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Articles 31 - 60 of 11768

Full-Text Articles in Physical Sciences and Mathematics

Β-Sheets Mediate The Conformational Change And Allosteric Signal Transmission Between The Aslov2 Termini, Sian Xiao, Mayar Terek Ibrahim, Gennady M. Verkhivker, Brian D. Zoltowski, Peng Tao Mar 2024

Β-Sheets Mediate The Conformational Change And Allosteric Signal Transmission Between The Aslov2 Termini, Sian Xiao, Mayar Terek Ibrahim, Gennady M. Verkhivker, Brian D. Zoltowski, Peng Tao

Mathematics, Physics, and Computer Science Faculty Articles and Research

Avena sativa phototropin 1 light-oxygen-voltage 2 domain (AsLOV2) is a model protein of Per-Arnt-Sim (PAS) superfamily, characterized by conformational changes in response to external environmental stimuli. This conformational change begins with the unfolding of the N-terminal A'α helix in the dark state followed by the unfolding of the C-terminal Jα helix. The light state is characterized by the unfolded termini and the subsequent modifications in hydrogen bond patterns. In this photoreceptor, β-sheets are identified as crucial components for mediating allosteric signal transmission between the two termini. Through combined experimental and computational investigations, the Hβ …


Novel Inhibitors To Mmpl3 Transporter Of Mycobacterium Tuberculosis By Structure-Based High-Throughput Virtual Screening And Molecular Dynamics Simulations, Hetanshi Choksi, Justin Carbone, Nicholas J. Paradis, Lucas Bennett, Candice Bui-Linh, Chun Wu Mar 2024

Novel Inhibitors To Mmpl3 Transporter Of Mycobacterium Tuberculosis By Structure-Based High-Throughput Virtual Screening And Molecular Dynamics Simulations, Hetanshi Choksi, Justin Carbone, Nicholas J. Paradis, Lucas Bennett, Candice Bui-Linh, Chun Wu

Faculty Scholarship for the College of Science & Mathematics

Tuberculosis (TB)-causing bacterium Mycobacterium tuberculosis (Mtb) utilizes mycolic acids for building the mycobacterial cell wall, which is critical in providing defense against external factors and resisting antibiotic action. MmpL3 is a secondary resistance nodulation division transporter that facilitates the coupled transport of mycolic acid precursor into the periplasm using the proton motive force, thus making it an attractive drug target for TB infection. In 2019, X-ray crystal structures of MmpL3 from M. smegmatis were solved with a promising inhibitor SQ109, which showed promise against drug-resistant TB in Phase II clinical trials. Still, there is a pressing need to discover more …


Highly Efficient Dopamine Sensing With A Carbon Nanotube-Encapsulated Metal Chalcogenide Nanostructure, Harish Singh, Jiandong Wu, Kurt A.L. Lagemann, Manashi Nath Mar 2024

Highly Efficient Dopamine Sensing With A Carbon Nanotube-Encapsulated Metal Chalcogenide Nanostructure, Harish Singh, Jiandong Wu, Kurt A.L. Lagemann, Manashi Nath

Chemical and Biochemical Engineering Faculty Research & Creative Works

Carbon nanotube-encapsulated nickel selenide composite nanostructures were used as nonenzymatic electrochemical sensors for dopamine detection. These composite nanostructures were synthesized through a simple, one-step, and environmentally friendly chemical vapor deposition method, wherein the CNTs were formed in situ from pyrolysis of a carbon-rich metallo-organic precursor. The composition and morphology of these hybrid NiSe2-filled carbon nanostructures were confirmed by powder X-ray diffraction, Raman, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy images. Electrochemical tests demonstrated that the as-synthesized hybrid nanostructures exhibited outstanding electrocatalytic performance toward dopamine oxidation, with a high sensitivity of 19.62 μA μM-1 cm-2, low detection limit, broad linear …


Induction Of Neuroinflammation And Brain Oxidative Stress By Brain-Derived Extracellular Vesicles From Hypertensive Rats, Xinqian Chen, Xin Yan, Leah Gingerich, Qing Hui Chen, Lanrong Bi, Zhiying Shan Mar 2024

Induction Of Neuroinflammation And Brain Oxidative Stress By Brain-Derived Extracellular Vesicles From Hypertensive Rats, Xinqian Chen, Xin Yan, Leah Gingerich, Qing Hui Chen, Lanrong Bi, Zhiying Shan

