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1
Massolo, E. „NOVEL SYNTHETIC ORGANOCATALYTIC METHODOLOGIES“. Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/330262.
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The objective of this PhD study was to apply organocatalytic synthetic methods for the regio- and stereoselective synthesis of highly functionalized compounds. We exploited different organocatalytic activation modes to peculiar substrates we identified as suitable building blocks for versatile products in enantiomerically enriched form. In particular the developed projects relied on stereoselective amino- and hydrogen bonding organocatalysis, employing beta-nitroacrylates, beta-trifluoromethylated nitroalkenes and 2,2,2-trifluoroethyl 2-[(1,3-dithian)-2-yl]-ethanthioate in combination with various reaction partners, thus finding entries to valuable intermediates suitable for further subsequent transformations.
The first Chapter of this thesis aim to give a general overview on those fields of organocatalysis related to the research topics studied in this PhD program, the second Chapter offers a literature background of the employed substrates. Following five Chapters (3-7) and Appendix report the discussion on the obtained results.
According to our opinion, this PhD study offers solid examples of robustness, versatility and effectiveness of stereoselective organocatalytic strategies, which have been applied to interesting starting materials and in innovative reaction media, thus giving a reliable contribution to expand the boundaries of this field.
2
Pujol-Santiago, Alba. „Development of novel catalytic asymmetric diborylation methodologies“. Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12161/.
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This thesis describes the study of the β-borylation reaction on different types of electron deficient substrates as well as the application of the methodologies herein developed into the synthesis of a key intermediate for cholesterol-lowering drug Atorvastatin. Within the frame of the use of organoboron compounds in organic synthesis, the literature review presented in the first section after a brief introduction on organoboranes is focused on the different strategies for their synthesis via boron addition, specially the β-borylation reaction. Different aspects of the reaction are covered; enantioselective version, the different methodologies reported for the activation of the diborane reagents or organic electron deficient substrates. Within the study of the β-borylation reaction on α,β-unsaturated aldehydes via the in situ generated amine-derived aldimine intermediates, and the further application of these synthetically attractive compounds, the relevant challenge of handling β-boryl aldehydes was met. It was confirmed that this type of compound was indeed unstable especially under chromatographic purification conditions, leading to de-borylation. In addition, mechanistic studies were carried out in order to achieve a better understanding of the whole process, but it was not possible to clarify it and avoid the undesired side-process. Hence, the establishment of an efficient derivatisation methodology was required. The solution consisted of a mild, efficient derivatisation process involving an in situ copper(II) sulfate-based imine hydrolysis followed by Wittig trapping of the resulting aldehyde. Further exploitation of homoallylic boronate carboxylate esters as substrates for a second borylation reaction, led to obtaining versatile 1,3-diborylated esters. A novel methodology was developed which allowed the control of the asymmetry induced in the new stereogenic centre created for a range of substrates, due to the presence of the two boryl units which could subsequently be transformed into other functionalities leading to building blocks for the synthesis of multi-functional, chiral compounds. Therefore, the two boryl units were then examined for transformation into functionalities which would allow unambiguous stereochemical assignment of the two borylation reactions. Specifically, an oxidation/acetal formation sequence was examined showing that 6-membered ring acetonide acetals were ideal compounds for this purpose. Beside aiding the stereochemical analysis, it was confirmed that this dual asymmetric borylation methodology was useful for the synthesis of 3,5-dihydroxy acids (or esters analogous) side-chain present in many natural products or drugs, such as statin-type drugs. Complementarily, and with the aim of expanding the type of substrates for the β-borylation reaction, structurally varied compounds were examined. Firstly, substrates presenting an additional unsaturation were evaluated under the imine formation/β-borylation reaction sequence conditions paying special attention to the 1,4- vs 1,6-addition selectivity, were examined as a possible alternative for the synthesis of diborylated compounds in a direct manner. This was followed by the study of different unsaturation, and in particular, an alkyne instead of an alkene, i.e. α,β-acetylenic carbonyl compounds, which were envisioned as ideal platforms for the synthesis of vinyl boronates. As well as a brief study on the β-borylation reaction on β-enamino ester substrates which could a priori give rise to valuable α-amino boronate compounds, is reported.
3
Lattimore, Brian Steven. „Novel methodologies for the analysis of microarray data“. Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.483566.
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4
Haji, Dheere Abdul Karim. „Novel [¹¹C]CO₂ radiolabelling methodologies for PET neuroimaging“. Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/novel-11cco2-radiolabelling-methodologies-for-pet-neuroimaging(a28f9e70-d697-4d69-afec-a8c3c34f1e93).html.
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PET is a non-invasive molecular imaging technique that is increasingly being used for medical imaging and drug development. Carbon-11 (11C; half-life 20.4 min) is one of the most commonly used radionuclides for PET molecular imaging. 11C is usually produced in the form of [11C]CO2 and converted into more reactive secondary precursors such as [11C]methyl iodide and [11C]carbon monoxide for radiolabelling. Although such secondary precursors are undoubtedly useful, given the short half-life of 11C, it would be advantageous to use [11C]CO2 directly from the cyclotron without additional time-consuming processing. Therefore, the development of radiochemical methods to efficiently radiolabel compounds directly with [11C]CO2 for applications in PET neuroimaging is an important goal and is the focus of this thesis. This work includes the development of novel radiolabelling methodology utilising [11C]CO2 for the radiolabelling of molecules based on urea and carbamate scaffolds. These functional groups are found in a plethora of biologically active molecules and pharmaceuticals. As proof of concept, the utility of the developed radiochemistry methods were applied to the synthesis of novel GABA and glutamate radiotracers. GABA and glutamate are major excitatory and inhibitory neurotransmitters in the brain. Although implicated in many diseases, the in vivo function of these neurotransmitter system is poorly understood. Their dysfunction are implicated in pathologies such as addiction, Alzheimer’s disease, Parkinson’s disease and autism. Monitoring the expression of the receptors in vivo and in vitro would enable better understanding of these diseases, their progression and treatment. The research described in this thesis unveils new methods to radiolabel novel molecules for these targets with 11C thereby enabling more opportunities to study them in vitro using autoradiography and in vivo using PET molecular imaging.
5
Saha, Bittu. „Development of Novel methodologies for the construction of c-hetero bond“. Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2823.
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6
Brun, Cubero Omar. „Novel methodologies for the conjugation and cyclisation of polyamides“. Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/399912.
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An alternative allowing diene-derivatised polyamides to be used in Diels-Alder conjugation reactions has been explored and developed. In this methodology, conjugation takes place between a fully protected, resin-linked diene-derivatised polyamide and a soluble maleimide- containing compound. The acid-labile diene is thus not exposed to acids, and the acidic deprotection treatment that follows does not affect the cycloadduct. In contrast with previously described alternatives, this methodology has no limitations in terms of sequence and does not require special protecting groups.
(E)-4,6-Heptadienoyl-polyamide-resins are used due to the good yields observed in the Diels- Alder reaction and the stability of the generated compounds. Polyamides are assembled using the standard, commercially available building blocks on water-swelling solid matrixes, and no special building blocks need to be synthesised. Both water and organic solvent/water mixtures can be used for the on-resin cycloaddition, and simultaneous maleimide deprotection and on- resin Diels-Alder cycloaddition is feasible, allowing conjugates with different linking sites to be prepared. The on-resin Diels-Alder reaction is also compatible with the wide-spread maleimide- thiol reaction, and combination of both transformations is feasible, making it possible to synthesise double conjugates. However, diene-derivatised oligonucleotides do not withstand the reaction conditions required for the solid-phase Diels-Alder conjugation, meaning that peptide- oligonucleotide conjugates cannot be prepared using this methodology.
In a different project, 2,2-disubstituted cyclopent-4-ene-1,3-diones (CPDs), which were chosen as non-hydrolysable maleimide analogs, have been found to possess an unexpected reactivity. While maleimides react in an irreversible manner with all types of thiols, the Michael-type reaction between CPDs and cysteines placed at internal or C-terminal positions, which do not possess a free amine, is reversible. In contrast, cysteines with a free amine (at the N-terminus of peptides) react with CPDs to end up furnishing a stable product with a mass 20 Da lower (M-
20 Da) than the Michael-type adduct (weighing M Da). Formation of the M-20 Da adduct plausibly takes place through the following steps: First, conjugate addition of the N-terminal cysteine thiol to the CPD double bond yields a Michael-type adduct. This product immediately undergoes intramolecular imine formation, by reaction between one of the CPD keto groups and the N-terminal amine, giving an intermediate with two fused rings and a mass 18 Da lower (M- 18 Da) than the initially formed Michael-type adduct. Subsequent oxidation of this M-18 Da adduct provides the final, stable M-20 Da adduct, which absorbs around 330 nm and whose structure has been confirmed by NMR.
This newly found reactivity can be applied for different purposes. Firstly, CPD-derivatised peptides can be used to synthesise conjugates by reaction with cysteine-derivatised PNAs. Secondly, the different reactivity of CPDs towards 1,2-aminothiols and other thiols has been exploited to selectively tag a peptide containing an N-terminal cysteine in the presence of peptides with cysteines in other positions, and to double-derivatise a peptide that contains an N- terminal and an internal cysteine. Use of CPDs with this last type of peptides also allows for their simultaneous cyclisation and derivatisation. Formation of the CPD-M-20 Da adduct is
followed by Michael-type addition of the internal thiol to this adduct, and finally by oxidation to yield a conjugated system absorbing around 370 nm. Cyclisation has been assessed by NMR experiments. The cyclisation reaction is accelerated by the presence of oxidants, namely O2 or TEMPO, and the addition of LiCl also has a beneficial effect, in particular with difficult to cyclise sequences. In this respect, it has been found that aromatic residues proximal to the N-terminal cysteine hinder the cyclisation.
