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Articles 1 - 30 of 117
Full-Text Articles in Physical Sciences and Mathematics
Electrodeposition Studies Of Gold Nanoparticles And Alginate Hydrogel Films., Harikrishnan Nambiathan Nambiar
Electrodeposition Studies Of Gold Nanoparticles And Alginate Hydrogel Films., Harikrishnan Nambiathan Nambiar
Electronic Theses and Dissertations
This dissertation investigates the electrochemical deposition (ECD) and electrophoretic deposition (EPD) processes involving citrate (cit)-stabilized Au nanoparticles (NPs) and calcium alginate (Ca-Alg-Au NP) hydrogel films. The first part of the dissertation investigates the influence of NP size, surface area (SA) coverage, and ligand stabilizers on the electrochemical growth of Au on Au NPs, aiming to enhance our understanding of the growth process during the nucleation and growth of metal NPs. The growth kinetics depend on Au NP size (4 nm > 15 nm > 50 nm) for a constant SA coverage, as determined by the overpotentials for ECD. The growth rate increases …
Structural, Magnetic, Electrical, Pseudocapacitive, And Electrocatalytic Properties Of Bilayered Ruddlesden-Popper Oxides., Chandana Kananke-Gamage
Structural, Magnetic, Electrical, Pseudocapacitive, And Electrocatalytic Properties Of Bilayered Ruddlesden-Popper Oxides., Chandana Kananke-Gamage
Electronic Theses and Dissertations
Ruddlesden Popper (RP) oxides are perovskite-derived functional materials with the general formula An-1Aʹ2BnO3n+1, where A/Aʹ is often a lanthanide or alkaline earth metal, and B is usually a transition metal. These materials contain perovskite-like connectivity, where BO6 units share apexes to form layers that are stacked above each other. The number of layers in each stack is represented by n in the above formula. The spaces between stacks are often occupied by lanthanide or alkaline-earth metals (Aʹ-site metals), which also reside in intra-stack spaces (A-site) between the octahedra. Oxide materials derived from perovskites have been studied for a wide range …
Comprehensive Analysis And Forensic Investigation Of Cyanide, Thiocyanate, And 2-Amino-2-Thiazoline-4-Carboxylic Acid In-Ante- And Postmortem Blood Utilizing Advanced Analytical Techniques, Abdullah Hamad Alluhayb
Comprehensive Analysis And Forensic Investigation Of Cyanide, Thiocyanate, And 2-Amino-2-Thiazoline-4-Carboxylic Acid In-Ante- And Postmortem Blood Utilizing Advanced Analytical Techniques, Abdullah Hamad Alluhayb
Electronic Theses and Dissertations
Cyanide (CN), present as cyanide anion (CN-) or hydrogen cyanide (HCN), is a deadly poison. The main mechanism of CN toxicity is blocking terminal electron transfer, leading to cellular hypoxia, cytotoxic anoxia, and potential death. Determining blood CN concen-trations along with its major metabolite, thiocyanate (SCN-), is crucial. A sensitive method for concurrent detection of CN and SCN- from human ante- and post-mortem blood via liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis was devel-oped. The method involved active microdiffusion with chemical modification using naph-thalene-2,3-dicarboxaldehyde (NDA) and taurine, while monobromobimane (MBB) mod-ification was used for SCN-. The method showed good sensitivity for …
Speciated Isotope Dilution Mass Spectrometry In Combination With Thor’S Hammer Metaspike Technology For The Assessment Of Low-Level Biomarkers For Human Health Evaluation, Ashley Ebert
Electronic Theses and Dissertations
Our research team has been focused on quantifying important biological analytes in human blood samples to delineate the biochemical processes underlying certain states of dysfunction and evaluate treatment efficacy. These efforts have been guided by laboratory measurements with the input of medical experts. Speciated isotope dilution mass spectrometry (SIDMS) explained in detail in EPA Method 6800 has been successfully applied in the quantification of an important biomarker analyte for immune function and detoxification processes: glutathione. Past research has proven the molecule a biomarker for autism spectrum disorder (ASD) in the form of the reduced/oxidized glutathione (GSH/GSSG) ratio, and literature has …
