Fatigue performance of deepwater SCR under short-term VIV considering various S-N curves

Kim, D.K.,Choi, H.S.,Shin, C.S.,Liew, M.S.,Yu, S.Y.,Park, K.S. Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.5

In this study, a method for fatigue performance estimation of deepwater steel catenary riser (SCR) under short-term vortex-induced vibration was investigated for selected S-N curves. General tendency between S-N curve capacity and fatigue performance was analysed. SCRs are generally used to transport produced oil and gas or to export separated oil and gas, and are exposed to various environmental loads in terms of current, wave, wind and others. Current is closely related with VIV and it affects fatigue life of riser structures significantly. In this regards, the process of appropriate S-N curve selection was performed in the initial design stage based on the scale of fabrication-related initial imperfections such as welding, hot spot, crack, stress concentration factor, and others. To draw the general tendency, the effects of stress concentration factor (SCF), S-N curve type, current profile, and three different sizes of SCRs were considered, and the relationship between S-N curve capacity and short-term VIV fatigue performance of SCR was derived. In case of S-N curve selection, DNV (2012) guideline was adopted and four different current profiles of the Gulf of Mexico (normal condition and Hurricane condition) and Brazil (Amazon basin and Campos basin) were considered. The obtained results will be useful to select the S-N curve for deepwater SCRs and also to understand the relationship between S-N curve capacity and short-term VIV fatigue performance of deepwater SCRs.

Salmonella Typhi, Salmonella Enteritidis 및 Salmonella Typhimurium균에 대한 Phage typing 및 antibiogram 분석

신영학,유정식,오경수,이점규,이상원,고운영,양병국 국립보건연구원 2000 국립보건원보 Vol.37 No.-

Salmonella Typhi, Salmonella Typhimurium 및 Salmonella Enteritidis의 항균제 감수성 (1997)

신영학,유정식,김기상,정동준,오경수,이점규,이상원,이근영,박미선,이복권,김호훈 국립보건연구원 1998 국립보건원보 Vol.35 No.-

Antibiotic susceptibility and resistance of Streptococcus iniae and Streptococcus parauberis isolated from olive flounder (Paralichthys olivaceus)

Park, Y.K.,Nho, S.W.,Shin, G.W.,Park, S.B.,Jang, H.B.,Cha, I.S.,Ha, M.A.,Kim, Y.R.,Dalvi, R.S.,Kang, B.J.,Jung, T.S. Elsevier Scientific Pub. Co 2009 Veterinary microbiology Vol.136 No.1

The rates of antibiotic susceptibility and resistance were investigated in Streptococcus iniae and Streptococcus parauberis isolates obtained from diseased olive flounders (Paralichthys olivaceus) collected from fish farms in Jeju Island, Korea. Isolates of S. iniae (n=65) were susceptible to cefotaxime, erythromycin, ofloxacin, penicillin, tetracycline and vancomycin, as demonstrated by the minimum inhibitory concentration (MIC) test. Isolates of S. parauberis (n=86) were highly resistant to erythromycin (58% of the 86 isolates tested) and tetracycline (63% of the 86 isolates tested). Fifty-four isolates of tetracycline-resistant S. parauberis contained the tet(M/O/S) genes, of which 39 and 12 isolates contained the tet(M) and tet(S) genes, respectively, whereas 3 isolates contained both the tet(M) and tet(S) genes. Among the erythromycin-resistant isolates of S. parauberis (n=50) only 14 contained the erm(B) gene. These results suggest that the tet(S) and erm(B) genes of S. parauberis are involved in the acquisition of high-level resistance to erythromycin and tetracycline. Our findings reveal a high rate of antibiotic resistance among strains of S. parauberis and emphasize the need to develop an appropriate vaccine to reduce the use of antibiotics.

