含偶氮苯光学活性侧基聚合物研究进展

综述了含偶氮苯光学活性侧基聚合物近年来的发展概况 ,介绍了多种聚合体系的类型。由于偶氮苯光于活性侧基的存在 ,使得这些聚合物具有光致变色性、非线性光学活性、光学各向异性等光学性能 ,在光信息存储材料、非线性光学材料、液晶材料、光电子器件、生物分子活性光调控、纳米技术等诸多领域都有广泛的应用。     

含刚性链节和脲端基聚醚增韧剂改性环氧树脂的研究—反应活性及力学 …

合成了一系列既含环氧丙烷聚醚柔性间隔基，又含刚性介晶结构单元的端脲基活性改性剂，并对其改性环氧树脂Ｅ－５１／双氰双胺体系的固化反应活性，改性剂含量对增韧体系动态力学性能及冲击性能的影响进行了研究。     

新黄酮类化合物的脱甲基反应及其抗氧化活性

以3,4-二甲氧基苯甲醛(1)为起始原料,使用文献已报道的三氟乙酸法合成了3个含两个甲氧基取代基的新黄酮类化合物4a-4c,在新制碘化铝的催化下发生脱甲基反应,合成了3个含多个羟基取代基的新黄酮类化合物5a-5c,产率均高于90%.所有目标化合物均经过IR,~1H NMR,ESI-MS对其进行了结构确认.通过测定羟基自由基和DPPH自由基清除活性两个方面评价其抗氧化活性,结果发现,脱甲基后产物活性均增强.     

含胍基抗菌聚合物的合成及应用

开发能与细菌非特异性结合的新型抗菌剂是解决细菌感染难题的方法之一。本文首先介绍了一种具有持久广谱高效抗菌性、无真核细胞毒性和细菌很难产生耐药性的含胍基抗菌聚合物;接着详细介绍了含胍基抗菌聚合物与细菌非特异性静电结合的抗菌机理;然后重点评述了主链含胍基抗菌聚合物、侧链含胍基抗菌聚合物以及表面接枝含胍基抗菌聚合物的设计理念、合成方法和抗菌性能;最后对新型含胍基抗菌聚合物的可控合成策略及应用前景进行了展望。     

含噻二唑基哒嗪酮类化合物的合成及杀虫活性

含噻二唑基哒嗪酮类化合物的合成及杀虫活性     

N-5-四唑基-N′-芳甲酰基脲的合成及其生物活性

合成了 15个新的含四唑基的芳甲酰基脲类化合物 ,用IR ,1HNMR和元素分析证实了它们的结构 ,并进行了初步的生物活性试验 ,生测结果证明一些目标化合物具有优良的植物生长调节活性 ,其中N 5 四唑基 N′ 对甲氧基苯基甲酰基脲(2h)和N 5 四唑基 N′ 对溴苯基甲酰基脲 (2j)具有很好的生长素活性 ,2h ,2j和N 5 四唑基 N′ 对甲基苯基甲酰基脲 (2m )具有优良的细胞分裂素活性     

含N、S官能基聚硅烷*

综述了近年来含N、S官能基聚硅烷的研究进展。介绍了吡啶、联吡啶、吡咯等含N官能基与噻吩、硫代官能团等含S官能基取代聚硅烷的制备和光电性能表征,概括了含N,S官能团聚硅烷的分子设计、物理性能与应用领域。最后展望了含N、S官能团聚硅烷研究的发展方向与应用前景。     

N－5－四唑基－N′－芳甲酰基脲的合成及其生物活性

合成了15个新的含四唑的基的芳甲酰基脲类化合物，用IR，^1H NMR和元素分 析证实了它们的结构，并进行了初步的生物活性试验，生测结果证明一些目标化合 物具有优良的植物生长调节活性，其中N－5－四唑基－N′－芳甲酰基脲（2h)和N －5－四唑基－N′－对溴苯基甲酰基脲（2j)具有很好的生长素活性，2h,2j和N－ 5－四唑基－N′－对甲基苯基甲酰基脲（2m）具有优良的细胞分裂素活性。     

