수정된 equivalent capcity를 이용한 VBR MPEG 비디오 트랙픽의 등가대역폭 계산방법

하경봉,이창범,박래홍 대한전자공학회 1996 전자공학회논문지-A Vol.33 No.10

A method for computing effectiv ebandwidth of aggregated varable bit rate (VBR) moving picture experts group (MPEG) video traffic is proposed. To compute statistical characteristics of aggregated MPEG traffic, first we split input MPEG traffic into I, B, and P frame traffics and aggregate respective I, B, and P frame traffics according to the frame type. Second statisticsal characteristics of the aggregated MPEG traffic are obtained using those of aggregated I, B, and P frame traffics. The effective bandwidth of the aggregated I frame traffic is computed by using the gaussian bound. Using the modified equivalent capacity, we obtain the effective bandwidths of aggregated B and P frame traffics and then compute the effective bandwidth of the combined B and P frame traffic. Finally the effective bandwidth of the aggregated MPEG traffic is computed by adding the gaussian bound of the aggregated I frame traffic and modifed equivalent capacity of combined B and P frame traffic. Computer simulation shows that the proposed method estimates effective bandwidth of the aggregated MPEG traffic well.

EW-7197 Attenuates the Progression of Diabetic Nephropathy in db/db Mice through Suppression of Fibrogenesis and Inflammation

하경봉,Weerapon Sangartit,정아름,이은수,김홍민,심소연,Upa Kukongviriyapan,Dae-Kee Kim,이은영,정춘희 대한내분비학회 2022 Endocrinology and metabolism Vol.37 No.1

Background: Diabetic nephropathy (DN) is characterized by albuminuria and accumulation of extracellular matrix (ECM) in kidney. Transforming growth factor-β (TGF-β) plays a central role in promoting ECM accumulation. We aimed to examine the effects of EW-7197, an inhibitor of TGF-β type 1 receptor kinase (ALK5), in retarding the progression of DN, both in vivo, using a diabetic mouse model (db/db mice), and in vitro, in podocytes and mesangial cells. Methods: In vivo study: 8-week-old db/db mice were orally administered EW-7197 at a dose of 5 or 20 mg/kg/day for 10 weeks. Metabolic parameters and renal function were monitored. Glomerular histomorphology and renal protein expression were evaluated by histochemical staining and Western blot analyses, respectively. In vitro study: DN was induced by high glucose (30 mM) in podocytes and TGF-β (2 ng/mL) in mesangial cells. Cells were treated with EW-7197 (500 nM) for 24 hours and the mechanism associated with the attenuation of DN was investigated. Results: Enhanced albuminuria and glomerular morphohistological changes were observed in db/db compared to that of the nondiabetic (db/m) mice. These alterations were associated with the activation of the TGF-β signaling pathway. Treatment with EW-7197 significantly inhibited TGF-β signaling, inflammation, apoptosis, reactive oxygen species, and endoplasmic reticulum stress in diabetic mice and renal cells. Conclusion: EW-7197 exhibits renoprotective effect in DN. EW-7197 alleviates renal fibrosis and inflammation in diabetes by inhibiting downstream TGF-β signaling, thereby retarding the progression of DN. Our study supports EW-7197 as a therapeutically beneficial compound to treat DN.

Tetrahydrocurcumin Ameliorates Kidney Injury and High Systolic Blood Pressure in High-Fat Diet-Induced Type 2 Diabetic Mice

Weerapon Sangartit,하경봉,이은수,김홍민,Upa Kukongviriyapan,이은영,정춘희 대한내분비학회 2021 Endocrinology and metabolism Vol.36 No.4

