2,700 research outputs found

    Capacitance effect on the oscillation and switching characteristics of spin torque oscillators

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    We have studied the capacitance effect on the oscillation characteristics and the switching characteristics of the spin torque oscillators (STOs). We found that when the external field is applied, the STO oscillation frequency exhibits various dependences on the capacitance for injected current ranging from 8 to 20 mA. The switching characteristic is featured with the emerging of the canted region; the canted region increases with the capacitance. When the external field is absent, the STO free-layer switching time exhibits different dependences on the capacitance for different injected current. These results help to establish the foundation for capacitance-involved STO modeling.published_or_final_versio

    Synthesis and characterization of silica-encapsulated iron oxide nanoparticles

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    Session PD: Structured MaterialsThe properties of magnetic core-shell nanoparticles greatly depend on their core sizes and shell materials. Silica shell can prevent the magnetic nanoparticles from corrosion and agglomeration. In addition, the hydrolyzed silica can provide silanol groups to facilitate surface biofunctionalization. In this paper, superparamagnetic Fe3O4 nanoparticles coated with SiO2 shell were prepared by a one-pot water-in-oil microemulsion method. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM) were utilized to characterize the morphology and magnetic properties of the synthesized nanoparticles. The results indicated that by tuning the water/surfactant molar ratio (Wo) of the microemulsion system, core size of the resulting Fe3O4 nanoparticles can be altered. The size-controllable silica-encapsulated Fe3O4 superparamagnetic nanoparticles have great potential to be applied as multifunctional tracer materials for magnetic particle imaging (MPI).published_or_final_versio

    The role of proheparanase in synaptic plasticity at the hippocampus

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    Abstract no. P-110Perineuronal heparan sulfate (HS) moieties are implicated in the modulation of neurotransmission by controlling the functional properties of AMPA-type glutamate receptors. We hypothesize that neuronal mechanisms modulate peri-synaptic HS level, thereby regulating synaptic strength and plasticity. To address this, basal synaptic strength and long-term changes in synaptic efficacy in the Schaffer collateral pathway of the rat hippocampus were assessed in relation to strategies that perturb peri-synaptic HS. In hippocampal slices, heparitinase treatment led to dose-dependent attenuation of long-term potentiation (LTP) in correlation with loss of perineuronal HS …postprin

    Evolving frontiers in severe polytrauma management: refining the essential principles

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    This editorial aims to refine the severe polytrauma management principles. While keeping ABCDE priorities, the termination of futile resuscitation and the early use of tourniquet to stop exsanguinating limb bleeding are crucial. Difficult-airway-management (DAM) is by a structured 5-level approach. The computerised tomography (CT) scanner is the tunnel to death for hemodynamically unstable patients. Focused Abdominal Sonography for Trauma-Ultrasonography (FAST USG) has replaced diagnostic peritoneal lavage (DPL) and is expanding to USG life support. Direct whole-body multidetector-row computed tomography (MDCT) expedites diagnosis & treatment. Non-operative management is a viable option in rapid responders in shock. Damage control resuscitation comprising of permissive hypotension, hemostatic resuscitation & damage control surgery (DCS) help prevent the lethal triad of trauma. Massive transfusion protocol reduces mortality and decreases the blood requirement. DCS attains rapid correction of the deranged physiology. Mortality reduction in major pelvic disruption requires a multi-disciplinary protocol, the novel pre-peritoneal pelvic packing and the angio-embolization. When operation is the definitive treatment for injury, prevention is best therapy. © Penerbit Universiti Sains Malaysia, 2013.published_or_final_versio

    Split-Drain Magnetic Field-Effect Transistor Channel Charge Trapping and Stress Induced Sensitivity Deterioration

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    Session EB: Materials for ApplicationsThis paper proposed an analytical model on the deterioration of magnetic sensitivity of sectorial split-drain magnetic field-effect transistors (SD-MAGFETs). The deterioration is governed by the trap fill rate at the channel boundary traps, which is geometric dependent. Experimental results are presented which show good consistency with the analytical derivation. The deterioration is the most severe at a sector angle of 54.6°, which shows a design tradeoff with sensing hysteresis. Design guidelines for sectorial SD-MAGFET to obtain high sensitivity hysteresis and slow sensitivity deterioration are also presented which provide important information for efficient design. © 2013 IEEE.published_or_final_versio

    A randomized control trial to evaluate the effect of adjuvant selective laser trabeculoplasty versus medication alone in primary open-angle glaucoma: preliminary results

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    BACKGROUND: The objective of this study was to investigate the effects of adjuvant selective laser trabeculoplasty (SLT) versus medication alone on intraocular pressure (IOP) control, medication use, and quality of life in patients with primary open-angle glaucoma. METHODS: This prospective, randomized control study recruited 41 consecutive primary open-angle glaucoma subjects with medically-controlled IOP /=0.4) or between the two treatment groups (P>/=0.2). CONCLUSION: A single session of adjuvant SLT provided further reductions in IOP and medication without substantial changes in quality of life or medication tolerability at 6 months.published_or_final_versio

    Pixel-to-pixel fiber-coupled emissive micro-light-emitting diode arrays

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    We report on an integrated fiber-coupled bi-linear micro-light-emitting diode array, serving as a portable microdisplay system. The fiber bundle transforms the bi-linearly arranged optical signals from the emissive array into a 6-by-8 pixel microdisplay, offering a crisp and clear optical output. The pixel-to-pixel coupling arrangement ensures optical coupling efficiency. Due to the narrow acceptance cones of optical fibers, individual pixels can be well resolved with minimal crosstalk. The performance and functionality of this optical system is fully evaluated. A model to determine the fiber-coupling efficiency was constructed; it was found that the simulated results compare well with the measured data.published_or_final_versio

    A novel duplication at the putative DNA polymerase alpha arrest site and a founder mutation in Chinese in the IVD gene underlie isovaleric acidaemia

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    Isovaleric acidaemia is a rare inherited organic acidaemia associated with a characteristic odour in affected patients. Fewer than 40 causative mutations have been reported to date. We report a case in a Hong Kong Chinese neonate who presented with respiratory distress and acute encephalopathy requiring aggressive resuscitation and treatment. Residual gross motor developmental delay was still observed at the age of 16 months. The child was subsequently found to harbour a known missense mutation (c.A1199G [p.Y371C]) and a novel 4-bp duplication (c.1148_1151dupGCTA [p.Y355X]) in the IVD gene. We suggest that the former is a founder mutation in the Chinese population and propose an explanation for the duplication event. Strategies that may achieve early diagnosis and prompt treatment include raising awareness of this condition, implementation of a tandem mass spectrometry neonatal screening programme, and local acquisition of appropriate medications for these metabolic diseases.published_or_final_versio

    Transient sensitivity of sectorial split-drain magnetic field-effect transistor

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