甾体甲基化转移酶的研究——有关甾体衍生物的合成

目的 :研究甾体甲基化转移酶。方法 :从γ oryzanol提取的cycloartenol和 2 4(2 8) methylenecycloartenol为初始原料合成目标化合物。结果 :成功地合成了 11个甾体衍生物。结论 :目标化合物均经HPLC纯化 ;结构均经NMR和GC/MS确证 ,方法简便易行。

Kinetics of Sawdust Hydrolysis with Dilute Hydrochloric Acid and Ferrous Chloride

With dilute hydrochloric acid as catalyst and promoted by ferrous chloride, hydrolysis of waste sawdust to produce monosaccharides was conducted by using an one-step method in a batch-wise operation reactor. Based on the model of first order consecutive irreversible reactions, the kinetics equation incorporating the term of catalyst concentration was obtained that is suitable for describing the hydrolysis of sawdust. Activation energies were calculated for hydrolysis of sawdust and decomposition of monosaccharides.

Computational Fluid Dynamic Simulation of Liquid-Liquid Mixing in a Static Double-T-shaped Micromixer

The laminar flow structure and mixing performance of T-shaped and double-T-shaped micromixers with rectangular cross-section have been investigated using computational fluid dynamic (CFD) simulation. FLUENT software is used to evaluate the mixing efficiency. The numerical simulation results show that the presented double-T-micromixer is highly efficient over T-shaped micromixer. The performance of double-T-micromixer with and without static mixing elements (SME) is also investigated. The enhancement in mixing performance is thought to be caused by the generation of eddies and lateral velocity component when the mixture flows through these elements. Mixing efficiency as higher as 97% is reached within a mixing length of 320 μm downstream from the first T-junction with the enhancement of three SMEs.

Experimental and Numerical Investigations of an Ice-slurry Generator

A new test facility equipped with refrigerant and brine circulation systems, and a rotating-scraper ice-slurry generator was constructed to analyze the ice-slurry flow and heat transfer accompanied by phase change in an industrial generator. The axial and transverse brine temperature and ice fraction concentration profiles in the ice generator were measured. The heat transfer efficiency lower than the average was identified in the upper half of the ice generator and its cause was determined by conducting three-dimensional numerical simulation using a commercial CFD code, FLUENT. Approaches of improving the brine-side heat transfer rates were investigated by incorporating extra mixing blades from numerical simulation.

Two-dimensional Simulation for Hydrogen/Air Combustion in a Monolith Reactor

Recent studies on hydrogen combustion were reviewed briefly. The laminar flow and combustion of premixed hydrogen/air mixture in a cylindrical channel of a monolith reactor with and without catalytic wall was numerically modeled by solving two-dimensional (2-D) Navier-Stokes (N-S) equations, energy equation, and species equations. Eight gas species and twenty reversible gas reactions were considered. The control volume technique and the SIMPLE algorithm were used to solve the partial differential equations. The streamlines of the flow field, temperature contours, the entrance length, and the concentration fields were computed. It is found that the entrance zone plays an important role on flow and temperature as well as species distribution. Therefore, the flow cannot be assumed either as fully developed or as plug flow. There is a small but strong thermal expansion zone between the wall and the entrance. Both diffusion and convection affect the heat and mass transfer processes in the expansion zone. Thus the equations of momentum, energy and species conservations should be used to describe hydrogen/air combustion in the monolith reactor. The hot-spot location and concentration field of the homogeneous combustion is strongly influenced by the inlet velocity and temperature, and the equivalence ratio. The catalytic combustion of premixed hydrogen/air mixture over platinum catalyst-coated wall in a cylindrical channel was also simulated.

