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Search Results: 1 - 10 of 416488 matches for " Pedro M Matos "
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HIV-1 Fusion Inhibitor Peptides Enfuvirtide and T-1249 Interact with Erythrocyte and Lymphocyte Membranes
Pedro M. Matos,Miguel A. R. B. Castanho,Nuno C. Santos
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0009830
Abstract: Enfuvirtide and T-1249 are two HIV-1 fusion inhibitor peptides that bind to gp41 and prevent its fusogenic conformation, inhibiting viral entry into host cells. Previous studies established the relative preferences of these peptides for membrane model systems of defined lipid compositions. We aimed to understand the interaction of these peptides with the membranes of erythrocytes and peripheral blood mononuclear cells. The peptide behavior toward cell membranes was followed by di-8-ANEPPS fluorescence, a lipophilic probe sensitive to the changes in membrane dipole potential. We observed a fusion inhibitor concentration-dependent decrease on the membrane dipole potential. Quantitative analysis showed that T-1249 has an approximately eight-fold higher affinity towards cells, when compared with enfuvirtide. We also compared the binding towards di-8-ANEPPS labeled lipid vesicles that model cell membranes and obtained concordant results. We demonstrated the distinct enfuvirtide and T-1249 membranotropism for circulating blood cells, which can be translated to a feasible in vivo scenario. The enhanced interaction of T-1249 with cell membranes correlates with its higher efficacy, as it can increase and accelerate the drug binding to gp41 in its pre-fusion state.
Optimización de la Concentración de L-Cisteína para la producción de 1,3-Propanodiol por una vía Biotecnológica
Ferreira,Tatiana F; Ribeiro,Roberta dos R; Matos,Pedro M; Coelho,Maria Alice Z;
Información tecnológica , 2013, DOI: 10.4067/S0718-07642013000100006
Abstract: glycerol was converted into 1,3-propanediol (1,3-pdo) using citrobacter freundii atcc 8090. 1,3-pdo is a bifunctional molecule that can be used in many applications, being of great commercial interest. the most recent route used for the production of this compound is through biotechnology using some micro-organisms capable of anaerobically converting glycerol into 1,3-pdo. the conversion done makes it necessary the addition of cysteine ??to the culture medium. five experiments were performed with cysteine at five concentrations to verify which is the optimum concentration that does not affect conversion of glycerol into 1,3-pdo. the concentrations used were 0.05, 0.10, 0.15, 0.20 and 0.25 gl-1. the yields were 15, 20, 26, 35 and 28 % respectively. according to the results it is concluded that the optimum cysteine concentration ??for 1,3-pdo production is 0.20 g.l-1.
Optimización de la Concentración de L-Cisteína para la producción de 1,3-Propanodiol por una vía Biotecnológica Optimization of L-Cysteine Concentration to produce 1,3-Propanediol by a Biotechnological route
Tatiana F Ferreira,Roberta dos R Ribeiro,Pedro M Matos,Maria Alice Z Coelho
Información Tecnológica , 2013,
Abstract: Se ha realizado la conversión de glicerol en 1,3-propanodiol (1,3-PDO) usando la cepa Citrobacter freundii ATCC 8090. El 1,3-PDO es una molécula bifuncional que puede ser utilizada para muchas aplicaciones, siendo así de gran interés comercial. Una ruta más reciente para la producción de este compuesto es la vía biotecnológica utilizando algunos microorganismos capaces de convertir anaeróbicamente glicerol en 1,3-PDO. La conversión realizada hace necesaria la adición de cisteína al medio de cultivo. Se realizaron cinco experimentos con cinco concentraciones de cisteína con el fin de verificar cuál es la menor concentración posible que no afecta la conversión de glicerol en 1,3-PDO. Las concentraciones utilizadas fueron 0,05; 0,10; 0,15; 0,20 y 0,25 g.L-1. Los rendimientos fueron 15, 20, 26, 35 y 28 % respectivamente. De acuerdo a los resultados se concluye que la concentración óptima de cisteína para la producción de 1,3-PDO es 0,20 g.L-1. Glycerol was converted into 1,3-propanediol (1,3-PDO) using Citrobacter freundii ATCC 8090. 1,3-PDO is a bifunctional molecule that can be used in many applications, being of great commercial interest. The most recent route used for the production of this compound is through biotechnology using some micro-organisms capable of anaerobically converting glycerol into 1,3-PDO. The conversion done makes it necessary the addition of cysteine to the culture medium. Five experiments were performed with cysteine at five concentrations to verify which is the optimum concentration that does not affect conversion of glycerol into 1,3-PDO. The concentrations used were 0.05, 0.10, 0.15, 0.20 and 0.25 gL-1. The yields were 15, 20, 26, 35 and 28 % respectively. According to the results it is concluded that the optimum cysteine concentration for 1,3-PDO production is 0.20 g.L-1.
