cooking water. In view of these results, the optimization of broccoli processing in order to maximize the content of bioactive compounds should be possible. The effect of processing on selenium compounds has been poorly studied so far, and therefore this topic should be investigated in the future. Finally, the effect of operating conditions in different drying processes on the content of bioactive compounds in broccoli should be investigated in a greater depth.

Nitrifying aerobic granular sludge fermentation for releases of carbon source and phosphorus: The role of fermentation pH.

PubMed

Zou, Jinte; Pan, Jiyang; He, Hangtian; Wu, Shuyun; Xiao, Naidong; Ni, Yongjiong; Li, Jun

2018-07-01

The effect of fermentation pH (uncontrolled, 4 and 10) on the releases of carbon source and phosphorus from nitrifying aerobic granular sludge (N-AGS) was investigated. Meanwhile, metal ion concentration and microbial community characterization were explored during N-AGS fermentation. The results indicated that N-AGS fermentation at pH 10 significantly promoted the releases of soluble chemical oxygen demand (SCOD) and total volatile fatty acids (TVFAs). However, SCOD and TVFA released from N-AGS were inhibited at pH 4. Moreover, acidic condition promoted phosphorus release (mainly apatite) from N-AGS during anaerobic fermentation. Nevertheless, alkaline condition failed to increase phosphorus concentration due to the formation of chemical-phosphate precipitates. Compared with the previously reported flocculent sludge fermentation, N-AGS fermentation released more SCOD and TVFAs, possibly due to the greater extracellular polymeric substances content and some hydrolytic-acidogenic bacteria in N-AGS. Therefore, N-AGS alkaline fermentation facilitated the carbon source recovery, while N-AGS acidic fermentation benefited the phosphorus recovery. Copyright © 2018. Published by Elsevier Ltd.

Underground and ground-level particulate matter concentrations in an Italian metro system

NASA Astrophysics Data System (ADS)

Cartenì, Armando; Cascetta, Furio; Campana, Stefano

2015-01-01

All around the world, many studies and experimental results have assessed elevated concentrations of Particulate Matter (PM) in underground metro systems, with non-negligible implications for human health due to protracted exposure to fine particles. Starting from this consideration, an intensive particulate sampling campaign was carried out in January 2014 measuring the PM concentrations in the Naples (Italy) Metro Line 1, both at station platforms and inside trains. Naples Metro Line 1 is about 18 km long, with 17 stations (3 ground-level and 14 below-ground ones). Experimental results show that the average PM10 concentrations measured in the underground station platforms range between 172 and 262 μg/m3 whilst the average PM2.5 concentrations range between 45 and 60 μg/m3. By contrast, in ground-level stations no significant difference between stations platforms and urban environment measurements was observed. Furthermore, a direct correlation between trains passage and PM concentrations was observed, with an increase up to 42% above the average value. This correlation is possibly caused by the re-suspension of the particles due to the turbulence induced by trains. The main original finding was the real-time estimations of PM levels inside the trains travelling both in ground-level and underground sections of Line 1. The results show that high concentrations of both PM10 (average values between 58 μg/m3 and 138 μg/m3) and PM2.5 (average values between 18 μg/m3 and 36 μg/m3) were also measured inside trains. Furthermore, measurements show that windows left open on trains caused the increase in PM concentrations inside trains in the underground section, while in the ground-level section the clean air entering the trains produced an environmental "washing effect". Finally, it was estimated that every passenger spends on average about 70 min per day exposed to high levels of PM.

Embryo-Specific Gene Expression in Microspore-Derived Embryos of Brassica napus. An Interaction between Abscisic Acid and Jasmonic Acid1, 2

PubMed Central

Hays, Dirk B.; Wilen, Ronald W.; Sheng, Chuxing; Moloney, Maurice M.; Pharis, Richard P.

1999-01-01

The induction of napin and oleosin gene expression in Brassica napus microspore-derived embryos (MDEs) was studied to assess the possible interaction between abscisic acid (ABA) and jasmonic acid (JA). Napin and oleosin transcripts were detected sooner following treatment with ABA than JA. Treatment of MDEs with ABA plus JA gave an additive accumulation of both napin and oleosin mRNA, the absolute amount being dependent on the concentration of each hormone. Endogenous ABA levels were reduced by 10-fold after treatment with JA, negating the possibility that the observed additive interaction was due to JA-induced ABA biosynthesis. Also, JA did not significantly increase the uptake of [3H-ABA] from the medium into MDEs. This suggests that the additive interaction was not due to an enhanced carrier-mediated ABA uptake by JA. Finally, when JA was added to MDEs that had been treated with the ABA biosynthesis inhibitor fluridone, napin mRNA did not increase. Based on these results with the MDE system, it is possible that embryos of B. napus use endogenous JA to modulate ABA effects on expression of both napin and oleosin. In addition, JA could play a causal role in the reduction of ABA that occurs during late stages of seed development. PMID:10069845

High concentrations of thiosulfate in scala tympani perilymph after systemic administration in the guinea pig.

PubMed

Pierre, Pernilla Videhult; Engmér, Cecilia; Wallin, Inger; Laurell, Göran; Ehrsson, Hans

2009-02-01

High concentrations of the antioxidant thiosulfate reach scala tympani perilymph after i.v. administration in the guinea pig. Thiosulfate concentrations in perilymph remain elevated longer than in blood. This warrants further studies on the possibility of obtaining otoprotection by thiosulfate administration several hours before that of cisplatin without compromising the anticancer effect caused by cisplatin inactivation in the blood compartment. Thiosulfate may reduce cisplatin-induced ototoxicity, presumably by oxidative stress relief and formation of inactivate platinum complexes. This study aimed to explore to what extent thiosulfate reaches scala tympani perilymph after systemic administration in the guinea pig. Scala tympani perilymph (1 microl) was aspirated from the basal turn of each cochlea up to 3 h after thiosulfate administration (103 mg/kg b.w., i.v.). Blood samples were also taken. Thiosulfate was quantified by HPLC and fluorescence detection. Substantial thiosulfate concentrations were found in perilymph. The area under the concentration-time curve for thiosulfate in perilymph and blood was 3100 microMxmin and 6300 microMxmin, respectively. The highest thiosulfate concentrations in perilymph were found at the first sampling at about 10 min. Due to a more rapid elimination from blood, perilymph concentrations exceeded those of blood towards the end of the experiment.

Widespread occurrence and seasonal variation of pharmaceuticals in surface waters and municipal wastewater treatment plants in central Finland.

PubMed

Lindholm-Lehto, Petra C; Ahkola, Heidi S J; Knuutinen, Juha S; Herve, Sirpa H

2016-04-01

The presence of five selected pharmaceuticals, consisting of four anti-inflammatory drugs, diclofenac, ibuprofen, ketoprofen, naproxen, and an antiepileptic drug carbamazepine, was determined at four municipal wastewater treatment plants (WWTPs) and in the receiving waterway in central Finland. The samples were taken from influents and effluents of the WWTPs and from surface water of six locations along the water way, including northern Lake Päijänne. In addition, seasonal variation in the area was determined by comparing the concentrations in the winter and summer. The samples were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The concentrations in the influents and effluents ranged from hundreds of nanogram per liter to microgram per liter while ranged from tens of nanogram per liter in northern parts of the waterway to hundreds of nanogram per liter in northern Lake Päijänne near the city area. In addition, the concentrations were higher in the winter compared to summer time in surface water due to decreased temperature and solar irradiation. On the other hand, higher concentrations of ibuprofen, ketoprofen, and naproxen were found in summer at the WWTPs, possibly due to seasonal variations in consumption. In conclusion, there are considerable amounts of pharmaceuticals not only in influents and effluents of the WWTPs but also in lake water along the waterway and in northern Lake Päijänne.

Optical and Physical Investigations of Lanthanum Bismuth Borate glasses doped with Ho2O3

NASA Astrophysics Data System (ADS)

Ramesh, P.; Jagannath, G.; Eraiah, B.; Kokila, M. K.

2018-02-01

Holmium doped 10La2O3-15Bi2O3-(75-x) B2O3 (Ho3+: LBB) glasses have been prepared by melt quench technique and the impact of holmium ions concentration on optical and physical properties of present glasses have been examined. Ho3+ dependent density, molar volume, refractive index, rare earth ion concentration, polaron radius, inter ionic distance, field strength and energy band gap are calculated and tabulated. Amorphous nature of the all glasses has been confirmed by XRD patterns. The room temperature (RT) Uv-Vis absorption spectrum doped with 1 mol% of Ho2O3 exhibit eight prominent bands centred at 895, 641, 537, 486, 472, 467, 451 and 416 due to transition between ground state to various excited states. The results show that, the density is increases and molar volume of the glasses is decreases with an increase in Ho2O3 concentration and consequently generate more non-bridging oxygen (NBOs) in the glass matrix. The Urbach energy is increases with holmium concentration which exemplifies the degree of disorder present in the LBB glasses. The considerable increase in field strength observed in present glasses is attributed to occurrence of strong bridge between Ho3+ and B- ions and this strong bridge is possibly due to the displacement between Ho3+ and oxygen atoms which are generated from the conversion BO3-BO4 units.

Mercury Exposure in Humboldt (Spheniscus humboldti) and Chinstrap (Pygoscelis antarcticus) Penguins Throughout the Chilean Coast and Antarctica.

PubMed

Álvarez-Varas, Rocío; Morales-Moraga, David; González-Acuña, Daniel; Klarian, Sebastián A; Vianna, Juliana A

2018-07-01

Penguins are reliable sentinels for environmental assessments of mercury (Hg) due to their longevity, abundance, high trophic level, and relatively small foraging areas. We analyzed Hg concentrations from blood and feathers of adult Humboldt penguins (Spheniscus humboldti) and feathers of chinstrap penguins (Pygoscelis antarcticus) from different reproductive colonies with variable degrees of urbanization and industrialization along the Chilean and Antarctic coasts. We evaluated Hg concentration differences between species, sexes (Humboldt penguins), and localities. Our results showed significantly greater levels in Humboldt penguins than in chinstrap penguins and nonsignificant differences between sexes among Humboldts. Penguin Hg concentrations showed a latitudinal pattern, with greater values of the metal at lower latitudes, independent of the species. Both studied penguin species showed elevated Hg concentrations compared to their congeners, highlighting the necessity to investigate potential negative effects on their populations. Although differences between species are possibly due to variation in diet and trophic level, our results suggest an important effect of the degree of Hg pollution adjacent to foraging areas. Further research on Hg content in prey species and environmental samples, together with a larger overall sample size, and investigation on penguin's diet and trophic level are needed to elucidate Hg bioavailability in each location and the role of local Hg pollution levels. Likewise, it is important to monitor Hg and other heavy metals of ecotoxicological importance in penguin populations in vulnerable regions of Chile.

Environmentally relevant concentrations of nitrate increase plasma testosterone concentrations in female American alligators (Alligator mississippiensis).

PubMed

Hamlin, Heather J; Edwards, Thea M; McCoy, Jessica; Cruze, Lori; Guillette, Louis J

2016-11-01

Anthropogenic nitrogen is a ubiquitous environmental contaminant that is contributing to the degradation of freshwater, estuarine, and coastal ecosystems worldwide. The effects of environmental nitrate, a principal form of nitrogen, on the health of aquatic life is of increasing concern. We exposed female American alligators to three concentrations of nitrate (0.7, 10 and 100mg/L NO 3 -N) for a duration of five weeks and five months from hatch. We assessed growth, plasma sex steroid and thyroid hormone concentrations, and transcription levels of key genes involved in steroidogenesis (StAR, 3β-HSD, and P450 scc ) and hepatic clearance (Cyp1a, Cyp3a). Exposure to 100mg/L NO 3 -N for both five weeks and five months resulted in significantly increased plasma testosterone (T) concentrations compared with alligators in the reference treatment. No differences in 17β-estradiol, progesterone, or thyroid hormones were observed, nor were there differences in alligator weight or the mRNA abundance of steroidogenic or hepatic genes. Plasma and urinary nitrate concentrations increased with increasing nitrate treatment levels, although relative plasma concentrations of nitrate were significantly lower in five month, versus five week old animals, possibly due to improved kidney function in older animals. These results indicate that environmentally relevant concentrations of nitrate can increase circulating concentrations of T in young female alligators. Copyright © 2016 Elsevier Inc. All rights reserved.

SERPINE 1 Links Obesity and Diabetes: A Pilot Study

PubMed Central

Kaur, Punit; Reis, Michael D.; Couchman, Glen R.; Forjuoh, Samuel N.; Greene, John F.; Asea, Alexzander

2010-01-01

In the past decade there has been a dramatic increase in the number of Americans considered obese. Over this same period, the number of individuals diagnosed with diabetes has increased by over 40%. Interestingly, in a great number of cases individuals considered obese develop diabetes later on. Although a link between obesity and diabetes has been suggested, conclusive scientific evidence is thus far just beginning to emerge. The present pilot study is designed to identify a possible link between obesity and diabetes. The plasma proteome is a desirable biological sample due to their accessibility and representative complexity due, in part, to the wide dynamic range of protein concentrations, which lead to the discovery of new protein markers. Here we present the results for the specific depletion of 14 high-abundant proteins from the plasma samples of obese and diabetic patients. Comparative proteomic profiling of plasma from individuals with either diabetes or obesity and individuals with both obesity and diabetes revealed SERPINE 1 as a possible candidate protein of interest, which might be a link between obesity and diabetes. PMID:21113241

SERPINE 1 Links Obesity and Diabetes: A Pilot Study.

PubMed

Kaur, Punit; Reis, Michael D; Couchman, Glen R; Forjuoh, Samuel N; Greene, John F; Asea, Alexzander

2010-06-01

In the past decade there has been a dramatic increase in the number of Americans considered obese. Over this same period, the number of individuals diagnosed with diabetes has increased by over 40%. Interestingly, in a great number of cases individuals considered obese develop diabetes later on. Although a link between obesity and diabetes has been suggested, conclusive scientific evidence is thus far just beginning to emerge. The present pilot study is designed to identify a possible link between obesity and diabetes. The plasma proteome is a desirable biological sample due to their accessibility and representative complexity due, in part, to the wide dynamic range of protein concentrations, which lead to the discovery of new protein markers. Here we present the results for the specific depletion of 14 high-abundant proteins from the plasma samples of obese and diabetic patients. Comparative proteomic profiling of plasma from individuals with either diabetes or obesity and individuals with both obesity and diabetes revealed SERPINE 1 as a possible candidate protein of interest, which might be a link between obesity and diabetes.

Immunochemical study of uroporphyrinogen decarboxylase in a patient with mild hepatoerythropoietic porphyria.

PubMed Central

Fujita, H; Sassa, S; Toback, A C; Kappas, A

1987-01-01

Hepatoerythropoietic porphyria (HEP) is due to a marked deficiency of uroporphyrinogen (URO) decarboxylase, a cytosolic enzyme in the heme biosynthetic pathway. Using a radioimmunoassay method, we determined the concentration of URO decarboxylase protein in erythrocytes from a patient with mild HEP and found that the enzyme protein concentration had markedly decreased to less than 7% of the normal controls. This finding, however, was in contrast to the enzyme activity in the patient's erythrocytes, which was 16% of normal control levels and different from previously reported HEP cases in that erythrocytes in our patient contained disproportionately elevated URO decarboxylase activity in comparison to its immunoreactive material. Our findings suggests the possibility of a mutant isozyme in this patient that is not immunoreactive with an antibody raised against the normal enzyme. PMID:3571497

The feasibility of physiologically based pharmacokinetic modeling in forensic medicine illustrated by the example of morphine.

PubMed

Schaefer, Nadine; Moj, Daniel; Lehr, Thorsten; Schmidt, Peter H; Ramsthaler, Frank

2018-03-01

In forensic medicine, expert opinion is often required concerning dose and time of intake of a substance, especially in the context of fatal intoxications. In the present case, a 98-year-old man died 4 days after admission to a hospital due to a femur neck fracture following a domestic fall in his retirement home. As he had obtained high morphine doses in the context of palliative therapy and a confusion of his supplemental magnesium tablets with a diuretic by the care retirement home was suspected by the relatives, a comprehensive postmortem examination was performed. Forensic toxicological GC- and LC-MS analyses revealed, besides propofol, ketamine, and a metamizole metabolite in blood and urine, toxic blood morphine concentrations of approximately 3 mg/l in femoral and 5 mg/l in heart blood as well as 2, 7, and 10 mg/kg morphine in brain, liver, and lung, respectively. A physiologically based pharmacokinetic (PBPK) model was developed and applied to examine whether the morphine concentrations were (i) in agreement with the morphine doses documented in the clinical records or (ii) due to an excessive morphine administration. PBPK model simulations argue against an overdosing of morphine. The immediate cause of death was respiratory and cardiovascular failure due to pneumonia following a fall, femur neck fracture, and immobilization accompanied by a high and probably toxic concentration of morphine, attributable to the administration under palliative care conditions. The presented case indicates that PBPK modeling can be a useful tool in forensic medicine, especially in question of a possible drug overdosing.

Surface ozone characterization at Larsemann Hills and Maitri, Antarctica.

PubMed

Ali, Kaushar; Trivedi, D K; Sahu, S K

2017-04-15

Data are analyzed in terms of daily average ozone, its diurnal variation and its relation with meteorological parameters like dry bulb temperature (T), wet bulb temperature (T w ), atmospheric pressure and wind speed based on measurement of these parameters at two Indian Antarctic stations (Larsemann Hills, and Maitri) during 28th Indian Scientific Expedition of Antarctica (ISEA) organized during Antarctic summer of the year 2008-09. The work has been carried out to investigate summer time ozone level and its day-to-day and diurnal variability at these coastal locations and to highlight possible mechanism of ozone production and destruction. The result of the analysis indicates that daily average ozone concentration at Larsemann Hills varied from ~13 and ~20ppb with overall average value of ~16ppb and at Maitri, it varied from ~16 and ~21ppb with overall average value of ~18ppb. Photochemistry is found to partially contribute occasionally to the surface layer ozone at both the stations. Lower concentration of ozone at Maitri during beginning of the observational days may be due to destruction of ozone through activated halogens, whereas higher ozone on latter days may be due to photochemistry and advective transport from east to south-east areas. Ozone concentration during blizzard episodes at both the stations is reduced due to slow photochemical production of ozone, its photochemical removal and removal through deposition of ozone molecules on precipitation particles. Diurnal variation of ozone at Larsemann Hills and Maitri has been found to be absent. Copyright © 2017 Elsevier B.V. All rights reserved.

78 FR 39190 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-01

... could lead to a local stress concentration resulting in possible reduction of the fatigue life of the... lead to a local stress concentration which may reduce the fatigue life of the jack fitting, possibly... could lead to a local stress concentration resulting in possible reduction of the fatigue life of the...

Tityus bahiensis scorpion venom injected to dams during pregnancy affects some cytokines of fetuses.

PubMed

Dorce, Ana L C; Frare, Eduardo O; Paulo, Maria E F V; Dorce, Valquiria A C; Nencioni, Ana L A

2015-09-01

Due to the high incidence of scorpion stings in Brazil, pregnant women are among the possible victims. Cytokines are important during the pregnancy, and scorpion venoms can change their release. We evaluated the levels of some cytokines in the fetuses after the treatment of pregnant rats with the Tityus bahiensis scorpion venom. The concentration of some of them is altered and can be responsible for the effects previously observed on innate reflexes, and the physical and behavioral development of the offspring. Copyright © 2015 Elsevier Ltd. All rights reserved.

Xylan - A potential contaminant for lunar samples and Antarctic meteorites

NASA Astrophysics Data System (ADS)

Wright, I. P.; Russell, S. S.; Boyd, S. R.; Meyer, C.; Pillinger, C. T.

The possibility that lunar samples have been contaminated by the proprietary lubricant paint known as Xylan, which has been applied to screw threads in dry-N sample processing cabinets at NASA JSC, is considered. From a sample analysis using sealed-tube and stepped combustion, it is argued that the unexpectedly high concentration of organic materials found in EET A79001 is not due to Xylan contamination. It is considered unlikely that previous C and N analyses of lunar samples have been affected by the introduction of Xylan.

An Acute Ocfentanil Fatality: A Case Report with Postmortem Concentrations.

PubMed

Dussy, F E; Hangartner, S; Hamberg, C; Berchtold, C; Scherer, U; Schlotterbeck, G; Wyler, D; Briellmann, T A

2016-11-01

A 24-year-old man known to consume illegal drugs was found dead in his apartment. A reclosable plastic zipper bag containing several hundred milligrams of a brown powder was found close to the dead body and the first assumption of the investigators was death due to heroin intoxication. Therefore, a legal autopsy was ordered. The following toxicological analysis revealed ocfentanil in urine and in the brown powder. Four different approaches for the determination of the ocfentanil concentrations in peripheral whole blood are described. Enrichment of ocfentanil from the powder was realized. With this reference, it was possible to determine the ocfentanil concentration in the seized powder to be 0.91%. Concentrations of ocfentanil were also determined in the sampled body fluids using the standard addition procedure. In peripheral blood 9.1 µg/L, in heart blood 27.9 µg/L and in urine 480 µg/L were measured. In addition, the antidepressant citalopram, the neuroleptic quetiapine and cannabinoids were found in urine and subsequently quantified in peripheral blood. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Alteration of chaotic advection in blood flow around partial blockage zone: Role of hematocrit concentration

NASA Astrophysics Data System (ADS)

Maiti, Soumyabrata; Chaudhury, Kaustav; DasGupta, Debabrata; Chakraborty, Suman

2013-01-01

Spatial distributions of particles carried by blood exhibit complex filamentary pattern under the combined effects of geometrical irregularities of the blood vessels and pulsating pumping by the heart. This signifies the existence of so called chaotic advection. In the present article, we argue that the understanding of such pathologically triggered chaotic advection is incomplete without giving due consideration to a major constituent of blood: abundant presence of red blood cells quantified by the hematocrit (HCT) concentration. We show that the hematocrit concentration in blood cells can alter the filamentary structures of the spatial distribution of advected particles in an intriguing manner. Our results reveal that there primarily are two major impacts of HCT concentrations towards dictating the chaotic dynamics of blood flow: changing the zone of influence of chaotic mixing and determining the enhancement of residence time of the advected particles away from the wall. This, in turn, may alter the extent of activation of platelets or other reactive biological entities, bearing immense consequence towards dictating the biophysical mechanisms behind possible life-threatening diseases originating in the circulatory system.

Anodic stripping voltammetry enhancement by redox magnetohydrodynamics.

PubMed

Clark, Emily A; Fritsch, Ingrid

2004-04-15

The effect of an external magnetic field on linear scan anodic stripping voltammetry (ASV) in solutions of 10(-6)-10(-7) M concentrations of lead, cadmium, and copper at mercury films on glassy carbon electrodes has been investigated. A high concentration of Hg(2+) was added to the analyte solution to induce a large cathodic current during the deposition step. Therefore, a large Lorentz force from the net flux of charge through the magnetic field resulted in convection due to magnetohydrodynamics. The faster delivery of analytes to the mercury film electrode during deposition caused an increase in the anodic stripping peaks. The effect of varying Hg(2+) concentrations (0-60 mM) and magnetic field strengths (0-1.77 T) on the enhancement of the stripping peaks was investigated. Enhancements as large as 129% for peak currents and 167% for peak areas were observed. An enhancement of approximately 100% was observed when 60 mM Fe(3+) replaced high concentrations of Hg(2+). This method of convection exhibits promise for small-volume ASV analysis with possible improved limits of detection and decreased preconcentration times.

Is plasma GABA level a biomarker of Post-Traumatic Stress Disorder (PTSD) severity? A preliminary study.

PubMed

Trousselard, Marion; Lefebvre, Bertrand; Caillet, Lionel; Andruetan, Yann; de Montleau, Franck; Denis, Josiane; Canini, Frédéric

2016-07-30

An increased reactivity to the environment is observed in Post-Traumatic Stress Disorder (PTSD). It would be related to impairment of the Gamma Amino Butyric Acid (GABA) neurotransmission. The study aimed to evaluate plasma GABA concentration as a candidate for PTSD severity biomarker. This hypothesis was studied in 17 PTSD patients and 17 healthy Controls using classic and emotional Stroop paradigms. Plasma GABA concentrations were assessed before and after both Stroop tests to evaluate GABA basal tone and GABA reactivity (change in GABAp), respectively. During baseline, PTSD had lower plasma GABA concentrations than the Controls. After the Stroop conflicts GABA reactivity was also lower in PTSD than in the Controls. The GABA baseline tone was negatively correlated with the severity of the PTSD symptoms. This relation was only marginally observed for GABA reactivity. The results produced a trend due to the small size of the sample compared to the number of statistical results given. Altogether, the reduced GABA concentration observed in PTSD could be considered as a possible biomarker for PTSD severity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effect of Diffusion Limitations on Multianalyte Determination from Biased Biosensor Response

PubMed Central

Baronas, Romas; Kulys, Juozas; Lančinskas, Algirdas; Žilinskas, Antanas

2014-01-01

The optimization-based quantitative determination of multianalyte concentrations from biased biosensor responses is investigated under internal and external diffusion-limited conditions. A computational model of a biocatalytic amperometric biosensor utilizing a mono-enzyme-catalyzed (nonspecific) competitive conversion of two substrates was used to generate pseudo-experimental responses to mixtures of compounds. The influence of possible perturbations of the biosensor signal, due to a white noise- and temperature-induced trend, on the precision of the concentration determination has been investigated for different configurations of the biosensor operation. The optimization method was found to be suitable and accurate enough for the quantitative determination of the concentrations of the compounds from a given biosensor transient response. The computational experiments showed a complex dependence of the precision of the concentration estimation on the relative thickness of the outer diffusion layer, as well as on whether the biosensor operates under diffusion- or kinetics-limited conditions. When the biosensor response is affected by the induced exponential trend, the duration of the biosensor action can be optimized for increasing the accuracy of the quantitative analysis. PMID:24608006

Topological phase transitions of (BixSb1-x)2Se3 alloys by density functional theory.

PubMed

Abdalla, L B; Padilha José, E; Schmidt, T M; Miwa, R H; Fazzio, A

2015-07-01

We have performed an ab initio total energy investigation of the topological phase transition, and the electronic properties of topologically protected surface states of (BixSb1-x)2Se3 alloys. In order to provide an accurate alloy concentration for the phase transition, we have considered the special quasirandom structures to describe the alloy system. The trivial → topological transition concentration was obtained by (i) the calculation of the band gap closing as a function of Bi concentration (x), and (ii) the calculation of the Z2 topological invariant number. We show that there is a topological phase transition, for x around 0.4, verified for both procedures (i) and (ii). We also show that in the concentration range 0.4 < x < 0.7, the alloy does not present any other band at the Fermi level besides the Dirac cone, where the Dirac point is far from the bulk states. This indicates that a possible suppression of the scattering process due to bulk states will occur.

[EXTRINSIC AND INTRINSIC FACTORS FOR FALLS THAT CAUSED HIP FRACTURE].

PubMed

Tsur, Atzmon; Shakeer, Nael; Segal, Zvi; Itah, Dorit; Eluz, Dana

2017-05-01

Among the reasons described as possibly causing falls in older and elderly people are extrinsic factors such as bumping into objects, slipping on a wet floor, etc., and intrinsic factors - those that occur suddenly without warning. To investigate the connection between the reasons for falls, extrinsic or intrinsic and different medical and nonmedical factors. The survey included 82 people, 53 women and 29 men, who fell and broke their hip, underwent surgery, and were treated at the Rehabilitation Department. Data showed that 39 people fell due to extrinsic factors and 43 due to intrinsic reasons. We examined the correlation with several factors, both medical and non-medical, that may have influenced the scenario of each group. Falls due to extrinsic reasons took place at all hours of the day and night, mainly in people who were alone and who wore shoes or sandals at the time of the fall and who either suffered from slight or no disturbances in attention and concentration. Falls due to intrinsic reasons occurred mainly during rest or sleep hours, in people who walked barefoot or with socks or slippers and who suffered moderate or severe disturbances in attention and concentration. Although the differences in the extrinsic vs. intrinsic reasons for falls that led to broken hips were fairly clear, it would be difficult to recommend new tools for prevention of this phenomenon. Trying to predict an infrequent future event such as a traumatic fall is inherently difficult.

Changes in patterns of persistent halogenated compounds through a pelagic food web in the Baltic Sea.

PubMed

Stephansen, Diana A; Svendsen, Tore C; Vorkamp, Katrin; Frier, Jens-Ole

2012-02-01

The concentrations and patterns of persistent halogenated compounds (PHCs), including polychlorinated biphenyls (PCBs), DDT, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB) and polybrominated diphenyl ethers (PBDEs) were examined in a pelagic food web from the southern Baltic Sea consisting of sediment, zooplankton, sprat, Atlantic salmon and anadromous brown trout. Lipid-normalized concentrations generally increased from low trophic levels to high trophic levels, with the exception of HCHs. Due to high concentrations of PBDEs in some zooplankton samples, biomagnification of BDE-47 was only observed for salmon/sprat and trout/sprat. Sprat collected individually and from salmon stomach had significantly different lipid-normalized concentrations and varied in their PHC pattern as well, possibly indicating a large natural variation within the Baltic Sea. The highest lipid-normalized concentrations were found in brown trout. Salmon and brown trout were similar in their PHC pattern suggesting similar food sources. Variation in PHC patterns among trophic levels was not smaller than that among geographically distinct locations, confirming the importance of comparable trophic levels for the assessment of PHC patterns, e.g. for tracing migratory fish. Copyright © 2011 Elsevier Ltd. All rights reserved.

Monitoring and predicting the fecal indicator bacteria concentrations from agricultural, mixed land use and urban stormwater runoff.

PubMed

Paule-Mercado, M A; Ventura, J S; Memon, S A; Jahng, D; Kang, J-H; Lee, C-H

2016-04-15

While the urban runoff are increasingly being studied as a source of fecal indicator bacteria (FIB), less is known about the occurrence of FIB in watershed with mixed land use and ongoing land use and land cover (LULC) change. In this study, Escherichia coli (EC) and fecal streptococcus (FS) were monitored from 2012 to 2013 in agricultural, mixed and urban LULC and analyzed according to the most probable number (MPN). Pearson correlation was used to determine the relationship between FIB and environmental parameters (physicochemical and hydrometeorological). Multiple linear regressions (MLR) were used to identify the significant parameters that affect the FIB concentrations and to predict the response of FIB in LULC change. Overall, the FIB concentrations were higher in urban LULC (EC=3.33-7.39; FS=3.30-7.36log10MPN/100mL) possibly because of runoff from commercial market and 100% impervious cover (IC). Also, during early-summer season; this reflects a greater persistence and growth rate of FIB in a warmer environment. During intra-event, however, the FIB concentrations varied according to site condition. Anthropogenic activities and IC influenced the correlation between the FIB concentrations and environmental parameters. Stormwater temperature (TEMP), turbidity, and TSS positively correlated with the FIB concentrations (p>0.01), since IC increased, implying an accumulation of bacterial sources in urban activities. TEMP, BOD5, turbidity, TSS, and antecedent dry days (ADD) were the most significant explanatory variables for FIB as determined in MLR, possibly because they promoted the FIB growth and survival. The model confirmed the FIB concentrations: EC (R(2)=0.71-0.85; NSE=0.72-0.86) and FS (R(2)=0.65-0.83; NSE=0.66-0.84) are predicted to increase due to urbanization. Therefore, these findings will help in stormwater monitoring strategies, designing the best management practice for FIB removal and as input data for stormwater models. Copyright © 2016 Elsevier B.V. All rights reserved.

Monitoring marine recreational water quality using multiple microbial indicators in an urban tropical environment

PubMed Central

Shibata, Tomoyuki; Solo-Gabriele, Helena M.; Fleming, Lora E.; Elmir, Samir

2008-01-01

The microbial water quality at two beaches, Hobie Beach and Crandon Beach, in Miami-Dade County, Florida, USA was measured using multiple microbial indicators for the purpose of evaluating correlations between microbes and for identifying possible sources of contamination. The indicator microbes chosen for this study (enterococci, Escherichia coli, fecal coliform, total coliform and C. perfringens) were evaluated through three different sampling efforts. These efforts included daily measurements at four locations during a wet season month and a dry season month, spatially intensive water sampling during low- and high-tide periods, and a sand sampling effort. Results indicated that concentrations did not vary in a consistent fashion between one indicator microbe and another. Daily water quality frequently exceeded guideline levels at Hobie Beach for all indicator microbes except for fecal coliform, which never exceeded the guideline. Except for total coliform, the concentrations of microbes did not change significantly between seasons in spite of the fact that the physical–chemical parameters (rainfall, temperature, pH, and salinity) changed significantly between the two monitoring periods. Spatially intense water sampling showed that the concentrations of microbes were significantly different with distance from the shoreline. The highest concentrations were observed at shoreline points and decreased at offshore points. Furthermore, the highest concentrations of indicator microbe concentrations were observed at high tide, when the wash zone area of the beach was submerged. Beach sands within the wash zone tested positive for all indicator microbes, thereby suggesting that this zone may serve as the source of indicator microbes. Ultimate sources of indicator microbes to this zone may include humans, animals, and possibly the survival and regrowth of indicator microbes due to the unique environmental conditions found within this zone. Overall, the results of this study indicated that the concentrations of indicator microbes do not necessarily correlate with one another. Exceedence of water quality guidelines, and thus the frequency of beach advisories, depends upon which indicator microbe is chosen. PMID:15261551

Developing a Metal Proxy for the Rise of Early Terrestrial Life

NASA Astrophysics Data System (ADS)

Rochelle, S. P.; Anbar, A. D.; Hartnett, H. E.; Romaniello, S. J.; Poret-Peterson, A. T.

2015-12-01

Previous work has shown that the presence of biological soil crusts (BSCs) may affect the concentrations of uranium and other transition metals by influencing metal dissolution, solubility, and transport.(1) These effects may provide a proxy for the presence of microbial mat communities in paleosols, possibly constraining the timing of the rise of early terrestrial ecosystems. Thus, in an effort to uncover possible biosignatures, this study examines metal abundances in modern desert BSCs as a possible analogue for early terrestrial life.We present results from a preliminary study comparing crusted and uncrusted soils from a low-desert site near Casa Grande, Arizona. Seventeen 5-cm soil cores were collected and the bulk elemental composition of the top 1 cm of crusted (9 samples) and non-crusted (8 samples) soils were analyzed by quadrupole ICP-MS with a typical measurement precision between 2-5%. Metal concentrations were normalized to aluminum (Al) to minimize dilution effects due to variations in carbonate and quartz content.Although the mean concentrations of nearly all elements were similar in crusted and uncrusted sites, the variability in the normalized concentrations of some of the elements, such as uranium, were different between crusted and uncrusted sites. The average U/Al ratio at the crusted site was 25 ± 1 μg U/ g Al and the average U/Al ratio at the uncrusted site was 27 ± 4 µg U/ g Al. Bartlett's and Levene's tests were used to confirm that the U/Al ratio was significantly more variable in the uncrusted sites as compared to the crusted sites. Iron (Fe), vanadium (V) and cesium (Cs) showed a similar pattern which was significant under Bartlett's but not Levene's test.As U, Fe, and V solubility and transport are redox-sensitive, we hypothesize that their aqueous mobility could have been impacted by diurnal redox swings in the photosynthetic crusts, possibly resulting in the homogenization of local cm-scale variations in background soil concentrations. Future work will test this hypothesis by 1) analyzing samples from a wider range of sites to determine if this pattern is robust and 2) measuring 238U/235U ratios throughout the crust profile to determine if there is evidence for redox-dependent cycling and fractionation of U within modern BSCs.(1) Beraldi-Campesi, H. et al. (2009) Geobiology, 7:348-359.

Study of iron oxide nanoparticles in soil for remediation of arsenic

NASA Astrophysics Data System (ADS)

Shipley, Heather J.; Engates, Karen E.; Guettner, Allison M.

2011-06-01

There is a growing interest in the use of nanoparticles for environmental applications due to their unique physical and chemical properties. One possible application is the removal of contaminants from water. In this study, the use of iron oxide nanoparticles (19.3 nm magnetite and 37.0 nm hematite) were examined to remove arsenate and arsenite through column studies. The columns contained 1.5 or 15 wt% iron oxide nanoparticles and soil. Arsenic experiments were conducted with 1.5 wt% iron oxides at 1.5 and 6 mL/h with initial arsenate and arsenite concentrations of 100 μg/L. Arsenic release occurred after 400 PV, and 100% release was reached. A long-term study was conducted with 15 wt% magnetite nanoparticles in soil at 0.3 mL/h with an initial arsenate concentration of 100 μg/L. A negligible arsenate concentration occurred for 3559.6 pore volumes (PVs) (132.1 d). Eventually, the arsenate concentration reached about 20% after 9884.1 PV (207.9 d). A retardation factor of about 6742 was calculated indicating strong adsorption of arsenic to the magnetite nanoparticles in the column. Also, increased adsorption was observed after flow interruption. Other experiments showed that arsenic and 12 other metals (V, Cr, Co, Mn, Se, Mo, Cd, Pb, Sb, Tl, Th, U) could be simultaneously removed by the iron oxide nanoparticles in soil. Effluent concentrations were less than 10% for six out of the 12 metals. Desorption experiment showed partial irreversible sorption of arsenic to the iron oxide nanoparticle surface. Strong adsorption, large retardation factor, and resistant desorption suggest that magnetite and hematite nanoparticles have the potential to be used to remove arsenic in sandy soil possibly through in situ techniques.

Chemical characterization and ecotoxicity of three soil foaming agents used in mechanized tunneling.

PubMed

Baderna, Diego; Lomazzi, Eleonora; Passoni, Alice; Pogliaghi, Alberto; Petoumenou, Maria Ifigeneia; Bagnati, Renzo; Lodi, Marco; Viarengo, Aldo; Sforzini, Susanna; Benfenati, Emilio; Fanelli, Roberto

2015-10-15

The construction of tunnels and rocks with mechanized drills produces several tons of rocky debris that are today recycled as construction material or as soil replacement for covering rocky areas. The lack of accurate information about the environmental impact of these excavated rocks and foaming agents added during the excavation process has aroused increasing concern for ecosystems and human health. The present study proposes an integrated approach to the assessment of the potential environmental impact of three foaming agents containing different anionic surfactants and other polymers currently on the market and used in tunnel boring machines. The strategy includes chemical characterization with high resolution mass spectrometry techniques to identify the components of each product, the use of in silico tools to perform a similarity comparison among these compounds and some pollutants already listed in regulatory frameworks to identify possible threshold concentrations of contamination, and the application of a battery of ecotoxicological assays to investigate the impact of each foaming mixture on model organisms of soil (higher plants and Eisenia andrei) and water communities (Daphnia magna). The study identified eleven compounds not listed on the material safety data sheets for which we have identified possible concentrations of contamination based on existing regulatory references. The bioassays allowed us to determine the no effect concentrations (NOAECs) of the three mixtures, which were subsequently used as threshold concentration for the product in its entirety. The technical mixtures used in this study have a different degree of toxicity and the predicted environmental concentrations based on the conditions of use are lower than the NOAEC for soils but higher than the NOAEC for water, posing a potential risk to the waters due to the levels of foaming agents in the muck. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultrasonic enhancement of battery diffusion.

PubMed

Hilton, R; Dornbusch, D; Branson, K; Tekeei, A; Suppes, G J

2014-03-01

It has been demonstrated that sonic energy can be harnessed to enhance convection in Galvanic cells during cyclic voltammetry; however, the practical value of this approach is limited due to the lack of open volumes for convection patterns to develop in most batteries. This study evaluates the ability of ultrasonic waves to enhance diffusion in membrane separators commonly used in sandwich-architecture batteries. Studies include the measuring of open-circuit performance curves to interpret performances in terms of reductions in concentration overpotentials. The use of a 40 kHz sonicator bath can consistently increase the voltage of the battery and reduce overpotential losses up to 30%. This work demonstrates and quantifies battery enhancement due to enhanced diffusion made possible with ultrasonic energy. Copyright © 2013 Elsevier B.V. All rights reserved.

Theory of the interplay between the superconductivity and the blocked antiferromagnetic order in A(y)Fe(2-x)Se2.

PubMed

Jiang, Hong-Min

2012-09-26

Based on an effective two-orbital tight-binding model, we examine the possible superconducting states in iron-vacancy-ordered A(y)Fe(2-x)Se(2). In the presence of ordered vacancies and blocked antiferromagnetic order, it is shown that the emergent SC pairing is the nodeless next-nearest-neighbor (NNN)-pairing due to the dominant antiferromagnetic (AFM) interaction between the inter-block NNN sites. In particular, we show that due to the ordered vacancies and the associated blocked AFM order, the interplay between the superconducting and AFM states results in three distinct states in the phase diagram as doping is varied. The divergent experimental observations can be accounted for by considering the different charge carrier concentrations in their respective compounds.

Analysis of Inorganic Nanoparticles by Single-particle Inductively Coupled Plasma Time-of-Flight Mass Spectrometry.

PubMed

Hendriks, Lyndsey; Gundlach-Graham, Alexander; Günther, Detlef

2018-04-25

Due to the rapid development of nanotechnologies, engineered nanomaterials (ENMs) and nanoparticles (ENPs) are becoming a part of everyday life: nanotechnologies are quickly migrating from laboratory benches to store shelves and industrial processes. As the use of ENPs continues to expand, their release into the environment is unavoidable; however, understanding the mechanisms and degree of ENP release is only possible through direct detection of these nanospecies in relevant matrices and at realistic concentrations. Key analytical requirements for quantitative detection of ENPs include high sensitivity to detect small particles at low total mass concentrations and the need to separate signals of ENPs from a background of dissolved elemental species and natural nanoparticles (NNPs). To this end, an emerging method called single-particle inductively coupled plasma mass spectrometry (sp-ICPMS) has demonstrated great potential for the characterization of inorganic nanoparticles (NPs) at environmentally relevant concentrations. Here, we comment on the capabilities of modern sp-ICPMS analysis with particular focus on the measurement possibilities offered by ICP-time-of-flight mass spectrometry (ICP-TOFMS). ICP-TOFMS delivers complete elemental mass spectra for individual NPs, which allows for high-throughput, untargeted quantitative analysis of dispersed NPs in natural matrices. Moreover, the multi-element detection capabilities of ICP-TOFMS enable new NP-analysis strategies, including online calibration via microdroplets for accurate NP mass quantification and matrix compensation.

Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples

PubMed Central

Lombi, Enzo; de Jonge, Martin D.; Donner, Erica; Kopittke, Peter M.; Howard, Daryl L.; Kirkham, Robin; Ryan, Chris G.; Paterson, David

2011-01-01

Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples. PMID:21674049

Solubilization of single-walled carbon nanotubes using a peptide aptamer in water below the critical micelle concentration.

PubMed

Li, Zha; Kameda, Tomoshi; Isoshima, Takashi; Kobatake, Eiry; Tanaka, Takeshi; Ito, Yoshihiro; Kawamoto, Masuki

2015-03-24

The solubilizing ability of single-walled carbon nanotubes (SWCNTs) in water with several dispersants was investigated. Among the dispersants, including low-molecular-weight surfactants, peptides, DNA, and a water-soluble polymer, the peptide aptamer, A2 (IFRLSWGTYFS), exhibited the highest dispersion capability below the critical micelle concentration at a concentration of 0.02 w/v%. The dispersion of supernatant aqueous solution of SWCNTs containing aptamer A2 was essentially unchanged for several months after high-speed ultracentrifugation and gave rise to an efficient and stable dispersion of the SWCNTs in water. From the results of isothermal titration calorimetry and molecular dynamics simulations, the effective binding capability of A2 was due to π-π interaction between aromatic groups in the peptide aptamer and the side walls of SWCNTs. Interestingly, the peptide aptamer showed the possibility of diameter separation of semiconducting SWCNTs using a uniform density gradient ultracentrifuge. These phenomena are encouraging results toward an effective approach to the dispersion and separation of SWCNTs.

Pollution Assessment of Toxic and Potentially Toxic Elements in Agricultural Soils of the City Addis Ababa, Ethiopia.

PubMed

Aschale, Minbale; Sileshi, Yilma; Kelly-Quinn, Mary; Hailu, Dereje

2017-02-01

Due to the significantly fast urban expansion and increased industrial activities, the soils in the farms in Addis Ababa are contaminated by some toxic and potentially toxic elements (As, V, Cr, Fe, Co, Ni, Cu, B, Ba, Sr, Zn, Mn, Pb and Cd) in varying degrees. The mean concentrations of Cr, Ni, As and B in most of the soil farms were found to be higher than the maximum recommended limits. The mean concentrations of Cd, Cu, Pb, Co, Ni and Mn were found to be higher than the background soil concentrations given for uncontaminated soils. Multivariate analyses coupled with correlation analysis were used to identify possible sources. The geo-accumulation index values for Cr, Mn and Pb indicated that the farm soils were unpolluted to moderately polluted as a result of anthropogenic activities. A comprehensive environmental management strategy should be formulated by the government to measure further pollution of the farmland soil.

Biogeochemical effects of forest vegetation on acid precipitation-related water chemistry: a case study in southwest China.

PubMed

Chen, Jing; Li, Wei; Gao, Fang

2010-10-06

The elemental composition of rainwater, throughfall, and soil solutions of a forest ecosystem in the acid rain control region of southwest China was investigated during 2007-2008 to assess the acid buffering capacity of different forest covers. A possible seasonal distribution of wet deposition was identified. Sulfur was determined as the dominant acidification precursor in this region. The chemical composition of rainfall intercepted by the forest canopy was modified substantially; generally the ion concentrations were increased by dry deposition and foliar leaching. As an exception, the concentration of NH(4)(+) and NO(3)(-) decreased in throughfall, which was probably due to the absorption of nitrogen by the leaves. Elemental concentrations in soil solutions decreased with depth. The water conservation capacity of different forests was also evaluated. The most appropriate forest vegetation for water conservation and remediation of acid precipitation in this region was explored for the sake of ecosystem management, ecological restoration and economic development.

Network formation of nanofibrillated cellulose in solution blended poly(methyl methacrylate) composites.

PubMed

Littunen, Kuisma; Hippi, Ulla; Saarinen, Tapio; Seppälä, Jukka

2013-01-02

Composites of poly(methyl methacrylate) (PMMA) and nanofibrillated cellulose (NFC) were prepared by solution blending and further processed by injection and compression molding. To improve adhesion at the PMMA/NFC interface, the nanofibrils were covalently grafted with PMMA. Formation of a percolating nanofibril network was observed between 1 and 5 wt.% of NFC by dynamic rotational rheometry in molten state. This observation was further supported by the behavior of glass transition temperature which decreased at low NFC concentrations but recovered above the percolation threshold, indicating a decreased mobility of the matrix polymer. This effect was more pronounced with ungrafted NFC, possibly due to a stronger network. The unmodified NFC induced a minor degradation of the molar mass of PMMA. As thin plates, the composites were transparent at low NFC concentrations but became partially aggregated at the highest NFC concentrations. Despite the continuous NFC network, tensile testing showed no improvement of the mechanical properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

Geographical and pedological drivers of distribution and risks to soil fauna of seven metals (Cd, Cu, Cr, Ni, Pb, V and Zn) in British soils.

PubMed

Spurgeon, David J; Rowland, Philip; Ainsworth, Gillian; Rothery, Peter; Long, Sara; Black, Helaina I J

2008-05-01

Concentrations of seven metals were measured in over 1000 samples as part of an integrated survey. Sixteen metal pairs were significantly positively correlated. Cluster analysis identified two clusters. Metals from the largest (Cr, Cu, Ni, V, Zn), but not the smallest (Cd, Pb) cluster were significantly negatively correlated with spatial location and soil pH and organic matter content. Cd and Pb were not correlated with these parameters, due possibly to the masking effect of recent extensive release. Analysis of trends with soil properties in different habitats indicated that general trends may not necessarily be applicable to all areas. A risk assessment indicated that Zn poses the most widespread direct risk to soil fauna and Cd the least. Any risks associated with high metal concentrations are, however, likely to be greatest in habitats such as arable and horticultural, improved grassland and built up areas where soil metal concentrations are more frequently elevated.

Urea removal coupled with enhanced electricity generation in single-chambered microbial fuel cells.

PubMed

Wang, Luguang; Xie, Beizhen; Gao, Ningshengjie; Min, Booki; Liu, Hong

2017-09-01

High concentration of total ammonia nitrogen (TAN) in the form of urea is known to inhibit the performance of many biological wastewater treatment processes. Microbial fuel cells (MFCs) have great potential for TAN removal due to its unique oxic/anoxic environment. In this study, we demonstrated that increased urea (TAN) concentration up to 3940 mg/L did not inhibit power output of single-chambered MFCs, but enhanced power generation by 67% and improved coulombic efficiency by 78% compared to those obtained at 80 mg/L of TAN. Over 80% of nitrogen removal was achieved at TAN concentration of 2630 mg/L. The increased nitrogen removal coupled with significantly enhanced coulombic efficiency, which was observed for the first time, indicates the possibility of a new electricity generation mechanism in MFCs: direct oxidation of ammonia for power generation. This study also demonstrates the great potential of using one MFC reactor to achieve simultaneous electricity generation and urea removal from wastewater.

Integration of concentrated solar power (CSP) and circulating fluidized bed (CFB) power plants - final results of the COMBO-CFB project

NASA Astrophysics Data System (ADS)

Suojanen, Suvi; Hakkarainen, Elina; Kettunen, Ari; Kapela, Jukka; Paldanius, Juha; Tuononen, Minttu; Selek, Istvan; Kovács, Jenö; Tähtinen, Matti

2017-06-01

Hybridization of solar energy together with another energy source is an option to provide heat and power reliably on demand. Hybridization allows decreasing combustion related fuel consumption and emissions, assuring stable grid connection and cutting costs of concentrated solar power technology due to shared power production equipment. The research project "Integration of Concentrated Solar Power (CSP) and Circulating Fluidized Bed (CFB) Power Plants" (COMBO-CFB) has been carried out to investigate the technical possibilities and limitations of the concept. The main focus was on the effect of CSP integration on combustion dynamics and on the joint power cycle, and on the interactions of subsystems. The research provides new valuable experimental data and knowhow about dynamic behaviour of CFB combustion under boundary conditions of the hybrid system. Limiting factors for maximum solar share in different hybridization schemes and suggestions for enhancing the performance of the hybrid system are derived.

Background biomonitoring of residue levels of 137 pesticides in the blood plasma of the general population in Beijing.

PubMed

Li, Jiaxin; Wang, Pengsi; Shi, Shangmei; Xue, Jian

2018-04-29

Due to the widespread use of pesticides, human exposure to pesticides is possible and can potentially cause adverse impacts on public health. We measured 137 pesticides including organophosphorus, organochlorine, pyrethroid and carbamate pesticides together with various herbicides in 100 human blood samples collected from the general population in Beijing. The samples were analysed by triple quadrupole tandem gas chromatography-mass spectrometry. In total, 24 organochlorine pesticides, 5 pyrethroid pesticides and 6 organophosphorus pesticides were detected. The detection rates of HCB, α-HCH, β-HCH, γ-HCH, p,p'-DDE and quintozene were 99, 96, 74, 72, 96 and 95%, respectively. No statistically significant gender difference in the blood concentrations of the pesticides was found. Consistent with the trend of the increasing β-HCH, p,p'-DDE and quintozene concentrations with age, a strong positive correlation between the age and concentrations of β-BHC, p,p'-DDE and quintozene was observed.

Trace Elements in the Marine Sediments of the La Paz Lagoon, Baja California Peninsula, Mexico: Pollution Status in 2013.

PubMed

Pérez-Tribouillier, Habacuc; Shumilin, Evgueni; Rodríguez-Figueroa, Griselda Margarita

2015-07-01

To determine the actual concentrations of trace elements in surface sediments from the La Paz Lagoon, as well as their associations and possible origins, 91 sediment samples were analyzed for more than 50 elements using a combination of ICP-MS and ICP-AES. The results of a principal component analysis are used to distinguish four associative groups within the elements. Natural enrichment of As, Cd and U occurs due to the supply of weathered phosphorites from the El Cien formation located to the north-west of the lagoon. Sediment quality indices for potentially toxic trace elements do not show any probable impact on the biota of the lagoon. Only the concentrations of As in 30 % of the stations and Cu in 20 % of them exceed related effect range low levels. The highest concentration of Pb (36.8 mg kg(-1)) was measured in the sediments near the City of La Paz.

Electron transport characteristics of silicon nanowires by metal-assisted chemical etching

NASA Astrophysics Data System (ADS)

Qi, Yangyang; Wang, Zhen; Zhang, Mingliang; Wang, Xiaodong; Ji, An; Yang, Fuhua

2014-03-01

The electron transport characteristics of silicon nanowires (SiNWs) fabricated by metal-assisted chemical etching with different doping concentrations were studied. By increasing the doping concentration of the starting Si wafer, the resulting SiNWs were prone to have a rough surface, which had important effects on the contact and the electron transport. A metal-semiconductor-metal model and a thermionic field emission theory were used to analyse the current-voltage (I-V) characteristics. Asymmetric, rectifying and symmetric I-V curves were obtained. The diversity of the I-V curves originated from the different barrier heights at the two sides of the SiNWs. For heavily doped SiNWs, the critical voltage was one order of magnitude larger than that of the lightly doped, and the resistance obtained by differentiating the I-V curves at large bias was also higher. These were attributed to the lower electron tunnelling possibility and higher contact barrier, due to the rough surface and the reduced doping concentration during the etching process.