Michigan Tech Publications, Part 2

Neuroinflammation and brain oxidative stress are recognized as significant contributors to hypertension including salt sensitive hypertension. Extracellular vesicles (EVs) play an essential role in intercellular communication in various situations, including physiological and pathological ones. Based on this evidence, we hypothesized that EVs derived from the brains of hypertensive rats with salt sensitivity could trigger neuroinflammation and oxidative stress during hypertension development. To test this hypothesis, we compared the impact of EVs isolated from the brains of hypertensive Dahl Salt-Sensitive rats (DSS) and normotensive Sprague Dawley (SD) rats on inflammatory factors and mitochondrial reactive oxygen species (mtROS) production in primary neuronal …


Analyzing Biomedical Datasets With Symbolic Tree Adaptive Resonance Theory, Sasha Petrenko, Daniel B. Hier, Mary A. Bone, Tayo Obafemi-Ajayi, Erik J. Timpson, William E. Marsh, Michael Speight, Donald C. Wunsch Mar 2024

Analyzing Biomedical Datasets With Symbolic Tree Adaptive Resonance Theory, Sasha Petrenko, Daniel B. Hier, Mary A. Bone, Tayo Obafemi-Ajayi, Erik J. Timpson, William E. Marsh, Michael Speight, Donald C. Wunsch

Chemistry Faculty Research & Creative Works

Biomedical Datasets Distill Many Mechanisms Of Human Diseases, Linking Diseases To Genes And Phenotypes (Signs And Symptoms Of Disease), Genetic Mutations To Altered Protein Structures, And Altered Proteins To Changes In Molecular Functions And Biological Processes. It Is Desirable To Gain New Insights From These Data, Especially With Regard To The Uncovering Of Hierarchical Structures Relating Disease Variants. However, Analysis To This End Has Proven Difficult Due To The Complexity Of The Connections Between Multi-Categorical Symbolic Data. This Article Proposes Symbolic Tree Adaptive Resonance Theory (START), With Additional Supervised, Dual-Vigilance (DV-START), And Distributed Dual-Vigilance (DDV-START) Formulations, For The Clustering Of …


3d Pictorial Representations Of O2- And Ho2 Compared To Dft Results, Tzu-Hsiang Huang, Joseph D. Alia Mar 2024

3d Pictorial Representations Of O2- And Ho2 Compared To Dft Results, Tzu-Hsiang Huang, Joseph D. Alia

Chemistry Publications

The Linnett Double Quartet (LDQ) (1) and Bohr Orbit Bonding (BOB) (2) methods were used to accurately represent the spin density distribution for superoxide (O2 -) and hydroperoxyl radical (HO2). These structural pictures were superimposed on the spin density plot produced by DFT. The Valency Interaction Formula (VIF) method (3) was also applied to these molecules and it matched the NBOs from NBO analysis of DFT results. The interaction between O2 - and H2O were analyzed and the stronger basicity of the beta-spin electrons of superoxide was identified by looking at the LDQ structure and confirmed with NBO analysis. The …


Dna-Based Assay For Calorimetric Determination Of Protein Concentrations In Pure Or Mixed Solutions, Matthew W. Eskew, Patrick Reardon, Albert S. Benight Mar 2024

Dna-Based Assay For Calorimetric Determination Of Protein Concentrations In Pure Or Mixed Solutions, Matthew W. Eskew, Patrick Reardon, Albert S. Benight

Chemistry Faculty Publications and Presentations

It was recently reported that values of the transition heat capacities, as measured by differential scanning calorimetry, for two globular proteins and a short DNA hairpin in NaCl buffer are essentially equivalent, at equal concentrations (mg/mL). To validate the broad applicability of this phenomenon, additional evidence for this equivalence is presented that reveals it does not depend on DNA sequence, buffer salt, or transition temperature (Tm). Based on the equivalence of transition heat capacities, a calorimetric method was devised to determine protein concentrations in pure and complex solutions. The scheme uses direct comparisons between the thermodynamic stability of a short …


Two-Electron Density Of Three Electrons In A 1d Box: A Model System For Visualizing Spin Correlation Due To Antisymmetry Of Electrons, Joseph D. Alia Mar 2024

Two-Electron Density Of Three Electrons In A 1d Box: A Model System For Visualizing Spin Correlation Due To Antisymmetry Of Electrons, Joseph D. Alia

Chemistry Publications

Visual models for understanding electron density distribution in molecules are useful for chemical reasoning. The Lewis structure for example compares well to one-electron density when all electrons are paired. Linnett Double Quartet structures compare well to some kinds of free radical species. These approaches do not show the behavior of the total electron wavefunction when two electrons near each other. This behavior is a two- electron property and can be visualized with the model of three electrons in a one- dimensional box. The two-electron density of the three electron wavefunction described as a slater determinent of 1D particle-in-a-box spin- orbitals …


