血管紧张素转化酶活性抑制剂──丝素肽的分离、纯化和结构鉴定

可溶性丝素粉末经碱性蛋白酶Alcalase水解后 ,其酶解产物对血管紧张素转化酶 (ACE)的活性有很强的抑制作用。采用凝胶过滤色谱SephadexG 15和反相高效液相色谱 (RP HPLC)对水解度为 2 0 %的酶解产物进行分离纯化 ,利用质谱鉴定其中一种ACE抑制剂是肽 ,其结构为Gly Tyr。

复合药剂高效处理焦炭塔吹气冷却废水

采用活性转化剂、高效分散剂、聚凝剂Ⅱ等三种药剂处理延迟焦化装置焦炭塔吹气冷却废水。在进水COD、SS、油、硫化物平均浓度分别为107 563、900、190 488、967.7 mg/L时,出水分别为872、128、129、224.7 mg/L,去除率分别达95.0%、89.6%、97.1%、69.1%。出水水质优于切焦水及冷焦水的用水标准,已回用于切焦水及冷焦水系统,为企业带来了显著的经济及环境效益。

延迟焦化废水处理的研究

介绍了活性转化剂、高效分散剂、聚凝剂Ⅱ与焦化废水的反应机理及处理焦化废水工艺。通过工业试验,确定了药剂的种类、配比和最佳投入量以及污水中污染物的去除率。

延迟焦化装置污水治理及工业应用

介绍了活性转化剂、高效分散剂、聚凝剂II与焦化废水的反应机理及焦化废水处理工艺,通过工业试验确定了药剂的最佳用量。工业应用结果表明,该工艺对延迟焦化装置放空冷却塔塔顶的污水处理效果较好,油、水、废渣分离明显,且处理效果稳定,硫化物去除率为76.8%,化学需氧量(COD)平均去除率为99.2%,悬浮物(SS)去除率为85.8%,油类去除率为99.9%,处理后的污水各项指标均达到公司污水排放标准,合格率达100%。用该工艺处理污水的成本为34.26元/t;同时还可回收污油3 t/d,创造效益194.12万元/a。

延迟焦化装置污水治理及工业应用

介绍了活性转化剂、高效分散剂、聚凝剂Ⅱ与焦化废水的反应机理及处理焦化废水工艺,通过工业试验,确定了药剂的最佳投入量以及污水中污染物的去除率及工业应用效果。结果表明,该工艺对延迟焦化装置放空冷却塔塔顶的污水处理效果较好,油、水、废渣分离明显,且处理效果稳定。工业应用中的处理效果为:硫化物去除率76.8%;化学需氧量(COD)平均去除率99.2%;悬浮物(SS)去除率85.8%,油类去除率99.9%,处理后的污水各项指标均达到兰州石化公司污水排放标准,合格率达100%;用该工艺处理污水的成本为34.26元/t,同时每日还可回收污油3 t,年创效益194.12万元。

延迟焦化装置废水预处理研究及应用

采用活性转化剂、高效分散剂、聚凝剂Ⅱ组成的复合药剂对1.2 Mt/a延迟焦化装置废水进行预处理研究。工业应用结果表明:使用该复合药剂处理焦化废水,可使废水中COD(化学需氧量)、石油类、SS(悬浮物)和硫化物的平均脱除率分别达到99.3%,99.9%,86.8%,76.8%,确保了污水处理场的稳定运行和达标排放。

ERK1/2 contributes negative regulation to STAT3 activity in HSS-transfected HepG2 cells

Signal transducer and activator of transcription 3 (STAT3) is a recently characterized transcription factor which is essential to liver regeneration. We have previously reported that hepatic stimulator substance (HSS), a novel growthpromoting substance, phosphorylated the epidermal growth factor (EGF) receptors and activated downstream RasMAP kinase (extracellular signal-regulated kinases, ERK1/2) cascade. However, whether HSS signal is related to STAT3pathway remains unclear. The present study is aiming to explore the regulatory effect of activation of ERK1/2 evoked by HSS on STAT3 phosphorylation and STAT3 signaling. Human hepatoma cell line HepG2 was stably transfected with HSS cDNA and HSS expression was measured by Northern blot. The results showed that the transfection of HSS into HepG2 resulted in remarkable increase in cellular proliferation as compared with the non-transfected cells, and it was further proved that the cellular proliferation in the HSS-transfected cells was related to ERK1/2 activation. Treatment of the cells with 50 μM of PD98059, an ERK1/2 specific upstream inhibitor, resulted in ERK1/2 inactivation completely.Inhibition of ERK1/2 allowed the tyrosine of STAT3 to be phosphorylated in a dose-dependent manner to PD98059.Furthermore, transient transfection of STAT3 mutant (STAT3S727A) into HSS-bearing cells could remarkably reverse the inhibitory effect of ERK1/2 on STAT3 phosphorylation. Based upon these results, it is concluded that ERK1/2negatively modulates STAT3 phosphorylation and this function is dependent on residual serine-727 (S727) of STAT3.

