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Comparative molecular docking studies of lupeol and lupenone isolated from Pueraria lobata that inhibits BACE1: Probable remedies for Alzheimer's disease

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Asian Pacific Journal of Tropical Medicine 2017年第12期10卷 1117-1122页

作者： Prashamsa Koirala Su Hui Seong hyun Ah Jung Jae Sue choi Department of Food and Life Science Pukyong National University Department of Food Science and Human Nutrition Chonbuk National University

Objective: To discover lead lupane triterpenoid's potential isolated from Pueraria lobata roots against b-site amyloid precursor protein cleaving enzyme 1(BACE1), which serve as a rate limiting step in amyloid beta(Aβ) production altering the course of Alzheimer's disease. In addition, enzyme kinetics study and molecular docking were conducted to establish the inhibition type and structure activity ***: A systematic study of 70% ethanolic P. lobata root extract was employed to identify its BACE1 inhibitory potential. Further, BACE1 inhibitory potential of two lupane terpenoids, yielded from ethanolic extract, was assessed. In order to determine their inhibition mode, Lineweaver–Burk plots and michaelis–Menten model for BACE1 was performed. Auto Dock 4.2 program in addition determined the molecular interaction of BACE1 with isolated ***: Considering the inhibitory potential of 70% ethanolic extract of P. lobata against BACE1(IC_(50)= 80.35 mg/mL), lupeol and lupenone were subsequently isolated and exhibited notable or moderate BACE1 inhibitory activity with IC_(50) values of 5.12 and 62.98 mmol/L, respectively, as compared to the positive control quercetin(IC_(50)= 21.28 mmol/L). The enzyme kinetics study enabled us to identify both compounds as competitive inhibitors, where lupeol displayed a very potent inhibition against BACE1 with low inhibition constant(Ki) value of 1.43 mmol/L, signifying greater binding *** order to understand the binding mechanism and structure–activity relationship of two triterpene-based BACE1 inhibitors, we employed computer aided docking studies which evidently revealed that hydroxyl group of lupeol formed two hydrogen bonds with the ASP32(catalytic aspartic residue) and SER35 residues of BACE1 with the binding energy of(-8.2 kcal/mol), while the ketone group of lupenone did not form any hydrogen bonds with BACE1 giving evidence for less binding affinity. These results in turn have predicted the dep

关键词： Pueraria lobata BACE1 Lupeol Lupenone Molecular docking Kinetics

Contact surface fatigue life for roller rack pinion system

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Journal of Central South University 2012年第12期19卷 3454-3459页

作者： KIM Chang-hyun choi Heung-soap KWON Soon-man Department of Mechanical Design and Manufacturing Engineering Changwon National UniversityChangwon 641-773Korea Department of Mechano-Informatics and Design Engineering Hongik UniversitySejong 339-701Korea

A roller rack pinion(RRP)system,which consists of a rack-bar and a cam pinion,transforms a rotation motion into linear *** rack-bar has a series of roller train and meshes with the cam ***,the exact tooth profile of the cam pinion and the non-undercut condition to satisfy the required performance have been proposed with the introduction of the profile shift ***,the load stress factors are investigated under the variation of the shape design parameters to predict the gear surface fatigue limit which is strongly related to the gear noise and vibration at the contact *** results show that the pitting life can be extended significantly with the increase of the profile shift coefficient.

关键词： roller rack pinion profile shift coefficient load stress factor pitting life

Unlocking power of neighboring vacancies in boosting hydrogen evolution reactions on two-dimensional NiPS3 monolayer

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eScience 2024年第3期4卷 104-115页

作者： hyun Gu Han Jae Won choi minsu Son Ki Chul Kim Computational Materials Design Laboratory Department of Chemical EngineeringKonkuk UniversitySeoul 05029The Republic of Korea Division of Chemical Engineering Konkuk UniversitySeoul 05029The Republic of Korea

This study investigates the effect of defect engineering on the catalytic activity of a NiPS3 monolayer catalyst for the hydrogen evolution reaction(HER).Three different types of vacancies on the basal plane of the monolayer are explored through a multi-step mechanism involving the dissociative adsorption of a water molecule and subsequent electrochemical adsorption of the dissociated ***-formation of vacancies in both Ni and S sites is found to be the most effective in enhancing the catalytic performance of the monolayer.A key resource for the reaction thermodynamics is the S-substitution-like physisorption of a water molecule on a vacant S site,followed by the dissociative occupation of OH and H into vacant sites of S and Ni elements,boosted by the NiS di-vacancy configuration with low activation energy *** reveals the highest contribution of bonding orbitals to the monolayer-H bond makes it the most desirable defect engineering approach for transition metal phosphorus chalcogenides with high HER ***,this study highlights the significance of controlled defect engineering in augmenting the catalytic performance of NiPS3 monolayer catalysts for HER.

