Publications by authors named "Jun Kyu Kim"

In this study, we identify the local structures of ex-solved nanoparticles using machine-learned potentials (MLPs). We develop a method for training machine-learned potentials by sampling local structures of heterointerface configurations as a training set with its efficacy tested on the Ni/MgO system, illustrating that the error in interface energy is only 0.004 eV/Å.

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Deformable semi-solid liquid metal particles (LMP) have emerged as a promising substitute for rigid conductive fillers due to their excellent electrical properties and stable conductance under strain. However, achieving a compact and robust coating of LMP on fibers remains a persistent challenge, mainly due to the incompatibility of conventional coating techniques with LMP. Additionally, the limited durability and absence of initial electrical conductivity of LMP restrict their widespread application.

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Ex-solution catalysts containing spontaneously formed metal nanoparticles socketed on the surface of reservoir oxides have recently been employed in various research fields including catalysis and sensing, due to the process efficiency and outstanding chemical/thermal stability. However, since the ex-solution process accompanies harsh reduction heat treatment, during which many oxides undergo phase decomposition, it restricts material selection and further advancement. Herein, we propose an elaborate design principle to uniformly functionalize ex-solution catalysts at porous oxide frameworks via an electrospinning process.

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The combination of supported metal nanoparticles and functional host oxides catalyze many major industrial reactions. However, uniform dispersion and ideal chemical configuration of such nanoparticles, which determines the catalytic activity, are often difficult to achieve. In this study, a unique combination is proposed of heterogeneous doping and ex-solution for the fabrication of Pt-Ni alloy nanoparticles on CeO .

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Metal oxides possessing distinctive physical/chemical properties due to different crystal structures and stoichiometries play a pivotal role in numerous current technologies, especially heterogeneous catalysis for production/conversion of high-valued chemicals and energy. To date, many researchers have investigated the effect of the structure and composition of these materials on their reactivity to various chemical and electrochemical reactions. However, metal oxide surfaces evolve from their initial form under dynamic reaction conditions due to the autonomous behaviors of the constituent atoms to adapt to the surrounding environment.

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Ex-solution catalysts, in which a host oxide is decorated with confined metallic nanoparticles, have exhibited breakthrough activity in various catalytic reactions. However, catalysts prepared by conventional ex-solution processes are limited by the low surface area of host oxides, the limited solubility of dopants, and the incomplete conversion of doped cations into metal catalysts. Here, the design of the host oxide structure is reconceptualized using a metal-organic framework (MOF) as an oxide precursor that can absorb a large quantity of ions while also promoting ex-solution at low temperatures (400-500 °C).

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Extracellular vesicles (EVs) are membrane-derived heterogeneous vesicles that mediate intercellular communications. They have recently been considered as ideal vehicles for drug-delivery systems, and immune cells are suggested as a potential source for drug-loaded EVs. In this study, we investigated the possibility of neutrophils as a source for drug-loaded EVs.

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Extracellular vesicles (EVs) are membrane-derived vesicles that mediate intercellular communications. Neutrophils produce different subtypes of EVs during inflammatory responses. Neutrophil-derived trails (NDTRs) are generated by neutrophils migrating toward inflammatory foci, whereas neutrophil-derived microvesicles (NDMVs) are thought to be generated by neutrophils that have arrived at the inflammatory foci.

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Supported metal catalysts represent one of the major milestones in heterogeneous catalysis. Such catalytic systems are feasible for use in a broad range of applications, including renewable energy devices, sensors, automotive emission control systems, and chemical reformers. The lifetimes of these catalytic platforms depend strongly on the stability of the supported nanoparticles.

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The ex-solution phenomenon, a central platform for growing metal nanoparticles on the surface of host oxides in real time with high durability and a fine distribution, has recently been applied to various scientific and industrial fields, such as catalysis, sensing, and renewable energy. However, the high-temperature processing required for ex-solutions (>700 °C) limits the applicable material compositions and has hindered advances in this technique. Here, an unprecedented approach is reported for low-temperature particle ex-solution on important nanoscale binary oxides.

