• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.93-93
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• 2018

This study disclosed the aqueous fruits extract of Rubus coreanus as a sustainable agent for the synthesis of Rubus coreanus zinc oxide nanoparticle (Rc-ZnO Nps) using as a reducing and capping precursor for co-precipitation method. The development of Rc-ZnO was assured by white precipitated powder and analyzed by spectroscopic and analytical instruments. The UV-visible (UV-Vis) studies indicate the maximum absorbance at 357nm which confirmed the formation of ZnO Nps and the purity, functional group and monodispersity were assured by field emission transmission electron microscopy (FE-TEM), Fourier Transform Infrared (FTIR) Spectroscopy and dynamic light scattering (DLS). The X-ray powder diffraction (XRD) data revealed the Nps is 23.16 nm in size, crystalline in nature and possess hexagonal wurtzite structure. The Rc-ZnO Nps were subjected for catalytic studies. The Malachite Green dye was degraded by Rc- ZnO NPs in both dark and light (100 W tungsten) conditions and it degraded about 90% at 4 hours observation in both cases. The biodegradable, low cost Rc-ZnO NPs can be a better weapon for waste water treatment.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.68-68
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• 2018

In this study, we investigated whether S. baicalensis rhizome ethanol extract (SBRE) has antioxidant capacities against oxidative stress induced cellular damage in the HaCaT keratinocytes. Our results revealed that treatment with SBRE prior to hydrogen peroxide ($H_2O_2$) exposure significantly increased the HaCaT cell viability. SBRE also effectively attenuated $H_2O_2$ induced comet tail formation, and inhibited the $H_2O_2$ induced phosphorylation levels of the histone ${\gamma}H2AX$, as well as the number of apoptotic bodies and Annexin V positive cells. In addition, SBRE exhibited scavenging activity against intracellular ROS generation and restored the mitochondria membrane potential loss induced by $H_2O_2$. Moreover, $H_2O_2$ enhanced the cleavage of caspase-3 and degradation of poly (ADP-ribose)-polymerase as well as DNA fragmentation; however, these events were almost totally reversed by pretreatment with SBRE. Furthermore, SBRE increased the levels of HO-1 associated with the induction of Nrf2. Therefore, we believed that SBRE may potentially serve as an agent for the treatment and prevention of neurodegenerative diseases caused by oxidative stress.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3767-3771
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• 2012

In this study, we investigate the potential use of $TiO_2@SiO_2$ and $ZnO@SiO_2$ core/shell nanoparticles (NPs) as effective UV shielding agent. In the typical synthesis, $SiO_2$ was coated over different types of $TiO_2$ (anatase and rutile) and ZnO by sol-gel method. The synthesized $TiO_2@SiO_2$ and $ZnO@SiO_2$ NPs were characterized by UV-Vis, XRD, SEM and TEM. The UV-vis absorbance and transmittance spectra of core@shell NPs showed an efficient blocking effect in the UV region and more than 90% transmittance in the visible region. XRD and SAED studies confirmed the formation of amorphous $SiO_2$ coated over the $TiO_2$ and ZnO NPs. The FESEM and TEM images shows that coating of $SiO_2$ over the surface of anatase, rutile $TiO_2$ and ZnO NPs resulted in the increase in particle size by ~30 nm. In order to study the UV light shielding capability of the samples, photocatalytic degradation of methylene blue dye on $TiO_2@SiO_2$ and $ZnO@SiO_2$ NPs was performed. Photocatalytic activity for both types of $TiO_2$ NPs was partially suppressed. In comparison, the photocatalytic activity of ZnO almost vanished after the $SiO_2$ coating.

• International Journal of Oral Biology
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• 제38권3호
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• pp.93-100
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• 2013