Limonene Enantiomeric Ratios From Anthropogenic And Biogenic Emission Sources, Shan Gu, Wentai Luo, Avisa Charmchi, Kevin J. Mcwhirter, Todd Rosenstiel, James F. Pankow Mar 2024

Limonene Enantiomeric Ratios From Anthropogenic And Biogenic Emission Sources, Shan Gu, Wentai Luo, Avisa Charmchi, Kevin J. Mcwhirter, Todd Rosenstiel, James F. Pankow

Chemistry Faculty Publications and Presentations

Emissions from volatile chemical products (VCPs) have been identified as contributors to air quality degradation in urban areas. Limonene can be a tracer compound for VCPs containing fragrances in densely populated regions, but limonene is also emitted from conifers that are planted in urban areas. This creates challenges for using limonene to estimate VCP emissions. In this study, the −/+ enantiomeric ratios of limonene from VCP and conifer emission sources were quantified to evaluate if this measurement could be used to aid in source apportionment and emission inventory development. Samples were analyzed using a gas chromatograph equipped with a chiral …


The Α-Crystallin Chaperones Undergo A Quasi-Ordered Co-Aggregation Process In Response To Saturating Client Interaction, Kirsten Lampi, Adam P. Miller, Susan E. O'Neill, Steve L. Reichow Mar 2024

The Α-Crystallin Chaperones Undergo A Quasi-Ordered Co-Aggregation Process In Response To Saturating Client Interaction, Kirsten Lampi, Adam P. Miller, Susan E. O'Neill, Steve L. Reichow

Chemistry Faculty Publications and Presentations

Small heat shock proteins (sHSPs) are ATP-independent chaperones vital to cellular proteostasis, preventing protein aggregation events linked to various human diseases including cataract. The α-crystallins, αA-crystallin (αAc) and αB-crystallin (αBc), represent archetypal sHSPs that exhibit complex polydispersed oligomeric assemblies and rapid subunit exchange dynamics. Yet, our understanding of how this plasticity contributes to chaperone function remains poorly understood. This study investigates structural changes in αAc and αBc during client sequestration under varying degree of chaperone saturation. Using biochemical and biophysical analyses combined with single-particle electron microscopy (EM), we examined αAc and αBc in their apo-states and at various stages of …


Using Flipped Classroom Modules To Facilitate Higher Order Learning In Undergraduate Organic Chemistry, Lauren R. Holloway, Tabitha Miller, Bryce Da Camara, Paul M. Bogie, Briana L. Hickey, Jack Barbera, Angie L. Lopez, Multiple Additional Authors Mar 2024

Using Flipped Classroom Modules To Facilitate Higher Order Learning In Undergraduate Organic Chemistry, Lauren R. Holloway, Tabitha Miller, Bryce Da Camara, Paul M. Bogie, Briana L. Hickey, Jack Barbera, Angie L. Lopez, Multiple Additional Authors

Chemistry Faculty Publications and Presentations

In an ongoing effort to incorporate active learning and promote higher order learning outcomes in undergraduate organic chemistry, a hybrid (“flipped”) classroom structure has been used to facilitate a series of collaborative activities in the first two courses of the lower division organic chemistry sequence. An observational study of seven classes over a five-year period reveals there is a strong correlation between performance on the in-class activities and performance on the final exam across all classes; however, a significant number of students in these courses continue to struggle on both the in-class activities and final exam. The Activity Engagement Survey …


Raw Nmr Data For Tripeptides, David J. Michaelis, Scott R. Burt, Mariur Rodriguez Moreno, Nye C. Johnson, Christopher B. Stewart, Mary L. Setelin, Adam X. Wayment, Braxton M. Felix Feb 2024

Raw Nmr Data For Tripeptides, David J. Michaelis, Scott R. Burt, Mariur Rodriguez Moreno, Nye C. Johnson, Christopher B. Stewart, Mary L. Setelin, Adam X. Wayment, Braxton M. Felix

ScholarsArchive Data

This data set contains primary data for 50 tripeptides that were generated as part of an advanced undergraduate laboratory experience in solid phase peptide synthesis. The raw data can be processed sing NMR interpretation software and can be used as problems for exams and quizzes or as supplementary materials for a laboratory experience