Sphingosine-1-phosphate-induced Flk-1 transactivation stimulates mouse embryonic stem cell proliferation through S1P₁/S1P₃-dependent β-arrestin/c-Src pathways

Ryu, J.M.,Baek, Y.B.,Shin, M.S.,Park, J.H.,Park, S.H.,Lee, J.H.,Han, H.J. Elsevier 2014 Stem cell research Vol.12 No.1

Although recent findings showed that the bioactive lipid metabolites can regulate the ES cell functions, the physiological relevance of interaction between sphingosine-1-phosphate (S1P) and Flk-1 and its related signaling molecules are not yet clear in ES cell proliferation. In the present study, S1P<SUB>1-5</SUB> receptors were expressed in mouse ES cells and S1P increased S1P<SUB>1-3</SUB> receptor expression level. S1P treatment stimulated the cellular proliferation in S1P<SUB>1/3</SUB>-dependent manner, located in lipid rafts. In response to S1P, β-arrestin was recruited to S1P<SUB>1/3</SUB> receptor and c-Src was activated. S1P also increased the binding of S1P<SUB>1/3</SUB> receptor with Flk-1. Similar to responses for VEGF, S1P increased Flk-1 phosphorylation, which was blocked by β-arrestin siRNA, and PP2, but not by VEGF-A<SUB>164</SUB> antibody or VEGF siRNA. In addition, S1P induced VEGF expression and VEGFR2 kinase inhibitor (SU1498) blocked the S1P-induced cellular proliferation. However, VEGF-A<SUB>164</SUB> antibody or VEGF siRNA partially blocked S1P-induced cellular proliferation, suggesting that both VEGF-dependent Flk-1 activation and VEGF-independent Flk-1 activation are involved in S1P-induced ES cell proliferation. S1P and VEGF-induced phosphorylation of ERK and JNK were blocked by pretreatment with SU1498. Moreover, inhibition of ERK and JNK blocked S1P-induced cellular proliferation. In conclusion, S1P-elicited transactivation of Flk-1 mediated by S1P<SUB>1/3</SUB>-dependent β-arrestin/c-Src pathways stimulated mouse ES cell proliferation.

Syntheses, crystal structures, circular dichroism, and magnetic properties of chiral dinuclear and polymeric nickel(II) compounds

Shin, J.W.,Son, H.J.,Kim, S.K.,Min, K.S. Pergamon Press 2013 Polyhedron Vol.52 No.-

Chiral dinuclear nickel(II) complexes, [Ni(L<SUP>R,R</SUP>)(C<SUB>2</SUB>O<SUB>4</SUB>)Ni(L<SUP>R,R</SUP>)](ClO<SUB>4</SUB>)<SUB>2</SUB>.4CH<SUB>3</SUB>CN (3) and [Ni(L<SUP>S,S</SUP>)(C<SUB>2</SUB>O<SUB>4</SUB>)Ni(L<SUP>S,S</SUP>)](ClO<SUB>4</SUB>)<SUB>2</SUB>.4CH<SUB>3</SUB>CN (4) and chiral polymeric compounds, [Ni(L<SUP>R,R</SUP>)(CrO<SUB>4</SUB>)]<SUB>n</SUB>.2H<SUB>2</SUB>O.CH<SUB>3</SUB>CN (5) and [Ni(L<SUP>S,S</SUP>)(CrO<SUB>4</SUB>)]<SUB>n</SUB>.2H<SUB>2</SUB>O.CH<SUB>3</SUB>CN (6) have been synthesized and characterized (L<SUP>R,R/S,S</SUP>=1,8-di((R/S)-α-methylbenzyl)-1,3,6,8,10,13-hexaazacyclotetradecane). These chiral compounds were characterized by X-ray crystallography, circular dichroism, and molecular magnetism. The nickel(II) ions in 3 and 4 have a distorted octahedral geometry by coordination with four nitrogens of a macrocyclic ligand with chiral pendents in a folded conformation and two oxygens of an oxalate ion in the cis positions. The nickel(II) ions in 5 and 6 have a distorted octahedral geometry by coordination with four nitrogens of a macrocyclic ligand in a planar conformation and two oxygens of two chromate ions in the axial positions. Complexes 3 and 4 show strong antiferromagnetic interactions [3: g=2.36, J/k<SUB>B</SUB>=-29.9K (-20.8cm<SUP>-1</SUP>); 4: g=2.18, J/k<SUB>B</SUB>=-25.5K (-17.7cm<SUP>-1</SUP>)], while 5 and 6 exhibit weak antiferromagnetic couplings [5: g=2.25, J/k<SUB>B</SUB>=-1.20K (-0.83cm<SUP>-1</SUP>); 6: g=2.25, J/k<SUB>B</SUB>=-0.68K (-0.47cm<SUP>-1</SUP>)]. The former complexes occur strong antiferromagnetic interactions via the oxalato bridges within the nickel(II) dimers, the latter compounds are weak antiferromagnetic interactions through the chromate ions within the 1D polymers. The circular dichroism (CD) spectrum of 3 has exhibited two negative peaks at 336 and 533nm, and that of 4 has displayed an enantiomeric pattern. The CD spectrum of 5 has appeared a negative absorption above ca. 550nm, while that of 6 has shown an enantiomeric pattern in the same wavelength region.

