从城市震灾的角度探析中小型城市公园的发展

地震及其次生灾害发生时避难疏散的经验与教训表明,中小型城市公园是重要的紧急避难场所、火灾隔离带。针对我国快速城市化进程中的城市现状,从城市震灾的角度分析了我国中小型城市公园发展中所面临的公园分布的均衡性、公园边界的开放性、公园设计的多组合策略、广泛的公众参与等相关问题,以期对我国城市管理的科学化、人性化发展有所裨益。     

Combination of silver ion and reversed-phase high-performance liquid chromatography in the fractionation of herring oil triacylglycerols

Triacylglycerols from North Atlantic herring (Clupea harengus) were separated according to the degree of unsaturation by high performance liquid chromatography (HPLC) in the silver ion mode. Each of the eleven fractions collected was then separated by reversed- phase HPLC, which in these circumstances separated the molecules according to the combined chain- lengths of the fatty acyl residues only. One hundred thirty fractions were obtained for fatty acid analysis. Almost 50% of the triacylglycerol molecules had six or more double bonds in their fatty acyl residues. Saturated-dimonoenes and disaturated- monoenes, 18.9% and 10.4%, respectively, were the most plentiful fractions of the more saturated species. Such a complex mixture of molecules was present that the most abundant subfractions from reversed- phase HPLC represented less than 5% of the total. Indeed, the largest single molecular species [16:0- 22:l- 22:6(n− 3)] represented only 2.8% of the total. These sequential analyses by complementary techniques made it possible to obtain a considerable amount of information on the composition of molecular species, but it was still not possible to identify all components.     

酶法合成长链不饱和脂肪酸酯

以固定化南极洲假丝酵母脂肪酶为催化剂合成长链不饱和脂肪酸酯。重点讨论了带水工艺、带水溶剂种类、脂肪酸碳链长度和反应温度等因素对反应的影响。结果表明,固定化南极洲假丝酵母脂肪酶对长链脂肪酸、脂肪醇的酯化反应有很好的催化效果,随脂肪酸碳链长度增加,脂肪酶的催化活力提高;有机溶剂和抽真空都可以带出反应中产生的水,溶剂带水有更好效果;相同反应时间内,反应温度60℃比50℃时有更高脂肪酸转化率;脂肪酶在50℃条件下使用30 h,酶活力与未使用前几乎完全相同。以低沸点石油醚(40~60℃)为带水溶剂,酶用量0.5%,反应温度50~60℃,反应时间6 h,可以得到酸值低于1的不饱和长碳链脂肪酸(C16~C22)油醇酯。     

Characterization of the glycerolipid composition of a high‐palmitoleic acid sunflower mutant

The glycerolipid composition of a high‐palmitoleic acid sunflower (Helianthus annuus L.) mutant accumulating up to 20% of n‐7 fatty acids was studied. This line produces oil with a complex triacylglycerol (TAG) composition, containing species that have not been previously identified in sunflower. In this regard, palmitoleic acid was esterified in an unexpected way in the three positions of the TAG molecules. The polar glycerolipid composition of the mutant was also studied, in order to identify and quantify the changes in membrane lipids imposed by the sunflower enzymatic machinery during the accumulation of the unusual n‐7 fatty acids. The high‐palmitoleic mutant accumulated important quantities of n‐7 fatty acids in the polar lipid fraction, especially in the phosphatidylcholine lipid class. However, the total polar lipid content of these lines was not affected. On the other hand, the mutations responsible for the n‐7 lipid accumulation induced an important decrease in the oil yield of the new mutant.     

Synthesis of 13(14)-hydroxy-<Emphasis Type="Italic">cis</Emphasis>-10-nonadecenyl amine hydrochloride

Compatibility between a hydrophilic nanoclay reinforcement and organophilic polymer matrix resin is achieved by ion exchange reaction substitution of intra gallery mono- or divalent cation with foreign aliphatic long-chain cation. The exchange of long-chain cation increases the organophilicity of the clay layers and provides sufficient layer separation for polymer chains to impregnate into the formation of a nanocomposite. This study demonstrates the synthesis of hydroxy functional longchain amine hydrochloride from Vernonia galamensis oil (VO). Vernonia galamensis oil, containing a naturally epoxidized long-chain TG, was transesterified under basic conditions to yield VO methyl esters (VOMe). The VOMe were reduced using lithium aluminum hydride (LAH) in hexane to obtain cis-12,13-epoxy-cis-9-octadecenol (vernanol) as the primary product. Vernanol was then converted to vernanyl mesylate, followed by reaction with potassium cyanide to obtain cis-13,14-epoxy-cis-10-nonadecenitrile (C₁₉ nitrile). The C₁₉ nitrile was reduced with LAH in diethyl ether medium and later reacted with hydrochloric acid to obtain the title product. ¹H and ¹³C NMR, FTIR, and matrixassisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) techniques were used to characterize the intermediates and the title product.     

Pseudomonas sp. lipase-catalyzed synthesis of geranyl esters by transesterification

Pseudomonas sp. lipase was immobilized by adsorption onto five supports and tested for its ability to synthesize geranyl esters by transesterification using short-chain triacylglycerols as acyl donors. Reaction mixtures were prepared in 2 mL ofn-hexane, 0.1 M geraniol, 0.03M triacylglycerol, and 200 units of lipase, and incubated at 30°C and 200 rpm for 24 h. Overall, glass beads were the best support. Geranyl acetate and caproate performed best with Duolite (77.5 and 95.3%, respectively). Geranyl butyrate and caprylate performed best with polyvinylpyrrolidone, (80.2 and 95.5%, respectively). Values for nonimmobilized enzyme also were obtained. Immobilization improved yields, with geranyl caproate exhibiting best results.     

