Dissertations / Theses: 'Naturally occuring'

1

Delashob, Hemen, and Björn Elmström. "Liquified Natural Gas Marine Fuel : Naturally Occuring Radioactive Material." Thesis, Linnéuniversitetet, Sjöfartshögskolan (SJÖ), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-84206.

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There seems to be enough information available on how different types of radiation may affect human health. There also seems to be adequate research made about NORM and how to handle this phenomenon. The image put forth by this study shows that the appearance of NORM within affected industries do not appear surprising or difficult to deal with. On the contrary it seems to be a well-known issue and safety measures have been adapted accordingly. It appears as if these issues have been overlooked regarding the systems where LNG is being used as a marine fuel. There is not enough data to conclude whether NORM is an issue or not in such systems.

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Jaunet, Alex. "Synthetic approaches to naturally occuring cyclohexenone epoxides." Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505527.

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Critchley, Trevor. "Synthetic studies towards naturally occuring antihypercholesterolaemic agents." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299552.

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Khan, R. A. "Synthesis of naturally occuring chromones and quinones." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1992. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3015.

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Toll, D. G. "The behaviour of unsaturated compacted naturally occuring gravel." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/8006.

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McErlean, Christopher Stephen Paschal. "Synthesis and biosynthesis of some naturally occuring oxygen heterocycles /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17082.pdf.

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7

Pooley, G. R. "Studies on the synthesis of naturally occuring cis-enynes." Thesis, University of Cambridge, 1991. https://www.repository.cam.ac.uk/handle/1810/272501.

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Green, Donald F. (Donald Frederick) 1969. "Haptic simulation of naturally occuring textures and soil properties." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9599.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.
Includes bibliographical references (p. 69-71).
Methods for developing realistic haptic (force feedback) simulations of soils and rocks are presented. Mathematical models of the dynamics of a virtual probe mechanically interacting with a virtual object are developed to provide the basis for analysis and simulation. The models then incorporate stochastic inputs in order to provide the haptic simulations with a more natural, less synthetic feel. The stochastic input parameters are derived by analyzing actual force data sensed while probing a subject media with the haptic display itself; in this case used as a force controlled manipulator. A method for sensing friction properties of rigid, textured surfaces and using the data collected to drive a realistic haptic texture simulation is presented. Static friction coefficients and surface height deviations a e sensed by directly stroking the surface under examination with a probe fitted on the end of a PHANToM haptic display device. Test surfaces range from pieces of sandpaper of varying coarseness to acetate. A simulation of the texture may then be rendered using the mechanical model of textured surface-probe interaction augmented by statistical variation of the friction properties of the surface. An algorithm is presented for adding texture properties to three-dimensional object models. The method is based on determining surface normals of the virtual object and assigning statistically varying friction properties and surface height deviations to area patches on the object's surface using the methods described above. Finally, a dynamic model of probe/soil interaction is used to render a haptic simulation of loose grained soils such as sand. Certain friction properties are again statistically varied in order to improve the realism of haptic display user's experience.
by Donald F. Green.
S.M.

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9

Mullins, Alastair Patrick. "The interaction of metal ions with naturally occuring phenolic compounds." Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306807.

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Macdonald, Gregor James. "The synthesis of naturally occuring antibiotics of the manumycin group." Thesis, University of York, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242164.

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11

Camling, Elisabeth. "Studies of naturally-occuring antibodies to mutans stretococci in humans." Göteborg : University of Göteborg, 1991. http://catalog.hathitrust.org/api/volumes/oclc/25384123.html.

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12

Bateman, Andrew. "Fast atom bombardment mass spectrometry in studies of naturally occuring peptides." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37631.

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Atkinson, Jeffrey K. "A structure-activity study of naturally occuring and synthetic cyclic hydroxamic acids." Thesis, University of Ottawa (Canada), 1989. http://hdl.handle.net/10393/21198.

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Inns, Elizabeth L. "The effect of heat treatment on the naturally occuring phenolic antioxidents of malt." Thesis, University of Reading, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413936.

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Champagne, Donald Edmond. "Allelochemical effects of naturally occuring polyacetylenes and thiophenes from the asteraceae on phytophagous insects." Thesis, University of Ottawa (Canada), 1985. http://hdl.handle.net/10393/4553.

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Chambers, Lily D. "The development of a marine antifouling system using environmentally acceptable and naturally occuring products." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/67336/.

