Advanced Materials Research Vols. 750-752

Abstract: Foam separation method was utilized to purify crude tea saponin. The factors influencing the purification were studied, including the effects of original concentration, airflow rate and loading liquid volume. By systematic experiments, the optimal purification technology was determined. Foam separation method showed great advantages such as: low solvent and energy consumption, convenience, environmental friendliness. This work provides useful information for tea saponin purification development.

Abstract: Liquid-solid extraction kinetics performance of flavonoids from okra (Abelmoschus esculentus L. Moench) pods was studied. The effects of temperature and solid to liquid ratio on the extraction kinetics of flavonoids were examined. The experimental extraction kinetics was established and analyzed with a mathematical model derived from Ficks second law following the first-order equation. Results explained that the mean relative error (MRE) values for temperature and liquid-solid ratio were low (3.84% and 4.70%, respectively). The model quality was determined by statistical comparison of the predicted and observed values. A good prediction (MRE < 5%) and concordance (the coefficient of determination, R² > 0.995) of the extraction model on experimental data and calculated values was observed. Hence, the initial rate, degree of extraction, rate constant and activation energy for the extraction model of flavonoids were estimated.

Abstract: In this paper nonlinear phenomenon of respiratory system is analyzed. Airway is partitioned into four parts by different morphology which causes different fluid dynamic character. Reasons that cause nonlinear phenomenon for different parts are given. To simplify the representation corresponding parameters is selected to compromise complicity and precision. Finally the suggested representation of respiratory system is summarized so that the model can be used easily in lung simulator.

Abstract: A pot trial with a soil-sand combination culture in rhizosphere bags was conducted to study the effects of applying Se in soil on formation of iron plaque outside roots, rice growth and absorption of Se and Cd under the control conditions. The results showed that application of low concentration Se (1.0 mg/kg) can promote the formation of iron plaque outside roots, but application of high concentration Se (8.0 mg/kg) can inhibit formation of iron plaque outside roots. Whether applying Cd or not, Se on rice growth had no significant effect, which explained Se on rice growth had not produced toxic effects. With the increasing of Se treatment concentrations, the Cd content of roots, stems, leaves, rice husks and rice significantly decreased. Application of selenium can improve the selenium content in rice, which explained rice had enrichment effect for selenium.

Abstract: A new powder material, rice husk-plastic composite powder (RPC), was successfully developed for selective laser sintering (SLS) process. RPC is mainly composed of rice husk powder and a hot-melt adhesive powder, it is a green and biological material and its most important advantage is low-cost, but because the hull surface of rice is burr and not smooth, easily jammed between particles, poor mobility, is not the medium of easy flowing, so mixing process was successfully developed to prepare RPC powders. The preparation process is divided to three steps. First, before mix, the rice husk power is dried for reducing the hydrophilic nature of rice husk fiber and improving the wettability and the adhesion actions of the interface. Then, put the PES hot melt adhesive, the dried wood powder and the acetone solution which contain coupling agent and initiator together to mix evenly. At last, dry the basic material at the constant temperature of 45±2°C in the oven, add the organic filler and light stabilizer. Finally, RPC powder for SLS is got. As the result of SLS fabrication, part made by RPC powder is got, its mechanical properties and dimensional accuracy is satisfied.

Abstract: Zein was added into wheat gluten (WG) to prepare zein composite films (ZCF) in order to improve the properties of films. The film-forming ability, properties, surface microstructure and infrared spectrum of WG films and ZCF were investigated. The results show that the viscosity of film-forming solutions decrease, and uniformity become worse slightly, after zein added. ZCF are yellow, with metal luster, whose toughness and water retention increase. Compared to the control, the ZCF tensile strength (TS), elongation at break (EB) and resistance of oxygen are increased by 33.2%, 17.2% and 11.25%, and water vapor permeability (WVP) and transparency are decreased by 26.0% and 75.4% respectively. ZCF have better antibacterial properties than WG films. The inhibition effect on escherichia coli and staphylococcus aureus are increased by 36.36% and 32.89% respectively. Hydrogen bond interaction of ZCF become weak, and the surface of ZCF become smooth and evenly.

Abstract: The chemical comcomposition and water prehydrolysis of moso bamboo were studied to prepare high grade dissolving pulp. The results indicated that the moso bamboo was an appropriate none-wood material for great dissolving pulp goten as its high cellulose content. By single factor method, the optimum prehydrolysis conditions which were 150°C, 120minutes and 1:8 of liquor-to-wood tatio, were obtained. Based on the optimum conditions, the yield was 90.35%, and the retention rate of cellulose, pentosan, acid accumulator insoluble lignin, and ash were respectively 96.30%, 88.22%, 88.13%, and 11.71%.

Abstract: The cordycepin was extracted from cultured cordyceps militaris through enzymatic method. The main factors: ratio of material to liquid, cellulose addition and extraction liquid were selected to carry out single factor experiment. The L₉(3⁴) orthogonal experimental design was applied to optimize extraction technology of cordycepin. The results showed that effects of three factors on cordycepin extraction rate reached extremely significant level. The optimum parameters of cordycepin extraction were material-liquid ratio 1:15, enzyme addition 1.5% and ethanol solution 50% under temperature 70°C for 3h. Under these parameters, cordycepin extraction rate reached to 1.48%. The antioxidant property of cordycepin were determined by hydroxyl radical (OH) and DPPH (1,1-diphenyl-2-picryl-hydrazyl) radicals scavenging assays. When cordycepin concentration was 0.8 and 1.8 mg/mL respectively, the scavenging capacity of DPPH and OH could reach to 50%. The antioxidant property of cordycepin was close to vitamin C. This study has important practical significance for deep processing of Cordyceps militaris resources.

Abstract: Long surgical incisions required application of more flexible cyanoacrylate adhesive to relieve skin tension. A new formulation of octyl-2-cyanoacrylate (OCA) was modified by 0%, 3%, 6% and 9% (w/v) polytrimethylene carbonate (PTMC). The OCA/PTMC adhesives showed higher viscosity and bond strength than OCA monomer. The OCA/6% PTMC adhesive plus subcutaneous suture was used as group A (Treatment group), and the OCA/6% PTMC tissue adhesive alone was used as group B (Control group). 30 days later, there was no apparent scar formation in group A. A linear scar formation still could be seen in group B. The results supported the use of OCA/6% PTMC adhesive alone or adhesive plus subcutaneous suture in long surgical incisions, and the latter maintained better scar formation.

Abstract: Biomaterial is one of the good candidates for porous membrane preparation according to its environmental friendliness. In this work, the porous membranes of silk fibroin (SF) were prepared by solution casting with the addition of polyethylene glycol (PEG) and glutaraldehyde (GTA) aiming to improve the porosity and oxygen permeability of SF membrane. The conformation of SF was changed from random coil to β sheet form after treatment with MeOH. The interaction existing between SF chains and both PEG and GTA were characterized using Fourier Transform Infrared spectroscopy (FT-IR). The addition of PEG could produce more porosity in the membrane than GTA confirmed by their morphology observed from scanning electron microscopy (SEM). Moreover, the swelling behavior of the SF-PEG and SF-GTA membranes depended on the porous structure of the membrane which directly correlated to their oxygen permeability. The porosity of the SF membranes increased with the increase of PEG and GTA contents up to 40% and 3%w/w, respectively. After that, their porosity decreased as seen through the SEM and water swelling results. In addition, the SF-PEG membrane turned out to have higher degrees of both porosity and oxygen permeability than the SF-GTA membrane which related to its water swelling behavior.