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排序方式: 共有92条查询结果,搜索用时 31 毫秒
41.
Mayuko?Takasu Toshifumi?Shiroya Kimiya?Takeshita Munehiro?Sakamoto Haruma?KawaguchiEmail author 《Colloid and polymer science》2004,282(7):740-746
Polymer particles containing oil-soluble dyes (colored latex) were prepared by miniemulsion polymerization. The dye preservation properties of colored latex loaded with different types of dye were studied; preservation depended on the rate of dye diffusion and thus on the size of the dye molecules and the hardness of the polymer matrix in the latex particles. Hindered amine stabilizers (HAS) were used to improve the photostability of colored latex. The effect of HAS in colored latex was investigated both as an additive and as a comonomer. The photostability of latex particles containing a simple mixture of dye and HAS was improved with increasing HAS content up to 20% in particles. In the case of colored latex particles combined with HAS by a covalent bond, the optimal amount of HAS for photostability improvement was between 8 and 20%. 相似文献
42.
Nojima H Takeda-Shitaka M Kurihara Y Adachi M Yoneda S Kamiya K Umeyama H 《Chemical & pharmaceutical bulletin》2002,50(9):1209-1214
Class I major histocompatibility complex (MHC) binds antigen peptides with various sequences. We performed a normal mode analysis of HLA-A2 MHC that binds three peptides with different affinity. HLA-A2 MHC has a peptide-binding groove composed of two alpha-helices (residue 49-84, residue 140-179). Some residues in the center of the groove showed an increase in fluctuations and some residue pairs between two helix groups showed a negative change in correlations by removing the antigen peptide. The extent of the fluctuation and correlation changes correlated well with the experimental ranking of the three peptides in binding affinity. Some definite anti-correlative motions were found between two helix groups in low frequency modes (<50 cm(-1)) by removing the antigen peptide. We propose that the above anti-correlative motions play an important role to bind the antigen peptide, especially in obtaining a "dynamic fit." 相似文献
43.
Hara M Samori S Cai X Tojo S Arai T Momotake A Hayakawa J Uda M Kawai K Endo M Fujitsuka M Majima T 《The journal of physical chemistry. B》2005,109(2):973-976
Formation and decay processes of stilbene core radical cation (ST*+) during the photoinduced electron transfer have been studied for a series of stilbene bearing benzyl ether-type dendrons (D). ST*+ and the radical cation of peripheral dendron (D*+) were generated by intermolecular hole transfer from biphenyl radical cation, which was generated from photoinduced electron transfer from biphenyl to the singlet-excited 9,10-dicyanoanthracene in a mixture of acetonitrile and 1,2-dichloroethane (3:1). An intramolecular dimer radical cation of benzyl groups at the terminal of stilbene dendrimer was indicated as a hole trapping site. Subsequent hole transfer from the trapping site to the core ST generated ST*+. The shielding effects of D depending on the dendrimer generation on the growth and decay of ST*+ were observed. It was revealed for the first time that D acts as the hole trapping site and the hole conductor on the way of the exothermic hole transfer from the terminal of D to the central core ST. We also found that D inhibits the charge recombination with 9,10-dicyanoanthracene radical anion because of the steric hindrance. 相似文献
44.
M. Takehisa H. Shintani M. Sekiguchi T. Koshikawa T. Oonishi M. Tsuge K. Sou Y. Yamase S. Kinoshita H. Tsukamoto T. Endo K. Yashima M. Nagai K. Ishigaki Y. Sato J. L. Whitby 《Radiation Physics and Chemistry》1998,52(1-6):21-27
An extensive study of the radiation resistance of microbial species constituting the bioburden of a number of different medical devices obtained from Japanese medical device manufacturers has been carried out. A standard protocol for determining radiation resistance was used and validated at the fourteen centres involved in the study. Individual microbial isolates from the bioburden obtained from seven different devices manufactured in these centres were studied. A total of 3742 unselected isolates were obtained, of which 197 failed to survive long enough for subsequent radiation resistance studies. The remainder were subjected to an initial screen test to identify those organisms that were sensitive to the lethal effects of radiation with a D10 of < 1.5kGy. The 465 isolates that survived the screen doses were then tested for survival in an incremental series of radiation doses using methods similar to those of Whitby (1979) and Yan and Tallentire(1995). The isolates from “dry” devices were more resistant than those obtained from the one water filled (“wet”) device studied. The overall distribution of radiation resistance among the isolates was considered to be similar to that forming the “Standard Distribution of Resistance” (SDR) included in the ISO International Standard 11137 “Sterilization of Health Care Products — Requirements for validation and routine control — Radiation sterilization”. 相似文献
45.
Kraus A Hanbücken M Koshikawa T Neddermeyer H 《Analytical and bioanalytical chemistry》2002,374(4):688-694
An overview is given on the use of scanning tunneling microscopy (STM) for investigation of the adsorption of hydrogen on Si(111)7 x 7 both at room temperature and at elevated temperature to finally obtain a hydrogen-saturated surface of Si(111). The initial stages are characterized by high reactivity of Si adatoms of the 7 x 7 structure. After adsorption of hydrogen on the more reactive sites in the beginning of the adsorption experiments a regular pattern, which is different for room and elevated temperature, is observed for the less reactive sites. In agreement with previous work, local 1 x 1 periodicity of the rest atom layer and the presence of di- and trihydride clusters is observed for hydrogen-saturated surface. STM has also been used to characterize surfaces from which the hydrogen atoms have been removed by thermal desorption. Finally, tip-induced desorption by large positive sample-bias voltages and by increasing the tunneling current will be described. 相似文献
46.
