Reutilização de material fresado em camadas estruturais de pavimento : novas perspectivas

Na actualidade, a crescente preocupação com a protecção ambiental, que se verifica em todas as áreas, leva a que, a nível da Engenharia Rodoviária, sejam já utilizadas diversas técnicas de reciclagem de subprodutos resultantes de trabalhos de beneficiação e reforço de pavimentos flexíveis. Neste artigo enquadra-se o processo de reutilização de materiais recorrendo à mistura de material fresado com pó e cimento, dentro dos processos de reciclagem de pavimentos e apresentam-se resultados que permitem concluir que a técnica pode constituir uma alternativa à reutilização de subprodutos da construção, em substituição de camadas granulares de pavimento

Contribution for the reuse of rap material in pavements structural layers

O objectivo principal deste artigo é promover a utilização de material fresado em camadas estruturais de pavimento, reutilizando materiais provenientes da reconstrução de camadas de pavimentos flexíveis. Os resultados laboratoriais realizados sobre misturas de material fresado, pó de pedra e cimento (FPC) permitem concluir que uma camada de sub-base de pavimento flexível realizada com esta mistura, pode resultar numa camada de elevada resistência. A técnica é económica e ambientalmente justificada, dado que constitui uma solução para a reutilização de um subproduto da construção, reduzindo a necessidade de utilizar novos agregados. Por outro lado, o aumento da capacidade resistente da camada de sub-base realizada com FPC, pode traduzir-se na possibilidade de diminuir a espessura das restantes camadas de pavimento, reduzindo o consumo de novos agregados e ligantes betuminosos.The main purpose of this article is to promote the use of RAP (Reclaimed Asphalt Pavement) in pavement structural layers, reusing material produced by the reconstruction of flexible pavements layers. Laboratorial results made on mixtures of RAP material, stone powder and cement (FPC) allow concluding that a pavement sub-base layer made with this mixture can constitute a layer with an improved resistance. The technique is economic and environmentally justified, thus it represents a solution for the reuse of a construction by-product, reducing the use of new aggregates. By the other hand, the increase of resistance of the sub-base layer made with FPC, can allow reducing the thickness of other layers, reducing the consumption of new aggregates and bituminous binders

Human toxocariasis: contribution by Brazilian researchers

In the present paper the main aspects of the natural history of human infection by Toxocara larvae that occasionally result in the occurrence of visceral and/or ocular larva migrans syndrome were reviewed. The contribution by Brazilian researchers was emphasized, especially the staff of the Tropical Medicine Institute of São Paulo (IMT)

Human N-acetyltransferase 2 (NAT2) gene variability in Brazilian populations from different geographical areas

Introduction: Several polymorphisms altering the NAT2 activity have already been identified. The geographical distribution of NAT2 variants has been extensively studied and has been demonstrated to vary significantly among different ethnic population. Here, we describe the genetic variability of human N-acetyltransferase 2 (NAT2) gene and the predominant genotype-deduced acetylation profiles of Brazilians.Methods: A total of 964 individuals, from five geographical different regions, were genotyped for NAT2 by sequencing the entire coding exon.Results: Twenty-three previously described NAT2 single nucleotide polymorphisms (SNPs) were identified, including the seven most common ones globally (c.191G>A, c.282C>T, c.341T>C, c.481C>T, c.590G>A, c.803A>G and c.857G>A). The main allelic groups were NAT2*5 (36%) and NAT2*6 (18.2%), followed to the reference allele NAT2*4 (20.4%). Combined into genotypes, the most prevalent allelic groups were NAT2*5/*5 (14.6%), NAT2*5/*6 (11.9%) and NAT2*6/*6 (6.2%). The genotype deduced NAT2 slow acetylation phenotype was predominant but showed significant variability between geographical regions. The prevalence of slow acetylation phenotype was higher in the Northeast, North and Midwest (51.3%, 45.5% and 41.5%, respectively) of the country. In the Southeast, the intermediate acetylation phenotype was the most prevalent (40.3%) and, in the South, the prevalence of rapid acetylation phenotype was significantly higher (36.7%), when compared to other Brazilian states (p < 0.0001). Comparison of the predicted acetylation profile among regions showed homogeneity among the North and Northeast but was significantly different when compared to the Southeast (p = 0.0396). The Southern region was significantly different from all other regions (p < 0.0001).Discussion: This study contributes not only to current knowledge of the NAT2 population genetic diversity in different geographical regions of Brazil, but also to the reconstruction of a more accurate phenotypic picture of NAT2 acetylator profiles in those regions

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field