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2023

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Articles 751 - 780 of 1539

Full-Text Articles in Chemistry

Isolating The Electronic Effects Of Systematic Twist In Highly Substituted Aromatic Hydrocarbons Using Density Functional Theory, Grace Tully, Emily A. Jarvis May 2023

Isolating The Electronic Effects Of Systematic Twist In Highly Substituted Aromatic Hydrocarbons Using Density Functional Theory, Grace Tully, Emily A. Jarvis

Honors Thesis

Density functional theory (DFT) was employed to investigate dodecaphenyltetracene as well as similar molecules containing differing backbone lengths and electron withdrawing groups with interest in manipulating the twist to lower the LUMO level for increased electron mobility. Optimization and frequency time-independent calculations followed by time-dependent (TD-DFT) energy calculations were performed at the B3LYP/G-311G level of theory to analyze electronic trends as a result of increased backbone length and consequently distorted end-to-end molecular twist. These calculations demonstrate a linear relationship with negative slope between the estimated HOMO-LUMO, fundamental, and optical gaps as a function of the number of fused rings along …

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Microwave Regeneration And Thermal And Oxidative Stability Of Imidazolium Cyanopyrrolide Ionic Liquid For Direct Air Capture Of Carbon Dioxide, Yun-Yang Lee, Eda Cagli, Aidan Klemm, Ruth Dikki May 2023

Microwave Regeneration And Thermal And Oxidative Stability Of Imidazolium Cyanopyrrolide Ionic Liquid For Direct Air Capture Of Carbon Dioxide, Yun-Yang Lee, Eda Cagli, Aidan Klemm, Ruth Dikki

Faculty Scholarship

Understanding the oxidative and thermal degradation of CO2 sorbents is essential for assessing long-term sorbent stability in direct air capture (DAC). The potential degradation pathway of imidazolium cyanopyrrolide, an ionic liquid (IL) functionalized for superior CO2 capacity and selectivity, is evaluated under accelerated degradation conditions to elucidate the secondary reactions that can occur during repetitive absorption-desorption thermal-swing cycles. The combined analysis from various spectroscopic, chromatographic, and thermal gravimetric measurements indicated that radical and SN2 mechanisms in degradation are encouraged by the nucleophilicity of the anion. Thickening of the liquid and gas evolution are accompanied by 50 % reduction in CO2 …

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Improvements To Isru For Rocket Fuel Generation, Justin Sharp May 2023

Improvements To Isru For Rocket Fuel Generation, Justin Sharp

James Madison Undergraduate Research Journal (JMURJ)

The development of efficient in-situ resource utilization (ISRU) technologies is crucial for the establishment of an extraterrestrial, self-sustaining colony. The generation of rocket fuel at potential colony locations is necessary to provide the transportation of people and cargo to and from these locations.Three processes are discussed for the improvement of ISRU methods to generate rocket fuel: electrolysis and electrochemical improvements to the process of crude fuel production, physical and chemical methods for separation of gaseous H2 and O2, and materials and cryogenics engineering for storage and transportation of liquid hydrogen (LH2) and liquid oxygen (LOX). Storage and transportation of cryogenics …

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Biosynthesis Of Copper Nanoparticles Using Hylocereus Costaricensis Peel Extract And Their Photocatalytic Properties, Suriati Eka Putri, Netti Herawati, Ahmad Fudhail, Diana Eka Pratiwi, Sumiati Side, Abd Rahman, Susilo Sudarman Desa, Nur Ahmad, Subaer Junaedi, A. Surleva May 2023

Biosynthesis Of Copper Nanoparticles Using Hylocereus Costaricensis Peel Extract And Their Photocatalytic Properties, Suriati Eka Putri, Netti Herawati, Ahmad Fudhail, Diana Eka Pratiwi, Sumiati Side, Abd Rahman, Susilo Sudarman Desa, Nur Ahmad, Subaer Junaedi, A. Surleva

Karbala International Journal of Modern Science

A green chemistry method was used for the first time to synthesize copper nanoparticles (Cu-NPs) using CuSO4 as a precursor and red dragon fruit (Hylocereus costaricensis) peel wasted extract as a bio-reductor. Cu-NPs produced were then used as a photocatalysts for acid orange 7 (AO7) dyes degradation. The results showed that the smallest average crystallite size of the products ranged from 8.84 - 8.86 nm, and the FCC crystal structure had a surface area of 244.38-278.85 m2g-1. Furthermore, the optimum degradation of AO7 dye occurred at a ratio of 1:3 with a percentage of 81.07% for four cycles. These findings …

