Chemistry Commons^™

The Impact Of Inter-Subunit Communication On F420h2:Nadp+ Oxidioreductase: A Kinetic Approach, Jamariya A. Howard

Chemistry & Biochemistry Dissertations - Archive

F₄₂₀H₂:NADP⁺ Oxidoreductase (Fno) catalyzes the reversible reduction of NADP⁺ to NADPH using reduced F₄₂₀ as the hydride donor. Both NADPH and the F₄₂₀ cofactor play significant roles in various metabolic pathways, including glycolysis and methanogenesis, particularly in methanogenic and sulfate-reducing archaea. These organisms play an essential role in global carbon cycling by converting carbon dioxide to methane through the methanogenic pathway, which is directly tied to energy production. This thesis investigates the hydride transfer mechanism of Fno from the extreme thermophile Archaeoglobus fulgidus, using fluorescence binding, steady-state and pre steady-state kinetics.

Chapter 1 outlines the structural and spectral characteristics …

Reducing Friction In Machine Oil Via Cesium-Hybridized Graphene Oxide Quantum Dot Additives, Islam Gomaa, Sherief Elsoudy, Maryam Galal, Ahmed Azim

Nanotechnology Research Centre

Friction and wear are among the most common causes of energy loss and component failure in mechanical systems, accounting for around 20–30% of total global energy consumption. Conventional lubricants fail to provide consistent performance in harsh conditions due to inadequate additive dispersion, agglomeration, and restricted surface reactivity. Recent advances in nanomaterial-based lubricants have shown promise, but it remains difficult to achieve significant friction and wear reduction at low additive concentrations while preserving stability. In this study, we synthesized and tested cesium-hybridized graphene oxide quantum dots (Cs-GOQDs) as novel lubricant additives. When incorporated into machine oil at 0.1 wt%, Cs-GOQDs reduced …

What Amino Acid Residue Is Responsible For The Interaction Of Atg11 With Its Autophagy Partner Atg9?, Patricia Omoyemwen Woghiren

Senior Honors Theses and Projects

Macroautophagy is a cellular function that involves the formation of a double membrane vesicle that isolates and transports cellular materials to the vacuole or lysosome for degradation and recycling. It is divided into selective and non-selective macroautophagy. Atg11 and Atg9 are two key proteins involved in selective macroautophagy, and their interaction is critical for selective macroautophagy. Specific residues on Atg9 critical for Atg11 binding have been identified, but similar residues on Atg11 have not been identified. The aim of my research was to identify a specific residue critical for Atg11’s interaction with Atg9. To this end, we carried out Yeast-twohybrid …

Ex Vivo Single-Molecule Analysis Of Ryanodine Receptor 2 Assembly In Cardiac And Neuronal Tissue, Qianye Yin, Christopher I. Richards

Chemistry Faculty Publications

Understanding receptor assembly is critical for elucidating the mechanisms underlying their function and regulation in physiological processes. While traditional in vitro single-molecule studies rely on isolating proteins from heterologous expression systems, they often fail to capture the in vivo physiological complexity involved in the organization and assembly of cell surface proteins. This protocol employs Total Internal Reflection Fluorescence Microscopy (TIRFM) to study GFP-tagged Ryanodine Receptor 2 (RyR2) molecules encapsulated within nanoscale vesicles. These vesicles, generated from organs rapidly extracted from the animal, effectively provide a snapshot of the receptor's assembly state at the time of extraction, enabling detailed analysis of …

Complexometric Titration Of Terbium(Iii) Compounds: An Analytical Blast From The Past Gives Purity Assurance When Modern Instruments Fail Us., Jake E. Timbes, Cameron Bateman, Justin Stace

Science University Research Symposium (SURS)

