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2015

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Articles 1051 - 1080 of 1428

Full-Text Articles in Chemistry

Preparation, Chemistry, And Characterization Of Hypervalent Organosulfur Fluorides, Paul R. Savoie Jan 2015

Preparation, Chemistry, And Characterization Of Hypervalent Organosulfur Fluorides, Paul R. Savoie

Legacy Theses & Dissertations (2009 - 2024)

Since the discovery of the pentafluorosulfanyl (SF5) group around the 1960s, progress in exploring the chemistry of aliphatic SF5-containing compounds stagnated because of a lack of efficient synthetic methods. More recent developments in the preparations of SF5-containing compounds afforded easier access to these compounds, and sparked great interest in exploring their chemistry. Chapter 1 discusses the development of efficient methods used to prepare SF5-containing aliphatic compounds.


Novel Nmr Based Technologies To Study Macromolecular Structures, Subhabrata Majumder Jan 2015

Novel Nmr Based Technologies To Study Macromolecular Structures, Subhabrata Majumder

Legacy Theses & Dissertations (2009 - 2024)

Nuclear Magnetic Resonance Spectroscopy (NMR) is one of the principle tools in structural biology to probe macromolecular structures and interactions. The atomic resolution afforded by this technique has been widely used to probe protein-protein, and protein-ligand interactions in-vitro. However, the natural milieu of the proteins is the living cell and the cellular cytoplasm is extremely heterogeneous. The NMR studies of folded protein in-cell, till now, have been limited by non-specific interactions of the cytosol. This thesis outlays a general methodology to study protein structure/interactions inside the living cells using NMR. In a closely related objective, it also describes the use …


Structure And Stability Of Amyloid Fibrils Studied By Advanced Vibrational Spectroscopy, Marudachalam Shanmugasundaram Jan 2015

Structure And Stability Of Amyloid Fibrils Studied By Advanced Vibrational Spectroscopy, Marudachalam Shanmugasundaram

Legacy Theses & Dissertations (2009 - 2024)

Protein misfolding often leads to the formation of refractory protein aggregates like amyloid fibrils. These fibrils possess a highly ordered structure and are implicated in over 25 severe diseases including Alzheimer’s, Parkinson’s and prion diseases. This work was focused on understanding the morphology and conformation of amyloid fibrils and their stability after formation. The deconstruction of fibrils as well as other aggregates like inclusion bodies under mild conditions was also investigated using Archaeal chaperones.


Mass Spectrometry-Based Rnomics : Global Surveys Of Ribonucleotide Modifications As Possible Indicators Of Cell Identity, Epigenetic, Metabolic And Pathological State, Rebecca Erin Rose Jan 2015

Mass Spectrometry-Based Rnomics : Global Surveys Of Ribonucleotide Modifications As Possible Indicators Of Cell Identity, Epigenetic, Metabolic And Pathological State, Rebecca Erin Rose

Legacy Theses & Dissertations (2009 - 2024)

Discovery of the regulatory roles of non-protein coding RNAs (ncRNAs), once considered “junk” or “transcriptional noise”, has prompted a reassessment of the significance of the multifaceted activities of RNA in cellular response, which can result in cell transformation and diseased states. This reassessment, however, can only be accomplished if techniques are developed to capture, characterize and quantify the more than 100 covalent post-transcriptional modifications (PTMs) that adorn natural RNAs. Undoubtedly, the creation of high-throughput platforms such as next-generation sequencing and RNA-seq have provided unparalleled accuracy and sensitivity, however, they rely on strand amplification procedures that are blind to the known …


Luminescence Of Lanthanide Ions In Octahedral Coordinations With Comparison To The Centroid Shift And Host Lattice Exciton Energy, Sam J. Camardello Jan 2015

Luminescence Of Lanthanide Ions In Octahedral Coordinations With Comparison To The Centroid Shift And Host Lattice Exciton Energy, Sam J. Camardello

Legacy Theses & Dissertations (2009 - 2024)

