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2016

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Articles 451 - 480 of 1435

Full-Text Articles in Chemistry

Nx∙∙Y Halogen Bonds. Comparison With Nh∙∙Y H-Bonds And Cx∙∙Y Halogen Bonds, Binod Nepal, Steve Scheiner Jun 2016

Nx∙∙Y Halogen Bonds. Comparison With Nh∙∙Y H-Bonds And Cx∙∙Y Halogen Bonds, Binod Nepal, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Quantum calculations examine how the NH∙∙Y H-bond compares to the equivalent NX∙∙Y halogen bond, as well as to comparable CH/CX donors. Succinimide and saccharin, and their corresponding halogen-substituted derivatives, are chosen as the prototype NH/NX donors, paired with a wide range of electron donor molecules. The NH∙∙Y H-bond is weakened if the bridging H is replaced by Cl, and strengthened by I; a Br halogen bond is roughly comparable to a H-bond. The lone pairs of the partner molecule are stronger electron donors than are π-systems. Whereas Coulombic forces represent the largest fraction of the attractive force in the H-bonds, …

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Enzyme-Mediated And Mechanistic Investigations Of Tetrahydroisoquinoline Synthesis Through The Pictet-Spengler Reaction, Jordan Elise Fauser Jun 2016

Enzyme-Mediated And Mechanistic Investigations Of Tetrahydroisoquinoline Synthesis Through The Pictet-Spengler Reaction, Jordan Elise Fauser

College of Science and Health Theses and Dissertations

Tetrahydroisoquinolines (THI) are biologically active natural products with applications to a variety of diseases. These compounds also act as precursors for other pharmacologically active natural products. In this investigation, a new synthetic approach for generation of halogenated THIs was proposed. Using cross-linked tyrosinase aggregate, halogenated tyrosine and tyramine were oxidized to form halogenated catechols such as halogenated L-DOPA and dopamine. In a one-pot synthetic approach, the enzyme oxidation reaction was coupled to the Pictet-Spengler reaction, through the addition of an aldehyde, to generate halogenated THIs. The Pictet-Spengler reaction was catalyzed by the phosphate buffer in the reaction solution. The role …

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Biomimetic Tools In Oxidative Metabolism: Characterization Of Reactive Metabolites From Antithyroid Drugs, Kudzanai Chipiso Jun 2016

Biomimetic Tools In Oxidative Metabolism: Characterization Of Reactive Metabolites From Antithyroid Drugs, Kudzanai Chipiso

Dissertations and Theses

Toxicities of sulfur-based drugs have been attributed to formation of highly reactive sulfur oxo-acids and depletion of glutathione by the formation of reactive metabolites. Metabolic activation of these sulfur centers to conceivably toxic reactive metabolites (RMs) that can covalently modify proteins is considered the initial step in drug-induced toxicity. Despite considerable effort and research, detection and characterization of these RMs during drug development and therapy remains a challenge. Methimazole (MMI) and 6-propyl-2-thiouracil (PTU) are two commonly used antithyroid, sulfur-based drugs. Though effective, these drugs are associated with idiosyncratic toxicity. PTU has acquired a black box warning and physicians are calling …

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Chemically Accurate Simulation Of A Polyatomic Molecule-Metal Surface Reaction, Francesco Nattino, Davide Migliorini, Geert-Jan Kroes, Eric Dombrowski, Eric A. High High, Daniel Killelea, Arthur Utz Jun 2016

Chemically Accurate Simulation Of A Polyatomic Molecule-Metal Surface Reaction, Francesco Nattino, Davide Migliorini, Geert-Jan Kroes, Eric Dombrowski, Eric A. High High, Daniel Killelea, Arthur Utz

Chemistry: Faculty Publications and Other Works

Although important to heterogeneous catalysis, the ability to accurately model reactions of polyatomic molecules with metal surfaces has not kept pace with developments in gas phase dynamics. Partnering the specific reaction parameter (SRP) approach to density functional theory with ab initio molecular dynamics (AIMD) extends our ability to model reactions with metals with quantitative accuracy from only the lightest reactant, H2, to essentially all molecules. This is demonstrated with AIMD calculations on CHD3 + Ni(111) in which the SRP functional is fitted to supersonic beam experiments, and validated by showing that AIMD with the resulting functional reproduces initial-state selected sticking …

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First Order Time Evolution, Ronald Lovett Jun 2016

First Order Time Evolution, Ronald Lovett

Topics in Quantum Mechanics

No abstract provided.