Effects of γ-ray irradiation on optical absorption and laser damage performance of KDP crystals containing arsenic impurities.

PubMed

Guo, D C; Jiang, X D; Huang, J; Wang, F R; Liu, H J; Xiang, X; Yang, G X; Zheng, W G; Zu, X T

2014-11-17

The effects of γ-irradiation on potassium dihydrogen phosphate crystals containing arsenic impurities are investigated with different optical diagnostics, including UV-VIS absorption spectroscopy, photo-thermal common-path interferometer and photoluminescence spectroscopy. The optical absorption spectra indicate that a new broad absorption band near 260 nm appears after γ-irradiation. It is found that the intensity of absorption band increases with the increasing irradiation dose and arsenic impurity concentration. The simulation of radiation defects show that this absorption is assigned to the formation of AsO₄⁴⁻ centers due to arsenic ions substituting for phosphorus ions. Laser-induced damage threshold test is conducted by using 355 nm nanosecond laser pulses. The correlations between arsenic impurity concentration and laser induced damage threshold are presented. The results indicate that the damage performance of the material decreases with the increasing arsenic impurity concentration. Possible mechanisms of the irradiation-induced defects formation under γ-irradiation of KDP crystals are discussed.

Long-term changes in fish mercury levels in the historically impacted English-Wabigoon River system (Canada).

PubMed

Neff, Margaret R; Bhavsar, Satyendra P; Arhonditsis, George B; Fletcher, Rachael; Jackson, Donald A

2012-09-01

The English-Wabigoon River system in Northwestern Ontario, Canada, was one of the most heavily mercury-contaminated waterways in the world due to historical discharges in the 1960s from a chlor-alkali plant. This study examines long-term (1970-2010) monitoring data to assess temporal trends in mercury contamination in Walleye, Northern Pike and Lake Whitefish, three species important for sport and subsistence fishing in this region, using dynamic linear modeling and piecewise regression. For all lakes and species, there is a significant decline (36-94%) in mercury concentrations through time; however, there is evidence that this decline is either slowing down or levelling off. Concentrations in the English-Wabigoon fish are elevated, and may still present a potential health risk to humans consuming fish from this system. Various biotic and abiotic factors are examined as possible explanations to slowing rates of decline in mercury concentrations observed in the mid-1980s.

Comparison of para-aminophenol cytotoxicity in rat renal epithelial cells and hepatocytes.

PubMed

Li, Ying; Bentzley, Catherine M; Tarloff, Joan B

2005-04-01

Several chemicals, including para-aminophenol (PAP), produce kidney damage in the absence of hepatic damage. Selective nephrotoxicity may be related to the ability of the kidney to reabsorb filtered water, thereby raising the intraluminal concentration of toxicants and exposing tubular epithelial cells to higher concentrations than would be present in other tissues. The present experiments tested the hypothesis that hepatocytes and renal epithelial cells exposed to equivalent concentrations of PAP would be equally susceptible to toxicity. Hepatocytes and renal epithelial cells were prepared by collagenase digestion of tissues obtained from female Sprague-Dawley rats. Toxicity was monitored using trypan blue exclusion, oxygen consumption and ATP content. We measured the rate of PAP clearance and formation of PAP-glutathione conjugate by HPLC. We found that renal epithelial cells accumulated trypan blue and showed declines in oxygen consumption and ATP content at significantly lower concentrations of PAP and at earlier time points than hepatocytes. The half-life of PAP in hepatocyte incubations was significantly shorter (0.71+/-0.07 h) than in renal epithelial cell incubations (1.33+/-0.23 h), suggesting that renal epithelial cells were exposed to PAP for longer time periods than hepatocytes. Renal epithelial cells formed significantly less glutathione conjugates of PAP (PAP-SG) than did hepatocytes, consistent with less efficient detoxification of reactive PAP intermediates by renal epithelial cells. Finally, hepatocytes contained significant more reduced glutathione (NPSH) than did renal epithelial cells, possibly explaining the enhanced formation of PAP-SG by this cell population. In conclusion, our data indicates that renal epithelial cells are intrinsically more susceptible to PAP cytotoxicity than are hepatocytes. This enhanced cytotoxicity may be due to longer exposure to PAP and/or reduced detoxification of reactive intermediates due to lower concentrations of reduced NPSH in renal epithelial cells than in hepatocytes.

Effect of different concentrations of oxygen on expression of sigma 1 receptor and superoxide dismutases in human colon adenocarcinoma cell lines.

PubMed

Skrzycki, Michał; Czeczot, Hanna; Mielczarek-Puta, Magdalena; Otto-Ślusarczyk, Dagmara; Graboń, Wojciech

2017-06-01

Tumor cells due to distance from capillary vessels exist in different oxygenation conditions (anoxia, hypoxia, normoxia). Changes in cell oxygenation lead to reactive oxygen species production and oxidative stress. Sigma 1 receptor (Sig1R) is postulated to be stress responding agent and superoxide dismutases (SOD1 and SOD2) are key antioxidant enzymes. It is possible that they participate in tumor cells adaptation to different concentrations of oxygen. Evaluation of Sig1R, SOD1, and SOD2 expression in different concentrations of oxygen (1%, 10%, 21%) in colon adenocarcinoma cell lines. SW480 (primary adenocarcinoma) and SW620 (metastatic) cell lines were cultured in standard conditions in Dulbecco's modified Eagle's medium for 5 days, and next cultured in Hypoxic Chamber in 1% O 2 , 10% O 2 , 21% O 2 . Number of living cells was determined by trypan blue assay. Level of mRNA for Sig1R, SOD1, and SOD2 was determined by standard PCR method. Statistical analysis was conducted using Statistica 10.1 software. We observed significant changes in expression of Sig1R, SOD1, SOD2 due to different oxygen concentrations. ANOVA analysis revealed significant interactions between studied parameters mainly in hypoxia conditions in SW480 cells and between Sig1R and SOD2 in SW620 cells. It also showed that changes in expression of studied proteins depend significantly on type of the cell line. Changes of Sig1R and SOD2 expression point to mitochondria as main organelle responsible for survival of tumor cells exposed to hypoxia or oxidative stress. Studied proteins are involved in intracellular response to stress related with different concentrations of oxygen.

Management practices impact vine carbohydrate status to a greater extent than vine productivity

PubMed Central

Pellegrino, Anne; Clingeleffer, Peter; Cooley, Nicola; Walker, Rob

2014-01-01

Light pruning and deficit irrigation regimes are practices which are widely used in high yielding commercial vineyards in the warm climate regions of Australia. Little information is available on their impacts on carbohydrate dynamics in vegetative organs within and between seasons, and on the resulting plant capacity to maintain productivity and ripen fruits. This study was conducted to address this gap in knowledge over five vintages on Vitis vinifera L. cv. Cabernet Franc, Shiraz, and Cabernet Sauvignon in the Sunraysia region of Victoria, Australia. Lighter pruning did not change the total carbohydrates concentration and composition in wood and roots within seasons in Cabernet Franc and Shiraz. However, the total carbohydrate pool (starch and soluble sugars) at the end of dormancy increased under lighter pruning, due to higher vine size, associated with retention and growth of old-wood (trunk and cordons). Water deficit negatively impacted trunk and leaf starch concentrations, over the day and within seasons in Cabernet Sauvignon. Soluble sugars concentrations in these tissues tended to be higher under limited water supply, possibly due to higher sugar mobilization as photosynthesis decreased. Trunk carbohydrate concentrations markedly varied within and between seasons, highlighting the importance of interactive factors such as crop load and climate on carbon status. The period between fruit-set and véraison was shown to be critical for its impact on the balance between carbon accretion and depletion, especially under water deficit. The lower leaf and trunk starch concentration under water deficit resulted in a decrease of yield components at harvest, while similar yields were reached for all pruning systems. The sugar allocated to berries at harvest remained remarkably stable for all practices and seasons, irrespective of vine yield and carbohydrate status in vegetative organs in Shiraz and Cabernet Sauvignon. PMID:25018758

Effects of fluorine on crops, soil exoenzyme activities, and earthworms in terrestrial ecosystems.

PubMed

Chae, Yooeun; Kim, Dokyung; An, Youn-Joo

2018-04-30

Fluorine can flow into the environment after leakage or spill accidents and these excessive amounts can cause adverse effects on terrestrial ecosystems. Using three media (filter paper, soil, and filter-paper-on-soil), we investigated the toxic effects of fluorine on the germination and growth of crops (barley, mung bean, sorghum, and wheat), on the activities of soil exoenzymes (acid phosphatase, arylsulfatase, fluorescein diacetate hydrolase, and urease) and on the survival, abnormality, and cytotoxicity of Eisenia andrei earthworms. The germination and growth of crops were affected by fluorine as exposure concentration increased. The activities of the four enzymes after 0-, 3-, 10-, and 20-day periods varied as exposure concentration increased. According to in vivo and in vitro earthworm assays, E. andrei mortality, abnormality, and cytotoxicity increased with increasing fluorine concentration. Overall, fluorine significantly affected each tested species in the concentration ranges used in this study. The activities of soil exoenzymes were also affected by soil fluorine concentration, although in an inconsistent manner. Albeit the abnormally high concentrations of fluorine in soil compared to that observed under natural conditions, its toxicity was much restrained possibly due to the adsorption of fluorine on soil particles and its combination with soil cations. Copyright © 2017 Elsevier Inc. All rights reserved.

Arsenic: Association of regional concentrations in drinking water with suicide and natural causes of death in Italy.

PubMed

Pompili, Maurizio; Vichi, Monica; Dinelli, Enrico; Erbuto, Denise; Pycha, Roger; Serafini, Gianluca; Giordano, Gloria; Valera, Paolo; Albanese, Stefano; Lima, Annamaria; De Vivo, Benedetto; Cicchella, Domenico; Rihmer, Zoltan; Fiorillo, Andrea; Amore, Mario; Girardi, Paolo; Baldessarini, Ross J

2017-03-01

Arsenic, as a toxin, may be associated with higher mortality rates, although its relationship to suicide is not clear. Given this uncertainty, we evaluated associations between local arsenic concentrations in tapwater and mortality in regions of Italy, to test the hypothesis that both natural-cause and suicide death rates would be higher with greater trace concentrations of arsenic. Arsenic concentrations in drinking-water samples from 145 sites were assayed by mass spectrometry, and correlated with local rates of mortality due to suicide and natural causes between 1980 and 2011, using weighted, least-squares univariate and multivariate regression modeling. Arsenic concentrations averaged 0.969 (CI: 0.543-1.396) µg/L, well below an accepted safe maximum of 10µg/L. Arsenic levels were negatively associated with corresponding suicide rates, consistently among both men and women in all three study-decades, whereas mortality from natural causes increased with arsenic levels. Contrary to an hypothesized greater risk of suicide with higher concentrations of arsenic, we found a negative association, suggesting a possible protective effect, whereas mortality from natural causes was increased, in accord with known toxic effects of arsenic. The unexpected inverse association between arsenic and suicide requires further study. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Increased N2O emission by inhibited plant growth in the CO2 leaked soil environment: Simulation of CO2 leakage from carbon capture and storage (CCS) site.

PubMed

Kim, You Jin; He, Wenmei; Ko, Daegeun; Chung, Haegeun; Yoo, Gayoung

2017-12-31

Atmospheric carbon dioxide (CO 2 ) concentrations is continuing to increase due to anthropogenic activity, and geological CO 2 storage via carbon capture and storage (CCS) technology can be an effective way to mitigate global warming due to CO 2 emission. However, the possibility of CO 2 leakage from reservoirs and pipelines exists, and such leakage could negatively affect organisms in the soil environment. Therefore, to determine the impacts of geological CO 2 leakage on plant and soil processes, we conducted a greenhouse study in which plants and soils were exposed to high levels of soil CO 2 . Cabbage, which has been reported to be vulnerable to high soil CO 2 , was grown under BI (no injection), NI (99.99% N 2 injection), and CI (99.99% CO 2 injection). Mean soil CO 2 concentration for CI was 66.8-76.9% and the mean O 2 concentrations in NI and CI were 6.6-12.7%, which could be observed in the CO 2 leaked soil from the pipelines connected to the CCS sites. The soil N 2 O emission was increased by 286% in the CI, where NO 3 - -N concentration was 160% higher compared to that in the control. This indicates that higher N 2 O emission from CO 2 leakage could be due to enhanced nitrification process. Higher NO 3 - -N content in soil was related to inhibited plant metabolism. In the CI treatment, chlorophyll content decreased and chlorosis appeared after 8th day of injection. Due to the inhibited root growth, leaf water and nitrogen contents were consistently lowered by 15% under CI treatment. Our results imply that N 2 O emission could be increased by the secondary effects of CO 2 leakage on plant metabolism. Hence, monitoring the environmental changes in rhizosphere would be very useful for impact assessment of CCS technology. Copyright © 2017 Elsevier B.V. All rights reserved.

Uptake, tissue distribution and depuration of triclosan in the guppy Poecilia vivipara acclimated to freshwater.

PubMed

Escarrone, Ana Laura Venquiaruti; Caldas, Sergiane Souza; Primel, Ednei Gilberto; Martins, Samantha Eslava; Nery, Luiz Eduardo Maia

2016-08-01

The agent triclosan has been extensively used in different personal care products as a broad-spectrum antimicrobial and preservative agent. Due to its continuous release into the environment, including discharge via wastewater treatment plants, triclosan has been widely detected in aquatic environments. There is growing interest in improving the knowledge about the environmental fate of triclosan due to its possible bioaccumulation and the toxicity it may pose to organisms, such as fish and other non-target species. To investigate the distribution and bioconcentration of triclosan in fish, Poecilia vivipara was exposed to 0.2mgL(-1). Contents of triclosan in whole fish, brain, gonads, liver, muscle and gills were quantified by LC-MS/MS. When lipid normalised concentration was used, the liver exhibited the highest concentration followed by the gills, gonads, brain and muscle tissues. Bioconcentration was increased with time reaching a steady-state around 7-14days for most all tissues. After 24h depuration, triclosan concentrations declined >80% in all tissues except liver, in which triclosan takes longer to be depurated. These results not only clearly indicate that triclosan accumulated in P. vivipara, with tissue-specific bioconcentration factors (BCF) that ranged from 40.2 to 1025.4, but also show that the elimination of triclosan after transferring the fish to triclosan-free freshwater is rapid in all tissues. Copyright © 2016 Elsevier B.V. All rights reserved.

Pharmacokinetic and pharmacodynamic drug interactions of carbamazepine and glibenclamide in healthy albino Wistar rats

PubMed Central

Prashanth, S.; Kumar, A. Anil; Madhu, B.; Rama, N.; Sagar, J. Vidya

2011-01-01

Aims: To find out the pharmacokinetic and pharmacodynamic drug interaction of carbamazepine, a protype drug used to treat painful diabetic neuropathy with glibenclamide in healthy albino Wistar rats following single and multiple dosage treatment. Materials and Methods: Therapeutic doses (TD) of glibenclamide and TD of carbamazepine were administered to the animals. The blood glucose levels were estimated by GOD/POD method and the plasma glibenclamide concentrations were estimated by a sensitive RP HPLC method to calculate pharmacokinetic parameters. Results: In single dose study the percentage reduction of blood glucose levels and glibenclamide concentrations of rats treated with both carbamazepine and glibenclamide were significantly increased when compared with glibenclamide alone treated rats and the mechanism behind this interaction may be due to inhibition of P-glycoprotein mediated transport of glibenclamide by carbamazepine, but in multiple dose study the percentage reduction of blood glucose levels and glibenclamide concentrations were reduced and it may be due to inhibition of P-glycoprotein mediated transport and induction of CYP2C9, the enzyme through which glibenclamide is metabolised. Conclusions: In the present study there is a pharmacokinetic and pharmacodynamic interaction between carbamazepine and glibenclamide was observed. The possible interaction involves both P-gp and CYP enzymes. To investigate this type of interactions pre-clinically are helpful to avoid drug-drug interactions in clinical situation. PMID:21701639

Influence of functionalized nanoparticles on conformational stability of type I collagen for possible biomedical applications.

PubMed

Kandamchira, Aswathy; Selvam, Sangeetha; Marimuthu, Nidhin; Janardhanan, Sreeram Kalarical; Fathima, Nishter Nishad

2013-12-01

Collagen-nanoparticle interactions are vital for many biomedical applications including drug delivery and tissue engineering applications. Iron oxide nanoparticles synthesized using starch template according to our earlier reported procedures were functionalized by treating them with Gum Arabic (GA), a biocompatible polysaccharide, so as to enhance the interaction between nanoparticle surfaces and collagen. Viscosity, circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) techniques have been used to study the collagen-nanoparticle interactions. The relative viscosity for collagen-nanoparticle conjugate was found to increase with increase in concentration of the nanoparticle within the concentration range investigated, which is due to the aggregation of protein onto the surface of nanoparticle. The CD spectra for the collagen-nanoparticle at different concentration ratios do not have much variation in the Rpn values (ratio of positive peak intensity over negative peak intensity) after functionalization with GA. The variation of molar ellipticity values for collagen-nanoparticle is due to the glycoprotein present in GA. The collagen triple helical structure is maintained after interaction with nanoparticles. The FTIR spectra of native collagen, Coll-Fs (nanoparticle without functionalization) and Coll-FsG (nanoparticle functionalized with GA) show clearly the amide I, II, III bands, with respect to collagen. The ability of polysaccharide stabilized/functionalized nanoparticles to maintain the collagen properties would help in its biomedical applications. © 2013.

Export of dissolved carbonaceous and nitrogenous substances in rivers of the "Water Tower of Asia".

PubMed

Qu, Bin; Sillanpää, Mika; Kang, Shichang; Yan, Fangping; Li, Zhiguo; Zhang, Hongbo; Li, Chaoliu

2018-03-01

Rivers are critical links in the carbon and nitrogen cycle in aquatic, terrestrial, and atmospheric environments. Here riverine carbon and nitrogen exports in nine large rivers on the Tibetan Plateau - the "Water Tower of Asia" - were investigated in the monsoon season from 2013 to 2015. Compared with the world average, concentrations of dissolved inorganic carbon (DIC, 30.7mg/L) were high in river basins of the plateau due to extensive topographic relief and intensive water erosion. Low concentrations of dissolved organic carbon (DOC, 1.16mg/L) were likely due to the low temperature and unproductive land vegetation environments. Average concentrations of riverine DIN (0.32mg/L) and DON (0.35 mg/L) on the Tibetan Plateau were close to the world average. However, despite its predominantly pristine environment, discharge from agricultural activities and urban areas of the plateau has raised riverine N export. In addition, DOC/DON ratio (C/N, ~6.5) in rivers of the Tibetan Plateau was much lower than the global average, indicating that dissolved organic carbon in the rivers of this region might be more bioavailable. Therefore, along with global warming and anthropogenic activities, increasing export of bioavailable riverine carbon and nitrogen from rivers of the Tibetan Plateau can be expected in the future, which will possibly influence the regional carbon and nitrogen cycle. Copyright © 2017. Published by Elsevier B.V.

Suppression of activation energy and superconductivity by the addition of Al{sub 2}O{sub 3} nanoparticles in CuTl-1223 matrix

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

Jabbar, Abdul; Qasim, Irfan; Mumtaz, M.

2014-05-28

Low anisotropic (Cu{sub 0.5}Tl{sub 0.5})Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10−δ} (CuTl-1223) high T{sub c} superconducting matrix was synthesized by solid-state reaction and Al{sub 2}O{sub 3} nanoparticles were prepared separately by co-precipitation method. Al{sub 2}O{sub 3} nanoparticles were added with different concentrations during the final sintering cycle of CuTl-1223 superconducting matrix to get the required (Al{sub 2}O{sub 3}){sub y}/CuTl-1223, y = 0.0, 0.5, 0.7, 1.0, and 1.5 wt. %, composites. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray, and dc-resistivity (ρ) measurements. The activation energy and superconductivity were suppressed with increasing concentration of Al{sub 2}O{sub 3} nanoparticles in (CuTl-1223) matrix.more » The XRD analysis showed that the addition of Al{sub 2}O{sub 3} nanoparticles did not affect the crystal structure of the parent CuTl-1223 superconducting phase. The suppression of activation energy and superconducting properties is most probably due to weak flux pinning in the samples. The possible reason of weak flux pinning is reduction of weak links and enhanced inter-grain coupling due to the presence of Al{sub 2}O{sub 3} nanoparticles at the grain boundaries. The presence of Al{sub 2}O{sub 3} nanoparticles at the grain boundaries possibly reduced the number of flux pinning centers, which were present in the form of weak links in the pure CuTl-1223 superconducting matrix. The increase in the values of inter-grain coupling (α) deduced from the fluctuation induced conductivity analysis with the increased concentration of Al{sub 2}O{sub 3} nanoparticles is a theoretical evidence of improved inter-grain coupling.« less

Blood levels of toxic metals and rare earth elements commonly found in e-waste may exert subtle effects on hemoglobin concentration in sub-Saharan immigrants.

PubMed

Henríquez-Hernández, Luis Alberto; Boada, Luis D; Carranza, Cristina; Pérez-Arellano, José Luis; González-Antuña, Ana; Camacho, María; Almeida-González, Maira; Zumbado, Manuel; Luzardo, Octavio P

2017-12-01

Pollution by heavy metals and more recently by rare earth elements (REE) and other minor elements (ME) has increased due in part to their high use in technological and electronic devices. This contamination can become very relevant in those sites where e-waste is improperly processed, as it is the case in many countries of the African continent. Exposure to some toxic elements has been associated to certain hematological disorders, specifically anemia. In this study, the concentrations of 48 elements (including REE and other ME) were determined by ICP-MS in whole blood samples of sub-Saharan immigrants with anemia (n=63) and without anemia (n=78). We found that the levels of Fe, Cr, Cu, Mn, Mo, and Se were significantly higher in the control group than in the anemia group, suggesting that anemia was mainly due to nutritional deficiencies. However, since other authors have suggested that in addition to nutritional deficiency, exposure to some elements may influence hemoglobin levels, we wanted to explore the role of a broad panel of toxic and "emerging" elements in hemoglobin deficiency. We found that the levels of Ag, As, Ba, Bi, Ce, Eu, Er, Ga, La, Nb, Nd, Pb, Pr, Sm, Sn, Ta, Th, Tl, U and V were higher in anemic participants than in controls. For most of these elements an inverse correlation with hemoglobin concentration was found. Some of them also correlated inversely with blood iron levels, pointing to the possibility that a higher rate of intestinal uptake of these could exist in relation to a nutritional deficiency of iron. However, the higher levels of Pb, and the group of REE and other ME in anemic participants were independent of iron levels, pointing to the possibility that these elements could play a role in the development of anemia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physiological insights into novel therapies for nephrogenic diabetes insipidus.

PubMed

Sands, Jeff M; Klein, Janet D

2016-12-01

Fundamental kidney physiology research can provide important insight into how the kidney works and suggest novel therapeutic opportunities to treat human diseases. This is especially true for nephrogenic diabetes insipidus (NDI). Over the past decade, studies elucidating the molecular physiology and signaling pathways regulating water transport have suggested novel therapeutic possibilities. In patients with congenital NDI due to mutations in the type 2 vasopressin receptor (V2R) or acquired NDI due to lithium (or other medications), there are no functional abnormalities in the aquaporin-2 (AQP2) water channel, or in another key inner medullary transport protein, the UT-A1 urea transporter. If it is possible to phosphorylate and/or increase the apical membrane accumulation of these proteins, independent of vasopressin or cAMP, one may be able to treat NDI. Sildenifil (through cGMP), erlotinib, and simvastatin each stimulate AQP2 insertion into the apical plasma membrane. Some recent human data suggest that sildenafil and simvastatin may improve urine concentrating ability. ONO-AE1-329 (ONO) stimulates the EP4 prostanoid receptor (EP4), which stimulates kinases that in turn phosphorylate AQP2 and UT-A1. Clopidogrel is a P2Y12-R antagonist that potentiates the effect of vasopressin and increases AQP2 abundance. Metformin stimulates AMPK to phosphorylate and activate AQP2 and UT-A1, and it increases urine concentrating ability in two rodent models of NDI. Since metformin, sildenafil, and simvastatin are commercially available and have excellent safety records, the potential for rapidly advancing them into clinical trials is high. Copyright © 2016 the American Physiological Society.

Physiological insights into novel therapies for nephrogenic diabetes insipidus

PubMed Central

2016-01-01

Fundamental kidney physiology research can provide important insight into how the kidney works and suggest novel therapeutic opportunities to treat human diseases. This is especially true for nephrogenic diabetes insipidus (NDI). Over the past decade, studies elucidating the molecular physiology and signaling pathways regulating water transport have suggested novel therapeutic possibilities. In patients with congenital NDI due to mutations in the type 2 vasopressin receptor (V2R) or acquired NDI due to lithium (or other medications), there are no functional abnormalities in the aquaporin-2 (AQP2) water channel, or in another key inner medullary transport protein, the UT-A1 urea transporter. If it is possible to phosphorylate and/or increase the apical membrane accumulation of these proteins, independent of vasopressin or cAMP, one may be able to treat NDI. Sildenifil (through cGMP), erlotinib, and simvastatin each stimulate AQP2 insertion into the apical plasma membrane. Some recent human data suggest that sildenafil and simvastatin may improve urine concentrating ability. ONO-AE1-329 (ONO) stimulates the EP4 prostanoid receptor (EP4), which stimulates kinases that in turn phosphorylate AQP2 and UT-A1. Clopidogrel is a P2Y12-R antagonist that potentiates the effect of vasopressin and increases AQP2 abundance. Metformin stimulates AMPK to phosphorylate and activate AQP2 and UT-A1, and it increases urine concentrating ability in two rodent models of NDI. Since metformin, sildenafil, and simvastatin are commercially available and have excellent safety records, the potential for rapidly advancing them into clinical trials is high. PMID:27534996

Uremic Solutes in Chronic Kidney Disease and Their Role in Progression.

PubMed

van den Brand, Jan A J G; Mutsaers, Henricus A M; van Zuilen, Arjan D; Blankestijn, Peter J; van den Broek, Petra H; Russel, Frans G M; Masereeuw, Rosalinde; Wetzels, Jack F M

2016-01-01

To date, over 150 possible uremic solutes have been listed, but their role in the progression of CKD is largely unknown. Here, the association between a selected panel of uremic solutes and progression in CKD patients was investigated. Patients from the MASTERPLAN study, a randomized controlled trial in CKD patients with a creatinine clearance between 20 and 70 ml/min per 1.73m2, were selected based on their rate of eGFR decline during the first five years of follow-up. They were categorized as rapid (decline >5 ml/min per year) or slow progressors. Concentrations of eleven uremic solutes were obtained at baseline and after one year of follow-up. Logistic regression was used to compare the odds for rapid to slow progression by uremic solute concentrations at baseline. Variability in uremic solute levels was assessed using scatter plots, and limits of variability were calculated. In total, 40 rapidly and 40 slowly progressing patients were included. Uremic solutes were elevated in all patients compared to reference values for healthy persons. The serum levels of uremic solutes were not associated with rapid progression. Moreover, we observed substantial variability in solute levels over time. Elevated concentrations of uremic solutes measured in this study did not explain differences in rate of eGFR decline in CKD patients, possibly due to lack of power as a result of the small sample size, substantial between patient variability, and variability in solute concentrations over time. The etiology of intra-individual variation in uremic solute levels remains to be elucidated.

Radiocarbon and stable-isotope geochemistry of organic and inorganic carbon in Lake Superior

NASA Astrophysics Data System (ADS)

Zigah, Prosper K.; Minor, Elizabeth C.; Werne, Josef P.

2012-03-01

We present a lake-wide investigation of Lake Superior carbon and organic matter biogeochemistry using radiocarbon, stable isotope, and carbon concentrations. Dissolved inorganic carbon (DIC) abundance in the lake was 121-122 Tg C, with offshore concentration andδ13C values being laterally homogenous and tightly coupled to the physical and thermal regime and biochemical processes. Offshore Δ14C of DIC (50-65‰) exhibited lateral homogeneity and was more 14C enriched than co-occurring atmospheric CO2 (˜38‰); nearshore Δ14C of DIC (36-38‰) was similar to atmospheric CO2. Dissolved organic carbon (DOC) abundance was 14.2-16.4 Tg C. DOC's concentration and δ13C were homogenous in June (mixed lake), but varied laterally during August (stratification) possibly due to spatial differences in lake productivity. Throughout sampling, DOC had modern radiocarbon values (14-58‰) indicating a semilabile nature with a turnover time of ≤60 years. Lake particulate organic carbon (POC, 0.9-1.3 Tg C) was consistently 13C depleted relative to DOC. The δ15N of epilimnetic particulate organic nitrogen shifted to more negative values during stratification possibly indicating greater use of nitrate (rather than ammonium) by phytoplankton in August. POC's radiocarbon was spatially heterogeneous (Δ14C range: 58‰ to -303‰), and generally 14C depleted relative to DOC and DIC. POC 14C depletion could not be accounted for by black carbon in the lake but, because of its spatial and temporal distribution, is attributed to sediment resuspension. The presence of old POC within the epilimnion of the open lake indicates possible benthic-pelagic coupling in the lake's organic carbon cycle; the ultimate fate of this old POC bears further investigation.

Development of a real-time radon monitoring system for simultaneous measurements in multiple sites

NASA Astrophysics Data System (ADS)

Yamamoto, S.; Yamasoto, K.; Iida, T.

1999-12-01

A real-time radon monitoring system that can simultaneously measure radon concentrations in multiple sites was developed and tested. The system consists of maximum of four radon detectors, optical fiber cables and a data acquisition personal computer. The radon detector uses a plastic scintillation counter that collects radon daughters in the chamber electrostatically. The applied voltage on the photocathode for the photomultiplier tube (PMT) acts as an electrode for radon daughters. The thickness of the plastic scintillator was thin, 50 /spl mu/m, so as to minimize the background counts due to the environmental gamma rays or beta particles. The energy discriminated signals from the radon detectors are fed to the data acquisition personal computer via optical fiber cables. The system made it possible to measure the radon concentrations in multiple sites simultaneously.

Mercury in fish products: what's the best for consumers between bluefin tuna and yellowfin tuna?

PubMed

Cammilleri, Gaetano; Vazzana, Mirella; Arizza, Vincenzo; Giunta, Francesca; Vella, Antonio; Lo Dico, Gianluigi; Giaccone, Vita; Giofrè, Salvatore V; Giangrosso, Giuseppe; Cicero, Nicola; Ferrantelli, Vincenzo

2018-02-01

A total of 205 bluefin and yellowfin tuna samples were examined for mercury detection in order to verify possible differences and have a detailed risk assessment of the two tuna species. The results showed significant higher mercury concentration in muscle tissue of bluefin tuna respect yellowfin tuna (p < 0.001) with mean concentration of 0.84 mg/kg and maximum value of 1.94 mg/kg. These differences can be due the different biological and ecological aspects of the two tuna species and to different oceanographic aspects between Atlantic Ocean and Mediterranean sea. The results obtained in this study suggest an advisable containment of the sources of pollution and further studies on the closed-loop farming of bluefin tuna, in order to ensure the product safety.

Optimized Production of Xylitol from Xylose Using a Hyper-Acidophilic Candida tropicalis.

PubMed

Tamburini, Elena; Costa, Stefania; Marchetti, Maria Gabriella; Pedrini, Paola

2015-08-19

The yeast Candida tropicalis DSM 7524 produces xylitol, a natural, low-calorie sweetener, by fermentation of xylose. In order to increase xylitol production rate during the submerged fermentation process, some parameters-substrate (xylose) concentration, pH, aeration rate, temperature and fermentation strategy-have been optimized. The maximum xylitol yield reached at 60-80 g/L initial xylose concentration, pH 5.5 at 37 °C was 83.66% (w/w) on consumed xylose in microaerophilic conditions (kLa = 2·h(-1)). Scaling up on 3 L fermenter, with a fed-batch strategy, the best xylitol yield was 86.84% (w/w), against a 90% of theoretical yield. The hyper-acidophilic behaviour of C. tropicalis makes this strain particularly promising for industrial application, due to the possibility to work in non-sterile conditions.

Optimized Production of Xylitol from Xylose Using a Hyper-Acidophilic Candida tropicalis

PubMed Central

Tamburini, Elena; Costa, Stefania; Marchetti, Maria Gabriella; Pedrini, Paola

2015-01-01

The yeast Candida tropicalis DSM 7524 produces xylitol, a natural, low-calorie sweetener, by fermentation of xylose. In order to increase xylitol production rate during the submerged fermentation process, some parameters-substrate (xylose) concentration, pH, aeration rate, temperature and fermentation strategy-have been optimized. The maximum xylitol yield reached at 60–80 g/L initial xylose concentration, pH 5.5 at 37 °C was 83.66% (w/w) on consumed xylose in microaerophilic conditions (kLa = 2·h−1). Scaling up on 3 L fermenter, with a fed-batch strategy, the best xylitol yield was 86.84% (w/w), against a 90% of theoretical yield. The hyper-acidophilic behaviour of C. tropicalis makes this strain particularly promising for industrial application, due to the possibility to work in non-sterile conditions. PMID:26295411

Red phosphorescent organic light-emitting diodes based on the simple structure.

PubMed

Seo, Ji Hyun; Lee, Seok Jae; Kim, Bo Young; Choi, Eun Young; Han, Wone Keun; Lee, Kum Hee; Yoon, Seung Soo; Kim, Young Kwan

2012-05-01

We demonstrated that the simple layered red phosphorescent organic light-emitting diodes (OLEDs) are possible to have high efficiency, low driving voltage, stable roll-off efficiency, and pure emission color without hole injection and transport layers. We fabricated the OLEDs with a structure of ITO/CBP doped with Ir(pq)2(acac)/BPhen/Liq/Al, where the doping concentration of red dopant, Ir(pq)2(acac), was varied from 4% to 20%. As a result, the quantum efficiencies of 13.4, 11.2, 16.7, 10.8 and 9.8% were observed in devices with doping concentrations of 4, 8, 12, 16 and 20%, respectively. Despite of absence of the hole injection and transport layers, these efficiencies are superior to efficiencies of device with hole transporting layer due to direct hole injection from anode to dopant in emission layer.

Emergence of dynamic cooperativity in the stochastic kinetics of fluctuating enzymes

NASA Astrophysics Data System (ADS)

Kumar, Ashutosh; Chatterjee, Sambarta; Nandi, Mintu; Dua, Arti

2016-08-01

Dynamic co-operativity in monomeric enzymes is characterized in terms of a non-Michaelis-Menten kinetic behaviour. The latter is believed to be associated with mechanisms that include multiple reaction pathways due to enzymatic conformational fluctuations. Recent advances in single-molecule fluorescence spectroscopy have provided new fundamental insights on the possible mechanisms underlying reactions catalyzed by fluctuating enzymes. Here, we present a bottom-up approach to understand enzyme turnover kinetics at physiologically relevant mesoscopic concentrations informed by mechanisms extracted from single-molecule stochastic trajectories. The stochastic approach, presented here, shows the emergence of dynamic co-operativity in terms of a slowing down of the Michaelis-Menten (MM) kinetics resulting in negative co-operativity. For fewer enzymes, dynamic co-operativity emerges due to the combined effects of enzymatic conformational fluctuations and molecular discreteness. The increase in the number of enzymes, however, suppresses the effect of enzymatic conformational fluctuations such that dynamic co-operativity emerges solely due to the discrete changes in the number of reacting species. These results confirm that the turnover kinetics of fluctuating enzyme based on the parallel-pathway MM mechanism switches over to the single-pathway MM mechanism with the increase in the number of enzymes. For large enzyme numbers, convergence to the exact MM equation occurs in the limit of very high substrate concentration as the stochastic kinetics approaches the deterministic behaviour.

Inhibition of cough-reflex sensitivity by benzonatate and guaifenesin in acute viral cough.

PubMed

Dicpinigaitis, Peter V; Gayle, Yvonne E; Solomon, Gail; Gilbert, Richard D

2009-06-01

Acute cough due to viral upper respiratory tract infection (URI) is the most common form of cough and accounts for tremendous expenditure on prescription and non-prescription cough products worldwide. However, few agents have been shown in properly conducted clinical trials to be effective for cough due to URI. The present study evaluated the effect of benzonatate 200mg (B), guaifenesin 600 mg (G), their combination (B+G), and placebo (P) on capsaicin-induced cough in 30 adult nonsmokers with acute URI. On 3 separate days within a 7-day period, 1h after ingesting randomly assigned study drug in a double-blind fashion, subjects underwent capsaicin cough challenge testing, which involved inhalation of incremental doubling concentrations of capsaicin until the concentration of capsaicin inducing 5 or more coughs (C(5)) was attained. Each subject received 3 of 4 possible study drugs. G (p=0.01) but not B (p=NS) inhibited cough-reflex sensitivity (log C(5)) relative to P. The combination of B+G suppressed capsaicin-induced cough to a greater degree than B alone (p<0.001) or G alone (p=0.008). The mechanism by which the combination of B+G causes a potentiation of antitussive effect remains to be elucidated. Our results suggest that B+G may be an effective therapy for acute cough due to the common cold (URI).

Emergence of dynamic cooperativity in the stochastic kinetics of fluctuating enzymes.

PubMed

Kumar, Ashutosh; Chatterjee, Sambarta; Nandi, Mintu; Dua, Arti

2016-08-28

Dynamic co-operativity in monomeric enzymes is characterized in terms of a non-Michaelis-Menten kinetic behaviour. The latter is believed to be associated with mechanisms that include multiple reaction pathways due to enzymatic conformational fluctuations. Recent advances in single-molecule fluorescence spectroscopy have provided new fundamental insights on the possible mechanisms underlying reactions catalyzed by fluctuating enzymes. Here, we present a bottom-up approach to understand enzyme turnover kinetics at physiologically relevant mesoscopic concentrations informed by mechanisms extracted from single-molecule stochastic trajectories. The stochastic approach, presented here, shows the emergence of dynamic co-operativity in terms of a slowing down of the Michaelis-Menten (MM) kinetics resulting in negative co-operativity. For fewer enzymes, dynamic co-operativity emerges due to the combined effects of enzymatic conformational fluctuations and molecular discreteness. The increase in the number of enzymes, however, suppresses the effect of enzymatic conformational fluctuations such that dynamic co-operativity emerges solely due to the discrete changes in the number of reacting species. These results confirm that the turnover kinetics of fluctuating enzyme based on the parallel-pathway MM mechanism switches over to the single-pathway MM mechanism with the increase in the number of enzymes. For large enzyme numbers, convergence to the exact MM equation occurs in the limit of very high substrate concentration as the stochastic kinetics approaches the deterministic behaviour.

Emergence of dynamic cooperativity in the stochastic kinetics of fluctuating enzymes

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

Kumar, Ashutosh; Chatterjee, Sambarta; Nandi, Mintu

Dynamic co-operativity in monomeric enzymes is characterized in terms of a non-Michaelis-Menten kinetic behaviour. The latter is believed to be associated with mechanisms that include multiple reaction pathways due to enzymatic conformational fluctuations. Recent advances in single-molecule fluorescence spectroscopy have provided new fundamental insights on the possible mechanisms underlying reactions catalyzed by fluctuating enzymes. Here, we present a bottom-up approach to understand enzyme turnover kinetics at physiologically relevant mesoscopic concentrations informed by mechanisms extracted from single-molecule stochastic trajectories. The stochastic approach, presented here, shows the emergence of dynamic co-operativity in terms of a slowing down of the Michaelis-Menten (MM) kineticsmore » resulting in negative co-operativity. For fewer enzymes, dynamic co-operativity emerges due to the combined effects of enzymatic conformational fluctuations and molecular discreteness. The increase in the number of enzymes, however, suppresses the effect of enzymatic conformational fluctuations such that dynamic co-operativity emerges solely due to the discrete changes in the number of reacting species. These results confirm that the turnover kinetics of fluctuating enzyme based on the parallel-pathway MM mechanism switches over to the single-pathway MM mechanism with the increase in the number of enzymes. For large enzyme numbers, convergence to the exact MM equation occurs in the limit of very high substrate concentration as the stochastic kinetics approaches the deterministic behaviour.« less

Major anion and cation fluxes from the Central SiberianPlateau watersheds with underlying permafrost

NASA Astrophysics Data System (ADS)

Kolosov, Roman R.; Prokushkin, Anatoly S.; Pokrovsky, Oleg S.

2016-11-01

The subarctic rivers of the Central Siberian Plateau have specific fed-characteristics due to the permafrost distribution and the active layer thawing dynamics. Two watersheds with different types of permafrost (from insular to continuous) are studied. Different data sources (Roshydromet and our own observations) are used for receiving anions’ (HCO3-, SO4 2-, Cl-) and cations’ (Ca2+, Mg2+) fluxes from the Nizhnyaya Tunguska river (1960-2011) and the Tembenchi river (1970-2011). The annual discharge of N. Tunguska for 1939-2011 is characterized by an increase of 0.3 km3/year/year, and for Tembenchi, 0.04 km3/year/year. The major part of the increase (about 60%) is due to spring flooding (May - June). The volume-weighted mean concentrations of major anions and cations in the N. Tunguska river water increased three times in the spring period (40.7 - 116.8 mg/l) and in the summer-fall period (74-212.9 mg/l). On the contrary, such concentrations decreased sharply during the winter mean water period. Due to these results, the total export of main anions and cations from the N. Tunguska river basin rose more than 4,5 times. Two possible reasons can be identified: 1) a water discharge increase of the Subarctic rivers (Peterson et al., 2002); 2) permafrost degradation induced by global climate warming (Frey and McClelland 2009).

Safety of the Transcranial Focal Electrical Stimulation via Tripolar Concentric Ring Electrodes for Hippocampal CA3 Subregion Neurons in Rats

PubMed Central

2017-01-01

Epilepsy is a neurological disorder that affects approximately one percent of the world population. Noninvasive electrical brain stimulation via tripolar concentric ring electrodes has been proposed as an alternative/complementary therapy for seizure control. Previous results suggest its efficacy attenuating acute seizures in penicillin, pilocarpine-induced status epilepticus, and pentylenetetrazole-induced rat seizure models and its safety for the rat scalp, cortical integrity, and memory formation. In this study, neuronal counting was used to assess possible tissue damage in rats (n = 36) due to the single dose or five doses (given every 24 hours) of stimulation on hippocampal CA3 subregion neurons 24 hours, one week, and one month after the last stimulation dose. Full factorial analysis of variance showed no statistically significant difference in the number of neurons between control and stimulation-treated animals (p = 0.71). Moreover, it showed no statistically significant differences due to the number of stimulation doses (p = 0.71) nor due to the delay after the last stimulation dose (p = 0.96). Obtained results suggest that stimulation at current parameters (50 mA, 200 μs, 300 Hz, biphasic, charge-balanced pulses for 2 minutes) does not induce neuronal damage in the hippocampal CA3 subregion of the brain. PMID:29065603

Safety of the Transcranial Focal Electrical Stimulation via Tripolar Concentric Ring Electrodes for Hippocampal CA3 Subregion Neurons in Rats.

PubMed

Mucio-Ramírez, Samuel; Makeyev, Oleksandr

2017-01-01

Epilepsy is a neurological disorder that affects approximately one percent of the world population. Noninvasive electrical brain stimulation via tripolar concentric ring electrodes has been proposed as an alternative/complementary therapy for seizure control. Previous results suggest its efficacy attenuating acute seizures in penicillin, pilocarpine-induced status epilepticus, and pentylenetetrazole-induced rat seizure models and its safety for the rat scalp, cortical integrity, and memory formation. In this study, neuronal counting was used to assess possible tissue damage in rats ( n = 36) due to the single dose or five doses (given every 24 hours) of stimulation on hippocampal CA3 subregion neurons 24 hours, one week, and one month after the last stimulation dose. Full factorial analysis of variance showed no statistically significant difference in the number of neurons between control and stimulation-treated animals ( p  = 0.71). Moreover, it showed no statistically significant differences due to the number of stimulation doses ( p  = 0.71) nor due to the delay after the last stimulation dose ( p  = 0.96). Obtained results suggest that stimulation at current parameters (50 mA, 200  μ s, 300 Hz, biphasic, charge-balanced pulses for 2 minutes) does not induce neuronal damage in the hippocampal CA3 subregion of the brain.

Improving Understanding of the Chemical Mechanism of Oil Recovery from Oil-Wet Carbonate Reservoirs: AN Experimental Approach

NASA Astrophysics Data System (ADS)

Purswani, P.; Karpyn, Z.

2017-12-01

Chemical tuning of injecting brine has found great success in improving oil recovery from oil-wet rocks. In particular, the importance of Mg2+, Ca2+, and SO42- ions has been identified as critical for incremental oil recovery via multi-ion exchange mechanism of wettability alteration. To improve understanding of this underlying mechanism and, to evaluate the individual contribution of these ions towards improving oil recovery, a series of waterflood experiments with varying ion composition were performed at 90 oC. Characterization techniques like zeta potential (ZP), contact angle measurements and trace element analysis were performed to evaluate the surface interactions taking place among the rock samples, brine solution, and the crude oil. ZP measurements highlight the affinity of Mg2+, Ca2+, and SO42- ions towards the rock surface in chemically tuned brines (CTBs), where, an increase in the magnitude of ZP was seen with an increase in the concentration of each of these ions. Oil recovery measurements showed an increase in oil recovery for all the CTBs compared to seawater. Relative permeability estimations and contact angle measurements showed corresponding trends of increasing water-wetness. Maximum recovery of 75.47% original oil in place (OOIP) was observed for the brine with increased Mg2+ ion concentration due to higher activity of Mg2+ ions. Lower recovery of 63.58% OOIP was seen for the brine with increased Ca2+ ion concentration due to lower activity of Ca2+ ions, and further lower recovery of 58.59% OOIP was seen for the brine with increased SO42- ion concentration due to the possible precipitation of these ions on the rock surface. These surface reactions were confirmed through the ionic analysis of the effluent brine during each waterflooding experiment. These results help understand the importance of chemical tuning of brines towards improving oil recovery and provides experimental insight into the chemical reactions that occur during this process.

Residues of chlortetracycline, doxycycline and sulfadiazine-trimethoprim in intestinal content and feces of pigs due to cross-contamination of feed.

PubMed

Peeters, Laura E J; Daeseleire, Els; Devreese, Mathias; Rasschaert, Geertrui; Smet, Annemieke; Dewulf, Jeroen; Heyndrickx, Marc; Imberechts, Hein; Haesebrouck, Freddy; Butaye, Patrick; Croubels, Siska

2016-09-20

Cross-contamination of feed with low concentrations of antimicrobials can occur at production, transport and/or farm level. Concerns are rising about possible effects of this contaminated feed on resistance selection in the intestinal microbiota. Therefore, an experiment with pigs was set up, in which intestinal and fecal concentrations of chlortetracycline (CTC), doxycycline (DOX) and sulfadiazine-trimethoprim (SDZ-TRIM) were determined after administration of feed containing a 3 % carry-over level of these antimicrobials. The poor oral bioavailability of tetracyclines resulted in rather high concentrations in cecal and colonic content and feces at steady-state conditions. A mean concentration of 10 mg/kg CTC and 4 mg/kg DOX in the feces was reached, which is higher than concentrations that were shown to cause resistance selection. On the other hand, lower mean levels of SDZ (0.7 mg/kg) and TRIM (< limit of detection of 0.016 mg/kg) were found in the feces, corresponding with the high oral bioavailability of SDZ and TRIM in pigs. The relation between the oral bioavailability and intestinal concentrations of the tested antimicrobials, may be of help in assessing the risks of cross-contaminated feed. However, future research is needed to confirm our results and to evaluate the effects of these detected concentrations on resistance selection in the intestinal microbiota of pigs.

Chlorinated and polycyclic aromatic hydrocarbons in riverine and estuarine sediments from Pearl River Delta, China.

PubMed

Mai, Bi-Xian; Fu, Jia-Mo; Sheng, Guo-Ying; Kang, Yue-Hui; Lin, Zheng; Zhang, Gan; Min, Yu-Shuan; Zeng, Eddy Y

2002-01-01

Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and estuarine sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine sediment samples range from 12 to 158 ng/g, dry weight, while those of PCBs range from 11 to 486 ng/g. The CPs concentrations of the estuarine sediment samples are in the range 6-1658 ng/g, while concentrations of PCBs are in the range 10-339 ng/g. Total PAH concentration ranges from 1168 to 21,329 ng/g in the riverine sediment samples, whereas the PAH concentration ranges from 323 to 14,812 ng/g in the sediment samples of the Estuary. Sediment samples of the Zhujiang River and Macao harbor around the Estuary show the highest concentrations of CPs, PCBs, and PAHs. Possible factors affecting the distribution patterns are also discussed based on the usage history of the chemicals, hydrologic condition, and land erosion due to urbanization processes. The composition of PAHs is investigated and used to assess petrogenic, combustion and naturally derived PAHs of the sediment samples of the Pearl River Delta. In addition, the concentrations of a number of organic compounds of the Pearl River Delta samples indicate that sediments of the Zhujiang river and Macao harbor are most likely to pose biological impairment.

Effects of acute and chronic exercise on the osmotic stability of erythrocyte membrane of competitive swimmers.

PubMed

Paraiso, Lara Ferreira; Gonçalves-E-Oliveira, Ana Flávia Mayrink; Cunha, Lucas Moreira; de Almeida Neto, Omar Pereira; Pacheco, Adriana Garcia; Araújo, Karinne Beatriz Gonçalves; Garrote-Filho, Mário da Silva; Bernardino Neto, Morun; Penha-Silva, Nilson

2017-01-01

This study aimed to evaluate the influence of acute and chronic exercise on erythrocyte membrane stability and various blood indices in a population consisting of five national-level male swimmers, over 18 weeks of training. The evaluations were made at the beginning and end of the 1st, 7th, 13th and 18th weeks, when volume and training intensity have changed. The effects manifested at the beginning of those weeks were considered due to chronic adaptations, while the effects observed at the end of the weeks were considered due to acute manifestations of the exercise load of that week. Acute changes resulting from the exercise comprised increases in creatine kinase activity (CK) and leukocyte count (Leu), and decrease in hematocrit (Ht) and mean corpuscular volume (MCV), at the end of the first week; increase in the activities of CK and lactate dehydrogenase (LDH), in the uric acid (UA) concentration and Leu count, at the end of the seventh week; increases in CK and LDH activities and in the mean corpuscular hemoglobin concentration (MCHC), at the end of the 13th week; and decrease in the value of the osmotic stability index 1/H50 and increases in the CK activity and platelets (Plt) count, at the end of the 18th week. Chronic changes due to training comprised increase in the values of 1/H50, CK, LDH, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), serum iron (Fe), MCV and Plt. Although acute training has resulted in decrease in the osmotic stability of erythrocytes, possibly associated with exacerbation of the oxidative processes during intense exercise, chronic training over 18 weeks resulted in increased osmotic stability of erythrocytes, possibly by modulation in the membrane cholesterol content by low and high density lipoproteins.

Intraperitoneal injections as a possible means of generating varied levels of methylmercury in the eggs of birds in field studies

USGS Publications Warehouse

Heinz, Gary H.; Hoffman, David J.; Klimstra, Jon D.; Stebbins, Katherine R.

2010-01-01

The ideal study of the effects of methylmercury on the reproductive success of a species of bird would be one in which eggs contained mercury concentrations ranging from controls to very heavily contaminated, all at the same site. Such a study cannot be realized at a mercury contaminated area or under laboratory conditions, but could be achieved by introducing methylmercury into breeding females and allowing them to deposit mercury in their eggs. Female mallards (Anas platyrhynchos) were intraperitoneally injected with solutions of methylmercury chloride dissolved in corn oil, propylene glycol, dimethyl sulfoxide, mineral oil, Olestra, Crisco, lard, hard paraffin, and a combination of hard and soft paraffin. In some cases, egg laying was delayed, either due to the solvent itself (in the case of Olestra, Crisco, and lard) or to the highest concentration of methylmercury chloride (500 μg/g) in some of the solvents. Mercury in eggs ranged from a control level (< 0.1 μg/g) to approximately 14 μg/g on a wet weight basis, which more than covers the range of concentrations reported in wild bird eggs. Mercury concentrations in a series of eggs from the same female declined mostly due to excretion of mercury in prior eggs and not because of the length of time since the injection. Intraperitoneal injections hold promise in field studies where one would like to study the reproductive effects of a wide range of methylmercury levels in the eggs of a wild bird and under the natural conditions that exist in the field.

Distribution and leaching characteristics of trace elements in ashes as a function of different waste fuels and incineration technologies.

