Physical Sciences and Mathematics Commons^™

Probing The Early Steps In The Catalytic Reduction Of Nitrite To Ammonia, Catalyzed By Cytochrome C Nitrite Reductase, Md Mahbbat Ali

Theses and Dissertations

Cytochrome c Nitrite Reductase (ccNiR) is a periplasmic, decaheme homodimeric enzyme that catalyzes the six-electron reduction of nitrite to ammonia. Under standard assay conditions catalysis proceeds without detected intermediates, and it’s been assumed that this is also true in vivo. However, this report demonstrates that in vitro it’s possible to trap putative intermediates by controlling the electrochemical potential at which reduction takes place. Such experiments provide valuable insights regarding ccNiR-catalyzed nitrite ammonification.

UV/Vis spectropotentiometry showed that nitrite-loaded Shewanella oneidensis ccNiR is reduced in a concerted 2-electron step to generate an {FeNO}7 moiety at the active site, with an associated midpoint …

Optimizing Hydrogen Sulfide Removal And Biogas Production Using The Water Wash Method, Brian Leightner

Theses and Dissertations

Biogas forms from decomposing organic material in agricultural digesters, landfills, and wastewater treatment plant digesters. Biogas is mostly composed of methane, and can be used as a carbon-based fuel. Microorganisms that consume organics in these waste streams also produce hydrogen sulfide (H2S) as part of the biogas, in varying trace amounts. H2S is corrosive to engines and pipes for machinery, a human health hazard when inhaled, and an aquatic hazard when dissolved in water. Water washing is an absorption process that dissolves hydrogen sulfide and other water soluble compounds in this process and carries it away from the gas, thereby …

Chemical Self-Assembly Strategies Toward The Design Of Molecular Electronic Circuits, Dustin Olson

Theses and Dissertations

The field of molecular electronics is generally divided into one of two major categories, the first focusing on the unique functionalization of single molecules to produce electronic behavior, the other utilizing large assemblies of molecules to produce electronic behavior. The former approach is largely attributed to the seminal paper by Aviram and Ratner in which they proposed a molecular donor-bridge-acceptor (D-B-A) type architecture could lead to single molecule rectification producing electronic effects similar to conventional semiconductor based diodes. Extensive research has been carried out in both fields as it is foreseen that new approaches to electronics miniaturization will be necessary …

Part I: A Concise Asymmetric Synthesis Of Microtubule Inhibitor Tryprostatin B Part Ii: Synthesis And Biological Assessment Of Histone Deacetylase (Hdac) Inhibitors Part Iii: Acid Catalyzed Reactions Of Aromatic Ketones With Ethyl Diazoacetate, Md Mizzanoor Rahaman

Theses and Dissertations

PART I: A CONCISE ASYMMETRIC SYNTHESIS OF MICROTUBULE INHIBITOR TRYPROSTATIN B

Tryprostatin (TPS) A and B, microtubule inhibitor, are the members of a family of prenylated Trp-Pro diketopiperzine alkaloids. These two natural products were isolated in 1995 from the fermentation broth of Aspergillus fumigatus BM939 by Osada and coworkers. TPS and related diketopiperazine containing compounds such as phenylahistins, spirotryprostatins, and cyclotryprostatins are inhibitors of the mammalian cell cycle. They prevent cell cycle progression at the G2/M phase through a unique mechanism consisting of inhibiting the interaction between microtubule assisted proteins (MAP-2) and the C-terminal end of tubulin. TPS A and …

Controlling And Manipulating Microscopic Particles In Solution By Using Various Electric Field Geometries, Xavier Sacro Udad

Theses and Dissertations

Progress in micro- and nanotechnologies depends on our capability of manipulating and interacting with microscopic particles and nanosize material. A promising approach towards this goal is the use of electric fields, which are the dominant forces at the molecular length scale. One technique for trapping nanoparticles in solution uses an externally controlled electric field, generated by two electrode pairs, to counteract the Brownian motion of a single, selected particle. Unlike other trapping tools, such as optical tweezers or magnetic tweezers, this approach scales favorably with particle size, down to the level of a single molecule. However, it depends on real-time …

The Curious Case Of Nad-Cleaving Nudix Hydrolases, Atreyei Ray

Theses and Dissertations

Nudix proteins are members of a large family of homologous enzymes that hydrolyze nucleoside diphosphates linked to other compounds (x). These enzymes have catalytic activity on a wide range of substrates such as dNTPs (both canonical and their oxidized forms), nucleotide sugars, alcohols, dinucleoside polyphosphates, dinucleotide cofactors, and nucleoside diphosphates linked to RNA. The bacterial genome encodes around 13, while the human genome encodes for 22 such nudix proteins.

