Chemistry Commons^™

Chiral Magnetization Configurations In Magnetic Nanostructures In The Presence Of Dzyaloshinski-Moriya Interactions, Naoise Grisewood, John Eves, Timothy Usher, Hans-Benjamin Braun

Physics Faculty Publications

Many low-dimensional systems, such as nanoscale islands, thin films, and multilayers, as well as bulk systems, such as multiferroics, are characterized by the lack of inversion symmetry, a fact that may give rise to a Dzyaloshinskii-Moriya (DM) interaction. For sufficient strength, the DM interaction will favor spiral spin configurations of definite chirality. In order to harness such systems for applications, it is important to understand the conditions under which these spiral spin configurations form and how they can be controlled via an external field. Here, we present exact solutions of the 1D magnetization profiles in such systems for arbitrary material …

De Meo Carries On Tradition Of Teaching Chemistry, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Ua94/6/11 Student / Alumni Personal Papers Wku Darwin Newton, Wku Archives

WKU Archives Collection Inventories

Notebooks, notes and papers written by Darwin Newton during his time as a student at WKU.

Evaluation Of Dft Methods To Study Reactions Of Benzene With Oh Radical, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Several density functional theory” (DFT) methods are applied to two different reaction channels involving OH• + C6H6, and the results compared with high-level ab initio calculations. The OH• adds directly to one C atom in the first channel, first forming an encounter complex with the OH• poised above the aromatic plane. B3LYP, BH&HLYP, and MPW1K compute an accurate estimate of the overall exothermicity, whereas M05-2X, PBE0, and PBEPBE overestimate this quantity to some degree. With the exceptions of PBEPBE and PBE0, the other methods produce an acceptable barrier to addition. All approaches except BH&HLYP correctly predict an exothermic H• abstraction, …

Structural Polymorphism In Tau Filaments: An Implication For Neurodegenerative Diseases, Ayisha Siddiqua

Electronic Theses and Dissertations

Tau filaments are the pathological hallmark of >20 neurodegenerative diseases including Alzheimer's disease, Pick's disease, and progressive supranuclear palsy. In the adult human brain, six isoforms of tau are expressed that differ by presence or absence of the second of the four semiconserved repeats. As a consequence, half of the tau isoforms have three repeats (3R tau), whereas the other half has four repeats (4R tau).

Site-directed spin labeling of recombinant tau in conjunction with electron paramagnetic resonance spectroscopy was used to obtain structural insights into tau filaments. The studies showed that the filaments of 4R tau and 3R tau …

The Golden Pathway To Thiolate-Stabilized Nanoparticles: Following The Formation Of Gold (I) Thiolate From Gold (Iii) Chloride, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

Pathways for the formation of gold thiolate complexes from gold(III) chloride precursors AuCl₄^– and AuCl₃ are examined. This work demonstrates that two distinct reaction pathways are possible; which pathway is accessible in a given reaction may depend on factors such as the residue group R on the incoming thiol. Density functional theory calculations using the BP86 functional and a polarized triple-ζ basis set show that the pathway resulting in gold(III) reduction is favored for R = methyl. A two-to-one ratio of thiol or thiolate to gold can reduce Au(III) to Au(I), and a three-to-one ratio can lead …

Carbon(Sp3)-Fluorine Bond-Forming Reductive Elimination From Palladium(Iv) Complexes., J. Brannon Gary

Faculty Publications

The development of transition-metal-catalyzed reactions for the formation of CF bonds has been an area of intense research over the past decade.[1–3] Traditionally, the CF coupling step of these sequences has proven challenging because of the high kinetic barrier for CF bond-forming reductive elimination from most transition-metal centers.[1] Our approach to address this challenge has involved the use of PdII catalysts in conjunction with F+-based oxidants. Since 2006, a variety of PdII-catalyzed reactions of F+ reagents have been developed to introduce fluorine at both C(sp2 ) and C(sp3 ) centers.[4–6] These transformations have been proposed to proceed through CF bond-forming …