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Due to legislative pressures and the recent ban of trybutyl tin, alternative environmentally acceptable ship hull antifouling systems are required. This thesis uses a multidisciplinary approach to combine two disparate areas of research namely marine biology and surface engineering, to develop a novel natural product (NP) based antifouling system. The overall objective of this thesis is to transfer a natural marine biological defence mechanism into an engineered antifouling coating system. By combining natural product extraction and incorporation into a trial coating an extensive test programme was able to investigate the antifouling performance and address the issues of bringing this active area of research to the next technological readiness level. By using a stepwise approach to the development of the engineered solution, a suite of techniques were used to fully characterise a NP based system. The biological and surface engineering techniques adapted and developed are described here and their future use to evaluate a novel NP based antifoulant system is critically assessed. After an extensive literature review, an ethanol extract from the red seaweed Chondrus crispus was selected as the natural product source. NP specimens were harvested locally and also purchased as industrially processed dried algae. The industrially processed algae showed good antifoulant activity ( ≤ 25 μg mL-1) in laboratory bioassays and had a greater efficacy than the locally harvested samples highlighting its potential as an economically viable solution. The direct incorporation of the NP into a commercial control depletion polymer binder, allowed for the rapid development of characterisation techniques to evaluate the effects this had on the performance of the NP-binder matrix. The feasibility of a range of electrochemical techniques to measure corrosion potential, impedance, resistance and water uptake in the NP coating was critically assessed. A combination of open-circuit potential and electrochemical impedance spectroscopy provided a unique and rapid means to non-destructively measure the contribution of incorporated NPs to the degradation and water uptake of the binder film. Studies of biofilm growth were used to successfully measure community viability and structure using fluorescent staining and differential interference contrast microscopy. These techniques were found to be very informative on Southampton water marine biofilm community structure and were cross correlated by fourier transform infrared measurements. Resistance to biofouling was determined through field trials, an important testing platform for an antifouling system, and specifically trials which test the entire coated system including any primers and substrate preparation requirements. An initial NP antifouling performance greater than the booster biocide (Chlorothalonil) control was documented for one field trial over a period of the first 6 weeks. A key aspect was to determine the potential efficacy of NPs and their viability in a coating system. To achieve this, a range of standard and non-standard techniques were used to assess this novel combination of crude NP extract and commercial binder system. This work has shown that a limited antifoulant activity is achievable. By evaluating the effect of a NP on both the fouling community and a binder system this unique approach helps define key techniques to assess future NP antifoulants and identifies the optimisation required to increase their functionality.

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Palmer, D. Gail. "Modulation of p53 expression and function in colorectal adenoma cell lines by naturally occuring factors." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265455.

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Higson, Seamus P. J. "Charge transfer reactions of some naturally occuring quinones across a novel biomimetic lipid model membrane." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316187.

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Almadi, Sejla. "The naturally occuring Pygmalion effect in the context of the CCE program : a new perspective." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0196.

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L'effet de Pygmalion au travail est intégré dans les cadres conceptuels des prophéties autoréalisatrices et des styles de leadership dans le domaine du comportement organisationnel. Son actualité se caractérise par un effet d’espérance interpersonnelle, son importance étant d’avoir un impact exceptionnel sur l’amélioration du leadership et la performance professionnelle des employés. Cependant, les préoccupations éthiques, phénoménales et méthodologiques de ses expériences ont soulevé des critiques. En réponse à cela, la thèse a proposé une nouvelle perspective à mettre en œuvre basée sur les trois dimensions du naturel (comportement, mise en place, traitement) et a émis l'hypothèse de l'occurrence naturelle de l’effet Pygmalion au travail. Par conséquent, la thèse visait à voir le test de la réalité, si et comment il est réalisé dans le contexte choisi du Programme d'Emploi de la Communauté culturelle. Il a appliqué une conception séquentielle exploratoire avec deux collectes de données: observation des participants (n = 25-130), questionnaires organisationnels (n = 1146-1155). L'analyse reposait sur des stratégies de quantification et de validité et prenait des statistiques descriptives et inférentielles. Les résultats ont contribué aux aspects théoriques et méthodologiques des recherches sur les effets de Pygmalion et de Galatea, à la question du contexte naturel et au programme étudié
The Pygmalion effect at work is embedded into the conceptual frameworks of self-fulfilling prophecies and leadership styles within the field of Organisational Behaviour. Its actuality lays in operating as an interpersonal expectancy effect, its significance lays in having an outstanding impact on leadership improvement and follower job performance. However, the ethical, phenomenal and methodological concerns of its experiments raised arguments. As a response to these, the dissertation proposed a new perspective to be implemented based on the three dimensions of naturalness (behaviour, setting, treatment) and hypothesized the naturally occurring Pygmalion effect at work. Therefore, the thesis aimed to see the test of reality, if and how it is realized in the chosen context of the Cultural Community Employment Program. It applied an exploratory sequential design with two data collections: participant observation (n=25-130), organisational questionnaires (n=1146-1155). The analysis was based on quantification and validity strategies, it took descriptive and inferential statistics. The findings contributed to the theoretical and methodological aspects of Pygmalion and Galatea effect researches, the issue of the natural context and the investigated program

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Rajanayagam, Brenda. "The potential of biomarkers as indices of response to naturally occuring toxicants (including those produced by cooking)." Thesis, University of Surrey, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264252.

