Physical Sciences and Mathematics Commons^™

Speciation Of Elements Via A Sequential Extraction Procedure In Municipal Wastewater Biosolids From Three Rural Wwtp In East Texas (Usa), Kefa K. Onchoke

Faculty Publications

In this data article, the bioavailability of elements in municipal wastewater sludge (also known as biosolids) in samples collected from three treatment plants in East Texas, USA was evaluated. Although detailed speciation of the metals were assessed by using inductively coupled plasma optical spectroscopy (ICP-OES), and were discussed in the research article titled “Evaluating bioavailability of elements in municipal wastewater sludge (Biosolids) from three rural wastewater treatment plants in East Texas (USA) by a sequential extraction procedure” [1], this report presents the absolute raw concentrations and fractionations of the 26 metals from the biosolids (Nacogdoches Wastewater Sludge, Lufkin Wastewater Sludge, …

A Molecular Chemodosimeter To Probe “Closed Shell” Ions In Kidney Cells, Rashid Mia

Faculty Publications

Two quinidine-functionalized coumarin molecular probes have been synthesized and have been found to bind metal cations (Cd2+, Co2+, Cu2+, Fe2+, Hg2+, Ni2+, and Zn2+) with high affinity in organic–aqueous media (DMSO–HEPES). The chemodosimeters coordinate with the Zn2+ ions in a two-to-one ratio (molecular probe : Zn2+) with a log β of 10.0 M−2. Upon the addition of the closed-shell metal ions studied, a fluorescence turn-on via an excimer formation is seen at 542 nm due to the quinaldine moiety adopting a syn arrangement when coordinated to the metal Zn2+ ions. Confocal microscopy monitored free Zn2+ ions in the Human Embryonic …

Health Disparity And Covid-19—A Retrospective Analysis, Sanjay Sarkar, Archie Taylor, Pratik Dutta, Bidisha Sengupta, Debarshi Roy

Faculty Publications

Background and Aims

According to the World Health Organization (WHO), more than 75.7 million confirmed cases of coronavirus disease 2019 (COVID-19), a global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have been reported so far. Researchers are working relentlessly to find effective solutions to this catastrophe, using genomic sequence-based investigation, immunological analysis, and more. The role of health disparity has also emerged as an intriguing factor that made a huge impact on the lives of people.

Methods

We analyzed various factors that triggered the health disparity in the United States of America along with the rate of …

Transepithelial Anti-Neuroblastoma Response To Kale Among Four Vegetable Juices Using In Vitro Model Co-Culture System, John Piletz, Yuhan Mao, Debarshi Roy, Bilal Qizilbash, Eurielle Nkamssi, Enleyona Weir, Jessica Graham, Mary Emmanuel, Suwaira Iqbal, Kellie Brue, Bidisha Roy Sengupta

Faculty Publications

Juicing vegetables is thought to be an anticancer treatment. Support exists for a rank order of anticancer greens (kale > dandelion > lettuce > spinach) based on degrees of bioavailability of different phytochemicals, also offset by some noxious molecules (i.e., calcium-oxalate). We developed a new in vitro transepithelial anti-neuroblastoma model system. The juices were diluted as predicted once in the small intestine. They were applied to apical Caco-2Bbe1 cells atop dividing SH-SY5Y neuroblastoma cells, and changes in transepithelial electrical resistance (TEER) and cell growth were considered with juice spectroscopies. Studied first in monoculture, kale and dandelion were the most cytostatic juices on SH-SY5Ys, …

Data On Gc/Ms Elution Profile, 1h And 13c Nmr Spectra Of 1-, 3-, And 6-Nitrobenzo[A]Pyrenes, Kefa Karimu Onchoke

Faculty Publications

The data presented in this article is related to the research article entitled, “¹³C NMR Chemical Shift Assignments of Nitrated Benzo[a]pyrenes based on Two-dimensional Techniques and DFT/GIAO Calculations”, Kefa K. Onchoke, PeerJ., . The NMR spectral profiles of nitrated benzo[a]pyrenes is presented. Further, the article describes elution profiles of 1-, 3- and 6-NBaP, the acquisition of ¹H and ¹³C NMR data and the J-Coupling constants (which are useful for the assignment of peaks via 2D HMQC and HMBC techniques). The data presented is useful for developing structure-activity relationships for other nitrated polycyclic aromatic hydrocarbons (NPAHs)

