Organizational Unit:

School of Chemistry and Biochemistry

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https://hdl.handle.net/1853/70752

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College of Sciences

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https://finding-aids.library.gatech.edu/agents/corporate_entities/153

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Publication Search Results

Now showing 1 - 10 of 411

Interlaboratory Comparison of a Complex Targeted Assay: Improving Consistency and Reliability in Metabolomics Analyses

(Georgia Institute of Technology, 2023-12-07) Phillips, Emily R.

Ideal isotope-labeled internal standards for analysis via targeted metabolomics approaches are presented for negative and positive ion modes for both hydrophilic interaction liquid chromatography (HILIC) and reverse phase liquid chromatography (RPLC) chromatography coupled to mass spectrometry. These best performing analytes (BPA) were deduced after experimentation from a collaborative research project involving six top metabolomics research laboratories in the country. These results are detailed in this work, supported by observed behaviors of included chemical classes and chromatographic behaviors, and align with the group hypothesis and expectations
The Role of Space Weather in Forming Water from the Potential Lunar Regolith Simulant Rhyolite

(Georgia Institute of Technology, 2022-08-26) Castarlenas, Aintzane

The potential role of the solar wind and space weathering in the formation of water on a lunar surface has been studied by deuteron ion implantation followed by electron bombardment on a silica rich glass surrogate, rhyolite. The electron bombardment stimulates chemistry and leads to water formation and ion desorption. The latter process, electron stimulated desorption (ESD) probes the role of electrons from the solar wind in both producing and desorbing ionic and neutral products. Prolonged electron excitation of deuteron dosed rhyolite samples induces defects on the sample, opening paths for diffusion of molecules to the surface. These experiments lead to the conclusion that solar wind in conjunction with electron bombardment of the lunar soil can generate water and other volatile products such as molecular hydrogen. These processes should be considered when modeling the lunar hydrogen and water pathways or cycles.
Synthesis and Characterization of Imidophosphorane Ligand Derivatives For Crystalline, Low Coordinate F-Element Complexes

(Georgia Institute of Technology, 2022-08-03) Tateyama, Haruko

This thesis describes the development of imidophosphorane ligand derivatives in order to access low coordinate, crystalline complexes of lanthanides and actinides. Chapter 1 provides a general overview of the low-coordinate f-block complexes and ligands used in achieving such systems. Chapter 2 describes the synthesis of four imidophosphorane ligand derivatives, including synthetic challenges encountered. These ligand derivatives were developed to address synthetic challenges of limited solubility and crystallinity from the ligand developed in the group. The availability of these four ligand derivatives will give us a toolbox of ligands in addressing such synthetic challenges, eventually with the goal of accessing low-coordinate, crystalline f-element complexes. Chapter 3 showcases the crystallographic analyses of the four imidophosphorane derivatives.
Homopolymer and block polymer materials derived from highly reactive thionolactone monomers

(Georgia Institute of Technology, 2022-05-03) Tennyson, Simone Lena

Thionolactones are a recently discovered sub-class of radical ring-opening monomers that are notable for their ability to impart labile thioester units into polymer backbones when used as a comonomer. The simple scaffold allows for structural changes to further tune the monomer’s reactivity in order to change rates of copolymerization with different monomer families and can even lead to systems capable of homopolymerization. Thionolactones also demonstrate high degrees of control with reversible addition-fragmentation chain-transfer (RAFT) polymerizations, and rapid reactivity with acrylates. In this thesis, the introduction of the furan heterocycle into a 7-membered thionolactone monomer scaffold is described, and the resulting homopolymerization behavior is studied (Chapter 2). Additionally, a thermally responsive amphiphilic diblock polymer of N,N-dimethylacrylamide and N-isopropylacrylamide with a cleavable thioester junction is prepared using a new 6-membered thionolactone derivative with ultra-fast copolymerization behavior (Chapter 3).
Expression, Purification, and Activity of Putative Intramembrane Aspartyl Proteases From Diverse Species

(Georgia Institute of Technology, 2022-04-27) Thomas, Gwendell Michelle

Intramembrane aspartyl proteases (IAPs) cleave peptide bonds within the hydrophobic lipid membrane. The best characterized IAP is presenilin, the catalytic subunit of γ-Secretase, which is known for cleaving amyloid precursor protein into the amyloid-β peptide that aggregates in the brains of Alzheimer’s patients. More than 100 substrates have been documented for γ-Secretase, yet no consensus recognition sequence has emerged, at least in part due to the technical complexities of studying this membrane-embedded proteolytic system. To date, the presenilin homolog from Methanoculleus marisnigri JR1 (MCMJR1) has been the sole microbial model of non-eukaryotic IAPs for in vitro molecular studies. A recent bioinformatic study uncovered over 1000 putative IAP sequences lurking in archaeal and bacterial organisms. Here, we report recombinant expression, purification, and enzymatic activity of selected new IAPs. These new IAPs express well and are from noted archaea such as H. volcanii and Lokiarchaeota. These putative IAP orthologs share key structural and cleavage preference similarities with MCMJR1 IAP and presenilin. By studying the molecular biochemistry of more IAP family members, additional trends and insights regarding cleavage preferences and peculiarities will emerge. Such knowledge will further illuminate the fascinating fundamental and complex chemistry occurring within the lipid membrane.
PEG (Polyethylene Glycol)-PCL (Polycaprolactone) Block Copolymers For 3D Printing Of Medical Devices

