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991.
Studies have been carried out on electron beam induced polymerization of LB films of saturated and unsaturated long chain aliphatic acids, in an attempt to obtain information about the dose dependence of conversion in relation to molecular arrangement. The results indicate that polymerization of unsaturated aliphatic acid LB films occurred when irradiation was carried out in a nitrogen atmosphere and that the LB films of a disordered state are more sensitive to radiation than tightly packed LB films. 相似文献
992.
Network formation of gelatin gel is known to consist of three-dimensionally cross-linked triple helices among polypeptide
chains. The effects of added low molecular weight mono-ols, diols and polyols on the higher-order structure formation of gelatin
chains were investigated using the following measurements: melting temperature, viscoelasticity and spin-lattice relaxation
time (T
1) of H17
2O of gels, and circular dichroism spectra of diluted gelatin solutions. Furthermore, hydration behaviors of these hydroxy
compounds were evaluated from the dynamic hydration numbers (n
DHN) derived from T
1 of H17
2O in the solutions. It was found that network structures of gelatin gels containing hydoxy compounds were influenced by the
number and position of hydroxyl groups as well as the number of carbon atoms of these coexisting compounds. The effect of
hydroxyl groups of hydroxy compounds was considered to stabilize the helices among gelatin chains. Especially, the addition
of polyols with large number of hydroxyl groups increased the number of cross-linking junctions in the gel networks, which
consist of the aggregation among the helices. On the contrary, the effect of carbon atoms of hydroxy compounds is to disturb
the formation of the helices and the aggregation among the helices.
Received: 18 April 1996/Accepted: 23 July 1996 相似文献
993.
Electrochemical fluorination (ECF) of the ester derivatives of oxolane-2-yl-carboxylic acid (1), oxolane-2-yl-methanol (2) and oxane-2-yl-methanol (3) were investigated. Perfluoro(oxolane-2-yl-carbonylfluoride) (4) was obtained from derivatives of 1 and 2, and perfluoro(oxane-2-yl-carbonylfluoride) (5) was obtained from derivatives of 3 as the desired compounds, respectively. From the ECF of acetates of 2 and 3, perfluorospiroethers having a dioxolane ring were also obtained as the cyclization product in low yield together with the desired perfluoroacid fluoride (4 and 5). The structure of these perfluorospiroethers was confirmed by analyzing the chlorinated products, which were obtained by the reaction with AlCl3. 相似文献
994.
Toshio Goto Tadao Kondo Hirotoshi Tamura Hiroyuki Imagawa Aya Iino Kosaku Takeda 《Tetrahedron letters》1982,23(36):3695-3698
Structure of gentiodelphin is determined to be 5, 3′-d8-O-(6-O--caffeoylβ-D-glucosyl)-3-O-(β-D-glucosyl)delphinidin. The anthocyanin is stable in dilute neutral aqueous solution. This stabilization may be caused from intramoleculaur hydrophobic interactions among the aromatic nuclei; the anthocyanidin being sandwiched win between two caffeic acids. 相似文献
995.
Structure of cinerarin is determined to be 3-0-(6-0-malonyl-β-D-glucopyranosyl)-7-0-(6-0-(4-0-(6-0-caffeyl-β-D-glucopyranosyl)caffeyl)-β-D-glucopyranosyl)-3′-0-(6-0-caffeyl-β-D-glucopyranosyl)delphinidin. 相似文献
996.
Screening tests are described for the development of chemiluminescence systems (oxidizing systems) capable of detecting biological organic compounds. The light emission depends strongly on the oxidizing systems employed. Acidic permanganate system gives rise to light emission for many compounds, including catechols, catecholamines, triphenols and indoles. The following oxidizing systems led specifically to chemiluminescence for hydroquinone, adrenaline or phenylpyruvic acid: 10?1 M thiosulphate with 10?1 M sodium hydroxide and 10?4 M Ag (I), 0.3 % hydrogen peroxide with 10?3 M sodium hydroxide/50% acetonitrile and 10?4 M Fe (II), and 0.3% hydrogen peroxide with 10?2 M sodium hydroxide/10?2 M didodecyldimethylammonium bromide and 10?4 M Co(II), respectively. 相似文献
997.
Y Yamauchi T Tomita M Senda A Hirai T Terano Y Tamura S Yoshida 《Journal of chromatography. A》1986,357(1):199-205
Arachidonic acid (AA) metabolites produced by washed human platelets and rat macrophages were analyzed by high-performance liquid chromatography (HPLC) using a pre-column derivatization method. The reagent, 9-anthryldiazomethane, used in this study and AA metabolites derivatized by the reagent were purified by gel permeation chromatography (PG-pak C column), prior to normal-phase HPLC analysis. A sample containing eleven derivatives (12-, 15- and 5-hydroxyeicosatetetraenoic acid, 12-L-heptadecatrienoic acid, leukotriene B4, prostaglandins B2, D2, E2 and F2 alpha, thromboxane B2 and 6-keto-prostaglandin F1 alpha) was separated on a normal-phase column (PG-pak B); the detection limit is better than 100 pg for all components. 相似文献
998.
Yasuhiro Kamitori Masaru Hojo Ryōichi Masuda Tatsuro Inoue Tatsuo Izumi 《Tetrahedron letters》1982,23(44):4585-4588
Lithium aluminum hydride, in the presence of a small amount of silica gel, has been found to be a versatile and highly selective reagent for reduction of various ketoesters to the corresponding hydroxyesters in fair yields. 相似文献
999.
Suzuki Y Sazaki G Matsui T Nakajima K Tamura K 《The journal of physical chemistry. B》2005,109(8):3222-3226
The growth and dissolution rates of glucose isomerase crystals ({1 0 1} face) were measured in situ at 0.1 and 100 MPa. From these data, we determined that the solubilities at 25 degrees C were C(e) = 3.1 +/- 0.9 and 2.6 +/- 0.5 mg mL(-1) at 0.1 and 100 MPa, respectively. At the same supersaturation of sigma = 2.5 (sigma identical with ln(C/C(e)), C = the concentration of glucose isomerase, C(e) = the solubility) and temperature (T = 25 degrees C), the growth rate under 100 MPa was 7.6 times larger than that under 0.1 MPa. This result shows, for the first time, a kinetic acceleration of the growth rates of protein crystals with increasing pressure. The growth rates vs sigma data fitted well with a two-dimensional nucleation growth model of a polynucleation type. The fitting results indicate that the acceleration is mainly due to the decrease in the molecular surface energy of the glucose isomerase crystal with pressure. 相似文献
1000.
The reduction of tetrachloroaurate or potassium tetrachloropalladate with sodium borohydride in the presence of optically active 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl [BINAP] gave the chiral (S)- or (R)-BINAP-stabilized gold or palladium nanoparticles which showed the small core (1.7 nm for BINAP-Au and 2.0 nm for BINAP-Pd) with narrow size distribution and remarkably high stability. Asymmetric hydrosilylation of styrene with trichlorosilane in the presence of chiral BINAP-Pd nanoparticles afforded an optically active 1-phenyl-1-trichlorosilylethane which was converted into an optically active 1-phenylethanol (95% enantiomeric excess) by oxidative cleavage of the carbon-silicon bond. 相似文献