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Nagaraja, B.M.,Jung, H.,Yang, D.R.,Jung, K.D. Elsevier Science Publishers 2014 CATALYSIS TODAY - Vol.232 No.-
PtSn/θ-Al<SUB>2</SUB>O<SUB>3</SUB> catalysts with different amount of potassium (0.4, 0.7, 0.95, 1.2 and 1.45wt.%) were prepared by an impregnation method, and their catalytic activity in n-butane dehydrogenation was investigated at 823K, an atmospheric pressure and a GHSV of 18,000mL(g<SUB>cat</SUB>h)<SUP>-1</SUP>. The compositions listed in order of n-C<SUB>4</SUB><SUP>=</SUP> yields at 823K were as follows: K<SUB>0.95</SUB>(PtSn)<SUB>1.5</SUB>>(PtSn)<SUB>1.5</SUB>>K<SUB>0.4</SUB>(PtSn)<SUB>1.5</SUB>>K<SUB>0.7</SUB>(PtSn)<SUB>1.5</SUB>>K<SUB>1.2</SUB>(PtSn)<SUB>1.5</SUB>>K<SUB>1.45</SUB>(PtSn)<SUB>1.5</SUB>>K<SUB>0.9</SUB>(Pt)<SUB>1.5</SUB>. The K<SUB>0.9</SUB>(Pt)<SUB>1.5</SUB> and K<SUB>0.95</SUB>(Sn)<SUB>1.5</SUB> catalyst severely deactivated in n-butane dehydrogenation. The (PtSn)<SUB>1.5</SUB> (without K) catalyst showed the highest n-butane conversion, while K<SUB>0.95</SUB>(PtSn)<SUB>1.5</SUB> did the highest n-C<SUB>4</SUB><SUP>=</SUP> yield. The small amount of potassium on bimetallic PtSn/θ-Al<SUB>2</SUB>O<SUB>3</SUB> catalyst improved n-C<SUB>4</SUB><SUP>=</SUP> selectivity, but slightly decreased n-butane conversion, resulting in the increase of n-C<SUB>4</SUB><SUP>=</SUP> yield. The effect of potassium was caused by blocking the acid sites of Pt catalyst. The TPR and HAADF STEM-EDS study suggested the reduction procedure of the Pt, Sn and K species. However, the higher loaded potassium (1.2 and 1.45wt.%) doped (PtSn)<SUB>1.5</SUB> catalysts were rather highly deactivated because the sizes of Pt particles were increased by weakening the interaction between Pt and Sn. The n-C<SUB>4</SUB><SUP>=</SUP> selectivity of the (PtSn)<SUB>1.5</SUB> catalyst increased with respect to the reaction, while that of the potassium doped catalysts maintained the high n-C<SUB>4</SUB><SUP>=</SUP> selectivity from the beginning of the reaction. Also, different alkali metals (Ca, Na and Li) were tested for the comparison with K. The potassium doped catalyst showed the highest n-C<SUB>4</SUB><SUP>=</SUP> yield among the other alkali metals for n-butane dehydrogenation.
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Jung, K.W.,Cho, S.K.,Yun, Y.M.,Shin, H.S.,Kim, D.H. Pergamon Press ; Elsevier Science Ltd 2013 International journal of hydrogen energy Vol.38 No.22
Application of an up-flow anaerobic sludge blanket (UASB) reactor to dark fermentative H<SUB>2</SUB> production greatly improves H<SUB>2</SUB> productivity due to the maintenance of high biomass concentration. However, a long start-up HRT and start-up period are required to develop the H<SUB>2</SUB>-producing granules (HPGs) and to avoid washing out the suspended sludge at the start of the process. In the present work, a novel strategy to rapidly form HPGs was developed in UASB reactor. To induce highly active mass transfer in the UASB reactor, a high recirculation rate (15 times the influent) was adopted over 10 days, then recirculation was stopped. As the operation progressed, self-flocculation took place and HPGs developed after 90 h of operation. A stable production of H<SUB>2</SUB> was observed after 20 days of operation. The thickness of the HPGs layer in the sole UASB reactor increased progressively, and consequently the average HPG diameter and concentration were 1.86 mm (0.1-3.9 mm) and 52 g/L, respectively, after 60 days of operation. These findings seem to suggest that high-rate recirculation plays a crucial role in accelerating the formation of HPGs in such UASB reactors through high up-flow velocity, providing active mass transfer.
