Lonicera japonica THUNB. Extract Inhibits Lipopolysaccharide-Stimulated Inflammatory Responses by Suppressing NF-κB Signaling in BV-2 Microglial Cells

권승환,MASHIXUN,홍사익,이석용,장춘곤 한국식품영양과학회 2015 Journal of medicinal food Vol.18 No.7

In the current study, we evaluated the anti-inflammatory effects of Lonicera japonica THUNB. (LJ) and its underlying molecular mechanism in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. Our results indicated that LJ significantly inhibits LPS-stimulated production of nitric oxide (NO) and prostaglandin E2 (PGE2). In addition, LJ inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at both the protein and mRNA levels. In LPSstimulated BV-2 microglial cells, LJ inhibited proinflammatory cytokines and chemokines, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinase-9 (MMP-9) enzymatic activities, and/or mRNA expression, as well as reactive oxygen species (ROS) production. LJ significantly suppressed activation of nuclear factor-κB (NF-κB) and its translocation from the cytosol to the nucleus and suppressed the DNA-binding activity of NF-jB. Furthermore, LJ significantly inhibited phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signalregulated kinase 1/2 (ERK 1/2), p38 mitogen-activated protein kinases (MAPKs), phosphatidylinositol 3-kinases (PI3K)/Akt, and Janus kinase 1 (JAK1)/signal transducer and activator of transcription (STAT)1/3. Collectively, our findings indicated that the antineuroinflammatory properties of LJ in LPS-induced BV-2 microglial cells is due to downregulation of proinflammatory cytokines and chemokines downstream of inhibition of NF-κB activation.

YbCd2-xMgxSb2 열전 합금의 열전 성능 증대 메커니즘 분석

권승환,김상일,허민수,서원선,노종욱,양희선,김현식 대한금속·재료학회 2023 대한금속·재료학회지 Vol.61 No.3

YbCd2Sb2 is a promising Zintl compound for waste heat recovery applications due to its low thermalconductivity, originating from its complex crystal structure. Many strategies such as alloying or doping havebeen suggested to further reduce the thermal conductivity of YbCd2Sb2 to improve its thermoelectricperformance. However, the effects of alloying or doping on the electronic transport properties of YbCd2Sb2have not been evaluated in detail. Here, previously reported thermoelectric properties of YbCd2-xMgxSb2 (x =0, 0.2, 0.4) with drastic thermal conductivity suppression were evaluated using the Single Parabolic Band(SPB) model and Callaway von Bayer (CvB) model. The SPB and CvB models evaluate any changes inelectronic band parameters and phonon scattering strength, respectively, due to Mg alloying. Based on theSPB model, Mg alloying deteriorated the weighted mobility, mostly due to non-degenerate mobility reduction. However, the magnitude of point-defect phonon scattering significantly increased with Mg alloying, asevaluated by the CvB model. As a result, the maximum zT is achieved when x = 0.4 at 700 K despite thedecreased electronic transport properties from Mg alloying. Our work suggests that carefully designed alloyingcan improve the thermoelectric performance of the Zintl compound even when it changes its electronic andthermal transport properties in opposite directions.

Vaccinium bracteatum Thunb. Exerts Anti-Inflammatory Activity by Inhibiting NF-κB Activation in BV-2 Microglial Cells

권승환,MASHIXUN,고용현,서지연,이보람,이택환,김선여,이석용,장춘곤 한국응용약물학회 2016 Biomolecules & Therapeutics(구 응용약물학회지) Vol.24 No.5

This study was designed to evaluate the pharmacological effects of Vaccinium bracteatum Thunb. methanol extract (VBME) on microglial activation and to identify the underlying mechanisms of action of these effects. The anti-inflammatory properties of VBME were studied using lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. We measured the production of nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase (COX)-2, prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6) as inflammatory parameters. We also examined the effect of VBME on intracellular reactive oxygen species (ROS) production and the activity of nuclear factor-kappa B p65 (NF-κB p65). VBME significantly inhibited LPS-induced production of NO and PGE2 and LPS-mediated upregulation of iNOS and COX-2 expression in a dosedependent manner; importantly, VBME was not cytotoxic. VBME also significantly reduced the generation of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-6. In addition, VBME significantly dampened intracellular ROS production and suppressed NF-κB p65 translocation by blocking IκB-α phosphorylation and degradation in LPS-stimulated BV2 cells. Our findings indicate that VBME inhibits the production of inflammatory mediators in BV-2 microglial cells by suppressing NF-κB signaling. Thus, VBME may be useful in the treatment of neurodegenerative diseases due to its ability to inhibit inflammatory mediator production in activated BV-2 microglial cells.

