IEEE John Vincent Atanasoff 2006 International Symposium on Modern Computing (JVA'06), 2006
Page 1. HPC-ICTM: a Parallel Model for Geographic Categorization Rafael K. Santos Silva and César... more Page 1. HPC-ICTM: a Parallel Model for Geographic Categorization Rafael K. Santos Silva and César AF De Rose PPGCC, Catholic University of Rio Grande do Sul (PUCRS) Av. Ipiranga 6681, 906190-9000 Porto Alegre, Brazil [email protected], [email protected] ...
Abstract: This research aimed at determining the pediatric patients profile at a School-Hospital,... more Abstract: This research aimed at determining the pediatric patients profile at a School-Hospital, according to the variables sex, age, patients lenght-of stay, colonizing/infecting microorganisms, nosocomial infections (NI) and patiens outcomes. This was a prospective ...
ABCD. Arquivos Brasileiros de Cirurgia Digestiva (São Paulo), 2015
Large number of surgical services use laparoscopy to approach the colon. One of the concerns on t... more Large number of surgical services use laparoscopy to approach the colon. One of the concerns on the resection using this way is the high rate of cancer relapse at in- and outlet site of the surgical instruments. To describe a protective device for surgical isolation in laparoscopic colectomy. The device is made of sterile polyethylene plastic cover used to protect the fiber optic cable in laparoscopic surgery and one 20 Fr. urethral catheter working as a conduit. The device was used in six laparoscopic colectomies, three for adenocarcinoma of the colon and three for intestinal endometriosis. It was effective to avoid contact of the specimen with the abdominal wall, in order to reduce the risk of implantation of cancer or endometriotic cells and surgical site infection. The device was made intraoperative at all surgeries and allowed good visualization in laparoscopy and maintenance of the pneumoperitoneum. It cost R$ 22,00 (approximately US$ 10), R$14.50 related to the plastic cover and R$7.50, the urethral tube. The production time of the device and its installation in the abdominal cavity was measured in each procedure and was, on average, respectively, of 66 s and 25 s. The device proved to be feasible, not requiring any special training and can be performed by the surgical team itself, even at institutions with limited resources.
Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolysis of the N-ribosidic bonds of pu... more Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolysis of the N-ribosidic bonds of purine nucleosides and deoxynucleosides. A genetic deficiency due to mutations in the gene encoding for human PNP causes T-cell deficiency as the major physiological defect. Inappropriate activation of T-cells has been implicated in several clinically relevant human conditions such as transplant tissue rejection, psoriasis, rheumatoid arthritis, lupus, and T-cell lymphomas. Human PNP is therefore a target for inhibitor development aiming at T-cell immune response modulation. In addition, bacterial PNP has been used as reactant in a fast and sensitive spectrophotometric method that allows both quantitation of inorganic phosphate (P(i)) and continuous assay of reactions that generate P(i) such as those catalyzed by ATPases and GTPases. Human PNP may therefore be an important biotechnological tool for P(i) detection. However, low expression of human PNP in bacterial hosts, protein purificatio...
Beta-ketoacyl-ACP reductase catalyzes the NADPH-dependent reduction of beta-ketoacyl-acyl carrier... more Beta-ketoacyl-ACP reductase catalyzes the NADPH-dependent reduction of beta-ketoacyl-acyl carrier protein to generate beta-hydroxyacyl-acyl carrier protein and NADP+, the second step of the fatty acid elongation system type II of bacteria, plants, and apicomplexan organisms. Here, a modified and more efficient purification protocol is reported for recombinant Mycobacterium tuberculosis beta-ketoacyl-ACP reductase (MabA). The increase in alpha-secondary deuterium kinetic isotope effect values measured at pH 10 as compared to those obtained at pH 7 points to isotope- and pH-sensitive steps occurring concomitantly. Equilibrium and kinetic fluorescence studies demonstrate positive cooperativity in binding of NADPH to MabA, with two forms of free enzyme in solution. Equilibrium dialysis shows no cooperativity in acetoacetyl-CoA binding to the enzyme. Moreover, modest affinity loss occurs when the substrates bind to the monomer as compared to the dimer of MabA. A mechanism of substrate bi...
