Interference Effect betweenϕandΛ(1520)Production Channels in theγp→K+K−pReaction near Threshold

Ryu, S. Y.,Ahn, J. K.,Nakano, T.,Ahn, D. S.,Ajimura, S.,Akimune, H.,Asano, Y.,Chang, W. C.,Chen, J. Y.,Daté,, S.,Ejiri, H.,Fujimura, H.,Fujiwara, M.,Fukui, S.,Hasegawa, S.,Hicks, K.,Horie, K.,Ho American Physical Society 2016 Physical Review Letters Vol.116 No.23

<P>The phi-Lambda(1520) interference effect in the gamma p -> K(+)K(-)p reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between phi and Lambda(1520) production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when K+K- pairs are observed at forward angles but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the root s = 2.1 GeV bump structure in forward differential cross sections for phi photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange, or rescattering processes via other hyperon states.</P>

Phase II study of S-1 combined with oxaliplatin as therapy for patients with metastatic biliary tract cancer: influence of the <i>CYP2A6</i> polymorphism on pharmacokinetics and clinical activity

Kim, K-p,Jang, G,Hong, Y S,Lim, H-S,Bae, K-s,Kim, H-S,Lee, S S,Shin, J-G,Lee, J-L,Ryu, M-H,Chang, H-M,Kang, Y-K,Kim, T W Nature Publishing Group 2011 The British journal of cancer Vol.104 No.4

<P><B>Background:</B></P><P>Advanced biliary cancer is often treated with fluoropyrimidine-based chemotherapy. In this study, we evaluated the efficacy and tolerability of a combination of S-1, an oral fluoropyrimidine prodrug, and oxaliplatin in patients with metastatic biliary cancer.</P><P><B>Methods:</B></P><P>Patients with histologically confirmed metastatic biliary cancer and no history of radiotherapy or chemotherapy were enrolled. Oxaliplatin was administered intravenously (130 mg m<SUP>−2</SUP>), followed by 14-day administration of oral S-1 (40 mg m<SUP>−2</SUP> twice daily) with a subsequent 7-day rest period every 21 days. Pharmacokinetic analysis of S-1 was performed at cycle 1. Patients were genotyped for <I>CYP2A6</I> polymorphisms (<SUP>*</SUP>1, <SUP>*</SUP>4, <SUP>*</SUP>7, <SUP>*</SUP>9 or <SUP>*</SUP>10), and pharmacokinetic and clinical parameters compared according to the <I>CYP2A6</I> genotype.</P><P><B>Results:</B></P><P>In total, 49 patients were evaluated, who received a median of four cycles. The overall response rate was 24.5%. Median progression-free and overall survival was 3.7 and 8.7 months, respectively. The most common haematological grade 3 out of 4 toxicity was neutropenia (14%), while non-hematological grade 3 out of 4 toxicities included anorexia (14%), nausea (12%), asthenia (10%), vomiting (10%), and diarrhoea (4%). Biotransformation of S-1 (AUC<SUB>0−24 h</SUB> of 5-fluorouracil/AUC<SUB>0−24 h</SUB> of tegafur) was 1.85-fold higher for the <I>*1/*1</I> group than for the other groups (90% confidence interval 1.37–2.49). Diarrhoea (<I>P</I>=0.0740), neutropenia (<I>P</I>=0.396), and clinical efficacy (response rate, <I>P</I>=0.583; PFS, <I>P</I>=0.916) were not significantly associated with <I>CYP2A6</I> genotype, despite differences in 5-FU exposure.</P><P><B>Conclusion:</B></P><P>The combination of S-1 and oxaliplatin appears to be active and well tolerated in patients with metastatic biliary cancer, and thus is feasible as a therapeutic modality. <I>CYP2A6</I> genotypes are associated with differences in the biotransformation of S-1. However, the impact of the <I>CYP2A6</I> polymorphism on variations in clinical efficacy or toxicity requires further evaluation.</P>

Functionality improvement of fungal lignin peroxidase by DNA shuffling for 2,4-dichlorophenol degradability and H₂O₂ stability

Ryu, K.,Hwang, S.Y.,Kim, K.H.,Kang, J.H.,Lee, E.K. Elsevier Science Publishers 2008 Journal of biotechnology Vol.133 No.1

