• Bulletin of the Korean Chemical Society
• /
• 제31권1호
• /
• pp.112-115
• /
• 2010

Transparent conducting undoped and Al impurity doped ZnO films were deposited on glass substrate by spin coat technique using 24 days aged ZnO precursor solution with solution of ethanol and diethanolamine. The films were characterized by UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), electrical resistivity ($\rho$), carrier concentration (n), and hall mobility ($\mu$) measurements. XRD data show that the deposited film shows polycrystalline nature with hexagonal wurtzite structure with preferential orientation along (002) crystal plane. The SEM images show that surface morphology, porosity and grain sizes are affected by doping concentration. The Al doped samples show high transmittance and better resistivity. With increasing Al concentration only mild change in optical band gap is observed. Optical properties are not affected by aging of parent solution. A lowest resistivity ($8.5 \times 10^{-2}$ ohm cm) is observed at 2 atomic percent (at.%) Al. With further increase in Al concentration, the resistivity started to increase significantly. The decrease resistivity with increasing Al concentration can be attributed to increase in both carrier concentration and hall mobility.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2001년도 The 8th International Symposium
• /
• pp.20-33
• /
• 2001

A major portion of drugs used in Ayurvedic system of medicine which has been practiced since the early human civilization in Indian subcontinent were of plant origin. It should be noted that 70% of the population in this region depends on Ayurveda for their medical treatment and 60% of the drug resources are obtained from the Himalayan region. Therefore, Nepal becomes a potential source of plant drug resource since it occupies a major portion of the Himalaya. In the present paper, in general a current status of medicinal plant resources of Himalayan region especially Nepal will be discussed. In addition to this, a typical example of antidiabetic activity of Shilajit will be taken for the discussion. Shilajit is one of the crucial elements in several formulations including those of Rasayana, a therapy in Ayurveda, which has been practiced in the prevention of ageing and mental disorder. Although, Shilaiit is widely used for the treatment of diabetes, no satisfactory scientific reports are available up to now. The crude Shilajit in the market is a dark brown or black rock-like substance collected from the Himalayan region with a strong smell of cow's stale urine. In our studies, Shilajit (collected in the central Himalayan region) prevented the diabetes in nonobese diabetic (NOD) mice model. Shilajit also prevented the diabetes in the rats against the action of multiple low-dose (10 ㎎/㎏, i.v., 5 times) of streptozotocin. On the other hand, Shilajit did not show antioxidative activity. The preventive action of Shilajit on diabetes is mainly focused on the Th1 and Th2 cell activities, since Th2 cells activity was found to be significantly upregulated. Shilajit, however, showed a mild action in controlling the blood sugar level in young, old, and mild diabetic rats, but not in the severe diabetic rats. It also stimulated the nitric oxide production in macrophages. Based on these evidences, the antidiabetic activities of Shilajit appear to be immunomodulative probably by protecting or strengthening insulin-producing b-cells In the pancreas. further systematic research on constituents of Shilajit and its quality evaluation is necessary to enable the use of natural medicines in the treatment of diabetes.

• Journal of Acupuncture Research
• /
• 제23권2호
• /
• pp.33-46
• /
• 2006

Alzheimer's disease (AD) is the most prevalent form of neurodegenerative disease associated with aging in the human population. This disease is characterized by the extracellular deposition of beta-amyloid peptide $(A{\beta})$ in cerebral plaques. $A{\beta}$ is derived from the ${\beta}-amyloid$ precursor protein (APP) by the enzymes, ${\beta}-$ and ${\eta}o-secretase$. Compounds that ${\beta}-$ or ${\eta}o-secretase$ inhibit activity, can reduce the production of $A{\beta}$ peptides, and thus have therapeutic potential in the treatment of AD. Increasing body of evidence has been demonstrated that Bee Venom(BV) Acupuncture could compete with complex protein involving in multiple step of $NF-{\kappa}B$ activation and exert the anti-inflammatory potential of combined inhibition of the prostanoid and nitric oxide synthesis systems by inhibition of IKK and $NF-{\kappa}B$. In this study, I investigated possible effects of BV on memory dysfunction caused by lipopolysaccharide (LPS) and $A{\beta}$ through inhibition of secretases activities and $A{\beta}$ aggregation. I examined the improving effect of BV on the LPS (2.5 mg/Kg, i.p.)-induced memory dysfunction using passive avoidance response and water maze tests in the mice. BV (0.84, $1.67\;{\mu}g/ml$) reversed the LPS-induced memorial dysfunction in dose dependent manner. BV also dose-dependently attenuated LPS-induced ${\beta}$ and ${\eta}o-secretase$ activities in cerebral cortex and hippocampus of the mice brain. This study therefore suggests that BV acupuncture method may be useful for prevention of development or progression of AD.