The N-terminal cysteine of CPD-cyclised peptides undergoes epimerisation at the α carbon when exposed to bases, as confirmed by synthesis of the cyclic analogs from peptides with a D- cysteine at the N-terminus. Curiously, the latter are less prone to epimerise than the L-cysteine counterparts, for which reason use of the non-proteinogenic residue is recommended.En esta tesis se ha llevado a cabo el desarrollo de nuevas metodologías para la conjugación y ciclación de péptidos y otras poliamidas. En un primer proyecto, se buscó y encontró una alternativa que permitiera la conjugación de poliamidas derivatizadas con un 1,3-dieno generadas por síntesis en fase sólida, evitando la descomposición del dieno durante la desprotección final. Para ello se puso a punto una metodología que permitió conjugar, a través de una reacción de Diels-Alder, dichas poliamidas mientras se aún se encontraban protegidas y unidas a resina. Como dienófilos se usaron derivados de maleimida, debido a su fácil obtención, buena reactividad y su disponibilidad comercial. La reacción de Diels-Alder sobre resina se efectuó tanto en agua como en mezclas agua/disolvente orgánico, y es compatible con el uso de maleimidas protegidas y con la reacción de tipo Michael entre un tiol y una maleimida. En un proyecto distinto, se usaron ciclopent-4-en-1,3-dionas 2,2-disustituidas (CPDs) como análogos no hidrolizables de maleimida. Pronto se descubrió que su reactividad es muy distinta a la de las maleimidas, y que, mientras que su reacción con cisteínas internas o C-terminales es reversible, cuando reaccionan con cisteínas N-terminales se genera un producto estable. Éste tiene una masa 20 unidades menor (M-20 Da) que el producto de tipo Michael inicialmente esperado (M Da) un máximo de absorción alrededor de 330 nm. Esta distinta reactividad se ha usado tanto para la formación de conjugados como para la diferenciación de péptidos que poseen cisteína en la posición N-terminal frente a péptidos que la contienen en otras posiciones. Además, las CPDs también se pueden usar para conseguir la ciclación y derivatización simultánea de péptidos que contienen dos cisteínas, una de las cuales se encuentra en la posición N-terminal. En este caso se obtienen derivados cíclicos de masa M-22 Da con un máximo de absorción alrededor de 370 nm. Se recomienda el uso de D-cisteína en la posición N-terminal debido a su mayor estabilidad frente a la epimerización.
7
Anand, Sumit. „Novel applications of data mining methodologies to incident databases“. Texas A&M University, 2003. http://hdl.handle.net/1969.1/3998.
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Incident databases provide an excellent opportunity to study the repeated situations of incidents in the process industry. The databases give an insight into the situation which led to an incident, and if studied properly can help monitor the process, equipment and chemical involved more closely, and reduce the number of incidents in the future. This study examined a subset of incidents from National Response CenterÂs Incident database, focusing mainly on fixed facility incidents in Harris County, Texas from 1990 to 2002. Data mining has been used in the financial and marketing arena for many decades to analyze and find patterns in large amounts of data. Realizing the limited capabilities of
traditional methods of statistics, more robust techniques of data mining were applied to the subset of data and interesting patterns of chemical involved, equipment failed, component involved, etc. were found. Further, patterns obtained by data mining on the subset of data were used in modifying probabilities of failure of equipment and developing a decision support system.
8
Eymur, Serkan. „Development Of Novel Catalytic Methodologies For Carboncarbon Bond Construction“. Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615303/index.pdf.
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Addition reactions of nucleophilic trifluoromethyltrimethylsilane (CF3TMS) to acyl phosphonates were investigated. Various acyl phosphonates reacted readily with CF3TMS in the presence of K2CO3 to give 1-alkyl-2,2,2-trifluoro-1-trimethylsilyloxyethylphosphonate in 70-90% yields. When benzoyl phosphonates were used as starting material, after addition of CF3, the formed alcoholate undergoes phosphonatephosphate rearrangement to form the acyl anion, followed by elimination of F- to give 1-aryldifluoroethenyl phosphates in 87-97% yields.
The proline&ndashthiourea host&ndash
guest complex catalyzed intermolecular aldol reaction of aromatic aldehydes with cyclohexanone is developed. The anti-configured products were obtained in high yields and exclusively excellent nantioselectivities. The reaction is proposed to proceed according to a modified Houk&ndash
List model, in which the carboxylate moiety of the proline forms an assembly with the thiourea. These results clearly demonstrate the enormous effect of the thiourea on the reactivity and selectivity, even in an unconventional non-polar reaction medium, without the need to use low temperatures. A proline&ndash
thiourea host&ndash
guest complex is described as a good catalyst for the enantioselective nitro-Michael addition of aldehydes to nitroalkenes. The reaction is efficient with 5% of the thiourea, to give moderate to good enantioselectivity (up to 76% ee). High syn-selectivity was obtained with both branched and unbranched aliphatic aldehydes. This is the first example of self-assembly of organocatalysts with an achiral additive in a Michael addition wherein aldehydes are utilized as donors. An aldol reaction catalyzed by a proline&ndash
thiourea host&ndash
guest complex in a nonpolar solvent shows excellent nonlinear effects. This proline&ndash
thiourea system has the ability to form a hydrogen-bonding network. The enantiomeric excess of proline in a solution can be significantly enhanced by its incorporation with a urea molecule into its solid racemate. This suggests a general and facile route to homochirality, which may be involved in the origin of chirality on earth.
9
Oswald, Magalie Florence. „Novel synthetic methodologies for the synthesis of heterocyclic rings“. Thesis, University of Sussex, 2010. http://sro.sussex.ac.uk/id/eprint/2348/.
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Part 1. Synthesis of Stereodefined Heterocyclic Rings. We wish to report the development of novel methodology for the synthesis of stereodefined heterocyclic rings, which could be used for the synthesis of natural products containing for example tetrahydrofuran motifs, such as members of the pamamycin family. Due to their ambivalent properties, organoaluminium reagents can easily react with acetals by transfering an alkyl group after prior coordination with the substrates. This work has led to the development of a novel cascade reaction. It involves the reaction of acetals with trialkylaluminium reagents, which is followed by a cyclisation reaction, generating consequently tetrahydrofuran or tetrahydropyran rings. In addition, investigation towards the synthesis of pyrrolidines was also carried out. Part 2. Investigation and Development of a Novel Cascade Reaction. The Bergman cycloaromatisation reaction is based on the formation of a biradical intermediate species and has been, over the years, a constant source of inspiration for scientists. Continued efforts over the last 40 years permitted, among other things, a better understanding of the mode of action of the enediyne antibiotics, a class of natural compounds with exceptional biological activities. The Parsons group recently developed a novel cyclisation reaction, which also generates a biradical species, and which could, after being trapped with a suitable alkene, lead to the formation of tricyclic molecules containing heterocyclic cores. As a result, we wish to further investigate this novel reaction and develop a tandem reaction, involving this reaction combined with a Diels-Alder reaction in order to generate pentacyclic molecules, in one synthetic operation, and from an acyclic precursor.
10
Bourne, Samuel. „Development of novel gas-flow methodologies for pharmaceutical synthesis“. Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708895.
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11
Brock, Joseph William. „Novel methodologies for developing medical and scientific animated narrative“. Thesis, Goldsmiths College (University of London), 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523117.
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12
Blake, Emma. „Novel methodologies to enhance the effectiveness of clinical photodynamic therapy“. Thesis, Exeter and Plymouth Peninsula Medical School, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556512.
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Protoporphyrin IX (PpIX)-induced photodynamic therapy (POT) utilises the combined interaction of the photosensitiser PpIX, light of a specific wavelength and molecular oxygen to produce cytotoxic species which ultimately leads to the ablation of tumour cells. Dermatological PpIX-PDT, although established for superficial lesions, would be a more attractive treatment modality if its efficacy for the removal of thicker cancerous and precancerous skin lesions could be improved. Additionally, an excessive accumulation of naturally fluorescent PplX can be clinically useful for photodiagnosis (PO) or fluorescence guided resection (FGR) as adjuvant aids in the surgical resection of primary brain tumours. The aims of this thesis were therefore to i) increase and/or accelerate PplX photosensitiser accumulation and thus POT efficacy following irradiation and to ii) investigate the effects of oxygen manipulation on the POT process. In vitro experimentation demonstrated that 5-aminolaevulinic acid (ALA) and its ester methyl aminolevulinate (MAL) coincubated with the iron chelator CP94, significantly enhanced levels of PplX fluorescence in U-87 MG human glioma cells. Following irradiation the greatest cytotoxicity was observed when each congener was coincubated with CP94. Further investigation compared dexrazoxane, an already approved drug used clinically known for its iron chelating properties, with CP94. ALA, MAL and in addition hexyl aminolevulinate (HAL) coincubated with iron chelation, significantly enhanced and accelerated PplX fluorescence in both A431 squamous epithelial carcinoma cells and U-87 MG human glioma cells. Employing CP94 to increase and/or accelerate MAL-induced Pp IX accumulation in nodular basal cell carcinomas (nBCC) was investigated clinically. The results suggest that the clinical utilisation of CP94 may offer a simple modification to potentially increase the efficacy of MAL-POT by temporarily increasing PplX accumulation. Furthermore, in vitro manipulation of the oxygen environment was found to affect PplX fluorescence levels pre- and post-irradiation and thus subsequent cell viability. Oxygen manipulation requires further investigation but employment of an oxygen pressure injection (OPI) device during dermatological MAL-PDT was not found to be an effective method to improve tissue oxygenation during irradiation. However, the positive effects of employing an OPI device to drive MAL cream deeper into nBCC on cream application were confirmed. It is therefore clear that much can be done to further improve PDT treatment protocols for different clinical applications and one of the most straight forward methods of enhancement that can be employed is the concurrent application of the iron chelating agent, CP94.
13
Lee, May May. „Development of novel analytical methodologies based on biomolecular conformational changes“. Thesis, University of East Anglia, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273569.
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14
Dodd, Fiona. „Technologies and novel methodologies for the assessment of nutritional interventions“. Thesis, Northumbria University, 2016. http://nrl.northumbria.ac.uk/32312/.