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Tsomides, Theodore J. "Naturally occuring peptides recognized by cytotoxic T lymphocytes (CTS) : peptide abundance as a determinant of CTL function." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39757.

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Flanagan, Neal E. "Comparing ecosystem structure and function of constructed and naturally occuring wetlands: empirical field indicators and theoreticl indices." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1242846242.

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23

Lawson, Simon John. "A morphological study of naturally occuring and induced neuronal death in the developing spinal cord of the rat." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265974.

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Kurtz, Frederick C. "The mobility of malathion in a silt loam soil as affected by phosphate and naturally occuring organic acids." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/40648.

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Dodds, Catherine Jane. "The action of naturally-occuring semiochemicals on feeding behaviour and neurophysiology of the field slug Deroceras reticulatum (Mueller)." Thesis, University of Portsmouth, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310443.

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Naidu, S. V. "Asymmetric dihydroxylation and jacobsen’s hydrolytic kinetic resolution methods to the synthesis of naturally occuring amino alcohols and lactones." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2008. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2638.

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Santawamaitre, Todsadol. "An evaluation of the level of naturally occuring radioactive materials in soil samples along the Chao Phraya river basin." Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555934.

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The aim of this study was to evaluate the level of natural radioactivity in river sediments and riverbank surface soils collected along the Chao Phraya River and its tributaries in Thailand. The activity concentrations of naturally occurring radioactive materials in the 238U and 232Th decay chains and from 40K were determined by means of a gamma-ray spectrometry system using a hyper-pure germanium (HPGe) detector in a low background configuration. The ranges of activity concentrations of 238U, 232Th and 40K were found to be 13.9 ± 0.4 ~ 76.8 ± 1.7, 12.9 ± 0.3 ~ 142.9 ± 2.8 and 178.4 ± 6.1 ~ 810.7 ± 26.7 Bq.kg-1, respectively. The results of this current study have been compared with the world mean values of 35, 30 and 400 Bq.kg-1, respectively, specified by the UNSCEAR (2000). The artificial radionuclide, 137Cs, was not observed in statistically significant amounts above the background level in the current study. Additionally, the -, distribution of the activity concentrations to various particle sizes of soil was . investigated in this current study. It can be assumed from the results that the grain size or the fraction of sand and clay content is one of the factors that affects the activity concentrations of 238U and 232Th in the soil samples, while only a weak correlation between the activity concentration of 40K and the particle size in soil samples was observed in this current study. Concerning radiological risk to human health, the absorbed gamma dose rate (D) in air at 1 metre above the ground surface was estimated to lie in the range 21.7±0.4 to 155.7±2.2 nGy.h-1; the outdoor annual effective dose equivalent (AEDE) was evaluated to vary from 26.6±0.4 to 190.9±2.7 ~SV.il, with the arithmetic mean value of 79.06±33.23 ~Svf\ which is comparable to the worldwide effective dose of 70~Svfl. Also, the values of the Raeq and the Hex for all soil samples in the present work are lower than the accepted safety limit value of 370 Bq.ki1 and below the limit of unity, respectively. The results indicate that the radiation hazard from primordial radionuclides in all soil samples from the area studied in this current work is not significant.

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Stragar, Catherine E. "An assessment of two passive trap methods to sample naturally occuring bees at three different sites on the Delmarva Peninsula." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 24 p, 2007. http://proquest.umi.com/pqdweb?did=1597629181&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Wolenski, Francis S. "The NF-KAPPAB signaling pathway of the sea anemone Nematostella vectensis: functional characterization of core elements and two naturally occuring polymorphisms." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12677.

