Propriedades térnicas de géis e xerogéis híbridos de sílica/orgânico à base de GPTS-TEOS com diferentes concentrações de GPTS

In the present work the thermal characteristics of gels and xerogels of Silica/organic hybrids derived from different concentrations of GPTS-TEOS were investigated by thermal analysis (TG, DTA, and DSC). The preparation of gels of the Silica/organic hybrid matrix was held through the sol-gel process, consisting by the hydrolysis of alkoxides GPTS and TEOS in proportion (1:1) and (1:2) that was promoted in acidic conditions under reflux and stirring at 80oC/2h, producing the matrix in the colloidal state (sol). Gels were prepared by addition of NH4OH to the sol, promoting gelation of sol in sealed plastics containers. Part of the gels samples was analyzed by TG, DTS and DSC techniques in order to characterize water loss and degradation of the polymeric “epoxy” groups present in the structure of the silica derived from the GPTS alkoxide. Another set of samples was dried at 80oC/48h to obtain xerogels (dried gels) and analyzed by the same techniques. We obtained the characteristics temperatures of the matrix by the techniques DTA, DSC and TG, under measurements of thermal analysis until 800oC and 600oC in case of DSC. By thermal analysis (TG, DTA, and DSC) the main endothermic events (loss of water, melting, pyrolysis) and exothermic events (burning of the polymer) of the GPTS-TEOS matrix were determined

Avaliação dos efeitos do alho (Allium sativum L.) sobre o colesterol plasmático em coelhos com hipercolesterolemia induzida

The use of plants in treatments of diseases or even in the cure of them is a high difused popular tradition, and several works talk about the therapeutic and pharmacological properties of garlic in the reduction of hyperlipidaemias. The objective of the present work was to investigate the influence of garlic (Allium sativum) aqueous extract treatment on the serum cholesterol of rabbits in experimental hypercholesterolemia. The animals were divided in G1 (control group) and G2 (group with garlic treatment). The experiment was developed in 3 phases: during the 1st phase, all the animals received regular diet for evaluation of basal cholesterol; in the 2nd phase all the animals received supplemented diet until the end of the experiment, in order to develop hypercholesterolemia and in the 3rd phase, the animals of G2 received the garlic treatment. The cholesterol registered on the 1st phase was 39,94 ± 9,57mg/dL. On the 2nd phase, there was an increase on the serum cholesterol level in both groups – higher than 100mg/dL. Concerning the treatment, garlic didn’t reduce the serum cholesterol in rabbits

Propriedades de adesão e invasão de cepas de Escherichia coli isoladas de pacientes com doença inflamatória intestinal

A Doença Inflamatória Intestinal (DII) engloba um grupo de processos inflamatórios crônicos de causas não conhecidas. Duas formas clínicas da DII são reconhecidas atualmente: a Retocolite Ulcerativa (RU) e a Doença de Crohn (DC). Foram isoladas de 348 amostras, dos quais 17 foram diagnosticados com com DC, e 40 com RU. Os 41 restantes apresentavam outras patologias e compreenderam o grupo controle. Entre as amostras que apresentaram adesão positiva, 110 delas apresentaram padrão de Adesão Agregativa (AA) e 19 apresentaram padrão de Adesão Difusa (AD). A cepa, DII/013, apresentou o padrão de adesão agregativo e invisibilidade média 18 vezes superior à cepa da EIEC. Quando observada ao microscópio eletrônico, bactérias intracelulares foram detectadas na amostra. Assim, a maioria das amostras apresentaram padrão de adesão agregativo, indicando juntamente com estudos anteriores, que esse padrão teria uma possível relação com a patogenicidade da bactéria em relação a DII

Estudo das propriedades físicas em materiais vítreos do sistema 50B2O3 - 15CuO - 20Li2O - 15X (X= Na2O, K2O, RbCI e Cs2O)

The increasing demand for devices for solid state applications in many technological areas has resulted in a high demand for new materials. Among these material have the advantage of being manufactured with different chemical compositions, and may have physical properties equal to or higher than the corresponding crystalline material. The aim of this paper was to produce borate glass system 50B2O3 – 15CuO – 20Li2O – 15X (X = Na2O, K2O, RbCl e Cs2O) to analyze the influence of the atomic radius of alkali in the physical properties of this glass system. The glasses were synthesized by the process of melting and molding. The characteristic temperatures were determined by the technique of scanning calorimetry (DSC). The non-crystalline was determined by x-ray diffraction. In order to determine the molar volume a density measurement by using the Archimedes method was used. The structural characterization was carried out using the technique of infrared spectroscopy

