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121.
122.
Retinal resistance barriers and electrical lateral inhibition. 总被引:6,自引:0,他引:6
123.
Global and societal implications of the diabetes epidemic. 总被引:111,自引:0,他引:111
Changes in human behaviour and lifestyle over the last century have resulted in a dramatic increase in the incidence of diabetes worldwide. The epidemic is chiefly of type 2 diabetes and also the associated conditions known as 'diabesity' and 'metabolic syndrome'. In conjunction with genetic susceptibility, particularly in certain ethnic groups, type 2 diabetes is brought on by environmental and behavioural factors such as a sedentary lifestyle, overly rich nutrition and obesity. The prevention of diabetes and control of its micro- and macrovascular complications will require an integrated, international approach if we are to see significant reduction in the huge premature morbidity and mortality it causes. 相似文献
124.
湿地状态对石油污染和植物长势影响的模拟研究 总被引:2,自引:0,他引:2
模拟实验中建立了一系列不同状态的“湿地桶”,桶中装有从黄河三角洲采集的被石油污染的土壤和当地的湿地植物。通过监测湿地植物(芦苇、香蒲等)的长势和化验土壤中总石油烃(TPH)及油和脂(O/G)随时间的变化,以探讨湿地状态对石油污染和植物长势的影响。结果显示:湿地环境对土壤中的石油污染有明显的降解作用,芦苇等挺水植物的生长量与积水深度呈正相关,土壤中少量含油并不构成对湿地植物生长的威胁。此实验可为建立油田的湿地缓冲带提供科学依据。 相似文献
125.
Antibiotic bioassay by flow microcalorimetry 总被引:1,自引:0,他引:1
A. E. Beezer R. J. Miles Elizabeth J. Shaw Lynne Vickerstaff 《Cellular and molecular life sciences : CMLS》1980,36(9):1051-1052
Summary A rapid, sensitive microcalorimetric bioassay of good reproducibility has been developed for the antibiotics penicillin-G, carbenicillin, ampicillin and cefoxitin. The use of growing organisms as responding agents allows discussion of the results for systems which may involve biological fluids.Acknowledgment. We thank the Department of Health and Social Security for a grant to support this work. 相似文献
126.
A human immunoglobulin gene reduces the incidence of lymphomas in c-Myc-bearing transgenic mice 总被引:13,自引:0,他引:13
M C Nussenzweig E V Schmidt A C Shaw E Sinn J Campos-Torres B Mathey-Prevot P K Pattengale P Leder 《Nature》1988,336(6198):446-450
Transgenic mice carrying an immunoglobulin enhancer-driven c-myc oncogene develop rapid-onset pre-B cell lymphomas. The incidence of these malignancies is greatly reduced when an additional transgene encoding the membrane-bound form (but not the secreted form) of human Ig mu is bred into the susceptible strain. This suppressive effect correlates with a subtle alteration in B-cell development induced by the immunoglobulin transgene. 相似文献
127.
Rock-magnetic and palaeomagnetic studies have been carried out on the interval of famous fossil-bearing sedimentary rocks and its overlying basalts and underlying basalts at the Sihetun section, West Liaoning Province. Normal polarity was obtained for the sedimentary interval and the underlying basalts, while reversed polarity was found in the overlying basalts. Taking account of the new40Ar/39Ar ages (Swisher et al., 1999), we classified the fossil-bearing sedimentary interval into the Barremian M3n zone (Early Cretaceous age). Several abnormal horizons on magnetic properties, probably corresponding to the tuffs, were observed in the fossil-bearing sedimentary interval. This implies that the massive bio-extinction may link to dramatic environmental changes that were caused by volcanic eruptions. 相似文献
128.
Recent spending cuts in the area of adult social care raise policy concerns about the proportion of older people whose need for social care is not being met. Such concerns are emphasised in the context of population ageing and other demographic changes. For example, the increasing proportion of the population aged 75 and over places greater pressure on formal and informal systems of care and support provision, while changes in the living arrangements of older people may affect the supply of informal care within the household. This article explores the concept of 'unmet need' for support in relation to specific Activities of Daily Living (ADLs) and Instrumental Activities of Daily Living (IADLs), using data on the receipt of support (informal, formal state or formal paid) from the General Household Survey, the English Longitudinal Study of Ageing and the British Household Panel Survey. The results show that different kinds of need tend to be supported by particular sources of care, and that there is a significant level of 'unmet need' for certain activities. 相似文献
129.
Mutations in the human ortholog of Aristaless cause X-linked mental retardation and epilepsy 总被引:20,自引:0,他引:20
Strømme P Mangelsdorf ME Shaw MA Lower KM Lewis SM Bruyere H Lütcherath V Gedeon AK Wallace RH Scheffer IE Turner G Partington M Frints SG Fryns JP Sutherland GR Mulley JC Gécz J 《Nature genetics》2002,30(4):441-445
Mental retardation and epilepsy often occur together. They are both heterogeneous conditions with acquired and genetic causes. Where causes are primarily genetic, major advances have been made in unraveling their molecular basis. The human X chromosome alone is estimated to harbor more than 100 genes that, when mutated, cause mental retardation. At least eight autosomal genes involved in idiopathic epilepsy have been identified, and many more have been implicated in conditions where epilepsy is a feature. We have identified mutations in an X chromosome-linked, Aristaless-related, homeobox gene (ARX), in nine families with mental retardation (syndromic and nonspecific), various forms of epilepsy, including infantile spasms and myoclonic seizures, and dystonia. Two recurrent mutations, present in seven families, result in expansion of polyalanine tracts of the ARX protein. These probably cause protein aggregation, similar to other polyalanine and polyglutamine disorders. In addition, we have identified a missense mutation within the ARX homeodomain and a truncation mutation. Thus, it would seem that mutation of ARX is a major contributor to X-linked mental retardation and epilepsy. 相似文献
130.
Genome divergence in two Prochlorococcus ecotypes reflects oceanic niche differentiation 总被引:1,自引:0,他引:1
Rocap G Larimer FW Lamerdin J Malfatti S Chain P Ahlgren NA Arellano A Coleman M Hauser L Hess WR Johnson ZI Land M Lindell D Post AF Regala W Shah M Shaw SL Steglich C Sullivan MB Ting CS Tolonen A Webb EA Zinser ER Chisholm SW 《Nature》2003,424(6952):1042-1047
The marine unicellular cyanobacterium Prochlorococcus is the smallest-known oxygen-evolving autotroph. It numerically dominates the phytoplankton in the tropical and subtropical oceans, and is responsible for a significant fraction of global photosynthesis. Here we compare the genomes of two Prochlorococcus strains that span the largest evolutionary distance within the Prochlorococcus lineage and that have different minimum, maximum and optimal light intensities for growth. The high-light-adapted ecotype has the smallest genome (1,657,990 base pairs, 1,716 genes) of any known oxygenic phototroph, whereas the genome of its low-light-adapted counterpart is significantly larger, at 2,410,873 base pairs (2,275 genes). The comparative architectures of these two strains reveal dynamic genomes that are constantly changing in response to myriad selection pressures. Although the two strains have 1,350 genes in common, a significant number are not shared, and these have been differentially retained from the common ancestor, or acquired through duplication or lateral transfer. Some of these genes have obvious roles in determining the relative fitness of the ecotypes in response to key environmental variables, and hence in regulating their distribution and abundance in the oceans. 相似文献