A New Route for Preparation of β-TCP/PLLA Composite

Bone tissue engineering offers a promising route to repair and replace damaged or diseased tissues in the cases including trauma, congenital and degenerative diseases, cancer, and so on. Polylactic acid(PLLA)-based materials showing bioresorbability are u…     

PLLA/β-TCP杂化微纳米纤维的制备及其性能

将湿法工艺合成的β-磷酸钙纳米粒子与左旋聚乳酸(PLLA)的混合溶液通过电纺丝法制成杂化纳米纤维膜,以期制备一种新型纳米纤维骨组织修复材料。采用FT-IR,XRD,TEM,DSC等手段研究了β-磷酸钙(β-TCP)的结构和形态,采用SEM和直径分布探讨了优化PLLA/β-TCP纤维的电纺丝工艺。结果表明:采用湿法合成β-TCP的纳米粒子具有良好的晶型结构,直径在219~328 nm之间;采用双溶剂体系在优化条件下制备的PLLA/β-TCP杂化纳米纤维直径在500~700 nm之间,PLLA/β-TCP界面结合良好,β-TCP起到了增强作用。在湿态条件下,PLLA纤维膜的力学性能有所提高,而PLLA/β-TCP纤维膜的力学性能则呈现下降趋势。     

高效液相色谱法同时测定土壤中毒死蜱残留及其有毒代谢物3,5,6-TCP

通过对色谱分离条件优化、提取体系建立和固相色谱小柱筛选,建立了用弗罗里硅土固相萃取小柱净化高效液相色谱法同时测定土壤中毒死蜱农药残留及其有毒代谢物3,5,6-TCP.方法加标回收率在59％～87％之间,检测限为0.0005～0.03 μg/g,日内回收率标准偏差RSD≤4.3％,日间回收率标准偏差RSD≤4.9％,方法...     

Adsorption separation of carbon dioxide, methane, and nitrogen on Hβ and Na-exchanged β-zeolite

Adsorption isotherms of carbon dioxide (CO2), methane (CH4), and nitrogen (N2) on Hβ and sodium exchanged β-zeolite (Naβ) were volumetrically measured at 273 and 303 K. The results show that all isotherms were of Brunauer type Ⅰ and well correlated with Langmuir-Freundlich model. After sodium ions exchange, the adsorption amounts of three adsorbates increased, while the increase magnitude of CO2 adsorption capacity was much higher than that of CH4 and N2. The selectivities of CO2 over CH4 and CO2 over N2 enhanced after sodium exchange. Also, the initial heat of adsorption data implied a stronger interaction of CO2 molecules with Na+ ions in Naβ. These results can be attributed to the larger electrostatic interaction of CO2 with extraframework cations in zeolites. However, Naβ showed a decrease in the selectivity of CH4 over N2, which can be ascribed to the moderate affinity of N2 with Naβ. The variation of isosteric heats of adsorption as a function of loading indicates that the adsorption of CO2 in Naβ presents an energetically heterogeneous profile. On the contrary, the adsorption of CH4 was found to be essentially homogeneous, which suggests the dispersion interaction between CH4 and lattice oxygen atoms, and such interaction does not depend on the exchangeable cations of zeolite.     

A new iridoid glycoside from Paederia scandens

<正>A new glycoside named 6β-O-β-D-glucosylpaederosidic acid(1) was isolated from Paederia scandens and its structure was elucidated on the basis of spectroscopic and chemical evidence,together with four known iridoids,paederoside(2),paederosidic acid(3),paederosidic acid methyl ester(4),and deacetyl asperulosidic acid methyl ester(5).Compound 5 was isolated from this plant for the first time.     

The design and synthesis of a novel organophosphorus compound containing the structure of both β-amino acid and β-aminophosphonate

<正>A novel organophosphorus compound containing the structure of bothβ-amino acid andβ-aminophosphonate is designed and synthesized.Arbuzov reaction with P(OEt)_3,the N-Boc protected iodide 3 cannot provide the desired product but 2-oxazolidinone 4 because of the neighboring-group participation of the Boc moiety.To avoid the intramolecular participation of the carbamates,the Ts protecting group is employed and the Ts-protected iodide 5 affords the target product successfully.     

