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- 저자 : Sang Youp Hwang (검색결과 22 건)
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安旼燁,黃尙勉,鄭在灌 成均館大學校 科學技術硏究所 1998 論文集 Vol.49 No.1
In this study in order to remove 3,5-dimethylphenol from aqueous solutions the granular activated carbon, SLS-100, manufactured by Sam-Chul-Li Company, was used as an adsorbent. The adsorption time to reach equilibrium and the effects of activated carbon size, temperature, and pH were analyzed. Finally adsorption isotherms for various sizes of activated carbon were examined at optimum pH. 1. The adsorption capacity of activated carbon in the size range (-20∼50/60 mesh) of this study was highest at 50/60 mesh size and the equilibriium time for the adsorption of 3,5-dimethylphenol was found 10 days. 2. The maximum adsorption took place at the lowest temperature of 5℃ in the temperature range (5∼50℃) of this investigation. 3. The activated carbon (35/40 mesh) showed its maximum adsorption capacity at pH 7. 4. The Langmuir isotherm as well as the Freundlich isotherm agreed well with the experimental data in the concentration range (1∼80 mg/l) of this experiment, although the Langmuir isotherm showed a little better agreement than Freundlich isotherm.
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황상엽(Hwang, Sang-Youp),하흥용(Ha, Heung-Yong) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.11
본 연구에서는 소형 카트용 스택제작에 사용하기 위한 분리판에 관한 연구를 진행하였다. 분리판의 두께가 감소해야 스택의 부피를 줄이고 출력밀도를 높일 수 있기 때문에 분리판 두께 감소를 위한 채널의 깊이 최적화 실험을 진행하였다. 이를 위해 캐소드 채널 깊이에 따른 DMFC 성능의 변화를 관찰하기 위해 캐소드 채널의 깊이를 0.3mm에서부터 1.0mm로 변화시켰다. 채널깊이가 0.5mm일 때 가장 좋은 성능을 보였는데, 원인으로는 단면적 감소에 의한 선속도의 증가와 내부 압력증가를 들 수 있다. 채널깊이 변화에 따른 영향을 분석하기 위해 마노미터를 이용하여 차압을 측정하였고, 임피던스 분석법을 통해 전극의 저항을 측정하였다.
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Oncologic outcomes after radical surgery for periampullary cancer in octogenarians
Sung Hyun Kim,Jae Uk Chong,Jin Hong Lim,Moon Jae Chung,Jeong Youp Park,Seung Min Bang,Seung Woo Park,Ho Kyung Hwang,Chang Moo Kang,Woo Jung Lee,Kyung Sik Kim 한국간담췌외과학회 2018 Annals of hepato-biliary-pancreatic surgery Vol.22 No.2
Backgrounds/Aims: Interest in treatments for elderly patients has increased with life expectancy, and various studies have reported on the safety and feasibility of radical surgery in elderly patients with cancer. Here, we investigated oncologic outcomes of periampullary cancer in octogenarians. Methods: We retrospectively reviewed medical records of 68 patients over 80 years of age who were diagnosed with periampullary cancer and were eligible for surgery; we analyzed overall survival (OS) and immediate postoperative complications and mortality. Results: There were no significant differences in mean age, disease type, oncologic features, comorbidities, or nutritional status between the patients who had surgery and those who did not. Five patients (20.0%) had major postoperative complications, but there was no immediate postoperative mortality. Patients who had surgery (n=25) had better OS (29.3 months; 95% confidence interval [CI]: 5.6-53.0) than did those who did not (n=43, OS: 7.6 months; 95% CI: 3.2-12.0 months; p <0.001). Similarly, patients with distal common bile duct cancer who underwent surgery had better OS than those who did not (surgery group: n=13, OS: 29.3 months, 95% CI: 8.9-49.7; non-surgery group: n=15, OS: 5.7 months, 95% CI: 4.2-7.2 months; p=0.002). Conclusions: Radical surgery for octogenarian patients with periampullary cancer is safe, feasible, and expected to result in better survival outcomes, especially for patients with common bile duct cancer.
