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As the world pushes for ‘greener’ technologies and carbon neutrality, efforts have focused on creating novel ways to mitigate humankind’s carbon footprint. Carbon capture and storage (CCS) has become a prevalent technique that has proven to be an effective long-term method to safely relocate excess carbon dioxide (CO2) into subsurface formations. However, CCS is a newer technique which requires constant monitoring due to potential leakage pathways present in CO2 storage sites; therefore, a preventive approach to seal leakage pathways is recommended. This dissertation explores the potential of CO2-sensitive polyacrylamide (CO2-SPAM) as a novel sealing agent for enhanced oil recovery (EOR) and CCS applications. This manuscript explores the strength and weaknesses of various CO2-triggered chemicals and selects the appropriate fit for subsurface in-situ sealing. Relevant literature shows that CO2-SPAM can significantly reduce permeability in porous media. Additionally, organically cross-linked polyacrylamide-based gels, of which CO2-SPAM is one, are thermally stable, resistant to low pH levels, highly injectable, and widely used in various industrial processes. These characteristics make CO2-SPAM a suitable candidate for in-situ sealing. Further studies were performed to comprehend the chemical mechanism, rheological behavior, and injection effects of CO2-SPAM into subsurface formations. Firstly, past literature knowledge and organic chemistry principals were used to develop the complete chemical breakdown of CO2-SPAM gel’s synthesis. Secondly, the effect of salt and polyacrylamide (PAM) concentrations on gelation time, gel strength and viscosity were tested through qualitative (Sydansk gel strength coding system) and quantitative methods (rheometer measurement). The results showed that high salinities increase gelation time and decrease gel strength and viscosity, while high PAM concentrations do the opposite. Lastly, the effects on geomechanical stresses caused by CO2-SPAM injection into the subsurface are also addressed by using the image well method for pore pressure estimation, and frictional faulting theory. The final results determined that the injection of aqueous CO2-SPAM would induce seismicity in normal faulting zones dipping at a large array of angles in the plane of failure. These findings are significant as they determine the potential of induced seismicity in the area of CCS, which in this case was the Raton basin.

<p dir="ltr">Creating synthetic materials that mimic native tissue is an overarching goal in tissue engineering and regenerative medicine. It is essential to embed molecular-resolution chemical patterning into soft synthetic polymers to achieve this. Even though fundamental principles from surface science offer broad control over the position of even individual atoms on a pristine surface, this degree of control remains restricted to two-dimensional hard crystalline materials under particular environmental conditions that are incompatible with life. Therefore, developing strategies to translate these principles into soft, amorphous interfaces is challenging<i>. </i>This will lead to the development of <i>nanopatterned soft materials</i> that closely resemble native tissue. Popular approaches in materials science fail to produce such <i>high-resolution polymers</i>.</p><p dir="ltr">Hydrogels are soft, three-dimensional networks that can hold large amounts of an aqueous solvent while retaining their structure. These materials have applicability in contexts where polymer materials must interface with biology (e.g., drug delivery, biosensing, tissue engineering, and regenerative medicine) as one can easily tune their mechanical, chemical, and biological properties. However, the main limitation of these materials is that the hydrogel network is amorphous, with substantial variability in mesh size up to the micron-scale. This limits their application when highly structured interactions with biomolecules, typically at sub-10 nm scales, are required. This dissertation shows a strategy to generate 1 nm-wide ordered patterns of functional groups on polyacrylamide (PAAm) hydrogel surfaces. When 1 nm-wide linear patterns are transferred to PAAm, patterning specific biological polyelectrolyte interactions at the hydrogel surface is possible. This represents a first step towards developing robust methods for nanopattern hydrogels at the proposed resolution.</p><p dir="ltr">One last subject this thesis dissertation seeks to explore is the extension of chemical patterning to a dynamic range of scales to adapt this technological advancement to industrial setups. Enabling the practical applicability of nanopatterned soft materials in macroscopic contexts (e.g., synthetic tissue development, wearable electronics, etc). However, extending this degree of control to a high throughput process applicable to heterogeneous interfaces remains a challenge. We demonstrated a scalable inkjet printing method to produce functional hierarchical patterns on two-dimensional crystalline substrates, which can be transferred to hydrogels. Finally, we studied the specific biosensing capabilities of these micro-patterned surfaces.</p>

Made available in DSpace on 2014-12-17T15:41:48Z (GMT). No. of bitstreams: 1 Bruna Vital de Lima_DISSERT.pdf: 1526229 bytes, checksum: 072431027e1aefba9f0023f2f514ae5f (MD5) Previous issue date: 2010-02-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The hydrolysis reaction in alkaline conditions of the commercial polymer poly(acrylamide-co-metacrylate of 3,5,5-trimethyl-hexane) called HAPAM, containing 0.75 % of hydrophobic groups, was carried out in 0.1 M NaCl and 0.25M NaOH solutions, varying the temperature and reaction time. The polymers were characterized by 1H and 13C Nuclear Magnetic Resonance (NMR), Elemental Analysis and Size Exclusion Chromatography (SEC). The values of the hydrolysis degree were obtained by 13C NMR. The viscosity of HAPAM and HAPAM-10N-R solutions was evaluated as a function of shear rate, ionic strength and temperature. At high polymer concentration (Cp), the viscosity of HAPAM solutions increased with the ionic strength and decreased with the temperature. The viscosity of HAPAM-10N-R solutions increased significantly in distilled water, due to repulsions between the carboxylate groups. At high Cp, with the increase of ionic strength and temperature, occurred a decrease of viscosity, due to mainly the high hydrolysis degree and the low amount of hydrophobic groups. These results indicated that the studied polymers have properties more suitable for the application in Enhanced Oil Recovery (EOR) in low salinity and moderate temperature reservoirs / A rea??o de hidr?lise em meio alcalino do pol?mero comercial poli(acrilamida-co-metacrilato de 3,5,5 trimetil-hexano) denominado HAPAM, contendo 0,75 % de grupos hidrof?bicos, foi realizada em solu??es de NaCl 0,1 M e NaOH 0,25 M, variando a temperatura e o tempo reacional. Os pol?meros foram caracterizados por Resson?ncia Magn?tica Nuclear (RMN) de 1H e 13C, An?lise Elementar e Cromatografia de Exclus?o por Tamanho (SEC). Os valores do grau de hidr?lise foram obtidos por RMN 13C. A viscosidade das solu??es de HAPAM e HAPAM-10N-R foi avaliada em fun??o da taxa de cisalhamento, for?a i?nica e temperatura. ? alta concentra??o polim?rica (Cp), a viscosidade das solu??es de HAPAM aumentou com a for?a i?nica e diminuiu com o aumento da temperatura. A viscosidade das solu??es de HAPAM-10N-R aumentou significantemente em ?gua destilada, devido ?s repuls?es entre os grupos carboxilato. ? alta Cp, com o aumento da for?a i?nica e da temperatura ocorreu uma diminui??o da viscosidade, devido, principalmente, ao alto grau de hidr?lise e ? baixa quantidade de grupos hidrof?bicos. Estes resultados indicaram que os pol?meros estudados apresentam propriedades mais adequadas para aplica??o na recupera??o avan?ada de petr?leo (EOR) em reservat?rios de baixa salinidade e temperatura moderada

Η μεσογειακή μύγα αποτελεί το κύριο παράσιτο πολλών καλλιεργούμενων φρούτων προκαλώντας ετησίως μεγάλες καταστροφές σε γεωργικές καλλιέργειες. Η μελέτη του εντόμου τόσο σε γενετικό όσο και σε πληθυσμιακό επίπεδο μπορεί να συμβάλλει σημαντικά στην ανάπτυξη ή και τη βελτίωση αποτελεσματικών και φιλικών προς το περιβάλλον μεθόδων ελέγχου. Οι μικροδορυφόροι είναι απλές επαναλήψεις ενός νουκλεοτιδικού μοτίβου που αποτελείται 1-6 ζεύγη βάσεων. Αποτελούν πολύ χρήσιμους γενετικούς δείκτες διότι είναι άφθονοι και διάσπαρτοι στο γονιδίωμα των ευκαρυωτκών οργανισμών. Επιπλέον είναι υψηλά πολυμορφικοί, κληρονομούνται ως συνυπερέχοντες Μεντελικοί δείκτες και αναλύονται εύκολα μέσω PCR, χαρακτηριστικά που τους