92 results on '"Lim HD"'
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2. Exploiting Lithium–Ether Co-Intercalation in Graphite for High-Power Lithium-Ion Batteries
- Author
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Kim, H, Lim, K, Yoon, G, Park, JH, Ku, K, Lim, HD, Sung, YE, and Kang, K
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co-intercalation ,first-principles calculations ,graphite ,high-power batteries ,lithium-ion batteries ,Macromolecular and Materials Chemistry ,Materials Engineering ,Interdisciplinary Engineering - Abstract
The intercalation of lithium ions into graphite electrode is the key underlying mechanism of modern lithium-ion batteries. However, co-intercalation of lithium-ions and solvent into graphite is considered undesirable because it can trigger the exfoliation of graphene layers and destroy the graphite crystal, resulting in poor cycle life. Here, it is demonstrated that the [lithium–solvent]+ intercalation does not necessarily cause exfoliation of the graphite electrode and can be remarkably reversible with appropriate solvent selection. First-principles calculations suggest that the chemical compatibility of the graphite host and [lithium–solvent]+ complex ion strongly affects the reversibility of the co-intercalation, and comparative experiments confirm this phenomenon. Moreover, it is revealed that [lithium–ether]+ co-intercalation of natural graphite electrode enables much higher power capability than normal lithium intercalation, without the risk of lithium metal plating, with retention of ≈87% of the theoretical capacity at current density of 1 A g−1. This unusual high rate capability of the co-intercalation is attributed to the (i) absence of the desolvation step, (ii) negligible formation of the solid–electrolyte interphase on graphite surface, and (iii) fast charge-transfer kinetics. This work constitutes the first step toward the utilization of fast and reversible [lithium–solvent]+ complex ion intercalation chemistry in graphite for rechargeable battery technology.
- Published
- 2017
3. Distinct antagonist-bound inactive states underlie the divergence in the structures of the dopamine D2 and D3 receptors
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Jonathan A. Javitch, Lim Hd, Ara M. Abramyan, Lei Shi, Ravi Kumar Verma, and Lane
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Eticlopride ,Chemistry ,Stereochemistry ,Drug discovery ,Dopamine receptor D2 ,Mutagenesis ,Antagonist ,Receptor ,Divergence ,G protein-coupled receptor - Abstract
Understanding how crystal structures reflect the range of possible G protein-coupled receptor (GPCR) states is critical for rational drug discovery (RDD). Combining computational simulations with mutagenesis and binding studies, we find that the structure of the dopamine D2 receptor (D2R)/risperidone complex captures an inactive receptor conformation that accommodates some but not all antagonist scaffolds. Indeed, we find that eticlopride binds D2R in a configuration very similar to that seen in the D3R structure, in a pose that is incompatible with the D2R/risperidone structure. Moreover, our simulations reveal that extracellular loops 1 and 2 (EL1 and EL2) are highly dynamic, with spontaneous transitions of EL2 from the helical conformation in the D2R/risperidone structure to an extended conformation similar to that in the D3R/eticlopride structure. Our results highlight previously unappreciated conformational diversity and dynamics in the inactive state of a GPCR with potential functional implications. These findings are also of paramount importance for RDD as limiting a virtual screen to one state will miss relevant ligands.
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- 2019
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4. Reaction chemistry in rechargeable Li-O2batteries
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Lim, HD, Lee, B, Bae, Y, Park, H, Ko, Y, Kim, H, Kim, J, and Kang, K
- Abstract
© 2017 The Royal Society of Chemistry. The seemingly simple reaction of Li-O2batteries involving lithium and oxygen makes this chemistry attractive for high-energy-density storage systems; however, achieving this reaction in practical rechargeable Li-O2batteries has proven difficult. The reaction paths leading to the final Li2O2discharge products can be greatly affected by the operating conditions or environment, which often results in major side reactions. Recent research findings have begun to reveal how the reaction paths may be affected by the surrounding conditions and to uncover the factors contributing to the difficulty in achieving the reactions of lithium and oxygen. This progress report describes the current state of understanding of the electrode reaction mechanisms in Li-O2batteries; the factors that affect reaction pathways; and the effect of cell components such as solvents, salts, additives, and catalysts on the discharge product and its decomposition during charging. This comprehensive review of the recent progress in understanding the reaction chemistry of the Li-O2system will serve as guidelines for future research and aid in the development of reliable high-energy-density rechargeable Li-O2batteries.
- Published
- 2017
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5. Tailoring Lithium Horizontal Deposition for Long-Lasting High-Loading NCA (≥5 mA h cm -2 )||Lithium-Metal Full Cells in Carbonate Electrolytes.
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Ku E, Yang HS, Lee HG, Lee H, Jeon B, Hong SU, Hong S, Lim HD, Park JH, Kim JH, Choi J, and Lee BS
- Abstract
We report a design for a synergistic lithium (Li) metal hosting layer for high-loading Li(Ni,Co,Al)O
2 (NCA) (≥5 mA h cm-2 )||Li-metal full cells in carbonate electrolytes. Based on density functional theory calculations, the hosting layer was designed as a three-dimensional silver/carbon composite nanofiber (Ag/CNF) network with high Li affinity and a platinum (Pt)-coated polypropylene separator with low Li affinity. This design enabled the tailoring of horizontal Li deposition on the Ag/CNF hosting layer. The Li deposition behavior modulated by the hosting layer was thoroughly examined based on the initial Li deposition and cycling behaviors of the Li||Li symmetric cell configuration. Cryogenic focused-ion beam cross-sectional images of the cycled Li anodes clearly demonstrated that dense lithium deposition was enabled by the synergistic hosting layer high-loading NCA (≥5 mA h cm-2 )||Li-metal full cells. When the hosting layer was used, the average cycling performance improved by 78.27% under various cycling conditions. Our work demonstrates that the synergistic hosting layer design is a fruitful pathway to accelerate the commercialization of high-energy-density Li-metal batteries in carbonate electrolytes.- Published
- 2024
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6. The chemokine receptor CCR8 is not a high-affinity receptor for the human chemokine CCL18.
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Hussain K, Lim HD, Devkota SR, Kemp-Harper BK, Lane JR, Canals M, Pease JE, and Stone MJ
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- Animals, Cricetinae, Humans, Mice, Cell Line, Cell Movement, CHO Cells, Cyclic AMP metabolism, Chemokines, CC metabolism, Chemokines, CC genetics, Cricetulus, Receptors, CCR8 metabolism, Receptors, CCR8 genetics
- Abstract
The primate-specific chemokine CCL18 is a potent chemoattractant for T cells and is expressed at elevated levels in several inflammatory diseases. However, the cognate receptor for CCL18 remains unconfirmed. Here, we describe attempts to validate a previous report that the chemokine receptor CCR8 is the human CCL18 receptor (Islam et al. J Exp Med. 2013, 210:1889-98). Two mouse pre-B cell lines (4DE4 and L1.2) exogenously expressing CCR8 exhibited robust migration in response to the known CCR8 ligand CCL1 but not to CCL18. Similarly, CCL1 but not CCL18 induced internalization of CCR8 on 4DE4 cells. CCR8 expressed on Chinese hamster ovarian (CHO) cells mediated robust G protein activation, inhibition of cAMP synthesis and β-arrestin2 recruitment in response to CCL1 but not CCL18. Several N- and C-terminal variants of CCL18 also failed to stimulate CCR8 activation. On the other hand, and as previously reported, CCL18 inhibited CCL11-stimulated migration of 4DE4 cells expressing the receptor CCR3. These data suggest that CCR8, at least in the absence of unidentified cofactors, does not function as a high affinity receptor for CCL18., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Hussain et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2024
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7. High-Power and Large-Area Anodes for Safe Lithium-Metal Batteries.
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Ha S, Park JY, Huh SH, Yu SH, Kwak JH, Park J, Lim HD, Ahn DJ, Jin HJ, Lim HK, Yang SJ, and Yun YS
- Abstract
The lithium deposited via the complex electrochemical heterogeneous lithium deposition reaction (LDR) process on a lithium foil-based anode (LFA) forms a high-aspect-ratio shape whenever the reaction kinetics reach its limit, threatening battery safety. Thereby, a research strategy that boosts the LDR kinetics is needed to construct a high-power and safe lithium metal anode. In this study, the kinetic limitations of the LDR process on LFA are elucidated through operando and ex situ observations using in-depth electrochemical analyses. In addition, ultra-thin (≈0.5 µm) and high modulus (≥19 GPa) double-walled carbon nanotube (DWNT) membranes with different surface properties are designed to catalyze high-safety LDRs. The oxygen-functionalized DWNT membranes introduced on the LFA top surface simultaneously induce multitudinous lithium nuclei, leading to film-like lithium deposition even at a high current density of 20 mA cm
-2 . More importantly, the layer-by-layer assembly of the oxygen-functionalized and pristine DWNT membranes results in different surface energies between the top and bottom surfaces, enabling selective surface LDRs underneath the high-modulus bilayer membranes. The protective LDR on the bilayer-covered LFA guarantees an invulnerable cycling process in large-area pouch cells at high current densities for more than 1000 cycles, demonstrating the practicability of LFA in a conventional liquid electrolyte system., (© 2024 Wiley‐VCH GmbH.)- Published
- 2024
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8. Reversible Mg-Metal Batteries Enabled by a Ga-Rich Protective Layer through One-Step Interface Engineering.