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Thesis (Ph.D.)--Boston University PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
The NF-κB family of eukaryotic transcription factors is activated in response to many environmental and biological stresses and is required for several important developmental processes. The sea anemone Nematostella vectensis (Nv) is the leading developmental and genomic model for the phylum Cnidaria, which includes anemones, hydras, jellyfish and corals. Sequencing of the Nematostella genome revealed sequences encoding NF-κB pathway proteins, including homologs of NF-κB, IκB, Bcl-3 and IKK. The goal ofthis research was to characterize molecular and biological functions of the Nv-NF-κB pathway proteins, in part because Nematostella is a model organism in which a framework for understanding the evolutionary origins of NF-κB signaling could be established. In this thesis, cDNAs for Nv-NF-κB pathway proteins were cloned and characterized. Nv-NF-κB is shown to bind to κB sites and activate transcription of reporter genes containing multimeric κB sites. Nv-NF-κB is localized in the nucleus of cells in developing Nematostella embryos and is expressed in the cytoplasm of a subset of ectodermal cells in juvenile and adult Nematostella. When over-expressed in human A293 cells, Nv-IκB and Nv-Bcl-3 can both interact with Nv-NF-κB and block its ability to activate reporter gene expression. Nv-IKK is most similar to human IKKc/TBK kinases, and can phosphorylate Nv-IκB in vitro. These results indicate that the core NF-κB pathway proteins in Nematostella are similar to their vertebrate homologs. This thesis also describes two geographically dispersed, naturally occurring NF-κB alleles in Nematostella. Proteins encoded by these two alleles, Nv-NF-κB-C and Nv-NF-κB-S, are polymorphic at key amino acids and have differing activities. Polymorphic residue 67 contributes to the difference between the two Nv-NF-κB variants in reporter gene transactivation. Computational modeling and electrophoretic mobility shift assays indicate that polymorphic positions 67 and 269 are responsible for differences in DNA binding of the two NF-KB variants. Additionally, the DNA-binding activity of Nv-NF-κB-C is more sensitive to redox conditions and thiol-reactive compounds than is the activity of Nv-NF-κB-S. These results suggest that environmental conditions, such as oxidative stress, have driven the divergence of the two alleles.

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Ridolfi, Danielle R. "Comparing to Perceived Perfection: An Examination of Two Potential Moderators of the Relationship between Naturally Occuring Social Comparisons to Peers and Media Images and Body Dissatisfaction." [Kent, Ohio] : Kent State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1254796796.

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Thesis (M.A.)--Kent State University, 2009.
Title from PDF t.p. (viewed April 7, 2010). Advisor: Janis Crowther. Keywords: body image; body checking; social comparisons; ecological momentary assessment. Includes bibliographical references (p. 68-77)

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Tang-Huau, Tsing-Lee. "Les cellules dendritiques inflammatoires humaines utilisent une voie non-cytosolique pour la présentation croisée Human naturally-occuring monocyte-derived dendritic cells cross-present antigens exclusively through a vacuolar pathway." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCB001.

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La présentation d'antigènes exogènes sur les molécules du CMH de classe I, appelée cross- présentation, est essentielle pour l'induction des réponses T CD8 cytotoxiques. La manipulation de la cross-présentation est une stratégie thérapeutique attrayante, mais une meilleure compréhension des mécanismes impliqués est essentielle. Dans les cellules dendritiques (DC) de souris, la cross- présentation se fait par la voie «cytosolique» ou «vacuolaire», en fonction de la localisation intracellulaire de la dégradation de l'antigène. Nous avons déjà montré que la DC résidentes dans les organes lymphoïdes humains présentait par la voie cytosolique. L'importance physiologique de la voie vacuolaire dans la DC humaine qui sont trouvés in vivo reste peu claire. Pour répondre à cette question, nous avons analysé la capacité de la DC dérivées de monocytes générée in vivo à cross- présenter. En utilisant le Single Cell RNA-seq, nous avons d'abord confirmé l'identification des ascites tumorales DC comme des cellules dérivées de monocytes. Nous avons trouvé que les ascites DC et les macrophages cross-présentent efficacement, mais sont incapables de transférer des protéines exogènes dans leur cytosol. De plus, l'inhibition du protéasome n'a pas affecté la cross-présentation. Ces propriétés n'étaient pas dues au microenvironnement tumoral, car les homologues in vitro des ascites DC et des macrophages présentaient les mêmes propriétés. Nous concluons que les cellules humaines dérivées de monocytes cross-présentent exclusivement par la voie vacuolaire. Enfin, nous avons trouvé que les DC dans l’ascite étaient aussi efficaces que les DC des amygdales pour l'induction des cellules T CD8 cytotoxiques effectrices, alors que les macrophages dans l’ascite étaient de mauvais stimulateurs des cellules T CD8. Ces résultats auront des implications importantes pour les stratégies thérapeutiques visant à moduler la cross-présentation
The presentation of exogenous antigens on MHC class I molecules, termed cross-presentation, is essential for the induction of cytotoxic CD8+ T cells. In mouse, dendritic cells (DC) that arise from monocytes (mo-DC) during inflammation play a key role in cytotoxic T cell responses by cross- presenting antigens directly in peripheral tissues. Whether human naturally-occuring mo- DC can cross-present is unknown. To address this question, we have used human mo-DC directly purified from peritoneal tumor ascites. Using single-cell RNA-seq, we first confirm that ascites DC contain exclusively monocyte-derived cells. Both ascites mo-DC and macrophages cross- present efficiently, but are unable to transfer exogenous proteins into their cytosol. Inhibition of cysteine proteases, but not of proteasome, abolishes cross-presentation by mo-DC. We conclude that human monocyte- derived cells cross-present exclusively using a vacuolar pathway. Finally, we demonstrate that only ascites mo-DC, but not macrophages, efficiently induce effector cytotoxic CD8+ T cells. These results will have important implications for harnessing cross-presentation for therapeutic purposes

