L-赖氨酸锌细胞生物学和生理学实验研究

研究了L-赖氨酸锌对健康大鼠血液及骨髓中细胞的影响,并与对照组进行了比较结果表明,本品对健康鼠血液中红细胞、血小板、淋巴细胞、中性白细胞和单核细胞及骨髓多染红细胞中的微核数等均无显著性影响．另外大鼠伤寒沙门氏菌的致突变实验显示L-赖氨酸锌未引起大鼠伤寒沙门氏组氨酸缺陷型变异菌株的回复突变．而健康小儿血液各项生化指标的变化,揭示本品可显著提高血液中碱性磷酸酶和红细胞水平．对白细胞的增殖有促进作用．但对乳酸脱氢酶、谷丙转氨酶等无显著性影响．     

胃癌病人发微量元素测定及其临床意义

对４３例胃癌病人测定了发中Ｚｎ、Ｃｕ、Ｆｅ、Ｍｎ、Ｃａ、Ｍｇ六种元素，结果：胃癌组发中Ｃｕ、Ｆｅｘ±ＳＤ值较健康对照组升高，Ｐ＜０．０５，有显著性差异．Ｚｎ、Ｃａ、Ｍｇｘ±ＳＤ值较健康组降低，Ｐ＜０．０５、＜０．０１、＜０．０１，差异有显著性和高度显著性．ＭＵｘ±ＳＤ值与健康对照组近似，Ｐ＞０．０５，差异无显著性．胃癌组Ｚｎ／Ｃｕ比值较健康对照组降低，Ｐ＜０．０１，差异高度显著性；胃癌组Ｚｎ／Ｆｅ比值与健康组近似，Ｐ＞０．０５，差异无显著性．Ｆｅ升高，Ｍｎ、Ｚｎ降低是胃癌的危险因素，Ｍｎ有抗癌抑癌作用，Ｆｅ、具有强烈催化自由基及过氧化反应的能力．发中微量元素测定可作为临床胃癌病人辅助诊断参考．     

仪器信息网发布“食品检测”频道

食品是人类赖以生存和发展的物质基础,食品质量与安全关系到人类健康、社会稳定和经济发展．近年来,食品质量及安全问题越来越受到人们的关注,开展食品检测工作的实验室或机构也越来越多．     

仪器信息网发布"食品检测"频道

食品是人类赖以生存和发展的物质基础,食品质量与安全关系到人类健康、社会稳定和经济发展．近年来,食品质量及安全问题越来越受到人们的关注,开展食品检测工作的实验室或机构也越来越多．     

妊娠与微量元素食疗的关系探讨

应用原子吸收分光光度法测定了2300例健康孕妇及150例未受孕健康妇女发中锌、铜、铁、钙的含量。结果表明,妊娠妇女微量元素缺乏率为：铁63．54％、锌44．26％、钙29．17％。研究揭示,微量元素与妊娠有非常密切的关系,应通过食疗调整,使孕妇体内微量元素维持在正常水平,保证孕妇的身体健康和胎儿的正常生长发育。     

营养·微量元素与人体健康

与人体健康有关的四个基本条件是： １ ． 精神（ 心理） 因素; ２ ． 营养状况; ３ ． 运动水平;４ ． 医疗条件。在营养方面, 平衡摄取六大营养要素是保证健康的物质基础。目前营养中最缺乏又不易满足的是微量元素。而微量元素是贯穿六大营养要素的经纬线, 是人体健康的守护神。本文简述了微量元素的功能、作用, 同时就２１ 世纪的平衡营养食品, 以及如何了解自身微量元素状况, 提出了看法。     

碳纳米管的细胞毒性

随着碳纳米管（CNTs）的大量生产和应用,它们对环境和人类健康可能带来不利的影响．因此,CNTs的生物效应和安全性研究引起科学家和各国政府的高度重视．扼要介绍了CNTs的体外毒性研究的主要结果,重点讨论了影响CNTs细胞毒性的诸多因素,包括CNTs的种类、所含杂质、CNTs的长度、直径和长径比、CNTs水溶性修饰以及细胞存活率的测定方法．然而,迄今CNTs细胞毒性研究取得的实验结果缺少可比性,分歧也屡见不鲜．为了更准确地评估CNTs对人类健康的潜在风险,我们认为细胞毒性检测中应该充分注意CNTs的化学修饰以及CNTs的定量表征等问题,尤为重要的是要加强CNTs细胞毒性的物理化学机制研究,逐步形成具有纳米毒理学自身特点的毒性检测方法和评估标准．     