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The aim of this thesis was to identify novel techniques in the assessment of nutritional intervention effects upon cognition. The impact of combining different cognitive and physiological assessments of nutritional interventions was explored in order to establish whether it could provide a more detailed picture of any effects, as well as the mechanisms by which they may occur. This thesis initially used two different technologies, electroencephalography (EEG) and near infrared spectroscopy (NIRS) to assess the cerebro-electrical and haemodynamic impact of cognitive task performance following Ginkgo biloba and a Ginkgo biloba/Panax ginseng combination, in healthy young adults. Following on from this, the effects of two different doses of Ginkgo biloba were investigated on cerebral blood flow and oxygenation parameters during the repeated administration of cognitively demanding tasks. The synergistic effect of two interventions believed to possess disparate effects on cerebral blood flow; caffeine and L-theanine, were then assessed during the performance of a range of cognitive tasks. To evaluate the peripheral as well as the central impact of task performance, a further assessment of (two doses) caffeine was conducted whilst cerebral blood flow and oxygenation parameters were monitored alongside an assessment of metabolism via indirect calorimetry (ICa). In an extension of the methodology, an exercise element was incorporated into the protocol and beetroot juice was administered whilst cerebral blood flow and haemodynamics were monitored during task performance, before, during and after cycling at different exercise intensities. The results of this thesis have identified that the methodologies adopted are capable of detecting changes in cerebral oxygenation as a result of, nutritional challenge; differing doses of the same intervention; the synergistic effect of two different interventions, and during incremental exercise whilst performing cognitive tasks. The concomitant measurement of NIRS and ICa were also shown to be effective in simultaneously determining the somatic and cognitive demands of a task. These findings demonstrate the positive contribution to research of combining technologies and methodologies in the assessment of nutritional interventions and provide valuable information in respect of their use in cognitive research.
15
Ahmad, Ghulam. „Novel design and measurement methodologies of millimeter wave smart antennas“. Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/848759/.
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Next generation wireless communication systems are expected to support unprecedented extremely high data transfer rates. This objective requires wider bandwidths which are presently only available at the millimeter waves (mm-waves) spectrum (30-300 GHz). Due to stringent propagation impairments, mm-waves mainly rely on the line of sight communication links which require high gain and wide angle beamsteeering smart antennas to maintain their performance. Owing to the complexity and losses in array beamformers, the realization of a high gain wide angle electronic beamsteering antenna solution at mm-waves becomes a key challenge. This research provides a potentially competing novel high gain electronic beamsteering antenna solution for mm-waves in the form of a phase quantized smart reflectarray consisting of high performance reconfigurable unit cells. Novel contributions of this research are: (a) Analysis of mm-wave reflectarray unit cells including the effects of fringing fields, surface waves, finite metal conductivity and metal surface roughness. (b) New measurement techniques for mm-wave reflectarray unit cells to ease the alignment, orientation, and DC biasing issues. (c) Characterization of PIN diodes at 10 GHz and 60 GHz for their ON/OFF state models extraction from measurements. (d) Design of three state implicit phase shifter reflectarray unit cell at 60 GHz, reduction in its DC bias lines, and an optimization technique to improve polarization purity of a multi-state reconfigurable unit cell. (e) A fast algorithm to prepare the electromagnetic simulation model of large reflectarrays. (f) Conception and measurement based validation of phase quantized reflecarrays and their performance matrix. (g) Conception and measurement based analytical solution of low DC power consuming smart reflectarrays. The resulting solution is agile, simple to implement, do not necessarily require multiple RF chains, enables wide angle electronic beamsteering (+-78 degree), is scalable for any gain/frequency requirements, can be made foldable for smaller satellite platforms, is very reliable, and consumes low DC power. This smart reflectarray platform can implement any phase only synthesis technique for radiation pattern control including single/multiple pencil beams, contoured beams, and their scanning over wider angles. Findings of this research would potentially benefit next generation terrestrial/air/space communication systems and radars.
16
Farenzena, Marcelo. „Novel methodologies for assessment and diagnostics in control loop management“. reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/13943.
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Na literatura há vários trabalhos elucidando a importância de ferramentas para auditar malhas de controle. Na indústria, o interesse por esse tipo de software é crescente, devido ao benefício trazido: garantir o exato desempenho para cada controlador significa atingir pontos de operação mais lucrativos. Todavia, as metodologias disponíveis na literatura e nas ferramentas comerciais não provêm medidas conclusivas das características da malha. Conseqüentemente, a análise muitas vezes é confusa e difícil, acarretando um diagnóstico difícil. Reduzir a distância entre a auditoria e o diagnóstico, propondo novas métricas para ajudar o engenheiro no gerenciamento de malhas é o foco central deste trabalho. A presente tese é segmentada em duas partes: auditoria e diagnóstico, dentro das quais se inserem as principais contribuições deste trabalho. A primeira contribuição deste trabalho é a proposição de uma metodologia para decompor o impacto da velocidade do controlador, tempo morto e ruído branco sobre a variância total da malha, auxiliando o engenheiro de processos a tomar uma ação: trocar os parâmetros de ajuste, aumentar a ordem do controlador, substituir o medidor, reduzir o tempo morto, entre outros. O método proposto requer apenas dados de operação normal e o tempo morto da malha, não sendo necessários testes intrusivos, sendo possível a aplicação industrial. O conjunto de métricas propostas foi aplicado em três casos de estudo, fornecendo resultados promissores. Dentro do campo de auditoria, se insere a segunda contribuição: a proposição de uma metodologia para estimação de parâmetros conclusivos (ou determinísticos) para avaliação da performance e robustez de controladores (Máxima Sensibilidade, razão entre o tempo de subida de malha aberta e fechada, razão entre o tempo de assentamento de malha aberta e fechada, entre outros), baseado em índices estocásticos (i.e. métricas que podem ser computadas em tempo real, sem testes intrusivos) e parâmetros da malha (tempo morto, constante de tempo). O modelo de inferência para desempenho e robustez, chamado PRIM, é proposto. Este modelo fornece uma clara indicação do real desempenho e robustez da malha, facilitando a análise e tornando o diagnóstico direto. Além disso, visando elucidar a vantagem dos índices determinísticos sobre os estocásticos, ambos serão aplicados a um conjunto de casos de estudo. A última contribuição no campo de auditoria está na estimação do potencial impacto econômico de cada malha, como ferramenta para hierarquizar sua manutenção. Considerando que uma típica planta química possui centenas ou milhares de malhas e que a maioria delas possui significativo potencial de melhora, a priorização da manutenção é essencial. O impacto econômico é baseado no conceito de Matriz de Variabilidade (VM), que é uma matriz que mostra o impacto da melhora da performance de um controlador sobre a variabilidade de toda a planta. A segunda parte deste trabalho aborda o diagnóstico de algumas avarias comuns em controladores. A primeira metodologia visa quantificar a banda de agarramento em válvulas de controle, que apresentam este fenômeno, através de um modelo de inferência chamado SIM. A metodologia proposta requer apenas dados de operação normal do controlador e planta. A contribuição final deste trabalho é um método simples para avaliação do modelo em controladores preditivos MPCs, baseado na Análise de Componentes Independentes (ICA). Esta análise é bastante útil para indicar os canais que possuem modelo pobre em relação à planta. O trabalho finaliza com as conclusões finais e os trabalhos futuros relativos a esta tese.Many works available in the literature support the importance of control loop performance assessment (CLPA) tools. Industrially, there is an increasing interest in this area and the reason is trivial: ensuring the exact performance for each loop means allowing it to operate in a high profitable operating point. However, the available methodologies in commercial tools and literature do not provide clear and conclusive metrics of the actual loop performance. Consequently, the diagnostics is not easy, making the analysis sometimes difficult and confusing. The aim of this thesis is to reduce the gap between assessment and diagnostics by proposing a set of metrics to help the engineer in control loop performance management. The thesis is divided into two sections: Assessment and Diagnostic. The first contribution of this work is the proposition of a new methodology to decompose the impact of control loop performance, time delay, and white noise in the total control loop variance, helping the engineer to diagnose the loop performance problem and take the right action to achieve the desired product variability (by changing tuning parameters, changing controller type, replacing instrument, or changing the process, among others). The proposed method does not require any invasive tests, only control loop routine operating data and process time delay, allowing the industrial application of the proposed indices in real time. The methodology was applied in three case studies, providing very good results. The second contribution is propose a methodology to estimate conclusive indices (also called deterministic indices) to evaluate loop performance and robustness (maximal sensitivity, ratio between open and closed loop rise time, settling time, among others), based on stochastic indices (i.e. indices that can be computed using only normal operating data) and process parameters (time delay and time constant). A performance and robustness inferential model (PRIM) for loop assessment will be shown. The PRIM provides a clear picture of loop performance and robustness, making the analysis easier and the diagnostics straightforward. Moreover, this section highlights the limitation and drawbacks of stochastic metrics for CLPA. The last contribution of the Assessment section proposes a method to prioritize loop maintenance, based on the economic impact of each loop. Assuming that a typical process plant has hundreds or thousands of loops and most of them have significant impact over loop variability, prioritizing loop maintenance is essential. The economic impact is based on the concept of Variability Matrix (VM), which is an array that shows the impact of performance improvement of a given loop on the whole plant. The second section of this work is the Diagnostics of some controller problems. The first methodology aims to quantify the stickband in a sticky valve, using only normal operating data of controller output and process variable. An analogous inference model, called Stiction Inference Model (SIM), is proposed to estimate the stickband. In the final contribution, it is proposed a simple method to evaluate the Model Plant Mismatch (MPM) based on Independent Component Analysis (ICA). This analysis is very useful to point out the poor channels models in Model Predictive Controllers. The work ends with concluding remarks and further work.
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Meneghini, Fabio. „Multimodal functional neuroimaging: new insights from novel head modeling methodologies“. Doctoral thesis, Università degli studi di Trieste, 2011. http://hdl.handle.net/10077/4522.
