Advanced Materials Research Vols. 634-638

Abstract: Liquid-liquid equilibrium tie-line data were examined at atmospheric pressure and at 298.15 K for ternary mixtures of (water + methanol + linalool) as well as (water + ethanol + linalool). The distribution ratios of alcohol between organic and aqueous phases are discussed. The immiscible area of (water + methanol + linalool) system is wider than that for the ethanol system. The experimental liquid–liquid equilibrium data were satisfactorily fitted by means of an extended UNIQUAC model.

Abstract: Two kinds of modified activated carbons were prepared by dipping with Zn(NO3)2 solution and by reducing in the atmosphere of N2 at high temperature respectively, which were characterized by FTIR,DSC,SEM and EDS. The surface structure was strongly changed in the process, along with the changes of chemical functional groups. The results of adsorption experiments revealed that the adsorbent capacities of UDMH gas at room temperature were enhanced obviously by modification compared with the raw activated carbon, especially dipped by transition metal solution. The mechanism probably involved was also discussed.

Abstract: A sequential optimization strategy, based on statistical experimental designs, was used to enhance the production of riboflavin by recombinant Bacillus subtilis X42. The two-level Plackett–Burman (PB) design was implemented to screen medium components that significantly influence riboflavin production. Among the 11 variables tested, glucose, yeast powder, MgSO4•7H2O, urea, CuCl2, MnCl2 were identified as the most significant factors (confidence levels above 95%) for riboflavin production. The selected significant parameters such as yeast powder, urea and CuCl2 were further optimized using a central composite design. The optimum medium was (in g/L): yeast powder, 20.8; urea, 4.8; CuCl2, 0.024; glucose, 100; MgSO4•7H2O, 0.5; K2HPO4, 0.5; KH2PO4, 1; FeCl2, 0.02. The optimum medium led to a maximum riboflavin concentration of 7.9 g/L in shake flasks, which was 11.2% higher than the control medium.

Abstract: In this work, a new bio-based hybrid polyamide (BDIS) was prepared and was cross-linked by dicumyl peroxide (DCP) with dose ranging from 1 to 7%. The state of cure was observed in vulcameter, and the vulcanization condition was determined subsequently. The cross-linking efficiency of BDIS/DCP blends was assessed using torque, gel content measurements and infrared spectroscopy (FTIR). DCP dose below 1% was not sufficient to reach gelation. Over 1%, the gel content increased with increasing DCP dose. The cross-linked BDIS films exhibited enhanced toughness and mechanical properties compared to precursors. Optimal mechanical properties were obtained with concentration of about 5 wt % DCP. At higher doses, the tensile strength and the elongation at break were decreased due to scission reactions.

Abstract: The photo-degradation process of cypermethrin in aqueous solution was studied using the laboratory-built photochemical degradation device and commercial high performance liquid chromatography (HPLC) with ultraviolet-visible absorbance detector and mass spectrometric detector. Spectrometric characteristics of cypermethrin and its main degradation products suggest that cypermethrin could be photo-degradated and converted into smaller molecular under ultraviolet irradiation. The photo-degradation reaction of cypermethrin in aqueous solution is approximately pseudo-first-order reaction. Light strength, pH and salinity have significant effects on the photo-degradaiton reaction of cypermethrin. Mass spectrometric results show that cypermethrin pesticide can be degraded into new and easily photochemical degrading products through the removal of chlorine.

Abstract: Microwave-assisted steam extraction system combines the advantages of both conventional and modern technologies. MAE is probably going to be the leading technology in essential oil producing industry. In our research, one-factor and uniform experimental designs are used to determine the optimum extraction conditions, and the results are as follows: the extraction yield is measured as 2.30% with 3h of reflux time, when degree of pulverization is 90, immersing time is 3h, yield of solid to liquid equals 12: 1 ml/g. The chemicals in the production were examined by GC-MS. More than 40 kinds of chemicals were detected, which is consistent with that of the traditional steam extraction method. However, the extraction efficiency is dramatically increased when the steam extraction is assisted with microwave heating, and it is up to 3.8 times.

Abstract: In this article, the selenium content of selenium polysaccharide and its antioxidant activity in vitro in Artemisia argyi has been studied. The double tracts atomic fluorescence spectrometry is used to detect the total selenium content in the sample and that of selenium polysaccharide in the active ingredient of the sample. The salicylic acid method and pyrogallol autoxidation method are used to detect the scavenging activity of selenium polysaccharide on hydroxyl radicals and superoxide anion. which grows in Yutangba, a selenium mining area of Enshi—“City of Selenium in China”. Through a comparative experiment with Artemisia argyi growing in non-selenium mining areas, the results have shown that the antioxidant ability of selenium polysaccharide in Se-enriched Artemisia argyi is significantly stronger than that of pure polysaccharide. Therefore, Se-enriched Chinese herbal medicine is a good natural antioxidant, which is worthy of exploitation and utilization.

Abstract: The interaction between Rutin-Ce and Lysozyme was studied using fluorescence，absorption, and circular dichroism spectra under simulative physiological conditions. The fluorescence quenching data show the presence of the static quenching mechanism. The binding constants (KA) are 1.14×104（298K）, 8.67×103（303K）, and 4.57×103（308K）L•mol-1, the binding sites (n) are approximately to1. The thermodynamic parameters (ΔHθ and ΔSθ) for the reaction further indicate both Van der Waals force and hydrogen bonds played key roles in the interaction accroding to Ross’s theory. The analyses of synchronous fluorescence spectra and CD spectra revealed Lysozyme conformation change in the presence of Rutin-Ce. The results provide some valuable information for Rutin drug design and pharmaceutical research.

Abstract: The binding of ofloxacin with human telomeric G-quadruplex DNA, Htel-G4-DNA and Htel-3-G4-DNA were examined by Fluorescence and CD spectroscopic methods. In the Fluorescence emission spectral analysis, the addition of ofloxacin induced significant quenching on the fluorescence emission of TO-G4-DNA complex. The fluorescence spectral analysis indicated that ofloxacin exhibited higher binding affinity and binding intensity to Htel-G4-DNA than Htel-3-G4-DNA. In the CD spectral analysis, the interaction with ofloxacin did not disturb the characteristic absorption of Htel-G4-DNA at 290 nm corresponding to its antiparallel form, and only slightly increased the positive absorption at 270 nm as shoulder peak, which suggests the antiparallel structure of G-quadruplex can remain stable in the presence of ofloxacin

Abstract: With black beans as raw materials, different factors on natural black beans peptide yield influence, and through the establishment of DPPH • system, OH • system, reducing power system measurement for the determination of different concentration of black soya bean peptide oxidation stability. The results showed that the liquid material ratio 17.5,leaching 42°C,extracting 55 min, black beans peptide extraction is 2.386 mg/g. Black beans peptide in various system all have certain oxidative stability, in the concentration of 0.04mg/ml to 74.05% clearance of DPPH• , in 0.06mg/ml concentration of OH•clearance rate is 80.48%, 0.08 mg/ml concentrations reduction force is 0.745, and in these three system natural black beans peptide oxidation stability are better than those of contrast VC is strong .