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        검색결과 533

        181.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적: 중심파장이 656.3nm에서 반치폭이 약 8nm이고 투과율이 92%인 협대역 H-α imaging 필터를 설계·제작하고, 이 필터의 박막 특성을 연구하고자 한다. 방 법: 전자빔 증착기를 이용하여 Ti3O5/SiO2 다층박막으로 656.3nm 대역투과필터와 Hb600 적외선 차단필터를 만든 후, 분광광도계로 투과율과 대역폭을 확인하였다. SEM사진을 이용하여 적외선차단필터 단면을 관찰하였고, XRD 데이터로부터 박막의 구조를 알 수 있었으며, XPS 분석으로부터 박막 성분을 확인하였다. 결 과: 협대역 H- imaging 필터에서 대역투과필터의 최적조건은 30층, 반사방지막 코팅층은 6층, 적외선차단필터는 32층으로 설계·제작되었다. 제작된 H- imaging 필터의 최대파장피크가 이론치에 비교했을 때 약 0.7nm로 공차가 거의 없는 것을 알 수 있었다. XRD 분석으로 대역투과 필터와 반사방지막 코팅층은 비정질로, 적외선 차단 필터는 결정질으로 코팅되는 것을 확인하였다. SEM 사진에 의해 적외선 차단필터의 코팅 층을 확인하였고, XPS 분석에 의해 대역필터의 가장 바깥층이 SiO2층임을 확인할 수 있었다. 결 론: Ti3O5/SiO2 다층박막을 이용하여 30층의 대역투과 필터와 32층의 적외선차단필터를 제작하여 657nm 중심파장에서 8nm 반치폭을 가지며 투과율은 92%인 협대역 H-α imaging 필터를 제작하였으며, 제작된 필터는 설계치와 거의 비슷한 투과율과 반치폭을 가짐을 알 수 있었다.
        4,000원
        182.
        2013.09 구독 인증기관 무료, 개인회원 유료
        Xylitol is a sugar alcohol with a variety of functions including bactericidal and anticariogenic effects. However, the cellular mechanisms underlying the role of xylitol in bone metabolism are not yet clarified. In our present study, we exploited the physiological role of xylitol on osteoclast dif-ferentiation in a co-culture system of osteoblastic and RAW 264.7 cells. Xylitol treatment of these co-cultures reduced the number of tartrate-resistant acid phosphatase (TRAP)- positive multinucleated cells induced by 10 nM 1α,25(OH)2 D3 in a dose‐dependent manner. A cell viability test revea-led no marked cellular damage by up to 100 mM of xylitol. Exposure of osteoblastic cells to xylitol decreased RANKL, but not OPG, mRNA expression in the presence of 10-8 M 1α,25(OH)2D3 in a dose‐dependent manner. Furthermore, bone resorption activity, assessed on bone slices in the co- culture system, was found to be dramatically decreased with increasing xylitol concentrations. RANKL and OPG proteins were assayed by ELISA and the soluble RANKL (sRANKL) concentration was decreased with an increased xylitol con-centration. In contrast, OPG was unaltered by any xylitol con-centration in this assay. These results indicate that xylitol inhibits 1α,25(OH)2D3-induced osteoclastogenesis by reducing the sRANKL/OPG expression ratio in osteoblastic cells.
        4,000원
        183.
