Characterization of Nanostructures in Acellular Cementum of Human Tooth Roots

Determining the microstructure in human cementum might help us design new kinds of replacement materials for the treatment of teeth injury and disease. The authors characterized the nanostructures in the cementum of health human teeth via scanning electronic microscopy(SEM). It was found that the acellular cementum is mainly composed of two kinds of nanostructures―inorganic nanoparticles and organic nanofibers. And the inorganic nanoparticles show a tendency to arrange along the organic nanofibers. Based on the micro-molding in capillary strategy, the distribution of organic component in acellular cementum was copied with UV curable resin. After removing the inorganic nanoparticles by acid etching, many isolated spindle shape nanopores were left in polymer, which su- ggested that the inorganic nanoparticles should have been isolated by the organic component in cementum, and should be oval or nanosheet in shape. We hope the present work could provide reference for the biomimetic preparation of tissue engineering materials, and help us design new types of tooth implant.     

新型混合导体透氧膜的制备及其在甲烷转化反应中的应用

用EDTA 柠檬酸联合络合法合成了新型混合导体透氧膜材料 ,成功地制备了致密膜片并对其透氧性能进行了考察 .结果发现 ,此新材料具有非常大的透氧能力 ,850℃时在膜一端为干燥的流动空气而另一端为流动的氦气下 ,透氧量高达 0 744μmol/(cm2 ·s) .考察了膜片本身对甲烷的活化性能 ,发现导体膜对甲烷氧化偶联具有催化活性 ,随着甲烷流速的增加 ,甲烷转化率降低 ,而C2 选择性升高 .研究了膜反应器中甲烷部分氧化制合成气反应 ,甲烷转化率约为 90 % ,CO选择性约为 98% ,CO/H2 比约为 2 ;同时 ,膜的透氧量急剧增加到约 6 0 1 μmol/(cm2 ·s) ,这归结于膜反应侧氧分压的急剧降低 .     

用规整膜板对砷化镓的三维微结构图形加工刻蚀

以微齿轮图形结构作为规整模板 ,用约束刻蚀剂层技术对GaAs样品表面进行了加工刻蚀 .在有捕捉剂H3AsO3存在的情况下 ,规则微齿轮图形能够很好地在样品表面复制 .刻蚀结果与没有捕捉剂存在时的刻蚀结果做了比较 .另外还测试了不同方法制得膜板的性能 ,初步探讨了电化学模板的制作工艺 .     

Microwave-assisted Regioselective 1-O-Deacylation of Peracylated Glycopyranoses on Alumina

A facile, rapid and regioselective method for the 1-O-deacylation of peracylated glycopyranoses is described which occurs under mild conditions by absorption onto alumina using microwave irradiation.     

Comparison of Pb, Cd Adsorption to Surface Coatings Developed in Natural Waters with that in Plant Effluents

The comparative studies of Pb and Cd adsorption to the surface coatings (Fe, Mn, AI oxides, organic materials, and associated minerals), which were developed on glass slides in five natural and two technical waters (plant effluents), were carried out under controlled |aboratory conditions(mineral salts solution with defined speciation, ionic strength 0.05 mol/L, 25 ℃ and pH 6. 0). The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Pb and Cd adsorption to the surface coat-ings. The results show that the maximum adsorption of Pb and Cd to the surface coatings mentioned above varied widely. There was a systemic increase in the maximum adsorption of Pb and Cd to the surface coatings with increasing the contents of Mn and Fe oxides in the surface coatings in significant correlation, respective-ly, not only highlighting the relative importance of the metal oxide fraction for Pb and Cd adsorption to the surface coatings developed in natural and technical water samples, but also implying the same adsorption mechanisms of Pb and Cd to the surface coatings developed both in natural and technical water samples.     

Syntheses of 3-[5-Methyl-1-(4-Methylphenyl)-1,2,3-Triazol-4-yl]-6-Substituted-s-Triazolo[3,4-b]-1,3,4-Thiadiazoles

1,2,3-Triazole derivatives have been reported as inhibiting tumor proliferation, invasion, and metastasis^[1]. The fused l,3,4-triazolo[3,4-b]-1,3,4-thiadiazoles derivatives show various biological effects such as antifungal^[2], antibacterial, hypotensive and CNS depressant activities^[3]. We have reported several 6-aryl-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[3,4-b]-1,3,4-thiadiazoles in the previous paper^[4]. The novel 6-aryl-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazolo[2,4-b]-1,3,4-thiadiazoles 6a-j have been synthesized by the condensation of 4-amino-5-mercapto-3-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-s-triazole 5 with various aromatic carboxylic acids in the presence of phosphorus oxychloride. The mercaptotriazole 5 was prepared from 4,the latter being prepared from 1 throng 2 and 3. The title compounds 6 were depicted in scheme 1. The structures of these compounds were established by elemental analysis, NMR, MS and IR techniques.     

一种新的液晶高分子——丁酸壳聚糖的合成与表征

甲壳素几乎不溶于任何溶剂,由于其脱乙酰化产物壳聚糖含自由氨基,能被酸质子化而溶解,所以壳聚糖的应用领域远多于甲壳素.但是壳聚糖也仅能溶于酸性介质中,并不能溶于纯水和普通有机溶剂,因而人们对甲壳素或壳聚糖进行各种化学改性[1,2],寻求溶解性更好尤其能溶于水的衍生物,以扩大其应用范围.本文按文献[2～4]方法合成了O-丁酰化壳聚糖(简称丁酸壳聚糖),首次报道它具有溶致液晶性.     

耐高温α-淀粉酶结合Ca2+的研究

测定了耐高温α-淀粉酶分子中含10个Ca2+,脱钙酶逐量补钙后的活力及稳定性研究表明:酶分子中前8个Ca2+参与酶的催化作用,后2个Ca2+抖对酶结构起稳定作用.脱钙酶加钙后室温下的荧光光谱和CD谱表明:酶的构象虽有变化,但不显著,说明酶的构象对ca2+的依赖性很小.脱钙酶结合不同数目的Ca2+,于90℃加热15 min后,测其荧光光谱,结果表明,结合10个Ca2+时,酶保持最大的稳定构象;CD谱表明脱钙酶加热时仍具有一定的螺旋结构.这再次说明,酶的构象对ca2+依赖性较低.     

The Electrochemistry of Cytochrome c at a Viologen-thiol Self-Assembled Monolayer

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典型钙/镁基吸附剂对二氧化硒吸附特性研究

针对钙/镁基矿物吸附剂的主要组分CaO、CaCO₃、MgO在500-800 ℃下对Se的吸附特性进行研究，并选取天然矿物方解石、白云石研究其对Se的吸附效果，且对矿物煅烧所得CaO进行吸附实验。结果表明，三种组分中CaO的吸附效果最佳，800 ℃时单位质量CaO对Se的吸附量可达368 mg/g。CaCO₃对Se的吸附在700 ℃时效果最佳且其吸附产物的热稳定性较好。镁基吸附剂仅在中温段对Se具有一定吸附效果。方解石对Se的吸附效果随温度变化趋势与CaCO₃相似，因其较好的孔隙结构，吸附效果略优于CaCO₃。煅烧方解石得到的F-sor对Se的吸附效果优于CaO和CaCO₃煅烧得到的C-sor，这与其良好的比表面积、孔隙结构与抗烧结能力有关，且F-sor吸附产物的热稳定性相对较好。F-sor对Se的吸附量最高可达403 mg/g。