Digital Commons Network^™

Influence Of Side Chain Conformation On The Mechanism(S) Of Glycosylation Reactions; Investigation Of Sialidation Reaction Mechanism(S) By Kinetic Studies, Harsha Chandhana Amarasekara

Wayne State University Dissertations

Glycosylation, being the key reaction of glycobiology and carbohydrate chemistry, demands robust and stereoselective glycosylation methods. The rational development of such methods necessitates knowledge of the glycosylation reaction mechanism and the factors influencing glycosylation reactions. The work discussed in this dissertation is focused on studying glycosylation reaction mechanisms and exploring the key factors influencing them.

Chapter one reviews the background to the research, starting with a brief introduction of the significance of carbohydrates as structural and energy-storage materials. The significance of cell surface carbohydrates and their roles in communication and related processes are discussed along with examples of their applications …

Harnessing The Reactivity Of The N-Methyl Diaminobenzoyl Linker To Access C-Terminally Modified And Macrocyclic Peptides, Christine Arbour

Wayne State University Dissertations

This thesis describes the exploration of accessing C-terminally modified and macrocyclic peptides through N-acyl urea (MeNbz) displacement. Prior to this work, the diaminobenzoyl linker was used to access thioesters for native chemical ligation. Only solution-phase displacement of the N-acyl urea with thiol nucleophiles was previously reported.

The N-Me-diaminobenzoyl (MeDbz) linker was initially used to access C-terminal glycine esters, amides, and acids from a single peptide substrate. This led to the total synthesis of Conopressin G and two analogs. The propensity of the C-terminal cysteine residue to undergo epimerization was investigated using this strategy. After optimization, C-terminal cysteine esters, amides, and …

Binary And Ternary Transition Metal Pnictide Nanoparticles And Their Three-Dimensional Assemblies: Towards Promising Magnetic Refrigeration Materials, Malsha Anuradhi Hettiarachchi

Wayne State University Dissertations

BINARY AND TERNARY TRANSITION METAL PNICTIDES NANOPARTICLES AND THEIR THREE DIMENSIONAL ASSEMBLIES: TOWARDS PROMISING MAGNETIC REFRIGERATION MATERIALS

by

MALSHA ANURADHI HETTIARACHCHI

May 2019

Advisor: Dr. Stephanie L. Brock

Major : Chemistry

Degree : Doctor of Philosophy

Bulk MnAs has been recognized as a potential MR material with large MCE. However, the magnetic transition of bulk MnAs suffers from a large thermal hysteresis of 6 K precluding efficient MR cycling, and the magnetic entropy change associated with the phase transition is limited to a narrow temperature range, making the temperature control window very small. Solid solutions of MnAs, synthesized by both …

Atomic Layer Deposition (Ald) And Atomic Layer Etching (Ale) Of Thin Films: Synthesis And Characterization Of A New Class Of Ald Precursors, Ald Of Pralo3 Thin Films, And Thermal Ale Of Cobalt Metal Films, Wathsala Lakmali Iwadunna Waduge

Wayne State University Dissertations

ABSTRACT

ATOMIC LAYER DEPOSITION (ALD) AND ATOMIC LAYER ETCHING (ALE) OF THIN FILMS: SYNTHESIS AND CHARACTERIZATION OF A NEW CLASS OF ALD PRECURSORS, ALD OF PrAlO3 THIN FILMS, AND THERMAL ALE OF COBALT METAL FILMS

by

WATHSALA LAKMALI IWADUNNA WADUGE

February 2019

Advisor: Professor Charles H. Winter

Major: Chemistry (Inorganic)

Degree: Doctor of Philosophy

ALD is an attractive thin film deposition technique due to its unique self-limiting growth behavior and the ability to achieve Angstrom level thickness control. Alternative thin film deposition techniques such as CVD and PVD are unable to attain the conformal and Angstrom level film growth which …

Rare-Earth-Activated Group Vi D0 Metal Oxides As Thermosensitive Phosphors, Samarage Sameera Perera

Wayne State University Dissertations

ABSTRACT

RARE-EARTH-ACTIVATED GROUP VI d0 METAL OXIDES AS

THERMOSENSITIVE PHOSPHORS

by

SAMARAGE SAMEERA PRASAD PERERA

AUGUST 2019

Advisor: Dr. Federico A. Rabuffetti

Major: Chemistry

Degree: Doctor of Philosophy

Thermosensitive phosphors are solid-state materials that demonstrate distinct dependence of luminescence emission on temperature. These materials enable optical temperature sensing in environments where conventional thermometry is not possible (e.g., gas turbines, combustion engines, surface temperature distributions). However, the design of thermosensitive phosphors that show adequate sensitivity and low thermal quenching in the intermediate temperature range (i.e., 500–1000 K) remains challenging. This challenge can be addressed by understanding how to rationally manipulate the …

The Dynamic Nature And Biophysical Characterization Of Isu1, Fe-S Cluster Assembly Scaffold Protein In Saccharomyces Cerevisiae, And Its Significance To Human Disease, Brianne Elizabeth Lewis

