Stable isotope tracer dilution for quantifying very low-density lipoprotein-triacylglycerol kinetics in man.

PubMed

Sidossis, Labros S; Magkos, Faidon; Mittendorfer, Bettina; Wolfe, Robert R

2004-08-01

A number of approaches have been employed in the past to measure very low-density lipoprotein (VLDL) triacylglycerol (TG) kinetics in humans in vivo, varying in the selection of tracer and mode of administration. All, however, make use of labeled TG precursors and more or less complicated mathematical models to derive the kinetic parameters of interest. The aim of the present study was to develop a conceptually straightforward method, based on the traditional tracer infusion technique, for quantifying VLDL-TG production rates in man using stable isotopes. Our approach involves ingestion of [U-13C3]glycerol to endogenously label the glycerol in VLDL-TG, plasmapheresis, isolation of the newly 13C-labeled VLDL from plasma, and administration within the next 2-3 days via a primed constant autologous reinfusion. This procedure produces enough tracer for a priming dose plus 2-3 h of infusion. In the physiological conditions examined (basal and hyperglycemic states, fat- and carbohydrate-rich diets), with almost 3-fold ranging VLDL-TG pool sizes, a steady state in plasma VLDL-TG glycerol tracer-to-tracee ratio was readily achieved within 2 h. Consequently, calculations are made according to the isotope dilution principle, thus avoiding assumptions implicit in more complicated models. The stable isotope VLDL-TG tracer dilution method offers an alternative and reliable tool for the determination of endogenous VLDL-TG kinetics in man under a variety of metabolic states. Copyright 2003 Elsevier Ltd.

EMJH medium with 5-fluorouracil and nalidixic acid associated with serial dilution technique used to recover Leptospira spp from experimentally contaminated bovine semen

PubMed Central

Miraglia, Fabiana; de Moraes, Zenaide Maria; Melville, Priscilla Anne; Dias, Ricardo Augusto; Vasconcellos, Silvio Arruda

2009-01-01

Bovine semen experimentally contaminated with Leptospira santarosai serovar Guaricura was submitted to the modified EMJH medium with 5-fluorouracil (300mg/L) and nalidixic acid (20mg/L), named as “selective medium” and using the serial dilution technique, in order to evaluate the percentage of recovery of the added microorganism. The selective EMJH medium was found with higher percentage of recovery of leptospiras and minor losses of samples due to contamination with opportunistic microorganisms than the non-selective EMJH medium: 151/376 (40.0%) of positive growth; and 38/376 (10.0%) contamination and 58/376 (15%) and 129/376 (34.0%), respectively. These results were statistically significant (p<0. 0001; Fisher). Differences were found when the frequencies of positive leptospires recovery have been compared in the serial dilution technique (10-1 to 10-4) between the selective and non-selective media at different dilution factors. At 1/10th dilution the percentages found were (0%, 0/80) and (38%, 30/80), at 1/100th dilution, (3%, 2/80) and (49%, 39/ 80) and at 1/1,000th dilution, (25%, 20/80) and (50%, 40/80), respectively. The percentage of recovery of leptospires was found to be directly proportional to the dilution used. The methodology of the serial dilution technique (setting at least three dilutions) and the use of selective EMJH medium have been found to be efficient for the isolation of leptospires from the bovine semen samples. PMID:24031342

Screening fungicides for use in fish culture: Evaluation of the agar plug transfer, cellophane transfer, and agar dilution methods

USGS Publications Warehouse

Bailey, Tom A.

1983-01-01

The reliability, reproducibility, and usefulness of three screening methods -- the cellophane transfer, the agar plug transfer, and the agar dilution -- to screen aquatic fungicides were evaluated. Achlya flagellata and Saprolegnia hypogyna were exposed to 1, 10, and 100 mg/L of malachite green to test each method. The cellophane transfer and agar plug transfer techniques had similar reliability and reproducibility in rating fungicidal activity, and were both superior to the agar dilution technique. The agar plug transfer and agar dilution techniques adequately projected in vivo activity of malachite green, but the cellophane transfer technique overestimated its activity. Overall, the agar plug transfer technique most accurately rated the activity of malachite green and was the easiest test to perform. It therefore appears to be the method of choice for testing aquatic fungicides.

Metabolic modeling of dynamic 13C NMR isotopomer data in the brain in vivo: Fast screening of metabolic models using automated generation of differential equations

PubMed Central

Tiret, Brice; Shestov, Alexander A.; Valette, Julien; Henry, Pierre-Gilles

2017-01-01

Most current brain metabolic models are not capable of taking into account the dynamic isotopomer information available from fine structure multiplets in 13C spectra, due to the difficulty of implementing such models. Here we present a new approach that allows automatic implementation of multi-compartment metabolic models capable of fitting any number of 13C isotopomer curves in the brain. The new automated approach also makes it possible to quickly modify and test new models to best describe the experimental data. We demonstrate the power of the new approach by testing the effect of adding separate pyruvate pools in astrocytes and neurons, and adding a vesicular neuronal glutamate pool. Including both changes reduced the global fit residual by half and pointed to dilution of label prior to entry into the astrocytic TCA cycle as the main source of glutamine dilution. The glutamate-glutamine cycle rate was particularly sensitive to changes in the model. PMID:26553273

Measurements of left-to-right intracardiac shunting in adults: oximetric versus indicator dilution techniques.

PubMed

Hillis, L D; Winniford, M D; Jackson, J A; Firth, B G

1985-01-01

Of the various techniques that are available to assess the presence and magnitude of intracardiac shunting, oximetry and indicator dilution are used most frequently. This study was performed to compare these methods in adult patients with pure left-to-right intracardiac shunting. In 27 patients [12 men, 15 women, aged 32 +/- 12 (mean +/- SD) years], shunt magnitude was assessed in close temporal proximity by both techniques. The oximetric percentage left-to-right shunt averaged 55 +/- 16%, whereas the indocyanine green dye percentage shunt was significantly less (36 +/- 14%, p less than 0.001). The oximetric percentage shunt exceeded the indocyanine green dye percentage shunt in 26 and did so by greater than 20% in 23 patients. Thus, there is a substantial difference in shunt magnitude between the oximetric and the indicator dilution techniques. In infants, indicator dilution yields results that are larger than those obtained with the oximetric method. Conversely, in adults, the indicator dilution technique gives results that are consistently smaller than those obtained with oximetry. As a result, the decision regarding therapy of an intracardiac shunt should be made with this in mind.

Deuterium dilution technique for body composition assessment: resolving methodological issues in children with moderate acute malnutrition.

PubMed

Fabiansen, Christian; Yaméogo, Charles W; Devi, Sarita; Friis, Henrik; Kurpad, Anura; Wells, Jonathan C

2017-08-01

Childhood malnutrition is highly prevalent and associated with high mortality risk. In observational and interventional studies among malnourished children, body composition is increasingly recognised as a key outcome. The deuterium dilution technique has generated high-quality data on body composition in studies of infants and young children in several settings, but its feasibility and accuracy in children suffering from moderate acute malnutrition requires further study. Prior to a large nutritional intervention trial among children with moderate acute malnutrition, we conducted pilot work to develop and adapt the deuterium dilution technique. We refined procedures for administration of isotope doses and collection of saliva. Furthermore, we established that equilibration time in local context is 3 h. These findings and the resulting standard operating procedures are important to improve data quality when using the deuterium dilution technique in malnutrition studies in field conditions, and may encourage a wider use of isotope techniques.

Microbioassay of Antimicrobial Agents

PubMed Central

Simon, Harold J.; Yin, E. Jong

1970-01-01

A previously described agar-diffusion technique for microbioassay of antimicrobial agents has been modified to increase sensitivity of the technique and to extend the range of antimicrobial agents to which it is applicable. This microtechnique requires only 0.02 ml of an unknown test sample for assay, and is capable of measuring minute concentrations of antibiotics in buffer, serum, and urine. In some cases, up to a 20-fold increase in sensitivity is gained relative to other published standardized methods and the error of this method is less than ±5%. Buffer standard curves have been established for this technique, concurrently with serum standard curves, yielding information on antimicrobial serum-binding and demonstrating linearity of the data points compared to the estimated regression line for the microconcentration ranges covered by this technique. This microassay technique is particularly well suited for pediatric research and for other investigations where sample volumes are small and quantitative accuracy is desired. Dilution of clinical samples to attain concentrations falling with the range of this assay makes the technique readily adaptable and suitable for general clinical pharmacological studies. The microassay technique has been standardized in buffer solutions and in normal human serum pools for the following antimicrobials: ampicillin, methicillin, penicillin G, oxacillin, cloxacillin, dicloxacillin, cephaloglycin, cephalexin, cephaloridine, cephalothin, erythromycin, rifamycin amino methyl piperazine, kanamycin, neomycin, streptomycin, colistin, polymyxin B, doxycycline, minocycline, oxytetracycline, tetracycline, and chloramphenicol. PMID:4986725

Mobil-Badger technologies for benzene reduction in gasoline

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

Goelzer, A.R.; Ram, S.; Hernandez, A.

1993-01-01

Many refiners will need to reduce the barrels per day of benzene entering the motor gasoline pool. Mobil and Badger have developed and now jointly license three potential refinery alternatives to conventional benzene hydrosaturation to achieve this: Mobil Benzene Reduction, Ethylbenzene and Cumene. The Mobil Benzene Reduction Process (MBR) uses dilute olefins in FCC offgas to extensively alkylate dilute benzene as found in light reformate, light FCC gasoline, or cyclic C[sub 6] naphtha. MBR raises octanes and lowers C[sub 5]+ olefins. MBR does not involve costly hydrogen addition. The refinery-based Mobil/Badger Ethylbenzene Process reacts chemical-grade benzene extracted from light reformatemore » with dilute ethylene found in treated FCC offgas to make high-purity ethylbenzene. EB is the principal feedstock for the production of styrene. The Mobil/Badger Cumene Process alkylates FCC-derived dilute propylene and extracted benzene to selectively yield isopropyl benzene (cumene). Cumene is the principal feedstock for the production of phenol. All three processes use Mobil developed catalysts.« less

Reduction of hexavalent chromium by fasted and fed human gastric fluid. II. Ex vivo gastric reduction modeling

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

Kirman, Christopher R., E-mail: ckirman@summittoxi

To extend previous models of hexavalent chromium [Cr(VI)] reduction by gastric fluid (GF), ex vivo experiments were conducted to address data gaps and limitations identified with respect to (1) GF dilution in the model; (2) reduction of Cr(VI) in fed human GF samples; (3) the number of Cr(VI) reduction pools present in human GF under fed, fasted, and proton pump inhibitor (PPI)-use conditions; and (4) an appropriate form for the pH-dependence of Cr(VI) reduction rate constants. Rates and capacities of Cr(VI) reduction were characterized in gastric contents from fed and fasted volunteers, and from fasted pre-operative patients treated with PPIs.more » Reduction capacities were first estimated over a 4-h reduction period. Once reduction capacity was established, a dual-spike approach was used in speciated isotope dilution mass spectrometry analyses to characterize the concentration-dependence of the 2nd order reduction rate constants. These data, when combined with previously collected data, were well described by a three-pool model (pool 1 = fast reaction with low capacity; pool 2 = slow reaction with higher capacity; pool 3 = very slow reaction with higher capacity) using pH-dependent rate constants characterized by a piecewise, log-linear relationship. These data indicate that human gastric samples, like those collected from rats and mice, contain multiple pools of reducing agents, and low concentrations of Cr(VI) (< 0.7 mg/L) are reduced more rapidly than high concentrations. The data and revised modeling results herein provide improved characterization of Cr(VI) gastric reduction kinetics, critical for Cr(VI) pharmacokinetic modeling and human health risk assessment. - Highlights: • SIDMS allows for measurement of Cr(VI) reduction rate in gastric fluid ex vivo • Human gastric fluid has three reducing pools • Cr(VI) in drinking water at < 0.7 mg/L is rapidly reduced in human gastric fluid • Reduction rate is concentration- and pH-dependent • A refined PK model is used to characterize inter-individual variability in Cr(VI) gastric reduction capacity.« less

Cardiac output monitoring using indicator-dilution techniques: basics, limits, and perspectives.

PubMed

Reuter, Daniel A; Huang, Cecil; Edrich, Thomas; Shernan, Stanton K; Eltzschig, Holger K

2010-03-01

The ability to monitor cardiac output is one of the important cornerstones of hemodynamic assessment for managing critically ill patients at increased risk for developing cardiac complications, and in particular in patients with preexisting cardiovascular comorbidities. For >30 years, single-bolus thermodilution measurement through a pulmonary artery catheter for assessment of cardiac output has been widely accepted as the "clinical standard" for advanced hemodynamic monitoring. In this article, we review this clinical standard, along with current alternatives also based on the indicator-dilution technique, such as the transcardiopulmonary thermodilution and lithium dilution techniques. In this review, not only the underlying technical principles and the unique features but also the limitations of each application of indicator dilution are outlined.

Quantification of transformation rates of soil amino sugars and amino acids by a novel isotope pool dilution approach via liquid chromatography/high resolution mass spectrometry (LC/HRMS)

NASA Astrophysics Data System (ADS)

Hu, Yuntao; Zheng, Qing; Noll, Lisa; Zhang, Shasha; Wanek, Wolfgang

2017-04-01

Organic nitrogen transformation processes are the key driver of soil nitrogen availability, strongly affecting the nitrogen turnover and carbon cycling of terrestrial ecosystems. Low molecular weight organic nitrogen compounds (e.g. amino acids and amino sugars) that can be directly utilized by plants or microorganisms are released by the extracellular cleavage of high molecular weight organic nitrogen compounds (e.g. proteins, peptidoglycan, and chitin) by hydrolytic enzymes. This decomposition process is believed to be the rate-limiting step in the soil N cycle. Direct measurements of the in situ transformation rates of these small N compounds is highly challenging but can be realized by applying the isotope pool dilution (IPD) technique, in which the target compound pool is labeled with isotopic tracers and subsequently the dilution of the tracers is measured. We have recently pioneered the development of IPD assays to investigate the in situ flux of proteinaceous amino acids and glucose due to decomposition of organic matter and microbial utilization, but the roles of fluxes of amino sugars and amino acid enantiomers in soil nitrogen transformation processes are still unknown due to the lack of feasible extraction, purification, separation and detection methods. Here we developed a 15N IPD assay by utilizing a novel LC/HRMS (Orbitrap) platform, with the aim to measure transformation rates of amino sugars and amino acid enantiomers. After the tracer experiments soil extracts were purified by solid phase extraction prior to the analysis by MS. The utilization of Orbitrap-HRMS allowed us to resolve the mass signals of unlabeled analytes, and their 15N labeled (tracers) and 13C labeled (internal standards) analogues. The commercially unavailable 15N and 13C labeled amino sugars and amino acid enantiomers were produced from bacterial cell walls after batch culture in labeled growth media. This workflow was validated with soils from two sampling sites, allowing us to successfully investigate the production and consumption of 2 amino sugars, 18 amino acids, and 4 amino acid enantiomers in soils. We further applied this method to soils from 6 sampling sites differing in geology and land management, after short-term (1-day) temperature (5˚ C, 15˚ C, 25˚ C) pre-incubations. We found that the release of amino sugars (free glucosamine) during the decomposition of peptidoglycan and chitin accounted for approximately 5% to 15% of the total influx into the dissolved organic nitrogen pool (amino acids plus amino sugars). Muramic acid exhibited significantly longer residence times in soils, indicating that free muramic acid was not an important decomposition product of peptidoglycan in soil. We will present further results on potential controls of soil amino sugar fluxes, such as soil temperature, geology and land management, as well as soil peptidoglycan and chitin content, hydrolytic enzyme activity, and microbial community structure. These findings and further ongoing work will greatly advance our knowledge of the transformation processes of soil organic nitrogen and its major controls.

Application of isotope dilution technique in vitamin A nutrition.

PubMed

Wasantwisut, Emorn

2002-09-01

The isotope dilution technique involving deuterated retinol has been developed to quantitatively estimate total body reserves of vitamin A in humans. The technique provided good estimates in comparison to hepatic vitamin A concentrations in Bangladeshi surgical patients. Kinetic studies in the United States, Bangladesh, and Guatemala indicated the mean equilibration time of 17 to 20 days irrespective of the size of hepatic reserves. Due to the controversy surrounding the efficacy of a carotene-rich diet on improvement of vitamin A status, the isotope dilution technique was proposed to pursue this research question further (IAEA's coordinated research program). In the Philippines, schoolchildren with low serum retinol concentrations showed significant improvement in total body vitamin A stores following intake of carotene-rich foods (orange fruits and vegetables), using a three-day deuterated-retinol-dilution procedure. When Chinese kindergarten children were fed green and yellow vegetables during the winter, their total body vitamin A stores were sustained as compared to a steady decline of vitamin A stores in the control children. Likewise, daily consumption of purified beta-carotene or diet rich in provitamin A carotenoids were shown to prevent a loss in total body vitamin A stores among Thai lactating women during the rice-planting season. These studies demonstrate potentials of the isotope dilution technique to evaluate the impact of provitamin A carotenoid intervention programs.

[Effect of prescribed burning on grassland nitrogen gross mineralization and nitrification].

PubMed

Li, Yuzhong; Zhu, Tingcheng; Li, Jiandong; Zhou, Daowei

2003-02-01

The seasonal dynamics of nitrogen gross mineralization, nitrification, and mineral nitrogen consumption rates in burned and unburned Leymus chinensis grasslands were studied with 15N pool dilution technique. The results indicated that the gross mineralization and nitrification rates in burned area were higher than those in unburned area in April and May, and lower than those in unburned area in September. NH4(+)-N consumption rates were higher than unburned area in April and May, and lower in September. NO3(-)-N consumption rates were higher than control in April and May, and lower than control in July and September. The NH4(+)-N concentrations were higher in burned area in April, May and July, and no difference in September. NO3(-)-N concentrations were no difference between burned and unburned areas in April and May, and higher in burned areas in July and September.

Short communication: milk output in llamas (Lama glama) in relation to energy intake and water turnover measured by an isotope dilution technique.

PubMed

Riek, A; Klinkert, A; Gerken, M; Hummel, J; Moors, E; Südekum, K-H

2013-03-01

Despite the fact that llamas have become increasingly popular as companion and farm animals in both Europe and North America, scientific knowledge on their nutrient requirements is scarce. Compared with other livestock species, relatively little is known especially about the nutrient and energy requirements for lactating llamas. Therefore, we aimed to measure milk output in llama dams using an isotope dilution technique and relate it to energy intakes at different stages of lactation. We also validated the dilution technique by measuring total water turnover (TWT) directly and comparing it with values estimated by the isotope dilution technique. Our study involved 5 lactating llama dams and their suckling young. Milk output and TWT were measured at 4 stages of lactation (wk 3, 10, 18, and 26 postpartum). The method involved the application of the stable hydrogen isotope deuterium ((2)H) to the lactating dam. Drinking water intake and TWT decreased significantly with lactation stage, whether estimated by the isotope dilution technique or calculated from drinking water and water ingested from feeds. In contrast, lactation stage had no effect on dry matter intake, metabolizable energy (ME) intake, or the milk water fraction (i.e., the ratio between milk water excreted and TWT). The ratios between TWT measured and TWT estimated (by isotope dilution) did not differ with lactation stage and were close to 100% in all measurement weeks, indicating that the D(2)O dilution technique estimated TWT with high accuracy and only small variations. Calculating the required ME intakes for lactation from milk output data and gross energy content of milk revealed that, with increasing lactation stage, ME requirements per day for lactation decreased but remained constant per kilogram of milk output. Total measured ME intakes at different stages of lactation were similar to calculated ME intakes from published recommendation models for llamas. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Lipid and Creatinine Adjustment to Evaluate Health Effects of Environmental Exposures.

PubMed

O'Brien, Katie M; Upson, Kristen; Buckley, Jessie P

2017-03-01

Urine- and serum-based biomarkers are useful for assessing individuals' exposure to environmental factors. However, variations in urinary creatinine (a measure of dilution) or serum lipid levels, if not adequately corrected for, can directly impact biomarker concentrations and bias exposure-disease association measures. Recent methodological literature has considered the complex relationships between creatinine or serum lipid levels, exposure biomarkers, outcomes, and other potentially relevant factors using directed acyclic graphs and simulation studies. The optimal measures of urinary dilution and serum lipids have also been investigated. Existing evidence supports the use of covariate-adjusted standardization plus creatinine adjustment for urinary biomarkers and standardization plus serum lipid adjustment for lipophilic, serum-based biomarkers. It is unclear which urinary dilution measure is best, but all serum lipid measures performed similarly. Future research should assess methods for pooled biomarkers and for studying diseases and exposures that affect creatinine or serum lipids directly.

Lipid and Creatinine Adjustment to Evaluate Health Effects of Environmental Exposures

PubMed Central

O’Brien, Katie M.; Upson, Kristen; Buckley, Jessie P.

2017-01-01

Purpose of review Urine- and serum-based biomarkers are useful for assessing individuals’ exposure to environmental factors. However, variations in urinary creatinine (a measure of dilution) or serum lipid levels, if not adequately corrected for, can directly impact biomarker concentrations and bias exposure-disease association measures. Recent findings Recent methodological literature has considered the complex relationships between creatinine or serum lipid levels, exposure biomarkers, outcomes, and other potentially relevant factors using directed acyclic graphs and simulation studies. The optimal measures of urinary dilution and serum lipids have also been investigated. Summary Existing evidence supports the use of covariate-adjusted standardization plus creatinine adjustment for urinary biomarkers and standardization plus serum lipid adjustment for lipophilic, serum-based biomarkers. It is unclear which urinary dilution measure is best, but all serum lipid measures performed similarly. Future research should assess methods for pooled biomarkers and for studying diseases and exposures that affect creatinine or serum lipids directly. PMID:28097619

Clinical performance evaluation of total protein measurement by digital refractometry and characterization of non-protein solute interferences.

PubMed

Hunsaker, Joshua J H; Wyness, Sara P; Snow, Taylor M; Genzen, Jonathan R

2016-12-01

Refractometric methods to measure total protein (TP) in serum and plasma specimens have been replaced by automated biuret methods in virtually all routine clinical testing. A subset of laboratories, however, still report using refractometry to measure TP in conjunction with serum protein electrophoresis. The objective of this study was therefore to conduct a modern performance evaluation of a digital refractometer for TP measurement. Performance evaluation of a MISCO Palm Abbe™ digital refractometer was conducted through device familiarization, carryover, precision, accuracy, linearity, analytical sensitivity, analytical specificity, and reference interval verification. Comparison assays included a manual refractometer and an automated biuret assay. Carryover risk was eliminated using a demineralized distilled water (ddH 2 O) wash step. Precision studies demonstrated overall imprecision of 2.2% CV (low TP pool) and 0.5% CV (high TP pool). Accuracy studies demonstrated correlation to both manual refractometry and the biuret method. An overall positive bias (+5.0%) was observed versus the biuret method. On average, outlier specimens had an increased triglyceride concentration. Linearity was verified using mixed dilutions of: a) low and high concentration patient pools, or b) albumin-spiked ddH 2 O and high concentration patient pool. Decreased recovery was observed using ddH 2 O dilutions at low TP concentrations. Significant interference was detected at high concentrations of glucose (>267 mg/dL) and triglycerides (>580 mg/dL). Current laboratory reference intervals for TP were verified. Performance characteristics of this digital refractometer were validated in a clinical laboratory setting. Biuret method remains the preferred assay for TP measurement in routine clinical analyses.

Laboratory evaluation of sample collection methods (organs vs swabs) for Tasmanian salmon reovirus detection in farmed Atlantic salmon, Salmo salar L.

PubMed

Zainathan, S C; Carson, J; Crane, M St J; Nowak, B F

2013-04-01

The use of swabs relative to organs as a sample collection method for the detection of Tasmanian salmon reovirus (TSRV) in farmed Tasmanian Atlantic salmon, Salmo salar L., was evaluated by RT-qPCR. Evaluation of individual and pooled sample collection (organs vs swabs) was carried out to determine the sensitivity of the collection methods and the effect of pooling of samples for the detection of TSRV. Detection of TSRV in individual samples was as sensitive when organs were sampled compared to swabs, and in pooled samples, organs demonstrated a sensitivity of one 10-fold dilution higher than sampling of pooled swabs. Storage of swabs at 4 °C for t = 24 h demonstrated results similar to those at t = 0. Advantages of using swabs as a preferred sample collection method for the detection of TSRV compared to organ samples are evident from these experimental trials. © 2012 Blackwell Publishing Ltd.

Changes of jugular venous blood temperature associated with measurements of cerebral blood flow using the transcerebral double-indicator dilution technique.

PubMed

Mielck, F; Bräuer, A; Radke, O; Hanekop, G; Loesch, S; Friedrich, M; Hilgers, R; Sonntag, H

2004-04-01

The transcerebral double-indicator dilution technique is a recently developed method to measure global cerebral blood flow at bedside. It is based on bolus injection of ice-cold indocyanine green dye and simultaneous recording of resulting thermo- and dye-dilution curves in the aorta and the jugular bulb. However, with this method 40 mL of ice-cold solution is administered as a bolus. Therefore, this prospective clinical study was performed to elucidate the effects of repeated administration of indicator on absolute blood temperature and on cerebral blood flow and metabolism. The investigation was performed in nine male patients scheduled for elective coronary artery bypass grafting. Absolute blood temperature was measured in the jugular bulb and in the aorta before and after repeated measurements using the transcerebral double-indicator dilution technique. During the investigated time course, the blood temperature in the jugular bulb, compared to the aorta, was significantly higher with a mean difference of 0.21 degrees C. The administration of an ice-cold bolus reduced the mean blood temperature by 0.06 degrees C in the jugular bulb as well as in the aorta. After the transcerebral double-indicator dilution measurements a temperature recovery to baseline conditions was not observed during the investigated time period. Cerebral blood flow and cerebral metabolism did not change during the investigated time period. Repeated measurements with the transcerebral double-indicator dilution technique do not affect absolute jugular bulb blood temperatures negatively. Global cerebral blood flow and metabolism measurements remain unaltered. However, accuracy and resolution of this technique is not high enough to detect the effect of minor changes of physiological variables.

Thromboresistant surface coatings for the measurement of cardiac output through continuous low flow peripheral A-V shunts.

PubMed Central

Deeb, G M; Borovetz, H S; Griffith, B P; Hardesty, R L

1980-01-01

The dilution technique for determining cardiac output using indocyanine green dye is limited in patients weighing less than 20 kg because of the obligatory volume loss. Reproducible achieved using the green dye dilution method by the establishment of a low flow peripheral arteriovenous shunt. The shunt materials were treated with thromboresistant agents--TDMAC (7%) and albumin (1 g/dl)--to facilitate the use of this technique without heparin. For A-V shunt flow rates of 8-30 cc/min reproducible values of cardiac output were obtained for up to 38 hours which were in good agreement with determinations made using the conventional technique of dye dilution. PMID:6986120

Comparison of individual and pooled stool samples for the assessment of intensity of Schistosoma mansoni and soil-transmitted helminth infections using the Kato-Katz technique.

PubMed

Kure, Ashenafi; Mekonnen, Zeleke; Dana, Daniel; Bajiro, Mitiku; Ayana, Mio; Vercruysse, Jozef; Levecke, Bruno

2015-09-24

Our group has recently provided a proof-of-principle for the examination of pooled stool samples using McMaster technique as a strategy for the rapid assessment of intensity of soil-transmitted helminth infections (STH, Ascaris lumbricoides, Trichuris trichiura and hookworm). In the present study we evaluated this pooling strategy for the assessment of intensity of both STH and Schistosoma mansoni infections using the Kato-Katz technique. A cross-sectional survey was conducted in 360 children aged 5-18 years from six schools in Jimma Zone (southwest Ethiopia). We performed faecal egg counts (FECs) in both individual and pooled samples (pools sizes of 5, 10 and 20) to estimate the number of eggs per gram of stool (EPG) using the Kato-Katz technique. We also assessed the time to screen both individual and pooled samples. Except for hookworms, there was a significant correlation (correlation coefficient = 0.53-0.95) between the mean of individual FECs and the FECs of pooled samples for A. lumbricoides, T. trichiura and S. mansoni, regardless of the pool size. Mean FEC were 2,596 EPG, 125 EPG, 47 EPG, and 41 EPG for A. lumbricoides, T. trichiura, S. mansoni and hookworm, respectively. There was no significant difference in FECs between the examination of individual and pooled stool samples, except for hookworms. For this STH, pools of 10 resulted in a significant underestimation of infection intensity. The total time to obtain individual FECs was 65 h 5 min. For pooled FECs, this was 19 h 12 min for pools of 5, 14 h 39 min for pools of 10 and 12 h 42 min for pools of 20. The results indicate that pooling of stool sample holds also promise as a rapid assessment of infections intensity for STH and S. mansoni using the Kato-Katz technique. In this setting, the time in the laboratory was reduced by 70 % when pools of 5 instead of individual stool samples were screened.

An Investigation Into the Effects of In Vitro Dilution With Different Colloid Resuscitation Fluids on Clot Microstructure Formation.

PubMed

Lawrence, Matthew James; Marsden, Nick; Kaczynski, Jakub; Davies, Gareth; Davies, Nia; Hawkins, Karl; Perumal, Sounder; Brown, Martin Rowan; Morris, Keith; Davidson, Simon J; Williams, Phylip Rhodri; Evans, Phillip Adrian

2016-11-01

Balancing the beneficial effects of resuscitation fluids against their detrimental effect on hemostasis is an important clinical issue. We aim to compare the in vitro effects of 3 different colloid resuscitation fluids (4.5% albumin, hydroxyethyl starch [Voluven 6%], and gelatin [Geloplasma]) on clot microstructure formation using a novel viscoelastic technique, the gel point. This novel hemorheologic technique measures the biophysical properties of the clot and provides an assessment of clot microstructure from its viscoelastic properties. Importantly, in contrast to many assays in routine clinical use, the measurement is performed using unadulterated whole blood in a near-patient setting and provides rapid assessment of coagulation. We hypothesized that different colloids will have a lesser or greater detrimental effect on clot microstructure formation when compared against each other. Healthy volunteers were recruited into the study (n = 104), and a 20-mL sample of whole blood was obtained. Each volunteer was assigned to 1 of the 3 fluids, and the sample was diluted to 1 of 5 different dilutions (baseline, 10%, 20%, 40%, and 60%). The blood was tested using the gel point technique, which measures clot mechanical strength and quantifies clot microstructure (df) at the incipient stages of fibrin formation. df and clot mechanical strength decrease with progressive dilution for all 3 fluids. A significant reduction in df from baseline was recorded at dilutions of 20% for albumin (P < .0001), 40% for starch (P < .0001), and 60% for gelatin (P < .0001). We also observed significant differences, in terms of df, when comparing the different types of colloid (P < .0001). We found that albumin dilution produced the largest changes in clot microstructure, providing the lowest values of df (= 1.41 ± 0.061 at 60% dilution) compared with starch (1.52 ± 0.081) and gelatin (1.58 ± 0.063). We show that dilution with all 3 fluids has a significant effect on coagulation at even relatively low dilution volumes (20% and 40%). Furthermore, we quantify, using a novel viscoelastic technique, how the physiochemical properties of the 3 colloids exert individual changes on clot microstructure.

Alcoholism Detection by Data Augmentation and Convolutional Neural Network with Stochastic Pooling.

PubMed

Wang, Shui-Hua; Lv, Yi-Ding; Sui, Yuxiu; Liu, Shuai; Wang, Su-Jing; Zhang, Yu-Dong

2017-11-17

Alcohol use disorder (AUD) is an important brain disease. It alters the brain structure. Recently, scholars tend to use computer vision based techniques to detect AUD. We collected 235 subjects, 114 alcoholic and 121 non-alcoholic. Among the 235 image, 100 images were used as training set, and data augmentation method was used. The rest 135 images were used as test set. Further, we chose the latest powerful technique-convolutional neural network (CNN) based on convolutional layer, rectified linear unit layer, pooling layer, fully connected layer, and softmax layer. We also compared three different pooling techniques: max pooling, average pooling, and stochastic pooling. The results showed that our method achieved a sensitivity of 96.88%, a specificity of 97.18%, and an accuracy of 97.04%. Our method was better than three state-of-the-art approaches. Besides, stochastic pooling performed better than other max pooling and average pooling. We validated CNN with five convolution layers and two fully connected layers performed the best. The GPU yielded a 149× acceleration in training and a 166× acceleration in test, compared to CPU.

Soil nitrogen dynamics within profiles of a managed moist temperate forest chronosequence consistent with long-term harvesting-induced losses

NASA Astrophysics Data System (ADS)

Kellman, Lisa; Kumar, Sanjeev; Diochon, Amanda

2014-07-01

This study investigates whether clear-cut forest harvesting leads to alterations in the decadal-scale biogeochemical nitrogen (N) cycles of moist temperate forest ecosystems. Using a harvested temperate red spruce (Picea rubens Sarg.) forest chronosequence in Nova Scotia, Canada, representing <1 to >80 year old postharvest conditions, alongside a reference old-growth (125+ year old) site with no documented history of disturbance, we examine harvesting-related changes in soil N pools and fluxes. Specifically, we quantify soil N storage with depth and age across the forest chronosequence, examine changes in physical fractions and δ15N of soil N through depth and time, and quantify gross soil N transformation rates through depth and time using a 15N isotope dilution technique. Our findings point to a large loss of total N in the soil pool, particularly within the deep soil (>20 cm) and organomineral fractions. A pulse of available mineralized N (as ammonium) was observed following harvesting (mean residence time (MRT) > 6 days), but its MRT dropped to <1 day 80 years following harvesting, in contrast to the MRT of 2-3 days observed in the reference old-growth forest site. These mineralization patterns coupled with inferred leaching losses to groundwater are consistent with storage estimates that suggest soil N may not reaccrue for almost a century following this disturbance.

Bile salt kinetics in cystic fibrosis: influence of pancreatic enzyme replacement

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

Watkins, J.B.; Tercyak, A.M.; Szczepanik, P.

1977-01-01

Bile acid kinetics was investigated by stable isotope dilution technique in 6 children (ages 3/sup 1///sub 2/ months to 4/sup 1///sub 2/ years) with previously untreated cystic fibrosis. All of the patients had clinical and laboratory evidence of malabsorption, normal intestinal mucosal function, as judged by glucose absorption, intestinal histology, disaccharidase levels, and normally functioning gallbladders. The children were maintained on a constant diet throughout the study period; fat intake averaged 4.2 g per kg per day. Before administration of pancreatic enzyme replacement, fat excretion equalled 50 +- 4% (mean +- SE) of intake and was reduced to 20 +-more » 1.0% of intake after therapy. Total bile acid pool size nearly doubled during enzyme replacement from 379 +- 32 ..mu..moles per kg to 620 +- 36 ..mu..moles per kg with secondary bile acids comprising 57% of the total pool before therapy and 40% after therapy. The data indicate that both primary and secondary bile acids are conserved within the enterohepatic circulation during enzyme therapy, and that the mechanism for the regulation of hepatic bile acid synthesis is intact in cystic fibrosis. However, the demonstration that large amounts of bile acid continue to be excreted during therapy suggests that interruption of the enterohepatic circulation continues and that deficiencies of the intraluminal phase may persist during enzyme therapy in this disease.« less

Screening for illicit drugs in pooled human urine and urinated soil samples and studies on the stability of urinary excretion products of cocaine, MDMA, and MDEA in wastewater by hyphenated mass spectrometry techniques.

PubMed

Mardal, Marie; Kinyua, Juliet; Ramin, Pedram; Miserez, Bram; Van Nuijs, Alexander L N; Covaci, Adrian; Meyer, Markus R

2017-01-01

Monitoring population drug use through wastewater-based epidemiology (WBE) is a useful method to quantitatively follow trends and estimate total drug consumption in communities. Concentrations of drug biomarkers might be low in wastewater due to dilution; and therefore analysis of pooled urine (PU) is useful to detect consumed drugs and identify targets of illicit drugs use. The aims of the study were (1) to screen PU and urinated soil (US) samples collected at festivals for illicit drug excretion products using hyphenated techniques; (2) to develop and validate a hydrophilic interaction liquid chromatography - mass spectrometry / mass spectrometry (HILIC-MS/MS) method of quantifying urinary targets of identified drugs in wastewater; and (3) to conduct a 24 h stability study, using PU and US to better reflect the chemical environment for targets in wastewater. Cocaine (COC) and ecstasy-like compounds were the most frequently detected illicit drugs; an analytical method was developed to quantify their excretion products. Hydroxymethoxymethamphetamine (HMMA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), HMMA sulfate (HMMA-S), benzoylecgonine (BE), and cocaethylene (CE) had 85-102% of initial concentration after 8 h of incubation, whereas COC and ecgonine methyl ester (EME) had 74 and 67% after 8 h, respectively. HMMA showed a net increase during 24 h of incubation (107% ± 27, n = 8), possibly due to the cleavage of HMMA conjugates, and biotransformation of MDMA. The results suggest HMMA as analytical target for MDMA consumption in WBE, due to its stability in wastewater and its excretion as the main phase I metabolite of MDMA. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

The development of a new technical platform to measure soil organic nitrogen cycling processes by microbes

NASA Astrophysics Data System (ADS)

Hu, Yuntao; Richter, Andreas; Wanek, Wolfgang

2016-04-01

Soil organic matter (SOM) decomposition is one of the most important processes of the global nitrogen cycle, having strong implications on soil N availability, terrestrial carbon cycling and soil carbon sequestration. During SOM decomposition low-molecular weight organic nitrogen (LMWON) is released which can be taken up by microbes (and plants). The breakdown of high-molecular weight organic nitrogen (HMWON, e.g. proteins, peptidoglycan, chitin, nucleic acids) represents the bottleneck of soil HMWON decomposition and is performed by extracellular enzymes released mainly by soil microorganisms. Despite that, the current understanding of the controls of these processes is incomplete. The only way to measure gross decomposition rates of these polymers is to use isotope pool dilution (IPD) techniques. In IPD approaches the product pool is isotopically enriched (by e.g. 15N) and the isotope dilution of this pool is measured over time. We have pioneered an IPD for protein and cellulose depolymerization, but IPD approaches for other polymers, specifically for important microbial necromass components such as chitin (fungi) and peptidoglycan (bacteria), or nucleic acids have not yet been developed. Here we present a workflow based on a universally applicable technical platform that allows to estimate the gross depolymerization rate of SOM (HMWON) at the molecular level, using ultra high performance liquid chromatography/high resolution Orbitrap mass spectrometry (UPLC/HRMS) combined with IPD techniques. The necessary isotopically labeled organic polymers (chitin, peptidoglycan and others) are extracted from laboratory bacterial and fungal cultures grown in fully isotopically labeled nutrient media (15N, 13C or both). A purification scheme for the different polymers is currently established. Labeled potential decomposition products (e.g. amino sugars and muropeptides from peptidoglycan, amino sugars and chitooligosaccharides from chitin, nucleotides and nucleosides from nucleic acids) are prepared by enzymatic and/or acid digestion of the polymers. Different UPLC separation columns (Hypercarb, HiliC and C18) make it possible to separate more than 100 related monomers and oligomers produced during polymer decomposition, a prerequisite for analyzing the concentrations and isotope kinetics of decomposition products in complex soil samples. The benchtop Orbitrap mass analyzer has a nominal mass resolving power of 100,000 (FWHM at m/z 200), which enables us to separate compounds that are 13C- and 15N-labelled (mass difference: 0.00632) in the same compound, allowing tracing carbon and nitrogen isotopes in the same compound in IPD experiments. With the accurate masses, retention times and the isotopic pattern we can quantify and qualify the target decomposition products and their isotope kinetics during soil incubation experiments. This will enable us to estimate in situ decomposition rates of the major organic nitrogen polymers in soils, allowing new insights into the major controls of the most important step in soil organic nitrogen recycling.

Labile pools of Pb in vegetable-growing soils investigated by an isotope dilution method and its influence on soil pH.

PubMed

Xie, Hong; Huang, Zhi-Yong; Cao, Ying-Lan; Cai, Chao; Zeng, Xiang-Cheng; Li, Jian

2012-08-01

Pollution of Pb in the surface of agricultural soils is of increasing concern due to its serious impact on the plant growth and the human health through the food chain. However, the mobility, activity and bioavailability of Pb rely mainly on its various chemical species in soils. In the present study, E and L values, the labile pools of isotopically exchangeable Pb, were estimated using the method of isotope dilution in three vegetable-growing soils. The experiments involved adding a stable enriched isotope ((206)Pb > 96%) to a soil suspension and to soils in which plants are subsequently grown, the labile pools of Pb were then estimated by measuring the isotopic composition of Pb in soil solutions and in the plant tissues, respectively. In addition, the correlation of E values and soil pH was investigated at the ranges of pH 4.5-7.0. The amount of labile Pb in soils was also estimated using different single chemical extractants and a modified BCR approach. The results showed that after spiking the enriched isotopes of (206)Pb (>96%) for 24 hours an equilibration of isotopic exchanges in soil suspensions was achieved, and the isotope ratios of (208)Pb/(206)Pb measured at that time was used for calculating the E(24 h) values. The labile pools of Pb by %E(24 h) values, ranging from 53.2% to 61.7% with an average 57%, were found to be significantly higher (p < 0.05) than the values estimated with L values, single chemical extractants and the Σ(BCR) values obtained with the BCR approach, respectively. A strong negative correlation (R(2) = 0.984) between E(24 h) values and soil pH was found in the tested soil sample. The results indicate that the %E(24 h) value can more rapidly and easily predict the labile pools of Pb in soils compared with L values, but it might be readily overestimated because of the artificial soil acidity derived from the spiked isotopic tracer and the excess of spiked enriched isotopes. The results also suggest that the amounts of Pb extracted with EDTA and the Σ(BCR) values extracted with the modified BCR approach are helpful to detect the labile pools of Pb in soils. In addition, the negative correlation between soil pH and the labile pools of Pb in soils may be useful for further remediation to reduce the bioavailability of Pb in contaminated soils.

Carotene-rich plant foods ingested with minimal dietary fat enhance the total-body vitamin A pool size in Filipino schoolchildren as assessed by stable-isotope-dilution methodology.

PubMed

Ribaya-Mercado, Judy D; Maramag, Cherry C; Tengco, Lorena W; Dolnikowski, Gregory G; Blumberg, Jeffrey B; Solon, Florentino S

2007-04-01

Strategies for improving the vitamin A status of vulnerable populations are needed. We studied the influence of the amounts of dietary fat on the effectiveness of carotene-rich plant foods in improving vitamin A status. Schoolchildren aged 9-12 y were fed standardized meals 3 times/d, 5 d/wk, for 9 wk. The meals provided 4.2 mg provitamin A carotenoids/d (mainly beta-carotene) from yellow and green leafy vegetables [carrots, pechay (bok choy), squash, and kangkong (swamp cabbage)] and 7, 15, or 29 g fat/d (2.4, 5, or 10 g fat/meal) in groups A, B, and C (n = 39, 39, and 38, respectively). Other self-selected foods eaten were recorded daily. Before and after the intervention, total-body vitamin A pool sizes and liver vitamin A concentrations were measured with the deuterated-retinol-dilution method; serum retinol and carotenoid concentrations were measured by HPLC. Similar increases in mean serum beta-carotene (5-fold), alpha-carotene (19-fold), and beta-cryptoxanthin (2-fold) concentrations; total-body vitamin A pool size (2-fold); and liver vitamin A (2-fold) concentrations were observed after 9 wk in the 3 study groups; mean serum retinol concentrations did not change significantly. The total daily beta-carotene intake from study meals plus self-selected foods was similar between the 3 groups and was 14 times the usual intake; total fat intake was 0.9, 1.4, or 2.0 times the usual intake in groups A, B, and C, respectively. The overall prevalence of low liver vitamin A (<0.07 mumol/g) decreased from 35% to 7%. Carotene-rich yellow and green leafy vegetables, when ingested with minimal fat, enhance serum carotenoids and the total-body vitamin A pool size and can restore low liver vitamin A concentrations to normal concentrations.

Measurement of bronchial blood flow in the sheep by video dilution technique.

PubMed Central

Link, D P; Parsons, G H; Lantz, B M; Gunther, R A; Green, J F; Cross, C E

1985-01-01

Bronchial blood flow was determined in five adult anaesthetised sheep by the video dilution technique. This is a new fluoroscopic technique for measuring blood flow that requires only arterial catheterisation. Catheters were placed into the broncho-oesophageal artery and ascending aorta from the femoral arteries for contrast injections and subsequent videotape recording. The technique yields bronchial blood flow as a percentage of cardiac output. The average bronchial artery blood flow was 0.6% (SD 0.20%) of cardiac output. In one sheep histamine (90 micrograms) injected directly into the bronchial artery increased bronchial blood flow by a factor of 6 and histamine (90 micrograms) plus methacholine (4.5 micrograms) augmented flow by a factor of 7.5 while leaving cardiac output unchanged. This study confirms the high degree of reactivity of the bronchial circulation and demonstrates the feasibility of using the video dilution technique to investigate the determinants of total bronchial artery blood flow in a stable animal model avoiding thoracotomy. Images PMID:3883564

Isolation of a hyperthermophilic archaeum predicted by in situ RNA analysis.

PubMed

Huber, R; Burggraf, S; Mayer, T; Barns, S M; Rossnagel, P; Stetter, K O

1995-07-06

A variety of hyperthermophilic bacteria and archaea have been isolated from high-temperature environments by plating and serial dilutions. However, these techniques allow only the small percentage of organisms able to form colonies, or those that are predominant within environmental samples, to be obtained in pure culture. Recently, in situ 16S ribosomal RNA analyses of samples from the Obsidian hot pool at Yellowstone National Park, Wyoming, revealed a variety of archaeal sequences, which were all different from those of previously isolated species. This suggests substantial diversity of archaea with so far unknown morphological, physiological and biochemical features, which may play an important part within high-temperature ecosystems. Here we describe a procedure to obtain pure cultures of unknown organisms harbouring specific 16S rRNA sequences identified previously within the environment. It combines visual recognition of single cells by phylogenetic staining and cloning by 'optical tweezers'. Our result validates polymerase chain reaction data on the existence of large archael communities.

World Health Organization International Standard to harmonize assays for detection of hepatitis E virus RNA.

PubMed

Baylis, Sally A; Blümel, Johannes; Mizusawa, Saeko; Matsubayashi, Keiji; Sakata, Hidekatsu; Okada, Yoshiaki; Nübling, C Micha; Hanschmann, Kay-Martin O

2013-05-01

Nucleic acid amplification technique-based assays are a primary method for the detection of acute hepatitis E virus (HEV) infection, but assay sensitivity can vary widely. To improve interlaboratory results for the detection and quantification of HEV RNA, a candidate World Health Organization (WHO) International Standard (IS) strain was evaluated in a collaborative study involving 23 laboratories from 10 countries. The IS, code number 6329/10, was formulated by using a genotype 3a HEV strain from a blood donation, diluted in pooled human plasma and lyophilized. A Japanese national standard, representing a genotype 3b HEV strain, was prepared and evaluated in parallel. The potencies of the standards were determined by qualitative and quantitative assays. Assay variability was substantially reduced when HEV RNA concentrations were expressed relative to the IS. Thus, WHO has established 6329/10 as the IS for HEV RNA, with a unitage of 250,000 International Units per milliliter.

Potential for Waste Stratification from Back-Dilution in Tank 241-SY-101

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

Antoniak, Z.I.; Meyer, P.A.

Since late 1997, the floating crust layer in Hanford Tank 241-SY-101 (SY-101) has grown about two meters by gas accumulation. To reverse crust growth and reduce its retained gas volume, the waste in SY-101 will be diluted by transferring at least 300,000 gal of waste out of the tank and replacing it with water. In the fall of 1999, approximately 100,000 gal of this waste will be transferred into Tank SY-102; within a few days of that initial transfer, approximately 100,000 gal of water will be added to SY-101. This initial back-dilution is being planned to ensure that the basemore » of the floating crust layer will be lifted away from the mixer pump inlet with minimal effect on the crust itself. The concern is that the added water will pool under the crust, so the resulting fluid mixture will be too light to lift the crust away from the mixer pump and dissolution at the crust base could cause unwanted gas release. To ensure sufficient mixing to prevent such stratification, water will be added near the tank bottom either through an existing sparge ring on the base of the mixer pump or through the dilution line at the inlet of the transfer pump. A number of simulations using the TEMPEST code showed that the mixing of the water and waste by this method is rapid, and the water does not pool under the crust. Although a density gradient is present, its magnitude is small compared with the difference between the slurry and water density. The result is essentially the same whether water is introduced at the base of the mixer pump or at the transfer pump. There is little effect of water flowrate up to the 500 gpm studied. In all cases, the minimum density remained above that required to float the crust and well above the density of saturated liquid. This indicates that the base of the crust will rise during back-dilution and there will be little or no dissolution of the crust base because the water will be close to saturation from the dissolution of solids in the mixed slurry.« less

Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans

PubMed Central

Walker, Ann C.; O'Connor-Semmes, Robin L.; Leonard, Michael S.; Miller, Ram R.; Stimpson, Stephen A.; Turner, Scott M.; Ravussin, Eric; Cefalu, William T.; Hellerstein, Marc K.; Evans, William J.

2014-01-01

Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses [n = 35: 20 men (19–30 yr, 70–84 yr), 15 postmenopausal women (51–62 yr, 70–84 yr)] were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r = 0.868, P < 0.0001), with less bias compared with lean body mass assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total lean body mass assessment by DXA. PMID:24764133

Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans.

PubMed

Clark, Richard V; Walker, Ann C; O'Connor-Semmes, Robin L; Leonard, Michael S; Miller, Ram R; Stimpson, Stephen A; Turner, Scott M; Ravussin, Eric; Cefalu, William T; Hellerstein, Marc K; Evans, William J

2014-06-15

Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses [n = 35: 20 men (19-30 yr, 70-84 yr), 15 postmenopausal women (51-62 yr, 70-84 yr)] were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r = 0.868, P < 0.0001), with less bias compared with lean body mass assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total lean body mass assessment by DXA. Copyright © 2014 the American Physiological Society.

A Sequential Leach Method and Pb Isotope Approach to Studying Apatite Weathering in Granitoid Soils at Hubbard Brook Experimental Forest, NH, USA

NASA Astrophysics Data System (ADS)

Nezat, C. A.; Blum, J. D.

2005-12-01

Easily dissolved minerals such as calcite and apatite can be important in controlling stream and ground water chemistry even though these minerals are only present in trace amounts in granitoid rocks. Because of its solubility, apatite, a calcium phosphate mineral, may be a significant source of essential nutrients (especially phosphorous) for vegetation, and has been shown to strongly influence stream and soil water composition (e.g, calcium, strontium and rare earth elements). There are additional sources of Ca (e.g., feldspars, hornblende) and P (e.g., organic matter or bound to Fe and Al oxides) in granitoid soils. In order to distinguish the chemical constituents of apatite from other pools in the bulk soil, we selectively dissolved apatite with a dilute acid leach, and measured Pb isotopic ratios of apatite, feldspar, and leachates. We tested the leaching procedure on mineral separates and verified that a dilute nitric solution primarily dissolves apatite. Silicates were dissolved in subsequent steps by successively stronger acids. We then applied this method to bulk soils collected from several soil pits across a small watershed at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA, to determine the spatial distribution of Ca and P pools, and determine the depth of apatite depletion in the soil. We also measured Pb isotope ratios in the soil leachates to distinguish among the various sources of Pb (e.g., apatite, feldspars and anthropogenic sources). We found that Pb in the dilute nitric leach of the HBEF organic soils is dominated by anthropogenic sources and that Pb from apatite becomes increasingly important with depth.

A new hammer to crack an old nut: interspecific competitive resource capture by plants is regulated by nutrient supply, not climate.

PubMed

Trinder, Clare J; Brooker, Rob W; Davidson, Hazel; Robinson, David

2012-01-01

Although rarely acknowledged, our understanding of how competition is modulated by environmental drivers is severely hampered by our dependence on indirect measurements of outcomes, rather than the process of competition. To overcome this, we made direct measurements of plant competition for soil nitrogen (N). Using isotope pool-dilution, we examined the interactive effects of soil resource limitation and climatic severity between two common grassland species. Pool-dilution estimates the uptake of total N over a defined time period, rather than simply the uptake of ¹⁵N label, as used in most other tracer experiments. Competitive uptake of N was determined by its available form (NO₃⁻ or NH₄⁺). Soil N availability had a greater effect than the climatic conditions (location) under which plants grew. The results did not entirely support either of the main current theories relating the role of competition to environmental conditions. We found no evidence for Tilman's theory that competition for soil nutrients is stronger at low, compared with high nutrient levels and partial support for Grime's theory that competition for soil nutrients is greater under potentially more productive conditions. These results provide novel insights by demonstrating the dynamic nature of plant resource competition.

A New Hammer to Crack an Old Nut: Interspecific Competitive Resource Capture by Plants Is Regulated by Nutrient Supply, Not Climate

PubMed Central

Trinder, Clare J.; Brooker, Rob W.; Davidson, Hazel; Robinson, David

2012-01-01

Although rarely acknowledged, our understanding of how competition is modulated by environmental drivers is severely hampered by our dependence on indirect measurements of outcomes, rather than the process of competition. To overcome this, we made direct measurements of plant competition for soil nitrogen (N). Using isotope pool-dilution, we examined the interactive effects of soil resource limitation and climatic severity between two common grassland species. Pool-dilution estimates the uptake of total N over a defined time period, rather than simply the uptake of 15N label, as used in most other tracer experiments. Competitive uptake of N was determined by its available form (NO3 − or NH4 +). Soil N availability had a greater effect than the climatic conditions (location) under which plants grew. The results did not entirely support either of the main current theories relating the role of competition to environmental conditions. We found no evidence for Tilman's theory that competition for soil nutrients is stronger at low, compared with high nutrient levels and partial support for Grime's theory that competition for soil nutrients is greater under potentially more productive conditions. These results provide novel insights by demonstrating the dynamic nature of plant resource competition. PMID:22247775

A field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS).

PubMed

Van Campenhout, Karen; Goenaga Infante, Heidi; Goemans, Geert; Belpaire, Claude; Adams, Freddy; Blust, Ronny; Bervoets, Lieven

2008-05-15

The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals. The distribution of the metals Cd, Cu, Ni, Pb and Zn among cytosolic fractions displayed strong differences. The cytosolic concentration of Cd, Ni and Pb increased proportionally with the total liver levels. However, the cytosolic concentrations of Cu and Zn only increased above a certain liver tissue threshold level. Cd, Cu and Zn, but not Pb and Ni, were largely associated with the MT pool in correspondence with the environmental exposure and liver tissue concentrations. Most of the Pb and Ni and a considerable fraction of Cu and Zn, but not Cd, were associated to High Molecular Weight (HMW) fractions. The relative importance of the Cu and Zn in the HMW fraction decreased with increasing contamination levels while the MT pool became progressively more important. The close relationship between the cytosolic metal load and the total MT levels or the metals bound on the MT pool indicates that the metals, rather than other stress factors, are the major factor determining MT induction.

Freeze-dried plasma enhances clot formation and inhibits fibrinolysis in the presence of tissue plasminogen activator similar to pooled liquid plasma.

PubMed

Huebner, Benjamin R; Moore, Ernest E; Moore, Hunter B; Sauaia, Angela; Stettler, Gregory; Dzieciatkowska, Monika; Hansen, Kirk; Banerjee, Anirban; Silliman, Christopher C

2017-08-01

Systemic hyperfibrinolysis is an integral part of trauma-induced coagulopathy associated with uncontrolled bleeding. Recent data suggest that plasma-first resuscitation attenuates hyperfibrinolysis; however, the availability, transport, storage, and administration of plasma in austere environments remain challenging and have limited its use. Freeze-dried plasma (FDP) is a potential alternative due to ease of storage, longer shelf life, and efficient reconstitution. FDP potentially enhances clot formation and resists breakdown better than normal saline (NS) and albumin and similar to liquid plasma. Healthy volunteers underwent citrated blood draw followed by 50% dilution with NS, albumin, pooled plasma (PP), or pooled freeze-dried plasma (pFDP). Citrated native and tissue plasminogen activator (t-PA)-challenge (75 ng/mL) thrombelastography were done. Proteins in PP, pFDP, and albumin were analyzed by mass spectroscopy. pFDP and PP had superior clot-formation rates (angle) and clot strength (maximum amplitude) compared with NS and albumin in t-PA-challenge thrombelastographies (angle: pFDP, 67.9 degrees; PP, 67.8 degrees; NS, 40.6 degrees; albumin, 35.8 degrees; maximum amplitude: pFDP, 62.4 mm; PP, 63.5 mm; NS, 44.8 mm; albumin, 41.1 mm). NS and albumin dilution increased susceptibility to t-PA-induced hyperfibrinolysis compared with pFDP and PP (NS, 62.4%; albumin, 62.6%; PP, 8.5%; pFDP, 6.7%). pFDP was similar to PP in the attenuation of t-PA-induced fibrinolysis. Most proteins (97%) were conserved during the freeze-dry process, with higher levels in 12% of pFDP proteins compared with PP. pFDP enhances clot formation and attenuates hyperfibrinolysis better than NS and albumin and is a potential alternative to plasma resuscitation in the treatment of hemorrhagic shock. © 2017 AABB.

Mechanistic investigations in sono-hybrid techniques for rice straw pretreatment.

PubMed

Suresh, Kelothu; Ranjan, Amrita; Singh, Shuchi; Moholkar, Vijayanand S

2014-01-01

This paper reports comparative study of two chemical techniques (viz. dilute acid/alkali treatment) and two physical techniques (viz. hot water bath and autoclaving) coupled with sonication, termed as sono-hybrid techniques, for hydrolysis of rice straw. The efficacy of each sono-hybrid technique was assessed on the basis of total sugar and reducing sugar release. The system of biomass pretreatment is revealed to be mass transfer controlled. Higher sugar release is obtained during dilute acid treatment than dilute alkali treatment. Autoclaving alone was found to increase sugar release marginally as compared to hot water bath. Sonication of the biomass solution after autoclaving and stirring resulted in significant rise of sugar release, which is attributed to strong convection generated during sonication that assists effective transport of sugar molecules. Discrimination between individual contributions of ultrasound and cavitation to mass transfer enhancement reveals that contribution of ultrasound (through micro-streaming) is higher. Micro-turbulence as well as acoustic waves generated by cavitation did not contribute much to enhancing of mass transfer in the system. Copyright © 2013 Elsevier B.V. All rights reserved.

Principles, performance, and applications of spectral reconstitution (SR) in quantitative analysis of oils by Fourier transform infrared spectroscopy (FT-IR).

PubMed

García-González, Diego L; Sedman, Jacqueline; van de Voort, Frederik R

2013-04-01

Spectral reconstitution (SR) is a dilution technique developed to facilitate the rapid, automated, and quantitative analysis of viscous oil samples by Fourier transform infrared spectroscopy (FT-IR). This technique involves determining the dilution factor through measurement of an absorption band of a suitable spectral marker added to the diluent, and then spectrally removing the diluent from the sample and multiplying the resulting spectrum to compensate for the effect of dilution on the band intensities. The facsimile spectrum of the neat oil thus obtained can then be qualitatively or quantitatively analyzed for the parameter(s) of interest. The quantitative performance of the SR technique was examined with two transition-metal carbonyl complexes as spectral markers, chromium hexacarbonyl and methylcyclopentadienyl manganese tricarbonyl. The estimation of the volume fraction (VF) of the diluent in a model system, consisting of canola oil diluted to various extents with odorless mineral spirits, served as the basis for assessment of these markers. The relationship between the VF estimates and the true volume fraction (VF(t)) was found to be strongly dependent on the dilution ratio and also depended, to a lesser extent, on the spectral resolution. These dependences are attributable to the effect of changes in matrix polarity on the bandwidth of the ν(CO) marker bands. Excellent VF(t) estimates were obtained by making a polarity correction devised with a variance-spectrum-delineated correction equation. In the absence of such a correction, SR was shown to introduce only a minor and constant bias, provided that polarity differences among all the diluted samples analyzed were minimal. This bias can be built into the calibration of a quantitative FT-IR analytical method by subjecting appropriate calibration standards to the same SR procedure as the samples to be analyzed. The primary purpose of the SR technique is to simplify preparation of diluted samples such that only approximate proportions need to be adhered to, rather than using exact weights or volumes, the marker accounting for minor variations. Additional applications discussed include the use of the SR technique in extraction-based, quantitative, automated FT-IR methods for the determination of moisture, acid number, and base number in lubricating oils, as well as of moisture content in edible oils.

Frozen gene pools - A future for species otherwise destined for extinction

USGS Publications Warehouse

Gee, G.F.

1986-01-01

Conclusion: Semen banks and ova and embryo banks can be practical methods to maintain gene pools. Gene pool preservation is desperately needed today due to the rapid decline in number of species and their habitat, a matter that is of concern to.biologists, economists, and politicians worldwide. Techniques are available for the cryopreservation of semen from many animals (and embryos from a few mammals) and adaptations of these techniques to other animals should be possible. A frozen gene pool in conjunction with existing programs makes it possible to preserve gene pools at less cost or in.some cases where no other alternative to extinction existed.

Measurement of LNAPL flow using single-well tracer dilution techniques.

PubMed

Sale, Tom; Taylor, Geoffrey Ryan; Iltis, Gabriel; Lyverse, Mark

2007-01-01

This paper describes the use of single-well tracer dilution techniques to resolve the rate of light nonaqueous phase liquid (LNAPL) flow through wells and the adjacent geologic formation. Laboratory studies are presented in which a fluorescing tracer is added to LNAPL in wells. An in-well mixer keeps the tracer well mixed in the LNAPL. Tracer concentrations in LNAPL are measured through time using a fiber optic cable and a spectrometer. Results indicate that the rate of tracer depletion is proportional to the rate of LNAPL flow through the well and the adjacent formation. Tracer dilution methods are demonstrated for vertically averaged LNAPL Darcy velocities of 0.00048 to 0.11 m/d and LNAPL thicknesses of 9 to 24 cm. Over the range of conditions studied, results agree closely with steady-state LNAPL flow rates imposed by pumping. A key parameter for estimating LNAPL flow rates in the formation is the flow convergence factor alpha. Measured convergence factors for 0.030-inch wire wrap, 0.030-inch-slotted polyvinyl chloride (PVC), and 0.010-inch-slotted PVC are 1.7, 0.91, and 0.79, respectively. In addition, methods for using tracer dilution data to determine formation transmissivity to LNAPL are presented. Results suggest that single-well tracer dilution techniques are a viable approach for measuring in situ LNAPL flow and formation transmissivity to LNAPL.

Quantitative Analysis by Isotopic Dilution Using Mass Spectroscopy: The Determination of Caffeine by GC-MS.

ERIC Educational Resources Information Center

Hill, Devon W.; And Others

1988-01-01

Describes a laboratory technique for quantitative analysis of caffeine by an isotopic dilution method for coupled gas chromatography-mass spectroscopy. Discusses caffeine analysis and experimental methodology. Lists sample caffeine concentrations found in common products. (MVL)

Body Composition of Bangladeshi Children: Comparison and Development of Leg-to-Leg Bioelectrical Impedance Equation

PubMed Central

Khan, I.; Hawlader, Sophie Mohammad Delwer Hossain; Arifeen, Shams El; Moore, Sophie; Hills, Andrew P.; Wells, Jonathan C.; Persson, Lars-Åke; Kabir, Iqbal

2012-01-01

The aim of this study was to investigate the validity of the Tanita TBF 300A leg-to-leg bioimpedance analyzer for estimating fat-free mass (FFM) in Bangladeshi children aged 4-10 years and to develop novel prediction equations for use in this population, using deuterium dilution as the reference method. Two hundred Bangladeshi children were enrolled. The isotope dilution technique with deuterium oxide was used for estimation of total body water (TBW). FFM estimated by Tanita was compared with results of deuterium oxide dilution technique. Novel prediction equations were created for estimating FFM, using linear regression models, fitting child's height and impedance as predictors. There was a significant difference in FFM and percentage of body fat (BF%) between methods (p<0.01), Tanita underestimating TBW in boys (p=0.001) and underestimating BF% in girls (p<0.001). A basic linear regression model with height and impedance explained 83% of the variance in FFM estimated by deuterium oxide dilution technique. The best-fit equation to predict FFM from linear regression modelling was achieved by adding weight, sex, and age to the basic model, bringing the adjusted R2 to 89% (standard error=0.90, p<0.001). These data suggest Tanita analyzer may be a valid field-assessment technique in Bangladeshi children when using population-specific prediction equations, such as the ones developed here. PMID:23082630

Sparse feature learning for instrument identification: Effects of sampling and pooling methods.

PubMed

Han, Yoonchang; Lee, Subin; Nam, Juhan; Lee, Kyogu

2016-05-01

Feature learning for music applications has recently received considerable attention from many researchers. This paper reports on the sparse feature learning algorithm for musical instrument identification, and in particular, focuses on the effects of the frame sampling techniques for dictionary learning and the pooling methods for feature aggregation. To this end, two frame sampling techniques are examined that are fixed and proportional random sampling. Furthermore, the effect of using onset frame was analyzed for both of proposed sampling methods. Regarding summarization of the feature activation, a standard deviation pooling method is used and compared with the commonly used max- and average-pooling techniques. Using more than 47 000 recordings of 24 instruments from various performers, playing styles, and dynamics, a number of tuning parameters are experimented including the analysis frame size, the dictionary size, and the type of frequency scaling as well as the different sampling and pooling methods. The results show that the combination of proportional sampling and standard deviation pooling achieve the best overall performance of 95.62% while the optimal parameter set varies among the instrument classes.

Technical success, technique efficacy and complications of minimally-invasive imaging-guided percutaneous ablation procedures of breast cancer: A systematic review and meta-analysis.

PubMed

Mauri, Giovanni; Sconfienza, Luca Maria; Pescatori, Lorenzo Carlo; Fedeli, Maria Paola; Alì, Marco; Di Leo, Giovanni; Sardanelli, Francesco

2017-08-01

To systematically review studies concerning imaging-guided minimally-invasive breast cancer treatments. An online database search was performed for English-language articles evaluating percutaneous breast cancer ablation. Pooled data and 95% confidence intervals (CIs) were calculated. Technical success, technique efficacy, minor and major complications were analysed, including ablation technique subgroup analysis and effect of tumour size on outcome. Forty-five studies were analysed, including 1,156 patients and 1,168 lesions. Radiofrequency (n=577; 50%), microwaves (n=78; 7%), laser (n=227; 19%), cryoablation (n=156; 13%) and high-intensity focused ultrasound (HIFU, n=129; 11%) were used. Pooled technical success was 96% (95%CI 94-97%) [laser=98% (95-99%); HIFU=96% (90-98%); radiofrequency=96% (93-97%); cryoablation=95% (90-98%); microwave=93% (81-98%)]. Pooled technique efficacy was 75% (67-81%) [radiofrequency=82% (74-88); cryoablation=75% (51-90); laser=59% (35-79); HIFU=49% (26-74)]. Major complications pooled rate was 6% (4-8). Minor complications pooled rate was 8% (5-13%). Differences between techniques were not significant for technical success (p=0.449), major complications (p=0.181) or minor complications (p=0.762), but significant for technique efficacy (p=0.009). Tumour size did not impact on variables (p>0.142). Imaging-guided percutaneous ablation techniques of breast cancer have a high rate of technical success, while technique efficacy remains suboptimal. Complication rates are relatively low. • Imaging-guided ablation techniques for breast cancer are 96% technically successful. • Overall technique efficacy rate is 75% but largely inhomogeneous among studies. • Overall major and minor complication rates are low (6-8%).

Experimental study of heat and mass transfer in a buoyant countercurrent exchange flow

NASA Astrophysics Data System (ADS)

Conover, Timothy Allan

Buoyant Countercurrent Exchange Flow occurs in a vertical vent through which two miscible fluids communicate, the higher-density fluid, residing above the lower-density fluid, separated by the vented partition. The buoyancy- driven zero net volumetric flow through the vent transports any passive scalars, such as heat and toxic fumes, between the two compartments as the fluids seek thermodynamic and gravitational equilibrium. The plume rising from the vent into the top compartment resembles a pool fire plume. In some circumstances both countercurrent flows and pool fires can ``puff'' periodically, with distinct frequencies. One experimental test section containing fresh water in the top compartment and brine (NaCl solution) in the bottom compartment provided a convenient, idealized flow for study. This brine flow decayed in time as the concentrations approached equilibrium. A second test section contained fresh water that was cooled by heat exchangers above and heated by electrical elements below and operated steadily, allowing more time for data acquisition. Brine transport was reduced to a buoyancy- scaled flow coefficient, Q*, and heat transfer was reduced to an analogous coefficient, H*. Results for vent diameter D = 5.08 cm were consistent between test sections and with the literature. Some results for D = 2.54 cm were inconsistent, suggesting viscosity and/or molecular diffusion of heat become important at smaller scales. Laser Doppler Velocimetry was used to measure velocity fields in both test sections, and in thermal flow a small thermocouple measured temperature simultaneously with velocity. Measurement fields were restricted to the plume base region, above the vent proper. In baseline periodic flow, instantaneous velocity and temperature were ensemble averaged, producing a movie of the average variation of each measure during a puffing flow cycle. The temperature movie revealed the previously unknown cold core of the puff during its early development. The renewal-length model for puffing frequency of pool fire plumes was extended to puffing countercurrent flows by estimating inflow dilution. Puffing frequencies at several conditions were reduced to Strouhal number based on dilute plume density. Results for D = 5.08 cm compared favorably to published measurements of puffing pool fires, suggesting that the two different flows obey the same periodic dynamic process.

The influence of dilution on the offline measurement of exhaled nitric oxide.

PubMed

MacBean, Victoria; Pooranampillai, Dharmika; Howard, Catherine; Lunt, Alan; Greenough, Anne

2018-02-26

Measurement of fractional exhaled nitric oxide (FeNO) is used to determine the presence and severity of eosinophilic airway inflammation in asthma and other wheezing illnesses. The gold standard of online measurement during a single prolonged exhalation is not suitable for use in young children. The international guidelines for offline measurements recommend collection of exhaled gas in an appropriate reservoir for later analysis in young children. The apparatus required for gas collection, however, creates dead space within the system, which may result in sample dilution and hence inaccuracy. Our objective was to investigate the effect such dilution might have on the accuracy of offline FeNO by comparing the results to online results. Thirty-five adult subjects without respiratory disease underwent online measurement of FeNO and, thereafter, undertook offline FeNO measurements via exhalation into a collection reservoir using one, five or ten inhalation-exhalation cycles. Fifteen of the subjects also exhaled using the five-breath technique via apparatus with additional dead space. An equation incorporating dead space volume and the number of breaths was used to predict the degree of dilution; the predicted results were compared to the measured results. The median (IQR) FeNO from a one-breath technique (22 (15-28) ppb was not significantly different to online values (19 (12-27) ppb, p  =  1.00), but the results from the five-breath technique (11 (4-19) ppb, p  <  0.0001), the ten-breath technique (6 (4-15) ppb, p  <  0.0001) and the additional dead space experiment (6 (3-8) ppb, p  =  0.0006) were significantly lower than online FeNO. Measured values were consistently significantly different to those predicted by the dilution equation, even when incorporating the exact exhaled volume of gas. Offline FeNO results may be inaccurate when subjects are unable to fill the collection reservoir with a single exhalation, thus the technique may not be suitable for preschool children.

An evaluation of population index and estimation techniques for tadpoles in desert pools

USGS Publications Warehouse

Jung, Robin E.; Dayton, Gage H.; Williamson, Stephen J.; Sauer, John R.; Droege, Sam

2002-01-01

Using visual (VI) and dip net indices (DI) and double-observer (DOE), removal (RE), and neutral red dye capture-recapture (CRE) estimates, we counted, estimated, and censused Couch's spadefoot (Scaphiopus couchii) and canyon treefrog (Hyla arenicolor) tadpole populations in Big Bend National Park, Texas. Initial dye experiments helped us determine appropriate dye concentrations and exposure times to use in mesocosm and field trials. The mesocosm study revealed higher tadpole detection rates, more accurate population estimates, and lower coefficients of variation among pools compared to those from the field study. In both mesocosm and field studies, CRE was the best method for estimating tadpole populations, followed by DOE and RE. In the field, RE, DI, and VI often underestimated populations in pools with higher tadpole numbers. DI improved with increased sampling. Larger pools supported larger tadpole populations, and tadpole detection rates in general decreased with increasing pool volume and surface area. Hence, pool size influenced bias in tadpole sampling. Across all techniques, tadpole detection rates differed among pools, indicating that sampling bias was inherent and techniques did not consistently sample the same proportion of tadpoles in each pool. Estimating bias (i.e., calculating detection rates) therefore was essential in assessing tadpole abundance. Unlike VI and DOE, DI, RE, and CRE could be used in turbid waters in which tadpoles are not visible. The tadpole population estimates we used accommodated differences in detection probabilities in simple desert pool environments but may not work in more complex habitats.

Mechanisms for retention of bioavailable nitrogen in volcanic rainforest soils

NASA Astrophysics Data System (ADS)

Huygens, Dries; Boeckx, Pascal; Templer, Pamela; Paulino, Leandro; van Cleemput, Oswald; Oyarzún, Carlos; Müller, Christoph; Godoy, Roberto

2008-08-01

Nitrogen cycling is an important aspect of forest ecosystem functioning. Pristine temperate rainforests have been shown to produce large amounts of bioavailable nitrogen, but despite high nitrogen turnover rates, loss of bioavailable nitrogen is minimal in these ecosystems. This tight nitrogen coupling is achieved through fierce competition for bioavailable nitrogen by abiotic processes, soil microbes and plant roots, all of which transfer bioavailable nitrogen to stable nitrogen sinks, such as soil organic matter and above-ground forest vegetation. Here, we use a combination of in situ 15N isotope dilution and 15N tracer techniques in volcanic soils of a temperate evergreen rainforest in southern Chile to further unravel retention mechanisms for bioavailable nitrogen. We find three processes that contribute significantly to nitrogen bioavailability in rainforest soils: heterotrophic nitrate production, nitrate turnover into ammonium and into a pool of dissolved organic nitrogen that is not prone to leaching loss, and finally, the decoupling of dissolved inorganic nitrogen turnover and leaching losses of dissolved organic nitrogen. Identification of these biogeochemical processes helps explain the retention of bioavailable nitrogen in pristine temperate rainforests.

Quantification of isotope-labelled and unlabelled folates in plasma, ileostomy and food samples.

PubMed

Büttner, Barbara E; Öhrvik, Veronica E; Witthöft, Cornelia M; Rychlik, Michael

2011-01-01

New stable isotope dilution assays were developed for the simultaneous quantitation of [(13)C(5)]-labelled and unlabelled 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid, folic acid along with unlabelled tetrahydrofolic acid and 10-formylfolic acid in clinical samples deriving from human bioavailability studies, i.e. plasma, ileostomy samples, and food. The methods were based on clean-up by strong anion exchange followed by LC-MS/MS detection. Deuterated analogues of the folates were applied as the internal standards in the stable isotope dilution assays. Assay sensitivity was sufficient to detect all relevant folates in the respective samples as their limits of detection were below 0.62 nmol/L in plasma and below 0.73 μg/100 g in food or ileostomy samples. Quantification of the [(13)C(5)]-label in clinical samples offers the possibility to differentiate between folate from endogenous body pools and the administered dose when executing bioavailability trials.

Compositional analysis of dilute nitride doped indium antimonide bulk crystal by VDS technique

NASA Astrophysics Data System (ADS)

Deshpande, Manisha; Maske, Dilip; Choudhari, Rashmi; Arora, Brij Mohan; Gadkari, Dattatray

2016-05-01

Dilute nitrides are suitable materials for fabrication of devices in detection of long wavelength infrared region. Dilute nitride doped Indium antimonide bulk crystals were grown using vertical directional solidification technique. The compositional characteristics of the crystals were carried out using EDS. The analysis was simulated and compared with observations using DTSA II software for accuracy. The ingots have uniform composition of Indium and Antimony. The actual nitrogen composition measured using EDS was 0.136% for doped nitrogen composition 0.1% except near conical end where it was 0.1%. The study of bonding between nitrogen, Indium and antimony was carried out using SIMS. The analysis shows strong presence of In-N bonding along with In-Sb bonds which indicates nitrogen has replaced antimony atoms in crystal lattice.

Videodensitometric Methods for Cardiac Output Measurements

NASA Astrophysics Data System (ADS)

Mischi, Massimo; Kalker, Ton; Korsten, Erik

2003-12-01

Cardiac output is often measured by indicator dilution techniques, usually based on dye or cold saline injections. Developments of more stable ultrasound contrast agents (UCA) are leading to new noninvasive indicator dilution methods. However, several problems concerning the interpretation of dilution curves as detected by ultrasound transducers have arisen. This paper presents a method for blood flow measurements based on UCA dilution. Dilution curves are determined by real-time densitometric analysis of the video output of an ultrasound scanner and are automatically fitted by the Local Density Random Walk model. A new fitting algorithm based on multiple linear regression is developed. Calibration, that is, the relation between videodensity and UCA concentration, is modelled by in vitro experimentation. The flow measurement system is validated by in vitro perfusion of SonoVue contrast agent. The results show an accurate dilution curve fit and flow estimation with determination coefficient larger than 0.95 and 0.99, respectively.

Hardness, microstructure and surface characterization of laser gas nitrided commercially pure titanium using high power CO{sub 2} laser

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

Selvan, J.S.; Subramanian, K.; Nath, A.K.

Surface nitriding of commercially pure (CP) titanium was carried out using high power CO{sub 2} laser at pure nitrogen and dilute nitrogen (N{sub 2} + Ar) environment. The hardness, microstructure, and melt pool configuration of the laser melted titanium in helium and argon atmosphere was compared with laser melting at pure and dilute nitrogen environment. The hardness of the nitrided layer was of the order of 1000 to 1600 HV. The hardness of the laser melted titanium in the argon and helium atmosphere was 500 to 1000 HV. Using x-ray analysis of the formation of TiN and Ti{sub 2}N phasemore » was identified in the laser nitrided titanium. The presence of nitrogen in the nitrided zone was confirmed using secondary ion mass spectroscopy (SIMS) analysis. The microstructures revealed densely populated dendrites in the sample nitrided at 100% N{sub 2} environment and thinly populated dendrites in dilute environment. The crack intensity was large in the nitrided sample at pure nitrogen, and few cracks were observed in the 50% N{sub 2} + 50% Ar environment.« less

The Indo-Pacific Warm Pool: critical to world oceanography and world climate

NASA Astrophysics Data System (ADS)

De Deckker, Patrick

2016-12-01

The Indo-Pacific Warm Pool holds a unique place on the globe. It is a large area [>30 × 106 km2] that is characterised by permanent surface temperature >28 °C and is therefore called the `heat engine' of the globe. High convective clouds which can reach altitudes up to 15 km generate much latent heat in the process of convection and this area is therefore called the `steam engine' of the world. Seasonal and contrasting monsoonal activity over the region is the cause for a broad seasonal change of surface salinities, and since the area lies along the path of the Great Ocean Conveyor Belt, it is coined the `dilution' basin due to the high incidence of tropical rain and, away from the equator, tropical cyclones contribute to a significant drop in sea water salinity. Discussion about what may happen in the future of the Warm Pool under global warming is presented together with a description of the Warm Pool during the past, such as the Last Glacial Maximum when sea levels had dropped by ~125 m. A call for urgent monitoring of the IPWP area is justified on the grounds of the significance of this area for global oceanographic and climatological processes, but also because of the concerned threats to human population living there.

Phase-field simulation of weld solidification microstructure in an Al Cu alloy

NASA Astrophysics Data System (ADS)

Farzadi, A.; Do-Quang, M.; Serajzadeh, S.; Kokabi, A. H.; Amberg, G.

