Physical Sciences and Mathematics Commons^™

Self-Inductance And Magnetic Flux, Diego Castano, Teresa M. Castano

Chemistry and Physics Faculty Articles

The canonical equation for self-inductance involving magnetic flux is examined, and a more general form is presented that can be applied to continuous current distributions. We attempt to clarify and extend the use of the standard equation by recasting it in its more versatile form.

Roundup And Glyphosate’S Impact On Gaba To Elicit Extended Proconvulsant Behavior In Caenorhabditis Elegans, Akshay Naraine, Rebecca Aker, Isis Sweeney, Meghan Kalvey, Alexis Surtel, Venkatesh Shanbhag, Ken Dawson-Scully

Chemistry and Physics Faculty Articles

As 3 billion pounds of herbicides are sprayed over farmlands every year, it is essential to advance our understanding how pesticides may influence neurological health and physiology of both humans and other animals. Studies are often one-dimensional as the majority examine glyphosate by itself. Farmers and the public use commercial products, like Roundup, containing a myriad of chemicals in addition to glyphosate. Currently, there are no neurological targets proposed for glyphosate and little comparison to Roundup. To investigate this, we compared how glyphosate and Roundup affect convulsant behavior in C. elegans and found that glyphosate and Roundup increased seizure-like behavior. …

Catalog Of Edge-On Galaxies Using The Pan-Starrs1 Survey Data, Dimitry I. Makarov, S. Savchenko, Alexander V. Mosenkov, Dmitry V. Bizyaev, Vladimir P. Reshetnikov, Alexandra V. Antipova, I. Tikhonenko, P. Usachev, S. Borisov, L. Makarova, Stefan Kautsch, A. Marchuk, E. Rub Edukov, M. Skryabina, P. Smirnova

Chemistry and Physics Faculty Articles

We have created a catalog of edge-on galaxies based on the publicly available DR2 data from the Pan-STARRS survey. The intensive use of an artificial neural network has significantly improved the quality of candidate selection. The catalog provides homogeneous information on astrometry, photometry, and non-parametric morphological statistics for 16551 edge-on galaxies. Our catalog is intended for studying the three-dimensional structure of galaxies with different morphologies and the scaling relations for disks and bulges.

Morphology Transformation Of Foldamer Assemblies Triggered By Single Oxygen Atom On Critical Residue Switch, Byung-Chang Oh, Eunyoung Yoon, Jintaek Gong, Jaewook Kim, Russell W. Driver, Yongjun Kim, Woo Youn Kim, Hee-Seung Lee

Chemistry and Physics Faculty Articles

The synthesis of morphologically well-defined peptidic materials via self-assembly is challenging but demanding for biocompatible functional materials. Moreover, switching morphology from a given shape to other predictable forms by molecular modification of the identical building block is an even more complicated subject because the self-assembly of flexible peptides is prone to diverge upon subtle structural change. To accomplish controllable morphology transformation, systematic self-assembly studies are performed using congener short β-peptide foldamers to find a minimal structural change that alters the self-assembled morphology. Introduction of oxygen-containing β-amino acid (ATFC) for subtle electronic perturbation on hydrophobic foldamer induces a previously inaccessible solid-state …

Motif Wfyy Of Human Primpol Is Crucial To Stabilize The Incoming 3′-Nucleotide During Replication Fork Restart, Patricia R. Calvo, María I. Martínez-Jiménez, Marcos Díaz, Gorazd Stojkovic, Kazutoshi Kasho, Susana Guerra, Sjoerd Wanrooij, Juan Méndez, Luis Blanco

Chemistry and Physics Faculty Articles

PrimPol is the second primase in human cells, the first with the ability to start DNA chains with dNTPs. PrimPol contributes to DNA damage tolerance by restarting DNA synthesis beyond stalling lesions, acting as a TLS primase. Multiple alignment of eukaryotic PrimPols allowed us to identify a highly conserved motif, WxxY near the invariant motif A, which contains two active site metal ligands in all members of the archeo-eukaryotic primase (AEP) superfamily. In vivo and in vitro analysis of single variants of the WFYY motif of human PrimPol demonstrated that the invariant Trp⁸⁷ and Tyr⁹⁰ residues are essential …

