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Search Results: 1 - 10 of 27931 matches for " Ricardo Geraldo Sousa "
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Multifunctional Nanostructured Materials Applied in Controlled Radiopharmaceuticals Release  [PDF]
Raquel Cristina de Sousa Azevedo, Daniel Crístian Ferreira Soares, Ricardo Geraldo de Sousa, Edésia Martins Barros de Sousa
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2012, DOI: 10.4236/jbnb.2012.32022
Abstract: The metaiodobenzylguanidine (MIBG) radiopharmaceutical, an analogue of norepinephrine, has been used to diagnose certain diseases in the cardiovascular system when radiolabeled with 123I. This radiopharmaceutical can also be used to treat tumors, such as neuroblastomas and pheochromocytomas, when radiolabeled with 131I. Its clinical use is often accompanied by a slow intravenous administration, where a significant dose of radiation can directly affect workers in nuclear medicine services. To overcome this problem, the incorporation and controlled release of radiopharmaceuticals from the matrix of mesoporous systems based on silica, such as SBA-15 and hybrid [SBA-15/P(N-iPAAm)], can lead to a significant reduction in radiation doses received by workers. In the present study, silica matrices SBA-15 and hybrid [SBA-15/P(N-iPAAm)] containing the radiopharmaceutical MIBG were prepared and physicochemically characterized through FTIR, SEM, and small angle X-ray diffraction techniques. The release profiles of MIBG from SBA-15 and [SBA-15/P(N-iPAAm)] were studied in a simulated body fluid (SBF) to evaluate their potential application as vehicles for controlled releases. Furthermore, in vitro studies were performed to assess the cytotoxicity of matrices as compared to human lung fibroblast cells (MRC-5). The results revealed that the amount of MIBG incorporated within the studied matrices was indeed quite different, showing that only the hybrid [SBA-15/P(N-iPAAm)] system allowed for a more adequate release profile of MIGB. Taking all results into consideration, it can be concluded that the hybrid matrix [SBA-15/P(N-iPAAm)] can be considered a potential alternative material for the controlled release delivery of radio-pharmaceuticals.
Synthesis and Characterization of Poly(D,L-Lactide-co-Glycolide) Copolymer  [PDF]
Cynthia D’Avila Carvalho Erbetta, Ricardo José Alves, Jarbas Magalh?es Resende, Roberto Fernando de Souza Freitas, Ricardo Geraldo de Sousa
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2012, DOI: 10.4236/jbnb.2012.32027
Abstract: The copolymer poly(D,L-lactide-co-glycolide) is one of the most interesting polymers for medical applications. This interest is justified by the fact that it is bioreabsorbable, biocompatible and non-toxic, while its degradation kinetics can be modified by the copolymerization ratio of the monomers. In this study, copolymers were synthesised at 175?C by opening the rings of the cyclic dimers of the D,L-lactide and glycolide monomers in the presence of stannous octoate initiator and lauryl alcohol co-initiator. The application of vacuum to the reaction medium, coupled with adequate stirring, is essential for obtaining good results. The following analytical techniques were used to characterise the synthesised copolymers: Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Nuclear Magnetic Resonance Spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Both the input monomers and the reaction products were analysed. Important characteristics, such as melting temperature, glass transition temperature, thermal stability, chemical composition and the ratio of the monomers in the synthesised copolymer, were obtained from these analyses. These results helped to infer the absence of residual monomers in the synthesised copolymers.