2008-09-01

Since the mechanical properties and the integrity of the weld metal depend on the solidification behaviour and the resulting microstructural characteristics, understanding weld pool solidification is of importance to engineers and scientists. Thermal and fluid flow conditions affect the weld pool geometry and solidification parameters. During solidification of the weld pool, a columnar grain structure develops in the weld metal. Prediction of the formation of the microstructure during welding may be an important and supporting factor for technology optimization. Nowadays, increasing computing power allows direct simulations of the dendritic and cell morphology of columnar grains in the molten zone for specific temperature conditions. In this study, the solidification microstructures of the weld pool at different locations along the fusion boundary are simulated during gas tungsten arc welding of Al-3wt%Cu alloy using the phase-field model for the directional solidification of dilute binary alloys. A macroscopic heat transfer and fluid flow model was developed to assess the solidification parameters, notably the temperature gradient and solidification growth rate. The effect of the welding speed is investigated. Computer simulations of the solidification conditions and the formation of a cellular morphology during the directional solidification in gas tungsten arc welding are described. Moreover, the simulation results are compared with existing theoretical models and experimental findings.

Immunologic Approach to the Identification and Development of Vaccines to Various Toxins

DTIC Science & Technology

1992-04-20

0.05 ml of a 1:2500 dilution of goat anti-mouse Ig conjugated to horse radish peroxidase (HRP, Fisher Scientific, Orangeburg, NY) were added to the...mouse immune sera were pooled and adsorbed over a normal horse IgG-agarose column. Normal horse 1gG was used because normal burro IgG is not readily...available, and because the horse is proba- bly the closest species to the burro in evolutionary terms. The adsorbed mouse sera were tested in ELISA

Comparison of candidate vCJD in vitro diagnostic assays using identical sample sets.

PubMed

Cooper, J K; Ladhani, K; Minor, P

2012-02-01

With four transfusion related transmissions of variant Creutzfeldt-Jakob Disease (vCJD), three of which developed clinical disease and the other died of other causes but was positive for markers of infection, there is an increased urgency to identify and implement a test for blood donor screening. With limited amounts of blood samples from vCJD cases available test evaluation is challenging. Alternative approaches are therefore needed. Control and vCJD tissues homogenates, where levels of markers of infectivity are known, were sequentially diluted in pooled human plasma. Identical sets of samples were provided blind to research groups developing diagnostic tests for vCJD; identical sample sets allows for direct comparisons of sensitivity to be made. Control and vCJD tissue homogenates were sequentially diluted in pooled human plasma (detergent solvent treated or cryo-depleted) supplied by commercial fractionators. Dilutions of vCJD tissues were within and beyond the limits of detection previously determined by the conformation-dependent immunoassay (Cooper et al.: Vox Sang 2007;92:302-310; Bellon et al.: J Gen Virol 2003;84: 1921-1925). A number of methods were used for the analysis of the blinded panels; with background signal from the normal prion protein (PrP) being removed by digestion with proteinase, epitope protection or selective capture of PrP(tse). Assay sensitivities were directly compared using identical sample sets. This approach identified several transmissible spongiform encephalopathies (TSE) diagnostic tests, based on different principles, high in analytical sensitivity that reproducibly detected markers of vCJD infectivity in tissue homogenates. The approach outlined has successfully compared in vitro diagnostics assays for their sensitivity and reproducibility and is a first step toward the evaluation of an assay suitable for blood donor screening/diagnosis of vCJD. © 2011 The Author(s). Vox Sanguinis © 2011 International Society of Blood Transfusion.

Methods for Measuring Lung Volumes: Is There a Better One?

PubMed

Tantucci, Claudio; Bottone, Damiano; Borghesi, Andrea; Guerini, Michele; Quadri, Federico; Pini, Laura

2016-01-01

Accurate measurement of lung volumes is of paramount importance to establish the presence of ventilatory defects and give insights for diagnostic and/or therapeutic purposes. It was the aim of this study to measure lung volumes in subjects with respiratory disorders and in normal controls by 3 different techniques (plethysmographic, dilutional and radiographic methods), in an attempt to clarify the role of each of them in performing such a task, without any presumptive 'a priori' superiority of one method above others. Patients andMethods: In different groups of subjects with obstructive and restrictive ventilatory defects and in a normal control group, total lung capacity, functional residual capacity (FRC) and residual volume were measured by body plethysmography, multi-breath helium (He) dilution and radiographic CT scan method with spirometric gating. The 3 methods gave comparable results in normal subjects and in patients with a restrictive defect. In patients with an obstructive defect, CT scan and plethysmography showed similar lung volumes, while on average significantly lower lung volumes were obtained with the He dilution technique. Taking into account that the He dilution technique does primarily measure FRC during tidal breathing, our data suggest that in some patients with an obstructive defect, a number of small airways can be functionally closed at end-expiratory lung volume, preventing He to reach the lung regions subserved by these airways. In all circumstances, both CT scan with spirometric gating and plethysmographic methods provide similar values of lung volumes. In contrast, the He dilution method can measure lower lung volumes in some patients with chronic airflow obstruction. © 2016 S. Karger AG, Basel.

Olfactory Impact of Higher Alcohols on Red Wine Fruity Ester Aroma Expression in Model Solution.

PubMed

Cameleyre, Margaux; Lytra, Georgia; Tempere, Sophie; Barbe, Jean-Christophe

2015-11-11

This study focused on the impact of five higher alcohols on the perception of fruity aroma in red wines. Various aromatic reconstitutions were prepared, consisting of 13 ethyl esters and acetates and 5 higher alcohols, all at the average concentrations found in red wine. These aromatic reconstitutions were prepared in several matrices. Sensory analysis revealed the interesting behavior of certain compounds among the five higher alcohols following their individual addition or omission. The "olfactory threshold" of the fruity pool was evaluated in several matrices: dilute alcohol solution, dilute alcohol solution containing 3-methylbutan-1-ol or butan-1-ol individually, and dilute alcohol solution containing the mixture of five higher alcohols, blended together at various concentrations. The presence of 3-methylbutan-1-ol or butan-1-ol alone led to a significant decrease in the "olfactory threshold" of the fruity reconstitution, whereas the mixture of alcohols raised the olfactory threshold. Sensory profiles highlighted changes in the perception of fruity nuances in the presence of the mixture of higher alcohols, with specific perceptive interactions, including a relevant masking effect on fresh- and jammy-fruit notes of the fruity mixture in both dilute alcohol solution and dearomatized red wine matrices. When either 3-methylbutan-1-ol or butan-1-ol was added to the fruity reconstitution in dilute alcohol solution, an enhancement of butyric notes was reported with 3-methylbutan-1-ol and fresh- and jammy-fruit with butan-1-ol. This study, the first to focus on the impact of higher alcohols on fruity aromatic expression, revealed that these compounds participate, both quantitatively and qualitatively, in masking fruity aroma perception in a model fruity wine mixture.

A general framework for the regression analysis of pooled biomarker assessments.

PubMed

Liu, Yan; McMahan, Christopher; Gallagher, Colin

2017-07-10

As a cost-efficient data collection mechanism, the process of assaying pooled biospecimens is becoming increasingly common in epidemiological research; for example, pooling has been proposed for the purpose of evaluating the diagnostic efficacy of biological markers (biomarkers). To this end, several authors have proposed techniques that allow for the analysis of continuous pooled biomarker assessments. Regretfully, most of these techniques proceed under restrictive assumptions, are unable to account for the effects of measurement error, and fail to control for confounding variables. These limitations are understandably attributable to the complex structure that is inherent to measurements taken on pooled specimens. Consequently, in order to provide practitioners with the tools necessary to accurately and efficiently analyze pooled biomarker assessments, herein, a general Monte Carlo maximum likelihood-based procedure is presented. The proposed approach allows for the regression analysis of pooled data under practically all parametric models and can be used to directly account for the effects of measurement error. Through simulation, it is shown that the proposed approach can accurately and efficiently estimate all unknown parameters and is more computational efficient than existing techniques. This new methodology is further illustrated using monocyte chemotactic protein-1 data collected by the Collaborative Perinatal Project in an effort to assess the relationship between this chemokine and the risk of miscarriage. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Wheat and ultra high diluted gibberellic acid--further experiments and re-analysis of data.

PubMed

Endler, Peter Christian; Scherer-Pongratz, Waltraud; Lothaller, Harald; Stephen, Saundra

2015-10-01

Following studies (a) on wheat seedlings and ultra high diluted silver nitrate, and (b) on amphibians and an ultra high diluted hormone, (c) a bio-assay on wheat and extremely diluted gibberellic acid was standardized. This assay was intended to combine the easy-to-handle aspect of (a) and biologically interesting aspects of (b). The purpose of the data analysis presented here was to investigate the influence of an extreme dilution of gibberellic acid on wheat stalk length and to determine the influence of external factors on the experimental outcome. Grains of winter wheat (Triticum aestivum, Capo variety) were observed under the influence of extremely diluted gibberellic acid (10(-30)) prepared by stepwise dilution and agitation according to a protocol derived from homeopathy ('G30x'). Analogously prepared water was used for control ('W30x'). 16 experiments including 8000+8000 grains were performed by 9 researchers. Experiments that were performed between January and April showed inconsistent results, whereas most of the experiments performed between September and December showed shorter stalks in the G30x group. This was confirmed by correlation analysis (p<0.01). Thus winter/spring experiments and autumn experiments were analysed separately. When all 10 autumn experiments were pooled, mean stalk lengths (mm) were 48.3±21.4 for the verum group and 52.1±20.4 for control (mean±SD) at grain level (N=5000 per group) and ±5.3 and ±5.1 respectively at dish level. In other words, verum stalk length (92.67%) was 7.33% smaller than control stalk length (100%). The effect size is small when calculation is done on the basis of grains (d=0.18) but, due to the smaller SD at dish level, medium when done on the basis of dishes (d=0.73). The inhibiting effect was observed by 6 of the 6 researchers who performed the autumn experiments. The model may be useful for further research as there exists a theoretical justification due to previous studies with wheat and extremely diluted silver nitrate, as well as to previous studies with amphibians and diluted hormones, and its methods are well standardized. Data confirm the hypothesis that information can be stored in the test liquid, even at a dilution of the original substance beyond Avogadro's value; and that the wheat bio-assay is sensitive to such information. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Compositional analysis of dilute nitride doped indium antimonide bulk crystal by VDS technique

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

Deshpande, Manisha, E-mail: manishauj@gmail.com; Department of Physics, Mithibai College, Vile Parle; Maske, Dilip

2016-05-06

Dilute nitrides are suitable materials for fabrication of devices in detection of long wavelength infrared region. Dilute nitride doped Indium antimonide bulk crystals were grown using vertical directional solidification technique. The compositional characteristics of the crystals were carried out using EDS. The analysis was simulated and compared with observations using DTSA II software for accuracy. The ingots have uniform composition of Indium and Antimony. The actual nitrogen composition measured using EDS was 0.136% for doped nitrogen composition 0.1% except near conical end where it was 0.1%. The study of bonding between nitrogen, Indium and antimony was carried out using SIMS.more » The analysis shows strong presence of In-N bonding along with In-Sb bonds which indicates nitrogen has replaced antimony atoms in crystal lattice.« less

Single-molecule dilution and multiple displacement amplification for molecular haplotyping.

PubMed

Paul, Philip; Apgar, Josh

2005-04-01

Separate haploid analysis is frequently required for heterozygous genotyping to resolve phase ambiguity or confirm allelic sequence. We demonstrate a technique of single-molecule dilution followed by multiple strand displacement amplification to haplotype polymorphic alleles. Dilution of DNA to haploid equivalency, or a single molecule, is a simple method for separating di-allelic DNA. Strand displacement amplification is a robust method for non-specific DNA expansion that employs random hexamers and phage polymerase Phi29 for double-stranded DNA displacement and primer extension, resulting in high processivity and exceptional product length. Single-molecule dilution was followed by strand displacement amplification to expand separated alleles to microgram quantities of DNA for more efficient haplotype analysis of heterozygous genes.

Evaluation of the VERSANT HCV RNA 3.0 assay for quantification of hepatitis C virus RNA in serum.

PubMed

Trimoulet, Pascale; Halfon, Philippe; Pohier, Eric; Khiri, Hacène; Chêne, Geneviève; Fleury, Hervé

2002-06-01

We assessed the performance of a new assay (VERSANT HCV RNA 3.0 [bDNA 3.0] assay [Bayer Diagnostics]) to quantitate HCV RNA levels and compared the results of the bDNA 3.0 assay to results of the Quantiplex HCV RNA 2.0 (bDNA 2.0) assay. Samples used in this study included 211 serum specimens from hepatitis C virus (HCV)-infected persons from two sites (Bordeaux and Marseille, France) with different genotypes; 383 serum specimens from HCV antibody-negative, HCV RNA-negative persons; and serial dilutions of World Health Organization (WHO) HCV RNA standard at a titer of 100,000 IU/ml. The specificity of the bDNA 3.0 assay was 98.2%. A high correlation was observed between expected and observed values in all dilutions of WHO standard (r = 0.9982), in serial dilutions of pooled samples (r = 0.9996), and in diluted sera from different HCV genotypes (r = 0.9930 to 0.9995). The standard deviations (SD) for the within-run and between-run reproducibility of the bDNA 3.0 assay were

Evaluation of the VERSANT HCV RNA 3.0 Assay for Quantification of Hepatitis C Virus RNA in Serum

PubMed Central

Trimoulet, Pascale; Halfon, Philippe; Pohier, Eric; Khiri, Hacène; Chêne, Geneviève; Fleury, Hervé

2002-01-01

We assessed the performance of a new assay (VERSANT HCV RNA 3.0 [bDNA 3.0] assay [Bayer Diagnostics]) to quantitate HCV RNA levels and compared the results of the bDNA 3.0 assay to results of the Quantiplex HCV RNA 2.0 (bDNA 2.0) assay. Samples used in this study included 211 serum specimens from hepatitis C virus (HCV)-infected persons from two sites (Bordeaux and Marseille, France) with different genotypes; 383 serum specimens from HCV antibody-negative, HCV RNA-negative persons; and serial dilutions of World Health Organization (WHO) HCV RNA standard at a titer of 100,000 IU/ml. The specificity of the bDNA 3.0 assay was 98.2%. A high correlation was observed between expected and observed values in all dilutions of WHO standard (r = 0.9982), in serial dilutions of pooled samples (r = 0.9996), and in diluted sera from different HCV genotypes (r = 0.9930 to 0.9995). The standard deviations (SD) for the within-run and between-run reproducibility of the bDNA 3.0 assay were ≤0.2 and ≤0.14, respectively. The intersite SD ranged from 0.03 to 0.14. The bDNA 3.0 assay results were positively correlated with the bDNA 2.0 assay results (r = 0.9533). Taking in account the overall performance, this assay could be used as a routine tool for the HCV RNA quantification. PMID:12037059

Quantifying T Lymphocyte Turnover

PubMed Central

De Boer, Rob J.; Perelson, Alan S.

2013-01-01

Peripheral T cell populations are maintained by production of naive T cells in the thymus, clonal expansion of activated cells, cellular self-renewal (or homeostatic proliferation), and density dependent cell life spans. A variety of experimental techniques have been employed to quantify the relative contributions of these processes. In modern studies lymphocytes are typically labeled with 5-bromo-2′-deoxyuridine (BrdU), deuterium, or the fluorescent dye carboxy-fluorescein diacetate succinimidyl ester (CFSE), their division history has been studied by monitoring telomere shortening and the dilution of T cell receptor excision circles (TRECs) or the dye CFSE, and clonal expansion has been documented by recording changes in the population densities of antigen specific cells. Proper interpretation of such data in terms of the underlying rates of T cell production, division, and death has proven to be notoriously difficult and involves mathematical modeling. We review the various models that have been developed for each of these techniques, discuss which models seem most appropriate for what type of data, reveal open problems that require better models, and pinpoint how the assumptions underlying a mathematical model may influence the interpretation of data. Elaborating various successful cases where modeling has delivered new insights in T cell population dynamics, this review provides quantitative estimates of several processes involved in the maintenance of naive and memory, CD4+ and CD8+ T cell pools in mice and men. PMID:23313150

Isotope dilution ICP-MS with laser-assisted sample introduction for direct determination of sulfur in petroleum products.

PubMed

Boulyga, Sergei F; Heilmann, Jens; Heumann, Klaus G

2005-08-01

Inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with direct laser-assisted introduction of isotope-diluted samples into the plasma, using a laser ablation system with high ablation rates, was developed for accurate sulfur determinations in different petroleum products such as 'sulfur-free' premium gasoline, diesel fuel, and heating oil. Two certified gas oil reference materials were analyzed for method validation. Two different 34S-enriched spike compounds, namely, elementary sulfur dissolved in xylene and dibenzothiophene in hexane, were synthesized and tested for their usefulness in this isotope dilution technique. The isotope-diluted sample was adsorbed on a filter-paper-like material, which was fixed in a special holder for irradiation by the laser beam. Under these conditions no time-dependent spike/analyte fractionation was only observed for the dibenzothiophene spike during the laser ablation process, which means that the measured 34S/32S isotope ratio of the isotope-diluted sample remained constant-a necessary precondition for accurate results with the isotope dilution technique. A comparison of LA-ICP-IDMS results with the certified values of the gas oil reference materials and with results obtained from ICP-IDMS analyses with wet sample digestion demonstrated the accuracy of the new LA-ICP-IDMS method in the concentration range of 9.2 microg g(-1) ('sulfur-free' premium gasoline) to 10.4 mg g(-1) (gas oil reference material BCR 107). The detection limit for sulfur by LA-ICP-IDMS is 0.04 microg g(-1) and the analysis time is only about 10 min, which therefore also qualifies this method for accurate determinations of low sulfur contents in petroleum products on a routine level.

Quantum dot-based western blot for sensitive detection of pig serum antibody to actinobacillus pleuropneumoniae

NASA Astrophysics Data System (ADS)

Cişmileanu, Ana; Sima, Cornelia; Grigoriu, Constantin

2007-08-01

A quantum dot - immunoglobulin conjugate specific for pig IgG, was obtained by carbodiimide chemistry. We used a Western blot technique for detecting specific antibodies against Actinobacillus pleuropneumoniae (A. pp), which cause porcine pleuropneumonia. The antigen used in this technique was Apx haemolysin which is an important virulence factor of A. pp and it induces protective immunity in vaccined pigs. The detection on Western blot membrane was possible at 1/50 dilution of quantum dot conjugate at a dilution of pig serum till 1/6400. The results for pig serum demonstrated a higher sensitivity of QD-based Western blot technique for the presence of antibodies specific for Apx haemolysin in comparison with similar classical techniques (with coloured substrate for enzyme present in secondary antibody conjugate).

Optimization of single plate-serial dilution spotting (SP-SDS) with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples.

PubMed

Thomas, Pious; Sekhar, Aparna C; Upreti, Reshmi; Mujawar, Mohammad M; Pasha, Sadiq S

2015-12-01

We propose a simple technique for bacterial and yeast cfu estimations from diverse samples with no prior idea of viable counts, designated as single plate-serial dilution spotting (SP-SDS) with the prime recommendation of sample anchoring (10 0 stocks). For pure cultures, serial dilutions were prepared from 0.1 OD (10 0 ) stock and 20 μl aliquots of six dilutions (10 1 -10 6 ) were applied as 10-15 micro-drops in six sectors over agar-gelled medium in 9-cm plates. For liquid samples 10 0 -10 5 dilutions, and for colloidal suspensions and solid samples (10% w/v), 10 1 -10 6 dilutions were used. Following incubation, at least one dilution level yielded 6-60 cfu per sector comparable to the standard method involving 100 μl samples. Tested on diverse bacteria, composite samples and Saccharomyces cerevisiae , SP-SDS offered wider applicability over alternative methods like drop-plating and track-dilution for cfu estimation, single colony isolation and culture purity testing, particularly suiting low resource settings.

Simple optical method of qualitative assessment of sperm motility: preliminary results

NASA Astrophysics Data System (ADS)

Sozanska, Agnieszka; Kolwas, Krystyna; Galas, Jacek; Blocki, Narcyz; Czyzewski, Adam

2005-09-01

The examination of quality of the sperm ejaculate is one of the most important steps in artificial fertilization procedure. The main aim of semen storage centres is to characterise the best semen quality for fertilization. Reliable information about sperm motility is also one the most important parameters for in vitro laboratory procedures. There exist very expensive automated methods for semen analysis but they are unachievable for most of laboratories and semen storage centres. Motivation for this study is to elaborate a simple, cheap, objective and repeatable method for semen motility assessment. The method enables to detect even small changes in motility introduced by medical, physical or chemical factors. To test the reliability of the method we used cryopreserved bull semen from Lowicz Semen Storage Centre. The examined sperm specimen was warmed in water bath and then centrifuged. The best semen was collected by the swim-up technique and diluted to a proper concentration. Several semen concentrations and dilutions were tested in order to find the best probe parameters giving repeatable results. For semen visualization we used the phase-contrast microscope with a CCD camera. A PC computer was used to acquire and to analyse the data. The microscope table equipped with a microscope glass pool 0.7mm deep instead of some conventional plane microscope slides was stabilised at the temperature of 37°C. The main idea of our method is based on a numerical processing of the optical contrast of the sperm images which illustrates the dynamics of the sperm cells movement and on appropriate analysis of a grey scale level of the superimposed images. An elaborated numerical algorithm allows us to find the relative amount of motile sperm cells. The proposed method of sperm motility assessment seems to be objective and repeatable.

Use of Empty Fruit Bunches from the oil palm for bioethanol production: a thorough comparison between dilute acid and dilute alkali pretreatment.

PubMed

Chiesa, S; Gnansounou, E

2014-05-01

In the present work, two pretreatment techniques using either dilute acid (H2SO4) or dilute alkali (NaOH) have been compared for producing bioethanol from Empty Fruit Bunches (EFBs) from oil palm tree, a relevant feedstock for tropical countries. Treatments' performances under different conditions have been assessed and statistically optimized with respect to the response upon standardized enzymatic saccharification. The dilute acid treatment performed at optimal conditions (161.5°C, 9.44 min and 1.51% acid loading) gave 85.5% glucose yield, comparable to those of other commonly investigated feedstocks. Besides, the possibility of using fibers instead of finely ground biomass may be of economic interest. Oppositely, treatment with dilute alkali has shown lower performances under the conditions explored, most likely given the relatively significant lignin content, suggesting that the use of stronger alkali regime (with the associated drawbacks) is unavoidable to improve the performance of this treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of very low doses of mediators on fungal laccase activity - nonlinearity beyond imagination

PubMed Central

Malarczyk, Elzbieta; Kochmanska-Rdest, Janina; Jarosz-Wilkolazka, Anna

2009-01-01

Laccase, an enzyme responsible for aerobic transformations of natural phenolics, in industrial applications requires the presence of low-molecular substances known as mediators, which accelerate oxidation processes. However, the use of mediators is limited by their toxicity and the high costs of exploitation. The activation of extracellular laccase in growing fungal culture with highly diluted mediators, ABTS and HBT is described. Two high laccase-producing fungal strains, Trametes versicolor and Cerrena unicolor, were used in this study as a source of enzyme. Selected dilutions of the mediators significantly increased the activity of extracellular laccase during 14 days of cultivation what was distinctly visible in PAGE technique and in colorimetric tests. The same mediator dilutions increased demethylation properties of laccase, which was demonstrated during incubation of enzyme with veratric acid. It was established that the activation effect was assigned to specific dilutions of mediators. Our dose-response dilution process smoothly passes into the range of action of homeopathic dilutions and is of interest for homeopaths. PMID:19732425

Procedures for increasing the use of car pools for work trips.

DOT National Transportation Integrated Search

1979-01-01

This report describes methods and techniques that could be used to increase the use of car pools in Virginia. Two approaches are described. The first employs those methods that serve as an incentive for persons to form car pools, such as preferential...

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

Smith, C H

The chemistry of the various types of reactions possible between a carboxyl-terminated butadiene/acrylonitrile (CBTN) liquid copolymer and a diglycidyl ether of bisphenol A (DGEBA) type epoxy resin to prepare a CTBN/DGEBA adduct is discussed. Both a dilution and a non-dilution synthesis techniqu are described. Several properties of the CTBN precursor and the modified epoxy resin were determined and are presented.

Stable isotope dilution analysis of hydrologic samples by inductively coupled plasma mass spectrometry

USGS Publications Warehouse

Garbarino, John R.; Taylor, Howard E.

1987-01-01

Inductively coupled plasma mass spectrometry is employed in the determination of Ni, Cu, Sr, Cd, Ba, Ti, and Pb in nonsaline, natural water samples by stable isotope dilution analysis. Hydrologic samples were directly analyzed without any unusual pretreatment. Interference effects related to overlapping isobars, formation of metal oxide and multiply charged ions, and matrix composition were identified and suitable methods of correction evaluated. A comparability study snowed that single-element isotope dilution analysis was only marginally better than sequential multielement isotope dilution analysis. Accuracy and precision of the single-element method were determined on the basis of results obtained for standard reference materials. The instrumental technique was shown to be ideally suited for programs associated with certification of standard reference materials.

Automated measurement of respiratory gas exchange by an inert gas dilution technique

NASA Technical Reports Server (NTRS)

Sawin, C. F.; Rummel, J. A.; Michel, E. L.

1974-01-01

A respiratory gas analyzer (RGA) has been developed wherein a mass spectrometer is the sole transducer required for measurement of respiratory gas exchange. The mass spectrometer maintains all signals in absolute phase relationships, precluding the need to synchronize flow and gas composition as required in other systems. The RGA system was evaluated by comparison with the Douglas bag technique. The RGA system established the feasibility of the inert gas dilution method for measuring breath-by-breath respiratory gas exchange. This breath-by-breath analytical capability permits detailed study of transient respiratory responses to exercise.

Target analyte quantification by isotope dilution LC-MS/MS directly referring to internal standard concentrations--validation for serum cortisol measurement.

PubMed

Maier, Barbara; Vogeser, Michael

2013-04-01

Isotope dilution LC-MS/MS methods used in the clinical laboratory typically involve multi-point external calibration in each analytical series. Our aim was to test the hypothesis that determination of target analyte concentrations directly derived from the relation of the target analyte peak area to the peak area of a corresponding stable isotope labelled internal standard compound [direct isotope dilution analysis (DIDA)] may be not inferior to conventional external calibration with respect to accuracy and reproducibility. Quality control samples and human serum pools were analysed in a comparative validation protocol for cortisol as an exemplary analyte by LC-MS/MS. Accuracy and reproducibility were compared between quantification either involving a six-point external calibration function, or a result calculation merely based on peak area ratios of unlabelled and labelled analyte. Both quantification approaches resulted in similar accuracy and reproducibility. For specified analytes, reliable analyte quantification directly derived from the ratio of peak areas of labelled and unlabelled analyte without the need for a time consuming multi-point calibration series is possible. This DIDA approach is of considerable practical importance for the application of LC-MS/MS in the clinical laboratory where short turnaround times often have high priority.

Effect of various concentrations of butylated hydroxyanisole and butylated hydroxytoluene on freezing capacity of Turkman stallion sperm.

PubMed

Seifi-Jamadi, Afshin; Kohram, Hamid; Zareh-Shahne, Ahmad; Dehghanizadeh, Parvaneh; Ahmad, Ejaz

2016-07-01

The present study aimed to determine the effect of different concentrations of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on post-thaw stallion sperm quality. The ejaculates collected from four healthy mature Turkmen stallions were pooled and divided into eight aliquots. The samples were diluted with extenders containing different concentrations (0.5, 1 or 2mM/mL) of BHA or BHT. The positive control (PC) samples were diluted with extender containing 0.5% ethanol (v/v) whereas; the negative control (NC) samples were diluted with basic extender only. Semen samples were frozen according to a standard protocol. After thawing of samples, sperm motility, viability, membrane integrity, total abnormality and lipid peroxidation were assessed. The greatest (P<0.05) values for total sperm motility, viability and plasma membrane functionality and least values for malonedialdehyde (MDA) concentration were observed in samples supplemented either with 1mM BHT or 2mM BHA. However, the progressive motility was greater (P<0.05) only in samples treated with 2mM BHA. In conclusion, the use of 1mM BHT or 2mM BHA in extender improves the freezing capacity of stallion sperm by reducing oxidative stress during freeze-thaw process. Copyright © 2016 Elsevier B.V. All rights reserved.

Levels of cyclic-2,3-diphosphoglycerate in Methanobacterium thermoautotrophicum during phosphate limitation.

PubMed Central

Seely, R J; Fahrney, D E

1984-01-01

Batch-grown Methanobacterium thermoautotrophicum cells grew nonexponentially in the absence of exogenous Pi until intracellular cyclic-2,3-diphosphoglycerate (cyclic DPG) had fallen below 2 mumol/g (dry weight), the limit of detection. Growth resumed immediately upon transfer to medium containing Pi Cyclic DPG levels were also below detection in Pi-limited chemostat cultures operating at a dilution rate of 0.173 h-1 (4-h doubling time), with reservoir Pi concentrations below 200 microM. At this dilution rate, the Pi concentration in the culture was 4 microM. An H2-limited steady state was achieved with 400 microM Pi in the inflowing medium (67 microM in the culture). The cyclic DPG content of these cells was 72 to 74 mumol/g, about one-third the amount in batch-grown cells. The specific growth rate accelerated immediately to 0.36 h-1 (1.9-h doubling time) under washout conditions at high dilution rate. The cellular content of cyclic DPG declined over a 2-h period, and then increased rapidly as the Pi level in the medium approached 200 microM. Expansion of the cyclic DPG pool coincided with a marked increase in Pi assimilation. These results indicated that M. thermoautotrophicum accumulated cyclic DPG only when Pi and H2 were readily available. PMID:6480564

Levels of cyclic-2,3-diphosphoglycerate in Methanobacterium thermoautotrophicum during phosphate limitation.

PubMed

Seely, R J; Fahrney, D E

1984-10-01

Batch-grown Methanobacterium thermoautotrophicum cells grew nonexponentially in the absence of exogenous Pi until intracellular cyclic-2,3-diphosphoglycerate (cyclic DPG) had fallen below 2 mumol/g (dry weight), the limit of detection. Growth resumed immediately upon transfer to medium containing Pi Cyclic DPG levels were also below detection in Pi-limited chemostat cultures operating at a dilution rate of 0.173 h-1 (4-h doubling time), with reservoir Pi concentrations below 200 microM. At this dilution rate, the Pi concentration in the culture was 4 microM. An H2-limited steady state was achieved with 400 microM Pi in the inflowing medium (67 microM in the culture). The cyclic DPG content of these cells was 72 to 74 mumol/g, about one-third the amount in batch-grown cells. The specific growth rate accelerated immediately to 0.36 h-1 (1.9-h doubling time) under washout conditions at high dilution rate. The cellular content of cyclic DPG declined over a 2-h period, and then increased rapidly as the Pi level in the medium approached 200 microM. Expansion of the cyclic DPG pool coincided with a marked increase in Pi assimilation. These results indicated that M. thermoautotrophicum accumulated cyclic DPG only when Pi and H2 were readily available.

48 CFR 9904.418-50 - Techniques for application.

Code of Federal Regulations, 2010 CFR

2010-10-01

... objective's allocation base data shall be excluded from the base used to allocate the pool. (g) Use of... which the pool relates. (c) Change in allocation base. No change in an existing indirect cost pool allocation base is required if the allocation resulting from the existing base does not differ materially...

Detection of Pathogenic Protozoa in the Diagnostic Laboratory: Result Reproducibility, Specimen Pooling, and Competency Assessment▿

PubMed Central

Libman, M. D.; Gyorkos, T. W.; Kokoskin, E.; MacLean, J. D.

2008-01-01

Stool microscopy as performed in clinical parasitology laboratories is a complex procedure with subjective interpretation. Quality assurance (QA) programs often emphasize proficiency testing as an assessment tool. We describe a result reproducibility assessment tool, which can form part of a broader QA program, and which is based on the blinded resubmission of selected clinical samples, using concordance between the reports of the initial and resubmitted specimen as an indicator. Specimens preserved in sodium acetate-acetic acid-formalin can be stored for several months for use in such a program. The presence of multiple protozoa in one specimen does not affect concordance. Some dilution of specimens occurs in this process, and this may explain poor concordance when specimens with low protozoal concentrations are resubmitted. Evaluation of this tool in a large parasitology laboratory revealed concordance rates for pathogenic protozoa (Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Dientamoeba fragilis) of about 80%, which may be considered for use as a benchmark value. We also used this tool to demonstrate that when pairs of specimens from one patient are pooled to create a single specimen, concordance between the results of the individual and pooled specimens is high. PMID:18448690

Kinetic analysis of lead metabolism in healthy humans

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

Rabinowitz, M.B.; Wetherill, G.W.; Kopple, J.D.

The steady state kinetics of lead metabolism were studied in five healthy men with stable isotope tracers. Subjects lived in a metabolic unit and ate constant low lead diets. Their intake was supplemented each day with 79 to 204 ..mu..g of enriched lead-204 as nitrate which was ingested with meals for 1 to 124 days. The concentration and isotopic composition of lead was determined serially in blood, urine, feces, and diet and less commonly in hair, nails, sweat, bone, and alimentary tract secretions by isotopic dilution, mass spectrometric analysis. The data suggest a three-compartmental model for lead metabolism. The firstmore » compartment encompasses blood and is 1.5 to 2.2 times larger than the blood mass. It contains approximately 1.7 to 2.0 mg of lead and has a mean life of 35 days. This pool is in direct communication with ingested lead, urinary lead, and pools two and three. The second compartment is largely composed of soft tissue, contains about 0.3 to 0.9 mg of lead, and has a mean life of approximately 40 days. This pool gives rise to lead in hair, nails, sweat, and salivary, gastric, pancreatic, and biliary secretions. Pool three resides primarily in the skeleton, contains the vast quantity of body lead, and has a very slow mean life. Bones appear to differ in their rates of lead turnover. Within the relatively small changes in blood lead observed in the present study, the transfer coefficients between the pools remained constant.« less

Wet chemical techniques for passivation of YBa2Cu3O7(7-x)

NASA Technical Reports Server (NTRS)

Vasquez, R. P.; Foote, M. C.; Hunt, B. D.

1989-01-01

Wet chemical techniques are described for treatment of YBa2Cu3O(7-x) surfaces, resulting in the formation of native compounds with little or no reactivity to water. Promising native compounds include CuI, BaSO4, CuS, Cu2S, and the oxalates, all of which are either insoluble or have very low solubility in water. Treatment with dilute HI results in the formation of a native iodide film which is 80-90 percent CuI with small amounts of YI3 and BaI2. Treatment with dilute H2SO4 results in the formation of a film which is 95 percent BaSO4 and 5 percent Y2(SO4)3. Cu2S is formed on the surface with a dilute Na2S solution. An oxalate film with equal amounts of Y2(C2O4)3 and BaC2O4 results from treatment with dilute oxalic acid. X-ray photoelectron spectra show no significant changes when the sulfide, sulfate, or oxalate films are dipped in water, while the iodide film shows evidence of Cu(OH)2 formation.

Polymer relaxation and stretching dynamics in semi-dilute DNA solutions: a single molecule study

NASA Astrophysics Data System (ADS)

Hsiao, Kai-Wen; Brockman, Christopher; Schroeder, Charles

2015-03-01

In this work, we study polymer relaxation and stretching dynamics in semi-dilute DNA solutions using single molecule techniques. Using this approach, we uncover a unique scaling relation for longest polymer relaxation time that falls in the crossover regime described by semi-flexible polymer solutions, which is distinct from truly flexible polymer chains. In addition, we performed a series of step-strain experiments on single polymers in semi-dilute solutions in planar extensional flow using an automated microfluidic trap. In this way, we are able to precisely control the flow strength and the amount of strain applied to single polymer chains, thereby enabling direct observation of the full stretching and relaxation process in semi-dilute solutions during transient start-up and flow cessation. Interestingly, we observe polymer individualism in the conformation of single chains in semi-dilute solutions, which to our knowledge has not yet been observed. In addition, we observe the relaxation data can be explained by a multi-exponential decay process after flow cessation in semi-dilute solutions. Overall, our work reports key advance in non-dilute polymer systems from a molecular perspective via direct observation of dynamics in strong flows. DOW fellowship.

Automatic dilution gaging of rapidly varying flow

USGS Publications Warehouse

Duerk, M.D.

1983-01-01

The analysis showed that the discharges measured by dye-dilution techniques were generally within ± 10 percent of the discharges determined from ratings established by current-meter measurements. Larger differences were noted at the start of and on the rising limb of four hydrographs. Of the 20 storms monitored, dilution measurements on 17 were of acceptable accuracy. Peak discharges from the open-channel site ranged from 0 to 12 percent departures from the existing rating whereas the comparison of peak discharge at the storm sewer site ranged from 0 to 5 percent departures from the existing rating.

Single polymer dynamics in semi-dilute unentangled and entangled solutions: from molecular conformation to normal stress

NASA Astrophysics Data System (ADS)

Schroeder, Charles

Semi-dilute polymer solutions are encountered in a wide array of applications such as advanced 3D printing technologies. Semi-dilute solutions are characterized by large fluctuations in concentration, such that hydrodynamic interactions, excluded volume interactions, and transient chain entanglements may be important, which greatly complicates analytical modeling and theoretical treatment. Despite recent progress, we still lack a complete molecular-level understanding of polymer dynamics in these systems. In this talk, I will discuss three recent projects in my group to study semi-dilute solutions that focus on single molecule studies of linear and ring polymers and a new method to measure normal stresses in microfluidic devices based on the Stokes trap. In the first effort, we use single polymer techniques to investigate the dynamics of semi-dilute unentangled and semi-dilute entangled DNA solutions in extensional flow, including polymer relaxation from high stretch, transient stretching dynamics in step-strain experiments, and steady-state stretching in flow. In the semi-dilute unentangled regime, our results show a power-law scaling of the longest polymer relaxation time that is consistent with scaling arguments based on the double cross-over regime. Upon increasing concentration, we observe a transition region in dynamics to the entangled regime. We also studied the transient and steady-state stretching dynamics in extensional flow using the Stokes trap, and our results show a decrease in transient polymer stretch and a milder coil-to-stretch transition for semi-dilute polymer solutions compared to dilute solutions, which is interpreted in the context of a critical Weissenberg number Wi at the coil-to-stretch transition. Interestingly, we observe a unique set of polymer conformations in semi-dilute unentangled solutions that are highly suggestive of transient topological entanglements in solutions that are nominally unentangled at equilibrium. Taken together, these results suggest that the transient stretching pathways in semi-dilute solution extensional flows are qualitatively different than for both dilute solutions and for semi-dilute solutions in shear flow. In a second effort, we studied the dynamics of ring polymers in background solutions of semi-dilute linear polymers. Interestingly, we observe strikingly large fluctuations in steady-state polymer extension for ring polymers in flow, which occurs due to the interplay between polymer topology and concentration leading to chain `threading' in flow. In a third effort, we developed a new microfluidic method to measure normal stress and extensional viscosity that can be loosely described as passive yet non-linear microrheology. In particular, we incorporated 3-D particle imaging velocimetry (PIV) with the Stokes trap to study extensional flow-induced particle migration in semi-dilute polymer solutions. Experimental results are analyzed using the framework of a second-order-fluid model, which allows for measurement of normal stress and extensional viscosity in semi-dilute polymer solutions, all of which is a first-of-its-kind demonstration. Microfluidic measurements of extensional viscosity are directly compared to the dripping-onto-substrate or DOS method, and good agreement is generally observed. Overall, our work aims to provide a molecular-level understanding of the role of polymer topology and concentration on bulk rheological properties by using single polymer techniques.

High molecular weight dissolved organic matter enrichment selects for methylotrophs in dilution to extinction cultures

PubMed Central

Sosa, Oscar A; Gifford, Scott M; Repeta, Daniel J; DeLong, Edward F

2015-01-01

The role of bacterioplankton in the cycling of marine dissolved organic matter (DOM) is central to the carbon and energy balance in the ocean, yet there are few model organisms available to investigate the genes, metabolic pathways, and biochemical mechanisms involved in the degradation of this globally important carbon pool. To obtain microbial isolates capable of degrading semi-labile DOM for growth, we conducted dilution to extinction cultivation experiments using seawater enriched with high molecular weight (HMW) DOM. In total, 93 isolates were obtained. Amendments using HMW DOM to increase the dissolved organic carbon concentration 4x (280 μM) or 10x (700 μM) the ocean surface water concentrations yielded positive growth in 4–6% of replicate dilutions, whereas <1% scored positive for growth in non-DOM-amended controls. The majority (71%) of isolates displayed a distinct increase in cell yields when grown in increasing concentrations of HMW DOM. Whole-genome sequencing was used to screen the culture collection for purity and to determine the phylogenetic identity of the isolates. Eleven percent of the isolates belonged to the gammaproteobacteria including Alteromonadales (the SAR92 clade) and Vibrio. Surprisingly, 85% of isolates belonged to the methylotrophic OM43 clade of betaproteobacteria, bacteria thought to metabolically specialize in degrading C1 compounds. Growth of these isolates on methanol confirmed their methylotrophic phenotype. Our results indicate that dilution to extinction cultivation enriched with natural sources of organic substrates has a potential to reveal the previously unsuspected relationships between naturally occurring organic nutrients and the microorganisms that consume them. PMID:25978545

Mathematical-Programming Approaches to Test Item Pool Design. Research Report.

ERIC Educational Resources Information Center

Veldkamp, Bernard P.; van der Linden, Wim J.; Ariel, Adelaide

This paper presents an approach to item pool design that has the potential to improve on the quality of current item pools in educational and psychological testing and thus to increase both measurement precision and validity. The approach consists of the application of mathematical programming techniques to calculate optimal blueprints for item…

48 CFR 9904.410-50 - Techniques for application.

Code of Federal Regulations, 2012 CFR

2012-10-01

... segment incurred by another segment shall be removed from the incurring segment's G&A expense pool. They... whole, shall be included in the receiving segment's G&A expense pool. (2) Any separate allocation of the... from the G&A expense pool required by 9904.410-40(a), and the particular final cost objective's cost...

48 CFR 9904.410-50 - Techniques for application.

Code of Federal Regulations, 2014 CFR

2014-10-01

... segment incurred by another segment shall be removed from the incurring segment's G&A expense pool. They... whole, shall be included in the receiving segment's G&A expense pool. (2) Any separate allocation of the... from the G&A expense pool required by 9904.410-40(a), and the particular final cost objective's cost...

48 CFR 9904.410-50 - Techniques for application.

Code of Federal Regulations, 2013 CFR

2013-10-01

... segment incurred by another segment shall be removed from the incurring segment's G&A expense pool. They... whole, shall be included in the receiving segment's G&A expense pool. (2) Any separate allocation of the... from the G&A expense pool required by 9904.410-40(a), and the particular final cost objective's cost...

Composite Sampling Approaches for Bacillus anthracis Surrogate Extracted from Soil

PubMed Central

France, Brian; Bell, William; Chang, Emily; Scholten, Trudy

2015-01-01

Any release of anthrax spores in the U.S. would require action to decontaminate the site and restore its use and operations as rapidly as possible. The remediation activity would require environmental sampling, both initially to determine the extent of contamination (hazard mapping) and post-decon to determine that the site is free of contamination (clearance sampling). Whether the spore contamination is within a building or outdoors, collecting and analyzing what could be thousands of samples can become the factor that limits the pace of restoring operations. To address this sampling and analysis bottleneck and decrease the time needed to recover from an anthrax contamination event, this study investigates the use of composite sampling. Pooling or compositing of samples is an established technique to reduce the number of analyses required, and its use for anthrax spore sampling has recently been investigated. However, use of composite sampling in an anthrax spore remediation event will require well-documented and accepted methods. In particular, previous composite sampling studies have focused on sampling from hard surfaces; data on soil sampling are required to extend the procedure to outdoor use. Further, we must consider whether combining liquid samples, thus increasing the volume, lowers the sensitivity of detection and produces false negatives. In this study, methods to composite bacterial spore samples from soil are demonstrated. B. subtilis spore suspensions were used as a surrogate for anthrax spores. Two soils (Arizona Test Dust and sterilized potting soil) were contaminated and spore recovery with composites was shown to match individual sample performance. Results show that dilution can be overcome by concentrating bacterial spores using standard filtration methods. This study shows that composite sampling can be a viable method of pooling samples to reduce the number of analysis that must be performed during anthrax spore remediation. PMID:26714315

The use of animal models in homeopathic research--a review of 2010-2014 PubMed indexed papers.

PubMed

Bonamin, Leoni Villano; Cardoso, Thayná Neves; de Carvalho, Aloísio Cunha; Amaral, Juliana Gimenez

2015-10-01

In the 1990s, a study was performed on the effects of highly diluted thyroxine on frog metamorphosis. This model represented one of the most discussed examples of the biological effects of high dilutions over the next two decades. In 2010, another critical conceptual review of the use of animal models in homeopathy and high-dilution research was published. The main contribution of these studies was the elucidation of the biological features and phenomenology of the effects of high dilutions on living systems, representing an important step forward in our understanding of the mechanisms of action of homeopathic medicines. We performed a further review of this line of investigation using the same methods. Fifty-three articles that were indexed in the PubMed database and used 12 different animal species were systematically evaluated. Only a fraction of the studies (29/53) reported herein were performed with "ultra high" dilutions. The other studies were performed with dilutions in ranges below 10(-23) (14/53 articles) or commercial complexes (10/53 articles). Only two articles reported negative results; both used in vivo protocols to test commercial complexes, one in fish and one in bees. The quality of the employed techniques improved in 2010-2014 compared with the studies that were reviewed previously in 2010, with the inclusion of more ethically refined protocols, including in vitro primary cell cultures and ex vivo studies (10/53 articles), often with three or more replicates and analyses of epigenetic mechanisms that were previously unknown in 2010. In our updated review of the past 5 years, we found further demonstrations of the biological effects of homeopathy using more refined animal models and in vitro techniques. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

[Comparison of single-indicator thermodilution versus gravimetric measurement in determination of extra-vascular lung water in dogs with acute respiratory distress syndrome].

PubMed

Shen, Ju-fang; Qiu, Hai-bo; Yang, Yi; Liu, Song-qiao; Chen, Yong-ming; Li, Jia-qiong; Wu, Bin; Ding, Hui-min

2006-06-01

To compare the measurement of extra-vascular lung water (EVLW) by a single-indicator dilution technique and measurement obtained by gravimetry in different types of acute respiratory distress syndrome (ARDS). Thirty-three dogs were randomly assigned to three groups: control group, oleic acid group and hydrochloric acid group. ARDS was reproduced by either intravenous injection of oleic acid or intratracheal instillation of hydrochloric acid. EVLW was measured before ARDS, at the onset of ARDS and 10 hours after ARDS by a single indicator dilution technique. Ten hours after ARDS, dogs were sacrificed and then EVLW was quantitated by a gravimetric measurement (golden standard). Hemodynamics and pulmonary gas exchange were determined. There was a close positive correlation (r=0.8820, P<0.05) between single indicator dilution and gravimetric measurements. However, the measurement with the single indicator dilution was consistently higher than the gravimetric measurement. In the control group, there was a positive correlation (r=0.9870, P<0.05) between the values of EVLW as measured by single indicator dilution and by gravimetric measurements. In the oleic acid group, there was also a significant correlation (r=0.9360, P<0.05) between the values of EVLW as measured by single indicator dilution and by gravimetric measurements. In the hydrochloric acid group, correlation (r=0.7950, P<0.05) was also found between EVLW as measured by the two methods. However, the correlation found was lower in the hydrochloric acid group than those in other two groups. Hydrochloric acid instillation resulted in a significant increase in shunting and the partial pressure of carbon dioxide in artery (PaCO(2)) compared with oleic acid group at 10 hours after ARDS. The results of measuring EVLW using single indicator dilution measurement are closely related with those of gravimetric measurement in ARDS, however, the correlations varies with the methods of reproduction of ARDS.

Isolation and structural characterization of sugarcane bagasse lignin after dilute phosphoric acid plus steam explosion pretreatment and its effect on cellulose hydrolysis

Treesearch

Jijiao Zeng; Zhaohui Tong; Letian Wang; J.Y. Zhu; Lonnie Ingram

2014-01-01

The structure of lignin after dilute phosphoric acid plus steam explosion pretreatment process of sugarcane bagasse in a pilot scale and the effect of the lignin extracted by ethanol on subsequent cellulose hydrolysis were investigated. The lignin structural changes caused by pretreatment were identified using advanced nondestructive techniques such as gel permeation...

A New Flow Control Technique Using Diluted Epinephrine in the N-butyl-2-cyanoacrylate Embolization of Visceral Artery Pseudoaneurysms Secondary to Chronic Pancreatitis

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

Morishita, Hiroyuki, E-mail: hmorif@koto.kpu-m.ac.jp; Yamagami, Takuji; Takeuchi, Yoshito

2012-08-15

Although n-butyl-2-cyanoacrylate (NBCA) has been used as an effective liquid embolization material, its indication for pseudoaneurysms has seemingly been limited because of the technical difficulties of using NBCA, such as reflux to the parent artery and causing significant infarction. Thus, considerable skill in using NBCA or a device to control blood flow during its polymerization is required to achieve embolization without severe complications. We report our new technique for controlling blood flow using diluted epinephrine in transcatheter arterial NBCA embolization of five pseudoaneurysms in four cases secondary to hemosuccus pancreaticus.

Simple and rapid detection of the porcine reproductive and respiratory syndrome virus from pig whole blood using filter paper.

PubMed

Inoue, Ryo; Tsukahara, Takamitsu; Sunaba, Chinatsu; Itoh, Mitsugi; Ushida, Kazunari

2007-04-01

The combination of Flinders Technology Associates filter papers (FTA cards) and real-time PCR was examined to establish a simple and rapid technique for the detection of porcine reproductive and respiratory syndrome virus (PRRSV) from whole pig blood. A modified live PRRS vaccine was diluted with either sterilised saline or pig whole blood, and the suspensions were applied onto the FTA cards. The real-time RT-PCR detection of PRRSV was performed directly with the samples applied to the FTA card without the RNA extraction step. Six whole blood samples from at random selected piglets in the PRRSV infected farm were also assayed in this study. The expected PCR product was successfully amplified from either saline diluted or pig whole blood diluted vaccine. The same PCR ampliocon was detected from all blood samples assayed in this study. This study suggested that the combination of an FTA card and real-time PCR is a rapid and easy technique for the detection of PRRSV. This technique can remarkably shorten the time required for PRRSV detection from whole blood and makes the procedure much easier.

Synovial Fluid Response to Extensional Flow: Effects of Dilution and Intermolecular Interactions

PubMed Central

Haward, Simon J.

2014-01-01

In this study, a microfluidic cross-slot device is used to examine the extensional flow response of diluted porcine synovial fluid (PSF) samples using flow-induced birefringence (FIB) measurements. The PSF sample is diluted to 10× 20× and 30× its original mass in a phosphate-buffered saline and its FIB response measured as a function of the strain rate at the stagnation point of the cross-slots. Equivalent experiments are also carried out using trypsin-treated PSF (t-PSF) in which the protein content is digested away using an enzyme. The results show that, at the synovial fluid concentrations tested, the protein content plays a negligible role in either the fluid's bulk shear or extensional flow behaviour. This helps support the validity of the analysis of synovial fluid HA content, either by microfluidic or by other techniques where the synovial fluid is first diluted, and suggests that the HA and protein content in synovial fluid must be higher than a certain minimum threshold concentration before HA-protein or protein-protein interactions become significant. However a systematic shift in the FIB response as the PSF and t-PSF samples are progressively diluted indicates that HA-HA interactions remain significant at the concentrations tested. These interactions influence FIB-derived macromolecular parameters such as the relaxation time and the molecular weight distribution and therefore must be minimized for the best validity of this method as an analytical technique, in which non-interaction between molecules is assumed. PMID:24651529

Synovial fluid response to extensional flow: effects of dilution and intermolecular interactions.

PubMed

Haward, Simon J

2014-01-01

In this study, a microfluidic cross-slot device is used to examine the extensional flow response of diluted porcine synovial fluid (PSF) samples using flow-induced birefringence (FIB) measurements. The PSF sample is diluted to 10× 20× and 30× its original mass in a phosphate-buffered saline and its FIB response measured as a function of the strain rate at the stagnation point of the cross-slots. Equivalent experiments are also carried out using trypsin-treated PSF (t-PSF) in which the protein content is digested away using an enzyme. The results show that, at the synovial fluid concentrations tested, the protein content plays a negligible role in either the fluid's bulk shear or extensional flow behaviour. This helps support the validity of the analysis of synovial fluid HA content, either by microfluidic or by other techniques where the synovial fluid is first diluted, and suggests that the HA and protein content in synovial fluid must be higher than a certain minimum threshold concentration before HA-protein or protein-protein interactions become significant. However a systematic shift in the FIB response as the PSF and t-PSF samples are progressively diluted indicates that HA-HA interactions remain significant at the concentrations tested. These interactions influence FIB-derived macromolecular parameters such as the relaxation time and the molecular weight distribution and therefore must be minimized for the best validity of this method as an analytical technique, in which non-interaction between molecules is assumed.

Use of vitamin B12 in joint lavage for determination of dilution factors of canine synovial fluid.

PubMed

de Bruin, Tanya; de Rooster, Hilde; van Bree, Henri; Cox, Eric

2005-11-01

To test a modified saline (0.9% NaCl) solution joint washing (lavage) technique that includes the use of vitamin B12 as an internal marker for the evaluation of synovial fluid dilution in lavage samples from canine joints. 9 plasma samples obtained from blood samples of 9 healthy dogs and 9 synovial fluid samples aspirated from stifle joints of 9 cadaveric dogs. Photometric absorbances of 25% vitamin B12 solution, canine synovial fluid, and canine plasma were measured in a spectrophotometer to establish an optimal wavelength for analysis. Canine synovial fluid and plasma samples were mixed with the 25% vitamin B12 solution to obtain 1%, 3%, 5%, 10%, 20%, and 50% solutions of synovial fluid or plasma. Diluted synovial fluid and plasma samples were used to simulate joint lavage samples and to examine the possible interference of these substances (synovial fluid or plasma) with the absorbance of the 25% vitamin B12 solution in photometric analysis. The optimal wavelength was found to be at 550 nm. Canine synovial fluid and plasma samples did not interfere with the absorbance measurements of the 25% vitamin B12 solution up to a 50% dilution of plasma or synovial fluid. The modified saline solution joint lavage method with the use of a 25% vitamin B12 solution as an internal standard provides an accurate and reliable technique for the evaluation of synovial fluid dilution in lavage samples from canine joints.

Effects of Time and Storage Conditions on the Chemical and Microbiologic Stability of Diluted Buprenorphine for Injection

PubMed Central

DenHerder, Johnathan M; Reed, Ralph L; Sargent, Jennifer L; Bobe, Gerd; Stevens, Jan F; Diggs, Helen E

2017-01-01

Buprenorphine is a partial μ-opioid agonist used for analgesia. Due to the small size of laboratory rodents, buprenorphine HCl is typically diluted 10- or 20-fold with a sterile diluent, such as saline, for accurate dosing. Protocols for preparing and storing diluted buprenorphine vary by institution, and little published information is available regarding stability and beyond-use dating of specific buprenorphine preparations. The purpose of this study was to determine the chemical and microbiologic stability of diluted buprenorphine stored for a maximum of 180 d. Buprenorphine HCl was diluted 1:10 into sterile bacteriostatic saline by using aseptic technique. Diluted samples were stored in glass vials or plastic syringes, protected from light, and maintained at refrigerated or room temperature for as long as 180 d. Aerobic and anaerobic cultures on all stored samples were negative for bacterial and fungal growth. According to HPLC analysis, diluted buprenorphine stored in glass vials experienced less than 10% loss when stored for 180 d at either refrigerated or room temperature. However, the concentration of buprenorphine stored in syringes declined rapidly to more than 80% loss at room temperature and 28% loss in the refrigerator after 180 d. According to the results of this study, diluted buprenorphine stored in glass vials retains more than 90% of the initial concentration and is microbiologically stable for 180 d. However, our data suggest that, regardless of the duration, storing diluted buprenorphine in plastic syringes is inadvisable. PMID:28724496

A Highly Efficient Design Strategy for Regression with Outcome Pooling

PubMed Central

Mitchell, Emily M.; Lyles, Robert H.; Manatunga, Amita K.; Perkins, Neil J.; Schisterman, Enrique F.

2014-01-01

The potential for research involving biospecimens can be hindered by the prohibitive cost of performing laboratory assays on individual samples. To mitigate this cost, strategies such as randomly selecting a portion of specimens for analysis or randomly pooling specimens prior to performing laboratory assays may be employed. These techniques, while effective in reducing cost, are often accompanied by a considerable loss of statistical efficiency. We propose a novel pooling strategy based on the k-means clustering algorithm to reduce laboratory costs while maintaining a high level of statistical efficiency when predictor variables are measured on all subjects, but the outcome of interest is assessed in pools. We perform simulations motivated by the BioCycle study to compare this k-means pooling strategy with current pooling and selection techniques under simple and multiple linear regression models. While all of the methods considered produce unbiased estimates and confidence intervals with appropriate coverage, pooling under k-means clustering provides the most precise estimates, closely approximating results from the full data and losing minimal precision as the total number of pools decreases. The benefits of k-means clustering evident in the simulation study are then applied to an analysis of the BioCycle dataset. In conclusion, when the number of lab tests is limited by budget, pooling specimens based on k-means clustering prior to performing lab assays can be an effective way to save money with minimal information loss in a regression setting. PMID:25220822

A highly efficient design strategy for regression with outcome pooling.

PubMed

Mitchell, Emily M; Lyles, Robert H; Manatunga, Amita K; Perkins, Neil J; Schisterman, Enrique F

2014-12-10

The potential for research involving biospecimens can be hindered by the prohibitive cost of performing laboratory assays on individual samples. To mitigate this cost, strategies such as randomly selecting a portion of specimens for analysis or randomly pooling specimens prior to performing laboratory assays may be employed. These techniques, while effective in reducing cost, are often accompanied by a considerable loss of statistical efficiency. We propose a novel pooling strategy based on the k-means clustering algorithm to reduce laboratory costs while maintaining a high level of statistical efficiency when predictor variables are measured on all subjects, but the outcome of interest is assessed in pools. We perform simulations motivated by the BioCycle study to compare this k-means pooling strategy with current pooling and selection techniques under simple and multiple linear regression models. While all of the methods considered produce unbiased estimates and confidence intervals with appropriate coverage, pooling under k-means clustering provides the most precise estimates, closely approximating results from the full data and losing minimal precision as the total number of pools decreases. The benefits of k-means clustering evident in the simulation study are then applied to an analysis of the BioCycle dataset. In conclusion, when the number of lab tests is limited by budget, pooling specimens based on k-means clustering prior to performing lab assays can be an effective way to save money with minimal information loss in a regression setting. Copyright © 2014 John Wiley & Sons, Ltd.

Estimation method for serial dilution experiments.

PubMed

Ben-David, Avishai; Davidson, Charles E

2014-12-01

Titration of microorganisms in infectious or environmental samples is a corner stone of quantitative microbiology. A simple method is presented to estimate the microbial counts obtained with the serial dilution technique for microorganisms that can grow on bacteriological media and develop into a colony. The number (concentration) of viable microbial organisms is estimated from a single dilution plate (assay) without a need for replicate plates. Our method selects the best agar plate with which to estimate the microbial counts, and takes into account the colony size and plate area that both contribute to the likelihood of miscounting the number of colonies on a plate. The estimate of the optimal count given by our method can be used to narrow the search for the best (optimal) dilution plate and saves time. The required inputs are the plate size, the microbial colony size, and the serial dilution factors. The proposed approach shows relative accuracy well within ±0.1log10 from data produced by computer simulations. The method maintains this accuracy even in the presence of dilution errors of up to 10% (for both the aliquot and diluent volumes), microbial counts between 10(4) and 10(12) colony-forming units, dilution ratios from 2 to 100, and plate size to colony size ratios between 6.25 to 200. Published by Elsevier B.V.

Pinch-off dynamics, extensional viscosity and relaxation time of dilute and ultradilute aqueous polymer solutions

NASA Astrophysics Data System (ADS)

Biagioli, Madeleine; Dinic, Jelena; Jimenez, Leidy Nallely; Sharma, Vivek

Free surface flows and drop formation processes present in printing, jetting, spraying, and coating involve the development of columnar necks that undergo spontaneous surface-tension driven instability, thinning, and pinch-off. Stream-wise velocity gradients that arise within the thinning neck create and extensional flow field, which induces micro-structural changes within complex fluids that contribute elastic stresses, changing the thinning and pinch-off dynamics. In this contribution, we use dripping-onto-substrate (DoS) extensional rheometry technique for visualization and analysis of the pinch-off dynamics of dilute and ultra-dilute aqueous polyethylene oxide (PEO) solutions. Using a range of molecular weights, we study the effect of both elasticity and finite extensibility. Both effective relaxation time and the transient extensional viscosity are found to be strongly concentration-dependent even for highly dilute solutions.

Hyperspectral imaging technique for detection of poultry fecal residues on food processing equipments

NASA Astrophysics Data System (ADS)

Cho, Byoung-Kwan; Kim, Moon S.; Chen, Yud-Ren

2005-11-01

Emerging concerns about safety and security in current mass production of food products necessitate rapid and reliable inspection for contaminant-free products. Diluted fecal residues on poultry processing plant equipment surface, not easily discernable from water by human eye, are contamination sources for poultry carcasses. Development of sensitive detection methods for fecal residues is essential to ensure safe production of poultry carcasses. Hyperspectral imaging techniques have shown good potential for detecting of the presence of fecal and other biological substances on food and processing equipment surfaces. In this study, use of high spatial resolution hyperspectral reflectance and fluorescence imaging (with UV-A excitation) is presented as a tool for selecting a few multispectral bands to detect diluted fecal and ingesta residues on materials used for manufacturing processing equipment. Reflectance and fluorescence imaging methods were compared for potential detection of a range of diluted fecal residues on the surfaces of processing plant equipment. Results showed that low concentrations of poultry feces and ingesta, diluted up to 1:100 by weight with double distilled water, could be detected using hyperspectral fluorescence images with an accuracy of 97.2%. Spectral bands determined in this study could be used for developing a real-time multispectral inspection device for detection of harmful organic residues on processing plant equipment.

Intakes of coffee, tea, milk, soda and juice and renal cell cancer in a pooled analysis of 13 prospective studies.

PubMed

Lee, Jung Eun; Hunter, David J; Spiegelman, Donna; Adami, Hans-Olov; Bernstein, Leslie; van den Brandt, Piet A; Buring, Julie E; Cho, Eunyoung; English, Dallas; Folsom, Aaron R; Freudenheim, Jo L; Gile, Graham G; Giovannucci, Edward; Horn-Ross, Pamela L; Leitzmann, Michael; Marshall, James R; Männistö, Satu; McCullough, Marjorie L; Miller, Anthony B; Parker, Alexander S; Pietinen, Pirjo; Rodriguez, Carmen; Rohan, Thomas E; Schatzkin, Arthur; Schouten, Leo J; Willett, Walter C; Wolk, Alicja; Zhang, Shumin M; Smith-Warner, Stephanie A

2007-11-15

Specific beverage intake may be associated with the risk of renal cell cancer through a diluting effect of carcinogens, alterations of hormone levels, or other changes in the renal tubular environment, but few prospective studies have examined these associations. We evaluated the associations between coffee, tea, milk, soda and fruit and vegetable juice intakes and renal cell cancer risk in a pooled analysis of 13 prospective studies (530,469 women and 244,483 men). Participants completed a validated food-frequency questionnaire at baseline. Using the primary data, the study-specific relative risks (RRs) were calculated and then pooled using a random effects model. A total of 1,478 incident renal cell cancer cases were identified during a follow-up of 7-20 years across studies. Coffee consumption was associated with a modestly lower risk of renal cell cancer (pooled multivariate RR for 3 or more 8 oz (237 ml) cups/day versus less than one 8 oz (237 ml) cup/day = 0.84; 95% CI = 0.67-1.05; p value, test for trend = 0.22). Tea consumption was also inversely associated with renal cell cancer risk (pooled multivariate RR for 1 or more 8 oz (237 ml) cups/day versus nondrinkers = 0.85; 95% CI = 0.71-1.02; pvalue, test for trend = 0.04). No clear associations were observed for milk, soda or juice. Our findings provide strong evidence that neither coffee nor tea consumption increases renal cell cancer risk. Instead, greater consumption of coffee and tea may be associated with a lower risk of renal cell cancer. (c) 2007 Wiley-Liss, Inc. (c) 2007 Wiley-Liss, Inc.

Combined use of fluorescence with a magnetic tracer and dilution effect upon sentinel node localization in a murine model.

PubMed

Kuwahata, Akihiro; Ahmed, Muneer; Saeki, Kohei; Chikaki, Shinichi; Kaneko, Miki; Qiu, Wenqi; Xin, Zonghao; Yamaguchi, Shinji; Kaneko, Akiko; Douek, Michael; Kusakabe, Moriaki; Sekino, Masaki

2018-01-01

Sentinel node biopsy using radioisotope and blue dye remains a gold standard for axillary staging in breast cancer patients with low axillary burden. However, limitations in the use of radioisotopes have resulted in emergence of novel techniques. This is the first in vivo study to assess the feasibility of combining the two most common novel techniques of using a magnetic tracer and indocyanine green (ICG) fluorescence. A total of 48 mice were divided into eight groups. Groups 1 and 2, the co-localization groups, received an injection of magnetic tracers (Resovist ® and Sienna+ ® , respectively) and ICG fluorescence; distilled water was used as the solvent of ICG. Groups 3 and 4, the diluted injection groups, received an injection of magnetic tracers (Resovist and Sienna+, respectively) and saline for dilution. Groups 5, 6, and 7, the control groups, received magnetic tracer (Resovist, Sienna+) and ICG alone, respectively. Fluorescent intensity assessment and iron quantification of excised popliteal lymph nodes were performed. Group 1', a co-localization group, received an injection of magnetic tracers (Resovist) and ICG' fluorescence: saline was used as the solvent for ICG. Lymphatic uptake of all tracers was confined to the popliteal nodes only, with co-localization confirmed in all cases and no significant difference in fluorescent intensity or iron content of ex vivo nodes between the groups (except for Group 1'). There was no impact of dilution on the iron content in the diluted Sienna+ group, but it significantly enhanced Resovist uptake ( P =0.005). In addition, there was a significant difference in iron content ( P =0.003) in Group 1'. The combination of a magnetic tracer (Resovist or Sienna+) and ICG fluorescence is feasible for sentinel node biopsy and will potentially allow for precise transcutaneous node identification, in addition to accurate intraoperative assessment. This radioisotope-free "combined technique" warrants further assessment within a clinical trial.

Diagnosis of deep endometriosis: clinical examination, ultrasonography, magnetic resonance imaging, and other techniques.

PubMed

Bazot, Marc; Daraï, Emile

2017-12-01

The aim of the present review was to evaluate the contribution of clinical examination and imaging techniques, mainly transvaginal sonography and magnetic resonance imaging (MRI) to diagnose deep infiltrating (DE) locations using prisma statement recommendations. Clinical examination has a relative low sensitivity and specificity to diagnose DE. Independently of DE locations, for all transvaginal sonography techniques a pooled sensitivity and specificity of 79% and 94% are observed approaching criteria for a triage test. Whatever the protocol and MRI devices, the pooled sensitivity and specificity for pelvic endometriosis diagnosis were 94% and 77%, respectively. For rectosigmoid endometriosis, pooled sensitivity and specificity of MRI were 92% and 96%, respectively fulfilling criteria of replacement test. In conclusion, advances in imaging techniques offer high sensitivity and specificity to diagnose DE with at least triage value and for rectosigmoid endometriosis replacement value imposing a revision of the concept of laparoscopy as the gold standard. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Single Particle-Inductively Coupled Plasma Mass Spectroscopy Analysis of Metallic Nanoparticles in Environmental Samples with Large Dissolved Analyte Fractions.

PubMed

Schwertfeger, D M; Velicogna, Jessica R; Jesmer, Alexander H; Scroggins, Richard P; Princz, Juliska I

2016-10-18

There is an increasing interest to use single particle-inductively coupled plasma mass spectroscopy (SP-ICPMS) to help quantify exposure to engineered nanoparticles, and their transformation products, released into the environment. Hindering the use of this analytical technique for environmental samples is the presence of high levels of dissolved analyte which impedes resolution of the particle signal from the dissolved. While sample dilution is often necessary to achieve the low analyte concentrations necessary for SP-ICPMS analysis, and to reduce the occurrence of matrix effects on the analyte signal, it is used here to also reduce the dissolved signal relative to the particulate, while maintaining a matrix chemistry that promotes particle stability. We propose a simple, systematic dilution series approach where by the first dilution is used to quantify the dissolved analyte, the second is used to optimize the particle signal, and the third is used as an analytical quality control. Using simple suspensions of well characterized Au and Ag nanoparticles spiked with the dissolved analyte form, as well as suspensions of complex environmental media (i.e., extracts from soils previously contaminated with engineered silver nanoparticles), we show how this dilution series technique improves resolution of the particle signal which in turn improves the accuracy of particle counts, quantification of particulate mass and determination of particle size. The technique proposed here is meant to offer a systematic and reproducible approach to the SP-ICPMS analysis of environmental samples and improve the quality and consistency of data generated from this relatively new analytical tool.

Influence of Post-Mortem Sperm Recovery Method and Extender on Unstored and Refrigerated Rooster Sperm Variables.

PubMed

Villaverde-Morcillo, S; Esteso, M C; Castaño, C; Santiago-Moreno, J

2016-02-01

Many post-mortem sperm collection techniques have been described for mammalian species, but their use in birds is scarce. This paper compares the efficacy of two post-mortem sperm retrieval techniques - the flushing and float-out methods - in the collection of rooster sperm, in conjunction with the use of two extenders, i.e., L&R-84 medium and Lake 7.1 medium. To determine whether the protective effects of these extenders against refrigeration are different for post-mortem and ejaculated sperm, pooled ejaculated samples (procured via the massage technique) were also diluted in the above extenders. Post-mortem and ejaculated sperm variables were assessed immediately at room temperature (0 h), and after refrigeration at 5°C for 24 and 48 h. The flushing method retrieved more sperm than the float-out method (596.5 ± 75.4 million sperm vs 341.0 ± 87.6 million sperm; p < 0.05); indeed, the number retrieved by the former method was similar to that obtained by massage-induced ejaculation (630.3 ± 78.2 million sperm). For sperm collected by all methods, the L&R-84 medium provided an advantage in terms of sperm motility variables at 0 h. In the refrigerated sperm samples, however, the Lake 7.1 medium was associated with higher percentages of viable sperm, and had a greater protective effect (p < 0.05) with respect to most motility variables. In conclusion, the flushing method is recommended for collecting sperm from dead birds. If this sperm needs to be refrigerated at 5°C until analysis, Lake 7.1 medium is recommended as an extender. © 2015 Blackwell Verlag GmbH.

Impact of different dilution techniques on boar sperm quality and sperm distribution of the extended ejaculate.

PubMed

Schulze, M; Ammon, C; Schaefer, J; Luther, A-M; Jung, M; Waberski, D

2017-07-01

The dilution of ejaculates is a fundamental step for the production of liquid-preserved boar semen. For a long time, it has been recommended to add the extender to the ejaculate. The aim of the present study was to first compare the effect of the position ('center' vs. 'wall') where the extender is added to the semen-mixing cylinder (height 32.5cm; diameter 12.7cm) using an automatic dispenser (n=11). In experiment 2 (n=30), we analyzed the two main dilution methods (extender to the semen ('control') vs. 'reverse'). Experiment 3 was carried out to study the dilution effect on kinematics. In Experiments 1 and 2, the sperm distribution 10min after the dilution and the sperm quality parameters during long-term storage (d1, d3, d5, and d7) were evaluated. In Experiment 3, sperm quality was assessed during short-term storage at 0, 10, 20, 30 and 60min after semen dilution ('control' vs. 'reverse'; n=6). There were no significant differences (P>0.05) between the treatments in the specific response to bicarbonate, mitochondrial activity, membrane status, thermo-resistance or sperm motility immediately after dilution or long-term storage. The sperm distribution was significantly (P=0.029) affected by the dilution method in Experiment 2. In summary, treatment with the extender first, which is used by only a few European boar studs, leads to comparable results in sperm quality during storage and better results in sperm distribution after dilution. This procedure is also less time consuming, less foam formation occurs during the semen dilution and the procedure is more hygienic. Copyright © 2017 Elsevier B.V. All rights reserved.

Turnover of cyclic 2,3-diphosphoglycerate in Methanobacterium thermoautotrophicum. Phosphate flux in P1- and H2-limited chemostat cultures.

PubMed

Krueger, R D; Campbell, J W; Fahrney, D E

1986-09-15

The archaebacterium Methanobacterium thermoautotrophicum was grown at 65 degrees C in H2- and Pi-limited chemostat cultures at dilution rates corresponding to 3- and 4-h doubling times, respectively. Under these conditions the steady state concentration of cyclic 2,3-diphosphoglycerate was 44 mM in the H2-limited cells and 13 mM in the cells grown under Pi limitation. Flux of Pi into the cyclic pyrophosphate pool was estimated by two 32P-labeling procedures: approach to isotopic equilibrium and replacement of prelabeled cyclic diphosphoglycerate with unlabeled compound. The results unequivocally demonstrate turnover of the phosphoryl groups; either both phosphoryl groups of the cyclic pyrophosphate leave together or the second leaves at a faster rate. The half-life of the rate-determining step for loss of the phosphoryl groups was approximately equal to the culture doubling time. The Pi flowing into the cyclic diphosphoglycerate pool accounted for 19% of the total Pi flux into Pi-limited cells and 43% of the total for H2-limited cells. The high phosphate flux through the large cyclic diphosphoglycerate pool suggests that this molecule plays an important role in the phosphorus metabolism of this methanogen.

Use of pooled samples to assess human exposure to parabens, benzophenone-3 and triclosan in Queensland, Australia

PubMed Central

Heffernan, A.L.; Baduel, C.; Toms, L.M.L.; Calafat, A.M.; Ye, X.; Hobson, P.; Broomhall, S.; Mueller, J.F.

2017-01-01

Parabens, benzophenone-3 and triclosan are common ingredients used as preservatives, ultraviolet radiation filters and antimicrobial agents, respectively. Human exposure occurs through consumption of processed food and use of cosmetics and consumer products. The aim of this study was to provide a preliminary characterisation of exposure to selected personal care product chemicals in the general Australian population. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n = 24 pools of 100). Concentrations of free and total (sum of free plus conjugated) species of methyl, ethyl, propyl and butyl paraben, benzophenone-3 and triclosan were quantified using isotope dilution tandem mass spectrometry; with geometric means 232, 33.5, 60.6, 4.32, 61.5 and 87.7 ng/mL, respectively. Age was inversely associated with paraben concentration, and females had concentrations approximately two times higher than males. Total paraben and benzophenone-3 concentrations are significantly higher than reported worldwide, and the average triclosan concentration was more than one order of magnitude higher than in many other populations. This study provides the first data on exposure of the general Australian population to a range of common personal care product chemical ingredients, which appears to be prevalent and warrants further investigation. PMID:26368661

Fabrication of Copper-Rich Cu-Al Alloy Using the Wire-Arc Additive Manufacturing Process

NASA Astrophysics Data System (ADS)

Dong, Bosheng; Pan, Zengxi; Shen, Chen; Ma, Yan; Li, Huijun

2017-12-01

An innovative wire-arc additive manufacturing (WAAM) process is used to fabricate Cu-9 at. pct Al on pure copper plates in situ, through separate feeding of pure Cu and Al wires into a molten pool, which is generated by the gas tungsten arc welding (GTAW) process. After overcoming several processing problems, such as opening the deposition molten pool on the extremely high-thermal conductive copper plate and conducting the Al wire into the molten pool with low feed speed, the copper-rich Cu-Al alloy was successfully produced with constant predesigned Al content above the dilution-affected area. Also, in order to homogenize the as-fabricated material and improve the mechanical properties, two further homogenization heat treatments at 1073 K (800 °C) and 1173 K (900 °C) were applied. The material and mechanical properties of as-fabricated and heat-treated samples were compared and analyzed in detail. With increased annealing temperatures, the content of precipitate phases decreased and the samples showed gradual improvements in both strength and ductility with little variation in microstructures. The present research opened a gate for in-situ fabrication of Cu-Al alloy with target chemical composition and full density using the additive manufacturing process.

Effect of rainbow trout (Oncorhynchus mykiss) seminal plasma on the post-thaw quality of ram semen cryopreserved in a soybean lecithin-based or egg yolk-based extender.

PubMed

Ustuner, Burcu; Alcay, Selim; Toker, M Berk; Nur, Zekariya; Gokce, Elif; Sonat, Fusun Ak; Gul, Zulfiye; Duman, Muhammed; Ceniz, Cafer; Uslu, Aydın; Sagirkaya, Hakan; Soylu, M Kemal

2016-01-01

The aim of the current study was to evaluate the effects of different concentrations of rainbow trout seminal plasma (RTSP) (0.1%, 1% and 10%) in extenders containing either egg yolk or lecithin for use in Awassi ram semen cryopreservation. Pooled sperm were diluted in a two-step dilution method to a final concentration of 1/5 (semen/extender) in egg yolk or lecithin extender containing no RTSP, 0.1%, 1% or 10% RTSP (v/v). Semen samples were assessed for sperm motility, plasma membrane integrity [hypoosmotic swelling test (HOST) and Hoechst 33258] and defective acrosomes [FITC-conjugated Pisum sativum agglutinin (PSA-FITC)] at the following five time points: after dilution with extender A; after equilibration; and post-thaw at 0h, 3h and 5h. Malondialdehyde (MDA) was examined only after thawing. Freezing and thawing procedures (dilution, equilibration and post-thaw incubation at 0h, 3h and 5h) negatively affected the motility (P<0.001) and acrosome integrity (P<0.001). Additionally, freezing and thawing negatively affected the plasma membrane integrity, as determined by the HOST and Hoechst 33258 (P<0.001). The extender group affected the motility (P<0.001) and the HOST results (P<0.001). Levels of MDA in the egg yolk extender with 1% RTSP group were significantly lower than in the lecithin control group (P<0.05). In conclusion, the egg yolk extender groups that were supplemented with 10% and 1% RTSP provided greater cryoprotective effects for semen survivability during 5h incubation than the other extender groups. Copyright © 2015 Elsevier B.V. All rights reserved.

False-positive pregnancy test after transfusion of solvent/detergent-treated plasma.

PubMed

Jilma-Stohlawetz, Petra; Wreford-Bush, Tim; Mills, Francesca; Davidson, Fiona; Kursten, Friedrich W; Jilma, Bernd; Birchall, Janet

2017-12-01

The transmission of pathogens, antibodies, and proteins is a possible consequence of blood product transfusion. A female patient had an unexpected positive serum β-human chorionic gonadotropin result, indicative of pregnancy, after she had received a transfusion with 1 unit of platelet concentrate, 4 units of red blood cells, and 4 units of pooled solvent/detergent-treated plasma (Octaplas). To investigate the possibility of passive transfusion of β-human chorionic gonadotropin from the plasma transfusion, one additional unit from the same batch was thawed and analyzed. To validate the β-human chorionic gonadotropin assay for use in solvent/detergent-treated plasma and to investigate any interference in the assay, dilution experiments were performed using the implicated plasma batch diluted with male and non-pregnant female sera. Also, plasma from a known pregnant woman was diluted with Octaplas (tested negative for β-human chorionic gonadotropin) and with a male serum to validate the assay for use in solvent/detergent-treated plasma. The implicated solvent/detergent-treated plasma had a mean β-human chorionic gonadotropin level of 91.5 mIU/mL. Results from the dilution experiments revealed an excellent correlation (r > 0.99) between β-human chorionic gonadotropin measurement in solvent/detergent-treated plasma and male serum and no over or under recovery of the expected results. Further measurements of β-human chorionic gonadotropin levels in the female recipient revealed an estimated half-life of 6 hours. This case demonstrates the importance of considering the possibility of passive transmission of analytes to a patient from the transfusion of blood products. Furthermore, the measurement of β-human chorionic gonadotropin is valid in solvent/detergent-treated plasma using a Roche Cobas analyzer. © 2017 AABB.

SKELETAL DYNAMICS IN MAN MEASURED BY NONRADIOACTIVE STRONTIUM

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

Eisenberg, E.; Gordan, G.S.

