847 resultados para Step-stress accelerated life test


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Com objetivo de avaliar qualidade de vida entre mulheres portadoras de HIV/AIDS, aplicou-se o HIV/AIDS ­ Quality of Life test (HAT-QoL), instrumento específico para indivíduos infectados pelo HIV. Compõe-se de 42 questões e divide-se em nove domínios com questões sobre diversos aspectos de vida dos portadores. A escala foi submetida à tradução reversa e pré-teste. Sua forma definitiva foi aplicada entre 73 mulheres com HIV/AIDS. Os resultados, após análise estatística, indicaram que os domínios mais comprometidos foram: Preocupações financeiras, Preocupação com sigilo sobre a infecção, Atividades sexuais e Preocupações com a saúde. Esses resultados foram atribuídos ao fato das mulheres apresentarem, além da infecção, uma situação sócio-econômica precária que, provavelmente, também interferiu negativamente em sua qualidade de vida. Concluímos que a escala HAT-QoL foi adequada para a população de mulheres portadoras de HIV deste estudo, apesar de ser originária de uma cultura diferente da brasileira, já que sua aplicação produziu resultados semelhantes aos da literatura internacional.

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Dentro de um programa de controle de qualidade, a avaliação do vigor de sementes é fundamental e necessária para o sucesso da produção. Este trabalho teve como objetivo avaliar a eficiência de diferentes testes de vigor na avaliação da qualidade fisiológica de sementes de triticale (X. triticosecale Wittmack), buscando a diferenciação de lotes. Cinco lotes da cultivar 'IPR 111' foram submetidos ao teste de germinação, primeira contagem, teste de frio, condutividade elétrica (50 sementes 50mL-1 de água; 25°C 24h-1), lixiviação de potássio (50 sementes 75mL-1 de água; 25°C 3h-1), envelhecimento acelerado (43°C 48h-1) e teor de água. O teste de condutividade elétrica e lixiviação de potássio são eficientes na diferenciação do vigor de lotes de sementes de triticale.

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Horizontal transfer ( HT), defined as the transfer of genetic material between species, is considered to be an essential step in the 'life cycle' of transposable elements. We present a broad overview of suspected cases of HT of transposable elements in Drosophila. Hundred-one putative events of HT have been proposed in Drosophila for 21 different elements (5.0% refer to non-long terminal repeat (LTR) retrotransposons, 42.6% to LTR retrotransposons and 52.4% to DNA transposons). We discuss the methods used to infer HT, their limits and the putative vectors of transposable elements. We outline all the alternative hypotheses and ask how we can be almost certain that phylogenetic inconsistencies are due to HT.

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The objective of this research was to study the accelerated aging test to evaluate the okra vigor seed. Were used four okra seed lots cv. "Santa Cruz". The initial seed lot quality was evaluate by the moisture content, germination, first germination count, speed of germination index and seedling emergence. The experiment was carried out in two phases: the first one the seeds were submitted to the accelerate aging with and without NaCl salt solution aging periods of 48, 72, 96 and 120 hours, at 41 and 45(0) C temperature. The second phase the best procedures as for as accelerated aging and temperatures were repeated. The period of 72h and 41 C with and without NaCl saturated solution was the most adequate for the lot classification in distint vigor levels.

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Standard Test Methods (e.g. ASTM, DIN) for materials characterization in general, and for fatigue in particular, do not contemplate specimens with complex geometries, as well as the combination of axial and in-plane bending loads in their methodologies. The present study refers to some patents and the new configuration or configurations of specimens (non-standardized by the status quo of test methods) and a device developed to induce axial and bending combined forces resultants from axial loads applied by any one test equipment (dynamic or monotonic) which possesses such limitation, towards obtaining more realistic results on the fatigue behavior, or even basic mechanical properties, from geometrically complex structures. Motivated by a specific and geometrically complex aeronautic structure (motor-cradle), non-standardized welded tubular specimens made from AISI 4130 steel were fatigue-tested at room temperature, by using a constant amplitude sinusoidal load of 20 Hz frequency, load ratio R = 0.1 with and without the above referred auxiliary fatigue apparatus. The results showed the fatigue apparatus was efficient for introducing higher stress concentration factor at the welded specimen joints, consequently reducing the fatigue strength when compared to other conditions. From the obtained results it is possible to infer that with small modifications the proposed apparatus will be capable to test a great variety of specimen configurations such as: squared tubes and plates with welded or melted junctions, as well as other materials such as aluminum, titanium, composites, polymeric, plastics, etc. © 2009 Bentham Science Publishers Ltd.

