摘要：
A quantitative structure-spectrum relationship (QSSR) model was developed to simulate 13C nuclear magnetic resonance (NMR) spectra of carbinol carbon atoms for 55 alcohols. The proposed model, using multiple linear regression, contained four descriptors solely extracted from the molecular structure of compounds. The statistical results of the final model show that R 2=0.982 4 and S=0.869 8 (where R is the correlation coefficient and S is the standard deviation). To test its predictive ability, the model was further used to predict the 13C NMR spectra of the carbinol carbon atoms of other nine compounds which were not included in the developed model. The average relative errors are 0.94% and 1.70%, respectively, for the training set and the predictive set. The model is statistically significant and shows good stability for data variation as tested by the leave-one-out (LOO) cross-validation. The comparison with other approaches also reveals good performance of this method. Key wordscarbinol carbon atom– 13C nuclear magnetic resonance–chemical shift–topological indices–quantitative structure-spectroscopy relationship
关键词：
DEAMIDATION;GLUTAMINASES;GLUTELINS;HYDROLASES;MODIFICATION;PH;PROTEINS CEREAL;RICE;SOLUBILITY;STRUCTURE;Catering;speciality and multi-component foods;Protein isolates
摘要：
The effects of glutaminase on deamidation of rice glutelin were investigated. Water-insoluble rice glutelin was deamidated to the extent of deamidation degree 52.29% in 200 mmol/L sodium phosphate buffer (pH 7.0) at 37 degrees C for 48 h. Zeta potential analysis indicated that the glutamines of rice glutelin were deamidated into glutamic residues. Size exclusion chromatography results demonstrated that glutaminase deamidation broke the hydrophobic, hydrogen and some intermolecular disulfide bonds in rice glutelin and thereby rearranged the molecular weight distributions without serious cleavage of the peptide bonds. Fourier transform infrared analysis revealed the transformation of alpha-helix to random coil and beta-turn by deamidation and suggested that deamidated rice glutelin maintained more flexible or extended forms. Solubility properties of rice glutelin in mildly acid (pH 5) and neutral buffers (pH 7) were remarkably improved by glutaminase deamidation. These new features of deamidated rice glutelin suggested that glutaminase could be a potential tool for enhancing the usability of rice protein in the food industry. (C) 2011 Elsevier Ltd. All rights reserved.
摘要：
The frequency domain power spectra of acoustic emission (AE) signals from different metal-acid reaction processes such as 6111 Al-alloy-hydrochloric acid (HCl) and 7070 Al-alloy-HCl for evolving hydrogen gases were obtained by fast Fourier transform (FFT) program and used for chemical analysis of different metal materials. Averaged power spectra from these processes and their corresponding characteristics were extracted. The characteristic AE frequency signals could be used for chemical pattern recognition of different metal materials like 6111 and 7050 aluminum alloys from the metal-acid reaction processes, that the principal component analysis (PCA) with appropriate frequency selection procedure gave a satisfactory classification with a correct rate of 78.1%. The back-propagation (BP) algorithm of artificial neural network (ANN) could give better recognition of AE signals for 6111 and 7050 alloys with a correct rate of 100%. Moreover, the AE energetic parameters are linearly correlated with the pH value of the acidic buffer solution, which opens a new possibility for quantitatively analytical application of AE signals on metal materials.
作者机构：
[黄可龙; 戴益民] School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;[Zeng, Ju-Lan; 李浔; 曹忠; 戴益民] School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410004, China;[Zeng, Ju-Lan; 李浔; 曹忠; 戴益民] Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, Changsha University of Science and Technology, Changsha 410004, China
通讯机构：
School of Chemistry and Chemical Engineering, Central South University, China
关键词：
Acid-deamidation;Microstructure;Rheology;Rice protein
摘要：
Microstructure and theological properties of mixtures of acid-deamidated rice protein (ADRP) and dextran were studied. The microstructures of the ADRP/dextran mixtures were described using confocal laser scanning microscopy (CLSM), which revealed the effective association among ADRP and formation of a protein network-like structure in the mixture with higher protein concentration. Mechanical properties of the mixtures were observed by rheometer. The steady shear measurements showed a correlation with the CLSM results via a marked increase in the viscosity of the mixtures with protein association. Frequency sweeps further evidenced the build-up of the gelled network-like structure. The differences in fracture forces observed by textural measurements between mixture and single ADRP gel also suggested the difference in microstructures. The formation of network-like structure appeared to have occurred through a phase separation of ADRP and dextran. (c) 2009 Elsevier Ltd. All rights reserved.
