Simulation Evidence Of Hexagonal-To-Tetragonal Znse Structure Transition: A Monolayer Material With A Wide-Range Tunable Direct Bandgap, 2015 University of Nebraska-Lincoln
Simulation Evidence Of Hexagonal-To-Tetragonal Znse Structure Transition: A Monolayer Material With A Wide-Range Tunable Direct Bandgap, Lei Li, Pengfei Li, Ning Lu, Jun Dai, Xiao Cheng Zeng
Chemistry Department: Faculty Publications
2D material with tunable direct bandgap in the intermediate region (i.e., ≈2–3 eV) is key to the achievement of high efficiency in visible-light optical devices. Herein, a simulation evidence of structure transition of monolayer ZnSe from the experimental pseudohexagonal structure to the tetragonal structure (t-ZnSe) under lateral pressure is shown, suggesting a possible fabrication route to achieve the t-ZnSe monolayer. The as-produced t-ZnSe monolayer exhibits highly tunable bandgap under the biaxial strains, allowing strain engineering of t-ZnSe’s bandgap over a wide range of 2–3 eV. Importantly, even under the biaxial strain up to 7%, the t-ZnSe monolayer still keeps its …
Curcumin: A Folklore Remedy From Kitchen On The Way To Clinic As Cancer Drug, 2015 The University of Texas Rio Grande Valley
Curcumin: A Folklore Remedy From Kitchen On The Way To Clinic As Cancer Drug, Debasish Bandyopadhyay
Chemistry Faculty Publications and Presentations
Numerous compounds are widely distributed in nature and many of these possess medicinal/biological/pharmacological activity. Curcumin, a polyphenol derived from the rhizomes (underground stems) of Curcuma longa Linn (a member of the ginger family, commonly known as turmeric) is a culinary spice and therapeutic used in India for thousands of years to induce color and flavor in food as well as to treat a wide array of diseases. The origin of turmeric as spice and folklore medicine is so old that it is lost in legend. Curcumin has many beneficial pharmacological effects which includes, but are not limited with, antimicrobial, anti-inflammatory, …
Photogenerated O-Azaxylylenes: Mechanistic Studies And Synthetic Applications, 2015 University of Denver
Photogenerated O-Azaxylylenes: Mechanistic Studies And Synthetic Applications, William Cole Cronk
Electronic Theses and Dissertations
This research sets out to build upon excited state o-azaxylylene cycloaddition. The mechanism behind the excitation and cycloaddition process of photogenerated o-azaxylylenes was determined experimentally. Time-correlated single-photon counting, steady-state spectroscopy, triplet quenching experiments, and quantum yield studies provided evidence suggesting that excited state intramolecular proton transfer is followed by intersystem crossing and stepwise addition to the tethered unsaturated pendant.
In keeping with the principles of diversity oriented synthesis, a modular approach was taken to gain access to a diverse array of N,O,S-Polyheterocycles which were modified postphotochemically via Suzuki coupling to yield fused biaryls. Cycloaddition products, outfitted with halogens …
New Methods For Measuring Transient Interactions Between Proteins And Curved Membranes, 2015 University of Denver
New Methods For Measuring Transient Interactions Between Proteins And Curved Membranes, Philip P. Cheney
Electronic Theses and Dissertations
Variations in the physical deformation of the plasma membrane play a significant role in the sorting and behavior of the proteins that occupy it. Determining the interplay between membrane curvature and protein behavior required the development and thorough characterization of a model plasma membrane with well defined and localized regions of curvature. This model system consists of a fluid lipid bilayer that is supported by a dye-loaded polystyrene nanoparticle patterned glass substrate. As the physical deformation of the supported lipid bilayer is essential to our understanding of the behavior of the protein occupying the bilayer, extensive characterization of the structure …
Fluorescent Biological Aerosol Particles In Coastal Canada And The Link To Atmospheric Ice Nuclei, 2015 University of Denver
Fluorescent Biological Aerosol Particles In Coastal Canada And The Link To Atmospheric Ice Nuclei, Jixiao Li
Electronic Theses and Dissertations
Bioaerosols are a subgroup of atmospheric aerosols and are often linked to the spread of human, animal and plant diseases. Bioaerosols also may play an indirect effect on environmental processes, including the formation of precipitation and alteration of the global climate through their role as nuclei for cloud droplet formation. Several types of biological organisms (e.g., fungi and bacteria) have been shown to be effective ice nuclei (IN) and cloud condensation nuclei (CCN).