Spectroscopic Study On Pseudomonas Aeruginosa Biofilm In The Presence Of The Aptamer-Dna Scaffolded Silver Nanoclusters, Bidisha Sengupta, Prakash Adhikari, Esther Mallet, Ronald Havner, Prabhakar Pradhan

Faculty Publications

We report the effectiveness of silver nanocluster (Ag-NC) against the biofilm of Pseudomonas aeruginosa (PA). Two DNA aptamers specific for PA and part of their sequences were chosen as templates for growing the Ag-NC. While circular dichroism (CD) studies determined the presence of secondary structures, UV/Vis absorption, and fluorescence spectroscopic studies confirmed the formation of the fluorescent Ag-NC on the DNA templates. Furthermore, mesoscopic physics-based partial wave spectroscopy (PWS) was used to analyze the backscattered light signal that can detect the degree of nanoscale mass density/refractive index fluctuations to identify the biofilm formation, comparatively among the different aptamers with respect …

Conformational Polymorphism In Organic Crystals: Structural And Functional Aspects - A Review, Bidisha Sengupta, Pradeep K. Sengupta, Romans Grant1, Matthew Beasley1, Benjamin Mason1, Tanesha Love1, Larissa Barroso9, Mariela Alvarado9, M S. Zaman

Faculty Publications

Polymorphism in organic crystals involves the formation of isomeric molecular identities. It is dependent on the structural arrangement due to inter-atomic interactions, as well as external stimuli, which include temperature, visible and UV radiation. Conformational polymorphism of organic crystalline molecules is often the result of isomerism due to the twisting and turning of angular bonds. The arrangement of the atoms supports different types of bonding mechanisms (which include hydrogen bonding) within the same compound. This, in turn, results in the formation of cis/trans configurational isomers or a proton transfer species (tautomer), having different functional properties. The conformers support the flexibility …

Sensitivity Analysis Of Computations Of The Vapor-Liquid Equilibria Of Methane + Methanol Or Glycols At Gas Hydrate Formation Conditions, Christopher E. Ozigagu, Anthony J. Duben

Faculty Publications

The Soave-Redlich-Kwong (SRK-EOS) and Peng-Robinson (PR-EOS) equations of state are used often to describe the behavior of pure substances and mixtures despite difficulties in handling substances, like water, with high polarity and hydrogen bonding. They were employed in studying the binary vapor-liquid equilibria (VLE) of methane + methanol, monoethylene glycol (MEG), and triethylene glycol (TEG). These liquids are used to inhibit the formation of gas hydrates. The investigation focused on the conditions at which methane-water clathrates can form 283.89 K to 323.56 K and 5.01 MPa to 18.48 MPa. The pressure of methane in methanol is overestimated by a factor …

Data On Ion Composition And X-Ray Diffraction Patterns Of Biosolids From Wastewater Treatment Plants In Lufkin And Nacogdoches, Texas, Usa, Kefa Karimu Onchoke, Christopher M. Franclemont, Paul W. Weatherford

Faculty Publications

The data presented in this article is related to the research article entitled, “Structural Characterization and Evaluation of Municipal Wastewater Sludge (Biosolids) from two Rural Wastewater Treatment Plants in East Texas, USA”, Onchoke, KK, Franclemont, C.M., Spectrochim. Acta A, In press[1]. The XRD profiles and composition of biosolids from wastewater treatment plant is presented. This study describes the composition of XRD crystalline phase patterns of the wastewater sludge. After the removal of the Ka2 peaks the d-spacing and hkl values were determined. In addition, the ion chromatographic profile of the seven anions (NO₃^-, NO_{2 …}