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2009/2010Neuroimaging plays a critically important role in neuroscience research and management of neurological and mental disorders. Modern neuroimaging techniques rely on various “source” signals that change across different spatial and temporal scales in accompany with neuronal activity. Nowadays, several types of noninvasive neuroimaging modalities are available based on biophysical signals related to either brain electrophysiology or hemodynamics/metabolism. In this dissertation, advanced model-based neuroimaging methods for the estimation of cortical brain activity from combined high-resolution electroencephalography (EEG), multimodal Magnetic Resonance Imaging (MRI) and functional Magnetic Resonance Imaging (fMRI) data are presented. The present dissertation begins with a review of the current state-of-the-art in the major neuroimaging techniques. Particular attention has been devoted to EEG modelling since such signals propagate (virtually) instantaneously from the activated neuronal tissues via volume conduction to the recording sites on/above the scalp surface. The instantaneous nature of EEG indicates an intrinsically high temporal resolution and precision, which make it well suited for studying brain functions on the neuronal time scale. The collective nature suggests low spatial resolution and specificity, which impede mapping brain functions in great regional details. However, this is regardless of recent advancements in electromagnetic source imaging, which has led to great strides in improving the EEG/MEG spatial resolution to a centimetre scale or even smaller. These methods entail: 1) modeling the brain electrical activity; 2) modeling the head volume conduction process so as to link the modeled electrical activity to EEG; and 3) reconstructing the brain electrical activity from recorded EEG data. For this aim, a subject's multicompartment head model (scalp, skull, CSF, brain cortex, white matter) is constructed from either individual magnetic resonance images or approximated geometry models. We compared different spherical and realistic head modelling techniques in estimating EEG forward solutions from current dipole sources distributed on a standard cortical space reconstructed from Montreal Neurological Institute (MNI) MRI data. Computer simulations are presented for three different four-shell head models, two with realistic geometry, either surface-based (BEM) or volume-based (FDM), and the corresponding sensor-fitted spherical-shaped model. Point Spread Function (PSF) and Lead Field (LF) cross-correlation analyses were performed for 26 symmetric dipole sources to quantitatively assess models’ accuracy in EEG source reconstruction. Both statistical and imaging analysis point to the realistic geometry as a relevant factor of improvement, particularly important when considering sources placed in the temporal or in the occipital cortex. In these situations, using a realistic head model will allow a better spatial discrimination of neural sources when compared to the spherical model. Moreover a brief overview of Diffusion Weighted Imaging and Diffusion Tensor Imaging is also given, as their application in modelling refinement is increasing the accuracy and the complexity of the brain models. Both fMRI and EEG represent brain activity in terms of a reliable anatomical localization and a detailed temporal evolution of neural signals. Simultaneous EEG-fMRI recordings offer the possibility to greatly enrich the significance and the interpretation of the single modality results because the same neural processes are observed from the same brain at the same time. Nonetheless, the different physical nature of the measured signals by the two techniques renders the coupling not always straightforward, especially in cognitive experiments where spatially localized and distributed effects coexist and evolve temporally at different temporal scales. The purpose of the last chapter is to illustrate the combination of simultaneously recorded EEG and fMRI signals exploiting the principles of EEG distributed source modelling. We define a common source space for fMRI and EEG signal projection and novel framework for the spatial and temporal comparative analysis. We use simultaneous EEG-fMRI in order to explore the relationship between the envelope of spontaneous neuronal oscillations in the alpha frequency band (8-13 Hz) recorded with EEG during eyes closed rest and spontaneous fluctuations of the fMRI BOLD signal. We showed on a single-subject analysis how the presented approach, when combined to an accurate realistic head modelling, is able to localize the alpha rhythmic modulation in the occipital visual area and the parieto-occipital sulcus. This finding is in line with recent studies, asserting that, within these regions, time-frequency analysis and phase-synchronization analysis indicated increased alpha power and alpha-band phase-synchronization in eyes-closed condition versus eyes-open condition. Given the lack in the scientific literature of group-analysis experimental studies performed with realistic modelling approach in this field, this topic will be further investigated in future work.
XXII Ciclo
1980
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Tinarelli, Alessandro <1975>. „Novel Methodologies for the Synthesis of Scaffolds for Bioactive Molecules“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2291/1/Tinarelli-Alessandro-tesi.pdf.
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Tinarelli, Alessandro <1975>. „Novel Methodologies for the Synthesis of Scaffolds for Bioactive Molecules“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2291/.
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Genoni, A. „EXPLORING NOVEL ORGANOCATALYTIC METHODOLOGIES FOR CARBON-NITROGEN DOUBLE BOND REDUCTION“. Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/229551.
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The development of novel methodologies for the preparation of enantiomerically pure compounds is a topic of great interest for several fields. In particular, it must be mentioned that chiral amines are finding applications in an ever-increasing number of fields, so the possibility of developing an organocatalytic approach has gained much attention.
During my work, the enantioselective organocatalytic reduction of fluorinated ketimines was successfully realized by using trichlorosilane as reducing agent in the presence of catalytic amounts of an inexpensive and readily available picolinamide derived from ephedrine. The methodology allowed to reduce imines derived both from aryl and alkyl trifluoromethyl ketones in very good yields and high enantioselectivities, typically of 90% e.e. and up to 98% e.e.. With a ACE (Asymmetric Catalyst Efficiency) value of about 44, the ephedrine-derived picolinamidic catalyst established itself as one of the most efficient and versatile catalyst for the reduction of a wide range of fluorinated imines, favourably comparing both with chiral phosphoric acids and even with organometallic catalysts. The well documented possibility to easily remove the N-PMP residue or the benzyl group makes the present method a viable and attractive synthesis also for highly enantiomerically enriched fluorinated primary amines.
Moreover, the straight forward synthesis of a novel class of cinchona-based chiral Lewis bases was developed. A series of enantiomerically pure Lewis bases were obtained by performing a Mitsunobu reaction on the commercially available alkaloids followed by simple condensation with picolinic acid. Under the optimized reaction conditions, such compounds were shown to promote the enantioselective reduction of ketimines with trichlorosilane with nearly quantitative chemical yield and high enantioselectivity. Even more interestingly, these high levels of yields and enantioselectivity remained constant when the reaction was carried out with only a 1 mol % catalyst loading. Further modification of these compounds allowed to raise the enantioselectivity of the process, leading to the quantitative formation of the corresponding amine with up to 88% e.e..
These catalyst were successfully employed also in the organocatalytic reduction of alpha-imino and beta-enamino esters with trichlorosilane, obtaining the corresponding products with high chemical yield and good enantiomeric excess. Moreover, the combination of this low cost, easy to make metal-free catalyst and an inexpensive chiral auxiliary allowed to obtain chiral beta-amino esters with nearly total control of the stereoselectivity.
In the field of catalytic methods for carbon nitrogen double bond reduction, I’ve also studied a very novel catalytic approach to realize the activation and utilization of H2: the concept of frustrated Lewis pair (FLP) recently introduced by the Stephan’s research group. Once performed a screening of several additives to find an efficient catalytic pair, the FLP catalyzed diastereoselective hydrogenation of a chiral ketimine was accomplished with 67% yield and 82:18 d.r. without the necessity to perform the reaction in glovebox.
Finally, taking into account the excellent enantioselectivities obtained in the reduction of C-N double-bonds with phosphoric acid catalysis, we decided to explore the performance of these systems employing HSiCl3 as reducing agent. After an optimization of the stoichiometry of the reaction, we were able to achieve up to 29% e.e. using 10 mol % unsubstituted BINOL-derived phosphoric acid, which could be raised up to 60% e.e. using a stoichiometric amount of the acid.
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Dasgupta, Hridoydip Ranjan. „Studies on novel methodologies for the synthesis of precursor of bioactive compounds“. Thesis, University of North Bengal, 2021. http://ir.nbu.ac.in/handle/123456789/4341.
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Subasi, Nuriye Tuna. „Novel Synthetic Methodologies For Heeocycles As Building Blocks In Drug Synthesis“. Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613028/index.pdf.
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Nitrogen containing heterocycles have always constituted a subject of great interest due to their wide presence in biologically important compounds so the development of efficient methods for the preparation of pyrrole derivatives and formation of new pyrrole-based heterocyclic compounds are an attractive goal in heterocyclic chemistry. In this study, starting from dimethoxytetrahydrofurane and amino acid esters, unsubstituted pyrrole derivatives, and treatment of amino acid esters with convenient chloroenones 1,2-disubstituted and 1,2,4-trisubstituted pyrrole derivatives were synthesized without racemization. Reaction of unsubstituted pyrrole derivatives with norephedrine toward inter- and intramolecular cyclizations give new interesting heteropolycylic compounds with oxazole-pyrrole-pyrazine structures. Study continued with cyclization reaction of these synthesized substituted and unsubstituted pyrrole derivatives with BBr3 and new bicyclic pyrrole derivatives were obtained in moderate yield.
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Sethuraman, Balasubramanian. „Novel Methodologies for Efficient Networks-on-Chip Implementation on Reconfigurable Devices“. Cincinnati, Ohio : University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?ucin1196043683.
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Thesis (Ph. D.)--University of Cincinnati, 2007.Advisor: Ranga Vemuri. Title from electronic thesis title page (viewed Feb. 18, 2008). Keywords: Networks-on-Chip (NoC), System-on-Chip (SoC), FPGA, Reconfigurable & Platform-Based Design, Light Weight Router Design, Multi Local Port Router, Multicast Router, Low Power Topology Generation & Mapping, Power Issues and IR drop Analysis, Minimum. Includes abstract. Includes bibliographical references.
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Wright, David T. „Novel analysis and modelling methodologies applied to pultrusion and other processes“. Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/7151.
