Detection of DNA damaging agents using layer-by-layer assembly

The layer-by-layer (LBL) electrostatic deposition method was used to fabricate multilayer films of pentaerythritol-based metallodendrimer with Ru^II terpyridine subunits (RuDen) that has a positive charge and ds-DNA (ds, double-stranded) that has a negative charge due to its phosphate backbone. Evidence of assembly was obtained by fabrication of (DNA | RuDen)_n on quartz treated with poly(diallyldimethylammonium chloride), PDDA. The absorbance at 263 nm varied linearly with n in the range 1-6. For electrochemical monitoring of damage by styrene oxide, the assembly was on a glassy carbon electrode that was coated with a monolayer of aminobenzoic acid. The measurement was based upon the RuDen-catalyzed oxidation of sites, e.g. guanine, that are exposed when ds-DNA is damaged. The peak current at 1.07 V versus Ag | AgCl in square wave voltammetry increases with incubation time for 30 min. The process was also monitored by the shift in the spectrum of a long period grating (LPG) fiber coated with (DNA | RuDen)₅. A typical shift, which is due to changes in the refractive index of the coating, was 0.3 and 1.8 nm for 5 and 30 min exposures, respectively, using an algorithm that can measure a shift of 10⁻⁴ nm.     

Long pathlength, three-dimensional absorbance microchip

A long pathlength, three-dimensional U-type flow cell was microfabricated and evaluated for improved absorbance detection on a glass microdevice. A small diameter hole (75 μm) was laser etched in a thin glass substrate whose thickness (100 μm) defined much of the pathlength of the cell. This substrate was thermally bonded and sandwiched between two different glass substrates. The top substrate contained a typical injection cross and separation microchannel. Projecting out of the plane of the separation device was a 126 μm pathlength flow cell as defined by the laser etched hole and the attached microchannels. The flow cell was connected to a microchannel on the bottom substrate that led to a waste reservoir. The planar, flat windows on the top and bottom of this device made light introduction and collection a simple matter using a light emitting diode (LED) and microscope objective. The experimentally obtained detection limit for rhodamine B was determined to be 0.95 μM, which is nearly identical to the theoretical limit calculated by Beer's Law. A separation of three fluorescent dyes was performed, and direct comparisons were made between the transmittance changes through the narrow pathlength separation microchannel and the adjacent long pathlength, three-dimensional U-type flow cell.     

GC／MS法分析鳗鱼骨油的脂肪酸

用乙醚／已烷混合溶剂抽提鳗鱼骨油，用ＫＯＨ－ＣＨ_３ＯＨ酯交换法甲酯化，以毛细管色谱／质谱方法测定脂肪酸的组成。共检出２７种脂肪酸，其中以棕榈油酸、棕榈酸、油酸、硬脂酸、花生烯酸为主。     

古人类骨骼中微量元素的分析及其与古代食谱的关联

采用等离子体质谱(ICP-Ms)法对三峡地区及长江下游地区出土的古墓中的人体骨骼中的微量元素Zn、Sr、Ba、Ca进行了分析，并与原子吸收光谱(AAS)对照，结果表明：ICP-MS是骨化学微量元素分析很好的方法，它相对FAAS，具有灵敏度高，检出限低，可快速进行多元素检测等优点，对溶液中元素的检出限可达到ng/L数量级，对元素的高含量和低含量都能进行准确测量。本实验以Zn、Sr、Ba、Ca为指示剂，根据其测量结果，还对上述两地区的古人类食谱进行了初步探讨。     

A novel injectable poly(epsilon-caprolactone)/calcium sulfate system for bone regeneration: synthesis and characterization

A novel poly(epsilon-caprolactone)/calcium sulfate system was prepared and characterized in order to enhance calcium sulfate (gypsum) performance as bone graft substitute overcoming its brittleness and fast resorption rate. A poly(epsilon-caprolactone) (PCL) photo-crosslinkable derivative (PCLf) was synthesized by reaction of a low molecular weight PCL diol with methacryloyl chloride and confirmed by FT-IR and 1H NMR analyses. An injectable and easy mouldable mixture of PCLf and calcium sulfate hemi-hydrate (PCLf/CHS) was obtained. Thermal analyses and solvent extraction proved the occurrence of PCLf photo-crosslinking, even in the presence of CHS, in a time suitable for clinical applications. Swelling studies demonstrated that the encapsulation of the inorganic filler increases network hydrophilicity making it more permeable to water. Scanning electron microscopy, performed on crosslinked PCLf/CHS and on the same material after incubation in a PBS solution, showed the feasibility to obtain, in situ, gypsum entrapped into a degradable polymeric network. In vitro cytotoxicity tests, performed according to ISO 10993-5, proved that the developed system was not cytotoxic supporting its potential use in tissue engineering as a new, injectable, photocurable bone graft material. SEM micrograph of calcium sulfate di-hydrate (gypsum) entrapped in the PCL network.     

