Laryngeal ultrasound for vocal cord evaluation

Jung-Woo Woo,Hyunsuk Suh,Ra-Yeong Song,Joon-Hyop Lee,Hyeong Won Yu,Yong Joon Suh,Jun Woo Jung,Hyungju Kwon,Su-jin Kim,Young Jun Chai,Kyu Hyung Kim,June Young Choi,Kyu Eun Lee,Yeo-Kyu Youn 대한외과학회 2014 대한외과학회 학술대회 초록집 Vol.2014 No.11

Resistive switching characteristics of a modified active electrode and Ti buffer layer in CuSe-based atomic switch

Woo, Hyunsuk,Vishwanath, Sujaya Kumar,Jeon, Sanghun Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.753 No.-

<P><B>Abstract</B></P> <P>Atomic switches are well-known promising candidates for future application in non-volatile logic memory devices. The resistive switching characteristics of these devices depend on the formation of a conductive filament (CF) by active metal electrodes. However, the formation of a stable CF is still a challenge owing to filament overgrowth in the solid electrolyte. To achieve controlled CF growth, we have used a modified active electrode with different Cu<SUB>x</SUB>Se<SUB>1−x</SUB> composition ratios (0.01 < x < 0.45) and a titanium (Ti) buffer layer. The optimum composition was determined to be Cu<SUB>0.11</SUB>Se<SUB>0.89</SUB>/Ti (2.5 nm) for which excellent resistive switching properties were observed, such as a high on/off ratio of 10<SUP>4</SUP>, low operating voltage, uniform resistance distribution, ten-year data retention at 85 °C, and <B>uniform endurance</B> (2000 cycles). The improvement is can be described from the high controllability of the oxidation-reduction reaction rate of the optimized CuSe modified active electrode by the means of Ti buffer layer and the TiO bond formation at the Ti/Al<SUB>2</SUB>O<SUB>3</SUB> interface. In addition, depth profiles of the conductive filament based on Cu<SUB>0.11</SUB>Se<SUB>0.89</SUB> with a Ti buffer layer were studied by performing current atomic force microscopy (I-AFM) to evaluate the enhancements in electrical performance and reliability resulting from the insertion of the Ti buffer layer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First report on CuSe based atomic switch. </LI> <LI> Improved reliability depends on interface reaction at Ti/Al<SUB>2</SUB>O<SUB>3</SUB>. </LI> <LI> CuSe/Ti/Al<SUB>2</SUB>O<SUB>3</SUB>/Pt device showed highly stable retention at 102 °C for ten years. </LI> <LI> 860 nm<SUP>2</SUP> area of cross section of conductive filament is observed from I-AFM. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Resistive switching characteristics of CuSe/Ti-based atomic switch with controlled filament.</P> <P>[DISPLAY OMISSION]</P>

Determination of intrinsic mobility of a bilayer oxide thin-film transistor by pulsed <i>I</i>–<i>V</i> method

Woo, Hyunsuk,Kim, Taeho,Hur, Jihyun,Jeon, Sanghun IOP 2017 Nanotechnology Vol.28 No.17

<P>Amorphous oxide semiconductor thin-film transistors (TFT) have been considered as outstanding switch devices owing to their high mobility. However, because of their amorphous channel material with a certain level of density of states, a fast transient charging effect in an oxide TFT occurs, leading to an underestimation of the mobility value. In this paper, the effects of the fast charging of high-performance bilayer oxide semiconductor TFTs on mobility are examined in order to determine an accurate mobility extraction method. In addition, an approach based on a pulse <I>I</I> <SUB>D</SUB> <I>–V</I> <SUB>G</SUB> measurement method is proposed to determine the intrinsic mobility value. Even with the short pulse <I>I</I> <SUB>D</SUB> <I>–V</I> <SUB>G</SUB> measurement, a certain level of fast transient charge trapping cannot be avoided as long as the charge-trap start time is shorter than the pulse rising time. Using a pulse-amplitude-dependent threshold voltage characterization method, we estimated a correction factor for the apparent mobility, thus allowing us to determine the intrinsic mobility.</P>

Excellent Resistive Switching Performance of Cu-Se-Based Atomic Switch Using Lanthanide Metal Nanolayer at the Cu-Se/Al₂O₃ Interface