In this dissertation, we have studied the luminescence of the lanthanide ions (Ce3+, Eu2+, Eu3+, Tb3+, and Pr3+), specifically in the highly symmetric octahedral coordination. This high symmetry coordination readily permits the optical properties of the luminescent ions to be determined spectroscopically. Relevant optical parameters such as the Stokes Shift (∆S), red shift (D(2+, 3+, A), crystal field splitting (Ɛcfs), and centroid sift (Ɛc), along with the excitation and emission spectra, are presented. Three different crystal structures were studied, namely, M2+Al2B2O7 (M2+ = Ca, Sr, Ba) doped with Eu2+ and Ce3+, KBaLn3+(BO3)2 (M3+ = all lanthanides, Y, Sc) doped with …


Fluorinated Hypervalent Sulfur Compounds In Synthesis, Cortney Von Hahmann Jan 2015

Fluorinated Hypervalent Sulfur Compounds In Synthesis, Cortney Von Hahmann

Legacy Theses & Dissertations (2009 - 2024)

The polar and steric effects of pentafluorosulfanyl (SF5) substitution on selectivity and reactivity were investigated in the ketene imine [2+2] cycloaddition reaction. The kinetic resolution of racemic aldimines rely on the stereocontrol of cyclization by dipolar substituent effects. Functionalized SF5-bearing β-lactams are used in the preparation of conformationally constrained SF5-containing β-amino acids and peptides, in the study of novel antibacterial agents and in the design of new β-lactamase inhibitors.


Initiated Chemical Vapor Deposition (Icvd) Polymer Thin Films : Structure-Property Effects On Thermal Degradation And Adhesion, Vijay Jain Bharamaiah Jeevendrakumar Jan 2015

Initiated Chemical Vapor Deposition (Icvd) Polymer Thin Films : Structure-Property Effects On Thermal Degradation And Adhesion, Vijay Jain Bharamaiah Jeevendrakumar

Legacy Theses & Dissertations (2009 - 2024)

Opportunities and challenges for chemical vapor deposition (CVD) of polymer thin films stems from their applications in electronics, sensors, and adhesives with demands for control over film composition, conformity and stability. Initiated chemical vapor deposition (iCVD) is a subset of the CVD technique that conjoins bulk free-radical polymerization chemistry with gas-phase processing. The novelty of iCVD technique stems from the use of an initiator that can be activated at low energies (150 – 300 °C) to react with surface adsorbed monomer to form a polymer film. This reduces risk for potential unwarranted side-reactions.


An Investigation Of Alkaline Earth And Rare Earth Elements In Human Bone Following Long-Term Parenteral Nutrition, Aubrey L. Galusha Jan 2015

An Investigation Of Alkaline Earth And Rare Earth Elements In Human Bone Following Long-Term Parenteral Nutrition, Aubrey L. Galusha

Legacy Theses & Dissertations (2009 - 2024)

This investigation focused on a unique collection of archived human bones obtained post-mortem from 7 patients, who had received long-term parenteral nutrition (PN) for up to 21 years. Parenterals are administered intravenously as a nutritional supplement, and may be contaminated with metals, which are completely absorbed into the blood compartment. Some metal contaminants may be deposited in the body’s reservoir for inorganic elements – bone.


Distributions And Formations Of Hono In The Troposphere, Dennis Pu Jan 2015

Distributions And Formations Of Hono In The Troposphere, Dennis Pu

Legacy Theses & Dissertations (2009 - 2024)

Nitrous acid (HONO) is an important reactive nitrogen species and a precursor to the hydroxyl radical. It plays important roles in reactive nitrogen recycling and in photo-oxidant formation in the troposphere. However, much is still unknown about its formation mechanisms and distributions in the troposphere. This research is part of NOMADSS (Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources and Sinks) field study contributed by over 10 research groups in the United States to investigate the tropospheric chemistry of reactive nitrogen, mercury, oxidant and aerosols. One of the goals was to study the HONO distribution and formation mechanisms in the troposphere. …


Characterization Of Metallic And Semimetallic Oxide Nanoparticles In Industrial Wastewater And Associated Toxicity, Gary Roth Jan 2015

Characterization Of Metallic And Semimetallic Oxide Nanoparticles In Industrial Wastewater And Associated Toxicity, Gary Roth