Effect of triacylglycerol composition and structures on oxidative stability of oils from selected soybean germplasm

The oxidative stability of soybean oil triacylglycerols was studied with respect to composition and structure. Crude soybean oils of various fatty acid and triacylglycerol composition, hexane-extracted from ground beans, were chromatographed to remove non-triacylglycerol components. Purified triacylglycerols were oxidized at 60°C, in air, in the dark. The oxidative stability or resistance of the substrate to reaction with oxygen was measured by determination of peroxide value and headspace analysis of volatiles of the oxidized triacylglycerols (at less than 1% oxidation). The correlation coefficients (r) for rates of peroxide formation (r=0.85) and total headspace volatiles (r=0.87) were related positively to oxidizability. Rate of peroxide formation showed a positive correlation with average number of double bonds (r=0.81), linoleic acid (r=0.63), linolenic acid (r=0.85). Rate of peroxide formation also showed a positive correlation with linoleic acid (r=0.72) at the 2-position of the glycerol moiety. A negative correlation was observed between rate of peroxide formation and oleic acid (r=−0.82). Resistance of soybean triacylglycerols to reaction with oxygen was decreased by linolenic (r=0.87) and increased by oleic acid (r=−0.76)-containing triacylglycerols. Volatile formation was increased by increased concentration of linolenic acid at exterior glycerol carbons 1,3 and by linoleic acid at the interior carbon 2. Headspace analysis of voltiles and high-performance liquid chromatography of hydroperoxides indicated that as oxidation proceeded there was a slight decrease in the linolenic acid-derived hydroperoxides and an increase in the linoleic acid-derived hydroperoxides. The oxidative stability of soybean oil triacylclycerols with respect to composition and structure is of interest to the development of soybean varieties with oils of improved odor and flavor stability. Presented at the 81st Annual American Oil Chemists' Society Meeting, Baltimore, MD, April 18–21, 1990.     

Positional distribution of 24∶6(n−3) in triacyl-sn-glycerols from flathead flounder liver and flesh

This paper presents the positional distribution of very long-chain fatty acids, 24∶6(n−3), in triacyl-sn-glycerols (TG) of flathead flounder (Hippoglossoides dubius). Each of the liver and flesh TGs was subjected to the stereospecific analysis. The liver TGs contained 24∶6(n−3) at concentrations of 1.5, 1.2 and 1.7 mole % in thesn-1,sn-2 andsn-3 positions, respectively, and the flesh TGs had 9.0, 7.8 and 7.1 mole % in thesn-1,sn-2 andsn-3 positions, respectively. This fatty acid was distributed almost evenly among the three positions of the TGs. No preference for thesn-2 position was observed in contrast to the general tendency for the distribution of longer-chain polyunsaturated fatty acids, such as 22∶6(n−3), 22∶5(n−3) and 20∶5(n−3). There was essentially no difference in the positional distributions of the liver and flesh TGs. The results obtained in this study give new fundamental information to the investigation of very long-chain fatty acids.     

Lipopeptidic surfactants. II. Acidic and basic Nα-lauroyl-L-arginine dipeptides from pure amino acids

In this paper, the second part of a systematic study whose aim deals with the influence of the terminal amino acid side chain on the properties of Nα-lauroyl arginyl dipeptides is reported. Nα-lauroyl arginyl dipeptides that contain an acidic amino acid (glutamic acid) or a basic amino acid (lysine) as terminal amino acid have been prepared by peptide synthesis methods. These compounds have been synthesized as methyl esters (cationic surfactants) and free α-carboxylic acids (amphoteric surfactants), and their fundamental surfactant properties and antimicrobial activity have been evaluated. The properties of these compounds have been compared to the properties of the cationic monomer derivative methyl ester of Nα-lauroyl arginine and of the amphoteric monomer derivative Nα-lauroyl arginine reported earlier. The compounds are soluble in water and show surface activity, although in the case of the amphoteric Nα-lauroyl arginyl dipeptide containing glutamic acid these two properties depend on the solution pH. The cationic Nα-lauroyl arginyl dipeptides are antimicrobial agents. However, only the amphoteric compound containing lysine may be considered antimicrobial.     

Characterization of wax sediments in refined canola oils

Turbidity components in refined canola oils were collected by filtration at 4 and 20°C. Major components (thin-layer chromatography) at both temperatures were wax esters (WE), hydrocarbons (HC) and triacylglycerols (TG) while free fatty acids (FFA) and fatty alcohols (FAL) were found in minor amounts at 4°C. WE had carbon numbers of 40 to 56 (made up of combinations of C16 to C30 alcohols and C16 to C28 fatty acids). HC were mostly C29 and C31 with lesser amounts of C24, C28 and C32. TG, compared to the corresponding liquid oil, still contained C18:1 as the major component, but had less C18:2 and particularly less C18:3 and at least two times higher levels of saturated fatty acids. The FFA were mainly long-chain C22:0, C24:0 and C20:0 (in order of amount). FAL were mainly long-chain C26:0, C28:0 and C30:0 but ranged from C16:0 to C32:0. Presented in part at the 1991 American Oil Chemists’ Society Annual Meeting and Exposition, Chicago, May 15. Received Outstanding Paper Award 1991, Chicago (82nd) Annual Meeting.