本篇分享17位斯隆研究獎化學領域獲得者的博士論文。這些論文收錄在ProQuest全球博碩士論文全文資料庫（ProQuest Dissertations & Theses Global，簡稱PQDT Global） 資料庫中，讀者可通過該庫查閱、利用這些高品質的博士論文。
The Electrocatalytic Evolution of Oxygen and Hydrogen by Cobalt and Nickel Compounds
作者：Bediako, Daniel Kwabena Dakwa
導師：Nocera, Daniel G.; Betley, Theodore; Dinca, Mircea
學位授予機構：Harvard University
論文連結：
https://www.proquest.com/pqdtglobal/docview/1746625531/
摘要：
In order to meet the ever-increasing demand for energy, a worldwide transition away from fossil fuels to renewable solar–fuels is required. However, the intermittency of local insolation mandates a cost-effective and efficient storage scheme. Using solar-derived electricity to drive the thermodynamically uphill water splitting reaction to generate dihydrogen and dioxygen is one promising method of storing solar energy in fuels. This “artificial photosynthesis” scheme requires the execution of two half-reactions, one involving the oxidation of water to O2—the oxygen evolution reaction (OER)—and the other entailing the reduction of hydrogen ions to H2—the hydrogen evolution reaction (HER). Accomplishing these electrocatalytic reactions stresses the development of catalysts that are capable of mediating reactions that are in net multi-electron, multi-proton transformations.
Nano and Molecular Scale Dielectrics: Encapsulated Inorganic Nanoparticle-Polymer Nanocomposites and Self-Assembled Nanodielectrics, Theory and Experiments
作者：Fredin, Lisa
導師：Marks, Tobin J.; Ratner, Mark A.
學位授予機構：Northwestern University
論文連結：
https://www.proquest.com/pqdtglobal/docview/1269177172/
摘要：
This thesis focuses on combining knowledge gained from experiments and theoretical modeling to create better dielectric materials. Using fundamental insights gained by performing experiments and therefore understanding the spectrum of dielectric responses measured, we have been able to pinpoint areas where the models being used are not accurately describing the response of the material. By understanding the assumptions made by and the physics behind the models being used, we have been able to design experiments that measure the phenomena the models are trying to replicate. These insights have lead to the initial development better models that accurately capture the nature of the materials and their responses and to the creation of high performing dielectric materials.
On the Origins of Catalysis by Ketosteroid Isomerase
作者：Fried, Stephen D.
導師：Boxer, Steven G.; Fayer, Michael D.; Solomon, Edward I.
學位授予機構：Stanford University
論文連結：
https://www.proquest.com/pqdtglobal/docview/2499012722/
摘要：
Enzymes are complicated molecular machines that actuate nearly all biochemical processes with speed and specificity – their failure to do so nearly always has pathological consequences. Nevertheless, the origins of enzymes’ prodigious catalytic power remain elusive and hotly debated despite the abundance of structural data and intense research efforts spanning the previous 60 years. This doctoral dissertation pertains largely to studies on the small enzyme, ketosteroid isomerase (KSI). KSI is among the most well studied enzymes, and has been used by many as a model for interrogating the catalytic strategies in Nature’s toolbox. Its privileged status is warranted on account of it being one of the fastest enzymes known, accelerating its reaction’s rate by approximately one trillion times, and doing so using a commonly encountered mechanism in biochemistry. In the ensuing chapters, we shall delve into the active site of KSI with a broad range of tools ranging from traditional biochemistry and spectroscopy, to analytical theory and computer simulation.
Surface Chemistry to Control Bulk Reaction Dynamics of Native Point Defects in Rutile Titanium Dioxide
作者：Gilliard, Kandis Leslie
導師：Seebauer, Edmund
學位授予機構：University of Illinois at Urbana-Champaign
論文連結：
https://www.proquest.com/pqdtglobal/docview/2164937292/
摘要：
The properties of semiconductor materials depends on the type, concentration and spatial distribution of the point and extended defects it contains. For ceramic oxide semiconductor materials, the concentration and diffusion of cations and anions, in the form of interstitials and vacancies, plays a large role in the performance of these materials for gas sensing, photocatalysis, microelectronics and hotovoltaic cells. The ability to control the properties of semiconductors through defect manipulation, or “defect engineering”, has been studied and applied extensively in non-ceramic semiconductors such as Silicon. However, the use of defect engineering techniques to control the properties of ceramic oxide semiconductors is still in its nascency.
