359 research outputs found
Synthesis and Biological Evaluation of some Novel 2-Mercaptobenzothiazoles Carrying 1,3,4-Oxadiazole, 1,3,4-Thiadiazole and 1,2,4-Triazole Moieties
Several 2-mercaptobenzothiazole derivatives containing 1,3,4-oxadiazoles, 1,2,4-triazoles and 1,3,4-thiadiazoles at the second position were synthesized. Some of these synthesized compounds were evaluated for their in vivo analgesic, anti-inflammatory, acute toxicity and ulcerogenic actions. Some of the tested compounds showed significant analgesic and anti-inflammatory activities. Two of the compounds showed significant gastrointestinal protection compared to the standard drug diclofenac sodium. The compounds were also tested for their in vitro antimicrobial activity with most displaying selective activity against the Gram-negative bacteria Pseudomonas aeruginosa. In the present investigation the tested compounds did not possess antifungal activity.Keywords: 2-Mercaptobenzothiazoles, 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, Antimicrobial Activity, Anti-inflammatory Activit
Differential Effect of Contrast Polarity Reversals in Closed Squares and Open L-Junctions
Scene segmentation depends on interaction between geometrical and photometric factors. It has been shown that reversals in contrast polarity at points of highest orientation discontinuity along closed contours significantly impair shape discrimination performance, while changes in contrast polarity at straight(er) contour segments do not have such deleterious effects (Spehar, 2002). Here we employ (semi) high resolution fMRI (1.5âmmâĂâ1.5âmmâĂâ1.5âmm) to investigate the neuronal substrate underlying these perception effects. Stimuli consisted of simple elements (a) squares with contrast reversals along straight segments; (b) squares with contrast reversals in the corner (highest orientation discontinuity); (c) L-Junctions with contrast reversals along the straight ends; (d) L-Junctions with contrast reversals in the corner. Element with contrast polarity reversals are easy to distinguish though appear geometrically equivalent. For squares with contrast polarity reversals only along straight lines we find significantly lower BOLD modulation compared to any of the control conditions, which show similar responses to each other. In the light of previous psychophysical work (Elder and Zucker, 1993; Spehar, 2002) we speculate that this effect is due to closure perception. We observe this across a wide range of areas on occipital cortex
Study of the B +â J / Ï Î ÂŻ p decay in proton-proton collisions at âs = 8 TeV
A study of the B +â J / Ï Î ÂŻ p decay using proton-proton collision data collected at s = 8 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.6 fbâ1, is presented. The ratio of branching fractions B(B+âJ/ÏÎÂŻp)/B(B+âJ/ÏKâ(892)+) is measured to be (1.054 ± 0.057(stat) ± 0.035(syst) ± 0.011(B))%, where the last uncertainty reflects the uncertainties in the world-average branching fractions of Î ÂŻ and K*(892) + decays to reconstructed final states. The invariant mass distributions of the J / Ï Î ÂŻ , J/Ïp, and Î ÂŻ p systems produced in the B +â J / Ï ÎÂŻ p decay are investigated and found to be inconsistent with the pure phase space hypothesis. The analysis is extended by using a model-independent angular amplitude analysis, which shows that the observed invariant mass distributions are consistent with the contributions from excited kaons decaying to the Î ÂŻ p system. [Figure not available: see fulltext.
Search for new neutral Higgs bosons through the H â ZAâ â+ââb b ÂŻ process in pp collisions at âs = 13 TeV
This paper reports on a search for an extension to the scalar sector of the standard model, where a new CP-even (odd) boson decays to a Z boson and a lighter CP-odd (even) boson, and the latter further decays to a b quark pair. The Z boson is reconstructed via its decays to electron or muon pairs. The analysed data were recorded in proton-proton collisions at a center-of-mass energy s = 13 TeV, collected by the CMS experiment at the LHC during 2016, corresponding to an integrated luminosity of 35.9 fbâ1. Data and predictions from the standard model are in agreement within the uncertainties. Upper limits at 95% confidence level are set on the production cross section times branching fraction, with masses of the new bosons up to 1000 GeV. The results are interpreted in the context of the two-Higgs-doublet model. [Figure not available: see fulltext.]
