Biochemistry Commons^™

Bodipy-Based Light-Responsive Materials, Zhaoxiong Wan

Dissertations

The energy required for life on our planet is provided by light. In science, light is an important and powerful tool for measuring and modifying substances. For example, under the effect of illumination, light-responsive materials can change their physical and chemical properties. Photochemistry is a branch of research to study the effects of light irradiation on chemical structures and reactions. Some photochemical changes could lead to chemical bond dissociation (such as in photosynthesis) and structure isomerization (such as in the retina). Photochemistry has a strong relationship with human lives and it is essential in many ways. Among photophysics, fluorescence emission …

Targeting Heat Shock 27 Kda Protein Induces Androgen Receptor Degradation, Yaxin Li

ETD Archive

Glioblastoma (GBM) is the most common and aggressive brain tumor, with very poor prognosis. Androgen receptor (AR) plays a significant role in the progression of GBM, and anti-androgen agents have the potential to be used for the treatment of GBM. However, AR mutation commonly happens in GBM, which makes the anti-androgen agents less effective. Heat shock 27 kDa protein (HSP27) is a well-documented chaperone protein to stabilize AR. Inhibition of HSP27 results in AR degradation regardless the mutation status of AR, which makes HSP27 a good target to abolish AR in GBM. Identified compound I ((N-(3-((2,5-dimethoxybenzyl)oxy)-4-(methylsulfonamido) phenyl)-4-methoxybenzamide) inhibits GBM cell …

Cysteine Metallochemistry And Metal Binding: Quantification Of The Thermodynamic Foundations Of Cellular Homeostasis, Matthew R. Mehlenbacher

Dartmouth College Ph.D Dissertations

Metals are required for life. Many metalloproteins contain cysteine in their metal-binding site (MBS) and cysteines are unique in that they are reactive, and strongly bind certain metals, which aid in metal selectivity and specificity. Using isothermal titration calorimetry (ITC), the thermodynamic foundation for metal binding, cellular protection, and transcriptional regulation, which all utilize cysteines in their MBS, are quantified.

In bacteria there are metalloprotein pathways that actively uptake mercury, which are regulated by the metalloregulatory protein MerR. MerR de-represses the transcription of these mer proteins in a metal-dependent manner. Using ITC, the thermodynamic foundation of the negative allosteric coupling …

A New Insight Into Fungal Cell Wall Architecture By Functional Genomics And Solid-State Nmr Along With Recent Advancements In Dynamic Nuclear Polarization For Analyzing Biomolecules, Arnab Chakraborty

LSU Master's Theses

This dissertation summarizes the findings related to the way by which supramolecular architecture of fungal cell wall changes with genetic mutation, dispensing genes responsible for biosynthesis of cell wall polysaccharides. This is necessary because without perfect picture of how supramolecular assembly changes with genetic mutation it is hard to assess new anti-fungal targets. Alongside this we have highlighted how recent advancement into Dynamic Nuclear Polarization (DNP) methods improved characterization of biomolecules both in case of labeled and unlabeled samples.

First study utilized Solid-state NMR (SSNMR) which is a non-destructive technique hence enabled us for the first time to deduce how …

Cell‑Controlled Dynamic Surfaces For Skeletal Stem Cell Growth And Differentiation, Hilary J. Anderson, Jugal Kishore Sahoo, Julia Wells, Sebastiaan Van Nuffel, Hala S. Dhowre, Richard O. C. Oreffo, Mischa Zelzer, Rein V. Ulijn, Matthew J. Dalby

Advanced Science Research Center

Skeletal stem cells (SSCs, or mesenchymal stromal cells typically referred to as mesenchymal stem cells from the bone marrow) are a dynamic progenitor population that can enter quiescence, self-renew or differentiate depending on regenerative demand and cues from their niche environment. However, ex vivo, in culture, they are grown typically on hard polystyrene surfaces, and this leads to rapid loss of the SSC phenotype. While materials are being developed that can control SSC growth and differentiation, very few examples of dynamic interfaces that reflect the plastic nature of the stem cells have, to date, been developed. Achieving such interfaces is …

