Silibinin Inhibits Tumor Growth through Downregulation of Extracellular Signal-Regulated Kinase and Akt <i>in Vitro</i> and <i>in Vivo</i> in Human Ovarian Cancer Cells

Cho, Hyun Jin,Suh, Dong Soo,Moon, Soo Hyeon,Song, Yong Jung,Yoon, Man Soo,Park, Do Yoon,Choi, Kyung Un,Kim, Yong Keun,Kim, Ki Hyung American Chemical Society 2013 Journal of agricultural and food chemistry Vol.61 No.17

<P>Anticancer activity of silibinin, a flavonoid, has been demonstrated in various cancer cell types. However, the underlying mechanisms were not elucidated in human ovarian cancer cells. The present study was undertaken to examine the effect of silibinin <I>in vitro</I> and <I>in vivo</I> on tumor growth in human ovarian cancer cells. Silibinin decreased cell viability in a dose- and time-dependent manner. Silibinin caused an increase in reactive oxygen species (ROS) generation, and the silibinin-induced cell death was prevented by the antioxidant <I>N</I>-acetylcysteine (NAC). Western blot analysis showed silibinin-induced downregulation of extracellular signal-regulated kinase (ERK) and Akt. Transfection of constitutively active forms of MEK and Akt prevented the silibinin-induced cell death. Oral administration of silibinin in animals with subcutaneous A2780 cells reduced tumor volume. Subsequent tumor tissue analysis showed that silibinin treatment induced a decrease in Ki-67-positive cells, an increase in transferase-mediated dUTP nick end labeling (TUNEL)-positive cells, activation of caspase-3, and inhibition of p-ERK and p-Akt. These results indicate that silibinin reduces tumor growth through inhibition of ERK and Akt in human ovarian cancer cells. These data suggest that silibinin may serve as a potential therapeutic agent for human ovarian cancers.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2013/jafcau.2013.61.issue-17/jf400192v/production/images/medium/jf-2013-00192v_0008.gif'></P>

Scalable video coding with large block for UHD video

Un-Ki Park,Haechul Choi,Jung Won Kang,Jae-Gon Kim IEEE 2012 IEEE transactions on consumer electronics Vol.58 No.3

<P>Ultra-high definition (UHD) which has 4 to 16 times as many pixels as existing high definition (HD) is expected as a next generation video format. To deliver UHD and HD videos simultaneously in the communications-broadcasting convergence environment, scalable video coding (SVC) is a highly attractive solution. We propose an improved scalable video coding method to achieve high coding efficiency particularly for UHD and HD videos. The basic idea is to allow large block size beyond the block size of 16×16 pixels in H.264/AVC SVC, which results in more efficient inter-layer prediction and syntax elements coding. The experimental results show that it achieves an average 5.34% reduction in BD-rate relative to H.264/AVC SVC.</P>

Role of Nitric Oxide in the Pathogenesis of Diabetic Nephropathy in Streptozotocin - Induced Diabetic Rats

(Ki Chul Choi),(Seong Cheol Lee),(Soo Wan Kim),(Nam Ho Kim),(Jong Un Lee),(Young Joon Kang) 대한내과학회 1999 The Korean Journal of Internal Medicine Vol.14 No.1

N/A Objectives: Several reports suggest that enhanced generation or actions of nitric oxide (NO) have been implicated in the pathogenesis of glomerular hyperfiltration and hyperperfusion that occurs in early diabetes. However, the precise role of altered NO generation in the pathogenesis of diabetic nephropathy is unclear. The present study was aimed at investigating the role of nitric oxide in the pathogenesis of glomerular hyperfiltration and hyperperfusion in streptozotocin-induced diabetic rats. Methods : To evaluate the role of NO in diabetic hyperfiltration, we measured plasma and urine concentrations of NO2-/NO3-, stable metabolic products of NO and protein expressions of three isoforms of nitric oxide synthase (NOS) in streptozotocin-induced diabetic rats. We also investigated renal hemodynamic changes, such as glomerular filtration rate (GFR) and renal plasma flow (RPF), in responses to acute and chronic administration of NO synthesis inhibitor, nitro-L-arginine methyl ester (L-NAME), in diabetic and control rats. Results : Diabetic rats exhibited significantly elevated plasma and urinary NO2-/NO3- levels at 28 days after streptozotocin injection, and total excretion of NO2-/NO3- was approximately five-fold higher in diabetic rats than controls. Insulin and L-NAME treatment prevented the increases in plasma and urinary NO2-/NO3- concentrations in diabetic rats, respectively. The three isoforms of NOS (bNOS, iNOS, and ecNOS) were all increased in the renal cortex, whereas they remained unaltered in the renal medulla at day 28. GFR and RPF were significantly elevated in diabetic rats, and acute and chronic inhibition of NO synthesis by L-NAME attenuated the renal hemodynamic changes (increases in GFR and RPF) in diabetic rats, respectively. Conclusions : NO synthesis was increased due to enhanced NOS expression in diabetic rats, and chronic NO blockade attenuated renal hyperfiltration and hyperperfusion in diabetic rats. In addition, diabetic rats exhibited enhanced renal hemodynamic responses to acute NO inhibition and excreted increased urinary NO2-/NO3-. These results suggest that excessive NO production may contribute to renal hyperfiltration and hyperperfusion in early diabetes.

