527 research outputs found
Caracterização físico-química de seis hidroxiapatitas comerciais para aplicações médico-odontológicas como material de enxerto
O objetivo desse trabalho foi caracterizar seis hidroxiapatitas granulares para aplicação em área médico-odontológica como material de enxerto. Estes materiais foram produzidos por quatro diferentes fabricantes e são todos facilmente disponíveis no mercado brasileiro. A caracterização físico-química foi realizada por meio de microscopia eletrônica de varredura, difração de raios-X, espectroscopia de infravermelho e área superficial específica (BET). Os resultados mostraram que apenas um dos produtos teve a caracterização perfeitamente de acordo com a especificação do fabricante. Os parâmetros de cristalinidade, área superficial e composição podem ser usados para estimar a biodegradabilidade da hidroxiapatita e como critério de controle de qualidade desses materiais.The aim of this work was to characterize six hydroxyapatites in granular form for applications in medicine and dentistry as bone graft and to compare with manufacturers' specification. These samples were produced by four different manufacturers, and all of them are easily available in the Brazilian market. Physicochemical characterization was carried out by using electron microscopy (SEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR) and surface area (BET) measurements. The results show that just one hydroxyapatite sample exhibited characterisitics in perfect agreement with the manufacturers' specifications. The studied parameters, namely crystallinity, surface area and composition may be used to estimate hydroxyapatite's biodegradability and as a criterion for quality control
Hydroxyapatite crystallinity does not affect the repair of critical size bone defects
OBJECTIVE: The physicochemical properties of hydroxyapatite (HA) granules were observed to affect the biological behavior of graft materials. The aim of this work was to analyze the tissue response of two HA granules with different crystallinity and Ca/P ratio in vivo. MATERIAL AND METHODS: The HA granules were produced in the Biomaterials Laboratory (COPPE/UFRJ). The testing materials were HA granules presenting a Ca/P molar ratio of 1.60 and 28% crystallinity (HA-1), and a Ca/P molar ratio of 1.67 and 70% crystallinity (HA-2). Both HAs were implanted into a critical-size calvaria rat defects. RESULTS: To note, in the control group, the bone defects were filled with blood clot only. Descriptive and histomorphometric analyses after 1, 3, and 6 months postoperatively showed mild inflammatory infiltrate, mainly comprising macrophage-like and multinucleated giant cells, and an increase in the volume density of the fibrous tissues (
Comparative study of hydroxyapatite coatings obtained by Sol-Gel and electrophoresis on titanium sheets
A comparative study of two coating methods on titanium (Ti) substrates, sol-gel and electrophoresis processes, was performed. Before coating, two different surface treatments were employed. The hydroxyapatite (HA) powder were characterized by infrared spectroscopy (FTIR) and X-ray diffraction (XRD) while coated samples were examined by using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). Both techniques seem to be suitable to coat Ti. A previous surface treatment on metallic titanium seems to be fundamental to enhance coat uniformity and adhesion that was estimated by the adhesive tape test. The decrease in calcination temperature did not affect the coating adhesion.The authors thank the financial support of CAPES, CNPq, FAPERJ, and the cooperative project between CNPq/Brasil and MES/Cuba.Peer reviewe
Carbamazepine inhibits angiotensin I-converting enzyme, linking it to the pathogenesis of temporal lobe epilepsy
We find that a common mutation that increases angiotensin I-converting enzyme activity occurs with higher frequency in male patients suffering from refractory temporal lobe epilepsy. However, in their brains, the activity of the enzyme is downregulated. As an explanation, we surprisingly find that carbamazepine, commonly used to treat epilepsy, is an inhibitor of the enzyme, thus providing a direct link between epilepsy and the renin-angiotensin and kallikrein-kinin systems. Translational Psychiatry (2012) 2, e93; doi:10.1038/tp.2012.21; published online 13 March 2012INNTConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Dept Biophys, BR-04023032 São Paulo, BrazilUniversidade Federal de São Paulo, BR-04023032 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pathol, BR-04023032 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Neurol & Neurosurg, BR-04023032 São Paulo, BrazilUniv São Paulo, Sch Arts Sci & Humanities, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Sci & Technol, BR-04023032 São Paulo, BrazilNove de Julho Univ UNINOVE, Dept Rehabil Sci, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04023032 São Paulo, BrazilUniversidade Federal de São Paulo, BR-04023032 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pathol, BR-04023032 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Neurol & Neurosurg, BR-04023032 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Sci & Technol, BR-04023032 São Paulo, BrazilWeb of Scienc
Physicochemical characterization of six commercial hydroxyapatites for medical-dental applicatons as bone graft
Patologias atuais: a compulsão e a sociedade dos excessos: Current pathologies: compulsion and the society of excesses
O artigo em tela tem por objetivo analisar os aspectos biopsicossociais da conduta compulsiva de consumo. Propõe-se a apresentar os elementos psicológicos contidos nesse comportamento, além de verificar quais são os resultados decorrentes dessa compulsão. O consumo compulsivo, também chamado de oniomania, é um transtorno causado pela ansiedade despertada pela necessidade de comprar e saciada, somente, quando é materializada a aquisição daquilo que se deseja comprar. O estudo em questão pode ser classificado como sendo de cunho bibliográfico, a partir da análise de documentos publicados em forma de artigos científicos e livros em formato digital
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
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