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Oxidative stress attenuates Fas-mediated apoptosis in Jurkat T cell line through Bfl-1 induction
Kim, Heejung,Kim, Yong-Nyun,Kim, Hyungsoo,Kim, Chul-Woo Nature Publishing Group 2005 Oncogene Vol.24 No.7
Many types of mammalian cells produce ROS in response to many different stimuli to modulate a number of cellular functions, including apoptosis. However, the correlation between ROS and apoptosis remains controversial, and the mechanisms whereby ROS-induced signals are propagated to critical downstream targets remain largely undefined. Here, we demonstrate that hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) upregulates the expression of Bfl-1, an antiapoptotic member of the Bcl-2 family, and that this is responsible for the antiapoptotic activity of ROS. When Jurkat, human leukemic T cells, were pretreated with 100 μM H<SUB>2</SUB>O<SUB>2</SUB> and then treated with anti-Fas antibody, apoptosis was impaired without change of cell surface Fas expression. An investigation of the expression patterns of Bcl-2 family genes revealed that H<SUB>2</SUB>O<SUB>2</SUB> treatment induced Bfl-1 gene expression, but left other genes unchanged, and this Bfl-1 expression and H<SUB>2</SUB>O<SUB>2</SUB>-induced antiapoptotic effect was inhibited by antioxidants or NF-κB inhibitor. In addition, an electromobility shift assay revealed that the p65/p50 subunits of NF-κB activated by H<SUB>2</SUB>O<SUB>2</SUB> bound to a bfl-1 promoter. Neither the induction of Bfl-1 nor the antiapoptotic effect of H<SUB>2</SUB>O<SUB>2</SUB> was detected in Bfl-1-knockdown Jurkat cell line containing Bfl-1 antisense (Bfl-1AS). These data indicate that oxidative stress induces the expression of Bfl-1 via NF-κB activation, and this early-response gene protects cells from Fas-mediated apoptosis. This may be a cellular survival mechanism of cells exposed to phagocytes-derived ROS.Oncogene (2005) 24, 1252–1261. doi:10.1038/sj.onc.1208282 Published online 13 December 2004
Lee, Hyungsoo,Jo, Min Chul,Sohn, Seok Su,Kim, Sang-Heon,Song, Taejin,Kim, Sung-Kyu,Kim, Hyoung Seop,Kim, Nack J.,Lee, Sunghak Elsevier 2019 Materials characterization Vol.147 No.-
<P><B>Abstract</B></P> <P>The weldability is one of the key factors governing applications of TWinning-Induced Plasticity (TWIP) steels to automotive industries demanding high economy, environmental friendliness, and high performance. During spot welding of Zn-coated Al-containing TWIP steel sheets, liquid metal embrittlement (LME) frequently occurs by Zn infiltration into grain boundaries to form cracks, but the direct observation and detailed analysis of LME cracking are quite difficult because it occurs instantaneously within a second. Here in the present study, the LME was investigated by detailed microstructural evolutions of small Zn infiltrations or cracks as well as formation behavior of various intermetallic phases. In the heat-affected zone, the applied tensile stress and spot-welding heat tore down a diffusion-inhibiting Fe<SUB>2</SUB>Al<SUB>5</SUB> layer formed between the Zn-coated layer and the TWIP steel substrate, and formed Zn-containing ferrite (α-Fe(Zn)) particles on the steel surface which provided paths for liquid Zn infiltration. α-Fe(Zn) particles played critical roles in accelerating the LME by reducing the ductility because they were brittle due to high contents of Zn and Al. In the present Al-containing TWIP steels, the increase in welding current generally aggravates the LME.</P>
Application study of red tide monitoring to desalination plants using chollian (COMS)
Kim, Taewoo,Kim, Jihoon,Yun, Hongsik,Kim, Hyungsoo Taylor Francis 2016 Desalination and Water Treatment Vol.57 No.55
