Yeungnam University

About: Yeungnam University is a education organization based out in Daegu, South Korea. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 9885 authors who have published 22075 publications receiving 372798 citations.

Rheological, mechanical and biodegradation studies on blends of thermoplastic starch and polycaprolactone

Abstract: Polycaprolactone (PCL) has been blended with thermoplastic starch (TPS), prepared from regular corn starch and glycerol, in a twin-screw extruder. The rheological, mechanical, thermal and morphological properties of the blends were examined. Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) studies revealed that PCL/TPS blends are thermodynamically immiscible. However, they form compatible blends as a result of the hydrogen bonding interaction between the ester carbonyl of PCL and the OH groups on starch. Biodegradability of the blends increased with increasing TPS content. Dynamic viscoelastic measurements concluded that blends containing above 60-wt% TPS had higher storage and loss moduli than those of pure TPS and PCL. In addition, these blends had higher complex viscosities. Polym. Eng. Sci. 44:1429–1438, 2004. © 2004 Society of Plastics Engineers.

A mechanism for rivulet formation in heated falling films

Abstract: We consider a long-wave evolution equation that governs a draining film on a heated plate and hence is capable of describing both surface-wave and thermocapillary instabilities. When the flow and heat transfer rates are moderate, we show, via weakly nonlinear analysis of a truncated system and numerical simulation of the full nonlinear evolution equation, that coupled temporal instabilities can create surface deformations that lead to an array of rivulets aligned with the flow. This work thus demonstrates a mechanism of rivulet formation based solely on instability phenomena.

Adiponectin and Heme Oxygenase-1 Suppress TLR4/MyD88-Independent Signaling in Rat Kupffer Cells and in Mice after Chronic Ethanol Exposure

Abstract: Alcoholic liver disease is mediated via activation of TLR4 signaling; MyD88-dependent and -independent signals are important contributors to injury in mouse models. Adiponectin, an anti-inflammatory adipokine, suppresses TLR4/MyD88-dependent responses via induction of heme oxygenase-1 (HO-1). Here we investigated the interactions between chronic ethanol, adiponectin, and HO-1 in regulation of TLR4/MyD88-independent signaling in macrophages and an in vivo mouse model. After chronic ethanol feeding, LPS-stimulated expression of IFN-β and CXCL10 mRNA was increased in primary cultures of Kupffer cells compared with pair-fed control mice. Treatment of Kupffer cells with globular adiponectin (gAcrp) normalized this response. LPS-stimulated IFN-β/CXCL10 mRNA and CXCL10 protein was also reduced in RAW 264.7 macrophages treated with gAcrp or full-length adiponectin. gAcrp and full-length adiponectin acted via adiponectin receptors 1 and 2, respectively. gAcrp decreased TLR4 expression in both Kupffer cells and RAW 264.7 macrophages. Small interfering RNA knockdown of HO-1 or inhibition of HO-1 activity with zinc protoporphyrin blocked these effects of gAcrp. C57BL/6 mice were exposed to chronic ethanol feeding, with or without treatment with cobalt protoporphyrin, to induce HO-1. After chronic ethanol feeding, mice were sensitized to in vivo challenge with LPS, expressing increased IFN-β/CXCL10 mRNA and CXCL10 protein in liver compared with control mice. Pretreatment with cobalt protoporphyrin 24 h before LPS challenge normalized this effect of ethanol. Adiponectin and induction of HO-1 potently suppressed TLR4-dependent/MyD88-independent cytokine expression in primary Kupffer cells from rats and in mouse liver after chronic ethanol exposure. These data suggest that induction of HO-1 may be a useful therapeutic strategy in alcoholic liver disease.