Nitrogen-Doped And Phosphorus-Doped Epoxy-Sealed Carbon Fiber Ultramicroelectrodes As Electrochemical Sensors For Detection Of Hydrogen Peroxide, Emmanuel Peprah-Yamoah
Nitrogen-Doped And Phosphorus-Doped Epoxy-Sealed Carbon Fiber Ultramicroelectrodes As Electrochemical Sensors For Detection Of Hydrogen Peroxide, Emmanuel Peprah-Yamoah
Electronic Theses and Dissertations
Ultramicroelectrodes (UMEs) are useful as probes for evaluating electroactive species in confined spaces (e.g., inside living cells) and for measuring fast electrochemical reactions. However, UME applications often require modification of the electrode surface to improve selectivity and sensitivity towards target analytes. Previous research in our group demonstrated that a simple soft nitriding method introduces surface nitrogen (N)-containing groups on carbon fiber (CF), leading to improved electroreduction of hydrogen peroxide (H2O2) on CF-UMEs. However, sensitivity for H2O2 detection using N-CF-UMEs was low compared to that for other modified UMEs. As an alternative to N-CF-UMEs, …
Alpha, Beta-Unsaturated Aldehydes: The Underrepresented Markers Of Disease., Saurin Sutaria
Alpha, Beta-Unsaturated Aldehydes: The Underrepresented Markers Of Disease., Saurin Sutaria
Electronic Theses and Dissertations
The peroxidation of unsaturated fatty acids is a widely recognized metabolic process that creates a complex mixture of volatile organic compounds including aldehydes. Elevated levels of reactive oxygen species in cancer cells promote random lipid peroxidation, which leads to an increase in a variety of aldehydes. Many of these volatile aldehydes are exhaled and are of interest as potential markers of disease. Chapter 1 presents a review of reported aldehydes in the exhaled breath of lung cancer patients. alpha,beta-Unsaturated aldehydes, detected primarily when derivatized during exhaled breath preconcentration, are underreported in the reviewed articles. Chapter 1 concludes with our hypothesis …
Intersections Of Environmentalism, Chemistry, And Racism: An Experimental Study Of Halobenzene Hydrogenolysis And Critical Communication Studies Of Equitable Learning Practices Rooted In Black Feminism, Lauren O. Babb
Electronic Theses and Dissertations
Increasing concentrations of fluorinated aromatic compounds in surface water, groundwater, and soil pose threats to the environment. Fundamental studies that elucidate mechanisms of dehalogenation for C-X compounds (where X represents a halide) are required to develop effective remediation strategies. For halogenated benzenes, previously published research has suggested that the strength of the C-X bond is not rate-determining in the overall rate of dehalogenation. Instead, the rate-determining step has been hypothesized to be adsorption of the C-X compound onto the surface of a catalyst. Building on this hypothesis, in this work, we examine the reaction kinetics of fluorobenzene conversion to benzene, …
Biomaterials: From Scaffold Design To Implant Optimization, Jennifer Marie Armen
Biomaterials: From Scaffold Design To Implant Optimization, Jennifer Marie Armen
Electronic Theses and Dissertations
This work encompasses three individual projects concerning biomaterials and their modifications. Chemically-Induced Cross-Linking of Peptidic Fibrils for Scaffolding Polymeric Particles and Macrophages EAK16-II (EAK) is a self-assembling peptide (SAP) that forms β-sheets and βfibrils through ionic-complementary interactions at physiological ionic strengths. The soft materials can be injected in vivo, creating depots of drugs and cells for rendering pharmacological and biological actions. The scope of the applications of EAK is sought to extend to tissues through which the flow of extracellular fluid tends to be limited. In such anatomical locales the rate and extent of the fibrilization are limited insofar as …
Spectroscopic Measurements Of Meibum Compositional, Structural, And Functional Relationships To Elucidate The Role Of Meibum In Dry Eye., Anthony Chigozie Ewurum
Spectroscopic Measurements Of Meibum Compositional, Structural, And Functional Relationships To Elucidate The Role Of Meibum In Dry Eye., Anthony Chigozie Ewurum
Electronic Theses and Dissertations