Wayne State University Dissertations

Mitochondrial Fe-S cluster biosynthesis is accomplished within yeast utilizing the biophysical characteristics of the “Isu1” scaffold protein. As a member of a highly homologous protein family, Isu1 has sequence conservation with orthologs and a conserved ability to assemble [2Fe-2S] clusters. Regardless of species, scaffold orthologs can exist in both “disordered” and “structured” conformations and is directly related to conformations utilized during Fe-cofactor assembly. During assembly, the scaffold directs the delivery and the utilization of both Fe(II) and sulfide substrates in order to produce [2Fe-2S] clusters, however Zn(II) binding can alter the activity of the scaffold with stabilizing the protein in …

Modification Of Bruker Amazon Etd And Solarix Mass Spectrometers Towards Infrared Multiple Photon Dissociation: Structural Characterization Of Modified Nucleosides, Lucas Ash Hamlow

Wayne State University Dissertations

Infrared ion spectroscopy has become an increasingly powerful tool for examining

the intrinsic structures of gas-phase ions. Infrared multiple photon dissociation (IRMPD)

action spectroscopy has been particularly successful. Several free electron laser (FEL)

facilities across the world have helped facilitate the growth of the IRMPD technique and

increasing interest has driven the development of more accessible IRMPD

instrumentation. The development of one such IRMPD instrumentation system is

described in this work, based around commercially available 3D quadrupole ion trap mass

spectrometers and Fourier-transform ion cyclotron resonance mass spectrometers.

The intrinsic gas-phase structures of nucleic acid monomers have been

extensively studied …

Nonadiabatic Dynamics: A Semiclassical Approach, Ruixi Wang

Wayne State University Dissertations

Nonadiabatic dynamics has been an essential part of quantum chemistry since the 1930’s. Nonadiabatic effects play a crucial role in photo-physical and photo-chemical reactions for both small and large molecules in both gas and condensed phases. Modeling dynamics of photoinduced reactions has been a new frontier of chemistry. Many dynamical phenomena, such as intersystem crossing, non-radiative relaxation, and charge energy transfer, require a nonadiabatic description which incorporates transitions between electronic states.

In Chapter 2, the property of scattering region in the semiclassical limit is investigated. We suggest that a nuclear wavepacket close enough to the conical intersection will propagate ballistically …

Synthesis, Structure, And Luminescence Properties Of Rare-Earth-Doped Alkaline-Earth Fluorohalide Upconverting Nanocrystals, Kumuduni Tauni Dissanayake

Wayne State University Dissertations

The major scientific problems that associated with the state-of-the-art upconverting nanocrystal system (rare-earth-doped β-NaYF4) are lower quantum efficiency, lack of full-spectrum color tunability, and difficulty in achieving single-band red emission. The major scientific strategies that employed to address these scientific problems are based on nanostructuring, tuning rare-earth concentration, and tuning host chemical composition. The reported articles during the past few decades clearly illustrated that nanostructuring and tuning rare-earth concentration hadn’t bought considerable contribution to synthesize efficient and color-tunable upconverting nanocrystal systems. However, the ability to tune the chemical composition of the host to design efficient and color-tunable upconverting nanocrystal system …

Solvent Effects And Charge Transfer States In Organic Photovoltaics, Kangmin Liu

Wayne State University Dissertations

Due to their various advantages, including lightweight, flexible, and cheap manufacturing, organic photovoltaic materials have gained enormous research interest. Over nearly two decades, the power conversion efficiency of organic solar devices has increased dramatically. However, it is still low compared to traditional inorganic semiconductors. In order to improve efficiency, a better understanding of the basic thermodynamic properties of the light-to-electricity power conversion process is needed. One nontrivial aspect of organic solar cells is the low dielectric constant, which leads to tightly-bound excitons upon vertical excitations. The separation of electron-hole pairs requires a larger driving force to overcome the Coulombic binding …

Functional Characterization Of Accessory Proteins And Novel Activities In Direct And Indirect Trna Aminoacylation, Udumbara Menike Rathnayake

Wayne State University Dissertations

Indirect tRNA aminoacylation is essential for most bacteria and archaea, particularly when these species do not have genes encoding asparaginyl- and/or glutaminyl-tRNA synthetase (AsnRS and GlnRS). In the absence of AsnRS, the first step in Asn-tRNAAsn synthesis involves misacylation of tRNAAsn with aspartate to produce Asp-tRNAAsn; this reaction is catalyzed by a non-discriminating aspartyl-tRNA synthetase (ND-AspRS). Subsequently, in bacteria, an amidotransferase called GatCAB converts Asp-tRNAAsn to Asn-tRNAAsn. An analogous, two-step processes exist to produce Gln-tRNAGln. In this case, a non-discriminating glutamyl-tRNA synthetase (ND-GluRS) misacylates tRNAGln to produce Glu-tRNAGln, which is then converted to Gln-tRNAGln by GatCAB. The central hub of …