Recebido em 19/1/09; aceito em 25/3/09; publicado na web em 2/4/09 APPLICATIONS OF LIGNOCELLULOSI... more Recebido em 19/1/09; aceito em 25/3/09; publicado na web em 2/4/09 APPLICATIONS OF LIGNOCELLULOSIC FIBERS IN POLYMER CHEMISTRY AND IN COMPOSITES. The use of lignocellulosic fibers and their constituents, as raw materials in the production of polymeric and composite materials, represent an exceptional opportunity of sustainable technological development. In the present report works that discuss promising alternatives of obtaining and use of materials such as cellulose, hemicellulose, lignin, cellulose nanocrystals and biocomposites were revised. The advance in the use of biomass can be, in a near future, capable of going beyond the application difficulties of these vast materials, especially in relation to the economical unviability, by the production of high performance polymeric and composite materials. This advance would represent a higher profitability to some areas of agrobusiness, especially the sector of biofuels, which produces elevated amounts of biomass waste.
Revista Brasileira de Hematologia e Hemoterapia, 2007
O mieloma múltiplo (MM) é uma doença maligna de células plasmáticas incurável. O transplante de c... more O mieloma múltiplo (MM) é uma doença maligna de células plasmáticas incurável. O transplante de células-tronco hematopoéticas (TCTH) faz parte da estratégia terapêu-tica para a maioria dos pacientes. Devido à distribuição heterogênea dos centros de transplante no nosso país, os autores têm por objetivo descrever a experiência de um centro nordestino no tratamento desta entidade. De fevereiro de 2000 a dezembro de 2005 foram realizados e analisados de maneira prospectiva 21 TCTH autólogos para pacientes com MM no Hospital Português da Bahia. Epidemiologicamente houve pre-domínio do sexo feminino (1,6:1) e uma predominância de caucasianos (61,9%). A mediana de idade ao diagnóstico foi de 58 anos, sendo a maioria secretores de IgG (71,4%) que se apresentavam com estágio clínico IIIA (90,5%). A indicação para o procedimento foi a consolidação da remissão (RC) obtida inicialmente pela quimioterapia (52,4%) ou o resgate de uma doença refratária (47,6%). A taxa de sobrevida global (SG) foi de 74,7%, a taxa de sobrevida livre de doença (SLD) foi de 61,9% e a taxa de mortalidade (TM) foi de 5% nos primeiros cem dias. Quando avaliamos os pacientes transplantados em relação à fase da doença no momento do procedimento, observamos que aqueles transplantados em RC tiveram SG e SLD superiores àqueles não transplantados em RC (90,9% vs 64% e 68,2% vs 56%). Embora com uma epidemiologia peculiar, os resultados se mostraram semelhantes aos da literatura mundial, reforçando o fato de que o TCTH autólogo é fundamental na estratégia terapêutica contra o MM e está disponível no nordeste brasileiro. Rev. bras. hematol. hemoter. 2007;29(2):144-148. Palavras-chave: Mieloma múltiplo; transplante de células-tronco hematopoéticas; tratamento. Introdução O mieloma múltiplo (MM) é uma doença maligna peculiar que envolve não só as células plasmáticas que proliferam de forma clonal, mas também o microambiente medular. Epidemiologicamente, esta doença que acomete pacientes próximos da sexta década de vida é responsável por 1% de todos os tipos de câncer e por 10% das neoplasias hema-tológicas. Sua incidência é de aproximadamente 14 mil casos ao ano, sendo mais freqüente em negros do que em brancos,
We present here comparative assessments of murine lung toxicity (biocompatibility) after in vitro... more We present here comparative assessments of murine lung toxicity (biocompatibility) after in vitro and in vivo exposures to carbon (C-SiO 2 -etched), carbon-silica (C-SiO 2 ), carbon-cobalt-silica (C-Co-SiO 2 ), and carbon-cobalt oxide-silica (C-Co 3 O 4 -SiO 2 ) nanoparticles. These nanoparticles have potential applications in clinical medicine and bioimaging, and thus their possible adverse events require thorough investigation. The primary aim of this work was to explore whether the nanoparticles are biocompatible with pneumatocyte bioenergetics (cellular respiration and adenosine triphosphate content). Other objectives included assessments of caspase activity, lung structure, and cellular organelles. Pneumatocyte bioenergetics of murine lung remained preserved after treatment with C-SiO 2 -etched or C-SiO 2 nanoparticles. C-SiO 2etched nanoparticles, however, increased caspase activity and altered lung structure more than C-SiO 2 did. Consistent with the known mitochondrial toxicity of cobalt, both C-Co-SiO 2 and C-Co 3 O 4 -SiO 2 impaired lung tissue bioenergetics. C-Co-SiO 2 , however, increased caspase activity and altered lung structure more than C-Co 3 O 4 -SiO 2 . The results indicate that silica shell is essential for biocompatibility. Furthermore, cobalt oxide is the preferred phase over the zerovalent Co(0) phase to impart biocompatibility to cobalt-based nanoparticles.