Lanthanide ions have attracted attention for applications in microwave electronics, memory devices, lighting applications, and chemical sensors. Terbium(III)-centered homoleptic complexes show promise as potential fluorescence-based chemical sensing agents. Tb(phen)2(NO3)3 (phen = 1,10-phenothroline) exhibits striking visible emission when excited by short-wave ultraviolet light; this emission is completely quenched by exposure to water or strong acid. However, the luminescence returns under relatively benign conditions. Unfortunately, our array of terbium(III) complexes are notoriously insoluble; rendering standard analytical techniques useless to assess purity, notably, 1H and 13C-NMR. Titration is a useful technique to give us, an assurance of purity—in conjunction with the ad-hoc purity …

Kinetic Analysis Of A Carbon-Rich Sico Model System, Takhya Holley

Chemistry & Biochemistry Theses - Archive

Kinetic Analysis of a Silicon Oxycarbide (polymethylhydrosiloxane/divinylbenzene) material was done for meaning of kinetic analysis methodology development. The material was synthesized using the standard procedure from, Blum 2005. A series of TGA’s was done using non-isothermal experiments. The analysis involved an initial isoconversional analysis using Friedman method, then decomposition of processes into individual processes using the Fraser-Suzuki function. The validation agreed within 1%, which is permissible by the ICTAC recommendations. The activation energies of the individual processes were determined using the Friedman method.The pre-dominant process #2 was found to have an activation energy of 220 +- 20 kj/mol and first-order …

Estimating Vapor Pressures Of Pheromone Compounds Using Gas Chromatographic Retention, Bipasha Sarker

Chemistry & Biochemistry Theses - Archive

Accurate determination of the vapor pressures of organic materials is important for predicting the sample’s environmental impact. It is difficult to directly measure accurate and precise vapor pressures of chemical compounds with direct experimental methods. Thus, indirect or predictive models for estimating vapor pressures are used. In this study, we follow a gas−liquid chromatography (GLC)-based approach, where retention data is correlated with vapor pressure using multiple reference standards. The method (GLC-RTyS) requires temperature-dependent retention factors (k-values) for test compounds and reference standards with known vapor pressures at matching temperatures. It has been observed that reference standards selected according to functional …

Epitaxial Growth Of Metal-Organic Framwork Thin Films By Electro-Conversion And Electrodeposition, Xiaoting Zhang

Doctoral Dissertations

Electrochemical epitaxy is a facile and inexpensive soft-solution process to fabricate highly ordered thin films. This research focuses on the epitaxial growth of metal-organic framework (MOF) thin films by electrochemical methods which include electro-conversion and electrodeposition.

First, an electrochemical conversion pathway was invented to achieve epitaxial MOF thin films. Epitaxial single-domain Cu-BTC(111) thin films were manufactured by electrochemical oxidation of Cu₂O(111) films electrodeposited on single-crystal Au(111). The single-crystal-like Cu-BTC(111) thin films with out-of-plane and in-plane order provide well-aligned 3.5 Å triangular windows along the [111] direction. Cu-BTC(111) foils were fabricated from the Cu-BTC/Cu₂O system by electrochemical …

Supporting Information For: "Synthesis And Characterization Of Γ-Acyloxyl-Ε-Caprolactones”, Greyson Greischar, Tapiwa Gono Phiri, Ellie Haljun, Jenna Ray, Meheret Ourgessa, Garrett Thesing, Lila Lofving, Aidan Clark, Suzanna Bator, Durwynn Jno Baptise, Wyatt Cole, Michael Itschner, Yutan D.Y.L. Getzler

Data Sets

This dataset contains the raw, unprocessed NMR data for the title compounds of the paper "Synthesis and characterization of γ-acyloxyl-ε-caprolactones” published in iScience (DOI: 10.1016/j.isci.2026.115190. NMR spectra were acquired on a JEOL-ECZS 400 MHz spectrometer in CDCl3 (Cambridge Isotope Labs, 99.8% D) and are saved in the .jdf format. Chemical structures in this document will be represented in the SMILES format. The paper details the synthesis of eight lactones, with variation of the exocyclic ester. Within this set, we consider CC(OC(CC1)CCOC1=O)=O (7-oxooxepan-4-yl acetate or γ-acetyl-ε-caprolactone) to be the parent compound. The R group pendant from the exocylic carbonyl in this …