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Rotamer-Restricted Fluorogenicity Of The Bis-Arsenical Reash, A. S. Walker, Paul R. Rablen, A. Schepartz Jun 2016

Rotamer-Restricted Fluorogenicity Of The Bis-Arsenical Reash, A. S. Walker, Paul R. Rablen, A. Schepartz

Chemistry & Biochemistry Faculty Works

Fluorogenic dyes such as FlAsH and ReAsH are used widely to localize, monitor, and characterize proteins and their assemblies in live cells. These bis-arsenical dyes can become fluorescent when bound to a protein containing four proximal Cys thiols—a tetracysteine (Cys4) motif. Yet the mechanism by which bis-arsenicals become fluorescent upon binding a Cys4 motif is unknown, and this nescience limits more widespread application of this tool. Here we probe the origins of ReAsH fluorogenicity using both computation and experiment. Our results support a model in which ReAsH fluorescence depends on the relative orientation of the aryl chromophore and the appended …

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Effect Of Polymer Concentration Rotational Speed And Solvent Mixture On Fiber Formation Using Forcespinning®, Nancy Obregon, Victor Agubra, Madhab Pokhrel, Howard Campos, David Flores, David De La Garza, Yuanbing Mao, Javier Macossay-Torres, Mataz Alcoutlabi Jun 2016

Effect Of Polymer Concentration Rotational Speed And Solvent Mixture On Fiber Formation Using Forcespinning®, Nancy Obregon, Victor Agubra, Madhab Pokhrel, Howard Campos, David Flores, David De La Garza, Yuanbing Mao, Javier Macossay-Torres, Mataz Alcoutlabi

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Polycaprolactone (PCL) fibers were produced using Forcespinning® (FS). The effects of PCL concentration, solvent mixture, and the spinneret rotational speed on fiber formation were evaluated. The concentration of the polymer in the solvents was a critical determinant of the solution viscosity. Lower PCL concentrations resulted in low solution viscosities with a correspondingly low fiber production rate with many beads. Bead-free fibers with high production rate and uniform fiber diameter distribution were obtained from the optimum PCL concentration (i.e., 12.5 wt%) with tetrahydrofuran (THF) as the solvent. The addition of N, N-dimethylformamide (DMF) to the THF solvent promoted the gradual formation …

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Atomistic Corrective Scheme For Supercell Density Functional Theory Calculations Of Charged Defects, Tengfei Cao, Angelo Bongiorno Jun 2016

Atomistic Corrective Scheme For Supercell Density Functional Theory Calculations Of Charged Defects, Tengfei Cao, Angelo Bongiorno

Publications and Research

A new method to correct formation energies of charged defects obtained by supercell densityfunctional calculations is presented and applied to bulk, surface, and low-dimensional systems. The method relies on atomistic models and a polarizable force field to describe a material system and its dielectric properties. The polarizable force field is based on a minimal set of fitting parameters, it accounts for the dielectric screening arising from ions and electrons separately, and it can be easily implemented in any software for atomistic molecular dynamics simulations. This work illustrates both technical aspects and applications of the new corrective scheme. The method is …

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Thermally Selective Formation Of Subsurface Oxygen In Ag(111) And Consequent Surface Structure, Jonathan Derouin, Rachael G. Farber, Marie E. Turano, Erin V. Iski, Daniel Killelea Jun 2016

