Surfactant related recovery processes are of increasing interest and importance because of high oil prices and the urge to meet energy demand. High oil prices and the accompanying revival of EOR operations have provided academia and industry with great opportunities to test alkaline surfactant polymer (ASP) methods on a field scale and to develop novel surfactant systems that can improve the performance of such EOR processes. This dissertation intends to discuss both opportunities through two unique projects, the development of novel surfactants for EOR applications and the design for an alkaline/surfactant/polymer (ASP) field pilot. In Section I of this dissertation, a novel series of anionic Gemini surfactants are carefully synthesized and systematically investigated. The remarkable abilities of Gemini surfactants to influence oil-water interfaces and aqueous solution properties are fully demonstrated. These surfactants are shown to have great potential for application in EOR processes. A wide range of Gemini structures (C₁₄ to C₂₄ chain length, -C2- and -C4- spacers, sulfate and carboxylate head groups) was synthesized and shown to have high aqueous solubility, with Krafft points below 20°C. The critical micelle concentrations (CMC) for these new molecules are measured to be orders of magnitude lower than their conventional counterparts. The significantly more negative Gibbs free energy for Gemini surfactant drives the micellization process and results in ultralow CMC. An adsorption study of Gemini surfactants at air-water and solid-water interfaces shows their superior surface activity from tighter molecular packing, and attractive characteristics of low adsorption loss at the solid surface. All anionic Gemini surfactants synthesized have an extraordinary tolerance to salinity and/or hardness. No phase separation or precipitation occurs in the aqueous stability tests, even in the presence of extremely high concentrations of mono- and/or di-valent ions. Moreover, ultra-low IFT values are reached under these conditions for Type I microemulsion systems, at very low surfactant concentrations. The stronger molecular interaction between the Gemini and conventional surfactants offers synergy that promotes aqueous stability and interfacial activity. Gemini molecules with short spacers are capable of giving rise to high viscosities at fairly low concentrations. The rheological behavior can be explained by changes in the micellar structure. A molecular thermodynamic model is developed to study anionic Gemini surfactants aggregation behavior in solution. The model takes into account of the head group-counter-ion binding effect and utilizes two simplified solutions to the Poisson-Boltzmann equation. It properly predicts the CMC of the surfactants synthesized and can be easily expanded to investigate other factors of interest in the micellization process. Section II of this dissertation studies chemical formulation design and implementation for an oilfield where an alkaline/surfactant/polymer (ASP) pilot is being carried out. A four-step systematic design approach, composed of a) process and material selection; b) formulation optimization; c) coreflood validation; 4) lab-scale simulation, was successfully implemented and could be easily transferred to other EOR projects. The optimal chemical formulation recovered over 90% residual oil from Berea coreflood. Lab-scale simulation model accurately history matches the coreflood experiment and sets the foundation for pilot-scale numerical study. Different operating strategies are investigated using a pilot-scale model, as well as the sensitivities of project economics to various design parameters. A field execution plan is proposed based on the results of the simulation study. A surface facility conceptual design is put together based on the practical needs and conditions in the field. Key lessons learned throughout the project are summarized and are invaluable for planning and designing future pilot floods. / text

For over a decade, diquaternary ammonium gemini surfactants have shown promise as non-viral gene delivery agents in both in vitro and in vivo systems. Their continued development, however, requires an understanding of their biological fate. The absence of identification and quantification methods that can achieve that goal is what drove the development of simple and rapid mass spectrometry (MS)-based methods; the focus of my Ph.D. dissertation. Prior to the development of these MS-based methods, an understanding of the gas phase behavior of diquaternary ammonium gemini surfactants is required. The development of a universal fragmentation pathway for gemini surfactants was achieved using low resolution and high resolution MS instruments. Single stage (MS), tandem stage (MS/MS and quasi-multi-stage (quasi MS3) mass spectrometry analysis allowed for the confirmation of the molecular composition and structure of each gemini surfactant through the identification of common and unique mass to charge values. Understanding the fragmentation behavior allowed for the specific identification and/or quantification of gemini surfactants by MS-based methods; including liquid chromatography low resolution tandem mass spectrometry (LC-LR-MS/MS), fast chromatography low resolution tandem mass spectrometry, fast chromatography high resolution mass spectrometry, desorption electrospray ionization low resolution mass spectrometry and matrix assisted laser desorption ionization high resolution mass spectrometry. We hypothesized that a LC-LR-MS/MS method would be the most effective quantitative method for the quantification of N,N-bis(dimethylhexadecyl)-1,3-propane-diammonium dibromide (G16-3) within PAM212 cellular lysate; achieving the lowest lower limit of quantification (LLOQ). Although the LC-LR-MS/MS method achieved a LLOQ suitable for analysis of G16-3 within PAM212 cell lysate, its limitations made it an inefficient method. In comparison, the four alternative mass spectrometry methods were faster, more efficient and less expensive than a conventional LC-LR-MS/MS method for the post transfection quantification of G16-3 within PAM212 cell lysate to be determined; 1.45 ± 0.06 μM. Future application of the universal fragmentation pathway and each MS-based quantification method will be beneficial for the future development of diquaternary ammonium gemini surfactants to further understand their post transfection fate.