Visualizing Amino Acid Substitutions In A Physicochemical Vector Space, Louis R. Nemzer

Chemistry and Physics Faculty Articles

A three-dimensional representation of the twenty proteinogenic amino acids in a physicochemical space is presented. Vectors corresponding to amino acid substitutions are classified based on whether they are accessible via a single-nucleotide mutation. It is shown that the standard genetic code establishes a “choice architecture” that permits nearly independent tuning of the properties related with size and those related with hydrophobicity. This work sheds light on the metarules of evolvability that may have shaped the standard genetic code to increase the probability that adaptive point mutations will be generated. An illustration of the usefulness of visualizing amino acid substitutions in …

Experimental Evidence That Metapopulation Structure Can Accelerate Adaptive Evolution, Partha Pratim Chakraborty, Louis R. Nemzer, Rees Kassen

Chemistry and Physics Faculty Articles

Whether the spatial arrangement of a population influences adaptive evolution has been a long-standing question in population genetics. In contrast to standard population genetic models, evolutionary graph theory (EGT) predicts certain topologies amplify (increase) the probability that a beneficial mutation will spread in the population relative to a well-mixed population. Here, we test these predictions empirically by tracking the fixation dynamics of an antibiotic resistant mutant under positive selection as it spreads through networks of different topologies both in vitro and in silico. We show that star-like topologies involving bi-directional dispersal between a central hub and peripheral leaves can …

The Pedagogical Representation Of Mass Functions With Lego And Their Origin, Stefan Kautsch

Chemistry and Physics Faculty Articles

We promote the teaching of mass functions as an integral part of an interdisciplinary science education. Mass functions characterize the frequency distributions of objects with different masses on all cosmic scales. We intend to enhance experiential learning of this concept with a creative LEGO brick experiment for a diverse student audience. To our surprise, the LEGO mass function is not only qualitatively but also quantitatively comparable to mass functions found across the universe. We also discuss the relation between gravitation and mass distributions as a possible explanation for the continuity of the universal mass function.

Effects Of Nitrogen Depletion On The Biosorption Capacities Of Neochloris Minuta And Neochloris Alveolaris For Five Heavy Metals, Dimitri Giarikos, Jessica Brown, Reza Razeghifard, Duy Vo, Ammy Castillo, Nikhil Nagabandi, Justin Gaffney, Miriam Zelden, Anna Antakshinova, Sara Rodriguez, Safiyah Muhammad

Chemistry and Physics Faculty Articles

Neochloris minuta and Neochloris alveolaris grown in nitrogen-rich (+ N) and nitrogen-depleted (-N) media were tested for their heavy metal maximum biosorption capacities (q_max) and adsorption percent efficiencies (R%). By removing nitrogen from the growth media, both algal species showed an increase in their lipid content and a decrease in their protein content. Langmuir and Freundlich adsorption isotherms were used to determine the q_max and adsorption efficiencies of the + N and −N algae in the recovery of Pb²⁺, Cd²⁺, Zn²⁺, Cu²⁺, and Ni²⁺. When comparing the …

Critical And Ictal Phases In Simulated Eeg Signals On A Small-World Network, Louis R. Nemzer, Gary D. Cravens, Robert M. Worth, Francis Motta, Andon Placzek, Victor Castro, Jennie Q. Lou

Chemistry and Physics Faculty Articles

Healthy brain function is marked by neuronal network dynamics at or near the critical phase, which separates regimes of instability and stasis. A failure to remain at this critical point can lead to neurological disorders such as epilepsy, which is associated with pathological synchronization of neuronal oscillations. Using full Hodgkin-Huxley (HH) simulations on a Small-World Network, we are able to generate synthetic electroencephalogram (EEG) signals with intervals corresponding to seizure (ictal) or non-seizure (interictal) states that can occur based on the hyperexcitability of the artificial neurons and the strength and topology of the synaptic connections between them. These interictal simulations …

Stay Calm And Focus On The Learning Outcomes: Tools For Taking Biophysical Chemistry Online, Maria Ballester, Brian L. Van Hoozen Jr., Arthur Sikora

Chemistry and Physics Faculty Articles

Course specific learning outcomes are an important tool to define the scope of a course and can be very helpful when designing experiments and assessments. With slight modification, these learning outcomes can serve as a guide when transitioning to the distance learning format especially in courses with a traditional lab. Here we present such an example for the biophysical chemistry course.

