Physical Sciences and Mathematics Commons^™

Design, Evolution, And Evaluation Of A General Chemistry-Bridging Course, Scott A. Reid

Chemistry Faculty Research and Publications

General chemistry I/II courses are important gateway courses for a variety of STEM majors, as poor performance in these courses is often associated with lower rates of student success and retention. Much research has explored preparatory or remedial strategies to improve student outcomes. In this article, we report a different approach, which involved the development of a bridging or intervention course designed to capture students who are not or have not succeeded in general chemistry I and prepare them to retake the course in the following semester or summer. The course was initially developed as an eight-week module in the …

What Moves The Needle On Dfw Rates And Student Success In General Chemistry? A Quarter-Century Perspective, Vijay Vyas, Scott A. Reid

Chemistry Faculty Research and Publications

Second-term general chemistry is a key gateway course at our institution for a variety of STEM (Science, Technology, Engineering, and Mathematics) majors. Herein, we examine data on DFW% (i.e., % of D and F grades and withdrawals) in our general chemistry courses over roughly a quarter-century period, focusing on sections taught by the authors. The data are discussed in light of changes in curriculum, pedagogy, and assessments, which included introduction of recitation sections, classroom response systems (clickers), and online homework, restructuring of course content into a modular format, followed by a redesign of the course modules along an anchoring concepts …

Enhancing Motor Imagery Decoding Via Transfer Learning, Olawunmi George, Sarthak Dabas, Abdur Sikder, Roger Smith, Praveen Madiraju, Nasim Yahyasoltani, Sheikh Iqbal Ahamed

Computer Science Faculty Research and Publications

Motor imagery (MI) is arguably one of the most common brain–computer interface (BCI) paradigms. The decoding process, in many cases, involves the use of small amounts of data gathered over a period. The decoding performance might therefore be limited, due to the size of available data. Also, the non-stationarity of signals across sessions and subjects can pose a challenge to effective decoding. To solve these challenges, transfer learning is proposed as the suitable approach, which could yield optimal performance even with small amounts of data and handle the non-stationarity of signals with adaptation. It has been applied across domains and …

Reversible Dioxygen Binding To Co(Ii) Complexes With Noninnocent Ligands, Praveen Kumar, Laxmi Devkota, Maximilian C. Casey, Anne A. Fischer, Sergey V. Lindeman, Adam T. Fiedler

Chemistry Faculty Research and Publications

A series of mononuclear Co(II) complexes with noninnocent (redox-active) ligands are prepared that exhibit metal–ligand cooperativity during the reversible binding of O₂. The complexes have the general formula, [Co^II(L^S,N)(Tp^R2)] (R = Me, Ph), where L^S,N is a bidentate o-aminothiophenolate and Tp^R2 is a hydrotris(pyrazol-1-yl)borate scorpionate with R-substituents at the 3- and 5-positions. Exposure to O₂ at room temperature results in one-electron oxidation and deprotonation of L^S,N. The oxidized derivatives possess substantial “singlet diradical” character arising from antiferromagnetic coupling between an iminothiosemiquinonate (ITSQ^•–) …

Mixed Quantum/Classical Theory For Collisional Quenching Of Pahs In The Interstellar Media, Bikramaditya Mandal, Carolin Joy, Alexander Semenov, Dmitri Babikov

Chemistry Faculty Research and Publications

A computationally affordable methodology is developed to predict cross sections and rate coefficients for collisional quenching and excitation of large molecules in space, such as PAHs. Mixed quantum/classical theory of inelastic scattering (MQCT) is applied, in which quantum state-to-state transitions between the internal states of the molecule are described using a time-dependent Schrodinger equation, while the scattering of collision partners is described classically using mean-field trajectories. To boost the numerical performance even further, a decoupling scheme for the equations of motion and a Monte Carlo sampling of the initial conditions are implemented. The method is applied to compute cross sections …

