Dissertations / Theses on the topic 'Synthetic Modification'
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Keenan, Luke. "Post-synthetic modification of metal-organic frameworks." Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619226.
Full textAbdelhameed, Reda Mohamed. "Post-synthetic modification of metal–organic frameworks." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/15516.
Full textPost-synthetic modification (PSM) of metal-organic frameworks encompassing the chemical transformation of the linker present is a promising new route for engineering optical centres and tuning the light emission properties of materials, both in the visible and in the near infrared (NIR) spectral regions. Here, PSM of isoreticular metal-organic framework-3 (IRMOF-3) with ethyl oxalyl monochloride, ethyl acetoacetate, pentane-2,4-dione, 3-(2- hydroxyphenyl)-3-oxopropanal, 2-chloroacetic acid, glyoxylic acid, methyl vinyl ketone and diethyl (ethoxymethylene)malonate followed by chelation of trivalent lanthanide ions afforded intriguing near infrared (Nd3+) and visible (Eu3+, Tb3+) light emitters. IRMOF-3 was used as a case in point due to both its highly porous crystalline structure and the presence of non-coordinating amino groups on the benzenedicarboxylate (bdc) linker amenable to modification. The materials were characterised by elemental analysis, powder X-ray diffraction, optical, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, and liquid and solid-state nuclear magnetic resonance. The solid-state luminescence properties of Ln-modified-IRMOF-3 were investigated at room temperature. The presence of the bdc aromatic ring, β– diketonate and oxalate enhanced the Ln3+ sensitization via ligand-to-metal energy transfer (anthena effect). As far as photocalysis is concerned, we have synthesized metal−organic frameworks (Cr-MIL-125-AC, Ag-MIL-125-AC) by a green method (solid–vapors reactions). The resulting functionalized materials show a photocatalytic activity for methylene blue degradation up to 6.52 times larger than that of the commercial photocatalyst hombikat UV-100. These findings open the door for further research for improving the photocatalytic performance of metal-organic frameworks.
A modificação pós-síntese de estruturas metalo-orgânicas compreendendo na transformação do ligando orgânico presente é uma nova e promissora via para a engenharia de centros ópticos, permitido sintonizar as propriedades de emissão de luz de materiais na região do visível e do infravermelho próximo. Nesta dissertação, procedeu-se à modificação pós-sintética da estrutura isorreticular metal-orgânica-3 (IRMOF-3) com 2-cloro-2-oxoacetato de etilo, acetoacetato de etilo, pentano-2,4-diona, 3-(2-hidroxifenil)-3-oxopropanal, ácido 2-cloroacético, ácido glioxílico, metilvinil cetona e (etoximetileno)malonato de dietilo, seguida da quelação com iões lantanídeos trivalentes, a qual originou interessantes emissores de luz na região do infravermelho próximo (Nd3+) e do visível (Eu3+, Tb3+). O IRMOF-3 foi usado como um caso de estudo devido quer à sua a estrutura cristalina que apresenta considerável microporosidade, quer à presença de grupos amino livres no ligando benzenodicarboxilato (bdc), que são passíveis de modificação. Os materiais foram caracterizados por análise elementar, difracção de raios X de pós, microscopias óptica, electrónica de varrimento e de transmissão, espetroscopias de infravermelho com transformadas de Fourier e de ressonância magnética nuclear (estados líquido e sólido). As propriedades de luminescência dos materiais Ln-IRMOF-3-modificados foram estudadas à temperatura ambiente. A presença do anel aromático bdc, β- dicetonato e oxalato reforça a sensibilização do Ln3+ através da transferência de energia do ligando para o metal (efeito antena). No que respeita à fotocatálise, sintetizaram-se novos materiais metal-orgânicos (Cr-MIL-125-AC, Ag-MIL-125-AC) através de uma reação sólido-vapor. Estes materiais apresentam uma excelente atividade fotocatalítica para a degradação de azul de metileno até 6,52 vezes maior que o fotocatalisador comercial hombikat UV- 100. Estes resultados abrem a porta a novos estudos que visam melhorar a actividade fotocatalítica de materiais metalo-orgânicos.
Skrifvars, Mikael. "Synthetic modification and characterisation of unsaturated polyesters." Helsinki : University of Helsinki, 2000. http://ethesis.helsinki.fi/julkaisut/mat/kemia/vk/skrifvars/.
Full textArgyle, Iain. "Synthetic membrane performance modification by selective species adsorption." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.665413.
Full textZhang, Zhenjie. "Template-Directed Synthesis and Post-Synthetic Modification of Porphyrin-Encapsulating Metal-Organic Materials." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5162.
Full textAmer, Hamzah Harina. "Functionalisation of metal-organic frameworks via post-synthetic modification." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723333.
Full textQuader, Sabina, and N/A. "Selective Synthetic Modification of Aminoglycosides for Drug Targeting to Tuberculosis." Griffith University. School of Biomolecular and Physical Sciences, 2007. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20071024.151619.
Full textWashington, Benny Jr. "Enzymatic modification of synthetic mRNA's and their interaction with proteins." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 1985. http://digitalcommons.auctr.edu/dissertations/1244.
Full textQuader, Sabina. "Selective Synthetic Modification of Aminoglycosides for Drug Targeting to Tuberculosis." Thesis, Griffith University, 2007. http://hdl.handle.net/10072/367086.
Full textThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Faculty of Science, Environment, Engineering and Technology
Full Text
Xu, Heng. "Post-Synthetic Modification of Metal-Organic Frameworks by Solid-Gas Ozonolysis." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667135.