In this study, conventional restorative glass ionomer cement (GIC) was modified by embedding it w... more In this study, conventional restorative glass ionomer cement (GIC) was modified by embedding it with mechanically processed cellulose fibers. Two concentrations of fibers were weighed and agglutinated into the GIC during manipulation, yielding Experimental Groups 2 (G2; 3.62 wt% of fibers) and 3 (G3; 7.24 wt% of fibers), which were compared against a control group containing no fibers (G1). The compressive strengths and elastic modulus of the three groups, and their diametral tensile strengths and stiffness, were evaluated on a universal test machine. The compressive and diametral tensile strengths were significantly higher in G3 than in G1. Statistically significant differences in elastic modulus were also found between G2 and G1 and between G2 and G3, whereas the stiffness significantly differed between G1 and G2. The materials were then characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Heterogeneously shaped particles were found o...
LASSBio-1135 is an imidazo[1,2-a]pyridine derivative with high efficacy in screening models of no... more LASSBio-1135 is an imidazo[1,2-a]pyridine derivative with high efficacy in screening models of nociception and inflammation, presumed as a weak COX-2 inhibitor. In order to tease out its mechanism of action, we investigated others possible target for LASSBio-1135, such as TNF-α and TRPV1, to better characterize it as a multitarget compound useful in the treatment of chronic pain. TRPV1 modulation was assessed in TRPV1-expressing Xenopus oocytes against capsaicin and low pH-induced current. Modulation of TNF-α production was evaluated in culture of macrophages stimulated with LPS. In vivo efficacy of LASSBio-1135 was investigated in carrageenan and partial sciatic ligation-induced thermal hyperalgesia and mechanical allodynia. Corroborating its previous demonstration of efficacy in a model of capsaicin-induced hyperalgesia, LASSBio-1135 blocks capsaicin-elicited currents in a non-competitive way with an IC50 of 580 nM as well as low pH-induced current at 50 µM. As an additional actio...
IFIP International Federation for Information Processing, 2006
The number of software defects found in software applications today costs users and companies bil... more The number of software defects found in software applications today costs users and companies billions of dollars annually. In general, these defects occur due to an inadequate software development process that does not give the necessary importance to testing. Another contributor to these costs is the lack of adequate automated tools that can find “bugs” that would not otherwise be verified by experts. This paper looks at the combinatorial characteristics of the problem of testing—tools essentially search among all test cases for ...
Proceedings of the 2007 ACM symposium on Applied computing - SAC '07, 2007
When looking at science and technology today, we find a recurrent problem to many fields: how to ... more When looking at science and technology today, we find a recurrent problem to many fields: how to cover a search space consistently and uniformly. This problem is encountered in robotics (searching for targets), optimization (searching for solutions), mathematics and computer science (graph traversals), and even in software engineering (the main motivation for this research). In insect societies, and in particular ant colonies, one can find the concept of alarm pheromones used to indicate an important event to the society (e.g. a threat). Alarm pheromones enable the society to have a uniform spread of its individuals, probably as a survival mechanism -the more uniform the spread the better the changes of survival at the colony level. This paper proposes a model of this ant behavior which can be used to solve the aforementioned problem. The model, called ALARM is inspired primarily by ACO and from observations of ants alarm behavior. We compare the model with a random walk, to demonstrate a significant improvement over this approach.
