氯化钙/水-醇溶液稀释热

电解质溶液稀释热是溶液的重要热性质之一．由它可计算不同浓度下电解质的溶解热、表现相对摩尔焓、溶液中反应热和化合物生成热等．在电解质溶液理论研究中，稀释热也是重要的基础数据．由稀释热可推算溶液中组分的活度系数、渗透系数、相对偏摩尔焓及表观摩尔热容等[1-3]．在化工生产中，稀释热是化工过程能量计算不可缺少的数据．电解质水溶液稀释热已有不少研究[2，4]．但电解质混合溶剂体系稀释热报导甚少．随着加盐精馏技术、海水淡化技术等研究的进展，急需这方面数据．本文作者已报告了CaCl2／C2H5OH－H2O体系[5]和CaCl2／n－C…     

超声引导椎旁神经阻滞治疗带状疱疹后遗神经痛的疗效及可行性分析

本文对超声引导椎旁神经阻滞治疗带状疱疹后遗神经痛（post-herpetic neuralgia，PHN）的疗效及可行性进行了分析。研究对象为2015年12月~2017年12月于我院就诊的94例PHN患者，按就诊顺序随机均分为两组，对照组给予普瑞巴林常规治疗，观察组在此基础上联合超声引导椎旁神经阻滞治疗，连续治疗4周。本文比较了治疗前、治疗1周、2周、4周后的匹兹堡睡眠质量指数（PSQI）评分、疼痛视觉模拟（VAS）评分，并评价了治疗后的综合疗效，记录了治疗期间发生不良反应情况。结果显示，较治疗前，治疗1周、2周、4周后两组VAS评分均逐渐降低，且观察组治疗后各时间点的VAS评分显著低于对照组，差异具有统计学意义（P<0.05）；较治疗前，两组治疗1周、2周、4周后PSQI评分均逐渐降低，且观察组治疗后各时间点的PSQI评分显著低于对照组，差异具有统计学意义（P<0.05）；观察组治疗总有效率为89.36%，对照组为78.72%，观察组显著高于对照组，差异具有统计学意义（P<0.05）；两组治疗期间各项不良反应发生率差异无统计学意义（P>0.05）。本文证实了超声引导椎旁神经阻滞治疗PHN能显著改善患者神经疼痛症状，提升睡眠质量，同时具有安全性保障。     

部份互溶体系4-甲基-2-戊醇和水的过量焓研究

使用LKB-2107型流动式微量量热计测定了4-甲基-2-戊醇和水这一部份互溶体系在293.15 K、298.15 K和303.15 K的常压过量焓。测量结果用Redlich-Kister方程作了关联。另外,还用该体系富醇区的过量焓数据拟合NRTL模型的参数与温度关系,推算较高温度下该体系的常压汽液平衡(VLE)组成及泡点。推算值与文献值是接近的。实验试剂4-甲基-2-戊醇由粗品经三次蒸馏提纯,沸点为404.95 K,折光率n_D~(20)1.4113,密度d~(20)0.8067 g cm~(-3),与文献值一致。无水乙醇、尿素均为分析纯。液体试剂在使用前均     

Chiral separation and molecular simulation study of six antihistamine agents on a coated cellulose tri-(3,5-dimethylphenycarbamate) column (Chiralcel OD-RH) and its recognition mechanisms

Enantiomeric separation of six antihistamine agents was first systematically investigated on a cellulose-based chiral stationary phase (CSP), that is, cellulose tris-(3,5-dimethyl phenyl carbamate) (Chiralcel OD-RH), under the reversed-phase mode. Orphenadrine, meclizine, terfenadine, dioxopromethazine, and carbinoxamine enantiomers were completely separated under the optimized mobile phase conditions with resolutions of 5.02, 1.93, 1.68, 1.67, and 1.54, respectively. Mequitazine was partially separated with a resolution of 0.77. The influences of type and concentration of buffer salt, the pH of buffer solution, and the type and ratio of organic modifier on the chiral separation were evaluated and optimized. For a better insight into the enantiorecognition mechanisms, molecular docking was carried out via the Autodock software. The lowest binding energy and the optimal conformations of the analytes/CSP complexes were supplied, and the mechanisms of chiral recognition were determined. According to the results, the key interactions for the chiral recognition of these six analytes on CDMPC were π–π interactions, hydrophobic interactions, hydrogen bond interactions, and some special interactions.     

A New Arugosin from Talaromyces flavus

Chemistry of Natural Compounds - Arugosin R (1), a new arugosin type metabolite, was isolated from Talaromyces flavus. Its structure was characterized by detailed analyses of IR, MS, 1D, and 2D NMR...     

Triterpenoids with Cytotoxicity from Abelia engleriana

Chemistry of Natural Compounds -     

A new near-infrared fluorescent chemodosimeter for discrimination of sulfide from disulfide

Research on Chemical Intermediates - A new near-infrared fluorescent “turn-on” chemodosimeter (probe 1) based on dicyanomethylene-4H-chromene fluorophore for sulfide was developed....     

Analytical vectorial structure of Hermite-cosine-Gaussian beam in the far field

Based on the vector angular spectrum representation of electromagnetic beams and the method of stationary phase, the vectorial structure of a Hermite-cosine-Gaussian (HcosG) beam in the far field is derived in analytical form. Energy flux distributions for the TE term, TM term and the whole beam are represented. The vectorial structures of HcosG beams with different Hermite models are depicted. The effects of cosine displacement parameters on the vectorial structure are also demonstrated. The results may provide a flexible approach to manipulate HcosG beams in free space.     

Propagation properties of Lorentz beam in uniaxial crystals orthogonal to the optical axis

The properties of Lorentz beams propagating in uniaxial crystals orthogonal to the optical axis are studied. The diffraction field components and effective beam sizes of the Lorentz beams are derived in analytical forms. Numerical results show that, upon propagating in uniaxial crystals, a Lorentz beam loses its initial Lorentz type distribution. Also, after propagating for sufficient distances, the transverse components would finally convert into a specific four-petal profile with an axial shadow, which may find applications in the optical trapping of particles. It also shows that the Lorentz beam parameters w_0x, w_0y and the ratios of refractive indices have strong influences on the diffraction field components and on the effective beam sizes when propagating in uniaxial crystals.     

镁合金空心螺钉内固定治疗股骨颈骨折的有限元分析研究

利用有限元分析方法探究镁合金空心螺钉内固定治疗股骨颈骨折的生物力学特性, 旨在为临床治疗股骨颈骨折提供一种新的思路. 选取一例青年健康志愿者的下肢CT数据建立股骨三维模型, 在Mimics插件3-matic中建立股骨网格并赋予网格材料属性, 利用Solidworks 17.0软件建立空心螺钉模型, 将上述2个三维模型导入Workbench 2020软件中, 分别赋予空心螺钉镁合金、钛合金材料属性, 进行对比分析, 记录股骨及空心螺钉的峰值、应力分布值和股骨位移. 结果表明, 钛合金螺钉内固定模型最大应力为357.27MPa, 最大位移为0.034mm; 镁合金螺钉内固定模型最大应力为311.27MPa, 最大位移为0.034mm; 2组不同材料的空心钉结果数值差异不大. 研究表明镁合金空心螺钉和传统钛合金空心螺钉力学性能相似, 且镁合金更加亲和人体, 在临床方面可以镁合金空心螺钉代替钛合金空心螺钉治疗股骨颈骨折.