The major aim of my dissertation was to investigate the etiology of dry eye disease which affects about 7 million people in the United States, causing symptoms that can lead to visual disturbance. Correlation between dry eye and an abnormal lipid layer of the tear film has been found. Tear film lipids originate mostly from the meibomian glands. Cholesteryl ester (CE) and Wax ester (WE) lipids make up most of the human meibum lipidome and the CE/WE ratio has been shown to decrease in patients with meibomian gland dysfunction. Model studies using synthetic CE and WE, although providing some insight, …
Development Of A Chromatographic Method To Authenticate Aspirin Brands, Megan Guetzloff
Development Of A Chromatographic Method To Authenticate Aspirin Brands, Megan Guetzloff
Electronic Theses and Dissertations
Counterfeit pharmaceuticals pose a threat to society that can include inaccurate amounts of the active pharmaceutical ingredient (API), no API, or containing off-target compounds. For example, there are many recent examples of counterfeit pharmaceuticals containing potentially lethal doses (> 2 mg) of fentanyl (i.e., a synthetic opioid). Current measures to combat illicit pharmaceuticals (e.g., unique packaging and product serialization) have merit, however with evolved technologies, counterfeiters can relatively easily simulate these measures and continue to distribute illicit pharmaceuticals. The only accurate way to definitively determine that a suspected counterfeit is, in fact, counterfeit is advanced chemical analysis. However, current methods …
Synthesis Of Functionalized Aromatic Heterocyclic Compounds And Its Applications In Organized Self-Assemblies, Emmanuel T. Fasusi
Synthesis Of Functionalized Aromatic Heterocyclic Compounds And Its Applications In Organized Self-Assemblies, Emmanuel T. Fasusi
Electronic Theses and Dissertations
1,2,3-triazoles due to their structure, possess good optical properties and are capable of molecular recognition by their supramolecular capabilities of utilizing weak forces of interaction (such as hydrogen bonding, dipole interaction) in establishing a close association with targets. They are easy to synthesize, which opened the opportunity for a wide pharmaceutical application, mostly as pharmacological scaffolds. However, challenges such as poor water solubility, inefficient drug delivery and increased toxicities due to frequent dosing of drugs are commonly faced which reduces the efficacy of the drugs. It is therefore important to have “delivery vehicles” which could help transport the drugs to …
Facile Nitrogen-Doping Of Screen-Printed Carbon Electrodes For Detection Of Hydrogen Peroxide, Emmanuel Nkyaagye
Facile Nitrogen-Doping Of Screen-Printed Carbon Electrodes For Detection Of Hydrogen Peroxide, Emmanuel Nkyaagye
Electronic Theses and Dissertations
Screen-printed carbon electrodes (SPCEs) have garnered much attention as sensors due to their simplicity and relatively low cost. However, to impart necessary selectivity and sensitivity for specific applications, modification of the SPCE surface, which can involve time-consuming procedures or costly equipment/materials, is typically required. Here, a simple nitrogen-doping process based on NH4OH was used to modify SPCEs prepared from commercially available ink for electrochemical detection of H2O2, a common target for biosensing strategies and indicator of cell stress. XPS studies showed that NH4OH treatment of SPCEs led to a nearly 5-fold increase …
Gradient Generating Microfluidic Coculture System For Disease Modeling And Neural Development, Phaneendra Chennampally
Gradient Generating Microfluidic Coculture System For Disease Modeling And Neural Development, Phaneendra Chennampally
Electronic Theses and Dissertations
Cellular microenvironment or cell niche plays an important role in developmental biology and disease pathophysiology. Physical or chemical signals in microenvironment drive the cellular activity. These signaling molecules are generated from the surrounding cells/tissues as part of intercellular communication; a fundamental property of a cell. Dynamic profile of these signaling molecules in the microenvironment plays a pivotal role in transfer of molecular information from cell to cell in disease proliferation or fate determination. Recapitulating these signaling cues in an in vitro study is difficult to achieve using standard cell culture techniques. However microfluidic systems are capable of addressing these issues, …