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Often a manufacturing process may be a bottleneck or critical to a business. This thesis focuses on the analysis and modelling of such processest, to both better understand them, and to support the enhancement of quality or output capability of the process. The main thrusts of this thesis therefore are: To model inter-process physics, inter-relationships, and complex processes in a manner that enables re-exploitation, re-interpretation and reuse of this knowledge and generic elements e.g. using Object Oriented (00) & Qualitative Modelling (QM) techniques. This involves the development of superior process models to capture process complexity and reuse any generic elements; To demonstrate advanced modelling and simulation techniques (e.g. Artificial Neural Networks(ANN), Rule-Based-Systems (RBS), and statistical modelling) on a number of complex manufacturing case studies; To gain a better understanding of the physics and process inter-relationships exhibited in a number of complex manufacturing processes (e.g. pultrusion, bioprocess, and logistics) using analysis and modelling. To these ends, both a novel Object Oriented Qualitative (Problem) Analysis (OOQA) methodology, and a novel Artificial Neural Network Process Modelling (ANNPM) methodology were developed and applied to a number of complex manufacturing case studies- thermoset and thermoplastic pultrusion, bioprocess reactor, and a logistics supply chain. It has been shown that these methodologies and the models developed support capture of complex process inter-relationships, enable reuse of generic elements, support effective variable selection for ANN models, and perform well as a predictor of process properties. In particular the ANN pultrusion models, using laboratory data from IKV, Aachen and Pera, Melton Mowbray, predicted product properties very well.
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Duggan, Matthew P. „Miniaturisation of novel analytical detection methodologies : towards nanosensor arrays for bioanalysis“. Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436863.
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Chalk, Christopher David. „Novel IC test methodologies : evaluation of AC RMS supply current monitoring“. Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244997.
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Nair, Vasu. „Methodologies for the synthesis of novel modified nucleosides with therapeutic potential“. Title page, contents and abstract only, 1990. http://hdl.handle.net/2440/38539.
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Lobo, Ruiz Ariadna. „Pushing peptides further: Novel methodologies for the synthesis of backbone-modified peptides“. Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/667017.
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Peptides and proteins are essential substances for living organisms, as they can be found in every cell and tissue and are involved in many biological and physiological processes. Given their intrinsic properties and their attractive pharmacological profile, they have emerged as potential tools for drug discovery. However, in vivo instability due to protease degradation and poor bioavailability are the main drawbacks that have hampered their exploitation as therapeutic agents. Of special interest are peptide-based molecules displaying peptide backbone modifications, since they often result in improved pharmacological properties, such as greater stability and bioavailability, enhanced cell permeability and lower toxicity. Among the most relevant types of bioactive backbone-modified peptide families, depsipeptides and stapled peptides are included. In this context, the work presented herein was focused on the development of novel methodologies for the synthesis of depsipeptides and stapled peptides. Up to date, the most general and effective strategy for the preparation of complex cyclodepsipeptides combines solid-phase synthesis and solution chemistry approaches, in which segment condensation is used for the assembly of the building blocks containing the depsipeptide moieties. However, this methodology presents some disadvantages. For instance, the synthetic route must be designed and optimised for each particular case, and therefore a versatile general synthetic method cannot be outlined. Thus, a robust full solid-phase methodology would become a valuable chemical tool for both the preparation of naturally-occurring cyclodepsipeptides and the rapid generation of synthetic analogues. With that purpose, a synthetic analogue of naturally-occurring cyclodepsipeptide YM-254890 was used as a model depsipeptide for the development of such methodology, where the drawbacks commonly encountered during solid-phase depsipeptide synthesis, including: DKP formation, formation of undesired α,β-elimination side-products during Fmoc removal and selection of the optimal protecting group scheme, were extensively studied and solved. Additionally, evaluation of the strategy efficiency was carried out by comparison with conventional segment condensation approaches. Remarkably, similar overall yields as the ones obtained for segment condensation approaches were observed. Thus, the newly developed methodology becomes a versatile and convenient tool for the preparation of complex cyclodepsipeptides. On the other hand, great efforts have been put into the
generation of novel stapled peptides mimicking α-helices. Although extensive research has been carried out in this field, a single universal stapling technique cannot be established, since selection of the most suitable cross-linking approach highly depends on the nature of the protein-protein interaction to be addressed. Nevertheless, the ability of stapled peptides to cross the cell membrane, increase in vivo stability and exhibit improved biological activity, has gained raising interest over the past years. It is well known, that backbone N-modified peptides exhibit greater lipophilicity, which ultimately results in enhanced cell internalisation. Additionally, N-modified peptides present higher resistance against proteolytic degradation. Considering these benefits, we envisioned that insertion of N-methyl-rich peptide bridges would be a good approach to develop a novel class of stapled peptides with an enhanced pharmacokinetic profile. With that purpose, the second part of this work was addressed at the design and development of a novel class of single and double highly N-methylated stapled peptides, or the so-called HMSP. Due to the importance of the p53 tumour suppressor, which activates cell death in response to various stress conditions, the p53-MDM2 protein- protein interaction was the focus in the development of our synthetic methodology. To linear p53-based peptides presenting a random coil secondary structure, several N- methyl-rich peptide bridges of different nature and length were inserted at different positions. Insertion of these staple entities makes these molecular constructs highly versatile, as the nature, length and flexibility of the staple can be modulated by the number and nature of NMe-amino acids. Circular dichroism experiments confirmed that helicity was induced, and allowed evaluation of the helicity increase for each system.Dadas sus propiedades intrínsecas y su atractivo perfil farmacológico, los péptidos y las proteínas, surgen como potenciales agentes terapéuticos para el descubrimiento de nuevos fármacos. No obstante, su explotación en este campo ha sido obstaculizada por su escasa estabilidad y biodisponibilidad. De especial interés, son las modificaciones en el esqueleto peptídico, ya que a menudo dan lugar a propiedades farmacológicas mejoradas, tales como una mayor estabilidad, biodisponibilidad, permeabilidad celular y una menor toxicidad. La presente tesis se centra en los depsipéptidos y péptidos grapa, que se encuentran entre las familias de péptidos más relevantes que presentan modificaciones en el esqueleto peptídico. En el primer proyecto, se desarrolló una metodología robusta en fase sólida, basada en la estrategia Fmoc, para la preparación de depsipéptidos que contienen enlaces éster múltiples y consecutivos. Para ello, un análogo sintético del ciclodepsipéptido natural YM-254890 se designó como modelo para estudiar los inconvenientes comúnmente encontrados en la síntesis de depsipéptidos en fase sólida, que a día de hoy, han obstaculizado la instauración de dicha metodología. Por consiguiente, dificultades como la formación de DKP, la eliminación problemática de Fmoc, la selección del esquema de grupos protectores, entre otras, fueron ampliamente estudiadas y resueltas. En el segundo proyecto, con el fin de inducir la conformación hélice alfa, a la vez que preparar compuestos con un perfil farmacológico mejorado, se abordó el diseño y desarrollo de una nueva clase de péptidos grapa altamente N-metilados, los denominados HMSP. Para ello, entre dos posiciones clave de la secuencia bioactiva del péptido p53, que naturalmente no presenta una estructura secundaria organizada, se introdujeron varios péptidos puente ricos en residuos N-metilo. La estructura hélice alfa fue inducida satisfactoriamente. Por otro lado, la inserción de dichos puentes dio lugar a la preparación de construcciones moleculares altamente versátiles, dado que la naturaleza, la longitud y la flexibilidad del puente pueden ser moduladas por el número y la naturaleza de los aminoácidos N-metilados.
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Yang, Bo. „Field Observations and Novel Methodologies for Carbon System Assessments in Coastal Waters“. Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5804.
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Coastal zones receive massive terrestrial inputs of nutrients and organic matter, and play an important role in biogeochemical cycles. The interactions of river inputs, ocean currents, atmospheric exchanges, anthropogenic influences, and biologically active ecosystems make CO2 system studies in coastal waters highly challenging. This work focuses on improving our understanding of the CO2 system in coastal waters through (1) development of a new methodology for measurements of CO2 system parameters in the field; (2) observations of large spatial and temporal CO2 system variations in coastal waters; and (3) characterization of the influence of organics on CO2 system behavior in coastal waters.
A novel portable light-emitting-diode (LED) photometer was developed to provide low-cost seawater pH measurements in the field. With meta cresol purple (mCP) as the indicator, the photometer produces pHT measurements within ± 0.01 units of state-of-the-art spectrophotometric measurements (7.6 ≤ pH ≤ 8.2, 30 ≤ S ≤ 36.2, and 15 oC ≤ t ≤ 30 oC). With a simple “do-it-yourself” (DIY) construction design, a hundredfold reduction in cost relative to benchtop spectrophotometric systems, and routine calibration-free operation in the field, the DIY photometer is an ideal replacement for pH test strips or consumer-level potentiometric probes. Applications of special interest include education, citizen science, coastal zone monitoring, and aquaculture and aquarium management.
Subannual variability of total alkalinity (TA) distributions in the northeastern Gulf of Mexico (GOM) was examined through the use of TA data from ship-based water sampling, historical records of riverine TA, and contemporaneous model output of surface currents and salinity. Variability of TA observed in the upper 150 m of the GOM water column was primarily controlled by subannual variations in the extent of mixing between seawater and river water. A transition in TA distribution patterns between the river-dominated northern margin (near the Mississippi–Atchafalaya River System) and the ocean current-dominated eastern margin (West Florida Shelf) was observed. A riverine alkalinity input index was developed to highlight riverine TA contributions.
Contributions of organic alkalinity (Org-Alk) to TA were investigated in coastal waters from three different environments (estuary, urban, mangrove) and offshore sites in the Gulf of Mexico. The difference in alkalinity (∆TA) between TA measured by direct titration (TAmeas) and calculated (TAcal) from observations of DIC and pH was used as an estimate of Org-Alk. Average values of ∆TA were 0.1 ± 5.0 µmol kg-1 at coastal sample sites outside the Mississippi-Atchafalaya River Estuary (n = 17), 1.9 ± 5.2 µmol kg-1 in offshore waters (n = 14) in the northern Gulf of Mexico, 33.6 ± 18.0 µmol kg-1 in the Suwannee River Estuary (n = 17), and 16.0 ± 25.4 µmol kg-1 in sites that included Tampa Bay, the Caloosahatchee River, and the Ten Thousand Islands area (n = 55). In addition to Org-Alk assessments based on measurements of ∆TA, a novel two-step spectophotometric titration method was developed for the characterization of Org-Alk. Direct titrations showed substantial Org-Alk in coastal samples (n = 5), and the Org-Alk values obtained from the two-step titrations showed good agreement with results from ∆TA calculations. The spectrophotometric titration data were used in model fits to evaluate the dissociation constants (pKi) of the natural organic acids. The pKi of the organic acids were within the previously reported range for riverine fulvic acids.