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Shin S, Kwak JH, Oh SH, Kim HS, Yu SH, and Lim HD
- Abstract
Practical applications of Mg-metal batteries (MMBs) have been plagued by a critical bottleneck─the formation of a native oxide layer on the Mg-metal interface─which inevitably limits the use of conventional nontoxic electrolytes. The major aim of this work was to propose a simple and effective way to reversibly operate MMBs in combination with Mg(TFSI)
2 -diglyme electrolyte by forming a Ga-rich protective layer on the Mg metal (GPL@Mg). Mg metal was carefully reacted with a GaCl3 solution to trigger a galvanic replacement reaction between Ga3+ and Mg, resulting in the layering of a stable and ion-conducting Ga-rich protective film while preventing the formation of a native insulating layer. Various characterization tools were applied to analyze GPL@Mg, and it was demonstrated to contain inorganic-rich compounds (MgCO3 , Mg(OH)2 , MgCl2 , Ga2 O3 , GaCl3 , and MgO) roughly in a double-layered structure. The artificial GPL on Mg was effective in greatly reducing the high polarization for Mg plating and stripping in diglyme-based electrolyte, and the stable cycling was maintained for over 200 h. The one-step process suggested in this work offers insights into exploring a cost-effective approach to cover the Mg-metal surface with an ion-conducting artificial layer, which will help to practically advance MMBs.- Published
- 2023
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9. WFS1 autosomal dominant variants linked with hearing loss: update on structural analysis and cochlear implant outcome.
- Author
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Lim HD, Lee SM, Yun YJ, Lee DH, Lee JH, Oh SH, and Lee SY
- Subjects
- Humans, Pedigree, Wolfram Syndrome complications, Wolfram Syndrome genetics, Wolfram Syndrome pathology, Cochlear Implants, Cochlear Implantation, Hearing Loss genetics, Deafness
- Abstract
Background: Wolfram syndrome type 1 gene (WFS1), which encodes a transmembrane structural protein (wolframin), is essential for several biological processes, including proper inner ear function. Unlike the recessively inherited Wolfram syndrome, WFS1 heterozygous variants cause DFNA6/14/38 and wolfram-like syndrome, characterized by autosomal dominant nonsyndromic hearing loss, optic atrophy, and diabetes mellitus. Here, we identified two WFS1 heterozygous variants in three DFNA6/14/38 families using exome sequencing. We reveal the pathogenicity of the WFS1 variants based on three-dimensional (3D) modeling and structural analysis. Furthermore, we present cochlear implantation (CI) outcomes in WFS1-associated DFNA6/14/38 and suggest a genotype-phenotype correlation based on our results and a systematic review., Methods: We performed molecular genetic test and evaluated clinical phenotypes of three WFS1-associated DFNA6/14/38 families. A putative WFS1-NCS1 interaction model was generated, and the impacts of WFS1 variants on stability were predicted by comparing intramolecular interactions. A total of 62 WFS1 variants associated with DFNA6/14/38 were included in a systematic review., Results: One variant is a known mutational hotspot variant in the endoplasmic reticulum (ER)-luminal domain WFS1(NM_006005.3) (c.2051 C > T:p.Ala684Val), and the other is a novel frameshift variant in transmembrane domain 6 (c.1544_1545insA:p.Phe515LeufsTer28). The two variants were pathogenic, based on the ACMG/AMP guidelines. Three-dimensional modeling and structural analysis show that non-polar, hydrophobic substitution of Ala684 (p.Ala684Val) destabilizes the alpha helix and contributes to the loss of WFS1-NCS1 interaction. Also, the p.Phe515LeufsTer28 variant truncates transmembrane domain 7-9 and the ER-luminal domain, possibly impairing membrane localization and C-terminal signal transduction. The systematic review demonstrates favorable outcomes of CI. Remarkably, p.Ala684Val in WFS1 is associated with early-onset severe-to-profound deafness, revealing a strong candidate variant for CI., Conclusions: We expanded the genotypic spectrum of WFS1 heterozygous variants underlying DFNA6/14/38 and revealed the pathogenicity of mutant WFS1, providing a theoretical basis for WFS1-NCS1 interactions. We presented a range of phenotypic traits for WFS1 heterozygous variants and demonstrated favorable functional CI outcomes, proposing p.Ala684Val a strong potential marker for CI candidates., (© 2023. The Author(s).)
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- 2023
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10. Revisiting Lithium- and Sodium-Ion Storage in Hard Carbon Anodes.
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Kim H, Hyun JC, Kim DH, Kwak JH, Lee JB, Moon JH, Choi J, Lim HD, Yang SJ, Jin HM, Ahn DJ, Kang K, Jin HJ, Lim HK, and Yun YS
- Abstract
The galvanostatic lithiation/sodiation voltage profiles of hard carbon anodes are simple, with a sloping drop followed by a plateau. However, a precise understanding of the corresponding redox sites and storage mechanisms is still elusive, which hinders further development in commercial applications. Here, a comprehensive comparison of the lithium- and sodium-ion storage behaviors of hard carbon is conducted, yielding the following key findings: 1) the sloping voltage section is presented by the lithium-ion intercalation in the graphitic lattices of hard carbons, whereas it mainly arises from the chemisorption of sodium ions on their inner surfaces constituting closed pores, even if the graphitic lattices are unoccupied; 2) the redox sites for the plateau capacities are the same as those for the closed pores regardless of the alkali ions; 3) the sodiation plateau capacities are mostly determined by the volume of the available closed pore, whereas the lithiation plateau capacities are primarily affected by the intercalation propensity; and 4) the intercalation preference and the plateau capacity have an inverse correlation. These findings from extensive characterizations and theoretical investigations provide a relatively clear elucidation of the electrochemical footprint of hard carbon anodes in relation to the redox mechanisms and storage sites for lithium and sodium ions, thereby providing a more rational design strategy for constructing better hard carbon anodes., (© 2023 Wiley-VCH GmbH.)
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- 2023
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11. Identification and Characterization of ML321: A Novel and Highly Selective D 2 Dopamine Receptor Antagonist with Efficacy in Animal Models That Predict Atypical Antipsychotic Activity.
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Free RB, Nilson AN, Boldizsar NM, Doyle TB, Rodriguiz RM, Pogorelov VM, Machino M, Lee KH, Bertz JW, Xu J, Lim HD, Dulcey AE, Mach RH, Woods JH, Lane JR, Shi L, Marugan JJ, Wetsel WC, and Sibley DR
- Abstract
We have developed and characterized a novel D2R antagonist with exceptional GPCR selectivity - ML321. In functional profiling screens of 168 different GPCRs, ML321 showed little activity beyond potent inhibition of the D2R and to a lesser extent the D3R, demonstrating excellent receptor selectivity. The D2R selectivity of ML321 may be related to the fact that, unlike other monoaminergic ligands, ML321 lacks a positively charged amine group and adopts a unique binding pose within the orthosteric binding site of the D2R. PET imaging studies in non-human primates demonstrated that ML321 penetrates the CNS and occupies the D2R in a dose-dependent manner. Behavioral paradigms in rats demonstrate that ML321 can selectively antagonize a D2R-mediated response (hypothermia) while not affecting a D3R-mediated response (yawning) using the same dose of drug, thus indicating exceptional in vivo selectivity. We also investigated the effects of ML321 in animal models that are predictive of antipsychotic efficacy in humans. We found that ML321 attenuates both amphetamine- and phencyclidine-induced locomotor activity and restored pre-pulse inhibition (PPI) of acoustic startle in a dose-dependent manner. Surprisingly, using doses that were maximally effective in both the locomotor and PPI studies, ML321 was relatively ineffective in promoting catalepsy. Kinetic studies revealed that ML321 exhibits slow-on and fast-off receptor binding rates, similar to those observed with atypical antipsychotics with reduced extrapyramidal side effects. Taken together, these observations suggest that ML321, or a derivative thereof, may exhibit ″atypical″ antipsychotic activity in humans with significantly fewer side effects than observed with the currently FDA-approved D2R antagonists., Competing Interests: The authors declare no competing financial interest., (© 2022 American Chemical Society.)
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- 2022
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12. Structure-guided engineering of tick evasins for targeting chemokines in inflammatory diseases.
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Bhusal RP, Aryal P, Devkota SR, Pokhrel R, Gunzburg MJ, Foster SR, Lim HD, Payne RJ, Wilce MCJ, and Stone MJ
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- Animals, Arthropod Proteins metabolism, Protein Binding, Protein Conformation, Receptors, Chemokine metabolism, Arthropod Proteins chemistry, Chemokines metabolism, Inflammation metabolism, Protein Engineering, Ticks metabolism
- Abstract
As natural chemokine inhibitors, evasin proteins produced in tick saliva are potential therapeutic agents for numerous inflammatory diseases. Engineering evasins to block the desired chemokines and avoid off-target side effects requires structural understanding of their target selectivity. Structures of the class A evasin EVA-P974 bound to human CC chemokine ligands 7 and 17 (CCL7 and CCL17) and to a CCL8-CCL7 chimera reveal that the specificity of class A evasins for chemokines of the CC subfamily is defined by conserved, rigid backbone-backbone interactions, whereas the preference for a subset of CC chemokines is controlled by side-chain interactions at four hotspots in flexible structural elements. Hotspot mutations alter target preference, enabling inhibition of selected chemokines. The structure of an engineered EVA-P974 bound to CCL2 reveals an underlying molecular mechanism of EVA-P974 target preference. These results provide a structure-based framework for engineering evasins as targeted antiinflammatory therapeutics., Competing Interests: The authors declare no competing interest., (Copyright © 2022 the Author(s). Published by PNAS.)
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- 2022
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13. Self-Constructed Intimate Interface on a Silicon Anode Enabled by a Phase-Convertible Electrolyte for Lithium-Ion Batteries.
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Bintang HM, Lee S, Kim JT, Jung HG, and Lim HD
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Promising high-capacity anodes of Si-based materials suffer from large volume expansions, thereby limiting their practical applications, especially in combination with safe inorganic solid electrolytes. Here, to achieve a high level of safety by applying Si anodes, we introduced a quasi-solid-state succinonitrile-based electrolyte (QS-SCN) that enables the practical application of the anode with long-term cycling performance. By exploiting the unique phase-convertible property of QS-SCN, the Si electrode was successfully impregnated with the liquid-state electrolyte above its melting temperature, and a simple cooling process was then used to form a quasi-solid-state Li-Si cell. Additionally, through a precycling process, the formation of a stable and rigid solid-electrolyte interphase (SEI) was induced, and the intimate contacts between the QS-SCN and Si particles were preserved. The soft QS-SCN played an important role as a buffer in the large volume expansions while maintaining favorable interface contacts, and the formation of the SEI layers contributed to the reversible lithiation and delithiation in the Si particles. As a result, the quasi-solid-state Li-Si cell fabricated with QS-SCN exhibited significantly improved capacity retention compared with an all-solid-state cell.
