出生缺陷高发区人发元素含量分析研究

目的:寻找出生缺陷高发区病人体内含量异常的元素,为出生缺陷的干预和治疗提供理论依据。方法:在病区分别采集有出生缺陷儿童和健康儿童头发样品,经预处理后,采用ICP-电感耦合等离子发射光谱法,对16种元素进行了测定,所得数据采用SPSS 10.0进行非参数检验和多元回归分析。结果:与健康儿童头发样品相比,患儿发中Mo,Zn,Sr,Fe,Mg,Ca等含量显著偏低,V偏高;以病情为因变量,发中16种元素含量为自变量经逐步回归分析,有Mo,Zn,Ni等进入方程。提示该区病人体内Mo,Zn等含量低、Ni含量高与病情有关。结论:Mo,Zn等在人体内的缺乏可能是出生缺陷发生的重要因素,Sr,K,Cu,Sn,Mg,Se,Fe,Ca等含量偏低及V含量偏高可能与Mo,Zn,Ni等共同起到协同致病的作用。     

柴达木唐古特白刺色素中矿物质元素分析

对唐古特白刺色素的矿物质元素进行了分析。结果表明,在色素中Na、K、Ca含量高,这与白刺生长在盐碱地有关;Fe、Zn、Cu、Mn、Se等必需微量元素含量丰富;有害元素含量低。为唐古特白刺色素在食品和饮料中的应用提供了基础数据。     

无锡出生缺陷高发区地理环境化学元素的特征

为了解出生缺陷高发区地理环境因素的异常特征,给出生缺陷的预防性干预提供科学依据,按照"无锡市出生缺陷病例/育龄妇女人口图"确定无锡市惠山区和锡山区为出生缺陷高发区,宜兴市为对照区。采用电感耦合等离子体原子发射光谱仪对采集的土壤、水、粮食、头发等515个样品进行了砷等17种元素的测定,利用SPSS 11.0软件对数据进行了非参数检验和多元线性回归分析。结果表明,无锡与山西出生缺陷高发区患者发样中钒含量均显著偏高;两个地区得到的回归方程中存在很多重叠元素,尤其是镁和钼几乎存在于每个方程中。可见钒含量显著偏高可能是导致出生缺陷发生的重要因素;镁和钼含量异常以及它们之间或与其它元素之间存在的协同或拮抗作用可能对出生缺陷的发生起到关键作用。     

电感耦合等离子体质谱法测定香薷中无机元素含量的研究

采用电感耦合等离子体质谱（ICP—MS）法对香薷中的Ca、Mg、Cu、Zn、Fe、Mn、Co、Ni、Se等18种无机元素进行了分析测定。该方法的回收率在84．62％～113．16％,具有良好的准确度和精密度,完全可以满足香薷样品中无机元素测定要求。研究结果表明：香薷中Ca和Mg两种必须的常量元素的含量特别高,微量元素Cu、Zn、Fe、Mn、Co、Ni、Se含量丰富。此结果可为探讨香薷中元素含量与其药效相关性提供科学依据。     

人参与微量元素

概述了人参的微量元素研究近况，人参中含有Li、Na、K等44种无机元素，特别是含有14种人体必需微量元素中的Fe、Zn、Se等13种，人参的药理活动与它的Ge含量有关。其含量比其它中药部高，吉林人参各部位Se总平均与果肉中含量分别为富Se抗菌中药黄芪的1.2和2.4倍，大量研究结果提示，人参类补益药的广泛临床功用与微量元素的作用密切相关。     

金银花茶中8种微量元素溶出特性研究

目的 探究金银花茶样品中8种微量元素的溶出特性。方法 基于电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS),测定样品中Na、Ca、Mg、Mn、Fe、Zn、Cu、Se 8种微量元素含量,并分别研究了浸泡时间、浸泡次数及浸泡温度与元素溶出特性之间的关系。结果 结果表明,金银花茶中微量元素含量丰富,8种元素含量由高到低的顺序为：Ca>Mg> Fe>Na>Mn> Zn>Cu>Se。各元素溶出量随浸泡时间延长而升高,其中Fe溶出率最低,表明Fe最难溶出。除Na和Se以外,各元素溶出量随浸泡次数增加而降低,随浸泡温度升高而升高;Na的溶出量随浸泡次数增加呈先降低后升高的趋势,而Se的溶出量随浸泡次数增加而降低;Na和Se的溶出量均随浸泡温度升高呈先升高再降低的趋势。各元素溶出量与浸泡时间、浸泡次数及浸泡温度之间的关系均可通过建立不同类型的数学模型进行描述。结论 从保健茶饮的功能性和风味角度考虑,金银花茶冲泡应选用100℃的水温,且冲泡次数应不超过4次。     

