Publications by authors named "Dae Hoon Park"

Particulate matter, including airborne pathogens, is of particular concern because it can cause the spread of diseases through aerosol transmission. In this study, a new concept is proposed: on-demand antiviral electrostatic precipitators (ESPs) with electrothermal-based antiviral surfaces. We applied electrothermal-based antiviral surfaces to air-purifying applications and demonstrated that the proposed method is effective with regard to collecting airborne virus particles on collection plates in a two-stage ESP.

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Air purification through fiber-based filters has become a fundamental requirement for air contamination control. However, conventional filters depend on polymeric fibrous filters with adequate particulate matter removal ability but fewer degassing and biocidal effects. This study presents the photocatalytic volatile organic compound (VOC) oxidation and antimicrobial properties of zinc oxide (ZnO) nano-spines sprouted activated-carbon nanofibers (I@ZnO/ACNFs) and their potential for air contamination control and infection prevention.

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Airborne virus susceptibility is an underlying cause of severe respiratory diseases, raising pandemic alerts worldwide. Following the first reports of the novel severe acute respiratory syndrome coronavirus-2 in 2019 and its rapid spread worldwide and the outbreak of a new highly variable strain of influenza A virus (H1N1) in 2009, developing quick, accurate monitoring and diagnostic approaches for emerging infections is considered critical. Efficient air sampling of coronaviruses and the H1N1 virus allows swift, real-time identification, triggering early adjuvant interventions.

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Recently, various studies have reported the prevention and treatment of respiratory infection outbreaks caused by lethal viruses. Consequently, a variety of air filters coated with antimicrobial agents have been developed to capture and inactivate virus particles in continuous airflow conditions. However, since aerosolized infectious viral-testing is inadvisable due to safety concerns, their anti-viral capability has only been tested by inserting the filters into liquid media, where infectious virus particles disperse.

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Article Synopsis
  • Cancer immunotherapies are being researched for their ability to enhance treatment effectiveness and reduce side effects compared to traditional cancer therapies.
  • This study introduces a new method using air-liquid two-phase electrospray to create biomimetic nanosystems made with clinically relevant compounds for better delivery of cancer drugs.
  • The developed nanosystems, specifically paclitaxel-loaded, show improved efficacy due to their unique shape, which enhances their transport and interaction with cells, outperforming similar-sized spherical particles with or without immunotherapy agents.
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Due to antimicrobial resistance and the adverse health effects that follow broad and inappropriate use of antibacterial agents, new classes of antibacterials with broad and strong bactericidal activity and safety for human use are urgently required globally, increasingly so with the onset of climate change. However, R&D in this field is known to be rarely profitable, unless a cost-effective, flexible, and convenient platform that ensures the production of workable candidate antibacterials can be developed. To address this issue, inorganic nanomaterials have been considered for their bactericidal activities, yet further investigations of composition crystalline modifications and/or surface biomaterial coatings are still required to provide effective and safe antibacterial nanoparticles.

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We report a simple method to realize multifunctional flexible motion sensor using ferroelectric lithium-doped ZnO-PDMS. The ferroelectric layer enables piezoelectric dynamic sensing and provides additional motion information to more precisely discriminate different motions. The PEDOT:PSS-functionalized AgNWs, working as electrode layers for the piezoelectric sensing layer, resistively detect a change of both movement or temperature.

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In this study, the effect of dust loading on the anti-viral ability of an anti-viral air filter was investigated. Silver nanoparticles approximately 11 nm in diameter were synthesized via a spark discharge generation system and were used as anti-viral agents coated onto a medium air filter. The pressure drop, filtration efficiency, and anti-viral ability of the filter against aerosolized bacteriophage MS2 virus particles were tested with dust loading.

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Bacteria can be inactivated through various physical and chemical means, and these have always been the focus of extensive research. To further improve the methodology for these ends, two types of plasma systems were investigated: nano-second pulsed plasma (NPP) as liquid discharge plasma and an Argon gas-feeding dielectric barrier discharge (Ar-DBD) as a form of surface plasma. To understand the sterilizing action of these two different plasma sources, we performed experiments with Staphylococcus aureus (S.

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Background: Photo-degradation of organic contaminants into non-hazardous mineral compounds is emerging as a strategy to purify water and environment. Tremendous research is being done using direct solar light for these purposes. In this paper we report on optimum conditions for complete mineralization of aqueous methyl orange using lab-prepared ZnO nanopowder catalyst under simulated solar light.

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Through this work, we have elucidated the mechanism of hydroxyl radicals (OH(•)) generation and its life time measurements in biosolution. We observed that plasma-initiated ultraviolet (UV) photolysis were responsible for the continues generation of OH(•) species, that resulted in OH(•) to be major reactive species (RS) in the solution. The density and lifetime of OH(•) species acted inversely proportional to each other with increasing depth inside the solution.