β-Cyclodextrin promoted oxidation of aldehydes to carboxylic acids in water

A facile,efficient and substrate-selective oxidation of aldehydes to carboxylic acids with NaClO catalyzed byβ-cyclodextrin in water has been developed.A series of aldehydes which could form inclusion complex withβ-cyclodextrin(β-CD)were oxidized selectively with excellent yields.     

β-Sialon及其复合材料热力学与合成

本文对β-Sialon及其复合材料合成进行了热力学分析,采用金属还原氮化法一步制备合成了不同温度、不同Z值的β-Sialon以及β-Sialon-SiC与β-Sislon-Al2O3复合材料,XRD和SEM分析表明,以Si、Al、Al2O3和Si、Al2O3粉末为原料,用Si3N4做埋粉,在高温、常压下都可以合成较纯的β-sialon.通过改变Z值和控制烧结温度等试验发现,当Z=0.6、温度T=1450口时合成的β-sialon杂质相最少.在一定温度下,控制适宜的工艺条件,随着Z值增加,β-sialon结构由晶粒间析出部分晶须转变为明显棒状交织结构,从而可望大幅度提高其强度.     

A new approach to the synthesis of N-monosubstituted aniline and its derivatives via β-cyclodextrin host-guest complexes

A novel method for the synthesis of N-monosubstituted aniline and its derivatives β-cyclodextrin(CD)host-guest complexes has been presented.The mild reaction gives the title compounds with high selectivity in good yields of 90-98%.     

DCC/DMAP mediated esterification of hydroxy and non-hydroxy olefinic fatty acids with β-sitosterol:In vitro antimicrobial activity

<正>A new series of fatty alkenoates were synthesized using an appropriate synthetic route involving DCC and DMAP as catalysts. Compounds were characterized by their spectral data.All the synthesized compounds were evaluated for their in vitro antimicrobial activity.The minimum inhibitory concentration(MIC),minimum bacterial concentration(MBC) and minimum fungicidal concentration(MFC) were determined for test compounds as well as for reference standards.Among the compounds tested, compounds having hydroxy group at the fatty acid chain showed the most potent antibacterial as well as antifungal activities.     

N-Substituted benzoxazolyl ureas and thioureas in Biginelli reaction promoted by trifluoromethane sulfonic acid:An efficient and convenient synthesis of substituted benzoxazolyl 3,4-dihydropyrimidine(1H)-(thio)-ones

An efficient synthesis of 3,4-dihydropyrimidine 2(1H)-ones and thiones(3,4-DHPMs) core was prepared by one-pot threecomponent Biginelli condensation and which was catalyzed by trifluoromethane sulfonic acid.The classical Bignelli reaction has been extended by the use of N-substituted benzoxazolyl semicarbazides and thiosemicarbazides and this method has the advantage of excellent yields and short reaction times.     

Acidity effects of Hβ zeolite on olefin alkylation of thiophenic sulfur in gasoline

Olefin alkylation of thiophenic sulfur process was carried out in model gasoline, using Hβ zeolites with different Si/Al2 ratios as catalysts. In particular, the influence of acid properties of Hβ zeolites on its catalytic ability for the thiophene alkylation, xylene alkylation and hexene oligomerization was investigated. The results showed that the acidity of the Hβ zeolite was increased with the decrease of Si/Al2 ratio, but its catalytic ability was not always increased. In fact, it reached the maximal catalytic ability at Si/Al2 ratio of 66, and under the reaction conditions of 60 ℃, 1.5 MPa, WHSV 3.0 h-1and time on stream 2 h. At the ratio, the conversion of thiophene, xylene, and oligomerized hexene were 96.6%, 2.7% and 2.8%, respectively. An optimal Si/Al2 ratio exists for the catalytic performance of H/3 zeolite. By investigating the coke deposition of the used H/3 zeolite catalysts, it has been found that the optimal Si/Al2 ratio is attributed to the combined effect of the carbocation activation capability and the hydrogen transformation capability of the H/3 zeolite catalyst.     

