표면개질된 나노실리카의 충진함량에 따른 Epoxy Nano Composites의 HVDC 및 HVAC 전기적 절연파괴 특성

승오탁(O-Tak Seung),박재준(Jae-Jun Park) 대한전기학회 2019 전기학회논문지 Vol.68 No.11

In this study, the surface of nano silica was modified to improve the insulation characteristics of high voltage based heavy electric equipment. The surface-modified nanosilica was homogeneously dispersed by filling the epoxy resin with different contents (0,1,3,5,7,9phr) and Epoxy / Nano Silica Composites were prepared. The glass transition temperature was determined for the homogeneous dispersion of surface-modified nanoparticles, and for evaluation of interfacial and thermal properties. Short-term HVDC positive polarity breakdown and HVAC breakdown characteristics were evaluated as electrical insulation performance improvement. Also, for the long-term reliability evaluation, the AC electrical tree characteristic was evaluated under inequality by frequency acceleration degradation method. The glass transition temperature increased with the increase of the content of nano-silica surface-modified on the epoxy resin, and the dielectric breakdown strength increased with the filling content of HVDC insulation breakdown and decreased with HVAC. Moreover, the insulation life decreased with the increase of the filling content in the long time electric tree experiment.

에폭시/실리카 콤포지트의 수분 흡수 및 건조에 따른 전기적 유전특성에 관한 연구

승오탁(O-Tak Seung) 대한전기학회 2021 전기학회논문지 Vol.70 No.9

Epoxy-based microcomposites are currently used in a variety of high-voltage-based heavy electric machines (CT/PT, mold transformers, distribution insulators, etc.). Samples were prepared with three types of micro-silica-filled composites (W12est_65wt%, M10_65wt%) and epoxy prototype samples based on epoxy resin. The moisture absorption and drying properties of the three samples were evaluated. The moisture absorption process was performed until the moisture absorption of the sample was saturated in distilled water at 95°C, and the drying process was performed in a drying oven at 105°C until the moisture was saturated without any change. In the evaluation, the relationship between water absorption (M) and dielectric properties was evaluated under the conditions of steady state, moisture absorption and dry conditions. And dielectric characteristics (dielectric constant, dielectric loss and electrical conductivity) were evaluated according to the frequency change at room temperature as an evaluation environment. A large amount of water absorption resulted in a large increase in dielectric constant, dielectric loss, and electrical conductivity. In addition, it was found that the dielectric properties were restored because the dry state was based on the physical bonding with the absorbed water.

PC12와 BV2 세포에서 동충하초 추출물의 인지능력 개선 효과

최순희,승오탁,이명선,Choi, Soon-Hee,Seung, O-Tak,Lee, Myung-Sun 한국응용과학기술학회 2019 한국응용과학기술학회지 Vol.36 No.2

본 연구는 동충하초 추출물을 PC12 및 BV2 세포에서 인지능력 개선에 대한 효능을 평가하고자 하였다. 동충하초 추출물을 증류수로 추출하여 PC12 및 BV2 세포로 MTT 분석을 통해 세포 생존율을 확인하고 L-glutamate로 유도한 PC12 세포를 통해 세포 보호 효능과 아세틸콜린 함량 및 아세틸콜린에스테아제 활성을 평가하였다. 또한, LPS로 유도한 BV2 세포를 통해 nitric oxide (NO) 및 prostaglandin E2 (PGE2) 생성량 등의 항염증 효능을 측정하고 western blot 분석을 통해 $NK-{\kappa}B$, p38, JNK, caspase-3 등의 단백질 발현량을 확인하였다. 동충하초 추출물은 $200{\mu}g/m{\ell}$ 농도를 제외하고 1, 10, $100({\mu}g/m{\ell})$ 농도에서 세포 독성이 나타나지 않았다. L-glutamate로 유도한 PC12 세포에서 유의성있게 세포 보호 효능과 아세틸콜린 함량의 증가, 아세틸콜린에스테아제 활성 감소가 나타났다. 또한, 동충하초 추출물은 NO 및 PGE2 생성량과 $NK-{\kappa}B$, p38, JNK, caspase-3 등의 단백질 발현을 억제하였다. 이와 같은 결과는 동충하초 추출물이 인지능력에 대한 예방 및 개선 효능이 있음을 나타낸다. 따라서 동충하초 추출물은 인지능력 개선을 위한 새로운 천연 소재로 활용될 수 있다. The aim of this study is to evaluate the efficacy of cordyceps militaris extracts for the improvement of cognitive dysfunction in PC12 and BV2 cells. Cordyceps militaris extracts was prepared by extracting with distilled water. Cell viability was assessed by MTT assay using PC12 cells and BV2 cells. Confirmed effects of L-glutamate induced cytotoxicity test, Acetylcoline (ACh) concentration, and Acetylcolinestase (AChE) activity in PC12 cells. Anti-inflammatory activities of cordyceps militaris extracts was measured through changes in the levels of nitric oxide (NO), and prostaglandin E2 ($PGE_2$) on lipopolysaccharide(LPS)-induced BV2 cell. In addition, we measured the expression of $NF-{\kappa}B$, p38, JNK, and caspase-3 in western blot analysis. Cordyceps militaris extracts showed no cytotoxicity at the concentrations of 1, 10, and $100{\mu}g/m{\ell}$ except for the concentration of $200{\mu}g/m{\ell}$. Cordyceps militaris extracts protected the cell and exhibited significant increases in the ACh concentration and a significant decrease in the AChE activity in L-glutamate induced PC12 cells. Moreover, cordyceps militaris extracts inhibited the productions NO, and PGE2 level and the protein expression of $NF-{\kappa}B$, p38, JNK, caspase-3 in LPS-induced BV2 cells. These results indicate that cordyceps militaris extracts possible prevented and improved cognitive dysfuction symptoms. Thus, cordyceps militaris extracts may be a novel natural material option for the improvement of cognitive dysfunction.