Microwave, Infrared And Raman Spectra, R0 Structural Parameters, Ab Initio Calculations And Vibrational Assignment Of 1-Fluoro-1-Silacyclopentanea), James R. Durig, Savitha S. Panikar, Daniel A. Obenchain, Brandon J. Bills, Patrick M. Lohan, Rebecca A. Peebles, Sean A. Peebles, Peter Groner, Gamil A. Guirgis, Michael D. Johnston

Faculty Research and Creative Activity

The microwave spectrum (6500–18 500 MHz) of 1-fluoro-1-silacyclopentane, c-C4H8SiHF has been recorded and 87 transitions for the 28Si, 29Si, 30Si, and 13C isotopomers have been assigned for a single conformer. Infrared spectra (3050-350 cm−1) of the gas and solid and Raman spectrum (3100-40 cm−1) of the liquid have also been recorded. The vibrational data indicate the presence of a single conformer with no symmetry which is consistent with the twist form. Ab initio calculations with a variety of basis sets up to MP2(full)/aug-cc-pVTZ predict the envelope-axial and envelope-equatorial conformers to be saddle points with nearly the same energies but much …

Characterization And Electrochromic Properties Of Poly(2,3,5,6-Tetrafluoroaniline): Progress Towards A Transparent Conducting Polymer, Lavinia Astratine, Edmond Magner, John Cassidy, Tony Betts

Articles

Electrochromic films of poly(2,3,5,6-tetrafluoroaniline) (PTFA) were formed on ITO substrates from aqueous solutions utilising perchloric acid (HClO₄) as dopant. Electrochemical and spectroscopic characterization of PTFA films was performed in background electrolyte and in solutions with the addition of tetrahydrofuran. When the PTFA film was removed from its growth medium, a significant decrease in the faradaic current was observed. The faradaic response increased on addition of tetrahydrofuran which facilitates ion movement through the polymer matrix. PTFA films deposited on ITO substrate were orange and light orange in the oxidized and reduced forms, respectively. The films were ca. 25 nm …

Β-Casein–Phospholipid Monolayers As Model Systems To Understand Lipid–Protein Interactions In The Milk Fat Globule Membrane, Sophie Gallier, Derek E. Gragson, Rafael Jiménez-Flores, David W. Everett

Chemistry and Biochemistry

Phospholipid–protein monolayer films were studied as model systems to mimic the structure of the native bovine milk fat globule membrane (MFGM) and to understand lipid–protein interactions at the surface of the globule. Phospholipids extracted from bovine raw milk, raw cream, processed milk and buttermilk powder were spread onto the air–water interface of a Langmuir trough, β-casein was then added to the sub-phase, and Langmuir–Blodgett films were studied by epifluorescence microscopy and atomic force microscopy. In all films, β-casein was responsible for clustering of the sphingomyelin- and cholesterol-rich microdomains into larger platforms. This suggests that the same phenomenon may happen at …

Kinetic Models Of The Prebiotic Replication Of Dsrna Under Thermal Cycling Conditions, Pauline Schwartz, Dante M. Lepore, Carl Barratt

Chemistry and Chemical Engineering Faculty Publications

We present computational models for the replication of double stranded RNA (dsRNA) or related macromolecules under thermal cycling conditions that would reflect prebiotic (i.e. non-enzymatic) environments. Two models of the replication of dsRNA are represented as multi-step chemical systems. The objective of this investigation was to better understand the kinetic features of such chemical systems. It is shown that thermal cycling in a chemical system is advantageous (relative to a fixed temperature) if there are two competing reactions, one favored at high temperature and one favored at low temperature. For the prebiotic replication of dsRNA, a high temperature favors formation …

Contributions Of Various Noncovalent Bonds To The Interaction Between An Amide And S-Containing Molecules, U. Adhikari, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

N-Methylacetamide, a model of the peptide unit in proteins, is allowed to interact with CH3SH, CH3SCH3, and CH3SSCH3 as models of S-containing amino acid residues. All of the minima are located on the ab initio potential energy surface of each heterodimer. Analysis of the forces holding each complex together identifies a variety of different attractive forces, including SH⋅⋅⋅O, NH⋅⋅⋅S, CH⋅⋅⋅O, CH⋅⋅⋅S, SH⋅⋅⋅π, and CH⋅⋅⋅π H-bonds. Other contributing noncovalent bonds involve charge transfer into σ* and π* antibonds. Whereas some of the H-bonds are strong enough that they represent the sole attractive force in several dimers, albeit not usually in the …

