管式silicalite-1沸石膜的制备及表征

利用二次晶种生长法在多孔管式氧化铝载体上合成了连续、完整的silicalite-1沸石膜。通过X-射线衍射仪(XRD)和扫描电子显微镜(SEM)分析了silicalite-1沸石膜的结构及表面形貌,并通过气体渗透测试表征了沸石膜的气体渗透性能和分离效果。研究结果表明,所合成的silicalite-1沸石膜厚度为15μm,H_2的渗透率达到7.15×10^(-7)mol·m^(-2)·s^(-1)·Pa^(-1)。该沸石膜的H_2/N_2理想分离因子为3.81,H_2/SF_6理想分离因子为22.46,说明沸石膜无明显缺陷。

PERVAPORATION SEPARATION OF ETHANOL/WATER MIXTURES WITH CHLOROSILANE MODIFIED SILICALITE-1/PDMS HYBRID MEMBRANES

Ultra-fine silicalite-1 particles were modified with four kinds of chlorosilanes （dodecyltrichlorosilane, octyltrichlorosilane, hexadecyltrichlorosilane and octadecyltrichlorosilane） and characterized by FI-IR, TGA, contact angle measurements and BET analysis. It was found that the surface hydrophobicity of silicalite-1 particles was improved significantly as the alkyl group was strongly bonded to the particle surface. Modified silicalite-1 particles were incorporated into PDMS （poly（dimethylsiloxanediol）） membranes, which were applied for the pervaporation separation of ethanol/water mixtures. The effect of surface properties, zeolite loading and operation conditions on pervaporation performance of the membranes was investigated. The separation factor of PDMS membranes filled with modified silicalite-1 increased considerably compared with that filled with unmodified ones, and the total flux decreased with increasing zeolite loading. The solution and diffusion selectivity of hybrid membranes were also measured to explain the pervaporation properties of silicalite-1 filled PDMS membranes. It was found that modification of silicalite-1 with dodecyltrichlorosilane effectively improved the solution and diffusion selectivity of silicalite-1 filled PDMS membranes with high zeolite loading. This may be attributed to the high surface hydrophobicity of modified silicalite-1 and its good integration with PDMS membranes. Both the high separation factor and solution selectivity indicated that modification of silicalite-1 with chlorosilanes was an effective method to improve the selectivity of silicalite-1/PDMS hybrid membranes for ethanol.

Synthesis of Hydrophilic Acid-resistant Ge-ZSM-5 Membranes via Secondary Growth Method Using Silicalite-1 Zeolite as Seeds

Hydrophilic acid-resistant Ge-ZSM-5 membranes were synthesized via secondary growth method on porous a-A1203 substrates with Silicalite-1 zeolite as seeds. The membranes were characterized by means of scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectrometer to look into the microstructures and element contents of the membranes. The separation performance of the membranes was investigated for separating water from acetic acid solution by pervaporation. The results show that membranes fabricated by the conventional secondary growth method have a high flux, but the selectivity of them is rather limited. Preheating the secondary synthesis sol and using the supernatant as the secondary synthesis sol for membrane fabrication were found to be ef- fective to lower the concentration of the nutrient to constrain re-nucleation, at the same time, lower the A1 content in the membranes. The membrane obtained exhibited improved separation performance with a separation factor of 83 at a flux of 0.67 kg.rn-2.h-1 at 353 K for a feed concentration of 98% acetic acid solution.

Overexpression of heme oxygenase-1 protects smooth muscle cells against oxidative injury and inhibits cell proliferation