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In this work, we demonstrated the action of nanosecond pulsed plasma (NPP) on the generation of nitric oxide (NO) from the non-enzymatic pathway and on the modification of graphite oxide (GO) sheets to increase polymer solar cells (PSCs) efficiency. NO is an important signal and an effector molecule in animals, which is generated from the enzyme-catalyzed oxidation of L-arginine to NO and L-citrulline. Hence, L-arginine is an important biological precursor for NO formation.

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Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.

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We previously reported that interleukin (IL)-6 deficiency potentiates trimethyltin (TMT)-induced convulsive neurotoxicity. The purpose in this study was to investigate the molecular mechanism by which cytokines affect TMT-induced cognitive impairment. To accomplish this, we examined hippocampal changes in Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling in relation to cholinergic parameters after TMT treatment in mice genetically deficient in IL-6 (IL-6(-/-)), tumor necrosis factor-α (TNF-α(-/-)), or interferon-γ (IFN-γ(-/-)).

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A colloidal suspension of exfoliated, layered cobalt oxide nanosheets has been synthesized through the intercalation of quaternary tetramethylammonium ions into protonated lithium cobalt oxide. According to atomic force microscopy, exfoliated nanosheets of layered cobalt oxide show a plateau-like height profile with nanometer-level height, underscoring the formation of unilamellar 2D nanosheets. The exfoliation of layered cobalt oxide was cross-confirmed by X-ray diffraction, UV/Vis spectroscopy, and transmission electron microscopy.

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Mineralization of phenazopyridine, 1, in water, under solar-simulator radiation was efficiently achieved using nanoparticle CdS-sensitized rutile TiO(2), TiO(2)/CdS, 2, as photo-catalysts. Despite that, 2 showed two main drawbacks. Firstly, the system was difficult to recover by simple filtration, and demanded centrifugation.

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Sulfur-doped manganese oxide 1D nanostructures with controllable crystal structures and crystallite dimensions have been synthesized via one-pot non-hydrothermal solution route. Powder X-ray diffraction analysis clearly demonstrated that the crystal structures of the sulfur-doped manganates can be tailored by the change of reaction temperature; layered delta-MnO2-structured material was obtained at 60 degrees C while the reaction at 90 degrees C produced tunnel alpha-MnO2 structured material. According to field emission-scanning electron microscopy, both sulfur-doped manganates possess 1D nanostructure-type morphology with the diameter of approximately 20 nm and the length of approximately 1 microm for delta-MnO2-type material, and the diameter of approximately 100 nm and the length of approximately 800 nm for alpha-MnO2-type material, respectively.

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We have developed a direct nonhydrothermal route to nanostructured chalcogen-doped manganese oxides; K(x)MnO(2)Q(y) (Q = S, Se, and Te). According to combinative diffraction and microscopic analyses, the S- and Se-doped manganese oxides exhibit 1D nanowire-type morphology with layered delta-MnO(2)- and alpha-MnO(2)-structures, respectively, whereas the Te-doped compound consists of 3D nanospheres that are amorphous according to X-ray diffraction. X-ray absorption and X-ray photoelectron spectroscopy analyses clearly demonstrate that the doped chalcogen ions exist in the form of hexavalent chalcogenate clusters mainly on the sample surface or grain boundary.

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We have tried to control the aspect ratio and physicochemical properties of 1D nanostructured manganese oxides through copper doping. Copper-doped manganese oxide nanostructures have been synthesized by one-pot hydrothermal treatment for the mixed solution of permanganate anions and copper cations. According to powder X-ray diffraction and electron microscopic analyses, all the present materials commonly crystallize with alpha-MnO2-type structure but their aspect ratio decreases significantly with increasing the content of copper.

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We have investigated the effect of alkaline earth metal substitution on the crystal structure and physical properties of magnetic superconductors RuSr(1.9)A(0.1)GdCu(2)O(8) (A = Ca, Sr, and Ba) in order to probe an interaction between the magnetic coupling of the RuO(2) layer and the superconductivity of the CuO(2) layer.

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We have investigated systematically the effects of La substitution on the chemical bonding nature and physical properties of magnetic RuSr(2-x)La(x)GdCu2O8 superconductors. X-ray diffraction and energy dispersive spectroscopic microprobe analyses reveal that a fraction of Sr ions can be successfully replaced by La ions with the contraction of unit cell volume. According to electrical resistance and dc magnetization measurements, the La substitution gives rise to a significant reduction of superconducting transition temperature (T(c)) but to an increase of magnetic ordering temperature with depressed remanent magnetization.

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