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Dong-Chan Oh

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https://www.readbyqxmd.com/read/29219847/strong-enhancement-of-emission-efficiency-in-gan-light-emitting-diodes-by-plasmon-coupled-light-amplification-of-graphene
#1
Jong Min Kim, Sung Kim, Sung Won Hwang, Chang Oh Kim, Dong Hee Shin, Ju Hwan Kim, Chan Wook Jang, Soo Seok Kang, Euyheon Hwang, Suk-Ho Choi, Sherif H El-Gohary, Kyung Min Byun
Recently, we have demonstrated that excitation of plasmon-polaritons in a mechanically-derived graphene sheet on the top of a ZnO semiconductor considerably enhances its light emission efficiency. If this scheme is also applied to device structures, it is then expected that the energy efficiency of light-emitting diodes (LEDs) increases substantially and the commercial potential will be enormous. Here, we report that the plasmon-induced light coupling amplifies emitted light by ~1.6 times in doped large-area chemical-vapor-deposition-grown graphene, which is useful for practical applications...
December 8, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29182331/polyoxygenated-steroids-from-the-sponge-clathria-gombawuiensis
#2
Jung-Kyun Woo, Thi Kim Quy Ha, Dong-Chan Oh, Won-Keun Oh, Ki-Bong Oh, Jongheon Shin
Six new polyoxygenated steroids (1-6) along with clathriol (7) were isolated from the Korean marine sponge Clathria gombawuiensis. Based upon the results of combined spectroscopic analyses, the structures of gombasterols A-F (1-6) were elucidated to be those of highly oxygenated steroids possessing a 3β,4α,6α,7β-tetrahydroxy or equivalent (7β-sodium O-sulfonato for 3) substitution pattern and a C-15 keto group as common structural motifs. The relative and absolute configurations of these steroids, including the rare 14β configuration of 1-4, were determined by a combination of NOESY, J-based analyses, the 2-methoxy-2-(trifluoromethyl)phenylacetic acid (MTPA) method, and X-ray crystallographic analysis...
November 28, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/29174850/association-between-pepsin-in-the-saliva-and-the-subjective-symptoms-in-patients-with-laryngopharyngeal-reflux
#3
Ah Ra Jung, Oh Eun Kwon, Jung Min Park, Sung Hwa Dong, Su Young Jung, Young Chan Lee, Young-Gyu Eun
OBJECTIVES: Our study was designed to further evaluate the relationships between the saliva pepsin level and the symptoms and quality of life of patients with laryngopharyngeal reflux (LPR). STUDY DESIGN: A prospective cohort study without controls. SETTING: Tertiary teaching hospital. SUBJECTS AND METHODS: We analyzed 50 patients diagnosed with LPR by 24-hour multichannel intraluminal impedance pH monitoring. All subjects were instructed to collect saliva samples upon waking in the morning...
November 24, 2017: Journal of Voice: Official Journal of the Voice Foundation
https://www.readbyqxmd.com/read/29162885/an-increased-chloride-level-in-hypochloremia-is-associated-with-decreased-mortality-in-patients-with-severe-sepsis-or-septic-shock
#4
Hyung Jung Oh, Seung Jun Kim, Yong Chan Kim, Eun Jin Kim, In Young Jung, Dong Hyun Oh, Su Jin Jeong, Nam Su Ku, Sang Hoon Han, Jun Yong Choi, Young Goo Song, Dong-Ryeol Ryu, June Myung Kim
Only a few observational studies investigated the association between hypochloremia and mortality in critically ill patients, and these studies included small number of septic patients. Also, no study has evaluated the effect of an increase in chloride (Cl-) concentration in hypochloremia on the mortality. A total of 843 Korean septic patients were divided into three groups based on their baseline Cl- level, and Cox analyses were performed to evaluate the 28-day mortality. Moreover, the change in Cl- level (ΔCl) from baseline to 24, 48, or 72 hour was determined, and Cox analyses were also conducted to evaluate the relationship of ΔCl with mortality...