Rheological and Thermal Behavior of High-Density Polyethylene (HDPE) at Different Temperatures  [PDF]
Cynthia D’Avila Carvalho Erbetta, Getúlio F. Manoel, Ana Paula Lelis Rodrigues Oliveira, Maria Elisa Scarpelli Ribeiro e Silva, Roberto Fernando Souza Freitas, Ricardo Geraldo Sousa
Materials Sciences and Applications (MSA) , 2014, DOI: 10.4236/msa.2014.513094
Abstract: In the present work, rheological properties of HDPE samples were measured at temperatures of 150°C, 190°C and 230°C. It was shown, by oscillatory tests, at low frequencies, that, for temperatures of 150°C and 190°C, there was a predominance of the viscous behavior over the elastic one. At 230°C, there was a predominance of the elastic contribution, and there was an increase of the molar mass compared with the ones obtained from the tests at 150°C and 190°C. The results obtained from the temperature ramp oscillatory test showed that, up to around 248°C, the viscous behavior prevailed, the opposite being observed at higher temperatures. At 230°C the sample showed significantly lower values of strain when compared with the ones observed at 150°C and 190°C. Oxidative induction time (OIT), melting point and degree of crystallinity were determined by differential scanning calorimetry (DSC). The DSC results and the rheological measurements showed a completely different behavior for the HDPE samples at 230°C compared with the 150°C and the 190°C ones, suggesting that HDPE, at the temperature of 230°C, underwent thermo-oxidative degradation with the initial predominance of crosslinking.
Synthesis, Characterization, and Study of PLGA Copolymer in Vitro Degradation  [PDF]
Anamaria Teodora Coêlho Rios Silva, Barbara Camilla Oliveira Cardoso, Maria Elisa Scarpelli Ribeiro e Silva, Roberto Fernando Souza Freitas, Ricardo Geraldo Sousa
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2015, DOI: 10.4236/jbnb.2015.61002
Abstract: The poly(lactic-co-glycolic acid), known as PLGA, is one of the main bioreabsorbable polymers used in the field of medicine today. This copolymer is widely applied in sutures, devices geared toward the controlled release of medication, and the guided regeneration of bone tissue as it presents a short degradation time. This work aimed to synthesize the 82/18 PLGA (expressed by the mass ratio of D,L-lactide and glycolide, respectively), to characterize and study the in Vitro degradation in the form of rods in phosphate buffer solution (PBS). The copolymer was synthesized by opening the cyclic dimer rings of the monomers D,L-lactide and glycolide, in the presence of the tin octanoate initiator and of the lauryl alcohol co-initiator. The characterization of the copolymer and the follow-up of its in vitro degradation were studied using: Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Infrared Molecular Absorption Spectroscopy with Fourier Transform (FTIR), Rheometry, and Scanning Electron Microscopy (SEM). Through these characterization techniques, it was possible to obtain the glass transition temperature, thermal stability, chemical composition, morphology, and molar mass of both the synthesized and the degraded copolymer. The molar mass of the synthesized copolymer was, approximately, 106 g·mol-1. The degradation rate of PLGA significantly increased from the 19th to the 28th day in PBS. After 28 days in PBS, the glass transition temperature and the molar mass reduced from 45°C to 17°C and from 1.5 × 106 g·mol-1 to 7.5 × 10g·mol
Coccidioidomicose pulmonar em ca ador de tatus
Jornal de Pneumologia , 2001,
Abstract: A coccidioidomicose, uma doen a fúngica adquirida através da inala o do agente Coccidioides immitis sob forma de artroconídio, vem sendo descrita desde 1892. Restringe-se principalmente a áreas de clima árido, solo alcalino e regi es de baixo índice pluviométrico. N o por acaso, a maioria dos casos descritos no Brasil ocorreu na regi o Nordeste. Relata-se o caso de um homem de 19 anos, imunocompetente, com queixa de dor pleural bilateral, febre, adinamia e tosse seca havia dois meses. A radiografia de tórax evidenciou múltiplos nódulos bilaterais. O paciente participava de ca adas a tatus (Dasypus novemcinctus) e a pesquisa direta para fungos no escarro evidenciou Coccidioides sp. Tratado com anfotericina B, apresentou pneumotórax e insuficiência respiratória, indo a óbito. A biópsia pulmonar post mortem evidenciou Coccidioides immitis sob a forma de endósporos.
