Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 585 )

2018 ( 817 )

2017 ( 753 )

2016 ( 1105 )

Custom range...

Search Results: 1 - 10 of 461790 matches for " A. Biselli "
All listed articles are free for downloading (OA Articles)
Page 1 /461790
Display every page Item
Study of polarized-e polarized-p --> e-prime p pi0 in the Delta(1232) mass region using polarization asymmetries
A. Biselli
Physics , 2003, DOI: 10.1103/PhysRevC.68.035202
Abstract: Measurements of the angular distributions of target and double spin asymmetries for the Delta(1232) in the exclusive channel (polarized-p polarized-e,e-prime p)pi0 obtained at Jefferson Lab in the Q2 range from 0.5 to 1.5 gev2 are presented. Results of the asymmetries are compared with the unitary isobar model, dynamical models, and the effective Lagrangian theory. Sensitivity to the different models was observed, particularly in relation to the description of background terms on which the target asymmetry depends significantly.
First measurement of target and double spin asymmetries for polarized e- polarized p --> e p pi0 in the nucleon resonance region above the Delta(1232)
CLAS Collaboration,A. S. Biselli
Physics , 2008, DOI: 10.1103/PhysRevC.78.045204
Abstract: The exclusive channel polarized proton(polarized e,e prime p)pi0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770 GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the pi0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A_{1/2} and S_{1/2} for the Roper resonance N(1400)P11, and the N(1535)S11 and N(1520)D13 states.
Longitudinal target-spin asymmetries for deeply virtual Compton scattering
E. Seder,A. Biselli,S. Pisano,S. Niccolai,the CLAS Collaboration
Physics , 2014, DOI: 10.1103/PhysRevLett.114.032001
Abstract: A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6-GeV electron beam, a longitudinally polarized proton target and the CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for $ep\to e'p'\gamma$ events, which arise from the interference of the deeply virtual Compton scattering and the Bethe-Heitler processes, were extracted over the widest kinematics in $Q^2$, $x_B$, $t$ and $\phi$, for 166 four-dimensional bins. In the framework of Generalized Parton Distributions (GPDs), at leading twist the $t$ dependence of these asymmetries provides insight on the spatial distribution of the axial charge of the proton, which appears to be concentrated in its center. These results also bring important and necessary constraints for the existing parametrizations of chiral-even GPDs.
Deeply virtual Compton scattering at Jefferson Laboratory
Angela Biselli
Physics , 2015,
Abstract: The generalized parton distributions (GPDs) have emerged as a universal tool to describe hadrons in terms of their elementary constituents, the quarks and the gluons. Deeply virtual Compton scattering (DVCS) on a proton or neutron ($N$), $e N \rightarrow e' N' \gamma$, is the process more directly interpretable in terms of GPDs. The amplitudes of DVCS and Bethe-Heitler, the process where a photon is emitted by either the incident or scattered electron, can be accessed via cross-section measurements or exploiting their interference which gives rise to spin asymmetries. Spin asymmetries, cross sections and cross-section differences can be connected to different combinations of the four leading-twist GPDs (${H}$, ${E}$, ${\tilde{H}}$, ${\tilde{E}}$) for each quark flavors, depending on the observable and on the type of target. This paper gives an overview of recent experimental results obtained for DVCS at Jefferson Laboratory in the halls A and B. Several experiments have been done extracting DVCS observables over large kinematics regions. Multiple measurements with overlapping kinematic regions allow to perform a quasi-model independent extraction of the Compton form factors, which are GPDs integrals, revealing a 3D image of the nucleon.
Single and double spin asymmetries for deeply virtual Compton scattering measured with CLAS and a longitudinally polarized proton target
S. Pisano,A. Biselli,S. Niccolai,E. Seder,M. Guidal,M. Mirazita,the CLAS Collaboration
Physics , 2015, DOI: 10.1103/PhysRevD.91.052014
Abstract: Single-beam, single-target, and double-spin asymmetries for hard exclusive photon production on the proton $\vec{e}\vec{p} \to e' p'\gamma$ are presented. The data were taken at Jefferson Lab using the CLAS detector and a longitudinally polarized ${}^{14}$NH$_3$ target. The three asymmetries were measured in 165 4-dimensional kinematic bins, covering the widest kinematic range ever explored simultaneously for beam and target-polarization observables in the valence quark region. The kinematic dependences of the obtained asymmetries are discussed and compared to the predictions of models of Generalized Parton Distributions. The measurement of three DVCS spin observables at the same kinematic points allows a quasi-model-independent extraction of the imaginary parts of the $H$ and $\tilde{H}$ Compton Form Factors, which give insight into the electric and axial charge distributions of valence quarks in the proton.