καθιστούν πολύτιμα εργαλεία για πληθυσμιακές και εξελικτικές μελέτες. Από τους μικροδορυφορικούς δείκτες που αναπτύχθηκαν στο εργαστήριό μας, επιλέχθηκαν 10 με βάση το βαθμό πολυμορφισμού που έδειξαν σε εργαστηριακά στελέχη. Οι δείκτες αυτοί χρησιμοποιήθηκαν στην ανάλυση 481 ενηλίκων ατόμων που προέρχονταν από 19 διαφορετικά δείγματα φρούτων που συλλέχθηκαν από εννέα διαφορετικές περιοχές της Δυτικής Ελλάδας και της Βόρειας Πελλοπονήσου. Η γενοτυπική ανάλυση πραγματοποιήθηκε με ηλεκτροφόρηση των προϊόντων της PCR για κάθε γενετικό δείκτη σε πήκτωμα πολυακρυλαμιδίου και επακόλουθη αυτοραδιογραφία. Η στατιστική επεξεργασία των αποτελεσμάτων, με τη βοήθεια υπολογιστικών προγραμμάτων αποκάλυψε σημαντική γενετική διαφοροποίηση μεταξύ των δειγμάτων, που αποδίδεται εκτός των άλλων παραγόντων (κλιματολογικές συνθήκες, γεωγραφική προέλευση) στο είδος του ξενιστή. / C. capitata, is the main pest of many cultivable fruits and responsible for a significant loss in annual products, resulting in great economic damage. Studies on the genetic and population analysis will make a contribution towards the development or the improvement of environmental friendly control methods. Microsatellites are tandem simple sequence repeats of short (1-6) nucleotide motifs. They are very important genetic markers because they are dispersed and abundant in most eukaryotic genomes. They are highly polymorphic, inherited as co-dominant Mendelian markers and easily scored by PCR. Consequently, they have become one of the most popular molecular markers with application in many genetic studies, including genetic analysis of natural populations and evolutionary studies. From the available microsatellites in our laboratory, were selected ten (10), based on their polymorphism in laboratory strains. They were used for the screening of 481 adult flies in the medfly, collected from nineteen (19) different samples of fruits from nine (9) different areas in west Greece and north Peloponnesus. Analysis of genotype composition in the samples was achieved by polyacrylamide electrophoresis of the PCR products, for every genetic marker and then autoradiography. The statistic analysis of our results using software programs, revealed an important genetic differentiation in samples. Except for many factors (climatic conditions, geographic origin), the host origin will be responsible for this genetic differentiation.

Le but de ma thèse a été de concevoir des matériaux chimio-mécano répondants, des matériaux capables de permettre une transformation chimique réversible lorsqu’ils sont soumis à un stress mécanique. Tous les systèmes conçus ont été développés sur des substrats en silicone. Une première approche a consisté à créer des surfaces à sites cryptiques où une biotine est enfouie dans des brosses de chaines de poly(éthylène glycol). Le système streptavidine/biotine a été utilisé comme modèle. Ces surfaces sont anti-adsorbantes à la streptavidine sauf lorsqu’elles sont étirées à 50% où la biotine est reconnue mais les surfaces sont non réversibles. Dans une seconde approche, nous avons modifiés la surface du silicone par adsorption d’une multicouche de polyélectrolytes. Cette stratégie est basée sur la réticulation covalente du film par l’enzyme β-galactosidase modifiée. Nous sommes ainsi parvenus à créer une surface présentant une activité catalytique modulable par l’étirement mécanique, et ce, d’une façon partiellement réversible. Ce travail représente le premier exemple d’un système où une contrainte mécanique imposée à un matériau permet la déformation conformationnelle d’une enzyme et ainsi la diminution de l’activité catalytique. Dans une dernière approche, nous avons conçu un système mixte composé d’un substrat de silicone sur lequel un gel de polyacrylamide est greffée de façon covalente. Des enzymes ou des mécanophores pourront ainsi être inclus dans le réseau polymérique du gel de polyacrylamide et être étirés. Nous sommes parvenus à préparer de tels systèmes où l’hydrogel reste solidaire du film de silicone, sans apparition de craquelures jusqu’à 50%d’étirement. / The goal of my PhD was to develop new routes to design chemo-mechanoresponsive materials, materials that respond chemically to a mechanical stress, in a reversible way. All the systems designed during my PhD thesis were based on the functionalization of silicone sheets. First we created cryptic