Skeletal dynamics were calculated by usual dilution formulas, using stable strontium as a tracer, in 25 normal subjects, 14 athletes, 26 patients with postmenopausal osteoporosis, 28 with primary hyperparathyroidism, 3 with hyperadrenocorticism 8 with acromegaly, 7 with thyrotoxicosis, 11 with urclithiasis, 5 with Paget's disease of bone. and 1 with vitamin D poisoning. The technic requires that 10 mEq of strontium gluconate be injected intravenously and blood and urine concentrations be measured for 4 to 6 days. In normal subjects the rapidly miscible pool was equivalent to 42.7 + 1.1 L of serum, turning over at a rate of 13.5more » plus or minus 0.6 L daily, of which 3.9 + 0.2 L was excreted by the kidney and 9.6 + 0.4 L went to bone. Since only approximately 2.5% of the pool is excreted in the feces daily, fecal excretion was not measured routinely. Good reproducibility was found in 21 duplicate studies. Intense muscular exercise (athletes) was found to expand the pool greatly and to accelerate the rate of deposition in bone. Kinetically, two divergent types of osteoporosis were differentiated. A small pool and low rate of bone deposition were found in postmenopausal osteoporosis and Cushing's disease of long duration. The large pool and rapid rate of bone deposition in thyrotoxicosis was confirmed and also found in acromegaly. In these two, excessive bone resorption is postulated. Urinary excretion rate was excessive in Cushing's disease, thyrotoxicosis, and acromegaly. In hyperparathyroidism with clinically evident osteitis, expanded pools, greatly increased turnover, urinary excretion, and bone deposition rates were confirmed. In patients with normal roentgenographic appearance and phosphatase, bone involvement was shown by slight increase in bone deposition rate and microscopic foci of resorption on iliac crest biopsy. In seven patients without histological foci of resorption, the bone deposition rate was not increased. (auth)« less

Apoplastic water fraction and rehydration techniques introduce significant errors in measurements of relative water content and osmotic potential in plant leaves.

PubMed

Arndt, Stefan K; Irawan, Andi; Sanders, Gregor J

2015-12-01

Relative water content (RWC) and the osmotic potential (π) of plant leaves are important plant traits that can be used to assess drought tolerance or adaptation of plants. We estimated the magnitude of errors that are introduced by dilution of π from apoplastic water in osmometry methods and the errors that occur during rehydration of leaves for RWC and π in 14 different plant species from trees, grasses and herbs. Our data indicate that rehydration technique and length of rehydration can introduce significant errors in both RWC and π. Leaves from all species were fully turgid after 1-3 h of rehydration and increasing the rehydration time resulted in a significant underprediction of RWC. Standing rehydration via the petiole introduced the least errors while rehydration via floating disks and submerging leaves for rehydration led to a greater underprediction of RWC. The same effect was also observed for π. The π values following standing rehydration could be corrected by applying a dilution factor from apoplastic water dilution using an osmometric method but not by using apoplastic water fraction (AWF) from pressure volume (PV) curves. The apoplastic water dilution error was between 5 and 18%, while the two other rehydration methods introduced much greater errors. We recommend the use of the standing rehydration method because (1) the correct rehydration time can be evaluated by measuring water potential, (2) overhydration effects were smallest, and (3) π can be accurately corrected by using osmometric methods to estimate apoplastic water dilution. © 2015 Scandinavian Plant Physiology Society.

Characterizing convective cold pools: Characterizing Convective Cold Pools

DOE PAGES

Drager, Aryeh J.; van den Heever, Susan C.

2017-05-09

Cold pools produced by convective storms play an important role in Earth's climate system. However, a common framework does not exist for objectively identifying convective cold pools in observations and models. The present study investigates convective cold pools within a simulation of tropical continental convection that uses a cloud-resolving model with a coupled land-surface model. Multiple variables are assessed for their potential in identifying convective cold pool boundaries, and a novel technique is developed and tested for identifying and tracking cold pools in numerical model simulations. This algorithm is based on surface rainfall rates and radial gradients in the densitymore » potential temperature field. The algorithm successfully identifies near-surface cold pool boundaries and is able to distinguish between connected cold pools. Once cold pools have been identified and tracked, composites of cold pool evolution are then constructed, and average cold pool properties are investigated. Wet patches are found to develop within the centers of cold pools where the ground has been soaked with rainwater. These wet patches help to maintain cool surface temperatures and reduce cold pool dissipation, which has implications for the development of subsequent convection.« less

Characterizing convective cold pools: Characterizing Convective Cold Pools

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

Drager, Aryeh J.; van den Heever, Susan C.

Cold pools produced by convective storms play an important role in Earth's climate system. However, a common framework does not exist for objectively identifying convective cold pools in observations and models. The present study investigates convective cold pools within a simulation of tropical continental convection that uses a cloud-resolving model with a coupled land-surface model. Multiple variables are assessed for their potential in identifying convective cold pool boundaries, and a novel technique is developed and tested for identifying and tracking cold pools in numerical model simulations. This algorithm is based on surface rainfall rates and radial gradients in the densitymore » potential temperature field. The algorithm successfully identifies near-surface cold pool boundaries and is able to distinguish between connected cold pools. Once cold pools have been identified and tracked, composites of cold pool evolution are then constructed, and average cold pool properties are investigated. Wet patches are found to develop within the centers of cold pools where the ground has been soaked with rainwater. These wet patches help to maintain cool surface temperatures and reduce cold pool dissipation, which has implications for the development of subsequent convection.« less

A method for measuring particle number emissions from vehicles driving on the road.

PubMed

Shi, J P; Harrison, R M; Evans, D E; Alam, A; Barnes, C; Carter, G

2002-01-01

Earlier research has demonstrated that the conditions of dilution of engine exhaust gases profoundly influence the size distribution and total number of particles emitted. Since real world dilution conditions are variable and therefore difficult to simulate, this research has sought to develop and validate a method for measuring particle number emissions from vehicles driving past on a road. This has been achieved successfully using carbon dioxide as a tracer of exhaust gas dilution. By subsequent adjustment of data to a constant dilution factor, it is possible to compare emissions from different vehicles using different technologies and fuels based upon real world emission data. Whilst further optimisation of the technique, especially in terms of matching the instrument response times is desirable, the measurements offer useful insights into emissions from gasoline and diesel vehicles, and the substantial proportion of particles emitted in the 3-7 nanometre size range.

Improving Estimates and Forecasts of Lake Carbon Pools and Fluxes Using Data Assimilation

NASA Astrophysics Data System (ADS)

Zwart, J. A.; Hararuk, O.; Prairie, Y.; Solomon, C.; Jones, S.

2017-12-01

Lakes are biogeochemical hotspots on the landscape, contributing significantly to the global carbon cycle despite their small areal coverage. Observations and models of lake carbon pools and fluxes are rarely explicitly combined through data assimilation despite significant use of this technique in other fields with great success. Data assimilation adds value to both observations and models by constraining models with observations of the system and by leveraging knowledge of the system formalized by the model to objectively fill information gaps. In this analysis, we highlight the utility of data assimilation in lake carbon cycling research by using the Ensemble Kalman Filter to combine simple lake carbon models with observations of lake carbon pools. We demonstrate the use of data assimilation to improve a model's representation of lake carbon dynamics, to reduce uncertainty in estimates of lake carbon pools and fluxes, and to improve the accuracy of carbon pool size estimates relative to estimates derived from observations alone. Data assimilation techniques should be embraced as valuable tools for lake biogeochemists interested in learning about ecosystem dynamics and forecasting ecosystem states and processes.

A survey of techniques for refrigeration, reliquefaction, and production of slush for hydrogen

NASA Technical Reports Server (NTRS)

Overcash, Dan R.

1990-01-01

Several techniques were surveyed for the refrigeration, reliquefaction and production of slush from hydrogen. The techniques included auger; bubbling helium gas; Simon desorption; the Petlier effect; Joule-Kelvin expansion using Stirling, Brayton, and Viulleumirer approaches; rotary reciprocating; a dilution refrigerator; adiabatic demagnetization of a paramagnetic salt; and adiabatic magnetization of a superconductor.

Orientation masking and cross-orientation suppression (XOS): implications for estimates of filter bandwidth.

PubMed

Meese, Tim S; Holmes, David J

2010-10-01

Most contemporary models of spatial vision include a cross-oriented route to suppression (masking from a broadly tuned inhibitory pool), which is most potent at low spatial and high temporal frequencies (T. S. Meese & D. J. Holmes, 2007). The influence of this pathway can elevate orientation-masking functions without exciting the target mechanism, and because early psychophysical estimates of filter bandwidth did not accommodate this, it is likely that they have been overestimated for this corner of stimulus space. Here we show that a transient 40% contrast mask causes substantial binocular threshold elevation for a transient vertical target, and this declines from a mask orientation of 0° to about 40° (indicating tuning), and then more gently to 90°, where it remains at a factor of ∼4. We also confirm that cross-orientation masking is diminished or abolished at high spatial frequencies and for sustained temporal modulation. We fitted a simple model of pedestal masking and cross-orientation suppression (XOS) to our data and those of G. C. Phillips and H. R. Wilson (1984) and found the dependency of orientation bandwidth on spatial frequency to be much less than previously supposed. An extension of our linear spatial pooling model of contrast gain control and dilution masking (T. S. Meese & R. J. Summers, 2007) is also shown to be consistent with our results using filter bandwidths of ±20°. Both models include tightly and broadly tuned components of divisive suppression. More generally, because XOS and/or dilution masking can affect the shape of orientation-masking curves, we caution that variations in bandwidth estimates might reflect variations in processes that have nothing to do with filter bandwidth.

Comparison of Glutamate Turnover in Nerve Terminals and Brain Tissue During [1,6-13C2]Glucose Metabolism in Anesthetized Rats.

PubMed

Patel, Anant B; Lai, James C K; Chowdhury, Golam I M; Rothman, Douglas L; Behar, Kevin L

2017-01-01

The 13 C turnover of neurotransmitter amino acids (glutamate, GABA and aspartate) were determined from extracts of forebrain nerve terminals and brain homogenate, and fronto-parietal cortex from anesthetized rats undergoing timed infusions of [1,6- 13 C 2 ]glucose or [2- 13 C]acetate. Nerve terminal 13 C fractional labeling of glutamate and aspartate was lower than those in whole cortical tissue at all times measured (up to 120 min), suggesting either the presence of a constant dilution flux from an unlabeled substrate or an unlabeled (effectively non-communicating on the measurement timescale) glutamate pool in the nerve terminals. Half times of 13 C labeling from [1,6- 13 C 2 ]glucose, as estimated by least squares exponential fitting to the time course data, were longer for nerve terminals (Glu C4 , 21.8 min; GABA C2 21.0 min) compared to cortical tissue (Glu C4 , 12.4 min; GABA C2 , 14.5 min), except for Asp C3 , which was similar (26.5 vs. 27.0 min). The slower turnover of glutamate in the nerve terminals (but not GABA) compared to the cortex may reflect selective effects of anesthesia on activity-dependent glucose use, which might be more pronounced in the terminals. The 13 C labeling ratio for glutamate-C4 from [2- 13 C]acetate over that of 13 C-glucose was twice as large in nerve terminals compared to cortex, suggesting that astroglial glutamine under the 13 C glucose infusion was the likely source of much of the nerve terminal dilution. The net replenishment of most of the nerve terminal amino acid pools occurs directly via trafficking of astroglial glutamine.

Cryopreservation of ram semen with antioxidant supplemented soybean lecithin-based extenders and impacts on incubation resilience.

PubMed

Toker, M Berk; Alcay, Selim; Gokce, Elif; Ustuner, Burcu

2016-06-01

The scope of this study was investigation the affects of various antioxidants on 1% soybean lecithin-based semen extenders for ram semen cryopreservation. Ejaculates, collected via electrically stimulated ejaculation, that have a thick consistency, rapid wave motion (3-5 on a 0-5 scale) and >75% initial motility were pooled. The pooled samples were split into four equal aliquots as 5 mM Methionine, 5 mM Cysteamine, 1 mM Cysteine and a sample of antioxidant-free control group. Each sample group was diluted to a ratio of 1/5 (semen/extender, v/v) as final concentration and two step dilution method was used for cryopreservation. Extender groups were assessed for sperm motility, plasma membrane functional integrity using hypoosmotic swelling test (HOST), damaged acrosome using FITC-Pisum sativum agglutinin (PSA-FITC) and DNA integrity using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Semen samples also incubated for 6 h in humidified air with 5% CO2 at 39 °C to evaluate post-thaw incubation resilience of semen characteristics. The results showed that freezing and thawing procedures had negative effects on motility (P < 0.05), plasma membrane integrity (P < 0.05) and acrosomal integrity (P < 0.05). After 6 h of incubation time, the Cysteine supplemented extender group yielded significantly higher results than other extender groups in terms of spermatological parameters. Furthermore MDA levels in the antioxidant groups were lower than control group (P < 0.05). Nevertheless, there were no significant differences among antioxidant groups. Copyright © 2016 Elsevier Inc. All rights reserved.

Revisiting N2 fixation in Guerrero Negro intertidal microbial mats with a functional single-cell approach

PubMed Central

Woebken, Dagmar; Burow, Luke C; Behnam, Faris; Mayali, Xavier; Schintlmeister, Arno; Fleming, Erich D; Prufert-Bebout, Leslie; Singer, Steven W; Cortés, Alejandro López; Hoehler, Tori M; Pett-Ridge, Jennifer; Spormann, Alfred M; Wagner, Michael; Weber, Peter K; Bebout, Brad M

2015-01-01

Photosynthetic microbial mats are complex, stratified ecosystems in which high rates of primary production create a demand for nitrogen, met partially by N2 fixation. Dinitrogenase reductase (nifH) genes and transcripts from Cyanobacteria and heterotrophic bacteria (for example, Deltaproteobacteria) were detected in these mats, yet their contribution to N2 fixation is poorly understood. We used a combined approach of manipulation experiments with inhibitors, nifH sequencing and single-cell isotope analysis to investigate the active diazotrophic community in intertidal microbial mats at Laguna Ojo de Liebre near Guerrero Negro, Mexico. Acetylene reduction assays with specific metabolic inhibitors suggested that both sulfate reducers and members of the Cyanobacteria contributed to N2 fixation, whereas 15N2 tracer experiments at the bulk level only supported a contribution of Cyanobacteria. Cyanobacterial and nifH Cluster III (including deltaproteobacterial sulfate reducers) sequences dominated the nifH gene pool, whereas the nifH transcript pool was dominated by sequences related to Lyngbya spp. Single-cell isotope analysis of 15N2-incubated mat samples via high-resolution secondary ion mass spectrometry (NanoSIMS) revealed that Cyanobacteria were enriched in 15N, with the highest enrichment being detected in Lyngbya spp. filaments (on average 4.4 at% 15N), whereas the Deltaproteobacteria (identified by CARD-FISH) were not significantly enriched. We investigated the potential dilution effect from CARD-FISH on the isotopic composition and concluded that the dilution bias was not substantial enough to influence our conclusions. Our combined data provide evidence that members of the Cyanobacteria, especially Lyngbya spp., actively contributed to N2 fixation in the intertidal mats, whereas support for significant N2 fixation activity of the targeted deltaproteobacterial sulfate reducers could not be found. PMID:25303712

Revisiting N 2 fixation in Guerrero Negro intertidal microbial mats with a functional single-cell approach

DOE PAGES

Woebken, Dagmar; Burow, Luke C.; Behnam, Faris; ...

2014-10-10

Photosynthetic microbial mats are complex, stratified ecosystems in which high rates of primary production create a demand for nitrogen, met partially by N 2 fixation. Dinitrogenase reductase ( nifH) genes and transcripts from Cyanobacteria and heterotrophic bacteria (for example, Deltaproteobacteria) were detected in these mats, yet their contribution to N 2 fixation is poorly understood. We used a combined approach of manipulation experiments with inhibitors, nifH sequencing and single-cell isotope analysis to investigate the active diazotrophic community in intertidal microbial mats at Laguna Ojo de Liebre near Guerrero Negro, Mexico. Acetylene reduction assays with specific metabolic inhibitors suggested that bothmore » sulfate reducers and members of the Cyanobacteria contributed to N 2 fixation, whereas 15N 2 tracer experiments at the bulk level only supported a contribution of Cyanobacteria. Cyanobacterial and nifH Cluster III (including deltaproteobacterial sulfate reducers) sequences dominated the nifH gene pool, whereas the nifH transcript pool was dominated by sequences related to Lyngbya spp. Single-cell isotope analysis of 15N 2-incubated mat samples via high-resolution secondary ion mass spectrometry (NanoSIMS) revealed that Cyanobacteria were enriched in 15N, with the highest enrichment being detected in Lyngbya spp. filaments (on average 4.4 at% 15N), whereas the Deltaproteobacteria (identified by CARD-FISH) were not significantly enriched. We investigated the potential dilution effect from CARD-FISH on the isotopic composition and concluded that the dilution bias was not substantial enough to influence our conclusions. As a result, our combined data provide evidence that members of the Cyanobacteria, especially Lyngbya spp., actively contributed to N 2 fixation in the intertidal mats, whereas support for significant N 2 fixation activity of the targeted deltaproteobacterial sulfate reducers could not be found.« less

Pentoxifylline added to freezing or post-thaw extenders does not improve the survival or in vitro fertilising capacity of boar spermatozoa.

PubMed

Gil, María A; Hernandez, Marta; Roca, Jordi; Almiñana, Carmen; Lucas, Xiomara; Cuello, Cristina; Vazquez, Juan M; Martínez, Emilio A

2010-03-01

This study evaluated whether pentoxifylline added to freezing and thawing extenders influenced the function of boar spermatozoa. In Experiment 1, pooled ejaculated sperm-rich fractions were frozen in 0.5 ml straws after dilution in extender supplemented with pentoxifylline to a final concentration of 0, 2, 4, 8, 16 or 32 mM. The addition of 4, 8, 16 and 32 mM pentoxifylline to the freezing extender significantly decreased the progressive and total motility of spermatozoa. The percentage of viable spermatozoa with intact acrosomes as well as the penetration rate and the efficiency of fertilisation were significantly lower in pentoxifylline-treated groups compared with the untreated control. In Experiment 2, a pool of three straws with 'good' post-thaw sperm quality parameters and another three straws with 'poor' sperm quality were diluted in extender with 0, 1, 2, 4, 8, 16 or 32 mM pentoxifylline. Post-thaw samples with both 'good' and 'poor' sperm quality with 0, 2, 4, 8 and 16 mM were used to assess IVF parameters. The addition of pentoxifylline to post-thaw extender did not improve the post-thaw motility or viability of spermatozoa compared with the control. The in vitro penetration was higher (P<0.05) than the control for oocytes fertilised with spermatozoa that were thawed and incubated in extender with 4, 8 and 16 mM pentoxifylline. However, no differences were observed in the efficiency of fertilisation. We conclude that pentoxifylline, as a supplement added to the freezing extender, has a deleterious effect and that it does not improve the survival or in vitro fertilising efficiency of frozen-thawed boar spermatozoa when added after thawing.

Chemical measurement of urine volume

NASA Technical Reports Server (NTRS)

Sauer, R. L.

1978-01-01

Chemical method of measuring volume of urine samples using lithium chloride dilution technique, does not interfere with analysis, is faster, and more accurate than standard volumetric of specific gravity/weight techniques. Adaptation of procedure to urinalysis could prove generally practical for hospital mineral balance and catechoamine determinations.

Microbial structural diversity estimated by dilution-extinction of phenotypic traits and T-RFLP analysis along a land-use intensification gradient

NASA Technical Reports Server (NTRS)

Gomez, Elena del V.; Garland, Jay L.; Roberts, Michael S.

2004-01-01

The present work tested whether the relationship between functional traits and inoculum density reflected structural diversity in bacterial communities from a land-use intensification gradient applying a mathematical model. Terminal restriction fragment length polymorphism (T-RFLP) analysis was also performed to provide an independent assessment of species richness. Successive 10-fold dilutions of a soil suspension were inoculated onto Biolog GN(R) microplates. Soil bacterial density was determined by total cell and plate counts. The relationship between phenotypic traits and inoculum density fit the model, allowing the estimation of maximal phenotypic potential (Rmax) and inoculum density (KI) at which Rmax will be half-reduced. Though Rmax decreased with time elapsed since clearing of native vegetation, KI remained high in two of the disturbed sites. The genetic pool of bacterial community did not experience a significant reduction, but the active fraction responding in the Biolog assay was adversely affected, suggesting a reduction in the functional potential. c2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.

Evaluation of phytotoxicity effect of olive mill wastewater treated by different technologies on seed germination of barley (Hordeum vulgare L.).

PubMed

Rusan, Munir J M; Albalasmeh, Ammar A; Zuraiqi, Said; Bashabsheh, Mohammad

2015-06-01

Olive-mill wastewater (OMW) is a by-product effluent of olive oil extraction process that is produced in large amount in the Mediterranean region. OMW is believed to induce phytotoxic effect on organisms including seed germination and plant growth. The objective of this study was to evaluate the impact of untreated and treated OMW with different techniques on seed germination of barley (Hordeum vulgare L.). The following treatments were investigated: (1) tap water (control); (2) OMW treated by aerobic biological technology in a Jacto Reactor (JR); (3) OMW treated by solar fenton oxidation (SFO); (4) OMW treated by microfiltration followed by nanofiltration (MF+NF); (5) OMW treated by microfiltration followed by reverse osmosis (MF+RO) process; (6) diluted OMW with tap water (25 % OMW); (7) diluted OMW with tap water (50 % OMW); (8) diluted OMW with tap water (75 % OMW); and (9) untreated OMW (100 % OMW). A germination test was conducted in an incubator at temperature of 23 (∘)C. In each petri dish, a filter paper was mounted and ten seeds of barley were placed on the filter paper. Five milliliter of water were added to each petri dish. The seed germination was determined by counting the number of germinated seeds to calculate the percentage of germination (G %). Germination rate index (GRI), seed vigor index (SVI), and phytotoxicity index (PI) were also calculated. Then, the dry weights and lengths of the shoots and the roots of the germinated seeds were measured. The results show that 100, 75, and 50 %OMW were very phytotoxic and completely prohibited seed germination. However, phytotoxicity decreased significantly following treatments of OMW with all techniques investigated and by the 25 % OMW dilution, as results of removing the phenols and other phytotoxic organic compounds from the OMW or by diluting it. This was evidenced by relative enhancement of the dry weights and lengths of shoot and root as well as the G %, GRI, SVG, and PI. It was concluded that if OMW will be used for irrigating crops, it has to be first treated or diluted with tap water at a ratio of 1:3 OMW:water at least. The most efficient treatment techniques in reducing the phytotoxicity of OMW were the MF+RO, followed by SFO and JR.

ABO grouping of highly-dilute blood by the absorption-elution technique using nitrocellulose beads--application to a casework investigation.

PubMed

Fujitani, N; Matoba, R; Kobayashi, T; Matsuda, H; Yoshida, K; Fukita, K

1991-04-01

This paper reports a homicidal case in which the absorption-elution technique using nitrocellulose beads as immunoadsorbents was successfully applied to ABO grouping from highly-diluted blood. A 21-year-old man was found dead in bed while staying in a hotel. He had multiple wounds over the entire body. By autopsy the cause of death was decided to be traumatic shock. The victim's blood group was A. A bucket filled with faint-colored water was found at the scene. By means of the absorption-elution technique using nitrocellulose beads the water was grouped as B. Later, a 32-year-old man staying in the hotel together with the victim was suspected and arrested. The suspect's blood group was B. He confessed that he had injured himself in the hands with a knife during the struggle and washed them in the water.

Analysis of peptides using an integrated microchip HPLC-MS/MS system.

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

Kirby, Brian J.; Chirica, Gabriela S.; Reichmuth, David S.

Hyphendated LC-MS techniques are quickly becoming the standard tool for protemic analyses. For large homogeneous samples, bulk processing methods and capillary injection and separation techniques are suitable. However, for analysis of small or heterogeneous samples, techniques that can manipulate picoliter samples without dilution are required or samples will be lost or corrupted; further, static nanospray-type flowrates are required to maximize SNR. Microchip-level integration of sample injection with separation and mass spectrometry allow small-volume analytes to be processed on chip and immediately injected without dilution for analysis. An on-chip HPLC was fabricated using in situ polymerization of both fixed and mobilemore » polymer monoliths. Integration of the chip with a nanospray MS emitter enables identification of peptides by the use of tandem MS. The chip is capable of analyzing of very small sample volumes (< 200 pl) in short times (< 3 min).« less

Measurement of lung volumes from supine portable chest radiographs.

PubMed

Ries, A L; Clausen, J L; Friedman, P J

1979-12-01

Lung volumes in supine nonambulatory patients are physiological parameters often difficult to measure with current techniques (plethysmograph, gas dilution). Existing radiographic methods for measuring lung volumes require standard upright chest radiographs. Accordingly, in 31 normal supine adults, we determined helium-dilution functional residual and total lung capacities and measured planimetric lung field areas (LFA) from corresponding portable anteroposterior and lateral radiographs. Low radiation dose methods, which delivered less than 10% of that from standard portable X-ray technique, were utilized. Correlation between lung volume and radiographic LFA was highly significant (r = 0.96, SEE = 10.6%). Multiple-step regressions using height and chest diameter correction factors reduced variance, but weight and radiographic magnification factors did not. In 17 additional subjects studied for validation, the regression equations accurately predicted radiographic lung volume. Thus, this technique can provide accurate and rapid measurement of lung volume in studies involving supine patients.

Work Program. Fiscal Year 1969 for The Department of the Army. Research and Development in Training, Motivation, and Leadership

DTIC Science & Technology

1969-01-01

job requiremeits in these skills , and (2) developing technique.; for improving literacy skills through training. In addition, manpower pools for a given...job requirements in these skills , and (2) developing techniques for improving literacy skills through training. In addition, manpower pools for a...visual and psychomotor skills -for accurate .nd’efficient operation, and performance variations among gunners are the largest source of error in system

Computer Simulation of the Population Growth (Schizosaccharomyces Pombe) Experiment.

ERIC Educational Resources Information Center

Daley, Michael; Hillier, Douglas

1981-01-01

Describes a computer program (available from authors) developed to simulate "Growth of a Population (Yeast) Experiment." Students actively revise the counting techniques with realistically simulated haemocytometer or eye-piece grid and are reminded of the necessary dilution technique. Program can be modified to introduce such variables…

Picosecond coherent anti-Stokes Raman scattering (CARS) study of vibrational dephasing of carbon disulfide and benzene in solution

NASA Technical Reports Server (NTRS)

Perry, Joseph W.; Woodward, Anne M.; Stephenson, John C.

1986-01-01

The vibrational dephasing of the 656/cm mode (nu1, a1g) of CS2 and the 991/cm mode (nu2, a1g) of benzene have been studied as a function of concentration in mixtures with a number of solvents using a ps time-resolved CARS technique. This technique employs two tunable synchronously-pumped mode-locked dye lasers in a stimulated Raman pump, coherent anti-Stokes Raman probe time-resolved experiment. Results are obtained for CS2 in carbon tetrachloride, benzene, nitrobenzene, and ethanol and for benzene nu2 in CS2. The dephasing rates of CS2 nu1 increase on dilution with the polar solvents and decrease or remain constant on dilution with the nonpolar solvents. The CS2/benzene solutions show a contrasting behavior, with the CS2 nu1 dephasing rate being nearly independent of concentration whereas the benzene nu2 dephasing rate decreases on dilution. These results are compared to theoretical models for vibrational dephasing of polyatomic molecules in solution.

Comparison of an automated Most Probable Number (MPN) technique to traditional plating methods for estimating populations of total aerobes, coliforms and E. coli associated with freshly processed broiler chickens

USDA-ARS?s Scientific Manuscript database

Traditional microbiological techniques for estimating populations of viable bacteria can be laborious and time consuming. The Most Probable Number (MPN) technique is especially tedious as multiple series of tubes must be inoculated at several different dilutions. Recently, an instrument (TEMPOTM) ...

Multiple sulfur isotopes fractionations associated with abiotic sulfur transformations in Yellowstone National Park geothermal springs

PubMed Central

2014-01-01

Background The paper presents a quantification of main (hydrogen sulfide and sulfate), as well as of intermediate sulfur species (zero-valent sulfur (ZVS), thiosulfate, sulfite, thiocyanate) in the Yellowstone National Park (YNP) hydrothermal springs and pools. We combined these measurements with the measurements of quadruple sulfur isotope composition of sulfate, hydrogen sulfide and zero-valent sulfur. The main goal of this research is to understand multiple sulfur isotope fractionation in the system, which is dominated by complex, mostly abiotic, sulfur cycling. Results Water samples from six springs and pools in the Yellowstone National Park were characterized by pH, chloride to sulfate ratios, sulfide and intermediate sulfur species concentrations. Concentrations of sulfate in pools indicate either oxidation of sulfide by mixing of deep parent water with shallow oxic water, or surface oxidation of sulfide with atmospheric oxygen. Thiosulfate concentrations are low (<6 μmol L-1) in the pools with low pH due to fast disproportionation of thiosulfate. In the pools with higher pH, the concentration of thiosulfate varies, depending on different geochemical pathways of thiosulfate formation. The δ34S values of sulfate in four systems were close to those calculated using a mixing line of the model based on dilution and boiling of a deep hot parent water body. In two pools δ34S values of sulfate varied significantly from the values calculated from this model. Sulfur isotope fractionation between ZVS and hydrogen sulfide was close to zero at pH < 4. At higher pH zero-valent sulfur is slightly heavier than hydrogen sulfide due to equilibration in the rhombic sulfur–polysulfide – hydrogen sulfide system. Triple sulfur isotope (32S, 33S, 34S) fractionation patterns in waters of hydrothermal pools are more consistent with redox processes involving intermediate sulfur species than with bacterial sulfate reduction. Small but resolved differences in ∆33S among species and between pools are observed. Conclusions The variation of sulfate isotopic composition, the origin of differences in isotopic composition of sulfide and zero–valent sulfur, as well as differences in ∆33S of sulfide and sulfate are likely due to a complex network of abiotic redox reactions, including disproportionation pathways. PMID:24959098

Algicidal and Sanitizing Properties of Armazide1

PubMed Central

Antonides, H. J.; Tanner, W. S.

1961-01-01

Algicidal and sanitizing properties of Armazide, a new swimming pool additive, consisting of 12% w/v each of dodecylamine hydrochloride, trimethyl alkyl ammonium chloride, and methyl alkyl dipolyoxypropylene ammonium methyl sulfate in solution, were evaluated by laboratory techniques against algae and sewage. Results indicated it to be highly effective in low concentrations especially in conjunction with low concentrations of chlorine. Swimming pool field tests were found to confirm the laboratory findings. Various treatment levels and methods are described for swimming pools using treatments based upon the actual condition of the pool and water. The use of the product permitted a reduction in chlorine residual in pools resulting in greatly reduced requirements for chlorinating chemicals along with absence of irritation, odor, and other undesirable results usually associated with standard pool chlorination methods. PMID:13861802

Accuracy of two osmometers on standard samples: electrical impedance technique and freezing point depression technique

NASA Astrophysics Data System (ADS)

García-Resúa, Carlos; Pena-Verdeal, Hugo; Miñones, Mercedes; Gilino, Jorge; Giraldez, Maria J.; Yebra-Pimentel, Eva

2013-11-01

High tear fluid osmolarity is a feature common to all types of dry eye. This study was designed to establish the accuracy of two osmometers, a freezing point depression osmometer (Fiske 110) and an electrical impedance osmometer (TearLab™) by using standard samples. To assess the accuracy of the measurements provided by the two instruments we used 5 solutions of known osmolarity/osmolality; 50, 290 and 850 mOsm/kg and 292 and 338 mOsm/L. Fiske 110 is designed to be used in samples of 20 μl, so measurements were made on 1:9, 1:4, 1:1 and 1:0 dilutions of the standards. Tear Lab is addressed to be used in tear film and only a sample of 0.05 μl is required, so no dilutions were employed. Due to the smaller measurement range of the TearLab, the 50 and 850 mOsm/kg standards were not included. 20 measurements per standard sample were used and differences with the reference value was analysed by one sample t-test. Fiske 110 showed that osmolarity measurements differed statistically from standard values except those recorded for 290 mOsm/kg standard diluted 1:1 (p = 0.309), the 292 mOsm/L H2O sample (1:1) and 338 mOsm/L H2O standard (1:4). The more diluted the sample, the higher the error rate. For the TearLab measurements, one-sample t-test indicated that all determinations differed from the theoretical values (p = 0.001), though differences were always small. For undiluted solutions, Fiske 110 shows similar performance than TearLab. However, for the diluted standards, Fiske 110 worsens.

Detection of fecal residue on poultry carcasses by laser induced fluorescence imaging techniques

USDA-ARS?s Scientific Manuscript database

The potential use of laser-induced fluorescence imaging techniques was investigated for the detection of diluted fecal matters from various parts of the digestive tract, including colon, ceca, small intestine, and duodenum, on poultry carcasses. One of the challenges for using fluorescence imaging f...

In situ formation of phosphate barriers in soil

DOEpatents

Moore, Robert C.

2002-01-01

Reactive barriers and methods for making reactive barriers in situ in soil for sequestering soil ontaminants including actinides and heavy metals. The barrier includes phosphate, and techniques are disclosed for forming specifically apatite barriers. The method includes injecting dilute reagents into soil in proximity to a contamination plume or source such as a waste drum to achieve complete or partial encapsulation of the waste. Controlled temperature and pH facilitates rapid formation of apatite, for example, where dilute aqueous calcium chloride and dilute aqueous sodium phosphate are the selected reagents. Mixing of reagents to form precipitate is mediated and enhanced through movement of reagents in soil as a result of phenomena including capillary action, movement of groundwater, soil washing and reagent injection pressure.

Reactivity of Pleistocene aged organic matter in the Siberian Arctic

NASA Astrophysics Data System (ADS)

Davydov, S.; Vonk, J. E.; Mann, P. J.; Davydova, A.; Sobczak, W. V.; Schade, J. D.; Bulygina, E. B.; Zimov, S. A.; Holmes, R. M.

2011-12-01

Half of the global stock of soil organic carbon (OC) is stored in Arctic permafrost. About one third of this pool consists of so-called yedoma, organic-rich deposits that were formed during the Pleistocene. Previous studies show rapid respiration of yedoma upon thawing, with the potential release of large quantities of relict OC into the contemporary C cycle. The fluvial and coastal reactivity of this OC, however, and its fate remain unclear. Duvannyi Yar is a well-studied yedoma exposure on the banks of Kolyma River in Northeastern Siberia. It can serve as a model for the >7000 km long East Siberian Arctic coastline that is dominated by similarly exposed yedoma cliffs, and is increasingly vulnerable to erosion with climate warming-induced decreases in sea-ice, and increases in storms and wave-fetch. Permafrost thaw causes the slopes of Duvannyi Yar to retreat 3-5 m/y, producing mudstreams that drain into the Kolyma River. These streams are heavily loaded with freshly thawed yedoma sediments (ca. 650 g/L; POC ca. 10 g/L; DOC ca. 150 mg/L). Partial CO2 pressure in these streams was on average 8400 ppm (stdev 2100; n=4) whereas the Kolyma River at the stream mouth contained CO2 concentrations of ca. 900 ppm (stdev 90; n=4), suggesting substantial outgassing during transport. We performed biological oxygen demand assays in combination with a set of incubations to estimate OC lability in a range of dilutions of Duvannyi Yar water with Kolyma River and East Siberian Sea water, in combination with nutrient and enzymatic activity rate analysis to identify potential limitation processes. Our goal was to assess carbon consumption rates and the effect of different microbial communities along its transport towards the ocean. O2 loss (% after 24h) increased significantly from undiluted Kolyma water to increasingly spiked dilutions with filtered Duvannyi Yar filtered water; 0%/0.5%/1%/10%/100% dilutions showed O2 losses of 1.6%, 3.5%, 5.1%, 13% and 35%, respectively. However, C-normalized O2 losses demonstrated a different pattern. After a 24h C-loss of 5-7% for all three dilutions, the 10% dilution continued to respond up to a total of 33% lost carbon after 5 days. Enzymatic activity rates of the lignin-degrading enzyme phenoloxidase corroborated this by showing strongly elevated activity rates for the 10% Duvannyi Yar-Kolyma dilution, opposite to the 1% or 0.5% dilutions or Kolyma background. Dilutions with Kolyma water showed a slightly but consistently higher processing rate compared to dilutions of East Siberian Sea water (26 salinity). These results suggest that old OC is biologically labile upon fluvial release and its breakdown appears to be limited by availability of organic substrates. Furthermore, it appears that refractory carbon in the Kolyma is in fact being processed faster when enough Duvannyi Yar water, along with its microbes and enzymes, is added.

Level of Neutral Buoyancy, Deep Convective Outflow, and Hot Tower: New Perspectives Based on the A-Train Observations

NASA Astrophysics Data System (ADS)

Takahashi, H.; Luo, J.; Stephens, G. L.

2016-12-01

Deep convective cores, or "hot towers (HTs)", play a significant role in controlling the energy budgets and hydrological cycles. The vertical convective transport by HTs is like an express elevator transporting the near-surface air directly into the upper troposphere or lower stratosphere (e.g., Riehl and Malkus, 1958; Sun and Lindzen, 1993; Soden and Fu, 1995). The vertical convective transport will eventually make a transition to horizontal outflows where widespread cirrus anvils develop, which also play an important role in radiative-convective feedbacks (e.g., Stephens et al. 2008). In this study, we introduce two proxies to evaluate the strength of vertical and horizontal convective mass transport by hot towers. Result shows that HTs tend to have wider horizontal mass transport over land than ocean. In addition, an important aspect of the deep convection-to-outflow transition is the altitude where the outflow occurs, which can be conveniently summarized into a single parameter called level of neutral buoyancy (LNB). LNB is a critical parameter for understanding convection because it sets the potential vertical extent for convective development. This study develops a deeper and more comprehensive understanding of the relationship between LNB and deep convective outflow, including regional variations. To this end, a useful proxy to estimate convective dilution is introduced. Results show that active convective dilution can be seen over the Warm Pool throughout the year, while deep convection over tropical Africa and Amazonia tends to be less diluted.

Simultaneous detection of six urinary pteridines and creatinine by high-performance liquid chromatography-tandem mass spectrometry for clinical breast cancer detection.

PubMed

Burton, Casey; Shi, Honglan; Ma, Yinfa

2013-11-19

Recent preliminary studies have implicated urinary pteridines as candidate biomarkers in a growing number of malignancies including breast cancer. While the developments of capillary electrophoresis-laser induced fluorescence (CE-LIF), high performance liquid chromatography (HPLC), and liquid chromatography-mass spectroscopy (LC-MS) pteridine urinalyses among others have helped to enable these findings, limitations including poor pteridine specificity, asynchronous or nonexistent renal dilution normalization, and a lack of information regarding adduct formation in mass spectrometry techniques utilizing electrospray ionization (ESI) have prevented application of these techniques to a larger clinical setting. In this study, a simple, rapid, specific, and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method has been developed and optimized for simultaneous detection of six pteridines previously implicated in breast cancer and creatinine as a renal dilution factor in urine. In addition, this study reports cationic adduct formation of urinary pteridines under ESI-positive ionization for the first time. This newly developed technique separates and detects the following six urinary pteridines: 6-biopterin, 6-hydroxymethylpterin, d-neopterin, pterin, isoxanthopterin, and xanthopterin, as well as creatinine. The method detection limit for the pteridines is between 0.025 and 0.5 μg/L, and for creatinine, it is 0.15 μg/L. The method was also validated by spiked recoveries (81-105%), reproducibility (RSD: 1-6%), and application to 25 real urine samples from breast cancer positive and negative samples through a double-blind study. The proposed technique was finally compared directly with a previously reported CE-LIF technique, concluding that additional or alternative renal dilution factors are needed for proper investigation of urinary pteridines as breast cancer biomarkers.

Minimizing inhibition of PCR-STR typing using digital agarose droplet microfluidics.

PubMed

Geng, Tao; Mathies, Richard A

2015-01-01

The presence of PCR inhibitors in forensic and other biological samples reduces the amplification efficiency, sometimes resulting in complete PCR failure. Here we demonstrate a high-performance digital agarose droplet microfluidics technique for single-cell and single-molecule forensic short tandem repeat (STR) typing of samples contaminated with high concentrations of PCR inhibitors. In our multifaceted strategy, the mitigation of inhibitory effects is achieved by the efficient removal of inhibitors from the porous agarose microgel droplets carrying the DNA template through washing and by the significant dilution of targets and remaining inhibitors to the stochastic limit within the ultralow nL volume droplet reactors. Compared to conventional tube-based bulk PCR, our technique shows enhanced (20 ×, 10 ×, and 16 ×) tolerance of urea, tannic acid, and humic acid, respectively, in STR typing of GM09948 human lymphoid cells. STR profiling of single cells is not affected by small soluble molecules like urea and tannic acid because of their effective elimination from the agarose droplets; however, higher molecular weight humic acid still partially inhibits single-cell PCR when the concentration is higher than 200 ng/μL. Nevertheless, the full STR profile of 9948 male genomic DNA contaminated with 500 ng/μL humic acid was generated by pooling and amplifying beads carrying single-molecule 9948 DNA PCR products in a single secondary reaction. This superior performance suggests that our digital agarose droplet microfluidics technology is a promising approach for analyzing low-abundance DNA targets in the presence of inhibitors. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Dispersion of nanosized ceramic powders in aqueous suspensions

NASA Astrophysics Data System (ADS)

Chera, L.; Palcevskis, E.; Berzins, M.; Lipe, A.; Jansone, I.

2007-12-01

Seven commercially available dispersants have been applied to produce high concentrated aqueous suspensions of the nanosized alumina and partially stabilized zirconia powders processed by the plasma technique. Simultaneously, the electrokinetic behaviour of powders has been investigated in diluted suspensions by microelectrophoresis method. Zeta potential measurements are used to estimate the influence of selected dispersants on the electrokinetic properties of the powder surface. On the basis of obtained data the correlation between the surface electrokinetic properties in dilute suspensions and reached maximal suspension concentration is discussed.

Bound Pool Fractions Complement Diffusion Measures to Describe White Matter Micro and Macrostructure

PubMed Central

Stikov, Nikola; Perry, Lee M.; Mezer, Aviv; Rykhlevskaia, Elena; Wandell, Brian A.; Pauly, John M.; Dougherty, Robert F.

2010-01-01

Diffusion imaging and bound pool fraction (BPF) mapping are two quantitative magnetic resonance imaging techniques that measure microstructural features of the white matter of the brain. Diffusion imaging provides a quantitative measure of the diffusivity of water in tissue. BPF mapping is a quantitative magnetization transfer (qMT) technique that estimates the proportion of exchanging protons bound to macromolecules, such as those found in myelin, and is thus a more direct measure of myelin content than diffusion. In this work, we combine BPF estimates of macromolecular content with measurements of diffusivity within human white matter tracts. Within the white matter, the correlation between BPFs and diffusivity measures such as fractional anisotropy and radial diffusivity was modest, suggesting that diffusion tensor imaging and bound pool fractions are complementary techniques. We found that several major tracts have high BPF, suggesting a higher density of myelin in these tracts. We interpret these results in the context of a quantitative tissue model. PMID:20828622

The influence of cockchafer larvae on net soil methane fluxes under different vegetation types - a mesocosm study

NASA Astrophysics Data System (ADS)

Görres, Carolyn-Monika; Kammann, Claudia; Chesmore, David; Müller, Christoph

2017-04-01

The influence of land-use associated pest insects on net soil CH4 fluxes has received little attention thus far, although e.g. soil-dwelling Scarabaeidae larvae are qualitatively known to emit CH4. The project "CH4ScarabDetect" aims to provide the first quantitative estimate of the importance of soil-dwelling larvae of two important European agricultural and forest pest insect species - the common cockchafer (Melolontha melolontha) and the forest cockchafer (M. hippocastani) - for net soil CH4 fluxes. Here we present a mesocosm study within "CH4ScarabDetect" which tests the influence of different abundances of common cockchafer larvae on net soil CH4 fluxes under different vegetation types. In August 2016, 27 PVC boxes with a base area of 50 cm x 50 cm and a height of 40 cm were buried in planting beds previously used for cultivating vegetables. The bottom of each box was filled with a 10 cm thick layer of loam which was then covered with a 25 cm thick layer of loamy sand. The soil was hand-sieved prior to filling the boxes to remove any macrofauna. The mesocosms were planted with either turf, carrots or a combination of both. Of the resulting nine replicates per vegetation type, six were infested with one cockchafer larvae each in November 2016. In three of these infested mesocosms, the larvae abundance will be further increased to three in May 2017. This mesocosm study will continue until October 2017 during which measurements of net soil CH4 fluxes will be conducted with the chamber flux method twice per month. For the in situ separation of gross CH4 production and gross CH4 oxidation, the chamber method will be combined with a 13CH4 isotope pool dilution technique. Methane concentrations and their isotopic signatures in the collected gas samples will be analysed with a state-of-the-art CRDS analyzer (cavity ring-down spectroscopy, G2201-i) equipped with the Small Sample Isotope Module 2 - A0314 (Picarro Inc., USA). Different combinations of larvae abundance and depth distribution might yield the same net CH4 flux rates. To account for this non-invasively, the chamber measurements are additionally combined with acoustic measurements of larvae activity in the soil. For this purpose, an acoustice sensor is installed in the middle of each mesocom. This is the first time that a 13CH4 isotope pool dilution technique, the chamber method, and acoustic measurements are combined to study non-invasively the influence of soil-dwelling larve on net soil CH4 fluxes in the field. This novel approach will not only further our understanding of the role of cockchafer larvae in the terrestrial CH4 cycle and provide a new tool for soil CH4 flux and soil insect studies, but promises to also improve our knowledge on cockchafer ecology as well as the monitoring of cockchafer infestations in agricultural and forest soils. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 703107.

Concentrations of phthalates and DINCH metabolites in pooled urine from Queensland, Australia.

PubMed

Gomez Ramos, M J; Heffernan, A L; Toms, L M L; Calafat, A M; Ye, X; Hobson, P; Broomhall, S; Mueller, J F

2016-03-01

Dialkyl phthalate esters (phthalates) are ubiquitous chemicals used extensively as plasticizers, solvents and adhesives in a range of industrial and consumer products. 1,2-Cyclohexane dicarboxylic acid, diisononyl ester (DINCH) is a phthalate alternative introduced due to a more favourable toxicological profile, but exposure is largely uncharacterised. The aim of this study was to provide the first assessment of exposure to phthalates and DINCH in the general Australian population. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n=24 pools of 100). Concentrations of free and total species were measured using online solid phase extraction isotope dilution high performance liquid chromatography tandem mass spectrometry. Concentrations ranged from 2.4 to 71.9ng/mL for metabolites of di(2-ethylhexyl)phthalate, and from <0.5 to 775ng/mL for all other metabolites. Our data suggest that phthalate metabolites concentrations in Australia were at least two times higher than in the United States and Germany; and may be related to legislative differences among countries. DINCH metabolite concentrations were comparatively low and consistent with the limited data available. Ongoing biomonitoring among the general Australian population may help assess temporal trends in exposure and assess the effectiveness of actions aimed at reducing exposures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Control of Gas Tungsten Arc welding pool shape by trace element addition to the weld pool

DOEpatents

Heiple, C.R.; Burgardt, P.

1984-03-13

An improved process for Gas Tungsten Arc welding maximizes the depth/width ratio of the weld pool by adding a sufficient amount of a surface active element to insure inward fluid flow, resulting in deep, narrow welds. The process is especially useful to eliminate variable weld penetration and shape in GTA welding of steels and stainless steels, particularly by using a sulfur-doped weld wire in a cold wire feed technique.

Detection of Toxoplasma oocysts from soil by modified sucrose flotation and PCR methods.

PubMed

Matsuo, Junji; Kimura, Daisuke; Rai, Shiba Kumar; Uga, Shoji

2004-06-01

A detection method of Toxoplasma gondii oocysts from soil was evaluated using the sucrose flotation technique with modification involving addition of 0.1% gelatin into washing and floating solutions. PCR was performed on untreated samples and after treatment with polyvinylpyrrolidone (PVP), heating and cooling, and NaCl. The addition of gelatin in the sucrose solution yielded a higher number of oocysts. A very thin band was observed when DNA extract was diluted to 1:1024, indicating the presence of PCR inhibitor in the soil. PCR performed on untreated DNA, on PVP-treated, and on PVP-treated with heating and cooling without added bovine serum albumin (BSA) showed a band only at higher dilutions (1:1024 and 1:512) but at a much lower dilution (1:8) with BSA. In contrast, DNA treated with all three agents showed a band at a much lower dilution (1:64), even without added BSA, and no dilution was required when BSA was added. The PCR inhibitors present in the soil were removed by employing various treatment procedures during DNA extraction, and BSA in PCR. Furthermore, the detection limit with the method was 1 oocyst/g of soil, indicating that this method is useful in epidemiological studies.

An investigation of flame spread over shallow liquid pools in microgravity and nonair environments

NASA Technical Reports Server (NTRS)

Ross, Howard D.; Sotos, Raymond G.

1991-01-01

Experiments of interest to combustion fundamentals and spacecraft fire safety investigated flame spread of alcohol fuels over shallow, 15 cm diameter pools in a 5.2 sec free-fall, microgravity facility. Results showed that, independent O2 concentrations, alcohol fuel, and diluent types, microgravity flame spread rates were nearly identical to those corresponding normal-gravity flames for conditions where the normal gravity flames spread uniformly. This similarity indicated buoyancy-related convection in either phase does not affect flame spread, at least for the physical scale of the experiments. However, microgravity extinction coincided with the onset conditions for pulsating spread in normal gravity, implicating gas phase, buoyant flow as a requirement for pulsating spread. When the atmospheric nitrogen was replaced with argon, the conditions for the onset of normal-gravity pulsating flame spread and microgravity flame extinction were changed, in agreement with the expected lowering of the flash point through the thermal properties of the diluent. Helium-diluted flames, however, showed unexpected results with a shift to apparently higher flash-point temperatures and high normal gravity pulsation amplitudes.

An Investigation of Flame Spread over Shallow Liquid Pools in Microgravity and Nonair Environments

NASA Technical Reports Server (NTRS)

Ross, Howard D.; Sotos, Raymond G.

1989-01-01

Experiments of interest to combustion fundamentals and spacecraft fire safety investigated flame spread of alcohol fuels over shallow, 15 cm diameter pools in a 5.2 sec free-fall, microgravity facility. Results showed that, independent O2 concentration, alcohol fuel, and diluent types, microgravity flame spread rates were nearly identical to those corresponding normal-gravity flames for conditions where the normal gravity flames spread uniformly. This similarity indicated buoyancy-related convection in either phase does not affect flame spread, at least for the physical scale of the experiments. However, microgravity extinction coincided with the onset conditions for pulsating spread in normal gravity, implicating gas phase, buoyant flow as a requirement for pulsating spread. When the atmospheric nitrogen was replaced with argon, the conditions for the onset of normal-gravity pulsating flame spread and microgravity flame extinction were changed, in agreement with the expected lowering of the flash point through the thermal properties of the diluent. Helium-diluted flames, however, showed unexpected results with a shift to apparently higher flash-point temperatures and high normal gravity pulsation amplitudes.

Two techniques for eliminating luminol interference material and flow system configurations for luminol and firefly luciferase systems

NASA Technical Reports Server (NTRS)

Thomas, R. R.

1976-01-01

Two methods for eliminating luminol interference materials are described. One method eliminates interference from organic material by pre-reacting a sample with dilute hydrogen peroxide. The reaction rate resolution method for eliminating inorganic forms of interference is also described. The combination of the two methods makes the luminol system more specific for bacteria. Flow system designs for both the firefly luciferase and luminol bacteria detection systems are described. The firefly luciferase flow system incorporating nitric acid extraction and optimal dilutions has a functional sensitivity of 3 x 100,000 E. coli/ml. The luminol flow system incorporates the hydrogen peroxide pretreatment and the reaction rate resolution techniques for eliminating interference. The functional sensitivity of the luminol flow system is 1 x 10,000 E. coli/ml.

Adaptation of the Sensititre broth microdilution technique to antimicrobial susceptibility testing of Mycoplasma hyopneumoniae.

PubMed

Tanner, A C; Erickson, B Z; Ross, R F

1993-09-01

A broth microdilution technique is described for determining the antimicrobial susceptibility of Mycoplasma hyopneumoniae, using commercially prepared Sensititre plates. Twenty-five field isolates and two reference strains (J & 232), were tested against seven antimicrobials. Field isolates were tested in duplicate and reference strains, four times to estimate reproducibility. Ninety-seven percent of the duplicate MIC results for the field isolates were in agreement, or within one log2 dilution. Similar results were obtained with the reference strains. The isolates were susceptible to lincomycin-spectinomycin, tylosin and oxytetracycline or resistant to amoxycillin, apramycin and erythromycin. Susceptibility to furaltadone varied. This method retains the accuracy and reproducibility of broth MIC determinations, while avoiding the lengthy preparation of antimicrobial dilutions normally associated with more traditional methods.

A comparison study of Co and Cu doped MgO diluted magnetic thin films

NASA Astrophysics Data System (ADS)

Sarıtaş, S.; ćakıcı, T.; Muǧlu, G. Merhan; Kundakcı, M.; Yıldırım, M.

2017-02-01

Transition metal-doped MgO diluted magnetic thin films are appropriate candidates for spintronic applications and designing magnetic devices and sensors. Therefore, MgO:Co and MgO:Cu films were deposited on glass substrates by Chemical Spray Pyrolysis (CSP) method different thin film deposition parameters. Deposited different transition metal doped MgO thin films were compared in terms of optic and structural properties. Comparison optic analysis of the films was investigated spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. Comparison structural analysis of the thin films was examined by using XRD, Raman Analysis, SEM, EDX and AFM techniques. The transition metal-doped; MgO:Co and MgO:Cu thin films maybe have potential applications in spintronics and magnetic data storage.

Actual and simulated injury of Creontiades signatus (Heteroptera: Miridae) feeding on cotton bolls

USDA-ARS?s Scientific Manuscript database

The actual feeding injury of Creontiades signatus (Distant) was compared to a simulated technique for study years 2005, 2006 and 2008 by injecting varying dilutions of pectinase into cotton bolls at different boll sizes (ages) in an effort to determine if such a technique could be used to reduce the...

Imaging soil litter decomposition: Integrating sychrotron-based elemental and molecular imaging techniques

EPA Science Inventory

Forest ecosystems contain approximately one-half of the Earths terrestrial carbon (C) (1146 Pg), with two-thirds (787 Pg) of this pool residing in forest soils. Given the magnitude of the forest soil C pool, it is critical to understand the mechanisms that control soil organic ma...

Characterization of carrier erythrocytes for biosensing applications

NASA Astrophysics Data System (ADS)

Bustamante López, Sandra C.; Meissner, Kenith E.

2017-09-01

Erythrocyte abundance, mobility, and carrying capacity make them attractive as a platform for blood analyte sensing as well as for drug delivery. Sensor-loaded erythrocytes, dubbed erythrosensors, could be reinfused into the bloodstream, excited noninvasively through the skin, and used to provide measurement of analyte levels in the bloodstream. Several techniques to load erythrocytes, thus creating carrier erythrocytes, exist. However, their cellular characteristics remain largely unstudied. Changes in cellular characteristics lead to removal from the bloodstream. We hypothesize that erythrosensors need to maintain native erythrocytes' (NEs) characteristics to serve as a long-term sensing platform. Here, we investigate two loading techniques and the properties of the resulting erythrosensors. For loading, hypotonic dilution requires a hypotonic solution while electroporation relies on electrical pulses to perforate the erythrocyte membrane. We analyze the resulting erythrosensor signal, size, morphology, and hemoglobin content. Although the resulting erythrosensors exhibit morphological changes, their size was comparable with NEs. The hypotonic dilution technique was found to load erythrosensors much more efficiently than electroporation, and the sensors were loaded throughout the volume of the erythrosensors. Finally, both techniques resulted in significant loss of hemoglobin. This study points to the need for continued development of loading techniques that better preserve NE characteristics.

Pooling sheep faecal samples for the assessment of anthelmintic drug efficacy using McMaster and Mini-FLOTAC in gastrointestinal strongyle and Nematodirus infection.

PubMed

Kenyon, Fiona; Rinaldi, Laura; McBean, Dave; Pepe, Paola; Bosco, Antonio; Melville, Lynsey; Devin, Leigh; Mitchell, Gillian; Ianniello, Davide; Charlier, Johannes; Vercruysse, Jozef; Cringoli, Giuseppe; Levecke, Bruno

2016-07-30

In small ruminants, faecal egg counts (FECs) and reduction in FECs (FECR) are the most common methods for the assessment of intensity of gastrointestinal (GI) nematodes infections and anthelmintic drug efficacy, respectively. The main limitation of these methods is the time and cost to conduct FECs on a representative number of individual animals. A cost-saving alternative would be to examine pooled faecal samples, however little is known regarding whether pooling can give representative results. In the present study, we compared the FECR results obtained by both an individual and a pooled examination strategy across different pool sizes and analytical sensitivity of the FEC techniques. A survey was conducted on 5 sheep farms in Scotland, where anthelmintic resistance is known to be widespread. Lambs were treated with fenbendazole (4 groups), levamisole (3 groups), ivermectin (3 groups) or moxidectin (1 group). For each group, individual faecal samples were collected from 20 animals, at baseline (D0) and 14 days after (D14) anthelmintic administration. Faecal samples were analyzed as pools of 3-5, 6-10, and 14-20 individual samples. Both individual and pooled samples were screened for GI strongyle and Nematodirus eggs using two FEC techniques with three different levels of analytical sensitivity, including Mini-FLOTAC (analytical sensitivity of 10 eggs per gram of faeces (EPG)) and McMaster (analytical sensitivity of 15 or 50 EPG).For both Mini-FLOTAC and McMaster (analytical sensitivity of 15 EPG), there was a perfect agreement in classifying the efficacy of the anthelmintic as 'normal', 'doubtful' or 'reduced' regardless of pool size. When using the McMaster method (analytical sensitivity of 50 EPG) anthelmintic efficacy was often falsely classified as 'normal' or assessment was not possible due to zero FECs at D0, and this became more pronounced when the pool size increased. In conclusion, pooling ovine faecal samples holds promise as a cost-saving and efficient strategy for assessing GI nematode FECR. However, for the assessment FECR one will need to consider the baseline FEC, pool size and analytical sensitivity of the method. Copyright © 2016. Published by Elsevier B.V.

Quantitation of amyloid beta peptides Aβ(1-38), Aβ(1-40), and Aβ(1-42) in human cerebrospinal fluid by ultra-performance liquid chromatography-tandem mass spectrometry.

PubMed

Lame, Mary E; Chambers, Erin E; Blatnik, Matthew

2011-12-15

Critical events in Alzheimer's disease (AD) involve an imbalance between the production and clearance of amyloid beta (Aβ) peptides from the brain. Current methods for Aβ quantitation rely heavily on immuno-based techniques. However, these assays require highly specific antibodies and reagents that are time-consuming and expensive to develop. Immuno-based assays are also characterized by poor dynamic ranges, cross-reactivity, matrix interferences, and dilution linearity problems. In particular, noncommercial immunoassays are especially subject to high intra- and interassay variability because they are not subject to more stringent manufacturing controls. Combinations of these factors make immunoassays more labor-intensive and often challenging to validate in support of clinical studies. Here we describe a mixed-mode solid-phase extraction method and an ultra-performance liquid chromatography tandem mass spectrometry (SPE UPLC-MS/MS) assay for the simultaneous quantitation of Aβ(1-38), Aβ(1-40), and Aβ(1-42) from human cerebrospinal fluid (CSF). Negative ion versus positive ion species were compared using their corresponding multiple reaction monitoring (MRM) transitions, and negative ions were approximately 1.6-fold greater in intensity but lacked selectivity in matrix. The positive ion MRM assay was more than sufficient to quantify endogenous Aβ peptides. Aβ standards were prepared in artificial CSF containing 5% rat plasma, and quality control samples were prepared in three pooled CSF sources. Extraction efficiency was greater than 80% for all three peptides, and the coefficient of variation during analysis was less than 15% for all species. Mean basal levels of Aβ species from three CSF pools were 1.64, 2.17, and 1.26 ng/ml for Aβ(1-38); 3.24, 3.63, and 2.55 ng/ml for Aβ(1-40); and 0.50, 0.63, and 0.46 ng/ml for Aβ(1-42). Copyright © 2011 Elsevier Inc. All rights reserved.

Quantification of the degree of reaction of fly ash

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

Ben Haha, M., E-mail: mohsen.ben-haha@empa.c; De Weerdt, K., E-mail: klaartje.de.weerdt@sintef.n; Lothenbach, B.

2010-11-15

The quantification of the fly ash (FA) in FA blended cements is an important parameter to understand the effect of the fly ash on the hydration of OPC and on the microstructural development. The FA reaction in two different blended OPC-FA systems was studied using a selective dissolution technique based on EDTA/NaOH, diluted NaOH solution, the portlandite content and by backscattered electron image analysis. The amount of FA determined by selective dissolution using EDTA/NaOH is found to be associated with a significant possible error as different assumptions lead to large differences in the estimate of FA reacted. In addition, atmore » longer hydration times, the reaction of the FA is underestimated by this method due to the presence of non-dissolved hydrates and MgO rich particles. The dissolution of FA in diluted NaOH solution agreed during the first days well with the dissolution as observed by image analysis. At 28 days and longer, the formation of hydrates in the diluted solutions leads to an underestimation. Image analysis appears to give consistent results and to be most reliable technique studied.« less

Rapid and highly reproducible analysis of rare earth elements by multiple collector inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Baker, Joel; Waight, Tod; Ulfbeck, David

2002-10-01

A method has been developed for the rapid chemical separation and highly reproducible analysis of the rare earth elements (REE) by isotope dilution analysis by means of a multiple collector inductively coupled plasma mass spectrometer (MC-ICP-MS). This technique is superior in terms of the analytical reproducibility or rapidity of analysis compared with quadrupole ICP-MS or with thermal ionization mass spectrometric isotope dilution techniques. Samples are digested by standard hydrofluoric-nitric acid-based techniques and spiked with two mixed spikes. The bulk REE are separated from the sample on a cation exchange column, collecting the middle-heavy and light REE as two groups, which provides a middle-heavy REE cut with sufficient separation of the light from the heavier REE to render oxide interferences trivial, and a Ba-free light REE cut. The heavy (Er-Lu), middle (Eu-Gd), and light REE (La-Eu) concentrations are determined by three short (1 to 2 min) analyses with a CETAC Aridus desolvating nebulizer introduction system. Replicate digestions of international rock standards demonstrate that concentrations can be reproduced to <1%, which reflects weighing errors during digestion and aliquotting as inter-REE ratios reproduce to ≤0.2% (2 SD). Eu and Ce anomalies reproduce to <0.15%. In addition to determining the concentrations of polyisotopic REE by isotope dilution analysis, the concentration of monoisotopic Pr can be measured during the light REE isotope dilution run, by reference to Pr/Ce and Pr/Nd ratios measured in a REE standard solution. Pr concentrations determined in this way reproduce to <1%, and Pr/REE ratios reproduce to <0.4%. Ce anomalies calculated with La and Pr also reproduce to <0.15% (2 SD). The precise Ce (and Eu) anomaly measurements should allow greater use of these features in studying the recycling of materials with these anomalies into the mantle, or redox-induced effects on the REE during recycling and dehydration of oceanic lithosphere, partial melting, metamorphism, alteration, or sedimentation processes. Moreover, this technique consumes very small amounts (subnanograms) of the REE and will allow precise REE determinations to be made on much smaller samples than hitherto possible.

N-15 tracing helps explaining N leaching losses from contrasting forest ecosystems

NASA Astrophysics Data System (ADS)

Staelens, J.; Rütting, T.; Huygens, D.; Müller, C.; Verheyen, K.; Boeckx, P.

2009-04-01

Despite chronically enhanced nitrogen (N) deposition to forest ecosystems in Europe and NE America, considerable N retention by forests has been observed, reducing N leaching losses. Organic and mineral soil layers typically immobilize more N than the aboveground biomass, but it is unclear which factors determine N retention in forest ecoystems. However, this knowledge is crucial to assess the impact of changing anthropogenic N emissions on future N cycling and N loss of forests. For coniferous and deciduous forest stands at comparable sites, it is known that both N deposition onto the forest floor as well as N loss by leaching below the rooting zone are significantly higher in coniferous stands. In addition, the N loss in coniferous stands is often more enhanced than can be explained by the higher N input only. This suggests lower N retention by coniferous stands, and may be related to differences in litter and soil characteristics, microbial activity, and N uptake by plant roots. To test this hypothesis, we studied the effect of forest type on N retention using 15N tracing techniques: a field tracer experiment and a combination of in situ isotope pool dilution and a tracing model. The N dynamics were examined for two adjacent forest stands (pedunculate oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.)) on a well-drained sandy soil and with a similar stand history, located in a region with high N deposition (Belgium). Input-output N budgets were established by quantifying atmospheric deposition and leaching below the rooting zone, and confirmed the above finding of higher N deposition and disproportionately higher N loss for the pine stand compared to the oak stand. First, the fate of inorganic N within the ecosystems was studied by spraying three pulses of dissolved 15N, either as ammonium or as nitrate, onto the forest floor in 12 plots of 25 m2. The organic and mineral soil layers, tree roots, soil water percolate, ferns, and tree foliage were sampled and analyzed for total N and 15N four times in the year after 15N application. Here we present results of the 15N recovery four months after the first application, and compare the recovery between the two forest stands and the two N treatments. Second, gross N transformation rates in the undisturbed mineral forest soils were determined via 15N pool dilution and advanced trace modelling. Using five spatial replicates per stand, three 15N treatments were applied in the field to 'virtual' soil cores (0-10 cm) that were disturbed only at sampling. Each treatment solution contained ammonium, nitrate, and nitrite, with one of the N forms labelled with 15N at 99% at. excess. Intact soil cores were sampled at six time intervals over a 12-day period, and analyzed for N and 15N content in different mineral and organic pools. The parameters of different simultaneously occurring process rates were optimized using a Markov Chain Monte Carlo algorithm. In both stands, heterotrophic nitrification of the organic soil pool was more important than autotrophic nitrification of ammonium. Significantly different process rates between the two forest stands were found for mineralization, heterotrophic and autotrophic nitrification, and ammonium and nitrate immobilization. Gross mineralization and ammonium immobilization rates were higher in the oak soil than in the pine soil. Gross nitrate production, in contrast, was faster in the pine soil, while nitrate immobilization was slower. These different soil nitrate dynamics likely contribute to the observed higher nitrate leaching loss in the pine than oak stand. In addition to the faster nitrate immobilization in the oak soil, our results strongly suggested the occurrence of a second N-conserving process under oak, i.e. dissimilatory nitrate reduction to ammonium (DNRA). This is unexpected for a temperate forest soil under enhanced N deposition, as this process has mainly been described for unpolluted soils.

Vision-based weld pool boundary extraction and width measurement during keyhole fiber laser welding

NASA Astrophysics Data System (ADS)

Luo, Masiyang; Shin, Yung C.

2015-01-01

In keyhole fiber laser welding processes, the weld pool behavior is essential to determining welding quality. To better observe and control the welding process, the accurate extraction of the weld pool boundary as well as the width is required. This work presents a weld pool edge detection technique based on an off axial green illumination laser and a coaxial image capturing system that consists of a CMOS camera and optic filters. According to the difference of image quality, a complete developed edge detection algorithm is proposed based on the local maximum gradient of greyness searching approach and linear interpolation. The extracted weld pool geometry and the width are validated by the actual welding width measurement and predictions by a numerical multi-phase model.

Exploration of oxide-based diluted magnetic semiconductors toward transparent spintronics

NASA Astrophysics Data System (ADS)

Fukumura, T.; Yamada, Y.; Toyosaki, H.; Hasegawa, T.; Koinuma, H.; Kawasaki, M.

2004-02-01

A review is given for the recent progress of research in the field of oxide-based diluted magnetic semiconductor (DMS), which was triggered by combinatorial discovery of transparent ferromagnet. The possible advantages of oxide semiconductor as a host of DMS are described in comparison with conventional compound semiconductors. Limits and problems for identifying novel ferromagnetic DMS are described in view of recent reports in this field. Several characterization techniques are proposed in order to eliminate unidentified ferromagnetism of oxide-based DMS unidentified ferromagnetic oxide (UFO). Perspectives and possible devices are also given.

Aluminium. II - A review of deformation properties of high purity aluminium and dilute aluminium alloys.

NASA Technical Reports Server (NTRS)

Reed, R. P.

1972-01-01

The elastic and plastic deformation behavior of high-purity aluminum and of dilute aluminum alloys is reviewed. Reliable property data, including elastic moduli, elastic coefficients, tensile, creep, fatigue, hardness, and impact are presented. Single crystal tensile results are discussed. Rather comprehensive reference lists, containing publications of the past 20 years, are included for each of the above categories. Defect structures and mechanisms responsible for mechanical behavior are presented. Strengthening techniques (alloys, cold work, irradiation, quenching, composites) and recovery are briefly reviewed.

DOSY Analysis of Micromolar Analytes: Resolving Dilute Mixtures by SABRE Hyperpolarization.

PubMed

Reile, Indrek; Aspers, Ruud L E G; Tyburn, Jean-Max; Kempf, James G; Feiters, Martin C; Rutjes, Floris P J T; Tessari, Marco

2017-07-24

DOSY is an NMR spectroscopy technique that resolves resonances according to the analytes' diffusion coefficients. It has found use in correlating NMR signals and estimating the number of components in mixtures. Applications of DOSY in dilute mixtures are, however, held back by excessively long measurement times. We demonstrate herein, how the enhanced NMR sensitivity provided by SABRE hyperpolarization allows DOSY analysis of low-micromolar mixtures, thus reducing the concentration requirements by at least 100-fold. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Regeneration of strong-base anion-exchange resins by sequential chemical displacement

DOEpatents

Brown, Gilbert M.; Gu, Baohua; Moyer, Bruce A.; Bonnesen, Peter V.

2002-01-01

A method for regenerating strong-base anion exchange resins utilizing a sequential chemical displacement technique with new regenerant formulation. The new first regenerant solution is composed of a mixture of ferric chloride, a water-miscible organic solvent, hydrochloric acid, and water in which tetrachloroferrate anion is formed and used to displace the target anions on the resin. The second regenerant is composed of a dilute hydrochloric acid and is used to decompose tetrachloroferrate and elute ferric ions, thereby regenerating the resin. Alternative chemical displacement methods include: (1) displacement of target anions with fluoroborate followed by nitrate or salicylate and (2) displacement of target anions with salicylate followed by dilute hydrochloric acid. The methodology offers an improved regeneration efficiency, recovery, and waste minimization over the conventional displacement technique using sodium chloride (or a brine) or alkali metal hydroxide.

A novel technique to determine cobalt exchangeability in soils using isotope dilution.

PubMed

Wendling, Laura A; Kirby, Jason K; McLaughlin, Michael J

2008-01-01

The environmental risk posed by Co contamination is largely a function of its oxidation state. Our objective was to assess the potential biological availability of Co and the reactions and fate of soluble Co(II) after addition to soils with varying physical and chemical characteristics. A potential risk in quantifying exchangeable Co in soils using isotope dilution techniques is the possible presence of two species of Co in soil solution and adsorbed on soil solid phases [Co(II) and Co(III)], coupled with the possibility that when an isotope of Co is added it may undergo a change in oxidation state during the measurement phase. In this study, we have utilized an isotope dilution technique with cation exchange and high-performance liquid chromatography-inductively coupled plasma-mass spectrometry to determine the isotopically exchangeable Co fraction in several soils with varying characteristics such as differing Al, Fe, and Mn oxide content; pH; and organic carbon content. The application of the cation exchange procedure adjusts measurements of isotopically exchangeable Co to correct for the presence of non-exchangeable 57Co not in equilibrium with the solution phase. Results indicated that oxidation of added 57Co(II) to 57Co(III) or precipitation of 57Co(II) may occur on the surfaces of some soils, particularly those with a high pH or substantial quantities of Mn oxide minerals. No detectable Co(III)(aq) was found in the aqueous extracts of the soils examined.

Who is a cardiologist: Usurpers spawn?

PubMed Central

Mishra, Sundeep

2015-01-01

Cerebrovascular disease is the number one killer worldwide. It is increasing in epidemic proportion in developing countries as well, including India. Trained cardiologists are few and scattered in urban areas and there exists a huge shortage of personnel in clinical arena of cardiology specialty. The problem is manifest not only in diagnostics but also in treatment. This space is appropriated by a large number of clinical professionals posing as true cardiologists. Thus, currently there is a critical need to define who can be called a cardiologist and who can be accorded the privilege to treat and even perform interventional procedures. Further, the only credible way to fill this gap is to increase the infrastructure, the staff and the number of teaching, academic hospitals so that there could be an increase in the number of trained cardiologists. Alternate approach to dilute the educational, skill, and experience requirements of the physicians so that more can qualify to be called as cardiologists is likely to be counter-productive since this approach will lead to dilution in the quality of cardiologists which will consequently lead to dilution in the quality of health-care delivery. Further, the irony of matter is that while the pool of cardiologist is increased with the plea of serving rural areas, the hard reality is that very few if any of these so-called trained physicians ever serve the rural area. Thus, it is in this context the tendency to follow the second course should be firmly resisted as also the need to define “who is a cardiologist.” PMID:26702675

Effect of combined physico-chemical processes on the phytotoxicity of olive mill wastewaters.

PubMed

Andreozzi, Roberto; Canterino, Marisa; Di Somma, Ilaria; Lo Giudice, Roberto; Marotta, Raffaele; Pinto, Gabriele; Pollio, Antonino

2008-03-01

A pool of laboratory experiments is planned with the aim of evaluating the possibility to reduce the phytotoxicity of olive mill wastewater (OMW) with combined physico-chemical processes (centrifugation-ozonation, centrifugation-solar photolysis, centrifugation-solar modified photoFenton, centrifugation-solar modified photoFenton-ozonation). A moderate COD removal of an OMW is reached by using ozonation or solar modified photoFenton separately or solar modified photoFenton/O(3) combined process even for prolonged treatment times. The O(3)-treated OMWs are still toxic towards algal growth (Pseudokirchneriella subcapitata) and only for dilutions equal to or higher than 1:160 a stimulation of algal growth is observed. The sole ozonation does not reduce significantly the phytotoxicity of tested OMW measured through the GI calculation of Raphanus sativus L., Cucumis sativus L. and Lactuca sativa L. A marked reduction of OMW inhibition, higher than 50%, is evidenced for 1:8 dilution OMW samples ozonated for 2h. The long-term storage of OMW associated with solar irradiation without or with Fe(III) ions under continuous aeration is less efficient than ozonation, and the combined action of the two former treatments does not significantly contribute to enhance both COD removal and germination index. Better results are obtained on seed germination and root elongation of plantlets of the three selected species, which germinated on OMW-free solidified medium and were then transferred on a solidified culture medium containing O(3)-treated OMW diluted 1:2 and 1:4. The operating costs are estimated for the solar modified photoFenton-ozonation process.

Nitrate addition to groundwater impacted by ethanol-blended fuel accelerates ethanol removal and mitigates the associated metabolic flux dilution and inhibition of BTEX biodegradation

NASA Astrophysics Data System (ADS)

Corseuil, Henry Xavier; Gomez, Diego E.; Schambeck, Cássio Moraes; Ramos, Débora Toledo; Alvarez, Pedro J. J.

2015-03-01

A comparison of two controlled ethanol-blended fuel releases under monitored natural attenuation (MNA) versus nitrate biostimulation (NB) illustrates the potential benefits of augmenting the electron acceptor pool with nitrate to accelerate ethanol removal and thus mitigate its inhibitory effects on BTEX biodegradation. Groundwater concentrations of ethanol and BTEX were measured 2 m downgradient of the source zones. In both field experiments, initial source-zone BTEX concentrations represented less than 5% of the dissolved total organic carbon (TOC) associated with the release, and measurable BTEX degradation occurred only after the ethanol fraction in the multicomponent substrate mixture decreased sharply. However, ethanol removal was faster in the nitrate amended plot (1.4 years) than under natural attenuation conditions (3.0 years), which led to faster BTEX degradation. This reflects, in part, that an abundant substrate (ethanol) can dilute the metabolic flux of target pollutants (BTEX) whose biodegradation rate eventually increases with its relative abundance after ethanol is preferentially consumed. The fate and transport of ethanol and benzene were accurately simulated in both releases using RT3D with our general substrate interaction module (GSIM) that considers metabolic flux dilution. Since source zone benzene concentrations are relatively low compared to those of ethanol (or its degradation byproduct, acetate), our simulations imply that the initial focus of cleanup efforts (after free-product recovery) should be to stimulate the degradation of ethanol (e.g., by nitrate addition) to decrease its fraction in the mixture and speed up BTEX biodegradation.

Nitrate addition to groundwater impacted by ethanol-blended fuel accelerates ethanol removal and mitigates the associated metabolic flux dilution and inhibition of BTEX biodegradation.

PubMed

Corseuil, Henry Xavier; Gomez, Diego E; Schambeck, Cássio Moraes; Ramos, Débora Toledo; Alvarez, Pedro J J

2015-03-01

A comparison of two controlled ethanol-blended fuel releases under monitored natural attenuation (MNA) versus nitrate biostimulation (NB) illustrates the potential benefits of augmenting the electron acceptor pool with nitrate to accelerate ethanol removal and thus mitigate its inhibitory effects on BTEX biodegradation. Groundwater concentrations of ethanol and BTEX were measured 2 m downgradient of the source zones. In both field experiments, initial source-zone BTEX concentrations represented less than 5% of the dissolved total organic carbon (TOC) associated with the release, and measurable BTEX degradation occurred only after the ethanol fraction in the multicomponent substrate mixture decreased sharply. However, ethanol removal was faster in the nitrate amended plot (1.4 years) than under natural attenuation conditions (3.0 years), which led to faster BTEX degradation. This reflects, in part, that an abundant substrate (ethanol) can dilute the metabolic flux of target pollutants (BTEX) whose biodegradation rate eventually increases with its relative abundance after ethanol is preferentially consumed. The fate and transport of ethanol and benzene were accurately simulated in both releases using RT3D with our general substrate interaction module (GSIM) that considers metabolic flux dilution. Since source zone benzene concentrations are relatively low compared to those of ethanol (or its degradation byproduct, acetate), our simulations imply that the initial focus of cleanup efforts (after free-product recovery) should be to stimulate the degradation of ethanol (e.g., by nitrate addition) to decrease its fraction in the mixture and speed up BTEX biodegradation. Copyright © 2014 Elsevier B.V. All rights reserved.

Microcoupon Assay Of Adhesion And Growth Of Bacterial Films

NASA Technical Reports Server (NTRS)

Pierson, Duane L.; Koenig, David W.

1994-01-01

Microbiological assay technique facilitates determination of some characteristics of sessile bacteria like those that attach to and coat interior walls of water-purification systems. Biofilms cause sickness and interfere with purification process. Technique enables direct measurement of rate of attachment of bacterial cells, their metabolism, and effects of chemicals on them. Used to quantify effects of both bactericides and growth-stimulating agents and in place of older standard plate-count and tube-dilution techniques.

Improving the Efficiency of 3-D Hydrogeological Mixers: Dilution Enhancement Via Coupled Engineering-Induced Transient Flows and Spatial Heterogeneity

NASA Astrophysics Data System (ADS)

Di Dato, Mariaines; de Barros, Felipe P. J.; Fiori, Aldo; Bellin, Alberto

2018-03-01

Natural attenuation and in situ oxidation are commonly considered as low-cost alternatives to ex situ remediation. The efficiency of such remediation techniques is hindered by difficulties in obtaining good dilution and mixing of the contaminant, in particular if the plume deformation is physically constrained by an array of wells, which serves as a containment system. In that case, dilution may be enhanced by inducing an engineered sequence of injections and extractions from such pumping system, which also works as a hydraulic barrier. This way, the aquifer acts as a natural mixer, in a manner similar to the industrialized engineered mixers. Improving the efficiency of hydrogeological mixers is a challenging task, owing to the need to use a 3-D setup while relieving the computational burden. Analytical solutions, though approximated, are a suitable and efficient tool to seek the optimum solution among all possible flow configurations. Here we develop a novel physically based model to demonstrate how the combined spatiotemporal fluctuations of the water fluxes control solute trajectories and residence time distributions and therefore, the effectiveness of contaminant plume dilution and mixing. Our results show how external forcing configurations are capable of inducing distinct time-varying groundwater flow patterns which will yield different solute dilution rates.

