Compositing Water Samples for Analysis of Volatile Organic Compounds

Accurate mean concentrations of volatile organic compounds (VOCs) can easily and economically be obtained from a single VOC analysis by using proven methods of collecting representative, discrete water samples and compositing them with a gas-tight syringe. The technique can be used in conjunction with chemical analysis by a conventional laboratory, field-portable equipment, or a mobile laboratory. The type of mean concentration desired depends on the objectives of monitoring. For example, flow-weighted mean VOC concentrations can be used to estimate mass loadings in wastewater and urban storm water, and spatially integrated mean VOC concentrations can be used to assess sources of drinking water (e.g., reservoirs and rivers). The mean error in a discrete sample due to compositing is about 2% for most VOC concentrations greater than 0.1 μg∕L. The total error depends on the number of discrete samples comprising the composite sample and precision of the chemical analysis.     

MPP+ induced substantia nigra degeneration is attenuated in nNOS knockout mice

Differential scanning calorimetry was used to characterize thermal events associated with freezing and melting of suspensions and extracts of Panagrolaimus davidi, an Antarctic nematode which can survive intracellular freezing. Nematode suspensions produced a single freezing exotherm with a shoulder on the peak representing the freezing of the nematodes. A shoulder on the peak of melting endotherms indicates the melting of the nematodes and of the water surrounding them. Exotherms were also detected from individual nematodes mounted in liquid paraffin. The freezing of nematodes was very rapid and in marked contrast to that of freezing-tolerant insects and vertebrates, which take hours or days to freeze. Eighty-two percent of the nematodes' body water froze. High levels of survival were obtained in nematodes exposed to temperatures down to -40 degrees C. No additional thermal events were observed after the freezing event and before the melting of samples cooled to -40 degrees C, indicating no changes in the proportion of body water frozen. Ice nucleating activity is present in nematode suspensions but not in supernatants from nematode extracts. No thermal hysteresis activity was detected in nematode extracts.     

Comparing transmission potential networks based on social network surveys,close contacts and environmental overlap in rural Madagascar

Social and spatial network analysis is an important approach for investigating infectious disease transmission, especially for pathogens transmitted directly between individuals or via environmental reservoirs. Given the diversity of ways to construct networks, however, it remains unclear how well networks constructed from different data types effectively capture transmission potential. We used empirical networks from a population in rural Madagascar to compare social network survey and spatial data-based networks of the same individuals. Close contact and environmental pathogen transmission pathways were modelled with the spatial data. We found that naming social partners during the surveys predicted higher close-contact rates and the proportion of environmental overlap on the spatial data-based networks. The spatial networks captured many strong and weak connections that were missed using social network surveys alone. Across networks, we found weak correlations among centrality measures (a proxy for superspreading potential). We conclude that social network surveys provide important scaffolding for understanding disease transmission pathways but miss contact-specific heterogeneities revealed by spatial data. Our analyses also highlight that the superspreading potential of individuals may vary across transmission modes. We provide detailed methods to construct networks for close-contact transmission pathogens when not all individuals simultaneously wear GPS trackers.     

Treatment level progress and time spent in treatment in the prediction of outcomes following drug-free therapeutic community treatment

Previous research has suggested that time spent in treatment is the most important predictor of therapeutic community treatment outcomes. Although level divisions or treatment stages represent the basic structure for segmenting responsibility and authority within traditional therapeutic communities, the relationship of this treatment component to treatment outcome has not previously been investigated. AIM: To test the hypothesis that higher treatment level attainment, more time spent in treatment and additional time spent within a treatment level has a linear association with improvements at outcome. DESIGN: Retrospective quasi-experimental. PARTICIPANTS: Four hundred and twenty-seven ex-residents, stratified according to their highest level of treatment in the Melbourne Odyssey House therapeutic community between 1984 and 1988 were targeted for follow-up and 60% were successfully located and interviewed an average of 5.6 years after their first Odyssey entry. Analysis of official records of methadone treatment, convictions and incarcerations demonstrated no post-treatment differences comparing those interviewed with those not interviewed. MEASUREMENTS: Drug use, criminal involvement and employment. FINDINGS. Although both level attainment and time spent in treatment had a linear relationship to improved outcomes, level attainment was a better predictor of outcomes at treatment exit. An unexpected finding was that those who had spent the median time or longer in particular levels demonstrated worse outcomes on official conviction records and on self-reports of employment compared to those remaining for less than the median time. CONCLUSION: The results suggest that it may be level progress rather than simply time spent in treatment that best explains improved functioning following exit from the therapeutic community.     

The world's first automobile fatality

The first recorded automobile fatality occurred in a small town in the Irish Midlands in 1869. Mary Ward, a celebrated microscopist, artist, astronomer and naturalist, fell from a steam carriage and died after crush injuries from its heavy iron wheels. The story of first automobile fatality characterizes the individual tragedy that is each premature death. It also illuminates the story of a remarkable Victorian scientific family. Among their many achievements was the building of a reflector telescope in the heart of rural Ireland that was the largest in the world for 74 years.     

A review of studies on the mode of action of clofibrate and betabenzalbutyrate

Clofibrate and betabenzalbutyrate produce a variety of metabolic alterations in vivo. These include reduction in serum triglyceride and alterations in adipose tissue uptake and release of lipids. Clofibrate displaces thyroxine from albumin binding sites and produces an enlargement of liver and changes in ultrastructure. The biochemical changes produced by clofibrate include reduction in adenyl cyclase activity, inhibition of acetyl CoA carboxylase, inhibition of cholesterol biosynthesis and inhibition of triglyceride formation. Recent studies in this laboratory have shown that the inhibition of hepatic triglyceride formation is an early metabolic consequence of clofibrate administration and precedes the fall in serum triglyceride and several of the other biochemical alterations. Moreover clofibrate and betabenzalbutyrate inhibit the esterification ofsn-glycerol-3-P by rat liver homogenate and microsomal preparations. The initial step in this pathway, acyl-CoA-sn-glycerol-3-P acyltransferase, is inhibited by both drugs, in vitro. It is possible that this in vitro inhibition explains the early hypotriglyceridemic effect of these agents. One of eight papers presented at the symposium “Recent Advances in Drugs Affecting Lipid Metabolism,” AOCS Meeting, Houston, May 1971.     

Sorbic acid containing triglycerides in aphids and their fractionation by high pressure liquid chromatography

The sorbic acid containing triglycerides found in various aphid species have been fractionated by high pressure liquid chromatography. Mass spectral analysis afforded identification of three isolates as 2-trans, trans-sorbo-1, 3 dimyristin; 2-trans, trans-sorbo-1,3 myristopalmitin; and 2-trans, trans-sorbo-1,3 dipalmitin. No evidence of asymmetry was found by circular dichroism. The composition and proportions of these triglycerides was found to be species variable.