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Effect of Highly Pressurized Hydrogen Gas Charging on the Hydrogen Embrittlement of API X70 Steel
Dong-Su Bae,Chi-Eun Sung1,Hyun-Ju Bang,Sang-Pill Lee,Jin-Kyung Lee,In-Soo Son,조영래,Un-Bong Baek,Seung-HoonNahm 대한금속·재료학회 2014 METALS AND MATERIALS International Vol.20 No.4
During the use of API X70 steel as a pipeline structural material for the transportation of natural gas,hydrogen embrittlement can occur due to the hydrogen contained in natural gas. The aim of this study is toinvestigate the effects of the hydrogen content under high-pressure hydrogen gas conditions on the hydrogenembrittlement of air-cooled API X70 steel. The air-cooled API X70 steel was manufactured by hot rollingand was then air-cooled to room temperature. Tensile test specimens were held for 0 h, 1000 h, and 2000 hwithin a pressure vessel filled with 100% hydrogen gas at a gas pressure of 10 MPa, with the tensile teststhen performed at room temperature. The microstructure of the API X70 steel consists of coarse polygonalferrite, coarse pearlite, and fine acicular ferrite. The yield and tensile strength increased and elongationdecreased considerably after a holding time of 2000 h compared to those of 0 h and 1000 h within the pressurevessel. The morphology of the fracture surface changed from ductile to brittle upon hydrogen gas charging. Secondary cracks were observed in both of the hydrogen-gas-charged specimens. No external cracks wereformed on the surface of the tensile-tested specimen with a 0 h holding time; however, many external crackswere observed on the specimen surface subjected to hydrogen gas charging.
Sung-Man Cho,Zheng Gen Piao,Yoon Bae Kim,Joong-Soo Kim,Kyungpyo Park 대한생리학회-대한약리학회 2002 The Korean Journal of Physiology & Pharmacology Vol.6 No.6
<P> There are some evidences that K<SUP></SUP> efflux evoked by muscarinic stimulation is not mainly mediated by large conductance K<SUP></SUP> (BK) channels in salivary gland. In this experiment, we therefore characterised non BK channels in rat submandibular gland acinar cells and examined the possibility of agonist effect on this channel using a patch clamp technique. Two types of K<SUP></SUP> channels were observed in these cells. BK channels were observed in 3 cells from total 6 cells and its average conductance was 152⁑7 pS (n=3). The conductance of the another types of K<SUP></SUP> channel was estimated as 71⁑7 pS (n=6). On the basis of the conductance of this channel, we defined this channel as intermediate conductance K<SUP> </SUP>(IK) channels, which were observed from all 6 cells we studied. When we increased Ca<SUP>2</SUP> concentration of the bath solution in inside-out mode, the IK channel activity was greatly increased, suggesting this channel is Ca<SUP>2</SUP> sensitive. We next examined the effect of carbachol (CCh) and isoproterenol on the activity of the IK channels. 10<SUP>5 </SUP>M isoproterenol significantly increased the open probability (Po) from 0.08⁑0.02 to 0.21⁑0.03 (n=4, P<0.05). Application of 10<SUP>5 </SUP>M CCh also increased Po from 0.048⁑0.03 to 0.55⁑0.33 (n=5, P<0.05) at the maximum channel activity. The degree of BK channel activation induced by the same concentration of CCh was lower than that of IK channels; Po value was 0.011⁑0.003 and 0.027⁑0.005 in control and during CCh stimulation (n=3), respectively. The result suggests that IK channels exist in salivary acinar cells and its channel activity is regulated by muscaricinic and β- adrenergic agonist. We conclude that IK channels also play a putative role in secretion as well as the BK channels in rat submandibular gland acinar cells.
Sung-Ho Bae,Jaeil Kim,Munchurl Kim,Sukhee Cho,Jin Soo Choi IEEE 2013 IEEE transactions on broadcasting Vol.59 No.2
<P>In this paper, we present the experimental results with analysis for subjective quality assessment on 4K-ultra-high definition (UHD) video encoded by high efficiency video coding (HEVC) to investigate its feasibility for 4K-UHD TV broadcasting services. The subjective quality assessment on the HEVC-encoded (impaired) 4K-UHD video is conducted for the three target bitrates of 18, 23, and 36 Mb/s, the two color formats of YUV420 and YUV444, and the two viewing distances of 0.75 times the height of a display screen (H) and 1.5 H. The subjective quality assessment experiments on 4K-UHD test sequences show that the HEVC-encoded (impaired) YUV420 4K-UHD video even at the target bit of 18 Mb/s yields perceptual similar visual quality: 1) with MOS of 4.7 and 4.8 in 0.75 H and 1.5 H viewing distances, respectively, compared to the original YUV420 4K-UHD test video; and 2) with MOS of 4.8 in 1.5 H viewing distance, compared to the original YUV444 4K-UHD test video. This implies that the HEVC-encoded YUV420 4K-UHD video at the target bit rate of 18 Mb/s is perceptually good enough in the usage of legacy DTV broadcasting systems with single channel bandwidths of 6 MHz. It is also shown that the HEVC-encoded 4K-UHD test sequences mostly yield higher perceptual quality in the 420 YUV color format than in the YUV444 color format at the same target bitrates.</P>
Bae, Sung-Ho,Seo, Yeon-Soo 생화학분자생물학회 2000 Journal of biochemistry and molecular biology Vol.33 No.2
The saccharomyces cerevisiae Rad27, a structure-specific endonuclease for the okazaski fragment maturation has been known to interact genetically and biochemically with Dna2, an essential enzyme for DNA replication. In an attempt to define the significance of the interaction between the two enzymes, we expressed and purified both Dna2 and Rad27 proteins. In this report, Rad27 could not form a complex with Dna2 in the three different analyses. The analyses included glycerol gradient sedimentation, protein-column chromatography, and coinfection of baculoviruses followed by affinity purification. This is in striking contrast to the previous results that used crude extracts. These results suggest that the interaction between the two proteins is not sufficiently stable or indirect, and thus requires an additional protein(s) in order for Rad27 and Dna2 to form a stable physical complex. This result is consistent with our genetic findings that Schizosaccharomyces pombe Dna2 is capable of interacting with several proteins that include two subunits of polymerase $\delta$, DNA ligase I, as well as Fen-1. In addition, we found that the N-terminal modification of Rad27 abolished its enzymatic activity. Thus, as suspected, we found that on the basis of the structure determination, N-terminal methionine indeed plays an important role in the nucleolytic cleavage reaction.