Full textThis present PhD Thesis has been dedicated to the exploration and study the solid-gas phase ozonolysis as a quick, simple and versatile method for post-synthetic modification of metal-organic frameworks (MOFs). In the first Chapter, a brief introduction to the origin of MOFs is given, followed by typical concepts for design and synthesis of the porous materials. We then pay special attention to the current methodologies that used for post-synthesic modifications of MOFs with state-of-the-art advancements and selected examples, aiming to place the reader in the context of the thesis. Additionally, the main applications of post-synthetically functionalized MOFs are provided. In Chapter 2, the general and specific objectives of the Thesis are introduced. In Chapter 3, we develop a new post-synthetic methodology for functionalization of MOFs based on the solid-gas ozonolysis. The generated ozonide rings are identified by nuclear magnetic resonance (NMR) technique. Moreover, the generality of this method has been proven by a single-crystal-to-single-crystal transformation, as confirmed by single-crystal X-Ray diffraction together with density functional theory (DFT) calculation. Finally, the amenability of ozonide functionality is demonstrated by selectively workup treatment. Chapter 4 extends the use of the solid-gas ozonolysis to post-synthetic modification of MOF porosity. We show that, by carefully selecting mixed-ligand Zr-fcu-MOFs based on organic ligand pairs in which one ligand has ozone-cleavable olefin bonds and the other ligand is ozone-resistant, we were able to selectively break the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within MOF framework. Thus, the mesoporous MOFs are subsequently created through removal of ligand fragments by washing or sublimation, as evidenced by their distinct gas sorption properties.
Albalad, Alcalá Jorge. "Post-Synthetic Modification of Metal-Organic Frameworks (MOFs) and Polyhedra (MOPs)." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/670090.
Full textEsta Tesis ha sido dedicada al diseño e implementación de nuevas técnicas de modificación post-sintética (PSM) aplicadas a material metalorgánicos, principalmente polímeros de coordinación (CPs), redes metalorgánicas (MOFs) y poliedros metalorgánicos (MOPS) , a fin de modificar sus propiedades fisicoquímicas a niveles inaccesibles a través de metodologías comunes de síntesis directa. La Tesis comienza ofreciendo una breve recapitulación bibliográfica del campo de los materiales metalorgánicos, desde sus inicios hasta su aplicación actual y perspectivas de futuro. Este capítulo engloba los conceptos más importantes sobre su síntesis y modificación post-sintética, tanto en sus nodos metálicos como en los ligandos orgánicos que construyen las redes; con un particular énfasis en las técnicas post-sintéticas desarrolladas hasta la fecha. Seguidamente, la Tesis es dividida en cuatro capítulos extra, donde cada uno de ellos se enfoca en un proceso de modificación post-sintética concreto. Inicialmente, la Tesis se centra en la modificación post-sintética de las subunidades metálicas de polímeros de coordinación basados en ligando macrocíclicos. La presencia de una fuente de iones metálicos quelatados dentro de la cavidad macrocíclicos los ligandos induce una transición de fase de monocristal monocristal en contacto con agua, obteniendo una distribución regular de subunidades; rueda de paletas (paddlewheel) bimetálica en la red. Esta transición de fase es seguida a través de difracción de monocristal, así como a través de técnicas de caracterización espectroscópicas y magnéticas. En el siguiente capítulo se postula una técnica de modificación post-sintética hasta ahora inexplorada en el campo de los materiales metalorgánicos. Gracias a su microporosidad intrínseca, los MOF pueden difundir gases altamente reactivos a través de su red, lo que puede inducir potencialmente una modificación post-sintética a través de reacciones sólido-gas en cuestión de minutos. Para probar esta hipótesis, un MOF decorado con funcionalidades olefina se hizo reaccionar difundiendo ozono a través de su red. El producto de reacción obtenido presenta clara evidencia de tener dentro de sus canales de reacción del esperado intermedio de reacción para la reacción de ozonólisis, teóricamente inestable. Este intermedio puede ser convertido en un paso posterior a grupos aldehído o ácido carboxílico de forma quimiselectiva. Todo el proceso es caracterizado por técnicas de resonancia magnética nuclear (RMN) y difracción de monocristal. Finalmente, el conocimiento adquirido en la modificación post-sintética de CPs y MOFs se traslada al campo de los materiales cero-dimensionales. Concretamente, esta Tesis demuestra cómo poliedros metalorgánicos (MOPS) de rodio pueden ser modificados en su periferia a través de química de coordinación y covalente, modificando así sus propiedades fisicoquímicas (solubilidad) sin afectar a su integridad estructural. Esta modificación post-sintética obra nuevos caminos hacia la explotación práctica de estos materiales, ya que debido a su estructura finita los MOPS pueden ser vistos como nanopartículas estequiométricamente funcionalizadas con solubilidad tuneable. Esta modificación post-sintética permite además introducido grupos funcionales en la periferia de los MOPS que no pueden ser incorporados en síntesis directa. Así, a través de un proceso en dos pasos, MOPS con 24 grupos amino o ácido carboxílico son sintetizados. Ambos grupos presentan objetivamente una de las químicas más ricas en química covalente o de coordinación, respectivamente, lo que abre nuevas fronteras para la aplicación de estas nanoplataformas.