Determination Of Hexavalent Chromium (Cr(Vi)) Concentrations Via Ion Chromatography And Uv-Vis Spectrophotometry In Samples Collected From Nacogdoches Wastewater Treatment Plant, East Texas (Usa), Kefa Karimu Onchoke, Salomey A. Sasu

Faculty Publications

The concentration of hexavalent chromium (Cr(VI)), a toxic environmental pollutant and carcinogen, was determined in samples collected from Nacogdoches Wastewater Treatment Plant (NWWTP) using ion chromatography and UV-visible spectrophotometry (IC, UV-Vis). On reaction with 1,5-diphenylcarbazide (DPC) Cr+6 forms a 1,5-diphenylcarbazide-Cr(VI) complex, which is then analyzed at 530nm and 540nm, respectively. Via ion chromatography Cr(VI) concentrations were in the range of 0.00190 ± 0.0020 and 0.0010 ± 0.0006ppm at the influent and effluent, respectively. With the use of standard addition wastewater samples were spiked with a 0.5ppm Cr(VI) standard of various amounts and subsequently analyzed with UV-Vis spectrophotometry. The spiked concentrations …

Water Soluble Cationic Porphyrin Sensor For Detection Of Hg2+, Pb2+, Cd2+, And Cu2+, Matibur Zamadar, Christopher Orr, Miranda Uherek

Faculty Publications

Here we report the sensing properties of the aqueous solution of meso-tetra(N-methyl-4-pyridyl)porphine tetrachloride (1) for simultaneous detection of toxic metal ions by using UV-vis spectroscopy. Cationic porphyrin 1 displayed different electronic absorptions in UV-vis region upon interacting with Hg2+, Pb2+, Cd2+, and Cu2+ ions in neutral water solution at room temperature. Quite interestingly, the porphyrin 1 showed that it can function as a single optical chemical sensor and/or metal ion receptor capable of detecting two or more toxic metal ions, particularly Hg2+, Pb2+, and Cd2+ ions coexisting in a water sample. Porphyrin 1 in an aqueous solution provides a unique …

"High-Valent Copper In Biomimetic And Biological Oxidations", J. Brannon Gary

Faculty Publications

A long-standing debate in the Cu-O2 field has revolved around the relevance of the Cu(III) oxidation state in biological redox processes. The proposal of Cu(III) in biology is generally challenged as no spectroscopic or structural evidence exists currently for its presence. The reaction of synthetic Cu(I) complexes with O2 at low temperature in aprotic solvents provides the opportunity to investigate and define the chemical landscape of Cu-O2 species at a small molecule level of detail; eight different types are characterized structurally, three of which contain at least one Cu(III) center. Simple imidazole or histamine ligands are competent in these oxygenation …

"Sorbents For Carbon Dioxide Capture.", J. Brannon Gary

Faculty Publications

Provided herein are sorbents for carbon dioxide (CO₂) capture, such as from natural gas and coal-fired power plant flue gases, and uses thereof.

Evaluation Of The Performance Of A Rural Municipal Wastewater Treatment Plant In Nacogdoches, East Texas (Usa) (Abstract), Kefa Karimu Onchoke, Michael Janusa, Salomey Asantewaa Sasu

Faculty Publications

The performance of a rural wastewater treatment facility, Nacogdoches Wastewater Treatment Plant

(NWWTP), in East Texas, USA, was assessed from January 2013 through June 2014. The elemental concentrations (Na, Mg, Ca, Ni, Pb, Mn, Cr, Mo, and Cu, Al, As, B, Ba, Ag, Cd, Fe, Hg, K, Se, Zn, Co, P, and S) were measured using inductively coupled plasma optical emission spectrometry. The anion concentrations (Br−, NO3- , NO2- , PO34-,F−, Cl−, and SO24−) were measured by ion chromatography. In general, the NWWTP was found efficient in removal to ≥ 96% for metals. The removal efficiency for anions was in …

Theoretical Examination Of Solvent And R Group Dependence In Gold Thiolate Nanoparticle Synthesis, Suzanne M. Neidhart, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

