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Articles 3061 - 3090 of 34537

Full-Text Articles in Physical Sciences and Mathematics

Progress Of Pt-Based Catalysts In Proton-Exchange Membrane Fuel Cells: A Review, Long Huang, Hai-Chao Xu, Bi Jing, Qiu-Xia Li, Wei Yi, Shi-Gang Sun Jan 2022

Progress Of Pt-Based Catalysts In Proton-Exchange Membrane Fuel Cells: A Review, Long Huang, Hai-Chao Xu, Bi Jing, Qiu-Xia Li, Wei Yi, Shi-Gang Sun

Journal of Electrochemistry

Fuel cells are energy conversion devices that convert chemical energy directly into electricity. It has the advantages of high energy density, high utilization efficiency of fuel, clean and noiseless during working. Among all kinds of fuel cells, proton exchange membrane fuel cells (PEMFCs) are most popular since PEMFCs function at near ambient temperature, while their power densities are higher than those of other fuel cells. Currently, Pt-based nanomaterials are still the unreplaceable catalysts in commercialized PEMFCs. The lack of low-cost and high-performance cathode catalysts is still one of key factors that hampers the commercialization of PEMFCs. In this review, the …


A High-Performance Continuous-Flow Mea Reactor For Electroreduction Co2 To Formate, Pei-Xuan Liu, Lu-Wei Peng, Rui-Nan He, Lu-Lu Li, Jin-Li Qiao Jan 2022

A High-Performance Continuous-Flow Mea Reactor For Electroreduction Co2 To Formate, Pei-Xuan Liu, Lu-Wei Peng, Rui-Nan He, Lu-Lu Li, Jin-Li Qiao

Journal of Electrochemistry

The electrochemical carbon dioxide reduction reaction (CO2RR) is a promising approach to produce liquid fuels and industrial chemicals by utilizing intermittent renewable electricity for mitigating environmental problems. However, the traditional H-type reactor seriously limits the electrochemical performance of CO2RR due to the low CO2 solubility in electrolyte, and high ohmic resistance caused by the large distance between two electrodes, which is unbeneficial for industrial application. Herein, we demonstrated a high-performance continuous flow membranes electrode assembly (MEA) reactor based on a self-growing Cu/Sn bimetallic electrocatalyst in 0.5 mol·L-1 KHCO3 for converting CO2 to …


A Flexible Enzymeless Glucose Sensor Via Electrodepositing 3d Flower-Like Cos Onto Self-Supporting Graphene Tape Electrode, Jiang Li, Zuo-Peng Li, Yun-Feng Bai, Su-Xing Luo, Yong Guo, Ya-Yan Bao, Rong Li, Hai-Yan Liu, Feng Feng Jan 2022

A Flexible Enzymeless Glucose Sensor Via Electrodepositing 3d Flower-Like Cos Onto Self-Supporting Graphene Tape Electrode, Jiang Li, Zuo-Peng Li, Yun-Feng Bai, Su-Xing Luo, Yong Guo, Ya-Yan Bao, Rong Li, Hai-Yan Liu, Feng Feng

Journal of Electrochemistry

Three-dimensional (3D) nanostructural Flower-like cobalt sulfide (CoS) on flexible self-supporting graphene tape electrode (GTE) with remarkably electrocatalytic activity toward glucose was successfully prepared by electrodeposition. Structural characterizations revealed that the electrodeposited CoS was highly dispersed on GTE as an active material. The fabricated binder-free and self-standing CoS/GTE shows a good linear response in the range of 0.025 ~ 1.0 mmol·L-1, reaching a high glucose sensitivity value of 323.3 μA·(mmol·L -1)-1·cm-2 and a low detection limit of 8.5 μmol·L -1 (S/N = 3). Moreover, the as-prepared sensor was well applied for glucose …


Oxidative Efficiency Of Ozonation Coupled With Electrolysis For Treatment Of Acid Wastewater, Ze-You Hu, Feng-Yun Xiang, Ji-Qiang Mao, Ya-Lei Ding, Shao-Ping Tong Jan 2022

