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61.
62.
A two step sequence converts certain cyclic enones to fused methylenecyclopentanes using the annulation reagent 2-chloromethyl-3-trimethylsilylpropene. 相似文献
63.
Investigations of microwave assisted drying of sample materials and microwave assisted evaporation of aqueous sample solutions and acidic digestion residues were accomplished by means of special rotors for the microwave digestion system MULTIWAVE. To check the results obtained by microwave assisted drying, the samples were also conventionally dried at 105?°C in an oven. The following samples have been dried: 10 g each of meat, fish, apple, cucumber, potato, mustard, yogurt, clay and marl; 1 g each of certified reference material TORT 2 (lobster hepatopancreas), BCR 278 (mussel tissue) and BCR 422 (cod muscle); 500 g garden mould. Microwave assisted drying takes 40 min for organic samples and ¶30 min for inorganic material. Important is a slow increase of microwave power during the first 20 min. The results agree well with conventional drying at 105?°C. Losses of As, Se and Hg have been investigated for ¶3 CRMs. Only Se shows losses in the range of 20%. Losses of As, Be, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, Tl, V and Zn after evaporation of aqueous samples and acidic solutions after wet digestion, respectively, have been investigated. 50 mL aqueous solution was evaporated almost to dryness within 25 min. The recovery of Hg is 40–50%, of Se 90–95% and of the other elements 97–102%. 0.2 g each of TORT 2, BCR 278 and BCR 422 have been digested with 4 mL nitric acid and 1 mL hydrochloric acid by means of the microwave digestion system MULTIWAVE. The digestion residue was evaporated almost to dryness and dissolved again in 10 mL diluted nitric acid. In this case no element losses have been observed. The measured concentration of As, Cd, Cu, Fe, Mn, Hg, Pb, Mo, Ni, Se, Sr, V and Zn agree very well with the certified values. An important prerequisite for good recoveries is not to evaporate the solutions to complete dryness. 相似文献
64.
Fedorov O Huber K Eisenreich A Filippakopoulos P King O Bullock AN Szklarczyk D Jensen LJ Fabbro D Trappe J Rauch U Bracher F Knapp S 《Chemistry & biology》2011,18(1):67-76
There is a growing recognition of the importance of protein kinases in the control of alternative splicing. To define the underlying regulatory mechanisms, highly selective inhibitors are needed. Here, we report the discovery and characterization of the dichloroindolyl enaminonitrile KH-CB19, a potent and highly specific inhibitor of the CDC2-like kinase isoforms 1 and 4 (CLK1/CLK4). Cocrystal structures of KH-CB19 with CLK1 and CLK3 revealed a non-ATP mimetic binding mode, conformational changes in helix αC and the phosphate binding loop and halogen bonding to the kinase hinge region. KH-CB19 effectively suppressed phosphorylation of SR (serine/arginine) proteins in cells, consistent with its expected mechanism of action. Chemical inhibition of CLK1/CLK4 generated a unique pattern of splicing factor dephosphorylation and had at low nM concentration a profound effect on splicing of the two tissue factor isoforms flTF (full-length TF) and asHTF (alternatively spliced human TF). 相似文献
65.
A novel automated liquid/liquid extraction system was developed for the determination of trace contaminants in unalloyed,
alloyed and highly alloyed steels and super alloys. In the presented batch extraction system the aqueous phase and the non-water
miscible organic phase were brought into close phase contact by high-speed stirring with a magnetic stir bar. Iodide complexes
of Ag, Bi, Cd, Pb, Sb, Sn, Tl, and Zn were extracted from aqueous steel digests into 4-methylpentan-2-one (MIBK) containing
20 g L−1 trioctylphosphine oxide. Ag, Bi, Cd, Pb, and Tl were extracted quantitatively whereas the extraction yields of Sb, Sn, and
Zn were 83%, 61% and 75% respectively. Using high resolution continuum source flame AAS (HR-CS-FAAS) for analyte quantification
the method was validated using 21 certified steel reference materials (CRMs). 相似文献
66.
Ohne Zusammenfassung 相似文献
67.
Walter Knapp 《Monatshefte für Chemie / Chemical Monthly》1930,56(1):66-70
Ohne Zusammenfassung 相似文献
68.
J. L. Baker H. F. E. Huiton K. Hoepner A. W. Knapp B. G. Mc Lellan Th. v. Fellenberg Ch. Arragon J. Grossfeld H. Jaeger H. Eggers P. Hasse und Elisabeth Bake 《Fresenius' Journal of Analytical Chemistry》1924,65(10):427-432
Ohne Zusammenfassung 相似文献
69.
W. Knapp 《Monatshefte für Chemie / Chemical Monthly》1937,71(1):440-443
Ohne ZusammenfassungMeinen Bestrebungen kam erneut eine dankenswerte Beihilfe seitens des Herrn Professors H.MARK zustatten. 相似文献
70.
W. Knapp 《Monatshefte für Chemie / Chemical Monthly》1937,70(1):251-258
Ohne ZusammenfassungDiese Arbeit erfuhr wieder eine sehr dankenswerte Förderung durch Herrn Prof. H.Mark. 相似文献