Structures and reactivity of peroxy radicals and dimeric products revealed by online tandem mass spectrometry

Organic peroxy radicals (RO2) play a pivotal role in the degradation of hydrocarbons. The autoxidation of atmospheric RO2 radicals produces highly oxygenated organic molecules (HOMs), including low-volatility ROOR dimers formed by bimolecular RO2 + RO2 reactions. HOMs can initiate and greatly contribute to the formation and growth of atmospheric particles. As a result, HOMs have far-reaching health and climate implications. Nevertheless, the structures and formation mechanism of RO2 radicals and HOMs remain elusive. Here, we present the in-situ characterization of RO2 and dimer structure in the gas-phase, using online tandem mass spectrometry analyses. In this study, we constrain the structures and formation pathway of several HOM-RO2 radicals and dimers produced from monoterpene ozonolysis, a prominent atmospheric oxidation process. In addition to providing insights into atmospheric HOM chemistry, this study debuts online tandem MS analyses as a unique approach for the chemical characterization of reactive compounds, e.g., organic radicals.Peer reviewe

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

Peer reviewe

Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

Peer reviewe

Search for anomalous couplings in boosted WW/WZ -> l nu q(q)over-bar production in proton-proton collisions at root s=8TeV

Peer reviewe

Search for standard model production of four top quarks in proton–proton collisions at

A search for events containing four top quarks (t¯tt¯t) is reported from proton–proton collisions recorded by the CMS experiment at √s=13TeVand corresponding to an integrated luminosity of 2.6fb−1. The analysis considers the single-lepton (e or μ)+jets and the opposite-sign dilepton (μ+μ−, μ±e∓, or e+e−)+jets channels. It uses boosted decision trees to combine information on the global event and jet properties to distinguish between t¯tt¯tand t¯tproduction. The number of events observed after all selection requirements is consistent with expectations from background and standard model signal predictions, and an upper limit is set on the cross section for t¯tt¯tproduction in the standard model of 94fb at 95% confidence level (10.2×the prediction), with an expected limit of 118fb. This is combined with the results from the published CMS search in the same-sign dilepton channel, resulting in an improved limit of 69fb at 95% confidence level (7.4×the prediction), with an expected limit of 71fb. These are the strongest constraints on the rate of t¯tt¯tproduction to date.We congratulate our colleagues in the CERN accelerator depart-ments for the excellent performance of the LHC and thank the technical and administrative staffs at CERN and at other CMS in-stitutes for their contributions to the success of the CMS effort. In addition, we gratefully acknowledge the computing centers and personnel of the Worldwide LHC Computing Grid for delivering so effectively the computing infrastructure essential to our analyses. Finally, we acknowledge the enduring support for the construc-tion and operation of the LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MOST, and NSFC (China); COLCIEN-CIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); SENESCYT (Ecuador); MoER, ERC IUT, and ERDF (Estonia); Academy of Fin-land, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH (Hun-gary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT, LNS, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS, RFBR and RAEP(Russia); MESTD (Serbia); SEIDI, CPAN, PCTI and FEDER (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEP-Center, IPST, STAR, and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie pro-gram and the European Research Council and EPLANET (Euro-pean Union); the Leventis Foundation; the A. P. Sloan Founda-tion; the Alexander von Humboldt Foundation; the Belgian Fed-eral Science Policy Office; the Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technolo-gie (IWT-Belgium); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Council of Scientific and In-dustrial Research, India; the HOMING PLUS program of the Foun-dation for Polish Science, cofinanced from European Union, Euro-pean Regional Development Fund, the Mobility Plus program of the Ministry of Science and Higher Education, the National Science Center (Poland), contracts Harmonia 2014/14/M/ST2/00428, Opus 2014/13/B/ST2/02543, 2014/15/B/ST2/03998, and 2015/19/B/ST2/02861, Sonata-bis 2012/07/E/ST2/01406; the National Priorities Re-search Program by Qatar National Research Fund; the Programa Clarín-COFUND del Principado de Asturias; the Thalis and Aris-teia programs cofinanced by EU-ESF and the Greek NSRF; the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chula-longkorn University and the Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand); and the Welch Foundation, contract C-1845

Suppression of Excited Υ States Relative to the Ground State in Pb-Pb Collisions at √sNN=5.02 TeV

The relative yields of Υ mesons produced in pp and Pb-Pb collisions at √sNN=5.02 TeV and reconstructed via the dimuon decay channel are measured using data collected by the CMS experiment. Double ratios are formed by comparing the yields of the excited states, Υ(2S) and Υ(3S), to the ground state, Υ(1S), in both Pb-Pb and pp collisions at the same center-of-mass energy. The double ratios, [Υ(nS)/Υ(1S)]Pb−Pb/[Υ(nS)/Υ(1S)]pp, are measured to be 0.308±0.055(stat)±0.019(syst) for the Υ(2S) and less than 0.26 at 95% confidence level for the Υ(3S). No significant Υ(3S) signal is found in the Pb-Pb data. The double ratios are studied as a function of collision centrality, as well as Υ transverse momentum and rapidity. No significant dependencies are observed

Insulinothérapie à la phase initiale de la transplantation rénale (effet sur le pouvoir anti-oxydant du plasma)

Hyperglycémie et ischémie-reperfusion sont 2 sources majeures de stress oxydant à la phase initiale de la transplantation rénale. Nous avons réalisé une étude prospective, randomisée, à la phase initiale de la greffe rénale en constituant 2 groupes, l'un avec contrôle de la glycémie par de l'insuline, l'autre sans contrôle. L'effet sur le pouvoir anti-oxydant du plasma (TRAP) a été mesuré pendant les 15 jours qui suivent la greffe ainsi que le malondialdéhyde urinaire (MDAu). Le TRAP est significativement abaissé dans la population générale dans les 3 premiers jours post-greffe, puis remonte. Les patients sous insuline ont un maintient de leur TRAP au long de l'étude. Il n'y a pas de corrélation avec l'équilibre glycémique. Le MDA s'élève le 9ème jour. La mesure de la fonction rénale est similaire dans les 2 groupes à 6 mois. Notre étude est la première à montrer un maintient du TRAP sous insuline à la phase initiale de la greffe rénaleAMIENS-BU Santé (800212102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF