Validation of a simplified model for the design of masonry infilled frames

The design of masonry infills is an issue that has attracted the attention of several researchers in the past, both from the experimental and analytical points of view. Nevertheless, the results are often questionable due to the large variability of masonry properties, the limited number of tests carried out and the large number of influencing factors. This paper addresses this limitation by using numerical analysis as a simulation of an experimental laboratory, and by performing a sensitivity analysis about the influence of the different influence factors. The modelling approach has been validated using the experimental results of two masonry walls subjected to horizontal loading. The parametric study subsequently carried out allowed to propose a strut-and-tie model that provides a novel simplified expression for the failure of infill walls belonging to frames subjected to horizontal loading. The proposed model is compared with other models available in the literature exhibiting superior performance and constituting a simple and versatile tool for design.CAPES.UFV

Estudo de pórticos metálicos enrijecidos com alvenaria

Este trabalho aborda o estudo experimental e numérico do comportamento de pórticos metálicos preenchidos com painel de alvenaria constituído por blocos de concreto celular autoclavado, levando-se em consideração a contribuição do painel de alvenaria na rigidez global da estrutura. O conjunto pórtico-painel foi submetido à acção de carga horizontal aplicada no eixo da viga superior do pórtico. Foram utilizadas barras de aço lisas, na forma de estribos, soldadas às mesas dos pilares metálicos, denominadas barras de aço “ferro-cabelo”, numa tentativa de retardar o descolamento precoce existente na interface pórtico-painel. A pesquisa consta de uma série de 6 ensaios experimentais do conjunto em escala real, 2 ensaios com o pórtico metálico isolado (sem o painel de preenchimento) e de análises numéricas, onde a alvenaria foi considerada um material não-linear

Influência da relação altura/comprimento de pórticos metálicos na rigidez lateral de estruturas compostas de pórticos preenchidos com alvenaria : avaliação experimental

Uma solução bastante freqüente para preenchimento de pórticos de aço é a utilização de painéis de alvenaria de blocos de concreto celular autoclavados. Esta associação produz efeitos benéficos relacionados à resistência, rigidez e ductilidade da estrutura composta resultante. Neste trabalho apresenta-se um estudo experimental da influência da relação altura/comprimento (H/L) de pórticos metálicos na rigidez de estruturas compostas de pórticos preenchidos com alvenaria. Foram utilizados dois pórticos de aço de perfis soldados, de dimensões em cm 322x275 e 522x275, correspondendo às relações altura/comprimento (H/L) iguais a 0,83 e 0,51, respectivamente. Para preenchimento dos pórticos foram utilizados painéis de blocos de alvenaria estrutural de concreto celular autoclavados, enquanto nas juntas entre blocos e na interface pórtico-painel utilizou-se argamassa colante. O conjunto pórtico-painel foi submetido a uma ação horizontal aplicada no eixo da viga superior do pórtico, que trabalhou em regime elástico, enquanto a alvenaria foi ensaiada até o colapso, a fim de obter o modo de ruptura para a mesma. Os resultados obtidos comprovam que quanto menor a relação H/L dos pórticos preenchidos, menor a rigidez e maior a carga de ruptura por fissuração da diagonal, embora surjam fissuras verticais

Global persistence exponent of the two-dimensional Blume-Capel model

The global persistence exponent $\theta_g$ is calculated for the two-dimensional Blume-Capel model following a quench to the critical point from both disordered states and such with small initial magnetizations. Estimates are obtained for the nonequilibrium critical dynamics on the critical line and at the tricritical point. Ising-like universality is observed along the critical line and a different value $\theta_g =1.080(4)$ is found at the tricritical point.Comment: 7 pages with 3 figure

Targeting the mitochondrial VDAC in hepatocellular carcinoma using a polyclonal antibody-conjugated to a nitrosyl ruthenium complex