S. Adachi Y. Ogata N. Koshikawa S. Matsumoto K. Kinoshita I. Yoshizaki T. Tsuru H. Miyata M. Takayanagi S. Yoda 《Journal of Crystal Growth》2005,280(3-4):372-377
It is indispensable to estimate a diffusion coefficient in a solution zone in order to grow a homogeneous crystal by using the traveling liquidus-zone (TLZ) method. To estimate the diffusion coefficient of Ge in the SiGe solution zone, result of a two-dimensional numerical simulation is compared with an experimental result. From the comparison, the diffusion coefficient is estimated to be 9.5×10−5 cm2/s. By using this coefficient, a sample translation rate for obtaining a homogeneous SiGe crystal is determined. By translating samples with appropriate rates, homogeneous Si0.5Ge0.5 crystals are successfully grown. The typical Ge composition is 0.496±0.006 for more than 13 mm long. The experimental result shows the homogeneity of ±1.2% in the mole fraction. This deviation corresponds to the variation of less than ±0.03% in the lattice constant. Since this variation is negligibly small, the homogeneity is excellent. Thus it is found that the TLZ method is the universal growth technique, which is applicable to the crystal growth of not only the III–V compounds but also the IV–IV compounds. 相似文献
47.
Kotatha Ditpon Morishima Kenta Uchida Satoshi Ogino Mayuko Ishikawa Masashi Furuike Tetsuya Tamura Hiroshi 《Research on Chemical Intermediates》2018,44(8):4971-4987
Research on Chemical Intermediates - A novel gel electrolyte has been prepared using bacterial cellulose (BC) coated with chitosan (CTS) and alginate (Alg) layers, which contain... 相似文献
48.
The growth of Cu on the clean and hydrogen-terminated Si(1 1 1) surfaces is studied in situ by low-energy electron microscopy (LEEM). The dependence of the growth of the “5×5” layer on the clean Si(1 1 1) 7×7 surface upon the deposition temperature is investigated by combining LEEM with LEED. After completion of the “5×5” layer not only the regular-shaped three-dimensional islands reported before are observed but also irregular shaped more two-dimensional islands. On the hydrogen-terminated Si(1 1 1) surface the formation of the “5×5” structure is suppressed and nano-scale islands form preferentially at the step edges and domain boundaries. This is attributed to the enhancement of the surface migration of Cu atoms by the elimination of the surface dangling bonds. 相似文献
49.
Dr. Julien Leclaire Dr. Messaoud Mazari Yuan Zhang Dr. Colin Bonduelle Dr. Olivier Thillaye du Boullay Prof. Blanca Martin‐Vaca Dr. Didier Bourissou Dr. Innocenzo De Riggi Dr. Rémy Fortrie Prof. Frédéric Fotiadu Prof. Gérard Buono Rémi Plamont Dr. Yoshihiro Kikkawa Mayuko Takahashi Dr. Masatoshi Kanesato Dr. Michel Giorgi Anita Chan Kam Shun Prof. Dr. Christian Roussel Prof. Dr. Teodor Silviu Balaban 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(34):11101-11101
50.
Mori M Ito T Teshima S Hatta H Fujita S Nishimoto S 《The journal of physical chemistry. B》2006,110(24):12198-12204
Steady-state gamma-radiolysis, pulse radiolysis, and cyclic voltammetry have been performed to identify the mechanism by which N(1)-C(5')-linked homodimer hydrates [1-(6'-hydroxy-5',6'-dihydrothymin-5'-yl)thymine (2a) and [1-(5'-fluoro-6'-hydroxy-5',6'-dihydrouracil-5'-yl)-5-fluorouracil (2b)], N(1)-C(6')-linked dimer hydrate [1-(5'-hydroxy-5',6'-dihydrothymin-6'-yl)thymine (3a)], and N(1)-C(5')-linked heterodimer hydrate [1-(6'-hydroxy-5',6'-dihydrothymin-5'-yl)-5-fluorouracil (2ba)] undergo radiolytic reductive splitting to regenerate the parent monomers in anoxic aqueous solution. Radiolytic reductions of the thymine homodimer hydrates 2a and 3a by hydrated electrons (e(aq)-) regenerated the parent thymine (1a) almost quantitatively, while the 5-fluorouracil homodimer hydrates cis-2b and trans-2b afforded 1-(uracil-5'-yl)-5-fluorouracil efficiently along with a small amount of the parent 5-fluorouracil (1b). In contrast to 2b, the heterodimer hydrate analogue 2ba with noneliminating 5'-methyl substituent releases 5-fluorouracil 1b almost quantitatively in the radiolytic reduction. The pulse radiolysis studies suggested that the electron adducts are produced primarily at the thymine and 5-fluorouracil structural unit in the dimer hydrates 2a,b, respectively, in which the resulting dimer hydrate radical anion of 2b (2b*-) was more stable than that of 2a (2a*-). As characterized by pulse radiolysis and cyclic voltammetry, the 5-fluorouracil homodimer hydrate 2b bearing F-substituent at C(5') undergoes one-electron reduction to eliminate exclusively fluoride ion along with the formation of dimer hydrate C(5') radical (2b(-F)*) with oxidizing property. The formation of a possible dimer hydrate radical intermediate 2b(-F)* was also supported by the effect of amines as the reducing additives on the yields of 1b and 4b in the radiolytic reduction of 2b. 相似文献