Oxidative Efficiency Of Ozonation Coupled With Electrolysis For Treatment Of Acid Wastewater, Ze-You Hu, Feng-Yun Xiang, Ji-Qiang Mao, Ya-Lei Ding, Shao-Ping Tong

Journal of Electrochemistry

Establishment of an ozone-based advanced oxidation process (AOPs-O3) for effective treatment of acid wastewater is an important and difficult task. The process of ozonation coupled with electrolysis (electrolysis-ozonation, E-O3) has been reported to effectively degrade pollutants in neutral solution. We studied the efficiency of E-O3 for degradation of acetic acid (HAc, an ozone inert chemical) in acid solution and found that E-O3 had high oxidative efficiency at pH less than 3. For example, 52.2% of 100 mg·L-1 HAc could be removed by E-O3 in 120 min at pH 1.0, but only 2.2% …


Advances Of Phosphide Promoter Assisted Pt Based Catalyst For Electrooxidation Of Methanol, Meng Li, Li-Gang Feng Jan 2022

Advances Of Phosphide Promoter Assisted Pt Based Catalyst For Electrooxidation Of Methanol, Meng Li, Li-Gang Feng

Journal of Electrochemistry

Transition metal phosphide (TMP), as an ideal catalytic promoter in methanol fuel oxidation, has received increased attention because of its multifunctional active sites, tunable structure and composition, as well as unique physical and chemical properties and efficient multi-composition synergistic effect. Some advances have been made for this catalyst system recently. In the current review, the research progresses of transition metal phosphides (TMPs) in the assisted electrooxidation of methanol including the catalysts fabrication and their performance evaluation for methanol oxidation are reviewed. The promotion effect of TMPs has been firstly presented and the catalyst systems based on the different metal centers …


Synthesis Of Lithium-Rich Manganese-Based Layered Cathode Materials And Study On Its Structural Evolution Of First Cycle Overcharge, Chen-Xu Luo, Chen-Guang Shi, Zhi-Yuan Yu, Ling Huang, Shi-Gang Sun Jan 2022

Synthesis Of Lithium-Rich Manganese-Based Layered Cathode Materials And Study On Its Structural Evolution Of First Cycle Overcharge, Chen-Xu Luo, Chen-Guang Shi, Zhi-Yuan Yu, Ling Huang, Shi-Gang Sun

Journal of Electrochemistry

Lithium-rich manganese-based cathode materials have become one of promising cathode materials due to their low cost and large discharge specific capacity exceeding 250 mAh·g-1. However, their problems such as low coulombic efficiency of first cycle and apparent voltage decay influence commercialization process. The high charging voltage will cause instability of structure and increase the hidden danger of the battery. Therefore, structural evolution of first cycle at higher voltage needs to be further studied. In this work, the precursor was synthesized by the co-precipitation method, and the lithium-rich manganese-based layered cathode materials were prepared by lithium-mixed and high-temperature sintering, …


Effects Of Long-Term Fluoride Exposure Are Associated With Oxidative Biochemistry Impairment And Global Proteomic Modulation, But Not Genotoxicity, In Parotid Glands Of Mice, Giza Hellen Nonato Mirandai, Leidiane Alencar De Oliveira Lima, Leonardo Oliveira Bittencourt, Sa´Vio Monteiro Dos Santos, Michel Platini Caldas De Souza, Lygia Sega Nogueira, Edivaldo Herculano Corrêa De Oliveira, Marta Chagas Monteir, Aline Dionizio, Aline Lima Leite, Juliano Pelim Pessan, Juliano Pelim Pessan, Marı´Lia Afonso Rabelo Buzalaf, Rafael Rodrigues Limai Jan 2022

