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711.
Okada K Hasegawa F Kameshima Y Nakajima A 《Journal of materials science. Materials in medicine》2007,18(8):1605-1612
Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites
but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the
advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio.
Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of
the ceramic powder while maintaining bioactive activity, CaSiO3/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In
methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO3 powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA
substrate in method (2). In method (3), CaSiO3 powder was surface loaded on to a PLA substrate by hot-pressing. The bioactivity of these samples was investigated in vitro
using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite
formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2),
apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness
of the resulting apatite layers becoming about 20 μm after soaking for 14 days. Since the amount of CaSiO3 powder used in these samples was only ≤0.4 vol%, it is concluded that this preparation method is very effective in generating
bioactivity in polymer-matrix composites by loading with only very small amounts of ceramic powder. 相似文献
712.
Simplified regression models to evaluate site amplification are widely adopted for seismic microzonation maps, design specifications, and so forth. In practice, the most popular parameter for controlling the evaluation models is an averaged S-wave velocity of top z m depth, VSz, especially VS30. The S-wave impedance ratio of the uppermost layer to the base layer, IS1/IS0, is an alternative evaluation parameter. In this study, we compare the evaluation performance of VSz and IS1/IS0 for SH wave amplification factors on the basis of numerical experiments on artificially generated soil profiles. Taking the average S-wave velocity, depth z must be selected on the basis of the target period range of the site amplification factors. IS1/IS0 is found to perform similarly to VS10, and it is better than VS30 for the peak ground acceleration (PGA) and the short-period range (0.1–0.5?s). This implies that IS1/IS0 is effective for use in site amplification evaluations because IS1 only requires a physical parameter on the uppermost surface layer. 相似文献
713.
In glycomics, mass spectrometry is an indispensable tool for high throughput analyses. Generally speaking, glycans contain many hydroxyl groups and are more difficult to ionize than peptides. Derivatization of glycans has been useful for increasing sensitivity. However, it takes time to purify and causes loss of sample. Here, we show a highly sensitive aminoquinoline (AQ)-labeling method of glycans on a matrix-assisted laser desorption/ionization (MALDI) target using a liquid matrix 3-aminoquinoline (3-AQ)/α-cyano-4-hydroxycinnamic acid (CHCA). It is a rapid procedure and reduces loss of sample material during the reaction process, especially in negative ion mode where 10 amol of monosialylated N-glycan were detected as AQ-labeled molecular ions. In addition, MS/MS of 10 amol of monosialylated N-glycan was achieved. 相似文献
714.
Yoshihito Maeda Kazumasa NarumiSeiji Sakai Yoshikazu TeraiKohei Hamaya Taizoh SadohMasanobu Miyao 《Thin solid films》2011,519(24):8461-8467
We have investigated perfection of atomic rows on iron-based Heusler alloy films on Ge(111) planes by using ion channeling technique in order to find the dominant factors for the perfection. Fe3Si/Ge(111) and Fe2CoSi/Ge(111) have a high quality of atomic rows at the heterointerface like that of perfect crystals. Fe3−xMnxSi/Ge(111) (x = 0.84, 0.72 and 0.36) interfaces have imperfection of atomic rows which may be controlled by both the lattice mismatch with the Ge substrate and the Mn-Si pairs due to the site disorder in the film with the Mn content x > 0.75. Analysis of axial channeling parameters employed in this study is very useful for quantitative evaluation of perfection of atomic rows at the heterointerface. 相似文献
715.
Yu You Makoto Ohtsuka Hideto Miyake Hiroyuki Fukuyama 《Journal of the American Ceramic Society》2014,97(12):3781-3786
The growth of AlN crystals on c‐plane 6H–SiC substrates by thermal nitridation of Al2O3 pellets in the presence of graphite and ZrO2 was demonstrated. Addition of graphite and ZrO2 effectively accelerated the evaporation of Al2O3, yielding c‐axis oriented AlN films on SiC substrates. The SiC substrate was severely deteriorated at 2173 K, which produced a porous interface between the AlN film and substrate, resulting in low‐quality AlN crystals. The deterioration of SiC was successfully suppressed by introducing a pre‐deposited homo‐buffer layer, allowing two‐dimensional‐like growth of AlN. The buffer layer promoted the formation of a high‐quality AlN film. At 2173 K, the full‐width at half maximum of the X‐ray rocking curves of the (0002) and (10–10) planes of the AlN film was 360 and 425 arcsec, respectively. 相似文献
716.
