1,871 results on '"Soo‐Jin Park"'
Search Results
2. Potential endocrine-disrupting effects of iprodione via estrogen and androgen receptors: evaluation using in vitro assay and an in silico model
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Ji-Yeon Yang, Jeong-Hyun Lim, Soo-Jin Park, Youmi Jo, Si Young Yang, Min-Kyoung Paik, and So-Hye Hong
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Pesticides ,Iprodione ,Endocrine-disrupting chemical ,Estrogen receptor ,Androgen receptor ,Agriculture (General) ,S1-972 ,Chemistry ,QD1-999 - Abstract
Abstract This study was conducted to provide evidence, using in vitro and in silico testing methods, regarding the adverse effects of iprodione, a representative dichlorophenyl dicarboxamide fungicide, on the endocrine system. In the present study, we used the HeLa9903 stably transfected transactivation assay (OECD TG 455), 22Rv1/MMTV_GR‒KO androgen receptor transcriptional activation assay (OECD TG 458), and toxicity prediction using VEGA QSAR. Our results showed that iprodione had no estrogen receptor antagonistic or androgen receptor agonistic effects; however, iprodione was determined to be an estrogen receptor agonist (log PC10 value is less than − 9) and androgen receptor antagonist (log IC30 value is − 4.58) without intrinsic toxicity against the human cell lines used in this study. VEGA QSAR was used to evaluate five substances with structures similar to that of iprodione. Among them, four chemicals were found to have positive androgen receptor and aromatase activities and have been observed to be developmental toxicants. These results suggest that iprodione regulates steroid hormone receptor interactions and is a potential reproductive toxicant.
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- 2024
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3. Advancements in Asymmetric Supercapacitors: From Historical Milestones to Challenges and Future Directions
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Shrikant Vaiju Sadavar, Seul‐Yi Lee, and Soo‐Jin Park
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asymmetric supercapacitors ,basic principles ,categorization ,electrode materials ,industrial applications ,Science - Abstract
Abstract Numerous challenges, like the uninterrupted supply of electricity, stable and reliable power, and energy storage during non‐operational hours, arise across various industries due to the absence of advanced energy storage technologies. With the continual technological advancements in portable electronics, green energy, and transportation, there are inherent limitations in their innovative production. Thus, ongoing research is focused on pursuing sustainable energy storage technologies. An emerging solution lies in the development of asymmetric supercapacitors (ASCs), which offer the potential to extend their operational voltage limit beyond the thermodynamic breakdown voltage range of electrolytes. This is achieved by employing two distinct electrode materials, presenting an effective solution to the energy storage limitations faced by ASCs. The current review concentrates on the progression of working materials to develop authentic pseudocapacitive energy storage systems (ESS). Also, evaluates their ability to exceed energy storage constraints. It provides insights into fundamental energy storage mechanisms, performance evaluation methodologies, and recent advancements in electrode material strategies. The review approaches developing high‐performance electrode materials and achieving efficient ASC types. It delves into critical aspects for enhancing the energy density of ASCs, presenting debates and prospects, thereby offering a comprehensive understanding and design principles for next‐generation ASCs in diverse applications.
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- 2024
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4. Functionalized MXene ink enables environmentally stable printed electronics
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Tae Yun Ko, Heqing Ye, G. Murali, Seul-Yi Lee, Young Ho Park, Jihoon Lee, Juyun Lee, Dong-Jin Yun, Yury Gogotsi, Seon Joon Kim, Se Hyun Kim, Yong Jin Jeong, Soo-Jin Park, and Insik In
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Science - Abstract
Abstract Establishing dependable, cost-effective electrical connections is vital for enhancing device performance and shrinking electronic circuits. MXenes, combining excellent electrical conductivity, high breakdown voltage, solution processability, and two-dimensional morphology, are promising candidates for contacts in microelectronics. However, their hydrophilic surfaces, which enable spontaneous environmental degradation and poor dispersion stability in organic solvents, have restricted certain electronic applications. Herein, electrohydrodynamic printing technique is used to fabricate fully solution-processed thin-film transistors with alkylated 3,4-dihydroxy-L-phenylalanine functionalized Ti3C2T x (AD-MXene) as source, drain, and gate electrodes. The AD-MXene has excellent dispersion stability in ethanol, which is required for electrohydrodynamic printing, and maintains high electrical conductivity. It outperformed conventional vacuum-deposited Au and Al electrodes, providing thin-film transistors with good environmental stability due to its hydrophobicity. Further, thin-film transistors are integrated into logic gates and one-transistor-one-memory cells. This work, unveiling the ligand-functionalized MXenes’ potential in printed electrical contacts, promotes environmentally robust MXene-based electronics (MXetronics).
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- 2024
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5. Role of Copper Nanoparticles in the Thermal and Mechanical Properties of Expanded Graphite-Reinforced Epoxy Hybrids
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Hai-Long Cheng, Na Chu, Fan-Long Jin, and Soo-Jin Park
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Chemistry ,QD1-999 - Published
- 2024
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6. A Review of Rechargeable Zinc–Air Batteries: Recent Progress and Future Perspectives
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Ghazanfar Nazir, Adeela Rehman, Jong-Hoon Lee, Choong-Hee Kim, Jagadis Gautam, Kwang Heo, Sajjad Hussain, Muhammad Ikram, Abeer A. AlObaid, Seul-Yi Lee, and Soo-Jin Park
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Zinc–air batteries ,Energy storage ,Affordability ,Reversibility ,Technology - Abstract
Highlights Recent progress in Zn–air batteries is critically reviewed. Current challenges of rechargeable Zn–air batteries are highlighted. Strategies for the advancement of the anode, electrolyte, and oxygen catalyst are discussed. Future research directions are provided to design commercial Zn–air batteries.
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- 2024
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7. Enhanced Electrical Properties and Impact Strength of Phenolic Formaldehyde Resin Using Silanized Graphene and Ionic Liquid
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Yan-Chun Li, Seul-Yi Lee, Hong Wang, Fan-Long Jin, and Soo-Jin Park
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Chemistry ,QD1-999 - Published
- 2023
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8. Review of Wear and Mechanical Characteristics of Al-Si Alloy Matrix Composites Reinforced with Natural Minerals
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Varun Singhal, Daksh Shelly, Atul Babbar, Seul-Yi Lee, and Soo-Jin Park
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aluminium metal matrix composites ,stir casting ,natural reinforcements ,mechanical properties ,wear resistance ,Science - Abstract
Al-Si alloys are vital in the aerospace and automotive industries due to their high strength-to-weight ratio, excellent ductility, and superior corrosion resistance. These properties, along with good thermal conductivity, low thermal expansion, and enhanced wear resistance due to silicon, make them ideal for lightweight, high-performance components like engine parts exposed to harsh conditions and thermal cycling. In recent years, the development of aluminium metal matrix composites using Al-Si alloys as the base material has gathered significant attention. These composites are engineered by integrating various reinforcing particles into the aluminium matrix, which results in remarkable improvements in the wear resistance, hardness, and overall mechanical performance of the material. The stir casting process, a well-established and cost-effective method, is frequently employed to ensure a uniform distribution of these reinforcing particles within the matrix. This review delves into the influence of different types of reinforcing particles on the properties of Al-Si alloy-based AMCs. The incorporation of these reinforcements has been shown to significantly enhance wear resistance, reduce friction, and improve the overall strength and toughness of the composites, making them ideal candidates for high-performance applications in the automotive and aerospace sectors. Moreover, this review highlights the challenges associated with the fabrication of these composites, such as achieving a homogeneous particle distribution and minimizing porosity. It also discusses the latest advancements in processing techniques aimed at overcoming these challenges. Additionally, this review addresses the potential environmental and economic benefits of using natural reinforcements, which not only reduce material costs but also contribute to sustainable manufacturing practices.
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- 2024
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9. Resource Adequacy and Integration of Renewables in Light of US, EU, and Pakistan’s Evolving Power Sector
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Muhammad Sadam Hussain, Kangwook Cho, and Soo-jin Park
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resource adequacy ,capacity accreditation ,competitive trading bilateral contract market (CTBCM) ,renewable energy ,demand response ,battery storage ,Technology - Abstract
This study investigates resource adequacy and renewable energy integration in the United States, European Union, and Pakistan amid global energy market liberalization and greenhouse gas reduction efforts. It explores how these regions are adapting to the surge in renewable sources like wind and solar, which, despite their financial and environmental benefits, challenge resource adequacy and the economic viability of traditional energy sources. In the US and EU, significant improvements have been introduced in wholesale electricity markets and capacity accreditation mechanisms, which enhanced the large-scale deployment of renewables. This shift has prompted a reevaluation of resource adequacy, leading to the increased deployment of battery storage and demand response. Presently, gas-based generation is largely upholding resource adequacy; however, future trends indicate a move towards greater consumer participation, energy efficiency, and utility-scale storage, with a decline in fossil fuel use. Pakistan aims to adopt a liberalized market structure by balancing competitive markets with legacy contracts. Public pressure is driving a shift from costly fossil-based generation to renewables. Similarly, a trend in the rise of behind-the-meter solar generation can be witnessed. In the future, Pakistan may also experience resource adequacy challenges. It will likely need to implement battery storage, demand response, and modern capacity accreditation tools, by drawing lessons from developed markets.