During 21 days in August 2013 we participated in a collaborative international campaign at a rural, coastal site near the village of Ucluelet on the west coast …
Rapid Scan Electron Paramagnetic Resonance (Epr) And Digital Epr Development, 2015 University of Denver
Rapid Scan Electron Paramagnetic Resonance (Epr) And Digital Epr Development, Zhelin Yu
Electronic Theses and Dissertations
Rapid scan electron paramagnetic resonance (EPR) was developed in the Eaton laboratory at the University of Denver. Applications of rapid scan to wider spectra, such as for immobilized nitroxides, spin-labeled proteins, irradiated tooth and fingernail samples were demonstrated in this dissertation. The scan width has been increased from 55 G to 160 G. The signal to noise (S/N) improvement for slowly tumbling spin-labeled protein samples that is provided by rapid scan EPR will be highly advantageous for biophysical studies. With substantial improvement in S/N by rapid scan, the dose estimation for irradiated tooth enamels became more reliable than …
Measurement Of Particulate Transition Metals And Atmospheric Processing Of Iron, 2015 University of Denver
Measurement Of Particulate Transition Metals And Atmospheric Processing Of Iron, Benton T. Cartledge
Electronic Theses and Dissertations
The work presented herein details the measurement of particle-bound metals in environmental samples with specific interests in iron (Fe) in atmospheric particulate matter. Metals were measured in ambient PM2.5 to study the effects and contributions of a light rail system on the concentrations of metals in atmospheric particles. Particulate matter samples were collected on board trains, near the tracks, and at an urban background location in Denver, CO. Metals were found to be enriched in particles collected on board the trains more so than at the other locations. Fe speciation was also measured in the soluble fraction of the …
Cellulose, Chitosan, And Keratin Composite Materials. Controlled Drug Release, 2015 Marquette University
Cellulose, Chitosan, And Keratin Composite Materials. Controlled Drug Release, Chieu D. Tran, Tamutsiwa Moven Mututuvari
Chemistry Faculty Research and Publications
A method was developed in which cellulose (CEL) and/or chitosan (CS) were added to keratin (KER) to enable [CEL/CS+KER] composites to have better mechanical strength and wider utilization. Butylmethylimmidazolium chloride ([BMIm+Cl–]), an ionic liquid, was used as the sole solvent, and because the [BMIm+Cl–] used was recovered, the method is green and recyclable. Fourier transform infrared spectroscopy results confirm that KER, CS, and CEL remain chemically intact in the composites. Tensile strength results expectedly show that adding CEL or CS into KER substantially increases the mechanical strength of the composites. We found …
Synthetic Studies Of Ambruticin: Preparation Of The C1-C8 Tetrahydropyran And The C17-C24 Dihydropyran Segments, 2015 Marquette University
Synthetic Studies Of Ambruticin: Preparation Of The C1-C8 Tetrahydropyran And The C17-C24 Dihydropyran Segments, Luping Liu, Julie L. Wondergem, William A. Donaldson
Chemistry Faculty Research and Publications
The C1-C8 tetrahydropyran and the C17-C24 dihdropyran segments of ambruticin were prepared from L-arabinose in 11 steps, 7.6% overall yield and from (S)-ethyl lactate in 8 steps, 22.2% overall yield respectively.
