Publications by authors named "Hyunjin Jung"

Excitons in semiconductors and molecules are widely utilized in photovoltaics and optoelectronics, and high-temperature coherent quantum states of excitons can be realized in artificial electron-hole bilayers and an exotic material of an excitonic insulator (EI). Here, we investigate the band gap evolution of a putative high-temperature EI TaNiSe upon surface doing by alkali adsorbates with angle-resolved photoemission and density functional theory (DFT) calculations. The conduction band of TaNiSe is filled by the charge transfer from alkali adsorbates, and the band gap decreases drastically upon the increase of metallic electron density.

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Adsorption of alkali atoms onto material surfaces is widely utilized for controlling electronic properties and is particularly effective for two-dimensional materials. While tuning the chemical potential and band gap and creating quantum-confined states are well established for alkali adsorption on semiconductors, the effects on semimetallic systems remain largely elusive. Here, utilizing angle-resolved photoemission spectroscopy measurements and density functional theory calculations, we disclose the creation of two-dimensional electron gas and the quantum-confined Lifshitz transition at the surface of a Weyl semimetal -MoTe by potassium adsorption.

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Background: While Programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) blockade is a potent antitumor treatment strategy, it is effective in only limited subsets of patients with cancer, emphasizing the need for the identification of additional immune checkpoints. Butyrophilin 1A1 (BTN1A1) has been reported to exhibit potential immunoregulatory activity, but its ability to function as an immune checkpoint remains to be systematically assessed, and the mechanisms underlying such activity have yet to be characterized.

Methods: BTN1A1 expression was evaluated in primary tumor tissue samples, and its ability to suppress T-cell activation and T cell-dependent tumor clearance was examined.

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Recently discovered Higgs particle is a key element in the standard model of elementary particles and its analogue in materials, massive Higgs mode, has elucidated intriguing collective phenomena in a wide range of materials with spontaneous symmetry breaking such as antiferromagnets, cold atoms, superconductors, superfluids, and charge density waves (CDW). As a straightforward extension beyond the standard model, multiple Higgs particles have been considered theoretically but not yet for Higgs modes. Here, we report the real-space observations, which suggest two Higgs modes coupled together with a soliton lattice in a solid.

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We report on the Tomonaga-Luttinger liquid (TLL) behavior in fully degenerate 1D Dirac Fermions. A ternary van der Waals material NbSiTe incorporates in-plane NbTe chains, which produce a 1D Dirac band crossing Fermi energy. Tunneling conductance of electrons confined within NbTe chains is found to be substantially suppressed at Fermi energy, which follows a power law with a universal temperature scaling, hallmarking a TLL state.

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High electrochemical polarization during a redox reaction in the electrode of aqueous zinc-bromine flow batteries largely limits its practical implementation as an effective energy storage system. This study demonstrates a rationally-designed composite electrode that exhibits a lower electrochemical polarization by providing a higher number of catalytically-active sites for faster bromine reaction, compared to a conventional graphite felt cathode. The composite electrode is composed of electrically-conductive graphite felt (GF) and highly active mesoporous tungsten oxynitride nanofibers (mWONNFs) that are prepared by electrospinning and simple heat treatments.

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This paper describes the fabrication of cicada-wing-inspired antimicrobial surfaces using Glancing Angle Deposition (GLAD). From the study of an annual cicada (Neotibicen Canicularis, also known as dog-day cicada) in North America, it is found that the cicada wing surfaces are composed of unique three-dimensional (3D) nanofeature arrays, which grant them extraordinary properties including antimicrobial (antifouling) and antireflective. However, the morphology of these 3D nanostructures imposes challenges in artificially synthesizing the structures by utilizing and scaling up the template area from nature.

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The reversibly stable formation and rupture processes of electrical percolative pathways in organic and inorganic insulating materials are essential prerequisites for operating non-volatile resistive memory devices. However, such resistive switching has not yet been reported for dynamically cross-linked polymers capable of intrinsic stretchability and self-healing. This is attributable to the uncontrollable interplay between the conducting filler and the polymer.

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Soft biomimetic electronic devices primarily comprise an electronic skin (e-skin) capable of implementing various wearable/implantable applications such as soft human-machine interfaces, epidermal healthcare systems, and neuroprosthetics owing to its high mechanical flexibility, tissue conformability, and multifunctionality. The conformal contact of the e-skin with living tissues enables more precise analyses of physiological signals, even in the long term, as compared to rigid electronic devices. In this regard, e-skin can be considered as a promising formfactor for developing highly sensitive and transparent pressure sensors.

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Although skin-like pressure sensors exhibit high sensitivity with a high performance over a wide area, they have limitations owing to the critical issue of being linear only in a narrow strain range. Various strategies have been proposed to improve the performance of soft pressure sensors, but such a nonlinearity issue still exists and the sensors are only effective within a very narrow strain range. Herein, we fabricated a highly sensitive multi-channel pressure sensor array by using a simple thermal evaporation process of conducting nanomembranes onto a stretchable substrate.

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Neuronal morphogenesis requires multiple regulatory pathways to appropriately determine axonal and dendritic structures, thereby to enable the functional neural connectivity. Yet, however, the precise mechanisms and components that regulate neuronal morphogenesis are still largely unknown. Here, we newly identified the sequential phosphorylation of NDEL1 critical for neuronal morphogenesis through the human kinome screening and phospho-proteomics analysis of NDEL1 from mouse brain lysate.

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Actin waves are filamentous actin (F-actin)-rich structures that initiate in the somato-neuritic area and move toward neurite ends. The upstream cues that initiate actin waves are poorly understood. Here, using an optogenetic approach (Opto-cytTrkB), we found that local activation of the TrkB receptor around the neurite end initiates actin waves and triggers neurite elongation.