Structure And Reversible Pyran Formation In Molybdenum Pyranopterin Dithiolene Models Of The Molybdenum Cofactor, Benjamin R. Williams, Yichun Fu, Glen P. A. Yap, Sharon J. Nieter Burgmayer

Chemistry Faculty Research and Scholarship

The syntheses and X-ray structures of two molybdenum pyranopterin dithiolene complexes in biologically relevant Mo(+4) and Mo(+5) states are reported. Crystallography reveals these complexes possess a pyran ring formed through a spontaneous cyclization reaction of a dithiolene side-chain hydroxyl group at a C=N bond of the pterin. NMR data on the Mo(+4) complex suggests a reversible pyran ring cyclization occurs in solution. These results provide experimental evidence that the pyranopterin dithiolene ligand in molybdenum and tungsten enzymes could participate in catalysis through dynamic processes modulated by the protein.

Diabetic Ketoacidosis, Thanaporn Chittiphalungsri

Natural Sciences Student Research Presentations

This poster describes the causes, diagnosis, and treatment of diabetic ketoacidosis.

Linus Pauling: Scientist Of The 20th Century, Laura Ward

Natural Sciences Student Research Presentations

This poster describes the contributions scientist Linus Pauling made to the fields of chemistry and molecular biology, including his hybridization theory.

Development Of An Electrospary Ionization Source And Vacuum Interface For Guided Ion Beam Tandem Mass Spectrometry Experiments: Structural And Energetic Effects In The Molecular Recognition Of Amino Acids By 18-Crown-6, Yu Chen

Wayne State University Dissertations

Absolute 18-crown-6 (18C6) binding affinities of the side chains of AAs in peptides and proteins were determined in a step by step fashion using guided ion beam tandem mass spectrometry techniques. Firstly, 18C6 binding affinities of several peptidomimetic bases (B) that serve as mimics of the side chains of Lys, Arg, and His and n-terminal amino group have been examined to provide initial estimates of the 18C6 binding affinities of the side chains of AAs. The Bs were extended to natural occurring AAs and further extended to acetylated AAs (AcAA) to determine the binding affinities of the side chains of …

Design And Synthesis Of Antithrombotic Liposomal Protein Conjugate, Hailong Zhang

ETD Archive

Recent advances in the molecular bases of haemostasis have highlighted that endothelial thrombomodulin (TM) plays a critical role in local haemostasis by binding thrombin and subsequently converting protein C to its active form (APC). In addition, the binding of thrombin to TM drastically alters the thrombin's procoagulant activities to anticoagulant activities. The lipid bilayer in which it resides serves as an essential 'cofactor', locally concentrating and coordinating the appropriate alignment of reacting cofactors and substrates for protein C activation. On the other hand, liposomes have been extensively studied as cell membrane model as well as carrier for delivering certain vaccines, …

Novel Solid State Properties Of Drugs, Polymers And Various Chemicals By Thermal And Analytical Techniques, Dhruthiman R. Mantheni

ETD Archive

I have observed unique variations in AC electrical conductivity of solids by dielectric analysis (DEA or DETA) when studied with respect to temperature and frequency. A wide range of solids were examined for this study e.g. organics, polymers, carbohydrates, API's (active pharmacy ingredients) and amino acids. Experimental results clearly show novel dielectric behavior of a linear increase in a log ionic conductivity vs. temperature in the pre-melt (20 to 30oC below the melt temperature) and melt transition regions. We have differentiated the solids which show the conductivity variations in pre-melt from those which do not e.g. pre-melt conductivity variations observed …

Development Of A ‘Clickable’ Non-Natural Nucleotide To Visualize The Replication Of Non-Instructional Dna Lesions, Edward A. Motea, Irene Lee, Anthony J. Berdis

