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        검색결과 129

        62.
        2005.10 KCI 등재 구독 인증기관·개인회원 무료
        This study was to taken to demonstrate the effects of exogenous nitric oxide(NO) on hu rnan pu lp cell s ‘ In volvement of cyclic 3’, 5' -monophosphate(cGMP) in p버 paJ protection induced by herne oxygenase-l (J-lO-l) against NO-induced cytotoxicity , By use of Western blotting and cell viabi lity assay, we have examined the cytotoxicity and J-lO-l induction in pulp cells that were treated with NO donor ‘ S-nitroso-N-acetyl-D, L-penici 1 lamine(SNAP) , We have assessed wheathel' HQ--l contributes the cytoprotective effect against the cytotoxicity caused by NO, and inves tigated the l'elationship between HO-l and cGMP in the s ignaling pathway, SNAP decreased cell via bility but in creased HO-l expl'ession in a concentl'ation- and time一dependent manner in hurnan pu lp cells NO-induced cyto toxicity was inhibited in the presence of the hemin(inducer of HO-l) , whel'eas was en hanced in the pl'esence zinc protoporphyrin IX(ZnPP IX, HO-l inhibitor), thus Lhe NO-induced cytoLoxicity was cOl'related with HO- l expression. R‘ etreatment with a rnemhrane-permeable cGMP analog, 8-bromo-cGMP, restored cell death and enhanced the HO-l protein expression induced by SNAP, ln contrast‘ inhibition of guanylate cyclase by lI-l -[1,2,4] ox adiazole[ 4,3 口]quinoxalin-l-one(ODQ) pretreated pulp cells to 1 mM SNAP resulting in marked cytotoxicity , These findings , demonstrating a link between J-lO-l, regulated thl'ough the cGMP system and NO-induced cytotox.icity in huma띠 p버 p ceJls , suggesti ng a protective 1'ole of HO-l in pulp infl ammatory disease
        64.
        2004.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 콘크리트 교량의 지진취약도 곡선을 개발함에 있어 성능 스펙트럼 기법(Capacity Spectrum Method)에 대한 고찰을 통해 가장 적절한 해석방법을 제시하는데 그 목적이 있다. 원래 성능 스펙트럼 기법은 빌딩 구조물을 위한 간략화된 정적 비선형 해석의 일환으로 개발되었는 바, 본 연구에서는 이 기법을 교량의 지진취약도 곡선을 개발하는데 응용하였다. 서로 다른 네가지의 방법으로 성능 스펙트럼 기법을 통해 구해진 취약도 곡선들을 비선형 시간이력해석 방법에 의해 구해진 취약도 곡선과 비교하였다. 취약도 곡선은 두 개의 변수를 가진 lognormal 분포를 따르는 것으로 가정하였으며 PGA(Peak Ground Acceleration)의 함수로 나타내어졌다. FEMA(Federal Emergency Management Agency) SAC(SEAOC-ATC-CUREe) steel 프로젝트에 의해 개발된 로스앤젤레스 지역 60개의 지진이 교량해석을 위해 사용되었다. 성능 스펙트럼 기법과 시간이력해석에 따라 만들어진 교량의 지진취약도 곡선들을 비교 검토한 바, 이 중 하나의 방법이 부합되는 결과를 보여주었다. 요구 스펙트럼 작성시 본 논문에서 제시된 지침을 따르면 비선형 시간이력 해석시와 유사한 결과를 얻을 수 있을 것으로 사료된다. 다만 지진과 교량이 지닌 특수성으로 인해 본 연구의 결과가 항상 적용되는지는 더 심도있는 연구를 통해 검증되어야 할 것이다.
        4,000원
        65.
        2001.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have studied the nonlinear evolution of a magnetized disk of isothermal gas, which is sustained by its self-gravity. Our objective is to investigate how the Jeans, Parker, and convective instabilities compete with each other in structuring/de-structuring large scale condensations in such disk. The Poisson equation for the self-gravity has been solved with a fourth-order accurate Fourier method along with the Green function, and the MHD part has been handled by an isothermal TVD code. When large wavelength perturbations are applied, the combined action of the Jeans and Parker instabilities suppresses the development of the convection and forms a dense core of prolate shape in the mid-plane. Peripheral structures around it are filamentary. The low density filaments connect the dense core to the diffuse upper region. On the other hand, when small wavelength perturbations are applied, the disk develops into an equilibrium state which is reminiscent of the Mouschovias's 2-D non-linear equilibrium of the classical Parker instability under an externally given gravity.
