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61.
Let be the graph of a continuous map of the unit sphere of into , and the polynomially convex hull of . Several examples of for are given, which have different properties from the known ones for .
62.
63.
Yoshiaki Nakamoto Isao Karube Seikichi Terawaki Shuichi Suzuki 《Applied biochemistry and biotechnology》1976,1(2):143-149
Collagen fibrils were modified with β-l-[3,3-dimethyl-6′-nitrospiro-(indoline-2,2′-2H-benzopyran)] propionic anhydride. The spiropyran collagen membrane showed reverse photochromism. Lactate dehydrogenase (LDH, E.C. 1.1.1.27) was entrapped in the spiropyran collagen membrane. The activity of the LDH-spiropyran collagen membrane decreased under visible-light irradiation, and then increased again after incubation in the dark. The optimum pH of the LDH-spiropyran collagen membrane was displaced toward lower pH values under visible-light irradiation. The activity change of the LDH-spiropyran collagen membrane under visible-light irradiation depended on the LDH content. 相似文献
64.
Kaihara S Osanai Y Nishikawa K Toshima K Doi Y Matsumura S 《Macromolecular bioscience》2005,5(7):644-652
The enzymatic transformation into an oligomer was carried out with the objective of developing the chemical recycling of bacterial polyesters. Poly(R-3-hydroxyalkanoate)s (PHAs), such as poly[(R-3-hydroxybutyrate)-co-12%(R-3-hydroxyhexanoate)] and poly[(R-3-hydroxybutyrate)-co-12%(R-3-hydroxyvalerate)], were degraded by granulated Candida antarctica lipase B immobilized on hydrophilic silica (lipase GCA) in a diluted organic solvent at 70 degrees C. The degradation products were cyclic oligomers having a molecular weight of a few hundreds. The obtained cyclic oligomer was readily repolymerized by the same lipase (lipase GCA) to produce the corresponding polyester in a concentrated solution. The cyclic oligomer was copolymerized with epsilon-caprolactone using lipase to produce the corresponding terpolymers having an Mw of 21,000. This is the first example of the enzymatic chemical recycling of bacterial PHAs using lipase. Poly(R-3-hydroxybutyrate) [P(3HB)] was also degraded into the linear-type R-3HB monomer to trimer by P(3HB)-depolymerase (PHBDP) in phosphate buffer at 37 degrees C. The degradation using PHBDP required a longer reaction time compared with the lipase-catalyzed degradation in organic solvent. The monomer composition of the oligomer depended on the origin of the PHBDP. The R-3HB monomer was predominately produced by PHBDP from Pseudomonas stutzeri, while the R-3HB dimer was produced by PHBDP from Alcaligenes faecalis T1. Repolymerization of these oligomers by lipase in concentrated organic solvent produced a relatively low-molecular-weight P(3HB) (e.g., Mw=2,000). Degradation of P(3HB) by lipase in organic solvent into repolymerizable cyclic oligomer and degradation of P(3HB) by PHBDP in buffer into hydroxy acid type R-3HB dimer. 相似文献
65.
Yusuke Arai Tetsuji Yano Shuichi Shibata 《Journal of Sol-Gel Science and Technology》2004,32(1-3):189-194
Microspheres of refractive index of nD > 2.0 have been investigated. The organic-inorganic hybrid microspheres of nD = 1.72 were prepared by the vibrating orifice technique using titanium-tetra-n-butoxide (TTBu) and diphenyldimethoxysilane (DPhDMS). For lasing demonstration, Eu3+-doped microspheres were prepared using europium (III) thenoyltrifluoroacetonate [Eu(TTFA)3] as the dopant. The particles have good spherical shape, smooth surface and high optical transparency. The diameters of the particles could be controlled to within 0.1 m. Subsequent heating of the microspheres at 550°C under oxygen atmosphere resulted in an increase in the refractive index up to nD = 2.6 with retention of the spherical shape. Resonant emission was confirmed from Eu3 +-doped microspheres after heating at 400–550°C, by pumping with the 514.5 nm line of a CW- Ar+laser. 相似文献
66.
Electric polarization in insulators is represented by the transferred charge through a shift of the Bloch wave functions induced by an adiabatic change of external parameters Q-->. It is found that this covalent/quantum contribution is determined nonlocally by the topological structure in the Q--> space. The condition for the charge pumping for a cyclic change of Q--> is also obtained. Applications of this picture to various organic ferroelectrics and BaTiO3 are discussed. 相似文献
67.
Kato S Matsumoto T Ishi-i T Thiemann T Shigeiwa M Gorohmaru H Maeda S Yamashita Y Mataka S 《Chemical communications (Cambridge, England)》2004,(20):2342-2343
Novel donor-pi-bridge-acceptor-pi-bridge-donor (D-pi-A-pi-D) type 2,1,3-benzothiadiazole fluorescent dyes connected to the N,N-diarylamino terminus via various type pi-conjugate spacers exhibits large two-photon absorption cross-sections and high fluorescent quantum yields in orange-red color. 相似文献
68.
Chiba JY Tanaka K Ohshiro Y Miyake R Hiraoka S Shiro M Shionoya M 《The Journal of organic chemistry》2003,68(2):331-338
This paper describes a convenient synthetic procedure for nucleoside mimics, 1-6, in which the 3',5'-hydroxy groups of natural 2'-deoxythymidine or 2'-deoxyadenosine are replaced by thiol, amine, or alkylthiol groups. Such nucleosides would be built up into a single DNA strand with cooperative participation of metal coordination, where internucleoside linkages are replaced by metal complexation motifs. The X-ray crystal structure and complexation behaviors of 3',5'-dithiothymidine, 1, with Au(I) are also reported. 相似文献
69.
The spatial propagation of synchronized activity in cortical slice cultures was characterized by multi-site extracellular recording. Spontaneous activity was studied in normal culture medium, and in bicuculline- or kainic acid-containing media. A common feature in all these conditions was that activity was generated first in superficial layers (i.e., layer I/II) before spreading over the whole area of the slice. In culture medium or bicuculline-containing medium, the initiation site of the activity was not constant and showed a large variety of patterns of horizontal propagation. Kainic acid induced epileptiform activity, consisting of intense initial bursts followed by repetitive after-discharges. Though the patterns of spatial propagation of the bursts were variable as in the other conditions, the after-discharges followed a constant path. Cross-correlation analysis indicated that the network moved in a graded fashion to a steady state during the sequence of after-discharges. 相似文献
70.
A catalytic immuno-reactor for the determination of human serum albumin (HSA) was constructed by using immobilized antibody and an amperometric detector. A sandwich assay with hemin-labeled antibody to catalyze the decomposition of hydrogen peroxide was used, the catalytic activity of the hemin-antibody conjugate being determined by measuring the decrease in hydrogen peroxide concentration. The reaction of hemin-labeled antibody with antigen was complete within 30 min and the current decrease was correlated with the HSA concentration. The relative standard deviation was about 9% at an HSA concentration of 1 mg ml?1. 相似文献