Proceedings of the 44th annual southeast regional conference on - ACM-SE 44, 2006
Abstract Like in other fields, computer products (applications, hardware, etc.), before being mar... more Abstract Like in other fields, computer products (applications, hardware, etc.), before being marketed, require some level of testing to verify whether they meet their design and functional specifications--called functionality test. The general process of performing functionality test consists in the production of a test plan that is then executed by humans or by automated software tools. The main difficulty in this entire process is the definition of such test plan. How can we know what a good sequence (test plan) is? The rule of thumb is to ...
Tuberculosis (TB) poses a major worldwide public health problem. The increasing prevalence of TB,... more Tuberculosis (TB) poses a major worldwide public health problem. The increasing prevalence of TB, the emergence of multi-drugresistant strains of Mycobacterium tuberculosis, the causative agent of TB, and the devastating effect of co-infection with HIV have highlighted the urgent need for the development of new antimycobacterial agents. Analysis of the complete genome sequence of M. tuberculosis shows the presence of genes involved in the aromatic amino acid biosynthetic pathway. Experimental evidence that this pathway is essential for M. tuberculosis has been reported. The genes and pathways that are essential for the growth of the microorganisms make them attractive drug targets since inhibiting their function may kill the bacilli. We have previously cloned and expressed in the soluble form the fourth shikimate pathway enzyme of the M. tuberculosis, the aroE-encoded shikimate dehydrogenase (mtSD). Here, we present the purification of active recombinant aroE-encoded M. tuberculosis shikimate dehydrogenase (mtSD) to homogeneity, N-terminal sequencing, mass spectrometry, assessment of the oligomeric state by gel filtration chromatography, determination of apparent steady-state kinetic parameters for both the forward and reverse directions, apparent equilibrium constant, thermal stability, and energy of activation for the enzyme-catalyzed chemical reaction. These results pave the way for structural and kinetic studies, which should aid in the rational design of mtSD inhibitors to be tested as antimycobacterial agents.
Proceedings of the National Academy of Sciences, 2011
Contributions of fast (femtosecond) dynamic motion to barrier crossing at enzyme catalytic sites ... more Contributions of fast (femtosecond) dynamic motion to barrier crossing at enzyme catalytic sites is in dispute. Human purine nucleoside phosphorylase (PNP) forms a ribocation-like transition state in the phosphorolysis of purine nucleosides and fast protein motions have been proposed to participate in barrier crossing. In the present study, 13 C−, 15 N−, 2 H−labeled human PNP (heavy PNP) was expressed, purified to homogeneity, and shown to exhibit a 9.9% increase in molecular mass relative to its unlabeled counterpart (light PNP). Kinetic isotope effects and steady-state kinetic parameters were indistinguishable for both enzymes, indicating that transition-state structure, equilibrium binding steps, and the rate of product release were not affected by increased protein mass. Single-turnover rate constants were slowed for heavy PNP, demonstrating reduced probability of chemical barrier crossing from enzyme-bound substrates to enzyme-bound products. In a second, independent method to probe barrier crossing, heavy PNP exhibited decreased forward commitment factors, also revealing mass-dependent decreased probability for barrier crossing. Increased atomic mass in human PNP alters bond vibrational modes on the femtosecond time scale and reduces on-enzyme chemical barrier crossing. This study demonstrates coupling of enzymatic bond vibrations on the femtosecond time scale to barrier crossing. femtosecond motions | kinetic isotope effect | transition state structure | enzymatic catalysis | protein dynamics
A novel procedure has been developed to covalently graft multiple hydrophilic polymer ultra-thin ... more A novel procedure has been developed to covalently graft multiple hydrophilic polymer ultra-thin layers to functionalized polyethylene surface. Polyethylene films have been functionalized by two methods, chromic acid oxidation and maleic anhydride grafting, to produce ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2009
... energies (E) above 1500 keV for coaxial semiconductor were obtained for extrapolation and adj... more ... energies (E) above 1500 keV for coaxial semiconductor were obtained for extrapolation and adjusted by means of the potential curve: ε=aE −b which could be transformed to the general linear form (linear log–log extrapolation method discussed by Debertin and Helmer in Ref. ...