PubMed

Saqib, Naeem; Bäckström, Mattias

2015-10-01

Impact of waste fuels (virgin/waste wood, mixed biofuel (peat, bark, wood chips) industrial, household, mixed waste fuel) and incineration technologies on partitioning and leaching behavior of trace elements has been investigated. Study included 4 grate fired and 9 fluidized boilers. Results showed that mixed waste incineration mostly caused increased transfer of trace elements to fly ash; particularly Pb/Zn. Waste wood incineration showed higher transfer of Cr, As and Zn to fly ash as compared to virgin wood. The possible reasons could be high input of trace element in waste fuel/change in volatilization behavior due to addition of certain waste fractions. The concentration of Cd and Zn increased in fly ash with incineration temperature. Total concentration in ashes decreased in order of Zn>Cu>Pb>Cr>Sb>As>Mo. The concentration levels of trace elements were mostly higher in fluidized boilers fly ashes as compared to grate boilers (especially for biofuel incineration). It might be attributed to high combustion efficiency due to pre-treatment of waste in fluidized boilers. Leaching results indicated that water soluble forms of elements in ashes were low with few exceptions. Concentration levels in ash and ash matrix properties (association of elements on ash particles) are crucial parameters affecting leaching. Leached amounts of Pb, Zn and Cr in >50% of fly ashes exceeded regulatory limit for disposal. 87% of chlorine in fly ashes washed out with water at the liquid to solid ratio 10 indicating excessive presence of alkali metal chlorides/alkaline earths. Copyright © 2015. Published by Elsevier B.V.

Multifactorial Effects on Different Types of Brain Cells Contribute to Ammonia Toxicity.

PubMed

Hertz, Leif; Song, Dan; Peng, Liang; Chen, Ye

2017-03-01

Effects of ammonia on astrocytes play a major role in hepatic encephalopathy, acute liver failure and other diseases caused by increased arterial ammonia concentrations (e.g., inborn errors of metabolism, drug or mushroom poisoning). There is a direct correlation between arterial ammonia concentration, brain ammonia level and disease severity. However, the pathophysiology of hyperammonemic diseases is disputed. One long recognized factor is that increased brain ammonia triggers its own detoxification by glutamine formation from glutamate. This is an astrocytic process due to the selective expression of the glutamine synthetase in astrocytes. A possible deleterious effect of the resulting increase in glutamine concentration has repeatedly been discussed and is supported by improvement of some pathologic effects by GS inhibition. However, this procedure also inhibits a large part of astrocytic energy metabolism and may prevent astrocytes from responding to pathogenic factors. A decrease of the already low glutamate concentration in astrocytes due to increased synthesis of glutamine inhibits the malate-aspartate shuttle and energy metabolism. A more recently described pathogenic factor is the resemblance between NH 4 + and K + in their effects on the Na + ,K + -ATPase and the Na + ,K + , 2 Cl - and water transporter NKCC1. Stimulation of the Na + ,K + -ATPase driven NKCC1 in both astrocytes and endothelial cells is essential for the development of brain edema. Na + ,K + -ATPase stimulation also activates production of endogenous ouabains. This leads to oxidative and nitrosative damage and sensitizes NKCC1. Administration of ouabain antagonists may accordingly have therapeutic potential in hyperammonemic diseases.

A quantitative comparison of simultaneous BOLD fMRI and NIRS recordings during functional brain activation

NASA Technical Reports Server (NTRS)

Strangman, Gary; Culver, Joseph P.; Thompson, John H.; Boas, David A.; Sutton, J. P. (Principal Investigator)

2002-01-01

Near-infrared spectroscopy (NIRS) has been used to noninvasively monitor adult human brain function in a wide variety of tasks. While rough spatial correspondences with maps generated from functional magnetic resonance imaging (fMRI) have been found in such experiments, the amplitude correspondences between the two recording modalities have not been fully characterized. To do so, we simultaneously acquired NIRS and blood-oxygenation level-dependent (BOLD) fMRI data and compared Delta(1/BOLD) (approximately R(2)(*)) to changes in oxyhemoglobin, deoxyhemoglobin, and total hemoglobin concentrations derived from the NIRS data from subjects performing a simple motor task. We expected the correlation with deoxyhemoglobin to be strongest, due to the causal relation between changes in deoxyhemoglobin concentrations and BOLD signal. Instead we found highly variable correlations, suggesting the need to account for individual subject differences in our NIRS calculations. We argue that the variability resulted from systematic errors associated with each of the signals, including: (1) partial volume errors due to focal concentration changes, (2) wavelength dependence of this partial volume effect, (3) tissue model errors, and (4) possible spatial incongruence between oxy- and deoxyhemoglobin concentration changes. After such effects were accounted for, strong correlations were found between fMRI changes and all optical measures, with oxyhemoglobin providing the strongest correlation. Importantly, this finding held even when including scalp, skull, and inactive brain tissue in the average BOLD signal. This may reflect, at least in part, the superior contrast-to-noise ratio for oxyhemoglobin relative to deoxyhemoglobin (from optical measurements), rather than physiology related to BOLD signal interpretation.

Ghrelin plasma concentration does not covary with energy demand in adult laying hens.

PubMed

Höhne, A; Schrader, L; Weigend, S; Petow, S

2017-10-01

The peptide hormone ghrelin is suggested to be involved in food intake regulation in young growing chicken. Whether ghrelin is involved in the regulation of energetic balance associated with laying performance in adult laying hens was studied by use of 4 chicken lines that differ in laying performance and phylogeny (4 lines; 16 hens per line). As housing conditions are also known to affect energy demand, half of the hens per line were housed in single cages and the other half of hens were maintained in a floor housing system. Plasma samples were collected at 17 to 19, 33 to 35, 49 to 51, and 72 wk of age and analyzed with a chicken ghrelin ELISA Kit. From caged hens, individual food consumption and laying performance additionally was recorded. Due to its function in growth and its relationship with ghrelin, also GH plasma concentrations were analyzed. Ghrelin concentrations did not differ between the 4 lines at any of the test periods (all P > 0.05). Ghrelin was negatively related to food consumption only in the growing period of the high-performing lines (both P < 0.0001). During this phase, floor-housed hens showed greater ghrelin concentrations compared with caged hens (P < 0.0001). Our results suggest that in adult layers ghrelin is not involved in regulating energy intake related to laying performance but rather seems to be related to body growth and housing condition before start of lay, the latter possibly due to differences in hens' behavioral activity. Copyright © 2017 Elsevier Inc. All rights reserved.

An outbreak of occupational asthma due to chromium and cobalt.

PubMed

Walters, G I; Moore, V C; Robertson, A S; Burge, C B S G; Vellore, A-D; Burge, P S

2012-10-01

Five metal turners employed by an aerospace manufacturer presented to the Birmingham Chest Clinic occupational lung disease unit. Four cases of occupational asthma (OA) due to chromium salt (3) and cobalt (1) were diagnosed by serial peak-expiratory flow measurements and specific inhalation challenge testing. To measure the extent of the outbreak and to provide epidemiological data to ascertain the aetiology. Participants answered a detailed, self-administered questionnaire, designed to detect occupational lung disease. Urine chromium and cobalt excretion, spirometry and exhaled nitric oxide measurements were taken. Those with possible, probable or definite non-OA or OA, after questionnaire, were invited to undertake two-hourly peak flow measurements and received specialist follow-up. A total of 62 workers (95% of workforce) participated. Sixty-one per cent of employees were working in higher metalworking fluid (MWF) exposure areas. Ninety per cent of workers had urinary chromium excretion indicating occupational exposure. Sixty-six per cent of workers reported active respiratory symptoms, although there were no significant differences between exposure groups. Two further workers with probable OA were identified and had significantly higher urinary chromium and cobalt concentration than asymptomatic controls. Eighteen cases of occupational rhinitis (OR) were identified, with significantly raised urinary chromium concentration compared with asymptomatic controls. Chromium salt and cobalt can be responsible for OA and OR in workers exposed to MWF aerosols. Onset of symptoms in those with positive specific challenges followed change in MWF brand. Workers with OA had increased urinary concentrations of chromium and cobalt, and those with OR had increased urinary concentrations of chromium.

Influence of seasonal and inter-annual hydro-meteorological variability on surface water fecal coliform concentration under varying land-use composition.

PubMed

St Laurent, Jacques; Mazumder, Asit

2014-01-01

Quantifying the influence of hydro-meteorological variability on surface source water fecal contamination is critical to the maintenance of safe drinking water. Historically, this has not been possible due to the scarcity of data on fecal indicator bacteria (FIB). We examined the relationship between hydro-meteorological variability and the most commonly measured FIB, fecal coliform (FC), concentration for 43 surface water sites within the hydro-climatologically complex region of British Columbia. The strength of relationship was highly variable among sites, but tended to be stronger in catchments with nival (snowmelt-dominated) hydro-meteorological regimes and greater land-use impacts. We observed positive relationships between inter-annual FC concentration and hydro-meteorological variability for around 50% of the 19 sites examined. These sites are likely to experience increased fecal contamination due to the projected intensification of the hydrological cycle. Seasonal FC concentration variability appeared to be driven by snowmelt and rainfall-induced runoff for around 30% of the 43 sites examined. Earlier snowmelt in nival catchments may advance the timing of peak contamination, and the projected decrease in annual snow-to-precipitation ratio is likely to increase fecal contamination levels during summer, fall, and winter among these sites. Safeguarding drinking water quality in the face of such impacts will require increased monitoring of FIB and waterborne pathogens, especially during periods of high hydro-meteorological variability. This data can then be used to develop predictive models, inform source water protection measures, and improve drinking water treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solid-phase microextraction for qualitative and quantitative determination of migrated degradation products of antioxidants in an organic aqueous solution.

PubMed

Burman, Lina; Albertsson, Ann-Christine; Höglund, Anders

2005-07-08

Low molecular weight aromatic substances may migrate out from plastic packaging to their contents, especially if they consist of organic aqueous solutions or oils. It is, therefore, extremely important to be able to identify and quantify any migrated substances in such solutions, even at very low concentrations. We have in this work investigated and evaluated the use of solid-phase microextraction for the specific task of extraction from an organic aqueous solution such as a simulated pharmaceutical solution consisting of 10 vol.% ethanol in water. The goal was furthermore to investigate the possibility of simultaneously identifying and quantifying the substances in spite of differences in their chemical structures. Methods were developed and evaluated for extraction both with direct sampling and with headspace sampling. Difficulties appeared due to the ethanol in the solution and the minute amounts of substances present. We have shown that a simultaneous quantification of migrated low molecular weight degradation products of antioxidants using only one fibre is possible if the extraction method and temperature are adjusted in relation to the concentration levels of the analytes. Comparions were made with solid-phase extraction.

Chemical segregation in metallic glass nanowires.

PubMed

Zhang, Qi; Li, Qi-Kai; Li, Mo

2014-11-21

Nanowires made of metallic glass have been actively pursued recently due to the superb and unique properties over those of the crystalline materials. The amorphous nanowires are synthesized either at high temperature or via mechanical disruption using focused ion beam. These processes have potential to cause significant changes in structure and chemical concentration, as well as formation of defect or imperfection, but little is known to date about the possibilities and mechanisms. Here, we report chemical segregation to surfaces and its mechanisms in metallic glass nanowires made of binary Cu and Zr elements from molecular dynamics simulation. Strong concentration deviation are found in the nanowires under the conditions similar to these in experiment via focused ion beam processing, hot imprinting, and casting by rapid cooling from liquid state. Our analysis indicates that non-uniform internal stress distribution is a major cause for the chemical segregation, especially at low temperatures. Extension is discussed for this observation to multicomponent metallic glass nanowires as well as the potential applications and side effects of the composition modulation. The finding also points to the possibility of the mechanical-chemical process that may occur in different settings such as fracture, cavitation, and foams where strong internal stress is present in small length scales.

Exogenous contamination of uranium in human scalp hair.

PubMed

Muikku, Maarit; Heikkinen, Tarja

2012-06-01

The use of human scalp hair as a bioindicator of occupational or environmental exposure has been the subject of some debate over the years. One problem is how to distinguish internal contamination from external contamination. In this study, possibility that elevated levels of natural uranium in human hair are partly due to the exogenously bound uranium from uranium-rich household water was tested. Hair samples from six adult volunteers were cut and then exposed externally to uranium by using washing water with highly elevated levels of natural uranium. After that, and before making the analysis using inductively coupled plasma mass spectrometry (ICP-MS), the samples were washed using two commonly used washing procedures in order to remove external contamination. No quantitative information was gained in the tests, but it was shown that the use of uranium-rich water when washing hair affects the uranium concentration in hair. Although the samples were cleaned according to widely used washing procedures before the analysis, the uranium concentrations in hair were about three orders of magnitude higher after the tests. The possibility of external contamination should be kept in mind, especially when considering hair as an excretion pathway for estimating internal dose.

Batch and Continuous Ultrasound Assisted Extraction of Boldo Leaves (Peumus boldus Mol.).

PubMed

Petigny, Loïc; Périno-Issartier, Sandrine; Wajsman, Joël; Chemat, Farid

2013-03-12

Vegetal extracts are widely used as primary ingredients for various products from creams to perfumes in the pharmaceutical, nutraceutic and cosmetic industries. Having concentrated and active extract is essential, as the process must extract as much soluble material as possible in a minimum time, using the least possible volume of solvent. The boldo leaves extract is of great interest for the industry as it holds a great anti-oxidant activity due to high levels of flavonoids and alkaloids such as boldine. Ultrasound Assisted Extraction (UAE) has been used to improve the efficiency of the plant extraction, reducing extraction time, increasing the concentration of the extract with the same amount of solvent and plant material. After a preliminary study, a response surface method has been used to optimize the extraction of soluble material from the plant. The results provided by the statistical analysis revealed that the optimized conditions were: sonication power 23 W/cm2 for 40 min and a temperature of 36 °C. The optimized parameters of the UAE provide a better extraction compared to a conventional maceration in terms of process time (30 min instead of 120 min), higher yield, more energy saving, cleanliness, safety and product quality.

Batch and Continuous Ultrasound Assisted Extraction of Boldo Leaves (Peumus boldus Mol.)

PubMed Central

Petigny, Loïc; Périno-Issartier, Sandrine; Wajsman, Joël; Chemat, Farid

2013-01-01

Vegetal extracts are widely used as primary ingredients for various products from creams to perfumes in the pharmaceutical, nutraceutic and cosmetic industries. Having concentrated and active extract is essential, as the process must extract as much soluble material as possible in a minimum time, using the least possible volume of solvent. The boldo leaves extract is of great interest for the industry as it holds a great anti-oxidant activity due to high levels of flavonoids and alkaloids such as boldine. Ultrasound Assisted Extraction (UAE) has been used to improve the efficiency of the plant extraction, reducing extraction time, increasing the concentration of the extract with the same amount of solvent and plant material. After a preliminary study, a response surface method has been used to optimize the extraction of soluble material from the plant. The results provided by the statistical analysis revealed that the optimized conditions were: sonication power 23 W/cm2 for 40 min and a temperature of 36 °C. The optimized parameters of the UAE provide a better extraction compared to a conventional maceration in terms of process time (30 min instead of 120 min), higher yield, more energy saving, cleanliness, safety and product quality. PMID:23481637

Multiple toxic doses of methamphetamine alter neurotensin concentrations in various region of the rat brain

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

Hanson, G.R.; Merchant, K.; Gibb, J.W.

1986-03-05

The authors have previously reported that multiple high doses of methamphetamine (METH) alter neuronal monoamine metabolism and release. Recently, Hokfelt et al. showed that neurotensin, a tridecapeptide, has neurotransmitter properties which may be involved with DA neuronal activity. In the present study they investigated the possible effects of METH on the CNS neurotensin system. Five doses of METH (15 mg/kg) were administered every 6 h; control and treated rats were sacrificed 18 h after the last dose and concentrations of neurotensin-like immuno-reactivity (NTLI) were measured by radioimmunoassay. NTLI was elevated 200-300% in the nucleus accumbens, neostriatum, and substantia nigra; 30-40%more » increases in NTLI were measured in the hippocampus and hypothalamus. No change was observed in amygdala, A-10 or periaqueductal gray. In contrast to the above measured areas, the frontal lobe and olfactory bulb showed decreases of 25-35%. These findings demonstrate that METH treatment alters the activities of several CNS neurotensin systems, possibly due to the influence of this drug on DA pathways. The variability in the type and magnitude of these responses suggests that DA and neurotensin systems interact by more than one mechanism.« less

On radon emanation as a possible indicator of crustal deformation

USGS Publications Warehouse

King, C.-Y.

1979-01-01

Radon emanation has been monitored in shallow capped holes by a Tracketch method along several active faults and in the vicinity of some volcanoes and underground nuclear explosions. The measured emanation shows large temporal variations that appear to be partly related to crustal strain changes. This paper proposes a model that may explain the observed tectonic variations in radon emanation, and explores the possibility of using radon emanation as an indicator of crustal deformation. In this model the emanation variation is assumed to be due to the perturbation of near-surface profile of radon concentration in the soil gas caused by a change in the vertical flow rate of the soil gas which, in turn, is caused by the crustal deformation. It is shown that, for a typical soil, a small change in the flow rate (3 ?? 10-4 cm sec-1) can effect a significant change (a factor of 2) in radon emanation detected at a fixed shallow depth (0.7 m). The radon concentration profile has been monitored at several depths at a selected site to test the model. The results appear to be in satisfactory agreement. ?? 1979.

Deoxycytidine Deaminase-Deficient Escherichia coli Strains Display Acute Sensitivity to Cytidine, Adenosine, and Guanosine and Increased Sensitivity to a Range of Antibiotics, Including Vancomycin

PubMed Central

Kang, Tina Manzhu; Yuan, Jessica; Zhou, Alice; Beppler, Casey

2014-01-01

We show here that deoxycytidine deaminase (DCD)-deficient mutants of Escherichia coli are hypersensitive to killing by exogenous cytidine, adenosine, or guanosine, whereas wild-type cells are not. This hypersensitivity is reversed by exogenous thymidine. The mechanism likely involves the allosteric regulation of ribonucleotide reductase and severe limitations of the dTTP pools, resulting in thymineless death, the phenomenon of cell death due to thymidine starvation. We also report here that DCD-deficient mutants of E. coli are more sensitive to a series of different antibiotics, including vancomycin, and we show synergistic killing with the combination of vancomycin and cytidine. One possibility is that a very low, subinhibitory concentration of vancomycin enters Gram-negative cells and that this concentration is potentiated by chromosomal lesions resulting from the thymineless state. A second possibility is that the metabolic imbalance resulting from DCD deficiency affects the assembly of the outer membrane, which normally presents a barrier to drugs such as vancomycin. We consider these findings with regard to ideas of rendering Gram-negative bacteria sensitive to drugs such as vancomycin. PMID:24633874

Fractal pharmacokinetics.

PubMed

Pereira, Luis M

2010-06-01

Pharmacokinetics (PK) has been traditionally dealt with under the homogeneity assumption. However, biological systems are nowadays comprehensively understood as being inherently fractal. Specifically, the microenvironments where drug molecules interact with membrane interfaces, metabolic enzymes or pharmacological receptors, are unanimously recognized as unstirred, space-restricted, heterogeneous and geometrically fractal. Therefore, classical Fickean diffusion and the notion of the compartment as a homogeneous kinetic space must be revisited. Diffusion in fractal spaces has been studied for a long time making use of fractional calculus and expanding on the notion of dimension. Combining this new paradigm with the need to describe and explain experimental data results in defining time-dependent rate constants with a characteristic fractal exponent. Under the one-compartment simplification this strategy is straightforward. However, precisely due to the heterogeneity of the underlying biology, often at least a two-compartment model is required to address macroscopic data such as drug concentrations. This simple modelling step-up implies significant analytical and numerical complications. However, a few methods are available that make possible the original desideratum. In fact, exploring the full range of parametric possibilities and looking at different drugs and respective biological concentrations, it may be concluded that all PK modelling approaches are indeed particular cases of the fractal PK theory.

Is reducing variability of blood glucose the real but hidden target of intensive insulin therapy?

PubMed

Egi, Moritoki; Bellomo, Rinaldo; Reade, Michael C

2009-01-01

Since the first report that intensive insulin therapy reduced mortality in selected surgical critically ill patients, lowering of blood glucose levels has been recommended as a means of improving patient outcomes. In this initial Leuven trial, blood glucose control by protocol using insulin was applied to 98.7% of patients in the intensive group but to only 39.2% (P < 0.0001) of patients in the control group. If appropriately applied, such protocols should decrease both the mean blood glucose concentration and its variability (variation of blood glucose concentration). Thus, it is logically possible that the benefit of intensive insulin therapy in the first Leuven trial was due to a decrease in mean glucose levels, a decrease in their variability, or both. Several recent studies have confirmed significant associations between variability of blood glucose levels and patient outcomes. Decreasing the variability of blood glucose levels might be an important dimension of glucose management, a possible mechanism by which an intensive insulin protocol exerts its putative beneficial effects, and an important goal of glucose management in the intensive care unit. Clinicians need to be aware of this controversy when considering the application of intensive insulin therapy and interpreting future trials.

Eaves-dropping on plant volatiles by a specialist moth: significance of ratio and concentration

USDA-ARS?s Scientific Manuscript database

Volatile signals mediate many multitrophic interactions, some due to coevolution and others due to eavesdropping, but the role of specific concentrations and ratios has been controversial and difficult to test due to methodological limitations. We investigated the role of ratio and concentration usi...

Structure Formation in Salt-Free Solutions of Amphiphilic Sulfonated Polyelectrolytes

NASA Astrophysics Data System (ADS)

Bockstaller, Michael; Koehler, Werner

2000-03-01

Self-assembled systems have long attracted attention due to their practical importance in many technical and biological fields. Dodecyl-substituted poly(para-phenylen)sulfonates (abbreviated PPPS) are highly charged polyelectrolytes which in the uncharged state have been investigated extensively and an intrinsic persistence length of 15 nm has been reported. Due to their hydrophobic side chains, PPPS are compatible with water only as micellar aggregates and tend to form supramolecular structures even at concentrations as low as 10-5mol_mon.units/l. Because of the rodlike conformation of PPPS, this self-assembly leads to aggregates of anisotropic shape. Therefore, depolarized light scattering was employed to yield complementary information about structure and dynamics of these complex fluids. Aqueous solutions of PPPS at room temperature undergo a structural transition at a critical concentration of c_crit.=0.016 g/l. This transition is characterized by a strong increase of scattered intensity in forward direction and dynamic depolarized scattering. Above c_crit. the cylindrical micelles (L=310 nm, d=3.1 nm, N_radial=12) self assembly into large ellipsoidal clusters of size in the μ m range. Due to the strong increase of depolarized scattered intensity there has to be a preferential orientation of the micelles inside those clusters, which thus represent a lyotropic mesophase. By combining static and dynamic light scattering for the low q-range as well as small angle x-ray scattering for the higher q-range it is possible to determine size and shape of each aggregation step. Decreasing the molecular weight of the PPPS has profound influence on the micellar length and hence on c_crit. which is close to the overlap concentration (c ~ 1/L^3) allowing for the observation of the polyelectrolyte effect.

A physical mechanism of cancer heterogeneity

NASA Astrophysics Data System (ADS)

Chen, Cong; Wang, Jin

2016-02-01

We studied a core cancer gene regulatory network motif to uncover possible source of cancer heterogeneity from epigenetic sources. When the time scale of the protein regulation to the gene is faster compared to the protein synthesis and degradation (adiabatic regime), normal state, cancer state and an intermediate premalignant state emerge. Due to the epigenetics such as DNA methylation and histone remodification, the time scale of the protein regulation to the gene can be slower or comparable to the protein synthesis and degradation (non-adiabatic regime). In this case, many more states emerge as possible phenotype alternations. This gives the origin of the heterogeneity. The cancer heterogeneity is reflected from the emergence of more phenotypic states, larger protein concentration fluctuations, wider kinetic distributions and multiplicity of kinetic paths from normal to cancer state, higher energy cost per gene switching, and weaker stability.

Electrical Properties of Bismuth/Lithium-Cosubstituted Strontium Titanate Ceramics

NASA Astrophysics Data System (ADS)

Alkathy, Mahmoud. S.; James Raju, K. C.

2018-03-01

Sr(1-x)(Bi,Li) x TiO3 compound was prepared via a solid-state reaction route with microwave heating of the starting materials. X-ray diffraction analysis revealed pure perovskite phase without formation of any secondary phases. The electrical conductivity was studied as a function of temperature and frequency. The experimental results indicate that the alternating-current (AC) conductivity increased with frequency, following the Jonscher power law. To interpret the possible mechanism for electrical conduction, the correlated barrier hopping model was applied. The effect of temperature and the Bi/Li concentration on the electrical resistivity was studied. The results showed that the electrical resistivity decreased with increasing temperature, which could be due to increased thermal energy of electrons. Also, the electrical resistivity decreased with increase in the amount of Bi and Li, which could be due to increased concentration of structural defects, which could increase the number of either electrons or holes available for conduction. A single semicircular arc corresponding to a single relaxation process was observed for all the investigated ceramics, suggesting a grain contribution to the total resistance in these materials. Arrhenius plots were used to obtain the activation energy for the samples.

Levofloxacin for the treatment of respiratory tract infections.

PubMed

Torres, Antoni; Liapikou, Adamantia

2012-06-01

Fluoroquinolone use has dramatically increased since the introduction of the first respiratory fluoroquinolone in the late 1990s. Levofloxacin , like other fluoquinolones, is a potent antibiotic, due to high levels of susceptibility among Gram-negative, Gram-positive (including penicillin-resistant strains of Streptococcus pneumonia) and atypical pathogens. Levofloxacin is recommended for the treatment of community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP) and in the management of acute exacerbations of chronic bronchitis (AECB). Levofloxacin demonstrates good safety, bioavailability and tissue penetration, thus maintaining adequate concentrations at the site of infection. High-dose (750 mg), short-course (5 days) therapy regimens may offer improved treatment, especially in HAP, due to higher drug concentrations, increased adherence and the potential to reduce the development of resistance. This article covers medical literature published in any language since 1990 until November 2011, on 'levofloxacin', identified using PubMed and MEDLINE. The search terms used were 'levofloxacin' and 'community acquired pneumonia', 'hospital pneumonia' or 'AECB'. Levofloxacin is a valuable antimicrobial agent and an optimal treatment option for AECB, CAP (as a monotherapy) and HAP (as combination therapy at a high-dose regimen). Its improved bioavailability and safety profile makes the possibility of shorter hospital stays a reality.

[Need for occupational and environmental allergology in occupational health - the 45th Japanese society of Occupational and Environmental Allergy Annual Meeting 2014 in Fukuoka].

PubMed

Kishikawa, Reiko; Oshikawa, Chie

2014-12-01

The 45th Japanese Society of Occupational and Environmental Allergy (OEA) Annual Meeting 2014 was held in Fukuoka city in conjunction with a technical course for occupational health physicians to learn occupational and environmental diseases more deeply. Allergic reaction due to low concentrations of chemical and biological materials is important in toxicological diseases due to highly concentrated chemical materials in the field of occupational and environmental medicine. In this paper we describe the activities of the OEA, which was established in 1970 and has completely cured patients with severe occupational asthma, such as the regional Konjac asthma in Gunma prefecture and Sea Squirt asthma in Hiroshima prefecture. Regard for the occupational environment will prevent the onset and/or exacerbation of allergic occupational disease in individual employees with allergy. Occupational cancer of the bile duct and asbestosis are also current, serious issues that should be resolved as soon as possible. It is desirable for the occupational health physician to have a large stock of knowledge about toxicological and allergic diseases in various occupational settings to maintain the health and safety of workers.

Toxic Metals Enrichment in the Surficial Sediments of a Eutrophic Tropical Estuary (Cochin Backwaters, Southwest Coast of India)

PubMed Central

Martin, G. D.; George, Rejomon; Shaiju, P.; Muraleedharan, K. R.; Nair, S. M.; Chandramohanakumar, N.

2012-01-01

Concentrations and distributions of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surficial sediments of the Cochin backwaters were studied during both monsoon and pre-monsoon periods. Spatial variations were in accordance with textural charaterstics and organic matter content. A principal component analysis distinguished three zones with different metal accumulation capacity: (i) highest levels in north estuary, (ii) moderate levels in central zone, and (iii) lowest levels in southern part. Trace metal enrichments are mainly due to anthropogenic contribution of industrial, domestic, and agricultural effluents, whose effect is enhanced by settling of metals due to organic flocculation and inorganic precipitation associated with salinity changes. Enrichments factors using Fe as a normalizer showed that metal contamination was the product of anthropogenic activities. An assessment of degree of pollution-categorized sediments as moderately polluted with Cu and Pb, moderately-to-heavily polluted with Zn, and heavily-to-extremely polluted with Cd. Concentrations at many sites largely exceed NOAA ERL (e.g., Cu, Cr, and Pb) or ERM (e.g., Cd, Ni, and Zn). This means that adverse effects for benthic organisms are possible or even highly probable. PMID:22645488

Electrical Properties of Bismuth/Lithium-Cosubstituted Strontium Titanate Ceramics

NASA Astrophysics Data System (ADS)

Alkathy, Mahmoud. S.; James Raju, K. C.

2018-07-01

Sr(1- x)(Bi,Li) x TiO3 compound was prepared via a solid-state reaction route with microwave heating of the starting materials. X-ray diffraction analysis revealed pure perovskite phase without formation of any secondary phases. The electrical conductivity was studied as a function of temperature and frequency. The experimental results indicate that the alternating-current (AC) conductivity increased with frequency, following the Jonscher power law. To interpret the possible mechanism for electrical conduction, the correlated barrier hopping model was applied. The effect of temperature and the Bi/Li concentration on the electrical resistivity was studied. The results showed that the electrical resistivity decreased with increasing temperature, which could be due to increased thermal energy of electrons. Also, the electrical resistivity decreased with increase in the amount of Bi and Li, which could be due to increased concentration of structural defects, which could increase the number of either electrons or holes available for conduction. A single semicircular arc corresponding to a single relaxation process was observed for all the investigated ceramics, suggesting a grain contribution to the total resistance in these materials. Arrhenius plots were used to obtain the activation energy for the samples.

Enhanced primary treatment of concentrated black water and kitchen residues within DESAR concept using two types of anaerobic digesters.

PubMed

Kujawa-Roeleveld, K; Elmitwalli, T; Zeeman, G

2006-01-01

Anaerobic digestion of concentrated domestic wastewater streams--black or brown water, and solid fraction of kitchen waste is considered as a core technology in a source separation based sanitation concept (DESAR--decentralised sanitation and reuse). A simple anaerobic digester can be implemented for an enhanced primary treatment or, in some situations, as a main treatment. Two reactor configurations were extensively studied; accumulation system (AC) and UASB septic tank at 15, 20 and 25 degrees C. Due to long retention times in an AC reactor, far stabilisation of treated medium can be accomplished with methanisation up to 60%. The AC systems are the most suitable to apply when the volume of waste to be treated is minimal and when a direct reuse of a treated medium in agriculture is possible. Digested effluent contains both liquid and solids. In a UASB septic tank, efficient separation of solids and liquid is accomplished. The total COD removal was above 80% at 25 degrees C. The effluent contains COD and nutrients, mainly in a soluble form. The frequency of excess sludge removal is low and sludge is well stabilised due to a long accumulation time.

Trace element geochemistry in archaeological sites.

PubMed

Jenkins, D A

1989-06-01

Man can leave a geochemical imprint on an archaeological site in several ways. In common with other components of the biosphere, there is a selective enrichment of elements in his body tissues which, upon death and burial, may lead to detectable anomalies. Of elements concentrated in this way P is the most obvious, but Sn could be another possibility worth further investigation. There has been particular geochemical impact due to the progressive use of such metals as Ag, Au, Cu, Pb and Zn during successive cultural stages. Anomalies may thus arise due to recognisable transported ore, slags or artefacts, although there has also often been cryptic redispersion of the metals within a site. Charcoal is one of the commoner finds during excavations, and it has the ability to adsorb and concentrate metals progressively from percolating solutions since the time of its burial: with careful interpretation its analysis may thus provide a valuable historical record, as is illustrated by material from several sites in North Wales. Providing care is taken to interpret results in their particular geochemical and pedochemical context, trace element analysis may thus offer a useful insight into the history of man's activities in an archaeological site.

Hydroxyapatite/poly(epsilon-caprolactone) composite coatings on hydroxyapatite porous bone scaffold for drug delivery.

PubMed

Kim, Hae-Won; Knowles, Jonathan C; Kim, Hyoun-Ee

2004-01-01

Hydroxyapatite (HA) porous scaffold was coated with HA and polycaprolactone (PCL) composites, and antibiotic drug tetracycline hydrochloride was entrapped within the coating layer. The HA scaffold obtained by a polymeric reticulate method, possessed high porosity ( approximately 87%) and controlled pore size (150-200 microm). Such a well-developed porous structure facilitated usage in a drug delivery system due to its high surface area and blood circulation efficiency. The PCL polymer, as a coating component, was used to improve the brittleness and low strength of the HA scaffold, as well to effectively entrap the drug. To improve the osteoconductivity and bioactivity of the coating layer, HA powder was hybridized with PCL solution to make the HA-PCL composite coating. With alteration in the coating concentration and HA/PCL ratio, the morphology, mechanical properties, and biodegradation behavior were investigated. Increasing the concentration rendered the stems thicker and some pores to be clogged; as well increasing the HA/PCL ratio made the coating surface be rough due to the large amount of HA particles. However, for all concentrations and compositions, uniform coatings were formed, i.e., with the HA particles being dispersed homogeneously in the PCL sheet. With the composite coating, the mechanical properties, such as compressive strength and elastic modulus were improved by several orders of magnitude. These improvements were more significant with thicker coatings, while little difference was observed with the HA/PCL ratio. The in vitro biodegradation of the composite coatings in the phosphate buffered saline solution increased linearly with incubation time and the rate differed with the coating concentration and the HA/PCL ratio; the higher concentration and HA amount caused the increased biodegradation. At short period (<2 h), about 20-30% drug was released especially due to free drug at the coating surface. However, the release rate was sustained for prolonged periods and was highly dependent on the degree of coating dissolution, suggesting the possibility of a controlled drug release in the porous scaffold with HA+PCL coating.

Measurements of Turbulent Fluxes over Sea Ice Region in the Sea of Okhotsk.

NASA Astrophysics Data System (ADS)

Fujisaki, A.; Yamaguchi, H.; Toyota, T.; Futatsudera, A.; Miyanaga, M.

2007-12-01

The measurements of turbulent fluxes over sea ice area were done in the southern part of the Sea of Okhotsk, during the cruises of the ice-breaker P/V 'Soya' in 2000-2005. The air-ice drag coefficients CDN were 3.57×10-3 over small floes \\left(diameter:φ=20- 100m\\right), 3.38×10-3 over medium floes \\left(φ=100-500m\\right), and 2.12×10-3 over big floes \\left( φ=500m-2km\\right), which showed a decrease with the increase of floe size. This is because the smaller floes contribue to the roughness of sea-ice area by their edges more than the larger ones. The average CDN values showed a gradual upslope with ice concentration, which is simply due to the rougher surface of sea ice than that of open water, while they showed a slight decline at ice concentration 100%, which is possibly due to the lack of freeboard effect of lateral side of floes. We also compared the relation between the roughness length zM and the friction velocity u* with the model developed in the previous study. The zM-u* relation well corresponded with the model results, while the range of zM we obtained was larger than those obtained at the Ice Station Weddell and during the Surface Heat Budget of the Arctic Ocean project. The sensible heat transfer coefficients CHN were 1.35×10-3 at 80-90% ice concentration, and 0.95×10-3 at 100% ice concentration, which are comparable with the results of the past reaserches. On the other hand, we obtained a maximum CHN value of 2.39×10-3at 20-50% ice concentration, and 2.35×10-3 over open water, which are more than twice as the typical value of 1.0×10-3 over open water. These large CHN values are due to the significant upward sensible heat flux during the measurements.

Trace elements and diabetes: Assessment of levels in tears and serum.

PubMed

Cancarini, A; Fostinelli, J; Napoli, L; Gilberti, M E; Apostoli, P; Semeraro, F

2017-01-01

Tear film is critical for the well-being and homeostasis of the ocular surface. Although the composition of the tear film is well known, the composition of metallic elements have yet to be analysed. Despite trace elements metabolism has been reported to play a role in the pathogenesis of diabetes mellitus, a metabolic disease that affects several aspects of homeostasis, little is known in the literature regarding concentration and possible variation of metallic elements in tear film. We studied the concentrations of several essential and non-essential metallic elements in the tear fluid and serum of patients with type II diabetes mellitus and a group of non-diabetic controls. Serum and tear fluid were collected from 97 patients: 47 type II diabetic patients and 50 non-diabetic controls. Regarding tear film, there were statistically significant differences in Zinc, Chrome, Cobalt, Manganese, Barium, and Lead between groups; the values of all metallic elements were found to be statistically significant higher in patients with mellitus type II diabetes. Regarding serum values there was a statistically significant difference in Chrome, Cobalt, and Selenium values; the concentrations of Chrome and Cobalt were higher in the control group, while Selenium concentration was higher in diabetic patients. In patients with type II diabetes, metal elements with higher concentrations in tears compared to serum were: Lead, Barium, Manganese, Cobalt, and Chrome. In the control group, the metal elements with the highest concentration in tear film compared to serum were Chrome, Manganese, Barium, and Lead. In this study, we attempted to evaluate the possible effect of a disease, such as diabetes, on the metabolism of metallic elements. Although our evidence was very interesting, it is probably limited in its accuracy due to the fact that individuals in the control group harboured ocular pathologies. This work lays the foundation for future studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development and validation of an UPLC-MS/MS method for the quantification of tamoxifen and its main metabolites in human scalp hair.

PubMed

Drooger, Jan C; Jager, Agnes; Lam, Mei-Ho; den Boer, Mathilda D; Sleijfer, Stefan; Mathijssen, Ron H J; de Bruijn, Peter

2015-10-10

The aim of this study was to validate an earlier developed high-performance highly sensitive ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method for quantification of tamoxifen and its three main metabolites (N-desmethyl-tamoxifen, 4-hydroxy-tamoxifen and 4-hydroxy-N-desmethyl-tamoxifen) in scalp hair. This non-invasive method might, by segmental analysis of hair, be useful in the determination of the concentration of drugs and its metabolites over time, which can be used to study a wide variety of clinical relevant questions. Hair samples (150-300 hair strands, cut as close to the scalp as possible from the posterior vertex region of the head) were collected from female patients taking tamoxifen 20mg daily (n=19). The analytes were extracted using a liquid-liquid extraction procedure with carbonate buffer at pH 8.8 and a mixture of n-hexane/isopropranol method, followed by UPLC-MS/MS chromatography, based on an earlier validated method. The calibration curves were linear in the range of 1.00-200 pmol for tamoxifen and N-desmethyl-tamoxifen, with lower limit of quantitation of 1.00 pmol and 0.100-20.0 pmol with lower limit of quantitation of 0.100 pmol for endoxifen and 4-hydroxy-tamoxifen. Assay performance was fair with a within-run and between-run variability less than 9.24 at the three quality control samples and less than 15.7 for the lower limit of quantitation. Importantly, a steep linear decline was observed from distal to proximal hair segments. Probably, this is due to UV exposure as we showed degradation of tamoxifen and its metabolites after exposure to UV-light. Furthermore, higher concentrations of tamoxifen were found in black hair samples compared to blond and brown hair samples. We conclude that measurement of the concentration of tamoxifen and its main metabolites in hair is possible, with the selective, sensitive, accurate and precise UPLC-MS/MS method. However, for tamoxifen, it seems not possible to determine exposure over time with segmental analysis of hair, probably largely due to the effect of UV irradiation. Further research should therefore focus on quantification of other anticancer drugs, in segmented scalp hair, that are less sensitive to UV irradiation. Copyright © 2015 Elsevier B.V. All rights reserved.

Factors Influencing the Flavour of Bovine Milk and Cheese from Grass Based versus Non-Grass Based Milk Production Systems

PubMed Central

Faulkner, Hope; Clarke, Holly J.; O’Sullivan, Maurice G.; Kerry, Joseph P.

2018-01-01

There has been a surge in interest in relation to differentiating dairy products derived from pasture versus confined systems. The impact of different forage types on the sensory properties of milk and cheese is complex due to the wide range of on farm and production factors that are potentially involved. The main effect of pasture diet on the sensory properties of bovine milk and cheese is increased yellow intensity correlated to β-carotene content, which is a possible biomarker for pasture derived dairy products. Pasture grazing also influences fat and fatty acid content which has been implicated with texture perception changes in milk and cheese and increased omega-3 fatty acids. Changes in polyunsaturated fatty acids in milk and cheese due to pasture diets has been suggested may increase susceptibility to lipid oxidation but does not seem to be an issue to due increased antioxidants and the reducing environment of cheese. It appears that pasture derived milk and cheese are easier to discern by trained panellists and consumers than milk derived from conserved or concentrate diets. However, milk pasteurization, inclusion of concentrate in pasture diets, cheese ripening time, have all been linked to reducing pasture dietary effects on sensory perception. Sensory evaluation studies of milk and cheese have, in general, found that untrained assessors who best represent consumers appear less able to discriminate sensory differences than trained assessors and that differences in visual and textural attributes are more likely to be realized than flavour attributes. This suggests that sensory differences due to diet are often subtle. Evidence supports the direct transfer of some volatiles via inhalation or ingestion but more so with indirect transfer post rumen metabolism dietary components. The impact of dietary volatiles on sensory perception of milk and dairy products obviously depends upon their concentration and odour activity, however very little quantitative studies have been carried out to date. Some studies have highlighted potential correlation of pasture with enhanced “barny” or “cowy” sensory attributes and subsequently linked these to accumulation of p-cresol from the metabolism of β-carotene and aromatic amino acids or possibly isoflavones in the rumen. p-Cresol has also been suggested as a potential biomarker for pasture derived dairy products. Other studies have linked terpenes to specific sensory properties in milk and cheese but this only appears to be relevant in milk and cheese derived from unseeded wild pasture where high concentrations accumulate, as their odour threshold is quite high. Toluene also a product of β-carotene metabolism has been identified as a potential biomarker for pasture derived dairy products but it has little impact on sensory perception due to its high odour threshold. Dimethyl sulfone has been linked to pasture diets and could influence sensory perception as its odour threshold is low. Other studies have linked the presence of maize and legumes (clover) in silage with adverse sensory impacts in milk and cheese. Considerably more research is required to define key dietary related impacts on the flavour of milk and cheese. PMID:29534042

Using spatial-stream-network models and long-term data to understand and predict dynamics of faecal contamination in a mixed land-use catchment.

PubMed

Neill, Aaron James; Tetzlaff, Doerthe; Strachan, Norval James Colin; Hough, Rupert Lloyd; Avery, Lisa Marie; Watson, Helen; Soulsby, Chris

2018-01-15

An 11year dataset of concentrations of E. coli at 10 spatially-distributed sites in a mixed land-use catchment in NE Scotland (52km 2 ) revealed that concentrations were not clearly associated with flow or season. The lack of a clear flow-concentration relationship may have been due to greater water fluxes from less-contaminated headwaters during high flows diluting downstream concentrations, the importance of persistent point sources of E. coli both anthropogenic and agricultural, and possibly the temporal resolution of the dataset. Point sources and year-round grazing of livestock probably obscured clear seasonality in concentrations. Multiple linear regression models identified potential for contamination by anthropogenic point sources as a significant predictor of long-term spatial patterns of low, average and high concentrations of E. coli. Neither arable nor pasture land was significant, even when accounting for hydrological connectivity with a topographic-index method. However, this may have reflected coarse-scale land-cover data inadequately representing "point sources" of agricultural contamination (e.g. direct defecation of livestock into the stream) and temporal changes in availability of E. coli from diffuse sources. Spatial-stream-network models (SSNMs) were applied in a novel context, and had value in making more robust catchment-scale predictions of concentrations of E. coli with estimates of uncertainty, and in enabling identification of potential "hot spots" of faecal contamination. Successfully managing faecal contamination of surface waters is vital for safeguarding public health. Our finding that concentrations of E. coli could not clearly be associated with flow or season may suggest that management strategies should not necessarily target only high flow events or summer when faecal contamination risk is often assumed to be greatest. Furthermore, we identified SSNMs as valuable tools for identifying possible "hot spots" of contamination which could be targeted for management, and for highlighting areas where additional monitoring could help better constrain predictions relating to faecal contamination. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of high-resolution GRAMM-GRAL (v15.12/v14.8) NOx simulations over the city of Zürich, Switzerland

NASA Astrophysics Data System (ADS)

Berchet, Antoine; Zink, Katrin; Oettl, Dietmar; Brunner, Jürg; Emmenegger, Lukas; Brunner, Dominik

2017-09-01

Hourly NOx concentrations were simulated for the city of Zürich, Switzerland, at 10 m resolution for the years 2013-2014. The simulations were generated with the nested mesoscale meteorology and micro-scale dispersion model system GRAMM-GRAL (versions v15.12 and v14.8) by applying a catalogue-based approach. This approach was specifically designed to enable long-term city-wide building-resolving simulations with affordable computation costs. It relies on a discrete set of possible weather situations and corresponding steady-state flow and dispersion patterns that are pre-computed and then matched hourly with actual meteorological observations. The modelling system was comprehensively evaluated using eight sites continuously monitoring NOx concentrations and 65 passive samplers measuring NO2 concentrations on a 2-weekly basis all over the city. The system was demonstrated to fulfil the European Commission standards for air pollution modelling at nearly all sites. The average spatial distribution was very well represented, despite a general tendency to overestimate the observed concentrations, possibly due to a crude representation of traffic-induced turbulence and to underestimated dispersion in the vicinity of buildings. The temporal variability of concentrations explained by varying emissions and weather situations was accurately reproduced on different timescales. The seasonal cycle of concentrations, mostly driven by stronger vertical dispersion in summer than in winter, was very well captured in the 2-year simulation period. Short-term events, such as episodes of particularly high and low concentrations, were detected in most cases by the system, although some unrealistic pollution peaks were occasionally generated, pointing at some limitations of the steady-state approximation. The different patterns of the diurnal cycle of concentrations observed in the city were generally well captured as well. The evaluation confirmed the adequacy of the catalogue-based approach in the context of city-scale air pollution modelling. The ability to reproduce not only the spatial gradients but also the hourly temporal variability over multiple years makes the model system particularly suitable for investigating individualized air pollution exposure in the city.

Influence of UV irradiation on the toxicity of phenylurea herbicides using Microtox test.

PubMed

Bonnemoy, F; Lavédrine, B; Boulkamh, A

2004-02-01

Halogenated phenylurea herbicides are not very toxic by themselves to animals, but their exposure to UV light may significantly increase the toxicity of their solutions. Absorption of light may indeed induce a phototransformation of the herbicide with a possible formation of more toxic intermediate photoproducts. Fortunately in environmental conditions photolysis is usually slow and photoproducts do not accumulate appreciably. Microtox was used for the evaluation of the toxicity of the crude irradiated solutions of some phenylurea herbicides. The sharp initial increase of toxicity shown by metobromuron solutions is mainly due to intermediate photoproducts which rapidly disappear. In the case of diuron and metoxuron toxicity is due to minor photoproducts and it does not disappear so rapidly. Hence the decrease of herbicide concentration is not necessarily associated to a lower toxicity of the solution.

Relationship of 2,3-diphosphoglycerate and 2,3-diphosphoglycerate mutase in various mammals.

PubMed

Chemtob, S; Gibb, W; Bard, H

1980-01-01

To investigate a possible mechanism involved in the regulation of 2,3-diphosphoglycerate (2,3-DPG) synthesis, 2,3-DPG mutase (DPGM) was measured in different mammals presenting large differences in 2,3-DPG concentration between fetal, neonatal and adult life to see the activity of this enzyme, necessary for 2,3-DPG synthesis, was related to the levels of 2,3-DPG. The data demonstrated that the minimal levels of 2,3-DPG in the adult sheep are likely due to the very low levels of DPGM. Also these findings show that the increases in 2,3-DPG levels, found in the newborn sheep during the 1st week of life, in adult rabbit and guinea pig when compared with their fetuses, are not due to an increase in levels of the DPGM.

Greenhouse effects due to man-made perturbations of trace gases

NASA Technical Reports Server (NTRS)

Wang, W. C.; Yung, Y. L.; Lacis, A. A.; Mo, T.; Hansen, J. E.

1976-01-01

Nitrous oxide, methane, ammonia, and a number of other trace constituents of the earth's atmosphere have infrared absorption bands in the spectral range from 7 to 14 microns. Despite their small amounts, these gases can have a significant effect on the thermal structure of the atmosphere by transmitting most of the thermal radiation from the earth's surface to the lower atmosphere. In the present paper, this greenhouse effect is computed for a number of trace gases. The nature and climatic implications of possible changes in the concentrations of N2O, CH4, NH3, and HNO3 are discussed.

Workspaces in the Semantic Web

NASA Technical Reports Server (NTRS)

Wolfe, Shawn R.; Keller, RIchard M.

2005-01-01

Due to the recency and relatively limited adoption of Semantic Web technologies. practical issues related to technology scaling have received less attention than foundational issues. Nonetheless, these issues must be addressed if the Semantic Web is to realize its full potential. In particular, we concentrate on the lack of scoping methods that reduce the size of semantic information spaces so they are more efficient to work with and more relevant to an agent's needs. We provide some intuition to motivate the need for such reduced information spaces, called workspaces, give a formal definition, and suggest possible methods of deriving them.

Impact of ammonium nitrate and sodium nitrate on tadpoles of Alytes obstetricans.

PubMed

Garriga, Núria; Montori, A; Llorente, G A

2017-07-01

The presence of pesticides, herbicides and fertilisers negatively affect aquatic communities in general, and particularly amphibians in their larval phase, even though sensitivity to pollutants is highly variable among species. The Llobregat Delta (Barcelona, Spain) has experienced a decline of amphibian populations, possibly related to the reduction in water quality due to the high levels of farming activity, but also to habitat loss and alteration. We studied the effects of increasing ammonium nitrate and sodium nitrate levels on the survival and growth rate of Alytes obstetricans tadpoles under experimental conditions. We exposed larvae to increasing concentrations of nitrate and ammonium for 14 days and then exposed them to water without pollutants for a further 14 days. Only the higher concentrations of ammonium (>33.75 mg/L) caused larval mortality. The growth rate of larvae was reduced at ≥22.5 mg/L NH 4 + , although individuals recovered and even increased their growth rate once exposure to the pollutant ended. The effect of nitrate on growth rate was detected at ≥80 mg/L concentrations, and the growth rate reduction in tadpoles was even observed during the post-exposure phase. The concentrations of ammonium with adverse effects on larvae are within the range levels found in the study area, while the nitrate concentrations with some adverse effect are close to the upper range limit of current concentrations in the study area. Therefore, only the presence of ammonium in the study area is likely to be considered of concern for the population of this species, even though the presence of nitrate could cause some sublethal effects. These negative effects could have an impact on population dynamics, which in this species is highly sensitive to larval mortality due to its small clutch size and prolonged larval period compared to other anuran amphibians.

Tissue radionuclide concentrations in water birds and upland birds on the Hanford Site (USA) from 1971-2009.

PubMed

Delistraty, Damon; Van Verst, Scott

2011-08-01

Historical operations at the Hanford Site (Washington State, USA) have released a wide array of non-radionuclide and radionuclide contaminants into the environment. As a result, there is a need to characterize contaminant effects on site biota. Within this framework, the main purpose of our study was to evaluate radionuclide concentrations in bird tissue, obtained from the Hanford Environmental Information System (HEIS). The database was sorted by avian group (water bird vs. upland bird), radionuclide (over 20 analytes), tissue (muscle, bone, liver), location (onsite vs. offsite), and time period (1971-1990 vs. 1991-2009). Onsite median concentrations in water birds were significantly higher (Bonferroni P < 0.05) than those in onsite upland birds for Cs-137 in muscle (1971-1990) and Sr-90 in bone (1991-2009), perhaps due to behavioral, habitat, or trophic species differences. Onsite median concentrations in water birds were higher (borderline significance with Bonferroni P = 0.05) than those in offsite birds for Cs-137 in muscle (1971-1990). Onsite median concentrations in the earlier time period were significantly higher (Bonferroni P < 0.05) than those in the later time period for Co-60, Cs-137, Eu-152, and Sr-90 in water bird muscle and for Cs-137 in upland bird muscle tissue. Median concentrations of Sr-90 in bone were significantly higher (Bonferroni P < 0.05) than those in muscle for both avian groups and both locations. Over the time period, 1971-2009, onsite median internal dose was estimated for each radionuclide in water bird and upland bird tissues. However, a meaningful dose comparison between bird groups was not possible, due to a dissimilar radionuclide inventory, mismatch of time periods for input radionuclides, and lack of an external dose estimate. Despite these limitations, our results contribute toward ongoing efforts to characterize ecological risk at the Hanford Site. Copyright © 2011 Elsevier Ltd. All rights reserved.

Reproductive impacts and physiological adaptations of zebrafish to elevated dietary nickel.

