Physical Chemistry Commons^™

Impact Of Sample Conditions On Dna Phosphodiester Backbone Bi/Bii Conformational Equilibrium Dynamics, Autumn C. Pilarski

Graduate Theses/Dissertations

DNA damage, such as single base lesions and mismatches, is highly prevalent within cells. If these DNA damage events are not repaired, they could lead to mutations and thus disease and cancer. Intricate repair mechanisms are in place to fix these damage events, one such being Base Excision Repair (BER) and associated enzyme: Thymine DNA Glycosylase (TDG). The first step of this repair process, recognition of the lesion by TDG, is not well understood. The following thesis presents results to better understand the fundamental biophysical question of how a DNA lesion within a mismatch context is recognized in a million …

Exogenous Factors That Impact Huntingtin Aggregation, Adam Skeens

Graduate Theses, Dissertations, and Problem Reports (ETD)

While expansion of a polyglutamine (polyQ) domain is the immediate cause of huntingtin (htt) aggregation associated with Huntington’s Disease (HD), other cellular factors modify aggregation. These include interactions with cellular membranes, protein biding partners, molecular crowding, and proteinaceous seeds. Here, two important factors are biophysically characterized: 1) the interaction of htt with endomembranes and 2) proteinaceous seeds obtained from a variety of htt-derived peptides. In the first project, the aggregation of htt at bilayer interfaces and in the presence of divalent cations was investigated. A major cellular factor implicated in altered htt aggregation is the binding of lipids. Furthermore, the …

Telp Theory: Elucidating The Major Observations Of Rieger Et Al. 2021 In Mitochondria, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

The transmembrane-electrostatically localized protons (TELP) theory may represent a complementary development to Mitchell's chemiosmotic theory. The combination of the two together can now excellently explain the energetics in mitochondria. Our calculated transmembrane-attractive force between an excess proton and an excess hydroxide explains how TELP may stay within a 1-nm thin layer at the liquid-membrane interface. Consequently, any pH sensor (sEcGFP) located at least 2–3 nm away from the membrane surface will not be able to see TELP. This feature as predicted from the TELP model was observed exactly in the experiment of Rieger et al., 2021. In contrast to their …

Food Waste Storage Gaseous Emissions Detection And Quantification Using Infrared Spectroscopy, Ryley A. Burton-Tauzer

Cal Poly Humboldt theses and projects

A growing interest in sustainable waste management and the implementation of new policies have prompted a shift towards alternative resource recovery methods for organic waste, including food waste. To effectively assess alternative food waste treatment scenarios, it is important to evaluate the life cycle impacts associated with each scenario. The storage phase of food waste, encompassing its accumulation in kitchens, and storage in bins for collection and transportation, has been overlooked as a source of greenhouse gases in previous studies. This investigation aimed to identify the greenhouse gases emitted during the initial five-day period of low-oxygen storage. An open dynamic …

Application Of Computational Biophysics Techniques To Characterize Cell Membrane-Associated Events, Kyle Billings

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cell membranes are crowded environments which can modulate protein structure-function relationships through interaction with lipids, other proteins, carbohydrate structures and so on. This work focuses the impact of the membrane environment on two varieties of peptides: Microbial rhodopsin proteins, and cyclic peptides.

Life on Earth is dependent on the ability of plants and microbes to harness sunlight for energy production. Their ability to transform light into carbohydrates requires tailor-made machinery, and for a wealth of microorganisms, microbial rhodopsin proteins (MR) are critical for maintaining the concentration gradients used to produce the energy molecule Adenosine triphosphate (ATP). The central retinal molecule …

Investigation Of Early Complex Formation Of Huntingtin Protein With And Without Lipids, Alyssa R. Stonebraker

Graduate Theses, Dissertations, and Problem Reports (ETD)

Huntington’s disease (HD) is a fatal neurodegenerative disease caused by the expansion of the polyglutamine (polyQ) domain of the huntingtin protein (htt). The expansion of the polyQ domain beyond a threshold of approximately 35 repeats triggers complex toxic aggregation mechanisms and results in altered interactions between htt and lipid membranes. Many factors modulate these processes. One such modulator includes sequences flanking the polyQ domain, most notably the first 17 amino acids at the N-terminus of the protein (Nt17), and environmental factors including the presence of membranous structures. Nt17 has the propensity to form an amphipathic a-helix in the presence of …

Quantum Computations And Molecular Dynamics Simulations: From The Fundamentals Of Antimicrobial Resistance To Neurological Diseases, Angel Tamez

