高分子负载希夫碱对金属离子的吸附特性

本文报导两种聚氯乙烯负载希夫碱，考察了它们对Ｃｕ＾２＋，Ｈｇ＾２＋，Ａｇ＾＋，Ｃｏ＾２＋，Ｎｉ＾２＋等金属离子的吸附作用。     

金属离子对没食子酸（GA）—BZ非催化振荡反应的影响

测定了一系列金属离子对没食子酸（ＧＡ）－ＫＢｒＯ３－Ｈ２ＳＯ４体系非催化振荡反应的影响。从实验中发现,金属离子对上述振荡反应的影响可分为三类：（１）Ｃｅ３＋、Ｍｎ２＋、Ｆｅ（ｐｈｅｎ）２＋３、Ｂｉ３＋和Ｃｒ３＋,可促进ＧＡ－ＢＺ体系的非催化振荡反应,同时可产生连续振荡等复杂振荡现象;（２）Ｃｕ２＋、Ｚｎ２＋、Ｌ３＋ａ、Ｓｍ３＋、Ｅｕ３＋、Ｎｉ２＋、Ｃｏ２＋、Ｈｇ２＋、Ａｇ＋和Ｈｇ２＋２对振荡反应具有强烈的抑制作用;（３）碱金属和碱土金属离子对振荡反应几乎不发生影响。对上述金属离子的影响机理进行了探索,说明金属离子的电极电势、金属离子与ＧＡ形成络合物或与Ｂｒ－形成沉淀是影响上述振荡反应的主要原因,而金属离子与有机物中间体的偶合催化导致产生连续振荡反应     

溶液pH值,配体及重金属离子Hg^2＋,Cd^2＋,Pb^2＋对细胞色素C电化学活性的影

本文研究溶液ｐＨ值，配体及某些重金属离子对细胞色素Ｃ电化学活性的影响。实验发现：在ｐＨ＝２．０和ｐＨ＝１０．０的磷酸盐缓冲溶液中，细胞色素Ｃ失活，用强的配体ＣＮ＾－与铁卟啉发生配位取代反应虽使溶液相中的细胞色素Ｃ失活，但不影响吸附态的细胞色素Ｃ的活性；重金属离子Ｈｇ＾２＋，Ｃｄ＾２＋，Ｐｂ＾２＋对细胞色素Ｃ电化学活性影响的程度不同，影响大小的顺序为Ｈｇ＾２＋〉Ｃｄ＾２＋〉Ｐｂ＾２＋并对可能的机理进     

金属离子在细菌浸取金属硫化矿中的催化作用

用氧化亚铁硫杆菌浸取某低品位原生硫化矿中Ｃｕ、Ｎｉ时，金属离子对细菌浸矿有明显的催化作用．金属离子（Ａｇ＋，Ｈｇ２＋，Ｃｏ２＋，Ｂｉ３＋）能显著提高细菌浸出Ｃｕ、Ｎｉ的浸出率．对细菌浸Ｃｕ而言，金属离子催化能力排序为：Ａｇ＋Ｃｏ２＋＞Ｂｉ３＋＞Ｈｇ２＋；对浸Ｎｉ，其排序则为：Ｂｉ３＋＞Ａｇ＋＞Ｃｏ２＋＞Ｈｇ２＋．金属离子的浓度、性质及矿石粒度等影响金属离子的催化能力．金属离子的催化作用机理与其性质、矿物结构及细菌氧化作用等因素有关     

不同金属离子对Co/Al2O3中Co的分布和CoMoK/Al2O3催化活性的影响

在γ－Ａｌ２Ｏ３咖入Ｚｎ＾２＋，Ｍｇ＾２＋，Ｃｕ＾２＋或Ｃｒ＾３＋后用漫反射光谱法研究了它们对随后加入的Ｃｏ分布的影响，同时还研究了这些离子对水煤气变换反应催化剂ＣｏＭｏＫ／Ａｌ２Ｏ３的催化活性的影响，发现Ｚｎ＾２＋，Ｍｇ＾２＋具有阻止Ｃｏ进入载体内层的作用，Ｃｕ＾２＋，Ｃｒ＾３＋的作用则相反，四面体配位倾向强的金属离子能阻Ｃｏ进入载体内层，从而促进水煤气变换反应的催化活性，而八面配位倾向强度金属     