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Assessing The Possibility And Properties Of Types I And Ii Chalcogen Bonds, Steve Scheiner May 2023

Assessing The Possibility And Properties Of Types I And Ii Chalcogen Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Type I and II halogen bonds are well-recognized motifs that commonly occur within crystals. Quantum calculations are applied to examine whether such geometries might occur in their closely related chalcogen bond cousins. Homodimers are constructed of the R1R2C=Y and R1R2Y monomers, wherein Y represents a chalcogen atom, S, Se, or Te; R1 and R2 refer to either H or F. A Type II (T2) geometry wherein the lone pair of one Y is closely aligned with a σ-hole of its partner represents a stable arrangement for all except YH2, although not all such structures are true minima. The symmetric T1 …

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Surface Enhanced Raman Scattering-Based Multiplexing Detection Of Proteins In Solutions, Hallie Feldman May 2023

Surface Enhanced Raman Scattering-Based Multiplexing Detection Of Proteins In Solutions, Hallie Feldman

Undergraduate Honors Theses

The Influenza virus infected over 36 million people in 2019, whereas the COVID-19
virus caused a deadly pandemic that has infected over 700 million people to date. Both viruses share a magnitude of similar symptoms, which presents a key challenge for the need of a highly sensitive and selective biosensors that can simultaneously detect the specific biomarkers for each of these viruses. This work focuses on developing a Surface-enhanced Raman scattering (SERS) based biosensor for detecting protein biomarkers related to the two viruses such as H1N1 and S- protein. Gold nanoparticles are used for SERS signal amplification. The objective of …

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Photodynamic Therapy Agents: The Power Of Mjöllnir To Eradicate Cancer, Sidney M. Hopper May 2023

Photodynamic Therapy Agents: The Power Of Mjöllnir To Eradicate Cancer, Sidney M. Hopper

Honors College Theses

After its discovery back in the 1900s, photosensitizers became a critical study for potential treatments and cures for medical issues, including cancer. It was discovered that porphyrins appeared to target and accumulate in proliferating cells, and to reach the cells, a certain wavelength of light with maximum absorbance associated with the porphyrin was necessary to achieve cell death. Photodynamic therapy involves making use of porphyrins or metalloporphyrins as activators when exposed to such light. When activated, these compounds generate reactive oxygen species (ROS), such as HO- or O2-, which can react with nucleic acids found in DNA and RNA. In …

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Studying Competing Reaction Pathways In Methanol Decomposition On Platinum Catalysts Under Ultra-High Vacuum (Uhv) Conditions Using Tpd And Sfg Spectroscopy, Quy Loi, Kevin Alvorado Jimenez, Sarah Lelea, Lauren Villegas, Jerry Larue May 2023

Studying Competing Reaction Pathways In Methanol Decomposition On Platinum Catalysts Under Ultra-High Vacuum (Uhv) Conditions Using Tpd And Sfg Spectroscopy, Quy Loi, Kevin Alvorado Jimenez, Sarah Lelea, Lauren Villegas, Jerry Larue

Student Scholar Symposium Abstracts and Posters

Catalysts are important in manufacturing processes, as they make them more efficient and useful. To develop better catalysts, we need to know how they work by studying how methanol breaks down on platinum. TPD and TD-SFG spectroscopy are used to study by providing the vibrational spectra of methanol on the platinum surface as temperature changes.

