641 research outputs found

    Current concepts: tissue engineering and regenerative medicine applications in the ankle joint

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    Tissue engineering and regenerative medicine (TERM) has caused a revolution in present and future trends of medicine and surgery. In different tissues, advanced TERM approaches bring new therapeutic possibilities in either general population as in young patients and high-level athletes, improving restoration of biological functions and rehabilitation. The mainstream components required to obtain a functional regeneration of tissues may include biodegradable scaffolds, drugs or growth factors and different cell types (either autologous or heterologous) that can be cultured in bioreactor systems (in vitro) prior implantation into the patient. Particularly in the ankle, that is subject of many different injuries (e.g. acute, chronic, traumatic, degenerative), there is still no definitive and feasible answer to “conventional” methods. This review aims to provide current concepts of TERM applications to ankle injuries under pre-clinical and/or clinical research applied to skin, tendon, bone and cartilage problems. A particular attention has been given to biomaterials design and scaffolds processing with potential use in osteochondral ankle lesions.The authors acknowledge the Portuguese Foundation for Science and Technology (FCT) through the POCTI and FEDER programmes, including Project OsteoCart (grant no. PTDC/CTM-BPC/115977/2009) for providing funds

    Engineering egress data considering pedestrians with reduced mobility

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    To quantify the evacuation process, evacuation practitioners use engineering egressdata describing the occupant movement characteristics. These data are typicallybased to young and fit populations. However, the movement abilities of occupantswho might be involved in evacuations are becoming more variable—with the buildingpopulations of today typically including increasing numbers of individuals: withimpairments or who are otherwise elderly or generally less mobile. Thus, there willbe an increasing proportion of building occupants with reduced ability to egress. Forsafe evacuation, there is therefore a need to provide valid engineering egress dataconsidering pedestrians with disabilities. Gwynne and Boyce recently compiled aseries of data sets related to the evacuation process to support practitioner activitiesin the chapter Engineering Data in the SFPE Handbook of Fire Protection Engineering.This paper supplements these data sets by providing information on and presentingdata obtained from additional research related to the premovement and horizontalmovement of participants with physical-, cognitive-, or age-related disabilities. Theaim is to provide an overview of currently available data sets related to, and keyfactors affecting the egress performance of, mixed ability populations which could beused to guide fire safety engineering decisions in the context of building design

    A search for charged massive long-lived particles

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    We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb1^{-1} of integrated luminosity collected with the D0 detector at the Fermilab Tevatron ppˉp\bar{p} collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss (dE/dx)(dE/dx) inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.Comment: submitted to Phys. Rev. Letter

    Measurements of single top quark production cross sections and |Vtb| in ppbar collisions at sqrt{s}=1.96 TeV

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    We present measurements of production cross sections of single top quarks in \ppbar collisions at s=1.96  TeV\sqrt{s}=1.96\;\rm TeV in a data sample corresponding to an integrated luminosity of 5.4  fb15.4\;\rm fb^{-1} collected by the D0 detector at the Fermilab Tevatron Collider. We select events with an isolated electron or muon, an imbalance in transverse energy, and two, three, or four jets, with one or two of them containing a bottom hadron. We obtain an inclusive cross section of \sigma({\ppbar}{\rargap}tb+X, tqb+X) = 3.43\pm^{0.73}_{0.74}\;\rm pb and use it to extract the CKM matrix element 0.79<Vtb10.79 < |V_{tb}| \leq 1 at the 95% C.L. We also measure \sigma({\ppbar}{\rargap}tb+X) = 0.68\pm^{0.38}_{0.35}\;\rm pb and \sigma({\ppbar}{\rargap}tqb+X) = 2.86\pm^{0.69}_{0.63}\;\rm pb when assuming, respectively, tqbtqb and tbtb production rates as predicted by the standard model.Comment: 11 pages, 8 figures, submitted to Phys. Rev.

    Zgamma production and limits on anomalous ZZgamma and Zgammagamma couplings in ppbar collisions at sqrt(s)=1.96 TeV

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    We present a measurement of ppbar->Zgamma->ll+gamma (l = e, mu) production with a data sample corresponding to an integrated luminosity of 6.2 fb^{-1} collected by the D0 detector at the Fermilab Tevatron ppbar Collider. The results of the electron and muon channels are combined, and we measure the total production cross section and the differential cross section dsigma/dp_T^gamma, where p_T^gamma is the momentum of the photon in the plane transverse to the beamline. The results obtained are consistent with the standard model predictions from next-to-leading order calculations. We use the transverse momentum spectrum of the photon to place limits on anomalous ZZgamma and Zgammagamma couplings

    Search for a Narrow ttbar Resonance in ppbar Collisions at sqrt{s}=1.96 TeV

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    We report a search for a narrow ttbar resonance that decays into a lepton+jets final state based on an integrated luminosity of 5.3/fb of proton-antiproton collisions at sqrt{s}=1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the production cross section of such a resonance multiplied by its branching fraction to ttbar which we compare to predictions for a leptophobic topcolor Z' boson. We exclude such a resonance at the 95% confidence level for masses below 835 GeV.Comment: 7 pages, 3 figures, submitted to Physical Review Letter

    Precise measurement of the top quark mass in the dilepton channel at D0

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    We measure the top quark mass (mt) in ppbar collisions at a center of mass energy of 1.96 TeV using dilepton ttbar->W+bW-bbar->l+nubl-nubarbbar events, where l denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider. We obtain mt = 174.0 +- 1.8(stat) +- 2.4(syst) GeV, which is in agreement with the current world average mt = 173.3 +- 1.1 GeV. This is currently the most precise measurement of mt in the dilepton channel.Comment: 7 pages, 4 figure

    Direct measurement of the mass difference between top and antitop quarks

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    We present a direct measurement of the mass difference between top and antitop quarks (dm) in lepton+jets top-antitop final states using the "matrix element" method. The purity of the lepton+jets sample is enhanced for top-antitop events by identifying at least one of the jet as originating from a b quark. The analyzed data correspond to 3.6 fb-1 of proton-antiproton collisions at 1.96 TeV acquired by D0 in Run II of the Fermilab Tevatron Collider. The combination of the e+jets and mu+jets channels yields dm = 0.8 +/- 1.8 (stat) +/- 0.5 (syst) GeV, which is in agreement with the standard model expectation of no mass difference.Comment: submitted to Phys. Rev.
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