Estudo das propriedades mecânicas do aço SAE 1312 modificado ao nióbio

The study of mechanical properties of high-alloy special steels is of great interest of the steel industry due to the great demand by companies that manufacture automotive components of high criticality, and also because of its high commercial value. However, the development of this type of alloy metals demand highly technical knowledge. Among these extremely important kinds of steel, the subject which is the interest of this study is the special steel modified by niobium. The manganese and niobium are the main alloying elements in the composition of these steels, both of them increase the stability of the austenite region, however, manganese increases the hardenability and tensile yield strength, and niobium increases the mechanical strength and promotes refining the grain. The mechanical characterization of steel SAE 1312 modified the niobium was made in order to gain a better understanding of the influence on the mechanical properties caused by aging at different temperatures and for different reductions in the drawing of gauge material. This characterization was made by means of tensile test and hardness. This material showed an increase in yield strength and hardness when gauge with large reductions during the wiredrawing, but when subjected to aging temperatures higher than 300 ° C had a slight loss of these properties

Efeito de intervenções não farmacológicas nos níveis de estresse em cuidadores de pacientes com doença de Alzheimer: uma revisão sistemática

Beside aging process comes the incidence of dementia and, among them Alzheimer's disease (AD) accounts for approximately 60% of cases. This disease is characterized as a neuropathology with unknown etiology that causes cognitive deficits and behavioral disorders. Caring for patients with AD can cause an overload, both physical and psychological, which can cause high levels of stress on the primary caregiver. It is necessary that the caregiver also receives attention and develop activities that promote health benefits, while providing moments of distraction from the task of caring. Nonpharmacological interventions may be favorable for improving health with consequent decreased on the levels of stress. The objective of this study was to conduct a systematic review of scientific papers that aimed to verify the effect of nonpharmacological interventions on stress levels in caregivers of patients with AD. To contamplate this goal was accomplished a systematic search in the following databases: Biological Abstracts, PsycINFO, PubMed/Medline, Web of Science, LILACS and SciELO. The following keywords and Boolean operators was used: “caregivers” OR “family” and “nonpharmacological interventions” OR “support groups” OR “therapies” AND “Alzheimer's disease” OR “Alzheimer's dementia” OR “Alzheimer” OR “elderly” AND “stress”. There were found 3studies that met inclusion criteria adopted for the present work, and none showed significant results for the variable stress. It is not possible to affirm, according to the studies, that nonpharmacologial interventions programs for caregivers of patients with AD are effective to influence and to control the stress. However, studies show benefits for other variables such as self-efficacy and confidence in relation to care... (Complete abstract click electronic access below)

Avaliação da influência da taxa de resfriamento posterior ao tratamento térmico nas propriedades mecânicas do aço API 5L X70

In this work a study about the mechanical properties of the API 5L X70 steel, with or without heat treating, has been made, with the intetion of assess the influence of cooling after the austenitization heat treating by air cooling (normalizing) and a rapid cooling with oil (tempering). This steel is known by high strength and ductility values and it is commonly used in the manufacture of oil pipes. The growing energy demand encouraged the study and manufacture of this material. Although this microalloyed dispense subsequent heat treatings, it was proven that its implementation is very advantageous for this type of application, improving hardness and plastic stability. It was also assessed that the faster the cooling rate is, the better will be these properties

Avaliação do efeito ambiental nas propriedades mecânicas e viscoelásticas de compósitos híbridos de titânio/fibra de carbono/resina epóxi

Hybrid composites combining metal plates and laminates with continuous fiber reinforced polymer, called fiber-metal (CHMF), have been particularly attractive for aerospace applications, due mainly to their high mechanical strength and stiffness associated with low density. These laminates (CHMF) consist of a sandwich structure consisting of layers of polymer composites and metal plates, stacked alternately. This setting allows you to combine the best mechanical performance of polymer composites reinforced with long fibers, to the high toughness of metals. Environmental effects should always be considered in the design of structural components, because these materials in applications are submitted to the effects of moisture in the atmosphere, the large cyclical variations of temperature around 82 ° C to -56 ° C, and high effort mechanical. The specimens of fibermetal composite were prepared at EMBRAER with titanium plates and laminates of carbon fiber/epoxy resin. This study aims to evaluate the effect of different environmental conditions (water immersion, hygrothermal chamber and thermal shock) of laminate hybrid titanium/carbon fiber/epoxy resin. The effects of conditioning were evaluated by interlaminar shear tests - ILSS, tensile, and vibration free

Influência do condicionamento ambiental sobre as propriedades viscoelásticas de compósitos aramida/epóxi

The increasing application of structural composites in the aerospace industry is mainly due to its low specific weight coupled with its excellent mechanical properties when in service. As a result of climatic variations that pass the aircraft is of paramount importance to study the influence of weathering on this type of material when subjected to such changes. The purpose of this work is to evaluate the mechanical behavior of specimens of kevlar fiber /epoxy matrix composites, by dynamic mechanical thermal analysis (DMA) and interlaminar shear strength tests (ILSS), after passing through three environmental conditioning: saline fog, hygrothermal and ultraviolet radiation. From the results, we concluded that the laminate was molded supplied homogeneously, not presenting problems such as porosity, delaminations or cracks inside. After a period of 625 hours of exposure to hygrothermal conditioning, we observed a 1,2% maximum of absorption of moisture. Samples subjected to the conditioning by UV irradiation (600 hours) and salt spray showed a reduction of about 24,30% and 32,30%, respectively, on the shear strength (ILSS). In DMA analysis is not observed significant changes on the glass transition temperature. However, when considering the storage modulus of the samples conditioned by UV radiation (1200 hours), salt spray and hygrothermal conditioning there is an increase of 5,34% , 7,19% and 5,57% respectively

