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91.
The possibility of producing the biologically active material of the skin, ceramide, was studied using yeasts. The yeast strain
that produced the most ceramide, Saccharomyces cerevisiae (KCCM 50515), was selected, and the optimal conditions for ceramide production were determined using shakeflask culture and
batch fermentation. By measuring the production rate of ceramide at various pH values and temperatures, the optimal conditions
for ceramide production were found to be pH 6.0 and 30°C. When heat shock was applied to the cells for 1 h by increasing the
culture temperature from 30 to 40°C after cell growth, the amount of ceramide produced was increased 5.9-fold. A cell growth
and ceramide production model was developed with Monod kinetics and the Leudecking-Piret model. It showed that ceramide production
was increased when the cells were in the stationary phase. 相似文献
92.
Millaruelo M Eichhorn KJ Sieczkowska B Voit B 《Langmuir : the ACS journal of surfaces and colloids》2006,22(22):9436-9445
We present the synthesis and characterization of a series of photolabile phenacyl derivative polymers and their subsequent thin film preparation. These systems are composed of up to three methacrylate units: a photolabile component including a p-methoxyphenacyl moiety which after selective irradiation (UV/laser) can provide free carboxylic groups in specific areas for further modification; an anchoring unit, trimethoxysiloxane or glycidyl methacrylate derivative, which allows the covalent attachment of the polymer to the substrate; and a spacer, methyl methacrylate or styrene, which in the appropriate proportion ensures the formation of films with good quality. Structural and thermal properties of these materials have been analyzed by means of NMR, FTIR, elemental analysis, UV, gel permeation chromatography, differental scanning calorimetry, and thermogravimetric analysis. The polymers have been subsequently processed by spin coating to render ultrathin films (<50 nm). Topographic and structural characterization studies of the films have been carried out with atomic force microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. The extent of the substrate attachment of the polymers depending on the nature of the anchoring groups have been studied by ellipsometry and FTIR. 相似文献
93.
Xu C Kim D Chun J Rho K Chon B Hong S Joo T 《The journal of physical chemistry. B》2006,110(43):21741-21746
Starting from a mixture of Zn and BiI3, we grew nanowires and nanoplates on an oxidized Si substrate at relatively low temperatures of 250 and 300 degrees C, respectively. The ZnO nanowires had diameters of approximately 40 nm and grew along the [110] direction rather than the conventional [0001] direction. The nanoplates had thicknesses of approximately 40 nm and lateral dimensions of 3-4 microm. The growth of both the nanowires and nanoplates is dominated by the synergy of vapor-liquid-solid (VLS) and direction conducting. Analysis of photoluminescence spectra suggested that the nanoplates contain more oxygen vacancies and have higher surface-to-volume ratios than the nanowires. The present results clearly demonstrate that the shapes of ZnO nanostructures formed by using BiI3 can be controlled by varying the temperature in the range 250-300 degrees C. 相似文献
94.
We suggest that the "new form of matter" found just above T(c) by the Relativistic Heavy Ion Collider is made up of tightly bound quark-antiquark pairs, essentially 32 chirally restored (more precisely, nearly massless) mesons of the quantum numbers of pi, sigma, rho, and a1. Taking the results of lattice gauge simulations (LGS) for the color Coulomb potential from the work of the Bielefeld group and feeding this into a relativistic two-body code, after modifying the heavy-quark lattice results so as to include the velocity-velocity interaction, all ground-state eigenvalues of the 32 mesons go to zero at T(c) just as they do from below T(c) as predicted by the vector manifestation of hidden local symmetry. This could explain the rapid rise in entropy up to T(c) found in LGS calculations. We argue that how the dynamics work can be understood from the behavior of the hard and soft glue. 相似文献
95.
96.
Journal of Visualization - Schlieren visualization of the plume ejected from the microgas turbine nozzle was conducted to understand infrared signal characteristics of various shapes of the exhaust... 相似文献
97.
Abstract: A three step synthesis of the advanced glycosylation endproduct 2-(2′-furoyl)-4(5)-(2′-furanyl)-1H-imidazole (4, FFI) has been achieved from 2-acetylfuran. The key step in the synthesis was the rearrangement of the hydrazinium bromide 3 in refluxing methanol. 相似文献
98.
99.
Cho DY Kim JY Park BG Rho KJ Park JH Noh HJ Kim BJ Oh SJ Park HM Ahn JS Ishibashi H Cheong SW Lee JH Murugavel P Noh TW Tanaka A Jo T 《Physical review letters》2007,98(21):217601
We investigated electronic structure of hexagonal multiferroic YMnO3 using the polarization dependent x-ray absorption spectroscopy (XAS) at O K and Mn L(2,3) edges. The spectra exhibit strong polarization dependence at both edges, reflecting anisotropic Mn 3d orbital occupation. Moreover, the O K edge spectra show that Y 4d states are strongly hybridized with O 2p ones, resulting in large anomalies in Born effective charges on off-centering Y and O ions. These results manifest that the Y d(0)-ness with rehybridization is the driving force for the ferroelectricity, and suggest a new approach to understand the multiferroicity in the hexagonal manganites. 相似文献
100.