Coupling System for Food Wastes Anaerobic Digestion and Polyhydroxyalkanoates Production with Ralstonia eutropha

A new technology was developed to couple the anaerobic digestion of food wastes with production of polyhydroxyalkanoates (PHAs). Acetic, propionic, butyric and lactic acids were produced during food wastes anaerobic digestion and their concentrations reached 5.5, 1.8, 27.4 and 32.7 g/L, respectively under appropriate digestion conditions. The fermentative acids were transferred through a dialysis membrane to an air-lift reactor for PHA synthesis by Ralstonia eutropha. Dry cell concentration and PHA content reached 22.7 g/L and 72.6%, respectively. The obtained PHA was a copolymer of b-hydroxybutyrate (HB) and b-hydroxyvalerate (HV) with 2.8% (mole ratio) of HV units in polymer.

Synthesis and characterization of a new water-soluble sodium 5,7,4'-trihydroxyflavone-6,3'-disulfonate

Aim To synthesize a new water-soluble Na 2(C15H8O5)(SO3) 2 and determine its structure.Method The new water-soluble apigenin sulfonated derivative was synthesized by sulfonation with concentrated sulfuric acid at 40℃for half an hour and the products were obtained in ethanol-water(V∶V =1∶1).The structure of the product was identified by IR,NMR spectrum and elemental analysis.Results and Conclusion After highly selective introduced two - SO 3 groups at C3′and C6of the substrate,the new water-soluble apigenin sulfonated derivative,sodium 5,7,4 '-trihydroxyflavone-6,3′-sulfonate was obtained in good yield(78%) at moderate conditions.This method is an ideal synthesis way because of its simple operation,mild reaction conditions,high selectivity,easy separation of the product and higher yield.

Study on the insecticidal activities of the extracts from four plants under orthogonal test

Aim To prepare dry powder insecticide by mixing the plant samples of Aconitum ochranthum Mey.,Aconitum hemsleyanum Pritz.and Dictamnus dasycarpus Turcz.Method The dosage ratios of the break stocks from the plants mentioned above are installed as four factors,and three levels are selected for every factor.The test is actualized according to L 9(3 4) orthogonal array.Results An optimized recipe A 3 B 3 C 3 D 1 has been obtained after considering multifarious factors such as the resources of these plants and the water-solubility of samples.Conclusion The dry powder insecticide prepared by mixing the plant samples mentioned above as 1∶1∶1mass ratio revealed that insecticidal activities for cickets,grasshopper,aphid,and 3rd instar Mythimna separata walker are significant,respectively.

Structure modification of unsaturated natural products:The epoxidation of carbon-carbon double bonds in some natural products with hydrogen peroxide catalyzed by iodine

Aim To afford an environmentally benign catalytic epoxidation of carbon-carbon double bonds in organic substrates using hydrogen peroxide as an oxidant and iodine as a catalyst.Method The effects of different factors on the epoxidation of three unsaturated natural products were investigated by orthogonal design.Results The experimental results show that three unsaturated natural products are oxidized to the corresponding epoxides with hydrogen peroxide in the presence of 10%(mol/mol) of iodine at room temperature in high yields.Conclusion Iodine was found to be an efficient catalyst for the epoxidation of carbon-carbon double bonds in some unsaturated natural products with hydrogen peroxide at room temperature.

Thermodynamic properties of three alkaloids in normal saline

Aim To provide a potent reference for the clinical application of these alkaloids.Method The enthalpy of dissolution for these alkaloids in normal saline are measured using a RD4962000Calvet Microcalorimeter at 36.5℃under atmospheric pressure.Results The differential enthalpy(Δ dif H m) and molar enthalpy(Δ sol H m) were determined for these alkaloids in normal saline.Conclusion On the basis of these experimental data and calculated results,the kinetic equation,half-life,Δ sol H m,Δ sol G m andΔ sol S m of the dissolution process were also obtained.

Several oxygenated monoterpenes from petals of Rosa damascena

Aim To discover the oxygenated monoterpenes that play a critical role in the biosynthetic pathway of monoterpene in Rosa damascene.Method Several kinds of isolation techniques such as liquid-liquid partition,silica column chromatography,thin layer chromatography and high performance liquid chromatography were used to separate the compounds and several identification techniques such as GC-MS and 1H-NMR were used to determine the structure of the isolated compounds.Results Three oxidized acyclic monoterpenes were obtained.They are 8-hydroxygeraniol,8-hydroxynerol and 8-hydroxylinalool.Conclusion The compounds are the important materials of pharmaceutical,cosmetic and food industries.The work has not only provided a new method for the determination of the main aromatic components of Rosa damascena,but also built up an important foundation for the study of biosynthesis of monoterpenoids in the plant.