November 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29112406/nicrophorusamides-a-and-b-antibacterial-chlorinated-cyclic-peptides-from-a-gut-bacterium-of-the-carrion-beetle-nicrophorus-concolor
#5
Yern-Hyerk Shin, Suhyun Bae, Jaehoon Sim, Joonseong Hur, Shin-Il Jo, Jongheon Shin, Young-Ger Suh, Ki-Bong Oh, Dong-Chan Oh
Nicrophorusamides A and B (1 and 2) were discovered from a rare actinomycete, Microbacterium sp., which was isolated from the gut of the carrion beetle Nicrophorus concolor. The structures of the nicrophorusamides were established as new chlorinated cyclic hexapeptides bearing uncommon amino acid units mainly based on 1D and 2D NMR spectroscopic analysis. The absolute configurations of the amino acid residues 5-chloro-l-tryptophan, d-threo-β-hydroxyasparagine/d-asparagine, l-ornithine, l-allo-isoleucine, d-leucine, and d-valine were determined using Marfey's method and chemical derivatization with 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl isothiocyanate followed by LC/MS analysis...
November 7, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/29096790/reverse-j-curve-relationship-between-on-treatment-blood-pressure-and-mortality-in-patients-with-heart-failure
#6
Sang Eun Lee, Hae-Young Lee, Hyun-Jai Cho, Won-Seok Choe, Hokon Kim, Jin-Oh Choi, Eun-Seok Jeon, Min-Seok Kim, Kyung-Kuk Hwang, Shung Chull Chae, Sang Hong Baek, Seok-Min Kang, Dong-Ju Choi, Byung-Su Yoo, Kye Hun Kim, Myeong-Chan Cho, Jae-Joong Kim, Byung-Hee Oh
OBJECTIVES: This study aimed to assess the relationship between on-treatment blood pressure (BP) and clinical outcomes of patients with heart failure (HF). BACKGROUND: Lower BP has been reported to be related to increased mortality in various cardiovascular diseases. The optimal BP level for patients already experiencing HF is contentious. METHODS: The Korean Acute Heart Failure registry prospectively enrolled a total of 5,625 consecutive patients hospitalized for acute HF in 10 tertiary university hospitals in Korea between March 2011 and February 2014...
November 2017: JACC. Heart Failure
https://www.readbyqxmd.com/read/29090916/deinococcucins-a-d-aminoglycolipids-from-deinococcus-sp-a-gut-bacterium-of-the-carpenter-ant-camponotus-japonicus
#7
Bora Shin, So Hyun Park, Byung-Yong Kim, Shin-Il Jo, Sang Kook Lee, Jongheon Shin, Dong-Chan Oh
Four new aminoglycolipids, deinococcucins A-D (1-4), were discovered from a Deinococcus sp. strain isolated from the gut of queen carpenter ants, Camponotus japonicus. The structures of deinococcucins A-D were elucidated as a combination of N-acetyl glucosamine, 2,3-dihydroxypropanoic acid, and an alkyl amine with a C16 or C17 hydrocarbon chain primarily based on 1D and 2D NMR and mass spectroscopic data. The exact location of the olefinic double bond in deinococcucins C and D (3 and 4) was assigned based on the liquid chromatography-mass spectroscopy data obtained after olefin metathesis...
November 1, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/29079633/hyponatraemia-and-its-prognosis-in-acute-heart-failure-is-related-to-right-ventricular-dysfunction
#8
Heesun Lee, Sang Eun Lee, Chan Soon Park, Jin Joo Park, Ga Yeon Lee, Min-Seok Kim, Jin-Oh Choi, Hyun-Jai Cho, Hae-Young Lee, Dong-Ju Choi, Eun-Seok Jeon, Jae-Joong Kim, Byung-Hee Oh
OBJECTIVES: Hyponatraemia is a well-known predictor of clinical outcomes in heart failure (HF). However, the mechanism remains poorly understood. Previous reports suggest that hyponatraemia is related to right HF. We sought to evaluate the association between right ventricular (RV) dysfunction and hyponatraemia, and the impact of this relationship on the prognosis of patients with acute heart failure (AHF). METHODS: This is a nested case-control study of the Korean Acute Heart Failure registry...
