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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

UTILITY OF FOSSIL CUTICLE MORPHOLOGY APPLIED TO THE TAPHONOMY AND TAXONOMY OF DECAPOD CRUSTACEANS

Waugh, David A. 30 July 2013 (has links)
No description available.
2

Structure of the Royal Anne cherry cuticule with special reference to cuticular penetration

Wilson, Lester Arthur 12 August 1971 (has links)
The structure of the Royal Anne cherry cuticle (Prunus avium L.) and its penetration by a SO₂-calcium bisulfite brine was determined. The structural features of the cuticle are interpreted in the light of its possible significant to cuticular penetration. The morphology of the cuticle was determined by standard histological and histochemical techniques. The surface structure of the cuticle was studied with a scanning electron microscope. Enzymatically isolated cuticles were used to evaluate the effect of the cuticle on the penetration of the various components of brine. The surface of the cuticle was found to have a smooth to granular sheet or layer of surface wax which when removed revealed a porous sponge-like surface. The surface wax was found to be intermittently birefringent which increased as the fruit matured. Ectodesmata (MP) were found to occur over anticlinal walls and in guard cells on both sides of the fruit with more on the side opposite the suture. Both sides, were stomatous with more occurring on the suture side. Secondary bleaching was found to alter the structure and permeability of the cuticle. Removing the wax was found to increase percent weight loss as well as increasing cuticular penetration. Ion penetration was found to be generally greater from the outside to the inside than the inside to the outside surface and was greater from the side opposite the suture than the suture side. Potassium from potassium bitartrate was found to penetrate rapidly while SO₂, Ca⁺⁺, and H⁺ were delayed. It was concluded from this study that calcium penetration entered by a different route than SO₂; the major penetrating species of SOp in water and brine would seem to be molecular SCX and bisulfite ion; stomatal pores were not the sites of entry; ectodesmata were probably the sites for polar entry; the guard cells were more important for potassium penetration while ectodesmata in astomatous regions were more important for SO₂ penetration; and one of the major factors involved in penetration of brine is the waxy layer on the cuticle. Causes, preventative measures and recommendations for the structural defect known as "solution pockets" are discussed in light of the structure and penetration data. / Graduation date: 1972
3

Studies on the cells that secrete cuticular structures in invertebrates

Brunet, P. C. J. January 1952 (has links)
No description available.
4

Aspects of cuticle structure and formation in the fiddler crab, Uca spp.

Ridha, Mohammad M. T. M. January 1980 (has links)
No description available.
5

Aspects of cuticle structure and formation in the fiddler crab, Uca spp.

Ridha, Mohammad M. T. M. January 1980 (has links)
No description available.
6

Structural color in the scales of blue-banded bees /

Chen, Jiefei. January 2009 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2009. / Includes bibliographical references (p. 52).
7

Ecophysiological adaptations of cuticular water permeability of plants to hot arid biomes / Ökophysiologische Anpassungen der kutikulären Wasserpermeabilität von Pflanzen an heiße aride Biome

