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Search Results: 1 - 10 of 327263 matches for " Sérgio;Assis "
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The effect of hydrogen peroxide on the electrochemical behaviour of Ti-13Nb-13Zr alloy in Hanks' solution
Assis, Sérgio Luiz de;Costa, Isolda;
Materials Research , 2006, DOI: 10.1590/S1516-14392006000400014
Abstract: titanium alloys are largely used for biomedical applications mainly due to their high corrosion resistance resulting from the protective oxide film formed on their surface. the literature, however, has pointed out discrepancies between in vitro tests and in vivo tests. these discrepancies have been ascribed to hydrogen peroxide (h2o2) generated by inflammatory reactions. in this investigation the electrochemical behaviour of a ti-13nb-13zr alloy, which was developed as material for implants, has been evaluated in hanks' solution, with and without h2o2. the evolution of the electrochemical behavior was monitored by electrochemical impedance spectroscopy (eis) and the results were fitted to an equivalent circuit that simulates an oxide film as a duplex layer structure composed of an inner barrier layer and an outer porous layer. in the solution without h2o2, the oxide film was very stable during the whole test period. on the other hand, in the solution with h2o2, the eis results varied significantly, indicating a progressive decrease in the barrier layer resistance until 35 days which was followed by the restoration of the barrier layer protective characteristics against corrosion, either due to its growth or to its self-healing after partial consumption of the oxidant agent. the oxide film formed on the ti alloy samples after 125 days of immersion in hanks' solution, either with or without h2o2 was analyzed by xps. the xps results revealed the presence of tio and tio2 on the samples immersed in the two electrolytes, however, ti2o3 was only found on the samples exposed to the h2o2 containing solution.
The effect of polarisation on the electrochemical behavior of Ti-13Nb-13Zr alloy
Assis, Sérgio Luiz de;Costa, Isolda;
Materials Research , 2007, DOI: 10.1590/S1516-14392007000300014
Abstract: the effect of potentiostatic polarisation on the electrochemical behavior of the ti-13nb-13zr alloy was investigated by electrochemical impedance spectroscopy (eis) and potentiodynamic polarisation curves in hanks' solution at 37 °c. potentiodynamic polarisation curves show a passive behavior with a slight current increase as potentials around 1300 mv(sce). based on these curves, different potentials were chosen to perform potentiostatic eis experiments. eis experimental data were interpreted using different equivalent circuits associated with the duplex nature of the oxide layer. the fitting procedure evidenced the thickening of a defective oxide layer with the applied potentials, corresponding to key points in the potentiodynamic polarisation curves.
Sexualidade, cultura e política: a trajetória da identidade homossexual masculina na antropologia brasileira
Carrara, Sérgio;Sim?es, Júlio Assis;
Cadernos Pagu , 2007, DOI: 10.1590/S0104-83332007000100005
Abstract: our aim is to inquire into the ways in which a presumed brazilian "managing" of sexual categories or identities (mainly related to male homosexuality) has been conceived in anthropology since the end of the 1970, sometimes becoming an axis for building and maintaining a national identity characterized as exotic, backward and not pertaining to "the west". we also parallel two moments in the reflection about the links between sexuality, culture and politics, briefly reviewing some of early theoretical and empirical contributions that prefigure central concerns and conceptualizations in present sexuality studies which are related to instability and fluidity of sexual identities, as well as to the entanglement of sexuality with dynamic and contextual power relationships and social hierarchies.
Estudo de correla??o entre provas funcionais respiratórias e o teste de caminhada de seis minutos em pacientes portadores de doen?a pulmonar obstrutiva cr?nica
Jornal de Pneumologia , 2002, DOI: 10.1590/S0102-35862002000600005
Abstract: introduction: spirometry and analysis of blood gases data have been extensively used to assess ventilatory limitation and prognosis of copd patients. however, functional physical tests, such as the six-minute walk test (6wt) have been used for the dynamic assessment of copd patients. objective: to determine correlations between respiratory function test data and the six-minute walk test in copd patients. patients and methods: 45 patients were submitted to clinical history survey and complete physical examination performed by the medical staff of the pneumology department of the brasilia university hospital, followed by spirometry, analysis of arterial blood gases, maximal respiratory pressures data, and the six-minute walk test. results: concerning the spirometric, analysis of blood gases and maximal respiratory pressures data, statistically significant positive correlations (p < 0.05) between fev1, pao2, spo2, mep and the six-minute walk test were obtained. conclusions: for the studied group, the six minute walk test has significant correlation with fev1, pao2, spo2 and mep, and can be used as an alternative functional assessment of copd patients.