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32

Kretzschmar, Tim [Verfasser]. "Effects of a synthetic serine protease inhibitor, camostat mesilate (FOY-305), on markers of pancreatic acinar cell damage, inflammation, and fibrosis in dogs with suspected naturally occuring chronic pancreatitis / Tim Kretzschmar." Berlin : Freie Universität Berlin, 2015. http://d-nb.info/1072410664/34.

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Nelson, Andrew Wyatt. "Naturally occurring radioactive materials associated with unconventional drilling for natural gas." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/5579.

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As unconventional drilling has emerged as a major industry in the US and around the world, many environmental health and pollution risks have surfaced. One emerging concern is the risk of environmental contamination arising from unconventional wastes that are enriched in naturally-occurring radioactive materials (NORM). Although NORM has been a well-documented contaminant of oil and gas wastes for decades, there are new challenges associated with unconventional drilling. This thesis discusses several of these challenges, focusing on NORM from black shale formations. Chapter 1 provides background information on environmental radioactivity and unconventional drilling. Chapter 2 describes the potential for NORM to migrate into groundwater around unconventional drilling operations. Chapters 3 and 4 describe radiochemical methods developed for the analysis of Marcellus Shale unconventional drilling wastes. Chapter 5 describes environmental partitioning of Marcellus Shale unconventional drilling wastes. Collectively, this thesis attempts to broaden the scientific understanding of NORM in unconventional drilling wastes so that potential environmental impacts may be mitigated.

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Thiel, Marco. "Recurrences exploiting naturally occurring analogues /." Phd thesis, [S.l. : s.n.], 2004. http://pub.ub.uni-potsdam.de/2004/0063/thiel.pdf.

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Ellis, Judith Ann. "Memory for naturally-occurring intentions." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329969.

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Jacob, Aouregan MicheÌ€le Marguerite Simone. "Synthesis of naturally occurring quinones." Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437087.

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Whiston, Keith. "Synthetic and naturally occurring ionophores." Thesis, University of Southampton, 1989. https://eprints.soton.ac.uk/388229/.

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Nielsen, Linda Birgitta. "Synthesis of some naturally occurring quinones." University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2009.0067.

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Naturally occurring quinones have attracted considerable interest due to their widespread occurrence, structural diversity and often potent biological activities. The research outlined in this thesis involves the development of synthetic approaches to two novel naphthoquinone derivatives, both of which were discovered during investigations into the bioactive constituents of tropical plant species. Chapter 1 introduces the family of quinonoid compounds and also considers the important role that natural product synthesis can play in structural confirmation and in providing an adequate supply of compounds for further research. Chapter 2 describes the synthesis of elecanacin 36, an unusual cyclobuta-fused naphthalene-1,4-dione derivative which has been isolated from the bulbs of the iris Eleutherine americana Merr. et Heyne (Iridaceae), along with the isomeric and well-known pyranonaphthoquinones eleutherin 38 and isoeleutherin 39. Chapter 3 focuses on an approach to 3-hydroxymethylfuro[3,2-b]naphtho[2,3-d]furan-5,10-dione 37, which has been isolated from the wood of the tropical tree Crescentia cujete L. (Bignoniaceae) and incorporates a rare fully aromatic furofuran moiety.

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Kaur, S. "Naturally occurring benzoporphyrins : structures and significance." Thesis, University of Bristol, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481605.

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Cairns, N. "Total syntheses of naturally occurring linear coumarins." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382619.

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Pouya, Caroline. "Investigating naturally occurring 3-dimensional photonic crystals." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/3744.