Sterility and Stability of Diluted Carprofen in a Multidose Vial in the Laboratory Animal Setting.

PubMed

Simonek, Gregory D; Alarcio, Gwendolyne G; Brignolo, Laurie L

2017-05-01

Using compounded multidose vials (cMDV) is a common practice in the laboratory animal setting, where medications often are diluted to provide appropriate doses to rodents. However, bacterial contamination of MDV has been well established in both the human and veterinary medical literature. For this study, we created 14 cMDV by diluting carprofen into sterile water (dilution, 1:10) and stored 6 cMDV each at 5 and 24 °C. The stoppers of the cMDV were not cleaned with alcohol, and all were punctured twice daily for 28 d. The sterility of the diluted carprofen was evaluated by assessing bacterial growth on days 0, 7, 14, 21, and 28 and by testing for bacterial endotoxin on days 0 and 28. We used liquid chromatography-tandem mass spectrometry to assess the stability of 2 cMDV, with each cMDV being divided into the 2 storage-temperature subsets for days 0, 7, 14, 21, and 28. Neither bacterial contamination nor endotoxin was detected, and drug stability was stable over the 28 d. We suggest that with pragmatic techniques, such as secondary containment and consistent use of new needles, the contents of cMDV can remain sterile and stable for 28 d.

Sterility and Stability of Diluted Carprofen in a Multidose Vial in the Laboratory Animal Setting

PubMed Central

Simonek, Gregory D; Alarcio, Gwendolyne G; Brignolo, Laurie L

2017-01-01

Using compounded multidose vials (cMDV) is a common practice in the laboratory animal setting, where medications often are diluted to provide appropriate doses to rodents. However, bacterial contamination of MDV has been well established in both the human and veterinary medical literature. For this study, we created 14 cMDV by diluting carprofen into sterile water (dilution, 1:10) and stored 6 cMDV each at 5 and 24 °C. The stoppers of the cMDV were not cleaned with alcohol, and all were punctured twice daily for 28 d. The sterility of the diluted carprofen was evaluated by assessing bacterial growth on days 0, 7, 14, 21, and 28 and by testing for bacterial endotoxin on days 0 and 28. We used liquid chromatography–tandem mass spectrometry to assess the stability of 2 cMDV, with each cMDV being divided into the 2 storage-temperature subsets for days 0, 7, 14, 21, and 28. Neither bacterial contamination nor endotoxin was detected, and drug stability was stable over the 28 d. We suggest that with pragmatic techniques, such as secondary containment and consistent use of new needles, the contents of cMDV can remain sterile and stable for 28 d. PMID:28535864

Nucleation mode particles with a nonvolatile core in the exhaust of a heavy duty diesel vehicle.

PubMed

Rönkkö, Topi; Virtanen, Annele; Kannosto, Jonna; Keskinen, Jorma; Lappi, Maija; Pirjola, Liisa

2007-09-15

The characteristics of the nucleation mode particles of a Euro IV heavy-duty diesel vehicle exhaust were studied. The NOx and PM emissions of the vehicle were controlled through the use of cooled EGR and high-pressure fuel injection techniques; no exhaust gas after-treatment was used. Particle measurements were performed in vehicle laboratory and on road. Nucleation mode dominated the particle number size distribution in all the tested driving conditions. According to the on-road measurements, the nucleation mode was already formed after 0.7 s residence time in the atmosphere and no significant changes were observed for longer residence times. The nucleation mode was insensitive to the fuel sulfur content, dilution air temperature, and relative humidity. An increase in the dilution ratio decreased the size of the nucleation mode particles. This behavior was observed to be linked to the total hydrocarbon concentration in the diluted sample. In volatility measurements, the nucleation mode particles were observed to have a nonvolatile core with volatile species condensed on it. The results indicate that the nucleation mode particles have a nonvolatile core formed before the dilution process. The core particles have grown because of the condensation of semivolatile material, mainly hydrocarbons, during the dilution.

Dilution of protein-surfactant complexes: a fluorescence study.

PubMed

Azadi, Glareh; Chauhan, Anuj; Tripathi, Anubhav

2013-09-01

Dilution of protein-surfactant complexes is an integrated step in microfluidic protein sizing, where the contribution of free micelles to the overall fluorescence is reduced by dilution. This process can be further improved by establishing an optimum surfactant concentration and quantifying the amount of protein based on the fluorescence intensity. To this end, we study the interaction of proteins with anionic sodium dodecyl sulfate (SDS) and cationic hexadecyl trimethyl ammonium bromide (CTAB) using a hydrophobic fluorescent dye (sypro orange). We analyze these interactions fluourometrically with bovine serum albumin, carbonic anhydrase, and beta-galactosidase as model proteins. The fluorescent signature of protein-surfactant complexes at various dilution points shows three distinct regions, surfactant dominant, breakdown, and protein dominant region. Based on the dilution behavior of protein-surfactant complexes, we propose a fluorescence model to explain the contribution of free and bound micelles to the overall fluorescence. Our results show that protein peak is observed at 3 mM SDS as the optimum dilution concentration. Furthermore, we study the effect of protein concentration on fluorescence intensity. In a single protein model with a constant dye quantum yield, the peak height increases with protein concentration. Finally, addition of CTAB to the protein-SDS complex at mole fractions above 0.1 shifts the protein peak from 3 mM to 4 mM SDS. The knowledge of protein-surfactant interactions obtained from these studies provides significant insights for novel detection and quantification techniques in microfluidics. © 2013 The Protein Society.

Biocompatibility of hydroxyapatite coatings deposited by pulse electrodeposition technique on the Nitinol superelastic alloy.

PubMed

Marashi-Najafi, F; Khalil-Allafi, J; Etminanfar, M R

2017-07-01

The present study deals with pulse electrochemical deposition of HA on NiTi alloy and in vitro evaluation of coatings. At first step, a thermo-chemical surface modification process was applied to control the Ni release of the alloy. The electrochemical deposition of CaP coatings was examined at both dilute and concentrated solutions. The morphology and the composition of coatings were studied using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Plate like and needle like morphologies were formed for dilute and concentrated solution respectively and HA phase was formed by increasing the pulse current density for both electrolyte. The thickness of the samples was measured using cross sectioning technique. Fibroblast cell culture test on the coated samples revealed that the HA coating obtained by dilute solution shows the best biocompatibility. Also, MTT assay showed the highest cell density and cell proliferation after 5days for the HA coating of dilute solution. The contact angle of samples was measured and the coated samples showed a hydrophilic surface. Soaking the sample in SBF revealed that the crystallization rate of calcium-phosphate compounds is higher on the plate like HA coating as compared to the needle like morphology. The P release of the HA coated samples was measured in a physiological saline solution and the results show that the ions releasing in the plate like coating are less than the needle like coating. It seems that the stability of the plate like coating in biological environments is responsible for the better biocompatibility of the coating. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimentally evaluating the origin of dilute magnetism in nanomaterials

NASA Astrophysics Data System (ADS)

Pereira, L. M. C.

2017-10-01

Reports of room-temperature ferromagnetism continue to emerge for an ever-growing range of nanomaterials with a small or even vanishing concentration of magnetic atoms. Dilute magnetic semiconductors (DMS) are the most representative class of such materials, but similar magnetic properties have been reported in many others. Challenging our understanding of magnetic order in solids, as well as our ability to experimentally assess it, these remarkable magnetic phenomena have become one of the most controversial topics in magnetism. Various non-intrinsic sources of ferromagnetism (e.g. instrumental artifacts and magnetic contamination) are becoming well documented, and rarely are all of them taken into account when room-temperature ferromagnetism is reported. This topical review is intended to serve as a guide when evaluating to what extent a given data set supports the claim of intrinsic ferromagnetism in dilute nanomaterials. It compiles the most relevant sources of non-intrinsic ferromagnetism which have been reported, as well as guidelines for how to minimize them. It also provides an overview of complementary structural and magnetic characterization techniques which can be combined to provide different levels of scrutiny of the intrinsic nature of experimentally observed ferromagnetism. In particular, it gives some notable examples of how comprehensive studies based on those techniques have led to a remarkably detailed understanding of model DMS materials, with strong evidence of absence of room-temperature ferromagnetism. Although mostly based on DMS research, this review provides a set of guidelines and cautionary notes of broader relevance, including some emerging new fields of dilute nanomagnetism such as magnetically doped 3D topological insulators, 3D Dirac semimetals, and 2D materials.

Charged excitons in a dilute two-dimensional electron gas in a high magnetic field

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

Wojs, Arkadiusz; Institute of Physics, Wroclaw University of Technology, Wroclaw 50-370,; Quinn, John J.

2000-08-15

A theory of charged excitons X{sup -} in a dilute two-dimensional (2D) electron gas in a high-magnetic field is presented. In contrast to previous calculations, three bound X{sup -} states (one singlet and two triplets) are found in a narrow and symmetric GaAs quantum well. The singlet and a ''bright'' triplet are the two optically active states observed in experiments. The bright triplet has the binding energy of about 1 meV, smaller than the singlet and a ''dark'' triplet. The interaction of bound X{sup -}'s with a dilute 2D electron gas is investigated using exact diagonalization techniques. It is foundmore » that the short-range character of the e-X{sup -} interactions effectively isolates bound X{sup -} states from a dilute e-h plasma. This results in the insensitivity of the photoluminescence spectrum to the filling factor {nu}, and a rapid decrease of the oscillator strength of the dark triplet X{sup -} as a function of {nu}{sup -1}. (c) 2000 The American Physical Society.« less

Bioimpedance and Fluid Status in Children and Adolescents Treated With Dialysis.

PubMed

Milani, Gregorio P; Groothoff, Jaap W; Vianello, Federica A; Fossali, Emilio F; Paglialonga, Fabio; Edefonti, Alberto; Agostoni, Carlo; Consonni, Dario; van Harskamp, Dewi; van Goudoever, Johannes B; Schierbeek, Henk; Oosterveld, Michiel J S

2017-03-01

Assessment of hydration status in patients with chronic kidney failure treated by dialysis is crucial for clinical management decisions. Dilution techniques are considered the gold standard for measurement of body fluid volumes, but they are unfit for day-to-day care. Multifrequency bioimpedance has been shown to be of help in clinical practice in adults and its use in children and adolescents has been advocated. We investigated whether application of multifrequency bioimpedance is appropriate for total-body water (TBW) and extracellular water (ECW) measurement in children and adolescents on dialysis therapy. A study of diagnostic test accuracy. 16 young dialysis patients (before a hemodialysis session or after peritoneal dialysis treatment) from the Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy, and the Emma Children's Hospital-Academic Medical Center, Amsterdam, the Netherlands. TBW and ECW volumes assessed by multifrequency bioimpedance. TBW and ECW volumes measured by deuterium and bromide dilution, respectively. Mean TBW volumes determined by multifrequency bioimpedance and deuterium dilution were 19.2±8.7 (SD) and 19.3±8.3L, respectively; Bland-Altman analysis showed a mean bias between the 2 methods of -0.09 (95% limits of agreement, -2.1 to 1.9) L. Mean ECW volumes were 8.9±4.0 and 8.3±3.3L measured by multifrequency bioimpedance and bromide dilution, respectively; mean bias between the 2 ECW measurements was +0.6 (95% limits of agreement, -2.3 to 3.5). Participants ingested the deuterated water at home without direct supervision by investigators, small number of patients, repeated measurements in individual patients were not performed. Multifrequency bioimpedance measurements were unbiased but imprecise in comparison to dilution techniques. We conclude that multifrequency bioimpedance measurements cannot precisely estimate TBW and ECW in children receiving dialysis. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Thin film silicon by a microwave plasma deposition technique: Growth and devices, and, interface effects in amorphous silicon/crystalline silicon solar cells

NASA Astrophysics Data System (ADS)

Jagannathan, Basanth

Thin film silicon (Si) was deposited by a microwave plasma CVD technique, employing double dilution of silane, for the growth of low hydrogen content Si films with a controllable microstructure on amorphous substrates at low temperatures (<400sp°C). The double dilution was achieved by using a Ar (He) carrier for silane and its subsequent dilution by Hsb2. Structural and electrical properties of the films have been investigated over a wide growth space (temperature, power, pressure and dilution). Amorphous Si films deposited by silane diluted in He showed a compact nature and a hydrogen content of ˜8 at.% with a photo/dark conductivity ratio of 10sp4. Thin film transistors (W/L = 500/25) fabricated on these films, showed an on/off ratio of ˜10sp6 and a low threshold voltage of 2.92 volts. Microcrystalline Si films with a high crystalline content (˜80%) were also prepared by this technique. Such films showed a dark conductivity ˜10sp{-6} S/cm, with a conduction activation energy of 0.49 eV. Film growth and properties have been compared for deposition in Ar and He carrier systems and growth models have been proposed. Low temperature junction formation by undoped thin film silicon was examined through a thin film silicon/p-type crystalline silicon heterojunctions. The thin film silicon layers were deposited by rf glow discharge, dc magnetron sputtering and microwave plasma CVD. The hetero-interface was identified by current transport analysis and high frequency capacitance methods as the key parameter controlling the photovoltaic (PV) response. The effect of the interface on the device properties (PV, junction, and carrier transport) was examined with respect to modifications created by chemical treatment, type of plasma species, their energy and film microstructure interacting with the substrate. Thermally stimulated capacitance was used to determine the interfacial trap parameters. Plasma deposition of thin film silicon on chemically clean c-Si created electron trapping sites while hole traps were seen when a thin oxide was present at the interface. Under optimized conditions, a 10.6% efficient cell (11.5% with SiOsb2 A/R) with an open circuit voltage of 0.55 volts and a short circuit current density of 30 mA/cmsp2 was fabricated.

Recent Progress in Measuring and Modeling Patterns of Biomass and Soil Carbon Pools Across the Amazon Basin

NASA Technical Reports Server (NTRS)

Potter, Christopher; Malhi, Yadvinder

2004-01-01

Ever more detailed representations of above-ground biomass and soil carbon pools have been developed during the LBA project. Environmental controls such as regional climate, land cover history, secondary forest regrowth, and soil fertility are now being taken into account in regional inventory studies. This paper will review the evolution of measurement-extrapolation approaches, remote sensing, and simulation modeling techniques for biomass and soil carbon pools, which together help constrain regional carbon budgets and enhance in our understanding of uncertainty at the regional level.

Habitat properties are key drivers of Borrelia burgdorferi (s.l.) prevalence in Ixodes ricinus populations of deciduous forest fragments.

PubMed

Ehrmann, Steffen; Ruyts, Sanne C; Scherer-Lorenzen, Michael; Bauhus, Jürgen; Brunet, Jörg; Cousins, Sara A O; Deconchat, Marc; Decocq, Guillaume; De Frenne, Pieter; De Smedt, Pallieter; Diekmann, Martin; Gallet-Moron, Emilie; Gärtner, Stefanie; Hansen, Karin; Kolb, Annette; Lenoir, Jonathan; Lindgren, Jessica; Naaf, Tobias; Paal, Taavi; Panning, Marcus; Prinz, Maren; Valdés, Alicia; Verheyen, Kris; Wulf, Monika; Liira, Jaan

2018-01-08

The tick Ixodes ricinus has considerable impact on the health of humans and other terrestrial animals because it transmits several tick-borne pathogens (TBPs) such as B. burgdorferi (sensu lato), which causes Lyme borreliosis (LB). Small forest patches of agricultural landscapes provide many ecosystem services and also the disservice of LB risk. Biotic interactions and environmental filtering shape tick host communities distinctively between specific regions of Europe, which makes evaluating the dilution effect hypothesis and its influence across various scales challenging. Latitude, macroclimate, landscape and habitat properties drive both hosts and ticks and are comparable metrics across Europe. Therefore, we instead assess these environmental drivers as indicators and determine their respective roles for the prevalence of B. burgdorferi in I. ricinus. We sampled I. ricinus and measured environmental properties of macroclimate, landscape and habitat quality of forest patches in agricultural landscapes along a European macroclimatic gradient. We used linear mixed models to determine significant drivers and their relative importance for nymphal and adult B. burgdorferi prevalence. We suggest a new prevalence index, which is pool-size independent. During summer months, our prevalence index varied between 0 and 0.4 per forest patch, indicating a low to moderate disservice. Habitat properties exerted a fourfold larger influence on B. burgdorferi prevalence than macroclimate and landscape properties combined. Increasingly available ecotone habitat of focal forest patches diluted and edge density at landscape scale amplified B. burgdorferi prevalence. Indicators of habitat attractiveness for tick hosts (food resources and shelter) were the most important predictors within habitat patches. More diverse and abundant macro- and microhabitat had a diluting effect, as it presumably diversifies the niches for tick-hosts and decreases the probability of contact between ticks and their hosts and hence the transmission likelihood. Diluting effects of more diverse habitat patches would pose another reason to maintain or restore high biodiversity in forest patches of rural landscapes. We suggest classifying habitat patches by their regulating services as dilution and amplification habitat, which predominantly either decrease or increase B. burgdorferi prevalence at local and landscape scale and hence LB risk. Particular emphasis on promoting LB-diluting properties should be put on the management of those habitats that are frequently used by humans. In the light of these findings, climate change may be of little concern for LB risk at local scales, but this should be evaluated further.

H3-THYMIDINE DERIVATIVE POOLS IN RELATION TO MACRONUCLEAR DNA SYNTHESIS IN TETRAHYMENA PYRIFORMIS

PubMed Central

Stone, G. E.; Miller, O. L.; Prescott, D. M.

1965-01-01

The formation of a soluble H3-thymidine derivative pool has been examined in Tetrahymena pyriformis as a function of macronuclear DNA synthesis during the cell life cycle. An autoradiographic technique which allows the detection of water-soluble materials within a cell has shown that these cells do not take up and retain exogenous H3-thymidine during G1 or G2. Uptake of H3-thymidine is restricted to the S period of the cell cycle. Additional autoradiographic experiments show, however, that a soluble pool of H3-thymidine derivatives persists from the end of one DNA synthesis period to the beginning of the next synthesis period in the subsequent cell cycle. Since this persisting pool cannot be labeled with H3-thymidine, the pool does not turn over during non-S periods. PMID:19866660

High individual variation in pheromone production by tree-killing bark beetles (Coleoptera: Curculionidae: Scolytinae)

NASA Astrophysics Data System (ADS)

Pureswaran, Deepa S.; Sullivan, Brian T.; Ayres, Matthew P.

2008-01-01

Aggregation via pheromone signalling is essential for tree-killing bark beetles to overcome tree defenses and reproduce within hosts. Pheromone production is a trait that is linked to fitness, so high individual variation is paradoxical. One explanation is that the technique of measuring static pheromone pools overestimates true variation among individuals. An alternative hypothesis is that aggregation behaviour dilutes the contribution of individuals to the trait under selection and reduces the efficacy of natural selection on pheromone production by individuals. We compared pheromone measurements from traditional hindgut extractions of female southern pine beetles with those obtained by aerating individuals till they died. Aerations showed greater total pheromone production than hindgut extractions, but coefficients of variation (CV) remained high (60-182%) regardless of collection technique. This leaves the puzzle of high variation unresolved. A novel but simple explanation emerges from considering bark beetle aggregation behaviour. The phenotype visible to natural selection is the collective pheromone plume from hundreds of colonisers. The influence of a single beetle on this plume is enhanced by high variation among individuals but constrained by large group sizes. We estimated the average contribution of an individual to the pheromone plume across a range of aggregation sizes and showed that large aggregation sizes typical in mass attacks limit the potential of natural selection because each individual has so little effect on the overall plume. Genetic variation in pheromone production could accumulate via mutation and recombination, despite strong effects of the pheromone plume on the fitness of individuals within the aggregation. Thus, aggregation behaviour, by limiting the efficacy of natural selection, can allow the persistence of extreme phenotypes in nature.

Effect of chilling temperature on the long-term survival of rabbit spermatozoa held either in a tris-based or a jellified extender.

PubMed

Rosato, Mp; Iaffaldano, N

2011-04-01

As the preservation of the fertilizing capacity of rabbit spermatozoa for several days after semen collection remains a major target for the artificial insemination programs of rabbit breeding, a study was conducted to compare the efficacy of 5 or 15°C as holding temperature in lengthening the preservability of rabbit semen quality during 192 h of storage both in a solid (Cunigel) and a liquid (Tris-Citric acid-Glucose; TCG) extender. Six pooled semen samples (two ejaculates/male; two-three males/pool) were taken and made four aliquots: two aliquots were tenfold diluted with the TCG extender, whereas the other two were tenfold diluted with the Cunigel extender. One aliquot per diluent was stored at 5°C and the second one at 15°C. Sperm motility (light microscope), viability (SyBr-PI staining), plasma membrane functional integrity (Hypo-osmotic swelling test) and acrosome integrity (PSA-FITC staining) were recorded at 0, 48, 120 and 192 h of storage. In liquid-stored spermatozoa, mass motility and viability were significantly higher (p ≤ 0.05) in samples stored at 5°C than at 15°C at all the storage times; at 5°C resulted also higher (p ≤ 0.05) the percentages of both forward motility at 48 h and sperm functional integrity at 120 and 192 h of storage, whereas chilling temperature did not affect acrosome integrity. With the Cunigel extender, all the semen qualitative parameters were significantly higher in sample stored at 5 than 15°C over storage time (p ≤ 0.05); only acrosome integrity at 192 h was not different according to the chilling temperatures. In conclusion, 5°C were better than 15°C for the long-term storage of rabbit semen both in the TCG and Cunigel extender. © 2010 Blackwell Verlag GmbH.

Effect of antioxidants on post thaw microscopic, oxidative stress parameter and fertility of Boer goat spermatozoa in Tris egg yolk glycerol extender.

PubMed

Memon, Akeel Ahmed; Wahid, H; Rosnina, Y; Goh, Y M; Ebrahimi, M; Nadia, F M

2012-12-01

This study was conducted to determine the effect of antioxidants on standard semen parameters, lipid peroxidation and fertility of Boer goat semen after cryopreservation. Ejaculates from four bucks were collected, evaluated and pooled at 37°C. The pooled semen was diluted with Tris citric acid fructose for washing. Semen samples, which were diluted with a Tris-based extender containing the antioxidant ascorbic acid (8.5mg/ml), butylated hydroxytoluene (2mM), cysteine (5mM) and hypotaurine (10mM) and an extender without antioxidant supplementation were cooled to 4°C and frozen in 0.25 straws with programmable freezer and finally stored in liquid nitrogen. Data (10 replicates) were analyzed by one-way analysis of variance. Mean (±SEM) progressive motility was significantly higher in ascorbic acid than other supplement groups and control samples (P>0.05). Best values were observed in ascorbic acid followed by BHT, cysteine, and hypotaurine. Antioxidant supplementation in extender showed significant (P<0.05) better values than the control group for sperm membrane integrity, acrosome integrity and viability. The ability of antioxidants to reduce the lipid peroxidation (LPO) after freeze thawing was measured by the formation of malondialdehyde (MDA) using the thiobarbituric acid method. Results showed that addition of antioxidants significantly reduced the rate of LPO in comparison to control (P<0.05). Ascorbic acid exhibited better values (1.27±0.28), than butylated hydroxytoluene, cysteine and hypotaurine 1.32±0.42, 2.27±0.16 and 2.38±0.17 respectively, which are significantly better than control (3.52±0.54). Higher pregnancy rate was observed with ascorbic acid followed by butylated hydroxtolune, hypotaurine and cysteine. However, differences in the fertility rate were non-significant with hypotaurine, cysteine and control groups. Copyright © 2012 Elsevier B.V. All rights reserved.

The Effect of Sperm Concentration and Storage Vessel on Quercetin-Supplemented Rabbit Semen During Chilled Storage.

PubMed

Johinke, D; de Graaf, S P; Bathgate, R

2015-08-01

Extending the shelf life of chilled rabbit spermatozoa is vital for the expansion of the farmed rabbit industry. This study evaluated the relationship between sperm concentration and packaging on in vitro quality of chilled rabbit semen over 96 h. Semen was collected from adult bucks (n = 4) and pooled at 37°C following evaluation. Pooled ejaculates were diluted with a Tris-based extender supplemented with 100 μm quercetin to a concentration of 15, 30 or 60 × 10(6)  spermatozoa/ml, packaged into plastic tubes or 0.5-ml straws and stored at 15°C. Sperm quality was assessed by computer-assisted sperm Analysis [total motility (tMOT)] and flow cytometry [viability, acrosome integrity, H2 O2 production, plasma membrane disorder, apoptosis and DNA fragmentation index (DFI)] at 0, 48, 72 and 96 h. From 48 h, concentrations of 30 and 60 × 10(6)  spermatozoa/ml reported the highest tMOT, irrespective of storage vessel (p < 0.05). Storage in straws reduced oxidative stress and improved plasma membrane stability. The %DFI, mean DFI and SD-DFI were increased in spermatozoa stored in tubes compared with straws (p < 0.05). Although the use of low sperm concentrations in artificial insemination doses would facilitate greater dispersion of genetically superior rabbit bucks, dilution to 15 × 10(6)  spermatozoa/ml had a detrimental impact on motility. As such, chilled storage at 30 × 10(6)  spermatozoa/ml may provide a suitable balance between motility and H2 O2 production to best maintain overall sperm function and should be evaluated in a large-scale AI trial. © 2015 Blackwell Verlag GmbH.

Preliminary studies of the CHIM electrogeochemical method at the Kokomo Mine, Russell Gulch, Colorado

USGS Publications Warehouse

Smith, D.B.; Hoover, D.B.; Sanzolone, R.F.

1993-01-01

The CHIM electrogeochemical exploration technique was developed in the former Soviet Union about 20 years ago and is claimed to be effective in exploration for concealed mineral deposits that are not detectable by other geochemical or geophysical techniques. The method involves providing a high-voltage direct current to an anode and an array of special collector cathodes. Cations mobile in the electric field are collected at the cathodes and their concentrations determined. The U.S. Geological Survey started a study of the CHIM method by conducting tests over a precious- and base-metal-bearing quartz vein covered with 3 m of colluvial soil and weathered bedrock near the Kokomo Mine, Colorado. The tests show that the CHIM method gives better definition of the vein than conventional soil geochemistry based on a total-dissolution technique. The CHIM technique gives reproducible geochemical anomaly patterns, but the absolute concentrations depend on local site variability as well as temporal variations. Weak partial dissolutions of soils at the Kokomo Mine by an enzyme leach, a dilute acetic acid leach, and a dilute hydrochloric acid leach show results comparable to those from the CHIM method. This supports the idea that the CHIM technique is essentially a weak in-situ partial extraction involving only ions able to move in a weak electric field. ?? 1993.

Combined effects of pre-hardening and fall fertilization on nitrogen translocation and storage in Quercus variabilis seedlings

Treesearch

Guolei Li; Yan Zhu; Yong Liu; Jiaxi Wang; Jiajia Liu; R. Kasten Dumroese

2014-01-01

Maintaining proper seedling nitrogen status is important for outplanting success. Fall fertilization of evergreen conifer seedlings is a well-known technique for averting nitrogen (N) dilution caused by continued seedling growth during hardening. For deciduous seedlings, this technique is much less understood, and regardless of foliage type, the interaction of N status...

Dilution-to-extinction cultivation of leaf-inhabiting endophytic fungi in beech (Fagus sylvatica L.)--different cultivation techniques influence fungal biodiversity assessment.

PubMed

Unterseher, Martin; Schnittler, Martin

2009-05-01

Two cultivation-based isolation techniques - the incubation of leaf fragments (fragment plating) and dilution-to-extinction culturing on malt extract agar - were compared for recovery of foliar endophytic fungi from Fagus sylvatica near Greifswald, north-east Germany. Morphological-anatomical characters of vegetative and sporulating cultures and ITS sequences were used to assign morphotypes and taxonomic information to the isolates. Data analysis included species-accumulation curves, richness estimators, multivariate statistics and null model testing. Fragment plating and extinction culturing were significantly complementary with regard to species composition, because around two-thirds of the 35 fungal taxa were isolated with only one of the two cultivation techniques. The difference in outcomes highlights the need for caution in assessing fungal biodiversity based upon single isolation techniques. The efficiency of cultivation-based studies of fungal endophytes was significantly increased with the combination of the two isolation methods and estimations of species richness, when compared with a 20-years old reference study, which needed three times more isolates with fragment plating to attain the same species richness. Intensified testing and optimisation of extinction culturing in endophyte research is advocated.

Enhanced Detection of Vibrio Cholerae in Oyster Homogenate Based on Centrifugal Removal of Inhibitory Agents

NASA Technical Reports Server (NTRS)

Alexander, Donita; DePaola, Angelo; Young, Ronald B.

1998-01-01

The disease cholera, caused by Vibrio cholerae, has been associated with consumption of contaminated seafood, including raw oysters. Detection of V. cholerae in foods typically involves blending the oysters, diluting the homogenate in alkaline peptone water (APW), overnight enrichment, and isolation on selective agar. Unfortunately, the oyster homogenate must be diluted to large volumes because lower dilutions inhibit the growth of V. cholerae. The goals of this study were to develop an alternative to large dilutions and to evaluate the basis for the inhibition observed in lower dilutions of oyster homogenates. Centrifugation of oyster homogenates at 10,000 x g for 15 min, followed by enrichment of the resulting pellet in APW, was found to eliminate the inhibition of V. cholerae growth. Inhibition appears not to be due to competing microflora but to a component(s) released when V. cholerae grows in the presence of oyster homogenate. The inhibitory component(s) kills the V. cholerae after the cell concentration reaches > 10(exp 8) cells/mL, rather than initially preventing their growth. The pH also declines from 8.0 to 5.5 during this period; however, the pH decline by itself appears not to cause V. cholerae death. Seven strains of V. cholerae (01 and non-01) and two strains of V. vulnificus were susceptible to the inhibitory agent(s). However, other Vibrio and non-Vibrio species tested were not inhibited by the oyster homogenates. Based on digestion of oyster homogenates with pronase, trypsin and lipase, the inhibitory reaction involves a protein(s). In a preliminary trial with oyster homogenate seeded with 1 cfu/g of V. cholerae, the modified centrifugation technique detected a slightly higher percentage of samples at a 1:10 dilution than the standard FDA Bacteriological Analytical Method (BAM) detected in uncentrifuged oyster homogenate at a 1:100 dilution. V. cholerae in seeded samples could also be detected more frequently by the modified centrifugation method than by PCR at a 1:10 dilution.

Use of polymerase chain reaction technique to confirm VecTest screening results in Plasmodium falciparum and Plasmodium vivax VK 210 laboratory-infected Anopheles stephensi mosquitoes.

PubMed

Santos-Ciminera, Patricia D; Acheé, Nicole L; Quinnan, Gerald V; Roberts, Donald R

2004-09-01

We evaluated polymerase chain reaction (PCR) to confirm immunoassays for malaria parasites in mosquito pools after a failure to detect malaria with PCR during an outbreak in which pools tested positive using VecTest and enzyme-linked immunosorbent assay (ELISA). We combined VecTest, ELISA, and PCR to detect Plasmodium falciparum and Plasmodium vivax VK 210. Each mosquito pool, prepared in triplicate, consisted of 1 exposed Anopheles stephensi and up to 9 unfed mosquitoes. The results of VecTest and ELISA were concordant. DNA from a subset of the pools, 1 representative of each ratio of infected to uninfected mosquitoes, was extracted and used as template in PCR. All P. vivax pools were PCR positive but some needed additional processing for removal of apparent inhibitors before positive results were obtained. One of the pools selected for P. falciparum was negative by PCR, probably because of losses or contamination during DNA extraction; 2 remaining pools at this ratio were PCR positive. Testing pools by VecTest, ELISA, and PCR is feasible, and PCR is useful for confirmation of immunoassays. An additional step might be needed to remove potential inhibitors from pools prior to PCR.

Caught in the middle with multiple displacement amplification: the myth of pooling for avoiding multiple displacement amplification bias in a metagenome.

PubMed

Marine, Rachel; McCarren, Coleen; Vorrasane, Vansay; Nasko, Dan; Crowgey, Erin; Polson, Shawn W; Wommack, K Eric

2014-01-30

Shotgun metagenomics has become an important tool for investigating the ecology of microorganisms. Underlying these investigations is the assumption that metagenome sequence data accurately estimates the census of microbial populations. Multiple displacement amplification (MDA) of microbial community DNA is often used in cases where it is difficult to obtain enough DNA for sequencing; however, MDA can result in amplification biases that may impact subsequent estimates of population census from metagenome data. Some have posited that pooling replicate MDA reactions negates these biases and restores the accuracy of population analyses. This assumption has not been empirically tested. Using mock viral communities, we examined the influence of pooling on population-scale analyses. In pooled and single reaction MDA treatments, sequence coverage of viral populations was highly variable and coverage patterns across viral genomes were nearly identical, indicating that initial priming biases were reproducible and that pooling did not alleviate biases. In contrast, control unamplified sequence libraries showed relatively even coverage across phage genomes. MDA should be avoided for metagenomic investigations that require quantitative estimates of microbial taxa and gene functional groups. While MDA is an indispensable technique in applications such as single-cell genomics, amplification biases cannot be overcome by combining replicate MDA reactions. Alternative library preparation techniques should be utilized for quantitative microbial ecology studies utilizing metagenomic sequencing approaches.

An observational study of the ozone dilution effect: Ozone transport in the austral spring stratosphere

NASA Technical Reports Server (NTRS)

Atkinson, Roger J.; Plumb, R. Alan

1994-01-01

In a previous observational analysis, Atkinson et al (1989) ascribed a sudden decrease in Southern Hemisphere midlatitude total ozone during December 1987 to an 'ozone dilution effect' brought about by the breakup of the polar stratospheric vortex at that time. A question alluded to but unanswered by that study was the degree to which the observed total ozone decrease might have been caused by the quasi-horizontal equatorward transport of 'ozone hold' air from within the vortex, and to what degree by the vertical advection from lower levels of air naturally low in ozone, a dynamical adjustment process which must accompany the equatorward outbreak of a discrete high-latitude airmass. In the present study, analyses of Ertel potential vorticity, TOMS total ozone, and SAGE and ozone sonde vertical profile data are employed using a novel technique to examine the 1987 event in greater detail, to answer this question. Recent progress is then reported in refining the technique and extending the investigation to examine the dynamical evolution of the austral spring stratosphere during other recent years, to shed more light on the precise nature, frequency, and severity of such 'ozone dilution' events, and the effect that this process may have on long term ozone behavior in the Southern Hemisphere.

Quenching behavior of molten pool with different strategies – A review

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

Shrikant,, E-mail: 2014rmt9018@mnit.ac.in; Pandel, U.; Duchaniya, R. K.

After the major severe accident in nuclear reactor, there has been lot of concerns regarding long term core melt stabilization following a severe accident in nuclear reactors. Numerous strategies have been though for quenching and stabilization of core melt like top flooding, bottom flooding, indirect cooling, etc. However, the effectiveness of these schemes is yet to be determined properly, for which, lot of experiments are needed. Several experiments have been performed for coolability of melt pool under bottom flooding as well as for indirect cooling. Besides these tests are very scattered because they involve different simulants material initial temperatures andmore » masses of melt, which makes it very complex to judge the effectiveness of a particular technique and advantage over the other. In this review paper, a study has been carried on different cooling techniques of simulant materials with same mass. Three techniques have been compared here and the results are discussed. Under top flooding technique it took several hours to cool the melt under without decay heat condition. In bottom flooding technique was found to be the best technique among in indirect cooling technique, top flooded technique, and bottom flooded technique.« less

Diluted magnetic oxides

NASA Astrophysics Data System (ADS)

Li, XiaoLi; Qi, ShiFei; Jiang, FengXian; Quan, ZhiYong; Xu, XiaoHong

2013-01-01

In this review, we review the progress of research on ZnO- and In2O3-based diluted magnetic oxides (DMOs). Firstly, we present the preparation and characterization of DMOs. The former includes the preparation methods and conditions, and the latter includes the characterization techniques for measuring microstructures. Secondly, we introduce the magnetic and transport properties of DMOs, as well as the relationship between them. Thirdly, the origin and mechanism of the ferromagnetism are discussed. Fourthly, we introduce other related work, including computational work and pertinent heterogeneous structures, such as multilayers and magnetic tunnel junctions. Finally, we provide an overview and outlook for DMOs.

Automated fluid analysis apparatus and techniques

DOEpatents

Szecsody, James E.

2004-03-16

An automated device that couples a pair of differently sized sample loops with a syringe pump and a source of degassed water. A fluid sample is mounted at an inlet port and delivered to the sample loops. A selected sample from the sample loops is diluted in the syringe pump with the degassed water and fed to a flow through detector for analysis. The sample inlet is also directly connected to the syringe pump to selectively perform analysis without dilution. The device is airtight and used to detect oxygen-sensitive species, such as dithionite in groundwater following a remedial injection to treat soil contamination.

Changes in Lung Capillary Permeability in Renal Failure

PubMed Central

Crosbie, W. A.; Snowden, S.; Parsons, V.

1972-01-01

Excess fluid in the lung can be quantified in chronic dialysis patients by using the double indicator dilution technique. The lung capillaries show an increased permeability to sodium when these patents develop pulmonary oedema. PMID:4564763

Effect of copper and nickel doping on the optical and structural properties of ZnO

NASA Astrophysics Data System (ADS)

Muǧlu, G. Merhan; Sarıtaş, S.; ćakıcı, T.; Şakar, B.; Yıldırım, M.

2017-02-01

The present study is focused on the Cu doped ZnO and Ni doped ZnO dilute magnetic semiconductor thin films. ZnO:Cu and ZnO:Ni thin films were grown by Chemically Spray Pyrolysis (CSP) method on glass substrates. Optical analysis of the films was done spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. The structure, morphology, topology and elemental analysis of ZnO:Cu and ZnO:Ni dilute magnetic thin films were investigated by X-ray diffraction (XRD), Raman Analysis, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM) techniques, respectively. Also The magnetic properties of the ZnO:Ni thin film was investigated by vibrating sample magnetometer (VSM) method. VSM measurements of ZnO:Ni thin film showed that the ferromagnetic behavior.

Decorrelation correction for nanoparticle tracking analysis of dilute polydisperse suspensions in bulk flow

NASA Astrophysics Data System (ADS)

Hartman, John; Kirby, Brian

2017-03-01

Nanoparticle tracking analysis, a multiprobe single particle tracking technique, is a widely used method to quickly determine the concentration and size distribution of colloidal particle suspensions. Many popular tools remove non-Brownian components of particle motion by subtracting the ensemble-average displacement at each time step, which is termed dedrifting. Though critical for accurate size measurements, dedrifting is shown here to introduce significant biasing error and can fundamentally limit the dynamic range of particle size that can be measured for dilute heterogeneous suspensions such as biological extracellular vesicles. We report a more accurate estimate of particle mean-square displacement, which we call decorrelation analysis, that accounts for correlations between individual and ensemble particle motion, which are spuriously introduced by dedrifting. Particle tracking simulation and experimental results show that this approach more accurately determines particle diameters for low-concentration polydisperse suspensions when compared with standard dedrifting techniques.

Effect of different analyte diffusion/adsorption protocols on SERS signals

NASA Astrophysics Data System (ADS)

Li, Ruoping; Petschek, Rolfe G.; Han, Junhe; Huang, Mingju

2018-07-01

The effect of different analyte diffusion/adsorption protocols was studied which is often overlooked in surface-enhanced Raman scattering (SERS) technique. Three protocols: highly concentrated dilution (HCD) protocol, half-half dilution (HHD) protocol and layered adsorption (LA) protocol were studied and the SERS substrates were monolayer films of 80 nm Ag nanoparticles (NPs) which were modified by polyvinylpyrrolidone. The diffusion/adsorption mechanisms were modelled using the diffusion equation and the electromagnetic field distribution of two adjacent Ag NPs was simulated by the finite-different time-domain method. All experimental data and theoretical analysis suggest that different diffusion/adsorption behaviour of analytes will cause different SERS signal enhancements. HHD protocol could produce the most uniform and reproducible samples, and the corresponding signal intensity of the analyte is the strongest. This study will help to understand and promote the use of SERS technique in quantitative analysis.

Effect of Laser Power on Metallurgical, Mechanical and Tribological Characteristics of Hardfaced Surfaces of Nickel-Based Alloy

NASA Astrophysics Data System (ADS)

Gnanasekaran, S.; Padmanaban, G.; Balasubramanian, V.

2017-12-01

In this present work, nickel based alloy was deposited on 316 LN austenitic stainless steel (ASS) by a laser hardfacing technique to investigate the influence of laser power on macrostructure, microstructure, microhardness, dilution and wear characteristics. The laser power varied from 1.1 to 1.9 kW. The phase constitution, microstructure and microhardness were examined by optical microscope, scanning electron microscopy, energy dispersion spectroscopy and Vickers microhardness tester. The wear characteristics of the hardfaced surfaces and substrate were evaluated at room temperature (RT) under dry sliding wear condition (pin-on-disc). The outcome demonstrates that as the laser power increases, dilution increases and hardness of the deposit decreases. This is because excess heat melts more volume of substrate material and increases the dilution; subsequently it decreases the hardness of the deposit. The microstructure of the deposit is characterized by Ni-rich carbide, boride and silicide.

Spectral radiance measurements and calculated soot concentrations along the length of an experimental combustor

NASA Technical Reports Server (NTRS)

Norgren, C. T.; Ingebo, R. D.

1976-01-01

Radiometric data were obtained over a range of parametric test conditions at three positions along the length of an experimental combustor segment corresponding to the primary, intermediate, and dilution zones. The concentration of soot entrained in the combustion gases was calculated by a technique using spectral radiance measurements. Tests were conducted primarily with Jet A fuel, although limited data were taken with two fuels having higher aromatic content, diesel oil number 2 and a blend of 40 percent tetralin in Jet A fuel. Radiometric observation of the combustion gases indicated that the maximum total radiance peaked at the intermediate zone, which was located immediately upstream of the dilution holes. Soot concentrations calculated from optical measurements in the dilution zone compared favorably with those obtained by in situ gas sampling at the exhaust. The total radiance increased with the higher aromatic content fuels.

Protein Aggregation and Molecular Crowding: Perspectives From Multiscale Simulations.

PubMed

Musiani, F; Giorgetti, A

2017-01-01

Cells are extremely crowded environments, thus the use of diluted salted aqueous solutions containing a single protein is too simplistic to mimic the real situation. Macromolecular crowding might affect protein structure, folding, shape, conformational stability, binding of small molecules, enzymatic activity, interactions with cognate biomolecules, and pathological aggregation. The latter phenomenon typically leads to the formation of amyloid fibrils that are linked to several lethal neurodegenerative diseases, but that can also play a functional role in certain organisms. The majority of molecular simulations performed before the last few years were conducted in diluted solutions and were restricted both in the timescales and in the system dimensions by the available computational resources. In recent years, several computational solutions were developed to get close to physiological conditions. In this review we summarize the main computational techniques used to tackle the issue of protein aggregation both in a diluted and in a crowded environment. © 2017 Elsevier Inc. All rights reserved.

Fe implantation effect in the 6H-SiC semiconductor investigated by Mössbauer spectrometry

NASA Astrophysics Data System (ADS)

Diallo, M. L.; Diallo, L.; Fnidiki, A.; Lechevallier, L.; Cuvilly, F.; Blum, I.; Viret, M.; Marteau, M.; Eyidi, D.; Juraszek, J.; Declémy, A.

2017-08-01

P-doped 6H-SiC substrates were implanted with 57Fe ions at 380 °C or 550 °C to produce a diluted magnetic semiconductor with an Fe homogeneous concentration of about 100 nm thickness. The magnetic properties were studied with 57Fe Conversion Electron Mössbauer Spectrometry at room temperature (RT). Results obtained by this technique on annealed samples prove that ferromagnetism in 57Fe-implanted SiC for Fe concentrations close to 2% and 4% is mostly due to Fe atoms diluted in the matrix. In contrast, for Fe concentrations close to 6%, it also comes from Fe in magnetic phase nano-clusters. This study allows quantifying the Fe amount in the interstitial and substitutional sites and the nanoparticles and shows that the majority of the diluted Fe atoms are substituted on Si sites inducing ferromagnetism up to RT.

Stability and rheology of dilute TiO2-water nanofluids

PubMed Central

2011-01-01

The apparent wall slip (AWS) effect, accompanying the flow of colloidal dispersions in confined geometries, can be an important factor for the applications of nanofluids in heat transfer and microfluidics. In this study, a series of dilute TiO2 aqueous dispersions were prepared and tested for the possible presence of the AWS effect by means of a novel viscometric technique. The nanofluids, prepared from TiO2 rutile or anatase nanopowders by ultrasonic dispersing in water, were stabilized by adjusting the pH to the maximum zeta potential. The resulting stable nanofluid samples were dilute, below 0.7 vol.%. All the samples manifest Newtonian behavior with the fluidities almost unaffected by the presence of the dispersed phase. No case of important slip contribution was detected: the Navier slip coefficient of approximately 2 mm Pa-1 s-1 would affect the apparent fluidity data in a 100-μm gap by less than 1%. PMID:21711783

Spectral-spatial hyperspectral image classification using super-pixel-based spatial pyramid representation

NASA Astrophysics Data System (ADS)

Fan, Jiayuan; Tan, Hui Li; Toomik, Maria; Lu, Shijian

2016-10-01

Spatial pyramid matching has demonstrated its power for image recognition task by pooling features from spatially increasingly fine sub-regions. Motivated by the concept of feature pooling at multiple pyramid levels, we propose a novel spectral-spatial hyperspectral image classification approach using superpixel-based spatial pyramid representation. This technique first generates multiple superpixel maps by decreasing the superpixel number gradually along with the increased spatial regions for labelled samples. By using every superpixel map, sparse representation of pixels within every spatial region is then computed through local max pooling. Finally, features learned from training samples are aggregated and trained by a support vector machine (SVM) classifier. The proposed spectral-spatial hyperspectral image classification technique has been evaluated on two public hyperspectral datasets, including the Indian Pines image containing 16 different agricultural scene categories with a 20m resolution acquired by AVIRIS and the University of Pavia image containing 9 land-use categories with a 1.3m spatial resolution acquired by the ROSIS-03 sensor. Experimental results show significantly improved performance compared with the state-of-the-art works. The major contributions of this proposed technique include (1) a new spectral-spatial classification approach to generate feature representation for hyperspectral image, (2) a complementary yet effective feature pooling approach, i.e. the superpixel-based spatial pyramid representation that is used for the spatial correlation study, (3) evaluation on two public hyperspectral image datasets with superior image classification performance.

In vitro measurement of nucleus pulposus swelling pressure: A new technique for studies of spinal adaptation to gravity

NASA Technical Reports Server (NTRS)

Hargens, A. R.; Glover, M. G.; Mahmood, M. M.; Gott, S.; Garfin, S. R.; Ballard, R.; Murthy, G.; Brown, M. D.

1992-01-01

Swelling of the intervertebral disc nucleus pulposus is altered by posture and gravity. We have designed and tested a new osmometer for in vitro determination of nucleus pulposus swelling pressure. The functional principle of the osmometer involves compressing a sample of nucleus pulposus with nitrogen gas until saline pressure gradients across a 0.45 microns Millipore filter are eliminated. Swelling pressure of both pooled dog and pooled pig lumbar disc nucleus pulposus were measured on the new osmometer and compared to swelling pressures determined using the equilibrium dialysis technique. The osmometer measured swelling pressures comparable to those obtained by the dialysis technique. This osmometer provides a rapid, direct, and accurate measurement of swelling pressure of the nucleus pulposus.

Development of a micromanipulation method for single cell isolation of prokaryotes and its application in food safety.

PubMed

Hohnadel, Marisa; Maumy, Myriam; Chollet, Renaud

2018-01-01

For nearly a century, conventional microbiological methods have been standard practice for detecting and identifying pathogens in food. Nevertheless, the microbiological safety of food has improved and various rapid methods have been developed to overcome the limitations of conventional methods. Alternative methods are expected to detect low cell numbers, since the presence in food of even a single cell of a pathogenic organism may be infectious. With respect to low population levels, the performance of a detection method is assessed by producing serial dilutions of a pure bacterial suspension to inoculate representative food matrices with highly diluted bacterial cells (fewer than 10 CFU/ml). The accuracy of data obtained by multiple dilution techniques is not certain and does not exclude some colonies arising from clumps of cells. Micromanipulation techniques to capture and isolate single cells from environmental samples were introduced more than 40 years ago. The main limitation of the current micromanipulation technique is still the low recovery rate for the growth of a single cell in culture medium. In this study, we describe a new single cell isolation method and demonstrate that it can be used successfully to grow various types of microorganism from picked individual cells. Tests with Gram-positive and Gram-negative organisms, including cocci, rods, aerobes, anaerobes, yeasts and molds showed growth recovery rates from 60% to 100% after micromanipulation. We also highlight the use of our method to evaluate and challenge the detection limits of standard detection methods in food samples contaminated by a single cell of Salmonella enterica.

REDUCING CHILDREN'S RISK FROM LEAD IN SOIL

EPA Science Inventory

Traditional methods for reducing risk from elevated levels of soil Pb involves removal, covering, or dilution by mixing with uncontaminated soil. Believing that in situ remediation techniques are viable alternatives, the EPA=s National Risk Management Research Laboratory (NRMRL) ...

Multi-laboratory survey of qPCR enterococci analysis method performance

EPA Pesticide Factsheets

Quantitative polymerase chain reaction (qPCR) has become a frequently used technique for quantifying enterococci in recreational surface waters, but there are several methodological options. Here we evaluated how three method permutations, type of mastermix, sample extract dilution and use of controls in results calculation, affect method reliability among multiple laboratories with respect to sample interference. Multiple samples from each of 22 sites representing an array of habitat types were analyzed using EPA Method 1611 and 1609 reagents with full strength and five-fold diluted extracts. The presence of interference was assessed three ways: using sample processing and PCR amplifications controls; consistency of results across extract dilutions; and relative recovery of target genes from spiked enterococci in water sample compared to control matrices with acceptable recovery defined as 50 to 200%. Method 1609, which is based on an environmental mastermix, was found to be superior to Method 1611, which is based on a universal mastermix. Method 1611 had over a 40% control assay failure rate with undiluted extracts and a 6% failure rate with diluted extracts. Method 1609 failed in only 11% and 3% of undiluted and diluted extracts analyses. Use of sample processing control assay results in the delta-delta Ct method for calculating relative target gene recoveries increased the number of acceptable recovery results. Delta-delta tended to bias recoveries fr

Determination of low-level (sub-microgram) sulfur concentrations by isotope dilution multi-collector inductively couple plasma mass spectrometry using a 33S spike and internal normalization for mass bias correction.

PubMed

Mann, Jacqueline L; Vocke, Robert D; Kelly, W Robert

2012-05-30

The certification of sulfur (S) in Standard Reference Materials™ by the National Institute of Standards and Technology (NIST) has been exclusively performed using isotope dilution thermal ionization mass spectrometry (ID-TIMS). The ID-TIMS measurement method is limited in its capability for low concentration measurements (<1 µg/g) due to the blank associated with the chemical reduction procedure (≈0.2 S µg). Newly developed materials and applications, such as biofuels made from soy and nanomedicine, pose a challenge to the ID-TIMS technique because of their very low concentrations (<1 µg/g) of S. As described here, a measurement technique with low S blanks is essential for low-level S measurements. An isotope dilution (ID) multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) method combined with an internal normalization approach for mass bias correction has been used to determine low-level S concentrations in synthetically prepared mixtures using a (33)S-enriched spike material. Dilute sulfur solutions (1 µg S/g) were prepared from NIST SRM 3154 (Sulfate Spectrometric Solution) to test the capability of this technique for measuring very low-level S concentrations. The concentration results for each solution were 0.983 ± 0.004 µg/g (95% CI, n = 2, k = 2), 1.006 ± 0.005 µg/g (95% CI, n = 2, k = 2), and 0.999 ± 0.003 µg/g (95% CI, n = 2, k = 2), in excellent agreement with the gravimetric determination, deviating less than 0.35% and suggesting the technique can yield unbiased and accurate results. The blanks averaged 13 ± 0.0017 ng S (1s). The data results provide a clear indication that the ID-MC-ICP-MS method for the determination of low-level S concentrations is feasible. The more than one order of magnitude reduction of the blanks suggests that it is a better alternative to the ID-TIMS method for very low S materials such as are encountered in biofuels and some biochemical species. Published 2012. This article is a US Government work and is in the public domain in the USA. Published 2012. This article is a US Government work and is in the public domain in the USA.

Isotropic in-plane quenched disorder and dilution induce a robust nematic state in electron-doped pnictides

DOE PAGES

Liang, Shuhua; Bishop, Christopher B.; Moreo, Adriana; ...

2015-09-21

The phase diagram of electron-doped pnictides is studied varying the temperature, electronic density, and isotropic in-plane quenched disorder strength and dilution by means of computational techniques applied to a three-orbital (xz,yz,xy) spin-fermion model with lattice degrees of freedom. In experiments, chemical doping introduces disorder but in theoretical studies the relationship between electronic doping and the randomly located dopants, with their associated quenched disorder, is difficult to address. Moreover, in this publication, the use of computational techniques allows us to study independently the effects of electronic doping, regulated by a global chemical potential, and impurity disorder at randomly selected sites. Surprisingly,more » our Monte Carlo simulations reveal that the fast reduction with doping of the N eel T N and the structural T S transition temperatures, and the concomitant stabilization of a robust nematic state, is primarily controlled in our model by the magnetic dilution associated with the in-plane isotropic disorder introduced by Fe substitution. In the doping range studied, changes in the Fermi surface produced by electron doping affect only slightly both critical temperatures. Our results also suggest that the specific material-dependent phase diagrams experimentally observed could be explained as a consequence of the variation in disorder profiles introduced by the different dopants. Finally, our findings are also compatible with neutron scattering and scanning tunneling microscopy, unveiling a patchy network of locally magnetically ordered clusters with anisotropic shapes, even though the quenched disorder is locally isotropic. Our study reveals a remarkable and unexpected degree of complexity in pnictides: the fragile tendency to nematicity intrinsic of translational invariant electronic systems needs to be supplemented by quenched disorder and dilution to stabilize the robust nematic phase experimentally found in electron-doped 122 compounds.« less

Isotropic in-plane quenched disorder and dilution induce a robust nematic state in electron-doped pnictides

NASA Astrophysics Data System (ADS)

Liang, Shuhua; Bishop, Christopher B.; Moreo, Adriana; Dagotto, Elbio

2015-09-01

The phase diagram of electron-doped pnictides is studied varying the temperature, electronic density, and isotropic in-plane quenched disorder strength and dilution by means of computational techniques applied to a three-orbital (x z ,y z ,x y ) spin-fermion model with lattice degrees of freedom. In experiments, chemical doping introduces disorder but in theoretical studies the relationship between electronic doping and the randomly located dopants, with their associated quenched disorder, is difficult to address. In this publication, the use of computational techniques allows us to study independently the effects of electronic doping, regulated by a global chemical potential, and impurity disorder at randomly selected sites. Surprisingly, our Monte Carlo simulations reveal that the fast reduction with doping of the Néel TN and the structural TS transition temperatures, and the concomitant stabilization of a robust nematic state, is primarily controlled in our model by the magnetic dilution associated with the in-plane isotropic disorder introduced by Fe substitution. In the doping range studied, changes in the Fermi surface produced by electron doping affect only slightly both critical temperatures. Our results also suggest that the specific material-dependent phase diagrams experimentally observed could be explained as a consequence of the variation in disorder profiles introduced by the different dopants. Our findings are also compatible with neutron scattering and scanning tunneling microscopy, unveiling a patchy network of locally magnetically ordered clusters with anisotropic shapes, even though the quenched disorder is locally isotropic. This study reveals a remarkable and unexpected degree of complexity in pnictides: the fragile tendency to nematicity intrinsic of translational invariant electronic systems needs to be supplemented by quenched disorder and dilution to stabilize the robust nematic phase experimentally found in electron-doped 122 compounds.

Improving viability of cryopreserved honey bee (Apis mellifera L.) sperm with selected diluents, cryoprotectants, and semen dilution ratios.

PubMed

Taylor, M A; Guzmán-Novoa, E; Morfin, N; Buhr, M M

2009-07-15

This is the first study where the systematic application of theories and techniques used in mammalian sperm cryopreservation have been applied to honey bee (Apis mellifera L.) semen as a means to improve postthaw viability of cryopreserved sperm. Six newly designed diluents, three cryoprotectants (dimethyl sulfoxide, DMA, glycerol), and five diluent:semen ratios (1:1, 3:1, 6:1, 9:1, and 12:1) were tested. In addition, the sperm freezing tolerance of three honey bee strains was evaluated. Specific protocols were designed to control semen freezing and thawing rates. Sperm motility was assessed visually, whereas sperm viability was assessed using SYBR-14 and propidium iodide fluorescent stains. Diluent treatments did not affect fresh (nonfrozen) sperm viability yet affected fresh sperm motility (P<0.05). Based on these assessments, two diluents were chosen and used in all successive cryopreservation experiments. Using the selected diluents, semen was collected at various diluent:semen ratios, along with one of the three cryoprotectants. Semen collected at high dilution ratios, using a hypotonic antioxidant diluent containing catalase, in combination with dimethyl sulfoxide, provided higher postthaw sperm viability than that of all other combinations tested (68.3+/-5.4%; P<0.05). Using this combination of dilution ratio, diluent, and cryoprotectant, there were no differences among honey bee strains for postthaw sperm viability (P=0.805). Nevertheless, these new semen dilution and freezing methods improved postthaw viability of sperm to levels that could theoretically sustain worker populations in colonies, thus providing potential for further optimization of cryopreservation techniques for the genetic preservation and improvement of honey bee genotypes.

Committee on Diabetes Mellitus Indices of the Japan Society of Clinical Chemistry-recommended reference measurement procedure and reference materials for glycated albumin determination.

PubMed

Takei, Izumi; Hoshino, Tadao; Tominaga, Makoto; Ishibashi, Midori; Kuwa, Katsuhiko; Umemoto, Masao; Tani, Wataru; Okahashi, Mikiko; Yasukawa, Keiko; Kohzuma, Takuji; Sato, Asako

2016-01-01

Glycated albumin is an intermediate glycaemic control marker for which there are several measurement procedures with entirely different reference intervals. We have developed a reference measurement procedure for the purpose of standardizing glycated albumin measurements. The isotope dilution liquid chromatography/tandem mass spectrometry method was developed as a reference measurement procedure for glycated albumin. The stable isotopes of lysine and fructosyl-lysine, which serve as an internal standard, were added to albumin isolated from serum, followed by hydrogenation. After hydrolysis of albumin with hot hydrochloric acid, the liberated lysine and fructosyl-lysine were measured by liquid chromatography/tandem mass spectrometry, and their concentrations were determined from each isotope ratio. The reference materials (JCCRM611) for determining of glycated albumin were prepared from pooled patient blood samples. The isotope dilution-tandem mass spectrometry calibration curve of fructosyl-lysine and lysine showed good linearity (r = 0.999). The inter-assay and intra-assay coefficient of variation values of glycated albumin measurement were 1.2 and 1.4%, respectively. The glycated albumin values of serum in patients with diabetes assessed through the use of this method showed a good relationship with routine measurement procedures (r = 0.997). The relationship of glycated albumin values of the reference material (JCCRM611) between these two methods was the same as the relationship with the patient serum samples. The Committee on Diabetes Mellitus Indices of the Japan Society of Clinical Chemistry recommends the isotope dilution liquid chromatography/tandem mass spectrometry method as a reference measurement procedure, and JCCRM611 as a certified reference material for glycated albumin measurement. In addition, we recommend the traceability system for glycated albumin measurement. © The Author(s) 2015.

A biogeochemical comparison of two well-buffered catchments with contrasting histories of acid deposition

USGS Publications Warehouse

Shanley, J.B.; Kram, P.; Hruska, J.; Bullen, T.D.

2004-01-01

Much of the biogeochemical cycling research in catchments in the past 25 years has been driven by acid deposition research funding. This research has focused on vulnerable base-poor systems; catchments on alkaline lithologies have received little attention. In regions of high acid loadings, however, even well-buffered catchments are susceptible to forest decline and episodes of low alkalinity in streamwater. As part of a collaboration between the Czech and U.S. Geological Surveys, we compared biogeochemical patterns in two well-studied, well-buffered catchments: Pluhuv Bor in the western Czech Republic, which has received high loading of atmospheric acidity, and Sleepers River Research Watershed in Vermont, U.S.A., where acid loading has been considerably less. Despite differences in lithology, wetness, forest type, and glacial history, the catchments displayed similar patterns of solute concentrations and flow. At both catchments, base cation and alkalinity diluted with increasing flow, whereas nitrate and dissolved organic carbon increased with increasing flow. Sulfate diluted with increasing flow at Sleepers River, while at Pluhuv Bor the sulfate-flow relation shifted from positive to negative as atmospheric sulfur (S) loadings decreased and soil S pools were depleted during the 1990s. At high flow, alkalinity decreased to near 100 ??eq L-1 at Pluhuv Bor compared to 400 ??eq L-1 at Sleepers River. Despite the large amounts of S flushed from Pluhuv Bor soils, these alkalinity declines were caused solely by dilution, which was greater at Pluhuv Bor relative to Sleepers River due to greater contributions from shallow flow paths at high flow. Although the historical high S loading at Pluhuv Bor has caused soil acidification and possible forest damage, it has had little effect on the acid/base status of streamwater in this well-buffered catchment. ?? 2004 Kluwer Academic Publishers.

[Growth of Clostridium botulinum in media with garlic (Allium sativum)].

PubMed

Giménez, M A; Solanes, R E; Giménez, D F

1988-01-01

The effect of garlic on the growth and toxin formation of Clostridium botulinum (GT) was studied in A) crude juice obtained from a pool of cloves by i) crushing, ii) pressing out and iii) filtration, and B) minced garlic (6 to 8 pieces per clove). For both, "white" and "red" garlic varieties were used. The juice (pH 5.7 to 6.0, for different batches) was activated 30 min at 37 degrees C and diluted (log 2) in PGY broth (g%: peptone (Difco) 1.0; glucose 0.5; yeast extract (Difco) 0.5; pH 7.3). A small drop from a 18 h at 37 degrees C chopped meat medium culture of a highly toxigenic autochthonous strain (110) of C. botulinum type A, was transferred to the juice dilutions, incubating anaerobically 15d at 37 degrees C. As a control of the inhibitory effect of the juice, four microorganisms were cultured 48 h at 37 degrees C in the juice dilutions (Table 1). Clove pieces were suspended to 50% (w/v) either in PGY broth or distilled water without pH adjustment. Aliquots were heated in water bath 15 min at 100 degrees C. After seeded with the A 110 strain, duplicate tubes and their controls were incubated 15 d at 37 degrees C in aerated and anaerobic conditions (Table 2). Titers of botulinum toxin were empirically estimated by the time to death of a pair of mice injected with 0.5 ml each, via IP, observed 72 h. Results are shown in tables 1 and 2. Garlic reduces (in undiluted juice, traces or 3 to 5 DL50/ml were recorded in separate experiments) but not inhibit GT.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryopreservation of Indian red jungle fowl (Gallus gallus murghi) semen with polyvinylpyrrolidone.

PubMed

Rakha, Bushra Allah; Ansari, Muhammad Sajjad; Akhter, Shamim; Zafar, Zartasha; Hussain, Iftikhar; Santiago-Moreno, Julian; Blesbois, Elisabeth

2017-10-01

The Indian red jungle fowl is a sub-species of the genus Gallus native to South Asia; facing high risk of extinction in its native habitat. During cryopreservation, permeable cryoprotectants like glycerol are usually employed and we previously showed encouraging results with 20% glycerol. Because bird spermatozoa contain very little intracellular water, the possibility of replacing an internal cryoprotectant by an external one is opened. In the present study, we tested the replacement of internal cryoprotectant glycerol by the external cryoprotectant Polyvinylpyrrolidone (PVP). PVP is a non-permeable cryoprotectant and keeps the sperm in glassy state both in cooling and warming stages without making ice crystallization within the sperm cell. We evaluated the effect of various levels of polyvinylpyrrolidone (PVP) on Indian red jungle fowl semen quality and fertility outcomes. The qualifying semen ejaculates collected from eight mature cocks were pooled, divided into five aliquots, diluted (37 °C) with red fowl semen extender having PVP [0% (control) 4% (w/v), 6% (w/v), 8% (w/v) and 10% (w/v)]. Diluted semen was cryopreserved and stored in liquid nitrogen. The whole experiment was repeated/replicated for five times independently. Sperm motility, plasma membrane integrity, viability and acrosome integrity were recorded highest (P < 0.05) with 6% PVP at post-dilution, cooling, equilibration and freeze-thawing. Higher (P < 0.05) no. of fertile eggs, fertility, no. of hatched chicks, percent hatch and hatchability was recorded with 6% PVP compared to control. It is concluded that 6% PVP maintained better post-taw quality and fertility of Indian red jungle fowl spermatozoa than glycerol and can be used in routine practice avoiding the contraceptive effects of glycerol. Copyright © 2017 Elsevier Inc. All rights reserved.

Acetate scavenging activity in Escherichia coli: interplay of acetyl-CoA synthetase and the PEP-glyoxylate cycle in chemostat cultures.

PubMed

Renilla, Sergio; Bernal, Vicente; Fuhrer, Tobias; Castaño-Cerezo, Sara; Pastor, José M; Iborra, José L; Sauer, Uwe; Cánovas, Manuel

2012-03-01

Impairment of acetate production in Escherichia coli is crucial for the performance of many biotechnological processes. Aerobic production of acetate (or acetate overflow) results from changes in the expression of central metabolism genes. Acetyl-CoA synthetase scavenges extracellular acetate in glucose-limited cultures. Once converted to acetyl-CoA, it can be catabolized by the tricarboxylic acid cycle or the glyoxylate pathway. In this work, we assessed the significance of these pathways on acetate overflow during glucose excess and limitation. Gene expression, enzyme activities, and metabolic fluxes were studied in E. coli knock-out mutants related to the glyoxylate pathway operon and its regulators. The relevance of post-translational regulation by AceK-mediated phosphorylation of isocitrate dehydrogenase for pathway functionality was underlined. In chemostat cultures performed at increasing dilution rates, acetate overflow occurs when growing over a threshold glucose uptake rate. This threshold was not affected in a glyoxylate-pathway-deficient strain (lacking isocitrate lyase, the first enzyme of the pathway), indicating that it is not relevant for acetate overflow. In carbon-limited chemostat cultures, gluconeogenesis (maeB, sfcA, and pck), the glyoxylate operon and, especially, acetyl-CoA synthetase are upregulated. A mutant in acs (encoding acetyl-CoA synthetase) produced acetate at all dilution rates. This work demonstrates that, in E. coli, acetate production occurs at all dilution rates and that overflow is the result of unbalanced synthesis and scavenging activities. The over-expression of acetyl-CoA synthetase by cAMP-CRP-dependent induction limits this phenomenon in cultures consuming glucose at low rate, ensuring the recycling of the acetyl-CoA and acetyl-phosphate pools, although establishing an energy-dissipating substrate cycle.

Simultaneous Quantification of Free Cholesterol, Cholesteryl Esters, and Triglycerides without Ester Hydrolysis by UHPLC Separation and In-Source Collision Induced Dissociation Coupled MS/MS

NASA Astrophysics Data System (ADS)

Gardner, Michael S.; McWilliams, Lisa G.; Jones, Jeffrey I.; Kuklenyik, Zsuzsanna; Pirkle, James L.; Barr, John R.

2017-08-01

We demonstrate the application of in-source nitrogen collision-induced dissociation (CID) that eliminates the need for ester hydrolysis before simultaneous analysis of esterified cholesterol (EC) and triglycerides (TG) along with free cholesterol (FC) from human serum, using normal phase liquid chromatography (LC) coupled to atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (MS/MS). The analysis requires only 50 μL of 1:100 dilute serum with a high-throughput, precipitation/evaporation/extraction protocol in one pot. Known representative mixtures of EC and TG species were used as calibrators with stable isotope labeled analogs as internal standards. The APCI MS source was operated with nitrogen source gas. Reproducible in-source CID was achieved with the use of optimal cone voltage (declustering potential), generating FC, EC, and TG lipid class-specific precursor fragment ions for multiple reaction monitoring (MRM). Using a representative mixture of purified FC, CE, and TG species as calibrators, the method accuracy was assessed with analysis of five inter-laboratory standardization materials, showing -10% bias for Total-C and -3% for Total-TG. Repeated duplicate analysis of a quality control pool showed intra-day and inter-day variation of 5% and 5.8% for FC, 5.2% and 8.5% for Total-C, and 4.1% and 7.7% for Total-TG. The applicability of the method was demonstrated on 32 serum samples and corresponding lipoprotein sub-fractions collected from normolipidemic, hypercholesterolemic, hypertriglyceridemic, and hyperlipidemic donors. The results show that in-source CID coupled with isotope dilution UHPLC-MS/MS is a viable high precision approach for translational research studies where samples are substantially diluted or the amounts of archived samples are limited. [Figure not available: see fulltext.

[Asthma caused by Lucilia Caesar larvae: clinical and immunologic study].

PubMed

Siracusa, A; Verga, A; Bacoccoli, R; Fabbri, A; Felicioni, D

1989-01-01

Lucilia Caesar larvae (LCL) are used as live fish bait by anglers. Five cases of asthma and rhinoconjunctivitis following exposure to LCL are reported. Three had work-related asthma as they were working on a fish bait farm or shop and two had asthma when they went fishing. In one subject exposure to LCL caused asthma, rhinoconjunctivitis and contact urticaria. In four subjects peak expiratory flow rate (PEFR) was monitored during exposure to LCL. In three out of four subjects there was evidence of LCL-related asthma. In one subject it was not possible to record PEFR during exposure to LCL, as he had not gone fishing since 1985. Two extracts of LCL were prepared: one was the PBS (phosphate-buffered saline) washing fluid of LCL, the other was the PBS extract of homogenized LCL. Positive cutaneous prick tests to both LCL extracts were detected in three out of four symptomatic subjects. Specific IgE against both LCL extract antigens were found by the RAST method in four out of five subjects with LCL-related asthma. One subject had both negative skin tests and RAST. Specificity and potency of LCL-IgE binding was shown by RAST inhibition method performed on the serum pool of four patients with positive RAST results. Significant inhibition of more than 50% by LCL washing fluid at a dilution extract was found at a dilution of 1:10 and by homogenized LCL extract at a dilution of 1:100. No significant inhibition of LCL-IgE binding by dermatophagoides, parietaria and milk antigens was found. This study demonstrated that LCL emanations are potent sensitizers and elicit IgE-mediated asthma.

Eco-engineered rock pools: a concrete solution to biodiversity loss and urban sprawl in the marine environment

NASA Astrophysics Data System (ADS)

Firth, Louise B.; Browne, Keith A.; Knights, Antony M.; Hawkins, Stephen J.; Nash, Róisín

2016-09-01

In coastal habitats artificial structures typically support lower biodiversity and can support greater numbers of non-native and opportunistic species than natural rocky reefs. Eco-engineering experiments are typically trialed to succeed; but arguably as much is learnt from failure than from success. Our goal was to trial a generic, cost effective, eco-engineering technique that could be incorporated into rock armouring anywhere in the world. Artificial rock pools were created from manipulated concrete between boulders on the exposed and sheltered sides of a causeway. Experimental treatments were installed in locations where they were expected to fail and compared to controls installed in locations in which they were expected to succeed. Control pools were created lower on the structure where they were immersed on every tidal cycle; experimental pools were created above mean high water spring tide which were only immersed on spring tides. We hypothesised that lower and exposed pools would support significantly higher taxon and functional diversity than upper and sheltered pools. The concrete pools survived the severe winter storms of 2013/14. After 12 months, non-destructive sampling revealed significantly higher mean taxon and functional richness in lower pools than upper pools on the exposed side only. After 24 months the sheltered pools had become inundated with sediments, thus failing to function as rock pools as intended. Destructive sampling on the exposed side revealed significantly higher mean functional richness in lower than upper pools. However, a surprisingly high number of taxa colonised the upper pools leading to no significant difference in mean taxon richness among shore heights. A high number of rare taxa in the lower pools led to total taxon richness being almost twice that of upper pools. These findings highlight that even when expected to fail concrete pools supported diverse assemblages, thus representing an affordable, replicable means of enhancing biodiversity on a variety of artificial structures.

A Comparison of Item Selection Techniques and Exposure Control Mechanisms in CATs Using the Generalized Partial Credit Model.

ERIC Educational Resources Information Center

Pastor, Dena A.; Dodd, Barbara G.; Chang, Hua-Hua

2002-01-01

Studied the impact of using five different exposure control algorithms in two sizes of item pool calibrated using the generalized partial credit model. Simulation results show that the a-stratified design, in comparison to a no-exposure control condition, could be used to reduce item exposure and overlap and increase pool use, while degrading…

Vitamin B12 absorption judged by measurement of holotranscobalamin, active vitamin B12: evaluation of a commercially available EIA kit.

PubMed

Greibe, Eva; Nexo, Ebba

2011-11-01

Active vitamin B12 absorption is followed by an increase in holotranscobalamin (holoTC) upon loading with a high physiological dose of the vitamin (the CobaSorb test). This study evaluates the use of a newly launched EIA kit for measurement of holoTC (active B12) in relation to the CobaSorb test. Intra-assay imprecision and linearity of the EIA kit was examined, employing serum pools of increasing holoTC concentrations. For the CobaSorb test, holoTC was measured before and after loading with 3-times 9 μg of vitamin B12 employing both the in-house ELISA and the EIA kit (n=25). The EIA kit showed an intra-assay CV between 2.2% and 5.8% for holoTC values ranging from 21 to 80 pmol/L. Employing diluted serum samples resulted in spurious high values of holoTC. The EIA kit performed well in relation to the CobaSorb test and classified the patients studied as capable of absorbing vitamin B12 (n=10) or not (n=15), as did the in-house ELISA. The Active B12 (holoTC) EIA kit proved suitable for use with the CobaSorb test, but not for analysis of diluted serum samples.

Fungal inoculation and elevated CO2 mediate growth of Lolium mutiforum and Phytolacca americana, metal uptake, and metal bioavailability in metal-contaminated soil: evidence from DGT measurement.

PubMed

Song, Ningning; Wang, Fangli; Zhang, Changbo; Tang, Shirong; Guo, Junkang; Ju, Xuehai; Smith, Donald L

2013-01-01

Fungal inoculation and elevated CO2 may mediate plant growth and uptake of heavy metals, but little evidence from Diffusive Gradients in Thin-films (DGT) measurement has been obtained to characterize the process. Lolium mutiforum and Phytolacca americana were grown at ambient and elevated CO2 on naturally Cd and Pb contaminated soils inoculated with and without Trichoderma asperellum strain C3 or Penicillium chrysogenum strain D4, to investigate plant growth, metal uptake, and metal bioavailability responses. Fungal inoculation increased plant biomass and shoot/root Cd and Pb concentrations. Elevated CO2 significantly increased plants biomass, but decreased Cd and Pb concentrations in shoot/root to various extents, leading to a metal dilution phenomenon. Total Cd and Pb uptake by plants, and DGT-measured Cd and Pb concentrations in rhizosphere soils, were higher in all fungal inoculation and elevated CO2 treatments than control treatments, with the combined treatments having more influence than either treatment alone. Metal dilution phenomenon occurred because the increase in DGT-measured bioavailable metal pools in plant rhizosphere due to elevated CO2 was unable to match the increase in requirement for plant uptake of metals due to plant biomass increase.

Quantification of four major metabolites of embryotoxic N-methyl- and N-ethyl-2-pyrrolidone in human urine by cooled-injection gas chromatography and isotope dilution mass spectrometry.

PubMed

Schindler, Birgit K; Koslitz, Stephan; Meier, Swetlana; Belov, Vladimir N; Koch, Holger M; Weiss, Tobias; Brüning, Thomas; Käfferlein, Heiko U

2012-04-17

N-Methyl- and N-ethyl-2-pyrollidone (NMP and NEP) are frequently used industrial solvents and were shown to be embryotoxic in animal experiments. We developed a sensitive, specific, and robust analytical method based on cooled-injection (CIS) gas chromatography and isotope dilution mass spectrometry to analyze 5-hydroxy-N-ethyl-2-pyrrolidone (5-HNEP) and 2-hydroxy-N-ethylsuccinimide (2-HESI), two newly identified presumed metabolites of NEP, and their corresponding methyl counterparts (5-HNMP, 2-HMSI) in human urine. The urine was spiked with deuterium-labeled analogues of these metabolites. The analytes were separated from urinary matrix by solid-phase extraction and silylated prior to quantification. Validation of this method was carried out by using both, spiked pooled urine samples and urine samples from 56 individuals of the general population with no known occupational exposure to NMP and NEP. Interday and intraday imprecision was better than 8% for all metabolites, while the limits of detection were between 5 and 20 μg/L depending on the analyte. The high sensitivity of the method enables us to quantify NMP and NEP metabolites at current environmental exposures by human biomonitoring.

Nuclear pool of phosphatidylinositol 4 phosphate 5 kinase 1α is modified by polySUMO-2 during apoptosis.

PubMed

Chakrabarti, Rajarshi; Bhowmick, Debajit; Bhargava, Varsha; Bhar, Kaushik; Siddhanta, Anirban

2013-09-20

Phosphatidylinositol 4 phosphate 5 kinase 1α (PIP5K) is mainly localized in the cytosol and plasma membrane. Studies have also indicated its prominent association with nuclear speckles. The exact nature of this nuclear pool of PIP5K is not clear. Using biochemical and microscopic techniques, we have demonstrated that the nuclear pool of PIP5K is modified by SUMO-1 in HEK-293 cells stably expressing PIP5K. Moreover, this SUMOylated pool of PIP5K increased during apoptosis. PolySUMO-2 chain conjugated PIP5K was detected by pull-down experiment using affinity-tagged RNF4, a polySUMO-2 binding protein, during late apoptosis. Copyright © 2013 Elsevier Inc. All rights reserved.

Endoscopic needle-knife treatment for symptomatic esophageal Zenker's diverticulum: A meta-analysis and systematic review.

PubMed

Li, Lian Yong; Yang, Yong Tao; Qu, Chang Min; Liang, Shu Wen; Zhong, Chang Qing; Wang, Xiao Ying; Chen, Yan; Spandorfer, Robert M; Christofaro, Sarah; Cai, Qiang

2018-04-01

The aim of this study was to assess the efficacy and safety following endoscopic management of Zenker's diverticulum (ZD) using a needle-knife technique. A systematic search of PubMed, Embase and Cochrane library databases was performed. All original studies reporting efficacy and safety of needle-knife technique for treatment of ZD were included. Pooled event rates across studies were expressed with summative statistics. Main outcomes, such as rates of immediate symptomatic response (ISR), adverse events and recurrence, were extracted, pooled and analyzed. Heterogeneity among studies was assessed using the R statistic. The random effects model was used and results were expressed with forest plots and summative statistics. Thirteen studies included 589 patients were enrolled. Pooled event rates for ISR, overall complication, bleeding and perforation were 88% (95% confidence interval [CI] 79-94%), 13% (95% CI 8-22%), 5% (95% CI 3-10%) and 7% (95% CI 4-12%), respectively. The pooled data demonstrated an overall recurrence rate of 14% (95% CI 9-21%). Diverticulum size of at least 4 cm and less than 4 cm demonstrated pooled adverse event rates of 17% (95% CI 10-27%) and 7% (95% CI 2-18%), respectively. When using diverticuloscope as an accessory, pooled ISR and adverse events rates were 84% (95% CI 58-95%) and 10% (95% CI 3-26%), respectively. Flexible endoscopic procedures using needle-knife offers a relatively safe and effective treatment of symptomatic ZD, especially for ZD of <4 cm in diameter. © 2018 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

Evaluation of different selective media and culturing techniques for the quantification of Campylobacter ssp. from broiler litter.