The growth of gold thiolate nanoparticles can be affected by the solvent and the R group on the ligand. In this work, the difference between methanol and benzene solvents as well as the effect of alkyl (methyl) and aromatic (phenyl) thiols on the reaction energies and barrier heights is investigated theoretically. Density functional theory (DFT) calculations using the BP86 functional and a triple ζ polarized basis set show that the overall reaction favors methylthiol over phenylthiol with reaction energies of −0.54 and −0.39 eV in methanol, respectively. At the same level of theory, the methanol solvent is favored over the …

Prediction Of Nonradical Au (0)-Containing Precursors In Nanoparticle Growth Processes, Brian M. Barngrover, Timothy J. Manges, Christine M. Aikens

Faculty Publications

This density functional theory (DFT) investigation examines the formation of nonradical Au(0) species from the reduction of Au(I) species. The Au(I) complexes of interest are AuCl₂^–, AuBr₂^–, AuI₂^–, AuClPH₃, and AuCl(H)SCH₃⁽⁻⁾, which are precursors for gold nanoparticle and cluster formation. Reaction of two of the Au(I) species with a hydride results in ejection of two of the ligands and formation of Au₂ with two ligands still attached. AuX₂^– (where X = Cl, Br, or I) reactions eject two halides and form Au_{2 …}

A Td-Dft Study Of The Absorption Spectra Of Mono-Nitrated Fluoranthenes [Abstract], Kefa Karimu Onchoke

Faculty Publications

No abstract provided.

Electron Transfer By Excited Benzoquinone Anions: Slow Rates For Two-Electron Transitions, Matibur Zamadar, Andrew R. Cook, Anna Lewandowska-Andralojc, Richard Holroyd, Yan Jiang, Jin Bikalis, John R. Miller

Faculty Publications

Electron transfer (ET) rate constants from the lowest excited state of the radical anion of benzoquinone, BQ−•*, were measured in THF solution. Rate constants for bimolecular electron transfer reactions typically reach the diffusion-controlled limit when the free-energy change, ΔG°, reaches −0.3 eV. The rate constants for ET from BQ−•* are one-to-two decades smaller at this energy and do not reach the diffusion-controlled limit until −ΔG° is 1.5−2.0 eV. The rates are so slow probably because a second electron must also undergo a transition to make use of the energy of the excited state. Similarly, ET, from solvated electrons to neutral …

Toward Designed Singlet Fission: Solution Photophysics Of Two Indirectly Coupled Covalent Dimers Of 1,3-Diphenylisobenzofuran, Justin C. Johnson, Akin Akdag, Matibur Zamadar, Xudong Chen, Andrew F. Schwerin, Irina Paci, Millicent B. Smith, Zdenek Havlas, John R. Miller, Mark A. Ratner, Arthur J. Nozik, Josef Michl

Faculty Publications

In order to identify optimal conditions for singlet fission, we are examining the photophysics of 1,3- diphenylisobenzofuran (1) dimers covalently coupled in various ways. In the two dimers studied presently, the coupling is weak. The subunits are linked via the para position of one of the phenyl substituents, in one case (2) through a CH2 linker and in the other (3) directly, but with methyl substituents in ortho positions forcing a nearly perpendicular twist between the two joint phenyl rings. The measurements are accompanied with density functional theory (DFT) and timedependent DFT (TD-DFT) calculations. Although in neat solid state, 1 …

Ammonium Sulfate Precipitation Combined With Liquid Chromatography Is Sufficient For Purification Of Bovine Serum Albumin That Is Suitable For Most Routine Laboratory Applications, Odutayo O. Odunuge, Alina Shazhko

Faculty Publications

The use of bovine serum albumin (BSA) in routine biochemical assays such as restriction enzyme digestion and immunodetection is plagued largely by two common contaminants, DNase and immunoglobulins G (IgGs). Acetylation of BSA to inactivate DNase limits its use as a protein standard due to interference with color development in assays such as Lowry’s. In spite of the availability of inexpensive BSA, its purification involves several cumbersome and time-consuming steps. In this work, we employed a modified strategy of ammonium sulfate precipitation coupled with liquid chromatography to purify BSA that is free of DNase and IgGs. Purified BSA tested negative …

A Dft Study Of Vibrational Spectra And Mutagenicity Predictions Of Mononitrated Fluoranthenes [Abstract], Kefa Karimu Onchoke, Jorge Ojeda

Faculty Publications

No abstract provided.

