Impact of content and length of curauá fibers on mechanical behavior of extruded cementitious composites: Analysis of variance

[EN] The use of composite materials in construction has grown considerably in recent years, such as cementitious matrices and concrete reinforced with fibers. The vegetable fibers have become an alternative due to its abundance, low cost and low energy consumption for its production, and appropriate properties mechanical. Curauá fiber is a plant native from Amazonas harvested manually in commercial farming and it is used in the manufacture of ropes and baskets or as reinforcement in composite with organic matrix of components for cars, buses and trucks. On the other hand, the extrusion process can produce composites with high-density matrix with fibers, low permeability and good interface between fiber and matrix. This process is also compatible with the use of vegetable fibers as raw materials in the production of cost-effective construction elements such as ceiling panels and drywalls. The objective of this research was use the analysis of variance (ANOVA) for evaluating with rigor mathematical the influence of content and length of curauá fibers on the mechanical behavior of the extruded cementitious composites. Composites without fibers and reinforced with 1% and 2% by mass of fibers as well as 6 mm and 10 mm of length these curauá fibers were evaluated. The composites with fibers of 10 mm have showed better mechanical results. Besides, the composites with fibers curauá after 200 accelerated aging cycles were better than one non-aging.The authors acknowledge the financial support provided by Brazilian Agencies: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Grant nº 2013/03823-8 and 2012/51467-3); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Grant nº 3886/2014); and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Grant nº 406429/2015 and 312151/2016-0). The authors thank the Brazilian companies Fibria S.A., Infibra S.A. and Imbralit Ltda. for technical support to the development of this work.Teixeria, R.; Santos, S.; Christoforo, A.; Paya Bernabeu, JJ.; Savastano Jr., H.; Rocco Lhar, F. (2019). Impact of content and length of curauá fibers on mechanical behavior of extruded cementitious composites: Analysis of variance. Cement and Concrete Composites. 102:134-144. https://doi.org/10.1016/j.cemconcomp.2019.04.022S13414410

Recent advances in psychoneuroimmunology: inflammation in psychiatric disorders

Psychiatric disorders are common and complex and their precise biological underpinnings remain elusive. Multiple epidemiological, molecular, genetic and gene expression studies suggest that immune system dysfunction may contribute to the risk for developing psychiatric disorders including schizophrenia, bipolar disorder, and major depressive disorder. However, the precise mechanisms by which inflammation-related events confer such risk are unclear. In this review, we examine the peripheral and central evidence for inflammation in psychiatric disorders and the potential molecular mechanisms implicated including inhibition of neurogenesis, apoptosis, the HPA-axis, the role of brain-derived neurotrophic factor and the interplay between the glutamatergic, dopaminergic and serotonergic neurotransmitter systems