Electronic Theses and Dissertations

Biophysical phenomena are modeled using a combination of quantum and classical methods to interpret and supplement three distinct and diverse problems in this dissertation. In the first project, decarboxylation reactions are ubiquitous across chemical and biological disciplines, yet the origin of non-catalytic solvent effects remains elusive. Specific solvent structure and energetics have not been well described for the monoanion of malonate, nor corrected from the gas-phase charge-assisted intramolecular hydrogen bond model known as “pseudochair”. In the aqueous phase, a low-lying energy conformer known as the “orthogonal conformation” is computed to be preferred by a three-water cluster of hydrogen bonding over …

Estimation Of The Bubble Point Pressure Of Multicomponent Reservoir Hydrocarbon Fluids, Benjamin Sunday Usen, Chidi Obi

Makara Journal of Science

This study developed a novel C-sharp (C#) programming language for the estimation of bubble point pressure (BPP) of various hydrocarbon mixtures at equilibrium state. The methodology was based on vapor–liquid equilibrium calculation using Peng Robinson equation of state implementation, thermodynamic equilibrium calculation and Newton-Raphson’s method for the successive substitution of the unknown variables. The equal fugacity constraint can be satisfied by obtaining the equilibrium which serves as a criterion for two or more phases to exist at equilibrium. The problem was resolved by searching for a pressure that will satisfy the two constraints. Complex calculation was performed by successively substituting …

Mechanism Of Sila- And Germafluorenes For Biological Applications, Shelby Jarrett

Dissertations

2,7-disubstituted silafluorenes and germafluorenes, originally designed for OLED applications, are a class of fluorescent dyes that have gained recent interest as probes for bioimaging and as biosensors to monitor cellular dynamics and interactions. Desirable biological probes absorb in the visible region, have high extinction coefficients, high quantum yield and excellent photostability. Here, their spectral properties are investigated under aqueous conditions for relevant biological applications. These molecules display intense blue fluorescence in the solid state and in solution, have high extinction coefficients, and exhibit appreciable solubility in aqueous solution. To better understand potential applications, the mechanism of fluorescence was investigated. It …

Co-Microencapsulation Of Ruellia Tuberosa L. And Cosmos Caudatus K. Extracts For Pharmaceutical Applications, Choirin Annisa, Sasangka Prasetyawan, Anna Safitri

Makara Journal of Science

This study aims to co-microencapsulate the Ruellia tuberosa L. and Cosmos caudatus K. extracts, with chitosan–sodium tripolyphosphate (Na-TPP) as coating material. α-Amylase inhibition and antioxidant assays were conducted to determine the potential of microcapsules used as antidiabetic agents. The microcapsules were manufactured under the influences of pH, Na-TPP concentration, and stirring time. The optimum microencapsulation conditions were selected based on the highest encapsulation efficiency. The optimum microencapsulation conditions were a pH of 4, Na-TPP concentration of 0.15% (w/v), and stirring time of 60 min. The microcapsules exhibited an IC₅₀ (inhibitory concentration) value of 223.64 ± 0.81 µg/mL and an …

A New Insight Into Fungal Cell Wall Architecture By Functional Genomics And Solid-State Nmr Along With Recent Advancements In Dynamic Nuclear Polarization For Analyzing Biomolecules, Arnab Chakraborty

LSU Master's Theses

This dissertation summarizes the findings related to the way by which supramolecular architecture of fungal cell wall changes with genetic mutation, dispensing genes responsible for biosynthesis of cell wall polysaccharides. This is necessary because without perfect picture of how supramolecular assembly changes with genetic mutation it is hard to assess new anti-fungal targets. Alongside this we have highlighted how recent advancement into Dynamic Nuclear Polarization (DNP) methods improved characterization of biomolecules both in case of labeled and unlabeled samples.

First study utilized Solid-state NMR (SSNMR) which is a non-destructive technique hence enabled us for the first time to deduce how …

Analysis Of The Light Responsive Azobenzene Peptide Nucleic Acid Duplexes, Kat Nguyen

Honors College Theses

Peptide nucleic acids (PNAs) are oligonucleotide analogues in which the sugar-phosphate backbone has been replaced by a pseudopeptide skeleton. Since PNAs use the natural nucleobases (Adenine, Thymine, Cytosine, Uracil, and Guanine) found in either DNA and/or RNA, they are able to hybridize according to Watson-Crick base-pairing to form duplexes. PNA is a promising therapeutic agent because they can function as antigene or antisense chemical agents. To further enhance their utility, we aim to incorporate a photoswitchable moiety using azobenzene. Here, we report the results of the synthesis and purification of a photoswitchable 11 mer PNA along with initial characterization efforts.