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Jung, K.W.,Moon, C.,Cho, S.K.,Kim, S.H.,Shin, H.S.,Kim, D.H. Elsevier Applied Science 2013 Bioresource technology Vol.139 No.-
In this study, a two-stage system converting organic solid waste (food waste+sewage sludge) to H<SUB>2</SUB> and CH<SUB>4</SUB> was operated. In the first stage of dark fermentative hydrogen production (DFHP), a recently proposed method that does not require external inoculum, was applied. In the second stage, anaerobic sequencing batch reactor (ASBR) and an up-flow anaerobic sludge blanket reactor (UASBr) were followed to treat H<SUB>2</SUB> fermenter effluent. (H<SUB>2</SUB>+CH<SUB>4</SUB>-ASBR) system showed better performance in terms of total biogas conversion (78.6%), while higher biogas production rate (2.03L H<SUB>2</SUB>/L<SUB>system</SUB>/d, 1.96L CH<SUB>4</SUB>/L<SUB>system</SUB>/d) was achieved in (H<SUB>2</SUB>+CH<SUB>4</SUB>-UASBr) system. To reduce the alkali addition requirement in DFHP process, CH<SUB>4</SUB> fermenter effluent was tested as a diluting water. Both the ASBR and UASBr effluent was effective to keep the pH above 6 without CH<SUB>4</SUB> production. In case of using ASBR effluent, H<SUB>2</SUB> production dropped by 15%, but alkali addition requirement was reduced by 50%.
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Jung, K.W.,Kim, D.H.,Kim, H.W.,Shin, H.S. Pergamon Press ; Elsevier Science Ltd 2011 International journal of hydrogen energy Vol.36 No.16
In the present work, a combined (acid + thermal) pretreatment was applied for the enhanced fermentative H<SUB>2</SUB> production (FHP) from Laminaria japonica. Various pretreatment conditions including HCl concentrations, heating temperatures, and reaction times were optimized via response surface methodology (RSM) with a Box-Behnken design (BBD). Through regression analysis, it was found that H<SUB>2</SUB> yield was well fitted by a quadratic polynomial equation (R<SUP>2</SUP> = 0.97), and the HCl concentration was the most significant factor influencing FHP. The desirable pretreatment conditions found were HCl concentration of 4.8%, temperature of 93 <SUP>o</SUP>C, and reaction time of 23 min, under which H<SUB>2</SUB> yield reached to 159.6 mL H<SUB>2</SUB>/g dry cell weight (dcw). The main organic acids produced were acetic and butyric acids that related closely with H<SUB>2</SUB> production. The concentration of hydroxymethylfurfural (HMF), a byproduct formed during the pretreatment process, showed an inverse relationship with H<SUB>2</SUB> yield, indicating that pretreatment conditions for the H<SUB>2</SUB> production from L. japonica were successfully optimized, by increasing the hydrolysis rate of the feedstock and also reducing the formation of HMF.