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Roche, Philip Jonathan Rupert. „Development of novel optical sensor methodologies for assessment of cytochrome p450 monoxygenases“. Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488778.
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Mould, Jessica. „Development of novel solid-phase methodologies for the generation of combinatorial libraries“. Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285600.
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Moorkanikkara, Srinivas Nageswaran. „Development of novel methodologies to analyze the adsorption kinetics of nonionic surfactants“. Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42166.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2007.Includes bibliographical references.
When an aqueous surfactant solution is exposed to a clean water/air surface, it takes a finite time for the surfactant molecules to physically transport from the bulk aqueous solution to the surface in order to adsorb and reduce the surface tension. The time scales associated with the reduction in surface tension can vary between milliseconds to hours depending on the surfactant type and its concentration. Accordingly, development of a fundamental understanding of the underlying physical phenomena involved in the kinetics of surfactant adsorption will help to: (i) understand the observed Dynamic Surface Tension (DST) behavior of surfactants, and (ii) design optimal surfactant formulations for applications in which the surfactant adsorption kinetics plays a significant role in determining the effectiveness of the formulation. This thesis deals with modeling the adsorption kinetics of nonionic surfactants at prernicellar surfactant concentrations. Traditionally, the adsorption kinetics of nonionic surfactants at premicellar surfactant concentrations has been understood in the context of two models: (1) the diffusion-controlled model, which assumes that diffusion of surfactant molecules from the bulk solution to the surface is the rate-limiting step, and (2) the mixed diffusion-barrier controlled model, which hypothesizes the existence of an energy barrier for surfactant adsorption from the bulk solution to the surface, and assumes that both diffusion and the energy barrier determine the overall rate of surfactant adsorption. Although the existence of the energy barrier was hypothesized more than 50 years ago, the physical basis underlying the existence of the energy barrier has not yet been elucidated.
(cont.) The first major contribution of this thesis was demonstrating that the energy barrier is associated with the adsorption of a single surfactant molecule onto a clean surface, contrary to the broadly-held view that the energy barrier is associated with collective interactions between the adsorbed surfactant molecules. This was demonstrated by developing a generalized mixed diffusion-barrier controlled model and deriving a short-time adsorption kinetics formalism for this generalized model. The short-time formalism revealed that, when adsorption takes place onto an initially clean surface, the adsorption kinetics is independent of the specific interactions between the adsorbed surfactant molecules, and is solely controlled by the energy barrier at asymptotic short times. This observation led to the important conclusion that the energy barrier is related to the adsorption of a single surfactant molecule onto a clean surface. One of the major drawbacks with the traditional procedure to determine the adsorption kinetics rate-limiting mechanism (diffusion-controlled vs. mixed diffusion-barrier controlled), including the values of the relevant adsorption kinetics parameters, from experimental DST data is that it requires a specific model for the equilibrium adsorption behavior of the surfactant, where the deduced results were found to be extremely sensitive to the accuracy of the specific equilibrium model used. As a result, it has not been possible to elucidate the underlying physical basis of the energy barrier by analyzing the experimental DST data of nonionic surfactants.
(cont.) With this limitation in mind, the second major contribution of this thesis was the development of a new methodology to determine the adsorption kinetics rate-limiting mechanism, including the values of the relevant adsorption kinetics parameters, from the experimental DST data without using any model for the equilibrium surfactant adsorption behavior. The new methodology was implemented to analyze the experimental DST behavior of several alkyl poly(ethylene) oxide, CiEj, nonionic surfactants, and revealed that the energy barrier may be related to the hydrophobic effect. The third major contribution of this thesis was the development of a novel approach to determine the equilibrium adsorption properties of nonionic surfactants from experimental dynamic surface tension data, a novel concept which has never been explored in the surface tension literature. Motivated by the observed high sensitivity of the predicted DST profiles to the accuracy of the model used to describe the equilibrium surfactant adsorption behavior, a new methodology was developed to determine the Equilibrium Surface Tension versus surfactant bulk solution Concentration (ESTC) behavior of nonionic surfactants from experimental DST data when the adsorption kinetics rate-limiting mechanism is diffusion-controlled. The new methodology requires: (1) experimental DST data measured at a single surfactant bulk solution concentration, Cb, (2) the diffusion coefficient of the surfactant molecule, and (3) one equilibrium surface tension value measured at a single surfactant bulk solution concentration, to determine the entire ESTC curve corresponding to surfactant bulk solution concentrations which are less than, or equal to, Cb. The new methodology was implemented to analyze the experimental pendant-bubble DST data of C12E4 and C12E6.
(cont.) For this purpose, the time scale associated with the validity of the assumption involving diffusive transport of surfactant molecules in the bulk solution in a pendant-bubble DST measurement was first determined, and the experimental DST data at those time scales was analyzed using the new methodology to predict the ESTC curves of C12E4 and C12E6. In both cases, the predicted ESTC behavior compared very well with the appropriate experimental DST results reported in the literature. The final major contribution of this thesis was the development of a novel theoretical framework to design optimal surfactant formulations that meet specific adsorption kinetics requirements, which circumvents the more widely used and time consuming experimental trail-and-error surfactant selection approach. Specifically, the new theoretical framework involves using predictive DST models in conjunction with optimization techniques to identify the most efficient surfactant formulation that meets a specific surfactant adsorption kinetics requirement. The technical feasibility of the new theoretical framework and its effectiveness was demonstrated in the context of the adsorption kinetics of nonionic surfactants. Overall, the results obtained in this thesis contribute to: (1) the development of a fundamental physical understanding of the energy barrier, (2) the development of efficient and reliable methodologies to more accurately analyze experimental DST data, and (3) the design of optimal surfactant formulations in industrial applications.
by Srinivas Nageswaran Moorkanikkara.
Ph.D.
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Counceller, Carla Marie. „Development of Novel Methodologies for the Synthesis and Functionalization of Nitrogen Heterocycles“. The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275047798.
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Lamarre, Neil Stanley. „Utilizing novel dose equivalence methodologies to examine cocaine's effects on the vasculature“. Diss., Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/221180.
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PharmacologyPh.D.
ABSTRACT: UTILIZING NOVEL DOSE EQUIVALENCE METHODOLOGIES TO EXAMINE COCAINE'S EFFECTS ON THE VASCULATURE Neil S. Lamarre Doctor of Philosophy Temple University School of Medicine, 2013 Doctoral Advisory Committee Chair: Ronald J. Tallarida, Ph.D. Cocaine abuse and addiction is a serious health problem, resulting in thousands of emergency room visits and deaths each year in the United States. It is particularly toxic to the cardiovascular system, including deleterious effects on the peripheral vasculature. These effects are not well understood, but evidence suggests chronic cocaine use may lead to endothelial dysfunction, thereby increasing relative risk of a number of other cardiovascular diseases including stroke, aneurysm, myocardial infarction, hypertension, etc. Data from our lab, and others, suggest that the presence of a functional endothelium has a dramatic effect on the contractility of the rat aorta that is agonist-specific. Attenuation of this endothelium-dependent vasodilatory component of agonist action is a primary feature of endothelial dysfunction. We have utilized dose equivalence theory to calculate the dose response relationship for the endothelium-dependent vasodilatory component of an agonist causing overt vasoconstriction. This component cannot be measured directly, but our novel methodology allows us to quantitate agonist-specific impairment of vasodilation, and describe it using the familiar parameters of the dose response curve. Another strength of this method, relative to currently used in vitro methods, is that it also avoids the confounding variable of a second agonist used to produce the initial vasoconstriction. To validate the methodology, a pilot study was performed examining the endothelial dysfunction in STZ-induced diabetic rats, as a positive control for endothelial dysfunction. Interestingly, this treatment showed impairment in the endothelium-dependent vasodilatory component of action of norepinephrine, but not of angiotensin-II. Thus, our initial hypothesis was confirmed - that disruption of the vasodilatory components of various agonists are independent, and that agonist-specific information may prove useful. Next, we employed our new methodology utilizing the rat aorta as our vascular model to test the hypothesis that chronic cocaine administration causes endothelial dysfunction. We first examined the endothelium-dependent vasodilation component of a number of physiologically important vasoconstrictors, and attempted to determine which vasodilatory mediators contributed to the effect. We found the endothelium to have a profound effect on the dose response curve to three important endogenous agonists. These data suggest that under conditions of endothelial dysfunction exaggerated vasoconstriction could occur, even within normal plasma concentration ranges of these vasoconstrictors, resulting in elevated blood pressure and further damage to the endothelium over time. No endothelial dysfunction was observed with this treatment paradigm, using our methodology or the standard approach. This may be a result of insufficient duration of cocaine treatment, or a result of our selection of the rat aorta as a model. We wanted to further investigate which vasodilatory mechanisms were involved in this vasodilatory component of action. We inhibiting various endothelium-derived mediators of this vasodilatory component of action (such as nitric oxide or prostacyclin), which revealed differential activation of these mediators by the agonists examined. For example, inhibition of nitric oxide synthesis abolished the endothelium-dependent vasodilatory component of endothelin-1, but only partially attenuated that of angiotensin-II. Thus, the agonist-specific pattern of impairment may also prove useful in examining the underlying mechanisms of impaired vasodilation. Endothelial dysfunction is one reported consequence of long term cocaine abuse; however, there are conflicting reports on the acute vascular effects of cocaine, with some reports concluding that cocaine is a vasoconstrictor, and some reporting its action as a vasodilator. There are in vitro reports of cocaine causing release of vasoconstrictors from the endothelium, which supports the longstanding notion of cocaine as a vasoconstrictor. However, one recent report demonstrates a dose-dependent vasodilatory effect of cocaine in rat aorta that is independent of the endothelium. This complexity is perhaps due, in part, to cocaine's affinity for a number of molecular targets, acting in combination. In examining the acute action of cocaine in our preparation, we observed an "inverted-U" shaped dose response, also referred to as a hormetic dose response curve. We then applied dose equivalence methodology in order to derive the "unknown" second component contributing the vasodilatory action of cocaine at higher doses. This methodology lets us calculate this unknown component, and describe it with the familiar parameters of a dose response curve, which could potentially aid in the identification of the unknown component. The preliminary studies with acute cocaine utilized a sub-maximal dose of phenylephrine in order to observe tension changes in either direction. This prompted us to further characterize the interaction of cocaine with other alpha adrenoceptor agonists. Importantly, because cocaine alone had no effect at doses up to 100 µM, but potentiated the vasoconstriction of alpha agonists, the interaction is therefore synergistic. This constitutes evidence of a previously undescribed mechanism contributing to cocaine's vasoconstricting effect. In vivo, reuptake inhibition is a major mechanism for cocaine-induced vasoconstriction, but is excluded in this experiment by virtue of low levels of sympathetic innervation in the rat aorta, and the use of methoxamine, an alpha agonist not subject to the reuptake mechanisms. This interaction may contribute to cocaine-induced vasoconstriction in the coronary arteries, especially in circumstances of endothelial dysfunction. In summary, the work presented in this dissertation applies new methodologies utilizing dose equivalence theory to the study of cocaine's effects on peripheral vasculature, and presents novel findings of synergy with respect to cocaine's enhancement on the action of alpha adrenoceptor-mediated vasoconstriction.
