Chemistry Commons^™

Quantum Critical Transition Amplifies Magnetoelastic Coupling In Mn[N(Cn)(2)](2), T V. Brinzari, P Chen, Q C. Sun, J Liu, L C. Tung, Y Wang, J A. Schlueter, J Singleton, Jamie L. Manson, M H. Whangbo, A P. Litvinchuk, J L. Musfeldt

Chemistry and Biochemistry Faculty Publications

We report the discovery of a magnetic quantum critical transition in Mn[N(CN)(2)](2) that drives the system from a canted antiferromagnetic state to the fully polarized state with amplified magnetoelastic coupling as an intrinsic part of the process. The local lattice distortions, revealed through systematic phonon frequency shifts, suggest a combined MnN6 octahedra distortion + counterrotation mechanism that reduces antiferromagnetic interactions and acts to accommodate the field-induced state. These findings deepen our understanding of magnetoelastic coupling near a magnetic quantum critical point and away from the static limit.

Identification Of Cisplatin-Binding Proteins Using Agarose Conjugates Of Platinum Compounds, Takatoshi Karasawa, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger

Chemistry Faculty Publications and Presentations

Cisplatin is widely used as an antineoplastic drug, but its ototoxic and nephrotoxic side-effects, as well as the inherent or acquired resistance of some cancers to cisplatin, remain significant clinical problems. Cisplatin’s selectivity in killing rapidly proliferating cancer cells is largely dependent on covalent binding to DNA via cisplatin’s chloride sites that had been aquated. We hypothesized that cisplatin’s toxicity in slowly proliferating or terminally differentiated cells is primarily due to drug-protein interactions, instead of drug-DNA binding. To identify proteins that bind to cisplatin, we synthesized two different platinum-agarose conjugates, one with two amino groups and another with two chlorides …

Laughlin '14 Selected As Nsf Scholar, Mallika Kavadi

News and Events (Discontinued Series)

No abstract provided.

Flow-Tube Oxidation Experiments On The Carbon Preform Of Pica, Francesco Panerai, Alexandre Martin, Nagi N. Mansour, Steven A. Sepka, Jean Lachaud

Mechanical Engineering Faculty Publications

Oxidation experiments on the carbon preform of a phenolic-impregnated carbon ablator were performed in the NASA Ames ow-tube reactor facility, at temperatures between 700 and 1300 K, under dry air gas at pressures between 103 and 104 Pa. Mass loss, volumetric recession and density changes were measured at different test conditions. An analysis of the diffusion/reaction competition within the porous material, based on the Thiele number, allowed us to identify low temperature and low pressure conditions to be dominated by in-depth volume oxidation. Experiments above 1000 K were found at transition conditions, where diffusion and reaction occur at similar scales. …

Aquifer Characterization And Quantitative Assessment Of Over Exploitation Of The Shallow Aquifer In Al Maqam Al Saad Area, The Eastern Region, Abu Dhabi Emirate, Ismail Mohammed Hamad Ai Badi

Theses

Al Maqam-AI Saad area is located to the west of Al Ain city on Al Ain-Abu Dhabi Highway. This area was chosen to be studied because of the rapid decline of the water levels in the shallow aquifer as a result of continuous heavy withdrawal of the ground water. In 1990-1991, the area was recognized as one of the major ground water depressions in the Eastern Region where more than 40 meters of draw down were noted in the center of depression. The objective of this study is to determine the hydraulic status of the aquifer by means of characterization …

Latent Cysteine Residues From Polymers Prepared Via Free And Controlled Radical Polymerizations, Douglas Vincent Amato

Master's Theses

One less commonly used “click” reaction is thiazolidine chemistry. Thiazolidine chemistry is a commonly used reaction used in biological systems because the reaction requires the presence of both cysteine (a common amino acid) and an aldehyde or ketone. If cysteine residues could be incorporated into a polymer then a variety of applications could be developed. Polymers containing free thiols (aka thiomers) have developed in the last decade to become great mucoadhesives. If there was a facile route to control the amount of free thiols along the polymer then more fine-tuned and potentially stronger adhesives could be made. For these reasons …

