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941.
I Stewart L McNaughton P Davies S Tristram 《Research quarterly for exercise and sport》1990,61(1):80-84
It is known that an increased level of red blood cell 2,3-diphosphoglycerate (DPG) shifts the oxyhemoglobin dissociation curve to the right, thus allowing a greater unloading of oxygen at the tissue level. It has been hypothesized that phosphate might help increase VO2max by increasing 2,3-DPG level. Eight trained cyclists underwent three cycle ergometer tests (control, placebo, and experimental) to determine whether phosphate ingestion had any positive effect on VO2max, time to exhaustion, serum 2,3-DPG, and serum phosphate levels. We found no change between the control, placebo, or experimental conditions in pretest serum phosphate levels, but we did find increases in 2,3-DPG levels in the phosphate condition (p less than .05), which suggests that even a small amount of phosphate could increase levels of 2,3-DPG. We also found significant differences in VO2max between the control (p less than .05) and placebo (p less than .02) conditions and also in time to exhaustion between the three conditions (p less than .05). We suggest that phosphate may have an ergogenic effect, but clearly more work needs to be undertaken to ascertain the amount of phosphate required and the magnitude of the effect. 相似文献
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943.
R J Markert A J Parisi H V Barnes S Cohen K Goldenberg L E Mieczkowski M Dunn R M Siervogel 《Bulletin of the Medical Library Association》1989,77(2):133-138
The experiences of medical students, residents, and faculty with a computerized literature searching system were evaluated. Third-year medical students, internal medicine and family practice residents, and full-time and voluntary faculty at one medical school had the opportunity to use a full-text and bibliographic medical literature retrieval system free of charge for an eleven-month period. Subjects conducted nearly nine thousand literature searches over a period of 942 system hours. Questionnaire data showed that participants could learn to use and would use an electronic information system, felt capable of using the system, utilized the system for a variety of purposes and in a number of different ways, and viewed the system as a valuable tool in searching the medical literature. The results are discussed in the context of the educational needs of the four user-groups and medical education planning by institutions. 相似文献
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949.
Design and synthesis of chiral Ti-1,1′-bi-2-naphthol coordination polymers for heterogeneous catalytic asymmetric oxidation of sulfides
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袁小亚 《重庆大学学报(英文版)》2008,(3)
Polymer-immobilized catalysis has many advantages such as easy recovery and reuse of catalyst. We prepared three novel chiral 1,1′-bi-2-naphthol-Ti coordination polymers with properly designed ligands and Ti(OiPr)4 under mild conditions. The prepared polymers exhibited good activity and excellent enantioselectivity (over 99%ee) in catalyzing the asymmetric oxidation of sulfides. The bridge linker in the polymer and the reaction solvent noticeably affected the enantioselectivity. The chiral coordination poly... 相似文献
950.
Sandra K. Faull 《Government Information Quarterly》1985,2(2):157-167
Many librarians affiliated with regional depositories are concerned about the ability of their libraries to receive, process, store, and service all the titles and series available on deposit from the Government Printing Office. Some of them have even questioned whether their library can maintain regional status and fulfill all the service elements specified in the Guidelines for the Depository Library System (1977). As this article demonstrates, regional librarians supported the concept of state plans because they believed that this process offered an excellent means to address their concerns. However, in only a few instances have the plans fulfilled the purpose which regional staff envisioned. Nonetheless, the foundation which they laid, if pursued and if the basic documentation underlying the depository program are rewritten, could lead to the type of changes sought by regional libraries. 相似文献