Electrostatic Point Charge Fitting As An Inverse Problem: Revealing The Underlying Ill-Conditioning, 2015 Marquette University
Electrostatic Point Charge Fitting As An Inverse Problem: Revealing The Underlying Ill-Conditioning, Maxim Vadimovich Ivanov, Marat R. Talipov, Qadir K. Timerghazin
Chemistry Faculty Research and Publications
Atom-centered point charge (PC) model of the molecular electrostatics-a major workhorse of the atomistic biomolecular simulations-is usually parameterized by least-squares (LS) fitting of the point charge values to a reference electrostatic potential, a procedure that suffers from numerical instabilities due to the ill-conditioned nature of the LS problem. To reveal the origins of this ill-conditioning, we start with a general treatment of the point charge fitting problem as an inverse problem and construct an analytical model with the point charges spherically arranged according to Lebedev quadrature which is naturally suited for the inverse electrostatic problem. This analytical model is contrasted …
Bimetallic Complexes Supported By A Redox-Active Ligand With Fused Pincer-Type Coordination Sites, 2015 Marquette University
Bimetallic Complexes Supported By A Redox-Active Ligand With Fused Pincer-Type Coordination Sites, Denan Wang, Sergey Lindeman, Adam T. Fiedler
Chemistry Faculty Research and Publications
The remarkable chemistry of mononuclear complexes featuring tridentate, meridionally chelating “pincer” ligands has stimulated the development of ligand frameworks containing multiple pincer sites. Here, the coordination chemistry of a novel pentadentate ligand (LN3O2) that provides two closely spaced NNO pincer-type compartments fused together at a central diarylamido unit is described. The trianionic LN3O2 chelate supports homobimetallic structures in which each M(II) ion (M = Co, Cu, Zn) is bound in a meridional fashion by the bridging diarylamido N atom and O,N-donors of the salicyaldimine arms. The metal centers are also coordinated by a mono- or bidentate …
Chemoselective Formation Of Unsymmetrically Substituted Ethers From Catalytic Reductive Coupling Of Aldehydes And Ketones With Alcohols In Aqueous Solution, 2015 Marquette University
Chemoselective Formation Of Unsymmetrically Substituted Ethers From Catalytic Reductive Coupling Of Aldehydes And Ketones With Alcohols In Aqueous Solution, Nishantha Kumara Kalutharage, Chae S. Yi
Chemistry Faculty Research and Publications
A well-defined cationic Ru–H complex catalyzes reductive etherification of aldehydes and ketones with alcohols. The catalytic method employs environmentally benign water as the solvent and cheaply available molecular hydrogen as the reducing agent to afford unsymmetrical ethers in a highly chemoselective manner.
Genetic Algorithm Optimization Of Point Charges In Force Field Development: Challenges And Insights, 2015 Marquette University
Genetic Algorithm Optimization Of Point Charges In Force Field Development: Challenges And Insights, Maxim Vadimovich Ivanov, Marat R. Talipov, Qadir K. Timerghazin
Chemistry Faculty Research and Publications
Evolutionary methods, such as genetic algorithms (GAs), provide powerful tools for optimization of the force field parameters, especially in the case of simultaneous fitting of the force field terms against extensive reference data. However, GA fitting of the nonbonded interaction parameters that includes point charges has not been explored in the literature, likely due to numerous difficulties with even a simpler problem of the least-squares fitting of the atomic point charges against a reference molecular electrostatic potential (MEP), which often demonstrates an unusually high variation of the fitted charges on buried atoms. Here, we examine the performance of the GA …
A Cu4S Model For The Nitrous Oxide Reductase Active Sites Supported Only By Nitrogen Ligands, 2015 University of Illinois at Chicago
A Cu4S Model For The Nitrous Oxide Reductase Active Sites Supported Only By Nitrogen Ligands, Brittany J. Johnson, William E. Antholine, Sergey V. Lindeman, Neal P. Mankad
Chemistry Faculty Research and Publications
To model the (His)7Cu4Sn (n = 1 or 2) active sites of nitrous oxide reductase, the first Cu4(μ4-S) cluster supported only by nitrogen donors has been prepared using amidinate supporting ligands. Structural, magnetic, spectroscopic, and computational characterization is reported. Electrochemical data indicates that the 2-hole model complex can be reduced reversibly to the 1-hole state and irreversibly to the fully reduced state.
Structural Classification Of Metal Complexes With Three-Coordinate Centres, 2015 Winston-Salem State University
Structural Classification Of Metal Complexes With Three-Coordinate Centres, Timothy L. Davis, Joshua A. Watts, Kenneth J. Brown, Jeewantha S. Hewage, Alexander Richard Treleven, Sergey V. Lindeman, James R. Gardinier
Chemistry Faculty Research and Publications
Attempts to describe the geometry about three-coordinate silver(I) complexes have proven difficult because interatomic angles generally vary wildly and there is no adequate or readily available classification system found in the literature. A search of the Cambridge Structural Database shows that complexes formed between any metal centre and three non-metal donors (18001 examples) usually adopt geometries that are quite different than ideal ‘textbook’ extremes of either trigonal planar (∼4% with α = β = γ = 120 ± 2°), T-shaped (∼0.05% with α = 180 ± 2°, β = γ = 90 ± 2°), or trigonal pyramidal (∼0.3% with α …
Development Of A Three Step Cascade Synthesis Of 2,4-Dihydro-1h-Benzo[F]Isochromenes, 2015 College of William & Mary - Arts & Sciences
Development Of A Three Step Cascade Synthesis Of 2,4-Dihydro-1h-Benzo[F]Isochromenes, Shane E. Lewis
Dissertations, Theses, and Masters Projects
No abstract provided.
