Publications by authors named "Kyung Ho Park"

The auditory brainstem response (ABR) is a noninvasive test that measures neural activity in response to auditory stimuli. Racial differences in head shape have provided strong evidence for specific normative data and accurate device calibration. International standards emphasize the need for standardized procedures and references.

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Pure-tone audiometry, using an audiometer, is the fundamental hearing test for diagnosing hearing loss. The requirements of the devices and the detailed process for calibrating the related equipment are described in international standards. However, traceable calibration and uncertainty evaluation processes are not widely accepted or applied to the qualification and maintenance of audiometric equipment.

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Article Synopsis
  • This study examines hearing thresholds to understand changes in the human auditory system across different ages, using both the ISO 7029 standard and new data from four countries.
  • The research compares average hearing threshold levels under similar conditions, focusing on frequency ranges from 125 Hz to 12,500 Hz.
  • Findings indicate that while most hearing threshold data align with ISO 7029, some deviations exist based on age and sex, highlighting the need for integrating international data in potential ISO 7029 revisions.
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Arabidopsis flowering is dependent on interactions between a component of the florigens FLOWERING LOCUS T (FT) and the basic leucine zipper (bZIP) transcription factor FD. These proteins form a complex that activates the genes required for flowering competence and integrates environmental cues, such as photoperiod and temperature. However, it remains largely unknown how FT and FD are regulated at the protein level.

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Article Synopsis
  • This study examines the importance of using international standards like ISO and IEC for conducting hearing tests, emphasizing their role in uniform design, calibration, and assessment of testing instruments and methods.
  • By following these standards, hearing tests can achieve greater accuracy, reliability, and consistency, fostering global data sharing and research collaboration.
  • However, challenges like equipment variability, slow updates to standards, and cultural differences can hinder the effectiveness of these protocols, suggesting a need for local adaptation to enhance their relevance while still aligning with global frameworks.
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Purpose: This study is to evaluate the duration of facial nerve enhancement in gadolinium-enhanced temporal bone MRI after the onset of acute facial palsy.

Methods: Gd-enhanced MRI imagines were examined in 13 patients with idiopathic acute facial palsy within 14 days after the onset. The degree of facial nerve function was measured according to the House-Brackmann (H-B) grading system at their first visit at outpatient clinic.

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Background: Most extramedullary plasmacytomas (EMPs) aresolitary and located in the head and neck region. They may also occur in the visceral parts of the body.

Objectives: Here, we report a case of oral EMP followed by neoplastic plasma cell metastasis to both kidneys in a neutered male Pomeranian.

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Introduction: This study aimed to determine the minimum required length of microimplants (MIs) to prevent excessive micromotion during MI healing that can lead to MI failure.

Methods: Hypothesizing that the implantation depth of MI in cancellous bone (ID) is the key to the control of micromotion during MI healing, we numerically investigated the minimum ID required to maintain MI micromotion to below the threshold (30 μm) that would threaten MI survival. Twenty MI and bone models were built using MIs of 4 lengths and bone specimens with 5 different cortical bone thicknesses to create ID in the 0.

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Electronic devices composed of semiconducting two-dimensional (2D) materials and ultrathin 2D metallic electrode materials, accompanying synergistic interactions and extraordinary properties, are becoming highly promising for future flexible and transparent electronic and optoelectronic device applications. Unlike devices with bulk metal electrode and 2D channel materials, devices with ultrathin 2D electrode and 2D channel are susceptible to chemical reactions in both channel and electrode surface due to the high surface to volume ratio of the 2D structures. However, so far, the effect of doping was primary concerned on the channel component, and there is lack of understanding in terms of how to modulate electrical properties of devices by engineering electrical properties of both the metallic electrode and the semiconducting channel.

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Electronic devices in highly integrated and miniaturized systems demand electromagnetic interference shielding within nanoscale dimensions. Although several ultrathin materials have been proposed, satisfying various requirements such as ultrathin thickness, optical transparency, flexibility, and proper shielding efficiency remains a challenge. Herein, we report an ultrahigh electromagnetic interference (EMI) SSE/ value (>10 dB cm/g) using a conductive CuS nanosheet with thickness less than 20 nm, which was synthesized at room temperature.

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Licochalcone H (LCH) is a phenolic compound synthetically derived from licochalcone C (LCC) that exerts anticancer activity. In this study, we investigated the anticancer activity of LCH in human skin cancer A375 and A431 cells. The 3-(4,5-dimethylthiazol- 2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell viability assay was used to evaluate the antiproliferative activity of LCH.

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The characteristics of traps between the AlGaN barrier and the GaN channel layer in a high-electron-mobility-transistors (HEMTs) were investigated. The interface traps at the AlGaN/GaN interface as well as the border traps were experimentally analyzed because the AlGaN barrier layer functions as a dielectric owing to its high dielectric constant. The interface trap density D and border trap density N were extracted from a long-channel field-effect transistor (FET), conventionally known as a FATFET structure, via frequency-dependent capacitance-voltage (C-V) and conductance-voltage (G-V) measurements.