Thermally Selective Formation Of Subsurface Oxygen In Ag(111) And Consequent Surface Structure, Jonathan Derouin, Rachael G. Farber, Marie E. Turano, Erin V. Iski, Daniel Killelea

Chemistry: Faculty Publications and Other Works

A long-standing challenge in the study of heterogeneously catalyzed reactions on silver surfaces has been the determination of what oxygen species are of greatest chemical importance. This is due to the coexistence of several different surface phases on oxidized silver surfaces. A further complication is subsurface oxygen (Osub). Osub are O atoms absorbed into the near surface of a metal, and are expected to alter the surface in terms of chemistry and structure, but these effects have yet to be well characterized. We studied oxidized Ag(111) surfaces after exposure to gas-phase O atoms to determine how Osub is formed and …

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Biological Information And Its Origins: The Curious Case Of Rna, Grace E. Andrews Jun 2016

Biological Information And Its Origins: The Curious Case Of Rna, Grace E. Andrews

Honors Projects

Information is an important pre-requisite for the onset of life, which means that any study of the origins of life must also address the origin of information. Biological information today is generally conceptualized in terms of the Central Dogma of Biology, with DNA as a digitized code within the cell. However, here I propose that biological information - particularly in prebiotic conditions, where information would have first arisen - is better understood in terms of the three-dimensional structure of a molecule. Evidence for information storage in RNA can be seen in a number of ways. One of these is that, …

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Photooxidation Chemistry And Photodynamic Therapy: Pointsource Delivery Of Singlet Oxygen, Sensitizer And Nitrosamine Drugs, Ashwini Anil Ghogare Jun 2016

Photooxidation Chemistry And Photodynamic Therapy: Pointsource Delivery Of Singlet Oxygen, Sensitizer And Nitrosamine Drugs, Ashwini Anil Ghogare

Dissertations, Theses, and Capstone Projects

Eradication of residual tumor cells that are directly adjacent to vital tissue is a daunting challenge to surgeons. Because the field needs advances in intraoperative settings and a means for high-precision delivery of singlet oxygen for photodynamic therapy (PDT) of cancers, this dissertation outlines the development and application of a “pointsource” fiber optic device. The device offers highly localized and simultaneous delivery of sensitizer drug, light, and oxygen (components necessary for PDT) for cancer cell eradication in-vitro and in-vivo. The following chapters describe (a) the photokilling activity and precision of pointsource PDT in monolayer ovarian and brain cancer cells …

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Interaction Of Spliceosomal U2 Snrnp Protein P14 With Its Branch Site Rna Target, William Perea Vargas Jun 2016

Interaction Of Spliceosomal U2 Snrnp Protein P14 With Its Branch Site Rna Target, William Perea Vargas

Dissertations, Theses, and Capstone Projects

Newly transcribed precursor messenger RNA (pre-mRNA) molecules contain coding sequences (exons) interspersed with non-coding intervening sequences (introns). These introns must be removed in order to generate a continuous coding sequence prior to translation of the message into protein. The mechanism through which these introns are removed is known as pre-mRNA splicing, a two-step reaction catalyzed be a large macromolecular machine, the spliceosome, located in the nucleus of eukaryotic cells. The spliceosome is a protein-directed ribozyme composed of small nuclear RNAs (snRNA) and hundreds of proteins that assemble in a very dynamic process. One of these snRNAs, the U2 snRNA, is …

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Aqueous Photochemistry Of Glyoxylic Acid, Alexis J. Eugene, Sha-Sha Xia, Marcelo I. Guzman Jun 2016

Aqueous Photochemistry Of Glyoxylic Acid, Alexis J. Eugene, Sha-Sha Xia, Marcelo I. Guzman

Chemistry Faculty Publications

Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging …

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Development And Implementation Of Problem-Based Chemistry Experiments For Engineering Students In A Multi-Disciplinary Course, Tiffany Hesser, Stephanie R. Bunyea Jun 2016

