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981.
An investigation of the binding sites of proteins S8, L23 and L24 on the ribosomal RNAs of Escherichia coli by electron microscopy 总被引:1,自引:0,他引:1
The rigid fixation of bone fragments by compression osteosynthesis with plate produces a high degree of resistance against bending forces, and over the surface friction against rotatory movements. In this way, a uniform distribution of pressure extending over the whole bone section is effected. But by virtue of the asymmetric positioning of the plate on bone-shaft, a torque effect is caused when strain is applied bringing about a distraction of the cortex on the side opposite the plate. Human femoral and tibial specimens would be osteomatized and then stabilized with AO plate adapted to conform to the surface of the bones, under a tension of 70 and 140 kp. With narrow plates having a inferior rigidity there is a greater distraction than is the cause with the wide plates. To compensate against the torque effect, the plates would be prebent. Two measuring methods would be investigate by which the correlation between prestraining and prebending could be determined. To achieve a constant distribution of pressure the narrow plates would have to be prebent to a greater degree than the wide ones, and the DC plates more than the standard plates. 相似文献
982.
R. Wayne Garrett David J. T. Hill James H. O'Donnell Peter J. Pomery Catherine L. Winzor 《Polymer Bulletin》1989,22(5-6):611-616
Summary The concentration of propagating radicals during the free radical polymerization of methyl methacrylate in bulk to high conversion at 60°C was determined — (1) by in situ measurements in the spectrometer, and (2) using a cryogenic quenching procedure. The radical concentration showed a sigmoidal relationship with polymerization time, and the conformation of the radical was different below and above the gel point of ca. 30% conversion. A value of kt=2.5 (±0.3)×107 1 mol–1 s–1 was obtained below the gel point. The variation in kt, without allowance for a decreasing efficiency factor (f), was determined over the entire conversion range. 相似文献
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984.
Some scholars worry that Instant Messaging (IM), by virtue of the ease with which users can initiate and participate in online conversations, contributes to an increase in task interruption. Others argue that workers use IM strategically, employing it in ways that reduce interruption. This article examines the relationship between IM and interruption, using data collected via a (U.S.) national telephone survey of full-time workers who regularly use computers (N = 912). Analysis of these data indicates that IM use has no influence on overall levels of work communication. However, people who utilize IM at work report being interrupted less frequently than non-users, and they engage in more frequent computer-mediated communication than non-users, including both work-related and personal communication. These results are consistent with claims that employees use IM in ways that help them to manage interruption, such as quickly obtaining task-relevant information and negotiating conversational availability. 相似文献
985.
Pile Spacing Effects on Lateral Pile Group Behavior: Analysis 总被引:1,自引:0,他引:1
Kyle M. Rollins Kimball G. Olsen Derek H. Jensen Brian H. Garrett Ryan J. Olsen Jeffery J. Egbert 《Canadian Metallurgical Quarterly》2006,132(10):1272-1283
Using the results from three full-scale lateral pile group load tests in stiff clay with spacing ranging from 3.3 to 5.65, computer analyses were performed to back-calculate p multipliers. The p multipliers, which account for reduced resistance due to pile–soil–pile interaction, increased as pile spacing increased from 3.3 to 5.65 diameters. Extrapolation of the test results suggests that group reduction effects can be neglected for spacings greater than about 6.5 for leading row piles and 7–8 diameters for trailing row piles. Based on analysis of the full-scale test results, pile behavior can be grouped into three general categories, namely: (1) first or front row piles; (2) second row piles; and (3) third and higher row piles. p multiplier versus normalized pile spacing curves were developed for each category. The proposed curves yield p multipliers which are higher than those previously recommended by AASHTO in 2000, the US Army in 1993, and the US Navy in 1982 based on limited test data, but lower values than those proposed by Reese et al. in 1996 and Reese and Van Impe in 2001. The response (load versus deflection, maximum moment versus load, and bending moment versus depth) for each row of the pile groups computed using GROUP and Florida Pier generally correlated very well with measurements from the full-scale tests when the p multipliers developed from this test program were employed. 相似文献
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1. The pharmacokinetics of methyldopa after oral and intravenous administration was studied in hypertensive and normotensive patients. After intravenous administration methyldopa plasma concentrations decayed according to a two-compartment open model. 2. For intravenous administration the overall elimination constant Ke1 was 0.56 +/- 0.03 h-1, the volume of distribution of the central compartment 0.29 +/- 0.80 1 kg-1 and the plasma clearance rate 11.2 +/- 0.6 1 h-1. 3. Plasma half-times during the beta-phase of the methyldopa plasma decay curve following intravenous and oral administration were 2.8 +/- 1.3 and 2.1 +/- 0.7 h, respectively. 4. Maximal plasma levels in hypertensive out-patients show great variation and range from 0 to 1.9 microgram ml-1. 5. No relationships were found between maximal methyldopa plasma levels in patients under treatment and control of hypertension. 相似文献