Toward A Coordinated Understanding Of Hydro-Biogeochemical Root Functions In Tropical Forests For Application In Vegetation Models, Daniela F. Cusack, Bradley Christoffersen, Chris M. Smith-Martin, Kelly M. Andersen, Amanda L. Cordeiro, Katrin Fleischer, S. Joseph Wright, Nathaly R. Guerrero-Ramírez, Laynara F. Lugli, Lindsay A. Mcculloch, Mareli Sanchez-Julia, Sarah A. Batterman, Caroline Dallstream, Claire Fortunel, Laura Toro, Lucia Fuchslueger, Michelle Y. Wong, Daniela Yaffar, Joshua B. Fisher, Marie Arnaud, Lee H. Dietterich, Shalom D. Addo-Danso, Oscar J. Valverde-Barrantes, Monique Weemstra, Jing Cheng Ng, Richard J. Norby Feb 2024

Toward A Coordinated Understanding Of Hydro-Biogeochemical Root Functions In Tropical Forests For Application In Vegetation Models, Daniela F. Cusack, Bradley Christoffersen, Chris M. Smith-Martin, Kelly M. Andersen, Amanda L. Cordeiro, Katrin Fleischer, S. Joseph Wright, Nathaly R. Guerrero-Ramírez, Laynara F. Lugli, Lindsay A. Mcculloch, Mareli Sanchez-Julia, Sarah A. Batterman, Caroline Dallstream, Claire Fortunel, Laura Toro, Lucia Fuchslueger, Michelle Y. Wong, Daniela Yaffar, Joshua B. Fisher, Marie Arnaud, Lee H. Dietterich, Shalom D. Addo-Danso, Oscar J. Valverde-Barrantes, Monique Weemstra, Jing Cheng Ng, Richard J. Norby

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Tropical forest root characteristics and resource acquisition strategies are underrepresented in vegetation and global models, hampering the prediction of forest–climate feedbacks for these carbon-rich ecosystems. Lowland tropical forests often have globally unique combinations of high taxonomic and functional biodiversity, rainfall seasonality, and strongly weathered infertile soils, giving rise to distinct patterns in root traits and functions compared with higher latitude ecosystems. We provide a roadmap for integrating recent advances in our understanding of tropical forest belowground function into vegetation models, focusing on water and nutrient acquisition. We offer comparisons of recent advances in empirical and model understanding of root characteristics …


Extrasynaptic Localization Is Essential For Α5gabaa Receptor Modulation Of Dopamine System Function, Alexandra M. Mccoy, Thomas D. Prevot, Md Yeunus Mian, Dishary Sharmin, Adeeba N. Ahmad, James M. Cook, Etienne L. Sibille, Daniel J. Lodge Feb 2024

Extrasynaptic Localization Is Essential For Α5gabaa Receptor Modulation Of Dopamine System Function, Alexandra M. Mccoy, Thomas D. Prevot, Md Yeunus Mian, Dishary Sharmin, Adeeba N. Ahmad, James M. Cook, Etienne L. Sibille, Daniel J. Lodge

Chemistry Faculty Publications and Presentations

Dopamine system dysfunction, observed in animal models with psychosis-like symptomatology, can be restored by targeting gamma-aminobutyric acid type A receptors (GABAARs) containing the α5, but not α1, subunit in the ventral hippocampus (vHipp). The reason for this discrepancy in efficacy remains elusive; however, one key difference is that gamma-aminobutyric acid type A receptors containing the α1 subunit (α1GABAARs) are primarily located in the synapse, whereas gamma-aminobutyric acid type A receptors containing the α5 subunit (α5GABAARs) are mostly extrasynaptic. To test whether receptor location is responsible for this difference in efficacy, we injected an siRNA into the vHipp to knock down …


Lotic-Sipco2: Adaptation Of An Open-Source Co2 Sensor System And Examination Of Associated Emission Uncertainties Across A Range Of Stream Sizes And Land Uses, Andrew L. Robison, Lauren E. Koenig, Jody D. Potter, Lisle E. Snyder, Christopher W. Hunt, William H. Mcdowell, Wilfred M. Wollheim Feb 2024

Lotic-Sipco2: Adaptation Of An Open-Source Co2 Sensor System And Examination Of Associated Emission Uncertainties Across A Range Of Stream Sizes And Land Uses, Andrew L. Robison, Lauren E. Koenig, Jody D. Potter, Lisle E. Snyder, Christopher W. Hunt, William H. Mcdowell, Wilfred M. Wollheim

Faculty Publications

River networks play a crucial role in the global carbon cycle, as relevant sources of carbon dioxide (CO2) to the atmosphere. Advancements in high-frequency monitoring in aquatic environments have enabled measurement of dissolved CO2 concentration at temporal resolutions essential for studying carbon variability and evasion from these dynamic ecosystems. Here, we describe the adaptation, deployment, and validation of an open-source and relatively low-cost in situ pCO2 sensor system for lotic ecosystems, the lotic-SIPCO2. We tested the lotic-SIPCO2 in 10 streams that spanned a range of land cover and basin size. Key system adaptations for lotic environments included prevention of biofouling, …


