Chemistry Commons^™

Ti2ctx Mxene-Based All-Optical Modulator, Jun Yi, Jie Li, Shuohan Huang, Longyu Hu, Lili Miao, Chujun Zhao, Shuangchun Wen, Vadym Mochalin, Apparao M. Rao

Chemistry Faculty Research & Creative Works

MXenes, a new class of 2D transition metal carbides, nitrides, and carbonitrides, have attracted much attention due to their outstanding properties. Here, we report the broadband spatial self-phase modulation of Ti₂CT_x MXene nanosheets dispersed in deionized water in the visible to near-infrared regime, highlighting the broadband nonlinear optical (NLO) response of Ti₂CT_x MXene. Using ultrafast pulsed laser excitation, the nonlinear refractive index n2 and the third-order nonlinear susceptibility (Formula presented.) of Ti₂CT_x MXene were measured to be ∼10−13 m2/W and ∼ 10−10 esu, respectively. Leveraging the large optical nonlinearity of Ti …

A Cascade Reaction Of Cinnamyl Azides With Acrylates Directly Generates Tetrahydro-Pyrrolo-Pyrazole Heterocycles, Angela S. Carlson, En Chih Liu, Joseph J. Topczewski

Chemistry Faculty Research & Creative Works

Developing reactions to generate complex and modular building blocks in a concise and direct fashion remains a contemporary synthetic challenge. This work describes a stereoselective cascade reaction between allylic azides and acrylates that directly generates tetrahydro-pyrrolo-pyrazole ring systems. These products contain up to four contiguous stereocenters, two of which may be tetrasubstituted carbon atoms attached to a nitrogen atom. Over 30 examples are provided with an average isolated yield of 71% (ranging from 40% to 94%). The reaction was easily scaled to use more than one gram of starting material, and the products can be readily diversified.

The Microbiota-Gut-Brain Axis Heart Shunt Part I: The French Paradox, Heart Disease And The Microbiota, M. Obrenovich, B. Siddiqui, B. Mccloskey, Prakash Reddy

Chemistry Faculty Research & Creative Works

It has been well established that a vegetarian and polyphenol-rich diet, including fruits, vegetables, teas, juices, wine, indigestible fiber and whole grains, provide health-promoting phytochemicals and phytonutrients that are beneficial for the heart and brain. What is not well-characterized is the affect these foods have when co-metabolized within our dynamic gut and its colonizing flora. The concept of a heart shunt within the microbiota-gut-brain axis underscores the close association between brain and heart health and the so-called "French paradox" offers clues for understanding neurodegenerative and cerebrovascular diseases. Moreover, oxidation-redox reactions and redox properties of so-called brain and heart-protective foods are …

Gram-Scale Synthesis Of 2,5-Difluoro-7,7,8,8-Tetracyanoquinodimethane (F2-Tcnq), En Chih Liu, Joseph J. Topczewski

Chemistry Faculty Research & Creative Works

The molecule 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane (F2-TCNQ) is an organic semiconductor with many promising properties, including high charge mobility (μ). However, an efficient gram-scale synthesis of F2-TCNQ has not been fully documented. Herein, we report a synthesis of F2-TCNQ via a three-step sequence that affords F2-TCNQ in 58% cumulative yield. This synthesis was used to prepare more than 1 g of F2-TCNQ.

Fiber-Optic Micro-Probes For Measuring Acidity Level, Temperature, And Antigens, Yinfa Ma, Honglan Shi, Qingbo Yang, Hai Xiao

Chemistry Faculty Research & Creative Works

A pH micro-probe, a temperature micro-probe, and an immuno-based micro-probe each include a shaft for transmuting an input light signal and a tip for inserting into a cell or other substance for measuring pH, temperature, and/or antigens. The pH micro-probe and the temperature micro-probe each include a luminescent material positioned on the tip of the micro-probe. The light signal excites the luminescent material so that the luminescent material emits a luminescent light signal. The luminescent light signal has a property value dependent on the pH or temperature being measured and reflects back through the shaft for being measured by a …

A Neuro-Ontology For The Neurological Examination, Daniel B. Hier, Steven U. Brint

