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        검색결과 374

        141.
        2013.03 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to examine the effect of antioxidant treatment during parthenogenetic activation procedure on the reactive oxygen species (ROS) levels and in vitro development of porcine parthenogenetic embryos. Porcine in vitro matured oocytes were activated by a combination of electric stimulus and 2 mM 6- dimethylaminopurine (6-DAMP) before in vitro culture. During the activation period, oocytes were treated with 50 μM β-mercaptoethanol (β-ME), 100 μM L-ascorbic acid (Vit. C) or 100 μM L-glutathione (GSH). To examine the ROS level, porcine parthenogenetic embryos were stained in 10 μM dichlorohydrofluorescein diacetate (H2DCFDA) dye 20 h after culture, examined under a fluorescence microscope, and the fluorescence intensity (pixels) were analyzed in each embryo. The parthenogenetic embryos were cultured for 6 days to evaluate the in vitro development. The apoptosis was measured by TUNEL assay. The H2O2 levels of parthenogenetic embryos were significantly lower in antioxidant treatment groups (26.9±1.6~29.1±1.3 pixels/embryo, p<0.05) compared to control (33.2±1.7 pixels/embryo). The development rate to the blastocyst stage was increased in antioxidant treatment groups (32.0~32.5%) compared to control (26.9%, p<0.05), although, there was no difference in apoptosis among groups. The result suggests that antioxidant treatment during parthenogenetic activation procedure can inhibit the ROS generation and enhance the in vitro development of porcine parthenogenetic embryos.
        4,000원
        142.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한반도에서 산출되는 초염기성 맨틀포획암의 지화학적 특징과 평형 온도와 압력 조건을 계산하고, 산소동위원소비를 분석하였다. 연구 결과 (1) 한반도 맨틀포획암은 전형적인 초염기성 포획암(MgO: 49.12-50.95 wt.%, Mg값: 90.1-92.2)으로 구성되어 있다. (2) 한반도 맨틀포획암의 평형온도는 854-1016˚C이고, 압력은 4.6-24.4 kbar로 얻어졌다. (3) 맨틀포획암을 구성하는 감람석의 산소동위원소비(δ18Ool)는 5.06-5.51‰의 균질한 값으로 N-MORB와 상부 맨틀 감람석의 값(δ18O: 5.2±0.2‰)과 유사하다. 그러나 백두산과 제주도의 맨틀포획암을 구성하는 감람석의 산소동위원비는 각각 5.07-5.51‰과 5.07-5.45‰로 상대적으로 넓은 범위의 δ18O 값을 갖고 있다. 이 결과를 바탕으로, 이 연구에서는 백두산 맨틀포획암의 높은 δ18O가 맨틀포획암 물질에 재순환된 퇴적물원 EM2 물질의 혼입 때문일 수 있다는 가능성을 제안하였다.
        4,500원
        143.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To evaluate the biological response of sea squirt Halocynthia roretzi with different body size to heavy metals and its suitability for ecotoxicity assays, the effects of Cr, Cu and Zn on its clearance and oxygen consumption rates were investigated. Clearance and oxygen consumption rates of H. roretzi with various body sizes were calculated at different metal concentrations. Both clearance and oxygen consumption rate were negatively correlated with body sizes. Clearance rate of H. roretzi decreased gradually with increasing concentration of heavy metal, the decreasing rate was in an order of Cr¤Cu¤Zn. The oxygen consumption rate first increased at low metal concentration (below 100 μg L-1) and then decreased rapidly with increasing metal concentrations. The decreasing rate was in an order of Cu¤Cr=Zn. There was a trend that the clearance rate and oxygen consumption rate decreased drastically under a concentration of 400 μg L-1, and then decreased smoothly when the metal ion concentration increased continually. So the oxygen consumption and clearance rate at a concentration of 400 μg L-1 Cu could be thought as a suitable biological tool for exotoxicology analysis.