Estudo de correla o entre provas funcionais respiratórias e o teste de caminhada de seis minutos em pacientes portadores de doen a pulmonar obstrutiva cr nica
Jornal de Pneumologia , 2002,
Abstract: Introdu o: A espirometria e a gasometria s o largamente utilizadas na estimativa da limita o ventilatória e do prognóstico de pacientes portadores de doen a pulmonar obstrutiva cr nica. Entretanto, testes físicos funcionais, como o teste de caminhada de seis minutos (Tc6), têm surgido como complemento na avalia o dinamica de portadores de doen a pulmonar obstrutiva cr nica. Objetivo: Determinar as correla es entre as provas funcionais respiratórias e o teste de caminhada de seis minutos em portadores de DPOC. Pacientes e métodos: 45 pacientes foram submetidos à coleta de história clínica e a exame físico completo realizado pela equipe médica do Servi o de Pneumologia do Hospital Universitário de Brasília. Em seguida, foi realizada a avalia o das variáveis espirométricas, gasométricas, das press es respiratórias e o teste de caminhada de seis minutos (Tc6). Resultados: Observaram-se correla es positivas estatisticamente significativas (p < 0,05) das variáveis VEF1, PaO2, SpO2 e Pe máx em rela o ao teste de caminhada de seis minutos. Conclus es: O teste de caminhada de seis minutos correlacionou-se de forma significativa (p < 0,05) e positiva e pode ser utilizado como instrumento alternativo na avalia o funcional do paciente portador de DPOC.
Student responses to the introduction of case-based learning and practical activities into a theoretical obstetrics and gynaecology teaching programme
Júlio Massonetto, Cláudio Marcellini, Paulo Assis, Sérgio de Toledo
BMC Medical Education , 2004, DOI: 10.1186/1472-6920-4-26
Abstract: Small-group discussions of cases and practical activities were introduced for the teaching of a fourth-year class in 2003 (Group II; 113 students). Comparisons were made with the fourth-year class of 2002 (Group I; 108 students), from before the new programme was introduced. Students were asked to rate their satisfaction with various elements of the teaching programme. Statistical differences in their ratings were analysed using the chi-square and Bonferroni tests.Group II gave higher ratings to the clarity of theory classes and lecturers' teaching abilities (p < 0.05) and lecturers' punctuality (p < 0.001) than did Group I. Group II had greater belief that the knowledge assessment tests were useful (p < 0.001) and that their understanding of the subject was good (p < 0.001) than did Group I. Group II gave a higher overall rating to the course (p < 0.05) than did Group I. However, there was no difference in the groups' assessments of the use made of the timetabled hours available for the subject or lecturers' concern for students' learning.Students were very receptive to the new teaching model.In Brazil, medical school courses last for six years and demand full-time study. In our school, the curriculum follows the traditional model, and it is divided into the basic cycle (first and second years), clinical cycle (third and fourth years) and pre-intern cycle (fifth and sixth years; full-time outpatient and hospital practice).The practice of institutional self-evaluation, especially for educational institutions, has become part of the country's recent culture [1]. It has come about as a result of the democratic transition that Brazil went through from 1986 onwards and with the introduction of quality control principles in the past decade. In our school, we introduced an annual subject evaluation programme (SEP) in 2000, for the purposes of self-evaluation. Every year, in the middle of the second semester, all students in each year-group fill out a standard questionnair
Mobilidade de capitais e crescimento econ?mico: elementos para uma síntese teórica
Meyrelles Filho, Sérgio F.;Jayme Jr., Frederico Gonzaga;Libanio, Gilberto de Assis;
Economia e Sociedade , 2009, DOI: 10.1590/S0104-06182009000300001
Abstract: this paper aims at exploring theoretically the literature regarding capital flows liberalization and economic growth. precisely, we intend to analyze the role of capital controls over economic growth. mainstream literature discard capital controls as an alternative to foster economic growth, although admits, in few situations, temporarily quantitative capital controls to avoid financial crisis. the keynesian approach to economic growth by means of kaldorian literature is the key to understanding capital controls as an strategy to warrant growth under balance of payments equilibrium. conclusions highlight the role of capital controls in helping economic growth.
Estabelecimento de protocolo para multiplica??o in vitro de Bast?o-do-imperador (Etlingera elatior) Jack RM Sm.
