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排序方式: 共有9839条查询结果,搜索用时 15 毫秒
991.
Zuzana Jehliková Jana Hajlová Jan Poustka Frantiek Pudil Jii Davidek 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1990,190(5):436-440
Summary A reproducible and sensitive gas Chromatographic method has been developed for the trace analysis of fluazifop-butyl, haloxyfop-ethoxyethyl and quizalofop-ethyl as well as their main metabolites (corresponding acids analysed after conversion to methyl esters) in some fruits and vegetables treated with herbicidal sprays. Comparable detection limits (0.01 mg/kg) were achieved when mass fragmentography and/or the electron capture detector were employed. However, in the latter case, bromination of fluazifop esters had to be carried out prior to GC analysis. By means of the nitrogen-phosphorus detector, determination of residues at a level of 0.05 mg/kg was possible. The residue values found in strawberries, cabbages, cauliflowers and carrots were used to discuss the degree of metabolic hydrolysis of parent esters, i.e. active ingredients of herbicides.
Bestimmung von Aryloxyphenoxypropionsäure-Derivaten in mit Herbicidsprays behandelten Produkten
Zusammenfassung Es wurde eine gaschromatographische Methode zur quantitativen und selektiven Bestimmung von Fluazifop-butyl, Haloxyfop-ethoxyethyl und Quizalofop-ethyl sowie von ihren Hauptmetaboliten (den entsprechenden Säuren, die zu Methylestern umgesetzt werden müssen) in mit Herbiciden behandelten Obst- und Gemüseproben entwickelt. Eine Nachweisgrenze von 0,01 mg/kg wurde durch Elektroneneinfanggaschromatographie oder durch Massenfragmentographie erzielt. Um die gleiche Empfindlichkeit des EC-Detektors bei Fluazifop zu erreichen, wurden die beiden Ester mit Brom umgesetzt. Mit Hilfe des NP-Detektors konnte eine Nachweisgrenze von 0,05 mg/kg erreicht werden. Die festgestellten Rückstandsgehalte in Erdbeeren, Kohl, Blumenkohl und Möhren wurden gleichzeitig zur Beurteilung der metabolischen Hydrolyse der diskutierten Ester (der Wirkstoffe der Herbicide) herangezogen.相似文献
992.
Joint investigation of concrete at high rates of loading 总被引:2,自引:0,他引:2
Uniaxial tensile tests have been carried out on a micro-concrete with strain rates between 0.5 and 1.25 s−1. The investigation is described and the results are discussed with respect to the influence of water content on the strain-rate
sensitivity. 相似文献
993.
James E. Oliver John W. Neal Jr. William R. Lusby Jeffrey R. Aldrich Jan P. Kochansky 《Journal of chemical ecology》1985,11(9):1223-1228
The azalea lace bug secretes a clear fluid from secretory setae on the antennae and globulated spines on the dorsal and lateral aspects of the abdomen. The secretion contains 2-alkyl-5-hydroxychromones, the corresponding chromanones and diketones, and straight-chain aldehydes and ketones. 相似文献
994.
995.
Jan?van den?Broek Jennifer?L.?M.?RuppEmail author Semih?AfyonEmail author 《Journal of Electroceramics》2017,38(2-4):182-188
All-solid-state batteries based on fast Li+ conducting solid electrolytes such as Li7La3Zr2O12 (LLZO) give perspective on safe, non-inflammable, and temperature tolerant energy storage. Despite the promise, ceramic processing of whole battery assemblies reaching close to theoretical capacities and finding optimal strategies to process large-scale and low cost battery cells remains a challenge. Here, we tackle these issues and report on a solid-state battery cell composed of Li4Ti5O12 / c-Li6.25Al0.25La3Zr2O12 / metallic Li delivering capacities around 70–75 Ah/kg with reversible cycling at a rate of 8 A/kg (for 2.5–1.0 V, 95 °C). A key aspect towards the increase in capacity and Li+ transfer at the solid electrolyte-electrode interface is found to be the intimate embedding of grains and their connectivity, which can be implemented by the isostatic pressing of cells during their preparation. We suggest that simple adaption of ceramic processing, such as the applied pressure during processing, strongly alters the electrochemical performance by assuring good grain contacts at the electrolyte-electrode interface. Among the garnet-type all-solid-state ceramic battery assemblies in the field, considerably improved capacities and cycling properties are demonstrated for Li4Ti5O12 / c-Li6.25Al0.25La3Zr2O12 / metallic Li pressed cells, giving new perspectives on cheap ceramic processing and up-scalable garnet-based all-solid-state batteries. 相似文献
996.
997.
998.
Sphinganine‐Like Biogenesis of (E)‐1‐Nitropentadec‐1‐ene in Termite Soldiers of the Genus Prorhinotermes
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Dr. Anna Jirošová Dr. Pavel Majer Andrej Jančařík Klára Dolejšová Dr. Richard Tykva Dr. Jan Šobotník Dr. Pavel Jiroš Dr. Robert Hanus 《Chembiochem : a European journal of chemical biology》2014,15(4):533-536
In 1974, (E)‐1‐nitropentadec‐1‐ene, a strong lipophilic contact poison of soldiers of the termite genus Prorhinotermes, was the first‐described insect‐produced nitro compound. However, its biosynthesis remained unknown. In the present study, we tested the hypothesis that (E)‐1‐nitropentadec‐1‐ene biosynthesis originates with condensation of amino acids with tetradecanoic acid. By using in vivo experiments with radiolabeled and deuterium‐labeled putative precursors, we show that (E)‐1‐nitropentadec‐1‐ene is synthesized by the soldiers from glycine or L ‐serine and tetradecanoic acid. We propose and discuss three possible biosynthetic pathways. 相似文献
999.
Immune and Anticancer Responses Elicited by Fully Synthetic Aberrantly Glycosylated MUC1 Tripartite Vaccines Modified by a TLR2 or TLR9 Agonist
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Dr. Abu‐Baker M. Abdel‐Aal Dr. Vani Lakshminarayanan Dr. Pamela Thompson Nitin Supekar Judy M. Bradley Dr. Margreet A. Wolfert Prof. Dr. Peter A. Cohen Prof. Dr. Sandra J. Gendler Prof. Dr. Geert‐Jan Boons 《Chembiochem : a European journal of chemical biology》2014,15(10):1508-1513
The mucin MUC1 is overexpressed and aberrantly glycosylated by many epithelial cancer cells manifested by truncated O‐linked saccharides. Although tumor‐associated MUC1 has generated considerable attention because of its potential for the development of a therapeutic cancer vaccine, it has been difficult to design constructs that consistently induce cytotoxic T‐lymphocytes (CTLs) and ADCC‐mediating antibodies specific for the tumor form of MUC1. We have designed, chemically synthesized, and immunologically examined vaccine candidates each composed of a glycopeptide derived from MUC1, a promiscuous Thelper peptide, and a TLR2 (Pam3CysSK4) or TLR9 (CpG‐ODN 1826) agonist. It was found that the Pam3CysSK4‐containing compound elicits more potent antigenic and cellular immune responses, resulting in a therapeutic effect in a mouse model of mammary cancer. It is thus shown, for the first time, that the nature of an inbuilt adjuvant of a tripartite vaccine can significantly impact the quality of immune responses elicited against a tumor‐associated glycopeptide. The unique adjuvant properties of Pam3CysSK4, which can reduce the suppressive function of regulatory T cells and enhance the cytotoxicity of tumor‐specific CTLs, are likely responsible for the superior properties of the vaccine candidate 1 . 相似文献
1000.