October 27, 2017: Heart: Official Journal of the British Cardiac Society
https://www.readbyqxmd.com/read/29070814/persistent-elevation-of-postoperative-neutrophil-to-lymphocyte-ratio-a-better-predictor-of-survival-in-gastric-cancer-than-elevated-preoperative-neutrophil-to-lymphocyte-ratio
#9
Kyueng-Whan Min, Mi Jung Kwon, Dong-Hoon Kim, Byoung Kwan Son, Eun-Kyung Kim, Young Ha Oh, Young Chan Wi
Postoperative neutrophil-to-lymphocyte ratio change (NLRc) reflects the dynamic change of balance between host inflammatory response and immune response after treatment. In gastric cancer, an elevated initial NLR (iNLR) is reported to be a prognostic predictor, but the clinical application of the NLRc remains unclear. The NLRc was assessed in 734 patients undergoing total/subtotal gastrectomy and endoscopic submucosal dissection for gastric adenocarcinoma. The iNLR and NLRc were recorded within 10 days of the first diagnosis and 3-6 months after surgery, respectively...
October 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29061303/unique-binding-mode-of-evogliptin-with-human-dipeptidyl-peptidase-iv
#10
Hyung Ki Lee, Mi-Kyung Kim, Ha Dong Kim, Heung Jae Kim, Ji Won Kim, Jie-Oh Lee, Chan-Wha Kim, Eunice EunKyeong Kim
Evogliptin ((R)-4-((R)-3-amino-4-(2,4,5-trifluorophenyl)butanoyl)-3-(tert-butoxymethyl) piperazine-2-one)) is a highly potent selective inhibitor of dipeptidyl peptidase IV (DPP4) that was approved for the treatment of type 2 diabetes in South Korea. In this study, we report the crystal structures of Evogliptin, DA-12166, and DA-12228 (S,R diastereomer of Evogliptin) complexed to human DPP4. Analysis of both the structures and inhibitory activities suggests that the binding of the trifluorophenyl moiety in the S1 pocket and the piperazine-2-one moiety have hydrophobic interactions with Phe357 in the S2 extensive subsite, and that the multiple hydrogen bonds made by the (R)-β-amine group in the S2 pocket and the contacts made by the (R)-tert-butyl group with Arg125 contribute to the high potency observed for Evogliptin...
October 20, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28982721/outcomes-of-de-novo-and-acute-decompensated-heart-failure-patients-according-to-ejection-fraction
#11
Ki Hong Choi, Ga Yeon Lee, Jin-Oh Choi, Eun-Seok Jeon, Hae-Young Lee, Hyun-Jai Cho, Sang Eun Lee, Min-Seok Kim, Jae-Joong Kim, Kyung-Kuk Hwang, Shung Chull Chae, Sang Hong Baek, Seok-Min Kang, Dong-Ju Choi, Byung-Su Yoo, Kye Hun Kim, Hyun-Young Park, Myeong-Chan Cho, Byung-Hee Oh
OBJECTIVE: There are conflicting results among previous studies regarding the prognosis of heart failure with preserved ejection fraction (HFpEF) compared with heart failure with reduced ejection fraction (HFrEF). This study aimed to compare the outcomes of patients with de novo acute heart failure (AHF) or acute decompensated HF (ADHF) according to HFpEF (EF≥50%), or HFrEF (EF<40%) and to define the prognosis of patients with HF with mid-range EF (HFmrEF, 40≤EF<50%). METHODS: Between March 2011 and February 2014, 5625 consecutive patients with AHF were recruited from 10 university hospitals...
October 5, 2017: Heart: Official Journal of the British Cardiac Society
https://www.readbyqxmd.com/read/28960033/evaluation-of-the-efficacy-and-safety-of-da-9601-versus-its-new-formulation-da-5204-in-patients-with-gastritis-phase-iii-randomized-double-blind-non-inferiority-study
#12
Yoon Jin Choi, Dong Ho Lee, Myung Gyu Choi, Sung Joon Lee, Sung Kook Kim, Geun Am Song, Poong Lyul Rhee, Hwoon Yong Jung, Dae Hwan Kang, Yong Chan Lee, Si Hyung Lee, Suck Chei Choi, Ki Nam Shim, Sang Yong Seol, Jeong Seop Moon, Yong Woon Shin, Hyun Soo Kim, Soo Teik Lee, Jin Woong Cho, Eun Kwang Choi, Oh Young Lee, Jin Seok Jang
This study compared the efficacy of DA-9601 (Dong-A ST Co., Seoul, Korea) and its new formulation, DA-5204 (Dong-A ST Co.), for treating erosive gastritis. This phase III, randomized, multicenter, double-blind, non-inferiority trial randomly assigned 434 patients with endoscopically proven gastric mucosal erosions into two groups: DA-9601 3 times daily or DA-5,204 twice daily for 2 weeks. The final analysis included 421 patients (DA-5204, 209; DA-9601, 212). The primary endpoint (rate of effective gastric erosion healing) and secondary endpoints (cure rate of endoscopic erosion and gastrointestinal [GI] symptom relief) were assessed using endoscopy after the treatment...