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The objective of this work was to evaluate the efficiency of different vigor tests to assess S. commersoniana seeds physiological quality during storage. Therefore, seeds were stored in cloth bags, plastic bags and glass containers for 531 days, both at room temperature and in a cold chamber. Periodically samples were taken and the following tests were conducted: standard germination, germination speed index, first count after germination, seedlings fresh and dry matter, electrical conductivity (imbibitions for 2 and 24 hours) and accelerated aging, in order to monitoring the seeds physiologic quality. Data were submitted to polynomial regression analysis, for each of the combination of packaging/storage condition. The results obtained led to the following considerations: a) the speed germination index and the accelerated aging test permitted a good evaluation of the seed-lots quality; b) the first count of germination did not allow any prediction about seed lots vigor; c) seedling fresh and dry matter did not discriminate among seed lots; d) electrical conductivity test after 2 h imbibitions was not adequate to evaluate the seed lots vigor and e) the electric conductivity test with 24 h imbibitions was more adequate to differentiate among seed lots, but with little efficiency to discriminate among seed lots with intermediate vigor or with low quality differences.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pain is a subjective condition and, thus, difficult to measure. The best tools to assess pain are the pain evaluation questionnaires, which provide either diagnostic, pain evolution or pain intensity information. To provide information which could help differentiate between nociceptive pain and neuropathic pain is one of the most important functions of these questionnaires. The questionnaires can measure pain intensity, quality of life, or sleep quality. Quality of life and sleep are two really important characteristics to assess the pain impact on patients' life. Pain intensity assessing questionnaires combine physical evaluations with questions, providing information either from the patient sensations or clinical assessment of pain manifestations as well as the underlying biological mechanisms (such as hyperalgesia or allodynia). For example, the Pain Detect questionnaire has two parts: the patient form (intuitive, with pictures and easy understandable) and the physician form. Thus, in this questionnaire, subjective information is provided by the patient and the objective one is provided by the physician. Other pain intensity questionnaires are NPSI, DN4, LANSS or StEP. Quality of life questionnaires are versatile (can be used in different pathologies). These questionnaires include functional self-evaluation questions, and other ones associated to physical and mental health. Two of such quality of life questionnaires are SF-36 and NHP. Sleep evaluation questionnaires include quantitative features such as the number of sleep interruptions, sleep latency or sleep duration as well as qualitative characteristics such as rest sensation, mood and dreams. One of the most used sleep evaluation questionnaires is PSQI, which includes patient questions and bed-partner questions, providing information from two points of view. Copyright 2009 Prous Science, S.A.U. or its licensors. All rights reserved.

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The aim of this study was to evaluate the effect of brushing with a Colgate 360° or Oral B Indicator 35 toothbrush on the shear bond strength of orthodontic brackets bonded to extracted human teeth. The bristle wear and bristle tip morphology were also examined after simulated tooth-brushing. Orthodontic brackets (Roth-P/1 st and 2 nd pre-molar S/D- Slot 0.18) were bonded (Transbond XT ®) to the smoothest surface of each of 45 extracted human molar and premolar teeth. Test specimens were randomly divided into three groups: Group 1, control group with no brushing; Group 2, brushing with the Oral B Indicator 35; Group 3, brushing with the Colgate 360°. Samples were adapted to a machine that simulated tooth-brushing. The bond strength of each bracket to each tooth was assessed with a mechanical testing machine. The bristle wear and bristle tip morphology indices were also assessed. Statistically significant differences were defined for p ≤ 0.05. The average bond strengths (range: 90.18-90.89 kgf/cm 2) did not differ among the three groups. The Colgate 360° showed less bristle wear and a better bristle tip morphology than the Oral B Indicator 35 toothbrush. However, use of either toothbrush did not decrease the bond strength of the orthodontic brackets. Therefore, patients undergoing orthodontic therapy can safely use either toothbrush.

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Investigation of the effectiveness of surface treatments that promote a strong bond strength of resin cements to metals can contribute significantly to the longevity of metal-ceramic restorations. This study evaluated the effect of surface treatments on the shear bond strength (SBS) of a resin cement to commercially pure titanium (CP Ti). Ninety cast CP Ti discs were divided into 3 groups (n=30), which received one of the following airborne-particle abrasion conditions: (1) 50 μm Al2O3 particles; (2) 30 μm silica-modified Al2O3 particles (Cojet Sand); (3) 110 μm silica-modified Al2O3 particles (Rocatec). For each airborne-particle abrasion condition, the following post-airborne-particle abrasion treatments were used (n=10): (1) none; (2) adhesive Adper Single Bond 2; (3) silane RelyX Ceramic Primer. RelyX ARC resin cement was bonded to CP Ti surfaces. All specimens were thermally cycled before being tested in shear mode. Failure mode was determined. The best association was Rocatec plus silane. All groups showed 100% adhesive failure. There were combinations that promote higher SBS than the protocol recommended by the manufacturer of RelyX ARC.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Temporomandibular disorders is a collective term used to describe a number of related disorders involving the temporomandibular joints, masticatory muscles and occlusion with common symptoms such as pain, restricted movement, muscle tenderness and intermittent joint sounds. The multifactorial TMD etiology is related to emotional tension, occlusal interferences, tooth loss, postural deviation, masticatory muscular dysfunction, internal and external changes in TMJ structure and the various associations of these factors. The aim of this study was to evaluate the prevalence of the relationship between signs of psychological distress and temporomandibular disorder in university students. A total 150 volunteers participated in this study. They attended different courses in the field of human science at one public university and four private universities. TMD was assessed by the Research Diagnostic Criteria (RDC) questionnaire. Anxiety was measured by means of a self-evaluative questionnaire, Spielberger's Trait-State anxiety inventory, to evaluate students'state and trait anxiety. The results of the two questionnaires were compared to determine the relationship between anxiety levels and severity degrees of chronic TMD pain by means of the chi-square test. The significance level was set at 5%. The statistical analysis showed that the TMD degree has a positive association with state-anxiety (p = 0.008; p < 0.05) and negative with trait-anxiety (p = 0.619; p < 0.05). Moreover a high TMD rate was observed among the students (40%). This study concluded that there is a positive association between TMD and anxiety.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

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Pós-graduação em Ciências Cartográficas - FCT