Chemistry Faculty Research & Creative Works

Background: The Use of Clinical Data in Electronic Health Records for Machine-Learning or Data Analytics Depends on the Conversion of Free Text into Machine-Readable Codes. We Have Examined the Feasibility of Capturing the Neurological Examination as Machine-Readable Codes based on UMLS Metathesaurus Concepts. Methods: We Created a Target Ontology for Capturing the Neurological Examination using 1100 Concepts from the UMLS Metathesaurus. We Created a Dataset of 2386 Test-Phrases based on 419 Published Neurological Cases. We Then Mapped the Test-Phrases to the Target Ontology. Results: We Were Able to Map All of the 2386 Test-Phrases to 601 Unique UMLS Concepts. a …

Polyphenols In Alzheimer’S Disease And In The Gut–Brain Axis, V. Prakash Reddy, Puspa Aryal, Sara Robinson, Raheemat Rafiu, Mark Obrenovich, George Perry

Chemistry Faculty Research & Creative Works

Polyphenolic antioxidants, including dietary plant lignans, modulate the gut–brain axis, which involves transformation of these polyphenolic compounds into physiologically active and neuroprotector compounds (called human lignans) through gut bacterial metabolism. These gut bacterial metabolites exert their neuroprotective effects in various neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), and also have protective effects against other diseases, such as cardiovascular diseases, cancer, and diabetes. For example, enterolactone and enterodiol, the therapeutically relevant polyphenols, are formed as the secondary gut bacterial metabolites of lignans, the non-flavonoid polyphenolic compounds found in plant-based foods. These compounds are also acetylcholinesterase inhibitors and …

Nanodiamonds And Carbon Nano-Onions Ceramic Composites And Their Applications, Ibrahim Munkaila Abdullahi

Masters Theses

"Luminescent nanodiamonds are photostable non-blinking fluorescent biocompatible, non-toxic, functional Zable materials made from high-pressure high temperature (HPHT) microcrystalline diamonds. For long, the scientific community has been investigating for a clean, efficient and cost-effective technique to reduce the size of fluorescent microcrystalline diamond into nanodiamonds. Their color center, responsible for the fluorescent properties are crucial for their applications, including biomedical imaging, nano sensing, quantum computing etc, and therefore should not be affected significantly by the method of size reduction applied. A novel size reduction technique that is based on explosive fragmentation was developed and the corresponding fragmented diamonds obtained were characterized …

A Square Channel Vanadium Phosphite Framework As A High Voltage Cathode For Li- And Na-Ion Batteries, Prashanth Sandineni, Pranal Madria, Kartik Ghosh, Amitava Choudhury

Chemistry Faculty Research & Creative Works

A vanadium phosphite compound, LiV(HPO3)2, has been synthesized using low-melting flux composed of phosphorous acid and lithium hydroxide. The crystal structure of the compound as refined using the Rietveld method matched with the previously reported unit cell parameters (space group: I42d, a = b = 10.5987(4), c = 9.9843(5) Å). It has a 3-dimensional open-framework structure with intersecting channels. Eight-membered ring square channels can be viewed along the c-axis and 6-membered ring channels along the a- and b-axis. The Li-ions are located in the six-membered ring channels exactly at the opening window to the eight-membered ring channels. The magnetic property …

Revealing The Hidden Hyperfine Interactions In Ε-Iron, Dimitrios Bessas, Ilya Sergueev, Konstantin Glazyrin, Cornelius Strohm, Ilya Kupenko, Daniel G. Merkel, Gary J. Long, Fernande Grandjean, Aleksandr I. Chumakov, Rudolf Ruffer

Chemistry Faculty Research & Creative Works

Herein, evidence for the long-sought finite hyperfine interaction in the high-pressure hexagonal close-packed ε-iron is gained through synchrotron radiation perturbed angular correlation spectroscopy. This method yields an energy splitting of 3.5(5)neV between the m_Ie= ± 1/2 and m_Ie = ± 3/2 nuclear sublevels of the iron-57 14.412-keV nuclear excited state at 30(1)GPa and room temperature. This energy splitting is related to a nuclear quadrupole hyperfine interaction with an electric field gradient of eq=1.2(2) x 10¹⁶V/cm². However, there is still a possibility that the splitting of the iron-57 nuclear levels is related …