Colombo, Larissa Abgariani;Assis, Adriane Marinho de;Faria, Ricardo Tadeu de;Roberto, Sérgio Ruffo;
Acta Scientiarum. Agronomy , 2010, DOI: 10.4025/actasciagron.v32i4.4830
Abstract: the objective of the present paper was to establish a protocol for in vitro multiplication of the philippine wax flower. axillary shoots were inoculated in ms medium, holding the following concentrations of plant growth regulators during the isolation stage: without plant growth regulator; benzylaminopurine(bap) 2.25 mg l-1; bap 2.25 mg l-1 + naphthaleneacetic acid (naa) 0.93 mg l-1; bap 2.25 mg l-1 + indoleacetic acid (iaa) 0.87 mg l-1; bap 4.95 mg l-1; bap 4.95 mg l-1 + naa 0.93 mg l-1; bap 4.95 mg l-1 + iaa 0.87 mg l-1 and shootings from this stage were cultivated in a new ms medium following different combinations of plant growth regulators: without plant growth regulator; bap 2.25 mg l-1; bap 3.37 mg l-1; bap 4.50 mg l-1; bap 2.25 mg l-1 + naa 1.12 mg l-1; bap 3.37 mg l-1 + naa 2.25 mg l-1; bap 4.50 mg l-1 + naa 3.37 mg l-1 and shooting multiplication rate per replicate was evaluated. the best treatment, during the isolation stage, was bap 4.95 mg l-1 + iaa 0.87 mg l-1. during the multiplication stage, there were three to four shootings per replicate, regardless of the concentrations and combinations of plant growth regulators used. the seedlings rooted, forming clusters on ms medium without plants growth regulators, resulting in eight to ten seedlings per cluster.
Teste de caminhada de seis minutos: estudo do efeito do aprendizado em portadores de doen?a pulmonar obstrutiva cr?nica
Rodrigues, Sérgio Leite;Mendes, Hélder Fonseca e;Viegas, Carlos Alberto de Assis;
Jornal Brasileiro de Pneumologia , 2004, DOI: 10.1590/S1806-37132004000200008
Abstract: background: the six minutes walk test has been increasingly utilized to assess the effectiveness of different clinical and surgical treatment options in pulmonary diseases. however lack of standardization for their performance may influence measurements and jeopardize assessment of the functional capacity of patients with cardiopulmonary disease. objective: to determine the possible effects of learning on the distance covered during the six minute walk test for bearers of chronic obstructive pulmonary disease. method: a retrospective analysis of 35 medical records of copd patients referred to the pulmonary rehabilitation program of the university hospital of brasìlia was carried out. on alternate days these patients had performed two six minutes walk tests, spirometry and arterial blood gas analysis. clinical and functional diagnosis was based upon the history of exposure to risk factors, mucus production, dyspnea and spirometric dysfunction after use of bronchodilators. the student test was used for the comparison of results that were different. results: the distances covered in the second six-minute walk test (515 ± 82 meters) were greater than those covered in the first six-minute walk test (480 ± 85 metros), with statistically significant differences (p<0.05). however measurements of the muscular effort and perception of dyspnea (borg scale), peripheral blood oxygen saturation (spo2), respiratory and heart rates did not disclose any statistically significant differences between the two tests (p<0.05). conclusion: the present study suggests that in order to standardize the six minutes walk test, the procedure should be performed at least twice to better assess the functional capacity of patients, bearers of chronic obstructive pulmonary disease.
Efetividade da reabilita??o pulmonar como tratamento coadjuvante da doen?a pulmonar obstrutiva cr?nica
Jornal de Pneumologia , 2002, DOI: 10.1590/S0102-35862002000200002
Abstract: introduction: the patient with copd has his global physical activity decreased due to a progressive worsening of the lung function resultant from any kind of physical effort he may perform. pulmonary rehabilitation (pr) is used in the united states and europe as an alternative therapy in copd treatment. objective: to evaluate the effectiveness of pr as an ancillary treatment for copd. patients and methods: 30 patients prospectively submitted to the pr program developed in six weeks with three weekly sessions. evaluation included clinical history and complete physical examination, the six-minute walking distance test, maximum workload test for upper limbs, maximum load test for lower limbs, a questionnaire of effort perception, spirometry and analysis of blood gases. results: concerning spirometry and analysis of blood gases, pre and post pr program, no statistically significant change was observed (p > 0.05). pre and post pr program, statistically significant values (p < 0.05) were observed in the decrease in effort perception and increase in functional physical capacity, maximum workload test for upper limbs and incremental test for lower limbs used to determine the maximum workload. conclusions: the authors concluded that, in the group studied, the pr program increased the patients' physical capacity and maximum workload for upper limbs whereas no changes were observed in the data regarding spirometry and analysis of blood gases.
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