Rheological Study of Polymers Used as Viscosity Index Improvers for Automotive Lubricant Oils  [PDF]
Ana Paula Pena Almeida, Ana Paula Lelis Rodrigues de Oliveira, Cynthia D’ávila Carvalho Erbetta, Ricardo Geraldo de Sousa, Roberto Fernando de Souza Freitas, Maria Elisa Scarpelli Ribeiro e Silva
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.512110

In this work, a rheological study of automotive lubricant oils, neutral light paraffinic (NLP) and neutral medium paraffinic (NMP), additivated with two commercial viscosity index improvers-VIIs, based on hydrogenated poly (isoprene-co-styrene), at different concentrations, was carried out. The study included the determination of the kinematic viscosity of the mixtures, the calculation of the viscosity indexes and their behavior when subjected to various rheometric experiments, including stress sweep, steady state flow, creep and recovery, and temperature ramp oscillatory tests. The obtained results showed the efficacy of the additives as viscosity index improvers, enabling a significant increase in the viscosity index of the pure oils at relatively low concentrations. The determination of the storage (G’) and of the loss (G”) moduli for the mixtures oil/VII additives showed a large predominance of the viscous effect over the elastic one. Except when under low shear stress, the mixtures showed a pseudoplastic behavior, with the flow curves being adjusted to fit the Ostwald-de-Waele model (Power Law), with negative flow behavior indexes.

Anatomy and Variations of the Celiac Trunk
Petrella,Selma; Rodriguez,Celio Fernando de Sousa; Sgrott,Emerson Alexandre; Fernandes,Geraldo José Medeiros; Marques,Sergio Ricardo; Prates,José Carlos;
International Journal of Morphology , 2007, DOI: 10.4067/S0717-95022007000200002
Abstract: the aim of this study was to analyze anatomy of the celiac trunk through its diameter, length, emission and variation of its branches. sixty-nine cadavers fixed in 10% formalin solution were dissected in the anatomy laboratories of the federal university of sao paulo (unifesp/epm), lusiadas of santos university (unilus) and santo amaro university (unisa) and 20 non-fixed cadavers from death verification services, of the sao paulo university (usp) and federal university of sao paulo (unifesp/epm). dissection of the trunk celiac of these cadavers was performed after opening of the peritoneal cavity. the obtained results allowed us to conclude the following: 1) mensuration of the length from the celiac trunk up to its first branch, the left gastric and/or splenic artery in 81 cadavers with a mean length of 1.23 cm in males, and 1.18 cm in females. we verified as the first branch of the celiac trunk, the left gastric artery in 55 ( 67.90%), splenic artery in two (2.47%), both in six (7.41%), and in 18 (22.22%) the three arteries trifiircating at the same level, forming the haller's tripod. 2) mensuration of the length from the celiac trunk up to its last artery, the common hepatic and/or splenic artery in 68 cadavers, with a mean length of 1.74 cm in males, 1.74 cm in females. we verified as the last branch of the celiac trunk, the common hepatic artery in 13 (19.12%), the splenic in four (5.88%), both in 33 (48.53%) and 18 (22.22%) the three arteries trifiircating at the same level. 3) mensuration of the celiac trunk diameter in 77 cadavers had a mean of 0.65 cm in males and 0.67 cm females. 4) mensuration of the distance between the celiac trunk and superior mesenteric artery in 76 cadavers had a mean of 0.72 cm in males and 0.74 cm in females. 5) the celiac trunk emitted in 73 (82.02%) out of the 89 cadavers the left gastric, splenic and hepatic arteries. in the remaining 16(17.98%) variations regarding the number of emitted arteries and their disposition in the celi
Origin of Inferior Phrenic Arteries in the Celiac Trunk
Petrella,Selma; Rodriguez,Celio Fernando de Sousa; Sgrott,Emerson Alexandre; Medeiros Fernandes,Geraldo José; Marques,Sergio Ricardo; Prates,José Carlos;
International Journal of Morphology , 2006, DOI: 10.4067/S0717-95022006000300024