Woo, Hyunsuk,Vishwanath, Sujaya Kumar,Jeon, Sanghun American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.9

<P>The next-generation electronic society is dependent on the performance of nonvolatile memory devices, which has been continuously improving. In the last few years, many memory devices have been introduced. However, atomic switches are considered to be a simple and reliable basis for next-generation nonvolatile devices. In general, atomic switch-based resistive switching is controlled by electrochemical metallization. However, excess ion injection from the entire area of the active electrode into the switching layer causes device nonuniformity and degradation of reliability. Here, we propose the fabrication of a high-performance atomic switch based on Cu<SUB><I>x</I></SUB>-Se<SUB>1-<I>x</I></SUB> by inserting lanthanide (Ln) metal buffer layers such as neodymium (Nd), samarium (Sm), dysprosium (Dy), or lutetium (Lu) between the active metal layer and the electrolyte. Current-atomic force microscopy results confirm that Cu ions penetrate through the Ln-buffer layer and form thin conductive filaments inside the switching layer. Compared with the Pt/Cu<SUB><I>x</I></SUB>-Se<SUB>1-<I>x</I></SUB>/Al<SUB>2</SUB>O<SUB>3</SUB>/Pt device, the optimized Pt/Cu<SUB><I>x</I></SUB>-Se<SUB>1-<I>x</I></SUB>/Ln/Al<SUB>2</SUB>O<SUB>3</SUB>/Pt devices show improvement in the on/off resistance ratio (10<SUP>2</SUP>-10<SUP>7</SUP>), retention (10 years/85 °C), endurance (∼10 000 cycles), and uniform resistance state distribution.</P> [FIG OMISSION]</BR>

Age Stratified Numbers Needed to Treat of Latent Tuberculosis Infection among the Population Without Recent Tuberculosis Exposure or Medical Risk Factors: 2-year Follow-up Results of TBfreeCorea

( Hyung Woo Kim ),( Ju Sang Kim ),( Jinsoo Min ),( Joon Young Choi ),( Ah Young Shin ),( Deokjae Han ),( Jun-pyo Myong ),( Yunhee Lee ),( Hyeon Woo Yim ),( Hyunsuk Jeong ),( Sanghyuk Bae ),( Eunhye Sh 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.0

Background This study was designed to estimate the treatment effect of latent tuberculosis infection (LTBI) among the participants of TBfreeCorea, who mostly did not have known tuberculosis (TB) exposure history and medical risk factors for TB. Methods Among the cohort of TBfreeCorea, participants who underwent Interferon gamma release assay (IGRA) in 2017 were followed up until January 2nd, 2020. Those with positive IGRA Results but did not initiate LTBI treatment and those who completed treatment were included. Two-year cumulative TB incidence and numbers needed to treat (NNT) were calculated by each congregated setting with age stratification. Participants were classified into 5 groups with interferon (IFN) level of IGRA - those with IFN >10 IU/ml, then the others into quartiles (Q1(0.35-0.67), Q2(0.67-1.41), Q3(1.41-3.33), Q4(3.33-10.0)). NNT by IFN level was analyzed with age stratification. Results Among the 90,048 participants who were IGRA (+) but did not initiated LTBI treatment, 318 cases of active TB were identified whereas 25 cases out of 39,050 participants who completed LTBI treatment (2-year cumulative incidence: 353.1 vs 64.0 per 100,000 population). In various congregate settings, candidates for military conscription and high school 1st grade students, who were in their 10s or 20s, showed relatively low NNTs (131 (96.6-199.8), 131 (91.2-229.5), respectively). NNTs of staffs in social welfare facilities, educational institutions and medical institutions were 423 (307.2-673.9), 599 (443.3-919.0), 283 (217.3-401.8), respectively. However, younger adults (aged 20-34) in each congregate setting showed relatively low NNTs - 120 (70.7-385.5), 194 (121.8-473.5), 83 (60.8-128.7), respectively. NNTs decreased with higher IFN levels, 1114 (625.1-5074.5) for Q1 group, 568 (378.3-1138.9) for Q2 group, 442 (306.8-788.1) for Q3 group, 220 (173.8-298.9) for Q4 group and 165 (133.4-215.6) for those with IFN level >10 IU/ml. Conclusions Treatment effect of LTBI was prominent among the participants who were young and those with higher IFN level. Conclusions The location and extent of involvement in the medulla were the most important factors associated with the severity of dysphagia after LMI.