The rational design of anti-cancer agents includes a new approach based on ruthenium complexes that can act as nitric oxide (NO) donor agents against specific cellular targets. One of the most studied classes of those compounds is based on bis(bipyridine) ruthenium fragment and its derivative species. In this work, we present the chemical and cytotoxicity properties against the liver hepatocellular carcinoma cell line HepG2 of cis-[RuII(NO+)Cl(dcbpy)2]2− conjugated to a polyclonal antibody IgG (anti-VDAC) recognizing a cell surface marker. UV–visible bands of the ruthenium complex were assigned with the aid of density functional theory, which also allowed estimation of the structures that explain the biological effects of the ruthenium complex–IgG conjugate. The interaction of cis-[RuII(NO+)Cl(dcbpy)2]3− with mitochondria was evaluated due to the potential of these organelles as anti-cancer targets, and considering they interact with the anti-VDAC antibody. The cytotoxicity of cis-[RuII(NO+)Cl(dcbpy)2]3−-anti-VDAC antibody was up to 80% greater in comparison to the free cis-[RuII(NO+)Cl(dcbpy)2]3− complex. We suggest that this effect is due to site-specific interaction of the complex followed by NO release.Fil: Ramos, Loyanne C. B.. Universidade de Sao Paulo; BrasilFil: Rodrigues, Fernando P.. Universidade de Sao Paulo; BrasilFil: Biazzotto, Juliana C.. Universidade de Sao Paulo; BrasilFil: de Paula Machado, Sergio. Universidade Federal do Rio de Janeiro; BrasilFil: Slep, Leonardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Hamblin, Michael R.. Harvard Medical School; Estados UnidosFil: da Silva, Roberto S.. Harvard Medical School; Estados Unidos. Universidade de Sao Paulo; Brasi

MnO2-Ir Nanowires: Combining Ultrasmall Nanoparticle Sizes, O-Vacancies, and Low Noble-Metal Loading with Improved Activities towards the Oxygen Reduction Reaction

"Although clean energy generation utilizing the Oxygen Reduction Reaction (ORR) can be considered a promising strategy, this approach remains challenging by the dependence on high loadings of noble metals, mainly Platinum (Pt). Therefore, efforts have been directed to develop new and efficient electrocatalysts that could decrease the Pt content (e.g., by nanotechnology tools or alloying) or replace them completely in these systems. The present investigation shows that high catalytic activity can be reached towards the ORR by employing 1.8 ± 0.7 nm Ir nanoparticles (NPs) deposited onto MnO2 nanowires surface under low Ir loadings (1.2 wt.%). Interestingly, we observed that the MnO2 -Ir nanohybrid presented high catalytic activity for the ORR close to commercial Pt/C (20.0 wt.% of Pt), indicating that it could obtain efficient performance using a simple synthetic procedure. The MnO2 -Ir electrocatalyst also showed improved stability relative to commercial Pt/C, in which only a slight activity loss was observed after 50 reaction cycles. Considering our findings, the superior performance delivered by the MnO2 -Ir nanohybrid may be related to (i) the significant concentration of reduced Mn3+ species, leading to increased concentration of oxygen vacancies at its surface; (ii) the presence of strong metal-support interactions (SMSI), in which the electronic effect between MnOx and Ir may enhance the ORR process; and (iii) the unique structure comprised by Ir ultrasmall sizes at the nanowire surface that enable the exposure of high energy surface/facets, high surface-to-volume ratios, and their uniform dispersion.