Du Undergraduate Showcase: Research, Scholarship, And Creative Works: Abstracts, Emma Aggeler, Elena Arroway, Daisy T. Booker, Justin Bravo, Kyle Bucholtz, Megan Burnham, Nicole Choi, Spencer Cockerell, Rosie Contino, Jackson Garske, Kaitlyn Glover, Caroline Hamilton, Haley Hartmann, Madalyne Heiken, Colin Holter, Leah Huzjak, Alyssa Jeng, Cole Jernigan, Chad Kashiwa, Adelaide Kerenick, Emily King, Abigail Langeberg, Maddie Leake, Meredith Lemons, Alec Mackay, Greer Mckinley, Ori Miller, Guy Milliman, Katherine Miromonti, Audrey Mitchell, Lauren Moak, Megan Morrell, Gelella Nebiyu, Zdenek Otruba, Toni V. Panzera, Kassidy Patarino, Sneha Patil, Alexandra Penney, Kevin Persky, Caitlin Pham, Gabriela Recinos, Mary Ringgenberg, Chase Routt, Olivia Schneider, Roman Shrestha, Arlo Simmerman, Alec Smith, Tessa Smith, Nhi-Lac Thai, Kyle Thurmann, Casey Tindall, Amelia Trembath, Maria Trubetskaya, Zachary Vangelisti, Peter Vo, Abby Walker, David Winter, Grayden Wolfe, Leah York

DU Undergraduate Research Journal Archive

Abstracts from the DU Undergraduate Showcase.

Analysis Of The Light Responsive Azobenzene Peptide Nucleic Acid Duplexes, Kat Nguyen

Honors College Theses

Peptide nucleic acids (PNAs) are oligonucleotide analogues in which the sugar-phosphate backbone has been replaced by a pseudopeptide skeleton. Since PNAs use the natural nucleobases (Adenine, Thymine, Cytosine, Uracil, and Guanine) found in either DNA and/or RNA, they are able to hybridize according to Watson-Crick base-pairing to form duplexes. PNA is a promising therapeutic agent because they can function as antigene or antisense chemical agents. To further enhance their utility, we aim to incorporate a photoswitchable moiety using azobenzene. Here, we report the results of the synthesis and purification of a photoswitchable 11 mer PNA along with initial characterization efforts.

Unusual High-Frequency Mechanical Properties Of Polymer-Grafted Nanoparticle Melts, Mayank Jhalaria, Yu Chang, Yucheng Huang, Brian C. Benicewicz, Sanat K. Kumar, George Fytas

Faculty Publications

Brillouin light spectroscopy is used to measure the elastic moduli of spherical polymer-grafted nanoparticle (GNP) melts as a function of chain length at fixed grafting density (0.47  chains/nm²) and nanoparticle radius (8 nm). While the moduli follow a rule of mixtures (Wood’s law) for long chains, they display enhanced elasticity and anomalous dissipation for graft chains <1⁢0⁢0  kDa. GNP melts with long polymers at high 𝜎 have a dry zone near the GNP core, surrounded by a region where the grafts can interpenetrate with chain fragments from adjacent GNPs. We propose that the departures from Wood’s law for short chains are due to the effectively larger silica volume fraction in the region where sound propagates—this is caused by the short, interpenetrated chain fragments being pushed out of the way. We thus conclude that transport mechanisms (of gas, ions, sound, thermal phonons) in GNP melts are radically different if interpenetrated chain segments can be “pushed out of the way” or not. This provides a facile new means for manipulating the properties of these materials.

Covalent Modification Of Recombinant Protein With Reactive Thiols, Sawyer Dulaney, Bailey Taylor

Honors Theses

Many diseases cause chronic and painful inflammation in different body systems. One of the front-line drug classes to treat such inflammation is Nonsteroidal Anti-Inflammatory Drugs (NSAIDs). Despite the benefits of oral administration of NSAIDs, there are drawbacks to their long-term usage because they can cause detrimental effects on off-target systems in the body such as the liver, kidney, or the lining of the intestinal tract. An alternative to NSAIDs is the usage of hydrogels for targeted drug delivery. Hydrogels can provide drug delivery in a specific portion of the site of inflammation, thus allowing higher doses of medication to be …

Investigation Of The Binding Domain Interfaces Of The C-Terminus Of The Albino3 Insertase And The 43kda Chloroplast Signal Recognition Particle Subunit Via Single Molecule Förster Resonance Energy Transfer, Amanda Tomanek

Chemistry & Biochemistry Undergraduate Honors Theses

Fluorescent labeling is a technique used for visualizing functional groups contained in biomolecules by fluorescence imaging. This technique was used in this project to analyze post-translational targeting of light-harvesting chlorophyll-binding proteins (LHCP), which are the core complexes that harvest sunlight to drive photosynthetic electron transfer. This protein is synthesized in the cytosol and post-translationally targeted to the stroma of chloroplasts. CpSRP43 is a signal recognition particle (SRP) subunit unique to chloroplasts, which has been shown to interact with the stroma-soluble C-terminus of the thylakoid-bound Albino3 insertase (Alb3-Cterm). In the chloroplast stroma, targeting to thylakoids is performed via the cpSRP pathway …