摘要：
A series of Cu-ZnO-Al2O3 catalysts with various metal compositions of Cu/Zn/Al were prepared by the co-precipitation method, and screened for glycerol hydrogenolysis to propylene glycol. The catalyst with a Cu/Zn/Al molar ratio of 1:U1:U0.5 exhibited the best performance for glycerol hydrogenolysis, and thus selected for kinetic investigation. Under elimination of external and internal diffusion limitation, kinetic experiments were performed in an isothermal fixed-bed reactor at a hydrogen pressure range of 3.0-5.0 MPa and a temperature range of 493-513 K. Based on a dehydration-hydrogenation two-step hydrogenolysis mechanism, a two-site Langmuir-Hinshelwood kinetic model taking into account competitive adsorption of glycerol, acetol and propylene glycol was proposed and successfully fitted to the experimental data. The average relative errors between observed and predicted outlet concentrations of glycerol and propylene glycol were 6.3% and 7.6%, respectively. The kinetic and adsorption parameters were estimated by using the fourth-order Runge-Kutta method together with the Rosenbrock algorithm. The activation energies for dehydration and hydrogenation reactions were 86.56 and 57.80 kJ·mol-1, respectively.
摘要：
Article Crystal structure of 3′′′-(2,6-dichlorophenyl)-1′-methyl-4′,4′′′-bis(4- chlorophenyl)-4′′′,5′′′-dihydroindole-3-spiro-2′-pyrrolidine-3′-spiro-1′- cyclopentane-3″-spiro-5′′′-[1,2]oxazole-2(3H),2″-dione hemihydrate, C36H27Cl4N3O3 · 0.5H2O was published on March 1, 2010 in the journal Zeitschrift für Kristallographie - New Crystal Structures (volume 225, issue 1).
摘要：
Nucleation effects of a novel nucleating agent, bicyclic [2,2,1] heptane di-carboxylate (commercial product name: HPN-68), in isotactic polypropylene (iPP) were studied by using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). The results showed that HPN-68 is a typical nucleating agent for α-iPP and has high nucleation efficiency. Crystallization peak temperature and mechanical properties of iPP nucleated with HPN-68 can be greatly increased with only a low concentration of HPN-68. However, increased concentration of HPN-68 has a saturation value and properties of iPP, which tend to plateau when the concentration of HPN-68 exceeds the saturation value. When the concentration of HPN-68 was 0.2 wt%, the crystallization peak temperature was increased by about 15°C, and the tensile strength and flexural modulus of iPP were increased by 13% and 18%, respectively.
摘要：
Bicyclic [2,2,1] heptane di-carboxylate (commercial product name: HPN-68) is a novel nucleating agent with high nucleation efficiency for isotactic polypropylene (iPP). In this paper, the non-isothermal crystallization kinetics of virgin iPP and iPP nucleated with HPN-68 were investigated by means of a differential scanning calorimeter (DSC).The Caze method was used to analyze the non-isothermal crystallization kinetics. The results show that addition of HPN-68 can increase the crystallization peak temperature (Tp) of iPP greatly under the same cooling rate. Under non-isothermal conditions, the addition of HPN-68 changes the spherulite growth pattern of iPP. For virgin iPP, the growth pattern is mainly spontaneous nucleation followed by three-dimensional spherulite growth, while for iPP nucleated with HPN-68, the growth pattern is mainly heterogeneous nucleation followed by three-dimensional spherulite growth.
摘要：
Non-isothermal crystallization kinetics of isotactic polypropylene (iPP) nucleated with 1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (DMDBS) was studied by using differential scanning calorimetry (DSC). The modified Avrami theory of Jeziorny and the Mo method were used to analyze the DSC data. The results suggested that the two methods were both suitable for crystallization kinetics of iPP nucleated with DMDBS. Half time of the crystallisation (t (1/2)) of virgin iPP was larger than that of nucleated iPP under the same cooling rate. Meanwhile, the required cooling rate of virgin iPP was higher than that of iPP nucleated with DMDBS in order to reach the same relative crystallinity, both of which showed that the addition of nucleating agent DMDBS could increase the crystallization rate of iPP. In addition, incorporation of DMDBS changed the manner of nucleation and development.