The microRNA miR-124 inhibits vascular smooth muscle cell proliferation by targeting S100 calcium-binding protein A4 (S100A4)

Choe, N.,Kwon, D. H.,Shin, S.,Kim, Y. S.,Kim, Y. K.,Kim, J.,Ahn, Y.,Eom, G. H.,Kook, H. Elsevier Science B.V., Amsterdam. 2017 FEBS letters Vol.591 No.7

<P>S100 calcium-binding protein A4 (S100A4) induces proliferation and migration of vascular smooth muscle cells (VSMCs). We aimed to find the microRNA regulating S100A4 expression. S100A4 transcripts are abruptly increased in the acute phase of carotid arterial injury 1 day later (at day 1) but gradually decreases at days 7 and 14. Bioinformatics analysis reveals that miR-124 targets S100A4. VSMC survival is attenuated by miR-124 mimic but increased by miR-124 inhibitor. miR-124 decreases immediately after carotid arterial injury but dramatically increases at days 7 and 14. miR-124 inhibitor-induced cell proliferation is blocked by S100A4 siRNA, whereas miR-124-induced cell death is recovered by S100A4. Our findings suggest that miR-124 is a novel regulator of VSMC proliferation and may play a role in the development of neointimal proliferation.</P>

Fatigue performance of deepwater SCR under short-term VIV considering various S-N curves

D.K. Kim,최한석,C.S. Shin,M.S. Liew,유수영,K.S. Park 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.5

In this study, a method for fatigue performance estimation of deepwater steel catenary riser (SCR) under short-term vortex-induced vibration was investigated for selected S-N curves. General tendency between S-N curve capacity and fatigue performance was analysed. SCRs are generally used to transport produced oil and gas or to export separated oil and gas, and are exposed to various environmental loads in terms of current, wave, wind and others. Current is closely related with VIV and it affects fatiguelife of riser structures significantly. In this regards, the process of appropriate S-N curve selection was performed in the initial design stage based on the scale of fabrication-related initial imperfections such as welding, hot spot, crack, stress concentration factor, and others. To draw the general tendency, the effects of stress concentration factor (SCF), S-N curve type, current profile, and three different sizes of SCRs wereconsidered, and the relationship between S-N curve capacity and short-term VIV fatigue performance of SCR was derived. In case of S-N curve selection, DNV (2012) guideline was adopted and four different current profiles of the Gulf of Mexico (normal condition and Hurricane condition) and Brazil (Amazon basin and Campos basin) were considered. The obtained results will be useful to select the S-N curve for deepwater SCRs and also to understand the relationship between S-N curve capacity and short-term VIV fatigue performance of deepwater SCRs.