Legacy Theses & Dissertations (2009 - 2024)

Engineered nanomaterials (ENMs) play an increasing role in manufacturing and consumer products. Currently, there is no standard approach to studying ENM toxicity, and a growing body of literature suggests that ENMs may have toxicity differing from similar compounds in bulk or dissolved form. I examined ENMs used in the semiconductor manufacturing process called chemical-mechanical planarization (CMP) for their properties, removal in the wastewater treatment system (WWT), in-vitro toxicity, and location post-inhalation in-vivo. It was found that ENMs in CMP slurries have morphology determined by their elemental composition, but assessment of size and concentration can differ substantially between accepted techniques. Particles …


Molecular Dynamics Simulations Of Small Systems To Improve Base Pairing Parameters Of The Amber-99 Force Field, Angelo Christopher Setaro Jan 2015

Molecular Dynamics Simulations Of Small Systems To Improve Base Pairing Parameters Of The Amber-99 Force Field, Angelo Christopher Setaro

Legacy Theses & Dissertations (2009 - 2024)

Simulations of biochemical systems are being increasingly used to further our understanding of those systems. In broad strokes, chemical simulations can be broken into two categories, those that are rooted in a quantum mechanical approach and those that are classically rooted. Molecular dynamics is one such classical method, which propagates motion of a chemical system via repeatedly solving Newton’s Laws of motion. This approach is less computationally intensive than the quantum mechanical methods and allows for the simulation of systems of tens of thousands of atoms, if not more.


Single-Source Precursors For The Low-Temperature Preparation Of Rechargeable Battery Electrode Materials, Zheng Wei Jan 2015

Single-Source Precursors For The Low-Temperature Preparation Of Rechargeable Battery Electrode Materials, Zheng Wei

Legacy Theses & Dissertations (2009 - 2024)

Lithium ion batteries have revolutionized the portable electronics market and are being intensively pursued now for transportation and for stationary storage of renewable energies. As one of the most promising alternatives, sodium ion batteries are also being actively studied owing to the high abundance and low cost of sodium sources. Electrodes play a critical role in defining the overall performance of secondary batteries, while the morphologies of electrode materials greatly determine their properties. Different synthetic methods afford electrode materials with specific morphology. Compared to traditional electrode preparation techniques, the single-source precursor approach can produce materials at significantly lower temperatures, with …


Advanced Raman Spectroscopic Methods For Structural Characterization Of Amyloid Fibrils And Bionanotubes, Valentin Sereda Jan 2015

Advanced Raman Spectroscopic Methods For Structural Characterization Of Amyloid Fibrils And Bionanotubes, Valentin Sereda

Legacy Theses & Dissertations (2009 - 2024)

Amyloid aggregation is a specific form of protein misfolding and self-assembly related to several degenerative pathologies like Alzheimer's and Parkinson's diseases, type-II diabetes, etc. This association with deadly diseases has made amyloid fibrils the focus of intensive research for many decades. Most recently, a significant interest to protein fibrils was also due to the application of the remarkable self-assembling capabilities to form well-structured nano-biomaterials. Self-assembly of short peptide sequences into well-organized structures is another important strategy for bottom-up fabrications of nano-biomaterials. One of the most commonly used building blocks is diphenylalanine, a short dipeptide that has been identified as playing …


Two-Dimensional Chalcogenides : Material Synthesis And Nano-Device Applications, Robin Bay Jacobs-Gedrim Jan 2015

Two-Dimensional Chalcogenides : Material Synthesis And Nano-Device Applications, Robin Bay Jacobs-Gedrim

Legacy Theses & Dissertations (2009 - 2024)

Low-dimensional nanostructures exhibit distinct properties from their bulk counterparts. Here the synthesis of novel low-dimensional nanostructures is demonstrated using both top down and bottom up processes and their properties are investigated. Two-dimensional (2D) binary sesquichalcogenides are introduced as a viable material platform for phase change random access memory, photodetection, and the investigation of topological insulator surface states. An exponential relationship is observed between layer thickness and energy consumption during switching of 2D phase change devices, ultra-high responsivity in 2D photoresistors, and surface-rich conduction in 2D topological insulator nanoplates. Additionally, methods for the assessment of chemical purity, stoichiometry, and dimensions of …


