O-free polyacrylonitrile doping to improve the J_c(B) and H_c2 of MgB₂ wires

Hwang, S.M.,Sung, K.,Choi, J.H.,Kim, W.,Joo, J.,Lim, J.H.,Kim, C.J.,Park, Y.S.,Kim, D.H. North-Holland 2010 Physica. C, Superconductivity Vol.470 No.20

We selected polyacrylonitrile (PAN, -[C<SUB>3</SUB>H<SUB>3</SUB>N]-) as an O-free organic dopant and fabricated C-doped MgB<SUB>2</SUB> wires by in situ and powder-in-tube techniques. 0-5 wt.% PAN powders were uniformly mixed with B powder using a liquid mixing method. The precursor powders were mixed with Mg powder, filled into Fe tubes, and then drawn into wires. Sintering was performed at 900<SUP>o</SUP>C for 1h in a flowing Ar gas. The PAN doping decreased the critical temperature (T<SUB>c</SUB>) and a-axis lattice parameter, but significantly improved the critical current density (J<SUB>c</SUB>) in high fields, upper critical field (H<SUB>c2</SUB>), and irreversibility field (H<SUB>irr</SUB>) performances. These results are attributed to the replacement of B sites with C by the PAN doping. Furthermore, as expected, the MgO amount did not increase as the doping content increased. The J<SUB>c</SUB> of the PAN-doped MgB<SUB>2</SUB> wires was more than one order of magnitude higher than that of the undoped MgB<SUB>2</SUB> wire at 5K and 6.6T (1.46-3.82kA/cm<SUP>2</SUP> vs. 0.11kA/cm<SUP>2</SUP>).

The Effects of Stress Related Genes on Carcass Traits and Meat Quality in Pigs

H. J. Jin,B. Y. Park,J. C. Park,I. H. Hwang,S. S. Lee,S. H. Yeon,C. D. Kim,C. Y. Cho,Y. K. Kim,K. S. Min,S. T. Feng,Z. D. Li,C. K. Park,C. I. Kim 아세아·태평양축산학회 2006 Animal Bioscience Vol.19 No.2

The current study was conducted to investigate the relationship between stress related gene and meat quality in pigs. A total number of 212 three-way cross bred (Landrace-Yorkshire횞Duroc) and 38 Duroc were sampled from the Korean pig industry to determine genotype requency of porcine stress syndrome (PSS) and heat shock protein 70 kDa (HSP70) genes and their relationship with carcass traits and longissimus meat quality. Screen of HSP70 was performed by the single strand conformation polymorphism (SSCP) technique. Based on the analysis of restriction fragment length polymorphism (RFLP) in ryanodine receptor 1 (RYR1) gene, genetic disorder of PSS was related to a mutation at 18,168th (C to T) of exon 17. There was no significant difference in ultimate meat pH and backfat thickness between HSP70 K1-AA type and -BB type in pure Duroc breed. In Landrace-Yorkshire횞Duroc (L-YxD) cross bred pig, our results indicated that HSP70 derivate type in Duroc had a limited effect on backfat thickness, but L-YxD type had a noticeable linkage with HSP70 K1-AA and K3-AB. This tendency was also observed in hot carcass weight where HSP70 K1-AA and K3-AB resulted in heavier weight with 86.3 kg compared to HSP70 K1-AB and K3-BB of 74.3 kg. Results imply that stress related HSP70 genotype has a potential association with backfat thickness and carcass weight.

Synthesis and hydrogenation properties of lithium magnesium nitride

Kim, J.H.,Kang, Y.M.,Park, M.S.,Hwang, K.T. Pergamon Press ; Elsevier Science Ltd 2011 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.36 No.16

Li-Mg-N-H systems have been focused on as one of the most promising hydrogen storage systems owing to their high hydrogen contents and binary nitride, LiMgN, has a high gravimetric storage density of 8.2 wt% H<SUB>2</SUB>. We synthesized LiMgN by a hydriding thermal reaction between Mg and LiNH<SUB>2</SUB> under various H<SUB>2</SUB> pressures and a subsequent dehydrogenation reaction, and optimized conditions for the formation of pure LiMgN. The results demonstrate that pure LiMgN can be produced using hydriding thermal synthesis at 80 bar H<SUB>2</SUB> pressure and 723 K. The hydriding and dehydriding characteristics of as-synthesized LiMgN were investigated by a Sievers' type instrument. The reaction product LiMgN can be rehydrogenated by reacting with H<SUB>2</SUB> under 80 bar of hydrogen pressure at 573 K, and then released under less than 0.5 bar at 573 K. The measured H<SUB>2</SUB> capacity is about 6.8 wt% during the hydrogenation process.