Utilidade clínica da angiografia coronariana em pacientes com disfun??o ventricular esquerda
Melo, Rodrigo Morel Vieira de;Melo, Eduardo Fran?a Pessoa de;Biselli, Bruno;Souza, Germano Emilio Concei??o;Bocchi, Edimar Alcides;
Arquivos Brasileiros de Cardiologia , 2012, DOI: 10.1590/S0066-782X2012005000035
Abstract: background: performing a coronary angiography in patients with heart failure of unknown etiology is often justified by the diagnostic assessment of ischemic heart disease. however, the clinical benefit of this strategy is not known. objective: to evaluate the prevalence of ischemic heart disease by angiographic criteria in patients with heart failure and reduced ejection fraction of unknown etiology, as well as its impact on therapy decisions. methods: consecutive outpatients with heart failure and systolic dysfunction, who had an indication for coronary angiography to clarify the etiology of heart disease were assessed from 1 january 2009 to december 31, 2010. patients diagnosed with coronary artery disease, positive serology for chagas disease, congenital heart disease, valve disease or patients undergoing cardiac transplantation were excluded from the analysis. the sample was divided into two groups according to the indication for catheterization. group-1: symptomatic due to angina or heart failure. group-2: presence of > 2 risk factors for coronary artery disease results: one hundred and seven patients were included in the analysis, with 51 (47.7%) patients in group 1 and 56 (52.3%) in group 2. the prevalence of ischemic heart disease was 9.3% (10 patients), and all belonged to group 1 (p = 0.0001). during follow-up, only 4 (3.7%) were referred for cabg; 3 (2.8%) patients had procedure-related complications. conclusion: in our study, coronary angiography in patients with heart failure and systolic dysfunction of unknown etiology, although supported by current guidelines, did not show benefits when performed only due to the presence of risk factors for coronary artery disease.
Avalia??o da influência da nulidade dos genótipos GSTT1 e GSTM1 na carcinogênese em cabe?a e pesco?o
Goloni-Bertollo, Eny Maria;Biselli, Joice Matos;Corrêa,a Carolina deLima;Maníglia, José Victor;Rossit, Andréa Regina Baptista;Ruiz, Mariangela Torreglosa;Pavarino-Bertelli, érika Cristina;
Revista da Associa??o Médica Brasileira , 2006, DOI: 10.1590/S0104-42302006000500028
Abstract: background: to evaluate the influence of gstm1 and gstt1 null genotypes in head and neck carcinogenesis. methods: the frequencies of gstm1 and gstt1 null genotypes were evaluated by multiplex polymerase chain reaction (pcr) in 45 patients with head and neck squamous cell carcinoma and in 45 control group individuals. both groups were composed of smokers paired by gender, age and race. results: the gstt1 null genotype was found in 24.4% of the patients and 17.7% of the control group (p= 0.606), while 44.4% of the patients and 48.8% of the control group were bearers of the gstm1 null genotype (p=0.832). no associations between gstt1 and gstmi null genotypes and primary tumor sites were found. conclusion: in our study, it was impossible to establish the influence of the gstt1 and gstm1 null genotypes in head and neck carcinogenesis.
5-Methyltetrahydrofolate-homocysteine methyltransferase gene polymorphism (MTR) and risk of head and neck cancer
Galbiatti, A.L.S.;Ruiz, M.T.;Biselli-Chicote, P.M.;Raposo, L.S.;Maniglia, J.V.;Pavarino-Bertelli, E.C.;Goloni-Bertollo, E.M.;
Brazilian Journal of Medical and Biological Research , 2010, DOI: 10.1590/S0100-879X2010007500034
Abstract: the functional effect of the a>g transition at position 2756 on the mtr gene (5-methyltetrahydrofolate-homocysteine methyltransferase), involved in folate metabolism, may be a risk factor for head and neck squamous cell carcinoma (hnscc). the frequency of mtr a2756g (rs1805087) polymorphism was compared between hnscc patients and individuals without history of neoplasias. the association of this polymorphism with clinical histopathological parameters was evaluated. a total of 705 individuals were included in the study. the polymerase chain reaction-restriction fragment length polymorphism technique was used to genotype the polymorphism. for statistical analysis, the chi-square test (univariate analysis) was used for comparisons between groups