<P>Chollian (Communication, Ocean, and Meteorological Satellite (COMS)) is a geostationary satellite developed jointly by the Ministry of Land, Infrastructure, and Transport (MOLIT), the Ministry of Education (MOE), the Korea Communications Commission (KCC), and the Korea Meteorological Administration (KMA). Chollian serves not only as communications and weather satellites but also as a marine observation satellite capable of detecting ocean surface 8 times a day with Geostationary Ocean Color Imager (GOCI). Most of the recent desalination plants use Seawater Reverse Osmosis (SWRO) process, and chlorine cannot be used because the RO membrane in the main SWRO process is made of polyamide (PA). Therefore, it is very vulnerable to biofouling due to the influence of red algae and marine micro-organisms contained in seawater. This study aimed to evaluate the applicability of the red tide monitoring system capable of detecting and preventing the influx of red algae adversely affecting operation and maintenance (O & M) of desalination plants using Chollian in advance. The analysis was performed on Gwangyang Bay in the South Sea, South Korea with desalination plants. According to the results, the chlorophyll-a concentration in the observed values of the Ocean Color Imager was highly correlated with Cochlodinium polykrikoides concentration of the experimental values in the analysis of water sampled from a boat at approximately 95% reliability (R-2).</P>
Hyungsoo Lee,Gyeong Su Kim,전창우,Seok Su Sohn,Sang-Bok Lee,Sang-Kwan Lee,Hyoung Seop Kim,이상관 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.4
Zr-based amorphous alloy matrix composites reinforced with tungsten (W) or tantalum (Ta) continuous fibers were fabricated by liquid pressing process. Their dynamic tensile properties were investigated in relation with microstructures and deformation mechanisms by using a split Hopkinson tension bar. The dynamic tensile test results indicated that the maximum strength of the W-fiber-reinforced composite (757 MPa) was much lower than the quasi-statically measured strength, whereas the Ta-fiber-reinforced composite showed very high maximum strength (2129 MPa). In the W-fiber-reinforced composite, the fracture abruptly occurred in perpendicular to the tensile direction because W fibers did not play a role in blocking cracks propagated from the amorphous matrix, thereby resulting in abrupt fracture within elastic range and consequent low tensile strength. The very high dynamic tensile strength of the Ta-fiber-reinforced composite could be explained by the presence of ductile Ta fibers in terms of mechanisms such as (1) interrupted propagation of cracks initiated in the amorphous matrix, (2) formation of lots of cracks in the amorphous matrix, and (3) sharing of loads and severe deformation (necking) of Ta fibers in cracked regions.
Kim, Hyungsoo,Rajamanickam, Ramachandran,Park, Ji-Woong Elsevier 2017 INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Vol.59 No.-
<P><B>Abstract</B></P> <P>A mixture of equivalent amounts of amidine, alcohol, and carbon dioxide forms alklycarbonate amidinium salts. Here we studied the effect of the composition of solutions consisting of ethylene glycol (EG) as the alcohol and one of various amidines on their ability to absorb and desorb carbon dioxide. Compounds containing single or multiple formamidine groups were synthesized and dissolved in EG. The ability of these solutions to absorb carbon dioxide was studied for various ratios of EG to amidine and at various temperatures. An excess of at least ten equivalents of EG relative to the amidine was required for rapid and complete reaction of the base with carbon dioxide. Excess EG also reduced the viscosity of the solution, and in this way increased the absorption rate. However, the excess EG appeared to have stabilized the formed alkyl carbonate salts via hydrogen bonding, resulting in a relatively low degree of decarbonation of the solution at elevated temperatures. This effect would cause the working capacity to be decreased were this type of material be used for carbon dioxide capture applications. Our results suggest that, in general, the compositions of the alcoholic solutions of superbases need to be optimized to achieve high-efficiency absorption and desorption of carbon dioxide.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Superbases with multiple amidine functionalities are prepared. </LI> <LI> Non-aqueous solutions of the superbases in alcohol capture carbon dioxide. </LI> <LI> Hydroxy-to-amidine group ratios of the solutions affect the capture efficiency. </LI> <LI> Multiple functionality of the absorbents improves the gravimetric capture capacity. </LI> </UL> </P>