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51.
Eui-Baek Byun Ha-Yeon Song Woo Sik Kim Jeong Moo Han Ho Seong Seo Woo Yong Park Kwangwook Kim Eui-Hong Byun 《Molecules (Basel, Switzerland)》2021,26(6)
Although our previous study revealed that gamma-irradiated chrysin enhanced anti-inflammatory activity compared to intact chrysin, it remains unclear whether the chrysin derivative, CM1, produced by gamma irradiation, negatively regulates toll-like receptor (TLR) signaling. In this study, we investigated the molecular basis for the downregulation of TLR4 signal transduction by CM1 in macrophages. We initially determined the appropriate concentration of CM1 and found no cellular toxicity below 2 μg/mL. Upon stimulation with lipopolysaccharide (LPS), CM1 modulated LPS-stimulated inflammatory action by suppressing the release of proinflammatory mediators (cytokines TNF-α and IL-6) and nitric oxide (NO) and downregulated the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. Furthermore, CM1 markedly elevated the expression of the TLR negative regulator toll-interacting protein (Tollip) in dose- and time-dependent manners. LPS-induced expression of cell surface molecules (CD80, CD86, and MHC class I/II), proinflammatory cytokines (TNF-α and IL-6), COX-2, and iNOS-mediated NO were inhibited by CM1; these effects were prevented by the knockdown of Tollip expression. Additionally, CM1 did not affect the downregulation of LPS-induced expression of MAPKs and NF-κB signaling in Tollip-downregulated cells. These findings provide insight into effective therapeutic intervention of inflammatory disease by increasing the understanding of the negative regulation of TLR signaling induced by CM1. 相似文献
52.
53.
Spectroscopic Monitoring of the Acidity of Water Films on Ru(0001): Orientation‐Specific Acidity of Adsorbed Water 下载免费PDF全文
Youngsoon Kim Sunghwan Shin Dr. Eui‐Seong Moon Prof. Heon Kang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(12):3376-3383
We examined the acid–base properties of water films adsorbed onto a Ru(0001) substrate by using surface spectroscopic methods in vacuum environments. Ammonia adsorption experiments combined with low‐energy sputtering (LES), reactive ion scattering (RIS), reflection–absorption infrared spectroscopy (RAIRS) and temperature‐programmed desorption (TPD) measurements showed that the adsorbed water is acidic enough to transfer protons to ammonia. Only the water molecules in an intact water monolayer and water clusters larger than the hexamer exhibit such acidity, whereas small clusters, a thick ice film or a partially dissociated water monolayer that contains OH, H2O and H species are not acidic. The observations indicate the orientation‐specific acidity of adsorbed water. The acidity stems from water molecules with H‐down adsorption geometry present in the monolayer. However, the dissociation of water into H and OH on the surface does not promote but rather suppresses the proton transfer to ammonia. 相似文献
54.
Frontispiece: In Vivo Residue‐Specific Dopa‐Incorporated Engineered Mussel Bioglue with Enhanced Adhesion and Water Resistance 下载免费PDF全文
55.
Jinhwang Kim Hyeon-Min Cha Mikyung Park Dileep K. Singh Gi H. Bae Seong H. Kim Ikyon Kim 《Journal of heterocyclic chemistry》2020,57(9):3279-3293
A new chemical space was generated via C2-functionalization of 3-arylbenzofurans. Mannich reaction of 3-arylbenzofurans with secondary amines and formaldehyde allowed for installation of aminomethyl unit at C2 position of benzofurans. A formyl group at C2 site introduced as a result of Vilsmeier-Haack formylation of 3-arylbenzofurans was employed as a reacting partner for three-component Kabachnik-Fields reaction with various amines and triethyl phosphite to give a wide variety of aminomethylphosphonates. Furthermore, several benzo[d]oxazoles and pyrrolo[1,2-a]quinoxalines were prepared by using the formyl group. Biological screening of the synthesized compounds revealed that the benzofuran bearing a pyrrolo[1,2-a]quinoxaline moiety ( 5b ) most potently inhibited the viability of human blood cancer cells, but not solid tumor cells. Caspase activity assay, analysis of Annexin V-positive cells, and Western blot analysis indicated that 5b -induced death of human lymphoma U937 cells could result from its potential to induce the caspase-dependent apoptotic death of blood cancer cells with inhibition of ERK activation. 相似文献
56.
Young-Hun Cho Jae-Gyoung Seong Jae-Hyun Noh Da-Young Kim Yong-Sik Chung Tae Hoon Ko Byoung-Suhk Kim 《Molecules (Basel, Switzerland)》2020,25(24)
In this work, we report the carbon fiber-based wire-type asymmetric supercapacitors (ASCs). The highly conductive carbon fibers were prepared by the carbonized and graphitized process using the polyimide (PI) as a carbon fiber precursor. To assemble the ASC device, the CoMnO2-coated and Fe2O3-coated carbon fibers were used as the cathode and the anode materials, respectively. Herein, the nanostructured CoMnO2 were directly deposited onto carbon fibers by a chemical oxidation route without high temperature treatment in presence of ammonium persulfate (APS) as an oxidizing agent. FE-SEM analysis confirmed that the CoMnO2-coated carbon fiber electrode exhibited the porous hierarchical interconnected nanosheet structures, depending on the added amount of APS, and Fe2O3-coated carbon fiber electrode showed a uniform distribution of porous Fe2O3 nanorods over the surface of carbon fibers. The electrochemical properties of the CoMnO2-coated carbon fiber with the concentration of 6 mmol APS presented the enhanced electrochemical activity, probably due to its porous morphologies and good conductivity. Further, to reduce the interfacial contact resistance as well as improve the adhesion between transition metal nanostructures and carbon fibers, the carbon fibers were pre-coated with the Ni layer as a seed layer using an electrochemical deposition method. The fabricated ASC device delivered a specific capacitance of 221 F g−1 at 0.7 A g−1 and good rate capability of 34.8% at 4.9 A g−1. Moreover, the wire-type device displayed the superior energy density of 60.2 Wh kg−1 at a power density of 490 W kg−1 and excellent capacitance retention of 95% up to 3000 charge/discharge cycles. 相似文献
57.