- Published
- 2022
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14. Pollutant dispersion by tall buildings: laboratory experiments and Large-Eddy Simulation.
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Lim HD, Hertwig D, Grylls T, Gough H, Reeuwijk MV, Grimmond S, and Vanderwel C
- Abstract
Abstract: Pollutant dispersion by a tall-building cluster within a low-rise neighbourhood of Beijing is investigated using both full-scale Large-Eddy Simulation and water flume experiments at 1:2400 model-to-full scale with Particle Image Velocimetry and Planar Laser-Induced Fluorescence. The Large-Eddy Simulation and flume results of this realistic test case agree remarkably well despite differences in the inflow conditions and scale. Tall buildings have strong influence on the local flow and the development of the rooftop shear layer which dominates vertical momentum and scalar fluxes. Additional measurements using tall-buildings-only models at both 1:2400 and 1:4800 scales indicates the rooftop shear layer is insensitive to the scale. The relatively thicker incoming boundary layer affects the Reynolds stresses, the relative size of the pollutant source affects the concentration statistics and the relative laser-sheet thickness affects the spatially averaged results of the measured flow field. Low-rise buildings around the tall building cluster cause minor but non-negligible offsets in the peak magnitude and vertical location, and have a similar influence on the velocity and concentration statistics as the scale choice. These observations are generally applicable to pollutant dispersion of realistic tall building clusters in cities. The consistency between simulations and water tunnel experiments indicates the suitability of both methodologies., (© The Author(s) 2022.)
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- 2022
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15. Elucidating and Mitigating High-Voltage Degradation Cascades in Cobalt-Free LiNiO 2 Lithium-Ion Battery Cathodes.
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Park KY, Zhu Y, Torres-Castanedo CG, Jung HJ, Luu NS, Kahvecioglu O, Yoo Y, Seo JT, Downing JR, Lim HD, Bedzyk MJ, Wolverton C, and Hersam MC
- Abstract
LiNiO
2 (LNO) is a promising cathode material for next-generation Li-ion batteries due to its exceptionally high capacity and cobalt-free composition that enables more sustainable and ethical large-scale manufacturing. However, its poor cycle life at high operating voltages over 4.1 V impedes its practical use, thus motivating efforts to elucidate and mitigate LiNiO2 degradation mechanisms at high states of charge. Here, a multiscale exploration of high-voltage degradation cascades associated with oxygen stacking chemistry in cobalt-free LiNiO2 , is presented. Lattice oxygen loss is found to play a critical role in the local O3-O1 stacking transition at high states of charge, which subsequently leads to Ni-ion migration and irreversible stacking faults during cycling. This undesirable atomic-scale structural evolution accelerates microscale electrochemical creep, cracking, and even bending of layers, ultimately resulting in macroscopic mechanical degradation of LNO particles. By employing a graphene-based hermetic surface coating, oxygen loss is attenuated in LNO at high states of charge, which suppresses the initiation of the degradation cascade and thus substantially improves the high-voltage capacity retention of LNO. Overall, this study provides mechanistic insight into the high-voltage degradation of LNO, which will inform ongoing efforts to employ cobalt-free cathodes in Li-ion battery technology., (© 2021 Wiley-VCH GmbH.)- Published
- 2022
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16. Growth Suppression of a Gingivitis and Skin Pathogen Cutibacterium ( Propionibacterium ) acnes by Medicinal Plant Extracts.
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Choi HA, Ahn SO, Lim HD, and Kim GJ
- Abstract
Propionibacterium acnes , newly reclassified as Cutibacterium acnes , is an anaerobic Gram-positive bacterium causing acne, found mainly on the skin. In addition, P. acnes is responsible for inflammation of the gums (gingivitis) and blood vessels, consequently leading to various diseases in the human body. In recent years, the evolution of microorganisms, such as P. acnes, that have become resistant to many commercial antibiotics due to the widespread use of antimicrobial drugs in the treatment of infectious diseases has emerged as a major clinical problem. We here analyzed the potential use of 37 medicinal plant extracts as plausible candidates for treating P. acnes , in terms of total phenolic and flavonoid contents, antioxidants scavenging and antimicrobial activity. Consequently, methanol extracts from 14 medicinal plants showed promising antimicrobial activities against P . acnes . In particular, as the extracts from Chrysosplenium flagelliferum F. and Thuja orientalis L. exhibited distinct antimicrobial activities in both the broth dilution and disc diffusion assay, they could be effectively used as active ingredients for preventing or treating inflammatory periodontal diseases, such as periodontitis.
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- 2021
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17. Increase your Confidence in Opioid Prescribing: Marketing Messages in Continuing Medical Education Activities on ER/LA Opioids.
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Goodwin B, Lim HD, Butler J, Paglia D, Dempsey MT, O Connor B, and Fugh-Berman A
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- Analgesics, Opioid therapeutic use, Education, Medical, Continuing, Humans, Marketing, Practice Patterns, Physicians', Chronic Pain drug therapy, Opioid-Related Disorders drug therapy, Opioid-Related Disorders prevention & control
- Abstract
Background: Overprescription of opioids has fueled an epidemic of addiction and overdose deaths. The FDA required manufacturers of extended-release/long-acting (ER/LA) opioids to fund continuing medical education (CME) on opioids as part of a Risk Evaluation and Mitigation Strategy (REMS)., Objectives: We sought to determine whether industry-funded REMS on long-acting opioids were consistent with the FDA's goal to reduce serious, adverse outcomes resulting from inappropriate prescribing, misuse, and abuse., Study Design: In 2018, we analyzed all internet-based REMS CME activities funded by the REMS Program Companies (RPC), a consortium of ER/LA opioid manufacturers., Methods: We utilized systematic narrative thematic analysis, an inductive approach that allows for mapping of concepts and meanings across a body of data by identifying, recording, analyzing, and refining key narrative points, called "themes". Authors viewed all REMS activities multiple times., Results: Ten themes were identified, all of which were at least somewhat incongruent with federal guidelines and their goals: 1. Chronic pain is a common, under-treated problem. 2.Chronic pain is a chronic disease.3.Opioids are an appropriate treatment for chronic pain. 4.LAs are more appropriate than immediate-release (IR) opioids for chronic pain. 5.Tolerance is normal, expected, and beneficial. 6. Opioid rotation" can maximize analgesia and minimize adverse effects.7. There is no population for whom opioids are absolutely contraindicated or inappropriate. 8. Screening and monitoring tools are effective for preventing opioid-related problems. 9. Opioid related adverse effects, such as respiratory depression and addiction, are due only to misuse and abuse. Addiction, overdose, and death are due to street drugs such as heroin and fentanyl, not prescription opioids.Themes and statements repeated in these activities were inconsistent with current medical knowledge, evidence-based federal guidelines, and FDA goals., Limitations: We evaluated only online, not live, CME. We also did not evaluate individual conflicts of interest of faculty., Conclusions: Industry-funded REMS-compliant CME on opioids contain messages that misrepresent scientific evidence and may foster overprescribing of opioids.
- Published
- 2021
18. Soluble Expression and Efficient Purification of Recombinant Class I Hydrophobin DewA.
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Ahn SO, Lim HD, You SH, Cheong DE, and Kim GJ
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- Aspergillus nidulans growth & development, Fungal Proteins genetics, Hydrophobic and Hydrophilic Interactions, Recombinant Proteins genetics, Surface Properties, Aspergillus nidulans metabolism, Fungal Proteins isolation & purification, Fungal Proteins metabolism, Recombinant Proteins isolation & purification, Recombinant Proteins metabolism
- Abstract
Hydrophobins are small proteins (<20 kDa) with an amphipathic tertiary structure that are secreted by various filamentous fungi. Their amphipathic properties provide surfactant-like activity, leading to the formation of robust amphipathic layers at hydrophilic-hydrophobic interfaces, which make them useful for a wide variety of industrial fields spanning protein immobilization to surface functionalization. However, the industrial use of recombinant hydrophobins has been hampered due to low yield from inclusion bodies owing to the complicated process, including an auxiliary refolding step. Herein, we report the soluble expression of a recombinant class I hydrophobin DewA originating from Aspergillus nidulans, and its efficient purification from recombinant Escherichia coli . Soluble expression of the recombinant hydrophobin DewA was achieved by a tagging strategy using a systematically designed expression tag (ramp tag) that was fused to the N-terminus of DewA lacking the innate signal sequence. Highly expressed recombinant hydrophobin DewA in a soluble form was efficiently purified by a modified aqueous two-phase separation technique using isopropyl alcohol. Our approach for expression and purification of the recombinant hydrophobin DewA in E. coli shed light on the industrial production of hydrophobins from prokaryotic hosts.
- Published
- 2021
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19. Systematic Assessment of Chemokine Signaling at Chemokine Receptors CCR4, CCR7 and CCR10.
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Lim HD, Lane JR, Canals M, and Stone MJ
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- Enzyme-Linked Immunosorbent Assay, Humans, Receptors, CCR genetics, Receptors, CCR metabolism, Receptors, CCR10 genetics, Receptors, CCR4 genetics, Receptors, CCR7 genetics, Signal Transduction genetics, Signal Transduction physiology, Chemokines metabolism, Receptors, CCR10 metabolism, Receptors, CCR4 metabolism, Receptors, CCR7 metabolism
- Abstract
Chemokines interact with chemokine receptors in a promiscuous network, such that each receptor can be activated by multiple chemokines. Moreover, different chemokines have been reported to preferentially activate different signalling pathways via the same receptor, a phenomenon known as biased agonism. The human CC chemokine receptors (CCRs) CCR4, CCR7 and CCR10 play important roles in T cell trafficking and have been reported to display biased agonism. To systematically characterize these effects, we analysed G protein- and β-arrestin-mediated signal transduction resulting from stimulation of these receptors by each of their cognate chemokine ligands within the same cellular background. Although the chemokines did not elicit ligand-biased agonism, the three receptors exhibited different arrays of signaling outcomes. Stimulation of CCR4 by either CC chemokine ligand 17 (CCL17) or CCL22 induced β-arrestin recruitment but not G protein-mediated signaling, suggesting that CCR4 has the potential to act as a scavenger receptor. At CCR7, both CCL19 and CCL21 stimulated G protein signaling and β-arrestin recruitment, with CCL19 consistently displaying higher potency. At CCR10, CCL27 and CCL28(4-108) stimulated both G protein signaling and β-arrestin recruitment, whereas CCL28(1-108) was inactive, suggesting that CCL28(4-108) is the biologically relevant form of this chemokine. These comparisons emphasize the intrinsic abilities of different receptors to couple with different downstream signaling pathways. Comparison of these results with previous studies indicates that differential agonism at these receptors may be highly dependent on the cellular context.
