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H. W. Jeong,S. M. Seo,B. G. Choi,Y. S. Choi.,Y. K. Ahn,이재현 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.5
A directionally solidified CM247LC alloy was exposed at 871 °C and 982 °C for 1000 h, 5000 h, and 10000h under free stress in order to study the effect of microstructural degradation on the creep properties. None of the specimens exposed at temperatures up to 10000 h produced any kind of topologically close-packed phases because of the excellent phase stability of CM247LC alloy. The plate-like M6C carbide was formed only at exposure of 982 °C for 10000 h through a decomposition reaction between γ and MC. Moreover, an M23C6 carbide layer was observed between the M6C and the matrix. The exposure at 982°C for 5000 h and 10000 h had a spontaneous rafting of γ′ under free stress, while the exposure at 871 °C for 1000 h, 5000 h,and 10000 h had a non-rafted structure. The spontaneous rafted structure resulted in a drastic decrease in creep life. A 3-dimensional morphology of γ′ in the as-crept specimens, which were pre-exposed at 982 °C for 5000 h and 10000 h, had a non-rafted structure. This microstructural feature proves that the significant decrease in creep life of the specimen resulted from a loss of coherency between γ and γ′.
Choi, J.G.,Kang, H.M.,Kim, M.C.,Paek, M.R.,Kim, H.R.,Kim, B.S.,Kwon, J.H.,Kim, J.H.,Lee, Y.J. Elsevier Scientific Pub. Co 2012 Veterinary microbiology Vol.155 No.2
The H3 subtype avian influenza virus (AIV) is one of the most frequently isolated subtypes in domestic ducks, live poultry markets, and wild birds in Korea. In 2002-2009, a total of 45 H3 subtype AIVs were isolated from the feces of clinically normal domestic ducks (n=28) and wild birds (n=17). The most prevalent subtypes in domestic ducks were H3N2 (35.7%), H3N6 (35.7%), H3N8 (25.0%), and H3N1 (3.6%, novel subtype in domestic duck in Korea). In contrast, H3N8 (70.6%) is the most prevalent subtype in wild birds in Korea. In the phylogenetic analysis, HA genes of the Korean H3 AIVs were divided into 3 groups (Korean duck, wild bird 1, and wild bird 2) and all viruses of duck origin except one were clustered in a single group. However, other genes showed extensive diversity and at least 17 genotypes were circulating in domestic ducks in Korea. When the analysis expanded to viruses of wild bird origin, the genetic diversity of Korean H3 AIVs became more complicated. Extensive reassortments may have occurred in H3 subtype influenza viruses in Korea. When we inoculated chickens and ducks with six selected viruses, some of the viruses replicated efficiently without pre-adaptation and shed a significant amount of viruses through oropharyngeal and cloacal routes. This raised concerns that H3 subtype AIV could be a new subtype in chickens in Korea. Continuous surveillance is needed to prepare the advent of a novel subtype AIV in Korea.
Kim, M.C.,Lee, J.W.,Choi, H.J.,Lee, Y.N.,Hwang, H.S.,Lee, J.,Kim, C.,Lee, J.S.,Montemagno, C.,Prausnitz, M.R.,Kang, S.M. Elsevier Science Publishers 2015 Journal of controlled release Vol.210 No.-
A broadly cross-protective influenza vaccine that can be administrated by a painless self-immunization method would be a value as a potential universal mass vaccination strategy. This study developed a minimally-invasive microneedle (MN) patch for skin vaccination with virus-like particles containing influenza virus heterologous M2 extracellular (M2e) domains (M2e5x VLPs) as a universal vaccine candidate without adjuvants. The stability of M2e5x VLP-coated microneedles was maintained for 8weeks at room temperature without losing M2e antigenicity and immunogenicity. MN skin immunization induced strong humoral and mucosal M2e antibody responses and conferred cross-protection against heterosubtypic H1N1, H3N2, and H5N1 influenza virus challenges. In addition, M2e5x VLP MN skin vaccination induced T-helper type 1 responses such as IgG2a isotype antibodies and IFN-γ producing cells at higher levels than those by conventional intramuscular injection. These potential immunological and logistic advantages for skin delivery of M2e5x VLP MN vaccines could offer a promising approach to develop an easy-to-administer universal influenza vaccine.
Surveillance of avian influenza virus in wild bird fecal samples from South Korea, 2003-2008.
