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Panagiotopoulou, Maria. "Organic-inorganic composite materials for specific recognition and optical detection of environmental, food and biomedical analytes." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2315/document.
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Cette thèse décrit l'état de l'art des sondes et nanoparticules fluorescents traditionnels utilisés en imagerie de fluorescence ainsi que le développement de nouveaux nanomatériaux à base de polymère à empreinte moléculaire, aussi dénommé ‘anticorps plastique’, pour le ciblage et la bioimagerie. En biologie et en médecine, il y a un besoin constant de diagnostiquer diverses maladies pour leur éventuel traitement et prévention. Une distribution anormale et un taux élévé de glycosylation (e.g. acides hyaluronique et sialique) à la surface ou dans les cellules sont indicateurs d’une infection ou d’un cancer. Généralement, l’imagerie par fluorescence permet de visualiser, localiser et quantifier les biomarqueurs de pathologie mais à l’heure actuelle, il n’existe pas d’outil analytique fiable pour cibler spécifiquement les molécules de glycosylation car les anticorps et les lectines vendus dans le commerce ont une faible affinité et sélectivité vis-à-vis de ces cibles. Dans ce contexte, les polymères à empreintes moléculaires (MIPs) pourraient apporter une solution. Les MIPs sont des récepteurs synthétiques possédant des affinités et sélectivités comparables à ceux des anticorps, mais exhibant une stabilité physique, thermique et chimique bien plus accrue. De plus, leur fabrication est peu coûteuse et ne nécessite pas de tuer des animaux comme pour l’obtention des anticorps biologiques. Dans cette thèse, nous avons optimisé et synthétisé des MIPs biocompatibles pour leur utilisation en bioimagerie afin de détecter et quantifier l’acide hyaluronique et l’acide sialique sur les cellules et les tissus de peau humaine. L’acide glucuronique, une composante de l’acide hyaluronique et l’acide N-acétylneuraminique, l’acide sialique le plus commun, ont été utilisés comme molécules ‘patron’, générant des MIPs très sélectifs envers leur cible en milieu aqueux. Deux types de nanoparticules de MIPs fluorescents ont été synthétisés: (1) en incorporant un colorant rhodamine polymérisable dans la solution de pré-polymérisation et (2) en encapsulant des boîtes quantiques InP/ZnS générant ainsi des MIPs de type cœur-coquille. Pour cela, nous avons adopté une stratégie innovante qui consiste à synthétiser les coquilles de MIPs directement autour des boîtes quantiques en utilisant l’énergie de l’onde fluorescente émise par l’excitation des points quantiques, pour initier la polymérisation. Un protocole d'immunocoloration standard a ensuite été optimisé afin d’imager des kératinocytes humains fixés et vivants ainsi que des tissus de peau, par microscopie à épifluorescence et confocale. Les résultats étaient similaires à ceux obtenus par la méthode de référence utilisant une protéine biotinylée reconnaissant l'acide hyaluronique. L'imagerie multiplex en combinant deux MIPs couplés à deux couleurs de boîtes quantiques et l’imagerie des cellules cancéreuses ont également été démontrées. Bien que les MIPs n’étaient pas cytotoxiques aux concentrations utilisées pour la bioimagerie, la toxicité des différentes composantes du MIP pourrait être un frein à leur utilisation dans le domaine biomédical. Afin de rendre ces MIPs plus ‘inoffensifs’, nous avons supprimé l’amorceur de polymérisation, une molécule considérée comme toxique. Les MIPs ont été synthétisés en employant des monomères qui s’auto-initient sous l’effet de l’UV ou de la chaleur. La spécificité et la sélectivité des MIPs obtenus étaient similaires à ceux préparés avec des amorceurs. En conclusion, cette thèse décrit la première utilisation des MIPs comme anticorps synthétique pour la bioimagerie de fluorescence. Ce travail ouvre la voie à de nouvelles applications en détection, diagnostique et thérapie par des MIPs<br>This thesis describes the state of the art in nanomaterials-based targeted bioimaging and introduces molecularly imprinted polymers, also termed ‘plastic antibodies’ as novel biorecognition agents for labeling and imaging of cells and tissues. In fundamental biology and medical diagnostics, there is a constant need to localize and quantify specific molecular targets. Abnormal glycosylation levels or distributions of hyaluronan or sialic acids on cells are indicators of infection or malignancy. In general, bioimaging with fluorescent probes enables the localization and qualitative or quantitative determination of these pathological biomarkers. However, no reliable tools for the recognition of glycosylation sites on proteins exist, because the commercially available antibodies or lectins have poor affinity and selectivity for these targets. In this context, tailor-made molecularly imprinted polymers (MIPs) are promising synthetic receptor materials since they present a series of advantages over their natural counterparts such as the ease and low cost of preparation and their physical and chemical stability. Thus, MIPs could provide a robust and specific imaging tool for revealing the location/distribution, time of appearance and structure of glycosylation sites on/in cells, which would lead to a better insight of the tremendously diverse biological processes in which these molecules are involved. Herein, we describe the synthesis of water-compatible MIPs for the molecular imaging of hyaluronan and sialylation sites on cells and tissues. Since molecular imprinting of entire biomacromolecules like oligosaccharides is challenging, we opted for what is commonly called the ‘epitope approach’, which was inspired by nature. The monosaccharides, glucuronic acid and N-acetylneuraminic acid were imprinted, and the resulting MIPs were able to bind these molecules when present and accessible on the terminal unit of hyaluronan and sialylation sites. Fluorescent MIPs were synthesized as rhodamine-labeled nanoparticles and as MIP-coated InP/ZnS core-shell quantum dot (QD) particles. For the coating of the QDs, a novel versatile solubilization and functionalization strategy was proposed, which consists of creating polymer shells directly on QDs by photopolymerization using the particles as individual internal light sources. A standard immunostaining protocol was then successfully adapted for the application of the fluorescently labeled MIPs to image fixed and living human keratinocytes and skin tissues, by epifluorescence and confocal fluorescence microscopy. The results were comparable to those obtained with a reference method where staining was done with a biotinylated hyaluronic acid binding protein. Multiplexed and cancer cell imaging were also performed, demonstrating the potential of molecularly imprinted polymers as a versatile biolabeling and bioimaging tool. Although the MIPs were not cytotoxic at the concentrations used for bioimaging, in order to render them generally applicable in biomedicine, where toxicity of the polymerization precursors is a matter of concern, we suppressed the initiator, a toxic chemical. Initiator-free MIPs were thus synthesized by using monomers that can self-initiate under UV irradiation or heat. The specificity and selectivity of the obtained MIPs were as good as the ones prepared with initiators. In conclusion, we have demonstrated for the first time the great potential of MIPs as synthetic antibody mimics for bioimaging. The possibility to associate other functionalities such as QDs and additionally attach drugs to the same material appears rather straightforward due to the synthetic polymeric nature of MIPs, which paves the way to new potential applications in theranostics
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Fuligni, Matteo. "PEDOT:PSS-based conductive Textile for simultaneous detection of sweat analytes." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21204/.
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This thesis is part of the wearable electronic field, and in particular of the Organic BioElecteonic Sensors that have the in-situ real-time monitoring of the health and performance status of the subject as the main goals.
With this purpose, textile-based wearable sensors for continuous and simultaneous detection of [Cl–] and pH level have been developed. PEDOT:PSS is the intrinsic conductive polymer used to make the commercial yarns conductive. The coated threads have been functionalized with Ag/AgCl NPs and BTB to make them
able to detect [Cl–] and pH level, respectively.
The developed sensors end up to be easy-to-make, reproducible with excellent sensitivity and stability both in single and multiple configurations without any interference. The results achieved in this work allow future improvements to develop a new textile-based device that can be easily integrated into clothing, allowing worn it in dealy life.
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Perez, Gregory Paul. "Chemically sensitive polymer-mediated nanoporous alumina SAW sensors for the detection of vapor-phase analytes." Texas A&M University, 2003. http://hdl.handle.net/1969.1/2202.