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Functionalized Nanoprobes For Multiplexed Surface Enhanced Raman Spectroscopic Detection Of Cancer Biomarkers, Sydney D. Hakimi May 2023

Functionalized Nanoprobes For Multiplexed Surface Enhanced Raman Spectroscopic Detection Of Cancer Biomarkers, Sydney D. Hakimi

Undergraduate Honors Theses

Cancer has a huge impact on people across the world. In 2020, there were about 19.3 million cancer cases and approximately 10 million deaths globally. Early detection and diagnosis of cancer results in a higher rate of survival of the disease. A key challenge is the need for a highly sensitive technique for early cancer detection. Surface-enhanced Raman spectroscopy and scattering (SERS) is a technique that can address the challenge by detecting biomarkers such as Carcinoembryonic antigen (CEA) and Neuron-specific enolase (NSE), which provide diagnostic information for assessing cancer detection. This work focuses on the use of gold nanoprobes conjugated …

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Hollow Mn3o4 Nanoparticles For Catalytic Oxidation Of Alkenes In Air, Nathan R. Loutsch May 2023

Hollow Mn3o4 Nanoparticles For Catalytic Oxidation Of Alkenes In Air, Nathan R. Loutsch

Honors Thesis

Oxidized hydrocarbons (epoxides, alcohols, carboxylic acids, ketones, and aldehydes) have many uses including fuel production, pollution treatment, and chemical synthesis. These compounds can be formed by oxidizing alkenes and alkanes with the assistance of a catalyst. Heterogeneous catalysts have greater recyclability, but traditionally have lower activity and selectivity. Due to the increased relative surface area, nanomaterials can overcome some of the physical limitations. The Hoefelmeyer lab developed a new nanomaterial: hollow Mn3O4 nanoparticles. Sensitive synthetic conditions have been optimized. Due to the increased relative number of edge and corner atoms, the reactive properties of most small nanomaterials increase. Because of …

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Utilization Of Cellulose Symbiotic Culture Of Bacteria And Yeast (Scoby) With Sweet Tea Media As Methylene Blue And Brilliant Green Biosorbent Material, Leonard Mateus Sigiro, Ahmad Maksum, Donanta Dhaneswara May 2023

Utilization Of Cellulose Symbiotic Culture Of Bacteria And Yeast (Scoby) With Sweet Tea Media As Methylene Blue And Brilliant Green Biosorbent Material, Leonard Mateus Sigiro, Ahmad Maksum, Donanta Dhaneswara

Journal of Materials Exploration and Findings

The cellulose from Symbiotic Culture of Bacteria and Yeast (SCOBY) can be used as a biosorbent for dye adsorption, such as Methylene Blue and Brilliant Green. This study used sweet tea with a 6% of sugar concentration and 14 days of fermentation time to synthesize biosorbent material from SCOBY. The results from this synthesis are then characterized using FTIR, SEM, and BET. From the result of characterization, it was found that SCOBY has pores formed from cellulose. The results of the average pore size are 1.5976nm with a pore volume of 0.229cc/g, while the specific surface area is 143.244m2/g. The …

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Enhancing Compatibility And Mechanical Properties Of Natural Rubber Composites, Krisma Yessi Sianturi, Adam Febriyanto Nugraha, Belle Kristaura, Mochamad Chalid May 2023

Enhancing Compatibility And Mechanical Properties Of Natural Rubber Composites, Krisma Yessi Sianturi, Adam Febriyanto Nugraha, Belle Kristaura, Mochamad Chalid

Journal of Materials Exploration and Findings

Pure natural rubber (NR) exhibits low mechanical properties, necessitating the incorporation of additives like vulcanizing agents and fillers. Carbon black and silica, conventional fillers, are relatively expensive and not environmentally friendly. This study explores using Oil Palm Empty Fruit Bunch (OPEFB) fiber as an affordable, abundant, and biodegradable alternative filler for NR. However, compatibility issues arise between the nonpolar NR and the polar OPEFB fiber. A latex-starch hybrid coupling agent (CA (NR-St)) was added to the composite formulation to address this. NR, OPEFB fiber, and the coupling agent were mixed using an open roll mill with a 10 phr OPEFB …

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Crystal Chemistry, Optic And Magnetic Characterizations Of A New Copper Based Material Templated By Hexahydrodiazepine, Mansoura Bourwina, Rawia Msalmi, Sandra Walha, Mark M. Turnbull, Thierry Roisnel, Ahlem Guesmi, Ammar Houas, Naoufel Ben Hamadi, Houcine Naïli May 2023

Crystal Chemistry, Optic And Magnetic Characterizations Of A New Copper Based Material Templated By Hexahydrodiazepine, Mansoura Bourwina, Rawia Msalmi, Sandra Walha, Mark M. Turnbull, Thierry Roisnel, Ahlem Guesmi, Ammar Houas, Naoufel Ben Hamadi, Houcine Naïli

