Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 180
Filtrar
1.
Phys Rev Lett ; 118(15): 151801, 2017 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-28452532

RESUMO

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135 µ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66 µ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

3.
Phys Rev Lett ; 117(19): 192501, 2016 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-27858422

RESUMO

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

4.
Phys Rev Lett ; 116(18): 181801, 2016 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-27203315

RESUMO

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{µ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{µ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{µ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained µ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3} eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3} eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{µ} disappearance parameters measured by T2K.

5.
Eur J Vasc Endovasc Surg ; 51(3): 327-34, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26602322

RESUMO

OBJECTIVES: Stroke, myocardial infarction (MI), and death are complications of carotid artery stenting (CAS). The effect of baseline patient demographic factors, processes of care, and technical factors during CAS on the risk of stroke, MI, or death within 30 days of CAS in the International Carotid Stenting Study (ICSS) were investigated. METHODS: In ICSS, suitable patients with recently symptomatic carotid stenosis > 50% were randomly allocated to CAS or endarterectomy. Factors influencing the risk of stroke, MI, or death within 30 days of CAS were examined in a regression model for the 828 patients randomized to CAS in whom the procedure was initiated. RESULTS: Of the patients, 7.4% suffered stroke, MI, or death within 30 days of CAS. Independent predictors of risk were age (risk ratio [RR] 1.17 per 5 years of age, 95% CI 1.01-1.37), a right-sided procedure (RR 0.54, 95% CI 0.32-0.91), aspirin and clopidogrel in combination prior to CAS (compared with any other antiplatelet regimen, RR 0.59, 95% CI 0.36-0.98), smoking status, and the severity of index event. In patients in whom a stent was deployed, use of an open-cell stent conferred higher risk than use of a closed-cell stent (RR 1.92, 95% CI 1.11-3.33). Cerebral protection device (CPD) use did not modify the risk. CONCLUSIONS: Selection of patients for CAS should take into account symptoms, age, and side of the procedure. The results favour the use of closed-cell stents. CPDs in ICSS did not protect against stroke.


Assuntos
Artéria Carótida Primitiva/cirurgia , Estenose das Carótidas/cirurgia , Procedimentos Endovasculares/efeitos adversos , Infarto do Miocárdio/etiologia , Complicações Pós-Operatórias , Stents , Acidente Vascular Cerebral/etiologia , Endarterectomia das Carótidas/efeitos adversos , Europa (Continente)/epidemiologia , Humanos , Infarto do Miocárdio/mortalidade , Medição de Risco , Fatores de Risco , Acidente Vascular Cerebral/mortalidade , Taxa de Sobrevida/tendências , Fatores de Tempo , Resultado do Tratamento
7.
BMC Neurosci ; 16: 51, 2015 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-26260473

RESUMO

BACKGROUND: Recent evidence identifies the hippocampus, a brain structure commonly associated with learning and memory, as key to the regulation of food intake and the development and consequences of obesity. Intake of a high fat diet (HFD) results in altered consumptive behavior, hippocampal damage, and cognitive deficits. While many studies report the effects of HFD after chronic consumption and in the instance of obesity, few examine the events that occur following acute HFD consumption. In this study, male rats were fed either a control diet (10% fat by kcal) or HFD (45% fat by kcal) for 72 h. At the end of the 72-h period, serum and tissues were collected and weighed. Brains were rapidly frozen or formalin-fixed in preparation for qRT-PCR or immunohistochemistry, respectively. RESULTS: Acute intake of HFD resulted in higher serum levels of leptin and cholesterol, with no significant changes in final body weight or adipose tissue mass. In the dorsal hippocampus, transcription of the neuroprotective peptide galanin was significantly upregulated along with a trend for an increase in brain-derived neurotrophic factor and histone deacetylase 2 in the rats fed HFD. In the ventral hippocampus, there was a significant increase in histone deacetylase 4 and a decrease in galanin receptor 1 in this group. Results from immunohistochemistry validate strong presence of the galanin peptide in the CA1/CA2 region of the dorsal hippocampus. CONCLUSIONS: These results provide evidence for a distinct response in specific functional regions of the hippocampus following acute HFD intake.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Galanina/metabolismo , Hipocampo/metabolismo , Tecido Adiposo/patologia , Tecido Adiposo/fisiologia , Animais , Peso Corporal/fisiologia , Colesterol/sangue , Ingestão de Alimentos/fisiologia , Ensaio de Imunoadsorção Enzimática , Expressão Gênica , Imuno-Histoquímica , Leptina/sangue , Masculino , Tamanho do Órgão , Ratos Long-Evans , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Tempo
8.
Int J Sport Nutr Exerc Metab ; 25(2): 136-44, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25029040