Development And Implementation Of Problem-Based Chemistry Experiments For Engineering Students In A Multi-Disciplinary Course, Tiffany Hesser, Stephanie R. Bunyea

Chemistry and Chemical Engineering Faculty Publications

This paper will describe the implementation and continuing development of five problem based laboratory experiments in a general chemistry course designed specifically for multiple disciplines of engineering students at the University of New Haven. The Problem Based Laboratory Experiments (PBLE) were developed to provide students with the opportunity to perform and develop experimental procedures working in interdisciplinary teams, while achieving a greater understanding of the role of chemistry in engineering fields. In each PBLE, students first complete a traditional chemistry experiment to gain an understanding of the chemical concepts and to become familiar with executing a written procedure with a …

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Oncogenic Pik3ca Mutations Reprogram Glutamine Metabolism In Colorectal Cancer, Yujun Hao, Yardena Samuels, Qingling Li, Dawid Krokowski, Bo-Jhih Guan, Chao Wang, Zhicheng Jin, Bohan Dong, Bo Cao, Xiujing Feng, Min Xiang, Claire Xu, Stephen Fink, Neal J. Meropol, Yan Xu Jun 2016

Oncogenic Pik3ca Mutations Reprogram Glutamine Metabolism In Colorectal Cancer, Yujun Hao, Yardena Samuels, Qingling Li, Dawid Krokowski, Bo-Jhih Guan, Chao Wang, Zhicheng Jin, Bohan Dong, Bo Cao, Xiujing Feng, Min Xiang, Claire Xu, Stephen Fink, Neal J. Meropol, Yan Xu

Chemistry Faculty Publications

Cancer cells often require glutamine for growth, thereby distinguishing them from most normal cells. Here we show that PIK3CA mutations reprogram glutamine metabolism by upregulating glutamate pyruvate transaminase 2 (GPT2) in colorectal cancer (CRC) cells, making them more dependent on glutamine. Compared with isogenic wild-type (WT) cells, PIK3CA mutant CRCs convert substantially more glutamine to alpha-ketoglutarate to replenish the tricarboxylic acid cycle and generate ATP. Mutant p110 alpha upregulates GPT2 gene expression through an AKT-independent, PDK1-RSK2-ATF4 signalling axis. Moreover, aminooxyacetate, which inhibits the enzymatic activity of aminotransferases including GPT2, suppresses xenograft tumour growth of CRCs with PIK3CA mutations, but not …

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Identification Of A Disulfide Bridge In Sodium-Coupled Neutral Amino Acid Transporter 2(Snat2) By Chemical Modification, Chen Chen, Jiahong Wang, Ruiping Cai, Yanmen M. Yuan, Zhanyun Y. Guo, Christof Grewer, Zhou Zhang Jun 2016

Identification Of A Disulfide Bridge In Sodium-Coupled Neutral Amino Acid Transporter 2(Snat2) By Chemical Modification, Chen Chen, Jiahong Wang, Ruiping Cai, Yanmen M. Yuan, Zhanyun Y. Guo, Christof Grewer, Zhou Zhang

Chemistry Faculty Scholarship

Sodium-coupled neutral amino acid transporter 2 (SNAT2) belongs to solute carrier 38 (SLC38) family of transporters, which is ubiquitously expressed in mammalian tissues and mediates transport of small, neutral amino acids, exemplified by alanine(Ala, A). Yet structural data on SNAT2, including the relevance of intrinsic cysteine residues on structure and function, is scarce, in spite of its essential roles in many tissues. To better define the potential of intrinsic cysteines to form disulfide bonds in SNAT2, mutagenesis experiments and thiol-specific chemical modifications by N-ethylmaleimide (NEM) and methoxy-polyethylene glycol maleimide (mPEG-Mal, MW 5000) were performed, with or without the reducing regent …

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Controlling Activity And Selectivity Using Water In The Au-Catalysed Preferential Oxidation Of Co In H2, Johnny Saavedra, Todd N. Whittaker, Z. Chen, Christopher J. Pursell, R. M. Rioux, Bert D. Chandler Jun 2016

