• Journal of the Korean Wood Science and Technology
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• v.47 no.3
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• pp.344-359
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• 2019

Effects of various types of zeolite on the catalytic performance of hydrodeoxygenation (HDO) of bio-oil obtained from waste larch wood pyrolysis were investigated herein. Bifunctional catalysts were prepared via wet impregnation. The catalysts were characterized through XRD, BET, and SEM. Experimental results demonstrated that HDO enhanced the fuel properties of waste wood bio-oil, such as higher heating values (HHV) (20.4-28.3 MJ/kg) than bio-oil (13.7 MJ/kg). Water content (from 19.3 in bio-oil to 3.1-16.6 wt% in heavy oils), the total acid number (from 150 in bio-oil to 28-77 mg KOH/g oil in heavy oils), and viscosity (from 103 in bio-oil to $40-69mm^2/s$ in heavy oils) also improved post HDO. In our experiments, depending on the zeolite support, NiFe/HBeta exhibited a high Si/Al ratio of 38 with a high specific surface area ($545.1m^2/g$), and, based on the yield of heavy oil (18.3-18.9 wt%) and HHV (22.4-25.2 MJ/kg), its performance was not significantly affected by temperature and solvent concentration variations. In contrast, NiFe/zeolite Y, which had a low Si/Al ratio of 5.2, exhibited the highest improved quality for heavy oil at high temperature, with an HHV of 28.3 MJ/kg at $350^{\circ}C$ with 25 wt% of solvent.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.435-442
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• 2021

Mn-added Barium hexaaluminates were manufactured by homogeneous precipitation method using Urea. The effects of water wash and dry temperature were analyzed by thermal weight analysis, X-ray diffraction analysis, and scanning electron microscopy. Catalysts that went through the filtration step only produced pure hexaaluminate images compared to those that went through the water wash step. During the drying process, it seems that the remaining urea helps dehydration of the precursor and affects the phase shift of gibbsite to boehmite, which is easy to convert to pure hexaaluminate. The catalyst WO200 gave the best performance in the methane combustion reaction, and NOx was not emitted in the reaction for all catalysts. Hexaaluminates were found to affect reducing the highest CO emissions.

• Molecules and Cells
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• v.44 no.2
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• pp.101-115
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• 2021

The INO80 chromatin remodeling complex has roles in many essential cellular processes, including DNA replication. However, the mechanisms that regulate INO80 in these processes remain largely unknown. We previously reported that the stability of Ino80, the catalytic ATPase subunit of INO80, is regulated by the ubiquitin proteasome system and that BRCA1-associated protein-1 (BAP1), a nuclear deubiquitinase with tumor suppressor activity, stabilizes Ino80 via deubiquitination and promotes replication fork progression. However, the E3 ubiquitin ligase that targets Ino80 for proteasomal degradation was unknown. Here, we identified the C-terminus of Hsp70-interacting protein (CHIP), the E3 ubiquitin ligase that functions in cooperation with Hsp70, as an Ino80-interacting protein. CHIP polyubiquitinates Ino80 in a manner dependent on Hsp70. Contrary to our expectation that CHIP degrades Ino80, CHIP instead stabilizes Ino80 by extending its half-life. The data suggest that CHIP stabilizes Ino80 by inhibiting degradative ubiquitination. We also show that CHIP works together with BAP1 to enhance the stabilization of Ino80, leading to its chromatin binding. Interestingly, both depletion and overexpression of CHIP compromise replication fork progression with little effect on fork stalling, as similarly observed for BAP1 and Ino80, indicating that an optimal cellular level of Ino80 is important for replication fork speed but not for replication stress suppression. This work therefore idenitifes CHIP as an E3 ubiquitin ligase that stabilizes Ino80 via nondegradative ubiquitination and suggests that CHIP and BAP1 act in concert to regulate Ino80 ubiquitination to fine-tune its stability for efficient DNA replication.