Role Of E168d In M. Tuberculosis Igps Catalysis, Hedda Booter

Theses, Dissertations and Culminating Projects

Mycobacterium tuberculosis is a bacterium that affects the lungs and causes tuberculosis, infecting over 10 million people worldwide each year. Owing to the organism’s evolving drug resistance, existing antibiotics no longer combat the disease. The need to discover new drug targets has never been greater. Previous findings suggest that the protein IGPS (indole-3-glycerol phosphate synthase) in M. tuberculosis (MtIGPS) may be a target in the treatment of the disease. MtIGPS catalyzes the fourth step in the tryptophan biosynthetic process. The ability to create their own tryptophan is a major advantage that many bacteria have. The role of E168, in the …

Design, Synthesis, And Analysis Of Paired Coiled-Coil Peptidic Molecular Building Blocks Used For Linearly Controlled Self-Assembly Of Α-Helical Coiled-Coil Heterodimer Peptide Pairs, Jason Distefano

Chemistry Theses

Molecular building blocks are fundamental to biological synthesis and processes and have been utilized in advanced materials, drugs and drug delivery systems, and biotechnology. Proteins have been used as molecular building blocks for the construction of complex, well-ordered structures. Coiled-coil protein domains are essential subunits used for the oligomerization of protein complexes, gene expression, and structural elements of biological materials. The synthesis and assembly of proteins utilizing coiled-coil motifs are of great scientific interest due to their potential applications in disease treatment, biomechanical motors, nanoscale delivery systems, etc. However, assembling protein complexes with specific morphology is still challenging because …

Foldamers Reveal And Validate Therapeutic Targets Associated With Toxic Α-Synuclein Self-Assembly, Jemil Ahmed, Tessa C. Fitch, Courtney M. Donnelly, Johnson A. Joseph, Tyler D. Ball, Mikaela M. Bassil, Ahyun Son, Chen Zhang, Aurélie Ledreux, Scott Horowitz, Yan Qin, Daniel Paredes, Sunil Kumar

Chemistry and Biochemistry: Faculty Scholarship

Parkinson’s disease (PD) is a progressive neurodegenerative disorder for which there is no successful prevention or intervention. The pathological hallmark for PD involves the self-assembly of functional Alpha-Synuclein (αS) into non-functional amyloid structures. One of the potential therapeutic interventions against PD is the effective inhibition of αS aggregation. However, the bottleneck towards achieving this goal is the identification of αS domains/sequences that are essential for aggregation. Using a protein mimetic approach, we have identified αS sequences-based targets that are essential for aggregation and will have significant therapeutic implications. An extensive array of in vitro, ex vivo, and in vivo assays …

Evaluating Alternative Ebullition Models For Predicting Peatland Methane Emission And Its Pathways Via Data–Model Fusion, Shuang Ma, Lifen Jiang, Rachel M. Wilson, Jeff P. Chanton, Scott Bridgham, Shuli Niu, Colleen M. Iversen, Avni Malhotra, Jiang Jiang, Xingjie Lu, Yuanyuan Huang, Jason Keller, Xiaofeng Xu, Daniel M. Ricciuto, Paul J. Hanson, Yiqi Luo

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Understanding the dynamics of peatland methane (CH4) emissions and quantifying sources of uncertainty in estimating peatland CH4 emissions are critical for mitigating climate change. The relative contributions of CH4 emission pathways through ebullition, plant-mediated transport, and diffusion, together with their different transport rates and vulnerability to oxidation, determine the quantity of CH4 to be oxidized before leaving the soil. Notwithstanding their importance, the relative contributions of the emission pathways are highly uncertain. In particular, the ebullition process is more uncertain and can lead to large uncertainties in modeled CH4 emissions. To improve model simulations of CH4 emission and its pathways, …

Targeting Platelets Using Ionic Liquid Coated Nanoparticles, Karen Mun Wong

Honors Theses

Platelets are key players in our body’s inflammatory processes upon activation, which can create physiological problems. Researchers are actively seeking solutions by targeting platelets with therapeutics. The objective of the research in this thesis was to investigate a new and potentially less invasive drug delivery platform using nanoparticles. The topic of the project was to explore the world of ionic liquids and their abilities, when coated on nanoparticles, to bind to platelets. A library of choline carboxylic acid-based ionic liquids (ILs) was first synthesized via salt metathesis while PLGA-based nanoparticles were simultaneously being synthesized via the nanoprecipitation method. The ionic …

