44 research outputs found

    Mitochondrial respiratory states and rate

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    As the knowledge base and importance of mitochondrial physiology to human health expands, the necessity for harmonizing the terminologyconcerning mitochondrial respiratory states and rates has become increasingly apparent. Thechemiosmotic theoryestablishes the mechanism of energy transformationandcoupling in oxidative phosphorylation. Theunifying concept of the protonmotive force providestheframeworkfordeveloping a consistent theoretical foundation ofmitochondrial physiology and bioenergetics.We followguidelines of the International Union of Pure and Applied Chemistry(IUPAC)onterminology inphysical chemistry, extended by considerationsofopen systems and thermodynamicsof irreversible processes.Theconcept-driven constructive terminology incorporates the meaning of each quantity and alignsconcepts and symbols withthe nomenclature of classicalbioenergetics. We endeavour to provide a balanced view ofmitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes.Uniform standards for evaluation of respiratory states and rates will ultimatelycontribute to reproducibility between laboratories and thussupport the development of databases of mitochondrial respiratory function in species, tissues, and cells.Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    Mitochondrial physiology

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    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    Mitochondrial physiology

    Get PDF
    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    Prolonged supine hypertension due to midodrine use in an orthostatic hypotensive child

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    Midodrine hydrochloride is a potent peripherally-acting alpha 1 agonist that is well absorbed and rapidly metabolized to its active metabolite. It has been used for the treatment of refractory syncope but has the important side effect of supine hypertension. A 10-year-old boy with severe symptomatic orthostatic hypotension was treated with midodrine. After therapy, syncope attacks ceased but he suffered nighttime headaches, nausea, transient rash and itchy/prickly scalp. Midodrine was discontinued when supine hypertension was noticed. However, his supine hypertension continued until day 19 after discontinuation. This case shows that patients receiving midodrine should be observed for supine hypertension for a prolonged period

    Structural, optical and Schottky diode properties of Cu2ZnSnS4 thin films grown by two-stage method

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    CZTS thin film was prepared by a two-stage process comprising sputter deposition of metallic Cu, Zn, and Sn layers followed annealing treatment of the metallic precursors in a sulfur atmosphere at 560 °C for 3 min. The CZTS thin film was investigated in the way of structural, optical and electrical properties. The XRD pattern of Cu-poor and Zn-rich CZTS thin film was dominated by characteristic peaks of kesterite CZTS planes. Raman spectra of the film ensured formation of kesterite CZTS phase and displayed formation of CTS and ZnS phases. Dense and polycrystalline surface features were observed in SEM images of CZTS thin film. Band–band transitions was not observed due to the probable concentration of deep acceptor levels in this material. The diode parameters of Mo/CZTS/Al structure such as ideality factor, barrier height and serial resistance were calculated employing temperature dependent I–V characteristics of Mo/CZTS/Al diode structure. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

    Growth of Cu 2 ZnSnS 4 (CZTS) thin films using short sulfurization periods

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    In this study CZTS thin films were grown by a two-stage process that involved sequential sputter deposition of metallic Cu, Zn, and Sn layers on Mo coated glass substrates followed by RTP annealing at 530 and 560 °C for various dwell times (1, 60, and 180 s). CZTS thin films obtained by reaction at different sulfurization temperatures and reaction times were characterized employing XRD, Raman spectroscopy, SEM, EDX, and photoluminescence. It was observed that it is possible to obtain Cu-poor and Zn-rich CZTS thin films with short dwell time of reactions. XRD pattern and Raman spectra of the films showed formation of kesterite CZTS structure and some secondary phases such as CuS, SnS, SnS 2 . The full-width-at-half-maximum (FWHM) values extracted from the (112) diffraction peaks of the CZTS thin films showed that extension of the sulfurization time provides better crystalline quality except for the CZTS560-60 thin film. SEM surface microstructure of the films displayed non-uniform, dense, and polycrystalline structure. The optical band gap of the films as determined by photoluminescence was found to be about 1.36-1.38 eV. © 2019 IOP Publishing Ltd
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