To achieve successful gene therapy, safe and efficient gene delivery vectors are needed. As an alternative to viral vectors, non-viral vectors, incorporating compounds such as cationic polymers and lipids have been widely studied. Much effort has been made to enhance transgene delivery efficiency, such as development of more effective cationic lipids or polymers, optimization of transfection formulations, and investigation on structural-activity of delivery vectors. Gemini surfactant, consisting of two surfactant monomers linked by a spacer group, is a thrust research area for gene therapy as non-viral vectors due to their high stability, longer storage on shelves, easiness to produce. A series of phytanyl substituted asymmetric gemini surfactants, phy-3-m (m = 12, 16, and 18) and phy-7NH-m (m = 12, 16, and 18), were rationally designed and synthesized. Due to the bulky nature and increased hydrophobicity of phytanyl branch, phy-3-m surfactants showed much lower values of critical micelle concentration (CMC) compared to their corresponding symmetric m-3-m. Particle size and transmission electron microscopy (TEM) imaging indicate that this type of gemini surfactants tends to form stacked bilayers rather than spherical or rod-like micelles which are typically observed in gemini surfactants with shorter spacers. Phy-3-m surfactants have higher degree of micelle ionization, indicating that the counter ions of the gemini surfactants can be easily replaced by other anionic ions, such as DNA, which is an advantage of phy-3-m used as transgene vectors. To evaluate transfection ability, transfection assays were carried out in OVCAR-3 cells. Transfection complexes formed by a plasmid pVGtelRL, coding enhanced green fluorescence protein (EGFP) gene, phy-3-m, and a neutral lipid, 1,2-Dioleyl-sn-glycerophosphatidylethanolamine (DOPE), at the charge ratios (+/-) of 2:1, 5:1, 10:1, and 20:1, were incubated with OVCAR-3 cells. Treated cells at all charge ratios except 20:1 showed EGFP signals under fluorescence microscopy. Meanwhile, EGFP expression and cell toxicity was quantified using fluorescence-activated cell sorting (FACS). For each gemini surfactant complex, the transfection efficiency and cytotoxicity go through a maximum, occurring at different values of the charge ratio. Considering both transfection efficiency and cytotoxicity, the optimal charge ratio to formulate the complexes containing phy-3-m was found to be 5:1 for in vitro transfection. Compared to a positive control, 16-3-16, phy-3-m showed higher transfection ability and lower cytotoxicity to OVCAR-3 cells. Initial characterization of transfection complexes was investigated by measuring particle size and zeta potential. At all charge ratios, transfection complexes were positively charged, and greater than +30 mV at 5:1 and 10:1, indicating that the complexes would be stable in solution at the ratio above 2:1. Transfection complexes were larger at lower charge ratio, but particle size dropped with increasing charge ratio (+/-). Comparing particle size and zeta potential with transfection efficiency, no correlation between size/zeta potential and transfection ability was observed. The larger particles may enter cells through caveolin-mediated pathway or phagocytosis, and smaller ones through a clathrin-mediated endocytosis. In addition, phase structures of the complexes were investigated using small angle X-ray scattering (SAXS). The complexes containing phy-3-m gemini surfactants were found to be able to adopt multiple phase structures, such as L, HII, and other highly ordered unidentified phase structures. By contrast, L structure was dominant in the transfection complexes formed by 16-3-16. The ability of phy-3-m system to adopt multiple phases appears correlated with their higher transfection efficiency in OVCAR-3 cells.