and multiple logistic regression (multivariate analysis) was used for interactions between the polymorphism and risk factors and clinical histopathological parameters. using univariate analysis, the results did not show significant differences in allelic or genotypic distributions. multivariable analysis showed that tobacco and alcohol consumption (p < 0.05), ag genotype (p = 0.019) and g allele (p = 0.028) may be predictors of the disease and a higher frequency of the g polymorphic allele was detected in men with hnscc compared to male controls (p = 0.008). the analysis of polymorphism regarding clinical histopathological parameters did not show any association with the primary site, aggressiveness, lymph node involvement or extension of the tumor. in conclusion, our data provide evidence that supports an association between the polymorphism and the risk of hnscc.
Polimorfismos GSTT1 e GSTM1 em indivíduos tabagistas com carcinoma espinocelular de cabe?a e pesco?o
Biselli, Joice Matos;Leal, Renata Cristina de Angelo Calsaverini;Ruiz, Mariangela Torreglosa;Goloni-Bertollo, Eny Maria;Maníglia, José Victor;Rossit, Andréa Regina Baptista;Pavarino-Bertelli, érika Cristina;
Revista Brasileira de Otorrinolaringologia , 2006, DOI: 10.1590/S0034-72992006000500012
Abstract: gene variability related to carcinogen activation and detoxification may interfere with susceptibility to head and neck cancer. aim: to investigate the relation between gstt1 and gstm1 null polymorphisms and the risk of head and neck squamous cell carcinoma in cigarette smokers. material and method: a case-control study conducted at the sao jose do rio preto medical school, brazil. gstm1 and gstt1 null genotype frequencies were evaluated by multiplex pcr in 45 cigarette smokers with head and neck squamous cell carcinomas and 45 cigarette smokers without this disease. results: the oral cavity was the most prevalent tumor site for squamous cell carcinoma. the gstt1 null genotype was found in 33.3% of the experimental group and 23.3% of the control group (p= 0.311). experimental and control groups had gstm1 null genotype frequencies of 35% and 48.3% (p=0.582). no association between alcohol consumption and gstt1 and gstmi null genotypes was found in these groups (p-values>0.05). there were more men, and alcohol consumption was prevalent in both groups. conclusion: in this study we were unable to show a correlation between gstm1 and gstt1 genotypes and the development of head and neck squamous cell carcinomas in cigarette smokers.
Methylenetetrahydrofolate reductase gene polymorphism and its association with coronary artery disease
Guerzoni, Alexandre Rodrigues;Pavarino-Bertelli, érika Cristina;Godoy, Moacir Fernandes de;Gra?a, Carla Renata;Biselli, Patrícia Matos;Souza, Dorotéia Rossi Silva;Bertollo, Eny Maria Goloni;
Sao Paulo Medical Journal , 2007, DOI: 10.1590/S1516-31802007000100002
Abstract: context and objective: obstructive coronary artery disease (cad) is characterized by the deposition of atherosclerotic plaque on the coronary artery wall. its manifestations depend on interactions between environmental and genetic risk factors. the aim of this work was to analyze the frequency of methylenetetrahydrofolate reductase (mthfr) c677t polymorphism in patients with cad and its association with plasma homocysteine levels. risk factors for cad were also evaluated. design and setting: retrospective with blind quantitative analysis, at hospital de base, faculdade de medicina de s?o josé do rio preto. methods: one hundred and twenty-seven individuals were studied. all completed a questionnaire to analyze risk factors for cad. mthfr polymorphism was investigated by restriction fragment length analysis and correlated with the number of affected arteries and degree of arterial obstruction determined by coronary cineangiography, and with plasma homocysteine levels measured by liquid chromatography/sequential mass spectrometry. results: smoking (p = 0.02) and high-density lipoprotein cholesterol (p = 0.01) were associated with cad. the c allele was the most prevalent in patients (0.61) and controls (0.66). there was no correlation between mthfr/c677t polymorphism and plasma homocysteine levels. however, in patients with the tt genotype there was a correlation with the prevalence of coronary obstruction greater than 95% (p = 0.02) and the presence of two affected arteries (p = 0.04). conclusions: the tt genotype is associated with coronary artery obstruction greater than 95% and the presence of two affected arteries. this confirms the relationship between genetic variants in specific patient subgroups and cardiovascular diseases.
Page 1 /461790
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.