聚萘胺膜与金属离子的络合及催化特性的研究

系统研究了聚萘胺膜与Ａｇ、Ｈｇ（２＋）等十余种金属离子的络合特性。以循环伏安法、交流阻抗分析等方法研究了Ａｇ－ＰＮＡ电极对抗坏血酸（Ｈ２Ａ）氧化的催化作用，提出了电极反应的可能机理。Ａｇ－ＰＮＡ电极可用于测定试样中的Ｈ２Ａ含量。     

醇合成用改良铜钴催化体系的表征

应用ＸＰＳ能谱技术和合成气中压反应等对醇合成用铜钴基催化体系进行了表征研究。还原后的铜钴催化剂样品表面上钴以Ｃｏ＾２＋和Ｃｏ＾２＋形式共存，铜主要是Ｃｕ＾０物种。在反应条件下处理后，发生了再氧化现象，即钴主要以Ｃｏ＾２＋形式存在，铜变为Ｃｕ＋或Ｃｕ＾３＋物种。从催化剂的ＸＰＳ和ＸＡＥＳ结果可知，铜和钴之间具有强有相互作用和电荷转移。改良铜钴催化剂具有良好的醇合成的反应活性和碳链增长，助剂钼在样品还     

二价金属离子影响乳酸脱氢酶活性的单扫伏安研究

探讨了５种二价金属离子对乳酸脱氢酶在辅酶ＮＡＤＨ存在下转化丙酮酸为乳酸催化体系的影响、结果表明，Ｚｎ＾２＋，Ｃａ＾２＋与ＬＤＨ活性无影响，Ｍｎ＾２＋有抑制作用，而Ｃｕ＾２＋，Ｍｇ＾２＋在低浓度时有微弱的促进作用。     

以Cyanex272为载体的乳状液膜迁移和分离铅的研究

用Ｃｙａｎｅｘ２７２－Ｓｐａｎ８０－甲苯乳状液膜体系研究了铅的迁移行为，确定了铅迁移的适宜条件。在此条件下，许多常见离子如Ｃｕ＾２＋、Ｃｏ＾２＋、Ｎｉ＾２＋、Ｃｄ＾２＋等均不迁移，Ｈｇ＾２＋迁移率很低。因此Ｐｂ＾２＋能与这些离子得到快速且完全的分离。这对分析测定及三废处理等工作具有实际意义。     

新试剂N—烯丙基—N‘—（氧基对苯磺酸钠）硫脲（ASATu）的合成,表征及其反…

本文报道了新试剂Ｎ－烯丙基－Ｎ＇－（氨基对苯磺酸钠）硫脲（ＡＳＡＴｕ）的合成并确定了结构。该试剂与４５种元素在不同介质中反应，仅有Ｃｕ＾２＋，Ａｇ＾＋，Ｂｉ＾３＋，Ｈｇ＾２＋和Ｆｅ＾３＋等离子产生特征性反应。实验证明，它可作为Ｃｕ＾２＋，Ａｇ＾＋等新的鉴定试剂；在酸性和近中性介质中测定了该试剂与稀土元素等四十多种金属元素反应的摩尔吸光系数。     

氢醌对胆红素氧化过程的促进作用及其分析意义

研究了氢醌与胆红素的作用过程，发现氢醌在碱性条件下可促使胆红素氧化，且胆红素被氧化成胆绿素，此反应过程被证实为自由基反应，考察了介质条件，抗氧化剂等反应过程的影响及其它酚类物质对胆红素氧化的作用情况。     

Kinetics of oxidation of bilirubin and its protein complex by hydrogen peroxide in aqueous solutions