Gray Counters For Non-Volatile Memories, Arockia David Roy Kulandai, John Rose, Thomas Schwarz

Computer Science Faculty Research and Publications

New technologies for non-volatile memories combine the speed and byte addressability of current memory technologies with the low cost, density, and non-volatility of current storage technologies. They use energy only when writing or reading data. While some newer technologies have practically unlimited endurance, others, such as Phase Change Memory do not. However, this limited endurance surpasses that of solid state drives by several orders of magnitude. They can be integrated into the current memory storage hierarchy as a replacement for DRAM. To manage limited endurance, age-based wear leveling divides the memory into pages and counts the number of writes to …

Emerging Technologies, Evolving Threats: Next-Generation Security Challenges, Tamara Bonaci, Katina Michael, Pablo Rivas, Lindsay J. Roberston, Michael Zimmer

Computer Science Faculty Research and Publications

Security is a fundamental human requirement. We desire the security of our person against injury, security of our capability to provide for our families, security of income linked to needs (food, water, clothing, and shelter), and much more. Most also hope for security of a way of life that is fulfilling and pleasant and peaceful [1] . In 2003, Alkire [2] defined “human security” as: “[t]he objective … to safeguard the vital core of all human lives from critical pervasive threats, in a way that is consistent with long-term human fulfillment.” Today most of the world’s population is highly dependent, …

Effect Of Ligands And Their Removal On The Au Nanoparticle-Catalyzed Reduction Of 4-Nitrophenol, Nicholas Langer, Ofer Kedem

Chemistry Faculty Research and Publications

The catalytic activity of gold nanoparticles (Au NPs) is strongly affected by the organic ligands coating them, which afford colloidal stability and are most commonly attached during the synthesis of the Au NPs. However, different ligands also produce Au NPs of different sizes and morphologies, complicating the study of the impact of the ligands themselves. Alternatively, postsynthetic ligand exchange risks incomplete exchanges and a mixed ligand shell, as well as colloidal instability. Here, Au NPs are immobilized on glass supports to afford truly ligand-free, solvent-stable Au nanoislands (NIs). The catalytic activity of Au NIs, uncoated and coated with a variety …

Enantioselective Synthesis Of Enantioisotopomers With Quantitative Chiral Analysis By Chiral Tag Rotational Spectroscopy, Mitchell D. Mills, Reilly E. Sonstrom, Zoua Pa Vang, Justin L. Neill, Haley N. Scolati, Channing T. West, Brooks H. Pate, Joseph R. Clark

Chemistry Faculty Research and Publications

Fundamental to the synthesis of enantioenriched chiral molecules is the ability to assign absolute configuration at each stereogenic center, and to determine the enantiomeric excess for each compound. While determination of enantiomeric excess and absolute configuration is often considered routine in many facets of asymmetric synthesis, the same determinations for enantioisotopomers remains a formidable challenge. Here, we report the first highly enantioselective metal-catalyzed synthesis of enantioisotopomers that are chiral by virtue of deuterium substitution along with the first general spectroscopic technique for assignment of the absolute configuration and quantitative determination of the enantiomeric excess of isotopically chiral molecules. Chiral tag …

Data Augmentation Strategies For Eeg-Based Motor Imagery Decoding, Olawunmi George, Roger Smith, Praveen Madiraju, Nasim Yahyasoltani, Sheikh Iqbal Ahamed

Computer Science Faculty Research and Publications

The wide use of motor imagery as a paradigm for brain-computer interfacing (BCI) points to its characteristic ability to generate discriminatory signals for communication and control. In recent times, deep learning techniques have increasingly been explored, in motor imagery decoding. While deep learning techniques are promising, a major challenge limiting their wide adoption is the amount of data available for decoding. To combat this challenge, data augmentation can be performed, to enhance decoding performance. In this study, we performed data augmentation by synthesizing motor imagery (MI) electroencephalography (EEG) trials, following six approaches. Data generated using these methods were evaluated based …