The Development And Optimization Of A Two-Dimensional Lc-Qqq-Ms-Method For The Combined Analysis Of Synthetic Cannabinoids And Designer Cathinones In Urine, Holly Penefsky
Electronic Theses and Dissertations
The compounds and chemical compositions of synthetic cannabinoids and designer cathinones are designed to mimic the intoxicating effects of D9-tetrahydrocannabinol and amphetamines, respectively. In order to skirt existing drug laws, non-controlled ingredients are used, and the original chemical structures of current drugs are being modified using analogs or derivatives. These continually changing chemical compositions pose a problem for policymakers, and forensic and analytical scientists, as users are able to attain a “legal high” and avoid detection in standard drug screens. Commonly, toxicology laboratories utilize a screening method, such as immunoassay, for the presumptive identification of designer drugs. When …
Mass Spectrometry Based Metabolomics And Lipidomics., Fang Yuan
Mass Spectrometry Based Metabolomics And Lipidomics., Fang Yuan
Electronic Theses and Dissertations
Metabolomics and lipidomics studies are important to understand living organisms at the molecular level. In this dissertation, I conducted various untargeted and targeted metabolomics and lipidomics studies using mass spectrometry based analytical platforms. Firstly, I investigated the androgen depletion effects on fecal metabolites in a mouse model of systemic lupus erythematosus and metabolite biomarkers for colorectal cancer using two-dimensional gas and liquid chromatography-mass spectrometry. Secondly, I investigated the relationship between gut microbiota-mediated resistance and susceptibility to malaria and the production of short-chain fatty acids using gas chromatography-mass spectrometry. Thirdly, I developed a high-throughput liquid chromatography-mass spectrometry method to profile long-chain …
Nitrogen-Doped Carbon Fiber Ultramicroelectrodes As Electrochemical Sensors For Detection Of Hydrogen Peroxide, Eric Wornyo
Nitrogen-Doped Carbon Fiber Ultramicroelectrodes As Electrochemical Sensors For Detection Of Hydrogen Peroxide, Eric Wornyo
Electronic Theses and Dissertations
Carbon fiber ultramicroelectrodes (CF-UMEs) are commonly used as electrochemical probes and sensors due to their small size, fast response, and high signal-to-noise ratio. Surface modification strategies are often employed on CF-UMEs to improve their selectivity and sensitivity for desired applications. However, many modification methods are cumbersome and require expensive equipment. In this study, a simple approach known as soft nitriding is used to prepare nitrogen-doped CF-UMEs (N-CF-UMEs). Nitrogen groups introduced via soft nitriding act as electrocatalytic sites for the breakage of O-O bonds during the reduction of peroxides like H2O2, a common target of biosensing strategies. …
An Electrochemical Immunoassay System For Measuring Circulating Protein Biomarkers Of Pediatric Soft Tissue Sarcoma, Ivy Antwi
Electronic Theses and Dissertations
Measurement of circulating protein biomarkers associated with disease can facilitate early detection, help guide treatment strategies and improve patient outcomes beyond current standards of care. The combination of inexpensive 3D-printed flow cells and electrochemical biosensors has recently emerged as a viable platform for low-cost, reliable biomarker measurements. Here, we report an electrochemical immunoassay system based on simple graphite electrode arrays, 3D-printed flow cells, and signal-generating magnetic bead bioconjugates for simultaneous detection of three biomarker proteins (cancer antigen 125 (CA-125), midkine (MK) and osteopontin (OPN)) associated with pediatric soft tissue sarcomas (PSTS). Magnetic bead bioconjugates are functionalized with large amounts of …
Theranostic Nanoparticles Folic Acid-Carbon Dots-Drug(S) For Cancer, Godwin Kweku Babanyinah
Theranostic Nanoparticles Folic Acid-Carbon Dots-Drug(S) For Cancer, Godwin Kweku Babanyinah
Electronic Theses and Dissertations