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This thesis describes my research into the highly tuned naturally occurring 3D photonic structures that are present on a selection of insects. The experimental and theoretical work presented in this thesis was performed in both the optical and microwave regimes. The work performed in the optical regime included both the geometric and optical characterisation of the native photonic structures present on the beetle Eupholus magni cus and the butter y Parides sesostris. The native photonic structures of these organisms were probed in order to determine their photonic responses and also to ascertain their geometries and structural classes. In cases where the geometry of a photonic crystal system has been determined, I have performed additional theoretical analysis of the structure to establish how it might be optimised for a particular optical function. The overall aim of the work performed in the optical regime is to further the understanding of the photonic structural designs present on a selection of beetles and butter ies, by both identifying and characterising their underlying structural geometries and consequent photonic responses. Eupholus magni cus is a species of weevil that produces its coloured appearance from photonic structures that are present on its outer wing casing, producing a striped coloured pattern. The photonic structures that I discovered were present on this weevil were found to be contrasting in structural order. I used a wide-ranging variety of experimental and theoretical techniques in order to perform an extensive electromagnetic and structural characterisation of these contrasting structures. The two contrasting photonic mechanisms employed by E. magni cus were found to produce a similar optical response in terms of angle-independent colour whilst re ecting di erent coloured hues. Parides sesostris is a species of butter y that uses a gyroid photonic crystal structure, contained within scales, to produce green coloured patches on the dorsal side of its wings. In addition to this, P. sesostris uses embellishments to its scale morphology in order to produce a highly tuned angle-independent optical response. The optical e ects brought about by these structural embellishments were investigated with optical experimental techniques and they were found to di usely scatter light and aid iridescence suppression. In addition to this, theoretical modelling was performed on a variety of gyroid geometries. The gyroid photonic structure found in the wing scales of P. sesostris was determined to be highly optimised to re ect the largest range of frequencies possible from this geometry, also aiding iridescence suppression. In addition to this, the arrangement of gyroid arrays within each scale was determined to produce the highest intensity possible by using the smallest possible number of unit cells. In addition to the optical characterisations of the organic naturally occurring photonic structures found on these organisms, I also synthetically replicated the three fundamental naturally occurring triply periodic bicontinuous cubic photonic crystal structures for experimental and theoretical electromagnetic characterisation in the microwave regime. The microwave regime was selected to perform the characterisation as a high-resolution fabrication method can be employed in order to produce millimetre-scale structures, suitable for probing in this wavelength regime. A high resolution fabrication method is an absolute requirement for accurately replicating the complex geometries of constant mean curvature structures and retaining a high level of detail. I have electromagnetically characterised these three structures with the aim of gaining a better understanding of their polarisation-dependent photonic stop-band responses. Speci cally, I have identi ed the origin of, and the dispersion of, photonic stop-bands produced by each unique structural geometry. I have principally focused on the characterisation of the electromagnetic responses of these structures, how they di er from each other and also why a linear polarisation dependence arises from these 3D photonic structures. In addition to this I have related the electromagnetic responses of these structures to analogous optical structures that naturally occur on the wings of the butter y P. sesostris and elytra of the weevil E. magni cus. With this I aimed to gain a better understanding of the origin of the optical e ects they provide the host biological system. This includes the characterisation of the gyroid photonic crystal structures, chosen to mimic that found in P. sesostris wing scales. The results from this were also subsequently used in the optical optimisation examination performed on the P. sesostris gyroid. Finally, I have investigated a dynamic aspect of the 3D gyroid photonic crystal, formed from a constant mean curvature surface. A compliant gyroid structure was fabricated for analysis in the microwave regime and a systematic compression force applied to it. I have measured the electromagnetic response of this compliant gyroid at each compression distance. Alongside this, I used theoretical modelling to electromagnetically characterise an analogous system under compression. In doing this I have identi ed the origin of the novel and complex photonic band-shifting behaviour produced by this 3D geometry.

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Hugo, Victor Ignatius. "Syntheses related to some naturally occurring naphthopyranquinones." Doctoral thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/17036.

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Bibliography: pages 248-257.
The naphtho[2,3-c]pyran ring system occurs not infrequently in Nature as derivatives of the 5,10-quinone. Examples include the eleutherins, the nanaomycins and the protoaphins some of which have been shown to possess antibiotic activity. The synthesis of these natural products requires appropriate regiospecific aromatic oxygenation of 2- acetylnaphthoquinone. Syntheses of 3-acetyl-5-methoxy-1, 4- naphthoquinone and the corresponding 5,7-dimethoxy analogue are described and the use of these in the syntheses of several naturally occurring pyranquinones or their derivatives, has been investigated. In the course of this work, an unusual Fries rearrangement and a novel baseinduced cyclisation were discovered - the latter affording several naphtho[2,3-c]pyrans in high yield. Previous routes to (±)-isoeleutherin and (±)-deoxyquinone A dimethyl ether have been recorded, but they give rise to a mixture of eleutherin and isoeleutherin in the first case, and a mixture of deoxyquinone A dimethyl ether and its cisdimethyl isomer. The synthetic routes to isoeleutherin and deoxyquinone A dimethyl ether developed during this investigation are highly stereoselective. The formation of the dimethyl ethers of quinones A and A', which is also highly stereoselective represents the first reported synthesis of the degradation products of the aphid pigments, protoaphin-fb and protoaphin-s1. The synthesis of 7-methoxyeleutherin is also described. The reaction of trifluoroacetic anhydride with various naphthalene derivatives is described and the potential of some of these acylated naphthalenes to be employed in the syntheses of naphtho[2, 3-c]pyrans and naturally occurring quinones has been investigated.