Oxidation Of Gold Clusters By Thiols, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

The formation of gold–thiolate nanoparticles via oxidation of gold clusters by thiols is examined in this work. Using the BP86 density functional with a triple ζ basis set, the adsorption of methylthiol onto various gold clusters Au_n^Z (n = 1–8, 12, 13, 20; Z = 0, −1, +1) and Au₃₈⁴⁺ is investigated. The rate-limiting step for the reaction of one thiol with the gold cluster is the dissociation of the thiol proton; the resulting hydrogen atom can move around the gold cluster relatively freely. The addition of a second thiol can lead to H_{2 …}

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 …

Vibrational And Electronic Spectra Of 9, 10-Dihydrobenzo (A) Pyren-7 (8h)-One And 7, 8, 9, 10-Tetrahydrobenzo (A) Pyrene: An Experimental And Computational Study [Abstract], Kefa Karimu Onchoke, Prabir K. Dutta, Matthew Parks, Mireya Martinez

Faculty Publications

No abstract provided.

Experimental And Theoretical Study Of Vibrational Spectra Of 3-Nitrofluoranthene [Abstract], Kefa Karimu Onchoke, Matthew Parks

Faculty Publications

No abstract provided.

Photosensitizer Drug Delivery Via An Optical Fiber, Matibur Zamadar, Goutam Ghosh, Adaic Kapillai Mahendran, Mihaela Minnis, Bonnie I. Kruft, Ashwini Ghogare, David Aebisher, Alexander Greer

Faculty Publications

: An optical fiber has been developed with a maneuverable miniprobe tip that sparges O2 gas and photodetaches pheophorbide (sensitizer) molecules. Singlet oxygen is produced at the probe tip surface which reacts with an alkene spacer group releasing sensitizer upon fragmentation of a dioxetane intermediate. Optimal sensitizer photorelease occurred when the probe tip was loaded with 60 nmol sensitizer, where crowding of the pheophorbide molecules and self-quenching were kept to a minimum. The fiber optic tip delivered pheophorbide molecules and singlet oxygen to discrete locations. The 60 nmol sensitizer was delivered into petrolatum; however, sensitizer release was less efficient in …

Dft/Td-Dft Investigation Of Optical Absorption Spectra, Electron Affinities, And Ionization Potentials Of Mono-Nitrated Benzanthrones [Abstract], Kefa Karimu Onchoke

Faculty Publications

No abstract provided.

Incremental Binding Energies Of Gold (I) And Silver (I) Thiolate Clusters, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

Density functional theory is used to find incremental fragmentation energy, overall dissociation energy, and average monomer fragmentation energy of cyclic gold(I) thiolate clusters and anionic chain structures of gold(I) and silver(I) thiolate clusters as a measure of the relative stability of these systems. Two different functionals, BP86 and PBE, and two different basis sets, TZP and QZ4P, are employed. Anionic chains are examined with various residue groups including hydrogen, methyl, and phenyl. Hydrogen and methyl are shown to have approximately the same binding energy, which is higher than phenyl. Gold–thiolate clusters are bound more strongly than corresponding silver clusters. Lastly, …

Electron And Hydride Addition To Gold (I) Thiolate Oligomers: Implications For Gold–Thiolate Nanoparticle Growth Mechanisms, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

Electron and hydride addition to Au(I):SR oligomers is investigated using density functional theory. Cyclic and chain-like clusters are examined in this work. Dissociation to Au^– ions and Au_n(SR)_n+1^– chains is observed after 2–4 electrons are added to these systems. The free thiolate (SR^–) is rarely produced in this work; dissociation of Au^– is preferred over dissociation of SR^–. Electron affinities calculated in gas phase, toluene, and water suggest that the electron addition process is unlikely, although it may be possible in polar solvents. In contrast, hydride addition to Au(I):SR …