聚乙二醇衍生物的合成研究进展

功能化聚醚尤其是功能化聚乙二醇衍生物,如聚乙二醇对甲苯磺酸酯、胺基聚乙二醇、羧基聚乙二醇、聚乙二醇－聚酯及聚乙二醇－聚氨基酸共聚物等在有机合成、多肽合成,高分子合成、药物的缓释控释、靶向施药等多方面具有广泛的应用前景,目前它已成为国内外研究的热点,本文综述了近年来聚乙二醇衍生物的合成研究进展。     

单萜吲哚生物碱Alstonerine的合成研究进展

Alstonerine属于单萜吲哚生物碱,除其结构很有特征外,还报道对两株人肺癌细胞具有细胞毒性,因此,它自然就成为合成化学的重要目标.已经有多种合成策略用于构建这个结构体系:包括Pictet-Spengler反应和Dieckmann缩合反应、烯烃复分解关环反应、膦配体催化的[4+2]关环/Friedel-Craft环化、氮杂-Diels-Alder反应/分子内Heck反应、Pauson-Khand反应等.本工作根据构建环系的不同反应系统总结了Alstonerine的合成方法.大部分合成反应步骤较多,适合工业生产的有效合成方法还有待于进一步探索.     

前列腺素合成研究的进展

根据前列腺素的结构特点,着重讨论用Ｃｏｒｅｙ的逆合成法进行推导合成,并讨论前列腺素的合成方法和研究进展,参考文献１１篇。     

取代喹啉新化合物的光化学合成

取代喹啉新化合物的光化学合成谭成权（大连大学化学化工系１１６６２２）谭成权５１岁，教授，从事金属有机化合物的合成及反应、杂环化合物的合成及氮杂二烯的光化学反应研究。１９９７－０６－３０收稿关键词１－Ｎ－苯甲酰基－４－氨基－１－氮杂丁二烯紫外光照射光环...     

流光放电合成NH3研究

NH3是一种重要的化工原料,是氮肥工业的基础.但常规的合成NH3技术,能量消耗是十分巨大的,占总成本的70%[1].而且其生产条件恶劣、设备庞大、运行费用高.因此,从60年代起,许多试图在温和条件下合成NH3的新方法应运而生[2].其中,常压非平衡等离子体合成NH3是较为理想的一种.它是将H2、N2气体按一定比例混合,在超强窄脉冲电场中产生流光放电,使气体分子激发、电离、自由基化,成为高浓度的非平衡等离子体,高活化状态的H、N原子化合成为NH3分子.     

成对电合成技术

本 文主要 介绍作者 在成对电 合成技 术的研究 成果,结 合研究实 例,介绍 了工艺条 件如电极材 料、电流 密度及电 解温度 等的优化 选择以 为同行参 考;并 将成 对电 合成 技术 归纳 分类, 开拓成对有 机电合 成思路,促 进有机 电合成技 术的发 展．     

CO加氢合成异丁烯研究进展与展望

综述了由合成气选择性合成异丁烯的各种催化剂体系，比较和评价了这几种催化剂体系的活性，选择性以及反应条件，重点概述了文献对这一反应机理的研究，并展望了这一领域存在的研究机遇。     

有机硼在不对称合成中的应用

本文综述了重要的手性有机硼试剂的合成，反应，机理及其在不对称合成中的应用。     

有机合成中的合成子与合成等效剂

合成子和合成等效剂是有机合成的发展过程中提出的新概念。深刻了解这一概念及其有关知识对于提高有机合成设计水平和发展有机合成设计技巧,尤其在运用计算机进行有机合成路线的择优中,都具有一定的意义。本文将分别就合成子、合成等效剂以及合成子的类型转换作一介绍。     

末端羟基炔烃的合成——Ⅱ.4-烃基-3-丁炔-1-醇的合成(英文)

本文报道一种以四氢呋喃为起始原料,合成4-烃基-3-丁炔-1-醇的新方法。该法完全避免了传统乙炔路线所必须的低温、液氨等苛刻的条件。鉴于这种炔烃可容易地经还原制得高纯度的指定构型的烯烃,而许多天然产物如香料(叶醇)、昆虫信息素等都具有这一结构,因此这一路线为合成这类化合物提供了一个简便、实用的方法。     

Alteration in photosystem II photochemistry of thylakoids isolated from senescing leaves of wheat seedlings

Wheat seedlings, grown for 7 days in the light, were allowed to senesce in the light or dark, and the change in the photosystem II (PS II) photochemistry of chloroplasts isolated from the primary leaves of these seedlings was investigated. The decrease in oxygen evolution and the fast fluorescence results indicated that the impairment of PS II in the leaves of seedlings senescing in the light was different from that in the leaves of seedlings senescing in the dark. Thermoluminescence studies showed a structural modification in the Q_B protein of chloroplasts isolated from leaves senescing in the light and an alteration in the S state transition of chloroplasts isolated from leaves senescing in the dark.     