A comparative study of oxidation reactions of bilirubin and its complex with albumin was carried out in aqueous solutions under the action of hydrogen peroxide and molecular oxygen at different pH values. Free radical oxidation of the pigment in both free and bound forms at pH 7.4 was shown not to lead to the formation of biliverdin, but to be associated with the decomposition of the tetrapyrrole chromophore into monopyrrolic products. The effective and true rate constants of the reactions under study were determined. It was assumed that one possible mechanism of the oxidation reaction is associated with the interaction of peroxyl radicals and protons of the NH groups of bilirubin molecules at the limiting stage with the formation of a highly reactive radical intermediate. The binding of bilirubin with albumin was found to result in a considerable reduction in the rate of the oxidation reaction associated with the kinetic manifestation of the protein protection effect. It was found that the autoxidation of bilirubin by molecular oxygen with the formation of biliverdin at the intermediate stage can be observed with an increase in the pH of solutions.     

Bilirubin degradation by uncoupled cytochrome P450. Comparison with a chemical oxidation system and characterization of the products by high-performance liquid chromatography/electrospray ionization mass spectrometry

Bilirubin is a protective antioxidant; however, when its conjugation and excretion are impaired, as in neonatal and hereditary jaundice, bilirubin accumulates and may cause severe neurotoxicity. Degradation of bilirubin takes place (a) on interaction with oxidative free radicals and (b) when cytochrome P450 (CYP) enzymes are uncoupled by polyhalogenated substrate analogues. The products of pathways (a) and (b) above have now been characterized by high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) and the mechanisms of fragmentation in part clarified. Oxidation of bilirubin by uncoupled CYP1A5 and by a Fe-EDTA/H2O2 system produced both biliverdin and an identical profile of dipyrrolic fragments, as detected by positive ESI-MS. A similar profile of oxidation products was found from mesobilirubin, all showing the expected increase in mass, thus providing direct evidence for fragmentation at the central methene bridge of the tetrapyrroles. Two degradation products, also detected by negative ESI-MS, were characterized as dipyrroles retaining the central bridge carbon, with one or two oxygen atom(s) bound (probably as the aldehyde and hydroperoxide derivatives). Ions compatible with propentdyopents and bilifuscins were also detected, but here the assignment was less certain. It is concluded that the first step in the oxidation of bilirubin may be hydrogen abstraction at the central methene bridge. This is followed either by loss of another hydrogen to give biliverdin, or by oxygen binding and fragmentation. Fe-EDTA/H2O2 and uncoupled CYP(Fe=O) may both initiate the reaction, the latter in an attempt to reduce the ferryl oxygen to water. These studies shed light on the CYP uncoupling mechanism and are of potential significance for the therapy of severe jaundice.     

在非质子溶剂中竹红菌甲素敏化光氧化胆红素

胆红素IX_α(胆红素)是哺乳动物体内血红素的代谢产物,由于它与小儿黄疸病光疗的直接关系,以及近来发现它在体内可能作为生物抗氧剂,所以一直受到科学家的重视。在非质子溶剂中胆红素的光氧化可以生成胆绿素IX_α(胆绿素)及一系列单吡咯、双吡咯的衍生物。对于生成单、双吡咯小分子衍生物,用类型Ⅱ(¹O₂为中间体)的光氧化机制很好解释,但对胆绿素的生成到底是经过单重态氧途径,还是离子自由基途径尚不完全清楚。     

Study of the mechanism of the photochemical oxidation of bilirubin by high-performance liquid chromatography

The photochemical degradation of bilirubin was studied in vitro using high-performance liquid chromatography and spectrophotometry. Attention was centered on the formation of biliverdin, which is produced as an intermediate in the photooxidation catalysed by riboflavin. approximate values of the overall and partial relative rate constants were calculated using the physiochemical criteria for a pseudo-monomolecular reaction. A more precise evaluation was made by non-linear regression programmes on a Hewlett-Packard 9835 A computer. In addition to the formation of biliverdin, attention was also paid to accompanying processes affecting the reaction mechanism, which were explained as aggregation and dimerization of bilirubin and biliverdin. It was also found that during phototherapy of newborn babies suffering from hyperbilirubinaemia the level of biliverdin in the plasma increased. The results are discussed from the point of view of phototherapy.     