Electrocatalytic Asymmetric Nozaki-Hiyama-Kishi Decarboxylative Coupling: Scope, Applications, And Mechanism, Yang Gao, Baiyang Jiang, Nathan C. Friede, Arianne C. Hunter, Dylan G. Boucher, Shelley D. Minteer, Matthew S. Sigman, Sarah E. Reisman, Phil S. Baran Feb 2024

Electrocatalytic Asymmetric Nozaki-Hiyama-Kishi Decarboxylative Coupling: Scope, Applications, And Mechanism, Yang Gao, Baiyang Jiang, Nathan C. Friede, Arianne C. Hunter, Dylan G. Boucher, Shelley D. Minteer, Matthew S. Sigman, Sarah E. Reisman, Phil S. Baran

Chemistry Faculty Research & Creative Works

The first general enantioselective alkyl-Nozaki-Hiyama-Kishi (NHK) coupling reactions are disclosed herein by employing a Cr-electrocatalytic decarboxylative approach. Using easily accessible aliphatic carboxylic acids (via redox-active esters) as alkyl nucleophile synthons, in combination with aldehydes and enabling additives, chiral secondary alcohols are produced in a good yield with high enantioselectivity under mild reductive electrolysis. This reaction, which cannot be mimicked using stoichiometric metal or organic reductants, tolerates a broad range of functional groups and is successfully applied to dramatically simplify the synthesis of multiple medicinally relevant structures and natural products. Mechanistic studies revealed that this asymmetric alkyl e-NHK reaction was enabled …


Papain-Catalyzed Synthesis Of Oligolysine In Low-Water Organic Reaction Media, Lakshmi Priya Ravikrishna, Krishnamurthi Tamilarasan, Vairamani Mariappanadar, Shubhender Kapila, Mathur Rajesh Feb 2024

Papain-Catalyzed Synthesis Of Oligolysine In Low-Water Organic Reaction Media, Lakshmi Priya Ravikrishna, Krishnamurthi Tamilarasan, Vairamani Mariappanadar, Shubhender Kapila, Mathur Rajesh

Chemistry Faculty Research & Creative Works

Oligopeptides of l-lysine have the potential for applications in various scientific and technical areas. The number of residues in polycationic compounds such as oligolysine is also reported to have an effect on its biological properties. Hence, there is a necessity for developing efficient oligolysine synthesis methods where the oligopeptide dispersity can be tailored, along with optimum yield values. The ability of proteases to reverse their proteolytic activity to synthesize peptides has been reported in the literature. However, protease-catalyzed synthesis of oligopeptides of basic amino acids such as lysine in aqueous buffers is hindered by unfavorable thermodynamics. In this work, a …


Purification And Isolation Of Α-Chloro-Β-Lactone Precursor Molecules, Matthew Ellis Feb 2024

Purification And Isolation Of Α-Chloro-Β-Lactone Precursor Molecules, Matthew Ellis

ASPIRE 2024

This research investigates the synthesis of α-chloro-β-lactone molecules, focusing on the production, isolation, and purification of two precursor compounds from chloroacetic acid and substituted benzaldehydes. While multiple methods were explored, including EDC, DIC, and DCC catalysis, DCC proved to be most effective in producing higher yields. However, challenges in purification arose due to the formation of byproducts, particularly with DCC, prompting further investigation for efficient extraction and purification techniques. DCC, however, shows a promising route for α-chloro-β-lactone synthesis, despite purification complexities.


Mesoporous Re0.5ce0.5o2-X Fluorite Electrocatalysts For The Oxygen Evolution Reaction, Sreya Paladugu, Ibrahim Munkaila Abdullahi, Harish Singh, Sam Spinuzzi, Manashi Nath, Katharine Page Feb 2024

Mesoporous Re0.5ce0.5o2-X Fluorite Electrocatalysts For The Oxygen Evolution Reaction, Sreya Paladugu, Ibrahim Munkaila Abdullahi, Harish Singh, Sam Spinuzzi, Manashi Nath, Katharine Page

