Publications by authors named "Hyosung Lee"

Article Synopsis
  • - The management of unknown weapons from warfare and terrorism involves nondestructive testing to identify and process these weapons, focusing on their safe transportation and storage.
  • - Traditional methods use radiation-based analyses for identification, which require specialized experts and facilities, making them difficult to implement.
  • - An innovative nondestructive ultrasonic testing method has been developed to analyze the internal composition of unknown weapons, particularly effective for detecting liquids, paving the way for a more accessible approach to weapon management.
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Various electrocatalysts are extensively examined for their ability to selectively produce desired products by electrochemical CO reduction reaction (CORR). However, an efficient CORR electrocatalyst doesn't ensure an effective co-catalyst on the semiconductor surface for photoelectrochemical CORR. Herein, BiS nanorods are synthesized and electrochemically reduced to Bi nanoplates that adhere to the substrates for application in the electrochemical and photoelectrochemical CORR.

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Non-destructive stress measurement by ultrasonic testing is based on calculating the acoustoelastic modulus obtained from the relationship between material stress and sound wave velocity. A critically refracted longitudinal (L) wave, which is a bulk longitudinal wave penetrating below and parallel to the surface below an effective depth, is most suitable for ultrasonic stress measurement tests because it exhibits a relatively large change in travel time in response to a change in stress. In particular, the residual stress distribution through the thickness of the subject can be calculated if transducers of different frequencies are applied because of the characteristic of propagation to different depths of penetration depending on the frequency.

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Bee venom is a medicinal product that is widely used in traditional therapies owing to its excellent anti-inflammatory activity. However, the use of bee venom has shown adverse effects. Therefore, there is a need for research that can remove the cytotoxicity of bee venom and enhance its efficacy.

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A 26-GHz transmitter front-end is designed using 65 nm CMOS technology. The double frequency conversion transmitter consists of an intermediate frequency(IF) mixer, an millimeter-wave(mm-wave) mixer, and a pre-power amplifier. A double quadrature architecture is employed to accomplish image rejection without using an image rejection filter for the first time in the mm-wave frequency band.

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The quest for developing anticancer principles from natural sources has a long historical track record and remarkable success stories. The pungent principle of hot chili pepper, capsaicin, has been a subject of research for anticancer drug discovery for more than three decades. However, the majority of research has revealed that capsaicin interferes with various hallmarks of cancer, such as increased cell proliferation, evasion from apoptosis, inflammation, tumor angiogenesis and metastasis, and tumor immune escape.

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3-Deoxysappanchalcone (3-DSC) has been reported to possess anti-allergic, antiviral, anti-inflammatory and antioxidant activities. In the present study, we investigated the effects of 3-DSC on the proliferation of human hair follicle dermal papilla cells (HDPCs) and mouse hair growth . A real-time cell analyzer system, luciferase assay, Western blot and real-time polymerase chain reaction (PCR) were employed to measure the biochemical changes occurring in HDPCs in response to 3-DSC treatment.

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Proton-substitution effects of 4-hydroxy-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-6-one (HPPCO) on structural and photophysical properties were presented. HPPCO crystallized in the orthorhombic space group Pbca with an intermolecular hydrogen bonding between OH and oxygen atom of the carbonyl. The proton-substituted derivatives, 6-oxo-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-4-yl acetate (OPPCA) and 6-oxo-5-phenyl-6H-pyrido[3,2,1-jk]carbazol-4-yl benzoate (OPPCB), crystallized in the monoclinic P2₁/c space group.

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We prepared 13 derivatives of N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamide that differed in type and placement of a R-substituent in the terminal aryl unit. We demonstrated that the R-substituent impacted the compound's whole animal and cellular pharmacological activities. In rodents, select compounds exhibited excellent anticonvulsant activities and protective indices (PI=TD50/ED50) that compared favorably with clinical antiseizure drugs.

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The fabrication of well-ordered metal nanoparticle structures onto a desired substrate can be effectively applied to several applications. In this work, well-ordered Ag nanoparticle line arrays were printed on the desired substrate without the use of glue materials. The success of the method relies on the assembly of Ag nanoparticles on the anisotropic buckling templates and a special transfer process where a small amount of water rather than glue materials is employed.

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Several antiepileptic drugs exert their activities by inhibiting Na(+) currents. Recent studies demonstrated that compounds containing a biaryl-linked motif (Ar-X-Ar') modulate Na(+) currents. We, and others, have reported that compounds with an embedded benzyloxyphenyl unit (ArOCH2Ar', OCH2=X) exhibit potent anticonvulsant activities.