Antagonistic Roles Of Grk2 And Grk5 In Cardiac Aldosterone Signaling Reveal Grk5-Mediated Cardioprotection Via Mineralocorticoid Receptor Inhibition, Jennifer Maning, Katie Anne Mccrink, Celina M. Pollard, Victoria Desimine, Jennifer Ghandour, Arianna Perez, Natalie Cora, Krysten E. Ferraino, Barbara Parker, Ava Brill, Beatrix Aukszi, Anastasios Lymperopoulos

Chemistry and Physics Faculty Articles

Aldosterone (Aldo), when overproduced, is a cardiotoxic hormone underlying heart failure and hypertension. Aldo exerts damaging effects via the mineralocorticoid receptor (MR) but also activates the antiapoptotic G protein-coupled estrogen receptor (GPER) in the heart. G protein-coupled receptor (GPCR)-kinase (GRK)-2 and -5 are the most abundant cardiac GRKs and phosphorylate GPCRs as well as non-GPCR substrates. Herein, we investigated whether they phosphorylate and regulate cardiac MR and GPER. To this end, we used the cardiomyocyte cell line H9c2 and adult rat ventricular myocytes (ARVMs), in which we manipulated GRK5 protein levels via clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 and …

The Place Of Arbs In Heart Failure Therapy: Is Aldosterone Suppression The Key?, Uma Markan, Samhitha Pasupuleti, Celina M. Pollard, Arianna Perez Bhs Student, Beatrix Aukszi, Anastasios Lymperopoulos

Chemistry and Physics Faculty Articles

Since the launch of the first orally available angiotensin II (AngII) type 1 receptor (AT₁R) blocker (ARB) losartan (Cozaar) in the late 1990s, the class of ARBs (or ‘sartans’, short for Angiotensin-RecepTor-ANtagonistS) quickly expanded to include candesartan, eprosartan, irbesartan, valsartan, telmisartan, and olmesartan. All ARBs have high affinity for the AT₁ receptor, expressed in various tissues, including smooth muscle cells, heart, kidney, and brain. Since activation of AT₁R, the target of these drugs, leads, among other effects, to vascular smooth muscle cell growth, proliferation and contraction, activation of fibroblasts, cardiac hypertrophy, aldosterone secretion from the …

A Practical, Quantitative Electrostatics Experiment, Bryan K. Armentrout, Diego Castano

Chemistry and Physics Faculty Articles

An electrostatics experiment is presented that is practical, affordable, and quantitative. The equipment required is readily available and relatively inexpensive. The experiment relies on the electrostatic induction that results from a charged insulative plate in proximity to a conductive sphere. The experiment yields accessible results (a) under a variety of environmental conditions and results that (b) allow for quantitative analyses. These two characteristics distinguish it from most other simple electrostatics experiments. It is intended for college introductory physics students.

Application Of Click Chemistry In The Development Of Peptide Based Hiv Fusion Inhibitors, Mukesh Madan Mudgal, Nagaraju Birudukota

Chemistry and Physics Faculty Articles

Human Immunodeficiency Virus (HIV) continues to be a major global public health issue. Inhibition of HIV envelope fusion with the CD4 cell membrane prevents the entry of HIV into the CD4 cells providing a novel approach to the treatment of HIV infection. Thus, interference in the fusion of the virus with the co-receptor substrate appears to be a specific and potential way to fight HIV infection and replication. Applications of click chemistry are spreading in the field of drug discovery and it became a powerful tool for the synthesis of medicinally important compounds.

Remarkably, the Cu (I)-Catalyzed Azide-Alkyne Cycloaddition (CuAAC) …

The Physics Of Moving Bodies, Diego Castano

Chemistry and Physics Faculty Articles

An alternative theoretical development of Special Relativity is presented in which Electrodynamics is not invoked. In deriving the Lorentz transformation in this manner, the existence of a maximal speed for all physical phenomena stands out. The mass-energy relation is also derived without reference to light.

Un développement théorique alternative de la relativité restreinte est présenté dans lequel l’électrodynamique n’est pas invoquée. En dérivant la transformation de Lorentz de cette manière, l’existence d’une vitesse maximale pour tous les phénomènes physiques ressort. La relation masse-énergie est également dérivée sans référence à la lumière.