This study aims to prepare theranostic nanoparticles (NPs) that are expected to increase cancer diagnostics and therapeutic efficacy. We prepared the NPs constituting carbon dots (CDs) as an imaging agent, folic acid as a targeting agent, doxorubicin (DOX), or gemcitabine (GEM) as chemotherapy agents. The NPs include noncovalent FA-CDs-DOX, covalent CDs-FA-DOX, and covalent FA-CDs-GEM. Through ultraviolet-visible spectroscopy, fluorescence spectroscopy, and Fourier transform-infrared spectroscopy, the fabrication of these NPs was confirmed. It was discovered that the high drug loading efficiency is the noncovalent series while the high drug loading capacity is the covalent series The in-vitro pH-dependent drug release data indicate …
Electrodeposition Of Hydrogen Molybdenum Tungsten Bronze Films And Electrochemical Reduction Of Carbon Dioxide., Mohammad Bajunaid
Electrodeposition Of Hydrogen Molybdenum Tungsten Bronze Films And Electrochemical Reduction Of Carbon Dioxide., Mohammad Bajunaid
Electronic Theses and Dissertations
The foremost aim for performing this study was to focus on the electrodeposition of mixed hydrogen molybdenum tungsten bronze films, which have the potential for e– transfer interactions carrying out the reduction of carbon dioxide. A yellow peroxymolybdic tungstate solution was prepared and used for the electrodeposition of hydrogen molybdenum tungsten bronze films on conductive carbon paper. Electrodeposition was carried out at -2.0 V from 20 - 120 minutes to determine the effect of deposition time on film thickness and CO2 reduction. These films were characterized by X-ray photoelectron spectroscopy. The deposited films served as a working electrode …
Validation Of A Deployable Proteomic Assay For The Serological Screening Of Sexual Assault Samples, Catherine O'Sullivan Brown
Validation Of A Deployable Proteomic Assay For The Serological Screening Of Sexual Assault Samples, Catherine O'Sullivan Brown
Electronic Theses and Dissertations
Protein mass spectrometry (MS) has emerged as a technique to supplant traditional serological tests for body fluid identification. It was hypothesized that proteomic techniques would surpass the sensitivity and specificity of traditional serological techniques. An automated workflow coupled with protein MS has been developed for the confirmatory identification of five biological fluids. A developmental validation was completed, assessing parameters such as reproducibility, sensitivity, ion suppression, and limit of detection. Implementation was determined through tandem sample processing by MS, traditional serological tests, and standard DNA profiling methods. The MS approach offered superior detection limits while also providing true confirmatory results, producing …
Advanced Analytical Techniques For The Analysis Of Therapeutics Of Toxic Inhalation Agents And Pharmacokinetic Investigation, Subrata Bhadra
Advanced Analytical Techniques For The Analysis Of Therapeutics Of Toxic Inhalation Agents And Pharmacokinetic Investigation, Subrata Bhadra
Electronic Theses and Dissertations
Toxic inhalation agents (TIAs), (i.e., cyanide (CN) and reduced sulfur compounds (RSCs)), including hydrogen sulfide (H2S) and methanethiol (MT)) are extremely poisonous upon exposure. Many TIAs act by inhibiting mitochondrial cytochrome c oxidase, resulting in cellular hypoxia, cytotoxic anoxia, apnea, respiratory failure, cardiovascular collapse, seizure and potentially death. CN is generated in structural fires and cigarette smoke as well as in mining, electroplating and polymer processing, whereas H2S and MT are found in petroleum, oil and natural gas, waste treatment facilities and decaying organic matter. All are common occupational gas exposure hazards in chemical industries and for first responders, including …
Novel Acetylcholine Chloride Based Water Immiscible Deep Eutectic Solvent: Formulation, Characterization And Application In Drug Solubilization, Shiksha Subedi
Novel Acetylcholine Chloride Based Water Immiscible Deep Eutectic Solvent: Formulation, Characterization And Application In Drug Solubilization, Shiksha Subedi
Electronic Theses and Dissertations