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We have investigated the chemical sensitivity of
nanoporous (NP) alumina-coated surface acoustic wave (SAW)
devices that have been surface-modified with polymeric
mediating films. The research in this dissertation covers
the refinement of the NP alumina coating, development of
dendrimer and/or polymer surface modifications, design of
composite ultrathin vapor-phase analyte gates, and
preparation of selectively permeable, polymeric films that
mediate analyte transport. Nanoporous alumina SAW devices were fabricated from planar Al SAW devices using an anodization process that yields a high-surface-area transduction platform. Refinement of the anodization process results in a homogeneously porous substrate capable of ~40 times the analyte sensitivity of conventional planar SAW devices. Attempts to directly impart selective gas-phase analyte permeation with monolayers of amine-terminated, poly(amidoamine) (PAMAM) dendrimer films were investigated with and without secondary functionalization. We also prepared and characterized pore-bridging
polymeric composite ultrathin films (~12 nm) of PAMAM
dendrimers and poly(maleic anhydride)-c-poly(methyl
vinylether) (Gantrez). Access to the underlying pores of
the NP alumina coating can be modulated through the
sequential deposition of the composite film. These
tailorable ultrathin films result in impermeable surface-
modifications which fully gate the analyte response without
filling the porous structure. Thin spin-cast films (40 nm) of polydimethylsiloxane (PDMS) were developed to simultaneously provide selective sorption and permeation characteristics towards vapor-phase analytes. The porous nature of the underlying alumina coating provides for this real-time evaluation of sorption and permeation. The results suggest that the thin films offer preferential sorption of non-polar organics and selective permeability towards water vapor.
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Al-Karawi, Dheyaa Hussein. "The Investigation of The Electrical Control of Hemimicelles and Admicelles on Gold for Analyte Preconcentration." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1732.
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Hemimicelles and admicelles are well-investigated wonders in modern science; they are surfactant monolayers and surface adsorbed micelles, respectively. Capacitance measurements for monitoring the formation of dodecyl sulfate (DS) surfactant monolayer on positively charged gold substrates (planar gold) and the adsorbance of 2-naphthol onto DS surfactant monolayer were performed. The investigation of the electrical control of DS at various concentrations (4, 6, 16, and 32 mM) below and above the critical micelle concentration (CMC= 8 mM) on gold surfaces for analyte preconcentration, prior to chromatographic analysis, is presented. Charged ionic surfactants, such as DS, drawn to a surface of opposite charge (porous nickel substrates coated with gold) serve as a stationary phase to trap organic analytes. It is believed that these DS assemblies gain stability through surfactant chain–chain interactions. The attachment and the removal of the surfactant are controlled using an electric field. Due to the fact that the surfactantanalyte association is released by electrical control, organic solvents, which are used in conventional solid phase extraction, are not required, making this procedure environmentally friendly. Electrical Impedance Spectroscopy was used to investigate the formation of the DS layer and the preconcentration of 2-naphthol in the presence of an applied electric field. High performance liquid chromatography was used to determine 2- naphthol concentrations. Anthracene and 9-anthracenecarboxylic acid were substituted as additional test molecules as well. Presented are the results of the preconcentration of 2-naphthol, anthracene and 9-anthracenecarboxylic acid using the DS layer with various concentrations of sodium dodecyl sulfate on a gold electrode surface.
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Heiman, Ross D. "Analyses of organic grain prices." Thesis, Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/176.
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McKay, Sarah Michele. "Understanding Organic Prices: An Analysis of Organic Price Risk and Premiums." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71677.
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Organic food products are produced without synthetic chemicals, including herbicides, pesticides, and fertilizers. Food grown in organic systems that are certified organic by the United States Department of Agriculture command a price premium, whether it is direct to consumer via farmers markets or in conventional grocery stores. Organic food and food products are representing a relatively larger portion of overall food sales in recent years, and the demand for organic meat has also increased. However, there is a lack of available U.S.-grown organic grains and soybeans to feed the growing number of organic certified livestock to produce organic meat to meet this demand. This shortage results from many factors, yet is primarily due to organic production requirements for significantly more land and operating capital when compared to conventionally grown counterparts. There is a lack of information detailing the relative costs and returns of organic grain production, and, limited understanding of organic premiums. The overall goal of this study is to examine differences in price levels between organic and conventional corn, soybeans, wheat, oats, and barley between 2007 and 2015, as well as factors that may affect the organic premium. For organic grain and soybean producers, study findings reveal that the least risky organic commodities to grow include corn and soybeans, especially if sold in the cash market. However, the author suggests that growers may consider growing wheat, barley, and oats if they have a buyer willing to contract in advance to ensure a premium and reduce price risk. For purchasers of organic grains and soybeans, including major food companies as well as livestock producers, it is recommended they continue to study developments in organic grain supplies as producers continue to consider adoption of organic production methods.<br>Master of Science
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Mogemark, Mickael. "Solid-phase glycoconjugate synthesis : on-resin analysis with gel-phase ¹9F NMR spectroscopy." Doctoral thesis, Umeå University, Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-438.
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<p>An efficient and versatile non-destructive method to analyze the progress of solid-phase glycoconjugate synthesis with gel-phase <sup>19</sup>F NMR spectroscopy is described. The method relies on use of fluorinated linkers and building blocks carrying fluorinated protective groups. Commercially available fluorinated reagents have been utilized to attach the protective groups. </p><p>The influence of resin structures for seven commercial resins upon resolution of gel-phase <sup>19</sup>F NMR spectra was investigated. Two different linkers for oligosaccharide synthesis were also developed and successfully employed in preparation of α-Gal trisaccharides and a n-pentenyl glycoside. Finally, reaction conditions for solid-phase peptide glycosylations were established.</p>
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Skinner, Diane Elizabeth. "Organising organic : a Foucauldian analysis of the regulation of organic food production." Thesis, University of Warwick, 2007. http://wrap.warwick.ac.uk/2850/.
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Early in the life of this thesis, Britain became the world's third largest consumer of organic produce with sales of organic food exceeding one billion pounds. Drawing on a conceptual framework based on Foucault's texts, the research investigates this little word "organic" and asks how organic food production is regulated. The empirical study begins with a genealogy/archaeology of organic farming regulation, including very recent history in the making during the research period. Using Foucault's concepts of code- and ethics-oriented morality and focusing on self-regulation, the study considers commitment to organic farming by producers as ethical subjects. An ethnography carried out within a self-managing cooperative organic farming community shifts the research to a local level. The research investigates the various organic truths produced by individuals through subjectivisation-objectivisation interplay. The code-oriented morality of the Soil Association is an absent presence that is at variance with a looser set of values and rules associated with the self-sufficiency movement and handed down as an oral tradition. Within a heterogeneity of organic, the care of the self practice parrhesia is used to analyse how community members establish collective organic farming practices through decision-making practices. The research uncovers the hidden complexities and ambiguities embedded in organic food production. The thesis reveals too how power relations are at play within the context of equality in a headless organisation. The thesis addresses the under-researched area of agriculture within business schools. Moreover, the thesis provides a comprehensive and accessible working example of Foucault's main themes and contributes to an emerging body of work based on the interplay of subjectivisation and objectivisation. Finally, the thesis contributes an empirical study of self-management to the emerging research field within Critical Management Studies of alternative organisational forms.
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Ndlovu, Bongani. "Kimberlite weathering : effects of organic reagents." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/33354.
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Diamonds are commonly present in an ore called kimberlite. Kimberlites vary extensively in mineralogy and therefore can complicate the processing and the extraction of diamonds. Weathering of kimberlite was investigated in this study and refers to the rapid physical breakdown of the kimberlite material. Kimberlite weathering by organic molecule adsorption was investigated utilising organic solutions; ethanol, formamide, n-hexane, oxalic acid, urea, pentanoic acid and acetic acid, was investigated. The extent of weathering was measured by XRD, TGA and FTIR analysis as well as by evaluating changes in the particle size distribution. The idea to predict the susceptibility of weathering of kimberlite based on TGA analysis was discredited as it was found that there was no correlation between the smectite content and the % weight loss from TGA analysis.