IEEE John Vincent Atanasoff 2006 International Symposium on Modern Computing (JVA'06), 2006
Page 1. HPC-ICTM: a Parallel Model for Geographic Categorization Rafael K. Santos Silva and César... more Page 1. HPC-ICTM: a Parallel Model for Geographic Categorization Rafael K. Santos Silva and César AF De Rose PPGCC, Catholic University of Rio Grande do Sul (PUCRS) Av. Ipiranga 6681, 906190-9000 Porto Alegre, Brazil [email protected], [email protected] ...
Abstract: This research aimed at determining the pediatric patients profile at a School-Hospital,... more Abstract: This research aimed at determining the pediatric patients profile at a School-Hospital, according to the variables sex, age, patients lenght-of stay, colonizing/infecting microorganisms, nosocomial infections (NI) and patiens outcomes. This was a prospective ...
ABCD. Arquivos Brasileiros de Cirurgia Digestiva (São Paulo), 2015
Large number of surgical services use laparoscopy to approach the colon. One of the concerns on t... more Large number of surgical services use laparoscopy to approach the colon. One of the concerns on the resection using this way is the high rate of cancer relapse at in- and outlet site of the surgical instruments. To describe a protective device for surgical isolation in laparoscopic colectomy. The device is made of sterile polyethylene plastic cover used to protect the fiber optic cable in laparoscopic surgery and one 20 Fr. urethral catheter working as a conduit. The device was used in six laparoscopic colectomies, three for adenocarcinoma of the colon and three for intestinal endometriosis. It was effective to avoid contact of the specimen with the abdominal wall, in order to reduce the risk of implantation of cancer or endometriotic cells and surgical site infection. The device was made intraoperative at all surgeries and allowed good visualization in laparoscopy and maintenance of the pneumoperitoneum. It cost R$ 22,00 (approximately US$ 10), R$14.50 related to the plastic cover and R$7.50, the urethral tube. The production time of the device and its installation in the abdominal cavity was measured in each procedure and was, on average, respectively, of 66 s and 25 s. The device proved to be feasible, not requiring any special training and can be performed by the surgical team itself, even at institutions with limited resources.
Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolysis of the N-ribosidic bonds of pu... more Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolysis of the N-ribosidic bonds of purine nucleosides and deoxynucleosides. A genetic deficiency due to mutations in the gene encoding for human PNP causes T-cell deficiency as the major physiological defect. Inappropriate activation of T-cells has been implicated in several clinically relevant human conditions such as transplant tissue rejection, psoriasis, rheumatoid arthritis, lupus, and T-cell lymphomas. Human PNP is therefore a target for inhibitor development aiming at T-cell immune response modulation. In addition, bacterial PNP has been used as reactant in a fast and sensitive spectrophotometric method that allows both quantitation of inorganic phosphate (P(i)) and continuous assay of reactions that generate P(i) such as those catalyzed by ATPases and GTPases. Human PNP may therefore be an important biotechnological tool for P(i) detection. However, low expression of human PNP in bacterial hosts, protein purificatio...
Beta-ketoacyl-ACP reductase catalyzes the NADPH-dependent reduction of beta-ketoacyl-acyl carrier... more Beta-ketoacyl-ACP reductase catalyzes the NADPH-dependent reduction of beta-ketoacyl-acyl carrier protein to generate beta-hydroxyacyl-acyl carrier protein and NADP+, the second step of the fatty acid elongation system type II of bacteria, plants, and apicomplexan organisms. Here, a modified and more efficient purification protocol is reported for recombinant Mycobacterium tuberculosis beta-ketoacyl-ACP reductase (MabA). The increase in alpha-secondary deuterium kinetic isotope effect values measured at pH 10 as compared to those obtained at pH 7 points to isotope- and pH-sensitive steps occurring concomitantly. Equilibrium and kinetic fluorescence studies demonstrate positive cooperativity in binding of NADPH to MabA, with two forms of free enzyme in solution. Equilibrium dialysis shows no cooperativity in acetoacetyl-CoA binding to the enzyme. Moreover, modest affinity loss occurs when the substrates bind to the monomer as compared to the dimer of MabA. A mechanism of substrate bi...
