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41.
MK Berlyn 《Canadian Metallurgical Quarterly》1998,62(3):814-984
This map is an update of the edition 9 map by Berlyn et al. (M. K. B. Berlyn, K. B. Low, and K. E. Rudd, p. 1715-1902, in F. C. Neidhardt et al., ed., Escherichia coli and Salmonella: cellular and molecular biology, 2nd ed., vol. 2, 1996). It uses coordinates established by the completed sequence, expressed as 100 minutes for the entire circular map, and adds new genes discovered and established since 1996 and eliminates those shown to correspond to other known genes. The latter are included as synonyms. An alphabetical list of genes showing map location, synonyms, the protein or RNA product of the gene, phenotypes of mutants, and reference citations is provided. In addition to genes known to correspond to gene sequences, other genes, often older, that are described by phenotype and older mapping techniques and that have not been correlated with sequences are included. 相似文献
42.
Radon concentrations obtained using a bubbler device developed to collect and bubble water samples in the laboratory and field were compared with results from conventional liquid scintillation counting. Measurements from standard solutions with a wide concentration range showed excellent agreement between liquid scintillation and results obtained using the bubbler device in conjunction with alpha-scintillation cells. Measurements of waterborne radon concentrations in 110 community and private wells in New York State ranged from 1 to 4,100 Bq L-1, with arithmetic and geometric means of 200 and 30 Bq L-1, respectively. Excellent agreement between the analytical techniques was obtained for each field site. 相似文献
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J Keane MK Balcewicz-Sablinska HG Remold GL Chupp BB Meek MJ Fenton H Kornfeld 《Canadian Metallurgical Quarterly》1997,65(1):298-304
The effect of Mycobacterium tuberculosis infection on the viability of healthy (control) human alveolar macrophages was evaluated by staining with ethidium homodimer and calcein to discriminate live from dead cells. Infection with M. tuberculosis H37Ra or H37Rv increased macrophage mortality at 6 days from the control level of 3.8% +/- 0.7% to 28.7% +/- 6.9% or 12.6% +/- 3.1%, respectively (P < 0.001 for comparisons of all conditions). A role for tumor necrosis factor alpha (TNF-alpha) in the M. tuberculosis-induced cytolysis of alveolar macrophages was demonstrated by increased cytotoxicity following the addition of exogenous TNF-alpha to the cultures and by enhancement of macrophage survival when M. tuberculosis-infected alveolar macrophages were treated with pentoxifylline or anti-TNF-alpha antibody. The cytolytic mechanism was determined to be apoptosis by the demonstration of a characteristic internucleosomal ladder of genomic DNA by agarose gel electrophoresis, by finding nuclear fragmentation and condensation by electron microscopy, and by in situ terminal transferase-mediated nick end labeling of fragmented DNA in alveolar macrophages infected with M. tuberculosis in vitro. The latter technique was employed to reveal extensive apoptosis within caseating granulomas from lung tissue samples from clinical tuberculosis cases. The induction of apoptosis in alveolar macrophages by M. tuberculosis may play a role in the macrophage-pathogen interaction of tuberculosis in vivo. 相似文献
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MK Moe 《Canadian Metallurgical Quarterly》1991,44(3):R931-R934
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Impaired glucose tolerance (IGT) is associated with defects in both insulin secretion and action and carries a high risk for conversion to non-insulin-dependent diabetes mellitus (NIDDM). Troglitazone, an insulin sensitizing agent, reduces glucose concentrations in subjects with NIDDM and IGT but is not known to affect insulin secretion. We sought to determine the role of beta cell function in mediating improved glucose tolerance. Obese subjects with IGT received 12 wk of either 400 mg daily of troglitazone (n = 14) or placebo (n = 7) in a randomized, double-blind design. Study measures at baseline and after treatment were glucose and insulin responses to a 75-g oral glucose tolerance test, insulin sensitivity index (SI) assessed by a frequently sampled intravenous glucose tolerance test, insulin secretion rates during a graded glucose infusion, and beta cell glucose-sensing ability during an oscillatory glucose infusion. Troglitazone reduced integrated glucose and insulin responses to oral glucose by 10% (P = 0.03) and 39% (P = 0.003), respectively. SI increased from 1.3+/-0.3 to 2.6+/-0.4 x 10(-)5min-1pM-1 (P = 0.005). Average insulin secretion rates adjusted for SI over the glucose interval 5-11 mmol/liter were increased by 52% (P = 0.02), and the ability of the beta cell to entrain to an exogenous oscillatory glucose infusion, as evaluated by analysis of spectral power, was improved by 49% (P = 0.04). No significant changes in these parameters were demonstrated in the placebo group. In addition to increasing insulin sensitivity, we demonstrate that troglitazone improves the reduced beta cell response to glucose characteristic of subjects with IGT. This appears to be an important factor in the observed improvement in glucose tolerance. 相似文献
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The effects of cooperative versus individualistic reward on students' intrinsic motivation were investigated. The controlling aspects of extrinsic reward may be heightened or produce greater ego threat in the individualistic situation when compared with a group situation. We predicted that students in the cooperative social situation would show higher levels of intrinsic motivation. Fifth-grade students from existing cooperative groups were assigned randomly to receive a tangible reward based on either cooperative or individualistic achievement for completing pattern block designs. Cooperation affected intrinsic motivation positively. Students in the cooperative dyad solved the block designs more quickly, interacted positively, and viewed the task as easier than did those in the individualistic situation, and they reported that their peers were helpful. There was little evidence that the controlling functions of reward or ego-threat were factors in producing the outcome. Some evidence supporting the importance of the social nature of cooperation was provided. 相似文献