Conjugation of Cholesterol to HIV-1 Fusion Inhibitor C34 Increases Peptide-Membrane Interactions Potentiating Its Action
Axel Hollmann, Pedro M. Matos, Marcelo T. Augusto, Miguel A. R. B. Castanho, Nuno C. Santos
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060302
Abstract: Recently, the covalent binding of a cholesterol moiety to a classical HIV-1 fusion inhibitor peptide, C34, was shown to potentiate its antiviral activity. Our purpose was to evaluate the interaction of cholesterol-conjugated and native C34 with membrane model systems and human blood cells to understand the effects of this derivatization. Lipid vesicles and monolayers with defined compositions were used as model membranes. C34-cholesterol partitions more to fluid phase membranes that mimic biological membranes. Importantly, there is a preference of the conjugate for liquid ordered membranes, rich in cholesterol and/or sphingomyelin, as observed both from partition and surface pressure studies. In human erythrocytes and peripheral blood mononuclear cells (PBMC), C34-cholesterol significantly decreases the membrane dipole potential. In PBMC, the conjugate was 14- and 115-fold more membranotropic than T-1249 and enfuvirtide, respectively. C34 or cholesterol alone did not show significant membrane activity. The enhanced interaction of C34-cholesterol with biological membranes correlates with its higher antiviral potency. Higher partitions for lipid-raft like compositions direct the drug to the receptor-rich domains where membrane fusion is likely to occur. This intermediary membrane binding step may facilitate the drug delivery to gp41 in its pre-fusion state.
Carcinoma adenóide quístico recorrente: Revis?o a propósito de um caso clínico
Murinello,Nicole; Vitorino,M Emília; Matos,Cristina; Correia,José Manuel; Lima,Manuela; Baptista,Pedro; Lino,José Sena; Nogueira,Fernando;
Revista Portuguesa de Pneumologia , 2009,
Abstract: the adenoid cystic carcinoma is a malignant epithelial glandular type neoplasia, occurring frequently in the salivary and mammary glands, and rarely in the lung, and is responsible for 0.2% of lung tumours. these tumours present a slow growth and prolonged clinical course, and are characterised by their infiltrative nature and tendency towards late local recurrence. the authors present a case of a woman with adenoid cystic lung carcinoma diagnosed after investigation of a lung nodule, submitted to surgical resection with curative intention, whose follow -up identified late recurrence, 9 years after surgery. the present case emphasises the need for a prolonged surveillance, due to the potential late recurrence of this kind of tumour. the article reviews clinical and pathological features of lung adenoid cystic carcinoma, as well as therapeutic options, namely for prevention of recurrence.
Electron-lattice interaction and structural stability of the oxy-borate Co3O2BO3
M. Matos
Physics , 2010,
Abstract: A theoretical study is carried out in the homometallic mixed valent ludwigite Co3O2BO3 using a modified tight binding methodology. The study focuses on the electronic properties of bulk, 1D and molecular units to describe differences between Co3O2BO3 and another homometallic ludwigite, Fe3O2BO3. The latter is known to present a structural instability which has not been found in Co3O2BO3. Our results show that bulk band structures present no significant differences. Differences are found in the calculation of 1D stripes formed by 3+ 2+ 3+ triads, owed to different 3d occupancy of Fe and Co cations. Conditions for 1D semiconducting transport observed in Fe3O2BO3 are not present in Co3O2BO3. More important differences were found to be related to local octahedral geometry. Larger distortions in Co3O2BO3 lead to higher 2+ 3+ hopping barriers in the triads and consequent localization of charge. In Fe3O2BO3, site equivalence provides easy paths for inter-cation hopping. The present results indicate that local geometry of the cation sites is the main cause of differences in these two compounds; dimerization in the triads, which characterizes the structural change in Fe3O2BO3, could be structurally hindered in Co3O2BO3. An analogy is made with two mixed-valent warwickites, Fe2OBO3 and Mn2OBO3, which show the same structural stability/site equivalence relationship.