• International Journal of Oral Biology
• /
• 제36권3호
• /
• pp.155-162
• /
• 2011

Eugenol (4-allyl-2-methoxyphenol) is a naturally occurring phenolic compound that is widely used in dentistry as a component of zinc oxide eugenol cement that is commonly applied to the mouth environment. Cisplatin is one of the most potent known anticancer agents and shows significant clinical activity against a variety of solid tumors. This study was undertaken to investigate the synergistic apoptotic effects of co-treatments with eugenol and cisplatin on human melanoma (G361) cells. To investigate whether this co-treatment efficiently reduces the viability of G361 cells compared with each single treatment, an MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis of DNA hypoploidy. Western blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) changes were also assayed. The results indicated that a co-treatment with eugenol and cisplatin induced multiple pathways and processes associated with an apoptotic response in G361 cells including nuclear condensation, DNA fragmentation, a reduction in MMP and proteasome activity, the increase and decrease of Bax and Bcl-2, a decreased DNA content, the release of cytochrome c into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, and the activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD). In contrast, separate treatments of 300 ${\mu}M$ eugenol or 3 ${\mu}M$ cisplatin for 24 h did not induce apoptosis. Our present data thus suggest that a combination therapy of eugenol and cisplatin is a potential treatment strategy for human melanoma.

• The Korean Journal of Physiology
• /
• 제29권1호
• /
• pp.61-67
• /
• 1995

The extract of Ginkgo bibloba (EGb) is a complex mixture of natural products from the Ginkgo leaves and clinically used for the treatment of cerebral and peripheral circulatory disturbances due to its combined activity of several vasoactive principles. In this study we investigated the action of EGb and its mechanism in isolated rabbit corporal smooth muscle to evaluate the possibility of using this material as a pharmacoerecting agent. Strips of rabbit corpus cavernosum were mounted in organ chambers to measure isometric tension. EGb began to exert an relaxing effect at 1 mg/ml in the submaximally precontracted muscle strips with phenylephrine $(PHE,\;5{\times}10^{-6}\;M)$; causing concentration-dependent relaxation with maximal effect at $3{\sim}5\;mg/ml$. That relaxation was partially inhibited by removal of the smooth muscle endothelium or by pretreatment with a NO scavenger, pyrogallol $(10^{-4}\;M)$ or the guanylate cyclase inhibitor, methylene blue $(10^{-4}\;M)$. Pretreatment with EGb (3 mg/ml) inhibited PHE- $(5{\times}10^{-6}\;M)$ or KCI- (20 and 40 mM) induced contraction of muscle strip. In calcium-free high potassium solution EGb depressed the basal tone of the depolarized muscle strip and inhibited calcium-induced contraction when $CaCl_2$ $(10^{-4}\;M)$ was added. These results suggest that EGb relaxes rabbit corpus cavernosal smooth muscle through multiple action mechanisms that include increasing the release of nitric oxide from the corporal sinusoidal endothelium, sequestration of intracytosolic calcium, and maybe a hyperpolarizing action.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2018년도 추계학술논문요약집
• /
• pp.103-103
• /
• 2018

The liquid cathode processing is necessary to separate cadmium from the actinide elements in the pyroprocessing since the actinide deposits are dissolved or precipitated in a liquid cathode. Distillation process was employed for the cathode processing owing to the compactness. It is very important to avoid a splattering of cadmium during evaporation due to the high vapor pressure. Several methods have been proposed to lower the splattering of cadmium during distillation. A multi-layer porous round cover was proposed to avoid a cadmium splattering in our previous study. In this study, distillation behavior of $Cd-ZrO_2$ and Cd - Bi systems were investigated to examine a multi-layer porous round cover for the development of the cadmium splatter shield of distillation crucible. It was designed that the cadmium vapor can be released through the holes of the shield, whereas liquid drops can be collected in the multiple hemisphere. The cover was made with three stainless steel round plates with a diameter of 33.50 mm. The distance between the hemispheres and the diameter of the holes are 10 and 1 mm, respectively. Bismuth or zirconium oxide powder was used as a surrogate for the actinide elements. About 40 grams of Cd was distilled at a reduced pressure for two hours at various temperatures. The mixture of the cadmium and the surrogate was distilled at 470, 570 and $620^{\circ}C$ in the crucible with the cover. Most of the bismuth or zirconia remained in the crucible after distillation at 470 and $570^{\circ}C$ for two hours. It was considered that the crucible cover hindered the splattering of the liquid cadmium from the distillation crucible. A considerable amount of the surrogate material reduced after distillation at $620^{\circ}C$ due to the splattering of the liquid cadmium. The low temperature is favorable to avoid a liquid cadmium splattering during distillation. However, the optimum temperature for the cadmium distillation should be decided further, since the evaporation rate decreases with a decreasing temperature.