A Phase 1 Study Of Trc102, An Inhibitor Of Base Excision Repair, And Pemetrexed In Patients With Advanced Solid Tumors, Michael S. Gordon, Lee S. Rosen, David Mendelson, Ramesh K. Ramanathan, Jonathan Goldman, Lili Liu, Yan Xu, Stanton L. Gerson, Stephen P. Anthony, William D. Figg, Shawn Spencer, Bonne J. Adams, Charles P. Theuer, Bryan R. Leigh, Glen J. Weiss

Chemistry Faculty Publications

Introduction TRC102 potentiates the activity of cancer therapies that induce base excision repair (BER) including antimetabolite and alkylating agents. TRC102 rapidly and covalently binds to apurinic/apyrimidinic (AP) sites generated during BER, and TRC102-bound DNA causes topoisomerase II-dependent irreversible strand breaks and apoptosis. This study assessed the safety, maximum-tolerated dose (MTD), pharmacokinetics and pharmacodynamics of TRC102 alone and in combination with pemetrexed. Purpose Patients with advanced solid tumors received oral TRC102 daily for 4 days. Two weeks later, patients began standard-dose pemetrexed on day 1 in combination with oral TRC102 on days 1 to 4. The pemetrexed-TRC102 combination was repeated every …

2,2',5',6-Tetrachloro-4-[(1S)-1-Methylpropoxy]Biphenyl, Hans-Joachim Lehmler, Huimin Wu, Sean Parkin

Chemistry Faculty Publications

In the title molecule, C₁₆H₁₄Cl₄O, the dihedral angle between the least-square planes of the benzene rings is 84.40 (7)°. No unusual intermolecular interactions are present.

Unraveling The Activation Mechanism Of The Potato Tuber Adp-Glucose Pyrophosphorylase, Carlos M. Figueroa, Misty L. Kuhn, Christine A. Falaschetti, Ligin Solamen, Kenneth W. Olsen, Miguel Ballicora, Alberto A. Iglesias

Chemistry: Faculty Publications and Other Works

ADP-glucose pyrophosphorylase regulates the synthesis of glycogen in bacteria and of starch in plants. The enzyme from plants is mainly activated by 3-phosphoglycerate and is a heterotetramer comprising two small and two large subunits. Here, we found that two highly conserved residues are critical for triggering the activation of the potato tuber ADP-glucose pyrophosphorylase, as shown by site-directed mutagenesis. Mutations in the small subunit, which bears the catalytic function in this potato tuber form, had a more dramatic effect on disrupting the allosteric activation than those introduced in the large subunit, which is mainly modulatory. Our results strongly agree with …

Re-Healable Coating Based Upon Thermally Responsive Linkages, Dahlia Ningrum Amato

Master's Theses

The goal of this thesis was to design thermally responsive polyol resins that would be compatible with isocyanates. Two approaches were made to reach this goal, the first involved functionalizing soybean oil and the second involved post-polymerization modification of a methacrylate based resin.

A soybean based coating with thermally responsive Diels-Alder linkages has been prepared following an automotive two-component formulation. The resulting coatings displayed the capability to be healed following physical deformation by a thermal stimulus, and such a material has significant potential for end users. Various curing agents were employed, and resulted in variation of scratch resistance and re-healablity. …

Stability And Precipitation Of Diverse Nanoparticles, Chintal Desai

Dissertations

Nanotechnology is a rapidly growing industry that is exploiting the novel characteristics of materials manufactured at the nanoscale. Carbon based nanomaterials such as Carbon Nanotubes (CNTs) and Detonation Nanodiamond (DND) possess unique properties and find a wide range of industrial applications. With the advent of mass production of such materials, there is a possibility of contamination of water resources. Depending on the surface properties and structures, they might aggregate and settle down, or be dispersed and transported by the water. Therefore, there is a need to develop an understanding of the fate of such materials in aqueous media. The understanding …