Study of the mechanism of the photoisomerization and photooxidation of bilirubin using a model for the phototherapy of hyperbilirubinemia

Liquid chromatography was employed for a study of photochemical degradation of bilirubin in the complex with human albumin, using a model system in the presence of riboflavin. The concentrations of bilirubin, the photoisomers and biliverdin were monitored. The reaction mechanism was verified using a quantified mathematical model and was represented by a reaction scheme. Photoisomerization is the initial process, followed by photooxidation to degradation products of the tetrapyrrole skeleton, with formation of biliverdin as an intermediate. The blood of newborns that were irradiated for treatment of hyperbilirubinemia was studied for the sake of comparison. The effect of some biochemically important substances was followed, in view of possible inhibition of the processes. The experimental results demonstrate that riboflavin acts as a catalyst, even at the concentrations typical for its occurrence in blood. The results are discussed from the point of view of the mechanism of bilirubin degradation during phototherapy.     

铜(Ⅱ)及其配合物催化胆红素氧化动力学的研究

本文用电化学，吸收光谱等方法对Ｃｕ（２＋）及其配合物与胆红素在碱性（ｐＨ１０）条件下的作用规律进行了研究．发现Ｃｕ（２＋）及其配合物对胆红素的氧化的催化作用依配合物的稳定性和配体齿数不同而异．在胆红素的氧化过程中，真正起氧化作用的是溶解氧．     

Kinetics of the formation of biliverdin during the photochemical oxidation of bilirubin monitored by column liquid chromatography

In the photochemical oxidation of bilirubin, biliverdin is formed as the primary product and is further degraded. This photooxidation is especially significant in the presence of riboflavin. Column liquid chromatography was used to monitor the kinetics of this reaction. The biliverdin concentration amounts to a maximum of ca. 38% of the total loss of bilirubin in experiments in vitro. It is probable that this mechanism is also operative during phototherapy. The formation of a product of the photooxidation of biliverdin that has not yet been identified has been observed; the product behaves as a dimer. A method for the determination of biliverdin in the blood of newborn infants has been developed. It has been found that the biliverdin content increases during hyperbilirubinaemia.     

吸附于银胶颗粒表面的胆红素及胆绿素分子吸附取向研究

胆红素、胆绿素作为重要的生物小分子被广泛研究。本文采用表面增强拉曼光谱技术获得了胆红素和胆绿素分子吸附于银胶颗粒表面的拉曼光谱。通过对其谱带的指认分析,表明胆红素形成了三对内氢键,并以其两个吡咯亚甲基酮环沿银胶颗粒表面切向方向镶嵌在银胶颗粒上,而胆绿素则以顺式－顺式－顺式构型平躺吸附于银胶颗粒表面。     

Kinetics and Mechanism of Bilirubin Oxidation by Benzoyl Peroxide in Dimethyl Sulfoxide

The kinetics of the redox reaction of bilirubin by the action of benzoyl peroxide in dimethyl sulfoxide was analyzed. It is shown that the first reaction product is biliverdin, which oxidizes to purpurin and further to choletelin. The kinetic and activation parameters of the oxidation reactions were obtained. A kinetic model of the process was proposed. An assumed route of the reaction is related to the exchange interaction of CH protons of methylene and methine spacers with free radicals in the rate‐limiting step with the further destruction of the “ridge‐tile” pigment conformation. The mechanism steps are confirmed by quantum‐chemical calculations and HPLC. It is found that in organic solvents the end products of bilirubin oxidation are not monopyrrolic derivatives. The data obtained will be useful in constructing antioxidant action models of the pigment.