In XRD analysis studies to relate the d-spacing to the extent of weathering, it was found that the technique was not sensitive enough to enable direct prediction of weathering behaviour. Organic solutions at 0.5 M generally did not significantly alter the d-spacing. In the case of utilising pure organic solutions, it was observed that switching from diluted to pure organic solutions did not increase the d-spacings but rather lowers the space. Cation pretreatment prior to organic weathering resulted in d-spacings up to 2 water layers (12.6 Å being equal to 1 water layer, 15.6 Å equal to 2 layers and 18.6 Å equal to 3 layer). The general trend was that the divalent cations Mg2+ and Ca2+ increased the d-spacings whereas monovalent cations Na+ and K+ decreased the spacing. In the case of pre-organic treatment prior to organic weathering, it was observed that the resulting d-spacing increased to 2 and 3 water layers.
TGA analysis confirmed that the kimberlite structure did absorb organic reagents during weathering. It was observed that the amount of organic reagents adsorbed decrease in the following order: oxalic acid > urea > pentanoic acid > formamide > ethanol > n-hexane > acetic acid, with oxalic acid having been adsorbed the greatest. In addition, it was also shown that the extent of inorganic cation adsorption was more than that of organic solutions. The analysis also showed that organic pretreatments yielded promising results and the order followed was dimethyldioctadecylammonium chloride > cetylpyridium chloride > dodecylamine > pyridine in encouraging subsequent organic adsorption. FTIR analysis results indicated the mechanism by which organic molucules attached onto the mineral surface. It was observed that there was a disturbance of the bond between water in the interlayer and the silicate structure by a stronger H-bond gained through organic molecule attachment. Oxalic acid was observed to cause a structural change due to proton attack of the silicate structure.
It was found that kimberlite weathering, in essence, occurred in the first 24 hours of contact with the solution. Oxalic acid was found to be the most effective weathering agent compared to the rest of the tested organic solutions. The effect of the tested solutions, at 0.5 M concentration, on kimberlite weathering followed the series Cu2+ > oxalic acid > ethanol > acetic acid > formamide > n-hexane > distilled water. This study therefore showed that the accelerated weathering of kimberlite utilising organic solutions was not as efficient as the Cu2+ solution. Comparing Cu2+ and oxalic acid treatments, results showed that 67 % of the particles passed 12 mm screen size due to Cu2+ weathering as opposed to 48 % in oxalic acid.
In investigating the effects of variables, it was found that time of exposure had a small effect in the weathering of kimberlite. Increasing the organic concentration from 0.025 M to 0.5 M saw an increase in the amount of particles passing the 12 mm screen size by~20 %. There was however no improved weathering when the solution temperature was increased from approximately 25 °C to 40 °C.
In the study of kinetics involved during organic weathering utilising oxalic acid and comparing with Cu2+ medium, a high mineral dissolution was observed in the first 24 hours of contact with the weathering solution. However, different weathering mechanisms were observed between Cu2+ and oxalic acid. Inorganic solutions foster weathering by interlayer cation exchange which results in the reduction of the surface energy and this encourages further crack propagation. Oxalic acid weathering mechanism was by proton attack of the structural cations which was then limited thereafter by oxalate salts precipitation. Al3+ and Mg2+ were the dominant cations in solution during weathering (reaching 40 mmol/L) at higher oxalic acid concentration. This indicated that the dissolution of the clay‟s octahedral structure occurred, making oxalic acid a more effective agent than the rest of the tested organic solutions.
An alternative method to transform non-swelling clay minerals to swelling in kimberlites was highlighted. It was observed that cation exchange treatment in conjunction with acid and oxidation treatments on kimberlites containing non-swelling minerals: mica or forsterite that are at least 30 % in quantity may result in the presence of swelling clays after these treatments. Kimberlite that contained serpentine minerals was more resistant to alteration under these conditions.<br>Dissertation (MEng)--University of Pretoria, 2013.<br>gm2014<br>Materials Science and Metallurgical Engineering<br>UPonly
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Rugunanan, Rajan Anil. "Intersolid pyrotechnic reactions of silicon." Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1015571.
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A study of the role of different oxidants with silicon as the fuel in simple binary pyrotechnic compositions is reported. Several oxidants were examined, but only three (Sb₂0₃, Fe₂0₃ and Sn0₂) satisfied the restrictions that the combustion temperatures should be below the melting point of platinum/rhodium thermocouples (1760°C), that burning rates should not exceed the response of the thermocouples, and that burning should occur without significant mass-transport. A fourth oxidant, KN0₃, was selected on account of its low melting point and general importance as a pyrotechnic oxidant. The oxidation of silicon in the presence of either Sb₂0₃ or KN0₃ could be identified from thermal analysis curves. No thermal events were noted when Si/Sn0₂ and SiFe₂0₃ compositions were heated under similar conditions. The oxidation of Si powder in oxygen was also studied. All four binary systems sustained burning over a reasonably wide range of compositions. The range of burning rates measured (2 to 35 mm s⁻¹) depended on the oxidant used. Fe₂0₃ and Sb₂0₃ gave slow burning mixtures compared to Sn0₂ and to KN0₃ compositions with a high Si content. Burning rates generally increased with increasing specific surface area of silicon, but decreased in the presence of inert diluents and moisture. The burning rates of the Si/Fe₂0₃ and Si/Sn0₂ systems increased with increasing compaction of the samples. Kinetic parameters derived from the temperature proftles recorded during combustion were generally low (6 to 37 kJ mol⁻¹). This is in keeping with proposals that burning is diffusion controlled. The values of kinetic parameters derived from thermal analysis curves were considerably greater ( > 250 kJ mol⁻¹). Two other fuels, FeSi₇ and CaSi₂, gave similar thermal analysis curves when used instead of silicon. There were considerable differences in the burning rates for binary mixtures of these fuels compared to silicon. Ternary systems with two fuels or two oxidants showed that only limited interaction occurs during thermal analysis. The use of a second fuel or oxidant did, however, modify the burning behaviour considerably. Other techniques used in this study to probe the details of the reaction processes included bomb calorimetry, measurement of thermal conductivities, infrared spectroscopy, X-ray diffraction and scanning electron micoscropy.
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Lan, Zhaojue. "Spectral tunable organic near-infrared photodetectors." HKBU Institutional Repository, 2020. https://repository.hkbu.edu.hk/etd_oa/771.
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Filter-free spectral tunable photodetectors (PDs) are critical for a plethora of applications in imaging, indoor light fidelity (Li-Fi), and light communications. The present band-selective light detection is realized by incorporating different optical filters with broadband inorganic semiconductor-based PDs. However, the use of the optical filters reduces the overall performance of these PDs and is not appliable in the emerging flexible and wearable applications. The rapid advancement of the organic semiconductors offers an exciting opportunity for the development of high-performance filter-free spectral tunable organic photodetectors (OPDs). The development of OPDs has attracted tremendous interests because of the tailored optoelectronic properties of the π-conjugated organic semiconductors and the solution fabrication process of the OPDs. Apart from the rapid progresses made in improving the responsivity and detectivity of OPDs, the spectral properties of OPDs also receive intense attention. This Ph.D. research work has been focused on developing a universal strategy to achieve high-performance filter-free band-selective and spectral tunable OPDs. The correlation between the optical profile and responsivity spectrum of the novel OPDs with a bilayer photoactive layer has been investigated. It suggests that the responsivity spectrum of the OPDs can be effectively modulated by managing the optical profile in the bilayer and multilayer photoactive layer. A filter-free band-selective OPD model, comprising a bilayer shorter-wavelength light depletion layer/longer-wavelength light-absorbing layer architecture photoactive layer, has been developed. The depletion layer in the filter-free OPDs has a dual-function serving as a shorter-wavelength light-absorbing layer and a hole-transporting layer. The photodetection spectrum window of the filter-free band-selective OPDs, defined by the difference in wavelengths between the transmission cutoff of the shorter-wavelength light depletion layer and the absorption edge of the longer-wavelength light-absorbing layer, can then be tuned over the different wavelength ranges by using an appropriate combination of the shorter-wavelength light depletion layer and the longer-wavelength light-absorbing layer. A dual-mode OPD, having a trilayer visible light absorber/optical spacer/near-infrared (NIR) light absorber configuration photoactive layer, has been proposed. The dual-mode OPD exhibits electrically switchable NIR response operated under a reverse bias and visible light response operated under a forward bias. In the presence of NIR light, the trap-assisted charge-injection behavior at the organic/cathode interface in the OPDs operated under a reverse bias. The photocurrent is produced in the visible light-absorbing layer, enabled by the trap-assisted charge injection at the anode/organic interface under a forward bias. The developed filter-free band-selective OPDs and electrically switchable dual-mode OPDs provided an attractive alternative optical detection technology to the conventional panchromatic and single-mode OPDs. The spectral tunable photodetection thus demonstrated offers a promising option for new OPD applications.
