A Multicenter Study of Pertussis Infection in Adults with Coughing in Korea: PCR-Based Study

Park, Sunghoon,Lee, Myung-Gu,Lee, Kwan Ho,Park, Yong Bum,Yoo, Kwang Ha,Park, Jeong-Woong,Kim, Changhwan,Lee, Yong Chul,Park, Jae Seuk,Kwon, Yong Soo,Seo, Ki-Hyun,Kim, Hui Jung,Kwak, Seung Min,Kim, Ju- The Korean Academy of Tuberculosis and Respiratory 2012 Tuberculosis and Respiratory Diseases Vol.73 No.5

Background: Limited data on the incidence and clinical characteristics of adult pertussis infections are available in Korea. Methods: Thirty-one hospitals and the Korean Centers for Disease Control and Prevention collaborated to investigate the incidence and clinical characteristics of pertussis infections among adults with a bothersome cough in non-outbreak, ordinary outpatient settings. Nasopharyngeal aspirates or nasopharyngeal swabs were collected for polymerase chain reaction (PCR) and culture tests. Results: The study enrolled 934 patients between September 2009 and April 2011. Five patients were diagnosed as confirmed cases, satisfying both clinical and laboratory criteria (five positive PCR and one concurrent positive culture). Among 607 patients with cough duration of at least 2 weeks, 504 satisfied the clinical criteria of the US Centers for Disease Control and Prevention (i.e., probable case). The clinical pertussis cases (i.e., both probable and confirmed cases) had a wide age distribution ($45.7{\pm}15.5$ years) and cough duration (median, 30 days; interquartile range, 18.0~50.0 days). In addition, sputum, rhinorrhea, and myalgia were less common and dyspnea was more common in the clinical cases, compared to the others (p=0.037, p=0.006, p=0.005, and p=0.030, respectively). Conclusion: The positive rate of pertussis infection may be low in non-outbreak, ordinary clinical settings if a PCR-based method is used. However, further prospective, well-designed, multicenter studies are needed.

Direct and Indirect Costs of Chronic Obstructive Pulmonary Disease in Korea

Kim, Changhwan,Kim, Younhee,Yang, Dong-Wook,Rhee, Chin Kook,Kim, Sung Kyoung,Hwang, Yong-Il,Park, Yong Bum,Lee, Young Mok,Jin, Seonglim,Park, Jinkyeong,Hahm, Cho-Rom,Park, Chang-Han,Park, So Yeon,Jung The Korean Academy of Tuberculosis and Respiratory 2019 Tuberculosis and Respiratory Diseases Vol.82 No.1

Background: Understanding the burden of disease is important to establish cost-effective treatment strategies and to allocate healthcare resources appropriately. However, little reliable information is available regarding the overall economic burden imposed by chronic obstructive pulmonary disease (COPD) in Korea. Methods: This study is a multicenter observational research on the COPD burden in Korea. Total COPD costs were comprised of three categories: direct medical, direct non-medical, and indirect costs. For direct medical costs, institutional investigation was performed at 13 medical facilities mainly based on the claims data. For direct non-medical and indirect costs, site-based surveys were administered to the COPD patients during routine visits. Total costs were estimated using the COPD population defined in the recent report. Results: The estimated total costs were approximately 1,245 million US dollar (1,408 billion Korean won). Direct medical costs comprised approximately 20% of the total estimated costs. Of these, formal medical costs held more than 80%. As direct non-medical costs, nursing costs made up the largest percentage (39%) of the total estimated costs. Costs for COPD-related loss of productivity formed four fifths of indirect costs, and accounted for up to 33% of the total costs. Conclusion: This study shows for the first time the direct and indirect costs of COPD in Korea. The total costs were enormous, and the costs of nursing and lost productivity comprised approximately 70% of total costs. The results provide insight for an effective allocation of healthcare resources and to inform establishment of strategies to reduce national burden of COPD.

Direct and Indirect Costs of Chronic Obstructive Pulmonary Disease in Korea

( Changhwan Kim ),( Younhee Kim ),( Dong-Wook Yang ),( Chin Kook Rhee ),( Sung Kyoung Kim ),( Yong-Il Hwang ),( Yong Bum Park ),( Young Mok Lee ),( Seonglim Jin ),( Jinkyeong Park ),( Cho-Rom Hahm ),( 대한결핵 및 호흡기학회 2019 Tuberculosis and Respiratory Diseases Vol.82 No.1

