2,653 research outputs found

    Interdisciplinary Stroke Rehabilitation Delivered by a Humanoid Robot: Simultaneous vs. Alternating Therapy Schedules

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    A great number of stroke survivors experience disabilities in multiple domains (e.g., aphasia, hemiparesis). However, no previous research has investigated how treatment in one domain (e.g., speech therapy) affects the progress in other areas (e.g., physical recovery). The current study is comparing two therapy schedules: simultaneous where a patient receives speech AND physical therapy services for four weeks; and alternating where a patient receives speech therapy for four weeks and then receives physical therapy for four weeks. This interdisciplinary intervention is delivered by a humanoid robot that can potentially enhance the intensity and accessibility of stroke rehabilitation

    2D perovskite stabilized phase-pure formamidinium perovskite solar cells.

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    Compositional engineering has been used to overcome difficulties in fabricating high-quality phase-pure formamidinium perovskite films together with its ambient instability. However, this comes alongside an undesirable increase in bandgap that sacrifices the device photocurrent. Here we report the fabrication of phase-pure formamidinium-lead tri-iodide perovskite films with excellent optoelectronic quality and stability. Incorporation of 1.67 mol% of 2D phenylethylammonium lead iodide into the precursor solution enables the formation of phase-pure formamidinium perovskite with an order of magnitude enhanced photoluminescence lifetime. The 2D perovskite spontaneously forms at grain boundaries to protect the formamidinium perovskite from moisture and suppress ion migration. A stabilized power conversion efficiency (PCE) of 20.64% (certified stabilized PCE of 19.77%) is achieved with a short-circuit current density exceeding 24 mA cm-2 and an open-circuit voltage of 1.130 V, corresponding to a loss-in-potential of 0.35 V, and significantly enhanced operational stability

    Perovskite-polymer composite cross-linker approach for highly-stable and efficient perovskite solar cells.

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    Manipulation of grain boundaries in polycrystalline perovskite is an essential consideration for both the optoelectronic properties and environmental stability of solar cells as the solution-processing of perovskite films inevitably introduces many defects at grain boundaries. Though small molecule-based additives have proven to be effective defect passivating agents, their high volatility and diffusivity cannot render perovskite films robust enough against harsh environments. Here we suggest design rules for effective molecules by considering their molecular structure. From these, we introduce a strategy to form macromolecular intermediate phases using long chain polymers, which leads to the formation of a polymer-perovskite composite cross-linker. The cross-linker functions to bridge the perovskite grains, minimizing grain-to-grain electrical decoupling and yielding excellent environmental stability against moisture, light, and heat, which has not been attainable with small molecule defect passivating agents. Consequently, all photovoltaic parameters are significantly enhanced in the solar cells and the devices also show excellent stability

    Gate tunable optical absorption and band structure of twisted bilayer graphene

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    We report the infrared transmission measurement on electrically gated twisted bilayer graphene. The optical absorption spectrum clearly manifests the dramatic changes such as the splitting of inter-linear-band absorption step, the shift of inter-van Hove singularity transition peak, and the emergence of very strong intra-valence (intra-conduction) band transition. These anomalous optical behaviors demonstrate consistently the non-rigid band structure modification created by the ion-gel gating through the layer-dependent Coulomb screening. We propose that this screening-driven band modification is an universal phenomenon that persists to other bilayer crystals in general, establishing the electrical gating as a versatile technique to engineer the band structures and to create new types of optical absorptions that can be exploited in electro-optical device application.Comment: 13 pages, 4 figure

    Increasing trends in hospital care burden of atrial fibrillation in Korea, 2006 through 2015

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    ObjectiveTemporal changes in the healthcare burden of atrial fibrillation (AF) are less well known in rapidly ageing Asian countries. We examined trends in hospitalisations, costs, treatment patterns and outcomes related to AF in Korea.MethodsUsing the National Health Insurance Service (NHIS) database involving the entire adult Korean population (n=41 701 269 in 2015), we analysed a nationwide AF cohort representing 931 138 patients with AF. We studied all hospitalisations due to AF from 2006 to 2015.ResultsOverall, hospitalisations for AF increased by 420% from 767 to 3986 per 1 million Korean population from 2006 to 2015. Most admissions occurred in patients aged ≥70 years, and the most frequent coexisting conditions were hypertension, heart failure and chronic obstructive pulmonary disease. Hospitalisations mainly due to major bleeding and AF control increased, whereas hospitalisations mainly due to ischaemic stroke and myocardial infarction decreased. The total cost of care increased even after adjustment for inflation from €68.4 million in 2006 to €388.4 million in 2015, equivalent to 0.78% of the Korean NHIS total expenditure. Overall in-hospital mortality decreased from 7.5% in 2006 to 4.3% in 2015. The in-hospital mortality was highest in patients ≥80 years of age (7.7%) and in patients with chronic kidney disease (7.4%).ConclusionsAF hospitalisations have increased exponentially over the past 10 years in Korea, in association with an increase in comorbid chronic diseases. Mortality associated with AF hospitalisations decreased during the last decade, but hospitalisation costs have markedly increased.</jats:sec

    Acute Shunt Malfunction after Cesarean Section Delivery: A Case Report

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    Shunt malfunctions that require surgical intervention during pregnancy and the postpartum period are rare. Furthermore, no study has reported on an acute shunt malfunction immediately after cesarean section. Here, we describe the case of a 32-yr-old woman who became drowsy 12 hr after cesarean section delivery of her second child. She had a ventriculoperitoneal shunt placed to treat hydrocephalus associated with meningitis at 26 yr of age. Marked ventriculomegaly was seen on brain computed tomography and her consciousness recovered temporarily after aspirating cerebrospinal fluid from the flushing device. At surgery, the distal catheter tip was plugged by a blood clot. We believe that the blood spilled over during the cesarean section. The clogged catheter end was simply cut off and the remaining catheter was repositioned in the peritoneal cavity. Her consciousness recovered fully
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