PubMed

Alsop, Derek; Lall, Santosh P; Wood, Chris M

2014-09-01

Nickel (Ni) concentrations in the environment can rise due to human industrial activities. The toxicity of waterborne Ni to aquatic animals has been examined in a number of previous studies; however, little is known about the impacts of elevated dietary Ni. In the present study, zebrafish were chronically fed diets containing two concentrations of Ni [3.7 (control) and 116 μg Ni/g diet]. Ni-exposed males, but not females, were significantly smaller (26%) compared to controls at 80 days. In addition, total egg production was decreased by 65% in the Ni treatment at 75-78 days of the experiment. Ni was ubiquitously distributed in control animals (similar to previous studies), and concentrations varied between tissues by 15-fold. Ni exposure resulted in modest but significant Ni accumulation in some tissues (increases were highest in brain, vertebrae and gut; 44%, 34% and 25%, respectively), an effect observed only at 80 days. The limited Ni accumulation may be due to (1) the lack of an acidified stomach in zebrafish and/or (2) the efficient upregulation of Ni transport and excretion mechanisms, as indicated by the 4.5-fold increase in waterborne (63)Ni uptake by Ni-exposed fish. Eggs from Ni-exposed adults had Ni concentrations that were 5.2-fold higher than controls. However, by 4 days post fertilization, larvae had similar Ni concentrations as controls, demonstrating a capacity for rapid Ni depuration. Larvae from Ni-exposed adults were also more resistant to waterborne Ni (35% increase in the 96-h LC50 over controls). In conclusion, elevated dietary Ni significantly affected zebrafish reproduction despite only modest tissue Ni accumulation. There were also indications of adaptation, including increased Ni uptake rates and increased Ni tolerance of offspring from Ni-exposed adults. Ni concentrations were particularly elevated in the brain with exposure; possible relations to growth and reproductive impacts require further study. Copyright © 2014 Elsevier Inc. All rights reserved.

Diffusive-like effects and possible non trivial local topology on the half-Heusler YPdBi compound

NASA Astrophysics Data System (ADS)

Souza, J. C.; Lesseux, G. G.; Urbano, R. R.; Rettori, C.; Pagliuso, P. G.

2018-05-01

The non-ambiguous experimental identification of topological states of matter is one of the main interesting problems regarding this new quantum state of matter. In particular, the half-Heusler family RMT (R = rare-earth, T = Pd, Pt or Au and T = Bi, Sb, Pb or Sn) could be a useful platform to explore these states due to their cubic symmetry and the topological properties tunable via their unit cell volume and/or the nuclear charges of the M and T atoms. In this work, we report electron spin resonance (ESR) and complementary macroscopic measurements in the Nd3 + -doped putative topologically trivial semimetal YPdBi. Following the Nd3 + ESR lineshape as a function of microwave power, size of the particle and temperature, we have been able to observe an evolution from a Dysonian lineshape to a diffusive-like lineshape. Furthermore, the Nd3 + ESR intensity saturation is concentration dependent, which could be due to a phonon-bottleneck process. Comparing these results with the Nd3 + -doped YPtBi, we discuss a possible scenario in which the Nd3 + ions could locally tune the topological properties of the system.

Diffusion sampler testing at Naval Air Station North Island, San Diego County, California, November 1999 to January 2000

USGS Publications Warehouse

Vroblesky, Don A.; Peters, Brian C.

2000-01-01

Volatile organic compound concentrations in water from diffusion samplers were compared to concentrations in water obtained by low-flow purging at 15 observation wells at the Naval Air Station North Island, San Diego, California. Multiple diffusion samplers were installed in the wells. In general, comparisons using bladder pumps and diffusion samplers showed similar volatile organic carbon concentrations. In some wells, sharp concentration gradients were observed, such as an increase in cis-1,2-dichloroethene concentration from 100 to 2,600 micrograms per liter over a vertical distance of only 3.4 feet. In areas where such sharp gradients were observed, concentrations in water obtained by low-flow sampling at times reflected an average concentration over the area of influence; however, concentrations obtained by using the diffusion sampler seemed to represent the immediate vicinity of the sampler. When peristaltic pumps were used to collect ground-water samples by low-flow purging, the volatile organic compound concentrations commonly were lower than concentrations obtained by using diffusion samplers. This difference may be due to loss of volatiles by degassing under negative pressures in the sampling lines induced while using the peristaltic pump, mixing in the well screen, or possible short-circuiting of water from an adjacent depth. Diffusion samplers placed in buckets of freephase jet fuel (JP-5) and Stoddard solvent from observation wells did not show evidence of structural integrity loss during the 2 months of equilibration, and volatile organic compounds detected in the free-phase fuel also were detected in the water from the diffusion samplers.

A novel way to monitor urine concentration: fluorescent concentration matrices.

PubMed

Dubayova, Katarina; Luckova, Iveta; Sabo, Jan; Karabinos, Anton

2015-01-01

The amount of water found in urine is important diagnostic information; nevertheless it is not yet directly determined. Indirectly, the water content in urine is expressed by its density (specific gravity). However, without the diuresis value it is not possible to determine whether the increase in density of urine is due to a decrease in water secretion or an increase in the concentration of secreted substances. This problem can be solved by the use of fluorescent concentration 3D-matrices which characterise urine concentration through the pφ (or -logφ) value of the first fluorescence centre. The urine fluorescent concentration 3D-matrix was created by the alignment of the synchronous spectra of the dilution series of urine starting from undiluted (pφ = 0) to 1000-fold diluted urine (pφ = 3). Using the fluorescence concentration 3D-matrix analysis of the urine samples from healthy individuals, a reference range was established for the value pφ, determining the normal, concentrated or diluted type of urine. The diagnostic potential of this approach was tested on urine samples from two patients with a chronic glomerulonephritis. The pφ value of the urine fluorescence concentration 3D-matrix analysis determines whether the urine sample falls within the normal, concentrated or diluted type of urine. This parameter can be directly utilised in sportsmen's hydration state monitoring, as well as in the diagnosis and treatment of serious diseases. An important advantage of this novel diagnostic approach is that a 12/24 h urine collection is not required, which predetermines it for use especially within paediatrics.

Regional long-term model of radioactivity dispersion and fate in the Northwestern Pacific and adjacent seas: application to the Fukushima Dai-ichi accident.

PubMed

Maderich, V; Bezhenar, R; Heling, R; de With, G; Jung, K T; Myoung, J G; Cho, Y-K; Qiao, F; Robertson, L

2014-05-01

The compartment model POSEIDON-R was modified and applied to the Northwestern Pacific and adjacent seas to simulate the transport and fate of radioactivity in the period 1945-2010, and to perform a radiological assessment on the releases of radioactivity due to the Fukushima Dai-ichi accident for the period 2011-2040. The model predicts the dispersion of radioactivity in the water column and in sediments, the transfer of radionuclides throughout the marine food web, and subsequent doses to humans due to the consumption of marine products. A generic predictive dynamic food-chain model is used instead of the biological concentration factor (BCF) approach. The radionuclide uptake model for fish has as a central feature the accumulation of radionuclides in the target tissue. The three layer structure of the water column makes it possible to describe the vertical structure of radioactivity in deep waters. In total 175 compartments cover the Northwestern Pacific, the East China and Yellow Seas and the East/Japan Sea. The model was validated from (137)Cs data for the period 1945-2010. Calculated concentrations of (137)Cs in water, bottom sediments and marine organisms in the coastal compartment, before and after the accident, are in close agreement with measurements from the Japanese agencies. The agreement for water is achieved when an additional continuous flux of 3.6 TBq y(-1) is used for underground leakage of contaminated water from the Fukushima Dai-ichi NPP, during the three years following the accident. The dynamic food web model predicts that due to the delay of the transfer throughout the food web, the concentration of (137)Cs for piscivorous fishes returns to background level only in 2016. For the year 2011, the calculated individual dose rate for Fukushima Prefecture due to consumption of fishery products is 3.6 μSv y(-1). Following the Fukushima Dai-ichi accident the collective dose due to ingestion of marine products for Japan increased in 2011 by a factor of 6 in comparison with 2010. Copyright © 2013 Elsevier Ltd. All rights reserved.

Osmolyte cooperation affects turgor dynamics in plants

NASA Astrophysics Data System (ADS)

Argiolas, Alfredo; Puleo, Gian Luigi; Sinibaldi, Edoardo; Mazzolai, Barbara

2016-07-01

Scientists have identified turgor-based actuation as a fundamental mechanism in plant movements. Plant cell turgor is generated by water influx due to the osmolyte concentration gradient through the cell wall and the plasma membrane behaving as an osmotic barrier. Previous studies have focused on turgor modulation with respect to potassium chloride (KCl) concentration changes, although KCl is not efficiently retained in the cell, and many other compounds, including L-glutamine (L-Gln) and D-glucose (D-Glc), are present in the cytosol. In fact, the contributions of other osmolytes to turgor dynamics remain to be elucidated. Here, we show the association of osmolytes and their consequent cooperative effects on the time-dependent turgor profile generated in a model cytosol consisting of KCl, D-Glc and L-Gln at experimentally measured plant motor/generic cell concentrations and at modified concentrations. We demonstrate the influence and association of the osmolytes using osmometry and NMR measurements. We also show, using a plant cell-inspired device we previously developed, that osmolyte complexes, rather than single osmolytes, permit to obtain higher turgor required by plant movements. We provide quantitative cues for deeper investigations of osmolyte transport for plant movement, and reveal the possibility of developing osmotic actuators exploiting a dynamically varying concentration of osmolytes.

Osmolyte cooperation affects turgor dynamics in plants.

PubMed

Argiolas, Alfredo; Puleo, Gian Luigi; Sinibaldi, Edoardo; Mazzolai, Barbara

2016-07-22

Scientists have identified turgor-based actuation as a fundamental mechanism in plant movements. Plant cell turgor is generated by water influx due to the osmolyte concentration gradient through the cell wall and the plasma membrane behaving as an osmotic barrier. Previous studies have focused on turgor modulation with respect to potassium chloride (KCl) concentration changes, although KCl is not efficiently retained in the cell, and many other compounds, including L-glutamine (L-Gln) and D-glucose (D-Glc), are present in the cytosol. In fact, the contributions of other osmolytes to turgor dynamics remain to be elucidated. Here, we show the association of osmolytes and their consequent cooperative effects on the time-dependent turgor profile generated in a model cytosol consisting of KCl, D-Glc and L-Gln at experimentally measured plant motor/generic cell concentrations and at modified concentrations. We demonstrate the influence and association of the osmolytes using osmometry and NMR measurements. We also show, using a plant cell-inspired device we previously developed, that osmolyte complexes, rather than single osmolytes, permit to obtain higher turgor required by plant movements. We provide quantitative cues for deeper investigations of osmolyte transport for plant movement, and reveal the possibility of developing osmotic actuators exploiting a dynamically varying concentration of osmolytes.

Selection of associated heterotrophs by methane-oxidizing bacteria at different copper concentrations.

PubMed

van der Ha, David; Vanwonterghem, Inka; Hoefman, Sven; De Vos, Paul; Boon, Nico

2013-03-01

Due to the increasing atmospheric concentration of the greenhouse gas methane, more knowledge is needed on the management of methanotrophic communities. While most studies have focused on the characteristics of the methane-oxidizing bacteria (MOB), less is known about their interactions with the associated heterotrophs. Interpretative tools based on denaturing gradient gel electrophoresis allowed to evaluate the influence of copper-an important enzymatic regulator for MOB-on the activity and composition of the bacterial community. Over 30 days, enrichments with 0.1, 1.0 and 10 μM Cu(2+) respectively, showed comparable methane oxidation activities. The different copper concentrations did not create major shifts in the methanotrophic communities, as a Methylomonas sp. was able to establish dominance at all different copper concentrations by switching between both known methane monooxygenases. The associated heterotrophic communities showed continuous shifts, but over time all cultures evolved to a comparable composition, independent of the copper concentration. This indicates that the MOB selected for certain heterotrophs, possibly fulfilling vital processes such as removal of toxic compounds. The presence of a large heterotrophic food web indirectly depending on methane as sole carbon and energy source was confirmed by a clone library wherein MOB only formed a minority of the identified species.

Osmolyte cooperation affects turgor dynamics in plants

PubMed Central

Argiolas, Alfredo; Puleo, Gian Luigi; Sinibaldi, Edoardo; Mazzolai, Barbara

2016-01-01

Scientists have identified turgor-based actuation as a fundamental mechanism in plant movements. Plant cell turgor is generated by water influx due to the osmolyte concentration gradient through the cell wall and the plasma membrane behaving as an osmotic barrier. Previous studies have focused on turgor modulation with respect to potassium chloride (KCl) concentration changes, although KCl is not efficiently retained in the cell, and many other compounds, including L-glutamine (L-Gln) and D-glucose (D-Glc), are present in the cytosol. In fact, the contributions of other osmolytes to turgor dynamics remain to be elucidated. Here, we show the association of osmolytes and their consequent cooperative effects on the time-dependent turgor profile generated in a model cytosol consisting of KCl, D-Glc and L-Gln at experimentally measured plant motor/generic cell concentrations and at modified concentrations. We demonstrate the influence and association of the osmolytes using osmometry and NMR measurements. We also show, using a plant cell-inspired device we previously developed, that osmolyte complexes, rather than single osmolytes, permit to obtain higher turgor required by plant movements. We provide quantitative cues for deeper investigations of osmolyte transport for plant movement, and reveal the possibility of developing osmotic actuators exploiting a dynamically varying concentration of osmolytes. PMID:27445173

Perfluoroalkyl substances in human bone: concentrations in bones and effects on bone cell differentiation.

PubMed

Koskela, A; Koponen, J; Lehenkari, P; Viluksela, M; Korkalainen, M; Tuukkanen, J

2017-07-28

Perfluoroalkyl substances (PFAS), including two most commonly studied compounds perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are widely distributed environmental pollutants, used extensively earlier. Due to their toxicological effects the use of PFAS is now regulated. Based on earlier studies on PFOA's distribution in bone and bone marrow in mice, we investigated PFAS levels and their possible link to bone microarchitecture of human femoral bone samples (n = 18). Soft tissue and bone biopsies were also taken from a 49-year old female cadaver for PFAS analyses. We also studied how PFOA exposure affects differentiation of human osteoblasts and osteoclasts. PFAS were detectable from all dry bone and bone marrow samples, PFOS and PFOA being the most prominent. In cadaver biopsies, lungs and liver contained the highest concentrations of PFAS, whereas PFAS were absent in bone marrow. Perfluorononanoic acid (PFNA) was present in the bones, PFOA and PFOS were absent. In vitro results showed no disturbance in osteogenic differentiation after PFOA exposure, but in osteoclasts, lower concentrations led to increased resorption, which eventually dropped to zero after increase in PFOA concentration. In conclusion, PFAS are present in bone and have the potential to affect human bone cells partly at environmentally relevant concentrations.

Heavy Metal Content in Chilean Fish Related to Habitat Use, Tissue Type and River of Origin.

PubMed

Copaja, S V; Pérez, C A; Vega-Retter, C; Véliz, D

2017-12-01

In this study, we analyze the concentration of ten metals in two freshwater fish-the benthic catfish Trichomycterus areolatus and the limnetic silverside Basilichthys microlepidotus-in order to detect possible accumulation differences related to fish habitat (benthic or pelagic), tissue type (gill, liver and muscle), and the river of origin (four different rivers) in central Chile. The MANOVA performed with all variables and metals, revealed independent effects of fish, tissue and river. In the case of the fish factor, Cu, Cr, Mo and Zn showed statistically higher concentrations in catfish compared with silverside for all tissues and in all rivers (p < 0.05). In the case of the tissue factor, Al, Cr, Fe and Mn had statistically higher concentrations in liver and gills than in muscle (p  < 0.05). For the river effect, the analysis showed higher concentrations of Cr, Mn and Pb in the Cogoti river and the lower concentrations in the Recoleta river. These results suggest that not all metals have the same pattern of accumulation; however, some metals tend to accumulate more in readily catfish, probably due to their benthic habit, and in liver and gill tissue, probably as a result of accumulation from food sources and respiration.

Influence of sodium dodecyl sulfate on swelling, erosion and release behavior of HPMC matrix tablets containing a poorly water-soluble drug.

PubMed

Zeng, Aiguo; Yuan, Bingxiang; Fu, Qiang; Wang, Changhe; Zhao, Guilan

2009-01-01

The effect of sodium dodecyl sulfate (SDS) on the swelling, erosion and release behavior of HPMC matrix tablets was examined. Swelling and erosion of HPMC matrix tablets were determined by measuring the wet and subsequent dry weights of matrices. The rate of uptake of the dissolution medium by the matrix was quantified using a square root relationship whilst the erosion of the polymer was described using the cube root law. The extent of swelling decreased with increasing SDS concentrations in the dissolution medium but the rate of erosion was found to follow a reverse trend. Such phenomena might have been caused by the attractive hydrophobic interaction between HPMC and SDS as demonstrated by the cloud points of the solutions containing both the surfactant and polymer. Release profiles of nimodipine from HPMC tablets in aqueous media containing different concentrations of SDS were finally studied. Increasing SDS concentrations in the medium was shown to accelerate the release of nimodipine from the tablets, possibly due to increasing nimodipine solubility and increasing rate of erosion by increasing SDS concentrations in the dissolution medium.

Zytoprotektion mit Amifostin (Ethyol®) in der Chemotherapie: Meta-Analyse zum pharmakokinetischen Interaktionspotential mit Zytostatika.

PubMed

Czejka, Martin; Schüller, Johannes; Kletzl, Heidemarie

2017-08-25

The cytoprotective agent amifostine (AMI) is capable to protect healthy cells (contrary to tumor cells) due to higher activity of alkaline phosphatase at the membrane site of normal cells. In seven clinical trials the influence of AMI on the pharmacokinetics of different cytostatics was investigated. Preadministration of AMI increased Cmax of doxorubicin (+ 44 %, p < 0.06), epirubicin (+ 31 %, P < 0.08), mitomycin C (+ 41 %, p < 0.01) and docetaxel (+ 31 % and + 17 %, not significant). In contrary, the peak concentration of pirarubicin , the tetrahydropyranyl-prodrug of doxorubicin was decreased (- 50 %, P < 0.03), leading to an equal higher concentrationof doxorubicin in the blood . In accordance to the peak concentrations, the AUC'ast was increased by chemoprotection: doxorubicin + 53 % (p < 0.01) and epirubicin + 23 % (not significant), docetaxel + 25 % and + 31 % (not significant). AUC'ast of mitomycin C and paclitaxel seemed to be unaffected by preadministered AMI. A particular inhibition of the protein binding by AMI has been identified as one reason for higher serum concentrations of anthracycline drugs. After cytoprotection, a possible increase of the cytostatic's Serum concentrations should be taken into account for optimal dosage schedules.

Compact high-sensitivity potentiometer for detection of low ion concentrations in liquids

NASA Astrophysics Data System (ADS)

Balevicius, Z.; Lescinskas, R.; Celiesiute, R.; Stirke, A.; Balevicius, S.; Kersulis, S.; Bleizgys, V.; Maciuleviciene, R.; Ramanavicius, A.; Zurauskiene, N.

2018-04-01

The compact potentiometer, based on an electronic circuit protected from electrostatic and electromagnetic interference, was developed for the measurement of low ion concentrations in liquids. The electronic circuit of the potentiometer, consisting of analogous and digital parts, enables the measurement of fA currents. This makes it possible to perform reliable measurements of ion concentrations in liquids that are as small as 10-8-10-7M. The instrument was tested using electrodes that were selective for tetraphenylphosphonium (TPP+) ions. It was demonstrated that the characteristic response time of the potentiometer electronic circuit to changes in the concentration of these ions in a liquid was in the order of 10 s. An investigation of TPP+ absorption by baker yeast has shown that this device can be successfully used for long term (several hours) measurements with zero signal drift, which was about 1 μV/s. Finally, due to the small dimensions of the electronic circuit (7.5 × 2 × 1.5 cm), this potentiometer can be easily installed at a large apparatus in the laboratory condition (≈25 °C), such as high pulsed electrical generators of magnetic fields that are used in electroporation studies of biological cells.

Modelling and Optimization of Polycaprolactone Ultrafine-Fibres Electrospinning Process Using Response Surface Methodology

PubMed Central

Ruys, Andrew J.

2018-01-01

Electrospun fibres have gained broad interest in biomedical applications, including tissue engineering scaffolds, due to their potential in mimicking extracellular matrix and producing structures favourable for cell and tissue growth. The development of scaffolds often involves multivariate production parameters and multiple output characteristics to define product quality. In this study on electrospinning of polycaprolactone (PCL), response surface methodology (RSM) was applied to investigate the determining parameters and find optimal settings to achieve the desired properties of fibrous scaffold for acetabular labrum implant. The results showed that solution concentration influenced fibre diameter, while elastic modulus was determined by solution concentration, flow rate, temperature, collector rotation speed, and interaction between concentration and temperature. Relationships between these variables and outputs were modelled, followed by an optimization procedure. Using the optimized setting (solution concentration of 10% w/v, flow rate of 4.5 mL/h, temperature of 45 °C, and collector rotation speed of 1500 RPM), a target elastic modulus of 25 MPa could be achieved at a minimum possible fibre diameter (1.39 ± 0.20 µm). This work demonstrated that multivariate factors of production parameters and multiple responses can be investigated, modelled, and optimized using RSM. PMID:29562614

Measurement of plasma unbound unconjugated bilirubin.

PubMed

Ahlfors, C E

2000-03-15

A method is described for measuring the unconjugated fraction of the unbound bilirubin concentration in plasma by combining the peroxidase method for determining unbound bilirubin with a diazo method for measuring conjugated and unconjugated bilirubin. The accuracy of the unbound bilirubin determination is improved by decreasing sample dilution, eliminating interference by conjugated bilirubin, monitoring changes in bilirubin concentration using diazo derivatives, and correcting for rate-limiting dissociation of bilirubin from albumin. The unbound unconjugated bilirubin concentration by the combined method in plasma from 20 jaundiced newborns was significantly greater than and poorly correlated with the unbound bilirubin determined by the existing peroxidase method (r = 0.7), possibly due to differences in sample dilution between the methods. The unbound unconjugated bilirubin was an unpredictable fraction of the unbound bilirubin in plasma samples from patients with similar total bilirubin concentrations but varying levels of conjugated bilirubin. A bilirubin-binding competitor was readily detected at a sample dilution typically used for the combined test but not at the dilution used for the existing peroxidase method. The combined method is ideally suited to measuring unbound unconjugated bilirubin in jaundiced human newborns or animal models of kernicterus. Copyright 2000 Academic Press.

High-spatial-resolution nanoparticle x-ray fluorescence tomography

NASA Astrophysics Data System (ADS)

Larsson, Jakob C.; Vâgberg, William; Vogt, Carmen; Lundström, Ulf; Larsson, Daniel H.; Hertz, Hans M.

2016-03-01

X-ray fluorescence tomography (XFCT) has potential for high-resolution 3D molecular x-ray bio-imaging. In this technique the fluorescence signal from targeted nanoparticles (NPs) is measured, providing information about the spatial distribution and concentration of the NPs inside the object. However, present laboratory XFCT systems typically have limited spatial resolution (>1 mm) and suffer from long scan times and high radiation dose even at high NP concentrations, mainly due to low efficiency and poor signal-to-noise ratio. We have developed a laboratory XFCT system with high spatial resolution (sub-100 μm), low NP concentration and vastly decreased scan times and dose, opening up the possibilities for in-vivo small-animal imaging research. The system consists of a high-brightness liquid-metal-jet microfocus x-ray source, x-ray focusing optics and an energy-resolving photon-counting detector. By using the source's characteristic 24 keV line-emission together with carefully matched molybdenum nanoparticles the Compton background is greatly reduced, increasing the SNR. Each measurement provides information about the spatial distribution and concentration of the Mo nanoparticles. A filtered back-projection method is used to produce the final XFCT image.

Numerical study of underwater dispersion of dilute and dense sediment-water mixtures

NASA Astrophysics Data System (ADS)

Chan, Ziying; Dao, Ho-Minh; Tan, Danielle S.

2018-05-01

As part of the nodule-harvesting process, sediment tailings are released underwater. Due to the long period of clouding in the water during the settling process, this presents a significant environmental and ecological concern. One possible solution is to release a mixture of sediment tailings and seawater, with the aim of reducing the settling duration as well as the amount of spreading. In this paper, we present some results of numerical simulations using the smoothed particle hydrodynamics (SPH) method to model the release of a fixed volume of pre-mixed sediment-water mixture into a larger body of quiescent water. Both the sediment-water mixture and the “clean” water are modeled as two different fluids, with concentration-dependent bulk properties of the sediment-water mixture adjusted according to the initial solids concentration. This numerical model was validated in a previous study, which indicated significant differences in the dispersion and settling process between dilute and dense mixtures, and that a dense mixture may be preferable. For this study, we investigate a wider range of volumetric concentration with the aim of determining the optimum volumetric concentration, as well as its overall effectiveness compared to the original process (100% sediment).

Dynamics of Model Hydraulic Fracturing Liquid Studied by Two-Dimensional Infrared Spectroscopy

NASA Astrophysics Data System (ADS)

Daley, Kim; Kubarych, Kevin J.

2014-06-01

The technique of two-dimensional infrared (2DIR) spectroscopy is used to expose the chemical dynamics of various concentrations of polymers and their monomers in heterogeneous mixtures. An environmentally relevant heterogeneous mixture, which inspires this study, is hydraulic fracturing liquid (HFL). Hydraulic fracking is a technique used to extract natural gas from shale deposits. HFL consists of mostly water, proppant (sand), an emulsifier (guar), and other chemicals specific to the drilling site. Utilizing a metal carbonyl as a probe, we observe the spectral dynamics of the polymer, guar, and its monomer, mannose, and compare the results to see how hydration dynamics change with varying concentration. Another polymer, Ficoll, and its monomer, sucrose, are also compared to see how polymer size affects hydration dynamics. The two results are as follows: (1) Guar experiences collective hydration at high concentrations, where as mannose experiences independent hydration; (2) no collective hydration is observed for Ficoll in the same concentration range as guar, possibly due to polymer shape and size. HFL experiences extremely high pressure during natural gas removal, so future studies will focus on how increased pressure affects the hydration dynamics of polymers and monomers.

Genetic control of soybean seed oil: II. QTL and genes that increase oil concentration without decreasing protein or with increased seed yield.

PubMed

Eskandari, Mehrzad; Cober, Elroy R; Rajcan, Istvan

2013-06-01

Soybean [Glycine max (L.) Merrill] seed oil is the primary global source of edible oil and a major renewable and sustainable feedstock for biodiesel production. Therefore, increasing the relative oil concentration in soybean is desirable; however, that goal is complex due to the quantitative nature of the oil concentration trait and possible effects on major agronomic traits such as seed yield or protein concentration. The objectives of the present study were to study the relationship between seed oil concentration and important agronomic and seed quality traits, including seed yield, 100-seed weight, protein concentration, plant height, and days to maturity, and to identify oil quantitative trait loci (QTL) that are co-localized with the traits evaluated. A population of 203 F4:6 recombinant inbred lines, derived from a cross between moderately high oil soybean genotypes OAC Wallace and OAC Glencoe, was developed and grown across multiple environments in Ontario, Canada, in 2009 and 2010. Among the 11 QTL associated with seed oil concentration in the population, which were detected using either single-factor ANOVA or multiple QTL mapping methods, the number of QTL that were co-localized with other important traits QTL were six for protein concentration, four for seed yield, two for 100-seed weight, one for days to maturity, and one for plant height. The oil-beneficial allele of the QTL tagged by marker Sat_020 was positively associated with seed protein concentration. The oil favorable alleles of markers Satt001 and GmDGAT2B were positively correlated with seed yield. In addition, significant two-way epistatic interactions, where one of the interacting markers was solely associated with seed oil concentration, were identified for the selected traits in this study. The number of significant epistatic interactions was seven for yield, four for days to maturity, two for 100-seed weight, one for protein concentration, and one for plant height. The identified molecular markers associated with oil-related QTL in this study, which also have positive effects on other important traits such as seed yield and protein concentration, could be used in the soybean marker breeding programs aimed at developing either higher seed yield and oil concentration or higher seed protein and oil concentration per hectare. Alternatively, selecting complementary parents with greater breeding values due to positive epistatic interactions could lead to the development of higher oil soybean cultivars.

Particulate air pollution from bushfires: human exposure and possible health effects.

PubMed

Karthikeyan, Sathrugnan; Balasubramanian, Rajasekhar; Iouri, Kostetski

2006-11-01

Toxicological studies have implicated trace metals adsorbed onto airborne particles as possible contributors to respiratory and/or cardiovascular inflammation. In particular, the water-soluble metal content is considered to be a harmful component of airborne particulate matter. In this work, the trace metal characteristics of airborne particulate matter, PM2.5, collected in Singapore from February to March 2005 were investigated with specific reference to their bioavailability. PM2.5 mass concentrations varied between 20.9 mug/m3 and 46.3 microg/m3 with an average mass of 32.8 microg/m3. During the sampling period, there were several bushfires in Singapore that contributed to sporadic increases in the particulate air pollution, accompanied by an acrid smell and asthma-related allergies. The aerosol samples were subjected to analysis of trace elements for determining their total concentrations as well as their water soluble fractions. Our results showed an increase in concentration of several water-soluble trace metals during bushfires compared to their urban background levels in Singapore. In order to measure the human exposure to particulate air pollution, the daily respiratory uptake (DRU) of several trace metals was calculated and compared between haze and nonhaze periods. The DRU values were significantly higher for several metals, including Zn, Cu, and Fe, during bushfires. Electron paramagnetic resonance (EPR) measurements showed that the particulate samples collected during bush fires generate more toxic hydroxyl radicals (OH.) than those in the background air, due to the presence of more soluble iron ions.

A Re-evaluation of the Ferrozine Method for Dissolved Iron: The Effect of Organic Interferences

NASA Astrophysics Data System (ADS)

Balind, K.; Barber, A.; Gelinas, Y.

2016-12-01

Among the most commonly used analytical methods in geochemistry is the ferrozine method for determining dissolved iron concentration in water (1). This cheap and easy-to-use spectrophotometric method involves a complexing agent (ferrozine), a reducing agent (hydroxylamine-HCl) and buffer (ammonium acetate with ammonium hydroxide). Previous studies have demonstrated that complex organic matter (OM) originating from the Suwannee River did not lead to a significantly underestimation of the measured iron content in OM amended iron solutions (2). The authors concluded that this method could be used even in organic rich (i.e., 25 mg/L) waters. Here we compare the concentration of Fe measured using this spectrophotometric method to the total Fe as measured by ICP-MS in the presence/absence of specific organic molecules to ascertain if they interfere with the ferrozine method. We show that certain molecules with hydroxyl and carboxyl functional groups as well as multi-dentate chelating species have a significant effect on the measured iron concentrations. Two possible mechanisms likely are responsible for the inefficiency of this method in the presence of specific organic molecules; 1) incomplete reduction of Fe(III) bound to organic molecules, or 2) competition between the OM and ferrozine for the available iron. We address these possibilities separately by varying the experimental conditions. These methodological artifacts may have far reaching implications due to the extensive use of this method. Stookey, L. L., Anal. Chem., 42, 779 (1970). Viollier, E., et al., Applied Geochem., 15, 785 (2000).

On the Use of Fourier Transform Infrared (FT-IR) Spectroscopy and Synthetic Calibration Spectra to Quantify Gas Concentrations in a Fischer-Tropsch Catalyst System

NASA Technical Reports Server (NTRS)

Ferguson, Frank T.; Johnson, Natasha M.; Nuth, Joseph A., III

2015-01-01

One possible origin of prebiotic organic material is that these compounds were formed via Fischer-Tropsch-type (FTT) reactions of carbon monoxide and hydrogen on silicate and oxide grains in the warm, inner-solar nebula. To investigate this possibility, an experimental system has been built in which the catalytic efficiency of different grain-analog materials can be tested. During such runs, the gas phase above these grain analogs is sampled using Fourier transform infrared (FT-IR) spectroscopy. To provide quantitative estimates of the concentration of these gases, a technique in which high-resolution spectra of the gases are calculated using the high-resolution transmission molecular absorption (HITRAN) database is used. Next, these spectra are processed via a method that mimics the processes giving rise to the instrumental line shape of the FT-IR spectrometer, including apodization, self-apodization, and broadening due to the finite resolution. The result is a very close match between the measured and computed spectra. This technique was tested using four major gases found in the FTT reactions: carbon monoxide, methane, carbon dioxide, and water. For the ranges typical of the FTT reactions, the carbon monoxide results were found to be accurate to within 5% and the remaining gases accurate to within 10%. These spectra can then be used to generate synthetic calibration data, allowing the rapid computation of the gas concentrations in the FTT experiments.

Estimation of indoor and outdoor ratios of selected volatile organic compounds in Canada

NASA Astrophysics Data System (ADS)

Xu, Jing; Szyszkowicz, Mieczyslaw; Jovic, Branka; Cakmak, Sabit; Austin, Claire C.; Zhu, Jiping

2016-09-01

Indoor air and outdoor air concentration (I/O) ratio can be used to identify the origins of volatile organic compounds (VOCs). I/O ratios of 25 VOCs in Canada were estimated based on the data collected in various areas in Canada between September 2009 and December 2011. The indoor VOC data were extracted from the Canadian Health Measures Survey (CHMS). Outdoor VOC data were obtained from Canada's National Air Pollution Surveillance (NAPS) Network. The sampling locations covered nine areas in six provinces in Canada. Indoor air concentrations were found higher than outdoor air for all studied VOCs, except for carbon tetrachloride. Two different approaches were employed to estimate the I/O ratios; both approaches produced similar I/O values. The I/O ratios obtained from this study were similar to two other Canadian studies where indoor air and outdoor air of individual dwellings were measured. However, the I/O ratios found in Canada were higher than those in European cities and in two large USA cities, possibly due to the fact that the outdoor air concentrations recorded in the Canadian studies were lower. Possible source origins identified for the studied VOCs based on their I/O ratios were similar to those reported by others. In general, chlorinated hydrocarbons, short-chain (C5, C6) n-alkanes and benzene had significant outdoor sources, while long-chain (C10sbnd C12) n-alkanes, terpenes, naphthalene and styrene had significant indoor sources. The remaining VOCs had mixed indoor and outdoor sources.

Direct measurement of glutamate release in the brain using a dual enzyme-based electrochemical sensor.

PubMed

Hu, Y; Mitchell, K M; Albahadily, F N; Michaelis, E K; Wilson, G S

1994-10-03

The in vivo measurement of the rapid changes in the extracellular concentrations of L-glutamic acid in the mammalian brain during normal neuronal activity or following excessive release due to episodes of anoxia or ischemia has not been possible to this date. Current techniques for the measurement of the release of endogenous glutamate into the extracellular space of the central nervous system are relatively slow and do not measure the actual concentration of free glutamate in the extracellular space. An enzyme-based electrode with rapid response times (about 1 s) and high degree of sensitivity (less than 2 microM) and selectivity for L-glutamic acid is described in this paper. This electrode has both L-glutamate and ascorbate oxidase immobilized on its surface. The latter enzyme removes almost completely any interferences produced by the high levels of extracellular ascorbate present in brain tissue. The response of the electrode to glutamate and other potentially interfering substances was fully characterized in vitro and its selectivity, sensitivity and rapidity in responding to a rise in extracellular glutamate concentrations was also demonstrated in vivo. Placement of the electrode in the dentate gyrus of the hippocampus led to the detection of both KCl-induced release of L-glutamic acid and the release induced by stimulation of the axons in the perforant pathway. The development of this selective, sensitive and rapidly responding glutamate sensor should make it now possible to measure the dynamic events associated with glutamate neurotransmission in the central nervous system.

On the Use of Fourier Transform Infrared (FT-IR) Spectroscopy and Synthetic Calibration Spectra to Quantify Gas Concentrations in a Fischer-Tropsch Catalyst System.

PubMed

Ferguson, Frank T; Johnson, Natasha M; Nuth, Joseph A

2015-10-01

One possible origin of prebiotic organic material is that these compounds were formed via Fischer-Tropsch-type (FTT) reactions of carbon monoxide and hydrogen on silicate and oxide grains in the warm, inner-solar nebula. To investigate this possibility, an experimental system has been built in which the catalytic efficiency of different grain-analog materials can be tested. During such runs, the gas phase above these grain analogs is sampled using Fourier transform infrared (FT-IR) spectroscopy. To provide quantitative estimates of the concentration of these gases, a technique in which high-resolution spectra of the gases are calculated using the High-Resolution Transmission Molecular Absorption (HITRAN) database is used. Next, these spectra are processed via a method that mimics the processes giving rise to the instrumental line shape of the FT-IR spectrometer, including apodization, self-apodization, and broadening due to the finite resolution. The result is a very close match between the measured and computed spectra. This technique was tested using four major gases found in the FTT reactions: carbon monoxide, methane, carbon dioxide, and water. For the ranges typical of the FTT reactions, the carbon monoxide results were found to be accurate to within 5% and the remaining gases accurate to within 10%. These spectra can then be used to generate synthetic calibration data, allowing the rapid computation of the gas concentrations in the FTT experiments.

A CPV System with Static Linear Fresnel Lenses in a Greenhouse

NASA Astrophysics Data System (ADS)

Sonneveld, Piet; Zahn, Helmut; Swinkels, Gert-Jan

2010-10-01

A new CPV system with a static linear Fresnel lens, silicon PV module suitable for concentrated radiation and an innovative tracking system is integrated in a greenhouse covering. The basic idea of this horticultural application is to develop a greenhouse for pot plants (typical shadow plants) which don't like high direct radiation. Removing all direct radiation will block up to 77% of the solar energy, which will reduce the necessary cooling capacity. The solar energy focused on the Thermal Photovoltaic (PV/T) module generates electric and thermal energy. The PV/T module is tracked in the focal line and requires cooling due to the high heat load of the concentrated radiation (concentration factor of 50 times). All parts are integrated in a greenhouse with a size of about 36 m2. The electrical and thermal yield is determined for Dutch climate circumstances. Some measurements were performed with a PMMA linear Fresnel lens between double glass. Further improvement of the performance of the CPV-system is possible by using a PDMS lens directly laminated on glass and using AR-coated glass. This lens is developed with ZEMAX and the results of the Ray-tracing simulations are presented with the lens structure oriented in an upwards and downwards position. The best performance of the static linear Fresnel lens is achieved with upwards orientation of the lens structures. In practice this is only possible with the Fresnel lens placed between a double glass structure, which will keep the lens clean and free of water.

Perinatal collagen turnover markers in intrauterine growth restriction.

PubMed

Gourgiotis, Demetrios; Briana, Despina D; Georgiadis, Anestis; Boutsikou, Maria; Baka, Stavroula; Marmarinos, Antonios; Hassiakos, Demetrios; Malamitsi-Puchner, Ariadne

2012-09-01

To investigate bone and connective tissue collagen turnover in intrauterine growth restricted (IUGR) pregnancies, by determining circulating markers of type I collagen synthesis (carboxy-terminal propeptide of type I procollagen [PICP], representing bone formation) and degradation (cross-linked telopeptide of type I collagen [ICTP], representing bone resorption) as well as type III collagen synthesis (N-terminal propeptide of type-III procollagen [PIIINP], reflecting growth and tissue maturity). Plasma PICP, ICTP and PIIINP concentrations were measured in 40 mothers and their 20 asymmetric IUGR and 20 appropriate for gestational age (AGA) full-term fetuses and neonates on postnatal day 1-(N1) and 4-(N4). Fetal PICP, fetal and N4 ICTP, as well as fetal, N1 and N4 PIIINP concentrations were higher in the IUGR group (p ≤ 0.038, in all cases). In both groups, maternal PICP, ICTP and PIIINP concentrations were lower than fetal, N1 and N4 ones (p<0.001, in each case). Type I collagen turnover is enhanced in IUGR than AGA fetuses/neonates. Similarly, fetal/neonatal PIIINP concentrations are elevated in IUGR, probably due to stress, responsible for induction of tissue maturation, and/or to impaired excretory renal function, leading to reduced protein clearance. Fetal/neonatal PICP, ICTP and PIIINP concentrations are higher than maternal concentrations, possibly reflecting increased skeletal growth and collagen turnover in the former.

Statistics of Experiments on Cluster Formation and Transport in a Gravitational Field

NASA Technical Reports Server (NTRS)

Izmailov, Alexander F.; Myerson, Allan S.

1993-01-01

Metastable state relaxation in a gravitational field is investigated in the case of non-critical binary solutions. A relaxation description is presented in terms of the time-dependent Ginzburg-Landau formalism for a non-conserved order parameter. A new ansatz for solution of the corresponding partial nonlinear stochastic differential equation is discussed. It is proved that, for the supersaturated solution under consideration, the metastable state relaxation in a gravitational field leads to formation of solute concentration gradients due to the sedimentation of subcritical solute clusters. The pure discussion of the possible methods to compare theoretical results and experimental data related to solute sedimentation in a gravitational field is presented. It is shown that in order to describe these experiments it is necessary to deal both with the value of the solute concentration gradient and with its formation rate. The stochastic nature of the sedimentation process is shown.

Facile synthesis of fluorescence carbon dots from sweet potato for Fe3+ sensing and cell imaging.

PubMed

Shen, Jie; Shang, Shaoming; Chen, Xiuying; Wang, Dan; Cai, Yan

2017-07-01

In this study, a facile synthesis of fluorescence carbon dots (CDs) from sweet potato was performed through hydrothermal treatment. The obtained CDs with quantum yield of 8.64% have good dispersibility due to the soluble functional groups on their surfaces. The characterization of CDs was carried out and their possible formation mechanism was also discussed. In addition, the cytotoxicity results showed that the CDs exhibit non toxicity within 100μg/mL. At this concentration, the CDs were applied in cell imaging, indicating that they are promising fluorescent probes for biological imaging. In addition, the fluorescence of CDs was quenched by Fe 3+ with a linear concentration of 1 to 100μM, associated with the limit of detection of 0.32μM. Subsequently, the CDs were successfully applied for Fe 3+ probing in living cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Near-near-infrared thermal lens spectroscopy to assess overtones and combination bands of sulfentrazone pesticide.

PubMed

Ventura, M; Silva, J R; Andrade, L H C; Scorza Júnior, R P; Lima, S M

2018-01-05

Thermal lens spectroscopy (TLS) in the near-near-infrared region was used to explore the absorptions of overtones and combination bands of sulfentrazone (SFZ) herbicide diluted in methanol. This spectroscopic region was chosen in order to guarantee that only thermal lens effect is noted during the experimental procedure. The results showed that it was possible to detect very low concentrations (~2ng/μL) of SFZ in methanol by determining its thermal diffusivity or the absorption coefficient due to the 3ν(NH)+1δ(CH) combination band. This minimum SFZ concentration is the limit observed by chromatography method. The findings demonstrated that the TLS can be used for precise and accurate assessment of pesticides in ecosystems. Besides, the 3ν(NH)+1δ(CH) combination band at 960nm can be used as a marker for SFZ in methanol. Copyright © 2017 Elsevier B.V. All rights reserved.

Near-near-infrared thermal lens spectroscopy to assess overtones and combination bands of sulfentrazone pesticide

NASA Astrophysics Data System (ADS)

Ventura, M.; Silva, J. R.; Andrade, L. H. C.; Scorza Júnior, R. P.; Lima, S. M.

2018-01-01

Thermal lens spectroscopy (TLS) in the near-near-infrared region was used to explore the absorptions of overtones and combination bands of sulfentrazone (SFZ) herbicide diluted in methanol. This spectroscopic region was chosen in order to guarantee that only thermal lens effect is noted during the experimental procedure. The results showed that it was possible to detect very low concentrations ( 2 ng/μL) of SFZ in methanol by determining its thermal diffusivity or the absorption coefficient due to the 3ν(NH) + 1δ(CH) combination band. This minimum SFZ concentration is the limit observed by chromatography method. The findings demonstrated that the TLS can be used for precise and accurate assessment of pesticides in ecosystems. Besides, the 3ν(NH) + 1δ(CH) combination band at 960 nm can be used as a marker for SFZ in methanol.

Full down-conversion of amber-emitting phosphor-converted light-emitting diodes with powder phosphors and a long-wave pass filter.

PubMed

Oh, Jeong Rok; Cho, Sang-Hwan; Park, Hoo Keun; Oh, Ji Hye; Lee, Yong-Hee; Do, Young Rag

2010-05-24

This paper reports the possibility of a facile optical structure to realize a highly efficient monochromatic amber-emitting light-emitting diode (LED) using a powder-based phosphor-converted LED combined with a long-wave pass filter (LWPF). The capping of a blue-reflecting and amber-passing LWPF enhances both the amber emission from the silicate amber phosphor layer and the color purity due to the blocking and recycling of the pumping blue light from the InGaN LED. The enhancement of the luminous efficacy of the amber pc-LED with a LWPF (phosphor concentration 20 wt%, 39.4 lm/W) is 34% over that of an amber pc-LED without a LWPF (phosphor concentration 55 wt%, 29.4 lm/W) at 100 mA and a high color purity (>96%) with Commission International d'Eclairage (CIE) color coordinates of x=0.57 and y=0.42.

Study on leaching of pollutants from vegetable tanning residue.

PubMed

Mazumder, Debabrata; Biswas, Santosh; Bandyopadhyay, Pratip

2006-07-01

The processing of heavy leather employs the vegetable tanning method involving use of tan liquor. The solid residue of this vegetable tanning process aggravates the water pollution by means of leaching of tannin and other associatedpollutants. Tannin is a biologically resistant compound causing several problems in animal body. The present study dealt with the pollution hazard arising out of leaching of pollutants from the open dumped vegetable tanning residue by rainfall washing. The concerned pollutants were pH, Chemical Oxygen Demand (COD), tannin,sulfate and chloride concentration. To explore the possible extent of contamination of these pollutants in the leached water, two different masses (2 kg and 3 kg) of tanning residue were employed. The results of the study showed that there was a continuous release of pollutants from the vegetable tanning residue. Moreover, there was no regular variation in various pollutant concentrations in both the cases solely due to non-homogeneity of the residue.

Spasmolytic activity of trachylobanes ent-7α-acetoxytrachyloban-18-oic acid and ent-7α-hydroxytrachyloban-18-oic acid isolated from Xylopia langsdorfiana A. St-Hil. & Tul. (Annonaceae).

PubMed

Santos, Rosimeire F; Martins, Italo R R; Monteiro, Fabio de S; Travassos, Rafael de A; Janebro, Daniele I; Tavares, Josean F; Silva, Marcelo S; da Silva, Bagnólia A

2012-01-01

We aimed to investigate the possible spasmolytic activity of ent-7α-acetoxytrachyloban-18-oic acid (1) and ent-7α-hydroxytrachyloban-18-oic acid (2) on smooth muscle models. In male rat aorta and rat uterus, both diterpenes were unable to trigger spasmolytic action. However, 2 relaxed guinea-pig trachea: Compounds 1 and 2 antagonised, significantly and concentration-dependently, carbachol- and histamine-induced phasic contractions in guinea-pig ileum. Moreover, they induced a significant and concentration-dependent relaxation in pre-contracted (KCl, carbachol or histamine) guinea-pig ileum, with 2 being 15 times more potent than 1 in histamine-contracted ileum. These dissimilar results may be due to chemical differences between them. Thus, we demonstrated that 1 and 2 seem to be promising spasmolytic agents, although further studies are required to elucidate the spasmolytic action mechanism.

Dirty two-band superconductivity with interband pairing order

NASA Astrophysics Data System (ADS)

Asano, Yasuhiro; Sasaki, Akihiro; Golubov, Alexander A.

2018-04-01

We study theoretically the effects of random nonmagnetic impurities on the superconducting transition temperature T c in a two-band superconductor characterized by an equal-time s-wave interband pairing order parameter. Because of the two-band degree of freedom, it is possible to define a spin-triplet s-wave pairing order parameter as well as a spin-singlet s-wave order parameter. The former belongs to odd-band-parity symmetry class, whereas the latter belongs to even-band-parity symmetry class. In a spin-singlet superconductor, T c is insensitive to the impurity concentration when we estimate the self-energy due to the random impurity potential within the Born approximation. On the other hand in a spin-triplet superconductor, T c decreases with the increase of the impurity concentration. We conclude that Cooper pairs belonging to odd-band-parity symmetry class are fragile under the random impurity potential even though they have s-wave pairing symmetry.

Spatiotemporal Distribution of β-Amyloid in Alzheimer Disease Is the Result of Heterogeneous Regional Carrying Capacities.

PubMed

Whittington, Alex; Sharp, David J; Gunn, Roger N

2018-05-01

β-amyloid (Aβ) accumulation in the brain is 1 of 2 pathologic hallmarks of Alzheimer disease (AD), and the spatial distribution of Aβ has been studied extensively ex vivo. Methods: We applied mathematical modeling to Aβ in vivo PET imaging data to investigate competing theories of Aβ spread in AD. Results: Our results provided evidence that Aβ accumulation starts in all brain regions simultaneously and that its spatiotemporal distribution is due to heterogeneous regional carrying capacities (regional maximum possible concentration of Aβ) for the aggregated protein rather than to longer-term spreading from seed regions. Conclusion: The in vivo spatiotemporal distribution of Aβ in AD can be mathematically modeled using a logistic growth model in which the Aβ carrying capacity is heterogeneous across the brain but the exponential growth rate and time of half maximal Aβ concentration are constant. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

Contribution of indoor-generated particles to residential exposure

NASA Astrophysics Data System (ADS)

Isaxon, C.; Gudmundsson, A.; Nordin, E. Z.; Lönnblad, L.; Dahl, A.; Wieslander, G.; Bohgard, M.; Wierzbicka, A.

2015-04-01

The majority of airborne particles in residences, when expressed as number concentrations, are generated by the residents themselves, through combustion/thermal related activities. These particles have a considerably smaller diameter than 2.5 μm and, due to the combination of their small size, chemical composition (e.g. soot) and intermittently very high concentrations, should be regarded as having potential to cause adverse health effects. In this study, time resolved airborne particle measurements were conducted for seven consecutive days in 22 randomly selected homes in the urban area of Lund in southern Sweden. The main purpose of the study was to analyze the influence of human activities on the concentration of particles in indoor air. Focus was on number concentrations of particles with diameters <300 nm generated by indoor activities, and how these contribute to the integrated daily residential exposure. Correlations between these particles and soot mass concentration in total dust were also investigated. It was found that candle burning and activities related to cooking (using a frying pan, oven, toaster, and their combinations) were the major particle sources. The frequency of occurrence of a given concentration indoors and outdoors was compared for ultrafine particles. Indoor data was sorted into non-occupancy and occupancy time, and the occupancy time was further divided into non-activity and activity influenced time. It was found that high levels (above 104 cm-3) indoors mainly occur during active periods of occupancy, while the concentration during non-activity influenced time differs very little from non-occupancy time. Total integrated daily residential exposure of ultrafine particles was calculated for 22 homes, the contribution from known activities was 66%, from unknown activities 20%, and from background/non-activity 14%. The collected data also allowed for estimates of particle source strengths for specific activities, and for some activities it was possible to estimate correlations between the number concentration of ultrafine particles and the mass concentration of soot in total dust in 10 homes. Particle source strengths (for 7 specific activities) ranged from 1.6·1012 to 4.5·1012 min-1. The correlation between ultrafine particles and mass concentration of soot in total dust varied between 0.37 and 0.85, with an average of 0.56 (Pearson correlation coefficient). This study clearly shows that due to the importance of indoor sources, residential exposure to ultrafine particles cannot be characterized by ambient measurements alone.

Air pollution "holiday effect" resulting from the Chinese New Year

NASA Astrophysics Data System (ADS)

Tan, Pei-Hua; Chou, Chia; Liang, Jing-Yi; Chou, Charles C.-K.; Shiu, Chein-Jung

Our study was an attempt to conduct a comprehensive and systematical examination of the holiday effect, defined as the difference in air pollutant concentrations between holiday and non-holiday periods. This holiday effect can be applied to other countries with similar national or cultural holidays. Hourly and daily surface measurements of six major air pollutants from thirteen air quality monitoring stations of the Taiwan Environmental Protection Administration during the Chinese New Year (CNY) and non-Chinese New Year (NCNY) periods were used. We documented evidence of a "holiday effect", where air pollutant concentrations were significantly different between holidays (CNY) and non-holidays (NCNY), in the Taipei metropolitan area over the past thirteen years (1994-2006). The concentrations of NO x, CO, NMHC, SO 2 and PM 10 were lower in the CNY than in the NCNY period, while the variation in the concentration of O 3 was reversed, which was mainly due to the NO titration effect. Similar differences in these six air pollutants between the CNY and NCNY periods were also found in the diurnal cycle and in the interannual variation. For the diurnal cycle, a common traffic-related double-peak variation was observed in the NCNY period, but not in the CNY period. Impacts of dust storms were also observed, especially on SO 2 and PM 10 in the CNY period. In the 13-year period of 1994-2006, decreasing trends of NO x and CO in the NCNY period implied a possible reduction of local emissions. Increasing trends of SO 2 and PM 10 in the CNY period, on the other hand, indicated a possible enhancement of long-range transport. These two mechanisms weakened the holiday effect.