Investigations of Metabolic Pathways in Mycobacterium tuberculosis
作者：Hatzios, Stavroula K.
導師：Bertozzi, Carolyn R.
學位授予機構：University of California, Berkeley
論文連結：
https://www.proquest.com/pqdtglobal/docview/1319511999/
摘要：
This thesis explores three discrete metabolic pathways in Mtb that are likely to mediate its interactions with host immune cells. The first three chapters examine the sulfate assimilation pathway of Mtb and its regulation by the phosphatase CysQ. Chapter 1 provides a general overview of the transcriptional, biochemical, and molecular levels of sulfur metabolism regulation in Mtb, while Chapters 2 and 3 present a detailed analysis of how CysQ may influence sulfur transactions in the cell. Chapter 4 explores the biosynthesis of the cell wall glycolipid Polyacyltrehalose, which is exclusively synthesized by pathogenic mycobacteria and may mediate host-pathogen interactions. Finally, Chapter 5 describes a novel osmoregulatory pathway in Mtb that affects the pathogen’s response to osmotic stress and its production of the well-characterized virulence factor EspA.
A Combinatorial Peptoid-Based Platform for the Development of Selective Metal Binding Materials
作者：Knight, Abigail Sheldon
導師：Francis, Matthew B.
學位授予機構：University of California, Berkeley
論文連結：
https://www.proquest.com/pqdtglobal/docview/1917682650/
摘要：
Ligands with the ability to selectively chelate individual metals can be applied in heavy metal remediation, recycling, and metal separations, yet such ligands are currently rare and those processes are avoided or expensive due to the use of nonspecific methods. In order to identify compounds that will selectively chelate metal ions, we designed and synthesized a peptoid library and several screening methods to identify motifs capable of chelating low concentrations of various metal ions in complex sample media. Peptoids, or N-substituted glycine oligomers, are a recently developed class of peptidomimetics that have a variety of new structures and applications. The first target application was the remediation of water contaminated with toxic Cr(VI). Identified structures outperformed commercially available resins and demonstrated the ability to reduce the amount of Cr(VI) to levels within the range of the EPA guidelines. A new library generation was developed for the selective coordination of individual ions in a biological context. One target of this library was lethal Cd(II), and peptoid-based ligands were capable of reducing the concentrations of Cd(II) in human serum to 0.5 μM, comparable to the reported threshold for acute toxicity. After demonstrating the success of this screening platform, the platform has been adapted for many applications with a variety of metal ions described within. Towards the development of inexpensive functional materials, a biorthogonal bioconjugation reaction has been applied to immobilize peptoid sequences after synthesis. This work begins to illuminate the diverse array of applications of selective ligands for individual metal ions and demonstrates the potential for peptoids in highly functional materials.
Nanomaterials and Devices for Water and Air
作者：Liu, Chong（劉翀）
導師：Cui, Yi; Boehm, Alexandria; Cui, Bianxiao
學位授予機構：Stanford University
論文連結：
https://www.proquest.com/pqdtglobal/docview/2501265136/
摘要：
One of the challenges in sustainable development is to conserve the natural resources and environment. Fresh water and clean air are the foundation to the public health. However, the long existing and new emerging pollution problems have raised serious concerns. In my Ph.D. study, I worked on developing nanomaterials and nanotechnologies to provide new solutions to the environmental problems from rational design to device realization.
Density Functional Studies of Spatial and On-site Strong Correlations
作者：Liu, Zhenfei（劉振飛）
導師：Burke, Kieron
學位授予機構：University of California, Irvine
論文連結：
https://www.proquest.com/pqdtglobal/docview/1101049744/
摘要：
This dissertation consists of two parts. In the first part, I consider density functional calculations employing a reference system of strictly-correlated electrons, and develop the corresponding adiabatic connection formula and define a “decorrelation energy”. I then relate this scheme to the conventional Kohn-Sham scheme and the decorrelation energy to the conventional exchange-correlation energy. It provides an alternative perspective for understanding density functional theory and constructing approximate functionals. This scheme is particularly useful for systems with static correlation, such as stretched H2. In the second part, I consider electron transport through an Anderson junction. I show that Kohn-Sham conductance is exact at zero temperature and in the linear response regime, using the Friedel-Langreth sum rule. The Kohn-Sham potential is derived by inverting Bethe ansatz solution. I conclude that derivative discontinuity is a key feature for approximate functionals to yield accurate results at the strong correlation limit, namely the charge quantization and Kondo effect. I also analyze the successes and limitations of various approximations: smooth functionals, discontinuous functionals of the occupation, and symmetry-broken approach.
