Morphology development and crystallization behavior of a poly(ethylene terephthalate)/polycarbonate blend

The morphology development and crystallization behavior of an extruded poly(ethylene terephthalate)/polycarbonate blend were studied with optical microscopy, light scattering, and differential scanning calorimetry (DSC). During annealing at 280°C, liquid–liquid phase separation via spinodal decomposition proceeded in a melt‐extruded specimen. After the formation of the domain structure, the blend slowly underwent phase homogenization by transesterification between the two polymers. The specimen, annealed for various times (t_s's) at 280°C, was subjected to a temperature drop to 180°C for the isothermal crystallization, and then the effects of liquid‐phase changes on crystallization were investigated. The crystal growth rate decreased with t_s. The slow crystallization with a large t_s value was associated with the composition change of the separated phases and the change of the sequence distribution in the polymer chains during annealing. The influence of t_s on the endothermic behavior of the samples was examined. As t_s increased, the recrystallization rate was retarded during the DSC scan, displaying multiendothermic behavior. The DSC data also suggested that the increased level of transesterification would give rise to a higher number of species being rejected from the primary crystals, leading to enhanced secondary crystallization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

The effects of carbon monoxide on the adsorption of nitric oxide on polycrystalline platinum

The effets of carbon monoxide on the adsorption and desorption of nitric oxide on the surface of polycrystalline platinum foil have been studied using the technique of thermal desorption spectroscopy (TDS) under ultra high vacuum conditions It is suggested that the surface of polycrystalline platinum used in this study consists of Pt(111) plane Pt(100) plane and a small amount of high index surfaces. The α-CO preadsorbed at 300 K prevents inderectly nitric oxide from adsorbing on the sites of the surface giving α-No peak. The repulsive force between α-CO and α-NO is very strong but a small amount of α-NO adsorbs even on the surface of platinum saturated by 50 L CO. The adsorption sites for β-CO coincide with those for β-NO and predosing with more than 10 L CO blocks entirely the adsorption sites for β-NO. β-NO reacts readily with CO producing carbon dioxide and molecular nitrogen and the reaction between CO and NO proceeds via Langmuir-Hinshelwood mechanism.     

Effect of seed moisture content on the grinding kinetics,yield and quality of soybean oil

Grinding kinetics of soybeans at different moisture content (6%, 8% and 12%) were investigated. The hardness of soybean particles increased and showed brittle characters as the moisture content decreased. Three theoretical models for grinding, such as the Rittinger, Kick, and Bond model, were applied to characterize the grinding process of soybeans. The lower moisture content showed less grinding constants including Bond’s work index. Sigmoid model was successfully applied to describe the changes in particle size of soybeans at different moisture contents during grinding (r² > 0.96). The TBARS (thiobarbituric acid reactive substances) at different size of soybean flours were measured at 25 °C and 50 °C for 20 days and the yield of oil composition at different size of soybean flours were measured. As the particle sizes decreased, the TBARS values increased during storage, while the oil yield from soybean flours increased.     

Quality comparison of dried slices processed from whole persimmons treated with different deastringency methods

The effects of different deastringency treatments (untreated, carbon dioxide, warm water, or ethanol), before drying on the quality characteristics of dried fruit slices prepared from whole “Cheongdobansi” persimmons were evaluated. L* (lightness) and a* (redness) values of dried slices from warm water- and ethanol-treated groups were higher, respectively, compared to that of dried slices from other groups. Hardness was lower in dried slices from ethanol-treated fruits. Moisture, water activity, soluble solids, titratable acidity, and sensory properties (color, aroma, texture, sweetness, and overall acceptability) of the dried slices from astringency-removed fruits were higher when compared to those of the dried slices from non-treated persimmons. In particular, the dried slices from ethanol-treated fruits showed the highest values for these parameters. Moreover, soluble tannin and DPPH radical scavenging activity decreased by deastringency treatment. Results suggest that ethanol deastringency treatment before drying could be a useful method to improve most quality characteristics, except antioxidative activity, of dried persimmon slices.     

Image enhancement based on signal subspace approach

This paper describes a block-by-block basis image enhancement algorithm which uses the signal subspace method to enhance images corrupted by uncorrelated additive noise. The enhancement is performed by eliminating the noise components in the noise subspace and estimating the clean image from the remaining components in the signal subspace.     

Thermoviscoelastic Behavior of Film‐Insert‐Molded Parts Prepared under Various Processing Conditions

Film‐insert‐molded (FIM) tensile specimens were prepared under various molding conditions to investigate the effects of wall temperature and packing pressure on the residual stress distribution and thermoviscoelastic deformation. The warpage of the specimen increased with increasing mold‐wall temperature difference and decreased with increasing packing pressure. The FIM specimens produced with unannealed films showed the warpage reversal phenomenon (WRP) during annealing and the degree of WRP was affected significantly by the molding conditions and thermal shrinkage of the film. The warpage of the specimen was predicted by three‐dimensional flow and stress analyses and the prediction was in good agreement with the experimental results.