- Published
- 2021
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20. Acupuncture stimulation attenuates TNF-α production via vagal modulation in the concanavalin A model of hepatitis.
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Lim HD, Kim KJ, Jo BG, Park JY, and Namgung U
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- Acupuncture Points, Animals, Hepatitis genetics, Humans, Male, Mice, Mice, Inbred BALB C, Rats, Rats, Sprague-Dawley, Tumor Necrosis Factor-alpha genetics, Acupuncture Therapy, Concanavalin A metabolism, Hepatitis metabolism, Hepatitis therapy, Tumor Necrosis Factor-alpha metabolism, Vagus Nerve metabolism
- Abstract
Background: A growing body of evidence shows that neuronal activity is involved in modulating the efficacy of acupuncture therapy. However, it has been seldom investigated whether neuronal activity following acupuncture stimulation is effective at regulating hepatic inflammation., Objective: Using the concanavalin A (ConA) model of hepatitis, we investigated the regulation of inflammatory cytokine tumor necrosis factor (TNF)-α in the liver tissue and the blood after acupuncture stimulation at ST36., Methods: Mice were subjected to ConA injection, acupuncture stimulation at ST36 by manual acupuncture (MA) or electroacupuncture (EA) procedures, and vagotomy (VNX). Liver tissue and blood were collected for TNF-α analysis. TNF-α mRNA was analyzed by real-time polymerase chain reaction (PCR), and TNF-α, CD11b, CD68, and Erk1/2 proteins were analyzed by Western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assay., Results: TNF-α mRNA and protein were induced in CD11b-positive hepatic cells and the plasma at 6-24 h after ConA injection. The application of MA or EA was very effective at attenuating the production of TNF-α. Anti-inflammatory effects of acupuncture were greatly suppressed by VNX in ConA-injected animals, suggesting the requirement of vagus nerve activity in acupuncture-mediated anti-inflammatory responses. Electrical stimulation of the sciatic nerve (SNS) resulted in an anti-inflammatory effect similar to acupuncture stimulation. In parallel with TNF-α, production of phospho-Erk1/2, which was induced in the liver tissue, was downregulated by MA and EA in liver cells., Conclusion: The regulatory effects of acupuncture stimulation on inflammatory responses in the liver may be modulated through the activation of the vagus nerve pathway.
- Published
- 2020
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21. Hierarchically Nanoporous 3D Assembly Composed of Functionalized Onion-Like Graphitic Carbon Nanospheres for Anode-Minimized Li Metal Batteries.
- Author
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Ha S, Hyun JC, Kwak JH, Lim HD, and Yun YS
- Abstract
Despite the recent attention for Li metal anode (LMA) with high theoretical specific capacity of ≈3860 mA h g
-1 , it suffers from not enough practical energy densities and safety concerns originating from the excessive metal load, which is essential to compensate for the loss of Li sources resulting from their poor coulombic efficiencies (CEs). Therefore, the development of high-performance LMA is needed to realize anode-minimized Li metal batteries (LMBs). In this study, high-performance LMAs are produced by introducing a hierarchically nanoporous assembly (HNA) composed of functionalized onion-like graphitic carbon building blocks, several nanometers in diameter, as a catalytic scaffold for Li-metal storage. The HNA-based electrodes lead to a high Li ion concentration in the nanoporous structure, showing a high CE of ≈99.1%, high rate capability of 12 mA cm-2 , and a stable cycling behavior of more than 750 cycles. In addition, anode-minimized LMBs are achieved using a HNA that has limited Li content (≈0.13 mg cm-2 ), corresponding to 6.5% of the cathode material (commercial NCM622 (≈2 mg cm-2 )). The LMBs demonstrate a feasible electrochemical performance with high energy and power densities of ≈510 Wh kgelectrode -1 and ≈2760 W kgelectrode -1 , respectively, for more than 100 cycles., (© 2020 Wiley-VCH GmbH.)- Published
- 2020
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22. Enough Is Enough.
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Lim HD
- Subjects
- Child, Humans, Male, Crime Victims, Firearms, Gun Violence
- Abstract
In this cartoon, a guilt-ridden and heavily scarred surgeon prepares to self-flagellate to atone for his team's failed attempts to save the life of an innocent child victim of a mass shooting. One of his nurses, carrying an assault rifle modified to serve as his whip, attempts to stop him by reminding him that the blame is not his to bear. We in the field of medicine can and must do more for our patients than simply treating their wounds and consoling their families and loved ones after tragic, senseless losses. Solving the gun violence epidemic won't be easy, but we must try., (© 2020 American Medical Association. All Rights Reserved.)
- Published
- 2020
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23. Low intrinsic efficacy for G protein activation can explain the improved side effect profiles of new opioid agonists.
- Author
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Gillis A, Gondin AB, Kliewer A, Sanchez J, Lim HD, Alamein C, Manandhar P, Santiago M, Fritzwanker S, Schmiedel F, Katte TA, Reekie T, Grimsey NL, Kassiou M, Kellam B, Krasel C, Halls ML, Connor M, Lane JR, Schulz S, Christie MJ, and Canals M
- Subjects
- HEK293 Cells, Humans, Receptors, Opioid, mu genetics, Receptors, Opioid, mu metabolism, Urea adverse effects, Urea chemistry, Urea pharmacology, beta-Arrestins genetics, beta-Arrestins metabolism, Benzimidazoles adverse effects, Benzimidazoles chemistry, Benzimidazoles pharmacology, Piperidines adverse effects, Piperidines chemistry, Piperidines pharmacology, Receptors, Opioid, mu agonists, Spiro Compounds adverse effects, Spiro Compounds chemistry, Spiro Compounds pharmacology, Thiophenes adverse effects, Thiophenes chemistry, Thiophenes pharmacology, Urea analogs & derivatives
- Abstract
Biased agonism at G protein-coupled receptors describes the phenomenon whereby some drugs can activate some downstream signaling activities to the relative exclusion of others. Descriptions of biased agonism focusing on the differential engagement of G proteins versus β-arrestins are commonly limited by the small response windows obtained in pathways that are not amplified or are less effectively coupled to receptor engagement, such as β-arrestin recruitment. At the μ-opioid receptor (MOR), G protein-biased ligands have been proposed to induce less constipation and respiratory depressant side effects than opioids commonly used to treat pain. However, it is unclear whether these improved safety profiles are due to a reduction in β-arrestin-mediated signaling or, alternatively, to their low intrinsic efficacy in all signaling pathways. Here, we systematically evaluated the most recent and promising MOR-biased ligands and assessed their pharmacological profile against existing opioid analgesics in assays not confounded by limited signal windows. We found that oliceridine, PZM21, and SR-17018 had low intrinsic efficacy. We also demonstrated a strong correlation between measures of efficacy for receptor activation, G protein coupling, and β-arrestin recruitment for all tested ligands. By measuring the antinociceptive and respiratory depressant effects of these ligands, we showed that the low intrinsic efficacy of opioid ligands can explain an improved side effect profile. Our results suggest a possible alternative mechanism underlying the improved therapeutic windows described for new opioid ligands, which should be taken into account for future descriptions of ligand action at this important therapeutic target., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2020
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24. Distinct inactive conformations of the dopamine D2 and D3 receptors correspond to different extents of inverse agonism.
- Author
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Lane JR, Abramyan AM, Adhikari P, Keen AC, Lee KH, Sanchez J, Verma RK, Lim HD, Yano H, Javitch JA, and Shi L
- Subjects
- Binding Sites, Drug Discovery, Molecular Dynamics Simulation, Protein Binding, Protein Conformation, Risperidone chemistry, Risperidone metabolism, Salicylamides chemistry, Salicylamides metabolism, Dopamine Agonists chemistry, Dopamine Agonists metabolism, Dopamine Antagonists chemistry, Dopamine Antagonists metabolism, Receptors, Dopamine D2 chemistry, Receptors, Dopamine D2 metabolism, Receptors, Dopamine D3 chemistry, Receptors, Dopamine D3 metabolism
- Abstract
By analyzing and simulating inactive conformations of the highly homologous dopamine D
2 and D3 receptors (D2 R and D3 R), we find that eticlopride binds D2 R in a pose very similar to that in the D3 R/eticlopride structure but incompatible with the D2 R/risperidone structure. In addition, risperidone occupies a sub-pocket near the Na+ binding site, whereas eticlopride does not. Based on these findings and our experimental results, we propose that the divergent receptor conformations stabilized by Na+ -sensitive eticlopride and Na+ -insensitive risperidone correspond to different degrees of inverse agonism. Moreover, our simulations reveal that the extracellular loops are highly dynamic, with spontaneous transitions of extracellular loop 2 from the helical conformation in the D2 R/risperidone structure to an extended conformation similar to that in the D3 R/eticlopride structure. Our results reveal previously unappreciated diversity and dynamics in the inactive conformations of D2 R. These findings are critical for rational drug discovery, as limiting a virtual screen to a single conformation will miss relevant ligands., Competing Interests: JL, AA, PA, AK, KL, JS, RV, HL, HY, JJ, LS No competing interests declared- Published
- 2020
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25. Presodiation Strategies and Their Effect on Electrode-Electrolyte Interphases for High-Performance Electrodes for Sodium-Ion Batteries.
