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排序方式: 共有3495条查询结果,搜索用时 15 毫秒
81.
Y Huang CA Macera SN Blair PA Brill HW Kohl JJ Kronenfeld 《Canadian Metallurgical Quarterly》1998,30(9):1430-1435
PURPOSE: A cohort of middle-aged and older men and women were followed for an average of 5.5 yr to examine the association between physical fitness, physical activity, and the prevalence of functional limitation. METHODS: The participants received medical assessments between 1980 and 1988 and responded to a mail-back survey regarding functional status in 1990. RESULTS: Among 3495 men and 1175 women over 40 yr of age at baseline, 350 (7.5%) reported at least one functional limitation in daily or household activities at follow-up. The prevalence of functional limitation was higher among women than men. Physically fit and physically active participants reported less functional limitation than unfit or sedentary participants. After controlling for age and other risk factors, the prevalence of functional limitation was lower for both moderately fit (odds ratio = 0.4, 95% CI = 0.2-0.6) and high fit men (odds ratio = 0.3, 95% CI = 0.2-0.4), compared with low fit men. Corresponding figures for women were 0.5 (0.3-0.7) and 0.3 (0.2-0.5) for moderately fit and high fit women. The association between physical activity and functional limitation was similar to the data for physical fitness. CONCLUSIONS: These data support a protective effect of physical fitness and physical activity on functional limitation among older adults and extend this protective effect to middle-aged men and women. 相似文献
82.
83.
We have isolated an insertional mutant of Dictyostelium discoideum that aggregated rapidly and formed spores and stalk cells within 14 h of development instead of the normal 24 h. We have shown by parasexual genetics that the insertion is in the rdeA locus and have cloned the gene. It encodes a predicted 28 kDa protein (RdeA) that is enriched in charged residues and is very hydrophilic. Constructs with the DNA for the c-Myc epitope or for the green fluorescent protein indicate that RdeA is not compartmentalized. RdeA displays homology around a histidine residue at amino acid 65 with members of the H2 module family of phosphotransferases that participate in multistep phosphoryl relays. Replacement of this histidine rendered the protein inactive. The mutant is complemented by transformation with the Ypd1 gene of Saccharomyces cerevisiae, itself an H2 module protein. We propose that RdeA is part of a multistep phosphorelay system that modulates the rate of development. 相似文献
84.
To assess the completeness of human immunodeficiency virus (HIV) reporting among hospital inpatients whose records listed diagnostic codes for HIV infection but who did not meet the 1987 AIDS case definition, we conducted a statewide hospital study of admissions between January 1, 1986 and December 31, 1990. Of the 396 HIV-infected hospital inpatients identified, 313 (79%) had been reported to the State HIV Registry. HIV reporting was less complete for patients who were older and/or were blood product recipients. Of the 313 reported patients, 189 (60%) had been reported prior to their first hospital admission. Temporal improvements were noted in the completeness of HIV reporting among the hospital patients (1986: 65%; 1987: 81%; 1988: 64%; 1989: 82%; 1990: 86%; Chi square for linear trend 9.6, p < 0.01) and prior to their first hospital admission (1986: 31%; 1987: 34%; 1988: 49%; 1989: 64%; 1990: 72%; Chi square for linear trend 26.6; p < 0.01). Women were more likely than men to be reported prior rather than during or after their first hospital admission (71% vs. 55%; p < 0.01). Of the 155 patients with CD4+ T-lymphocyte test results, 41 had CD4+ counts < 200 mm3 and met the 1993 but not the 1987 AIDS case definition. In South Carolina most (79%) diagnosed, hospitalized, HIV-infected patients had been reported to the State HIV REgistry, with improvements in reporting occurring over time. Findings suggest that the 1993 AIDS case definition will improve our ability to monitor severe morbidity related to HIV. 相似文献
85.
Hydrolysis studies using simulated gastrointestinal fluids have been performed on oleamide, an important fatty acid amide slip additive used in plastics food packaging. Experiments have been conducted using the simulated gastrointestinal fluids, specified by the Scientific Committee for Food for hydrolysis studies, and with slightly modified preparations believed to be more representative of the in vivo situation. The degree of hydrolysis in simulated gastric fluids was found to be negligible after incubation for 4 h at 37 degrees C. Addition of 'bile salts' to simulated intestinal fluid was found to significantly increase the degree of hydrolysis to about 95% loss of oleamide after incubation for 4 h at 37 degrees C. Stoichiometric formation of oleic acid, an innocuous substance, was also demonstrated. It has therefore been concluded that ingestion of the very low levels of oleamide expected to migrate into most foods from food packaging is unlikely to pose a threat to the health of the consumer. 相似文献
86.