The E. coli genome encodes for a mutT mutator gene, the progenitor of the family expressing the MutT pyrophosphohydrolase (NudA) protein (Treffers et al., 1954; Bhatnagar et al., 1988). The enzyme …

A Study In Molecular Recognition: Synthesis Of A Β-Sheet Mimic & Quantitation Of Metal Ions In Aqueous Solutions Through Solid Supported Semi-Selective Chemosensors, Tyler G. Fenske

Theses and Dissertations

From the hydrophobic effect, which is responsible for the organization of amphipathic molecules into cellular membranes, to the highly specific hydrogen binding patterns found in DNA base pairs that keeps our genetic material “zipped up”, non-covalent and reversible interactions are critical to properly functioning biological processes. Molecular recognition is an area of study that seeks to better understand these observed phenomena. In a general sense, association of “Host” and “Guest” molecules are based on ionic forces, hydrophobic interactions, cation-π effects, π-π stacking, conformational restriction, and many others. This dissertation will primarily focus on two projects that have an emphasis on …

In Situ Chemical Probing Of Vacancy Defects In Graphene And Boron Nitride At Room Temperature, Ali Ihsan Altan

Theses and Dissertations

IN SITU CHEMICAL PROBING OF VACANCY DEFECTS IN GRAPHENE AND BORON NITRIDE AT ROOM TEMPERATURE

by

Ali Ihsan Altan

The University of Wisconsin-Milwaukee, 2019

Under the Supervision of Professor Jian Chen

Chemical vapor deposition (CVD) has emerged as the most promising technique towards manufacturing of large area, high quality graphene. Characterization, understanding, and controlling of various structural defects in CVD-grown graphene are essential to realize its true potential for real-world applications. We report a new method for in situ chemical probing of vacancy defects in CVD-grown graphene at room temperature. Our approach is based on a solid–gas phase reaction that …

Design And Synthesis Of Achiral And Chiral Imidazodiazepine (Imdz) Gaba(A)R Subtype Selective Ligands For The Treatment Of Cns Disorders, As Well As Asthma, Guanguan Li

Theses and Dissertations

Gamma-aminobutyric acid type A receptors (GABAAR) are transmembrane pentameric ligand-gated chloride ion channels that respond to GABA, the major inhibitory neurotransmitter in the central nervous systems (CNS). The benzodiazepines (BZDs) bind at the extracellular interface of the α+γ2-subunits of GABAAR. The binding of ligands at different subunits of GABAA receptors specifically at α1-6β2/3 γ2 ion channels, can affect a wide variety of brain functions. The α1-subtype selective ion channels of GABAARs are involved in the sedative, ataxic, amnesic, anticonvulsant and addictive effects, which should be avoided, with the exception of the anticonvulsant effects, when designing ligands for this BZ allosteric …

Part I: An Investigation Of Calcitroic Acid And Its Phase Ii Conjugates. Part Ii: Toward The Development Of A Novel Orally-Available Asthma Treatment Targeting Gabaa Receptors In The Lungs, Olivia B. Yu

Theses and Dissertations

PART I

Calcitroic acid (CTA) was isolated and characterized more than four decades ago.5 Radiolabeled calcitriol (1,25-dihydroxyvitamin D3) was used at that time to enable the identification of radioactive CTA formed in vivo, which was subsequently extracted and characterized by derivatization.7 CTA was found to be predominantly formed in the liver and secreted into the gut through the bile duct via enterohepatic circulation, leading to fairly high concentrations of this metabolite of vitamin D in the intestine.8 However, assuming it was only a catabolic product of calcitriol, it was ignored thereafter.