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Measurement of the top quark Yukawa coupling from t t kinematic distributions in the lepton+jets final state in proton-proton collisions at s =13 TeV MEASUREMENT of the TOP QUARK YUKAWA COUPLING from ... SIRUNYAN et al.
Results are presented for an extraction of the top quark Yukawa coupling from top quark-antiquark (tt) kinematic distributions in the lepton plus jets final state in proton-proton collisions, based on data collected by the CMS experiment at the LHC at s=13 TeV, corresponding to an integrated luminosity of 35.8 fb-1. Corrections from weak boson exchange, including Higgs bosons, between the top quarks can produce large distortions of differential distributions near the energy threshold of tt production. Therefore, precise measurements of these distributions are sensitive to the Yukawa coupling. Top quark events are reconstructed with at least three jets in the final state, and a novel technique is introduced to reconstruct the tt system for events with one missing jet. This technique enhances the experimental sensitivity in the low invariant mass region, Mtt. The data yields in Mtt, the rapidity difference |yt-yt|, and the number of reconstructed jets are compared with distributions representing different Yukawa couplings. These comparisons are used to measure the ratio of the top quark Yukawa coupling to its standard model predicted value to be 1.07-0.43+0.34 with an upper limit of 1.67 at the 95% confidence level
Search for a heavy Higgs boson decaying to a pair of W bosons in proton-proton collisions at âs = 13 TeV
A search for a heavy Higgs boson in the mass range from 0.2 to 3.0 TeV, decaying to a pair of W bosons, is presented. The analysis is based on proton-proton collisions at s = 13 TeV recorded by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of 35.9 fbâ1. The W boson pair decays are reconstructed in the 2â2Îœ and âÎœ2q final states (with â = e or ÎŒ). Both gluon fusion and vector boson fusion production of the signal are considered. Interference effects between the signal and background are also taken into account. The observed data are consistent with the standard model (SM) expectation. Combined upper limits at 95% confidence level on the product of the cross section and branching fraction exclude a heavy Higgs boson with SM-like couplings and decays up to 1870 GeV. Exclusion limits are also set in the context of a number of two-Higgs-doublet model formulations, further reducing the allowed parameter space for SM extensions. [Figure not available: see fulltext.
Running of the top quark mass from proton-proton collisions at \sqrt{s} = 13 TeV
The running of the top quark mass is experimentally investigated for the first time. The mass of the top quark in the modified minimal subtraction \bar{MS} renormalization scheme is extracted from a comparison of the differential top quark-antiquark (t\bar{t}) cross section as a function of the invariant mass of the (t\bar{t}) system to next-to-leading-order theoretical predictions. The differential cross section is determined at the parton level by means of a maximum-likelihood fit to distributions of final-state observables. The analysis is performed using (t\bar{t}) candidate events in the e^{±} ÎŒ^{â} channel in proton-proton collision data at a centre-of-mass energy of 13âŻTeV recorded by the CMS detector at the CERN LHC in 2016, corresponding to an integrated luminosity of 35.9 fb^{-1}. The extracted running is found to be compatible with the scale dependence predicted by the corresponding renormalization group equation. In this analysis, the running is probed up to a scale of the order of 1âŻTeV
Search for dijet resonances using events with three jets in proton-proton collisions at \sqrt{s} = 13 TeV
A search for a narrow resonance with a mass between 350 and 700 GeV, and decaying into a pair of jets, is performed using proton-proton collision events containing at least three jets. The data sample corresponds to an integrated luminosity of 18.3 fb^{â1} recorded at \sqrt{s} = 13 TeV with the CMS detector. Data are collected with a technique known as âdata scoutingâ, in which the events are reconstructed, selected, and recorded at a high rate in a compact form by the high-level trigger. The three-jet final state provides sensitivity to lower resonance masses than in previous searches using the data scouting technique. The spectrum of the dijet invariant mass, calculated from the two jets with the largest transverse momenta in the event, is used to search for a resonance. No significant excess over a smoothly falling background is found. Limits at 95% confidence level are set on the production cross section of a narrow dijet resonance and compared with the cross section of a vector dark matter mediator coupling to dark matter particles and quarks. Translating to a model where the narrow resonance interacts only with quarks, upper limits on this coupling range between 0.10 and 0.15, depending on the resonance mass. These results represent the most stringent upper limits in the mass range between 350 and 450 GeV obtained with a flavor-inclusive dijet resonance search
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