Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"Photoprotection"”.
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Investigation of photoprotection of photosystem II by cytochrome b559
The objective of this project has been to study molecular mechanisms that plants use to avoid damage caused by excess light. Light that exceeds the photosynthetic capacity of a plant can impair the ability of photosystem II to evolve oxygen and can ultimately lead to degradation of proteins within …
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Photoprotection and chloroplast regulation in the green algae Chlamydomonas reinhardtii
Absorbed light energy in excess of a cell's photosynthetic capacity can lead to production of reactive oxygen species (ROS) causing cell damage and death. Plants and algae have evolved conserved photoprotective responses that, at the level of light harvesting, are collectively measured as …
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Characterising natural genetic variation in dynamic photosynthesis and photoprotection in sorghum
… of the balance between photosynthesis and photoprotection in dynamic light conditions. Utilising a high-throughput chlorophyll fluorescence technique, a panel of 869 field-grown sorghum accessions was screened for multiple traits related to NPQ kinetics over two growing seasons. An ensemble …
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Design and Synthesis of New Systems for Photoprotection and Solar Energy Storage
… study clarifies the key features for photoprotection revealing a simpler scaffold which retains these skills. The development of a novel and versatile synthetic procedure allows for the synthesis of a series of analogues with proved and efficient photoprotective capabilities. In …
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Light energy management in peach: utilization, photoprotection , photodamage and recovery. Maximizing light absorption in orchard is not always the best solution
… absorbed energy in the several utilization, photoprotection and photo-oxidation pathways. When recovery is permitted only few PSII remained un-repaired, although more net PSII damage is recorded in plants placed in full light. Even in this experiment, in over saturating light the main …
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Excited-state organic chemistry: Tuning photoprotective and photoredox properties
… on two main applications of photochemistry: photoprotection and photoredox catalysis. In the context of photoprotection, the synthesis, characterization and study of the properties of new photoprotective molecules against solar radiation are presented. Additionally, mechanistic investigations …
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The Photoprotective Role of Anthocyanin Pigments in Leaf Tissues
… that anthocyanins may not be necessary for photoprotection. Furthermore, the presumed dynamic interaction between anthocyanin synthesis and relative need for photoprotection has yet to be quantitatively described. These issues, among others, have stalled acceptance of a photoprotective …
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Structural Origins and Functions of Colour Diversity in Sea Slugs: Novel Photonic Architectures, Biological Roles, and Biomimetic Applications
… might have unique biological functions, from photoprotection in Sacoglossa to Batesian mimicry in Cephalaspidea and aposematism in Nudibranchia. In the case of Elysia viridis , I extended the study of the inorganic nanostructures producing the photonic colouration by examining its biogenesis. …
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Assessing the Photoprotective Effects of Fluorescent Sphingomyelin Against UVB Induced DNA Damage in Human Keratinocytes
… p53 and p21 levels [6]–[9]. Current methods of photoprotection include sunscreen, but controversy over safety of some active ingredients necessitates research into more natural alternatives [10]–[12]. In particular, 24 hour incubation with bovine milk sphingomyelin (BSM) has demonstrated …
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Potential Impacts of Climate Change on Photochemistry of <i>Zostera Marina</i> L.
… pathways and non-photochemical quenching for photoprotection, therefore increasing quantum yield of oxygen production. These findings explained how seagrasses resist photodamage in shallow high light environments, while maintaining long daily period of light-saturated photosynthesis to …
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From the ice to the open ocean : threats to phytoplankton productivity in the Antarctic marine ecosystem from a changing climate
… explores the processes of light acclimation, photoprotection and photoinhibition in Antarctic microalgae under different environmental stressors, comparing photophysiological responses of species known to inhabit the sea-ice, meltwater and pelagic regions of Antarctic waters. The …
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Protection mechanisms against excess light in Myrothamnus flabellifolius (Welw.)
… as a control, in the dark. The effects on the photoprotection mechanisms were assessed. Differences in water content, quantum efficiency of photosystem II. chlorophyll (a+b) content, carotenoid content. anthocyanin contents were measured during dehydration and rehydration. Ultrastructural …
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Structural colour in marine organisms: From nature to applications
… its potential roles in light management, such as photoprotection or enhancing photosynthesis. In the second part of this thesis, I study how some rod-shaped gliding bacteria, such as Flavobacterium IR1 or Cellulophaga lytica, which form highly ordered two-dimensional photonic crystals when grown …
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The photoprotective role of thermonastic leaf movements in Rhododendron maximum: potential implications to early spring carbon gain
… suggest that TLM are an important mechanism for photoprotection, allowing leaves of R. maximum to recover quickly during the early spring and maximize their early spring carbon gain.
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Enhancement of Carotenoid Biosynthesis and Antioxidant Responses in Diatoms by Light Modulation
… antioxidant molecules synthesis/activity and photoprotection. <br></br><br></br> Results showed the spectral light dependent activity of antioxidant enzymes such as ascorbate peroxidase, catalase, and superoxide dismutase. They act in complementarity of the antioxidant molecules synthesis. A …
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Growth, photophysiology and photosynthesis of two marine diatoms grown under predictable intra-diel light fluctuations
… by greater photodamage and energy investment in photoprotection. Higher NPQ in P. tricornutum reduced net photodamage compared with T. pseudonana. However, light harvesting and ETR in P. tricornutum appeared to be adapted to a lower light environment than T. pseudonana. Higher amplitude light …
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Spatial properties of photophobia
… appear to serve a "tandem" function of foveal photoprotection.</p><p>Spatial summation for photophobia to long-wavelength "orange" light was found to be linear and somewhat greater than that dictated by Piper's law. The spatial summation functions derived from broadband xenon-white lights are …
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Synthesis of corn-derived carbohydrate derivatives as effective multifunctional sunscreen
… To meet a significant demand for improved photoprotection, a broad-spectrum sunscreen with a high extinction coefficient has been desired. As part of our ongoing studies on isosorbide-cinnamate derivatives, this work have found they have great promise as multifunctional sunscreens, based on …
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Multi-scale Remote Assessment of Phenology of Photosynthesis and Productivity of Northern Forests
… seasonal variation of carotenoid pigments and photoprotection in both evergreen and deciduous trees and are good proxies of photosynthetic activity for parameterizing LUE models to improve the monitoring of photosynthetic phenology.
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Identification and Characterization of Genes Involved in Regulation of Ascorbate Metabolic Pathway(s) in Arabidopsis thaliana
… and phytohormones, stress resistance, photoprotection, cell division, senescence, and growth. To identify genes that may regulate vitamin C levels in plants, about 3000 activation-tagged Arabidopsis lines were treated with ozone, which is a power oxidizing agent. Two mutants were …
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