Advanced Materials Research Vol. 699

Abstract: The antioxidant activity of forty kinds of Chinese herbs extraction were evaluated by DPPH and FRAP assay. Eight kinds of them were found to possess strong antioxidant activity including Magnolia and Rhus chinensis Mill. and so on. The antioxidant activities of these Chinese herbs were determined after adding the pear wine by evaluating total polyphenols content using Folin-Ciocaileu method. The results showed that Magnolia and Rhus chinensis Mill. had high antioxidant activities in eight Chinese herbs in pear wine.

Abstract: The allelopathy of the exotic invasive plant, Solidago canadensis L. was studied. S. canadensis leaves were extracted with water and partitioned against ethyl acetate and n-butanol sequentially. The two organic fractions, original water extract and the residual water after the organic solvent extraction were tested for inhibitory activity on seed germination and seedling growth of wheat (Triticum aestivum), setaria (Setaria viridis) and its own species. Germination rate, vigor and index were recorded as germination parameters, and radicle and plumule growth and fresh weight of seedlings were recorded as seedling growth parameters. Results showed that the water extracts of S. Canadensis leaves had significant impacts on the seed germination and seedling growth of the three tested plants. n-Butanol fraction showed the strongest allelopathic effect, while the residual water after the organic solvent extraction had no significant phytotoxic effect compared with the control. n-Butanol fraction at 0.5 mg•ml-1 could significantly inhibited the seed germination of the same species, and that at 5 mg•ml-1 could significantly inhibited the seedling growth of the same species. n-Butanol fraction at 1.5 mg•ml-1 could significantly inhibited the seed germination and seedling growth of wheat. n-Butanol fraction at 5 mg•ml-1 could significantly inhibited the seed germination and seedling growth of setaria. The allelochemicals were mainly contained in n-butanol fraction of water extracts from S. canadensis leaves.

Abstract: To tackle the difficult problem of large ethnomedicine compound prescription research in a fast and efficient way, high-speed separation of Baimai prescriptions was performed by automated flash chromatography on 100-g Si flash columns at a flow-rate of 40 mL/min. Petroleum ether, methylene dichloride, ethyl acetate, methanol and water were used in gradient elution solvent system. 69 fractions were obtained as an ethnodrug compounds library. Separation degree of partial fractions were determined by HPLC-UV absorption spectrometry. Antioxidant activities screening of the fractions in 96 well plates was carryied out. Distribution range of fractions with strong scavenging effect of free radical DPPH was identified. Fraction 5-18 and 20 extracted from ethyl acetate exert the strongest antioxidant activities in vitro, and are identified as effective-composite of the prescription in radical scavenging. The results reported here suggest that the methods used may lead to improvements in the research and development of large ethnomedicine compound prescription.

Abstract: To research the effects and mechanisms of recombinant human ciliary neurotrophic factor (rhCNTF) on ischemia/reperfusion in vivo and in vitro, rhCNTF was biosynthesized, and ischemia/reperfusion-like models were used. Protection by rhCNTF was studied at the in vivo level using a model of middle cerebral artery occlusion and reperfusion (MCAO/R) in rats. RhCNTF was administrated just before reperfusion. RhCNTF markedly increased animal viability, decreased infarct volumes and neurological deficit scores. Primary cortical neuronal cultures were subjected to oxygen-glucose deprivation/reoxygenation, and treated with rhCNTF prophylactically. Results indicated that neuronal survival rates were increased, LDH release was decreased and lose of neurite length were alleviated in rhCNTF group, and this protection was associated with nerotrophic effect, nitric oxide and neuronal nitric oxide synthase (nNOS) and inducible NOS (iNOS). The data suggest that rhCNTF may be a good therapeutic reagent to reduce cerebral ischemia/reperfusion injury, and may act by NOS regulation.