Synthesis And Thermodynamic Characterization Of Free And Surface Water Of Colloidal Unimolecular Polymer (Cup) Particles Utilizing Dsc And Tga, Peng Geng

Doctoral Dissertations

“Colloidal Unimolecular Polymer (CUP) is spheroidal nanoscale polymer particle (3-9 nm) with charged hydrophilic gruops on the surface and a hydrophobic core. The formation of CUPs involves a simple free radical polymerization and a water reduction process. CUPs are thermodynamically stable in water, molecular weight, particle size and charge density can be designed and controlled. CUPs have a layer of surface associated water, due to the small particle size, the surface water/CUP volume ratio is ultra-high. Therefore, CUP is a very promising candidate to investigate the thermodynamic of surface water characteristics. In addition, CUP solution is free of surfactant and …

Tools To Evaluate Nanodiamond-Mediated Delivery Of Tiopronin For Cataract Prevention, Justin Beltz

Doctoral Dissertations

”There is a growing demand for non-surgical means of cataract treatment. This dissertation presents three bodies of work that reflect the early-stage development of eye drop formulations aimed at delaying cataract progression. These formulations consist of the antioxidant 2-mercaptopropionylglycine (MPG) loaded onto nanodiamond particles.

Cataractogenesis is linked to oxidative damage to lens proteins. To investigate the potential of MPG for protection against oxidative damage, A549 cells were incubated in 0.6 mM tert-butylhydroperoxide (tBHP). Cells exposed to tBHP without MPG exhibited elevated levels of reactive oxygen species, which led to the depletion of the vital antioxidant glutathione and, ultimately, apoptosis. Co-administration …

Continuous-Flow Synthesis Of Fine Chemicals And Pharmaceutical Compounds Over Intelligent Organocatalysts With Bifunctional Reactivity, Abdo-Alslam Alwakwak

Doctoral Dissertations

“Many biological systems that utilize organic active sites to catalyze reactions under mild conditions invoke cooperative catalytic pathways, whereby two or more active sites work together to activate the reactant(s). The use of cooperative (bifunctional) catalysts and continuous flow chemistry (a reaction within the narrow channels of a micro‐ or microfluidic reactor) are commonplace in sustainable chemical transformation and attract a great deal of interest with respect to economic and environmentally-sustainable production of fine chemicals, pharmaceuticals, and agrochemicals, water treatment, as well as upgrading of biomass feedstocks. Although, some methods have been developed for immobilization of bifunctional catalysts for cooperative …

Structurally And Electronically Diverse Polyanion-Based Cathode Materials For Alkali-Ion Batteries, Prashanth Sandineni

Doctoral Dissertations

”Through this investigation polyanion-based cathode materials including sulfates, phosphates, and phosphites of transition metal have been synthesized for lithium and sodium-ion batteries and their electrochemical performances were evaluated. The emphasis was on soft chemical routes to discover metastable phases which are often missed in high temperature synthesis. Iron-based compounds were the main focus of this investigation, however, concurrently a few vanadium-analogues of iron compounds were investigated to evaluate the effect of multi-electron process on achievable voltage and capacity.

This investigation resulted in the discovery of several compounds with unique crystal structures, namely AFe₃(SO₄)₂(OH)_{6 …}

Transition Metal Chalcogenide Hybrid Systems As Catalysts For Energy Conversion And Biosensing, Siddesh Umapathi

Doctoral Dissertations

"Generation of hydrogen and oxygen through catalyst-aided water splitting which has immense applications in metal air batteries, PEM fuel cells and solar to fuel energy production, has been one of the critical topics in recent times. The state of art oxygen evolution reaction (OER), oxygen reduction reaction (ORR), hydrogen evolution reaction (HER) catalysts are mostly comprised of precious metals. The current challenge lies in replacing these precious metal-based catalysts with non-precious earth-abundant materials without compromising catalytic efficiency.

