929 resultados para Fator limitante


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

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Introduction: The request of three-dimensional images (3D) of the dentomaxillofacial complex has increased. Hence, new possibilities for assessment, treatment as well as follow-up after treatment have increased their importance with the use of cone beam computed tomography (CBCT). The images in two dimensions (2D) have inherent problems that can be solved with treedimensional images assessment. Objectives: To clarify the main doubts about the operational mechanism of complementary diagnostic method; to explain the advantages and disadvantages, to discuss the effective radiation dose and possible applications in orthodontia. Conclusion: The information generated by 2D images from the CBCT does not show differences that may endanger the orthodontic planning when compared with the images of 2D conventional radiographs. The effective radiation dose received by the patient should not be considered as a limiting factor of the tomography exam request.

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Introduction: In dentistry, alveolar bone resorption is a limiting factor in the well being of individuals directly interfering in the stomatognathic system, causing problems in the context of overall health. Aiming to promote biological methods that can stimulate bone regeneration, several biomimetic strategies have been developed by the use of diverse materials possible to the bone matrix, culminating in the development of techniques that promote such repair. Objective: This work is a comparative study of the performance of films made with latex as occlusive membrane for Guided Bone Regeneration (GBR) procedure in three preparations: Latex preserved in ammonia, produced by Latex rubber clones IAN873 and PR255 polymerized immediately after collection and without use ammonia as a preservative. Methods: Sixty Wistar rats were randomly divided into 4 groups of 15 animals in which bone defects of critical size (8mm diameter) were made surgically in the skull. Group A was treated by GBR through the membrane latex preserved with ammonia, Group B received the membrane made of latex from IAN873, Group C, the membrane clone PR255 and group D was not treated by GBR. After a period of 7, 15 and 50 days, 5 animals from each group were euthanized, and specimens containing bone defect collected for microscopic examination (descriptive histology and histomorphometry). Results: The results showed that after 50 days there was bone formation in higher proportions in group D (p <0.05, ANOVA followed by Tukey), suggesting that further experiments should be conducted to conclude about the presence of ammonia and the influence of kind of rubber. Conclusion: GOR is a procedure proven effective in the treatment of bone defects. Therefore, further experiments should be conducted to reach a conclusion regarding the presence of ammonia in the latex composition for the manufacture of membranes, as well as the difference induced by the species of rubber.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A cardiomiopatia hipertrófica (CMH) é uma doença geneticamente determinada, caracterizada por hipertrofia ventricular primária, com prevalência estimada de 0.2% na população geral. Qualquer portador tem 50% de chance de transmitir esta doença para seus filhos, o que torna cada vez mais relevante a importância do estudo genético dos indivíduos acometidos e de seus familiares. Já foram descritas diversas mutações genéticas causadoras de CMH, a maioria em genes que codificam proteínas do sarcômero, e algumas mutações mais raras em genes não sarcoméricos. O objetivo desse estudo é sequenciar as regiões exônicas de genes candidatos, incluindo os principais envolvidos na hipertrofia miocárdica, utilizando o sequenciamento de nova geração (Generation Sequencing); testar a aplicabilidade e viabilidade deste sistema para identificar mutações já confirmadas e propor as prováveis novas mutações causadoras de CMH. Métodos e resultados: 66 pacientes não aparentados portadores de CMH foram estudados e submetidos à coleta de sangue para obtenção do DNA para analisar as regiões exômicas de 82 genes candidatos, utilizando a plataforma MiSeq (Illumina). Identificou-se 99 mutações provavelmente patogênicas em 54 pacientes incluídos no estudo (81,8%) relacionadas ou não a CMH, e distribuídas em 42 genes diferentes. Destas mutações 27 já haviam sido publicadas, sendo que 17 delas descritas como causadoras de CMH. Em 28 pacientes (42,4%) identificou-se mutação nos três principais genes sarcoméricos relacionados à CMH (MYH7, MYBPC3, TNNT2). Encontrou-se também um grande número de variantes não sonôminas de efeito clínico incerto e algumas mutações relacionadas a outras enfermidades. Conclusão: a análise da sequencia dos exônos de genes candidatos, demonstrou ser uma técnica promissora para o diagnóstico genético de CMH de forma mais rápida e sensível. A quantidade de dados gerados é o um fator limitante até o momento, principalmente em doenças geneticamente complexas com envolvimento de diversos genes e com sistema de bioinformática limitado.