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Hwang, Hyeon Seok,Yang, Keum Jin,Park, Ki Cheol,Choi, Hyun Soo,Kim, So Hee,Hong, Sung Youp,Jeon, Byeong Hwa,Chang, Yoon Kyung,Park, Cheol Whee,Kim, Suk Young,Lee, Sang Ju,Yang, Chul Woo Oxford University Press 2013 Nephrology, dialysis, transplantation Vol.28 No.5
<P><B>Background</B></P><P>The effect of paricalcitol on renal ischemia–reperfusion injury (IRI) has not been investigated. We examined whether paricalcitol is effective in preventing inflammation in a mouse model of IRI, and evaluated the cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) pathways as a protective mechanism of paricalcitol.</P><P><B>Methods</B></P><P>Paricalcitol (0.3 μg/kg) was administered to male C57BL/6 mice 24 h before IRI. Bilateral kidneys were subjected to 23 min of ischemia, and mice were killed 72 h after IRI. The effects of paricalcitol on renal IRI were evaluated in terms of renal function, tubular necrosis, apoptotic cell death, inflammatory cell infiltration and inflammatory cytokines. The effects of paricalcitol on COX-2, PGE2 and its receptors were investigated.</P><P><B>Results</B></P><P>Paricalcitol pretreatment improved renal function (decreased blood urea nitrogen and serum creatinine levels), tubular necrosis and apoptotic cell death in IRI-mice kidneys. The infiltration of inflammatory cells (T cells and macrophages), and the production of proinflammatory cytokines (RANTES, tumor necrosis factor-α, interleukin-1β and interferon-γ) were reduced in paricalcitol-treated mice with IRI. Paricalcitol up-regulated COX-2 expression, PGE2 synthesis and mRNA expression of receptor subtype EP4 in post-ischemic renal tissue. The cotreatment of a selective COX-2 inhibitor with paricalcitol restored functional injury and tubular necrosis in paricalcitol-treated mice with IRI.</P><P><B>Conclusions</B></P><P>Our study demonstrates that paricalcitol pretreatment prevents renal IRI via the inhibition of renal inflammation, and the up-regulation of COX-2 and PGE2 is one of the protective mechanisms of paricalcitol in renal IRI.</P>
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Ji‑Hyun Kim,Sang Youp Hwang,Jung Eun Park,Gi Bbum Lee,Ho Kim,Seokhwi Kim,Bum Ui Hong 한국탄소학회 2019 Carbon Letters Vol.29 No.3
To prepare activated carbon with a high specific surface area, oxygen functional groups (OFGs) that can serve as useful electron donors during KOH activation were treated with nitric acid and incorporated into activated carbon. OFGs are incorporated differently according to the surface characteristics of starting materials. Up to 22.46% OFGs are incorporated into wood-based activated carbons (WACs), the C=O, COOH contents was 1.90, 17.05%, respectively. Whereas up to 12.82% OFGs are incorporated into coconut shell-based activated carbons, the C=O, COOH contents was 4.12, 6.15%, respectively. The OFGs used for increasing the specific surface area are the carbonyl group, and as the content of the functional group increases, the carbonyl group spreads to the carboxyl group. The specific surface area of activated carbons increased by 10–68% with an increase in the carbonyl group up to 6% (maximum point of carbonyl group). On the other hand, the specific surface area for WACs increased when the carboxyl group was 10% or below, but decreased by 6–15% when it increased to 10% or excess.