Uv- And Visible-Light Photopatterning Of Molecular Gradients Using The Thiol–Yne Click Reaction, Mark Mitmoen, Ofer Kedem

Chemistry Faculty Research and Publications

The rational design of chemical coatings is used to control surface interactions with small molecules, biomolecules, nanoparticles, and liquids as well as optical and other properties. Specifically, micropatterned surface coatings have been used in a wide variety of applications, including biosensing, cell growth assays, multiplexed biomolecule interaction arrays, and responsive surfaces. Here, a maskless photopatterning process is studied, using the photocatalyzed thiol–yne “click” reaction to create both binary and gradient patterns on thiolated surfaces. Nearly defect-free patterns are produced by first coating glass surfaces with mercaptopropylsilatrane, a silanizing agent that forms smoother self-assembled monolayers than the commonly used 3-mercaptopropyltrimethoxysilane. Photopatterning …

Context-Aware Graph-Based Self-Supervised Learning Of Whole Slide Images, Milam Aryal, Nasim Yahyasoltani

Computer Science Faculty Research and Publications

The gigapixel resolution of a single whole slide image (WSI), and the lack of huge annotated datasets needed for computational pathology, makes cancer diagnosis and grading with WSIs a challenging task. Moreover, downsampling of WSIs might result in loss of information critical for cancer diagnosis. Motivated by the fact that context such as topological structures in the tumor environment may contain critical information in cancer grading and diagnosis, a novel two-stage learning approach is proposed. Self-supervised learning is applied to improve training through unlabled data and graph convolutional network (GCN) is deployed to incorporate context from tumor and surrounding tissues. …

Highly Regioselective Copper-Catalyzed Transfer Hydrodeuteration Of Unactivated Terminal Alkenes, Albert Reyes, Emanuel Rivera Torres, Zoua Pa Vang, Joseph R. Clark

Chemistry Faculty Research and Publications

Catalytic transfer hydrodeuteration of unactivated alkenes is challenging because of the requirement that similar hydrogen and deuterium undergo selective insertion across a π-bond. We now report a highly regioselective catalytic transfer hydrodeuteration of unactivated terminal alkenes across a variety of heteroatom- or heterocycle-containing substrates. The base-metal-catalyzed reaction is also demonstrated on two complex natural products. Reaction studies indicate modular conditions that can also be extended to perform either an alkene transfer hydrogenation or transfer deuteration.

Environmentalism In J.R.R. Tolkien's Lord Of The Rings, Sophie Butler

4610 English: Individual Authors: J.R.R. Tolkien

The theme of environmentalism within Tolkien’s Lord of the Rings trilogy, while sometimes underlying, is an ever-present background to the characters and actions of Middle-Earth.The hero’s movements through nature contrasted with the criminal destruction of nature by the villains presents two clear perspectives about the treatment of nature, but Tolkien also inserts his perspective through the inclusion of Tree characters, like Ents. Trees and tree characters are an essential part of Tolkien's legendarium that help to illuminate the author's claims about environmentalism and the impacts of progress on the world. How characters interact with nature inform their ethics and point …

Molecular Dynamics On Quantum Annealers, Igor Gaidai, Dmitri Babikov, Alexander Teplukhin, Brian K. Kendrick, Susan M. Mniszewski, Yu Zhang, Sergei Tretiak, Pavel A. Dub

Chemistry Faculty Research and Publications

In this work we demonstrate a practical prospect of using quantum annealers for simulation of molecular dynamics. A methodology developed for this goal, dubbed Quantum Differential Equations (QDE), is applied to propagate classical trajectories for the vibration of the hydrogen molecule in several regimes: nearly harmonic, highly anharmonic, and dissociative motion. The results obtained using the D-Wave 2000Q quantum annealer are all consistent and quickly converge to the analytical reference solution. Several alternative strategies for such calculations are explored and it was found that the most accurate results and the best efficiency are obtained by combining the quantum annealer with …