Chemistry

Crystals of the new organic-inorganic material (DAP-H2)[CuBr4] (1); (DAP = hexahydrodiazepine (C5H14N2)) were successfully synthesized by slow evaporation and characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermal analysis, UV-Vis-NIR diffuse reflectance spectroscopy, and magnetic measurements. X-ray investigation demonstrates that 1 crystallizes in the monoclinic space group C2/c. The supramolecular crystal structure of 1 is guided by several types of hydrogen bonding which connect anions and cations together into a three-dimensional network. The optical band gap was determined by diffuse reflectance spectroscopy to be 1.78 eV for a direct allowed transition, implying that …

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Excitation Power Dependence Of Blinking In Copper-Indium-Sulfide Quantum Dots, Nicholas Chambers May 2023

Excitation Power Dependence Of Blinking In Copper-Indium-Sulfide Quantum Dots, Nicholas Chambers

Physics Undergraduate Honors Theses

Under continuous excitation, quantum dots exhibit random transitions between fluorescent ON states and non-fluorescent OFF states --- a phenomenon known as blinking. A physical description of the mechanism responsible for blinking that applies broadly to many types of quantum dots remains under debate. We study the blinking behavior of the non-toxic CuInS2 quantum dot, a system that has seen little investigation at the single-particle level. In particular, the optical properties of CuInS2 quantum are often improved by adding ZnS to the nanoparticles, but this addition leads to complex structural-optical property relationships that are even less understood. To probe the relationship …

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Fragment Based Drug Development Based On 6,7-Dimethoxyquinazoline As A Core Scaffold, Cody M. Orahoske May 2023

Fragment Based Drug Development Based On 6,7-Dimethoxyquinazoline As A Core Scaffold, Cody M. Orahoske

ETD Archive

The work entitled “Fragment Based Drug Design based on 6,7- Dimethoxyquinazoline core structure” presents a unique approach to drug discovery, specifically focusing on the pharmacophore 6,7-dimethoxyquinazoline. This study explores the structural diversity of 6,7-Dimethoxyquinazoline derivatives to identify other pharmacologically relevant targets, with evidence indicating that this core structure possesses intrinsic properties that make it suitable as a base structure of small molecule drugs. Furthermore, this pharmacophore has been observed in various approved therapeutics or drug candidates under investigation, highlighting its importance in drug discovery. My research showcases of 6,7-dimethoxyquinazoline core structure been derivatized to generate an anti-trypanosomiasis drug candidates and …

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Characterizing Metabolic Activity Of Fish Liver Microsomes Towards Fluoxetine In Four Fish Species Using Michaelis-Menten Enzyme Kinetics, Morgan Steiner May 2023

Characterizing Metabolic Activity Of Fish Liver Microsomes Towards Fluoxetine In Four Fish Species Using Michaelis-Menten Enzyme Kinetics, Morgan Steiner

Honors College Theses

Discharge of pharmaceuticals into the environment is of emergent concern due to the unknown long-term effects on aquatic organisms. Wastewater treatment plants are not effective in completely removing pharmaceuticals, allowing them to be discharged into aquatic systems. To investigate the potential effects of fluoxetine, a common antidepressant, on aquatic species, the potential of four freshwater fish species to metabolize this drug was investigated. Livers from redbreast sunfish, bluegill, striped jumprock and bluehead chub were collected, homogenized, and centrifuged to collect the microsomes. These microsomes were used in an assay to determine the in vitro hepatic metabolism of fluoxetine by cytochrome …

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Mechanisms Of Formation Of Novel Guanine-Guanine Cross-Links As Major End Products During One-Electron Oxidation Of Guanine Derivatives, Evan Dunn May 2023

Mechanisms Of Formation Of Novel Guanine-Guanine Cross-Links As Major End Products During One-Electron Oxidation Of Guanine Derivatives, Evan Dunn

Undergraduate Honors Theses

Guanine (G), as the most oxidizable base in DNA, is the major focus of studies of oxidation damage to DNA. The present thesis reports the first detailed characterization of G dimerization products potentially resulting from recombination of neutral G• radicals. Previous research has discovered a novel type of products of G• dimerization, D1 and D2, formed from one-electron oxidation of G derivatives. However, the mechanism of this dimerization remains elusive. While there appears to be a tautomeric equilibrium between two forms of G•, G(N1-H)• or G(N2-H)•, it remains unclear which intermediate participates in the formation of …