The disserted Ph.D. Thesis was dedicated to the design and implementation of new post-synthetic modification (PSM) techniques to porous metal-organic materials, namely Coordination Polymers (CPs), Metal-Organic Frameworks (MOFs) and Metal-Organic Polyhedra (MOPs), in order to modify their physicochemical properties to inaccessible levels by common direct synthesis methodologies. The Thesis starts offering a brief bibliographic review of the evolution of metal-organic materials field, from their beginnings up to their actual applications and future perspectives. This chapter presents the most relevant concepts in their synthesis and their potential PSM, both in the metallic nodes or in the organic linkers that assemble the framework; with particular emphasis on the post-synthetic methodologies exploited up to date. Next, the Thesis is divided in four extra Chapters, each of them corresponding to a specific post-synthetic modification process. Initially, the Thesis focuses on the post-synthetic modification of the metallic subunits of macrocycle-based CPs. The presence of a second source of metal ions quelated inside the macrocyclic cavity induces a single-crystal-to-single-crystal phase transition in contact with water, obtaining a regular distribution of bimetallic paddlewheel subunits within the framework. Such transition was studied by single-crystal X-Ray diffraction techniques, as well as spectroscopic and magnetic characterization techniques. Next, an unexplored pathway for the PSM of MOFs is postulated. Thanks to their nanoporous structure, MOFs can diffuse highly-reactive gases through their framework in order to modify their structure through solid-gas reactions in a matter of minutes. To this end, an olefin-tagged MOF is post-synthetically modified by diffusing ozone gas through the porous channels of the material. The as-obtained reaction intermediate can be chemoselectively converted to either aldehyde or carboxylic acid groups without affecting the crystalline integrity of the material. The whole two-step process is characterized by Nuclear Magnetic Resonance (NMR) techniques, as well as single-crystal X-Ray diffraction. Afterwards, the post-synthetic modification of metal-organic architectures is extended to zero-dimensional materials. Concretely, it is demonstrated how the surface functionalization of Rhodium (II)-based Metal-Organic Polyhedra, both through coordination or covalent chemistries, is able to tune their solubility within a wide range of solvents, without affecting the scaffold’s integrity. This post-modification opens up new pathways for exploiting these materials. Because of their finite structure, MOPs can be seen as stoichiometrically-functionalized nanoparticles with tunable solubility. Such acquired knowledge is then applied to expand the available roster of Rh(II)-based MOPs. Through a two-step protection/deprotection strategy, two unprecedented Rh-MOPs with 24 free carboxylate or amino groups on their periphery are synthesized, unobtainable by direct synthesis methodologies. Both groups arguably present one of the richest chemistries in coordination and covalent chemistry, respectively, thus opening new pathways and frontiers towards the application of these materials.
Searle, R. J. "Modification of the mechanical properties of synthetic hydrogels by various techniques." Thesis, London Metropolitan University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254981.
Full textAzzawi, Itimad Dawood Jumaah. "Application of synthetic jet actuators for modification of separated boundary layers." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/15542/.
Full textThompson, Kimberlee Fay. "Modification of polymeric substrates using surface grafted nanoscaffolds." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-05162005-165302/.
Full textCarter, W. Brent, Committee Member ; Cook, Fred, Committee Member ; Griffin, Anselm, Committee Member ; Michielsen, Stephen, Committee Chair ; Beckham, Haskell, Committee Member ; Bottomley, Lawrence, Committee Member.
Crawford, Lisa Ann. "Investigating Chemical Modifications in a Complex Proteome." Thesis, Boston College, 2017. http://hdl.handle.net/2345/bc-ir:107651.
Full textThesis advisor: Jianmin Gao
Proteins are composed of the 20 naturally occurring amino acids and are further modified by a variety of post-translational modifications (PTMS). Naturally occurring amino acids are diverse in structure and function. Catalytic amino acids, or nucleophilic amino acids, are of particular interest because of their contribution to chemical transformations in the cell. Synthetic covalent modification is a means to further functionalize or diversify proteins. These modifications, or enhancements, allow for improved understanding of protein structure, function and activity. For instance, isotope labeling of amino acid side chains in NMR studies enable investigators to study protein dynamics upon substrate or ligand binding. Fluorescence labeling is particularly useful to investigate protein cellular localization. Covalent modification is a useful tool to investigate the relative level of activity for protein known to be regulated by PTMs. An important feature of covalent modification reactions is site specificity, as this dictates the location, number of modifications, and protein targets. Tyrosine is of particular interest because it is both nucleophilic and aromatic. These characteristics contribute to the existence of tyrosine residues in both the protein surface and hydrophobic cores. Tyrosine is incorporated into proteins at a relatively low frequency. Unlike lysine, which is ubiquitous on protein surfaces, the low number of potential sites for general tyrosine modifications makes it an attractive site for surface bioconjugation modifications. A low number of surface modifications is less likely to perturb native protein function. Bioconjugation reactions give access to functionalizing the surface of proteins with moieties such as fluorophores, PEG, peptides, or drugs. Tyrosine is an attractive target for modifications because it is found in the active sites of a variety of enzymes such as sialidases, glutathione-S transferases, corticosteroid 11-beta-dehydrogensase, DNA topoisomerase, and ferredoxin-NADP+ reductase. Provided here is a survey of the known non-selective and selective synthetic chemical modification reactions for tyrosine. To investigate nucleophilic amino acids, Activity Based Protein Profiling (ABPP) may be implemented to investigate the role of these residues. ABPP utilizes small molecule covalent probes as a tool to selectively target enzymes in their active state. To investigate a protein of interest (POI) (or class of proteins) by ABPP, it is necessary to use a small molecule covalent probe that selectively reacts with the POI over other proteins within the proteome. Due to this requirement, it is necessary to expand the current ABPP probe toolbox to increase the coverage of what proteins in the proteome may be studied. Inspired by findings in the literature, our lab sought to explore the utility of various aryl halides for implementation in ABPP probes to overcome this limitation. This study revealed dichlorotriazine as a biologically relevant and reactive electrophile. A focus was placed on a dichlorotriazine containing probe library (LAS1-LAS20). LAS17 was discovered to be a potent and selective inhibitor of human glutathione S-transferase pi (GSTP1). Further studies revealed GSTP1 as a novel therapeutic target for the treatment of triple negative breast cancer. Other studies revealed several members of the dichlorotriazine library were found to covalently modify purified recombinant human aldolase A (ALDOA) in the presence of a complex cellular background. Additionally, LAS9 was identified as an inhibitor of ALDOA retro aldol condensation activity in vitro. Lastly, the final chapter highlights two collaborations in which tandem mass spectrometry experiments aid in the characterization of experimental data. In the first collaboration, a quantitative cysteine reactivity profiling method was used to characterize the selectivity of a cysteine reactive covalent NRF2-inducing small molecule, MIND4-17. In the second collaboration, analysis of tryptic mass spectrometry data enabled high resolution characterization of peptide sequencing for superfolder green fluorescent protein (sfGFP) expressed from observed internal nonsense suppression. Identification of the misincorporated amino acid facilitated the elucidation of the cross-talk mechanism
Thesis (PhD) — Boston College, 2017
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
Runacres, Selwyn Mark. "The modification of natural occuring polymers for the removal of heavy metal ions." Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340955.
