Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4738. Adviser: Umberto Ravaioli. Includes bibliographical references (leaves 69-72) Available on microfilm from Pro Quest Information and Learning.

<p> Visualization of gene expression has led to a revolution in biology over the past two decades. Primarily this visualization has occurred using fluorescent proteins, like GFP, that can be directly visualized with microscopy. Fluorescence imaging is limited by depth of penetration when applied to living mice or humans however. For this, MRI, ultrasound and other modalities are under continual development for <i>in vivo</i> applications. Ideally, every <i> in vivo</i> imaging modality would have their own reporter genes, allowing for unconstrained genetic studies of structure and function. The current wealth of bioinformatics data presents a rich pallet of starting materials for bioengineering this next generation of reporter proteins. </p><p> This work utilized multiple approaches to creating reporters: cell labeling with, "Biotag" derived from a bacterial biotinylation enzyme and substrate; genetically controlled absorption of the MRI contrast agent Mn via the metal transport protein DMT1; and sequestration of Mn using the metal sensing transcription factor MntR. The reporter proteins were implemented in tissue culture and living mice to give a new view of gene expression in processes such as neural and vascular development. Moreover, the development process yielded new insights into the proteins themselves and the context in which they function. Each method has particular strengths and limitations but are, at present, the vanguard of <i>in vivo</i> molecular imaging. </p>

Thesis (Ph.D.)--Lehigh University, 2008.

Thesis (Ph. D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3588. Adviser: Huimin Zhao. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1142. Adviser: Chang Liu. Includes bibliographical references (leaves 101-110) Available on microfilm from Pro Quest Information and Learning.

Molecular electrostatic potentials (MEPs) and vibrational electronics (“vibronics”) have developed into novel scenarios proposed by our group to process information at the molecular level. They along with the traditional current-voltage scenario can be used to design and develop molecular devices for the next generation electronics. Control and communication features of these scenarios strongly help in the production of “smart” devices able to take decisions and act autonomously in aggressive environments. In sensor science, the ultimate detector of an agent molecule is another molecule that can respond quickly and selectively among several agents. The purpose of this project is the design and development of molecular sensors based on the MEPs and vibronics scenarios to feature two different and distinguishable states of conductance, including a nano-micro interface to address and interconnect the output from the molecular world to standard micro-technologies. In this dissertation, theoretical calculations of the electrical properties such as the electron transport on molecular junctions are performed for the components of the sensor system. Proofs of concept experiments complement our analysis, which includes an electrical characterization of the devices and measurement of conductance states that may be useful for the sensing mechanism. In order to focus this work within the very broad array between nanoelectronic and molecular electronics, we define the new field of Molecular Engineering, which will have the mission to design molecular and atomistic devices and set them into useful systems. Our molecular engineering approach begins with a search for an optimum fit material to achieve the proposed goals; our published results suggest graphene as the best material to read signals from molecules, amplify the communication between molecular scenarios, and develop sensors of molecular agents with high sensitivity and selectivity. Specifically, this is possible in the case of sensors, thanks to the graphene atomic cross section (morphology), plasmonic surface (delocalized charge) and exceptional mechanical and electrical properties. Deliverables from this work are molecular devices and amplifiers able to read information encoded and processed at the molecular level and to amplify those signals to levels compatible with standard microelectronics. This design of molecular devices is a primordial step in the development of devices at the nanometer scale, which promises the next generation of sensors of chemical and biological agents molecularly sensitive, selective and intelligent.

Cette thèse s’inscrit dans la conjoncture actuelle de la recherche et du développement des matériaux pour les énergies renouvelables et dispositifs optoélectroniques à bas coût. Nous avons développées des nouveaux matériaux de pérovskites 2D et 3D afin d’exploiter leurs propriétés originales dans le but de les intégrer dans un second temps dans des dispositifs photoniques et photovoltaïques. Le travail d’ingénierie moléculaire sur la flexibilité des pérovskites 2D a permis de moduler le gap optique, d’extraire des informations sur les propriétés excitonique ainsi que l’activation de la photoluminescence. Quant à la flexibilité de la mise en forme des nouvelles pistes ont été initiées. L’étude de cette pérovskite 3D spécialement MAPI est très utile pour les applications photovoltaïques. La connaissance des propriétés optiques, structurales et de transport est une clé majeure pour l’augmentation des rendements et la stabilité de ces cellules / This thesis is involved in the current situation of research and development of materials for renewable energy and optoelectronic devices at low cost.We have developed new 2D and 3D perovskite materials to exploit their unique properties in order to integrate them in a second time in photonic and photovoltaic devices. The molecular engineering work on flexibility perovskites 2D allowed to modulate the optical gap, to extract information about the properties excitonqiue as well as activation of the photoluminescence. As to the flexibility of the layout of the new tracks were initiated.The study of this 3D perovskite especially MAPI is very useful for photovoltaic applications. The knowledge of the optical properties, structural and transport is a major key to increased yields and stability of these cells.