Controlling Activity And Selectivity Using Water In The Au-Catalysed Preferential Oxidation Of Co In H2, Johnny Saavedra, Todd N. Whittaker, Z. Chen, Christopher J. Pursell, R. M. Rioux, Bert D. Chandler

Chemistry Faculty Research

Industrial hydrogen production through methane steam reforming exceeds 50 million tons annually and accounts for 2–5% of global energy consumption. The hydrogen product, even after processing by the water–gas shift, still typically contains ∼1% CO, which must be removed for many applications. Methanation (CO + 3H2 → CH4 + H2O) is an effective solution to this problem, but consumes 5–15% of the generated hydrogen. The preferential oxidation (PROX) of CO with O2 in hydrogen represents a more-efficient solution. Supported gold nanoparticles, with their high CO-oxidation activity and notoriously low hydrogenation activity, have long been examined …

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Nitrogenase Bioelectrocatalysis: Heterogeneous Ammonia And Hydrogen Production By Mofe Protein, Ross D. Milton, Sofiene Abdellaoui, Nimesh Khadka, Dennis R. Dean, Donal Leech, Lance C. Seefeldt, Shelley D. Minteer Jun 2016

Nitrogenase Bioelectrocatalysis: Heterogeneous Ammonia And Hydrogen Production By Mofe Protein, Ross D. Milton, Sofiene Abdellaoui, Nimesh Khadka, Dennis R. Dean, Donal Leech, Lance C. Seefeldt, Shelley D. Minteer

Chemistry and Biochemistry Faculty Publications

notrogenase is the only enzyme known to catalyze the reduction of N2 to 2NH3. In vivo, the MoFe protein component of nitrogenase is exclusively reduced by the ATP-hydrolyzing Fe protein in a series of transient association/dissociation steps that are linked to the hyderolysis of two ATP for each electron transeferred. We report MoFe protein immobilized at an electrode surface, where cobaltocene (as an electron mediator that can be observed in real time at a carbon electrode) is used to reduce the MoFe protein (independent of the Fe protein and of ATP hydrolysis) and support the bioelectrocatalytic reduction of protons to …

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A New Set Of Potential Energy Surfaces For Hco: Influence Of Renner-Teller Coupling On The Bound And Resonance Vibrational States, Steve Alexandre Ndengué, Richard Dawes, Hua Guo Jun 2016

A New Set Of Potential Energy Surfaces For Hco: Influence Of Renner-Teller Coupling On The Bound And Resonance Vibrational States, Steve Alexandre Ndengué, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

It is commonly understood that the Renner-Teller effect can strongly influence the spectroscopy of molecules through coupling of electronic states. Here we investigate the vibrational bound states and low-lying resonances of the formyl radical treating the Renner-Teller coupled X2A' and Ã2A" states using the MultiConfiguration Time Dependent Hartree (MCTDH) method. The calculations were performed using the improved relaxation method for the bound states and a recently published extension to compute resonances. A new set of accurate global potential energy surfaces were computed at the explicitly correlated multireference configuration interaction (MRCI-F12) level and yielded remarkably close agreement with experiment in this …

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The C-H Stretching Features At 3.2-3.5 Μm Of Polycyclic Aromatic Hydrocarbons With Aliphatic Sidegroups, Xuejuan Yang, Aigen Li, Rainer Glaser, Jianxin Zhong Jun 2016

The C-H Stretching Features At 3.2-3.5 Μm Of Polycyclic Aromatic Hydrocarbons With Aliphatic Sidegroups, Xuejuan Yang, Aigen Li, Rainer Glaser, Jianxin Zhong

