Federal University of Roraima

About: Federal University of Roraima is a based out in . It is known for research contribution in the topics: Population & Thermogravimetry. The organization has 981 authors who have published 1218 publications receiving 7849 citations. The organization is also known as: Federal University of Roraima.

Evolution and epidemic spread of SARS-CoV-2 in Brazil.

Abstract: Brazil currently has one of the fastest-growing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemics in the world. Because of limited available data, assessments of the impact of nonpharmaceutical interventions (NPIs) on this virus spread remain challenging. Using a mobility-driven transmission model, we show that NPIs reduced the reproduction number from >3 to 1 to 1.6 in Sao Paulo and Rio de Janeiro. Sequencing of 427 new genomes and analysis of a geographically representative genomic dataset identified >100 international virus introductions in Brazil. We estimate that most (76%) of the Brazilian strains fell in three clades that were introduced from Europe between 22 February and 11 March 2020. During the early epidemic phase, we found that SARS-CoV-2 spread mostly locally and within state borders. After this period, despite sharp decreases in air travel, we estimated multiple exportations from large urban centers that coincided with a 25% increase in average traveled distances in national flights. This study sheds new light on the epidemic transmission and evolutionary trajectories of SARS-CoV-2 lineages in Brazil and provides evidence that current interventions remain insufficient to keep virus transmission under control in this country.

Graphene to graphane: a theoretical study.

Abstract: Graphane is a two-dimensional system consisting of a single layer of fully saturated (sp3 hybridization) carbon atoms. In an ideal graphane structure C–H bonds exhibit an alternating pattern (up and down with relation to the plane defined by the carbon atoms). In this work we have investigated, using ab initio and reactive molecular dynamics simulations, the role of H frustration (breaking the H atoms' up and down alternating pattern) in graphane-like structures. Our results show that a significant percentage of uncorrelated H frustrated domains are formed in the early stages of the hydrogenation process leading to membrane shrinkage and extensive membrane corrugations. These results also suggest that large domains of perfect graphane-like structures are unlikely to be formed, as H frustrated domains are always present.

The study of cardiovascular risk in adolescents – ERICA: rationale, design and sample characteristics of a national survey examining cardiovascular risk factor profile in Brazilian adolescents

Abstract: The Study of Cardiovascular Risk in Adolescents (Portuguese acronym, “ERICA”) is a multicenter, school-based country-wide cross-sectional study funded by the Brazilian Ministry of Health, which aims at estimating the prevalence of cardiovascular risk factors, including those included in the definition of the metabolic syndrome, in a random sample of adolescents aged 12 to 17 years in Brazilian cities with more than 100,000 inhabitants. Approximately 85,000 students were assessed in public and private schools. Brazil is a continental country with a heterogeneous population of 190 million living in its five main geographic regions (North, Northeast, Midwest, South and Southeast). ERICA is a pioneering study that will assess the prevalence rates of cardiovascular risk factors in Brazilian adolescents using a sample with national and regional representativeness. This paper describes the rationale, design and procedures of ERICA.

Color, phenolic and flavonoid content, and antioxidant activity of honey from Roraima, Brazil

Abstract: The total phenolic and flavonoid content, color, and antioxidant activity were evaluated from ten honey samples from Apis mellifera L. collected from Roraima State, Brazil. The total phenolic content was determined using the Folin-Ciocalteu reagent and ranged from 250 to 548 mg gallic acid kg –1 of honey. The total flavonoid content was obtained using two methods: total flavones/flavonols were determined with aluminum chloride, and flavonones/dihydroflavonols were determined with 2,4-dinitrophenylhydrazine. The results ranged from 9 to 48.6 mg of quercetine kg –1 of honey and 1805 to 2606 mg of pinocembrin kg –1 of honey, respectively. Antioxidant activity was measured with 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavengers, and the results of the IC 50 ranged from 3.17 to 8.79 mg/mL. Statistical analysis demonstrated positive correlations between color intensity, flavone and flavonol content, and phenolic content and negative correlations with antioxidant capacity.

Diversity and physiological characterization of D-xylose-fermenting yeasts isolated from the Brazilian Amazonian Forest.

Abstract: Background This study is the first to investigate the Brazilian Amazonian Forest to identify new D-xylose-fermenting yeasts that might potentially be used in the production of ethanol from sugarcane bagasse hemicellulosic hydrolysates.