Background: Activation of the intrarenal renin-angiotensin system (RAS) is implicated in the pathogenesis of kidney injury and hypertension. We aimed to investigate the protective effect of tetrahydrocurcumin (THU) on intrarenal RAS expression, kidney injury,and systolic blood pressure (SBP) in high-fat diet (HFD)-induced type 2 diabetic mice. Methods: Eight-week-old male mice were fed a regular diet (RD) or HFD for 12 weeks, and THU (50 or 100 mg/kg/day) was intragastrically administered with HFD. Physiological and metabolic changes were monitored and the expression of RAS componentsand markers of kidney injury were assessed. Results: HFD-fed mice exhibited hyperglycemia, insulin resistance, and dyslipidemia compared to those in the RD group (P<0.05). Kidney injury in these mice was indicated by an increase in the ratio of albumin to creatinine, glomerular hypertrophy, and the effacement of podocyte foot processes. Expression of intrarenal angiotensin-converting enzyme, angiotensin II type I receptor, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-4, and monocyte chemoattractant protein-1 was also markedly increasedin HFD-fed mice. HFD-fed mice exhibited elevated SBP that was accompanied by an increase in the wall thickness and vascularcross-sectional area (P<0.05), 12 weeks post-HFD consumption. Treatment with THU (100 mg/kg/day) suppressed intrarenal RASactivation, improved insulin sensitivity, and reduced SBP, thus, attenuating kidney injury in these mice. Conclusion: THU alleviated kidney injury in mice with HFD-induced type 2 diabetes, possibly by blunting the activation of the intrarenal RAS/nicotinamide adenine dinucleotide phosphate oxidase IV (NOX4)/monocyte chemoattractant protein 1 (MCP-1) axisand by lowering the high SBP.

DWN12088, A Prolyl-tRNA Synthetase Inhibitor, Alleviates Hepatic Injury in Nonalcoholic Steatohepatitis

이동건,조수호,이은수,하경봉,박나원,공덕훈,박상인,박준석,Chung Choon Hee 대한당뇨병학회 2024 Diabetes and Metabolism Journal Vol.48 No.1

Background: Nonalcoholic steatohepatitis (NASH) is a liver disease caused by obesity that leads to hepatic lipoapoptosis, resulting in fibrosis and cirrhosis. However, the mechanism underlying NASH is largely unknown, and there is currently no effective therapeutic agent against it. DWN12088, an agent used for treating idiopathic pulmonary fibrosis, is a selective prolyl-tRNA synthetase (PRS) inhibitor that suppresses the synthesis of collagen. However, the mechanism underlying the hepatoprotective effect of DWN12088 is not clear. Therefore, we investigated the role of DWN12088 in NASH progression.Methods: Mice were fed a chow diet or methionine-choline deficient (MCD)-diet, which was administered with DWN12088 or saline by oral gavage for 6 weeks. The effects of DWN12088 on NASH were evaluated by pathophysiological examinations, such as real-time quantitative reverse transcription polymerase chain reaction, immunoblotting, biochemical analysis, and immunohistochemistry. Molecular and cellular mechanisms of hepatic injury were assessed by <i>in vitro</i> cell culture.Results: DWN12088 attenuated palmitic acid (PA)-induced lipid accumulation and lipoapoptosis by downregulating the Rho-kinase (ROCK)/AMP-activated protein kinase (AMPK)/sterol regulatory element-binding protein-1c (SREBP-1c) and protein kinase R-like endoplasmic reticulum kinase (PERK)/α subunit of eukaryotic initiation factor 2 (eIF2α)/activating transcription factor 4 (ATF4)/C/EBP-homologous protein (CHOP) signaling cascades. PA increased but DWN12088 inhibited the phosphorylation of nuclear factor-κB (NF-κB) p65 (Ser536, Ser276) and the expression of proinflammatory genes. Moreover, the DWN12088 inhibited transforming growth factor β (TGFβ)-induced pro-fibrotic gene expression by suppressing TGFβ receptor 1 (TGFβR1)/Smad2/3 and TGFβR1/glutamyl-prolyl-tRNA synthetase (EPRS)/signal transducer and activator of transcription 6 (STAT6) axis signaling. In the case of MCD-diet-induced NASH, DWN12088 reduced hepatic steatosis, inflammation, and lipoapoptosis and prevented the progression of fibrosis.Conclusion: Our findings provide new insights about DWN12088, namely that it plays an important role in the overall improvement of NASH. Hence, DWN12088 shows great potential to be developed as a new integrated therapeutic agent for NASH.

코로나19 관련 중국의 관광정책 동향

다이빈(戴斌),양진쏭(楊經松),쏭쯔첸(宋子千),허충펑(何瓊峰),짜오이징(趙一靜) 한국문화관광연구원 2020 한국관광정책 Vol.- No.80