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Kang, H.M.,Lee, E.K.,Song, B.M.,Heo, G.B.,Jung, J.,Jang, I.,Bae, Y.C.,Jung, S.C.,Lee, Y.J. Elsevier Scientific Pub. Co 2017 Veterinary microbiology Vol.198 No.-
<P>A highly pathogenic avian influenza (HPAI) H5N8 virus was first detected in poultry and wild birds in South Korea in January 2014. Here, we determined the pathogenicity and transmissibility of three different clades of 1-15 viruses in mandarin ducks to examine the potential for wild bird infection. H5N8 (Glade 2.3.4.4) replicated more efficiently in the upper and lower respiratory tract of mandarin ducks than two previously identified H5N1 virus clades (clades 2.2 and 2.3.2.1). However, none of the mandarin ducks infected with H5N8 and H5N1 viruses showed severe clinical signs or mortality, and gross lesions were only observed in a few tissues. Viral replication and shedding were greater in H5N8-infected ducks than in H5N1-infected ducks. Recovery of all viruses from control duck in contact with infected ducks indicated that the highly pathogenic H5 viruses spread horizontally through contact. Taken together, these results suggest that H5N8 viruses spread efficiently in mandarin ducks. Further studies of pathogenicity in wild birds are required to examine possible long-distance dissemination via migration routes. (C) 2016 Elsevier B.V. All rights reserved.</P>
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Kim, B.S.,Jeong, C.S.,Kim, J.M.,Park, S.B.,Park, S.H.,Jeon, J.K.,Jung, S.C.,Kim, S.C.,Park, Y.K. Elsevier Science Publishers 2016 CATALYSIS TODAY - Vol.265 No.-
<P>H-V-MCM-41 catalysts containing 5, 10, and 30 wt% of vanadium were synthesized and applied to the ex situ catalytic pyrolysis (CP) of three polymeric components of lignocellulosic biomass for the first time. Characterization of the catalysts was performed using N-2 adsorption-desorption, XRD, FT-IR, and NH3-TPD. The results of XRD analysis showed that 5 wt% and 10 wt% H-V-MCM-41 catalysts maintained the mesoporous structure, whereas the mesoporous structure was destroyed in 30 wt% H-V-MCM-41 with considerable amount of small V2O5 crystalline outside the framework. NH3-TPD showed that H-V-MCM-41 has mostly weak acid sites and that 10 wt% H-V-MCM-41 had the largest quantity of acid sites due to framework vanadium. In the case of CP of cellulose using Py-GC/MS, 10 wt% H-V-MCM-41 showed the highest catalytic activity for the production of valuable furanic compounds such as furfural because of the enhanced deoxygenation over the acid sites formed on framework vanadium. In the case of CP of xylan as well, 10 wt% H-V-MCM-41 led to the largest yield of mono-aromatics. The production of acetic acid was also promoted by H-V-MCM-41 catalysts. The CP of lignin over H-V-MCM-41 catalysts promoted substantially the production of important feedstock chemicals for the petrochemical industry: phenolics and mono-aromatics. (C) 2015 Elsevier B.V. All rights reserved.</P>
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Eugenol Inhibits K<sup>+</sup> Currents in Trigeminal Ganglion Neurons
Li, H. Y.,Park, C.-K.,Jung, S. J.,Choi, S.-Y.,Lee, S. J.,Park, K.,Kim, J. S.,Oh, S. B. SAGE Publications 2007 Journal of dental research Vol.86 No.9
<P>Eugenol, a natural capsaicin congener, is widely used in dentistry. Eugenol inhibits voltage-activated Na<SUP>+</SUP> and Ca<SUP>2+</SUP> channels in a transient receptor potential vanilloid 1 (TRPV1)-independent manner. We hypothesized that eugenol also inhibits voltage-gated K<SUP>+</SUP> currents, and investigated this in rat trigeminal ganglion neurons and in a heterologous system using whole-cell patch clamping. Eugenol inhibited voltage-gated K<SUP>+</SUP> currents, and the inhibitory effects of eugenol were observed in both capsaicin-sensitive and capsaicin-insensitive neurons. Pre-treatment with capsazepine, a well-known antagonist of TRPV1, failed to block the inhibitory effects of eugenol on K<SUP>+</SUP> currents, suggesting no involvement of TRPV1. Eugenol inhibited human Kv1.5 currents stably expressed in <I>Ltk</I><SUP>−</SUP> cells, where TRPV1 is not endogenously expressed. We conclude that eugenol inhibits voltage-gated K<SUP>+</SUP> currents in a TRPV1-independent manner. The inhibition of voltage-gated K<SUP>+</SUP> currents is likely to contribute to the irritable action of eugenol. Abbreviations: human Kv1.5 channel, hKv1.5; transient receptor potential vanilloid 1, TRPV1.</P>
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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>
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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⋯OC−, −N−CO⋯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>
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