Applications Of Click Chemistry In The Development Of Hiv Protease Inhibitors, Mukesh Madan Mudgal, Nagaraju Birudukota, Mayur A. Doke

Chemistry and Physics Faculty Articles

Acquired Immunodeficiency Syndrome (AIDS) has been devastating for millions of people around the world. Inhibition of the human immunodeficiency virus (HIV) protease is among the most important approaches for the therapeutic intervention in HIV infection. Since the discovery of the HIV-1 protease, this enzyme has been considered as a key target for the inhibition of viral replication. A large body of research has been done to develop an effective HIV-1 protease inhibitor. There are to date 10 HIV-1 protease inhibitor drugs approved by the Food and Drug Administration (FDA) that have improved the survival and quality of life of HIV …

Starch, Lipid, And Protein Accumulation In Nutrient-Stressed Microalgal Cells Studied Using Fourier Transform Infrared Microscopy, Gary Hastings, Jodian Thomas, Keillor Witt, Dimitri Giarikos, Reza Razeghifard

Chemistry and Physics Faculty Articles

Microalgae are fast growing organisms that can be used as feedstock for the production of biofuels. The metabolism of microalgae can be manipulated by exposing them to different environmental conditions for favoring the accumulation of lipids, carbohydrates or proteins. For example, a change in growth conditions can cause the accumulation of large amounts of lipids, representing an opportunity for biodiesel production. Monitoring changes in the composition of microalgal cells is therefore important in assessing new growth conditions. However, at present, most techniques are time consuming, invasive and expensive. Here we have used FTIR microscopy to quantify lipid, protein, and starch …

Developing Luminescent Lanthanide Coordination Polymers And Metal-Organic Frameworks For Bioimaging Applications, Aida Gonzalez, Xiu Mei-Chu, Kathryn A. Pitton, Ryan Crichton, Jeffrey D. Einkauf

Chemistry and Physics Faculty Articles

This study focuses on the solvothermal synthesis of two lanthanide-based coordination polymer/metal-organic framework systems assembled from 1,3,5-benzenetricarboxylic acid (BTC) in the nano-sized regime for use as bioimaging agents. These materials were synthesized using two different lanthanide ions, a luminescent center (Eu, Tb) for optical imaging purposes and Gd, whose magnetic properties are particularly beneficial in magnetic resonance imaging (MRI) as
a contrast agent. Together, these two features allow for multimodal imaging, useful in the study and diagnosis of disease. Under identical reaction conditions, two different compounds were formed upon changing the identity of the optically active lanthanide metal ion. Compound …

Angiotensin Receptor Blocker Drugs And Inhibition Of Adrenal Beta-Arrestin-1-Dependent Aldosterone Production: Implications For Heart Failure Therapy, Anastasios Lymperopoulos, Beatrix Aukszi

Chemistry and Physics Faculty Articles

Aldosterone mediates many of the physiological and pathophysiological/cardio-toxic effects of angiotensin II (AngII). Its synthesis and secretion from the zona glomerulosa cells of the adrenal cortex, elevated in chronic heart failure (HF), is induced by AngII type 1 receptors (AT1Rs). The AT1R is a G protein-coupled receptor, mainly coupling to Gq/11 proteins. However, it can also signal through β-arrestin-1 (βarr1) or -2 (βarr2), both of which mediate G protein-independent signaling. Over the past decade, a second, Gq/11 protein-independent but βarr1-dependent signaling pathway emanating from the adrenocortical AT1R and leading to aldosterone production has become appreciated. Thus, it became apparent that …

Does The Stellar Disc Flattening Depend On The Galaxy Type, A. V. Mosenkov, N. Ya. Sotnikova, V. P. Reshetnikov, D. V. Bizyaev, Stefan Kautsch

Chemistry and Physics Faculty Articles

We analyse the dependence of the stellar disc flatness on the galaxy morphological type using 2D decomposition of galaxies from the reliable subsample of the Edge-on Galaxies in SDSS catalogue. Combining these data with the retrieved models of the edge-on galaxies from the Two Micron All Sky Survey and the Spitzer Survey of Stellar Structure in Galaxies catalogue, we make the following conclusions.