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The ex-solution process, in which metal nanoparticles are grown on a host oxide, can be used to synthesize nanocatalysts with excellent thermal and chemical durability via spontaneous heterogeneous nucleation. However, this technique lacks a means to control the particle size and density because the amounts of ex-solved metal elements vary with the reduction conditions. Here, we devise a strategy to achieve small particle sizes and high particle densities concurrently by controlling the temperature (), oxygen partial pressure () and ramping rate of the temperature.

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A precise control of the size, density, and distribution of metal nanoparticles dispersed on functional oxide supports is critical for promoting catalytic activity and stability in renewable energy and catalysis devices. Here, we measure the growth kinetics of individual Co particles ex-solved on SrTiCoO polycrystalline thin films under a high vacuum, and at various temperatures and grain sizes using in situ transmission electron microscopy. The ex-solution preferentially occurs at grain boundaries and corners which appear essential for controlling particle density and distribution, and enabling low temperature ex-solution.

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Supported metal nanoparticles hold great promise for many fields, including catalysis and renewable energy. Here we report a novel methodology for the in situ growth of architecturally tailored, regenerative metal nanocatalysts that is applicable to a wide range of materials. The main idea underlying this strategy is to selectively diffuse catalytically active metals along the grain boundaries of host oxides and then to reduce the diffused metallic species to form nanoclusters.

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The data presented in this article are related to the research article entitled "Retinoic acid induces hypersegmentation and enhances cytotoxicity of neutrophils against cancer cells" (S. Shrestha, S.Y.

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Rationale: Neutrophils are key effectors in the host's immune response to sepsis. Excessive stimulation or dysregulated neutrophil functions are believed to be responsible for sepsis pathogenesis. However, the mechanisms regulating functional plasticity of neutrophils during sepsis have not been fully determined.

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Hypersegmentation of nuclei is considered a distinct characteristic of the antitumoral phenotype of neutrophils. Retinoic acid, a metabolite of retinol, reorganizes and induces segmentation of the nucleus during the differentiation of neutrophils. However, the role of retinoic acid in the phenotype polarization of neutrophils has not been fully established.

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Objectives: Korean red ginseng (KRG) has hypoglycemic, antioxidant, antithrombotic, and other beneficial effects in human. The present study evaluate the therapeutic effects of KRG on hearing recovery and glucocorticoid-induced hyperglycemia in patients with idiopathic sudden sensorineural hearing loss (SSNHL) undergoing systemic steroid therapy.

Methods: The patients were divided into 2 groups: the steroid, and the combination of steroid and red ginseng.

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Conclusion: Intratympanic steroid therapy (IT-S) was as effective as systemic steroid therapy (SST) or combined therapy (CT) and could be considered a first-line therapeutic modality for idiopathic sudden sensorineural hearing loss (SSNHL). Due to its known safety and efficacy, IT-S will be particularly suitable for patients with SSNHL who have chronic diseases such as diabetes mellitus, hypertension, or chronic renal failure.

Objectives: Systemic high dose steroid therapy is the main therapeutic modality for SSNHL.

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Aminoamide local anesthetics induce vasoconstriction in vivo and in vitro. The goals of this in vitro study were to investigate the potency of local anesthetic-induced vasoconstriction and to identify the physicochemical property (octanol/buffer partition coefficient, pKa, molecular weight, or potency) of local anesthetics that determines their potency in inducing isolated rat aortic ring contraction. Cumulative concentration-response curves to local anesthetics (levobupivacaine, ropivacaine, lidocaine, and mepivacaine) were obtained from isolated rat aorta.

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To radiologically evaluate the anatomic factors that may determine the view field or the accessibility of the posterior tympanotomy into the posterior mesotympanum, a cohort of 30 patients with pneumatic mastoids and 30 patients with unilateral sclerotic mastoids were included. Anatomic relationships were evaluated according to 5 parameters. The reference parameter of the view field through posterior tympanotomy was the maximum view to the stapes area through posterior tympanotomy.

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