(Georgia Institute of Technology, 2022-01-18) Yang, Ruyi

PCL polymers have been widely used in 3D printing of scaffolds over the past few decades, which can be applied in a variety of medical devices. However, PCL has intrinsic defects, such as high hydrophilicity which causes low biocompatibility. The research reported in this thesis aims to modify existing PCL polymers by developing a series of PEG-PCL block copolymers with different ratios of blocks and investigate their potential as implants for soft tissue engineering and airway reconstruction. The introduction of PEG blocks to PCL enhanced biocompatibility towards mammalian cells compared to the commercially available PCL with same molecular weight, without compromising the 3D printability. Moreover, some PEG-PCL copolymers showed significantly better resistance towards bacterial adhesion, which is desirable for both applications. The various mechanical properties of these copolymers make them promising candidates to devise patient-specific medical devices with various needs.
Analysis of Adenosine Triphosphate in Spatially Distributed Planetary Analog Field Samples to Inform Biosignature Detection Missions

(Georgia Institute of Technology, 2021-05-11) Novak, Carlie Marie

New discoveries of potentially habitable environments elsewhere in our solar system, and at the extremes here on Earth, have reopened the imagination to possibilities for extraterrestrial life. Planetary field analog research enables us to study the impact of similar extreme environmental stressors and the bioactivity of an ecosystem. This thesis research was designed to better understand biosignature detection in extreme environments by exploring distributions and patterns of biosignatures in harsh planetary environments. Adenosine triphosphate (ATP) was used as a proxy of bioactivity due to its ubiquitous role in terrestrial metabolism and can be quantified easily by a bioluminescence assay. Observing variations in concentrations of ATP can provide insight on where bioactivity becomes concentrated, or evenly distributed which is essential in the search for life outside of Earth. A variety of chemical and physical studies of samples from analog locations aids in understanding the limits of life terrestrially, and therefore can help make more informed predictions about the potential habitability on other planetary bodies.
Lipid Biomarker Alterations Following Mild Traumatic Brain Injury

(Georgia Institute of Technology, 2021-01-22) Gier, Eric C.

The work presented in this thesis highlights the current state of biomarker research for traumatic brain injury (TBI) and seeks to investigate the potential of novel lipid biomarkers for TBI. Awareness and research interest surrounding TBI have been heightened in recent years due to increased media coverage and epidemics within the military, athletic organizations, accident victims, the elderly, and the general population. The heterogeneous nature of TBI makes diagnosis and biomarker discovery particularly challenging as severities and exposure events vary widely. The first two chapters serve to outline the current state of TBI regarding its impact on human life, methods of diagnosis, injury mechanisms, and current research in the field. These chapters ultimately highlight a current gap between modern research and clinical implementation that is being closed rapidly through omics research. The final two chapters describe the research conducted over the past year to identify potential lipid biomarkers of TBI. Two predictive lipid panels were developed to classify injured and uninjured Sprague-Dawley rat serum across two injury severities and three acute postinjury timepoints. Identified lipid features from the proposed panels consist primarily of phosphatidylcholine and triacylglyceride species which warrant future investigation as proposed biomarkers of TBI. Ultimately, future work is needed to validate the features identified as potential biomarker candidates and to connect the lipid responses discovered in serum to alterations in the brain lipid profile to gain a more holistic picture of TBI.
PARSIMONIOUS ALGORITHMS AND IMPLEMENTATION IN QUANTUM CHEMISTRY

(Georgia Institute of Technology, 2020-12-07) O'Brien, Joseph Senan

The fundamental crux affecting the performance of quantum chemistry calculations is the need to cover a large number of terms in a way that may entail managing a large amount of data. The costs in time and storage associated with these methods can be mitigated in numerous ways: judiciously exclude insignificant terms, reformulate terms in ways that avoid computing some intermediates, and avoid full formulation of intermediaries. This thesis explores such efforts by examining a direct Density Fitted Coulomb and Exchange (JK) formation algorithm, application of numerous advances in JK construction to Hybrid DFT calculations, reformulation of Coulomb terms to avoid ERI calculations, and parsimonious formation of Coulomb and exchange matrices with different row and column bases under the density fitting approximation.
PSBO SAMPLES A COMPLEX CONFORMATIONAL LANDSCAPE WHICH IS REGULATED BY PHOTOSYSTEM II

(Georgia Institute of Technology, 2020-07-27) He, Jiayuan

The maintenance of aerobic heterotrophic life relies on the photosynthetic oxygen production in the PSII reaction center. This reaction is intrinsically important in biological chemistry. Moreover, the efficiency of transferring solar energy to chemical energy makes PSII an excellent candidate for modeling the design and development of sustainable and biomimetic forms of artificial energy. PSII is a multisubunit transmembrane complex. It consists of several membrane-spanning helices and three main extrinsic subunits. PsbO is proposed to be an IDP when isolated free in solution. Its secondary structure showed significant change after bound to PSII, which is referred as templating effect. MS, CD and UVRR are used in my study to locate the residues that respond to the regulation of PSII. The current work provides new structural/conformational information concerning an indispensable part of the photosynthetic oxygen production reaction, PsbO, an extrinsic subunit of PSII.