The Venoarteriolar Reflex Significantly Reduces Contralateral Perfusion as Part of the Lower Limb Circulatory Homeostasis in vivo

Perfusion at microvascular level involves the contribution of both local and central regulators, under a complex vascular signaling frame. The venoarteriolar reflex (VAR) is one of such regulatory responses, of particular relevance in the lower limb to prevent edema. Although known for quite some time, many of the complex interactions involving all of these regulatory mechanisms still need clarification. Our objective was to look deeper into VAR through modern photoplethymography (PPG). Twelve healthy subjects (both sexes, 26.0 ± 5.0 y.o.) were enrolled in this study after informed written consent. Subjects were submitted to a leg lowering maneuver while lying supine to evoke the VAR, involving three phases–10 min baseline register, both legs extended, 10 min challenge, with one randomly chosen leg (test) pending 50 cm below heart level, while the contralateral (control) remained in place, and 10 minutes recovery, resuming the initial position. PPG signals were collected from both feet and treated by the wavelet transform (WT) revealing six spectral bands in frequency intervals comprising the cardiac [1.6–0.7 Hz], respiratory [0.4–0.26 Hz], myogenic [0.26–0.1 Hz], neurogenic/sympathetic [0.1–0.045 Hz], endothelial NO-dependent (NOd) [0.045–0.015 Hz], and NO-independent (NOi) [0.015–0.007 Hz] activities. For the first time, this approach revealed that, with VAR, perfusion significantly decreased in both limbs, although the change was more pronounced in the test foot. Here, a significant decrease in myogenic, neurogenic and NOd, were noted, while the control foot recorded a decrease in neurogenic and an increase in NOd. These results confirm the utility of WT spectral analysis for flowmotion. Further, it strongly suggests that VAR results from a complex cooperation between local myogenic-endothelial responses, where a central neurogenic reflex might also be involved

Waste polymers recycling in high performance asphalt mixtures

Building a road pavement requires large amounts of constituent materials, whose extraction can lead to the devastation of natural resources and causes negative impacts on the environment. As aggregates comprise nearly 90% of asphalt mixtures, their partial substitution by waste thermosetting polymers (12 million tons of waste polymers are presently mislaid into landfills, every year, in Europe) can be considered as a sustainable technology, given that an equivalent performance can be assured. Thus, this study aims on evaluating possible advantages of introducing polyethylene based wastes in asphalt mixtures, namely high density polyethylene (HDPE) and cross-linked polyethylene (PEX), incorporating HDPE as a bitumen modifier and PEX as partial substitute of the aggregates. The laboratory tests carried out in this work showed that the use of HDPE significantly improves the behavior of the asphalt binder/mixture. The use of PEX considerably decreases the density of the mixtures, which can be attractive to lighten structures. The mixtures with PEX have similar performance to the conventional one in terms of water sensitivity, improving the permanent deformation resistance and reducing the temperature susceptibility. In brief, the mixtures incorporating waste polymers could be considered a good technical and environmental alternative for paving works.Portuguese Foundation for Science and Technology (FCT) in the scope of the Strategic Project UI 4047 2011‐201

Indicadores biofísicos de sistemas agroflorestais.

Palestra

Effectiveness of the flipped classroom methodology In the performance of higher education students: systematic review with meta-analysis

Introduction: The methodology Flipped Classroom (FC) consists in individual activities that the student has to do at home through the use of technologies which help the student to prepare for class, and during classes, activities are performed as more dynamic classes centered on the student. Through the years, the success has reached the maximum levels of performance and satisfaction in the teaching sessions in different areas of education compared to the classical methods, and there are no conclusive and considerable studies that compile and analyze this information succinctly. Objective: To analyze experimental and quasi-experimental studies that evaluate the methodology database in FC in performance and student satisfaction in comparison with the expository methodology. Methodology: This article is a systematic review that analyzes the randomized controlled trial (RCT) and Quasi-experimental studies selected with the methodology FC, which measures the efficacy through the results achieved in the realization and evaluation of the students. These articles were found in EBSCOhost and PubMed. Results: We selected 41 articles, that fulfilled all inclusion criteria established by the authors, for the accomplishment of this systematic review. Discussion: The results of our meta-analysis, both RCTs and quasi-experimental studies, point to a better effectiveness of the FC methodology compared to the expository methodology in academic performance. However, there is a heterogeneity in planned and developed activities during class, which means that our conclusions can’t be generalized. The poor methodological quality of the included studies, especially quasi-experimental studies, does not allow our conclusions about efficacy to be vigorous. Nevertheless, based on these first promising data, it seems to us that this methodology offers learning opportunities that aren’t possible in a classroom based on lectures and subject matter exposition. Conclusion: Although the articles selected have poor methodological quality, and it is necessary more rigorous investigations on this methodology, we believe that the FC methodology could revolutionize teaching methods and replace traditional teaching, which is so deeply rooted in today's society and doesn’t seems to favor the achievement of transversal competences.info:eu-repo/semantics/publishedVersio

Avaliação de estruturas de pavimentos rodoviários através de pista e simulador de ensaios acelerados à escala real

Os ensaios acelerados de pavimentos rodoviários consistem na aplicação controlada de um carregamento vertical, através de uma roda normalizada que circula a uma velocidade controlada, simulando as cargas reais introduzidas pelo tráfego pesado. Em condições de temperatura e humidade controladas, os ensaios acelerados permitem simular num período de tempo reduzido as ações a que um pavimento está sujeito ao longo da sua vida útil. No âmbito do Projeto Tropical-PAV foi construída no LNEC uma pista de ensaios à escala real e instalado um Simulador de Ensaios Acelerados sobre Pavimentos Rodoviários possibilitando o estudo e a validação de técnicas de construção e/ou reabilitação de pavimentos rodoviários. No presente trabalho é feita uma apresentação geral dos ensaios acelerados sobre pavimentos rodoviários e em particular do Projeto de I&D Tropical-PAV.Quadro de Referência Estratégica Nacional e à entidade financiadora Agência Nacional da Inovação pelo financiamento ao projeto número 38915 Projeto de I&D Tropical-PA

Soluções de pavimentos rodoviários para países com climas tropicais – projeto de I&D tropical-PAV

Algumas empresas do setor da construção que integram a Plataforma Tecnológica Portuguesa da Construção (PTPC) decidiram promover a cooperação tecnológica entre si e com as entidades do Sistema Científico e Tecnológico Nacional (SCTN) para o desenvolvimento de novas soluções de pavimentação rodoviária para aplicação em países de clima tropical, nomeadamente ao nível das misturas betuminosas e das camadas de solocimento. O objetivo do projeto foi permitir a eventual criação de uma solução de pavimentação inovadora através do desenvolvimento de uma mistura betuminosa e de uma mistura de solo-cimento formuladas com base em ensaios empíricos e de desempenho, à escala laboratorial e, posteriormente, validando esse desempenho num ensaio à escala real recorrendo a uma Pista de Ensaios Acelerados de Pavimentos, onde foram aplicados carregamentos idênticos às solicitações que serão alvo ao longo do seu período de vida útil. Esta Pista de Ensaios Acelerados de Pavimentos construída no âmbito deste projeto integra um protótipo de um simulador de tráfego, que reproduz a simulação do tipo de solicitação a que um pavimento habitualmente está sujeito

Physicochemical properties and cell viability of shrimp chitosan films as affected by film casting solvents. I-potential use as wound dressing

: Chitosan solubility in aqueous organic acids has been widely investigated. However, most of the previous works have been done with plasticized chitosan films and using acetic acid as the film casting solvent. In addition, the properties of these films varied among studies, since they are influenced by different factors such as the chitin source used to produce chitosan, the processing variables involved in the conversion of chitin into chitosan, chitosan properties, types of acids used to dissolve chitosan, types and amounts of plasticizers and the film preparation method. Therefore, this work aimed to prepare chitosan films by the solvent casting method, using chitosan derived from Litopenaeus vannamei shrimp shell waste, and five different organic acids (acetic, lactic, maleic, tartaric, and citric acids) without plasticizer, in order to evaluate the effect of organic acid type and chitosan source on physicochemical properties, degradation and cytotoxicity of these chitosan films. The goal was to select the best suited casting solvent to develop wound dressing from shrimp chitosan films. Shrimp chitosan films were analyzed in terms of their qualitative assessment, thickness, water vapor permeability (WVP), water vapor transmission rate (WVTR), wettability, tensile properties, degradation in phosphate buffered saline (PBS) and cytotoxicity towards human fibroblasts using the resazurin reduction method. Regardless of the acid type employed in film preparation, all films were transparent and slightly yellowish, presented homogeneous surfaces, and the thickness was compatible with the epidermis thickness. However, only the ones prepared with maleic acid presented adequate characteristics of WVP, WVTR, wettability, degradability, cytotoxicity and good tensile properties for future application as a wound dressing material. The findings of this study contributed not only to select the best suited casting solvent to develop chitosan films for wound dressing but also to normalize a solubilization protocol for chitosan, derived from Litopenaeus vannamei shrimp shell waste, which can be used in the pharmaceutical industry.info:eu-repo/semantics/publishedVersio

The European VLF/LF radio network to search for earthquake precursors: setting up and natural/man-made disturbances

In the last years disturbances in VLF/LF radio signals related to seismic activity have been presented. The radio data were collected by receivers located on the ground or on satellites. The ground-based research implies systematic data collection by a network of receivers. Since 2000 the “Pacific VLF network”, conducted by Japanese researchers, has been in operation. During 2008 a radio receiver was developed by the Italian factory Elettronika (Palo del Colle, Bari). The receiver is equipment working in VLF and LF bands. It can monitor 10 frequencies distributed in these bands and, for each of them, it saves the power level. At the beginning of 2009, five receivers were made for the realization of the “European VLF/LF Network”; two were planned for Italy and one for Greece, Turkey and Romania, respectively. In 2010 the network was enlarged to include a new receiver installed in Portugal. In this work, first the receiver and its setting up in the different places are described. Then, several disturbances in the radio signals related to the transmitters, receivers, meteorological/geomagnetic conditions are presented and described