Chemistry Faculty Research & Creative Works

Developing highly active and stable electrocatalysts for the oxygen evolution reaction (OER) is key to improving the efficiency and practical application of various sustainable energy technologies including water electrolysis, CO2 reduction, and metal air batteries. Here, we use evaporation-induced self-assembly (EISA) to synthesize highly porous fluorite nanocatalysts with a high surface area. In this study, we demonstrate that a 50% rare-earth cation substitution for Ce in the CeO2 fluorite lattice improves the OER activity and stability by introducing oxygen vacancies into the host lattice, which results in a decrease in the adsorption energy of the OH* intermediate in …


Co2 Uptake By Microporous Carbon Aerogels Derived From Polybenzoxazine And Analogous All-Nitrogen Polybenzodiazine Aerogels, Vaibhav A. Edlabadkar, Rushi U. Soni, A. B.M.Shaheen Ud Doulah, Stephen Y. Owusu, Samuel Hackett, Joshua M. Bartels, Nicholas Leventis, Chariklia Sotiriou-Leventis Feb 2024

Co2 Uptake By Microporous Carbon Aerogels Derived From Polybenzoxazine And Analogous All-Nitrogen Polybenzodiazine Aerogels, Vaibhav A. Edlabadkar, Rushi U. Soni, A. B.M.Shaheen Ud Doulah, Stephen Y. Owusu, Samuel Hackett, Joshua M. Bartels, Nicholas Leventis, Chariklia Sotiriou-Leventis

Chemistry Faculty Research & Creative Works

The rapid rise of carbon dioxide in the atmosphere contributes to global warming and ocean acidification. Carbon capture is considered essential for keeping the atmospheric CO2 levels from rising further. This work addresses the question of whether nitrogen or oxygen lining of the surfaces of carbon-based CO2 absorbers is more efficient for CO2 capture. Polybenzodiazine (PBDAZ) aerogels are carbon-aerogel precursors that were prepared recently (2023) as all-nitrogen structural analogues to well-known polybenzoxazine (PBO) aerogels. However, owing to the fact that the carbonization chemistries of both PBO and PBDAZ aerogels require a prior oxidative aromatization step in air …


New Features Of Laboratory-Generated Epfrs From 1,2-Dichlorobenzene (Dcb) And 2‑Monochlorophenol (Mcp), Lavrent Khachatryan, Marwan Y. Rezk, Divine Nde, Farhana Hasan, Slawomir Lomnicki, Dorin Boldor, Robert Cook, Phillip Sprunger, Randall W. Hall, Stephania Cormier Feb 2024

New Features Of Laboratory-Generated Epfrs From 1,2-Dichlorobenzene (Dcb) And 2‑Monochlorophenol (Mcp), Lavrent Khachatryan, Marwan Y. Rezk, Divine Nde, Farhana Hasan, Slawomir Lomnicki, Dorin Boldor, Robert Cook, Phillip Sprunger, Randall W. Hall, Stephania Cormier

Natural Sciences and Mathematics | Faculty Scholarship

The present research is primarily focused on investigating the characteristics of environmentally persistent free radicals (EPFRs) generated from commonly recognized aromatic precursors, namely, 1,2-dichlorobenzene (DCB) and 2- monochlorophenol (MCP), within controlled laboratory conditions at a temperature of 230 °C, termed as DCB230 and MCP230 EPFRs, respectively. An intriguing observation has emerged during the creation of EPFRs from MCP and DCB utilizing a catalyst 5% CuO/SiO2, which was prepared through various methods. A previously proposed mechanism, advanced by Dellinger and colleagues (a conventional model), postulated a positive correlation between the degree of hydroxylation on the catalyst’s surface (higher hydroxylated, HH and …


Pisa Printing Microneedles With Controllable Aqueous Dissolution Kinetics, Aaron Priester, Jimmy Yeng, Yuwei Zhang, Krista Hilmas, Risheng Wang, Anthony J. Convertine Feb 2024

Pisa Printing Microneedles With Controllable Aqueous Dissolution Kinetics, Aaron Priester, Jimmy Yeng, Yuwei Zhang, Krista Hilmas, Risheng Wang, Anthony J. Convertine

Chemistry Faculty Research & Creative Works

This study focused on the development of high-resolution polymeric structures using polymer-induced self-assembly (PISA) printing with commercially available digital light-processing (DLP) printers. Significantly, soluble solids could be 3D-printed using this methodology with controllable aqueous dissolution rates. This was achieved using a highly branched macrochain transfer agent (macro-CTA) containing multiple covalently attached CTA groups. In this work, the use of acrylamide as the self-assembling monomer in isopropyl alcohol was explored with the addition of N-(butoxymethyl)acrylamide to modulate the aqueous dissolution kinetics. PISA-printed microneedles were observed to have feature sizes as small as 27 μm, which was close to the resolution limit …


