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51.
R. Bailey E. R. Belau T. Böhringer M. Bosman V. Chabaud C. Damerell C. Daum H. Dijkstra S. Gill A. Gillman R. S. Gilmore Z. Hajduk C. Hardwick W. Hoogland B. D. Hyams J. Kemmer R. Klanner U. Kötz S. W. L. Kwan G. Lütjens G. Lutz J. Malos W. Männer E. Neugebauer H. Paŀka M. Pepe J. Richardson G. de Rijk M. Rozanska K. Rybicki H. Seebrunner U. Stierlin R. J. Tapper H. G. Tiecke M. Turala G. Waltermann P. Weilhammer F. Wickens L. W. Wiggers A. Wylie T. Zeludziewicz ACCMOR-Collaboration 《Zeitschrift fur Physik C Particles and Fields》1986,30(1):51-63
We have measured the differential and total cross sections ofD meson production in 200 GeV π?-beryllium interactions, using a sample of 48 fully reconstructed and nearly background-freeD mesons in the decay channelsK ?π±,K ?π±π± andK ?π?π±π±. A single electron trigger has been used to select events containing a pair of charmed particles. A vertex telescope of 6 silison microstrip detectors allowed the reconstruction of tracks of charged secondaries and the reconstruction of primary and decay vertices with high precision. The ratio of branching fractions for \(\mathop {D^0 }\limits^{( - )} \to K^ \mp \pi ^ \pm \) to \(\mathop {D^0 }\limits^{( - )} \to K^ \mp \pi ^ \mp \pi ^ \pm \pi ^ \pm \) , and an upper limit for \(D^0 - \bar D^0 \) mixing are presented. 相似文献
52.
53.
Joss Pepe Strache Lukas Münzer Andreas Adler Dr. Dirk Blunk Prof. Dr. Hans-Günther Schmalz 《European journal of organic chemistry》2023,26(10):e202300050
We investigated the previously unknown enantioselective Ni-catalyzed hydrocyanation of 1,3-diarylpropenes (homostilbenes). For this purpose, a series of (E)-homostilbenes were prepared by (microwave-assisted) Pd-catalyzed coupling of allylic alcohols with aryl-boronic acids. Employing our established catalyst system formed from Ni(cod)2 and a TADDOL-derived chiral phosphine-phosphite ligand and using TMSCN as an in situ source of HCN, the hydrocyanation of various homostilbenes was studied. The synthetic usefulness of the methodology was demonstrated in a short synthesis of the new (allo-) colchicine analogue 7-cyano-11-methoxy-colchinol involving an PIDA-mediated oxidative cyclization of the corresponding hydrocyanation product to set up the 7-membered ring. The absolute configuration of 2,4-diphenylbutyronitrile was assigned by comparison of experimental and calculated ECD spectra. 相似文献
54.
55.
H. Fawcett S. Barlag H. Becker E. Belau T. Böhringer M. Bosman V. Chabaud D. Bucholz V. Castillo C. Damerell C. Daum G. De Rijk H. Dietl S. Gill A. Gillman R. Gilmore T. Gooch P. Gras Z. Hajduk E. Higon B. Hyams D. Kelsey J. Kemmer R. Klanner U. Kötz S. Kwan B. Lücking G. Lütjens G. Lutz J. Malos W. Männer E. Neugebauer H. Palka M. Pepe G. Polok J. Richardson M. Rozanska K. Rybicki H. Seebrunner U. Stierlin R. Tapper H. Tiecke M. Turala G. Waltermann S. Watts P. Weilhammer F. Wickens L. Wiggers A. Wylie T. Zeludziewicz ACCMOR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,46(4):521-524
Data on the production of the neutralK *(892) resonances at lowp t by 200 GeVK ? and π? is compared with the predictions of various models based on the quark parton model of hadrons. 相似文献
56.
Mezzache S Pepe C Karoyan P Fournier F Tabet JC 《Rapid communications in mass spectrometry : RCM》2005,19(16):2279-2283
The proton affinity (PA) of cis/trans-3-prolinoleucines and cis/trans-3-prolinoglutamic acids have been studied by the kinetic method and density functional theory (DFT) calculations. Several conformations of the neutral and the protonated modified prolines, in particular the endo and exo ring conformations, were analyzed with respect to their contribution to the PA values. When the substituent is an alkyl, both the diastereoisomers have the same PA value. However, the PA values for the diastereoisomers are different when the substituted chain contains functional groups (e.g. a carboxyl group). This variation in PA values could be attributed to the existence of intramolecular hydrogen bonds. 相似文献
57.