An unusual presentation of an inflammatory fibroid polyp of the ileum: A case report
BAE, JUN SANG,SONG, JI SOO,HONG, SEUNG-MO,MOON, WOO SUNG D.A. Spandidos 2015 Oncology letters Vol.9 No.1
<P>Inflammatory fibroid polyps (IFP) are rare, benign lesions of the gastrointestinal tract. Recent molecular studies of IFPs identified platelet-derived growth factor receptor α (PDGFRA)-activating mutations, suggesting possible neoplastic qualities to IFPs. IFPs originate from the submucosa and often extend into the overlying mucosa. Although certain IFPs infiltrate the muscularis propria focally, disruption of the muscularis propria and penetration into the subserosa is extremely rare. The current study presents an unusual case of an ileal IFP. A 48-year-old female visited the Department of Surgery, Chonbuk National University Hospital (Jeonju, Republic of Korea) due to abdominal pain. Radiological study demonstrated an ileocecal-type intussusception due to a luminal polypoid mass of the ileum. The excised tumor consisted of haphazardly arranged epithelioid and spindled cells in a fibromyxoid stroma, with an abundant vascular network, accompanied by an inflammatory reaction predominantly composed of eosinophilic infiltrates. The infiltrating tumor cells disrupted the muscularis mucosa above the tumor cells and the muscularis propria below the tumor cells, and extended into the subserosa. Immunohistochemically, the tumor cells were positive for vimentin and cluster of differentiation 34, while they were negative for keratin, PDGFRA, smooth muscle actin, desmin, S-100 protein, DOG-1 and c-kit. Sequencing analysis of c-kit exons 9, 11, 13 and 17, and PDGFRA exons 12 and 18 indicated a wild-type status. The patient has remained well for 12 months after surgery without further treatment, with no recurrence of the tumor. Although spread of IFP under the muscularis propria is rare, identification of similar cases and further study will enhance our understanding of the nature of this tumor.</P>
Sung Ho Lee,Tae-Hoon Kim,Yong-Seog Oh,Seil Oh,Jong-Il Choi,Jin-Bae Kim,Jong-Chun Nah,Sung Il Im,Ki-Woon Kang,Seongwook Han,June Soo Kim 대한의학회 2020 Journal of Korean medical science Vol.35 No.2
Background: An implantable loop recorder (ILR) is an effective tool for diagnosing unexplained syncope (US). We examined the diagnostic utility of an ILR in detecting arrhythmic causes of US and determining which clinical factors are associated with pacemaker (PM) implantation. Methods: This retrospective, multicenter, observational study was conducted from February 2006 to April 2018 at 11 hospitals in Korea. Eligible patients with recurrent US received an ILR to diagnose recurrent syncope and document arrhythmia. Results: A total of 173 US patients (mean age, 67.6 ± 16.5 years; 107 men [61.8%]) who received an ILR after a negative conventional workup were enrolled. During a mean follow-up of 9.4 ± 11.1 months, 52 patients (30.1%) had recurrent syncope, and syncope- correlated arrhythmia was confirmed in 34 patients (19.7%). The ILR analysis showed sinus node dysfunction in 24 patients (70.6%), supraventricular tachyarrhythmia in 4 (11.8%), ventricular arrhythmia in 4 (11.8%), and sudden atrioventricular block in 2 (5.9%). Overall, ILR detected significant arrhythmia in 99 patients (57.2%) irrespective of syncope. Among patients with clinically relevant arrhythmia detected by ILR, PM implantation was performed in 60 (34.7%), an intra-cardiac defibrillator in 5 (2.9%), and catheter ablation in 4 (2.3%). In a Cox regression analysis, history of paroxysmal atrial fibrillation (PAF) (hazard ratio [HR], 2.34; 95% confidence interval [CI], 1.33–4.12; P < 0.01) and any bundle branch block (BBB) (HR, 2.52; 95% CI, 1.09–5.85; P = 0.03) were significantly associated with PM implantation. Conclusion: ILR is useful for detecting syncope-correlated arrhythmia in patients with US. The risk of PM is high in US patients with a history of PAF and any BBB.