维甲酸对实验性大肠癌的逆转治疗作用

目的;观察维甲酸(RA)对实验性大肠癌的逆转治疗作用。方法:应用维甲酸对大鼠大肠癌的诱发过程进行干预治疗,观察癌变率及增殖细胞核抗原(PCNA)和核仁组成区嗜银蛋白(AgNOR)的表达。结果:维甲酸治疗组(Ⅱ组)大肠癌的发生率显著低于未加维甲酸治疗的对照组(Ⅰ组)。在诱癌的中晚期PCNA指数及AgNOR数亦显著低于Ⅰ组(P<0.01)。Ⅰ、Ⅱ组的PCNA指数及AgNOR数显著高于未用诱癌剂的Ⅲ、Ⅳ组(P<0.01)。组内对比结果显示,Ⅰ组PCNA指数及AgNOR数有随着诱癌时间延长而增加的趋势,差异有显著性(P<0.05),而Ⅱ、Ⅲ、Ⅳ组内比较差异无显著性(P>0.05)。结论:维甲酸可完全或部分阻逆实验性大肠癌的癌变过程,降低其发生率,为临床应用维甲酸防治大肠癌提供了理论资料。

环维黄杨星D-甲醇结晶体对大鼠心室肌细胞内向整流钾电流的影响

目的:观察环维黄杨星D(Cyclovirobuxine D,CVB-D)-甲醇结晶体溶液对大鼠单个心室肌细胞内向整流钾电流(in-ward rectifier current,IK1)的影响。方法:Langendorff灌流系统灌流大鼠离体心脏,急性酶解法获得单个心室肌细胞;全细胞膜片钳技术分别记录对照组、药物组及洗脱组的IK1曲线。结果:对于大鼠心肌细胞,在钳制电位-100 mV时,给予低浓度(4×10-4g/L)、高浓度(4×10-3g/L)CVB-D-甲醇结晶体溶液后,IK1内向电流峰值和内向电流稳态值与给药前相比均明显降低,IK1外向电流峰值也明显受到抑制。使用细胞外液灌流洗脱药液后,与给药后相比IK1内向电流峰值和内向电流稳态值均升高,IK1外向电流峰值升高显著。结论:4×10-4g/L组和4×10-3g/L组CVB-D-甲醇结晶体溶液对IK1内向电流成分和外向电流成分均具有可逆性抑制效应,这可能是其具有延长动作电位时间与抗心律失常作用的药理机制之一。

Effective production of γ-valerolactone from biomass-derived methyl levulinate over CuO_x-CaCO_3 catalyst

The production of?-valerolactone(GVL)from lignocellulosic biomass has become a focus of research owing to its potential applications in fuels and chemicals.In this study,(n)CuOx-CaCO3(where n is the molar ratio of Cu to Ca)compounds were prepared for the first time and shown to function as efficient bifunctional catalysts for the conversion of biomass-derived methyl levulinate(ML)into GVL,using methanol as the in-situ hydrogen source.Among the catalysts with varied Cu/Ca molar ratios,(3/2)CuOx-CaCO3 provided the highest GVL yield of 95.6% from ML.The incorporation of CaCO3 with CuO resulted in the formation of Cu+species in a CuOx-CaCO3 catalyst,which greatly facilitated the hydrogenation of ML.Notably,CuOx-CaCO3 also displayed excellent catalytic performance in the methanolysis products of cellulose,even in the presence of humins.Therefore,a facile two-step strategy for the production of GVL from cellulose could be developed over this robust and inexpensive catalyst,through the integration of cellulose methanolysis catalyzed by sulfuric acid,methanol reforming,and ML hydrogenation in methanol medium.

Methanol Synthesis from CO2 Hydrogenation with a Cu/Zn/Al/Zr Fibrous Catalyst

A highly active Cu/Zn/Al/Zr fibrous catalyst was developed for methanol synthesis from CO2 hydrogenation. Various factors that affect the activity of the catalyst, including the reaction temperature, pressure and space velocity, were investigated. The kinetic parameters in Graaf＇s kinetic model for methanol synthesis were obtalned. A quasi-stable economical process for CO2 hydrogenation through CO circulation was simulated and higher methanol yield was obtained.