        2013.09 구독 인증기관 무료, 개인회원 유료
        Tumor necrosis factor alpha (TNFα) is a multifunctional inflammatory cytokine that regulates various cellular and bio-logical processes. Increased levels of TNFα have been im-plicated in a number of human diseases including diabetes and arthritis. Sympathetic nervous system stimulation via the beta2-adrenergic receptor (β2AR) in osteoblasts suppresses osteogenic activity. We previously reported that TNFα up- regulates β2AR expression in murine osteoblastic cells and that this modulation is associated with TNFα inhibition of osteoblast differentiation. In our present study, we explored whether TNFα induces β2AR expression in human osteo-blasts and then identified the downstream signaling path-way. Our results indicated that β2AR expression was increa-sed in Saos-2 and C2C12 cells by TNFα treatment, and that this increase was blocked by the inhibition of NF-κB acti-vation. Chromatin immunoprecipitation and luciferase reporter assay results indicated that NF-κB directly binds to its cog-nate elements on the β2AR promoter and thereby stimulates β2AR expression. These findings suggest that the activation of TNFα signaling in osteoblastic cells leads to an upregu-lation of β2AR and also that TNFα induces β2AR exp-ression in an NF-κB-dependent manner.
        4,000원
        184.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Methotrexate의 영향은 혼탁매질에서 형광체, 산란체와 응흡수체에 의해 파장과 산란된 형광 세기로 규명되는데, laser induced fluorescence(LIF) 분광학에 의해 분자특성으로 나타난다. 산란매질에서 광학적 효과는 광학적 파라미터들((μs, μa, μt)에 의해 표현되고 응집은 고-액상 분리공정에서 중요하게 활용되고 있다. 따라서 입자가 서로 접근될 때 콜로이드 입자들의 상호작용을 LIF와 응집효과로 분석하였다. 산란계수는 산란매질, L-α-Phosphatidylcholine의 농도가 증가함에 따라 산란 광학적 파라미터가 증가하였으나 흡수 파라미터는 감소하였다. 광학적 파라미터들은 레이저 광원에서 검출기까지 깊이의 함수에 의해 깊이가 깊어짐에 따라 산란세기가 기하급수적으로 감소함을 알 수 있다. 이는 유지화학, 생의학 생성물, 레이저 의학, 의공학 분야적용에 LIF와 입자이동 현상은 아주 적합한 모델 연구에 큰 도움이 될 것이다.
        4,000원
        185.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract This manuscript reports on compared color evolution about phase transformation of α-FeOOH@SiO2 and β-FeOOH@SiO2 pigments. Prepared α-FeOOH and β-FeOOH were coated with silica for enhancing thermal properties and coloration of both samples. To study phase and color of α-FeOOH and β-FeOOH, we prepared nano sized iron oxide hydroxide pigments which were coated with SiO2 using tetraethylorthosilicate and cetyltrimethyl-ammonium bro- mide as a surface modifier. The silica-coated both samples were calcined at high temperatures (300, 700 and 1000°C) and characterized by scanning electron microscopy, CIE L*a*b* color parameter measurements, transmission electron microscopy and UV-vis spectroscopy. The yellow α-FeOOH and β-FeOOH was transformed to α-Fe2O3 with red, brown at 300, 700°C, respectively.
        4,000원
        186.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This manuscript reports on compared color evolution about phase transformation of α-FeOOH@SiO2 and β-FeOOH@SiO2 pigments. Prepared α-FeOOH and β-FeOOH were coated with silica for enhancing thermal properties and coloration of both samples. To study phase and color of α-FeOOH and β-FeOOH, we prepared nano sized iron oxide hydroxide pigments which were coated with SiO2 using tetraethylorthosilicate and cetyltrimethyl-ammonium bro- mide as a surface modifier. The silica-coated both samples were calcined at high temperatures (300, 700 and 1000°C) and characterized by scanning electron microscopy, CIE L*a*b* color parameter measurements, transmission electron microscopy and UV-vis spectroscopy. The yellow α-FeOOH and β-FeOOH was transformed to α-Fe2O3 with red, brown at 300, 700°C, respectively.
        4,000원
        187.
