442 research outputs found

    In vivo extracellular matrix protein expression by human periodontal ligament after stimulation with orthodontic force

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    It is well known that the orthodontic force applied to teeth generates a series of events that remodel the periodontal ligament (PDL). Extracellular matrix proteins (ECM) are described as molecular regulators of these events. However, the exact contribution of these proteins in human PDL modeling by orthodontic force application in vivo is not known. The aim of this present study was to evaluate the protein expression of fibronectin, laminin and vitronectin by human PDL from teeth on which orthodontic force was applied. Twenty healthy individuals were included in the study. PDL was obtained from teeth after a 3-week treatment with orthodontic force. PDL-protein samples were separated on 7.5% SDS-PAGE Western blot analysis with specific monoclonal antibodies for fibronectin, laminin and vitronectin. Bands were visualized with an enhanced chemiluminescence detection system and densitometric. Scanning of bands was carried out to compare differences in protein expression. A significant increment in fibronectin (13.9%), laminin (16.5%) and vitronectin (14.2%) expression was found in PDL from teeth treated with orthodontic force for 3 weeks in comparison with teeth in the control group. Our results support the concept that molecular changes take place by application of orthodontic forces to the PDL. Over expression of these proteins suggests that extracellular matrix (ECM) remodeling could be generated in response to mechanical stress.Keywords: Extracellular matrix proteins, periodontal ligament, orthodontic forceAfrican Journal of Biotechnology Vol. 9(34), pp. 5599-5604, 23 August, 201

    First Search for Exclusive Diphoton Production at High Mass with Tagged Protons in Proton-Proton Collisions at √s = 13 TeV

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    Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC

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    The performance is presented of the reconstruction and identification algorithms for electrons and photons with the CMS experiment at the LHC. The reported results are based on proton-proton collision data collected at a center-of-mass energy of 13 TeV and recorded in 2016-2018, corresponding to an integrated luminosity of 136 fb(-1). Results obtained from lead-lead collision data collected at root S-NN = 5.02 TeV are also presented. Innovative techniques are used to reconstruct the electron and photon signals in the detector and to optimize the energy resolution. Events with electrons and photons in the final state are used to measure the energy resolution and energy scale uncertainty in the recorded events. The measured energy resolution for electrons produced in Z boson decays in proton-proton collision data ranges from 2 to 5%, depending on electron pseudorapidity and energy loss through bremsstrahlung in the detector material. The energy scale in the same range of energies is measured with an uncertainty smaller than 0.1 (0.3)% in the barrel (endcap) region in proton-proton collisions and better than 1(3)% in the barrel (endcap) region in heavy ion collisions. The timing resolution for electrons from Z boson decays with the full 2016-2018 proton-proton collision data set is measured to be 200 ps.Peer reviewe

    Erratum to: Search for dark matter produced in association with a leptonically decaying Z{\mathrm{Z}} boson in proton–proton collisions at s=13 TeV\sqrt{s}=13\,\text {Te}\text {V}

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    Search for low-mass dilepton resonances in Higgs boson decays to four-lepton final states in proton–proton collisions at s=13 TeV\sqrt{s}=13\,\text {TeV}

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    A search for low-mass dilepton resonances in Higgs boson decays is conducted in the four-lepton final state. The decay is assumed to proceed via a pair of beyond the standard model particles, or one such particle and a Z boson. The search uses proton–proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137fb−1, at a center-of-mass energy s√=13TeV. No significant deviation from the standard model expectation is observed. Upper limits at 95% confidence level are set on model-independent Higgs boson decay branching fractions. Additionally, limits on dark photon and axion-like particle production, based on two specific models, are reported

    Measurements of the differential cross sections of the production of Z + jets and Îł + jets and of Z boson emission collinear with a jet in pp collisions at s \sqrt{s} = 13 TeV

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    Measurements of the differential cross sections of Z + jets and γ + jets production, and their ratio, are presented as a function of the boson transverse momentum. Measurements are also presented of the angular distribution between the Z boson and the closest jet. The analysis is based on pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb−1 recorded by the CMS experiment at the LHC. The results, corrected for detector effects, are compared with various theoretical predictions. In general, the predictions at higher orders in perturbation theory show better agreement with the measurements. This work provides the first measurement of the ratio of the differential cross sections of Z + jets and γ + jets production at 13 TeV, as well as the first direct measurement of Z bosons emitted collinearly with a jet

    Observation of Forward Neutron Multiplicity Dependence of Dimuon Acoplanarity in Ultraperipheral Pb-Pb Collisions at sNN\sqrt{sNN} =5.02 TeV

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    The first measurement of the dependence of ÎłÎłâ†’ÎŒ+^{+} Ό−^{-} production on the multiplicity of neutrons emitted very close to the beam direction in ultraperipheral heavy ion collisions is reported. Data for lead-lead interactions at sNN\sqrt{^{s}NN}=5.02 TeV, with an integrated luminosity of approximately 1.5nb−1^{-1}, are collected using the CMS detector at the LHC. The azimuthal correlations between the two muons in the invariant mass region 88.3. The back-to-back correlation structure from leading-order photon-photon scattering is found to be significantly broader for events with a larger number of emitted neutrons from each nucleus, corresponding to interactions with a smaller impact parameter. This observation provides a data-driven demonstration that the average transverse momentum of photons emitted from relativistic heavy ions has an impact parameter dependence. These results provide new constraints on models of photon-induced interactions in ultraperipheral collisions. They also provide a baseline to search for possible final-state effects on lepton pairs caused by traversing a quark-gluon plasma produced in hadronic heavy ion collisions

    Measurement of differential cross sections for Z bosons produced in association with charm jets in pp collisions at s \sqrt{s} = 13 TeV

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    Measurements are presented of differential cross sections for the production of Z bosons in association with at least one jet initiated by a charm quark in pp collisions at s √s = 13 TeV. The data recorded by the CMS experiment at the LHC correspond to an integrated luminosity of 35.9 fb−1. The final states contain a pair of electrons or muons that are the decay products of a Z boson, and a jet consistent with being initiated by a charm quark produced in the hard interaction. Differential cross sections as a function of the transverse momentum pT of the Z boson and pT of the charm jet are compared with predictions from Monte Carlo event generators. The inclusive production cross section 405.4 ± 5.6 (stat) ± 24.3 (exp) ± 3.7 (theo) pb, is measured in a fiducial region requiring both leptons to have pseudorapidity |η| 10 GeV, at least one lepton with pT > 26 GeV, and a mass of the pair in the range 71–111 GeV, while the charm jet is required to have pT > 30 GeV and |η| < 2.4. These are the first measurements of these cross sections in proton-proton collisions at 13 TeV

    Search for the lepton flavor violating decay τ → 3ÎŒ in proton-proton collisions at s \sqrt{\mathrm{s}} = 13 TeV

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    Results are reported from a search for the lepton flavor violating decay τ → 3ÎŒ in proton-proton collisions at s \sqrt{\mathrm{s}} = 13 TeV. The data sample corresponds to an integrated luminosity of 33.2 fb−1^{-1} recorded by the CMS experiment at the LHC in 2016. The search exploits τ leptons produced in both W boson and heavy-flavor hadron decays. No significant excess above the expected background is observed. An upper limit on the branching fraction B(τ → 3ÎŒ) of 8.0 x 10−8^{-8} at 90% confidence level is obtained, with an expected upper limit of 6.9 x 10−8^{-8}
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