Self-standing and shape-memorable UV-curing epoxy polymers for three-dimensional (3D) continuous-filament printing

Sun, H.,Kim, Y.,Kim, Y. C.,Park, I. K.,Suhr, J.,Byun, D.,Choi, H. R.,Kuk, K.,Baek, O. H.,Jung, Y. K.,Choi, H. J.,Kim, K. J.,Nam, J. D. The Royal Society of Chemistry 2018 Journal of materials chemistry. C, Materials for o Vol.6 No.12

<P>In the development of three-dimensional printable materials for high-speed and high-resolution printing, UV-curing polymers can guarantee fast and precise printing of high performance load-bearing structures, but the injected drops of the monomers tend to spread over the substrates due to their low viscosity. In this study, we imposed the self-standing and shape-memorable capability of an epoxy acrylate (EA) monomer to ensure continuous filamentary 3D printing while maintaining its low viscosity nature. Using octadecanamide (ODA) with EA, strong hydrogen-bond networks (−N−H⋯OC−, −N−CO⋯H-O-, -N-H⋯N-) were additionally achieved in the material system and the developed material distinctively exhibited rheological duality at different processing stages: a low-viscosity liquid-like behavior (viscosity of ∼50 Pa) while passing through the nozzle and a self-standing solid-like behavior (static yield stress of ∼364 Pa) right after being printed. This reversible liquid-to-solid transitional capability was quantified by viscoelastic complex moduli provided a dynamic yield stress (<I>τ</I>y,G) of 210 Pa corresponding to the upright stacking up to ∼3.2 cm (3 wt% of ODA). The time (<I>t</I>y,G) required for conformational rearrangement was evaluated to be as fast as ∼10<SUP>−2</SUP> s. After UV curing, the 3D printed layers exhibited no air pockets or weld lines at the stacked interfaces, which could guarantee excellent mechanical performance and structural integrity.</P>

An outbreak of highly pathogenic H5N1 avian influenza in Korea, 2008

Kim, H.R.,Park, C.K.,Lee, Y.J.,Woo, G.H.,Lee, K.K.,Oem, J.K.,Kim, S.H.,Jean, Y.H.,Bae, Y.C.,Yoon, S.S.,Roh, I.S.,Jeong, O.M.,Kim, H.Y.,Choi, J.S.,Byun, J.W.,Song, Y.K.,Kwon, J.H.,Joo, Y.S. Elsevier Scientific Pub. Co 2010 Veterinary microbiology Vol.141 No.3

In spite of intensive surveillance programs for the control of HPAI, an outbreak of highly pathogenic avian influenza (HPAI) H5N1 in Korea in April 2008 caused serious damage to poultry farms, as did previous outbreaks in 2003/2004 and 2006/2007. Six viruses were selected from the Korean 2008 isolates for genetic analysis, and all eight gene segments from each of the influenza viruses were sequenced. A phylogenetic analysis showed that all of the viruses were of the same virus type and that the hemagglutinin (HA) gene was clustered with that of clade 2.3.2 viruses. However, the internal and neuraminidase (NA) genes were closely related to those of the clade 2.3.4 viruses (recent human and bird isolates from Southeast Asia).

Cold-Adapted Pandemic 2009 H1N1 Influenza Virus Live Vaccine Elicits Cross-Reactive Immune Responses against Seasonal and H5 Influenza A Viruses

Jang, Y. H.,Byun, Y. H.,Lee, Y. J.,Lee, Y. H.,Lee, K.-H.,Seong, B. L. American Society for Microbiology 2012 Journal of virology Vol.86 No.10

Enhancement of the safety of live influenza vaccine by attenuating mutations from cold-adapted hemagglutinin

Lee, Y.J.,Jang, Y.H.,Kim, P.,Lee, Y.H.,Lee, Y.J.,Byun, Y.H.,Lee, K.H.,Kim, K.,Seong, B.L. 3M Company 2016 Virology Vol.491 No.-

<P>In our previous study, X-31ca-based H5N1 LAIVs, in particular, became more virulent in mice than the X-31ca MDV, possibly by the introduction of the surface antigens of highly pathogenic H5N1 influenza virus, implying that additional attenuation is needed in this cases to increase the safety level of the vaccine. In this report we suggest an approach to further increase the safety of LAIV through additional cold-adapted mutations in the hemagglutinin. The cold-adaptation of X-31 virus resulted in four amino acid mutations in the HA. We generated a panel of 7:1 reassortant viruses each carrying the hemagglutinins with individual single amino acid mutations. We examined their phenotypes and found a major attenuating mutation, N81K. This attenuation marker conferred additional temperature-sensitive and attenuation phenotype to the LAIV. Our data indicate that the cold-adapted mutation in the HA confers additional attenuation to the LAIV strain, without compromising its productivity and immune response. (C) 2016 Elsevier Inc. All rights reserved.</P>

A novel chimeric promoter that is highly responsive to hypoxia and metals

Lee, J-Y,Lee, Y-S,Kim, J-M,Kim, K L,Lee, J-S,Jang, H-S,Shin, I-S,Suh, W,Jeon, E-S,Byun, J,Kim, D-K Nature Publishing Group 2006 Gene Therapy Vol.13 No.10