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A beta-alumina de sódio é uma cerâmica condutora de íons Na+ utilizada como eletrólito sólido em baterias de sódio para armazenamento de energias intermitentes como energia solar e eólica. Devido ao alto teor de sódio, esse material é instável a altas temperaturas, podendo sofrer variações de composição durante a etapa de sinterização convencional que utiliza altas temperaturas por longos períodos de tempo. A sinterização flash é uma técnica de sinterização ativada por corrente elétrica que proporciona a densificação de compactos cerâmicos em poucos segundos, a temperaturas notavelmente mais baixas que as convencionais. Uma vez obrigatória a passagem de corrente elétrica através da amostra, a sinterização flash de qualquer material condutor parece bastante razoável. Não obstante, até o presente momento a maioria dos trabalhos publicados sobre o assunto aborda apenas condutores de vacância de oxigênio ou semicondutores, materiais compatíveis com eletrodos de platina (Pt). Nesse trabalho a sinterização flash de um condutor catiônico foi estudada utilizando-se a beta-alumina como material modelo. A beta-alumina foi sintetizada pelo método dos precursores poliméricos, caracterizada e então submetida à sinterização flash. O material de eletrodo padrão (platina) provou ser um eletrodo bloqueador em contato com a beta-alumina. O sucesso da sinterização flash foi determinado pela troca do material de eletrodo por prata (Ag), o que possibilitou uma reação eletroquímica reversível nas interfaces eletrodo-cerâmica e possibilitou a obtenção de um material densificado com morfologia e composição química homogêneas. Devido à metaestabilidade da beta-alumina, a atmosfera dos experimentos precisou ser alterada para manter a integridade desse material rico em um metal alcalino (Na+). A sinterização flash de um condutor catiônico é apresentada pela primeira vez na literatura e ressalta a importância da reação de eletrodo, que é um fator limitante para o sucesso da sinterização flash e precisa ser estudada e adaptada para cada tipo de material.

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OBJETIVO: O presente estudo teve como objetivo avaliar e comparar o efeito da cinesioterapia na qualidade de vida, função sexual e sintomas climatéricos em mulheres climatéricas com e sem fibromialgia. MÉTODOS: Participaram do estudo 90 mulheres na fase do climatério, as quais foram divididas em dois grupos: grupo fibromialgia (47) e grupo controle (43). Todas as pacientes foram avaliadas com relação às seguintes variáveis pré e pós-intervenção: qualidade de vida (Utian Quality of Life - UQOL), função sexual (questionário do Quociente sexual/versão feminina - QS-F) e intensidade dos sintomas climatéricos (Índice Menopausal de Blatt-Kupperman - IMBK). Ambos grupos foram submetidos a programa de cinesioterapia composto de 20 sessões consecutivas, realizada duas vezes por semana com técnicas para percepção, contração voluntária, dissociação e automatização do assoalho pélvico, mobilização de pelve e treino respiratório. Análise estatística foi realizada por meio dos testes t-Student pareado, análise de variância de delineamento misto e Kappa de Cohen’s, adotando-se nível de significância de 5%. RESULTADOS: Em relação à qualidade de vida, foi observada melhora estatisticamente significante no período pós-intervenção em ambos os grupos para todos os domínios avaliados. Entretanto, na análise intergrupo foi evidenciado diferença estatisticamente significante nos domínios emocional (p=0,01), saúde (0,03) e sexual (p=0,001) com ganhos mais expressivos para o grupo controle. Quanto à função sexual, foi verificada elevação significativa dos escores em ambos os grupos, após a intervenção; na análise intergrupo as mulheres com fibromialgia apresentaram escores inferiores ao grupo controle (p<0,001). Em relação aos sintomas climatéricos não houve diferença estatisticamente significante na analise intergrupo pós-intervenção (p=0,73), entretanto, ambos os grupos apresentaram redução significativa da sintomatologia após a intervenção (p<0,001). CONCLUSÕES: A cinesioterapia do assoalho pélvico exerce efeito benéfico sobre os domínios da qualidade de vida, função sexual e sintomatologia climatérica em mulheres com e sem fibromialgia na fase do climatério, entretanto a fibromialgia parece ser fator limitante para melhores resultados em alguns aspectos avaliados.

