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排序方式: 共有111条查询结果,搜索用时 15 毫秒
41.
Khachatryan V Sirunyan AM Tumasyan A Adam W Bergauer T Dragicevic M Erö J Fabjan C Friedl M Frühwirth R Ghete VM Hammer J Hänsel S Hartl C Hoch M Hörmann N Hrubec J Jeitler M Kasieczka G Kiesenhofer W Krammer M Liko D Mikulec I Pernicka M Rohringer H Schöfbeck R Strauss J Taurok A Teischinger F Wagner P Waltenberger W Walzel G Widl E Wulz CE Mossolov V Shumeiko N Suarez Gonzalez J Benucci L Cerny K De Wolf EA Janssen X Maes T Mucibello L Ochesanu S Roland B Rougny R Selvaggi M Van Haevermaet H 《Physical review letters》2011,106(20):201802
A search for pair production of first-generation scalar leptoquarks is performed in the final state containing two electrons and two jets using proton-proton collision data at √s = 7 TeV. The data sample used corresponds to an integrated luminosity of 33 pb?1 collected with the CMS detector at the CERN LHC. The number of observed events is in good agreement with the predictions for the standard model background processes, and an upper limit is set on the leptoquark pair production cross section times β2 as a function of the leptoquark mass, where β is the branching fraction of the leptoquark decay to an electron and a quark. A 95% confidence level lower limit is set on the mass of a first-generation scalar leptoquark at 384 GeV for β = 1, which is the most stringent direct limit to date. 相似文献
42.
Chatrchyan S Khachatryan V Sirunyan AM Tumasyan A Adam W Bergauer T Dragicevic M Erö J Fabjan C Friedl M Frühwirth R Ghete VM Hammer J Hänsel S Hoch M Hörmann N Hrubec J Jeitler M Kiesenhofer W Krammer M Liko D Mikulec I Pernicka M Rohringer H Schöfbeck R Strauss J Taurok A Teischinger F Wagner P Waltenberger W Walzel G Widl E Wulz CE Mossolov V Shumeiko N Gonzalez JS Bansal S Benucci L De Wolf EA Janssen X Maes J Maes T Mucibello L Ochesanu S Roland B Rougny R Selvaggi M Van Haevermaet H 《Physical review letters》2011,107(20):201804
A study of events with missing transverse energy and an energetic jet is performed using pp collision data at a center-of-mass energy of 7 TeV. The data were collected by the CMS detector at the LHC, and correspond to an integrated luminosity of 36 pb(-1). An excess of these events over standard model contributions is a signature of new physics such as large extra dimensions and unparticles. The number of observed events is in good agreement with the prediction of the standard model, and significant extension of the current limits on parameters of new physics benchmark models is achieved. 相似文献
43.
Given a finitely presented group and an epimorphism Cochran and Harvey defined a sequence of invariants , which can be viewed as the degrees of higher-order Alexander polynomials. Cochran and Harvey showed that (up to a minor modification) this is a never decreasing sequence of numbers if is the fundamental group of a 3-manifold with empty or toroidal boundary. Furthermore they showed that these invariants give lower bounds on the Thurston norm.
Using a certain Cohn localization and the duality of Reidemeister torsion we show that for a fundamental group of a 3-manifold any jump in the sequence is necessarily even. This answers in particular a question of Cochran. Furthermore using results of Turaev we show that under a mild extra hypothesis the parity of the Cochran-Harvey invariant agrees with the parity of the Thurston norm.
44.
Dr. Stanislav L. Veinberg Zachary W. Friedl Austin W. Lindquist Brianna Kispal Dr. Kristopher J. Harris Dr. Luke A. O'Dell Prof. Robert W. Schurko 《Chemphyschem》2016,17(23):4011-4027
14N ultra‐wideline solid‐state NMR (SSNMR) spectra were obtained for 16 naturally occurring amino acids and four related derivatives by using the WURST–CPMG (wideband, uniform rate, and smooth truncation Carr–Purcell–Meiboom–Gill) pulse sequence and frequency‐stepped techniques. The 14N quadrupolar parameters were measured for the sp3 nitrogen moieties (quadrupolar coupling constant, CQ, values ranged from 0.8 to 1.5 MHz). With the aid of plane‐wave DFT calculations of the 14N electric‐field gradient tensor parameters and orientations, the moieties were grouped into three categories according to the values of the quadrupolar asymmetry parameter, ηQ: low (≤0.3), intermediate (0.31–0.7), and high (≥0.71). For RNH3+ moieties, greater variation in N?H bond lengths was observed for systems with intermediate ηQ values than for those with low ηQ values (this variation arose from different intermolecular hydrogen‐bonding arrangements). Strategies for increasing the efficiency of 14N SSNMR spectroscopy experiments were discussed, including the use of sample deuteration, high‐power 1H decoupling, processing strategies, high magnetic fields, and broadband cross‐polarization (BRAIN‐CP). The temperature‐dependent rotations of the NH3 groups and their influence on 14N transverse relaxation rates were examined. Finally, 14N SSNMR spectroscopy was used to differentiate two polymorphs of l ‐histidine through their quadrupolar parameters and transverse relaxation time constants. The strategies outlined herein permitted the rapid acquisition of directly detected 14N SSNMR spectra that to date was not matched by other proposed methods. 相似文献
45.