To investigate whether the expression of exogenous heme oxygenase-1 (HO-1) gene within vascular smooth muscle cells (VSMC) could protect the cells from free radical attack and inhibit cell proliferation, we established an in vitro transfection of human HO-1 gene into rat VSMC mediated by a retroviral vector. The results showed that the profound expression of HO-1 protein as well as HO activity was 1.8- and 2.0-fold increased respectively in the transfected cells compared to the non-transfected ones. The treatment of VSMC with different concentrations of H2O2 led to the remarkable cell damage as indicated by survival rate and LDH leakage. However, the resistance of the HO-1 transfected VSMC against H2O2 was significantly raised. This protective effect was dramatically diminished when the transfected VSMC were pretreated with ZnPP-IX, a specific inhibitor of HO, for 24 h. In addition, we found that the growth potential of the transfected cells was significantly inhibited directly by increased activity of HO-1, and this effect might be related to decreased phosphorylation of MAPK. These results suggest that the overexpression of introduced hHO-1 is potentially able to reduce the risk factors of atherosclerosis, partially due to its cellular protection against oxidative injury and to its inhibitory effect on cellular proliferation.

Preparation and pervaporation performance of high-quality silicalite-1 membranes

High-performance silicalite-1 membranes were successfully synthesized on novel porous silica tubes by two-step in-situ hydrothermal synthesis. The flux and separation factor towards ethanol/water mixture at 60°C were 0.56 kg/(m2·h) and 84, respectively. The as-synthesized silicalite-1 membranes were characterized by scanning electron microscopy (SEM). The influence of different synthesis conditions on the separation performance of the silicalite-1 membranes was investigated. It was found that the average flux of silicalite-1 membranes was improved by about 26% after filling the silica tubes with mixed solution containing glycerol and water. After calcinating at 400°C for 5 h repeatedly, membrane synthesized on silica tube still showed high pervaporation performance towards ethanol/water mixture even at a calcination rate of 4°C/min, which suggested that silica support was more suitable for preparing high-performance silicalite-1 membranes.

Lateral growth of silicalite-1 crystal membrane on glass slabs

ZEOLITES and molecular sieves are crystallite materials with well-defined and uniform micropore system that can recognize and discriminate molecules according to their sizes and shapes. Therefore, zeolite and molecular sieve crystals serve as host, organizing organic and inorganic guest atoms, molecules, and supramolecular compounds in their channels or cavities, which results in host-guest materials with novel properties in optical data storage, nonlinear optics, electrochemistry and optoelectronics. The general crystallite size of zeolites and

Synthesis and separation performance of silicalite-1 membranes on silica tubes

High-performance silicalite-1 membranes were synthesized on silica tubes by in-situ hydrothermal synthesis. By using the “solution-filling (SF)” method, the average flux of membranes with the SF method was improved by about 25% compared to that of the membranes without using the SF method; the flux and the separation factor of the membranes prepared with the SF method for an ethanol/water mixture at 60°C were 0.99 kg/(m2·h) and 73, respectively. It was found that the membranes synthesized on silica tubes exhibited high thermal stability and high reproducibility, and the relatively standard deviations (R.S.D.) of the average flux and separation factor were only 9.6% and 5.6%, respectively, which suggests that the silica support is more suitable than other kinds of supports for preparing high-performance silicalite-1 membranes.

Synthesis of Silicalite-1 Zeolite Membranes Under Microwave Heating

Silicalite-1 membranes supported on macroporous Al2O3 tubes were prepared by in-situ crystallization and secondary growth method under microwave-assisted closed system. The influences of crystallization time and temperature on properties of the as-prepared membranes were investigated. Results show that by in-situ crystallization at different temperatures it's hardly to obtain uniform membranes on the poor supports, while by secondary growth method dense and well-intergrown silicalite-1 membranes with thickness of 2 μm on seeded supports can be obtained even at 393 K for 60 min. At 423 K, 30 min was enough to synthesize well-intergrown and uniform zeolite membrane under microwave heating. These silicalite-1 membranes also exhibit well hydrogen permeation performance. The effect of temperature was more remarkable than that of time evaluated from the morphology difference of these membranes.

