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In this study, the interactions of six different flavonoids (IVa~c and Va~c) with bovine serum proteins (BSA) were investigated by fluorescence spectroscopy, thermodynamic and molecular dynamics simulations. The fluorescence behaviors of IVa~c and Va~c were quantitatively related to BSA, and the results calculated using the Stern-Volmer equation showed that IVa~c and Va~c had significant fluores-cence quenching with BSA, both of which were static quenching. The binding ability of monofluoroflavone with BSA was best when its fluorine atom was at para position, while the binding ability of monofluoroflavonol with BSA was best when its fluorine atom was at meta position. The binding ability of monofluoroflavonol with BSA was stronger than that of monofluoroflavone when hydroxyl group was attached to the C(3) of monofluoroflavone IVa~c. The calculated thermodynamic parameters of IVa~c and Va~Va were ΔG<0, ΔH<0 and ΔS<0, indicating that the interaction of IVa~c and Va~Vc with BSA was a spontaneous exothermic process, which mainly relies on hydrogen bonding and van der Waals force. [ABSTRACT FROM AUTHOR]

Abstract: A concept of methane yield at optimum pH was advanced and subsequently a mathematical model that simulates the optimal pH of a batch process for anaerobic digestion of organic fraction of municipal solid waste (MSW) was developed and validated. The model was developed on the basis of the microbial growth kinetics and was divided into three processes: hydrolysis of substrates by hydrolytic bacteria, consumption of soluble substrate by acidogenic bacteria, and finally consumption of acetate and methane generated by methanogenic bacteria. Material balance and liquid phase equilibrium chemistry were used in this study. A series of experiments were conducted to validate the model. The model simulation results agreed reasonably with experimental data in different temperatures and total solid (TS) concentrations under uncontrolled pH. A computer circulation program was used to predict the optimal pH in different conditions. Experiments in different temperatures and TS were run under optimal pH which predicted by the model. The model was succeeded in increasing the methane production and the cumulative methane production had an average increment about 35% in optimal pH of different temperatures and TS. [Copyright &y& Elsevier]

ABSTRACT: In this paper, mathematical models of smooth and enhanced tubes were established. A new mathematical model in evaluating single-tube falling film absorption effect outside enhanced tubes is proposed. The liquid film outside enhanced tubes is assumed to consist of two layers, i.e. internal and external layers. The analytical solutions to the distribution of the velocity, temperature and concentration in the internal layer are obtained by means of theoretical analysis, while the solutions in the external layer are calculated by using numerical method. The governing equations of the two layers are coupled using a second-order coupling method. The effects of the height and the angle of the ribs on the performances of the heat and mass transfer of the liquid film are discussed. It is shown that the agreement is good between the calculation results and the experimental data. [Copyright &y& Elsevier]

Objective: To extract and isolate the biologic-active components of the oil-soluble components obtained from the fruit of Evodia rutaecarpa., Methods: Various chromatographic techniques were used to isolate and purifie the biologic-active components, the IR and NMR spectra were used to identify the structure of this compound from Evodia rutaecarpa, and the content and the chemical structure was calibrated with a standard mixture was by TLC., Results: A crystal compound was isolated from the Evodia rutaecarpa of Rutaceae, and was elucidated as oleanolic acid., Conclusion: The main chemical constituents of oil-soluble components obtained from the fruit of Evodia rutaecarpa are terpenoid compounds, the content of oleanolic acid is 1.8%.

Using a material and ionization balance analysis of anaerobic digestion process, a kinetic model of pH control in a batch anaerobic digestion of organic fraction of municipal solid waste was established on the basis of substrate decay and microbial growth kinetics, and a corresponding computer soft ware was created. The optimal pH in different anaerobic digestion can be predicted by this model. Consequently the maximal methane production can be obtained in anaerobic system by controlling the pH in optimal value. Comparative experiments were conducted to validate the model. The experiments demonstrated that the methane production of anaerobic system under optimal pH was steadier than the same condition under uncontrolled pH, and the cumulative methane production had an average increment about 20%.