Full textMatsunaga, Masashi. "Development of physico-chemical pretreatments to enhance the biodegradability of synthetic low-density polyethylene film." Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343487.
Full textMunedzimwe, Tatenda Carol. "The isolation, quantification and synthetic modification of antiplasmodial natural products from sargassum heterophyllum." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1018252.
Full textDas, Lopamudra. "Surface Modification of Synthetic and Natural Polymers using Deep Uv (172 Nm) Irradiation." W&M ScholarWorks, 2017. https://scholarworks.wm.edu/etd/1530192366.
Full textShimko, John C. "Synthetic Tools for the Preparation of Modified Histones." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322664987.
Full textHonohan, Andrew M. "The interaction of synthetic jets with cross flow and the modification of aerodynamic surfaces." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/20836.
Full textLim, Zi-Yian. "Preparation, modification, and characterisation of Yolk-shell structure based catalysts for synthetic gas production." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41666/.
Full textIssa, Hussein. "Toolbox of post-synthetic mordenite modification strategies : Impact on textural, acidic, and catalytic properties." Thesis, Poitiers, 2019. http://www.theses.fr/2019POIT2268.
Full textZeolites are extremely useful heterogeneous catalysts and find widespread industrial applications. Yet, their extended microporous system leads to rather low efficiency factors and favors the development of secondary reactions that can substantially reduce catalytic selectivity and stability. Hierarchization of zeolites has been proposed as strategy for efficiently reducing the diffusion path length, hence allowing to increase the efficiency factor in catalysis. Among the plethora of disclosed hierarchization strategies, the real impact of the structural and chemical modifications on the catalytic key parameters is oftentimes neglected. The aim of this contribution is thus to shed light on the effective quality of zeolite hierarchization through the rational study of structure/catalytic property dependency. Our study focused on mordenite, as this zeolite is of particular importance due to its strong acidity and monodimensional channel system, which explains why mordenite is industrially extensively employed in a variety of processes including alkylations, isomerizations, dehydrations and aminations. A toolbox of post-synthetic hierarchization strategies on aluminium rich and poor mordenites have been developed based on basic treatments assisted by CTAB and pyridine at various temperatures (in conventional and microwave heating) and acid HF etching in aqueous and organic medium. A systematic study of over 50 post-synthetically modified mordenites was conducted, which allowed us to assess the impact of each of the hierarchization strategy on textural, morphological, chemical and catalytic properties. Major correlations between structural features and catalytic activity, selectivity and stability in n-hexane cracking and toluene disproportionation were deduced. A roadmap on the quality of each hierarchization strategy was thus developed
Albrecht, Delphine. "Etude des mutants synthétiques létaux avec l'AICAR chez la levure et conservation chez l'Homme." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0134/document.
Full textIdentifying synthetic lethal interactions has emerged as a promising new therapeutic approach that aims to directly target the cancer cells. Here, we used the yeast Saccharomyces cerevisiae as a simple eukaryotic model to screen for mutations resulting in a synthetic lethality with 5-Amino-4-ImidazoleCArboxamide Ribonucleoside (AICAR) treatment. Indeed, AICAR has been reported to specifically inhibit the proliferation of multiple cancer cell lines. Here, we found that loss of two several histone modifying enzymes, including Bre1 (histone H2B ubiquitination) and Set1 (histone H3 lysine 4methylation), greatly enhanced AICAR inhibitory effects on growth. Our results point to AICAR causing a significant accumulation of G1 cells due to its impact on Cln3 subcellular localization, whilebre1 or set1 deletion impacts on the two other G1 cyclins, by affecting CLN1 and CLN2 expression .As a consequence, AICAR and bre1/set1 deletions jointly affect all three G1 cyclins, leading to a condition that is known to result in synthetic lethality. Most importantly, these chemo-genetic synthetic interactions were conserved in human HCT116 cells. Knock-down of RNF40, ASH2L orKMT2D induced a highly significant increased sensitivity to AICAR. As KMT2D is mutated at high frequency in a variety of cancers, this synthetic lethal interaction has an interesting therapeutic potential
Chalker, Justin M. "Reaction engineering for protein modification : tools for chemistry and biology." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:52d92917-5c7f-4223-b554-2e1b4fc0b2ea.