Application Of Hydrogen Peroxide As Brown Tide Bloom Control Agent, Varunpreet Randhawa

Dissertations

Harmful algal blooms (HABs) are growing problem across the globe. One such HAB that’s recurring in the coastal waters of New York and New Jersey since mid-1980s, and has been reported in other countries recently, is brown tide bloom. The causal organism is a minute pel agophyte (cell diameter ~- 2µ m) Aureococcus anophagefferens. The brown tide bloom has been responsible for the severe ecological damage and economic loss (e.g. shellfishery) in the affected areas. This research focuses on finding a method to control brown tide blooms and explores the potential of natural chemical biocide hydrogen peroxide (H_{2 …}

Study Of Elementary Reactions Of Combustion Importance At Elevated Temperatures And Pressures, Manuvesh Sangwan

Dissertations

The aim of the present study is to study the kinetics of elementary reactions of combustion importance at elevated temperatures and pressures. High pressure is encountered in many systems of practical importance such as internal combustion engines and rocket combustion chambers. Several reactions of OH, CH₃ and HO₂ radicals are studied. The pressure range covered in this study is 1 - 100 bar and the temperature range is 292 - 834 K. The experimental approach used is laser photolysis coupled to UV transient absorption spectroscopy. A unique high pressure heatable flow reactor is employed and a novel approach …

Escherichia Coli 2-Oxoglutarate Dehydrogenase Multienzyme Complex: E1 And E2 Substrate Specificty, E1 Carboligase Activity, And E2 Interchain Succinyl Transfer, Da Jeong Shim

Dissertations

Escherichia coli (E. coli) 2-oxoglutarate dehydrogenase multienzyme complex (OGDHc) contains three components: a thiamin di phosphate (ThD P) dependent 2-oxogl utarate dehydrogenase (E1 o), a di hydrol i poylsucci nyl transferase (E2o), and a di hydrol i poyl dehydrogenase (E3). The first two components carry out the principal reactions for succinyl CoA formation while the third one reoxidizes dihydrolipoamide to lipoamide. This mechanism is similar to other 2-oxoacid dehydrogenase complexes, including pyruvate dehydrogenases (PDHc) and branched-chain dehydrogenases.

E1o of the E. coli OGDHc was engineered to accept unnatural substrates. The natural substrate for E1 o is 2-oxogl utarate …

Computational Thermochemistry Of Hydrocarbons, Oxygenates, Cyclic Alkanes, And Furans, Jason Michael Hudzik

Dissertations

Fundamental thermochemical properties including enthalpies (ΔH°_{f 298}), entropies (S° (T)), heat capacities (C_p(T)), and bond dissociation energies (BDEs) for several common and complex hydrocarbon fuel species are determined using computational chemical methods. ΔH° _{f 298} values are calculated using work reactions with the B3LY P (6-31 G(d,p) and 6-311G(2d,2p) basis sets), CBS-QB3, and G3MP2B3 calculation methods. Structures, moments of inertia, vibrational frequencies, and internal rotor potentials are calculated for contributions to entropies and heat capacities. Kinetic rate parameters are calculated for hydrogen abstraction and chemical activation reactions.

