Displaying publications 1 - 20 of 93 in total

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  1. Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV
    CMS Collaboration, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Eur Phys J C Part Fields, 2014 09 26;74(9):3036.
    PMID: 25814912
    Searches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety of signatures with leptons and [Formula: see text], [Formula: see text], and Higgs bosons are presented. Results are based on a sample of proton-proton collision data collected at center-of-mass energy [Formula: see text] with the CMS detector in 2012, corresponding to an integrated luminosity of 19.5 [Formula: see text]. The observed event rates are in agreement with expectations from the standard model. These results probe charginos and neutralinos with masses up to 720 [Formula: see text], and sleptons up to 260 [Formula: see text], depending on the model details.
  2. Measurement of top quark-antiquark pair production in association with a W or Z boson in pp collisions at [Formula: see text][Formula: see text]
    CMS Collaboration, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Eur Phys J C Part Fields, 2014 09 17;74(9):3060.
    PMID: 25814914
    A measurement of the cross section for the production of top quark-antiquark pairs ([Formula: see text]) in association with a vector boson V (W or Z) in proton-proton collisions at [Formula: see text][Formula: see text] is presented. The results are based on a dataset corresponding to an integrated luminosity of 19.5 fb[Formula: see text] recorded with the CMS detector at the LHC. The measurement is performed in three leptonic (e and [Formula: see text]) channels: a same-sign dilepton analysis targeting [Formula: see text] events, and trilepton and four-lepton analyses designed for [Formula: see text] events. In the same-sign dilepton channel, the [Formula: see text] cross section is measured as [Formula: see text], corresponding to a significance of 1.6 standard deviations over the background-only hypothesis. Combining the trilepton and four-lepton channels, a direct measurement of the [Formula: see text] cross section, [Formula: see text], is obtained with a significance of 3.1 standard deviations. The measured cross sections are compatible with standard model predictions within their experimental uncertainties. The inclusive [Formula: see text] process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels.
  3. Measurement of WZ and ZZ production in pp collisions at [Formula: see text] in final states with b-tagged jets
    CMS Collaboration, Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, et al.
    Eur Phys J C Part Fields, 2014 08 07;74(8):2973.
    PMID: 25814904
    Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at [Formula: see text][Formula: see text] in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either [Formula: see text], [Formula: see text] or [Formula: see text], [Formula: see text], or [Formula: see text]). The results are based on data corresponding to an integrated luminosity of 18.9 fb[Formula: see text] collected with the CMS detector at the Large Hadron Collider. The measured cross sections, [Formula: see text] and [Formula: see text], are consistent with next-to-leading order quantum chromodynamics calculations.
  4. Measurement of jet multiplicity distributions in [Formula: see text] production in pp collisions at [Formula: see text]
    CMS Collaboration, Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, et al.
    Eur Phys J C Part Fields, 2014 08 20;74(8):3014.
    PMID: 25814909
    The normalised differential top quark-antiquark production cross section is measured as a function of the jet multiplicity in proton-proton collisions at a centre-of-mass energy of 7[Formula: see text] at the LHC with the CMS detector. The measurement is performed in both the dilepton and lepton+jets decay channels using data corresponding to an integrated luminosity of 5.0[Formula: see text]. Using a procedure to associate jets to decay products of the top quarks, the differential cross section of the [Formula: see text] production is determined as a function of the additional jet multiplicity in the lepton+jets channel. Furthermore, the fraction of events with no additional jets is measured in the dilepton channel, as a function of the threshold on the jet transverse momentum. The measurements are compared with predictions from perturbative quantum chromodynamics and no significant deviations are observed.
  5. Measurement of differential cross sections for the production of a pair of isolated photons in pp collisions at [Formula: see text]
    CMS Collaboration, Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, et al.
    Eur Phys J C Part Fields, 2014 11 12;74(11):3129.