Hydrogen Peroxide Production From Light-Driven Water Oxidation Via Nickel Oxide-Titanium Dioxide Heteronanocrystals, Mahfuz Ahammed Swadhen

Dissertations and Theses

High dependence on fossil fuels for energy carries risks for the environment, health, energy, and geopolitical stability. One of the solutions to address this is solar energy utilization, and the use of semiconductors for photocatalytic water splitting is a tantalizing prospect. An n-type semiconductor TiO2 combined with p-type NiO producing a heteronanojunction shows effective light-driven oxidation of H2O into H2O2. We developed a synthetic method to attach NiO nanoparticles on the surface of anatase TiO2 nanorods. We characterized the materials with UV-visible spectroscopy, powder X-ray diffraction, and electron microscopy. We immobilized the HNCs on fumed silica and removed organic surfactants …

Functionalized 2d Hexaazatriphenylene As Hydrogen Storage Platform: A Dft-Guided Design Approach, Islam Gomaa

Nanotechnology Research Centre

No abstract provided.

First-Principles Modeling Of Nitazoxanide Analogues As Prospective Pfor-Targeted Antibacterials, Islam Gomaa

Nanotechnology Research Centre

Pyruvate:ferredoxin oxidoreductase (PFOR) is a key Achilles’ heel in anaerobic pathogens. We integrate electronic-structure calculations (DFT), cheminformatic QSAR metrics, and residue-resolved docking to distill a concise “recognition code” and translate it into practical design rules. Using nitazoxanide (Nita; ΔG(bind) ≈ −10.0 kcal·mol−1) as a well-established reference, productive binding requires a conserved triad: a hydrogen-bond donor addressing Thr-997 and Cys-840, a π–π stack with Phe-869, and a recurrent π–σ contact to Thr-997 that orients the scaffold. Deacetylation to tizoxanide unmasks the phenolic donor and raises local electrophilicity, yet it also slightly loosens pocket packing (−9.6 kcal·mol−1). Strategic halogenation introduces a σ-hole …

Rhenium Chalcogenide Clusters Containing Para-Substituted Phenylacetylide Ligands: Synthesis, Characterization, And Investigation Of Substituent Effects On Spectroscopic And Electrochemical Properties, Katherine L. Helmink, Cory A. Hicks, B. Sage Lauper-Cook, Steven J. Peters, Christopher J. A. Daley, Yann Molard, Lisa F. Szczepura

Faculty Publications – Chemistry

Four new organometallic [Re₆Se₈]²⁺-based cluster complexes containing para-substituted phenylacetylide ligands, [Re₆Se₈(PEt₃)₅(C≡C–C₆H₄–X)](SbF₆) where X = NO₂, CO₂Me, CH₃, and OMe, have been synthesized and fully characterized using ¹H, ¹³C{¹H} and ³¹P{¹H} NMR, IR, and UV–vis spectroscopy, HRMS, and elemental analysis. Three of these cluster complexes, [Re₆Se₈(PEt₃)₅(C≡C–C₆H₄–NO₂)]⁺, [Re₆Se₈(PEt …

New Psychoactive Substances Detected In Wastewater Samples Collected Along The Interstate Highway Rest Areas In Kentucky, Durga Prasad Kodati

Murray State Theses and Dissertations

The rapid emergence and proliferation of new psychoactive substances (NPS) pose significant challenges to public health and law enforcement. The potential for abuse and toxicity of these substances, which are intended to mimic the effects of controlled drugs, has been raising concerns as these compounds are designed to evade being regulated. There are traditional methods of tracking NPS, such as seizures and forensic toxicology, but they are delayed and seldom effective because these substances continue to evolve rapidly. Wastewater-based epidemiology (WBE) has emerged as a promising tool for real-time surveillance of drug consumption. The primary objective of this research was …