Mixed Ligand Approach To Design Heterometallic Single-Source Precursors For Low-Temperature Preparation Of Oxide Materials, Craig Matthew Lieberman Jan 2015

Mixed Ligand Approach To Design Heterometallic Single-Source Precursors For Low-Temperature Preparation Of Oxide Materials, Craig Matthew Lieberman

Legacy Theses & Dissertations (2009 - 2024)

There is a considerable interest in the use of metal oxides for development of novel high-technological materials such as gas sensors, multiferroics, and electrocatalysts. In particular, the design of complex oxides, which incorporate more than one type of metal atom, is focused on enriching chemical and physical properties of the target materials and allowing for increased functionality. In order to replace the harsh conditions associated with traditional synthetic routes that often require high temperatures and/or pressures, new soft chemistry methods for the preparation of mixed-metal oxide materials have been developed. One of the most promising directions is the emergence of …


The Genesis And Emergence Of Community-Associated Methicillin-Resistant Staphylococcus Aureus (Ca-Mrsa): An Example Of Evolution In Action?, Alan L. Gillen, Jason Conrad, Michael Cargill Jan 2015

The Genesis And Emergence Of Community-Associated Methicillin-Resistant Staphylococcus Aureus (Ca-Mrsa): An Example Of Evolution In Action?, Alan L. Gillen, Jason Conrad, Michael Cargill

Faculty Publications and Presentations

Staphylococcus aureus infections are a common cause of disease, particularly in colonized persons. Recently, a series of published articles have reported that community-acquired methicillin-resistant S. aureus (CA-MRSA) strains are evolving and increasingly becoming prevalent in households while health care acquired MRSA (HA-MRSA) is declining in the USA. The changing superbugs have often been used as an example of evolution in action. Although MRSA infections have become increasingly reported in the community, population-based studies of students preparing for the health professions having S. aureus and MRSA colonization are lacking. During the 2014–2015 school year 544 students were tested for MRSA carriage …


Zyban, Shawna R. Meadows Jan 2015

Zyban, Shawna R. Meadows

Natural Sciences Student Research Presentations

This is a poster presented at the Natural Sciences Poster Session at Parkland College, which provides the chemical makeup, dosage, and the body's response to Zyban, or bupropion hydrochloride, a medication used to treat depression and seasonal affective disorder.


Kapvay, Russell E. Anderson Jan 2015

Kapvay, Russell E. Anderson

Natural Sciences Student Research Presentations

This is a poster presented at the Natural Sciences Poster Session at Parkland College, which provides the chemical makeup, dosage, and the body's response to Kapvay, or Clonidine Hydrochloric, a medication used to manage hypertension and in the treatment of severe pain.


Cordarone, Miriana Mccombe Jan 2015

Cordarone, Miriana Mccombe

Natural Sciences Student Research Presentations

This is a poster presented at the Natural Sciences Poster Session at Parkland College, which provides the chemical makeup, dosage, and the body's response to Cordarone, or amiodarone hydrochloride, a medication used for the treatment of ventricular arrhythmias and supraventricular arrhythmias.


Paxil, Allyson M. Hadfield Jan 2015

Paxil, Allyson M. Hadfield

Natural Sciences Student Research Presentations

This is a poster presented at the Natural Sciences Poster Session at Parkland College, which provides the chemical makeup, dosage, and the body's response to Paxil, a medication used to treat depression, obsessive-compulsive disorders, panic attacks and anxiety disorders.


Orap, Sophie A. Catlin Jan 2015

Orap, Sophie A. Catlin

Natural Sciences Student Research Presentations

This is a poster presented at the Natural Sciences Poster Session at Parkland College, which provides the chemical makeup, dosage, and the body's response to Orap, a medication used in the treatment of Tourette's syndrome.