Full textChooi, Kok Phin. "Synthetic phosphorylation of kinases for functional studies in vitro." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:2adc517a-2876-4a0b-8ead-e9bf164ebc6f.
Full textRideau, Fabien. "Clonage et modification du génome de Mycoplasma hominis dans la levure Saccharomyces cerevisiae." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0227/document.
Full textMycoplasma hominis is an opportunistic human pathogen responsible for genital and neonatal infections. Genetically modifying this bacterium is necessary to understand the virulence and infection mechanisms of this pathogen. There is currently no effective molecular tool to engineer the genome of this bacterium, limiting research on its pathogenicity and its peculiar metabolism based on arginine.New technologies have recently emerged in the field of Synthetic Biology (BS), offering new perspectives for the study of mycoplasmas by allowing large scale genome modifications and the production of mutant strains. Work at the J. Craig Venter Institute (JCVI, USA) has shown that the genome of related mycoplasmas can be cloned and manipulated in yeast before being transplanted into a recipient cell. The yeast serves as a temporary host to modify the genome of the bacterium. This innovative approach opens many perspectives in the development of functional genomics in mycoplasmas for which there are few effective genetic tools. The goal of this thesis was to adapt a number of BS tools to M. hominis for the first time, in order to create mutants deficient for a given function. To achieve this goal, the genome of the M. hominis type strain PG21 (665 kb) was cloned into the yeast Saccharomyces cerevisiae by Transformation-Associated Recombination cloning (TAR-cloning). Two yeast clones (B3-2 and B3-4) possessing the complete genome of M. hominis were validated by simplex PCR, multiplex PCR and Pulsed Field Gel Electrophoresis (PFGE) analyses. These yeast clones were then propagated in a selective medium for 180 generations (30 passages) to evaluate the stability of the bacterial genome in its host. This experiment showed that (i) the size of the genome of M. hominis did not change during the first passages, it decreased progressively from the tenth passage (≈60 generations), and (ii) the enriched genome areas in repeated sequence were preferentially lost. Thus, the genome of M. hominis was modified in the B3-4 clone at early passages using the Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 (CRISPR/Cas9) technology. Yeast clones with a complete M. hominis PG21 genome with a deleted vaa gene, encoding a major adhesion protein, were produced using this approach. The final step of this approach was to transplant the modified genome into a recipient cell of M. hominis or Mycoplasma arthritidis, the species phylogenetically closest to M. hominis. As no M. hominis transformation protocol was available at the beginning of our work, this step constituted a major obstacle in the implementation of BS tools in this species. This barrier has been partially lifted since a method of transformation of M. hominis based on polyethylene glycol (PEG) and involving the plasposon pMT85 (plasmid carrying a transposon conferring resistance to tetracycline) has been developed in the laboratory. This transformation technique, developed for the reference strain M. hominis M132 (745 kb) still remains not very efficient; it is nevertheless reproducible and allowed to obtain M. hominis mutants of interest. The Mhom132_2390 gene, encoding the precursor of the P75 protein, a putative adhesin of M. hominis, was effectively mutated in transformant No. 28-2. Complete genome sequencing of other transformants revealed the insertion of multiple copies of the transposon and the presence of duplication and inversion of large DNA fragments within at least two M. hominis genomes.In conclusion, this data has opened the way for the development and transposition of existing genetic modification approaches to M. hominis, previously considered as a genetically intractable bacterium
Mitchell, Laura. "Metal organic frameworks as Lewis acid catalysts." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6392.
Full textDempster, Nicola M. "Synthetic modification and characterisation of poly(styrene-co-divinylbenzene) resins and their possible application in environmental analysis." Thesis, Liverpool John Moores University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590096.
Full textThenna, Hewa Kosala R. S. "Applications Focused Synthetic Modification on Photoremovable Protecting Groups (PRPG) & Photochemical Analysis on Organic Azides and Isoxazoles." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511858669354976.
Full textBellancini, Michele. "Engineering the synthesis of lantibiotics in e. Coli by combining the cynnamicin and nisin modification systems." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8625/.
Full textMohamed, Nasser Hassan [Verfasser], Jochen Stefan [Akademischer Betreuer] Gutmann, and Mathias [Akademischer Betreuer] Ulbricht. "Surface Modification of Synthetic Fibers for Antibacterial Applications / Nasser Hassan Mohamed. Gutachter: Mathias Ulbricht. Betreuer: Jochen Stefan Gutmann." Duisburg, 2013. http://d-nb.info/1030475466/34.
Full textKnaggs, Jonathan David. "The modulation of Transient Receptor Potential A1 channel by natural and novel semi-synthetic compounds via non-covalent modification." Thesis, University of Hull, 2016. http://hydra.hull.ac.uk/resources/hull:15136.
Full textCatli, Candan. "Novel synthetic approaches for fabrication of polymer brushes on gold surfaces via Raft polymerization: A new era for gold modification." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E353-2.
Full textÅgren, Jonas. "Regional Geoid Determination Methods for the Era of Satellite Gravimetry : Numerical Investigations Using Synthetic Earth Gravity Models." Doctoral thesis, KTH, Infrastructure, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-55.