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Microwave Synthesis Of Carbon Dot Nanoparticles, Hayden Ferguson May 2023

Microwave Synthesis Of Carbon Dot Nanoparticles, Hayden Ferguson

Undergraduate Honors Theses

This study aimed to improve the known microwave method to produce carbon dot nanoparticles from ethylenediamine and citric acid. Carbon dots have recently gained much attention as they have diverse applications, such as bioimaging and drug delivery reagents as cancer theranostics. Research was focused on establishing the ideal time for the synthetic reaction to produce carbon dot nanoparticles with the microwave method. After several trials, the 16-minute trial provided the best results based on Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, fluorescence spectroscopy, and ultraviolet exposure.

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Combining Chiral Chromatographic Stationary Phases And N-Derivatization Strategies For The Qualitative And Quantitative Analysis Of D-Amino Acids, D-Amino Acid Containing Peptides And D-Amino Acid Related Secondary Metabolites Using Liquid Chromatography, Sam Sung May 2023

Combining Chiral Chromatographic Stationary Phases And N-Derivatization Strategies For The Qualitative And Quantitative Analysis Of D-Amino Acids, D-Amino Acid Containing Peptides And D-Amino Acid Related Secondary Metabolites Using Liquid Chromatography, Sam Sung

Chemistry & Biochemistry Dissertations - Archive

Amino acids are essential building blocks in all life on Earth. It was first mistakenly believed that only L-amino acids were of biological relevance in higher organisms, and D-amino acids were laboratory artifacts or biologically irrelevant. It is well accepted today that various D-amino acids exist in different organisms, including humans, and some even play critical roles in biological pathways and processes. In addition, aberrant levels of certain D-amino acids have been reported in patients with varying diseases. It has been proposed that the aberrant variations in the levels of D-amino acids in biological fluids may serve as biomarkers for …

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Analysis Of Isotopic Isomers By Gas Chromatography And Molecular Rotational Resonance Spectroscopy And Enantioselective Method Development By Liquid Chromatography, Saba Aslani May 2023

Analysis Of Isotopic Isomers By Gas Chromatography And Molecular Rotational Resonance Spectroscopy And Enantioselective Method Development By Liquid Chromatography, Saba Aslani

Chemistry & Biochemistry Dissertations - Archive

This dissertation focuses on developing improved methods and a better understanding of gas and liquid chromatographic separation of isotopic isomers and enantiomers. The second and third chapters of this thesis discuss analytical determination of isotopic isomers using gas chromatography. Deuterated compounds have found applications in many fields. They are used in drug discovery due to increased stability and bioavailability and reduced toxicity of the deuterated drug molecules. Also, deuterated compounds are used to investigate reaction mechanisms and rate determining steps. One of the methods of synthesizing deuterated compounds is starting from lower molecular weight deuterated building blocks. Therefore, analysis and …

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Epimeric Peptides In Alzheimer’S Disease: Implications For Liquid Chromatography-Mass Spectrometry And Immunotherapies, Elizabeth Readel May 2023

Epimeric Peptides In Alzheimer’S Disease: Implications For Liquid Chromatography-Mass Spectrometry And Immunotherapies, Elizabeth Readel

Chemistry & Biochemistry Dissertations - Archive

Evidence has shown that the extracellular deposition of amyloid-beta (Aβ) peptide is a contributing factor of Alzheimer’s disease. Further, modifications to Aβ peptides may enhance the deposition of Aβ plaques and/or contribute to the neurodegeneration in AD patients. These aberrations include the isomerization and epimerization of L-Asp and D-Ser residues to form D-Asp, L/D-iso-Asp, and D-Ser residues, respectively. Therefore, considerable effort has been expended to create effective methods to distinguish such aberrant Aβ peptides from wild type. A useful technique to extract aberrant Aβ peptides in AD patients is by immunotherapies, or antibodies. A few immunotherapies are thought to provide …