No description available.

This dissertation presents two chemo-dynamical analyses of metal-poor stars found within the Milky Way. 115 metal-poor candidate stars, including 28 confirmed very metal-poor stars, selected from the narrow-band Pristine photometric survey are presented based on CFHT high-resolution ESPaDOnS spectroscopy. An additional 30 confirmed very metal-poor stars selected from Pristine are examined based on Gemini/GRACES spectroscopy. Chemical abundances are determined for a total of 19 elements (Li, Na, Mg, K, Ca, Sc, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Y, Zr, Ba, La, Nd, Eu) across these studies, which are combined with Gaia DR2 parallaxes and proper motions to paint a chemically diverse map of ancient stars in the Galaxy. Abundance patterns similar to those seen in "normal" metal-poor Galactic halo stars are found in a majority of the stars studied here, however new discoveries of a handful of chemically unique and kinematically intriguing metal-poor stars are presented. The chemo-dynamics of these novel stellar relics point towards chemical signatures of unique and potentially unstudied stellar yields, in addition to stars with origins in accreted dwarf galaxies and the ancient progenitors of the proto-Milky Way. The success of these relatively small studies heralds the great contributions to Galactic archaeology expected from the next generation of large multi-object spectroscopic surveys. Contained within are two other projects that introduce data products related to Gemini Observatory instruments. A version of the convolutional neural network StarNet, tuned to medium-resolution R~6000 H-band spectra is presented. This model was trained on synthetic stellar spectra containing a range of data augmentation steps to more accurately reflect the observed spectra expected from medium-resolution instruments, like the Gemini-North Near-Infrared Integral Field Spectrometer (NIFS) or GIRMOS. In an era when spectroscopic surveys are capable of collecting spectra for hundreds of thousands of stars, fast and efficient analysis methods are required to maximize scientific impact, and StarNet delivers on these expectations over a range of spectral resolutions. Finally, a python package called Nifty4Gemini, and its associated Pyraf/Python based pipeline for processing NIFS observations is included. Nifty4Gemini reduces NIFS raw data and produces a flux and wavelength calibrated science cube with the full signal-to-noise, ready for science analysis. / Graduate

HD 106906 is a young, binary stellar system, located at ~103.3 parsecs away in the Lower Centaurus Crux (LCC) group. This system is completely unique among known systems in that it contains an asymmetrical debris disk, as well as an 11 M(Jup) planet companion, at a separation of ~735 AU. Only 4 other systems are known to contain both a disk and detected planet, where HD 106906 is the only one in which the planet has apparently been ejected. Furthermore, the debris disk is nearly edge on, and extends roughly from 70 AU to >500 AU, where previous polarimetric studies with HST have shown the outer regions to have high asymmetry. The presence of a planet companion sparks questions about the origin of this asymmetry. To better understand the structure and composition of the disk, deeper data have been taken with the Gemini Planet Imager (GPI), which we have used to perform a deep polarimetric study of HD 106906’s asymmetrical debris disk. The data were taken in the H-band, and were supplemented with both J- and K1-band polarimetric data which have been obtained through one of GPI’s Large and Long Programs (LLP). Polarimetry is important in the study of debris disks in scattered light, as it helps us constrain their dust grain characteristics, as well as allowing us to obtain high-contrast images. Modelling the disk, along with an empirical analysis of our data, supports a disk that is asymmetrical in surface brightness and structure, as well as a disk that is highly eccentric. These results will be discussed in terms of possible sources of asymmetry, such as dynamical interaction with the planet companion HD 106906b. / Graduate / 2021-07-26

