Publications by authors named "Im I"

The ever-increasing volume of complex data poses significant challenges to conventional sequential global processing methods, highlighting their inherent limitations. This computational burden has catalyzed interest in neuromorphic computing, particularly within artificial neural networks (ANNs). In pursuit of advancing neuromorphic hardware, researchers are focusing on developing computation strategies and constructing high-density crossbar arrays utilizing history-dependent, multistate nonvolatile memories tailored for multiply-accumulate (MAC) operations.

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Exploring a computing paradigm that blends memory and computation functions is essential for artificial synapses. While memristors for artificial synapses are widely studied due to their energy-efficient structures, random filament conduction in general memristors makes them less preferred for endurability in long-term synaptic modulation. Herein, the topotactic phase transition (TPT) in brownmillerite-phased (110)-SrCoO (SCO) is harnessed to enhance the reversibility of oxygen ion migration through 1-D oxygen vacancy channels.

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The exotic properties of three-dimensional halide perovskites, such as mixed ionic-electronic conductivity and feasible ion migration, have enabled them to challenge traditional memristive materials. However, the poor moisture stability and difficulty in controlling ion transport due to their polycrystalline nature have hindered their use as a neuromorphic hardware. Recently, two-dimensional (2D) halide perovskites have emerged as promising artificial synapses owing to their phase versatility, microstructural anisotropy in electrical and optoelectronic properties, and excellent moisture resistance.

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Two-dimensional (2D) halide perovskites have become a promising class of memristive materials due to their low power consumption, compositional versatility, and microstructural anisotropy in electronics. However, implementing high-performance resistive random-access memory requires a higher reliability and moisture resistance. To address these issues, component studies and attempts to improve the phase stability have been reported but have not been able to achieve sufficient reliability.

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The current memory system is facing obstacles to improvement, and ReRAM is considered a powerful alternative. All-inorganic α-CsPbI perovskite-based ReRAM working by electrochemical mechanism is reported, but the electrochemically active electrode raised difficulty in long-term stable operation, and bulk α-CsPbI device can not show resistive switching behavior with an inert metal top electrode. Herein, by making the α-CsPbI into QDs and applying it to the device with inert Au as the top electrode, the devices working by valence change mechanism are successfully fabricated.

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Accurate simulation of different cell type interactions is crucial for physiological and precisedrug testing. Human tissue-resident macrophages are critical for modulating disease conditions and drug-induced injuries in various tissues; however, their limited availability has hindered their use inmodeling. Therefore, this study aimed to create macrophage-containing organoid co-culture models by directly incorporating human-induced pluripotent stem cell (hiPSC)-derived pre-macrophages into organoid and scaffold cell models.

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Article Synopsis
  • Maintaining ferroelectricity in thin ferroelectric materials is key for advanced nanoelectronics, and 5 at. % yttrium-doped HfZrO (YHZO) thin films show promise by keeping their ferroelectric properties even at just 10 nm thickness.
  • The YHZO/LaSrMnO (LSMO)/SrTiO (STO) heterostructure enhances electron mobility and memory performance in ferroelectric thin film transistors (FeTFTs), achieving impressive metrics like a memory window of 3.7 V.
  • Compared to nonferroelectric materials, YHZO-based FeTFTs demonstrate excellent endurance and stability under stress, paving the way for
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Molecular electronics enables functional electronic behavior via single molecules or molecular self-assembled monolayers, providing versatile opportunities for hybrid molecular-scale electronic devices. Although various molecular junction structures are constructed to investigate charge transfer dynamics, significant challenges remain in terms of interfacial charging effects and far-field background signals, which dominantly block the optoelectrical observation of interfacial charge transfer dynamics. Here, tip-induced optoelectrical engineering is presented that synergistically correlates photo-induced force microscopy and Kelvin probe force microscopy to remotely control and probe the interfacial charge transfer dynamics with sub-10 nm spatial resolution.

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Numerous efforts for emulating organ systems comprised of multiple functional units have driven substantial advancements in bio-realistic electronics and systems. The resistance change behavior observed in diffusive memristors shares similarities with the potential change in biological neurons. Here, the diffusive threshold switching phenomenon in Ag-incorporated organometallic halide perovskites is utilized to demonstrate the functions of afferent neurons.

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Article Synopsis
  • The research focused on the properties of polypropylene (PP) composites mixed with fly ash (FA) and waste stone powder (WSP) through injection molding, creating various formulations.
  • All composites exhibited no surface cracks or fractures, confirming the reliability of the preparation method through thermogravimetric analysis.
  • While tensile strength did not improve, the additions of FA and WSP significantly enhanced bending strength and notched impact energy by 14.58-22.22%, indicating potential uses in industries like artificial stone and flooring.
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Recently, artificial synapses involving an electrochemical reaction of Li-ion have been attributed to have remarkable synaptic properties. Three-terminal synaptic transistors utilizing Li-ion intercalation exhibits reliable synaptic characteristics by exploiting the advantage of non-distributed weight updates owing to stable ion migrations. However, the three-terminal configurations with large and complex structures impede the crossbar array implementation required for hardware neuromorphic systems.

