976 resultados para Carga hidráulica superficial


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Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

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The disadvantages generated by the acid etching of the dentin, such as an increase in its permeability, in the surface moisture and in the potential to denature the external dentinal collagen, the formation of a fragility zone and the citotoxicity of the adhesive monomers; which are all aggravated by the depth of the dentin, have stimulated new and different treatment philosophies of the dentin. The purpose of the present study, therefore, was to investigate the effects of three dentin treatments: laser irradiation, acid etching and hypermineralization, in the shear bond strength of the SMP Plus bonding system. Sixty bovine incisors were extracted and randomly selected immediatly alter the animal's death. They were kept frozen (-18°C) for no longer than 14 days. After buccal dentinal surface had been exposed, X-Rays were taken to control the dentin thickness. The specimens were separated into two groups: (1) Control, kept in distilled water at 4ºC; (2) Mineralized, kept in hypermineralized solution at 4°C for 14 days. Each group was divided into three sub-groups according to the type of dentin treatment used: group F - followed the manufacturer instructions (acid-etching + primer + bond), group AL (acid-etching + primer + bond + laser) and group LA (laser + (laser + acid-etching + primer + bond). A composite resin standard cylinder (Z100-3M) was bond to the dentinal surface and the shear bond strength performed on a Universal lnstron machine 4301, with 500 Kg load and at 0,5mm/min. speed. The analysis of variance (ANOVA) determined that the treatments influenced the shear bond strength values (p<0,05) with the following average shearing load at failure: AL (9,96 MPa), F (7,28MPa) e LA (4,87 MPa). The interaction between the two factors analyzed Group (control and mineralized) and treatment (F, AL, LA) also influenced the shear bond strength (p<0,05). The highest values were obtained...

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INTRODUÇÃO: Um dos benefícios promovidos pelo exercício físico parece ser a melhora da modulação do sistema nervoso autônomo sobre o coração. No entanto, o papel da atividade física como um fator determinante da variabilidade da frequência cardíaca (VFC) não está bem estabelecido. Desta forma, o objetivo do estudo foi verificar se há correlação entre a frequência cardíaca de repouso e a carga máxima atingida no teste de esforço físico com os índices de VFC em homens idosos. MÉTODOS: Foram estudados 18 homens idosos com idades entre 60 e 70 anos. Foram feitas as seguintes avaliações: a) teste de esforço máximo em cicloergômetro utilizando-se o protocolo de Balke para avaliação da capacidade aeróbia; b) registro da frequência cardíaca (FC) e dos intervalos R-R durante 15 minutos na condição de repouso em decúbito dorsal. Após a coleta, os dados foram analisados no domínio do tempo, calculando-se o índice RMSSD, e no domínio da frequência, calculando-se os índices de baixa frequência (BF), alta frequência (AF) e razão BF/AF. Para verificar se existe associação entre a carga máxima atingida no teste de esforço e os índices de VFC foi aplicado o teste de correlação de Pearson (p < 0,05). RESULTADOS: Características demográficas, antropométricas, fisiológicas e carga máxima atingida no teste ergométrico: idade = 63 ± 3,0 anos; IMC = 24 ± 2kg/m²; FC = 63 ± 9bpm; PAS = 123 ± 19mmHg; PAD = 83 ± 8mmHg; carga máxima = 152 ± 29 watts. Não houve correlação entre os índices de VFC com os valores de FC de repouso e carga máxima atingida no teste ergométrico (p > 0,05). CONCLUSÃO: Os índices de variabilidade da frequência cardíaca temporal e espectrais estudados não são indicadores do nível de capacidade aeróbia de homens idosos avaliados em cicloergômetro.

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In 2001, it was estimated that pesticide used worldwide exceeded 2.27 billion kilograms, over 35%, of which, were herbicides. Brazil is considered one of the leaders in the production of sugarcane and mainly ethanol as fuel. The monoculture of sugarcane requires the usage of a range of pesticides, among these, the herbicides diuron and tebuthiuron. The degradation products most studied (DCA and DCPU) are diuron's, especially for toxicological characteristics of this herbicide that is identified as carcinogen and suspected to be endocrine disruptor in mammals. After optimization of the chromatographic separation using HPLC-UV, the analytical curve was constructed in solvent and subsequently in the matrix (surface water). The extraction method contains the usage of SPE (solid phase extraction) (Strata-X, 200 mg/6 mL), applicating 1L of sample and elution with 5 mL of acetonitrile / methanol (50:50, v/v). Analysis by HPLC/UV was performed in gradient mode, acetonitrile/water (70/30-74/26 by 1 min, 74/26 - 78/22 till 3.2 min, returning to initial conditions and remaining this way until 10 min), 018 column (Phenomenex, 4.6 mm diameter, 250 mm long and 5pm particle size) and detection at 254 nm. Tests F and t were performed to verify the presence of the matrix effect. There was matrix effect to all analytes, ranging from -33% (DCA) and 38% (tebuthiuron). Thereby the method was optimized and validated for analysis of diuron, tebuthiuron, and DCPU DCA in surface water using HPLC/UV. The data obtained show that in order to assure the analytical reliability desired the use of the analytical curves in the matrix for the quantification of these analytes in water is required.