传统藏药材高原香薷的矿质元素分析

对传统藏药材香薷中高原香薷种的17种微量元素进行了分析。结果表明,在高原香薷中人体必需微量元素Cu、Zn、Fe、Mn、Co、Ni、Se等含量较高,尤其以Cu、Fe、Mn元素的含量为高。Na、Ca等宏量元素含量亦较高。     

豫东地区煤中有害痕量元素的分布研究

以豫东地区主要煤层为研究对象,初步研究和分析了豫东地区4个矿区煤样中As、Cr、Pb、Cu、Mn、Se等14个痕量元素含量,并结合现有资料和文献给出了其在煤中的赋存状态。结果表明,Pb、Hg、Cr、Mo、Mn和Cu含量的平均值是美国煤的1.5~5倍,除Hg外,其它的元素含量均低于全国土壤中含量的平均值;Se高于全国平均值而仍低于美国平均值,且远高于全国土壤的平均值;Co的含量比全国和美国的平均值都高,但仍低于全国土壤的平均值;Th的平均值接近于美国平均值,几乎分别占全国平均值和土壤平均值的二分之一和四分之一;所有痕量元素都比世界范围的值低;豫东地区原煤中As和P的含量低,基本属于一级含As煤和特低P煤层;在原煤的利用中应关注这些痕量元素所导致的污染。为豫东地区的综合开发和洁净煤炭利用提供参考资料。     

温莪术中As、Se含量的测定

对温莪术中As、Se两种元素的含量采用HG-ICP-AES法进行了测定分析。结果表明,温莪术全草中具有较高的Se元素含量和很低的As元素含量,从As和Se两元素含量的角度可见,温莪术具有一定的药用价值。并将温莪术经超声煎煮不同时间后得到的药液、药渣进行对比,发现As含量均很低,而Se含量在药渣中显著高于药液。     

ICP-MS法分析白花蛇舌草中16种无机元素初级形态

应用电感耦合等离子体质谱技术(ICP-MS),分析了白花蛇舌中16种无机元素的初级形态;并研究了微波辅助萃取、超声辅助萃取、恒温水浴萃取三种萃取方式对其溶出特性的影响。结果显示:白花蛇舌草中含有丰富的无机元素,这可能促进其有效成分作用的发挥。除Cu、Se外,其它元素的微波萃取的萃取效率最高;Mg、K、Ca、Mn、Ni、Se、Ba的溶解态含量较高,其他元素主要以悬浮态的形式存在于溶液中。     

Enhanced mechanical and shape memory properties of polyurethane block copolymers chain-extended by ethylene diamine

Effect on shape memory and mechanical properties of polyurethane (PU) copolymers by changing the chain extender from 1,4-butanediol (BD) to ethylenediamine (ED) was investigated. PU copolymers composed of the different ratio of hard and soft segment were prepared and characterized by IR, DSC, XRD, and UTM. Glass transition temperature of PU increased to room temperature range by adopting ED as a chain extender. The XRD peak pattern changed with hard segment content. ED type PU achieved the high mechanical properties at lower hard segment content than BD type PU. Especially, strain at break of ED type significantly improved compared to BD type. Shape recovery rates were similar for both types of PU, but ED type showed better shape retention rate than BD type. The reason for the differences between two types of PU is discussed in this paper.     

Microstructure and properties of polyurethanes derived from castor oil

The goal of this work was the synthesis of novel segmented polyurethanes with a high percentage of components derived from renewable sources. The soft segment was a polyol derived from castor oil and the hard segment structure was varied by means of different chain extenders, petrochemical-based 1,4-butanediol (BD) and corn sugar-based 1,3-propanediol (PD). The synthesis was carried out in bulk and without catalyst via a two-step polymerization varying hard segment ratio. Physico-chemical, mechanical and morphological characterization was performed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), atomic force microscopy (AFM), mechanical testing and termogravimetric analysis (TGA). Properties have been discussed from the viewpoint of hard/soft microdomain phase separation and also the hard segment nature and formed structure. An increase in hard segment content was accompanied by an increase in hard domain order, crystallinity, and stiffness. The hard segment structures, in addition to the elastic nature of soft segment, provide enough physical crosslink sites to impart properties ranging from elastomeric to rigid behaviour with the increase of hard segment content. Polyurethanes synthesized from bio-based chain extender showed a slightly lower crystallinity in the hard segment structure than that synthesized from BD as the chain extender. This lower crystallinity avoids strength concentrations at the soft/crystalline hard segment interface, thus improving the mechanical properties at high hard segment content. The slightly higher thermal stability observed for BD based polyurethanes is related with their more packed structures and crystallinity observed in the hard segment structure.     