Photoinitiated Reaction of β-Bromonaphthalene with Pinacolone Ion in DMSO

The radical nucleophilic substitution reaction (SRN1) has been studied widely. The reaction has constituted an important synthetic possibility to achieve substitution of different substrates with different nucleophiles1-3. The main steps of the reaction process are presented in Scheme 1.Scheme 1. Pinacolone enolate ions are widely used as nucleophiles within SRN1reaction 4-6 because it can introduce six carbon atoms into substitution products. In the paper, the photoinitiated reaction of …     

A Computational Study on Water-assisted Ammonolysis of N-Methyl β-Sultam

The ring opening of β-sultam via an H2O-assisted ammonolysis process was studied by using Density Functional Theory(DFT) method at the B3LYP/6-31G* level as a further step in the theoretical investigation of the ammonolysis reaction of β-sultams. The calculated pathways are analogous to those previously described for the non-assisted ammonolysis reaction. Solvent effects were assessed by using the polarized continuum model(PCM) method. The results show that mode 1 and pathway a in channel Ⅱ are the most favorable ones in both the cases. The energy barrier of the cleavage of C-S bonds producing P1 is the highest among all the energy barriers. The presence of a solvent in the continuum model disfavors the reaction, whereas the participation of water in the ammonolysis reaction plays a positive role and reduces the active energy greatly. The relative energies of all the transition states in the assisted ammonolysis are 20-80 kJ/mol lower than those for the non-assisted reaction.     

The protection effect of β-CD on DNA damage induced by ultrafine TiO2

Under the photocatalysis of 365 nm ultraviolet radiation, ultrafine TiO2 caused the oxidative damage of Teasy plasmid DNA. The damage was determined by gel-electrophoresis. Then, a different dose of β-CD was added to the reaction, and the damage was restrained. The rate of damage restraining reached 97% when the mass of β-CD was 4 times as that of TiO2. Through UV scan and IR spectroscopy, it was found that the Ti-O of ultrafine TiO2 was bound with -OH of β-CD cavum and the -OH on the surface of ultrafine TiO2 disappeared, so the formation of · OH was controlled. The ultrafine TiO2 has been widely used, but it was determined to be carcinogenic by some research. The protection effect of β-CD to DNA in the molecular level takes a new look on the surface modification of nano particles to decrease the toxic effect.     

Reaction of carotenoids with CCl_3OO~· by using pulse radiolysis

CCl4 as a selective toxin to liver can be metabolized into the free radical 3CClg by cyto- chrome P450 through a reductive dehalogenation. In the presence of oxygen, 3CClg reacts rapidly with O2 to form CCl3OO·[1], which reacts with various biological molecules, including DNA bases, amino acids and lipids and leads to various types of tissue injury[2]. CCl3OO· is used as a model of alkyl peroxyl radicals because it can be generated in water/alcohol solution, in which sufficient solubi…     

葡萄糖苷特异性固相萃取固定相的合成、表征及应用

以马来酰亚胺基修饰凝胶载体,通过β-葡萄糖胺和2-亚氨基硫代烷盐酸盐将作为配基的β-葡萄糖脒连接到载体上,合成了一种葡萄糖苷特异性固相萃取固定相,并对其固相萃取性能进行了表征.该固定相对葡萄糖苷具有特异性识别,并成功用于固相萃取分离葡萄糖苷.     

Silica-bonded S-sulfonic acid a recyclable catalyst for the synthesis of coumarins

Silica-bonded S-sulfonic acid(SBSSA) was prepared by the reaction of 3-mercaptopropylsilica(MPS) and chlorosulfonic acid in chloroform.This solid acid has been employed as a recyclable catalyst for the synthesis of coumarins from phenols andβ-ketoesters at 80℃under solvent-free conditions.     

Copper-mediated 1,4-conjugation reaction of functionalized alkylzinc iodides with derivatives of β-nitrostyrene

Functionalized alkylzinc iodides will undergo 1,4-conjugation reaction with derivatives of β-nitrostyrene in the presence of Cu(OAc)₂/LiCl to afford a polyfunctional nitro-compound in high yield.