Privacy Concerns With Using Public Data For Suicide Risk Prediction Algorithms: A Public Opinion Survey Of Contextual Appropriateness, Michael Zimmer, Sarah Logan

Computer Science Faculty Research and Publications

Purpose

Existing algorithms for predicting suicide risk rely solely on data from electronic health records, but such models could be improved through the incorporation of publicly available socioeconomic data – such as financial, legal, life event and sociodemographic data. The purpose of this study is to understand the complex ethical and privacy implications of incorporating sociodemographic data within the health context. This paper presents results from a survey exploring what the general public’s knowledge and concerns are about such publicly available data and the appropriateness of using it in suicide risk prediction algorithms.

Design/methodology/approach

A survey was developed to measure …

Accelerating Spatial Autocorrelation Computation With Parallelization, Vectorization And Memory Access Optimization, Anmol Paudel, Satish Puri

Computer Science Faculty Research and Publications

No abstract provided.

A Novel Framework For Mixed Reality–Based Control Of Collaborative Robot: Development Study, Md. Tanzil Shahria, Md. Samiul Haque Sunny, Md. Ishrak Islam Zarif, Md. Mahafuzur Rahaman Khan, Preet Parag Modi, Sheikh Iqbal Ahamed, Mohammad H. Rahman

Computer Science Faculty Research and Publications

Background:

Applications of robotics in daily life are becoming essential by creating new possibilities in different fields, especially in the collaborative environment. The potentials of collaborative robots are tremendous as they can work in the same workspace as humans. A framework employing a top-notch technology for collaborative robots will surely be worthwhile for further research.

Objective:

This study aims to present the development of a novel framework for the collaborative robot using mixed reality.

Methods:

The framework uses Unity and Unity Hub as a cross-platform gaming engine and project management tool to design the mixed reality interface and digital twin. …

Guest Editorial: Introduction To Aoir 2021 Papers On Emerging Ethical Practices And Platform Challenges, Michael Zimmer

Computer Science Faculty Research and Publications

No abstract provided.

Functional Singular Spectrum Analysis, Hossein Haghbin, Seyed Morteza Najibi, Rahim Mahmoudvand, Jordan Trinka, Mehdi Maadooliat

Mathematical and Statistical Science Faculty Research and Publications

In this paper, we develop a new extension of the singular spectrum analysis (SSA) called functional SSA to analyze functional time series. The new methodology is constructed by integrating ideas from functional data analysis and univariate SSA. Specifically, we introduce a trajectory operator in the functional world, which is equivalent to the trajectory matrix in the regular SSA. In the regular SSA, one needs to obtain the singular value decomposition (SVD) of the trajectory matrix to decompose a given time series. Since there is no procedure to extract the functional SVD (fSVD) of the trajectory operator, we introduce a computationally …

Triple Oxygen Isotope Constraints On Atmospheric O2 And Biological Productivity During The Mid-Proterozoic, Peng Liu, Jingjin Liu, Aoshaung Ji, Christopher T. Reinhard, Noah J. Planavsky, Dmitri Babikov, Raymond G. Najjar, James F. Kasting

Chemistry Faculty Research and Publications

Reconstructing the history of biological productivity and atmospheric oxygen partial pressure (pO₂) is a fundamental goal of geobiology. Recently, the mass-independent fractionation of oxygen isotopes (O-MIF) has been used as a tool for estimating pO₂ and productivity during the Proterozoic. O-MIF, reported as Δ′¹⁷O, is produced during the formation of ozone and destroyed by isotopic exchange with water by biological and chemical processes. Atmospheric O-MIF can be preserved in the geologic record when pyrite (FeS₂) is oxidized during weathering, and the sulfur is redeposited as sulfate. Here, sedimentary sulfates from …

2d Covalent Organic Frameworks With An Incorporated Manganese Complex For Light Driven Carbon Dioxide Reduction, Denan Wang, Daniel Streater, Yun Peng, Jier Huang

