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21.
The seed oil of Sebastiana commersoniana (Euphorbiaceae) was separated into a triglyceride and an estolide fraction by preparative thin-layer chromatography. The
triglyceride band was characterized by spectroscopic methods, and its fatty acids have been analyzed by gas chromatography
(GC) and GC-mass spectrometry (MS) and their methyl esters. Linolenic acid was the main fatty acid (65%). The estolide band
was examined by a combination of spectroscopic and chromatographic methods (ultraviolet, infrared, nuclear magnetic resonance,
fast atom bombardment-MS, GC-MS of the fatty acids before and after silylation) and was identified as a tetraglyceride, where
on α-carbon of the glyceride backbone was esterfied with 8-hydroxy-5,6-octadienoic acid, which itself was esterfied with trans-2,cis-4-decadienoic acid. The remaining positions of the glyceride backbone were occupied by common fatty acids.
This work was presented in part at the 87th Annual Meeting of the American Oil Chemists’ Society, April 28–May 1, 1996, Indianapolis,
Indiana. 相似文献
22.
Roland Schmidt Ulrich Hammon Stefan Gottfried M. Bruce Welch Helmut G. Alt 《应用聚合物科学杂志》2003,88(2):476-482
The synthesis of iron(II) complexes with various tridentate di(imino)pyridine ligands and their potential as ethene oligomerization catalysts are described. The ligands are characterized by 1H‐ and 13C‐NMR spectroscopy and the complexes only by mass spectrometry due to their paramagnetism. After activation either with methylalumoxane (MAO) or with a heterogeneous cocatalyst consisting of partially hydrolyzed trimethylaluminum and silica gel, the prepared complexes proved to be good catalysts for the oligomerization of ethene. 1‐Octene, 1‐hexene, and 1‐decene were the major products, formed in very high isomeric purity (99.9 %). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 476–482, 2003 相似文献
23.
Two studies, 1 longitudinal and 1 cross-sectional, demonstrate that for young elementary school children, academic intrinsic motivation is a reliable, valid, and significant construct. It was positively related to achievement, IQ, and perception of competence, and inversely related to anxiety. Academic intrinsic motivation at age 9 was significantly predicted by motivation measured 1 and 2 years earlier, above and beyond the contribution of IQ and achievement. Children with higher academic intrinsic motivation at ages 7 and 8 were more likely to show higher motivation at age 9. Whereas young children could reliably distinguish between subject areas of academic intrinsic motivation, only math motivation showed consistently specific relations to other math criteria. Findings are discussed with regard to developmental theories of intrinsic motivation and the significance of academic intrinsic motivation for children's education. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
24.
Cynthia J. Finelli Molly Ott Amy C. Gottfried Chad Hershock Christopher O'Neal Matthew Kaplan 《工程教育杂志》2008,97(4):397-411
Although many kinds of data can be used to guide instructional consultations, research comparing the efficacy of such data is scant, especially in engineering. In this study, multiple modes of assessment were used to evaluate the impact of consultations informed by different kinds of data. This study illuminates two key aspects of instructional consultations: (1) their efficacy varies depending on the kind of data used to guide them, with student feedback from a Small Group Instructional Diagnosis (SGID) having the largest positive impact, and (2) the instructional consultant plays a key role in helping both interpret the available data and identify strategies for improvement. These findings suggest three implications for practice: (1) whenever possible, SGID‐based consultations should be offered systematically and proactively for engineering faculty, (2) data for other kinds of consultations should be tailored to the needs of the individual instructor, and (3) instructional consultants should be available to collaborate with faculty to enhance their teaching, thereby building an engineering culture that actively supports teaching and learning. 相似文献
25.
Dieter Enders Katharina Gottfried Gerhard Raabe 《Advanced Synthesis \u0026amp; Catalysis》2010,352(18):3147-3152
The first organocatalytic enantioselective Strecker synthesis of α‐quaternary α‐trifluoromethylated amino acids has been developed. Employing Takemoto’s thiourea catalyst the nucleophilic addition of trimethylsilyl cyanide to trifluoromethyl ketimines affords α‐amino nitriles in good to excellent yields (50–99%) and very good enantioselectivities (ee=83–95%). The enantiopure amino nitriles can be obtained by recrystallization. Deprotection and hydrolysis leads to the title amino acids. 相似文献
26.
Gottfried Ziegleder 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1990,191(4-5):306-309
Summary The terpenes present in cocoa flavour were analysed by means of gas chromatography-mass spectrometry. The pyranoid linalool oxides, ocimene and nerolidol, were identified for the first time as cocoa volatiles. Linalool, which is the major terpene component in cocoa contributes markedly to the flowery and tea-like flavour of some cocoa varieties. Flavour grade beans contain relatively high concentrations of linalool and basic grade cocoas possess. The isolation of linalool by means of intensive (simultaneous distillation extraction) and more gentle methods (vacuum condensation) yields similar quantitative results. The estimation of the concentration ratio of linalool/benzaldehyde within steam distillates ist suitable for the industrial quality control of unroasted cocoas.
Linaloolgehalt als Merkmal einiger Edelkakaos
Zusammenfassung In Kakaoaroma wurden anhand GC/MS einige Terpene nachgewiesen, darunter erstmals auch die pyranoiden Linalooloxide, Ocimen und Nerolidol. Linalool als Hauptkomponente dieser Gruppe trägt wesentlich zum blumigen und tee-artigen Aroma einiger Kakaosorten bei. Edelkakaos weisen relativ hohe, Konsumkakaos niedrige Linalool-Konzentrationen auf. Die Isolierung von Linalool unter drastischen (simultane Destillation Extraktion) und milden Bedingungen (Vakuum-Kondensation) liefert ähnliche quantitative Ergebnisse. Die Bestimmung des Konzentrationsverhältnisses von Linalool/Benzaldehyd in Wasserdampfdestillaten eignet sich zur industriellen Qualitätskontrolle von Rohkakao.相似文献
27.
Gottfried Biegelmeier und Klaus Harms 《e & i Elektrotechnik und Informationstechnik》1999,116(10):617
Ohne Zusammenfassung 相似文献
28.
29.
The author offers the opinion that the adoption of the terminology of hardware reliability in the context of software was a terrible, probably unavoidable, and perhaps even necessary, mistake: terrible-because the words cannot have the same meanings in both contexts; and unavoidable-because today there are few systems whose reliability can be assessed without dealing with both 相似文献
30.
G. Kappeller und A. Gottfried 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1916,31(1):1-6
Ohne Zusammenfassung
Mitteilung aus dem st?dtischen Nahrungsmittel-Untersuchungsamte Magdeburg. 相似文献