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排序方式: 共有57条查询结果,搜索用时 81 毫秒
41.
P. Prati C. Arpesella F. Bartolucci H. W. Becker E. Bellotti C. Broggini P. Corvisiero G. Fiorentini A. Fubini G. Gervino F. Gorris U. Greife C. Gustavino M. Junker C. Rolfs W. H. Schulte H. P. Trautvetter D. Zahnow 《Zeitschrift für Physik A Hadrons and Nuclei》1994,350(2):171-176
Cross section measurements of thed(3He,p)4He reaction have been extended to an energy as low asE cm =5.4 keV. The data have an improved accuracy compared with previous work and confirm the existence of electron screening. The combined analysis of the present and previous data leads to an electron screening potential ofU e =123 ± 9 eV. A similar analysis of previous data for3He(d, p)4He leads toU e =186 ± 9 eV. Both screening potentials differ due to the molecular and atomic aggregate state of the targets involved in these investigations and are significantly larger than expected from available atomic physics models, supporting the general trend in studies of electron screening. 相似文献
42.
Lorenzo De Napoli Luciano Mayol Simonetta Bartolucci Gennaro Piccialli Mos Rossi Ciro Santacroce 《Journal of heterocyclic chemistry》1988,25(3):1039-1042
The paper reports the synthesis and physico-chemical data of eight new pyrimidine nucleosides C-4 substituted and two imidazo[1,2-c]pyrimidine nucleosides as well as preliminary results of their biological effects on neuroblastoma cells in culture. 相似文献
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Pacenti M Dugheri S Villanelli F Bartolucci G Calamai L Boccalon P Arcangeli G Vecchione F Alessi P Kikic I Cupelli V 《Biomedical chromatography : BMC》2008,22(10):1155-1163
A method for the determination of the organic acids directly in the urine employing derivatization with trimethyloxonium tetrafluoroborate as a methylating agent and sequential extraction by head space and direct immersion/solid phase microextraction is reported. Furoic acid, hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid and trans, trans muconic acid contained in urine and proposed by the American Conference of Governmental Industrial Hygienists as biological exposure indices were determined after a fast and economically convenient preparation step and sensitive gas chromatography-ion trap-mass spectrometry/tandem mass spectrometry analysis. Urine is rather a complex sample and hence the acquisition method required specific GC-MS instrumentation capable of supporting the changeover, fully automated during a single chromatographic separation, from mass to tandem mass spectrometry and both chemical and electron ionization modes. The automation of the analytical method provides a number of advantages, including reduced analysis time for both routine analysis and method development, and greater reproducibility. The equilibrium and kinetics of this substances vs head space/direct immersion-solid phase microextraction were investigated and evaluated theoretically. 相似文献
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Niccol Chiaramonte Alessio Gabellini Andrea Angeli Gianluca Bartolucci Laura Braconi Silvia Dei Elisabetta Teodori Claudiu T. Supuran Maria Novella Romanelli 《Molecules (Basel, Switzerland)》2022,27(2)
A series of histamine (HST)-related compounds were synthesized and tested for their activating properties on five physiologically relevant human Carbonic Anhydrase (hCA) isoforms (I, II, Va, VII and XIII). The imidazole ring of HST was replaced with different 5-membered heterocycles and the length of the aliphatic chain was varied. For the most interesting compounds some modifications on the terminal amino group were also performed. The most sensitive isoform to activation was hCA I (KA values in the low micromolar range), but surprisingly none of the new compounds displayed activity on hCA II. Some derivatives (1, 3a and 22) displayed an interesting selectivity for activating hCA I over hCA II, Va, VII and XIII. 相似文献
47.
The power of energy‐resolved tandem mass spectrometry experiments for resolution of isomers: the case of drug plasma stability investigation of multidrug resistance inhibitors 下载免费PDF全文
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Michela Gnaldi Silvia Bacci Francesco Bartolucci 《Advances in Data Analysis and Classification》2016,10(1):53-70
Within the educational context, a key goal is to assess students’ acquired skills and to cluster students according to their ability level. In this regard, a relevant element to be accounted for is the possible effect of the school students come from. For this aim, we provide a methodological tool which takes into account the multilevel structure of the data (i.e., students in schools) and allows us to cluster both students and schools into homogeneous classes of ability and effectiveness, and to assess the effect of certain students’ and school characteristics on the probability to belong to such classes. The proposed approach relies on an extended class of multidimensional latent class IRT models characterised by: (i) latent traits defined at student and school level, (ii) latent traits represented through random vectors with a discrete distribution, (iii) the inclusion of covariates at student and school level, and (iv) a two-parameter logistic parametrisation for the conditional probability of a correct response given the ability. The approach is applied for the analysis of data collected by two national tests administered in Italy to middle school students in June 2009: the INVALSI Language Test and the Mathematics Test. 相似文献
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A facile synthetic approach to the direct preparation of various novel unnatural boronated protected tryptophans using a regio- and chemoselective electrophilic substitution of 4- and 5-boronated indoles with N-protected dehydroalanine is described. The gram-scale synthesis of two free tryptophan boronic acids is also reported. 相似文献