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Xiang, Jing. "Electrofunctional ferrocene-containing metallopolymers for organic lithium-ion battery and organic resistive memory applications." HKBU Institutional Repository, 2016. https://repository.hkbu.edu.hk/etd_oa/286.
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This thesis is dedicated to developing three different types of ferrocene-containing polymers for organic lithium-ion battery and resistive memory applications. Chapter 1 gives an overview of organic cathode-active materials, polymeric resistive memories and ferrocene-containing polymers. Furthermore, the previously reported applications of ferrocene-containing polymeric systems in electrochemical energy storage and electronical memory devices were also comprehensively summarized. In chapter 2, conjugated ferrocene-containing side-chain metallopolymers PFcFE1, PFcFE2, PFcFE3 and PFcFE4 were designed and synthesized via Sonogashira cross-coupling polycondensation. The charging-discharging processes of triphenyamine-based PFcFE1 and thiophene-modified PFcFE4 have been successfully studied as cathode materials. PFcFE1 composite electrode showed a capacity of 90 mAh g-1 and the cathode composed of PFcFE4 retained over 90% of the initial capacity after 100 charging-discharging cycles at 10 C. These results demonstrate the great potentials of these ferrocene-containing side-chain polymers as active cathode materials for organic lithium-ion battery applicaitons. Besides, all prepared ferrocene-containing metallopolymers PFcFE1, PFcFE2, PFcFE3 and PFcFE4 also exhibited nonvolatile resistive switching behaviors with the flash memory effect of PFcFE1, PFcFE2 and PFcFE3 as well as the WORM memory feature of PFcFE4, indicating the easily tuned memory properties by changing the chemical structures of the active polymeric backbones. It is also worth noting that the ITO/PFcFE1/Al memory device showed a high ON/OFF current ratio of 103 to 104, a low switch-on voltage of -1.0 V, a long retention time of 1000 s and a large read cycle number up to 105, which is superior to other reported ferrocene-containing memory examples. Chapter 3 focuses on the development of non-conjugated ferrocene-containing copolymers PVFVM1, PVFVM1-1, PVFVM2, PVFVM3, PVFVM4, PVFVM5 and PVFVM6 based on different heteroaromatic moieties which were prepared by AIBN initiated chain addition polymerization. The as-prepared copolymers PVFVM1 and PVFVM1-1 exhibited electrochemical characteristics of both ferrocene and triphenylamine pendants with reversible multiple redox waves at the half potentials of E1/2 = --0.06, 0.30, and 0.42 V (vs. Fc/Fc+). Notably, the composite electrode based on PVFVM1 afforded a discharge capacity of 102 mAh g--1 at 10 C, corresponding to 98% of its theoretical capacity. The cycle endurances of the active polymer electrodes composed of PVFVM1 or PVFVM1-1 were both evaluated for over 50 numbers and no significant capacity reduction over cycles were observed. On the other hand, initial I-V results of memory devices based on PVFVM1, PVFVM1-1, PVFVM2, PVFVM3, PVFVM4 and PVFVM6 also revealed their huge potentials in electronic information storage. The stability and reproducibility of the corresponding memory devices based on these materials will be futher evaluated in the near future. We used 1,1'-ferrocenediboronic acid bis(pinacol) ester to develop conjugated ferrocene-containing main-chain metallopolymers in chapter 4. All these rational designed metallopolymers FcMMP1, FcMMP2, FcMMP3 and FcMMP4 with one or two ferrocene moieties were produced via Suzuki cross-coupling polycondensation. Their structural information, molecular masses, photophysical features and thermal properties have been well studied. Electrochemical performances of the formed polymers were also examined to clarify their potential as cathode-active materials. Other charge-storage characteristics and switching behaviors of these prepared ferrocene-containing main-chain metallopolymers for organic battery and memory applications are under further investigation.
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Barnabas, Ian Joseph. "Sample preparation in environmental organic analysis." Thesis, Northumbria University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245205.
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Dalby, O. J. "The analysis of organic ballistic materials." Thesis, Nottingham Trent University, 2011. http://irep.ntu.ac.uk/id/eprint/326/.
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Both gas chromatography/mass chromatography (GC/MS) and solid phase microextraction (SPME) methodologies have been developed for the extraction and analysis of compounds encountered in relation to unburned propellant powders from firearm ammunitions. These methods allowed the detection of 27 compounds that may be present in organic gunshot residues (OGSR). The developed methodologies were applied to the analysis of unburned propellant and OGSR from spent ammunition cartridges and fabrics subjected to firearm discharges. Throughout the study a total of 16 ammunition types where investigated. Work carried out on the suitability of various SPME fibre types showed that 65μm PDMS/DVB was the most appropriate type for extracting the compounds of interest. Extractions carried out on unburned propellant powders showed that all of the ammunitions analysed produced different chromatographic results. All of the ammunitions in the analysed population could be differentiated from one another; it was determined to be highly unlikely that false matches could occur. Extractions from spend cartridges showed that some of the compounds originating from the precursor propellants remained, with many compounds being lost during discharge. In some examples, however, all compounds in the unburned propellant were extracted from spent cartridges cases. The amount of variability of compound abundances between spent cases of the same ammunition types was shown to be much greater than the variability between unburned propellant samples. It was, therefore, concluded that firearms discharges are likely to be non-reproducible events, with varying amounts of non-combusted materials remaining in each case. These results were considered to have implications when carrying out ―time since discharge‖ back calculations on cases. The collection and extraction of shot fabric samples were carried out using Nylon evidence bags, traditionally used for the collection of fire/arson materials. Results from this work showed that for some ammunitions it was possible to link extracts from fabrics to spent cartridge cases and unburned propellant powders, by matching compounds present in the originator propellant to residue extracts. For other ammunition types it was shown to be possible to link fabric extracts to spent cases directly, by matching the compounds present in both.
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Wang, Yi. "Metal-organic and organic photosensitizers for photocatalytic hydrogen generation and carbon dioxide reduction." HKBU Institutional Repository, 2017. https://repository.hkbu.edu.hk/etd_oa/414.
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This thesis is focused on developing metal-organic and organic molecules for photocatalytic water splitting and carbon dioxide reduction. In chapter 1, an overview of hydrogen production, dye-sensitized solar cells and carbon dioxide reduction are provided. The development history and reaction mechanisms of catalytic systems are introduced along with the typical examples in each field. The applications of both metal-organic and organic compounds are covered. In chapter 2, nine molecular organic photosensitizers were designed and synthesized. The nine molecules were employed as the photosensitizing reagent in the fabrication of dye-sensitized solar cells and applied in photocatalytic water reduction via coupling with TiO2 semiconductors and Pt co-catalyst. The highest turnover number (TON) of 10200 was achieved by organic photosensitizer 1g for hydrogen generation. The effect of alkyl chains and triarylamine donor moiety to the photocatalytic performance was investigated. A shorter alkyl chain was found to favor the reaction due to a lower hydrophobicity which in turn may block the interaction between the photocatalyst and water molecules. Besides, the triarylamine donor units facilitated high hydrogen generation rates by reducing the contact between catalytic active sites and the oxidized form of sacrificial reagents. In chapter 3, five earth-abundant metal complexes were synthesized to serve as the catalyst and CdS nanorods (NRs) were prepared to be the photosensitizer for the photocatalytic water reduction. A cobalt dithiolene complex (2a) achieved a TON of 30635 in 20 h under the blue light irradiation at a concentration of 10 µM. A new complex 2c also gave a high TON of 12375 under the same conditions and its TON was further improved to 115213 in 87 h by reducing the concentration of catalyst by ten times. The size effect of CdS NRs was investigated and larger nanoparticles exhibited higher hydrogen production rates. In chapter 4, ten iridium(III) complexes were synthesized and used as dual-functional molecules in photocatalytic carbon dioxide reduction by acting as both the photosensitizing reagent as well as the catalyst. The best performance was achieved by 3j, giving a TON of 230 under the irradiation of blue LED. A push-pull effect brought by trifluoromethyl and methoxy group sucessfully enhanced the carbon dioxide reduction efficiency. The hydrophobicity of n-butyl chain also provided effective protection to the active sites of reaction intermediate. Additional steric hindrance was found to extend the lifespan of photocatalytic systems but led to a drop in the overall conversion efficiency. Chapter 5 summarizes the specific synthetic procedures and characterization parameters of the molecules in chapters 2-4.