Cancer is currently the second most common cause of death in the world. Despite tremendous progress in the treatment of different forms of cancer, the five year survival rates for lung, colorectal, breast, prostate, pancreatic and ovarian cancers remain quite low. New therapies are urgently needed for the better management of these diseases. In this context, both therapeutic gene and drug delivery constitute promising approaches for cancer treatment and are addressed in this thesis. Focusing on gene delivery, we are proposing the use new pyridinium amphiphiles for obtaining gene delivery systems with improved stability and efficiency and low toxicity (Chapters 2 and 3). The main focus was on pyridinium gemini surfactants (GSs), which possess a soft charge, a high charge/mass ratio and a high molecular flexibility - all key parameters that recommend their use in synthetic gene delivery systems with in vitro and in vivo efficiency. In Chapter 2, we optimized a novel DNA delivery systems through interfacial engineering of pyridinium GS at the level of linker, hydrophobic chains and counterions. In Chapter 3, we tested the effects of blending pyridinium cationic GS into pyridinium cationic lipid bilayers and we have evaluated these blends towards plasmid DNA compaction and delivery process. We have also correlated the cationic bilayer composition with the dynamics of the DNA compaction process, and with transfection efficiency, cytotoxicity and internalization mechanism of resulted nucleic acid complexes. Toward improved drug delivery systems, we introduced new amphiphilic block copolymers synthesized from biocompatible and biodegradable segments. Although their capabilites for loading, transport and release of lipophilic substances stored in their hydrophobic cores are widely known, their stability in vivo is limited due to rapid degradation by esterases present in the body. In Chapter 4, we examined the possibility to increase the enzymatic stability of PEG-PCL macromolecular amphiphiles through interfacial engineering, in a process which separates the hydrophilic/hydrophobic interface from the degradable/non-degradable block interface. We evaluated the stability, toxicity, drug loading and release properties of these new polymers using docetaxel as a model chemotherapeutic drug. The results revealed how hydrophilic/ hydrophobic interface tuning can be used to adjust key properties of polymeric drug delivery systems of this type. / Pharmaceutical Sciences

The biggest hurdle in success of gene and drug therapy is designing and preparation of suitable bio-nanomaterials to carry the desired nucleic acid and drug to the targeted site. The work described in the present thesis encompasses two different approaches for the delivery of bioactive oligo/polynucleotides and drugs in vitro and in vivo using either cationic lipids or their nanocomposites with different carbon nanomaterials. The idea of using carriers for oligo/polynucleotides and drugs came into existence because of numerous physiological barriers in pathway of delivery of naked oligo/polynucleotides or drugs which reduces the overall activity of these bioactives in biological systems. These barriers trigger scientific research toward the preparation of appropriate biomaterials which can overcome the physiological barriers and improve the activity of bioactive oligo/polynucleotides and drugs in cellular systems. Toward this end, the design and synthesis of different cationic lipids and carbon nanomaterials were undertaken as described in seven chapters of the thesis. A series of novel cationic lipids with structural variability was prepared and used for gene delivery in vitro. They were further tuned chemically to sustain delivery efficiency in high serum percentage during in vitro transfection. These serum compatible lipids were used to perform transfection of reporter gene plasmid and found to be more efficient compared to the some well known commercial products for the same purpose. Another series of novel lipids were synthesized for the targeted gene delivery in vitro. These tryptophan based cholesteryl lipids were used to prepare mixed liposomes. These mixed liposomes were highly efficient in targeting sigma receptor rich HEK293T over sigma receptor negative HeLa cells. Mixed liposomes were also prepared for selective targeting of αvβ3 and αvβ5 integrins in gene transfection protocol using a palmitoyl-RAFT-RGD4 template. A mixed liposomal formulation was developed to carry out anti-sense siRNA mediated knockdown of Smad-2 protein with better efficiency compared to some of the best known commercial products for the same purpose. These mixed liposomes were also highly efficient for regression via induction of p53 mediated apoptosis in xenograft tumors developed in nude mice. Carbon nanomaterials have been extensively explored as nanoscale gene/drug carriers for potential applications. But the challenge is to solubilize these highly hydrophobic materials in aqueous medium for use in biological systems. Although there are reports for covalent modifications of such nanomaterials but it could be done only with the loss of some beneficial features of these materials. Herein a non-covalent technique has been efficiently used to suspend single walled carbon nanotubes in water using biocompatible cationic lipids. These nanosuspensions were used to complex plasmid DNA and transfect them in vitro. They proved to be highly serum compatible DNA carriers which did not drop the efficiency even in very high percentage of serum. Similarly exfoliated graphene was modified with cationic lipid and serum components to improve IC50 of Tamoxifen citrate and Methotrexate to a considerable extent in vitro. The improved Methotrexate formulations were highly efficient for regression in size of xenograft tumors developed in nude mice. Thus, the present thesis entails generation of cationic lipids and carbon nanomaterials based nanocomposites which were not only highly biocompatible themselves but their efficiency was found many fold better compare to some of the best commercial delivery agents. These were useful for the delivery of various bioactive oligo/polynucleotides and drugs in vitro and in vivo.