Investigation Of The Binding Domain Interfaces Of The C-Terminus Of The Albino3 Insertase And The 43kda Chloroplast Signal Recognition Particle Subunit Via Single Molecule Förster Resonance Energy Transfer, Amanda Tomanek

Chemistry & Biochemistry Undergraduate Honors Theses

Fluorescent labeling is a technique used for visualizing functional groups contained in biomolecules by fluorescence imaging. This technique was used in this project to analyze post-translational targeting of light-harvesting chlorophyll-binding proteins (LHCP), which are the core complexes that harvest sunlight to drive photosynthetic electron transfer. This protein is synthesized in the cytosol and post-translationally targeted to the stroma of chloroplasts. CpSRP43 is a signal recognition particle (SRP) subunit unique to chloroplasts, which has been shown to interact with the stroma-soluble C-terminus of the thylakoid-bound Albino3 insertase (Alb3-Cterm). In the chloroplast stroma, targeting to thylakoids is performed via the cpSRP pathway …

Targeting Platelets Using Ionic Liquid Coated Nanoparticles, Karen Mun Wong

Honors Theses

Platelets are key players in our body’s inflammatory processes upon activation, which can create physiological problems. Researchers are actively seeking solutions by targeting platelets with therapeutics. The objective of the research in this thesis was to investigate a new and potentially less invasive drug delivery platform using nanoparticles. The topic of the project was to explore the world of ionic liquids and their abilities, when coated on nanoparticles, to bind to platelets. A library of choline carboxylic acid-based ionic liquids (ILs) was first synthesized via salt metathesis while PLGA-based nanoparticles were simultaneously being synthesized via the nanoprecipitation method. The ionic …

Synthesis And Characterization Of A Novel Reaction-Based Azaborine Fluorescent Probe Capable Of Selectively Detect Carbon Monoxide Based On Palladium-Mediated Carbonylation Chemistry, Samuel Moore, Carl Jacky Saint-Louis

Symposium of Student Scholars

Azaborines are fascinating compounds because they possess valuable properties such as photochemical stability, have high molar absorption coefficient and high fluorescent quantum yields, as well as large Stokes shifts and tunable absorption/emission spectra. Here, we designed, synthesized, and will examine a novel reaction-based azaborine fluorescent probe capable of selectively detect carbon monoxide (CO) based on palladium-mediated carbonylation chemistry. This novel azaborine fluorescent probe will exhibit high selectivity for CO and display a robust turn-on fluorescent response in the presence of CO in aqueous buffer solution.

Ketal-Azaborine Versus Ketal-Azaborine With A Spacer: Structural Effects On The Photophysical Properties Of Tunable Heteroaromatic Polycyclic Chromophores, Albert Campbell, Janiyah Riley, Samuel Moore, Albert Campbell

Symposium of Student Scholars

Flat-structured heteroaromatic polycyclic compounds with extended conjugated π-systems such as azaborines are in high demand in the material and imaging technology markets because of their unique features such as simultaneous tunability of fluorescence color and intensity. We have designed, synthesized, and investigated a series of novel conjugated thermally stable ketal-azaborine chromophores that contain a phenyl ring as a spacer between electronic moieties and the ketal-azaborine core as easily tunable high-luminescent organic materials. We investigated the impact of the phenyl spacer on the ketal-azaborine unit. We examined the structural effects on their photophysical properties by incorporating electron –donating and –withdrawing substituents …

Azaborine Versus Azaborine With A Spacer: Structural Effects On The Photophysical Properties Of Tunable Azaborine Chromophores, Kaia Ellis, Janiyah Riley, Lyric Gordon, Janiyah Riley

Symposium of Student Scholars

Azaborines are fascinating compounds because of their valuable and interesting optical properties making them suitable to be utilized in many optoelectronic devices. We have designed, synthesized, and investigated a series of novel conjugated thermally stable azaborine chromophores by incorporating a phenyl ring as a spacer linking the chromophore to different electronic moieties as easily tunable high-luminescent organic materials. We investigated the effect of the phenyl spacer on the azaborine unit. The substituent effects of different electronic moieties were investigated by the insertion of electron –withdrawing and –donating moieties to the phenyl spacer. We examined the role of the electron –donating …

Affinity Of Cadmium Versus Zinc For The Carbonic Anhydrase Active Site, Rachel Phan

Honors Scholars Collaborative Projects

Cadmium is a heavy metal found in tobacco plants, nickel-cadmium batteries, and as a byproduct of metal mining. The similarities between the properties of zinc ions and cadmium ions in proteins due to their 2+ charges may cause displacement of zinc by cadmium if encountered and has been shown to do so in several transcription factors. Cadmium’s ability to replace zinc- a metal found in around 3,000 human proteins- is a cause for concern, especially due to its toxicity, long half-life in the body, and larger size.

