Mg₂SiO₄ : La, Ho 열형광선량계에서 활성제 농도가 글로우 커브에 미치는 영향 La, Ho TLD on Activation Concentration

김영국,손인호,채건식,노경석,오재근,이은숙 경남대학교 신소재연구소 1996 論文集 Vol.6 No.-

본 연구에서는 Mg₂SiO₄에 활성화 물질로 La, Ho를 첨가하여 열형광체를 제작하였고 불순물의 농도를 1wt.% ∼5 wt.%까지 변화시키면서 열평광강도의 glow curve를 측정하였다. 도한 열형광체의 glow curve를 peak shape법으로 분석해서 TL특성에 대한 포획 매개변수와 활성화 에너지, 발광차수, 선량의존성등을 조사하였으며, 그 물리적 특성을 조사하고 선량계로서 타당성과 실용성을 확인하였다. The Mg₂SiO₄: La, Ho thermoluminescent phospher has been prepared by sintring Mg₂SiO₄after doping the transition elements La and Ho. The heating rate is 10℃/sec at this thermoluminescent phospher are heated. The maximum peaks are found in the measured Mg₂SiO₄: La and Ho. TL glow curve at 229℃ and 345 C when the 1 wt.%-5 wt.%. The glow curve of TLD increased TL intensity and temperature of peak appears to the high temperature when the heating rate is l0℃/sec-25℃/sec. The activation energy of the main peak has been estimated by the peak shape method. The estimated activation energies are 1.77 eV. 1.52 eV respectively. The thermoluminescence process in Mg₂SiO₄: La and Ho are found to the 2nd order when the main peak of the glow curve is analyzed by peak shape method. The dose responses of Mg₂SiO₄: La and Ho TLD are linear up to intensity of X-ray.

Anti-Inflammatory and Cytoprotective Effects of TMC-256C1 from Marine-Derived Fungus <i>Aspergillus</i> sp. SF-6354 via up-Regulation of Heme Oxygenase-1 in Murine Hippocampal and Microglial Cell Lines

Kim, Dong-Cheol,Cho, Kwang-Ho,Ko, Wonmin,Yoon, Chi-Su,Sohn, Jae Hak,Yim, Joung Han,Kim, Youn-Chul,Oh, Hyuncheol MDPI AG 2016 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.17 No.4

<P>In the course of searching for bioactive secondary metabolites from marine fungi, TMC-256C1 was isolated from an ethyl acetate extract of the marine-derived fungus <I>Aspergillus</I> sp. SF6354. TMC-256C1 displayed anti-neuroinflammatory effect in BV2 microglial cells induced by lipopolysaccharides (LPS) as well as neuroprotective effect against glutamate-stimulated neurotoxicity in mouse hippocampal HT22 cells. TMC-256C1 was shown to develop a cellular resistance to oxidative damage caused by glutamate-induced cytotoxicity and reactive oxygen species (ROS) generation in HT22 cells, and suppress the inflammation process in LPS-stimulated BV2 cells. Furthermore, the neuroprotective and anti-neuroinflammatory activities of TMC-256C1 were associated with upregulated expression of heme oxygenase (HO)-1 and nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) in HT22 and BV2 cells. We also found that TMC-256C1 activated p38 mitogen-activated protein kinases (MAPK) and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways in HT22 and BV2 cells. These results demonstrated that TMC-256C1 activates HO-1 protein expression, probably by increasing nuclear Nrf2 levels via the activation of the p38 MAPK and PI3K/Akt pathways.</P>

ERK1/2 activation in quercetin-treated BEAS-2B cell plays a role in Nrf2-driven HO-1 expression

이윤진,Jun-Hwan Song,Myung-Ho Oh,Yong-Jin Lee,김용배,Jae-Hyuk Im,이상한 대한독성 유전단백체 학회 2011 Molecular & cellular toxicology Vol.7 No.4

Quercetin, a member of the flavonoids,has been heralded as chemopreventive agent, generally because of its free radical-scavenging and antiproliferative activities. In this process, NF-E2-related factor-2 (Nrf2) plays a role in protecting cells from oxidative damage; however, the exact mechanisms in which bronchial epithelial cells respond to quercetin by activating Nrf2 are not fully understood. Here, we report the role of extracellular signal-regulated kinase (ERK) activation in response to quercetin. Quercetin treatment decreased the viability of human bronchial epithelial BEAS-2B cells in a dose- and time-dependent manner. ERK1/2 was activated within 10 min of quercetin addition and then remained increased above control level throughout 48 h, whereas AKT phosphorylation was suppressed from the first 1 h of quercetin treatment. Inhibition of Erk1/2 phosphorylation attenuated quercetin-induced loss of cell viability. Nrf2levels in both nuclear and whole cell lysates increased after quercetin treatment and was accompanied by the increase of heme oxygenase-1 (HO-1) protein level,indicating that increased HO-1 expression is Nrf2-mediated. Activation of the Nrf2/HO-1 system after quercetin treatment was suppressed by the pretreatment with MEK inhibitor, PD98059. Also, silencing Nrf2 with siRNA decreased cell viability and augmented cytotoxic effect of anticancer drug LBH589. Overall, our results indicate that quercetin induces the up-regulation of Nrf2-mediated HO-1 expression, at least in part, via MEK/ERK1/2 signaling, as an adaptive mechanism which may provide advantages for cell proliferation and enhance survival despite endogenous and/or exogenous oxidative insults.