Bomb Calorimetry: A New Method Of Cec Determination, Trace Washburn

Undergraduate Research Conference

A new method of determining the cation exchange capacity (CEC) of clay minerals was examined. This method involved exchanging the smectite clay with organic cations and using bomb calorimetry to measure the energy of combustion of the material. Because the clay is noncombustible, the energy is completely dependent on the amount of organic present, which is dependent on the CEC of the clay. Two organic cations, tetrapentylammonium and octadecyltrimethylammonium , with similar size but much different shape were used. For clays with lower CECs, using the more symmetric ion yielded better accuracy (4.24%), while for clays with higher CEC, using …

Observing Reactive Events At The Aqueous Graphene Oxide Interface Using Deep Neural Network Potentials, Lukas Kim

Honors Capstones

No abstract provided.

In Situ Recording Of Mars Soundscape, S. Maurice, B. Chide, N. Murdoch, R. D. Lorenz, D. Mimoun, R. C. Wiens, A. Stott, X. Jacob, T. Bertrand, F. Montmessin, N. L. Lanza, C. Alvarez-Llamas, Stanley M. Angel, M. Aung, J. Balaram, O. Beyssac, A. Cousin, G. Delory, O. Forni, T. Fouchet, Et. Al.

Faculty Publications

Before the Perseverance rover landing, the acoustic environment of Mars was unknown. Models predicted that: (1) atmospheric turbulence changes at centimetre scales or smaller at the point where molecular viscosity converts kinetic energy into heat1, (2) the speed of sound varies at the surface with frequency^2,3 and (3) high-frequency waves are strongly attenuated with distance in CO₂ (refs.^2,3,4). However, theoretical models were uncertain because of a lack of experimental data at low pressure and the difficulty to characterize turbulence or attenuation in a closed environment. Here, using Perseverance …

1st Place Contest Entry: Designing Hollow Nanogels For Drug Delivery Applications, Mo Hijazi

Kevin and Tam Ross Undergraduate Research Prize

This is Mo Hijazi's submission for the 2022 Kevin and Tam Ross Undergraduate Research Prize, which won first place. It contains their essay on using library resources, their bibliography, and a summary of their research project on hollow-core nanogels.

Mo is a second-year student at Chapman University, majoring in Biological Sciences. Their faculty mentor is Dr. Molla Islam.

Prefusion Spike Protein Conformational Changes Are Slower In Sars-Cov-2 Than In Sars-Cov-1, Vivek Govind Kumar, Dylan S. Ogden, Ugochi H. Isu, Adithya Polasa, James Losey, Mahmoud Moradi

Chemistry & Biochemistry Faculty Publications and Presentations

Within the last 2 decades, severe acute respiratory syndrome coronaviruses 1 and 2 (SARS-CoV-1 and SARS-CoV-2) have caused two major outbreaks; yet, for reasons not fully understood, the coronavirus disease 2019 pandemic caused by SARS-CoV-2 has been significantly more widespread than the 2003 SARS epidemic caused by SARS-CoV-1, despite striking similarities between these two viruses. The SARS-CoV-1 and SARSCoV-2 spike proteins, both of which bind to host cell angiotensin-converting enzyme 2, have been implied to be a potential source of their differential transmissibility. However, the mechanistic details of prefusion spike protein binding to angiotensin-converting enzyme 2 remain elusive at the …

The Development Of Inhibitors For Sars-Cov-2 Orf8, My Thanh Thao Nguyen

CSB and SJU Distinguished Thesis

An unexpected outbreak of SARS-CoV-2 caused a worldwide pandemic in 2020. Many repurposed drugs were tested, but there are currently only three FDA approved antivirals (Merck’s antiviral Molnupiravir, Pfizer’s antiviral Paxlovid, and Remdisivir).1 Most of the antiviral drugs tested SARS-CoV-2 main protease and RNA-dependent RNA polymerase. However, it is important to explore different drug targets of SARS-CoV-2 to prepare for the virus mutations of the future. This research looks at an alternative approach in which SARSCoV- 2 Open Reading Frame 8 (ORF8), which has been shown to be a rapidly evolving hypervariable gene, was chosen to be the protein of …

Sars-Cov-2 Main Protease Inhibitors Repurposed For Hiv-1 Protease Binding, Jacob Minkkinen