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Submental surface electromyography (sEMG) may provide information about the lingual-palatal pressure (LPP) during swallowing. However, the extent to which changes in age and LPP levels are reflected in different sEMG measures is unclear. This study aimed to understand the effects of age and different levels of submaximal LPPs on submental sEMG peak, average, and integrated values in healthy adults.

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Amphibians and fish show considerable regeneration potential via dedifferentiation of somatic cells into blastemal cells. In terms of dedifferentiation, in vitro cellular reprogramming has been proposed to share common processes with in vivo tissue regeneration, although the details are elusive. Here, we identified the cytoskeletal linker protein desmoplakin (Dsp) as a common factor mediating both reprogramming and regeneration.

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In resistive switching memories or artificial synaptic devices, halide perovskites have attracted attention for their unusual features such as rapid ion migration, adjustable composition, and facile synthesis. Herein, the environmentally friendly and highly air stable CsCuI perovskite films are used as the active layer in the Au/CsCuI/ITO/glass artificial synapses. The device shows variable synaptic plasticities such as long-term and short-term synaptic plasticity, paired-pulse facilitation, and spike-timing-dependent plasticity by combining potentiation and depression along the formation of conductive filaments.

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Human in vitro hepatic models that faithfully recapitulate liver function are essential for successful basic and translational research. A limitation of current in vitro models, which are extensively used for drug discovery and toxicity testing, is the loss of drug metabolic function due to the low expression and activity of cytochrome P450 (CYP450) enzymes. Here, we aimed to generate human pluripotent stem cell-derived hepatic organoids (hHOs) with a high drug metabolic ability.

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Article Synopsis
  • - MoP nanorod-array catalysts were synthesized directly on graphene-coated silicon photocathodes, avoiding secondary phases that reduce efficiency, thanks to the use of a protective graphene layer.
  • - The synthesis method enhances electron transfer and creates multiple catalytic sites, leading to a high solar energy conversion efficiency and stability during hydrogen evolution reactions (HER).
  • - This innovative approach shows low dependence on pH and temperature, making it a promising development for practical applications in photoelectrochemical cells.
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Various technologies are being developed to support safe driving. Among them, ADAS, including LDWS, is becoming increasingly common. This driver assistance system aims to create a safe road environment while compensating for the driver's carelessness.

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Objectives/hypothesis: To demonstrate utility of the Mann Assessment of Swallowing Ability-Cancer (MASA-C) to describe change in swallowing ability in a cohort of HNC patients from pre-C/RT to post-C/RT to follow up at 3 months post-C/RT. An exploratory analysis compared patients treated with radiotherapy (RT) only to patients treated with chemoradiation (CRT).

Study Design: Prospective Cohort.

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Organometallic and all-inorganic halide perovskites (HPs) have recently emerged as promising candidate materials for resistive switching (RS) nonvolatile memory due to their current-voltage hysteresis caused by fast ion migration. Lead-free and all-inorganic HPs have been researched for non-toxic and environmentally friendly RS memory devices. However, only HP-based devices with electrochemically active top electrode (TE) exhibit ultra-low operating voltages and high on/off ratio RS properties.

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Human-induced pluripotent stem cells (hiPSCs) are invaluable sources for drug screening and toxicity tests because of their differentiation potential and proliferative capacity. Recently, the CRISPR-Cas9-mediated homologous recombination system has enabled reporter knock-ins at desired loci in hiPSCs, and here, we generated a hiPSC reporter line expressing mCherry-tagged cytochrome P450 1A1 (CYP1A1), which can be utilized to screen for the modulators of aryl hydrocarbon receptor (AHR) in live cells. CYP1A1-mCherry hiPSCs exhibited typical characteristics of pluripotent stem cells such as marker expression, differentiation potential, and normal karyotype.

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Background: Fabry disease (FD) is a recessive X-linked lysosomal storage disorder caused by α-galactosidase A (GLA) deficiency. Although the mechanism is unclear, GLA deficiency causes an accumulation of globotriaosylceramide (Gb3), leading to vasculopathy.

Methods: To explore the relationship between the accumulation of Gb3 and vasculopathy, induced pluripotent stem cells generated from four Fabry patients (FD-iPSCs) were differentiated into vascular endothelial cells (VECs).

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Human induced pluripotent stem cells (hiPSCs) are reprogrammed from somatic cells and are regarded as promising sources for regenerative medicine and disease research. Recently, techniques for analyses of individual cells, such as single-cell RNA-Seq and mass cytometry, have been used to understand the stem cell reprogramming process in the mouse. However, the reprogramming process in hiPSCs remains poorly understood.

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The electrical switching behavior of the GeTe phase-changing material grown by atomic layer deposition is characterized for the phase change random access memory (PCRAM) application. Planar-type PCRAM devices are fabricated with a TiN or W bottom electrode (BE). The crystallization behavior is characterized by applying an electrical pulse train and analyzed by applying the Johnson-Mehl-Avrami kinetics model.

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The aim of this study was to assess pharyngeal swallowing impairments in thyroidectomy patients and to delineate the contributory kinematic components. Forty consecutive patients (mean age = 47.33 years) and fourteen age- and sex-matched heathy adult volunteers (mean age = 42.

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