抑制剂BD2对PKA与PKC βII的抑制选择性研究

蛋白激酶A (PKA)和蛋白激酶C (PKC)的过度表达导致细胞生长分化异常, 是治疗肿瘤的潜在靶点. 抑制剂BD2对PKA和PKC抑制作用存在高选择性. 为了探讨BD2高选择性机制, 本工作以PKA与BD2复合物的晶体结构为模板, 通过同源模建结合分子对接的方法构建PKC βII与BD2复合物的结构, 并对PKA-BD2复合物和PKC-BD2复合物进行了2.5 ns的分子动力学模拟, 运用MM-GBSA方法计算了结合自由能, 通过能量分解的方法考察PKA和PKC的主要残基与BD2之间的相互作用和识别机制. 结合能分析结果很好地描述了BD2对PKA抑制活性比其对PKC抑制活性高这一实验现象. 氢键分析和能量分解结果共同说明了BD2的B环和酰胺链部分与PKA和PKC中相应位点的残基之间的相互作用存在差异, 这是BD2存在选择性的内在因素. BD2高选择性作用机制的阐明为进一步基于结构的balanol类抑制剂的结构设计和优化提供了合理的指导.     

Copolymerization of butadiene and styrene with a gadolinium tricarboxylate catalyst

Homo- and copolymerizations of butadiene (BD) and styrene (St) were carried out by gadolinium catalysts having various tricarboxylate ligands [Gd(OCOR)₃: R = CH₃, CH₂Cl, CHCl₂, CCl₃, and CF₃], to investigate the effects of ligands and discuss the cis polymerization mechanism. Polymerization of BD with Gd(OCOR)₃—(i—Bu)₃Al—Et₂AlCl catalysts was carried out in hexane at 50°C. By each catalyst, poly(BD) having a high cis content (cis = 97–99%) in 22–85% yields for 2–24 h were obtained. The ligands with low pKa values increased the polymerization activity as follows: R of Gd(OCOR)₃: CF₃ > CCl₃ > CHCl₂ > CH₂Cl ～ CH₃. On the other hand, in the polymerization of St or copolymerization of BD and St under similar conditions, the highest activity was attained by a Gd(OCOCCI₃)₃- based catalyst. The difference in the optimum ligand among the homo- and copolymerization of BD and St was discussed on the basis of energy levels of the catalysts. In the copolymers of BD and St, the cis-1,4 content of the BD unit decreased with increasing St content. Furthermore, according to the diad analysis of copolymers (St content ～ 14.5 mol %) by ¹³C NMR spectroscopy, the low cis value of the BD unit was observed in the St-BD diad (cis/trans/vinyl = 24/53/23), while the high cis value of the BD unit remained in the BD-BD diad (cis/trans/vinyl = 89/10/1). These results suggest that the terminal BD unit is controlled by the cis configuration by the coordination between the penultimate cis vinylene unit and the gadolinium metal catalyst, whereas the presence of the penultimate St unit interferes with cis polymerization of the terminal BD unit. The difference in the coordination mechanism in the course of polymerization between rare earth metal and transition metal catalysts such as the Ni(acac)₂ and Co(acac)₃-based catalyst was also discussed. © 1995 John Wiley & Sons, Inc.     

Influence of Reaction Conditions on Main and Side Reactions During the Transesterification of Dimethyl Terephthalate with 1, 4-Butanediol

The transesterification of dimethyl terephthalate (DMT) with 1, 4-butane-diol (BD) has been studied by measuring the amount of methanol and tetrahydrofuran formed during the reaction. Investigation of various catalyst systems revealed that titanium isopropoxide was a better catalyst than conventional transesterification catalysts such as manganese and cobalt acetates. Increases in the temperature, BD/DMT ratio, and catalyst concentration led to higher production of methanol. Increases in temperature and BD/DMT ratio raised THF production, but increased catalyst concentration decreased the amount of THF produced. The relative importance of BD dehydration and cyclization of 4-hydroxy-butyl ester end groups in the formation of THF was also studied.     