        3,000원
        66.
        1998.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present B VRI CCD surface photometry for the central (6'.35 ×6'.35) regions of the dwarf elliptical galaxies NGC 185 and NGC 205 in the Local Group. Surface brightness profiles of NGC 185 (R<225") and NGC 205 (R<186") show excess components in the central regions. The colors of NGC 185 get bluer inward at R<25", while they remain constant at R ≥ 25". The colors of NGC 205 get bluer inward at 1"<R<50", and remain flat outside. Our photometry, supplemented by the photometry based on the far-ultraviolet and visual images of the HST archive data, shows that there is an inversion of color at the very nucleus region (at about 1"). The implications of the redder color of the core part of the nucleus compared with neighboring regions are discussed. The amount of the excess components in the central regions of these galaxies is estimated to be ≈10 5 L⊙. Distributions of dust clouds in the central regions of the two galaxies are also investigated.
        4,800원
        69.
        1996.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have analyzed infrared (IR) images of Jupiter which was observed at the McDonald Observatory, Texas, U.S.A., during the P/SHoemaker-LEvy 9 (SL9) impact period and about one week after the last impact. The IR images were obtained on the 2.7m telescope using a NICMOS array with filters to isolate the 1.5 μm NH3 band, the 2.3 μm CH4 band, the 2.12 μm H2 S(0) pressure-induced absorption, and the continua at 1.58 μm and 2.0 μm (short K-band). All images except those with the 1.58 μm continuum filter show bright impact sites against the relatively dark Jovian disk near the impact latitude of about 45° S. This implies that dusts originated from the impacts reflect the solar radiation at high altitudes before absorbed by stratospheric CH4, NH3 or H2. The impact sites observed with the 2.3 μm filter are conspicuously bright against a very dark background. The morphology of impact sites, G, L, and H at 2.3 and 2.12 μm filters shows clearly an asymmetric structure toward the incident direction of the comet fragments, in agreement with the studies of visible impact images obtained with the Hubble Space Telescope. Comparisons of reflectances of G, L, and H sites with simple radiative transfer models suggest that optically thick dust layers were formed at high altitudes at which methane absorption attenuates incoming sunlight only by about 1%. The dust layers in these sites seem to form at about the same altitude regardless of the magnitude of the impacts, but they appear to descend gradually after the impacts. The dust layers have optical depths of 2-5, according to the models.
        4,000원
        71.
        2018.05 KCI 등재 서비스 종료(열람 제한)
        물순환에 영향을 미치는 원인과 결과를 분석하는 기존의 연구들은 대부분 강우-유출모형을 사용하고 있어 모형의 구축 및 매개변수의 보정과 검증에 많은 노력이 필요하다. 본 연구에서는 수문기상자료만을 이용하여 유량의 변동성분을 정량화할 수 있는 수문학적 민감도 분석기법을 화천댐 상류유역에 적용하고 화천댐 유입량에 대한 1967~2017년 동안의 변동량을 자연적 요인과 인위적 요인으로 분리하여 제시하였다. 다양한 변동점 탐색기법을 사용한 결과 1999년이 통계적으로 유의한 변동점으로 탐색되었으며, 이를 활용하여 수문학적 민감도 분석을 5가지의 Budyko 함수들을 이용하여 산정한 결과 평균적으로 18.99억 m3/y의 유입량 감소가 임남댐 건설로 인하여 발생된 것을 알 수 있었다. 이와 같은 결과는 기존 연구자들의 화천댐 유입량 감소량에 비해 다소 크게 산정된 결과이며, 이는 2000년대 이후 증가된 강우량 및 화천댐 유입량의 감소가 주된 영향을 미친 결과로 추정된다. 향후 월별, 계절별 단위의 분석이 추가로 연구될 필요가 있으며, 미래의 기후변화 상황을 고려한 예측을 통한 실효성 있는 계획이 수립될 필요가 있을 것으로 판단된다.
        72.