- Author
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Moeez I, Jung HG, Lim HD, and Chung KY
- Abstract
Most active materials for sodium-ion batteries suffer from the problem of low-energy efficiency in the first cycle because of the loss of active sodium ions consumed for the formation of a solid electrolyte interface. To make up for the lost sodium ion, presodiation treatments have been applied, which are effective ways to mitigate the low initial efficiency. Here, we developed a direct-contact method to achieve the presodiation for cathode and anode electrodes and demonstrated the enhanced Coulombic efficiency of the first cycle with improved cyclability and reversible capacity. Moreover, we proved the formation of a thick passivation layer at the cathode-electrolyte interface during the presodiation process; this contributes to the improved cycle stability by preventing the dissolution of the active material and its deposition on the anode surface. The direct-contact method is a simple and cost-effective way to complete presodiation, and this simple process will be widely applicable for practical battery manufacturing.
- Published
- 2019
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26. Magnesiophilic Graphitic Carbon Nanosubstrate for Highly Efficient and Fast-Rechargeable Mg Metal Batteries.
- Author
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Lim HD, Kim DH, Park S, Lee ME, Jin HJ, Yu S, Oh SH, and Yun YS
- Abstract
The high volumetric energy density of rechargeable Mg batteries (RMBs) gives them a competitive advantage over current Li ion batteries, which originates from the high volumetric capacity (∼3833 mA h cm
-3 ) of bivalent Mg metal anodes (MMAs). On the other hand, despite their importance, there are few reports on research strategies to improve the electrochemical performance of MMAs. This paper reports that catalytic carbon nanosubstrates rather than metal-based substrates, such as Mo, Cu, and stainless steel, are essential in MMAs to improve the electrochemical performance of RMBs. In particular, three-dimensional macroporous graphitic carbon nanosubstrates (GC-NSs) with high electrical conductivities can accommodate Mg metal with significantly higher rate capabilities and Coulombic efficiencies than metal substrates, resulting in a more stable and longer-term cycling performance over 1000 cycles. In addition, while metal-based substrates suffered from undesirable Mg peeling-off, homogeneous Mg metal deposition is well-guided in GC-NSs owing to the better affinity of the Mg2+ ion. These results are supported by density functional theory calculations and ex-situ characterization.- Published
- 2019
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27. Molecular Determinants of the Intrinsic Efficacy of the Antipsychotic Aripiprazole.
- Author
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Klein Herenbrink C, Verma R, Lim HD, Kopinathan A, Keen A, Shonberg J, Draper-Joyce CJ, Scammells PJ, Christopoulos A, Javitch JA, Capuano B, Shi L, and Lane JR
- Subjects
- Antipsychotic Agents chemistry, Aripiprazole chemistry, Binding Sites, Dopamine chemistry, Dopamine metabolism, Dopamine Agonists chemistry, Indoles chemistry, Indoles metabolism, Ligands, Molecular Conformation, Molecular Dynamics Simulation, Mutagenesis, Site-Directed, Mutation, Receptors, Dopamine D2 chemistry, Receptors, Dopamine D2 genetics, Antipsychotic Agents metabolism, Aripiprazole metabolism, Dopamine Agonists metabolism, Receptors, Dopamine D2 metabolism
- Abstract
Partial agonists of the dopamine D
2 receptor (D2 R) have been developed to treat the symptoms of schizophrenia without causing the side effects elicited by antagonists. The receptor-ligand interactions that determine the intrinsic efficacy of such drugs, however, are poorly understood. Aripiprazole has an extended structure comprising a phenylpiperazine primary pharmacophore and a 1,2,3,4-tetrahydroquinolin-2-one secondary pharmacophore. We combined site-directed mutagenesis, analytical pharmacology, ligand fragments, and molecular dynamics simulations to identify the D2 R-aripiprazole interactions that contribute to affinity and efficacy. We reveal that an interaction between the secondary pharmacophore of aripiprazole and a secondary binding pocket defined by residues at the extracellular portions of transmembrane segments 1, 2, and 7 determines the intrinsic efficacy of aripiprazole. Our findings reveal a hitherto unappreciated mechanism for fine-tuning the intrinsic efficacy of D2 R agonists.- Published
- 2019
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28. Rapid and sensitive detection of NADPH via mBFP-mediated enhancement of its fluorescence.
- Author
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You SH, Lim HD, Cheong DE, Kim ES, and Kim GJ
- Subjects
- Catalysis, Cells, Cultured, Fluorescence, Glucosephosphate Dehydrogenase metabolism, Humans, Luminescent Proteins chemistry, Luminescent Proteins genetics, Metagenome, NADP metabolism, Oxidation-Reduction, Phosphotransferases metabolism, Sensitivity and Specificity, Time Factors, Luminescent Measurements methods, Luminescent Proteins metabolism, NADP analysis
- Abstract
The reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) functions as a reducing agent involved in many biosynthetic and antioxidant reactions in cells. Therefore, a lots of detection or assaying method of this cofactor are developed and used broadly in various research and application fields. These detection or assay tools, however, have often some problems, such as the low sensitivity, susceptibility to environmental interference and time-consuming pretreatment steps, remaining hurdle to successful quantification of NADPH or its derivatives accurately and immediately. Herein, we present a rapid (assay time < 30 s) and sensitive (detection limit < 2 pmol) detection method of NADPH using metagenome-derived blue fluorescent protein (mBFP), a protein capable of significantly enhancing NADPH fluorescence upon binding to this cofactor. Our method takes advantage of the high specificity of mBFP to NADPH and the immediate fluorescence enhancement upon the addition of mBFP to a solution of interest containing NADPH. We can apply this detection scheme to directly quantitative assessment of NADP(H)-dependent enzyme activities in-vitro, and further accessed to quantitative assay of other nicotine amide cofactors, such as NAD+ and NADH, by coupling assay using NAD(H) kinase. Thus, our method enabled us to quantitatively assess the activity of nicotinamide cofactor-associated enzymes in both bacterial and human cell lysates., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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29. A Thieno[2,3- d]pyrimidine Scaffold Is a Novel Negative Allosteric Modulator of the Dopamine D 2 Receptor.
- Author
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Fyfe TJ, Zarzycka B, Lim HD, Kellam B, Mistry SN, Katrich V, Scammells PJ, Lane JR, and Capuano B
- Subjects
- Allosteric Regulation, Allosteric Site, Animals, CHO Cells, Cricetinae, Cricetulus, Haloperidol chemistry, Haloperidol metabolism, Humans, Isotope Labeling, Kinetics, Molecular Conformation, Molecular Docking Simulation, Protein Binding, Pyrimidines chemical synthesis, Pyrimidines metabolism, Receptors, Dopamine D2 genetics, Receptors, Dopamine D2 metabolism, Structure-Activity Relationship, Tritium chemistry, Pyrimidines chemistry, Receptors, Dopamine D2 chemistry
- Abstract
Recently, a novel negative allosteric modulator (NAM) of the D
2 -like dopamine receptors 1 was identified through virtual ligand screening. This ligand comprises a thieno[2,3- d]pyrimidine scaffold that does not feature in known dopaminergic ligands. Herein, we provide pharmacological validation of an allosteric mode of action for 1, revealing that it is a NAM of dopamine efficacy and identify the structural determinants of this allostery. We find that key structural moieties are important for functional affinity and negative cooperativity, while functionalization of the thienopyrimidine at the 5- and 6-positions results in analogues with divergent cooperativity profiles. Successive compound iterations have yielded analogues exhibiting a 10-fold improvement in functional affinity, as well as enhanced negative cooperativity with dopamine affinity and efficacy. Furthermore, our study reveals a fragment-like core that maintains low μM affinity and robust negative cooperativity with markedly improved ligand efficiency.- Published
- 2019
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30. An Alternative Platform for Protein Expression Using an Innate Whole Expression Module from Metagenomic DNA.
- Author
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Cheong DE, Park SY, Lim HD, and Kim GJ
- Abstract
Many integrated gene clusters beyond a single genetic element are commonly trapped as the result of promoter traps in (meta)genomic DNA libraries. Generally, a single element, which is mainly the promoter, is deduced from the resulting gene clusters and employed to construct a new expression vector. However, expression patterns of target proteins under the incorporated promoter are often inconsistent with those shown in clones harboring plasmids with gene clusters. These results suggest that the integrated set of gene clusters with diverse cis- and trans-acting elements is evolutionarily tuned as a complete set for gene expression, and is an expression module with all the components for the expression of a nested open reading frame (ORF). This possibility is further supported by truncation and/or serial deletion analysis of this module in which the expression of the nested ORF is highly fluctuated or reduced frequently, despite being supported by plentiful cis-acting elements in the spanning regions around the ORF such as the promoter, ribosome binding site (RBS), terminator, and 3'-/5'-UTRs for gene expression. Here, we examined whether an innate module with a naturally overexpressed gene could be considered as a scaffold for an expression system. For a proof-of-principle study, we mined a complete expression module with an innately overexpressed ORF in E. coli from a metagenomics DNA library, and incorporated it into a vector that had no regulatory element for expressing the insert. We obtained successful expression of several inserts such as MBP, GFPuv, β-glucosidase, and esterase using this simple construct without tuning and codon optimization of the target insert.
- Published
- 2019
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31. Dendrite Suppression Membranes for Rechargeable Zinc Batteries.
