Ciências da natureza e interdisciplinaridade: a percepção dos estudantes sobre questões de avaliações de larga escala

Buscando fornecer subsídios para o entendimento a respeito da construção e utilização do conhecimento químico e reflexões sobre a forma como ele é ensinado, este trabalho investiga um grupo de dez doutorandos em química de uma Universidade pública do Brasil. A investigação se baseou em dois grupos de entrevistas, analisadas de forma qualitativa, criando-se categorias para codificação das concepções dos químicos em diversos temas. Neste trabalho, são expostos e discutidos os conteúdos das falas deste grupo de pós-graduandos a respeito de suas concepções realistas. A partir desses dados, e dialogando com referenciais da filosofia e do ensino de química, apresentamos apontamentos sobre aspectos peculiares ao fazer e ensinar química

Characterization of Systemic Disease Development and Paw Inflammation in a Susceptible Mouse Model of Mayaro Virus Infection and Validation Using X-ray Synchrotron Microtomography

Mayaro virus (MAYV) is an emerging arthropod-borne virus endemic in Latin America and the causative agent of arthritogenic febrile disease. Mayaro fever is poorly understood; thus, we established an in vivo model of infection in susceptible type-I interferon receptor-deficient mice (IFNAR−/−) to characterize the disease. MAYV inoculations in the hind paws of IFNAR−/− mice result in visible paw inflammation, evolve into a disseminated infection and involve the activation of immune responses and inflammation. The histological analysis of inflamed paws indicated edema at the dermis and between muscle fibers and ligaments. Paw edema affected multiple tissues and was associated with MAYV replication, the local production of CXCL1 and the recruitment of granulocytes and mononuclear leukocytes to muscle. We developed a semi-automated X-ray microtomography method to visualize both soft tissue and bone, allowing for the quantification of MAYV-induced paw edema in 3D with a voxel size of 69 µm3. The results confirmed early edema onset and spreading through multiple tissues in inoculated paws. In conclusion, we detailed features of MAYV-induced systemic disease and the manifestation of paw edema in a mouse model extensively used to study infection with alphaviruses. The participation of lymphocytes and neutrophils and expression of CXCL1 are key features in both systemic and local manifestations of MAYV disease

Structural studies of Helicase NS3 variants from Hepatitis C virus genotype 3 in virological sustained responder and non-responder patients

<p>Abstract</p> <p>Background</p> <p>About 130 million people are infected with the hepatitis C virus (HCV) worldwide, but effective treatment options are not yet available. One of the most promising targets for antiviral therapy is nonstructural protein 3 (NS3). To identify possible changes in the structure of NS3 associated with virological sustained response or non-response of patients, a model was constructed for each helicase NS3 protein coding sequence. From this, the goal was to verify the interaction between helicases variants and their ligands.</p> <p>Findings</p> <p>Evidence was found that the NS3 helicase portion of non-responder patients contained substitutions in its ATP and RNA binding sites. K210E substitution can cause an imbalance in the distribution of loads, leading to a decrease in the number of ligations between the essential amino acids required for the hydrolysis of ATP. W501R substitution causes an imbalance in the distribution of loads, leading and forcing the RNA to interact with the amino acid Thr269, but not preventing binding of ribavirin inhibitor.</p> <p>Conclusions</p> <p>Useful information is provided on the genetic profiling of the HCV genotype 3, specifically the coding region of the NS3 protein, improving our understanding of the viral genome and the regions of its protein catalytic site.</p