Deep eutectic solvents (DESs) are the emerging class of new and inexpensive solvents composed of two or three safe components capable of self-association through hydrogen bond interaction. The depression in the melting point characterizes DESs compared to those of the individual components. These solvents have properties like the traditionally used ionic liquids (ILs), but they can offset the significant drawbacks of ILs, such as biodegradability, toxicity, and complex synthesis. Due to these remarkable advantages, the research in DESs is increasing exponentially. However, current deep eutectic solvents still have limitations to apply to the real chemical industries due to hydrophilicity and …
Accurate Quantitation Of Hexavalent Chromium For Reference Standard Certification And Quality Control Testing Using Speciated Isotope Dilution Mass Spectrometry, James E. Henderson
Accurate Quantitation Of Hexavalent Chromium For Reference Standard Certification And Quality Control Testing Using Speciated Isotope Dilution Mass Spectrometry, James E. Henderson
Electronic Theses and Dissertations
The ability to perform accurate, repeatable, and defensible elemental and molecular speciated analysis is immensely significant for measurements that support human health, environmental science, and industry. This is especially true since trivalent chromium [Cr(III)] is necessary for proper nutrition, while hexavalent chromium [Cr(VI)] is extremely toxic, genotoxic, and carcinogenic. The main challenges associated with speciated analysis are related to reactive species that are continuously transformed or converted to other species during sample processing. Accurate determination of Cr(III) and Cr(VI) species require a method that is capable of monitoring and correcting for interconversion, bias, and instrumental error. Traditional quantitative methods, such …
Functionalized Materials From Atom Transfer Radical Processes, Sean Fischer
Functionalized Materials From Atom Transfer Radical Processes, Sean Fischer
Electronic Theses and Dissertations
This work is focused on the synthesis, characterization, and application of functionalized materials prepared from atom transfer radical processes. Atom transfer radical processes encompass both atom transfer radical addition (ATRA) and polymerization (ATRP) reactions, both of which are catalyzed by ppm amounts of copper complexes. The synthetic efforts of ATRA include increasing adduct selectivity through optimization of reaction conditions to generate small molecules in high to moderate yields. ATRA provides retention of the halogen moiety, which is an attractive functional group that can be further modified with other transformations. Specifically, the copper-catalyzed azide-alkyne [3+2] cycloaddition (CuAAC) allows for the realization …
Design, Synthesis And Application Of Janus Gold Nanoprisms For Directed Self-Assembly., Md. Emtias Chowdhury
Design, Synthesis And Application Of Janus Gold Nanoprisms For Directed Self-Assembly., Md. Emtias Chowdhury
Electronic Theses and Dissertations
Colloidal Janus particles that possess more than one type of surface chemistry or functionalities have drawn significant interest due to their enormous potential in bottom-up synthetic strategies for complex superstructures. Moreover, the property of molecular recognition, tunability, and predictability of the DNA-mediated interactions enable a high degree of control over particle assembly to generate highly ordered nanostructures with emergent applications. In this dissertation, we present our works on the synthesis of Janus particles from anisotropic gold nanoprisms, and DNA- mediated assembly of nanoprisms and polymer beads in four major areas: 1) Facet selective asymmetric functionalization of gold nanoprisms for Janus …
Isolation, Structure Elucidation, And Synthesis Of Natural Products From Marine Cyanobacteria, Keren Solomon
Isolation, Structure Elucidation, And Synthesis Of Natural Products From Marine Cyanobacteria, Keren Solomon
Electronic Theses and Dissertations
This thesis describes the isolation, structure elucidation, and synthesis of natural products from marine cyanobacteria. A crude extract from a cyanobacterium collected in Curacao showed selective affinity for the dopamine D5 receptor in a screen against a panel of CNS receptors. Due to the high similarity of the D5 and D1 receptor, to date there are no known ligands that differentiate them. Attempts to purify the compound responsible for this affinity led to the isolation of the known compound caylobolide A. A second extract from a cyanobacterium collected in Panama underwent bioassay-guided fractionation and yielded the novel …