CSB and SJU Distinguished Thesis

Severe acute respiratory syndrome (SARS-CoV-2) led to the COVID-19 global pandemic, with over 460 million cases of infection and over 6 million deaths since the start of the pandemic. SARS-CoV-2 is a retrovirus that utilizes a main protease (Mpro). Mpro is a catalytic cys/his protease. Several treatments were proposed to stop the pandemic including repurposing drugs to inhibit the Mpro. Another retrovirus that uses a protease is human immunodeficiency virus (HIV-1) which has been a global epidemic for 40 years and is a devastating disease that attacks the immune system. HIV-1 has infected 79.5 million people and has killed an …

Datadescription-Detection Of Sulfur Dioxide By Broadband Cavity-Enhanced Absorption Spectroscopy (Bbceas), Ryan Thalman, Nitish Bhardwaj, Callum Flowerday, Jaron C. Hansen

ScholarsArchive Data

Files archived include the following:

Figure1.txt This file contains all the data used to make Figure 1 in the paper.

Figure4.txt This file contains all the data used to make Figure 4 in the paper.

Figure5.txt This file contains all the data used to make Figure 5 in the paper.

Figure6.txt This file contains all the data used to make Figure 6 in the paper.

Figure7.txt This file contains the code, written in Igor, that was used to generate this figure.

Figure8.txt This file contains all the data used to make Figure 8 in the paper.

Figure9.txt This file contains …

Attempted Synthesis & Antibacterial Properties Of Apt-6k Against Ndm-1 K. Pneumoniae, Alec Bofetiado

Honors Theses

NDM-1 K. pneumoniae is a highly resistant bacterial organism that is capable of causing debilitating nosocomial infections in immunocompromised patients. Only "last-resort" antibiotics--such as colistin--work against this organism. Therefore, new antibiotics are needed to help fight against these types of infections. APT-6K is a novel compound that was demonstrated to be effective against MRSA with nanomolar concentrations in a prior study. Novel methods of APT-6K synthesis and its testing for antibiotic effects against NDM-1 K. pneumoniae were attempted in this research. APT-6K synthesis was unsuccessful. Commercially-prepared APT-6K also did not demonstrate growth inhibition against NDM-1 K. pneumoniae nor against a …

Repurposing Lansoprazole And Posaconazole To Treat Leishmaniasis: Integration Of In Vitro Testing, Pharmacological Corroboration, And Mechanisms Of Action, Yash Gupta, Steven Goicoechea, Jesus G. Romero, Raman Mathur, Thomas R. Caulfield, Daniel P. Becker, Ravi Durvasula, Prakasha Kempaiah

Chemistry: Faculty Publications and Other Works

Leishmaniasis remains a serious public health problem in many tropical regions of the world. Among neglected tropical diseases, the mortality rate of leishmaniasis is second only to malaria. All currently approved therapeutics have toxic side effects and face rapidly increasing resistance. To identify existing drugs with antileishmanial activity and predict the mechanism of action, we designed a drug-discovery pipeline utilizing both in-silico and in-vitro methods. First, we screened compounds from the Selleckchem Bio-Active Compound Library containing ~1622 FDA-approved drugs and narrowed these down to 96 candidates based on data mining for possible anti-parasitic properties. Next, we completed preliminary in-vitro testing …

One Planet: One Health. A Call To Support The Initiative On A Global Science-Policy Body On Chemicals And Waste, Werner Brack, Damia Barcelo Culleres, Alistair B.A. Boxall, Helene Budzinski, Sara Castiglioni, Adrian Covaci, Valeria Dulio, Beate I. Escher, Peter Fantke, Faith Kandie, Despo Fatta-Kassinos, Felix J. Hernandez, Klara Hilscherova, Juliane Hollender, Henner Hollert, Annika Jahnke, Barbara Kasprzyk-Hordern, Stuart J. Khan, Andreas Kortenkamp, Klaus Kuemmerer, Brice Lalonde, Marja H. Lamoree, Yves Levi, Pablo Antonio Lara Martin, Cassiana C. Montagner, Christian Mougin, Titus Msagati, Joerg Oehlmann, Leo Posthuma, Malcolm Reid, Martin Reinhard, Susan D. Richardson, Et. Al.