Lead-Free Alternatives And Toxicity Mitigation Strategies For Sustainable Perovskite Solar Cells: A Critical Review, Md Helal Miah, Mayeen Uddin Khandaker, Md Jakir Hossen, None Noor-E-Ashrafi, Ismat Jahan, Md Shahinuzzaman, Mohammad Nur-E-Alam, Mohamed Y. Hanfi, Md Habib Ullah, Mohammad Aminul Islam

Research outputs 2022 to 2026

The growing global energy demand has prompted an increase in research into renewable energy conversion technologies. Although lead-based perovskite solar cells (PSCs) offer high efficiency as well as low manufacturing costs, the toxicity of the material is still a serious hurdle to their commercialization and widespread adoption. Amid ongoing efforts to develop lead-free perovskites, over the last few years, growing attention on mitigating the toxicity of lead by inhibiting the leakage of lead from PSCs has been observed. This review discusses the potential replacement of lead from PSCs and explores various approaches to mitigate lead leakage from PSCs. In addition, …

Characterization And Leaching Feasibility Studies Of Copper Flue Dust For The Recovery Of Main And Trace Metals, Fardis Nakhaei, Marek Locmelis, Lana Alagha, Michael S. Moats, Carlos Eyzaguirre, Cory Smith

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Although copper smelter dust (CSD) is classified as hazardous waste, it also serves as a valuable secondary resource, offering potential for the recovery of critical elements. In this study, CSD samples were collected from the waste heat boiler (WHB) and electrostatic precipitator (ESP) units connected to the flash smelting furnace at a copper smelter. The representative samples were extensively characterized by particle size, and chemical and mineralogical analyses. Following sample characterization, leaching experiments were performed to evaluate the potential extraction of Cu, Fe, As, Zn, Pb, In, Ga, and Ge from the flue dusts. Distilled water, H2SO4, and HCl were …

Characterizing The Transient Emission Of Particles And Gases From A Single Puff Of Electronic Cigarette Smoke, Kashala Fabrice Kapiamba, Steven Achterberg, Ta Chun Lin, Philip D. Whitefield, Yue-Wern Huang, Yang Wang

Chemistry Faculty Research & Creative Works

This study employed high-time-resolution systems to examine the transient properties of aerosols and gases emitted from electronic cigarette (EC) puffs. Using a fast aerosol sizer, we measured particle size distributions (PSDs) across various EC brands (JUUL, VUSE, VOOPOO), revealing sizes ranging from 5 to 1000 nm at concentrations of 107 to 1010 cm-3. Most aerosols were found to be in the ultrafine range (below 100 nm), with JUUL-, VUSE-, and VOOPOO-producing aerosols with geometric mean sizes of 19.9, 47.3, and 29.4 nm, respectively. Applying the International Commission on Radiological Protection (ICRP) deposition model and assuming no further evolution of aerosols …

Instantaneous Hydrolysis Of Methyl Paraoxon Nerve Agent Simulant Is Catalyzed By Nontoxic Aminoguanidine Imines, Emmanuel Kingsley Darkwah, Puspa Aryal, Chi Zhang, Charles B. Musgrave, William A. Goddard, V. Prakash Reddy

Chemistry Faculty Research & Creative Works

Exposure to organophosphate-based nerve agents and pesticides poses health and security threats to civilians, soldiers, and first responders. Thus, there is a need to develop effective decontamination agents that are nonhazardous to human health. To address this, we demonstrate that instantaneous hydrolysis of methyl paraoxon (Me-POX), a nerve agent simulant, can be achieved in the presence of aminoguanidine imines at pH 10: ● the pyridine-4-aldehyde aminoguanidine-imine (1) and ● the 2,3-butanedione aminoguanidine-imine (2). The hydrolysis of Me-POX under these conditions is substantially faster than that of the state-of-the-art decontaminating agent, Dekon-139 (2,3-butanedione oxime, potassium salt). Furthermore, Dekon-139 shows adverse effects …

