Background: Data on antimicrobial use at the national level is crucial to establish domestic antimicrobial stewardship policies and enable medical institutions to benchmark against each other. This study aimed to analyze antimicrobial use in Korean hospitals. Methods: We investigated the antimicrobials prescribed in Korean hospitals between 2018 and 2021, using data from the Health Insurance Review and Assessment. Primary care hospitals (PCHs), secondary care hospitals (SCHs), and tertiary care hospitals (TCHs) were included in this analysis. Antimicrobials were categorized according to the Korea National Antimicrobial Use Analysis System (KONAS) classification, which is suitable for measuring antimicrobial use in Korean hospitals. Results: Out of more than 1,900 hospitals, PCHs and TCHs represented the largest and lowest percentage of hospitals, respectively. The most frequently prescribed antimicrobial in 2021 was piperacillin/β-lactamase inhibitor (9.3%) in TCHs, ceftriaxone (11.0%) in SCHs, and cefazedone (18.9%) in PCHs. Between 2018 and 2021, the most used antimicrobial class according to the KONAS classification was ‘broad-spectrum antibacterial agents predominantly used for community-acquired infections’ in TCHs and SCHs, and 'narrow spectrum beta-lactam agents' in PCH. Total consumption of antimicrobials has decreased from 951.7 to 929.9 days of therapy (DOT)/1,000 patient-days in TCHs and from 817.8 to 752.2 DOT/1,000 patient-days in SCHs during study period, but not in PCHs (from 504.3 to 527.2 DOT/1,000 patient-days). Moreover, in 2021, while use of reserve antimicrobials has decreased from 13.6 to 10.7 DOT/1,000 patient-days in TCHs and from 4.6 to 3.3 DOT/1,000 patient-days in SCHs, it has increased from 0.7 to 0.8 DOT/1,000 patient-days in PCHs. Conclusion: This study confirms that antimicrobial use differs by hospital type in Korea. Recent increases of use of antimicrobials, including reserve antimicrobials, in PCHs reflect the challenges that must be addressed.

Oxidative stress causes several diseases and dysfunctions in cells, including oocytes. Clearly, oxidative stress influences oocyte quality during in vitro maturation and fertilization. Here we tested the ability of coenzyme Q10 (CoQ10) to reduce reactive oxygen species (ROS) and improve mouse oocyte quality during in vitro culture. Treatment with 50 μM CoQ10 efficiently reduced ROS levels in oocytes cultured in vitro. The fertilizable form of an oocyte usually contains a cortical granule-free domain (CGFD). CoQ10 enhanced the ratio of CGFD–oocytes from 35% to 45%. However, the hardening of the zona pellucida in oocytes was not affected by CoQ10 treatment. The in vitro maturation capacity of oocytes, which was determined by the first polar body extrusion, was enhanced from 48.9% to 75.7% by the addition of CoQ10 to the culture medium. During the parthenogenesis process, the number of two-cell embryos was increased by CoQ10 from 43.5% to 67.3%. Additionally, treatment with CoQ10 increased the expression of Bcl2 and Sirt1 in cumulus cells. These results suggested that CoQ10 had a positive effect on ROS reduction, maturation rate and two-cell embryo formation in mouse oocyte culture.

A new species of chionelasmatid sessile vent barnacle, Eochionelasmus coreana sp. nov., is described and illustrated on the basis of specimens collected from the Solitaire hydrothermal vent field in the Central Indian Ridge of the Indian Ocean. This new species is morphologically very similar to E. ohtai, the type species of the genus Eochionelasmus. However, it differs from E. ohtai in its distribution, the status of the notch on the maxillule, and the positions of rl1 and cl1 on whorls of the imbricating plates. In addition, a molecular phylogenetic tree indicated that the chionelasmatid Eochionelasmus was closely related to the waikalasmatid Waikalasma with high supporting values rather than the other chionelasmatid Chionelasmus. The new species is not only the first record of a sessile vent barnacle from outside of the Pacific Ocean, but is also the first sessile barnacle from the Indian Ocean.