PubMed

Kiess, A S; Parker, H M; McDaniel, C D

2010-08-01

Poultry is a major reservoir for Campylobacter, the leading cause of foodborne illness in the United States, but how broilers become initially colonized is still under debate. Broiler litter is a potential source, but the best technique for quantifying Campylobacter from litter is still unknown. Therefore, our objectives were to determine if certain media are more selective for quantifying Campylobacter and if enrichment allows for the detection of stressed or viable but nonculturable cells from broiler litter samples. In this trial, 5 media and 2 culturing techniques were used to enumerate Campylobacter from broiler litter. The media used were campy-Line agar (CLA), campy-cefex agar (CCA), modified CCA, Campylobacter agar plates (CAP), and modified charcoal cefoperazone deoxycholate agar. Litter samples were obtained from a commercial broiler house. Each sample was equally divided and diluted 10-fold into peptone, for direct plating, or 4-fold into Campylobacter enrichment broth. Samples diluted in peptone were direct-plated onto each media and incubated under microaerophilic conditions for 48 h at 42 degrees C. Samples diluted in enrichment broth were incubated under the same conditions for 24 h, then further diluted to 10-fold before plating. Plates from enriched samples were incubated for an additional 24 h after plating. After incubation, all plates (direct and enriched) were counted and presumptive positive colonies were confirmed using a Campylobacter latex agglutination kit. Results indicated that there was no difference in the ability of any of the selective media tested to grow Campylobacter. Direct-plated samples had a higher Campylobacter isolation rate compared with enriched samples. The CLA and CAP were able to suppress total bacterial growth better than modified charcoal cefoperazone deoxycholate, modified CCA, and CCA. The CLA and CAP were the only media able to detect total bacterial population shifts over time. In conclusion, it is important before making a final decision on a selective medium to consider the medium's ability to suppress total bacterial growth as well as isolate Campylobacter.

Measurement of isotope abundance variations in nature by gravimetric spiking isotope dilution analysis (GS-IDA).

PubMed

Chew, Gina; Walczyk, Thomas

2013-04-02

Subtle variations in the isotopic composition of elements carry unique information about physical and chemical processes in nature and are now exploited widely in diverse areas of research. Reliable measurement of natural isotope abundance variations is among the biggest challenges in inorganic mass spectrometry as they are highly sensitive to methodological bias. For decades, double spiking of the sample with a mix of two stable isotopes has been considered the reference technique for measuring such variations both by multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) and multicollector-thermal ionization mass spectrometry (MC-TIMS). However, this technique can only be applied to elements having at least four stable isotopes. Here we present a novel approach that requires measurement of three isotope signals only and which is more robust than the conventional double spiking technique. This became possible by gravimetric mixing of the sample with an isotopic spike in different proportions and by applying principles of isotope dilution for data analysis (GS-IDA). The potential and principle use of the technique is demonstrated for Mg in human urine using MC-TIMS for isotopic analysis. Mg is an element inaccessible to double spiking methods as it consists of three stable isotopes only and shows great potential for metabolically induced isotope effects waiting to be explored.

Classification of Alzheimer's Disease Based on Eight-Layer Convolutional Neural Network with Leaky Rectified Linear Unit and Max Pooling.

PubMed

Wang, Shui-Hua; Phillips, Preetha; Sui, Yuxiu; Liu, Bin; Yang, Ming; Cheng, Hong

2018-03-26

Alzheimer's disease (AD) is a progressive brain disease. The goal of this study is to provide a new computer-vision based technique to detect it in an efficient way. The brain-imaging data of 98 AD patients and 98 healthy controls was collected using data augmentation method. Then, convolutional neural network (CNN) was used, CNN is the most successful tool in deep learning. An 8-layer CNN was created with optimal structure obtained by experiences. Three activation functions (AFs): sigmoid, rectified linear unit (ReLU), and leaky ReLU. The three pooling-functions were also tested: average pooling, max pooling, and stochastic pooling. The numerical experiments demonstrated that leaky ReLU and max pooling gave the greatest result in terms of performance. It achieved a sensitivity of 97.96%, a specificity of 97.35%, and an accuracy of 97.65%, respectively. In addition, the proposed approach was compared with eight state-of-the-art approaches. The method increased the classification accuracy by approximately 5% compared to state-of-the-art methods.

STORM-SEWER FLOW MEASUREMENT AND RECORDING SYSTEM.

USGS Publications Warehouse

Kilpatrick, Frederick A.; Kaehrle, William R.

1986-01-01

A comprehensive study and development of instruments and techniques for measuring all components of flow in a storm-sewer drainage system were undertaken by the U. S. Geological Survey under the sponsorship of FHWA. The study involved laboratory and field calibration and testing of measuring flumes, pipe insert meters, weirs, and electromagnetic velocity meters as well as the development and calibration of pneumatic bubbler and pressure transducer head-measuring systems. Tracer dilution and acoustic-flowmeter measurements were used in field verification tests. A single micrologger was used to record data from all the instruments and also to activate on command the electromagnetic velocity meter and tracer dilution systems.

Investigation of effects of background water on upwelled reflectance spectra and techniques for analysis of dilute primary-treated sewage sludge

NASA Technical Reports Server (NTRS)

Whitlock, C. H.; Usry, J. W.; Witte, W. G.; Farmer, F. H.; Gurganus, E. A.

1979-01-01

In an effort to improve understanding of the effects of variations in background water on reflectance spectra, laboratory tests were conducted with various concentrations of sewage sludge diluted with several types of background water. The results from these tests indicate that reflectance spectra for sewage-sludge mixtures are dependent upon the reflectance of the background water. Both the ratio of sewage-sludge reflectance to background-water reflectance and the ratio of the difference in reflectance to background-water reflectance show spectral variations for different turbid background waters. The difference in reflectance is the only parameter considered.

Metallic Hydrogen - Potentially a High Energy Rocket Propellant

NASA Technical Reports Server (NTRS)

Cole, John; Silvera, Ike

2007-01-01

Pure metallic hydrogen is predicted to have a specific impulse (Isp) of 1700 seconds, but the reaction temperature is too high for current engine materials. Diluting metallic hydrogen with liquid hydrogen can reduce the reaction temperature to levels compatible with current material limits and still provide an Isp greater than 900 s. Metallic hydrogen has not yet been produced on earth, but experimental techniques exist that may change this situation. This paper will provide a brief description of metallic hydrogen and the status of experiments that may soon produce detectable quantities of this material in the lab. Also provided are some characteristics for diluted metallic hydrogen engines and launch vehicles.

Simultaneous determination of iron, cadmium, zinc, copper, nickel, lead, and uranium in seawater by stable isotope dilution spark source mass spectrometry

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

Mykytiuk, A.P.; Russell, D.S.; Sturgeon, R.E.

Trace concentrations (ng/mL) of Fe, Cd, Zn, Cu, Ni, Pb, U, and Co have been determined in seawater by stable isotope dilution spark source mass spectrometry. The seawater samples were preconcentrated on the ion exchanger Chelex-100 and the concentrate was evaporated on a graphite or silver electrode. The results are compared with those obtained by graphite furnace atomic absorption spectrometry and inductively coupled plasma emission spectrometry. The technique avoids the use of calibration standards and is capable of producing results in cases where the analyte is only partially recovered. 2 tables.

The impact of sedimentary anisotropy on solute mixing in stacked scour-pool structures

NASA Astrophysics Data System (ADS)

Bennett, Jeremy P.; Haslauer, Claus P.; Cirpka, Olaf A.

2017-04-01

The spatial variability of hydraulic conductivity is known to have a strong impact on solute spreading and mixing. In most investigations, its local anisotropy has been neglected. Recent studies have shown that spatially varying orientation in sedimentary anisotropy can lead to twisting flow enhancing transverse mixing, but most of these studies used geologically implausible geometries. We use an object-based approach to generate stacked scour-pool structures with either isotropic or anisotropic filling which are typically reported in glacial outwash deposits. We analyze how spatially variable isotropic conductivity and variation of internal anisotropy in these features impacts transverse plume deformation and both longitudinal and transverse spreading and mixing. In five test cases, either the scalar values of conductivity or the spatial orientation of its anisotropy is varied between the scour-pool structures. Based on 100 random configurations, we compare the variability of velocity components, stretching and folding metrics, advective travel-time distributions, one and two-particle statistics in advective-dispersive transport, and the flux-related dilution indices for steady state advective-dispersive transport among the five test cases. Variation in the orientation of internal anisotropy causes strong variability in the lateral velocity components, which leads to deformation in transverse directions and enhances transverse mixing, whereas it hardly affects the variability of the longitudinal velocity component and thus longitudinal spreading and mixing. The latter is controlled by the spatial variability in the scalar values of hydraulic conductivity. Our results demonstrate that sedimentary anisotropy is important for transverse mixing, whereas it may be neglected when considering longitudinal spreading and mixing.

Soiled-bedding Sentinel Detection of Murine Norovirus 4

PubMed Central

Manuel, Christopher A; Hsu, Charlie C; Riley, Lela K; Livingston, Robert S

2008-01-01

According to serologic surveys, murine norovirus (MNV) is the most prevalent viral pathogen infecting mice used in biomedical research. However, the use of sentinel mice to detect MNV-infected mouse populations has not been evaluated thoroughly. To this end, an experimental method of soiled bedding transfer was created to mimic a quarterly sentinel monitoring program. Soiled bedding (15 or 30 cm3) from ICR mice experimentally infected with MNV4 was transferred weekly to cages of pair-housed 4-wk-old ICR mice. After 12 wk, both mice in 80% (4 of 5) of cages receiving either 15 or 30 cm3 of soiled bedding were seropositive for MNV and were shedding virus in feces. To evaluate the stability of MNV RNA in mouse feces, fecal pellets from MNV-infected sentinel mice were stored at room temperature for as long as 14 d. After storage, all fecal samples tested positive for MNV by RT-PCR. To determine whether fecal samples could be pooled for MNV detection, 1 MNV-positive fecal pellet was combined with either 9 or 19 MNV-negative fecal pellets. All pooled fecal samples were positive for MNV by RT-PCR at both dilutions. These data indicate that although MNV-infected mouse populations can be detected by exposing sentinel mice to MNV-contaminated bedding, detection failures can occur. In addition, there was high agreement in the MNV infection status of cohoused sentinel mice. These data also demonstrate that MNV is readily detectable in pooled fecal samples and in mouse feces stored at room temperature for 2 wk. PMID:18459710

[The human body burden of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls in residents' human breast milk from Beijing in 2007].

PubMed

Zhang, Lei; Liu, Yin-ping; Li, Jing-guang; Zhao, Yun-feng; Wu, Yong-ning

2013-06-01

To investigate contamination levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in human breast milk from Beijing residents, and evaluate the human body burden of PCDD/Fs and dl-PCBs of general population. A total of 110 human milk samples were collected from 11 regions in Beijing in 2007. After 11 pooled samples were made, concentrations of PCDD/Fs and dl-PCBs in breast milk pooled samples were measured by a high resolution gas chromatography - high resolution mass spectrometry (HRCG-HRMS) with isotope dilution. For congeners of PCDD/Fs and dl-PCBs in human breast milk from Beijing, the highest content of congeners was octachlorodibenzo-p-dioxin (OCDD), polychlorinated biphenyl (PCB)-118, and PCB-105 with the median of 20.6 pg/g fat, 4.07 ng/g fat and 1.63 ng/g fat, respectively. The concentration median of total dioxins in 11 pooled human milk samples from Beijing was 7.4 pg TEQ/g fat. The highest was 13.5 pg TEQ/g fat from Tongzhou, and the lowest was 4.3 pg TEQ/g fat from Pinggu. The contamination level of PCDD/Fs and dl-PCBs in human milk from Beijing is relatively low. However, with the rapid industrialization in China, the human body burden of PCDD/Fs and dl-PCBs will be likely to rise. Thus, further studies should be conducted to continuously monitor the trend of contamination level.

The EnVision++ system: a new immunohistochemical method for diagnostics and research. Critical comparison with the APAAP, ChemMate, CSA, LABC, and SABC techniques.

PubMed

Sabattini, E; Bisgaard, K; Ascani, S; Poggi, S; Piccioli, M; Ceccarelli, C; Pieri, F; Fraternali-Orcioni, G; Pileri, S A

1998-07-01

To assess a newly developed immunohistochemical detection system, the EnVision++. A large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision++ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate methods, when applied either manually or in a TechMate 500 immunostainer. With the vast majority of the antibodies, EnVision++ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMate techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision++ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard. The EnVision++ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload.

The EnVision++ system: a new immunohistochemical method for diagnostics and research. Critical comparison with the APAAP, ChemMate, CSA, LABC, and SABC techniques.

PubMed Central

Sabattini, E; Bisgaard, K; Ascani, S; Poggi, S; Piccioli, M; Ceccarelli, C; Pieri, F; Fraternali-Orcioni, G; Pileri, S A

1998-01-01

AIM: To assess a newly developed immunohistochemical detection system, the EnVision++. METHODS: A large series of differently processed normal and pathological samples and 53 relevant monoclonal antibodies were chosen. A chessboard titration assay was used to compare the results provided by the EnVision++ system with those of the APAAP, CSA, LSAB, SABC, and ChemMate methods, when applied either manually or in a TechMate 500 immunostainer. RESULTS: With the vast majority of the antibodies, EnVision++ allowed two- to fivefold higher dilutions than the APAAP, LSAB, SABC, and ChemMate techniques, the staining intensity and percentage of expected positive cells being the same. With some critical antibodies (such as the anti-CD5), it turned out to be superior in that it achieved consistently reproducible results with differently fixed or overfixed samples. Only the CSA method, which includes tyramide based enhancement, allowed the same dilutions as the EnVision++ system, and in one instance (with the anti-cyclin D1 antibody) represented the gold standard. CONCLUSIONS: The EnVision++ is an easy to use system, which avoids the possibility of disturbing endogenous biotin and lowers the cost per test by increasing the dilutions of the primary antibodies. Being a two step procedure, it reduces both the assay time and the workload. Images PMID:9797726

Spectrochemical determination of thorium in monazite by the powder-d.c. arc technique

USGS Publications Warehouse

Dutra, C.V.; Murata, K.J.

1954-01-01

Thorium in monazite is determined by a d.c. carbon-arc technique using zirconium as the internal standard. The analytical curve for Th II 2870.413 A??/Zr II 2844-579 A?? is established by means of synthetic standards containing graduated amounts of thoria and 0.500 per cent zirconia in pegmatite base (60 parts quartz, 40 parts microchne, and 1 part ferric oxide). Monazite samples are diluted 14-fold with pegmatite base that contains 0.538 per cent ZrO2, so that the zirconia content of the resulting mixture is also 0.500 per cent. In addition, both the standards and the diluted monazites are mixed with one-half their weight of powdered graphite. Approximately 25 mg of the prepared samples are arced to completion at 15.5 to 17.5 amperes. With the 14-fold dilution employed, the accurate range of the method is 3 to 20 per cent thoria in the original monazite. The coefficient of variation for a single determination is 4 per cent at the 7 per cent thoria level. Tests with synthetic unknowns and chemically analyzed monazites show a maximum error of ??10 per cent of the thoria content. If niobium is substituted for zirconium as the internal standard, there is a loss of precision. Platinum as the internal standard gives results of good precision but introduces a marked sensitivity to matrix effects. ?? 1954.

Seasonal and interannual dynamics of soil microbial biomass and available nitrogen in an alpine meadow in the eastern part of Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Xu, Bo; Wang, Jinniu; Wu, Ning; Wu, Yan; Shi, Fusun

2018-01-01

Soil microbial activity varies seasonally in frozen alpine soils during cold seasons and plays a crucial role in available N pool accumulation in soil. The intra- and interannual patterns of microbial and nutrient dynamics reflect the influences of changing weather factors, and thus provide important insights into the biogeochemical cycles and ecological functions of ecosystems. We documented the seasonal and interannual dynamics of soil microbial and available N in an alpine meadow in the eastern part of Qinghai-Tibet Plateau, China, between April 2011 and October 2013. Soil was collected in the middle of each month and analyzed for water content, microbial biomass C (MBC) and N (MBN), dissolved organic C and N, and inorganic N. Soil microbial community composition was measured by the dilution-plate method. Fungi and actinomycetes dominated the microbial community during the nongrowing seasons, and the proportion of bacteria increased considerably during the early growing seasons. Trends of consistently increasing MBC and available N pools were observed during the nongrowing seasons. MBC sharply declined during soil thaw and was accompanied by a peak in available N pool. Induced by changes in soil temperatures, significant shifts in the structures and functions of microbial communities were observed during the winter-spring transition and largely contributed to microbial reduction. The divergent seasonal dynamics of different N forms showed a complementary nutrient supply pattern during the growing season. Similarities between the interannual dynamics of microbial biomass and available N pools were observed, and soil temperature and water conditions were the primary environmental factors driving interannual fluctuations. Owing to the changes in climate, seasonal soil microbial activities and nutrient supply patterns are expected to change further, and these changes may have crucial implications for the productivity and biodiversity of alpine ecosystems.

40 CFR 1065.150 - Continuous sampling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Continuous sampling. 1065.150 Section... ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.150 Continuous sampling. You may use continuous sampling techniques for measurements that involve raw or dilute sampling. Make sure continuous sampling...

40 CFR 1065.150 - Continuous sampling.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Continuous sampling. 1065.150 Section... ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.150 Continuous sampling. You may use continuous sampling techniques for measurements that involve raw or dilute sampling. Make sure continuous sampling...

PARTICLE ASSOCIATION EFFECTS ON MICROBIAL INDICATOR CONCENTRATIONS FOR CSO DISINFECTION

EPA Science Inventory

The effect of blending on indicator microorganism concentrations in combined sewer overflow (CSO) was investigated due to concerns that standard techniques fail to measure particle-associated organisms found in sewage. It was shown that blending CSO samples diluted in a mixture ...

Attaining Low Temperatures

ERIC Educational Resources Information Center

Wheatley, John D.; Van Till, Howard J.

1970-01-01

Discusses the definition of temperature and the concept of order in non-mathematical terms. Describes the cooling techniques necessary in low temperature physics research, including magnetic cooling, the use of the Pomeranchuk Effect, and dilution refrigeration. Outlines the types of phenomena observed in matter within various temperature ranges…

Acid rain: Microphysical model

NASA Technical Reports Server (NTRS)

Dingle, A. N.

1980-01-01

A microphysical model was used to simulate the case of a ground cloud without dilution by entrainment and without precipitation. The numerical integration techniques of the model are presented. The droplet size spectra versus time and the droplet molalities for each value of time are discussed.

ASCANs Helms and Gregory swim in pool during Elgin AFB survival training

NASA Image and Video Library

1990-09-20

1990 Group 13 Astronaut Candidates (ASCANs) Susan J. Helms (foreground) and William G. Gregory, wearing helmets and flight suits, swim in pool at Elgin Air Force Base (AFB) in Pensacola, Florida, during water survival exercises. The training familiarized the candidates with survival techniques necessary in the event of a water landing. ASCANs participated in the exercises from 08-14-90 through 08-17-90.

Congener-specific determination of ultratrace levels of chlorinated and brominated polycyclic aromatic hydrocarbons in atmosphere and industrial stack gas by isotopic dilution gas chromatography/high resolution mass spectrometry method.

PubMed

Jin, Rong; Liu, Guorui; Zheng, Minghui; Fiedler, Heidelore; Jiang, Xiaoxu; Yang, Lili; Wu, Xiaolin; Xu, Yang

2017-08-04

Isotopic dilution gas chromatography combined with high resolution mass spectrometry (GC/HRMS) has overwhelming advantages with respect to the accuracy of congener-specific ultratrace analysis of complex persistent organic pollutants (POPs) in environmental matrices. However, an isotopic dilution GC/HRMS method for analysis of chlorinated and brominated polycyclic aromatic hydrocarbons (Cl-PAHs and Br-PAHs) using 13 C-labelled congeners as internal standards has not been established. In this study, a method for identification and quantification of 38 congeners of Cl-PAHs and Br-PAHs in atmosphere and stack gas samples from waste incinerators was developed using the isotopic dilution GC/HRMS technique. The instrumental detection limits of the GC/HRMS method ranged from 0.2pg to 1.8pg for Cl-PAH congeners, and 0.7pg to 2.7pg for Br-PAH congeners, which were about three orders of magnitude lower than those of the GC/quadrupole MS method. This new method developed was also the first to enable determination of Cl-PAH and Br-PAH homologs comprising congeners with the same molecular skeleton and chlorine or bromine substitution numbers. Among the detected congeners, seven Cl-PAH congeners and thirteen Br-PAH congeners that were abundant in the atmosphere and stack gases released from waste incinerators were firstly detected in real samples and reported using the established isotopic dilution GC/HRMS method. The developed isotopic dilution GC/HRMS is significant and needed for better studying the environmental behavior and health risk of Cl-PAHs and Br-PAHs. Copyright © 2017 Elsevier B.V. All rights reserved.

Numerical Modeling of Fluid Flow, Heat Transfer and Arc-Melt Interaction in Tungsten Inert Gas Welding

NASA Astrophysics Data System (ADS)

Li, Linmin; Li, Baokuan; Liu, Lichao; Motoyama, Yuichi

2017-04-01

The present work develops a multi-region dynamic coupling model for fluid flow, heat transfer and arc-melt interaction in tungsten inert gas (TIG) welding using the dynamic mesh technique. The arc-weld pool unified model is developed on basis of magnetohydrodynamic (MHD) equations and the interface is tracked using the dynamic mesh method. The numerical model for arc is firstly validated by comparing the calculated temperature profiles and essential results with the former experimental data. For weld pool convection solution, the drag, Marangoni, buoyancy and electromagnetic forces are separately validated, and then taken into account. Moreover, the model considering interface deformation is adopted in a stationary TIG welding process with SUS304 stainless steel and the effect of interface deformation is investigated. The depression of weld pool center and the lifting of pool periphery are both predicted. The results show that the weld pool shape calculated with considering the interface deformation is more accurate.

Nuclear pool of phosphatidylinositol 4 phosphate 5 kinase 1α is modified by polySUMO-2 during apoptosis

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

Chakrabarti, Rajarshi; Bhowmick, Debajit; Bhargava, Varsha

2013-09-20

Highlights: •Nuclear pool of PIP5K is SUMOylated. •Enhancement of SUMOylated nuclear PIP5K during apoptosis. •Nuclear PIP5K is modified by polySUMO-1 during apoptosis. •Nuclear PIP5K is modified by polySUMO-2 chain during apoptosis. -- Abstract: Phosphatidylinositol 4 phosphate 5 kinase 1α (PIP5K) is mainly localized in the cytosol and plasma membrane. Studies have also indicated its prominent association with nuclear speckles. The exact nature of this nuclear pool of PIP5K is not clear. Using biochemical and microscopic techniques, we have demonstrated that the nuclear pool of PIP5K is modified by SUMO-1 in HEK-293 cells stably expressing PIP5K. Moreover, this SUMOylated pool ofmore » PIP5K increased during apoptosis. PolySUMO-2 chain conjugated PIP5K was detected by pull-down experiment using affinity-tagged RNF4, a polySUMO-2 binding protein, during late apoptosis.« less

Constructed Pools-and-Riffles: Application and Assessment in Illinois.

NASA Astrophysics Data System (ADS)

Day, D. M.; Dodd, H. R.; Carney, D. A.; Holtrop, A. M.; Whiles, M. R.; White, B.; Roseboom, D.; Kinney, W.; Keefer, L. L.; Beardsley, J.

2005-05-01

The diversity of Illinois' streams provides a broad range of conditions, and thus a variety of restoration techniques may be required to adequately compensate for watershed alterations. Resource management agencies and research institutions in the state have collaborated on a variety of applied research initiatives to assess the efficacy of various stream protection and restoration techniques. Constructed pool-and-riffle structures have received significant attention because they tend to address watershed processes (i.e., channel evolution model) and may benefit biotic communities and processes along with physical habitat. Constructed pools-and-riffles have been applied primarily to address geomorphic instability, yet understanding biological responses can provide further rationale for their use and design specifications. In three stream systems around the state, fish were collected pre- and post- installation of structures, using primarily electrofishing techniques (e.g., electric seine & backpack). In general, within the first five years after installation, changes in fish communities have included a shift from high-abundance, small cyprinid-dominated assemblages to low-density Centrarchidae and Catostomidae assemblages. Changes in macro invertebrates at selected sites included increases in filter feeders and sensitive taxa such as the Ephemeroptera, Plecoptera, and Trichoptera (EPT). Ongoing assessments will be critical for understanding long-term influences on stream ecosystem structure and function.

Analysis of the linkage between rain and flood regime and its application to regional flood frequency estimation

NASA Astrophysics Data System (ADS)

Cunderlik, Juraj M.; Burn, Donald H.

2002-04-01

Improving techniques of flood frequency estimation at ungauged sites is one of the foremost goals of contemporary hydrology. River flood regime is a resultant reflection of a composite catchment hydrologic response to flood producing processes. In this sense the process of identifying homogeneous pooling groups can be plausibly based on catchment similarity in flood regime. Unfortunately the application of any pooling approach that is based on flood regime is restricted to gauged sites. Because flood regime can be markedly determined by rainfall regime, catchment similarity in rainfall regime can be an alternative option for identifying flood frequency pooling groups. An advantage of such a pooling approach is that rainfall data are usually spatially and temporary more abundant than flood data and the approach can also be applied at ungauged sites. Therefore in this study we have quantified the linkage between rainfall and flood regime and explored the appropriateness of substituting rainfall regime for flood regime in regional pooling schemes. Two different approaches to describing rainfall regime similarity using tools of directional statistics have been tested and used for evaluation of the potential of rainfall regime for identification of hydrologically homogeneous pooling groups. The outputs were compared to an existing pooling framework adopted in the Flood Estimation Handbook. The results demonstrate that regional pooling based on rainfall regime information leads to a high number of initially homogeneous groups and seems to be a sound pooling alternative for catchments with a close linkage between rain and flood regimes.

An investigation on characterizing dense coal-water slurry with ultrasound: theoretical and experimental method

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

Xue, M.H.; Su, M.X.; Dong, L.L.

2010-07-01

Particle size distribution and concentration in particulate two-phase flow are important parameters in a wide variety of industrial areas. For the purpose of online characterization in dense coal-water slurries, ultrasonic methods have many advantages such as avoiding dilution, the capability for being used in real time, and noninvasive testing, while light-based techniques are not capable of providing information because optical methods often require the slurry to be diluted. In this article, the modified Urick equation including temperature modification, which can be used to determine the concentration by means of the measurement of ultrasonic velocity in a coal-water slurry, is evaluatedmore » on the basis of theoretical analysis and experimental study. A combination of the coupled-phase model and the Bouguer-Lambert-Beer law is employed in this work, and the attenuation spectrum is measured within the frequency region from 3 to 12 MHz. Particle size distributions of the coal-water slurry at different volume fractions are obtained with the optimum regularization technique. Therefore, the ultrasonic technique presented in this work brings the possibility of using ultrasound for online measurements of dense slurries.« less

Recovery of 1,3-, 2,3-dichloropropenes, 1,2-dibromo-3-chloropropane, and o-, p-dichlorobenzenes from fatty and non-fat foodstuffs by liquid extraction technique.

PubMed

Daft, J L

1990-01-01

Food samples including fatty, non-fatty, grain-based, and nongrain-based types were fortified with the following five nematocides and fumigants: 1,3-dichloropropene, 2,3-dichloropropene, 1,2-dibromo-3-chloropropane, o-dichlorobenzene, and p-dichlorobenzene. Then, depending on sample consistency and type, the samples were diluted in, or extracted with organic solvent such as isooctane. A few of the high-fat extracts were passed through Florisil to remove excess fat or endogenous interferences. Analysis of the initial or cleaned up extracts was done by gas chromatography (GC) at 90 degrees C. The dichloropropenes were determined on 20% OV-101 columns with electron-capture and Hall electroconductivity detectors. The dichlorobenzenes and 1,2-dibromo-3-chloropropane, which elute beyond 30 min on the above columns, were determined on 5%-loaded columns using the same detectors. All five analytes were recovered from these techniques. Mean analyte recovery following a direct dilution or extraction was 83%, and following the Florisil cleanup step, was 52%. In 1986, a fumigant survey of about 200 foodstuffs by using this overall technique gave no findings of the five compounds studied here.

Use of blood-pool imaging in evaluation of diffuse activity patterns in technetium-99m pyrophosphate myocardial scintigraphy.

PubMed

Cowley, M J; Mantle, J A; Rogers, W J; Russell, R O; Rackley, C E; Logic, J R

1979-06-01

It has been suggested that diffuse Tc-99m pyrophosphate precordial activity may be due to persistent blood-pool activity in routine delayed views during myocardial imaging. To answer this question, we reviewed myocardial scintigrams recorded 60--90 min following the injection of 12--15 mCi of Tc-99m pyrophosphate for the presence of diffuse precordial activity, and compared these with early images of the blood pool in 265 patients. Diffuse activity in the delayed images was identified in 48 patients: in 20 with acute myocardial infarction and in 28 with no evidence of it. Comparison of these routine delayed images with early views of the blood pool revealed two types of patterns. In patients with acute infarction, 95% had delayed images that were distinguishable from blood pool either because the activity was smaller than the early blood pool, or by the presence of localized activity superimposed on diffuse activity identical to blood pool. In those without infarction, 93% had activity distribution in routine delayed views matching that in the early blood-pool images. The usefulness of the diffuse TcPPi precordial activity in myocardial infarction is improved when early blood-pool imaging is used to exclude persistence of blood-pool activity as its cause. Moreover, it does not require additional amounts of radioactivity nor complex computer processing, a feature that may be of value in the community hospital using the technique to "rule out" infarction 24--72 hr after onset of suggestive symptoms.

Empirical Validation of Pooled Whole Genome Population Re-Sequencing in Drosophila melanogaster

PubMed Central

Zhu, Yuan; Bergland, Alan O.; González, Josefa; Petrov, Dmitri A.

2012-01-01

The sequencing of pooled non-barcoded individuals is an inexpensive and efficient means of assessing genome-wide population allele frequencies, yet its accuracy has not been thoroughly tested. We assessed the accuracy of this approach on whole, complex eukaryotic genomes by resequencing pools of largely isogenic, individually sequenced Drosophila melanogaster strains. We called SNPs in the pooled data and estimated false positive and false negative rates using the SNPs called in individual strain as a reference. We also estimated allele frequency of the SNPs using “pooled” data and compared them with “true” frequencies taken from the estimates in the individual strains. We demonstrate that pooled sequencing provides a faithful estimate of population allele frequency with the error well approximated by binomial sampling, and is a reliable means of novel SNP discovery with low false positive rates. However, a sufficient number of strains should be used in the pooling because variation in the amount of DNA derived from individual strains is a substantial source of noise when the number of pooled strains is low. Our results and analysis confirm that pooled sequencing is a very powerful and cost-effective technique for assessing of patterns of sequence variation in populations on genome-wide scales, and is applicable to any dataset where sequencing individuals or individual cells is impossible, difficult, time consuming, or expensive. PMID:22848651

A web-oriented software for the optimization of pooled experiments in NGS for detection of rare mutations.

PubMed

Evangelista, Daniela; Zuccaro, Antonio; Lančinskas, Algirdas; Žilinskas, Julius; Guarracino, Mario R

2016-02-17

The cost per patient of next generation sequencing for detection of rare mutations may be significantly reduced using pooled experiments. Recently, some techniques have been proposed for the planning of pooled experiments and for the optimal allocation of patients into pools. However, the lack of a user friendly resource for planning the design of pooled experiments forces the scientists to do frequent, complex and long computations. OPENDoRM is a powerful collection of novel mathematical algorithms usable via an intuitive graphical user interface. It enables researchers to speed up the planning of their routine experiments, as well as, to support scientists without specific bioinformatics expertises. Users can automatically carry out analysis in terms of costs associated with the optimal allocation of patients in pools. They are also able to choose between three distinct pooling mathematical methods, each of which also suggests the optimal configuration for the submitted experiment. Importantly, in order to keep track of the performed experiments, users can save and export the results of their experiments in standard tabular and charts contents. OPENDoRM is a freely available web-oriented application for the planning of pooled NGS experiments, available at: http://www-labgtp.na.icar.cnr.it/OPENDoRM. Its easy and intuitive graphical user interface enables researchers to plan theirs experiments using novel algorithms, and to interactively visualize the results.

Microstructure characterization of a food-grade U-type microemulsion system by differential scanning calorimetry and electrical conductivity techniques.

PubMed

Zhang, Hui; Taxipalati, Maierhaba; Que, Fei; Feng, Fengqin

2013-12-01

The microstructure transitions of a food-grade U-type microemulsion system containing glycerol monolaurate and propionic acid at a 1:1 mass ratio as oil phase and Tween 80 as surfactant were investigated along a water dilution line at a ratio of 80:20 mass% surfactant/oil phase, based on a previously studied phase diagram. From the water thermal behaviours detected by differential scanning calorimetry, three structural regions are identified along the dilution line. In the first region, all water molecules are confined to the water core of the reverse micelles, leading to the formation of w/o microemulsion. As the water content increases, the water gains mobility, transforms into bicontinuous in the second region, and finally the microemulsion become o/w in the third region. The thermal transition points coincide with the structural phase transitions by electrical conductivity measurements, indicating that the structural transitions occur at 35 and 65 mass% of water along the dilution line. Copyright © 2013 Elsevier Ltd. All rights reserved.

Is the gas-particle partitioning in alpha-pinene secondary organic aerosol reversible?

NASA Astrophysics Data System (ADS)

Grieshop, Andrew P.; Donahue, Neil M.; Robinson, Allen L.

2007-07-01

This paper discusses the reversibility of gas-particle partitioning in secondary organic aerosol (SOA) formed from α-pinene ozonolysis in a smog chamber. Previously, phase partitioning has been studied quantitatively via SOA production experiments and qualitatively by perturbing temperature and observing particle evaporation. In this work, two methods were used to isothermally dilute the SOA: an external dilution sampler and an in-chamber technique. Dilution caused some evaporation of SOA, but repartitioning took place on a time scale of tens of minutes to hours-consistent with an uptake coefficient on the order of 0.001-0.01. However, given sufficient time, α-pinene SOA repartitions reversibly based on comparisons with data from conventional SOA yield experiments. Further, aerosol mass spectrometer (AMS) data indicate that the composition of SOA varies with partitioning. These results suggest that oligomerization observed in high-concentration laboratory experiments may be a reversible process and underscore the complexity of the kinetics of formation and evaporation of SOA.

Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability.

PubMed

Struzzi, Claudia; Scardamaglia, Mattia; Hemberg, Axel; Petaccia, Luca; Colomer, Jean-François; Snyders, Rony; Bittencourt, Carla

2015-01-01

Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.

Simultaneous regularization method for the determination of radius distributions from experimental multiangle correlation functions

NASA Astrophysics Data System (ADS)

Buttgereit, R.; Roths, T.; Honerkamp, J.; Aberle, L. B.

2001-10-01

Dynamic light scattering experiments have become a powerful tool in order to investigate the dynamical properties of complex fluids. In many applications in both soft matter research and industry so-called ``real world'' systems are subject of great interest. Here, the dilution of the investigated system often cannot be changed without getting measurement artifacts, so that one often has to deal with highly concentrated and turbid media. The investigation of such systems requires techniques that suppress the influence of multiple scattering, e.g., cross correlation techniques. However, measurements at turbid as well as highly diluted media lead to data with low signal-to-noise ratio, which complicates data analysis and leads to unreliable results. In this article a multiangle regularization method is discussed, which copes with the difficulties arising from such samples and enhances enormously the quality of the estimated solution. In order to demonstrate the efficiency of this multiangle regularization method we applied it to cross correlation functions measured at highly turbid samples.

Meta-Analytic Structural Equation Modeling (MASEM): Comparison of the Multivariate Methods

ERIC Educational Resources Information Center

Zhang, Ying

2011-01-01

Meta-analytic Structural Equation Modeling (MASEM) has drawn interest from many researchers recently. In doing MASEM, researchers usually first synthesize correlation matrices across studies using meta-analysis techniques and then analyze the pooled correlation matrix using structural equation modeling techniques. Several multivariate methods of…

Sericin supplementation improves semen freezability of buffalo bulls by minimizing oxidative stress during cryopreservation.

PubMed

Kumar, Pradeep; Kumar, Dharmendra; Sikka, P; Singh, P

2015-01-01

The variety of mammalian cells has been successfully cryopreserved by use of the silk protein sericin due to its strong free-radical-scavenging and potent antioxidant activity. The present study was conducted to examine the protective role of sericin on buffalo spermatozoa during cryopreservation. Semen of four breeding bulls was collected twice a week using artificial vagina technique. The ejaculates of four bulls were pooled, divided into five equal fractions, diluted with the extender supplemented with different concentrations of sericin (0, 0.25, 0.5, 1.5 and 2%) and then cryopreserved. Post-thawed motility was objectively assessed by computer assisted sperm analyzer. Sperm plasma membrane integrity was assessed by hypo-osmotic swelling test (HOST). Malondialdehyde (MDA) concentration, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were determined in frozen-thawed extended seminal plasma by spectrophotometry. The extender supplemented with 0.25, 0.5 and 1% sericin resulted in the higher sperm motility and GPx acivity. Furthermore, plasma membrane integrity and SOD activity were found to be higher (P<0.05) in group supplemented with 0.25 and 0.5% sericin (P<0.05). The MDA concentration was found to be significantly lower (P<0.05) in 0.25 and 0.5% sericin treated groups than control and other treated groups. In conclusion, the supplementation of 0.25-0.5% sericin in semen extender improves frozen-thawed semen quality through protecting sperm from oxidative stress. Copyright © 2014 Elsevier B.V. All rights reserved.

Welding Residual Stress Analysis and Fatigue Strength Assessment at Elevated Temperature for Multi-pass Dissimilar Material Weld Between Alloy 617 and P92 Steel

NASA Astrophysics Data System (ADS)

Lee, Juhwa; Hwang, Jeongho; Bae, Dongho

2018-03-01

In this paper, welding residual stress analysis and fatigue strength assessment were performed at elevated temperature for multi-pass dissimilar material weld between Alloy 617 and P92 steel, which are used in thermal power plant. Multi-pass welding between Alloy 617 and P92 steel was performed under optimized welding condition determined from repeated pre-test welding. In particular, for improving dissimilar material weld-ability, the buttering welding technique was applied on the P92 steel side before multi-pass welding. Welding residual stress distribution at the dissimilar material weld joint was numerically analyzed by using the finite element method, and compared with experimental results which were obtained by the hole-drilling method. Additionally, fatigue strength of dissimilar material weld joint was assessed at the room temperature (R.T), 300, 500, and 700 °C. In finite element analysis results, numerical peak values; longitudinal (410 MPa), transverse (345 MPa) were higher than those of experiments; longitudinal (298 MPa), transverse (245 MPa). There are quantitatively big differences between numerical and experimental results, due to some assumption about the thermal conductivity, specific heat, effects of enforced convection of the molten pool, dilution, and volume change during phase transformation caused by actual shield gas. The low fatigue limit at R.T, 300 °C, 500 °C and 700 °C was assessed to be 368, 276, 173 and 137 MPa respectively.

Welding Residual Stress Analysis and Fatigue Strength Assessment at Elevated Temperature for Multi-pass Dissimilar Material Weld Between Alloy 617 and P92 Steel

NASA Astrophysics Data System (ADS)

Lee, Juhwa; Hwang, Jeongho; Bae, Dongho

2018-07-01

In this paper, welding residual stress analysis and fatigue strength assessment were performed at elevated temperature for multi-pass dissimilar material weld between Alloy 617 and P92 steel, which are used in thermal power plant. Multi-pass welding between Alloy 617 and P92 steel was performed under optimized welding condition determined from repeated pre-test welding. In particular, for improving dissimilar material weld-ability, the buttering welding technique was applied on the P92 steel side before multi-pass welding. Welding residual stress distribution at the dissimilar material weld joint was numerically analyzed by using the finite element method, and compared with experimental results which were obtained by the hole-drilling method. Additionally, fatigue strength of dissimilar material weld joint was assessed at the room temperature (R.T), 300, 500, and 700 °C. In finite element analysis results, numerical peak values; longitudinal (410 MPa), transverse (345 MPa) were higher than those of experiments; longitudinal (298 MPa), transverse (245 MPa). There are quantitatively big differences between numerical and experimental results, due to some assumption about the thermal conductivity, specific heat, effects of enforced convection of the molten pool, dilution, and volume change during phase transformation caused by actual shield gas. The low fatigue limit at R.T, 300 °C, 500 °C and 700 °C was assessed to be 368, 276, 173 and 137 MPa respectively.

Charge Generation and Recombination in Organic Materials for Photovoltaics

NASA Astrophysics Data System (ADS)

Ramirez, Jessica Jacklyn

Understanding the nature of molecular exciton states is critical for the design of organic photovoltaic materials that push current device efficiencies into the next realm. This thesis describes several research projects that have sought to further our understanding of the generation and recombination of charge carriers, facilitated by such excitonic states, in organic systems. We begin with fundamental studies on the excited-state dynamics of several fullerene derivatives. We also venture away from the traditional fullerene-based electron acceptors and consider several derivatized perylene diimides as alternate electron acceptors. We then report on the observation of a broad, structureless, emission emanating from charge-generating films comprised of perfluoroalkyl fullerene derivatives dilutely dispersed in polyfluorene hosts. We have determined that this red-shifted PL signature is the result of radiative recombination from a charge-transfer state that is populated initially as a precursor to charge generation, and may be repopulated upon charge recombination. Our data offers an observable link between charge-generation and charge-transfer emission that is kinetically associated with carrier recombination, and we utilize this link to probe the influence of driving force and polymer microstructure in the fundamental processes of charge generation and decay in small molecule/polymer heterojunctions. Thereafter, we sought to develop our understanding of a novel photophysical mechanism (known as energy pooling) which would allow for the energy of multiple excitons to be 'pooled' towards a central molecular moiety, where the individual exciton energies may add together to create a single highly excited excitonic state. This upconversion-like process would facilitate more efficient photocurrent generation in devices utilizing this mode of charge separation. The primary modes of inquiry utilized in this work come from the spectroscopic techniques of absorbance, steady-state and time-resolved photoluminescence, transient absorption and time-resolved microwave conductivity. Some secondary methods employed include cyclic voltammetry, X-ray diffraction and computational tools from density functional theory. This utilization of both experimental and theoretical methodologies provides a powerful approach to furthering our understanding of both the fundamental photophysics of the systems studied, as well as the charge generation and recombination pathways occurring at organic donor-acceptor interfaces, helping to guide the design of more efficient organic photovoltaics.

Metabolic pathways promoting intrahepatic fatty acid accumulation in methionine and choline deficiency: implications for the pathogenesis of steatohepatitis.

PubMed

Macfarlane, David P; Zou, Xiantong; Andrew, Ruth; Morton, Nicholas M; Livingstone, Dawn E W; Aucott, Rebecca L; Nyirenda, Moffat J; Iredale, John P; Walker, Brian R

2011-02-01

The pathological mechanisms that distinguish simple steatosis from steatohepatitis (or NASH, with consequent risk of cirrhosis and hepatocellular cancer) remain incompletely defined. Whereas both a methionine- and choline-deficient diet (MCDD) and a choline-deficient diet (CDD) lead to hepatic triglyceride accumulation, MCDD alone is associated with hepatic insulin resistance and inflammation (steatohepatitis). We used metabolic tracer techniques, including stable isotope ([¹³C₄]palmitate) dilution and mass isotopomer distribution analysis (MIDA) of [¹³C₂]acetate, to define differences in intrahepatic fatty acid metabolism that could explain the contrasting effect of MCDD and CDD on NASH in C57Bl6 mice. Compared with control-supplemented (CS) diet, liver triglyceride pool sizes were similarly elevated in CDD and MCDD groups (24.37 ± 2.4, 45.94 ± 3.9, and 43.30 ± 3.5 μmol/liver for CS, CDD, and MCDD, respectively), but intrahepatic neutrophil infiltration and plasma alanine aminotransferase (31 ± 3, 48 ± 4, 231 ± 79 U/l, P < 0.05) were elevated only in MCDD mice. However, despite loss of peripheral fat in MCDD mice, neither the rate of appearance of palmitate (27.2 ± 3.5, 26.3 ± 2.3, and 28.3 ± 3.5 μmol·kg⁻¹·min⁻¹) nor the contribution of circulating fatty acids to the liver triglyceride pool differed between groups. Unlike CDD, MCDD had a defect in hepatic triglyceride export that was confirmed using intravenous tyloxapol (142 ± 21, 122 ± 15, and 80 ± 7 mg·kg⁻¹·h⁻¹, P < 0.05). Moreover, hepatic de novo lipogenesis was significantly elevated in the MCDD group only (1.4 ± 0.3, 2.3 ± 0.4, and 3.4 ± 0.4 μmol/day, P < 0.01). These findings suggest that important alterations in hepatic fatty acid metabolism may promote the development of steatohepatitis. Similar mechanisms may predispose to hepatocyte damage in human NASH.

Mapping Neglected Swimming Pools from Satellite Data for Urban Vector Control

NASA Astrophysics Data System (ADS)

Barker, C. M.; Melton, F. S.; Reisen, W. K.

2010-12-01

Neglected swimming pools provide suitable breeding habit for mosquitoes, can contain thousands of mosquito larvae, and present both a significant nuisance and public health risk due to their inherent proximity to urban and suburban populations. The rapid increase and sustained rate of foreclosures in California associated with the recent recession presents a challenge for vector control districts seeking to identify, treat, and monitor neglected pools. Commercial high resolution satellite imagery offers some promise for mapping potential neglected pools, and for mapping pools for which routine maintenance has been reestablished. We present progress on unsupervised classification techniques for mapping both neglected pools and clean pools using high resolution commercial satellite data and discuss the potential uses and limitations of this data source in support of vector control efforts. An unsupervised classification scheme that utilizes image segmentation, band thresholds, and a change detection approach was implemented for sample regions in Coachella Valley, CA and the greater Los Angeles area. Comparison with field data collected by vector control personal was used to assess the accuracy of the estimates. The results suggest that the current system may provide some utility for early detection, or cost effective and time efficient annual monitoring, but additional work is required to address spectral and spatial limitations of current commercial satellite sensors for this purpose.

Dark-Blood Delayed Enhancement Cardiac Magnetic Resonance of Myocardial Infarction.

PubMed

Kim, Han W; Rehwald, Wolfgang G; Jenista, Elizabeth R; Wendell, David C; Filev, Peter; van Assche, Lowie; Jensen, Christoph J; Parker, Michele A; Chen, Enn-Ling; Crowley, Anna Lisa C; Klem, Igor; Judd, Robert M; Kim, Raymond J

2017-12-08

This study introduced and validated a novel flow-independent delayed enhancement technique that shows hyperenhanced myocardium while simultaneously suppressing blood-pool signal. The diagnosis and assessment of myocardial infarction (MI) is crucial in determining clinical management and prognosis. Although delayed enhancement cardiac magnetic resonance (DE-CMR) is an in vivo reference standard for imaging MI, an important limitation is poor delineation between hyperenhanced myocardium and bright LV cavity blood-pool, which may cause many infarcts to become invisible. A canine model with pathology as the reference standard was used for validation (n = 22). Patients with MI and normal controls were studied to ascertain clinical performance (n = 31). In canines, the flow-independent dark-blood delayed enhancement (FIDDLE) technique was superior to conventional DE-CMR for the detection of MI, with higher sensitivity (96% vs. 85%, respectively; p = 0.002) and accuracy (95% vs. 87%, respectively; p = 0.01) and with similar specificity (92% vs, 92%, respectively; p = 1.0). In infarcts that were identified by both techniques, the entire length of the endocardial border between infarcted myocardium and adjacent blood-pool was visualized in 33% for DE-CMR compared with 100% for FIDDLE. There was better agreement for FIDDLE-measured infarct size than for DE-CMR infarct size (95% limits-of-agreement, 2.1% vs. 5.5%, respectively; p < 0.0001). In patients, findings were similar. FIDDLE demonstrated higher accuracy for diagnosis of MI than DE-CMR (100% [95% confidence interval [CI]: 89% to 100%] vs. 84% [95% CI: 66% to 95%], respectively; p = 0.03). The study introduced and validated a novel CMR technique that improves the discrimination of the border between infarcted myocardium and adjacent blood-pool. This dark-blood technique provides diagnostic performance that is superior to that of the current in vivo reference standard for the imaging diagnosis of MI. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Boiling heat transfer to LN2 and LH2 - Influence of surface orientation and reduced body forces

NASA Technical Reports Server (NTRS)

Merte, H., Jr.; Oker, E.; Littles, J. W.

1973-01-01

The quantitative determination of the influence of heater surface orientation and gravity on nucleate pool boiling of liquid nitrogen and liquid hydrogen is described. A transient calorimeter technique, well suited for obtaining pool boiling data under reduced gravity and used earlier by Clark and Merte (1963), was employed after being adapted to flat a surface whose orientation could be varied. The obtained determination results are reviewed.

Price of Fairness in Kidney Exchange

DTIC Science & Technology

2014-05-01

solver uses branch-and-price, a technique that proves optimality by in- crementally generating only a small part of the model during tree search [8...factors like fail- ure probability and chain position, as in the probabilistic model ). We will use this multiplicative re-weighting in our experiments in...Table 2 gives the average loss in efficiency for each of these models over multiple generated pool sizes, with 40 runs per pool size per model , under

Biogeochemical implications of labile phosphorus in forest soils determined by the Hedley fractionation procedure.

PubMed

Johnson, Arthur H; Frizano, Jaqueline; Vann, David R

2003-05-01

Forest ecologists and biogeochemists have used a variety of extraction techniques to assess labile vs. non-labile soil P pools in chronosequences, the balance between biological vs. geochemical control of P transformations across a wide range of soil orders, the role of plants with either N-fixing or mycorrhizal symbionts in controlling soil P fractions, and to make inferences about plant-available P. Currently, variants of the sequential extraction procedure developed by M. J. Hedley and co-workers afford the greatest discrimination among labile and non-labile organic and inorganic P pools. Results of recent studies that used this technique to evaluate P fractions in forest soils indicate the following: (1) in intact, highly weathered forest soils of the humid tropics, Hedley-labile P values are several times larger than extractable P values resulting from mildly acidic extracting solutions which were commonly used in the past 2 decades; (2) pools of Hedley-labile P are several times larger than the annual forest P requirement and P required from the soil annually in both temperate and tropical forests; (3) long-term trends in non-labile P pools during pedogenesis are adequately represented by the Walker and Syers' model of changes in P fractionation during soil development. However, to better represent trends in pools that can supply plant-available P across forest soils of different age and weathering status, the paradigm should be modified; and (4) across a wide range of tropical and temperate forest soils, organic matter content is an important determinant of Hedley-labile P.

TDS exposure project: relevance of the total diet study approach for different groups of substances.

PubMed

Vin, Karine; Papadopoulos, Alexandra; Cubadda, Francesco; Aureli, Federica; Oktay Basegmez, Hatice Imge; D'Amato, Marilena; De Coster, Sam; D'Evoli, Laura; López Esteban, María Teresa; Jurkovic, Martina; Lucarini, Massimo; Ozer, Hayrettin; Fernández San Juan, Pedro Mario; Sioen, Isabelle; Sokolic, Darja; Turrini, Aida; Sirot, Véronique

2014-11-01

A method to validate the relevance of the Total Diet Study (TDS) approach for different types of substances is described. As a first step, a list of >2800 chemicals classified into eight main groups of relevance for food safety (natural components, environmental contaminants, substances intentionally added to foods, residues, naturally occurring contaminants, process contaminants, contaminants from packaging and food contact materials, other substances) has been established. The appropriateness of the TDS approach for the different substance groups has then been considered with regard to the three essential principles of a TDS: representativeness of the whole diet, pooling of foods and food analyzed as consumed. Four criteria were considered for that purpose (i) the substance has to be present in a significant part of the diet or predominantly present in specific food groups, (ii) a robust analytical method has to be available to determine it in potential contributors to the dietary exposure of the population, and (iii) the dilution impact of pooling and (iv) the impact of everyday food preparation methods on the concentration of the substance are assessed. For most of the substances the TDS approach appeared to be relevant and any precautions to be taken are outlined. Copyright © 2014 Elsevier Ltd. All rights reserved.

Online Measurement of Exhaled NO Concentration and Its Production Sites by Fast Non-equilibrium Dilution Ion Mobility Spectrometry

NASA Astrophysics Data System (ADS)

Peng, Liying; Jiang, Dandan; Wang, Zhenxin; Liu, Jiwei; Li, Haiyang

2016-03-01

Exhaled nitric oxide (NO) is one of the most promising breath markers for respiratory diseases. Its profile for exhalation and the respiratory NO production sites can provide useful information for medical disease diagnosis and therapeutic procedures. However, the high-level moisture in exhaled gas always leads to the poor selectivity and sensitivity for ion spectrometric techniques. Herein, a method based on fast non-equilibrium dilution ion mobility spectrometry (NED-IMS) was firstly proposed to directly monitor the exhaled NO profile on line. The moisture interference was eliminated by turbulently diluting the original moisture to 21% of the original with the drift gas and dilution gas. Weak enhancement was observed for humid NO response and its limit of detection at 100% relative humidity was down to 0.58 ppb. The NO concentrations at multiple exhalation flow rates were measured, while its respiratory production sites were determined by using two-compartment model (2CM) and Högman and Meriläinen algorithm (HMA). Last but not the least, the NO production sites were analyzed hourly to tentatively investigate the daily physiological process of NO. The results demonstrated the capacity of NED-IMS in the real-time analysis of exhaled NO and its production sites for clinical diagnosis and assessment.

Automated agar plate streaker: a linear plater on Society for Biomolecular Sciences standard plates.

PubMed

King, Gregory W; Kath, Gary S; Siciliano, Sal; Simpson, Neal; Masurekar, Prakash; Sigmund, Jan; Polishook, Jon; Skwish, Stephen; Bills, Gerald; Genilloud, Olga; Peláez, Fernando; Martín, Jesus; Dufresne, Claude

2006-09-01

Several protocols for bacterial isolation and techniques for aerobic plate counting rely on the use of a spiral plater to deposit concentration gradients of microbial suspensions onto a circular agar plate to isolate colony growth. The advantage of applying a gradient of concentrations across the agar surface is that the original microbiological sample can be applied at a single concentration rather than as multiple serial dilutions. The spiral plater gradually dilutes the sample across a compact area and therefore saves time preparing dilutions and multiple agar plates. Commercial spiral platers are not automated and require manual sample loading. Dispensing of the sample volume and rate of gradients are often very limited in range. Furthermore, the spiral sample application cannot be used with rectangular microplates. Another limitation of commercial spiral platers is that they are useful only for dilute, filtered suspensions and cannot plate suspensions of coarse organic particles therefore precluding the use of many kinds of microorganism-containing substrata. An automated agar plate spreader capable of processing 99 rectangular microplates in unattended mode is described. This novel instrument is capable of dispensing discrete volumes of sample in a linear pattern. It can be programmed to dispense a sample suspense at a uniform application rate or across a decreasing concentration gradient.

THE PREPARATION AND PROPERTIES OF HIGHLY PURIFIED ASCORBIC ACID OXIDASE

PubMed Central

Powers, Wendell H.; Lewis, Stanley; Dawson, Charles R.

1944-01-01

1. A method is described for the preparation of a highly purified ascorbic acid oxidase containing 0.24 per cent copper. 2. Using comparable activity measurements, this oxidase is about one and a half times as active on a dry weight basis as the hitherto most highly purified preparation described by Lovett-Janison and Nelson. The latter contained 0.15 per cent copper. 3. The oxidase activity is proportional to the copper content and the proportionality factor is the same as that reported by Lovett-Janison and Nelson. 4. When dialyzed free of salt, the blue concentrated oxidase solutions precipitate a dark green-blue protein which carries the activity. This may be prevented by keeping the concentrated solutions about 0.1 M in Na2HPO4. 5. When highly diluted for activity measurements the oxidase rapidly loses activity (irreversibly) previous to the measurement, unless the dilution is made with a dilute inert protein (gelatin) solution. Therefore activity values obtained using such gelatin-stabilized dilute solutions of the oxidase run considerably higher than values obtained by the Lovett-Janison and Nelson technique. 6. The effect of pH and substrate concentration on the activity of the purified oxidase in the presence and absence of inert protein was studied. PMID:19873382

Relationship-Centered Counseling: The Integrative Interaction of Relationship and Technique.

ERIC Educational Resources Information Center

Kelly, Eugene W., Jr.

Efforts toward integration and eclecticism in counseling and psychotherapy reflect continuing interest in systematically blending theoretical commonalties and eclectically using a variety of techniques across different schools of therapy in the hope of achieving a constituent working model that pools the strengths of different theories and…

Radiochemical separation of gallium by amalgam exchange

USGS Publications Warehouse

Ruch, R.R.

1969-01-01

An amalgam-exchange separation of radioactive gallium from a number of interfering radioisotopes has been developed. A dilute (ca. 0.3%) gallium amalgam is agitated with a slightly acidic solution of 72Ga3+ containing concentrations of sodium thiocyanate and either perchlorate or chloride. The amalgam is then removed and the radioactive gallium stripped by agitation with dilute nitric acid. The combined exchange yield of the perchlorate-thiocyanate system is 90??4% and that of the chloride-thiocyanate system is 75??4%. Decontamination yields of most of the 11 interfering isotopes studied were less than 0.02%. The technique is applicable for use with activation analysis for the determination of trace amounts of gallium. ?? 1969.

Determination of uranium and thorium in materials associated with real time electronic solar neutrino detectors

NASA Astrophysics Data System (ADS)

Fassett, J. D.; Kelly, W. R.

1992-07-01

The application of isotope dilution thermal ionization mass spectrometry to the determination of both uranium and thorium in four different target materials used or proposed for electronic neutrino detectors is described. Isotope dilution analysis is done using highly enriched 233U and 230Th separated isotopes. Sensitivity of the technique is such that sub-picogram amounts of material are readily measured. The overall limit to measurement is caused by contamination of these elements during the measurement process. Uranium is more easily measured than thorium because both the instrumental sensitivity is higher and contamination is better controlled. The materials analyzed were light and heavy water, pseudocumene, and mineral oil.

Comparison of Some Secondary Body Composition Algorithms

ERIC Educational Resources Information Center

Sutton, Robert A.; Miller, Carolyn

2006-01-01

Body composition measurements vary greatly in degree of measurement difficulty and accuracy. Hydrostatic weighing, chemical dilution or their equivalents were the accepted "gold" standards for assessing fat mass. Dual Energy X-ray Absorptiometry (DEXA) is fast replacing these techniques as the preferred standard. However, these direct measurement…

Classification and outcomes of extended arch repair for acute Type A aortic dissection: a systematic review and meta-analysis.

PubMed

Smith, Holly N; Boodhwani, Munir; Ouzounian, Maral; Saczkowski, Richard; Gregory, Alexander J; Herget, Eric J; Appoo, Jehangir J

2017-03-01

Distal extent of repair in patients undergoing surgery for acute Type A aortic dissection (ATAAD) is controversial. Emerging hybrid techniques involving open and endovascular surgery have been reported in small numbers by select individual centres. A systematic review and meta-analysis was performed to investigate the outcomes following extended arch repair for ATAAD. A classification system is proposed of the different techniques to facilitate discussion and further investigation. Using Ovid MEDLINE, 38 studies were identified reporting outcomes for 2140 patients. Studies were categorized into four groups on the basis of extent of surgical aortic resection and the method of descending thoracic aortic stent graft deployment; during circulatory arrest (frozen stented elephant trunk) or with normothermic perfusion and use of fluoroscopy (warm stent graft): (I) surgical total arch replacement, (II) total arch and frozen stented elephant trunk, (III) hemiarch and frozen stented elephant trunk and (IV) total arch and warm stent graft. Perioperative event rates were obtained for each of the four groups and the entire cohort using pooled summary estimates. Linearized rates of late mortality and reoperation were calculated. Overall pooled hospital mortality for extended arch techniques was 8.6% (95% CI 7.2-10.0). Pooled data categorized by surgical technique resulted in hospital mortality of 11.9% for total arch, 8.6% total arch and frozen stented elephant trunk, 6.3% hemiarch and frozen stented elephant trunk and 5.5% total arch and 'warm stent graft'. Overall incidence of stroke for the entire cohort was 5.7% (95% CI 3.6-8.2). Rate of spinal cord ischaemia was 2.0% (95% CI 1.2-3.0). Pooled linearized rate of late mortality was 1.66%/pt-yr (95% CI 1.34-2.07) with linearized rate of re-operation of 1.62%/pt-yr (95% CI 1.24-2.05). Perioperative results of extended arch procedures are encouraging. Further follow-up is required to see if long-term complications are reduced with these emerging techniques. The proposed classification system will facilitate future comparison of short- and long-term results of different techniques of extended arch repair for ATAAD. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Detection of Mycobacterium avium subspecies paratuberculosis in tie-stall dairy herds using a standardized environmental sampling technique and targeted pooled samples.

PubMed

Arango-Sabogal, Juan C; Côté, Geneviève; Paré, Julie; Labrecque, Olivia; Roy, Jean-Philippe; Buczinski, Sébastien; Doré, Elizabeth; Fairbrother, Julie H; Bissonnette, Nathalie; Wellemans, Vincent; Fecteau, Gilles

2016-07-01

Mycobacterium avium ssp. paratuberculosis (MAP) is the etiologic agent of Johne's disease, a chronic contagious enteritis of ruminants that causes major economic losses. Several studies, most involving large free-stall herds, have found environmental sampling to be a suitable method for detecting MAP-infected herds. In eastern Canada, where small tie-stall herds are predominant, certain conditions and management practices may influence the survival and transmission of MAP and recovery (isolation). Our objective was to estimate the performance of a standardized environmental and targeted pooled sampling technique for the detection of MAP-infected tie-stall dairy herds. Twenty-four farms (19 MAP-infected and 5 non-infected) were enrolled, but only 20 were visited twice in the same year, to collect 7 environmental samples and 2 pooled samples (sick cows and cows with poor body condition). Concurrent individual sampling of all adult cows in the herds was also carried out. Isolation of MAP was achieved using the MGIT Para TB culture media and the BACTEC 960 detection system. Overall, MAP was isolated in 7% of the environmental cultures. The sensitivity of the environmental culture was 44% [95% confidence interval (CI): 20% to 70%] when combining results from 2 different herd visits and 32% (95% CI: 13% to 57%) when results from only 1 random herd visit were used. The best sampling strategy was to combine samples from the manure pit, gutter, sick cows, and cows with poor body condition. The standardized environmental sampling technique and the targeted pooled samples presented in this study is an alternative sampling strategy to costly individual cultures for detecting MAP-infected tie-stall dairies. Repeated samplings may improve the detection of MAP-infected herds.

Physical and chemical differences between natural and artificial pools in blanket peatlands

NASA Astrophysics Data System (ADS)

Turner, Ed; Baird, Andy; Billett, Mike; Chapman, Pippa; Dinsmore, Kerry; Holden, Joseph

2014-05-01

Natural pools are common features of many northern peatlands. Numerous artificial pools are being created behind dams installed during drain-blocking, a common peatland restoration technique, significantly increasing the area of open water. Natural pools are known to be major sources of GHGs (e.g. Hamilton et al. 1994), but the reasons they are such 'hotspots' is poorly understood. We hypothesize that pools act as 'biochemical reactors' of particulate and dissolved organic carbon (POC and DOC) transported from surrounding peat that is processed into a range of products including CH4 and CO2. Therefore, understanding the processes operating in both natural and artificial pool systems is fundamental to elucidating this hypothesis. Water levels and temperature have been continuously monitored at six natural and six artificial pools within the 'Flow Country' blanket peatland in northern Scotland since May 2013. Bi-weekly sampling of waters from pools, peat matrix through-flow (via piezometers) and surface flow has been conducted for analysis of DOC, POC, DIC, CH4diss and CO2diss, together with GHG flux measurements from pool surfaces and adjacent peat. We show that, to date, pool water levels rapidly respond to rainfall, although artificial pools appear to respond with greater magnitude. For example, over the course of same rainfall event (20-23 June 2013), natural and artificial pool levels increased between 5.3 and 9.8 cm, and 12.5 and 22.6 cm respectively. Temperature measured at c. 5 cm from the base of each pool shows distinct diurnal fluctuations, which are of greater magnitude in all but one of the natural pools compared to the artificial pools: over the same period (20-23 July 2013), the maximum diurnal variation at the artificial pool site was 5.1 °C compared to 9.2 °C within the natural pools. Vegetation cover is generally higher in artificial pools and may have a moderating effect on variations in pool temperature. Results of pool-water DOC analysis from regular sampling at the study site and a wider regional survey indicate DOC concentrations are consistently higher in artificial pools. The implications of these preliminary results in relation to the carbon cycle and GHGs of blanket peatlands are briefly discussed. Hamilton, J. D., Kelly, C. A., Rudd, J. W. M., Hesslein, R. H. and Roulet, N. T. (1994) Flux to the atmosphere of CH4 and CO2 from wetland ponds on the Hudson Bay lowlands (HBLs). Journal of Geophysical Research 99, 1495-1510.

River flow and ammonium discharge determine spring phytoplankton blooms in an urbanized estuary

NASA Astrophysics Data System (ADS)

Dugdale, Richard; Wilkerson, Frances; Parker, Alexander E.; Marchi, Al; Taberski, Karen

2012-12-01

Nutrient loadings to urbanized estuaries have increased over the past decades in response to population growth and upgrading to secondary sewage treatment. Evidence from the San Francisco Estuary (SFE) indicates that increased ammonium (NH4) loads have resulted in reduced primary production, a counter-intuitive finding; the NH4 paradox. Phytoplankton uptake of nitrate (NO3), the largest pool of dissolved inorganic nitrogen, is necessary for blooms to occur in SFE. The relatively small pool of ambient NH4, by itself insufficient to support a bloom, prevents access to NO3 and bloom development. This has contributed to the current rarity of spring phytoplankton blooms in the northern SFE (Suisun Bay), in spite of high inorganic nutrient concentrations, improved water transparency and seasonally low biomass of bivalve grazers. The lack of blooms has likely contributed to deleterious bottom-up impacts on estuarine fish. This bloom suppression may also occur in other estuaries that receive large amounts of anthropogenic NH4. In 2010 two rare diatom blooms were observed in spring in Suisun Bay (followed by increased abundances of copepods and pelagic fish), and like the prior bloom observed in 2000, chlorophyll accumulated after NH4 concentrations were decreased. In 2010, low NH4 concentrations were apparently due to a combination of reduced NH4 discharge from a wastewater treatment plant and increased river flow. To understand the interactions of river flow, NH4 discharge and bloom initiation, a conceptual model was constructed with three criteria; 1) NH4 loading must not exceed the capacity of the phytoplankton to assimilate the inflow of NH4, 2) the NH4 concentration must be ≤4 μmol L-1 to enable phytoplankton NO3 uptake, 3) the dilution rate of phytoplankton biomass set by river flow must not exceed the phytoplankton growth rate to avoid "washout". These criteria were determined for Suisun Bay; with sufficient irradiance and present day discharge of 15 tons NH4-N d-1at the upstream wastewater treatment plant (WTP). The loading criterion requires phytoplankton NH4 uptake to exceed 1.58 mmol m-2 d-1; the concentration criterion requires river flow >800 m3 s-1 at the WTP for sufficient NH4 dilution and the washout criterion requires river flow at Suisun Bay <1100 m3 s-1. The model and criteria are used to suggest how a reduction in anthropogenic NH4, either by reduced discharge or increased dilution (river flow), could be used as a management tool to restore pre-existing productivity in the SFE and similarly impacted estuaries.

The superiority of indium ratio over blood pool subtraction in analysis of indium-111 platelet deposition on thoraco-abdominal prosthetic grafts

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

Ripley, S.; Wakefield, T.; Spaulding, S.

1985-05-01

In this investigation platelet deposition in polytetrafluroethylene (PTFE) thoracoabdominal grafts (TAC's) was evaluated using two different semi-quantitative techniques. Ten PTFE TAG's 6 mm in diameter and 30 cm in length were inserted into 10 mongrel dogs. One, 4 and 6 weeks after graft implantation the animals were injected with autologous In-111 platelets labelled by a modified Thakur technique. Platelet imaging in grafts was performed 48 hrs after injection. Blood pool was determined by Tc99m labelled RBC's (in vivo/in vitro technique). Semi-quantitative analysis was performed by subdividing the imaged graft into three major regions and selecting a reference region from eithermore » the native aorta or common iliac artery. Excess platelet deposition was determined by two methods: 1) the ratio of In-111 counts in the graft ROI''s to the reference region and 2) the percent In-111 excess using the Tc99m blood pool subtraction technique (TBPST). Animals were sacrificed 7 weeks after implantation and radioactivity in the excised grafts was determined using a well counter. A positive correlation was found to exist between the In-111 ratio percent analysis (IRPA) and the direct gamma counting (DCC) for all three segments of the prosthetic graft. Correlation coefficients for the thorax, midsegment and abdominal segments were 0.80, 0.73 and 0.48 respectivly. There was no correlation between TBPST and DGC. Using the IRPA technique the thrombogenicity of TAG's can be routinely assessed and is clinically applicable for patient use. TBPST should probably be limited to the extremities to avoid error due to free Tc99m counts from kidneys and ureters.« less

Landscape moderation of biodiversity patterns and processes - eight hypotheses.

PubMed

Tscharntke, Teja; Tylianakis, Jason M; Rand, Tatyana A; Didham, Raphael K; Fahrig, Lenore; Batáry, Péter; Bengtsson, Janne; Clough, Yann; Crist, Thomas O; Dormann, Carsten F; Ewers, Robert M; Fründ, Jochen; Holt, Robert D; Holzschuh, Andrea; Klein, Alexandra M; Kleijn, David; Kremen, Claire; Landis, Doug A; Laurance, William; Lindenmayer, David; Scherber, Christoph; Sodhi, Navjot; Steffan-Dewenter, Ingolf; Thies, Carsten; van der Putten, Wim H; Westphal, Catrin

2012-08-01

Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which we hope will encourage more systematic research on the role of landscape composition and configuration in determining the structure of ecological communities, ecosystem functioning and services. We organize the eight hypotheses under four overarching themes. Section A: 'landscape moderation of biodiversity patterns' includes (1) the landscape species pool hypothesis-the size of the landscape-wide species pool moderates local (alpha) biodiversity, and (2) the dominance of beta diversity hypothesis-landscape-moderated dissimilarity of local communities determines landscape-wide biodiversity and overrides negative local effects of habitat fragmentation on biodiversity. Section B: 'landscape moderation of population dynamics' includes (3) the cross-habitat spillover hypothesis-landscape-moderated spillover of energy, resources and organisms across habitats, including between managed and natural ecosystems, influences landscape-wide community structure and associated processes and (4) the landscape-moderated concentration and dilution hypothesis-spatial and temporal changes in landscape composition can cause transient concentration or dilution of populations with functional consequences. Section C: 'landscape moderation of functional trait selection' includes (5) the landscape-moderated functional trait selection hypothesis-landscape moderation of species trait selection shapes the functional role and trajectory of community assembly, and (6) the landscape-moderated insurance hypothesis-landscape complexity provides spatial and temporal insurance, i.e. high resilience and stability of ecological processes in changing environments. Section D: 'landscape constraints on conservation management' includes (7) the intermediate landscape-complexity hypothesis-landscape-moderated effectiveness of local conservation management is highest in structurally simple, rather than in cleared (i.e. extremely simplified) or in complex landscapes, and (8) the landscape-moderated biodiversity versus ecosystem service management hypothesis-landscape-moderated biodiversity conservation to optimize functional diversity and related ecosystem services will not protect endangered species. Shifting our research focus from local to landscape-moderated effects on biodiversity will be critical to developing solutions for future biodiversity and ecosystem service management. © 2012 The Authors. Biological Reviews © 2012 Cambridge Philosophical Society.

Non-Markovian near-infrared Q branch of HCl diluted in liquid Ar.

PubMed

Padilla, Antonio; Pérez, Justo

2013-08-28

By using a non-Markovian spectral theory based in the Kubo cumulant expansion technique, we have qualitatively studied the infrared Q branch observed in the fundamental absorption band of HCl diluted in liquid Ar. The statistical parameters of the anisotropic interaction present in this spectral theory were calculated by means of molecular dynamics techniques, and found that the values of the anisotropic correlation times are significantly greater (by a factor of two) than those previously obtained by fitting procedures or microscopic cell models. This fact is decisive for the observation in the theoretical spectral band of a central Q resonance which is absent in the abundant previous researches carried out with the usual theories based in Kubo cumulant expansion techniques. Although the theory used in this work only allows a qualitative study of the Q branch, we can employ it to study the unknown characteristics of the Q resonance which are difficult to obtain with the quantum simulation techniques recently developed. For example, in this study we have found that the Q branch is basically a non-Markovian (or memory) effect produced by the spectral line interferences, where the PR interferential profile basically determines the Q branch spectral shape. Furthermore, we have found that the Q resonance is principally generated by the first rotational states of the first two vibrational levels, those more affected by the action of the dissolvent.

Comparison of Acid Titration, Conductivity, Flame Photometry, ICP-MS, and Accelerated Lamellae Formation Techniques in Determining Glass Vial Quality.

PubMed

Fujimori, Kiyoshi; Lee, Hans; Sloey, Christopher; Ricci, Margaret S; Wen, Zai-Qing; Phillips, Joseph; Nashed-Samuel, Yasser

2016-01-01

Certain types of glass vials used as primary containers for liquid formulations of biopharmaceutical drug products have been observed with delamination that produced small glass like flakes termed lamellae under certain conditions during storage. The cause of this delamination is in part related to the glass surface defects, which renders the vials susceptible to flaking, and lamellae are formed during the high-temperature melting and annealing used for vial fabrication and shaping. The current European Pharmacopoeia method to assess glass vial quality utilizes acid titration of vial extract pools to determine hydrolytic resistance or alkalinity. Four alternative techniques with improved throughput, convenience, and/or comprehension were examined by subjecting seven lots of vials to analysis by all techniques. The first three new techniques of conductivity, flame photometry, and inductively coupled plasma mass spectrometry measured the same sample pools as acid titration. All three showed good correlation with alkalinity: conductivity (R(2) = 0.9951), flame photometry sodium (R(2) = 0.9895), and several elements by inductively coupled plasma mass spectrometry [(sodium (R(2) = 0.9869), boron (R(2) = 0.9796), silicon (R(2) = 0.9426), total (R(2) = 0.9639)]. The fourth technique processed the vials under conditions that promote delamination, termed accelerated lamellae formation, and then inspected those vials visually for lamellae. The visual inspection results without the lot with different processing condition correlated well with alkalinity (R(2) = 0.9474). Due to vial processing differences affecting alkalinity measurements and delamination propensity differently, the ratio of silicon and sodium measurements from inductively coupled plasma mass spectrometry was the most informative technique to assess overall vial quality and vial propensity for lamellae formation. The other techniques of conductivity, flame photometry, and accelerated lamellae formation condition may still be suitable for routine screening of vial lots produced under consistent processes. Recently, delamination that produced small glass like flakes termed lamellae has been observed in glass vials that are commonly used as primary containers for pharmaceutical drug products under certain conditions during storage. The main cause of these lamellae was the quality of the glass itself related to the manufacturing process. Current European Pharmacopoeia method to assess glass vial quality utilizes acid titration of vial extract pools to determine hydrolytic resistance or alkalinity. As alternative to the European Pharmacopoeia method, four other techniques were assessed. Three new techniques of conductivity, flame photometry, and inductively coupled plasma mass spectrometry measured the vial extract pool as acid titration to quantify quality, and they demonstrated good correlation with original alkalinity. The fourth technique processed the vials under conditions that promote delamination, termed accelerated lamellae formation, and the vials were then inspected visually for lamellae. The accelerated lamellae formation technique also showed good correlation with alkalinity. Of the new four techniques, inductively coupled plasma mass spectrometry was the most informative technique to assess overall vial quality even with differences in processing between vial lots. Other three techniques were still suitable for routine screening of vial lots produced under consistent processes. © PDA, Inc. 2016.

Drinking behaviour and water turnover rates of Antarctic fur seal pups: implications for the estimation of milk intake by isotopic dilution.

PubMed

Lea, Mary-Anne; Bonadonna, Francesco; Hindell, Mark A; Guinet, Christophe; Goldsworthy, Simon D

2002-06-01

The estimation of milk consumption in free-ranging seals using tritium dilution techniques makes the key assumption that the animals drink no pre-formed water during the experimental period. However, frequent observations of unweaned Antarctic fur seal pups drinking water at Iles Kerguelen necessitated the testing of this assumption. We estimated water flux rates of 30 pups (10.7+/-0.3 kg) in four experimental groups by isotopic dilution over 4 days. The groups were: (1) pups held in an open air enclosure without access to water to estimate fasting metabolic water production (MWP); (2) free-ranging pups not administered additional water; (3) pups held in an open air enclosure and given a total of 300 ml of fresh water to verify technique accuracy; and (4) free-ranging pups given 200 ml of fresh water. Pups without access to water exhibited water flux rates (20.5+/-0.8 ml kg(-1)d(-1)), which were significantly lower than those observed for the free-ranging group (33.0+/-1.7 ml kg(-1) d(-1)). Mean estimated pre-formed water intake for the free-ranging experimental groups was 12.6 ml kg(-1) d(-1). Thus, MWP, measured as total water intake during fasting, may be significantly over-estimated in free-ranging Antarctic fur seal pups at Iles Kerguelen and at other sites and subsequently milk intake rates may be underestimated.

Revitalizing Higher Education. The Stanford Forum for Higher Education Futures.

ERIC Educational Resources Information Center

Meyerson, Joel W., Ed.; Massy, William F., Ed.

This volume contains six essays on higher education which provide lessons and successful techniques for meeting the challenges of the future. The first essay, "Academic Renewal at Michigan" (James Duderstadt), describes the modern research university as a complex corporate conglomerate in danger of diluting its core business. The…

Influence of carotene-rich vegetable meals on the prevalence of anaemia and iron deficiency in Filipino schoolchildren.

PubMed

Maramag, C C; Ribaya-Mercado, J D; Rayco-Solon, P; Solon, J A A; Tengco, L W; Blumberg, J B; Solon, F S

2010-05-01

To determine the effects of eating carotene-rich green and yellow vegetables on the prevalence of anaemia, iron deficiency and iron-deficiency anaemia in schoolchildren. Schoolchildren (n=104), aged 9-12 years, received standardized meals containing 4.2 mg of provitamin A carotenoids/day (mainly beta-carotene) from yellow and green leafy vegetables and at least 7 g dietary fat/day. The meals were provided three times/day, 5 days/week, for 9 weeks at school. Before and after the dietary intervention, total-body vitamin A pool size was assessed by using the deuterated-retinol-dilution method; serum retinol and beta-carotene concentrations were measured by high-performance liquid chromatography; and whole blood haemoglobin (Hb) and zinc protoporphyrin (ZnPP) concentrations were measured by using a photometer and a hematofluorometer, respectively. After 9 weeks, the mean total-body vitamin A pool size increased twofold (95% confidence interval (CI): -0.11, -0.07 micromol retinol; P<0.001), and serum beta-carotene concentration increased fivefold (95% CI: -0.97, -0.79 micromol/l; P<0.001). Blood Hb (95% CI: -1.02, -0.52 g per 100 ml; P<0.001) and ZnPP increased (95% CI: -11.82, -4.57 microol/mol haem; P<0.001). The prevalence of anaemia (Hb<11.5 g per 100 ml) decreased from 12.5 to 1.9% (P<0.001). There were no significant changes in the prevalence of iron deficiency or iron-deficiency anaemia. Ingestion of carotene-rich yellow and green leafy vegetables improves the total-body vitamin A pool size and Hb concentration, and decreases anaemia rates in Filipino schoolchildren, with no effect on iron deficiency or iron-deficiency anaemia rates.