• 한국산학기술학회논문지
• /
• 제20권3호
• /
• pp.483-490
• /
• 2019

화재 발생으로 인한 피해 및 영향에 관해 국내에서의 연구는 미비한 상태이다. 따라서 화재 발생에 따른 연기 농도를 측정하기 위한 기기를 개발함으로 연기가 주변 지역으로 확산될 경우의 농도를 측정하고자 한다. 본 논문에서 제안한 공기질 측정 시스템은 기존의 측정기와는 달리 CO, CO2, NOx VOCs, NH3 등 총 5가지의 가스를 동시에 측정할 수 있고, 센서보호 알고리즘을 통해 높은 내구 수명을 갖는다. 또한, 모니터링 프로그램을 통해 실시간 가스 변화량을 측정하는 시스템을 구성하였다. 상용 가스 분석기와의 비교를 통해 가스농도 측정의 신뢰성을 확보하였으며, 실내 및 실외 화재실험을 통해 발화점 주변에 존재하는 가스농도 평가를 실시하여 신뢰성이 높은 데이터를 얻을 수 있음을 확인하였다.

• Journal of Nutrition and Health
• /
• 제52권4호
• /
• pp.408-411
• /
• 2019

Purpose: This study investigated the effect of bioactive Yeonsan Ogye peptides (YOPs) intake on changes in the hepatic anti-oxidant indexes in male rats. Methods: Sprague-Dawley male rats were divided into 3 groups and given a casein-based AIN-93G diet and distilled water ad libitum without any added YOPs (control), distilled water with 250 mg of YOPs (Y250), or 500 mg of YOPs (Y500) per kg of body weight for 4 weeks. YOP dose was decided as referred to in the referenced study where toxicity did not occur. The hepatic anti-oxidant indexes were determined using a commercial kit. Statistical analysis was performed using SPSS version 23.0 and are expressed as $mean{\pm}standard$ error of mean. Differences among the groups were evaluated by one-way analysis of variance followed by post hoc Duncan's multiple comparisons test. Results: There were no differences in the body weights, weight gain, food intake, food efficiency ratio, or organ weight, including liver, kidney, spleen, thymus, and epididymal fat, among all of the groups. The hepatic nitric oxide (NO) level in the Y500 group was lower than that in the control and Y250 groups, and the hepatic malondialdehyde (MDA) level was lower in the Y500 group than in the Y250 group. The differences in hepatic superoxide dismutase (SOD) and catalase (CAT) activities were not statistically significant between the groups. From these results we speculated that YOPs may have anti-oxidative abilities to regulate NO and MDA production without affecting SOD and CAT activities. Conclusion: YOPs are presumed to act as anti-oxidants in the animal or human body.

• Journal of Ginseng Research
• /
• 제43권4호
• /
• pp.539-549
• /
• 2019

Background: 20(S)-Protopanaxadiol (PPD), the aglycone part of 20(S)-protopanaxadiol ginsenosides, possesses antidepressant activity among many other pharmacological activities. It is currently undergoing clinical trial in China as an antidepressant. Methods: In this study, an ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass tandem mass spectrometry method was established to identify the metabolites of PPD in human plasma and urine following oral administration in phase IIa clinical trial. Results: A total of 40 metabolites in human plasma and urine were identified using this method. Four metabolites identified were isolated from rat feces, and two of them were analyzed by NMR to elucidate the exact structures. The structures of isolated compounds were confirmed as (20S,24S)-epoxydammarane-12,23,25-triol-3-one and (20S,24S)-epoxydammarane-3,12,23,25-tetrol. Both compounds were found as metabolites in human for the first time. Upon comparing our findings with the findings of the in vitro study of PPD metabolism in human liver microsomes and human hepatocytes, metabolites with m/z 475.3783 and phase II metabolites were not found in our study whereas metabolites with m/z 505.3530, 523.3641, and 525.3788 were exclusively detected in our experiments. Conclusion: The metabolites identified using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry in our study were mostly hydroxylated metabolites. This indicated that PPD was metabolized in human body mainly through phase I hepatic metabolism. The main metabolites are in 20,24-oxide form with multiple hydroxylation sites. Finally, the metabolic pathways of PPD in vivo (human) were proposed based on structural analysis.

• 대한금속재료학회지
• /
• 제49권2호
• /
• pp.112-120
• /
• 2011

The out-of-phase thermo-mechanical fatigue (OP TMF) in a <001> oriented single crystal nickel-based superalloy CMSX-4 has been studied. OP TMF life was less than a half of low cycle fatigue(LCF) life in spite of a small hysteresis loop area of OP TMF compared to that of LCF. The failure was caused by the initiation of a crack at the oxide-layered surface followed by its planar growth along the <100> ${\gamma}$ channel in both LCF and OP TMF. However, deformation twins appeared near the major crack of OP TMF. The multiple groups of parallel twin plates on {111} planes provided a preferential path for crack propagation, which caused a significant decrease in OP TMF life. Additionally, the analysis on the surface crack morphology revealed that the tensile strain at the minimum temperature of OP TMF was found to accelerate the crack propagation.