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- 2024
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10. Recent advances in polymeric and small molecule donor materials for Y6 based organic solar cells
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Vivek Vishal Sharma, Ayuningtias Landep, Seul-Yi Lee, Soo-Jin Park, Yun-Hi Kim, and Gi-Hwan Kim
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Organic solar cells ,Small molecules ,Polymer ,PM6 ,Y6 ,Donor ,Energy industries. Energy policy. Fuel trade ,HD9502-9502.5 ,Renewable energy sources ,TJ807-830 - Abstract
Organic solar cells (OSCs) have emerged as a promising alternative to traditional inorganic solar cells due to their environmentally friendly nature and inexhaustible solar energy potential. Recent advancements in non-fullerene acceptors (NFAs), particularly the novel NFA Y6 with an acceptor-donor-acceptor (A-D-A) type structure, have significantly boosted the power conversion efficiency (PCE) of OSCs, surpassing 18%. The Y6-based OSCs have demonstrated high open circuit voltage (VOC), short circuit current density (JSC), and fill factor (FF), marking an important milestone in OSC progress. This review focusses exclusively on Y6-based OSCs and their potential to revolutionize the field. It discusses the design strategies and structure-performance relationship for efficient donor materials, with emphasis on polymeric and small molecule donors (SMD). The review highlights the challenges and opportunities in achieving further efficiency improvements beyond 20% for polymeric donors and 16% for small molecules. By leveraging the unique properties of Y6-type acceptors, such as stronger light absorption and tunable energy levels, researchers have achieved remarkable progress in OSC performance. The rational molecular optimization of polymer donors, complementing Y6's narrow bandgap with wide bandgap polymers, and achieving sufficient driving force for charge separation through lower highest-occupied molecular orbital (HOMO) levels, have contributed to the significant PCE enhancements. While Y6-based OSCs have demonstrated great potential, this review also discusses the use of SMD as an increasingly attractive option, offering advantages such as convenient material synthesis and improved crystallinity for higher VOC. Overall, this comprehensive review presents the most advanced developments and insights, paving the way for further advancements in Y6-based OSC technology.
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- 2024
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11. A Review on Interface Engineering of MXenes for Perovskite Solar Cells
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Srikanta Palei, G. Murali, Choong-Hee Kim, Insik In, Seul-Yi Lee, and Soo-Jin Park
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MXenes ,Perovskite solar cells ,Additives ,Interfacial layer ,Electrodes ,Technology - Abstract
Highlights This review discusses the roles of MXenes in different positions/layers in perovskite solar cells. The issues in different layers/interfaces and their addressal with the incorporations of MXenes in perovskite solar cells are elaborately discussed.
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- 2023
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12. Simulating of effective conductivity for graphene–polymer nanocomposites
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Mostafa Vatani, Yasser Zare, Nima Gharib, Kyong Yop Rhee, and Soo-Jin Park
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Medicine ,Science - Abstract
Abstract The efficient conductivity of graphene-polymer systems is expressed supposing graphene, tunneling and interphase components. The volume shares and inherent resistances of the mentioned components are used to define the efficient conductivity. Besides, the percolation start and the share of graphene and interphase pieces in the nets are formulated by simple equations. Also, the resistances of tunneling and interphase parts are correlated to graphene conductivity and their specifications. Suitable arrangements among experimented data and model’s estimates as well as the proper trends between efficient conductivity and model’s parameters validate the correctness of the novel model. The calculations disclose that the efficient conductivity improves by low percolation level, dense interphase, short tunnel, large tunneling pieces and poor polymer tunnel resistivity. Furthermore, only the tunneling resistance can govern the electron transportation between nanosheets and efficient conductivity, while the big amounts of graphene and interphase conductivity cannot play a role in the efficient conductivity.
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- 2023
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13. Carbon‐Based Radar Absorbing Materials toward Stealth Technologies
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Seong‐Hwang Kim, Seul‐Yi Lee, Yali Zhang, Soo‐Jin Park, and Junwei Gu
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carbon materials ,radar‐absorbing materials (rams) ,stealth technology ,Science - Abstract
Abstract Stealth technology is used to enhance the survival of military equipment in the field of military surveillance, as it utilizes a combination of techniques to render itself undetectable by enemy radar systems. Radar absorbing materials (RAMs) are specialized materials used to reduce the reflection (or absorption) of radar signals to provide stealth capability, which is a core component of passive countermeasures in military applications. The properties of RAMs can be optimized by adjusting their composition, microstructure, and surface geometry. Carbon‐based materials present a promising approach for the fabrication of ultrathin, versatile, and high‐performance RAMs due to their large specific surface area, lightweight, excellent dielectric properties, high electrical conductivity, and stability under harsh conditions. This review begins with a brief history of stealth technology and an introduction to electromagnetic waves, radar systems, and radar absorbing materials. This is followed by a discussion of recent research progress in carbon‐based RAMs, including carbon blacks, carbon fibers, carbon nanotubes, graphite, graphene, and MXene, along with an in‐depth examination of the principles and strategies on electromagnetic attenuation characteristics. Hope this review will offer fresh perspectives on the design and fabrication of carbon‐based RAMs, thereby fostering a deeper fundamental understanding and promoting practical applications.
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- 2023
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14. Progressing of a power model for electrical conductivity of graphene-based composites
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Yasser Zare, Kyong Yop Rhee, and Soo-Jin Park
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Medicine ,Science - Abstract
Abstract This work presents a power equation for the conductivity of graphene-based polymer composites by the tunneling length, interphase deepness and filler size. The impressions of these factors on the effective concentration and percolation beginning of graphene nano-sheets in nanocomposites are also expressed. The developed equations for percolation beginning and conductivity are examined by the experimented data of some examples, which can guesstimate the interphase depth, tunneling size and percolation exponent. Besides, the impacts of numerous factors on the percolation beginning and conductivity are designed. The developed equation for percolation beginning shows the formation of thick interphase and large tunnels in the reported samples. So, disregarding of tunneling and interphase spaces in polymer graphene nanocomposites overpredicts the percolation beginning. Additionally, the developed model presents the acceptable calculations for the conductivity of samples. Among the mentioned parameters, the concentration and graphene conductivity in addition to the interphase depth induce the strongest effects on the conductivity of composites.
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- 2023
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15. Highly Flexible Fabrics/Epoxy Composites with Hybrid Carbon Nanofillers for Absorption-Dominated Electromagnetic Interference Shielding
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Jong-Hoon Lee, Yoon-Sub Kim, Hea-Jin Ru, Seul-Yi Lee, and Soo-Jin Park
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Conductive polymer composites ,Fracture toughness ,Flexible composites ,Absorption-dominated electromagnetic interference shielding ,Technology - Abstract
Abstract Epoxy-based nanocomposites can be ideal electromagnetic interference (EMI)-shielding materials owing to their lightness, chemical inertness, and mechanical durability. However, poor conductivity and brittleness of the epoxy resin are challenges for fast-growing portable and flexible EMI-shielding applications, such as smart wristband, medical cloth, aerospace, and military equipment. In this study, we explored hybrid nanofillers of single-walled carbon nanotubes (SWCNT)/reduced graphene oxide (rGO) as conductive inks and polyester fabrics (PFs) as a substrate for flexible EMI-shielding composites. The highest electrical conductivity and fracture toughness of the SWCNT/rGO/PF/epoxy composites were 30.2 S m−1 and 38.5 MPa m1/2, which are ~ 270 and 65% enhancement over those of the composites without SWCNTs, respectively. Excellent mechanical durability was demonstrated by stable electrical conductivity retention during 1000 cycles of bending test. An EMI-shielding effectiveness of ~ 41 dB in the X-band frequency of 8.2–12.4 GHz with a thickness of 0.6 mm was obtained with an EM absorption-dominant behavior over a 0.7 absorption coefficient. These results are attributed to the hierarchical architecture of the macroscale PF skeleton and nanoscale SWCNT/rGO networks, leading to superior EMI-shielding performance. We believe that this approach provides highly flexible and robust EMI-shielding composites for next-generation wearable electronic devices.