Recently, novel experiments showed that CTA can bind the …

From General Chemistry To Anatomy And Physiology: Revalidating And Adapting Assessments And Models, Victoria Fisher

Theses and Dissertations

The 1980s saw an increasing demand for education standards that would create a scientifically literate society. In response, the American Association for the Advancement of Science (AAAS) published a report that outlined four themes that are characteristic of a scientifically literate individual: systems, models, constancy and change, and scale (1). In 1993, the AAAS published the Benchmarks for Science Literacy which outlined common scientific skills that a student should be able to demonstrate by grades 2, 5, 8, and 12 (2). Beyond the AAAS scale was not included in national science educational standards until 2012 when the National Research Council …

Part I: Design And Synthesis Of Novel Drugs To Treat Asthma By Targeting Gabaa Receptors In The Lung Part Ii: Design And Synthesis Of Novel Α2/Α3 Subtype Selective Gabaar Ligands For Cns Disorders, Rajwana Jahan

Theses and Dissertations

Part I. Asthma is a major healthcare challenge affecting an estimated 300 million people globally. Over $56 billion in asthma-related healthcare expenses occur in the United States annually. Moreover, asthma accounts for the majority of missed school/work days, Doctor and emergency room visits, and patient hospitalizations in young persons. Consequently, asthma continues to be a significant healthcare burden in terms of morbidity, productivity, and medical costs. Beta 2-adrenergic agonists and inhaled corticosteroids (ICs) are the most commonly prescribed treatments for the acute and chronic management of asthma. Both agents present efficacy, compliance, and adverse side effect concerns.

Hence, there is …

Active Polymeric Materials For 3d Shaping And Sensing, Adebola Oyefusi

Theses and Dissertations

Part I: Reprogrammable Chemical 3D Shaping for Origami, Kirigami, and Reconfigurable Molding

Origami- and kirigami-based design principles have recently received strong interest from the scientific and engineering communities because they offer fresh approaches to engineering of structural hierarchy and adaptive functions in materials, which could lead to many promising applications. Herein, we present a reprogrammable 3D chemical shaping strategy for creating a wide variety of stable complex origami and kirigami structures autonomously. This strategy relies on a reverse patterning method that encodes prescribed 3D geometric information as a spatial pattern of the unlocked phase (dispersed phase) in the locked phase …

In Situ Chemical Probing Of Vacancy Defects In Graphene And Boron Nitride At Room Temperature, Ali Ihsan Altan

Theses and Dissertations

IN SITU CHEMICAL PROBING OF VACANCY DEFECTS IN GRAPHENE AND BORON NITRIDE AT ROOM TEMPERATURE

by

Ali Ihsan Altan

The University of Wisconsin-Milwaukee, 2019

Under the Supervision of Professor Jian Chen

Chemical vapor deposition (CVD) has emerged as the most promising technique towards manufacturing of large area, high quality graphene. Characterization, understanding, and controlling of various structural defects in CVD-grown graphene are essential to realize its true potential for real-world applications. We report a new method for in situ chemical probing of vacancy defects in CVD-grown graphene at room temperature. Our approach is based on a solid–gas phase reaction that …

A Real-Time Approach To Process Monitoring Of Heavy Metals: Spectrophotometric Characterization And Application Of Novel Azo, Joseph Timothy Labeots

Theses and Dissertations

I will describe studies in developing an on-line system for process monitoring that is based upon spectrophotometric methods. Heavy metals that are discarded into the environment may pose severe threats to public health, and are thus heavily regulated. Currently, there is no reasonably affordable, reliable, real-time monitoring method for heavy metals in water. This lack of feedback for industrial applications often leads to wasted resources due to massive overtreatment to avoid costly penalties. Spectrophotometry is a viable analysis option assuming a suitable sensor molecule is available as seemingly conflicting requirements may occur. Characterization of the sensor is one of the …

Part I: An Investigation Of Calcitroic Acid And Its Phase Ii Conjugates. Part Ii: Toward The Development Of A Novel Orally-Available Asthma Treatment Targeting Gabaa Receptors In The Lungs, Olivia B. Yu

Theses and Dissertations

PART I

Calcitroic acid (CTA) was isolated and characterized more than four decades ago.5 Radiolabeled calcitriol (1,25-dihydroxyvitamin D3) was used at that time to enable the identification of radioactive CTA formed in vivo, which was subsequently extracted and characterized by derivatization.7 CTA was found to be predominantly formed in the liver and secreted into the gut through the bile duct via enterohepatic circulation, leading to fairly high concentrations of this metabolite of vitamin D in the intestine.8 However, assuming it was only a catabolic product of calcitriol, it was ignored thereafter.

Recently, novel experiments showed that CTA can bind the …