급성전골수성백혈병에서 백혈구성분채집술에 이은 치명적인 뇌출혈 2예

오윤정,박소윤,김윤정,한동석,김현수,최진혁,남동기,임호영,김효철,주희재 아주대학교 의과학연구소 1998 아주의학 Vol.3 No.1

The aim of this study is to report 2 cases of acute promyelocytic leukemia who died from intracranial hemorrhage following leukapheresis and to provide proper preventive measures against hemorrhage following leukapheresis. From 1994 to 1997, a total of twenty-six patients with leukemia underwent leukapheresis to control hyperleukocytosis at Ajou University Hospital. Two patients with acute promyelocytic leukemia received all-trans retinoic acid but developed drug-induced hyperleukocytosis. Shortly after leukapheresis, they died from intracranial hemorrhage. The risk factors for fatal hemorrhage are thought to be coexisting disseminated intravascular coagulation(DIC), thrombocytopenia aggravated by leukapheresis, exacerbated coagulopathy related to mechanical trauma through leukapheresis and the excess use of citrate during leukapheresis. To reduce the risk of the bleeding associated with leukapheresis, it is necessary to replace platelet sufficiently before and after leukapheresis and to give calcium to correct coagulopathy induced by excess citrate which is used as anticoagulant as well as the correction of disseminated intravascular coagulation.

In Vitro 고삼투압이 정자 원형질막의 Protein Tyrosine Phosphorylation에 미치는 영향

오영근,장재호,최인호,정노팔,신형철,곽병주 대한의생명과학회 2000 Journal of biomedical laboratory sciences Vol.6 No.4

정자의 원형질막은 삼투압에 의해서 영향을 받는다고 보고되고 있다. 이중 세포막내 분자구조의 변화 특히 막지질 구조의 변화와 동반되는 이온채널의 변화 그리고 Ca2+과 HCO-3의 유동성과도 밀접한 관련이 있는 것으로 보고되고 있다. 지금까지의 연구보고에 의하면, 정자의 첨체반응 (acrosome reaction)이 일어날 경우 protein tyrosine phosphorylation이 증가되는데 이것은 cAMP, protein kinase A 등을 통하여 작용되는 것으로 보고되고 있다. 막의 지질변화를 유도하는 물질로 일종의 sterol acceptor인 BSA가 알려져 있는 바, 실제로 BSA가 막지질 성분에 미치는 영향을 관찰한 결과 cholesterol이 유출되고 이온 등의 유동성 변화가 일어나, 이 유동성 변화가 정자의 adenylyl cyclase를 활성화시켜 cAMP를 증가시키고, PKA가 활성화되어 결과적으로 Protein tyosine phosphorycation이 유도된다고 보는 것이다. 침체반응과 protein tyrosine phosphorylation과는 밀접한 관계가 있는 것으로 사료되고 있다. 본 연구는 정자 원형질막에서 cholesterol이 유출되어 protein tyrosine phosphorylation이 유도될 때, BSA와 같은 sterol acceptor가 작용할 것이라는 전제하에, 고삼투압 하에서 탈수로 인해 원형질막이 위축되더라도 sterol acceptor가 존재한다면 막지질 성분의 구조적 변화가 억제 될 수 있을 것이라는 가설을 설정하였다. 실험결과, 저온 및 고삼투압 하에서 정자운동은 감소되지만 원형질막의 구조적 변화는 없고, 삼투압에 대한 반응정도는 원형질막을 통한 수분이동과 세포용적 변화에 따라 비례적으로 일어난다고 하는 사실을 발견하였다. 이 결과는 정자보존에 있어서 저온변화에 영향을 미치는 여러 인자들 특히 protein fgrosine phosphorylation의 증가와 밀접한 관계가 있음을 시시해 준다. 또한 sterol acceptor로 알려진 BSA는 삼투압이 변화되더라도 역시 중요한 인자로 작용할 수 있음을 알 수 있었으며, 특히 고삼투압으로의 변화는 cAMP와 protein kiname A를 거치는 신호전달과정에 있어서 중요한 요인이라는 사실을 확인할 수 있었다. It has been reported that plasma membrane activity of the spermatozoa may be susceptible to be influenced by extracellular osmolality and such membranous changes involve intracellular molecular changes, special regard to the structure of membranous lipids, and the accompanying ion-channel of which are closely related with their fluidity of Ca2+ and HCO-3. It is of common recognition that a certain kind of sterol acceptor player an important to induce lipid fluctuation of the sperm plasma membrane which have been influenced by BSA administration and came in effect to outflow of cholesterol from the spermatozoa and resulted in changes of ionic fluidity to facilitate adenylyl cyclase, and to induce protein tyrosine phosphorylation by increase of cAMP and activation of PKA. Thus it seems likely that an augmentation of the acrosomal reaction is closely related with protein tyrosine phosphorylation. The following experimental results were obtained in the present study; Under the high osmolality conditions, the spermatozoa motility declined significantly and the structural change of the plasma membrane diminished to confirm that the response degrees to the osmolality depended upon the water transfer volume through the plasma membrane and the changes of cellular volume. Those experimental results suggest that a physiological parameter such as low temperature condition played an important role for presentation of spermatozoa and that inducement of spermatozoa activation for reinforcement of protein tyrosine phosphorylation. On the other hand, it seemed likely that the BSA administration as one of sterol acceptors might represent a key role also under the high osmolality condition and their result also suggests that osmolality change, special regard to high osmolality condition may play an important role also in the processes of signal transmission