Recommended ΔH° …

Interactions Of Zn2+ On Insulin Oligomer Formation, Stability, And Fragmentation: Analysis Using Esi-Im-Ms, Tiffany Culver

Honors Theses

Insulin is a hormone protein essential to the regulation of blood sugar levels. Although it is active as a hormone in the monomer (single insulin unit) form, it is stored in the pancreas as a hexamer – a coordination of six insulin units and zinc ions. This research analyzes the effects of zinc ions on the formation, stability, and fragmentation of the hexamer and other oligomer species in varying solution and instrument conditions, including the ability of the higher oligomers to transfer from crystallization to solution to a gas phase for analysis using electrospray ionization ion mobility mass spectrometry (ESI-IM-MS). …

Photoionization Mass Spectrometry And Photoelectron-Photoion Coincidence (Pepico) Spectroscopy Studies Of Select Biofuel Molecules, Joseph G. Czekner

Master's Theses

This thesis is the culmination of numerous experiments, performed on two different continents, investigating the spectroscopic and thermodynamic properties of several biofuels and fuel additives. It will start with an introduction about the motivation behind these experiments. The second chapter will outline the experimental details of the apparatus at the Advanced Light Source (ALS) in Berkeley, CA, followed by the Swiss Light Source (SLS) in Villigen, Switzerland. Third, the theoretical concepts and data analysis methods will be discussed in detail.

Chapter 4 will be the start of the newly obtained data. It presents some photoionization mass spectrometry studies on γ-valerolactone …

Identification Of An Active Site-Bound Nitrile Hydratase Intermediate Through Single Turnover Stopped-Flow Spectroscopy, Natalie Gumataotao, Misty L. Kuhn, Natalia Hajnas, Richard C. Holz

Chemistry Faculty Research and Publications

Stopped-flow kinetic data were obtained for the iron-type nitrile hydratase from Rhodococcus equi TG328-2 (ReNHase) using methacrylonitrile as the substrate. Multiple turnover experiments suggest a three-step kinetic model that allows for the reversible binding of substrate, the presence of an intermediate, and the formation of product. Microscopic rate constants determined from these data are in good agreement with steady state data confirming that the stopped-flow method used was appropriate for the reaction. Single turnover stopped-flow experiments were used to identify catalytic intermediates. These data were globally fit confirming a three-step kinetic model. Independent absorption spectra acquired between 0.005 …

The Mathematics Of A Successful Deconvolution: A Quantitative Assessment Of Mixture-Based Combinatorial Libraries Screened Against Two Formylpeptide Receptors, Radleigh Santos, Jon R. Appel, Marc Giulianotti, Bruce S. Edwards, Larry A. Sklar, Richard A. Houghten, Clemencia Pinilla

Mathematics Faculty Articles

In the past 20 years, synthetic combinatorial methods have fundamentally advanced the ability to synthesize and screen large numbers of compounds for drug discovery and basic research. Mixture-based libraries and positional scanning deconvolution combine two approaches for the rapid identification of specific scaffolds and active ligands. Here we present a quantitative assessment of the screening of 32 positional scanning libraries in the identification of highly specific and selective ligands for two formylpeptide receptors. We also compare and contrast two mixture-based library approaches using a mathematical model to facilitate the selection of active scaffolds and libraries to be pursued for further …

Polymerized Hemin As An Electrocatalytic Platform For Peroxynitrite's Oxidation And Detection, Serban F. Peteu, Tiyash Bose, Mekki Bayachou

Chemistry Faculty Publications

Peroxynitrite (ONOO−) constitutes a major cytotoxic agent, implicated in a host of pathophysiological conditions, thereby stimulating a tremendous interest in evaluating its role as an oxidant in vivo. Some of the detection methods for peroxynitrite include oxidation of fluorescent probes, EPR spectroscopy, chemiluminescence, immunohistochemistry, and probe nitration; however, these are more difficult to apply for real-time quantification due to their inherent complexity. The electrochemical detection of peroxynitrite is a simpler and more convenient technique, but the best of our knowledge there are only few papers to date studying its electrochemical signature, or reporting amperometric microsensors for peroxynitrite. Recently, we have …

Surface Tethered Pamam Dendrimers On Controlled Pore Glass As Color Release Sensors For Phosphates, Chang Liu

Master's Theses

Poly(amidoamine) dendrimer (PAMAM) are highly branched macromolecules with reactive amine groups in their interior and exterior. PAMAM dendrimers were attached to controlled pore glass (CPG) surfaces in order to create new functionalized surfaces and used as platforms for UV-vis and fluorescent sensing of phosphate substrates via indicator displacement assays (IDA).