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- 2022
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16. Daphnetin Alleviates Bleomycin-Induced Pulmonary Fibrosis through Inhibition of Epithelial-to-Mesenchymal Transition and IL-17A
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Soo-Jin Park, Hyung Won Ryu, Ji-Hyeong Kim, Hwa-Jeong Hahn, Hyun-Jae Jang, Sung-Kyun Ko, Sei-Ryang Oh, and Hyun-Jun Lee
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daphnetin ,idiopathic pulmonary fibrosis ,TGF-β ,Th17 ,IL-17A ,Cytology ,QH573-671 - Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic and refractory interstitial lung disease. Although there is no cure for IPF, the development of drugs with improved efficacy in the treatment of IPF is required. Daphnetin, a natural coumarin derivative, has immunosuppressive, anti-inflammatory, and antioxidant activities. However, its antifibrotic effects have not yet been elucidated. In this study, we investigated the antifibrotic effects of daphnetin on pulmonary fibrosis and the associated molecular mechanism. We examined the effects of daphnetin on splenocytes cultured in Th17 conditions, lung epithelial cells, and a mouse model of bleomycin (BLM)-induced pulmonary fibrosis. We identified that daphnetin inhibited IL-17A production in developing Th17 cells. We also found that daphnetin suppressed epithelial-to-mesenchymal transition (EMT) in TGF-β-treated BEAS2B cells through the regulation of AKT phosphorylation. In BLM-treated mice, the oral administration of daphnetin attenuated lung histopathology and improved lung mechanical functions. Our findings clearly demonstrated that daphnetin inhibited IL-17A and EMT both in vitro and in vivo, thereby protecting against BLM-induced pulmonary fibrosis. Taken together, these results suggest that daphnetin has potent therapeutic effects on lung fibrosis by modulating both Th17 differentiation and the TGF-β signaling pathway, and we thus expect daphnetin to be a drug candidate for the treatment of IPF.
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- 2023
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17. Application of an Antioxidant Response Element–Nuclear Factor Erythroid 2 Luciferase Assay for Assessing the Skin Sensitization Potential of Agrochemicals
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Ji-Yeon Yang, Soo-Jin Park, Ji-Young Shin, Jeong-Hyun Lim, Si Young Yang, Geun-Hwan Gil, and So-Hye Hong
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skin sensitization ,agrochemicals ,alternative methods ,antioxidant response element ,nuclear factor erythroid 2 luciferase assay ,adverse outcome pathway ,Chemical technology ,TP1-1185 - Abstract
The skin sensitization potential of agrochemicals can be assessed using laboratory methods such as the keratinocyte activation assay so that their use in regulatory toxicology might replace experimental animal testing. Here, we evaluated the skin sensitization potential of 11 agrochemicals by using an antioxidant response element–nuclear factor erythroid 2 luciferase assay in KeratinoSens and LuSens cells and applying a skin sensitization adverse outcome pathway (AOP). The KeratinoSens and LuSens assays consistently evaluated the skin sensitization potential of 10/11 agrochemicals with reference to animal testing databases. Benomyl, pretilachlor, fluazinam, terbufos, butachlor, and carbosulfan were correctly detected as sensitizers, and glufosinate ammonium, oxiadiazon, tebuconazole, and etofenprox were correctly detected as non-sensitizers. For diazinon, the skin sensitizing potential was positive in the KeratinoSens assay but not in the LuSens assay. These results suggest that the evaluation of in vitro skin sensitization using the AOP mechanism can be applied to assess active agrochemicals.
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- 2023
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18. Surfactant-Capped Silver-Doped Calcium Oxide Nanocomposite: Efficient Sorbents for Rapid Lithium Uptake and Recovery from Aqueous Media
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Urooj Kamran, Hasan Jamal, Md Irfanul Haque Siddiqui, and Soo-Jin Park
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transition metal doping ,lithium ,stabilizer ,nanocomposites ,metal recovery ,adsorption ,Hydraulic engineering ,TC1-978 ,Water supply for domestic and industrial purposes ,TD201-500 - Abstract
The demand for lithium is constantly increasing due to its wide range of uses in an excessive number of industrial applications. Typically, expensive lithium-based chemicals (LiOH, LiCl, LiNO3, etc.) have been used to fabricate adsorbents (i.e., lithium manganese oxide) for lithium ion (Li+) adsorption from aqueous sources. This type of lithium-based adsorbent does not seem to be very effective in recovering Li+ from water from an economic point of view. In this study, an innovative nanocomposite for Li+ adsorption was investigated for the first time, which eliminates the use of lithium-based chemicals for preparation. Here, calcium oxide nanoparticles (CaO-NPs), silver-doped CaO nanoparticles (Ag-CaO-NPs), and surfactant (polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS))-modified Ag-CaO (PVP@Ag-CaO and SDS@Ag-CaO) nanocomposites were designed by the chemical co-precipitation method. The PVP and SDS surfactants acted as stabilizing and capping agents to enhance the Li+ adsorption and recovery performance. The physicochemical properties of the designed samples (morphology, size, surface functionality, and crystallinity) were also investigated. Under optimized pH (10), contact time (8 h), and initial Li+ concentration (2 mg L−1), the highest Li+ adsorption efficiencies recorded by SDS@Ag-CaO and PVP@Ag-CaO were 3.28 mg/g and 2.99 mg/g, respectively. The nature of the Li+ adsorption process was examined by non-linear kinetic and isothermal studies, which revealed that the experimental data were best fit by the pseudo-first-order and Langmuir models. Furthermore, it was observed that the SDS@Ag-CaO nanocomposite exhibited the highest Li+ recovery potential (91%) compared to PVP@Ag-CaO (85%), Ag-CaO NPs (61%), and CaO NPs (43%), which demonstrates their regeneration potential. Therefore, this type of innovative adsorbents can provide new insights for the development of surfactant-capped nanocomposites for enhanced Li+ metal recovery from wastewater.
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- 2023
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19. Determination of Hydrophobic Dispersive Surface Free Energy of Activated Carbon Fibers Measured by Inverse Gas Chromatographic Technique
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Seul-Yi Lee, Yeong-Hun Kim, Roop L. Mahajan, and Soo-Jin Park
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activated carbon fiber ,hydrophobic surface component ,surface free energy ,inverse gas chromatography ,Chemistry ,QD1-999 - Abstract
Activated carbon fibers (ACFs) as one of the most important porous carbon materials are widely used in many applications that involve rapid adsorption and low-pressure loss, including air purification, water treatment, and electrochemical applications. For designing such fibers for the adsorption bed in gas and aqueous phases, in-depth comprehension of the surface components is crucial. However, achieving reliable values remains a major challenge due to the high adsorption affinity of ACFs. To overcome this problem, we propose a novel approach to determine London dispersive components (γSL) of the surface free energy of ACFs by inverse gas chromatography (IGC) technique at an infinite dilution. Our data reveal the γSL values at 298 K for bare carbon fibers (CFs) and the ACFs to be 97 and 260–285 mJ·m−2, respectively, which lie in the regime of secondary bonding of physical adsorption. Our analysis indicates that these are impacted by micropores and defects on the carbon surfaces. Comparing the γSL obtained by the traditional Gray’s method, our method is concluded as the most accurate and reliable value for the hydrophobic dispersive surface component of porous carbonaceous materials. As such, it could serve as a valuable tool in designing interface engineering in adsorption-related applications.
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- 2023
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20. Highly Porous Carbon Aerogels for High-Performance Supercapacitor Electrodes
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Jong-Hoon Lee, Seul-Yi Lee, and Soo-Jin Park
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carbon aerogel ,supercapacitor ,sol–gel polymerization ,electric double-layer capacitors ,physical activation ,Chemistry ,QD1-999 - Abstract
In recent years, porous carbon materials with high specific surface area and porosity have been developed to meet the commercial demands of supercapacitor applications. Carbon aerogels (CAs) with three-dimensional porous networks are promising materials for electrochemical energy storage applications. Physical activation using gaseous reagents provides controllable and eco-friendly processes due to homogeneous gas phase reaction and removal of unnecessary residue, whereas chemical activation produced wastes. In this work, we have prepared porous CAs activated by gaseous carbon dioxide, with efficient collisions between the carbon surface and the activating agent. Prepared CAs display botryoidal shapes resulting from aggregation of spherical carbon particles, whereas activated CAs (ACAs) display hollow space and irregular particles from activation reactions. ACAs have high specific surface areas (2503 m2 g−1) and large total pore volumes (1.604 cm3 g−1), which are key factors for achieving a high electrical double-layer capacitance. The present ACAs achieved a specific gravimetric capacitance of up to 89.1 F g−1 at a current density of 1 A g−1, along with a high capacitance retention of 93.2% after 3000 cycles.
