Influence of ageing on the properties of bitumen from asphalt mixtures with recycled concrete aggregates

The reuse of recycled concrete aggregates in new hot-mix asphalt can be a more sustainable method of production, but these mixtures may need a heat treatment before compaction to improve their water sensitivity performance. A direct consequence of this treatment is an increase in the hot-mix asphalt resilient modulus. The aim of this paper is to analyse the effect of ageing on the stiffness of asphalt mixtures with different amounts of recycled concrete aggregates, before and after a heat treatment, which was analysed through the assessment of its bitumen properties. Moreover, this paper also aims to analyse whether the rolling thin-film oven test is able to simulate the ageing effect of the heat treatment. In the laboratory work, a paving grade bitumen B50/70 has been used to produce asphalt mixtures with 0% and 30% recycled concrete aggregates, and the bitumen was later characterised (using penetration, softening point, dynamic viscosity and dynamic shear rheometer tests) in various situations, such as when using virgin bitumen, short-term aged bitumen, aged bitumen after heat treatment (simulated with 4 h of rolling thin-film oven test) and bitumen samples recovered from asphalt mixtures with different production mixes (0% and 30% recycled concrete aggregate) and heat treatment conditions (0 and 4 h of curing time in the oven). Based on the results obtained, it could be concluded that the ageing resulting from the heat treatment is the primary cause of the hot-mix asphalt's increased stiffness, while recycled concrete aggregate content has a small influence. Moreover, it could be concluded that when there is no curing time, the recycled concrete aggregate protects the bitumen against ageing. Additionally, it could be stated that the rolling thin-film test is able to adequately simulate the ageing effect of the heat treatment. Thus, this test is useful for determining the ageing suffered by the bitumen when the recycled concrete aggregate mixture is manufactured using a heat treatment.

Poly-N-acetyl glucosamine expression in Staphylococcus epidermidis biofilm cells affects the immune response and promotes tissue pathology in infected hosts

Staphylococcus epidermidis is a biofilm - forming bacterium and a leading etiological agent of nosocomial infections. The ability to establish biofilms on indwelling medical devices is a key virulence factor for this bacterium. Still, the influence of poly - N - acetyl glucosamine (PNAG), the major component of the extracellular biofilm matrix, in the host immune response has been scarcely studied. Here, t h is influence was assessed in mice challenged i.p. with PNAG - p roducing (WT) and isogenic - mutant lacking PNAG (M10) bacteria grown in biofilm - inducing conditions. Faster bacterial clearance was observed in the mice infected with WT bacteria than in M10 - infected counterparts , which w as accompanied by earlier neutrophil recruitment and higher IL - 6 production. Interestingly, in the WT - infected mice, but not in those infected with M10 , elevated serum IL - 10 was detected . To further study the effe ct of PNAG in the immune response, mice were primed with WT or M10 biofilm bacteria and subsequently infected with WT biofilm - released cells. WT - primed mice presented a higher frequency of splenic IFN - γ + and IL - 17 + CD4 + T cells, and more severe liver patho logy than M10 - primed counterparts. Nevertheless, T reg cells obtained from the WT - primed mice presented a higher suppressive function than those obtained from M10 - primed mice. This effect was abrogated when IL - 10 - deficient mice were similarly primed and infected indicating that PNAG promotes the differentiati on of highly suppressive T reg cells by a mechanism dependent on IL - 10. Altogether, these results provide evidence help ing explain ing the coexistence of inflammation and bacterial persistence often observed in biofilm - originated S. epidermidis infections