This research explores mixed metal selenides containing Fe-Ni, Fe-Co and RhSe which were hydrothermally synthesized and/or electrodeposited and tested for OER and ORR …

Stabilization Dynamics Of The Ozone Molecular System, Sangeeta Sur

Doctoral Dissertations

"The observation of larger-than-expected concentrations of heavier isotopologues of ozone known as 'ozone isotopic anomaly' in the stratosphere is a mass-independent effect (in contrast to most kinetic isotope effects familiar to chemists) that is traced back to the recombination process in the formation of ozone in the Chapman cycle. Understanding the relative efficiencies (often approximated as equal for different isotopologues) of the stabilization step (some of the details of which are still a mystery) which involves energy transfer from a highly excited ozone molecule to a third body, M (argon atom in this case) to form stable ozone is a …

Two Algorithms For The Reorganisation Of The Problem List By Organ System, Daniel B. Hier, Joshua Pearson

Chemistry Faculty Research & Creative Works

Objective Long Problem Lists Can Be Challenging to Use. Reorganization of the Problem List by Organ System is a Strategy for Making Long Problem Lists More Manageable. Methods in a Small-Town Primary Care Setting, We Examined 4950 Unique Problem Lists over 5 Years (24 033 Total Problems and 2170 Unique Problems) from Our Electronic Health Record. All Problems Were Mapped to the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) and SNOMED CT Codes. We Developed Two Different Algorithms for Reorganizing the Problem List by Organ System based on Either the ICD-10-CM or the SNOMED CT Code. Results the …

Cuinse₂ Nanotube Arrays For Efficient Solar Energy Conversion, Wipula Priya Liyanage, Manashi Nath

Chemistry Faculty Research & Creative Works

Highly uniform and vertically aligned p-type CuInSe₂ (CISe) nanotube arrays were fabricated through a unique protocol, incorporating confined electrodeposition on lithographically patterned nanoelectrodes. This protocol can be readily adapted to fabricate nanotube arrays of other photoabsorber and functional materials with precisely controllable design parameters. Ternary CISe nanotube arrays were electrodeposited congruently from a single electrolytic bath and the resulting nanotube arrays were studied through powder X-ray diffraction as well as elemental analysis which revealed compositional purity. Detailed photoelectrochemical (PEC) characterizations in a liquid junction cell were also carried out to investigate the photoconversion efficiency. It was observed that the …

Facile One-Pot Synthesis Of Nico₂Se₄-Rgo On Ni Foam For High Performance Hybrid Supercapacitors, Bahareh Golrokh Amin, Jahangir Masud, Manashi Nath

Chemistry Faculty Research & Creative Works

A facile, innovative synthesis for the fabrication of NiCo₂Se₄-rGO on a Ni foam nanocomposite via a simple hydrothermal reaction is proposed. The as-prepared NiCo₂Se₄-rGO@Ni foam electrode was tested through pxrd, TEM, SEM, and EDS to characterize the morphology and the purity of the material. The bimetallic electrode exhibited outstanding electrochemical performance with a high specific capacitance of 2038.55 F g^-1 at 1 A g^-1. NiCo₂Se₄-rGO@Ni foam exhibits an extensive cycling stability after 1000 cycles by retaining 90% of its initial capacity. A superior energy density …

Enhanced Piezoresponse And Nonlinear Optical Properties Of Fluorinated Self-Assembled Peptide Nanotubes, Soma Khanra, Sandra V. Vassiliades, Wendel A. Alves, Kaidi Yang, Rainer Glaser, Kartik Ghosh, Payal Bhattacharya, Ping Yu, Suchismita Guha

Chemistry Faculty Research & Creative Works

Self-assembled L,L-diphenylalanine (FF) nanostructures offer an attractive platform for photonics and nonlinear optics. The nonlinear optical (NLO) coefficients of FF nanotubes depend on the diameter of the tube [S. Khanra et al. Phys. Chem. Chem. Phys. 19(4), 3084-3093 (2017)]. To further enhance the NLO properties of FF, we search for structural modifications. Here, we report on the synthesis of fluorinated FF dipeptides by replacing one ortho-hydrogen atom in each of the phenyl groups of FF by a fluorine atom. Density-functional theoretical calculations yield insights into minimum energy conformers of fluorinated FF (Fl-FF). Fl-FF self-assembles akin to FF into micron-length tubes. …