One of the major problems of wild-type lignin peroxidase (LiP) is its inactivity at the presence of excess H<SUB>2</SUB>O<SUB>2</SUB> and high concentration of aromatic compounds. Little is known about the substrate-binding site of LiP, and functionality improvement of LiP was not actively tried by genetic engineering and directed evolution. In order to improve LiPs functionality, we performed directed evolution with a colorimetric screening method. Finally, three types of LiP mutants were screened. The catalytic efficiency of the variants toward 2,4-dichlorophenol (DCP) degradation activity and the stability against H<SUB>2</SUB>O<SUB>2</SUB> was increased over the wild type. The K<SUB>m</SUB> value of the variants toward H<SUB>2</SUB>O<SUB>2</SUB> was increased, but K<SUB>m</SUB> value toward 2,4-DCP degradation was reduced. Overall, The K<SUB>cat</SUB>/K<SUB>m</SUB> values of the mutants toward 2,4-DCP was increased ca. 4-fold, and that toward H<SUB>2</SUB>O<SUB>2</SUB> was increased ca. 89-fold. Amino acid sequence analysis indicated that the most of the mutations were located on the enzyme surface. We expect that these results coupled with recombining mutation can be successfully applied to the molecular evolution cycles for screening of LiPs and other oxidative enzymes with improved functionality and stability.

High-Performance Blue InGaN Laser Diodes With Single-Quantum-Well Active Layers

Ryu, H.Y.,Haleem, K.H.,Lee, S.N.,Jang, T.,Son, J.K.,Paek, H.S.,Sung, Y.J.,Kim, H.K.,Kim, K.S.,O.H. Nam,Park, Y.J.,Shim, J.I. IEEE 2007 Photonics Technology Letters Vol.19 No.21

<P>The authors report on the high-performance blue laser diodes (LDs) with an emission wavelength of ~448 nm employing InGaN single-quantum-well (QW) active layers. At 100-mW continuous-wave (CW) output power, operation current and voltage are, respectively, 150 mA and 5.3 V, corresponding to the wall plug efficiency of >12%, a record value for the single-mode InGaN LDs with blue wavelengths. The single QW blue LD showed normal temperature dependence of light output-current curves with the characteristic temperature of 170 K. In addition, we demonstrate a high level of catastrophic optical damage of >300 mW and long device lifetime under CW operation condition at room temperature.</P>

Soft Magnetic Properties of Annealed Co - Based Amorphous Co66Fe₄Ni₁B15Si₁₄ Alloy Ribbon

J. S. Yang,D. Son,Y. Cho,K. S. Ryu 한국자기학회 1997 Journal of Magnetics Vol.2 No.4

The amorphous Co-based alloy Co_(66)Fe₄Ni₁B_(15)Si₁₄ (Metglas^® 2714A) is a suitable magnetic core material for high frequency operation. Appreciable reduction of the coercive force can be achieved by proper heat treatment. In this study, samples annealed at wide temperature range were analyzed using differential scanning calorimetry, high frequency B-H loop tester, X-ray diffractometer and resistivity meter. The results show that coercive force at 10 ㎑ decreases with increasing annealing temperature up to 773 K, but dramatically increases above this temperature. The squareness shows that the magnetic anisotropy on longitudinal direction of the as-cast state remains up to 773 K. Above this temperature, it decreases down to 0.5 that represents random distribution of magnetic domains. The crystallization abruptly occurs between 781 K and 783 K.

Combinatorial expression of bacterial whole mevalonate pathway for the production of β-carotene in E. coli

Yoon, S.H.,Lee, S.H.,Das, A.,Ryu, H.K.,Jang, H.J.,Kim, J.Y.,Oh, D.K.,Keasling, J.D.,Kim, S.W. Elsevier Science Publishers 2009 Journal of biotechnology Vol.140 No.3

The increased synthesis of building blocks of IPP (isopentenyl diphosphate) and DMAPP (dimethylallyl diphosphate) through metabolic engineering is a way to enhance the production of carotenoids. Using E. coli as a host, IPP and DMAPP supply can be increased significantly through the introduction of foreign MVA (mevalonate) pathway into it. The MVA pathway is split into two parts with the top and bottom portions supplying mevalonate from acetyl-CoA, and IPP and DMAPP from mevalonate, respectively. The bottom portions of MVA pathway from Streptococcus pneumonia, Enterococcus faecalis, Staphylococcus aureus, Streptococcus pyogenes and Saccharomyces cerevisiae were compared with exogenous mevalonate supplementation for β-carotene production in recombinant Escherichia coli harboring β-carotene synthesis genes. The E. coli harboring the bottom MVA pathway of S. pneumoniae produced the highest amount of β-carotene. The top portions of MVA pathway were also compared and the top MVA pathway of E. faecalis was found out to be the most efficient for mevalonate production in E. coli. The whole MVA pathway was constructed by combining the bottom and top portions of MVA pathway of S. pneumoniae and E. faecalis, respectively. The recombinant E. coli harboring the whole MVA pathway and β-carotene synthesis genes produced high amount of β-carotene even without exogenous mevalonate supplementation. When comparing various E. coli strains - MG1655, DH5α, S17-1, XL1-Blue and BL21 - the DH5α was found to be the best β-carotene producer. Using glycerol as the carbon source for β-carotene production was found to be superior to glucose, galactose, xylose and maltose. The recombinant E. coli DH5α harboring the whole MVA pathway and β-carotene synthesis genes produced β-carotene of 465mg/L at glycerol concentration of 2% (w/v).