     

Japanese bog orchid (Eupatorium japonicum) extract suppresses expression of inducible nitric oxide synthase and cyclooxygenase-2 induced by toll-like receptor agonists

Toll-like receptors (TLR) play an important role in the recognition of many pathogen-associated molecular patterns and the induction of innate immunity. Dysregulated activation of TLR signaling pathways is associated with certain inflammatory diseases. Japanese bog orchid (Eupatorium japonicum), which belongs to a family of Asteraceae plants, is consumed as a tea. The present study investigated the effect of the ethanol extracts of flowers of Japanese bog orchid (EJE) on nuclear factor (NF)-κB activation and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) by TLR agonists in murine macrophages. EJE suppressed NF-κB activation and iNOS and COX-2 expression induced by lipopolysaccharide (TLR4 agonist), polyriboinosinic polyribocytidylic acid (TLR3), and macrophage-activating 2 kDa lipopeptide (TLR2 and TLR6). These results suggest that EJE can regulate TLR signaling pathways and indicated its potential as a potent anti-inflammatory drug.     

Stevia rebaudiana Bertoni extract supplementation improves lipid and carnitine profiles in C57BL/6J mice fed a high‐fat diet

BACKGROUND: Stevia (Stevia rebaudiana Bertoni) is a non‐caloric natural‐source alternative to artificially produced sugar substitutes. This study investigated the effect of stevia extract on lipid profiles in C57BL/6J mice. Forty mice were divided into four groups: N‐C (normal diet and distilled water), H‐C (high‐fat diet and distilled water), H‐SC (high fat diet and sucrose, 1 mL kg^?1 per day), and H‐SV (high‐fat diet and stevia extract, 1 mL kg^?1 per day). RESULTS: Body weight gain was significantly higher in the H‐SC group than in the H‐SV group. Triglyceride concentrations in serum and liver were lower in the H‐SV group than in the H‐SC group. Serum total cholesterol concentrations were lower in the H‐SV and H‐C groups compared to the H‐SC group. The concentrations of acid‐insoluble acylcarnitine (AIAC) in serum were higher in the H‐SV group than in the H‐C and H‐SC groups and the acyl/free carnitine level in liver was significantly higher in the H‐SV group than in the N‐C group. These results were supported by mRNA expression of enzymes related to lipid metabolism (ACO, PPARα, ACS, CPT‐I, ACC) assessed by real‐time polymerase chain reaction. CONCLUSION: These results suggest that the supplementation of stevia extract might have an anti‐obesity effect on high‐fat diet induced obese mice. Copyright © 2010 Society of Chemical Industry     

Antioxidant activities and phenolic compounds of pigmented rice bran extracts

This study was carried out to investigate the antioxidant activities and phenolic compounds of pigmented rice (black, red, and green rice) and brown rice brans. Antioxidant activity was determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, 2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulfonic acid) (ABTS) radical cation assay, reducing power, and chelating ability. Phenolic compounds were measured by using HPLC. Pigmented rice brans were extracted by using aqueous mixtures of acetone, ethanol, and methanol to determine the most effective extraction solvent. Of all solvents examined, extract from 40:60 acetone-water mixtures (v/v) provided the highest DPPH radical assay as well as the highest total phenolic and flavonoid content. We finally selected 40% acetone as an extraction solvent for antioxidant study of pigmented rice bran. Antioxidant activities of 40% acetone extracts of pigmented rice bran, measured in the range of 0 to 1500 μg/mL. At 500 μg/mL concentration, red rice bran, which had the highest total phenolic (259.5 μg/mg) and total flavonoid (187.4 μg/mg) contents, showed the highest antioxidant activity: 83.6%, 71.5%, 1.2%, and 16.4% for DPPH radical assay, ABTS radical cation assay, reducing power, and chelating ability, respectively. Red rice bran showed a lower EC(50) value (112.6 μg/mL) than that of butylated hydroxytoluene (144.5 μg/mL) from the DPPH radical assay. The major phenolic acids of red rice bran were ferulic, vanillic and p-coumaric acids. The results indicated pigmented rice bran might be used as a natural antioxidant. PRACTICAL APPLICATION: The present study revealed black and red rice bran shows high antioxidant activities and they contain high amount of phenolic compounds. Indeed, black and red rice bran could be better raw materials for manufacturing the food with high antioxidant activity.     

A numerical and experimental study on the nonlinear behavior of laminated composite structural components

Nonlinear behavior of laminated composite plates and shells is studied. In the analysis, material nonlinearity due to the matrix degradation at the initial failure is considered along with the geometrical nonlinearity in the deformation process. An effective way of accounting the damage of the material due to initial failure is incorporated into a finite element analysis of the nonlinear behavior of the structural members. Experimental study is done on the filament-wound cylinders and laminated plates. The results are compared with the ones from the numerical analysis.