Synthesis of dihalogenated coumarin derivatives for monitoring acid phosphatase activity

Aim To synthetize 6-chloro-8-fluoro-4-methylumbelliferone phosphate(CF-MUP) and utilize it to analyze acid phosphatase activity.Method CF-MUP obtained by phosphorylation of CFMU(6-chloro-8-fluoro-4-methylumbelliferone) which was prepared by Pechmann reaction between 4 and ethyl acetoacetate in the presence of methanesulfonic acid.And then,the utility of CF-MUP as a substrate for acid phosphatase was compared with MUP(4-methylumbelliferone phosphate).Results The new coumarin phosphate,CF-MUP,demonstrated much higher sensitivity and was more robust for detecting the activity of acid phosphatase than MUP in the physiological pH range.Conclusion This new fluorescence dye,CF-MUP,is a convenient tool for the continuous assay of acid phosphatases with a wide range of pH.

Biological activity of Dictamnus dasycarpus against Mythimna setarata

Aim To gain the active compounds fromDictamnus dasycarpus.Method The solvent partition,preparative TLC,spectral analysis and bioassay are used to gain the active compounds.Results Fraxinellone is a main biological actives substance fromD.dasycarpus was gained.Conclusion Its antifeeding rate and death rate of 72hat 0.21%(mass percent) against Mythimna setarata were 90.4%and 95.2%,respectively.

Immobilized-metal affinity chromatography adsorbent with paramagnetism and its application in purification of the proteins in the natural products

Aim To investigate a new method for synthesis of an Immobilized-Metal Affinity Chromatography(IMAC) adsorbent with superparamagnetism(Fe3O4/SiO2-GPTMS-Asp-Co).Method The magnetic microspheres were synthesized in situ modification and the transmission electron microscope,field emission scanning electron microscopy,X-ray diffractometer,energy spectrometer and vibrating sample magnetometer were used to characterize the appearance,particle size distribution,phase composition,chemical constituents and magnetic properties of silica magnetic microspheres(MMS).Results The silica MMS prepared by reverse microemulsions exhibit a superior core-shell structure.The size distribution of the microspheres varies from between 100 nm to 200 nm and the main phase of microspheres is amorphous SiO2 and spinel Fe3O4.The microspheres retain superparamagnetism and can be used as biomaterials.Conclusion The result indicates that the IMAC adsorbent we prepared has outstanding advantages in the separation of the natural products proteins from the crude bacterial lysate,such as simple operation,high selectivity and capacity.

Traditional Chinese medicine mask for freckles-removal and its preparation

Aim To investigate Traditional Chinese medicine(TMC) mask for freckles-removal because failed facial expression of qi(气) and blood due to their stasis and transport stagnancy is the key factor causing freckles.Method Traditional Chinese medicine is used to remove freckles.TMC mask,which contains Angelica sinensis,Angelica dahurica,Ampelopsis japonica,Bletilla striata,Ligusticum chuanxiongand Asarum sieboldii Miq 100g respectively,is the most respected in facial skin cosmetology in recent years.Results TCM facial mask is used to remove age spots and freckles.They generally help to make the skin smooth and firm and also help in curing freckles gradually.Conclusion The specific active ingredients along with breakthrough of skin absorption barrier are the keys for its effectiveness.