Kang, H M,Jeong, O M,Kim, M C,Kwon, J S,Paek, M R,Choi, J G,Lee, E K,Kim, Y J,Kwon, J H,Lee, Y J [Wildlife Disease Association] 2010 JOURNAL OF WILDLIFE DISEASES Vol.46 No.3
<P>We analyzed the results from nationwide surveillance of avian influenza (AI) from birds in South Korea's major wild bird habitats and the demilitarized zone of South Korea, 2003-2008. Of 28,214 fecal samples analyzed, 225 yielded influenza viruses, for a prevalence of 0.8%. Hemagglutinin (HA) subtypes H1-H12 and all nine neuraminidase (NA) subtypes were detected. The dominant HA subtypes were H6, H1, and H4, and the most common NA subtypes were N2, N1, and N6. Among the 38 HA/NA subtype combinations, the most common were H4N6, H6N1, and H5N2. Thirty-seven low-pathogenic AI (LPAI) viruses of the H5 and H7 subtype were detected. Among them, we identified bird species for 16 H5- and H7-positive fecal samples using a DNA bar-coding system instituted in 2007; all birds were identified as Anseriformes. The HA gene of the H5 wild bird isolates belonged to the Eurasian avian lineage, and could be clearly distinguished from the sublineage H5N1 highly pathogenic AI (HPAI) of the Eurasian and American avian lineages. Whereas H7 LPAI viruses did not group as a separate sublineage with H7 HPAI viruses, H7 isolates were closely related with the Eurasian avian lineage.</P>
Park, H.H.,Yu, H.J.,Kim, S.,Kim, G.,Choi, N.Y.,Lee, E.H.,Lee, Y.J.,Yoon, M.Y.,Lee, K.Y.,Koh, S.H. Elsevier BV 2016 NeuroToxicology Vol.55 No.-
<P>Oxidative stress is a well-known pathogenic mechanism of a diverse array of neurological diseases, and thus, numerous studies have attempted to identify antioxidants that prevent neuronal cell death. GV1001 is a 16-amino-acid peptide derived from human telomerase reverse transcriptase (hTERT). Considering that hTERT has a strong antioxidant effect, whether GV1001 also has an antioxidant effect is a question of interest. In the present study, we aimed to investigate the effects of GV1001 against oxidative stress in neural stem cells (NSCs). Primary culture NSCs were treated with different concentrations of GV1001 and/or hydrogen peroxide (H2O2) for various time durations. The H2O2 decreased the viability of the NSCs in a concentration-dependent manner, with 200 mu M H2O2 significantly decreasing both proliferation and migration. However, treatment with GV1001 rescued the viability, proliferation and migration of H2O2 injured NSCs. Consistently, free radical levels were increased in rat NSCs treated with H2O2, while co-treatment with GV1001 significantly reduced these levels, especially the intracellular levels. In addition, GV1001 restored the expression of survival-related proteins and reduced the expression of death associated ones in NSCs treated with H2O2. In conclusion, GV1001 has antioxidant and neuroprotective effects in NSCs following treatment with H2O2, which appear to be mediated by scavenging free radicals, increasing survival signals and decreasing death signals. (C) 2016 Elsevier B.V. All rights reserved.</P>
Kim, Y.I.,Park, S.J.,Kwon, H.I.,Kim, E.H.,Si, Y.J.,Jeong, J.H.,Lee, I.W.,Nguyen, H.D.,Kwon, J.J.,Choi, W.S.,Song, M.S.,Kim, C.J.,Choi, Y.K. Elsevier Science 2017 INFECTION GENETICS AND EVOLUTION Vol.53 No.-
<P>During the outbreaks of highly pathogenic avian influenza (HPAI) H5N6 viruses in 2016 in South Korea, novel H5N8 viruses were also isolated from migratory birds. Phylogenetic analysis revealed that the HA gene of these H5N8 viruses belonged to clade 2.3.4.4, similarly to recent H5Nx viruses, and originated from A/Brk/Korea/Gochang1/14(H5N8), a minor lineage of H5N8 that appeared in 2014 and then disappeared. At least four reassortment events occurred with different subtypes (H5N8, H7N7, H3N8 and H10N7) and a chicken challenge study revealed that they were classified as HPAI viruses according to OIE criteria. (C) 2017 Elsevier B.V. All rights reserved.</P>
Lee, J.H.,Pascua, P.N.Q.,Decano, A.G.,Kim, S.M.,Park, S.J.,Kwon, H.I.,Kim, E.H.,Kim, Y.I.,Kim, H.,Kim, S.Y.,Song, M.S.,Jang, H.K.,Park, B.K.,Choi, Y.K. Elsevier Science 2015 INFECTION GENETICS AND EVOLUTION Vol.34 No.-
In 2011-2012, contemporary North American-like H3N2 swine influenza viruses (SIVs) possessing the 2009 pandemic H1N1 matrix gene (H3N2pM-like virus) were detected in domestic pigs of South Korea where H1N2 SIV strains are endemic. More recently, we isolated novel reassortant H1N2 SIVs bearing the Eurasian avian-like swine H1-like hemagglutinin and Korean swine H1N2-like neuraminidase in the internal gene backbone of the H3N2pM-like virus. In the present study, we clearly provide evidence on the genetic origins of the novel H1N2 SIVs virus through genetic and phylogenetic analyses. In vitro studies demonstrated that, in comparison with a pre-existing 2012 Korean H1N2 SIV [A/swine/Korea/CY03-1½012 (CY03-1½012)], the 2013 novel reassortant H1N2 isolate [A/swine/Korea/CY0423/2013 (CY0423-12/2013)] replicated more efficiently in differentiated primary human bronchial epithelial cells. The CY0423-12/2013 virus induced higher viral titers than the CY03-1½012 virus in the lungs and nasal turbinates of infected mice and nasal wash samples of ferrets. Moreover, the 2013 H1N2 reassortant, but not the intact 2012 H1N2 virus, was transmissible to naive contact ferrets via respiratory-droplets. Noting that the viral precursors have the ability to infect humans, our findings highlight the potential threat of a novel reassortant H1N2 SIV to public health and underscore the need to further strengthen influenza surveillance strategies worldwide, including swine populations.