광촉매 산화반응에서 촉매의 비표면적과 기공 크기가 활성에 미치는 영향

오송택,최재석,이한수,이호인 한국공업화학회 2003 응용화학 Vol.7 No.2

Mesoporous TiO₂was prepared using esterification between poly ethylene glycol(PEG) and acetic acid, and was applied to the photocatalystic decomposition of 2-isopropyl-6-methyl-4-pyrimidinol (IMP), cyanide ion, and rhodamine B (RB) in order to study the effect of surface area and pore size on the activity. When catalysts had similar specific surface areas, the activity of photocatalytic decomposition of IMP was proportional to the pore size due to more facile diffusion into the pore. However, in case of cyanide which size is much smaller than the pore size of TiO₂the activity was proportional to the specific surface area, while a very large size molecule of RB caused low activity due to difficulty in diffusion into the pore.

Cu량에 따른 Bi₂Sr₂Ca₂Cu₃O_(x)화합물의 특성에 관한 연구

오재근,주유환,손인호 경남대학교 환경문제연구소 2003 환경연구 Vol.26 No.-

We have grown Bi₂Sr₂Ca₂Cu₃O_(x) compound by improved directional solidification method with changing a quantity of Cu from 3.0 to 4.0 in order to examine substitution effect. The highest critical temperature arising in the Cu3.4 sample is about 110K. The critical temperatures of Cu3.2 sample and Cu3.8 sample are found to be about 80K. The Cu3.0 and Cu4.0 samples do not show the superconductivity. From the experiment we understand that the Cu3.4 sample is Bi-2223 phase and the other sample is a mixture of the Bi-2212 and some other phases.

SAW를 이용한 ZnSe의 TAV 연구

오재근,손인호,채건식,김영국 경남대학교 환경문제연구소 1993 환경연구 Vol.15 No.-

The energy gap in ZnSe sing1e crystal epilayer have been studied by measuring Transverse Acoustoelectric Voltage(TAV). The energy gap of ZnSe was 2.6eV at room temperature. Trap levels were calculated by Heating rate, Peak shape and Initial rise methods respectively. Also we can calculated cross section of ZnSe.

성격평가 질문지의 조증척도 요인구조 : 정신과 환자집단 자료를 중심으로

오자영,노승호,김재현,오상우 圓光大學校 醫科學硏究所 2005 圓光醫科學 Vol.20 No.2

人工海水에 의한 複合組織鋼의 表面腐蝕이 疲勞破壞强度에 미치는 影響

吳世旭,姜鎬珉,李悅宰 東亞大學校 大學院 1986 大學院論文集 Vol.11 No.-

The influence of seawater corrosion on fatigue life at low stress level appears to be larger than that at high stress level about M.E.F. dual phase steel. Especially, the variation-range between high stress level and low stress level is large in the sea bottom corrosion of 250 hours and 1000 hours about S-N curves. According to corrosion time and corrosion conditon the amount of reduction of fatigue limit and fatigue life is varied. Fatigue limit and fatigue life for sea surface corrosion condition is lower than those for sea bottom corrosion condition and the influence of sea surface corrosion of fatigue life is large. It is appeared the relation between fatigue length and the number of cycle is depended on stress level, corrosion time and corrosion condition and corrosion pits occurred by seawater corrosion are become the cause of micro-crack. The variation-range of the crack propagation rate for low stress level is larger than that for high stress level. Portions of these fracture surface don't occur plastic deformation by S.E.M observation. However, these are found quasi-cleavage fracture that occur seperate fracture.