지골피 추출물이 류마티스관절염 관련 매개체에 미치는 영향

장아영,승오탁,이명선 한국응용과학기술학회 2019 한국응용과학기술학회지 Vol.36 No.4

The present study aimed to evaluate the effect of Lycii radicis CORTEX extract on rheumatoid related factors in CIA-induced Rheumatoid Arthritis model of DBA/1 mice. Lycii radicis CORTEX extract was administered orally at doses of 200 mg/kg/day for 4 weeks after direct injection of CIA into the mice’ right paw. We evaluated the treatment effects based on serum biomarkers, morphological and histopathological analyses of the paw. Compared with those in control mice, the Lycii radicis CORTEX extract treatments significantly reduced the serum concentration of cytokine, kemokine and immunoglobulin levels. In addition, the Lycii radicis CORTEX extract treatments effectively preserved the paw bone joint, that in the H&E staining and masson-trichrome staining showed that there were histopathological improvements in Lycii radicis CORTEX extract treated group compared to those of control group. The results indicate that Lycii radicis CORTEX extract alleviated rheumatoid arthritis symptoms. Thus, Lycii radicis CORTEX extract may be a novel therapeutic option for the management of rheumatoid arthritis. 본 연구는 CIA로 유도된 류마티스 관절염 모델에서 지골피 추출물이 류마티스관절염 관련 인자에 미치는 영향을 평가하였다. 동물 모델에 류마티스관절염을 유발한 후 지골피 추출물을 4주간 200 ㎎/㎏/day 용량으로 경구 투여하였다. 이후 혈액, 방사선 및 조직 분석에 기초하여 효과를 평가하 였다. 그 결과, 대조군에 비해 지골피 추출물은 사이토카인, 케모카인 및 면역글로불린 생성을 유의하게 감소시켰다. 또한, 지골피 추출물은 중족골을 효과적으로 보존하였으며, H&E 및 M&T 염색에서도 대조군에 비해 조직 병리학적 개선이 있음을 보여주었다. 이와 같은 결과는 지골피 추출물이 류마티스관절염 증상을 완화시켰음을 나타내고 있다. 따라서 지골피 추출물은 류마티스 관절염 관리를 위한 새로운 치료옵션이 될 수 있다.

열수 및 80% 에탄올로 추출한 박하의 생리활성 비교연구

최동훈,승오탁,임미혜 한국응용과학기술학회 2019 한국응용과학기술학회지 Vol.36 No.1

The purpose of this study was to investigated the biological activities such as cytotoxic, anti-oxidant and anti-inflammatory using Mentha arvensis L. extracts. Mentha arvensis L. was prepared by extracting with DW and 80% ethanol, after cell viability was assessed by MTT assay using RAW 264.7 cells. Antioxidant activities, and Anti-inflammatory activities measured through changes in the levels of reactive oxygen species (ROS), nitric oxide (NO), leukotrien B4 (LTB4), and anti- or in-flammatory cytokines(IL-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-10) on LPS-induced RAW 264.7 cells. All test measured by ELISA reader and Luminex. Mentha arvensis L. was no cytotoxic in water and 80% ethanol extracts, and Concentration of 100 ug/ml of 80% ethanol extract was suppressed the productions of ROS in LPS-induced RAW 264.7 cells. Also, Productions of NO, LTB4, inflammatory or anti-inflammatory cytokines showed efficacy change that dose-independent of all extracts. In other words, Mentha arvensis L. showed significant biological activities showing anti-inflammatory, and anti-oxidant. These results may be developed as a raw material for new health food and therapeutics to ease the symptoms mentioned above. 본 연구는 박하 추출물을 통해 독성검사 및 항산화, 항염증과 같은 생리활성을 평가하고자 하였다. 박하 추출은 열수 및 80% 에탄올로 추출하였으며, RAW 264.7 세포를 통해 MTT를 통해 세포 생존율을 평가하였다. 또한, LPS로 유도한 RAW 264.7 세포를 통해 활성산소(ROS), 산화질소(NO), 류코트리엔 B4(LTB 4 ), 항염 또는 염증성 사이토카인(IL-1β, IL-6, TNF-α, IL-10) 등을 ELISA 및 Luminex로 측정하였다. 그 결과, 박하 추출물은 열수 및 80% 에탄올 추출물에서 세포독성이 없었으며, 80% 에탄올 추출물의 100 ㎍/㎖ 농도에서 활성산소의 생성을 억제하였다. 또한, NO, LTB4, 염증 또는 항염증성 사이토카인의 생성을 모든 추출물에서 농도 의존적 효능을 나타냈다. 즉, 박하 추출물은 세포 독성 없이 항산화 및 항염증 활성을 나타내는 생리학적 효능이 나타났다. 이와 같은 결과는 본 연구와 관련된 증상을 개선하기 위한 새로운 건강식품 및 치료제의 원료로 개발될 수 있다.