Chemistry Faculty Research and Publications

Covalent organic frameworks (COFs) have emerged as a novel class of crystalline porous photocatalytic materials due to their unique properties such as large surface area, tunable porosity, and rigid structure. In this work, we report the direct incorporation of a manganese CO₂ molecular catalyst (MC) into COFs (Mn−TTA-COF) and the evaluation of its capability as photocatalyst for visible light driven CO₂ reduction to form CO. We found that the photocatalytic activity of Mn−TTA-COF is quite low, which mainly results from the elimination of the CO ligand in the Mn MC upon light illumination, rendering its short duration in …

Identification Of An Intermediate Species Along The Nitrile Hydratase Reaction Pathway By Epr Spectroscopy, Wasantha Lankathilaka Karunagala Pathiranage, Natalie Gumataotao, Adam T. Fiedler, Richard C. Holz, Brian Bennett

Physics Faculty Research and Publications

A new method to trap catalytic intermediate species was employed with Fe-type nitrile hydratase from Rhodococcus equi TG328-2 (ReNHase). ReNHase was incubated with substrates in a 23% (w/w) NaCl/H₂O eutectic system that remained liquid at −20 °C, thereby permitting the observation of transient species that were present at electron paramagnetic resonance (EPR)-detectable levels in samples frozen while in the steady state. Fe^III-EPR signals from the resting enzyme were unaffected by the presence of 23% NaCl, and the catalytic activity was ∼55% that in the absence of NaCl at the optimum pH of 7.5. …

Examination Of The Catalytic Role Of The Axial Cystine Ligand In The Co-Type Nitrile Hydratase From Pseudonocardia Thermophila Jcm 3095, Irene Anyango Ogutu, Martin St. Maurice, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

The strictly conserved αSer162 residue in the Co-type nitrile hydratase from Pseudonocardia thermophila JCM 3095 (PtNHase), which forms a hydrogen bond to the axial αCys108-S atom, was mutated into an Ala residue. The αSer162Ala yielded two different protein species: one was the apoform (αSer^A) that exhibited no observable activity, and the second (αSer^B) contained its full complement of cobalt ions and was active with a k_cat value of 63 ± 3 s⁻¹ towards acrylonitrile at pH 7.5. The X-ray crystal structure of was determined at 1.85 Å resolution and contained no detectable …

Spectrumsdt: A Program For Parallel Calculation Of Coupled Rotational-Vibrational Energies And Lifetimes Of Bound States And Scattering Resonances In Triatomic Systems, Igor Gayday, Alexander Teplukhin, Jonathan Moussa, Dmitri Babikov

Chemistry Faculty Research and Publications

We present SpectrumSDT – a program for calculations of energies and lifetimes of bound rotational-vibrational states below and scattering resonances above the dissociation threshold on a global potential energy surface of a triatomic system, which may include stable molecules, weekly-bound van-der-Waals complexes, and unbound atom + diatom scattering systems. Large-amplitude vibrational motion is treated explicitly using hyper-spherical coordinates. Three options for the rotational-vibrational interaction are supported: uncoupled (symmetric top rotor), partially coupled (to include interaction between several nearest states only) and full-coupled (vibrating asymmetric-top rotor). In addition to energies and lifetimes, SpectrumSDT is able to integrate ro-vibrational wave functions over …

Workers’ Attitudes Toward Increased Surveillance During And After The Covid-19 Pandemic, Jessica Vitak, Michael Zimmer

Computer Science Faculty Research and Publications

Amid the Covid-19 pandemic, the transition of many offices to remote work has led to new ways for employers to track workers’ movements, behavior, and productivity. Through their SSRC-funded research, Jessica Vitak and Michael Zimmer surveyed remote workers in the US about perceptions of current workplace monitoring practices. They argue that worker concerns about reductions in privacy and independence at work might have negative outcomes on worker productivity, satisfaction, and well-being.