关键词： Hydrogen evolution reaction Defect engineering Transition metal phosphorus trichalcogenide Density functional theory Reaction thermodynamics

Tacrolimus for children with refractory nephrotic syndrome:a one-year prospective,multicenter,and open-label study of Tacrobell®,a generic formula

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World Journal of Pediatrics 2016年第1期12卷 60-65页

作者： Eun mi Yang Sang Taek Lee hyun Jin choi Hee Yeon Cho Joo Hoon Lee Hee Gyung Kang Young Seo Park Hae Il Cheong Il-Soo Ha Department of Pediatrics Chonnam National University HospitalGawngjuKorea Department of Pediatrics Seoul National University Children's HospitalSeoulKorea Department of Pediatrics Samsung Medical CenterSungkynkwan University School of MedicineSeoulKorea Department of Pediatrics Asan Medical Center Children's HospitalUniversity of Ulsan College of MedicineSeoulKorea Research Coordination Center for Rare Diseases Seoul National University HospitalSeoulKorea Kidney Research Institute Medical Research CenterSeoul National University College of MedicineSeoulKorea

Background:Cyclosporine A and tacrolimus(TAC)are often used as a second-line treatment for children with refractory nephrotic syndrome(NS).This study was undertaken to investigate the efficacy and safety of Tacrobell®,a locally produced generic form of ***:This study was a one-year prospective,open-label,single-arm,multicenter ***-four children with steroid-dependent NS(SDNS)and 33 children with steroid-resistant NS(SRNS)were *** primary endpoints were defined as the remission rates,whereas the secondary endpoints were recognized as the duration of remission and adverse effects of ***:After one-year treatment,34(77.3%)of the 44 patients with SDNS were in complete remission,and 6(13.6%)were in partial ***(43.2%)patients did not relapse during the study;for those who did relapse,the mean duration of remission was 4.6±2.9 *** number of relapse episodes during the study period(0.90 per patient-year)was significantly lower than that in the preceding year(2.8 per patientyear).After treatment for 3 and 6 months,12(36.4%)of the 33 patients with SRNS were in remission,and after treatment for 12 months,the number of patients had increased to 13(39.4%).The mean time to achieve remission was 4.0±3.2 *** remission(duration,3.7±2.7 months),12(54.5%)of 22 patients *** fasting blood glucose and blood pressure levels during the therapy were similar to those at the time of study ***:Treatment with Tacrobell®was effective and safe for children with refractory *** efficacy of this generic form of TAC was better than that of the original TAC formula.

关键词： generic drugs nephrotic syndrome tacrolimus

Anticancer effects of oligomeric proanthocyanidins on human colorectal cancer cell line, SNU-C4

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World Journal of Gastroenterology 2005年第30期11卷 4674-4678页

作者： Youn-Jung Kim Hae-Jeong Park Seo-hyun Yoon mi-Ja Kim Kang-hyun Leem Joo-Ho Chung Hye-Kyung Kim Department of Dental Hygiene Department of Pharmacology Department of Obesity Management College of Oriental Medicine Department of Food and Biotechnology

AIM: Oligomeric proanthocyanidins (OPC), natural polyphenolic compounds found in plants, are known to have antioxidant and anti-cancer effects. We investigated whether the anti-cancer effects of the OPC are induced by apoptosis on human colorectal cancer cell line, ***: Colorectal cancer cell line, SNU-C4 was cultured in RPmi 1640 medium supplemented with 10% fetal bovine serum. The cytotoxic effect of OPC was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenylt-etrazolium bromide (MTT) assay. To find out the apoptotic cell death, 4, 6-diamidino-2-phenylindole (DAPI) staining,terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, reverse transcriptionpolymerase chain reaction (RT-PCR), and caspase-3 enzyme assay were ***: In this study, cytotoxic effect of OPC on SNUC4 cells appeared in a dose-dependent manner. OPC treatment (100 μg/mL) revealed typical morphological apoptotic features. Additionally OPC treatment (100 μg/mL)increased level of BAX and CASPASE-3, and decreased level of BCL-2 mRNA expression. Caspase-3 enzyme activity was also significantly increased by treatment of OPC (100 μg/mL) compared with ***: These data indicate that OPC caused cell death by apoptosis through caspase pathways on human colorectal cancer cell line, SNU-C4.

