Advanced Materials Research Vols. 236-238

Abstract: Curcumin, a hydrophobic polyphenol derived from rhizome (turmeric) of the herb Curcuma longa, have been shown to exhibit antioxidant, anticarcinogenic anti-inflammatory, antimicrobial and nephroprotective activities, et al. Among these, its potent antioxidant activity is worthwhile of special attention, because oxidative stress is involved in the pathogenesis of cancer, neurodegenerative diseases, et al. This review focuses on the ways that curcumin exerts its antioxidant activity, including direct chemical reaction with free radicals, chelation with metals ions which results in oxidative stress, regulation of antioxidant-related enzyme activity and gene expression. Meanwhile the disputed chemical antioxidant mechanism is also discussed.

Abstract: A novel one-component polyurethane was synthesized by 2,4,6-trichlorophenol (TCP) as blocking agent for polymethylene polyphenyl isocyanate (PAPI). FTIR spectrum indicates that the NCO groups of the isocyanate molecule are blocked with TCP and the added catalyst should make the reaction faster than that of un-added catalyst. The one-component was characterized by ¹H NMR and ¹³C NMR.

Abstract: In this paper, the tests of the thermo-mechanical fatigue of the material, cut from a coke tower were performed. The tower made of 20G has been in service for 20 years. Then, we calculated the temperature and stress-strain. The results showed that the tower can be in service for another four years．

Abstract: The aim of this work was to optimize the process parameters through the statistical approach for the production of alpha amylase by Bacillus subtilis ZJF-1A5 in submerged fermentation (SMF). The process parameters influencing the enzyme production were identified by using response surface methodology. Among the variables screened, the temperature and time were most significant and showed a positive interaction. The optimum levels were: temperature 35.8 °C, pH 5.03 and time 54h and under these conditions α-amylase yield was up to 191.15 U/mL.

Abstract: In this paper, the theoretical flow ripple of an external gear pump is studied for pumps of similar size using different numbers of teeth on the driving and driven gears. External gear pumps with three different types of tooth profiles are studied. Nondimensional flowrates and fluctuation coefficients of gear pumps are discussed. By using the formula, flowrates can be calculated accurately and efficiently. Results indicate that: in the case of the same displacement (except teeth number and tooth width, other parameters of the gear pump are the same) the gear pump flow pulsation decreases with the increasing of the teeth number. We also concluded that changing tooth profiles on the driving and driven gear can get different pulse amplitude of the flow ripple.

Abstract: Supercritical carbon dioxide extraction (SCDE) technique was used to extract essential oils of Origanum vulgare L and Forsythia suspensa. The minimum inhibitory concentrations (MIC) of Origanum vulgare L essential oil and Forsythia suspensa essential oil used alone and in combination were determined by the same geometric dilution method, respectively. Then the synergistic antimicrobial effect of two essential oils was evaluated according to the calculated FIC values. The results showed that in light of the criteria of fractional inhibitory concentration (FIC), the combined use of Origanum vulgare L and Forsythia suspensa essential oils had synergistic effect on three bacteria (FIC=0.2-0.4) and on two mildews (FIC=0.1), and additive effect on two yeasts (FIC=0.8).

Abstract: In this paper, carbon nanotubes (CNT)-reinforced aluminum (Al) matrix composites were fabricated by High-Energy Ball Milling, the objective was to investigate the evolvement of particle size, density and hardness of CNT-Al composites with increasing wt% CNT, and analyzed the micrographs of mixture powders at different milling time. The results showed that the addition of CNT can play a role of grinding aid to refine grain, improve the hardness and decrease the density, and CNT can be homogeneous dispersed in the matrix with increasing ball-milling time, it also showed that too much CNT was no help on hardness, this attributed to clustering of CNT, the proper addition of CNT was 2wt%, and the mixture powders could reached a state of equilibrium between fracturing and cold-welding at 75min.

Abstract: The preparation of sweet potato starch phosphates which possess height stable paste was optimized in this study. A central composite design of response surface methodology involving phosphate (sodium dihydrogen phosphate and disodium hydrogen phosphate) concentration, the ratio of sodium dihydrogen phosphate and disodium hydrogen phosphate, phosphorylation temperature and urea concentration was used, and second-order model for paste stability was employed to generate the response surface. The optimum condition for preparation of sweet potato starch phosphates was as follows: phosphate concentration 4.89%, the ratio of sodium dihydrogen phosphate and disodium hydrogen 0.50, phosphorylation temperature 143°C, urea concentration 2.0%. The predicted value for paste stability of sweet potato starch phosphates at the optimum condition was 0.5721. Experimental verification gave values of 0.5708±0.0003.

Abstract: Bacillus subtilis cotA gene which was designed According to GenBank. cotA gene was transformed to Escherichia coli BL21(DE3). The recombined CotA protein was expressed by IPTG induced method. The CotA protein was stained red by syringaldazine after Native-PAGE.The effects of the condition of induction expression on enzyme production of recombinant Escherichia coli were investigated. The result showed that the highest enzyme activity of recombinant CotA could be achieved under the following conditions: the concentration of IPTG was 1.0 mmol L^-1, IPTG was added to the culture given a final concentration of 1.0 mol L^-1 when the OD₆₀₀ of culture reached 1.0, induction time was 12 h at 25°C. The CotA laccases could decolorize Remazol brilliant blue R (RBBR) and Congo red with 87% and Isatin and Crystal Violet with 55%. The result indicated that the CotA laccase had the potential to be industrial enzyme.

Abstract: This study was conducted to improve tenderness and overall qualities of goose breast meat using plant proteolytic enzymes from papaya, pineapple and ginger rhizome. The results showed that the optimum addition was: 0.12% papain, 6% pineapple juice and 4% ginger juice. Great differences were observed in water holding capacity of goose breast by the three solution treatment. The tenderness of goose breast by papain treatment was the best and the water loss rate, water holding capacity and hardness for 0.12% papain treated sample were 42%, 80% and 12542 g, respectively. SEM analysis results showed that the goose breast muscle fiber treated with 0.12% papain was only slightly fractured as compared with the control, but the muscle fiber treated by 6% pineapple juice or 4% ginger juice was seriously ruptured.