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Search Results: 1 - 10 of 264041 matches for " Raphael C. Silva "
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Hepatocellular Carcinoma: Risk Factors, Diagnosis, Staging and Treatment in a Referral Centre  [PDF]
Raphael Raphe, Willian J. Duca, Paulo C. Arroyo Jr., Rita C. da Silva, Renato F. da Silva
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.42A046

Introduction: Hepatocellular carcinoma is the most common primary neoplasm of the liver and a significant cause of mortality in patients with cirrhosis. A retrospective cross-sectional study was performed to analyze epidemiological aspects related to risk factors, diagnosis, staging and first-line treatment in a closed population. Methods: The medical records of patients seen between November 1998 and May 2011 were revisited. Results: Of the 272 patients included in this study, 229 (84.2%) were male and the average age was 57.1 years (standard deviation 10.9 years). The most common etiology was hepatitis C virus infection in 145 (55.1%) patients, with this being the single cause in 88 (33.4%) patients. The largest masses ranged from 6 mm to 260 mm in diameter with a mean of 61.4 mm (standard deviation 41.5 mm). Only one mass was found in 145 (64.2%) cases, two masses in 26 (11.5%), three masses in 9 (4%) and 46 patients (20.3%) had multifocal disease. Early stage disease was diagnosed in 47 patients (22.0%), advanced stage in 65 (30.4%) and terminal stage in 32 (14.9%). Hepatocellular carcinoma was found by chance in 11%. Diagnosis was by means of imaging in 175 (68.1%) cases. The level of alpha-fetoprotein was measured in 209 patients, with 29.2% having levels lower than 20 ng/mL and 34.9% having levels above 400 ng/mL. Specific treatment was administered in 236 patients (86.8%) with hepatic chemoembolization in 127 (46.7%) and liver transplantation in 72 (26.5%); of these 33 (45.8%) received hepatic chemoembolization as a bridge to transplantation. Thirty-four patients (12.5%) received only supportive therapy. Conclusions: Patients are chiefly male and disease involvement generally occurs in the 5th decade of life. Cirrhosis was present in most patients and hepatitis

Case of Advanced Recurrent Glioblastoma Successfully Treated with Monoterpene Perillyl Alcohol by Intranasal Administration  [PDF]
C. O. Da Fonseca, Raphael M. Teixeira, Ricardo Ramina, Giovana Kovaleski, Júlio Thome Silva, Janaína Nagel, Thereza Quirico-Santos
Journal of Cancer Therapy (JCT) , 2011, DOI: 10.4236/jct.2011.21003
Abstract: We report a case of recurrent glioblastoma (GBM) successfully treated with the Ras inhibitor monoterpene perillyl alcohol by intranasal administration. A 37-years-old white woman had been previously submitted to three neurosurgical procedures, in June 2000 for radical tumor excision of grade II astrocytoma; in July 2003 for first recurrence of type IV glioma and in August 2004 for GBM recurrence. After last surgery, patient started a new cycle of chemotherapy but was refractory to treatment, presented clinical adverse effects and resonance image scan showed no reduction of tumoral lesion. Patient was then considered out of therapeutic possibilities and indicated for supportive treatment. On March 2005 patient joined Phase I/II clinical trial for assess the efficacy of the monoterpene POH, a Ras inhibitor. POH was administered by intranasal route four times a day (268 mg daily) as single chemotherapy agent. Image scans performed 3 and 5 years later revealed marked reduction of enhancing lesion. This illustrative case demonstrates that intranasal administration of the monoterpene POH as a single agent was an effective therapeutic strategy capable to sustain long-term regression of recurrent glioma without clinical and laboratory toxicity.