We investigated the pressure dependence of the inductive coupled plasma (ICP) oxidation on the electrical characteristics of the thin oxide films. Activation energies and electron temperatures with different pressures were estimated. To demonstrate the pressure effect on the plasma oxide quality, simple N type metal-oxide-semiconductor (NMOS) transistors were fabricated and investigated in a few electrical properties. At higher pressure than 200mTorr, plasma oxide has a slightly higher on-current and a lower interfacial trap density. The on-current gain seems to be related to the field mobility increase and the lower defective interface to the electron temperature during oxidation.

Electron tomography and high-resolution transmission electron microscopy were used to characterize the unique 3-dimensional (3D) structures of twinned Zn3P2 (tetragonal) and InAs (zinc blende) nanowires synthesized by the vapor transport method. The Zn3P2 nanowires adopt a unique superlattice structure that consists of twinned octahedral slice segments having alternating orientations along the axial [111] direction of a pseudocubic unit cell. The apices of the octahedral slice segment are indexed as six equivalent <112> directions at the [111] zone axis. At each 30 degrees turn, the straight and zigzagged morphologies appear repeatedly at the <112> and <011> zone axes, respectively. The 3D structure of the twinned Zn3P2 nanowires is virtually the same as that of the twinned InAs nanowires. In addition, we analyzed the 3D structure of zigzagged CdO (rock salt) nanowires and found that they include hexahedral segments, whose six apices are matched to the <011> directions, linked along the [111] axial direction. We also analyzed the unique 3D structure of rutile TiO2 (tetragonal) nanobelts; at each 90 degree turn, the straight morphology appears repeatedly, while the in-between twisted form appears at the [011] zone axis. We suggest that the TiO2 nanobelts consist of twinned octahedral slices whose six apices are indexed by the <011>/<001> directions with the axial [010] direction.

By injecting additional argon gas, we were able to grow one-dimensional ZnO nanorod arrays with a uniform distribution on a large scale at a low temperature of less than 330 °C by metalorganic chemical vapor deposition. All of the nanorods grown on the sapphire substrate had a 30° in-plane rotation with respect to the substrate and showed the epitaxial characteristics of [10¯10]ZnO//[11¯20]sapphire, despite the low-temperature growth. These ZnO nanorods with high crystalline quality exhibited a high enhancement factor and low turn-on field value, thus having good potential to be used as a field emitter.

Bump process using gold bump led to many cleaning problems like polymer residues, metal and polyimide consumption after stripping process. First of all, stripping process of bump photoresist is one of the difficult technologies since thickness of PR pattern of bump is thicker than that of general metal line at least 100 times. We investigated the improvement of LDI BUMP stripping Process at 25 with new chemical. We found that the wettability may be improved when the additive was added to the chemical and it improves the stripping ability. It was found that new chemical was superior to commercial chemical in terms of chemical stability, removal efficiency of polymer residue and decrease in metal and polyimide consumption. Also, we could obtain removal mechanism of photoresist pattern by measured Raman equipment and enhancement of yield in mass production line of semiconductor.

A gradual change in thermal oxide surface state from hydrophilic to hydrophobic was observed with time -delay in a clean room environment. Surface quality and reflectivity for the Al/Ti metal layers showed a strong dependency on the oxide surface state. From the hydrophilic oxide substrate, a lower (002) Ti preferred orientation was obtained than from hydrophobic ones. This resulted in a degraded (111) Al preferred orientation and rough metal surface. The RF-etch process increased the smoothness and hydrophobic surface property for the inter -metal dielectric (IMD) oxides, and therefore greatly improved Al/Ti surface quality. When conventional CMOS double layer metal interconnection process is performed, metal inter-line bridge yield was strongly affected by the surface state of substrate oxides.

An aluminum thin film for ultra large scale integrated circuits(ULSI) metalization has been formed by PACVD using DMEAA(Dimethylethylamine alane) as a precursor. The selectivity was lost but the conformal step coverage was still maintained when the hydrogen plasma was added to conventional CVD process so that perfectly planarized metalization could be obtained.