老年痴呆症患者头发中微量元素含量变化及其临床意义

应用火焰原子吸收分光光度法测定了30例老年痴呆症患者及34例健康老人发中Zn、Cu、Fe、Ca、Pb、Cd的含量。结果表明,老年痴呆症组发Zn、Fe、Ca显著低于健康组（P＜0．01）,Pb、Cd显著高于健康组（P＜0．01）,且Cd/Zn比值显著高于健康组,有非常显著的差异（P＜0．001）。结果提示,老年痴呆症的发生可能与Zn、Ca、Pb、Cd等微量元素的含量水平异常有关,Cd/Zn比值升高可能是老年痴呆症发生的危险因素之一。     

三试剂自动分析法测定血清总铁结合力：Nitro—PAPS直接光度法

为建立简便、灵敏的三试剂自动化分析法测定血清总铁结合力（TIBC）,在表面活性剂存在下,用2-（5-硝基-2-吡啶偶氮）-5-[N-正丙基-N-（3-磺酸丙基）氨基]苯酚二钠（Nitro—PAPS）为显色剂测定了血清TIBC。结果表明,该法线性范围0～195μmol／L,平均回收率为100．7％,批内变异系数（CV）和批间变异系数分别为0．019、0．032;与临床检验操作规程推荐的方法比较具有良好的相关性,线性回归方程和相关系数分别为Y=1．0021x＋1．2100,r=0．9798;78例健康男性血清TIBC含量（x±2s）为46．8—76．1μmol／L,75例健康女性为52．8—77．6μmol／L。方法简便、灵敏可靠,适合临床应用。     

妊娠糖尿病与非妊娠糖尿病患者头发微量元素含量分析

采用高频等离子体发射光谱法测定了妊娠糖尿病患者、非妊娠糖尿病患者以及相应对照组的头发微量元素锌、铁、铜、锰、锶、镁和常量元素钙的含量。56例健康妊娠妇女的发锌含量为（139．9±31.5）×10－6，而11例妊娠糖尿病妇女为（114．3±29．4）×10－6，两者比较差异有显著性，（P＜0．05），其它元素铁、铜、锰、锶、镁和钙不存在显著性差异。而45例非妊娠糖尿病女性与33名健康非妊娠女性的头发微量元素含量比较表明：两者锌含量不存在显著性差异，但糖尿病组铜显著低于健康对照组（P＜0．05），分别为（6．32±2．31）×10－6和（9．05±16．50）×10－6，糖尿病组铁含量（21．5±11．7）×10－6亦显著低于健康对照组（26．9±10．7）×10－6，其余元素无显著性差异。前后两组实验结果表明妊娠糖尿病患者与非妊娠糖尿病患者的微量元素代谢状况并不相同，妊娠糖尿病患者的锌缺乏状态值得引起注意。     

Graft Copolymerization of Acrylamide on Swollen poly (Ethylene Terephthalate) Fibers Using Cerium Ammonium Nitrate Initiator

Abstract

In this study the graft copolymerization of acrylamide (AAm) on swollen poly(ethylene terephthalate) (PET) fibers using cerium ammonium nitrate (CeAN) initiator was investigated. Five organic solvents, dimethylsulfoxide (DMSO), morpholine, acetic acid (HAc), n-butanol, and 1,2-dichloroethane (DCE), were used as swelling agents. DMSO was found to be the most suitable swelling agent. Solvent diffusion into the fibers was observed to increase with treatment time and temperature. The optimum graft yield was obtained when fibers were grafted after having been swollen in DMSO for a period of 1 hour at 140°C. Variation of graft yield with polymerization time and temperature, and monomer, initiator, and acid concentrations were investigated. Graft yields were observed to increase initially with polymerization time, then to level off, and were found to increase up to a certain monomer and Ce⁴⁺ concentration, then to decrease slightly. The effect of grafting on such fiber properties as diameter, viscosity, and moisture gain were also investigated.     