Predictive Value of Interferon Gamma Release Assay for Incident Active Tuberculosis: 2-year Follow-up Results of TBfreeCorea

( Hyung Woo Kim ),( Ju Sang Kim ),( Jinsoo Min ),( Joon Young Choi ),( Ah Young Shin ),( Deokjae Han ),( Jun-pyo Myong ),( Yunhee Lee ),( Hyeon Woo Yim ),( Hyunsuk Jeong ),( Sanghyuk Bae ),( Eunhye Sh 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.-

Background The aim of this study was to investigate the predictive value of interferon gamma release assay (IGRA) for incident active tuberculosis (TB). Methods Among the cohort of TBfreeCorea, participants who underwent IGRA in 2017 were followed up until January 2nd, 2020. To investigate the natural history of LTBI, those with negative IGRA Results and those with positive Results but who did not initiate LTBI treatment were included in this study. Sensitivity, specificity and predictive values were investigated with 2-year cumulative TB incidence. Effects of interferon (IFN) level and other risk factors on incident TB cases was analyzed in a Cox proportional hazard model with time varying covariates. Results Among the enrolled 810,294 participants, a total of 570 cases of active TB were identified. Two-year cumulative TB incidence was 62.7 cases per 100,000 population. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 63.39%, 89.44%, 0.38% and 99.97% respectively, with current cutoff value of 0.35 IU/mL. PPV was higher among the young aged group - 0.90% in age group < 20 and 0.96% in age group 20-35. When cutoff value was raised to 0.67, 1.41 and 3.33 IU/ml, PPV were improved to 0.44%, 0.51% and 0.62%, respectively, but sensitivity decreased to 58.46%, 48.62% and 36.81%. In a Cox proportional hazard model, risk of active TB increased with higher IFN level - when compared with IGRA negative group, hazard ratio among the group with IFN level of 0.35-0.67, 0.67-1.41, 1.41-3.33, 3.33-10.0 and > 10 IU/ml was 6.56 (4.29-10.03), 13.38 (9.56-18.73), 18.15 (13.19-24.99), 31.81 (24.01-42.16), 43.51 (32.21-58.79), respectively. In a subgroup analysis stratified by age, such tendency was more prominent in younger age group, whereas obscured in elderly group. Conclusions IGRA showed quantitative predictive value for TB incidence, especially among young age group. However, low PPV remains a limitation.

Impact of Current Latent Tuberculosis Infection Strategy - Screening Individuals with Medical Risk Factors for Tuberculosis

( Hyung Woo Kim ),( Ju Sang Kim ),( Jinsoo Min ),( Ah Young Shin ),( Joon Young Choi ),( Jun-pyo Myong ),( Yunhee Lee ),( Hyeon Woo Yim ),( Hyunsuk Jeong ),( Sanghyuk Bae ),( Ji Young Kang ),( Hyeon-k 대한결핵 및 호흡기학회 2021 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.129 No.-

Background This study aims to estimate the impact of current latent tuberculosis infection screening (LTBI) strategy - screening individuals with medical risk factors for tuberculosis (TB). Methods 8 prevalent cohorts extracted from National Health Information Database including individuals who had disease with high or moderate TB risk specified in Korean guidelines for TB at the timepoint of January 1st, 2018 were followed up for a year by matching with nationwide notified TB cases in 2018. Standardized incidence ratio (SIR) of TB was calculated in each cohort by comparing with nationwide TB incidence after stratification by age and sex. The proportion of TB cases from each cohort among nationwide TB cases notified in 2018 was also investigated. Results A total of 19,856 patients with human immunodeficiency virus, 63,003 patients in post-organ transplantation status, 36,946 patients who underwent tumor necrosis factor antagonist treatment, 130,885 patients with end-stage renal disease, 253,585 patients in post-gastrectomy status, 65,647 patients with head or neck malignancy, 127,850 patients with hematologic malignancy and 3,721,100 patients with diabetes mellitus (DM) were identified. SIR of TB in each cohort was 6.63 (95% confidence interval, 5.47-8.04), 3.26 (2.76-3.86), 4.97 (4.13-5.99), 2.73 (2.52-2.96), 1.60 (1.48-1.73), 1.68 (1.46-1.93), 2.05 (1.85- 2.28) and 1.30 (1.27-1.33), respectively. Among 33,795 nationwide TB cases notified in 2018, the number of patients from each cohort was 103 (0.3%), 134 (0.4%), 111 (0.3%), 601 (1.8%), 594 (1.8%), 190 (0.6%), 348 (1.0%) and 6,835 (20.2%), respectively. Patients who had disease with high or moderate TB risk accounted for 30.6% (4,677 / 15,281) of TB cases in elderly population aged 65 or over. Without patients from the DM cohort, the proportion had decreased into 7.0% (1,063 / 15,281). Conclusions Impact of current LTBI strategy focusing on medical high-risk group is limited. Further high-risk groups should be identified.