Effects Of Long-Term Fluoride Exposure Are Associated With Oxidative Biochemistry Impairment And Global Proteomic Modulation, But Not Genotoxicity, In Parotid Glands Of Mice, Giza Hellen Nonato Mirandai, Leidiane Alencar De Oliveira Lima, Leonardo Oliveira Bittencourt, Sa´Vio Monteiro Dos Santos, Michel Platini Caldas De Souza, Lygia Sega Nogueira, Edivaldo Herculano Corrêa De Oliveira, Marta Chagas Monteir, Aline Dionizio, Aline Lima Leite, Juliano Pelim Pessan, Juliano Pelim Pessan, Marı´Lia Afonso Rabelo Buzalaf, Rafael Rodrigues Limai

Chemistry Department: Faculty Publications

Fluoride has become widely used in dentistry because of its effectiveness in caries control. However, evidence indicates that excessive intake interferes with the metabolic processes of different tissues. Thus, this study aimed to investigate the effects of long-term exposure to F on the parotid salivary gland of mice, from the analysis of oxidative, proteomic and genotoxic parameters.

The animals received deionized water containing 0, 10 or 50 mg/L of F, as sodium fluoride, for 60 days. After, parotid glands were collected for analysis of oxidative biochemistry, global proteomic profile, genotoxicity assessment and histopathological analyses.

The results revealed that exposure to …


Identification Of Alternative Protein Targets Of Glutamate-Ureido-Lysine Associated With Psma Tracer Uptake In Prostate Cancer Cells, Martin K. Bakht, John J. Hayward, Farsheed Shahbazi-Raz, Magdalena Skubal, Ryo Tamura, Keith F. Stringer, Daniel Meister, Varadha Balaji Venkadakrishnan, Hui Xue, Adam Pillon, Mathew Stover, Adam Tronchin, Bre Anne Fifield, Lavleen Mader, Sheng Yu Ku, Gi Jeong Cheon, Keon Wook Kang, Yuzhuo Wang, Xuesen Dong, Himisha Beltran, Jan Grimm, Lis A. Porter, John F. Trant Jan 2022

Identification Of Alternative Protein Targets Of Glutamate-Ureido-Lysine Associated With Psma Tracer Uptake In Prostate Cancer Cells, Martin K. Bakht, John J. Hayward, Farsheed Shahbazi-Raz, Magdalena Skubal, Ryo Tamura, Keith F. Stringer, Daniel Meister, Varadha Balaji Venkadakrishnan, Hui Xue, Adam Pillon, Mathew Stover, Adam Tronchin, Bre Anne Fifield, Lavleen Mader, Sheng Yu Ku, Gi Jeong Cheon, Keon Wook Kang, Yuzhuo Wang, Xuesen Dong, Himisha Beltran, Jan Grimm, Lis A. Porter, John F. Trant

Chemistry and Biochemistry Publications

Prostate-specific membrane antigen (PSMA) is highly overexpressed in most prostate cancers and is clinically visualized using PSMA-specific probes incorporating glutamate-ureido-lysine (GUL). PSMA is effectively absent from certain high-mortality, treatment-resistant subsets of prostate cancers, such as neuroendocrine prostate cancer (NEPC); however, GUL-based PSMA tracers are still reported to have the potential to identify NEPC metastatic tumors. These probes may bind unknown proteins associated with PSMA-suppressed cancers. We have identified the up-regulation of PSMA-like aminopeptidase NAALADaseL and the metabotropic glutamate receptors (mGluRs) in PSMA-suppressed prostate cancers and find that their expression levels inversely correlate with PSMA expression and are associated with GUL-based …


Evidence For A Semisolid Phase State Of Aerosols And Droplets Relevant To The Airborne And Surface Survival Of Pathogens, Erik Huynh, Anna Olinger, David Woolley, R. K. Kohli, J. M. Choczynski, J. F. Davies, K. Lin, L. C. Marr, Ryan D. Davis Jan 2022

Evidence For A Semisolid Phase State Of Aerosols And Droplets Relevant To The Airborne And Surface Survival Of Pathogens, Erik Huynh, Anna Olinger, David Woolley, R. K. Kohli, J. M. Choczynski, J. F. Davies, K. Lin, L. C. Marr, Ryan D. Davis