Carbonic anhydrase is an important metalloprotein protein that relies on a central zinc(II) …

The Photo-Transformation Of Free Methionine In The Presence Of Surrogate And Standard Isolate Dissolved Organic Matter Under Sunlit Irradiation, Benjamin J. Mohrhardt

Dissertations, Master's Theses and Master's Reports

Sulfur (S)-containing amino acids are key sources of carbon, nitrogen, and sulfur involved in protein synthesis, protein function, and providing energy for microbial growth. Dissolved free and combined methionine is one of two S-containing amino acids incorporated into proteins and has been attributed to their stability and function. The oxidation of methionine has received considerable attention given its ubiquitous presence in most biological systems and has been associated with losses in protein function and pathological disorders. In natural waters, methionine is rapidly and selectively taken up by microorganisms to achieve cellular requirements of carbon, nitrogen, and sulfur. The abiotic transformation …

Here, There, And Everywhere: Probing Ubiquitin-Cavitand Binding Via 15n-1h Hsqc, Julia Didziulis

Scripps Senior Theses

Ubiquitination and other post-translational modifications play a major role in the proliferation of many neurodegenerative diseases, developmental disorders, and cancers, and as such are subjects of recently increased biochemical interest. Expanding upon such research, this study confirmed a robust method of ubiquitin expression and purification, then used 15N-1H HSQC to analyze ubiquitin samples containing varying concentrations of a deep cavitand with affinity for lysine and arginine side chains. In the pure ubiquitin spectrum, arginine side chain chemical shifts were detected in the nitrogen 80-85 ppm range and lysine side chain signals were undetected. However, upon introduction of the cavitand, collection …

Seasonal Flammability Comparisons Of Native And Exotic Plants In The Post Oak Savannah, Blackland Prairie, And Pineywoods Ecoregions Of Texas, Michael Tiller

Electronic Theses and Dissertations

East Texas’ diverse landscape can present year-round wildfire seasons that can be influenced by seasonal and regional differences in climate and physiography. Greater insight into the fundamental thermal behavior of wildland fuels can aid in fire behavior prediction and development of fire-resistant plant lists. This study focused on estimating seasonal and regional flammability characteristics of five evergreen species: yaupon (Ilex vomitoria), Chinese privet (Ligustrum sinense), greenbrier (Smilax spp.), eastern red cedar (Juniperus virginiana), and escarpment live oak (Quercus fusiformis); and two deciduous species: Chinese tallow (Triadica sebifera) and southern …

Investigations Of Elastin Recoil On Molecular And Macroscopic Levels., Nour Mohammad Jamhawi

Electronic Theses and Dissertations

Elastin is one of the most hydrophobic proteins, and it is extremely flexible when hydrated. The driving force for recoil is the decrease in entropy of the protein and/or the hydrating solvent. This dissertation is a study of both mechanisms. Following an introduction (Chapter 1), Chapters 2 and 3 investigate the recoil mechanism on the molecular level in the hydrating solvent and in the protein, respectively. Chapter 4 examines macroscopic properties of recoil by thermomechanics. Conclusions are discussed in Chapter 5. Using double quantum NMR, the deuterated water ordering at the elastin surface was studied quantitatively as a function of …

Bridging The 12-6-4 Model And The Fluctuating Charge Model, Pengfei Li

Chemistry: Faculty Publications and Other Works

Metal ions play important roles in various biological systems. Molecular dynamics (MD) using classical force field has become a popular research tool to study biological systems at the atomic level. However, meaningful MD simulations require reliable models and parameters. Previously we showed that the 12-6 Lennard-Jones nonbonded model for ions could not reproduce the experimental hydration free energy (HFE) and ion-oxygen distance (IOD) values simultaneously when ion has a charge of +2 or higher. We discussed that this deficiency arises from the overlook of the ion-induced dipole interaction in the 12-6 model, and this term is proportional to 1/r …

Awegnn: Auto-Parametrized Weighted Element-Specific Graph Neural Networks For Molecules., Timothy Szocinski, Duc Duy Nguyen, Guo-Wei Wei

Mathematics Faculty Publications

While automated feature extraction has had tremendous success in many deep learning algorithms for image analysis and natural language processing, it does not work well for data involving complex internal structures, such as molecules. Data representations via advanced mathematics, including algebraic topology, differential geometry, and graph theory, have demonstrated superiority in a variety of biomolecular applications, however, their performance is often dependent on manual parametrization. This work introduces the auto-parametrized weighted element-specific graph neural network, dubbed AweGNN, to overcome the obstacle of this tedious parametrization process while also being a suitable technique for automated feature extraction on these internally complex …