Determining The Surface PKA Of Perfluorooctanoic Acid, Lila J. Musegades, Owen P. Curtin, Jenée D. Cyran Feb 2024

Determining The Surface PKA Of Perfluorooctanoic Acid, Lila J. Musegades, Owen P. Curtin, Jenée D. Cyran

Chemistry and Biochemistry Faculty Publications and Presentations

Perfluorooctanoic acid (PFOA) is an environmentally prevalent and persistent organic pollutant with toxic and bioaccumulative properties. Despite the known importance of perfluorinated pollutants in the global environment, molecular-level details of the physicochemical behavior of PFOA on aqueous interfaces remain poorly understood. Here, we utilized two surface-specific techniques, vibrational sum frequency generation spectroscopy (SFG) and surface tensiometry, to investigate the pH-induced structural changes of PFOA and octanoic acid (OA) and determined the apparent pKa at the air–water surface. The SFG spectra and surface activity model were investigated over a wide range of pHs. With the surface tension measurements, the …


Unimer Suppression Enables Supersaturated Homopolymer Swollen Micelles With Long-Term Stability After Glassy Entrapment, Eric R. Williams, Christian X. Ruff, Morgan Stefik Feb 2024

Unimer Suppression Enables Supersaturated Homopolymer Swollen Micelles With Long-Term Stability After Glassy Entrapment, Eric R. Williams, Christian X. Ruff, Morgan Stefik

Faculty Publications

Micelle sizes are critical for a range of applications where the simple ability to adjust and lock in specific stable sizes has remained largely elusive. While micelle swelling agents are well-known, their dynamic re-equilibration in solution implies limited stability. Here, a non-equilibrium processing sequence is studied where supersaturated homopolymer swelling is combined with glassy-core (“persistent”) micelles. This path-dependent process was found to sensitively depend on unimer concentration as revealed by DLS, SAXS, and TEM analysis. Here, lower-selectivity solvent combinations led to the formation of unimer-homopolymer aggregates and eventual precipitation, reminiscent of anomalous micellization. In contrast, higher-selectivity solvents enabled supersaturated homopolymer …


Sulfate Enhances The Adsorption And Retention Of Cu(Ii) And Zn(Ii) To Dispersed And Aggregated Iron Oxyhydroxide Nanoparticles, Emma M. Kocik, Abigail Kim, Miranda L. Aiken, Lauren Smith, Christopher S. Kim Feb 2024

Sulfate Enhances The Adsorption And Retention Of Cu(Ii) And Zn(Ii) To Dispersed And Aggregated Iron Oxyhydroxide Nanoparticles, Emma M. Kocik, Abigail Kim, Miranda L. Aiken, Lauren Smith, Christopher S. Kim

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The adsorption and retention of metal ions to nanoscale iron (hydr)oxides in aqueous systems is significantly influenced by prevailing environmental conditions. We examined the influence of sulfate, the second most common anion in seawater that is present in many other natural aquatic systems, on the adsorption and retention of Cu(II) and Zn(II) to synthetic iron oxyhydroxide nanoparticles (NPs) and their aggregates. Batch uptake experiments with monodisperse NPs and NPs aggregated by changes in pH, ionic strength, and temperature were conducted over sulfate concentrations ranging from 0 to 0.30 M. The introduction of 0.03 M sulfate significantly increased the initial adsorption …


Computational Study Of Binding Of Oseltamivir To Neuraminidase Mutants Of Influenza A Virus, Muhammad Arba, Sri Wahyuli, Setyanto Tri Wahyudi, Amir Karton, Chun Wu Feb 2024

Computational Study Of Binding Of Oseltamivir To Neuraminidase Mutants Of Influenza A Virus, Muhammad Arba, Sri Wahyuli, Setyanto Tri Wahyudi, Amir Karton, Chun Wu

Faculty Scholarship for the College of Science & Mathematics

Oseltamivir (OTV), which targets the neuraminidase (NA) of Influenza A virus (IAV), has been reported to develop resistance. Here, we performed a computational study on the binding modes of OTV in the wild-type and popular mutants of IAV NA (E119A, E119D, E119G, H274Y, I117T, I117V, I117V-E119A, K150N, N294S, R292K, V116A, and Y252H). The Arg118, Glu119, Asp151, Arg152, Glu276, Arg292, and Arg371 were identified as crucial interacting residues with the drug. The energy decomposition analysis showed that with few exceptions, the dispersion interaction is the dominant interaction, followed by the charge-transfer and polarization interactions. The affinities for OTV were greatly reduced …