Bergmann Bueno, Amauri January 2021 (has links) (PDF)
Arid environments cover almost one-third of the land over the world. Plant life in hot arid regions is prone to the water shortage and associated high temperatures. Drought-stressed plants close the stomata to reduce water loss. Under such conditions, the remaining water loss exclusively happens across the plant cuticle. The cuticular water permeability equals the minimum and inevitable water loss from the epidermal cells to the atmosphere under maximally stomatal closure. Thus, low cuticular water permeability is primordial for plant survival and viability under limited water source. The assumption that non-succulent xerophytes retard water loss due to the secretion of a heavier cuticle is often found in the literature. Intuitively, this seems to be plausible, but few studies have been conducted to evaluate the cuticular permeability of xerophilous plants. In chapter one, we investigated whether the cuticular permeability of Quercus coccifera L. grown in the aridest Mediterranean-subtype climate is indeed lower than that of individuals grown under temperate climate conditions. Also, the cuticular wax chemical compositions of plants grown in both habitats were qualitatively and quantitatively analysed by gas-chromatography. In few words, our findings showed that although the cuticular wax deposition increased in plants under Mediterranean climate, the cuticular permeability remained unaltered, regardless of habitat. The associated high temperatures in arid regions can drastically increase the cuticular water permeability. Thereby, the thermal stability of the cuticular transpirational barrier is decisive for safeguarding non-succulent xerophytes against desiccation. The successful adaptation of plants to hot deserts might be based on finding different solutions to cope with water and heat stresses. Water-saver plants close the stomata before the leaf water potential drastically changes in order to prevent damage, whereas water-spender plants reduce the leaf water potential by opening the stomata, which allow them to extract water from the deep soil to compensate the high water loss by stomatal transpiration. In chapter two, we compare the thermal stability of the cuticular transpiration barrier of the desert water-saver Phoenix dactylifera L. and the water-spender Citrullus colocynthis (L.) Schrad. In short, the temperature-dependent increase of the cuticular permeability of P. dactylifera was linear over the whole temperature range (25-50°C), while that of C. colocynthis was biphasic with a steep increase at temperatures ≥ 40°C. This drastic increase of cuticular permeability indicates a thermally induced breakdown of the C. colocynthis cuticular transpiration barrier, which does not occur in P. dactylifera. We further discussed how the specific chemical composition of the cutin and cuticular waxes might contribute to the pronounced thermal resistance of the P. dactylifera cuticular transpiration barrier. A multitude of morpho and physiological modifications, including photosynthetic thermal tolerance and traits related to water balance, led to the successful plant colonisation of hot arid regions over the globe. High evaporative demand and elevated temperatures very often go along together, thereby constraining the plant life in arid environments. In chapter 3, we surveyed cuticular permeability, leaf thermal tolerance, and cuticular wax chemical composition of 14 non-succulent plant species native from some of the hottest and driest biomes in South-America, Europe, and Asia. Our findings showed that xerophilous flowering plants present high variability for cuticular permeability and leaf thermal tolerance, but both physiological features could not be associated with the species original habitat. We also provide substantial evidence that non-succulent xerophytes with more efficient cuticular transpirational barrier have higher leaf thermal tolerance, which might indicate a potential coevolution of these features in hot arid biomes. We further discussed the efficiency of the cuticular transpiration barrier in function to the cuticular wax chemical composition in the general discussion section. / Trockene Trockene Lebensräume bedecken fast ein Drittel der Landoberfläche der Erde. Das Pflanzenleben in Trockengebieten ist durch Wasserknappheit und hohe Temperaturen gekennzeichnet. Durch Trockenheit beanspruchte Pflanzen schließen die Stomata, um den Wasserverlust zu reduzieren. Unter diesen Bedingungen erfolgt der verbleibende Wasserverlust ausschließlich über die pflanzliche Kutikula. Die kutikuläre Wasserpermeabilität entspricht dem minimalen und unvermeidbaren Wasserverlust aus den Epidermiszellen an die Atmosphäre. Daher ist eine niedrige kutikuläre Wasserpermeabilität für die Lebensfähigkeit der Pflanzen unter begrenzter Wasserverfügbarkeit entscheidend. Die Annahme, dass xerophile Pflanzen den Wasserverlust aufgrund der Ausbildung einer speziellen Kutikula verringern, findet sich häufig in der Literatur. Intuitiv erscheint dies plausibel, jedoch wurden nur wenige Studien durchgeführt, um