        2013.06 구독 인증기관 무료, 개인회원 유료
        Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causative microbes for nosocomial infe- ction and has been isolated from the dental environment. The purpose of this study was to investigate the antimi- crobial activity of linalool and α‐terpineol against MRSA isolates from a Korean population. In the experiments, we determined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these two compounds against 18 strains of MRSA. The data re- vealed that the MIC90/MBC90 values of linalool and α‐ terpineol against MRSA were >12.8 mg/ml and 6.4 mg/ml, respectively. These results indicate that α-terpineol has more potent antimicrobial activity against MRSA than lina- lool and may have utility as an anti‐MRSA cleansing agent for dental instruments and dental unit chairs.
        3,000원
        188.
        2013.04 구독 인증기관·개인회원 무료
        Previously, several levels of phylogenetic relationships in an insect order Odonata have been estimated using morphological and molecular markers. For the molecular phylogeny rRNA sequences were mainly, but other markers were not frequently employed. In this study, we sequenced both two mitochondrial genes (COI and 16S rRNA) and nuclear genes (28S rRNA and elongation factor-1α), composed of ~4,002 bp from 71 species of Odonata, occurring mostly in South Korea. These concatenated sequences were utilized to test the previous phylogenetic hypotheses of Odonata via Bayesian Inference (BI) and Maximum Likelihood (ML) algorithms, along with the data partition option available in BI method. Each families and superfamilies represented by multiple taxa consistently supported monophylies with the highest nodal supports in both Anisoptera and Zygoptera. A close relationship of Anisozygoptera to Anisoptera represented by a single species was obvious. On the other hand, familial relationships within each suborder of Anisoptera and Zygoptera have shown two compelling topologies. The topology obtained by BI method with partitioning of the four genes showed an unresolved relationship among Gomphidae, Aeshnidae, and the suborder Anisozygoptera in Anisoptera clade, presenting the relationships ((((Libellulidae + Corduliidae) + Macromiidae) + (Gomphidae + Aeshnidae + Anisozygoptera)) + (((Coenagrionidae + Platycnemdidae) + Calopterygidae) + Lestidae)). Another topology obtained by both BI and ML methods without partitioning, on the other hand, placed Anisozygoptera the basal lineage of Anisoptera, but Lestidae in Zygoptera was placed as the sister to Anisoptera + Anisozygoptera, presenting the relationships (((((((Libellulidae + Corduliidae) + Macromiidae) + Aeshnidae) + Gomphidae) + Anisozygoptera) + Lestidae) + ((Coenagrionidae + Platycnemdidae) + Calopterygidae)). Topological test to find out better supported tree turned out a slight higher support for the former topology, but the monophyly of Zygoptera with the inclusion of Lestidae was supported only poorly (BPP = 0.68) in the former topology.
        189.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alpha-tocopherol as an antioxidant acts in preservation of chilled semen by preserving cell membrane damage from lipid peroxidation. Optimum concentrations of α-tocopherol in egg yolk-citrate (EYC) extender need to be studied in crossbred bull’s semen. Different concentrations of α-tocopherol viz. 0, 1, 2, 4 and 6mg per ml of extender were used. Semen was collected once a week from four bulls used to regular collection, aged 4 to 7 years, weighing 320 to 450 kg, and with body condition score 4 to 4.5 and scrotal circumference 23 to 32 cm. Semen was evaluated routinely and sperm morphology was viewed under light microscope at ×1,000 magnification after fixing with buffered formal saline. Over 90% had normal head, acrosome, mid-piece and tail. Semen was diluted with egg-yolk-citrate extender to produce 15×106 spermatozoa/ml and 0, 1, 2, 4 and 6 mg/ml α-tocopherol were added. The semens amples were kept at 8℃. Sperm motility and viability were examined daily up to 5 days under light microscopy at ×200 magnification. Sperm viability was acceptable (≥40%) up to the 4th day with all concentrations of α-tocopherol and up to the 5th day with 2 mg/ml α-tocopherol. Sperm motility was acceptable (≥40%) up to the 3rd day irrespective of α-tocopherol concentration, and up to the 4th day with 2 mg/ml α-tocopherol. It is suggested that the lifespan of chilled semen may be extended up to 4 days by adding 2mg/ml α-tocopherol.