Alkaloidal compounds and bioactivities of three medicinal plants of Menispermaceaefamily in Qinling Montain

Aim To find the original active compounds from three medicinal plants of Menispermaceae family in Qinling Montain,Shaanxi,China.Method Several kinds of isolation techniques such as liquid-liquid partition,column chromatography,thin layer chromatography and sephadex LH-20 gel chromatography are used to separate the compounds and all kinds of identification techniques such as mass,high resolution mass,1H-NMR,13C-NMR,all kinds of 2D-NMR,CD spectra and X-ray diffraction analysis are used to determine the structure of the isolated compounds;several enzymes linked immunosorbent assay are used to test the biological activities of some isolated compounds.Results 30 alkaloids were isolated and identified from Sinomenium acutum of which 8 are new compounds;nine alkaloids were isolated and identified from Menispermum dauricum of which 6 are new compounds;six alkaloids were isolated and identified from Stephania epigaea.Among all the identified alkaloids,six compounds show protective effects against hydrogen peroxide induced cell injury;eight compounds show weak or strong cytotoxicity activity;one compound shows neuroprotective effect against hydrogen peroxide and.β-amyloid25-35-induced oxidative injury.Conclusion These three plants of Menispermaceae family may be considered as the potential drugs for Alzheimer's disease therapy and anticancer agents.

Dynamic Force Reduction and Heat Transfer Improvement for Horizontal Tubes in Large-Particle Gas-Fluidized Beds

The effects of tube bank configuration on forces and heat transfer were investigated for both two-dimensional and three-dimensional gas fluidized beds. Effective dynamic forces and heat transfer coefficients were measured for several tube bank configurations, and it was found that the average forces are smaller than for a single tube. The heat transfer coefficient can be increased by providing sufficient space for particles to descend around both sides of the tube bank. The results provide useful guidelines for optimizing the configuration of tube banks to achieve high heat transfer coefficients while reducing tube erosion due to dynamic forces.

Effects of Supports and Promoter Ag on Pd Catalysts for Selective Hydrogenation of Acetylene

SiO2,α-Al2O3,γ-Al2O3,ZrO2 and CeO2 were used as supports and Ag as promoter to study their effects on Pd catalysts for selective hydrogenation of acetylene.The catalysts were prepared by impregnated synthesis and characterized by XRD,BET and TEM.The catalytic reaction was carried out in a fixed-bed reactor.Overall,the low specific surface area supports were better to increase the ethylene selectivity at high conversion rate of acetylene.Among the four Pd catalysts on low specific surface area supports,the catalyst on low specific surface area SiO2(LSA-SiO2) retained a high ethylene selectivity even at complete conversion,while the other catalysts showed significant decrease in the selectivity at complete conversion.The performance of Pd/LSA-SiO2 was important to decrease the loss of ethylene in selective hydrogenation of trace acetylene in ethylene.Addition of Ag to Pd/LSA-SiO2 significantly decreased the formation of ethane,C4 alkenes and green oil,and improved the ethylene selectivity to 90% when Pd:Ag=1:1 and 1:3(ω).When the ratio of Pd to Ag was above 1,the activity of Pd-Ag bimetallic catalyst was similar to that of Pd monometallic catalyst,and the selectivity of ethylene increased with increasing of amount of Ag.When the ratio of Pd to Ag was below 1,the activity of bimetallic catalyst decreased with increasing of amount of Ag,while the selectivity of ethylene was kept unchanged.The optimum temperature was 200-230℃ for 0.02%(ω)Pd-0.02%(ω)Ag/LSA-SiO2 to give a high ethylene selectivity and low formation of green oil.

Preparation of Sn-Si-C Composite as Li-ion Battery Anode Material by High Energy Ball Milling and Its Properties

Electrochemically active Sn-Si-C composite was synthesized by high energy ball milling(HEBM) in Ar atmosphere.The so-obtained composite was characterized by X-ray diffraction and field emission scanning electron microscopy.Lithium insertion/extraction characteristics of the composites were examined by constant current charge-discharge and cyclic voltammetry methods.The results show that there is no new alloy generated by HEBM.The composite synthesized by two-step HEBM resulted in initial lithium insertion specific capacity as high as 1224 mA×h/g and higher reversible lithium extraction specific capacity of 855 mA×h/g.