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41.
LC-MS/MS has been widely applied to the quantitative analysis of tissue samples. However, one key remaining issue is that the extraction recovery of analyte from spiked tissue calibration standard and quality control samples (QCs) may not accurately represent the “true” recovery of analyte from incurred tissue samples. This may affect the accuracy of LC-MS/MS tissue bioanalysis. Here, we investigated whether the recovery determined using tissue QCs by LC-MS/MS can accurately represent the “true” recovery from incurred tissue samples using two model compounds: BMS-986104, a S1P1 receptor modulator drug candidate, and its phosphate metabolite, BMS-986104-P. We first developed a novel acid and surfactant assisted protein precipitation method for the extraction of BMS-986104 and BMS-986104-P from rat tissues, and determined their recoveries using tissue QCs by LC-MS/MS. We then used radioactive incurred samples from rats dosed with 3H-labeled BMS-986104 to determine the absolute total radioactivity recovery in six different tissues. The recoveries determined using tissue QCs and incurred samples matched with each other very well. The results demonstrated that, in this assay, tissue QCs accurately represented the incurred tissue samples to determine the “true” recovery, and LC-MS/MS assay was accurate for tissue bioanalysis. Another aspect we investigated is how the tissue QCs should be prepared to better represent the incurred tissue samples. We compared two different QC preparation methods (analyte spiked in tissue homogenates or in intact tissues) and demonstrated that the two methods had no significant difference when a good sample preparation was in place. The developed assay showed excellent accuracy and precision, and was successfully applied to the quantitative determination of BMS-986104 and BMS-986104-P in tissues in a rat toxicology study.  相似文献   
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43.
Monoclonal antibodies against the hop-derived prenylated chalcone xanthohumol (X) and the prenylated flavonoids isoxanthohumol (IX) and 8-prenylnaringenin (8-PN) were developed. Carboxylic acid haptens of X, IX and 8-PN were synthesized by linking a spacer to their C4′-OH group followed by subsequent coupling to bovine serum albumin (BSA) to form conjugates that were employed as immunogens in BALB/c mice to raise antibodies. The monoclonal antibodies that were secreted from the established hybridoma cell lines proved, in cross-reactivity studies, to possess highly specific binding capacities in an optimized competitive indirect ELISA. The immunoassays make use of immunogen-coated microtiterplates and a peroxidase-labeled anti-mouse IgG1 secondary antibody with ABTS as a chromogenic substrate. For X the IC50 value derived from the standard curve was 62.91 ng mL−1, and for both IX and 8-PN 37.15 ng mL−1. The assay was validated for the quantitative analysis of X, IX and 8-PN in urine and serum. A simple sample pretreatment procedure using a diethyl ether extraction was optimized and the recoveries and matrix effects were assessed. The validity of the established assay was tested and mean inter- and intra-assay variations in urine were 2.32% and 1.91%, respectively for X, 6.24% and 2.39%, respectively for IX and 7.18% and 0.74%, respectively for 8-PN. In serum, the mean inter- and intra-assay variations were 8.90% and 1.37%, respectively for X, 6.13% and 1.57%, respectively for IX and 6.13% and 2.43%, respectively for 8-PN. Furthermore, the method demonstrated excellent accuracy and significant correlation with measurements by an established and validated HPLC-MS method.  相似文献   
44.
Water matrix certified reference material (MCRM) of volatile organic compounds (VOCs) is used to provide quality assurance and quality control (QA/QC) during the analysis of VOCs in water. In this research, a water MCRM of 28 VOCs was developed using a “reconstitution” approach by adding VOCs spiking, methanol solution into pure water immediately prior to analysis. The VOCs spiking solution was prepared gravimetrically by dividing 28 VOCs into seven groups, then based on ISO Guide 35, using gas chromatography-mass spectrometry (GC-MS) to investigate the homogeneity and long-term stability. The studies of homogeneity and long-term stability indicated that the batch of VOCs spiking solution was homogeneous and stable at room temperature for at least 15 months. Moreover, the water MCRM of 28 VOCs was certified by a network of nine competent laboratories, and the certified values and expanded uncertainties of 28 VOCs ranged from 6.2 to 17 μg/L and 0.5 to 5.3 μg/L, respectively.  相似文献   
45.
统计分析了2009年FY-2C水汽通道反演的AMVs(大气运动矢量)误差分布特征,结果显示,AMVs反演偏差存在气候带、季节以及垂直分布不均匀的时空特征.根据风随高度变化原理,推断高度指定偏高是主要误差来源.利用NCEP/FNL风场作参考,对AMVs进行高度再指定,进一步验证高度指定偏差是否为AMVs主要误差来源,结果表明,AMVs纬向风的负偏差明显减小,由-9.73 ms-1减小到-1.1 ms-1,误差标准差由10.24 ms-1降低到4.5 ms-1,改善幅度超过50%,经向风的质量也有明显改善,较好地消除了季节性误差,佐证了前述观点.初步建议了一种利用数值预报分析场作为参考将AMVs高度指定到合理高度的方法,也为AMVs产品生产者提供了一个检验算法的思路.  相似文献   
46.
以功能单体N-乙烯基甲酰胺与丙烯腈共聚,制备可转化为对重金属离子具有吸附能力的螯合物。深入计论了聚合机理,以及单体配比、单体舍量、引发剂舍量、反应温度、反应时间对聚合物转化率、特性粘数的影响。聚合动力学研究表明,该共聚几乎没有诱导期,反应初期匀速阶段较长,其转化率接近30%,自动加速不明显。运用FTIR对结构进行了表征,确立了反应的较佳条件。  相似文献   
47.
本文详细介绍了QC小组通过PDCA的三次循环来实现提高窄脉冲截尾器国产化合格率.  相似文献   
48.
针对QC-LDPC码的Tanner图中存在的短环,尤其是4环,对迭代译码性能产生不利影响的问题,寻找到一种有限域乘群构造法,该方法构造的QC-LDPC码的Tanner图中不存在任何4环。基于此方法构造的码长为3 060,码率为的(3,12)规则QC-LDPC码,选用Altera公司StratixII系列的EP2S60F484C4器件,对其实现了分层译码器硬件结构的设计。实现结果表明,在最大迭代次数为5时,时钟频率最高可达35.38 MHz,吞吐量达到92.27 Mbit·s-1。  相似文献   
49.
The present paper is devoted to determining the crack tip plasticity of a half-infinite Dugdale crack embedded in an infinite space of one-dimensional hexagonal quasicrystal. A pair of equal but opposite line loadings is assumed to be exerted on the upper and lower crack lips. By applying the Dugdale hypothesis together with the elastic results for a half-infinite crack, the extent of the plastic zone in the crack front is estimated. The normal stress outside the enlarged crack and crack surface displacements are explicitly presented, via the principle of superposition. The validity of the present solutions is discussed analytically by examining the overall equilibrium of the half-space.  相似文献   
50.
基于嵌入式技术的GPS车载终端   总被引:2,自引:0,他引:2  
本文介绍了基于嵌入式技术的GPS车载终端的设计与实现.首先分析了GPS技术原理,介绍了LPC2131单片机、MC39I和Lassen IQ模块的性能,叙述了车载终端的硬件设计思路,并给出了关键软件代码和编程思路.  相似文献   
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