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71.
GA Bray 《Obesity (Silver Spring, Md.)》1997,5(3):271-274
It is often difficult to identify the ‘who, when, and where’ of advances in medicine and surgery because it's a rare advance indeed (such as the use of digitalis by William Withering) that can be clearly related to the astuteness of one person at one time and place. 相似文献
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SÉBASTIEN VILLÉGER GAËL GRENOUILLET VIRGINIE SUC SÉBASTIEN BROSSE 《Freshwater Biology》2012,57(11):2330-2341
1. We measured N and P excretion rates of 470 individuals belonging to 18 freshwater fish species widespread in Western Europe. We assessed the effect of body mass on excretion rates at both the intra‐ and interspecific levels. 2. The high variability in per capita N and P excretion rates was mainly determined by differences in body mass. The scaling coefficients of allometric relationships for both N and P excretion rates were significantly lower than 1 (mean ± SE, 0.95 ± 0.04 and 0.81 ± 0.05, respectively). 3. The slope of the allometric relationship between fish mass and nutrient excretion rate was significantly different among species. We did not detect any influence of phylogenetic conservatism on fish mass and on excretion rates. Further investigations are needed to understand the biological determinants of these differences. 4. This high intra‐ and interspecific variability in per capita excretion rates, coupled with differences in fish body mass, produce marked differences in biomass‐standardised excretion rates. These results thus indicate the necessity for further experimental and in situ investigations on the consequences of nutrient recycling by fish in freshwater ecosystems. 相似文献
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目的比较腺嘌呤诱导与氢化可的松诱导的SD大鼠肾阳虚模型的优劣,从而得到临床症状、生化指标更符合中医“肾阳虚”型的动物模型,以供科研、教学使用。方法雄性SD大鼠100只,随机分成正常组、腺嘌呤造模组及氢化可的松低剂量组、中剂量组、高剂量组各20只,造模成功后检测血肌酐(Scr)、尿素氮(BUN)、尿液中17-羟皮质类固醇(17-OH)和血浆中甲状腺激素(13、T4)、睾丸酮(T)、雌二醇(E2)及模型大鼠骨密度。结果无论从症状主证方面,还是客观指标方面(除骨密度外),腺嘌呤诱导的SD大鼠肾阳虚型动物模型在生化指标研究方面均优于氢化可的松诱导组。结论腺嘌呤诱导的肾阳虚证SD大鼠模型在症状主证方面及其相关的生化研究方面优于氢化可的松组。 相似文献
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Variability in responses to thermal stress in parasitoids 总被引:1,自引:0,他引:1
GAËLLE AMICE PHILIPPE VERNON YANNICK OUTREMAN JACQUES VAN ALPHEN JOAN VAN BAAREN 《Ecological Entomology》2008,33(6):701-708
Abstract 1. To study phenotypic effects of stress, a stress is applied to cohorts of organisms with an increasing intensity. In the absence of mortality the response of traits will be a decreasing function of stress intensity because of increasing physiological costs. We call such decreasing functions type A responses. 2. However, when stress caused mortality, some studies have found that for high stress intensities, survivors performed as well as control individuals (type B responses). We proposed that type A responses are caused by the physiological cost of stress whereas type B responses are caused by a mixture of physiological costs and selection. 3. The present study exposed Aphidius picipes wasps to an increasing duration of cold storage (cold stress), and obtained variable responses as predicted when both physiological costs and selection of resistant individuals determine the outcome. 4. When cold storage of parasitoids for biological control is desirable, research should be carried out to find (i) the temperature regime and duration of storage and (ii) the least sensitive stage for storage to minimise losses from mortality and reduction of fitness of survivors. 5. Selection by cold stress as observed in the present study could result in rapid adaptation of populations exposed to such stress. 相似文献
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目的:比较不同时期颈髓损伤的MRI表现及DTI的应用价值。方法:收集急性颈髓压迫病例15例、慢性颈髓压迫病例23例、颈髓慢性压迫合并急性压迫病例12例。15例健康志愿者作为对照组。进行常规MRI检查,应用DTI检查测量表现扩散系数(ADC)值和各向异性分数(FA)。比较各组间ADC值和FA值,并进行统计学分析。结果:急性颈髓迫病例,常规MRI显示颈髓增粗,呈等T1长T2信号;慢性颈髓压迫病例,9例呈长T1长T2信号,14例呈等T1长T2信号;慢性颈髓压迫并急性压迫病例颈髓明显增粗,呈等、长T1明显长T2信号。与对照组比较:急性颈髓压迫组的ADC值和FA值均明显降低,两组的差异有显著性;慢性颈髓压迫组的FA值降低,ADC值增高,两组的差异有显著性;慢性脊髓压迫合并急性脊髓压迫组ADC值与对照组比较无差异,FA值低于对照组。颈髓压迫各组间ADC值及FA值比较差异显著。结论:不同时期颈髓损伤常规MRI图像缺乏特异性,根据ADC值及FA值可判断颈髓损伤的时期。 相似文献
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ERRATUM: Macho GA and Spears IR. 1999. Effects of Loading on the Biomechanical Behavior of Molars of Homo, Pan, and Pongo. Am J Phys Anthropol 109:211–227. The correct title of the article is given above. The word “biochemical” should be read as “biomechanical.” 相似文献