719 research outputs found

    Vertical spinal electronic device with large room temperature magnetoresistance

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    We report experimental transport measurements of a vertical hybrid ferromagnetic (FM)/III-V semiconductor (SC)/ferromagnetic(FM) type structure, i.e., Cr(20ML)/Co(15ML)/GaAs(50 nm, n-type)/Al/sub 0.3/Ga/sub 0.7/As(200 nm, n-type)/FeNi(30 nm). The current-voltage (I-V) characteristics reveal Schottky/tunneling type behavior in the direction of FeNi/Semiconductor/Co and observed to be dependent on external magnetic field. The magnetoresistance (MR) behavior shows a strong dependence on the measured current and field. At low fields no significant change in MR has been observed with increasing current. However, at high fields the MR initially increases with increasing current and becomes stable beyond a critical current of 10 /spl mu/A. A maximum of 12% change in the MR has been observed at room temperature, which is far larger than that of the conventional AMR effect. This property of the device could be utilized as field sensors or magnetic logic devices

    Managing complex medication regimens: perspectives of consumers with osteoarthritis and healthcare professionals

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    BACKGROUND: Managing medications is complex, particularly for consumers with multiple coexisting conditions for whom benefits and adverse effects are unpredictable and health priorities may be variable. OBJECTIVE: To investigate perceptions of and experiences with managing drug regimens from the perspectives of consumers with osteoarthritis and coexisting chronic conditions and of healthcare professionals from diverse backgrounds. METHODS: Using an exploratory research design, focus groups were formed with 34 consumers and 19 healthcare professionals. Individual interviews were undertaken with 3 community medical practitioners. RESULTS: Consumers\u27 management of medications was explored in terms of 3 themes: administration of medications, provision of information, and the perceived role of healthcare professionals. In general, consumers lacked understanding regarding the reason that they were prescribed certain medications. Since all consumer participants had at least 2 chronic conditions, they were taking many drugs to relieve undesirable symptoms. Some consumers were unable to achieve improved pain relief and were reluctant to take analgesics prescribed on an as - needed basis. Healthcare professionals discussed the importance of using non-pharmacologic measures to improve symptoms; however, consumers stated that physicians encourage them to continue using medications, often for prolonged periods, even when these agents are not helpful. CONCLUSIONS: Consumers were dissatisfied about the complexity of their medication regimens and also lacked understanding as to how to take their drugs effectively. Dedicated time should be devoted during medical consultations to facilitate verbal exchange of information about medications. Pharmacists must communicate regularly with physicians about consumers\u27 medication needs to help preempt any problems that may arise. Instructions need to be revised through collaboration between physicians and pharmacists so that &quot;as needed&quot; directions provide more explicit advice about when and how to use such drugs. Future research, using large, generalizable samples, should examine trends related to consumers\u27 experiences of symptomatic relief from chronic conditions and their understandings about medications. <br /

    Balance assessment in Multiple Sclerosis and cerebellar ataxia: rationale, protocol and demographic data

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    A core set of standardized balance measures are required for use in rehabilitation among people with multiple sclerosis (MS) and cerebellar ataxia. An earlier systematic review and Delphi survey identified the Berg Balance Scale (BBS), the Timed Up and Go test (TUG), Posture and Gait sub-component of the International Co-operative Ataxia Rating Scale (PG of ICARS) and the gait, sitting and stance sub-components of the Scale for the Assessment and Rating of Ataxia (SARA Bal) as suitable balance measures. This study aims to estimate the reliability, validity and interpretability of these measures. This study will recruit 60 participants with multiple sclerosis with secondary cerebellar involvement across four centres in New Zealand and the United States of America. Participants will be assessed and videotaped performing the BBS, TUG, SARA Bal and PG of ICARS by trained physiotherapists. Barthel Index, Expanded Disability Status Scale (EDSS), Disease duration, ICARS and SARA will also be assessed to determine validity. A second assessment to determine reliability will be conducted by assessors watching the video-recording. Data collection is in progress, 44 samples have been collected and the demographic data are presented. The findings of this study will recommend a core set of reliable, valid and interpretable measures that are suitable for clinical practice and research for the assessment of balance among adults with MS and cerebellar ataxia. Minimal Clinically Important Difference (MCID) and cut-off scores to predict the use of assistive walking device will be established

    Domain-wall pinning, nonadiabatic spin-transfer torque, and spin-current polarization in permalloy wires doped with vanadium

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    Copyright © 2010 The American Physical SocietyUsing pulsed-current measurements we investigate the domain-wall depinning via spin-transfer torque from pinning potentials in V-doped Ni80Fe20 wires. The domain-wall depinning boundary, showing the variation of threshold current density with longitudinal magnetic field is measured and reproduced using micromagnetic simulations. This method allows us to determine the spin-current polarization and nonadiabaticity parameter in these materials. By increasing the V concentration we show that the nonadiabaticity parameter is increased while the Gilbert damping is unaffected. On the other hand the spin-current polarization is decreased, resulting in larger threshold current densities

    The selectivity, voltage-dependence and acid sensitivity of the tandem pore potassium channel TASK-1 : contributions of the pore domains

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    We have investigated the contribution to ionic selectivity of residues in the selectivity filter and pore helices of the P1 and P2 domains in the acid sensitive potassium channel TASK-1. We used site directed mutagenesis and electrophysiological studies, assisted by structural models built through computational methods. We have measured selectivity in channels expressed in Xenopus oocytes, using voltage clamp to measure shifts in reversal potential and current amplitudes when Rb+ or Na+ replaced extracellular K+. Both P1 and P2 contribute to selectivity, and most mutations, including mutation of residues in the triplets GYG and GFG in P1 and P2, made channels nonselective. We interpret the effects of these—and of other mutations—in terms of the way the pore is likely to be stabilised structurally. We show also that residues in the outer pore mouth contribute to selectivity in TASK-1. Mutations resulting in loss of selectivity (e.g. I94S, G95A) were associated with slowing of the response of channels to depolarisation. More important physiologically, pH sensitivity is also lost or altered by such mutations. Mutations that retained selectivity (e.g. I94L, I94V) also retained their response to acidification. It is likely that responses both to voltage and pH changes involve gating at the selectivity filter

    Leveraging Health Behavior and Communication Theories to Support Adolescent and Young Adults: Conceptualizing Social Media Wellness in Relation to Disordered Eating

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    Social media platforms like Instagram serve as an important mechanism for transmitting social information and influence. However, the nature and use of these platforms are known to perpetuate eating disorders (EDs) or further disorder eating symptoms. This concept paper proposes merging health behavior and communication theory to create a comprehensive and applicable framework for remediating pro-eating disorder social media content among people who have eating disorders. To this end, the Social Media Wellness Model, which is adapted from the Health Belief Model, the Uses and Gratifications approach, the MAIN model of media affordances, and media literacy training, is proposed. This paper shows how theoretical model components can be mapped back to behaviors typified by individuals with EDs, or those predisposed to developing EDs. Subsequently, we propose a training intervention to highlight salient literacy cues, and outline next steps for testing and developing this model with the ongoing support of a community advisory board (CAB). Creating a CAB with individuals who have lived experience of an ED or disordered eating, and who use social media, will be vital to testing the applicability of this conceptual Social Media Wellness Model for ED recovery
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