Chemistry Faculty Research & Creative Works

The so-called "unidentified" infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm are ubiquitously seen in a wide variety of astrophysical regions. The UIE features are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, e.g., polycyclic aromatic hydrocarbon (PAH) molecules. The 3.3 μm aromatic C-H stretching feature is often accompanied by a weaker feature at 3.4 μm. The latter is generally thought to result from the C-H stretch of aliphatic groups attached to the aromatic systems. The ratio of the observed intensity of the 3.3 μm aromatic C-H feature to that of the 3.4 …

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N-Terminal Domains Of Copper Atpases In Plasmodium Falciparum, Dictyostelium Dicsoideum, Human Atp7b And A Chimera Of Atox1 With Metal Binding Domain Four Of Atp7b, Javan Kilango Kisaka Jun 2016

N-Terminal Domains Of Copper Atpases In Plasmodium Falciparum, Dictyostelium Dicsoideum, Human Atp7b And A Chimera Of Atox1 With Metal Binding Domain Four Of Atp7b, Javan Kilango Kisaka

Dissertations

Copper transporting ATPases (Cu-ATPases) are essential for mediating copper uptake, maintaining cellular copper levels and prevention of accumulation of toxic copper. The most studied copper ATPases are the Menkes and Wilson proteins in eukaryotes, CopA and CopB found in bacteria. The precise interaction of the metal binding domains with their copper donor, the association of each metal binding domain within the N-terminal portion of the protein, how they communicate with each other, and the eventual metal ion translocation across the membrane, is little known. The variation in number of the cytosolic metal binding domains may also offer clues on the …

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Novel Protein Disulfide Isomerase Inhibitor With Anticancer Activity In Multiple Myeloma, Sergei Vatolin, James G. Phillips, Babal K. Jha, Shravya Govindgari, Jennifer Hu, Dale Grabowski, Yvonne Parker, Daniel J. Lindner, Fei Zhong, Clark W. Distelhorst, Mitchell R. Smith, Claudiu Cotta, Yan Xu, Sujatha Chilakala, Rebecca R. Kuang, Samantha Tall, Frederic J. Reu Jun 2016

Novel Protein Disulfide Isomerase Inhibitor With Anticancer Activity In Multiple Myeloma, Sergei Vatolin, James G. Phillips, Babal K. Jha, Shravya Govindgari, Jennifer Hu, Dale Grabowski, Yvonne Parker, Daniel J. Lindner, Fei Zhong, Clark W. Distelhorst, Mitchell R. Smith, Claudiu Cotta, Yan Xu, Sujatha Chilakala, Rebecca R. Kuang, Samantha Tall, Frederic J. Reu

Chemistry Faculty Publications

Multiple myeloma cells secrete more disulfide bond–rich proteins than any other mammalian cell. Thus, inhibition of protein disulfide isomerases (PDI) required for protein folding in the endoplasmic reticulum (ER) should increase ER stress beyond repair in this incurable cancer. Here, we report the mechanistically unbiased discovery of a novel PDI-inhibiting compound with antimyeloma activity. We screened a 30,355 small-molecule library using a multilayered multiple myeloma cell–based cytotoxicity assay that modeled disease niche, normal liver, kidney, and bone marrow. CCF642, a bone marrow–sparing compound, exhibited a submicromolar IC50 in 10 of 10 multiple myeloma cell lines. An active biotinylated analog …

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Criteria For Selecting Pegylation Sites On Proteins For Higher Thermodynamic Stability, Paul B. Lawrence Jun 2016

Criteria For Selecting Pegylation Sites On Proteins For Higher Thermodynamic Stability, Paul B. Lawrence

Theses and Dissertations

PEGylation of protein side-chains has been used for more than 30 years to enhance the pharmacokinetic properties of protein drugs, and has been enabled by the recent development of many chemoselective reactions for protein side-chain modification. However, there are no structure- or sequence-based guidelines for selecting sites that provide optimal PEG-based pharmacokinetic enhancement with minimal loss to biological activity. Chapter 1 is a brief introduction to protein PEGylation. In chapter 2 we use the WW domain of the human protein Pin 1 (WW) as a model system to probe the impact of PEG on protein conformational stability. Using a combination …