含茂铁基三联吡啶钌功能分子的光电性质*

多吡啶钌配合物在光化学、光物理、电化学、电子转移、能量转移、分子组装和分子识别等研究领域都扮演着非常重要的角色。茂铁基具有化学稳定性、氧化还原活性、富电子性和结构易修饰等特点,使其在功能分子的设计与合成等领域得到广泛的应用。结合茂铁的电化学活性和[Ru(tpy)₂]²⁺的光学活性,在[Ru(tpy)₂]²⁺分子中三联吡啶的4′位上引入茂铁基,可以构筑性能优良的光电功能分子。本文介绍了近年来含茂铁基（尤其是具有扩展共轭体系的茂铁炔基或茂铁苯炔基）三联吡啶钌光电功能分子的研究进展,并结合本课题组的研究成果探讨了炔基的引入、炔基位置的不同和炔基长度（由单炔基到双炔基）的变化对该类化合物光电性质的影响。     

新型黄烷酮类衍生物的合成、杀菌活性及定量构效关系研究

设计合成了14个含不同性质取代基的黄烷酮类化合物,并采用核磁共振氢波谱、质谱和元素分析对所有化合物的结构进行了表征.在系统测定化合物对水稻稻瘟病抑制活性的IC₅₀值的基础上,采用Hansch-Fujita方法和CoMFA方法对其定量结构活性关系进行了系统研究,结果发现,化合物的疏水性质、极化效应以及最高空轨道能级对杀菌活性有重要影响,化合物的疏水参数越小,分子越容易极化,则化合物的杀菌活性越高.此外,最高空轨道能级越低,化合物越容易接受电子,其杀菌活性也相应提高.通过考察∑π、clgP以及lgK与化合物杀菌活性的相关性,发现lgK能较好地反映该类化合物的疏水效应.三维定量构效关系研究表明,B环2,3,4位上含有较大体积的取代基,而6位含较小体积的取代基,有利于提高其杀菌活性.     

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.     

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.     

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.     

Changes in density and surface tension of water in silica pores

 The density and surface tension of water in small pores of silicas have been investigated. These physical properties of water in the pores were calculated from a comparison of pore volumes and pore radii which were estimated from adsorption and desorption isotherms of nitrogen and water. Below a pore radius of about 5 nm both the density and the surface tension of water in the pores were smaller than those of the bulk liquid and decreased with a decrease in pore size. The density of water in the pores decreased with an increase in the concentration of surface hydroxyl groups. Similarly the surface tension of water in the pores is influenced by the surface hydroxyl groups. Anomalous changes in the density and surface tension of the water in the pores are attributed to the interaction of water molecules with surface hydroxyl groups and hydrogen-bond formation among water molecules. Received: 20 April 1999 Accepted in revised form: 17 November 1999     

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.     

青藏高原湖泊影响锂元素迁移和富集的矿物、元素及环境因素——以西藏郭扎错钻孔沉积物为例

作为我国战略性矿产的锂矿,主要赋存于青藏高原盐湖中。湖泊系统中,锂的富集和迁移规律关系到锂矿的高效提取和未来锂矿的储量估算。本文以西藏咸水湖郭扎错的钻孔沉积物为例,结合AMS14C年代和Mg元素含量变化,系统分析了孔隙水、碳酸盐矿物和硅酸盐矿物的锂含量变化,探讨了矿物、镁元素、环境变化和早期成岩作用等对锂元素迁移和富集的影响。郭扎错沉积物中锂和镁大部分存在于硅酸盐矿物中,锂和镁较高的相关性说明二者存在于相同的硅酸盐矿物中,如粘土矿物。大约90%的锂赋存在硅酸盐矿物中,约8.5%的锂赋存在碳酸盐矿物中,孔隙水中的锂含量占比仅约1.5%。碳酸盐矿物中Mg/Li摩尔比值为78–270,是孔隙水中10多倍,而硅酸盐矿物中的Mg/Li摩尔比值稳定在24–29之间。水–沉积物相互作用促进硅酸盐矿物中锂的释放,咸水环境下释放的锂多于淡水环境下。碳酸盐矿物中,锂和镁主要存在于方解石中。镁离子对锂离子的迁移具有阻碍作用,低温、高盐度下的阻碍作用更强。湖泊沉积物可能是湖水锂的一个重要来源。     

