<i>Rhodococcus aerolatus</i> sp. nov., isolated from subarctic rainwater

Hwang, C. Y.,Lee, I.,Cho, Y.,Lee, Y. M.,Baek, K.,Jung, Y.-J.,Yang, Y. Y.,Lee, T.,Rhee, T. S.,Lee, H. K. International Union of Microbiological Societies 2015 International journal of systematic and evolutiona Vol.65 No.2

<P>A Gram-stain-positive, rod-shaped and non-motile strain, designated PAMC 27367<SUP>T</SUP>, was isolated from rainwater collected on the Bering Sea. Analysis of the 16S rRNA gene sequence of the strain showed an affiliation with the genus <I>Rhodococcus</I>. Phylogenetic analyses revealed that strain PAMC 27367<SUP>T</SUP> formed a robust clade with the type strains of <I>Rhodococcus rhodnii</I>, <I>Rhodococcus aetherivorans</I> and <I>Rhodococcus ruber</I> with 16S rRNA gene sequence similarities of 96.3 %, 95.8 % and 95.5 %, respectively. Cells of the strain grew optimally at 25 °C and at pH 6.5–7.0 in the presence of 0–2 % (w/v) sea salts. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and three unknown phospholipids. The major cellular fatty acids (>10 %) were iso-C<SUB>16 : 0</SUB>, C<SUB>17 : 1</SUB>ω8<I>c</I> and 10-methyl C<SUB>17 : 0</SUB>. Cell wall analysis showed that strain PAMC 27367<SUP>T</SUP> contained <I>meso</I>-diaminopimelic acid. The genomic DNA G+C content was 77.1 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data presented here, we propose a novel species with the name <I>Rhodococcus</I> <I>aerolatus</I> sp. nov., with PAMC 27367<SUP>T</SUP> ( = KCTC 29240<SUP>T</SUP> = JCM 19485<SUP>T</SUP>) as the type strain.</P>

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>).

Spongiibacter tropicus sp. nov., isolated from a Synechococcus culture

Hwang, C. Y.,Cho, B. C. Microbiology Society 2009 International journal of systematic and evolutiona Vol.59 No.9

<P>Two Gram-staining-negative, rod-shaped and non-motile strains, designated CL-CB221T and CL-CB467, were isolated from a Synechococcus culture derived from tropical surface water of the Pacific Ocean. The 16S rRNA gene sequences of the two strains were identical, and it was found that they belonged to the class Gammaproteobacteria, with Spongiibacter marinus HAL40bT as their closest relative (similarity of 96.3%). Both strains grew optimally at 30-35 degrees C and pH 7-8 in the presence of 3-4% (w/v) NaCl. The major cellular fatty acids were C18:1omega7c, C17:1omega8c, C16:0 and summed feature 3 (C16:1omega7c and/or iso-C15:0 2-OH). The genomic DNA G+C contents were 57.7 and 57.8 mol%, respectively. DNA-DNA hybridization experiments revealed high values (97+/-2%) for relatedness between strains CL-CB221T and CL-CB467, which suggested that these two strains belong to a single species. Based on the phylogenetic, chemotaxonomic and phenotypic data presented, it is proposed that strains CL-CB221T and CL-CB467 represent a novel species of the genus Spongiibacter, for which the name Spongiibacter tropicus sp. nov. is proposed. The type strain is CL-CB221T (=KCCM 90065T=DSM 19543T).</P>

Lipopolysaccharide-binding and neutralizing activities of surfactin C in experimental models of septic shock

Hwang, Y.H.,Park, B.K.,Lim, J.H.,Kim, M.S.,Park, S.C.,Hwang, M.H.,Yun, H.I. North-Holland ; Elsevier Science Ltd 2007 european journal of pharmacology Vol.556 No.1

To evaluate the anti-endotoxin activity of surfactin C, we studied its lipopolysaccharide-binding activity in vitro and therapeutic efficacy in experimental models of gram-negative septic shock. The ability of surfactin C to bind LPS from Escherichia coli O111:B4 was determined using a limulus chromogenic assay. Male ICR mice and Sprague-Dawley rats were given intraperitoneal administration of 1x10<SUP>9</SUP> colony forming units of E. coli ATCC 25922. After bacterial challenge, all animals were randomized to receive intraperitoneally saline, polymyxin B or surfactin C. Surfactin C not only completely bound to the LPS (its median effective concentration being 13.75 μM) but also improved the survival and reduced of the number of inoculated bacteria in the mouse model of septic shock. Surfactin C reduced the plasma endotoxin, tumor necrosis factor-α and nitric oxide levels in response to septic shock in rats.