Characteristics of a Corona between a Wiring Clamp (Dead End Clamp) and a Porcelain Insulator Used in a 154[㎸] Power Receptacle

Un-Ki Han,Jong-Min Kim,Sun-Bae Bang,Han-Sang Kim,Hyeong-Jun Choi 한국조명·전기설비학회 2007 조명·전기설비학회논문지 Vol.21 No.9

The occurrence of a corona is that electrical discharge due to the heterogeneity that occurs when an electrical field is concentrated in an electrode due to a cusp formed on said electrode. Wire treatment at the end of a 154[㎸] dead end clamp for end users accelerates the occurrence of corona, which in tum leads to power loss and noise. In this study, the characteristics of the corona which occurs between porcelain insulators and support clamps of overhead lines used in 154[㎸] power receiving facilities for end users were investigated. The corona, which cannot be identified by one common method, was measured utilizing a IN image carrera A risk assessment for fire damage and its status was suggested. The stress distribution of the electrical field by length of bare wire was suggested by means of the finite element method (FEMLAB). As a result, it was found to affect a porcelain insulators. These results can be utilized for the enhancement of clamp installation and safety in power facilities.

Medical Image Verification Watermarking for Healthcare Information Management

Choi, Un-Sook,Lee, Suk-Hwan,Kwon, Ki-Ryong Korea Multimedia Society 2017 The journal of multimedia information system Vol.4 No.4

This paper presents a verification watermarking applied to healthcare information management. The proposed method uses the whole region based on the public-key cryptograph, which is transformed by the DWT transform to integrity verification. Furthermore, the public-key cryptograph algorithm is used for the embedded watermark image. We adaptively select the upper bit-plane including the LSB parts of each block when the watermark is inserted.

A Study on the Level of Emotional Labor among Opticians in Incheon

Ki-Sung Kim,Sun-Kyung Kim,Mi-A Son,Hong-Gab Choi,Seung-Un Jin,Hyo-Jin Kim 대한시과학회 2017 대한시과학회지 Vol.19 No.3

목적 : 본 연구는 안경사의 감정노동 수준을 파악하여 감정노동에 대한 대책마련을 위한 기초자료를 제공 하고자 한다. 방법 : 인천지역 안경사가 응답한 80부의 설문지를 분석하였다. 감정노동의 측정도구는 Morris와 Feldman이 개발하고 김민주가 번역한 것을 안경사에 맞게 수정하였다. 결과 : 안경사의 감정노동 수준은 평균 3.24±0.55점이었다. 이는 같은 보건직종인 간호사(3.37±0.56) 및 치과위생사(3.28±0.56)와 비슷한 수준이었다. 그러나 생활지도원(2.72±0.55)과 버스기사(3.03±0.78) 보다 상대적으로 높았으며 콜센터직원(3.42±0.62)과 호텔종사자(3.60±0.99)보다 상대적으로 낮았다. 감정 노동의 하위항목인 감정표현의 빈도, 감정표현 규범의 주의성, 감정의 부조화 점수는 각각 3.64±0.63점, 3.11±0.59점, 2.98±0.70점이었다. 대상자의 주 당 평균 근로시간은 65.6±9.6시간이었고, 일일 근로시간 이 10시간 이하 및 10시간 초과인 경우 각각 2.94±0.42점과 3.34±0.55점이었다(p=0.005). 또한 주간 근 무일수가 5일 이하(2.99±0.54)와 5일 초과(3.31±0.53) 사이에는 유의한 차이가 있었다(p=0.032). 결론 : 안경사의 감정노동은 하루 근무시간이 10시간 이상일 때 더 높은 수준으로 나타났다. 따라서 감정 노동에 영향을 끼치는 요인을 찾아 근로환경을 개선하고 감정노동을 줄이기 위한 추가적인 연구가 필요하다. Purpose: The objective of this study was to evaluate the level of emotional labor in opticians in order to provide basic data. Methods: Survey of 80 questionnaires was carried out by opticians in Incheon. The questionnaire for emotional labor proposed by Morris and Feldman and translated by Min-Ju Kim was modified for opticians. Results: The mean level of emotional labor in opticians was 3.24±0.55 points. The level was similar to that of nurses(3.37±0.56) and dental hygienists(3.28±0.56) who belong to health service. However, it was relatively higher than that of life instructors(2.72±0.55) and bus drivers(3.03± 0.78), and was relatively lower than that of call center employees(3.42±0.62) and hotel workers (3.60±0.99). Labor point of its sub-criteria, frequency of emotional expression, attention of emotional expression norms and disharmony of emotion was 3.64±0.63, 3.11±0.59 and 2.98±0.70, respectively. It was shown that average working time per week of the participants was 65.6±9.6 hours, and the daily working hours of less than 10 hours and more than 10 hours were 2.94±0.42 and 3.34±0.55(p=0.005), respectively. In addition, there was a significant difference between less than 5 days(2.99±0.54) and more than 5 days(3.31±0.53) according to weekly working days(p =0.032). Conclusion: Opticians who works more than 10 hours per day (compared to less than 10 hours) showed higher level of emotional labor. Therefore, further study would be necessary to find out factors affecting emotional labor to improve their working conditions, and to reduce emotional labor.