die kutikuläre Wasserpermeabilität von xerophilen Pflanzen zu untersuchen. Im ersten Kapitel wurde getestet, ob die kutikuläre Wasserpermeabilität von Quercus coccifera L., angezogen im ariden Klima des mediterranen Subtyps, tatsächlich geringer ist als die von Pflanzen derselben Art, die unter gemäßigten Klimabedingungen kultiviert wurden. Außerdem wurde die chemische Zusammensetzung der kutikulären Wachse von Pflanzen, die in beiden Habitaten angezogen wurden, quantitativ und qualitativ durch Gaschromatographie mit Flammenionisationsdetektion- beziehungsweise Massenspektrometrie-Kopplung analysiert. Die Ergebnisse zeigen, dass die kutikuläre Wasserpermeabilität unter beiden Anzuchtbedingungen vergleichbar war, obwohl die Pflanzen, die unter dem mediterranen Klima wuchsen, eine höhere Menge an kutikulären Wachsen aufwiesen. Die hohen Temperaturen in trockenen Regionen können die Wasserdurchlässigkeit der pflanzlichen Kutikula drastisch erhöhen. Dabei ist die thermische Stabilität der kutikulären Transpirationsbarriere entscheidend für den Austrocknungsschutz xerophiler Pflanzen. Die erfolgreiche Anpassung von Wüstenpflanzen kann auf verschiedenen Strategien zur Bewältigung von Wassermangel und Hitze beruhen. Wassersparende Pflanzen (water-save plants) schließen die Stomata, bevor sich das Wasserpotenzial drastisch ändert, um Schädigungen zu verhindern. Wasserverschwendende Pflanzen (water-spender plants) reduzieren das Wasserpotenzial durch das Öffnen der Stomata. Dadurch können diese Pflanzen Wasser aus tiefen Bodenschichte nachziehen, um den hohen stomatären Wasserverlust zu kompensieren. Im zweiten Kapitel wurde die thermische Stabilität der kutikulären Transpirationsbarriere der beiden Wüstenpflanzen Phoenix dactylifera L. (saver) und Citrullus colocynthis (L.) Schrad. (spender) verglichen. Der temperaturabhängige Anstieg der kutikulären Wasserpermeabilität von P. dactylifera verlief linear über einen Temperaturbereich von 25°C bis 50°C. Dagegen war der temperaturabhängige Anstieg der kutikulären Wasserpermeabilität von C. colocynthis zweiphasig. Der steile Anstieg der kutikulären Permeabilität bei Temperaturen ≥ 35°C weist auf eine thermisch induzierte Schädigung der kutikulären Transpirationsbarriere hin. Die spezielle chemische Zusammensetzung der Kutinmatrix und der kutikulären Wachse trägt zur ausgeprägten thermischen Resistenz der kutikulären Transpirationsbarriere von P. dactylifera bei. Die erfolgreiche Besiedlung von heißen und trockenen Regionen der Erde beruht auf einer Vielzahl von morphologischen und physiologischen Anpassungen wie der fotosynthetischen Hitzetoleranz. Eine hohe Verdunstungskapazität und hohe Temperaturen treten oft zusammen auf, wodurch das Pflanzenleben in ariden Klimazonen eingeschränkt wird. In Kapitel 3 wurde die kutikuläre Wasserpermeabilität, die kutikuläre Wachszusammensetzung sowie die fotosynthetische Hitzetoleranz von 14 nicht-sukkulenten Pflanzenarten aus einigen der heißesten und trockensten Biome Südamerikas, Europas und Asiens untersucht. Die Ergebnisse zeigen, dass die ausgewählten xerophilen Pflanzen eine hohe Variabilität in der kutikulären Wasserpermeabilität und der fotosynthetischen Hitzetoleranz aufwiesen. Beide physiologischen Merkmale konnten jedoch nicht mit dem ursprünglichen Standort der Arten assoziiert werden. Dennoch weisen xerophile Pflanzen mit einer effizienteren kutikulären Transpirationsbarriere eine höhere Hitzetoleranz auf, was auf eine mögliche Koevolution dieser Merkmale in trockenen Biomen hinweisen könnte. Darüber hinaus wurde die Effizienz der kutikulären Transpirationsbarriere in Zusammenhang mit der chemischen Zusammensetzung der kutikulären Wachse diskutiert
8

The cuticle of the parasitic nematode, `Nematospiroides dubius` / Lesley Clare Hurley

Hurley, Lesley Clare January 1986 (has links)
Bibliography: leaves 155-193 / iv, 193 leaves, [48] leaves of plates : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1986
9

Armet transcript knockdown in Tribolium castaneum

Bechard, Jarrod January 1900 (has links)
Master of Science / Biochemistry and Molecular Biophysics Interdepartmental Program / Gerald R. Reeck / Armet has been found in mammalian systems to be a bi-functional protein that is secreted extracellularly and is also found in the endoplasmic reticulum. It has been shown to be a neurotrophic factor and also a member of the unfolded protein response. Transcript knockdown of Armet via RNA interference in late instar larvae of Tribolium castaneum produces a fatal phenotype during eclosion from pupa to adult. Initial observations of pupae cuticle indicate disorganization of cuticles in insects with the Armet transcript knocked down. Here I expand studies on the effects of dsArmet RNA injection; both in a wild type strain and a fluorescent strain of Tribolium, and discuss possible mechanisms for the fatal phenotype.
10

Reflection and absorption of light in butterfly wing scales /

Zeng, Zheng. January 2008 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 62-63). Also available in electronic version.

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