Analytical and numerical studies of photo-injected charge transport in molecularly-doped polymers

NASA Astrophysics Data System (ADS)

Roy Chowdhury, Amrita

The mobility of photo-injected charge carriers in molecularly-doped polymers (MDPs) exhibits a commonly observed, and nearly universal Poole-Frenkel field dependence, mu exp√(beta0E), that has been shown to arise from the correlated Gaussian energy distribution of transport sites encountered by charges undergoing hopping transport through the material. Analytical and numerical studies of photo-injected charge transport in these materials are presented here with an attempt to understand how specific features of the various models developed to describe these systems depend on the microscopic parameters that define them. Specifically, previously published time-of-flight mobility data for the molecularly doped polymer 30% DEH:PC (polycarbonate doped with 30 wt.% aromatic hydrazone DEH) is compared with direct analytical and numerical predictions of five disorder-based models, the Gaussian disorder model (GDM) of Bassler, and four correlated disorder models introduced by Novikov, et al., and by Parris, et al. In these numerical studies, disorder parameters describing each model were varied from reasonable starting conditions, in order to give the best overall fit. The uncorrelated GDM describes the Poole-Frenkel field dependence of the mobility only at very high fields, but fails for fields lower than about 64 V/mum. The correlated disorder models with small amounts of geometrical disorder do a good over-all job of reproducing a robust Poole-Frenkel field dependence, with correlated disorder theories that employ polaron transition rates showing qualitatively better agreement with experiment than those that employ Miller-Abrahams rates. In a separate study, the heuristic treatment of spatial or geometric disorder incorporated in existing theories is critiqued, and a randomly-diluted lattice gas model is developed to describe the spatial disorder of the transport sites in a more realistic way.

Cross-sectional biomonitoring study of pesticide exposures in Queensland, Australia, using pooled urine samples.

PubMed

Heffernan, A L; English, K; Toms, Lml; Calafat, A M; Valentin-Blasini, L; Hobson, P; Broomhall, S; Ware, R S; Jagals, P; Sly, P D; Mueller, J F

2016-12-01

A range of pesticides are available in Australia for use in agricultural and domestic settings to control pests, including organophosphate and pyrethroid insecticides, herbicides, and insect repellents, such as N,N-diethyl-meta-toluamide (DEET). The aim of this study was to provide a cost-effective preliminary assessment of background exposure to a range of pesticides among a convenience sample of Australian residents. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n = 24 pools of 100 specimens). Concentrations of urinary pesticide biomarkers were quantified using solid-phase extraction coupled with isotope dilution high-performance liquid chromatography-tandem mass spectrometry. Geometric mean biomarker concentrations ranged from <0.1 to 36.8 ng/mL for organophosphate insecticides, <0.1 to 5.5 ng/mL for pyrethroid insecticides, and <0.1 to 8.51 ng/mL for all other biomarkers with the exception of the DEET metabolite 3-diethylcarbamoyl benzoic acid (4.23 to 850 ng/mL). We observed no association between age and concentration for most biomarkers measured but noted a "U-shaped" trend for five organophosphate metabolites, with the highest concentrations observed in the youngest and oldest age strata, perhaps related to age-specific differences in behavior or physiology. The fact that concentrations of specific and non-specific metabolites of the organophosphate insecticide chlorpyrifos were higher than reported in USA and Canada may relate to differences in registered applications among countries. Additional biomonitoring programs of the general population and focusing on vulnerable populations would improve the exposure assessment and the monitoring of temporal exposure trends as usage patterns of pesticide products in Australia change over time.

Finding the joker among the maize endogenous reference genes for genetically modified organism (GMO) detection.

PubMed

Paternò, Annalisa; Marchesi, Ugo; Gatto, Francesco; Verginelli, Daniela; Quarchioni, Cinzia; Fusco, Cristiana; Zepparoni, Alessia; Amaddeo, Demetrio; Ciabatti, Ilaria

2009-12-09

The comparison of five real-time polymerase chain reaction (PCR) methods targeted at maize ( Zea mays ) endogenous sequences is reported. PCR targets were the alcohol dehydrogenase (adh) gene for three methods and high-mobility group (hmg) gene for the other two. The five real-time PCR methods have been checked under repeatability conditions at several dilution levels on both pooled DNA template from several genetically modified (GM) maize certified reference materials (CRMs) and single CRM DNA extracts. Slopes and R(2) coefficients of all of the curves obtained from the adopted regression model were compared within the same method and among all of the five methods, and the limit of detection and limit of quantitation were analyzed for each PCR system. Furthermore, method equivalency was evaluated on the basis of the ability to estimate the target haploid genome copy number at each concentration level. Results indicated that, among the five methods tested, one of the hmg-targeted PCR systems can be considered equivalent to the others but shows the best regression parameters and a higher repeteability along the dilution range. Thereby, it is proposed as a valid module to be coupled to different event-specific real-time PCR for maize genetically modified organism (GMO) quantitation. The resulting practicability improvement on the analytical control of GMOs is discussed.

T1 relaxivity of core-encapsulated gadolinium liposomal contrast agents--effect of liposome size and internal gadolinium concentration.

PubMed

Ghaghada, Ketan; Hawley, Catherine; Kawaji, Keigo; Annapragada, Ananth; Mukundan, Srinivasan

2008-10-01

Long circulating core-encapsulated gadolinium (CE-Gd) liposomal nanoparticles that have surface conjugated polyethylene glycol are a promising platform technology for use as blood pool T1-based magnetic resonance (MR) contrast agents. The objective of this study was to investigate the effect of liposome size and internal (core) Gd concentration on the T1 relaxivity of CE-Gd liposomes. Twelve different liposomal formulations were synthesized and characterized, resulting in a size (50, 100, 200, and 400 nm) and core Gd-concentration (200, 350, and 500 mM) "matrix" of test samples. Subsequently, CE-Gd liposomes were diluted in deionized water (four diluted samples) and molar T1 relaxivity (r1) measurements were performed at 2- and 7-T MR field strengths. The r1 of CE-Gd liposomes was inversely related to the liposome size. The largest change in r1 was observed between liposomes that were extruded through 50- and 100-nm filter membranes. At both field strengths, the variation in internal gadolinium concentration did not show any significant correlation (alpha < or = 0.05) with r1. The size of CE-Gd liposomal nanoparticles significantly affects the T1 relaxivity. An inverse relation was observed between liposome size and T1 relaxivity. The T1 relaxivity did not change significantly with core Gd concentration over the measured concentration range.

Comparison of plethysmographic and helium dilution lung volumes in patients with a giant emphysematous bulla as selection criteria for endobronchial valve implant.

PubMed

Fiorelli, Alfonso; Scaramuzzi, Roberto; Pierdiluca, Matteo; Frongillo, Elisabetta; Messina, Gaetana; Serra, Nicola; De Felice, Alberto; Santini, Mario

2017-09-01

To assess whether the difference in lung volume measured with plethysmography and with the helium dilution technique could differentiate an open from a closed bulla in patients with a giant emphysematous bulla and could be used as a selection criterion for the positioning of an endobronchial valve. We reviewed the data of 27 consecutive patients with a giant emphysematous bulla undergoing treatment with an endobronchial valve. In addition to standard functional and radiological examinations, total lung capacity and residual volume were measured with the plethysmographic and helium dilution technique. We divided the patients into 2 groups, the collapse or the no-collapse group, depending on whether the bulla collapsed or not after the valves were put in position. We statistically evaluated the intergroup differences in lung volume and outcome. In the no-collapse group (n = 6), the baseline plethysmographic values were significantly higher than the helium dilution volumes, including total lung capacity (188 ± 14 vs 145 ± 13, P = 0.0007) and residual volume (156 ± 156 vs 115 ± 15, P = 0.001). In the collapse group, there was no significant difference in lung volumes measured with the 2 methods. A difference in total lung capacity of ≤ 13% and in residual volume of ≤ 25% measured with the 2 methods predicted the collapse of the bulla with a success rate of 83% and 84%, respectively. Only the collapse group showed significant improvement in functional data. Similar values in lung volumes measured with the 2 methods support the hypothesis that the bulla communicates with the airway (open bulla) and thus is likely to collapse when the endobronchial valve is implanted. Further studies are needed to validate our model. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Low temperature deposition of nanocrystalline silicon carbide films by plasma enhanced chemical vapor deposition and their structural and optical characterization

NASA Astrophysics Data System (ADS)

Rajagopalan, T.; Wang, X.; Lahlouh, B.; Ramkumar, C.; Dutta, Partha; Gangopadhyay, S.

2003-10-01

Nanocrystalline silicon carbide (SiC) thin films were deposited by plasma enhanced chemical vapor deposition technique at different deposition temperatures (Td) ranging from 80 to 575 °C and different gas flow ratios (GFRs). While diethylsilane was used as the source for the preparation of SiC films, hydrogen, argon and helium were used as dilution gases in different concentrations. The effects of Td, GFR and dilution gases on the structural and optical properties of these films were investigated using high resolution transmission electron microscope (HRTEM), micro-Raman, Fourier transform infrared (FTIR) and ultraviolet-visible optical absorption techniques. Detailed analysis of the FTIR spectra indicates the onset of formation of SiC nanocrystals embedded in the amorphous matrix of the films deposited at a temperature of 300 °C. The degree of crystallization increases with increasing Td and the crystalline fraction (fc) is 65%±2.2% at 575 °C. The fc is the highest for the films deposited with hydrogen dilution in comparison with the films deposited with argon and helium at the same Td. The Raman spectra also confirm the occurrence of crystallization in these films. The HRTEM measurements confirm the existence of nanocrystallites in the amorphous matrix with a wide variation in the crystallite size from 2 to 10 nm. These results are in reasonable agreement with the FTIR and the micro-Raman analysis. The variation of refractive index (n) with Td is found to be quite consistent with the structural evolution of these films. The films deposited with high dilution of H2 have large band gap (Eg) and these values vary from 2.6 to 4.47 eV as Td is increased from 80 to 575 °C. The size dependent shift in the Eg value has also been investigated using effective mass approximation. Thus, the observed large band gap is attributed to the presence of nanocrystallites in the films.

Experimental Studies on role of pH, potential and concentration of buffer solution for chemical bath deposition technique

NASA Astrophysics Data System (ADS)

Suresha, B. L.; Sumantha, H. S.; Salman, K. Mohammed; Pramod, N. G.; Abhiram, J.

2018-04-01

The ionization potential is usually found to be less in acid and more in base. The experiment proves that the ionization potential increases on dilution of acid to base and reduces from base to acid. The potential can be tailored according to the desired properties based on our choice of acid or base. The experimental study establishes a direct relationship between pH and electric potential. This work provides theoretical insights on the need for a basic media of pH 10 in chemical thin film growth techniques called Chemical Bath Deposition Techniques.

Nearest Neighbor Searching in Binary Search Trees: Simulation of a Multiprocessor System.

ERIC Educational Resources Information Center

Stewart, Mark; Willett, Peter

1987-01-01

Describes the simulation of a nearest neighbor searching algorithm for document retrieval using a pool of microprocessors. Three techniques are described which allow parallel searching of a binary search tree as well as a PASCAL-based system, PASSIM, which can simulate these techniques. Fifty-six references are provided. (Author/LRW)

Genomic screening for blood-borne viruses in transfusion settings.

PubMed

Allain, J P

2000-02-01

The residual risk of post-transfusion human immunodeficiency virus (HIV) infection is low but slightly higher for hepatitis B virus (HBV) and hepatitis C virus (HCV), the main reason being viraemia during the window period preceding antibody or antigen detection by enzyme immunoassays. Immunosilent-infected individuals and carriers of distant viral variants also play an unquantifiable role. Multiple techniques, e.g. reverse transcription-polymerase chain reaction (RT-PCR), PCR, ligase-chain reaction, nucleic acid sequence-based amplification (NASBA) and transcription-mediated amplification (TMA) have been developed to amplify and detect viral genomes as single or multiplex assays. Equipment providing various degrees of automation has been adapted to these techniques. Applying nucleic acid amplification techniques (NAT) to blood screening, two main approaches have been advocated: plasma pool and single-donation testing. Pool testing presents the advantage of lower cost and readily available equipment although it is prone to false negative and positive reactions. The time required to identify infected donations is incompatible with blood component release, and may lead to product waste. Single-unit testing, although appealing, is not yet fully automated and potentially very costly unless a systematic multiplex approach is taken. Although technically feasible, NAT applied to the blood supply needs to be clinically evaluated and its cost efficiency assessed in the general public health context. However, pool NAT is currently implemented in continental Europe and the USA.

Steady-state MRA techniques with a blood pool contrast agent improve visualization of pulmonary venous anatomy and left atrial patency compared with time-resolved MRA pre- and postcatheter ablation in atrial fibrillation.

PubMed

Rustogi, Rahul; Galizia, Mauricio; Thakrar, Darshit; Merritt, Bryce; Bi, Xiaoming; Collins, Jeremy; Carr, James C

2015-11-01

To compare steady-state magnetic resonance angiography (SS-MRA), using a blood pool contrast agent, with the established technique of time-resolved MRA (TR-MRA), in pulmonary vein mapping and left atrial patency. Twenty-one patients (12 males, age 58.3 ± 8.4 years; 9 females; 57 ± 10 years) undergoing pulmonary vein mapping were evaluated with TR-MRA (TWIST) and SS-MRA. Orthogonal measurements and areas for four veins per patient per technique were assessed by Friedman's test. Overall intertechnique mean difference for any pulmonary vein orthogonal measurement and area was 0.02 ± 0.34 cm (P = 0.705), and 0.2 ± 0.08 cm(2) (P < 0.001). Interobserver correlation was strong for diameter and area measurements using the three methods with a range of 0.72-0.94, and 0.87-0.97, respectively. Left atrial appendage image quality score for TR-MRA was significantly lower than the other two methods (P < 0.001). Both observers detected more stenosis on inversion recovery (IR)-True FISP compared to TR-MRA and IR-FLASH. SS-MRA with a blood pool agent compared favorably to the established technique of TR-MRA for quantitative assessment of pulmonary venous anatomy. SS-MRA offers greater spatial resolution than TR-MRA with increased confidence for ruling out left atrial appendage filling defect. © 2015 Wiley Periodicals, Inc.

The palisade cartilage tympanoplasty technique: a systematic review and meta-analysis.

PubMed

Jeffery, Caroline C; Shillington, Cameron; Andrews, Colin; Ho, Allan

2017-06-17

Tympanoplasty is a common procedure performed by Otolaryngologists. Many types of autologous grafts have been used with variations of techniques with varying results. This is the first systematic review of the literature and meta-analysis with the aim to evaluate the effectiveness of one of the techniques which is gaining popularity, the palisade cartilage tympanoplasty. PubMed, EMBASE, and Cochrane databases were searched for "palisade", "cartilage", "tympanoplasty", "perforation" and their synonyms. In total, 199 articles reporting results of palisade cartilage tympanoplasty were identified. Five articles satisfied the following inclusion criteria: adult patients, minimum 6 months follow-up, hearing and surgical outcomes reported. Studies with patients undergoing combined mastoidectomy, ossicular chain reconstruction, and/or other middle ear surgery were excluded. Perforation closure, rate of complications, and post-operative pure-tone average change were extracted for pooled analysis. Study failure and complication proportions that were used to generate odds ratios were pooled. Fixed effects and random effects weightings were generated. The resulting pooled odds ratios are reported. Palisade cartilage tympanoplasty has an overall take rate of 96% at beyond 6 months and has similar odds of complications compared to temporalis fascia (OR 0.89, 95% CI 0.62, 1.30). The air-bone gap closure is statistically similar to reported results from temporalis fascia tympanoplasty. Cartilage palisade tympanoplasty offers excellent graft take rates and good postoperative hearing outcomes for perforations of various sizes and for both primary and revision cases. This technique has predictable, long-term results with low complication rates, similar to temporalis fascia tympanoplasty.

Dilution correction equation revisited: The impact of stream slope, relief ratio and area size of basin on geochemical anomalies

NASA Astrophysics Data System (ADS)

Shahrestani, Shahed; Mokhtari, Ahmad Reza

2017-04-01

Stream sediment sampling is a well-known technique used to discover the geochemical anomalies in regional exploration activities. In an upstream catchment basin of stream sediment sample, the geochemical signals originating from probable mineralization could be diluted due to mixing with the weathering material coming from the non-anomalous sources. Hawkes's equation (1976) was an attempt to overcome the problem in which the area size of catchment basin was used to remove dilution from geochemical anomalies. However, the metal content of a stream sediment sample could be linked to several geomorphological, sedimentological, climatic and geological factors. The area size is not itself a comprehensive representative of dilution taking place in a catchment basin. The aim of the present study was to consider a number of geomorphological factors affecting the sediment supply, transportation processes, storage and in general, the geochemistry of stream sediments and their incorporation in the dilution correction procedure. This was organized through employing the concept of sediment yield and sediment delivery ratio and linking such characteristics to the dilution phenomenon in a catchment basin. Main stream slope (MSS), relief ratio (RR) and area size (Aa) of catchment basin were selected as the important proxies (PSDRa) for sediment delivery ratio and then entered to the Hawkes's equation. Then, Hawkes's and new equations were applied on the stream sediment dataset collected from Takhte-Soleyman district, west of Iran for Au, As and Sb values. A number of large and small gold, antimony and arsenic mineral occurrences were used to evaluate the results. Anomaly maps based on the new equations displayed improvement in anomaly delineation taking the spatial distribution of mineral deposits into account and could present new catchment basins containing known mineralization as the anomaly class, especially in the case of Au and As. Four catchment basins having Au and As mineralization were added to anomaly class and also one catchment basin with known As occurrence was highlighted as anomalous using new approach. The results demonstrated the usefulness of considering geomorphological parameters in dealing with dilution phenomenon in a catchment basin.

Rhenium-osmium isotope systematics in meteorites. I - Magmatic iron meteorite groups IIAB and IIIAB

NASA Technical Reports Server (NTRS)

Morgan, John W.; Walker, Richard J.; Grossman, Jeffery N.

1992-01-01

Resonance ionization mass spectrometry is used to determine the Re and Os abundances by isotope dilution (ID) and to measure Os-187/Os-186 ratios from 19 iron meteorites. Abundances range from 1.4 to 4800 ppb Re, and from 13 to 65,000 ppb Os, and generally agree well with previous ID and neutron activation results. The Re and Os data suggest that abundance trends in these iron groups may be entirely explained by fractional crystallization. Whole-rock isochrons for the IIAB and IIIAB groups are statistically indistinguishable. Pooled data yield an initial Os-187/Os-186 of 0.794 +/- 0.010 Ga. Given the errors in the slope and half life, this age does not differ significantly from the canonical chondrite age of 4.56 Ga, but could be as young as 4.46 Ga.

Magneto-optical detection of the relaxation dynamics of alloy nanoparticles with a high-stability magnetic circular dichroism setup

NASA Astrophysics Data System (ADS)

Cavigli, L.; de Julián Fernández, C.; Gatteschi, D.; Gurioli, M.; Sangregorio, C.; Mattei, G.; Mazzoldi, P.; Bogani, L.

2007-09-01

We present a versatile high-stability and high-sensitivity magneto-optical setup that allows transmission and reflection measurements at high fields and low temperatures. We apply the technique to measure the decay in time of the magnetization of highly monodisperse 3.3 nm Co33Ni67 alloy nanoparticles embedded in a silica host. We demonstrate the possibility of observing the dynamics of the magnetization over a macroscopic timescale in dilute samples, where other techniques are unavailable.

Optical penetration sensor for pulsed laser welding

DOEpatents

Essien, Marcelino; Keicher, David M.; Schlienger, M. Eric; Jellison, James L.

2000-01-01

An apparatus and method for determining the penetration of the weld pool created from pulsed laser welding and more particularly to an apparatus and method of utilizing an optical technique to monitor the weld vaporization plume velocity to determine the depth of penetration. A light source directs a beam through a vaporization plume above a weld pool, wherein the plume changes the intensity of the beam, allowing determination of the velocity of the plume. From the velocity of the plume, the depth of the weld is determined.

Bit-serial neuroprocessor architecture

NASA Technical Reports Server (NTRS)

Tawel, Raoul (Inventor)

2001-01-01

A neuroprocessor architecture employs a combination of bit-serial and serial-parallel techniques for implementing the neurons of the neuroprocessor. The neuroprocessor architecture includes a neural module containing a pool of neurons, a global controller, a sigmoid activation ROM look-up-table, a plurality of neuron state registers, and a synaptic weight RAM. The neuroprocessor reduces the number of neurons required to perform the task by time multiplexing groups of neurons from a fixed pool of neurons to achieve the successive hidden layers of a recurrent network topology.

ASCAN Ochoa floats in pool during Elgin AFB water survival training

NASA Technical Reports Server (NTRS)

1990-01-01

1990 Group 13 Astronaut Candidate (ASCAN) Ellen Ochoa, wearing helmet and flight suit, climbs into a single person life raft while floating in a pool at Elgin Air Force Base (AFB) in Pensacola, Florida, during water survival exercises. Ochoa's underarm flotation device holds her above the water as she pulls herself into the life raft. The training familiarized the candidates with survival techniques necessary in the event of a water landing. ASCANs participated in the exercises from 08-14-90 through 08-17-90.

High-concentration zeta potential measurements using light-scattering techniques

PubMed Central

Kaszuba, Michael; Corbett, Jason; Watson, Fraser Mcneil; Jones, Andrew

2010-01-01

Zeta potential is the key parameter that controls electrostatic interactions in particle dispersions. Laser Doppler electrophoresis is an accepted method for the measurement of particle electrophoretic mobility and hence zeta potential of dispersions of colloidal size materials. Traditionally, samples measured by this technique have to be optically transparent. Therefore, depending upon the size and optical properties of the particles, many samples will be too concentrated and will require dilution. The ability to measure samples at or close to their neat concentration would be desirable as it would minimize any changes in the zeta potential of the sample owing to dilution. However, the ability to measure turbid samples using light-scattering techniques presents a number of challenges. This paper discusses electrophoretic mobility measurements made on turbid samples at high concentration using a novel cell with reduced path length. Results are presented on two different sample types, titanium dioxide and a polyurethane dispersion, as a function of sample concentration. For both of the sample types studied, the electrophoretic mobility results show a gradual decrease as the sample concentration increases and the possible reasons for these observations are discussed. Further, a comparison of the data against theoretical models is presented and discussed. Conclusions and recommendations are made from the zeta potential values obtained at high concentrations. PMID:20732896

Novel method for immunofluorescence staining of mammalian eggs using non-contact alternating-current electric-field mixing of microdroplets

PubMed Central

Hiromitsu, Shirasawa; Jin, Kumagai; Emiko, Sato; Katsuya, Kabashima; Yukiyo, Kumazawa; Wataru, Sato; Hiroshi, Miura; Ryuta, Nakamura; Hiroshi, Nanjo; Yoshihiro, Minamiya; Yoichi, Akagami; Yukihiro, Terada

2015-01-01

Recently, a new technique was developed for non-catalytically mixing microdroplets. In this method, an alternating-current (AC) electric field is used to promote the antigen–antibody reaction within the microdroplet. Previously, this technique has only been applied to histological examinations of flat structures, such as surgical specimens. In this study, we applied this technique for the first time to immunofluorescence staining of three-dimensional structures, specifically, mammalian eggs. We diluted an antibody against microtubules from 1:1,000 to 1:16,000, and compared the chromatic degree and extent of fading across dilutions. In addition, we varied the frequency of AC electric-field mixing from 5 Hz to 46 Hz and evaluated the effect on microtubule staining. Microtubules were more strongly stained after AC electric-field mixing for only 5 minutes, even when the concentration of primary antibody was 10 times lower than in conventional methods. AC electric-field mixing also alleviated microtubule fading. At all frequencies tested, AC electric-field mixing resulted in stronger microtubule staining than in controls. There was no clear difference in a microtubule staining between frequencies. These results suggest that the novel method could reduce antibody consumption and shorten immunofluorescence staining time. PMID:26477850

[Keratinophilic fungi in soils of parks of Corrientes city, Argentina].

PubMed

Sarmiento, María Mercedes; Mangiaterra, Magdalena; Bojanich, María Viviana; Basualdo, Juan Ángel; Giusiano, Gustavo

2016-01-01

The soil is a natural reservoir of keratinophilic fungi, which are a small but important group of filamentous fungi, some of which typically develop on keratinized tissues of living animals. There are numerous species of saprophytic fungi with recognized keratinophilic abilities, and several studies have been undertaken in order to link their presence to possible human disease. To know the biota of geophilic fungi in general and of keratinophilic fungi particularly in soils from two public parks. Soil samples from two public parks of Corrientes city, Argentina, were studied during two seasons, using the hook technique and serial dilutions for fungal isolation. Using the hook technique, 170 isolates were classified into 17 genera and 21 species, among which it is worth mentioning the presence of Microsporum canis. Shannon index for keratinophilic fungi in autumn was 2.27, and 1.92 in spring. By means of the serial dilutions technique, 278 fungi isolated were identified into 33 genera and 71 species. Shannon index in autumn was 3.9, and 3.5 in spring. The soils studied have particularly favorable conditions for the survival of pathogens and opportunistic geophilic fungi for humans and animals. Copyright © 2014 Asociación Española de Micología. Published by Elsevier Espana. All rights reserved.

Guideline on Isotope Dilution Mass Spectrometry

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

Gaffney, Amy

Isotope dilution mass spectrometry is used to determine the concentration of an element of interest in a bulk sample. It is a destructive analysis technique that is applicable to a wide range of analytes and bulk sample types. With this method, a known amount of a rare isotope, or ‘spike’, of the element of interest is added to a known amount of sample. The element of interest is chemically purified from the bulk sample, the isotope ratio of the spiked sample is measured by mass spectrometry, and the concentration of the element of interest is calculated from this result. Thismore » method is widely used, although a mass spectrometer required for this analysis may be fairly expensive.« less

Low temperature anomaly of light stimulated magnetization and heat capacity of the 1D diluted magnetic semiconductors

NASA Astrophysics Data System (ADS)

Geffe, Chernet Amente

2018-03-01

This article reports magnetization and specific heat capacity anomalies in one dimensional diluted magnetic semiconductors observed at very low temperatures. Based on quantum field theory double time temperature dependent Green function technique is employed to evaluate magnon dispersion and the time correlation function. It is understood that magnon-photon coupling and magnetic impurity concentration controls both, such that near absolute temperature magnetization is nearly zero and abruptly increase to saturation level with decreasing magnon-photon coupling strength. We also found out dropping of magnetic specific heat capacity as a result of increase in magnetic impurity concentration x, perhaps because of inter-band disorder that would suppress the enhancement of density of spin waves.

Lability of Cd, Cu, and Zn in polluted soils treated with lime, beringite, and red mud and identification of a non-labile colloidal fraction of metals using istopic techniques.

PubMed

Lombi, Enzo; Hamon, Rebecca E; McGrath, Steve P; McLaughlin, Mike J

2003-03-01

The use of soil amendments has been proposed as a low input alternative for the remediation of metal polluted soils. However, little information is available concerning the stability, and therefore the longevity, of the remediation treatments when important soil parameters change. In this paper we investigate the effect of pH changes on the lability of heavy metals in soils treated with lime, beringite, and red mud using a modified isotopic dilution technique in combination with a stepwise acidification procedure. Significant amounts of nonlabile (fixed) Cu and Zn were found to be associated with colloids <0.2 microm in the solution phase. The results obtained indicated that the mobility of fixed colloidal metals is significant and increases with soil pH. This must be considered because most of the soil amendments are alkaline and increase soil pH. All the soil amendments significantly decreased the lability of Cd, Zn, and Cu in the soils as a whole. However, when the soils were re-acidified, the labile pool of metals increased sharply and in the case of lime and beringite, the lability of the metals was similar, at equal pH, to the untreated soil. In contrast the lability of metals in the red mud treated soils was always smaller than that in the untreated soils across the range of pH values tested. These results suggest that the mechanism of action of lime and beringite is similar and probably related to increased metal adsorption and precipitation of metal hydroxides and carbonates at high pH. In the case of red mud, a combination of pH dependent and independent mechanisms (possibly solid-phase diffusion or migration into micropores) may be responsible for the metal fixation observed.

Possible effect of biotechnology on plant gene pools in Turkey.

PubMed

Demir, Aynur

2015-01-02

The recent rapid developments in biotechnology have made great contributions to the study of plant gene pools. The application of in vitro methods in freeze storage and DNA protection techniques in fast production studies has made major advances. From that aspect, biotechnology is an indispensable means for the protection of plant gene pools, which includes the insurance of sustainable agriculture and development of species. Besides all the positive developments, one of the primary risks posed by the uncontrolled spreading of genetically modified organisms is the possibility for other non-target organisms to be negatively affected. Genes of plant origin should be given priority in this type of studies by taking into consideration such negative effects that may result in disruption of ecological balance and damage to plant genetic pools. Turkey, due to its ecological conditions and history, has a very important position in terms of plant gene pools. This richness ought to be protected without corrupting its natural quality and natural evolution process in order to provide the sources of species that will be required for future sustainable agricultural applications. Thus, attention should be paid to the use of biotechnological methods, which play an important role especially in the protection and use of local and original plant gene pools.

Possible effect of biotechnology on plant gene pools in Turkey

PubMed Central

Demir, Aynur

2015-01-01

The recent rapid developments in biotechnology have made great contributions to the study of plant gene pools. The application of in vitro methods in freeze storage and DNA protection techniques in fast production studies has made major advances. From that aspect, biotechnology is an indispensable means for the protection of plant gene pools, which includes the insurance of sustainable agriculture and development of species. Besides all the positive developments, one of the primary risks posed by the uncontrolled spreading of genetically modified organisms is the possibility for other non-target organisms to be negatively affected. Genes of plant origin should be given priority in this type of studies by taking into consideration such negative effects that may result in disruption of ecological balance and damage to plant genetic pools. Turkey, due to its ecological conditions and history, has a very important position in terms of plant gene pools. This richness ought to be protected without corrupting its natural quality and natural evolution process in order to provide the sources of species that will be required for future sustainable agricultural applications. Thus, attention should be paid to the use of biotechnological methods, which play an important role especially in the protection and use of local and original plant gene pools. PMID:26019612

Determination of melt pool dimensions using DOE-FEM and RSM with process window during SLM of Ti6Al4V powder

NASA Astrophysics Data System (ADS)

Zhuang, Jyun-Rong; Lee, Yee-Ting; Hsieh, Wen-Hsin; Yang, An-Shik

2018-07-01

Selective laser melting (SLM) shows a positive prospect as an additive manufacturing (AM) technique for fabrication of 3D parts with complicated structures. A transient thermal model was developed by the finite element method (FEM) to simulate the thermal behavior for predicting the time evolution of temperature field and melt pool dimensions of Ti6Al4V powder during SLM. The FEM predictions were then compared with published experimental measurements and calculation results for model validation. This study applied the design of experiment (DOE) scheme together with the response surface method (RSM) to conduct the regression analysis based on four processing parameters (exactly, the laser power, scanning speed, preheating temperature and hatch space) for predicting the dimensions of the melt pool in SLM. The preliminary RSM results were used to quantify the effects of those parameters on the melt pool size. The process window was further implemented via two criteria of the width and depth of the molten pool to screen impractical conditions of four parameters for including the practical ranges of processing parameters. The FEM simulations confirmed the good accuracy of the critical RSM models in the predictions of melt pool dimensions for three typical SLM working scenarios.

Techniques for determining total body water using deuterium oxide

NASA Technical Reports Server (NTRS)

Bishop, Phillip A.

1990-01-01

The measurement of total body water (TBW) is fundamental to the study of body fluid changes consequent to microgravity exposure or treatment with microgravity countermeasures. Often, the use of radioactive isotopes is prohibited for safety or other reasons. It was selected and implemented for use by some Johnson Space Center (JCS) laboratories, which permitted serial measurements over a 14 day period which was accurate enough to serve as a criterion method for validating new techniques. These requirements resulted in the selection of deuterium oxide dilution as the method of choice for TBW measurement. The development of this technique at JSC is reviewed. The recommended dosage, body fluid sampling techniques, and deuterium assay options are described.

In-gel multiple displacement amplification of long DNA fragments diluted to the single molecule level.

PubMed

Michikawa, Yuichi; Sugahara, Keisuke; Suga, Tomo; Ohtsuka, Yoshimi; Ishikawa, Kenichi; Ishikawa, Atsuko; Shiomi, Naoko; Shiomi, Tadahiro; Iwakawa, Mayumi; Imai, Takashi

2008-12-15

The isolation and multiple genotyping of long individual DNA fragments are needed to obtain haplotype information for diploid organisms. Limiting dilution of sample DNA followed by multiple displacement amplification is a useful technique but is restricted to short (<5 kb) DNA fragments. In the current study, a novel modification was applied to overcome these problems. A limited amount of cellular DNA was carefully released from intact cells into a mildly heated alkaline agarose solution and mixed thoroughly. The solution was then gently aliquoted and allowed to solidify while maintaining the integrity of the diluted DNA. Exogenously provided Phi29 DNA polymerase was used to perform consistent genomic amplification with random hexameric oligonucleotides within the agarose gels. Simple heat melting of the gel allowed recovery of the amplified materials in a solution of the polymerase chain reaction (PCR)-ready form. The haplotypes of seven SNPs spanning 240 kb of the DNA surrounding the human ATM gene region on chromosome 11 were determined for 10 individuals, demonstrating the feasibility of this new method.

Role of nicotine dose and sensory cues in the regulation of smoke intake.

PubMed

Rose, J E; Behm, F M; Levin, E D

1993-04-01

We investigated the role of nicotine dose and sensory cues in the regulation of ad lib smoke intake. The smoking behavior of 12 adult male smokers was assessed in three conditions, presenting either high-nicotine cigarette smoke (high nicotine, high sensory), diluted cigarette smoke (low nicotine, low sensory), or an aerosol containing cigarette smoke constituents suspended in solution, which was low in nicotine, yet high in sensory impact. Subjects showed marked compensatory increases in smoking with the dilute smoke conditions, whereas they puffed and inhaled the aerosol to a similar extent as the high-nicotine cigarette. Thus, subjects regulated their smoking behavior to equate sensory intensity rather than nicotine intake. Moreover, the aerosol and high-nicotine cigarette conditions lowered craving to a greater degree than the dilute smoke condition. Other mood indices, such as arousal and negative affect, were more effectively relieved by the high-nicotine dose condition. These results highlight the importance of sensory cues in the regulation of smoke intake and modulation of craving and suggest the clinical application of techniques for providing relief of cigarette craving during smoking cessation.

Evaluation of swine fertilisation medium (SFM) efficiency in preserving spermatozoa quality during long-term storage in comparison to four commercial swine extenders.

PubMed

Fantinati, P; Zannoni, A; Bernardini, C; Forni, M; Tattini, A; Seren, E; Bacci, M L

2009-02-01

In pig production, artificial insemination is widely carried out and the use of fresh diluted semen is predominant. For this reason, there are increasing interests in developing new extenders and in establishing the optimal storage conditions for diluted spermatozoa. In the last few decades, we utilised a homemade diluent (swine fertilisation medium (SFM)) for spermatozoa manipulation and biotechnological application as the production of transgenic pigs utilising the sperm-mediated gene transfer technique. The purpose of the present study is therefore to analyse the ability of SFM, in comparison to four commercial extenders, in preserving the quality of diluted boar semen stored at 16.5°C till 15 days. We utilised some of the main predictive tests as objectively measured motility, acrosome and sperm membrane integrity, high mitochondrial membrane potential and pH. Based on our in vitro study, SFM could be declared as a good long-term extender, able to preserve spermatozoa quality as well as Androhep Enduraguard for up to 6 to 9 days and more.

Regression dilution bias: tools for correction methods and sample size calculation.

PubMed

Berglund, Lars

2012-08-01

Random errors in measurement of a risk factor will introduce downward bias of an estimated association to a disease or a disease marker. This phenomenon is called regression dilution bias. A bias correction may be made with data from a validity study or a reliability study. In this article we give a non-technical description of designs of reliability studies with emphasis on selection of individuals for a repeated measurement, assumptions of measurement error models, and correction methods for the slope in a simple linear regression model where the dependent variable is a continuous variable. Also, we describe situations where correction for regression dilution bias is not appropriate. The methods are illustrated with the association between insulin sensitivity measured with the euglycaemic insulin clamp technique and fasting insulin, where measurement of the latter variable carries noticeable random error. We provide software tools for estimation of a corrected slope in a simple linear regression model assuming data for a continuous dependent variable and a continuous risk factor from a main study and an additional measurement of the risk factor in a reliability study. Also, we supply programs for estimation of the number of individuals needed in the reliability study and for choice of its design. Our conclusion is that correction for regression dilution bias is seldom applied in epidemiological studies. This may cause important effects of risk factors with large measurement errors to be neglected.

Measurement of absolute lung volumes by imaging techniques.

PubMed

Clausen, J

1997-10-01

In this paper, the techniques available for estimating total lung capacities from standard chest radiographs in children and infants as well as adults are reviewed. These techniques include manual measurements using ellipsoid and planimetry techniques as well as computerized systems. Techniques are also available for making radiographic lung volume measurements from portable chest radiographs. There are inadequate data in the literature to support recommending one specific technique over another. Though measurements of lung volumes by radiographic, plethysmographic, gas dilution or washout techniques result in remarkably similar mean results when groups of normal subjects are tested, in patients with disease, the results of these different basic measurement techniques can differ significantly. Computed tomographic and magnetic resonance techniques can also be used to measure absolute lung volumes and offer the theoretical advantages that the results in individual subjects are less affected by variances of thoracic shape than are measurements made using conventional chest radiographs.

Quantification of ferritin bound iron in human serum using species-specific isotope dilution mass spectrometry.

PubMed

Ren, Yao; Walczyk, Thomas

2014-09-01

Ferritin is a hollow sphere protein composed of 24 subunits that can store up to 4500 iron atoms in its inner cavity. It is mainly found in the liver and spleen but also in serum at trace levels. Serum ferritin is considered as the best single indicator in assessing body iron stores except liver or bone marrow biopsy. However, it is confounded by other disease conditions. Ferritin bound iron (FBI) and ferritin saturation have been suggested as more robust biomarkers. The current techniques for FBI determination are limited by low antibody specificity, low instrument sensitivity and possible analyte losses during sample preparation. The need for a highly sensitive and reliable method is widely recognized. Here we describe a novel technique to detect serum FBI using species-specific isotope dilution mass spectrometry (SS-IDMS). [(57)Fe]-ferritin was produced by biosynthesis and in vitro labeling with the (57)Fe spike in the form of [(57)Fe]-citrate after cell lysis and heat treatment. [(57)Fe]-ferritin for sample spiking was further purified by fast liquid protein chromatography. Serum ferritin and added [(57)Fe]-ferritin were separated from other iron species by ultrafiltration followed by isotopic analysis of FBI using negative thermal ionization mass spectrometry. Repeatability of our assay is 8% with an absolute detection limit of 18 ng FBI in the sample. As compared to other speciation techniques, SS-IDMS offers maximum control over sample losses and species conversion during analysis. The described technique may therefore serve as a reference technique for clinical applications of FBI as a new biomarker for assessing body iron status.

"Techniques for Teachers" Section

ERIC Educational Resources Information Center

Manchester, P.; Ed.

1976-01-01

Presents articles on: the measurement of flouride levels in natural waters; the effect of sunlight on the rate of chlorine decomposition in a swimming pool; and curriculum development in Australian agriculture science. (MLH)

Technique for ranking potential predictor layers for use in remote sensing analysis

Treesearch

Andrew Lister; Mike Hoppus; Rachel Riemann

2004-01-01

Spatial modeling using GIS-based predictor layers often requires that extraneous predictors be culled before conducting analysis. In some cases, using extraneous predictor layers might improve model accuracy but at the expense of increasing complexity and interpretability. In other cases, using extraneous layers can dilute the relationship between predictors and target...

Fall fertilization enhanced nitrogen storage and translocation in Larix olgensis seedlings

Treesearch

Y. Zhu; R. K. Dumroese; G. L. Li; J. R. Pinto; Y. Liu

2013-01-01

Fall nutrient loading of deciduous forest nursery seedlings is of special interest because of foliage abscission and varied translocation patterns. For non-deciduous seedlings in the nursery, fall fertilization typically can reverse nutrient dilution and possibly increase nutrient reserves; however, this technique has received little attention with deciduous conifer...

Exciting transition metal doped dilute magnetic thin films: MgO:Er and ZnO:Er

NASA Astrophysics Data System (ADS)

Ćakıcı, T.; Sarıtaş, S.; Muǧlu, G. Merhan; Yıldırım, M.

2017-02-01

Erbium doped MgO and doped ZnO thin films have reasonably important properties applications in spintronic devices. These films were synthesized on glass substrates by Chemical Spray Pyrolysis (CSP) method. In the literature there has been almost no report on preparation of MgO:Er dilute magnetic thin films by means of CSP. Because doped thin films show different magnetic behaviors, depending upon the type of magnetic material ions, concentration of them, synthesis route and experimental conditions, synthesized MgO:Er and ZnO:Er films were compared to thin film properties. Optical analyses of the synthesized thin films were examined spectral absorption and transmittance measurements by UV-Vis double beam spectrophotometer technique. Structural analysis of the thin films was examined by using XRD, Raman Analysis, FE-SEM, EDX and AFM techniques. Also, magnetic properties of the MgO:Er and ZnO:Er films were investigated by vibrating sample magnetometer (VSM) which show that diamagnetic behavior of the MgO:Er thin film and ferromagnetic (FM) behavior of the ZnO:Er film were is formed.

Chemically exfoliating large sheets of phosphorene via choline chloride urea viscosity-tuning

NASA Astrophysics Data System (ADS)

Ng, A.; Sutto, T. E.; Matis, B. R.; Deng, Y.; Ye, P. D.; Stroud, R. M.; Brintlinger, T. H.; Bassim, N. D.

2017-04-01

Exfoliation of two-dimensional phosphorene from bulk black phosphorous through chemical means is demonstrated where the solvent system of choice (choline chloride urea diluted with ethanol) has the ability to successfully exfoliate large-area multi-layer phosphorene sheets and further protect the flakes from ambient degradation. The intercalant solvent molecules, aided by low-powered sonication, diffuse between the layers of the bulk black phosphorus, allowing for the exfoliation of the multi-layer phosphorene through breaking of the interlayer van der Waals bonds. Through viscosity tuning, the optimal parameters (1:1 ratio between the intercalant and the diluting solvent) at which the exfoliation takes place is determined. Our exfoliation technique is shown to produce multi-layer phosphorene flakes with surface areas greater than 3 μm2 (a factor of three larger than what has previously been reported for a similar exfoliation method) while limiting exposure to the ambient environment, thereby protecting the flakes from degradation. Characterization techniques such as optical microscopy, Raman spectroscopy, ultraviolet-visible spectroscopy, and (scanning) transmission electron microscopy are used to investigate the quality, quantity, and thickness of the exfoliated flakes.

Measurement of late-night salivary cortisol with an automated immunoassay system.

PubMed

Vogeser, Michael; Durner, Jürgen; Seliger, Ewald; Auernhammer, Christoph

2006-01-01

Measurement of late-night salivary cortisol concentrations is increasingly used as a screening test in suspected Cushing's syndrome. Cortisol concentrations are typically extremely low in late-night samples and discordant assay-specific reference ranges have been reported. Therefore, the aim of our study was to assess the analytical performance of the first automated cortisol immunoassay specified for salivary measurements and to establish late-night sampling reference-range data for this test. Salivary cortisol was measured using the Roche Cobas Cortisol assay (Roche Diagnostics). Five salivary pools in different concentration ranges were used to assess the inter-assay imprecision of this test in a two-centre evaluation protocol including two reagent lots. Linearity was tested by serial dilution. Salivary samples were obtained at 23:00 h from 100 apparently healthy volunteers using a commercially available salivary sampling device (Salivette, Sarstedt). A subset of 20 samples was used for method comparison with isotope dilution liquid chromatography-tandem mass spectrometry. Inter-assay coefficients of variation (n=20) between 11.6% and 40.4% were found for mean cortisol concentrations between 12.9 and 2.6 nmol/L, with an estimated functional sensitivity of approximately 5.0 nmol/L. The test also gave linear results in the lowest concentration range between 1.0 and 8.3 nmol/L. Mean late-night salivary cortisol of 5.0 nmol/L was found for healthy individuals; the absolute range was 1.4-16.7 nmol/L, and the 95th percentile was 8.9 nmol/L. Substantially lower concentrations were found with isotope dilution LC-MS/MS compared to immunoassay results (mean concentrations 1.8 and 4.4 nmol/L, respectively). The automated assay investigated was found to offer acceptable analytical performance in the very low concentration range required for late-night salivary cortisol, despite a very short turn-around time. Using this assay, late-night salivary cortisol concentrations below 8.9 nmol/L are typically found in healthy volunteers.

Metal speciation and potential bioavailability changes during discharge and neutralisation of acidic drainage water.

PubMed

Simpson, Stuart L; Vardanega, Christopher R; Jarolimek, Chad; Jolley, Dianne F; Angel, Brad M; Mosley, Luke M

2014-05-01

The discharge of acid drainage from the farm irrigation areas to the Murray River in South Australia represents a potential risk to water quality. The drainage waters have low pH (2.9-5.7), high acidity (up to 1190 mg L(-1) CaCO3), high dissolved organic carbon (10-40 mg L(-1)), and high dissolved Al, Co, Ni and Zn (up to 55, 1.25, 1.30 and 1.10 mg L(-1), respectively) that represent the greatest concern relative to water quality guidelines (WQGs). To provide information on bioavailability, changes in metal speciation were assessed during mixing experiments using filtration (colloidal metals) and Chelex-lability (free metal ions and weak inorganic metal complexes) methods. Following mixing of drainage and river water, much of the dissolved aluminium and iron precipitated. The concentrations of other metals generally decreased conservatively in proportion to the dilution initially, but longer mixing periods caused increased precipitation or adsorption to particulate phases. Dissolved Co, Mn and Zn were typically 95-100% present in Chelex-labile forms, whereas 40-70% of the dissolved nickel was Chelex-labile and the remaining non-labile fraction of dissolved nickel was associated with fine colloids or complexed by organic ligands that increased with time. Despite the different kinetics of precipitation, adsorption and complexation reactions, the dissolved metal concentrations were generally highly correlated for the pooled data sets, indicating that the major factors controlling the concentrations were similar for each metal (pH, dilution, and time following mixing). For dilutions of the drainage waters of less than 1% with Murray River water, none of the metals should exceed the WQGs. However, the high concentrations of metals associated with fine precipitates within the receiving waters may represent a risk to some aquatic organisms. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Comparisons among Equations Used for Retinol Isotope Dilution in the Assessment of Total Body Stores and Total Liver Reserves.

PubMed

Gannon, Bryan M; Tanumihardjo, Sherry A

2015-05-01

Vitamin A plays an essential role in animal biology and has negative effects associated with both hypo- and hypervitaminosis A. Many notable interventions are being done globally to eliminate vitamin A deficiency, including supplementation, fortification, and biofortification. At the same time, it is important to monitor vitamin A status in nations where preformed vitamin A intake is high because of consumption of animal source foods (e.g., liver, dairy, eggs), fortified foods (e.g., milk, cereals, oil, sugar, margarine), or vitamin supplements (e.g., one-a-day multivitamins) to ensure the population does not reach hypervitaminosis A. To accurately assess population status and evaluate interventions aimed at improving vitamin A status, accurate assessment methods are needed. The primary storage site of vitamin A is the liver; however, routinely obtaining liver samples from humans is impractical and unethical. Isotope dilution using deuterium- or (13)C-labeled retinol is currently the most sensitive indirect biomarker of vitamin A status across a wide range of liver reserves. The major drawback to its application is the increased technicality in sample analysis and data calculations when compared to less sensitive methodology, such as serum retinol concentrations and dose response tests. Two main equations have emerged for calculating vitamin A body pool size or liver concentrations from isotope dilution data: the "Olson equation" and the "mass balance equation." Different applications of these equations can lead to confusion and lack of consistency if the underlying principles and assumptions used are not clarified. The purpose of this focused review is to describe the evolution of the equations used in retinol stable-isotope work and the assumptions appropriate to different applications of the test. Ultimately, the 2 main equations are shown to be fundamentally the same and differ only in assumptions made for each specific research application. © 2015 American Society for Nutrition.

Boreal peatland pools C release: implication for the contemporary C exchange

NASA Astrophysics Data System (ADS)

Pelletier, L.; Strachan, I. B.; Garneau, M.; Roulet, N. T.

2013-12-01

Peatland ecosystems are considered to be net-sinks for carbon, with long-term accumulation rates ranging between 3 and 71 g C m-2 yr-1. However, the net carbon exchange rates vary significantly across the surface of these ecosystems, both in terms of magnitude and direction of the fluxes. Boreal peatlands are characterized by microforms ranging from dry hummocks, to lawns, to wet hollows and pools, which have distinct physical and chemical properties. While the hummocks and lawns absorb C due to the positive balance between gross primary production (CO2 uptake) and respiration (CO2 and CH4 release), pools represent net sources of carbon to the atmosphere. Annual pool C fluxes have been poorly documented and their contribution to the ecosystem level C budget is often ignored, even if they cover a significant portion of the peatland surface. Furthermore, the net ecosystem CO2 exchange (NEE) of these peatlands remains largely unknown. In this study, we examine the dynamics of the atmospheric exchange of CO2 and CH4 from peatland pools. Dissolved CO2 and CH4 were measured sporadically in five pools using the headspace technique and continuously with an NDIR sensor (CO2 for one pool only) over a 16-month period. Fluxes were calculated using the thin boundary layer model. We measured spring release and growing season (May to October) NEE-CO2 and CH4 fluxes in the same peatland using an eddy covariance tower to see how the presence of pools impacts the contemporary C exchange at the ecosystem level.

Establishing the interfacial nano-structure and elemental composition of homeopathic medicines based on inorganic salts: a scientific approach.

PubMed

Temgire, Mayur Kiran; Suresh, Akkihebbal Krishnamurthy; Kane, Shantaram Govind; Bellare, Jayesh Ramesh

2016-05-01

Extremely dilute systems arise in homeopathy, which uses dilution factors 10(60), 10(400) and also higher. These amounts to potencies of 30c, 200c or more, those are far beyond Avogadro's number. There is extreme skepticism among scientists about the possibility of presence of starting materials due to these high dilutions. This has led modern scientists to believe homeopathy may be at its best a placebo effect. However, our recent studies on 30c and 200c metal based homeopathic medicines clearly revealed the presence of nanoparticles of starting metals, which were found to be retained due to the manufacturing processes involved, as published earlier.(9,10) Here, we use HR-TEM and STEM techniques to study medicines arising from inorganic salts as starting materials. We show that the inorganic starting materials are present as nano-scale particles in the medicines even at 1 M potency (having a large dilution factor of 10(2000)). Thus this study has extended our physicochemical studies of metal based medicines to inorganic based medicines, and also to higher dilution. Further, we show that the particles develop a coat of silica: these particles were seen embedded in a meso-microporous silicate layer through interfacial encapsulation. Similar silicate coatings were also seen in metal based medicines. Thus, metal and inorganic salt based homeopathic medicines retain the starting material as nanoparticles encapsulated within a silicate coating. On the basis of these studies, we propose a universal microstructural hypothesis that all types of homeopathic medicines consist of silicate coated nano-structures dispersed in the solvent. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Application of Genetic Algorithm (GA) Assisted Partial Least Square (PLS) Analysis on Trilinear and Non-trilinear Fluorescence Data Sets to Quantify the Fluorophores in Multifluorophoric Mixtures: Improving Quantification Accuracy of Fluorimetric Estimations of Dilute Aqueous Mixtures.

PubMed

Kumar, Keshav

2018-03-01

Excitation-emission matrix fluorescence (EEMF) and total synchronous fluorescence spectroscopy (TSFS) are the 2 fluorescence techniques that are commonly used for the analysis of multifluorophoric mixtures. These 2 fluorescence techniques are conceptually different and provide certain advantages over each other. The manual analysis of such highly correlated large volume of EEMF and TSFS towards developing a calibration model is difficult. Partial least square (PLS) analysis can analyze the large volume of EEMF and TSFS data sets by finding important factors that maximize the correlation between the spectral and concentration information for each fluorophore. However, often the application of PLS analysis on entire data sets does not provide a robust calibration model and requires application of suitable pre-processing step. The present work evaluates the application of genetic algorithm (GA) analysis prior to PLS analysis on EEMF and TSFS data sets towards improving the precision and accuracy of the calibration model. The GA algorithm essentially combines the advantages provided by stochastic methods with those provided by deterministic approaches and can find the set of EEMF and TSFS variables that perfectly correlate well with the concentration of each of the fluorophores present in the multifluorophoric mixtures. The utility of the GA assisted PLS analysis is successfully validated using (i) EEMF data sets acquired for dilute aqueous mixture of four biomolecules and (ii) TSFS data sets acquired for dilute aqueous mixtures of four carcinogenic polycyclic aromatic hydrocarbons (PAHs) mixtures. In the present work, it is shown that by using the GA it is possible to significantly improve the accuracy and precision of the PLS calibration model developed for both EEMF and TSFS data set. Hence, GA must be considered as a useful pre-processing technique while developing an EEMF and TSFS calibration model.

An isotope-dilution UPLC-MS/MS technique for the human biomonitoring of the internal exposure to glycidol via a valine adduct at the N-terminus of hemoglobin.

PubMed

Hielscher, Jan; Monien, Bernhard H; Abraham, Klaus; Jessel, Sönke; Seidel, Albrecht; Lampen, Alfonso

2017-08-01

Fatty acid esters of glycidol (glycidyl esters) are processing contaminants generated as a byproduct of the industrial deodorization of vegetable oils and fats. Oral intake of glycidyl esters leads to the release of glycidol in the gastrointestinal tract. Glycidol is carcinogenic, genotoxic and teratogenic in rodents. It is rated as probably carcinogenic to humans (IARC group 2A). The determination of internal exposure of glycidol may support the assessment of the possible human health risks related to glycidyl ester intake. For this purpose, hemoglobin adducts of glycidol may be suitable biomarkers reflecting the cumulative exposure of up to four months. We applied a modified Edman degradation to assess the glycidol adduct at the N-terminal valine, N-(2,3-dihydroxypropyl)-valine (2,3-diHOPr-Val), of hemoglobin. The modified valine was cleaved with fluorescein-5-isothiocyanate (FITC), resulting in the formation of N-(2,3-dihydroxypropyl)-valine fluorescein thiohydantoin (DHP-Val-FTH). An isotope-dilution technique was developed for the quantification of the thiohydantoin analyte by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and DHP-Val-d 7 -FTH as reference standard. The limit of detection was 4 fmol DHP-Val-FTH per injection corresponding to 0.7pmol 2,3-diHOPr-Val/g hemoglobin. The adduct levels in blood samples of 12 non-smoking participants were in the range of 2.2-4.9pmol 2,3-diHOPr-Val/g hemoglobin. The current work presents the first isotope-dilution technique using UPLC-MS/MS for the quantification of 2,3-diHOPr-Val at the N-terminus of hemoglobin as a sensitive and convenient alternative to earlier GC-MS methods. Copyright © 2017 Elsevier B.V. All rights reserved.

A comparison of the techniques of direct pars interarticularis repairs for spondylolysis and low-grade spondylolisthesis: a meta-analysis.

PubMed

Mohammed, Nasser; Patra, Devi Prasad; Narayan, Vinayak; Savardekar, Amey R; Dossani, Rimal Hanif; Bollam, Papireddy; Bir, Shyamal; Nanda, Anil

2018-01-01

OBJECTIVE Spondylosis with or without spondylolisthesis that does not respond to conservative management has an excellent outcome with direct pars interarticularis repair. Direct repair preserves the segmental spinal motion. A number of operative techniques for direct repair are practiced; however, the procedure of choice is not clearly defined. The present study aims to clarify the advantages and disadvantages of the different operative techniques and their outcomes. METHODS A meta-analysis was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The following databases were searched: PubMed, Cochrane Library, Web of Science, and CINAHL ( Cumulative Index to Nursing and Allied Health Literature). Studies of patients with spondylolysis with or without low-grade spondylolisthesis who underwent direct repair were included. The patients were divided into 4 groups based on the operative technique used: the Buck repair group, Scott repair group, Morscher repair group, and pedicle screw-based repair group. The pooled data were analyzed using the DerSimonian and Laird random-effects model. Tests for bias and heterogeneity were performed. The I 2 statistic was calculated, and the results were analyzed. Statistical analysis was performed using StatsDirect version 2. RESULTS Forty-six studies consisting of 900 patients were included in the study. The majority of the patients were in their 2nd decade of life. The Buck group included 19 studies with 305 patients; the Scott group had 8 studies with 162 patients. The Morscher method included 5 studies with 193 patients, and the pedicle group included 14 studies with 240 patients. The overall pooled fusion, complication, and outcome rates were calculated. The pooled rates for fusion for the Buck, Scott, Morscher, and pedicle screw groups were 83.53%, 81.57%, 77.72%, and 90.21%, respectively. The pooled complication rates for the Buck, Scott, Morscher, and pedicle screw groups were 13.41%, 22.35%, 27.42%, and 12.8%, respectively, and the pooled positive outcome rates for the Buck, Scott, Morscher, and pedicle screw groups were 84.33%, 82.49%, 80.30%, and 80.1%, respectively. The pedicle group had the best fusion rate and lowest complication rate. CONCLUSIONS The pedicle screw-based direct pars repair for spondylolysis and low-grade spondylolisthesis is the best choice of procedure, with the highest fusion and lowest complication rates, followed by the Buck repair. The Morscher and Scott repairs were associated with a high rate of complication and lower rates of fusion.

Measurement of soil carbon oxidation state and oxidative ratio by 13C nuclear magnetic resonance

USGS Publications Warehouse

Hockaday, W.C.; Masiello, C.A.; Randerson, J.T.; Smernik, R.J.; Baldock, J.A.; Chadwick, O.A.; Harden, J.W.

2009-01-01

The oxidative ratio (OR) of the net ecosystem carbon balance is the ratio of net O2 and CO2 fluxes resulting from photosynthesis, respiration, decomposition, and other lateral and vertical carbon flows. The OR of the terrestrial biosphere must be well characterized to accurately estimate the terrestrial CO2 sink using atmospheric measurements of changing O2 and CO2 levels. To estimate the OR of the terrestrial biosphere, measurements are needed of changes in the OR of aboveground and belowground carbon pools associated with decadal timescale disturbances (e.g., land use change and fire). The OR of aboveground pools can be measured using conventional approaches including elemental analysis. However, measuring the OR of soil carbon pools is technically challenging, and few soil OR data are available. In this paper we test three solid-state nuclear magnetic resonance (NMR) techniques for measuring soil OR, all based on measurements of the closely related parameter, organic carbon oxidation state (Cox). Two of the three techniques make use of a molecular mixing model which converts NMR spectra into concentrations of a standard suite of biological molecules of known C ox. The third technique assigns Cox values to each peak in the NMR spectrum. We assess error associated with each technique using pure chemical compounds and plant biomass standards whose Cox and OR values can be directly measured by elemental analyses. The most accurate technique, direct polarization solid-state 13C NMR with the molecular mixing model, agrees with elemental analyses to ??0.036 Cox units (??0.009 OR units). Using this technique, we show a large natural variability in soil Cox and OR values. Soil Cox values have a mean of -0.26 and a range from -0.45 to 0.30, corresponding to OR values of 1.08 ?? 0.06 and a range from 0.96 to 1.22. We also estimate the OR of the carbon flux from a boreal forest fire. Analysis of soils from nearby intact soil profiles imply that soil carbon losses associated with the fire had an OR of 1.091 (??0.003). Fire appears to be a major factor driving the soil C pool to higher oxidation states and lower OR values. Episodic fluxes caused by disturbances like fire may have substantially different ORs from ecosystem respiration fluxes and therefore should be better quantified to reduce uncertainties associated with our understanding of the global atmospheric carbon budget. Copyright 2009 by the American Geophysical Union.

Comparison of in-air evoked potential and underwater behavioral hearing thresholds in four bottlenose dolphins (Tursiops truncatus).

PubMed

Finneran, James J; Houser, Dorian S

2006-05-01

Traditional behavioral techniques for hearing assessment in marine mammals are limited by the time and access required to train subjects. Electrophysiological methods, where passive electrodes are used to measure auditory evoked potentials (AEPs), are attractive alternatives to behavioral techniques; however, there have been few attempts to compare AEP and behavioral results for the same subject. In this study, behavioral and AEP hearing thresholds were compared in four bottlenose dolphins. AEP thresholds were measured in-air using a piezoelectric sound projector embedded in a suction cup to deliver amplitude modulated tones to the dolphin through the lower jaw. Evoked potentials were recorded noninvasively using surface electrodes. Adaptive procedures allowed AEP hearing thresholds to be estimated from 10 to 150 kHz in a single ear in about 45 min. Behavioral thresholds were measured in a quiet pool and in San Diego Bay. AEP and behavioral threshold estimates agreed closely as to the upper cutoff frequency beyond which thresholds increased sharply. AEP thresholds were strongly correlated with pool behavioral thresholds across the range of hearing; differences between AEP and pool behavioral thresholds increased with threshold magnitude and ranged from 0 to + 18 dB.

NMF-Based Image Quality Assessment Using Extreme Learning Machine.

PubMed

Wang, Shuigen; Deng, Chenwei; Lin, Weisi; Huang, Guang-Bin; Zhao, Baojun

2017-01-01

Numerous state-of-the-art perceptual image quality assessment (IQA) algorithms share a common two-stage process: distortion description followed by distortion effects pooling. As for the first stage, the distortion descriptors or measurements are expected to be effective representatives of human visual variations, while the second stage should well express the relationship among quality descriptors and the perceptual visual quality. However, most of the existing quality descriptors (e.g., luminance, contrast, and gradient) do not seem to be consistent with human perception, and the effects pooling is often done in ad-hoc ways. In this paper, we propose a novel full-reference IQA metric. It applies non-negative matrix factorization (NMF) to measure image degradations by making use of the parts-based representation of NMF. On the other hand, a new machine learning technique [extreme learning machine (ELM)] is employed to address the limitations of the existing pooling techniques. Compared with neural networks and support vector regression, ELM can achieve higher learning accuracy with faster learning speed. Extensive experimental results demonstrate that the proposed metric has better performance and lower computational complexity in comparison with the relevant state-of-the-art approaches.

Effect of Molten Pool Size on Microstructure and Tensile Properties of Wire Arc Additive Manufacturing of Ti-6Al-4V Alloy.

PubMed

Wu, Qianru; Lu, Jiping; Liu, Changmeng; Fan, Hongli; Shi, Xuezhi; Fu, Jie; Ma, Shuyuan

2017-07-04

Wire arc additive manufacturing (WAAM) technique is a cost-competitive and efficient technology to produce large structure components in industry domains. Mechanical properties are mainly dominated by the microstructure of the components, which is deeply affected by the molten pool size. In this work, to investigate the effect of the molten pool size on microstructure and mechanical properties of the components, a series of Ti-6Al-4V alloy blocks with different width of molten pool (WMP) ranging from 7 mm to 22 mm were deposited by adjusting the wire feed speed (WFS) from 100 cm/min to 500 cm/min. It is interesting to find that the macrostructure changes from columnar grains to equiaxial grains, and then returns to large columnar grains with the increase of WMP, which is mainly caused by the different cooling rates and thermal gradients. Nonetheless, the tensile properties of the components have a tendency to decline with the increase of WMP.

Effect of Molten Pool Size on Microstructure and Tensile Properties of Wire Arc Additive Manufacturing of Ti-6Al-4V Alloy

PubMed Central

Wu, Qianru; Lu, Jiping; Liu, Changmeng; Fan, Hongli; Shi, Xuezhi; Fu, Jie; Ma, Shuyuan

2017-01-01

Wire arc additive manufacturing (WAAM) technique is a cost-competitive and efficient technology to produce large structure components in industry domains. Mechanical properties are mainly dominated by the microstructure of the components, which is deeply affected by the molten pool size. In this work, to investigate the effect of the molten pool size on microstructure and mechanical properties of the components, a series of Ti-6Al-4V alloy blocks with different width of molten pool (WMP) ranging from 7 mm to 22 mm were deposited by adjusting the wire feed speed (WFS) from 100 cm/min to 500 cm/min. It is interesting to find that the macrostructure changes from columnar grains to equiaxial grains, and then returns to large columnar grains with the increase of WMP, which is mainly caused by the different cooling rates and thermal gradients. Nonetheless, the tensile properties of the components have a tendency to decline with the increase of WMP. PMID:28773107

Effect of Laser Power and Scan Speed on Melt Pool Characteristics of Commercially Pure Titanium (CP-Ti)

NASA Astrophysics Data System (ADS)

Kusuma, Chandrakanth; Ahmed, Sazzad H.; Mian, Ahsan; Srinivasan, Raghavan

2017-07-01

Selective laser melting (SLM) is an additive manufacturing technique that creates complex parts by selectively melting metal powder layer-by-layer using a laser. In SLM, the process parameters decide the quality of the fabricated component. In this study, single beads of commercially pure titanium (CP-Ti) were melted on a substrate of the same material using an in-house built SLM machine. Multiple combinations of laser power and scan speed were used for single bead fabrication, while the laser beam diameter and powder layer thickness were kept constant. This experimental study investigated the influence of laser power, scan speed, and laser energy density on the melt pool formation, surface morphology, geometry (width and height), and hardness of solidified beads. In addition, the observed unfavorable effect such as inconsistency in melt pool width formation is discussed. The results show that the quality, geometry, and hardness of solidified melt pool are significantly affected by laser power, scanning speed, and laser energy density.

Stated and revealed inequality aversion in three subject pools

PubMed Central

Beranek, Benjamin; Cubitt, Robin; Gächter, Simon

2016-01-01

This paper reports data from three subject pools (n=717 subjects) using techniques based on those of Loewenstein, et al. (1989) and Blanco, et al. (2011) to obtain parameters, respectively, of stated and revealed inequality aversion. We provide a replication opportunity for those papers, with two innovations: (i) a design which allows stated and revealed preferences to be compared at the individual level; (ii) assessment of robustness of findings across subjects from a UK university, a Turkish university and Amazon Mechanical Turk. Our findings on stated aversion to inequality are qualitatively similar to those of Loewenstein, et al. in each of our subject pools, whereas there are notable differences between some of our findings on revealed preference and those of Blanco, et al. We find that revealed advantageous inequality aversion is often stronger than revealed dis-advantageous inequality aversion. In most subject pools, we find some (weak) correlation between corresponding parameters of stated and revealed inequality aversion. PMID:27069847

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

Marchisio, Mario Andrea, E-mail: marchisio@hit.edu.cn

Published in 2008, Parts & Pools represents one of the first attempts to conceptualize the modular design of bacterial synthetic gene circuits with Standard Biological Parts (DNA segments) and Pools of molecules referred to as common signal carriers (e.g., RNA polymerases and ribosomes). The original framework for modeling bacterial components and designing prokaryotic circuits evolved over the last years and brought, first, to the development of an algorithm for the automatic design of Boolean gene circuits. This is a remarkable achievement since gene digital circuits have a broad range of applications that goes from biosensors for health and environment caremore » to computational devices. More recently, Parts & Pools was enabled to give a proper formal description of eukaryotic biological circuit components. This was possible by employing a rule-based modeling approach, a technique that permits a faithful calculation of all the species and reactions involved in complex systems such as eukaryotic cells and compartments. In this way, Parts & Pools is currently suitable for the visual and modular design of synthetic gene circuits in yeast and mammalian cells too.« less

Comparison of a single indicator and gravimetric technique for estimation of extravascular lung water in endotoxemic pigs.

PubMed

Rossi, Patrik; Wanecek, Michael; Rudehill, Anders; Konrad, David; Weitzberg, Eddie; Oldner, Anders

2006-05-01

To compare the single thermal indicator dilution (STID) technique for measurement of extravascular lung water (EVLW(STID)) with gravimetrically determined EVLW (EVLW(GRAV)) in anesthetized pigs under sham and endotoxemic conditions. Open experimental comparative animal study. University animal research laboratory. Fifteen anesthetized landrace pigs. Endotoxin infusion during 5 hrs in five pigs. Six animals were only anesthetized and rested for 5 hrs. In four additional animals, the impact on EVLW(STID) measurements by changes in pulmonary perfusion, ventilation, and the combination of the two was studied. The alterations in ventilation and perfusion were induced by caval balloon inflation, inflation of the pulmonary artery catheter balloon, and bronchial plugging respectively. The STID technique, with default settings of the intrathoracic blood volume (ITBV) to global end-diastolic volume (GEDV) (i.e., the extrapulmonary intravascular volume between the point of injection of the indicator, and the point of detection) relationship (ITBV = 1.25GEDV), systematically overestimated the EVLW index compared with the gravimetrical method (mean bias of 5.4 mL/kg). By adapting the ITBV to GEDV relationship to the current model (ITBV = 1.52GEDV + 49.7), the accuracy of the STID technique improved. Moreover, the measurement of EVLW(STID) proved to be reduced by manipulation of pulmonary perfusion and ventilation. However, the STID technique could detect an increase in EVLW during endotoxemia independent of the ITBV/GEDV relationship used. Despite technological improvement, the dilution techniques for the measurement of EVLW might still be influenced by changes in perfusion and ventilation. The STID technique, in addition, might demand adjustment of the ITBV/GEDV relationship to the particular condition and species subjected to measurement. The STID technique may, however, be a useful tool for monitoring changes of EVLW over time, but further studies are warranted to confirm this.

On the thermal stability of physical vapor deposited oxide-hardened nanocrystalline gold thin films

DOE PAGES

Argibay, Nicolas; Mogonye, J. E.; Michael, Joseph R.; ...

2015-04-08

We describe a correlation between electrical resistivity and grain size for PVD synthesized polycrystalline oxide-hardened metal-matrix thin films in oxide-dilute (<5 vol. % oxide phase) compositions. The correlation is based on the Mayadas-Shatzkes (M-S) electron scattering model, predictive of grain size evolution as a function of composition in the oxide-dilute regime for 2 μm thick Au-ZnO films. We describe a technique to investigate grain boundary (GB) mobility and the thermal stability of GBs based on in situelectrical resistivity measurements during annealing experiments, interpreted using a combination of the M-S model and the Michels et al. model describing solute drag stabilizedmore » grain growth kinetics. Using this technique, activation energy and pre-exponential Arrhenius parameter values of E a = 21.6 kJ/mol and A o = 2.3 × 10 -17 m 2/s for Au-1 vol. % ZnO and E a =12.7 kJ/mol and A o = 3.1 × 10 -18 m 2/s for Au-2 vol.% ZnO were determined. In the oxide-dilute regime, the grain size reduction of the Au matrix yielded a maximum hardness of 2.6 GPa for 5 vol. % ZnO. A combined model including percolation behavior and grain refinement is presented that accurately describes the composition dependent change in electrical resistivity throughout the entire composition range for Au-ZnO thin films. As a result, the proposed correlations are supported by microstructural characterization using transmission electron microscopy and electron diffraction mapping for grain size determination.« less

Modulation of mitochondrial function by endogenous Zn2+ pools

NASA Astrophysics Data System (ADS)

Sensi, Stefano L.; Ton-That, Dien; Sullivan, Patrick G.; Jonas, Elizabeth A.; Gee, Kyle R.; Kaczmarek, Leonard K.; Weiss, John H.

2003-05-01

Recent evidence suggests that intracellular Zn2+ accumulation contributes to the neuronal injury that occurs in epilepsy or ischemia in certain brain regions, including hippocampus, amygdala, and cortex. Although most attention has been given to the vesicular Zn2+ that is released into the synaptic space and may gain entry to postsynaptic neurons, recent studies have highlighted pools of intracellular Zn2+ that are mobilized in response to stimulation. One such Zn2+ pool is likely bound to cytosolic proteins, like metallothioneins. Applying imaging techniques to cultured cortical neurons, this study provides novel evidence for the presence of a mitochondrial pool distinct from the cytosolic protein or ligand-bound pool. These pools can be pharmacologically mobilized largely independently of each other, with Zn2+ release from one resulting in apparent net Zn2+ transfer to the other. Further studies found evidence for complex and potent effects of Zn2+ on isolated brain mitochondria. Submicromolar levels, comparable to those that might occur on strong mobilization of intracellular compartments, induced membrane depolarization (loss of m), increases in currents across the mitochondrial inner membrane as detected by direct patch clamp recording of mitoplasts, increased O2 consumption and decreased reactive oxygen species (ROS) generation, whereas higher levels decreased O2 consumption and increased ROS generation. Finally, strong mobilization of protein-bound Zn2+ appeared to induce partial loss of Δψm, suggesting that movement of Zn2+ between cytosolic and mitochondrial pools might be of functional significance in intact neurons.

Assessing the stability of soil organic matter by fractionation and 13C isotope techniques

NASA Astrophysics Data System (ADS)

Larionova, A. A.; Zolotareva, B. N.; Kvitkina, A. K.; Evdokimov, I. V.; Bykhovets, S. S.; Stulin, A. F.; Kuzyakov, Ya. V.; Kudeyarov, V. N.

2015-02-01

Carbon pools of different stabilities have been separated from the soil organic matter of agrochernozem and agrogray soil samples. The work has been based on the studies of the natural abundance of the carbon isotope composition by C3-C4 transition using the biokinetic, size-density, and chemical fractionation (6 M HCl hydrolysis) methods. The most stable pools with the minimum content of new carbon have been identified by particle-size and chemical fractionation. The content of carbon in the fine fractions has been found to be close to that in the nonhydrolyzable residue. This pool makes up 65 and 48% of Corg in the agrochernozems and agrogray soils, respectively. The combination of the biokinetic approach with particle-size fractionation or 6 M HCl hydrolysis has allowed assessing the size of the medium-stable organic carbon pool with a turnover time of several years to several decades. The organic matter pool with this turnover rate is usually identified from the variation in the 13C abundance by C3-C4 transition. In the agrochernozems and agrogray soils, the medium-stable carbon pool makes up 35 and 46% of Corg, respectively. The isotope indication may be replaced by a nonisotope method to significantly expand the study of the inert and mediumstable organic matter pools in the geographical aspect, but this requires a comparative analysis of particle-size and chemical fractionation data for all Russian soils.

Distribution of spermatozoa and embryos in the female reproductive tract after unilateral deep intra uterine insemination in the pig.

PubMed

Tummaruk, P; Sumransap, P; Techakumphu, M; Kunavongkrit, A

2007-12-01

The present study was performed to investigate the number of either the spermatozoa or the embryos in the reproductive tracts of sows after unilateral, deep, intra uterine insemination (DIUI). Two experiments were conducted, 10 sows were used in experiment I and eight sows were used in experiment II. Transrectal ultrasonography was used to examine the time when ovulation took place in relation to oestrus behaviour. The sows were inseminated with a single dose of diluted fresh semen 6-8 h prior to expected ovulation, during the second oestrus after weaning. In experimental I, five sows were inseminated by a conventional artificial insemination (AI) technique using 100 ml of diluted fresh semen, containing 3000 x 10(6) motile spermatozoa and five sows were inseminated by the DIUI technique with 5 ml of diluted fresh semen, containing 150 x 10(6) motile spermatozoa. The sows were anesthetized and ovario-hysterectomized approximately 24 h after insemination. The oviducts and the uterine horns on each side of the reproductive tracts were divided into seven segments, namely ampulla, cranial isthmus, caudal isthmus, utero-tubal junction (UTJ), cranial uterine horn, middle uterine horn and caudal uterine horn. Each segment of the reproductive tracts was flushed with Beltsville thawing solution (BTS) through the lumen. The total number of spermatozoa in the flushing from each segment were determined. In experimental II, eight sows were inseminated by the DIUI technique using 5.0 ml diluted fresh semen containing 150 x 10(6) motile spermatozoa. The sows were anesthetized 61.1 +/- 12 h after insemination (48-72 h) and the embryos were flushed from the oviduct through the proximal part of the uterine horn. It was revealed that, in experimental I, the spermatozoa were recovered from both sides of the reproductive tract in the AI-group, and from unilateral side of the reproductive tract in the DIUI-group (three sows from the left and two sows from the right sides). The number of spermatozoa recovered from the reproductive tracts was higher in the AI- than the DIUI-group (p < 0.001). In experiment II, fertilization occurred in five of eight sows (62.5%) after DIUI. The number of ova that ovulated were 16.4 +/- 2.6 per sow and the embryos numbering 11.4 +/- 2.3 per sow were recovered from both sides of the reproductive tract. In conclusion, the spermatozoa given by DIUI could be recovered from only one side of the reproductive tract of sows at approximately 24 h after DIUI via the flushing technique. However, embryos were found in both sides of the oviducts and the proximal part of the uterine horns 48-72 h after insemination, indicating that the fertilization occurred in both sides of the oviducts.

Investigation of the Biogenic Origin of Cave Pool Precipitates in the Guadalupe Mountains, NM Using Extracted Phospholipids and Other Biomarkers

NASA Astrophysics Data System (ADS)

Kooser, A. S.; Crossey, L.; Northup, D.; Spilde, M.; Melim, L.

2008-12-01

Biomarker analysis is an important tool for understanding biogenic carbonates. Past and present bacterial communities utilize chemical species present in the cave environments for metabolic processes and may directly or indirectly contribute to carbonate production. Paleo-communities of bacteria are preserved in speleothems (cave formations) called pool fingers. These speleothems range from 1-4 cm in diameter, 5- 50cm in length and contain alternating layers of micritic calcite and dog tooth spar. The outer portion of the finger can have a moonmilk coating. Pool fingers contain fossilized microbes that can be seen using scanning electron microscopy on etch samples. The lithified communities also leave behind fingerprints in the form of biomarkers. The biomarkers are extracted from pool fingers using a series of solvent washes; the products of each wash are analyzed using gas chromatography followed by gas chromatography/mass spectroscopy. Six samples including pool spar (abiotic speleothem) were examined using this technique. The moonmilk portion of the large pool finger from Cottonwood Cave contained several short-chained fatty acids (C16-C22), which are of microbial origin. In the polar fraction unknown hopanes were detected. The presence of a hopanes with short-chained fatty acids confirms the presence of bacterial biomarkers in the moonmilk portion of the pool finger. The pool spar sample (assumed to be abiotic) produced a different mass spectral pattern for the acid fraction and polar fraction. The acid fraction contains short-chain fatty acids (C16-22), but there are no hopanes present in the other fractions. The polar fraction for the polar spar is dominated by plant biomarkers producing the 'rainbow' spectra of C22 and higher chains. The pool finger, which is thought to be partially biogenic, contains both fossilized bacteria and bacteria biomarkers while the pool spar contains general biomarkers and plant biomarkers. The plant biomarkers found in the pool spar may have originated in the roots of the desert plants over the cave system. The presence of microbial biomarkers in the micritic layer of the pool finger and their absence in the pool spar provide support for the biogenicity of the micritic layers of cave pool fingers.

Observed Structure and Characteristics of Cold Pools over Tropical Oceans using Vector Wind Retrievals and WRF simulations

NASA Astrophysics Data System (ADS)

Garg, P.; Nesbitt, S. W.; Lang, T. J.; Chronis, T.; Thayer, J. D.; Hence, D. A.