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Pós-graduação em Engenharia Mecânica - FEB

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The response of bone metabolism is directly related to hormonal factors and mechanical stimuli that the bone is exposed. The ultrasonic energy on bone healing have been shown to be crucial for the stimulation and improvement in quality of newly formed tissue. The aim of this study was to analyze the action of low intensity ultrasound on bone healing of tibial osteotomy in rats subjected to tail suspension, through histological analysis and histomorphometry. Eighteen Rattus norvegicus albinos, Wistar, adults were divided into three groups, arranged as follows: G1 (n = 6), who remained free for a period of 15 days, G2 (n = 5), suspended by the tail for a period of 15 days and G3 (n = 7), suspended by the tail for a period of 36 days. In all three groups, both tibias were subjected to mono-cortical bone injury 4X2 mm in the medial region of the diaphysis, and the left limb was used as control and the right limb undergoing treatment with ultrasound (U.S.). The right tibia was treated with pulsed ultrasound at a frequency of 1.5 MHz, duty cycle 1:4, 30mW/cm2, for 12 sessions of 20 minutes each. Samples of tibia were subjected to histological analysis, blindly, with light microscopy and histomorphometric analysis by specific software Image-Pro 6.1. The average percentage of new bone formation were subjected to analysis of variance in subdivided parcels and multiple comparison test "Student-Newman-Keuls (SNK), with a significance level of 5%. The average values and standard deviations of the percentage of newly formed bone for the groups showed the least amount of bone repair G1t (13.62% ± 4.88%) - G1c (8.68% ± 4.16%) compared G2t groups (27.17% ± 11.36%) - G2c (10.10% ± 7.90%) and G3t (23.19% ± 5.61%) - G3c (15.74% ± 7 08%). However, the mean values and standard deviations of the percentage of newly formed bone repair in the tibia treated G2t and G3t were significantly higher when compared to the repair of tibia in the control group (G2c and G3c). Consequently, we conclude that ultrasound has helped to accelerate bone repair in both the presence and absence of cargo.

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Low-intensity laser has been used as a physical agent in various fields of medical sciences such as bone and tissue repair. Meanwhile little is known about its effects in adverse conditions such as abolition of load and osteopenic. With the assumption that the laser Ga-Al-As accelerates the process of bone consolidation, goal of this study was to evaluate bone mineral density (BMD) in incomplete transverse osteotomies of tibia in adult rats, treated with low power laser therapy in three different groups: G1 (n = 10), reference 15 days; G2 (n=10), suspended by the tail and, accordingly, treated with laser for 12 days; G3 (n = 10), suspended by the tail by 36 days and that after 21 days, there was laser treatment for 12 days. The right tibia treated with laser and left served as control. The laser was used to Ga-Al-As, DMC - Flash Lase® III, with wavelength 830nm, 100 mW, 4J, 140 J / cm ², 40s of application in 12 sessions. It was used densitometer-Lunar DPX®, with computer program for "small animals", and the analysis of BMD was made in the bone throughout the region and the osteotomy. The results showed no efficacy of laser therapy in the process of bone repair, both in animals of group 1, as in group 2 and 3. It follows that either the low-power laser was not an effective performance or the effects of laser therapy is not only manifested at the site of irradiation as well as the systemic level.

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Muscle activity has been studied indirectly through analyses of temperature variation in skin surface temperature on the masticatory muscles. These procedure may be an important tool for clinical evaluation and assessment of the evolution of temporomandibular disorders, as well as monitoring the adopted protocol. Thus, its utilization for identified pathological alterations on blood circulation and/or on metabolic activity in subcutaneous tissues, such as the masticatory muscles, is justified. The aim of this study was to investigate the effect of occlusal splints’ thickness on the variation of surface temperature of the anterior temporal and masseter muscles during rest and clenching. It were analyzed 20 symptomatic subjects (10 males and 10 females) selected through the Research Diagnostic Criteria (RDC) questionnaire. Temperature expressed in degrees Celsius (ºC) was measured on the surface of both muscles measured with the aid of a digital thermometer with an infrared radiation reading system. The surface temperature of the anterior temporal and masseter muscles presented significant reduction during teeth clenching in relation to the mandibular rest position. However, there were no significant differences between conditions with and without occlusal splint or between the different thicknesses of splints analyzed. Masticatory muscles showed a considerable similar behavior for both sides, and no significant distinctions were observed between male and female patients.

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The physical (pH) and microbiological (psychotrofi c microorganisms and lactic bacteria) characteristics of beef outside round (m. Biceps femoris) injected (15%) with brines free of polyphosphates containing and sodium lactate or sodium lactate and sodium diacetate and liquid bovine plasma (PLL and PLO) or dehydrated bovine plasma (PDL, PDO) were evaluated along with beef cuts injected with brines free from plasma, but containing polyphosphates and bacteriostatic agents (CL and CO) and non injected beef cuts (IN), comprising seven treatments of cooked and vacuum packaged beef steaks stored under refrigeration (6ºC) during 43 days. No differences in pH were detected among raw or cooked injected treatments, although IN showed lower pH value in raw beef cuts. The addition of liquid or dehydrated bovine plasma did not affect the microbial load after whole muscles pasteurization, but increased the bacterial counts in cooked beef steaks during refrigerated storage, comparing to treatments with no plasma addition (CL and CO). The storage temperature (6ºC), usually found during commercialization of meat increased the microorganisms growth rate affecting the microbiological quality, especially when plasma was added to the brine.