Latent Tuberculosis Infection Screening and Treatment in Congregate Settings (TB FREE COREA): Demographic Profiles of Interferon-Gamma Release Assay Cohort

Kim Hyung Woo,Min Jinsoo,Choi Joon Young,Shin Ah Young,Myong Jun-Pyo,Lee Yunhee,Yim Hyeon Woo,Jeong Hyunsuk,Bae Sanghyuk,Shim Eunhye,In Hyekyung,Chun Chaemin,Kim Gahee,Kang Ji Young,Lee Sung-Soon,Park 대한의학회 2021 Journal of Korean medical science Vol.36 No.36

In 2017, the Korean government launched an unprecedentedly large-scaled latent tuberculosis infection (LTBI) screening project which covered more than a million individuals in congregate settings. A total of 1,047,689 participants of source population (n = 2,336,157) underwent LTBI testing from 2017 to 2018. The overall LTBI test uptake rate during this project was 44.8%. Workers in daycare centers (83.5%) and kindergartens (78.9%) showed high participation rate. A total of 1,012,206 individuals with valid results of interferongamma release assay (IGRA) were selected to constitute the IGRA cohort. Most of the enrolled participants in the IGRA cohort were in their working age. Approximately, threequarters of total enrolled population were female. Investigating the LTBI prevalence, stages of LTBI care cascade, natural history of LTBI, efficacy of LTBI treatment and cost-effectiveness of LTBI screening are feasible within this IGRA cohort.

Associations of active and passive tobacco exposure with elevated blood pressure in Korean adolescents

Hyerin Park(Hyerin Park),Hyunsuk Jeong(Hyunsuk Jeong),Hyeon Woo Yim(Hyeon Woo Yim),Sanghyuk Bae(Sanghyuk Bae) 한국역학회 2024 Epidemiology and Health Vol.46 No.-

Changes in bioimpedance analysis components before and after hemodialysis

( Hyunsuk Kim ),( Gwang Ho Choi ),( Kwang Eon Shim ),( Jung Hoon Lee ),( Nam Ju Heo ),( Kwon-wook Joo ),( Jong-woo Yoon ),( Yun Kyu Oh ) 대한신장학회 2018 Kidney Research and Clinical Practice Vol.37 No.4

Background: This study compared nutritional parameters in hemodialysis (HD) subjects and controls using bioimpedance analysis (BIA) and investigated how BIA components changed before and after HD. Methods: This cross-sectional study included 147 subjects on maintenance HD from two hospitals and 298 propensity score-matched controls from one healthcare center. BIA was performed pre- and post-HD at mid-week dialysis sessions. Results: Extracellular water/total body water (ECW/TBW) and waist-hip ratio were higher in the HD patients; the other variables were higher in the control group. The cardiothoracic ratio correlated best with overhydration (r = 0.425, P < 0.01) in HD subjects. Blood pressure, hemoglobin, creatinine, and uric acid positively correlated with the lean tissue index in controls; however, most of these nutritional markers did not show significant correlations in HD subjects. Normal hydrated weight was predicted to be higher in the pre-HD than post-HD measurements. Predicted ultrafiltration (UF) volume difference based on pre- and post-HD ECW/TBW and measured UF volume difference showed a close correlation (r² = 0.924, P < 0.01). Remarkably, the leg phase angle increased in the post-HD period. Conclusion: The estimated normal hydrated weight using ECW/TBW can be a good marker for determining dry weight. HD subjects had higher ECW/TBW but most nutritional indices were inferior to those of controls. It was possible to predict UF volume differences using BIA, but the post-HD increase in leg phase angle, a nutritional marker, must be interpreted with caution.