- Author
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Lee BS, Cui S, Xing X, Liu H, Yue X, Petrova V, Lim HD, Chen R, and Liu P
- Abstract
Aqueous batteries with zinc metal anodes are promising alternatives to Li-ion batteries for grid storage because of their abundance and benefits in cost, safety, and nontoxicity. However, short cyclability due to zinc dendrite growth remains a major obstacle. Here, we report a cross-linked polyacrylonitrile (PAN)-based cation exchange membrane that is low cost and mechanically robust. Li
2 S3 reacts with PAN, simultaneously leading to cross-linking and formation of sulfur-containing functional groups. Hydrolysis of the membrane results in the formation of a membrane that achieves preferred cation transport and homogeneous ionic flux distribution. The separator is thin (30 μm-thick), almost 9 times stronger than hydrated Nafion, and made of low-cost materials. The membrane separator enables exceptionally long cyclability (>350 cycles) of Zn/Zn symmetric cells with low polarization and effective dendrite suppression. Our work demonstrates that the design of new separators is a fruitful pathway to enhancing the cyclability of aqueous batteries.- Published
- 2018
- Full Text
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32. Recent Progress in Organic Electrodes for Li and Na Rechargeable Batteries.
- Author
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Lee S, Kwon G, Ku K, Yoon K, Jung SK, Lim HD, and Kang K
- Abstract
Organic rechargeable batteries, which use organics as electrodes, are excellent candidates for next-generation energy storage systems because they offer design flexibility due to the rich chemistry of organics while being eco-friendly and potentially cost efficient. However, their widespread usage is limited by intrinsic problems such as poor electronic conductivity, easy dissolution into liquid electrolytes, and low volumetric energy density. New types of organic electrode materials with various redox centers or molecular structures have been developed over the past few decades. Moreover, research aimed at enhancing electrochemical properties via chemical tuning has been at the forefront of organic rechargeable batteries research in recent years, leading to significant progress in their performance. Here, an overview of the current developments of organic rechargeable batteries is presented, with a brief history of research in this field. Various strategies for improving organic electrode materials are discussed with respect to tuning intrinsic properties of organics using molecular modification and optimizing their properties at the electrode level. A comprehensive understanding of the progress in organic electrode materials is provided along with the fundamental science governing their performance in rechargeable batteries thus a guide is presented to the optimal design strategies to improve the electrochemical performance for next-generation battery systems., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2018
- Full Text
- View/download PDF
33. Smartphone use and schema-based learning in dentomaxillofacial radiology practice: a case report from one College of Dentistry.
- Author
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Ji YA, Lee YM, Lim HD, Park WJ, Jung JH, Lee JW, and Lee BD
- Subjects
- Dentistry, Humans, Students, Dental, Education, Dental, Radiology, Smartphone
- Abstract
Objectives: This study investigates the students' satisfaction and awareness of competency towards smartphone use and schema-based learning in dental radiology practice., Methods: Third year students undertaking a dental radiology practicum at a dental school were divided into two groups: one group received traditional clinical training, whereas the other group used smartphones in classes and received new training using schema assignments. At the end of the course, students' satisfaction with the training and self-awareness of their competency were surveyed, and their achievement was assessed., Results: Although students' satisfaction with smartphone-based training was generally high, it was less than that of students trained by traditional instruction. However, most students that received smartphone-based training had higher self-scored competency before than after training. The smartphone group scored higher on true/false or multiple-choice questions, whereas the traditional group scored higher on short-answer questions., Conclusions: Smartphone education with schema based assignment proved to be attractive in dental radiology, but students showed less satisfaction, and need to meet the requirements of evidence-based practice. Although the full use of smartphone education with schema is not recommended in dental education, we think that it could be try to use as a supplementary approach with traditional didactic method to facilitate student's exploration and self-study to cope with rapid change in educational environment.
- Published
- 2018
- Full Text
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34. Conditional constitutive expression system of a drug protein in vivo by positive feedback loop using an inducer-independent artificial transcription factor.
- Author
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Lee EB, Lim HD, You SH, Cheong DE, and Kim GJ
- Subjects
- Feedback, Transcription Factors, Bacterial Proteins genetics, Delayed-Action Preparations administration & dosage, Escherichia coli genetics, Genetic Engineering methods, Promoter Regions, Genetic genetics, Recombinant Proteins administration & dosage, Recombinant Proteins genetics
- Abstract
Bacterial-mediated drug delivery is a potential and promising strategy for the specific treatment of cancer with therapeutic molecules, especially with genetically encoded proteins. These proteins must be tightly regulated due to cytotoxicity and thus are usually expressed under the control of the P
BAD and TetA/TetR promoters in vivo. Since protein expression from these systems is triggered by exogenous inducer, periodic intravenous injection of inducer is necessary. However, these treatments can result in non-homogenous and/or inefficient expression of therapeutic proteins in vivo due to impeded diffusion and dilution of the inducer further from the injection site. To overcome these hurdles, we designed a conditional constitutive expression system equipped with the artificial transcription factor, AraCC , which has two operator-binding domains and simultaneously binds to the I1 and I2 operators of the PBAD promoter for gene expression in an arabinose-independent manner. Using this construct and the wild type protein AraC under the control of the PBAD promoter, we constructed a self-positive feedback system to constitutively express the therapeutic protein when the induction of AraC was triggered once using arabinose. This expression system could be useful in various cancer treatment strategies using bacteria to deliver genetically encoded drugs in vivo., (Copyright © 2017 Elsevier Inc. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
35. Cell mass-dependent expression of an anticancer protein drug by tumor-targeted Salmonella .
- Author
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Kim K, Min SY, Lim HD, You SH, Lim D, Jeong JH, Kim HJ, Rhee JH, Park K, Shin M, Kim GJ, Min JJ, and Choy HE
- Abstract
Bacterial cancer therapy relies on the properties of certain bacterial species capable of targeting and proliferating within solid malignancies. If these bacteria could be loaded with antitumor proteins, the efficacy of this approach could be greatly increased. However, because most antitumor proteins are also toxic to normal tissue, they must be expressed by bacteria that specifically target and exclusively localize to tumor tissue. As a strategy for treating solid malignancies, we recently evaluated L-asparaginase (L-ASNase) delivered by tumor-targeted Salmonella . In this system, L-ASNase was expressed under the control of the araBAD promoter ( PBAD ) of the E. coli arabinose operon, which is induced by injection of L-arabinose. Here, we further improved the performance of recombinant Salmonella in cancer therapy by exploiting the quorum-sensing (QS) system, which uses cell mass-dependent auto-induction logic. This approach obviates the necessity of monitoring intratumoral bacterial status and inducing cargo protein expression by administration of an exogenous compound. Recombinant Salmonella in tumors expressed and secreted active L-ASNase in a cell mass-dependent manner, yielding significant anticancer effects. These results suggest that expression of a therapeutic protein under the control of the QS system represents a promising engineering platform for the production of recombinant proteins in vivo ., Competing Interests: CONFLICTS OF INTEREST The authors do not have any conflicts of interest.
- Published
- 2018
- Full Text
- View/download PDF
36. Superoxide stability for reversible Na-O 2 electrochemistry.
- Author
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Dilimon VS, Hwang C, Cho YG, Yang J, Lim HD, Kang K, Kang SJ, and Song HK
- Abstract
Stabilizing superoxide (O
2 - ) is one of the key issues of sodium-air batteries because the superoxide-based discharge product (NaO2 ) is more reversibly oxidized to oxygen when compared with peroxide (O2 2- ) and oxide (O2- ). Reversibly outstanding performances of sodium-oxygen batteries have been realized with the superoxide discharge product (NaO2 ) even if sodium peroxide (Na2 O2 ) have been also known as the discharge products. Here we report that the Lewis basicity of anions of sodium salts as well as solvent molecules, both quantitatively represented by donor numbers (DNs), determines the superoxide stability and resultantly the reversibility of sodium-oxygen batteries. A DN map of superoxide stability was presented as a selection guide of salt/solvent pair. Based on sodium triflate (CF3 SO3 - )/dimethyl sulfoxide (DMSO) as a high-DN-pair electrolyte system, sodium ion oxygen batteries were constructed. Pre-sodiated antimony (Sb) was used as an anode during discharge instead of sodium metal because DMSO is reacted with the metal. The superoxide stability supported by the high DN anion/solvent pair ([Formula: see text]- /DMSO) allowed more reversible operation of the sodium ion oxygen batteries.- Published
- 2017
- Full Text
- View/download PDF
37. Induction of α6 and β1 integrins by acupuncture stimulation in rats.
- Author
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Shin HC, Park JY, Lim HD, and Namgung U
- Subjects
- Acupuncture Points, Animals, Male, Mechanotransduction, Cellular immunology, Neuralgia diagnosis, Physical Stimulation methods, Rats, Rats, Sprague-Dawley, Treatment Outcome, Acupuncture Therapy methods, Integrin alpha6 immunology, Integrin beta1 immunology, MAP Kinase Signaling System immunology, Neuralgia immunology, Neuralgia therapy
- Abstract
Acupuncture therapy is performed by applying the needle insertion at discrete cutaneous locations and used for the treatments of diverse symptoms and disorders. In order to elucidate mechanistic basis on how acupuncture stimulation (AS) produces therapeutic effects, it is primarily important to understand tissue responses locally at the acupuncture site (acupoint). Here, we investigated integrin protein as molecular target responding to and integrating AS. Signals of α6 and β1 integrins were clearly induced at zusanli acupoint 24 h after AS in areas of nuclear clusters around the needle track. Induction levels of integrin were largely reduced by needle insertion at non-acupuncture point or without needle rotation. Phospho-Erk1/2 was initially decreased below the basal level after AS but increased 24 h later. Induction pattern of phospho-Erk1/2 was as similar as that of α6 integrin in its selectivity to needling procedure and tissue distribution. We further found that mRNA expression of P2X3 purinergic receptor was upregulated in the dorsal root ganglion (DRG) after AS, but decreased by the inhibition of Erk1/2 activity at the acupuncture area. Moreover, AS-mediated integrin activation was required for Erk1/2 activation at the acupuncture site and regulation of pain sensitivity in the hind paw. The present results provide a new evidence on acupuncture-specific tissue response in terms of integrin induction, and further suggest that integrin activation may be involved in transmitting mechanosensory signals from the acupoint to afferent nerve fiber., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
38. Antimicrobial and Anti-Biofilm Activities of the Methanol Extracts of Medicinal Plants against Dental Pathogens Streptococcus mutans and Candida albicans .