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Contact engineering for monolayered transition metal dichalcogenides (TMDCs) is considered to be of fundamental challenge for realizing high-performance TMDCs-based (opto) electronic devices. Here, an innovative concept is established for a device configuration with metallic copper monosulfide (CuS) electrodes that induces sulfur vacancy healing in the monolayer molybdenum disulfide (MoS ) channel. Excess sulfur adatoms from the metallic CuS electrodes are donated to heal sulfur vacancy defects in MoS that surprisingly improve the overall performance of its devices.

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Atherosclerosis is the deposition of plaque in the main arteries. It is an inflammatory condition involving the accumulation of macrophages and various lipids (low-density lipoprotein [LDL] cholesterol, ceramide, S1P). Moreover, endothelial cells, macrophages, leukocytes, and smooth muscle cells are the major players in the atherogenic process.

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Unmanned Aerial Vehicles are expected to create enormous benefits to society, but there are safety concerns in recognizing faults at the vehicle's control component. Prior studies proposed various fault detection approaches leveraging heuristics-based rules and supervised learning-based models, but there were several drawbacks. The rule-based approaches required an engineer to update the rules on every type of fault, and the supervised learning-based approaches necessitated the acquisition of a finely-labeled training dataset.

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Whole-genome sequencing (WGS) is promising for the quality control of laboratory facilities for (MTB) strains. We describe the clinical and laboratory characteristics of false positive versus true positive MTB cultures based on WGS, which were experienced in a real clinical setting. Strain harvest and DNA extraction from seven isolates from pre-extensive drug-resistant (pre-XDR) TB patients transferred to the Korea University Ansan Hospital were performed, and epidemiologic links and clinical information, including the phenotypic drug susceptibility test (pDST), were investigated.

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The aim of this study was to estimate the total number and rate of chronic otitis media (COM) operations and cholesteatoma surgeries in South Korea, using a nationwide survey which analysed a 13-year trend (2006-2018). This study also analysed the trend of COM operations and cholesteatoma surgeries according to year, sex, and age using a nationwide population-based database, and the 13-year trend was analysed according to age groups. This study used nationwide data from the National Health Information Database (NHID), which is a government-affiliated agency under the Korean Ministry of Health and Welfare that supervises all medical activities in Korea.

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In this study, high electron mobility transistor (HEMT) device was used as an immuno biosensor to measure concentration of a stress hormone, cortisol, by using selective binding on cortisol monoclonal antibody (c-Mab). Also, the HEMT sensor was enhanced in its sensitivity through light illumination to generate photocurrent. The optical pumping could assist the biosensor to discriminate more detailed change, which could result in an increment of limit of detection (LOD) to 1.

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The time-of-flight (ToF) principle is a method used to measure distance and construct three-dimensional (3D) images by detecting the time or the phase difference between emitted and back-reflected optical flux. The ToF principle has been employed for various applications including light ranging and detection (LiDAR), machine vision and biomedical engineering; however, bulky system size and slow switching speed have hindered the widespread application of ToF technology. To alleviate these issues, a demonstration of hetero-integration of GaN-based high electron mobility transistors (HEMTs) and GaAs-based vertical cavity surface emitting lasers (VCSELs) on a single platform via a cold-welding method was performed.

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A simple and convenient method for the formation of Pt nanoparticulate films as a sensing material by controlling deposition rates is demonstrated to realize AlGaN/GaN high electron mobility transistor-based high-sensitivity hydrogen gas sensors. The Pt nanoparticulate films produced at a low deposition rate (Sample 1: 0.3 Å/s) exhibit a smooth surface and uniformly sized Pt grains, while the films produced at a high deposition rate (Sample 2: 1.

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Article Synopsis
  • A new test method was created to assess the quality of graphene flakes, like reduced graphene oxide (rGO) and graphene nanopowder (GNP), using a pelletizer for proper sampling!
  • Volume resistivity emerged as the best intrinsic measure of quality for these graphene flakes based on 4-probe measurement data, contrasting with traditional conductivity measures!
  • Analysis showed that the volume conductivity of the different graphene types was significantly influenced by oxygen content, indicating potential for better applications of powdered graphene products.
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A Schottky diode based on a heterojunction of three-dimensional (3D) nanohybrid materials, formed by hybridizing reduced graphene oxide (RGO) with epitaxial vertical zinc oxide nanorods (ZnO NRs) and AlGaN(∼25 nm)/GaN is presented as a new class of high-performance chemical sensors. The RGO nanosheet layer coated on the ZnO NRs enables the formation of a direct Schottky contact with the AlGaN layer. The sensing results of the Schottky diode with respect to NO, SO, and HCHO gases exhibit high sensitivity (0.

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This study presents a detailed fabrication method, together with validation, discussion, and analysis, for state-of-the-art silicon carbide (SiC) etching of vertical and bevelled structures by using inductively coupled plasma reactive ion etching (ICP-RIE) for microelectronic applications. Applying different gas mixtures, a maximum bevel angle of 87° (almost vertical), large-angle bevels ranging from 40° to 80°, and small-angel bevels ranging from 7° to 17° were achieved separately using distinct gas mixtures at different ratios. We found that SF with additive O was effective for vertical etching, with a best etching rate of 3050 Å/min.

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Febrile seizure (FS) is the most common seizure type in infants and young children. FS may induce functional changes in the hippocampal circuitries. Abnormality of excitatory and inhibitory neurotransmissions was previously related to wide-spread seizure attack in the hippocampus following recurrent seizure onset.

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