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- 2023
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21. Graphene-Based Electrochemical Biosensors for Breast Cancer Detection
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Ali Mohammadpour-Haratbar, Seyyed Behnam Abdollahi Boraei, Yasser Zare, Kyong Yop Rhee, and Soo-Jin Park
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graphene ,electrochemical biosensors ,breast cancer ,biomarker ,nanoparticles ,Biotechnology ,TP248.13-248.65 - Abstract
Breast cancer (BC) is the most common cancer in women, which is also the second most public cancer worldwide. When detected early, BC can be treated more easily and prevented from spreading beyond the breast. In recent years, various BC biosensor strategies have been studied, including optical, electrical, electrochemical, and mechanical biosensors. In particular, the high sensitivity and short detection time of electrochemical biosensors make them suitable for the recognition of BC biomarkers. Moreover, the sensitivity of the electrochemical biosensor can be increased by incorporating nanomaterials. In this respect, the outstanding mechanical and electrical performances of graphene have led to an increasingly intense study of graphene-based materials for BC electrochemical biosensors. Hence, the present review examines the latest advances in graphene-based electrochemical biosensors for BC biosensing. For each biosensor, the detection limit (LOD), linear range (LR), and diagnosis technique are analyzed. This is followed by a discussion of the prospects and current challenges, along with potential strategies for enhancing the performance of electrochemical biosensors.
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- 2023
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22. Theophylline Attenuates BLM-Induced Pulmonary Fibrosis by Inhibiting Th17 Differentiation
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Soo-Jin Park, Hwa-Jeong Hahn, Sei-Ryang Oh, and Hyun-Jun Lee
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theophylline ,pulmonary fibrosis ,Th17 ,TGF-β ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic and refractory interstitial lung disease. Although there are two approved drugs for IPF, they were not able to completely cure the disease. Therefore, the development of new drugs is required for the effective treatment of IPF. In this study, we investigated the effect of theophylline, which has long been used for the treatment of asthma, on pulmonary fibrosis. The administration of theophylline attenuated the fibrotic changes of lung tissues and improved mechanical pulmonary functions in bleomycin (BLM)-induced pulmonary fibrosis. Theophylline treatment suppressed IL-17 production through inhibiting cytokines controlling Th17 differentiation; TGF-β, IL-6, IL-1β, and IL-23. The inhibition of IL-6 and IL-1β by theophylline is mediated by suppressing BLM-induced ROS production and NF-κB activation in epithelial cells. We further demonstrated that theophylline inhibited TGF-β-induced epithelial-to-mesenchymal transition in epithelial cells through suppressing the phosphorylation of Smad2/3 and AKT. The inhibitory effects of theophylline on the phosphorylation of Smad2/3 and AKT were recapitulated in BLM-treated lung tissues. Taken together, these results demonstrated that theophylline prevents pulmonary fibrosis by inhibiting Th17 differentiation and TGF-β signaling.
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- 2023
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23. Effect of Ambient Plasma Treatments on Thermal Conductivity and Fracture Toughness of Boron Nitride Nanosheets/Epoxy Nanocomposites
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Won-Jong Choi, Seul-Yi Lee, and Soo-Jin Park
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polymer-matrix composites (PMCs) ,interface ,thermal conductivity ,fracture toughness ,surface treatment ,Chemistry ,QD1-999 - Abstract
With the rapid growth in the miniaturization and integration of modern electronics, the dissipation of heat that would otherwise degrade the device efficiency and lifetime is a continuing challenge. In this respect, boron nitride nanosheets (BNNS) are of significant attraction as fillers for high thermal conductivity nanocomposites due to their high thermal stability, electrical insulation, and relatively high coefficient of thermal conductivity. Herein, the ambient plasma treatment of BNNS (PBNNS) for various treatment times is described for use as a reinforcement in epoxy nanocomposites. The PBNNS-loaded epoxy nanocomposites are successfully manufactured in order to investigate the thermal conductivity and fracture toughness. The results indicate that the PBNNS/epoxy nanocomposites subjected to 7 min plasma treatment exhibit the highest thermal conductivity and fracture toughness, with enhancements of 44 and 110%, respectively, compared to the neat nanocomposites. With these enhancements, the increases in surface free energy and wettability of the PBNNS/epoxy nanocomposites are shown to be attributable to the enhanced interfacial adhesion between the filler and matrix. It is demonstrated that the ambient plasma treatments enable the development of highly dispersed conductive networks in the PBNNS epoxy system.
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- 2022
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24. A Review on Non-Enzymatic Electrochemical Biosensors of Glucose Using Carbon Nanofiber Nanocomposites
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Ali Mohammadpour-Haratbar, Saeid Mohammadpour-Haratbar, Yasser Zare, Kyong Yop Rhee, and Soo-Jin Park
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carbon nanofiber ,electrochemical biosensors ,electrodes ,nanocomposite ,nanoparticles ,Biotechnology ,TP248.13-248.65 - Abstract
Diabetes mellitus has become a worldwide epidemic, and it is expected to become the seventh leading cause of death by 2030. In response to the increasing number of diabetes patients worldwide, glucose biosensors with high sensitivity and selectivity have been developed for rapid detection. The selectivity, high sensitivity, simplicity, and quick response of electrochemical biosensors have made them a popular choice in recent years. This review summarizes the recent developments in electrodes for non-enzymatic glucose detection using carbon nanofiber (CNF)-based nanocomposites. The electrochemical performance and limitations of enzymatic and non-enzymatic glucose biosensors are reviewed. Then, the recent developments in non-enzymatic glucose biosensors using CNF composites are discussed. The final section of the review provides a summary of the challenges and perspectives, for progress in non-enzymatic glucose biosensors.
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- 2022
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25. Recent Advanced Supercapacitor: A Review of Storage Mechanisms, Electrode Materials, Modification, and Perspectives
- Author
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Niraj Kumar, Su-Bin Kim, Seul-Yi Lee, and Soo-Jin Park
- Subjects
carbon-based materials ,metal oxides ,conductive polymers ,hybrid capacitors ,supercapacitors ,Chemistry ,QD1-999 - Abstract
In recent years, the development of energy storage devices has received much attention due to the increasing demand for renewable energy. Supercapacitors (SCs) have attracted considerable attention among various energy storage devices due to their high specific capacity, high power density, long cycle life, economic efficiency, environmental friendliness, high safety, and fast charge/discharge rates. SCs are devices that can store large amounts of electrical energy and release it quickly, making them ideal for use in a wide range of applications. They are often used in conjunction with batteries to provide a power boost when needed and can also be used as a standalone power source. They can be used in various potential applications, such as portable equipment, smart electronic systems, electric vehicles, and grid energy storage systems. There are a variety of materials that have been studied for use as SC electrodes, each with its advantages and limitations. The electrode material must have a high surface area to volume ratio to enable high energy storage densities. Additionally, the electrode material must be highly conductive to enable efficient charge transfer. Over the past several years, several novel materials have been developed which can be used to improve the capacitance of the SCs. This article reviews three types of SCs: electrochemical double-layer capacitors (EDLCs), pseudocapacitors, and hybrid supercapacitors, their respective development, energy storage mechanisms, and the latest research progress in material preparation and modification. In addition, it proposes potentially feasible solutions to the problems encountered during the development of supercapacitors and looks forward to the future development direction of SCs.
- Published
- 2022
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26. Mango Seed-Derived Hybrid Composites and Sodium Alginate Beads for the Efficient Uptake of 2,4,6-Trichlorophenol from Simulated Wastewater
- Author
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Asma Jabeen, Urooj Kamran, Saima Noreen, Soo-Jin Park, and Haq Nawaz Bhatti
- Subjects
mango seed shell ,hybrid composite ,alginate ,2,4,6-trichlorophenol ,adsorption ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
In this study, mango seed shell (MS)-based hybrid composite and composite beads (FeCl3-NaBH4/MS and Na-Alginate/MS) were designed. Batch and column experimental analyses were performed for the uptake of 2,4,6-trichlorophenol (2,4,6-TCP) from wastewater. The physicochemical characteristics of both composites were also examined. From the batch adsorption experiments, the best adsorption capacities of 28.77 mg/g and 27.42 mg/g were observed in basic media (pH 9–10) at 308 K for FeCl3-NaBH4/MS and 333 K for Na-Alginate/MS with 25 mg/L of 2,4,6-TCP concentration for 120 min. The rate of reaction was satisfactorily followed by the pseudo-second-order kinetics. Equilibrium models revealed that the mechanism of reaction followed the Langmuir isotherm. The thermodynamic study also indicated that the nature of the reaction was exothermic and spontaneous with both adsorbents. Desorption experiments were also carried out to investigate the reliability and reusability of the composites. Furthermore, the efficiency of the adsorbents was checked in the presence of different electrolytes and heavy metals. From the batch experimental study, the FeCl3-NaBH4/MS composite proved to be the best adsorbent for the removal of the 2,4,6-TCP pollutant, hence it is further selected for fixed-bed column experimentation. The column study data were analyzed using the BDST and Thomas models and the as-selected FeCl3-NaBH4/MS hybrid composites showed satisfactory results for the fixed-bed adsorption of the 2,4,6-TPC contaminants.