Biophysical modeling of in vitro and in vivo processes underlying regulated photoprotective mechanism in cyanobacteria.

PubMed

Shirshin, Evgeny A; Nikonova, Elena E; Kuzminov, Fedor I; Sluchanko, Nikolai N; Elanskaya, Irina V; Gorbunov, Maxim Y; Fadeev, Victor V; Friedrich, Thomas; Maksimov, Eugene G

2017-09-01

Non-photochemical quenching (NPQ) is a mechanism responsible for high light tolerance in photosynthetic organisms. In cyanobacteria, NPQ is realized by the interplay between light-harvesting complexes, phycobilisomes (PBs), a light sensor and effector of NPQ, the photoactive orange carotenoid protein (OCP), and the fluorescence recovery protein (FRP). Here, we introduced a biophysical model, which takes into account the whole spectrum of interactions between PBs, OCP, and FRP and describes the experimental PBs fluorescence kinetics, unraveling interaction rate constants between the components involved and their relative concentrations in the cell. We took benefit from the possibility to reconstruct the photoprotection mechanism and its parts in vitro, where most of the parameters could be varied, to develop the model and then applied it to describe the NPQ kinetics in the Synechocystis sp. PCC 6803 mutant lacking photosystems. Our analyses revealed  that while an excess of the OCP over PBs is required to obtain substantial PBs fluorescence quenching in vitro, in vivo the OCP/PBs ratio is less than unity, due to higher local concentration of PBs, which was estimated as ~10 -5 M, compared to in vitro experiments. The analysis of PBs fluorescence recovery on the basis of the generalized model of enzymatic catalysis resulted in determination of the FRP concentration in vivo close to 10% of the OCP concentration. Finally, the possible role of the FRP oligomeric state alteration in the kinetics of PBs fluorescence was shown. This paper provides the most comprehensive model of the OCP-induced PBs fluorescence quenching to date and the results are important for better understanding of the regulatory molecular mechanisms underlying NPQ in cyanobacteria.

Serial assessment of the physiological status of leatherback turtles (Dermochelys coriacea) during direct capture events in the northwestern Atlantic Ocean: comparison of post-capture and pre-release data.

PubMed

Innis, Charles J; Merigo, Constance; Cavin, Julie M; Hunt, Kathleen; Dodge, Kara L; Lutcavage, Molly

2014-01-01

The physiological status of seven leatherback turtles (Dermochelys coriacea) was assessed at two time points during ecological research capture events in the northwestern Atlantic Ocean. Data were collected as soon as possible after securing each turtle onboard the capture vessel and again immediately prior to release. Measured parameters included sea surface temperature, body temperature, morphometric data, sex, heart rate, respiratory rate and various haematological and blood biochemical variables. Results indicated generally stable physiological status in comparison to previously published studies of this species. However, blood pH and blood potassium concentrations increased significantly between the two time points (P = 0.0018 and P = 0.0452, respectively). Turtles were affected by a mild initial acidosis (mean [SD] temperature-corrected pH = 7.29 [0.07]), and blood pH increased prior to release (mean [SD] = 7.39 [0.07]). Initial blood potassium concentrations were considered normal (mean [SD] = 4.2 [0.9] mmol/l), but turtles experienced a mild to moderate increase in blood potassium concentrations during the event (mean [SD] pre-release potassium = 5.9 [1.7] mmol/l, maximum = 8.5 mmol/l). While these data support the general safety of direct capture for study of this species, the observed changes in blood potassium concentrations are of potential concern due to possible adverse effects of hyperkalaemia on cardiac function. The results of this study highlight the importance of physiological monitoring during scientific capture events. The results are also likely to be relevant to unintentional leatherback capture events (e.g. fisheries interactions), when interactions may be more prolonged or extreme.

Antibiotics impact plant traits, even at small concentrations

PubMed Central

Deloy, Andrea; Volkert, Anna Martina; Leonhardt, Sara Diana; Pufal, Gesine

2017-01-01

Abstract Antibiotics of veterinary origin are released to agricultural fields via grazing animals or manure. Possible effects on human health through the consumption of antibiotic exposed crop plants have been intensively investigated. However, information is still lacking on the effects of antibiotics on plants themselves, particularly on non-crop species, although evidence suggests adverse effects of antibiotics on growth and performance of plants. This study evaluated the effects of three major antibiotics, penicillin, sulfadiazine and tetracycline, on the germination rates and post-germinative traits of four plant species during ontogenesis and at the time of full development. Antibiotic concentrations were chosen as to reflect in vivo situations, i.e. concentrations similar to those detected in soils. Plant species included two herb species and two grass species, and represent two crop-species and two non-crop species commonly found in field margins, respectively. Germination tests were performed in climate chambers and effects on the remaining plant traits were determined in greenhouse experiments. Results show that antibiotics, even in small concentrations, significantly affect plant traits. These effects include delayed germination and post-germinative development. Effects were species and functional group dependent, with herbs being more sensitive to antibiotics then grasses. Responses were either negative or positive, depending on plant species and antibiotic. Effects were generally stronger for penicillin and sulfadiazine than for tetracycline. Our study shows that cropland species respond to the use of different antibiotics in livestock industry, for example, with delayed germination and lower biomass allocation, indicating possible effects on yield in farmland fertilized with manure containing antibiotics. Also, antibiotics can alter the composition of plant species in natural field margins, due to different species-specific responses, with unknown consequences for higher trophic levels. PMID:28439396

Analysis of the key enzymes of butyric and acetic acid fermentation in biogas reactors

PubMed Central

Gabris, Christina; Bengelsdorf, Frank R; Dürre, Peter

2015-01-01

This study aimed at the investigation of the mechanisms of acidogenesis, which is a key process during anaerobic digestion. To expose possible bottlenecks, specific activities of the key enzymes of acidification, such as acetate kinase (Ack, 0.23–0.99 U mg−1 protein), butyrate kinase (Buk, < 0.03 U mg−1 protein) and butyryl-CoA:acetate-CoA transferase (But, 3.24–7.64 U mg−1 protein), were determined in cell free extracts of biogas reactor content from three different biogas reactors. Furthermore, the detection of Ack was successful via Western blot analysis. Quantification of corresponding functional genes encoding Buk (buk) and But (but) was not feasible, although an amplification was possible. Thus, phylogenetic trees were constructed based on respective gene fragments. Four new clades of possible butyrate-producing bacteria were postulated, as well as bacteria of the genera Roseburia or Clostridium identified. The low Buk activity was in contrast to the high specific But activity in the analysed samples. Butyrate formation via Buk activity does barely occur in the investigated biogas reactor. Specific enzyme activities (Ack, Buk and But) in samples drawn from three different biogas reactors correlated with ammonia and ammonium concentrations (NH3 and NH4+-N), and a negative dependency can be postulated. Thus, high concentrations of NH3 and NH4+-N may lead to a bottleneck in acidogenesis due to decreased specific acidogenic enzyme activities. PMID:26086956

Hotspots, Lifelines, and the Safrr Haywired Earthquake Sequence

NASA Astrophysics Data System (ADS)

Ratliff, J. L.; Porter, K.

2014-12-01

Though California has experienced many large earthquakes (San Francisco, 1906; Loma Prieta, 1989; Northridge, 1994), the San Francisco Bay Area has not had a damaging earthquake for 25 years. Earthquake risk and surging reliance on smartphones and the Internet to handle everyday tasks raise the question: is an increasingly technology-reliant Bay Area prepared for potential infrastructure impacts caused by a major earthquake? How will a major earthquake on the Hayward Fault affect lifelines (roads, power, water, communication, etc.)? The U.S. Geological Survey Science Application for Risk Reduction (SAFRR) program's Haywired disaster scenario, a hypothetical two-year earthquake sequence triggered by a M7.05 mainshock on the Hayward Fault, addresses these and other questions. We explore four geographic aspects of lifeline damage from earthquakes: (1) geographic lifeline concentrations, (2) areas where lifelines pass through high shaking or potential ground-failure zones, (3) areas with diminished lifeline service demand due to severe building damage, and (4) areas with increased lifeline service demand due to displaced residents and businesses. Potential mainshock lifeline vulnerability and spatial demand changes will be discerned by superimposing earthquake shaking, liquefaction probability, and landslide probability damage thresholds with lifeline concentrations and with large-capacity shelters. Intersecting high hazard levels and lifeline clusters represent potential lifeline susceptibility hotspots. We will also analyze possible temporal vulnerability and demand changes using an aftershock shaking threshold. The results of this analysis will inform regional lifeline resilience initiatives and response and recovery planning, as well as reveal potential redundancies and weaknesses for Bay Area lifelines. Identified spatial and temporal hotspots can provide stakeholders with a reference for possible systemic vulnerability resulting from an earthquake sequence.

Antimicrobial and Antibiofilm Activity and Machine Learning Classification Analysis of Essential Oils from Different Mediterranean Plants against Pseudomonas aeruginosa.

PubMed

Artini, Marco; Patsilinakos, Alexandros; Papa, Rosanna; Božović, Mijat; Sabatino, Manuela; Garzoli, Stefania; Vrenna, Gianluca; Tilotta, Marco; Pepi, Federico; Ragno, Rino; Selan, Laura

2018-02-23

Pseudomonas aeruginosa is a ubiquitous organism and opportunistic pathogen that can cause persistent infections due to its peculiar antibiotic resistance mechanisms and to its ability to adhere and form biofilm. The interest in the development of new approaches for the prevention and treatment of biofilm formation has recently increased. The aim of this study was to seek new non-biocidal agents able to inhibit biofilm formation, in order to counteract virulence rather than bacterial growth and avoid the selection of escape mutants. Herein, different essential oils extracted from Mediterranean plants were analyzed for their activity against P. aeruginosa . Results show that they were able to destabilize biofilm at very low concentration without impairing bacterial viability. Since the action is not related to a bacteriostatic/bactericidal activity on P. aeruginosa , the biofilm change of growth in presence of the essential oils was possibly due to a modulation of the phenotype. To this aim, application of machine learning algorithms led to the development of quantitative activity-composition relationships classification models that allowed to direct point out those essential oil chemical components more involved in the inhibition of biofilm production. The action of selected essential oils on sessile phenotype make them particularly interesting for possible applications such as prevention of bacterial contamination in the community and in healthcare environments in order to prevent human infections. We assayed 89 samples of different essential oils as P. aeruginosa anti-biofilm. Many samples inhibited P. aeruginosa biofilm at concentrations as low as 48.8 µg/mL. Classification of the models was developed through machine learning algorithms.

Application of air classification and formulation to manage feedstock cost, quality and availability for bioenergy

DOE PAGES

Thompson, Vicki S.; Lacey, Jeffrey A.; Hartley, Damon; ...

2016-04-22

Biomass such as agricultural residues, energy crops and yard waste has significant potential to be used as renewable feedstocks for production of fuels, chemicals and energy. However, in a given location, biomass availability, cost and quality can vary markedly. Strategies to manage these traits must be identified and implemented so that consistent low-cost and high-quality feedstocks can be delivered to biorefineries year round. In this study, we examine air classification as a method to mitigate high ash concentrations in corn stover, switchgrass, and grass clippings. Formulation techniques were then used to produce blends that met ash quality and biomass quantitymore » specifications at the lowest possible cost for biopower and biochemical conversion applications. It was found that air classification can separate the biomass into light fractions which contain concentrated amounts of elemental ash components introduced through soil contamination such as sodium, alumina, silica, iron and titania; and heavy fractions that are depleted in these components and have relatively lower total ash content. Light fractions of corn stover and grass clippings were found to be suitable for combustion applications since they had less propensity to slag than the whole biomass material. The remaining heavy fractions of corn stover or grass clippings could then be blended with switchgrass to produce blends that met the 5% total ash specifications suggested for biochemical conversions. However, ternary blends of the three feedstocks were not possible due to the high ash content of grass clippings. Lastly, it was determined that air classification by itself was not suitable to prepare these feedstocks for pyrolysis due to high ash content.« less

Application of air classification and formulation to manage feedstock cost, quality and availability for bioenergy

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

Thompson, Vicki S.; Lacey, Jeffrey A.; Hartley, Damon

Biomass such as agricultural residues, energy crops and yard waste has significant potential to be used as renewable feedstocks for production of fuels, chemicals and energy. However, in a given location, biomass availability, cost and quality can vary markedly. Strategies to manage these traits must be identified and implemented so that consistent low-cost and high-quality feedstocks can be delivered to biorefineries year round. In this study, we examine air classification as a method to mitigate high ash concentrations in corn stover, switchgrass, and grass clippings. Formulation techniques were then used to produce blends that met ash quality and biomass quantitymore » specifications at the lowest possible cost for biopower and biochemical conversion applications. It was found that air classification can separate the biomass into light fractions which contain concentrated amounts of elemental ash components introduced through soil contamination such as sodium, alumina, silica, iron and titania; and heavy fractions that are depleted in these components and have relatively lower total ash content. Light fractions of corn stover and grass clippings were found to be suitable for combustion applications since they had less propensity to slag than the whole biomass material. The remaining heavy fractions of corn stover or grass clippings could then be blended with switchgrass to produce blends that met the 5% total ash specifications suggested for biochemical conversions. However, ternary blends of the three feedstocks were not possible due to the high ash content of grass clippings. Lastly, it was determined that air classification by itself was not suitable to prepare these feedstocks for pyrolysis due to high ash content.« less

K+-induced alterations in airway muscle responsiveness to electrical field stimulation

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

Murlas, C.; Ehring, G.; Suszkiw, J.

1986-07-01

We investigated possible pre- and postsynaptic effects of K+-induced depolarization on ferret tracheal smooth muscle (TSM) responsiveness to cholinergic stimulation. To assess electromechanical activity, cell membrane potential (Em) and tension (Tm) were simultaneously recorded in buffer containing 6, 12, 18, or 24 mM K+ before and after electrical field stimulation (EFS) or exogenous acetylcholine (ACh). In 6 mM K+, Em was -58.1 +/- 1.0 mV (mean +/- SE). In 12 mM K+, Em was depolarized to -52.3 +/- 0.9 mV, basal Tm did not change, and both excitatory junctional potentials and contractile responses to EFS at short stimulus duration weremore » larger than in 6 mM K+. No such potentiation occurred at a higher K+, although resting Em and Tm increased progressively above 12 mM K+. The sensitivity of ferret TSM to exogenous ACh appeared unaffected by K+. To determine whether the hyperresponsiveness in 12 mM K+ was due, in part, to augmented ACh release from intramural airway nerves, experiments were done using TSM preparations incubated with (3H)choline to measure (3H)ACh release at rest and during EFS. Although resting (3H)ACh release increased progressively in higher K+, release evoked by EFS was maximal in 12 mM K+ and declined in higher concentrations. We conclude that small elevations in the extracellular K+ concentration augment responsiveness of the airways, by increasing the release of ACh both at rest and during EFS from intramural cholinergic nerve terminals. Larger increases in K+ appear to be inhibitory, possibly due to voltage-dependent effects that occur both pre- and postsynaptically.« less

On Thermocapillary Mechanism of Spatial Separation of Metal Melts

NASA Astrophysics Data System (ADS)

Demin, V. A.; Mizev, A. I.; Petukhov, M. I.

2018-02-01

Theoretical research has been devoted to the study of binary metal melts behavior in a thin capillary. Earlier it has been found experimentally that unusually significant and quick redistribution of melts components takes place along capillary after the cooling. Numerical simulation of concentration-induced convection has been carried out to explain these experimental data. Two-component melt of both liquid metals filling vertical thin capillary with non-uniform temperature distribution on the boundaries is considered. It is assumed that the condition of absolute non-wetting is valid on the sidewalls. Because of this effect there is a free surface on vertical boundaries, where thermocapillary force is appeared due to the external longitudinal temperature gradient. It makes to move liquid elements at a big distance, compared with axial size of capillary. Effects of adsorption-desorption on the surface, thermal and concentration-capillary forces, convective motion in a volume and diffusion generate the large-scale circulation. This process includes the admixture carrying-out on the surface in the more hot higher part of the channel, its following transfer down along the boundary due to the thermocapillary force and its return in the volume over the desorption in the lower part of capillary. Intensity of motion and processes of adsorption-desorption on the free boundary have the decisive influence upon the formation of concentration fields and speed of components redistribution. Thus, one of the possible mechanisms of longitudinal division on components of liquid binary mixtures in thin channels has been demonstrated.

Effects of non-uniform root zone salinity on water use, Na+ recirculation, and Na+ and H+ flux in cotton

PubMed Central

Kong, Xiangqiang; Luo, Zhen; Dong, Hezhong; Eneji, A. Egrinya

2012-01-01

A new split-root system was established through grafting to study cotton response to non-uniform salinity. Each root half was treated with either uniform (100/100 mM) or non-uniform NaCl concentrations (0/200 and 50/150 mM). In contrast to uniform control, non-uniform salinity treatment improved plant growth and water use, with more water absorbed from the non- and low salinity side. Non-uniform treatments decreased Na+ concentrations in leaves. The [Na+] in the ‘0’ side roots of the 0/200 treatment was significantly higher than that in either side of the 0/0 control, but greatly decreased when the ‘0’ side phloem was girdled, suggesting that the increased [Na+] in the ‘0’ side roots was possibly due to transportation of foliar Na+ to roots through phloem. Plants under non-uniform salinity extruded more Na+ from the root than those under uniform salinity. Root Na+ efflux in the low salinity side was greatly enhanced by the higher salinity side. NaCl-induced Na+ efflux and H+ influx were inhibited by amiloride and sodium orthovanadate, suggesting that root Na+ extrusion was probably due to active Na+/H+ antiport across the plasma membrane. Improved plant growth under non-uniform salinity was thus attributed to increased water use, reduced leaf Na+ concentration, transport of excessive foliar Na+ to the low salinity side, and enhanced Na+ efflux from the low salinity root. PMID:22200663

MEAN-FIELD SOLAR DYNAMO MODELS WITH A STRONG MERIDIONAL FLOW AT THE BOTTOM OF THE CONVECTION ZONE

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

Pipin, V. V.; Kosovichev, A. G.

2011-09-01

This paper presents a study of kinematic axisymmetric mean-field dynamo models for the case of meridional circulation with a deep-seated stagnation point and a strong return flow at the bottom of the convection zone. This kind of circulation follows from mean-field models of the angular momentum balance in the solar convection zone. The dynamo models include turbulent sources of the large-scale poloidal magnetic field production due to kinetic helicity and a combined effect due to the Coriolis force and large-scale electric current. In these models the toroidal magnetic field, which is responsible for sunspot production, is concentrated at the bottommore » of the convection zone and is transported to low-latitude regions by a meridional flow. The meridional component of the poloidal field is also concentrated at the bottom of the convection zone, while the radial component is concentrated in near-polar regions. We show that it is possible for this type of meridional circulation to construct kinematic dynamo models that resemble in some aspects the sunspot magnetic activity cycle. However, in the near-equatorial regions the phase relation between the toroidal and poloidal components disagrees with observations. We also show that the period of the magnetic cycle may not always monotonically decrease with the increase of the meridional flow speed. Thus, for further progress it is important to determine the structure of the meridional circulation, which is one of the critical properties, from helioseismology observations.« less

Geochemical patterns of arsenic-enriched ground water in fractured, crystalline bedrock, Northport, Maine, USA

USGS Publications Warehouse

Lipfert, G.; Reeve, A.S.; Sidle, W.C.; Marvinney, R.

2006-01-01

High mean As concentrations of up to 26.6 ??mol/L (1990 ??g/L) occur in ground water collected from a fractured-bedrock system composed of sulfidic schist with granitic to dioritic intrusions. Sulfides in the bedrock are the primary source of the As in the ground water, but the presence of arsenopyrite in rock core retrieved from a borehole with As concentrations in the ground water barely above the detection limit of 2.0 ??mol/L, shows that there are complicating factors. Chemical analyses of water from 35 bedrock wells throughout a small watershed reveal spatial clustering of wells with high As concentrations. Stiff diagrams and box plots distinguish three distinct types; calcium-bicarbonate-dominated water with low As concentrations (CaHCO 3 type), sodium-bicarbonate-dominated water with moderately high As concentrations (NaHCO3 type), and calcium-bicarbonate-dominated water with very high As concentrations (High-As type). It is proposed that differences in recharge area and ground-water evolution, and possible bedrock composition difference are responsible for the chemical distinctions within the watershed. Lack of correlation of As concentrations with pH indicates that desorption of As is an insignificant control on As concentration. Correlations of As concentrations with Fe and redox parameters indicates that reductive dissolution of Fe(III) oxyhydroxides may play a role in the occurrence of high As concentrations in the NaHCO3 and High-As type water. The oxidation of sulfide minerals occurs within the ground-water system and is ultimately responsible for the existence of As in the ground water, but there is no correlation between As and SO4 concentrations, probably due to precipitation of Fe(III) oxyhydroxides and adsorption of As under oxidizing conditions. Crown Copyright ?? 2006 Published by Elsevier Ltd. All rights reserved.

Satellite Investigation of Atmospheric Metal Deposition During Meteor Showers

NASA Astrophysics Data System (ADS)

Correira, J.; Aikin, A. C.; Grebowsky, J. M.

2008-12-01

Using the nadir-viewing Global Ozone Measuring Experiment (GOME) UV/VIS spectrometer on the ERS-2 satellite, we investigate short term variations in the magnesium column densities and any connection to possible enhanced mass deposition during a meteor shower. We derive a time dependent mass flux rate due to meteor showers using published estimates of mass density and activity profiles of meteor showers. An average daily mass flux rate is also calculated and used as a baseline against which calculated shower mass flux rates are compared. These theoretical mass flux rates are then compared with GOME derived metal column densities from the years 1996 - 2001.There appears to be little correlation between theoretical mass flux rates and changes in the Mg and Mg+ metal column densities. A possible explanation for the lack of a shower related increase in metal concentrations may be differences in the mass regimes dominating the average background mass flux and shower mass flux.

Regional climate impacts of a possible future grand solar minimum.

PubMed

Ineson, Sarah; Maycock, Amanda C; Gray, Lesley J; Scaife, Adam A; Dunstone, Nick J; Harder, Jerald W; Knight, Jeff R; Lockwood, Mike; Manners, James C; Wood, Richard A

2015-06-23

Any reduction in global mean near-surface temperature due to a future decline in solar activity is likely to be a small fraction of projected anthropogenic warming. However, variability in ultraviolet solar irradiance is linked to modulation of the Arctic and North Atlantic Oscillations, suggesting the potential for larger regional surface climate effects. Here, we explore possible impacts through two experiments designed to bracket uncertainty in ultraviolet irradiance in a scenario in which future solar activity decreases to Maunder Minimum-like conditions by 2050. Both experiments show regional structure in the wintertime response, resembling the North Atlantic Oscillation, with enhanced relative cooling over northern Eurasia and the eastern United States. For a high-end decline in solar ultraviolet irradiance, the impact on winter northern European surface temperatures over the late twenty-first century could be a significant fraction of the difference in climate change between plausible AR5 scenarios of greenhouse gas concentrations.

Toxicological and analytical investigations of noni (Morinda citrifolia) fruit juice.

PubMed

Westendorf, Johannes; Effenberger, Katharina; Iznaguen, Hassan; Basar, Simla

2007-01-24

Morinda citrifolia (noni) is known to contain genotoxic anthraquinones in the roots. Because of the widespread use of noni juice, the possible genotoxic risk was examined through a battery of short-term tests. Noni juice was also chemically analyzed for the possible presence of anthraquinones. Noni juice extract in the Salmonella microsome assay showed a slight mutagenic effect in strain TA1537, due to the presence of flavonoids. No mutagenicity was observed in the mammalian mutagenicity test with V79 Chinese hamster fibroblasts. Rats treated with a noni juice concentrate did not show DNA repair synthesis (UDS) in primary rat hepatocytes, nor could DNA adducts or DNA strand breaks be observed. HPLC analysis of noni juice for anthraquinones was negative, with a sensitivity of <1 ppm. In summary, chemical analysis and genotoxicity tests reveal that noni juice does not have a genotoxic potential and that genotoxic anthraquinones do not exist in noni juice.

Numerical study of the effects of physical parameters on the dynamic fuel retention in tungsten materials

NASA Astrophysics Data System (ADS)

Sang, Chaofeng; Sun, Jizhong; Bonnin, Xavier; Dai, Shuyu; Hu, Wanpeng; Wang, Dezhen

2014-12-01

Effects of different possible values of physical parameters on the fuel retention in tungsten (W) materials are studied in this work since W is considered as the primary plasma-facing surface material and fuel retention is a critical issue for next-step fusion devices. The upgraded Hydrogen Isotope Inventory Processes Code is used to conduct the study. First, the inventories of hydrogen isotopes (HI) inside W with different possible values of diffusivities and recombination rate coefficients are studied; then the influences of uncertainties in diffusivity, trap concentration, and recombination rate on the effective diffusion are also analyzed. Finally, an illustration of effective diffusion on the permeation and inventory is given. The enhancements of HI permeation flux and inventory in bulk W due to the presence of a carbide WxC layer on the PFS are explained.

Nonparametric estimation of groundwater residence time distributions: What can environmental tracer data tell us about groundwater residence time?

NASA Astrophysics Data System (ADS)

McCallum, James L.; Engdahl, Nicholas B.; Ginn, Timothy R.; Cook, Peter. G.

2014-03-01

Residence time distributions (RTDs) have been used extensively for quantifying flow and transport in subsurface hydrology. In geochemical approaches, environmental tracer concentrations are used in conjunction with simple lumped parameter models (LPMs). Conversely, numerical simulation techniques require large amounts of parameterization and estimated RTDs are certainly limited by associated uncertainties. In this study, we apply a nonparametric deconvolution approach to estimate RTDs using environmental tracer concentrations. The model is based only on the assumption that flow is steady enough that the observed concentrations are well approximated by linear superposition of the input concentrations with the RTD; that is, the convolution integral holds. Even with large amounts of environmental tracer concentration data, the entire shape of an RTD remains highly nonunique. However, accurate estimates of mean ages and in some cases prediction of young portions of the RTD may be possible. The most useful type of data was found to be the use of a time series of tritium. This was due to the sharp variations in atmospheric concentrations and a short half-life. Conversely, the use of CFC compounds with smoothly varying atmospheric concentrations was more prone to nonuniqueness. This work highlights the benefits and limitations of using environmental tracer data to estimate whole RTDs with either LPMs or through numerical simulation. However, the ability of the nonparametric approach developed here to correct for mixing biases in mean ages appears promising.

Dissolved Organophosphate Esters and Polybrominated Diphenyl Ethers in Remote Marine Environments: Arctic Surface Water Distributions and Net Transport through Fram Strait.

PubMed

McDonough, Carrie A; De Silva, Amila O; Sun, Caoxin; Cabrerizo, Ana; Adelman, David; Soltwedel, Thomas; Bauerfeind, Eduard; Muir, Derek C G; Lohmann, Rainer

2018-06-05

Organophosphate esters (OPEs) have been found in remote environments at unexpectedly high concentrations, but very few measurements of OPE concentrations in seawater are available, and none are available in subsurface seawater. In this study, passive polyethylene samplers (PEs) deployed on deep-water moorings in the Fram Strait and in surface waters of Canadian Arctic lakes and coastal sites were analyzed for a suite of common OPEs. Total OPEs ( ∑ 11 OPE) at deep-water sites were dominated by chlorinated OPEs, and ranged from 6.3 to 440 pg/L. Concentrations were similar in eastern and western Fram Strait. Chlorinated OPEs were also dominant in Canadian Arctic surface waters (mean concentration ranged from < DL to 4400 pg/L), while nonhalogenated alkyl/aryl-substituted OPEs remained low (1.3-55 pg/L), possibly due to the greater long-range transport potential of chlorinated OPEs. Polybrominated diphenyl ethers (PBDEs) were found at much lower concentrations than OPEs (

Electrochemical treatment of iopromide under conditions of reverse osmosis concentrates--elucidation of the degradation pathway.

PubMed

Lütke Eversloh, C; Henning, N; Schulz, M; Ternes, T A

2014-01-01

Application of reverse osmosis for the reuse of treated wastewater on the one hand offers a way to provide high quality effluent waters. On the other hand reverse osmosis concentrates exhibiting highly concentrated contaminants are produced simultaneously. Electrochemical treatment of those concentrates is regarded as one possible answer to the problem of their disposal into surface waters. Nevertheless, due to the diversity of direct and indirect degradation processes during electrolysis, special care has to be taken about the formation of toxic transformation products (TPs). In this study the electrochemical transformation of the X-ray contrast medium iopromide was investigated as a representative of biologically persistent compounds. For this purpose, anodic oxidation at boron doped diamond as well as cathodic reduction using a platinum electrode were considered. Kinetic analyses revealed a transformation of 100 μM iopromide with first order kinetic constants between 0.6 and 1.6 × 10(-4) s(-1) at the beginning and a subsequent increase of the reaction order due to the influence of secondary oxidants formed during electrolysis. Mineralization up to 96% was achieved after about 7.5 h. At shorter treatment times several oxidatively and reductively formed transformation products were detected, whereas deiodinated iopromide represented the major fraction. Nevertheless, the latter exhibited negligible toxicological relevance according to tests on vibrio fisheri. Additional experiments utilizing a divided cell setup enabled the elucidation of the transformation pathway, whereas emerging TPs could be identified by means of high resolution mass spectrometry and MS(n)-fragmentations. During electrolysis the iodine released from Iopromide was found to 90% as iodide and to 10% as iodate even in the open cell experiments, limiting the potential formation of toxic iodo-disinfection by-products. Chlorinated TPs were not found. Copyright © 2013. Published by Elsevier Ltd.

Implications of stillage land disposal: a critical review on the impacts of fertigation.

PubMed

Fuess, Lucas Tadeu; Garcia, Marcelo Loureiro

2014-12-01

Stillage is the main wastewater from ethanol production, generated specifically in the step of distillation. Regardless the feedstock, stillage contains high concentrations of organic matter, potassium and sulfates, as well as acidic and corrosive characteristics. Currently almost the entire volume of stillage generated in Brazilian distilleries is directed to the fertigation of sugarcane fields, due to its fertilizer character. However, the polluting potential of stillage characterizes its land disposal as problematic, considering probable negative impacts on the soil structure and water resources in case of excessive dosages. Since the literature lacks critical content describing clearly the cons related to the reuse of stillage in agriculture in the long-term, this review aimed to assess the real polluting potential of stillage, and the implications of its land disposal and/or discharge into water bodies. Evidence from the literature indicate that the main obstacles to reuse stillage in natura include risks of soil salinization; clogging of pores, reduction in the microbial activity and the significant depletion of dissolved oxygen concentrations in water bodies; contamination per nitrates and eutrophication; soil structure destabilization due to high concentrations of potassium and sodium; and, possible acidification of soil and water resources, considering the low pH of stillage (∼4,5). Toxic metals, such as cadmium, lead, copper, chromium and nickel, were also identified in concentrations above the recommended limits in stillage samples, increasing risks to human health (e.g. carcinogenic potential) and to crops (e.g. productivity loss). In short, although some studies report benefits from the land application of stillage, its treatment prior to disposal is essential to make fertigation an environmentally suitable practice. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessing determinants of maternal blood concentrations for persistent organic pollutants and metals in the eastern and western Canadian Arctic.

PubMed

Curren, Meredith S; Liang, Chun Lei; Davis, Karelyn; Kandola, Kami; Brewster, Janet; Potyrala, Mary; Chan, Hing Man

2015-09-15

Aboriginal peoples in the Canadian Arctic are exposed to persistent organic pollutants (POPs) and metals mainly through their consumption of a traditional diet of wildlife items. Recent studies indicate that many human chemical levels have decreased in the north, likely due to a combination of reduced global chemical emissions, dietary shifts, and risk mitigation efforts by local health authorities. Body burdens for chemicals in mothers can be further offset by breastfeeding, parity, and other maternal characteristics. We have assessed the impact of several dietary and maternal covariates following a decade of awareness of the contaminant issue in northern Canada, by performing multiple stepwise linear regression analyses from blood concentrations and demographic variables for 176 mothers recruited from Nunavut and the Northwest Territories during the period 2005-2007. A significant aboriginal group effect was observed for the modeled chemicals, except for lead and cadmium, after adjusting for covariates. Further, blood concentrations for POPs and metals were significantly associated with at least one covariate of older age, fewer months spent breastfeeding, more frequent eating of traditional foods, or smoking during pregnancy. Cadmium had the highest explained variance (72.5%) from just two significant covariates (current smoking status and parity). Although Inuit participants from the Northwest Territories consumed more traditional foods in general, Inuit participants from coastal communities in Nunavut continued to demonstrate higher adjusted blood concentrations for POPs and metals examined here. While this is due in part to a higher prevalence of marine mammals in the eastern Arctic diet, it is possible that other aboriginal group effects unrelated to diet may also contribute to elevated chemical body burdens in Canadian Arctic populations. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

High concentration of vitamin E decreases thermosensation and thermotaxis learning and the underlying mechanisms in the nematode Caenorhabditis elegans.

PubMed

Li, Yiping; Li, Yinxia; Wu, Qiuli; Ye, Huayue; Sun, Lingmei; Ye, Boping; Wang, Dayong

2013-01-01

α-tocopherol is a powerful liposoluble antioxidant and the most abundant isoform of vitamin E in the body. Under normal physiological conditions, adverse effects of relatively high concentration of vitamin E on organisms and the underlying mechanisms are still largely unclear. In the present study, we used the nematode Caenorhabditis elegans as an in vivo assay system to investigate the possible adverse effects of high concentration of vitamin E on thermosensation and thermotaxis learning and the underlying mechanisms. Our data show that treatment with 100-200 µg/mL of vitamin E did not noticeably influence both thermosensation and thermotaxis learning; however, treatment with 400 µg/mL of vitamin E altered both thermosensation and thermotaxis learning. The observed decrease in thermotaxis learning in 400 µg/mL of vitamin E treated nematodes might be partially due to the moderate but significant deficits in thermosensation, but not due to deficits in locomotion behavior or perception to food and starvation. Treatment with 400 µg/mL of vitamin E did not noticeably influence the morphology of GABAergic neurons, but significantly decreased fluorescent intensities of the cell bodies in AFD sensory neurons and AIY interneurons, required for thermosensation and thermotaxis learning control. Treatment with 400 µg/mL of vitamin E affected presynaptic function of neurons, but had no remarkable effects on postsynaptic function. Moreover, promotion of synaptic transmission by activating PKC-1 effectively retrieved deficits in both thermosensation and thermotaxis learning induced by 400 µg/mL of vitamin E. Therefore, relatively high concentrations of vitamin E administration may cause adverse effects on thermosensation and thermotaxis learning by inducing damage on the development of specific neurons and presynaptic function under normal physiological conditions in C. elegans.

Impact of agriculture and land use on nitrate contamination in groundwater and running waters in central-west Poland.

PubMed

Lawniczak, Agnieszka Ewa; Zbierska, Janina; Nowak, Bogumił; Achtenberg, Krzysztof; Grześkowiak, Artur; Kanas, Krzysztof

2016-03-01

Protected areas due to their long-term protection are expected to be characterized by good water quality. However, in catchments where arable fields dominate, the impact of agriculture on water pollution is still problematic. In Poland, recently, the fertilization level has decreased, mostly for economic reasons. However, this applies primarily to phosphorus and potassium. In order to evaluate the impact of agriculture on water quality in a protected area with a high proportion of arable fields in the aspect of level and type of fertilization, complex monitoring has been applied. The present study was carried out in Wielkopolska National Park and its buffer zone, which are protected under Natura 2000 as Special Areas of Conservation and Special Protection Areas. The aim of the study were (1) to assess the impact of agriculture, with special attention on fertilization, on groundwater, and running water quality and (2) to designate priority areas for implementing nitrogen reduction measures in special attention on protected areas. In our study, high nitrogen concentrations in groundwater and surface waters were detected in the agricultural catchments. The results demonstrate that in the watersheds dominated by arable fields, high nitrogen concentrations in groundwater were measured in comparison to forestry catchments, where high ammonium concentrations were observed. The highest nitrogen concentrations were noted in spring after winter freezing, with a small cover of vegetation, and in the areas with a high level of nitrogen application. In the studied areas, both in the park and its buffer zone, unfavorable N:P and N:K ratios in supplied nutrients were detected. Severe shortage of phosphorus and potassium in applied fertilizers is one of the major factors causing leaching of nitrogen due to limited possibilities of its consumption by plants.

Functional roles of the major chloroplast lipids in the violaxanthin cycle.

PubMed

Yamamoto, Harry Y

2006-08-01

Monogalactosyldiacylglyceride (MGDG) and digalactosyldiacylglyceride (DGDG) are the major membrane lipids of chloroplasts. The question of the specialized functions of these unique lipids has received limited attention. One function is to support violaxanthin de-epoxidase (VDE) activity, an enzyme of the violaxanthin cycle. To understand better the properties of this system, the effects of galactolipids and phosphatidylcholines on VDE activity were examined by two independent methods. The results show that the micelle-forming lipid (MGDG) and bilayer forming lipids (DGDG and phosphatidylcholines) support VDE activity differently. MGDG supported rapid and complete de-epoxidation starting at a threshold lipid concentration (10 microM) coincident with complete solubilization of violaxanthin. In contrast, DGDG supported slow but nevertheless complete to nearly complete de-epoxidation at a lower lipid concentration (6.7 microM) that did not completely solubilize violaxanthin. Phosphotidylcholines showed similar effects as DGDG except that de-epoxidation was incomplete. Since VDE requires solubilized violaxanthin, aggregated violaxanthin in DGDG at low concentration must become solubilized as de-epoxidation proceeds. High lipid concentrations had lower activity possibly due to formation of multilayered structures (liposomes) that restrict accessibility of violaxanthin to VDE. MGDG micelles do not present such restrictions. The results indicate VDE operates throughout the lipid phase of the single bilayer thylakoid membrane and is not limited to putative MGDG micelle domains. Additionally, the results also explain the differential partitioning of violaxanthin between the envelope and thylakoid as due to the relative solubilities of violaxanthin and zeaxanthin in MGDG, DGDG and phospholipids. The violaxanthin cycle is hypothesized to be a linked system of the thylakoid and envelope for signal transduction of light stress.

Monitoring of atmospheric gaseous and particulate polycyclic aromatic hydrocarbons in South African platinum mines utilising portable denuder sampling with analysis by thermal desorption-comprehensive gas chromatography-mass spectrometry.

PubMed

Geldenhuys, G; Rohwer, E R; Naudé, Y; Forbes, P B C

2015-02-06

Concentrations of diesel particulate matter and polycyclic aromatic hydrocarbons (PAHs) in platinum mine environments are likely to be higher than in ambient air due to the use of diesel machinery in confined environments. Airborne PAHs may be present in gaseous or particle phases each of which has different human health impacts due to their ultimate fate in the body. Here we report on the simultaneous sampling of both phases of airborne PAHs for the first time in underground platinum mines in South Africa, which was made possible by employing small, portable denuder sampling devices consisting of two polydimethylsiloxane (PDMS) multi-channel traps connected in series separated by a quartz fibre filter, which only require small, battery operated portable personal sampling pumps for air sampling. Thermal desorption coupled with comprehensive gas chromatography-mass spectrometry (TD-GC×GC-TofMS) was used to analyse denuder samples taken in three different platinum mines. The samples from a range of underground environments revealed that PAHs were predominantly found in the gas phase with naphthalene and mono-methylated naphthalene derivatives being detected at the highest concentrations ranging from 0.01 to 18 μg m(-3). The particle bound PAHs were found in the highest concentrations at the idling load haul dump vehicle exhausts with a dominance of fluoranthene and pyrene. Particle associated PAH concentrations ranged from 0.47 to 260 ng m(-3) and included benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene. This work highlights the need to characterise both phases in order to assess occupational exposure to PAHs in this challenging sampling environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Understanding recent climate change.

PubMed

Serreze, Mark C

2010-02-01

The Earth's atmosphere has a natural greenhouse effect, without which the global mean surface temperature would be about 33 degrees C lower and life would not be possible. Human activities have increased atmospheric concentrations of carbon dioxide, methane, and other gases in trace amounts. This has enhanced the greenhouse effect, resulting in surface warming. Were it not for the partly offsetting effects of increased aerosol concentrations, the increase in global mean surface temperature over the past 100 years would be larger than observed. Continued surface warming through the 21st century is inevitable and will likely have widespread ecological impacts. The magnitude and rate of warming for the global average will be largely dictated by the strength and direction of climate feedbacks, thermal inertia of the oceans, the rate of greenhouse gas emissions, and aerosol concentrations. Because of regional expressions of climate feedbacks, changes in atmospheric circulation, and a suite of other factors, the magnitude and rate of warming and changes in other key climate elements, such as precipitation, will not be uniform across the planet. For example, due to loss of its floating sea-ice cover, the Arctic will warm the most.

Anaerobic Digestion of Organic Fraction from Hydrothermal Liquefied Algae Wastewater Byproduct

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

Fernandez, Sebastian; Srinivas, Keerthi; Schmidt, Andrew J.

We present that the wastewater stream from hydrothermal liquefaction (HTL) process used in biofuel production, contains a large amounts of organic compounds where several can be regarded as environmentally hazardous and requires significant treatment before disposal. In this study, semi-continuous anaerobic digestion is used to degrade the organic fraction of wastewater streams from HTL of the algae Tetraselmis (AgTet) and Chlorella (AgChlr). Results indicated high methane yields at 20-30% (v/v) HTL wastewater together with clarified manure, producing 327.2 mL/gVS in (or volatile solids in feed) for AgTet and 263.4 mL/gVS in for AgChlr. There was a significant reduction in methanemore » production at concentrations higher than 40% (v/v) HTL wastewater in the feed, possibly due to the accumulation of chloride salts or inhibitory compounds such as pyridines, piperidines and pyrrolidines. In conclusion, this was further confirmed by comparing COD, salt and the ammonia concentrations of the effluents after anaerobic digestion at different concentrations of wastewater in manure.« less

Involvement of CYP 3A5 In the Interaction Between Tacrolimus and Nicardipine: A Case Report.

PubMed

Sassi, Mouna B; Gaies, Emna; Salouage, Issam; Trabelsi, Sameh; Lakhal, Mohamed; Klouz, Anis

2015-01-01

Tacrolimus is a calcineurin inhibitor primarily metabolized by CYP3A4 and secondarily by CYP3A5. Several drugs can modify tacrolimus blood levels as calcium channel blockers (CCBs). Interaction with nicardipine was reported in some cases. A man with a history of malignant arterial hypertension treated with nicardipine, underwent kidney transplantation. After transplantation, he was treated with tacrolimus, mycophenolate mofetil and corticoids. Therapeutic drug monitoring of tacrolimus was done regularly showing a mean trough concentration (C0) of 24.39 ng/mL with some concentrations reaching 52 ng/mL. After changing nicardipine by prazosine, the first tacrolimus C0 after stopping nicardipine was 3.2 ng/mL. Increase of tacrolimus trough concentrations is due to the inhibition of CYP3A4. Very high levels of tacrolimus suggest the non expression of CYP3A5. Thus, because of the possible lack of the secondary pathway, therapeutic drug monitoring of tacrolimus is highly recommended at the introduction of CCBs and also at its stopping.

Mechanisms and effects of arsanilic acid on antibiotic resistance genes and microbial communities during pig manure digestion.

PubMed

Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Zhang, Li; Guo, Ai-Yun

2017-06-01

High concentrations of residual arsanilic acid occur in pig manure due to its use in feed to promote growth and control diseases. This study compared the effects of arsanilic acid at three concentrations (0, 325, and 650mg/kg dry pig manure) on the abundance of antibiotic resistance genes (ARGs) and the microbial community during anaerobic digestion. Addition of 650mg/kg arsanilic acid enhanced the absolute abundances of tetC, sul2, ermB, and gyrA more than twofold in the digestion product. Redundancy analysis indicated that the change in the microbial community structure was the main driver of variation in the ARGs profile. The As resistance gene arsC co-occurred with four ARGs and intI1, possibly causing the increase in ARGs under pressure by arsanilic acid. High arsanilic acid concentrations can increase the risk of ARGs occurring in anaerobic digestion products. The amount of arsanilic acid used as a feed additive should be controlled. Copyright © 2017. Published by Elsevier Ltd.

Rheological properties of concentrated, nonaqueous silicon nitride suspensions

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

Bergstroem, L.

1996-12-01

The rheological properties of nonaqueous silicon nitride powder suspensions have been investigated using steady shear and viscoelastic measurements. The polymeric dispersant, Hypermer KD-3, adsorbed strongly on the powder surfaces, and colloidally stable, fluid suspensions up to a volume fraction of {Phi} = 0.50 could be prepared. The concentrated suspensions all displayed a shear thinning behavior which could be modeled using the high shear form of the Cross equation. The viscoelastic response at high concentrations was dominated by particle interactions, probably due to interpenetration of the adsorbed polymer layers, and a thickness of the adsorbed Hypermer KD-3 layer, {Delta} {approx} 10more » nm, was estimated. The volume fraction dependences of the high shear viscosity of three different silicon nitride powders were compared and the differences, analyzed by using a modified Krieger-Dougherty model, were related to effective volume effects and the physical characteristics of the powders. The significantly lower maximum volume fraction, {Phi}{sub m} = 0.47, of the SN E-10 powder was referred to the narrow particle size distribution and the possibility of an unfavorable particle morphology.« less

Quantitative Analysis of Single and Mix Food Antiseptics Basing on SERS Spectra with PLSR Method

NASA Astrophysics Data System (ADS)

Hou, Mengjing; Huang, Yu; Ma, Lingwei; Zhang, Zhengjun

2016-06-01

Usage and dosage of food antiseptics are very concerned due to their decisive influence in food safety. Surface-enhanced Raman scattering (SERS) effect was employed in this research to realize trace potassium sorbate (PS) and sodium benzoate (SB) detection. HfO2 ultrathin film-coated Ag NR array was fabricated as SERS substrate. Protected by HfO2 film, the SERS substrate possesses good acid resistance, which enables it to be applicable in acidic environment where PS and SB work. Regression relationship between SERS spectra of 0.3~10 mg/L PS solution and their concentration was calibrated by partial least squares regression (PLSR) method, and the concentration prediction performance was quite satisfactory. Furthermore, mixture solution of PS and SB was also quantitatively analyzed by PLSR method. Spectrum data of characteristic peak sections corresponding to PS and SB was used to establish the regression models of these two solutes, respectively, and their concentrations were determined accurately despite their characteristic peak sections overlapping. It is possible that the unique modeling process of PLSR method prevented the overlapped Raman signal from reducing the model accuracy.

Adverse effects of concentrated green tea extracts.

PubMed

Schönthal, Axel H

2011-06-01

A myriad of health claims are being made in favor of the consumption of green tea. However, mostly due to the easy availability and greater than ever popularity of highly concentrated green tea extracts, sometimes combined with an attitude of more-is-better, certain health risks of green tea consumption have begun to emerge. Among such risks are the possibility of liver damage, the potential to interact with prescription drugs to alter their therapeutic efficacy, and the chance to cause harm when combined with other highly popular herbal remedies. This review will summarize documented examples of adverse effects of green tea in humans, and will discuss risks of copious consumption of highly concentrated green tea extracts as indicated by studies in animals. While there is no intention to minimize any of the scientifically established benefits of the use of green tea, the purpose of this review is to focus primarily on the potential for adverse effects and raise awareness of the rare, yet under-appreciated risks. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A comparative human health risk assessment of p-dichlorobenzene-based toilet rimblock products versus fragrance/surfactant-based alternatives.

PubMed

Aronson, Dallas B; Bosch, Stephen; Gray, D Anthony; Howard, Philip H; Guiney, Patrick D

2007-10-01

A comparison of the human health risk to consumers using one of two types of toilet rimblock products, either a p-dichlorobenzene-based rimblock or two newer fragrance/surfactant-based alternatives, was conducted. Rimblock products are designed for global use by consumers worldwide and function by releasing volatile compounds into indoor air with subsequent exposure presumed to be mainly by inhalation of indoor air. Using the THERdbASE exposure model and experimentally determined emission data, indoor air concentrations and daily intake values were determined for both types of rimblock products. Modeled exposure concentrations from a representative p-dichlorobenzene rimblock product are an order of magnitude higher than those from the alternative rimblock products due to its nearly pure composition and high sublimation rate. Lifetime exposure to p-dichlorobenzene or the subset of fragrance components with available RfD values is not expected to lead to non-cancer-based adverse health effects based on the exposure concentrations estimated using the THERdbASE model. A similar comparison of cancer-based effects was not possible as insufficient data were available for the fragrance components.

A comparison of two cloudwater/fogwater collectors: The rotating arm collector and the caltech active strand cloudwater collector

NASA Astrophysics Data System (ADS)

Collett, Jeffrey L.; Daube, Bruce C.; Munger, J. William; Hoffmann, Michael R.

A side-by-side comparison of the Rotating Arm Collector (RAC) and the Caltech Active Strand Cloudwater Collector (CASCC) was conducted at an elevated coastal site near the eastern end of the Santa Barbara Channel in southern California. The CASCC was observed to collect cloudwater at rates of up to 8.5 ml min -1. The ratio of cloudwater collection rates was found to be close to the theoretical prediction of 4.2:1 (CASCC:RAC) over a wide range of liquid water contents (LWC). At low LWC, however, this ratio climbed rapidly, possibly reflecting a predominance of small droplets under these conditions, coupled with a greater collection efficiency of small droplets by the CASCC. Cloudwater samples collected by the RAC had significantly higher concentrations of Na +, Ca 2+, Mg 2+ and Cl - than those collected by the CASCC. These higher concentrations may be due to differences in the chemical composition of large vs small droplets. No significant differences were observed in concentrations of NO 3-, SO 42- or NH 4+ in samples collected by the two instruments.

Remote sensing of air pollution over large European cities by lidar

NASA Astrophysics Data System (ADS)

Koelsch, Hans J.; Kolenda, Juergen; Rairoux, Patrick; Stein, Bernhard; Weidauer, Dirk; Wolf, Jean-Pierre; Woeste, Ludger H.; Fritzsche, Klaus

1993-09-01

Progresses in remote sensing of the atmosphere using the Udar (Light detection and ranging) technique closely follows progresses in Laser technology. We developed a mobile DIAL (differential absorption Lidar) system, based on high repetition rate Excimerpumped dye lasers, for performing 2D and 3D-mappings of concentration of NO, N02, S02, and 03. The high sensitivity of the system has been used for numerous environmental studies and measurement campaigns, providing for the first time a direct correlation between emission and immission. Attractive results have been obtained under urban conditions, because of the presence of strong concentration gradients, and fast fluctuations due to traffic. A comparative study between Lyon, Stuttgart, Geneva and Berlin will be presented. In particular, the Berlin-campaign demonstrates the possibility of detecting unknown emitters and monitoring exportation-importation processes of atmospheric pollution. A new stationary DIAL system has been recently constructed and implemented on the top of a building in the center of the city Leipzig. It will routinely perform concentration mappings of nitrogen oxides, sulfur dioxide and ozone, giving access to long term evolution of pollution distributions.

Bacteriophages as indicators of faecal pollution and enteric ...

EPA Pesticide Factsheets

Bacteriophages are an attractive alternative to fecal indicator bacteria (FIB), particularly as surrogates of enteric virus fate and transport due to their closer morphological and biological properties compared to FIB. Based on a meta-analysis of published data, we summarize concentrations of coliphages (F+ and somatic), Bacteroides spp. and enterococci bacteriophages (phages) in human waste, non-human waste, fresh and marine waters as well as removal through wastewater treatment processes. We also provide comparisons with FIB and enteric viruses whenever possible. Lastly, we examine fate and transport characteristics in the environment and provide an overview of the methods available for detection and enumeration of bacteriophages. In summary, concentrations of FIB bacteriophages in various sources were consistently lower than FIB, but more reflective of infectious enteric virus levels. Our investigation supports use of bacteriophages as viral surrogates especially for wastewater treatment processes, while additional research is needed to clarify their utility as indicators of viral fate and transport in the ambient water. Describes concentrations and removal through environmental and engineered systems of bacteriophages, fecal indicator bacteria and viral pathogens.

Anaerobic Digestion of Organic Fraction from Hydrothermal Liquefied Algae Wastewater Byproduct

DOE PAGES

Fernandez, Sebastian; Srinivas, Keerthi; Schmidt, Andrew J.; ...

2017-09-06

We present that the wastewater stream from hydrothermal liquefaction (HTL) process used in biofuel production, contains a large amounts of organic compounds where several can be regarded as environmentally hazardous and requires significant treatment before disposal. In this study, semi-continuous anaerobic digestion is used to degrade the organic fraction of wastewater streams from HTL of the algae Tetraselmis (AgTet) and Chlorella (AgChlr). Results indicated high methane yields at 20-30% (v/v) HTL wastewater together with clarified manure, producing 327.2 mL/gVS in (or volatile solids in feed) for AgTet and 263.4 mL/gVS in for AgChlr. There was a significant reduction in methanemore » production at concentrations higher than 40% (v/v) HTL wastewater in the feed, possibly due to the accumulation of chloride salts or inhibitory compounds such as pyridines, piperidines and pyrrolidines. In conclusion, this was further confirmed by comparing COD, salt and the ammonia concentrations of the effluents after anaerobic digestion at different concentrations of wastewater in manure.« less

Monitoring of trace element atmospheric deposition using dry and wet moss bags: accumulation capacity versus exposure time.