Recebido em 19/1/09; aceito em 25/3/09; publicado na web em 2/4/09 APPLICATIONS OF LIGNOCELLULOSI... more Recebido em 19/1/09; aceito em 25/3/09; publicado na web em 2/4/09 APPLICATIONS OF LIGNOCELLULOSIC FIBERS IN POLYMER CHEMISTRY AND IN COMPOSITES. The use of lignocellulosic fibers and their constituents, as raw materials in the production of polymeric and composite materials, represent an exceptional opportunity of sustainable technological development. In the present report works that discuss promising alternatives of obtaining and use of materials such as cellulose, hemicellulose, lignin, cellulose nanocrystals and biocomposites were revised. The advance in the use of biomass can be, in a near future, capable of going beyond the application difficulties of these vast materials, especially in relation to the economical unviability, by the production of high performance polymeric and composite materials. This advance would represent a higher profitability to some areas of agrobusiness, especially the sector of biofuels, which produces elevated amounts of biomass waste.
Revista Brasileira de Hematologia e Hemoterapia, 2007
O mieloma múltiplo (MM) é uma doença maligna de células plasmáticas incurável. O transplante de c... more O mieloma múltiplo (MM) é uma doença maligna de células plasmáticas incurável. O transplante de células-tronco hematopoéticas (TCTH) faz parte da estratégia terapêu-tica para a maioria dos pacientes. Devido à distribuição heterogênea dos centros de transplante no nosso país, os autores têm por objetivo descrever a experiência de um centro nordestino no tratamento desta entidade. De fevereiro de 2000 a dezembro de 2005 foram realizados e analisados de maneira prospectiva 21 TCTH autólogos para pacientes com MM no Hospital Português da Bahia. Epidemiologicamente houve pre-domínio do sexo feminino (1,6:1) e uma predominância de caucasianos (61,9%). A mediana de idade ao diagnóstico foi de 58 anos, sendo a maioria secretores de IgG (71,4%) que se apresentavam com estágio clínico IIIA (90,5%). A indicação para o procedimento foi a consolidação da remissão (RC) obtida inicialmente pela quimioterapia (52,4%) ou o resgate de uma doença refratária (47,6%). A taxa de sobrevida global (SG) foi de 74,7%, a taxa de sobrevida livre de doença (SLD) foi de 61,9% e a taxa de mortalidade (TM) foi de 5% nos primeiros cem dias. Quando avaliamos os pacientes transplantados em relação à fase da doença no momento do procedimento, observamos que aqueles transplantados em RC tiveram SG e SLD superiores àqueles não transplantados em RC (90,9% vs 64% e 68,2% vs 56%). Embora com uma epidemiologia peculiar, os resultados se mostraram semelhantes aos da literatura mundial, reforçando o fato de que o TCTH autólogo é fundamental na estratégia terapêutica contra o MM e está disponível no nordeste brasileiro. Rev. bras. hematol. hemoter. 2007;29(2):144-148. Palavras-chave: Mieloma múltiplo; transplante de células-tronco hematopoéticas; tratamento. Introdução O mieloma múltiplo (MM) é uma doença maligna peculiar que envolve não só as células plasmáticas que proliferam de forma clonal, mas também o microambiente medular. Epidemiologicamente, esta doença que acomete pacientes próximos da sexta década de vida é responsável por 1% de todos os tipos de câncer e por 10% das neoplasias hema-tológicas. Sua incidência é de aproximadamente 14 mil casos ao ano, sendo mais freqüente em negros do que em brancos,
We present here comparative assessments of murine lung toxicity (biocompatibility) after in vitro... more We present here comparative assessments of murine lung toxicity (biocompatibility) after in vitro and in vivo exposures to carbon (C-SiO 2 -etched), carbon-silica (C-SiO 2 ), carbon-cobalt-silica (C-Co-SiO 2 ), and carbon-cobalt oxide-silica (C-Co 3 O 4 -SiO 2 ) nanoparticles. These nanoparticles have potential applications in clinical medicine and bioimaging, and thus their possible adverse events require thorough investigation. The primary aim of this work was to explore whether the nanoparticles are biocompatible with pneumatocyte bioenergetics (cellular respiration and adenosine triphosphate content). Other objectives included assessments of caspase activity, lung structure, and cellular organelles. Pneumatocyte bioenergetics of murine lung remained preserved after treatment with C-SiO 2 -etched or C-SiO 2 nanoparticles. C-SiO 2etched nanoparticles, however, increased caspase activity and altered lung structure more than C-SiO 2 did. Consistent with the known mitochondrial toxicity of cobalt, both C-Co-SiO 2 and C-Co 3 O 4 -SiO 2 impaired lung tissue bioenergetics. C-Co-SiO 2 , however, increased caspase activity and altered lung structure more than C-Co 3 O 4 -SiO 2 . The results indicate that silica shell is essential for biocompatibility. Furthermore, cobalt oxide is the preferred phase over the zerovalent Co(0) phase to impart biocompatibility to cobalt-based nanoparticles.