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Coupling Between Magnetic Exchange And Charge Activation In Cu-Doped Lafeo3, Emir Dogdibegovic, Qingsheng Cai, William Joseph James, William B. Yelon, Harlan U. Anderson, Jin Bo Yang, Xiao Dong Zhou Jun 2016

Coupling Between Magnetic Exchange And Charge Activation In Cu-Doped Lafeo3, Emir Dogdibegovic, Qingsheng Cai, William Joseph James, William B. Yelon, Harlan U. Anderson, Jin Bo Yang, Xiao Dong Zhou

Chemistry Faculty Research & Creative Works

Material research on perovskite-type oxides (ABO3) has been driven by the recognition of their unique properties primarily attributed to the presence of oxygen octahedron (BO6). Since 2003, the discovery of strong coupling in TbMnO3 and BiFeO3 has stimulated new interests in understanding the relationship between magnetic and electric properties in perovskites. In this article, we report our recent work on the magnetic superexchange interaction and charge formation in copper-doped LaFeO3 using high-temperature neutron diffraction and thermoelectric measurements. In situ neutron diffraction measurements show a loss of antiferromagnetic ordering above 450°C. With an increase …

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Water Quality In Selected Small Drinking Water Systems Of Missouri Rural Communities, Bin Hua, Ruipu Mu, Honglan Shi, Enos Inniss, John Yang Jun 2016

Water Quality In Selected Small Drinking Water Systems Of Missouri Rural Communities, Bin Hua, Ruipu Mu, Honglan Shi, Enos Inniss, John Yang

Chemistry Faculty Research & Creative Works

Small drinking water treatment systems (serving < 10,000 population) in rural communities frequently encounter multiple challenges in water quality and federal regulatory compliance, especially the disinfection byproduct (DBP) regulations, due to source water variations, limited resources, and aging infrastructures. Unlike most studies on the DBP control using synthetic water in laboratory settings, this research aimed to identify the major water quality issues confronting small systems in the state of Missouri (MO), the United States of America (USA). Three small systems were selected based on source water and geographic locations. Water samples were collected quarterly from each major treatment process during the period of May 2012 to March 2013 and analyzed to identify the treatment effectiveness and potential water quality issues in each small system. Results of water quality characterization showed that the major water quality issue in the selected small systems was the low efficiency of dissolved organic carbon (DOC) removal, especially the DOC species that are considered as the DBP precursors. Most collected water samples had a higher trihalomethane formation potential (THMFP) than the United States Environmental Protection Agency (USEPA) maximum contaminant limit (MCL) (80 µg/L). Based on the analysis of the treatment efficiency in each system, several strategies for water quality improvement were recommended, and a few of which have been implemented in the small systems, leading to improved drinking water quality and compliance with the USEPA DBP regulations. This study would provide a valuable aid to small system operators and local water authority in context of water quality improvement and the regulatory compliance.

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Programming Molecular Association And Viscoelastic Behavior In Protein Networks, Lawrence J. Dooling, Maren E. Buck, Wen Bin Zhang, David A. Tirrell Jun 2016

Programming Molecular Association And Viscoelastic Behavior In Protein Networks, Lawrence J. Dooling, Maren E. Buck, Wen Bin Zhang, David A. Tirrell

Chemistry: Faculty Publications

No abstract provided.

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Experimental Energy Levels And Partition Function Of The 12c2 Molecule, Tibor Furtenbacher, István Szabó, Attila G. Császár, Peter F. Bernath, Sergei N. Yurchenko, Jonathan Tennyson Jun 2016

Experimental Energy Levels And Partition Function Of The 12c2 Molecule, Tibor Furtenbacher, István Szabó, Attila G. Császár, Peter F. Bernath, Sergei N. Yurchenko, Jonathan Tennyson