- Published
- 2022
- Full Text
- View/download PDF
27. Effective Conductivity of Carbon-Nanotube-Filled Systems by Interfacial Conductivity to Optimize Breast Cancer Cell Sensors
- Author
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Yasser Zare, Kyong-Yop Rhee, and Soo-Jin Park
- Subjects
conductive carbon nanotubes (CNTs) ,polymer nanocomposites ,incomplete interface ,effective conductivity ,interfacial conductivity ,Chemistry ,QD1-999 - Abstract
Interfacial conductivity and “Lc”, i.e., the least carbon-nanotube (CNT) length required for the operative transfer of CNT conductivity to the insulated medium, were used to establish the most effective CNT concentration and portion of CNTs needed for a network structure in polymer CNT nanocomposites (PCNT). The mentioned parameters and tunneling effect define the effective conductivity of PCNT. The impact of the parameters on the beginning of percolation, the net concentration, and the effective conductivity of PCNT was investigated and the outputs were explained. Moreover, the calculations of the beginning of percolation and the conductivity demonstrate that the experimental results and the developed equations are in acceptable agreement. A small “Lc” and high interfacial conductivity affect the beginning of percolation, the fraction of networked CNTs, and the effective conductivity. Additionally, a low tunneling resistivity, a wide contact diameter, and small tunnels produce a highly effective conductivity. The developed model can be used to optimize breast cancer cell sensors.
- Published
- 2022
- Full Text
- View/download PDF
28. Tensile Modulus of Polymer Halloysite Nanotube Systems Containing Filler–Interphase Networks for Biomedical Requests
- Author
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Yasser Zare, Kyong Yop Rhee, and Soo-Jin Park
- Subjects
halloysite nanotube (HNT) ,nanocomposite ,modulus ,interphase zone ,network ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
To date, there have been a limited number of studies modeling the tensile modulus in the polymer halloysite nanotube (HNT) systems before or after percolation onset. In this paper, an equation for a composite’s modulus post-percolation onset was developed for HNT-filled samples including the interphase and HNT network. The dispersed nanoparticles and adjoining interphase part were neglected, because they caused ineffective influences on the stiffness of the system after percolation onset. The developed model reflects the impacts of HNTs’ size, interphase depth, percolation onset and the volume shares and moduli of the HNT network and its adjacent interphase on the modulus of HNT-based systems. The impacts of issues on the nanocomposite modulus are defendable, confirming the effectiveness of the developed model. HNT length, interphase depth, HNT concentration, net modulus and net portion directly influenced the stiffness, while the HNT radius and percolation onset had inverse effects. Results show that there was a 142% improvement in the modulus of samples at an interphase depth of 40 nm. Moreover, the stiffness improved by 60% at a net modulus of 200 GPa, but it later exhibited a 180% enhancement at a net modulus of 1000 GPa. In addition, the experimental data for the modulus of numerous composites display fine agreement to the predictions, confirming the validity of the developed model.
- Published
- 2022
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29. Nitrogen and Sulfur Co-Doped Graphene Quantum Dots Anchored TiO2 Nanocomposites for Enhanced Photocatalytic Activity
- Author
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Jishu Rawal, Urooj Kamran, Mira Park, Bishweshwar Pant, and Soo-Jin Park
- Subjects
photocatalytic degradation ,graphene quantum dots ,nanocomposites ,free radical generation ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
Herein, nitrogen (N) and sulfur (S) co-doped graphene quantum dots (GQDs) using different one-dimensional (1-D) carbon nanomaterials as precursors were synthesized, followed by heterojunction formation with TiO2. GQDs exhibit unlike physiochemical properties due to the disproportionate ratio of N and S heteroatoms and dissimilar reaction parameters. Tailored type-II band gap (Eg) alignment was formed with narrowed Eg value that improves photogenerated electron transfer due to π-conjugation. GQDs-TiO2 nanocomposites exhibit remarkably high methylene blue (MB) degradation up to 99.78% with 2.3–3 times elevated rate constants as compared with TiO2. CNF-GQDs-TiO2 demonstrates the fastest MB degradation (60 min) due to the synergistic effect of nitrogen and sulfur doping, and is considered the most stable photocatalyst among prepared nanocomposites as tested up to three cyclic runs. Whereas, C–O–Ti bonds were not only responsible for nanocomposites strengthening but also provide a charge transfer pathway. Moreover, charge transport behavior, generation of active species, and reaction mechanism were scrutinized via free-radical scavenger analysis.
- Published
- 2022
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- View/download PDF
30. A Study on Pre-Oxidation of Petroleum Pitch-Based Activated Carbons for Electric Double-Layer Capacitors
- Author
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Jong-Woo Kim, Dae-Won Kim, Seul-Yi Lee, and Soo-Jin Park
- Subjects
pre-oxidation ,petroleum pitch-based activated carbons ,supercapacitors ,electric double-layer capacitors (EDLCs) ,microporous ,Organic chemistry ,QD241-441 - Abstract
Electric double-layer capacitors (EDLCs) are an excellent electrochemical energy storage system (ESS) because of their superior power density, faster charge–discharge ability, and longer cycle life compared to those of other EES systems. Activated carbons (ACs) have been mainly used as the electrode materials for EDLCs because of their high specific surface area, superior chemical stability, and low cost. Petroleum pitch (PP) is a graphitizable carbon that is a promising precursor for ACs because of its high carbon content, which is obtained as an abundant by-product during the distillation of petroleum. However, the processibility of PP is poor because of its stable structure. In this study, pre-oxidized PP-derived AC (OPP-AC) was prepared to investigate the effects of pre-oxidation on the electrochemical behaviors of PP. The specific surface area and pore size distribution of OPP-AC were lower and narrower, respectively, compared to the textural properties of untreated PP-derived AC (PP-AC). On the other hand, the specific capacitance of OPP-AC was 25% higher than that of PP-AC. These results revealed that pre-oxidation of PP induces a highly developed micropore structure of ACs, resulting in improved electrochemical performance.
- Published
- 2022
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31. Evaluation of the Wind Environment around Multiple Urban Canyons Using Numerical Modeling
- Author
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Minu Son, Jeong-In Lee, Jae-Jin Kim, Soo-Jin Park, Daegi Kim, and Do-Yong Kim
- Subjects
numerical analysis ,computational fluid dynamics model ,wind velocity components ,urban canyon ,step-up(down) canyons ,Meteorology. Climatology ,QC851-999 - Abstract
This study aimed to evaluate the wind environment in step-up and step-down urban canyons through a computational numerical experiment using the computational fluid dynamics (CFD) model. Spatial structural conditions were considered according to the location of high-rise buildings, and the changing wind patterns inside canyons were compared and analyzed by varying the building heights. Under the step-up to step-down condition, wind velocity inside the canyon weakened, a vertical vortex formed, and vertical air flow separated; additionally, in shallow and deep canyons, wind velocity and detailed flow differed slightly according to each additional condition. For the step-down to step-up condition, the building located in the center appeared to be isolated, and a general wind environment phenomenon consistent with the step-up and step-down structures was observed. However, depending on the isolated area, an additional roof-top canyon was formed, and the wind field in the canyon was found to affect the wind velocity and detailed flow in other canyons. The wind velocity components of the inflow and outflow winds into the canyon differed based on the step-up to step-down or step-down to step-up conditions, and according to the conditions in the first and second canyons. Furthermore, the vertical wind velocity components were greatly affected by the step-up and step-down structures. Accordingly, the height and structural location of the building could affect various phenomena, such as the separation of vortices and air currents inside the canyon, and a variable wind environment was formed according to a series of conditions for the building.
- Published
- 2022
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32. A Role of Activators for Efficient CO2 Affinity on Polyacrylonitrile-Based Porous Carbon Materials
- Author
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Urooj Kamran, Jang Rak Choi, and Soo-Jin Park
- Subjects
porous carbons ,activating agents ,CO2/N2 selectivity ,regenerability ,CO2 adsorption ,Chemistry ,QD1-999 - Abstract
Herein, we investigated polyacrylonitrile (PAN)-based porous activated carbon sorbents as an efficient candidate for CO2 capture. In this research, an easy and an economical method of chemical activation and carbonization was used to generate activated PAN precursor (PAN-C) adsorbents. The influence of various activators including NaOH, KOH, K2CO3, and KNO3 on the textural features of PAN-C and their CO2 adsorption performance under different temperatures was examined. Among the investigated adsorbents, PANC-NaOH and PANC-KOH exhibited high specific surface areas (2,012 and 3,072 m2 g−1), with high microporosity (0.82 and 1.15 cm3 g−1) and large amounts of carbon and nitrogen moieties. The PAN-C activated with NaOH and KOH showed maximum CO2 uptakes of 257 and 246 mg g−1 at 273 K and 163 and 155 mg g−1 at 298 K, 1 bar, respectively, which was much higher as compared to the inactivated PAN-C precursor (8.9 mg g−1 at 273 K and 1 bar). The heat of adsorption (Qst) was in the range 10.81–39.26 kJ mol−1, indicating the physisorption nature of the CO2 adsorption process. The PAN-C-based activated adsorbents demonstrated good regeneration ability over repeated adsorption cycles. The current study offers a facile two-step fabrication method to generate efficient activated porous carbon materials from inexpensive and readily available PAN for use as CO2 adsorbents in environmental applications.