Development Of A Solid-Supported Glaser-Hay Reaction And Utilization In Conjunction With Unnatural Amino Acids, 2015 College of William & Mary - Arts & Sciences
Development Of A Solid-Supported Glaser-Hay Reaction And Utilization In Conjunction With Unnatural Amino Acids, Jessica S. Lampkowski
Dissertations, Theses, and Masters Projects
No abstract provided.
Specific N-Glycans Of Hepatocellular Carcinoma Cell Surface And The Abnormal Increase Of Core-Α-1, 6-Fucosylated Triantennary Glycan Via N-Acetylglucosaminyltransferases-Iva Regulation, 2015 Harbin Institute of Technology
Specific N-Glycans Of Hepatocellular Carcinoma Cell Surface And The Abnormal Increase Of Core-Α-1, 6-Fucosylated Triantennary Glycan Via N-Acetylglucosaminyltransferases-Iva Regulation, Huan Nie, Xia Liu, Yubao Zhang, Tingting Li, Chao Zhan, Wenjuan Huo, Anshun He, Yuanfei Yao, Yu Jin, Youpeng Qu, Xue-Long Sun, Yu Li
Chemistry Faculty Publications
Glycosylation alterations of cell surface proteins are often observed during the progression of malignancies. The specific cell surface N-glycans were profiled in hepatocellular carcinoma (HCC) with clinical tissues (88 tumor and adjacent normal tissues) and the corresponding serum samples of HCC patients. The level of core-α-1,6-fucosylated triantennary glycan (NA3Fb) increased both on the cell surface and in the serum samples of HCC patients (p < 0.01). Additionally, the change of NA3Fb was not influenced by Hepatitis B virus (HBV)and cirrhosis. Furthermore, the mRNA and protein expression of N-acetylglucosaminyltransferase IVa (GnT-IVa), which was related to the synthesis of the NA3Fb, was substantially increased in HCC tissues. Knockdown of GnT-IVa leads to a decreased level of NA3Fb and decreased ability of invasion and migration in HCC cells. NA3Fb can be regarded as a specific cell surface N-glycan of HCC. The high expression of GnT-IVa is the cause of the abnormal increase of NA3Fb on the HCC cell surface, which regulates cell migration. This study demonstrated the specific N-glycans of the cell surface and the mechanisms of altered glycoform related with HCC. These findings lead to better understanding of the function of glycan and glycosyltransferase in the tumorigenesis, progression and metastasis of HCC.
Quartz Crystal Microbalance Studies On Friction Modifiers For Lubricant Applications, 2015 Virginia Commonwealth University
Quartz Crystal Microbalance Studies On Friction Modifiers For Lubricant Applications, Carey Lehner
Theses and Dissertations
Lubricants are used in numerous applications to control friction and protect moving parts from fatigue. These fluids consist of a variety of surface active chemistries competing for the surface to provide performance. In order to develop fluids that meet the ever-increasing requirements (from legislation and manufacturers), techniques that can provide insight into surface adsorption, in real time, and relate it back to performance are critical.
The objective of this work is to determine if Quartz Crystal Microbalance with Dissipation (QCM-D) is an effective technique to investigate surfactant adsorption in regimes that are common to the transportation lubricant industry. QCM-D is …
Analytical Method Development For The Detection And Analysis Of Protein Carbonyls, 2015 Virginia Commonwealth University
Analytical Method Development For The Detection And Analysis Of Protein Carbonyls, Chelsea M. Coffey
Theses and Dissertations
Oxidative stress can result in changes to many biomolecules and also affect their activities. We are interested in protein carbonylation, a type of unnatural oxidation which has been associated with numerous degenerative disease states and is also a consequence of the natural aging process. Protein carbonyls are stable species, but countless analytical barriers exist in terms of their identification. Thus, the main goal of this work was to develop and optimize analytical methods that could be used to help us better understand which, where, and how proteins are being carbonylated.
Initial studies involved method validation for carbonylating, tagging, and enriching …