The permeability coefficients (P) of linalool, citral ethyl butyrate, d-limonene and octanal permeating through LDPE and ionomer films were measured alone as individual and as a component of a mixture at a temperature of 23 °C and in saturated water vapour. Values of P for ionomer film were approximately two orders of magnitude below those for LDPE for the compounds tested. Both PET and PETG films were found to be much better barriers against the compounds tested than LDPE and ionomer films. In general, the permeability, diffusion and solubility coefficients (P. D, and S) values measured in mixture were substantially less than the values obtained individually. Permeability behaviour of these compounds at low concentrations in the mixture was similar to that of permanent gases. Reduction of solubility coefficients in mixture permeation was greater with the higher solubility coefficients. These results provide a better understanding of the mechanism of vapour diffusion through polymers. 相似文献
The role of protein kinase C (PKC) in the induction of nitric oxide (NO) synthesis in murine peritoneal macrophages was examined. Phorbol ester, a PKC activator, had no effect on NO synthesis by itself, whereas IFN-gamma alone had modest activity. When phorbol ester was used in combination with IFN-gamma, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. This increase in NO synthesis was reflected as increased amount of inducible NO synthase (iNOS) mRNA, as determined by Northern blotting. The optimal effect of phorbol ester was shown at 6 h after treatment with IFN-gamma. Phorbol ester also induced the release of NO to the incubation medium by bacillus Calmette-Guerin-infected peritoneal macrophages. Prolonged incubation of cells with phorbol ester, which down-regulates PKC activity, abolished the synergistic cooperative effect on NO production with IFN-gamma. In addition, such PKC inhibitors as staurosporin or polymyxin B reduced NO production induced by IFN-gamma plus phorbol ester. When the cells were treated with both actinomycin D and phorbol ester after IFN-gamma stimulation, more NO was produced and more iNOS mRNA was expressed than in the cells treated with actinomycin D alone. On the basis of these observations, we conclude that PKC might not be directly involved in the expression of NO synthase, but, instead, might be involved in the stabilization of the iNOS mRNA already expressed by the treatment of IFN-gamma. 相似文献
Food Science and Biotechnology - Due to their numerous well-established applications in the food industry, there have been many studies regarding the adaptation and evolution of lactic acid... 相似文献
Light-section (LS)-based range finders are commonly used for obstacle recognition in home service robots and autonomous vehicles. This paper proposes a smart CMOS image sensor for LS-based range finding. The proposed sensor can detect the laser light, even under very strong ambient-illumination levels by using a multiple-capture frame-correlated double sampling (F-CDS), which is realized with an inverter-based switched-capacitor F-CDS accumulator. The proposed sensor also includes on-chip winner-take-all circuits that significantly reduce the software and hardware complexity of interpolation for the subpixel resolution. The prototype chip was fabricated using a 0.35-mum CMOS process. The measurement results show that the proposed sensor can detect a laser line with an intensity that is 56.5 dB lower than that of the ambient illumination, providing a spatial resolution of plusmn0.16 pixels. 相似文献
We have investigated a Cu-doped MoOx/GdOx bilayer film for nonvolatile memory applications. By adopting an ultrathin GdOx layer, we obtained excellent device characteristics such as resistance ratio of three orders of magnitude, uniform distribution of set and reset voltages, switching endurance up to 104 cycles, and ten years of data retention at 85degC. By adopting bilayer films of Cu-doped MoOx/GdOx, a local filament was formed by a two-step process. Improved memory characteristics can be explained by the formation of nanoscale local filament in the ultrathin GdOx layer. 相似文献
Tailor made : We report the rational biosynthesis of C15 hydroxylated non‐quinone geldanamycin analogues by site‐directed mutagenesis of the geldanamycin polyketide synthase (PKS), together with a combination of post‐PKS tailoring genes. Rational biosynthetic engineering allowed the generation of geldanamycin derivatives, such as DHQ3 illustrated in the figure, which had superior pharmacological properties in comparison to the parent compound.
Colloidal nanocomposite particles were prepared by heterocoagulation of carbon nanotubes (CNTs) dispersion stabilized by cationic hexadecyltrimethylammonium bromide (CTAB) and negatively charged poly(styrene-co-butyl acrylate), P(St-co-BA), latex prepared by conventional emulsion polymerization in aqueous medium with the aid of a flocculant, polyaluminium chloride (PAC), at elevated temperature above the Tg of P(St-co-BA). The hybrid nanocomposite particles were prepared by a simple procedure consisting of mixing two dispersions, particle growth, and stabilization steps. The effects of the surface properties of CNTs, molecular weight of latex polymer, types of flocculants and its optimum concentration were investigated. At a well-controlled condition, the spherical or potato-like particles in the size range of 10-100 μm were achieved. After film formation of the nanocomposite particles, it was able to confirm that CNTs were uniformly distributed without agglomeration in the matrix, resulting in the percolation at a low concentration of CNTs. 相似文献
Bi2O3 was added to a nominal composition of Zn1.8SiO3.8 (ZS) ceramics to decrease their sintering temperature. When the Bi2O3 content was <8.0 mol%, a porous microstructure with Bi4(SiO4)3 and SiO2 second phases was developed in the specimen sintered at 885°C. However, when the Bi2O3 content exceeded 8.0 mol%, a liquid phase, which formed during sintering at temperatures below 900°C, assisted the densification of the ZS ceramics. Good microwave dielectric properties of Q × f =12,600 GHz, ɛr=7.6, and τf=−22 ppm/°C were obtained from the specimen with 8.0 mol% Bi2O3 sintered at 885°C for 2 h. 相似文献
This study was conducted to determine the effect of the addition of kimchi powder on the quality characteristics of meat batter and breakfast sausage. Breakfast sausages were supplemented with freeze dried kimchi powder (FKP) or hot air dried kimchi powder (HKP) at levels of 1% (FKP-1 and HKP-1) or 2% (FKP-2 and HKP-2). The emulsion stability, cooking yield, and apparent viscosity in meat batters improved with increments of kimchi powder (p < 0.05). Increased levels of kimchi powder in breakfast sausage decreased the L∗ value, pH, and springiness, and increased the a∗ value, b∗ value, hardness, chewiness, and gumminess (p < 0.05). Sensory evaluations indicated that a higher overall acceptability was attained when the kimchi powder was added to breakfast sausage at a level of 2%. 相似文献