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排序方式: 共有882条查询结果,搜索用时 31 毫秒
91.
Past efforts at curing infection with the human immunodeficiency virus (HIV) have been blocked by the resistance of some infected cells to viral cytopathic effects and the associated development of a latent viral reservoir. Furthermore, current efforts to clear the viral reservoir by means of reactivating latent virus are hampered by the lack of cell death in the newly productively infected cells. The purpose of this review is to describe the many anti-apoptotic mechanisms of HIV, as well as the current limitations in the field. Only by understanding how infected cells avoid HIV-induced cell death can an effective strategy to kill infected cells be developed.  相似文献   
92.
Book reviews     
This paper traces the relationship between the food committees of the Royal Society and government during the First World War, concentrating on the period up to the resignation of Lord Devonport as first Food Controller. It argues that, in the context of a radical public science discourse emanating from some sections of the scientific community and greatly increased contacts between scientists and government, the food scientists of the committees were moved to press for a formalization of the committees' role in food policy. The members constantly manoeuvred to achieve this aim, but also used a network of alternative channels into the heart of the policy process to get their findings translated into hard policy. In doing so, they explicitly rehearsed characteristic 'public science' arguments. In the institutional blur of wartime state-science relations, scientists often got close to the policy-making process. Post-War, the state swiftly moved to clarify the position: science was to be given more money, but was to be specifically blocked by new administrative arrangements embodied in the Haldane Report on the Machinery of Government from having any say in the core areas of general policy, the expert domain of the generalist policy-maker.  相似文献   
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94.
Application of information technology and environmental planning share two very important characteristics: they are both concerned with planning, evaluating, and directing human activity in a wider context, and this activity is multiaspectual, multimodal, and multidisciplinary in scope. Further, the ideal in both cases is sustainable, long-term activity that brings overall good rather than harm. This paper discusses the multiaspectual nature of environmental sustainability and shows briefly how this understanding can be translated to the field of information systems.  相似文献   
95.
96.
Segregation of transferable R factors into Escherichia coli minicells   总被引:18,自引:0,他引:18  
S B Levy  P Norman 《Nature》1970,227(5258):606-607
  相似文献   
97.
Proliferation of human lymphocytes in culture   总被引:9,自引:0,他引:9  
M S Sasaki  A Norman 《Nature》1966,210(5039):913-914
  相似文献   
98.
A refined physical map of chromosome 17q21.31 uncovered a 900-kb inversion polymorphism. Chromosomes with the inverted segment in different orientations represent two distinct lineages, H1 and H2, that have diverged for as much as 3 million years and show no evidence of having recombined. The H2 lineage is rare in Africans, almost absent in East Asians but found at a frequency of 20% in Europeans, in whom the haplotype structure is indicative of a history of positive selection. Here we show that the H2 lineage is undergoing positive selection in the Icelandic population, such that carrier females have more children and have higher recombination rates than noncarriers.  相似文献   
99.
100.
Morgan AD  Gandon S  Buckling A 《Nature》2005,437(7056):253-256
Antagonistic coevolution between hosts and parasites in spatially structured populations can result in local adaptation of parasites; that is, the greater infectivity of local parasites than foreign parasites on local hosts. Such parasite specialization on local hosts has implications for human health and agriculture. By contrast with classic single-species population-genetic models, theory indicates that parasite migration between subpopulations might increase parasite local adaptation, as long as migration does not completely homogenize populations. To test this hypothesis we developed a system-specific mathematical model and then coevolved replicate populations of the bacterium Pseudomonas fluorescens and a parasitic bacteriophage with parasite only, with host only or with no migration. Here we show that patterns of local adaptation have considerable temporal and spatial variation and that, in the absence of migration, parasites tend to be locally maladapted. However, in accord with our model, parasite migration results in parasite local adaptation, but host migration alone has no significant effect.  相似文献   
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