Publications by authors named "Jong Bo Park"

Podocyte injury and proteinuria in glomerular disease are critical indicators of acute kidney injury progression to chronic kidney disease. Renal mitochondrial dysfunction, mediated by intracellular calcium levels and oxidative stress, is a major contributor to podocyte complications. Despite various strategies targeting mitochondria to improve kidney function, effective treatments remain lacking.

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An aqueous two-phase system (ATPS) is a water-in-water biphasic system, which is generally formed by two incompatible polymers. Recently, considerable effort has been dedicated to search for new ATPS polymer pairs to further expand ATPS's applications. In this paper, a new ATPS system based on silk fibroin (SF) and alginate is introduced.

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Amorphous indium- gallium-zinc oxide (a-IGZO) has been intensively studied for the application to active matrix flat-panel display because of its superior electrical and optical properties. However, the characteristics of a-IGZO were found to be very sensitive to external circumstance such as light illumination, which dramatically degrades the device performance and stability practically required for display applications. Here, we suggest the use for silicon-germanium (Si-Ge) films grown plasma-enhanced chemical vapour deposition (PECVD) as photo-blocking layers in the a-IGZO thin film transistors (TFTs).

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Amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) have been under intense investigation as one of the promising candidates for active matrix flat-panel displays. However, solid diffusion of a-IGZO to other layers during TFT device fabrication highly degrades their electrical and optical properties. It is expected that the diffusion-impenetrable properties of graphitic materials can be utilized as diffusion barriers.

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Carbon electrodes including graphene and thin graphite films have been utilized for various energy and sensor applications, where the patterning of electrodes is essentially included. Laser scribing in a DVD writer and inkjet printing were used to pattern the graphene-like materials, but the size and speed of fabrication has been limited for practical applications. In this work, we devise a simple strategy to use conventional laser-printer toner materials as precursors for graphitic carbon electrodes.

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Bacterial biopolymers have drawn much attention owing to their unconventional three-dimensional structures and interesting functions, which are closely integrated with bacterial physiology. The nongenetic modulation of bacterial (Acetobacter xylinum) cellulose synthesis via nanocarbon hybridization, and its application to the emulation of layered neuronal tissue, is reported. The controlled dispersion of graphene oxide (GO) nanoflakes into bacterial cellulose (BC) culture media not only induces structural changes within a crystalline cellulose nanofibril, but also modulates their 3D collective association, leading to substantial reduction in Young's modulus (≈50%) and clear definition of water-hydrogel interfaces.

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Recently, smart contact lenses with electronic circuits have been proposed for various sensor and display applications where the use of flexible and biologically stable electrode materials is essential. Graphene is an atomically thin carbon material with a two-dimensional hexagonal lattice that shows outstanding electrical and mechanical properties as well as excellent biocompatibility. In addition, graphene is capable of protecting eyes from electromagnectic (EM) waves that may cause eye diseases such as cataracts.

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Two nanobubbles that merge in a graphene liquid cell take elliptical shapes rather than the ideal circular shapes. This phenomenon was investigated in detail by using in situ transmission electron microscopy (TEM). The results show that the distortion in the two-dimensional shapes of the merging nanobubbles is attributed to the anisotropic gas transport flux between the nanobubbles.

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We report an ultraclean, cost-effective, and easily scalable method of transferring and patterning large-area graphene using pressure sensitive adhesive films (PSAFs) at room temperature. This simple transfer is enabled by the difference in wettability and adhesion energy of graphene with respect to PSAF and a target substrate. The PSAF-transferred graphene is found to be free from residues and shows excellent charge carrier mobility as high as ∼17,700 cm(2)/V·s with less doping compared to the graphene transferred by thermal release tape (TRT) or poly(methyl methacrylate) (PMMA) as well as good uniformity over large areas.

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Formation, evolution and vanishing of bubbles are common phenomena in nature, which can be easily observed in boiling or falling water, carbonated drinks, gas-forming electrochemical reactions and so on. However, the morphology and the growth dynamics of the bubbles at nanoscale have not been fully investigated owing to the lack of proper imaging tools that can visualize nanoscale objects in the liquid phase. Here, we demonstrate for the first time that the nanobubbles in water encapsulated by graphene membrane can be visualized by in-situ ultra-high vacuum transmission electron microscopy.

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Silk fibroin/hydroxyapatite (SF/HAp) composite hydrogels were fabricated in this study, having different HAp contents (0-33 wt%) in SF matrix hydrogel. Surface modification of HAp nanoparticle with hyaluronic acid (HA)-dopamine (DA) conjugate improved a dispersibility of HAp in aqueous SF solution due to its negatively charged surface and therefore, fabrication of the SF composite hydrogel having HAp nanoparticles inside could be possible. Zeta potential of surface-modified HAP was examined by ELS.

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