- Published
- 2020
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33. Modeling the roles of carbon nanotubes and interphase dimensions in the conductivity of nanocomposites
- Author
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Yasser Zare, Kyong Yop Rhee, and Soo-Jin Park
- Subjects
Physics ,QC1-999 - Abstract
The influences of interphase regions on the percolation threshold and electrical conductivity of nanocomposites polymer/carbon nanotubes (CNT) nanocomposites (PCNT) have been ignored in previous articles, although the interphase layer around CNT can encourage the conductivity. In this paper, the dimensions of CNT and surrounding interphase suggest the percolation threshold of CNT in PCNT. The comparisons between predictions and experimental measurements in several samples confirm the suggested equation. Moreover, the effective volume fraction of CNT and the fraction of networked CNT in the presence of interphase zones are expressed. Finally, a model is developed to investigate the roles of CNT and interphase dimensions as well as percolation threshold and CNT conductivity in the conductivity of PCNT. Thin CNT and thick interphase increase the effective volume fraction of nanoparticles in PCNT, whereas the CNT length is ineffective. A thick interphase and a high concentration of thin and long CNT grow the percentage of networked CNT and the conductivity of PCNT. The conductivity directly correlates to the CNT conductivity, while the smallest percolation threshold causes the highest conductivity. Additionally, a high waviness worsens the percolation threshold, the network size and the CNT conductivity resulting in a poor conductivity in nanocomposites. Keywords: Polymer/CNT nanocomposites, Interphase, Electrical conductivity, Percolation threshold
- Published
- 2019
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34. Ginsenoside Rg3 promotes inflammation resolution through M2 macrophage polarization
- Author
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Saeromi Kang, Soo-Jin Park, Ae-Yeon Lee, Jin Huang, Hae-Young Chung, and Dong-Soon Im
- Subjects
ginseng ,ginsenoside Rg3 ,inflammation ,resolution ,Botany ,QK1-989 - Abstract
Background: Ginsenosides have been reported to have many health benefits, including anti-inflammatory effects, and the resolution of inflammation is now considered to be an active process driven by M2-type macrophages. In order to determine whether ginsenosides modulate macrophage phenotypes to reduce inflammation, 11 ginsenosides were studied with respect to macrophage polarization and the resolution of inflammation. Methods: Mouse peritoneal macrophages were polarized into M1 or M2 phenotypes. Reverse transcription-polymerase chain reaction, Western blotting, and measurement of nitric oxide (NO) and prostaglandin E2 levels were performed in vitro and in a zymosan-induced peritonitis C57BL/6 mouse model. Results: Ginsenoside Rg3 was identified as a proresolving ginseng compound based on the induction of M2 macrophage polarization. Ginsenoside Rg3 not only induced the expression of arginase-1 (a representative M2 marker gene), but also suppressed M1 marker genes, such as inducible NO synthase, and NO levels. The proresolving activity of ginsenoside Rg3 was also observed in vivo in a zymosan-induced peritonitis model. Ginsenoside Rg3 accelerated the resolution process when administered at peak inflammatory response into the peritoneal cavity. Conclusion: These results suggest that ginsenoside Rg3 induces the M2 polarization of macrophages and accelerates the resolution of inflammation. This finding opens a new avenue in ginseng pharmacology.
- Published
- 2018
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- View/download PDF
35. Recent Advances in MnOx/CeO2-Based Ternary Composites for Selective Catalytic Reduction of NOx by NH3: A Review
- Author
-
Hao Sun and Soo-Jin Park
- Subjects
MnOx/CeO2 composite ,catalysis ,NOx reduction ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
Recently, manganese oxides (MnOx)/cerium(IV) oxide (CeO2) composites have attracted widespread attention for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) with ammonia (NH3), which exhibit outstanding catalytic performance owing to unique features, such as a large oxygen storage capacity, excellent low-temperature activity, and strong mechanical strength. The intimate contact between the components can effectively accelerate the charge transfer to enhance the electron–hole separation efficiency. Nevertheless, MnOx/CeO2 still reveals some deficiencies in the practical application process because of poor thermal stability, and a low reduction efficiency. Constructing MnOx/CeO2 with other semiconductors is the most effective strategy to further improve catalytic performance. In this article, we discuss progress in the field of MnOx/CeO2-based ternary composites with an emphasis on the SCR of NOx by NH3. Recent progress in their fabrication and application, including suitable examples from the relevant literature, are analyzed and summarized. In addition, the interaction mechanisms between MnOx/CeO2 catalysts and NOx pollutants are comprehensively dissected. Finally, the review provides basic insights into prospects and challenges for the advancement of MnOx/CeO2-based ternary catalysts.
- Published
- 2021
- Full Text
- View/download PDF
36. A Study on Electron Acceptor of Carbonaceous Materials for Highly Efficient Hydrogen Uptakes
- Author
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Seul-Yi Lee, Ji-Hye Park, Young-Jung Heo, Eun-Sang Lee, and Soo-Jin Park
- Subjects
hydrogen storage ,oxygen-functional groups ,porous carbons ,pore size ,77 K ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
Significant efforts have been directed toward the identification of carbonaceous materials that can be utilized for hydrogen uptake in order to develop on-board automotive systems with a gravimetric capacity of 5.5 wt.%, thus meeting the U.S. Department of Energy technical targets. However, the capacity of hydrogen storage is limited by the weak interaction between hydrogen molecules and the carbon surface. Cigarette butts, which are the most abundant form of primary plastic waste, remain an intractable environmental pollution problem. To transform this source of waste into a valuable adsorbent for hydrogen uptake, we prepared several forms of oxygen-rich cigarette butt-derived porous carbon (CGB-AC, with the activation temperature range of 600 and 900 °C). Our experimental investigation revealed that the specific surface area increased from 600 to 700 °C and then decreased as the temperature rose to 900 °C. In contrast, the oxygen contents gradually decreased with increasing activation temperature. CGB-AC700 had the highest H2 excess uptake (QExcess) of 8.54 wt.% at 77 K and 20 bar, which was much higher than that of porous carbon reported in the previous studies. We found that the dynamic interaction between the porosity and the oxygen content determined the hydrogen storage capacity. The underlying mechanisms proposed in the present study would be useful in the design of efficient hydrogen storage because they explain the interaction between positive carbonaceous materials and negative hydrogen molecules in quadrupole orbitals.
- Published
- 2021
- Full Text
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37. Effects of Fences and Green Zones on the Air Flow and PM2.5 Concentration around a School in a Building-Congested District
- Author
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Soo-Jin Park, Geon Kang, Wonsik Choi, Do-Yong Kim, Jinsoo Kim, and Jae-Jin Kim
- Subjects
urban area ,flows around buildings ,fine particulate matter (PM2.5) concentration ,fence effects ,CFD model ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
We investigated the effects of wall- and tree-type fences on the airflow and fine particular matter (PM2.5) concentration around a school using a computational fluid dynamics (CFD) model. First, we validated the simulated wind speeds and PM2.5 concentrations against measured values, and the results satisfied the recommended criteria of the statistical validation indices used. Then, we evaluated the fence effects for 16 inflow directions by conducting numerical simulations with different fence types and heights. With east–southeasterly inflow, relatively high PM2.5 from the road was transported to the school. However, the wall-type fence prevented the PM2.5 from the road from entering the school, and the PM2.5 concentration decreased significantly downwind of the fence. With east–northeasterly inflow, the horizontal wind speed decreased due to the drag caused by the tree-type fence, resulting in a shift in the flow convergence region. The PM2.5 concentration decreased in the region of strengthened upward flow. This occurred because the number of pollutants transported from the background decreased. A comparison of the two fence types revealed that the effect of the tree-type fence on inbound pollutants was more significant, due to increased upward flows, than the effect of the wall-type fence.
- Published
- 2021
- Full Text
- View/download PDF
38. Roles of Small Polyetherimide Moieties on Thermal Stability and Fracture Toughness of Epoxy Blends
- Author
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Seul-Yi Lee, Min-Joo Kang, Seong-Hwang Kim, Kyong Yop Rhee, Jong-Hoon Lee, and Soo-Jin Park
- Subjects
epoxy resins ,polyetherimide ,thermal stability ,fracture toughness ,Organic chemistry ,QD241-441 - Abstract
Bisphenol A diglycidyl ether (DGEBA) was blended with polyetherimide (PEI) as a thermoplastic toughener for thermal stability and mechanical properties as a function of PEI contents. The thermal stability and mechanical properties were investigated using a thermogravimetric analyzer (TGA) and a universal test machine, respectively. The TGA results indicate that PEI addition enhanced the thermal stability of the epoxy resins in terms of the integral procedural decomposition temperature (IPDT) and pyrolysis activation energy (Et). The IPDT and Et values of the DGEBA/PEI blends containing 2 wt% of PEI increased by 2% and 22%, respectively, compared to those of neat DGEBA. Moreover, the critical stress intensity factor and critical strain energy release rate for the DGEBA/PEI blends containing 2 wt% of PEI increased by 83% and 194%, respectively, compared to those of neat DGEBA. These results demonstrate that PEI plays a key role in enhancing the flexural strength and fracture toughness of epoxy blends. This can be attributed to the newly formed semi-interpenetrating polymer networks (semi-IPNs) composed of the epoxy network and linear PEI.
