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排序方式: 共有195条查询结果,搜索用时 15 毫秒
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David G. Temesi Scott Martin Robin Smith Christopher Jones Brian Middleton 《Rapid communications in mass spectrometry : RCM》2010,24(12):1730-1736
Screening assays capable of performing quantitative analysis on hundreds of compounds per week are used to measure metabolic stability during early drug discovery. Modern orthogonal acceleration time‐of‐flight (OATOF) mass spectrometers equipped with analogue‐to‐digital signal capture (ADC) now offer performance levels suitable for many applications normally supported by triple quadruple instruments operated in multiple reaction monitoring (MRM) mode. Herein the merits of MRM and OATOF with ADC detection are compared for more than 1000 compounds screened in rat and/or cryopreserved human hepatocytes over a period of 3 months. Statistical comparison of a structurally diverse subset indicated good agreement for the two detection methods. The overall success rate was higher using OATOF detection and data acquisition time was reduced by around 20%. Targeted metabolites of diazepam were detected in samples from a CLint determination performed at 1 µM. Data acquisition by positive and negative ion mode switching can be achieved on high‐performance liquid chromatography (HPLC) peak widths as narrow as 0.2 min (at base), thus enabling a more comprehensive first pass analysis with fast HPLC gradients. Unfortunately, most existing OATOF instruments lack the software tools necessary to rapidly convert the huge amounts of raw data into quantified results. Software with functionality similar to open access triple quadrupole systems is needed for OATOF to truly compete in a high‐throughput screening environment. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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D. G. Middleton J. R. M. Annand C. Barbieri C. Giusti P. Grabmayr T. Hehl I. J. D. MacGregor I. Martin J. C. McGeorge F. Moschini F. D. Pacati M. Schwamb D. Watts 《The European Physical Journal A - Hadrons and Nuclei》2010,43(2):137-143
After recent improvements to the Pavia model of two-nucleon knockout from 16O with electromagnetic probes the calculated cross-sections are compared to experimental data from such reactions. Comparison with data from a measurement of the 16O (e,e’ pn) reaction cross-section shows much better agreement between the experimental data and the results of the theoretical model than was previously observed. In a comparison with recent data from a measurement of the 16O ( $ \gamma$ ,pn) reaction cross-section the model over-predicts the measured cross-section at low missing momentum. 相似文献
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The effect of ozone and high temperature on polymer degradation in polymer core composite conductors
James Middleton Brian Burks Todd Wells Alexander M. Setters Iwona Jasiuk Maciej Kumosa 《Polymer Degradation and Stability》2013
The next generation High Temperature Low Sag Polymer Core Composite Conductors can experience harsh in-service environments including high temperature and highly concentrated ozone. In some extreme cases, it is possible that the conductors will experience temperatures of up to 180 °C and ozone concentrations as high as 1% (10,000 ppm). Therefore, the goal of this work was to understand the degradation mechanisms in a high temperature epoxy, which could be used in the conductors at temperatures as high as 140 °C in the presence of 1% ozone. Then, the combined aging data for the epoxy were compared to the aging results from room temperature aging in 1% ozone and aging in air at 140 and 180 °C. In addition, important but limited aging testing was also performed on a set of PCCC rods to verify some of the observations from the neat resin experiments. It was determined that the mass loss, volumetric shrinkage, and flexural strength reductions of the epoxy aged at 140 °C were driven almost entirely by temperature and that the effect of 1% ozone at that temperature can be thought of as insignificant for aging times up to 90 days. The composite rods displayed postcuring at 140 °C and were also unaffected by the presence of ozone at aging time lengths of 90 days. Up to this time aging the polymer and composite specimens in atmospheric 180 °C resulted in the most drastic changes in both physical and mechanical properties, except viscoelasticity where the polymer specimens aged at 140 °C with 1% ozone showed the greatest increase in the storage modulus. The least amount of degradation to the materials was found to occur after aging at room temperature in 1% ozone. 相似文献
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A hierarchical micromagnetic model has been used to investigate the effect of reducing track width upon recorded transition noise in longitudinal thin films. This has demonstrated that although effects due to magnetization transtion profile variations can be accounted for by simple statistics, timing jitter is a more complex phenomenon. 相似文献
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It is shown that collision operators defined by the projector of Argyres and Kelley may provide useful examples for study of the subdynamics of the Brussels group. An application of this formalism to the optical pumping model of Barrat and Cohen-Tannoudji is discussed. 相似文献
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