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Unplanned pregnancy is experienced by millions of women worldwide. Such fact increases the risk of abortion-related morbimortality, which represents a serious public health problem. This study aims to evaluate the advances and challenges of the implementation of Humanized Abortion Care at the Maternity-School in Natal, state of Rio Grande do Norte. The research was evaluative, was preceded by an Evaluative Study, and resulted in a Case Study. The intentional sample totaled 102 subjects (60 users, 39 professionals and 3 managers). The collection techniques included documental analysis, semi-structured interview and observation with a field diary. The documental analysis was descriptive, while the Content Analysis by Bardin was used for semi-structured interviews and field diary. The Evaluative Study observed that Humanized Abortion Care is an evaluative program with preparation and pact of the logical model, of the matrix of indicators and evaluative questions. The Case Study showed that users were satisfied with the problem-solving capacity and access to the service; however, is also showed that they pointed out inadequacy in terms of environment, qualified hearing and reproductive planning. Professionals reported that the inefficiency of service consists of infrastructure and environment, which are considered inefficient and inadequate to humanized care, especially regarding patient accommodation, the lack of hospital beds, the reduced number of rooms in the surgical center and the lack of laboratory inside the maternity. Moreover, reproductive planning does not consist of an institutionalized practice in the service, and integrality with other services or partnership with the community is not in place. The Maternity Board emphasizes that the excessive demand of patients is one of the reasons that hinders the appropriate implementation of the technical standard. We then conclude that although satisfied regarding problem-solving capacity in terms of service and ease of access, there is room for improvement in qualified hearing systems, in the creation of a system to promote team work, implementation of ombudsman and satisfaction surveys. The right of shared choice did not prevail among users and health professionals with regard to the option of uterine evacuation procedure. Environment was the most mentioned category as that requiring more changes, seeing as a limited factor for the development of humanized and welcoming practices. Health professionals do not establish a periodic routine of planning practices, and such practices are not aligned with the Technical Standard. Incorporation of guidelines and availability of a plurality of methods and possibilities of choices for family planning are required. There is no institutionalization of reference and counter-reference, or partnerships with the community, which makes integrality of care not viable. The Standard needs to be included in the action plans of managers as one of the priorities in the construction of care strategies for women's health, in order to enable, allied to other initiatives, the real integration among safe conduct service, primary care network and social organizations. As a result, respect for human rights and adequate humanized care, as a way of attention and prevention of abortion, can be secured.