Dipeptidyl petidase-IV inhibitor (gemigliptin) inhibits tunicamycin-induced endoplasmic reticulum stress, apoptosis and inflammation in H9c2 cardiomyocytes

Hwang, H.J.,Jung, T.W.,Ryu, J.Y.,Hong, H.C.,Choi, H.Y.,Seo, J.A.,Kim, S.G.,Kim, N.H.,Choi, K.M.,Choi, D.S.,Baik, S.H.,Yoo, H.J. North-Holland 2014 Molecular and cellular endocrinology Vol.392 No.1

The direct effects of dipeptidyl peptidase-IV (DPP-IV) inhibitors on endoplasmic reticulum (ER) stress-induced apoptosis and inflammation in cardiomyocytes have not been elucidated. H9c2 cell viability, which was reduced by tunicamycin, was increased after DPP-IV inhibitor gemigliptin treatment. Gemigliptin significantly decreased the tunicamycin-mediated increase in glucose regulated protein 78 (GRP78) expression and ER stress-mediated signaling molecules such as protein kinase RNA-like endoplasmic reticulum kinase (PERK)/C-EBP homologous protein (CHOP) and inositol-requiring enzyme 1α (IRE1α)/c-Jun N-terminal kinase (JNK)-p38. Furthermore, gemigliptin effectively induced Akt phosphorylation in a dose-dependent manner. Using flow cytometry and Hoechst staining, we showed that treatment with Akt inhibitor significantly blocked the anti-apoptotic effects mediated by gemigliptin. The reduction in tunicamycin-induced GRP78 level and PERK/CHOP pathway activity by gemigliptin was reversed after treatment with Akt inhibitor. In conclusion, gemigliptin effectively inhibited ER stress-induced apoptosis and inflammation in cardiomyocytes via Akt/PERK/CHOP and IRE1α/JNK-p38 pathways, suggesting its direct protective role in cardiovascular diseases.

Relationship Between K_trans and K₁ with Simultaneous Versus Separate MR/PET in Rabbits with VX2 Tumors

Lee, K. H.,Kang, S. K.,Goo, J. M.,Lee, J. S.,Cheon, G. J.,Seo, S.,Hwang, E. J. INTERNATIONAL INSTITUTE OF ANTICANCER RESEARCH 2017 Anticancer research Vol.37 No.3

<P>Background/Aim: To compare the relationship between Ktrans from DCE-MRI and K1 from dynamic (NNH3)-N-13- PET, with simultaneous and separate MR/PET in the VX-2 rabbit carcinoma model. Materials and Methods: MR/PET was performed simultaneously and separately, 14 and 15 days after VX-2 tumor implantation at the paravertebral muscle. The Ktrans and K-1 values were estimated using an in-house software program. The relationships between Ktrans and K-1 were analyzed using Pearson's correlation coefficients and linear/non-linear regression function. Results: Assuming a linear relationship, Ktrans and K-1 exhibited a moderate positive correlations with both simultaneous ( r=0.54-0.57) and separate ( r=0.53-0.69) imaging. However, while the Ktrans and K-1 from separate imaging were linearly correlated, those from simultaneous imaging exhibited a non-linear relationship. The amount of change in K-1 associated with a unit increase in Ktrans varied depending on Ktrans values. Conclusion: The relationship between K-trans and K-1 may be mis-interpreted with separate MR and PET acquisition.</P>

A study on Driving of 35W(T5) fluorescent lamp by the electronic ballast using piezoelectric transformer

L H Hwang,J H Yoo,H S Song,S K Na,H S Kim,H S Oh,S H Lee,K H Choi,M T Cho 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

Recently, 35W class Fluorescent lamps with 32㎜ tube diameter are replaced with 32W one with 26 ㎜ in diameter to conserve lamp materials and to increase luminance efficiency. Moreover, 35, 28 and 14 W fluorescent lamps with 16㎜ (T5) in diameter, which are nowadays developed, also may replace 32 W lamps again. Application of slim lamps, however, requires small sized electronic ballast to full fill the design philosophy of miniaturizing. However, the traditional magnetic ballasts operated at 50-60㎐ have been suffered from noticeable flicker, high loss, large crest factor and heavy weight. In this study, in order to solve these problems, a new type of electronic ballast, which is composed of rectifier, active power factor corrector, series resonant half bridge inverter and piezoelectric transformer, was proposed for driving T5 fluorescent lamp. Driving of piezoelectric transformer was carried out with input region for the ring electrode and output region for the dot electrode. A 35W (T5) fluorescent lamp is successfully driven by the fabricated ballast with piezoelectric transformer. After driving the lamp using the proposed electronic ballast for 20 min, the input power factor and efficiency of ballast shown 0.95 and 86%, respectively, at operating frequency of 81 k㎐. And also, the output power and temperature rise of piezoelectric transformer showed 35.07W and 20.5 , respectively.

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.

Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II

Lee, K‐,E,Kang, H‐,Y,Lee, S‐,K,Yoo, S‐,H,Lee, J‐,C,Hwang, Y‐,H,Nam, KH,Kim, J‐,S,Park, J‐,C,Kim, J‐,W Blackwell Publishing Ltd 2011 Clinical genetics Vol.79 No.4

<P>Lee K‐E, Kang H‐Y, Lee S‐K, Yoo S‐H, Lee J‐C, Hwang Y‐H, Nam KH, Kim J‐S, Park J‐C, Kim J‐W. Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II.</P><P>The dentin sialophosphoprotein (<I>DSPP</I>) gene encodes the most abundant non‐collagenous protein in tooth dentin and DSPP protein is cleaved into several segments including the highly phosphorylated dentin phosphoprotein (DPP). Mutations in the <I>DSPP</I> gene have been solely related to non‐syndromic form of hereditary dentin defects. We recruited three Korean families with dentinogenesis imperfecta (DGI) type II and sequenced the exons and exon–intron boundaries of the <I>DSPP</I> gene based on the candidate gene approach. Direct sequencing of PCR products and allele‐specific cloning of the highly repetitive exon 5 revealed novel single base pair (bp) deletional mutations (c.2688delT and c.3560delG) introducing hydrophobic amino acids in the hydrophilic repeat domain of the DPP coding region. All affected members of the three families showed exceptionally rapid pulp chambers obliteration, even before tooth eruption. Individuals with the c.3560delG mutation showed only mild, yellowish tooth discoloration, in contrast to the affected individuals from two families with c.2688delT mutation. We believe that these results will help us to understand the molecular pathogenesis of DGI type II as well as the normal process of dentin biomineralization.</P>

Bactericidal effect through non-uptake pathway with photofunctional silicon polymer that generates reactive oxygen species

Wang, K.K.,Jung, S.J.,Hwang, J.W.,Kim, B.J.,Kim, D.H.,Bae, I.K.,Jeong, S.H.,Kim, Y.R. Elsevier Sequoia 2016 Journal of photochemistry and photobiology Chemist Vol.315 No.-

<P>We report bactericidal effect of photosensitizer (H2TPP: 5,10,15,20-tetraphenyl-21H,23H-porphyrin) through non-uptake pathway and efficacy of the photofunctional silicon polymer to the decomposition of the formed biofilm and the suppression of the biofilm formation. The photoftmctional silicon polymer (PSP), which is the silicon polymer embedded with a photosensitizer, is fabricated by a simple solvent swell-encapsulation-shrink method. Reactive oxygen generation from PSP was confirmed by using the decomposition reaction of 1,3-diphnyl-isobenzofuran (DPBF). Also, singlet oxygen generation which is one of the reactive oxygen species (ROS) from PSP is directly confirmed with time and wavelength resolved singlet oxygen phosphorescence spectroscopy. For the influence study of ROS under the non-uptake condition of photosensitizer (PS to bacteria), photodynamic inactivation (PDI) effect of PSP is evaluated for Gram-positive, Gram-negative bacteria, and fungi. Those microorganisms were inactivated by PSP within 1 h under the given power of laser light (63.7 mW/cm(2)). Among the bacteria, especially, Staphylococcus aureus as the Gram-positive bacteria were completely disinfected under the given experimental condition. Furthermore, PSP successfully demonstrates the decomposition of the formed biofilm and the suppression of the biofilm formation with green light emitting diode (GLED, 3.5 mW/cm(2),lambda(max) = 517 nm, FWHM = 37 nm), which shows the practical application possibility of bactericidal material. (C) 2015 Elsevier B.V. All rights reserved.</P>

Solubility of oxcarbazepine in eight solvents within the temperature range T=(288.15-308.15)K

Nam, K.,Ha, E.S.,Kim, J.S.,Kuk, D.H.,Ha, D.H.,Kim, M.S.,Cho, C.W.,Hwang, S.J. Academic Press 2017 The Journal of chemical thermodynamics Vol.104 No.-

In this study, the solubility of oxcarbazepine in pure methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, acetonitrile, and tetrahydrofuran was analysed across the temperature range of 288.15-308.15K under atmospheric pressure by using a solid-liquid equilibrium method. The experimental values obtained data were correlated using the modified Apelblat model at each temperature. The mole fraction solubility of oxcarbazepine in all eight pure solvents increased gradually in a temperature-dependent manner. The highest mole fraction solubility of 3.08x10<SUP>-3</SUP> at 308.15K was observed for tetrahydrofuran, followed by acetone (1.82x10<SUP>-3</SUP> at 308.15K), acetonitrile (1.22x10<SUP>-3</SUP> at 308.15K), methanol (1.11x10<SUP>-3</SUP> at 308.15K), ethanol (6.17x10<SUP>-4</SUP> at 308.15K), 1-butanol (6.17x10<SUP>-4</SUP> at 308.15K), 1-propanol (6.16x10<SUP>-4</SUP> at 308.15K), and 2-propanol (4.13x10<SUP>-4</SUP> at 308.15K). The experimental solubility in all solvents correlated well with that calculated using the modified Apelblat equation across the temperature range of (288.15-308.15)K. Therefore, the experimental solubility and correlation equations established in this study could be useful during the crystallization/purification, pre-formulation, and formulation stages of oxcarbazepine production in laboratories and related industries.