    PMID: 25814874
    A measurement of differential cross sections for the production of a pair of isolated photons in proton-proton collisions at [Formula: see text] is presented. The data sample corresponds to an integrated luminosity of 5.0[Formula: see text] collected with the CMS detector. A data-driven isolation template method is used to extract the prompt diphoton yield. The measured cross section for two isolated photons, with transverse energy above 40 and 25[Formula: see text] respectively, in the pseudorapidity range [Formula: see text], [Formula: see text] and with an angular separation [Formula: see text], is [Formula: see text][Formula: see text]. Differential cross sections are measured as a function of the diphoton invariant mass, the diphoton transverse momentum, the azimuthal angle difference between the two photons, and the cosine of the polar angle in the Collins-Soper reference frame of the diphoton system. The results are compared to theoretical predictions at leading, next-to-leading, and next-to-next-to-leading order in quantum chromodynamics.
  6. Fulltext Search for heavy neutrinos and [Formula: see text] bosons with right-handed couplings in proton-proton collisions at [Formula: see text]
    CMS Collaboration, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Eur Phys J C Part Fields, 2014;74(11):3149.
    PMID: 25814876 DOI: 10.1140/epjc/s10052-014-3149-z
    A search for heavy, right-handed neutrinos, [Formula: see text] ([Formula: see text]), and right-handed [Formula: see text] bosons, which arise in the left-right symmetric extensions of the standard model, has been performed by the CMS experiment. The search was based on a sample of two lepton plus two jet events collected in proton-proton collisions at a center-of-mass energy of 8[Formula: see text] corresponding to an integrated luminosity of 19.7 [Formula: see text]. For models with strict left-right symmetry, and assuming only one [Formula: see text] flavor contributes significantly to the [Formula: see text] decay width, the region in the two-dimensional [Formula: see text] mass plane excluded at a 95 % confidence level extends to approximately [Formula: see text] and covers a large range of neutrino masses below the [Formula: see text] boson mass, depending on the value of [Formula: see text]. This search significantly extends the [Formula: see text] exclusion region beyond previous results.
  7. Search for top squark and Higgsino production using diphoton Higgs boson decays
    Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Phys Rev Lett, 2014 Apr 25;112(16):161802.
    PMID: 24815637
    Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top quark (the top squark) and the Higgs boson (Higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7  fb-1 of proton-proton collision data at s=8  TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the top squark mass below 360 to 410 GeV, depending on the Higgsino mass.
  8. Search for invisible decays of Higgs bosons in the vector boson fusion and associated ZH production modes
    Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Eur Phys J C Part Fields, 2014;74(8):2980.
    PMID: 25814906
    A search for invisible decays of Higgs bosons is performed using the vector boson fusion and associated ZH production modes. In the ZH mode, the Z boson is required to decay to a pair of charged leptons or a [Formula: see text] quark pair. The searches use the 8 [Formula: see text] pp collision dataset collected by the CMS detector at the LHC, corresponding to an integrated luminosity of up to 19.7 [Formula: see text]. Certain channels include data from 7 [Formula: see text] collisions corresponding to an integrated luminosity of 4.9 [Formula: see text]. The searches are sensitive to non-standard-model invisible decays of the recently observed Higgs boson, as well as additional Higgs bosons with similar production modes and large invisible branching fractions. In all channels, the observed data are consistent with the expected standard model backgrounds. Limits are set on the production cross section times invisible branching fraction, as a function of the Higgs boson mass, for the vector boson fusion and ZH production modes. By combining all channels, and assuming standard model Higgs boson cross sections and acceptances, the observed (expected) upper limit on the invisible branching fraction at [Formula: see text] [Formula: see text] is found to be 0.58 (0.44) at 95 % confidence level. We interpret this limit in terms of a Higgs-portal model of dark matter interactions.
  9. Fulltext Advances and challenges in regenerative dentistry: A systematic review of calcium phosphate and silicate-based materials on human dental pulp stem cells
    Christie B, Musri N, Djustiana N, Takarini V, Tuygunov N, Zakaria MN, et al.
    Mater Today Bio, 2023 Dec;23:100815.