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Advanced age may become a limiting factor for the maintenance of rhythms in organisms, reducing the capacity of generation and synchronization of biological rhythms. In this study, the influence of aging on the expression of endogenous periodicity and synchronization (photic and social) of the circadian activity rhythm (CAR) was evaluated in a diurnal primate, the marmoset (Callithrix jacchus). This study had two approaches: one with longitudinal design, performed with a male marmoset in two different phases: adult (three years) and older (9 y.o.) (study 1) and the second, a transversal approach, with 6 old (♂: 9.7 ± 2.0 y.o.) and 11 adults animals (♂: 4.2 ± 0.8 y.o.) (study 2). The evaluation of the photic synchronization involved two conditions in LD (natural and artificial illuminations). In study 1, the animal was subjected to the following stages: LD (12:12 ~ 350: ~ 2 lx), LL (~ 350 lx) and LD resynchronization. In the second study, the animals were initially evaluated in natural LD, and then the same sequence stages of study 1. During the LL stage in study 2, the vocalizations of conspecifics kept in natural LD on the outside of the colony were considered temporal cue to the social synchronization. The record of the activity was performed automatically at intervals of five minutes through infrared sensor and actimeters, in studies 1 and 2, respectively. In general, the aged showed a more fragmented activity pattern (> IV < H and > PSD, ANOVA, p < 0.05), lower levels of activity (ANOVA, p < 0.05) and shorter duration of active phase (ANOVA, p < 0.05) in LD conditions, when compared to adults. In natural LD, the aged presented phase delay pronounced for onset and offset of active phase (ANOVA, p < 0.05), while the adults had the active phase more adjusted to light phase. Under artificial LD, there was phase advance and greater adjustment of onset and offset of activity in relation to the LD in the aged (ANOVA, p < 0.05). In LL, there was a positive correlation between age and the endogenous period () in the first 20 days (Spearman correlation, p < 0.05), with prolonged  held in two aged animals. In this condition, most adults showed free-running period of the circadian activity rhythm with  < 24 h for the first 30 days and later on relative coordination mediated by auditory cues. In study 2, the cross-correlation analysis between the activity profiles of the animals in LL with control animals kept under natural LD, found that there was less social synchronization in the aged. With the resubmission to the LD, the resynchronization rate was slower in the aged (t-test; p < 0.05) and in just one aged animal there was a loss of resynchronization capability. According to the data set, it is suggested that the aging in marmosets may be related to: 1) lower amplitude and greater fragmentation of the activity, accompanied to phase delay with extension of period, caused by changes in a photic input, in the generation and behavioral expression of the CAR; 2) lower capacity of the circadian activity rhythm to photic synchronization, that can become more robust in artificial lighting conditions, possibly due to the higher light intensities at the beginning of the active phase due to the abrupt transitions between the light and dark phases; and 3) smaller capacity of non-photic synchronization for auditory cues from conspecifics, possibly due to reducing sensory inputs and responsiveness of the circadian oscillators to auditory cues, what can make the aged marmoset most vulnerable, as these social cues may act as an important supporting factor for the photic synchronization.

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Advanced age may become a limiting factor for the maintenance of rhythms in organisms, reducing the capacity of generation and synchronization of biological rhythms. In this study, the influence of aging on the expression of endogenous periodicity and synchronization (photic and social) of the circadian activity rhythm (CAR) was evaluated in a diurnal primate, the marmoset (Callithrix jacchus). This study had two approaches: one with longitudinal design, performed with a male marmoset in two different phases: adult (three years) and older (9 y.o.) (study 1) and the second, a transversal approach, with 6 old (♂: 9.7 ± 2.0 y.o.) and 11 adults animals (♂: 4.2 ± 0.8 y.o.) (study 2). The evaluation of the photic synchronization involved two conditions in LD (natural and artificial illuminations). In study 1, the animal was subjected to the following stages: LD (12:12 ~ 350: ~ 2 lx), LL (~ 350 lx) and LD resynchronization. In the second study, the animals were initially evaluated in natural LD, and then the same sequence stages of study 1. During the LL stage in study 2, the vocalizations of conspecifics kept in natural LD on the outside of the colony were considered temporal cue to the social synchronization. The record of the activity was performed automatically at intervals of five minutes through infrared sensor and actimeters, in studies 1 and 2, respectively. In general, the aged showed a more fragmented activity pattern (> IV < H and > PSD, ANOVA, p < 0.05), lower levels of activity (ANOVA, p < 0.05) and shorter duration of active phase (ANOVA, p < 0.05) in LD conditions, when compared to adults. In natural LD, the aged presented phase delay pronounced for onset and offset of active phase (ANOVA, p < 0.05), while the adults had the active phase more adjusted to light phase. Under artificial LD, there was phase advance and greater adjustment of onset and offset of activity in relation to the LD in the aged (ANOVA, p < 0.05). In LL, there was a positive correlation between age and the endogenous period () in the first 20 days (Spearman correlation, p < 0.05), with prolonged  held in two aged animals. In this condition, most adults showed free-running period of the circadian activity rhythm with  < 24 h for the first 30 days and later on relative coordination mediated by auditory cues. In study 2, the cross-correlation analysis between the activity profiles of the animals in LL with control animals kept under natural LD, found that there was less social synchronization in the aged. With the resubmission to the LD, the resynchronization rate was slower in the aged (t-test; p < 0.05) and in just one aged animal there was a loss of resynchronization capability. According to the data set, it is suggested that the aging in marmosets may be related to: 1) lower amplitude and greater fragmentation of the activity, accompanied to phase delay with extension of period, caused by changes in a photic input, in the generation and behavioral expression of the CAR; 2) lower capacity of the circadian activity rhythm to photic synchronization, that can become more robust in artificial lighting conditions, possibly due to the higher light intensities at the beginning of the active phase due to the abrupt transitions between the light and dark phases; and 3) smaller capacity of non-photic synchronization for auditory cues from conspecifics, possibly due to reducing sensory inputs and responsiveness of the circadian oscillators to auditory cues, what can make the aged marmoset most vulnerable, as these social cues may act as an important supporting factor for the photic synchronization.