PubMed

Anicić, M; Tomasević, M; Tasić, M; Rajsić, S; Popović, A; Frontasyeva, M V; Lierhagen, S; Steinnes, E

2009-11-15

To clarify the peculiarities of trace element accumulation in moss bags technique (active biomonitoring), samples of the moss Sphagnum girgensohnii Rusow were exposed in bags with and without irrigation for 15 days up to 5 months consequently in the semi-urban area of Belgrade (Serbia) starting from July 2007. The accumulation capacity for 49 elements determined by ICP-MS in wet and dry moss bags was compared. The concentration of some elements, i.e. Al, V, Cr, Fe, Zn, As, Se, Sr, Pb, and Sm increased continuously with exposure time in both dry and wet moss bags, whereas concentration of Na, Cl, K, Mn, Rb, Cs, and Ta decreased. Irrigation of moss resulted in a higher accumulation capacity for most of the elements, especially for Cr, Zn, As, Se, Br, and Sr. Principal component analysis was performed on the datasets of element concentrations in wet and dry moss bags for source identification. Results of the factor analysis were similar but not identical in the two cases due to possible differences in element accumulation mechanisms.

Lead and cadmium concentrations in seawater and algae of the Tunisian coast.

PubMed

El Ati-Hellal, M; Hedhili, A; Hellal, F; Boujlel, K; Dachraoui, M; Bousnina, M; Ghorbel, H; Ndhif, M

2005-01-01

Both lead and cadmium are toxic trace metals, even in very weak concentrations. The aim of this study was to estimate lead and cadmium pollution in various sites of the Tunisian coast and to verify the possibility of modification of the algae bioconcentration power according to water physico-chemical conditions. Our study concerned 99 samples of algae and 99 samples of seawater, taken in different sites of the Tunisian littoral. The analysis was realized by atomic absorption spectrophotometry (oven graphite). In algae, Sfax site presented the highest concentrations of lead when Sousse site showed the lowest ones. In seawater, the most amounts of lead were observed in Bizerte, Mahdia and Sfax sites, and those of cadmium in Bizerte and Medenine coasts. Bizerte's coast seems to be the most exposed zone to pollution. Indeed, the intensification of sea traffic may take place on this pollution because hydrocarbons derived from petroleum contain some tetraethylic lead characterised by its great toxicity. Sousse's region is the least polluted zone; it might be due to the development of tourism and a strict regulation of pollution in this district.

Insights into controls on hexavalent chromium in groundwater provided by environmental tracers, Sacramento Valley, California, USA

USGS Publications Warehouse

Manning, Andrew H.; Mills, Christopher T.; Morrison, Jean M.; Ball, Lyndsay B.

2015-01-01

Environmental tracers are useful for determining groundwater age and recharge source, yet their application in studies of geogenic Cr(VI) in groundwater has been limited. Environmental tracer data from 166 wells located in the Sacramento Valley, northern California, were interpreted and compared to Cr concentrations to determine the origin and age of groundwater with elevated Cr(VI), and better understand where Cr(VI) becomes mobilized and how it evolves along flowpaths. In addition to major ion and trace element concentrations, the dataset includes δ18O, δ2H, 3H concentration, 14C activity (of dissolved inorganic C), δ13C, 3He/4He ratio, and noble gas concentrations (He, Ne, Ar, Kr, Xe). Noble gas recharge temperatures (NGTs) were computed, and age-related tracers were interpreted in combination to constrain the age distribution in samples and sort them into six different age categories spanning from <60 yr old to >10,000 yr old. Nearly all measured Cr is in the form of Cr(IV). Concentrations range from <1 to 46 μg L−1, with 10% exceeding the state of California’s Cr(VI) maximum contaminant level of 10 μg L−1. Two groups with elevated Cr(VI) (⩾5 μg L−1) were identified. Group 1 samples are from the southern part of the valley and contain modern (<60 yr old) water, have elevated NO3− concentrations (>3 mg L−1), and commonly have δ18O values enriched relative to local precipitation. These samples likely contain irrigation water and are elevated due to accelerated mobilization of Cr(VI) in the unsaturated zone (UZ) in irrigated areas. Group 2 samples are from throughout the valley and typically contain water 1000–10,000 yr old, have δ18O values consistent with local precipitation, and have unexpectedly warm NGTs. Chromium(VI) concentrations in Group 2 samples may be elevated for multiple reasons, but the hypothesis most consistent with all available data (notably, the warm NGTs) is a relatively long UZ residence time due to recharge through a deep UZ near the margin of the basin. A possible explanation for why Cr(VI) may be primarily mobilized in the UZ rather than farther along flowpaths in the oxic portion of the saturated zone is more dynamic cycling of Mn in the UZ due to transient moisture and redox conditions.

Gaps and rings carved by vortices in protoplanetary dust

NASA Astrophysics Data System (ADS)

Barge, Pierre; Ricci, Luca; Carilli, Christopher Luke; Previn-Ratnasingam, Rathish

2017-09-01

Context. Large-scale vortices in protoplanetary disks are thought to form and survive for long periods of time. Hence, they can significantly change the global disk evolution and particularly the distribution of the solid particles embedded in the gas, possibly explaining asymmetries and dust concentrations recently observed at submillimeter and millimeter wavelengths. Aims: We investigate the spatial distribution of dust grains using a simple model of protoplanetary disk hosted by a giant gaseous vortex. We explore the dependence of the results on grain size and deduce possible consequences and predictions for observations of the dust thermal emission at submillimeter and millimeter wavelengths. Methods: Global 2D simulations with a bi-fluid code are used to follow the evolution of a single population of solid particles aerodynamically coupled to the gas. Possible observational signatures of the dust thermal emission are obtained using simulators of ALMA and Nest Generation Very Large Array (ngVLA) observations. Results: We find that a giant vortex not only captures dust grains with Stokes number St< 1 but can also affect the distribution of larger grains (with St 1) carving a gap associated with a ring composed of incompletely trapped particles. The results are presented for different particle sizes and associated with their possible signatures in disk observations. Conclusions: Gap clearing in the dust spatial distribution could be due to the interaction with a giant gaseous vortex and their associated spiral waves without the gravitational assistance of a planet. Hence, strong dust concentrations at short sub-mm wavelengths associated with a gap and an irregular ring at longer mm and cm wavelengths could indicate the presence of an unseen gaseous vortex.

Spatial & temporal variations of PM10 and particle number concentrations in urban air.

PubMed

Johansson, Christer; Norman, Michael; Gidhagen, Lars

2007-04-01

The size of particles in urban air varies over four orders of magnitude (from 0.001 microm to 10 microm in diameter). In many cities only particle mass concentrations (PM10, i.e. particles <10 microm diameter) is measured. In this paper we analyze how differences in emissions, background concentrations and meteorology affect the temporal and spatial distribution of PM10 and total particle number concentrations (PNC) based on measurements and dispersion modeling in Stockholm, Sweden. PNC at densely trafficked kerbside locations are dominated by ultrafine particles (<0.1 microm diameter) due to vehicle exhaust emissions as verified by high correlation with NOx. But PNC contribute only marginally to PM10, due to the small size of exhaust particles. Instead wear of the road surface is an important factor for the highest PM10 concentrations observed. In Stockholm, road wear increases drastically due to the use of studded tires and traction sand on streets during winter; up to 90% of the locally emitted PM10 may be due to road abrasion. PM10 emissions and concentrations, but not PNC, at kerbside are controlled by road moisture. Annual mean urban background PM10 levels are relatively uniformly distributed over the city, due to the importance of long range transport. For PNC local sources often dominate the concentrations resulting in large temporal and spatial gradients in the concentrations. Despite these differences in the origin of PM10 and PNC, the spatial gradients of annual mean concentrations due to local sources are of equal magnitude due to the common source, namely traffic. Thus, people in different areas experiencing a factor of 2 different annual PM10 exposure due to local sources will also experience a factor of 2 different exposure in terms of PNC. This implies that health impact studies based solely on spatial differences in annual exposure to PM10 may not separate differences in health effects due to ultrafine and coarse particles. On the other hand, health effect assessments based on time series exposure analysis of PM10 and PNC, should be able to observe differences in health effects of ultrafine particles versus coarse particles.

Uptake of Silicon by Sugarcane from Applied Sources May Not Reflect Plant-Available Soil Silicon and Total Silicon Content of Sources.

PubMed

Keeping, Malcolm G

2017-01-01

Soils of the tropics and sub-tropics are typically acid and depleted of soluble sources of silicon (Si) due to weathering and leaching associated with high rainfall and temperatures. Together with intensive cropping, this leads to marginal or deficient plant Si levels in Si-accumulating crops such as rice and sugarcane. Although such deficiencies can be corrected with exogenous application of Si sources, there is controversy over the effectiveness of sources in relation to their total Si content, and their capacity to raise soil and plant Si concentrations. This study tested the hypothesis that the total Si content and provision of plant-available Si from six sources directly affects subsequent plant Si uptake as reflected in leaf Si concentration. Two trials with potted cane plants were established with the following Si sources as treatments: calcium silicate slag, fused magnesium (thermo) phosphate, volcanic rock dust, magnesium silicate, and granular potassium silicate. Silicon sources were applied at rates intended to achieve equivalent elemental soil Si concentrations; controls were untreated or lime-treated. Analyses were conducted to determine soil and leaf elemental concentrations. Among the sources, calcium silicate produced the highest leaf Si concentrations, yet lower plant-available soil Si concentrations than the thermophosphate. The latter, with slightly higher total Si than the slag, produced substantially greater increases in soil Si than all other products, yet did not significantly raise leaf Si above the controls. All other sources did not significantly increase soil or leaf Si concentrations, despite their high Si content. Hence, the total Si content of sources does not necessarily concur with a product's provision of soluble soil Si and subsequent plant uptake. Furthermore, even where soil pH was raised, plant uptake from thermophosphate was well below expectation, possibly due to its limited liming capacity. The ability of the calcium silicate to provide Si while simultaneously and significantly increasing soil pH, and thereby reducing reaction of Si with exchangeable Al 3+ , is proposed as a potential explanation for the greater Si uptake into the shoot from this source.

Uptake of Silicon by Sugarcane from Applied Sources May Not Reflect Plant-Available Soil Silicon and Total Silicon Content of Sources

PubMed Central

Keeping, Malcolm G.

2017-01-01

Soils of the tropics and sub-tropics are typically acid and depleted of soluble sources of silicon (Si) due to weathering and leaching associated with high rainfall and temperatures. Together with intensive cropping, this leads to marginal or deficient plant Si levels in Si-accumulating crops such as rice and sugarcane. Although such deficiencies can be corrected with exogenous application of Si sources, there is controversy over the effectiveness of sources in relation to their total Si content, and their capacity to raise soil and plant Si concentrations. This study tested the hypothesis that the total Si content and provision of plant-available Si from six sources directly affects subsequent plant Si uptake as reflected in leaf Si concentration. Two trials with potted cane plants were established with the following Si sources as treatments: calcium silicate slag, fused magnesium (thermo) phosphate, volcanic rock dust, magnesium silicate, and granular potassium silicate. Silicon sources were applied at rates intended to achieve equivalent elemental soil Si concentrations; controls were untreated or lime-treated. Analyses were conducted to determine soil and leaf elemental concentrations. Among the sources, calcium silicate produced the highest leaf Si concentrations, yet lower plant-available soil Si concentrations than the thermophosphate. The latter, with slightly higher total Si than the slag, produced substantially greater increases in soil Si than all other products, yet did not significantly raise leaf Si above the controls. All other sources did not significantly increase soil or leaf Si concentrations, despite their high Si content. Hence, the total Si content of sources does not necessarily concur with a product's provision of soluble soil Si and subsequent plant uptake. Furthermore, even where soil pH was raised, plant uptake from thermophosphate was well below expectation, possibly due to its limited liming capacity. The ability of the calcium silicate to provide Si while simultaneously and significantly increasing soil pH, and thereby reducing reaction of Si with exchangeable Al3+, is proposed as a potential explanation for the greater Si uptake into the shoot from this source. PMID:28555144

Photochemical modeling of emissions trading of highly reactive volatile organic compounds in Houston, Texas. 1. Reactivity based trading and potential for ozone hot spot formation.

PubMed

Wang, Linlin; Thompson, Tammy; McDonald-Buller, Elena C; Webb, Alba; Allen, David T

2007-04-01

As part of the State Implementation Plan for attaining the National Ambient Air Quality Standard for ozone, the Texas Commission of Environmental Quality has created a Highly Reactive Volatile Organic Compounds (HRVOC) Emissions Cap and Trade Program for industrial point sources in the Houston/Galveston/Brazoria area. This program has a number of unique features, including its focus on a limited group of ozone precursors and its provisions for trading emissions based on atmospheric reactivity. This series of papers examines the potential air quality impacts of this new emission trading program through photochemical modeling of potential trading scenarios; this first paper in the series describes the air quality modeling methods used to assess potential trades, the potential for localized increases in ozone concentrations (ozone "hot spots") due to HRVOC emission trading, and the use of reactivity scales in the trading. When HRVOC emissions are traded on a mass basis, the simulations indicate that trading of HRVOC allowances between facilities resulted in less than 0.15 ppb (<0.13%) and 0.06 ppb (<0.06%) increases in predicted maximum, area-wide 1-h averaged and 8-h averaged ozone concentrations, respectively. Maximum decreases in ozone concentrations associated with trading, as opposed to across-the-board reductions, were larger than the increases. All of these changes are small compared to the maximum changes in ozone concentrations due to the VOC emissions from these sources (up to 5-10 ppb for 8 h averages; up to 30 ppb for 1-h averages). When emissions of HRVOCs are traded for other, less reactive emissions, on a reactivity weighted basis, air quality simulations indicate that daily maximum ozone concentrations increased by less than 0.3%. Because these relatively small changes (< 1%) are for unlikely trading scenarios designed to produce a maximum change in ozone concentrations (all emissions traded into localized regions), the simulations indicate that the implementation of the trading program, as currently configured and possibly expanded, is unlikely to cause localized increases in ozone concentrations ("hot spots").

Seasonal prolactin secretion and its role in seasonal reproduction: a review.

PubMed

Curlewis, J D

1992-01-01

The majority of seasonally breeding mammals show a seasonal pattern of prolactin secretion with peak concentrations in spring or summer and a nadir in autumn or winter. Photoperiod influences prolactin secretion via its effects on the secretion of the pineal hormone melatonin. Preliminary evidence suggests that the effects of melatonin on both prolactin and gonadotrophin secretion are via a common target area, possibly within the anterior hypothalamus, and that differences in response to photoperiod may be due to differences in the processing and/or interpretation of the melatonin signal. In contrast to seasonal gonadotrophin secretion, the seasonal changes in prolactin are not due to changes in the sensitivity of a feedback loop and so must be due to direct effects on the hypothalamic pathways that control prolactin secretion. Little else can be said with confidence about the neuroendocrine mechanisms that lead to the seasonal changes in prolactin secretion. Dopamine and noradrenaline turnover in the arcuate nucleus and median eminence decrease under short daylength. If catecholamine turnover in these structures is positively correlated with catecholamine concentrations in the long or short hypophysial portal vessels, it is unlikely that the decrease in prolactin concentration in winter is due to the effects of increased concentrations of dopamine or noradrenaline in the portal vessels. There is, however, evidence for increased pituitary sensitivity to dopamine under short daylength, so increased dopamine concentrations may not be required for suppression of prolactin secretion at this time. In addition to the diminished secretion of prolactin under short daylength, rate of prolactin synthesis and pituitary content of prolactin also decline although the mechanisms that regulate these changes are poorly understood. Although all seasonal breeders show a seasonal change in prolactin secretion, there are continuously breeding species in which prolactin secretion is also under photoperiodic control. It is likely therefore that a seasonal pattern of prolactin secretion is only evidence of neuroendocrine sensitivity to changing photoperiod. Depending upon the species, this sensitivity to the seasonal changes in daylength may or may not be accompanied by seasonal changes in a biological endpoint such as seasonal reproduction or indeed other adaptations. Whether the seasonal change in prolactin secretion is an endocrine mediator of such adaptations remains in contention. Certainly in some species this signal does have a role in reproduction. For example, in species with an obligate seasonal embryonic diapause, the seasonal increase in prolactin can act as a luteotrophin (mink and western spotted skunk) or luteostatin (Bennett's and tammar wallabies.(ABSTRACT TRUNCATED AT 400 WORDS)

Quantitative Detection of Pharmaceuticals Using a Combination of Paper Microfluidics and Wavelength Modulated Raman Spectroscopy

PubMed Central

Craig, Derek; Mazilu, Michael; Dholakia, Kishan

2015-01-01

Raman spectroscopy has proven to be an indispensable technique for the identification of various types of analytes due to the fingerprint vibration spectrum obtained. Paper microfluidics has also emerged as a low cost, easy to fabricate and portable approach for point of care testing. However, due to inherent background fluorescence, combining Raman spectroscopy with paper microfluidics is to date an unmet challenge in the absence of using surface enhanced mechanisms. We describe the first use of wavelength modulated Raman spectroscopy (WMRS) for analysis on a paper microfluidics platform. This study demonstrates the ability to suppress the background fluorescence of the paper using WMRS and the subsequent implementation of this technique for pharmaceutical analysis. The results of this study demonstrate that it is possible to discriminate between both paracetamol and ibuprofen, whilst, also being able to detect the presence of each analyte quantitatively at nanomolar concentrations. PMID:25938464

Biocompatibility and biodistribution of functionalized carbon nano-onions (f-CNOs) in a vertebrate model

NASA Astrophysics Data System (ADS)

D' Amora, Marta; Rodio, Marina; Bartelmess, Juergen; Sancataldo, Giuseppe; Brescia, Rosaria; Cella Zanacchi, Francesca; Diaspro, Alberto; Giordani, Silvia

2016-09-01

Functionalized carbon nano-onions (f-CNOs) are of great interest as platforms for imaging, diagnostic and therapeutic applications due to their high cellular uptake and low cytotoxicity. To date, the toxicological effects of f-CNOs on vertebrates have not been reported. In this study, the possible biological impact of f-CNOs on zebrafish during development is investigated, evaluating different toxicity end-points such as the survival rate, hatching rate, and heart beat rate. Furthermore, a bio-distribution study of boron dipyrromethene (BODIPY) functionalized CNOs in zebrafish larvae is performed by utilizing inverted selective plane illumination microscopy (iSPIM), due to its intrinsic capability of allowing for fast 3D imaging. Our in vivo findings indicate that f-CNOs exhibit no toxicity, good biocompatibility (in the concentration range of 5-100 μg mL-1) and a homogenous biodistribution in zebrafish larvae.

Modeling the Risk of Fire/Explosion Due to Oxidizer/Fuel Leaks in the Ares I Interstage

NASA Technical Reports Server (NTRS)

Ring, Robert W.; Stott, James E.; Hales, Christy

2008-01-01

A significant flight hazard associated with liquid propellants, such as those used in the upper stage of NASA's new Ares I launch vehicle, is the possibility of leakage of hazardous fluids resulting in a catastrophic fire/explosion. The enclosed and vented interstage of the Ares I contains numerous oxidizer and fuel supply lines as well as ignition sources. The potential for fire/explosion due to leaks during ascent depends on the relative concentrations of hazardous and inert fluids within the interstage along with other variables such as pressure, temperature, leak rates, and fluid outgasing rates. This analysis improves on previous NASA Probabilistic Risk Assessment (PRA) estimates of the probability of deflagration, in which many of the variables pertinent to the problem were not explicitly modeled as a function of time. This paper presents the modeling methodology developed to analyze these risks.

Factors affecting the stability of drug-loaded polymeric micelles and strategies for improvement

NASA Astrophysics Data System (ADS)

Zhou, Weisai; Li, Caibin; Wang, Zhiyu; Zhang, Wenli; Liu, Jianping

2016-09-01

Polymeric micelles (PMs) self-assembled by amphiphilic block copolymers have been used as promising nanocarriers for tumor-targeted delivery due to their favorable properties, such as excellent biocompatibility, prolonged circulation time, favorable particle sizes (10-100 nm) to utilize enhanced permeability and retention effect and the possibility for functionalization. However, PMs can be easily destroyed due to dilution of body fluid and the absorption of proteins in system circulation, which may induce drug leakage from these micelles before reaching the target sites and compromise the therapeutic effect. This paper reviewed the factors that influence stability of micelles in terms of thermodynamics and kinetics consist of the critical micelle concentration of block copolymers, glass transition temperature of hydrophobic segments and polymer-polymer and polymer-cargo interaction. In addition, some effective strategies to improve the stability of micelles were also summarized.

Improved limits and portability over currently employed cadmium monitoring systems through preconcentration for detection by way of micro-/nanofluidic mechanisms

NASA Astrophysics Data System (ADS)

Wach, Paul

Due to risk of environmental and biological accumulation of Cadmium (Cd), improved methods of early detection and monitoring must be explored as a preventative measure. Listed as one of the top three toxic heavy metals by the Environmental Protection Agency (EPA), the effects on ecological and human systems have well documented side-effects of physical mutation, reproductive sterility, kidney failure, liver disease, bone loss, and death. Found in batteries, metal plating, pigments, plastics, and cigarettes, Cd is also used as a neutron absorber in the nuclear industry as well as having 3 known radioactive isotopes. Urine Cd levels, which have been widely used to predict whole body levels, increase when kidney damage occurs, thus increasing the importance to monitor and detect as early as possible. Although several methods of detection and monitoring are currently in use, they are insufficient for reasons including massive expense, weak specificity causing false readings, and/or a lack of portability. By exploiting naturally occurring mechanisms known to micro-/nanofluidics, a novel approach to Cd detection, measurement, and preconcentration was explored using the finite element computational software COMSOL. An open flow system of a nanochannel was explored through manipulation of the surface charge density. With a dominant negatively charged density on the walls, positive surface charge densities were adjacently placed at the center of the nanochannel causing a constriction of flow and allowing preconcentration of the analytes. When the open flow system was scaled up to a microchannel, the mechanism was found to have little effect on constriction of the flow. A preconcentration effect was discovered in a closed flow system when the adjacent patches were modeled as being impermeable to charge, causing the molecules to migrate to and remain at the central region of the microchannel once the dynamic process reached steady state. It was found to have the ability to concentrate Cd at an initial concentration of 0.5 mol/m3, which is nearly half the limit of commercially available technology. Additionally, this preconcentration mechanism was demonstrated to potentially advance its capabilities by attaching channels in series or parallel to further preconcentrate for improved detection. Finally, measurement of extremely low concentrations of Cd is possible due to differences seen in the concentration distribution profiles once steady-state is reached.

Nitrate source indicators in ground water of the Scimitar Subdivision, Peters Creek area, Anchorage, Alaska

USGS Publications Warehouse

Wang, Bronwen; Strelakos, Pat M.; Jokela, Brett

2000-01-01

A combination of aqueous chemistry, isotopic measurement, and in situ tracers were used to study the possible nitrate sources, the factors contributing to the spatial distribution of nitrate, and possible septic system influence in the ground water in the Scimitar Subdivision, Municipality of Anchorage, Alaska. Two water types were distinguished on the basis of the major ion chemistry: (1) a calcium sodium carbonate water, which was associated with isotopically heavier boron and with chlorofluorocarbons (CFC's) that were in the range expected from equilibration with the atmosphere (group A water) and (2) a calcium magnesium carbonate water, which was associated with elevated nitrate, chloride, and magnesium concentrations, generally isotopically lighter boron, and CFC's concentrations that were generally in excess of that expected from equilibration with the atmosphere (group B water). Water from wells in group B had nitrate concentrations that were greater than 3 milligrams per liter, whereas those in group A had nitrate concentrations of 0.2 milligram per liter or less. Nitrate does not appear to be undergoing extensive transformation in the ground-water system and behaves as a conservative ion. The major ion chemistry trends and the presence of CFC's in excess of an atmospheric source for group B wells are consistent with waste-water influences. The spatial distribution of the nitrate among wells is likely due to the magnitude of this influence on any given well. Using an expanded data set composed of 16 wells sampled only for nitrate concentration, a significant difference in the static water level relative to bedrock was found. Well water samples with less than 1 milligram per liter nitrate had static water levels within the bedrock, whereas those samples with greater than 1 milligram per liter nitrate had static water levels near or above the top of the bedrock. This observation would be consistent with a conceptual model of a low-nitrate fractured bedrock aquifer that receives slow recharge from an overlying nitrate-enriched surficial aquifer.

Development of acute exposure guideline levels for airborne exposures to hazardous substances.

PubMed

Krewski, Daniel; Bakshi, Kulbir; Garrett, Roger; Falke, Ernest; Rusch, George; Gaylor, David

2004-04-01

Hazardous substances can be released into the atmosphere due to industrial and transportation accidents, fires, tornadoes, earthquakes, and terrorists, thereby exposing workers and the nearby public to potential adverse health effects. Various enforceable guidelines have been set by regulatory agencies for worker and ambient air quality. However, these exposure levels generally are not applicable to rare lifetime acute exposures, which possibly could occur at high concentrations. Acute exposure guideline levels (AEGLs) provide estimates of concentrations for airborne exposures for an array of short durations that possibly could cause mild (AEGL-1), severe, irreversible, potentially disabling adverse health effects (AEGL-2), or life threatening effects (AEGL-3). These levels can be useful for emergency responders and planners in reducing or eliminating potential risks to the public. Procedures and methodologies for deriving AEGLs are reviewed in this paper that have been developed in the United States, with direct input from international representatives of OECD member-countries, by the National Advisory Committee for Acute Exposure Guidelines for Hazardous Substances and reviewed by the National Research Council. Techniques are discussed for the extrapolation of effects across different exposure durations. AEGLs provide a viable approach for assisting in the prevention, planning, and response to acute airborne exposures to toxic agents.

A rapid, highly sensitive and culture-free detection of pathogens from blood by positive enrichment.

PubMed

Vutukuru, Manjula Ramya; Sharma, Divya Khandige; Ragavendar, M S; Schmolke, Susanne; Huang, Yiwei; Gumbrecht, Walter; Mitra, Nivedita

2016-12-01

Molecular diagnostics is a promising alternative to culture based methods for the detection of bloodstream infections, notably due to its overall lower turnaround time when starting directly from patient samples. Whole blood is usually the starting diagnostic sample in suspected bloodstream infections. The detection of low concentrations of pathogens in blood using a molecular assay necessitates a fairly high starting volume of blood sample in the range of 5-10mL. This large volume of blood sample has a substantial accompanying human genomic content that interferes with pathogen detection. In this study, we have established a workflow using magnetic beads coated with Apolipoprotein H that makes it possible to concentrate pathogens from a 5.0mL whole blood sample, thereby enriching pathogens from whole blood background and also reducing the sample volume to ~200μL or less. We have also demonstrated that this method of enrichment allows detection of 1CFU/mL of Escherichia coli, Enterococcus gallinarum and Candida tropicalis from 5mL blood using quantitative PCR; a detection limit that is not possible in unenriched samples. The enrichment method demonstrated here took 30min to complete and can be easily integrated with various downstream molecular and microbiological techniques. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification and quantification of pesticide residues in water samples of Dhamrai Upazila, Bangladesh

NASA Astrophysics Data System (ADS)

Hasanuzzaman, M.; Rahman, M. A.; Salam, M. A.

2017-10-01

Being agricultural country, different types of pesticides are widely used in Bangladesh to prevent the crop losses due to pest attack which are ultimately drain to the water bodies. The present study was conducted to identify and quantify the organochlorine (DDT, DDE and DDD), organophosphorus (malathion, diazinon and chloropyrifos) and carbamate (carbaryl) residues in water samples of different sources from Dhamrai upazila of Bangladesh using high performance liquid chromatography (HPLC) equipped with ultra violate (UV) detector. Thirty water samples from fish pond, cultivated land and tube-well were collected in winter season to analyze the pesticide residues. Among the organophosphorus pesticides, malathion was present in seven water samples ranging from 42.58 to 922.8 μg/L, whereas diazinon was detected in water sample-8 (WS-8) and the concentration was 31.5 μg/L. None of the tested water samples was found to be contaminated with chlorpyrifos, carbaryl or DDT and its metabolites (DDE and DDD). Except for a tube-well water sample, concentrations of the detected residues are above the acceptable limit for human body as assigned by different organizations. To avoid the possible health hazards, the indiscriminate application of pesticides should be restricted and various substitute products like bio-pesticide should be introduced in a broad scale as soon as possible.

Nitrogen metabolism of sheep and goats consuming Acacia brevispica and Sesbania sesban

USGS Publications Warehouse

Woodward, A.; Reed, J.D.

1997-01-01

We described the effects of two East African browses, Acacia brevispica and Sesbania sesban, on nitrogen metabolism of sheep and goats. The A. brevispica had a substantial amount of proanthocyanidins (condensed tannins); S. sesban did not. The browses were fed at three levels in combination with vetch (Vicia dasycarpa) and teff straw (Eragrostis abyssinica). Fecal N, N balance, and plasma urea N (PUN) were estimated with intact animals. Ruminal ammonia (RuA) and VFA concentrations were estimated with ruminally fistulated animals. Urinary N loss, PUN, RuA, and VFA concentrations were higher for S. sesban diets than for A. brevispica diets. Fecal N was highest with diets including A. brevispica due to high levels of fecal neutral-detergent insoluble N. Nitrogen retention was highest for diets including S. sesban. Nitrogen retention was adequate for A. brevispica diets because low urinary N compensated for high fecal N. Four hypotheses describe possible effects of tannins on N metabolism: 1) escape of protein from the rumen to the lower tract; 2) increased microbial yield; 3) increase in N-containing endogenous products; and 4) protein made indigestible in tannin-protein complexes. The effect of tannins in A. brevispica on N metabolism can best be described by the formation of indigestible tannin-protein complexes, although increased production of endogenous products is also possible.

Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning

NASA Technical Reports Server (NTRS)

Hameed, S.; Cess, R. D.; Hogan, J. S.

1980-01-01

Recent modeling of atmospheric chemical processes (Logan et al, 1978; Hameed et al, 1979) suggests that tropospheric ozone and methane might significantly increase in the future as the result of increasing anthropogenic emissions of CO, NO(x), and CH4 due to fossil fuel burning. Since O3 and CH4 are both greenhouse gases, increases in their concentrations could augment global warming due to larger future amounts of atmospheric CO2. To test the possible climatic impact of changes in tropospheric chemical composition, a zonal energy-balance climate model has been combined with a vertically averaged tropospheric chemical model. The latter model includes all relevant chemical reactions which affect species derived from H2O, O2, CH4, and NO(x). The climate model correspondingly incorporates changes in the infrared heating of the surface-troposphere system resulting from chemically induced changes in tropospheric ozone and methane. This coupled climate-chemical model indicates that global climate is sensitive to changes in emissions of CO, NO(x) and CH4, and that future increases in these emissions could augment global warming due to increasing atmospheric CO2.

Metals accumulations during thermal processing of sewage sludge - characterization of bottom ash and air pollution control (APC) residues

NASA Astrophysics Data System (ADS)

Kasina, Monika; Kowalski, Piotr R.; Michalik, Marek

2016-04-01

Due to increasing mass of sewage sludge, problems in its management have appeared. Over years sewage sludge was landfilled, however due to EU directives concerning environmental issues this option is no longer possible. This type of material is considered hazardous due to highly concentrated metals and harmful elements, toxic organic substances and biological components (e.g. parasites, microbes). Currently in Europe, incineration is considered to be the most reasonable method for sewage sludge treatment. As a result of sludge incineration significant amount of energy is recovered due to high calorific value of sewage sludge but bottom ash and APC residues are being produced. In this study we show the preliminary results of chemical and mineral analyses of both bottom ash and APC residues produced in fluidized bed boiler in sewage sludge incineration plant in Poland, with a special emphasis on metals which, as a part of incombustible fraction can accumulate in the residual materials after thermal processing. The bottom ash was a SiO2-P2O5-Fe2O3-CaO-Al2O3 dominated material. Main mineral phases identified in X-ray diffraction patterns were: quartz, feldspar, hematite, and phosphates (apatite and scholzite). The bottom ash was characterized by high content of Zn - 4472 mg kg-1, Cu - 665.5 mg kg-1, Pb - 138 mg kg-1, Ni - 119.5 mg kg-1, and interestingly high content of Au - 0.858 mg kg-1 The APC residues composition was dominated by soluble phases which represent more than 90% of the material. The XRD patterns indicated thenardite, halite, anhydrite, calcite and apatite as main mineral phases. The removal of soluble phases by dissolution in deionised water caused a significant mass reduction (ca. 3% of material remained on the filters). Calcite, apatite and quartz were main identified phases. The content of metals in insoluble material is relatively high: Zn - 6326 mg kg-1, Pb - 514.3 mg kg-1, Cu - 476.6 mg kg-1, Ni - 43.3 mg kg-1. The content of Cd, As, Se and Hg was noted also what can be a reason of potential environmental concerns. A significant reduction of sludge volume after incineration causes concentration of numerous elements in both types of residues. The removal of soluble fraction from APC residues caused almost a 30-fold additional concentration of elements what makes this material interesting in terms of metals recovery. A detailed identification of metals occurrences and their distribution within mineral phases will be of a great importance in determination of possibilities of their recovery. Acknowledgment: The study was supported by Polish Nacional Science Centre NCN grant No UMO-2014/15/B/ST10/04171

Numerical modelling and experimental analysis of acoustic emission

NASA Astrophysics Data System (ADS)

Gerasimov, S. I.; Sych, T. V.

2018-05-01

In the present paper, the authors report on the application of non-destructive acoustic waves technologies to determine the structural integrity of engineering components. In particular, a finite element (FE) system COSMOS/M is used to investigate propagation characteristics of ultrasonic waves in linear, plane and three-dimensional structures without and with geometric concentrators. In addition, the FE results obtained are compared to the analytical and experimental ones. The study illustrates the efficient use of the FE method to model guided wave propagation problems and demonstrates the FE method’s potential to solve problems when an analytical solution is not possible due to “complicated” geometry.

Cryopreservation of red blood cells.

PubMed

Lagerberg, Johan W

2015-01-01

Cryopreservation of red blood cell concentrates (RBCs) is an important method for maintaining an inventory of rare RBC units and managing special transfusion circumstances. The permeating additive glycerol is used as a cryoprotectant to protect RBCs against freezing damage. The use of thawed RBCs was hampered a 24-h outdating period due to potential bacterial contamination when a functionally open system was used for addition and removal of the glycerol. With the introduction of a functionally closed system for the glycerolization and deglycerolization of RBC units, extended post-thaw storage became possible. Here, we describe the cryopreservation of red blood cells according to the high-glycerol method, using a functionally closed processing system.

A search for formic acid in the upper troposphere - A tentative identification of the 1105-per cm nu-6 band Q branch in high-resolution balloon-borne solar absorption spectra

NASA Technical Reports Server (NTRS)

Goldman, A.; Murcray, F. H.; Murcray, D. G.; Rinsland, C. P.

1984-01-01

Infrared solar absorption spectra recorded at 0.02-per cm resolution during a balloon flight from Alamogordo, NM (33 deg N), on March 23, 1981, have been analyzed for the possible presence of absorption by formic acid (HCOOH). An absorption feature at 1105 per cm has been tentatively identified in upper tropospheric spectra as due to the nu-6 band Q branch. A preliminary analysis indicates a concentration of about 0.6 ppbv and 0.4 ppbv near 8 and 10 km, respectively.

Optimal reconstruction angles

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

Cook, G.O. Jr.; Knight, L.

1979-07-01

The question of optimal projection angles has recently become of interest in the field of reconstruction from projections. Here, studies are concentrated on the n x n pixel space, where literative algorithms such as ART and direct matrix techniques due to Katz are considered. The best angles are determined in a Gauss--Markov statistical sense as well as with respect to a function-theoretical error bound. The possibility of making photon intensity a function of angle is also examined. Finally, the best angles to use in an ART-like algorithm are studied. A certain set of unequally spaced angles was found to bemore » preferred in several contexts. 15 figures, 6 tables.« less

Fluvial biofilms exposed to desiccation and pharmaceutical pollution: New insights using metabolomics.

PubMed

Serra-Compte, Albert; Corcoll, Natàlia; Huerta, Belinda; Rodríguez-Mozaz, Sara; Sabater, Sergi; Barceló, Damià; Álvarez-Muñoz, Diana

2018-03-15

In many arid and semi-arid systems, biological communities in river ecosystems are submitted to flow interruption and desiccation, as well as to the impact of urban wastewaters. In this work, we studied (using a LC-LTQ-Orbitrap) the metabolomic response of biofilm communities exposed to both hydrological and chemical stressors. Fluvial biofilms were exposed to a mixture of 9 pharmaceuticals at a total concentration of 5000ng/L (mimicking concentrations and compounds found in polluted aquatic environments) and/or to seven days of desiccation, under laboratory conditions. The biosynthesis of fatty acids was the main metabolic pathway disrupted in biofilms. Endogenous biofilm's metabolites (metabolome) altered due to these stressors were identified. The metabolites that significantly changed only due to one of the stressors could be proposed as potential specific biomarkers. A biomarker of pharmaceutical exposure was the lysophosphatidic acid, which decreased a 160%, while for desiccation stearidonic acid (increased 160%), 16-Oxohexadecanoic acid (increased 340%) and palmitoleic acid (decreased 290%) were the biomarkers proposed. Besides, other metabolites showed different responses depending on the treatment, such as palmitic acid, linolenic acid, behenic acid, lignoceric acid and azelaic acid. The Carbon:Phosphorus (C:P) molar ratio increased due to all stress factors, whereas the algal community composition changed mainly due to desiccation. A possible relationship between those changes observed in structural parameters and the metabolome of biofilms was explored. Overall, our findings support the use of metabolomics to unravel at molecular level the effects from chemical and physical stressors on complex microbial communities, such as biofilms, and pinpoint biomarkers of exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

Heavy metals in the volcanic environment and thyroid cancer.

PubMed

Vigneri, R; Malandrino, P; Gianì, F; Russo, M; Vigneri, P

2017-12-05

In the last two decades thyroid cancer incidence has increased worldwide more than any other cancer. Overdiagnosis of subclinical microcarcinomas has certainly contributed to this increase but many evidences indicate that a true increase, possibly due to environmental factors, has also occurred. Thyroid cancer incidence is markedly increased in volcanic areas. Thus, the volcanic environment is a good model to investigate the possible factors favoring thyroid cancer. In the volcanic area of Mt. Etna in Sicily, as well as in other volcanic areas, a non-anthropogenic pollution with heavy metals has been documented, a consequence of gas, ash and lava emission. Soil, water and atmosphere contamination, via the food chain, biocontaminate the residents as documented by high levels in the urines and the scalp hair compared to individuals living in adjacent non-volcanic areas. Trace amounts of metals are essential nutrients but, at higher concentrations, can be toxic for living cells. Metals can behave both as endocrine disruptors, perturbing the hormonal system, and as carcinogens, promoting malignant transformation. Similarly to other carcinogens, the transforming effect of heavy metals is higher in developing organisms as the fetus (contaminated via the mother) and individuals in early childhood. In the last decades environment metal pollution has greatly increased in industrialized countries. Although still within the "normal" limits for each single metal the hormesis effect (heavy metal activity at very low concentration because of biphasic, non linear cell response) and the possible potentiation effect resulting from the mixture of different metals acting synergistically can explain cell damage at very low concentrations. The effect of metals on the human thyroid is poorly studied: for some heavy metals no data are available. The scarce studies that have been performed mainly focus on metal effect as thyroid endocrine disruptors. The metal concentration in tissues has been rarely measured in the thyroid. Heavy metal accumulation and metabolism in the thyroid or the carcinogenic activity of different doses and different speciation of metals has not been investigated. These studies are now warranted to better understand thyroid biology and heavy metal role in human thyroid carcinogenesis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

[Assessment of occupational exposure to wood dust in the Polish furniture industry].

PubMed

Szewczyńska, Małgorzata; Pośniak, Małgorzata

2017-02-28

Occupational exposure to wood dust can be responsible for many different harmful health effects, especially in workers employed in the wood industry. The assessment of wood dust adverse effects to humans, as well as the interpretation of its concentration measurements carried out to assess potential occupational exposure are very difficult. First of all, it is due to possible occurrence of different kind of wood dust in the workplace air, namely wood dust from dozens of species of trees belonging to 2 kinds of botanical gymnosperms and angiosperms, as well as to its different chemical composition. Total dust and respirable wood dust in the workplace air in the furniture industry was determined using the filtration-gravimetric method in accordance with Polish Standards PN-Z-04030-05:1991 and PN-Z-04030-06:1991. Air samples were collected based on the principles of individual dosimetry. Total dust concentrations were 0.84-13.92 mg/m³ and inhalable fraction concentrations, obtained after the conversion of total dust by applying a conversion factor of 1.59, were 1.34-22.13 mg/m³. Respirable fraction concentrations were 0.38-4.04 mg/m³, which makes approx. 25% of the inhalable fraction on average. The highest concentrations occurred in grinding and the lowest during milling processes of materials used in the manufacture of furniture. The results indicate that the share of respirable fraction in the inhalable fraction of wood dust is considerable. Due to the determination of the threshold limit value (TLV) for the inhalable fraction of wood dust, it is necessary to replace the previously used samplers for total dust with samplers that provide quantitative separation of wood dust inhalable fractions in accordance with the convention of this fraction as defined in PN-EN 481:1998. Med Pr 2017;68(1):45-60. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Combined use of the entomopathogenic fungus, Metarhizium brunneum, and the mosquito predator, Toxorhynchites brevipalpis, for control of mosquito larvae: Is this a risky biocontrol strategy?

PubMed

Alkhaibari, Abeer M; Maffeis, Thierry; Bull, James C; Butt, Tariq M

2018-03-01

Mosquitoes transmit several diseases, which are of global significance (malaria, dengue, yellow fever, Zika). The geographic range of mosquitoes is increasing due to climate change, tourism and trade. Both conidial and blastospore formulations of the entomopathogenic fungus, Metarhizium brunneum ARSEF 4556, are being investigated as mosquito larvicides. However, concerns have been raised over possible non-target impacts to arthropod mosquito predators such as larvae of Toxorhynchites brevipalpis which feed on larvae of mosquito vector species. Laboratory-based, small container bioassays showed, that T. bevipalpis larvae are susceptible to relatively high concentrations (i.e. ≥10 7  spores ml -1 ) of inoculum with blastospores being significantly more virulent than conidia. At lower concentrations (e.g. <10 7  spores ml -1 ), it appears that M. brunneum complements T. brevipalpis resulting in higher control than if either agent was used alone. At a concentration of 10 5  spores ml -1 , the LT 50 of for conidia and blastospores alone was 5.64 days (95% CI: 4.79-6.49 days) and 3.89 days (95% CI: 3.53-4.25 days), respectively. In combination with T. brevipalpis, this was reduced to 3.15 days (95% CI: 2.82-3.48 days) and 2.82 days (95% CI: 2.55-3.08 days). Here, combined treatment with the fungus and predator was beneficial but weaker than additive. At 10 7 and 10 8  blastospores ml -1 , mosquito larval mortality was mostly due to the fungal pathogen when the predator was combined with blastospores. However, with conidia, the effects of combined treatment were additive/synergistic at these high concentrations. Optimisation of fungal concentration and formulation will reduce: (1) risk to the predator and (2) application rates and costs of M. brunneum for control of mosquito larvae. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Enhancement of tritium concentrations on uptake by marine biota: experience from UK coastal waters.

PubMed

Hunt, G J; Bailey, T A; Jenkinson, S B; Leonard, K S

2010-03-01

Concentrations of tritium in sea water and marine biota as reported over the last approximately 10 years from monitoring programmes carried out by this laboratory under contract to the UK Food Standards Agency are reviewed from three areas: near Cardiff; Sellafield; and Hartlepool. Near Cardiff, enhancement of concentration factors (CFs) above an a priori value of approximately 1 have already been studied, and attributed to compounds containing organically bound tritium in local radioactive waste discharges. Further data for Cardiff up to 2006 are reported in this note. Up to 2001, CFs increased to values of more than approximately 7000 in flounders and approximately 4000 in mussels, but have subsequently reduced; this variability could be due to changes in the organic constitution of compounds discharged. Near Sellafield and Hartlepool, enhancements to the tritium concentration factor are observed but they are relatively small compared with those near Cardiff. Near Sellafield, plaice and mussels appear to have a CF for tritium of approximately 10; in some cases concentrations of tritium in winkles are below detection limits and positively measured values indicate a CF of approximately 3. The variation could be due to mechanisms of uptake by the different organisms. Near Hartlepool there were only a few cases where tritium was positively measured. These data give a value of approximately 5 for the CF in plaice (on the basis of two samples); approximately 15 in winkles (eight samples); and > 45 in mussels (two samples). Any differences between the behaviours at Sellafield and Hartlepool would need to be confirmed by improved measurements. Possible causes are the organic composition of the effluent and differences in environmental behaviour and uptake by organisms near the two sites. These potential causes need further investigation. It is emphasised that results from tritium analyses are heavily method dependent; thus comparison with results from other programmes needs to take this into account. Further, the results for enhancement of CF will also depend on the definition of CF itself.

Wood ash residue causes a mixture of growth promotion and toxicity in Lemna minor.

PubMed

Jagodzinski, Lucas S; O'Donoghue, Marian T; Heffernan, Liam B; van Pelt, Frank N A M; O'Halloran, John; Jansen, Marcel A K

2018-06-01

The use of wood as a sustainable biofuel results in the generation of residual wood ash. The ash contains high amounts of plant macronutrients such as phosphorus, potassium, calcium as well as several micronutrients. To explore the potential use of wood ash as a fertiliser, the growth enhancing properties of Sitka spruce (Picea sitchensis Bong.) wood ash were contrasted with the potential toxic action, using common duckweed (Lemna minor L.) as a model test species. The growth of L. minor exposed to wood bottom and fly ash solids and corresponding leachates was assessed in ultra-oligotrophic and eutrophic media. Ash solids and leachates were also tested as neutralized preparations. Suspended ash solids promoted L. minor growth up to concentrations of 2.5-5g/L. Leachates promoted growth up to 10g ash equivalents per litre, but for bottom ash only. Beneficial effects of wood ash were most pronounced on ultra-oligotrophic medium. However, on such nutrient-deficient medium severe inhibition of L. minor biomass and frond growth was observed at relatively low concentrations of fly ash (EC 50 =14g/L). On standard, eutrophic medium, higher concentrations of fly ash (EC 50 =21g/L), or neutralized fly ash (EC 50 =37g/L) were required to impede growth. Bottom ash, or neutralized bottom ash retarded growth at concentrations of 51g/L and 74g/L (EC 50 ), respectively, in eutrophic medium. It appears that phytotoxicity is due to the elemental composition of the ash, its alkaline character, and possible interactions between these two properties. Growth promotion was due to the substantial content of plant nutrients. This study underlines the importance of the receiving environment (nutrient status and pH) in determining the balance between toxicity and growth promotion, and shows that the margin between growth promoting and toxicity inducing concentrations can be enlarged through ash neutralization. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of inert dust on olive (Olea europaea L.) leaf physiological para.

PubMed

Nanos, George D; Ilias, Ilias F

2007-05-01

Cement factories are major pollutants for the surrounding areas. Inert dust deposition has been found to affect photosynthesis, stomatal functioning and productivity. Very few studies have been conducted on the effects of cement kiln dust on the physiology of perennial fruit crops. Our goal was to study some cement dust effects on olive leaf physiology.effects on olive leaf physiology. On Cement kiln dust has been applied periodically since April 2003 onto olive leaves. Cement dust accumulation and various leaf physiological parameters were evaluated early in July 2003. Measurements were also taken on olive trees close to the cement factory. Leaf dry matter content and specific leaf weight increased with leaf age and dust content. Cement dust decreased leaf total chlorophyll content and chlorophyll a/chlorophyll b ratio. As a result, photosynthetic rate and quantum yield decreased. In addition, transpiration rate slightly decreased, stomatal conductance to H2O and CO2 movement decreased, internal CO2 concentration remained constant and leaf temperature increased. The changes in chlorophyll are possibly due to shading and/or photosystem damage. The changes in stomatal functioning were possibly due to dust accumulation between the peltates or othe effects on stomata. Dust (in this case from a cement kiln) seems to cause substantial changes to leaf physiology, possibly leading to reduced olive productivity. Avoidance of air contamination from cement factories by using available technology should be examined together with any possible methodologies to reduce plant tissue contamination from cement dust. Longterm effects of dust (from cement kiln or other sources) on olive leaf, plant productivity and nutritional quality of edible parts could be studied for conclusive results on dust contamination effects to perennial crops.

Quantitative correlation between the void morphology of niobium-tin wires and their irreversible critical current degradation upon mechanical loading

DOE PAGES

Barth, Christian; Seeber, B.; Rack, A.; ...

2018-04-26

Understanding the critical current performance variation of Nb 3Sn superconducting wires under mechanical loading is a crucial issue for the design of next generation accelerator and fusion magnets. In these applications, the mechanical properties of the conductors may become a limiting factor due to the strong electro-magnetic forces resulting from the combination of large magnets and intense magnetic fields. In particular, the presence of voids in the superconducting filament structure, which are formed during the fabrication and the reaction heat treatment, determines localized stress concentrations and possibly the formation of cracks. In this work, we demonstrate a quantitative correlation betweenmore » the void morphology and the electro-mechanical limits measured on different Bronze route Nb 3Sn wires. Hot Isostatic Pressing (HIP) prior to the reaction heat treatment is utilized to partially eliminate the voids. The wires’ void distributions - with and without HIP treatment - are detected and statistically analyzed using high energy X-ray micro tomography. The stress concentration due to the shape and distribution of the voids as well as their impact on the electro-mechanical properties are determined through finite element method modeling. Lastly, the results are quantitatively correlated with the experimentally determined limits of the irreversible critical current degradation upon mechanical loading.« less

Quantitative correlation between the void morphology of niobium-tin wires and their irreversible critical current degradation upon mechanical loading

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

Barth, Christian; Seeber, B.; Rack, A.

Understanding the critical current performance variation of Nb 3Sn superconducting wires under mechanical loading is a crucial issue for the design of next generation accelerator and fusion magnets. In these applications, the mechanical properties of the conductors may become a limiting factor due to the strong electro-magnetic forces resulting from the combination of large magnets and intense magnetic fields. In particular, the presence of voids in the superconducting filament structure, which are formed during the fabrication and the reaction heat treatment, determines localized stress concentrations and possibly the formation of cracks. In this work, we demonstrate a quantitative correlation betweenmore » the void morphology and the electro-mechanical limits measured on different Bronze route Nb 3Sn wires. Hot Isostatic Pressing (HIP) prior to the reaction heat treatment is utilized to partially eliminate the voids. The wires’ void distributions - with and without HIP treatment - are detected and statistically analyzed using high energy X-ray micro tomography. The stress concentration due to the shape and distribution of the voids as well as their impact on the electro-mechanical properties are determined through finite element method modeling. Lastly, the results are quantitatively correlated with the experimentally determined limits of the irreversible critical current degradation upon mechanical loading.« less

Singlet Oxygen Generation by UVA Light Exposure of Endogenous Photosensitizers

PubMed Central

Baier, Jürgen; Maisch, Tim; Maier, Max; Engel, Eva; Landthaler, Michael; Bäumler, Wolfgang

2006-01-01

UVA light (320–400 nm) has been shown to produce deleterious biological effects in tissue due to the generation of singlet oxygen by substances like flavins or urocanic acid. Riboflavin, flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), β-nicotinamide adenine dinucleotide (NAD), and β-nicotinamide adenine dinucleotide phosphate (NADP), urocanic acid, or cholesterol in solution were excited at 355 nm. Singlet oxygen was directly detected by time-resolved measurement of its luminescence at 1270 nm. NAD, NADP, and cholesterol showed no luminescence signal possibly due to the very low absorption coefficient at 355 nm. Singlet oxygen luminescence of urocanic acid was clearly detected but the signal was too weak to quantify a quantum yield. The quantum yield of singlet oxygen was precisely determined for riboflavin (ΦΔ = 0.54 ± 0.07), FMN (ΦΔ = 0.51 ± 0.07), and FAD (ΦΔ = 0.07 ± 0.02). In aerated solution, riboflavin and FMN generate more singlet oxygen than exogenous photosensitizers such as Photofrin, which are applied in photodynamic therapy to kill cancer cells. With decreasing oxygen concentration, the quantum yield of singlet oxygen generation decreased, which must be considered when assessing the role of singlet oxygen at low oxygen concentrations (inside tissue). PMID:16751234

Modelling the photochemical pollution over the metropolitan area of Porto Alegre, Brazil

NASA Astrophysics Data System (ADS)

Borrego, C.; Monteiro, A.; Ferreira, J.; Moraes, M. R.; Carvalho, A.; Ribeiro, I.; Miranda, A. I.; Moreira, D. M.