공공서비스 제공을 위한 빅데이터 플랫폼 기반 서비스 연구 :전기안전분야를 중심으로

권승환,정덕훈 국제e-비즈니스학회 2019 e-비즈니스 연구 Vol.20 No.5

This paper aims to propose a platform model and service types for public safety services. Recent emergencies and disasters have raised national attention to the need for public safety services. More complex electrical accidents, such as electrical fire accidents, increase the risk of electrical safety. In addition, the greater the magnitude of the damage, the greater the public's interest in electrical safety. This study presents a model of a big data platform that collects, connects, stores, processes, and analyzes a variety of electrical safety-related and emergency-related information to provide electrical safety services. Types of electrical safety services include customer care, safety management, data collection, data evaluation, visualization, and electrical safety services. It also presents a model for public agencies to leverage public data to deliver services such as public safety portals, open safety data, emergency collaboration, and emergency cloud services. 본 논문은 공공안전에 필요한 서비스 구축을 위하여 플랫폼의 모델과 서비스 유형을 제안하는 논문이다. 최근 재난 발생에 따른 피해가 사회적 문제가 대두됨에 따라 안전한 삶을 위한 공공서비스에 대한 국민들의욕구가 커지고 있다. 본 논문에서는 전기안전 분야 또한 전기화재 등 재난의 대형화, 복합화로 사회 전반의전기안전 위험이 증가하고 있으며, 피해 규모도 대형화되어 전기안전 분야에 대한 국민적 관심도가 매우높아지는 실정이다. 본 연구는 각종 전기안전 정보 및 재난안전 유관정보를 플랫폼 기반으로 수집·연계, 저장, 처리, 빅데이터 분석을 통해 전기안전 서비스 제공하기 위한 전기안전 빅데이터 플랫폼의 개념 모델을제시하였다. 전기안전 플랫폼을 활용한 전기안전 서비스 유형으로 플랫폼의 고객, 안전관리 업무, 데이터수집, 데이터 평가, 평가결과 가시화, 전기안전 서비스 제공 등 단계별 시스템 운용을 통해 공공데이터를보유하고 있는 공공기관이 대국민 안전 포털, 안전 데이터 개방, 재난안전 협업, 재난안전 클라우드 서비스제공으로 확대 할 수 있는 모델을 제시한다.

Debye-Callaway 모델 기반 Yb(Cd1-xMgx)2Sb2 열전 합금의 격자 열전도도 분석

허민수,권승환,서원선,김상일,김현식 대한금속·재료학회 2023 대한금속·재료학회지 Vol.61 No.8

YbCd2Sb2-based Zintl phases have been identified as promising materials for thermoelectricapplications due to their high Seebeck coefficient and electrical conductivity. However, their high thermalconductivity limits their overall thermoelectric performance. To address this, Mg has recently been introducedas an alloying element at Cd atomic sites to reduce the lattice thermal conductivity of YbCd2Sb2. Zhang etal. have reported a high zT (a figure-of-merit for the thermoelectric performance) of 1.4 at 700 K inYb(Cd0.8Mg0.2)2Sb2. They have demonstrated that the high zT is due to significantly suppressed phonontransport, in other words, low lattice thermal conductivity. They attributed the significantly low latticethermal conductivity to severely distorted lattices that could not be described even with the Debye-Callawaymodel. Here, the Debye-Callaway model and Callaway-von Baeyer model have been utilized to evaluate theeffect of Mg alloying on the lattice thermal conductivity of Yb(Cd1-xMgx)2Sb2 (x = 0, 0.1, 0.2) by estimating theirtheoretical lattice thermal conductivities. We found that appropriately fitting the parameter included in thephonon relaxation rate (of the Debye-Callaway model), which represents a fractional change of bulk modulusto that of local bond length, could describe the significantly suppressed lattice thermal conductivities ofYb(Cd1-xMgx)2Sb2 (x = 0, 0.1, 0.2).

재사용 우주비행체 멀티스케일 삭마 해석 기법 연구

안종경(Jongkyung An),권승환(Seunghwan Kwon),안지선(Jiseon Ahn),윤군진(Gun Jin Yun) 한국항공우주학회 2023 한국항공우주학회 학술발표회 논문집 Vol.2023 No.11