    PMID: 37779917 DOI: 10.1016/j.mtbio.2023.100815
    Conventional dentistry faces limitations in preserving tooth health due to the finite lifespan of restorative materials. Regenerative dentistry, utilizing stem cells and bioactive materials, offers a promising approach for regenerating dental tissues. Human dental pulp stem cells (hDPSCs) and bioactive materials like calcium phosphate (CaP) and silicate-based materials have shown potential for dental tissue regeneration. This systematic review aims to investigate the effects of CaP and silicate-based materials on hDPSCs through in vitro studies published since 2015. Following the PRISMA guidelines, a comprehensive search strategy was implemented in PubMed MedLine, Cochrane, and ScienceDirect databases. Eligibility criteria were established using the PICOS scheme. Data extraction and risk of bias (RoB) assessment were conducted, with the included studies assessed for bias using the Office of Health and Translation (OHAT) RoB tool. The research has been registered at OSF Registries. Ten in vitro studies met the eligibility criteria out of 1088 initial studies. Methodological heterogeneity and the use of self-synthesized biomaterials with limited generalizability were observed in the included study. The findings highlight the positive effect of CaP and silicate-based materials on hDPSCs viability, adhesion, migration, proliferation, and differentiation. While the overall RoB assessment indicated satisfactory credibility of the reviewed studies, the limited number of studies and methodological heterogeneity pose challenges for quantitative research. In conclusion, this systematic review provides valuable insights into the effects of CaP and silicate-based materials on hDPSCs. Further research is awaited to enhance our understanding and optimize regenerative dental treatments using bioactive materials and hDPSCs, which promise to improve patient outcomes.
  10. Screening of dental staff nurses for noise induced hearing loss
    Daud MK, Noh NF, Sidek DS, Abd Rahman N, Abd Rani N, Zakaria MN
    B-ENT, 2011;7(4):245-9.
    PMID: 22338236
    The effect of noise on employees of dental clinics is debatable. The purposes of this study were to determine the intensity and frequency components of dental instruments used by dental staff nurses and the prevalence of noise induced hearing loss.
  11. Morphological characteristics and pathogenicity of fungi associated with Roselle (Hibiscus Sabdariffa) diseases in Penang, Malaysia
    Eslaminejad T, Zakaria M
    Microb Pathog, 2011 Nov;51(5):325-37.
    PMID: 21839160 DOI: 10.1016/j.micpath.2011.07.007
    Roselle, or Jamaica sorrel (Hibiscus sabdariffa) is a popular vegetable in many tropical regions, cultivated for its leaves, seeds, stems and calyces which, the dried calyces are used to prepare tea, syrup, jams and jellies and as beverages. The main objectives of this study were to identify and characterise fungal pathogens associated with Roselle diseases based on their morphological and cultural characteristics and to determine the pathogenicity of four fungi infecting Roselle seedlings, namely Phoma exigua, Fusarium nygamai, Fusarium tgcq and Rhizoctonia solani in Penang. A total of 200 fungal isolates were obtained from 90 samples of symptomatic Roselle tissues. The isolates were identified based on cultural and morphological characteristics, as well as their pathogenicity. The fungal pathogen most frequently isolated was P. exigua (present in 45% of the samples), followed by F. nygamai (25%), Rhizoctonia solani (19%) and F. camptoceras (11%). Pathogenicity tests showed that P. exigua, F. nygamai, F. camptoceras and R. solani were able to infect both wounded and unwounded seedlings with different degrees of severity as indicated by the Disease severity (DS). R. solani was the most pathogenic fungus affecting both wounded and unwounded Roselle seedlings, followed by P. exigua that was highly pathogenic on wounded seedlings. F. nygamai was less pathogenic while the least pathogenic fungus was F. camptoceras, infecting only the unwounded seedlings but, surprisingly, not the wounded plants.
  12. WITHDRAWN: Corrigendum to "Morphological characteristics and pathogenicity of fungi associated with Roselle (Hibiscus Sabdariffa) diseases in Penang, Malaysia" [Microb Pathog (2011) 325-337]
    Eslaminejad T, Zakaria M
    Microb Pathog, 2012 Jun 02.
    PMID: 23063498 DOI: 10.1016/j.micpath.2012.05.009
    The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.micpath.2012.05.010;. The duplicate article has therefore been withdrawn.
  13. Associated Factors of In-hospital Mortality among Intubated Older Adults in Emergency Department; a Cross-sectional Study
    Idzwan Zakaria M, Che Manshor N, Maw Pin T
    Arch Acad Emerg Med, 2023;11(1):e16.