Low Temperature Oligomerization of Ethylene over Ni/Al-KIT-6 Catalysts

Hwang, A.,Kim, S.,Kwak, G.,Kim, S. K.,Park, H. G.,Kang, S. C.,Jun, K. W.,Kim, Y. T. Springer Science + Business Media 2017 Catalysis letters Vol.147 No.6

<P>In this paper, we have studied the oligomerization of ethylene with a liquid heptane solvent over bifunctional Ni catalysts in a continuous flow reactor. We have prepared an Al-containing KIT-6 silica that was used as a support after calcination in the temperature range of 300-900 A degrees C. The Ni/Al-KIT-6 catalysts had uniform mesopores with diameters in the range of 5.4-6.3 nm, excepting Ni/Al-KIT-6 (900). The calcination temperature of Al-KIT-6 support changed the surface acidity as well as the interaction of Ni2+ and acid sites for the Ni catalysts, as determined by temperature-programmed desorption of ammonia, temperature-programmed reduction, infrared spectroscopy after the adsorption of pyridine, solid-state Al-27 magic-angle spinning nuclear magnetic resonance spectroscopy, and X-ray adsorption spectroscopy. Among the tested catalysts, the Ni/Al-KIT-6 (300) showed the highest ethylene conversion because of the increased intimate contact between Ni2+ and acid sites. The strong interaction of Ni2+ species and the support is not effective in increasing active sites for ethylene conversion. The Ni/Al-KIT-6 catalysts produced internal linear C4 and C6 olefins with high selectivity. The Ni/Al-KIT-6 (300) had 2.2-6.1 times lower selectivities toward 2-ethyl-1-butene than other catalysts at similar ethylene conversions. The reaction product mixture showed that the Ni/Al-KIT-6 catalysts shifted the product distribution towards acid-catalyzed oligomerization/cracking/realkylation products (i.e. C3, C7, C7, and C8+ olefins) as the concentration of Bronsted acid sites increased. Among the tested catalysts, the Ni/Al-KIT-6 (300) showed the highest yield of C4 and C6 olefins (78.3%).</P>

2, 4-Thiazolidindion Induced Plasticity of Myoblast (C2C12) and Satellite Cells (Porcine) - A Comparative Study

Singh, N.K.,Chae, H.S.,Hwang, I.H.,Yoo, Y.M.,Ahn, C.N.,Lee, H.J.,Park, H.J.,Chung, H.Y. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.7

This study was conducted to determine the difference between satellite cells (porcine) and myoblasts (C2C12) in their differentiation under the influence of 2, 4-thiazolidindion. C2C12 myoblast cells and porcine satellite cells (isolated from 10 d old $Landrace{\times}Duroc$ piglets) were grown to absolute confluency. Post confluent cells (day 0) were further exposed to adipogenic induction medium along with 2, 4-thiazolidindion ($8{\mu}M$) for 2 d. Thereafter, cells were exposed to 2, 4-thiazolidindion alone every 2 d till day 10 and analysed. The control was cultured in differentiation medium without any treatment. Increased (p<0.05) expression of transcriptional factors i.e. C/EBP-${\alpha}$ and PPAR-${\gamma}$ and transition of cells to adipocyte morphology was noticed from 2 d and 4 d onwards in satellite cells (Porcine) and myoblasts (C2C12) respectively. Myogenesis was observed to be suppressed completely in case of satellite cells compared to myoblasts in response to 2, 4-thiazolidindion. Pax-7 (transcriptional factor) appeared as a sole entity to satellite cells only, as it was not identified in case of myoblasts. Although both the cells were converting to adipoblasts, the degree of their conversion was different in response to 2, 4-thiazolidindion. Therefore, the hypothesis that satellite cells contribute various domains to the growing myoblasts appeared obscured and found to be dependent on the proliferative energy/or degree of fusion. However, it revealed satellite cells as currency to myoblasts/muscle.

