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排序方式: 共有1388条查询结果,搜索用时 15 毫秒
41.
Tsutomu Osawa Masashi Ando Saori Sakai Tadao Harada Osamu Takayasu 《Catalysis Letters》2005,105(1-2):41-45
The role of acetic acid added to the reaction media for the enantio-differentiating hydrogenation of methyl acetoacetate over
a (R,R)-tartaric acid-in-situ-modified nickel catalyst was studied from the viewpoint of the hydrogenation rate during repeated
runs. The hydrogenation of methyl acetoacetate on the “enantio-differentiating sites” of a tartaric acid-modified nickel catalyst
was specifically accelerated by the acetic acid added to the reaction media to increase the enantio-differentiating ability
of the catalyst. In order to increase the enantio-differentiating ability, the addition of acetic acid to the reaction media
was required in each run during the repeated use of the catalyst. 相似文献
42.
The sex pheromones of four Plusiinae species in the family Noctuidae, Ctenoplusia albostriata (CA), Macdunnoughia purissima (MP), Syngrapha ain (SA), and Diachrysia stenochrysis (DS) were identified by GC-EAD and GC-MS analyses. These were subsequently evaluated by a series of field trials in different ecological habitats. CA females produced (Z)-5-decenyl acetate (I), (Z)-7-dodecenyl acetate (II), and (Z)-7-dodecen-1-ol (III) in a ratio of 2:100:13. While the antennae of CA males responded to all three components, neither I nor III was essential to capture males. The MP females produced II, III, and (Z)-5-dodecenyl acetate (IV) in a ratio of 100:80:20, and this blend captured the most MP males. Compounds II and III were also identified from SA females, and mixtures ranging from 4:1 to 2:3 were equally attractive to males. DS females only produced one active compound, (Z)-7-decenyl acetate (V), and DS is the first Plusiinae species identified as using only the ω3-compound and none of ω5-compounds, such as II and III, which are common components of Plusiinae pheromones. Using previously published chemical and biosynthetic data, together with the finding from this study, we propose a classification of the Plusiinae sex pheromones. 相似文献
43.
Christopher J. Marvel Qirong Yang Scott D. Walck Kelvin Y. Xie Kristopher D. Behler Jerry C. LaSalvia Masashi Watanabe Richard A. Haber Martin P. Harmer 《Journal of the American Ceramic Society》2022,105(5):2990-3007
Compositional analysis of boron carbide on nanometer length scales to examine or interpret atomic mechanisms, for example, solid-state amorphization or grain-boundary segregation, is challenging. This work reviews advancements in high-resolution microanalysis to characterize multiple generations of boron carbide. First, ζ-factor microanalysis will be introduced as a powerful (scanning) transmission electron microscopy ((S)TEM) analytical framework to accurately characterize boron carbide. Three case studies involving the application of ζ-factor microanalysis will then be presented: (1) accurate stoichiometry determination of B-doped boron carbide using ζ-factor microanalysis and electron energy loss spectroscopy, (2) normalized quantification of silicon grain-boundary segregation in Si-doped boron carbide, and (3) calibration of a scanning electron microscope X-ray energy-dispersive spectroscopy (XEDS) system to measure compositional homogeneity differences of B/Si-doped arc-melted boron carbides in the as-melted and annealed conditions. Overall, the improvement and application of advanced analytical tools have helped better understand processing–microstructure–property relationships and successfully manufacture high-performance ceramics. 相似文献
44.
Kami D Takeda S Itakura Y Gojo S Watanabe M Toyoda M 《International journal of molecular sciences》2011,12(6):3705-3722
Nanoparticle technology is being incorporated into many areas of molecular science and biomedicine. Because nanoparticles are small enough to enter almost all areas of the body, including the circulatory system and cells, they have been and continue to be exploited for basic biomedical research as well as clinical diagnostic and therapeutic applications. For example, nanoparticles hold great promise for enabling gene therapy to reach its full potential by facilitating targeted delivery of DNA into tissues and cells. Substantial progress has been made in binding DNA to nanoparticles and controlling the behavior of these complexes. In this article, we review research on binding DNAs to nanoparticles as well as our latest study on non-viral gene delivery using polyethylenimine-coated magnetic nanoparticles. 相似文献
45.
Tsunenori Watanabe Yoshihisa MikiTakeo Masuda Hiroshi DeguchiHiroyoshi Kanai Saburo HosokawaKenji Wada Masashi Inoue 《Ceramics International》2011,37(8):3183-3192
Synthesis of the γ-Ga2O3-Al2O3 solid solutions by spray pyrolysis was examined. Spherical particles were obtained using an aqueous solution of Al(NO3)3 and Ga(NO3)3 with HNO3. For Ga-rich composition, γ-phase solid solutions were directly crystallized by the spray pyrolysis. For Al-rich composition, spray pyrolysis gave amorphous products unless a sufficient thermal energy was supplied during the spray pyrolysis. Subsequent calcination of the amorphous products gave γ-Ga2O3-Al2O3 solid solutions. However, physical properties of the solid solutions were affected by the spray pyrolysis conditions. 相似文献
46.