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Diagnostic Performance of Angiography-Derived FFR According to the Analysis Factors
You-Jeong Ki,Doyeon Hwang,Seokhun Yang,Sang-Hoon Na,Joon-Hyung Doh,Chang-Wook Nam,Doo-Youp Kim,Byung-Joo Choi,Chang-Bae Sohn,Hyun-Jong Lee,Hyun Kuk Kim,Yongcheol Kim,Eun-Seok Shin,Bon-Kwon Koo 대한심장학회 2026 Korean Circulation Journal Vol.56 No.2
Background and ObjectivesQuantitative flow ratio (QFR) is a method for estimating fractional flow reserve (FFR) without the use of an invasive pressure wire or hyperemic agent. However, the reasons for variation in QFR accuracy across studies and the factors associated with its accuracy remain unclear. The aim of this study was to investigate the diagnostic performance of QFR under different clinical and analysis conditions. MethodsThis multicenter trial prospectively enrolled patients undergoing coronary angiography with an indication for invasive FFR. The composite score for the QFR analysis factors was calculated based on the presence or absence of the angiographic factor, system factor, lesion factor, and subjective difficulty factor. The diagnostic performance of the QFR was assessed for each composite score using FFR ≤0.80 as the reference. ResultsA total of 285 vessels from 239 patients were analyzed. The median FFR and QFR values were 0.83 (interquartile range [IQR], 0.78–0.88) and 0.83 (IQR, 0.76–0.89), respectively. Using FFR ≤0.80 as a reference, QFR showed an overall diagnostic accuracy of 81.4%. Higher composite scores were associated with lower diagnostic performance of QFR in predicting FFR ≤0.80 (p-for-trend=0.010). The diagnostic accuracy of QFR ranged from 94.1% in vessels with low composite scores to 73.7% in those with high composite scores. ConclusionsThe diagnostic accuracy of QFR decreases with increasing lesion complexity, system factors, lower angiographic image quality, and analysis difficulty. These findings suggest that specific lesion, system, and imaging-related factors can significantly impact the reliability of QFR in clinical practice.
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Effects of Galla chinensis extracts on UVB-irradiated MMP-1 production in hairless mice.
Sun, Zheng-wang,Hwang, Eunson,Lee, Hyun Ji,Lee, Tae Youp,Song, Hyun Geun,Park, Sang-Yong,Shin, Heon-Sub,Lee, Don-Gil,Yi, Tae Hoo Springer-Verlag Tokyo 2015 Journal of Natural Medicines Vol.69 No.1
<P>Galla chinensis (GAC) is a natural traditional Chinese medicine that has been widely used in folk medicine. Although GAC compounds (mainly gallic acid and methyl gallate) possess strong antiviral, antibacterial, anticancer, and antioxidant activities, there is no report regarding topical or oral administration of GAC compounds on UVB irradiation-induced photoaging in hairless mice (SKH: HR-1). In the present study, we examined cell viability, intracellular reactive oxygen species (ROS), matrix metalloproteinase-1 (MMP-1), and interleukin-6 (IL-6) in skin fibroblasts and keratinocytes induced by UVB in vitro. We also studied skin damage by measuring skin thickness, elasticity, wrinkling and levels of protein MMP-1, elastin, procollagen type I, and transforming growth factor-β1 (TGF-β1) in hairless mouse skin chronically irradiated by UVB in vivo. GAC treatment significantly prevented skin photoaging by reducing the levels of ROS, MMP-1, and IL-6 and promoting production of elastin, procollagen type I, and TGF-β1. According to the results of H&E staining and Masson's trichrome staining, GAC reduced skin thickness and wrinkle formation while it increased skin elasticity. The effects of GAC on UVB-induced skin photoaging may be due to suppressed MMP-1 expression. These findings could be referenced for the development of new agents that target UVB-induced photoaging.</P>
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Electrochemical Capacitance of Activated Carbons Regenerated using Thermal and Chemical Activation
Park, Jung Eun,Lee, Gi Bbum,Hwang, Sang Youp The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.3
Spent activated carbons (SACs) collected from a water treatment plant were regenerated and then adopted as electrochemical material in capacitors. The SACs used in this study were regenerated via two steps, namely thermal and chemical activation. However, during the activation process, the adsorbates were converted into ashes, which caused pore blockage and decreased specific surface area. The regenerated SACs were washed with acid solutions with different levels of acidity (strong: HCl, mild: H<sub>3</sub>PO<sub>4</sub>, and weak: H<sub>2</sub>O<sub>2</sub>) to remove the ashes. The regenerated SACs washed with HCl exhibited the highest specific surface area, although their capacitance was not the highest. Conversely, the specific surface area of regenerated SACs washed using H<sub>3</sub>PO<sub>4</sub> was slightly lower than that of HCl, but exhibited higher capacitance and electrochemical stability. Although the strong acid removed the generated ashes in the pores efficiently, it could adversely affect their structural stability, which would lead to lower capacitance.
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