76 research outputs found
Biomimetic coatings enhance tribocorrosion behavior and cell responses of commercially pure titanium surfaces
CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOBiofunctionalized surfaces for implants are currently receiving much attention in the health care sector. Our aims were ( 1) to create bioactive Ti-coatings doped with Ca, P, Si, and Ag produced by microarc oxidation ( MAO) to improve the surface properties of biomedical implants, ( 2) to investigate the TiO2 layer stability under wear and corrosion, and ( 3) to evaluate human mesenchymal stem cells ( hMSCs) responses cultured on the modified surfaces. Tribocorrosion and cell experiments were performed following the MAO treatment. Samples were divided as a function of different Ca/P concentrations and treatment duration. Higher Ca concentration produced larger porous and harder coatings compared to the untreated group ( p<0.001), due to the presence of rutile structure. Free potentials experiments showed lower drops ( 0.6 V) and higher coating lifetime during sliding for higher Ca concentration, whereas lower concentrations presented similar drops ( 0.8 V) compared to an untreated group wherein the drop occurred immediately after the sliding started. MAO-treated surfaces improved the matrix formation and osteogenic gene expression levels of hMSCs. Higher Ca/P ratios and the addition of Ag nanoparticles into the oxide layer presented better surface properties, tribocorrosive behavior, and cell responses. MAO is a promising technique to enhance the biological, chemical, and mechanical properties of dental implant surfaces. (C) 2016 American Vacuum Society.Biofunctionalized surfaces for implants are currently receiving much attention in the health care sector. Our aims were ( 1) to create bioactive Ti-coatings doped with Ca, P, Si, and Ag produced by microarc oxidation ( MAO) to improve the surface properties of biomedical implants, ( 2) to investigate the TiO2 layer stability under wear and corrosion, and ( 3) to evaluate human mesenchymal stem cells ( hMSCs) responses cultured on the modified surfaces. Tribocorrosion and cell experiments were performed following the MAO treatment. Samples were divided as a function of different Ca/P concentrations and treatment duration. Higher Ca concentration produced larger porous and harder coatings compared to the untreated group ( p<0.001), due to the presence of rutile structure. Free potentials experiments showed lower drops ( 0.6 V) and higher coating lifetime during sliding for higher Ca concentration, whereas lower concentrations presented similar drops ( 0.8 V) compared to an untreated group wherein the drop occurred immediately after the sliding started. MAO-treated surfaces improved the matrix formation and osteogenic gene expression levels of hMSCs. Higher Ca/P ratios and the addition of Ag nanoparticles into the oxide layer presented better surface properties, tribocorrosive behavior, and cell responses. MAO is a promising technique to enhance the biological, chemical, and mechanical properties of dental implant surfaces.113114CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO11838-13-22013/08451-1The authors would like to thank the University of Illinois at Chicago for providing the facilities to perform this study, Rush University Medical Center on behalf of R. Urban for the SEM facility, Denise Carleto Andia for providing the human bone marrow stromal cells for some cell experiments, Rafael Parra from Univ Estadual Paulista (Sorocaba, Brazil) for his contribution and support in the Plasma Technology Laboratory, the Coordination for the Improvement of Higher Level Personnel (CAPES) from Brazil for the doctoral fellowship of the first author (PDSE Proc. 11838-13-2), the State of Sao Paulo Research Foundation (FAPESP) for Grant No. 2013/08451-1, the National Science Foundation (NSF) for Grant No. 1067424, and finally financial support from NIH R03 AR064005
Measurement of neutron-proton capture in the SNO+ water phase
The SNO+ experiment collected data as a low-threshold water Cherenkov
detector from September 2017 to July 2019. Measurements of the 2.2-MeV
produced by neutron capture on hydrogen have been made using an Am-Be
calibration source, for which a large fraction of emitted neutrons are produced
simultaneously with a 4.4-MeV . Analysis of the delayed coincidence
between the 4.4-MeV and the 2.2-MeV capture revealed a
neutron detection efficiency that is centered around 50% and varies at the
level of 1% across the inner region of the detector, which to our knowledge is
the highest efficiency achieved among pure water Cherenkov detectors. In
addition, the neutron capture time constant was measured and converted to a
thermal neutron-proton capture cross section of mb
Measurement of the 8B solar neutrino flux in SNO+ with very low backgrounds