Tokuoka Y Suzuki M Ohsawa Y Ochiai A Ishizuka M Kawashima N 《Drug development and industrial pharmacy》2008,34(6):595-601
Enhancing effect of l-menthol and its derivatives, l-menthyl formate, l-menthyl acetate, and l-menthyl propionate, on skin permeation of 5-aminolevulinic acid (ALA) through Yucatan micropig full-thickness skin was investigated using a Franz-type diffusion cell. ALA solutions were prepared using ethanol-water mixed solvents with l-menthol or the derivative. Skin permeation coefficients (Kp) of ALA with more than 3.0 wt% of l-menthol was significantly larger than that without l-menthol. In addition, Kp of ALA with the derivative increased as follows: l-menthol approximately l-menthyl propionate < l-menthyl formate < l-menthyl acetate. These results suggest that l-menthol and the derivative are effective to enhance ALA skin permeation. 相似文献
717.
A method of rapidly identifying and imaging suspended nanotubes by scanning electron microscopy is reported. Nanotubes are visible in high contrast and even at low magnification. The contrast can be explained by considering the effect that the charge on the nanotube has on the substrate. The proposed mechanism is general and should apply to any charged nanostructure in proximity to a surface or interface. This represents a new contrast mechanism in scanning electron microscopy. 相似文献
718.
The photoluminescence (PL) spectra of suspended single-walled carbon nanotubes (SWNTs) were measured in an ethanol gas atmosphere. When the gas pressure was decreased, the PL peaks were initially blue-shifted to a small extent before a rapid blue-shift took place at a transition pressure that depended on the temperature and diameter of the SWNT being measured. This pressure dependence is due to the adsorption of ethanol molecules on the SWNT surface. The optical transition energies measured below the transition pressure are intrinsic to the SWNT. 相似文献
719.
Omori Y Sakikubo T Nakane M Fuchu H Miake K Kodama Y Sugiyama M Nishikawa Y 《Journal of food protection》2010,73(10):1803-1808
To manufacture raw ham in an efficient manner, we recently developed a new system in which presliced pork loin was used, and the processing time was reduced to 5% of the conventional method. This study aimed to examine whether this raw ham could be as safe as ham produced by the conventional method. Pork loin spiked with enterohemorrhagic Escherichia coli serotype O157:H7, Listeria monocytogenes serotype 1/2c, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus were processed using either the new or conventional method. The fate of the foodborne pathogens and behavior of hygiene indicator bacteria were examined. Whereas nitrite had disappeared during the conventional packaging process, the reduced processing time in the new system allowed for the ham to be vacuum packed with retention of the nitrite (6.9±1.2 ppm, P<0.01). This accounts for the prominent decrease in L. monocytogenes (2.3 log reduction in 35 days) and S. aureus (3.3 log reduction in 13 days) counts during storage. E. coli O157 and Salmonella Enteritidis were likely resistant to the nitrite in the ham. However, they were unable to multiply in the ham and decreased gradually as in the conventionally produced ham. The bacteriostatic nature of the raw ham was also indicated by the gradual decrease in coliforms (1.3 log reduction in 13 days) in nonspiked ham. In conclusion, the raw ham produced using presliced pork loin is practically as safe as conventionally produced raw ham. It is worth validating these results in a small-scale production setting. 相似文献
720.
Hotta A Saito Y Kyogoku K Kawabe Y Nishijima K Kamihira M Iijima S 《Journal of Bioscience and Bioengineering》2006,101(4):361-368
The production of retroviral vectors using a transient expression system has been improved to obtain a high-titer virus preparation that is difficult to produce using packaging cell lines due to the cytotoxic or cytostatic effect of transgenes. Here, we used one such production method, the so-called Q-vector system, and examined its potential for virus production. The Q-vector system could produce a similar level of viral vectors compared with the packaging cell system but the production seemed to depend on the size and nature of transgenes. In the process of investigation of the quantitative difference in viral components between the transient expression system and the packaging cell system, we found that the Q-vector system could express higher amounts of viral RNA and proteins compared with the packaging cell system. However, this did not lead to a higher virus titer compared with that produced by the packaging cell system. This suggests that retroviral RNA transcribed from the plasmid in the transient system seemed to be used mainly for translation and only some of the RNA molecules were packaged in viral particles. 相似文献