515 research outputs found

    Search for supersymmetry in events with two leptons including a tau

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    Searches for new physics in events with hadronic jets, missing transverse energy, and two leptons of which at least one is a hadronically decaying tau are presented. The result is based on a data sample corresponding to an integrated luminosity of 1 \fbi at a center-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. No significant excess with respect to the standard model predictions is found.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 3 pages, 1 figur

    Flexural Strength of Preheated Resin Composites and Bonding Properties to Glass-Ceramic and Dentin

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    To test the impact of preheating (25, 37, 54, or 68 degrees C) of TetricEvoCeram (TEC), FiltekSupremeXT (FSXT), and Venus (V) on flexural strength (FS), shear bond strength (SBS) and interfacial tension (IFT). FS was tested with TEC and FSXT. For SBS, glass-ceramic and human dentin substrate were fabricated and luted with the preheated resin composite (RC). SBSs of 1500 thermal cycled specimens were measured. For IFT, glass slides covered with the non-polymerized RC were prepared and contact angles were measured. Data were analyzed using 2/1-way ANOVA with Scheffe-test, and t-test (p < 0.05). Preheated TEC (37-68 degrees C) showed higher FS compared to the control-group (25 degrees C) (p < 0.001). FSXT presented higher FS than TEC (p < 0.001). For SBS to dentin higher values for FSXT than TEC were found. The preheating temperature showed no impact on SBS to dentin. SBS to glass-ceramic revealed a positive influence of temperature for TEC 25-68 degrees C (p = 0.015). TEC showed higher values than V and FSXT (p < 0.001). IFT values increased with the preheating temperature. A significant difference could be observed in every RC group between 25 and 68 degrees C (p < 0.001)

    Impact of different pretreatments and aging procedures on the flexural strength and phase structure of zirconia ceramics

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    OBJECTIVE To test the impact of zirconia pretreatment and aging on flexural strength and phase structure. METHODS For flexural strength measurements, 180 3Y-TZP0.25_{0.25} specimens were fabricated and pretreated: (i) air-abraded (105-ÎŒm alumina, 0.25MPa), (ii) air-abraded (50-ÎŒm alumina, 0.25MPa), (iii) air-abraded (30-ÎŒm silica-coated alumina, 0.28MPa) (iv) non-pretreated. Each pretreated group (n=15) was aged: (a) hydrothermal (134°C, 0.23MPa, 2h) (b) in a mastication simulator (1,200,000×, 5/55°C) and (c) not aged. The fractured specimens were stored dry for 5 years (23°C) for analysis of phase transformation. Additionally, specimens were fabricated from 3Y-TZP0.25_{0.25} (n=12) and 3Y-TZP0.05_{0.05} (n=8), pretreated (i, ii, iii, iv), and hydrothermally aged. Each air-abrasion method was alternated using 0.05, 0.25 and 0.4MPa pressure. The phase transformation was examined by Raman spectroscopy and surface topography by scanning electron microscope. Data were analyzed using univariate ANOVA with the ScheffĂ© post hoc test and partial-eta-squared (ƞp_{p}ÂČ) (α=0.05). RESULTS The highest impact on flexural strength was exerted by the pretreatment (ηP_{P}ÂČ=0.261, p<0.001), followed by interactions between pretreatment and aging (ηP_{P}ÂČ=0.077, p=0.033). Non-pretreated and non-aged specimens showed the lowest monoclinic percentage. Hydrothermal aging and 5 years of storage at room temperature increased the monolithic percentage of 3Y-TZP0.25_{0.25}. The highest phase transformation was observed in groups air-abraded with 105-ÎŒm alumina particles. Increasing pressure during the air-abrading process increased the content of the monoclinic phase in zirconia surfaces. SIGNIFICANCE Air-abrasion with 30-ÎŒm silica-coated alumina powder can be recommended for pretreatment of 3Y-TZP0.25_{0.25} and 3Y-TZP0.05_{0.05}. For air-abrasion using alumina powder lower pressure should be used

    A pattern of care analysis: Prosthetic rehabilitation of head and neck cancer patients after radiotherapy

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    Background While some medical associations provide guidelines for the implant‐prosthetic rehabilitation of head and neck cancer patients, the circulation and implementation in the everyday routine of practicing dentists remain unknown. Purpose To analyze patterns of care for the prosthetic rehabilitation of head and neck cancer patients after radiotherapy in German speaking countries. Materials and methods An online survey consisting of 34 questions separated into three sections, (a) general inquiries, (b) treatment concepts, and (c) patient cases, was forwarded to university hospital departments for Prosthetic Dentistry and Oral and Maxillofacial Surgery, and members of different medical associations. Statistical differences between groups were analyzed using chi‐squared test (P < .05). Results From May to October 2019, 118 participants completed the survey. The majority practiced in university hospitals, had more than 5 years of work experience, and reported to be involved in <10 post radiation prosthetic rehabilitation cases per year. Rehabilitation protocols involving dental implants were implemented by oral/oral‐ and maxillofacial surgeons and prosthetic dentists, while general dentists favored implant‐free solutions. Xerostomia was recognized as a common problem for a successful prosthetic rehabilitation. The subsequent treatment choice with either fixed dental prostheses or removable dentures was divided among participants. Conclusions As treatment planning differed with regard to the participants' field of expertise and work environment, and most practitioners only handle a low number of cases, patients might benefit from centralization in larger institutes with a multidisciplinary structure. A high agreement between the practitioners' treatment concepts and the current state of research was observed. While the choice between a mucosa‐ or tooth‐supported, and an implant‐supported restoration depends on numerous individual factors, guidelines derived from longitudinal studies would enhance evidence‐based treatment in this field

    Search for stop and higgsino production using diphoton Higgs boson decays

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    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 (stop) 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 inverse femtobarns of proton-proton collision data at sqrt(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 stop mass below 360 to 410 GeV, depending on the higgsino mass

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV