1,446 research outputs found
Self-adjusting orthoses design
This paper proposes an approach to the development of a customized 3D printed multi-material cervical
orthosis that combines new production techniques with smart materials and biomimetic structures. It suggests
a lightweight, waterproof, ventilated, hygienic and comfortable orthoses designed specifically for each patient in
collaboration with doctors, additive manufacturing specialists and designers. The combination of innovative production
techniques with smart materials can generate an enhanced product, whose added value can be perceived by
differentiated attributes and applications
Adsorption of two pesticides on a clay surface: a theoretical study
The contamination of water resources with many organic xenobiotic compounds poses a challenge to environmental sciences and technologies [1]. Although in many cases these contaminants are present only in small concentrations, the large variety of such compounds (some of which are classified as priority pollutants) is a matter of concern. Adsorption, alone or as part of a more complex water or wastewater treatment process, has been seen as playing a very important role in the removal of many of these pollutants [2]. In this regard, the choice of adsorbent materials is crucial, which requires an understanding of the details involved in the adsorption of more or less complex organic molecules by a variety of surfaces of different types. In addition to laboratory studies, computational studies may be valuable in this study [3].
MCPA (2-methyl-4-chlorophenoxyacetic acid, a herbicide) and Clofibric acid (2-(4-chlorophenoxy)-2-methylpropanoic, the metabolite of a pharmaceutical, clofibrate, and also a herbicide) are two phenoxy acids that differ only slightly in their structures. However, a quite distinct behavior in adsorption phenomena on clay materials has been observed in past studies [4]. By relating those differences with the molecules' structural features through atomistic computational studies, some insight may be gained into the respective adsorption processes of this type of compounds.
In the present work quantum chemical calculations at density functional theory level have been performed to study the adsorption of MCPA and Clofibric acid by a clay surface model. Since hydration plays an important role for the adsorption process of these species, solvent effects were considered by inclusion of water molecules explicitly into the quantum chemical calculations.
The deprotonated negatively charged species were found to strongly interact with the surface and the distinct behavior of both species upon adsorption was compared with experimental evidences
Multiple Food Allergy
A alergia alimentar múltipla é uma resposta imune adversa a mais do que um alimento.
Quando uma criança é alérgica a vários alimentos, o quadro clínico pode ser grave e a evicção dos alergénios implicados leva a restrições dietéticas importantes.
Descrevemos o caso de uma criança de quatro anos com eczema atópico grave e alergia
alimentar múltipla. Apresentou Imunoglobulina (Ig)E específica positiva aos oito meses para leite, trigo, centeio, cevada, glúten, soja, ovo (gema e clara) e iniciou evicção destes alimentos. Aos 20 meses tentou introduzir trigo, suspendendo após agravamento do eczema atópico. Aos três anos teve reacção anafiláctica após contacto com queijo. Aos quatro anos mantém evicção de leite, ovo, trigo, glúten, cevada e centeio.
As restrições alimentares nestes doentes são grandes, havendo necessidade de controlo
rigoroso dos alimentos ingeridos para evicção de reacções adversas e prevenção de carências nutricionais. É importante a abordagem multidisciplinar
Desenvolvimento e mortalidade larval de Spodoptera frugiperda em folhas de milho tratadas com extrato aquoso de folhas de Azadirachta indica.
Estudou-se o efeito do extrato aquoso de folhas de nim sobre o desenvolvimento e a mortalidade de lagartas recém-eclodidas de Spodoptera frugíperda. Para constatação do efeito de contato e de ingestão, as lagartas foram pulverizadas e as folhas de milho submersas no extrato (10 mg.mL-1) em laboratório e/ou pulverizadas no campo com um pulverizador de CO2-. Partes de folhas de milho tratadas foram colocadas em copos plásticos para alimentar as lagartas e trocadas a cada dois dias. Adjuvantes foram adicionados ao extrato visando melhorar sua aderência às superfícies tratadas. Os parâmetros avaliados foram a mortalidade e o desenvolvimento larval. As folhas de milho submergidas e pulverizadas com o extrato causaram elevada mortalidade (100%) e prejudicaram o desenvolvimento das lagartas sobreviventes. Na avaliação realizada 10 dias após a aplicação, o espalhante adesivo e o óleo de soja misturados ao extrato melhoraram a eficiência deste. A mortalidade das lagartas ocorreu três dias após a aplicação do extrato e a sua pulverização diretamente sobre o inseto não prejudicou o desenvolvimento larvaL. O extrato aquoso de nim mostrou-se com potencial para o controle de S. frugíperda
Mortalidade de lagarta de Spodoptera frugiperda alimentadas com folhas de milho tratadas com extrato aquoso de folhas de nim Azadirachta indica.
