Physical Sciences and Mathematics Commons^™

Understanding Rapid Intercalation Materials One Parameter At A Time, Wessel Van Den Bergh, Morgan Stefik

Faculty Publications

Demand for fast, energy-dense storage drives the research into nanoscale intercalation materials. Nanomaterials accelerate kinetics and can modify reaction path thermodynamics, intercalant solubility, and reversibility. The discovery of intercalation pseudocapacitance has opened questions about their fundamental operating principles. For example, are their capacitor-like current responses caused by storing energy in special near-surface regions or rather is this response due to normal intercalation limited by a slower faradaic surface-reaction? This review highlights emerging methods combining tailored nanomaterials with the process of elimination to disambiguate cause-and-effect at the nanoscale. This method is applied to multiple intercalation pseudocapacitive materials showing that the timescales …

Blood Biomarkers For Mild Traumatic Brain Injury: A Selective Review Of Unresolved Issues, Daniel B. Hier, Tayo Obafemi-Ajayi, Matthew S. Thimgan, Gayla R. Olbricht, Sima Azizi, Blaine Allen, Bassam A. Hadi, Donald C. Wunsch

Biological Sciences Faculty Research & Creative Works

Background: The use of blood biomarkers after mild traumatic brain injury (mTBI) has been widely studied. We have identified eight unresolved issues related to the use of five commonly investigated blood biomarkers: neurofilament light chain, ubiquitin carboxy-terminal hydrolase-L1, tau, S100B, and glial acidic fibrillary protein. We conducted a focused literature review of unresolved issues in three areas: mode of entry into and exit from the blood, kinetics of blood biomarkers in the blood, and predictive capacity of the blood biomarkers after mTBI.

Findings: Although a disruption of the blood brain barrier has been demonstrated in mild and severe traumatic brain …

A Kinetic Model For Blood Biomarker Levels After Mild Traumatic Brain Injury, Sima Azizi, Daniel B. Hier, Blaine Allen, Tayo Obafemi-Ajayi, Gayla R. Olbricht, Matthew S. Thimgan, Donald C. Wunsch

Mathematics and Statistics Faculty Research & Creative Works

Traumatic brain injury (TBI) imposes a significant economic and social burden. The diagnosis and prognosis of mild TBI, also called concussion, is challenging. Concussions are common among contact sport athletes. After a blow to the head, it is often difficult to determine who has had a concussion, who should be withheld from play, if a concussed athlete is ready to return to the field, and which concussed athlete will develop a post-concussion syndrome. Biomarkers can be detected in the cerebrospinal fluid and blood after traumatic brain injury and their levels may have prognostic value. Despite significant investigation, questions remain as …

Visible Light Generation And Mechanistic Investigation Of High-Valent Metal-Oxo Species Supported By Different Ligands, Seth Ellis Klaine

Masters Theses & Specialist Projects

Numerous transition metal catalysts have been designed as biomimetic model compounds for the active site of metalloenzymes found throughout Nature, most notably cytochrome P450 monooxygenases that carry out the oxidative transformations of organic substrates with near-perfect chemo-, regio-, and stereo-selectivity. The primary active oxidants in catalytic and enzymatic cycles are fleeting high-valent metal-oxo intermediates where the oxo ligand can transfer to an organic substrate in a process known as oxygen atom transfer (OAT).

In the present work, porphyrin-manganese(III), salen-chromium(III), and salenmanganese( III) derivatives were successfully synthesized and spectroscopically characterized using 1H NMR and UV-Vis spectroscopies. A facile photochemical approach was …

Leaving Ligand Effects On Reactivity And Solubility Of Monofunctional Platinum(Ii) Anticancer Complexes, Heidi Linn Hruska Millay

Masters Theses & Specialist Projects

Monofunctional platinum(II) complexes, such as phenanthriplatin and pyriplatin, have notably different characteristics from the bifunctional anticancer complexes, such as cisplatin and oxaliplatin, which have detrimental toxicities and resistance associated with them. The unique properties of the monofunctional complexes may be exploited to target cancer cells without producing the toxic side effects associated with the current FDA-approved platinum-based anticancer drugs. To advance the understanding of these monofunctional platinum(II) complexes, this study replaced the chloride leaving ligand with an acetate group, which should increase solubility and alter the rate of reactivity with key amino acid and nucleotide targets. Phenanthriplatin and pyriplatin compounds …

