1,413 research outputs found

    Analysis of the Influence of Sparkout Time on Grinding Using Several Lubrication/Cooling Methods

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The plunge cylindrical grinding operation has been widely employed in the manufacturing process of components which require excellent surface quality achieved within small ranges of dimensional tolerance. The sparkout time has proved to be an important parameter in this operation, contributing to obtain surfaces with high geometric and dimensional precision. This parameter, which is defined as the period in which there is no wheel radial feed, allows the elimination of elastic deformations that build up as the grinding wheel is fed. Experimentation with sparkout time was applied in the plunge cylindrical grinding operation and included the Minimum Quantity Lubrication (MQL) technique, which has proved to be an environmentally correct alternative, combining a small amount of lubricating oil with an intense flow rate of compressed air. The conventional lubrication and cooling method and the method involving the nozzle proposed by Webster [10] were also used. The results showed that longer sparkout times led to a decrease in tangential forces, wheel diametrical wear and surface roughness values for the MQL method.3114751Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)UNESP Sao Paulo State University at BauruFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Dementia in a patient with Thymoma and hypogammaglobulinaemia (Good's syndrome)

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    Good's syndrome is extremely rare and refers to an acquired B and T cell immunodeficiency in thymoma patients. The authors of this article present a case report of a 75-year-old, caucasian male patient previously subjected to examinations for secondary dementia and recurrent infections, which revealed paraneoplastic syndrome arose from thymoma. He underwent thymectomy, while his immunodeficiency syndrome sustained with frequent opportunistic infections, constantly requiring intravenous immunoglobulin treatment

    Strategies to reduce sample sizes in Alzheimer’s disease primary and secondary prevention trials using longitudinal amyloid PET imaging

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    BACKGROUND: Detecting subtle-to-moderate biomarker changes such as those in amyloid PET imaging becomes increasingly relevant in the context of primary and secondary prevention of Alzheimer's disease (AD). This work aimed to determine if and when distribution volume ratio (DVR; derived from dynamic imaging) and regional quantitative values could improve statistical power in AD prevention trials. METHODS: Baseline and annualized % change in [11C]PIB SUVR and DVR were computed for a global (cortical) and regional (early) composite from scans of 237 cognitively unimpaired subjects from the OASIS-3 database ( www.oasis-brains.org ). Bland-Altman and correlation analyses were used to assess the relationship between SUVR and DVR. General linear models and linear mixed effects models were used to determine effects of age, sex, and APOE-ε4 carriership on baseline and longitudinal amyloid burden. Finally, differences in statistical power of SUVR and DVR (cortical or early composite) were assessed considering three anti-amyloid trial scenarios: secondary prevention trials including subjects with (1) intermediate-to-high (Centiloid > 20.1), or (2) intermediate (20.1 < Centiloid ≤ 49.4) amyloid burden, and (3) a primary prevention trial focusing on subjects with low amyloid burden (Centiloid ≤ 20.1). Trial scenarios were set to detect 20% reduction in accumulation rates across the whole population and in APOE-ε4 carriers only. RESULTS: Although highly correlated to DVR (ρ = .96), cortical SUVR overestimated DVR cross-sectionally and in annual % change. In secondary prevention trials, DVR required 143 subjects per arm, compared with 176 for SUVR. Both restricting inclusion to individuals with intermediate amyloid burden levels or to APOE-ε4 carriers alone further reduced sample sizes. For primary prevention, SUVR required less subjects per arm (n = 855) compared with DVR (n = 1508) and the early composite also provided considerable sample size reductions (n = 855 to n = 509 for SUVR, n = 1508 to n = 734 for DVR). CONCLUSION: Sample sizes in AD secondary prevention trials can be reduced by the acquisition of dynamic PET scans and/or by restricting inclusion to subjects with intermediate amyloid burden or to APOE-ε4 carriers only. Using a targeted early composite only leads to reductions of sample size requirements in primary prevention trials. These findings support strategies to enable smaller Proof-of-Concept Phase II clinical trials to better streamline drug development

    Strategies to reduce sample sizes in Alzheimer’s disease primary and secondary prevention trials using longitudinal amyloid PET imaging