2010-01-01

The main purpose of this study is to evaluate the photochemical pollution over the Metropolitan Area of Porto Alegre (MAPA), Brazil, where high concentrations of ozone have been registered during the past years. Due to the restricted spatial coverage of the monitoring air quality network, a numerical modelling technique was selected and applied to this assessment exercise. Two different chemistry-transport models - CAMx and CALGRID - were applied for a summer period, driven by the MM5 meteorological model. The meteorological model performance was evaluated comparing its results to available monitoring data measured at the Porto Alegre airport. Validation results point out a good model performance. It was not possible to evaluate the chemistry models performance due to the lack of adequate monitoring data. Nevertheless, the model intercomparison between CAMx and CALGRID shows a similar behaviour in what concerns the simulation of nitrogen dioxide, but some discrepancies concerning ozone. Regarding the fulfilment of the Brazilian air quality targets, the simulated ozone concentrations surpass the legislated value in specific periods, mainly outside the urban area of Porto Alegre. The ozone formation is influenced by the emission of pollutants that act as precursors (like the nitrogen oxides emitted at Porto Alegre urban area and coming from a large refinery complex) and by the meteorological conditions.

Numerical Methods for the Analysis of Power Transformer Tank Deformation and Rupture Due to Internal Arcing Faults

PubMed Central

Yan, Chenguang; Hao, Zhiguo; Zhang, Song; Zhang, Baohui; Zheng, Tao

2015-01-01

Power transformer rupture and fire resulting from an arcing fault inside the tank usually leads to significant security risks and serious economic loss. In order to reveal the essence of tank deformation or explosion, this paper presents a 3-D numerical computational tool to simulate the structural dynamic behavior due to overpressure inside transformer tank. To illustrate the effectiveness of the proposed method, a 17.3MJ and a 6.3MJ arcing fault were simulated on a real full-scale 360MVA/220kV oil-immersed transformer model, respectively. By employing the finite element method, the transformer internal overpressure distribution, wave propagation and von-Mises stress were solved. The numerical results indicate that the increase of pressure and mechanical stress distribution are non-uniform and the stress tends to concentrate on connecting parts of the tank as the fault time evolves. Given this feature, it becomes possible to reduce the risk of transformer tank rupture through limiting the fault energy and enhancing the mechanical strength of the local stress concentrative areas. The theoretical model and numerical simulation method proposed in this paper can be used as a substitute for risky and costly field tests in fault overpressure analysis and tank mitigation design of transformers. PMID:26230392

Numerical Methods for the Analysis of Power Transformer Tank Deformation and Rupture Due to Internal Arcing Faults.

PubMed

Yan, Chenguang; Hao, Zhiguo; Zhang, Song; Zhang, Baohui; Zheng, Tao

2015-01-01

Power transformer rupture and fire resulting from an arcing fault inside the tank usually leads to significant security risks and serious economic loss. In order to reveal the essence of tank deformation or explosion, this paper presents a 3-D numerical computational tool to simulate the structural dynamic behavior due to overpressure inside transformer tank. To illustrate the effectiveness of the proposed method, a 17.3 MJ and a 6.3 MJ arcing fault were simulated on a real full-scale 360MVA/220kV oil-immersed transformer model, respectively. By employing the finite element method, the transformer internal overpressure distribution, wave propagation and von-Mises stress were solved. The numerical results indicate that the increase of pressure and mechanical stress distribution are non-uniform and the stress tends to concentrate on connecting parts of the tank as the fault time evolves. Given this feature, it becomes possible to reduce the risk of transformer tank rupture through limiting the fault energy and enhancing the mechanical strength of the local stress concentrative areas. The theoretical model and numerical simulation method proposed in this paper can be used as a substitute for risky and costly field tests in fault overpressure analysis and tank mitigation design of transformers.

The prototype fast reactor at Dounreay, Scotland. Process and engineering development for sodium removal

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

Mann, A.; Herrick, R.; Gunn, J.

2007-07-01

Dounreay was home to commercial fast reactor development in the UK. Following the construction and operation of the Dounreay Fast Reactor, a sodium-cooled Prototype Fast Reactor (PFR), was constructed. PFR started operating in 1974, closed in 1994 and is presently being decommissioned. To date the bulk of the sodium has been removed and treated. Due to the design of the existing extraction system however, a sodium pool will remain in the heel of the reactor. To remove this sodium, a pump/camera system was developed, tested and deployed. The Water Vapour Nitrogen (WVN) process has been selected to allow removal ofmore » the final sodium residues from the reactor. Due to the design of the reactor and potential for structural damage should Normal WVN (which produces hydrated sodium hydroxide) be used, Low Concentration WVN (LC WVN) has been developed. Pilot scale testing has shown that it is possible treat the reactor within 18 months at a WVN concentration of up to 4% v/v and temperature of 120 deg. C. At present the equipment that will be used to apply LC WVN to the reactor is being developed at the detail design stage. and is expected to be deployed within the next few years. (authors)« less

Polybrominated diphenyl ether metabolism in field collected fish from the Gila River, Arizona, USA-Levels, possible sources, and patterns

USGS Publications Warehouse

Echols, Kathy R.; Peterman, Paul H.; Hinck, Jo Ellen; Orazio, Carl E.

2013-01-01

Polybrominated diphenyl ethers (PBDEs) were determined in fish collected from the Gila River, Arizona, a tributary of the Colorado River in the lower part of the Colorado River Basin. Fish samples were collected at sites on the Gila River downstream from Hayden, Phoenix, and Arlington, Arizona in late summer 2003. The Gila River is ephemeral upstream of the Phoenix urban area due to dams and irrigation projects and has limited perennial flow downstream of Phoenix due to wastewater and irrigation return flows. Fifty PBDE congeners were analyzed by high resolution gas chromatography/high resolution mass spectrometry using labeled surrogate standards in composite samples of male and female common carp (Cyrpinus carpio), largemouth bass (Micropterus salmoides) and channel catfish (Ictalurus punctatus). The predominant PBDE congeners detected and quantified were 47, 100, 153, 49, 28, and 17. Concentrations of total PBDEs in these fish ranged from 1.4 to 12700 ng g-1 wet weight, which are some of the highest concentrations reported in fish from the United States. Differences in metabolism of several PBDE congeners by carp is clear at the Phoenix site; congeners with at least one ring of 2,4,5-substitution are preferentially metabolized as are congeners with 2,3,4-substitution.

Performance of a zero valent iron-based anaerobic system in swine wastewater treatment.

PubMed

Wu, Donglei; Zheng, Shuangshuang; Ding, Aqiang; Sun, Guodong; Yang, Meiqing

2015-04-09

In this paper, short-term exposure experiments with different ZVI concentrations were conducted to research the effects of ZVI adding on the anaerobic system for treating swine wastewater. Increasing the ZVI dose had a stimulatory effect on COD removal and CH4 production possibly due to a higher corrosion-induced H2 and dissolved ferrous ions, which could stimulate the methanogenesis and thus the biodegradation. In addition, the abiotic corrosion reactions such as flocculation, adsorption and precipitation were inevitable to removal some suspended COD. However, high ZVI doses had a potential risk on microorganism due to the present of large numbers of solid iron species in sludge, which likely encapsulated the cells and even damaged the cellular structure. Taken as a whole, the most enhancing effect induced by ZVI was observed at the rZVI/VSS of 2.63, and the maximum efficiency of per ZVI adding occurred at the rZVI/VSS of 0.74. But the ZVI concentration of 50 g/L (the rZVI/VSS was 5.26) was proved too high to facilitate microorganism activity, considering the higher LDH leakage and lower intracellular ATP level than the only sludge system. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantitative correlation between the void morphology of niobium-tin wires and their irreversible critical current degradation upon mechanical loading.

PubMed

Barth, C; Seeber, B; Rack, A; Calzolaio, C; Zhai, Y; Matera, D; Senatore, C

2018-04-26

Understanding the critical current performance variation of Nb 3 Sn superconducting wires under mechanical loading is a crucial issue for the design of next generation accelerator and fusion magnets. In these applications, the mechanical properties of the conductors may become a limiting factor due to the strong electro-magnetic forces resulting from the combination of large magnets and intense magnetic fields. In particular, the presence of voids in the superconducting filament structure, which are formed during the fabrication and the reaction heat treatment, determines localized stress concentrations and possibly the formation of cracks. In this work, we demonstrate a quantitative correlation between the void morphology and the electro-mechanical limits measured on different Bronze route Nb 3 Sn wires. Hot Isostatic Pressing (HIP) prior to the reaction heat treatment is utilized to partially eliminate the voids. The wires' void distributions - with and without HIP treatment - are detected and statistically analyzed using high energy X-ray micro tomography. The stress concentration due to the shape and distribution of the voids as well as their impact on the electro-mechanical properties are determined through finite element method modeling. Finally, the results are quantitatively correlated with the experimentally determined limits of the irreversible critical current degradation upon mechanical loading.

Probabilistic risk model to assess the potential for resistance selection following the use of anti-microbial medicated feed in pigs.

PubMed

Filippitzi, Maria Eleni; Chantziaras, Ilias; Devreese, Mathias; Dewulf, Jeroen

2018-05-30

The cross-contamination of non-medicated feed with residues of anti-microbials (AM) causes a public and animal health concern associated with the potential for selection and dissemination of resistance. To analyse the associated risks, a probabilistic model was built using @Risk® (Palisade Corporation®) to show the potential extent of the effect of cross-contaminated pig feed on resistance selection. The results of the model include estimations of the proportion of pigs per production stage with residues of doxycycline, chlortetracycline, sulfadiazine and trimethoprim in their intestinal contents, as a result of exposure to cross-contaminated feed with different carry-over levels, in Belgium. By using a semi-quantitative approach, these estimations were combined with experimental data on AM concentrations associated with potential for resistance-selection pressure. Based on this model, it is estimated that 7.76% (min = 1.67; max = 36.94) of sows, 4.23% (min = 1.01%; max = 18.78%) of piglets and 2.8% (min = 0.51%; max = 14.9%) of fatteners in Belgium have residues of doxycycline in their intestinal tract due to consumption of feed with at least 1% carry-over. These values were estimated to be almost triple for sulfadiazine, but substantially lower for chlortetracycline and trimethoprim. Doxycycline concentrations as low as 1 mg/L (corresponding to consumed feed with at least 1% carry-over) can select for resistant porcine commensal Escherichia coli in vitro and in vivo. Conclusions on this risk could not be drawn for other AM at this stage, due to the lack of data on concentrations associated with resistance development. However, since the possibility of resistance mechanisms (e.g. co-selection) occurring cannot be excluded, the results of this model highlight that the use of AM medicated feed should be minimised where possible. In case of medicated feed production, good practice should be followed thoroughly at all levels of production, distribution, storage and administration, with a special focus on the feed distributed to piglets and sows.

New Possibilities for the Accurate in Situ Determination of Chalcophile and Siderophile Trace Elements by Laser Ablation Collision and Reaction Cell ICP-MS

NASA Astrophysics Data System (ADS)

Mason, P. R.

2004-05-01

Our knowledge of how chalcophile and siderophile elements partition in minerals is limited, mainly due to the lack of suitable techniques for their accurate in situ determination. Host minerals (e.g. sulphides) are typically of small size (<30 μ m) and highly heterogeneous in composition, requiring analysis of high spatial resolution. Concentrations of chalcophile elements in silicates and oxides are low (sub μ gg-1) and thus challenging to measure. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), offering high sensitivity and good spatial resolution (10-100 μ m) is thus highly suited for this purpose. Unfortunately, the widespread use of this technique has been limited by enhanced problems specific to chalcophile and siderophile elements. These include inaccuracy due to the presence of spectral interferences, elemental fractionation during ablation/ionization and the lack of suitable calibration standards. Polyatomic spectral interferences, present either as a background component (e.g. O2+, ArAr+) or based around the recombination of matrix elements with argon (e.g. ArS+, ArNi+) hinder accurate analysis. These depend upon the relative concentrations of major matrix components and trace elements to be measured and are significant in many relevant minerals (e.g. sulphides). The use of a collision and reaction cells in ICP-MS is a new method for selective interference attenuation, significantly improving detection limits for elements such as Fe, S and Se by between 1 and 4 orders of magnitude. ArNi+ and ArCu+ interferences in sulphides can be attenuated by at least an order of magnitude leading to improved accuracy for the measurement of the Platinum Group elements Rh and Ru. Sulphur isotopes can be measured interference-free at m/z=32 and 34 by eliminating background O2+. These improvements open up new possibilities for the use of LA-ICP-MS in trace element and isotopic studies at the lowest concentration levels or where sample preparation creates additional problems (e.g. NiS fire assay beads). I will give examples of applications for this technique in the study of ore minerals, meteorites and precipitates from hydrothermal vents.

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

Wang, Ying; Qi, Long; Wu, Yihong, E-mail: elewuyh@nus.edu.sg

Few-layer MoS{sub 2} field-effect transistors often show an n-type conduction behavior due to the presence of high-density sulfur vacancies. Here, we investigated the possibility of surface defect passivation of MoS{sub 2} by sulfur treatment in (NH{sub 4}){sub 2}S solution or coating with an ultrathin layer of selenium or tellurium. It was found that all three elements investigated are able to induce a p-doping effect through suppressing the residual electron concentration by an amount exceeding 0.5 × 10{sup 12 }cm{sup −2} in few-layer MoS{sub 2}. Among them, the sulfur-treatment exhibits the most superior thermal stability that survives thermal annealing at temperatures ≥120 °C for atmore » least 10 h. Tellurium exhibits the strongest p-doping effect due to electron trapping by physisorption-induced gap states near the valence band edge. On the other hand, selenium is highly volatile on MoS{sub 2}; it evaporates and desorbs easily due to Joule heating during electrical measurements in vacuum. The results of first-principles calculations support the experimental observations.« less

Contemporary Trends in the Acid-Base Status of the Two Acid-Sensitive Streams in Western Maryland

NASA Technical Reports Server (NTRS)

Eshleman, Keith N.; Kline, Kathleen M.; Morgan, Raymond P., II; Castro, Nancy M.; Negley, Timothy L.

2008-01-01

Recovery of streamwater acid neutralizing capacity (ANC) resulting from declines in regional acid deposition was examined using contemporary (1990-2005) data from two long-term monitoring stations located on the Appalachian Plateau in western Maryland, U.S. Two computational methods were used to estimate daily, monthly, and annual fluxes and discharge-weighted concentrations of ANC, sulfate, nitrate, and base cations over the period of record, and two statistical methods were used to evaluate long-term trends in fluxes and concentrations. The methods used to estimate concentrations, as well as the, statistical techniques, produced very similar results, underlining the robustness of the identified trends. We found clear evidence that streamwater sulfate concentrations have declined at an average rate of about 3 (microns)eq L(exp -1) yr(exp -1) at the two sites due to a 34% reduction in wet atmospheric sulfur deposition. Trends in nitrate concentrations appear to be related to other watershed factors, especially forest disturbance. The best evidence of recovery is based on a doubling of ANC (from 21 to 42 (microns)eq L(exp -1) at the more acid-sensitive site over the 16-year period. A slowing, or possible reversal, in the sulfate, nitrate, and SBC trends is evident in our data and may portend a decline in the rate of--or end to--further recovery.

Patterns of protein–protein interactions in salt solutions and implications for protein crystallization

PubMed Central

Dumetz, André C.; Snellinger-O'Brien, Ann M.; Kaler, Eric W.; Lenhoff, Abraham M.

2007-01-01

The second osmotic virial coefficients of seven proteins—ovalbumin, ribonuclease A, bovine serum albumin, α-lactalbumin, myoglobin, cytochrome c, and catalase—were measured in salt solutions. Comparison of the interaction trends in terms of the dimensionless second virial coefficient b2 shows that, at low salt concentrations, protein–protein interactions can be either attractive or repulsive, possibly due to the anisotropy of the protein charge distribution. At high salt concentrations, the behavior depends on the salt: In sodium chloride, protein interactions generally show little salt dependence up to very high salt concentrations, whereas in ammonium sulfate, proteins show a sharp drop in b2 with increasing salt concentration beyond a particular threshold. The experimental phase behavior of the proteins corroborates these observations in that precipitation always follows the drop in b2. When the proteins crystallize, they do so at slightly lower salt concentrations than seen for precipitation. The b2 measurements were extended to other salts for ovalbumin and catalase. The trends follow the Hofmeister series, and the effect of the salt can be interpreted as a water-mediated effect between the protein and salt molecules. The b2 trends quantify protein–protein interactions and provide some understanding of the corresponding phase behavior. The results explain both why ammonium sulfate is among the best crystallization agents, as well as some of the difficulties that can be encountered in protein crystallization. PMID:17766383

Effect of ubiquinol-10 on citral stability and off-flavor formation in oil-in-water (O/W) nanoemulsions.

PubMed

Zhao, Qin; Ho, Chi-Tang; Huang, Qingrong

2013-08-07

The effects of different concentrations of ubiquinol-10 (Q10H2) on citral's stability were systematically investigated and compared in citral-loaded oil-in-water (O/W) nanoemulsions. Solid phase microextraction gas chromatography (SPME-GC) was employed to monitor the degradation of citral and the formation of off-flavor compounds throughout storage at 25 and 45 °C. The optimum concentration of Q10H2 in the current formulation was determined to be around 0.10 wt % in the system (Q10H2/citral ratio 1:1), which can effectively protect citral from chemical degradation and oxidation. Results suggested, however, that a low concentration of Q10H2 may induce the majority of the ubisemiquinone (Q10(•-))/ubiquinone (Q10) redox transition, which possibly endowed Q10H2 with pro-oxidant properties. Further increase in Q10H2 concentration beyond a certain value also hindered its effect due to the complex properties of radicals involved and the overall environment encountered. With appropriate concentrations of Q10H2 presented in the system, major citral oxidation off-flavor compounds (p-cresol, α,p-dimethylstyrene, p-methylacetophenone), and some of the lipid degradation products can be inhibited to lower levels. In contrast, ubiquinone-10 (Q10) had a negligible effect on citral's chemical stability and off-flavor generation.

Delineation of salt water intrusion through use of electromagnetic-induction logging: A case study in Southern Manhattan Island, New York

USGS Publications Warehouse

Stumm, Frederick; Como, Michael D.

2017-01-01

Groundwater with chloride concentrations up to 15,000 mg/L has intruded the freshwater aquifer underlying southern Manhattan Island, New York. Historical (1940–1950) chloride concentration data of glacial aquifer wells in the study area indicate the presence of four wedges of saltwater intrusion that may have been caused by industrial pumpage. The limited recharge capability of the aquifer, due to impervious surfaces and the 22.7 million liters per day (mld) of reported industrial pumpage early in the 20th Century was probably the cause for the saltwater intrusion and the persistence of the historical saltwater intrusion wedges over time. Recent drilling of wells provided new information on the hydrogeology and extent of saltwater intrusion of the glacial aquifer overlying bedrock. The new observation wells provided ground-water level, chloride concentration, hydraulic conductivity, and borehole geophysical data of the glacial aquifer. The glacial sediments range in thickness from less than 0.3 m to more than 76.2 m within the study area. A linear relation between Electromagnetic-induction (EM) conductivity log response and measured chloride concentration was determined. Using this relation, chloride concentration was estimated in parts of the glacial aquifer where sampling was not possible. EM logging is an effective tool to monitor changes in saltwater intrusion wedges.

Possible causes of variation in acrylamide concentration in French fries prepared in food service establishments: an observational study.

PubMed

Sanny, M; Jinap, S; Bakker, E J; van Boekel, M A J S; Luning, P A

2012-05-01

Acrylamide is a probable human carcinogen, and its presence in a range of fried and oven-cooked foods has raised considerable health concern world-wide. Dietary intake studies observed significant variations in acrylamide concentrations, which complicate risk assessment and the establishment of effective control measures. The objective of this study was to obtain an insight into the actual variation in acrylamide concentrations in French fries prepared under typical conditions in a food service establishment (FSE). Besides acrylamide, frying time, frying temperature, and reducing sugars were measured and the actual practices at receiving, thawing and frying during French fries preparation were observed and recorded. The variation in the actual frying temperature contributed most to the variation in acrylamide concentrations, followed by the variation in actual frying time; no obvious effect of reducing sugars was found. The lack of standardised control of frying temperature and frying time (due to inadequate frying equipment) and the variable practices of food handlers seem to contribute most to the large variation and high acrylamide concentrations in French fries prepared in a restaurant type of FSE as compared to chain fast-food services, and institutional caterers. The obtained insights in this study can be used to develop dedicated control measures in FSE, which may contribute to a sustainable reduction in the acrylamide intake. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cytochrome P450 and ABCB1 genetics: association with quetiapine and norquetiapine plasma and cerebrospinal fluid concentrations and with clinical response in patients suffering from schizophrenia. A pilot study.

PubMed

Nikisch, Georg; Baumann, Pierre; Oneda, Beatrice; Kiessling, Bernhard; Weisser, Heike; Mathé, Aleksander A; Yoshitake, Takashi; Kehr, Jan; Wiedemann, Georg; Eap, Chin B

2011-07-01

Variability in response to atypical antipsychotic drugs is due to genetic and environmental factors. Cytochrome P450 (CYP) isoforms are implicated in the metabolism of drugs, while the P-glycoprotein transporter (P-gp), encoded by the ABCB1 gene, may influence both the blood and brain drug concentrations. This study aimed to identify the possible associations of CYP and ABCB1 genetic polymorphisms with quetiapine and norquetiapine plasma and cerebrospinal fluid (CSF) concentrations and with response to treatment. Twenty-two patients with schizophrenia receiving 600 mg of quetiapine daily were genotyped for four CYP isoforms and ABCB1 polymorphisms. Quetiapine and norquetiapine peak plasma and CSF concentrations were measured after 4 weeks of treatment. Stepwise multiple regression analysis revealed that ABCB1 3435C > T (rs1045642), 2677G > T (rs2032582) and 1236C > T (rs1128503) polymorphisms predicted plasma quetiapine concentrations, explaining 41% of the variability (p = 0.001). Furthermore, the ABCB1 polymorphisms predicted 48% (p = 0.024) of the variability of the Δ PANSS total score, with the non-carriers of the 3435TT showing higher changes in the score. These results suggest that ABCB1 genetic polymorphisms may be a predictive marker of quetiapine treatment in schizophrenia.

Impact of increased vehicle emissions on the ozone concentrations around beach areas in summer using air quality modeling system

NASA Astrophysics Data System (ADS)

Song, S.; Kim, Y.; Shon, Z.; Kang, Y.; Jeong, J.

2012-12-01

The impact of pollutant emissions by the huge amount of road traffic around beaches on the ozone (O3) concentrations in the surrounding regions were evaluated using a numerical modeling approach during the beach opening period (BOP) (July to August). This analysis was performed based on two simulation conditions: 1) with mobile emissions during the BOP (i.e. BOP case); and 2) during the normal period (i.e. NOR case). On-road mobile emissions were estimated from the emission factors, vehicle kilometers traveled, and deterioration factors at several roads close to beaches in Busan, Korea during a 4-day observation period (29 and 31 July and 1 and 3 August) of the BOP in 2010. The emission data was then applied to the 3-D chemical transport model (i.e. the WRF-CMAQ modeling system). A process analysis (PA) was also used to assess the contributions of the individual physical and chemical processes to the production or loss of O3 in the study area. The model study suggested the possibility that road traffic emissions near the beach area can have a direct impact on the O3 concentrations in the source regions as well as their surrounding/downwind regions. The maximum negative impact of mobile emissions on the O3 concentrations between the BOP and NOR cases was predicted near the beach areas: by -4 ppb during the day due to the high NOx emissions with the high NOx/VOC ratio and -8 ppb during the late evening due to the fast titration of O3 by NO. The PA showed that the rate of O3 destruction due to the road traffic emissions around the beach areas decreased by -2.3 (weekend, 31 July) and -5.5 ppb h-1 (weekday, 3 August) during the day. Acknowledgments: This work was funded by the Korea Meteorological Administration Research and Development Program under Grant CATER_2012-6140. This work was also funded by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0021141).

DNA Damage Dependence on the Subcellular Distribution of Low-Energy Beta Emitters

NASA Astrophysics Data System (ADS)

Cutaia, Claudia; Alloni, Daniele; Mariotti, Luca; Friedland, Werner; Ottolenghi, Andrea

One of the main issues of low-energy internal emitters is related to the short ranges of beta particles, compared to the dimensions of the biological targets (e.g. the cell nucleus). Also depending on the chemical form, the radionuclide may be more concentrated in the cytoplasm of the target cell (in our calculations a human fibroblast in interphase) and consequently the conventional dosimetry may overestimate the dose to the nucleus; whereas if the radionuclide is more concentrated in the nuclei of the cells there is a risk of underestimating the nucleus dose. The computer code PARTRAC was modified to calculate the energy depositions in the nucleus and the DNA damage for different relative concentrations of the radionuclide in the nucleus and in the cytoplasm. The nuclides considered in the simulations were Tritium (the electrons emitted due to the β - decay have an average energy of 5.7 keV, corresponding to an average range of 0.42 µm) and Nickel-63 (the electrons emitted have an average energy of 17 keV corresponding to an average range of 5 µm). In the case of Tritium, the dose in the nucleus due the tracks generated outside this region is 15% of the average dose in the cell, whereas in the case of Nickel-63 the dose in the nucleus resulted to be 64% of the average dose in the cell. The distributions of DNA fragments as a function of the relative concentration of the nuclides in the nucleus and in the cytoplasm, were also calculated. In the same conditions, the number of complex lesions (which have a high probability of inducing lethal damage to the cells) per Gy (circa 0.5-1) and the total number of double strand breaks (DSBs) per Gy (circa 40) were also calculated. To complete the characterization of the effects of internal emitters inside the cell the distributions of DSBs per chromosome were studied for different radionuclide distributions in the cell. The results obtained from these simulations show the possible overestimation or underestimation of the risk, (particularly for Tritium intake), due to the distribution of the low energy emitters at subcellular levels.

On the nature and shape of tubulin trails: implications on microtubule self-organization.

PubMed

Glade, Nicolas

2012-06-01

Microtubules, major elements of the cell skeleton are, most of the time, well organized in vivo, but they can also show self-organizing behaviors in time and/or space in purified solutions in vitro. Theoretical studies and models based on the concepts of collective dynamics in complex systems, reaction-diffusion processes and emergent phenomena were proposed to explain some of these behaviors. In the particular case of microtubule spatial self-organization, it has been advanced that microtubules could behave like ants, self-organizing by 'talking to each other' by way of hypothetic (because never observed) concentrated chemical trails of tubulin that are expected to be released by their disassembling ends. Deterministic models based on this idea yielded indeed like-looking spatio-temporal self-organizing behaviors. Nevertheless the question remains of whether microscopic tubulin trails produced by individual or bundles of several microtubules are intense enough to allow microtubule self-organization at a macroscopic level. In the present work, by simulating the diffusion of tubulin in microtubule solutions at the microscopic scale, we measure the shape and intensity of tubulin trails and discuss about the assumption of microtubule self-organization due to the production of chemical trails by disassembling microtubules. We show that the tubulin trails produced by individual microtubules or small microtubule arrays are very weak and not elongated even at very high reactive rates. Although the variations of concentration due to such trails are not significant compared to natural fluctuations of the concentration of tubuline in the chemical environment, the study shows that heterogeneities of biochemical composition can form due to microtubule disassembly. They could become significant when produced by numerous microtubule ends located in the same place. Their possible formation could play a role in certain conditions of reaction. In particular, it gives a mesoscopic basis to explain the collective dynamics observed in excitable microtubule solutions showing the propagation of concentration waves of microtubules at the millimeter scale, although we doubt that individual microtubules or bundles can behave like molecular ants.

Apportionment of particulate matter sources in the Rio de Janeiro Metropolitan area

NASA Astrophysics Data System (ADS)

Gioda, A.; Mateus, V.; Ventura, L.; Amaral, B.

2013-05-01

Continuous monitoring of particulate matter (PM) is extremely important in order to observe possible trends and take measures to reduce emissions. In Brazil, few cities have network stations, which make these measurements even more crucial. Furthermore, there is a need to update and create new standards of air quality, which can only be done based on a suitable inventory. Levels of total suspended particles (TSP), PM10 and PM2.5 were monitored in the Metropolitan area of Rio de Janeiro. Mean concentrations of TSP, PM10 and PM2.5 were 70, 60 and 14 μg/m3, respectively. Some of the monitored sampling points exceeded the Brazilian guidelines for PM10 (50 μg/m3) and TSP (80 μg/m3). However, the PM2.5 levels measured in the present study are of extreme concern, since they exceeded the guideline suggested by the World Health Organization (WHO - 10 μg/m3) in almost all the study sites. The average PM2.5/PM10 ratios ranged from 0.1 to 0.3, being more dependent on traffic emissions, while PM10/PTS ratios ranged from 0.6 to 0.7. The particles were composed mainly of soil elements (~50%) and ammonium sulfate and ammonium nitrate (20-40%), which are recognized as secondary inorganic aerosols. Rural areas and sites near the ocean presented the lowest levels for all particle sizes. This is probably due to an enhanced dispersion of the particles by the sea breeze. On the other hand, higher PM concentrations were observed for the sites near industrial areas and heavy traffic, as expected. The monthly distribution profile observed for PM showed clear increases in PM levels from May to September at all stations. This increase is due to the stagnation of the air during winter, which is related to meteorological processes such as low relative humidity and low rainfall. Consequently, due to this stagnation pollutant concentrations show increases. According to the dataset from the Unified Health System there is a clear trend of increased hospitalizations for respiratory diseases in winter, when increased concentrations of PM are observed, which was verified in this study.

Ketamine coadministration attenuates morphine tolerance and leads to increased brain concentrations of both drugs in the rat

PubMed Central

Lilius, T O; Jokinen, V; Neuvonen, M S; Niemi, M; Kalso, E A; Rauhala, P V

2015-01-01

Background and Purpose The effects of ketamine in attenuating morphine tolerance have been suggested to result from a pharmacodynamic interaction. We studied whether ketamine might increase brain morphine concentrations in acute coadministration, in morphine tolerance and morphine withdrawal. Experimental Approach Morphine minipumps (6 mg·day–1) induced tolerance during 5 days in Sprague–Dawley rats, after which s.c. ketamine (10 mg·kg–1) was administered. Tail flick, hot plate and rotarod tests were used for behavioural testing. Serum levels and whole tissue brain and liver concentrations of morphine, morphine-3-glucuronide, ketamine and norketamine were measured using HPLC-tandem mass spectrometry. Key Results In morphine-naïve rats, ketamine caused no antinociception whereas in morphine-tolerant rats there was significant antinociception (57% maximum possible effect in the tail flick test 90 min after administration) lasting up to 150 min. In the brain of morphine-tolerant ketamine-treated rats, the morphine, ketamine and norketamine concentrations were 2.1-, 1.4- and 3.4-fold, respectively, compared with the rats treated with morphine or ketamine only. In the liver of morphine-tolerant ketamine-treated rats, ketamine concentration was sixfold compared with morphine-naïve rats. After a 2 day morphine withdrawal period, smaller but parallel concentration changes were observed. In acute coadministration, ketamine increased the brain morphine concentration by 20%, but no increase in ketamine concentrations or increased antinociception was observed. Conclusions and Implications The ability of ketamine to induce antinociception in rats made tolerant to morphine may also be due to increased brain concentrations of morphine, ketamine and norketamine. The relevance of these findings needs to be assessed in humans. PMID:25297798

Comparative Analysis of Fluoride Concentrations in Groundwaters in Northern and Southern Ghana: Implications for the Contaminant Sources

NASA Astrophysics Data System (ADS)

Sunkari, Emmanuel Daanoba; Zango, Musah Saeed; Korboe, Harriet Mateko

2018-04-01

Bongo and Sekyere South districts, both in the northern and southern parts of Ghana, respectively, have high populations living in rural areas and most of them use groundwater for drinking purposes. The groundwater in these areas is prone to contamination from natural and/or artificial sources. Therefore this study aims; (1) to present a comparative analysis of the fluoride concentration in groundwater samples from Bongo and Sekyere South districts and the associated groundwater-rock interaction that may be the cause for the varied fluoride concentrations, (2) to determine the leaching potential of fluoride from the host rocks as the possible mechanism for groundwater contamination. Sixty (60) groundwater samples from active pumping wells and twelve (12) rock samples from outcrops were collected from various communities in the two districts for fluoride concentration and mineralogical analysis. Based on the variations in fluoride concentration, fluoride spatial distribution maps were prepared using empirical Bayesian kriging interpolation method and analysed by means of hierarchical cluster analysis. The fluoride concentration in Bongo district varies between 1.71 and 4.0 mg/L, whereas that in Sekyere South district changes from 0.3 to 0.8 mg/L. From the mineralogical studies, biotite has the highest percentage in the Bongo district and has positive correlation with fluoride concentration in the analysed water samples than in the Sekyere South district. The elevated fluoride concentration in the Bongo district relative to the Sekyere South district is due to the dissolution of biotite in the groundwater and the sufficient groundwater-rock interaction since the water samples are mainly sourced from deeper boreholes. This high fluoride concentration has resulted in a plethora of reported cases of dental fluorosis and other health-related issues in Bongo.

Comparative Analysis of Fluoride Concentrations in Groundwaters in Northern and Southern Ghana: Implications for the Contaminant Sources

NASA Astrophysics Data System (ADS)

Sunkari, Emmanuel Daanoba; Zango, Musah Saeed; Korboe, Harriet Mateko

2018-05-01

Bongo and Sekyere South districts, both in the northern and southern parts of Ghana, respectively, have high populations living in rural areas and most of them use groundwater for drinking purposes. The groundwater in these areas is prone to contamination from natural and/or artificial sources. Therefore this study aims; (1) to present a comparative analysis of the fluoride concentration in groundwater samples from Bongo and Sekyere South districts and the associated groundwater-rock interaction that may be the cause for the varied fluoride concentrations, (2) to determine the leaching potential of fluoride from the host rocks as the possible mechanism for groundwater contamination. Sixty (60) groundwater samples from active pumping wells and twelve (12) rock samples from outcrops were collected from various communities in the two districts for fluoride concentration and mineralogical analysis. Based on the variations in fluoride concentration, fluoride spatial distribution maps were prepared using empirical Bayesian kriging interpolation method and analysed by means of hierarchical cluster analysis. The fluoride concentration in Bongo district varies between 1.71 and 4.0 mg/L, whereas that in Sekyere South district changes from 0.3 to 0.8 mg/L. From the mineralogical studies, biotite has the highest percentage in the Bongo district and has positive correlation with fluoride concentration in the analysed water samples than in the Sekyere South district. The elevated fluoride concentration in the Bongo district relative to the Sekyere South district is due to the dissolution of biotite in the groundwater and the sufficient groundwater-rock interaction since the water samples are mainly sourced from deeper boreholes. This high fluoride concentration has resulted in a plethora of reported cases of dental fluorosis and other health-related issues in Bongo.

Range of therapeutic prothipendyl and prothipendyl sulfoxide concentrations in clinical blood samples.

PubMed

Krämer, Michael; Heese, Peter; Banger, Markus; Madea, Burkhard; Hess, Cornelius

2018-06-01

Due to a lack of reference blood concentrations in the literature, the forensic evaluation of prothipendyl findings in blood samples is difficult. Interpretations with regard to the assessment of blood concentrations as well as an estimation of the ingested prothipendyl amounts were often vague. To describe a concentration range in clinical samples, prothipendyl and prothipendyl sulfoxide concentrations were determined in serum samples of 50 psychiatric patients receiving 40 mg, 80 mg, or 160 mg doses of prothipendyl. The analyses of prothipendyl and prothipendyl sulfoxide were carried out using validated methods of high performance liquid chromatography coupled to triple quadrupole mass spectrometry (LC-QQQ-MS), respectively. 40 mg doses caused average prothipendyl serum concentrations of 18.0 ng/mL (1 hour after intake) and 7.9 ng/mL (10.5 hours after intake), while 80 mg doses caused averages of 42.6 ng/mL and 15.2 ng/mL at the mentioned times of sampling. Irrespective of the given dose, prothipendyl concentrations below 30 ng/mL were observed in 80% of the patient samples taken 1 hour after ingestion as well as in 90% of the samples collected 10.5 hours after administration. Serum concentrations of the Phase I metabolite prothipendyl sulfoxide averaged 4.3 ng/mL (1 hour after intake) and 3.6 ng/mL (10.5 hours after intake). Possible drug-drug interactions regarding absorption and metabolism of prothipendyl are discussed. Results of the herein presented study are useful for the interpretation of analytical prothipendyl findings in forensic toxicology. The utility of the described concentration range is demonstrated by discussing two death cases involving prothipendyl findings. Copyright © 2017 John Wiley & Sons, Ltd.

Wet and Occult Ion Deposition To An Elevated Forest Ecosystem In Switzerland

NASA Astrophysics Data System (ADS)

Buetzberger, P.; Burkard, R.; Eugster, W.

Due to much higher ion concentrations in fogwater compared to rainwater, critical deposition levels of nutrients such as sulfate, nitrate or ammonium can be achieved in areas with high fog frequency. From summer 2001 until spring 2002 a measuring campaign of the FINIMSAS project (Fog Interception and Nutrient Inputs to Montane- Subalpine Areas in Switzerland) is being conducted at Laegeren (690m asl) on the Swiss Plateau. Fog frequency was high during our campaign. Similar measurements were carried out in 1986/87 at the exact same location, providing a reference data set for comparison. Because the deposition flux was measured differently during 1986/87, direct compar- isons are only possible for ion concentrations. Preliminary results show a significant decrease of sulfate and ammonium median concentrations of more than 50 % over this 15 year period, whereas nitrate decrease is relatively small. This corresponds well with the large-scale evolution of the air pollutant emissions of SO2 (major decrease) and NOx (relatively small decrease). The strong reduction of ammonium is probably due to the reduced use of fertilizer in the area. Chloride shows the largest decrease which can be attributed to the improvement of filtering technique of waste incinerations. In order to achieve maximum comparability, similar event types (e.g. advection fog vs. radiation fog) with similar meteorological conditions were interpreted individually. Analysis of fog nutrient input with respect to wind direction, wind speed, and origin of air mass will help to understand the influence of local and large-scale emissions on fog water concentrations in Switzerland. Computations based on half-hourly mean wind direction revealed significantly lower fog water input but higher median concentra- tions of all measured components if the dominating wind sector was East. Event-based wind field analyses were also carried out and compared to computed trajectories. In order to assess the influence of fog and rain water nutrient deposition on vegetation and soil, we measured throughfall precipitation close to the forest floor. Whereas fog water showed pH values as low as 3, throughfall water was between pH 6 and 7, indicating an important buffering capacity of this ecosystem mainly due to potassium leaching and probably calcium compounds. High ionic concentrations and low pH values seem to act mostly on the leaves.

Behavioural and hormonal effects of member replacement in captive groups of blue-fronted amazon parrots (Amazona aestiva).

PubMed

Silva de Souza Matos, Laerciana; Palme, Rupert; Silva Vasconcellos, Angélica

2017-05-01

Social species in captivity may face allostatic overload due to artificial grouping and other social constraints. In rescue centres, groups of psittacines are constantly mixed due to the arrival and/or release of individuals; this procedure is potentially harmful to animal welfare. This study aimed at evaluating the possible impacts of mate replacement on the stress levels of captive blue-fronted amazon parrots (Amazona aestiva). During five weeks, we recorded agonistic interactions and dropping-glucocorticoid metabolites (GCM) concentrations of individuals allocated in a group whose members were kept constant and in a group subjected to frequent member replacement. In both groups, non-linear hierarchies developed, without sex differences regarding aggression or hierarchical positions. The replacement of individuals had no effect on the number of agonistic interactions or on the animals' stress levels. In both groups, higher-ranking individuals had higher stress loads than subordinates. Our study, the first to investigate the social dynamics of A. aestiva, indicated that introducing or removing individuals in captive groups does not seem to affect the welfare of the birds in the short term. This information favours release and reintroduction programs and is relevant for conservation management of this, and possibly other parrot species with similar environmental requirements. Copyright © 2017 Elsevier B.V. All rights reserved.

HPTLC-aptastaining - Innovative protein detection system for high-performance thin-layer chromatography

NASA Astrophysics Data System (ADS)

Morschheuser, Lena; Wessels, Hauke; Pille, Christina; Fischer, Judith; Hünniger, Tim; Fischer, Markus; Paschke-Kratzin, Angelika; Rohn, Sascha

2016-05-01

Protein analysis using high-performance thin-layer chromatography (HPTLC) is not commonly used but can complement traditional electrophoretic and mass spectrometric approaches in a unique way. Due to various detection protocols and possibilities for hyphenation, HPTLC protein analysis is a promising alternative for e.g., investigating posttranslational modifications. This study exemplarily focused on the investigation of lysozyme, an enzyme which is occurring in eggs and technologically added to foods and beverages such as wine. The detection of lysozyme is mandatory, as it might trigger allergenic reactions in sensitive individuals. To underline the advantages of HPTLC in protein analysis, the development of innovative, highly specific staining protocols leads to improved sensitivity for protein detection on HPTLC plates in comparison to universal protein derivatization reagents. This study aimed at developing a detection methodology for HPTLC separated proteins using aptamers. Due to their affinity and specificity towards a wide range of targets, an aptamer based staining procedure on HPTLC (HPTLC-aptastaining) will enable manifold analytical possibilities. Besides the proof of its applicability for the very first time, (i) aptamer-based staining of proteins is applicable on different stationary phase materials and (ii) furthermore, it can be used as an approach for a semi-quantitative estimation of protein concentrations.

Salting-out and salting-in: competitive effects of salt on the aggregation behavior of soy protein particles and their emulsifying properties.

PubMed

Xu, Hua-Neng; Liu, Yang; Zhang, Lianfu

2015-08-07

Emulsions stabilized by protein particles have gained increasing research attention due to their combined advantages of biocompatibility and superior stability. In this study, colloidal particles consisting of soy protein isolates (SPIs) prepared through a heat-treatment procedure are used to make oil-in-water emulsions at a protein concentration of 10 g L(-1) and a pH of 5.91. We investigate parallelly the effects of NaCl on the stability and rheological properties of the particle suspensions and their stabilized emulsions at salt concentrations of 0, 100 and 400 mM. The aggregation behavior of the particles is strongly dependent on the NaCl concentration, showing signs of sedimentation at low NaCl concentration (100 mM) but redispersion again at high NaCl concentration (400 mM). The extensive particle aggregation is beneficial to the formation of a continuous interfacial film for the emulsions, and hence results in a remarkable increase of creaming stability and interfacial viscoelastic moduli. The results can be explained in terms of two competitive effects of NaCl: salting-out and salting-in, which are attributed to complex electrostatic interactions between the particles as a function of NaCl concentration. The delicate balance between salting-out and salting-in provides an interesting insight into the nature of underlying protein particle interactions in aqueous suspensions and a possible mechanism for tailoring their emulsifying properties via salt effects.

Thyroglobulin assay in fluids from lymph node fine needle-aspiration washout: influence of pre-analytical conditions.

PubMed

Casson, Florence Boux de; Moal, Valérie; Gauchez, Anne-Sophie; Moineau, Marie-Pierre; Sault, Corinne; Schlageter, Marie-Hélène; Massart, Catherine

2017-04-01

The aim of this study was to evaluate the pre-analytical factors contributing to uncertainty in thyroglobulin measurement in fluids from fine-needle aspiration (FNA) washout of cervical lymph nodes. We studied pre-analytical stability, in different conditions, of 41 samples prepared with concentrated solutions of thyroglobulin (FNA washout or certified standard) diluted in physiological saline solution or buffer containing 6% albumin. In this buffer, over time, no changes in thyroglobulin concentrations were observed in all storage conditions tested. In albumin free saline solution, thyroglobulin recovery rates depended on initial sample concentrations and on modalities of their conservation (in conventional storage tubes, recovery mean was 56% after 3 hours-storage at room temperature and 19% after 24 hours-storage for concentrations ranged from 2 to 183 μg/L; recovery was 95%, after 3 hours or 24 hours-storage at room temperature, for a concentration of 5,656 μg/L). We show here that these results are due to non-specific adsorption of thyroglobulin in storage tubes, which depends on sample protein concentrations. We also show that possible contamination of fluids from FNA washout by plasma proteins do not always adequately prevent this adsorption. In conclusion, non-specific adsorption in storage tubes strongly contributes to uncertainty in thyroglobulin measurement in physiological saline solution. It is therefore recommended, for FNA washout, to use a buffer containing proteins provided by the laboratory.

Environmental 238U and 232Th concentration measurements in an area of high level natural background radiation at Palong, Johor, Malaysia.

PubMed

Ramli, A Termizi; Hussein, A Wahab M A; Wood, A Khalik

2005-01-01

Concentrations of uranium-238 and thorium-232 in soil, water, grass, moss and oil-palm fruit samples collected from an area of high background radiation were determined using neutron activation analysis (NAA). U-238 concentration in soil ranged from 4.9 mg kg(-1) (58.8 Bq kg(-1)) to 40.4 mg kg(-1) (484.8 Bq kg(-1)), Th-232 concentration ranged from 14.9 mg kg(-1) (59.6 Bq kg(-1)) to 301.0 mg kg(-1) (1204 Bq kg(-1)). The concentration of U-238 in grass samples ranged from below the detection limit to 0.076 mg kg(-1) (912 mBq kg(-1)), and Th-232 ranged from 0.008 mg kg(-1) (32 mBq kg(-1)) to 0.343 mg kg(-1) (1.372 Bq kg(-1)). U-238 content in water samples ranged from 0.33 mg kg(-1) (4.0 Bq L(-1)) to 1.40 mg kg(-1) (16.8 Bq L(-1)), and Th-232 ranged from 0.19 mg kg(-1) (0.76 Bq L(-1)) to 0.66 mg kg(-1) (2.64 Bq L(-1)). It can be said that the concentrations of environmental U-238 and Th-232 in grass and water samples in the study area are insignificant. Mosses were found to be possible bio-radiological indicators due to their high absorption of the heavy radioelements from the environment.

Assessing exposure to diesel exhaust particles: a case study.

PubMed

See, Siao Wei; Balasubramanian, Rajasekhar; Yang, Tzuo Sern; Karthikeyan, Sathrugnan

2006-11-01

The assessment of the vehicular contributions to urban pollution levels is of particular importance given the current interest in the possible adverse health effects. This study focused on human exposure to diesel-engine-derived particulate matter. Diesel vehicles are known to emit fine particulate matter (PM2.5) containing carcinogens such as polycyclic aromatic hydrocarbons (PAHs), and have therefore received considerable attention. In this study, the physical (mass and number concentration, and size distribution) and chemical (PAHs) properties were investigated at a major bus interchange in Singapore, influenced only by diesel exhausts. Number concentration and size distribution of particles were determined in real time, while the mass concentrations of PM2.5, and PAHs were measured during operating and nonoperating hours. The average mass concentrations of PM2.5 and PAHs increased by a factor of 2.34 and 5.18, respectively, during operating hours. The average number concentration was also elevated by a factor of 5.07 during operating hours. This increase in the concentration of PM2.5 particles and their chemical constituents during operating hours was attributable to diesel emissions from in-use buses based on the particle size analysis, correlation among PAHs, and the commonly used PAHs diagnostic ratios. To evaluate the potential health threat due inhalation of air pollutants released from diesel engines, the incremental lifetime cancer risk was also calculated for a maximally exposed individual. The findings indicate that the air quality at the bus interchange poses adverse health effects.

Associations between toenail arsenic concentration and dietary factors in a New Hampshire population.

PubMed

Gruber, Joann F; Karagas, Margaret R; Gilbert-Diamond, Diane; Bagley, Pamela J; Zens, M Scot; Sayarath, Vicki; Punshon, Tracy; Morris, J Steven; Cottingham, Kathryn L

2012-06-29

Dietary factors such as folate, vitamin B12, protein, and methionine are important for the excretion of arsenic via one-carbon metabolism in undernourished populations exposed to high levels of arsenic via drinking water. However, the effects of dietary factors on toenail arsenic concentrations in well-nourished populations exposed to relatively low levels of water arsenic are unknown. As part of a population-based case-control study of skin and bladder cancer from the USA, we evaluated relationships between consumption of dietary factors and arsenic concentrations in toenail clippings. Consumption of each dietary factor was determined from a validated food frequency questionnaire. We used general linear models to examine the associations between toenail arsenic and each dietary factor, taking into account potentially confounding effects. As expected, we found an inverse association between ln-transformed toenail arsenic and consumption of vitamin B12 (excluding supplements) and animal protein. Unexpectedly, there were also inverse associations with numerous dietary lipids (e.g., total fat, total animal fat, total vegetable fat, total monounsaturated fat, total polyunsaturated fat, and total saturated fat). Finally, increased toenail arsenic concentrations were associated with increased consumption of long chain n-3 fatty acids. In a relatively well-nourished population exposed to relatively low levels of arsenic via water, consumption of certain dietary lipids may decrease toenail arsenic concentration, while long chain n-3 fatty acids may increase toenail arsenic concentration, possibly due to their association with arsenolipids in fish tissue.

Associations between toenail arsenic concentration and dietary factors in a New Hampshire population

PubMed Central

2012-01-01

Background Dietary factors such as folate, vitamin B12, protein, and methionine are important for the excretion of arsenic via one-carbon metabolism in undernourished populations exposed to high levels of arsenic via drinking water. However, the effects of dietary factors on toenail arsenic concentrations in well-nourished populations exposed to relatively low levels of water arsenic are unknown. Methods As part of a population-based case–control study of skin and bladder cancer from the USA, we evaluated relationships between consumption of dietary factors and arsenic concentrations in toenail clippings. Consumption of each dietary factor was determined from a validated food frequency questionnaire. We used general linear models to examine the associations between toenail arsenic and each dietary factor, taking into account potentially confounding effects. Results As expected, we found an inverse association between ln-transformed toenail arsenic and consumption of vitamin B12 (excluding supplements) and animal protein. Unexpectedly, there were also inverse associations with numerous dietary lipids (e.g., total fat, total animal fat, total vegetable fat, total monounsaturated fat, total polyunsaturated fat, and total saturated fat). Finally, increased toenail arsenic concentrations were associated with increased consumption of long chain n-3 fatty acids. Conclusion In a relatively well-nourished population exposed to relatively low levels of arsenic via water, consumption of certain dietary lipids may decrease toenail arsenic concentration, while long chain n-3 fatty acids may increase toenail arsenic concentration, possibly due to their association with arsenolipids in fish tissue. PMID:22747713

Natural variation of selenium in Brazil nuts and soils from the Amazon region.

PubMed

Silva Junior, E C; Wadt, L H O; Silva, K E; Lima, R M B; Batista, K D; Guedes, M C; Carvalho, G S; Carvalho, T S; Reis, A R; Lopes, G; Guilherme, L R G

2017-12-01

Brazil nut tree (Bertholletia excelsa) is native of the Amazon rainforest. Brazil nuts are consumed worldwide and are known as the richest food source of selenium (Se). Yet, the reasoning for such Se contents is not well stablished. We evaluated the variation in Se concentration of Brazil nuts from Brazilian Amazon basin, as well as soil properties, including total Se concentration, of the soils sampled directly underneath the trees crown, aiming to investigate which soil properties influence Se accumulation in the nuts. The median Se concentration in Brazil nuts varied from 2.07 mg kg - 1 (in Mato Grosso state) to 68.15 mg kg - 1 (in Amazonas state). Therefore, depending on its origin, a single Brazil nut could provide from 11% (in the Mato Grosso state) up to 288% (in the Amazonas state) of the daily Se requirement for an adult man (70 μg). The total Se concentration in the soil also varied considerably, ranging from <65.76 to 625.91 μg kg - 1 , with highest Se concentrations being observed in soil samples from the state of Amazonas. Se accumulation in Brazil nuts generally increased in soils with higher total Se content, but decreased under acidic conditions in the soil. This indicates that, besides total soil Se concentration, soil acidity plays a major role in Se uptake by Brazil nut trees, possibly due to the importance of this soil property to Se retention in the soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Composition and concentration of hydrocarbons in sediment samples from the oil producing area of the East Shetland Basin, Scotland.

PubMed

Russell, M; Webster, L; Walsham, P; Packer, G; Dalgarno, E J; McIntosh, A D; Fryer, R J; Moffat, C F

2008-04-01

The East Shetland Basin is one of the areas that the Fisheries Research Services (FRS) has concentrated on to assess the possible impacts of oil exploration and production on the marine environment. A stratified random survey of the sediment was carried out in 2002. TOCs were low across the basin and were positively correlated with grain size. The total PAH concentrations (2- to 6-ring parent and alkylated PAHs, including the 16 US EPA PAHs) were less than 150 microg kg(-1) dry weight and their composition indicated a predominantly pyrolytic input to the basin in 2002. Minor unresolved complex mixtures in the n-alkane profiles indicated a slight petrogenic input but further examination of the biomarkers (hopanes and steranes) showed a mixed North Sea and Middle Eastern source. The Middle Eastern source is likely due to inputs from shipping activity, as it is widely used as bunker fuel. Grid surveys were carried out in 1986, 1988-89 and 1994 and areas were selected for which there was data for all the historic grid surveys and the 2002 stratified random survey. Although referring to only a small part of the East Shetland Basin, comparison with these historic surveys shows clearly that the concentrations of Forties crude oil equivalents and total PAH concentrations were highest in 1988-89 and by 2002 had returned to concentrations the same as or less than observed in the original survey in 1986.

