315 research outputs found

    Approaches in biotechnological applications of natural polymers

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    Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

    Exploring Cluster Analysis in Nelore Cattle Visual Score Attribution

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    Assessing the biotype of cattle through human visual inspection is a very common and important practice in precision cattle breeding. This paper presents the results of a correlation analysis between scores produced by humans for Nelore cattle and a variety of measurements that can be derived from images or other instruments. It also presents a study using the k-means algorithm to generate new ways of clustering a batch of cattle using the measurements that most correlate with the animal's body weight and visual scores

    Estudo sobre lubrificação em rolamentos e desenvolvimento de um tribômetro método reichert

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    O estudo se destina a abordagem das possíveis falhas em elementos de máquinas (rolamentos) fabricados em AISI 52100 e seus principais mecanismos de desgaste sendo adesão, abrasão, corrosão e fadiga. Serão apresentados os principais tipos de lubrificantes, dando ênfase nos óleos e graxas quanto a suas características físico-químicas e seus principais aditivos. Para viabilidade do estudo foi desenvolvido um dispositivo que realizou ensaios em um mesmo lubrificante de viscosidade 15W4-50 com períodos de utilização distintos sendo estes 1000, 2000 e 3000 km, desta forma foi possível medir o rompimento da película de lubrificação em função da pressão  exercida  pelo  dispositivo  e  sendo  assim  exemplificar  de  maneira  efetiva  os  efeitos danosos aos elementos de máquinas em função da má gestão da lubrificação

    Exercise inhibits the effects of smoke-induced COPD involving modulation of STAT3

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    Purpose . Evaluate the participation of STAT3 in the e ff ects of aerobic exercise (AE) in a model of smoke-induced COPD. Methods . C57Bl/6 male mice were divided into control, Exe, COPD, and COPD+Exe groups. Smoke were administered during 90 days. Treadmill aerobic training begun on day 61 until day 90. Pulmonary in fl ammation, systemic in fl ammation, the level of lung emphysema, and the airway remodeling were evaluated. Analysis of integral and phosphorylated expression of STAT3 by airway epithelial cells, peribronchial leukocytes, and parenchymal leukocytes was performed. Results . AE inhibited smoke-induced accumulation of total cells ( p <0 001 ), lymphocytes ( p <0 001 ), and neutrophils ( p <0 001 ) in BAL, as well as BAL levels of IL- 1 β ( p <0 001 ), CXCL1 ( p <0 001 ), IL-17 ( p <0 001 ), and TNF- α ( p <0 05 ), while increased the levels of IL-10 ( p <0 001 ). AE also inhibited smoke-induced increases in total leukocytes ( p <0 001 ), neutrophils ( p <0 05 ), lymphocytes ( p <0 001 ), and monocytes ( p <0 01 ) in blood, as well as serum levels of IL-1 β ( p <0 01 ), CXCL1 ( p <0 01 ), IL-17 ( p <0 05 ), and TNF- α ( p <0 01 ), while increased the levels of IL-10 ( p <0 001 ). AE reduced smoke-induced emphysema ( p <0 001 ) and collagen fi ber accumulation in the airways ( p <0 001 ). AE reduced smoke-induced STAT3 and phospho-STAT3 expression in airway epithelial cells ( p <0 001 ), peribronchial leukocytes ( p <0 001 ), and parenchymal leukocytes ( p <0 001 ). Conclusions .AE reduces smoke-induced COPD phenotype involving STAT3
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