Novel Highly Porous Ceramic And Metal Aerogels From Xerogel Powder Precursors, And Methods For Their Production And Use, Nicholas Leventis, Chariklia Sotiriou-Leventis, Malik Adnan Saeed, Parwani Rewatkar, Tahereh Taghvaee

Chemistry Faculty Research & Creative Works

The present invention discloses novel methods for producing highly porous ceramic and/or metal aerogel monolithic objects that are hard, sturdy, and resistant to high temperatures. These methods comprise preparing nanoparticulate oxides of metals and/or metalloids via a step of vigorous stirring to prevent gelation, preparing polymer-modified xerogel powder compositions by reacting said nanoparticulate oxides with one or more polyfunctional monomers, compressing said polymer-modified xerogel powder compositions into shaped compacts, and carbothermal conversion of the shaped xerogel compacts via pyrolysis to provide the highly porous ceramic and/or metal aerogel monolithic objects that have the same shapes as to their corresponding xerogel …

Co-Localization Of Dna I-Motif-Forming Sequences And 5-Hydroxymethyl-Cytosines In Human Embryonic Stem Cells, Yogini P. Bhavsar-Jog, Eric Van Dornshuld, Tracy A. Brooks, Gregory S. Tschumper, Randy M. Wadkins

Chemistry Faculty Research & Creative Works

G-quadruplexes (G4s) and i-motifs (iMs) are tetraplex DNA structures. Sequences capable of forming G4/iMs are abundant near the transcription start sites (TSS) of several genes. G4/iMs affect gene expression in vitro. Depending on the gene, the presence of G4/iMs can enhance or suppress expression, making it challenging to discern the underlying mechanism by which they operate. Factors affecting G4/iM structures can provide additional insight into their mechanism of regulation. One such factor is epigenetic modification. The 5-hydroxymethylated cytosines (5hmCs) are epigenetic modifications that occur abundantly in human embryonic stem cells (hESC). The 5hmCs, like G4/iMs, are known to participate in …

Double-Click Enables Synthesis Of Chemical Libraries For Drug Discovery, Joseph J. Topczewski, En Chih Liu

Chemistry Faculty Research & Creative Works

No abstract provided.

Electrochemistry Of Illusive Barbosalite, Fe²⁺Fe³⁺ 2(Po₄)₂(Oh)₂: An Iron Phosphate Related To Lipscombite Structure, Prashanth Sandineni, Kartik Ghosh, Amitava Choudhury

Chemistry Faculty Research & Creative Works

Barbosalite, an iron hydroxy-phosphate belonging to the family of Lazulite has been synthesized using hydrothermal route and its electrochemical property is investigated for the first time with respect to Li-ion batteries. The structure, as determined from single-crystal X-ray diffraction data, built up of undulating layers of FeO₆ octahedra, consisting of trimers and PO₄ tetrahedral units. Magnetic susceptibility measurements show predominant overall anti-ferromagnetic interactions and room temperature 57Fe Mössbauer spectroscopic studies confirm the mixed 3+ and 2+ oxidation states of Fe in the compound. The compound is stable up to 400°C and undergo facile electrochemical lithium insertion. Galvanostatic charge-discharge …

State-To-State Inelastic Rotational Cross Sections In Five-Atom Systems With The Multiconfiguration Time Dependent Hartree Method, Steve Ndengue, Yohann Scribano, Fabien Gatti, Richard Dawes

Chemistry Faculty Research & Creative Works

We present a MultiConfiguration Time Dependent Hartree (MCTDH) method as an attractive alternative approach to the usual quantum close-coupling method that approaches some computational limits in the calculation of rotational excitation (and de-excitation) between polyatomic molecules (here collisions between triatomic and diatomic rigid molecules). We have performed a computational investigation of the rotational (de-)excitation of the benchmark rigid rotor H₂O-H₂ system on a recently developed Potential Energy Surface of the complex using the MCTDH method. We focus here on excitations and de-excitations from the 0₀₀, 1₁₁, and 1₁₀ states of H_{2 …}

Low-Cost, Ambient-Dried, Superhydrophobic, High Strength, Thermally Insulating, And Thermally Resilient Polybenzoxazine Aerogels, Sadeq Malakooti, Guoqiang Qin, Chandana Mandal, Rushi Soni, Tahereh Taghvaee, Yao Ren, Huiluo Chen, Nicholas Tsao, James Shiao, Shameek Sushil Kulkarni, Chariklia Sotiriou-Leventis, Nicholas Leventis, Hongbing Lu