    Get PDF
    BACKGROUND: Detecting subtle-to-moderate biomarker changes such as those in amyloid PET imaging becomes increasingly relevant in the context of primary and secondary prevention of Alzheimer's disease (AD). This work aimed to determine if and when distribution volume ratio (DVR; derived from dynamic imaging) and regional quantitative values could improve statistical power in AD prevention trials. METHODS: Baseline and annualized % change in [11C]PIB SUVR and DVR were computed for a global (cortical) and regional (early) composite from scans of 237 cognitively unimpaired subjects from the OASIS-3 database ( www.oasis-brains.org ). Bland-Altman and correlation analyses were used to assess the relationship between SUVR and DVR. General linear models and linear mixed effects models were used to determine effects of age, sex, and APOE-ε4 carriership on baseline and longitudinal amyloid burden. Finally, differences in statistical power of SUVR and DVR (cortical or early composite) were assessed considering three anti-amyloid trial scenarios: secondary prevention trials including subjects with (1) intermediate-to-high (Centiloid > 20.1), or (2) intermediate (20.1 < Centiloid ≤ 49.4) amyloid burden, and (3) a primary prevention trial focusing on subjects with low amyloid burden (Centiloid ≤ 20.1). Trial scenarios were set to detect 20% reduction in accumulation rates across the whole population and in APOE-ε4 carriers only. RESULTS: Although highly correlated to DVR (ρ = .96), cortical SUVR overestimated DVR cross-sectionally and in annual % change. In secondary prevention trials, DVR required 143 subjects per arm, compared with 176 for SUVR. Both restricting inclusion to individuals with intermediate amyloid burden levels or to APOE-ε4 carriers alone further reduced sample sizes. For primary prevention, SUVR required less subjects per arm (n = 855) compared with DVR (n = 1508) and the early composite also provided considerable sample size reductions (n = 855 to n = 509 for SUVR, n = 1508 to n = 734 for DVR). CONCLUSION: Sample sizes in AD secondary prevention trials can be reduced by the acquisition of dynamic PET scans and/or by restricting inclusion to subjects with intermediate amyloid burden or to APOE-ε4 carriers only. Using a targeted early composite only leads to reductions of sample size requirements in primary prevention trials. These findings support strategies to enable smaller Proof-of-Concept Phase II clinical trials to better streamline drug development

    ATENA–A Novel Rapidly Manufactured Medical Invasive Ventilator Designed as a Response to the COVID-19 Pandemic: Testing Protocol, Safety, and Performance Validation

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    Background: The urgent need for mechanical ventilators to support respiratory insufficiency due to SARS-CoV-2 led to a worldwide effort to develop low-cost, easily assembled, and locally manufactured ventilators. The ATENA ventilator project was developed in a community-based approach targeting the development, prototyping, testing, and decentralized manufacturing of a new mechanical ventilator. Objective: This article aims to demonstrate ATENA's adequate performance and safety for clinical use. Material: ATENA is a low-cost ventilator that can be rapidly manufactured, easily assembled, and locally produced anywhere in the world. It was developed following the guidelines and requirements provided by European and International Regulatory Authorities (MHRA, ISO 86201) and National Authorities (INFARMED). The device was thoroughly tested using laboratory lung simulators and animal models. Results: The device meets all the regulatory requirements for pandemic ventilators. Additionally, the pre-clinical experiences demonstrated security and adequate ventilation and oxygenation, in vivo. Conclusion: The ATENA ventilator had a good performance in required tests in laboratory scenarios and pre-clinical studies. In a pandemic context, ATENA is perfectly suited for safely treating patients in need of mechanical ventilation.Financial support and sponsorship by CEiiA, INOV4COVID program, donations from scientific patronage, and commercial sales

    Tamanho de amostra para avaliação de caracteres de cenoura em sistemas de cultivo agroecológico.

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    O correto dimensionamento de experimentos deve ser utilizado para que se possa reduzir o erro experimental e com isso, maximizar a precisão das informações obtidas. O objetivo deste trabalho foi estimar o número mínimo de famílias e de plantas por parcela para avaliação de caracteres de raiz em uma população de cenoura cultivada em sistema agroecológico. Os ensaios foram conduzidos no verão de 2006/2007 em duas propriedades com cultivo agroecológico em Brasília: Associação Mokiti Okada, que segue modelo de Agricultura Natural em Brazlândia-DF e Núcleo Rural Taguatinga, seguindo modelo de Agricultura Orgânica em Taguatinga-DF. Foram avaliadas 100 famílias de meio-irmãos de cenoura dispostas em delineamento de blocos casualizados com duas repetições e parcelas de 1 m2. Foram colhidas 20 plantas competitivas por parcela e avaliadas individualmente para os caracteres comprimento de raiz, diâmetro da raiz, massa da raiz, diâmetro do xilema da raiz, relação diâmetro do xilema/diâmetro da raiz, tipo de ponta da raiz, tipo de ombro da raiz, parâmetro a* para os tecidos xilema e floema. Foi realizada análise de variância conjunta e para cada sistema, com informação entre e dentro de parcelas. Foram realizadas ainda análises de representatividade do número mínimo de famílias e de plantas para representar uma população de cenoura. Foi verificado que uma amostra de 18 plantas competitivas/parcela coletadas em ensaios com 2 repetições, bem como de 74 famílias, são suficientes para garantir uma adequada avaliação de famílias meio-irmãos de cenoura para os caracteres estudados

    Terms of international classification for Nursing Practice in motor and physical rehabilitation

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    OBJECTIVE To validate terms of nursing language especially for physical-motor rehabilitation and map them to the terms of ICNP® 2.0. METHOD A methodology research based on document analysis, with collection and analysis of terms from 1,425 records. RESULTS 825 terms were obtained after the methodological procedure, of which 226 had still not been included in the ICNP® 2.0. These terms were distributed as follows: 47 on the Focus axis; 15 on the Judgment axis; 31 on the Action axis; 25 on the Location axis; 102 on the Means axis; three on the Time axis; and three on the Client axis. All non-constant terms in ICNP® have been validated by experts, having reached an agreement index ≥0.80. CONCLUSION The ICNP® is applicable and used in nursing care for physical-motor rehabilitation
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