Dissecting Monomer-Dimer Equilibrium Of An Rnase P Protein Provides Insight Into The Synergistic Flexibility Of 5’ Leader Pre-Trna Recognition, Danyun Zeng, Ainur Abzhanova, Benjamin P. Brown, Nicholas J. Reiter

Chemistry Faculty Research and Publications

Ribonuclease P (RNase P) is a universal RNA-protein endonuclease that catalyzes 5’ precursor-tRNA (ptRNA) processing. The RNase P RNA plays the catalytic role in ptRNA processing; however, the RNase P protein is required for catalysis in vivo and interacts with the 5’ leader sequence. A single P RNA and a P protein form the functional RNase P holoenzyme yet dimeric forms of bacterial RNase P can interact with non-tRNA substrates and influence bacterial cell growth. Oligomeric forms of the P protein can also occur in vitro and occlude the 5’ leader ptRNA binding interface, presenting a challenge in accurately defining …

Electronic Structures And Spectroscopic Signatures Of Diiron Intermediates Generated By O2 Activation Of Nonheme Iron(Ii)–Thiolate Complexes, Danushka M. Ekanayake, Dao Pham, Andrew L. Probst, Joshua R. Miller, Cordina V. Popescu, Adam T. Fiedler

Chemistry Faculty Research and Publications

The activation of O₂ at thiolate–ligated iron(II) sites is essential to the function of numerous metalloenzymes and synthetic catalysts. Iron–thiolate bonds in the active sites of nonheme iron enzymes arise from either coordination of an endogenous cysteinate residue or binding of a deprotonated thiol-containing substrate. Examples of the latter include sulfoxide synthases, such as EgtB and OvoA, that utilize O₂ to catalyze tandem S–C bond formation and S-oxygenation steps in thiohistidine biosyntheses. We recently reported the preparation of two mononuclear nonheme iron–thiolate complexes (1 and 2) that serve as structural active-site models of substrate-bound EgtB …

Covalent Immobilization Of Molecular Complexes On Metal-Organic Frameworks Towards Robust And Highly Efficient Heterogeneous Water Oxidation Catalysts, Xiangming Liang, Sizhou Yang, Junyi Yang, Wanjun Sun, Xiangyang Li, Baochun Ma, Jier Huang, Jiangwei Zhang, Lele Duan, Yong Ding

Chemistry Faculty Research and Publications

The major challenges to practical implementation of efficient noble metal based molecular water oxidation catalysts are their stability and recycle ability. Herein, noble metal Ru based molecular water oxidation catalysts were covalently anchored in MOFs through “amide bond” as bridges, which leads to the formation of high-efficiency and robust heterogeneous catalysts for water oxidation reaction. We show that the efficiency for Ce^IV-driven water oxidation was significantly enhanced by 120 times when the Ru molecules were immobilized on the frameworks of MIL-101(Cr). The relationship between recycle stability and the structure of the Ru complexes covalently anchored in MOFs was …

Catalytic Transfer Deuteration And Hydrodeuteration: Emerging Techniques To Selectively Transform Alkenes And Alkynes To Deuterated Alkanes, Zoua Pa Vang, Samuel J. Hintzsche, Joseph R. Clark

Chemistry Faculty Research and Publications

Increasing demand for deuterium-labeled organic molecules has spurred a renewed interest in selective methods for deuterium installation. Catalytic transfer deuteration and transfer hydrodeuteration are emerging as powerful techniques for the selective incorporation of deuterium into small molecules. These reactions not only obviate the use of D₂ gas and pressurized reaction setups but provide new opportunities for selectively installing deuterium into small molecules. Commercial or readily synthesized deuterium donors are typically employed as easy-to-handle reagents for transfer deuteration and hydrodeuteration reactions. In this minireview, recent advances in the catalytic transfer deuteration and hydrodeuteration of alkenes and alkynes for the selective …