Pla-Based Bone Tissue Engineering Scaffolds Incorporating Hydroxyapatite And Bioactive Glass Using Digital Light Processing, Engin Gepek, Fateme Fayyazbakhsh, Lev Suliandziga, Vadym Mochalin, Osman Iyibilgin, Yue-Wern Huang, Ming C. Leu

Chemistry Faculty Research & Creative Works

Bone tissue engineering (BTE) aims to repair bone defects using biocompatible materials with tailored geometries and pore structures, providing appropriate mechanical support and control over biodegradation kinetics to promote bone growth. In this study, we utilized digital light processing (DLP) 3D printing to fabricate scaffolds with varying pore sizes using polymer–ceramic slurries composed of polylactic acid (PLA) as the main polymer matrix, incorporated with hydroxyapatite (HA) and bioactive borate glass (BBG) at various ratios. We studied the effect of composition on rheological behavior, printability, mechanical properties, bioactivity, degradation rate, and biocompatibility. While HA increased viscosity and reduced printing accuracy, it …

Tricatalytic Organocatalyst-Enzyme Hybrid Cascade For Improving Complete Oxidation Of Glucose To Carbon Dioxide, Adam Milam, Rokas Gerulskis, Jose Intano, Shelley D. Minteer

Chemistry Faculty Research & Creative Works

Advancing energy harvesting is crucial for the development of wearable and implantable technologies. Given the high concentration of complex fuels, such as glucose, in biological fluids, biofuel cells present a promising avenue for exploration. However, glucose fuel cells that have been published to date typically catalyze only one or two of the maximum 12 oxidation steps for glucose, resulting in low energy density. Although known multienzyme cascades, which are sequential biochemical reactions where multiple enzymes work in tandem to convert a substrate into a final product, have addressed this inefficiency, they come with several trade-offs, such as reduced power density …

Enhanced Biofuel Cells Based On A Hybrid Enzymatic/Bimetallic Composite For Complete Lactate Catalytic Electrooxidation, Jefferson Honorio Franco, João Victor Bonaldo, Shelley D. Minteer, Adalgisa R. De Andrade

Chemistry Faculty Research & Creative Works

We describe complete lactate electrooxidation in an enzymatic biofuel cell that combines the catalytic action of the bimetallic composite Ru@Pt-CNT and the enzyme oxalate oxidase (OxOx). The Ru@Pt-CNT/OxOx hybrid electrode was 2.0-fold more catalytically active than the electrode containing the bimetallic composite only. During chronoamperometric experiments, the hybrid electrode achieved a 35% higher maximum current density (2.65 ± 0.15 mA cm^-2) than the Ru@Pt-CNT electrode. Electrochemical impedance spectroscopy showed that the hybrid electrode had lower charge transfer resistance than the Ru@Pt-CNT electrode, confirming that OxOx had a high affinity for lactate during the bioelectrocatalytic reaction on the electrode …

Mechanical And Thermal Characterization Of Additively Manufactured Carbon/Nylon 12 And Carbon/Peek Composites, Matik Heskin, Bradley Deuser, Thomas P. Schuman, K. Chandrashekhara, John Bayldon, Jeff Degrange, Steven Patterson, Neiko Levenhagen

Chemistry Faculty Research & Creative Works

This study explores additive manufacturing of carbon fiber-reinforced thermoplastic composites using the Composite-Based Additive Manufacturing (CBAM) process. Carbon/Nylon 12 and Carbon/PEEK composites were fabricated and evaluated through mechanical (compression, tensile, flexural, and impact) and thermal (DSC and TGA) tests. Carbon/PEEK exhibited superior mechanical performance, with 97.5% higher tensile strength, 79.8% higher elastic modulus, and 59.6% higher flexural strength compared to Carbon/Nylon 12. Thermal testing showed that Carbon/PEEK had higher thermal stability, beginning degradation at 350 °C versus 298 °C for Carbon/Nylon. These results indicate that CBAM-fabricated Carbon/PEEK composites are suitable for applications requiring high strength and temperature resistance.

