Publications by authors named "Jee Eun Yang"

This study optimizes V and ΔV in amorphous indium-gallium-zinc-oxide (a-IGZO) field-effect transistors (FETs) by examining the influence of both channel length (L) and Ga composition. It was observed that as the ratio of In: Ga: Zn changed from 1:1:1 to 0.307:0.

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Facile phase transitions and electrical degradation of amorphous oxide semiconductors due to a high thermal budget have significantly limited their dynamic random-access memory (DRAM) applications, which require high thermal stability at temperatures over 600 °C. In this paper, we report an amorphous In-Sn-Ga-O (ITGO) semiconductor fabricated via atomic layer deposition, which exhibits high-temperature (∼700 °C) phase stability with moderate electrical properties. The optimal Sn-rich ITGO composition (In/Sn/Ga = 25:58:17 at.

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Article Synopsis
  • The Royal Oji Complex (ROC) is being studied for its effectiveness on the skin of children aged 0 to 3 years old, using keratinocytes from this age group and focusing on natural ingredients.
  • The study measured the impact of different ROC concentrations (0.1, 1, and 10 ppm) on essential genes for skin health and hydration, such as HAS3, IVL, LOR, and CLD1, using advanced techniques like qRT-PCR and ELISA.
  • Results showed that ROC significantly boosted HAS3 gene expression, suggesting benefits for skin hydration, while other genes responded differently at varying concentrations, indicating ROC's complex influence on young children's skin health.
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Analog in-memory computing synaptic devices are widely studied for efficient implementation of deep learning. However, synaptic devices based on resistive memory have difficulties implementing on-chip training due to the lack of means to control the amount of resistance change and large device variations. To overcome these shortcomings, silicon complementary metal-oxide semiconductor (Si-CMOS) and capacitor-based charge storage synapses are proposed, but it is difficult to obtain sufficient retention time due to Si-CMOS leakage currents, resulting in a deterioration of training accuracy.

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Understanding the self-assembly process of amyloidogenic protein is valuable not only to find its pathological implication but also to prepare protein-based biomaterials. α-Synuclein (αS), a pathological component of Parkinson's disease, producing one-dimensional (1D) amyloid fibrils, has been employed to generate two-dimensional (2D) protein films by encouraging an alternative self-assembly process. At a high temperature of 50 °C, αS molecules self-assembled into 2D films instead of 1D amyloid fibrils, whereas the fibrils were the major product at 37 °C.

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Amyloidogenesis of α-synuclein (αS) is considered to be a pathological phenomenon related to Parkinson's disease (PD). As a key component to reveal the fibrillation mechanism and toxicity, we have investigated an oligomeric species of αS capable of exhibiting the unit-assembly process leading to accelerated amyloid fibril formation. These oligomers previously shown to exist in a meta-stable state with mostly disordered structure and unable to seed the fibrillation were converted to either temperature-sensitive self-associative oligomers or NaCl-induced non-fibrillating oligomeric species.

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(-)-Epigallocatechin gallate (EGCG), the major component of green tea, has been re-evaluated with α-synuclein (αS), a pathological constituent of Parkinson's disease, to elaborate its therapeutic value. EGCG has been demonstrated to not only induce the off-pathway 'compact' oligomers of αS as suggested previously, but also drastically enhance the amyloid fibril formation of αS. Considering that the EGCG-induced amyloid fibrils could be a product of on-pathway SDS-sensitive 'transient' oligomers, the polyphenol effect on the transient 'active' oligomers (AOs) was investigated.

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Functional graffiti of nanoparticles onto target surface is an important issue in the development of nanodevices. A general strategy has been introduced here to decorate chemically diverse substrates with gold nanoparticles (AuNPs) in the form of a close-packed single layer by using an omni-adhesive protein of α-synuclein (αS) as conjugated with the particles. Since the adsorption was highly sensitive to pH, the amino acid sequence of αS exposed from the conjugates and its conformationally disordered state capable of exhibiting structural plasticity are considered to be responsible for the single-layer coating over diverse surfaces.

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Robust polydiacetylene-based colorimetric sensing material has been developed with amyloid fibrils of α-synuclein in the presence of 10,12-pentacosadiynoic acid (PCDA) by taking advantage of the specific fatty acid interaction of α-synuclein and structural regularity of the self-assembled product of amyloid fibrils. PCDA facilitated not only self-oligomerization of α-synuclein but also its fibrillation into the fibrils with increased thickness. Upon UV irradiation, the PCDA-containing amyloid fibrils (AF-PCDAs) turned blue, which then became red following heat treatment.

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Mono[6-deoxy-6-(pentacosa-10,12-diynyl amidomethyl)]-β-cyclodextrin was successfully synthesized by reacting mono-6-amino-6-deoxy-β-cyclodextrin with N-hydroxysuccinimide ester of 10,12-pentacosadiynoic acid in DMF. The modified β-cyclodextrin self-assembled and aggregated to form a worm-like supramolecular structure, and the novel supramolecular aggregates were studied using 2D nuclear magnetic resonance spectroscopy, X-ray powder diffraction, thermogravimetry, and electron microscopy. Interestingly, the synthesized pentacosa-10,12-diynyl amidomethyl-β-cyclodextrin formed columnar type self-aggregates and it was clearly differentiated from cage-like structure of native β-cyclodextrin.