site surfaces by embedding biotin ligands into PEG brushes. The couple streptavidin/biotin was used as a model system. At rest, the surface so-prepared was antifouling and biotin ligands were specifically recognized by the streptavidin when the surface was stretched at 50%. Unfortunately, in this first approach, the mechanosensitive surface did not lead to a reversible process. In a second approach, we modified the silicone surface by using the polyelectrolyte multilayer (PEM) film deposition. This strategy was based on the covalent cross-linking of modified enzyme, the β-galactosidase, into the PEM. We succeeded in modulating the enzyme activity in the film under stretching and this approach appears as partially reversible under stretching/unstretching cycles. This work represents the first reported system where enzymatic activity can be modulated by stretching due to modulation of the enzyme conformation. In a last approach, we also designed a mixed system consisting of a silicone sheet onto which a polyacrylamide hydrogel is covalentlyattached with the goal to create a stretchable gel into which one can covalently attach enzymes or chemical mechanophores. These enzymes or mechanophores can thus be put under mechanical stress. We succeeded in creating a system that can be stretched up to 50% without detachment of the gel from the silicone and without inducing cracks in the gel.

The aim of this work was a research of the genetic variability of natural populations of Russian wheat aphid Diuraphis noxia (Aphididae) by means of microsatellite markers and markers for EPIC-PCR. First goal was to introduce the methods and optimise them for Diuraphis noxia. In the follow-up pilot study, specimens from 47 lines representing 12 populations from all over the world were analysed. Having used microsatellite markers, I proved expected variability among individual populations and within them. The highest genetic variability was detected between Chile and Algeria using markers for cytochrome C in EPIC-PCR. These findings can be used for further studies of the genetic variability of the aphid Diuraphis noxia.

Denna avhandling presenterar experimentella studier av polyelektrolytadsorption på motsatt laddade ytor, där substrat av både kiseloxid och blekt barrsulfatmassa har använts. Ett huvudsakligt syfte med denna forskning var att karaktärisera konformationen hos adsorberade skikt av katjonisk polyakrylamid (CPAM) i jämförelse med katjonisk dextran (Cdextran) och relatera denna information till inbindningskapaciteten av kolloidal kiselsyra. Ett andra syfte i denna avhandling var att studera kinetiken för sekventiell adsorption av polyamidamin epiklorhydrin (PAE) och karboxymetyl cellulosa (CMC) på massafibrer och att bestämma adsorptionsisotermer för deponering av polyelektrolyter skikt för skikt på massafibrer. Adsorptionen av CPAM på kiseloxidytor studeras med stagnationspunkts-reflektometri och kvartskristalls-mikrogravimetri för att bestämma adsorptionskinetiken och mättnadsadsorptionens beroende av polyelektrolytens laddningstäthet, pH och NaCl koncentration. Konformationen hos adsorberade skikt av CPAM och Cdextran bestämdes både före och efter sekundär tillsats av kolloidal kiselsyra (CS) och adsorptionen av CS kvantifierades också som funktion av yttäckningen av polyelektrolyt. Resultaten indikerar att laddningstätheten hos CPAM kontrollerar den adsorberade mängden på kiseloxidytor vid låga NaCl koncentrationer. Både adsorptionen av CPAM och Cdextran på kiseloxid visades vara effektiv i NaCl koncentrationer upp till 1 M, vilket indikerar ett signifikant bidrag av icke-jonisk interaktion mellan polyelektrolyterna och kiseloxid. Adsorptionen av CS var högre på föradsorberad CPAM än Cdextran. Konformationen hos de adsorberade skikten efter tillsats av CS sågs expandera signifikant för skikt baserade på CPAM medan skikt av Cdextran vid låga salthalter verkade återta sin konformation efter en temporär expansion. I den andra delen av avhandlingen studerades sekventiell adsorption av PAE och CMC på massafibrer. Adsorptionsisotermer skikt för skikt på avkryllad massa visade att PAE adsorberade i större mängd än CMC, både i hänseende av massa och laddning. Adsorptionen av PAE var signifikant långsammare än CMC och adsorptionstiden till 90% av mättnadsadsorptionen bestämdes till 3 respektive 1 minut. Zetapotentialen för