Bile acids and synthetic bile acid derivatives induce apoptosis in various kinds of cancer cells and thus have anticancer properties. Recently, it has been suggested that autophagy may play an important role in cancer therapy. However, few data are available regarding the role of autophagy in oral cancers and there have been no reports of autophagic cell death in OSCCs (oral squamous cell carcinoma cells) induced by HS-1200, a synthetic bile acid derivative. We thus examine whether HS-1200 modulates autophagy in OSCCs. Our findings indicate that HS-1200 has anticancer effects in OSCCs, and we observed in these cells that autophagic vacuoles were visible by monodansylcadaverine (MDC)and acridine orange staining. When we analyzed HS-1200-treated OSCC cells for the presence of biochemical markers, we observed that this treatment directly affects the conversion of LC-3II, degradation of p62/SQSTM1 and full-length beclin-1, cleavage of ATG5-12 and the activation of caspase. An autophagy inhibitor suppressed HS-1200-induced cell death in OSCCs, confirming that autophagy acts as a pro-death signal in these cells. Furthermore, HS-1200 shows anticancer activity against OSCCs via both autophagy and apoptosis. Our current findings suggest that HS-1200 may potentially contribute to oral cancer treatment and thus provide useful information for the future development of a new therapeutic agent.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.779-783
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• 2002

변성기용 절연 재료로 사용되는 에폭시 수지를 시료로 선정, 5종의 배합비로 제작한 시편에 대해 절연 파괴 실험을 하며, 얻어진 데이터를 와이블 분포식을 이용, 경년 열화(經年劣和) 데이터의 통계 처리 방법을 제안하였다. 경화제 비율이 증가하면 에폭시 경화물의 에스터화로 인해 가교 밀도가 증가함으로써 저온에서의 파괴 강도가 높아졌으며, 유리 전이 온도(Tg) 영역인 11$0^{\circ}C$ 부근에서는 분자 운동이 활발해짐으로써 급격히 파괴 강도가 저하하였다. 또한, 충진제를 첨가한 경우 접합 계면에 전자가 가속되어 전반적인 파괴 강도는 무충진에 비해 낮게 나타났으며, 실란 처리를 한 경우에는 계면 접합 상태가 개선되어 충진제만을 첨가한 시료보다 좋은 절연성을 나타냈다. 와이블 분포의 분석으로부터 기기 절연의 허용 파괴 확률을 0.1% 이하로 낮추기 위해서는 허용인가 전계값이 21.5 MV/cm 이하가 되어야함을 알 수 있었다.

• Elastomers and Composites
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• 제45권1호
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• pp.12-16
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• 2010

본 연구에서는 에폭시 나노복합재료의 수분 흡수, 열적 안정성 및 기계적 특성에 대한 소수성 실리카의 효과에 대해 고찰하였고, 에폭시 수지의 필러로는 디메틸디크로로실란에 의해 소수성으로 처리된 실리카를 사용하였다. 실험 결과, 실리카는 실란 커플링제의 첨가후 용융혼합법에 의하여 에폭시 수지내에서 균일하게 분산되었으며, 나노복합체의 수분 흡수율은 소수성으로 처리된 실리카의 함량 증가와 함께 감소하는 것을 확인하였다. 열분해 온도, 유리전이 온도, 그리고 열팽창 계수를 통한 나노복합재료의 열안정성은 실리카의 첨가와 함께 향상되는 것을 확인하였다. 또한, 인장강도 및 탄성율을 통한 나노복합재료의 기계적 특성은 실리카 함량 증가와 함께 증가하였고, 이는 에폭시 수지내에 고르게 분산된 실리카와 에폭시 수지 간의 강한 물리적 상호작용에 기인하는 것으로 판단된다.

• Carbon letters
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• 제8권3호
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• pp.184-190
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• 2007

Carbon Nano Tubes could be either metallic or semi-conducting in nature, depending on their diameter. Its photocatalytic behavior has given an impetus to use it as an anti-microbial agent. More than 95% Escherichia coli and Staphylococcus aureus bacteria got killed when exposed to Carbon Nano Tubes for 30 minutes in presence of sunlight. Carbon Nano Tubes are supposed to have smooth surface on to which it accumulates positive charges when exposed to light. The surface that is non illuminated has negative charge. At the cellular level microorganisms produce negative charges on the cell membrane, Therefore damaging effect of multi walled carbon nano tubes (exposed to light) on the microorganisms is possible. In this paper, photo catalytic killing of microbes by multi walled carbon nano tubes is reported. Killing was due to damage in the cell membrane, as seen in SEM micrographs. Moreover biochemical analysis of membrane as well as total cellular proteins by SDS PAGE showed that there was denaturation of membrane proteins as well as total proteins of both the microbes studied. The killed microbes that showed a decrease in number of protein bands (i.e. due to breaking down of proteins) also showed an increase in level of free amino acids in microbes. This further confirmed that proteins got denatured or broken down into shorter units of amino acids. Increased level of free amino acids was recorded in both the microbes treated with multi walled carbon nano tubes and sunlight.

