黄原胶以三价铬交联的水凝胶的脱水行为

对黄原胶／三价铬水凝胶在７０，８０和９０℃下的脱水行为进行了研究．脱水与凝胶的交联密度即参与交联反应的三价铬的含量有密切联系．突发脱水之后的过程可以用一级反应动力学描述，反应速度常数随三价铬的浓度和温度的增高而增大，活化能为３４．５ｋｃａｌ／ｍｏｌ．一价盐（ＮａＣｌ）的含量对脱水过程没有影响．     

铬与人体健康研究

对铬与人体健康关系作了综述，包括：铬作为人体必需微量元素的生理功能，葡萄糖耐量因子定义和结构推测，以及与人体健康有关的生理临床作用研究进展状况，以引起更多的科技工作者对这一领域的关注和重视。     

微量元素与心血管疾病Ⅱ.微量元素在心血管病中的可能作用及机制

心血管病的发生和发展至少与体内35例元素不平衡有关，本文重点叙述了镁，钙，铜，铬，硒，锰，铁，锌，锶，铅等10种元素在心血管病中的可能作用及机制。附5图，20表和63篇参考文献。     

微量元素的生物学作用及其与脂代谢和肥胖的关系

微量元素在脂代谢中有重要作用，阐述了锌、铜、钒、硒等的生物学作用及其与脂代谢和肥胖的关系。     

催化动力学极谱法测定痕量亚硝酸根

在硫酸介质中，痕量亚硝酸根对溴酸钾氧化酸性铬深蓝的反应有极强的催化作用，研究了最佳反应条件，发现在氨缓冲溶液中酸性铬深蓝具有良好的极谱峰，以极变法监测催化反应过程中酸性铬深蓝浓度的变化，建立了催化动力学极谱法测定痕量亚硝酸根的方法，方法的线性范围为0．20－1．34μg.ml^-1，检出限为0．088μg.ml^-1，应用于雪水，雨水中痕量亚硝酸根的测定，结果满意。     

茶汤及河水中铬的形态分析

本文采用７１７型强碱性阴离子交换树脂、活性炭分离富集与偶氮胂Ⅲ光度法结合，研究了铬形态的分离及测定，提出了铬的形态分析方法，有此法测定了茶汤及河水中铬的总量，悬浮态．溶解态、无机态、有机态、Ｃｒ（Ⅲ）和Ｃｒ（Ⅵ）。茶汤中铬主要以有机态存在，而河水中铬则主要以悬浮态存在。     

铬（Ⅵ）—SAF—H2O2褪色光度法测定污水中微量铬（Ⅵ）

在硼砂－氢氧化钾介质中，铬（Ⅵ）对过氧化氢氧化水杨基荧光酮褪色有催化作用，加入三乙醇胺可阻止催化反应。以此建立了微量铬（Ⅵ）的褪色光度法测定，该法不需加热，允许干扰量较大，灵敏度为１．０×１０＾－９ｇ／ｍＬ，ε＝１×１０＾５Ｌ．ｍｏｌ＾－１，０．０５－５．０μｇ／２５ｍｌ铬符合比尔定律，用于测定某些污水中之铬（Ⅵ）不需分离富集，其结果与二苯碳酰二肼法相符，加样回收９６－１０３％。     

铬（Ⅵ）－SAF－H_2O_2褪色光度法测定污水中微量铬（Ⅵ）

在硼砂－氢氧化钾介质中，铬（Ⅵ）对过氧化氢氧化水杨基荧光酮褪色有催化作用，加入三乙醇胺可阻止催化反应。以此建立了微量铬（Ⅵ）的褪色光度法测定，该法不需加热，允许干扰量较大，灵敏度为１．０×１０￣（－９）／ｍＬ，ε＝１×１０￣５Ｌ．ｍｏｌ￣（－１）．ｃｍ￣（－１），０．０５～５．０μｇ／２５ｍＬ铬符合比尔定律，用于测定某些污水中之铬（Ⅵ），不需分离富集，其结果与二苯碳酰二肼法相符，加样回收９６～１０３％。     