A New Paradigm For The Supramolecular Structure Of Laterally Offset Diarenes: Polymorphs Ii Of Para-Substituted Acetophenone Azines, Yp.Ph.(Me)C.N.N.C(Me).Ph.Yp (Y = Cl, Br, Ch3), Harmeet Bhoday, Kaidi Yang, Steven P. Kelley, Rainer Glaser

Chemistry Faculty Research & Creative Works

The crystal structures of polymorphs II of acetophenone azines Y_pPhRCNNCRPhY_p with R = CH₃ and Y = Cl (1M), Br (2M), and CH₃ (8M) are discussed. The azine molecules in polymorphs II are Ci-symmetric with trans-azine moieties and conrotatory phenyl twists. Polymorphs 1M-I and 2M-I contain C2-symmetric enantiomers with pronounced azine twists and disrotatory phenyl twists and allow for strong lateral double T-contacts. The three polymorphs II exemplify the new Paradigm IV for the supramolecular architectures of "laterally offset diarenes" and result in "shiplap/flat" idioteloamphiphile monolayers. Intralayer lateral attraction is provided by edge-to-face arene-arene contacts …

Electrochemically Active Molybdenum Phosphate With Open-Framework Structure, Sutapa Bhattacharya, Milad Aghayi-Anaraki, Nikolay Gerasimchuk, Steven P. Kelley, Amitava Choudhury

Chemistry Faculty Research & Creative Works

Somewhat less investigated, lithium ion containing molybdenum phosphate compounds are synthesized via simple template free hydrothermal method. Single-crystal X-ray diffraction (SCXRD) study reveals that the compounds Li_0.89Mo₂O_1.89F_0.11(PO₄)2(H₂PO₄)·xH₂O (x ≈1) and Li₃Mo₂O₂(PO₄)₃·xH₂O (x ≈1) crystallize in monoclinic C2/m and C2/c space group, respectively. The structures are built of alternate corner-sharing of MoO₆ octahedra and PO₄ tetrahedra forming layers, which are pillared by phosphate groups creating a 3D framework with channels. These …

Atomistic Mechanisms Of Ti3alc2 Etching: Oxidation, Surface Stability, And Selectivity, Valentina Nesterova, Ana Maria Stratulat, Walter Malone, Vadym Mochalin, Majid Beidaghi, Konstantin Klyukin

Chemistry Faculty Research & Creative Works

Mechanisms governing MAX-phase etching set the properties and stability of resulting MXenes, yet the details of this complex process remain poorly understood. Combining thermodynamic analysis of surface chemistries with ab initio molecular dynamics and enhanced free-energy sampling, we directly model elementary steps at the MAX/etching solution interface. We find that purely thermodynamic analysis overestimates etching selectivity, which is governed by the kinetics of elementary reaction steps. Our calculations reveal that initial exposure to water drives localized, thermodynamically favored edge oxidation that seeds MXene-like terminations into the uppermost layers of Ti₃AlC₂ with oxygen occupying the interlayer space between …

Impact Of Y-Mixer Geometry And Flow Rate Modulation On Chemical Gradient Generators In Microfluidic Devices, Elizabeth Thurston Hutton

College of Graduate Studies: Theses & Dissertations

Various microfluidic structures are devised to generate tunable, stable spatiotemporal chemical gradients for single-cell studies. This work addresses the role of Y-mixer junctions in generating nonlinear gradients by increasing the width of one arm (bias), which is suspected to cause premature diffusion within the mixer. This study introduced a cinching feature to narrow the wider arm locally and redefine the junctions of these biased Y-mixers using four novel geometries defined by a 5-micrometer drawing rule. Furthermore, three flow rate factors allowed us to explore the impact on the generated gradient landscapes. The results showed that the four novel designs similarly …