Effect of pulp composition on the characteristics of residuals in CMC made from such pulps

Four different spruce sulphite pulp samples were used for the preparation of carboxymethylcellulose (CMC). The characteristics of the unreacted fibre and particle residuals obtained in the CMC-preparation were used to establish a correlation between the hemicellulose in the pulp and the intrinsic viscosity, i.e.,␣cellulose chain length and the occurence of unreacted residuals. It was shown that the residual particles in the CMC consisted of fibres, fibre fractions and gel particles of different degrees of substitution. The results suggested that pulps with long cellulose chains, i.e., pulps with high intrinsic viscosities, resulted in particles that were more substituted and more swollen. These pulps also resulted in more substituted hemicelluloses in the CMC and more substituted residuals. It was also suggested that galactoglucomannan in the cellulose pulps is favourable for the swelling which results in more substituted hemicelluloses in the CMC and more swollen residuals. The amount of residuals was influenced mainly by the characteristics of the cellulose in the pulp. It is therefore believed that a combination of high viscosity and a suitable combination of hemicelluloses is the most favourable way of eliminating the occurrence of undissolved residuals in CMC.     

Electrophoretic studies for determining soy proteins–xanthan gum interactions in foams

The aim of this work was to elucidate soy proteins–xanthan gum interactions at a molecular level by studying protein composition at the air–water interface of foams and in the solutions used to make them and to see if the different properties of heat denatured protein were reflected in the proportions in which they were present at the interface or in the ability to interact with xanthan. To this end SDS-PAGE and densitometry was employed. Initial protein concentration and xanthan influenced the composition of proteins in the solutions used to make the foams. The increase in NSP concentration of solutions (0.5–6 wt.%) in the absence of xanthan promoted the formation of aggregates of low molecular weight (160 kDa), the association of A an B polypeptides and a decrease in and ′ subunits. As DSP concentration of solutions increased, an increase in the proportion of aggregates of high molecular weight (above 200 kDa) and B-polypeptide was observed. On addition of xanthan (0.025 and 0.05%) to protein solutions (0.5 and 2%), the formation of aggregates of high molecular weight was favoured for both NSP and DSP. In the absence of xanthan, no preferential adsorption of soy polypeptides was observed at the air–water interface of NSP foams. However in DSP foams, there was a preferential adsorption of B-polypeptides. Xanthan present in NSP foams (0.5 or 2%), caused an increase in the proportion of aggregates of high molecular weight at the interface as compared with the composition of solutions used to make the foams. An increase in proportion of AB-polypeptides (for 0.5% NSP and 0.025% xanthan) and B-polypeptides together with polypeptides of molecular weight lower than 14 kDa (for 0.5% NSP and 0.05% xanthan) was also observed at the interface in NSP foams. On the contrary, the presence of xanthan in DSP foams caused a decrease in the proportion of aggregates of high molecular weight and a concomitant increase in B-polypeptide. The B-11S polypeptide predominated the interface of DSP foams probably for its hydrophobicity and basic characteristics.     

Evaluation of the Fate of Aldicarb and Its Metabolites in Oranges

Abstract

The accumulation, persistence and fate of systemic pesticide aldicarb was melencholy evaluated in orange crops. The concentration of this pesticide and its two toxic metabolites, aldicarb sulfoxide and aldicarb sulfone was determined in leaves, rind and pulp of three orange varieties (Satsuma, Navelina and Clemetina de Nules) and in the top soil of the orange groves. The groves were located in two different places in the Valencia Community (Spain). The analysis showed that the aldicarb concentration was lower than those of aldicarb sulfoxide and aldicarb sulfone. In all cases, the residues persisted at least 160 days in vegetable samples and between 157 and 227 days in soil samples. Residue concentrations measured in the soil samples were highly variable but a relation with the organic matter content can be observed. The residue levels found in vegetal products were higher in leaves than in rind, and in rind than in pulp. The maximum residue values were obtained between 47 and 70 days after the application. One hundred days after treatment (Security period) the residue levels of total fruit were lower than the maximum residue level of 0.2 mg/kg established by law.