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Background/aims: The role of prostaglandin E2 (PGE2) in the modulation of cell growth is well established in colorectal cancer. The aim of this study was to elucidate the significance of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) down-regulation on the prognosis of hepatocellular carcinoma (HCC) patients.

Methods: The expression of 15-PGDH in HCC cell lines and resected HCC tissues was investigated, and the correlation between 15-PGDH expression and HCC cell-line proliferation and patient survival was explored.

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Background & Aims: The aim of this study was to re-evaluate the diagnostic performance of alpha-foetoprotein (AFP) as a surveillance test for hepatocellular carcinoma (HCC) in patients with hepatitis B virus-related chronic liver disease who were treated with entecavir (ETV).

Methods: Between January 2007 and August 2012, we analysed 373 treatment-naïve patients with HBV-related chronic hepatitis (n = 229) or cirrhosis (n = 144) who were candidates for surveillance test, and were treated with ETV (0.5 mg/day) for longer than 12 months.

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Bezoars are concretions of undigested material and are most often observed in the stomach. They can occur at any site in the gastrointestinal tract; however, duodenal localization is very rare. We report the case of a 71-year-old male who had undergone subtotal gastrectomy with gastroduodenostomy and experienced severe epigastric discomfort, abdominal pain, and vomiting for a few days.

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In this report, mutual effect of α-synuclein and GPX-1 is investigated to unveil their involvement in the PD pathogenesis in terms of cellular defense mechanism against oxidative stress. Biochemical and immunocytochemical studies showed that α-synuclein enhanced the GPX-1 activity with Kd of 17.3nM and the enzyme in turn markedly enhanced in vitro fibrillation of α-synuclein.

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Crohn's disease (CD) is a chronic inflammatory bowel disease of unknown etiology. Most patients with CD will eventually develop a stricturing or penetrating complication. Colonoscopic findings may predict the clinical course in patients with CD.

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Background: Lewy body in the substantia nigra is a cardinal pathological feature of Parkinson's disease. Despite enormous efforts, the cause-and-effect relationship between Lewy body formation and the disorder is yet to be explicitly unveiled.

Methodology/principal Findings: Here, we showed that radiating amyloid fibrils (RAFs) were instantly developed on the surface of synthetic lipid membranes from the β-sheet free oligomeric species of α-synuclein through a unit-assembly process.

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Heavily phosphorus-doped silicon nanowires (Si NWs) show intriguing transport phenomena at low temperature. As we decrease the temperature, the resistivity of the Si NWs initially decreases, like metals, and starts to increase logarithmically below a resistivity minimum temperature (T(min)), which is accompanied by (i) a zero-bias dip in the differential conductance and (ii) anisotropic negative magnetoresistance (MR), depending on the angle between the applied magnetic field and current flow. These results are associated with the impurity band conduction and electron scattering by the localized spins at phosphorus donor states.

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An ultrasensitive electrochemical immunosensor for a protein using a Ag (I)-cysteamine complex (Ag-Cys) as a label was fabricated. The low detection of a protein was based on the electrochemical stripping of Ag from the adsorbed Ag-Cys complex on the gold nanoparticles (AuNPs) conjugated human immunoglobulin G (anti-IgG) antibody (AuNPs-anti-IgG). The electrochemical immunosensor was fabricated by immobilizing anti-IgG antibody on a poly-5,2':5',2''-terthiophene-3'-carboxylic acid (polyTTCA) film grown on the glassy carbon electrode through the covalent bond formation between amine groups of anti-IgG and carboxylic acid groups of polyTTCA.

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Removal of β2-microglobulin (β2M) from the blood of patients suffering from kidney dysfunction is crucial to protect those individuals from getting the diseased state of dialysis-related amyloidosis. By harnessing the nucleation-dependent fibrillation process of amyloidogenesis, a β2M removal strategy has been proposed by preparing seed-conjugated polymer beads and assimilating soluble β2M to the fibrils on the surface at neutral pH. A novel peptide segment of β2M ranging from residue 58 to residue 67 (Lys-Asp-Trp-Ser-Phe-Tyr-Leu-Leu-Tyr-Tyr), which was capable of being fibrillated at neutral pH was isolated.

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Recently, integrated flexible devices based on silicon nanowires (Si-NWs) have received significant attention as high performance flexible devices. However, most previous assembly methods can generate only specifically-shaped devices and require unconventional facilities, which has been a major hurdle for industrial applications. Herein, we report a simple but very efficient method for assembling Si-NWs into virtually generally-shape patterns on flexible substrates using only conventional microfabrication facilities, allowing us to mass-produce highly flexible low-noise devices.

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We present a method for assembling silicon nanowires (Si-NWs) in virtually general shape patterns using only conventional microfabrication facilities. In this method, silicon nanowires were functionalized with amine groups and dispersed in deionized water. The functionalized Si-NWs exhibited positive surface charges in the suspensions, and they were selectively adsorbed and aligned onto negatively charged surface regions on solid substrates.

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We report the energy band-gap modulation of single-crystalline Si1-xGex (0 View Article and Find Full Text PDF