Comparing to thermal CVD, the reflectivity as well as the resistivity could be much improved especially when the film was deposited on SiO2. The deposition rate and the resistivity of PACVD Al thin films deposited on various substrates such as Si, TiN and SiO2 were compared with those of thermal CVD Al thin films.

The formation of BaCeO3 and its effects on microstructure were studied in sintered/melt-textured Y-Ba-Cu-O oxides containing 5 wt. % CeO2 and various amounts of Y2Ba1Cu1O5. The added CeO2 was converted to fine particles of BaCeO3 near 930 °C, which is the conventional sintering temperature for Y-Ba–Cu-O. Y2Ba1Cu1O5 and CuO are formed as by-products of the reaction between CeO2 and Y1Ba2Cu3O7−y phase. The CeO2 addition reduced the particle size of Y2Ba1Cu1O5 which was trapped in the Y1Ba2Cu3O7−y matrix after the melt-texture growth. During the peritectic decomposition stage of Y1Ba2Cu3O7−y phase into Y2Ba1Cu1O5 and liquid phase, the morphology of the decomposed Y2Ba1Cu1O5 was changed from a blocky shape in the undoped sample to an acicular shape of high anisotropy in the CeO2-added sample. The formation of the highly anisotropic Y2Ba1Cu1O5 particles appears to be responsible for the refinement of Y2Ba1Cu1O5 particle after the melt-texture processing.

In order to investigate microstructural variation by 2-1-1 addition in partially melted Y–Ba–Cu–O, a specimen resulting from 2-1-1 added to 1-2-3 was heat-treated through the peritectic temperature. Microstructure was observed on the directionally solidified region near the interface of the two samples. The 2-1-1 addition results in a homogeneous microstructure where no remnant liquid phase is present. It reduced the 1-2-3 plate thickness, as well as suppressed the formation of microcracks due to the tetragonal-to-orthorhombic phase transition or the thermal contraction during cooling from the peritectic temperature. The formation of microcracks induced by the phase transition seems to be closely related to the process of oxygen diffusion into a sample. We discuss the formation of microcracks in terms of the oxygen diffusion along the plate boundaries and of the thickness of 1-2-3 plates. The decrease in the plate thickness and the fine dispersion of 2-1-1 particles contribute suppression of the formation of microcracks and their propagation.

The hydrogenation effect was studied in the fabrication of amorphous silicon thin film transistor using APCVD technique. The inverse staggered type a-Si TFTs were fabricated with the deposited a-Si and SiO2 films by the atmospheric pressure (AP) CVD. The field effect mobility of the fabricated a-Si TFT is 0.79 cm2/Vs and threshold voltage is 5.4V after post hydrogenation. These results can be applied to make low cost a-Si TFT array using an in-line APCVD system.

The CeO2-added Y–Ba–Cu–O oxides were prepared by two different processes, the conventional solid-state reaction process and the partial melt process using powders, to examine the effect of the dopant on microstructure, microhardness, and superconductivity. In the solid-state reacted sample, most of the added CeO2 was converted to a form of BaCeO3, but some might enter into the 1-2-3 phase, resulting in the orthorhombic-to-tetragonal phase transition that accompanied the disappearance of twin structure in 1-2-3 grains. In the partially melted sample, however, the phase change was not observed up to 5 wt. % of CeO2. All the added CeO2 in these samples was consumed to form only BaCeO3 which was finely dispersed in large 1-2-3 grains during the peritectic reaction stage. The zero resistance temperature (Tc) of the solid-state reacted sample gradually decreased with increasing CeO2 content due to the phase change and the formation of BaCeO3, whereas the Tc of the partially melted sample was nearly constant regardless of CeO2 content up to 5 wt. %, owing to the separation of the second phase from the 1-2-3 superconducting phase. Microhardness of the partially melted sample increased with increasing CeO2 content. The strengthening effect appears to come from the composite system where the fine BaCeO3 particles are dispersed in a 1-2-3 matrix.