Metal-Organic Frameworks for Gas Storage and Separation
作者：Mason, Jarad Adam.
學位授予機構：University of California, Berkeley
論文連結：
https://www.proquest.com/pqdtglobal/docview/2046155791/
摘要：
The work presented in this dissertation describes the design, synthesis, and characterization of metal-organic frameworks for applications in gas storage and gas separations, with a specific focus on natural gas and hydrogen storage for mobile applications and on post-combustion carbon dioxide capture from coal- or natural gas-fired power plants. A wide variety of techniques and spectroscopic methods are covered, including gas adsorption, x-ray diffraction, infrared and UV-vis-NIR spectroscopies, and calorimetry.
Single molecule optical absorption spectroscopy at room temperature detected by scanning tunneling microscopy
作者：Nienhaus, Lea
學位授予機構：University of Illinois at Urbana-Champaign
論文連結：
https://www.proquest.com/pqdtglobal/docview/1744825228/
摘要：
The high spatial resolution of the scanning tunneling microscope makes it a powerful tool to investigate single molecules deposited on a variety of conductive or semi-conductive surfaces. By adding laser absorption, we are able to simultaneously examine single molecules with high spatial and high energy resolution. Our method of single molecule absorption detected by scanning tunneling microscopy (SMA-STM) relies on backside illumination to cut down on tip heating effects. The evanescent wave of a laser undergoing total internal reflection nearly saturates excitation of molecules on the surface, thus changing the net local density of states enough for STM detection. The excitation laser is amplitude modulated, allowing for simultaneous detection of the STM current (image) and its derivative (absorption signal) by a lock-in amplifier. Although this approach for the most part overcomes the junction heating effects, a new problem arises. It is no longer possible to use arbitrary substrates – apart from being atomically flat and conductive they must also be optically transparent at the wavelength of excitation.
Chain Conformation and Disorder in High Mobility Semiconducting Polymers: Understanding Charge Transport in Complex Microstructures
作者：Noriega-Manez, Rodrigo Javier
學位授予機構：Stanford University
論文連結：
https://www.proquest.com/pqdtglobal/docview/2460651583/
摘要：
A critical step to understanding charge transport in complex systems is being able to characterize them accurately and extensively. In particular, the microstucture of conjugated polymers exhibits a coexistence of ordered and amorphous regions, with the size of the ordered regions being smaller than the length of individual polymer chains.
Taming Reactive Phosphorus Intermediates with Organic and Inorganic Carriers
作者：Velian, Alexandra
學位授予機構：Massachusetts Institute of Technology
論文連結：
https://www.proquest.com/pqdtglobal/docview/1711138798/
摘要：
Complexes (THF)0–2E[P3Nb(ODipp)3] 2 (E = Sn, Pb; Dipp = 2,6-iPr2 C6H3) were prepared and characterized as potential precursors to new tetrel phosphides. Treatment of (THF)Sn[P3Nb(ODipp) 3]2 with pyridine-N-oxide effected the formation of ONb(ODipp) 3(py) and a new tin phosphide, [(THF)SnP6] x, characterized using a multitude of techniques. Additionally, P3Nb(ODipp)2(py)2, prepared from [Na(THF) 3][P3Nb(ODipp)3] in the presence of pyridine and salts of coordinating cations, was found to successfully produce AsP 3 upon treatment with AsCl3.
