混合溶剂降低蛋白质醇变性机理的探讨

对醇洗法制备花生浓缩蛋白时，乙醇浓度与产品溶解性的关系进行了研究。采用混合溶剂制备花生浓缩蛋白，可获得蛋白质变性程度低、溶解性好的产品。

不同处理方法对醇变性大豆蛋白溶解特征影响的研究

通过不同的处理方法对醇变性大豆蛋白(ASP)进行改性。分别考察了高速剪切处理、加热处理、酸处理和碱处理对醇变性大豆蛋白溶解特征的影响。实验结果表明,高速剪切处理能提高醇变性大豆蛋白的溶解性;高速剪切和加热处理过的醇变性大豆蛋白溶解时,随着温度的升高溶出的聚集体会增多,而酸和碱处理后的情况则相反。

高静压处理对醇变性大豆11S球蛋白影响研究

研究了高静压处理对醇变性大豆11S球蛋白溶解性及结构性质的影响。结果表明,大豆11S球蛋白以1:15的比例添加65%乙醇处理后溶解度降低为14.24%。利用300 MPa高静压处理醇变性大豆11S球蛋白,可使其溶解度恢复至95.5%。凝胶渗透色谱显示,醇变性大豆11S球蛋白在不同高静压下形成多种相对分子质量的可溶性聚集体。荧光光谱和圆二色谱对高静压处理的醇变性大豆11S球蛋白结构的测定证实其结构逐步被打开,形成柔性三级结构;醇诱导稳定的α-螺旋结构部分被破坏,高静压处理后蛋白的二级结构以β-折叠为主。

醇变性大豆7S球蛋白结构特征研究

利用不同体积分数乙醇溶液对大豆7S球蛋白进行变性。分别对醇变性大豆7S球蛋白溶解度、表面疏水性、二级结构和聚集形态进行分析。大豆7S球蛋白经醇溶液变性后，溶解度在乙醇体积分数为55％～65％时基本达到最低值；表面疏水性在乙醇体积分数为25％和65％时分别达到最大值和最小值。傅立叶红外光谱表明，在乙醇体积分数较低时，β-折叠结构能稳定存在；在乙醇体积分数较高时，β-折叠和α-螺旋之间结构发生转变，呈现较高螺旋态。凝胶电泳表明，7S球蛋白亚基间以非共价相互作用力为主；经醇变性后，导致聚集体产生，且7S球蛋白分子间非共价相互作用随乙醇体积分数增大呈有逐渐增大趋势。

影响低温棉籽蛋白KOH蛋白质溶解度因素的研究

使用有机溶剂将棉仁中的棉籽油和棉酚萃取后,余下的棉籽蛋白是一种优良的动物饲料原料。棉籽蛋白KOH蛋白质溶解度的高低直接影响动物对饲料中蛋白质的吸收率。结合生产实际研究了醇、热等变性因素在加工过程中对低温棉籽蛋白KOH蛋白质溶解度的影响,确定了最佳工艺参数,优化了低温棉籽蛋白加工工艺。

Design and control of methyl acetate-methanol separation via heat-integrated pressure-swing distillation

Design and control of pressure-swing distillation(PSD) with different heat integration modes for the separation of methyl acetate/methanol azeotrope are explored using Aspen Plus and Aspen Dynamics. First, an optimum steady-state separation configuration conditions are obtained via taking the total annual cost(TAC) or total reboiler heat duty as the objective functions. The results show that about 27.68% and 25.40% saving in TAC can be achieved by the PSD with full and partial heat integration compared to PSD without heat integration. Second,temperature control tray locations are obtained according to the sensitivity criterion and singular value decomposition(SVD) analysis and the single-end control structure is effective based on the feed composition sensitivity analysis. Finally, the comparison of dynamic controllability is made among various control structures for PSD with partial and full heat integration. It is shown that both control structures of composition/temperature cascade and pressure-compensated temperature have a good dynamic response performance for PSD with heat integration facing feed flowrate and composition disturbances. However, PSD with full heat integration performs the poor controllability despite of a little bit of economy.