Catalytic performance of hybrid Pt@ZnO NRs on carbon fibers for methanol electro-oxidation

A novel Pt@ZnO nanorod/carbon fiber （NR/CF） with hierarchical structure was prepared by atomic layer deposition combined with hydrothermal synthesis and magnetron sputtering （MS）. The morphology of Pt changes from nanoparticle to nanorod bundle with controlled thickness of Pt between 10 and 50 nm. Significantly, with the increase of voltage from 0 to 0.6 V （vs. standard calomel electrode）, the prompt photocurrent generated on ZnO NR/CF increases from 0235 to 0.725 mA. Besides, the Pt@ZnO NR/CF exhibited higher electrochemical active surface area （ECSA） value, better methanol oxidation ability and CO tolerance than Pt@CF, which demonstrated the importance of the multifunctional ZnO support. As the thickness of Pt increasing from 10 to 50 rim, the ECSA values were improved proportionally, leading to the improvement of methanol oxidation ability. More importantly, UV radiation increased the density of peak current of Pt@ZnO NR/CF towards methanol oxidation by additional 42.4%, which may be due to the synergy catalysis of UV light and electricity.

Isolation and Identification of Nicotiflorin and Narcissin from the Aerial Parts of Peucedanum aucheri Boiss.

Peucedanum aucheri Boiss. （Apiaceae） is a herbaceous wild plant native to Iran and is used in Iranian folk medicine as a diuretic and for the treatment of kidney disorders. Phytochemical investigation of different extracts prepared from the aerial part of P. aucheri Boiss. resulted to the isolation of two main flavonol glycosides from methanolic extract. Using comprehensive spectroscopic methods, including 1D and 2D nuclear magnetic resonance （NMR） spectroscopy and mass spectroscopy, chemical structure of isolated compounds were determined as kaempfrol-3-o-rutinoside （nicotiflorin） and isorhamnetin-3-o-rutinoside （narcissin）. Although narcissin has previously been isolated from P. ruthenicum, to the best of our knowledge, isolation of nicotiflorin from Peucedanum genus is reported for the first time.

Properties of Surface Cyclic Oligomers Present on Polyester Fiber

The effects of different treatments, such as dry heat,wet heat, solvent vapor and ultrasonic, on propertiesof the cyclic oligomers on the surface of polyester fiberare studied. The components of surface oligomers areanalyzed through Thin-Layer Chromatograph. Theresult shows that: all of the treatment, especially solvent vapor treatment,call significantly increase the content of surface cyclic oligomers.The content of cyclic triIner is increased more considerably than other oligomers. Moreover,the morphology and thedistribution of surface cyclic oligomers are also different from different treatments:Dry heat and wet heat cause larger polygonal solids distributed evenly on the surface of fiber;solvent vapor nlakes fiber surface exhibit irregular rodlike crystal shapes randomly;ultrasonic treatment induces some obscureand smaller deposi^on the surface of fiber.

Study on methanol synthesis from coal-based syngas

The intrinsic kinetic models of the Langmuir-Hinshelwood type were investigated in terms of the reaction rates of CO hydrogenation and CO_2 hydrogenation in theform of reactant fugacity. The parameters were estimated by the Universal Global Optimization using the Marquardt method. Residual error distribution and statistic tests show thatthe intrinsic kinetic models are reliable and acceptable. The mathematic model of a combined converter formed by gas-cooled and water-cooled reactor was developed and thegas-cooled reactor and the water-cooled reactor were characterized with one-dimensionalmathematic model. The distributions of temperature and concentration in the catalytic bedof the gas-cooled reactor and the water-cooled reactor in a combined converter with ayield of 1.2 Mt/a were simulated. The parallel cross linking pore model was used to describe the transfer process of multi-component diffusion system in the catalyst. The calculated value computed by the internal diffusion efficiency factor calculation model established for methanol synthesis catalyst fit the experimental value very well.

Biocompatibility Evaluation of Polyethylene Terephthalate Artificial Ligament Coating Hydroxyapatite by Fibroblasts Cells in Vitro

Hydroxyapatite(HA) based materials have been widely used in the field of ligament tissue engineering in the past decades.It has been previously reported that HA can increase the penetration of marrow-derived mesenchymal stem cells(MSCs) and MSCs cells into scaffolds due to increased cell differentiation in biological media.Additionally,it was found that there are much difference between MSCs and anterior cruciate ligament (ACL) cells.For that reason,we mainly evaluate the biocompatibility of polyethylene terephthalate(PET) silk scaffold with fibroblasts cells in vitro.We cultured mouse fibroblasts cells on the substrate of PET fiber and PET-HA scaffold,respectively,and then observed the morphology by using scanning electron microscopy.Our data indicate that PET-HA scaffold has good biocompatibility with fibroblasts cells and can potentially be useful in enhancing the fibroblasts cell differentiation and proliferation.