    PMID: 36743703 DOI: 10.22037/aaem.v11i1.1613
    INTRODUCTION: A decision-making guideline on when to intubate an older person based on predictors of intubation outcome would be extremely beneficial. This study aimed to identify the associated factors that could predict the outcomes of endotracheal intubation among older adults in the Emergency Department (ED).

    METHODS: In this retrospective cross-sectional study, patients aged ≥65 years intubated at the ED of University of Malaya Medical Centre, Kuala Lumpur, Malaysia, from 2015 to 2019 were studied. The association between age, gender, place of inhabitation, Identification of Seniors at Risk (ISAR) score for frailty, Charlson Comorbidity Index (CCI), Acute Physiology and Chronic Health Evaluation-II (APACHE-II) score, indication for intubation, and diagnosis on admission with in-hospital mortality (primary outcome) and duration of ventilation, and length of stay (secondary outcomes) were evaluated using univariate analysis and Cox's regression survival analysis.

    RESULTS: 889 cases aged 65 years and above were studied (61.5% male). The rate of in-hospital mortality was 71.4%. There was a significant association between age (p < 0.001), nursing home residency (p = 0.008), CCI≥ 5 (p = 0.001), APACHE-II (p < 0.001), pre-intubation Glasgow Coma Scale (GCS) (p < 0.001), cardiac arrest as indication of intubation (p < 0.001), diagnosis on admission (p < 0.001), length of stay (p < 0.001), and length of ventilation (p = 0.003) and in-hospital mortality. Age ≥ 85 years (HR= 1.270; 95%CI=1.074 to 1.502) and 75 to 84 years (HR=1.642; 95%CI=1.167 to 2.076), cardiac arrest as indication of intubation (HR: 1.882; 95% CI: 1.554 - 2.279), and APACHE-II scores 25 - 34 (HR: 1.423; 95% CI: 1.171 - 1.730) and ≥ 35 (HR: 1.789; 95%CI: 1.418 - 2.256) were amongst the independent predictive factors of in-hospital mortality.

    CONCLUSION: Nearly three out of four individuals aged ≥65 years intubated at the ED died during the same admission. Older age, cardiac arrest as indication of intubation, and APACHE-II score were independent predictors of in-hospital mortality.

  14. Search for displaced supersymmetry in events with an electron and a muon with large impact parameters
    Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2015 Feb 13;114(6):061801.
    PMID: 25723204
    A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at √[s]=8  TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7  fb(-1). Events are selected with an electron and muon with opposite charges that both have transverse impact parameter values between 0.02 and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e-μ final states. Limits are set on the "displaced supersymmetry" model, with pair production of top squarks decaying into an e-μ final state via R-parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to cτ=2  cm, excluding masses below 790 GeV at 95% confidence level.
  15. Study of vector boson scattering and search for new physics in events with two same-sign leptons and two jets
    Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2015 Feb 6;114(5):051801.
    PMID: 25699433
    A study of vector boson scattering in pp collisions at a center-of-mass energy of 8 TeV is presented. The data sample corresponds to an integrated luminosity of 19.4  fb(-1) collected with the CMS detector. Candidate events are selected with exactly two leptons of the same charge, two jets with large rapidity separation and high dijet mass, and moderate missing transverse energy. The signal region is expected to be dominated by electroweak same-sign W-boson pair production. The observation agrees with the standard model prediction. The observed significance is 2.0 standard deviations, where a significance of 3.1 standard deviations is expected based on the standard model. Cross section measurements for W(±)W(±) and WZ processes in the fiducial region are reported. Bounds on the structure of quartic vector-boson interactions are given in the framework of dimension-eight effective field theory operators, as well as limits on the production of doubly charged Higgs bosons.
  16. Search for Narrow Resonances Decaying to Dijets in Proton-Proton Collisions at sqrt[s]=13  TeV
    Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2016 Feb 19;116(7):071801.