RESUMO

Assessment of physical activity in clinical bone studies is essential. Two bone-specific physical activity scoring methods, the Bone Loading History Questionnaire (BLHQ) and Bone-Specific Physical Activity Questionnaire (BPAQ), have shown correlations with bone density and geometry, but not architecture. The purpose of this study was to determine relationships between physical activity scoring methods and bone architecture in non-Hispanic white adolescent females (N = 24; 18-19 years of age). Bone loading scores (BLHQ [hip and spine] and past BPAQ) and energy expenditure (7-day physical activity recall) were determined from respective questionnaires. Estimates of trabecular and cortical bone architecture at the nondominant radius and tibia were assessed via magnetic resonance imaging. Total body and regional areal bone mineral density (aBMD), as well as total body fat mass and fat-free soft tissue (FFST) mass were assessed via dual energy X-ray absorptiometry. Pearson's correlations and partial correlations adjusting for height, total body fat mass, and FFST were performed. Hip BLHQ scores were correlated with midtibia cortical volume (r = .43; p = .03). Adjusted hip and spine BLHQ scores were correlated with all midtibia cortical measures (r = .50-0.58; p < .05) and distal radius apparent trabecular number (r = .46-0.53; p < .05). BPAQ scores were correlated with all midtibia cortical (r = .41-0.51; p < .05) and most aBMD (r = .47-0.53; p < .05) measures. Energy expenditure was inversely associated with femoral neck aBMD only after statistical adjustment (r = .49, p < .05). These data show that greater load-specific physical activity scores, but not energy expenditure, are indicative of greater midtibia cortical bone quality, thus supporting the utility of these instruments in musculoskeletal research.


Assuntos
Metabolismo Energético , Exercício Físico , Tíbia , Suporte de Carga , Absorciometria de Fóton , Adolescente , Adulto , Densidade Óssea , Feminino , Fêmur , Quadril , Humanos , Perna (Membro) , Imageamento por Ressonância Magnética/métodos , Esforço Físico , Coluna Vertebral , Esportes , Tíbia/anatomia & histologia , Tíbia/crescimento & desenvolvimento , População Branca , Adulto Jovem
9.
Phys Rev Lett ; 112(6): 061802, 2014 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-24580687

RESUMO

The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3) eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L.

10.
Phys Rev Lett ; 112(18): 181801, 2014 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-24856687

RESUMO

New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νµ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3) eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3) eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.

11.
Phys Rev Lett ; 113(24): 241803, 2014 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-25541766

RESUMO

The T2K off-axis near detector ND280 is used to make the first differential cross-section measurements of electron neutrino charged current interactions at energies ∼1 GeV as a function of electron momentum, electron scattering angle, and four-momentum transfer of the interaction. The total flux-averaged ν(e) charged current cross section on carbon is measured to be ⟨σ⟩(ϕ)=1.11±0.10(stat)±0.18(syst)×10⁻³8 cm²/nucleon. The differential and total cross-section measurements agree with the predictions of two leading neutrino interaction generators, NEUT and GENIE. The NEUT prediction is 1.23×10⁻³8 cm²/nucleon and the GENIE prediction is 1.08×10⁻³8 cm²/nucleon. The total ν(e) charged current cross-section result is also in agreement with data from the Gargamelle experiment.

12.
Cell Tissue Res ; 354(3): 743-50, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24026435

RESUMO

The bioactive flavonoid p-hydroxycinnamic acid (HCA), which is an intermediate-metabolic substance in plants and fruits, is synthesized from tyrosine. The biological effect of HCA is poorly understood. Among cinnamic acid and its related compounds, HCA has a specific-anabolic effect on bone, being found to stimulate osteoblastogenesis and to inhibit osteoclastogenesis through the suppression of NF-κB signaling, thereby preventing bone loss. Bone marrow mesenchymal stem cells give rise to ostoblasts and adipocytes. HCA might therefore have effects on osteoblastogenesis and adipogenesis in bone marrow culture. This study demonstrates (1) that HCA has stimulatory effects on osteoblastogenesis and mineralization and suppressive effects on adipogenesis in mouse bone marrow culture and (2) that HCA depresses adipogenesis in mouse 3T3-L1 preadipocytes in vitro. Such effects of HCA might be involved in the differentiation of mesenchymal stem cells.