November 2017: Journal of Korean Medical Science
https://www.readbyqxmd.com/read/28955391/relation-of-renal-function-with-left-ventricular-systolic-function-and-nt-probnp-level-and-its-prognostic-implication-in-heart-failure-with-preserved-versus-reduced-ejection-fraction-an-analysis-from-the-korean-heart-failure-korhf-registry
#13
Chan Soon Park, Jin Joo Park, Il-Young Oh, Chang-Hwan Yoon, Dong-Ju Choi, Hyun-Ah Park, Seok-Min Kang, Byung-Su Yoo, Eun-Seok Jeon, Jae-Joong Kim, Myeong-Chan Cho, Shung Chull Chae, Kyu-Hyung Ryu, Byung-Hee Oh
BACKGROUND AND OBJECTIVES: The relationship between ejection fraction (EF), N-terminal pro-brain natriuretic peptide (NT-proBNP) levels and renal function is unknown as stratified by heart failure (HF) type. We investigated their relation and the prognostic value of renal function in heart failure with preserved ejection fraction (HFpEF) vs. reduced ejection fraction (HFrEF). MATERIALS AND METHODS: NT-proBNP, glomerular filtration rate (GFR), and EF were obtained in 1,932 acute heart failure (AHF) patients...
September 2017: Korean Circulation Journal
https://www.readbyqxmd.com/read/28955381/korean-guidelines-for-diagnosis-and-management-of-chronic-heart-failure
#14
REVIEW
Min-Seok Kim, Ju-Hee Lee, Eung Ju Kim, Dae-Gyun Park, Sung-Ji Park, Jin Joo Park, Mi-Seung Shin, Byung Su Yoo, Jong-Chan Youn, Sang Eun Lee, Sang Hyun Ihm, Se Yong Jang, Sang-Ho Jo, Jae Yeong Cho, Hyun-Jai Cho, Seonghoon Choi, Jin-Oh Choi, Seong Woo Han, Kyung Kuk Hwang, Eun Seok Jeon, Myeong-Chan Cho, Shung Chull Chae, Dong-Ju Choi
The prevalence of heart failure (HF) is skyrocketing worldwide, and is closely associated with serious morbidity and mortality. In particular, HF is one of the main causes for the hospitalization and mortality in elderly individuals. Korea also has these epidemiological problems, and HF is responsible for huge socioeconomic burden. However, there has been no clinical guideline for HF management in Korea. 
The present guideline provides the first set of practical guidelines for the management of HF in Korea and was developed using the guideline adaptation process while including as many data from Korean studies as possible...
September 2017: Korean Circulation Journal
https://www.readbyqxmd.com/read/28954937/dna-topoisomerase-inhibitory-activity-of-constituents-from-the-fruits-of-illicium-verum
#15
Tae In Kim, Bora Shin, Geum Jin Kim, Hyukjae Choi, Chong Soon Lee, Mi Hee Woo, Dong-Chan Oh, Jong Keun Son
Three new compounds, a sesquilignan (1) and two glucosylated phenylpropanoids (2, 3), and seven known compounds (4-10), were isolated from the fruits of Illicium verum Hook. Fil. (Illiciaceae). The structures of 1-3 were determined based on one and two dimensional (1D- and 2D-) NMR data and ECD spectra analyses. Compounds 3, 5, 6, and 8-10 exhibited potent inhibitory activities against topoisomerase II with IC50 values of 54.6, 25.5, 17.9, 12.1, 0.3 and 1.0 μM, respectively, compared to etoposide, the positive control, with an IC50 of 43...
September 26, 2017: Chemical & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/28950443/current-cytology-practices-in-korea-a-nationwide-survey-by-the-korean-society-for-cytopathology
#16
Eun Ji Oh, Chan Kwon Jung, Dong-Hoon Kim, Han Kyeom Kim, Wan Seop Kim, So-Young Jin, Hye Kyoung Yoon
BACKGROUND: Limited data are available on the current status of cytology practices in Korea. This nationwide study presents Korean cytology statistics from 2015. METHODS: A nationwide survey was conducted in 2016 as a part of the mandatory quality-control program by the Korean Society for Cytopathology. The questionnaire was sent to 208 medical institutions performing cytopathologic examinations in Korea. Individual institutions were asked to submit their annual cytology statistical reports and gynecologic cytology-histology correlation data for 2015...
