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981.
The determination of xenobiotics in keratinized matrices, such as nails and hair, has received considerable attention because of the relatively long detection window for compounds. The distribution of xenobiotics in fingernails, unlike hair, was equivocal. The main aim of this study was to use follow-up surveys to measure zolpidem profiles in nails after subjects consumed a single dose of the drug. In addition, the zolpidem concentrations in nails were compared with data for different biosamples, such as hair and blood from previous work. With these preconditions, a high-performance liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of zolpidem in nails. Nails underwent alkaline hydrolysis and were extracted with diethyl ether. A Capcell Pak C18 MGII column was used to separate the target compound, and an API 4000 Qtrap mass spectrometer was used as a detector. The results for nail samples from seven subjects who had taken a single 10 mg zolpidem dose were significant: two relatively high zolpidem concentrations were observed in the long-term follow-up analysis of nails. The zolpidem concentration was less than 1.74 pg/mg and less than 3.29 pg/mg in fingernails and toenails, respectively. The subsequent peak concentration of zolpidem was observed between 10 and 15 weeks after each subject took a single dose of the drug. This result suggested that the germinal matrix area was a primary in vivo pathway for zolpidem secretion into the nail. The analysis of biosamples, such as nails, may be a useful adjunct to conventional methods of drug testing and hair analysis. Further research is needed concerning the contamination risk in analysis of nail biosamples. 相似文献
982.
利用预乳化乳液法制备了不同单体配比的聚(甲基丙烯酸甲酯-co-甲基丙烯酸-co-甲基丙烯酸羟乙酯)(P(MMA-co-MAA-co-HEMA))微凝胶分散液;采用透射电子显微镜、动态光散射仪研究了微凝胶的微观形态、粒径大小及其溶胀率;利用试管倒转法对微凝胶分散液的凝胶化相转变行为进行了研究,借助椎板流变仪考察了所形成胶态凝胶的储能模量与单体配比、微凝胶分散液浓度和温度的关系.结果表明,所制备的微凝胶的数均粒径为90 nm左右,当MMA与MAA的投料质量不变时,随着HEMA含量的增加,分散液凝胶化所需的临界最小浓度增大,临界最大pH值减小,胶态凝胶的储能模量增加.当保持单体MMA与HEMA的投料质量不变时,随着单体MAA投料质量的增多,微凝胶的数均粒径和溶胀率增大,胶态凝胶的储能模量先升高后降低;当MAA占单体总摩尔数的25%时,浓度为15 wt%的微凝胶分散液在扫描频率为100 rad/s时,胶态凝胶的储能模量最高可达2×104Pa.这类微凝胶分散液在组织工程支架材料方面有潜在的应用价值. 相似文献
983.
Wenting Han Shuzhen Liao Chonghua Zhang Huazhi Ding Zhaoyang Wu Guoli Shen Ruqin Yu 《中国化学》2013,31(8):1072-1078
A new sensitive fluorometric assay method for acetylcholinesterase (AChE) and its inhibitor was developed using a fluorescent dye, nile red (NR). Due to the fluorescence resonance energy transfer between the NR and the gold nanoparticle (AuNPs), the fluorescence was quenched. AChE can break down acetylthiocholine to produce a thiol‐bearing compound, thiocholine. In the presence of thiocholine, the nile red is replaced from the AuNPs surfaces and simultaneously transformed to a derivative of nile red. The fluorescence intensity of the derivative is much stronger than that of the native nile red with the same concentration and its maximum emission wavelength has a blue shift so that the sensor achieves a good signal‐to‐background ratio. In addition, when organophosphate pesticide (OPs) exists, the activity of AChE can be inhibited, the generation of thiocholine will be prevented and no fluorescence enhancement occurs. The results show that the method is sensitive to AChE and paraoxon with the detection limits of 0.2 mU/mL and 0.05 ng/mL, respectively. 相似文献
984.
The controlled synthesis of Mg(OH)2 nanowires and microflowers composed of nanoplates was successfully achieved by a template‐free hydrothermal synthetic method. It was found that the reaction medium played a crucial role in the morphological control of the precursor nanostructures. The high polarity of water molecules favored the polar growth of the precursor, resulting in the formation of nanowires with a diameter of 80 nm, whereas a mixed water/ethanol medium with a lower degree of polarity led to the formation of microflowers. Moreover, mesoporous MgO nanostructures could be obtained by further annealing these as‐prepared precursors in air at 500 °C for 2 h. During thermal treatment, the wire‐ and flower‐like morphologies were retained. Porosity formation was due to thermal decomposition of Mg(OH)2 and release of H2O. Both the mesoporous MgO nanowires and microflowers showed superior ability of adsorbing the organic dye methyl orange, and thus they are promising candidates for polluted water treatment. 相似文献
985.