Synthesis and Characterization of Bagasse Poly(methyl methacrylate) Graft Copolymer

Summary: Graft copolymerization of methyl methacrylate (MMA) was carried out on bagasse fibers in an aqueous medium using ceric ammonium nitrate (CAN) as initiator under a neutral atmosphere. In order to obtain the optimum condition for graft copolymerization, the effects of initiator concentration, temperature, time of reaction, and monomer concentration were studied. The maximum grafting percent was found to be 122%. The bagasse grafted poly(methyl methacrylate) was characterized by FTIR and its thermal behavior was characterized by TGA.     

Grafting of Acrylamide On 1, 1, 2, 2-Tetra-Chloroethane Preswelled Polyethylene Terephthalate) Films Using Azobisisobutyronitrile Initiator

Abstract

Graft polymerization of acrylamide (AAm) on 1, 1, 2, 2 tetrachloro-ethane (TCE) preswelled poly(ethylene terephthalate) (PET) films were performed with chemical initiation method using asobisiso-butyronitrile (AIBN) initiator. Temperature was found to have a greater effect on the swelling then the swelling time. Variation of the graft yield with polymerization temperature, time, AIBN concentration, AAm concentration, AIBN and AAm inclusion times were investigated. The optimum temperature for grafting was found to be 70°CC. The graft yield was observed to increase with polymerization time, AAm concentration, initiator and monomer diffusion time up to a saturation graft yield and then leveled off. An increase in AIBN concentration first enhanced the percent grafting then showed a decrease. The addition of some salts (Ni²⁺, Cr³⁺, Co²⁺, Cu²⁺) on the rate of grafting was also investigated. From the temperature dependence of the initial rate of grafting, the overall activation energy was found to be 4. 1 kcal/mol and relevant rate equation have been derived. The effect of grafting on film propities, such as water absorption capacity, intrinsic viscosity were determined. Grafted films were characterized by FTIR spectros-copy and scanning electron microscopy (SEM).     

WATER-SOLUBLE AMPHOLYTIC GRAFTED POLYSACCHARIDES. 1. GRAFTING OF THE ZWITTERIONIC MONOMER 2-(2-METHACRYLO-ETHYLDIMETHYLAMMONIO) ETHANOATE ONTO HYDROXYETHYL CELLULOSE

Novel ampholytic grafted polysaccharides were prepared by grafting the Zwitterionic monomer 2-(2-methacryloethyldimeth-ylammonio) ethanoate onto hydroxyethyl cellulose. Ethylenediamine tetraacetic acid was used in combination with ceric ammonium nitrate as the redox initiator. The effects of various factors such as initiator amount, monomer concentration, reaction temperature and time on the grafting were studied and the optimum reaction conditions to obtain maximum degree of grafting were found. The resulted graft copolymer was characterized by IR and thermal analyses.     

Graft Copolymerization of Methyl Methacrylate on Potato Starch Using Potassium Trioxalatomanganate,K3[Mn(C2O4)3], as Initiator

Graft copolymerization of methyl methacrylate on potato starch was carried out in methanol-water medium at 35°C in the dark using potassium trioxalatomanganate, K₃[Mn(C₂O₄)₃], as initiator. The effect of different methanol-water ratios (v/v), the temperature of polymerization, the initiator concentration, the monomer concentration, the starch content, and the time of polymerization were studied. Percent total conversion, % grafting, and grafting efficiency (%) under different conditions were evaluated and compared. High grafting efficiency (～80%), high % total conversion (～85%), and high % grafting (-95%) were readily obtained. The reaction mechanism for graft copolymer formation is discussed.     

双官能度引发剂引发苯乙烯聚合微观动力学

采用 2 ,5 二甲基 2 ,5 二己酰基过氧化己烷 (DMDEHPH)为引发剂 ,在 5 5～ 80℃下引发苯乙烯聚合 .通过研究影响聚合速率的各种因素 ,得出了聚合速率对单体浓度和引发剂浓度的级数分别为 1 0和 0 5次、聚合活化能为 92 0kJ mol、引发效率为 0 5 5± 0 0 3.温度一定 ,引发效率随引发剂浓度的增加而减小 .求得 6 0和70℃下DMDEHPH向引发剂的链转移常数分别为 0 0 37和 0 0 4 8、向单体的链转移常数分别为 0 5 9× 10 - 4和0 75× 10 - 4.     