- Author
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Choi HA, Cheong DE, Lim HD, Kim WH, Ham MH, Oh MH, Wu Y, Shin HJ, and Kim GJ
- Subjects
- Biofilms drug effects, Candida albicans physiology, Dental Caries drug therapy, Methanol, Microbial Sensitivity Tests, Mouth microbiology, Plant Extracts chemistry, Plant Extracts isolation & purification, Plants, Medicinal chemistry, Republic of Korea, Streptococcus mutans physiology, Anti-Bacterial Agents pharmacology, Candida albicans drug effects, Plant Extracts pharmacology, Streptococcus mutans drug effects
- Abstract
Several medicinal plants are ethnomedically used in Korea as agents for treating infection, anti-inflammation, and pain relief. However, beyond typical inhibitory effects on cell growth, little is known about the potential anti-biofilm activity of these herbs, which may help to prevent cavities and maintain good oral health. This study aimed to investigate the antimicrobial and anti-biofilm activities of the methanol extracts of 37 Korean medicinal plants against dental pathogens Streptococcus mutans and Candida albicans , which synergize their virulence so as to induce the formation of plaque biofilms in the oral cavity. The antimicrobial activities were investigated by broth dilution and disk diffusion assay. The anti-biofilm and antioxidant activities were evaluated based on the inhibitory effect against glucosyltransferase (GTase) and the DPPH assay, respectively. Among 37 herbs, eight plant extracts presented growth and biofilm inhibitory activities against both etiologic bacteria. Among them, the methanol extracts (1.0 mg/ml) from Camellia japonica and Thuja orientalis significantly inhibited the growth of both bacteria by over 76% and over 83% in liquid media, respectively. Minimum inhibitory concentration (MIC) values of these methanol extracts were determined to be 0.5 mg/ml using a disk diffusion assay on solid agar media. Biofilm formation was inhibited by more than 92.4% and 98.0%, respectively, using the same concentration of each extract. The present results demonstrate that the medicinal plants C. japonica and T. orientalis are potentially useful as antimicrobial and anti-biofilm agents in preventing dental diseases.
- Published
- 2017
- Full Text
- View/download PDF
39. Key determinants of selective binding and activation by the monocyte chemoattractant proteins at the chemokine receptor CCR2.
- Author
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Huma ZE, Sanchez J, Lim HD, Bridgford JL, Huang C, Parker BJ, Pazhamalil JG, Porebski BT, Pfleger KDG, Lane JR, Canals M, and Stone MJ
- Subjects
- Amino Acid Sequence, Chemokine CCL2 chemistry, Chemokine CCL2 metabolism, Chemokine CCL7 chemistry, Chemokine CCL7 metabolism, Humans, Models, Molecular, Protein Binding, Receptors, CCR2 genetics, Sequence Homology, Chemokines chemistry, Chemokines metabolism, Receptors, CCR2 chemistry, Receptors, CCR2 metabolism
- Abstract
Chemokines and their receptors collectively orchestrate the trafficking of leukocytes in normal immune function and inflammatory diseases. Different chemokines can induce distinct responses at the same receptor. In comparison to monocyte chemoattractant protein-1 (MCP-1; also known as CCL2), the chemokines MCP-2 (CCL8) and MCP-3 (CCL7) are partial agonists of their shared receptor CCR2, a key regulator of the trafficking of monocytes and macrophages that contribute to the pathology of atherosclerosis, obesity, and type 2 diabetes. Through experiments with chimeras of MCP-1 and MCP-3, we identified the chemokine amino-terminal region as being the primary determinant of both the binding and signaling selectivity of these two chemokines at CCR2. Analysis of CCR2 mutants showed that the chemokine amino terminus interacts with the major subpocket in the transmembrane helical bundle of CCR2, which is distinct from the interactions of some other chemokines with the minor subpockets of their receptors. These results suggest the major subpocket as a target for the development of small-molecule inhibitors of CCR2., (Copyright © 2017, American Association for the Advancement of Science.)
- Published
- 2017
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40. Reaction chemistry in rechargeable Li-O 2 batteries.
- Author
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Lim HD, Lee B, Bae Y, Park H, Ko Y, Kim H, Kim J, and Kang K
- Abstract
The seemingly simple reaction of Li-O
2 batteries involving lithium and oxygen makes this chemistry attractive for high-energy-density storage systems; however, achieving this reaction in practical rechargeable Li-O2 batteries has proven difficult. The reaction paths leading to the final Li2 O2 discharge products can be greatly affected by the operating conditions or environment, which often results in major side reactions. Recent research findings have begun to reveal how the reaction paths may be affected by the surrounding conditions and to uncover the factors contributing to the difficulty in achieving the reactions of lithium and oxygen. This progress report describes the current state of understanding of the electrode reaction mechanisms in Li-O2 batteries; the factors that affect reaction pathways; and the effect of cell components such as solvents, salts, additives, and catalysts on the discharge product and its decomposition during charging. This comprehensive review of the recent progress in understanding the reaction chemistry of the Li-O2 system will serve as guidelines for future research and aid in the development of reliable high-energy-density rechargeable Li-O2 batteries.- Published
- 2017
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41. High-efficiency and high-power rechargeable lithium-sulfur dioxide batteries exploiting conventional carbonate-based electrolytes.
- Author
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Park H, Lim HD, Lim HK, Seong WM, Moon S, Ko Y, Lee B, Bae Y, Kim H, and Kang K
- Abstract
Shedding new light on conventional batteries sometimes inspires a chemistry adoptable for rechargeable batteries. Recently, the primary lithium-sulfur dioxide battery, which offers a high energy density and long shelf-life, is successfully renewed as a promising rechargeable system exhibiting small polarization and good reversibility. Here, we demonstrate for the first time that reversible operation of the lithium-sulfur dioxide battery is also possible by exploiting conventional carbonate-based electrolytes. Theoretical and experimental studies reveal that the sulfur dioxide electrochemistry is highly stable in carbonate-based electrolytes, enabling the reversible formation of lithium dithionite. The use of the carbonate-based electrolyte leads to a remarkable enhancement of power and reversibility; furthermore, the optimized lithium-sulfur dioxide battery with catalysts achieves outstanding cycle stability for over 450 cycles with 0.2 V polarization. This study highlights the potential promise of lithium-sulfur dioxide chemistry along with the viability of conventional carbonate-based electrolytes in metal-gas rechargeable systems.
- Published
- 2017
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42. Enhanced axonal regeneration of the injured sciatic nerve by administration of Buyang Huanwu decoction.
- Author
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Chang IA, Lim HD, Kim KJ, Shin H, and Namgung U
- Subjects
- Animals, Behavior, Animal, Rats, Rats, Sprague-Dawley, Sciatic Nerve physiopathology, Axons, Drugs, Chinese Herbal pharmacology, Nerve Regeneration drug effects, Sciatic Nerve injuries
- Abstract
Ethnopharmacological Relevance: Buyang Huanwu decoction (BYHWD) has been used in the traditional Chinese medicine for the treatment of cardiovascular and neurological symptoms, and recent experimental studies have begun to provide evidence showing its protective effects on neural cells. Yet, its function for the regenerative responses of axons in the peripheral nerve after injury is not known., Aim of the Study: The primary objective of the present study was to explore that BYHWD is involved in growth-promoting activity of the peripheral nerve axons after injury. We further examined whether the effect of BYHWD exerted directly on regrowing axons or Schwann cells., Materials and Methods: Sciatic nerves in rats were given crush injury, and BYHWD was injected by oral administration. Sciatic nerves or DRG tissues were prepared for immunofluorescence staining and western blot analysis. Levels of axonal regeneration were quantified by retrograde tracing technique. Cultured DRG sensory neurons and Schwann cells were prepared from rats and used to examine the effects of BYHWD on the neurite outgrowth. Behavioral analysis on functional recovery after nerve injury was assessed in mice by pin prick test, adhesive removal test, and toe-spreading reflex., Results: Immunofluorescence and retrograde tracing analyses showed that the distal extension of the sciatic nerve axons was significantly improved by BYHWD treatment. Levels of axonal growth-associated protein GAP-43 were upregulated by BYHWD treatment in the sciatic nerve after injury and in the neurites of cultured DRG neurons. In vivo administration of BYHWD in rats upregulated the induction level of cell division cycle 2 (Cdc2) and its phosphorylation of vimentin in Schwann cells from injured sciatic nerve. Coculture of DRG neurons with Schwann cells prepared from preinjured sciatic nerves in animals administered with BYHWD led to the enhancement in neurite outgrowth. Behavioral tests in mice given sciatic nerve injury showed a significant improvement in sensorimotor activity by BYHWD administration., Conclusions: Our results suggest that BYHWD administration into animals given sciatic nerve injury facilitates axonal regeneration by acting on both the axons undergoing regeneration and neighboring Schwann cells and improves functional recovery., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2016
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43. BST2 Mediates Osteoblast Differentiation via the BMP2 Signaling Pathway in Human Alveolar-Derived Bone Marrow Stromal Cells.
