Publications by authors named "Hyun Chul Park"

Background/aims: The prevalence of GERD and treatment costs are continuously rising in Korea, and the importance of primary health care clinics where the most treatment of actual patients is conducted is increasing. In this study, the diagnosis of GERD, selection of therapeutic drugs, and treatment methods in primary health care clininics were investigated through a large-scale multi-dimensional surveys.

Methods: From January 2015 to December 2018, the study data of 18,010 patients with GERD were retrospectively investigated based on eletronic medical record at 542 primary health care clinics in Korea.

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Background/aims: There have been few multicenter studies on colonic polyps conducted by primary medical institutions. This study examined the detection rate of colonic polyps in primary health care institutions and the related factors while following the guidelines.

Methods: The medical records of 14,029 patients who underwent colonoscopy between January-June 2020 at 40 primary medical institutions in Korea were analyzed.

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Background: Allele frequency using short tandem repeats (STRs) is used to calculate likelihood ratio for database match, to interpret DNA mixture and to estimate ethnic groups in forensic genetics. In Korea, three population studies for 23 STR loci have been conducted with different sample size for forensic purposes.

Objective: We performed comparative analysis to determine how the difference of sample size affects the allele frequency and allele variation within same ethnic population (i.

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Recently, a method of identifying body fluids using DNA methylation has been developed (Frumkin et al., 2011). An existing multiplex assay using 9 CpG markers could differentiate 5 body fluids: semen, blood, saliva, menstrual blood, and vaginal fluid.

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Y chromosome short tandem repeats (Y-STRs) are commonly used to analyze male-specific DNA. Although biallelic patterns due to duplication events have been detected at some loci, Y-STRs generally appear as a single peak except for DYS385 because the Y chromosome is haploid. STR loci in regions of segmental duplication by homologous recombination on the Y chromosome exhibit double allelic peaks, rather than single peaks.

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This study developed a new method for forensic saliva identification using three oral bacteria, Streptococcus salivarius, Streptococcus sanguinis, and Neisseria subflava, combined with a real-time polymerase chain reaction (RT-PCR) system we called OB mRT-PCR. Analytical sensitivity results showed that the target bacteria were amplified at 10-10 copies/reaction, and analytical specificity was assessed using 24 other viruses, bacteria, and protozoa. To evaluate the OB mRT-PCR kit for forensic applications, saliva from 140 Korean individuals was tested, and at least two target bacteria were detected in all the samples.

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DNA methylation has important biological roles, such as gene expression regulation, as well as practical applications in forensics, such as in body fluid identification and age estimation. DNA methylation often occurs in the CpG site, and methylation within the CpG islands affects various cellular functions and is related to tissue-specific identification. Several programs have been developed to identify CpG islands; however, the size, location, and number of predicted CpG islands are not identical due to different search algorithms.

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Enhancing the fluorescence intensity of colloidal quantum dots (QDs) in case of color-conversion type QD light-emitting devices (LEDs) is very significant due to the large loss of QDs and their quantum yields during fabrication processes, such as patterning and spin-coating, and can therefore improve cost-effectiveness. Understanding the enhancement process is crucial for the design of metallic nanostructure substrates for enhancing the fluorescence of colloidal QDs. In this work, improved color conversion of colloidal green and red QDs coupled with aluminum (Al) and silver (Ag) nanodisk (ND) arrays designed by in-depth systematic finite-difference time domain simulations of excitation, spontaneous emission, and quantum efficiency enhancement is reported.

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Oxygen-containing functional groups such as epoxy, hydroxyl, carboxylic, and carboxyl groups have a great influence on the luminescence properties of graphene oxide quantum dots (GOQDs). Understanding their roles is essential for the design and optimization of GOQD performance. Herein, we investigate the effect of epoxide functional groups in GOQDs on the luminescence mechanism through passivation of the epoxide functional groups using the alkyl ligand oleylamine.

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We genotyped and calculated the forensic parameters of 10 non-CODIS loci and 2 CODIS loci of 990 Korean individuals using the Investigator HDplex kit. No significant deviations from Hardy-Weinberg equilibrium (after Bonferroni correction for multiple testing) or genetic linkage disequilibrium were observed. The calculated matching probability and power of discrimination ranged from 0.

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In this study, we compared two recently released commercial Y-chromosomal short tandem repeat (Y-STR) kits: the PowerPlex Y23 System (PPY23) and Yfiler® Plus PCR amplification kit (YPlus). We performed validation studies, including sensitivity, tolerance to PCR inhibitors, and mixture analysis, and a population genetics study using 306 unrelated South Korean males. PPY23 and YPlus showed similar sensitivity, but PPY23 showed higher tolerance to humic acid than YPlus.

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The thumb is the most important part of the hand. If thumb is amputated, all efforts should be made to replant it to preserve hand functions. Good functional outcome can be obtained with successful thumb replantation than with other reconstructive surgery.