BITDS作载体的S-BLM生物传感器

合成了二硫化二（Ｎ，Ｎ－１，４－亚丁基）秋兰姆（简称 ＢＩＴＤＳ），以它为中性载体，并嵌入类脂双层膜中，制成了铂支撑的双层类脂膜生物传感器．实验结果表明，该传感器对铜离子具有好的选择性和灵敏度，线性响应范围为 １０^-5～１０^-2 ｍｏｌ／Ｌ Ｃｕ~2+，响应斜率为 ３２ ｍＶ／ｐＣ．

联萘酚与固体支撑双层类脂膜相互作用

采用循环伏安法、交流阻抗法研究了联萘酚(BINOL)与固体支撑双层类脂膜(s-BLM)之间的相互作用.结果表明,联萘酚通过氢键、疏水作用与s-BLM发生相互作用.随着相互作用时间的延长,联萘酚/s-BLM体系中的氧化峰电流先增大后减小,表明联萘酚逐渐破坏s-BLM的整体性,诱导膜内部形成微孔通道.联萘酚的浓度越大,联萘酚分子通过s-BLM的渗透时间越短.此外,随着卵磷脂浓度和胆固醇含量的增加,s-BLM的膜电阻变大,联萘酚渗透通过s-BLM速率减小,导致其对s-BLM的渗透性能减弱.

玉米醇溶蛋白导向合成b轴取向Silicalite-1担载膜

采用旋涂工艺在多孔氧化铝（α-Al2O3）基片上制备玉米醇溶蛋白（zein）膜,以预涂zein膜的Al2O3基材为载体,通过原位水热法合成了silicalite-1担载膜。结果表明：以zein膜为模板可有效导向合成优先b轴取向silicalite-1晶体,所制备silicalite-1膜层表面平整且连续性好。而在未涂覆zein膜的Al2O3基材上所合成的silicalite-1晶体呈随机取向,表面缺陷较大,需多次重复水热合成制备。渗透蒸发实验中选择有机溶剂含量为3%（质量分数）的乙醇/水和丙酮/水二元体系,考察料液温度在25-40℃范围内优先b轴取向silicalite-1担载膜对有机组分的筛分浓缩能力。实验表明,对乙醇和丙酮两组分的分离因子大小顺序为乙醇、丙酮,渗透通量的大小则刚好相反。

Transretinoic acid inhibits rats gastric epithelial dysplasia induced by N-methyi-N-nitro-N-nitrosoguanidine:influences on cell apoptosis and expression of its regulatory genes

INTRODUCTIONGastric epithelial dysplasia (GED) hypothetically is a straight-forward concept: dysplastic epithelium replacing the normal gastric epithelium of the stomach [1].In the stomach ,like any other segment of the gut ,it is defined as an unequivocal non-invasive epithelial change[2,3].The observation of gastric dysplasia as a cancerous lesion was recognized over a century ago ,but it is only after the advent of gastroscopy that its clinical significance has been stressed[4-7].

Pd/silicalite-1: An highly active catalyst for the oxidative removal of toluene

Catalytic combustion is thought as an efficient and economic pathway to remove volatile organic compounds, and its critical issue is the development of high-performance catalytic materials. In this work, we used the in situ synthesis method to prepare the silicalite-1(S-1)-supported Pd nanoparticles(NPs). It is found that the as-prepared catalysts displayed a hexagonal prism morphology and a surface area of 390-440 m^(2)/g. The sample(0.28Pd/S-1-H)derived after reduction at 500°C in 10 vol% H_(2)showed the best catalytic activity for toluene combustion(T50%= 180℃ and T90%= 189℃ at a space velocity of 40,000 m L/(g·hr), turnover frequency(TOFPd) at 160℃ = 3.46 × 10^(-3)sec^(-1), and specific reaction rate at 160℃ = 63.8μmol/(gPd·sec)), with the apparent activation energy(41 k J/mol) obtained over the bestperforming 0.28Pd/S-1-H sample being much lower than those(51-70 k J/mol) obtained over the other samples(0.28Pd/S-1-A derived from calcination at 500℃ in air, 0.26Pd/S-1-im derived from the impregnation route, and 0.27Pd/ZSM-5-H prepared after reduction at 500℃ in 10 vol% H_(2)). Furthermore, the 0.28Pd/S-1-H sample possessed good thermal stability and its partial deactivation due to CO_(2) or H_(2)O introduction was reversible, but SO_(2) addition resulted in an irreversible deactivation. The possible pathways of toluene oxidation over 0.28Pd/S-1-H was toluene → p-methylbenzoquinone → maleic anhydride, benzoic acid, benzaldehyde → carbon dioxide and water. We conclude that the good dispersion of Pd NPs, high adsorption oxygen species concentration, large toluene adsorption capacity, strong acidity,and more Pd~0 species were responsible for the good catalytic performance of 0.28Pd/S-1-H.

