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71.
72.
Johnson D. L. J. Hager A. Hunt D. A. Griffith S. Blount S. Ellsworth J. Hintz R. Lucci A. Mittiga D. Prokhorova L. Tidd M. M. Millones M. Vincent 《中国科学C辑(英文版)》2005,48(1):92
A program of house dust sample collection and analysis has begun in Syracuse, New York, USA, in order to determine the feasibility of a geography-based exposure assessment for urban metals. The sampling program, and the protocols it employs, is described for two different types of wipe media, Ghost Wipes and Whatman Filters. Preliminary results show that strong spatial patterns of floor dust loading (mg dust per square foot) can be observed for data aggregated at a spatial scale of about 1600 m (~2.5 km2). Floor dust metal concentrations were similar to those found in other urban environments, with some regional variation. The median floor dust Pb concentration was ~108 mg · kg?1 for this initial data set of ~264 sampled residential locations, and varied from 50 to 1100 mg Pb · kg?1. 相似文献
73.
The changes in lipid peroxidation, antioxidative and lignifying enzyme activities were studied in leaves and stems of Cu-stressed
sunflower seedlings. In both organs, membrane lipid peroxidation was enhanced by copper treatment. Additionally, catalase
(EC 1.11.1.6) and superoxide dismutase (EC 1.15.1.1) activities were modulated: The activity of superoxide dismutase was enhanced
in both plant organs. Differently, catalase activity was not affected in leaves but significantly reduced in stems. Peroxidase
(EC 1.11.1.7) activities were also changed. Guaiacol peroxidase activity was increased in leaves and stems. In the same way,
electrophoretic analysis of the anionic isoperoxidases involved in lignification (syringaldazine peroxidase) revealed qualitative
and quantitative changes on the isoenzyme patterns. These modifications were accompanied by the increase of the NADH-oxidase
activity in ionically cell wall bound fraction. It appeared that the growth delay caused by copper excess could be related
to the activation of lignifying peroxidases. 相似文献
74.
Use of mass spectrometry, capillary electrophoresis, and gel electrophoresis for quality analysis of synthetic oligonucleotides: Perspectives from the ABRF nucleic acid research group 下载免费PDF全文
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Stephan Francke Karine Clement Christian Dina Hiroshi Inoue Philip Behn Vincent Vatin Arnaud Basdevant Bernard Guy-Grand M. Alan Permutt Philippe Froguel J. Hager 《Human genetics》1997,100(5-6):491-496
Family studies have shown that in some populations up to 75% of the variation of body mass index can be explained by genetic
factors. However, in humans, no major obesity gene has been identified to date. In contrast, there are a number of genetically
well defined animal models for obesity. In two of those models (ob/ob and db/db), defects in the same pathway are responsible
for obesity. Recently, some evidence has been found for the OB gene also being involved in human obesity. In this study we
investigated the potential role of the OB receptor (OBR) in the etiology of massive obesity in humans using familial linkage
analyses and case-control association studies. The typing of two microsatellite markers (D1S198 and D1S209), flanking the
OBR gene, in 256 sib pairs showed no evidence for linkage with obesity. In order to be able to detect small gene effects,
association studies with a 3′-UTR insertion/deletion polymorphism were carried out. The results of these analyses remained
non-significant (χ2 = 3.442, P = 0.18). However, subjects heterozygous for the insertion/deletion polymorphism showed a slight trend towards lower insulin
values 30 min after an oral glucose load compared to homozygous individuals (P = 0.02). In summary, our results do not support a major role of the human OBR gene in the development of morbid obesity in
our population.
Received: 4 December 1996 / Accepted: 25 June 1997 相似文献
78.
Fatty acid chlorohydrins are characterized as lipid components of an edible jellyfish. The four isomers 9-chloro-10-hydroxypalmitic acid, 10-chloro-9-hydroxypalmitic acid, 9-chloro-10-hydroxystearic acid, and 10-chloro-9-hydroxystearic acid were identified by gas chromatography-mass spectrometry comparison of the methyl esters and their trimethylsilyl derivatives with known synthetic samples. Two additional isomers, 11-chloro-12-hydroxystearic acid and 12-chloro-11-hydroxystearic acid, were also found in the lipid by the identification of the expected mass spectral fragments of the trimethylsilyl (Me3Si) derivative of their methyl esters. These six isomeric compounds represented approximately 1.4% of the total extractable jellyfish lipid and were released from the lipid as methyl esters by boron trifluoride-methanol treatment. These isomers account for only about 30% of the organic chlorine in the lipid. Evidence is given that the remaining organic chlorine is also present as fatty acid chlorohydrins containing more than one hydroxyl group. 相似文献
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Thirty borderline essential hypertensives were randomly assigned to a portable constant-cuff blood pressure feedback technique or meditation-relaxation. Each technique was taught in the laboratory, then practiced twice daily at home for four weeks. Subjects mailed daily records of their progress. Seven feedback and ten meditation-relaxation subjects completed the program. Both techniques produced significant systolic and diastolic reductions within practice sessions and diastolic reductions over weeks of training. Neither technique improved reductions nor reduced initial systolic pressure levels over the four weeks. Differences between biofeedback and meditation-relaxation in within-session pressure reductions were not significant. 相似文献