To develop a potent hypoxia-inducible promoter, we evaluated the usefulness of chimeric combinations of the (Egr-1)-binding site (EBS) from the Egr-1 gene, the metal-response element (MRE) from the metallothionein gene, and the hypoxia-response element (HRE) from the phosphoglycerate kinase 1 gene. In transient transfection assays, combining three copies of HRE (3 × HRE) with either EBS or MRE significantly increased hypoxia responsiveness. When a three-enhancer combination was tested, the EBS–MRE-3 × HRE (E–M–H) gave a hypoxia induction ratio of 69. The expression induced from E–M–H-pGL3 was 2.4-fold higher than that induced from H-pGL3 and even surpassed the expression from a human cytomegalovirus promoter-driven vector. The high inducibility of E–M–H was confirmed by validation studies in different cells and by expressing other cDNAs. Gel shift assays together with functional overexpression studies suggested that increased levels of hypoxia-inducible factor 1α, metal transcription factor-1 and Egr-1 may be associated with the high inducibility of the E–M–H chimeric promoter. E–M–H was also induced by hypoxia mimetics such as Co<SUP>2+</SUP> and deferoxamine (DFX) and by hydrogen peroxide. Gene expression from the E–M–H was reversible as shown by the reduced expression of the transgene upon removal of inducers such as hypoxia and DFX. In vivo evaluation of the E–M–H in ischemic muscle revealed that erythropoietin secretion and luciferase and LacZ expression were significantly higher in the E–M–H group than in a control or H group. With its high induction capacity and versatile means of modulation, this novel chimeric promoter should find wide application in the treatment of ischemic diseases and cancer.Gene Therapy (2006) 13, 857–868. doi:10.1038/sj.gt.3302728; published online 9 February 2006

Differentiation Between Hepatocellular Carcinoma and Colorectal Cancer Liver Metastases on High-Resolution Magic Angle Spinning Spectroscopy: Preliminary Study

Kim, S. Y.,Kim, S.,Woo, C. W.,Byun, J. H.,Lee, S. S.,Lee, M. G.,Kim, H.,Lee, K. H.,Kim, Y. H.,Cho, J. Y. SPRINGER-VERLAG 2014 Applied magnetic resonance Vol.45 No.1

To explore the potential of high-resolution magic angle spinning (HRMAS) H-1 nuclear magnetic resonance (NMR) spectroscopy for differentiation and metabolite characterization of hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM), we prospectively included 21 pathologically confirmed malignant hepatic tumors (8 HCC and 13 CRLM) and 26 non-tumorous hepatic parenchyma from 26 patients who underwent hepatic tumor resection. Using intact tissue samples obtained during surgery, HRMAS H-1 NMR spectroscopy was performed at 11.7 T. All observable metabolite signals were acquired using a water-presaturated standard one-dimensional Carr-Purcell-Meiboom-Gill sequence. Metabolomic profiles contributing to the differentiation of HCC and CRLM and of each tumor and non-tumorous hepatic parenchyma were represented by orthogonal partial least squares discriminant analysis (OPLS-DA) and loading plots. Metabolite intensity normalized by total spectral intensities in both tumors was compared using student's t tests. OPLS-DA and loading plots demonstrated good separation between tumors and non-tumorous hepatic parenchyma. The metabolomic characteristics of HCC showed separation from those of CRLMs according to OPLS-DA. Compared with CRLM, HCC showed significantly elevated levels of glucose (P < 0.01) and sn-Glycero-3-phosphocholine (P < 0.01), and decreased levels of hypoxanthine (P = 0.04). HCC and CRLM could be differentiated by the metabolic profile using HRMAS H-1 NMR spectroscopy.

On confinement characteristics of the newly developed sawtooth-free plasmas in KSTAR tokamak

Byun, C.s.,Na, Y.S.,Kim, H.S.,Kim, S.H. Elsevier 2014 Current Applied Physics Vol.14 No.1

Development of advanced scenarios, an important experimental goal of the Korea superconducting tokamak advanced research (KSTAR) project, has just begun. The safety factor (q) profile is a key to achieve these advanced scenarios. Particularly the hybrid scenario, one of the advanced scenarios, can be established generally with low magnetic shear (s) at the center with central q-value above unity so to avoid sawtooth instability. This q-profile was successfully produced using early divertor formation during a plasma current ramp-up phase in KSTAR. Auxiliary heating was also employed during the current ramp-up phase to delay the inductive current diffusion to the center of the plasma. In addition to the early divertor formation method, the target q-profile was attempted to be achieved by modifying the plasma current waveform using the so-called, 'current-overshoot' method and the timing of L-mode to H-mode transition. In this work, the confinement characteristics of these sawtooth-free regimes are investigated. The global energy confinement time is calculated and compared with that of conventional H-modes in KSTAR. The confinement enhancement factor reveals that the newly developed discharges are not improved over H-modes contrary to results of other tokamaks. To investigate the reason, transport modeling is performed self-consistently with an integrated simulation package incorporating plasma equilibrium, transport, and heating and current drive. The current ramp-up phase is simulated and impact of early divertor formation, current-overshoot, and early L-H transition on the target q-profile and s/q profile is addressed. The s/q profile is found to be not improved in these discharges compared with hybrid scenarios reported in other tokamaks. Based on these results, future experimental directions are addressed to access the hybrid regimes in KSTAR.