Chemistry Faculty Research & Creative Works

A family of ambient-dried poly benzoxazine aerogels is prepared with a facile and scalable process as a high-performance polymeric aerogel with strong and robust thermomechanical properties at elevated temperatures. Those materials are inherently flame-retardant and superhydrophobic over the entire bulk density range (0.24-0.46 g cm-3). In addition, they are mechanically strong with strengths (e.g., 1 MPa at 0.24 g cm-3 at room temperature) higher than those of other high-performance aerogels of similar density, including polyimide and polyamide (Kevlar-like) aerogels as well as polymer-cross-linked X-silica and X-Vanadia aerogels, at a significantly lower cost. Furthermore, unlike most other glassy polymeric materials, the …

Computational Study Of The Ro-Vibrational Spectrum Of Co-Co₂, Eduardo Castro-Juarez, Xiao-Gang Wang, Tucker Carrington Jr., Ernesto Quintas-Sánchez, Richard Dawes

Chemistry Faculty Research & Creative Works

An accurate ab initio ground-state intermolecular potential energy surface (PES) was determined for the CO-CO₂ van der Waals dimer. The Lanczos algorithm was used to compute rovibrational energies on this PES. For both the C-in and O-in T-shaped isomers, the fundamental transition frequencies agree well with previous experimental results. We confirm that the in-plane states previously observed are geared states. In addition, we have computed and assigned many other vibrational states. The rotational constants we determine from J = 1 energy levels agree well with their experimental counterparts. Planar and out-of-plane cuts of some of the wavefunctions we compute …

Enhanced Flocculation Using Drinking Water Treatment Plant Sedimentation Residual Solids, Sandhya Rao Poleneni, Enos Inniss, Honglan Shi, John Yang, Bin Hua, Joseph Clamp

Chemistry Faculty Research & Creative Works

Inefficient removal of total organic carbon (TOC) leads to the formation of carcinogenic disinfection by-products (DBPs) when a disinfectant is added. This study is performed in an effort to develop a simple, non-invasive, and cost-effective technology that will effectively lower organic precursors by having water utilities reuse their treatment residual solids. Jar tests are used to simulate drinking water treatment processes with coagulants-aluminum sulfate (alum), poly-aluminum chloride (PACl), and ferric chloride and their residual solids. Ten coagulant-to-residual (C/R) ratios are tested with water from the Missouri River at Coopers Landing in Columbia, MO versus alluvial ground waters. This treatment results …

Adhesion Of Two-Dimensional Titanium Carbides (Mxenes) And Graphene To Silicon, Yanxiao Li, Shuohan Huang, Congjie Wei, Chenglin Wu, Vadym Mochalin

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Two-dimensional transition metal carbides (MXenes) have attracted a great interest of the research community as a relatively recently discovered large class of materials with unique electronic and optical properties. Understanding of adhesion between MXenes and various substrates is critically important for MXene device fabrication and performance. We report results of direct atomic force microscopy (AFM) measurements of adhesion of two MXenes (Ti₃C₂T_x and Ti₂CT_x) with a SiO₂ coated Si spherical tip. The Maugis-Dugdale theory was applied to convert the AFM measured adhesion force to adhesion energy, while taking into account …

The Ideal And Real Gas Heat Capacity Of Cesium Atoms At High Temperatures, Louis Biolsi, Michael Biolsi

Chemistry Faculty Research & Creative Works

The Ideal Gas Heat Capacity, C_p, of Cesium Atoms is Calculated to High Temperatures using Statistical Mechanics. There Are a Large Number of Electronic States in the State Sum that Determines the Partition Function: 174 Known Levels for Cesium Atoms Below the First Ionization Potential. Thus, at High Temperatures, C_p Becomes Very Large Unless the Number of Contributing States is Constrained. Two Arguments Are Used to Do This. First, at High Temperatures, the Increased Size of the Atoms Constrains the Sum (Bethe Method). Second, the Existence of Interacting Charged Species at Higher Temperatures, Which Lowers the Ionization …