Full textIt is the purpose of this thesis to investigate different regional geoid determination methods with respect to their feasibility for use with a future GOCE satellite-only Earth Gravity Model (EGM). This includes investigations of various techniques, which involve different approximations, as well as the expected accuracy. Many, but not all, of these tasks are tested by means of Synthetic Earth Gravity Models (SEGMs). The study is limited to remove-compute-restore methods using Helmert condensation and to Sjöberg's combined approach (method with additive corrections).
First, a number of modifications of Stokes' formula are tested with respect to their compatibility with a GOCE EGM having negligible commission error. It is concluded that the least squares modification method should be preferred.
Next, two new point-mass SEGMs are constructed in such a way that the resulting models have degree variances representative for the full and topographically reduced gravity fields, respectively. These SEGMs are then used to test different methods for modified Stokes' integration and downward continuation. It is concluded that the combined method requires dense observations, obtained from the given surface anomalies by interpolation using a reduction for all known density anomalies, most notably the topography. Examples of other conclusions are that the downward continuation method of Sjöberg (2003a) performs well numerically.
To be able to test topographic corrections, another SEGM is constructed starting from the reduced point-mass model, to which the topography, bathymetry and isostatic compensation are added. This model, which is called the Nordic SEGM, is then applied to test one strict and one more approximate approach to Helmert's condensation. One conclusion here is that Helmert's 1st method with the condensation layer 21 km below sea level should be preferred to Helmert's 2nd condensation strategy.
The thesis ends with a number of investigations of Sjöberg's combined approach to geoid determination, which include tests using the Nordic SEGM. It is concluded that the method works well in practice for a region like Scandinavia. It is finally shown how the combined strategy may preferably be used to estimate height anomalies directly.
Reyna, González Emmanuel [Verfasser], and Elke [Akademischer Betreuer] Dittmann. "Engineering of the microviridin post-translational modification enzymes for the production of synthetic protease inhibitors / Emmanuel Reyna González ; Betreuer: Elke Dittmann-Thünemann." Potsdam : Universität Potsdam, 2017. http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-406979.
Full textHughes, David. "The local free volume and other properties of synthetic and biopolymers : the effect of chemical and modification, matrix composition and environmental conditions." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702746.
Full textReyna, González Emmanuel [Verfasser], and Elke [Akademischer Betreuer] Dittmann-Thünemann. "Engineering of the microviridin post-translational modification enzymes for the production of synthetic protease inhibitors / Emmanuel Reyna González ; Betreuer: Elke Dittmann-Thünemann." Potsdam : Universität Potsdam, 2017. http://d-nb.info/1218403276/34.
Full textWang, Zhengbang [Verfasser], and P. [Akademischer Betreuer] Roesky. "Liquid-Phase Epitaxial Growth of Highly Oriented and Crystalline MOF Thin Films: Post-Synthetic Modification and Different Applications / Zhengbang Wang. Betreuer: P. Roesky." Karlsruhe : KIT-Bibliothek, 2015. http://d-nb.info/1067497005/34.
Full textEpley, Charity Cherie. "Developing Photo-responsive Metal-Organic Frameworks towards Controlled Drug Delivery." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78346.
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Wyss, Sarah Christine. "Design of a Cross-Domain Quorum Sensing Pathway for Algae Biofuel Applications." Ohio University Honors Tutorial College / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1367239424.
Full textIslamoglu, Timur. "SYSTEMATIC POSTSYNTHETIC MODIFICATION OF NANOPOROUS ORGANIC FRAMEWORKS AND THEIR PERFORMANCE EVALUATION FOR SELECTIVE CO2 CAPTURE." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4264.
Full textSomero, John Ryan. "Structure and Persistence of Surface Ship Wakes." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/101989.
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It has long been known that ship wakes are observable by synthetic aperture radar. However, incomplete physical understanding has prevented the development of simulation tools that can predict both the structure and persistence of wakes in the ocean environment, which is critical to understanding both the design and operation of maritime remote sensors as well as providing tactically relevant operational guidance and awareness of the maritime domain. It is the focus of this work to develop an end-to-end multi-scale modeling-and simulation methodology that captures the known physics between the source of disturbance and the sensor. This includes turbulent hydrodynamics, free-surface effects, environmental forcing, generation of surface currents and redistribution of surface-active substances, surface-roughness modification, and simulation of the signature from the ocean surface. The end-to-end methodology is based upon several customized computational fluid dynamics solvers and empirical models. The unsteady Reynolds-averaged Navier-Stokes equations, including models to account for environmental effects and near-surface turbulence, are solved at full-scale on domains that extend tens of kilometers behind the ship. A parametric study is undertaken to explore the effects of ship heading, ship propulsion, ocean-wave amplitude and wavelength, and the relative importance of environmental forcing vs. near-surface turbulence on the generation of surface currents that are transverse to the wake centerline. Due to the environmental forcing, the structure of the persistent wake is shown to be a function of the relative angle between the ambient long-wavelength swell and the ship heading. Ships operating in head seas observe 1-3 streaks, while ships operating in following seas observe 2 symmetric streaks. Ships operating in calm seas generate similar wakes to those in following seas, but with reduced wake width and persistence. In addition to the structure of the persistent wake, the far wake is shown to be dominated by ship-induced turbulence and surface-current gradients generating a wide center wake. The redistribution of surface films by surface currents is simulated using a scalar-transport model on the ocean surface. Simulation of surface-roughness modification is accomplished by solving a wave-action-balance model which accounts for the relative change in the ambient surface profile by the surface currents and the damping-effects of surface-active substances and turbulence. Simulated returns from synthetic aperture radar are generated with two methods implemented. The first method generates a perfect SAR image where the instrument and platform based errors are neglected, but the impact of a randomized ocean field on the radar cross section is considered. The second method simulates the full SAR process including signal detection and processing. Comparisons are made to full-scale field experiments with good agreement between the structure of the persistent wake and observed SAR imagery.