Chemistry Faculty Research

The phase state of respiratory aerosols and droplets has been linked to the humidity-dependent survival of pathogens such as SARS-CoV-2. To inform strategies to mitigate the spread of infectious disease, it is thus necessary to understand the humidity-dependent phase changes associated with the particles in which pathogens are suspended. Here, we study phase changes of levitated aerosols and droplets composed of model respiratory compounds (salt and protein) and growth media (organic-inorganic mixtures commonly used in studies of pathogen survival) with decreasing relative humidity (RH). Efflorescence was suppressed in many particle compositions and thus unlikely to fully account for the humidity-dependent …


Resolving The Three-Dimensional Rotational And Translational Dynamics Of Single Molecules Using Radially And Azimuthally Polarized Fluorescence, Oumeng Zhang, Weiyan Zhou, Jin Lu, Tingting Wu, Matthew D. Lew Jan 2022

Resolving The Three-Dimensional Rotational And Translational Dynamics Of Single Molecules Using Radially And Azimuthally Polarized Fluorescence, Oumeng Zhang, Weiyan Zhou, Jin Lu, Tingting Wu, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

We report a radially and azimuthally polarized (raPol) microscope for high detection and estimation performance in single-molecule orientation-localization microscopy (SMOLM). With 5000 photons detected from Nile red (NR) transiently bound within supported lipid bilayers (SLBs), raPol SMOLM achieves 2.9 nm localization precision, 1.5° orientation precision, and 0.17 sr precision in estimating rotational wobble. Within DPPC SLBs, SMOLM imaging reveals the existence of randomly oriented binding pockets that prevent NR from freely exploring all orientations. Treating the SLBs with cholesterol-loaded methyl-β-cyclodextrin (MβCD-chol) causes NR’s orientational diffusion to be dramatically reduced, but curiously NR’s median lateral displacements drastically increase from 20.8 to …


Directions For The Development Of Personal Subsidiary Farms And Increasing Sources Of Income In The Future, Yakupov Kabil Jan 2022

Directions For The Development Of Personal Subsidiary Farms And Increasing Sources Of Income In The Future, Yakupov Kabil

Karakalpak Scientific Journal

This article discusses the features of the development of personal subsidiary farms in modern conditions, defines their functions in the agrarian economy and in the life of society as a whole. Modern agrarian policy provides for the development of various forms of management, including personal subsidiary farms. Personal subsidiary farms are an organic part of the agricultural sectors and make a significant contribution to solving the food problem of the country. The provision of the population with food products is carried out by personal subsidiary farms through their own consumption, as well as the sale of surplus products.


Near-Infrared Unsymmetrical Squaraine Core-Based Sensitizers For Co-Sensitized High-Photocurrent Dye-Sensitized Solar Cells, Jonathon Watson, Roberta R. Rodrigues, Jared H. Delcamp Jan 2022

Near-Infrared Unsymmetrical Squaraine Core-Based Sensitizers For Co-Sensitized High-Photocurrent Dye-Sensitized Solar Cells, Jonathon Watson, Roberta R. Rodrigues, Jared H. Delcamp

Faculty and Student Publications

Increased conversion of near-infrared (NIR) photons to electricity is needed to improve dye-sensitized solar cells (DSCs). Here, we report two squaraine dyes (RR13 and RR14) with unsymmetrical cores as NIR dyes in DSCs. Both dyes feature a conjugated indolizine donor with an indoline donor on the opposite side of the squaraine core. The dyes are studied via absorption spectroscopy, computational interrogation, and electrochemical analysis. The use of the strongly donating indolizine donor results in NIR photon-to-current conversion extending beyond 800 nm on TiO2 in DSC devices. The DSC devices were characterized by current-voltage curves, incident photon-to-current conversion efficiency measurements, and …