Caracteriza o dendrométrica de plantios de paricá (Schizolobium amazonicum Huber ex. Ducke) na regi o de Paragominas, PA Dendrometric characterization in paricá plantations (Schizolobium amazonicum Huber ex. Ducke) in the region of Paragominas, Pará, Brazil
Raphael G. Hoffmann,Gilson F. da Silva,José Franklim Chichorro,Rinaldo L. C. Ferreira
Revista Brasileira de Ciências Agrárias , 2011, DOI: 10.5039/agraria.v6i4a1039
Abstract: O objetivo deste trabalho foi avaliar as principais características dendrométricas como o diametro, a altura e a forma e avaliar modelos para estimar o volume total de árvores de paricá (Schizolobium amazonicum Huber ex. Ducke) em plantios comerciais com idades de cinco, seis e sete anos, em espa amento 4 x 4 m, na regi o de Paragominas, PA. A sele o dos modelos tomou como base medidas de qualidade de ajuste, como R2, erro padr o das estimativas, bem como a análise gráfica dos resíduos. Em rela o às características dendrométricas, os resultados obtidos mostraram que o paricá apresentou medidas dendrométricas semelhantes quando comparado ao eucalipto em condi es parecidas. A paricá teve um crescimento tanto em diametro quanto em altura semelhante a espécies de rápido crescimento. Quanto às equa es de volume total, de modo geral, o modelo de Schumacher e Hall apresentou estimativas mais precisas na estima o do volume das árvores. The aim of this study was to evaluate the main dendrometric characteristics of paricá (Schizolobium amazonicum Huber ex. Ducke), such as diameter, height and form, and also test models to estimate the total volume of paricá trees in commercial plantations with five, six and seven years of age, in a 4 m x 4 m spacing, in the region of Paragominas, Pará, Brazil. The models selection was based on goodness-of-fit indicators, such as R2, standard error of estimates, as well as the residual graphical analysis. Regarding the dendrometrical characteristics, results showed that the paricá trees presented similar dendrometrical measures when compared to eucalyptus in similar conditions. The paricá had a similar growth in both diameter and height to fast-growth species. As for the equations of total volume, generally, Schumacher and Hall’s model showed the best results to estimate the individual tree volume.
Comparing stochastic optimization methods to solve the medium-term operation planning problem
Gon?alves, Raphael E. C.;Finardi, Erlon C.;Silva, Edson L. da;Santos, Marcelo L. L. dos;
Computational & Applied Mathematics , 2011, DOI: 10.1590/S1807-03022011000200003
Abstract: the medium-term operation planning (mtop) of hydrothermal systems aims to define the generation for each power plant, minimizing the expected operating cost over the planning horizon. mathematically, this task can be characterized as a linear, stochastic, large-scale problem which requires the application of suitable optimization tools. to solve this problem, this paper proposes to use the nested decomposition, frequently used to solve similar problems (as in brazilian case), and progressive hedging, an alternative method, which has interesting features that make it promising to address this problem. to make a comparative analysis between these two methods with respect to the quality of the solution and the computational burden, a benchmark is established, which is obtained by solving a single linear programming problem (the deterministic equivalent problem). an application considering a hydrothermal system is carried out.
Dynamics of the Leaf-Litter Arthropod Fauna Following Fire in a Neotropical Woodland Savanna
Heraldo L. Vasconcelos,Renata Pacheco,Raphael C. Silva,Pedro B. Vasconcelos,Cauê T. Lopes,Alan N. Costa,Emilio M. Bruna
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0007762
Abstract: Fire is an important agent of disturbance in tropical savannas, but relatively few studies have analyzed how soil-and-litter dwelling arthropods respond to fire disturbance despite the critical role these organisms play in nutrient cycling and other biogeochemical processes. Following the incursion of a fire into a woodland savanna ecological reserve in Central Brazil, we monitored the dynamics of litter-arthropod populations for nearly two years in one burned and one unburned area of the reserve. We also performed a reciprocal transplant experiment to determine the effects of fire and litter type on the dynamics of litter colonization by arthropods. Overall arthropod abundance, the abundance of individual taxa, the richness of taxonomic groups, and the species richness of individual taxa (Formiciade) were lower in the burned site. However, both the ordinal-level composition of the litter arthropod fauna and the species-level composition of the litter ant fauna were not dramatically different in the burned and unburned sites. There is evidence that seasonality of rainfall interacts with fire, as differences in arthropod abundance and diversity were more pronounced in the dry than in the wet season. For many taxa the differences in abundance between burned and unburned sites were maintained even when controlling for litter availability and quality. In contrast, differences in abundance for Collembola, Formicidae, and Thysanoptera were only detected in the unmanipulated samples, which had a lower amount of litter in the burned than in the unburned site throughout most of our study period. Together these results suggest that arthropod density declines in fire-disturbed areas as a result of direct mortality, diminished resources (i.e., reduced litter cover) and less favorable microclimate (i.e., increased litter desiccation due to reduction in tree cover). Although these effects were transitory, there is evidence that the increasingly prevalent fire return interval of only 1–2 years may jeopardize the long-term conservation of litter arthropod communities.