Effect of a cancer vaccine prepared by fusions of hepatocarcinoma cells with dendritic cells

AIM: To prepare a cancer vaccine (H(22)-DC) expressing high levels of costimulatory molecules based on fusions of hepatocarcinoma cells (H(22)) with dendritic cells (DC) of mice and to analyze the biological characteristics and induction of specific CTL activity of H(22)-DC. METHODS: DCs were isolated from murine spleen by metrizamide density gradient centrifugation, purified based on its characteristics of semi-adhesion to culture plates and FcR-,and were cultured in the medium containing GM-CSF and IL-4. A large number of DC were harvested. DCs were then fused with H(22) cells by PEG and the fusion cells were marked with CD11c MicroBeads. The H(22)-DC was sorted with Mimi MACS sorter. The techniques of cell culture, immunocytochemistry and light microscopy were also used to test the characteristics of growth and morphology of H(22)-DC in vitro. As the immunogen, H(22)-DC was inoculated subcutaneously into the right armpit of BALB/C mice, and their tumorigenicity in vivo was observed. MTT was used to test the CTL activity of murine spleen in vivo. RESULTS: DC cells isolated and generated were CD11c+ cells with irregular shape, and highly expressed CD80, CD86 and CD54 molecules. H22 cells were CD11c- cells with spherical shape and bigger volume, and did not express CD80, CD86 and CD54 molecules.H(22)-DC was CD11c+ cells with bigger volume, being spherical, flat or irregular in shape, and highly expressed CD80, CD86 and CD54 molecules, too. H(22)-DC was able to divide and proliferate in vitro, but its activity of proliferation was significantly decreased as compared with H(22) cells and its growth curve was flatter than H(22) cells. After subcutaneous inoculation over 60 days, H(22)-DC showed no tumorigenecity in mice, which was significantly different from control groups (P【0.01). The spleen CTL activity against H(22) cells in mice implanted with fresh H(22)-DC was significantly higher than control groups (P 【 0.01). CONCLUSION: H(22)-DC could significantly stimulate the specific CTL activity of murine spleen, which suggests that the fusion cells have already obtained the function of antigen presenting of parental DC and could present H(22)specific antigen which has not been identified yet, and H(22)-DC could induce antitumor immune response; although simply mixed H(22) cells with DC could stimulate the specific CTL activity which could inhibit the growth of tumor in some degree, it could not prevent the generation of tumor. It shows that the DC vaccine is likely to become a helpful approach in immunotherapy of hepatocarcinoma.

N503-煤油-KSCN分散支撑液膜体系中Pd(Ⅱ)的传输研究

以聚偏氟乙烯膜(PVDF)为支撑体,煤油为膜溶剂,N-N-二(1-甲基庚基)乙酰胺(N503)为流动载体,研究了分散支撑液膜体系中金属Pd(Ⅱ)的传输行为;考察了料液相酸度、分散相膜溶液与解析液体积比以及分散相中KSCN浓度对Pd(Ⅱ)传输的影响。结果表明,当料液相中盐酸浓度为0.10mol.L-1、分散相中膜溶液与解析液KSCN体积比为30:30、解析液KSCN浓度为1.60mol.L-1时,该分散支撑液膜体系对金属Pd(Ⅱ)具有良好的传输作用。在最佳传输条件下,Pd(Ⅱ)起始浓度为5.00×10-5mol.L-1时,130min的传输时间分散支撑液膜体系传输效率可以达到79.8%,而传统支撑液膜只有67.8%。