78 research outputs found

    Plantograf V18 – new construction and properties

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    ArticleThe article describes Plantograf V18, a planar tactile transducer, which converts the applied pressure into electric signal and enables a graphical presentation of the measured data; the new version V18 comes with some significant improvements and modifications. The device may be used ev erywhere where the pressure distribution between an object and surface is to be determined, e.g. in medicine or automotive industry. The article contains the detailed description of the transducer design and its electronic control circuits, as well as the yet unpublished measurements of pressure sensitivity with 3.5 mm electrodes

    Fundamental Limits on Wavelength, Efficiency and Yield of the Charge Separation Triad

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    In an attempt to optimize a high yield, high efficiency artificial photosynthetic protein we have discovered unique energy and spatial architecture limits which apply to all light-activated photosynthetic systems. We have generated an analytical solution for the time behavior of the core three cofactor charge separation element in photosynthesis, the photosynthetic cofactor triad, and explored the functional consequences of its makeup including its architecture, the reduction potentials of its components, and the absorption energy of the light absorbing primary-donor cofactor. Our primary findings are two: First, that a high efficiency, high yield triad will have an absorption frequency more than twice the reorganization energy of the first electron transfer, and second, that the relative distance of the acceptor and the donor from the primary-donor plays an important role in determining the yields, with the highest efficiency, highest yield architecture having the light absorbing cofactor closest to the acceptor. Surprisingly, despite the increased complexity found in natural solar energy conversion proteins, we find that the construction of this central triad in natural systems matches these predictions. Our analysis thus not only suggests explanations for some aspects of the makeup of natural photosynthetic systems, it also provides specific design criteria necessary to create high efficiency, high yield artificial protein-based triads

    Construction and in vivo assembly of a catalytically proficient and hyperthermostable de novo enzyme

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    Although catalytic mechanisms in natural enzymes are well understood, achieving the diverse palette of reaction chemistries in re-engineered native proteins has proved challenging. Wholesale modification of natural enzymes is potentially compromised by their intrinsic complexity, which often obscures the underlying principles governing biocatalytic efficiency. The maquette approach can circumvent this complexity by combining a robust de novo designed chassis with a design process that avoids atomistic mimicry of natural proteins. Here, we apply this method to the construction of a highly efficient, promiscuous, and thermostable artificial enzyme that catalyzes a diverse array of substrate oxidations coupled to the reduction of H2O2. The maquette exhibits kinetics that match and even surpass those of certain natural peroxidases, retains its activity at elevated temperature and in the presence of organic solvents, and provides a simple platform for interrogating catalytic intermediates common to natural heme-containing enzymes

    Psychology in practice: Guidelines for the provision of psychological services for older adults

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    The practice of psychology covers the range of ages from conception through to the end of life and palliative care. Psychologists practice in a variety of roles, but the majority of these roles involve interactions with nonprofessionals of varying ages. These interactions are governed by codes of ethical practice, whether these are developed by the funding bodies for research activities, professional associations, or regulatory bodies. Ethical codes vary in their format and emphasis, but all have the protection of the public as a major purpose. Often there are special provisions in these codes for particular populations or circumstances. Here we describe the development of ethical guidelines for the practice of psychology with older adults in Australia and report on those guidelines and their supporting literature

    Editorial: Innovative practice

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    Hearing Aid Evaluation Clinic Systems Redesign

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    Hearing Aid Evaluation Clinic Systems Redesign

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