Impactos Ambientais das Atividades Agrícolas em Roraima. = Environmental Impacts of Agriculture Activity in Roraima State.
Valdinar Ferreira Melo,Sandra Cátia Pereira Uch?a,Raphael H. S. Siqueira,Dianair F. da Silva
Agro@mbiente On-line , 2008,
Abstract: A agricultura foi a grande responsável pelo processo de coloniza o do Brasil. No entanto, estas atividades se desenvolveram ás expensas de a es negativamente impactantes ao meio ambiente. Este trabalho tem com objetivo abordar os impactos ambientais causados pela atividade agrícola no estado de Roraima, despertando o interesse da comunidade para o uso de uma agricultura fundamentada no conceito de sustentabilidade. A prática agropecuária no Brasil, inicialmente de forma empírica, sem muito conhecimento e preocupa o com seus efeitos no ambiente, causou a dizima o de grande parte das florestas e a biodiversidade, mas, também, possibilitou a ocupa o da terra e a defini o dos limites territoriais brasileiros, definindo-se como de grande importancia para a sustenta o da economia, imprimindo ao Brasil sua voca o agrícola. A atividade nos anos 60 foi concebida para a valida o de pacotes tecnológicos importados, contribuiu para a execu o de práticas socialmente excludentes e ambientalmente danosas, com reflexos positivos na produ o agrícola e comércio de insumos, à custa da implanta o de sistemas monoculturais, com motomecaniza o, irriga o e emprego intensivo de fertilizantes químicos e pesticidas. A impropriedade ambiental deste modelo originou movimentos que culminaram com a conscientiza o para estas quest es, tendo como respostas a elabora o de instrumentos técnicos e jurídicos, e formula o de propostas para avaliar e mitigar os impactos ambientais e modificar as a es humanas, tornando-as mais condizentes com novos paradigmas da sociedade. Em Roraima, esta atividade sofre uma nova mudan a, onde as técnicas primitivas de explora o agrícola come am a ser substituídas por atividades tecnificadas com o uso intensivo de tecnologias, com risco de improbidade ambiental que pode culminar com a degrada o do meio, caso n o haja uma perícia profunda das características ambientais sem negligenciar as técnicas e resultados de pesquisas que possibilitam o desenvolvimento sustentável do ambiente. = The agriculture was the great responsible for the colonization process of Brazil. However, these activities grew with negatively impacts to the environment. The objective of this work are to approach the environmental impacts caused by the agricultural activity in Roraima state, waking up the community's interest for the use of an agriculture based on the sustainability concept. The agricultural practice in Brazil, initially in an empiric way, without much knowledge and concern with their effects in the environment, it caused the decimation of great part of fo
Specificity and selectivity improvement in doping analysis using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry
Barbosa, Samantha S.;Leal, Felipe D.;Padilha, Monica C.;Silva, Raphael S. F.;Pereira, Henrique Marcelo G.;Aquino Neto, Francisco R.;Silva Júnior, Ademário I. da;
Química Nova , 2012, DOI: 10.1590/S0100-40422012000500022
Abstract: comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry was used for the identification of forty doping agents. the improvement in the specificity was remarkable, allowing the resolution of analytes that could not be done by one-dimensional chromatographic systems. the sensitivity observed for different classes of prohibited substances was clearly below the value required by the world anti-doping agency. in addition time-of-flight mass spectrometry gives full spectrum for all analytes without any interference from the matrix, resulting in selectivity improvements. these results could support the implementation of an exhaustive monitoring approach for hundreds of doping agents in a single injection.