Background: Understanding the burden of disease is important to establish cost-effective treatment strategies and to allocate healthcare resources appropriately. However, little reliable information is available regarding the overall economic burden imposed by chronic obstructive pulmonary disease (COPD) in Korea. Methods: This study is a multicenter observational research on the COPD burden in Korea. Total COPD costs were comprised of three categories: direct medical, direct non-medical, and indirect costs. For direct medical costs, institutional investigation was performed at 13 medical facilities mainly based on the claims data. For direct non-medical and indirect costs, site-based surveys were administered to the COPD patients during routine visits. Total costs were estimated using the COPD population defined in the recent report. Results: The estimated total costs were approximately 1,245 million US dollar (1,408 billion Korean won). Direct medical costs comprised approximately 20% of the total estimated costs. Of these, formal medical costs held more than 80%. As direct non-medical costs, nursing costs made up the largest percentage (39%) of the total estimated costs. Costs for COPD-related loss of productivity formed four fifths of indirect costs, and accounted for up to 33% of the total costs. Conclusion: This study shows for the first time the direct and indirect costs of COPD in Korea. The total costs were enormous, and the costs of nursing and lost productivity comprised approximately 70% of total costs. The results provide insight for an effective allocation of healthcare resources and to inform establishment of strategies to reduce national burden of COPD.

A Signal Detection Technique for OFDMA-based Wireless Mesh Networks with TDoAs

Park, Changhwan,Choi, Joohyung,Cho, Yong Soo The Korean Institute of Communications and Informa 2015 ICT Express Vol.1 No.1

In this paper, the effect of time difference of arrival (TDoA) is investigated for distributed nodes in OFDMA-based wireless mesh networks (WMNs). In order to minimize the interferences caused by TDoA in WMNs, the optimal starting point of FFT window at the receiver side of a node is derived by maximizing the effective SINR for each subcarrier. Also, a signal detection technique, called two dimensional ordered successive interference cancellation (TD-OSIC), is proposed for WMNs with TDoAs. It was shown via simulation that the proposed technique can achieve effective SINR and BER performances similar to the ideal case (no TDoA), even in WMNs with large TDoAs.

S-455 Periostin-binding DNA aptamer ameliorates peritoneal dialysis-induced peritoneal fibrosis

( Changhwan Seo ),( Bo Young Nam ),( Meiyan Wu ),( Ji Min Park ),( Jae Eun Um ),( Seonghun Kim ),( Hye-young Kang ),( Seohyun Park ),( Su-young Jung ),( Jong Hyun Jhee ),( Hae-ryong Yun ),( Hyoungnae 대한내과학회 2016 대한내과학회 추계학술발표논문집 Vol.2016 No.1

Background: Peritoneal fibrosis (PF) is a major complication in patients on peritoneal dialysis (PD). In PD-related PF, the protein expressions of various extracellular matrix including periostin are known to be increased via the transforming growth factor-β1 (TGF-β1) pathway. This study was undertaken to evaluate the impact of periostin inhibition by novel aptamer-based inhibitor on TGF-β1-induced epithelial-mesenchymal transition (EMT). Methods: In vitro, primary HPMCs were exposed to TGF-β1 (2 ng/ml) to induce EMT and fibrosis with or without periostin siRNA (100 nM) or periostin-binding DNA aptamer (200 nM). In vivo, PD catheters were inserted into 48 C57BL/6 mice, and saline (C group, N=24) or 4.25% PD solution (PD group, N=24) was infused for 4 weeks. Twelve mice from each group were treated with periostin-binding DNA aptamer (500 μg/kg/d) (PA). mRNA and protein expressions of periostin, fibronectin, α-smooth muscle actin (α-SMA), snail, and E-cadherin in HPMCs and mouse peritoneum were evaluated by quantitative real-time polymerase chain reaction and western blot analysis, respectively. PF was also assessed by Masson’s trichrome (MT) staining. Results: In vitro, TGF-β1 treatment significantly up-regulated periostin, fibronectin, α-SMA, and snail expressions, while E-cadherin expression was significantly decreased by TGF-β1 in cultured HPMCs (p<0.01). Not only periostin siRNA but also periostin-binding DNA aptamer significantly attenuated TGF-β1-induced periostin, fibronectin, α-SMA, and snail expressions and significantly restored E-cadherin expression in HPMCs (p<0.05). In vivo, the expressions of periostin, fibronectin, α-SMA, and snail were significantly increased, whereas E-cadherin expression was significantly decreased in the peritoneum of PD mice (p<0.05). The thickness of the submesothelial layer and the intensity of MT staining in the peritoneum were significantly higher in PD mice compared to C mice (p<0.05). These changes in the PD group were significantly abrogated by PA treatment (p<0.05). Conclusions: These findings suggest that PA can be a potential therapeutic strategy for PF in PD patients.