Abstract: the knowledge of the arterial anatomic variations is very important for the clinical, radiological and surgical diagnosis. regarding inferior phrenic arteries, which irrigate the diaphragm, it is known that they vary in relation to their origin. the purpose of the present study is to verify these variations. the abdominal cavity of eighty-nine adult cadavers of both sexes was dissected, of which 69 fixed in 10% formalin solution and 20 non-fixed. the fixed cadavers were dissected in laboratories of anatomy of the federal university of s?o paulo (unifesp-epm), the santo amaro university (unisa) and lusiadas de santos university (unilus). the non-fixed cadavers were dissected from the death verification service of the city of s?o paulo (usp) and from the unifesp brazil. after exposure of the celiac axis, we analyzed the possible emission of inferior phrenic arteries from this vessel as well as site of origin. the results showed us the presence of inferior phrenic arteries in 31 (34.83%) among the 89 cadavers. in the remained 58 (65.17%), the celiac trunkhad not these branches. it was observed that in 19 (21.35%) out of the 89 cadavers the inferior phrenic artery originating at the left contour of the celiac axis, in five (5.62%) cadavers, the phrenic artery presented its origin at the right contour and seven (7.86%) presented two phrenic arteries of which five were independently originated from each side of the celiac trunk and two (2.25%) from one axis
Relationship of the Celiac Trunk with Median Arcuate Ligament of the Diaphragm
Petrella,Selma; Rodriguez,Celio Fernando de Sousa; Sgrott,Emerson Alexandre; Fernandes,Geraldo José Medeiros; Marques,Sergio Ricardo; Prates,José Carlos;
International Journal of Morphology , 2006, DOI: 10.4067/S0717-95022006000300023
Abstract: in the present study different positions of the median arcuate ligament in relation to the celiac trunk as well as measurements of overlap and distance, also the approach between the two structures were investigated. in addition histological studies of the diaphragm crura and the median arcuate ligament were performed. sixty-three cadavers fixed in formalin 10% aqueous solution and 20 non-fixed adult cadavers of both sexes were studied. dissections of the celiac trunk were performed after dissection of the peritoneal cavity in the laboratories of the anatomy division of the unifesp-epm, unilus and unisa, and during necropsies in the city morgue of the unifesp-epm and usp. regarding morphological analysis under light microscopy, three non-fixed cadavers were randomly chose and fragments measuring 5 cm height versus 2,5cm length of the median arcuate ligament were removed and processed according to routine techniques of inclusion. sections of 5 μm were hematoxyline-eosin stained according to masson's technique. the results allowed us to conclude the following: 1) the positions of the median arcuate ligament in the celiac trunk were analyzed irrespective of the gender. in 12 (14.46%) out of the 83 cadavers, the celiac trunk was distant from the median arcuate ligament. in 35 (42.17%) cadavers this ligament touched the celiac trunk and in 36 (43.37%) overlaps this vessel. the mean distance between the median arcuate ligament and the celiac trunk was 0.94 cm and the overlap was 0.42cm; 2) the histological analysis of the median arcuate ligament showed a dense connective tissue infiltrated by adipose cells, blood vessels and nerves. striated skeletal muscle fibers intermingled with collagenous fibers was observed in continuity to the tissues above mentioned
Coccidioidomicose pulmonar em ca?ador de tatus
Jornal de Pneumologia , 2001, DOI: 10.1590/S0102-35862001000500009
Abstract: coccidioidomycosis is a disease caused by inhalation of arthrospores of the fungus coccidioides immitis. it has been recognized as a clinical entity since 1892. it is related to activities that involves dust exposure. it is found in many regions of the western hemisphere with dry and alkaline soil. in brazil it has been described almost exclusively in the northeast region where drought periods may favor its growth in its soil. we report a case of fatal coccidioidomycosis, in an immunocompetent host, associated to the activity of armadillo hunting (dasypus novemcynctus) in a rural area of ceará state.
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