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Search Results: 1 - 10 of 320369 matches for " R. O. Pires "
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Low frequency fields driven by the Ergodic Magnetic Limiter at rational surfaces in rotating tokamak plasmas
Rondán, E. R.;Elfimov, A. G.;Galv?o, R. M. O.;Pires, C. J. A.;
Brazilian Journal of Physics , 2004, DOI: 10.1590/S0103-97332004000800031
Abstract: the rotating low frequency (rlf) field penetration and dissipation and the effect of ponderomotive forces driven by ergodic magnetic limiter (eml) on the poloidal/ toroidal flow in tokamak plasmas are discussed. eml coils are represented as a sheet current expanded in fourier series with poloidal/toroidal wave numbers m/n depending on coil shape and feeding. the alfvén wave mode conversion effect in the rlf range is found responsible for wave dissipation at the rational magnetic surfaces qr = -m/n = 3 typical for eml coil design. analytical and numerical calculations show maximums of lf field dissipation at the local alfvén wave resonance w = ?k||ca? near the rational magnetic surface qr = 3 in tokamak chauffage alfvén brésilien. the poloidal rotation velocity u, taken into account in the dielectric tensor, can strongly modify the lf field and dissipated power profiles. even stationary eml fields can dissipate at the local alfvén wave resonance (um/ra = k||ca). preliminary estimations show that the stationary eml fields can decelerate the plasma rotation.
Synthesis, structural and morphological characterization of CeO2-ZnO nanosized powder systems from Pechini's method
Peverari, C.;Pires, A. M.;Gon?alves, R. R.;Serra, O. A.;
Eclética Química , 2005, DOI: 10.1590/S0100-46702005000100008
Abstract: this work reports on the investigation of nanosized ceo2-zno systems prepared by pechini's method. the structural and morphological characterization of ceo2-zno systems as well as the characterization of ceo2 and zno separately, showed that the employed method result in powders with spheroidal particles whose size are in the range 30 - 200 nm, which is appropriate to provide homogeneous suspensions. the zno present in the prepared mixed oxides seems to increase particle size distribution and to influence the arrangement of the particles after powder dispersion.
Algae of economic importance that accumulate cadmium and lead: a review
Priscila O. Souza,Lizangela R. Ferreira,Natanael R. X. Pires,Pedro J. S. Filho
Revista Brasileira de Farmacognosia , 2012,
Abstract: Currently, algae and algae products are extensively applied in the pharmaceutical, cosmetic and food industries. Algae are the main organisms that take up and store heavy metals. Therefore, the use of compounds derived from algae by the pharmaceutical industry should be closely monitored for possible contamination. The pollution generated by heavy metals released by industrial and domestic sources causes serious changes in the aquatic ecosystem, resulting in a loss of biological diversity and a magnification and bioaccumulation of toxic agents in the food chain. Since algae are at the bottom of the aquatic food chain, they are the most important vector for transfer of pollution to upper levels of the trophic chain in aquatic environments. Moreover, microalgae are also used for the bioremediation of wastewater, a process that does not produce secondary pollution, that enables efficient recycling of nutrients and that generates biomass useful for the production of bioactive compounds and biofuel.
Ballistic ureteroscopic lithotripsy in prepubertal patients: a feasible option for ureteral stones
Fuganti, Paulo E.;Pires, Silvio R.;Branco, Renato O.;Porto, Jose L.;
International braz j urol , 2006, DOI: 10.1590/S1677-55382006000300013
Abstract: objective: to evaluate the role of ballistic ureteroscopic lithotripsy in children with ureteral stones. materials and methods: children under 14 years with ureteral stones were treated with ureteroscopy in a 5-year period in our institution. results: twenty-three procedures were performed in 20 children. mean surgical time, age and stone size were 31 min. (15 - 120min.), 11 years. (4-13 years), 5.3 mm (3-10 mm) respectively. three patients underwent two ballistic ureteroscopic lithotripsy each. there were 22 successful procedures (96%) and a 100% stone-free rate per patient. complications (mucosal tear) occurred in 2 procedures (8%) without extravasation of contrast media on retrograde pyelogram and their follow-up was uneventful. conclusion: ureteroscopic ballistic lithotripsy is a feasible option for ureteral stones in prepubertal patients, with high stone-free rate and few complications.