2017-12-01

Cold pools generated in the wake of convective activity can enhance the surface sensible heat flux, latent heat flux, and also changes in evaporation out of, and fresh water flux into, the ocean. Recent studies have shown that over the open ocean, cold pool outflow boundaries and their intersections can organize and initiate a spectrum of deep convective clouds, which is a key driver of shallow and deep convection over conditionally-unstable tropical oceans. The primary goal of this study is to understand the structure and characteristics of cold pools over the tropical oceans using observations. With the idea that cold pools will have strong wind gradients at their boundaries, we use ASCAT vector wind retrievals. We identify regions of steep gradients in wind vectors as gradient features (GFs), akin to cold pools. Corresponding to these GFs, sensible and latent heat fluxes were calculated using the observed winds and background temperatures from MERRA-2 reanalysis. To evaluate the proposed technique, cold pools were observed using S-PolKa radar from the DYNAMO/AMIE field campaign in the Indian Ocean for the period of 1 October 2011 to 31 March 2012 and were compared with ASCAT GFs. To relate the thermodynamic and kinematic characteristics of observed and simulated cold pools, simulations were carried out on WRF on a 3-km domain explicitly. The areas of cold pools were identified in the models using virtual temperature (Tv), which is a direct measure of air density, while GFs were identified using model simulated winds. Quantitative measures indicate that GFs are highly correspondent with model-simulated cold pools. In global measurements of cold pools from 2007-2015, it is possible to examine the characteristics of GFs across all tropical ocean basins, and relate them to meteorological conditions, as well as the characteristics of the parent precipitation systems. Our results indicate that while there is a general relationship between the amount of precipitation and the number of cold pools, the largest cold pools exist over the Eastern Pacific basin, where the most stratiform rain is produced from oceanic MCSs. It is anticipated that improved understanding of cold pools, which are a primary triggering mechanism of oceanic shallow and deep convection, will improve prediction of this important component of the climate system.

Composition of ammonia-oxidizing archaea and their contribution to nitrification in a high-temperature hot spring

NASA Astrophysics Data System (ADS)

Chen, S.; Peng, X.-T.; Xu, H.-C.; Ta, K.-W.

2015-10-01

The oxidation of ammonia by microbes and associated organisms has been shown to occur in diverse natural environments. However, the contribution of ammonia-oxidizing archaea to nitrification in high-temperature environments remains unclear. Here, we studied in situ ammonia oxidation rates and the abundance of ammonia-oxidizing archaea (AOA) in surface and bottom sediments at 77 °C in the Gongxiaoshe hot spring, Tengchong, Yunnan, China. The in situ ammonia oxidation rates measured by the 15N-NO3- pool dilution technique in the surface sinter and bottom sediments were 4.8 and 5.3 nmol N g-1 h-1, respectively. Relative abundances of Crenarchaea in both samples were determined by fluorescence in situ hybridization (FISH). Phylogenetic analysis of 16S rRNA genes showed high sequence similarity to thermophilic "Candidatus Nitrosocaldus yellowstonii", which represented the most abundant operation taxonomic units (OTU) in both sediments. Furthermore, bacterial amoA was not detected in this study. Quantitative PCR (qPCR) indicated that AOA and 16S rRNA genes were present in the range of 2.75 to 9.80 × 105 and 0.128 to 1.96 × 108 gene copies g-1 sediment. The cell-specific nitrification rates were estimated to be in the range of 0.41 to 0.79 fmol N archaeal cell-1 h-1, which is consistent with earlier estimates in estuary environments. This study demonstrated that AOA were widely involved in nitrification in this hot spring. It further indicated the importance of archaea rather than bacteria in driving the nitrogen cycle in terrestrial geothermal environments.

Nitrification of archaeal ammonia oxidizers in a high- temperature hot spring

NASA Astrophysics Data System (ADS)

Chen, Shun; Peng, Xiaotong; Xu, Hengchao; Ta, Kaiwen

2016-04-01

The oxidation of ammonia by microbes has been shown to occur in diverse natural environments. However, the link of in situ nitrification activity to taxonomic identities of ammonia oxidizers in high-temperature environments remains poorly understood. Here, we studied in situ ammonia oxidation rates and the diversity of ammonia-oxidizing Archaea (AOA) in surface and bottom sediments at 77 °C in the Gongxiaoshe hot spring, Tengchong, Yunnan, China. The in situ ammonia oxidation rates measured by the 15N-NO3- pool dilution technique in the surface and bottom sediments were 4.80 and 5.30 nmol N g-1 h-1, respectively. Real-time quantitative polymerase chain reaction (qPCR) indicated that the archaeal 16S rRNA genes and amoA genes were present in the range of 0.128 to 1.96 × 108 and 2.75 to 9.80 × 105 gene copies g-1 sediment, respectively, while bacterial amoA was not detected. Phylogenetic analysis of 16S rRNA genes showed high sequence similarity to thermophilic Candidatus Nitrosocaldus yellowstonii, which represented the most abundant operational taxonomic units (OTU) in both surface and bottom sediments. The archaeal predominance was further supported by fluorescence in situ hybridization (FISH) visualization. The cell-specific rate of ammonia oxidation was estimated to range from 0.410 to 0.790 fmol N archaeal cell-1 h-1, higher than those in the two US Great Basin hot springs. These results suggest the importance of archaeal rather than bacterial ammonia oxidation in driving the nitrogen cycle in terrestrial geothermal environments.

Flux Analysis of Free Amino Sugars and Amino Acids in Soils by Isotope Tracing with a Novel Liquid Chromatography/High Resolution Mass Spectrometry Platform.

PubMed

Hu, Yuntao; Zheng, Qing; Wanek, Wolfgang

2017-09-05

Soil fluxomics analysis can provide pivotal information for understanding soil biochemical pathways and their regulation, but direct measurement methods are rare. Here, we describe an approach to measure soil extracellular metabolite (amino sugar and amino acid) concentrations and fluxes based on a 15 N isotope pool dilution technique via liquid chromatography and high-resolution mass spectrometry. We produced commercially unavailable 15 N and 13 C labeled amino sugars and amino acids by hydrolyzing peptidoglycan isolated from isotopically labeled bacterial biomass and used them as tracers ( 15 N) and internal standards ( 13 C). High-resolution (Orbitrap Exactive) MS with a resolution of 50 000 allowed us to separate different stable isotope labeled analogues across a large range of metabolites. The utilization of 13 C internal standards greatly improved the accuracy and reliability of absolute quantification. We successfully applied this method to two types of soils and quantified the extracellular gross fluxes of 2 amino sugars, 18 amino acids, and 4 amino acid enantiomers. Compared to the influx and efflux rates of most amino acids, similar ones were found for glucosamine, indicating that this amino sugar is released through peptidoglycan and chitin decomposition and serves as an important nitrogen source for soil microorganisms. d-Alanine and d-glutamic acid derived from peptidoglycan decomposition exhibited similar turnover rates as their l-enantiomers. This novel approach offers new strategies to advance our understanding of the production and transformation pathways of soil organic N metabolites, including the unknown contributions of peptidoglycan and chitin decomposition to soil organic N cycling.

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

Hunter, Scott R.; Efird, Marty

The purpose of the technology maturation project was to develop an enhanced application technique for applying diatomaceous earth with pinned polysiloxane oil to PVC pipes and materials. The oil infiltration technique is applied as a spray of diluted oil in a solvent onto the superhydrophobic diatomaceous earth substrate. This makes the surface take on the following characteristics: wet-cleanable; anti-biofouling; waterproof; and anti-corrosion. The project involved obtaining input and supplies from VeloxFlow and the development of successful techniques that would quickly result in a commercial license agreement with VeloxFlow and other companies that use PVC materials in a variety of othermore » fields of use.« less

Individual cell lag time distributions of Cronobacter (Enterobacter sakazakii) and impact of pooling samples on its detection in powdered infant formula.

PubMed

Miled, Rabeb Bennour; Guillier, Laurent; Neves, Sandra; Augustin, Jean-Christophe; Colin, Pierre; Besse, Nathalie Gnanou

2011-06-01

Cells of six strains of Cronobacter were subjected to dry stress and stored for 2.5 months at ambient temperature. The individual cell lag time distributions of recovered cells were characterized at 25 °C and 37 °C in non-selective broth. The individual cell lag times were deduced from the times taken by cultures from individual cells to reach an optical density threshold. In parallel, growth curves for each strain at high contamination levels were determined in the same growth conditions. In general, the extreme value type II distribution with a shape parameter fixed to 5 (EVIIb) was the most effective at describing the 12 observed distributions of individual cell lag times. Recently, a model for characterizing individual cell lag time distribution from population growth parameters was developed for other food-borne pathogenic bacteria such as Listeria monocytogenes. We confirmed this model's applicability to Cronobacter by comparing the mean and the standard deviation of individual cell lag times to populational lag times observed with high initial concentration experiments. We also validated the model in realistic conditions by studying growth in powdered infant formula decimally diluted in Buffered Peptone Water, which represents the first enrichment step of the standard detection method for Cronobacter. Individual lag times and the pooling of samples significantly affect detection performances. Copyright © 2010 Elsevier Ltd. All rights reserved.

Selective parathyroid venous sampling in primary hyperparathyroidism: A systematic review and meta-analysis.

PubMed

Ibraheem, Kareem; Toraih, Eman A; Haddad, Antoine B; Farag, Mahmoud; Randolph, Gregory W; Kandil, Emad

2018-05-14

Minimally invasive parathyroidectomy requires accurate preoperative localization techniques. There is considerable controversy about the effectiveness of selective parathyroid venous sampling (sPVS) in primary hyperparathyroidism (PHPT) patients. The aim of this meta-analysis is to examine the diagnostic accuracy of sPVS as a preoperative localization modality in PHPT. Studies evaluating the diagnostic accuracy of sPVS for PHPT were electronically searched in the PubMed, EMBASE, Web of Science, and Cochrane Controlled Trials Register databases. Two independent authors reviewed the studies, and revised quality assessment of diagnostic accuracy study tool was used for the quality assessment. Study heterogeneity and pooled estimates were calculated. Two hundred and two unique studies were identified. Of those, 12 studies were included in the meta-analysis. Pooled sensitivity, specificity, and positive likelihood ratio (PLR) of sPVS were 74%, 41%, and 1.55, respectively. The area-under-the-receiver operating characteristic curve was 0.684, indicating an average discriminatory ability of sPVS. On comparison between sPVS and noninvasive imaging modalities, sensitivity, PLR, and positive posttest probability were significantly higher in sPVS compared to noninvasive imaging modalities. Interestingly, super-selective venous sampling had the highest sensitivity, accuracy, and positive posttest probability compared to other parathyroid venous sampling techniques. This is the first meta-analysis to examine the accuracy of sPVS in PHPT. sPVS had higher pooled sensitivity when compared to noninvasive modalities in revision parathyroid surgery. However, the invasiveness of this technique does not favor its routine use for preoperative localization. Super-selective venous sampling was the most accurate among all other parathyroid venous sampling techniques. Laryngoscope, 2018. © 2018 The American Laryngological, Rhinological and Otological Society, Inc.

In Situ Local Fracture Flow Measurement by the Double Packer Dilution Test

NASA Astrophysics Data System (ADS)

Englert, A.; Le Borgne, T.; Bour, O.; Klepikova, M.; Lavenant, N.

2011-12-01

For prediction of flow and transport in fractured media, prior estimation of the fracture network is essential, but challenging. Recent developments in hydraulic tomography have shown promising results for understanding connectivities between boreholes. However, as the hydraulic tomographic survey is typically based on the propagation of head only, it becomes a strongly non unique problem. To reduce the non uniqueness of tomographic surveys point conditioning has been found beneficial. Just as well, measurement of local flow in a fracture can serve as point conditioning for hydraulic and tracer tomographic surveys. Nevertheless, only few measurements of local fracture flow have been performed since this type of measurements implies several important technical issues. Dilution test in a packed off interval is a possible method for measuring fracture flow (e.g. Drost et al. 1968, Novakowski et al., 2005). However, a key issue for estimating flow with dilution tests is to ensure a full mixing of the tracer in the packed interval. This is typically done by including a mixing system within the packer. The design of such system can be challenging for deep wells and small diameters. Here, we propose a method where mixing is ensured by a recirculation loop including a surface tank. This method is adapted from the design proposed by Brouyere et al. (2008), who measured dilution in open wells. Dilution is quantified by measuring the concentration in the surface barrel as function of time. Together with the measurement of the circulating flow and the water filled volume in the surface barrel, the measured tracer dilution allows for calculation of the fracture flow. Since the method can be applied using a classical double packer system, it may provide a broader application of local flow measurements in heterogeneous media. We tested the approach on the Ploemeur fractured crystalline rock site. A one meter interval at depth 80 m with a single flowing fracture was isolated with a double packer dilution system. We performed a pumping test in the adjacent well. Different flow rates were estimated from the dilution curves for the different pumping rates in the adjacent well, showing a linear response. The obtained fracture flow rates provide important information on the flow geometry and connectivity between the two wells. Future joint interpretation of flow measurements, hydraulic head and tracer test data is expected to provide detailed insights in the flow and transport processes at the Ploemeur site. Drost, W., Klotz, D., Koch, A., Moser, H., Neumaier, F., Rauert, W.: Point dilution methods of investigating ground water flow by means of radioisotopes, Water. Resour. Res., 4(1), 1968. Novakowski, K., Bickerton, G., Lapcevic, P., Voralek, J., Ross, N.: Measurements of groundwater velocity in discrete rock fractures: Jour. Cont. Hydr., 82(1-2), 2006. Brouyere, S., Batlle-Aguilar, J., Goderniaux, P., Dassargues, A.: A new tracer technique for monitoring groundwater fluxes: The Finite Volume Point Dilution Method, Jour. Cont. Hydr., 95(3-4), 121-140, 2008.

Dilution and Mixing in transient velocity fields: a first-order analysis

NASA Astrophysics Data System (ADS)

Di Dato, Mariaines; de Barros, Felipe, P. J.; Fiori, Aldo; Bellin, Alberto

2017-04-01

An appealing remediation technique is in situ oxidation, which effectiveness is hampered by difficulties in obtaining good mixing of the injected oxidant with the contaminant, particularly when the contaminant plume is contained and therefore its deformation is physically constrained. Under such conditions (i.e. containment), mixing may be augmented by inducing temporal fluctuations of the velocity field. The temporal variability of the flow field may increase the deformation of the plume such that diffusive mass flux becomes more effective. A transient periodic velocity field can be obtained by an engineered sequence of injections and extractions from wells, which may serve also as a hydraulic barrier to confine the plume. Assessing the effectiveness of periodic flows to maximize solute mixing is a difficult task given the need to use a 3D setup and the large number of possible flow configurations that should be analyzed in order to identify the optimal one. This is the typical situation in which analytical solutions, though approximated, may assist modelers in screening possible alternative flow configurations such that solute dilution is maximized. To quantify dilution (i.e. a precondition that enables reactive mixing) we utilize the concept of the dilution index [1]. In this presentation, the periodic flow takes place in an aquifer with spatially variable hydraulic conductivity field which is modeled as a Stationary Spatial Random Function. We developed a novel first-order analytical solution of the dilution index under the hypothesis that the flow can be approximated as a sequence of steady state configurations with the mean velocity changing with time in intensity and direction. This is equivalent to assume that the characteristic time of the transient behavior is small compared to the period characterizing the change in time of the mean velocity. A few closed paths have been analyzed quantifying their effectiveness in enhancing dilution and thereby mixing between the resident contaminant and an oxidant. In particular, we considered three different flow configurations: (1) a "circular" pattern, in which the vector of the mean velocity rotates at a constant celerity; (2) a "shake" pattern, in which the velocity has a constant magnitude and changes direction alternatively leading to a "back and forth" type of movement and finally (3) a more general "shake and rotate" pattern, which combines the previous two configurations. The new analytical solution shows that dilution is affected by the configuration of the periodic mean flow. Results show that the dilution index increases when the rotation-shake configuration is adopted. In addition, the dilution index is augmented with the oscillation amplitude of the shake component. This analysis is useful to identify optimal flow configurations that may be approximately reproduced in the field and which efficiency may be checked more accurately by numerical simulations, thereby alleviating the computational burden by efficiently screening among alternative configurations. References [1] Kitanidis, P. K. (1994), The concept of the Dilution Index, Water Resour. Res., 30(7), 2011-2026, doi:10.1029/94WR00762.

Pool-site fuel inspection and examination techniques applied by the Kraftwerk Union Aktiengesellschaft Fuel Service. [PWR; BWR

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

Knaab, H.; Knecht, K.

The need for pool-site inspection and examination of fuel assemblies was recognized by Kraftwerk Union Aktiengesellschaft with the commissioning of the first nuclear power stations. A wet sipping method has demonstrated high reliability in detection of leaking fuel assemblies. The visual inspection system is a versatile tool. It can be supplemented by attaching devices for oxide thickness measurement or surface replication. Repair of leaking pressurized water reactor fuel assemblies has improved fuel utilization. Applied methods and typical results are described.

Gas Fride Heat Pumps : The Present and Future

NASA Astrophysics Data System (ADS)

Kurosawa, Shigekichi; Ogura, Masao

In japan techniques for saving energy is an important goal since energy resources such as oil and nuclear power are limited. Recently gas fired absorption heat pumps and gas engine driven heat pumps have been installed in facilifies such as hotels, swimming pools and offices.
In this article recent techniques, applications and future aspects for gas fired heat pumps are explained.

Development and testing of highway storm-sewer flow measurement and recording system

USGS Publications Warehouse

Kilpatrick, F.A.; Kaehrle, W.R.; Hardee, Jack; Cordes, E.H.; Landers, M.N.

1985-01-01

A comprehensive study and development of measuring instruments and techniques for measuring all components of flow in a storm-sewer drainage system was undertaken by the U.S. Geological Survey under the sponsorship of the Federal Highway Administration. The study involved laboratory and field calibration and testing of measuring flumes, pipe insert meters, weirs, electromagnetic velocity meters as well as the development and calibration of pneumatic-bubbler pressure transducer head measuring systems. Tracer-dilution and acoustic flow meter measurements were used in field verification tests. A single micrologger was used to record data from all the above instruments as well as from a tipping-bucket rain gage and also to activate on command the electromagnetic velocity meter and tracer-dilution systems. (Author 's abstract)

Effect of dilute magnetic ions on the optical, dielectric and ferroelectric properties of PZT at morphotopic phase boundary

NASA Astrophysics Data System (ADS)

Rao, T. Lakshmana; Pradhan, M. K.; Ramakrishna, P. V.; Dash, S.

2018-05-01

Modified-PZT ceramics with a formula Pb0.9Ni0.1[(Zr0.52Ti0.48)]1-xSnxO3 located near the morphotropic phase boundary (MPB) were prepared by conventional solid state process to investigate effects of dilute doping of Ni and Sn in different sites of PZT. The single phase structure of the series of samples has been identified by x-ray diffraction technique. The optical band gap has been obtained from the UV-Vis spectra and found to be shrinkage with doping. The detail dielectric and impedance studies are being carried out to investigate the conduction mechanism of the samples. A significant enhancement in the electric polarization is observed for the maximum Sn doping in a modified PZT.

Tire with Self-Repairing Mechanism

NASA Astrophysics Data System (ADS)

Nagaya, Kosuke; Ikai, Sigeo; Chiba, Manabu; Chao, Xujing

A new type of tire is presented, in which there is no air leakage when nails puncture the tire. The broken part is repaired automatically by a self-repairing mechanism. The self-repairing unit consists of two rubber sheets with internal lattices. Polymer particles, which expand their volume on adding water, are inserted into the lattices. The unit is adhered to the inside wall of the tire. Coolant fluid diluted with water is introduced to the polymers uniformly. In this system, the polymer particles expand with water-diluted coolant fluid, and become gel. Hence, they stop air leakages in the tire. Fundamental experiments are performed, and optimum conditions are found. This technique is also applied to real tires, and it is ascertained that there is no air leakage when the tire is punctured by nails.

Fun Microbiology: Using a Plant Pathogenic Fungus To Demonstrate Koch's Postulates.

ERIC Educational Resources Information Center

Mitchell, James K.; Orsted, Kathy M.; Warnes, Carl E.

1997-01-01

Describes an experiment using a plant pathogenic fungus in which students learn to follow aseptic techniques, grow and produce spores of a fungus, use a hemacytometer for enumerating spores, prepare serial dilutions, grow and inoculate plants, isolate a pure culture using agar streak plates, and demonstrate the four steps of Koch's postulates.…

Historical biome distribution and recent human disturbance shape the diversity of arbuscular mycorrhizal fungi.

PubMed

Pärtel, Meelis; Öpik, Maarja; Moora, Mari; Tedersoo, Leho; Szava-Kovats, Robert; Rosendahl, Søren; Rillig, Matthias C; Lekberg, Ylva; Kreft, Holger; Helgason, Thorunn; Eriksson, Ove; Davison, John; de Bello, Francesco; Caruso, Tancredi; Zobel, Martin

2017-10-01

The availability of global microbial diversity data, collected using standardized metabarcoding techniques, makes microorganisms promising models for investigating the role of regional and local factors in driving biodiversity. Here we modelled the global diversity of symbiotic arbuscular mycorrhizal (AM) fungi using currently available data on AM fungal molecular diversity (small subunit (SSU) ribosomal RNA (rRNA) gene sequences) in field samples. To differentiate between regional and local effects, we estimated species pools (sets of potentially suitable taxa) for each site, which are expected to reflect regional processes. We then calculated community completeness, an index showing the fraction of the species pool present, which is expected to reflect local processes. We found significant spatial variation, globally in species pool size, as well as in local and dark diversity (absent members of the species pool). Species pool size was larger close to areas containing tropical grasslands during the last glacial maximum, which are possible centres of diversification. Community completeness was greater in regions of high wilderness (remoteness from human disturbance). Local diversity was correlated with wilderness and current connectivity to mountain grasslands. Applying the species pool concept to symbiotic fungi facilitated a better understanding of how biodiversity can be jointly shaped by large-scale historical processes and recent human disturbance. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Trail-following in termites: Evidence for a multicomponent system.

PubMed

Kaib, M; Bruinsma, O; Leuthold, R H

1982-09-01

Several African termite species from different subfamilies and different habitats are sensitive to trail-active extracts or to naturally laid trails from other species. Using single-extract bioassays, it is shown that the response threshold for trail-following is nearly identical for all tested species (except forHodotermes mossambicus). However, when termite workers have a choice between trails from their own species and from other species, conspecific trail-following is exclusively observed. This phenomenon can be counteracted by dilution (1∶10) of the conspecific trail-pheromone extract. Tests of the trail activity of various synthetic alcohols show that among these, the highest sensitivity of termite workers is to (Z)-3-dodecen-1-ol. Based on our experimental data, we postulate that, in addition to a generally active trail-pheromone constituent (an unsaturated primary C12 alcohol) or a pool of chemically closely related alcohols, other species-specific components are present in termite trails.

Generation of genome-modified Drosophila cell lines using SwAP.

PubMed

Franz, Alexandra; Brunner, Erich; Basler, Konrad

2017-10-02

The ease of generating genetically modified animals and cell lines has been markedly increased by the recent development of the versatile CRISPR/Cas9 tool. However, while the isolation of isogenic cell populations is usually straightforward for mammalian cell lines, the generation of clonal Drosophila cell lines has remained a longstanding challenge, hampered by the difficulty of getting Drosophila cells to grow at low densities. Here, we describe a highly efficient workflow to generate clonal Cas9-engineered Drosophila cell lines using a combination of cell pools, limiting dilution in conditioned medium and PCR with allele-specific primers, enabling the efficient selection of a clonal cell line with a suitable mutation profile. We validate the protocol by documenting the isolation, selection and verification of eight independently Cas9-edited armadillo mutant Drosophila cell lines. Our method provides a powerful and simple workflow that improves the utility of Drosophila cells for genetic studies with CRISPR/Cas9.

Quantitative Analysis and Stability of the Rodenticide TETS ...

EPA Pesticide Factsheets

Journal Article The determination of the rodenticide tetramethylenedisulfotetramine (TETS) in drinking water is reportable through the use of automated sample preparation via solid phase extraction and detection using isotope dilution gas chromatography-mass spectrometry. The method was characterized over twenty-two analytical batches with quality control samples. Accuracies for low and high concentration quality control pools were 100 and 101%, respectively. The minimum reporting level (MRL) for TETS in this method is 0.50 ug/L. Five drinking waters representing a range of water quality parameters and disinfection practices were fortified with TETS at ten times the MRL and analyzed over a 28 day period to determine the stability of TETS in these waters. The amount of TETS measured in these samples averaged 100 ± 6% of the amount fortified suggesting that tap water samples may be held for up to 28 days prior to analysis.

Seepage investigation using geophysical techniques at Coursier Lake Dam, B.C., Canada

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

Sirles, P.

1997-10-01

Subsurface seepage flow at Coursier Lake Dam was identified by onshore and offshore self-potential surveys, and electrical resistivity profiles and soundings during a Deficiency Investigation by BChydro. For typical seepage investigations baseline geophysical data are collected at {open_quotes}low-pool{close_quotes} level and the measurements are repeated when high hydraulic gradient conditions exist. At Coursier Lake Dam a rather unanticipated outcome of the low-pool surveys was that significant seepage beneath the structure was detected. The low-pool results were conclusive enough that, when combined with visual inspection and observation of sinkholes on the embankment, an immediate restriction was placed on the pool elevation. Thus,more » because of the identified potential hazard, the remaining geophysical investigations were conducted under a {open_quotes}minimum-pool{close_quotes} reservoir level in order to complete the comparative study. Therefore, the dam was studied under low- and minimum-pool reservoir conditions in the spring and fall of 1993, respectively. Low-pool data indicated very high resistivities (3000 to 5000 ohm-m) throughout the embankment indicating a coarse-average grain size, probably unsaturated sands and gravels. Higher resistivities (>5000 ohm-m) were obtained within the foundation deposits along the downstream toe indicating a combination of lower moisture content, coarser average grain size and higher porosity than the embankment. These electrical data indicate the subsurface conditions in the embankment and the foundation to be conducive to seepage. Results from low-pool SP surveys, performed both on-shore and offshore, indicate a dispersed or sheet flow seepage occurring nearly 1100 feet upstream of the intake. Therefore, apparently the seepage source begins far upstream of the embankment within the foundation deposits.« less

Development, standardization and validation of molecular techniques for malaria vector species identification, trophic preferences, and detection of Plasmodium falciparum.

PubMed

Rath, Animesha; Prusty, Manas R; Barik, Sushanta K; Das, Mumani; Tripathy, Hare K; Mahapatra, Namita; Hazra, Rupenangshu K

2017-01-01

Knowledge on prevalence of malaria vector species of a certain area provides important information for implementation of appropriate control strategies. The present study describes a rapid method for screening of major Anopheline vector species and at the same time detection of Plasmodium falciparum sporozoite infection and blood meal preferences/trophic preferences. The study was carried from February 2012 to March 2013 in three seasons, i.e. rainy, winter and summer in Jhumpura PHC of Keonjhar district, Odisha, India. Processing of mosquitoes was carried out in two different methods, viz. mosquito pool (P1) and mosquito DNA pool (P2). Pool size for both the methods was standardized for DNA isolation and multiplex PCR assay. This PCR based assay was employed to screen the major vector com- position in three different seasons of four different ecotypes of Keonjhar district. Pearson's correlation coefficient was determined for a comparative analysis of the morphological identification with the pool prevalence assay for each ecotype. A pool size of 10 was standardized for DNA isolation as well as PCR. PCR assay revealed that the average pool prevalence for all ecotypes was highest for An. annularis in winter and summer whereas for An. culicifacies it was rainy season. Foothill and plain ecotypes contributed to highest and lowest vectorial abundance respectively. The results of the prevalence of vector species in pool from PCR based assay were found to be highly correlated with that of the results of morphological identification. Screening by pool based PCR assay is relatively rapid as compared to conventional identification and can be employed as an important tool in malaria control programmes.

Capture of the volatile carbonyl metabolite of flecainide on 2,4-dinitrophenylhydrazine cartridge for quantitation by stable-isotope dilution mass spectrometry coupled with chromatography

PubMed Central

Prokai, Laszlo; Szarka, Szabolcs; Wang, Xiaoli; Prokai-Tatrai, Katalin

2012-01-01

Carbonyl compounds are common byproducts of many metabolic processes. These volatile chemical entities are usually derivatized before mass spectrometric analysis to enhance the sensitivity of their detections. The classically used reagent for this purpose is 2,4-dinitrophenylhydrazine (DNPH) that forms the corresponding hydrazones. When DNPH is immobilized on specific cartridges it permits solvent-free collection and simultaneous derivatization of aldehydes and ketones from gaseous samples. The utility of this approach was tested by assembling a simple apparatus for the in vitro generation of trifluoroacetaldehyde (TFAA) and its subsequent capture on the attached DNPH cartridge. TFAA was generated via cytochrome P450-catalyzed dealkylation of flecainide, an antiarrhythmic agent, in pooled human liver microsomes. Stable-isotope dilution mass spectrometry coupled with GC and LC using negative chemical ionization (NCI) and electrospray ionization (ESI) was evaluated for quantitative analyses. To eliminate isotope effects observed with the use of deuterium-labeled DNPH, we selected its 15N4-labeled analog to synthesize the appropriate TFAA adduct, as internal standard. Quantitation by GC–NCI-MS using selected-ion monitoring outperformed LC–ESI-MS methods considering limits of detection and linearity of the assays. The microsomal metabolism of 1.5 μmol of flecainide for 1.5 h resulted in 2.6 ± 0.5 μg TFAA-DNPH, corresponding to 9.3 ± 1.7 nmol TFAA, captured by the cartridge. PMID:22342210

Capture of the volatile carbonyl metabolite of flecainide on 2,4-dinitrophenylhydrazine cartridge for quantitation by stable-isotope dilution mass spectrometry coupled with chromatography.

PubMed

Prokai, Laszlo; Szarka, Szabolcs; Wang, Xiaoli; Prokai-Tatrai, Katalin

2012-04-06

Carbonyl compounds are common byproducts of many metabolic processes. These volatile chemicals are usually derivatized before mass spectrometric analysis to enhance the sensitivity of their detections. The classically used reagent for this purpose is 2,4-dinitrophenylhydrazine (DNPH) that forms the corresponding hydrazones. When DNPH is immobilized on specific cartridges it permits solvent-free collection and simultaneous derivatization of aldehydes and ketones from gaseous samples. The utility of this approach was tested by assembling a simple apparatus for the in vitro generation of trifluoroacetaldehyde (TFAA) and its subsequent capture on the attached DNPH cartridge. TFAA was generated via cytochrome P450-catalyzed dealkylation of flecainide, an antiarrhythmic agent, in pooled human liver microsomes. Stable-isotope dilution mass spectrometry coupled with GC and LC using negative chemical ionization (NCI) and electrospray ionization (ESI) was evaluated for quantitative analyses. To eliminate isotope effects observed with the use of deuterium-labeled DNPH, we selected its (15)N(4)-labeled analog to synthesize the appropriate TFAA adduct, as internal standard. Quantitation by GC-NCI-MS using selected-ion monitoring outperformed LC-ESI-MS methods considering limits of detection and linearity of the assays. The microsomal metabolism of 1.5 μmol of flecainide for 1.5h resulted in 2.6 ± 0.5 μg TFAA-DNPH, corresponding to 9.3 ± 1.7 nmol TFAA, captured by the cartridge. Copyright © 2012 Elsevier B.V. All rights reserved.

Ambient-temperature incubation for the field detection of Escherichia coli in drinking water.

PubMed

Brown, J; Stauber, C; Murphy, J L; Khan, A; Mu, T; Elliott, M; Sobsey, M D

2011-04-01

 Escherichia coli is the pre-eminent microbiological indicator used to assess safety of drinking water globally. The cost and equipment requirements for processing samples by standard methods may limit the scale of water quality testing in technologically less developed countries and other resource-limited settings, however. We evaluate here the use of ambient-temperature incubation in detection of E. coli in drinking water samples as a potential cost-saving and convenience measure with applications in regions with high (>25°C) mean ambient temperatures.   This study includes data from three separate water quality assessments: two in Cambodia and one in the Dominican Republic. Field samples of household drinking water were processed in duplicate by membrane filtration (Cambodia), Petrifilm™ (Cambodia) or Colilert® (Dominican Republic) on selective media at both standard incubation temperature (35–37°C) and ambient temperature, using up to three dilutions and three replicates at each dilution. Matched sample sets were well correlated with 80% of samples (n = 1037) within risk-based microbial count strata (E. coli CFU 100 ml−1 counts of <1, 1–10, 11–100, 101–1000, >1000), and a pooled coefficient of variation of 17% (95% CI 15–20%) for paired sample sets across all methods.   These results suggest that ambient-temperature incubation of E. coli in at least some settings may yield sufficiently robust data for water safety monitoring where laboratory or incubator access is limited.

Ex vivo 12 h bactericidal activity of oral co-amoxiclav (1.125 g) against beta-lactamase-producing Haemophilus influenzae.

PubMed

Bronner, S; Pompei, D; Elkhaïli, H; Dhoyen, N; Monteil, H; Jehl, F

2001-10-01

The aim of the study was to evaluate the in vitro/ex vivo bactericidal activity of a new coamoxiclav single-dose sachet formulation (1 g amoxicillin + 0.125 g clavulanic acid) against a beta-lactamase-producing strain of Haemophilus influenzae. The evaluation covered the 12 h period after antibiotic administration. Serum specimens from the 12 healthy volunteers included in the pharmacokinetic study were pooled by time point and in equal volumes. Eight of 12 pharmacokinetic sampling time points were included in the study. At time points 0.5, 0.75, 1, 1.5, 2.5, 5, 8 and 12 h post-dosing, the kinetics of bactericidal activity were determined for each of the serial dilutions. Each specimen was serially diluted from 1:2 to 1:256. The index of surviving bacteria (ISB) was subsequently determined for each pharmacokinetic time point. For all the serum samples, bactericidal activity was fast (3-6 h), marked (3-6 log(10) reduction in the initial inoculum) and sustained over the 12 h between-dosing interval. The results obtained also confirmed that the potency of the amoxicillin plus clavulanic acid combination was time dependent against the species under study and that the time interval over which the concentrations were greater than the MIC (t > MIC) was 100% for the strain under study. The data thus generated constitute an interesting prerequisite with a view to using co-amoxiclav 1.125 g in a bd oral regimen.

Boar spermatozoa encapsulated in barium alginate membranes: a microdensitometric evaluation of some enzymatic activities during storage at 18 degrees C.

PubMed

Faustini, Massimo; Torre, Maria Luisa; Stacchezzini, Simona; Norberti, Roberta; Consiglio, Anna Lange; Porcelli, Franca; Conte, Ubaldo; Munari, Eleonora; Russo, Vincenzo; Vigo, Daniele

2004-01-01

The customary dilution of boar semen for subsequent artificial insemination (AI) procedures damages the cell membrane of spermatozoa, resulting in a loss of enzymes and other cytoplasmic contents and acrosomal reactions. We encapsulated non-diluted boar semen in barium alginate membranes to optimize AI procedures and to improve the functional integrity of spermatozoal membranes during storage. The percentage of non-reacted acrosomes (NRA) and measurements of enzyme leakage (cytochrome c oxidase (COX), lactate dehydrogenase (LDH), and glucose-6-phosphate dehydrogenase (G6PDH)) were used as indices of the functional status of diluted, unencapsulated and encapsulated spermatozoa, stored for 72 h at 18 degrees C. Enzymatic activity was assessed in situ by microdensitometry, and non-reacted acrosomes were microscopically determined by staining. The percentage of acrosome integrity and the intracellular enzymatic activities during storage were different for unencapsulated and encapsulated semen. Semen dilution caused a rapid decline in enzymatic activities and concomitant acrosomal reactions. Encapsulated spermatozoa had significantly higher acrosome integrity (77% versus 55%; P < 0.01 after 72 h) and an overall higher in situ enzymatic activity. For cytochrome c oxidase and lactate dehydrogenase the greatest differences between encapsulated and unencapsulated spermatozoa were present after 72 h whereas for glucose-6-phosphate dehydrogenase significant differences were found within 24h of storage. The encapsulation process maintains a better preservation environment for boar spermatozoa and could be a promising, innovative technique to improve storage of these cells.

Rapid detection of semenogelin by one-step immunochromatographic assay for semen identification.

PubMed

Sato, Itaru; Kojima, Koichiro; Yamasaki, Tadashi; Yoshida, Kaoru; Yoshiike, Miki; Takano, Shoichi; Mukai, Toshiji; Iwamoto, Teruaki

2004-04-01

To identify semen in forensic samples, we developed an analytical system for one-step immunoassay that has been constructed using the concept of immunochromatography and can identify semenogelin (Sg), which originates in the seminal vesicles. The system employed monoclonal antibody (mAb) and polyclonal antibody (pAb) against recombinant Sg-II (63 kDa), which has been synthesized in insect cells using baculovirus. The two antibodies bound with the seminal plasma motility inhibitor (SPMI; 14 kDa) as a final fragment peptide of Sg. The test stick is based on the sandwich technique using the above antibodies. When serial dilutions of seminal plasma were analyzed using this test stick, the intensity of a clear immunoreactive signal peaked at 2000-fold dilution. Thereafter, the signals decreased slowly but still persisted up to 400,000-fold dilution. The Sg antigen was undetectable in saliva, urine, breast milk, serum or vaginal secretions. Also, the test stick shown did not react with animal semen samples, such as those from horses, dogs, swine and bulls. When semen samples, diluted 100,000-fold from 100 men were tested, the Sg antigenic activity was detectable in all samples. In addition, the specificity and sensitivity of the test stick for identification of semen were demonstrated by comparative forensic studies. We conclude that this immunoassay method is a useful confirmatory test for the identification of semen. The immunochromatographic system for forensic testing or research use will become available commercially soon.

An improved method for undertaking limiting dilution assays for in vitro cloning of Plasmodium falciparum parasites.

PubMed

Butterworth, Alice S; Robertson, Alan J; Ho, Mei-Fong; Gatton, Michelle L; McCarthy, James S; Trenholme, Katharine R

2011-04-18

Obtaining single parasite clones is required for many techniques in malaria research. Cloning by limiting dilution using microscopy-based assessment for parasite growth is an arduous and labor-intensive process. An alternative method for the detection of parasite growth in limiting dilution assays is using a commercial ELISA histidine-rich protein II (HRP2) detection kit. Detection of parasite growth was undertaken using HRP2 ELISA and compared to thick film microscopy. An HRP2 protein standard was used to determine the detection threshold of the HRP2 ELISA assay, and a HRP2 release model was used to extrapolate the amount of parasite growth required for a positive result. The HRP2 ELISA was more sensitive than microscopy for detecting parasite growth. The minimum level of HRP2 protein detection of the ELISA was 0.11 ng/ml. Modeling of HRP2 release determined that 2,116 parasites are required to complete a full erythrocytic cycle to produce sufficient HRP2 to be detected by the ELISA. Under standard culture conditions this number of parasites is likely to be reached between 8 to 14 days of culture. This method provides an accurate and simple way for the detection of parasite growth in limiting dilution assays, reducing time and resources required in traditional methods. Furthermore the method uses spent culture media instead of the parasite-infected red blood cells, enabling culture to continue. © 2011 Butterworth et al; licensee BioMed Central Ltd.

Investigation of wintertime cold-air pools and aerosol layers in the Salt Lake Valley using a lidar ceilometer

NASA Astrophysics Data System (ADS)

Young, Joseph Swyler

This thesis investigates the utility of lidar ceilometers, a type of aerosol lidar, in improving the understanding of meteorology and air quality in persistent wintertime stable boundary layers, or cold-air pools, that form in urbanized valley and basin topography. This thesis reviews the scientific literature to survey the present knowledge of persistent cold-air pools, the operating principles of lidar ceilometers, and their demonstrated utility in meteorological investigations. Lidar ceilometer data from the Persistent Cold-Air Pool Study (PCAPS) are then used with meteorological and air quality data from other in situ and remote sensing equipment to investigate cold-air pools that formed in Utah's Salt Lake Valley during the winter of 2010-2011. The lidar ceilometer is shown to accurately measure aerosol layer depth and aerosol loading, when compared to visual observations. A linear relationship is found between low-level lidar backscatter and surface particulate measurements. Convective boundary layer lidar analysis techniques applied to cold-air pool ceilometer profiles can detect useful layer characteristics. Fine-scale waves are observed and analyzed within the aerosol layer, with emphasis on Kelvin-Helmholz waves. Ceilometer aerosol backscatter profiles are analyzed to quantify and describe mixing processes in persistent cold-air pools. Overlays of other remote and in-situ observations are combined with ceilometer particle backscatter to describe specific events during PCAPS. This analysis describes the relationship between the aerosol layer and the valley inversion as well as interactions with large-scale meteorology. The ceilometer observations of hydrometers are used to quantify cloudiness and precipitation during the project, observing that 50% of hours when a PCAP was present had clouds or precipitation below 5 km above ground level (AGL). Then, combining an objective technique for determining hourly aerosol layer depths and correcting this subjectively during periods with low clouds or precipitation, a time series of aerosol depths was obtained. The mean depth of the surface-based aerosol layer during PCAP events was 1861 m MSL with a standard deviation of 135 m. The aerosol layer depth, given the approximate 1300 m altitude of the valley floor, is thus about 550 m, about 46% of the basin depth. The aerosol layer is present during much of the winter and is removed only during strong or prolonged precipitation periods or when surface winds are strong. Nocturnal fogs that formed near the end of high-stability PCAP episodes had a limited effect on aerosol layer depth. Aerosol layer depth was relatively invariant during the winter and during the persistent cold-air pools, while PM10 concentrations at the valley floor varied with bulk atmospheric stability associated primarily with passage of large-scale high- and low-pressure weather systems. PM10 concentrations also increased with cold-air pool duration. Mean aerosol loading in the surface-based aerosol layer, as determined from ceilometer backscatter coefficients, showed weaker variations than those of surface PM10 concentrations, suggesting that ineffective vertical mixing and aerosol layering are present in the cold-air pools. This is supported by higher time-resolution backscatter data, and it distinguishes the persistent cold-air pools from well-mixed convective boundary layers where ground-based air pollution concentrations are closely related to time-dependent convective boundary layer/aerosol depths. These results are discussed along with recommendations for future explorations of the ceilometer and cold-air pool topics.

Comparison of susceptibility test methods to detect penicillin susceptibility in Streptococcus pneumoniae isolates.

PubMed

Mohd Nasir, Mohd Desa; Parasakthi, Navaratnam

2004-06-01

The increasing prevalence of penicillin-resistant Streptococuus pneumoniae urges for fast and accurate susceptibility testing methods. This study evaluated the comparability of three commonly used techniques; disk diffusion, E-test and agar dilution, to detect penicillin susceptibility in clinical isolates of S. pneumoniae. Fifty pneumococcal isolates, obtained from patients at the University of Malaya Medical Centre, were selected to include both penicillin-susceptible strains and those that had decreased susceptibility (resistant and intermediate) to penicillin. The minimum inhibitory concentration (MIC) values of penicillin to serve as the reference was determined by the agar dilution method in which, based on the MIC breakpoints recommended by the National Committee for Clinical Laboratory Standards (NCCLS), 27 strains had decreased susceptibility to penicillin with 17 strains resistant and 10 intermediate. Comparing to the agar dilution method, oxacillin disk diffusion test detected all strains with decreased penicillin susceptibility as such while E-test showed a close agreement of susceptibility (92%) of the isolates to penicillin. This confirmed that oxacillin is a good screening test for S. pneumoniae isolates with decreased susceptibility to penicillin while E-test is very reliable for rapid and accurate detection of penicillin susceptibility.

Opalescence in monoclonal antibody solutions and its correlation with intermolecular interactions in dilute and concentrated solutions.

PubMed

Raut, Ashlesha S; Kalonia, Devendra S

2015-04-01

Opalescence indicates physical instability of a formulation because of the presence of aggregates or liquid-liquid phase separation in solution and has been reported for monoclonal antibody (mAb) formulations. Increased solution opalescence can be attributed to attractive protein-protein interactions (PPIs). Techniques including light scattering, AUC, or membrane osmometry are routinely employed to measure PPIs in dilute solutions, whereas opalescence is seen at relatively higher concentrations, where both long- and short-range forces contribute to overall PPIs. The mAb molecule studied here shows a unique property of high opalescence because of liquid-liquid phase separation. In this study, opalescence measurements are correlated to PPIs measured in diluted and concentrated solutions using light scattering (kD ) and high-frequency rheology (G'), respectively. Charges on the molecules were calculated using zeta potential measurements. Results indicate that high opalescence and phase separation are a result of the attractive interactions in solution; however, the presence of attractive interactions do not always imply phase separation. Temperature dependence of opalescence suggests that thermodynamic contribution to opalescence is significant and Tcloud can be utilized as a potential tool to assess attractive interactions in solution. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Inoculation of Bacillus sphaericus UPMB-10 to Young Oil Palm and Measurement of Its Uptake of Fixed Nitrogen Using the 15N Isotope Dilution Technique

PubMed Central

Zakry, Fitri Abdul Aziz; Shamsuddin, Zulkifli H.; Rahim, Khairuddin Abdul; Zakaria, Zin Zawawi; Rahim, Anuar Abdul

2012-01-01

There are increasing applications of diazotrophic rhizobacteria in the sustainable agriculture system. A field experiment on young immature oil palm was conducted to quantify the uptake of N derived from N2 fixation by the diazotroph Bacillus sphaericus strain UPMB-10, using the 15N isotope dilution method. Eight months after 15N application, young immature oil palms that received 67% of standard N fertilizer application together with B. sphaericus inoculation had significantly lower 15N enrichment than uninoculated palms that received similar N fertilizers. The dilution of labeled N served as a marker for the occurrence of biological N2 fixation. The proportion of N uptake that was derived from the atmosphere was estimated as 63% on the whole plant basis. The inoculation process increased the N and dry matter yields of the palm leaflets and rachis significantly. Field planting of young, immature oil palm in soil inoculated with B. sphaericus UPMB-10 might mitigate inorganic fertilizer-N application through supplementation by biological nitrogen fixation. This could be a new and important source of nitrogen biofertilizer in the early phase of oil palm cultivation in the field. PMID:22446306

Observations of axisymmetric tracer particle orientation during flow through a dilute fixed bed of fibers

NASA Astrophysics Data System (ADS)

Frattini, Paul L.; Shaqfeh, Eric S. G.; Levy, Jeffrey L.; Koch, Donald L.

1991-11-01

Direct microstructural evidence for net tracer particle orientation induced solely by hydrodynamic interactions in a dilute, disordered, fibrous media is reported. A dilute fixed bed of randomly placed fibers was constructed and glycerol/water suspensions of either synthetic akaganeite (βFeOOH, average aspect ratio 6.3) or hematite (αFe2O3, average aspect ratio 1.6) tracer particles were made to flow axially through the bed at prescribed flow rates. Conservative linear dichroism, a noninvasive light scattering technique, was employed to provide a direct measure of the orientational order parameter for the tracer particle population at the end of the bed. The effect of Brownian motion on the hydrodynamically induced order in the suspensions was studied over three orders of magnitude in scaled rotary Peclet number, 5

Analysis of deoxyribonucleotide pools in human cancer cell lines using a liquid chromatography coupled with tandem mass spectrometry technique

PubMed Central

Zhang, Wei; Tan, Shenglan; Paintsil, Elijah; Dutschman, Ginger E.; Gullen, Elizabeth A.; Chu, Edward; Cheng, Yung-Chi

2011-01-01

Endogenous ribonucleotides and deoxyribonucleotides play a critical role in cell function, and determination of their levels is of fundamental importance in understanding key cellular processes involved in energy metabolism and molecular and biochemical signaling pathways. In this study, we determined the respective ribonucleotide and deoxyribonucleotide pool sizes in different human cell lines using a simple sample preparation method and LC/MS/MS. This assay was used to determine alterations in deoxyribonucleotide pools in human pancreatic PANC-1 cells in response to hypoxia and to treatment with either hydroxyurea or aphidicolin. The levels of all deoxyribonucleotide metabolites decreased with hypoxia treatment, except for dUMP, which increased by two-fold. This LC/MS/MS assay is simple, fast, and sensitive, and it represents a significant advance over previously published methodologies. PMID:21620803

Discussion on runoff purification technology of highway bridge deck based on water quality safety

NASA Astrophysics Data System (ADS)

Tan, Sheng-guang; Liu, Xue-xin; Zou, Guo-ping; Xiong, Xin-zhu; Tao, Shuang-cheng

2018-06-01

Aiming at the actual problems existing, including a poor purification effect of highway bridge runoff collection and treatment system across sensitive water and necessary manual emergency operation, three kinds of technology, three pools system of bridge runoff purification, the integral pool of bridge runoff purification and ecological planting tank, are put forward by optimizing the structure of purification unit and system setting. At the same time, we come up with an emergency strategy for hazardous material leakage basing on automatic identification and remote control of traffic accidents. On the basis of combining these with the optimized pool structure, sensitive water safety can be guaranteed and water pollution, from directly discharging of bridge runoff, can be decreased. For making up for the shortages of green highway construction technology, the technique has important reference value.

Protocols for Biotechnological Interventions in Improvement of Vanilla (Vanilla planifolia Andrews.).

PubMed

Divakaran, Minoo; Babu, K Nirmal; Peter, K V

2016-01-01

Vanilla (Vanilla planifolia Andrews (syn. V. fragrans Salisb.), a native of Central America, is the primary source of natural vanillin and plays a major role in the global economy. The gene pool of vanilla is threatened by deforestation and overcollection that has resulted in disappearance of natural habitats and wild species. Continuous vegetative propagation and lack of natural seed set and sufficient variations in the gene pool hamper crop improvement programs. In vitro techniques, one of the key tools of plant biotechnology, can be employed for overcoming specific problems, viz. production of disease-free clones, inducing somaclonal variations, developing hybrids, gene pool conservation, incorporating desired traits by distant hybridization, genetic engineering, etc. However, realization of these objectives necessitates standardization of protocols. This chapter describes the various protocols optimized for crop improvement in Vanilla species.

Kick, Stroke and Swim: Complement Your Swimming Program by Engaging the Whole Body on Dry Land and in the Pool

ERIC Educational Resources Information Center

Flynn, Susan; Duell, Kelly; Dehaven, Carole; Heidorn, Brent

2017-01-01

The Kick, Stroke and Swim (KSS) program can be used to engage students in swimming-skill acquisition and fitness training using a variety of modalities, strategies and techniques on dry land. Practicing swim strokes and techniques on land gives all levels of swimmers--from beginner to competitive--a kinesthetic awareness of the individual…

Transgenic expression of human heme oxygenase-1 in pigs confers resistance against xenograft rejection during ex vivo perfusion of porcine kidneys.

PubMed

Petersen, Björn; Ramackers, Wolf; Lucas-Hahn, Andrea; Lemme, Erika; Hassel, Petra; Queisser, Anna-Lisa; Herrmann, Doris; Barg-Kues, Brigitte; Carnwath, Joseph W; Klose, Johannes; Tiede, Andreas; Friedrich, Lars; Baars, Wiebke; Schwinzer, Reinhard; Winkler, Michael; Niemann, Heiner

2011-01-01

The major immunological hurdle to successful porcine-to-human xenotransplantation is the acute vascular rejection (AVR), characterized by endothelial cell (EC) activation and perturbation of coagulation. Heme oxygenase-1 (HO-1) and its derivatives have anti-apoptotic, anti-inflammatory effects and protect against reactive oxygen species, rendering HO-1 a promising molecule to control AVR. Here, we report the production and characterization of pigs transgenic for human heme oxygenase-1 (hHO-1) and demonstrate significant protection in porcine kidneys against xenograft rejection in ex vivo perfusion with human blood and transgenic porcine aortic endothelial cells (PAEC) in a TNF-α-mediated apoptosis assay. Transgenic and non-transgenic PAEC were tested in a TNF-α-mediated apoptosis assay. Expression of adhesion molecules (ICAM-1, VCAM-1, and E-selectin) was measured by real-time PCR. hHO-1 transgenic porcine kidneys were perfused with pooled and diluted human AB blood in an ex vivo perfusion circuit. MHC class-II up-regulation after induction with IFN-γ was compared between wild-type and hHO-1 transgenic PAEC. Cloned hHO-1 transgenic pigs expressed hHO-1 in heart, kidney, liver, and in cultured ECs and fibroblasts. hHO-1 transgenic PAEC were protected against TNF-α-mediated apoptosis. Real-time PCR revealed reduced expression of adhesion molecules like ICAM-1, VCAM-1, and E-selectin. These effects could be abrogated by the incubation of transgenic PAECs with the specific HO-1 inhibitor zinc protoporphorine IX (Zn(II)PPIX, 20 μm). IFN-γ induced up-regulation of MHC class-II molecules was significantly reduced in PAECs from hHO-1 transgenic pigs. hHO-1 transgenic porcine kidneys could successfully be perfused with diluted human AB-pooled blood for a maximum of 240 min (with and without C1 inh), while in wild-type kidneys, blood flow ceased after ∼60 min. Elevated levels of d-Dimer and TAT were detected, but no significant consumption of fibrinogen and antithrombin was determined. Microthrombi could not be detected histologically. These results are encouraging and warrant further studies on the biological function of heme oxygenase-I expression in hHO-1 transgenic pigs in the context of xenotransplantation. © 2011 John Wiley & Sons A/S.

A randomized comparative crossover study to assess the affect on circuit life of varying pre-dilution volume associated with CVVH and CVVHDF.

PubMed

Davies, H T; Leslie, G; Pereira, S M; Webb, S A R

2008-03-01

To determine if circuit life is influenced by a higher pre-dilution volume used in CVVH when compared with a lower pre-dilution volume approach in CVVHDF. A comparative crossover study. Cases were randomized to receive either CVVH or CVVHDF followed by the alternative treatment. All patients >or= 18 yrs of age who required CRRT while in ICU were eligible to participate, but excluded if coagulopathic, thrombocytopenic or unable to receive heparin. Based on an intention-to-treat, 45 patients were randomized to receive either CVVH or CVVHDF followed by the alternative treatment. A 24-bed, tertiary, medical and surgical adult intensive care unit (ICU). Blood flow rate, vascular access device and insertion site, hemofilter, anticoagulation and machine hardware were standardized. An ultrafiltrate dose of 35 ml/ kg/h delivered pre-filter was used for CVVH. A fixed pre-dilution volume of 600 mls/h with a dialysate dose of 1 L was used for CVVHDF. Thirty-one patients received CVVH or CVVHDF out of 45 participants followed by the alternative technique. There was a significant increase in circuit life in favor of CVVHDF (median=16 h 5 min, range=40 h 23 min) compared with CVVH (median=6 h 35 min, range=30 h 45 min). A Mann-Whitney U test was performed to compare circuit life between the two different CRRT modes (Z=-3.478, p<0.001). Measurements of circuit life on the 93 circuits which survived to clotting (50 CVVH and 43 CVVHDF) were log transformed prior to under taking a standard multiple regression analysis. None of the independent variables - activated prothrombin time (aPTT), platelet count, heparin dose, patient hematocrit or urea - had a coefficient partial correlation >0.09 (coefficient of the determination=0.117) or a linear relationship which could be associated with circuit life (p=0.228). Pre-diluted CVVHDF appeared to have a longer circuit life when compared to high volume pre-diluted CVVH. The choice of CRRT mode may be an important independent determinant of circuit life.

The subunit structure of horse spleen apoferritin: the molecular weight of the oligomer and its stability to dissociation by dilution (Short Communication)

PubMed Central

Crichton, Robert R.; Eason, Robert; Barclay, Allan; Bryce, Charles F. A.

1973-01-01

The oligomer molecular weight of horse spleen apoferritin was determined by sedimentation-equilibrium techniques and a value of 443000 found. It is concluded that the apoferritin molecule consists of 24 subunits. At concentrations as low as 0.01μm there is no evidence of subunit dissociation. PMID:4737327

Room temperature magnetism and metal to semiconducting transition in dilute Fe doped Sb1-xSex semiconducting alloy thin films

NASA Astrophysics Data System (ADS)

Agrawal, Naveen; Sarkar, Mitesh; Chawda, Mukesh; Ganesan, V.; Bodas, Dhananjay

2015-02-01

The magnetism was observed in very dilute Fe doped alloy thin film Fe0.008Sb1-xSex, for x = 0.01 to 0.10. These thin films were grown on silicon substrate using thermal evaporation technique. Structural, electrical, optical, charge carrier concentration measurement, surface morphology and magnetic properties were observed using glancing incidence x-ray diffraction (GIXRD), four probe resistivity, photoluminescence, Hall measurement, atomic force microscopy (AFM) and magnetic force microscopy (MFM) techniques, respectively. No peaks of iron were seen in GIXRD. The resistivity results show that activation energy increases with increase in selenium (Se) concentration. The Arrhenius plot reveals metallic behavior below room temperature. The low temperature conduction is explained by variable range-hopping mechanism, which fits very well in the temperature range 150-300 K. The decrease in density of states has been observed with increasing selenium concentration (x = 0.01 to 0.10). There is a metal-to-semiconductor phase transition observed above room temperature. This transition temperature is Se concentration dependent. The particle size distribution ˜47-61 nm is evaluated using AFM images. These thin films exhibit ferromagnetic interactions at room temperature.

An evaluation of tracer dilution techniques for gauging of rivers in flood

NASA Astrophysics Data System (ADS)

Airey, P. L.; Calf, G. E.; Davison, A.; Easey, J. F.; Morley, A. W.

1984-10-01

The use of the tracer dilution technique to gauge flow over broad shallow floodplains is examined. Because of the long mixing lengths, it sometimes takes several days for the passage of the laterally dispersed pulse. Tracer methods can be used if the flow rates vary linearly during the passage of the pulse. The measured flow rate is related to the time at which the first moment of the concentration profile (∫ tc( z, t)d t) is zero. An experimental verification is presented. By analysing the tracer pulse shapes before the establishment of complete mixing, it was demonstrated that the effective dispersion coefficients were independent of the scale of turbulence over the range 10 m to ˜1 km. This is consistent with the establishment of isotropic turbulence on the floodplain in contrast to oceanic surfaces. The velocity of the tracer is a factor of 2 less than that of an advancing wave front, which is in acceptable agreement with prediction. It is concluded that the transport of a non-interacting contaminant across the floodplain can be predicted from the wave front velocity and the dispersion coefficients measured close to the release point.

Determination of Aspartame and Caffeine in Carbonated Beverages Utilizing Electrospray Ionization-Mass Spectrometry

NASA Astrophysics Data System (ADS)

Bergen, H. Robert, III; Benson, Linda M.; Naylor, Stephen

2000-10-01

Mass spectrometry has undergone considerable changes in the past decade. The advent of "soft ionization" techniques such as electrospray ionization (ESI) affords the direct analysis of very polar molecules without need for the complex inefficient derivatization procedures often required in GC-MS. These ionization techniques make possible the direct mass spectral analysis of polar nonvolatile molecules such as DNA and proteins, which previously were difficult or impossible to analyze by MS. Compounds that readily take on a charge (acids and bases) lend themselves to ESI-MS analysis, whereas compounds that do not readily accept a charge (e.g. sugars) are often not seen or are seen only as inefficient adducts (e.g., M+Na+). To gain exposure to this state-of-the-art analytical procedure, high school students utilize ESI-MS in an analysis of aspartame and caffeine. They dilute a beverage sample and inject the diluted sample into the ESI-MS. The lab is procedurally simple and the results clearly demonstrate the potential and limitations of ESI-coupled mass spectrometry. Depending upon the instructional goals, the outlined procedures can be used to quantify the content of caffeine and aspartame in beverages or to understand the capabilities of electrospray ionization.

Probing emissions of military cargo aircraft: description of a joint field measurement Strategic Environmental Research and Development Program.

PubMed

Cheng, Meng-Dawn; Corporan, Edwin; DeWitt, Matthew J; Spicer, Chester W; Holdren, Michael W; Cowen, Kenneth A; Laskin, Alex; Harris, David B; Shores, Richard C; Kagann, Robert; Hashmonay, Ram

2008-06-01

To develop effective air quality control strategies for military air bases, there is a need to accurately quantify these emissions. In support of the Strategic Environmental Research and Development Program project, the particulate matter (PM) and gaseous emissions from two T56 engines on a parked C-130 aircraft were characterized at the Kentucky Air National Guard base in Louisville, KY. Conventional and research-grade instrumentation and methodology were used in the field campaign during the first week of October 2005. Particulate emissions were sampled at the engine exit plane and at 15 m downstream. In addition, remote sensing of the gaseous species was performed via spectroscopic techniques at 5 and 15 m downstream of the engine exit. It was found that PM mass and number concentrations measured at 15-m downstream locations, after dilution-correction generally agreed well with those measured at the engine exhaust plane; however, higher variations were observed in the far-field after natural dilution of the downstream measurements was accounted for. Using carbon dioxide-normalized data we demonstrated that gas species measurements by extractive and remote sensing techniques agreed reasonably well.

Magnetic Control of Concentration Gradient in Microgravity

NASA Technical Reports Server (NTRS)

Leslie, Fred; Ramachandran, Narayanan

2005-01-01

A report describes a technique for rapidly establishing a fluid-concentration gradient that can serve as an initial condition for an experiment on solutal instabilities associated with crystal growth in microgravity. The technique involves exploitation of the slight attractive or repulsive forces exerted on most fluids by a magnetic-field gradient. Although small, these forces can dominate in microgravity and therefore can be used to hold fluids in position in preparation for an experiment. The magnetic field is applied to a test cell, while a fluid mixture containing a concentration gradient is prepared by introducing an undiluted solution into a diluting solution in a mixing chamber. The test cell is then filled with the fluid mixture. Given the magnetic susceptibilities of the undiluted and diluting solutions, the magnetic-field gradient must be large enough that the magnetic force exceeds both (1) forces associated with the flow of the fluid mixture during filling of the test cell and (2) forces imposed by any residual gravitation and fluctuations thereof. Once the test cell has been filled with the fluid mixture, the magnetic field is switched off so that the experiment can proceed, starting from the proper initial conditions.

A direct observation technique for evaluating sclerotium germination by Macrophomina phaseolina and effects of biocontrol materials on survival of sclerotia in soil.

PubMed

Pratt, Robert G

2006-08-01

Germination of sclerotia of Macrophomina phaseolina was quantified by direct microscopic observation following application of experimental treatments in vitro and incubation of sclerotia in soil. To assay germination, pieces of agar containing sclerotia were macerated in dilute, liquid cornmeal agar on glass slides; thinly spread; and incubated in a saturated atmosphere for 18-22 h. Germinated sclerotia then were identified by morphological features of germ hyphae. Frequencies of germination were similar in three dilute agar media. Germination was not affected by air-drying sclerotia for 2 weeks, but it was significantly reduced after 4 weeks and greatly reduced or eliminated after 6 or 8 weeks. Survival of sclerotia for 14 days in soil was greatest at 50, 75, and 100% moisture-holding capacity, less at 0 and 25%, and least at 125% (flooded soil). Incorporation of ground poultry litter into soil at 5% by weight reduced survival of sclerotia after 13 days, and incorporation of litter at 10% nearly eliminated it. These results indicate that the direct-observation technique may be used to evaluate animal wastes and other agricultural byproducts for biocontrol activity against sclerotia of M. phaseolina in soil.

[Comparison between the LightCycler CMV Quant Kit (Roche Diagnostics) with a standardized in-house Taqman assay for cytomegalovirus blood viral load quantification].

PubMed

Alain, S; Lachaise, V; Hantz, S; Denis, F

2010-04-01

The broad use of cytomegalovirus (CMV) viral load quantification in blood to follow immunosuppressed patients need standardized assays. Choice of whole blood allows follow-up for several viruses and simplifies pretreatment and storage of samples. We therefore evaluated the LightCycler CMV Quant Kit (Roche Diagnostics) assay on whole blood after a manual extraction (High Pure viral nucleic acid kit, Roche Diagnostics), using as a reference an in-house Taqman assay (LC1UL83) which has been validated in various clinical situations. A panel obtained by serial dilutions of a virion stock in CMV whole blood, a commercial plasma quality control (VQC, Argène, France) crude or diluted in whole blood, infected cells extracts and 46 clinical samples from transplanted patients were tested simultaneously by both techniques. For plasma quality controls, both PCR assays are correlated VQC (R(2)=0.93). On whole blood or infected cells dilutions, correlation shows an overestimation by the LC1UL83 assay (mean 1.2 log copies/ml) over 3 log though R(2)=0.94. Results with CMV Quant Kit are closer to expected values. Results on clinical samples are close to quality controls with a lower variation of quantification (0.76 log copies/ml). CMV Quant Kit performs well when compared with a clinically validated PCR. Quality control results showed discrepancies between plasma and whole blood, demonstrating the need for whole blood standardized panels to compare the methods. This underlines the need to follow a patient with the same technique during his follow-up. Copyright 2009 Elsevier Masson SAS. All rights reserved.

Volume quantification by contrast-enhanced ultrasound: an in-vitro comparison with true volumes and thermodilution.

PubMed

Herold, Ingeborg H F; Russo, Gianna; Mischi, Massimo; Houthuizen, Patrick; Saidov, Tamerlan; van het Veer, Marcel; van Assen, Hans C; Korsten, Hendrikus H M

2013-10-17

Contrast-enhanced ultrasound (CEUS) has recently been proposed as a minimally- invasive, alternative method for blood volume measurement. This study aims at comparing the accuracy of CEUS and the classical thermodilution techniques for volume assessment in an in-vitro set-up. The in-vitro set-up consisted of a variable network between an inflow and outflow tube and a roller pump. The inflow and outflow tubes were insonified with an ultrasound array transducer and a thermistor was placed in each tube. Indicator dilution curves were made by injecting indicator which consisted of an ultrasound-contrast-agent diluted in ice-cold saline. Both acoustic intensity- and thermo-dilution curves were used to calculate the indicator mean transit time between the inflow and outflow tube. The volumes were derived by multiplying the estimated mean transit time by the flow rate. We compared the volumes measured by CEUS with the true volumes of the variable network and those measured by thermodilution by Bland-Altman and intraclass-correlation analysis. The measurements by CEUS and thermodilution showed a very strong correlation (rs = 0.94) with a modest volume underestimation by CEUS of -40 ± 28 mL and an overestimation of 84 ± 62 mL by thermodilution compared with the true volumes. Both CEUS and thermodilution showed a high statistically significant correlation with the true volume (rs = 0.97 (95% CI, 0.95 - 0.98; P<0.0001) and rs = 0.96 (95% CI, 0.94 - 0.98; P<0.0001, respectively). CEUS volume estimation provides a strong correlation with both the true volumes in-vitro and volume estimation by thermodilution. It may therefore represent an interesting alternative to the standard, invasive thermodilution technique.

Rapid transcapillary exchange and unidirectional neuronal uptake of noradrenaline in the perfused rabbit heart.

PubMed Central

Mann, G E; Yudilevich, D L

1984-01-01

Capillary permeability and cellular uptake of noradrenaline by the isolated artificially perfused rabbit heart was measured using rapid (less than 30 s) single-circulation tracer-dilution techniques. In a single coronary circulation capillary extractions of L-[14C]noradrenaline and D-[3H]mannitol (extracellular reference) relative to an intravascular marker, 125I-labelled albumin, were similar and above 60%. The 'apparent' volume of distribution for tracer noradrenaline was 2.5-fold larger than that measured for D-mannitol (0.32 ml g-1) suggesting cellular uptake of the amine. Unidirectional noradrenaline uptake was estimated by directly comparing coronary sinus dilution profiles of L-[3H]noradrenaline and D-[14C]mannitol. Michaelis-Menten saturation kinetics based on a single-entry system were determined (Km = 2.8 +/- 1.5 microM, Vmax = 2.1 +/- 0.5 nmol min-1 g-1, n = 4) by perfusing hearts with varying concentrations of L-noradrenaline (1-10 microM). Various known inhibitors of noradrenaline uptake were investigated to determine whether uptake was mediated by neuronal (uptake1) and/or extraneuronal (uptake2) mechanisms. Desipramine (5 microM), imipramine (5 microM) and metaraminol (2 microM) resulted in a 66-94% inhibition of noradrenaline influx. In comparison, the steroids, 17 beta-oestradiol (1 microM) and corticosterone (10 microM), and the noradrenaline metabolite normetanephrine (5 microM) caused virtually no inhibitory effects. The beta-adrenergic antagonist propranolol (5 microM) was also relatively ineffective. These results together with the kinetic constants estimated suggest that the rapid noradrenaline uptake reflects transport into adrenergic neurones lying in the coronary interstitium. The high resolution of this paired-tracer dilution technique has permitted a 'non-invasive' study of neuronal uptake mechanisms and its application may be of clinical value. PMID:6425496

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

Liang, Shuhua; Bishop, Christopher B.; Moreo, Adriana

The phase diagram of electron-doped pnictides is studied varying the temperature, electronic density, and isotropic in-plane quenched disorder strength and dilution by means of computational techniques applied to a three-orbital (xz,yz,xy) spin-fermion model with lattice degrees of freedom. In experiments, chemical doping introduces disorder but in theoretical studies the relationship between electronic doping and the randomly located dopants, with their associated quenched disorder, is difficult to address. Moreover, in this publication, the use of computational techniques allows us to study independently the effects of electronic doping, regulated by a global chemical potential, and impurity disorder at randomly selected sites. Surprisingly,more » our Monte Carlo simulations reveal that the fast reduction with doping of the N eel T N and the structural T S transition temperatures, and the concomitant stabilization of a robust nematic state, is primarily controlled in our model by the magnetic dilution associated with the in-plane isotropic disorder introduced by Fe substitution. In the doping range studied, changes in the Fermi surface produced by electron doping affect only slightly both critical temperatures. Our results also suggest that the specific material-dependent phase diagrams experimentally observed could be explained as a consequence of the variation in disorder profiles introduced by the different dopants. Finally, our findings are also compatible with neutron scattering and scanning tunneling microscopy, unveiling a patchy network of locally magnetically ordered clusters with anisotropic shapes, even though the quenched disorder is locally isotropic. Our study reveals a remarkable and unexpected degree of complexity in pnictides: the fragile tendency to nematicity intrinsic of translational invariant electronic systems needs to be supplemented by quenched disorder and dilution to stabilize the robust nematic phase experimentally found in electron-doped 122 compounds.« less

Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. II. Formation and decomposition of thiosulfate and polythionate in Cinder Pool

NASA Astrophysics Data System (ADS)

Xu, Y.; Schoonen, M. A. A.; Nordstrom, D. K.; Cunningham, K. M.; Ball, J. W.

2000-04-01

Cinder Pool is an acid-sulfate-chloride boiling spring in Norris Geyser Basin, Yellowstone National Park. The pool is unique in that its surface is partially covered with mm-size, black, hollow sulfur spherules, while a layer of molten sulfur resides at the bottom of the pool (18 m depth). The sulfur speciation in the pool was determined on four different days over a period of two years. Samples were taken to evaluate changes with depth and to evaluate the importance of the sulfur spherules on sulfur redox chemistry. All analyses were conducted on site using a combination of ion chromatography and colorimetric techniques. Dissolved sulfide (H2S), thiosulfate (S2O32-), polythionates (SxO62-), and sulfate were detected. The polythionate concentration was highly variable in time and space. The highest concentrations were found in surficial samples taken from among the sulfur spherules. With depth, the polythionate concentrations dropped off. The maximum observed polythionate concentration was 8 μM. Thiosulfate was rather uniformly distributed throughout the pool and concentrations ranged from 35 to 45 μM. Total dissolved sulfide concentrations varied with time, concentrations ranged from 16 to 48 μM. Sulfate was relatively constant, with concentrations ranging from 1150 to 1300 μM. The sulfur speciation of Cinder Pool is unique in that the thiosulfate and polythionate concentrations are significantly higher than for any other acid-sulfate spring yet sampled in Yellowstone National Park. Complementary laboratory experiments show that thiosulfate is the intermediate sulfoxyanion formed from sulfur hydrolysis under conditions similar to those found in Cinder Pool and that polythionates are formed via the oxidation of thiosulfate by dissolved oxygen. This last reaction is catalyzed by pyrite that occurs as a minor constituent in the sulfur spherules floating on the pool's surface. Polythionate decomposition proceeds via two pathways: (1) a reaction with H2S, yielding thiosulfate and elemental sulfur; and (2) by disproportionation to sulfate and thiosulfate. This study demonstrates that the presence of a subaqueous molten sulfur pool and sulfur spherules in Cinder Pool is of importance in controlling the pathways of aqueous sulfur redox reactions. Some of the insights gained at Cinder Pool may be relevant to acid crater lakes where sulfur spherules are observed and variations in polythionate concentrations are used to monitor and predict volcanic activity.

A simple and specific procedure to permeabilize the plasma membrane of Schizosaccharomyces pombe.

PubMed

Chardwiriyapreecha, Soracom; Hondo, Kana; Inada, Hiroko; Chahomchuen, Thippayarat; Sekito, Takayuki; Iwaki, Tomoko; Kakinuma, Yoshimi

2009-09-01

Cu(2+)-treatment is a useful technique in selectively permeabilizing the fungal plasma membrane. We describe herein a practical application with Schizosaccharomyces pombe. Incubation of cells with 0.5 mM CuCl(2) at 30 degrees C for 20 min induced efficient leakage of cytosolic constituents. The kinetic characteristics of the calcium and amino acid flux from Cu(2+)-treated S. pombe cells suggested that the Cu(2+) treatment permeabilized the plasma membrane without loss of vacuolar function. As a further application of the method, the amino acid contents of Cu(2+)-treated and untreated cells were also determined. The amino acid pool of Cu(2+)-treated wild-type cells was enriched in basic amino acids but not in acidic amino acids, as is characteristic of the vacuolar amino acid pool of fungi, including Saccharomyces cerevisiae and Neurosporra crassa. The amino acid pool of the S. pombe V-ATPase mutant vma1Delta was also successfully determined. We conclude that the vacuolar amino acid pool of S. pombe can be measured using Cu(2+)-treated cells. The method is simple, inexpensive, and rapid relative to the isolation of vacuolar vesicles, making it useful in estimating vacuolar pools and transport across the vacuolar membrane.

An Experimental Study on Burning Characteristics of n-Heptane/Ethanol Mixture Pool Fires in a Reduced Scaled Tunnel

NASA Astrophysics Data System (ADS)

Yozgatligil, Ahmet; Shafee, Sina

2016-11-01

Fire accidents in recent decades have drawn attention to safety issues associated with the design, construction and maintenance of tunnels. A reduced scale tunnel model constructed based on Froude scaling technique is used in the current work. Mixtures of n-heptane and ethanol are burned with ethanol volumetric fraction up to 30 percent and the longitudinal ventilation velocity varying from 0.5 to 2.5 m/s. The burning rates of the pool fires are measured using a precision load cell. The heat release rates of the fires are calculated according to oxygen calorimetry method and the temperature distributions inside the tunnel are also measured. Results of the experiments show that the ventilation velocity variation has a significant effect on the pool fire burning rate, smoke temperature and the critical ventilation velocity. With increased oxygen depletion in case of increased ethanol content of blended pool fires, the quasi-steady heat release rate values tend to increase as well as the ceiling temperatures while the combustion duration decreases.

Hot-wire Laser Welding of Deep and Wide Gaps

NASA Astrophysics Data System (ADS)

Näsström, J.; Frostevarg, J.; Silver, T.

Heavy section Gas Metal Arc Welding (GMAW) usually requires special edge preparation and several passes. One alternative for increased performance is Laser Arc Hybrid Welding (LAHW). For very thick sheets however, imperfections like root drops or solidification cracks can occur. In this study, other techniques are also studied, including multi-pass filling of deep gaps with wire deposition. A laser is then used to melt the filler and base material. The hot- and cold wire laser welding processes are highly sensitive to wire-laser positioning, where controlled melting of the wire is essential. Apart from a comprehensive literature survey, preliminary experiments were also performed in order to find a novel method variant that can successfully fill deep and wide gaps. The method applied uses a defocused laser that generates the melt pool. A resistance heated wire is fed into the melt pool front in a leading position. This is similar to additive manufacturing techniques such as laser direct metal deposition with wire. A layer height of several millimeters can be achieved and rather low laser power can be chosen. The preliminary experiments were observed using high speed imaging and briefly evaluated by visual examination of the resulting beads. Using a defocused laser beam turned out to have two major advantages; 1. It adds heat to the melt pool in a manner that properly fuses the bottom and walls of the base material. 2. It counteracts difficulties due to an irregularly oscillating filler wire. These early results show that this can be a promising technique for joining thick steels with wide gaps.

Expanding living kidney donor criteria with ex-vivo surgery for renal anomalies

PubMed Central

McGregor, Thomas B.; Rampersad, Christie; Patel, Premal

2016-01-01

Introduction: Renal transplantation remains the gold standard treatment for end-stage renal disease, with living donor kidneys providing the best outcomes in terms of allograft survival. As the number of patients on the waitlist continues to grow, solutions to expand the donor pool are ongoing. A paradigm shift in the eligibility of donors with renal anomalies has been looked at as a potential source to expand the living donor pool. We sought to determine how many patients presented with anatomic renal anomalies at our transplant centre and describe the ex-vivo surgical techniques used to render these kidneys suitable for transplantation. Methods: A retrospective review was performed of all patients referred for surgical suitability to undergo laparoscopic donor nephrectomy between January 2011 and January 2015. Patient charts were analyzed for demographic information, perioperative variables, urological histories, and postoperative outcomes. Results: 96 referrals were identified, of which 81 patients underwent laparoscopic donor nephrectomy. Of these patients, 11 (13.6%) were identified as having a renal anomaly that could potentially exclude them from the donation process. These anomalies included five patients with unilateral nephrolithiasis, four patients with large renal cysts (>4 cm diameter), one patient with an angiomyolipoma (AML) and one patient with a calyceal diverticulum filled with stones. A description of the ex-vivo surgical techniques used to correct these renal anomalies is provided. Conclusions: We have shown here that ex-vivo surgical techniques can safely and effectively help correct some of these renal anomalies to render these kidneys transplantable, helping to expand the living donor pool. PMID:27800047

AN ATTEMPT TO LOCATE INTERMETALLIC PARTICLES IN ZIRCONIUM ALLOYS USING A BITTER FIGURE TECHNIQUE

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

Cox, B.; Harder, B.R.

1961-10-01

The compound ZrFe/sub 2/ is known to be ferromagnetic, and an attempt to locate particles of magnetic material in zircaloy-2 and dilute Zr- Fe alloys by a Bitter figure technlque is described. An Fe/sub 3/O/sub 4/ sol in water-soluble plastic was used to prepare Bitter figures of the alloy surfaces in the form of replicas, which were then examined in an electron microscope. No magnetic particles were located in either zircaloy-2 or a Zr-O.3% Fe alloy. Subsequent work on specimens of ZrFe/sub 2/ showed that the failure to detect it in the dilute alloys arose because the size of themore » intermetallic particles in the latter was smaller than the size of the magnetic domains. (auth)« less

Validation of an isotope dilution, ICP-MS method based on internal mass bias correction for the determination of trace concentrations of Hg in sediment cores.

PubMed

Ciceri, E; Recchia, S; Dossi, C; Yang, L; Sturgeon, R E

2008-01-15

The development and validation of a method for the determination of mercury in sediments using a sector field inductively coupled plasma mass spectrometer (SF-ICP-MS) for detection is described. The utilization of isotope dilution (ID) calibration is shown to solve analytical problems related to matrix composition. Mass bias is corrected using an internal mass bias correction technique, validated against the traditional standard bracketing method. The overall analytical protocol is validated against NRCC PACS-2 marine sediment CRM. The estimated limit of detection is 12ng/g. The proposed procedure was applied to the analysis of a real sediment core sampled to a depth of 160m in Lake Como, where Hg concentrations ranged from 66 to 750ng/g.

Water Purification

NASA Technical Reports Server (NTRS)

1994-01-01

The Vision Catalyst Purifier employs the basic technology developed by NASA to purify water aboard the Apollo spacecraft. However, it also uses an "erosion" technique. The purifier kills bacteria, viruses, and algae by "catalytic corrosion." A cartridge contains a silver-impregnated alumina bed with a large surface area. The catalyst bed converts oxygen in a pool of water to its most oxidative state, killing over 99 percent of the bacteria within five seconds. The cartridge also releases into the pool low levels of ionic silver and copper through a controlled process of erosion. Because the water becomes electrochemically active, no electricity is required.

Financing Higher Education after Tax Reform.

ERIC Educational Resources Information Center

Anderson, Richard E.; Meyerson, Joel W.

1987-01-01

Capital finance, once limited to financing physical plant, today includes all assets and aspects of institutional life. It now encompasses a wide range of approaches and techniques including pooled debt, capital leases, futures contracts, equity investments, and research partnerships. (MLW)

Construction of crack-free bridge decks.