Assuntos
Adipogenia/efeitos dos fármacos , Células da Medula Óssea/efeitos dos fármacos , Ácidos Cumáricos/farmacologia , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Células 3T3-L1 , Adipócitos/citologia , Adipócitos/efeitos dos fármacos , Animais , Células da Medula Óssea/citologia , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Osteoblastos/citologia , Propionatos , Estimulação Química
13.
Phys Rev Lett ; 111(21): 211803, 2013 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-24313479

RESUMO

The T2K Collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×10(20) protons on target. In the absence of neutrino oscillations, 205±17 (syst) events are expected to be detected while only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum, assuming three neutrino flavors and normal mass hierarchy yields a best-fit mixing angle sin2(θ23)=0.514±0.082 and mass splitting |Δm(32)(2)|=2.44(-0.15)(+0.17)×10(-3) eV2/c4. Our result corresponds to the maximal oscillation disappearance probability.

14.
Clin Radiol ; 68(3): 232-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23102717

RESUMO

AIM: To determine the negative predictive value of 16 channel multisection computed tomography angiography (CTA) for detecting aneurysms in spontaneous subarachnoid haemorrhage (SAH), using digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: The prospectively collected cerebral angiogram database of Department of Neuroradiology, Atkinson Morley Regional Neuroscience Centre was used to identify 200 consecutive patients who had undergone DSA for SAH. Of these, 176 had undergone CTA prior to DSA. Clinical details and radiology reports were correlated and images of positive investigations reviewed. RESULTS: DSA showed one or more cerebral aneurysms in 105 (60%) patients. These were correctly reported on CTA in 100. CTA was reported negative for aneurysms in 74 patients. Of these five were false negative and had aneurysms detected on DSA. In the CTA/DSA negative group, 11 (16%) patients had classical perimesencephalic clinical syndrome and blood distribution. There were two false positives at CTA. For ruptured cerebral aneurysms, CTA had 95.2% sensitivity, 97.2% specificity, 98.1% positive predictive value, and 93.2% negative predictive value. CONCLUSION: The sensitivity and negative predictive value of CTA for ruptured aneurysms remains imperfect. Continued use of DSA is recommended in most patients with a negative CTA after acute SAH. Confirmation of a negative CTA result with DSA may not be routinely required in patients with perimesencephalic syndrome.


Assuntos
Aneurisma Roto/diagnóstico por imagem , Angiografia Cerebral/métodos , Aneurisma Intracraniano/diagnóstico por imagem , Hemorragia Subaracnóidea/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiografia Digital , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Sensibilidade e Especificidade
17.
J Bone Miner Metab ; 29(1): 44-53, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20458605

RESUMO

Few childhood studies have investigated racial differences in volumetric bone mineral density (vBMD), bone geometry, and bone strength indices measured by three-dimensional bone imaging. The purpose of this study was to compare trabecular and cortical bone parameters at the radius and tibia between late adolescent white and black females using peripheral quantitative computed tomography (QCT). White (n = 25) and black females (n = 25), 18-19 years of age, were pair-matched for age, height, and fat-free soft tissue mass. Peripheral QCT scans were obtained at the 4% (trabecular bone), 20% (cortical bone), and 66% [muscle cross-sectional area (CSA)] sites from the distal metaphyses. Bone strength was determined from vBMD and bone geometry to calculate bone strength index (BSI; trabecular site) and polar strength-strain index (SSI; cortical site). Radial SSI was not different between groups; however, blacks had greater radial BSI (P = 0.02) than whites. After adjustment for the longer forearm in blacks, the greater radial BSI in blacks no longer remained. At the tibia, blacks versus whites had greater bone strength at the trabecular and cortical bone sites (BSI, P = 0.03; SSI, P = 0.04, respectively). When controlling for differences in tibial length and muscle CSA, the higher estimates of bone strength persisted in blacks versus whites (BSI, P = 0.01; SSI, P = 0.02). Our data suggest that when differences in body size are considered, late adolescent black versus white females have a stronger bone profile, due to greater bone geometry and vBMD, at the trabecular and cortical regions of the tibia but not at the radius.