Chemistry & Biochemistry Faculty Publications

The carbon dimer, the 12C2 molecule, is ubiquitous in astronomical environments. Experimental-quality rovibronic energy levels are reported for 12C2, based on rovibronic transitions measured for and among its singlet, triplet, and quintet electronic states, reported in 42 publications. The determination utilizes the Measured Active Rotational-Vibrational Energy Levels (MARVEL) technique. The 23,343 transitions measured experimentally and validated within this study determine 5699 rovibronic energy levels, 1325, 4309, and 65 levels for the singlet, triplet, and quintet states investigated, respectively. The MARVEL analysis provides rovibronic energies for six singlet, six triplet, and two quintet electronic states. For …

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Analyses Of Mrna Cleavage By Rele And The Role Of Trna Methyltransferase Trmd Using Bacterial Ribosome Profiling, Jae Yeon Hwang Jun 2016

Analyses Of Mrna Cleavage By Rele And The Role Of Trna Methyltransferase Trmd Using Bacterial Ribosome Profiling, Jae Yeon Hwang

Theses and Dissertations

Protein synthesis is a fundamental and ultimate process in living cells. Cells possess sophisticated machineries and continuously carry out complex processes. Monitoring protein synthesis in living cells not only inform us about the mechanism of translation but also deepen our insights about all aspects of life. Understanding the structure and mechanism of the ribosome and its associated factors helped us enlarge our knowledge on protein synthesis. Recently, with the dramatic advances of high-throughput sequencing and bioinformatics, a new technique called ribosome profiling emerged. By retrieving mRNA fragments protected by translating ribosomes, ribosome profiling reveals global ribosome occupancy along mRNAs in …

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Carbon Nanotubes Affect The Toxicity Of Cuo Nanoparticles To Denitrification In Marine Sediments By Altering Cellular Internalization Of Nanoparticle, Xiong Zheng, Yinglong Su, Yinguang Chen, Rui Wan, Mu Li, Haining Huang, Xu Li Jun 2016

Carbon Nanotubes Affect The Toxicity Of Cuo Nanoparticles To Denitrification In Marine Sediments By Altering Cellular Internalization Of Nanoparticle, Xiong Zheng, Yinglong Su, Yinguang Chen, Rui Wan, Mu Li, Haining Huang, Xu Li

Department of Civil and Environmental Engineering: Faculty Publications

Denitrification is an important pathway for nitrate transformation in marine sediments, and this process has been observed to be negatively affected by engineered nanomaterials. However, previous studies only focused on the potential effect of a certain type of nanomaterial on microbial denitrification. Here we show that the toxicity of CuO nanoparticles (NPs) to denitrification in marine sediments is highly affected by the presence of carbon nanotubes (CNTs). It was found that the removal efficiency of total NOX−-N (NO3−-N and NO2−-N) in the presence of CuO NPs was only 62.3%, but it …

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Optimizing Sequence Coverage For A Moderate Mass Protein In Nano-Electrospray Ionization Quadrupole Time-Of-Flight Mass Spectrometry, Ryan E. Matsuda, Venkata Kolli, Megan Woods, Eric D. Dodds, David S. Hage Jun 2016

Optimizing Sequence Coverage For A Moderate Mass Protein In Nano-Electrospray Ionization Quadrupole Time-Of-Flight Mass Spectrometry, Ryan E. Matsuda, Venkata Kolli, Megan Woods, Eric D. Dodds, David S. Hage

David Hage Publications

Sample pretreatment was optimized to obtain high sequence coverage for human serum albumin (HSA, 66.5 kDa) when using nano-electrospray ionization quadrupole time-of-flight mass spectrometry (nESI-Q-TOF-MS). Use of the final method with trypsin, Lys-C and Glu-C digests gave a combined coverage of 98.8%. The addition of peptide fractionation resulted in 99.7% coverage. These results were comparable to those obtained previously with matrixassisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The sample pretreatment/nESI-Q-TOF-MS method was also used with collision-induced dissociation to analyze HSA digests and to identify peptides that could be employed as internal mass calibrants in future studies of modifications to HSA.

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