O objetivo deste trabalho foi avaliar o efeito do período de alimentação sobre a mortalidade de lagartas de Spodoptera frugiperda, de diferentes idades, alimentadas com folhas de milho tratadas com extrato aquoso de folhas de nim (Azadirachta indica). Dois bioensaios foram conduzidos em laboratório da Embrapa Milho e Sorgo, em Sete Lagoas, MG. No primeiro, lagartas recém-eclodidas foram alimentadas por períodos de um a seis dias, com seções de folhas de milho tratadas com o extrato e, em seguida, alimentadas com folhas não tratadas. No segundo, lagartas com diferentes idades (1 a 13 dias) foram alimentadas com folhas tratadas com o mesmo extrato, durante a fase larval. O extrato de nim foi preparado pela colocação de 150 g de folhas secadas ao ar livre e moídas em 1 L de água destilada. Os dados de mortalidade larval foram submetidos à análise de regressão. Os resultados do primeiro bioensaio mostraram que lagartas recém-eclodidas, alimentadas com folhas de milho tratadas com extrato de nim por um dia, tiveram alta mortalidade (99 a 100%) e impediram que o inseto restabelecesse o seu desenvolvimento normal ao ter acesso ao alimento não tratado, após esse período. Os resultados do segundo bioensaio mostraram que a mortalidade de lagartas com até oito dias (3o ínstar) foi elevada (90%), decrescendo acentuadamente após dez dias de idade
Differential mesenteric fat deposition in bovines fed on silage or concentrate is independent of glycerol membrane permeability
© The Animal Consortium 2011In the meat industry, the manipulation of fat deposition in cattle is of pivotal importance to improve production efficiency, carcass composition and ultimately meat quality. There is an increasing interest in the identification of key factors and molecular mechanisms responsible for the development of specific fat depots. This study aimed at elucidating the influence of breed and diet on adipose tissue membrane permeability and fluidity and their interplay on fat deposition in bovines. Two Portuguese autochthonous breeds, Alentejana and Barrosã, recognized as late- and early-maturing breeds, respectively, were chosen to examine the effects of breed and diet on fat deposition and on adipose membrane composition and permeability. Twenty-four male bovines from these breeds were fed on silage-based or concentrate-based diets for 11 months. Animals were slaughtered to determine their live slaughter and hot carcass weights, as well as weights of subcutaneous and visceral adipose depots. Mesenteric fat depots were excised and used to isolate adipocyte membrane vesicles where cholesterol content, fatty acid profile as well as permeability and fluidity were determined. Total accumulation of neither subcutaneous nor visceral fat was influenced by breed. In contrast, mesenteric and omental fat depots weights were higher in concentrate-fed bulls relative to silage-fed animals. Membrane fluidity and permeability to water and glycerol in mesenteric adipose tissue were found to be independent of breed and diet. Moreover, the deposition of cholesterol and unsaturated fatty acids, which may influence membrane properties, were unchanged among experimental groups. Adipose membrane lipids from the mesenteric fat depot of ruminants were rich in saturated fatty acids, and unaffected by polyunsaturated fatty acids dietary levels. Our results provide evidence against the involvement of cellular membrane permeability to glycerol on fat accumulation in mesenteric fat tissue of concentrate-fed bovines, which is consistent with the unchanged membrane lipid profile found among experimental groups.This study was supported by Fundação para a Ciência e a Tecnologia (FCT) through grant PTDC/CVT/2006/66114 and individual fellowships to Ana P. Martins (SFRH/BD/2009/65046), Ana S. H. Costa (SFRH/BD/2009/61068) and Susana V. Martins (SFRH/BPD/2009/63019). Paula A. Lopes is a researcher from the program ‘‘Ciência 2008’’ from FC
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