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Intracellular antibodies have become powerful tools for imaging, modulating and neutralizing endogenous target proteins. Here, we describe an optogenetically activated intracellular antibody (optobody) consisting of split antibody fragments and blue-light inducible heterodimerization domains. We expanded this optobody platform by generating several optobodies from previously developed intracellular antibodies, and demonstrated that photoactivation of gelsolin and β2-adrenergic receptor (β2AR) optobodies suppressed endogenous gelsolin activity and β2AR signaling, respectively.

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Spatiotemporal control of gene expression or labeling is a valuable strategy for identifying functions of genes within complex neural circuits. Here, we develop a highly light-sensitive and efficient photoactivatable Flp recombinase (PA-Flp) that is suitable for genetic manipulation in vivo. The highly light-sensitive property of PA-Flp is ideal for activation in deep mouse brain regions by illumination with a noninvasive light-emitting diode.

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Layered rare-earth hydroxides (LRHs) with high anion exchangeability between the hydroxocation layers, where a large variety of organic anions can be sheltered, are employed to construct hybrid systems that slowly release active organic ingredients. More importantly, it is possible to endow LRHs with a photoluminescence capability by doping activator ions such as Ce, Eu, and Tb into matrices. In the present work, we explored Tb-doped layered yttrium hydroxide YTb(OH)Cl· nHO (LYH:Tb) nanosheets as a luminescent carrier for sustained release of salicylic acid (2-hydroxybenzoic acid), an example of nonsteroidal anti-inflammatory drugs and antimicrobial agents.

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Purpose: The study was designed to assess and predict patient-reported goal achievement after treatment of benign prostatic hyperplasia (BPH) patients with tamsulosin.

Materials And Methods: From November 2013 to October 2015, 272 patients initially diagnosed with BPH were prospectively enrolled in nine different centers. Before the treatment, subjective final goals were recorded by all patients.

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Although dissociative identity disorder (DID), the most severe of the dissociative disorders, has retained its own diagnostic entity since its introduction in the DSM-III, cases of DID are rarely seen in South and East Asia, likely due to the higher prevalence of possession disorder. We report two patients with DID who were recently admitted to our inpatient psychiatric unit and demonstrated distinct transitions to several identities. Their diagnoses were confirmed through a structured interview for dissociative disorders and possible differential diagnoses were ruled out by psychological, neuroimaging, and laboratory tests.

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Indications of sutureless repair (SR) for pulmonary vein anomalies have evolved from re-operational SR for pulmonary vein stenosis after the repair of total anomalous pulmonary venous drainage (TAPVD) to primary SR for TAPVD associated with right atrial isomerism or isolated TAPVD with small individual pulmonary veins (IPVs) and an unfavorable pulmonary vein anatomy. We sought to determine whether small IPVs outgrow somatic growth after primary SR. Between 2004 and 2013, 21 children underwent primary SR for TAPVD: 13 with a functionally single ventricle, 11 with right atrial isomerism, six with isolated TAPVD, and 13 with a pulmonary venous obstruction.

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Purpose: It has been reported that varicocele is found less frequently in obese men. Accordingly, we evaluated varicocele patients and statistically analyzed the correlation between varicocele and somatometric parameters.

Materials And Methods: A total of 211 patients underwent surgery for varicoceles.

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A large set of Bacillus megaterium CYP102A1 mutants are known to metabolize various drugs to form human metabolites. Omeprazole (OMP), a proton pump inhibitor, has been widely used as an acid inhibitory agent for the treatment of gastric acid hypersecretion disorders. It is primarily metabolized by human CYP2C19 and CYP3A4 to 5'-OH OMP and a sulfone product, respectively.

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Receptor tyrosine kinases (RTKs) are a family of cell-surface receptors that have a key role in regulating critical cellular processes. Here, to understand and precisely control RTK signalling, we report the development of a genetically encoded, photoactivatable Trk (tropomyosin-related kinase) family of RTKs using a light-responsive module based on Arabidopsis thaliana cryptochrome 2. Blue-light stimulation (488 nm) of mammalian cells harbouring these receptors robustly upregulates canonical Trk signalling.

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Objectives: To assess the effectiveness of a comprehensive workplace stress management program consisting of participatory action-oriented training (PAOT) and individual management.

Methods: A comprehensive workplace stress management program was conducted in a medium-sized enterprise. The baseline survey was conducted in September 2011, using the Korean Occupational Stress Scale (KOSS) and Worker's Stress Response Inventory (WSRI).

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A method of steroid profiling, including androgens, progestins, corticoids and sterols, was developed to evaluate the concentrations of steroids as well as the activities of the enzymes responsible for steroidogenesis in hair by gas chromatography/mass spectrometry. The extraction efficiencies of steroids from the hair matrix were improved by ultrasonication for 1 h at 50 °C. The overall recoveries ranged from 71 to 132%, with a limit of quantification for all analytes ranging from 1 to 50 ng/g.

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Background: A database-dependent gas chromatography-mass spectrometry (GC-MS) based approach was developed for non-targeted metabolite profiling, focusing on 232 steroids, 24 fatty acids, 10 eicosanoids, 10 cannabinoids and 22 steroid-fatty acid esters in biological specimens.

Methods: This method, used to search for potent biomarkers in lipid metabolism, included MS based analysis combined with high-temperature gas chromatographic (HTGC) separation of biological metabolites, statistical clustering and an in-house database (DB) searching.

Results: The HTGC technique showed better detectability of high lipophilic compounds, particularly steroid-fatty acid esters, which generally have poor chromatographic properties on a conventional GC column.

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