Chemistry Faculty Publications

The misreplication of damaged DNA is an important biological process that produces numerous adverse effects on human health. This report describes the synthesis and characterization of a non-natural nucleotide, designated 3-ethynyl-5-nitroindolyl-2′-deoxyriboside triphosphate (3-Eth-5-NITP), as a novel chemical reagent that can probe and quantify the misreplication of damaged DNA. We demonstrate that this non-natural nucleotide is efficiently inserted opposite an abasic site, a commonly formed and potentially mutagenic non-instructional DNA lesion. The strategic placement of the ethynyl moiety allows the incorporated nucleoside triphosphate to be selectively tagged with an azide-containing fluorophore using ‘click’ chemistry. This reaction provides a facile way to …

Ua94/6/10 Student / Alumni Personal Papers Wku Carl Ellis, Wku Archives

WKU Archives Collection Inventories

Scientific notebooks used by Carl Ellis during his years at WKU.

Botppi, A New Wittig Salt Used In The Synthesis Of 12-(S)-Hydroxy-Eicosatetraenoic Acid [12-(S)-Hete], Michael A. Christiansen, Merritt B. Andrus

Chemistry and Biochemistry Faculty Publications

An efficient route to (Z)-(8-benzyloxy-8-oxooct-3-en-1-yl)triphenylphosphonium iodide, or BOTPPI, is disclosed, complete with full experimental details, NMR spectra, and HRMS data. BOTPPI serves as a surrogate for (Z)-(8-methoxy-8-oxooct-3-en-1-yl)triphenylphosphonium iodide, or MOTPPI, a Wittig salt previously used in two 12-HETE syntheses. BOTPPI has the advantage over MOTPPI of being derived from a sequence for which every intermediate is UV-active and amenable to large-scale chromatographic purification. A formal asymmetric total synthesis of 12-(S)-HETE is also reported, involving a stereoselective phase-transfer catalyzed (PTC) alkylation in its key step.

Ccl2 (Mcp-1) Mediates Chronic Pelvic Pain Through Mast Cells In Experimental Autoimmune Cystitis, Fuat Bicer

ETD Archive

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic inflammatory bladder condition with unknown pathophysiology. Chronic pelvic pain is one of the most important and disturbing symptoms of IC/PBS, beside urinary frequency, urgency, and nocturia. Increased amounts of mast cells (MCs) and CCL2 have been found in bladder tissue and urine, respectively. Whether or not there is a causal relationship between CCL2, MCs, and pelvic pain in IC/PBS is unknown. Methods: Female BALB/c mice were immunized with a peptide consisting of residues 65-84 of the bladder urothelium-specific protein uroplakin 3A to induce experimental autoimmune cystitis (EAC), a model for human IC/PBS. …

Chronic Kidney Disease: Vitamin D Treatment Regimens And Novel Assay Development For Kidney And Cardiovascular Function Biomarkers, Joe M. El-Khoury

ETD Archive

Chronic kidney disease (CKD) is highly prevalent in the US population and has high incidence of cardiovascular and all-cause mortality. A known complication of CKD is secondary hyperparathyroidism that is caused by bone and mineral imbalances, including vitamin D deficiency. Supplementation of CKD patients with vitamin D is based on guidelines issued by the Kidney Disease Quality Outcomes Initiative (K/DOQI), which recommend administration of vitamin D2 in variable doses depending on the severity of vitamin D deficiency. Retrospective and pilot studies have shown that vitamin D2 was not as effective as vitamin D3 in treating vitamin D deficiency. In Chapter …

Gain-Of-Function Mutations In Scn5a Gene Lead To Type-3 Long Qt Syndrome, Fang Fang

ETD Archive

Type-3 long QT syndrome, which is related to type 5 voltage-gated sodium channel alpha subunit (SCN5A) mutation, has been identified since 1995. LQTS mutation in SCN5A is a gain-of-function mutation producing late sodium current, INa,L. Brugada mutation in SCN5A is a loss-of-function causing INa decrease. Whereas, the mechanism for Dilated Cardiomyopathy mutations in SCN5A is still not fully understood. N1325S is one of the first series of mutations identified for type-3 LQTS. Our lab created a mouse model for LQTS by expressing SCN5A mutation N1325S in the mouse hearts (TG-NS) and a matched experimental control line with overexpression of wild- …