Conversion of C2C12 Myoblast into Adipoblast with Thiazolidinediones - A Possible Basis for Intramuscular Fat Generation in Meat Animals

Singh, N.K.,Chae, H.S.,Hwang, I.H.,Yoo, Y.M.,Ahn, C.N.,Lee, H.J.,Park, H.J.,Chung, H.Y. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.3

Thiazolidinediones (TZDs) act as potent activators of the adipose differentiation program in established preadipose cell lines. TZD's have also been investigated in diabetic patients and reported to act as PPAR-${\gamma}$ ligands. In this report, the effects of TZDs on the differentiation pathway of myoblasts have been investigated. C2C12 mouse myoblasts were grown in Dulbecco's Modified Eagles medium for 4-5 days until they reached almost 100% confluency. Post-confluent cells (day 0) were further exposed to adipogenic induction medium along with TZDs for 48 hours. Thereafter, cells were exposed only to TZDs every 48 h until day 10. The control was provided with differentiation medium without any treatment. Alterations in the cells during the differentiation programme were analyzed on the basis of fusion index, oil-red-o staining, adipocyte index, adipocyte stain uptake measurement, immuno-histochemistry and western blotting. Exposure of C2C12 mouse myoblasts to TZDs prevented the expression of myosin heavy chain with parallel increase in the expression of C/EBP-${\alpha}$ and PPAR-${\gamma}$ and acquisition of adipocyte morphology, thus abolishing the formation of multinucleated myotubes. TZDs exert their adipogenic effects only in non-terminally differentiated myoblasts; myotubes were insensitive to the compound. Continuous exposure (at least 4-5 doses) to inducers after the growth arrest was essential to provide a sustained environment to the cells converting to fully matured adipoctyes. The results indicate that TZDs specifically converted the differentiation pathway of myoblasts into that of adipoblasts.

Bioequivalence Study of a New Fixed-dose Combination Tablet Containing S-Amlodipine Nicotinate and Olmesartan Medoxomil in Healthy Korean Male Subjects

Oh, M.J.,Hwang, H.H.,Kim, H.G.,Lee, G.H.,Cho, Y.S.,Lee, S.Y.,Kang, S.Y.,Cho, K.H.,Lee, Y.Y.,Lee, Y.J.,Jang, C.G.,Lee, S.Y. Excerpta Medica] ; Elsevier Science Ltd 2017 Clinical therapeutics Vol.39 No.7

Purpose: A fixed-dose combination (FDC) pill of amlodipine (relatively old calcium channel blocker as dihydropyridine) and olmesartan (relatively new angiotensin II receptor blocker) is used for hypertension that is not adequately controlled with a single-formulation drug. Because the FDC is a one-pill formulation, and amlodipine and olmesartan have different mechanisms of action, it is expected to improve patients' medication compliance and have an increased blood pressure-lowering efficacy. The purpose of this study was to assess the safety profile and the bioequivalence of two different FDC formulations [amlodipine besylate/olmesartan medoxomil 10/40 mg (reference product) and S-amlodipine nicotinate/olmesartan medoxomil 5/40 mg (test product)]. Methods: A randomized, open-label, single-dose, 2-treatment, 2-way, and 2-period crossover study, including a 3-week washout period, was performed in 32 healthy Korean male volunteers. To analyze the concentration of S-amlodipine or olmesartan, plasma samples were collected up to 144 hours after the dose for S-amlodipine and 48 hours after the dose for olmesartan. Pharmacokinetic parameters, including the C<SUB>max</SUB> and the area under the curve from time 0 to the last measurable concentration (AUC<SUB>0-last</SUB>) for the time versus concentration plot, were calculated. Analysis of variance for bioequivalence was conducted using C<SUB>max</SUB> and AUC<SUB>0-last</SUB> converted to log scale, and the mean ratios and 90% CIs were determined. Safety data included analysis of adverse events (AEs), vital signs, physical examinations, clinical laboratory test, and 12-lead ECGs. Findings: Of the 32 enrolled participants, 29 healthy volunteers completed the study. For both S-amlodipine and olmesartan, the main pharmacokinetic parameters were all within the acceptable range for regulatory bioequivalence. The 90% CIs for the geometric mean ratios of C<SUB>max</SUB> and AUC<SUB>0-last</SUB> were 0.8766 to 0.9760 and 0.8288 to 0.9224, respectively, for S-amlodipine and 0.9097 to 1.1229 and 0.8904 to 1.0407, respectively, for olmesartan. Hypotension was the most frequent AE, and it was observed in 4 volunteers with the test product and 7 volunteers with the reference product. Both the test and reference formulations were well tolerated. Implications: The present study demonstrates that the newly developed FDC product (test drug) and the conventional FDC product (reference drug) have comparable pharmacokinetic characteristics in healthy adult male volunteers. Both the test and reference products indicated good tolerance in this population, and no serious AEs were observed.