A evasão na Universidade Federal do Recôncavo da Bahia: um estudo inicial

A presente investigação é parte integrante do projeto de pesquisa em desenvolvimento para a elaboração da tese de doutoramento. Aporta-se na temática da evasão na educação superior após a utilização do Exame Nacional do Ensino Médio e do Sistema de Seleção Unificada, como mecanismo de acesso às instituições públicas a partir de 2010, tendo como locus da pesquisa a Universidade Federal do Recôncavo da Bahia (UFRB). O objetivo deste texto é analisar os dados preliminares do levantamento quantitativo da evasão dos estudantes nessa instituição. O embasamento teórico discutirá os conceitos interligados de evasão, fracasso e abandono escolar relacionado ao contexto da educação superior bem como as implicações da globalização para o entendimento do fenômeno. A fundamentação será norteada pelos estudos Marchesi & Pérez (2004); Arocão (2000); Tinto (1993) sobre evasão, fracasso escolar e abandono escolar. Também serão analisados os aspectos influenciadores da evasão a partir dos estudos de Bourdieu & Passeron (2014), Coulon (2008), entre outros. Nesta primeira fase da pesquisa, a abordagem metodológica será fundamentalmente de natureza quantitativa, com recurso ao método de análise documental. O estudo focou-se na análise dos ingressantes do período de 2010 a 2013 e identificou os cursos de graduação com maior número de evadidos por nos centros de ensino da UFRB até o segundo período de 2014.. Os resultados preliminares apontam que, dos 9.661 estudantes registrados no período, dos quais 331 concluíram até a data da coleta e 4.839 não estão na instituição o que indica um percentual inicial de 50,1% estudantes evadidos, cujos motivos precisam ser investigados a partir de um enfoque qualitativo.

Portugal

El presente trabajo describe y caracteriza la programación educativa y cultural emitida en 2008 por los cuatro canales televisivos generalistas portugueses: dos canales publicos (R TP 1 y R TP2) y dos canales privados (SIC y TVI). El sistema televisivo portugués no dispone de un servicio de caracter exclusivamente educativo y cultural y, como será posible verificar a lo largo del Informe, algunos de los programas indicados como cal presentan caracteristicas que no són de ámbito estrictamente educativo o cultural.

O poder da linguagem e a heteronormatividade inconsciente: uma leitura comparada entre Lupe Gómez e Adília Lopes

Dissertação de mestrado em Teoria da Literatura e Literaturas Lusófonas

Biotechnological production and application of fructooligosaccharides

Currently, prebiotics are all carbohydrates of relatively short chain length. An important group is the fructooligosaccharides, which are a special kind of prebiotics associated to their selective stimulation of the activity of certain groups of colonic bacteria that have a positive and beneficial effect on intestinal microbiota, reducing incidence of gastrointestinal infections, respiratory and also possessing a recognized bifidogenic effect. Traditionally, these prebiotic compounds have been obtained through extraction processes from some plants, as well as through enzymatic hydrolysis of sucrose. However, different fermentative methods have also been proposed for the production of fructooligosaccharides, such as solid-state fermentation utilizing various agroindustrial by-products. By optimizing the culture parameters, fructooligosaccharides yields and productivity can be improved. The use of immobilized enzymes and cells has also been proposed as being an effective and economic method for large-scale production of fructooligosaccharides. This paper is an overview on the results of recent studies on fructooligosacharides biosynthesis, physicochemical properties, sources, biotechnological production and applications.

Single molecule simulation of diffusion and enzyme kinetics

This work presents a molecular-scale agent-based model for the simulation of enzymatic reactions at experimentally measured concentrations. The model incorporates stochasticity and spatial dependence, using diffusing and reacting particles with physical dimensions. We developed strategies to adjust and validate the enzymatic rates and diffusion coefficients to the information required by the computational agents, i.e., collision efficiency, interaction logic between agents, the time scale associated with interactions (e.g., kinetics), and agent velocity. Also, we tested the impact of molecular location (a source of biological noise) in the speed at which the reactions take place. Simulations were conducted for experimental data on the 2-hydroxymuconate tautomerase (EC 5.3.2.6, UniProt ID Q01468) and the Steroid Delta-isomerase (EC 5.3.3.1, UniProt ID P07445). Obtained results demonstrate that our approach is in accordance to existing experimental data and long-term biophysical and biochemical assumptions.