The Effects of a Thermal Recovery Process in In-Ga-Zn-O (IGZO) Thin Films Transistor

Park, Hyung-Youl,Yoo, Gwangwe,Lee, Hanjae,Lim, Myung-Hoon,Baek, Jung Woo,Choi, Changhwan,Park, Jin-Hong American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11

<P>In this paper, we demonstrated the effect of titanium (Ti) diffusion and modulation of interface traps by carrying out an annealing process on In-Ga-Zn-O (IGZO). The effect of diffused Ti atoms from the source/drain (S/D) electrodes was systematically investigated through secondary ion mass spectroscopy, X-ray photoelectron spectroscopy, HSC chemistry simulation, and electrical measurements. Higher concentrations of Ti and oxygen vacancies were observed with increasing annealing temperature. In addition, we demonstrated that the electrical stability of the IGZO thin films transistors (TFTs) was enhanced by a second thermal annealing process performed at temperature 50 degrees C lower than the first annealing step to diffuse Ti atoms in the lateral direction with minimal effects on the channel conductivity. As a result, we obtained a threshold voltage shift (Delta V-TH) of only 2.9 V after the first annealing step at 300 degrees C for 1 hour and a second annealing step at 250 degrees C for 3 hours with a channel length of 4 mu m.</P>

Elongated Lifetime and Enhanced Flux of Hot Electrons on a Perovskite Plasmonic Nanodiode

Park, Yujin,Choi, Jungkweon,Lee, Changhwan,Cho, An-Na,Cho, Dae Won,Park, Nam-Gyu,Ihee, Hyotcherl,Park, Jeong Young American Chemical Society 2019 NANO LETTERS Vol.19 No.8

<P>A fundamental understanding of hot electron transport is critical for developing efficient hot-carrier-based solar cells. There have been significant efforts to enhance hot electron flux, and it has been found that a key factor affecting the hot electron flux is the lifetime of the hot electrons. Here, we report a combined study of hot electron flux and the lifetime of hot carriers using a perovskite-modified plasmonic nanodiode. We found that perovskite deposition on a plasmonic nanodiode can considerably improve hot electron generation induced by photon absorption. The perovskite plasmonic nanodiode consists of MAPbI<SUB>3</SUB> layers covering a plasmonic-Au/TiO<SUB>2</SUB> Schottky junction that is composed of randomly connected Au nanoislands deposited on a TiO<SUB>2</SUB> layer. The measured incident photon-to-electron conversion efficiency and the short-circuit photocurrent show a significantly improved solar-to-electrical conversion performance of this nanodiode. Such an improvement is ascribed to the improved hot electron flux in MAPbI<SUB>3</SUB> caused by effective light absorption from near-field enhancement of plasmonic Au and the efficient capture of hot electrons from Au nanoislands via the formation of a three-dimensional Schottky interface. The relation between the lifetime and flux of hot electrons was confirmed by femtosecond transient absorption spectroscopy that showed considerably longer hot electron lifetimes in MAPbI<SUB>3</SUB> combined with the plasmonic Au structure. These findings can provide a fundamental understanding of hot electron generation and transport in perovskite, which can provide helpful guidance to designing efficient hot carrier photovoltaics.</P> [FIG OMISSION]</BR>

S-500 The Risk of Warfarin Use in Patients with Atrial Fibrillation Undergoing Hemodialysis

( Changhwan Seo ),( Chang-yun Yoon ),( Youn Kyung Kee ),( Hyoungnae Kim ),( Seohyun Park ),( Hae Ryong Yun ),( Su-young Jung ),( Jong Hyun Jhee ),( Jung Tak Park ),( Seung Hyeok Han ),( Shin-wook Kang 대한내과학회 2016 대한내과학회 추계학술발표논문집 Vol.2016 No.1