Crosslinked chitosan/poly (vinyl alcohol) blends with proton conductivity characteristic
Witt, M. A;Barra, G. M. O;Bertolino, J. R;Pires, A. T. N;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000900014
Abstract: chitosan is a polymer which is easily obtained from the deacetylation of chitin, the second most abundant natural polymer. it offers attractive chemical and physical properties, including those required to obtain membranes. in this study, chitosan in chloridric acid solution was chemically modified with sulfosuccinic acid (ssa), which acts as a crosslinking agent and proton donor. the chloridric acid medium promotes the crosslinking reaction through inducing the protonation of free carboxyl groups. the membrane was obtained through casting of poly (vinyl alcohol) (pval) and chitosan-ssa solution. the influence of the ssa content on the crosslinking degree of the chitosan was evaluated through ftir analysis. the ion exchange capacity (iec) and water absorption values were also related to the ssa content in the systems. the physicochemical characteristics, such as the proton and electrical conductivity values, indicated the viability of the utilization of these materials as polymer electrolyte membranes (pem) in fuel cells.
Efeitos de concentra??es crescentes de lidocaína hiperbárica, administradas no espa?o subaracnóideo, sobre a medula espinhal e as meninges: estudo experimental em c?es
Pires, Silvania R.O.;Ganem, Eliana Marisa;Marques, Mariangela;Castiglia, Yara Marcondes Machado;
Revista Brasileira de Anestesiologia , 2006, DOI: 10.1590/S0034-70942006000300005
Abstract: background and objectives: lidocaine concentration potentially able to determine nervous tissue injury is still not well established. this study aimed at investigating the effect of increasing spinal lidocaine concentrations in single injection through quincke needle. methods: after the animal experiment ethical committee approval, 40 adult animals were anesthetized with fentanyl and etomidate and submitted to spinal puncture with 22g 21/2 quincke needle for the introduction of 1 ml of 7.5% glucose solution in 10 seconds - group 1; 5% lidocaine in 7.5% glucose solution - group 2; 7.5% lidocaine in 7.5% glucose solution - group 3; 10% lidocaine in 7.5% glucose solution - group 4. after intravenous anesthesia recovery and in the presence of spinal block, the following parameters were observed: presence of motor block, anal sphincter tone (normal or relaxed) and sensory block level in different cervical, thoracic, lumbar and sacral dermatomes. animals remained in captivity for 72 hours. anal sphincter tone, hind paws mobility, painful fore and hind paws and sacral, lumbar and thoracic dermatomes sensitivity were evaluated. were euthanized by electrocution under anesthesia and spinal cord and meningeal lumbar and sacral portions were removed for histological exam under optic microscopy. results: no group 1 and 2 animal presented clinical or histological injuries. three group 3 animals presented hind paws motor changes and anal sphincter relaxation with foci of posterior necrosis (two dogs) and fascial necrosis in all spinal cord surface (one dog). in a different animal of this group in which foci of necrosis were observed in less than 5% histological field, no clinical changes were found. seven group 4 animals presented clinical changes (paralysis or decreased muscle strength in hind paws, anal sphincter relaxation) or histological changes (spinal cord surface band necrosis or nervous tissue necrosis foci). conclusions: in this study, spinal lidocaine in concentrations
Aplica??o da poliacrilamida no controlo da eros?o e do escoamento superficial na rega por rampa rotativa
Pires,R. O.; Reis,J. L.; Santos,F. L.; Castanheira,N. L.;
Revista de Ciências Agrárias , 2007,
Abstract: polyacrylamide was applied to several soils through a center pivot irrigation system to study their effects on erosion and runoff control. tests were designed to apply the polyacrylamide to vt, a, bvc and pmg portuguese soils, and under two slopes, 2,5 and 5% respectively. each soil was submitted to five irrigations, being the polyacrylamide applied on the following criteria: 1) one single application with the first irrigation at a concentration of 7 ppm (0,84 kg/ha), 2) two applications, first and second irrigation, at a concentration of 3,5 ppm (0,42 kg/ha each, and a total of 0,84 kg/ha), 3) three aplications, first, second and third irrigation, at a concentration of 2,33 ppm (0,28 kg/ha each, and a total of 0,84 kg/ha. the rates applied seem to better control erosion and runoff on soil a, being the best results obtained when the polyacrylamide was applied twice, in the first and second irrigation. on soil vt the results are not so conspicuous, but the multi applications (three times) of polyacrylamide seem to provide some protection to soil against erosion. the same can be observed for soil pmg. soil bvc does not require polyacrylamide applications to control erosion and runoff.