• 동의생리병리학회지
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• 제26권5호
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• pp.738-744
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• 2012

Gastrodia elata Blume is used for a variety of purposes including treatment of inflammation in the Korean medicine. The present study investigated whether the G. elata extracts have the anti-inflammatory effect on lipopolysaccharide(LPS)-stimulated BV-2 microglia cells. G. elata extracts showed an anti-inflammatory effects in the morphological and nitric oxide(NO) analysis, especially in hexane extract. So we investigated the hexane extract from G. elata in the following experiments. Hexane extract significantly inhibited the secretion of NO with protein level of inducible nitric oxide synthase in LPS-stimulated BV2 microglia cells. Hexane extract also inhibited LPS-stimulated inflammatory responses involving the degradation of cytosolic inhibitory(I)-${\kappa}B{\alpha}$ and the translocation of nuclear factor(NF)-${\kappa}Bp65$ to nucleus in LPS-stimulated BV-2 microglia cells by morphological analysis. Western blot analyse confirmed that I-${\kappa}B{\alpha}$ and NF-${\kappa}Bp65$ showed a similar pattern as morphological analysis. Our results suggest that G. elata extracts, especially hexane extract, may act as a therapeutic agent for inflammatory disease in the central nervous system through a selective regulation of NO production and NF-${\kappa}B$ activation.

• 동의생리병리학회지
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• 제21권6호
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• pp.1437-1449
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• 2007

In this study, the effect of extract of Corydalis yanhusuo (ECT) used in Oriental medicine therapy was investigated on the cell growth and apoptosis of HepG2 human hepatoma cells. It was found that ECT could inhibit the cell growth effectively in a dose-dependent manner, which was associated with morphological change and apoptotic cell death such as formation of apoptotic bodies, DNA fragmentation and increased populations of apoptotic-sub G1 phase. And we observed the effects of ECT on loss of mitochondrial membrane potential (MMP), using the JC-1 probe by DNA flow cytometric analysis. Apoptosis of HepG2 cells by ECT was associated with a down-regulation of anti apoptotic Bcl-2 expression, inhibitor of apoptosis proteins (IAPs) expression and proteolytic activation of caspase-3 and caspase-9. However, ECT did not affect the pro-apoptotic Bax expression and activity of caspase-8. ECT treatment also concomitant degradation and /or inhibition of poly (ADP-ribose) polymerase (PARP), phospholipase C-1 ($PLC{\gamma}1$). Furthermore, ECT treatment caused a dose-dependent inhibition of iNOS and cyclooxygenase-2 (Cox-2). Additionally ECT have been implicated in the regulation of telomerase expression. ECT treatment induced the down-regulation of telomerase reverse transcriptase mRNA (hTERT) expression of HepG2 cells. Taken together, these findings suggest that ECT may be a potential chemotherapeutic agent for the control of HepG2 human hepatoma cells.

• 한국미생물·생명공학회지
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• 제31권4호
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• pp.413-420
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• 2003

축산폐기물의 퇴비화에 사용된 혼합 미생물을 이용해서 음식쓰레기 처리 과정에서 발생되는 악취를 효과적으로 처리 하고자 하였다. 시판되는 가정용 음식쓰레기 처리기를 사용하여 음식쓰레기의 퇴비화와 악취저강 특성을 조사하였다. 퇴비화는 10일 경과후부터 인정화되었으며, 혼합 미생물을 첨가한 경우 온도와 pH가 혼합 미생물을 첨가하지 않은 것과 비교해 더 빨리 증가하였으며, 퇴비화의 지표 중에 하나인 전기전도도 (Conductivity)도 1.2 에서 2.4 mS/cm로 혼합 미생물을 첨가하지 않은 경우의 1.3 mS/cm 보다 급격한 상승을 보였다. 식품쓰레기 처리 중에 발생되는 악취 물질, 즉 황화수소와 저급지방산은 8 일 동안에 각각90-100％와 70-80％로 효과적으로 제거되었다. 또한 알칼리 상태와 고온의 조건에서 성장하는 미생물이 퇴비화 과정 중에 우점 하였으며, Bacillus cereus No. 15 균주가 혼합 미생물 중 효과적인 식품쓰레기처리와 악취제거에 관여하고 있다는 사실을 증명하였다.