        2018.04 KCI 등재 서비스 종료(열람 제한)
        흡연 유무의 남성을 대상으로 뇌 회백질의 손상 유무를 파악 할 수 있는 확산텐서영상을 검사하여 영상을 획득 한 후 Tract-Based Spatial Statics(TBSS)방법으로 뇌 회백질 부위의 기저핵 신경섬유로의 비등방도 FA(fractional anisotropy)값을 측정 분석한 결과 모든 영역에서 흡연자가 비흡연자보다 비등방성 측정값이 낮게 관찰되었으며 FA값은 통계적으로 유의하였다. 본 연구의 측정한 FA결과 값으로 추측하자면 즉, 흡연이 뇌 회백질 기저핵의 모든 해부학적 미세 구조성 변화에 크게 영향을 미치며 신경 섬유로를 손상시키고 이와 관련된 기능적 이상에 영향을 준다고 할 수 있다.
        73.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        본 연구는 원자력 발전소가 인접해 있는 부산지역 경찰관들의 원자력 사고와 방사능 테러에 대한 인식 과 대처 방안을 파악함으로써, 이와 관련한 정책 수립에 기초자료를 제공하고자 하였다. 부산광역시에 근 무하는 221명의 경찰을 대상으로 하였으며, 조직구성, 지휘능력, 여론운영 등으로 설문을 구성하여 재난대 응 인식도를 분석하였다. 그 결과, 성별 및 지휘계급에 따른 재난대응 인식은 큰 차이가 없는 것으로 나타 났다(p>.05). 연령의 경우 지휘능력에 대한 통계적 차이(p<.05)를 보였으며, 근무경력에 따른 지휘능력도 통 계적 차이(p<.05)를 나타냈다. 상관관계 분석 결과, 조직구성에 대한 인식과 지휘능력, 여론운영 3가지 항목 이 +0.5 이상으로 정적상관을 나타냈다(p<.01). 전반적으로 경찰 체제에 대해 긍정적인 것으로 나타났으며, 방사선사고 및 테러 발생 시 경찰의 업무를 잘 인식하고 있었다.
        74.
        2017.05 서비스 종료(열람 제한)
        Background : Insect pests damages are increasing on the field of Lycium chinense under eco-friendly organic management and especially, pest damage of Gelechiidae (Ilseopsis parki Povolny) is serious. Currently, various eco-friendly organic materials are registered, but insecticidal activity against Gelechiidae was not verified. Therefore, this experiment was carried out to select eco-friendly organic materials showing insecticidal activity in Gelechiidae. Methods and Results : To test insecticidal activity, the Gelechiidae lavas were collected from the field and Nine eco-friendly organic materials were collected from the market. method. The insecticidal activity assay method was, putting Gelechiidae lavas on the 90mm petridish then water-diluted eco-friendly organic materials were sprayed onto the laver. Result of insecticidal activity was observed with a microscope 10 minutes, 2 hours and 18 hours after the treatment. Microscopic observation results, insecticidal activity was shown only in 5 out of 9 materials. Conclusion : As a result, Insecticidal activity against Gelechiidae was not effective in all tested materials, but the 5 eco-friendly organic materials showed the same effect in repeated experiments. In this study, we selected 5 materials out of 9 eco-friendly organic materials against Gelechiidae, then future studies are planned to select the most suitable materials by field testing the 5 eco-friendly organic materials.
        75.
        2017.05 서비스 종료(열람 제한)
        Background : Tetraploid plants are bigger in the size of fruits, leaves, stems, and roots than diploid plants due to bigger cells attributed to chromosome multiplication. The advantage of tetraploid plants includes breakdown of self-incompatibility and increase of disease resistance. This study was carried out to gain tetraploid resources for breeding of new boxthorn varieties having pest resistance, higher yield, and self-compatibility. Methods and Results : Tetraploid lines and maternal varieties used in this study were C0148-10 and C0412-1 from Cheongyang-jaerae, M0148-94 and M0148-120 from Myongan, B0148-43 and B0148-78 from Bulro, D0148-62 and D0148-72 from Cheongdae, and Y0148-2 and Y0148-24 from Youngha. Betaine content was highest as 0.7 - 1.62% in leaf, followed by 0.55 - 1.17% in fruit and 0.04 - 0.23% in root. Betaine content in plant parts of several tetraploid lines increased compared to martenal varieties, higher in fruit for 5 lines including D0148-72, B0148-78, and C0142-1, higher in leaf for 5 lines including C0148-10, C0412-1, and M0148-94, and higher in root for 7 lines including Y0148-2, M0148-94, and M0148-120. Rutin content in leaf ranged 4.0 – 388.55 ㎎% and was highest as 388.55 ㎎% in Y0148-24. Tannin content in leaf of tetraploid lines was 4.70 - 6.12%, highest as 6.12% in Y0148-2 and M0148-120, similar to the maternal varieties. Youngha of the diploid plants showed the highest tannin content of 7.08%. Total free sugar content in tetraploid lines was higher as 8.53 - 12.53% than maternal varieties. Conclusion : Betaine and rutin contents increased in several tetraploid lines and Total free sugar content in tetraploid lines was higher as 8.53 - 12.53% than maternal varieties. This shows tetraploid boxthorn lines are very useful resources in breeding new varieties.
        76.
        2017.05 서비스 종료(열람 제한)
        Background : Rehmannia glutinosa is a perennial herb belonging to the family Scrophulariaceae. Its roots have been utilized as a traditional medicine but the aerial parts (flower, flower stalk, leaf) were not used. In this paper, we aimed to determine the content of three compounds [aucubin, catalpol, and γ-aminobutyric acid (GABA)] in different organs of R. glutinosa. Methods and Results : The flower, flower stalk, leaf, and root of R. glutinosa were harvested in the end of August. The aucubin and catalpol were analyzed by LC/MS, whereas GABA was analyzed by GC/MS. The aucubin content was the highest in the leaf, while catalpol and GABA were the highest in the flower. The aucubin content of in the leaf was 1.43, 0.81, and 1.07 ㎎/g, respectively. The catalpol content of flower in Dakang, Tokang, and Suwon 9 was 41.06, 28.78 and 37.48 ㎎/g, respectively. The GABA content of flower in Dakang, Tokang, and Suwon 9 were 0.79, 0.76 and 0.65 ㎎/g, respectively. Conclusions : The contents of aucubin, catalpol, and GABA were higher in leaf and flower than that of root. This study provides the important information of R. glutinosa leaf and flower as a potential supplement.
        77.
        2017.05 서비스 종료(열람 제한)
        Background : Recently, there have been dynamic researches conducted on stevia as natural sweetener subtitute for sugar, However, Researches related to harvest period and parts of plant in stevia are few. Therefore, this study was conducted to select optimum harvest time and parts by measuring the natural sweeteners contents and analyzing antioxidant materials and activity according to harvest times, parts of plant. Methods and Results : Stevia was cultivated in plastic house, The leaves were harvested from April to October and the stem were only harvest in July and September. Stevia leaves and stems were extracted using high temperature and pressure extraction: Dried stevia leaves of 5g were added by 100ml of distilled water equivalent to 20 times of dry weight, and the mixture were extracted by autoclave at 121℃ for 15min. The contents of Rebaudioside A and Stevioside of stevia leaves harvested from April to October showed a tendency to increase gradually from July to October as the temperature increased, but the contents of rebaudioside A and stevioside decreased slightly in August due to excessively high temperature. The extraction yield of stevia leaves were highest in October and September, and there was no significant difference in the other period. In the stevia stems, the extraction yield was lower than that of stevia leaves in general regardless of harvest time. Total phenolic contents and flavonoid contents according to harvest time showed little difference among treatment. Conclution : stevia leaves were better than stevia stems regarding the use of rebaudioside A and stevioside as natural sweeteners. Also, it was confirmed that the stevia leaves of July, September and October, except for the high temperature period of August, had superior in quality and quantity.
        78.