Bochicchio B Jimenez-Oronoz F Pepe A Blanco M Sandberg LB Tamburro AM 《Macromolecular bioscience》2005,5(6):502-511
Little data exist on the structure and function of compressible elastomeric proteins such as abductin. An understanding of the underlying structural features of these proteins may lead to the development of a new class of highly tailored "compressible" hydrogels. To that effect, in this work, the structure of abductin was investigated by means of studies on several synthetic peptides corresponding to the most frequent sequences of abductin. In particular, the 10 amino acid abductin peptide sequence FGGMGGGNAG, tandem repeated in the protein, and two related 25 and 40 amino acid polypeptides were synthesized. These peptides were studied with regard to secondary structure, self-assembly, and polymer morphology. The results obtained with these peptides allow us to propose a preliminary structure-elasticity relationship for abductin not dissimilar from that currently accepted for elastin.A possible mechanism of elasticity relating abductin to elastin. 相似文献
58.
Determining pirimiphos-methyl in durum wheat samples using an acetylcholinesterase inhibition assay 总被引:2,自引:0,他引:2
Del Carlo M Pepe A Mascini M De Gregorio M Visconti A Compagnone D 《Analytical and bioanalytical chemistry》2005,381(7):1367-1372
An electrochemical assay used for detecting acetylcholinesterase (AChE) inhibitors has been optimised to detect pirimiphos-methyl in durum wheat. Pirimiphos-methyl is a phosphothionate insecticide and so it needs to be transformed into the corresponding oxo form to act as an effective AChE inhibitor. The inhibition assay was based on the electrochemical detection of the product of AChE, choline, via choline oxidase biosensors obtained with Prussian-Blue modified screen printed electrodes. The procedure for the oxidation of pirimiphos methyl via N-bromosuccinimide (NBS) and AChE inhibition was optimised for reagent concentrations and inhibition time in a buffer solution. A calibration of the pirimiphos-methyl (25–1,000 ng/ml) was obtained in the buffer. The intra-electrode CV ranged between 1.6 and 15.0, whereas the inter-electrode CV ranged between 4.6 and 16.0. The detection limit (LOD) was 38 ng/ml, and the I50% was 360 ng/ml. The assay conditions were then re-optimised to work with durum wheat extracts, and the calibrations were obtained under different experimental conditions, such as sample pretreatment (milled or whole grains) and extract concentration. The calibrations were slightly affected by the sample matrix, resulting in an increased LOD (65–133 ng/ml) and I50% (640–1,650 ng/ml). The LOD found for the sample, determined under optimal conditions, was 3 mg/kg. Spiked samples were prepared at the EU regulated level (5 mg/kg) and analysed with the optimised protocol, resulting in an average recovery of 70.3%. 相似文献
59.
C. Angeletti F. Pepe P. Porta M. Schiavello 《Reaction Kinetics and Catalysis Letters》1979,9(4):353-357
The results show that there is not difference between the catalytic activities of two series of CuxMg1–xAl2O4 catalysts, despite a small but significant difference in cation distribution. The activity is mainly affected by the presence of CuO.
, , , , - CuXMg1–XAl2O4. CuO.相似文献
60.
S. Barlag H. Becker T. Böhringer M. Bosman V. Castillo V. Chabaud C. Damerell C. Daum H. Dietl A. Gillman R. Gilmore T. Gooch L. Görlich P. Gras Z. Hajduk E. Higon D. P. Kelsey R. Klanner S. Kwan B. Lücking G. Lütjens G. Lutz J. Malos W. Männer E. Neugebauer H. Palka M. Pepe J. Richardson K. Rybicki H. J. Seebrunner U. Stierlin H. G. Tiecke G. Waltermann S. Watts P. Weilhammer F. Wickens L. W. Wiggers M. Witek T. Zeludziewicz ACCMOR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,48(1):29-45
In the CERN NA 32 experiment a high-resolution silicon vertex detector and a purely topological approach have been used to investigate various decays of charmed particles. We observe ~620 fully reconstructed decays ofD 0 in 12 channels and determine the branching ratios. For fourD 0 decay modes involving a single (unseen) π0 the small and narrowD *+?D 0 mass difference is used to measure their branching ratios. We also observe ~280 fully reconstructedD + decays in 10 channels, ~90D s + decays in 11 channels as well as 160Λ s c and 18 decay channels ofD +. For theD s + , we measure the branching fractions within a subset of 16 three- and five-prong decay channels. For theΛ s c , we determine the branching fractions within a sample of 11 three- and five-prong decay channels, nearly all involving a proton. 相似文献