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941.
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Dr. Cezary Pietraszuk Dr. Szymon Rogalski Beata Powała Miłosz Miętkiewski Dr. Maciej Kubicki Grzegorz Spólnik Prof. Dr. Witold Danikiewicz Krzysztof Woźniak Aleksandra Pazio Dr. Anna Szadkowska Anna Kozłowska Prof. Dr. Karol Grela 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(21):6465-6469
944.
Mariana Tătucu Petre Rotaru Ileana Rău Cezar Spînu Angela Kriza 《Journal of Thermal Analysis and Calorimetry》2010,100(3):1107-1114
Pyridine derivative complexes are widely employed as biological active materials especially as antibacterial agents. Five transition metal(II) mpk complexes (mpk = methyl 2-pyridyl ketone) were synthesized and investigated using elemental analysis, spectroscopic techniques (IR and UV–Vis–NIR) and conductometric measurements. The general formulae established from experimental data were found to be [M(mpk)2(NO3)2]·xH2O (x = 0 for M = Cd(II), Zn(II), x = 2 for M = Cu(II)) and [M(mpk)2(H2O)2](NO3)2 (M = Co(II), Ni(II)). These compositions were further confirmed by thermal analysis and their thermal stability in dynamic air atmosphere investigated. 相似文献
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947.
Gordon PM Weinel C Jacobi C Kämpf U Kriventseva E Sensen CW 《Analytica chimica acta》2006,564(1):123-132
We have created an analysis pipeline called Sprockets, which can be used to classify proteins into various hierarchical “families”, and build searchable models of these families. The construction of these families is based on data from Expressed Sequence Tags (ESTs) and Coding DNA Sequences (CDSs), making Sprockets clusters especially suitable for studying gene families in organisms for which the completely sequenced genome does not (yet) exist. The pipeline consists of two main parts: pair-wise analysis and grouping of sequences with Z-score statistics, followed by hierarchical splitting of clusters into alignable protein families. Various computational and statistical techniques applied in Sprockets allow it to act like a massive and selective multiple sequence alignment engine for combining individual sequence collections and related public sequences. The end result is a database of gene Hidden Markov Models, each related to the other by three levels of similarity: secondary structure, function and evolutionary origin. For a sample 20,000 EST set from Lactuca spp., Sprockets provided a 9% improvement in mapping of function to unknown sequences over traditional pair-wise search methods and InterPro mapping. 相似文献
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949.
Steinbach C Fárník M Buck U Brindle CA Janda KC 《The journal of physical chemistry. A》2006,110(29):9108-9115
Clusters of krypton are generated in a supersonic expansion and size selected by deflection from a helium target beam. By measuring angular distributions for different fragment masses and time-of-flight distributions for fixed deflection angles and fragment masses, the complete fragmentation patterns for electron impact ionization at 70 eV are obtained from the dimer to the heptamer. For each of the neutral Kr(n) clusters studied, the main fragment is the monomer Kr(+) ion with a probability f(n)(1) > 90%. The probability of observing dimer Kr(2)(+) ions is much smaller than expected for each initial cluster size. The trimer ion Kr(3)(+) appears first from the neutral Kr(5), and its fraction increases with increasing neutral cluster size n, but is always much smaller than that of the monomer or dimer. For neutral Kr(7), all possible ion fragments are observed, but the monomer still represents 90% of the overall probability and fragments with n > 3 contribute less than 1% of the total. Aspects of the Kr(n) cluster ionization process and the experimental measurements are discussed to provide possible reasons for the surprisingly high probability of observing fragmentation to the Kr(+) monomer ion. 相似文献
950.
Fárník M Weimann M Steinbach C Buck U Borho N Adler TB Suhm MA 《Physical chemistry chemical physics : PCCP》2006,8(10):1148-1158
A comprehensive experimental study of the OH stretching vibrations of size-selected clusters of enantiopure and racemic methyl lactate is presented. For the size selection, we measured angular dependent mass spectra and time-of-flight distributions at the different fragment masses. In this way the fragmentation of these clusters upon electron impact ionization is obtained. The largest fragment masses of the neutral (MLac)n clusters are the protonated (MLac)n-1H+ ions. The results of a pressure dependent study in an FTIR jet experiment are compared with completely size-selected experiments based on atomic beam deflection and depletion spectroscopy. The size assignments and spectra agree for dimers and trimers. Structures and spectral information for the trimer and the tetramer at density functional and MP2 level are provided. Selective self-aggregation and chiral recognition was observed for homochiral trimers. They exhibit a ring structure bound by OH...OH hydrogen bonds. A spectacular switch in the hydrogen bonding topology was observed for the tetramer. The homochiral enantiomer exhibits cooperative OH...OH bonding, while the heterochiral version shows isolated OH...O=C bonding in a symmetric SRSR arrangement. The crucial ingredients for this identification are the size-selective IR spectra with their different shifts and line patterns which are reproduced by the calculations. 相似文献