PA N JinChangsha Institute of Technology ChinaLI Jihong NING Xiaoguang YE HengqiangLab. of Atomic Imaging of Solids Institute of Metal Research Chinese Academy of Sciences. Shenyang China Manuscript received February 《金属学报(英文版)》1994,7(2):119-123
A newly developed whisker K_2O 6TiO_2 reinforeed 6061Al composite was prepared bysqueeze casting process.The flexural strength of the composite is 518MPa,and deereasesto 490MPa after T6 treatment.The hardness of the composite also shows the similarchange while T6 treating.The results of HRTEMobservation may explaine this property.change.It was considered that there is a continuous TiO layer at the whisker-matrix inter-face,which is easily to react with the segregated Mg and to form MgTi_2O_4,MgAl_2O_4.Thethickening of TiO layer after T6 treatment is the main reason resulting is strength degra-dation of composite. 相似文献
87.
基于WebGIS的城市供水管网系统的设计与实现 总被引:1,自引:0,他引:1
介绍了基于WebGIS的城市供水管网信息系统的体系结构、功能组成以及供水管网建模技术.城市供水管网系统主要包括管网建模、查询统计、爆管事故分析、运行状态监控、漏损分析、系统维护等六个方面.城市供水管网建模是进行城市供水系统规划、设计、分析与优化调度的重要支撑技术,充分发挥WebGIS的分布式与可视化地理空间信息分析的优势,结合城市供水管网的管理需求,将WebGIS技术应用到城市供水管网的建模中.该系统可为城市供水部门的高效管理提供决策依据. 相似文献
88.
PA Field 《Canadian Metallurgical Quarterly》1994,31(2):201-215
In this survey research a comparison was made between symptoms used by mothers and nurses which led them to think the baby might be "colicky." Two questionnaires, one for mothers and one for nurses, were used to collect the data. The mothers most frequently selected passes gas rectally, clenches fists, draws-up legs, cries late afternoon and evening, holds body straight, and wants to be held. The nurses selected mother states baby is inconsolable, cries more than 4 hours in 24, draws up legs and wants to feed but won't. Parents believed the colic to be related to a variety of factors; these included baby's eating behaviour, maternal anxiety, baby's and mother's diets, and baby's stress. Ten parents reported pain and screaming as symptoms of colic. 相似文献
89.
Integral and membrane-associated proteins extracted from neuron-enriched perirhopalial tissue of the jellyfish Cyanea capillata were probed with a panel of lectins that recognize sugar epitopes of varying complexity. Of the 13 lectins tested, only concanavalin A, jacalin lectin and tomato lectin stained distinct bands on Western blots, indicating the presence of repeating alpha-1,6-mannoses, terminal Gal-alpha-1,6-GalNAc and repeating beta-1,4-linked GlcNAc, respectively. In whole-mounted perirhopalial tissue, jacalin lectin stained several cell types, including neurons, muscle, cilia and mucus strands. Tomato lectin stained secretory cells intensely, and neurons in a punctate fashion. Concanavalin A stained cytoplasmic epitopes in both ecto- and endodermal cells, and ectodermal secretory cells and the mucus strands emanating from them. With the exception of tomato lectin's sugar epitope, the other sugar epitopes identified in this study are "non-complex". This study suggests that while glycosylation of integral and membrane-associated proteins occurs in Cyanea, the sugars post-translationally linked to these proteins tend to be simple. 相似文献
90.
JA DeMartino ZD Konteatis SJ Siciliano G Van Riper DJ Underwood PA Fischer MS Springer 《Canadian Metallurgical Quarterly》1995,270(27):15966-15969
C5a is a 74-amino-acid glycoprotein whose receptor is a member of the rhodopsin superfamily. While antagonists have been generated to many of these receptors, similar efforts directed at family members whose natural ligands are proteins have met with little success. The recent development of hexapeptide analogs of C5a has allowed us to begin elucidation of the molecular events that lead to activation by combining a structure/activity study of the ligand with receptor mutagenesis. Removal of the hexapeptide's C-terminal arginine reduces affinity by 100-fold and eliminates the ability of the ligand to activate the receptor. Both the guanidino side chain and the free carboxyl of the arginine participate in the interaction. The guanidino group makes the energy-yielding contact with the receptor, while the free carboxylate negates "electrostatic" interference with Arg-206 of the receptor. It is the apparent movement Arg-206 induced by this set of interactions that is responsible for activation, since conversion of Arg-206 to alanine eliminates the agonist activity of the hexapeptides. Surprisingly, activation is a nearly energy-neutral event and may reflect the binding process rather than the final resting site of the ligand. 相似文献