Manufacturing strategy for a powder-based Fe-6.5%Si steel by powder rolling

Ki Hyuk Kwon,Yong Seok Choi,Do Hee Kim,Un-Gyeong Baek,Min-Ho Kwon,Eon Sik Lee 한국자기학회 2022 한국자기학회 학술연구발표회 논문개요집 Vol.31 No.2

Composition-Controlled PtCo Alloy Nanocubes with Tuned Electrocatalytic Activity for Oxygen Reduction

Choi, Sang-Il,Lee, Su-Un,Kim, Woo Youn,Choi, Ran,Hong, Kwangwoo,Nam, Ki Min,Han, Sang Woo,Park, Joon T. American Chemical Society 2012 ACS APPLIED MATERIALS & INTERFACES Vol.4 No.11

<P>Modification of the electronic structure and lattice contraction of Pt alloy nanocatalysts through control over their morphology and composition has been a crucial issue for improving their electrocatalytic oxygen reduction reaction (ORR) activity. In the present work, we synthesized PtCo alloy nanocubes with controlled compositions (Pt<SUB><I>x</I></SUB>Co NCs, <I>x</I> = 2, 3, 5, 7, and 9) by regulating the ratio of surfactants and the amount of Co precursor to elucidate the effect of the composition of nanocatalysts on their ORR activity. Pt<SUB><I>x</I></SUB>Co NCs had a Pt-skin structure after electrochemical treatment. The electrocatalysis experiments revealed a strong correlation between ORR activity and Co composition. Pt<SUB>3</SUB>Co NCs exhibited the best ORR performance among the various Pt<SUB><I>x</I></SUB>Co NCs. From density functional theory calculations, a typical volcano-type relationship was established between ORR activity and oxygen binding energy (<I>E</I><SUB>OB</SUB>) on NC surfaces, which showed that Pt<SUB>3</SUB>Co NCs had the optimal <I>E</I><SUB>OB</SUB> to achieve the maximum ORR activity. X-ray photoelectron spectroscopy and X-ray diffraction measurements demonstrated that the electronic structure and lattice contraction of the Pt<SUB><I>x</I></SUB>Co NCs could be tuned by controlling the composition of NCs, which are highly correlated with the trends of <I>E</I><SUB>OB</SUB> change.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2012/aamick.2012.4.issue-11/am301824w/production/images/medium/am-2012-01824w_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am301824w'>ACS Electronic Supporting Info</A></P>

Attenuated Central Pressor Response to Nitric Oxide Synthesis Inhibition in Chronic Renal Failure Rats

( Ki Chul Choi ),( Mee Hye Jung ),( Jong Un Lee ),( Soo Wan Kim ),( Nam Ho Kim ),( Young Joon Kang ) 대한내과학회 1997 The Korean Journal of Internal Medicine Vol.12 No.1

Characteristics of a Corona between a Wiring Clamp (Dead End Clamp) and a Porcelain Insulator Used in a 154[kV] Power Receptacle

Un-Ki Han,Jong-Min Kim,Sun-Bae Bang,Han-Sang Kim,Hyeong-Jun Choi 한국조명.전기설비학회 2007 조명·전기설비학회논문지 Vol.21 No.9

The occurrence of a corona is that electrical discharge due to the heterogeneity that occurs when an electrical field is concentrated in an electrode due to a cusp formed on said electrode. Wire treatment at the end of a 154[kV] dead end clamp for end users accelerates the occurrence of corona, which in turn leads to power loss and noise. In this study, the characteristics of the corona which occurs between porcelain insulators and support clamps of overhead lines used in 154[kV] power receiving facilities for end users were investigated. The corona, which cannot be identified by one common method, was measured utilizing a UV image camera. A risk assessment for fire damage and its status was suggested. The stress distribution of the electrical field by length of bare wire was suggested by means of the finite element method (FEMLAB). As a result, it was found to affect a porcelain insulators. These results can be utilized for the enhancement of clamp installation and safety in power facilities.