Park, J.K.,Lee, D.H.,Cho, C.H.,Yuk, S.S.,To, E.O.,Kwon, J.H.,Noh, J.Y.,Kim, B.Y.,Choi, S.W.,Shim, B.S.,Song, M.K.,Lee, J.B.,Park, S.Y.,Choi, I.S.,Song, C.S. Elsevier Scientific Pub. Co 2014 Veterinary microbiology Vol.169 No.3
Avian influenza virus (AIV) subtype H9N2 has been evolving rapidly and vaccine escape variants have been reported to cause circulation of infections and economic losses. In the present study, we developed and evaluated ectodomain of the AIV matrix 2 (M2e) protein as a supplementing antigen for oil-based inactivated H9N2 vaccine to increase resistance against vaccine escape variants. AIV H9N2 M2e antigen was expressed in Escherichia coli and supplemented to inactivated H9N2 oil emulsion vaccine. Specific pathogen-free chickens received a single injection of inactivated H9N2 oil emulsion vaccines with or without M2e supplementation. At three weeks post vaccination, hemagglutination inhibition tests and enzyme-linked immunosorbent assays were performed to determine serological immune responses. Challenge study using a vaccine escape H9N2 variant was performed to evaluate the efficacy of M2e supplementation. M2e antigen supplemented in oil emulsion vaccine was highly immunogenic, and a single M2e-supplemented vaccination reduced challenge virus replication and shedding more effectively than non-supplemented vaccination.
Kong, T. Y.,Kim, J. H.,Choi, W. G.,Lee, J. Y.,Kim, H. S.,Kim, J. Y.,In, M. K.,Lee, H. S. Springer Science + Business Media 2017 Analytical and bioanalytical chemistry Vol.409 No.6
<P>MAM-2201 is a synthetic cannabinoid that is increasingly found in recreational drug abusers and cases of severe intoxication. Thus, characterization of the metabolic pathways of MAM-2201 is necessary to predict individual pharmacokinetics and toxicity differences, and to avoid toxic drug-drug interactions. Collectively, 19 phase 1 metabolites of MAM-2201 were identified using liquid chromatography-Orbitrap mass spectrometry following human liver microsomal incubations in the presence of NADPH: 7 hydroxy-MAM-2201 (M1-M7), 4 dihydroxy-MAM-2201 (M8-M11), dihydrodiol-MAM-2201 (M12), N-(5-hydroxypentyl)-MAM-2201 (M13), hydroxy-M13 (M14), N-dealkyl-MAM-2201 (M15), 2 hydroxy-M15 (M16, M17), MAM-2201 N-pentanoic acid (M18), and hydroxy-M18 (M19). On the basis of intrinsic clearance values in human liver microsomes, hydroxy-MAM-2201 (M1), N-(5-hydroxypentyl)-MAM-2201 (M13), and hydroxy-M13 (M14) were the major metabolites. Based on an enzyme kinetics study using human cDNA-expressed cytochrome P450 (CYP) enzymes and an immunoinhibition study using selective CYP antibodies in human liver microsomes, CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 enzymes were responsible for MAM-2201 metabolism. The CYP3A4 enzyme played a prominent role in MAM-2201 metabolism, and CYP1A2, CYP2B6, CYP2C8, and CYP2C9 enzymes played major roles in the formation of some metabolites. MAM-2201 is extensively metabolized by multiple CYP enzymes, indicating that MAM-2201 and its metabolites should be used as markers of MAM-2201 abuse and toxicity.</P>