Synthesis, Kinetic And Catalytic Studies Of Manganese Complexes With Corrole And Porphyrin Ligands, Haleh Jeddi

Masters Theses & Specialist Projects

High-valent transition metal-oxo intermediates play a significant role in the catalytic cycle of the ubiquitous cytochrome P450 enzymes and in biomimetic catalytic systems. In this work, manganese(III) porphyrin and corrole systems (2) were synthesized and characterized by UV-vis absorbance and 1H-NMR, matching literaturereported spectroscopic data. Manganese(V)-oxo corroles (3) and a manganese(IV)-oxo porphyrin (4) were successfully generated by chemical oxidation using mchloroperoxybenzoic acid (m-CPBA), and their oxidation reactions with organic reductants were comparatively investigated. Results from single-turnover kinetic studies indicate that in the tris(pentafluorophenyl)corrole system (3a), the active oxidizing intermediate differs in different solvents. The active oxidizing intermediate in acetonitrile is …

Adsorptive And Kinetic Characterization Of Aqueous Zinc Removal By Biochars, Sergio Mireles, Yongsik Ok, Chu-Lin Cheng, Jihoon Kang

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Biochars have shown a great potential to treat stormwater runoff contaminated with heavy metals due to their favorable physical and chemical characteristics. Biochar materials were produced from pyrolysis of oak tree and wood at 400C and 450C respectively, and their Zn adsorption behavior from aqueous solutions were evaluated to assess their applicability as a filter media for stormwater treatment. Two adsorption isotherm models, Freundlich and Langmuir, were used to fit the batch-scale experimental data. The kinetics of Zn adsorption was investigated under two contrasting physical condition (stagnant vs. agitated). The adsorption isotherm was better fitted with the Langmuir model (R2 …

Formation And Stability Of Atmospherically Relevant Isoprene-Derived Organosulfates And Organonitrates, Adam I. Darer, Neil C. Cole-Filipiak, Alison E. O'Connor, Matthew J. Elrod

Faculty & Staff Scholarship

Isoprene is the precursor for number of alcohol, organosulfate, and organonitrate species observed in ambient secondary organic aerosol (SOA). Recent laboratory and field work has suggested that isoprene-derived epoxides may be crucial intermediates that can explain the existence of these compounds in SOA. To confirm this hypothesis, the specific hydroxy epoxides observed in gas phase isoprene photooxidation experiments (as well as several other related species) were synthesized and the bulk phase aqueous reactions of these species in the presence of sulfate and nitrate were studied via nuclear magnetic resonance (NMR) techniques. The results indicate that both primary and tertiary organosulfates …

Microsecond Dye Regeneration Kinetics In Efficient Solid State Dye-Sensitized Solar Cells Using A Photoelectrochemically Deposited Pedot Hole Conductor, Attila J. Mozer, Dillip K. Panda, Sanjeev Gambhir, B. Winther-Jensen, Gordon G. Wallace

Faculty of Science - Papers (Archive)

Microsecond dye-regeneration kinetics was observed in efficient solid state dye-sensitized solar cells using photoelectrochemically deposited poly(3,4-ethylenedioxythiophene (PEDOT) hole conductors using transient absorption spectroscopy. The dye-regeneration rate is orders of magnitude slower than the case using the I-/I3- redox couple or commonly used small molecule hole conductor and is attributed to the low dye to PEDOT ratio within the films.

Reaction Of The C2h Radical With 1-Butyne (C4h6): Low Temperature Kinetics And Isomer-Specific Product Detection, Satchin Soorkia, Adam J. Trevitt, Talitha M. Selby, David L. Osborn, Craig A. Taatjes, Kevin R. Wilson, Stephen R. Leone

Faculty of Science - Papers (Archive)

No abstract provided.