Cancer chemopreventive ability of conjugated linolenic acids 总被引:1,自引:0,他引:1
Tanaka T Hosokawa M Yasui Y Ishigamori R Miyashita K 《International journal of molecular sciences》2011,12(11):7495-7509
Conjugated fatty acids (CFA) have received increased interest because of their beneficial effects on human health, including preventing cancer development. Conjugated linoleic acids (CLA) are such CFA, and have been reviewed extensively for their multiple biological activities. In contrast to other types of CFAs including CLA that are found at low concentrations (less than 1%) in natural products, conjugated linolenic acids (CLN) are the only CFAs that occur in higher quantities in natural products. Some plant seeds contain a considerably high concentration of CLN (30 to 70 wt% lipid). Our research group has screened CLN from different plant seed oils to determine their cancer chemopreventive ability. This review describes the physiological functions of CLN isomers that occur in certain plant seeds. CLN are able to induce apoptosis through decrease of Bcl-2 protein in certain human cancer cell lines, increase expression of peroxisome proliferator-activated receptor (PPAR)-γ, and up-regulate gene expression of p53. Findings in our preclinical animal studies have indicated that feeding with CLN resulted in inhibition of colorectal tumorigenesis through modulation of apoptosis and expression of PPARγ and p53. In this review, we summarize chemopreventive efficacy of CLN against cancer development, especially colorectal cancer. 相似文献
47.
Hiromi Nabeshi Tomoaki Yoshikawa Akihiro Arimori Tokuyuki Yoshida Saeko Tochigi Toshiro Hirai Takanori Akase Kazuya Nagano Yasuhiro Abe Haruhiko Kamada Shin-ichi Tsunoda Norio Itoh Yasuo Yoshioka Yasuo Tsutsumi 《Nanoscale research letters》2011,6(1):1-6
In this study, complexes composed of poly-l-tyrosine (pLT) and single-walled carbon nanotubes (SWCNTs) were produced and the dispersibility of the pLT/SWCNT complexes in water by measuring the ζ potential of the complexes and the turbidity of the solution were investigated. It is found that the absolute value of the ζ potential of the pLT/SWCNT complexes is as high as that of SWCNTs modified with double-stranded DNA (dsDNA) and that the complexes remain stably dispersed in the water at least for two weeks. Thermogravimetry analysis (TGA) and visualization of the surface structures of pLT/SWCNT complexes using an atomic force microscope (AFM) were also carried out. 相似文献
48.
A study was conducted to demonstrate that nanometer-thick titanium dioxide (TiO(2)) thin films could be prepared by the hydrolysis of titanium potassium oxalate using octadecylamine (ODA) Langmuir-Blodgett (LB) films as templates. The amount of TiO(2) generated in the LB film was found to be proportional to the number of deposited ODA layers, which enables precise control of the TiO(2) film thickness. After heat treatment of the LB films at 300-600°C, the photocatalytic activities of the resulting TiO(2) films were determined from the decomposition of stearic acid cast films when irradiated with UV light for different time periods. Higher photocatalytic activity was observed in TiO(2) films heat treated at lower temperatures. 相似文献
49.
Shuichi Nojima Masashi ToeiShigeo Hara Satoshi TanimotoShintaro Sasaki 《Polymer》2002,43(14):4087-4090
We have investigated the size dependence of crystallization within spherical microdomains formed in various poly(ε-caprolactone)-block-polybutadiene diblock copolymers (PCL-b-PB). The crystallinity (χ) and melting temperature (Tm) of the PCL block are considerably lower than those of PCL homopolymer, and χ decreases steadily and Tm decreases only slightly with decreasing radius of PCL spheres (R) for a series of PCL-b-PB with a same molecular weight (Mn). When PCL-b-PB is compared with the similar R but different Mn, χ is significantly different, suggesting that the sphere size is not the unique factor to control crystallization within spherical microdomains. 相似文献
50.
Steam reforming of methanol on various supported Cu catalysts was examined. Supports strongly affected catalyst activity and, among the catalysts tested, Cu catalyst supported on large-surface-area ZnAl2O4 showed the highest activity, which, to the best of our knowledge, was higher than those for the supported catalysts reported so far. For supported Cu catalysts, two species were observed. One was a dispersed Cu species having strong interaction between Cu and support, and the other was an isolated Cu species. The activity of the former species strongly depended on supports. 相似文献