The protected octadecapeptide corresponding to positions 26 through 43 of porcine gastric inhibitory polypeptide was synthesized by a conventional method. In this deprotected peptide, any significant inhibitory effect against the gastric acid secretion stimulated by histamine hydrochloride was not noted in heidenhein pouch dogs.
The oxidative stability of unsaturated lipids generally decreases with increase in unsaturation. Highly unsaturated fatty acids such as docosahexaenoic acid (22 6 n-3, DHA) and icosapentaenoic acid (20 5 n-3, EPA) are thus more easily oxidized in air, with consequent decrease in food quality. Few reports on the autoxidative behavior of fatty acids in different molecular forms have appeared to date. The autoxidative behavior of fatty acids (FA), fatty acid methylesters (FAME), triacylglycerols (TG) and phospholipids (PL), all possessing essentially the same fatty acid compositions, was thus examined in this study at 30°C in the dark and the results were compared. The study was made with and then without antioxidant tocopherols (Toc).PL was the most oxidatively stable, followed by TG>FAME>FA, with or without Toc under the autoxidation conditions used. PL hydroperoxide decomposed into carbonyl compounds more quickly than any other lipid. Autoxidative behavior of complex lipid such as PL was different from simple lipids like FA, FAME and TG.
The cationic polymerization of 3-methyl-3-(phthalimidomethyl)oxetane (1) afforded two kinds of polymers. One was a polyacetal, i.e., poly{oxy(8,9-benzo-4-methyl-7-oxo-2,6-oxazabicyclo[4.3]nona-8-ene-1,4-diyl)methylene} (3), produced at 50 °C and below, and the other was a polyether, i.e., poly[oxy(2-methyl-2-phthalimidomethyltrimethylene)] (4), produced at 80 °C and above. This new polymerization with the two ring-opening courses was accompanied by the monomer-isomerization process of 1 to give 5,6-benzo-1-methyl-8,11,3-dioxazatricyclo[5.2.2.03,7]undeca-5-en-4-one (2). The cyclic acetal 2, therefore, functioned as the real monomer, and either single or double ring-opening polymerization took place to give 3 or 4, respectively, depending on the reaction temperature. The strain of 2 for ring-opening is discussed on the basis of the result of X-ray structure analysis. The single ring-opening process of 2 was an equilibrium polymerization having the standard enthalpy and entropy changes in dichloromethane equal to −15.8 kJ mol-1 and −46.0 J mol-1 K-1, respectively, and the ceiling temperature (Tc) equal to 70.1 °C for 1 mol L-1 solution. The critical temperature, where the structure of the product polymer changed, was related to a Tc calculated for the conditions employed (59.1 °C for polymerization in 0.83 mol L-1 dichloromethane solution). Therefore, 3 was successfully transformed to 4 with a thermal latent catalyst at a higher temperature than the Tc through the ring-closure depolymerization of 3 to 2 followed by the repolymerization of 2 in the double ring-opening manner. When 1 was polymerized in a temperature step-down mode, a block copolymer with the 3-4 sequence was prepared from the single monomer. Moreover, 1 was copolymerized with a nonisomerizable oxetane, accompanying the monomer isomerization of 1.
Methods for the qualitative analysis and determination of antimicrobial agents in fabrics are described. At present, antimicrobial agents mainly used are 2, 4, 4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300), 3-(trimethoxysilyl) propyldimethyloctadecyl ammonium chloride (DC5700) and thiabendazole (TBZ). The procedure of qualitative analysis is as follows : (1) DC-5700 in fabrics is checked by the adsorption of bromophenol blue (BPB) on the strips packed in column. (2) Irgasan DP300 eluted with ether from fabrics is detected by Gibbs reagent on silica gel thin layer chromatography (TLC). (3) TBZ is eluted with methanol from the fabrics after the ether-elution and detected by UV 254 nm after spraying sulfuric acid on silica gel TLC. DC-5700 is determined from the amount of 1-octadecene, formed in Hofmann degradation, measured by gas-liquid chromatography (GLC). The determination of Irgasan DP300 in fabrics is carried out by high performance liquid chromatography (HPLC) on the acidic fraction of extract with methanol : acetic acid (9 : 1) under reflux and TBZ is determined by GLC on the alkaline fraction of the abovementioned extract. By using the qualitative and quantitative system, Irgasan DP300, DC-5700 and TBZ were detected in 12, 4 and 2 samples, respectively, of 23 commercial fabrics treated with antimicrobial agents.
The weight of testis of the guinea fowl under 12L:12D and 6L: 18D was found to be greater at 30 weeks of age than that under 18L: 6D, although smaller at 10 and 20 weeks of age. The age at first egg-laying under 12L: 12D was 283 days which was the longest among the groups. It was about 157 days and about 129 days and 129 days longer under 12L: 12D and 6L: 18D than that under 18L: 6D or 14L: 10D, respectively. The weight of the first egg and of its yolk was greater in hens under 12L: 12D or 6L: 18D than those under 18L: 6D or 14L: 10D. The greater testicular growth and the remarkable delay in the onset of egg-laying in hens under 12L: 12D and 6L: 18D may be characteristic of the guinea fowl.
Taurine showed a strong hypocholestrolemic effect in hypercholesterolemic WKY and SHRSP induced by the feeding of a high-fat and high-cholesterol diet. The hypocholesterolemic effect, which was more remarkable in SHRSP than in WKY, was mainly due to suppression of the marked increase of cholesterol, apo B and apo E in the VLDL and IDL fractions, and to prevention of cholesterol accumulation in the liver. In addition, a recovery in the HDL fraction of SHRSP, associated with increases of cholesterol and apo A-I, was observed after taurine treatment, while, in the HDL fraction of WKY, the decreased apo E content was reduced further and no effective change was observed.
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