Compuls?o ao trabalho ou emancipa??o pelo trabalho? Para um debate sobre as políticas activas de emprego
Hespanha, Pedro;Matos, Ana Raquel;
Sociologias , 2000, DOI: 10.1590/S1517-45222000000200005
Abstract: in portugal, the mandatory availability of unemployed workers to accept a "convenient" job was created in 1985, but only from 1989 onwards it has given rise to a clearer policy of activating workers on workfare. more recently, from 1996 on, the rendimento mínimo garantido (minimum guaranteed earnings) has forced the beneficiaries to be available to take a job or a professional training activity.
Characterization of harmonic and subharmonic functions via mean-value properties
Pedro Freitas,Joao Palhoto Matos
Mathematics , 2001,
Abstract: We give a characterization of harmonic and subharmonic functions in terms of their mean values in balls and on spheres. This includes the converse of an inequality of Beardon's for subharmonic functions. We also obtain integral inequalities of Harnack type between these two means in general domains.
Some photosynthetic and growth responses of Annona glabra L. seedlings to soil flooding
Mielke, Marcelo S.;Matos, Elyabe M.;Couto, Virginia B.;Almeida, Alex-Alan F. de;Gomes, Fábio P.;Mangabeira, Pedro Antonio Oliveira;
Acta Botanica Brasilica , 2005, DOI: 10.1590/S0102-33062005000400025
Abstract: an experiment was conducted with the aim to analyze the effects of soil flooding and leaf position on net primary productivity and whole plant carbon balance of annona glabra l. (annonaceae) seedlings, a highly flood-tolerant tree, native to the tropical americas. all seedlings survived a period of 56 days of flooding without symptoms of stress. flooding induced significant increments in root, stem and whole-plant biomass (p <0.01), and in the root:shoot mass ratio (p <0.05). measurements of leaf gas exchange were conducted at days four, 11, 18 and 56 after flooding, on the first (l1), fourth (l4) and seventh (l7) fully expanded leaves from the apex of each seedling. the mean values of stomatal conductance to water vapour (gs) and net photosynthetic rate (a) in the control seedlings were around 0.26 mol m-2s-1 and 8.8 μmol m-2s-1, respectively. significant reductions (p <0.05) in a were observed from l1 to l7 in controls at all four days of measurements. reductions in a with increasing leaf age also ocurred for flooded plants, but only at days four and 18. flooding induced significant changes in gs (p <0.05), reaching 65% of controls at day four but 152% of controls at day 56. based on the results we conclude that the high survival and growth rates of a. glabra seedlings are directly related to the capacity to mantain a high stomatal conductance and net photosynthetic rate under soil flooding.
Tratamento cirúrgico por via anterior na mielopatia cervical espondilótica com seguimento mínimo de dez anos
Pinto, Rui Peixoto;Oliveira, José;Matos, Rui;Neves, Nuno;Silva, Manuel Ribeiro da;Rodrigues, Pedro Cacho;Barros, Rui M;Cabral, Abel Trigo;
Coluna/Columna , 2010, DOI: 10.1590/S1808-18512010000200014
Abstract: objective: cervical spondylotic myelopathy (csm) is a common cause of spinal cord dysfunction in the adult population. the treatment implies early surgical decompression. the objective was to present a retrospective study of anterior decompression and arthrodesis for csm with a minimal ten years follow-up. methods: patients operated between january 1990 and december 1994 were evaluated for sex, age, number of levels operated, functional evaluation with nurick scale preoperatively, one year after surgery and at the final revision that took place in 2004, evidence of consolidation and complications. results: 91 patients were evaluated, 69 male, 22 female, with a mean age of 56.6 years (42-86) and mean follow-up of 11.9 years. five deaths occurred: three patients died in the immediate postoperative period, one in the first year and one during the follow-up. a mean of 2.7±1.0 levels for patient was performed (1-4). the mean value of preoperative nurick was 3.8±0.9. there was a significant improvement in neurological condition after one year (2.2±1.1; p<0.001), and between preoperative period and final evaluation (2.3±1.2; p<0.001). the degradation between the first year and the final evaluation was statistically significant (p=0.004). there was a strong correlation between age and the number of operated levels (r=0.391; p=0.01), age and initial neurologic status (r=0.238; p=0.05), initial neurological status and number of operated levels (r=0.251; p=0.05) and sex and number of operated levels, with women being operated for more levels (r=0.208; p=0.05). there was also a stronger neurological deterioration between the first year and the final follow-up in young patients when compared to older ones (r=0.25; p=0.05). there is a strong relation between the first year improvement and the final improvement (r=0.838, p=0.01). there was a 100% rate of consolidation. conclusion: in csm, a significant neurological improvement can be expected with surgery, and despite a clinical d
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