Protein design: Reengineering of cellular retinol binding protein II (CRBPII) into a rhodopsin mimic, functionalization of CRBPII into a fluorescent protein tag and design of a photoswitchable protein tag
作者：Wang, Wenjing（王文靜）
學位授予機構：Michigan State University
論文連結：
https://www.proquest.com/pqdtglobal/docview/926197871/
摘要：
The intrinsic mechanism for wavelength regulation observed in color rhodopsins has been under intense study since the last century. One single chromophore, retinal, was found to absorb over a wide range of the visible spectrum, from 420 nm to 560 nm, depending on which rhodopsin it is bound to. Different model compound studies, rhodopsin mutagenesis studies and computational studies have been carried out to understand what causes the spectral differences. However, this question is still not conclusively answered, due to lack of crystal structures of the color rhodopsins and rhodopsin mutants. Our lab has engineered a small cellular protein, Cellular Retinoic Acid Binding Protein II, into a rhodopsin mimic that can bind all- trans-retinal as a protonated Schiff base. Further studies demonstrated that full sequestration of the chromophore from the bulk solvent is critical for spectral tuning. Therefore, a second generation rhodopsin mimic using Cellular Retinol Binding Protein II (CRBPII) was engineered and mutagenesis was carried out to study the cause-effect relationships of different stereo-electronic effects on wavelength regulation. We were able to regulate the wavelength over an unprecedented range (474 nm to 644 nm), surpassing the existing limits. Electrostatic calculations based on the high resolution crystal structures of CRBPII mutants revealed that electrostatic interactions are playing the major role in the spectral tuning observed.
RNA epigenetics: RNA methylation as a new mechanism of gene regulation
作者：Wang, Xiao（王瀟）
學位授予機構：The University of Chicago
論文連結：
https://www.proquest.com/pqdtglobal/docview/1722054737/
摘要：
Cells of a multicellular organism share identical DNA sequence, yet their fates and functions diverge substantially. Epigenetics studies chemical reactions and factors that determine cell fates without changing the DNA sequence. Established epigenetic mechanisms involve chemical modifications of DNA and histone proteins. In contrast, RNAs carry numerous chemical modifications whose potential roles in epigenetic processes have not been explored. N6-methyladenosine (m6A) is the most prevalent modification present in the messenger RNA of all higher eukaryotes. This modification is reversible and non-stoichiometric, and adds an additional layer to the dynamic control of mRNA metabolism. We characterized two m 6A reader proteins, human YTHDF1 and YTHDF2, which specifically recognize m6A-modified mRNAs inside the cells. In a unified mechanism of m6A-based gene regulation, YTHDF2 reduces mRNA stability to control the lifetime of target RNAs, whereas, YTHDF1 promotes mRNA translation to ensure effective protein production from short-lived RNAs marked by m 6A. Therefore, the m6A modification in mRNA endows gene expression with fast response and controllable protein production. Such mechanism of gene regulation is found critical during epigenetic processes, e.g. stem cell differentiation and animal development.
Development and Applications of (Hetero)cycloisomerization Methodologies to Access Natural Product Scaffolds
作者：Wilkerson-Hill, SIdney Malik
學位授予機構：University of California, Berkeley
論文連結：
https://www.proquest.com/pqdtglobal/docview/1917409415/
摘要：
The development of new heterocycloisomerization reactions as a tactic to access natural product scaffolds is an active area of research. Chapter 1 describes the development of a new heterocycloisomerization reaction of alkynyl-[4.1.0]-bicycloheptanones using W(CO)5•THF complex to access 4,5-dihydrobenzo[b]-furans and –indoles. Specifically, the methodology developed provides a unique entry into dihydro-benzofurans and –indoles that contain carbon substitution at the C4-position, which is a common motif in many biologically active indole alkaloid natural products (e.g. the ergot alkaloids). The unique reactivity of dihydro-benzofurans and –indoles as it pertains to accessing natural product scaffolds is also described.
Novel analytical and preparative mass spectrometric methodologies in reaction monitoring and acceleration
作者：Yan, Xin
學位授予機構：Purdue University
論文連結：
https://www.proquest.com/pqdtglobal/docview/1881318756/
摘要：
This dissertation explores two roles of limited volume solutions formed by dropcasting or by spray-based ionization processes in mass spectrometry, 1) as microcontainers to allow monitoring of bulk reactions or 2) as microreactors in which to accelerate reactions.
New Reactivity and Selectivity in Transition Metal-Catalyzed C-C and C-N Bond Forming Processes
作者：Yang, Yang（楊揚）
學位授予機構：Massachusetts Institute of Technology
論文連結：
https://www.proquest.com/pqdtglobal/docview/1771642244/
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