Development And Characterization Of Experimental Autoimmune Cystitis (Eac), Kenan Izgi

ETD Archive

Interstitial Cystitis/Painful Bladder Syndrome(IC/PBS) is a chronic inflammation of the urinary bladder, consisting of irritative voiding symptoms frequent and urgent urination and pain referred to the pelvic region or the bladder upon filling, lack of other pathology. The pathophysiology of interstitial cystitis (IC) is enigmatic. The impaired urothelium of bladder and autoimmunity might lead the underlying pathology. One of the shortcomings in IC/PBS research has been the lack of an appropriate animal model. In the current study, we show that the bladder specific Uroplakin 3A (UPK3A)-derived immunogenic UPK3A 65-84 peptide is capable of targeting experimental autoimmune cystitis (EAC) in BALB/c …

Ellagic Acid-Mediated Ck2 Inhibition;A Natural, Multifunctional Strategy To Trigger Cervical Cancer Cell Death In Vitro And In Vivo, Hanan F. Mohammad

ETD Archive

Targeting CK2 for cancer therapy has proven effective in inhibiting tumor growth in several histology's. The main goal of this study was to acquire pre-clinical data on a naturally occurring CK2-inhibitor (ellagic acid) in support of a human clinical trial. In vitro analysis included testing the spectrum of ellagic acid anti-cancer activity, defining the mode of growth inhibition in cancer cells and its impact on biochemical and molecular pathways. In vivo studies included determination of ellagic acid inhibitory effect in animal tumor models and toxicity analysis. We found that CK2 inhibition mediated by ellagic acid, was effective in inhibiting the …

Proteomic Approaches To Elucidate Molecular Mechanisms Of Metal Accumulation In Plants With Focus On Arsenic, Chamari Hasintha Walliwalagedara Kiribandage

ETD Archive

No abstract provided.

Rnase L Manipulates Macrophages In Innate Immunity And Tumor Growth, Xin Yi

ETD Archive

RNase L is one of the key enzymes in the 2-5A system of interferon (IFN) action against viral infection and cellular proliferation. Tissue distribution analysis has revealed that RNase L is highly expressed in the spleen, thymus, lung, testis, intestine and most of immune cells such as T, B cells and macrophages. However, the physiological role of RNase L in the immune system is largely unknown. My thesis thus focused on studying the possible physiological role of RNase L in macrophages. By using bone marrow-derived macrophages (BMMs) from RNase L+/+and -/- mice, we demonstrated that RNase L is involved in …

Purification And Characterization Of Blood Aspirin Hydrolases, Gang Zhou

ETD Archive

Aspirin prophylaxis suppresses major adverse cardiovascular events, but its turnover in blood is rapid, which limits its inhibitory effects on platelet cyclooxygenase and thrombosis. Inter-individual variability of platelet responses to aspirin clinically presents as treatment failure, and this increasing clinical phenomenon is frequently named aspirin "resistance". However, the molecular mechanisms behind this are unclear. Blood aspirin hydrolases are believed to control aspirin survival in vivo, but the identity of the circulating enzyme(s) that hydrolyzes aspirin remains unknown. In this thesis, blood aspirin hydrolases were identified and characterized. The relationship between blood aspirin hydrolases and aspirin efficacy was investigated. RP-HPLC analysis …

Boronic Acid Macroligands For Glycomics Applications, Poornima Pinnamaneni

ETD Archive

Cell surface carbohydrates existing as glycoproteins and glycolipids represent the first information about the cell with the outside world and are closely involved in various biological processes such as cell communication, and the molecular recognition and cell targeting. However, the mechanisms of most of the processes at the molecular level are still unclear. It is therefore very important to develop specific carbohydrate-binding molecules for a fast, efficient, sensitive and accurate analysis of complex carbohydrates structures and functions, known as glycomics. In addition, certain carbohydrate-binding molecules can be used in medical applications such as biomarkers for diseases diagnosis and targeted drug …