        4,000원
        144.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to investigate the effects of 70% EtOH extract obtained from Hovenia dulcis Thunberg on enzymes relating reactive oxygen intermediate, cancer-stricken animals induced by DEN (N, N diethylnitrosamine) were recovered by administering the extract of Hovenia dulcis Thunberg. It showed that there was no effect on the generation of superoxide radical by the extract of Hovenia dulcis Thunberg. However, considering the increase of the activity of Cu, Zn-SOD and Mn-SOD in the tested animal class, the extract of Hovenia dulcis Thunberg could participate directly in removing of superoxides. The experimented-animals treated with the extract of Hovenia dulcis Thunberg showed an increase in the activity of the enzymes, catalase and glutathione peroxidase, which can eliminate hydrogen peroxide pertained in liver tissue. The extract of Hovenia dulcis Thunberg seemed to have some factors that accelerate the oxidation. Also, the extract of Hovenia dulcis Thunberg showed effects on the enzymes relating to the active oxygen toxicity which could be an indicator of aging and body toxicity.
        4,000원
        145.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research was planned and executed to evaluate how the composition of Yack-sun (oriental diet therapy) tea can effect the health conditions of people who are suffering from diet-related diseases such as being overweight, obese and hyperlipidemic, by taking Yack-sun tea in a form of nutritional supplement with daily meals. We produced Kangjieum with Lycense Mill., Polygonum multflorum Thunb, Cassia tora L., Crataegus pinnatifida Bge and Salvia miltiorrhiza Bge. We evaluated the effects of this tea on serum lipids, on homocysteine concentration, and on active oxygen contents, oxidative stress by clinical practices. We have determined that this tea has a significant effect on decreasing body fat content, decreasing total cholesterol, decreasing LDL-cholesterol, and decreses triglyceride and homocysteine concentrations. In addition, blood active oxygen content and oxidative stress were significantly decreased. We think that scientific and objective evaluation was performed on the components of Kangjieum prescription. We concluded that we could apply the components, not only in a form of tea, but also in other forms of various foods. The information we received from this conclusion will be basic information on how we can apply oriental medicinal resources into other food and will be a steppingstone for medicinal herbs to place a foot in the field of functional food research, which already draws sizable attention world-wide.
        4,000원
        146.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, it was observed through the ability of performing secondary tasks and baseline fetal heart rate how the supply of lavender, peppermint and highly concentrated oxygen (40%) affected distraction due to the performance of secondary tasks in the driving environment. Twelve male university students conducted secondary tasks while driving in the environments (6 in total) mixed and designed with oxygen concentration (21%, 40%) and the condition of odors (Normal, Lavender, Peppermint). The test was proceeded in order of stable state (5mins), driving (5mins), and secondary tasks (1min), and by extracting ECG data from every section by 30secs, the mean value of baseline fetal heart rate was calculated. As a result of analysis, in the ability of performing secondary tasks, a percentage of correct answers showed no difference in oxygen concentration and the condition of odors (p > 0.05). In performance completion time, a percentage of correct answers decreased showing a statistically significant difference in the condition of odors compared with the condition where odors were not provided (p < 0.05). As for baseline fetal heart rate, in the comparison between sections, while performing secondary tasks, it increased showing a significant difference compared with stable state and driving state (p < 0.05). The effect of interaction was observed in oxygen concentration and the condition of odors. When odors were not provided, baseline fetal heart rate decreased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05), however, when peppermint was provided, it increased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05). In conclusion, the fact that the condition of odors increased the ability of calculation, and when only the highly concentrated oxygen was provided, parasympathetic nerve system was activated, however, when highly concentrated oxygen was provided with peppermint at the same time, sympathetic nervous system (sns) was activated, which had a negative effect on the autonomic nervous system was drawn.
        4,000원
        147.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, an oxygen plasma treatment was used as a low temperature debinding method to form a conductive copper feature on a flexible substrate using a direct printing process. To demonstrate this concept, conductive copper patterns were formed on polyimide films using a copper nanoparticle-based paste with polymeric binders and dispersing agents and a screen printing method. Thermal and oxygen plasma treatments were utilized to remove the polymeric vehicle before a sintering of copper nanoparticles. The effect of the debinding methods on the phase, microstructure and electrical conductivity of the screen-printed patterns was systematically investigated by FE-SEM, TGA, XRD and four-point probe analysis. The patterns formed using oxygen plasma debinding showed the well-developed microstructure and the superior electrical conductivity compared with those of using thermal debinding.
        4,000원
        149.