- Published
- 2021
- Full Text
- View/download PDF
39. Kurarinone Attenuates BLM-Induced Pulmonary Fibrosis via Inhibiting TGF-β Signaling Pathways
- Author
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Soo-Jin Park, Tae-hyoun Kim, Kiram Lee, Min-Ah Kang, Hyun-Jae Jang, Hyung-Won Ryu, Sei-Ryang Oh, and Hyun-Jun Lee
- Subjects
kurarinone ,pulmonary fibrosis ,TGF-β ,epithelial–mesenchymal transition ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Idiopathic pulmonary fibrosis (IPF) is a refractory interstitial lung disease for which there is no effective treatment. Although the pathogenesis of IPF is not fully understood, TGF-β and epithelial–mesenchymal transition (EMT) have been shown to be involved in the fibrotic changes of lung tissues. Kurarinone is a prenylated flavonoid isolated from Sophora Flavescens with antioxidant and anti-inflammatory properties. In this study, we investigated the effect of kurarinone on pulmonary fibrosis. Kurarinone suppressed the TGF-β-induced EMT of lung epithelial cells. To assess the therapeutic effects of kurarinone in bleomycin (BLM)-induced pulmonary fibrosis, mice were treated with kurarinone daily for 2 weeks starting 7 days after BLM instillation. Oral administration of kurarinone attenuated the fibrotic changes of lung tissues, including accumulation of collagen and improved mechanical pulmonary functions. Mechanistically, kurarinone suppressed phosphorylation of Smad2/3 and AKT induced by TGF-β1 in lung epithelial cells, as well as in lung tissues treated with BLM. Taken together, these results suggest that kurarinone has a therapeutic effect on pulmonary fibrosis via suppressing TGF-β signaling pathways and may be a novel drug candidate for pulmonary fibrosis.
- Published
- 2021
- Full Text
- View/download PDF
40. Improved Hygroscopicity and Bioavailability of Solid Dispersion of Red Ginseng Extract with Silicon Dioxide
- Author
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Sojeong Jin, Chul Haeng Lee, Dong Yu Lim, Jaehyeok Lee, Soo-Jin Park, Im-Sook Song, and Min-Koo Choi
- Subjects
Korean red ginseng extract ,solid dispersion formulation ,hygroscopicity ,intestinal permeability ,oral bioavailability ,Pharmacy and materia medica ,RS1-441 - Abstract
This study aims to develop a powder formulation for the Korean red ginseng extract (RGE) and to evaluate its in vitro and in vivo formulation characteristics. The solid dispersion of RGE was prepared with hydrophilic carriers using a freeze-drying method. After conducting the water sorption–desorption isothermogram (relative humidity between 30 and 70% RH), differential scanning calorimetry thermal behavior, dissolution test, and intestinal permeation study, a solid dispersion formulation of RGE and silicon dioxide (RGE-SiO2) was selected. RGE-SiO2 formulation increased intestinal permeability of ginsenoside Rb1 (GRb1), GRb2, GRc, and GRd by 1.6-fold in rat jejunal segments as measured by the Ussing chamber system. A 1.6- to 1.8-fold increase in plasma exposure of GRb1, GRb2, GRc, and GRd in rats was observed following oral administration of RGE-SiO2 (375 mg/kg as RGE). No significant difference was observed in the time to reach maximum concentration (Tmax) and half-life in comparison to those in RGE administered rats (375 mg/kg). In conclusion, formulating solid dispersion of RGE with amorphous SiO2, the powder formulation of RGE was successfully formulated with improved hygroscopicity, increased intestinal permeability, and enhanced oral bioavailability and is therefore suitable for processing solid formulations of RGE product.
- Published
- 2021
- Full Text
- View/download PDF
41. Effect of Atmospheric-Pressure Plasma Treatments on Fracture Toughness of Carbon Fibers-Reinforced Composites
- Author
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Won-Jong Kim, Young-Jung Heo, Jong-Hoon Lee, Kyong Yop Rhee, and Soo-Jin Park
- Subjects
polymer–matrix composites (PMCs) ,fracture toughness ,surface properties ,Organic chemistry ,QD241-441 - Abstract
In this study, nano-scale fillers are added to epoxy matrix-based carbon fibers-reinforced composites (CFRPs) to improve the mechanical properties of multi-scale composites. Single-walled carbon nanotubes (SWCNTs) used as nano-scale fillers are treated with atmospheric-pressure plasma to introduce oxygen functional groups on the fillers’ surface to increase the surface free energy and polar component, which relates to the mechanical properties of multi-scale composites. In addition, the effect of dispersibility was analyzed through the fracture surfaces of multi-scale composites containing atmospheric-pressure plasma-treated SWCNTs (P-SWCNTs) under high load conditions. The fillers content has an optimum weight percent load at 0.5 wt.% and the fracture toughness (KIC) method is used to demonstrate an improvement in mechanical properties. Here, KIC was calculated by three equations based on different models and we analyzed the correlation between mechanical properties and surface treatment. Compared to the composites of untreated SWCNTs, the KIC value is improved by 23.7%, suggesting improved mechanical properties by introducing selective functional groups through surface control technology to improve interfacial interactions within multi-scale composites.
- Published
- 2021
- Full Text
- View/download PDF
42. Highly Efficient Visible Blue-Emitting Black Phosphorus Quantum Dot: Mussel-Inspired Surface Functionalization for Bioapplications
- Author
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Miyeon Lee, Young Ho Park, Eun Bi Kang, Ari Chae, Yujin Choi, Seongho Jo, Yu Jin Kim, Soo-Jin Park, Byunggak Min, Tae Kyu An, Jihoon Lee, Su-Il In, Sang Youl Kim, Sung Young Park, and Insik In
- Subjects
Chemistry ,QD1-999 - Published
- 2017
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43. Facile Synthesis of MgO-Modified Carbon Adsorbents with Microwave- Assisted Methods: Effect of MgO Particles and Porosities on CO2 Capture
- Author
-
Young-Jung Heo and Soo-Jin Park
- Subjects
Medicine ,Science - Abstract
Abstract In this study, magnesium oxide (MgO)-modified carbon adsorbents were fabricated using a nitrogen-enriched carbon precursor by microwave-assisted irradiation for CO2 capture. The X-ray diffraction (XRD) patterns showed the characteristic diffraction peaks of MgO at 43° and 62.5°, and no impurities were apparent. By changing the microwave reaction time, the spherical structure of the parent material was transformed to a hybrid structure with MgO crystalline particles in a carbon matrix. The morphology evolution and properties of the prepared materials were also investigated using transmission electron microscopy and N2 adsorption, respectively. On optimising the conditions, the prepared sample attained a high CO2 uptake of 1.22 mmol/g (5.3 wt.%) under flue gas conditions (15% CO2 in N2). It was found that MgO affected the CO2 capture behaviour by enhancing the fundamental characteristics of the carbon surfaces.