    PMID: 26943527 DOI: 10.1103/PhysRevLett.116.071801
    A search for narrow resonances in proton-proton collisions at sqrt[s]=13  TeV is presented. The invariant mass distribution of the two leading jets is measured with the CMS detector using a data set corresponding to an integrated luminosity of 2.4  fb^{-1}. The highest observed dijet mass is 6.1 TeV. The distribution is smooth and no evidence for resonant particles is observed. Upper limits at 95% confidence level are set on the production cross section for narrow resonances with masses above 1.5 TeV. When interpreted in the context of specific models, the limits exclude string resonances with masses below 7.0 TeV, scalar diquarks below 6.0 TeV, axigluons and colorons below 5.1 TeV, excited quarks below 5.0 TeV, color-octet scalars below 3.1 TeV, and W^{'} bosons below 2.6 TeV. These results significantly extend previously published limits.
  17. Study of B Meson Production in p+Pb Collisions at √[S(NN)]=5.02 TeV Using Exclusive Hadronic Decays
    Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2016 Jan 22;116(3):032301.
    PMID: 26849587 DOI: 10.1103/PhysRevLett.116.032301
    The production cross sections of the B^{+}, B^{0}, and B_{s}^{0} mesons, and of their charge conjugates, are measured via exclusive hadronic decays in p+Pb collisions at the center-of-mass energy sqrt[s_{NN}]=5.02  TeV with the CMS detector at the CERN LHC. The data set used for this analysis corresponds to an integrated luminosity of 34.6  nb^{-1}. The production cross sections are measured in the transverse momentum range between 10 and 60  GeV/c. No significant modification is observed compared to proton-proton perturbative QCD calculations scaled by the number of incoherent nucleon-nucleon collisions. These results provide a baseline for the study of in-medium b quark energy loss in Pb+Pb collisions.
  18. Search for monotop signatures in proton-proton collisions at √s=8  TeV
    Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2015 Mar 13;114(10):101801.
    PMID: 25815923
    Results are presented from a search for new decaying massive particles whose presence is inferred from an imbalance in transverse momentum and which are produced in association with a single top quark that decays into a bottom quark and two light quarks. The measurement is performed using 19.7  fb^{-1} of data from proton-proton collisions at a center-of-mass energy of 8 TeV, collected with the CMS detector at the CERN LHC. No deviations from the standard model predictions are observed and lower limits are set on the masses of new invisible bosons. In particular, scalar and vector particles, with masses below 330 and 650 GeV, respectively, are excluded at 95% confidence level, thereby substantially extending a previous limit published by the CDF Collaboration.
  19. Fulltext Observation of Charge-Dependent Azimuthal Correlations in p-Pb Collisions and Its Implication for the Search for the Chiral Magnetic Effect
    Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2017 Mar 24;118(12):122301.
    PMID: 28388204 DOI: 10.1103/PhysRevLett.118.122301
    Charge-dependent azimuthal particle correlations with respect to the second-order event plane in p-Pb and PbPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV have been studied with the CMS experiment at the LHC. The measurement is performed with a three-particle correlation technique, using two particles with the same or opposite charge within the pseudorapidity range |η|<2.4, and a third particle measured in the hadron forward calorimeters (4.4
  20. Fulltext Measurement of inclusive jet production and nuclear modifications in pPb collisions at [Formula: see text]
    Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, et al.
    Eur Phys J C Part Fields, 2016;76(7):372.
    PMID: 28280445 DOI: 10.1140/epjc/s10052-016-4205-7
    Inclusive jet production in pPb collisions at a nucleon-nucleon (NN) center-of-mass energy of [Formula: see text] is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 30.1 nb[Formula: see text] is analyzed. The jet transverse momentum spectra are studied in seven pseudorapidity intervals covering the range [Formula: see text] in the NN center-of-mass frame. The jet production yields at forward and backward pseudorapidity are compared and no significant asymmetry about [Formula: see text] is observed in the measured kinematic range. The measurements in the pPb system are compared to reference jet spectra obtained by extrapolation from previous measurements in pp collisions at [Formula: see text]. In all pseudorapidity ranges, nuclear modifications in inclusive jet production are found to be small, as predicted by next-to-leading order perturbative QCD calculations that incorporate nuclear effects in the parton distribution functions.
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