        2012.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Significant improvements in the switching voltage distribution are required for the development of unipolar resistivememory devices using MnOx thin films. The Vset of the as-grown MnOx film ranged from 1 to 6.2 V, whereas the Vset of theoxygen-annealed film ranged from 2.3 to 3 V. An excess of oxygen in an MnOx film leads to an increase in Mn4+ contentat the MnOx film surface with a subsequent change in the Mn4+/Mn3+ ratio at the surface. This was attributed to the changein Mn4+/Mn3+ ratios at the MnOx surface and to grain growth. Oxygen annealing is a possible solution for improving theswitching voltage distribution of MnOx thin films. In addition, crystalline MnOx can help stabilize the Vset and Vreset distributionin memory switching in a Ti/MnOx/Pt structure. The improved uniformity was attributed not only to the change of thecrystallinity but also to the redox reaction at the interface between Ti and MnOx.
        4,000원
        150.
        2012.06 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine the optimal concentration and treatment time of antioxidants for inhibition of the ROS generation in bovine somatic cell nuclear transfer (SCNT) embryos. Bovine oocytes were activated parthenogenetically, during which oocytes were treated with various antioxidants to determine the optimal concentrations and kind of antioxidants. Determined antioxidants were applied to oocytes during in vitro maturation (IVM) and/or SCNT procedures. Finally, antioxidant-treated SCNT embryos were compared with in vitro fertilized (IVF) embryos. H2O2 levels were analyzed in embryos at 20 h of activation, fusion or insemination by staining of embryos in 10 μM 2'7'-dichlorodihydrofluorescein diacetate (H2DCFDA) dye, followed by fluorescence microscopy. H2O2 levels of parthenogenetic embryos were significantly lower in 25 μM β- mercaptoethanol (β-ME), 50 μM L-ascorbic acid (Vit. C), and 50 μM L-glutathione (GSH) treatment groups than each control group (24.0±1.5 vs 39.0±1.1, 29.7±1.0 vs 37.0±1.2, and 32.9±0.8 vs 36.3±0.8 pixels/embryo, p<0.05). There were no differences among above concentration of antioxidants in direct comparison (33.6±0.9~35.2±1.1 pixels/embryo). Thus, an antioxidant of 50 μM Vit. C was selected for SCNT. H2O2 levels of bovine SCNT embryos were significantly lower in embryos treated with Vit. C during only SCNT procedure (26.4±1.1 pixels/embryo, p<0.05) than the treatment group during IVM (29.9±1.1 pixels/embryo) and non-treated control (34.3±1.0 pixels/embryo). Moreover, H2O2 level of SCNT embryos treated with Vit. C during SCNT procedure was similar to that of IVF embryos. These results suggest that the antioxidant treatment during SCNT procedures can reduce the ROS generation level of SCNT bovine embryos.
        4,000원
        151.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적: 전기분해 자동분석법(polarographic method)을 이용한 산소침투성 측정장비의 신뢰도를 평가하 고, 하이드로겔 및 실리콘 하이드로겔 콘택트렌즈 재질들의 산소침투성(Oxygen permeability; Dk)을 측정 하여 제조사에서 제시된 값과 비교하고자 하였다. 방 법: Dk 값이 제시되어 있는 -3.00D의 하이드로겔 및 실리콘 하이드로겔 재질의 콘택트렌즈 8종을 선 정하고, 전기분해 자동분석기를 이용하여 산소침투성을 측정하였다. 각 측정 표본은 국제표준화기구(ISO) 규정에 따라 측정하고 Fatt와 Chasten의 계산식을 이용하여 보정하였다. 결 과: 8종의 시료 가운데 5종은 제조사에서 제시한 Dk 값보다 약간 높게 측정되었으며, 3종은 제조사에 서 제시한 값보다 다소 낮게 측정되었다. 한 가지 두께의 측정값을 이용하여 계산한 Dk 값과 여러 가지 두 께의 측정값들을 이용하여 계산한 Dk 값은 큰 차이가 있었으며, 여러 가지 두께의 측정값들을 이용하여 계 산한 Dk 값의 신뢰성이 더 높았다. 결 론: 3종의 콘택트렌즈는 제조사에서 제시한 Dk 값보다 다소 낮게 측정되었으나, 편차를 감안한 값들 의 일부는 제시된 Dk 값을 기준으로 ISO에서 정한 오차 범위 안에 포함되어 있었다. 본 연구에 사용된 전기 분해 자동분석기의 성능은 ISO 규격에 적합하며, Dk 값을 측정할 때 여러 가지 두께의 콘택트렌즈를 측정하 여 계산하는 것이 타당하다고 사료된다.