关键词： Oligomeric pranthocyanidins Apoptosis Anticancer effects Colorectal cancer

Cardiac metastasis from colorectal cancer:A case report

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World Journal of Gastroenterology 2009年第21期15卷 2675-2678页

作者： Pyong Wha choi Chul Nam Kim Sun Hee Chang Woo Ik Chang Chang Young Kim hyun min choi Department of Surgery Ilsan Paik HospitalInje University College of Medicine Department of Diagnostic Pathology Ilsan Paik HospitalInje University College of Medicine Department of Chest Surgery Ilsan Paik HospitalInje University College of Medicine Department of Internal Medicine Ilsan Paik HospitalInje University College of Medicine

The heart is an unusual site of metastasis from any malignancy. We report a case of cardiac metastasis from colorectal cancer. A 70-year-old woman was referred with a presumptive diagnosis of sigmoid colon cancer with cardiac myxoma. Two-dimensional echocardiography showed a 4 cm x 4.5 cm mobile mass on the lateral right atrial wall, and computed tomography revealed a low attenuated Iobulating mass in the right atrium. The patient underwent anterior resection for sigmoid colon cancer （T4N2）. Thereafter, she experienced progressive shortness of breath. Therefore, a cardiac operation was performed 2 wk after the colorectal operation. Histological examination revealed adenocarcinoma, which was identical to the primary lesion. Although two- dimensional echocardiography has become the diagnostic test of choice for detecting cardiac tumors, in patients with colorectal cancer showing a cardiac mass, further diagnostic evaluation such as a magnetic resonance imaging might be necessary.

关键词： Heart Cardiac metastasis Colorectalcancer Atrial myxoma Magnetic resonance imaging

Anti-Alzheimer's disease potential of coumarins from Angelica decursiva and Artemisia capillaris and structure-activity analysis

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Asian Pacific Journal of Tropical Medicine 2016年第2期9卷 101-108页

作者： Md.Yousof Ali Susoma Jannat hyun Ah Jung Ran Joo choi Anupom Roy Jae Sue choi Department of Food and Life Science Pukyong National University Department of Food Science and Human Nutrition Chonbuk National University Angiogenesis& Chinese Medicine Laboratory Department of Pharmacology University of Cambridge

Objective: To use structure-activity analysis to study the anti-Alzheimer's disease(anti-AD) activity of natural coumarins isolated from Angelica decursiva and Artemisia capillaries, along with one purchased coumarin(daphnetin). Methods: Umbelliferone, umbelliferone 6-carboxylic acid, scopoletin, isoscopoletin, 7-methoxy coumarin, scoparone, scopolin, and esculetin have been previously isolated; however 2'-isopropyl psoralene was isolated from Angelica decursiva for the first time to evaluate their inhibitory effects against acetylcholinesterase(ACh E), butyrylcholinesterase(BCh E), and β-site amyloid precursor protein cleaving enzyme 1(BACE1) enzyme activity. We scrutinized the potentials of coumarins as cholinesterase and BACE1 inhibitors via enzyme kinetics and molecular docking simulation. Results: Among the test compounds, umbelliferone 6-carboxylic acid, esculetin and daphnetin exhibited potent inhibitory activity against ACh E, BCh E and BACE1. Both esculetin and daphnetin have a catechol group and exhibit significant anti-AD activity against ACh E and BCh E. In contrast, presence of a sugar moiety and methoxylation markedly reduced the anti-AD activity of the coumarins investigated in this study. With respect to BACE1 inhibition, umbelliferone 6-carboxylic acid, esculetin and daphnetin contained carboxyl or catechol groups, which significantly contributed to their antiAD activities. To further investigate these results, we generated a 3D structure of BACE1 using Autodock 4.2 and simulated binding of umbelliferone 6-carboxylic acid, esculetin and daphnetin. Docking simulations showed that different residues of BACE1 interacted with hydroxyl and carboxylic groups, and the binding energies of umbelliferone 6-carboxylic acid, esculetin and daphnetin were negative(-4.58,-6.25 and-6.37 kcal/mol respectively). Conclusions: Taken together, our results suggest that umbelliferone 6-carboxylic acid, esculetin and daphnetin have anti-AD effects by inhibiting ACh E, BCh