In this study, conventional restorative glass ionomer cement (GIC) was modified by embedding it w... more In this study, conventional restorative glass ionomer cement (GIC) was modified by embedding it with mechanically processed cellulose fibers. Two concentrations of fibers were weighed and agglutinated into the GIC during manipulation, yielding Experimental Groups 2 (G2; 3.62 wt% of fibers) and 3 (G3; 7.24 wt% of fibers), which were compared against a control group containing no fibers (G1). The compressive strengths and elastic modulus of the three groups, and their diametral tensile strengths and stiffness, were evaluated on a universal test machine. The compressive and diametral tensile strengths were significantly higher in G3 than in G1. Statistically significant differences in elastic modulus were also found between G2 and G1 and between G2 and G3, whereas the stiffness significantly differed between G1 and G2. The materials were then characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Heterogeneously shaped particles were found o...
LASSBio-1135 is an imidazo[1,2-a]pyridine derivative with high efficacy in screening models of no... more LASSBio-1135 is an imidazo[1,2-a]pyridine derivative with high efficacy in screening models of nociception and inflammation, presumed as a weak COX-2 inhibitor. In order to tease out its mechanism of action, we investigated others possible target for LASSBio-1135, such as TNF-α and TRPV1, to better characterize it as a multitarget compound useful in the treatment of chronic pain. TRPV1 modulation was assessed in TRPV1-expressing Xenopus oocytes against capsaicin and low pH-induced current. Modulation of TNF-α production was evaluated in culture of macrophages stimulated with LPS. In vivo efficacy of LASSBio-1135 was investigated in carrageenan and partial sciatic ligation-induced thermal hyperalgesia and mechanical allodynia. Corroborating its previous demonstration of efficacy in a model of capsaicin-induced hyperalgesia, LASSBio-1135 blocks capsaicin-elicited currents in a non-competitive way with an IC50 of 580 nM as well as low pH-induced current at 50 µM. As an additional actio...
IFIP International Federation for Information Processing, 2006
The number of software defects found in software applications today costs users and companies bil... more The number of software defects found in software applications today costs users and companies billions of dollars annually. In general, these defects occur due to an inadequate software development process that does not give the necessary importance to testing. Another contributor to these costs is the lack of adequate automated tools that can find “bugs” that would not otherwise be verified by experts. This paper looks at the combinatorial characteristics of the problem of testing—tools essentially search among all test cases for ...
Proceedings of the 2007 ACM symposium on Applied computing - SAC '07, 2007
When looking at science and technology today, we find a recurrent problem to many fields: how to ... more When looking at science and technology today, we find a recurrent problem to many fields: how to cover a search space consistently and uniformly. This problem is encountered in robotics (searching for targets), optimization (searching for solutions), mathematics and computer science (graph traversals), and even in software engineering (the main motivation for this research). In insect societies, and in particular ant colonies, one can find the concept of alarm pheromones used to indicate an important event to the society (e.g. a threat). Alarm pheromones enable the society to have a uniform spread of its individuals, probably as a survival mechanism -the more uniform the spread the better the changes of survival at the colony level. This paper proposes a model of this ant behavior which can be used to solve the aforementioned problem. The model, called ALARM is inspired primarily by ACO and from observations of ants alarm behavior. We compare the model with a random walk, to demonstrate a significant improvement over this approach.