kryll bestämdes för adsorption av de två första polyelektrolytskikten och resultaten tydde på att kryllmaterialet omladdade inom en minut efter tillsatserna av polyelektrolyt. Reflektometriförsök inom sekventiell adsorption av PAE och CMC på kiseloxid antydde att den låga molekylviktsfraktionen av PAE störde uppbyggnaden av polyelektrolyt-multiskikten. / This thesis presents experimental studies of polyelectrolyte adsorption on oppositely charged surfaces, where substrates of both silica and bleached softwood kraft pulp were used. A major aim of this research was to characterise the conformation of adsorbed layers of cationic polyacrylamide (CPAM), in comparison to cationic dextran (Cdextran), and relate this information to the binding capacity of colloidal silica. A second aim in this thesis was to study the kinetics of the sequential adsorption of polyamide epichlorohydrine (PAE) and carboxymethyl cellulose (CMC) on pulp fibres, and to determine the adsorption isotherms for the layer-by-layer deposition of polyelectrolytes on pulp fibres. The adsorption of CPAM on silica surfaces was studied using stagnation point adsorption reflectometry and quartz crystal microgravimetry to determine its adsorption kinetics as well as the dependencies of polyelectrolyte charge densities, pH, and NaCl concentration on saturation adsorption. The conformation of adsorbed layers of CPAM and Cdextran, analysed in terms of amount of water and layer thickness, was determined both before and after the secondary adsorption of colloidal silica (CS), and the adsorption of CS was also quantified as a function of the surface coverage of the polyelectrolyte. Results indicate that the charge density of CPAM controlled the amount of the polyelectrolyte adsorbed on silica surfaces at low NaCl concentrations. The adsorption of both CPAM and Cdextran on silica was shown to be effective at up to 1 M NaCl concentrations, which indicates that non-ionic interactions between the polyelectrolytes and silica contribute significantly. CS adsorption was higher on pre-adsorbed CPAM than on Cdextran. The conformation of the adsorbed layer after CS addition was seen to expand significantly in CPAM-based layers, while the Cdextran layer appeared to restore its conformation after a temporary expansion at low salt concentrations. In the second part of the thesis, the sequential adsorption of PAE and CMC on pulp fibres was determined using the polyelectrolyte titration technique. Layer-by-layer adsorption isotherms derived on fractionated pulp showed that PAE adsorbed in higher amounts than CMC did, both in terms of adsorbed mass and adsorbed charge. The adsorption of PAE was significantly slower compared to CMC, and the adsorption times required to reach 90% of the saturation adsorption were 3 and 1 min, respectively. The zeta potential of pulp fines was determined for the adsorption of the two first polyelectrolyte layers, and data indicated that the fines recharge within one minute after the polyelectrolyte additions. Reflectometry experiments regarding the sequential adsorption of PAE and CMC on silica indicated that the low-molecular-weight fraction of PAE disturbed the formation of polyelectrolyte multilayers. / QC 20101112

The nuclear lamina protein, lamin A is produced by proteolytic cleavage of a 74 kDa precursor protein, prelamin A. The conversion of this precursor to mature lamin A is mediated by a specific endoprotease, prelamin A endoprotease. Subnuclear fractionation indicates that the prelamin A endoprotease is localized at the nuclear membrane. The enzyme appears to be an integral membrane protein, as it can only be removed from the nuclear envelope with detergent. It is effectively solubilized by the detergent n-octyl-beta-D-glucopyranoside and can be partially-purified (approximately 1200-fold) by size exclusion and cation exchange (Mono S) chromatography. Prelamin A endoprotease from HeLa cells was eluted from Mono S with 0.3 M sodium chloride as a single peak of activity. SDS-PAGE analysis of this prelamin A endoprotease preparation shows that it contains one major polypeptide at 65 kDa and smaller amounts of a second 68 kDa polypeptide. Inhibition of the enzyme activity in this preparation by specific serine protease inhibitors is consistent with the enzyme being a serine protease.

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