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Di, Pietro Riccardo. "Charge accumulation spectroscopy of organic semiconductors." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610645.
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Baker, Eve A. "The Rhetoric of Organic Food Packaging." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1353339137.
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Peppe, Salvatore. "Some unusual, astronomically significant organic molecules." Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09php4241.pdf.
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Appendix inside back cover. "June 2002" Bibliography: leaves 157-168. Experimental and theoretical studies were carried out on a number of unusual organic molecules of potential astronomical significance. The experimental work was corroborated by various theoretical approaches and by utilising computer-based quantum chemical calculations. Various covalently bound, anionic and neutral oxocarbon species were formed and studied. Additionally, two analogous heterocumulenic systems were investigated. Some isomers of either system, when energised, were shown to undergo gas-phase rearrangement processes.
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Ganzarolli, Giovanna. "La ceramica comune dall’alto al basso medioevo in Veneto (Italia) : tipologie, commerci e analisi sui residui organici." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0363/document.
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Cette recherche doctorale porte sur l’analyse des « céramiques communes à pâte grossière » issues de 4 fouilles archéologiques de la Vénétie : celles de la cathédrale de Padoue, de Rocca de Monselice (Padoue), du château de Montagnone à Montegrotto Terme (Padoue) et de l’ancien cinéma Astra à Chioggia (Venise). Cette recherche se focalise plus particulièrement sur la « céramique commune à pâte grossière » employée pour l’usage culinaire à l’échelle de la Vénétie. Elle vise à mieux comprendre les changements de morphologies, de matières premières employées mais également de fonctionnalité entre le IVe et le XIV siècle apr. J.-C. Dans le cadre de ce travail, cette catégorie de céramique a été étudiée à travers une approche pluridisciplinaire associant, à la démarche d’archéologique et de typologique classique, des observations pétrographiques et des analyses chimiques de résidus organiques. La combinaison de ces expértises a permis d’observer :• une évolution typologique à l’échelle de la période chronologique investie pour la région de Padoue ces dernières ayant été confrontée avec des données déjà publiée pour la région de la Vénétie et des territoires limitrophes ;• des caractéristiques pétrographiques et un changement des « recettes » de pâtes employées dans la production de la céramique pour les usages culinaires ;• certains aspects fonctionnels des céramiques, notamment sur pour artefacts retrouvés lors de la fouille de la cathédrale de Padoue, permettant même de proposer des hypothèses sur les habitudes alimentaires ;• un lien entre l’évolution des « céramiques communes à pâte grossière » et les dynamiques économiques et politiques régionales<br>The aim of this research is the study of cooking wares, founded in 4 archaeological sites of Veneto region (North-eastern Italy): the archaeological excavation near the Padua cathedral, the archaeological excavation of Rocca di Monselice Castle (PD); the archeological sites of Montagnone of Montegrotto Terme castle; and the excavation in the ex-cinema Astra in Chioggia (VE). Therefore the object of this research is to observe over long time (from 4th to 14/15th century) the cooking wares of a small territory of Veneto region, the central-eastern part, to understand the evolutional change of morphologies, the origins of raw materials and the pottery function.The pottery was studied with the exploitation of different techniques and methodologies: the archaeological and typological approach; the petrographical analysis and the organic residue analysis. This method allowed the observation of:$\begin{itemize}\item the pottery morphological evolution, over long time in a small territory, taking into account also the published ceramic datas of Veneto and the nearest regions;\item the petrographical characteristic and the different use of ceramic paste over a log term for the cooking wares;\item for the archaeological site of Padua cathedral, the functional aspect of pottery. This aspect permits to speculate on the diet habits;\item the link between the cooking and coarse wares and the historical and economical aspects of Veneto. \end{itemize}$Finally this research gives a database to better understand the production characteristics of Paduan cooking wares
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Barlow, Guy F. "Analysis and design of organic semiconductor lasers." Thesis, Bangor University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340445.
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Evans, Evan Hywel. "Analysis of organic samples by plasma spectrometry." Thesis, University of Plymouth, 1989. http://hdl.handle.net/10026.1/1747.
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Deese, Steven Daniel. "Economic analysis weeding techniques for organic farmers /." Click here to view, 2010. http://digitalcommons.calpoly.edu/agbsp/14/.
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Thesis (B.S.)--California Polytechnic State University, 2010.<br>Project advisor: Wayne Howard. Title from PDF title page; viewed on Mar. 24, 2010. Includes bibliographical references. Also available on microfiche.
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CONCEICAO, CAMILA DA SILVA. "CRITICAL ANALYSIS OF PACKAGED ORGANIC FOOD LABELS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=22976@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO<br>O Brasil encontra-se entre os maiores produtores de orgânicos do mundo e o desenvolvimento do mercado de alimentos orgânicos está diretamente relacionado à confiança dos consumidores quanto à origem dos produtos. Nesse contexto, as informações dos rótulos e o selo de garantia de produto orgânico facilitam o consumidor identificar os alimentos que estão em conformidade com os regulamentos e normas técnicas vigentes e criam ambiente de confiança em circuitos longos de comercialização para os mercados desses produtos. Considerando a relevância do tema e a escassez de pesquisas de campo sobre rotulagem de alimentos orgânicos, o objetivo da dissertação é analisar a situação da conformidade de rótulos de alimentos orgânicos embalados e comercializados no município do Rio de Janeiro em relação à legislação aplicável, e propor recomendações para as entidades interessadas em uma melhor adequação da rotulagem desses produtos. A pesquisa de campo foi conduzida em 2012 e as amostras analisadas totalizaram 107 produtos, classificados segundo sete categorias, a saber: conservas e antepastos; confeitaria e chocolataria; bebidas; chás; laticínios; barras; e biscoitos e snacks. Os resultados quantitativos e qualitativos da conformidade (e da não-conformidade) da rotulagem das categorias selecionadas poderão ser utilizados por diversas entidades de interesse, como órgãos reguladores, órgãos de defesa do consumidor, organizações não-governamentais, fabricantes e seus fornecedores e consumidores de alimentos orgânicos embalados.<br>Brazil is among the largest producers of organic food and the development of organic food market is directly concerned to consumer confidence in relation to authenticity of the products. In this context, food labels and organic certification seals provide a wide range of valuable information to make healthier choices easier to consumers and also reliability in long circuits of organic food to market. Considering the importance of the topic and the lack of research with this focus, The objective of this dissertation is two-fold: (i) to analyze the state of compliance of packaged organic food labels commercialized in the city of Rio de Janeiro, focusing on the mandatory labeling information; and (ii) to propose recommendations for organizations interested in compliance of packaged organic food labeling to current Brazilian regulation concerning the selected food categories. The field research was conducted in 2012 and the samples analyzed totaled 107 products, classified into seven categories, as follows: canned and antepastos; confectionery and chocolates; beverages; teas; dairy products; biscuits and snacks; and cereal bars. The quantitative and qualitative results of compliance (and noncompliance) labeling of the selected categories can be used by several entities of interest such as regulators, consumer protection agencies, nongovernmental organizations, manufacturers and their suppliers and organic food consumers.
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Patriarca, Claudia. "Characterization of dissolved organic matter : An analytical challenge." Licentiate thesis, Uppsala universitet, Analytisk kemi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-341690.