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George, S. N. "Human rhinovirus at naturally occurring COPD exacerbation." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1462147/.

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Chronic obstructive pulmonary disease (COPD) is an inflammatory condition of the lung caused by an abnormal response to particles and noxious gases, primarily cigarette smoke. Patients suffer daily symptoms and can have episodes of worsening symptoms termed acute exacerbations. Exacerbations are associated with impaired quality of life, faster lung function decline, higher mortality and increased risk of hospitalisation. The aetiology of COPD exacerbations is controversial; however respiratory viral and bacterial infections are an important feature of exacerbations. This study utilised real-time qPCR to measure prevalence and load of human rhinovirus (HRV) in stable COPD and during the time-course of naturally occurring exacerbations and their recovery. HRV was assessed in association with upper respiratory tract (URT) symptoms namely cold symptoms and sore throats, secondary bacterial infection, patient reported outcomes and exacerbation frequency. Additionally, respiratory syncytial virus (RSV) was semi-quantitatively examined in stable COPD and at exacerbation. The original contribution of this work to the field is that HRV prevalence and load are highest at exacerbation presentation and decrease during recovery. HRV load is higher in the presence of URT symptoms compared to the load without, and the load remains higher for longer with both symptoms compared to only one. This study described novel evidence for the development of secondary bacterial infection after HRV infection in natural exacerbations, and demonstrated that HRV infection is associated with patient reported outcomes. Patients with HRV had higher exacerbation frequencies compared to those without HRV. RSV prevalence did not change significantly between stable COPD and exacerbation. The findings from this thesis have important implications in terms of exacerbation therapy. The evidence provided may allow appropriate targeting of therapeutic interventions therefore reducing exacerbation severity and frequency. These findings emphasise the importance of rapid development of therapeutic targets for the prevention and treatment of HRV infection in COPD patients.

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BAIETTO, OLIVIERO. "Naturally Occurring Asbestos: the problem of quantification." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2737675.

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Gustafsson, Åsa. "Sorption and weathering properties of naturally occurring chlorites." Licentiate thesis, KTH, Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1819.

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Chlorite is a ferrous silicate mineral occurring as afracture filling mineral in the Swedish granite bedrock thatsurrounds the area of the candidate Swedish geologicalrepositories for nuclear waste.

To investigate the importance of chlorites as a naturalbarrier for radionuclide migration sorption of Ni(II) onto anatural chlorite was chosen as the studied system. The sorptionbehaviour was studied using batch technique under differentexperimental conditions by varying the concentration ofbackground electrolyte, pH and initial nickel concentration.Our experiments showed that sorption is dependent of pH; belowpH 4 no sorption occurs and in the pH range 7-11 the sorptionmaxima was found. The sorption shows no dependence of ionicstrength in our experiments and together with pH dependency weconclude that the sorption of nickel to chlorite is mostlyoccurring through surface complexation. The distributioncoefficient, Kd, was determined for our results and in the range formaximal sorption the Kdis approximately 10³cm³/g.

Our experimental data were described using a diffuse doublelayer model, including strong and weak surface sites, in thesoftware PHREECQ and the results obtained from PHREEQC werealso used for a fit of the data in the software FITEQL. Thesurface complexes that dominate the sorption of nickel tochlorite from our model are Chl_ONi⁺(weak) and for pH above 9 Chl_ONi(OH)^-(weak). Flow-through technique was used in ourinvestigations regarding the dissolution rate of a naturalchlorite and the experimental results show that the dissolutionrate of chlorite is strongly pH dependent and at pH 2 thehighest dissolution rate (R_Si) could be determined to 7• 10^-11mol/(m²s) based on silica data.

Keywords:chlorite, nickel, sorption, surfacecomplexation, dissolution rate.

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46

Constabel, Carsten Peter. "Studies on thiarubrine, a naturally occurring disulfide polyine." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27861.