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The growing demand for large-scale virtualization environments, such as the ones used in cloud computing, has led to a need for efficient management of computing resources. RAM memory is the one of the most required resources in these environments, and is usually the main factor limiting the number of virtual machines that can run on the physical host. Recently, hypervisors have brought mechanisms for transparent memory sharing between virtual machines in order to reduce the total demand for system memory. These mechanisms “merge” similar pages detected in multiple virtual machines into the same physical memory, using a copy-on-write mechanism in a manner that is transparent to the guest systems. The objective of this study is to present an overview of these mechanisms and also evaluate their performance and effectiveness. The results of two popular hypervisors (VMware and KVM) using different guest operating systems (Linux and Windows) and different workloads (synthetic and real) are presented herein. The results show significant performance differences between hypervisors according to the guest system workloads and execution time.

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Introdução: A disponibilidade de córneas para transplante continua a ser um fator limitante na resposta terapêutica a muitos doentes com patologia de córnea. A operacionalização do programa de colheita e transplante de córneas no Hospital Prof. Doutor Fernando Fonseca, EPE (HFF) teve início em 2012 e desde então tem sido preocupação do núcleo de Coordenação Hospitalar de Doação (NCHD) a otimização do número de colheitas respeitando os padrões de qualidade definidos pela legislação. Metodologia: Os autores apresentam uma análise retrospetiva de todos os óbitos ocorridos no HFF no ano de 2014, aplicando os critérios de seleção demográficos e clínicos bem como as limitações operacionais próprias do hospital, de modo a verificar a eficiência do processo de colheita de córneas em coração parado. Resultados: Dos 1970 óbitos do HFF em 2014, 651 (33%) cumpriam o critério idade e 66 doentes foram elegíveis tendo em conta as contra-indicações clínicas e as limitações operacionais do HFF. Destes, 32 foram efectivados como colheitas. Das contra-indicações clínicas a neoplasia de órgão sólido (n=428), serologias positivas (n= 196),doença neurodegenerativa (n=132) e sepsis (n=117) foram as mais prevalentes considerando os óbitos entre os 12 e os 80 anos. Conclusões: Conclui-se que existe uma margem importante de melhoria no processo de referenciação e selecção de dadores. Um eventual ajuste nos critérios clínicos de inclusão, respeitando as guidelines internacionais poderiam possibilitar um significativo incremento da quantidade de córneas elegíveis para colheita.

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A fixação biológica de dióxido de carbono por microalgas é considerada a melhor forma de fixar CO2. Dentre os microrganismos utilizados destaca-se Spirulina platensis devido às suas altas taxas de fixação de CO2 e variedade de aplicações da biomassa gerada. A aplicação de modelos e simulações pode auxiliar na previsão de custos e na escolha das condições ideais de cultivo. Este trabalho teve como objetivo etsabelecer um modelo cinético no qual a iluminância é o fator limitante para o crescimento da microalga Spirulina platensis. A fim de validar o modelo proposto foi utilizada a microalga S. platensis, cultivada em meio Zarrouk modificado (NaHCO3 1,0 g.L-1 ), em biorreator aberto tipo raceway de 200L, mantido a 30°C, sob iluminação natural. A concentração celular variou de 0,19 a 0,34 g.L-1 e a velocidade específica de crescimento celular obtida a partir da regressão exponencial das curvas de crescimento de cada período iluminado variou de 0,55 a 0,59 d-1 . O modelo proposto gerou dados estimados satisfatórios (r2 =0,97). De acordo com os dados obtidos 16,2% da biomassa é consumida durante o período não iluminado.