        4,200원
        152.
        2012.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        YBaCo2O5+δ조성의 산화물을 고상반응법을 이용하여 합성하였으며, 합성된 분말은 압축 성형 후 1,180℃에서 소결하여 치밀한 분리막을 제조하였다. YBaCo2O5+δ 분리막은 X-선 회절분석기(XRD)와 전자 주사 현미경(SEM)을 이용하여 분석하였다. XRD 분석결과 1,150℃ 이상에서 다른 불순물 없이 이중층 페롭스카이트 구조가 얻어졌다. 산소투과량은 분리막 양면에 산소분압 차이에 따라 750~950℃ 온도범위에서 측정하였다. 산소투과량은 온도와 산소분압이 증가할수록 증가하였고, 두께 1.0 mm의 YBaCo2O5+δ 분리막은 950℃, PO2 = 0.42 atm에서 약 0.15 mL/cm2·min의 최대 투과량을 보였다. 산소투과에 대한 활성화 에너지는 산소 분압이 감소할수록 감소하였고 PO2 = 0.21 atm의 조건에서 76.0 kJ/mol이었다.
        4,000원
        153.
        2012.03 구독 인증기관 무료, 개인회원 유료
        Recent studies indicate that reactive oxygen species (ROS) are critically involved in persistent pain primarily through spinal mechanisms, and that mitochondria are the main source of ROS in the spinal dorsal horn. To investigate whether mitochondrial ROS can induce changes in mem¬brane excitability on spinal substantia gelatonosa (SG) neurons, we examined the effects of mitochondrial electron transport complex (ETC) substrates and inhibitors on the membrane potential of SG neurons in spinal slices. Application of ETC inhibitors, rotenone or antimycin A, resulted in a slowly developing and slight membrane depolarization in SG neurons. Also, application of both malate, a complex I substrate, and succinate, a complex II substrate, caused reversible membrane depolarization and enhanced firing activity. Changes in membrane potential after malate exposure were more prominent than succinate exposure. When slices were pretreated with ROS scavengers such as phenyl-N-tert-buthylnitrone (PBN), catalase and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), malate-induced depolarization was significantly decreased. Intracellular calcium above 100 µM increased malate-induced depolarization, witch was suppressed by cyclosporin A, a mitochondrial permeability transition (MPT) inhibitor. These results suggest that enhanced production of spinal mitochondrial ROS can induce nociception through central sensitization.
        4,000원
        154.
        2012.03 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to examine the generation of reactive oxygen species (ROS) during micromanipulation procedures in bovine somatic cell nuclear transfer (SCNT) embryos. Bovine enucleated oocytes were electrofused with donor cells, activated by a combination of Ca-ionophore and 6-dimethylaminopurine culture. Oocytes and embryos were stained in dichlorodihydrofluorescein diacetate or 3'-(p-hydroxyphenyl) fluorescein dye and the H2O2 or ˙OH radical levels were measured. In vitro fertilization (IVF) was performed for controls. The samples were examined with a fluorescent microscope, and fluorescence intensity was analyzed in each oocyte and embryo. The H2O2 and ˙OH radical levels of reconstituted oocytes were increased during manipulation (37.2~49.7 and 51.0~55.2 pixels, respectively) as compared to those of mature oocytes (p<0.05). During early in vitro culture, the ROS levels of SCNT embryos were significantly higher than those of IVF embryos (p<0.05). These results suggest that the cellular stress during micromanipulation procedures can generate the ROS in bovine SCNT embryos.
        4,000원
        155.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Successful application of graphene requires development of various tools for its chemical modification. In this paper, we present a Raman spectroscopic investigation of the effects of UV light on single layer graphene with and without the presence of O2 molecules. The UV emission from a low pressure Hg lamp photolyzes O2 molecules into O atoms, which are known to form epoxy on the basal plane of graphene. The resulting surface epoxy groups were identified by the disorder-related Raman D band. It was also found that adhesive residues present in the graphene samples prepared by micro-mechanical exfoliation using adhesive tape severely interfere with the O atom reaction with graphene. The UV-induced reaction was also successfully applied to chemical vapor deposition-grown graphene. Since the current method can be readily carried out in ambient air only with UV light, it will be useful in modifying the surfaces of graphene and related materials.