Electrochemical synthesis, characterization and thermal properties of niobium ethoxide

Niobium(V) ethoxide(Nb(OEt)5) was synthesized by electrochemical reaction of ethanol with niobium plate as the sacrificial anode,stainless steel as the cathode and tetraethylammonium chloride(TEAC) as the conductive additive.The condensates were isolated by vacuum distillation under 5 kPa.The product was characterized by Fourier transform infrared(FT-IR) spectra,Raman spectra and nuclear magnetic resonance(NMR) spectra.The results indicate that the product is niobium ethoxide.Thermal properties of niobium ethoxide were analysed by TG/DTG.Vapour pressure was calculated from the Langmuir equation and the enthalpy of vaporization was calculated from the vapour pressure-temperature data using the Clausius-Clapeyron equation.The concentrations of impurity metallic elements in the sample were detected by ICP-MS.It is shown that the purity can reach 99.997%.The volatility and purity of the niobium ethoxide ensure that it could be a good precursor for chemical vapor deposition and atomic layer deposition of niobium oxide layers.

A Structure-properties Study of MDI-based Hydrophilic Polyether-polyester Polyurethane

A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and polyethylene glycol 1000 (PEG1000), with 1,4-butanediol (BDO) as the chain extender. Furthermore, several representative properties of the polyurethanes, such as moisture permeability, water resistance, hydrophilic property, and phase inversion temperature, were investigated. The studies show that the structure and concentration of soft segment have a remarkable effect on the main application properties of polyurethane. On the contrary, the functional properties of the polyurethane are almost not affected by its hard segment.

Experimental study on freezing of liquids under static magnetic field

Freezing processes of several liquids under static magnetic field(SMF) less than 50 mT were investigated. Central temperature of liquid samples held in glass test tubes immersed in a liquid bath was measured and collected. Nucleation temperature and phase transition time were obtained from freezing curves. Normality tests were performed for nucleation temperature of these liquids with/without magnetic field and normality distributions were justified. Analysis of variances was carried out for nucleation temperature of these liquids with magnetic field flux density as the influencing factor. Results showed that no significant difference was found for deionized water with or without SMF. However, differences exist in 0.9% NaCl solution and 5% ethylene glycol solution with and without SMF. Nucleation temperature of 0.9% NaCl with SMF is lower than that without SMF, while its phase transition time is shorter than that without SMF. Nucleation temperature of 5% ethylene glycol with SMF is higher than that without SMF, while its phase transition time is not modified with SMF.

Rheological properties of polyvinyl butyral/Pluronic F127/PEG200 blend systems

The influence of temperature and mass fraction of Pluonic F127 on the rheological properties of polyvinyl butyric （PVB）/Pluronic F127/polyethylene glycol （PEG） 200 blend systems was investigated by a rotational rheometer with parallel plates. The results show that the blend systems approach homogeneous state at 140, 150 and 160℃while the rheological properties of the blend systems significantly deviate from the homogeneous systems at 120℃. Shear thinning behavior is observed for all the blend systems at different temperatures and is enhanced by increasing Pluronic F127 content. The complex viscosity, storage modulus, loss modulus, zero-shear activation energy and flow recovery of the blend systems increase with the increase of Pluronic F127 content. There is a crossing point for the loss modulus and the storage modulus of each sample at high frequency, which is called specified frequency （SF）. The loss modulus is larger than the storage modulus when the frequency is less than the SF, and when frequency is more than SF, the loss modulus is smaller than the storage modulus.

Effect of Therapeutic Ginger on Genotoxic of Taxol Drug （Anti-Cancer） in Bone Marrow Cell of Male Mice