A measurement of the 8B solar neutrino flux has been made using a 69.2 kt-day dataset acquired with the SNO+ detector during its water commissioning phase. At energies above 6 MeV the dataset is an extremely pure sample of solar neutrino elastic scattering events, owing primarily to the detector’s deep location, allowing an accurate measurement with relatively little exposure. In that energy region the best fit background rate is 0.25+0.09−0.07 events/kt−day, significantly lower than the measured solar neutrino event rate in that energy range, which is 1.03+0.13−0.12 events/kt−day. Also using data below this threshold, down to 5 MeV, fits of the solar neutrino event direction yielded an observed flux of 2.53+0.31−0.28(stat)+0.13−0.10(syst)×106 cm−2 s−1, assuming no neutrino oscillations. This rate is consistent with matter enhanced neutrino oscillations and measurements from other experiments
Investigation of the splitting of quark and gluon jets
The splitting processes in identified quark and gluon jets are investigated using longitudinal and transverse observables. The jets are selected from symmetric three-jet events measured in Z decays with the Delphi detector in 1991-1994. Gluon jets are identified using heavy quark anti-tagging. Scaling violations in identified gluon jets are observed for the first time. The scale energy dependence of the gluon fragmentation function is found to be about two times larger than for the corresponding quark jets, consistent with the QCD expectation TeX . The primary splitting of gluons and quarks into subjets agrees with fragmentation models and, for specific regions of the jet resolution TeX , with NLLA calculations. The maximum of the ratio of the primary subjet splittings in quark and gluon jets is TeX . Due to non-perturbative effects, the data are below the expectation at small TeX . The transition from the perturbative to the non-perturbative domain appears at smaller TeX for quark jets than for gluon jets. Combined with the observed behaviour of the higher rank splittings, this explains the relatively small multiplicity ratio between gluon and quark jets
Improved search for invisible modes of nucleon decay in water with the SNO+ detector
This paper reports results from a search for single and multi-nucleon
disappearance from the O nucleus in water within the \snoplus{} detector
using all of the available data. These so-called "invisible" decays do not
directly deposit energy within the detector but are instead detected through
their subsequent nuclear de-excitation and gamma-ray emission. New limits are
given for the partial lifetimes:
years, years, years,
years, and years at 90\% Bayesian
credibility level (with a prior uniform in rate). All but the () results improve on existing limits by a factor of about 3.info:eu-repo/semantics/publishedVersio
Search for Neutral Heavy Leptons Produced in Z Decays
Weak isosinglet Neutral Heavy Leptons () have been searched for using data collected by the DELPHI detector corresponding to hadronic~Z decays at LEP1. Four separate searches have been performed, for short-lived production giving monojet or acollinear jet topologies, and for long-lived giving detectable secondary vertices or calorimeter clusters. No indication of the existence of these particles has been found, leading to an upper limit for the branching ratio Z of about at 95\% confidence level for masses between 3.5 and 50 GeV/. Outside this range the limit weakens rapidly with the mass. %Special emphasis has been given to the search for monojet--like topologies. One event %has passed the selection, in agreement with the expectation from the reaction: %. The results are also interpreted in terms of limits for the single production of excited neutrinos
Search for scalar fermions and long-lived scalar leptons at centre-of-mass energies of 130 GeV to 172 GeV
Data taken by DELPHI during the 1995 and 1996 LEP runs have been used to search for the supersymmetric partners of electron, muon and tau leptons and of top and bottom quarks. The observations are in agreement with standard model predictions. Limits are set on sfermion masses. Searches for long lived scalar leptons from low scale supersymmetry breaking models exclude stau masses below 55~GeV/c at the 95\% confidence level, irrespective of the gravitino mass
Measurements of the leptonic branching fractions of the
Data collected with the DELPHI detector from 1993 to 1995 combined with previous DELPHI results for data from 1991 and 1992 yield the branching fractions B({\tau \rightarrow \mbox{\rm e} \nu \bar{\nu}}) = (17.877 \pm 0.109_{stat} \pm 0.110_{sys} )\% and
Measurement of the Quark and Gluon Fragmentation Functions in Hadronic Decays
The fragmentation functions and multiplicities in and light quark events are compared. The measured transverse and longitudinal components of the fragmentation function allow the gluon fragmentation function to be evaluated
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