        2017.05 서비스 종료(열람 제한)
        Background : Stevia extracts were reported to contain steviol glycosides like stevioside and rebaudioside A, as well as various polyphenol compounds. However, there are many difference in researchers with extract methods, considering components and antioxidant activity. This study was conducted to select optimum extraction method based on reported methods by measuring the natural sweeteners contents, analyzing antioxidant materials and activity according to extraction methods. Method and Results : Stevia leaves were extracted through vacuum extraction, hot water extraction, soxhlet extraction, high temperature and pressure extraction and ultrasonic extraction to identify the high extraction efficiency. Extraction yield was high in order of hot water extraction, soxhlet extraction, high temperature and pressure extraction and ultrasonic extraction except for vacuum extraction and contents of rebauduoside A and stevioside in stevia leaves was highest in high temperature and pressure extraction followed by vacuum extraction, soxhlet extraction, hot water extraction and ultrasonic extraction. Also, total phenolic contents and flavonoid contents were highest in high pressure extraction and vacuum extraction according to extraction methods. But DPPH radical scavenging activity was highest in ultrasonic extraction and tended to be rather low in high temperature and pressure extraction (ultrasonic extraction > hot water extraction > high pressure extraction > soxlet extraction > vacuum extraction) and there wa no difference in ABTS radical scavenging activity among extraction methods. Conclusion : The high temperature and pressure extraction is considered to be a suitable method for extracting stevia leaves because it showed high extraction yield and had high contents of rebaudioside A, stevioside, total phenolic contents and flavonoid contents.
        79.
        2017.05 서비스 종료(열람 제한)
        Background : Currently, obesity and adult diseases as a result of sugar intake have been a consistent problem in Korea. Natural sweeteners as sugar substitutes have many advantages over sugar as a small quantity. Therefore, this study was conducted to investigate possibility of industrialization as food additives by using the nature sweetness components of stevia (Stevia rebaudiana Bertoni). Method and Results : Stevia was cultivated in a plastic house. The leaves and stems were harvested at October. They were ground into fine powder using a mill, and were extracted by high temperature and pression extraction method. The extracts were evaporated under vacuum and lyophilized. Three strawberry cultivars of ‘Seolhyang’, ‘Maehyang’, and ‘F22-196’ were cultivated in a plastic house and were harvested from March to May. The fruits harvested were stored at 50℃ until processing. In order to test the processing suitability of stevia extract, the characteristics of the three strawberry varieties (line) were investigated. As a result, the ‘F22-196’ line, which was bred as a processing strawberry, generally contained more antioxidant materials and activity than those of ‘Maehyang’ and ‘Seolhyang’ varieties. Comparing the sugar contents which affects the quality of strawberry jam, the average sugar contents of ‘F22-196’ line was higher than 'Maehyang' and 'Seolhyang' varieties. In the preparation of strawberry jam using ‘F22-196’, strawberry jam was prepared by adding only sugar or stevia extract powder, which was 1/100 of the amount of the sugar in only sugar strawberry jam, to the sensory test. As a result, we identified that sugar jam and stevia jam added stevia extract showed 50 : 50 at the sensory test and stevia jam does not make a difference to the marketing jam at the point of view of general consumers. Conclusion : ‘F22-196’ line represented the best quality for strawberry jam in test caltivars. Stevia powder is judged to be used as a sweetener of sugar substitutes in the production of strawberry jam and processing food.
        80.
        2017.05 서비스 종료(열람 제한)
        Background : The most problematic disease in Boxthorn is Anthracnose. New variety with Anthracnose-resistant is good for high yield and Safe fruit production in open field. Therefore it is necessary to develop a New variety with Anthracnose -resistant and high yield. Methods and Results : The new boxthorn line, CB10511-104 was selected from the cross between Cheongun (IT232599) and CB08456-113 to breed new variety with high yield and Anthracnose-resistant in 2011. Its preliminary yield test was performed from 2012 to 2013 and the selected line was named Cheongyang 25. Its regional yield trials were carried out in Cheongyang, Yesan and Jindo for 3 years, from 2014 to 2016. Cheongyang 25 was registered as the new variety, Cheonggeum, in 2016. The specific characteristics were summarized as follows; Tree shape is open type and the leaf is round-lanceolate. The flowers are normal size and purple. The fruit is large size, round oval and yellowish red. The flowering was June 19 with medium flowering. Number of sprout branch by pruning was generated more than the check variety, Cheongmeong. The infection rates on leaves to Eriophys macrodonis Keifer was as strong as 39.6 percent. Anthracnose on fruits in open field was slightly similare compared to the check variety, but check variety was Anthracnose-resistant. The content of betaine and free sugar in dried-fruits were higher than that of the check variety. The dried-fruit yield was decreased about 17 percent in open field. Conclusion : This variety ‘Cheonggeum’ was suitable for cultivation in open field because of Anthracnose-resistant. It is necessary the companion variety, Cheonghong, because of self-incompatible.
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