Calibration methods for microdialysis sampling in vivo: muscle and adipose tissue

Calibration methods for microdialysis sampling were studied in the muscle and adipose tissue of rats. Both the delivery method and the no-net-flux method were used to determine the extraction efficiency (EE) of acetaminophen and caffeine in both tissues. There was no concentration dependence of the EE either in vitro or in vivo for either acetaminophen or caffeine. The EEs determined by the delivery and no-net-flux methods were not different. However, the EEs of both caffeine and acetaminophen determined in vitro were significantly higher than those determined in the muscle and adipose. This indicates that mass transfer in the tissue is the rate-determining factor for the EE in vivo. The relative difference between the EE in vitro and the EE in the muscle was smaller than the difference between the EE in vitro and the EE in the adipose. In addition, the EE in the muscle decreased more than the EE in the adipose after the animal was euthanized. This indicated that exchange between the extracellular fluid and plasma is the rate-determining step in mass transport relative to microdialysis sampling. This has a more significant effect on the EE in the muscle than the EE in the adipose. Both the delivery and no-net-flux methods can be used to calibrate microdialysis probes in the muscle and adipose.     

壳聚糖及其在分析化学中的应用

综述了壳聚糖、甲壳素在污水处理、电化学、原子吸收光谱、高效液相色谱、吸光光度法中的应用。引用文献28篇。     

ESR方法检测竹红菌素的半醌负离子自由基

从顺磁共振波谱检测到通过竹红菌素的光诱导还原和基态竹红菌素跟脂肪胺的电子转移两条途径所得到的自由基信号, 并由电化学还原得到同一自由基, 确认它为半醌负离子自由基。竹红菌素溶液中加入芳香胺观察不到ESR信号。它的3,10位上与醌基相邻近的羟基离解以后, 无论在基态还是在激发态都观察不到ESR信号。此外, 还从吸收光谱观察到半醌负离子自由基吸收以及竹红菌素跟脂肪胺之间的相互作用。     

汽油铅与血铅的关系

论述了汽油铅对人体血铅水平的影响，主要内容包括：血铅水平与大气铅水平的关系，大气铅水平与加铅汽油耗量的关系，汽油铅耗量与居民血铅水平的关系。     

Analytical strategies to determine antibiotic residues in fish

The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised.     

Radial structure and property relationship in the thermal stabilization of PAN precursor fibres

Here we report on the role of oxygen in the evolution of radial heterogeneity in the fibre structure and properties of PAN fibres stabilized in air and vacuum at different temperatures. Modulus mapping by Nano-indentation showed heterogeneous modulus distribution in the fibres treated in air, while no variation in modulus was observed in fibres processed in vacuum. Raman spectroscopy and elemental analysis revealed that the temperature dependent oxygen diffusion from skin to core of the fibres assisted in the evolution of higher extent of sp²-hybridized carbons in the skin compared to core of the air treated samples. Conversely, no radial structure variations were observed in the vacuum treated fibres. Higher modulus in the skin of air-treated fibres was due to the formation of compact structures which was associated with the enhanced intermolecular interactions facilitated by the formation of C=C bonds within the polymer backbone, promoted by oxidative-dehydrogenation reaction. Supporting these observations, the fracture morphology examined by SEM showed a brittle fracture in the skin and ductile fracture in the core.     

Effect of the displacement reaction on the composition of the magnetic layer in electrodeposited layered nanostructures Co-Cu/Cu and Ni-Cu/Cu

Methods of stripping voltammetry, quartz microgravimetry, and x-ray-fluorescence analysis are employed to explore the copper displacement process on thin electrodeposited layers of pure cobalt and nickel and on deposits of these metals with inclusions of copper. The displacement reaction proceeds at a considerable rate on cobalt in the sulfate and sulfosalicylate solutions and virtually does not proceed on nickel in both the sulfate or sulfate-chloride solutions. An estimate of the rate of the copper displacement reaction following a change in the concentration of copper ions in the solution and in the pH of the sulfosalicylate solution is given. A decrease in the contact exchange rate is facilitated by a decrease in the concentration of copper ions in solution and their participation in the formation of complexes.     

An Evidence-Based Review of Application Devices for Nitric Oxide Concentration Determination from Exhaled Air in the Diagnosis of Inflammation and Treatment Monitoring

The measurement of nitric oxide (NO) in exhaled air is used in diagnostics and monitoring the pathologies not only in the respiratory system but also in the oral cavity. It has shown a huge increase in its level in asthma and diseases of the oral cavity. It seems reasonable to undertake research on the impact of inflammation on the level of NO in exhaled air. The aim of the study is to make an evidence-based review of the application of NO levels in exhaled air in the diagnosis of inflammation and treatment monitoring on the basis of selected measuring devices. Methods and Results: This paper presents an example of the application of NO measurement in exhaled air in individual human systems. Selected measuring devices, their non-invasiveness, and their advantages are described. Discussion: The usefulness of this diagnostic method in pathologies of the oral cavity was noted. Conclusions: Measuring the level of NO in exhaled air seems to be a useful diagnostic method.     

Changes in wine volatile compounds of varietal wines during ageing in wood barrels

Twelve single-variety wines were aged in new American oak barrels. A control wine of each variety without ageing in wood was also studied. The volatile aroma composition of these wines was analysed after the following combinations of time in wood and time in bottle: 0 months in wood plus 18 months in bottle, 4 months in wood plus 14 months in bottle, 9 months in wood plus 12 months in barrel and 12 months in barrel plus 6 months in bottle.The data obtained were studied by two different multivariate methods: factor analysis by principal components and stepwise linear discriminant analysis. The results obtained showed that the capacity of wine to extract the volatile compounds from the wood depended on the variety of grape used. Furthermore, it was also found that the changes in the volatile composition of the wines induced by the wood ageing were more important during the first 4 months. In addition, the volatile compounds studied allowed to differentiate and correctly classify the wines according to the time they had been in contact with the wood.