Joly, Jean-Patrick. "Conception, synthèse et étude de nouvelles molécules bioactives. Propriétés antivirales et antimélanome." Thesis, Nice, 2013. http://www.theses.fr/2013NICE4129.
Full textDespite significant progress made in recent years, the fight against viral infections (AIDS, Hepatitis, etc.) and cancer remains a global health problem. This brief summary underlines the need for new compounds in order to overcome the limitations of currently available drugs. To this end, the main objective of this thesis is to address these issues by the investigation of three major research projects. We first developed new RNA ligands that selectively bind to RNA secondary structures such as the stem-loop or the stem-bulge of HIV-1 TAR RNA. These ligands interact with RNA thanks to the presence of two RNA binding domains acting in a cooperative manner: (i) a modified nucleobase that can specifically recognize an RNA base pair and (ii) basic amino acids that interact with strong affinity with surrounding free RNA nucleobases. These two patterns are connected by an aliphatic matrix (non-nucleoside ligands) or a 2-desoxyribose matrix (nucleoside-based ligands). Biophysical and biological studies were conducted in collaboration with the team of Dr. L. Briant (CEAPBS, UMR5236-CNRS) in order to study their antiviral activity and their mode of action. We next developed new bioactive molecules featuring a thiazole benzenesulfonamide scaffold to target melanoma cells resistant to B-Raf inhibitors. The modular synthesis of a large number of analogs allowed us to establish the structure/activity relationships, in collaboration with the team of Dr. S. Rocchi (C3M, INSERM U895). Finally, we developed a straightforward and convenient strategy for post-synthetic modification of oligonucleotides at the anomeric position using click chemistry
Muwonge, Abubaker. "Detection Of Genetically Modified Potatoes By The Polymerase Chain Reaction." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605783/index.pdf.
Full textMonneau, Yoan. "Etude des modifications post-traductionnelles des histones : l’analyse structuro-fonctionnelle d'une peptidyl-prolyl isomérase et la production semi-synthétique d’une protéine acétylée." Thesis, Bordeaux 2, 2011. http://www.theses.fr/2011BOR21900/document.
Full textThe structural unit of chromatin, the nucleosome, is composed of double-stranded DNA wrapped around a histone octamer and is subject to a plethora of post-translational modifications. The biological consequences of peptidyl-prolyl isomerization and lysine acetylation were investigated at atomic scale through analysis of in vitro reconstituted systems by NMR. Peptidyl-prolyl bonds of histone H3 N-terminal domain are substrates in vitro of an isomerase from S. cerevisiae named Fpr4p, which underlies transcriptional control dependent on its catalytic activity. The solution structure of the catalytic domain of Fpr4p was calculated based on restraints from NMR spectroscopy, and reveals a canonical catalytic domain belonging to the FK506-binding protein (FKBP) family. Based on primary sequence analysis and NMR experiments, a preliminary structural model of full length Fpr4p is also presented. Functional analyses were performed with three decapeptides designed from the primary sequence from the N-terminal tail of S. cerevisiae histone H3. All three constitute substrates of Fpr4p, with equivalent catalysis observed for Pro16 and Pro30. The equilibrium proportion of the cis-proline conformer has been determined for all three decapeptides, and these populations are unaffected by Fpr4p catalytic activity. Structural ensembles of the substrates with proline in the trans conformation were determined by using NMR spectroscopy, and will be subsequently used for in silico molecular docking onto Fpr4p. To study a second form of histone regulation, a semi-synthetic method to produce acetylated protein was developed. The protocol relies on the site-specific mutation of lysine to cysteine in recombinant proteins followed by controlled alkylation thanks to nucleophilicity of the introduced thiol. The production of the required alkylation reagent is easy, quick, and suitable for biology laboratory and allows diverse isotopic labeling within the acetyl group. Alkylation of folded proteins has also been achieved in native conditions. As one target of acetylation in vivo, the histone H2A-H2B dimer is an intermediate of nucleosome assembly and was reconstituted in vitro. Chemical shift values of the N- and C-terminal domains of H2A are in agreement with an intrinsically disordered state although they display differences in dynamic mobility
Calzada, Defez Àngel. "Conveying expressivity and vocal effort transformation in synthetic speech with Harmonic plus Noise Models." Doctoral thesis, Universitat Ramon Llull, 2016. http://hdl.handle.net/10803/360587.