The Link Between Adhd And Chemical Exposures, Lily Rong Jan 2015

The Link Between Adhd And Chemical Exposures, Lily Rong

Natural Sciences Student Research Presentations

A part of the Natural Sciences Poster Session at Parkland College, this poster investigates the relationship of Attention Deficit Hyperactivity Disorder to exposures to perfluorinated compounds (PFCs) and polychlorinated biphenyls (PCBs).


Boron Nitride Colloidal Solutions, Ultralight Aerogels And Freestanding Membranes Through One-Step Exfoliation And Functionalization, Weiwei Lei, Vadym Mochalin, Dan Liu, Si Qin, Yury G. Gogotsi, Ying Chen Jan 2015

Boron Nitride Colloidal Solutions, Ultralight Aerogels And Freestanding Membranes Through One-Step Exfoliation And Functionalization, Weiwei Lei, Vadym Mochalin, Dan Liu, Si Qin, Yury G. Gogotsi, Ying Chen

Chemistry Faculty Research & Creative Works

Manufacturing of aerogels and membranes from hexagonal boron nitride (h-BN) is much more difficult than from graphene or graphene oxides because of the poor dispersibility of h-BN in water, which limits its exfoliation and preparation of colloidal solutions. Here, a simple, one-step mechano-chemical process to exfoliate and functionalize h-BN into highly water-dispersible, few-layer h-BN containing amino groups is presented. The colloidal solutions of few-layer h-BN can have unprecedentedly high concentrations, up to 30 mg ml-1, and are stable for up to several months. They can be used to produce ultralight aerogels with a density of 1.4 mg cm …


Accurate Computation Of Molecular Properties From Novel Applications Of Quantum Mechanical Wavefunction Methods, James Coleman Howard Jan 2015

Accurate Computation Of Molecular Properties From Novel Applications Of Quantum Mechanical Wavefunction Methods, James Coleman Howard

Electronic Theses and Dissertations

High-accuracy quantum mechanical (qm) wavefunction methods have been applied to compute molecular properties of weakly-bound clusters. This work focuses on both extending the applicability of robust theoretical methods to larger systems and also determining the inherent accuracy of ab initio methods when compared to experimentally measured properties. Described here is the development of an efficient many-body approach that offers the ability to reduce both the time and the computational resources normally required to compute these properties reliably. The n-body:many-body qm:qm technique has been extended to compute harmonic vibrational frequencies of clusters. Applying this methodology to small hydrogen-bonded clusters demonstrates that …


Experimental And Computational Investigation Of Selected Β-Hydroxy Carbenes, Joseph D. Deangelo Jan 2015

Experimental And Computational Investigation Of Selected Β-Hydroxy Carbenes, Joseph D. Deangelo

Honors Theses

The photolytic precursor to the sterically hindered β-bis(tert)-butanol carbene, 3-(1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl)-2,2,4,4-tetramethylpentan-3-ol was prepared in three steps from phenanthrene. Photolysis of the precursor generates the desired β-hydroxy carbene, an intermediate, which subsequently rearranges into two different observed products from an intramolecular C-H insertion and alkyl shift. Four intramolecular mechanisms were ultimately considered to account for the possible rearrangement pathways. Computational studies using density functional theory are also presented.

In addition, the photolytic precursors to two cyclic β-hydroxy carbenes, 1-(1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl)cyclopropan-1-ol and 1-(1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl)cyclobutan-1-ol, were also prepared through different synthetic routes from phenanthrene. …


Enzyme-Assisted Modification Of Cellulose/Chitin Fibers With Nipaam, Anamaria Irimia, Emilia Csiszar, Marius Dobromir, Florica Doroftei, Cornelia Vasile Jan 2015

Enzyme-Assisted Modification Of Cellulose/Chitin Fibers With Nipaam, Anamaria Irimia, Emilia Csiszar, Marius Dobromir, Florica Doroftei, Cornelia Vasile

Turkish Journal of Chemistry

Coating processes are applied in order to improve coating adhesion and resistance to degradation. Covalently bound organic coatings rather than merely physically bound ones assure stable modification. In this study a novel two-step process was developed to modify cellulose/chitin mix fibers consisting of enzymatic activation with a commercial cellulase, followed by a coupling reaction with N-isopropylacrylamide (or poly (N-isopropylacrylamide)) in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS). Both enzyme-activated and subsequently modified samples were characterized by ATR-FTIR, XPS, and SEM. All obtained results confirm the structural and morphological changes of the fiber surface after the application of the two-step …