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Dissolved organic matter (DOM) is the prevalent form of organic carbon in most aquatic environments. It is an ultra-complex mixture that plays a crucial role in global carbon cycling. Despite its importance it is still poorly understood due to its extreme heterogeneity and intricacy. Major advances in chemical characterization of DOM were possible with the introduction of high-resolution mass spectrometry (HRMS). This technique, in combination with direct infusion (DI) as sample introduction, is the most powerful tool for the DOM analysis to date. A compelling alternative to DI is represented by upfront separation with liquid chromatography (LC); however, current techniques involve only offline LC-HRMS approaches, which exhibit important logistical drawbacks, making DOM analysis more challenging. The aim of the presented studies was to develop new methods able to enhance the analysis of the dissolved organic matter and enable a wider range of researchers to participate in the advancement of this field. In the first study, the application of the Orbitrap mass spectrometer for resolving complex DOM mixtures was investigated and the results were compared to the more established state-of-the-art technique, Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The Orbitrap was capable of excellent reproducibility and detection of the majority of ionizable organic molecules in typical aquatic mixtures. The main disadvantage of the technique is that fewer molecular formulas can be resolved and detected because of lower resolution and sensitivity. This means that many sulfur peaks and all phosphorous containing peaks are not determined. Despite this drawback, our results suggest that the Orbitrap is an appropriate technique for the investigation of very subtle biogeochemical processing of bulk DOM. The lower costs (purchase and maintenance) and wider availability of Orbitrap mass spectrometers allow a greater number of laboratories to participate in the characterization of DOM. In the second study, the first online method involving reverse phase chromatography and ultrahigh resolution mass spectrometry for the analysis of DOM was developed. This method overcomes the disadvantages of typical offline approaches. It enhances enormously the amount of information achievable in a single run, maintaining high resolution data, reducing analysis time and potential contamination. The introduction of in silico fractionation makes the method extremely flexible, allowing an easy, fast, and detailed comparison of DOM samples from a variety of sources.
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Jolleys, Matthew. "A global analysis of biomass burning organic aerosol." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/a-global-analysis-of-biomass-burning-organic-aerosol(6dbebe3d-fb4a-4d68-b6c7-83c32ae3fa52).html.
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Organic aerosols represent one of the main sources of uncertainty affecting attempts to quantify anthropogenic climate change. The diverse physical and chemical properties of organic aerosols and the varied pathways involved in their formation and aging form the basis of this uncertainty, preventing extensive and accurate representation within regional and global scale models. This inability to constrain the radiative forcings produced by organic aerosols within the atmosphere consequently acts as a limitation to the wider objective of providing reliable projections of future climate. Biomass burning constitutes one of the main anthropogenic contributions to the global atmospheric organic aerosol (OA) burden, particularly in tropical regions where the potential for perturbations to the climate system is also enhanced due to higher average levels of solar irradiance. Emissions from biomass burning have been the subject of an intense research focus in recent years, involving a combination of field campaigns and laboratory studies. These experiments have aimed to improve the limited understanding of the processes involved in the evolution of biomass burning organic aerosol (BBOA) and contribute towards the development of more robust parameterisations for climate and chemical transport models. The main objective of this thesis was to use datasets acquired from several different global regions to perform a broad analysis of the BBOA fraction, with the extensive temporal and spatial scales provided by such measurements enabling investigation of a number of key uncertainties, including regional variability in emissions and the role of secondary organic aerosol (SOA) formation in aging smoke plumes. Measurements of BBOA mass concentration obtained using Aerodyne Research Inc. Aerosol Mass Spectrometers (AMS) were used to calculate characteristic ΔOA/ΔCO ratios for different environments, accounting for the effects of dilution and contrasting fire sizes to give a proportional representation of OA production. High levels of variability in average ΔOA/ΔCO were observed both between and within different regions. The scale of this variability consistently exceeded any differences between plumes of different ages, while a widespread absence of any sustained increase in ΔOA/ΔCO with aging indicates that SOA formation does not provide a net increase in OA mass. Despite this lack of OA enhancement, increasing proportions of oxygenated OA components in aged plumes highlight the chemical transformations occurring during the evolution of BBOA, and the additional influence of OA loss through evaporation or deposition. Potential drivers of variability in ΔOA/ΔCO at source, such as changes in fuel types and combustion conditions, were investigated for controlled fires carried out within a combustion chamber. These laboratory experiments revealed a number of complex relationships between BB emissions and source conditions. Although ΔOA/ΔCO was shown to be influenced by both fuel properties and transitions between flaming and smouldering combustion phases, the extent of these effects was limited, while variability between fires exceeded levels observed for ambient measurements. These findings emphasise the complexity of the BBOA lifecycle and the need to address the extensive uncertainties associated with its various constituent processes, in order to improve understanding of eventual climate impacts from biomass burning.
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Rhydderch, Shona. "Spectroscopic studies of photocatalysts for organic synthesis." Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=215112.
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Donahue, Marie Elizabeth. "Theory of Planned Behavior Analysis and Organic Food Consumption of American Consumers." ScholarWorks, 2017. https://scholarworks.waldenu.edu/dissertations/3558.
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The majority of organic foods consumed by Americans are sourced internationally, which has global-reaching implications on health, economics, and sustainability. Current research findings show that environmental devastation and negative health outcomes have resulted from unsustainable, nonorganic agricultural practices; including herbicides, pesticides, and overcultivation. However, there is a lack of quantitative research on factors that motivate Americans to consume organic food. Based on the theory of planned behavior, this quantitative study employed an online survey to examine the role of attitudes, subjective norms, descriptive norms, and perceived behavioral control on the intention and behavior of American consumers to consume organic foods. Additional descriptors of willingness to pay and perceived product attributes were also measured. Theory of planned behavior and American Organic Consumption questionnaires were completed by 276 adult consumers in the United States. Multiple regression analyses were performed to identify relationships and create predictive models between constructs of a modified theory of planned behavior, sociodemographics, and organic consumption. Key findings revealed that a modified theory of planned behavior, which included descriptive norms, predicted intent to consume organics stronger than the nonmodified theory of planned behavior. Attitudes, perceived behavioral control, and descriptive norms were significant predictors of intention to consume organics. Health was perceived as the major product attribute for organic consumption and low willingness to pay was perceived as the major barrier. This study has implications for positive social change such that it contributes to understanding motivational factors behind American's food choices and consumption, which can be used to modify and target consumer behaviors and market campaigns.
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Boyce, Geraldine. "Electron crystallography of organic pigments." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340747.
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Li, Yunchun. "Characterization of polar organic compounds and source analysis of fine organic aerosols in Hong Kong /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202008%20LIY.
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Combettes, Lorraine Eugenie Aurelie. "Synthesis and conformational analysis of fluorinated pyrrolidines." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:e0fa50a1-5f18-41d5-8cee-d0cb2e0a80de.
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The aim of this thesis was to investigate the synthesis and the conformational analysis of fluorinated pyrrolidines. We focused on two strategies namely, the iodoamination and fluoroamination of fluorinated precursors. Iodoamination Our first approach for the synthesis of fluorinated pyrrolidines relied on the iodocyclisation of allylic fluorides bearing pendant nitrogen nucleophiles. These allylic fluorides were obtained by fluorodesilylation of suitably functionalised allylsilanes. After validation of this methodology, the scope and limitations of the iodoamination were investigated. Furthermore, we were able to probe the influence of the fluorine moiety on the level of diastereocontrol of the cyclisation. Fluoroamination The second route focused on a key reaction: an unprecedented electrophilic fluoroamination of an aminated allylsilane. From a mechanistic point of view, the presence of the silyl group act as a 1,2-dipole and activate the double bond towards electrophilic fluorination. This methodology required the initial screening of a silyl directing group that would promote electrophilic addition, without subsequent desilylation. Finally, we investigated the level of diastereocontrol displayed by these cyclisations as a function of the E/Z geometry of the starting aminated allylsilane. Conformational analysis Moreover the 3-fluoropyrrolidines obtained via iodoamination served to investigate the stereoelectronic influence of the fluorine gauche effect on ring conformations. Solid state single crystal X-ray analysis and solution phase NMR spectroscopy were used for this purpose. Due to complicated conformational analysis of saturated five-membered rings in solution, 1D 19F-1H heteronuclear nOe (HOESY) experiments have been optimised for applications to this type of small molecules. These have been employed to estimate 19F-1H internuclear distances and were combined with vicinal 3JFH and 3JHH scalar coupling constants in order to analyse the ring conformations.