Ce(IV) ion initiated graft polymerization of glycidylmethacrylate onto a demineralized bone matrix: effect of reaction parameters

Studies on chemical modification of demineralized bone matrix (DBM) have opened new arenas in the field of clinical orthopedics owing to its potential osteoinductivity with desired chemical functionality. To widen its usage to biomolecular delivery, graft polymerization of glycidylmethacrylate onto DBM was carried out by a free-radical initiating process using ceric ammonium nitrate as an initiator. The evidence of the grafting reaction was examined by chemical analysis using Fourier transform IR spectroscopy. The grafting condition was standardized by regulating the reaction parameters such as the concentrations of the backbone, the monomer and the initiator, the polymerization temperature and time. The optimum polymerization temperature and time to have the maximum grafting yield were 40 °C and 3 h, respectively. The percentage of grafting and the percentage of grafting efficiency were determined as a function of the reaction parameters, and both were found to increasing initially and thereafter decrease in most of the cases. The grafting results are discussed in a detailed fashion and a reaction mechanism is proposed.     

Solvent “Goodness” in Polymer Separation by Flow

The graft copolymerization of methyl methacrylate onto silk fibers was investigated in aqueous solution using the V⁵⁺?thiourea redox system. The rate of grafting was determined by varying monomer, thiourea, acidity of the medium, temperature, initiator concentration, and reaction medium. The percentage of graft yield increases significantly by increasing the initiator concentration up to 0.01 M and thereafter decreases with a further increase of initiator concentration. The graft yield increases with an increase of thiourea concentration up to 10.0 × 10^?4 and then decreases with a further increase of thiourea concentration. The effect of increasing the monomer concentration brings about a significant enhancement in the graft yield. A suitable kinetic scheme has been proposed and the rate equation has been evaluated.     

铬酸引发丙烯酸正丁酯与淀粉接枝共聚反应

作为淀粉改性方法之一 ,不饱和酸及其酯与淀粉接枝共聚反应是一个较新的研究领域 ,其中以 Ce4 +离子作为引发剂的较多[1,2 ] ,也有用Mn3+-H2 SO4 体系 [3]和 Mn[( H2 P2 O7) 3]3-引发体系的[4 ] 。铬酸是一种具有强氧化性的强酸 ,虽然它单独存在时并不引发乙烯类单体的聚合 ,有报道[5] 铬酸可以引发丙烯腈与苎麻纤维素接枝共聚 ,淀粉和纤维素同属于碳水化合物。本文对铬酸引发丙烯酸正丁酯与淀粉接枝共聚反应进行了研究 ,考察了反应条件对接枝反应的影响。1　实验部分1 .1　原料可溶性淀粉 (北京奥特生物技术责任有限公司 ) ,丙烯酸正丁…     

Graft Copolymerization of 2‐Acrylamido‐2‐methyl Propane Sulfonic Acid on Dimethyl Sulfoxide Pretreated Poly(Ethylene Terephthalate) Films Using Cerium Ammonium Nitrate as Initiator

Abstract

In this study, graft polymerization of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) on poly(ethylene terephthalate) (PET) films using cerium ammonium nitrate (CeAN) as an initiator was investigated. Before the polymerization reaction was carried out, films were swelled in dimethyl sulfoxide (DMSO) at 140°C for 1 h. The effect of polymerization temperature, time, initiator, and monomer concentrations on the graft yield were investigated. It was observed that the graft yield was initially increased with increasing temperature, monomer, and initiator concentrations; and then decreased. Graft yield was found to increase with increasing polymerization time up to 5 h, then remain constant. The effects of monomer and initiator inclusions on the grafting yield were also examined. Optimum conditions for grafting were found to be [AMPS] = 1.0 M, [Ce⁴⁺] = 1.5 × 10^?2 M, T = 85°C and t = 5 h. The rate of grafting was found to be proportional to the 0.1 and 0.4 powers of monomer and initiator concentrations, respectively. The overall activation energy for the grafting was calculated to be 11.4 kcal mol^?1. The effect of grafting on PET film properties such as intrinsic viscosity and water absorption capacity were determined. The grafted PET films were characterized with FTIR spectroscopy and scanning electron microscopy (SEM).