• Analytical Science and Technology
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• v.19 no.5
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• pp.422-432
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• 2006

The volatile organic compounds(VOCs) have been recognized as a major contributor to air pollution. The catalytic oxidation is one of the most important processes for VOCs destruction due to getting high efficiency at low temperature. In this study, monometallic Pt and bimetallic Pt-Ru, Pt-Ir were supported to ${\gamma}-Al_2O_3$. Xylene, toluene and MEK were used as reactants. The monometallic or bimetallic catalysts were prepared by the excess wetness impregnation method and were characterized by XRD, XPS, TEM and BET analysis. As a result, Pt-Ru, Pt-Ir bimetallic catalysts showed higher conversion than Pt monometallic catalyst. Pt-Ir bimetallic catalyst showed the highest conversion on the ${\gamma}-Al_2O_3$ support. In the VOCs oxidation, Pt-Ru, Pt-Ir bimetallic catalyst had multipoint active sites, so it improved the range of Pt metal state. Therefore, bimetallic catalysts showed higher conversion of VOCs than monometallic ones. In this study, the use of small amount of Ru, Ir to Pt promoted oxidation conversion of VOCs.

• Korean Journal of Materials Research
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• v.33 no.11
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• pp.447-457
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• 2023

Single-atom Pd clusters anchored on t-BaTiO₃ material was synthesized using hydrothermal and ultrasonic methods for the effective piezoelectric catalytic degradation of pollutants using vibration energy. XRD patterns of BaTiO₃ loaded with monoatomic Pd were obtained before and after calcining, and showed typical cubic-phase BTO. TEM and HAADF-STEM images indicated single-atom Pd clusters were successfully introduced into the BaTiO₃. The piezoelectric current density of the prepared Pd-BaTiO₃ binary composite was significantly higher than that of the pristine BaTiO₃. Under mechanical vibration, the nanomaterial exhibited a tetracycline decomposition rate of ~95 % within 7 h, which is much higher than the degradation rate of 56.7 % observed with pure BaTiO₃. Many of the piezo-induced electrons escaped to the Pd-doped BaTiO₃ interface because of Pd's excellent conductivity. Single-atom Pd clusters help promote the separation of the piezo-induced electrons, thereby achieving synergistic catalysis. This work demonstrates the feasibility of combining ultrasonic technology with the piezoelectric effect and provides a promising strategy for the development of ultrasonic and piezoelectric materials.

• Biomolecules & Therapeutics
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• v.32 no.2
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• pp.214-223
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• 2024

Metabolic abnormalities in the liver are closely associated with diverse metabolic diseases such as non-alcoholic fatty liver disease, type 2 diabetes, and obesity. The aim of this study was to evaluate the ameliorating effect of robinetin (RBN) on the significant pathogenic features of metabolic failure in the liver and to identify the underlying molecular mechanism. RBN significantly decreased triglyceride (TG) accumulation by downregulating lipogenesis-related transcription factors in AML-12 murine hepatocyte cell line. In addition, mice fed with Western diet (WD) containing 0.025% or 0.05% RBN showed reduced liver mass and lipid droplet size, as well as improved plasma insulin levels and homeostatic model assessment of insulin resistance (HOMA-IR) values. CD38 was identified as a target of RBN using the BioAssay database, and its expression was increased in OPA-treated AML-12 cells and liver tissues of WD-fed mice. Furthermore, RBN elicited these effects through its anti-histone acetyltransferase (HAT) activity. Computational simulation revealed that RBN can dock into the HAT domain pocket of p300, a histone acetyltransferase, which leads to the abrogation of its catalytic activity. Additionally, knock-down of p300 using siRNA reduced CD38 expression. The chromatin immunoprecipitation (ChIP) assay showed that p300 occupancy on the promoter region of CD38 was significantly decreased, and H3K9 acetylation levels were diminished in lipid-accumulated AML-12 cells treated with RBN. RBN improves the pathogenic features of metabolic failure by suppressing the p300-CD38 axis through its anti-HAT activity, which suggests that RBN can be used as a new phytoceutical candidate for preventing or improving this condition.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2263-2273
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• 2000