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Peripheral Blood Mononuclear Cell Mitochondrial Dysfunction In Acute Alcohol-Associated Hepatitis, Annette Bellar, Nicole Welch, Jaividhya Dasarathy, Amy Attaway, Ryan Musich, Avinash Kumar, Jinendiran Sekar, Saurabh Mishra, Yana I. Sandlers, Et. Al May 2023

Peripheral Blood Mononuclear Cell Mitochondrial Dysfunction In Acute Alcohol-Associated Hepatitis, Annette Bellar, Nicole Welch, Jaividhya Dasarathy, Amy Attaway, Ryan Musich, Avinash Kumar, Jinendiran Sekar, Saurabh Mishra, Yana I. Sandlers, Et. Al

Chemistry Faculty Publications

Background: Patients with acute alcohol-associated hepatitis (AH) have immune dysfunction. Mitochondrial function is critical for immune cell responses and regulates senescence. Clinical translational studies using complementary bioinformatics-experimental validation of mitochondrial responses were performed in peripheral blood mononuclear cells (PBMC) from patients with AH, healthy controls (HC), and heavy drinkers without evidence of liver disease (HD).
Methods: Feature extraction for differentially expressed genes (DEG) in mitochondrial components and telomere regulatory pathways from single-cell RNAseq (scRNAseq) and integrated 'pseudobulk' transcriptomics from PBMC from AH and HC (n = 4 each) were performed. After optimising isolation and processing protocols for functional studies in …

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Developing Chemo-Proteomics Methods For Tyrosine Conjugation And Studies Of Organometallic Complexes Of Gold., Adway Ouseph Zacharias May 2023

Developing Chemo-Proteomics Methods For Tyrosine Conjugation And Studies Of Organometallic Complexes Of Gold., Adway Ouseph Zacharias

Chemistry & Biochemistry Dissertations - Archive

The incredible changes in MS instrumentation since the late 1980s with the advent of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) has revolutionized protein chemistry. Mass spectrometry coupled with chemical crosslinking is a powerful tool to decipher protein structure and protein-protein interactions. A majority of commercially available crosslinkers target only few amino acid residues such as lysine, arginine and cysteine, thereby limiting the utility of this technology. The prospect of using chemical reagents to target amino acids is challenging since covalent labeling experiments are performed under physiological aqueous conditions that may be detrimental to the stability of these reagents. …

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Developing Methods For Pattern Transfer In Photoelectrochemical Lithography, Ashlyn Descarpentrie May 2023

Developing Methods For Pattern Transfer In Photoelectrochemical Lithography, Ashlyn Descarpentrie

Chemistry & Biochemistry Undergraduate Honors Theses

The microprocessor industry has historically been driven by the goal of shrinking devices. To create features small enough to fit on such devices, photolithography has conventionally been used in the micropatterning of noble metal surfaces. Photolithography is a complicated and expensive process that involves a cleanroom, metallization processes, and photoresist. While this investment makes sense for high revenue applications, a number of microelectronic devices do not require nanometer-scale patterned features. Examples of such applications include specific types of antennae, sensing electrodes, and photocatalysts. Photolithography for these devices is thus too costly in both money and energy. The Coridan lab has …

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Low-Cost Microstereolithography 3d Printing With Microfluidic Microsampling Applications, Lauren Twombly May 2023

Low-Cost Microstereolithography 3d Printing With Microfluidic Microsampling Applications, Lauren Twombly

Chemistry & Biochemistry Undergraduate Honors Theses

The growing field of stereolithography 3D printing has welcomed a new age ofmicrofluidic device fabrication techniques. When compared to previous planar fabrication techniques such as soft-lithography, stereolithography 3D printing offers highly automated procedures, reduced fabrication times, and greater complexity of device features. To date, the greatest tradeoff for 3D printing in microfluidic device fabrication is poorer resolution when compared to soft-lithography which can produce feature sizes on the nanometer scale. The poorer resolution of 3D printing limits the feasible size of features. While highly sophisticated 3D printers are capable of achieving sub 10 μm resolution, these instruments are incredibly expensive …

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An Investigation Of Peak Shape Models In Chiral Separations, Ryan Jacob Burk May 2023