Estudos exploratórios sobre propriedades térmicas do compósito cimento-polpa celulósica(CPC)

The search for a more aware use of available raw materials has led to a need to create more sustainable products. The use of natural fibers to reinforce cement, for instance, has been widely studied in the past decades because of the possibility that they can improve material properties such as thermal resistance and to compression, besides conferring a decrease in their total weight. This present study aimed at to conduct preliminary studies on the thermal resistance of the composite cement - Cellulose Pulp, using waste from the pulp and paper industry. Through experiments, it was found that the composite manufactured using the ratio 30 % Portland cement and 70 % pulp, showed satisfactory results regarding its thermal resistance, so it could be considered as a potential thermal insulation material, for use in constructions

Hidrogéis do ácido acrílico: correlação das propriedades bioadesivas e lereação in vitro do metronidazol

Este trabalho teve por objetivo desenvolver hidrogéis do ácido acrílico e correlacionar as propriedades bioadesivas e a liberação in vitro empregando metronidazol. Para tanto, inicialmente foram preparadas dispersões dos polímeros Carbopol 974 ® e Policarbofil ® nas concentrações de 0,5%, 1,0% e 1,5%, que foram submetidas a testes para avaliação das propriedades bioadesivas, mecânicas e reológicas. As amostras com maior concentração de polímeros (Carbopol 974 ® 1,5%, e Policarbofil ® 1,0% e 1,5%,) foram as que apresentaram melhores resultados nos testes de bioadesão, e portanto selecionadas para prosseguimento dos estudos, que envolveu a incorporação de metronidazol (MTZ) na concentração de 0,5% para estudo de liberação in vitro por 12 horas. O experimento foi realizado por meio do sistema automático com célula de difusão vertical de Franz e solução tampão fosfato pH 7,4 como solução receptora. A temperatura utilizada foi 32,5 o C. Os resultados demonstraram que o tipo e a concentração do polímero influenciou diretamente na liberação do fármaco. Os melhores resultados em termos de controle de liberação foram apresentados pelo polímero Policarbofil ® na concentração de 1,5%

Simulação de contaminação de sedimentos e águas subterrâneas por gasolina e álcool: um estudo de monitoramento de variações das propriedades físico-químicas

Geophysics studies in areas impacted by petroleum derivatives describe abnormalities of both low and high electrical resistivity (the opposite of electrical conductivity), confirmed as contaminant phase by chemical analysis: this contradiction can be explained by degrading processes that naturally occur and create sub products that can change the environment conductivity. Monitoring the variation of the parameters mentioned serves as a comparative basis to the variation in geoelectrical parameters, which identified the correlation between the same contaminant parameters and the difference between their behavior studied apart, as well as its relations with the biodegradation process. The results are applied to the fuel distribution and storage sectors, leading to the diagnosis and monitoring of possible groundwater contamination scenarios, and the knowledge of the area exposure time to the contaminant, besides the better remediation alternative and impacts control. Among some conclusions, the most significant are the decrease in conductivity over time, so as the increase in Eh value in the gasoline contaminated tank, as well as the decrease in the pH value in the second tank with ethanol, which can be attributed to its degradation. Comparing the variations in both tanks, it is evident that Eh, pH and electrical conductivity do not behave temporally in a similar way, although some correlations between Eh and pH can be related.

Propriedades físico-químicas e mecânicas, potencial bioativo e caracterização da interface dentina-cimento de cimentos endodônticos experimentais à base de cimento Portland associados à radiopacificadores micro e nanoparticulados

Pós-graduação em Odontologia - FOAR

Colágeno: caracteristicas químicas e propriedades funcionais

Many types of food contain ingredients or bioactive compounds that provide health benefits. The collagen is a fibrous protein found in the connective tissue of the body, and it plays a part in the tissues resistance and elasticity. Due to their functional characteristics, this protein has been added into foods in order to achieve therapeutic effects. This paper aimed at showing how the collagen formation occurs, and the beneficial effects of this compound in the organism as well as its characteristics, properties and applications in food.

Cogumelos: compostos biativos e propriedades antioxidantes

This study presents a literature review which shows the nutritional, medicinal and antioxidant importance of mushrooms. In this research, the main antioxidant compounds of mushrooms, such as phenolic acids, flavonoids and tocopherols, as well as their mechanisms of action were described. The main in vitro methods used for evaluation of the antioxidant activity of these compounds were approached. The influences from the solvent polarity and the kind of extraction in the acquisition of the antioxidant compounds were also discussed. It was possible to conclude that mushrooms are a source of carbohydrates, proteins and minerals, thus presenting nutritional properties. The functional and medicinal properties are attributed to glucans, besides being excellent sources of natural antioxidants. Regarding the extraction process, it was noticed that the solvent polarity used in the extraction process is determinant in the obtainment of antioxidant compounds.