<i>CYP2A6</i> and <i>ERCC1</i> polymorphisms correlate with efficacy of S-1 plus cisplatin in metastatic gastric cancer patients

Park, S R,Kong, S-Y,Nam, B-H,Choi, I J,Kim, C G,Lee, J Y,Cho, S J,Kim, Y W,Ryu, K W,Lee, J H,Rhee, J,Park, Y-I,Kim, N K Nature Publishing Group 2011 The British journal of cancer Vol.104 No.7

<P><B>Background:</B></P><P>We evaluated the association between polymorphisms of cytochrome P450 2A6 (<I>CYP2A6</I>)/excision repair cross-complementation group 1 (<I>ERCC1</I>)/X-ray repair cross-complementing group 1(<I>XRCC1</I>) and treatment outcomes of metastatic gastric cancer (MGC) patients treated with S-1/cisplatin.</P><P><B>Methods:</B></P><P>Among MGC patients (<I>n</I>=108), who received S-1 (40 mg m<SUP>−2</SUP> b.i.d., days 1–14) and cisplatin (60 mg m<SUP>−2</SUP>, day 1) every 3 weeks, we analysed the wild-type allele (<I>W</I>) and variants (<I>V</I>) of <I>CYP2A6</I> (<I>*4</I>, <I>*7, *9, *10</I>), and the polymorphisms of <I>ERCC1</I> (rs11615, rs3212986) and <I>XRCC1</I> (rs25487).</P><P><B>Results:</B></P><P>Patients having fewer <I>CYP2A6</I> variants had better response rates (<I>W</I>/<I>W vs W</I>/<I>V</I> other than <I>*1/*4 vs V</I>/<I>V</I> or <I>*1/*4</I>=66.7 <I>vs</I> 58.3 <I>vs</I> 32.3% <I>P</I>=0.008), time to progression (TTP) (7.2 <I>vs</I> 6.1 <I>vs</I> 3.5 months, <I>P</I>=0.021), and overall survival (23.2 <I>vs</I> 15.4 <I>vs</I> 12.0 months, <I>P</I>=0.004). <I>ERCC1 19442C</I>><I>A</I> (rs3212986) was also associated with response rate (<I>C/C</I>, 46.7% <I>vs C/A</I>, 55.3% <I>vs A/A</I>, 87.5%) (<I>P</I>=0.048) and TTP (4.4 <I>vs</I> 7.6 <I>vs</I> 7.9 months) (<I>P</I>=0.012). Patients carrying both risk genotypes of <I>CYP2A6</I> (<I>V</I>/<I>V</I> or <I>1/*4</I>) and <I>ERCC1 19442C</I>><I>A</I> (<I>C/C</I>) <I>vs</I> those carrying none showed an adjusted odds ratio of 0.113 (<I>P</I>=0.004) for response, and adjusted hazard ratios of 3.748 (<I>P</I>=0.0001) for TTP and 2.961 (<I>P</I>=0.006) for death.</P><P><B>Conclusion:</B></P><P>Polymorphisms of <I>CYP2A6</I> and <I>ERCC1 19442C</I>><I>A</I> correlated with the efficacy of S-1/cisplatin.</P>

Phase I/II study of S-1 combined with weekly docetaxel in patients with metastatic gastric carcinoma

Park, S R,Kim, H K,Kim, C G,Choi, I J,Lee, J S,Lee, J H,Ryu, K W,Kim, Y-W,Bae, J-M,Kim, N K Cancer Research UK 2008 The British journal of cancer Vol.98 No.8

