955 research outputs found

    Cation Nuclear Magnetic Resonance (NMR). 7Li- and 23Na-NMR Results Obtained with Human Erythrocytes

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    A short discussion of practical results and theoretical aspects of nuclear magnetic resonance (NMR) on intracellular monovalent cations is presented. 7Li- and 23Na-NMR relaxation studies on human erythrocytes are described which indicate that lithium and sodium ions are essentially free inside the cell. However, there is a contribution to transverse relaxation originating from cations diffusing through electric field gradients imposed by the cytoskeleton, which is reflected in the NMR line shape. 39K-NMR results obtained by other authors for intracellular potassium are compared with the 7Li- and 23Na-NMR results presented here. The few 39K-NMR results obtained so far do not suggest that significant differences in dynamic behavior exist between intracellular potassium and sodium. 39K-NMR studies will, in the future, certainly enhance our understanding of the intracellular state of potassium ions

    Mach’s Principle in a Mixed Newton-Einstein Context

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    A closed physical space, in conjunction with scalar versus pseudo scalar distinctions, and an accordingly adapted Gauss theorem, reveal unexpected perspectives on Mach\u27s principle, the mass-energy theorem, and a bonus insight into the nature of the solutions of the Einstein field equations of gravity

    On Levi-Civita’s Alternating Symbol, Schouten’s Alternating Unit Tensors, CPT, and Quantization

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    The purpose of the present article is to demonstrate that by adopting a unifying differential geometric perspective on certain themes in physics one reaps remarkable new dividends in both microscopic and macroscopic domains. By replacing algebraic objects by tensor-transforming objects and introducing methods from the theory of differentiable manifolds at a very fundamental level we obtain a Kottler-Cartan metric-independent general invariance of the Maxwell field, which in turn makes for a global quantum superstructure for Gauss-Amp`ere and Aharonov-Bohm “quantum integrals.” Beyond this, our approach shows that postulating a Riemannian metric at the quantum level is an unnecessary concept and our differential geometric, or more accurately topological yoga can substitute successfully for statistical mechanics

    Change in environmental barriers experienced over a 5-year period by people living with spinal cord injury in Switzerland:a prospective cohort study

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    STUDY DESIGN: Cohort study with two measurement occasions. OBJECTIVES: To investigate change in environmental barriers experienced by people living with spinal cord injury (SCI) over a 5-year period. SETTING: Community, Switzerland. METHODS: Data were from the Swiss spinal cord injury (SwiSCI) survey. Main outcome measure was the Nottwil Environmental Factors Inventory-Short Form. Random-effects Poisson regression featuring between-within estimation was used to examine predictors of the number of environmental barriers and of its change over time. RESULTS: One thousand five hundred and forty-nine persons participated in Survey 2012 and 1530 participated in Survey 2017; 761 participated in both surveys. In both surveys most participants reported at least three barriers. Leading issues were unfavorable climate, inaccessibility of buildings and public spaces, and lack of or insufficiently adapted means of transportation. Reporting of barriers related to climate, finances, and state services declined over time. Between subjects, having more health problems, lesser physical independence, poorer mental health, and a lower household income were related to a higher number of barriers experienced. Within subjects, improvements in income, physical independence, and mental health over time were related to a reduction in barriers. CONCLUSIONS: Inaccessibility of buildings and places and problems with transportation remained major barriers over a 5-year period and should be priorities of Swiss disability policy. People with reduced mental and physical health, and those with lower income are vulnerable groups deserving specific attention. Policies targeting income and life-long rehabilitation targeting health promotion and maintenance may be suitable means to reduce the experience of environmental barriers
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