• 제목/요약/키워드: light adaptation

검색결과 188건 처리시간 0.024초

Astaxanthin Biosynthesis Enhanced by Reactive Oxygen Species in the Green Alga Haematococcus pluvialis

  • Kobayashi, Makio
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제8권6호
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    • pp.322-330
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    • 2003
  • The unicellular green alga Haematococcus pluvialis has recently attracted great inter-est due to its large amounts of ketocarotenoid astaxanthin, 3,3'-dihydroxy-${\beta}$,${\beta}$-carotene-4,4'-dione, widely used commercially as a source of pigment for aquaculture. In the life cycle of H. pluvialis, astaxanthin biosynthesis is associated with a remarkable morphological change from green motile vegetative cells into red immotile cyst cells as the resting stage. In recent years we have studied this morphological process from two aspects: defining conditions governing astaxanthin biosynthesis and questioning the possible function of astaxanthin in protecting algal cells against environmental stress. Astaxanthin accumulation in cysts was induced by a variety of environmental conditions of oxidative stress caused by reactive oxygen species, intense light, drought, high salinity, and high temperature. In the adaptation to stress, abscisic acid induced by reactive oxygen species, would function as a hormone in algal morphogenesis from veget ative to cyst cells. Furthermore, measurements of both in vitro and in vivo antioxidative activities of astaxanthin clearly demonstrated that tolerance to excessive reactive oxygen species is greater in astaxanthin-rich cysts than in astaxanthin-poor cysts or astaxanthin-less vegetative cells. Therefore, reactive oxygen species are involved in the regulation of both algal morph O-genesis and carotenogenesis, and the accumulated astaxanthin in cysts can function as a protective agent against oxidative stress damage. In this study, the physiological roles of astaxanthin in stress response and cell protection are reviewed.

Primary Production System in the Southern Waters of the East Sea, Korea III. Vertical Distribution of the Phytoplankton in Relation to Chlorophyll Maximum Layer

  • Shim, Jae-Hyung;Park, Jong-Gyu
    • Journal of the korean society of oceanography
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    • 제31권4호
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    • pp.196-206
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    • 1996
  • Vertical profiles of the chlorophyll ${\alpha}$, phytoplankton abundance, nutrients and sigma-t were compared with the vertical distribution of phytoplankton species in conjunction with $^{14}$C primary production in the Southern Waters of the East Sea, Korea. In the upper mixed layer the water column was only weakly stratified and ambient nitrogenic nutrient concentrations were markedly depleted. Dissolved silicate seemed to be another limiting nutrient in the surface layer. The occupation of different water depths by several dominant diatom species was well explained by the degree of silicification of each cell and the silicate concentration of ambient seawater. Subsurface chlorophyll maxima were continuously observed in the lower parts of the euphotic layer and the depth coincided with nutricline, supporting our view that chlorophyll maximum was sustained partially by enhancement of in situ growth of phytoplankton and partially by increase of cellular chlorophyll content. The persistence of chlorophyll maximum layer was attributed to the physiological adaptation of the phytoplankters to low light intensities and to the utilization of regenerated nutrients. Integrated water column production of organic matter by photosynthesis appeared to be better related to phytoplankton cell division than to the cell growth in terms of biosynthesis of pigments and other intracellular components.

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Morphology of Retinas and Lenses in the Fish of the Genus Zacco (Cypriniformes, Cyprinidae): Possible Relationship with Prey and Habitat

  • Lim, Jae-Won;Lee, Chung-Lyul;Lee, Moo-Sam
    • Animal cells and systems
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    • 제7권4호
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    • pp.331-335
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    • 2003
  • Vertebrates with different habitats have different proportions of visual cells, with the rod cells responding to scotopic vision and the cone cells responding to photopic and color vision in their retinas. The present work studied whether the kinds and arrangement patterns of the cone cells and interlocking morphology of the lens were related to the kind of preys and habitats in the genus Zacco. The retinas were observed by a light microscopy using H-E staining method and the interlocking formula of the lens fibers were investigated by a scanning electron microscopy. The interlocking formula of the lens fibers of Z. temmincki is an ' anchor and socket ' connection, and that of Z. platypus is a ' ball and socket ' connection. The cone cells of Z. platypus and Z. temmincki constituted compacted mosaic patterns of row type. Away from the center, the double and single cone cells gradually increased in diameter. Zacco temmincki had identical double cone cells and Z. platypus had non-identical double and single cone cells. The eyes of Z. temminckifeeding on a moving aquatic insects in relative limpid water and swift current of mid and upper stream have better resolution than that of Z. platypus feeding on mainly adhesive algae and some aquatic insects in slightly turbid water of mid stream.

The Developing of Sports Commentator Attribute Scale for Adaptation to ICT and New Media Platform Era

  • Choi, Eui Yul;Jeon, Yong Bae
    • International Journal of Internet, Broadcasting and Communication
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    • 제12권3호
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    • pp.163-170
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    • 2020
  • The purpose of this research is to organize panels centered on professional workers and experts in the sports media industry, identify structures and items of sports media commentators' attributes that conform to the present era through the collective agreement process, and evaluate the derived measures according to the scale development procedure. We would like to shed new light on the nature of commentators due to the rapid development of broadcasting technology and the emergence of new media platforms, the emergence and expansion of smart media receptors and the changing environment of modern sports broadcasting. For this purpose, a panel of experts from academia and industry related to sports management and sports media was organized and the attributes of commentators were analyzed using the Delphi method. Technology development in the sports market has created a new sports consumption environment. In these consumer environments, various environmental factors influence the consumer's consumption culture of sports consumers. For example, professional information, as well as interpretations of sports culture, history and society are becoming their share for sports commentators, and viewers are demanding more diverse characteristics from sports commentators. In this respect, the study of sports commentator attributes can be a deep understanding of the rapidly changing culture of sports consumption.

자가결찰 브라켓과 골신장술을 이용한 구순구개열 환자의 치험례 (Cleft lip and palate patient treatment using self-ligating bracket and distraction osteogenesis: A case report)

  • 문철현;박선규
    • 대한치과의사협회지
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    • 제47권10호
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    • pp.656-668
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    • 2009
  • It is difficult to perform orthodontic treatment for cleft lip and palate patient. Although there are many orthodontic appliances to expand narrowed maxillary arch, results are rarely successful and the possibility of relapse is increased due to severe scars. Self-ligating bracket, recently used in orthodontic treatment, suggests solution of crowding by expansion of dental arches. Light and continuous force could apply for orthodontic movement due to characteristic low friction of self ligating bracket, which gives expansion force until dentition reaches its new equilibrium position and it can be expressed as spontaneous lateral expansion with heavy labial tension. This kind of expansion force is thought to be a possibility of expanding the constricted maxillary arch of cleft lip and palate patient. Repositioning of the maxilla by Le Fort I osteotomy in case of severe maxillary deficiency, increases the possibility of relapse because of limitation in anterior movement and adaptation of soft tissue. In these cases, distraction osteogenesis(DO) can be applied for stable result. We report a case of cleft lip and palate patient with narrowed maxillary arch and maxillary deficiency using self ligating bracket and DO.

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톰 브라운의 컬렉션에 나타난 패러디 (Parody Expressed in Thom Browne's Collection)

  • 장정임;이연희
    • 복식
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    • 제63권3호
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    • pp.61-77
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    • 2013
  • The purpose of this study is to analyze the concept and characteristics of parody, and consider how parody was reflected in Thom Browne's collection centering on the expressive method. Thus, this study will attempt to shed new light on the creative possibility and artistic value of parody in men's fashion design. The methods are as follows. The ideas, characteristics and expressive methods that represent parody was considered by referencing various related books, papers, art critiques, etc. Based on this theoretical study, a case of Thom Browne's collection (Thom Browne menswear: 2004 S/S-2012 F/W) was observed to find types of parody, attributes and significance. Photo material was collected through websites such as www.thombrowne.com, www.style.com, etc. The type and characteristics of parody expressed in Thom Browne's collection was considered in the following aspects: imitative parody, critical parody and pastiche parody. Through such consideration, it was possible to realize the fashion designs that adapt Thom Browne's parody are very deliberate and calculative. The designs convey exaggeration, destruction of form, emphasis on discontinuity, transition into attraction, aesthetics of unfamiliarity, characteristic aspects of irrationality and contradiction. Through the study, it was possible to see Thom Browne's collection with parody adaptation shaping new creativity and broadening formative aspects in fashion design.