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Ethnopharmacological Relevance: Cornus walteri Wangerin has been used in oriental traditional medicine for the treatment of antidiarrheal and inflammation.

Aim Of The Study: The efficacy of Cornus walteri Wangerin on skin anti-photoaging was investigated.

Materials And Methods: Hydrolyzed Cornus walteri Wangerin leaf was tested for the anti-photoaging effects against ultraviolet B (UVB)-induced matrix metalloproteinase (MMP)-1, pro-inflammatory cytokines using human reconstituted skin (KeraSkin™-FT) and also tested for elastase activity in vitro.

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Allele frequencies for 23 autosomal short tandem repeat loci (D3S1358, vWA, D16S539, CSF1PO, TPOX, D8S1179, D21S11, D18S51, TH01, FGA, D5S818, D13S317, D7S820, D2S441, D19S433, D22S1045, D10S1248, D1S1656, D12S391, D2S1338, SE33, Penta D, Penta E), 1 Y-chromosome short tandem repeat locus (DYS391) and Y indel were obtained from 1000 unrelated individuals of the Korean population.

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Although squamous cell carcinoma (SCC) is the second most common nonmelanoma skin cancer, clinicians have difficulty diagnosing SCC of the toe because its clinical features can mimic other less serious diseases. Clinicians are especially prone to misdiagnose SCC of the toe as diabetic foot ulcer in patients with diabetes mellitus because of the clinical similarity of the 2 ailments. SCC of the toe is generally considered to have a low risk of metastasis.

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Estrogens and estrogen receptors (ESRs) have been implicated in the stimulation of aberrant prostate growth and the development of prostate diseases. The aim of the present study was to investigate four single nucleotide polymorphisms (SNPs) of the ESR2 gene in order to examine whether is a susceptibility gene for benign prostatic hyperplasia (BPH). In order to evaluate whether an association exists between and BPH risk, four polymorphisms [rs4986938 (intron), rs17766755 (intron), rs12435857 (intron) and rs1256049 (Val328Val)] of the ESR2 gene were genotyped by direct sequencing.

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We experimentally demonstrate a novel cosine apodization technique for dual-resonance all-fiber acoustic-optic tunable filter. The technique is based on a hybrid control of input acoustic polarization state and circumferential fiber twist. We will show that intrinsic sidelobe spectra occurring between dual filtering bands are successfully suppressed through our approach, which will be also theoretically confirmed via our analytical and numerical studies.

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ABO genotyping has been routinely used to identify suspects or unknown remains in crime investigations. Probe-based fluorescence melting curve analysis (FMCA) is a powerful tool for mutation detection and is based on melting temperature shifts due to thermal denaturation. In the present study, we developed a new method for ABO genotyping using peptide nucleic acid (PNA) probe-based FMCA.

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Vascular clamps are often used during microvascular repair and anastomosis. However, pressure exerted by the clamps may damage the vessels, which compromises patency of vessels. This article reports on a microsurgical suture technique performed without any clamp to avoid clamp-related problems.

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We propose a super-channel flexible wavelength division multiplexing (WDM) receiver architecture. The receiver, which requires no optical filtering, only a pair (I and Q phases) of coherent optical detectors, and an electrical receiver system, can simultaneously recover multiple wavelength-multiplexed channels using cascaded optical and electrical down-conversion. The receiver data capacity increases in proportion to the number of electrical sub-carrier channels.

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During replantation of distal fingertip amputation, identification of the artery is the most important but time consuming procedure. Depending on the damaged arterial structure, we classified distal fingertip amputations into 4 zones, on the basis of three dimensional concept. Zone 1 injury was defined as damage to the proximal central pulp artery; zone 2 injury, damage to the branch of the central pulp artery; zone 3 injury, damage to the distal central pulp artery; and zone 4 injury, no injury to the central pulp artery, injury only to the lateral pulp artery.

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Compared to traditional optics, photonic integrated circuits have advantages in size, weight, performance, reliability, power consumption, and cost. The size and stability also enable them to realize unique functions in coherent optics. Optical phase-locked loop (OPLL) based transmitters and receivers are examples.

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A highly integrated 40 Gbit/s coherent optical receiver is reported using a Costas loop as a homodyne optical phase locked loop (OPLL). A photonic IC, an electrical IC, and a hybrid loop filter are characterized, and the feedback loop system is fully analyzed to build a stable homodyne OPLL. All components are integrated on a single substrate within the compact size of 10 × 10mm(2), and a 1.

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DNA barcoding has been widely used in species identification and biodiversity research. A short fragment of the mitochondrial cytochrome c oxidase subunit I (COI) sequence serves as a DNA bio-barcode. We collected DNA barcodes, based on COI sequences from 156 species (529 sequences) of fish, insects, and shellfish.

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