Aplica o da poliacrilamida no controlo da eros o e do escoamento superficial na rega por rampa rotativa Polyacrylamide application in center pivot irrigation systems for erosion and runoff control
R. O. Pires,J. L. Reis,F. L. Santos,N. L. Castanheira
Revista de Ciências Agrárias , 2007,
Abstract: Na rega por rampa rotativa geralmente a intensidade de precipita o da água aplicada ultrapassa a taxa de infiltra o, o que vai gerar escoamento superficial e arrastamento de partículas do solo que, além do favorecimento de perda de solo, aumenta também os riscos de polui o das linhas de água e albufeiras. O presente trabalho foi realizado com o objectivo de, numa primeira aproxima o, estudar estratégias de aplica o da poliacrilamida aniónica (PAM), um condicionador de solo, para o melhor controlo da eros o e escoamento superficial de vários solos do Alentejo regados por rampa rotativa. Delineou-se um conjunto de testes para a recolha de dados para análise, tendo-se em conta os tipos de solos e dois declives préestabelecidos. Assim procedeu-se à instala o do ensaio experimental na Herdade da Mitra, utilizando-se uma rampa rotativa experimental e aplicou-se com dois declives, de 2,5% e 5%, a poliacrilamida aos solos Vt, A, Bvc e Pmg. A cada solo aplicou-se cinco regas, tendo a PAM sido também aí aplicada com o seguinte critério: 1) de forma única na primeira rega com uma concentra o de 7 ppm, o que corresponde a uma taxa de aplica o de 0,84 kg/ha, 2) de forma fraccionada nas duas primeiras regas com uma concentra o de 3,5 ppm e uma taxa de aplica o de 0,42 kg/ha em ambas, num total de 0,84 kg/ha e 3) de forma fraccionada nas três primeiras regas com uma concentra o de 2,33 ppm e uma taxa de aplica o de 0,28 kg/ha em cada uma, num total de 0,84 kg/ha, tendo-se comparado todas estas aplica es de PAM com a testemunha (sem PAM). Para controlo das dota es de água aplicadas colocaram-se pluviómetros e udógrafos na área circundante a cada talh o, constituído por tabuleiros com os respectivos solos e em declives préestabelecidos. Procedeu-se à recolha da água de escorrimento e dos sedimentos arrastados. O aumento do declive por si só, aumenta o escoamento. Por cada tipo de solo, as diferentes modalidades de aplica o de poliacrilamida (PAM) tiveram um comportamento diferente mas irregular em termos de redu o de escoamento superficial e da eros o. Existem indícios que mostram que a aplica o de PAM é benéfica, em especial no solo A, para o controlo desses parametros. No solo Vt, com os testes efectuados é difícil tra ar uma estratégia de aplica o de PAM. De qualquer forma, a aplica o fraccionada em três vezes na eros o foi melhor que nas outras aplica es, embora no escoamento superficial isso n o se verifique, aconselhando-se ainda assim esta modalidade. Quanto ao solo A, constatou-se que a aplica o de PAM fraccionada em duas vezes, foi a que obt
In u ancia da retirada da casca na digestibilidade proteica de feij £o vermelho e de soja utilizando o m todo in vitro
In uence of bark extraction of protein digestibility of red beans and soybeans using the in vitro method

Alimentos e Nutri??o , 2011,
Abstract: As prote -nas s £o compostos org ¢nicos complexos, fundamentais aos organismos animal e humano, que t am como principal fun § £o na dieta suprir o organismo de amino cidos indispens veis em quantidades adequadas para s -ntese e manuten § £o dos tecidos corporais. A determina § £o da digestibilidade proteica de um alimento um fator importante para estimar a sua qualidade, sendo o m todo in vitro uma alternativa r pida e f cil. A baixa digestibilidade dos gr £os atribu -da a fatores antinutricionais que diminuem a atividade das enzimas digestivas. O objetivo deste trabalho foi determinar a digestibilidade proteica in vitro de prote -na de gr £os de soja e feij μes, integrais e sem casca, veri cando assim se esta interfere na digestibilidade. Veri cou-se que a retirada da casca dos gr £os interferiu na digestibilidade in vitro.