Assuntos
Osso e Ossos/fisiologia , Adolescente , Adulto , Antropometria , População Negra , Densidade Óssea/fisiologia , Osso e Ossos/diagnóstico por imagem , Feminino , Humanos , Atividade Motora/fisiologia , Tomografia Computadorizada por Raios X , População Branca , Adulto Jovem
18.
J Physiol Biochem ; 66(3): 197-203, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20535649

RESUMO

Clenbuterol, a beta(2)-adrenergic receptor (beta(2)-AR) selective agonist, has been shown to decrease body fat in animals and can induce apoptosis in adipose tissue in mice. We hypothesized that direct actions of a beta-adrenergic receptor agonist on adipocytes could trigger the observed apoptotic effect. The hypothesis was inspected by investigating the direct effect of clenbuterol on apoptosis, adipogenesis, and lipolysis in vitro using the 3T3-L1 cell line and rat primary adipocytes. Cells were treated with 10(-9) to 10(-5) M clenbuterol depending on the experiments. There was no apoptotic effect of clenbuterol both in 3T3-L1 cells and rat primary adipocytes. Adipogenesis monitored by Oil Red O staining and AdipoRed assay was modestly decreased by clenbuterol treatment (p < 0.05). In fully differentiated primary adipocytes, clenbuterol increased basal lipolysis compared with the control (p < 0.01). In summary, direct stimulation of beta(2)-AR by clenbuterol does not cause apoptosis in adipocytes, despite a direct lipolytic stimulation and attenuation of adipogenesis.


Assuntos
Adipócitos/efeitos dos fármacos , Adipogenia/efeitos dos fármacos , Agonistas Adrenérgicos beta/farmacologia , Apoptose/efeitos dos fármacos , Clembuterol/farmacologia , Lipólise/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Camundongos , Ratos
19.
J Comp Pathol ; 175: 5-12, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32138843

RESUMO

Four different models of infection of chickens with Mycoplasma gallisepticum (MG) were evaluated. Normal or immunosuppressed chicks (10 days old) were infected with the MG Rlow strain via eye and nasal drops or by direct air sac injection. Bacterial load in the lungs was quantified and air sac and tracheal lesion scores, tracheal mucosal thickness and humoral immune responses were assessed. Serum antibody responses were assessed by use of a serum plate agglutination test. Three days post infection (dpi), all immunosuppressed chicks had developed significant respiratory signs. Chicks infected via air sac injection had significant differences in serum antibody and gross lesion scores at 5 dpi. All chicks had developed pathological changes by 7 dpi. Air sac inoculation of immunosuppressed chicks produced more significant (P ≤0.05) lesions, and these birds had the highest bacterial load in the lungs compared with other groups.


Assuntos
Modelos Animais de Doenças , Hospedeiro Imunocomprometido , Infecções por Mycoplasma , Doenças das Aves Domésticas , Animais , Galinhas , Infecções por Mycoplasma/imunologia , Mycoplasma gallisepticum , Doenças das Aves Domésticas/imunologia
20.
J Nutr Biochem ; 20(2): 140-8, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18547799

RESUMO

Genistein, a major soy isoflavone, has been reported to exhibit antiadipogenic and proapoptotic potential in vivo and in vitro. It is also a phytoestrogen which has high affinity to estrogen receptor beta. In this study, we determined the effect of genistein on adipogenesis and estrogen receptor (ER) alpha and beta expression during differentiation in primary human preadipocytes. Genistein inhibited lipid accumulation in a dose-dependent manner at concentrations of 6.25 microM and higher, with 50 microM genistein inhibiting lipid accumulation almost completely. Low concentrations of genistein (3.25 microM) increased cell viability and higher concentrations (25 and 50 microM) decreased it by 16.48+/-1.35% (P<.0001) and 50.68+/-1.34% (P<.0001). Oil Red O staining was used to confirm the effects on lipid accumulation. The inhibition of lipid accumulation was associated with inhibition of glycerol-3-phosphate dehydrogenase activity and down-regulation of expression of adipocyte-specific genes, including peroxisome proliferator-activated receptor gamma, CCAAT/enhancer binding protein alpha, glycerol-3-phosphate dehydrogenase, adipocyte fatty acid binding protein, fatty acid synthase, sterol regulatory element-binding protein 1, perilipin, leptin, lipoprotein lipase and hormone-sensitive lipase. These effects of genistein during the differentiation period were associated with down-regulation of ERalpha and ERbeta expression. This study adds to the elucidation of the molecular pathways involved in the inhibition of adipogenesis by phytoestrogens.


Assuntos
Adipócitos/citologia , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Genisteína/farmacologia , Adipócitos/efeitos dos fármacos , Adipócitos/enzimologia , Criopreservação , Sondas de DNA , Glicerolfosfato Desidrogenase/metabolismo , Humanos , Cinética , PPAR gama/genética , RNA/efeitos dos fármacos , RNA/genética , RNA Ribossômico 18S/efeitos dos fármacos , RNA Ribossômico 18S/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA