The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Barbara Demmigadams - One of the best experts on this subject based on the ideXlab platform.
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leaf orientation and the response of the xanthophyll cycle to Incident Light
Oecologia, 1992Co-Authors: William W. Adams, Magdalena Volk, Andreas Hoehn, Barbara DemmigadamsAbstract:Leaves from two species, Euonymus kiautschovicus and Arctostaphylos uva-ursi, with a variety of different orientations and exposures, were examined in the field with regard to the xanthophyll cycle (the interconversion of three carotenoids in the chloroplast thylakoid membranes). East-, south-, and west-facing leaves of E. kiautschovicus were sampled throughout the day and all exhibited a pronounced and progressive conversion of violaxanthin to zeaxanthin, followed by a reconversion of zeaxanthin to violaxanthin later in the day. Maximal levels of zeaxanthin and minimal levels of violaxanthin were observed at the time when each leaf (orientation) received the maximum Incident Light, which was in the morning in east-facing, midday in southfacing, and in the afternoon in west-facing leaves. A very sLight degree of hysteresis in the removal of zeaxanthin compared to its formation with regard to Incident Light was observed. Leaves with a broader range of orientations were sampled from A. uva-ursi prior to sunrise and at midday. All of the examined pigments (carotenoids and chlorophylls) increased somewhat per unit leaf area with increasing total daily photon receipt. The sum of the carotenoids involved in the xanthophyll cycle, violaxanthin + antheraxanthin + zeaxanthin, increased more strongly with increasing growth Light than any other pigment. In addition, the amounts of zeaxanthin present at midday also increased markedly with increasing total daily photon receipt. The percentage of the xanthophyll cycle that was converted to zeaxanthin (and antheraxanthin) at peak irradiance was very large (approximately 80%) in the leaves of both E. kiautschovicus and A. uva-ursi. The daily changes in the components of the xanthophyll cycle that paralleled the daily changes in Incident Light in the leaves of E. kiautschovicus, and the increasing levels of the xanthophyll cycle components with total daily photon receipt in the leaves of A. uva-ursi, are both consistent with the involvement of zeaxanthin (i.e. the xanthophyll cycle) in the photoprotection of the photosynthetic apparatus against damage due to excessive Light.
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leaf orientation and the response of the xanthophyll cycle to Incident Light
Oecologia, 1992Co-Authors: William W. Adams, Magdalena Volk, Andreas Hoehn, Barbara DemmigadamsAbstract:Leaves from two species, Euonymus kiautschovicus and Arctostaphylos uva-ursi, with a variety of different orientations and exposures, were examined in the field with regard to the xanthophyll cycle (the interconversion of three carotenoids in the chloroplast thylakoid membranes). East-, south-, and west-facing leaves of E. kiautschovicus were sampled throughout the day and all exhibited a pronounced and progressive conversion of violaxanthin to zeaxanthin, followed by a reconversion of zeaxanthin to violaxanthin later in the day. Maximal levels of zeaxanthin and minimal levels of violaxanthin were observed at the time when each leaf (orientation) received the maximum Incident Light, which was in the morning in east-facing, midday in southfacing, and in the afternoon in west-facing leaves. A very sLight degree of hysteresis in the removal of zeaxanthin compared to its formation with regard to Incident Light was observed. Leaves with a broader range of orientations were sampled from A. uva-ursi prior to sunrise and at midday. All of the examined pigments (carotenoids and chlorophylls) increased somewhat per unit leaf area with increasing total daily photon receipt. The sum of the carotenoids involved in the xanthophyll cycle, violaxanthin + antheraxanthin + zeaxanthin, increased more strongly with increasing growth Light than any other pigment. In addition, the amounts of zeaxanthin present at midday also increased markedly with increasing total daily photon receipt. The percentage of the xanthophyll cycle that was converted to zeaxanthin (and antheraxanthin) at peak irradiance was very large (approximately 80%) in the leaves of both E. kiautschovicus and A. uva-ursi. The daily changes in the components of the xanthophyll cycle that paralleled the daily changes in Incident Light in the leaves of E. kiautschovicus, and the increasing levels of the xanthophyll cycle components with total daily photon receipt in the leaves of A. uva-ursi, are both consistent with the involvement of zeaxanthin (i.e. the xanthophyll cycle) in the photoprotection of the photosynthetic apparatus against damage due to excessive Light.