LMI Based H<SUB>∞</SUB> Active Vibration Control of a Structure with Output Feedback

Y. B. Kim,J. H. Byun,H. J. Jeong,J. H. Yang,B. K. Jung 한국동력기계공학회 1999 한국동력기계공학회 학술대회 논문집 Vol.- No.-

Mechanical properties of Mo-Nb-Si-B quaternary alloy fabricated by powder metallurgical method

Byun, J.M.,Bang, S.R.,Kim, S.H.,Choi, W.J.,Kim, Y.D. MPR Pub. Services 2017 INTERNATIONAL JOURNAL OF REFRACTORY METALS AND HAR Vol.65 No.-

<P>In this study, niobium (Nb) was added to a Mo-Si-B alloy by a powder metallurgical method to improve the mechanical properties. First, the Mo and Nb powders were pulverized by high-energy ball milling. Then, the synthesized intermetallic compound powders, which were fabricated by continuous heat treatment under a H-2 atmosphere, were mixed with ball-milled Mo and Nb powder. Pressureless sintering was conducted at 1400 degrees C for 3 h under a H-2 atmosphere. The Vickers hardness and fracture toughness were measured to investigate the mechanical properties of the sintered Mo-Si-B and Mo-Nb-Si-B alloy. The Vickers hardness was about 425 Hv for a Mo-Nb-Si-B alloy, which was lower value of 165 Hv compared to Mo-Si-B alloy (590 Hv). On the other hand, the fracture toughness of the Mo-Nb-Si-B alloy (14.5 MPa center dot root m) greatly increased compared to that of the Mo-Si-B alloy (12.6 MPa center dot root m). (C) 2016 Elsevier Ltd. All rights reserved.</P>

돼지 대장에서 분리한 E.coli의 중금속 내성에 관한 연구

조창현,정욱진,이영수,최인실,강희옥,박남규,김명화,변미경,이현숙 경상대학교 환경보전연구소 1993 環境保全硏究所報 Vol.1 No.1

돼지의 대장에서 서식하는 466개의 대장균 균주들을 분리하여, 중금속인 Ag, Cd, Cu, Hg, Ni 및Pb에 대한 저항성을 조사 하였다. 거의 대부분의 균주들이 이들 여섯가지 중금속 모두에 강한 저항성을 보였다. 이것은 우리 주위환경의 중금속 오염 정도가 심각하다는 것을 간접적으로 나타내는 것이다. Ag, Pb 및 Hg를 함유하고 있는 고체 배지에서 균주를 성장시켰을때, colony 색깔이 중금속 자체의 광택과 같은 색깔을 나타내는 점으로 보아, 이들 중금속에 대한 저항기작은 유해한 중금속 이온을 세포내 에서 무해한 금속 형태로 전환시켜 세포내에 축적시키는 기작임을 시사하였다. 그 중 가장 높은 저항성을 나타내는 isolate 385를 Ag와 Pb를 함유한 액체배지에서 각각 배양한 뒤 세포내 Ag와 Pb 축적량을 조사한 결과, 건조세포 무게당 0.72g Ag 및 0.23g Pb를 세포내에 축적하고 있었다. 따라서, 이 균주를 유전자 조작 등의 방법으로 개발 한다면 산업 폐수내에 존재하는 이 중금속들의 제거에 효율적으로 사용할 수 있을 것이라 사료된다. We isolated E.coli from porcine intestines and examined the resistances to various heavy-metals, Ag, Cd, Cu, Hg, Ni, and Pb. The 466 isolates were resistant to the heavy-metals. Among them, 72.1% was survived in 1 mM AgNO₃, 9.3% in 80 mM AgNO₃, 95.9% in 0.6 mM Cd(NO₃)₂, 5.6% in 3 mN Cd(NO₃)₂. 95.9% in Cu(NO₃)₂, 48.5% in 0.2 mM HgCl₂, 3.4% in 0.6 mM HgCl₂, 64.4% in 5 mM NiCl₂ and 67.4% in 10 mM Pb(NO₃)₂. The isolate 385 was most resistant to silver and lead ions and the MICs of the ions were 80 mM and 11 mM, respectively. These resistances were inducible by Ag^+ and Pb^2+ ions. When isolate 385 grew in LB-agar plates containing AgNO₃ or Pb(NO₃)₂, the colony colors were changed from light yellow to deep brown. This change to brown color suggests that the resistances of 385 cells to Ag^+ and Pb^2+ ions were due to the reducing mechanism which converted them into the elementary metals(Ag^0, Pb^0) after the uptake of the ions into the cells. The resistant cells accumulated 0.72gr of Ag^0 and 0.23gr of Pb^0 per cells dry wt.