We designed a phase I/II trial of S-1 combined with weekly docetaxel to determine the maximum tolerated dose (MTD) and recommended dose (RD) and to evaluate the efficacy and toxicity in metastatic gastric carcinoma (MGC). Patients with measurable disease received S-1 orally b.i.d. on days 1–14 and docetaxel intravenously on days 1 and 8 every 3 weeks. In phase I (n=30), each cohort received escalating doses of S-1 (30–45 mg m<SUP>−2</SUP> b.i.d.) and docetaxel (25–40 mg m<SUP>−2</SUP>); MTD was 45 mg m<SUP>−2</SUP> b.i.d. S-1/35 mg m<SUP>−2</SUP> docetaxel and RD was 40 mg m<SUP>−2</SUP> b.i.d. S-1/35 mg m<SUP>−2</SUP> docetaxel. Dose-limiting toxicities included grade 3 elevated liver enzymes, gastric perforation, grade 3 diarrhoea/fatigue, febrile neutropenia with grade 3 anorexia/fatigue, and neutropenic infection with grade 3 stomatitis/anorexia. In phase II (n=52), the overall response rate was 66.7% (95% confidence interval (CI): 53.8–79.6%) and the median time to progression and overall survival were 6.5 months (95% CI: 4.9–8.1) and 13.7 months (95% CI: 9.9–17.5), respectively. The most common grade 3/4 toxicity was neutropenia (29.4%), and febrile neutropenia/neutropenic infection occurred in 19.6% of patients. Non-haematological toxicities were generally mild. There was one treatment-related death due to pneumonitis. S-1 combined with weekly docetaxel is active in MGC with moderate toxicities.British Journal of Cancer (2008) 98, 1305–1311. doi:10.1038/sj.bjc.6604312 www.bjcancer.com Published online 25 March 2008

Geotechnical Characteristics of Marine Clay in Busan New Port

Chung, S.G.,Ryu, C.K.,Beak, S.H.,Huh, D.Y.,Jo, K.Y.,Lee, N.K.,Ninjgarav 東亞大學校建設技術硏究所 2004 硏究論文集 Vol.28 No.1

Since early 1990s reclamation projects in Busan and its vicinity in Nakdong River plain have been performed for industrial and residential complexes. As well it has started to build a new port (Busan Newport) due to increase in overloads of Busan port since late 1990s. In the area the sedimentary deposit is composed of soft clay of about 30m thick, thin sand layer of 3-4m thick, hard clayey soil, and then basal conglomerates and sandy sediments, total thickness of which is about 70m at the maximum under seawater. For the huge project many contract companies have simultaneously performed geotechnical investigations to get design parameters. Based on the harmful experiences gained by the previous projects, it was also required to pay careful attention to sampling and laboratory and field tests for the project. Nevertheless the results of laboratory tests were so scattered and then resulted in difficulty to evaluate the design parameters. Existing data has been reviewed to evaluate the validity or cause of their variation. In addition geological study, sampling and soil tests have been carefully carried out at a few locations. Using the results the clay would be effectively characterized for depositional environment and its relation to soil properties.

Ethanol-induced liver injury and changes in sulfur amino acid metabolomics in glutathione peroxidase and catalase double knockout mice

Kim, S.J.,Lee, J.W.,Jung, Y.S.,Kwon, D.Y.,Park, H.K.,Ryu, C.S.,Kim, S.K.,Oh, G.T.,Kim, Y.C. Elsevier Science Publishers 2009 Journal of hepatology Vol.50 No.6

Background/Aims: Oxidative stress via generation of reactive oxygen species is suggested to be the major mechanism of alcohol-induced liver injury. We investigated the effects of glutathione peroxidase-1 and catalase double deficiency (Gpx-1<SUP>-/-</SUP>/Cat<SUP>-/-</SUP>) on liver injury and changes in the sulfur amino acid metabolism induced by binge ethanol administration. Methods: Ethanol (5g/kg) was administered orally to the wild-type and the Gpx-1<SUP>-/-</SUP>/Cat<SUP>-/-</SUP> mice every 12h for a total of three doses. Mice were sacrificed 6h after the final dose. Results: The Gpx-1/Cat deficiency alone increased malondialdehyde levels in liver significantly. Hepatic methionine adenosyltransferase (MAT) activity and S-adenosylmethionine levels were decreased, however, glutathione contents were not changed. Ethanol administration to the Gpx-1<SUP>-/-</SUP>/Cat<SUP>-/-</SUP> mice increased the elevation of serum alanine aminotransferase activity, plasma homocysteine levels, hepatic fat accumulation and lipid peroxidation compared with the wild-type animals challenged with ethanol. Also the reduction of MAT activity and S-adenosylmethionine levels was enhanced, but MATI/III expression was increased significantly. Conclusions: The results indicate that Gpx-1 and Cat have critical roles in the protection of liver against binge ethanol exposure. Augmentation of ethanol-induced oxidative stress may be responsible for the impairment of the transsulfuration reactions and the aggravation of acute liver injury in the Gpx-1<SUP>-/-</SUP>/Cat<SUP>-/-</SUP> mice.