S-BRT 운행행태를 고려한 저상버스의 정차시간 예측모형

신소명,이수범,김영찬,박신형,유연승,최정훈,Shin, S.M.,Lee, S.B.,Kim, Y.C.,Park, S.H.,Yu, Y.S.,Choi, J.H. 한국안전학회 2021 한국안전학회지 Vol.36 No.1

This basic study introduces the concept of S-BRT and develops dwell time estimation models that consider road geometry and S-BRT characteristics for a signal operation strategy to meet the S-BRT's operational goal of high speed and punctuality. Field surveys of low-floor buses similar in shape to S-BRTs and data collection of passengers, station elements, vehicle elements, and other factors that can affect stop times were used in a regression analysis to establish statistically significant dwell time estimation models. These dwell time estimation models are developed by categorizing according to the locations of the signal or sidewalk that have the most impact on the dwell time. In this way, the number of people boarding and alighting the bus at the crowded door and the number of people boarding and alighting the bus at the front door considering the internal congestion was analyzed to affect the dwell time. The estimation dwell time models in this study can be used in the establishment of strategies that provide priority signals to S-BRTs.

상업적 응유효소의 탈지유에 대한 단백질 분해 작용

신현수,김상범,임종우 한국동물자원과학회 2002 한국축산학회지 Vol.44 No.6

상업적 단백질 분해 효소에 0.02% CaCl_2를 첨가하여 응유 활성화를 시킨 탈지유에 대한 분해 작용의 결과를 요약하면 다음과 같다. 다양한 효소별 가수분해 시간에 따른 가수분해도는 미생물 유래 효소와 trypsin은 pepsin과 papain W-40보다 높은 분해도를 나타냈다. 12% TCA 용액에 가용성인 NPN의 양은 trypsin이 가장 높은 분해도를 나타내었고 rennet과 pepsin이 가장 낮은 분해도를 보였다. 전기영동에 있어서 trypsin과 protease S는 α-lactalbumin을 분해하였고 papain w-40은 β-lactoglobulin을 미약하게 분해하였으며 neutrase 1.5는 90분 이후부터 α-lactalbumin과 β-lactoglobulin을 분해하였다. Rennet과 비교한 전기영동상에서는 rennet에 의해 분해 되지 않은 α_s-casein과 β-casein을 trypsin과 protease S가 다량 분해하였고 k-casein은 rennet에 비해 papain W-40이 상당 수준의 분해상을 나타내었다. 이상의 결과 가수분해도 및 NPN 양은 trypsin, neutrase 1.5 및 protease S가 다른 효소에 비해 높게 나타났으며, 전기영동상에서는 pepsin과 neutrase 1.5가 rennet과 유사한 경향을 나타내었다. Proteolytic activities of some commercial milk clotting enzymes(rennet, trypsin, pepsin, papain W-40, neutrase 1.5 and protease S) in bovine skim milk containing 0.02% CaCl_2 were determined by measuring DH(Degree of Hydrolysis), NPN(Non Protein Nitrogen) and by comparing patterns of SDS-PAGE(Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis). The DH of microbial enzymes(neutrase 1.5 and protease S) and trypsin in bovine skim milk were higher than those of pepsin and papain W-40. The amounts of NPN in the milk treated with trypsin and the other animal enzymes(rennet and pepsin) showed the highest and lowest degrees of proteolysis, respectively. SDS-PAGE showed that trypsin and protease S hydrolyzed α-lactalbumin and papain W-40 hydrolyzed β-lactoglobulin slightly, while neutrase 1.5 hydrolyzed both α-lactalbumin and β-lactoglobulin after treating for 90 min. Trypsin and protease S easily hydrolyzed α_s-casein and β-casein, which were not hydrolyzed by rennet. Papain W-40 hydrolyzed k-casein more than rennet as shown in SDS-PAGE. Based on the results of the experiments, the DH and NPN of trypsin, neutrase 1.5 and protease S were shown to be higher than those of the other enzymes. The SDS-PAGE patterns of papain W-40 and neutrase 1.5 were similar with that of rennet.