Hyung-ki Hong - One of the best experts on this subject based on the ideXlab platform.
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Temporal characteristics of the optical shutter of a vertical alignment liquid crystal cell designed for obliquely Incident Light
Liquid Crystals, 2011Co-Authors: Hyung-ki Hong, Hyun-ho ShinAbstract:The simple configuration of a liquid crystal (LC) cell shutter has been investigated for the purpose of rapid switching time. The LC cell is designed to cater for oblique Incident Light with vertical alignment. A decrease in switch-off time is observed when the azimuth angle of the Incident Light is either parallel or perpendicular to the optical axis of the polariser and about 45° to the optical axis of the LC tilt. A LC cell having a larger extinction ratio has been devised in which retardation films are no longer required.
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Response time characteristics of optical shutter of vertical alignment liquid crystal cell for obliquely Incident Light
Liquid Crystals, 2009Co-Authors: Hyung-ki Hong, Moojong LimAbstract:The temporal transmittance of a liquid crystal (LC) cell shutter was investigated for various Incident angles to verify the possibility of a fast switching time. For a mono-domain vertical alignment (VA) cell, the switch OFF time in which the LC restores to its initial alignment state under no driving voltage is found to relate to the angle of the Incident Light. A decrease of switch OFF time is observed when the azimuth angle of the Incident Light approaches the azimuth angle of the LC optical axis. For a 4-domain VA cell, switch OFF time is observed not to decrease for any obliquely Incident angle.
Moojong Lim - One of the best experts on this subject based on the ideXlab platform.
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Response time characteristics of optical shutter of vertical alignment liquid crystal cell for obliquely Incident Light
Liquid Crystals, 2009Co-Authors: Hyung-ki Hong, Moojong LimAbstract:The temporal transmittance of a liquid crystal (LC) cell shutter was investigated for various Incident angles to verify the possibility of a fast switching time. For a mono-domain vertical alignment (VA) cell, the switch OFF time in which the LC restores to its initial alignment state under no driving voltage is found to relate to the angle of the Incident Light. A decrease of switch OFF time is observed when the azimuth angle of the Incident Light approaches the azimuth angle of the LC optical axis. For a 4-domain VA cell, switch OFF time is observed not to decrease for any obliquely Incident angle.
Hyun-ho Shin - One of the best experts on this subject based on the ideXlab platform.
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Temporal characteristics of the optical shutter of a vertical alignment liquid crystal cell designed for obliquely Incident Light
Liquid Crystals, 2011Co-Authors: Hyung-ki Hong, Hyun-ho ShinAbstract:The simple configuration of a liquid crystal (LC) cell shutter has been investigated for the purpose of rapid switching time. The LC cell is designed to cater for oblique Incident Light with vertical alignment. A decrease in switch-off time is observed when the azimuth angle of the Incident Light is either parallel or perpendicular to the optical axis of the polariser and about 45° to the optical axis of the LC tilt. A LC cell having a larger extinction ratio has been devised in which retardation films are no longer required.
William W. Adams - One of the best experts on this subject based on the ideXlab platform.