CPG surfaces were first modified with different sized PAMAM dendrimers (generation 3.0, 4.0, and 5.0), then reacted with two strong metal-chelators: aminofunctionalized terpyridine (synthesized from 2,2’:6’,2’’-terpyridine) and Nα-Nα-bis(carboxymethyl)-L-lysine (Lys-NTA). First of all, Cu(II) metal ion binding capacities were measured on the surfaces. Second, two terminal group density tests, amine assay …

Flower-Shaped Nanoparticles Improve Sensitivity Of Chemical Detection, Vladimir Kitaev, Nicole Ritter (Nee Cathcart)

Clear Language Summaries

What you need to know: Raman spectroscopy can be enhanced to be more sensitive in detecting chemicals through the use of nanoparticles with sharper edges and cavities. Silver nanoparticle “flowers” developed at Laurier show the most promising results for the optimal enhancement of this diagnostic testing.

The Cyclomodulin Cycle Inhibiting Factor (Cif) Alters Cullin Neddylation Dynamics, Tasha B. Toro, J. I. Toth, M. D. Petroski

Faculty and Staff Publications

The bacterial effector protein cycle inhibiting factor (CIF) converts glutamine 40 of NEDD8 to glutamate (Q40E), causing cytopathic effects and inhibiting cell proliferation. Although these have been attributed to blocking the functions of cullin-RING ubiquitin ligases, how CIF modulates NEDD8-dependent signaling is unclear. Here we use conditional NEDD8-dependent yeast to explore the effects of CIF on cullin neddylation. Although CIF causes cullin deneddylation and the generation of free NEDD8 Q40E, inhibiting the COP9 signalosome (CSN) allows Q40E to form only on NEDD8 attached to cullins. In the presence of the CSN, NEDD8 Q40E is removed from cullins more rapidly than …

Targeting Udp-Galactopyranose Mutases From Eukaryotic Human Pathogens, Karina Kizjakina, John J. Tanner, Pablo Sobrado

Chemistry Faculty Research & Creative Works

UDP-Galactopyranose mutase (UGM) is a unique flavin-dependent enzyme that catalyzes the conversion of UDPgalactopyranose (UDP-Galp) to UDP-galactofuranose (UDP-Galf). The product of this reaction is the precursor to Galf, a major component of the cell wall and of cell surface glycoproteins and glycolipids in many eukaryotic and prokaryotic human pathogens. The function of UGM is important in the virulence of fungi, parasites, and bacteria. Its role in virulence and its absence in humans suggest that UGM is an ideal drug target. Significant structural and mechanistic information has been accumulated on the prokaryotic UGMs; however, in the past few years the research …

Measuring Learning Gains In Chemical Education: A Comparison Of Two Methods, Thomas C. Pentecost, Jack Barbera

Peer Reviewed Articles

Evaluating the effect of a pedagogical innovation is often done by looking for a significant difference in a content measure using a pre−post design. While this approach provides valuable information regarding the presence or absence of an effect, it is limited in providing details about the nature of the effect. A measure of the magnitude of the pre−post change, commonly called learning gain, could provide this additional information to chemical education researchers. In this paper, we compare two methods of measuring learning gains using data from large-scale administrations of the Chemical Concepts Inventory at four universities. The intent of this …

Probing The Low Temperature Oxidation Of Furanic Biofuels, 2-Methyltetrahydrofuran And 2,5-Dimethylfuran, Utilizing Orthogonal Time-Of-Flight Mass Spectrometry Coupled To Synchrotron Radiation, Matthew Mcmanus

