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Isomeric Monoenoic Acids in Vegetable Oils In the scope of systematic studies the fatty acids of oils from seed and fruits of 38 plants are investigated for presence of isomeric monoenoic acids with 16, 18 and 20 C-atoms. All analyzed oils contain between 2 and 4 hexadecenoic, octadecenoic and icosenoic acids with different position of the double bound. Vaccenic acid, the cis-11-octadecenoic acid, is always found in low quantities. Its share depends within certain limits on the content of the oils of cis-9-hexadecenoic acid, the so-called palmitoleic acid. Petroselinic acid, cis-6-octadecenoic acid, is found in apiaceae oils and also in the seed oil of some other plant families. Besides, 14 of the investigated oils contain low quantities of ω5-monoenoic acids. 相似文献
83.
Linear polymers, particularly polyesters, and crosslinked epoxide systems were studied to determine the relationship between glass transition, Tg, and cohesive energy, Ecoh, which was calculated from incremental values as described by Fedors. In the case of thermoplastics having no side chains and in the absence of pronounced intermolecular interactions, it was found that standardization of Ecoh with reference to the number of structural elements capable of rather independent motions leads to a linear relationship between Tg, and Ecoh from which Tg, can be predicted. Without modifying our equation to suit the polymer, the influence of substituents and side chains can as yet only be assessed when they form a small part of the total segment. In the case of crosslinked epoxide systems, addition of the contribution made by crosslinking to the value of Tg, for the uncured polymer calculated from Ecoh results in a shift to higher Tg, values. In linear aliphatic polyamides and other polymers with analogous structure the formation of hydrogen bonds leads to an increase in Tg, comparable to the effect of chemical crosslinking. Reinforcing fillers also act as multifunctional crosslinks between the macromolecules and increase Tg. Just as Ecoh can be used to calculate Tg, experimentally readily ascertainable Tg values can be used to calculate Ecoh. This approach provides information on material properties like flexural strength at the yield point and torsional adhesive strength as well as on the effect of reinforcing fillers. 相似文献
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本文根据鲁尔区的产业发展总结了这一地区在20世纪的区域规划。自1871年统一为德意志帝国后,鲁尔区是德国最重要的经济地区之一,直至第一次世界大战(1914-1918)结束这里经历了经济发展的第一个阶段,二战(1939-1945)后又经历了第二个经济增长阶段。在这一时期形成的基础产业煤炭和钢铁生产在1970年代逐渐失去了发展动力,而此时在各地区都出现了新技术发展和新经济增长地区的形成。为了扭转衰败局面,鲁尔区以新规划思想为基础制定了新规划,利用了现有的最初是为工业地区组织的景观结构,并将其重新构造为后工业区域的景观系统。 相似文献
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Antigenotoxic effects of the phytoestrogen pelargonidin chloride and the polyphenol chlorogenic acid
Pelargonidin (PEL), a common anthocyanidin with estrogenic activity, was tested in HL-60 cells for its genotoxicity and possible antigenotoxic effects against 4-nitroquinoline 1-oxide (NQO), a potent mutagen and carcinogen which induces oxidative stress. To take into account potential interactions between phytochemicals within normal human nutrition, we evaluated a combination of PEL with the nonestrogenic phytochemical chlorogenic acid (CLA), one of the most abundant polyphenols in the human diet. PEL (< or = 2 microM) and CLA (< or = 800 microM) were nongenotoxic in the micronucleus test. We observed significant antigenotoxic effects against NQO with both compounds, but no additive interaction of PEL and CLA. Comet assay results showed a nonsignificant reduction in NQO-induced DNA damage with both compounds and their combination. Flow cytometric analysis of oxidative stress revealed significant protection against NQO-induced oxidative stress by PEL, CLA, and their combination. Furthermore, PEL and CLA prevented the NQO-induced reduction in GSH level. This could be a mechanism for the observed reduction in genotoxicity. In conclusion, the phytoestrogen PEL revealed antioxidative and antigenotoxic properties in HL-60 cells, but no significant additive interaction with the abundant nutritional polyphenol CLA under the tested conditions. 相似文献
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Mass spectrometry (MS) is increasingly being used for metabolic profiling, but detection modes such as constant neutral loss or multiple reaction monitoring have not often been reported. These modes allow focusing on structurally related compounds, which could be advantageous for situations in which the trait under investigation is associated with a particular class of metabolites. In this study, we analyzed endogenous glucuronides excreted in human urine by monitoring characteristic transitions of putative steroid glucuronides by LC-MS/MS for discrimination of females from males. Two methods for data extraction were used: (i) a manual procedure based on visual inspection of the chromatograms and selection of 23 peaks and (ii) a software-supported method (MarkerView) set to extract 100 peaks. Data from 10 female and 10 male students were analyzed by principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) using software SIMCA. With PCA, only the manual peak selection resulted in clustering males and females. With PLS-DA, the manual method provided full separation on the basis of one single discriminant; the software-supported approach required a two-component model for complete separation. Loading plots were analyzed for their ability to reveal peaks with high discriminating power, that is, potential biomarkers. The PLS-DA models were validated with urine samples collected from five new females and five new males. Gender was correctly assigned for all. Our results indicate that inclusion of biological criteria for variable selection coupled to class-specific MS analysis and data extraction by appropriate software may constitute a valuable addition to the methods available for metabolomics. 相似文献