镧铬酵母中铬含量的测定

采用在培养基中加入La2O3的方法，制备得到了镧铬酵母，并对其总铬、无机六价铬及有机铬的含量进行了分析，结果表明：镧铬酵母中总铬含量可达到708．3μg／g，有机铬含量可达到639．0μg／g，是未加La2O3的铬酵母样品的近3倍；而六价无机铬占总铬的百分含量却由1．60％降至0．72％。通过紫外光谱和红外光谱分析，发现有机铬在260nm和478cm^-1处有特征吸收峰。     

铬与健康

对铬与人体健康的关系进行了综述，主要内容包括：三价铬的作用、六价铬的作用和环境中的铬。     

Two-phase Aqueous Extraction of Chromium and Its Application to Speciation Analysis of Plasma Chromium

Chromium is one of the essential trace elements to our body and present mainly in its trivalent form in body fluids. It is believed that chromium plays a key role in carbohydrate and lipoprotein metabolism and its variation is closely related with diabetes and arteriosclerosis. However, its existing state and relationship have not been thoroughly understood due to the trace amount of chromium in body and the absence of proper sample preparation method for speciation analysis.     

Bioavailability, bioaccumulation and tolerance of chromium: consequences in the food chain of freshwater ecosystems

Many abiotic and biotic factors can influence the partitioning equilibrium of heavy metals, thus influencing metal impact on aquatic environments. Unicellular algal species release soluble organic substances able to complex metals. In our laboratory a Cr-tolerant strain was selected and isolated from a wild type strain of Scenedesmus acutus. The exudates released by the two strains counteracted the growth inhibition caused by Cr(VI) and the exudates of the Cr-tolerant strain were more effective. On the contrary, the exudates did not reduce chromium toxicity to the cladoceran Daphnia magna. The reduction of chromium effect on algae seems the consequence of an algae-specific interaction among Cr(VI), exudates and algal cells. Chromium uptake resulted to be energy-dependent since bioaccumulation rate in subdued light condition was lower than at high light intensity. The effect of Cr(VI) on algae changed depending on metabolism of the cells and in particular it seemed to be related to the bioaccumulation rate. Tolerance in the selected strain could not be ascribed to a lower uptake of chromium. The difference in sensitivity to chromium between the two strains was exploited to evaluate if tolerance acquired by algae could have consequences for Daphnia. After treatment with Cr(VI), the two strains of S. acutus were used as food source for D. magna. The results indicate that chromium is accumulated by algae in a form not available for daphnids and that Cr tolerance acquired by the algae can be of some advantage to the consumer organism.     

Development of a procedure for the determination of chromium in samples of urine and serum by neutron activation analysis

Summary Since the mid-fifties the possibility of a causal relationship between deficient chromium and insulin metabolism and the manifestation of certain varieties of diabetes mellitus has been presumed. The determination of the chromium status under pathophysiological conditions may be helpful for the study of this problem. For these purposes an analytical procedure as reference system was developed which allows the determination of chromium in biological matrices down to the concentration of 0.03 ng/ml. It is based on NAA and is used in the framework of a commonly used procedure based on GF-AAS. For its application blood and urine samples are freeze-dried and irradiated. After wet digestion with HNO₃ in a microwave combustion system chromium is separated for measurement from the matrix nuclides with the help of the ion-exchanger Cellex-P. The individual steps of the procedure were evaluated by means of tracer experiments.Dedicated to Professor Dr. V. Krivan on the occasion of his 60th birthday.     

Selective ethylene oligomerization: Recent advances in chromium catalysis and mechanistic investigations

Selective production of linear α-olefins is of significant commercial interest. Recently discovered catalytic systems based on titanium, tantalum, and chromium show remarkable selectivity and productivity for the oligomerization of ethylene to 1-hexene or 1-octene. Chromium-based catalysts are the most selective and active and show the highest structural diversity. This paper discusses the most recent advances in chromium chemistry related to selective olefin oligomerization. Aspects regarding ligand design, catalyst generation, selectivity for different products, and reaction mechanism are presented. Isotopic labeling protocols designed to distinguish between various mechanisms of catalysis are reviewed.     