Abstract: The polypeptide of Sipunculs nudus was prepared by papain. The optimum papain enzymolysis process to Sipunculs nudus was confirmed by means of single factor analysis and orthogonal test, it showed as below: 300U/g of enzyme addition amount, 50°C of temperature, 60min of enzymolysis time and pH7.0. The clearance rate of hydroxy radical is 95.42% according to the optimum process on Sipunculs nudus enzymolysis. The HPLC chromatogram showed that the prepared component of antioxidative active polypeptide according to such condition is single and its molecular weight is 5868. The results of experiment shows that Sipunculs nudus polypeptide have high inoxidizability and high removing free radicals ability.

Abstract: The cultivation of microalgae was studied experimentally in a glass semi-continuous photo-bioreactor. The effect of temperature, light intensity and light frequency on the growth rate of Isochrysis galbana was investigated in the work. The results showed that the optimum temperature and light intensity for the higher growth rate were 25°C and 18000 lux, respectively, the biomass productivity was 1.20×10-3g/(L•h). When the light frequency was 20hz,the the growth rate of I.galbana was the highest, which was 18.6% higher than that in continuous illumination..

Abstract: The waste polymer-polyethylene (PE) was treated in a supercritical water (SCW) system under different operation conditions (such as temperature, heat rate and ratio of water and PE material). The obtained liquid oil products and solid-products were analyzed by conjunct methods including high performance gel penetration chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC). A relationship of the characteristics of the products and the operation conditions in waste treatment was established. The results of FTIR and GC analyses indicated that the liquid oil products contain a large amount of alkanes, which are suitable for using as fuel oil. Through a series of experiments, the optimum operation conditions were defined as follows：The amount of PE sample: 6g, H2O/PE ratio: 6/1, the reaction temperature (Tem): 460° C, heating rate (Vt): 7.66 (°C / second), the yield of products: 86.0%.

Abstract: The decomposition pathways in CVD preparing SiC with CH3SiCl3-H2 precursors was searched theoretically, which involves 54 well-defined transition states. The geometries of the species were optimized by employing the B3PW91/6-311G(d,p) method. The transition states as well as their linked intermediates were confirmed with frequency and the intrinsic reaction coordinates analyses. The energy barriers and the reaction energies were evaluated with the accurate model chemistry method at G3(MP2) level after a non-dynamical electronic correlation detection. The heat capacities and entropies were obtained with statistical thermodynamics. The Gibbs free energies at 298.15 K and 1200 K for all of the reactions were reported. The energies at any temperature could be derived classically by using the analytical heat capacities. All the possible elementary reactions, including both direct decomposition and the radical attacking dissociations for CH2SiCl3, CH3SiCl2 and CH2SiCl2 were examined. A free radical reaction mechanism was proposed.

Abstract: We report on the effect of high repetition pulsed laser annealing with a KrF excimer laser on the optical properties of phosphorus ion-implanted ZnO nanorods. The recovery levels of phosphorus ion-implanted ZnO nanorods have been measured by photoluminescence spectra and cathode luminescence (CL) images. After ion implantation on the surface of ZnO nanorods, CL was disappeared over 400 nm below the surface due to the damage caused by ion implantation. When the annealing was performed at a low repetition, CL was recovered only shallow area below the surface. The depth of the annealed area was increased with the repetition rate of the annealing laser. By optimizing the annealing conditions such as the repetition rate, the irradiation fluence and so on, we have succeeded to anneal the whole damaged area over 400 nm in depth and to observe CL. Thus, the effectiveness of high repetition pulsed laser annealing on phosphorus ion-implanted ZnO nanorods was demonstrated.

Abstract: Nano-sized powders of dielectric CaCu₃Ti₄O₁₂ was synthesized by sol-gel reaction route. The powders are calcined at 700 °C and sintered at 1000 °C. The calcined powders diameter is in the range of 50 - 150 nm. Structural studies were carried out using the XRD, HRTEM and SEM. Frequency dependent dielectric properties were studied within the range of 20 Hz to 5 MHz. Molecular kinetics associated with dielectric relaxations is analyzed by Havriliak Negami function. It is found that the grain dipoles obey the Debye type of dielectric relaxation, while grain boundary dipoles follow the Cole-Cole type of dielectric relaxation. The observed grain and grain boundary dipole relaxation time are 6.598E-08 sec and 5.755E-04 sec, respectively.