Maximizing Charge Dynamics In Znin2s4/Cn Van Der Waals Heterojunction For Optimal Hydrogen Production From Photoreforming Of Glucose, Jinqiang Zhang, Xinyuan Xu, Lei Shi, Huayang Zhang, Shaobin Wang, Hongqi Sun Feb 2024

Maximizing Charge Dynamics In Znin2s4/Cn Van Der Waals Heterojunction For Optimal Hydrogen Production From Photoreforming Of Glucose, Jinqiang Zhang, Xinyuan Xu, Lei Shi, Huayang Zhang, Shaobin Wang, Hongqi Sun

Research outputs 2022 to 2026

Biomass photoreforming stands out as a promising avenue for green hydrogen, leveraging solar energy for the generation and transformation of clean and renewable energy resources. The pursuit of efficient photocatalysts is motivated by the unsatisfied hydrogen evolution performance arising from the complex and stubborn structure of biomass. Herein, we loaded 2-dimensional (2D) ZnIn2S4 onto 2D carbon nitride nanosheets, resulting in the formation of Van der Waals (VDW) heterojunctions (ZIS/CN). Band structure and morphology of CN were rationally tailored through precursor engineering to effectively magnify interfacial internal electric field and minimize diffusion pathway within the VDW heterostructure, realizing optimal charge dynamics …


Unusual Catalytic Strategy By Non-Heme Fe(Ii)/2-Oxoglutarate-Dependent Aspartyl Hydroxylase Asph, Anandhu Krishnan, Sodiq Waheed, Ann Varghese, Fathima Hameed Cherilakkudy, Christopher J. Schofield, Tatyana G. Karabencheva-Christova Feb 2024

Unusual Catalytic Strategy By Non-Heme Fe(Ii)/2-Oxoglutarate-Dependent Aspartyl Hydroxylase Asph, Anandhu Krishnan, Sodiq Waheed, Ann Varghese, Fathima Hameed Cherilakkudy, Christopher J. Schofield, Tatyana G. Karabencheva-Christova

Michigan Tech Publications, Part 2

Biocatalytic C-H oxidation reactions are of important synthetic utility, provide a sustainable route for selective synthesis of important organic molecules, and are an integral part of fundamental cell processes. The multidomain non-heme Fe(ii)/2-oxoglutarate (2OG) dependent oxygenase AspH catalyzes stereoselective (3R)-hydroxylation of aspartyl- and asparaginyl-residues. Unusually, compared to other 2OG hydroxylases, crystallography has shown that AspH lacks the carboxylate residue of the characteristic two-His-one-Asp/Glu Fe-binding triad. Instead, AspH has a water molecule that coordinates Fe(ii) in the coordination position usually occupied by the Asp/Glu carboxylate. Molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) studies reveal that the iron coordinating water is …


New Discoveries On Protein Recruitment And Regulation During The Early Stages Of The Dna Damage Response Pathways, Kelly Waters, Donald E. Spratt Feb 2024

New Discoveries On Protein Recruitment And Regulation During The Early Stages Of The Dna Damage Response Pathways, Kelly Waters, Donald E. Spratt

Chemistry

Maintaining genomic stability and properly repairing damaged DNA is essential to staying healthy and preserving cellular homeostasis. The five major pathways involved in repairing eukaryotic DNA include base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), non-homologous end joining (NHEJ), and homologous recombination (HR). When these pathways do not properly repair damaged DNA, genomic stability is compromised and can contribute to diseases such as cancer. It is essential that the causes of DNA damage and the consequent repair pathways are fully understood, yet the initial recruitment and regulation of DNA damage response proteins remains unclear. In this review, …


An Itpa Enzyme With Improved Substrate Selectivity, Nicholas E. Burgis, Kandise Vanwormer, Devin Robbins, Jonathan Smith Feb 2024

An Itpa Enzyme With Improved Substrate Selectivity, Nicholas E. Burgis, Kandise Vanwormer, Devin Robbins, Jonathan Smith

Chemistry and Biochemistry Faculty Publications

Recent clinical data have identified infant patients with lethal ITPA deficiencies. ITPA is known to modulate ITP concentrations in cells and has a critical function in neural development which is not understood. Polymorphism of the ITPA gene affects outcomes for both ribavirin and thiopurine based therapies and nearly one third of the human population is thought to harbor ITPA polymorphism. In a previous site-directed mutagenesis alanine screen of the ITPA substrate selectivity pocket, we identified the ITPA mutant, E22A, as a gain-of function mutant with enhanced ITP hydrolysis activity. Here we report a rational enzyme engineering experiment to investigate the …