Substituent effects on the genotoxicity of 4-nitrostilbene derivatives

4-Nitrostilbene and twelve of its derivatives (eleven E-stilbenes and two Z-stilbenes) were examined for possible quantitative structure-activity relationships of their in vitro and in vivo genotoxicity. Relative mutagenicity was studied with and without S9 activation in Salmonella strains TA98 and TA100, as well as in the nitroreductase deficient strains TA98/NR and TA100/NR. Chromosomal aberrations in the bone-marrow cells of mice following intraperitoneal administration of the nitrostilbenes were observed as an indicator of in vivo genotoxicity. All of the compounds were active in TA98 and TA100 without S9 activation, with the exception of 4-amino-4'-nitrostilbene in TA100. Mutagenic activity was greatly reduced or eliminated in the NR strains, which is consistent with metabolic activation of the compounds by bacterial reductase. The presence of S9 lowered the activity of most of the nitrostilbenes presumedly by enzymatic detoxication. Hammet values of substituents, partition coefficients and frontier orbital energies (ELUMO and EHOMO) were studied for correlations with mutagenicity of the eleven E-stilbenes. Correlations could be established between mutagenicity in TA98 without S9 activation and the Hammet values. The same mutagenicity could also be correlated to ELUMO. Rationales for these correlations include the concept that electron-withdrawing groups which lower ELUMO should facilitate the reduction of the nitro group, leading to the proximate mutagen hydroxylamine. The correlations are also explained by the concept that electron-withdrawing groups should help stabilize the hydroxylamine intermediate and make the ultimate mutagenic species, the nitrenium ions, more reactive toward DNA. The relationship between mutagenicity and electronic effects of substituent groups found in vitro could not be extended to the in vivo results. However, except for the dinitrostilbenes, where insolubility prevented their testing, all the nitrostilbenes produced a statistically significant increase in chromosomal aberrations compared to the negative solvent control.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31200/1/0000102.pd

Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV

Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities.Comment: Submitted to Physics Letters

Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

Peer reviewe

Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

Peer reviewe

Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

Peer reviewe

Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search

Peer reviewe

Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

Peer reviewe

Measurement of the Z boson differential cross section in transverse momentum and rapidity in proton-proton collisions at 8 TeV

We present a measurement of the Z boson differential cross section in rapidity and transverse momentum using a data sample of pp collision events at a centre-of-mass energy s=8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The Z boson is identified via its decay to a pair of muons. The measurement provides a precision test of quantum chromodynamics over a large region of phase space. In addition, due to the small experimental uncertainties in the measurement the data has the potential to constrain the gluon parton distribution function in the kinematic regime important for Higgs boson production via gluon fusion. The results agree with the next-to-next-to-leading-order predictions computed with the fewz program. The results are also compared to the commonly used leading-order MadGraph and next-to-leading-order powheg generators. © 2015 CERN for the benefit of the CMS Collaboration

Search for neutral resonances decaying into a Z boson and a pair of b jets or τ leptons

A search is performed for a new resonance decaying into a lighter resonance and a Z boson. Two channels are studied, targeting the decay of the lighter resonance into either a pair of oppositely charged τ leptons or a bb‾ pair. The Z boson is identified via its decays to electrons or muons. The search exploits data collected by the CMS experiment at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.8 fb −1 . No significant deviations are observed from the standard model expectation and limits are set on production cross sections and parameters of two-Higgs-doublet models

Search for a low-mass pseudoscalar Higgs boson produced in association with a bb⁻ pair in pp collisions at √s=8 TeV

A search is reported for a light pseudoscalar Higgs boson decaying to a pair of tau leptons, produced in association with a b (b) over bar pair, in the context of two-Higgs-doublet models. The results are based on pp collision data at a centre-of-mass energy of 8 TeV collected by the CMS experiment at the LHC and corresponding to an integrated luminosity of 19.7 fb(-1). Pseudoscalar boson masses between 25 and 80 GeV are probed. No evidence for a pseudoscalar boson is found and upper limits are set on the product of cross section and branching fraction to tau pairs between 7 and 39 pb at the 95% confidence level. This excludes pseudoscalar A bosons with masses between 25 and 80 GeV, with SM-like Higgs boson negative couplings to down-type fermions, produced in association with bb pairs, in Type II, two-Higgs-doublet models. (C) 2016 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommonnorg/licensesiby/4.01)