关键词： Umbelliferone 6-carboxylic acid Esculetin Daphnetin Coumarins Cholinesterase BACE1

Topology optimization of reactive material structures for penetrative projectiles

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Defence Technology（防务技术） 2022年第7期18卷 1205-1218页

作者： Shinyu Kim Saekyeol Kim Taekyun Kim Sangin choi Tae Hee Lee Jung Su Park Sang-hyun Jung Department of Automotive Engineering Hanyang University222 Wangsimni-roSeongdong-guSeoul04763Republic of Korea The 4th R&D Institute Agency for Defense Development35Yuseong P.O.BoxDaejeon34186Republic of Korea

Recently,reactive materials have been developed for penetrative projectiles to improve impact resistance and energy ***,the design of a reactive material structure,involving shape and size,is challenging because of difficulties such as high non-linearity of impact resistance,manufacturing limitations of reactive materials and high expenses of penetration *** this study,a design optimization methodology for the reactive material structure is developed based on the finite element analysis.A finite element model for penetration analysis is introduced to save the expenses of the *** resistance is assessed through the analysis,and result is calibrated by comparing with experimental *** on the model,topology optimization is introduced to determine shape of the *** design variables and constraints of the optimization are proposed considering the manufacturing limitations,and the optimal shape that can be manufactured by cold spraying is *** on the optimal shape,size optimization is introduced to determine the geometric dimensions of the *** a result,optimal design of the reactive material structure and steel case of the penetrative projectile,which maximizes the impact resistance,is *** the design process proposed in this study,reactive material structures can be designed considering not only mechanical performances but also manufacturing limitations,with reasonable time and cost.

关键词： Reactive material Penetrative projectile Topology optimization Manufacturing constraint Cold gas dynamic spray Additive manufacturing

Gradient Si-and Ti-doped Fe_(2)O_(3) hierarchical homojunction photoanode for efficient solar water splitting:Effect of facile microwave-assisted growth of Si-FeOOH on Ti-FeOOH nanocorals

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Journal of Energy Chemistry 2023年第2期77卷 27-37,I0002页

作者： Tae Sik Koh Periyasamy Anushkkaran Weon-Sik Chae hyun Hwi Lee Sun Hee choi Jum Suk Jang Division of Biotechnology College of Environmental and Bioresource SciencesJeonbuk National UniversityIksan 54596Republic of Korea Daegu Center Korea Basic Science InstituteDaegu 41566Republic of Korea Pohang Accelerator Laboratory Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea

The construction of a homojunction is an effective approach for addressing issues such as slow charge separation and charge-transfer kinetics in *** the present work,we designed a gradient Si-and Ti-doped Fe_(2)O_(3) homojunction photoanode to improve the photoelectrochemical(PEC)performance of a Ti-doped Fe_(2)O_(3) ***-FeOOH nanocorals were synthesized using a hydrothermal process,and Si-FeOOH was grown on Ti-FeOOH nanocorals using a rapid and facile microwaveassisted(MW)*** varying the MW irradiation time,the thickness of the Si/Ti:Fe_(2)O_(3) photoanode was adjusted and an optimized 3-Si/Ti:Fe_(2)O_(3) photoelectrode was achieved with a significantly enhanced photocurrent density(1.37 mA cm^(-2) at 1.23 V ***)and a cathodic shift of the onset potential(150 mV)compared with that of bare Ti-Fe_(2)O_(3).This enhanced PEC performance can be ascribed to homojunction formation and Si gradient *** Si dopant increased the donor concentration and the formation of a homojunction improved the intrinsic built-in electric field,thereby promoting charge separation and charge ***,the as-formed homojunction passivated the surfacetrapping states,consequently improving the charge transfer efficiency(60%at 1.23 VRHE)at the photoanode/electrolyte *** findings could pave the way for the microwave-assisted fabrication of diverse efficient homojunction photoanodes for PEC water splitting applications.

关键词： Homojunction microwave-assisted Hematite Gradient doping PEC water splitting