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641.
E. S. Burt Hamilton 《BMJ (Clinical research ed.)》1921,2(3179):968-969
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Michael P. Hughes Hywel Morgan Frazer J. Rixon Julian P.H. Burt Ronald Pethig 《Biochimica et Biophysica Acta (BBA)/General Subjects》1998,1425(1):119-126
The frequency-dependent dielectrophoretic behaviour of an enveloped mammalian virus, herpes simplex virus type 1 is described. It is demonstrated that over the range 10 kHz–20 MHz, these viral particles, when suspended in an aqueous medium of conductivity 5 mS m?1, can be manipulated by both positive and negative dielectrophoresis using microfabricated electrode arrays. The observed transition from positive to negative dielectrophoresis at frequencies around 4.5 MHz is in qualitative agreement with a simple model of the virus as a conducting particle surrounded by an insulating membrane. 相似文献
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GABAA receptors are GABA (gamma-aminobutyric acid)-gated chloride channels, which are major mediators of neuronal inhibition in the brain and are modulated by benzodiazepines, barbiturates, alcohol, and other important centrally acting drugs. Although previous pharmacological and biochemical data had suggested a degree of heterogeneity, recent cloning of at least 15 different receptor subunits, thought to be combined in groups of five, indicates that the brain may contain a truly astonishing variety of GABAA receptor subtypes. This review describes the little that is known about these subtypes, emphasizing possible molecular bases of receptor heterogeneity. We also discuss approaches to establishing the subunit composition of subtypes. 相似文献
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Are artificial reefs surrogates of natural habitats for corals and fish in Dubai,United Arab Emirates? 总被引:1,自引:0,他引:1
Artificial reefs are often promoted as mitigating human impacts in coastal ecosystems and enhancing fisheries; however, evidence
supporting their benefits is equivocal. Such structures must be compared with natural reefs in order to assess their performance,
but past comparisons typically examined artificial structures that were too small, or were immature, relative to the natural
reefs. We compared coral and fish communities on two large (>400,000 m3) and mature (>25 year) artificial reefs with six natural coral patches. Coral cover was higher on artificial reefs (50%)
than in natural habitats (31%), but natural coral patches contained higher species richness (29 vs. 20) and coral diversity
(H′ = 2.3 vs. 1.8). Multivariate analyses indicated strong differences between coral communities in natural and artificial habitats.
Fish communities were sampled seasonally for 1 year. Multivariate fish communities differed significantly among habitat types
in the summer and fall, but converged in the winter and spring. Univariate analysis indicated that species richness and abundance
were stable throughout the year on natural coral patches but increased significantly in the summer on artificial reefs compared
with the winter and spring, explaining the multivariate changes in community structure. The increased summer abundance on
artificial reefs was mainly due to adult immigration. Piscivores were much more abundant in the fall than in the winter or
spring on artificial reefs, but had low and stable abundance throughout the year in natural habitats. It is likely that the
decreased winter and spring abundance of fish on the artificial reefs resulted from both predation and emigration. These results
indicate that large artificial reefs can support diverse and abundant coral and fish communities. However, these communities
differ structurally and functionally from those in natural habitats, and they should not be considered as replacements for
natural coral and fish communities. 相似文献
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