Temple University--Theses
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Lessi, Cheimariou Angeliki. „Optimal treatment of nonlinear site response through a set of novel methodologies“. Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/30818.
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Different methods of analysis, such as site-specific site response analysis or the use of ground-motion prediction equations can be adopted to account for the modification of the seismic ground-motion by the near-surface stratigraphy. Each approach is associated with a different degree of complexity and associated computational and temporal cost. This thesis identifies the main limitations of these methods as broadly employed in both academia and industry and suggests a new set of methodologies for their application. In the first part of the thesis ground-motion prediction equations and their ability to model response associated with site-specific soil layering is broadly assessed. Special emphasis is paid to the description and application of the Vs-κ_0 adjustment. This ensures that the response of a ground-motion model, particularly in the upper frequency range, is representative of the characteristics of a given site-specific shallow crustal profile. Then the effect of employing a standard deviation representative of a single site is examined. This is based on the removal of the site-ergodic assumption from the published standard deviations of the models. The effect on the hazard curves and any further implications of using this site-specific standard deviation is demonstrated by performing a Probabilistic Seismic Hazard Assessment. The second part of the thesis focuses on the main limitations and ranges of applicability of 1D site-specific site response analysis. Firstly, the Equivalent Linear approximation and the Nonlinear analysis for the constitutive modified model of Kodner and Zelasko (Matasovic and Vucetic, 1993) are tested for different magnitude-distance scenarios and strain ranges. The uncertainty in the different soil properties within site-specific site response analyses and their effect on the surface predictions is also quantified. As a result, a new set of period and soil-class dependent adjustment factors are developed which can be used as an alternative to approaches based upon randomisation of the dynamic soil properties. As part of the performed analyses, the potential bias introduced through the scaling of input motions, used in site response analysis, is addressed. Finally, the significance of using different reference depths within 1D site response analysis is considered. Consequently, through progressively more complicated parametric analyses, two new approaches, are established. These can be employed individually or in combination to select a depth for site investigation as well as a reference depth for site response analysis. Ultimately, the surface spectral ordinates obtained using site response analyses and ground-motion prediction equations are compared for an active tectonic region. Each of the previously developed methods is applied in the examined case study and the results are assessed against the traditional application of the methods. In addition, the surface predictions of each of the different methods of analysis are examined in relation to their uncertainty. This comparative analysis allows one to address the question of whether increased complexity in site-response analysis has a justifiable reward in terms of the reduction of uncertainty and also enables one to identify the most appropriate level of complexity to adopt for a given project.
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Zhu, Weihua. „Design and development of novel routing methodologies for dynamic roadway navigation systems“. Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3350082.
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Thesis (Ph. D.)--University of California, Riverside, 2009.Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 12, 2010). Includes bibliographical references (p. ). Also issued in print.
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ATTARD, TREVISAN ADRIAN. „NOVEL COMPUTATIONAL ELECTROENCEPHALOGRAPHIC (EEG) METHODOLOGIES FOR AUTISM MANAGEMENT AND EPILEPTIC SEIZURE PREDICTION“. Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/333759.
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The doctoral thesis deals with a novel methodology of looking and processing electroencephalographic (EEG) data. The first part deals with real-time brain stimulation in the form of a sonified neurofeedback therapy derived from a clinically comparable portable, 4-channel EEG system. The therapy aims to provide an effective management for symptoms of the Autism Spectrum Disorder (ASD). ASD is characterized with a high level of delta electroencephalographic waveform levels, while alpha and beta prove to be present at lower levels especially in the frontal-temporal regions. The treatment aims at lowering delta waves and promoting alpha and beta waveforms. The second part of the thesis focuses on using EEG data in the prediction of epileptic seizures. With the help of custom built algorithms and neural networks, an effective prediction of an epileptic seizure can be achieved.
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Mahajan, P. S. „Synthesis of bioactive natural products cleistenolide, isocryptolepine and circumdatins using novel methodologies“. Thesis(Ph.D.), CSIR- National Chemical Laboratory, Pune, 2018. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/4511.
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Smith, Christopher John. „Development of novel methodologies for using ICP-MS in bioanalysis and drug metabolism“. Thesis, Sheffield Hallam University, 2005. http://shura.shu.ac.uk/20377/.
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Inductively coupled plasma mass spectrometry (ICP-MS) has been widely used for environmental and trace analysis since its introduction in the early 1980s. This thesis describes an exploration of the potential of HPLC-ICP-MS within the pharmaceutical industry. Determination of platinum in the anticancer drug ZD0473 was performed in comparison with conventional HPLC-MSMS, investigating limit of detection, linearity and reproducibility on spiked samples. Both methods were capable of providing accurate and precise results with samples from rats dosed intravenously 0.5 mg/kg and orally at 6 mg/kg, but the HPLC-ICP-MS Pt method had extended linear range and superior sensitivity, providing a limit of quantification of 0.1 ng/mL compared to 5 ng/mL by HPLC-MSMS. Impurity and metabolite profiles for ZD0473, using platinum as a marker with HPLC-ICP-MS, were compared to profiles from 14C-labelled compound with radioactivity detection, showing that the compound was converted to 2-picoline. Since the number of compounds containing platinum found in the pharmaceutical industry is limited ICP-MS was then evaluated for other elements. The detection of carbon was investigated, since this is present in all organic molecules, and a limit of detection of 0.47 mumol of carbon was achieved for sulphanilamide using superheated water as the mobile phase. Isotopically enriched solvents (12C-methanol 99.95 atom %) were used as organic modifier to aid chromatography. Detection limits of 86 mumol for 13C-triple-labelled caffeine and 79 mumol 13C-double-labelled phenacetin. Halogen (Br, I and Cl) detection was investigated. Metabolite profiling and excretion balance studies were carried out using these elements after dosing suitable model compounds (substituted anilines and benzoic acids) to rats. Limits of detection for Br and I were measured down to 0.1 mM. Profiling for 2-, 3-, 4-bromobenzoic acids showed glycine and glucuronide metabolites, in different proportions dependant on the position of the Br. This was also seen for the 2-, 3-, 4-iodobenzoic acids. Sulphur and phosphorous containing drugs were analysed using the reaction cell of the ICP-MS to chemically enhance the signal by reacting the element with oxygen (e.g. to give SO[+]), moving the detection away from a region of isobaric interference. Metabolite profiling of omeprazole was performed, with limits of detection of 800 pg of sulphur on column (an improvement of 100 fold in sensitivity from detection without oxygen). Similar studies with phosphorus containing drugs also showed a significant increase in sensitivity following reaction with oxygen compared to conventional analysis by ICP-MS.The studies undertaken here demonstrate the significant potential of HPLC-ICP-MS as a contributor to the analysis of drugs and metabolites in the pharmaceutical industry.
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Bidder, Owen R. „A movement ecology toolkit : novel biotelemetry methodologies for elucidating animal behaviour and location“. Thesis, Swansea University, 2014. https://cronfa.swan.ac.uk/Record/cronfa42816.
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This thesis aims to address some of the deficiencies that exist in this discipline, in order to widen the applicability of biotelemetry methods and ultimately provide new data which will improve our understanding of animal movement strategies.
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De, Nisi Assunta <1987>. „Novel insights into gold(I) chemistry: from anticancer activity to new synthetic methodologies“. Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amsdottorato.unibo.it/8597/1/DNA%20PhDFull14mar18.pdf.
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The work herein presented, embraces various aspects of gold chemistry: the documentation of novel [alkynyl(triphenylphosphine)gold(I)] complexes carrying differently substituted propargylic amines and their pharmacological investigation on a series of cancer cell lines and the investigation of the dearomative cycloaddition reaction of indoles with electron-rich allenes catalysed by commercially available gold(I) complexes that show competence in performing the chemo-, regio- and diastereoselective formal [2+2]-cycloaddition between a wide range of substrates under mild conditions. It has also been developed the combined efficiency of Bu4N+ and F− ions in performing a cascade sequence involving intramolecular hydroamination of the C–C triple bond, cleavage of silyl-protecting groups and site-selective sigmatropic aza-Cope-type [3,3]-rearrangement.
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Usman, Muhammad. „Novel Methodologies for the Analysis and Management of Low Voltage Active Distribution Networks“. Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3424891.
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The continuous proliferation of renewable Distributed Energy Resources (DERs) in Medium Voltage (MV) and Low Voltage (LV) Distribution Networks (DNs) is playing a prominent role in reducing the carbon footprint of fossil-fuel-based electricity generation plants. However, the rapid integration of these resources has also changed the passive nature of these networks, and consequently, special attention is required to ensure their optimal, secure and reliable operation. Moreover, the installed DERs cannot be simply operated on the basis of a fit-and-forget policy due to the emergence of several technical problems caused by their interconnection. Issues such as voltage unbalance, reverse power flow, unintentional islanded operation etc. are frequently occurring in these networks which, in turn, require novel control and management schemes to ensure the continuous supply of electricity to end-users. In this context, several countries and network operators have updated their grid codes which put additional constraints on renewable DERs to participate in the provision of ancillary services in the context of maintaining network stability.