- Author
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Yoo SH, Kim JG, Kim BS, Lee J, Pi SH, Lim HD, Shin HI, Cho ES, and You HK
- Subjects
- Bone Marrow Cells drug effects, Cell Differentiation drug effects, Cells, Cultured, GPI-Linked Proteins antagonists & inhibitors, GPI-Linked Proteins physiology, Gene Expression Regulation drug effects, Humans, Mesenchymal Stem Cells drug effects, Middle Aged, Osteoblasts drug effects, Osteogenesis drug effects, Osteogenesis genetics, RNA, Small Interfering pharmacology, Signal Transduction drug effects, Signal Transduction genetics, Antigens, CD physiology, Bone Marrow Cells physiology, Bone Morphogenetic Protein 2 physiology, Cell Differentiation genetics, Mesenchymal Stem Cells physiology, Osteoblasts physiology
- Abstract
The molecular mechanisms controlling the differentiation of bone marrow stromal stem cells into osteoblasts remain largely unknown. In this study, we investigated whether bone marrow stromal antigen 2 (BST2) influences differentiation toward the osteoblasts lineage. BST2 mRNA expression in human alveolar-derived bone marrow stromal cells (hAD-BMSCs) increased during differentiation into osteoblasts. hAD-BMSCs differentiation into osteoblasts and the mRNA expression of the bone-specific markers alkaline phosphatase, collagen type α 1, bone sialoprotein, osteocalcin, and osterix were reduced by BST2 knockdown using siRNA. Furthermore, BST2 knockdown in hAD-BMSCs resulted in decreased RUNX2 mRNA and protein expression. We hypothesized that BST2 is involved in differentiation of into osteoblasts via the BMP2 signaling pathway. Accordingly, we evaluated the mRNA expression levels of BMP2, BMP receptors (BMPR1 and 2), and the downstream signaling molecules SMAD1, SMAD4, and p-SMAD1/5/8 in BST2 knockdown cells. BMP2 expression following the induction of differentiation was significantly lower in BST2 knockdown cells than in cells treated with a non-targeting control siRNA. Similar results were found for the knockdown of the BMP2 receptor- BMPR1A. We also identified significantly lower expression of SMAD1, SMAD4, and p-SMAD1/5/8 in the BST2 knockdown cells than control cells. Our data provide the first evidence that BST2 is involved in the osteogenic differentiation of bone marrow stromal cells via the regulation of the BMP2 signaling pathway.
- Published
- 2016
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44. Anti-Inflammatory Effects of Acupuncture Stimulation via the Vagus Nerve.
- Author
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Lim HD, Kim MH, Lee CY, and Namgung U
- Subjects
- Acupuncture Points, Animals, Electroacupuncture, Male, Mice, Inbred BALB C, Proto-Oncogene Proteins c-fos metabolism, Solitary Nucleus metabolism, Tumor Necrosis Factor-alpha metabolism, Vagotomy, Acupuncture Therapy, Inflammation therapy, Vagus Nerve physiology
- Abstract
Although acupuncture therapy is widely used in traditional Asian medicine for the treatment of diverse internal organ disorders, its underlying biological mechanisms are largely unknown. Here, we investigated the functional involvement of acupuncture stimulation (AS) in the regulation of inflammatory responses. TNF-α production in mouse serum, which was induced by lipopolysaccharide (LPS) administration, was decreased by manual acupuncture (MAC) at the zusanli acupoint (stomach36, ST36). In the spleen, TNF-α mRNA and protein levels were also downregulated by MAC and were recovered by using a splenic neurectomy and a vagotomy. c-Fos, which was induced in the nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus nerve (DMV) by LPS and electroacupuncture (EAC), was further increased by focal administration of the AMPA receptor blocker CNQX and the purinergic receptor antagonist PPADS. TNF-α levels in the spleen were decreased by CNQX and PPADS treatments, implying the involvement of inhibitory neuronal activity in the DVC. In unanesthetized animals, both MAC and EAC generated c-Fos induction in the DVC neurons. However, MAC, but not EAC, was effective in decreasing splenic TNF-α production. These results suggest that the therapeutic effects of acupuncture may be mediated through vagal modulation of inflammatory responses in internal organs.
- Published
- 2016
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45. Dissolution and ionization of sodium superoxide in sodium-oxygen batteries.
- Author
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Kim J, Park H, Lee B, Seong WM, Lim HD, Bae Y, Kim H, Kim WK, Ryu KH, and Kang K
- Abstract
With the demand for high-energy-storage devices, the rechargeable metal-oxygen battery has attracted attention recently. Sodium-oxygen batteries have been regarded as the most promising candidates because of their lower-charge overpotential compared with that of lithium-oxygen system. However, conflicting observations with different discharge products have inhibited the understanding of precise reactions in the battery. Here we demonstrate that the competition between the electrochemical and chemical reactions in sodium-oxygen batteries leads to the dissolution and ionization of sodium superoxide, liberating superoxide anion and triggering the formation of sodium peroxide dihydrate (Na2O2·2H2O). On the formation of Na2O2·2H2O, the charge overpotential of sodium-oxygen cells significantly increases. This verification addresses the origin of conflicting discharge products and overpotentials observed in sodium-oxygen systems. Our proposed model provides guidelines to help direct the reactions in sodium-oxygen batteries to achieve high efficiency and rechargeability.
- Published
- 2016
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46. A New Perspective on Li-SO2 Batteries for Rechargeable Systems.
- Author
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Lim HD, Park H, Kim H, Kim J, Lee B, Bae Y, Gwon H, and Kang K
- Abstract
Primary Li-SO2 batteries offer a high energy density in a wide operating temperature range with exceptionally long shelf life and have thus been frequently used in military and aerospace applications. Although these batteries have never been demonstrated as a rechargeable system, herein, we show that the reversible formation of Li2S2O4, the major discharge product of Li-SO2 battery, is possible with a remarkably smaller charging polarization than that of a Li-O2 battery without the use of catalysts. The rechargeable Li-SO2 battery can deliver approximately 5400 mAh g(-1) at 3.1 V, which is slightly higher than the performance of a Li-O2 battery. In addition, the Li-SO2 battery can be operated with the aid of a redox mediator, exhibiting an overall polarization of less than 0.3 V, which results in one of the highest energy efficiencies achieved for Li-gas battery systems., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2015
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47. Proof of concept study for designed multiple ligands targeting the dopamine D2, serotonin 5-HT2A, and muscarinic M1 acetylcholine receptors.
- Author
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Szabo M, Lim HD, Herenbrink CK, Christopoulos A, Lane JR, and Capuano B
- Subjects
- Benzoxazines chemical synthesis, Benzoxazines chemistry, Dopamine D2 Receptor Antagonists chemical synthesis, Dopamine D2 Receptor Antagonists chemistry, Dose-Response Relationship, Drug, Ligands, Molecular Structure, Receptor, Muscarinic M1 metabolism, Serotonin 5-HT2 Receptor Antagonists chemical synthesis, Serotonin 5-HT2 Receptor Antagonists chemistry, Structure-Activity Relationship, Benzoxazines pharmacology, Dopamine D2 Receptor Antagonists pharmacology, Drug Design, Receptor, Muscarinic M1 antagonists & inhibitors, Receptor, Serotonin, 5-HT2A metabolism, Receptors, Dopamine D2 metabolism, Serotonin 5-HT2 Receptor Antagonists pharmacology
- Abstract
Herein we describe the hybridization of a benzoxazinone M1 scaffold with D2 privileged structures derived from putative and clinically relevant antipsychotics to develop designed multiple ligands. The M1 mAChR is an attractive target for the cognitive deficits in key CNS disorders. Moreover, activity at D2 and 5-HT2A receptors has proven useful for antipsychotic efficacy. We identified 9 which retained functional activity at the target M1 mAChR and D2R and demonstrated high affinity for the 5-HT2AR.
- Published
- 2015
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48. Synthesis and characterization of monodispersed β-Ga₂O₃ nanospheres via morphology controlled Ga₄(OH)₁₀SO₄ precursors.
- Author
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Kang BK, Lim HD, Mang SR, Song KM, Jung MK, Kim SW, and Yoon DH
- Abstract
To our best knowledge, monodispersed β-Ga2O3 nanospheres were successfully synthesized for first time via morphology-controlled gallium precursors using the forced hydrolysis method, followed by thermal calcination processes. The morphology and particle sizes of the gallium precursors were strongly dependent on the varying (R = SO4(2-)/NO3(-)) concentration ratios. As R decreased, the size of the prepared gallium precursors decreased and morphology was altered from sphere to rod. The synthesized S2 (R = 0.33) consists of uniform and monodispersed amorphous nanospheres with diameters of about 200 nm. The monodispersed β-Ga2O3 nanospheres were synthesized using thermal calcination processes at various temperatures ranging from 500 to 1000 °C. Monodispersed β-Ga2O3 nanospheres (200 nm) consist of small particles of approximately 10-20 nm with rough surface at 1000 °C for 1 h. The UV (375 nm) and broad blue (400-450 nm) emission indicate recombination via a self-trapped exciton and the defect band emission. Our approach described here is to show the exploration of β-Ga2O3 nanospheres as an automatic dispersion, three-dimensional support for fabrication of hierarchical materials, which is potentially important for a broad range of optoelectronic applications.
- Published
- 2015
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49. Organic nanohybrids for fast and sustainable energy storage.
- Author
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Lee M, Hong J, Kim H, Lim HD, Cho SB, Kang K, and Park CB
- Abstract
A nanohybridization strategy is presented for the fabrication of high performance lithium ion batteries based on redox-active organic molecules. The rearrangement of electroactive aromatic molecules from bulk crystalline particles into molecular layers is achieved by non-covalent nanohybridization of active molecules with conductive scaffolds. As a result, nano-hybrid organic electrodes in the form of a flexible self-standing paper-free of binder/additive and current collector-are synthesized, which exhibit high energy and power densities combined with excellent cyclic stability., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2014
- Full Text
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50. Superior rechargeability and efficiency of lithium-oxygen batteries: hierarchical air electrode architecture combined with a soluble catalyst.
- Author
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Lim HD, Song H, Kim J, Gwon H, Bae Y, Park KY, Hong J, Kim H, Kim T, Kim YH, Lepró X, Ovalle-Robles R, Baughman RH, and Kang K
- Abstract
The lithium-oxygen battery has the potential to deliver extremely high energy densities; however, the practical use of Li-O2 batteries has been restricted because of their poor cyclability and low energy efficiency. In this work, we report a novel Li-O2 battery with high reversibility and good energy efficiency using a soluble catalyst combined with a hierarchical nanoporous air electrode. Through the porous three-dimensional network of the air electrode, not only lithium ions and oxygen but also soluble catalysts can be rapidly transported, enabling ultra-efficient electrode reactions and significantly enhanced catalytic activity. The novel Li-O2 battery, combining an ideal air electrode and a soluble catalyst, can deliver a high reversible capacity (1000 mAh g(-1) ) up to 900 cycles with reduced polarization (about 0.25 V)., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2014
- Full Text
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