Faculty Publications

The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science–policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science–policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond …

Structural And Computational Studies Of The Sars-Cov-2 Spike Protein Binding Mechanisms With Nanobodies: From Structure And Dynamics To Avidity-Driven Nanobody Engineering, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Nanobodies provide important advantages over traditional antibodies, including their smaller size and robust biochemical properties such as high thermal stability, high solubility, and the ability to be bioengineered into novel multivalent, multi-specific, and high-affinity molecules, making them a class of emerging powerful therapies against SARS-CoV-2. Recent research efforts on the design, protein engineering, and structure-functional characterization of nanobodies and their binding with SARS-CoV-2 S proteins reflected a growing realization that nanobody combinations can exploit distinct binding epitopes and leverage the intrinsic plasticity of the conformational landscape for the SARS-CoV-2 S protein to produce efficient neutralizing and mutation resistant characteristics. Structural …

Natural Phaeosphaeride A Derivatives Overcome Drug Resistance Of Tumor Cells And Modulate Signaling Pathways, Victoria Abzianidze, Natalia Moiseeva, Diana Suponina, Sofya Zakharenkova, Nadezhda Rogovskaya, Lidia Laletina, Alvin A. Holder, Denis Krivorotov, Alexander Bogachenkov, Alexander Garabadzhiu, Anton Ukolov, Vyacheslav Kosorukov

Chemistry & Biochemistry Faculty Publications

n the present study, natural phaeosphaeride A (PPA) derivatives are synthesized. Anti-tumor studies are carried out on the PC3, K562, HCT-116, THP-1, MCF-7, A549, NCI-H929, Jurkat, and RPMI8226 tumor cell lines, and on the human embryonic kidney (HEK293) cell line. All the compounds synthesized turned out to have better efficacy than PPA towards the tumor cell lines listed. Among them, three compounds exhibited an ability to overcome the drug resistance of tumor cells associated with the overexpression of the P-glycoprotein by modulating the work of this transporter. Luminex xMAP technology was used to assess the effect of five synthesized compounds …

Studying Acetylation Of Aconitase Isozymes By Genetic Code Expansion, Jessica Araujo, Sara Ottinger, Sumana Venkat, Qinglei Gan, Chenguang Fan

Chemistry & Biochemistry Faculty Publications and Presentations

Aconitase catalyzes the second reaction of the tricarboxylic acid cycle, the reversible conversion of citrate and isocitrate. Escherichia coli has two isoforms of aconitase, AcnA and AcnB. Acetylomic studies have identified acetylation at multiple lysine sites of both E. coli aconitase isozymes, but the impacts of acetylation on aconitases are unknown. In this study, we applied the genetic code expansion approach to produce 14 site-specifically acetylated aconitase variants. Enzyme assays and kinetic analyses showed that acetylation of AcnA K684 decreased the enzyme activity, while acetylation of AcnB K567 increased the enzyme activity. Further in vitro acetylation and deacetylation assays were …

Amorphization Of Pseudocapacitive T−Nb2O5 Accelerates Lithium Diffusivity As Revealed Using Tunable Isomorphic Architectures, Wessel Van Den Bergh, Sean Wechsler, Hasala Nadeesini Lokupitiya, Lauren Jarocha, Kwangnam Kim, James Chapman, Kyoung E. Kweon, Brandon C. Wood, Steve Heald, Morgan Stefik Phd

Faculty Publications

Intercalationpseudocapacitancecan combinecapacitor-likepower densitieswith battery-likeenergy densities.Such surface-limitedbehaviorrequiresrapid diffusionwhere amorphizationcan increasesolid-statediffusivity.Here intercalationpseudoca-pacitivematerialswith tailoredextentsof amorphizationin T-Nb2O5are first reported.Amorphizationwas characterizedwithWAXS, XPS, XAFS, and EPR which suggesteda peroxide-rich(O22) surface that was consistentwith DFT predictions.A seriesof tunableisomorphicarchitecturesenabledcomparisonswhileindependentlyvaryingtransportparameters.Throughprocessof elimination,solid-statelithium diffusionwas identifiedas thedominantdiffusive-constraintdictatingthe maximumvoltagesweep rate for surface-limitedkinetics(vSLT), termed the Surface-LimitedThreshold(SLT). ThevSLTincreasedwith amorphizationhoweverstable cycling requiredcrystallineT-Nb2O5. A current-responsemodel using series-impedanceswell-matchedtheseobservations.This perspectiverevealedthat amorphizationof T-Nb2O5enhancedsolid-statediffusionby 12.2% and increasedsurface-limitationsby 17.0% (stablesamples).This approachenabledretaining95% lithiationcapacityat ~800mVs1(1,600C-rate equivalent).