Huiwang Wu Shucheng Liu Wenping Zhu Jianhui Jiang Guoli Shen Ruqin Yu 《Electroanalysis》2012,24(12):2365-2370
A sensitive electrochemical biosensor was developed for activity detection of histone deacetylase sirtuin2 (SIRT2) using an acetylated peptide substrate. This substrate could be recognized by anti‐acetylated peptide antibody, which could be detected using secondary antibody conjugated alkaline phosphatase which provided an amplified electrochemical signal. In the presence of SIRT2, the substrate was deacetylated, resulting in a decreased electrochemical signal that was correlated to the concentration of SIRT2. Under optimized conditions, the biosensor exhibited a wide linear range from 1 nM to 500 nM with a detection limit of 0.1 nM. The proposed biosensor was also used for detection of SIRT2 inhibitor. 相似文献
986.
Jingjing Yuan Yanping Zhu Mi Lian Qinghe Gao Meicai Liu Fengcheng Jia Anxin Wu 《Tetrahedron letters》2012,53(10):1222-1226
Eight unsymmetrical N and/or O-bridged calixarene derivatives were obtained by 1 (naphthalene-2,7-diol), 2 (bis(4-hydroxyphenyl)methanone), 3 (4,4′-methylenedianiline), 4 (3,3′-methylenedianiline), 5 (4,4′-oxydianiline) and 6 (4,4′-(perfluoropropane-2,2-diyl)dianiline) reacting with fragment a (4,4′-bis(dichloro-s-triazinyloxy)propane-2,2-diyldibenzene) and b (N,N′-bis(dichloro-s-triazinyl)-4,4′-methylenedianiline) under very mild reaction conditions via efficient fragment coupling strategy. We also obtained the crystal structure of 1a (tetraoxocalix[2](propane-2,2-diyldibenzene,naphthalene)[2]triazine) which can form a molecular capsule by two dimers with C–H?N and C–H?O quadruple hydrogen bonds, and it has the encapsulation ability toward solvent molecules. 相似文献
987.
设计合成了5种未见文献报道的5,10,15,20-四{对[3,5-二-(烷氧基)苯甲酰胺基]苯基}卟啉及其锌金属配合物,并用IR,UV-Vis,1H NMR,元素分析以及XPS对其组成和结构进行了表征,研究了这10种酰胺基系列卟啉化合物的拉曼光谱和荧光光谱的变化.结果显示链长对荧光和拉曼光谱没有明显影响,其取代基效应基本相同,配体的荧光强度强于锌配合物的荧光强度.在拉曼光谱中,由于卟啉分子平面的对称性由D2h变为D4h群及其锌离子d轨道的电子效应,卟啉配体和锌配合物之间的拉曼光谱有很大差别. 相似文献
988.
综述了环糊精(包括α-环糊精,β-环糊精和γ-环糊精)衍生物在金属催化有机合成中的应用,主要包括其作为金属离子配体、金属纳米粒子稳定剂和反相相转移催化剂在氧化、水解、还原、偶联等金属催化反应中的应用.其中环糊精衍生物作为金属离子配体应用最广,由于环糊精部分与底物形成包结络合物,拉近了底物和具有催化活性的金属离子的距离,并固定了底物的反应部位,往往可以显著提高催化反应的反应速率,增强反应的区域选择性和对映选择性. 相似文献
989.
990.
以乙酰乙酸乙酯、4-羟基苯甲醛、碳酸氢铵和二溴烷烃为原料,经两步反应合成溴烷氧基1,4-二氢吡啶;再将其与5-对羟基苯基-10,15,20-三苯基卟啉缩合,得到了12种新型的卟啉-二氢吡啶及其金属锌配合物,结构通过NMR,IR和HRMS进行详细表征.研究中测试了这些复杂的卟啉-二氢吡啶化合物对金黄色葡萄球菌(Staphylococcus aureus,ATCC 25923)和大肠杆菌(Escherichia coli,ATCC 25922)的抑菌活性,实验结果显示这12种化合物都有很好的抑菌活性,其中对金黄色葡萄球菌抑菌效果较好,且卟啉-二氢吡啶二元化合物的抑菌效果优于两种单体. 相似文献