不同产地川党参微量元素的聚类分析

用原子吸收火焰法（FAAS）测定了28个不同产地和采收时间的川党参的7种微量元素,用DPS8．5版软件对测试结果进行聚类分析。结果显示,除重庆武隆县以外的川党参都非常接近,该法可简便地鉴别不同产地和采收时间的川党参真伪。     

Thermal and pyrolysis studies of copolyesters

Random copolyesters of dimethyl terephthalate (DMT), ethylene glycol (EG), and butane-1,4-diol (BD) and the homopolyesters poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) have been subjected to degradation and pyrolysis studies. Differential thermal analysis (DTA) showed that the decomposition temperature is dependent on the percentage of EG and BD present in the copolyesters. Thermal volatilization analysis (TVA) also showed that the decomposition temperature is dependent on the percentage of EG and BD present in the copolyesters. The trend for the decomposition temperatures obtained from TVA studies for these copolyesters is similar to such other thermal properties as melting temperature T_m, ΔH_f, ΔH_c, etc. The subambient thermal volatilization analysis (SATVA) curves obtained for these polymers are also presented. The SATVA curve is the fingerprint of the total volatile products formed during the degradation in high vacuum. The isothermal pyrolysis of these materials was carried out in high vacuum at 450°C. The products formed were separated in a gas chromatograph and were subsequently identified in a mass spectrometer. The major pyrolysis products from PBT were butadiene and tetrahydrofuran, whereas those from PET were ethylene and acetaldehyde. The ratio of acetaldehyde to ethylene increases with the EG content in the copolyester, suggesting a different decomposition mechanism compared to the decomposition mechanism of PBT and PET.     

Detection of air pollution sources in israel by isotope-induced XRF

Aerosol samples from urban, industrial and traffic areas were collected and analyzed for various elements. The correlation between the multielement content of the samples and their sources was studied. It was found necessary to anlayze samples before and after ashing because, while ashing improves the peak-to-background ratio, volatile elements may be lost. Samples collected at heights of 1.5 and 15 m were found to have the same elemental composition. Samples collected on consecutive filters showed sharp elemental fractionation An example of source identification is given for a high traffic area as compared with an area in which a large bromine plant is located. In both cases different Pb∶Br ratios were observed, with high bromine concentration in the latter. The analytical method used was based on the detection of characteristic K and L X-rays induced by a²⁴¹Am-I source-target assembly.     

High efficiency synthesis of octavinylsilsesquioxanes and its high performance hybrids based on bismaleimide‐triazine resin

An improved method is developed to synthesize octavinylsilsesquioxanes (VPOSS) with shorter time and higher yield, and then VPOSS is used to prepare new hybrids based on bismaleimide‐triazine (BD/CE) resin, coded as VPOSS/BD/CE. The effect of the content of VPOSS on the key properties including curing behavior, thermal, mechanical, and dielectric properties as well as water resistance of VPOSS/BD/CE hybrids were systematically discussed. Compared with BD/CE resin, hybrids show similar curing behavior but different chemical structures and thus macro‐performance. These key properties of hybrids are dependent on the content of VPOSS, all hybrids show significantly improved dielectric properties, water resistance, and dimensional stability; moreover, the hybrids with suitable content of VPOSS have bigger impact strengths. Specifically, with the addition of 7 wt% VPOSS to BD/CE resin, the dielectric constant decreases from 3.7 to 3.2, the dielectric loss decreases 55%, and the coefficient of thermal expansion reduces 23%; moreover, the glass transition temperature and initial decomposition temperature increase about 15°C. The attractive integrated properties suggest that VPOSS/BD/CE hybrids have great potential to be used as structural and functional materials for many cutting‐edge fields. Copyright © 2011 John Wiley & Sons, Ltd.     

A new method for the quantitation of aflatoxin M1 in urine by high performance liquid chromatography and its application to the etiologic study of hepatoma

A high performance liquid chromatographic (HPLC) method for the analysis of aflatoxin M1 (AFM1) in urine is described. Urine samples were treated with saturated lead acetate and AFM1 was extracted with chloroform. After washing with water to remove impurities the compound was derivatized with trifluoroacetic acid and the AFM1 derivative was analyzed quantitatively by HPLC. The sample pretreatment is simple and more selective. A good line correlation between AFM1 peak height and its concentration was obtained when AFM1 content was in the range of 50-400 pg. The ratio of recovery was 87.42%. Sensitivity is 0.01 ppb. The method is applicable to trace analysis. Results in urine of residents who live in the high/low liver cancer incidence area in Fushui county were the same as that of previous epidemiological investigation.