        4,000원
        156.
        2012.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        다공성 La0.6Sr0.4Ti0.3Fe0.7O3-δ로 코팅된 Ba0.5Sr0.5Co0.8Fe0.2O3-δ 관형 분리막은 압출성형 및 dip coating 방법으로 제조 되었다. 코팅된 관형 분리막의 특성은 X-선 회절분석기(XRD)와 전자 주사 현미경(SEM)을 이용하여 분석하였으며, 분석결과 2mum의 다공성 코팅 층을 갖는 페롭스카이트 구조임을 알 수 있었다. 산소투과량 분석은 750~950℃ 범위에서 공급측과 투과 측을 대기 중 공기와 진공으로 하여 수행되었다. 다공성의 La0.6Sr0.4Ti0.3Fe0.7O3-δ로 코팅된 Ba0.5Sr0.5Co0.8Fe0.2O3-δ 관형 분리막의 산소투과량은 950℃에서 3.2mL/min·cm2로 코팅되지 않은 분리막보다 높게 나타났으며, 11일 동안의 장기 안정성 실험결과 코팅 층에 의해 안정성이 증가됨을 알 수 있었다.
        4,000원
        157.
        2011.12 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to examine the reactive oxygen species (ROS) generation levels and subsequent DNA damage in the bovine cultured somatic cells. Bovine ear skin cells were classified by serum starvation, confluence and cycling cells. Cells were stained in 10 μM dichlorohydrofluorescein diacetate (H2DCFDA) or 10 μM hydroxyphenyl fluorescein (HPF) dye to measure the H2O2 or ˙OH radical levels. The samples were examined with a fluorescent microscope, and fluorescence intensity was analyzed in each cell. H2O2 and ˙OH radical levels of cultured somatic cells were high in confluence group (7.1±0.7 and 8.4±0.4 pixels/cell, respectively) and significantly low in serum starvation group (4.9±0.4 and 7.0±0.4 pixels/cell, respectively, p<0.05). Comet tail lengths of serum starvation (148.3±5.7 μm) and confluence (151.1±5.0 μm) groups were found to be significantly (p<0.05) increased in comparison to that of cycling group (137.1±7.5 μm). These results suggest that the culture type of donor cells can affect the ROS generation, which leads the DNA fragmentation of the cells.
        4,000원
        158.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PrBa0.9Sr0.1Co2O5+δ 조성의 산화물을 고상반응법을 이용하여 합성하였다. 합성된 분말은 압축 성형 후 1,250℃에서 소결하여 치밀한 세라믹 분리막을 제조하였다. 제조된 PrBa0.9Sr0.1Co2O5+δ분리막은 XRD분석 결과 이중 페롭스카이트 (double perovskite)구조를 보였다. 밀봉재료로는 pyrex ring을 사용하여 가스누출 실험 및 산소투과 분석을 하였다. 산소투과량 분석은 850~950℃범위에서 측정되었다. 산소투과실험 결과, 투과량은 온도증가에 따라 0.15에서 0.32mL/㎠·min로 증가하였다.
        4,000원
        159.
        2011.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effect of oxygen on the shape memory characteristics in Ti-18Nb-6Zr-XO (X = 0-1.5 at%) biomedical alloys was investigated by tensile tests. The alloys were fabricated by an arc melting method at Ar atmosphere. The ingots were cold-rolled to 0.45 mm with a reduction up to 95% in thickness. After severe cold-rolling, the plate was solution-treated at 1173 K for 1.8 ks. The fracture stress of the solution-treated specimens increased from 450 Mpa to 880 MPa with an increasing oxygen content up to 1.5%. The fracture stress increased by 287MPa with 1 at% increase of oxygen content. The critical stress for slip increased from 430 MPa to 695 MPa with an increasing oxygen content up to 1.5 at%. The maximum recovery strain of 4.1% was obtained in the Ti-18Nb-6Zr-0.5O (at%) alloy. The martensitic transformation temperature decreased by 140 K with a 1.0 at% increase in O content, which is lower than that of Ti-22Nb-(0-2.0)O (at%) by 20 K. This may have been caused by the effect of the addition of Zr. This study confirmed that addition of oxygen to the Ti-Nb-Zr alloy increases the critical stress for slip due to solid solution hardening without being detrimental to the maximum recovery strain.
        4,000원