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Silwana, Nothemba. "Structure and thermal stability of selected organic inclusion compounds." Thesis, Cape Peninsula University of Technology, 2012. http://hdl.handle.net/20.500.11838/2618.
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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2012.<br>Crystal engineering is the synthesis of new crystalline materials with specific chemical and
physical properties which allows the comprehensive understanding of the non covalent
interactions that occur between molecules in the crystalline state. This has lead to extensive
work being done in terms of host design. The study of non-covalent interactions formed by -
these materials is crucial to understanding many biological processes.
This study focuses on the inclusion compounds of 1, 4-bis (diphenylhydroxymethyl) benzene
H, a host compound engineered by EWeber, that conforms to Weber's rules for host design
as it is bulky, rigid, and has hydroxyl moieties that act as hydrogen-bonding donors. A
Cambridge Structural Database (CSDversion 5.33) search has revealed that no research has
been conducted on this host compound. Characterization of the compounds were
conducted using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC),
hot stage microscopy (HS), gas chromatography (GC), powder X-ray diffraction(PXRD) and
single X -ray diffraction. Host: guest ratios determined from TG analysis were correlated
with structural analysis results.
We have successfully prepared inclusion compounds with N, N- dimethylformamide(DMF)
N, N- dimethylacetamide (DMA), N-methylformamide (NMF) and N-methylacetamide
(NMA), 2-picoline, 3-picoline, 4-picoline, pyridine and morpholine. Following which a series
of competition experiments were conducted to establish the selectivity profile of the host
by dissolving the host in an excess of two guests pairs, between DMF: DMA, DMF: NMF,
DMF: NMA, DMA: NMF, DMA: NMA and NMF: NMA. The results of the competition
experiment showed that the host had high selectivity for DMF and the selectivity profile
follows a trend as follows DMF>NMA>NMF>DMA. The results for the competition
experiments between the picolines, pyridine and morpholine were inconclusive.
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Ahmed, Taj Elsir Abbas. "New chemiluminescent reagents for organic and inorganic analysis." Thesis, University of Hull, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322554.
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Heron, Carol P. "The analysis of organic residues from archaelogical ceramics." Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254610.
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McCulloch, Corinne Sarah. "Compound specific isotope analysis of marine organic nitrogen." Thesis, University of Glasgow, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425164.
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Socorro, Gutiérrez Ingrid Maria. "Computational studies on the analysis of organic reactivity." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612832.
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Jackson, Catherine Mary. "Analysis and synthesis in nineteenth-century organic chemistry." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/10048633/.
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This dissertation examines the development of synthetic organic chemistry in academic laboratories in nineteenth-century Germany. By studying the laboratory practice of chemists including Justus Liebig, August Hofmann and Albert Ladenburg, I show that early synthetical experiments were undertaken with primarily analytical goals, and that construction did not become the dominant purpose of organic synthesis until around 1880. I argue that successful constructive synthesis depended on a new glassware based practice whose unprecedented scale and intrinsic danger drove the construction of purpose-built chemical laboratories from the 1860s onwards. I therefore propose both a revised historiography of nineteenth-century organic chemistry, and a reinterpretation of the institutional revolution in late-nineteenth century physical sciences. I re-examine Liebig's motives for tackling the analysis of alkaloids, using his 1830 laboratory notebook to reconstruct Liebig's experimental approach to this technically demanding task, including his development of a new apparatus for the determination of carbon — the Kaliapparat. I show that incorporating analysis using the Kaliapparat into a reliable, pedagogically stable method involved the labour of the entire Giessen research school. Liebig, his students and assistants produced new chemical knowledge from indeterminate analytical data by a combination of theoretical and practical expertise acquired through disciplined laboratory training, and I argue that a similar philosophy of practice was equally essential in synthetic organic chemistry. Synthesis made chemical identity a focus of chemists' practical concern and I demonstrate that purity, transformation and identity were central to Hofmann's constitutional analysis and Ladenburg's eventual synthesis of the hemlock alkaloid coniine. I explore the origins of what I term the glassware revolution, and its role in resolving the question of chemical identity. Finally, I show how Ladenburg's synthesis depended on glass and glassblowing, and I argue that this new chemical practice both produced and depended on highly organised, specialised laboratory spaces.
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Palmer, S. R. "The analysis of organic matter in oil-shales." Thesis, Aston University, 1987. http://publications.aston.ac.uk/9724/.
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The organic matter in five oil shales (three from the Kimmeridge Clay sequence, one from the Oxford Clay sequence and one from the Julia Creek deposits in Australia) has been isolated by acid demineralisation, separated into kerogens and bitumens by solvent extraction and then characterised in some detail by chromatographic, spectroscopic and degradative techniques. Kerogens cannot be characterised as easily as bitumens because of their insolubility, and hence before any detailed molecular information can be obtained from them they must be degraded into lower molecular weight, more soluble components. Unfortunately, the determination of kerogen structures has all too often involved degradations that were far too harsh and which lead to destruction of much of the structural information. For this reason a number of milder more selective degradative procedures have been tested and used to probe the structure of kerogens. These are: 1. Lithium aluminium hydride reduction. - This procedure is commonly used to remove pyrite from kerogens and it may also increase their solubility by reduction of labile functional groups. Although reduction of the kerogens was confirmed, increases in solubility were correlated with pyrite content and not kerogen reduction. 2. O-methylation in the presence of a phase transfer catalyst. - By the removal of hydrogen bond interactions via O-methylation, it was possiblo to determine the contribution of such secondary interactions to the insolubility of the kerogens. Problems were encountered with the use of the phase transfer catalyst. 3. Stepwise alkaline potassium permanganate oxidation. - Significant kerogen dissolution was achieved using this procedure but uncontrolled oxidation of initial oxidation products proved to be a problem. A comparison with the peroxytrifluoroacetic acid oxidation of these kerogens was made. 4. Peroxytrifluoroacetic acid oxidation. - This was used because it preferentially degrades aromatic rings whilst leaving any benzylic positions intact. Considerable conversion of the kerogens into soluble products was achieved with this procedure. At all stages of degradation the products were fully characterised where possible using a variety of techniques including elemental analysis, solution state 1 Hand 13C nuclear magnetic resonance, solid state 13C nuclear magnetic resonance, gelpermeation chromatography, gas chromatography-mass spElctroscopy, fourier transform infra-red spectroscopy and some ultra violet-visible spectroscopy.
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Guo, Jiu-Chun. "The development of simultaneous multi-analyte fluorescence immunoassays." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/32926.
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Fluorescence immunoassays have been established for a number of years as valuable methods of analysis in clinical chemistry and other fields, being sensitive, safe, easy to use and available in a variety formats. Those in common use are normally single analyte assays. But in many cases (e.g. forensic drug screening, therapeutic drug monitoring, screening for cancer markers, monitoring of thyroid function, or the analysis of environmental pollutants) dual- or multi-analyte assays would be much more valuable, with the advantages of increased information content, savings in time and costs, and the elimination of some sources of sampling variance. Amongst all the labels used in immunoassays, only fluorescent groups offer realistic prospects of practicable multi-analyte assays. This project has investigated single-, dual- and multi-analyte fluorescence immunoassays using several spectroscopic and software methods to resolve multicomponent fluorescence emission or synchronous spectra. The assays have been based on flow injection analysis methodology, with solid phase reactors to effect the separation of antibody-bound and unbound labelled analytes. The use of solid phase reactors incorporating thiophiIic gels to bind antibodies has also been investigated: these stationary phases have the advantage that bound antibodies can be eluted by changes of ionic strength, rather than changes of pH. This allows the use of a much wider range of fluorescence labels, clearly important in multi-analyte assays, and it has thus proved possible to develop successful dual and triple analyte assays, with results that compare well with other independent methods.
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Lee, Ka Man. "Multicolor organic light-emitting devices based on hydroxyquinoline complexes." HKBU Institutional Repository, 2001. http://repository.hkbu.edu.hk/etd_ra/336.
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Jackson, Stuart Thomas. "Surface analysis of polymer blends." Thesis, University of Sheffield, 1993. http://etheses.whiterose.ac.uk/14740/.