DOT National Transportation Integrated Search

2017-04-01

This serves as the final report on Transportation Pooled-Fund Program Project No. TPF-5(174), Construction : of Crack-Free Bridge Decks. The goal of the study was to implement the most cost-effective techniques for : improving bridge deck life ...

Trihalomethanes in Lisbon indoor swimming pools: occurrence, determining factors, and health risk classification.

PubMed

Silva, Zelinda Isabel; Rebelo, Maria Helena; Silva, Manuela Manso; Alves, Ana Martins; Cabral, Maria da Conceição; Almeida, Ana Cristina; Aguiar, Fátima Rôxo; de Oliveira, Anabela Lopes; Nogueira, Ana Cruz; Pinhal, Hermínia Rodrigues; Aguiar, Pedro Manuel; Cardoso, Ana Sofia

2012-01-01

Characterization of water quality from indoor swimming pools, using chorine-based disinfection techniques, was performed during a 6-mo period to study the occurrence, distribution, and concentration factors of trihalomethanes (THM). Several parameters such as levels of water THM, water and air chloroform, water bromodichloromethane (BDCM), water dibromochloromethane (DBCM), water bromoform (BF), free residual chlorine (FrCl), pH, water and air temperature, and permanganate water oxidizability (PWO) were determined in each pool during that period. Chloroform (CF(W)) was the THM detected at higher concentrations in all pools, followed by BDCM, DBCM, and BF detected at 99, 34, and 6% of the samples, respectively. Water THM concentrations ranged from 10.1 to 155 μg/L, with 6.5% of the samples presenting values above 100 μg/L (parametric value established in Portuguese law DL 306/2007). In this study, air chloroform (CF(Air)) concentrations ranged from 45 to 373 μg/m³ with 24% of the samples presenting values above 136 μg/m³ (considered high exposure value). Several significant correlations were observed between total THM and other parameters, namely, CF(W), CF(Air), FrCl, water temperature (T(W)), and PWO. These correlations indicate that FrCl, T(W) and PWO are parameters that influence THM formation. The exposure criterion established for water THM enabled the inclusion of 67% of Lisbon pools in the high exposure group, which reinforces the need for an improvement in pool water quality.

A hot-cracking mitigation technique for welding high-strength aluminum alloy

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

Yang, Y.P.; Dong, P.; Zhang, J.

2000-01-01

A hot-cracking mitigation technique for gas tungsten arc welding (GTAW) of high-strength aluminum alloy 2024 is presented. The proposed welding technique incorporates a trailing heat sink (an intense cooling source) with respect to the welding torch. The development of the mitigation technique was based on both detailed welding process simulation using advanced finite element techniques and systematic laboratory experiments. The finite element methods were used to investigate the detailed thermomechanical behavior of the weld metal that undergoes the brittle temperature range (BTR) during welding. As expected, a tensile deformation zone within the material BTR region was identified behind the weldmore » pool under conventional GTA welding process conventional GTA welding process conditions for the aluminum alloy studied. To mitigate hot cracking, the tensile zone behind the weld pool must be eliminated or reduce to a satisfactory level if the weld metal hot ductility cannot be further improved. With detailed computational modeling, it was found that by the introduction of a trailing heat sink at some distance behind the welding arc, the tensile strain rate with respect to temperature in the zone encompassing the BTR region can be significantly reduced. A series of parametric studies were also conducted to derive optimal process parameters for the trailing heat sink. The experimental results confirmed the effectiveness of the trailing heat sink technique. With a proper implementation of the trailing heat sink method, hot cracking can be completely eliminated in welding aluminum alloy 2024 (AA 2024).« less

Fascin Is Critical for the Maintenance of Breast Cancer Stem Cell Pool Predominantly via the Activation of the Notch Self-Renewal Pathway.

PubMed

Barnawi, Rayanah; Al-Khaldi, Samiyah; Majed Sleiman, Ghida; Sarkar, Abdullah; Al-Dhfyan, Abdullah; Al-Mohanna, Falah; Ghebeh, Hazem; Al-Alwan, Monther

2016-12-01

An emerging dogma shows that tumors are initiated and maintained by a subpopulation of cancer cells that hijack some stem cell features and thus referred to as "cancer stem cells" (CSCs). The exact mechanism that regulates the maintenance of CSC pool remains largely unknown. Fascin is an actin-bundling protein that we have previously demonstrated to be a major regulator of breast cancer chemoresistance and metastasis, two cardinal features of CSCs. Here, we manipulated fascin expression in breast cancer cell lines and used several in vitro and in vivo approaches to examine the relationship between fascin expression and breast CSCs. Fascin knockdown significantly reduced stem cell-like phenotype (CD44 hi /CD24 lo and ALDH + ) and reversal of epithelial to mesenchymal transition. Interestingly, expression of the embryonic stem cell transcriptional factors (Oct4, Nanog, Sox2, and Klf4) was significantly reduced when fascin expression was down-regulated. Functionally, fascin-knockdown cells were less competent in forming colonies and tumorspheres, consistent with lower basal self-renewal activity and higher susceptibility to chemotherapy. Fascin effect on CSC chemoresistance and self-renewability was associated with Notch signaling. Activation of Notch induced the relevant downstream targets predominantly in the fascin-positive cells. Limiting-dilution xenotransplantation assay showed higher frequency of tumor-initiating cells in the fascin-positive group. Collectively, our data demonstrated fascin as a critical regulator of breast CSC pool at least partially via activation of the Notch self-renewal signaling pathway and modification of the expression embryonic transcriptional factors. Targeting fascin may halt CSCs and thus presents a novel therapeutic approach for effective treatment of breast cancer. Stem Cells 2016;34:2799-2813 Video Highlight: https://youtu.be/GxS4fJ_Ow-o. © 2016 AlphaMed Press.

Theoretical modelling of AFM for bimetallic tip-substrate interactions

NASA Technical Reports Server (NTRS)

Bozzolo, Guillermo; Ferrante, John

1991-01-01

Recently, a new technique for calculating the defect energetics of alloys based on Equivalent Crystal Theory was developed. This new technique successfully predicts the bulk properties for binary alloys as well as segregation energies in the dilute limit. The authors apply this limit for the calculation of energy and force as a function of separation of an atomic force microscope (AFM) tip and substrate. The study was done for different combinations of tip and sample materials. The validity of the universality discovered for the same metal interfaces is examined for the case of different metal interactions.

Plasma volume methodology: Evans blue, hemoglobin-hematocrit, and mass density transformations

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Hinghofer-Szalkay, H.

1985-01-01

Methods for measuring absolute levels and changes in plasma volume are presented along with derivations of pertinent equations. Reduction in variability of the Evans blue dye dilution technique using chromatographic column purification suggests that the day-to-day variability in the plasma volume in humans is less than + or - 20 m1. Mass density determination using the mechanical-oscillator technique provides a method for measuring vascular fluid shifts continuously for assessing the density of the filtrate, and for quantifying movements of protein across microvascular walls. Equations for the calculation of volume and density of shifted fluid are presented.

Dynamics of polymers in elongational flow studied by the neutron spin-echo technique

NASA Astrophysics Data System (ADS)

Rheinstädter, Maikel C.; Sattler, Rainer; Häußler, Wolfgang; Wagner, Christian

2010-09-01

The nanoscale fluctuation dynamics of semidilute high molecular weight polymer solutions of polyethylenoxide (PEO) in D 2O under non-equilibrium flow conditions were studied by the neutron spin-echo technique. The sample cell was in contraction flow geometry and provided a pressure driven flow with a high elongational component that stretched the polymers most efficiently. Neutron scattering experiments in dilute polymer solutions are challenging because of the low polymer concentration and corresponding small quasi-elastic signals. A relaxation process with relaxation times of about 10 ps was observed, which shows anisotropic dynamics with applied flow.

Freezing-Out Technique Applied to the Concentration of Biologically Active Materials

PubMed Central

Wilson, T. E.; Evans, D. J.; Theriot, Mary L.

1964-01-01

When applied to a dilute solution of folic acid and glucose, a freezing-out (with agitation) technique was shown to be an effective method of achieving a 20-fold reduction in volume with a loss of 10% of the active material being concentrated. Concentration of a stimulatory factor for Lactobacillus casei produced by Candida albicans in a complex medium was limited by the total solute concentration. Salts in the medium were concentrated to levels inhibitory for L. casei. The process is not selective and all solutes are concentrated. Images FIG. 2 FIG. 3 PMID:14131370

Protective properties of anticholera antibodies in human colostrum.

PubMed Central

Majumdar, A S; Ghose, A C

1982-01-01

A comparative immunological study between two colostrum pools of Indian and Swedish mothers was carried out to evaluate their protective properties against Vibrio cholerae. Antibacterial and antitoxin titers were significantly higher in the Indian colostrum pool (ICP) than in the Swedish colostrum pool (SCP). Antilipopolysaccharide as well as antitoxin antibodies belonged to secretory immunoglobulin A (IgA) and IgM classes as determined by the enzyme-linked immunosorbent assay. ICP could significantly inhibit the adherence of V. cholerae to intestinal slices in vitro, whereas such activity was virtually absent in SCP. Moreover, ICP could induce significant protection against live vibrio challenge in rabbit ileal loops, whereas only a weak protective activity was observed with SCP. A secretory IgA fraction was obtained from ICP by using gel filtration and immunoadsorbent techniques. Human secretory IgA thus obtained exhibited antiadherence as well as protective activities against V. cholerae. PMID:7095856

Caldicellulosiruptor obsidiansis sp. nov., an anaerobic, extremely thermophilic, cellulolytic bacterium isolated from Obsidian Pool, Yellowstone National Park.

PubMed

Hamilton-Brehm, Scott D; Mosher, Jennifer J; Vishnivetskaya, Tatiana; Podar, Mircea; Carroll, Sue; Allman, Steve; Phelps, Tommy J; Keller, Martin; Elkins, James G

2010-02-01

A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47(T), was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 microm long by 0.2 microm wide and grew at temperatures between 55 and 85 degrees C, with the optimum at 78 degrees C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h(-1). The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47(T) was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H2, and CO2, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47(T) within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073).

Caldicellulosiruptor obsidiansis sp. nov., an Anaerobic, Extremely Thermophilic, Cellulolytic Bacterium Isolated from Obsidian Pool, Yellowstone National Park▿

PubMed Central

Hamilton-Brehm, Scott D.; Mosher, Jennifer J.; Vishnivetskaya, Tatiana; Podar, Mircea; Carroll, Sue; Allman, Steve; Phelps, Tommy J.; Keller, Martin; Elkins, James G.

2010-01-01

A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47T, was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 μm long by 0.2 μm wide and grew at temperatures between 55 and 85°C, with the optimum at 78°C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h−1. The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47T was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H2, and CO2, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47T within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073). PMID:20023107

A dual pathways transfer model to account for changes in the radioactive caesium level in demersal and pelagic fish after the Fukushima Daï-ichi nuclear power plant accident

PubMed Central

Bailly-du-Bois, Pascal; Laguionie, Philippe; Morillon, Mehdi; Arnaud, Mireille; Cunin, Pascal

2017-01-01

The Fukushima Daï-ichi nuclear power plant (FDNPP) accident resulted in radioactive Cs being discharged into the local marine environment. While Cs bioaccumulates in biota and slowly depurates, the Cs concentrated in biota constitutes a source of Cs for animals feeding on each other. The marine biota therefore serves as a pool that recycles Cs, and this recycling process delays depuration in the fish feeding on this biota pool. Because the continental shelf is squeezed between the coast and very deep sea, the demersal marine species are confined to a narrow strip along the coast, close to the source of the radioactive input. Unlike demersal species, however, pelagic species are not restricted to the most contaminated area but instead spend some, if not most, of their time and feeding off-shore, far from the input source. We suggest that the feeding pathway for fish is a box whose size depends on their mobility, and that this feeding box is much larger and less contaminated (because of dilution through distance) for pelagic fish than for demersal fish. The aim of this paper is to test this hypothesis and to propose a simple operational model implementing two transfer routes: from seawater and from feeding. The model is then used to match the observational data in the aftermath of the FDNPP accident. PMID:28248982

Modeling of Heat Transfer and Fluid Flow in the Laser Multilayered Cladding Process

NASA Astrophysics Data System (ADS)

Kong, Fanrong; Kovacevic, Radovan

2010-12-01

The current work examines the heat-and-mass transfer process in the laser multilayered cladding of H13 tool steel powder by numerical modeling and experimental validation. A multiphase transient model is developed to investigate the evolution of the temperature field and flow velocity of the liquid phase in the molten pool. The solid region of the substrate and solidified clad, the liquid region of the melted clad material, and the gas region of the surrounding air are included. In this model, a level-set method is used to track the free surface motion of the molten pool with the powder material feeding and scanning of the laser beam. An enthalpy-porosity approach is applied to deal with the solidification and melting that occurs in the cladding process. Moreover, the laser heat input and heat losses from the forced convection and heat radiation that occurs on the top surface of the deposited layer are incorporated into the source term of the governing equations. The effects of the laser power, scanning speed, and powder-feed rate on the dilution and height of the multilayered clad are investigated based on the numerical model and experimental measurements. The results show that an increase of the laser power and powder feed rate, or a reduction of the scanning speed, can increase the clad height and directly influence the remelted depth of each layer of deposition. The numerical results have a qualitative agreement with the experimental measurements.

Assessment of body fat in the pony: part II. Validation of the deuterium oxide dilution technique for the measurement of body fat.

PubMed

Dugdale, A H A; Curtis, G C; Milne, E; Harris, P A; Argo, C Mc

2011-09-01

Excessive accumulations or depletions of body fat have been associated with increased morbidity and mortality in horses and ponies. An objective, minimally-invasive method to accurately quantify body fat in living animals is required to aid nutritional management and define welfare/performance limits. To compare deuterium oxide (D(2) O) dilution-derived estimates of total body water (TBW) and body fat with values obtained by 'gold standard' proximate analysis and cadaver dissection. D(2) O dilution offers a valid method for the determination of TBW and body fat in equids. Seven mature (mean ± s.e. 13 ± 3 years, 212 ± 14 kg, body condition scores 1.25-7/9), healthy, Welsh Mountain pony mares, destined for euthanasia (for nonresearch purposes) were used. Blood samples were collected before and 4 h after D(2) O (0.11-0.13 g/kg bwt, 99.8 atom percent excess) administration. Plasma was analysed by gas isotope ratio mass spectrometry following filtration and zinc reduction. After euthanasia, white adipose tissue (WAT) mass was recorded before all body tissues were analysed by proximate chemical analyses. D(2) O-derived estimates of TBW and body fat were strongly associated with proximate analysis- and dissection-derived values (all r(2) >0.97, P≤0.0001). Bland-Altman analyses demonstrated good agreements between methods. D(2) O dilution slightly overestimated TBW (0.79%, limits of agreement (LoA) -3.75-2.17%) and underestimated total body lipid (1.78%, LoA -0.59-4.15%) and dissected WAT (0.72%, LoA -2.77-4.21%). This study provides the first validation of the D(2) O dilution method for the minimally-invasive, accurate, repeatable and objective measurement of body water and fat in living equids. © 2011 EVJ Ltd.

Aqueous penetration and biological activity of moxifloxacin 0.5% ophthalmic solution and gatifloxacin 0.3% solution in cataract surgery patients.

PubMed

Kim, Dianne H; Stark, Walter J; O'Brien, Terrence P; Dick, James D

2005-11-01

To measure the achievable perioperative aqueous concentration of the commercially available topically administered fourth generation fluoroquinolones, moxifloxacin 0.5% ophthalmic solution, and gatifloxacin 0.3% ophthalmic solution, and to correlate this concentration with the agents' biological efficacy in the aqueous humor of patients undergoing routine cataract surgery. Prospective, randomized, parallel, double-masked, clinical trial. Fifty patients undergoing cataract extraction. Patients (n = 25) were given perioperative topical moxifloxacin 0.5% or topical gatifloxacin 0.3% (n = 25). One drop of antibiotic was administered every 10 minutes for 4 doses beginning 1 hour prior to surgery. Aqueous humor was sampled via paracentesis and antibiotic concentrations were determined using validated high performance liquid chromatography (HPLC) procedures. Dilution analyses were performed to determine the biological efficacy of the agents in the aqueous against Staphylococcus epidermidis, the most common cause of postcataract endophthalmitis. Aqueous humor antibiotic concentrations were measured using HPLC and microdilution bioassay techniques. Biological activity was measured as minimal inhibitory dilution and minimal bactericidal dilution. Aqueous humor concentrations for moxifloxacin via HPLC analysis were 1.80 (+/-1.21) microg/ml, whereas those for gatifloxacin were 0.48 (+/-0.34) microg/ml. This 3.8-fold difference in aqueous humor antibiotic concentrations was statistically significant (P = 0.00003). Similarly, the biological dilution analysis of the aqueous humor samples showed that moxifloxacin attained an estimated activity of 2.1 microg/ml, whereas the gatifloxacin activity was approximately 0.4 mug/ml, which represented a 4.9-fold difference. This study demonstrated that after topically administered perioperative antibiotics with cataract surgery, moxifloxacin 0.5% ophthalmic solution achieved a statistically significantly higher concentration in aqueous humor compared with gatifloxacin (P = 0.00003). Results from the broth dilution analysis showed that moxifloxacin 0.5% was biologically more active against S. epidermidis than gatifloxacin 0.3% in aqueous humor after topical application. There were no adverse events reported, and incision wounds healed quickly and as expected.

Comparison of Screening Dilution and Automated Reading for Antinuclear Antibody Detection on HEP2 Cells in the Monitoring of Connective Tissue Diseases.

PubMed

Depincé-Berger, Anne E; Moreau, Amelie; Bossy, Virginie; Genin, Christian; Rinaudo, Melanie; Paul, Stephane

2016-09-01

Indirect immunofluorescence plays a major role in the detection of antinuclear antibodies (ANAs) and follow-up of their titers in the context of connective tissue diseases. Given the numerous unfavorable features of the conventional manual reading of HEP2 slides (need of time and expert morphologists for the reading, lack of standardization, subjectivity of the interpretation), the biomedical industry has developed automated techniques of slide preparation and microscope reading. We collected 49 sera beforehand analyzed by the conventional reading of slides. They were prepared again by QUANTA-Lyser(®) and reanalyzed in four different conditions: two dilutions of screening (1/40 and 1/80), two different systems of analysis, NOVA View(®) automated reading (INOVA Diagnostics), then confirmation by the operator, and conventional manual reading by two different qualified operators. The analysis was realized in blind of the first interpretation and clinical diagnosis. The sera were classified in four groups, on the basis of the results of the first analysis: negative sera (titer < 1/160; 11 patients), low positives (titer at 1/160; 18 patients), moderated positives (titers between 1/320 and 1/640; 10 patients), and strong positives (titers between 1/1,280 and 1/2,560; 10 patients). Among the 49 patients, 13 presented a connective tissue disease including 4 systemic scleroderma (SS), 3 rheumatoid arthritis (RA), 2 Goujerot-Sjogren (GS), 2 systemic lupus erythematosus (SLE), 1 polymyositis (PM), 1 Raynaud's syndrome (RS), and 1 CREST syndrome. One patient presented both an SLE and an SS. Regarding the screening dilution, the 1/40 dilution is less specific than the 1/80 dilution for both the systems of analysis (5.6% vs. 16.7% for the manual reading, and 27.8% vs. 50% for the automated reading). It also generates statistically more false positives (P = 0.037 for the conventional analysis and P = 0.003 for the automated system). The automated NOVA View(®) reading of slides allows a gain in specificity for both dilutions, and also statistically less false positives (P = 0.002 at the 1/40 and P = 0.0006 at the 1/80), and detriment of the sensitivity at the highest dilution (84.6% vs. 92.3% with manual reading). Thus, according to our analysis of 49 sera, the automated NOVA View(®) system of reading of slides at the dilution 1/80 seems to be a successful condition for the detection of ANAs on HEP2 cells, close to the significance (P = 0.067). The automated NOVA View(®) reading of slides allows saving time, and an improvement in the standardization. Nevertheless, it requires a confirmation by a qualified operator, to interpret mixed patterns in particular. © 2016 Wiley Periodicals, Inc.

Headspace solid phase microextraction--GC/C-IRMS for delta13CVPDB measurements of mono-aromatic hydrocarbons using EA-IRMS calibration.

PubMed

Ebongué, Véronique Woule; Geypens, Benny; Berglund, Michael; Taylor, Philip

2009-03-01

This work aims at comparing the delta(13)C(VPDB) of mono-aromatic hydrocarbons benzene, toluene, ethylbenzene and xylene isomers (BTEX) measured by elemental analyser (EA)-isotope ratio mass spectrometer (IRMS) with the delta(13)C(VPDB) measured on the same compounds by headspace solid phase microextraction - GC/C-IRMS (hSPME - GC/C-IRMS) with the final goal of using these compounds as internal standards on the latter system. The EA-IRMS measurements were done using calcium and lithium carbonate isotopic reference materials: NBS19 and L-SVEC for establishing the delta(13)C(VPDB) scale. The EA-IRMS measurements with helium dilution of a set of five reference materials (USGS40, USGS41, IAEA-CH-6, IAEA-CH-3 and IAEA-601) show systematic bias of 1 per thousand relative to their assigned values. This bias due to the dilution mechanism in the used ConfloII interface device could not be avoided. As the selected hydrocarbons: BTEX could not be analysed by EA-IRMS without helium dilution, their delta(13)C(VPDB) must be corrected from this observed bias using an external calibration. The CO(2) gas calibrated using EA-IRMS without helium dilution, was used as an in-house reference for the delta(13)C(VPDB) measurements of the BTEX by the hSPME - GC/C-IRMS system. The comparison made between the delta(13)C(VPDB) measured on the same BTEX compounds by EA-IRMS (with external calibration) and by hSPME - GC/C-IRMS techniques showed good agreement.

Analysis of Cyclic Variability of Heat Release for High-EGR GDI Engine Operation with Observations on Implications for Effective Control

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

Kaul, Brian C; Wagner, Robert M; Green Jr, Johney Boyd

2013-01-01

Operation of spark-ignition (SI) engines with high levels of charge dilution through exhaust gas recirculation (EGR) achieves significant engine efficiency gains while maintaining stoichiometric operation for compatibility with three-way catalysts. Dilution levels, however, are limited by cyclic variability-including significant numbers of misfires-that becomes more pronounced with increasing dilution. This variability has been shown to have both stochastic and deterministic components. Stochastic effects include turbulence, mixing variations, and the like, while the deterministic effect is primarily due to the nonlinear dependence of flame propagation rates and ignition characteristics on the charge composition, which is influenced by the composition of residual gasesmore » from prior cycles. The presence of determinism implies that an increased understanding the dynamics of such systems could lead to effective control approaches that allow operation near the edge of stability, effectively extending the dilution limit. This nonlinear dependence has been characterized previously for homogeneous charge, port fuel-injected (PFI) SI engines operating fuel-lean as well as with inert diluents such as bottled N2 gas. In this paper, cyclic dispersion in a modern boosted gasoline direct injection (GDI) engine using a cooled external EGR loop is examined, and the potential for improvement with effective control is evaluated through the use of symbol sequence statistics and other techniques from chaos theory. Observations related to the potential implications of these results for control approaches that could effectively enable engine operation at the edge of combustion stability are noted.« less

Cryopreservation of Indian red jungle fowl (Gallus gallus murghi) semen.

PubMed

Rakha, B A; Ansari, M S; Akhter, S; Hussain, I; Blesbois, E

2016-11-01

The population of red jungle fowl is declining and needs special attention for its conservation with suitable approaches. For ex situ in vitro conservation of Indian red jungle fowl, establishment of semen cryobank is an appropriate option, for which an extender with adequate retrieval capacity for functional spermatozoa is required. Therefore, studies were designed to evaluate a wide range of extenders for cryopreservation of Indian red jungle fowl (Gallus gallus murghi) sperm to achieve maximal post-thawed semen quality and fertility. For this purpose, semen from eight mature cocks were collected, initially evaluated (percent sperm motility, volume and concentration), pooled, assessed for motility, plasma membrane integrity, viability and acrosome integrity, and divided into six aliquots for dilution (1:5; 37°C) in Beltsville poultry, red fowl extender, Lake, EK, Tselutin poultry and chicken semen extenders. Diluted semen was cooled from 37°C to 4°C @ -0.275°C/min. Glycerol (20%) was added to chilled semen, equilibrated for 10min, filled in 0.5mL French straws, kept over LN 2 vapours for 10min and plunged into LN 2 and stored at -196°C. Percentages of motility, plasma membrane integrity, viability and acrosome integrity were higher (P<0.05) in red fowl extender at 0, 2 and 4h of incubation post-thaw. After cryopreservation and post-thawing at 37°C the highest (P<0.05) recovery rates and absolute livability index was also recorded in red fowl extender that was thus used for further artificial insemination of cooled-diluted (Liquid) and cryopreserved sperm. The no. of fertilized eggs (Liquid, 20.6±0.4; Cryopreserved, 12.6±0.5), percent fertility (86.7±2.2; 57.2±3.9), no. of hatched chicks (18.2±0.8; 10.0±0.3), percent hatch (76.5±2.7; 45.3±2.2) and hatchability of fertilized eggs (88.3±3.4; 79.6±3.4) were higher with sperm respectively freshly cooled-diluted or cryopreserved in red fowl extender. However, the rates obtained with frozen-thawed sperm were already successful for cryo-banking purpose and artificial insemination practice. In conclusion, we show the first fertility success obtained with cryopreserved Indian jungle fowl sperm. In addition, the red fowl extender is superior in maintaining the quality of Indian red jungle fowl cryopreserved sperm compared to Beltsville poultry, Lake, EK, Tselutin poultry and chicken semen extender. Copyright © 2016 Elsevier B.V. All rights reserved.

Syn-eruptive, soft-sediment deformation of dilute pyroclastic density current deposits: triggers from granular shear, dynamic pore pressure, ballistic impacts and shock waves

NASA Astrophysics Data System (ADS)

Douillet, G. A.; Taisne, B.; Tsang-Hin-Sun, È.; Müller, S. K.; Kueppers, U.; Dingwell, D. B.

2014-12-01

Soft-sediment deformation produces intriguing sedimentary structures and can occur in diverse environments and from a variety of triggers. From the observation of such structures and their interpretation in terms of trigger mechanisms, valuable information can be extracted about former conditions. Here we document examples of syn-eruptive deformation in dilute pyroclastic density current deposits. Outcrops from 6 different volcanoes have been compiled in order to provide a broad perspective on the variety of structures: Ubehebe craters (USA), Tungurahua (Ecuador), Soufrière Hills (Montserrat), Laacher See (Germany), Tower Hill and Purrumbete lake (both Australia). Isolated slumps as well as sinking pseudonodules are driven by their excess weight and occur after deposition but penecontemporaneous to the eruption. Isolated, cm-scale, overturned beds with vortex forms have been interpreted to be the signature of shear instabilities occurring at the boundary of two granular media. They may represent the frozen record of granular, pseudo Kelvin-Helmholtz instabilities. Their recognition can be a diagnostic for flows with a granular basal boundary layer. The occurrence of degassing pipes together with basal intrusive dikes suggest fluidization during flow stages, and can facilitate the development of Kelvin-Helmholtz structures. The occurrence at the base of flow units of injection dikes in some outcrops compared with suction-driven local uplifts in others indicates the role of dynamic pore pressure. Variations of the latter are possibly related to local changes between depletive and accumulative dynamics of flows. Ballistic impacts can trigger unconventional sags producing local displacement or liquefaction. Based on the deformation depth, these can yield precise insights into depositional unit boundaries. Such impact structures may also be at the origin of some of the steep truncation planes visible at the base of the so-called "chute and pool" structures. Finally, the passage of shock waves emanating from the vent may be preserved in the form of trains of isolated, fine-grained overturned beds which may disturb the surface bedding without occurrence of a sedimentation phase in the vicinity of a vent. Dilute pyroclastic density currents occur contemporaneously with seismogenic volcanic explosions. They are often deposited on steep slopes and can incorporate large amounts of water and gas in the sediment. They can experience extremely high sedimentation rates and may flow at the border between traction, granular and fluid-escape boundary zones. These are just some of the many possible triggers acting in a single environment, and reveal the potential for insights into the eruptive mechanisms of dilute pyroclastic density currents.

Development of a Cold Sterilant for Field Medical Use.

DTIC Science & Technology

1996-11-01

Dental Devices Using STERIS 20C at Use Dilution and Manual Soak Technique .............. 1086 Akron Rubber Development Laboratory Report 32918...simulated reuse protocol with lot P-2 of 25 months of age , a number of positives (i.e. sterilization failures) were noted, in particular for the...Ethylene propylene ELASTOMERS Brass Ethylene propylene diene Ethylene propylene diene ( EPDM ) ( EPDM ) Brass 360 Polyamide RTV 133 Nickel-plated Cooper

Chemiluminescent optical fiber immunosensor for the detection of anti-West Nile virus IgG.

PubMed

Herrmann, Sebastien; Leshem, Boaz; Landes, Shimi; Rager-Zisman, Bracha; Marks, Robert S

2005-03-31

An ELISA-based optical fiber methodology developed for the detection of anti-West Nile virus IgG antibodies in serum was compared to standard colorimetric and chemiluminescent ELISA based on microtiter plates. Colorimetric ELISA was the least sensitive, especially at high titer dilutions. The fiber-optic immunosensor based on the same ELISA immunological rationale was the most sensitive technique.

Dilution Confusion: Conventions for Defining a Dilution

ERIC Educational Resources Information Center

Fishel, Laurence A.

2010-01-01

Two conventions for preparing dilutions are used in clinical laboratories. The first convention defines an "a:b" dilution as "a" volumes of solution A plus "b" volumes of solution B. The second convention defines an "a:b" dilution as "a" volumes of solution A diluted into a final volume of "b". Use of the incorrect dilution convention could affect…

Flux Analysis of Free Amino Sugars and Amino Acids in Soils by Isotope Tracing with a Novel Liquid Chromatography/High Resolution Mass Spectrometry Platform

PubMed Central

2017-01-01

Soil fluxomics analysis can provide pivotal information for understanding soil biochemical pathways and their regulation, but direct measurement methods are rare. Here, we describe an approach to measure soil extracellular metabolite (amino sugar and amino acid) concentrations and fluxes based on a 15N isotope pool dilution technique via liquid chromatography and high-resolution mass spectrometry. We produced commercially unavailable 15N and 13C labeled amino sugars and amino acids by hydrolyzing peptidoglycan isolated from isotopically labeled bacterial biomass and used them as tracers (15N) and internal standards (13C). High-resolution (Orbitrap Exactive) MS with a resolution of 50 000 allowed us to separate different stable isotope labeled analogues across a large range of metabolites. The utilization of 13C internal standards greatly improved the accuracy and reliability of absolute quantification. We successfully applied this method to two types of soils and quantified the extracellular gross fluxes of 2 amino sugars, 18 amino acids, and 4 amino acid enantiomers. Compared to the influx and efflux rates of most amino acids, similar ones were found for glucosamine, indicating that this amino sugar is released through peptidoglycan and chitin decomposition and serves as an important nitrogen source for soil microorganisms. d-Alanine and d-glutamic acid derived from peptidoglycan decomposition exhibited similar turnover rates as their l-enantiomers. This novel approach offers new strategies to advance our understanding of the production and transformation pathways of soil organic N metabolites, including the unknown contributions of peptidoglycan and chitin decomposition to soil organic N cycling. PMID:28776982

Manure incorporation reduces environmental nitrogen loss while sustaining crop productivity in the subtropical wheat-maize rotation system: A comprehensive study of nitrogen cycling and balance

NASA Astrophysics Data System (ADS)

Zhou, Minghua; Zhu, Bo; Butterbach-Bahl, klaus; Brüggemann, Nicolas

2016-04-01

Balancing nitrogen (N) budgets of agricultural systems is essential for sustaining yields at lower environmental costs. The knowledge, however, of total N budgets of agricultural systems including all N fluxes is still rare in the literature. Here, we applied a combination of monitoring in situ N fluxes and field 15N tracer and 15N isotope dilution techniques to investigate the effects of different N fertilizers (control, synthetic fertilizer, 60% synthetic fertilizer N plus 40% pig manure N, pig manure only applied at the same N rate 280 kg N ha-1 yr-1) on N pools, cycling processes, fluxes and total N balances in a subtropical wheat-maize rotation system of China. Nitrate leaching and NH3 volatilization were main hydrological and gaseous N loss pathways, respectively. The warm and wet maize season was associated with significantly larger environmental N losses than the cooler and drier wheat season. The field 15N tracing experiment showed that the wheat system had high N retention capacity (˜50% of 15N application) but with short residence time. I.e. 90% of soil residual 15N labelled fertilizer in the wheat system were utilized by plants or lost to the environment in the subsequent maize season. Our annual total N balances of the different treatments revealed that combined synthetic and organic fertilization or manure only maintained the same level of yields and led to significantly lower N losses and higher N retention, even though larger NH3 volatilization losses were caused by manure incorporation. Thus, our study suggests that a combination of synthetic and organic N fertilizers is suitable for sustaining agricultural productivity while reducing environmental N losses through fostering interactions between the soil C and N cycle.

Vibrational spectroscopy of water at interfaces

PubMed Central

Skinner, J. L.; Pieniazek, P. A.; Gruenbaum, S. M.

2011-01-01

Conspectus Recent experimental advances in vibrational spectroscopy, such as ultrafast pulses and heterodyne detection, have made it possible to probe the structure and dynamics of bulk and interfacial water in unprecedented detail. We consider three aqueous interfaces: the water liquid/vapor interface, the interface between water and the surfactant headgroups of reverse micelles, and the interface between water and the lipid headgroups of aligned multi-bilayers. In the first case, sum-frequency spectroscopy is used to probe the interface, while in the second and third cases, the confined water pools are sufficiently small that techniques of bulk spectroscopy such as FTIR, pump-probe, 2DIR, etc. can be used to probe the interfacial water. In this review, we discuss our attempts to model these three systems and interpret the existing experiments. In particular, for the water liquid/vapor interface we find that three-body interactions are essential for reproducing the experimental sum-frequency spectrum, and presumably for the structure of the interface as well. The observed spectrum is interpreted as arising from overlapping and cancelling positive and negative contributions from molecules in different hydrogen-bonding environments. For the reverse micelles, our theoretical models confirm that the experimentally observed blue shift of the water OD stretch (for dilute HOD in H2O) arises from weaker hydrogen bonding to sulfonate oxygens. We interpret the observed slow-down in water rotational dynamics as arising from curvature-induced frustration. For the water confined between lipid bilayers, our theoretical models confirm that the experimentally observed red shift of the water OD stretch arises from stronger hydrogen bonding to phosphate oxygens. We develop a model for heterogeneous vibrational lifetime distributions, and implement the model to calculate isotropic and anisotropic pump-probe decays, and compare with experiment. PMID:22032305

Process and reactor design for biophotolytic hydrogen production.

PubMed

Tamburic, Bojan; Dechatiwongse, Pongsathorn; Zemichael, Fessehaye W; Maitland, Geoffrey C; Hellgardt, Klaus

2013-07-14

The green alga Chlamydomonas reinhardtii has the ability to produce molecular hydrogen (H2), a clean and renewable fuel, through the biophotolysis of water under sulphur-deprived anaerobic conditions. The aim of this study was to advance the development of a practical and scalable biophotolytic H2 production process. Experiments were carried out using a purpose-built flat-plate photobioreactor, designed to facilitate green algal H2 production at the laboratory scale and equipped with a membrane-inlet mass spectrometry system to accurately measure H2 production rates in real time. The nutrient control method of sulphur deprivation was used to achieve spontaneous H2 production following algal growth. Sulphur dilution and sulphur feed techniques were used to extend algal lifetime in order to increase the duration of H2 production. The sulphur dilution technique proved effective at encouraging cyclic H2 production, resulting in alternating Chlamydomonas reinhardtii recovery and H2 production stages. The sulphur feed technique enabled photobioreactor operation in chemostat mode, resulting in a small improvement in H2 production duration. A conceptual design for a large-scale photobioreactor was proposed based on these experimental results. This photobioreactor has the capacity to enable continuous and economical H2 and biomass production using green algae. The success of these complementary approaches demonstrate that engineering advances can lead to improvements in the scalability and affordability of biophotolytic H2 production, giving increased confidence that H2 can fulfil its potential as a sustainable fuel of the future.

Synaptic control of the shape of the motoneuron pool input-output function

PubMed Central

Heckman, Charles J.

2017-01-01

Although motoneurons have often been considered to be fairly linear transducers of synaptic input, recent evidence suggests that strong persistent inward currents (PICs) in motoneurons allow neuromodulatory and inhibitory synaptic inputs to induce large nonlinearities in the relation between the level of excitatory input and motor output. To try to estimate the possible extent of this nonlinearity, we developed a pool of model motoneurons designed to replicate the characteristics of motoneuron input-output properties measured in medial gastrocnemius motoneurons in the decerebrate cat with voltage-clamp and current-clamp techniques. We drove the model pool with a range of synaptic inputs consisting of various mixtures of excitation, inhibition, and neuromodulation. We then looked at the relation between excitatory drive and total pool output. Our results revealed that the PICs not only enhance gain but also induce a strong nonlinearity in the relation between the average firing rate of the motoneuron pool and the level of excitatory input. The relation between the total simulated force output and input was somewhat more linear because of higher force outputs in later-recruited units. We also found that the nonlinearity can be increased by increasing neuromodulatory input and/or balanced inhibitory input and minimized by a reciprocal, push-pull pattern of inhibition. We consider the possibility that a flexible input-output function may allow motor output to be tuned to match the widely varying demands of the normal motor repertoire. NEW & NOTEWORTHY Motoneuron activity is generally considered to reflect the level of excitatory drive. However, the activation of voltage-dependent intrinsic conductances can distort the relation between excitatory drive and the total output of a pool of motoneurons. Using a pool of realistic motoneuron models, we show that pool output can be a highly nonlinear function of synaptic input but linearity can be achieved through adjusting the time course of excitatory and inhibitory synaptic inputs. PMID:28053245

High-Resolution Fibre-Optic Temperature Sensing: A New Tool to Study the Two-Dimensional Structure of Atmospheric Surface-Layer Flow

NASA Astrophysics Data System (ADS)

Thomas, Christoph K.; Kennedy, Adam M.; Selker, John S.; Moretti, Ayla; Schroth, Martin H.; Smoot, Alexander R.; Tufillaro, Nicholas B.; Zeeman, Matthias J.

2012-02-01

We present a novel approach based on fibre-optic distributed temperature sensing (DTS) to measure the two-dimensional thermal structure of the surface layer at high resolution (0.25 m, ≈0.5 Hz). Air temperature observations obtained from a vertically-oriented fibre-optics array of approximate dimensions 8 m × 8 m and sonic anemometer data from two levels were collected over a short grass field located in the flat bottom of a wide valley with moderate surface heterogeneity. The objectives of the study were to evaluate the potential of the DTS technique to study small-scale processes in the surface layer over a wide range of atmospheric stability, and to analyze the space-time dynamics of transient cold-air pools in the calm boundary layer. The time response and precision of the fibre-based temperatures were adequate to resolve individual sub-metre sized turbulent and non-turbulent structures, of time scales of seconds, in the convective, neutral, and stable surface layer. Meaningful sensible heat fluxes were computed using the eddy-covariance technique when combined with vertical wind observations. We present a framework that determines the optimal environmental conditions for applying the fibre-optics technique in the surface layer and identifies areas for potentially significant improvements of the DTS performance. The top of the transient cold-air pool was highly non-stationary indicating a superposition of perturbations of different time and length scales. Vertical eddy scales in the strongly stratified transient cold-air pool derived from the DTS data agreed well with the buoyancy length scale computed using the vertical velocity variance and the Brunt-Vaisala frequency, while scales for weak stratification disagreed. The high-resolution DTS technique opens a new window into spatially sampling geophysical fluid flows including turbulent energy exchange.

Long-Term Controls on Solute and Sediment Fluxes From a Rapidly Weathering Tropical Watershed

NASA Astrophysics Data System (ADS)

Shanley, J. B.; McDowell, W. H.; Stallard, R. F.

2006-12-01

The 326-ha Rio Icacos watershed in the tropical wet forest of the Luquillo Mountains, northeastern Puerto Rico, is underlain by granodiorite bedrock with weathering rates among the highest in the world. We pooled stream chemistry and suspended sediment datasets from three discrete periods: 1983-87; 1991-97; and 2000-05, which bracket two major hurricanes that crossed the site; Hugo in 1988 and Georges in 1998. This mountainous landscape is also subject to frequent disturbance by landslides. Stream major ion chemistry reflects weathering of the granodiorite, but dilutes by as much as 90% during the largest storms. This dilution reflects the increasing dominance of rainwater (and cloud water) with increasing streamflow, as major ion stoichiometry is maintained except when precipitation is high in sea salt. Given the broad area of surface saturation, low-permeability soils, and flashy stream hydrograph which quickly returns to base flow, it appears that precipitation moves to the stream by saturation overland flow. Piping and rapid shallow subsurface flow through the rooting zone may also facilitate precipitation movement off hillslopes. Concentration-discharge relations for most major ions were fairly stable through time, suggesting minimal long-term effects from disturbance. The exception was nitrate, which increased from near 5 μmol L-1 during the 1983-87 period to greater than 12 μmol L-1 and remaining elevated for several years following each of the two hurricanes. The relation between suspended sediment concentration and discharge was also stable over time but exhibited more variability, some due to hysteresis but some likely caused by pulsed sediment from discrete disturbances.

Laboratory heterogeneity of the lupus anticoagulant: a multicentre study using different clotting assays on a panel of 78 samples. Hemostasis Committee of the "Société Française de Biologie Clinique".

PubMed

1992-05-15

The laboratory heterogeneity of the lupus anticoagulant (LA) was investigated in a multicentre study using a panel of 78 plasma samples diagnosed as containing a LA. Consecutive samples were collected by 12 participants using various screening tests, and sent to 7 laboratories which performed one or more clotting assays among the following: activated partial thromboplastin time (APTT), dilute Russell viper venom time, kaolin clotting time (KCT), dilute tissue thromboplastin time (dTTI) and a platelet neutralization test. For APTT and dTTI, 10 versions of these tests including standard and mixing procedures were carried out. They varied by reagents, phospholipid concentration or methodology. Cut-off times were determined for each test by comparing the results of the panel to those of a control population. When the data of all clotting assays were pooled, 70 of the 78 selected plasmas were considered to contain LA, 15 of them having a low-titer inhibitor. Sensitivity, defined as the proportion of positive results among LA-containing plasmas, varied from 62 to 100% and was positively related to responsiveness (defined as the mean ratio of clotting time to cut-off time). Laboratory heterogeneity of LA-containing plasma was illustrated by a star symbol plot analysis. Different populations of samples, with LA preferentially recognized by one assay (or group of assays) irrespective of the overall sensitivity of this assay, were identified. Multiple component analysis demonstrated the heterogeneity of low-titer inhibitors, which complicates their recognition in routine laboratory investigation.

L-carnitine is a survival factor for chilled storage of rooster semen for a long time.

PubMed

Fattah, A; Sharafi, M; Masoudi, R; Shahverdi, A; Esmaeili, V

2017-02-01

Rooster sperm is sensitive to cooling, which restricts procedures to store sperms for extended periods of time for artificial insemination of commercial flocks. This study was conducted to evaluate the suitability of adding L-carnitine (LC) to chilled-storage of rooster sperm and its effects on sperm quality parameters and its fertility potential during storage at 5 °C. Pooled semen from roosters were divided into six equal aliquots and diluted with media supplemented with different concentrations of LC (0, 0.5, 1, 2, 4 and 8 mM LC). Diluted semen samples were cooled to 5 °C and stored over 48 h. Motility, viability, membrane functionality, lipid peroxidation and mitochondria activity of the sperm were assessed at 0, 24 and 48 h of storage. Moreover, fertility potential of chilled stored sperm was considered at 24 h of storage. While sperm quality was not affected by LC at the beginning of storage (0 h), supplementation of extender with 1 and 2 mM of LC significantly improved the percentage of sperm motility, viability, membrane integrity and mitochondria activity at 24 h and 48 h compared to other groups. Lipid peroxidation was significantly reduced in sperm samples diluted with 1 and 2 mM LC at 24 h (2.15 ± 0.52 nmol/ml and 2.21 ± 0.52 nmol/ml) and 48 h (3.42 ± 0.49 nmol/ml and 3.38 ± 0.49 nmol/ml) compared to other groups. Furthermore, fertility rates during artificial insemination using sperms cooled for 24 h in the presence of 1 and 2 mM LC were significantly higher (78%) than in the control group (64%). These findings suggest that optimum doses of LC could protect rooster sperm against cool storage-induced functional and structural damages. Copyright © 2016 Elsevier Inc. All rights reserved.

Factors Influencing Divergent Patterns of Phosphorus Availability in NY and PA Biogeochemical `Hotspots'

NASA Astrophysics Data System (ADS)

Saia, S. M.; Hofmeister, K.; Regan, J. M.; Buda, A. R.; Carrick, H. J.; Walter, M. T.

2016-12-01

Anthropogenic alteration of the soil phosphorus (P) cycle leads to subsequent water quality issues in agricultural dominated watersheds. In the humid Northeastern United States (NE US), variably saturated areas can generate surface runoff that transports P and stimulates biogeochemical processes; these hydrologically dynamic locations are often called biogeochemical `hotspots'. Many studies have evaluated nitrogen and carbon cycling in biogeochemical hot spots but few have focused on P. We hypothesized seasonally wet parts of the landscape (i.e., hotspots) have smaller biologically available P pools because runoff events frequently carry away nutrients like P. To test this hypothesis, we generated soil wetness index (SWI) maps from soil (SURRGO) and elevation (LiDAR rescaled to 3 m) data and used these maps to direct seasonal soil sampling near Klingerstown, Pennsylvania (PA) and Ithaca, New York (NY). We collected 5cm deep soil samples in PA (bimonthly) and NY (monthly) along soil moisture gradients for a range of land cover types (forest, fallow, and cropped) from May through October. We measured soil moisture in the field and percent organic matter (OM), pH, and three increasingly strong soil P extractions (dilute-salt-extractable P, oxalate-extractable P, and total-extractable P) in the laboratory. Our results indicated a negative relationship between dilute-salt-extractable P concentrations and SWI in PA and no relationship between these same variables in NY. We also found positive relationships between each of the three P extractions in PA but only a positive relationship between oxalate-extractable P and total-extractable P in NY. Our findings in PA support our hypothesis; namely, less biologically available P (i.e. dilute-salt-extractable P) is found in wetter areas of the landscape. However, divergent P availability patterns in NY point to further complexities and confounding variables in our understanding in soil P processes. Further studies will look into the importance of environmental variables such as OM and pH on P patterns under changing soil moisture regimes. The knowledge gained from this study will improve our understanding of P cycling in biogeochemical hotspots and can be used to improve the effectiveness of agricultural management practices in the NE US.

Heat Transfer in Boiling Dilute Emulsion with Strong Buoyancy

NASA Astrophysics Data System (ADS)

Freeburg, Eric Thomas

Little attention has been given to the boiling of emulsions compared to that of boiling in pure liquids. The advantages of using emulsions as a heat transfer agent were first discovered in the 1970s and several interesting features have since been studied by few researchers. Early research focuses primarily on pool and flow boiling and looks to determine a mechanism by which the boiling process occurs. This thesis looks at the boiling of dilute emulsions in fluids with strong buoyant forces. The boiling of dilute emulsions presents many favorable characteristics that make it an ideal agent for heat transfer. High heat flux electronics, such as those seen in avionics equipment, produce high heat fluxes of 100 W/cm2 or more, but must be maintained at low temperatures. So far, research on single phase convection and flow boiling in small diameter channels have yet to provide an adequate solution. Emulsions allow the engineer to tailor the solution to the specific problem. The fluid can be customized to retain the high thermal conductivity and specific heat capacity of the continuous phase while enhancing the heat transfer coefficient through boiling of the dispersed phase component. Heat transfer experiments were carried out with FC-72 in water emulsions. FC-72 has a saturation temperature of 56 °C, far below that of water. The parameters were varied as follows: 0% ≤ epsilon ≤ 1% and 1.82 x 1012 ≤ RaH ≤ 4.42 x 1012. Surface temperatures along the heated surface reached temperature that were 20 °C in excess of the dispersed phase saturation temperature. An increase of ˜20% was seen in the average Nusselt numbers at the highest Rayleigh numbers. Holography was used to obtain images of individual and multiple FC-72 droplets in the boundary layer next to the heated surface. The droplet diameters ranged from 0.5 mm to 1.3 mm. The Magnus effect was observed when larger individual droplets were injected into the boundary layer, causing the droplets to be pushed outside the boundary layer. Vaporization of FC-72 droplets in the boundary layer next to the heated surface was not observed.

Hydrogeochemical effects of a bulkhead in the Dinero mine tunnel, Sugar Loaf mining district, near Leadville, Colorado

USGS Publications Warehouse

Walton-Day, Katherine; Mills, Taylor J.

2015-01-01

The Dinero mine drainage tunnel is an abandoned, draining mine adit near Leadville, Colorado, that has an adverse effect on downstream water quality and aquatic life. In 2009, a bulkhead was constructed (creating a mine pool and increasing water-table elevations behind the tunnel) to limit drainage from the tunnel and improve downstream water quality. The goal of this study was to document changes to hydrology and water quality resulting from bulkhead emplacement, and to understand post-bulkhead changes in source water and geochemical processes that control mine-tunnel discharge and water quality. Comparison of pre-and post-bulkhead hydrology and water quality indicated that tunnel discharge and zinc and manganese loads decreased by up to 97 percent at the portal of Dinero tunnel and at two downstream sites (LF-537 and LF-580). However, some water-quality problems persisted at LF-537 and LF-580 during high-flow events and years, indicating the effects of the remaining mine waste in the area. In contrast, post-bulkhead water quality degraded at three upstream stream sites and a draining mine tunnel (Nelson tunnel). Water-quality degradation in the streams likely occurred from increased contributions of mine-pool groundwater to the streams. In contrast, water-quality degradation in the Nelson tunnel was likely from flow of mine-pool water along a vein that connects the Nelson tunnel to mine workings behind the Dinero tunnel bulkhead. Principal components analysis, mixing analysis, and inverse geochemical modeling using PHREEQC indicated that mixing and geochemical reactions (carbonate dissolution during acid weathering, precipitation of goethite and birnessite, and sorption of zinc) between three end-member water types generally explain the pre-and post-bulkhead water composition at the Dinero and Nelson tunnels. The three end members were (1) a relatively dilute groundwater having low sulfate and trace element concentrations; (2) mine pool water, and (3) water that flowed from a structure in front of the bulkhead after bulkhead emplacement. Both (2) and (3) had high sulfate and trace element concentrations. These results indicate how analysis of monitoring information can be used to understand hydrogeochemical changes resulting from bulkhead emplacement. This understanding, in turn, can help inform future decisions on the disposition of the remaining mine waste and water-quality problems in the area.

Determination of gamma-aminobutyric acid in food matrices by isotope dilution hydrophilic interaction chromatography coupled to mass spectrometry.

PubMed

Zazzeroni, Raniero; Homan, Andrew; Thain, Emma

2009-08-01

The estimation of the dietary intake of gamma-aminobutyric acid (GABA) is dependent upon the knowledge of its concentration values in food matrices. To this end, an isotope dilution liquid chromatography-mass spectrometry method has been developed employing the hydrophilic interaction chromatography technique for analyte separation. This approach enabled accurate quantification of GABA in apple, potato, soybeans, and orange juice without the need of a pre- or post-column derivatization reaction. A selective and precise analytical measurement has been obtained with a triple quadrupole mass spectrometer operating in multiple reaction monitoring using the method of standard additions and GABA-d(6) as an internal standard. The concentrations of GABA found in the matrices tested are 7 microg/g of apple, 342 microg/g of potatoes, 211 microg/g of soybeans, and 344 microg/mL of orange juice.

Effect of diluted and preheated oxidizer on the emission of methane flameless combustion

NASA Astrophysics Data System (ADS)

Hosseini, Seyed Ehsan; Salehirad, Saber; Wahid, M. A.; Sies, Mohsin Mohd; Saat, Aminuddin

2012-06-01

In combustion process, reduction of emissions often accompanies with output efficiency reduction. It means, by using current combustion technique it is difficult to obtainlow pollution and high level of efficiency in the same time. In new combustion system, low NOxengines and burners are studied particularly. Recently flameless or Moderate and Intensive Low oxygen Dilution (MILD) combustion has received special attention in terms of low harmful emissions and low energy consumption. Behavior of combustion with highly preheated air was analyzed to study the change of combustion regime and the reason for the compatibility of high performance and low NOx production. Sustainability of combustion under low oxygen concentration was examined when; the combustion air temperature was above the self-ignition temperature of the fuel. This paper purposes to analyze the NOx emission quantity in conventional combustion and flameless combustion by Chemical Equilibrium with Applications (CEA) software.

Isolation and structural characterization of sugarcane bagasse lignin after dilute phosphoric acid plus steam explosion pretreatment and its effect on cellulose hydrolysis.

PubMed

Zeng, Jijiao; Tong, Zhaohui; Wang, Letian; Zhu, J Y; Ingram, Lonnie

2014-02-01

The structure of lignin after dilute phosphoric acid plus steam explosion pretreatment process of sugarcane bagasse in a pilot scale and the effect of the lignin extracted by ethanol on subsequent cellulose hydrolysis were investigated. The lignin structural changes caused by pretreatment were identified using advanced nondestructive techniques such as gel permeation chromatography (GPC), quantitative (13)C, and 2-D nuclear magnetic resonance (NMR). The structural analysis revealed that ethanol extractable lignin preserved basic lignin structure, but had relatively lower amount of β-O-4 linkages, syringyl/guaiacyl units ratio (S/G), p-coumarate/ferulate ratio, and other ending structures. The results also indicated that approximately 8% of mass weight was extracted by pure ethanol. The bagasse after ethanol extraction had an approximate 22% higher glucose yield after enzyme hydrolysis compared to pretreated bagasse without extraction. Copyright © 2013 Elsevier Ltd. All rights reserved.

Standardized methods and quality control limits for agar and broth microdilution susceptibility testing of Mycoplasma pneumoniae, Mycoplasma hominis, and Ureaplasma urealyticum.

PubMed

Waites, Ken B; Duffy, Lynn B; Bébéar, Cécile M; Matlow, Anne; Talkington, Deborah F; Kenny, George E; Totten, Patricia A; Bade, Donald J; Zheng, Xiaotian; Davidson, Maureen K; Shortridge, Virginia D; Watts, Jeffrey L; Brown, Steven D

2012-11-01

An international multilaboratory collaborative study was conducted to develop standard media and consensus methods for the performance and quality control of antimicrobial susceptibility testing of Mycoplasma pneumoniae, Mycoplasma hominis, and Ureaplasma urealyticum using broth microdilution and agar dilution techniques. A reference strain from the American Type Culture Collection was designated for each species, which was to be used for quality control purposes. Repeat testing of replicate samples of each reference strain by participating laboratories utilizing both methods and different lots of media enabled a 3- to 4-dilution MIC range to be established for drugs in several different classes, including tetracyclines, macrolides, ketolides, lincosamides, and fluoroquinolones. This represents the first multilaboratory collaboration to standardize susceptibility testing methods and to designate quality control parameters to ensure accurate and reliable assay results for mycoplasmas and ureaplasmas that infect humans.

System and technique for ultrasonic characterization of settling suspensions

DOEpatents

Greenwood, Margaret S [Richland, WA; Panetta, Paul D [Richland, WA; Bamberger, Judith A [Richland, WA; Pappas, Richard A [Richland, WA

2006-11-28

A system for determining properties of settling suspensions includes a settling container, a mixer, and devices for ultrasonic interrogation transverse to the settling direction. A computer system controls operation of the mixer and the interrogation devices and records the response to the interrogating as a function of settling time, which is then used to determine suspension properties. Attenuation versus settling time for dilute suspensions, such as dilute wood pulp suspension, exhibits a peak at different settling times for suspensions having different properties, and the location of this peak is used as one mechanism for characterizing suspensions. Alternatively or in addition, a plurality of ultrasound receivers are arranged at different angles to a common transmitter to receive scattering responses at a variety of angles during particle settling. Angular differences in scattering as a function of settling time are also used to characterize the suspension.

An investigation into the effects of excipient particle size, blending techniques and processing parameters on the homogeneity and content uniformity of a blend containing low-dose model drug

PubMed Central

Alyami, Hamad; Dahmash, Eman; Bowen, James

2017-01-01

Powder blend homogeneity is a critical attribute in formulation development of low dose and potent active pharmaceutical ingredients (API) yet a complex process with multiple contributing factors. Excipient characteristics play key role in efficient blending process and final product quality. In this work the effect of excipient type and properties, blending technique and processing time on content uniformity was investigated. Powder characteristics for three commonly used excipients (starch, pregelatinised starch and microcrystalline cellulose) were initially explored using laser diffraction particle size analyser, angle of repose for flowability, followed by thorough evaluations of surface topography employing scanning electron microscopy and interferometry. Blend homogeneity was evaluated based on content uniformity analysis of the model API, ergocalciferol, using a validated analytical technique. Flowability of powders were directly related to particle size and shape, while surface topography results revealed the relationship between surface roughness and ability of excipient with high surface roughness to lodge fine API particles within surface groves resulting in superior uniformity of content. Of the two blending techniques, geometric blending confirmed the ability to produce homogeneous blends at low dilution when processed for longer durations, whereas manual ordered blending failed to achieve compendial requirement for content uniformity despite mixing for 32 minutes. Employing the novel dry powder hybrid mixer device, developed at Aston University laboratory, results revealed the superiority of the device and enabled the production of homogenous blend irrespective of excipient type and particle size. Lower dilutions of the API (1% and 0.5% w/w) were examined using non-sieved excipients and the dry powder hybrid mixing device enabled the development of successful blends within compendial requirements and low relative standard deviation. PMID:28609454

Blood volume analysis: a new technique and new clinical interest reinvigorate a classic study.

PubMed

Manzone, Timothy A; Dam, Hung Q; Soltis, Daniel; Sagar, Vidya V

2007-06-01

Blood volume studies using the indicator dilution technique and radioactive tracers have been performed in nuclear medicine departments for over 50 y. A nuclear medicine study is the gold standard for blood volume measurement, but the classic dual-isotope blood volume study is time-consuming and can be prone to technical errors. Moreover, a lack of normal values and a rubric for interpretation made volume status measurement of limited interest to most clinicians other than some hematologists. A new semiautomated system for blood volume analysis is now available and provides highly accurate results for blood volume analysis within only 90 min. The availability of rapid, accurate blood volume analysis has brought about a surge of clinical interest in using blood volume data for clinical management. Blood volume analysis, long a low-volume nuclear medicine study all but abandoned in some laboratories, is poised to enter the clinical mainstream. This article will first present the fundamental principles of fluid balance and the clinical means of volume status assessment. We will then review the indicator dilution technique and how it is used in nuclear medicine blood volume studies. We will present an overview of the new semiautomated blood volume analysis technique, showing how the study is done, how it works, what results are provided, and how those results are interpreted. Finally, we will look at some of the emerging areas in which data from blood volume analysis can improve patient care. The reader will gain an understanding of the principles underlying blood volume assessment, know how current nuclear medicine blood volume analysis studies are performed, and appreciate their potential clinical impact.

An investigation into the effects of excipient particle size, blending techniques and processing parameters on the homogeneity and content uniformity of a blend containing low-dose model drug.

PubMed

Alyami, Hamad; Dahmash, Eman; Bowen, James; Mohammed, Afzal R

2017-01-01

Powder blend homogeneity is a critical attribute in formulation development of low dose and potent active pharmaceutical ingredients (API) yet a complex process with multiple contributing factors. Excipient characteristics play key role in efficient blending process and final product quality. In this work the effect of excipient type and properties, blending technique and processing time on content uniformity was investigated. Powder characteristics for three commonly used excipients (starch, pregelatinised starch and microcrystalline cellulose) were initially explored using laser diffraction particle size analyser, angle of repose for flowability, followed by thorough evaluations of surface topography employing scanning electron microscopy and interferometry. Blend homogeneity was evaluated based on content uniformity analysis of the model API, ergocalciferol, using a validated analytical technique. Flowability of powders were directly related to particle size and shape, while surface topography results revealed the relationship between surface roughness and ability of excipient with high surface roughness to lodge fine API particles within surface groves resulting in superior uniformity of content. Of the two blending techniques, geometric blending confirmed the ability to produce homogeneous blends at low dilution when processed for longer durations, whereas manual ordered blending failed to achieve compendial requirement for content uniformity despite mixing for 32 minutes. Employing the novel dry powder hybrid mixer device, developed at Aston University laboratory, results revealed the superiority of the device and enabled the production of homogenous blend irrespective of excipient type and particle size. Lower dilutions of the API (1% and 0.5% w/w) were examined using non-sieved excipients and the dry powder hybrid mixing device enabled the development of successful blends within compendial requirements and low relative standard deviation.

Nanoshell assisted laser soldering of vascular tissue.

PubMed

Schöni, Daniel S; Bogni, Serge; Bregy, Amadé; Wirth, Amina; Raabe, Andreas; Vajtai, Istvan; Pieles, Uwe; Reinert, Michael; Frenz, Martin

2011-12-01

Laser tissue soldering (LTS) is a promising technique for tissue fusion but is limited by the lack of reproducibility particularly when the amount of indocyanine green (ICG) applied as energy absorber cannot be controlled during the soldering procedure. Nanotechnology enables the control over the quantitative binding of the ICG. The aim of this study was to establish a highly reproducible and strong tissue fusion using ICG packed nanoshells. By including the chromophore in the soldering scaffold, dilution of the energy absorber during the soldering procedure is prevented. The feasibility of this novel nanoshell soldering technique was studied by assessing the local heating of the area and tensile strength of the resulting fused tissue. Nanoshells with a diameter of 250-270 nm were loaded with ICG and included in a porous polycaprolactone (PCL) scaffold doped with albumin solder. The nanoshell scaffold was used in a flexible, semi-dry formulation suitable for surgical use. Heat development, tensile strength as well as tissue damage were assessed. Rabbit aortic arteries were successfully soldered using an ICG packed nanoshell scaffold. Tensile strengths of these nanoshell soldered anastomoses were found to be 734 ± 327 mN (median = 640 mN). Thermal damage was restricted to the adventitia at the irradiated area. In addition, absorber dilution was prevented during the soldering procedure resulting in significantly lower variance in maximum temperature (P = 0.03) compared to the classical liquid ICG soldering technique. Using nanoshells, controlled amounts of chromophore could successfully be bound into the polymer scaffold. Diode laser soldering of vascular tissue using ICG-nanoshell scaffolds leads to strong and reproducible tissue fusion. With optimally chosen settings of irradiation time, nanoshells coating and scaffold properties, our improved LTS procedure demonstrates the potential for a clinically applicable anastomosis technique. Copyright © 2011 Wiley Periodicals, Inc.

Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. II. Formation and decomposition of thiosulfate and polythionate in Cinder Pool

USGS Publications Warehouse

Xu, Y.; Schoonen, M.A.A.; Nordstrom, D. Kirk; Cunningham, K.M.; Ball, J.W.

2000-01-01

Cinder Pool is an acid-sulfate-chloride boiling spring in Norris Geyser Basin, Yellowstone National Park. The pool is unique in that its surface is partially covered with mm-size, black, hollow sulfur spherules, while a layer of molten sulfur resides at the bottom of the pool (18 m depth). The sulfur speciation in the pool was determined on four different days over a period of two years. Samples were taken to evaluate changes with depth and to evaluate the importance of the sulfur spherules on sulfur redox chemistry. All analyses were conducted on site using a combination of ion chromatography and colorimetric techniques. Dissolved sulfide (H2S), thiosulfate (S2O32−), polythionates (SxO62−), and sulfate were detected. The polythionate concentration was highly variable in time and space. The highest concentrations were found in surficial samples taken from among the sulfur spherules. With depth, the polythionate concentrations dropped off. The maximum observed polythionate concentration was 8 μM. Thiosulfate was rather uniformly distributed throughout the pool and concentrations ranged from 35 to 45 μM. Total dissolved sulfide concentrations varied with time, concentrations ranged from 16 to 48 μM. Sulfate was relatively constant, with concentrations ranging from 1150 to 1300 μM. The sulfur speciation of Cinder Pool is unique in that the thiosulfate and polythionate concentrations are significantly higher than for any other acid-sulfate spring yet sampled in Yellowstone National Park. Complementary laboratory experiments show that thiosulfate is the intermediate sulfoxyanion formed from sulfur hydrolysis under conditions similar to those found in Cinder Pool and that polythionates are formed via the oxidation of thiosulfate by dissolved oxygen. This last reaction is catalyzed by pyrite that occurs as a minor constituent in the sulfur spherules floating on the pool's surface. Polythionate decomposition proceeds via two pathways: (1) a reaction with H2S, yielding thiosulfate and elemental sulfur; and (2) by disproportionation to sulfate and thiosulfate. This study demonstrates that the presence of a subaqueous molten sulfur pool and sulfur spherules in Cinder Pool is of importance in controlling the pathways of aqueous sulfur redox reactions. Some of the insights gained at Cinder Pool may be relevant to acid crater lakes where sulfur spherules are observed and variations in polythionate concentrations are used to monitor and predict volcanic activity.

Discrete Fractional Component Monte Carlo Simulation Study of Dilute Nonionic Surfactants at the Air-Water Interface.

PubMed

Yoo, Brian; Marin-Rimoldi, Eliseo; Mullen, Ryan Gotchy; Jusufi, Arben; Maginn, Edward J

2017-09-26

We present a newly developed Monte Carlo scheme to predict bulk surfactant concentrations and surface tensions at the air-water interface for various surfactant interfacial coverages. Since the concentration regimes of these systems of interest are typically very dilute (≪10 -5 mol. frac.), Monte Carlo simulations with the use of insertion/deletion moves can provide the ability to overcome finite system size limitations that often prohibit the use of modern molecular simulation techniques. In performing these simulations, we use the discrete fractional component Monte Carlo (DFCMC) method in the Gibbs ensemble framework, which allows us to separate the bulk and air-water interface into two separate boxes and efficiently swap tetraethylene glycol surfactants C 10 E 4 between boxes. Combining this move with preferential translations, volume biased insertions, and Wang-Landau biasing vastly enhances sampling and helps overcome the classical "insertion problem", often encountered in non-lattice Monte Carlo simulations. We demonstrate that this methodology is both consistent with the original molecular thermodynamic theory (MTT) of Blankschtein and co-workers, as well as their recently modified theory (MD/MTT), which incorporates the results of surfactant infinite dilution transfer free energies and surface tension calculations obtained from molecular dynamics simulations.

Delivery of Formulated Industrial Enzymes with Acoustic Technology.

PubMed

Hwang, Jennifer Dorcas; Ortiz-Maldonado, Mariliz; Paramonov, Sergey

2016-02-01

Industrial enzymes are instrumental in many applications, including carbohydrate processing, fabric and household care, biofuels, food, and animal nutrition, among others. Enzymes have to be active and stable not only in harsh application conditions, but also during shipment and storage. In protein stability studies, formulated concentrated enzyme solutions are frequently diluted gravimetrically prior to enzyme activity measurements, making it challenging to move toward more high-throughput techniques using conventional robotic equipment. Current assay methods pose difficulties when measuring highly concentrated proteins. For example, plastic pipette tips can introduce error because proteins adsorb to the tip surface, despite the presence of detergents, decreasing precision and overall efficiency of protein activity assays. Acoustic liquid handling technology, frequently used for various dilute small-molecule assays, may overcome such problems. Originally shown to effectively deliver dilute solutions of small molecules, this technology is used here as an effective alternative to the aforementioned challenge with viscous concentrated protein solutions. Because the acoustic liquid handler transfers nanoliter quantities of liquids without using pipette tips and without sample loss, it rapidly and uniformly prepares assay plates for enzyme activity measurements within minutes. This increased efficiency transforms the nature of enzyme stability studies toward high precision and throughput. © 2015 Society for Laboratory Automation and Screening.

One-step refolding and purification of recombinant human tumor necrosis factor-α (rhTNF-α) using ion-exchange chromatography.

PubMed

Wang, Yan; Ren, Wenxuan; Gao, Dong; Wang, Lili; Yang, Ying; Bai, Quan

2015-02-01

Protein refolding is a key step for the production of recombinant proteins, especially at large scales, and usually their yields are very low. Chromatographic-based protein refolding techniques have proven to be superior to conventional dilution refolding methods. High refolding yield can be achieved using these methods compared with dilution refolding of proteins. In this work, recombinant human tumor necrosis factor-α (rhTNF-α) from inclusion bodies expressed in Escherichia coli was renatured with simultaneous purification by ion exchange chromatography with a DEAE Sepharose FF column. Several chromatographic parameters influencing the refolding yield of the denatured/reduced rhTNF-α, such as the urea concentration, pH value and concentration ratio of glutathione/oxidized glutathione in the mobile phase, were investigated in detail. Under optimal conditions, rhTNF-α can be renatured and purified simultaneously within 30 min by one step. Specific bioactivity of 2.18 × 10(8) IU/mg, purity of 95.2% and mass recovery of 76.8% of refolded rhTNF-α were achieved. Compared with the usual dilution method, the ion exchange chromatography method developed here is simple and more effective for rhTNF-α refolding in terms of specific bioactivity and mass recovery. Copyright © 2014 John Wiley & Sons, Ltd.

Highly sensitive and selective hyphenated technique (molecularly imprinted polymer solid-phase microextraction-molecularly imprinted polymer sensor) for ultra trace analysis of aspartic acid enantiomers.

PubMed

Prasad, Bhim Bali; Srivastava, Amrita; Tiwari, Mahavir Prasad

2013-03-29

The present work is related to combination of molecularly imprinted solid-phase microextraction and complementary molecularly imprinted polymer-sensor. The molecularly imprinted polymer grafted on titanium dioxide modified silica fiber was used for microextraction, while the same polymer immobilized on multiwalled carbon nanotubes/titanium dioxide modified pencil graphite electrode served as a detection tool. In both cases, the surface initiated polymerization was found to be advantageous to obtain a nanometer thin imprinted film. The modified silica fiber exhibited high adsorption capacity and enantioselective diffusion of aspartic acid isomers into respective molecular cavities. This combination enabled double preconcentrations of d- and l-aspartic acid that helped sensing both isomers in real samples, without any cross-selectivity and matrix complications. Taking into account 6×10(4)-fold dilution of serum and 2×10(3)-fold dilution of cerebrospinal fluid required by the proposed method, the limit of detection for l-aspartic acid is 0.031ngmL(-1). Also, taking into account 50-fold dilution required by the proposed method, the limit of detection for d-aspartic acid is 0.031ngmL(-1) in cerebrospinal fluid. Copyright © 2013 Elsevier B.V. All rights reserved.

Micro-scale extensional rheometry using hyperbolic converging/diverging channels and jet breakup

PubMed Central

Keshavarz, Bavand

2016-01-01

Understanding the elongational rheology of dilute polymer solutions plays an important role in many biological and industrial applications ranging from microfluidic lab-on-a-chip diagnostics to phenomena such as fuel atomization and combustion. Making quantitative measurements of the extensional viscosity for dilute viscoelastic fluids is a long-standing challenge and it motivates developments in microfluidic fabrication techniques and high speed/strobe imaging of millifluidic capillary phenomena in order to develop new classes of instruments. In this paper, we study the elongational rheology of a family of dilute polymeric solutions in two devices: first, steady pressure-driven flow through a hyperbolic microfluidic contraction/expansion and, second, the capillary driven breakup of a thin filament formed from a small diameter jet (Dj∼O(100 μm)). The small length scale of the device allows very large deformation rates to be achieved. Our results show that in certain limits of low viscosity and elasticity, jet breakup studies offer significant advantages over the hyperbolic channel measurements despite the more complex implementation. Using our results, together with scaling estimates of the competing viscous, elastic, inertial and capillary timescales that control the dynamics, we construct a dimensionless map or nomogram summarizing the operating space for each instrument. PMID:27375824

Identification of Ginger (Zingiber officinale Roscoe) Volatiles and Localization of Aroma-Active Constituents by GC-Olfactometry.

PubMed

Pang, Xueli; Cao, Jianmin; Wang, Dabin; Qiu, Jun; Kong, Fanyu

2017-05-24

For the characterization of chemical components contributing to the aroma of ginger, which could benefit the development of deep-processed ginger products, volatile extracts were isolated by a combination of direct solvent extraction-solvent-assisted flavor evaporation and static headspace analysis. Aroma-impact components were identified by gas chromatography-olfactometry-mass spectrometry, and the most potent odorants were further screened by aroma extract dilution analysis (AEDA) and static headspace dilution analysis (SHDA). The AEDA results revealed that geranial, eucalyptol, β-linalool, and bornyl acetate were the most potent odorants, exhibiting the highest flavor dilution factor (FD factor) of 2187. SHDA indicated that the predominant headspace odorants were α-pinene and eucalyptol. In addition, odorants exhibiting a high FD factor in SHDA were estimated to be potent aroma contributors in AEDA. The predominant odorants were found to be monoterpenes and sesquiterpenes, as along with their oxygenated derivatives, providing minty, lemon-like, herbal, and woody aromas. On the other hand, three highly volatile compounds detected by SHDA were not detected by AEDA, whereas 34 high-polarity, low-volatility compounds were identified only by AEDA, demonstrating the complementary natures of SHDA and AEDA and the necessity of utilizing both techniques to accurately characterize the aroma of ginger.

[Effects of invasive Cenchrus spinifex on nitrogen pools in sandy grassland].

PubMed

Zhang, Ting; Fu, Wei Dong; Zhang, Rui Hai; Song, Zhen; Bai, Chao; Huang, Cheng Cheng; Zhang, Guo Liang

2017-05-18

Cenchrus spinifex is an invasive plant found in large areas of northern China. In this study, we focused on analysis of the effects of C. spinifex on soil nitrogen and plant nitrogen pools in Horqin sandy grassland. In addition, a pot experiment with 15 N tracing techniques was designed to study the biological nitrogen fixation ability of C. spinifex, compared with two native grasses, Elymus dahuricus and Agropyron cristatum. The total soil nitrogen pool in C. spinifex invaded-area increased significantly by 47.5% and 20.8%, and the soil ammonium nitrogen pool decreased significantly by 25.6% and 25.2%, compared with those in bare and native plant Roegneria kamoji areas, respectively. The plant shoot nitrogen pool decreased significantly by 18.7% in C. spinifex compared with native plant R. kamoji. Atom% 15 N, atom% 15 N excess and atom% 15 N weighting excess of C. spinifex were all significantly lower than those of E. dahuricus and A. cristatum. The nitrogen use efficiencies of C. spinifex and E. dahuricus were 48.5% and 47.0%, respectively, and no significant difference was observed. Ndfa of C. spinifex accounted for 60.2%, when growing together with E. dahuricus. These results suggested that the characteristics on the high efficient use for nitrogen of this invasive weed might an ecological adaptation mechanism, leading to successful colonization and spread in Horqin Steppe.

Chemical, Thermal and Spectroscopic Methods to Assess Biodegradation of Winery-Distillery Wastes during Composting.

PubMed

Torres-Climent, A; Gomis, P; Martín-Mata, J; Bustamante, M A; Marhuenda-Egea, F C; Pérez-Murcia, M D; Pérez-Espinosa, A; Paredes, C; Moral, R

2015-01-01

The objective of this work was to study the co-composting process of wastes from the winery and distillery industry with animal manures, using the classical chemical methods traditionally used in composting studies together with advanced instrumental methods (thermal analysis, FT-IR and CPMAS 13C NMR techniques), to evaluate the development of the process and the quality of the end-products obtained. For this, three piles were elaborated by the turning composting system, using as raw materials winery-distillery wastes (grape marc and exhausted grape marc) and animal manures (cattle manure and poultry manure). The classical analytical methods showed a suitable development of the process in all the piles, but these techniques were ineffective to study the humification process during the composting of this type of materials. However, their combination with the advanced instrumental techniques clearly provided more information regarding the turnover of the organic matter pools during the composting process of these materials. Thermal analysis allowed to estimate the degradability of the remaining material and to assess qualitatively the rate of OM stabilization and recalcitrant C in the compost samples, based on the energy required to achieve the same mass losses. FT-IR spectra mainly showed variations between piles and time of sampling in the bands associated to complex organic compounds (mainly at 1420 and 1540 cm-1) and to nitrate and inorganic components (at 875 and 1384 cm-1, respectively), indicating composted material stability and maturity; while CPMAS 13C NMR provided semi-quantitatively partition of C compounds and structures during the process, being especially interesting their variation to evaluate the biotransformation of each C pool, especially in the comparison of recalcitrant C vs labile C pools, such as Alkyl /O-Alkyl ratio.

Chemical, Thermal and Spectroscopic Methods to Assess Biodegradation of Winery-Distillery Wastes during Composting

PubMed Central

Torres-Climent, A.; Gomis, P.; Martín-Mata, J.; Bustamante, M. A.; Marhuenda-Egea, F. C.; Pérez-Murcia, M. D.; Pérez-Espinosa, A.; Paredes, C.; Moral, R.

2015-01-01

The objective of this work was to study the co-composting process of wastes from the winery and distillery industry with animal manures, using the classical chemical methods traditionally used in composting studies together with advanced instrumental methods (thermal analysis, FT-IR and CPMAS 13C NMR techniques), to evaluate the development of the process and the quality of the end-products obtained. For this, three piles were elaborated by the turning composting system, using as raw materials winery-distillery wastes (grape marc and exhausted grape marc) and animal manures (cattle manure and poultry manure). The classical analytical methods showed a suitable development of the process in all the piles, but these techniques were ineffective to study the humification process during the composting of this type of materials. However, their combination with the advanced instrumental techniques clearly provided more information regarding the turnover of the organic matter pools during the composting process of these materials. Thermal analysis allowed to estimate the degradability of the remaining material and to assess qualitatively the rate of OM stabilization and recalcitrant C in the compost samples, based on the energy required to achieve the same mass losses. FT-IR spectra mainly showed variations between piles and time of sampling in the bands associated to complex organic compounds (mainly at 1420 and 1540 cm-1) and to nitrate and inorganic components (at 875 and 1384 cm-1, respectively), indicating composted material stability and maturity; while CPMAS 13C NMR provided semi-quantitatively partition of C compounds and structures during the process, being especially interesting their variation to evaluate the biotransformation of each C pool, especially in the comparison of recalcitrant C vs labile C pools, such as Alkyl /O-Alkyl ratio. PMID:26418458

Temperature Field During Flame Spread over Alcohol Pools: Measurements and Modelling

NASA Technical Reports Server (NTRS)

Miller, Fletcher J.; Ross, Howard D.; Schiller, David N.

1994-01-01

A principal difference between flame spread over solid fuels and over liquid fuels is, in the latter case, the presence of liquid-phase convection ahead of the leading edge of the flame. The details of the fluid dynamics and heat transfer mechanisms in both the pulsating and uniform flame spread regimes were heavily debated, without resolution, in the 1960s and 1970s; recently, research on flame spread over pools was reinvigorated by the advent of enhanced diagnostic techniques and computational power. Temperature fields in the liquid, which enable determination of the extent of preheating ahead of the flame, were determined previously by the use of thermocouples and repetitive tests, and suggested that the surface temperature does not decrease monotonically ahead of the pulsating flame front, but that there exists a surface temperature valley. Recent predictions support this suggestion. However, others' thermocouple measurements and the recent field measurements using Holographic Interferometry (HI) did not find a similar valley. In this work we examine the temperature field using Rainbow Schlieren Deflectometry (RSD), with a measurement threshold exceeding that of conventional interferometry by a factor of 20:1, for uniform and pulsating flame spread using propanol and butanol as fuels. This technique was not applied before to flame spread over liquid pools, except in some preliminary measurements reported earlier. Noting that HI is sensitive to the refractive index while RSD responds to refractive index gradients, and that these two techniques might therefore be difficult to compare, we utilized a numerical simulation, described below, to predict and compare both types of field for the uniform and pulsating spread regimes. The experimental data also allows a validation of the model at a level of detail greater than has been attempted before.