November 2017: Journal of Pathology and Translational Medicine
https://www.readbyqxmd.com/read/28923305/risk-factors-for-mortality-in-patients-with-low-lactate-level-and-septic-shock
#17
Dong Hyun Oh, Moo Hyun Kim, Woo Yong Jeong, Yong Chan Kim, Eun Jin Kim, Je Eun Song, In Young Jung, Su Jin Jeong, Nam Su Ku, Jun Yong Choi, Young Goo Song, June Myung Kim
BACKGROUND: According to the new definition of septic shock, vasopressor therapy and hyperlactatemia are essential for diagnosis. However, there is controversy regarding the cutoff value for lactate, and prognostic factors in patients with septic shock and hypolactatemia. This study evaluated the prognostic significance of the cutoff value for lactate level in septic shock patients. METHODS: The retrospective observational cohort study enrolled 1043 patients aged ≥18 years who meet the revised definition of septic shock...
August 26, 2017: Journal of Microbiology, Immunology, and Infection, Wei Mian Yu Gan Ran za Zhi
https://www.readbyqxmd.com/read/28919126/low-dose-ct-for-the-diagnosis-of-appendicitis-in-adolescents-and-young-adults-locat-a-pragmatic-multicentre-randomised-controlled-non-inferiority-trial
#18
(no author information available yet)
BACKGROUND: CT radiation is arguably carcinogenic. Results from single-centre studies, mostly retrospective, have advocated lowering the CT radiation dose for the diagnosis of appendicitis. However, adoption of low-dose CT has been slow. We aimed to assess the effectiveness of low-dose CT compared with standard-dose CT in the diagnosis of appendicitis in adolescents and young adults. METHODS: We did this pragmatic, multicentre, randomised controlled non-inferiority trial at 20 South Korean teaching hospitals with little experience with low-dose CT...
November 2017: Lancet. Gastroenterology & Hepatology
https://www.readbyqxmd.com/read/28903000/structural-revision-of-baulamycin-a-and-structure-activity-relationships-of-baulamycin-a-derivatives
#19
Sandip Sengupta, Munhyung Bae, Dong-Chan Oh, Uttam Dash, Hak Joong Kim, Woon Young Song, Injae Shin, Taebo Sim
Total synthesis of the proposed structure of baulamycin A was performed. The spectral properties of the synthetic compound differ from those reported for the natural product. On the basis of comprehensive NMR study, we proposed two other possible structures for natural baulamycin A. Total syntheses of these two substances were performed, which enabled assignment of the correct structure of baulamycin A. Key features of the convergent and fully stereocontrolled route include Evans Aldol and Brown allylation reactions to construct the left fragment, a prolinol amide-derived alkylation/desymmetrization to install the methyl-substituted centers in the right fragment, and finally, a Carreira alkynylation to join both fragments...
October 2, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28883215/cytokine-response-to-diet-and-exercise-affects-atheromatous-matrix-metalloproteinase-2-9-activity-in-mice
#20
Soo-Min Shon, Hee Jeong Jang, Dawid Schellingerhout, Jeong-Yeon Kim, Wi-Sun Ryu, Su-Kyoung Lee, Jiwon Kim, Jin-Yong Park, Ji Hye Oh, Jeong Wook Kang, Kang-Hoon Je, Jung E Park, Kwangmeyung Kim, Ick Chan Kwon, Juneyoung Lee, Matthias Nahrendorf, Jong-Ho Park, Dong-Eog Kim
BACKGROUND: The aim of this study is to identify the principal circulating factors that modulate atheromatous matrix metalloproteinase (MMP) activity in response to diet and exercise.Methods and Results:Apolipoprotein-E knock-out (ApoE(-/-)) mice (n=56) with pre-existing plaque, fed either a Western diet (WD) or normal diet (ND), underwent either 10 weeks of treadmill exercise or had no treatment. Atheromatous MMP activity was visualized using molecular imaging with a MMP-2/9 activatable near-infrared fluorescent (NIRF) probe...
September 25, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
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