Redox Active Lipophilic Ruthenium Complexes As Potential Anti-Cancer Drugs, Nagham Alatrash Jan 2015

Redox Active Lipophilic Ruthenium Complexes As Potential Anti-Cancer Drugs, Nagham Alatrash

Chemistry & Biochemistry Dissertations - Archive

The dinuclear ruthenium(II) polypyridyl complexes (RPCs) [(phen)2Ru(tatpp)Ru(phen)2][PF6]4 (P4+) and the monomeric [(phen)2Ru(tatpp)]Cl2 (MP2+) are promising candidates for anti-cancer drug development in terms of the observed anti-tumor activity in vivo and in vitro. These complexes contain the redox-active tatpp (9,11,20,22-tetraazatetrapyrido[3,2-a:2'3'-c:3'',2''-1:2''',3''']-pentacene) ligand which seems to be the critical component for biological activity. These complexes cleave DNA when reduced in situ to a radical species. Both complexes exhibit selective cytotoxicity toward cultured malignant cell lines and showed inhibition of tumor growth in vivo. This work expands on this platform by preparing and examining more lipophilic analogues of P4+ and MP2+. Specifically, four lipophilic …


Biochemical, Kinetic And Spectroscopic Characterizations Of Non-Heme Iron Oxygenase Enzymes, Bishnu P. Subedi Jan 2015

Biochemical, Kinetic And Spectroscopic Characterizations Of Non-Heme Iron Oxygenase Enzymes, Bishnu P. Subedi

Chemistry & Biochemistry Dissertations - Archive

MiaE is a non-heme diiron enzyme which catalyzes the O2-dependent hydroxylation of selected tRNA-nucleotides as part of a multienzyme posttranscriptional hypermodification pathway. This tRNA-modifying enzyme is postulated to signal O2-availability within the pathogenic bacteria, Salmonella typhimurium. Recombinant MiaE was cloned from Salmonella typhimurium genomic DNA, purified to homogeneity, and characterized by steady-state kinetics and spectroscopic techniques (UV-visible, Circular Dichroism, dual mode electron paramagnetic resonance (EPR), and Mössbauer) for comparison to other non-heme diiron enzymes. Remarkably, regardless of the substrate used in peroxide-shunt assays, hydroxylation of the terminal isopentenyl-C4-position was observed with > 97% E-stereoselectivity. The role of tRNA-protein macromolecular interactions on …


Thiol Dioxygenases: An Investigation Into The Mechanisms Of Cysteine Dioxygenase And 3-Mercaptopropionic Acid Dioxygenase, Joshua Crowell Jan 2015

Thiol Dioxygenases: An Investigation Into The Mechanisms Of Cysteine Dioxygenase And 3-Mercaptopropionic Acid Dioxygenase, Joshua Crowell

Chemistry & Biochemistry Dissertations - Archive

Thiol dioxygenase (TDO) enzymes catalyze the molecular oxygen-dependent oxidation of sulfur containing amino acid derivatives. The loss of the ability to regulate thiols has been linked to a number of neurological diseases. Two TDO enzymes, a mammalian cysteine dioxygenase (CDO) and a bacterial 3-mercaptopropionic acid dioxygenase, are examined by probing the various effects on the steady-state kinetic parameters kcat and kcat/KM. Both of these enzymes show a similar deviation from the iconic 2-His-1-carboxylate facial triad active site motif that dominates the mononuclear non-heme iron oxidase/oxygenase class of enzymes. However, CDO shows an unusual covalently crosslinked Cys-Tyr pair within 3.3 Å …


Chemistry 102-201 General Chemistry Ii Summer 2015, Manuel I. Rodriguez Jan 2015

Chemistry 102-201 General Chemistry Ii Summer 2015, Manuel I. Rodriguez

Chemistry Courses

No abstract provided.