Synthesis, characterization and bioactivity evaluation of diallyl disulfide

Diallyl disulfide was synthesized by phase transfer catalyst （PTC） during microwave irradiation. The effects of different factors, such as the power of microwave irradiation, the time of microwave irradiation, PTC reagents amount and the mole ratio of reactants, on the yield of product were investigated. The structure of diallyl disulfide was characterized by infrared spectra, mass spectra and ^1 H nuclear magnetic resonance. The bioactivity of diallyl disulfide was evaluated by cell viability assay on HepG2 hepatoma cells. The results show that the optimal reaction conditions are as follows： tetrabutylammonium bromide（TBAB） selected as a PTC, the mass ratio of TBAB to sodium disulfide of 0.021 ： 1, the power of irradiation of 195 W, the reaction time of 12 rain, and the mole ratio of sodium disulfide to allyl chloride of 0.65 ： 1. The yield of diallyl disulfide is 82.2%. The synthetical diallyl disulfide appears to be cytotoxic to HepG2 heoatoma cells in a dose-dependent manner.

Facile synthesis of Zn_2GeO_4 nanorods toward improved photocatalytic reduction of CO_2 into renewable hydrocarbon fuel

Zn2GeO4 nanorods were prepared by a surfactant-assisted solution phase route.The as-prepared products were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),inductively coupled plasma atomic emission spectrometer(ICP-AES),UV-vis diffuse reflection spectroscopy and photoluminescence(PL) spectroscopy.The possible formation mechanism of Zn2GeO4 nanorods was discussed.It was supposed that the CTA+ cations preferentially adsorb on the planes of Zn2GeO4 nanorods,leading to preferential growth along the c-axis to form the Zn2GeO4 rods with larger aspect ratio and higher surface area,which showed the improved photocatalytic activity for photoreduction of CO2.The photoluminescence(PL) property of Zn2GeO4 nanorods was investigated through the emission spectra.

Effects of Surfactant on Solubility and Microbial Conversion of Steroid

Enhancing the dispersion and dissolution of substrate particles in substrate water suspension is a feasible way to improve steroid bioconversion. The aim of the present study is to investigate the effects of applying surfactant to microbial conversion system on the dispersion, solubilization and in turn bioconversion of steroid substrate. The model system is hydroxylation of substrate 19α- 17α-epoxy- 4-pregnene- 3.2It-dine by microbial enzymes from Rhizopus nigricanl. The results show that the presence of substrate leads to an increase in critical micelle concentration （ CMC） of surfactant PSE compared with the normal CMC of PSE in aqueous solution. The grinding time during substrate suspension preparation affects the substrate aqueous solubility differently with the varied surfactant concentrations while barely making any difference in substrate solubility in the absence of surfactant. The properly prolonged grinding time can make up for the loss in substrate solubility arising from the reduction in surfactant concentration. The surfactant complexes composed of surfactants PSE and MGE at appropriate ratios are screened out with orthodoxy experiment method. the interaction between PSE and MGE exerts the most prominent effects on substrate bioconversion, and the surfactant complexes show more beneficial effects on steroid bioconversion than the surfactant PSE used alone.