Quantifying Inositol Phosphate Dephosphorylation To Understand The Role Of Recalcitrant Organic Phosphorus Forms On Harmful Algal Blooms In Freshwater Systems, Iffat Tasnim

College of Graduate Studies: Theses & Dissertations

Organophosphorus such as phytic acid, a surrogate species of inositol phosphate (IP), may serve as a source for orthophosphate (OP) in freshwater. In absence of OP, competent aquatic microorganisms upregulate the production of specialized enzymes to obtain growth-sustaining OP from organic phosphorus (org-P) forms. The contribution of recalcitrant org-P to the OP pool has been overlooked due to the lack of capable tools to measure OP production from org-P accurately. The objective of this study was to quantify OP production from phytic acid (a surrogate form of recalcitrant org-P) to assess the contribution of recalcitrant org-P forms to the total …

Verification Of Real-Time Smoke Simulations: A Case Study On Early Summer North American Wildfire Events, Daniel Bonilla

Pitzer Senior Theses

As wildfire intensity and frequency escalate in times of unprecedented climate change and severe droughts, it is important to enhance forecasting models that accurately and efficiently predict wildfire smoke movement. NOAA’s experimental Rapid-Refresh Forecasting System with Smoke and Dust (RRFS-SD) aims to improve upon the High-Resolution Rapid Refresh- Smoke (HRRR-Smoke), by extending the domain to include all of North America and incorporating new developments in physics and wildfire parameterizations. Our work explores the process of adding satellite Aerosol Optical Depth (AOD) data, through AERONET, as an additional method of verification of the RRFS-SD experimental model. Using a case study on …

Organic Geochemical Evidence For Life In Archean Rocks Identified By Pyrolysis-Gc-Ms And Supervised Machine Learning, Michael L. Wong, Anirudh Prabhu, Conel O'D. Alexander, H. James Cleaves Ii, George D. Cody, Grethe Hystad, Marko Bermanec, Wouter Bleeker, C. Kevin Boyce, Andrea Corpolongo, Andrew D. Czaja, Souvik Das, Robert R. Gaines, Daniel D. Gregory, John A. Jaszczak, Emmanuelle J. Javaux, Jaganmoy Jodder, Andrew H. Knoll, Martin Van Kranendonk, Katie M. Maloney, Nora Noffke, Robert Rainbird, Emersyn Slaughter, Eva E. Stüeken, Roger E. Summons, Frances Westall, Jasmina Wiemann, Shuhai Xiao, Robert M. Hazen

OES Faculty Publications

Throughout Earth’s history, organic molecules from both abiogenic and biogenic sources have been buried in sedimentary rocks. Most of these organic molecules have been significantly altered by geologic processes through deep time. Nonetheless, the nature and distribution of those ancient fragmentary organic remains have the potential to reveal diagnostic biomolecular information after billions of years of burial. Here, we analyzed 406 fossil, modern biological, meteoritic, and synthetic samples using pyrolysis gas chromatography and mass spectrometry. We explored these analytical data via supervised machine-learning methods to discriminate samples of biogenic vs. abiogenic origin, plant vs. animal phylogenetic affinity, and photosynthetic vs. …

Transient Transmembrane-Electrostatically Localized Protons And Transmembrane Potential In A Laser Flashed Bacteriorhodopsin Purple Membrane Open Flat Sheet - Summary, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

The transmembrane-electrostatically localized protons/cations charges (TELCs, also known as TELPs) model may serve as a unified framework to explain a wide range of bioenergetic phenomena. Transient transmembrane-electrostatically localized protons (TELPs) and transmembrane potential in a laser flash-energized bacteriorhodopsin (bR) purple membrane (PM) open flat sheet are now better analyzed. Under the Heberle et al. (1994) experimental conditions, the number of bR molecules is now calculated to be 8200 per PM open flat sheet with a diameter of 600 nm. With a single-turnover laser flash intensity of 3 mJ/cm² to photoexcite 10% of the bR molecules, the laser flash-induced peak TELCs …