Effect of nitrate concentration on filamentous bulking under low level of dissolved oxygen in an airlift inner circular anoxic-aerobic incorporate reactor.

PubMed

Su, Yiming; Zhang, Yalei; Zhou, Xuefei; Jiang, Ming

2013-09-01

This laboratory research investigated a possible cause of filamentous bulking under low level of dissolved oxygen conditions (dissolved oxygen value in aerobic zone maintained between 0.6-0.8 mg O2/L) in an airlift inner-circular anoxic-aerobic reactor. During the operating period, it was observed that low nitrate concentrations affected sludge volume index significantly. Unlike the existing hypothesis, the batch tests indicated that filamentous bacteria (mainly Thiothrix sp.) could store nitrate temporarily under carbon restricted conditions. When nitrate concentration was below 4 mg/L, low levels of carbon substrates and dissolved oxygen in the aerobic zone stimulated the nitrate-storing capacity of filaments. When filamentous bacteria riched in nitrate reached the anoxic zone, where they were exposed to high levels of carbon but limited nitrate, they underwent denitrification. However, when nonfilamentous bacteria were exposed to similar conditions, denitrification was restrained due to their intrinsic nitrate limitation. Hence, in order to avoid filamentous bulking, the nitrate concentration in the return sludge (from aerobic zone to the anoxic zone) should be above 4 mg/L, or alternatively, the nitrate load in the anoxic zone should be kept at levels above 2.7 mg NO(3-)-N/g SS.

Composition of Metallic Elements and Size Distribution of Fine and Ultrafine Particles in a Steelmaking Factory.

PubMed

Marcias, Gabriele; Fostinelli, Jacopo; Catalani, Simona; Uras, Michele; Sanna, Andrea Maurizio; Avataneo, Giuseppe; De Palma, Giuseppe; Fabbri, Daniele; Paganelli, Matteo; Lecca, Luigi Isaia; Buonanno, Giorgio; Campagna, Marcello

2018-06-07

The characteristics of aerosol, in particular particle size and chemical composition, can have an impact on human health. Particle size distribution and chemical composition is a necessary parameter in occupational exposure assessment conducted in order to understand possible health effects. The aim of this study was to characterize workplace airborne particulate matter in a metallurgical setting by synergistically using two different approaches; Methodology: Analysis of inhalable fraction concentrations through traditional sampling equipment and ultrafine particles (UFP) concentrations and size distribution was conducted by an Electric Low-Pressure Impactor (ELPI+™). The determination of metallic elements (ME) in particles was carried out by inductively coupled plasma mass spectrometry; Results: Inhalable fraction and ME concentrations were below the limits set by Italian legislation and the American Conference of Governmental Industrial Hygienists (ACGIH, 2017). The median of UFP was between 4.00 × 10⁴ and 2.92 × 10⁵ particles/cm³. ME concentrations determined in the particles collected by ELPI show differences in size range distribution; Conclusions: The adopted synergistic approach enabled a qualitative and quantitative assessment of the particles in steelmaking factories. The results could lead to a better knowledge of occupational exposure characterization, in turn affording a better understanding of occupational health issues due to metal fumes exposure.

Performance Characteristics of the Electronic Snow Water Equivalent (SWE) Sensor in Arctic, Marine, and Humid Continental Climates

NASA Astrophysics Data System (ADS)

Johnson, J.; Gelvin, A. B.; Duvoy, P.; Schaefer, G. L.; Poole, G.; Horton, G. D.

2011-12-01

The USA ERDC CRREL and the USDA NRCS developed a 3-m square electronic SWE sensor (e-SWE sensor) consisting of nine perforated panels (a center panel to measure SWE and eight outer panels to buffer edge stress concentrations). Seven e-SWE sensors were installed in five different climate zones including north central and north coastal Alaska, Oregon, Newfoundland, and New York State. With the exception of New York State, the e-SWE sensors accurately measured SWE. The e-SWE sensor at Hogg Pass, OR, accurately measured SWE during five years of observations even when edge stress concentrations occurred. In windy conditions of northern Alaska, the sensor measured losses and gains in SWE with more reliability and higher accuracy than other standard methods. The sensor also detected snowdrift migration (comparing video and sensor measurements). In the thin, icy snow of New York the electronic SWE sensors over-measured SWE during midwinter. Over-measurement errors were caused by edge stress concentrations associated with strong icy layers, a shallow snow cover and possibly using a backfill material with different thermal properties and a large freeboard compared to the surrounding soil . Measurement accuracy improved in spring due to increased snow creep, associated with warming snow temperatures, which reduced edge stress concentrations.

Sex differences in oxidative stress after eccentric and concentric exercise.

PubMed

Wiecek, Magdalena; Maciejczyk, Marcin; Szymura, Jadwiga; Szygula, Zbigniew

2017-11-01

Comparison of redox balance changes in the blood of women and men as a result of submaximal eccentric (ECC) and concentric (CONC) efforts. 10 women and 10 men performed three 45-minute submaximal treadmill runs at constant velocities (downhill run - ECC, uphill run - CONC and level run). Prior to the 45-minute exercises, after their completion and following 24 hours of recovery, the concentration of lactate, oxidized low-density lipoprotein (ox-LDL), 3-nitrotyrosine, uric acid (UA) and the white blood cell count (WBC), neutrophil (NEUT), lymphocyte (LYMPH) and monocyte content in the blood were determined. In women, the ox-LDL increased significantly 10 minutes and 24 hours following ECC (P < 0.05). 10 minutes after ECC, in women, there was an increase in WBC, NEUT and LYMPH (P < 0.05). In the men, WBC and NEUT increased significantly 24 hours after CONC and ECC (P < 0.05). UA in each determination was higher in the men than the women (P < 0.05). ECC cause impaired redox balance only in women. Due to the increase in antioxidant capacity of the blood without accompanying oxidative damage to macromolecules, for both sexes, it is recommended to perform concentric running efforts at the highest possible subliminal intensity.

Neuroprotection by Cocktails of Dietary Antioxidants under Conditions of Nerve Growth Factor Deprivation

PubMed Central

Amara, Flavio; Berbenni, Miluscia; Fragni, Martina; Leoni, Giampaolo; Viggiani, Sandra; Ippolito, Vita Maria; Larocca, Marilena; Rossano, Rocco; Alberghina, Lilia; Riccio, Paolo; Colangelo, Anna Maria

2015-01-01

Dietary antioxidants may be useful in counteracting the chronic inflammatory status in neurodegenerative diseases by reducing oxidative stress due to accumulation of reactive oxygen species (ROS). In this study, we newly described the efficacy of a number of dietary antioxidants (polyphenols, carotenoids, thiolic compounds, and oligoelements) on viability of neuronal PC12 cells following Nerve Growth Factor (NGF) deprivation, a model of age-related decrease of neurotrophic support that triggers neuronal loss. Neuroprotection by antioxidants during NGF deprivation for 24 h was largely dependent on their concentrations: all dietary antioxidants were able to efficiently support cell viability by reducing ROS levels and restoring mitochondrial function, while preserving the neuronal morphology. Moreover, ROS reduction and neuroprotection during NGF withdrawal were also achieved with defined cocktails of 3–6 different antioxidants at concentrations 5–60 times lower than those used in single treatments, suggesting that their antioxidant activity was preserved also at very low concentrations. Overall, these data indicate the beneficial effects of antioxidants against oxidative stress induced by decreased NGF availability and suggest that defined cocktails of dietary factors at low concentrations might be a suitable strategy to reduce oxidative damage in neurodegenerative diseases, while limiting possible side effects. PMID:26236423

Significant reduction in indoor radon in newly built houses.

PubMed

Finne, Ingvild E; Kolstad, Trine; Larsson, Maria; Olsen, Bård; Prendergast, Josephine; Rudjord, Anne Liv

2018-02-15

Results from two national surveys of radon in newly built homes in Norway, performed in 2008 and 2016, were used in this study to investigate the effect of the 2010 building regulations introducing limit values on radon and requirements for radon prevention measures upon construction of new buildings. In both surveys, homes were randomly selected from the National Building Registry. The overall result was a considerable reduction of radon concentrations after the implementation of new regulations, but the results varied between the different dwelling categories. A statistically significant reduction was found for detached houses where the average radon concentration was almost halved from 76 to 40 Bq/m 3 . The fraction of detached houses which had at least one frequently occupied room with a radon concentration above the Action Level (100 Bq/m 3 ) fell from 23.9% to 6.4%, while the fraction above the Upper Limit Value (200 Bq/m 3 ) was reduced from 7.6% to 2.5%. In 2008 the average radon concentration measured in terraced and semi-detached houses was 44 and in 2016 it was 29 Bq/m 3 , but the reduction was not statistically significant. For multifamily houses, it was not possible to draw a conclusion due to insufficient number of measurements. Copyright © 2018 Elsevier Ltd. All rights reserved.

Concentric Tube Robots as Steerable Needles: Achieving Follow-the-Leader Deployment

PubMed Central

Gilbert, Hunter B.; Neimat, Joseph; Webster, Robert J.

2015-01-01

Concentric tube robots can enable new clinical interventions if they are able to pass through soft tissue, deploy along desired paths through open cavities, or travel along winding lumens. These behaviors require the robot to deploy in such a way that the curved shape of its shaft remains unchanged as the tip progresses forward (i.e., “follow-the-leader” deployment). Follow-the-leader deployment is challenging for concentric tube robots due to elastic (and particularly torsional) coupling between the tubes that form the robot. However, as we show in this paper, follow-the-leader deployment is possible, provided that tube precurvatures and deployment sequences are appropriately selected. We begin by defining follow-the-leader deployment and providing conditions that must be satisfied for a concentric tube robot to achieve it. We then examine several useful special cases of follow-the-leader deployment, showing that both circular and helical precurvatures can be employed, and provide an experimental illustration of the helical case. We also explore approximate follow-the-leader behavior and provide a metric for the similarity of a general deployment to a follow-the-leader deployment. Finally, we consider access to the hippocampus in the brain to treat epilepsy, as a motivating clinical example for follow-the-leader deployment. PMID:26622208

Surfactant-adsorption-induced initial depinning behavior in evaporating water and nanofluid sessile droplets.

PubMed

Zhong, Xin; Duan, Fei

2015-05-19

A surfactant-induced autophobic effect has been observed to initiate an intense depinning behavior at the initial stage of evaporation in both pure water and nanofluid sessile droplets. The cationic surfactant adsorbing to the negatively charged silicon wafer makes the solid surface more hydrophobic. The autophobing-induced depinning behavior, leading to an enlarged contact angle and a shortened base diameter, takes place only when the surfactant concentration is below its critical micelle concentration (cmc). The initial spreading degree right before the droplet retraction, the retracting velocity of the contact line, and the duration of the initial droplet retraction are shown to depend negatively on the surfactant concentration below the cmc. An unexpected enhancement in the initial depinning has been found in the nanofluid droplets, possibly resulting from the hydrophilic interplay between the graphite nanoparticle deposition and the surfactant molecules. Such promotion of the initial depinning due to the nanoparticle deposition makes the droplet retract even at a surfactant concentration higher than the cmc (1.5 cmc). The resulting deposition formed in the presence of the depinning behavior has great enhancement for coffee-ring formation as compared to the one free of surfactant, implying that the formation of a coffee ring does not require the pinning of the contact line during the entire drying process.

Levels and Sources of Volatile Organic Compounds in Homes of Children with Asthma

PubMed Central

Chin, Jo-Yu; Godwin, Christopher; Parker, Edith; Robins, Thomas; Lewis, Toby; Harbin, Paul; Batterman, Stuart

2014-01-01

Many volatile organic compounds (VOCs) are classified as known or possible carcinogens, irritants and toxicants, and VOC exposure has been associated with the onset and exacerbation of asthma. This study characterizes VOC levels in 126 homes of children with asthma in Detroit, Michigan, USA. The total target VOC concentration ranged from 14 to 2,274 μg/m3 (mean = 150 μg/m3; median = 91 μg/m3); 56 VOCs were quantified; and d-limonene, toluene, p, m-xylene and ethyl acetate had the highest concentrations. Based on the potential for adverse health effects, priority VOCs included naphthalene, benzene, 1,4-dichlorobenzene, isopropylbenzene, ethylbenzene, styrene, chloroform, 1,2-dichloroethane, tetrachloroethene and trichloroethylene. Concentrations varied mostly due to between-residence and seasonal variation. Identified emission sources included cigarette smoking, solvent-related emissions, renovations, household products and pesticides. The effect of nearby traffic on indoor VOC levels was not distinguished. While concentrations in the Detroit homes were lower than levels found in other North American studies, many homes had elevated VOC levels, including compounds that are known health hazards. Thus, the identification and control of VOC sources is important and prudent, especially for vulnerable individuals. Actions and policies to reduce VOC exposures, e.g., sales restrictions, improved product labeling and consumer education, are recommended. PMID:24329990

Concentric Tube Robots as Steerable Needles: Achieving Follow-the-Leader Deployment.

PubMed

Gilbert, Hunter B; Neimat, Joseph; Webster, Robert J

2015-04-01

Concentric tube robots can enable new clinical interventions if they are able to pass through soft tissue, deploy along desired paths through open cavities, or travel along winding lumens. These behaviors require the robot to deploy in such a way that the curved shape of its shaft remains unchanged as the tip progresses forward (i.e., "follow-the-leader" deployment). Follow-the-leader deployment is challenging for concentric tube robots due to elastic (and particularly torsional) coupling between the tubes that form the robot. However, as we show in this paper, follow-the-leader deployment is possible, provided that tube precurvatures and deployment sequences are appropriately selected. We begin by defining follow-the-leader deployment and providing conditions that must be satisfied for a concentric tube robot to achieve it. We then examine several useful special cases of follow-the-leader deployment, showing that both circular and helical precurvatures can be employed, and provide an experimental illustration of the helical case. We also explore approximate follow-the-leader behavior and provide a metric for the similarity of a general deployment to a follow-the-leader deployment. Finally, we consider access to the hippocampus in the brain to treat epilepsy, as a motivating clinical example for follow-the-leader deployment.

Electrochemical removal of phenol from oil refinery wastewater.

PubMed

Abdelwahab, O; Amin, N K; El-Ashtoukhy, E-S Z

2009-04-30

This study explores the possibility of using electrocoagulation to remove phenol from oil refinery waste effluent using a cell with horizontally oriented aluminum cathode and a horizontal aluminum screen anode. The removal of phenol was investigated in terms of various parameters namely: pH, operating time, current density, initial phenol concentration and addition of NaCl. Removal of phenol during electrocoagulation was due to combined effect of sweep coagulation and adsorption. The results showed that, at high current density and solution pH 7, remarkable removal of 97% of phenol after 2h can be achieved. The rate of electrocoagulation was observed to increase as the phenol concentration decreases; the maximum removal rate was attained at 30 mg L(-1) phenol concentration. For a given current density using an array of closely packed Al screens as anode was found to be more effective than single screen anode, the percentage phenol removal was found to increase with increasing the number of screens per array. After 2h of electrocoagulation, 94.5% of initial phenol concentration was removed from the petroleum refinery wastewater. Energy consumption and aluminum Electrode consumption were calculated per gram of phenol removed. The present study shows that, electrocoagulation of phenol using aluminum electrodes is a promising process.

Iris structure and minor physical anomalies in schizophrenia.

PubMed

Trixler, Dániel; Tényi, Tamás

2017-10-01

This study compared five human iris characteristics and minor physical anomalies (MPAs) between patients with schizophrenia (n = 32) and controls (n = 31). Correlations between iris characteristics and MPAs were expected, due to their same ectodermic origin. Iris macro photos were taken and quantified in five categories mentioned before. MPAs were also examined in both groups. Our results show significant differences in the frequency of pigment dots of the iris and total number of MPAs between groups. Other significant differences were found in the extension of concentric furrows, as they were more common in healthy subjects, while Wolfflin nodules occurred significantly more often in patients with schizophrenia. Expected difference in Fuch's crypts could not be observed between groups. Light eye color was positively correlated to pigment dots and Wolfflin nodules, and negatively correlated with concentric furrows. Dark eye color showed positive correlation with concentric furrows, and negative correlation with pigment dots and concentric furrows. A gender effect could also been observed: male individuals showed moderate positive correlations between pigment dots and total MPAs frequency, while this couldn't be observed in the female group. Our findings suggest possible connections between iris characteristics and MPAs, where males are more prone to deviations. Copyright © 2017 Elsevier B.V. All rights reserved.

Attractive interactions between reverse aggregates and phase separation in concentrated malonamide extractant solutions

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

Erlinger, C.; Belloni, L.; Zemb, T.

1999-03-30

Using small angle X-ray scattering, conductivity, and phase behavior determination, the authors show that concentrated solutions of malonamide extractants, dimethyldibutyltetradecylmalonamide (DMDBTDMA), are organized in reverse oligomeric aggregates which have many features in common with reverse micelles. The aggregation numbers of these reverse globular aggregates as well as their interaction potential are determined from absolute scattering curves. An attractive interaction is responsible for the demixing of the oil phase when in equilibrium with excess oil. Prediction of conductivity as well as the formation conditions for the third phase is possible using standard liquid theory applied to the extractant aggregates. The interactions,more » modeled with the sticky sphere model proposed by Baster, are shown to be due to steric interactions resulting from the hydrophobic tails of the extractant molecule and van der Waals forces between the highly polarizable water core of the reverse micelles. The attractive interaction in the oil phase, equilibrated with water, is determined as a function of temperature, extractant molecule concentration, and proton and neodynium(III) cation concentration. It is shown that van der Waals interactions, with an effective Hamaker constant of 3kT, quantitatively explain the behavior of DMDBTDMA in n-dodecane in terms of scattering as well as phase stability limits.« less

A baseline study of metals in herring (Clupea harengus) from the Norwegian Sea, with focus on mercury, cadmium, arsenic and lead.

PubMed

Frantzen, Sylvia; Maage, Amund; Duinker, Arne; Julshamn, Kaare; Iversen, Svein A

2015-05-01

The Norwegian spring spawning (NSS) herring is an ecologically and economically important fish population in the Norwegian Sea. It was the first of several Norwegian fish stocks subject to a baseline study designed to give a comprehensive account of the levels of contaminants in a fish species from most of its area of distribution and during different seasons. During 2006 and 2007, 800 individual herring were sampled in their feeding areas in the Norwegian Sea in spring and autumn and at their spawning grounds off the coast of Norway during late winter. Metals including Hg, Cd, As and Pb were determined in muscle samples of individual herring, and mean concentrations±sd (mg kg(-1) ww) were: Hg: 0.04±0.03, Cd: 0.010±0.006, As: 2.2±0.6 and Pb: <0.01-0.10. Apart from one sample, no individual herring exceeded the EU's maximum level for any of these elements, as has been seen also in previous monitoring. Hg and Cd concentration increased with increasing fish age and As concentration varied seasonally, possibly due to uptake during feeding (summer), elimination during starvation (winter) and up-concentration during spawning (spring). Copyright © 2015 Elsevier Ltd. All rights reserved.

Uncertainties in monitoring of SVOCs in air caused by within-sampler degradation during active and passive air sampling

NASA Astrophysics Data System (ADS)

Melymuk, Lisa; Bohlin-Nizzetto, Pernilla; Prokeš, Roman; Kukučka, Petr; Přibylová, Petra; Vojta, Šimon; Kohoutek, Jiří; Lammel, Gerhard; Klánová, Jana

2017-10-01

Degradation of semivolatile organic compounds (SVOCs) occurs naturally in ambient air due to reactions with reactive trace gases (e.g., ozone, NOx). During air sampling there is also the possibility for degradation of SVOCs within the air sampler, leading to underestimates of ambient air concentrations. We investigated the possibility of this sampling artifact in commonly used active and passive air samplers for seven classes of SVOCs, including persistent organic pollutants (POPs) typically covered by air monitoring programs, as well as SVOCs of emerging concern. Two active air samplers were used, one equipped with an ozone denuder and one without, to compare relative differences in mass of collected compounds. Two sets of passive samplers were also deployed to determine the influence of degradation during longer deployment times in passive sampling. In active air samplers, comparison of the two sampling configurations suggested degradation of particle-bound polycyclic aromatic hydrocarbons (PAHs), with concentrations up to 2× higher in the denuder-equipped sampler, while halogenated POPs did not have clear evidence of degradation. In contrast, more polar, reactive compounds (e.g., organophosphate esters and current use pesticides) had evidence of losses in the sampler with denuder. This may be caused by the denuder itself, suggesting sampling bias for these compounds can be created when typical air sampling apparatuses are adapted to limit degradation. Passive air samplers recorded up to 4× higher concentrations when deployed for shorter consecutive sampling periods, suggesting that within-sampler degradation may also be relevant in passive air monitoring programs.

Highly sensitive avoidance plays a key role in sensory adaptation to deep-sea hydrothermal vent environments.

PubMed

Ogino, Tetsuya; Maegawa, Shingo; Shigeno, Shuichi; Fujikura, Katsunori; Toyohara, Haruhiko

2018-01-01

The environments around deep-sea hydrothermal vents are very harsh conditions for organisms due to the possibility of exposure to highly toxic compounds and extremely hot venting there. Despite such extreme environments, some indigenous species have thrived there. Alvinellid worms (Annelida) are among the organisms best adapted to high-temperature and oxidatively stressful venting regions. Although intensive studies of the adaptation of these worms to the environments of hydrothermal vents have been made, little is known about the worms' sensory adaptation to the severe chemical conditions there. To examine the sensitivity of the vent-endemic worm Paralvinella hessleri to low pH and oxidative stress, we determined the concentration of acetic acid and hydrogen peroxide that induced avoidance behavior of this worm, and compared these concentrations to those obtained for related species inhabiting intertidal zones, Thelepus sp. The concentrations of the chemicals that induced avoidance behavior of P. hessleri were 10-100 times lower than those for Thelepus sp. To identify the receptors for these chemicals, chemical avoidance tests were performed with the addition of ruthenium red, a blocker of transient receptor potential (TRP) channels. This treatment suppressed the chemical avoidance behavior of P. hessleri, which suggests that TRP channels are involved in the chemical avoidance behavior of this species. Our results revealed for the first time hypersensitive detection systems for acid and for oxidative stress in the vent-endemic worm P. hessleri, possibly mediated by TRP channels, suggesting that such sensory systems may have facilitated the adaptation of this organism to harsh vent environments.

Secretin stimulates HCO3(-) and acetate efflux but not Na+/HCO3(-) uptake in rat pancreatic ducts.

PubMed

Novak, I; Christoffersen, B C

2001-03-01

Pancreatic ducts secrete HCO3(-), but transport mechanisms are unresolved and possibly vary between species. Our aim was to study the intracellular pH (pHi) regulation and thus H+/HCO3- transport in rat pancreatic ducts. Of particular interest was the Na+/HCO3(-) cotransporter, thought to be important in HCO3(-) -transporting epithelia. pHi was measured with BCECF in freshly isolated intralobular ducts. A reduction in extracellular Na+ concentration or application of HOE 694 (1 microM) decreased pHi by 0.1 to 0.6 pH units, demonstrating Na+/H+ exchanger activity. A reduction in extracellular Cl- concentration or addition of H2DIDS (10 microM) increased pHi by 0.1 to 0.5 pH units, demonstrating Cl-/ HCO(3)- (OH ) exchanger activity. In experimental acidosis, extracellular HCO3(-)/CO2 buffer did not increase the rate of pHi recovery, indicating that provision of HCO3(-) by the Na+/HCO3(-) cotransporter was not apparent. Most importantly, Na+/HCO3(-) cotransport was not stimulated by secretin (1 nM). In contrast, in experimental alkalosis the pHi recovery was increased in HCO3(-)/CO2 buffer, possibly due to Na+/HCO3(-) cotransport in the efflux mode. Secretin (1 nM) and carbachol (1 microM) stimulated HCO3(-) efflux, which can account for the observed HCO3(-) concentrations in rat pancreatic juice. Acetate and HCO3(-) buffers were handled similarly, indicating similar transport mechanisms in pancreatic ducts.

3D printing of concentrated emulsions into multiphase biocompatible soft materials.

PubMed

Sommer, Marianne R; Alison, Lauriane; Minas, Clara; Tervoort, Elena; Rühs, Patrick A; Studart, André R

2017-03-01

3D printing via direct ink writing (DIW) is a versatile additive manufacturing approach applicable to a variety of materials ranging from ceramics over composites to hydrogels. Due to the mild processing conditions compared to other additive manufacturing methods, DIW enables the incorporation of sensitive compounds such as proteins or drugs into the printed structure. Although emulsified oil-in-water systems are commonly used vehicles for such compounds in biomedical, pharmaceutical, and cosmetic applications, printing of such emulsions into architectured soft materials has not been fully exploited and would open new possibilities for the controlled delivery of sensitive compounds. Here, we 3D print concentrated emulsions into soft materials, whose multiphase architecture allows for site-specific incorporation of both hydrophobic and hydrophilic compounds into the same structure. As a model ink, concentrated emulsions stabilized by chitosan-modified silica nanoparticles are studied, because they are sufficiently stable against coalescence during the centrifugation step needed to create a bridging network of droplets. The resulting ink is ideal for 3D printing as it displays high yield stress, storage modulus and elastic recovery, through the formation of networks of droplets as well as of gelled silica nanoparticles in the presence of chitosan. To demonstrate possible architectures, we print biocompatible soft materials with tunable hierarchical porosity containing an encapsulated hydrophobic compound positioned in specific locations of the structure. The proposed emulsion-based ink system offers great flexibility in terms of 3D shaping and local compositional control, and can potentially help address current challenges involving the delivery of incompatible compounds in biomedical applications.

The oxygen-centered radicals scavenging activity of sulfasalazine and its metabolites. A direct protection of the bowel.

PubMed

Prónai, L; Yukinobu, I; Láng, I; Fehér, J

1992-01-01

Oxygen-centered radicals, such as superoxide (O2-) and hydroxyl radicals (.OH) generated by phagocytes have been suggested to be involved in the pathogenesis of chronic inflammations of the bowel, such as Crohn's disease and colitis ulcerosa. Recently, sulfasalazine (SASP) and its metabolites have been reported to exert their effects as a direct scavenger of oxygen-centered radicals in the bowel. To scavenge oxygen-centered radicals in vivo, however, SASP and its metabolites have to react with O2- and/or .OH in vitro very rapidly, furthermore they have to reach an appropriate (possible millimolar) concentration range at the site of inflammation. To test this possibility, we investigated the direct O2- and .OH scavenging activity of SASP and its metabolites using the specific electron paramagnetic resonance/spin trapping method, and we compared the 50% inhibition rates of SASP and its metabolites with their known concentrations in the bowel and in the human plasma. It was found that SASP and its metabolites, such as 5-amino-salicylic acid (5-ASA), and acetyl-5-amino-salicylic acid (AC-5-ASA), but not sulfapyridine (SP) and acetyl-sulfapyridine (Ac-SP) have a direct O2- and .OH scavenging activity in vitro systems. Among the compounds, SASP and 5-ASA can reach a concentration which is appropriate to scavenge oxygen-centered radicals in the bowel but not in the human plasma. It was concluded that the in vivo antiinflammatory effects of SASP and its metabolites are, at least partly, due to the direct oxygen-centered scavenging activity of these drugs.

Estimation of time-varying growth, uptake and excretion rates from dynamic metabolomics data.

PubMed

Cinquemani, Eugenio; Laroute, Valérie; Cocaign-Bousquet, Muriel; de Jong, Hidde; Ropers, Delphine

2017-07-15

Technological advances in metabolomics have made it possible to monitor the concentration of extracellular metabolites over time. From these data, it is possible to compute the rates of uptake and excretion of the metabolites by a growing cell population, providing precious information on the functioning of intracellular metabolism. The computation of the rate of these exchange reactions, however, is difficult to achieve in practice for a number of reasons, notably noisy measurements, correlations between the concentration profiles of the different extracellular metabolites, and discontinuties in the profiles due to sudden changes in metabolic regime. We present a method for precisely estimating time-varying uptake and excretion rates from time-series measurements of extracellular metabolite concentrations, specifically addressing all of the above issues. The estimation problem is formulated in a regularized Bayesian framework and solved by a combination of extended Kalman filtering and smoothing. The method is shown to improve upon methods based on spline smoothing of the data. Moreover, when applied to two actual datasets, the method recovers known features of overflow metabolism in Escherichia coli and Lactococcus lactis , and provides evidence for acetate uptake by L. lactis after glucose exhaustion. The results raise interesting perspectives for further work on rate estimation from measurements of intracellular metabolites. The Matlab code for the estimation method is available for download at https://team.inria.fr/ibis/rate-estimation-software/ , together with the datasets. eugenio.cinquemani@inria.fr. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Transcriptional analysis of product-concentration driven changes in cellular programs of recombinant Clostridium acetobutylicumstrains.

PubMed

Tummala, Seshu B; Junne, Stefan G; Paredes, Carlos J; Papoutsakis, Eleftherios T

2003-12-30

Antisense RNA (asRNA) downregulation alters protein expression without changing the regulation of gene expression. Downregulation of primary metabolic enzymes possibly combined with overexpression of other metabolic enzymes may result in profound changes in product formation, and this may alter the large-scale transcriptional program of the cells. DNA-array based large-scale transcriptional analysis has the potential to elucidate factors that control cellular fluxes even in the absence of proteome data. These themes are explored in the study of large-scale transcriptional analysis programs and the in vivo primary-metabolism fluxes of several related recombinant C. acetobutylicum strains: C. acetobutylicum ATCC 824(pSOS95del) (plasmid control; produces high levels of butanol snd acetone), 824(pCTFB1AS) (expresses antisense RNA against CoA transferase (ctfb1-asRNA); produces very low levels of butanol and acetone), and 824(pAADB1) (expresses ctfb1-asRNA and the alcohol-aldehyde dahydrogenase gene (aad); produce high alcohol and low acetone levels). DNA-array based transcriptional analysis revealed that the large changes in product concentrations (snd notably butanol concentration) due to ctfb1-asRNA expression alone and in combination with aad overexpression resulted in dramatic changes of the cellular transcriptome. Cluster analysis and gene expression patterns of established and putative operons involved in stress response, motility, sporulation, and fatty-acid biosynthesis indicate that these simple genetic changes dramatically alter the cellular programs of C. acetobutylicum. Comparison of gene expression and flux analysis data may point to possible flux-controling steps and suggest unknown regulatory mechanisms. Copyright 2003; Wiley Periodicals, Inc.

Relations among rainstorm runoff, streamflow, pH, and metal concentrations, Summitville Mine area, upper Alamosa River basin, southwest Colorado, 1995-97

USGS Publications Warehouse

Rupert, Michael G.

2001-01-01

The upper Alamosa River Basin contains areas that are geochemically altered and have associated secondary sulfide mineralization. Occurring with this sulfide mineralization are copper, gold, and silver deposits that have been mined since the 1870's. Weathering of areas with sulfide mineralization produces runoff with anomalously low pH and high metal concentrations; mining activities exacerbate the condition. Summer rainstorms in the upper Alamosa River Basin produce a characteristic relation between streamflow and pH; streamflow suddenly increases and pH suddenly decreases (commonly by more than 1 pH unit). This report evaluates changes in pH in the upper Alamosa River Basin during July, August, and September 1995, 1996, and 1997 to examine possible adverse environmental effects due to rainstorm runoff. Ninety-three percent of the rainstorms occurring during 1995?97 produced runoff throughout the entire basin. Out of 54 storms, only 3 storms were isolated to the river reach upstream from the streamflow-gaging station Alamosa River above Wightman Fork, and only 1 storm was isolated to the river reach between the streamflow-gaging stations Alamosa River below Jasper and Alamosa River above Terrace Reservoir. Although most rainstorm runoff events occurred throughout the entire basin, pH changes were highest in parts of the basin that receive runoff from hydrothermally altered areas. The three principal altered areas within the basin are the Jasper, Stunner, and Summitville areas. Only limited mining occurred in the Stunner altered area, and yet significant decreases in pH values occur due to runoff from this area. Even after environmental restoration activities are completed at the Summitville Mine, the main stem of the Alamosa River may continue to be adversely affected by runoff from the Stunner and Jasper altered areas. A comparison of measured pH with Federal and State of Colorado water-quality standards and Toxicological Reference Values indicates pH was too low to support aquatic life in many parts of the basin for extended periods of time. Added stresses from sudden decreases in pH due to rainstorm runoff compound the adverse effects. Discharge of effluent from the Summitville Mine impoundment can significantly decrease pH in the Alamosa River downstream to Terrace Reservoir. A release of only 3 cubic feet per second from the impoundment decreased pH by at least 1 standard unit at all downstream sites. Low-flow years may pose a substantial risk to aquatic organisms within and downstream from Terrace Reservoir. During 1996, the basin had a low-flow year, and water storage and pool size of Terrace Reservoir were significantly reduced. The pH of water discharging from Terrace Reservoir was anomalously low during late August and September 1996, possibly due to geochemical interactions between sediment and the water column within the reservoir. In general, an inverse log-log relation exists between pH and the logarithm of dissolved metal concentrations, but the relations generally are not significant enough to confidently predict metal concentrations based upon measured pH values.

Citric acid assisted phytoextraction of chromium by sunflower; morpho-physiological and biochemical alterations in plants.

PubMed

Farid, Mujahid; Ali, Shafaqat; Rizwan, Muhammad; Ali, Qasim; Abbas, Farhat; Bukhari, Syed Asad Hussain; Saeed, Rashid; Wu, Longhua

2017-11-01

Soil and water contamination from heavy metals and metalloids is one of the most discussed and burning global issues due to its potential to cause the scarcity of healthy food and safe water. The scientific community is proposing a range of lab and field based physical, chemical and biological solutions to remedy metals and metalloids contaminated soils and water. The present study finds out a possibility of Chromium (Cr) extraction by sunflower from spiked soil under chelating role of citric acid (CA). The sunflower plants were grown under different concentrations of Cr (0, 5, 10 & 20mgkg -1 ) and CA (0, 2.5 & 5mM). Growth, biomass, gas exchange, photosynthesis, electrolyte leakage (EL), reactive oxygen species (ROS; malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ) and the activities of antioxidant enzymes such as, superoxide dismutase (SOD), guaiacole values peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT) were measured. The results depicted a clear decline in plant height, root length, leaf area, number of leaves and flowers per plant along with fresh and dry biomass of all parts of plant with increasing concentration of Cr in soil. Similar reduction was observed in chlorophyll a and b, total chlorophyll, carotenoids, soluble protein, gas exchange attributes and SPAD. The increasing concentration of Cr also enhanced the Cr uptake and accumulation in plant roots, stem and leaves along with the production of ROS and EL. The activities of antioxidant enzymes increased with increasing Cr concentration from 0 to 10mg, but decreased at 20mgkg -1 soil. The CA application significantly alleviated Cr-induced inhibition of plant growth, biomass, photosynthesis, gas exchange, soluble proteins and SPAD value. Presence of CA also enhanced the activities of all antioxidant enzymes and reduced the production of ROS and EL. The chelating potential of CA increased the concentration and accumulation of Cr in plant roots, stem and leaves. It is concluded that the sunflower can be a potential candidate for the remediation of Cr under CA treatment, while the possibility may vary with genotype, Cr level and CA concentration. Copyright © 2017 Elsevier Inc. All rights reserved.

Persistence of perfluoroalkylated substances in closed bottle tests with municipal sewage sludge.

PubMed

Sáez, Monica; de Voogt, Pim; Parsons, John R

2008-09-01

Perfluoroalkylated substances (PFAS) are chemicals with completely fluorinated alkyl chains. The specific properties of the F-C bond give PFAS a high stability and make them very useful in a wide range of applications. PFAS also pose a potential risk to the environment and humans because they have been recently characterized as persistent, bioaccumulative, and toxic. The objective of this work is to study the bacterial degradation of PFAS under aerobic and anaerobic conditions in municipal sewage sludge as a contribution toward understanding their environmental fate and behavior. Bacterial communities from sewage sludge were exposed to a mixture of PFAS under aerobic or anaerobic conditions. Individual PFAS concentrations were determined in the experiment media at different exposure times using liquid chromatography-mass spectrometry analysis after extraction with solid-phase extraction. The PFAS analyses of samples of sludge showed repeatable replicate results, allowing a reliable quantification of the different groups of PFAS analyzed. No conclusive evidence for PFAS degradation was observed under the experimental conditions tested in this work. Reduction in concentrations, however, was observed for some PFAS in sludge under aerobic conditions. The largest concentration decrease occurred for the fluorotelomer alcohols (FTOHs), especially for the 8:2 FTOH, which have been described as biodegradable in the literature. However, this concentration decrease could be due to different causes: sorption to glass, septa, or matrix components, as well as bacterial activity. Therefore, it is not certain that biodegradation occurred. PFAS are very recalcitrant chemicals, especially when fully fluorinated. Although some decreases in concentration have been observed for some PFAS, such as the FTOHs, there is no conclusive evidence for biodegradation. It can be concluded that the PFAS tested in these experiments are non-biodegradable under these experimental conditions. Since the presence of PFAS is ubiquitous in the environment and they can be toxic, more research is needed in this field to elucidate which PFAS are susceptible to biodegradation, the conditions required for biodegradation, and the possible routes followed. A possible inhibitory effect of PFAS on bacteria, the threshold concentrations, and conditions of inhibition should also be investigated.

Developmental Strategy For Effective Sampling To Detect Possible Nutrient Fluxes In Oligotrophic Coastal Reef Waters In The Caribbean

NASA Astrophysics Data System (ADS)

Mendoza, W. G.; Corredor, J. E.; Ko, D.; Zika, R. G.; Mooers, C. N.

2008-05-01

The increasing effort to develop the coastal ocean observing system (COOS) in various institutions has gained momentum due to its high value to climate, environmental, economic, and health issues. The stress contributed by nutrients to the coral reef ecosystem is among many problems that are targeted to be resolved using this system. Traditional nutrient sampling has been inadequate to resolve issues on episodic nutrient fluxes in reef regions due to temporal and spatial variability. This paper illustrates sampling strategy using the COOS information to identify areas that need critical investigation. The area investigated is within the Puerto Rico subdomain (60-70oW, 15-20oN), and Caribbean Time Series (CaTS), World Ocean Circulation Experiment (WOCE), Intra-America Sea (IAS) ocean nowcast/forecast system (IASNFS), and other COOS-related online datasets are utilized. Nutrient profile results indicate nitrate is undetectable in the upper 50 m apparently due to high biological consumption. Nutrients are delivered in Puerto Rico particularly in the CaTS station either via a meridional jet formed from opposing cyclonic and anticyclonic eddies or wind-driven upwelling. The strong vertical fluctuation in the upper 50 m demonstrates a high anomaly in temperature and salinity and a strong cross correlation signal. High chlorophyll a concentration corresponding to seasonal high nutrient influx coincides with higher precipitation accumulation rates and apparent riverine input from the Amazon and Orinoco Rivers during summer (August) than during winter (February) seasons. Non-detectability of nutrients in the upper 50 m is a reflection of poor sampling frequency or the absence of a highly sensitive nutrient analysis method to capture episodic events. Thus, this paper was able to determine the range of depths and concentrations that need to be critically investigated to determine nutrient fluxes, nutrient sources, and climatological factors that can affect nutrient delivery. It also provides some insight into needed sampling rates and temporal and spatial domain choices. Finally, it demonstrates a scientific reconnaissance for a field study that is now possible with online in-situ and remote sensing observations and numerical simulations, as a consequence of IOOS in general and COOS in particular.

Potential impacts of climate change on carbon dynamics in a rain-fed agro-ecosystem on the Loess Plateau of China.

PubMed

Qiu, Linjing; Hao, Mingde; Wu, Yiping

2017-01-15

Although many studies have been conducted on crop yield in rain-fed agriculture, the possible impacts of climate change on the carbon (C) dynamics of rain-fed rotation systems, particularly their direction and magnitude at the long-term scale, are still poorly understood. In this study, the sensitivity of C dynamics of a typical rotation system to elevated CO 2 and changed temperature and precipitation were first tested using the CENTURY model, based on data collected from a 30-year field experiment of a corn-wheat-wheat-millet (CWWM) rotation system in the tableland of the Loess Plateau. The possible responses of crop biomass C and soil organic C (SOC) accumulation were then evaluated under scenarios representing the Representative Concentration Pathways (RCPs) 4.5 and 8.5. The results indicated that elevated CO 2 and increased precipitation exerted positive effect on biomass C in CWWM rotation system, while increasing the temperature by 1°C, 2°C and 4°C had negative effects on biomass C due to opposite responses of corn and winter wheat to warming. SOC accumulation was enhanced by increased CO 2 concentration and precipitation but impaired by increased temperature. Under future RCP scenarios with dynamic CO 2 , the biomass C of corn exhibited decrease during the period of 2046-2075 under RCP4.5 and the period of 2016-2075 under RCP8.5 due to reduced precipitation and a warmer climate. In contrast, winter wheat would benefit from increased CO 2 and temperature and was projected to have larger biomass C under both RCP scenarios. Although the climate condition had large differences between RCP4.5 and RCP8.5, the projected SOC had similar trends under two scenarios due to CO 2 fertilizer effect and precipitation fluctuation. These results implied that crop biomass C and SOC accumulation in a warmer environment are strongly related to precipitation, and increase in field water storage should be emphasized in coping with future climate. Copyright © 2016 Elsevier B.V. All rights reserved.

Linking diurnal trends in methylmercury concentration and organic matter photo-reactivity in wetlands of the Yolo Bypass, California

NASA Astrophysics Data System (ADS)

Fleck, J. A.; Downing, B. D.; Saraceno, J.; Gill, G.; Stephenson, M.; Bergamaschi, B. A.

2008-12-01

Aqueous concentrations of methylmercury (MeHg) are known to vary temporally and spatially due to multiple concurrent production and loss mechanisms, and due to variations in the hydrologic connectivity between the methylating substrate (most commonly the benthos) and the overlying water compartments. Diurnal trends in MeHg production, bacterial demethylation, photo-demethylation, diffusion and advection transport processes have been identified and investigated; however, the magnitude and relative importance of each process in mediating overlying water MeHg concentrations, is not well known in natural wetland systems. Temporal variations in aqueous MeHg concentrations may impact the biological accumulation of MeHg into the base of the aquatic food chain, and may challenge regulatory efforts designed to mitigate MeHg exports from point and non-point sources. To identify the possible "hot moments" during the diurnal cycle, surface water MeHg concentrations were monitored in two agricultural wetland settings (wild rice and white rice fields) over a 24- hour period within the Yolo Bypass Wildlife Area, California using a combination of in situ optical sensors and traditional surface-water grab samples. In the wild rice field, MeHg concentrations doubled from 1 ng/L to 2 ng/L over the nighttime hours and returned to 1 ng/L during the daylight hours, whereas the white rice field showed no significant variation in MeHg concentration (0.73 +/- 0.08 ng/L) throughout the diurnal cycle. Similar trends were observed when MeHg data was expressed as a percentage of total Hg, with both wetland habitats exhibiting similar levels (20% MeHg) following the nighttime period and the wild rice field declining to 10% in the early evening. Field parameters measured in situ (including: solar radiation, pH, dissolved oxygen, and temperature) exhibited large diurnal trends in both wetlands, whereas optical proxies for dissolved organic matter (DOM) composition mirrored the fluctuations in MeHg concentration and %MeHg, with a strong diurnal trend in wild rice and no apparent trend in white rice. These results suggest a unique link between DOM photo-reactivity and photo-demethylation in these wetlands that challenges traditional monitoring efforts in terms of defining generalized "hot moments" associated with the diurnal cycling of MeHg in shallow agricultural wetland settings.

Variations in trihalomethane levels in three French water distribution systems and the development of a predictive model.

PubMed

Mouly, Damien; Joulin, Eric; Rosin, Christophe; Beaudeau, Pascal; Zeghnoun, Abdelkrim; Olszewski-Ortar, Agnès; Munoz, Jean François; Welté, Bénédicte; Joyeux, Michel; Seux, René; Montiel, Antoine; Rodriguez, M J

2010-10-01

Epidemiological studies have demonstrated that chlorination by-products in drinking water may cause some types of cancer in humans. However, due to differences in methodology between the various studies, it is not possible to establish a dose-response relationship. This shortcoming is due primarily to uncertainties about how exposure is measured-made difficult by the great number of compounds present-the exposure routes involved and the variation in concentrations in water distribution systems. This is especially true for trihalomethanes for which concentrations can double between the water treatment plant and the consumer tap. The aim of this study is to describe the behaviour of trihalomethanes in three French water distribution systems and develop a mathematical model to predict concentrations in the water distribution system using data collected from treated water at the plant (i.e. the entrance of the distribution system). In 2006 and 2007, samples were taken successively from treated water at the plant and at several points in the water distribution system in three French cities. In addition to the concentrations of the four trihalomethanes (chloroform, dichlorobromomethane, chlorodibromomethane, bromoform), many other parameters involved in their formation that affect their concentration were also measured. The average trihalomethane concentration in the three water distribution systems ranged from 21.6 μg/L to 59.9 μg/L. The increase in trihalomethanes between the treated water at the plant and a given point in the water distribution system varied by a factor of 1.1-5.7 over all of the samples. A log-log linear regression model was constructed to predict THM concentrations in the water distribution system. The five variables used were trihalomethane concentration and free residual chlorine for treated water at the plant, two variables that characterize the reactivity of organic matter (specific UV absorbance (SUVA), an indicator developed for the free chlorine consumption in the treatment plant before distribution δ) and water residence time in the distribution system. French regulations impose a minimum trihalomethane level for drinking water and most tests are performed on treated water at the plant. Applied in this context, the model developed here helps better to understand trihalomethane exposure in the French population, particularly useful for epidemiological studies. Copyright © 2010 Elsevier Ltd. All rights reserved.

Characterization of Electrostatic Potential and Trapped Charge in Semiconductor Nanostructures using Off-Axis Electron Holography

NASA Astrophysics Data System (ADS)

Gan, Zhaofeng

Off-axis electron holography (EH) has been used to characterize electrostatic potential, active dopant concentrations and charge distribution in semiconductor nanostructures, including ZnO nanowires (NWs) and thin films, ZnTe thin films, Si NWs with axial p-n junctions, Si-Ge axial heterojunction NWs, and Ge/Li xGe core/shell NW. The mean inner potential (MIP) and inelastic mean free path (IMFP) of ZnO NWs have been measured to be 15.3V+/-0.2V and 55+/-3nm, respectively, for 200keV electrons. These values were then used to characterize the thickness of a ZnO nano-sheet and gave consistent values. The MIP and IMFP for ZnTe thin films were measured to be 13.7+/-0.6V and 46+/-2nm, respectively, for 200keV electrons. A thin film expected to have a p-n junction was studied, but no signal due to the junction was observed. The importance of dynamical effects was systematically studied using Bloch wave simulations. The built-in potentials in Si NWs across the doped p-n junction and the Schottky junction due to Au catalyst were measured to be 1.0+/-0.3V and 0.5+/-0.3V, respectively. Simulations indicated that the dopant concentrations were ~1019cm-3 for donors and ~1017 cm-3 for acceptors. The effects of positively charged Au catalyst, a possible n+-n --p junction transition region and possible surface charge, were also systematically studied using simulations. Si-Ge heterojunction NWs were studied. Dopant concentrations were extracted by atom probe tomography. The built-in potential offset was measured to be 0.4+/-0.2V, with the Ge side lower. Comparisons with simulations indicated that Ga present in the Si region was only partially activated. In situ EH biasing experiments combined with simulations indicated the B dopant in Ge was mostly activated but not the P dopant in Si. I-V characteristic curves were measured and explained using simulations. The Ge/LixGe core/shell structure was studied during lithiation. The MIP for LixGe decreased with time due to increased Li content. A model was proposed to explain the lower measured Ge potential, and the trapped electron density in Ge core was calculated to be 3x1018 electrons/cm3. The Li amount during lithiation was also calculated using MIP and volume ratio, indicating that it was lower than the fully lithiated phase.

The development of a novel approach for assessment of the first flush in urban stormwater discharges.

PubMed

Bach, P M; McCarthy, D T; Deletic, A

2010-01-01

The management of stormwater pollution has placed particular emphasis on the first flush phenomenon. However, definition and current methods of analyses of the phenomena contain serious limitations, the most important being their inability to capture a possible impact of the event size (total event volume) on the first flush. This paper presents the development of a novel approach in defining and assessing the first flush that should overcome these problems. The phenomenon is present in a catchment if the decrease in pollution concentration with the absolute cumulative volume of runoff from the catchment is statistically significant. Using data from seven diverse catchments around Melbourne, Australia, changes in pollutant concentrations for Total Suspended Solids (TSS) and Total Nitrogen (TN) were calculated over the absolute cumulative runoff and aggregated from a collection of different storm events. Due to the discrete nature of the water quality data, each concentration was calculated as a flow-weighted average at 2 mm runoff volume increments. The aggregated concentrations recorded in each increment (termed as a 'slice' of runoff) were statistically compared to each other across the absolute cumulative runoff volume. A first flush is then defined as the volume at which concentrations reach the 'background concentration' (i.e. the statistically significant minimum). Initial results clearly highlight first flush and background concentrations in all but one catchment supporting the validity of this new approach. Future work will need to address factors, which will help assess the first flush's magnitude and volume. Sensitivity testing and correlation with catchment characteristics should also be undertaken.

The urban environmental gradient: Anthropogenic influences on the spatial and temporal distributions of lead and zinc in sediments

USGS Publications Warehouse

Callender, Edward; Rice, Karen C.

2000-01-01

Urban settings are a focal point for environmental contamination due to emissions from industrial and municipal activities and the widespread use of motor vehicles. As part of the National Water-Quality Assessment Program of the U.S. Geological Survey, streambed-sediment and dated reservoir-sediment samples were collected from the Chattahoochee River Basin and analyzed for total lead (Pb) and zinc (Zn) concentrations. The sampling transect extends from northern Georgia, through Atlanta, to the Gulf of Mexico and reflects a steep gradient in population density from nearly 1000 people/km2 in the Atlanta Metropolitan Area to fewer than 50 people/km2 in rural areas of southern Georgia and northern Florida. Correlations among population density, traffic density, and total and anthropogenic Pb and Zn concentrations indicate that population density is strongly related to traffic density and is a predictor of Pb and Zn concentrations in the environment derived from anthropogenic activities. Differences in the distributions of total Pb and Zn concentrations along the urban−suburban−rural gradient from Atlanta to the Florida Panhandle are related to temporal and spatial processes. That is, with the removal of leaded gasoline starting in the late 1970s, peak Pb concentrations have decreased to the present. Conversely, increased vehicular usage has kept Zn concentrations elevated in runoff from population centers, which is reflected in the continued enrichment of Zn in aquatic sediments. Sediments from rural areas also contain elevated concentrations of Zn, possibly in response to substantial power plant emissions for the region, as well as vehicular traffic.

Effects of PEG-induced osmotic stress on growth and dhurrin levels of forage sorghum.

PubMed

O'Donnell, Natalie H; Møller, Birger Lindberg; Neale, Alan D; Hamill, John D; Blomstedt, Cecilia K; Gleadow, Roslyn M

2013-12-01

Sorghum (Sorghum bicolor L. Moench) is a valuable forage crop in regions with low soil moisture. Sorghum may accumulate high concentrations of the cyanogenic glucoside dhurrin when drought stressed resulting in possible cyanide (HCN) intoxication of grazing animals. In addition, high concentrations of nitrate, also potentially toxic to ruminants, may accumulate during or shortly after periods of drought. Little is known about the degree and duration of drought-stress required to induce dhurrin accumulation, or how changes in dhurrin concentration are influenced by plant size or nitrate metabolism. Given that finely regulating soil moisture under controlled conditions is notoriously difficult, we exposed sorghum plants to varying degrees of osmotic stress by growing them for different lengths of time in hydroponic solutions containing polyethylene glycol (PEG). Plants grown in medium containing 20% PEG (-0.5 MPa) for an extended period had significantly higher concentrations of dhurrin in their shoots but lower dhurrin concentrations in their roots. The total amount of dhurrin in the shoots of plants from the various treatments was not significantly different on a per mass basis, although a greater proportion of shoot N was allocated to dhurrin. Following transfer from medium containing 20% PEG to medium lacking PEG, shoot dhurrin concentrations decreased but nitrate concentrations increased to levels potentially toxic to grazing ruminants. This response is likely due to the resumption of plant growth and root activity, increasing the rate of nitrate uptake. Data presented in this article support a role for cyanogenic glucosides in mitigating oxidative stress. Copyright © 2013 Elsevier Masson SAS. All rights reserved.