- Published
- 2017
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44. A developed equation for electrical conductivity of polymer carbon nanotubes (CNT) nanocomposites based on Halpin-Tsai model
- Author
-
Yasser Zare, Kyong Yop Rhee, and Soo-Jin Park
- Subjects
Physics ,QC1-999 - Abstract
This paper expresses a simple equation for conductivity of polymer carbon nanotubes (CNT) nanocomposites (PCNT) based on Halpin-Tsai model supposing the volume fraction of networked CNT, CNT conductivity, CNT size and tunneling dimensions between adjacent CNT. The experimental results of several samples and the effects of all parameters on the conductivity examine the predictions of developed model. Long CNT, thick interphase, thin CNT, high percentage of networked CNT, short tunneling distance, poor waviness and large tunneling diameter advantageously improve the conductivity. The suitable agreements between experimental data and calculations as well as the sensible roles of all parameters in the conductivity justify the developed model. The developed model can provide the optimized levels of parameters introducing the most desirable conductivity. Keywords: Polymer CNT nanocomposites, Conductivity, Tunneling effect, Interphase
- Published
- 2019
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- View/download PDF
45. 2-Arachidonyl-lysophosphatidylethanolamine Induces Anti-Inflammatory Effects on Macrophages and in Carrageenan-Induced Paw Edema
- Author
-
Soo-Jin Park and Dong-Soon Im
- Subjects
lysolipid ,2-arachidonyl-lysophosphatidylethanolamine ,inflammation ,edema ,macrophage ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
2-Arachidonyl-lysophosphatidylethanolamine, shortly 2-ARA-LPE, is a polyunsaturated lysophosphatidylethanolamine. 2-ARA-LPE has a very long chain arachidonic acid, formed by an ester bond at the sn-2 position. It has been reported that 2-ARA-LPE has anti-inflammatory effects in a zymosan-induced peritonitis model. However, it’s action mechanisms are poorly investigated. Recently, resolution of inflammation is considered to be an active process driven by M2 polarized macrophages. Therefore, we have investigated whether 2-ARA-LPE acts on macrophages for anti-inflammation, whether 2-ARA-LPE modulates macrophage phenotypes to reduce inflammation, and whether 2-ARA-LPE is anti-inflammatory in a carrageenan-induced paw edema model. In mouse peritoneal macrophages, 2-ARA-LPE was found to inhibit lipopolysaccharide (LPS)-induced M1 macrophage polarization, but not induce M2 polarization. 2-ARA-LPE inhibited the inductions of inducible nitric oxide synthase and cyclooxygenase-2 in mouse peritoneal macrophages at the mRNA and protein levels. Furthermore, products of the two genes, nitric oxide and prostaglandin E2, were also inhibited by 2-ARA-LPE. However, 1-oleoyl-LPE did not show any activity on the macrophage polarization and inflammatory responses. The anti-inflammatory activity of 2-ARA-LPE was also verified in vivo in a carrageenan-induced paw edema model. 2-ARA-LPE inhibits LPS-induced M1 polarization, which contributes to anti-inflammation and suppresses the carrageenan-induced paw edema in vivo.
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- 2021
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46. Enhanced Bioavailability and Efficacy of Silymarin Solid Dispersion in Rats with Acetaminophen-Induced Hepatotoxicity
- Author
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Im-Sook Song, So-Jeong Nam, Ji-Hyeon Jeon, Soo-Jin Park, and Min-Koo Choi
- Subjects
silymarin ,D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) ,liver distribution ,acetaminophen-induced hepatotoxicity ,Pharmacy and materia medica ,RS1-441 - Abstract
We evaluated the bioavailability, liver distribution, and efficacy of silymarin-D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) solid dispersion (silymarin-SD) in rats with acetaminophen-induced hepatotoxicity (APAP) compared with silymarin alone. The solubility of silybin, the major and active component of silymarin, in the silymarin-SD group increased 23-fold compared with the silymarin group. The absorptive permeability of silybin increased by 4.6-fold and its efflux ratio decreased from 5.5 to 0.6 in the presence of TPGS. The results suggested that TPGS functioned as a solubilizing agent and permeation enhancer by inhibiting efflux pump. Thus, silybin concentrations in plasma and liver were increased in the silymarin-SD group and liver distribution increased 3.4-fold after repeated oral administration of silymarin-SD (20 mg/kg as silybin) for five consecutive days compared with that of silymarin alone (20 mg/kg as silybin). Based on higher liver silybin concentrations in the silymarin-SD group, the therapeutic effects of silymarin-SD in hepatotoxic rats were evaluated and compared with silymarin administration only. Elevated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels were significantly decreased by silymarin-SD, silymarin, and TPGS treatments, but these decreases were much higher in silymarin-SD animals than in those treated with silymarin or TPGS. In conclusion, silymarin-SD (20 mg/kg as silybin, three times per day for 5 days) exhibited hepatoprotective properties toward hepatotoxic rats and these properties were superior to silymarin alone, which may be attributed to increased solubility, enhanced intestinal permeability, and increased liver distribution of the silymarin-SD formulation.
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- 2021
- Full Text
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47. Involvement of Organic Anion Transporters in the Pharmacokinetics and Drug Interaction of Rosmarinic Acid
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Yun Ju Kang, Chul Haeng Lee, Soo-Jin Park, Hye Suk Lee, Min-Koo Choi, and Im-Sook Song
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rosmarinic acid ,organic anion transporter (OAT) ,pharmacokinetics ,herb-drug interaction ,Pharmacy and materia medica ,RS1-441 - Abstract
We investigated the involvement of drug transporters in the pharmacokinetics of rosmarinic acid in rats as well as the transporter-mediated drug interaction potential of rosmarinic acid in HEK293 cells overexpressing clinically important solute carrier transporters and also in rats. Intravenously injected rosmarinic acid showed bi-exponential decay and unchanged rosmarinic acid was mainly eliminated by urinary excretion, suggesting the involvement of transporters in its renal excretion. Rosmarinic acid showed organic anion transporter (OAT)1-mediated active transport with a Km of 26.5 μM and a Vmax of 69.0 pmol/min in HEK293 cells overexpressing OAT1, and the plasma concentrations of rosmarinic acid were increased by the co-injection of probenecid because of decreased renal excretion due to OAT1 inhibition. Rosmarinic acid inhibited the transport activities of OAT1, OAT3, organic anion transporting polypeptide (OATP)1B1, and OATP1B3 with IC50 values of 60.6 μM, 1.52 μM, 74.8 μM, and 91.3 μM, respectively, and the inhibitory effect of rosmarinic acid on OAT3 transport activity caused an in vivo pharmacokinetic interaction with furosemide by inhibiting its renal excretion and by increasing its plasma concentration. In conclusion, OAT1 and OAT3 are the major transporters that may regulate the pharmacokinetic properties of rosmarinic acid and may cause herb-drug interactions with rosmarinic acid, although their clinical relevance awaits further evaluation.
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- 2021
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48. The Role of CO2 as a Mild Oxidant in Oxidation and Dehydrogenation over Catalysts: A Review
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Sheikh Tareq Rahman, Jang-Rak Choi, Jong-Hoon Lee, and Soo-Jin Park
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carbon dioxide ,soft oxidant ,oxidation ,dehydrogenation ,nano-catalyst ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
Carbon dioxide (CO2) is widely used as an enhancer for industrial applications, enabling the economical and energy-efficient synthesis of a wide variety of chemicals and reducing the CO2 levels in the environment. CO2 has been used as an enhancer in a catalytic system which has revived the exploitation of energy-extensive reactions and carry chemical products. CO2 oxidative dehydrogenation is a greener alternative to the classical dehydrogenation method. The availability, cost, safety, and soft oxidizing properties of CO2, with the assistance of appropriate catalysts at an industrial scale, can lead to breakthroughs in the pharmaceutical, polymer, and fuel industries. Thus, in this review, we focus on several applications of CO2 in oxidation and oxidative dehydrogenation systems. These processes and catalytic technologies can reduce the cost of utilizing CO2 in chemical and fuel production, which may lead to commercial applications in the imminent future.
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- 2020
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49. Activated Carbon/MnO2 Composites as Electrode for High Performance Supercapacitors
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Jang Rak Choi, Ji Won Lee, Guijun Yang, Young-Jung Heo, and Soo-Jin Park
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activated carbon ,manganese dioxide ,electrochemical performance ,supercapacitor ,Chemical technology ,TP1-1185 ,Chemistry ,QD1-999 - Abstract
Activated carbon (AC) was synthesized with various weight ratios of manganese dioxide (MO) through a simple hydrothermal approach. The electrochemical performance of the synthesized activated carbon/MnO2 composites was investigated. The effect of the activated carbon/MnO2 (AM) ratio on the electrochemical properties of the activated carbon/MnO2 composites and the pore structure was also examined. The results show that the specific capacitance of the activated carbon material has been improved after the addition of MO. The as-synthesized composite material exhibits specific capacitance of 60.3 F g−1 at 1 A g−1, as well as stable cycle performance and 99.6% capacitance retention over 5000 cycles.
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- 2020
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50. Effect of Processing Parameters on the Thermal and Electrical Properties of Electroless Nickel-Phosphorus Plated Carbon Fiber Heating Elements
- Author
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Bo-Kyung Choi, Soo-Jin Park, and Min-Kang Seo
- Subjects
processing parameter ,carbon fibers ,electroless ni-p plated ,thermal ,electrical ,Organic chemistry ,QD241-441 - Abstract
Carbon fibers (CFs) were plated with nickel-phosphorus (Ni-P) using an electroless plating process. The effects of the process parameters such as heat treatment temperature, heat treatment time, and the pH of the plating bath on electroless Ni-P plating were investigated. The structure, elemental composition, and thermal and electrical properties of Ni-P plated CFs (MCF) were characterized by X-ray diffraction (XRD), a four-probe volume resistivity tester, and an infrared thermal imaging camera, respectively. The XRD indicated the presence of amorphous and crystalline phases of Ni and Ni-P. The MCF were able to perform at high temperatures because of their higher thermal conductivity. A heat treatment temperature of 300 °C, a heat treatment time of 4 h, and a pH of 8.5 were found to be optimum for obtaining MCF with desirable thermal and electrical properties.
- Published
- 2020
- Full Text
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