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排序方式: 共有1233条查询结果,搜索用时 31 毫秒
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Processes based upon solid sorbents are currently under consideration for post-combustion CO2 capture. Twenty-four different sorbent materials were examined on a laboratory scale in a cyclic temperature swing adsorption/regeneration CO2 capture process in simulated coal combustion flue gas. Ten of these materials exhibited significantly lower theoretical regeneration energies compared to the benchmark aqueous monoethanolamine, supporting the hypothesis that CO2 capture processes based upon solids may provide cost benefits over solvent-based processes. The best performing materials were tested on actual coal-fired flue gas. The supported amines exhibited the highest working CO2 capacities, although they can become poisoned by the presence of SO2. The carbon-based materials showed excellent stability but were generally categorized as having low CO2 capacities. The zeolites worked well under dry conditions, but were quickly poisoned by the presence of moisture. Although no one type of material is without concerns, several of the materials tested have theoretical regeneration energies significantly lower than that of the industry benchmark, warranting further development research. 相似文献
93.
Sharon N. Greenwood Dr. Rashmi S. Kulkarni Dr. Michel Mikhail Dr. Brian P. Weiser 《Chembiochem : a European journal of chemical biology》2023,24(10):e202200765
DNA repair proteins participate in extensive protein−protein interactions that promote the formation of DNA repair complexes. To understand how complex formation affects protein function during base excision repair, we used SpyCatcher/SpyTag ligation to produce a covalent complex between human uracil DNA glycosylase (UNG2) and replication protein A (RPA). Our covalent “RPA−Spy−UNG2” complex could identify and excise uracil bases in duplex areas next to ssDNA−dsDNA junctions slightly faster than the wild-type proteins, but this was highly dependent on DNA structure, as the turnover of the RPA−Spy−UNG2 complex slowed at DNA junctions where RPA tightly engaged long ssDNA sections. Conversely, the enzymes preferred uracil sites in ssDNA where RPA strongly enhanced uracil excision by UNG2 regardless of ssDNA length. Finally, RPA was found to promote UNG2 excision of two uracil sites positioned across a ssDNA−dsDNA junction, and dissociation of UNG2 from RPA enhanced this process. Our approach of ligating together RPA and UNG2 to reveal how complex formation affects enzyme function could be applied to examine other assemblies of DNA repair proteins. 相似文献
94.
Cervically inseminated cryopreserved ram spermatozoa have reduced fertility due to poor mucus-penetrating ability. This effect is ameliorated by the addition of 20% (v/v) seminal plasma (SP) to the phosphate-buffered saline (PBS) thawing medium. The aims of this study were to determine whether the impaired mucus penetration was due to alterations in the sperm motility and, if so, whether these alterations were due to the SP or its viscosity, or to the medium components. To this end, artificial SP medium (ASP), a medium which supports motility but not capacitation, was compared with PBS and SP. Thawed, pooled semen from seven mature rams was layered under 1 ml each of PBS, SP and ASP and motile spermatozoa allowed to swim up (37 degrees C, 30 min). Upper regions of the overlays were harvested, and the capacitation status of the spermatozoa in each suspension determined by chlortetracycline (CTC) analysis. Sperm movement was videotaped in 300 microm chambers for both computer-aided sperm analysis assessment and manual flagellar curvature analysis. There was no effect of the culture medium on the concentration of spermatozoa recovered by swim up, nor on the proportion of motile spermatozoa. However, the spermatozoa resuspended in PBS did show changes associated with capacitation in both the CTC-binding patterns and in their movement patterns. These changes were significantly greater than those observed in spermatozoa resuspended in SP or ASP. These results indicated that the differences in sperm movement and function observed in SP medium were not due to changes in viscosity, but rather to components of the medium. 相似文献
95.
Sharon L Woodward Alexandre V Chaves Garry C Waghorn Ian M Brookes Jennifer L Burke 《Journal of the science of food and agriculture》2006,86(8):1263-1270
A trial was conducted to compare benefits obtained from feeding four types of silage. There were two silages that contained condensed tannins (CT)—lotus (Lotus corniculatus) and sulla (Hedysarum coronarium)—maize silage or traditional ryegrass pasture silage, all fed at 5 kg dry matter (DM) cow?1 day?1 with restricted pasture (RP). Cows on the RP (control) treatment and those fed the silage treatments were offered an allowance of 25 kg pasture DM cow?1 day?1, while the full pasture (FP) cows were offered 50 kg pasture DM cow?1 day?1. Silage supplementation increased both DM intake and milk yield compared with cows given RP only. Cows on the lotus silage supplement and the FP treatment had significantly higher milk production than the other silage supplemented cows (P < 0.001). For cows given lotus silage, the high milk yield was probably due to a combination of the higher nutritive value of the silage and possibly to the protein‐sparing effects of the lotus condensed tannins because the total DM intake of cows fed the lotus silage was the same as that of cows given the pasture and maize silages (P > 0.25). The high milk yield of the FP treatment was mainly a result of the cows having a higher intake of pasture than cows on all the other treatments. This study demonstrated the potential benefit of silage supplementation, particularly with lotus silage, for increased milksolids yield in summer when low pasture growth rates and quality may otherwise limit production. Copyright © 2006 Society of Chemical Industry 相似文献
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98.
Sharon Hornstein Tal Langer Tsuri Assis Arnon Hirshberg 《Journal of the Society for Information Display》2010,18(10):862-867
Abstract— A new raster‐scanning chipset which provides enhanced projection performance is presented. The design is novel in that it combines electrostatic and electromagnetic actuation methods, along with a unique feedback‐control scheme to produce SVGA and WVGA projected images. A micromirror, the actuators, and drive electronics are integrated into a small, power‐efficient system, a scanning chipset, to increase its reliability and manufacturability. 相似文献
99.
Assessing a patient's access to potentially lethal means for suicide and taking steps to restrict access to means are common expectations for reasonable outpatient management of suicidal patients. Although scientific evidence supports means restriction as a suicide prevention strategy, means restriction continues to be infrequently utilized by clinicians, in large part because of the general lack of available training and guidance. The present article reviews the conceptual basis and empirical evidence for means restriction, discusses common barriers to means-restriction counseling, and provides practical procedures and tools (e.g., the means receipt, the crisis support plan) for accomplishing means-restriction counseling in routine clinical practice. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
100.
Foster Sharon L.; Laverty-Finch Cambra; Gizzo Daniel P.; Osantowski Janay 《Canadian Metallurgical Quarterly》1999,11(4):426
Using self-observation as a clinical or research tool requires attention to a number of practical concerns. In this article, issues involved in selecting a self-observation method are considered, including determining the dimension of behavior to be observed and choosing a method and recording device for sampling behavior. The literature on training individuals to self-observe, which supports the importance of comprehensive multicomponent training, is surveyed. Also considered are ways of evaluating and improving data quality as the self-observer collects information and of engineering compliance with requests to self-monitor. Future research should (a) systematically examine ways of obtaining high-quality self-observation data and enhancing participant compliance and (b) extend findings of older investigations both to contemporary methods of collecting information and to self-observation of private events. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献