In view of this, multi-phase analysis of MV and, especially, LV networks gains unprecedented attention due to the non-capability of single-phase equivalent representation-based network analysis approach in depicting the true picture of system’s operating conditions and state variables. Such a detailed network analysis, in turn, sets the path for innovative solutions to effectively manage these networks. Furthermore, concerning LV DNs, neutral conductor must be treated like phases conductors due to the significant presence of current in it under highly unbalanced network loading scenario. Resultantly, the application of the Kron reduction methodology to these networks must be avoided because of its reliance upon the unrealistic assumption of an equipotential neutral conductor. Since LV active DNs will become a central pillar of a decentralized electrical grid in near-future, it is, therefore, incumbent to analyse and manage them by taking into account each aspect of their structure.
With a special emphasis and focus on LV active DNs, this thesis presents novel analysis and management techniques for such networks by taking into account the explicit representation of both phases and neutral conductors in the context of losses management, which includes both losses minimization and losses allocation concepts in its scope. Regarding the latter notion, a novel multi-phase losses allocation procedure is proposed which avoids allocating neutral losses to phases conductors and, consequently, provides explicit information about phase- and neutral-losses allocation factors. The proposed approach successfully takes into account the impact of unbalanced loading through self- and mutualvariable losses coefficients while allocating losses to end-users. Based on the information provided by positive neutral losses allocation factors, a novel unbalance reduction strategy is further developed which allows the commutation of loads from heavily loaded phases of a critical node to its lightly loaded phases and, therefore, improves network balancing significantly.
In the framework of losses reduction, a multi-phase Optimal Power Flow (OPF) model based on Semi-Definite Programming (SDP) technique is formulated which successfully incorporates neutral conductors as well as wye- and delta-connected loads in its formulation. Moreover, a novel complex voltage variable-based approach is proposed for the incorporation of a complete ZIP load in the proposed relaxation. However, due to excessively high computational requirements of this relaxation in the case of medium- and large-size DNs, a cheap SDP-based OPF model is additionally proposed and three novel propositions are developed in this context for the modelling of constant current loads. The proposed cheap relaxation can be practically realized due to its low computational requirements and provision of exact solution under a range of ZIP load parameters. However, due to the dominance of multi-phase SDP-based approach over cheap SDP-based relaxation, the latter relaxation is further tightened by imposing additional constraints in the form of convex envelopes. As a result, a tight solution is obtained without making any compromise on the computational benefits of cheap SDP-based OPF relaxation.
Finally, all the proposed strategies are simulated on several test cases to demonstrate their positive potential in the context of LV active DNs management.
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Chao, Sam. „Novel data mining methodologies for medical data processing and application on i+diagnostic workbench“. Thesis, University of Macau, 2008. http://umaclib3.umac.mo/record=b1872954.
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McPherson, Christopher. „The development of novel organocatalytic and transition-metal catalysed methodologies for amide bond formation“. Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30294.
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With the formation of amide bonds being one of the most widely performed reactions within organic chemistry, highly efficient and atom economical approaches enabling the transformation are desired. Traditional methodologies, in which a stoichiometric coupling reagent is utilised, although efficient, have several inherent drawbacks hindering their general applicability, including stoichiometric by-product formation, low atom economy and poor cost effectiveness. Therefore, the development of atom economical catalytic approaches to facilitate the facile synthesis of amide bonds would successfully address the aforementioned outstanding issues. Building upon previous research performed within the Jamieson group, one such approach is the trifluoroethanol-catalysed amidation of unactivated ester derivatives. However, in the initial studies, the general applicability of this methodology was limited by the incompatibility of acyclic secondary amines under the reaction manifold, and additionally, stereoerosion when the use of α-stereogenic ester substrates was examined. Further optimisation of the progenitor conditions successfully addressed these limitations, allowing the synthesis of a diverse range of acyclic tertiary amides and chiral secondary amides, with the latter synthesised in good to excellent levels of stereoretention (Scheme 1.1). Additionally, a multicomponent approach enabling the formation of secondary amides fromepoxides, amines and unactivated esters, mediated by the organobase BEMP, has also been developed. The use of a multicomponent process, employing only catalytic quantities of base, limits by-product formation, thereby resulting in a highly atom efficient amide bond forming method (Scheme 1.2). This approach has also been further adapted to enable the synthesis of corresponding oxazolidinone moieties. The use of transition-metal catalysis has also been employed to facilitate amide bond formation. Utilising silanoate-derived imidate salt species, synthesised from the corresponding nitriles as amide surrogates, a Buchwald-Hartwig amidation methodology has been developed, enabling the synthesis of secondary amides (Scheme 1.3). Investigations into the use of these species in other amide bond forming transformations have also been carried out.
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Mondal, Biswajit. „Novel pd-catalyzed carbon-carbon and carbon-heteroatom cross coupling reactions towards the synthesis of diverse functional molecules“. Thesis, University of North Bengal, 2021. http://ir.nbu.ac.in/handle/123456789/4373.
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Somma, Maria Salvatrice. „Novel methodologies for the synthesis of porphyrins and chlorins and spectroscopic studies of nonplanar porphyrins /“. For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Alkhalil, Aalae. „Application of the quality control methodologies to a novel solid dosage co-crystal model system“. Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13362/.
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Co-crystals are multi-component, single phase materials in which the co-crystal formers exist in an uncharged state. This interaction between components occurs without affecting the intra-molecular covalent bonding of the involved components or altering their chemical integrity. This class of materials has recently gained the interest in the pharmaceutical industry for modifying the physico-chemical properties of some active pharmaceutical ingredients (APIs) such as solubility, hygroscopicity, and mechanical properties. However like all multi-component systems, there are some analytical challenges associated with using traditional quality control (QC) tools that involve sample preparation steps prior to the analysis. This can sometimes have an impact on the physical state of such systems and therefore affect the outcomes of analysis correlated with the actual materials. Flurbiprofen (FBP) and nicotinamide (NCT) in this work were selected to form a model co-crystal system. FBP falls in the carboxylated group of non steroidal anti-inflammatory drugs (NSAIDs), used herein as an API. It belongs to class II of the Biopharmaceutics Classification System (BCS), therefore its low aqueous solubility and dissolution rate affect its bioavailability. NCT is a vitamin B3 derivative and generally regarded as safe (GRAS) substance. It is used as co-crystallising agent due to its solubility enhancing property. FBP-NCT co-crystal system was previously studied by Berry et al., where a FBP-NCT co-crystal was prepared using Kofler method and screened by means of the hot-stage microscopy (HSM). FBP-NCT co-crystal was recently prepared via rapid evaporation from ethanol solution, and screened for its physicochemical and mechanical properties by Shing et al. who found an improvement in such properties compared to the pure API (FBP). There is a wide range of methods for preparing co-crystals, of which methodologies with minimal environment impact were mainly adopted in this work i.e., Ko er fusion and co-grinding methods. Within the Kofler fusion method, it was feasible to identify and screen simultaneously parent components as well as the emerging material at room temperature (RT) by means of confocal Raman microscopy. Detailed information from Raman mapping on the investigated phases were achieved using statistical analysis. The analysis resulted in a refinement regarding the traditional assumption about the binary phase diagram. It also revealed the presence of two forms of FBP-NCT co-crystals which were consequently explored by coupling thermal analysis with Raman spectroscopy and X-ray diffraction. Using co-grinding preparation, FBP-NCT co-crystals were prepared on a large scale; enough for solid dosage formulation. Subsequent crystallisation of the resulting compound using a solution method generated single crystals suitable for x-ray crystal structure determination. Moreover in this work, a solid-state dosage form of FBP-NCT co-crystal was prepared for the first time, then investigated using transmission Raman spectroscopy. The investigation included the presence of drug and excipient, and their composition in tablets. This procedure can be considered as a platform for studying the QC of drug preparation, using a reliable, non-destructive, non-invasive, and very rapid analytical tool. Such type of study complied well with the food and drug administrative (FDA) outlines on employing process analytical technology (PAT) protocol for analysing and controlling pharmaceutical manufacturing processes.
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McClean, Jennifer Natalie. „Novel isothermal PCR methodologies for the selective detection and analysis of microorganisms in environmental samples“. Thesis, Queen's University Belfast, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557957.
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SUMMARY (To be printed on this form) Phosphoramidite derivatives of a nucleoside analogue bearing photoswitchable ortho, meta and para-azobenzene moieties were synthesized and used to incorporate the photoswitchable azobenzene group proximal to the 5' and 3' ends of deoxyoligonucIeotide primers (12mers) of the glyceraldehydes-3-phosphate dehydrogenase (GAPDH) gene. The photochemical E~Z isomerisation of azobenzene appended primers was investigated by UV/vis spectroscopy and RP-HPLC. Melting studies were also performed to determine the Tm of the primers. Isothermal primer extension reactions were performed with Klenow fragment at the dark- adapted and irradiated photo stationary states. This revealed that only the para-azobenzene perturbed the extension by the enzyme. Further investigation with time course experiments to determine a yield using fluorescent fluorescein label and explore the possibility of photoswitchable DNA amplification using the para-azobenzene primers. OligonucIeotides bearing a novel photoswitchable moiety, phenylazopyridine, have been prepared. Directed Michaelis-Arbuzov reactions of support-bound internucleotide phosphite triesters with alkane-diamines were effected in the presence of iodine. The primary amine functionalised oligonucleotides were subsequently purified trityl on. This enabled resolution offast- and slow-isomers of oligomers.
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Baumann, Marcus. „Development of novel flow methodologies for the synthesis of natural products and new chemical entities“. Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609165.
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Swamy, V. P. „Novel synthetic methodologies: regio- and stereoselective synthesis of organic compounds using zeolites, organometallics & ultrasound“. Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1997. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3362.
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