사회구성주의와 비판적 사회구성주의 관점으로 본 다문화가정 주거의 실재 (Reality of Housing for Multi-Cultural Families from the Perspectives of Social Constructionism and Critical Social Constructionism)

  • 홍형옥
    • Human Ecology Research
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    • 제52권6호
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    • pp.573-586
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    • 2014
  • The purpose of this study was to review the conceptual framework of social constructionism and critical social constructionism in the research area of multi-cultural family homes, using a literature review. Fopp argued that social constructionism had an objectivation problem that only considered the actor side as a policy object; therefore he suggested a weaker social constructionist perspective with moderate relativism and the application of feminist epistemology to marginal life for maximizing objectivity. This article explores a conceptual framework for studying the reality of housing of multi-cultural families in Korea in the light of constructionist ideas and presents a review of empirical positivist data to support the framework. Based on results, using the social constructionist framework, five contexts (structural, institutional, organizational, operational, and intersubjective) were reviewed and ideas were suggested to develop an appropriate future situation for multi-cultural family homes. For a weaker social constructionist framework, three National Survey of Multi-Cultural Family Homes data sets were reviewed to determine the real condition of multi-cultural family homes. Further, from a feminist perspective, the empirical data of marginalized multi-cultural family homes were reviewed from the perspectives of gender inequality of decision making, cultural adaptation, and differentiation in housing related areas. In conclusion, two perspectives were useful for understanding multi-cultural family housing in Korea but must be compensated with substantial empirical data for a holistic approach.

간호사의 태움 체험에 관한 질적 연구 (Qualitative Research on Nurses Experiencing Taeoom)

  • 정선화;이인숙
    • 한국직업건강간호학회지
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    • 제25권3호
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    • pp.238-248
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    • 2016
  • Purpose: The purpose of this empirical research was to describe the contents what had happened to nurses experiencing taeoom. Methods: This study explored the phenomenological ways to understand lived experiences in nurses' 'Taeoom' and investigated the 'Taeoom' through the deductive content analysis. For the this study, the data was collected through individual interviews with 11 nurses who worked over 12months in 1 hospital, lived in 5 areas, working 7 nursing unit of 10 hospitals. The interviews conducted by semi structured questions about participants' lived experiences in 'Taeoom'. Results: Inductive contents analysis identified 5 categories and 15 subcategories. Main themes in this study included a failed membership, difficult of practical field adaptation, feared with nursing unit life, self-centered peer relationships and rite of passage. Conclusion: This study results have been illuminated with edged sword which has a dark side and a light side to experienced in 'Taeoom'. Newly employed nurses have suffering from 'Taeoom' as well as retained nurse. Therefore, policy and practice programs for a diminution of suffering and management for nurses 'Taeoom' should be developed and implemented.

Heme oxygenase-1 유도를 통한 화학 암예방 및 세포보호와 그 분자생물학적 기전 (Chemoprevention and Chemoprotection Through Heme Oxygenase-1 Induction and Underlying Molecular Mechanisms)

  • 김은희;김성환;나혜경;서영준
    • 한국환경성돌연변이발암원학회지
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    • 제26권4호
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    • pp.97-112
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    • 2006
  • Heme oxygenase(HO)-1 is an important antioxidant enzyme that plays a pivotal role in cellular adaptation and protection in response to a wide array of noxious stimuli. Thus, HO-1 induction has been associated with prevention or mitigation of pathogenesis of various diseases, including acute inflammation, atherosclerosis, degenerative diseases, and carcinogenesis. Recent progress in our understanding of the function of molecules in the cellular signaling network as key modulators of gene transcription sheds light on the molecular mechanisms underlyuing HO-1 gene expression. A panel of redox-sensitive transcription factors such as activator protein-1, nuclear factor-kB, and nuclear factor E2-related factor-2, and some of the upstream kinases have been identified as prime regulators of HO-1 gene induction. This review summarizes molecular mechanisms underlying HO-1 expression and the significance of targeted induction of HO-1 as a potential chemopreventive or chemoprotective strategy.

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Study on full color RGB LED source lighting for general lighting and Improvement of CRI (Color Rendering Index)

  • Park, Yung-Kyung
    • 감성과학
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    • 제15권3호
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    • pp.381-388
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    • 2012
  • The purpose of this study is to check if LED lighting can be used as general lighting and examine the color rendering property of full color RGB LED lighting. CRI is one of the important properties of evaluating lighting. However the present CRI does not fully evaluate LED lightings. Firstly, the performance of a simple task was compared other than comparing CRI values for different lighting. For experimental preparation three types of lightings were used; standard D65 fluorescent tube, general household fluorescent tube, and RGB LED lighting. All three lightings show high error for Purple-Red. All three lightings show similar error for all hues and prove that color discrimination is not affected by the lighting. This proves that LED could be used as general lighting. Secondly, problems of the conventional CIE CRI method are considered and new models are suggested for the new lighting source. Each of the models was evaluated with visual experiment results obtained by the white light matching experiment. The suggested model is based on the CIE CRI method but replaces the color space model by CIELAB, color difference model by CIEDE2000, and chromatic adaptation model by CAT02.

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