Carbon-coated boron using low-cost naphthalene for substantial enhancement of J_c in MgB₂ superconductor

Ranot, Mahipal,Shinde, K.P.,Oh, Y.S.,Kang, S.H.,Jang, S.H.,Hwang, D.Y.,Chung, K.C. The Korea Institute of Applied Superconductivity a 2017 한국초전도저온공학회논문지 Vol.19 No.3

Carbon coating approach is used to prepare carbon-doped $MgB_2$ bulk samples using low-cost naphthalene ($C_{10}H_8$) as a carbon source. The coating of carbon (C) on boron (B) powders was achieved by direct pyrolysis of naphthalene at $120^{\circ}C$ and then the C-coated B powders were mixed well with appropriate amount of Mg by solid state reaction method. X-ray diffraction analysis revealed that there is a noticeable shift in (100) and (110) Bragg reflections towards higher angles, while no shift was observed in (002) reflections for $MgB_2$ doped with carbon. As compared to un-doped $MgB_2$, a systematic enhancement in $J_c(H)$ properties with increasing carbon doping level was observed for naphthalene-derived C-doped $MgB_2$ samples. The substantial enhancement in $J_c$ is most likely due to the incorporation of C into $MgB_2$ lattice and the reduction in crystallite size, as evidenced by the increase in the FWHM values for doped samples.

Ionic and thermo-switchable polymer-masked mesoporous silica drug-nanocarrier: High drug loading capacity at 10^oC and fast drug release completion at 40^oC

Eltohamy, M.,Seo, J.W.,Hwang, J.Y.,Jang, W.C.,Kim, H.W.,Shin, U.S. Elsevier 2016 Colloids and surfaces. B, Biointerfaces Vol.144 No.-

<P>The preparation of the ideal smart drug-delivery systems were successfully achieved by the in situ co-polymerization of a vinyl group-functionalized mesoporous silica nanoparticle (f-MSN) with 1-butyl-3-vinyl imidazolium bromide (BVIm) and N-isopropylacrylamide (NIPAAm) monomers. The thickness of the capping copolymer layer, poly(NIPAAm-co-BVIm) (p-NIBIm), was controlled at between 2.5 nm and 5 nm, depending on the monomers/f-MSN ratio in the reaction solution. The finally obtained smart drug-delivery systems are named as p-MSN2.5 and p-MSN5.0 (MSNs integrated by 2.5 nm and 5 nm p-NIBIm layer in thickness). The key roles of the mesoporous-silica-nanoparticle (MSN) core and the p-NIBIm shell are drug-carrying (or containing) and pore-capping, respectively, and the latter has an on/off function that operates in accordance with temperature changes. According to the swelling- or shrinking-responses of the smart capping copolymer to temperature changes between 10 degrees C and 40 degrees C, the loading and releasing patterns of the model drug cytochrome c were studied in vitro. The developed system showed interesting performances such as a cytochrome-c-loading profile (loading capacity for 3 h = 26.3% and 19.8% for p-MSN2.5 and p-MSN5.0, respectively) at 10 degrees C and a cytochrome-c-releasing profile (releasing efficiency = > 95% within 3 days and 4days for p-MSN2.5 and p-MSN5.0, respectively) at 40 degrees C. The cytotoxicity of the drug delivery systems, p-MSN2.5 and p-MSN5.0 (in the concentration range of <0.125 mg/mL without drug), for human embryonic kidney (HEK 293) cells were minimal in vitro compared with that of a blank MSN. These results may be reasonably applied in the field of specified drug delivery. (C) 2016 Elsevier B.V. All rights reserved.</P>