1. The disc relative thickness z₀/h in the near- and mid-infrared passbands correlates weakly with morphological type and does not correlate with the bulge-to-total luminosity ratio B/T in all studied bands.

2. Applying a 1D photometric …

Preparation, Crystal Structure, Thermal Analysis, Scanning Electron Microscopy And Optical Band-Gaps Of Cu2gete4 And Cu2snte4 Alloys, Pedro Grima Gallardo, Ricardo Pena, Luis Nieves, Gustavo Marcano, Miguel Quintero, Ekadink Moreno, Jian-Han Zhang, Jacilynn A. Brant, Jennifer A. Aitken

Chemistry and Physics Faculty Articles

Polycrystalline samples (weight ~ 1g) of Cu ₂ GeTe ₄ and Cu ₂ SnTe ₄ alloys were prepared by the usual melt and anneal method and the products characterized by X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), Scanning Electron Microscopy (SEM) and Optical Diffuse Reflectance UV / VIS / NIR Spectroscopytechniques. It was found that: a) Cu ₂ GeTe ₄ and Cu ₂ SnTe ₄ crystallize in an orthorhombic structure (sg Imm2; N ^o44) with lattice parameters a = 5.9281 (4) Å, b = 4.2211 (6) Å, c = 12.645 (5) Å and a = 6.0375 (6) Å, b …

Glycosylation Modulates Melanoma Cell Α2Β1 And Α3Β1 Integrin Interactions With Type Iv Collagen, Maciej J. Stawikowski, Beatrix Aukszi, Roma Stawikowska, Mare Cudic, Gregg B. Fields

Chemistry and Physics Faculty Articles

Although type IV collagen is heavily glycosylated, the influence of this posttranslational modification on integrin binding has not been investigated. In the present study, galactosylated and non-galactosylated triple-helical peptides have been constructed containing the α1(IV)382-393 and α1(IV)531-543 sequences, which are binding sites for the α2β1 and α3β1 integrins, respectively. All peptides had triple-helical stabilities of 37 °C or greater. The galactosylation of Hyl393 in α1(IV)382-393 and Hyl540 and Hyl543 in α1(IV)531-543 had a dose dependent influence on melanoma cell adhesion which was much more pronounced in the case of α3β1 integrin binding. Molecular modeling indicated that galactosylation occurred on the …

The Catalog Of Edge-On Disk Galaxies From Sdss. I. The Catalog And The Structural Parameters Of Stellar Disks, D. V. Bizyaev, Stefan Kautsch, A. V. Mosenkov, V. P. Reshetnikov, N. Ya. Sotnikova, N. V. Yablokova

Chemistry and Physics Faculty Articles

We present a catalog of true edge-on disk galaxies automatically selected from the Seventh Data Release of the Sloan Digital Sky Survey (SDSS). A visual inspection of the g, r, and iimages of about 15,000 galaxies allowed us to split the initial sample of edge-on galaxy candidates into 4768 (31.8% of the initial sample) genuine edge-on galaxies, 8350 (55.7%) non-edge-on galaxies, and 1865 (12.5%) edge-on galaxies not suitable for simple automatic analysis because these objects either show signs of interaction and warps, or nearby bright stars project on it. We added more candidate galaxies from RFGC, EFIGI, …

Shared Mycobacterium Avium Genotypes Observed Among Unlinked Clinical And Environmental Isolates, M. Ashworth Dirac, Kris M. Weigel, Mitchell A. Yakrus, Annie L. Becker, Hui-Ling Chen, Gina Fridley, Arthur Sikora, Cate Speake, Elizabeth D. Hilborn, Stacy Pfaller, Gerard A. Cangelosi

Chemistry and Physics Faculty Articles

Our understanding of the sources of Mycobacterium avium infection is partially based on genotypic matching of pathogen isolates from cases and environmental sources. These approaches assume that genotypic identity is rare in isolates from unlinked cases or sources. To test this assumption, a high-resolution PCR-based genotyping approach, large-sequence polymorphism (LSP)-mycobacterial interspersed repetitive unit–variable-number tandem repeat (MIRU-VNTR), was selected and used to analyze clinical and environmental isolates of M. avium from geographically diverse sources. Among 127 clinical isolates from seven locations in North America, South America, and Europe, 42 genotypes were observed. Among 12 of these genotypes, matches were seen in …

Flexural Rigidity Measurements Of Biopolymers Using Gliding Assays, Douglas S. Martin, Lu Yu, Brian L. Van Hoozen Jr.