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Bentley, Zoe. "Chemical analysis of dietary supplements." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/843637/.
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The increased use of dietary supplements in today's society has been attributed to the general public's greater awareness of what constitutes a healthy diet. The elemental content (Ca, Cd, Cr, Co, Cu, Fe, Mg, Mn, Mo, Ni, Pb and Zn) of seventy-four dietary supplements (tablets, capsules and powders) was analysed by inductively coupled plasma mass spectrometry (ICP-MS). Different digestion methods (wet open vessel and microwave) were developed for the dissolution of dietary supplements, utilising both concentrated nitric acid and hydrogen peroxide. Both digestion procedures were found to give no significant statistical difference between the experimental results and certified values at a 99% confidence limit (Paired t-test) for all element values in two certified reference materials, namely NIES Rice Flour and IGGE Tea. For both certified reference materials, there was. The elemental content of the dietary supplements ranged from 0.1-200 mg/g for macro essential elements (Ca, Fe and Mg), 1-500 mug/g for trace essential elements (Cr, Co, Cu, Mn. Mo, Ni and Zn) and 0.4-10 mug/g for non-essential elements (Cd and Pb), all on a dry weight basis. Comparison of experimental results with commercial label values for dietary supplements showed: (1) calculated Ca and Mg concentrations were systematically lower than the label values; and (2) the experimental results for the other essential elements were in good agreement. The essential element contribution of base materials was investigated, though the results were inconclusive. Dietary supplements containing fat-soluble vitamins were analysed for retinol acetate, ergocalciferol (D2), cholecalciferol (D3), tocopherol (E), tocopherol acetate and phylloquinone (K1) using a modified simultaneous high performance liquid chromatography (HPLC) method. For each vitamin, a recovery of >90% was obtained with the use of a direct solvent extraction procedure. An in vitro study into the bioavailability of iron and zinc in yeast-based supplements was accomplished. This study provided results suggesting that iron supplements containing vitamin C were more bioavailable than yeast or tablet-based supplements that contained no vitamin C. Zinc bioavailability was observed to be greater in multi-component and yeast-based dietary supplements.
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Li, King Fai. "Ultra-fast spectroscopy investigation on organic molecules two photon absorption." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/911.
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Lundgren, Stina. "Efficient Synthesis and Analysis of Chiral Cyanohydrins." Doctoral thesis, Stockholm : Kungliga Tekniska högskolan (KTH), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4315.
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Nilsson, Eva. "Coupled Liquid Separation and Spectrometric Detection of Organic Compounds Containing Hetero-atoms." Doctoral thesis, Uppsala University, Analytical Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3977.
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<p>This thesis exemplifies the strength in the combination of inductively coupled plasma (ICP) spectrometry and electrospray ionization tandem mass spectrometry ESI-MS/MS as detection techniques for liquid chromatography (LC) in the search for and investigation of compounds that bind or can bind hetero-atoms. Furthermore, some aspects involved in the coupling of LC and ICP spectrometry and quantification without identical standards have been studied.</p><p>The importance of using a separation step in combination with ICP spectrometry was shown for urine and blood plasma samples from patients treated with boron neutron capture therapy. In addition to the carrier molecule used in the therapy, one major and a few possible minor metabolites were found in the urine samples. One fragment mass of the major metabolite was obtained with LC-ESI-MS/MS. Liquid chromatography coupled to ICP-MS was also shown to be a valuable tool for fingerprinting metal-binding compounds in complex matrices, such as siderophores (iron-complexing compounds) in soil. The presence of at least two siderophores in a field soil solution sample could be revealed by LC-ICP-MS. Their identities could thereafter be determined by LC-ESI-MS/MS. </p><p>The non-UV-absorbing <i>o</i>-carboranylalanine could be quantified in relation to its degradation products by LC-ICP-AES, which provided information about the mechanism behind the degradation. Moreover, LC-ICP spectrometry was shown to provide an accurate quantification of biomolecules (bias < 10 %) when evaluated from external calibration graphs based on inorganic elemental standards. </p><p>Finally, the causes of the large decrease in boron signal seen when adding acetonitrile to the LC mobile phase in LC-ICP-MS was investigated in some detail. Space charge effects might explain a large part of the depression from carbon species on the boron signal.</p>
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Tasker, Andrew David. "Femtosecond laser analysis of nitroaromatic molecules." Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250793.
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Madichie, Chinedu Arinze. "The chromatographic analysis of organic compounds in natural waters." Thesis, University of Hull, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310270.
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Somayaji, Chandramohan 1980. "First and second law analysis of Organic Rankine Cycle." Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-03102008-143144.
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Hodyss, Robert Blake Geoffrey A. "Methods for the analysis of organic chemistry on Titan /." Diss., Pasadena, Calif. : Caltech, 2006. http://resolver.caltech.edu/CaltechETD:etd-01122006-105657.
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Sylvestre, Olivier M. Eng Massachusetts Institute of Technology. "Organic waste management for EBI in Quebec, feedstock analysis." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90032.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2014.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 105-108).<br>EBI is a company located in the province of Quebec in Canada with the mission to integrate waste management. Great challenges in regards to organic waste management are faced and anaerobic digestion is considered by EBI as an innovative alternative to landfilling. The selection of the feedstock is a key success factor for an anaerobic digestion project. Based on an extended literature review, an investigation of organic waste available to EBI and a multi-criteria analysis, it is recommended to use a mix of food waste, dewatered septic systems sludge, poultry manure, wasted activated sludge, grease trap waste and liquid yeast as input for the anaerobic digester.<br>by Olivier Sylvestre.<br>M. Eng.
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D'Mello, Nigel. "Spectroscopic and thermal analysis of clay mineral-organic composites." Thesis, Sheffield Hallam University, 2003. http://shura.shu.ac.uk/19566/.
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Composites of clay minerals have been prepared with organic monomers for subsequent study upon polymerisation. Particular combinations of clays and organic species have enabled three unique systems to be studied. The first involves the intercalation of the clay minerals Kaolin and Halloysite with Phenylphosphonic Acid (PPA). The intercalation process proceeds via the use of an acetone/water entraining agent and subsequent analysis by Diffuse Reflectance Infrared Fourier transform Spectroscopy (DRIFTS), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Evolved Gas Analysis (EGA) using TG-Mass Spectrometry. This has revealed the remarkable thermal stability of these intercalates; they are stable to above 450 °C, and exhibit interlayer spacings of 15.4 A. Furthermore, the fate of the water as the entraining agent is determined and is found to be hydrogen bonded to the phosphonic acid moiety of PPA and also weakly bound to the inner surface hydroxyls in these clays. This water represents an opportunity for displacement by an organic monomer, and the lone pair of electrons on the oxygens also provide scope for coordination. Hence, the PPA intercalates were treated with the monomer N-vinylformamide (VFA) and evaluated for subsequent polymerisation. In the second system, montmorillonite was intercalated with VFA and then treated with a polar activator (Propylene Carbonate) prior to polymerisation. The polar activator interacts with the bifunctional VFA molecules causing the clay to swell further prior to polymerisation. This produces significant differences in the XRD traces with and without polymerisation of VFA in the presence of the clay. If the polar activator is absent the d[(001)] spacing is 21.0 A. If the polar activator is present then no d[(001)] is observed , in a situation reminiscent of an exfoliated nanocomposite. In the last system studied an in-situ intercalative approach was employed. Montmorillonite was treated with dialdehydes and diamines capable of reacting together to form amino resins oligomers and polymers. The molar ratio of the two reactants determines the intermediate and hence the subsequent product that is formed as characterised by DRIFTS. In a binary mixture where both reactants are simultaneously added to the clay, if the aldehyde is in excess, then dimethylol condensation products are formed. If the amine is in excess then monomethylol condensation products are formed. Sequentially adding these two reactants to clay (i.e. treating the clay first with one reactant and washing to remove any excess, then adding a second reactant) also has a bearing on the results. If the amine is added first, then the aldehyde is able to displace it from the clay interlayer. If however, the aldehyde is added first, then monomethylol reaction product is seen and this together with DRIFTS TGA and XRD analysis indicates that some of the aldehyde has been removed during the washing process.