Full textEsta tesis se llevó a cabo en el Grup en Tecnologies Mèdia de la Escuela de Ingeniería y Arquitectura la Salle. El grupo lleva una larga trayectoria dentro del campo de la síntesis de voz y cuenta con su propio sistema de síntesis por concatenación de unidades (US-TTS). El sistema permite sintetizar múltiples estilos expresivos mediante el uso de corpus específicos para cada estilo expresivo. De este modo, para realizar una síntesis agresiva, el sistema usa el corpus de este estilo, y para un estilo sensual, usa otro corpus específico para ese estilo. La presente tesis aborda el problema con un enfoque distinto proponiendo cambios en el esquema del sistema con el fin de mejorar la flexibilidad para sintetizar múltiples estilos expresivos a partir de un único corpus de estilo de habla neutro. El planteamiento seguido en esta tesis esta basado en el uso de técnicas de procesamiento de señales (DSP) para llevar a cabo modificaciones del señal de voz para que este exprese el estilo de habla deseado. Para llevar acabo las modificaciones de la señal de voz se han usado los modelos harmónico más ruido (HNM) por su flexibilidad para efectuar modificaciones de señales. La cualidad de la voz (VoQ) juega un papel importante en diferentes estilos expresivos. Por ello se exploró la síntesis expresiva basada en modificaciones de parámetros de bajo nivel de la VoQ. Durante este estudio se detectaron diferentes problemas que dieron pié a los objetivos planteados en esta tesis, entre ellos el encontrar un único parámetro con fuerte influencia en la expresividad. El parámetro seleccionado fue el esfuerzo vocal (VE) por su importante papel a la hora de expresar diferentes emociones. Las primeras pruebas se realizaron con el fin de transferir el VE entre dos realizaciones con diferente grado de VE de la misma palabra usando una metodología basada en un proceso filtrado de pre-émfasis adaptativo con coeficientes de predicción lineales (APLP). Esta primera aproximación logró transferir el nivel de VE entre dos realizaciones de la misma palabra, sin embargo el proceso presentaba limitaciones para generar niveles de esfuerzo vocal intermedios. A fin de mejorar la flexibilidad y el control del sistema para expresar diferentes niveles de VE, se planteó un nuevo modelo de VE basado en polinomios lineales. Este modelo permitió transferir el VE entre dos palabras diferentes e incluso generar nuevos niveles no presentes en el corpus usado para la síntesis. Esta flexibilidad está alineada con el objetivo general de esta tesis de permitir a un sistema US-TTS expresar múltiples estilos de habla expresivos a partir de un único corpus de estilo neutro. Además, la metodología propuesta incorpora un parámetro que permite de forma sencilla controlar el nivel de VE expresado en la voz sintetizada. Esto abre la posibilidad de controlar fácilmente el proceso de síntesis tal y como se hizo en el proyecto CreaVeu usando interfaces simples e intuitivas, también realizado dentro del grupo GTM. Esta memoria concluye con una revisión del trabajo realizado en esta tesis y con una propuesta de modificación de un esquema de US-TTS para expresar diferentes niveles de VE a partir de un único corpus neutro.
This thesis was conducted in the Grup en Tecnologies M`edia (GTM) from Escola d’Enginyeria i Arquitectura la Salle. The group has a long trajectory in the speech synthesis field and has developed their own Unit-Selection Text-To-Speech (US-TTS) which is able to convey multiple expressive styles using multiple expressive corpora, one for each expressive style. Thus, in order to convey aggressive speech, the US-TTS uses an aggressive corpus, whereas for a sensual speech style, the system uses a sensual corpus. Unlike that approach, this dissertation aims to present a new schema for enhancing the flexibility of the US-TTS system for performing multiple expressive styles using a single neutral corpus. The approach followed in this dissertation is based on applying Digital Signal Processing (DSP) techniques for carrying out speech modifications in order to synthesize the desired expressive style. For conducting the speech modifications the Harmonics plus Noise Model (HNM) was chosen for its flexibility in conducting signal modifications. Voice Quality (VoQ) has been proven to play an important role in different expressive styles. Thus, low-level VoQ acoustic parameters were explored for conveying multiple emotions. This raised several problems setting new objectives for the rest of the thesis, among them finding a single parameter with strong impact on the expressive style conveyed. Vocal Effort (VE) was selected for conducting expressive speech style modifications due to its salient role in expressive speech. The first approach working with VE was based on transferring VE between two parallel utterances based on the Adaptive Pre-emphasis Linear Prediction (APLP) technique. This approach allowed transferring VE but the model presented certain restrictions regarding its flexibility for generating new intermediate VE levels. Aiming to improve the flexibility and control of the conveyed VE, a new approach using polynomial model for modelling VE was presented. This model not only allowed transferring VE levels between two different utterances, but also allowed to generate other VE levels than those present in the speech corpus. This is aligned with the general goal of this thesis, allowing US-TTS systems to convey multiple expressive styles with a single neutral corpus. Moreover, the proposed methodology introduces a parameter for controlling the degree of VE in the synthesized speech signal. This opens new possibilities for controlling the synthesis process such as the one in the CreaVeu project using a simple and intuitive graphical interfaces, also conducted in the GTM group. The dissertation concludes with a review of the conducted work and a proposal for schema modifications within a US-TTS system for introducing the VE modification blocks designed in this dissertation.
Yildiz, Ceylan [Verfasser], and W. [Akademischer Betreuer] Kleist. "Post-synthetic modification of mixed-linker metal-organic frameworks for the design of heterogeneous single-site catalyst materials and their application in liquid phase oxidation reactions / Ceylan Yildiz ; Betreuer: W. Kleist." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1209199149/34.
Full textNouar, Farid. "Design, Synthesis and Post-Synthetic Modifications of Functional Metal-Organic Materials." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1725.
Full textCatli, Candan [Verfasser], Philipp [Akademischer Betreuer] Vana, Jörg [Gutachter] Enderlein, Konrad [Gutachter] Samwer, and Annette [Gutachter] Zippelius. "Novel synthetic approaches for fabrication of polymer brushes on gold surfaces via Raft polymerization: A new era for gold modification / Candan Catli ; Gutachter: Jörg Enderlein, Konrad Samwer, Annette Zippelius ; Betreuer: Philipp Vana." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://d-nb.info/1152437712/34.
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