Materials And Methodologies For Spectroscopic And Optical Analytical Applications In Cultural Heritage Conservation Science, Lyndsay Nichole Kissell Jan 2022

Materials And Methodologies For Spectroscopic And Optical Analytical Applications In Cultural Heritage Conservation Science, Lyndsay Nichole Kissell

Dissertations and Theses

The field of conservation science falls in the intersection of science and art. The work of conservation scientists may include any single subdiscipline of chemistry, though it is most commonly a highly interdisciplinary field taking skills from analytical, organic, and inorganic chemistry, as well as surface and materials science. The aims of conservation scientists are to answer questions about the production and aging of material cultural heritage. Knowing the materials used by an artist can lead to insight about the intentions of the object and knowing how those materials degrade will enable the use of preventative measures to ensure the …


Flexible Bielectrode-Based Highly Sensitive Triboelectric Motion Sensor: A Sustainable And Smart Electronic Material, Damian Zamora, Abu Masa Abdullah, Alejandro Flores, Haimanti Majumder, Muhtasim Ul Karim Sadaf, Bahareh Azimi, Serena Danti, M. Jasim Uddin Jan 2022

Flexible Bielectrode-Based Highly Sensitive Triboelectric Motion Sensor: A Sustainable And Smart Electronic Material, Damian Zamora, Abu Masa Abdullah, Alejandro Flores, Haimanti Majumder, Muhtasim Ul Karim Sadaf, Bahareh Azimi, Serena Danti, M. Jasim Uddin

Chemistry Faculty Publications and Presentations

The self-powered and autonomous sensors are incredibly important in advanced engineering, especially defence science. The increasing necessity of simple and smart electronics requires to be sustainably flexible, wearable, and waterproof. Triboelectricity has been a widely used mechanism for motion sensing nowadays. Almost all devices based on triboelectricity require contact between two surfaces. Herein, a touchless triboelectric motion sensor for human motion sensing and movement monitoring is developed. The device was primarily fabricated using simple latex (cis-1,4-polyisoprene) structures and copper (electrode materials), which make it a very cost-effective device for sensory applications. The device is tested with specimens of different areas …


Methanol Decomposition On Ni(111) And O/Ni(111), Henrik Öström, Bingjie Zhang, Tiffany Vallejo, Bryn Merrill, Jeremy Huang, Jerry Larue Jan 2022

Methanol Decomposition On Ni(111) And O/Ni(111), Henrik Öström, Bingjie Zhang, Tiffany Vallejo, Bryn Merrill, Jeremy Huang, Jerry Larue

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Methanol decomposition on Ni(111) surfaces has been studied in the presence and absence of oxygen using temperature-programmed desorption and temperature-dependent sum frequency generation spectroscopy. Under both conditions the C–H and O–H bonds break, forming carbon monoxide and atomic hydrogen on the surface. No C–O bond scission was observed, limiting the number of reaction pathways. The O–H bonds break first (>150 K), forming surface methoxy, followed by C–H bond breakage (>250 K). All atomic hydrogen desorbs from the surface as H2 through H+H recombinative desorption. H2 desorbs at a higher temperature in the presence of oxygen (>300 K) …


One-Pot Conversion Of Carboxylic Acids To Aldehydes, Hannah Khan, Michael Nantz, Saurin Sutaria Jan 2022

One-Pot Conversion Of Carboxylic Acids To Aldehydes, Hannah Khan, Michael Nantz, Saurin Sutaria

Posters-at-the-Capitol

There are many different ways to convert a carboxylic text acid to an aldehyde. A common way to accomplish this transformation is to use multiple steps (e.g., reduction of the carboxylic acid to the corresponding alcohol followed by selective oxidation to the aldehyde). Our success in reducing the diacid muconic acid (1) to muconaldehyde (4) in a relatively mild, one-pot process has led us to examine whether the method can be expanded to other carboxylic acids. We report here our findings using benzoic acid as a representative substrate.