Conversion of n-Pentanol and n-Butanol over Cu/AC Catalyst

It is already well known that availability of petroleum oil, as a world energy source, is running low. Much work has been done by experts to produce renewable energy, especially using vegetable oil as a raw material. Accordingly, this paper presents preparation and activity test of Cu catalyst using coconut shell activated carbon （AC） as a support, for conversion of n-pentanol and n-butanol to their alkenes as the first step of conversion of ethanol to biogasoline. This conversion is interesting due to any agriculture product containing sugar or starch can be converted to ethanol. Activated carbon was used as a catalyst support because this material is inert; hence, it would not yield unexpected side product, and pollution of environment with the used catalyst can be prevented because the used catalytic metal can easily be recovered. Results of the work showed that coconut shell carbon contained some metals, which disturbed in preparation catalyst by cation exchange process. Washing the carbon with ammonium acetate or HCI solution could reduce the metals content more compared to using water, with optimum concentration for ammonium acetate solution was 1.25 M. Application of Cu/AC in converting n-pentanol and n-butanol, based on qualitative analysis to the products using GLC, GC-MS, and FTIR, when n-pentanol and nitrogen gas were flowed into a reactor filled with Cu/AC catalyst, it could be converted to n-pentene with 200 ℃ as the optimal temperature. While when n-butanol and nitrogen gas were flowed into a reactor filled with more Cu/AC catalyst, the product was supposed to contain its aldehyde and butyl vinyl ether.

Qingnaoyizhi decoction suppresses the formation of glial fibrillary acidic protein-positive cells in cultured neural stem cells by inhibiting the Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway

OBJECTIVE: Inactivation of the Janus kinase 2(JAK2)/signal transducer and activator of transcription 3(STAT3) signaling axis plays a crucial role in determining the fate of neural stem cells(NSCs).Qingnaoyizhi decoction(QNYZD) has been used for the treatment of vascular dementia and has shown to improve synaptic remodeling. The aim of this study was to evaluate the effect of cerebrospinal fluid(CSF) containing QNYZD(CSF-QNYZD) on the differentiation of cultured NSCs and the involvement of the JAK2/STAT3 pathway.METHODS: The protein expression levels of glial fibrillary acidic protein(GFAP), tubulin, drosophila mothers against decapentaplegic protein(SMAD-1), STAT3, and phosphorylated-STAT3 were detected by western immunoblot analysis in the groups: control, CSF, JAK/STAT inhibitor(AG490),CSF-QNYZD, and CSF-XDZ(CSF-Xidezhen). The differentiation of NSCs was determined by immunofluorescence staining. The proliferation of NSCs was measured using the Cell Counting Kit-8 proliferation assay.RESULTS: Compared with the control group,CSF-QNYZD and AG490 significantly increased the number and expression of tubulin-positive cells, reduced the number and expression of GFAP-positive cells, and down-regulated the expression of p-STAT3. However, CSF-QNYZD also decreased the expression of SMAD-1 and STAT3.CONCLUSION: Enhanced neuronal differentiation may be associated with the down-regulation of glial differentiation instead of promoting proliferationin treated NSCs. Furthermore, QNYZD may play a direct role in suppressing the formation of GFAP-positive cells and enhancing neuronal differentiation by inhibiting JAK2/STAT3 activation. Overall, these results provide insights into the possible mechanism underlying QNYZD-mediated neurogenesis.

Synthesis of Ag@Cu_2O core-shell metal-semiconductor nanoparticles and conversion to Ag@Cu core-shell bimetallic nanoparticles

Ag@Cu2O core-shell metal-semiconductor nanoparticles(NPs) were prepared by using solution phase strategy. It was found that Ag@Cu2O core-shell NPs were easily converted to Ag@Cu bimetallic core-shell NPs with the help of surfactant PVP and excessive reducer ascorbic acid in air at room temperature, which is a unique phenomenon. Varying volumes of Ag colloidal solutions were added into the reaction mixtures containing fixed initial concentrations of Cu2+ and PVP, Ag@Cu2O and Ag@Cu core-shell NPs with fixed core size but varying outer shell thicknesses could be obtained. The composites, structures, morphologies and extinction properties of Ag@Cu2O and Ag@Cu core-shell NPs were systematically characterized by XRD, TEM and extinction spectra. Both of these NPs show wide tunable optical properties. The extinction peaks could be shifted from 421 nm to 700 nm. FTIR results reveal that Cu+ ions on the surface of Cu2 O nanocrystalline coordinate with N and O atoms in PVP and further are reduced to metallic Cu by excessive ascorbic acid and then form a nucleation site on the surface of Cu2 O nanocrystalline. PVP binds onto a different site to proceed with the reduction until all the Cu sources in Cu2 O NPs are completely assumed. And the shell of Cu2 O is converted to Cu shell. The synthesis approach in this paper is simple and also a promising reference for synthesizing other core-shell NPs. Ag@Cu2O NPs can be easily converted to Ag@Cu NPs in air at room temperature, which is promising to be used in electronic devices.