Medicinal use of spices/herbs has been gradually increased in the developed countries, Zingiber officinale （Ginger） is known to possess potent antioxidant and anti inflammatory properties. Therefore, the aim of this study is to determine the possible anti-mutagenic effect of ginger against the genotoxic effect of anti-cancer drug Taxol 0.6 mg/kg. This study is conducted by using two types of cytogenetic studies in bone marrow cell of mal albino mice Mus musculus （average weight 25-30 g）. The animals were randomly distributed into six groups, each of 14 mi[ce, （GI） was given the solvent, （G2） treatment of the medical dose of Taxol drug, （G3） treatment of ginger, （G4） a pre-treatment of ginger prior to treatment of drug, （G5） a simultaneous treatment of ginger and treatment of drug, （G6） a post-treatment of ginger after treatment drug. The study results show that significant increase in total chromosomal aberrations and significant increase in the number of micronuclei were observed after treatment drug. The significant structural aberrations were in the form of end-to-end associations. The numerical chromosomal aberrations were endomitosis and polyploid. The results showed that the frequencies of chromosomal aberrations and micronuclei in ginger treated group were not significantly different from control. Simultaneous treatment of ginger was found to be effective in reducing the genotoxic effects induced by drug Taxol especially in the total number of the chromosomal aberrations and the number of micronuclei.

Effect of Polyethylene Glycol on the Properties of γ-Al_2O_3 Formation by Polyaluminum Chloride

A polyaluminium chloride solution with high Al 13 content self-prepared was used as material for preparing the spherical γ-Al 2 O 3 by the sol-gel and oil-drop method. Polyethylene glycol with different molecular mass was used as surfactant to investigate the effect on property of γ-Al 2 O 3 . The physical property was characterized by 27 Al NMR (nuclear magnetic resonance) spectra, X-ray diffraction, FT-IR (Fourier transform infrared spectroscopy) and TG-DTA (thermogravimetric-differential thermal analysis). The results showed that surface area, pore volume and pore size of γ-Al 2 O 3 all increased with the increase of polyethylene glycol molecular mass in the experimental research range, and polyethylene glycol 10000 was the most suitable pore forming additive. γ-Al 2 O 3 with surface area of 339 m 2 ·g 1 , pore volume of 0.59 cm 3 ·g 1 and pore diameter of 6.9 nm were obtained at 450 °C.

A review on research progress of transketolase

Transketolase （TK）, a thiamine diphosphate （ThDP）-dependent enzyme, catalyzes several key reactions of nonoxidative branch of pentose phosphate pathway. TK is a homodimer with two active sites that locate at the interface between the contacting monomers. Both ThDP and bivalent cations are strictly needed for TK activation, just like that for all ThDPdependent enzymes. TK exists in all organisms that have been investigated. Up to now, one TK gene （TKT） and two transketolase-like genes （TKTL1 and TKTL2） have been identified in human genome. TKTL1 is reported to play a pivotal role in carcinogenesis and may have important implications in the nutrition and future treatment of patients with cancer. Research- ers have found TK variants and reduced activities of TK enzyme in patients with neurodegenerative diseases, diabetes, and cancer. Recent studies indicated TK as a novel role in the prevention and therapy of these diseases.

Molecular catalysis for the steam reforming of ethanol

In this paper, the application of molecular catalysis for steam reforming of ethanol （SRE） is reviewed. Eight metals （Ni, Co, Cu Pt, Rh, Pd, Ir and Ru） have shown high catalytic activity for SRE. Among them Ni and Rh are very promising because of high d character in the metal bond and low metal-oxygen bonding （vs. metal-carbon）. They can effectively promote C-C bond cleavage in the rate-determining process during SRE. However, Rh is weak in water-gas-shift so that CH4 and CO become the main by-products at low reaction temperatures, while Ni catalysts suffer from rapid deactivation due to coking and sintering. Two low-temperature CO-free catalysts have been developed in our lab, namely Rh-Fe/Ca-Al2O3 and carbonyl-derived Rh-Co/CeO2, in which the presence of iron oxide or Co can promote water-gas-shift reaction and significantly improve the SRE performance. On the other hand, adding 3 wt% CaO to Ni/Al2O3 can greatly improve the catalyst stability because the Ca modification not only increases Ni concentration on the Ni/Ca-Al2O3 surface and 3d valence electron density, but also facilitates the water adsorption and coke gasification via water-gas-shift. The availability of abundant surface OH groups helps the formation and conversion of adsorbed formate intermediate. Hence, ethanol reaction on Ca-Al2O3-supported Ni, Pt, Pd and Rh catalysts are found to follow the formate-intermediated pathway, a new reaction pathway alternative to the traditional acetate-interrnediated pathway.