Reka Geczy Niels Johan Christensen Kim K. Rasmussen Ildik Klomista Manish K. Tiwari Pratik Shah Seong Wook Yang Morten J. Bjerrum Peter W. Thulstrup 《Angewandte Chemie (International ed. in English)》2020,59(37):16091-16097
Fluorescent, DNA‐stabilized silver nanoclusters (DNA‐AgNCs) are applied in a range of applications within nanoscience and nanotechnology. However, their diverse optical properties, mechanism of formation, and aspects of their composition remain unexplored, making the rational design of nanocluster probes challenging. Herein, a synthetic procedure is described for obtaining a high yield of emissive DNA‐AgNCs with a C‐loop hairpin DNA sequence, with subsequent purification by size‐exclusion chromatography (SEC). Through a combination of optical spectroscopy, gel electrophoresis, inductively coupled plasma mass spectrometry (ICP‐MS), and small‐angle X‐ray scattering (SAXS) in conjunction with the systematic study of various DNA sequences, the low‐resolution structure and mechanism of the formation of AgNCs were investigated. Data indicate that fluorescent DNA‐AgNCs self‐assemble by a head‐to‐head binding of two DNA hairpins, bridged by a silver nanocluster, resulting in the modelling of a dimeric structure harboring an Ag12 cluster. 相似文献
58.
Nam Sook Kim Sun Hee Moon Hwan Seong Choi Ji Hyun Lee Seongsoo Park Hoil Kang 《Journal of separation science》2020,43(14):2750-2765
An analytical method for the simultaneous and reliable determination of 20 antigout and antiosteoporosis pharmaceutical compounds in adulterated health food products was developed using liquid chromatography with electrospray ionization tandem mass spectrometry and liquid chromatography with quadrupole‐time‐of‐flight mass spectrometry. The method was validated through the determination of specificity, linearity, limit of detection, and limit of quantification, method detection limit, method quantitation limit, precision, accuracy, recovery, and stability. The matrix effect was also determined. The validation results of the developed method are as follows: for solid and liquid blank samples, limits of detection ranged from 0.05 to 5.00 ng/mL and limits of quantification ranged from 0.15 to 15.00 ng/mL. Linearity was acceptable, and the correlation coefficients (R2) were ≥0.99 for all target compounds. Both intra and interday precision were less than 9.16% RSD, and accuracies ranged from 95.31 to 116.68%. Mean recoveries for different types of dietary supplements classified as powders, liquids, tablets, and capsules were found to be 80.81 to 117.62% with less than 15.00% relative standard deviation. The stability of the standard mixture solution was less than 11.72% relative standard deviation after 48 h. By the proposed method, the presence of dexamethasone was determined in seized herbal food products at concentrations that ranged from 126 to 215 µg/g. 相似文献
59.
Poly(ethylene glycol)‐crosslinked multimeric C60 was developed for use in photothermal/photodynamic therapy of malignant cells. We showed that: (i) the tumor surface temperature on KB tumor‐bearing nude mice treated with multimeric C60 reached about 44 °C; (ii) this hyperthermic condition and tremendous singlet oxygen generation from multimeric C60 resulted in significant tumor volume regression in KB tumor‐bearing nude mice; and (iii) multimeric C60 also efficiently inhibited arthritic progress in the arthritis‐induced DBA/1 J mice model. This multimeric C60 may be useful for photothermal/photodynamic cell ablation in various malignant cells. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
60.
Tae Woo Kim Eun‐Jin Oh Ah‐Young Jee Seung Tae Lim Dae Hoon Park Minyung Lee Sang‐Hoon Hyun Prof. Jin‐Ho Choy Prof. Seong‐Ju Hwang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(41):10752-10761
A colloidal suspension of exfoliated, layered cobalt oxide nanosheets has been synthesized through the intercalation of quaternary tetramethylammonium ions into protonated lithium cobalt oxide. According to atomic force microscopy, exfoliated nanosheets of layered cobalt oxide show a plateau‐like height profile with nanometer‐level height, underscoring the formation of unilamellar 2D nanosheets. The exfoliation of layered cobalt oxide was cross‐confirmed by X‐ray diffraction, UV/Vis spectroscopy, and transmission electron microscopy. The maintenance of the hexagonal in‐plane structure of the cobalt oxide lattice after the exfoliation process was evidenced by selected‐area electron diffraction and Co K‐edge X‐ray absorption near‐edge structure analysis. The zeta‐potential measurements clearly demonstrated the negative surface charge of cobalt oxide nanosheets. Adopting the nanosheets of layered cobalt oxide as a precursor, we were able to prepare the monodisperse CoO nanocrystals with a particle size of ≈10 nm as well as the heterolayered film composed of cobalt oxide monolayer and polycation. 相似文献