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leaf orientation and the response of the xanthophyll cycle to Incident Light
Oecologia, 1992Co-Authors: William W. Adams, Magdalena Volk, Andreas Hoehn, Barbara DemmigadamsAbstract:Leaves from two species, Euonymus kiautschovicus and Arctostaphylos uva-ursi, with a variety of different orientations and exposures, were examined in the field with regard to the xanthophyll cycle (the interconversion of three carotenoids in the chloroplast thylakoid membranes). East-, south-, and west-facing leaves of E. kiautschovicus were sampled throughout the day and all exhibited a pronounced and progressive conversion of violaxanthin to zeaxanthin, followed by a reconversion of zeaxanthin to violaxanthin later in the day. Maximal levels of zeaxanthin and minimal levels of violaxanthin were observed at the time when each leaf (orientation) received the maximum Incident Light, which was in the morning in east-facing, midday in southfacing, and in the afternoon in west-facing leaves. A very sLight degree of hysteresis in the removal of zeaxanthin compared to its formation with regard to Incident Light was observed. Leaves with a broader range of orientations were sampled from A. uva-ursi prior to sunrise and at midday. All of the examined pigments (carotenoids and chlorophylls) increased somewhat per unit leaf area with increasing total daily photon receipt. The sum of the carotenoids involved in the xanthophyll cycle, violaxanthin + antheraxanthin + zeaxanthin, increased more strongly with increasing growth Light than any other pigment. In addition, the amounts of zeaxanthin present at midday also increased markedly with increasing total daily photon receipt. The percentage of the xanthophyll cycle that was converted to zeaxanthin (and antheraxanthin) at peak irradiance was very large (approximately 80%) in the leaves of both E. kiautschovicus and A. uva-ursi. The daily changes in the components of the xanthophyll cycle that paralleled the daily changes in Incident Light in the leaves of E. kiautschovicus, and the increasing levels of the xanthophyll cycle components with total daily photon receipt in the leaves of A. uva-ursi, are both consistent with the involvement of zeaxanthin (i.e. the xanthophyll cycle) in the photoprotection of the photosynthetic apparatus against damage due to excessive Light.
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leaf orientation and the response of the xanthophyll cycle to Incident Light
Oecologia, 1992Co-Authors: William W. Adams, Magdalena Volk, Andreas Hoehn, Barbara DemmigadamsAbstract:Leaves from two species, Euonymus kiautschovicus and Arctostaphylos uva-ursi, with a variety of different orientations and exposures, were examined in the field with regard to the xanthophyll cycle (the interconversion of three carotenoids in the chloroplast thylakoid membranes). East-, south-, and west-facing leaves of E. kiautschovicus were sampled throughout the day and all exhibited a pronounced and progressive conversion of violaxanthin to zeaxanthin, followed by a reconversion of zeaxanthin to violaxanthin later in the day. Maximal levels of zeaxanthin and minimal levels of violaxanthin were observed at the time when each leaf (orientation) received the maximum Incident Light, which was in the morning in east-facing, midday in southfacing, and in the afternoon in west-facing leaves. A very sLight degree of hysteresis in the removal of zeaxanthin compared to its formation with regard to Incident Light was observed. Leaves with a broader range of orientations were sampled from A. uva-ursi prior to sunrise and at midday. All of the examined pigments (carotenoids and chlorophylls) increased somewhat per unit leaf area with increasing total daily photon receipt. The sum of the carotenoids involved in the xanthophyll cycle, violaxanthin + antheraxanthin + zeaxanthin, increased more strongly with increasing growth Light than any other pigment. In addition, the amounts of zeaxanthin present at midday also increased markedly with increasing total daily photon receipt. The percentage of the xanthophyll cycle that was converted to zeaxanthin (and antheraxanthin) at peak irradiance was very large (approximately 80%) in the leaves of both E. kiautschovicus and A. uva-ursi. The daily changes in the components of the xanthophyll cycle that paralleled the daily changes in Incident Light in the leaves of E. kiautschovicus, and the increasing levels of the xanthophyll cycle components with total daily photon receipt in the leaves of A. uva-ursi, are both consistent with the involvement of zeaxanthin (i.e. the xanthophyll cycle) in the photoprotection of the photosynthetic apparatus against damage due to excessive Light.