Catalytic wet air oxidation of acetic acid over Mn-Ce based catalysts deposited on various supports ($SiO_2$, $TiO_2$, $ZrO_2$), $ZrSiO_4$, $ZrO_2(10wt%)/TiO_2$) have been carried out in high pressure microreactors. Also, promotional effects by small addition(O.5~1.0 wt%) of p-type semiconductors (CoO, $Ag_2O$, SnO) have been investigated. From the screening tests for initial activity ranking, both Mn(2.8)-Ce(7.2 wt%) and Ru(O.4)Mn(2.7)-Ce(6.9 wt%) supported on $TiO_2$ were selected as the promising reference candidates. In $Mn-Ce/TiO_2$ reference catalyst, addition of small amount of each p-type semiconductor (Co, Sn and Ag) resulted in activity promotional effect and the degree of the increase was in the following order: Co> Ag > Sn. Especially, $Mn-Ce/TiO_2$ promoted with 0.5 wt% Co gave the 2.6 folds activity increase compared to the reference case attributing to the surface area increase as well as synergy effect. In $Ru-Mn-Ce/TiO_2$ reference catalyst, only Co(1.0 wt%) promoted case showed a little reaction rate increase.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.609-617
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• 2000

This study is aimed at investigating an effect of HCl gas on selective reduction of NOx over a CuHM and $V_2O_5-WO_3/TiO_2$ catalyst. SCR process is the most effective method to remove NOx, but catalyst can be deactivated by the acidic gas such as HCl gas which is also included in flue gas from the incinerator. In dry condition of flue gas, the CuHM catalyst treated by HCl gas has shown higher NO removal activity than the fresh catalyst. The activity of the catalyst can be restored by treating at $500^{\circ}C$. On the contrary. $V_2O_5-WO_3/TiO_2$ catalyst is obviously deactivated by HCl and the deactivation increases in proportion to the concentration of HCl gas. The deactivated catalyst is not restored to it's original activity by heat treatment for regeneration. In wet flue gas stream, the CuHM catalyst has shown lower activity than fresh catalyst and $V_2O_5-WO_3/TiO_2$ catalyst was severely deactivated by HCl treatment. The activity loss of catalysts are mainly due to the decrease of Br$\ddot{o}$nsted acid site on the catalyst surface by $NH_3$ TPD. The change of BET surface area of CuHM catalyst after the reaction isn't observed but $V_2O_5-WO_3/TiO_2$ catalyst is observed. The amount of $Cu^{{+}{+}}$ and $V_2O_5$ is decreased after the reaction. From these results, it is expected that CuHM catalyst should be better than $V_2O_5-WO_3/TiO_2$ catalyst for its application to the incineration of flue gas.

• Journal of the Korean Chemical Society
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• v.37 no.2
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• pp.228-236
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• 1993

The effect of ferric ion on the reaction of CH_3$MgI with benzylbromide was investigated by determining the product ratio between cross-coupling product, ethylbenzene (A) and homocoupling product, bibenzyl (B) in the presence of ferric ion. When CH_3$MgI prepared with pure magnesium was used, the ratio of A to B was 22 to 78 and with reagent grade magnesium, the ratio became 33 to 67 indicating that metallic impurities in magnesium affect the reaction mechanism to lead less homocoupling product, B. The ratio changes became significant when ferric chloride was added in the reaction mixture in catalytic amounts and the ratio of A to B reached to 80 to 20 at maximum. The reaction in the presence of ferric ion seems to follow mainly an ionic mechanism which involves iron-benzyl bromide ${\pi}$-complex formation. The complex formation is expected to be able to enhance ionic attack of CH_3$MgI on benzyl carbon to give more A.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.1
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• pp.57-64
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• 2020

The water-gas shift reaction for the compact reformer was carried out at a gas hourly space velocity of 72,152 h^-1 over the Cu-Nb-CeO₂ catalysts prepared by co-precipitation method. In order to investigate the effect of Nb₂O₅ promotion over a Cu-CeO₂ catalyst, the Nb₂O₅ loading amount was systematically changed from 0 to 5 wt.%. Among the prepared catalysts, the Cu-Nb-CeO₂ (1%) catalyst showed the highest catalytic activity (CO conversion=61% at 400℃) as well as 100% CO₂ selectivity. The high activity and stability of Cu-Nb-CeO₂ (1%) catalyst are correlated to high Brunauer-Emmett-Teller surface area, small metallic Cu crystallite size, and enhanced redox property.