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Chemical and biological aspects of thiarubrine, a highly antifungal dithiacyclohexadiene polyine, were investigated. A tissue culture system for the production of thiarubrines was developed by culturing hairy roots of Chaenactis douglasii induced by Agrobacterium rhizogenes strain TR7. One culture line accumulated two times the levels of thiarubrines of nontransformed control root cultures, while maintaining rapid growth. The combination of fast growth and high thiarubrine accumulation could not be duplicated in controls by adding exogenous NAA to the culture medium. Hairy root cultures also produced less thiarubrine B relative to thiarubrine A compared to controls. Thiarubrine synthesis appears to be closely correlated with degree of tissue differentiation; it is suggested that it may be more practical to improve the growth rate of thiarubrine-producing root cultures by transformation rather than seek to induce synthesis in fast-growing suspension cultures. The biosynthetic relation between thiarubrines and the always co-occurring thiophenes was investigated by performing ³⁵S tracer experiments with C. douglasii hairy root cultures. It is possible that the thiophenes are not actively synthesized by the roots but rather are products of thiarubrine decomposition resulting from the extraction procedures and other manipulations of the cultures. The in vitro conversion of thiarubrine to thiophene can be induced by light, heat and other agents. No turnover of thiarubrines could be detected in the cultures in late logarithmic or stationary phases of the growth cycle. I Thiarubrines show strong light-independent antibacterial and antifungal activity. The mechanism of action of thiarubrine against E. coli and S. cerevisiae was investigated using comparative disk bioassays. A very similiar polyine from Rudbeckia hirta was as active as thiarubrine in the dark, indicating the central role of the disulfide ring in toxicity of the compounds. Visible light enhanced this activity suggesting that decomposition of the disulfide ring is important for its antibiotic effects. The photodegradation product, a thiophene, is phototoxic, probably via both type I and type II photosensitization mechanisms. The root culture extracts of Rudbeckia hirta yielded a new isomer of a known dithiacyclohexadiene polyine. MS and NMR analyses confirmed the cis configuration of this isomer.
Science, Faculty of
Botany, Department of
Graduate

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47

Gustafsson, Åsa. "Sorption and weathering properties of naturally occurring chlorites /." Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1819.

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48

Bruder, Marjorie. "Synthesis of naturally occurring macrocyclic hydroquinones and oxephinochromones." Thesis, University of Nottingham, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523027.

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Rae, John Patrick. "Explanations and communicative constraints in naturally occurring discourse." Thesis, University of Leeds, 1989. http://etheses.whiterose.ac.uk/345/.

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The subject matter of this thesis are some aspects of the expression of explanations in spoken discourse. The study of explanations has occupied the attention of many researchers in social psychology and in neighbouring disciplines; the study of talk has occupied an even greater number. In the thesis I try to integrate certain areas of these two fields. Chapter one sketches the history of the concern with language which has characterised developments in the social sciences this century. This chapter is incidentally an introduction to some of the key themes of the thesis and to why I think research based on naturally occurring discourse is important. Research on explanations in social psychology has been dominated by research which has gone on under the heading of attribution theory. In chapter two I address a controversy in the application of concepts drawn from attribution theory to clinical psychology, namely whether or not people have fixed styles in the way that they attribute causes for outcomes. Studying family therapy sessions and interviews with parents with a coding procedure I show that the variety of possible styles is broader than has been suggested previously. Chapter three further pursues causal expressions as cases of explanations by asking what a causal statement is. The chapter opens with a discussion of how causes relate to reasons concluding that reasons are a species of cause. I then go on to use data from earlier work to study what expressions speakers use to make causal utterances. The direction of enquiry has been to suggest that rather than studying causal beliefs it is causal utterances that are under study. An utterance is, if you like, "situated", that is to say, what a speaker says is context-bound. I talk of "communicative constraints" operating here. Chapter four reviews some work in the study of conversation with an eye to elucidating the sense in which a speaker's utterances are a product of the situation in which they occur and to look at the researchability of this intuition. Practical and conceptual reasons suggest that the approach generally known as conversation analysis stemming from the study of ethnomethodology is the most interesting and fruitful way toproceed (in this context). Chapters five and six report studies of a computing advisory centre showing 1, the range of accounting procedures which occur as part of the business-at-hand in these sessions, 2, how speakers' utterances, can change within a single conversation. Chapter six looks at the integration of non-vocal behaviour and by considering data on this argues that the idea of normativity, rather than a quasi grammatical notion, is the appropriate level of explanation for the regularities which we find in human interaction. In moving away from beliefs as the object of analysis I could be accused of taking an anti-cognitive stance. Chapter seven explores cognitive versus interactional perspectives in communication. Chapter eight reflects on the approach which I have adopted and suggests how inspite, indeed through, its focus on situational events an account of the capacities drawn on in offering explanations can itself illuminate phenomena seen as beyond its grasp

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Higton, Sharon M. "Synthetic studies towards naturally occurring thiazoles and thiazolines." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240229.

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Dissertations / Theses on the topic 'Naturally occuring'

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