Master's Theses

Concern over natural resources and global climate shifts has increased the focus of sourcing transportation fuels from depleting oil wells to regenerative, biological based solutions. One avenue of biologically sourced fuel involves the extraction of C5 and C6 sugars from the woody, fibrous, and inedible plant materials, otherwise known as lignocellulosic biomass. These cellulosic sugars can be converted to target biofuels and biofuel additives like the furanic compounds, 2,5-dimethylfuran and 2-methylfuran. In this thesis, the low temperature oxidation of two compounds, 2,5-dimethylfuran and 2-methylfuran, are explored. These reactions were conducted at the Advanced Light Source in Berkeley, CA and used …

Synthesis And Characterization Of Luminescent Cyclic Germanium Compounds, Teresa Lynn Bandrowsky

Dissertations

The vision in the field of organic electronics is the realization of flexible, easily manufactured, low cost optoelectronics for use in organic light emitting diodes (OLEDs) for large area displays and lighting applications, organic photovoltaic cells, and organic field-effect transistors. The active layers within such devices are composed of semiconducting small molecules or polymers. The rich chemistry of new π-conjugated materials holds the key to continued progress by allowing the material properties of organic semiconductors to be readily tuned towards application specific demands. At the core of this subject matter is how to modify the electronic structures of π-conjugated molecules …

The Investigation Of Iron(Ii) Complexes And Their Catalytic Applications, Matthew Joseph Lenze

Dissertations

Several new η5-indenyl (Ind) complexes of iron featuring phosphinooxazoline (PHOX) ligands were synthesized and spectroscopically characterized and in a few cases structurally. The complexes were synthesized using phosphinooxazoline ligands and the corresponding iron precursor [Fe(η5-Ind) I(CO)2], yielding novel piano-stool iron complexes of the general formula [Fe(η5-Ind)(CO)(PHOX)]+ in 73% to 81% isolated yields. The complexes were tested for their efficacy in a carbon-carbon bond formation known as the Mukaiyama aldol reaction. The [Fe(η5-Ind)(CO)(PHOX)]+ complexes were capable of activating the carbonyl of aromatic aldehydes towards by attack 1-(tertbutyldimethylsilyloxy)-1-methoxyethene to form the expected silyl protected β-hydroxyesters. In these complexes, the η5-η3 haptotropic shift …

Isolation, Characterization And Synthesis Of Asthma Inducing Fungal Glycolipid And Analytical Method Development For Novel Antimicrobial Peptide Mimics, Vinod Chaudhary

Theses and Dissertations

NKT cells are an important part of human immune system and recognize a specific set of antigens called glycolipids. Only a handful of "natural" NKT cell antigens are known till date. Although NKT cells play a protective role against pathogenic organisms, imbalances in NKT cell functions are implicated in many diseases including asthma. Allergic asthma, a Th2 driven inflammation of airways, is primarily caused by inhalation of environmental allergens. In the last decade, inhaled allergen Aspergillus fumigatus has been under scrutiny for the presence of NKT cell antigens that might trigger asthma. We successfully isolated, characterized and synthesized a "natural" …

Topography-Guided Spreading And Drying Of 6,13-Bis(Triisopropylsilylethynyl)-Pentacene Solution On A Polymer Insulator For The Field-Effect Mobility Enhancement, Chang-Min Keum, Jin-Hyuk Bae, Min-Hoi Kim, Hea-Lim Park, Marcia M. Payne, John E. Anthony, Sin-Doo Lee

Chemistry Faculty Publications

We report on the enhancement of the field-effect mobility of solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) by unidirectional topography (UT) of an inkjet-printed polymer insulator. The UT leads to anisotropic spreading and drying of the TIPS-pentacene droplet and enables to spontaneously develop the ordered structures during the solvent evaporation. The mobility of the UT-dictated TIPS-pentacene film (0.202 ± 0.012 cm²/Vs) is found to increase by more than a factor of two compared to that of the isotropic case (0.090 ± 0.032 cm²/Vs). The structural arrangement of the TIPS-pentacene molecules in relation to the mobility enhancement is described within an …