La présente étude est une approche holistique axée sur l'étude des effets spécifiques d'ions sur les propriétés d'auto-assemblage de tensioactifs cationiques gemini. Notre objectif principal étant l’étude de l'effet de divers contre-ions sur les caractéristiques d’auto-assemblage de tensioactifs cationiques en solution aqueuse. Afin d'obtenir une vision plus complète de l'effet des interactions ioniques et moléculaires à l’interface sur les propriétés globales, nous avons utilisé des approches différentes. Nous avons combiné une étude expérimentale portant sur les propriétés en solution (concentration micellaire critique, degré d'ionisation, nombre d'agrégation, etc.), avec des approches centrées sur l'étude des propriétés micellaires interfaciales en analysant les concentrations des contre-ions et de l'eau de façon expérimentale (piégeage chimique) et informatique (simulations de dynamique moléculaire). En outre, nous avons étudié l'impact de la nature des contre-ions sur la croissance des micelles géantes par rhéologie. En plus de l'examen des propriétés de tensio-actifs en solution, les effets spécifiques d'ions sur les structures cristallines des agents tensioactifs gémini ont été étudiés.Nous avons trouvé que les effets d'ions spécifiques qui déterminent le comportement des agrégats micellaires de gemini cationiques d'ammonium quaternaire dans des solutions aqueuses dépendent fortement de l'énergie libre d'hydratation des contre-ions, en d'autres termes, sur leur propriétés hydrophile /hydrophobe. Contrairement à la solution aqueuse, dans les cristaux, la taille de l'ion devient le facteur déterminant. La comparaison des résultats obtenus pour un même système en solution aqueuse et à l'état solide a montré l'importance des interactions ion-eau dans les effets spécifiques d'ions. Cependant, il faut noter que les propriétés du substrat (les gemini dans notre cas) doivent être prises en compte non moins soigneusement afin de prédire complétement les effets Hofmeister. / The present study is a holistic approach focused on the investigation of ion specific effects on the self-assembly properties of cationic gemini surfactants. Our main focus was on the effect of various counterions on the self-organization features of cationic surfactants in aqueous solution. In order to obtain amore comprehensive understanding of the effect of interfacial ionic and molecular interactions on aggregate properties we used different approaches. We combined an experimental study focused on the bulk solution properties (critical micelle concentration, ionization degree, aggregation number, etc.), with approaches focused on investigating the interfacial micellar properties by analyzing the interfacial counterion and waterconcentrations, experimentally (chemical trapping) and computationally (molecular dynamic simulations). Moreover, the impact of counterion nature was investigated by studying the growth of wormlike micelles using rheology. Besides the examination of the surfactants properties in solution, the ion specific effects onthe crystalline structures of gemini surfactants were studied.We found that ion specific effects which determine the behavior of micellar aggregates of cationic quaternary ammonium gemini in aqueous solutions strongly depend on the free energy of hydration of the counterions, in others words, on their hydrophilic/hydrophobic properties. Contrarily to aqueous solution, in crystals, the size of the ion becomes the determining factor. Comparison of the results obtained for the same system in aqueous solution and in solid state showed the importance of ion-water interactions in ion specific effects. However, one should note that the properties of substrate (the gemini in our case) should be taken into account not less carefully in order to fully predict Hofmeister effects.

In 1964, Benjamin Britten met the multi-instrumentalist twins Zoltán and Gábor Jeney while traveling in Budapest. At their behest, Britten composed Gemini Variations: Twelve Variations and Fugue on an Epigram by Kodály, a work which exploited the brothers' abilities on multiple instruments: Zoltán on flute and piano, and Gábor on violin and piano. In foreseeing the difficulties of programming this work, Britten simultaneously arranged a version for four players: flute, violin, and four-hand piano, eliminating the need for switching instruments. Despite this arrangement, as well as a very public and highly anticipated premiere at the Aldeburgh Festival in 1965, Gemini Variations has remained neglected by performers and scholars alike. This document serves to 1) promote a work that can justifiably be considered as part of the chamber music repertoire involving flute; 2) advocate for its musical merit and appropriateness for chamber music concerts made up of more traditional groups of players; 3) compare the two-player and four-player versions Britten wrote; and 4) explore the likely reasons why a piece by one of the most celebrated composers of the twentieth century has remained largely ignored for over fifty years.