        4,000원
        190.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dynamic application lower mode response is of interest, however the higher modes of spatially discretized equations generally do not represent the real behavior. Some implicit algorithms, therefore, are introduced to filter out the high-frequency modes. The objective of this study is to introduce the P-method and PC α-method to compare that with dissipation method and Newmark method through the stability analysis and numerical example. PC α-method gives more accuracy than other methods because it based on the α-method inherits the superior properties of the implicit α -method. In finite element analysis, the PC α-method is more useful than other methods because it is the explicit scheme and it achieve the second order accuracy and numerical damping simultaneously.
        4,000원
        197.
        2012.10 구독 인증기관·개인회원 무료
        Bark beetles are recently considered as important forest insect pests in several countries. Damage of bark beetles has increased in Korea, and monitoring of these beetles become important. However, there has been no study on development of monitoring skill on bark beetles in Korea. In this study, we tested the attractiveness of (-)-α-pinene, ethanol, (-)-α-pinene+ethanol for monitoring of bark beetles. Some bark beetles strongly attracted to (-)-α-pinene or (-)-α-pinene+ethanol. Some ambrosia beetles strongly attracted to ethanol. Our results indicated that (-)-α-pinene, ethanol, or (-)-α-pinene+ethanol could be useful infochemicals for the monitoring of bark beetles.
        198.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 CCl4 존재하에서 Cl2(g) and ultra violet(200~300nm) 파장으로 maleic anhydride 와 Cl2(g)을 반응시켜 α,β-dichlorosuccinic acid 를 합성하였다. 그리고 두 번째 반응은 N-(α,β-dichloro)succinic acid 함유 glucosamine 유도체(I)를 합성하는 것으로 methanol 함유 2% acetic acid 용매 하에서 glucosamine과 과량의 α,β-dichlorosuccinic anhydride을 넣은 후 온도를 70℃로 올리면서 반응시켰다. 우리는 합성한 유기산 유도체들이 해태 김 재배와 피부미용에 주로 유용하게 활용할 것으로 본다.
        4,500원
        199.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper presents Hα emission line detections for four galaxies at z > 3.5 made with AKARI as part of the FUHYU mission program. These are the highest-redshift Hα detections to date in star-forming galaxies. AKARI's unique near-infrared spectroscopic capability has made these detections possible. For two of these galaxies, this represents the first evidence of their redshifts and confirms their physical association with a companion radio galaxy. The star formation rates (SFRs) estimated from the Hα lines under-predict the SFRs estimated from their far-infrared luminosities by a factor of ~ 2 - 3. We have also detected broad Hα components in the two radio galaxies which indicate the presence of quasars.
        3,000원
        200.
        2012.09 KCI 등재 구독 인증기관·개인회원 무료
        ANIR (Atacama Near InfraRed camera) is a near infrared camera for the University of Tokyo Atacama 1m telescope, installed at the summit of Co. Chajnantor (5,640 m altitude) in northern Chile. The high altitude and extremely low water vapor (PWV = 0.5 mm) of the site enable us to perform observation of hydrogen Paα emission line at 1.8751 μm . Since its first light observation in June 2009, we have been carrying out a Paα narrow-band imaging survey of nearby luminous infrared galaxies (LIRGs), and have obtained Paα for 38 nearby LIRGs listed in AKARI/FIS-PSC at the velocity of recession between 2,800 km/s and 8,100 km/s. LIRGs are affected by a large amount of dust extinction ( AV~ 3 mag), produced by their active star formation activities. Because Paα is the strongest hydrogen recombination line in the infrared wavelength ranges, it is a good and direct tracer of dust-enshrouded star forming regions, and enables us to probe the star formation activities in LIRGs. We find that LIRGs have two star-forming modes. The origin of the two modes probably come from differences between merging stage and/or star-forming process.