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131.
A case of dextrocardia with normal situs.   总被引:1,自引:0,他引:1  
We report here a case of dextrocardia with normal situs in an 81-year-old man who died from non-pulmonary causes. Removal of the chest wall revealed a large, but otherwise anatomically normal, left lung occupying the entire left hemithorax and extending across the midline to overlap the left border of the heart which was positioned in the right hemithorax. The gross anatomy of the heart was normal save its position and the presence of only 2 pulmonary veins. Dissection of the heart showed all chambers in their classically described position, and there were no valvular defects. The anatomy of the great vessels was also normal. The right lung was hypoplastic and lay posterior to the heart. This lung lacked any lobular structure, but the presence of carbon particles throughout it suggested that it was capable of normal inflation.  相似文献   
132.
An encased incident-light microscope was constructed for use underwater to determine the relative abundances of micro-organisms living on natural sublittoral substrata in an Ecklonia radiata (C. Agardh) J. Agardh forest. By comparisons of data gathered using the microscope with data obtained from microscopic sampling of chips of natural substratum in the laboratory, the practicality and accuracy of the underwater microscope could be assessed. The repeatability of microscopic sampling in the field was determined by sampling certain areas of natural forest twice on the same day.A pilot survey of natural substrata in the kelp forest was done to determine patterns of spatial variability in the distribution of organisms sampled with the microscope. Analyses of variance and cost-benefit analyses of these data allowed calculation of optimal patch sizes and numbers of replicates to be used in future experiments. The importance of testing field methodologies and pilot studies was noted.  相似文献   
133.
Food intake of captive cotton-top tamarins was measured at various stages of the life cycle and energy intake was calculated from the results. The intake of adults for maintenance was found to vary around 500 kJ X kg-3/4 X day-1 and to decrease with age. During the last 8 weeks of pregnancy, females increased in weight by about 2 g X day-1 but energy intake did not show a marked rise above the maintenance range. During lactation, their energy intake appeared to double. Measurements of intake at various stages of growth were compared with a model of the energy requirements for growth which predicted intake quite closely. Compared with non-primate mammals of similar size, the growth rate of this species is slow, and because of this, the energy intake during growth and lactation is also comparatively low.  相似文献   
134.
Five different species of freshwater bacteria ( Pseudomonas sp., Vibrio sp., Klebsiella sp., Enterobacter sp., Serratia sp.) and a mixed natural population were used separately to inoculate cultures of axenic duckweed ( Lemna minor ). Inoculation with Vibrio sp. caused the final population density of Lemna plants to be significantly greater after 52 d than that of either axenic controls or Lemna inoculated with a mixed bacterial community. Inoculation with Pseudomonas sp. caused the final population density of Lemna to be significantly higher than with the mixed bacterial treatment. Inoculation of Lemna with Klebsiella sp., Enterobacter sp. or Serratia sp. resulted in higher plant populations compared with controls, but these differences were not statistically significant. The presence of a mixed community of bacteria did not significantly affect the final population density of Lemna compared with the controls. However, Lemna plants inoculated with a natural population of bacteria showed significantly higher levels of senescence compared with the other five treatments and the controls. None of the five single bacterial taxa used appeared to have any significant effect of the sensescence of duckweed.  相似文献   
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Virus gene sequencing and phylogenetics can be used to study the epidemiological dynamics of rapidly evolving viruses. With complete genome data, it becomes possible to identify and trace individual transmission chains of viruses such as influenza virus during the course of an epidemic. Here we sequenced 153 pandemic influenza H1N1/09 virus genomes from United Kingdom isolates from the first (127 isolates) and second (26 isolates) waves of the 2009 pandemic and used their sequences, dates of isolation, and geographical locations to infer the genetic epidemiology of the epidemic in the United Kingdom. We demonstrate that the epidemic in the United Kingdom was composed of many cocirculating lineages, among which at least 13 were exclusively or predominantly United Kingdom clusters. The estimated divergence times of two of the clusters predate the detection of pandemic H1N1/09 virus in the United Kingdom, suggesting that the pandemic H1N1/09 virus was already circulating in the United Kingdom before the first clinical case. Crucially, three clusters contain isolates from the second wave of infections in the United Kingdom, two of which represent chains of transmission that appear to have persisted within the United Kingdom between the first and second waves. This demonstrates that whole-genome analysis can track in fine detail the behavior of individual influenza virus lineages during the course of a single epidemic or pandemic.  相似文献   
139.
Synthesis and in vitro evaluation of [(18)F](R)-N-(4-bromo-2-fluorophenyl)-7-((1-(2-fluoroethyl)piperidin-3-yl)methoxy)-6-methoxyquinazolin-4-amine ((R)-[(18)F]FEPAQ or [(18)F]1), a potential imaging agent for the VEGFR2, using phosphor image autoradiography are described. Synthesis of 2, the desfluoroethyl precursor for (R)-FEPAQ was achieved from t-butyl 3-(hydroxymethyl)piperidine-1-carboxylate (3) in five steps and in 50% yield. [(18)F]1 was synthesized by reaction of sodium salt of compound 2 with [(18)F]fluoroethyl tosylate in DMSO. The yield of [(18)F]1 was 20% (EOS based on [(18)F]F(-)) with >99% radiochemical purity and specific activity of 1-2 Ci/μmol (n=10). The total synthesis time was 75 min. The radiotracer selectively labeled VEGFR2 in slide-mounted sections of human brain and higher binding was found in surgically removed human glioblastoma sections as demonstrated by in vitro phosphor imager studies. These findings suggest [(18)F]1 may be a promising radiotracer for imaging VEGFR2 in brain using PET.  相似文献   
140.
Tolerance to herbivory (the degree to which plants maintain fitness after damage) is a key component of plant defense, so understanding how natural selection and evolutionary constraints act on tolerance traits is important to general theories of plant–herbivore interactions. These factors may be affected by plant competition, which often interacts with damage to influence trait expression and fitness. However, few studies have manipulated competitor density to examine the evolutionary effects of competition on tolerance. In this study, we tested whether intraspecific competition affects four aspects of the evolution of tolerance to herbivory in the perennial plant Solanum carolinense: phenotypic expression, expression of genetic variation, the adaptive value of tolerance, and costs of tolerance. We manipulated insect damage and intraspecific competition for clonal lines of S. carolinense in a greenhouse experiment, and measured tolerance in terms of sexual and asexual fitness components. Compared to plants growing at low density, plants growing at high density had greater expression of and genetic variation in tolerance, and experienced greater fitness benefits from tolerance when damaged. Tolerance was not costly for plants growing at either density, and only plants growing at low density benefited from tolerance when undamaged, perhaps due to greater intrinsic growth rates of more tolerant genotypes. These results suggest that competition is likely to facilitate the evolution of tolerance in S. carolinense, and perhaps in other plants that regularly experience competition, while spatio-temporal variation in density may maintain genetic variation in tolerance.  相似文献   
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