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51.
Polyester elastomers were prepared by block copolymerization of dimethyl terephthalate (DMT), butanediol (BDO), and polytetramethylene glycol (PTMG). Polyester from DMT and butanediol forms a high-melting hard segment in block copolyester to prevent undue chain slippage when fibers are stretched. High elongation was provided by soft segment which consisted of condensation product from DMT and PTMG. Experiments were carried out to determine the effect of composition variables on the properties of these elastomers, such as glass transition temperature, elongation at break, tenacity, and elastic recovery. The study on molecular characteristics of the elastic polyester showed that a leather-like region exists between glassy and rubbery regions. These elastomers were melt-spun to give elastic fibers which are competitive with commercially available Spandex-type fibers. 相似文献
52.
Improved separation of alpha chains of collagen type I (alpha 1 [I]2 alpha 2[I]), type III(alpha 1[III]3), and type V (alpha 1[V]alpha 3[V])was achieved by noninterrupted sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a negatively charged reducer, thioglycolic acid. The thioglycolic acid, added to the running buffer of the cathodic reservoir, in the middle of electrophoresis quickly migrated in the gel anode, reducing interchain disulfide linkages in collagen type III and dissociating it into its alpha chain monomer, alpha 1[III], without an interruption of electrophoresis. The alpha chain, alpha 1[III], migrated more slowly than the alpha 1 [I] and alpha 2[I] chains of collagen type I, resulting in an excellent separation of alpha 1[III] from alpha 1[I]. The mobility of alpha 1[III] could be controlled by varying the time of thioglycolic acid addition to the running buffer. This enabled us not only to separate alpha 1[III] from alpha 1[I] and alpha 1[V], but also to precisely quantitate these alpha chains, even at low protein loading of mixed samples. 相似文献
53.
Ohsaka T Tian Y Shioda M Kasahara S Okajima T 《Chemical communications (Cambridge, England)》2002,(9):990-991
A superoxide dismutase (SOD)-modified electrode, in which SOD is oriented on the gold electrode via a self-assembled monolayer of cysteine so as to allow its direct electrode reaction, possesses a bi-directional electrocatalysis for both the oxidation of superoxide ion (O2-) to O2 and the reduction of O2- to H2O2 and functions as a third generation O2- biosensor. 相似文献
54.
[reaction: see text] Radical cascade reaction with various 1,4-dienes and 1,4-enynes using dimethyl 2-(iodomethyl)cyclopropane-1,1-dicarboxylate as a homoallyl radical precursor smoothly proceeds through an iodine atom transfer mechanism to give functionalized bicyclo[3.3.0]octane derivatives in good yields. 相似文献
55.
Visible photoluminescence (PL) of nanocrystalline silicon (nc-Si) embedded in single crystal CaF2 formed on Si(1 1 1) has been studied and the influence of ex situ rapid thermal annealing (RTA) on the surface morphology and PL spectra has been studied. It has been found that the PL intensity and uniformity was improved by RTA with appropriate temperature and short annealing time. 相似文献
56.
Hiroshi Tanaka Takeo Yoshioka Yasutaka Shimauchi Akihiro Yoshimoto Tomoyuki Ishikura Hiroshi Naganawa Tomio Takeuchi Hamao Umezawa 《Tetrahedron letters》1984,25(31):3351-3354
The tricyclic quinone 8 was successfully synthesized from naphthazalin, and the total synthesis of (±)-2-hydroxyaklavinone via 8 was accomplished in an overall yield of about 18% through the regio-controlled route. 相似文献
57.
Munetaka Nakata Masaaki Sugie Harutoshi Takeo Chi Matsumura Tsutomu Fukuyama Kozo Kuchitsu 《Journal of Molecular Spectroscopy》1981,86(1):241-249
The microwave spectra of four isotopic species of dichlorine monoxide (OCl2) have been observed, and the rotational constants have been obtained. The rm structure for each isotopic species has been determined by Watson's method. The equilibrium structure has been estimated by taking proper averages of rm structures to be and ∠eClOCl = 110.886(6)°. The general applicability and the merit of the present method for estimating the equilibrium structure are pointed out. 相似文献
58.
59.
Both abilities of germination of spores formed after UV irradiation and of growth of amoeboid cells emerged from the spores were studied on two kinds of Dictyostelium discoideum strains, NC-4 and ys-13.
An inhibition of germination was observed on the spores of ys -13 when formed after UV irradiation, while no inhibition was detected on the ability of germination of spores of NC-4. The amoeboid cells of ys -13 emerged from the spores showed a heavy delay of growth, although no delay of growth was detected even on the amoeboid cells of NC-4 emerged from the spores formed after UV irradiation. The strain of NC-4 must repair UV lesions fully before spore formation, while the spores of ys-13 must keep some UV lesions unrepaired and send them to the next generation of amoeboid cells. The characters of UV lesion inheritable through the spores to the next amoeboid cells in ys-13 were discussed. 相似文献
An inhibition of germination was observed on the spores of ys -13 when formed after UV irradiation, while no inhibition was detected on the ability of germination of spores of NC-4. The amoeboid cells of ys -13 emerged from the spores showed a heavy delay of growth, although no delay of growth was detected even on the amoeboid cells of NC-4 emerged from the spores formed after UV irradiation. The strain of NC-4 must repair UV lesions fully before spore formation, while the spores of ys-13 must keep some UV lesions unrepaired and send them to the next generation of amoeboid cells. The characters of UV lesion inheritable through the spores to the next amoeboid cells in ys-13 were discussed. 相似文献
60.
Takeo Ojika 《Journal of Mathematical Analysis and Applications》1980,73(1):192-203
A natural interpretation of “maj” and “inv” q-counting of multiset permutations in terms of walks on a lattice with multilane highways is presented. This is applied to give a short combinatorial proof of two theorems of MacMahon and to rederive a recent result of Gessel. 相似文献