Background: The aim of this study is to elucidate the benefits and risks of the use of warfarin in patients with AF undergoing dialysis using a population-based, large-scale Korean registry data to compare clinical outcomes between warfarin users and non-users. Methods: Data were extracted from the Health Insurance Review and Assessment Service (HIRA), which is a nationwide mandatory social insurance database of the total Korean citizens who has enrolled in National Health Information Service between 2009 and 2013. The end-stage renal disease-atrial fibrillation (ESRD-AF) cohort was extracted from the entire Korean population identified ESRD patients and AF patients. Major adverse cardiac and cerebrovascular events (MACCEs) were defined as the composites of acute myocardial infarction, ischemic stroke, or peripheral arterial disease, while all bleeding events were defined as the composites of hemorrhagic stroke and gastrointestinal bleeding. Results: The mean age was 66.6±12.2 years, and 5806 (58.2%) were men. Among 9974 dialysis patients with AF, 2921 (29.3%) were warfarin users. After propensity score matching to adjust for all described baseline differences, total 5548 subjects were remained after matching, and the differences of baseline variables were distributed equally in both warfarin user and non-user groups. During a mean follow-up duration of 15.9±11.1 months, MACCEs and all bleeding events were occurred in 1756 (17.6%) and 883 (8.9%) patients, respectively. In a multiple Cox model with age, sex, history of diabetes, hypertension, malignancy and liver cirrhosis, the use of medications, CHA2DS2-VASc and HAS-BLED scores being used as covariates, warfarin use was significantly associated with an increased risk of hemorrhagic stroke [hazard (HR), 1.441; 95% confidence interval (CI), 1.09-1.91; p=0.010]. Furthermore, the significant relationship between warfarin use and hemorrhagic stroke was still remained in matched subjects (HR, 1.563; 95% CI, 1.10-2.22; p=0.013). Conclusions: This finding suggests that the use of warfarin in dialysis patients would be more cautious even clearly indicated in general population.

S-498 Low Dentin Matrix Protein 1 is Associated with Cardiovascular Events in Peritoneal Dialysis

( Changhwan Seo ),( Chang-yun Yoon ),( Bo Young Nam ),( Youn Kyung Kee ),( Hyoungnae Kim ),( Seohyun Park ),( Hae Ryong Yun ),( Su-young Jung ),( Jong Hyun Jhee ),( Jung Tak Park ),( Seung Hyeok Han ) 대한내과학회 2016 대한내과학회 추계학술발표논문집 Vol.2016 No.1

Objective: Recent reports demonstrated that dentin matrix protein 1 (DMP1) acts as an inhibitor of vascular calcification and might be a potential biomarker for chronic kidney disease-mineral and bone disorder, however, the role of DMP1 has never been explored in dialysis patients. We investigated the prognostic value of DMP1 on cardiovascular outcomes in prevalent peritoneal dialysis patients. Design and Method: We recruited 223 prevalent peritoneal dialysis and divided them into high and low DMP1 groups according to log transformed plasma DMP1 levels. Lateral lumbar spine radiographs were used for measurement of vascular calcification. Major cardiovascular events were compared between the two groups. A Cox proportional hazards analysis determined whether DMP1 is independently associated with cardiovascular outcomes. Results: The mean age was 52.1±11.8 years, and 116 [52.0%] patients were male. The median value of log DMP1 was 0.91 (0.32-2.81 ng/mL). The multiple logistic regression analysis indicated that DMP1 levels were independently associated with the presence of vascular calcification after adjustment for multiple confounding factors (odds ratio, 0.766; 95% confidence interval [CI], 0.634-0.924; p=0.005). During a mean follow-up duration of 34.6 months, incident cardiovascular events were observed in 41 (18.4%) patients. A Kaplan-Meier plot showed that the low DMP1 group had a significantly higher rate of incident cardiovascular events compared with the high DMP1 group (log-rank test, p=0.026). In addition, multiple Cox proportional hazard analysis showed that low DMP1 was significantly associated with incident cardiovascular events (log 1 increase: hazard ratio=0.855; 95% CI=0.743-0.984; p=0.029) after adjustment for multiple confounding factors. Conclusions: We showed that low DMP1 levels were significantly associated with presence of vascular calcification, and were independently associated with the incident cardiovascular events in prevalent peritoneal dialysis patients. DMP1 might be considered the novel factor that contributing the pathophysiology of cardiovascular disease in dialysis patients.

The Effect of Post-Fabrication Annealing on an Amorphous IGZO Visible-Light Photodetector

Park, Yongkook,Park, Hyung-Youl,Kang, Dong-Ho,Kim, Gwang-Sik,Lim, Donghwan,Yu, Hyun-Yong,Choi, Changhwan,Park, Jin-Hong American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11

<P>We demonstrate the effect of the thermal annealing temperature (250 and 300 degrees C) on the performance (photosensitivity and temporal photoresponse) of an amorphous indium-gallium-zinc-oxide (alpha-IGZO) photodetector based on the TFT structure to visible radiation. Analysis of photosensitivity was performed to assess various sensing parameters, such as photoresponsivity (R-ph), threshold voltage (V-TH) shift, and subthreshold swing (SS). The photosensitivity was improved as the wavelength of light decreased and the annealing temperature increased. This was analyzed based on the activation energy for the ionization of an oxygen vacancy (V-o) and the concentration of Vo in relation to the thermal annealing condition. The temporal photoresponse of the alpha-IGZO device are also presented. The photoresponse times improved as the annealing temperature increased, which was due to the increase in the concentration of V-o functioning as a generation and recombination center with increasing annealing temperature.</P>