Proceedings of the 44th annual southeast regional conference on - ACM-SE 44, 2006
Abstract Like in other fields, computer products (applications, hardware, etc.), before being mar... more Abstract Like in other fields, computer products (applications, hardware, etc.), before being marketed, require some level of testing to verify whether they meet their design and functional specifications--called functionality test. The general process of performing functionality test consists in the production of a test plan that is then executed by humans or by automated software tools. The main difficulty in this entire process is the definition of such test plan. How can we know what a good sequence (test plan) is? The rule of thumb is to ...
Tuberculosis (TB) poses a major worldwide public health problem. The increasing prevalence of TB,... more Tuberculosis (TB) poses a major worldwide public health problem. The increasing prevalence of TB, the emergence of multi-drugresistant strains of Mycobacterium tuberculosis, the causative agent of TB, and the devastating effect of co-infection with HIV have highlighted the urgent need for the development of new antimycobacterial agents. Analysis of the complete genome sequence of M. tuberculosis shows the presence of genes involved in the aromatic amino acid biosynthetic pathway. Experimental evidence that this pathway is essential for M. tuberculosis has been reported. The genes and pathways that are essential for the growth of the microorganisms make them attractive drug targets since inhibiting their function may kill the bacilli. We have previously cloned and expressed in the soluble form the fourth shikimate pathway enzyme of the M. tuberculosis, the aroE-encoded shikimate dehydrogenase (mtSD). Here, we present the purification of active recombinant aroE-encoded M. tuberculosis shikimate dehydrogenase (mtSD) to homogeneity, N-terminal sequencing, mass spectrometry, assessment of the oligomeric state by gel filtration chromatography, determination of apparent steady-state kinetic parameters for both the forward and reverse directions, apparent equilibrium constant, thermal stability, and energy of activation for the enzyme-catalyzed chemical reaction. These results pave the way for structural and kinetic studies, which should aid in the rational design of mtSD inhibitors to be tested as antimycobacterial agents.
Proceedings of the National Academy of Sciences, 2011
Contributions of fast (femtosecond) dynamic motion to barrier crossing at enzyme catalytic sites ... more Contributions of fast (femtosecond) dynamic motion to barrier crossing at enzyme catalytic sites is in dispute. Human purine nucleoside phosphorylase (PNP) forms a ribocation-like transition state in the phosphorolysis of purine nucleosides and fast protein motions have been proposed to participate in barrier crossing. In the present study, 13 C−, 15 N−, 2 H−labeled human PNP (heavy PNP) was expressed, purified to homogeneity, and shown to exhibit a 9.9% increase in molecular mass relative to its unlabeled counterpart (light PNP). Kinetic isotope effects and steady-state kinetic parameters were indistinguishable for both enzymes, indicating that transition-state structure, equilibrium binding steps, and the rate of product release were not affected by increased protein mass. Single-turnover rate constants were slowed for heavy PNP, demonstrating reduced probability of chemical barrier crossing from enzyme-bound substrates to enzyme-bound products. In a second, independent method to probe barrier crossing, heavy PNP exhibited decreased forward commitment factors, also revealing mass-dependent decreased probability for barrier crossing. Increased atomic mass in human PNP alters bond vibrational modes on the femtosecond time scale and reduces on-enzyme chemical barrier crossing. This study demonstrates coupling of enzymatic bond vibrations on the femtosecond time scale to barrier crossing. femtosecond motions | kinetic isotope effect | transition state structure | enzymatic catalysis | protein dynamics
A novel procedure has been developed to covalently graft multiple hydrophilic polymer ultra-thin ... more A novel procedure has been developed to covalently graft multiple hydrophilic polymer ultra-thin layers to functionalized polyethylene surface. Polyethylene films have been functionalized by two methods, chromic acid oxidation and maleic anhydride grafting, to produce ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2009
... energies (E) above 1500 keV for coaxial semiconductor were obtained for extrapolation and adj... more ... energies (E) above 1500 keV for coaxial semiconductor were obtained for extrapolation and adjusted by means of the potential curve: ε=aE −b which could be transformed to the general linear form (linear log–log extrapolation method discussed by Debertin and Helmer in Ref. ...
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Papers by Rafael Silva