Anti-adipocyte scFv-Fc Antibody Suppresses Subcutaneous Adipose Tissue Development and Affects Lipid Metabolism in Minipigs

Anti-adipocyte monoclonal antibody has been shown to reduce body fat mass in animals. Here, we investigated the effects of an anti-adipocyte antibody (single-chain variable fragment and crystallizable fragment, scFv-Fc) on pig subcutaneous adipose tissue development and lipid metabolism. The scFv-Fc antibody did not alter feed intake or body weight of treated pigs. It suppressed subcutaneous adipose tissue development by reducing the percentage of larger adipocytes, which led to a reduction in body fat mass and subcutaneous adipose tissue thickness. Body fat mass was reduced by reducing triglyceride biosynthesis and promoting triglyceride lipolysis in adipose tissue. There was an increase in lipoprotein lipase mRNA expression in adipose tissue and activity in blood and an enhanced transportation of circulating high-density lipoprotein, low-density lipoprotein, and free fatty acids. Blood concentrations of triglyceride, total cholesterol, glucose, insulin, and adiponectin and mRNA expression of adiponectin in adipose tissue remained unaffected. These findings suggest that anti-adipocyte scFv-Fc antibody may have an application for reducing body fat mass in obese subjects.     

多糖铬配合物的研究进展

从铬配合物的性能、种类与功能,多糖铬和寡糖铬配合物的合成方法及其铬含量的检测、糖铬配合物的生物活性与毒性研究等方面进行了综述,分析了多糖铬配合物研究和应用等方面存在的问题。     

Flow-Injection Chemiluminescence as a Means of Studying the Metabolism of Unbound Chromium(III) in Rabbit Blood with On-Line Microdialysis Sampling

In this paper, we present an in-vivo, on-line, real-time analytical system for monitoring the metabolism of free chromium(III) in rabbit blood. This system includes microdialysis sampling, ion-exchange on-line separation and chemiluminescence detection. The results show that none of the co-existing substances in the blood, including protein and other small molecules, interfere with the determination. CrCl₃·6H₂O was administrated orally (0.5 g), and the microdialysis probe was utilized to sample rabbit blood with a perfusion rate of 10 µL min⁻¹. The dialytic efficiency of chromium(III) under the experimental conditions was 18.1 ± 5.1% (n=3). The concentration-time curve of chromium(III) is in accordance with the one-compartmental open model, the T_1/2 is 16.62 min.     

Effect of current density on poisoning rate of Co-containing fuel cell cathodes by chromium

Variation of electrochemical performance of a La_0.58Sr_0.4Co_0.2Fe_0.8O₃ (LSCF) cathode due to chromium gas-phase deposition has been studied at 800°C. The highest degradation rate is observed under open circuit conditions and is related to formation of a SrCrO₄ layer on the surface of an LSCF cathode. This results in an increase in both polarization and ohmic electrode resistance. The degradation rate is 3.7 and 0.5 Ohm cm²/1000 h, accordingly. When external polarization is applied, the degradation rate decreases considerably. It is found that the amount of chromium in the cathode bulk changes nonlinearly at an increase in current density. At 0.2 A/cm², the overall amount of chromium is twice as large as under open circuit conditions, but the degradation rate is three times lower. Herewith, a considerable amount of chromium was found both on the cathode surface and in its bulk. The results of model experiments show that exposure to external electric current leads to migration of chromium cations in the bulk of the porous cathode. It is shown that the growth of a SrCrO₄ layer on the surface of an LSCF cathode and penetration of chromium into the cathode bulk becomes slower at the current density of 0.5 A/cm². Under similar conditions (temperature, current density, and time), the amount of chromium in an LSCF cathode is 2.5–7.3 times larger as compared to that in La_0.65Sr_0.3MnO₃. However, the rate of degradation of electrochemical performance of an LSCF cathode is lower, which points to its higher tolerance towards the presence of chromium. This is due to higher oxygenionic conductivity of an LSCF cathode.     

欧盟玩具安全新指令化学要求及测试方法综述

2013年开始实施的欧盟玩具安全指令对化学物质的检测要求更加严格,限制迁移元素从8种增加到包含三价铬、六价铬和有机锡的19种,增加了对N-亚硝胺类物质的迁移量和致敏性芳香剂的限制;限量降低,铅、镉、六价格、有机锡限量分别只有3.4,0.5,0.005,0.2 mg/kg,传统玩具检测使用的ICP-OES和GC-MS已无法满足六价铬、有机锡、亚硝胺、芳香剂的检测要求。该文简述了指令的化学相关要求以及相应的检测方法,重点介绍了六价铬和有机锡检测方法的技术进展和技术难点。