Electrocatalysts based on carbon nanotubes: application towastewater treatments

The increasing awareness of water pollution with organic compounds, such as dyes, and their long term effects has encouraged intensive efforts towards pollution abatement. Electrochemical oxidation may constitute an alternative route to the existing methods. Electricity may substitute some toxic redox agents and may permit the oxidation of pollutants in mild conditions i.e. ambient temperature and atmospheric pressure. In recent years there has been increasing interest in multiwalled carbon nanotubes (CNTs) as heterogeneous catalyst supports [1] owing to their high surface area and high electrical conductivity. These peculiar characteristics qualify CNTs as adequate electrocatalysts or as catalyst support materials for the oxidative degradation of organic pollutants in wastewater [2]. In this context the electrochemical oxidation of some refractory compounds like oxalic and oxamic acids, some organic dyes and pesticides was investigated on mono and bi-metallic catalysts supported on multiwalled carbon nanotubes (CNT) aiming at the total transformation of these compounds into carbon dioxide and water. The electrochemical performance of metallic electrocatalysts for nitrate reduction in wastewater was also evaluated having in mind a paired electrolytic process. The electroreactivity of the pollutants on selected electrocatalysts was studied by cyclic voltammetry. Kinetic parameters of the reactions were also determined using this last technique. Exhaustive electrolyses were carried out to determine the mineralization rates and the product distribution. Finally the use of CNT and metal modified CNT as support material for anodic biofilm in microbial fuel cells was studied

RESPOSTA IMUNE INESPECÍFICA DE ANIMAIS ECTOTÉRMICOS ANTÁRTICOS SOB TEMPERATURAS POLARES

This review presents data on nonspecific immune system of Antarctic metazoans poekiloterms. The phagocytosis, inflammation and wound repair were analysed in Antarctic animals, the big head fish (Notothenia coriiceps = N. neglecta), Antarctic starfish (Odontaster validus) and in Antarctic sea urchin (Sterechinus neumayeri).Esta revisão tem por objetivo apresentar os dados sobre a imunidade inespecífica de metazoários pecilotérmicos antárticos obtidos por nosso grupo de pesquisa com animais antárticos. Trataremos em particular dos processos de fagocitose, inflamação e cicatrização em peixes antárticos popularmente chamados “cabeçudas” (Notothenia coriiceps = N. neglecta), em estrelas-do-mar antárticas (Odontaster validus) e em ouriços-do-mar antárticos (Sterechinus neumayeri)

Spatio-Temporal Tracking and Phylodynamics of an Urban Dengue 3 Outbreak in São Paulo, Brazil

The dengue virus has a single-stranded positive-sense RNA genome of ∼10.700 nucleotides with a single open reading frame that encodes three structural (C, prM, and E) and seven nonstructural (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins. It possesses four antigenically distinct serotypes (DENV 1–4). Many phylogenetic studies address particularities of the different serotypes using convenience samples that are not conducive to a spatio-temporal analysis in a single urban setting. We describe the pattern of spread of distinct lineages of DENV-3 circulating in São José do Rio Preto, Brazil, during 2006. Blood samples from patients presenting dengue-like symptoms were collected for DENV testing. We performed M-N-PCR using primers based on NS5 for virus detection and identification. The fragments were purified from PCR mixtures and sequenced. The positive dengue cases were geo-coded. To type the sequenced samples, 52 reference sequences were aligned. The dataset generated was used for iterative phylogenetic reconstruction with the maximum likelihood criterion. The best demographic model, the rate of growth, rate of evolutionary change, and Time to Most Recent Common Ancestor (TMRCA) were estimated. The basic reproductive rate during the epidemics was estimated. We obtained sequences from 82 patients among 174 blood samples. We were able to geo-code 46 sequences. The alignment generated a 399-nucleotide-long dataset with 134 taxa. The phylogenetic analysis indicated that all samples were of DENV-3 and related to strains circulating on the isle of Martinique in 2000–2001. Sixty DENV-3 from São José do Rio Preto formed a monophyletic group (lineage 1), closely related to the remaining 22 isolates (lineage 2). We assumed that these lineages appeared before 2006 in different occasions. By transforming the inferred exponential growth rates into the basic reproductive rate, we obtained values for lineage 1 of R0 = 1.53 and values for lineage 2 of R0 = 1.13. Under the exponential model, TMRCA of lineage 1 dated 1 year and lineage 2 dated 3.4 years before the last sampling. The possibility of inferring the spatio-temporal dynamics from genetic data has been generally little explored, and it may shed light on DENV circulation. The use of both geographic and temporally structured phylogenetic data provided a detailed view on the spread of at least two dengue viral strains in a populated urban area