46 research outputs found

    Catalytic C(sp3)-H bond activation in tertiary alkylamines.

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    The development of robust catalytic methods to assemble tertiary alkylamines provides a continual challenge to chemical synthesis. In this regard, transformation of a traditionally unreactive C-H bond, proximal to the nitrogen atom, into a versatile chemical entity would be a powerful strategy for introducing functional complexity to tertiary alkylamines. A practical and selective metal-catalysed C(sp3)-H activation facilitated by the tertiary alkylamine functionality, however, remains an unsolved problem. Here, we report a Pd(II)-catalysed protocol that appends arene feedstocks to tertiary alkylamines via C(sp3)-H functionalization. A simple ligand for Pd(II) orchestrates the C-H activation step in favour of deleterious pathways. The reaction can use both simple and complex starting materials to produce a range of multifaceted γ-aryl tertiary alkylamines and can be rendered enantioselective. The enabling features of this transformation should be attractive to practitioners of synthetic and medicinal chemistry as well as in other areas that use biologically active alkylamines

    Experience of nurses in the process of donation of organs and tissues for transplant

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    OBJETIVO: conhecer o significado da ação de enfermeiros no processo de doação para viabilizar órgãos e tecidos para transplante. MÉTODO: pesquisa qualitativa, com abordagem da Fenomenologia Social, foi realizada por meio de entrevistas individuais com dez enfermeiros de três Serviços de Procura de Órgãos e Tecidos da cidade de São Paulo. RESULTADOS: a vivência dos enfermeiros no processo de doação foi representada pelas categorias: obstáculos vivenciados no processo de doação e intervenções realizadas. O significado da ação para viabilizar órgãos e tecidos para transplante foi descrito pelas categorias: mudar paradigmas, humanizar o processo de doação, aumentar a doação e salvar vidas. CONSIDERAÇÕES FINAIS: o conhecimento da vivência dos enfermeiros nesse processo oferece subsídios aos profissionais de saúde, que atuam em diferentes realidades, sinalizando estratégias para otimizar a obtenção de órgãos e tecidos para transplante.OBJECTIVE: to investigate the meaning of the action of nurses in the donation process to maintain the viability of organs and tissues for transplantation. METHOD: this qualitative study with a social phenomenological approach was conducted through individual interviews with ten nurses of three Organ and Tissue Procurement Services of the city of São Paulo. RESULTS: the experience of the nurses in the donation process was represented by the categories: obstacles experienced in the donation process, and interventions performed. The meaning of the action to maintain the viability of organs and tissues for transplantation was described by the categories: to change paradigms, to humanize the donation process, to expand the donation, and to save lives. FINAL CONSIDERATIONS: knowledge of the experience of the nurses in this process is important for healthcare professionals who work in different realities, indicating strategies to optimize the procurement of organs and tissues for transplantation.OBJETIVO: conocer el significado de la acción de enfermeros en el proceso de donación órganos y tejidos para dar viabilidad al trasplante. MÉTODO: investigación cualitativa, con abordaje de la Fenomenología Social, fue realizada por medio de entrevistas individuales con diez enfermeros de tres Servicios de Búsqueda de Órganos y Tejidos de la ciudad de Sao Paulo. RESULTADOS: la vivencia de los enfermeros en el proceso de donación fue representada por las categorías: obstáculos experimentados en el proceso de donación e intervenciones realizadas. El significado de la acción para dar viabilidad al proceso trasplante de órganos y tejidos fue descrito por las categorías: cambiar paradigmas, humanizar el proceso de donación, aumentar la donación y salvar vidas. CONSIDERACIONES FINALES: el conocimiento de la vivencia de los enfermeros en ese proceso ofrece informaciones importantes a los profesionales de salud que actúan en diferentes realidades, señalando estrategias para optimizar la obtención de órganos y tejidos para trasplante

    A Strange Term in the Homogenization of Parabolic Equations with Two Spatial and Two Temporal Scales

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    We study the homogenization of a parabolic equation with oscillations in both space and time in the coefficient a x/ε, t/ε 2 in the elliptic part and spatial oscillations in the coefficient ρ x/ε that is multiplied with the time derivative ∂ t u ε . We obtain a strange term in the local problem. This phenomenon appears as a consequence of the combination of the spatial oscillation in ρ x/ε and the temporal oscillation in a x/ε, t/ε 2 and disappears if either of these oscillations is removed

    Effect of modelling the air in rooms on the prediction of vibration transmission in cross-laminated timber buildings

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    Timber buildings are intrinsically lightweight and hence can be susceptible to low-frequency vibrations and structure-borne noise. So, within the development of technical solutions for mitigating unwanted vibrations and noise, accurate and computationally efficient numerical models are considered to be of great value. Such models should take into account all physical phenomena that are relevant for achieving adequate accuracy in predictions, while not being overly detailed so that the computational efficiency is impaired. In this paper, the necessity of modelling the enclosed air in room volumes of buildings made of cross-laminated timber, with respect to the prediction of vibration transmission, is investigated. Coupled structural-acoustic finite element analysis is employed for an example building structure. It is found that modelling the air in the receiver room, i.e. in the room where the vibration response is evaluated, has a marked effect on the vibration transmission between panels
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