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Background: Large lumbar disc herniation (LDH) has been reported to have a greater tendency to resolve in clinical and pathomorphological evolutions. However, various definitions of large LDH have been used without validation, and the clinical symptoms of large LDH have not been fully elucidated. We conducted a retrospective analysis to determine the clinical characteristics and treatment outcome of massive LDH with complete dural sac stenosis.

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We have reported that compounds containing a biaryl linked unit (Ar-X-Ar') modulated Na(+) currents by promoting slow inactivation and fast inactivation processes and by inducing frequency (use)-dependent inhibition of Na(+) currents. These electrophysiological properties have been associated with the mode of action of several antiepileptic drugs. In this study, we demonstrate that the readily accessible (biphenyl-4-yl)methylammonium chlorides (compound class B) exhibited a broad range of anticonvulsant activities in animal models, and in the maximal electroshock seizure test the activity of (3'-trifluoromethoxybiphenyl-4-yl)methylammonium chloride (8) exceeded that of phenobarbital and phenytoin upon oral administration to rats.

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Lacosamide ((R)-1) is a recently marketed, first-in-class, antiepileptic drug. Patch-clamp electrophysiology studies are consistent with the notion that (R)-1 modulates voltage-gated Na(+) channel function by increasing and stabilizing the slow inactivation state without affecting fast inactivation. The molecular pathway(s) that regulate slow inactivation are poorly understood.

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Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that regulates genes involved in drug/xenobiotic metabolism, cell cycle progression, cell fate determination, immune function, and inflammatory response. Increasing evidence that AHR plays a role in the pathophysiology of a number of human disease states is driving the need for improved pharmacological tools to be used for understanding the in vivo impact of AHR modulation. In this study, we have characterized and used structure-activity relationship analyses of a newly synthesized library of derivatives of the potent AHR antagonist 2-methyl-2H-pyrazole-3-carboxylic acid (2-methyl-4-o-tolylazo-phenyl)-amide (CH223191).

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A detailed photophysical analysis of 4-hydroxy-5-phenylpyrido[3,2,1-jk]carbazol-6-one (HPPCO) is presented. When exposed to UV light, the compound produced deep blue to green luminescence, depending on the solvent. The luminescence peak shifts with the Gutmann donor number (DN) of the solvent and the proton substitution affects luminescence; a correlation between quantum yield and decay time indicated that proton transfer plays a key role in the observed solvatochromism.

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Conventional genetic approaches have provided a powerful tool in the study of proteins. However, these techniques often preclude selective manipulation of temporal and spatial protein functions, which is crucial for the investigation of dynamic cellular processes. To overcome these limitations, a small molecule-based novel technology termed "PROteolysis TArgeting ChimeraS (PROTACs)" has been developed, targeting proteins for degradation at the post-translational level.

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Estrogen receptor-alpha (ER) antagonists have been widely used for breast cancer therapy. Despite initial responsiveness, hormone-sensitive ER-positive cancer cells eventually develop resistance to ER antagonists. It has been shown that in most of these resistant tumor cells, the ER is expressed and continues to regulate tumor growth.

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Kaurane diterpene compounds have been known to be cytotoxic against several cancer cells through inhibition of nuclear factor-kappaB (NF-kappaB) activity. Here, we showed that inflexinol, a novel kaurane diterpene compound, inhibited the activity of NF-kappaB and its target gene expression as well as cancer cell growth through induction of apoptotic cell death in vitro and in vivo. These inhibitory effects on NF-kappaB activity and on cancer cell growth were suppressed by the reducing agents DTT and glutathione and were abrogated in the cells transfected with mutant p50 (C62S).

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Activation of the aryl hydrocarbon receptor (AHR) by agonists and environmental contaminants like dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) leads to many adverse biological effects, including tumor promotion. With this in mind, we propose that agents that block the AHR pathway may be therapeutically beneficial, particularly by exhibiting chemopreventive activities. In our current research, we have focused on the development of an AHR antagonist using a chemical genetic approach called PROTACS (PROteolysis-TArgeting Chimeric moleculeS).

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The major estrogen metabolite 2-methoxyestradiol (2ME) has been shown to target tumor cells without severe side effects and is currently being evaluated in clinical trials for several types of cancer. Despite its promise for use in clinical setting, the mechanism(s) by which 2ME exerts its anti-tumor activity is not clearly defined at this time. Employing organic chemistry tools, we synthesized 2ME analogs with which 2ME affinity column was prepared, enabling us to detect a protein that selectively interacts with 2ME.

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Small molecules designed to specifically activate or inactivate protein functions have been useful to study biological processes. PROTACS are small molecule chimera which comprise a ligand and a peptide recognition motif for an E3 ligase. These novel reagents exploit the ubiquitin-mediated proteasome degradation pathway to target the ligand-bound protein for intracellular degradation.

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