Mechanisms Of Spontaneous Curvature Inversion In Compressed Graphene Ripples For Energy Harvesting Applications Via Molecular Dynamics Simulations, James M. Mangum, Ferdinand Harerimana, Millicent N. Gikunda, Paul M. Thibado

Physics Faculty Publications and Presentations

Electrically conductive, highly flexible graphene membranes hold great promise for harvesting energy from ambient vibrations. For this study, we built numerous three-dimensional graphene ripples, with each featuring a different amount of compression, and performed molecular dynamics simulations at elevated temperatures. These ripples have a convex cosine shape, then spontaneously invert their curvature to concave. The average time between inversion events increases with compression. We use this to determine how the energy barrier height depends on strain. A typical convex-to-concave curvature inversion process begins when the ripple’s maximum shifts sideways from the normal central position toward the fixed outer edge. The …

Computational Modeling Of Water And Proteins In Drug Discovery, Anthony Cruz Balberdy

Dissertations, Theses, and Capstone Projects

This thesis aims to improve how structural and thermodynamic properties of water on protein surfaces can be exploited to aid early stage drug discovery and lead optimization. We first discuss our development of SSTMap, a public domain software suite that maps out the properties of water on biomolecular surfaces. We then show the utility of these maps in describing differences in binding affinities between congeneric pairs of ligands. We then discuss our use of solvation maps in the prospective discovery of novel binders to cytochrome C peroxidase. Finally, we present our creation and validation of a homology model of Interleukin-24 …

High Performance Mixed-Matrix Electrospun Membranes For Ammonium Removal From Wastewaters, Shu-Ting Chen, Sumith Ranil Wickramasinghe, Xianghong Qian

Chemical Engineering Faculty Publications and Presentations

Mixed-matrix electrospun membranes were developed to investigate ammonium removal from low ammonium concentration wastewaters for the first time. Particles derived from the inexpensive zeolite 13X were successfully incorporated into polyethersulfone (PES) matrices. The fabricated mixed-matrix electrospun membranes demonstrate high ammonium removal capacity reaching over 55 mg/g_zeolite, more than 2.5 times higher than the previously fabricated mixed-matrix membranes via non-solvent induced phase inversion. Moreover, the membranes fabricated exhibit high permeability and ease of regeneration. Over 90% of total ammonium nitrogen (TAN) can be removed from low TAN wastewaters such as aquaculture wastewaters. In addition to zeolite 13X, other zeolite …

The Effect Of The Apolipoprotein A1 (Apoa1): The Stability And Folding In Potassium Chloride Environment, Alexandra Paladian

Honors Theses

Healthy levels of potassium chloride (KCl) can significantly affect the workings of the cholesterol level of the human body and how they pertain to an individual person. The search for a better salt additive for the human diet can provide a better option for people who experience high cholesterol levels and heart disease. The study focuses on the experimental design of the Molecular Dynamic (MD) simulation of the Apolipoprotein A1 (APOA1) in the potassium ion solution environment to determine the stability and folding of the protein. The study also compares its data to the previous experimental design of chloride ions …

Molecular Dynamic Simulation Of The Complex Folding Patterns Of Apolipoprotein A1 In Various Concentrations Of Potassium Chloride, Hannah Holmberg

Honors Theses

Apopliprotein or ApoA-1 is a complex lipoprotein that functions in the removal of cholesterol from the blood, removing cholesterol from the area around white blood cells and promoting the excretion of lipids through the lymphatic system. Previous research has found that ApoA-1 shows both folded and unfolded conformations depending on the concentration of NaCl in solution in the water around it. The protein was studied using molecular dynamics simulations. Once this state of equilibrium was reached, various structural properties of the protein were measured including the radius of gyration and the radial distribution function. The goal of the project was …

Remote Performance Modulation Of Ultrafiltration Membranes By Magnetically And Thermally Responsive Polymer Chains, Arijit Sengupta, Anh Vu, Xianghong Qian, Sumith R. Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

Ultrafiltration membranes, that respond to an external magnetic field and local temperature have been developed. Surface-initiated activator-generated electron transfer (AGET) atom transfer radical polymerization (ATRP) has been used to graft poly(N-isopropylacrylamide) (PNIPAm) from the surface of 300 kDa regenerated cellulose membranes. The polymerization initiator was selectively attached to the entire membrane surface, only the outer membrane surface or only the inner pore surface. A superparamagnetic nanoparticle was attached to the end of the polymer chain. The DI water flux as well as the flux and rejection of bovine serum albumin were investigated in the absence and presence of a 20 …