An Investigation Of Peak Shape Models In Chiral Separations, Ryan Jacob Burk

Chemistry & Biochemistry Theses - Archive

The use of superficially porous particles in chromatography has led to significant improvements in separation efficiency. However, peak asymmetry in enantiomeric separations causes performance comparisons across particle types a challenge. In this study, we screened 28 pharmaceutically relevant compounds and developed practical methods to reduce peak asymmetry in normal phase chiral chromatography. The use of additives was found to be effective in reducing peak tailing for all compounds, including neutrals. Additionally, we observed that solvent mismatch with the eluent can cause system peak interference, which can be managed by reducing injection volumes. To more accurately assess the performance of the …

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Detection Of Nitrogen Dioxide Via Graphene-Enhanced Raman Scattering, Spencer Hazeslip May 2023

Detection Of Nitrogen Dioxide Via Graphene-Enhanced Raman Scattering, Spencer Hazeslip

Chemistry & Biochemistry Undergraduate Honors Theses

This paper presents the development of a nitrogen dioxide (NO2) sensor that utilizes the phenomenon of graphene-enhanced Raman scattering (GERS). The sensor consists of monolayer graphene on a silicon wafer, functionalized noncovalently with Copper(II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (CuTTPc) via the solution soaking method. A custom sensing chamber was constructed to enable Raman spectra to be collected during NO2 exposure. The response of the sensor was found to be linear between 10 and 100 ppm NO2, indicating that it could be used for both detection and quantification. Furthermore, the sensor was shown to be reusable after …

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Carbon Dioxide Reduction On Large Area Liquid Metal Gallium-Indium Electrocatalysts, Thomas Hollis May 2023

Carbon Dioxide Reduction On Large Area Liquid Metal Gallium-Indium Electrocatalysts, Thomas Hollis

Chemistry & Biochemistry Undergraduate Honors Theses

Carbon dioxide (CO2) is widely known as a greenhouse gas that contributes to global warming due to the burning of fossil fuels. The carbon dioxide reduction reaction (CO2RR) is widely studied to reutilize CO2 to useful products, including methane, ethane, and carbon monoxide. This project studies the use of liquid metal gallium-indium as an electrocatalyst to perform CO2 reduction to carbon monoxide (CO) or possibly solid carbon in various solutions. Gallium-indium is characterized and studied through its “wetting” properties and adhesion to substrate foil through the measurement of contact angles inside solution. These liquid …

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Dual Crosslinked Poly(Acrylamide-Co-N-Vinylpyrrolidone) Microspheres With Re-Crosslinking Ability For Fossil Energy Recovery, Jingyang Pu, Baojun Bai, Jiaming Geng, Na Zhang, Thomas Schuman May 2023

Dual Crosslinked Poly(Acrylamide-Co-N-Vinylpyrrolidone) Microspheres With Re-Crosslinking Ability For Fossil Energy Recovery, Jingyang Pu, Baojun Bai, Jiaming Geng, Na Zhang, Thomas Schuman

Chemical and Biochemical Engineering Faculty Research & Creative Works

Microspheres have been proposed to be applied in controlling wastewater production for mature oilfields and migrating leakage for gas and nuclear waste storage. However, it remains challenging for stacked microspheres to maintain strong blocking ability in micron-sized small pores or fractures. in this study, a novel microsphere was developed with comprehensive properties including high deformability and long re-crosslinking time upon tunable swelling ratio for the applications. a dual covalent and physical crosslinking strategy was used to develop novel microspheres reinforced by a hydrogen bond (H-bond, between pyrrole ring and amide group) and coordination bond (between chromium acetate (CrAc) and carboxyl …

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Nb3Sn Coating Of Twin Axis Cavity And Other Complex Srf Cavity Structures, Jayendrika Kumari Tiskumara May 2023

Nb3Sn Coating Of Twin Axis Cavity And Other Complex Srf Cavity Structures, Jayendrika Kumari Tiskumara

Physics Theses & Dissertations

In the field of Accelerator Science, for the low cost and increased quality factor, thin films coated niobium cavities are used in the modern SRF research. Within the potential substances, Nb3Sn has shown higher critical temperature than niobium. Here the tin vapor diffusion method is used as the preferred technique to coat niobium cavities. So far, only elliptical cavities have been coated with Nb3Sn and this technique has not yet been applied to cavities with complex geometries, which are also helpful in the accelerator science field. The Half-wave resonator could provide us data across frequencies of …

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