Chemistry and Physics Faculty Articles

Microtubules are cytoskeletal polymers which play a role in cell division, cell mechanics, and intracellular transport. Each of these functions requires microtubules that are stiff and straight enough to span a significant fraction of the cell diameter. As a result, the microtubule persistence length, a measure of stiffness, has been actively studied for the past two decades. Nonetheless, open questions remain: short microtubules are 10-50 times less stiff than long microtubules, and even long microtubules have measured persistence lengths which vary by an order of magnitude.

Here, we present a method to measure microtubule persistence length. The method is based …

Capturing Fleeting Intermediates In A Catalytic C-H Amination Reaction Cycle, Richard H. Perry, Thomas J. Cahill Iii, Jennifer L. Roizen, Justin Du Bois, Richard N. Zare

Chemistry and Physics Faculty Articles

We have applied an ambient ionization technique, desorption electrospray ionization MS, to identify transient reactive species of an archetypal C–H amination reaction catalyzed by a dirhodium tetracarboxylate complex. Using this analytical method, we have detected previously proposed short-lived reaction intermediates, including two nitrenoid complexes that differ in oxidation state. Our findings suggest that an Rh-nitrene oxidant can react with hydrocarbon substrates through a hydrogen atom abstraction pathway and raise the intriguing possibility that two catalytic C–H amination pathways may be operative in a typical bulk solution reaction. As highlighted by these results, desorption electrospray ionization MS should have broad applicability …

Anti-Neoplastic Activity Of Two Flavone Isomers Derived From Gnaphalium Elegans And Achyrocline Bogotensis, Christan M. Thomas, Robert C. Wood Iii, Jarrett E. Wyatt, Morgan H. Pendleton, Ruben D. Torrenegra, Oscar E. Rodriguez, Sam Harirforoosh, Maria Ballester, Janet Lightner, Koyamangalath Krishnan, Victoria P. Ramsauer

Chemistry and Physics Faculty Articles

Over 4000 flavonoids have been identified so far and among these, many are known to have antitumor activities. The basis of the relationships between chemical structures, type and position of substituent groups and the effects these compounds exert specifically on cancer cells are not completely elucidated. Here we report the differential cytotoxic effects of two flavone isomers on human cancer cells from breast (MCF7, SK-BR-3), colon (Caco-2, HCT116), pancreas (MIA PaCa, Panc 28), and prostate (PC3, LNCaP) that vary in differentiation status and tumorigenic potential. These flavones are derived from plants of the family Asteraceae, genera Gnaphalium and Achyrocline …

Benzo[1,2-B:4,5-B′]Dithio­Phene-4,8-Dione, Amanda L. Ramirez, Benny C. Chan, Daniel T. De Lill

Chemistry and Physics Faculty Articles

The title mol­ecule, C₁₀H₄O₂S₂, is situated on a crystallographic center of inversion. In the crystal, weak hydrogen bonding contributes to the packing of the mol­ecules.

Transient Ru-Methyl Formate Intermediates Generated With Bifunctional Transfer Hydrogenation Catalysts, Richard H. Perry, Kristen R. Brownell, Konstantin Chingin, Thomas J. Cahill Iii, Robert M. Waymouth, Richard N. Zare

Chemistry and Physics Faculty Articles

Desorption electrospray ionization (DESI) coupled to high-resolution Orbitrap mass spectrometry (MS) was used to study the reactivity of a (β-amino alcohol)(arene)RuCl transfer hydrogenation catalytic precursor in methanol (CH₃OH). By placing [(p-cymene)RuCl₂]₂ on a surface and spraying a solution of β-amino alcohol in methanol, two unique transient intermediates having lifetimes in the submillisecond to millisecond range were detected. These intermediates were identified as Ru (II) and Ru (IV) complexes incorporating methyl formate (HCOOCH₃). The Ru (IV) intermediate is not observed when the DESI spray solution is sparged with Ar gas, indicating that …