Interplay between spin-density-wave and superconducting states in quasi-one-dimensional conductors
Raphael Duprat,C. Bourbonnais
Physics , 2001, DOI: 10.1007/s100510170198
Abstract: The interference between spin-density-wave and superconducting instabilities in quasi-one-dimensional correlated metals is analyzed using the renormalization group method. At the one-loop level, we show how the interference leads to a continuous crossover from a spin-density-wave state to unconventional superconductivity when deviations from perfect nesting of the Fermi surface exceed a critical value. Singlet pairing between electrons on neighboring stacks is found to be the most favorable symmetry for superconductivity. The consequences of non uniform spin-density-wave pairing on the structure of phase diagram within the crossover region is also discussed.
Opportunistic screening for skin cancer using a mobile unit in Brazil
Edmundo C Mauad, Thiago B Silva, Maria RDO Latorre, René AC Vieira, Raphael L Haikel, Vinicius L Vazquez, Adhemar Longatto-Filho
BMC Dermatology , 2011, DOI: 10.1186/1471-5945-11-12
Abstract: The diagnosis of skin cancer was accomplished through active medical screening in the prevention Mobile Unit (MU) of Barretos Cancer Hospital (BCH). The study population consisted of patients examined in the MU between 2004 and 2007, and their suspicious lesions were subjected to histopathological evaluation. Data were collected prospectively from standardized forms and analyzed.During the screening, 17,857 consultations were carried out. A total of 2012 (11.2%) cases of skin cancer were diagnosed. The predominant histological type reported was basal cell carcinoma (n = 1,642 or 81.6%), followed by squamous cell carcinoma (n = 303 or 15.1%), Bowen's disease (n = 25 or 1.2%), malignant melanoma (n = 23 or 1.1%), basosquamous cell carcinoma (n = 3 or 0.1%), miscellaneous lesions (12 or 0.6%), and metatypical carcinoma (n = 4 or 0.2%). Only 0.6% of lesions were stage III. There were no stage IV non-melanoma skin lesions, as well as no melanomas stages III and IV, found.It was observed that the MU can be a useful tool for early skin cancer diagnosis and treatment. This program probably is important, especially in developing countries with inadequate public health systems and social inequality.Skin cancer is the most common malignancy in the white population worldwide[1]. The 2 most common histopathological variants are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC); despite their low mortality rates, these tumors can induce serious sequelae as a consequence of surgery[1]. The third most common skin cancer type, malignant melanoma, has a more aggressive behavior and consequently a poorer prognosis; malignant melanoma accounts for approximately 75% of all deaths from skin cancer[2].There is strong evidence to date that whole-body clinical skin examination reduces the incidence of thick melanoma and, consequently, screening would reduce melanoma mortality[3]. Melanoma thickness at presentation is significantly associated with educational level[4]. In Brazil,
Comprehensive two-dimensional gas chromatography with time of flight mass spectrometry applied to analysis of Fischer-Tropsch synthesis products obtained with and without carbon dioxide addition to feed gas
Silva, Raphael S. F.;Tamanqueira, Juliana B.;Dias, Julio César M.;Passarelli, Fábio M.;Bidart, Antonio Marcos F.;Aquino Neto, Francisco R.;Azevedo, Débora A.;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011001100015
Abstract: comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (gc × gc-tofms) was applied to evaluate the co2 effect on distribution of n-alkanes, branched alkanes, alkenes and oxygen-containing compounds in fischer-tropsch products. gc × gc-tofms was able to resolve the unresolved compounds observed in conventional gc.
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