Using of essential oils in the treatment of mice infected with Trypanosoma evansi

Objective. This study aimed to test the effectiveness of copaiba, andiroba and aroeira essential oils for controlling trypanosomosis by Trypanosoma evansi with mice as experimental model. Materials and methods. Sixty-six mice were divided into eleven groups (A to L) with six animals each. Group A was the unique composed by healthy and uninfected animals (negative control). Animals in groups B to L were inoculated with 0.1 mL of blood containing 2.7 x 106 trypanosomes. Group B was used as a positive control without treatment. In experiment were tested copaiba (C, D and E), andiroba (F, G and H) and aroeira (I, J and L) oils at doses of 0.6, 0.8 and 1.0 mL kg-1 to infected mice (T. evansi). Results. These protocols did not provide curative efficacy; however, the mice treated with highest dose of copaiba showed a significant increase in the longevity when compared others groups. Conclusions. Previously in our studies, these essential oils have shown trypanocidal activity in vitro, but when they were tested in vivo in mice infected with T. evansi, this trypanocidal activity, or the curative effect was not found, being only able to prolong the lifespan of the animals treated with copaiba oil

Factors associated with thrombocytopenia in severe leptospirosis (Weil's disease)

OBJECTIVE: This study was conducted to investigate factors associated with thrombocytopenia in a large cohort of patients with leptospirosis in an endemic area. METHODS: This retrospective study included 374 consecutive patients with leptospirosis who were admitted to tertiary hospitals in Fortaleza, Brazil. All patients had a diagnosis of severe leptospirosis (Weil's disease). Acute kidney injury was defined according to the RIFLE criteria. Thrombocytopenia was defined as a platelet coun

A New PRNG Hardware Architecture Based on an Exponential Chaotic Map

Recent works have been claiming efficient hardware architectures, showing a considerable endeavor to implement chaotic maps in the digital domain. However, there is a critical issue with the chaotic degradation in the digital environment due to its finite numeric precision, that it is still an unsettled topic in the research community. Additionally, less attention has been given to synthesize a methodological approach to how to calculate the exponential function in hardware. In this paper, two novel hardware designs to represent the exponential chaotic map have been suggested. We have employed a perturbation method to avoid the chaotic degradation. 64-bit fixed-point and 32-bit floating-point formats were investigated. Moreover, an approximation of Euler's number by a finite series and the Horner's method have been undertaken to further minimize the proposed hardware. Results show that both proposed hardware architectures consume a fewer number of components. The designed systems present a positive Lyapunov exponent, which suggests a chaotic behavior. Ultimately, the NIST SP 800-22 test, the histogram, and the autocorrelation function show that the new hardware architectures present pseudo-random properties

Diagnóstico da pesquisa em biodiversidade no Brasil

Biodiversity is a result of millions of years of biological evolution, and is the component of the system which supports life on our planet. Besides the intrinsic value of each species, all of them as a whole, as well as of the interactions among the species, and their interaction with the physical and chemical environment, result in ecosystem services vital for supporting life on Earth. Because of that, the science of biodiversity is largely recognized as a priority area of scientific investigation both in developed and developing countries. In Brazil, the research on biodiversity can be divided in three parts: 1) discovery and characterization of biodiversity - including marine and human-altered landscapes - systematics and taxonomy; 2) understanding the functioning of ecosystems and environmental services, including in marine and human-altered landscapes; 3) bioprospecting of the chemical diversity of the Brazilian biota.A biodiversidade resulta de milhões de anos de evolução biológica e é o componente do sistema de suporte à vida de nosso planeta. Além do valor intrínseco de cada espécie, seu conjunto, bem como o de interações entre espécies e destas com o meio físico-químico, resultam em serviços ecossistêmicos imprescindíveis para manter a vida na Terra. Sendo assim, a ciência da biodiversidade é amplamente reconhecida como área prioritária de investigação científica, tanto nos países desenvolvidos como naqueles em desenvolvimento. No Brasil, a pesquisa em biodiversidade pode ser dividida em três principais vertentes: 1) descoberta e caracterização da biodiversidade, inclusive marinha e em paisagens alteradas - sistemática e taxonomia; 2) compreensão do funcionamento de ecossistemas e serviços ambientais, inclusive marinhos e em paisagens alteradas; 3) bioprospecção da quimiodiversidade da biota brasileira