Day JG Iorenz M Wilding TA Friedl T Harding K Pröschold T Brennan D Müller J Santos LM Santos MF Osório HC Amaral R Lukesova A Hrouzek P Lukes M Elster J Lukavsky J Probert I Ryan MJ Benson EE 《Cryo letters》2007,28(5):359-376
Two cryopreservation methods, colligative cryoprotection coupled with controlled cooling and vitrification-based, encapsulation-dehydration were validated by five members of the EU research infrastructure consortium, COBRA, and two independent external validators. The test strain Chlorella vulgaris SAG 211-11b was successfully cryopreserved using two-step cooling employing passive (Mr Frosty) and Controlled Rate Freezers (CRF) attaining the desired recovery target within 15% of the median viability level (94%). Significant differences (p < 0.05) between cooling regimes were observed where Mr Frosty was more variable (Inter-Quartile Range being 21.5%, versus 13.0% for CRF samples). Viability assessment using fluorescein diacetate gave significantly (P < 0.0001) higher survival than growth in agar with median values being 96% and 89%, respectively. On employing encapsulation-dehydration, greater variability between some validators was observed, with six labs observing recovery in 100% of the beads (84-95% of cells surviving) and one lab observing survival in 80% of the treated beads. Bead disruption followed by algal growth in agar was considered the most reliable and accurate method of assessing cell survival for encapsulation-dehydration. 相似文献
46.
Let f:M→N be a continuous map between closed irreducible graph manifolds with infinite fundamental group. Perron and Shalen (1999) [16] showed that if f induces a homology equivalence on all finite covers, then f is in fact homotopic to a homeomorphism. Their proof used the statement that every graph manifold is finitely covered by a 3-manifold whose fundamental group is residually p for every prime p. We will show that this statement regarding graph manifold groups is not true in general, but we will show how to modify the argument of Perron and Shalen to recover their main result. As a by-product we will determine all semidirect products Z?Zd which are residually p for every prime p. 相似文献
47.
Ashrafullah Khan Shafi Ullah Khan Adnan Khan Bushra Shal Sabih Ur Rehman Shaheed Ur Rehman Thet Thet Htar Salman Khan Sirajudheen Anwar Ahmed Alafnan Kannan RR Rengasamy 《Molecules (Basel, Switzerland)》2022,27(13)
Plants are an important source of drug development and numerous plant derived molecules have been used in clinical practice for the ailment of various diseases. The Toll-like receptor-4 (TLR-4) signaling pathway plays a crucial role in inflammation including rheumatoid arthritis. The TLR-4 binds with pro-inflammatory ligands such as lipopolysaccharide (LPS) to induce the downstream signaling mechanism such as nuclear factor κappa B (NF-κB) and mitogen activated protein kinases (MAPKs). This signaling activation leads to the onset of various diseases including inflammation. In the present study, 22 natural compounds were studied against TLR-4/AP-1 signaling, which is implicated in the inflammatory process using a computational approach. These compounds belong to various classes such as methylxanthine, sesquiterpene lactone, alkaloid, flavone glycosides, lignan, phenolic acid, etc. The compounds exhibited different binding affinities with the TLR-4, JNK, NF-κB, and AP-1 protein due to the formation of multiple hydrophilic and hydrophobic interactions. With TLR-4, rutin had the highest binding energy (−10.4 kcal/mol), poncirin had the highest binding energy (−9.4 kcal/mol) with NF-κB and JNK (−9.5 kcal/mol), respectively, and icariin had the highest binding affinity (−9.1 kcal/mol) with the AP-1 protein. The root means square deviation (RMSD), root mean square fraction (RMSF), and radius of gyration (RoG) for 150 ns were calculated using molecular dynamic simulation (MD simulation) based on rutin’s greatest binding energy with TLR-4. The RMSD, RMSF, and RoG were all within acceptable limits in the MD simulation, and the complex remained stable for 150 ns. Furthermore, these compounds were assessed for the potential toxic effect on various organs such as the liver, heart, genotoxicity, and oral maximum toxic dose. Moreover, the blood–brain barrier permeability and intestinal absorption were also predicted using SwissADME software (Lausanne, Switzerland). These compounds exhibited promising physico-chemical as well as drug-likeness properties. Consequently, these selected compounds portray promising anti-inflammatory and drug-likeness properties. 相似文献
48.
Ohne Zusammenfassung 相似文献
49.
Mag. pharm. Franz Friedl 《Monatshefte für Chemie / Chemical Monthly》1910,31(8):917-932
Ohne ZusammenfassungZum Schlusse sei es mir gestattet, meinem hochverehrten Lehrer Herrn Prof. Dr. G. Goldschmiedt für die Liebenswürdigkeit, mit der er mich bei meinen Arbeiten durch Rat und Tat unterstützte, meinen herzlichsten Dank auszusprechen. 相似文献
50.
Limitations of the optimization of the resolution by the buffer pH in capillary zone electrophoresis 总被引:1,自引:0,他引:1
The model which enables the prediction of the resolution as a function of the buffer pH for capillary zone electrophoresis described elsewhere has two main limitations. One limitation is linked to the accuracy of the data necessary for the calculation, namely actual mobilities, pK values and effective charge numbers of the separands. The other is given by the fact that only longitudinal diffusion is taken as the source of peak dispersion in the model. Examples for deviations from the predicted resolution are discussed, with wall adsorption of small ions contributing significantly to migration and distorsion.This work is dedicated to S. Hjertén on the occasion of his 65th birthday 相似文献