Using Tandem Mass Spectrometry And Irmpd Spectroscopy To Determine The Intrinsic Reactions Of Uranyl-Containing Ions, Irena Tatosian
Using Tandem Mass Spectrometry And Irmpd Spectroscopy To Determine The Intrinsic Reactions Of Uranyl-Containing Ions, Irena Tatosian
Electronic Theses and Dissertations
Developing a comprehensive understanding of the intrinsic reactivity of uranium-containing species remains an important goal, as it may influence future developments in areas ranging from new approaches to nuclear fuel processing to studies of the migration and fate of the element in the environment. At a more fundamental level, such studies contribute to the understanding of the role that 5-f electrons may play in chemical bonding, the so called “f-electron challenge”. Electrospray ionization (ESI) is an effective way to generate gas-phase complexes containing uranium and uranyl ions for subsequent studies of intrinsic structure and reactivity. Studies in the gas-phase are …
N-Terminal Imine Derivatization For Enhanced De Novo Peptide Sequencing: A Study Of The Fragmentation Pattern Generated From Cid Of Peptide-Imines, Khiry L. Patterson
N-Terminal Imine Derivatization For Enhanced De Novo Peptide Sequencing: A Study Of The Fragmentation Pattern Generated From Cid Of Peptide-Imines, Khiry L. Patterson
Electronic Theses and Dissertations
In this work, the fragmentation pattern derived from model peptides derivatized to create N-terminal imines (Schiff bases) were evaluated. Collision-induced dissociation of the protonated peptide-imines ([M+H]+) generally produced complete series of the sequence informative an and bn ions, now undoubtedly characteristic of the peptide ion species. A novel product ion was also observed, denoted the yǂ ion, determined by IRMPD spectroscopy and density functional theory to be generated from the elimination of the N-terminal amino acid residue despite the N-terminal modification. It was concluded the pathway involved a nucleophilic attack by an amide nitrogen and …
Phenolic Phytochemicals And Their Antioxidant Activities In Maine-Grown Asian, American-Hybrid, And European Plums, Hye Weon Hwang
Phenolic Phytochemicals And Their Antioxidant Activities In Maine-Grown Asian, American-Hybrid, And European Plums, Hye Weon Hwang
Electronic Theses and Dissertations
Plum fruits of 16 plum cultivars derived from three species, Asian, American-hybrid, and European plums, and one cultivar of an interspecific hybrid between Asian plum and apricot were investigated to identify and quantify two major groups of phenolic phytochemicals, anthocyanins and hydroxycinnamic acids (HCAs) by HPLC–DAD/MS. The plums were harvested from 2014 to 2017. Some cultivars were analyzed through consecutive years to determine year-to-year differences and to evaluate the maturity impacts on the concentration of anthocyanins and HCAs from the partial-ripe stage and tree-ripe stage. Anthocyanins were present in red−purple colored plums, but their profiles varied among cultivars and species. …
Polysaccharide And Silver Nanoparticles Based Hydrogels, Porous Materials, And Sensors, Muhammad R. Hossen
Polysaccharide And Silver Nanoparticles Based Hydrogels, Porous Materials, And Sensors, Muhammad R. Hossen
Electronic Theses and Dissertations
Cellulose based hydrogels and porous materials are gaining significant attention across a wide range of applications due to the natural abundance, biodegradability and physicochemical tunability of this polysaccharide. Cellulose nanofibrils (CNF) outperform cellulose fibers in terms of physicochemical tunability since CNF possess relatively high surface area. However, superior dispersibility of CNF in aqueous phase makes it challenging for traditional methods to dewater CNF suspensions to fabricate robust hydrogels and porous materials. In this dissertation, a novel scalable capillary based method to dewater CNF suspensions is invented as well as CNF hydrogels and porous materials with a broad range of porosity …