Les procédés de bioraffinerie, et notamment les agrocarburants, sont aujourd'hui reconnus comme essentiels pour sortir de l'économie actuelle basée sur le pétrole. Dans le cas du bioéthanol produit à partir de biomasse lignocellulosique, l'hydrolyse enzymatique par les enzymes de Trichoderma reesei est le principal point faible du procédé et doit être améliorée. Ces travaux de thèse s'intègrent dans le cadre du projet Futurol, et ont pour objectif d'identifier de nouvelles enzymes capables d'améliorer l'activité de T. reesei sur la lignocellulose. Une analyse post-génomique réalisée sur les secrétomes de vingt souches fongiques s'est révélée particulièrement prometteuse pour l'identification d'enzymes lignocellulolytiques d'intérêt. Une approche de génomique comparative a également abouti à la sélection de deux endo-mannanases de famille GH5 et GH26 chez le champignon Podospora anserina. Ces hémicellulases ont permis d'améliorer significativement la libération de glucose par T. reesei à partir d'épicéa. Une étude fondamentale approfondie a permis de résoudre les structures cristallographiques et de mettre en évidence les relations entre les spécificités enzymatiques de chaque enzyme et leurs caractéristiques structurales. La structure tridimensionnelle de la mannanase GH26 couplée à son CBM35 présente un linker court et rigide et une organisation du site actif atypique. Les deux mannanases ont également fait l'objet d'un travail d'ingénierie aléatoire qui a abouti à des variants des deux enzymes présentant une amélioration de l'efficacité catalytique et/ou une modification de spécificité. / Biorefineries such as biofuels are nowadays considered as essential to reduce our dependence on oil products. In the production process of bioethanol from lignocellulosic biomass, enzymatic hydrolysis performed by Trichoderma reesei enzymes is the main bottleneck of the process and requires improvements.The present work is part of the Futurol project, and aims at identifying new enzymes to improve the activity of T. reesei toward lignocellulose. Post-genomic analyses on twenty fungal strains have revealed the potential of this approach to identify lignocellulolytic enzymes of interest. Comparative genomics also led to the selection of two endo-mannanases from families GH5 and GH26 from the fungus Podospora anserina. These hemicellulases significantly improved glucose release upon T. reesei hydrolysis of spruce. An in-depth fondamental study allowed the solving of cristallographic structures and revealed the relationships between enzymatic specificities and structural characteristics. The structure of GH26 catalytic module appended to CBM35 highlighted a short and rigid linker and an atypical active site organization. The two mannanases were subjected to molecular engineering. Variants displaying improved catalytic efficiency and/or modified specificity were identified for both enzymes.

Dye-sensitized solar cells (DSSCs) present an interesting method for the conversion of sunlight into electricity. Unlike in other photovoltaic technologies, the difficult tasks of light absorption and charge transport are handled by two different materials in DSSCs. At the heart of the DSSC, molecular light absorbers (dyes) are responsible for converting light into current. In this thesis the design, synthesis and properties of new metal-free D-π-A dyes for dye-sensitized solar cells will be explored. The thesis is divided into six parts: Part one offers a general introduction to DSSCs, dye design and device characterization. Part two is an investigation of a series of donor substituted dyes where structural benefits are compared against electronic benefits. In part three a dye assembly consisting of a chromophore tethered to two electronically decoupled donors is described. The assembly, capable of intramolecular regeneration, is found to impede recombination. Part four explores a method for rapidly synthesizing new D-π-A dyes by dividing them into donor, linker and acceptor fragments that can be assembled in two simple steps. The method is applied to synthesize a series of linker varied dyes for cobalt based redox mediators that builds upon the experience from part two. Part five describes the synthesis of a bromoacrylic acid based dye and explores the photoisomerization of a few bromo- and cyanoacrylic acid based dyes. Finally, in part six the experiences from previous chapters are combined in the design and synthesis of a D-π-A dye bearing a new pyridinedicarboxylic acid acceptor and anchoring group. / <p>QC 20140509</p>

<p>Lithium-ion batteries are regarded as the batteries that could potentially change the world. From consumer electronics and electric vehicles to energy storage systems and aerospace applications, Li-ion based batteries have become the norm. Although these batteries show a lot of promise to rid the world of several challenges in the future, there are still a few shortcomings of this battery that need to be addressed. It is also important to note the recent accidents caused due to the explosion of these lithium-ion batteries, to name a few: Samsung Galaxy Note 7 explosion, e-cigarettes battery explosion, overheating of lithium batteries present in Apple MacBook Pro laptop. This calls for a more reliable and accurate Battery Management System (BMS). One of the major shortcomings in today’s available battery management systems is the accuracy of the measurement of charge present in lithium-ion batteries, termed as State-of-Charge (SoC) and State-of-Energy (SoE) of the battery. </p> <p>To address this problem, a highly sensitive and a high-resolution system is developed to estimate the State-of-Charge based on the changes in impedance of a sensor coil which is caused due to the effect of Eddy Current Power Loss in the battery. The redox reaction taking place inside a battery suggest that lithium ions are exchanged back-and-forth between anode and cathode during an event of charging and/or discharging of the battery. This gives rise to change in electrical resistivity of the battery electrode materials. A sensor coil which is excited with an AC magnetic field induces Eddy currents on the internal components of the battery. Based on the change in resistivity of the electrode materials, eddy current and hence the power loss due to Eddy currents change. This in turn changes the complex impedance of the sensor coil, which is mapped to estimate the SoC of the battery. The results confirm the superiority of the proposed technique in terms of sensitivity, resolution, computational complexity and cost of the measured SoC in comparison with other existing methods of estimating SoC. This can be a potential method to estimate SoE of the battery as well. </p>