长程范德华力导向作用下胶体凝聚的计算机模拟

采用计算机模拟方法研究了长程范德华力在胶体凝聚过程中的作用, 发现由于胶粒间的范德华力是长程力, 它对胶粒或团簇运动将产生导向作用. 与不考虑导向作用的扩散控制团簇凝聚(DLCA)模型比较, 这种导向作用不仅加速了胶体的凝聚过程, 而且形成了更致密、分形维数更大的结构体. 研究还发现, 长程范德华力导向作用对胶粒的初始浓度非常敏感, 不论是在凝聚物的结构还是凝聚速率方面, 只有在胶粒初始浓度较低时, 该导向作用效应才明显. 其可能的原因是,在胶粒初始浓度较高时, 由于胶粒布朗运动的平均自由程很短而且位阻效应大, 从而使导向作用效应未能反映出来.     

高氟铝暨铝引起性发育前人和动物高钙及高骨矿性骨软化

对铝氟联合中毒27例2－11岁儿童和100日龄雄鸡实验3个月进行了动态观察。结果表明，骨软化伴 骨硬化的病人有22例，占81％；随着年龄增长，骨硬化渐渐突出；患儿全血钙、磷升高，血清Ca^2 正常范围偏高，血清P^5 下降。铝氟联合作用实验鸡性发育前、后全血钙一直较高，全血磷与血清Ca^2 、P^5 及其相关关系出现由高到低到高的交错变化；单独铝作用全血钙一直较高，碱到性成熟期下降，血清Ca^2 、P^5 一直较低。在性发育完成阶段，高铝可使类骨质矿化过度延迟，小幅度减少骨钙、磷含量，但骨部矿物元素和骨矿含量及骨密度不一定降低，甚至可小幅度升高，又有同软化；铝氟联合作用时类骨质矿化延迟时间仍过长，骨矿沉积率已高于对照，存在明显分离。氟可提高矿物元素含量，使骨矿化与骨硬化在骨组织不同层面茯结合成年病人的情况，认为铝氟联合 作用骨损害的表现与骨代谢速度及细胞生物化学和物理化学骨形成方式偏转的变化密切相关。     

Supramolecular Assembly of Triangulo Pd(II) Diimine Complexes Containing Triply‐Bridging Sulfide Ligands

We report here a substituent effect of diimines on the solid‐state assembly of interesting triangulo Pd(II) complexes, [(Pd(d‐t‐bpy))₃(μJ₃‐S)₂][NO₃]₂ 1 ·[NO₃]₂ and [(Pd(bpy))₃(μ₃‐S)₂][ClO₄]₂ 2 ·[ClO₄]₂ (d‐t‐bpy = 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine, bpy = 2,2′‐bipyridine). 2 ·[ClO₄]₂ shows the intermolecular π···π interactions leading to the formation of one‐dimensional frameworks, whereas 1 ·[NO₃]₂ only shows the discrete structure in the solid state, featuring an interesting herring‐bone arrangement. The variation in structural motifs from 1 ·[NO₃]₂ to 2 ·[ClO₄]₂ is expected to be dominated by the substituent's steric hindrance for the diimine ligand. Thus, the crystal‐engineering approach has proved successful in the solid‐state packing due to a substituent's modification of the diimine ligand.     

去卵巢大鼠骨基质明胶修复骨缺损骨痂的矿物质元素分析

应用等离子体发射光谱仪测定了去卵巢水平下骨基质明胶修复大鼠颅骨骨缺损新生骨痂的矿物质元素含量。将28只雌性SD大鼠随机分为2组。去卵巢组切除双侧卵巢，伪手术对照组保留卵巢。术后4周在颅骨上制备骨缺损并同期植入骨基质明胶。8周后，测定新生骨痂的矿物质元素含量。结果显示，去卵巢大鼠新生骨痂的S、Ca、P、Zn、Fe和Cu含量较伪手术组显著降低。实验表明雌激素水平影响骨基质明胶修复骨缺损骨痂的矿物质元素含量。     

白血病骨髓移植患者口腔黏膜病与微量元素锌的关系

为研究白血病骨髓移植患者全血微量元素锌与口腔黏膜病的关系，用原子吸收光谱法检测了正常对照组与白血病骨髓移患者预处理前及移植后骨髓空虚期全血微量元素锌的含量，并观察了白血病骨髓移植患者空黏膜病变情况。结果表明，正常对照组全血锌浓度与白血病骨髓移植患者预处理前全血锌浓度比较，差异无显著性（P＞0．05），而预处理前全血锌浓度与骨髓空虚期全血锌浓度有显著性差异（P＜0．01），白血病缓解后（预处理前）血锌接受正常水平，无口腔溃疡发生，而白血病骨髓移植患者处理后骨髓空虚期全血锌含量显著降低，并出现不同程度的口腔黏膜病变，说明预处理影响微量元素锌的代谢，微量元素锌的减少与白血病骨髓移植患者移植患者口腔黏膜病的发生有关。