Efeitos de concentra es crescentes de lidocaína hiperbárica, administradas no espa o subaracnóideo, sobre a medula espinhal e as meninges: estudo experimental em c es
Pires Silvania R.O.,Ganem Eliana Marisa,Marques Mariangela,Castiglia Yara Marcondes Machado
Revista Brasileira de Anestesiologia , 2006,
Abstract: JUSTIFICATIVA E OBJETIVOS: Ainda n o está bem estabelecida a concentra o de lidocaína que é potencialmente capaz de determinar les o no tecido nervoso. O objetivo desta pesquisa foi estudar os efeitos sobre a medula espinhal e as meninges, de concentra es crescentes de lidocaína administrada por via subaracnóidea, em inje o única através de agulha de Quincke. MéTODO: Após a aprova o da Comiss o de ética em Experimenta o Animal, 40 c es adultos foram anestesiados com fentanil e etomidato e submetidos a pun o subaracnóidea com agulha de Quincke 22G 21/2 para introdu o de 1 mL, em 10 segundos, de solu o glicosada a 7,5% - Grupo 1; lidocaína a 5% em solu o glicosada a 7,5% - Grupo 2; lidocaína a 7,5% em solu o glicosada a 7,5% - Grupo 3; lidocaína a 10% em solu o glicosada a 7,5% - Grupo 4. Após a recupera o da anestesia venosa, foram observados, no período em que os animais estavam em vigência do bloqueio subaracnóideo, a presen a de bloqueio motor, o t nus do esfíncter anal (normal ou relaxado) e o nível de bloqueio sensitivo nos diferentes dermátomos das regi es cervical, torácica, lombar e sacral. Os animais permaneceram em cativeiro por 72 horas. Foram avaliados o t nus do esfíncter anal, a motricidade das patas posteriores, a sensibilidade dolorosa nas patas anteriores e posteriores e nos dermátomos sacrais, lombares e torácicos. Após serem sacrificados por eletrocuss o sob anestesia, foram retiradas por es lombar e sacral da medula espinhal e das meninges para exame histológico por microscopia óptica. RESULTADOS: Nenhum animal dos Grupos 1 e 2 apresentou les es clínicas ou histológicas. Três animais do Grupo 3 apresentaram altera es motoras nas patas posteriores e relaxamento do esfíncter anal. Nestes, foram observados focos de necrose na regi o posterior (dois c es) e necrose em faixa em toda a superfície medular (um c o). Em um outro animal deste grupo, no qual foram notados focos de necrose, em área inferior a 5% do campo histológico n o foram encontradas altera es clínicas. Sete animais do Grupo 4 apresentaram altera es clínicas (paralisia ou diminui o de for a muscular nas patas posteriores, relaxamento do esfíncter anal) e histológicas (necrose na faixa da superfície medular ou focos de necrose de tecido nervoso). CONCLUS ES: Neste estudo, a lidocaína em concentra es superiores a 7,5%, em inje o única, administrada no espa o subaracnóideo por meio de agulha de Quincke, determinou altera es histológicas sobre a medula espinhal, mas n o sobre as meninges.
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