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排序方式: 共有126条查询结果,搜索用时 31 毫秒
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Due to taxonomic positions and special living environments, marine organisms produce secondary metabolites that possess unique structures and biological activities. This review is devoted to recently isolated and/or earlier described marine compounds with potential or established cancer preventive activities, their biological sources, molecular mechanisms of their action, and their associations with human health and nutrition. The review covers literature published in 2003–2013 years and focuses on findings of the last 2 years. 相似文献
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Ortega Jaime Díaz Sedov Sergey Romero Francisco Jardines Luis Gerardo Martínez Rebolledo Elizabeth Solleiro 《Journal of Soils and Sediments》2022,22(3):942-956
Journal of Soils and Sediments - The objective of this study was to examine the pedogenetic evolution occurring in technic hard materials from an iron mine through the characterization of a... 相似文献
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Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of the organophosphorus pesticide parathion-methyl 总被引:11,自引:0,他引:11
Kolosova AY Park JH Eremin SA Kang SJ Chung DH 《Journal of agricultural and food chemistry》2003,51(5):1107-1114
A fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the detection of parathion-methyl (PM) was developed and optimized. Fluorescein-labeled PM derivatives (tracers) with different structures were synthesized and purified by thin-layer chromatography. The influence of immunogen and tracer structures on the assay characteristics was investigated. PM concentration determinable by the FPIA ranged from 25 to 10000 ppb. The detection limit was 15 ppb. Methanol extracts of vegetable, fruit, and soil samples were diluted 1/10 for the analysis. Recovery in spiked samples averaged between 85 and 110%. The method developed is characterized by high specificity and reproducibility (CV ranged from 1.5 to 9.1% for interassay and from 1.8 to 14.1% for intra-assay). The FPIA method can be applied to the screening of food and environmental samples for PM residues without complicated cleanup. 相似文献
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Feinberg AW Feigel A Shevkoplyas SS Sheehy S Whitesides GM Parker KK 《Science (New York, N.Y.)》2007,317(5843):1366-1370
We demonstrate the assembly of biohybrid materials from engineered tissues and synthetic polymer thin films. The constructs were built by culturing neonatal rat ventricular cardiomyocytes on polydimethylsiloxane thin films micropatterned with extracellular matrix proteins to promote spatially ordered, two-dimensional myogenesis. The constructs, termed muscular thin films, adopted functional, three-dimensional conformations when released from a thermally sensitive polymer substrate and were designed to perform biomimetic tasks by varying tissue architecture, thin-film shape, and electrical-pacing protocol. These centimeter-scale constructs perform functions as diverse as gripping, pumping, walking, and swimming with fine spatial and temporal control and generating specific forces as high as 4 millinewtons per square millimeter. 相似文献
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Davis S Begon M De Bruyn L Ageyev VS Klassovskiy NL Pole SB Viljugrein H Stenseth NC Leirs H 《Science (New York, N.Y.)》2004,304(5671):736-738
In Kazakhstan and elsewhere in central Asia, the bacterium Yersinia pestis circulates in natural populations of gerbils, which are the source of human cases of bubonic plague. Our analysis of field data collected between 1955 and 1996 shows that plague invades, fades out, and reinvades in response to fluctuations in the abundance of its main reservoir host, the great gerbil (Rhombomys opimus). This is a rare empirical example of the two types of abundance thresholds for infectious disease-invasion and persistence- operating in a single wildlife population. We parameterized predictive models that should reduce the costs of plague surveillance in central Asia and thereby encourage its continuance. 相似文献
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A MicroRNA feedback circuit in midbrain dopamine neurons 总被引:4,自引:0,他引:4
Kim J Inoue K Ishii J Vanti WB Voronov SV Murchison E Hannon G Abeliovich A 《Science (New York, N.Y.)》2007,317(5842):1220-1224
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Characterization of mammalian selenoproteomes 总被引:3,自引:0,他引:3
Kryukov GV Castellano S Novoselov SV Lobanov AV Zehtab O Guigó R Gladyshev VN 《Science (New York, N.Y.)》2003,300(5624):1439-1443
In the genetic code, UGA serves as a stop signal and a selenocysteine codon, but no computational methods for identifying its coding function are available. Consequently, most selenoprotein genes are misannotated. We identified selenoprotein genes in sequenced mammalian genomes by methods that rely on identification of selenocysteine insertion RNA structures, the coding potential of UGA codons, and the presence of cysteine-containing homologs. The human selenoproteome consists of 25 selenoproteins. 相似文献
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When females can reproduce without males, do males become an evolutionarily weaker sex whose genes experience mutational decay? We addressed this hypothesis in aphids, whose reproduction alternates between parthenogenetic and sexual forms: Over the course of a year, there can be 10 to 20 generations of asexual females but only a single, if any, generation with males. We used microarray analyses to identify male-biased, asexual female-biased, and neutral genes. Interspecific comparisons reveal accelerated evolution of male-biased genes, and intraspecific polymorphisms exhibit a significant excess of nonsynonymous coding variation in male-biased genes. We conclude that the ability of females to reproduce asexually without males reduces selection constraints on male-based genes, resulting in their mutational decay. 相似文献