Reactions Of The Cn Radical With Benzene And Toluene: Product Detection And Low-Temperature Kinetics, Adam J. Trevitt, Fabien Goulay, Craig A. Taatjes, David L. Osborn, Stephen R. Leone

Faculty of Science - Papers (Archive)

Low-temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165, and 295 K is found to be relatively constant over this temperature range, (3.9−4.9) × 10−10 cm3 molecule−1 s−1. These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a rate coefficient of 1.3 × 10−10 cm3 molecule−1 s−1 at 105 …

Methyl Septanoside Hydrolysis As A Measure Of Carbohydrate Ring Flexibility: Substrate Synthesis And Kinetics Analysis, Shawn Michael Miller

Honors Scholar Theses

A number of seven-membered ring systems have been found to have promising enzyme inhibiting properties. The common explanation for their efficacy is the apparent improved flexibility that the ring-system has over smaller rings. In an attempt to probe the validity of this hypothesis, unnatural seven-membered ring carbohydrates have been generated and subjected to kinetics analysis using hydrolysis. In particular, methyl α- and β-D-glycero-D-guloseptanoside were subjected to acid-catalyzed hydrolysis and monitored via HNMR experiments. The rate constants of the reactions were determined and compared to the hydrolysis rate constants of comparable pyranose carbohydrates and found to be significantly faster, indicating an …

Base-Induced Decomposition Of Alkyl Hydroperoxides In The Gas Phase. Part 3. Kinetics And Dynamics In Ho + Ch3ooh, C2h5ooh, And Tert-C4h9ooh Reactions, Shuji Kato, G Barney Ellison, Veronica Bierbaum, Stephen J. Blanksby

Faculty of Science - Papers (Archive)

The E_CO2 elimination reactions of alkyl hydroperoxides proceed via abstraction of an α-hydrogen by a base: X⁻ + R¹R²HCOOH → HX + R¹R²CO + HO⁻. Efficiencies and product distributions for the reactions of the hydroxide anion with methyl, ethyl, and tert-butyl hydroperoxides are studied in the gas phase. On the basis of experiments using three isotopic analogues, HO⁻ + CH₃OOH, HO⁻ + CD₃OOH, and H¹⁸O⁻ + CH₃OOH, the overall intrinsic reaction efficiency is determined to …

Crystal Structure Of The Gtpase Domain Of Rat Dynamin 1, Thomas F. Reubold, Susanne Eschenburg, Andreas Becker, Marilyn Leonard, Sandra L. Schmid, Richard B. Vallee, F. Jon Kull, Dietmar J. Manstein

Dartmouth Scholarship

Here, we present the 1.9-A crystal structure of the nucleotide-free GTPase domain of dynamin 1 from Rattus norvegicus. The structure corresponds to an extended form of the canonical GTPase fold observed in Ras proteins. Both nucleotide-binding switch motifs are well resolved, adopting conformations that closely resemble a GTP-bound state not previously observed for nucleotide-free GTPases. Two highly conserved arginines, Arg-66 and Arg-67, greatly restrict the mobility of switch I and are ideally positioned to relay information about the nucleotide state to other parts of the protein. Our results support a model in which switch I residue Arg-59 gates GTP binding …

Characterization Of Polycyclic Aromatic Hydrocarbons (Pahs) By The Kinetics Of Depuration In Bivalve Molluscs, Mercenaria Mercenaria, C Sato, H Kim, John T. Tanacredi Ph.D.

Faculty Works: CERCOM

The objectives of this study were to examine depuration aspects of polycyclic aromatic hydrocarbons (PAHs) in a hard-shell clam Mercenaria mercenaria, and to characterize PAHs by the depuration kinetics. In this investigation, clams were exposed to artificial sea water containing a mixture of eight PAHs (i.e., naphthalene, fluorene, phenanthrene, flouranthene, pyrene, benz[a]anthracene, chrysene, benzo[a]pyrene) for 48 hours. The clams were then transferred into clean (PAH-free) artificial seawater for release, and sampled at predetermined intervals. The target PAHs were extracted from the clam tissue and quantified by a gas chromatograph equipped with a capillary glass column and FID.

The results …