Evolution Of Microscopic Heterogeneity And Dynamics In Choline Chloride-Based Deep Eutectic Solvents, Stephanie Spittle, Derrick Poe, Brain Doherty, Charles Kolodziej, Luke Heroux, Md Ashraful Haque, Henry Squire, Tyler Cosby, Yong Zhang, Carla Fraenza, Sahana Bhattacharyya, Madhusudan Tyagi, Jing Peng, Ramez A. Elgammal, Thomas Zawodzinski, Mark Tuckerman, Steve Greenbaum, Burcu Gurkan, Clemens Burda, Mark Dadmun, Edward J. Maginn, Joshua Sangoro Jan 2022

Evolution Of Microscopic Heterogeneity And Dynamics In Choline Chloride-Based Deep Eutectic Solvents, Stephanie Spittle, Derrick Poe, Brain Doherty, Charles Kolodziej, Luke Heroux, Md Ashraful Haque, Henry Squire, Tyler Cosby, Yong Zhang, Carla Fraenza, Sahana Bhattacharyya, Madhusudan Tyagi, Jing Peng, Ramez A. Elgammal, Thomas Zawodzinski, Mark Tuckerman, Steve Greenbaum, Burcu Gurkan, Clemens Burda, Mark Dadmun, Edward J. Maginn, Joshua Sangoro

Publications and Research

Deep eutectic solvents (DESs) are an emerging class of non-aqueous solvents that are potentially scalable, easy to prepare and functionalize for many applications ranging from biomass processing to energy storage technologies. Predictive understanding of the fundamental correlations between local structure and macroscopic properties is needed to exploit the large design space and tunability of DESs for specific applications. Here, we employ a range of computational and experimental techniques that span length-scales from molecular to macroscopic and timescales from picoseconds to seconds to study the evolution of structure and dynamics in model DESs, namely Glyceline and Ethaline, starting from the parent …


Wastewater-Based Estimation Of Substances Discharged At The Rest Areas Along The State Highways In Kentucky, Katherine E. Gray, Eugene Shin, Tyler Whitt, Andrew Windhorst, Houston Hampton, Chris Delcher, Bikram Subedi Jan 2022

Wastewater-Based Estimation Of Substances Discharged At The Rest Areas Along The State Highways In Kentucky, Katherine E. Gray, Eugene Shin, Tyler Whitt, Andrew Windhorst, Houston Hampton, Chris Delcher, Bikram Subedi

Posters-at-the-Capitol

The availability of licit and illicit stimulants and its adverse consequences on public health has emerged as a major drug threat to communities in the United States. Despite several drug-involved traffic incidents along the interstate highways, this report represents the first comprehensive and quantitative report of drugs discharged at the rest areas along the interstate highways. In this National Institute of Justice-funded study, the amount of several discharged drugs focusing on stimulants but also including opioids and prescription antipsychotics are being measured in raw wastewater collected from five rest areas and a truck servicing facility using a state-of-the-art mass …


Iron Dysregulation In Covid-19 And Reciprocal Evolution Of Sars-Cov-2: Natura Nihil Frustra Facit, Yash Gupta, Dawid Maciorowski, Brian Medernach, Daniel P. Becker Ph.D., Ravi Durvasula, Claudia R. Libertin, Prakasha Kempaiah Jan 2022

Iron Dysregulation In Covid-19 And Reciprocal Evolution Of Sars-Cov-2: Natura Nihil Frustra Facit, Yash Gupta, Dawid Maciorowski, Brian Medernach, Daniel P. Becker Ph.D., Ravi Durvasula, Claudia R. Libertin, Prakasha Kempaiah

Chemistry: Faculty Publications and Other Works

After more than a year of the COVID-19 pandemic, SARS-CoV-2 infection rates with newer variants continue to devastate much of the world. Global healthcare systems are overwhelmed with high positive patient numbers. Silent hypoxia accompanied by rapid deterioration and some cases with septic shock is responsible for COVID-19 mortality in many hospitalized patients. There is an urgent need to further understand the relationships and interplay with human host components during pathogenesis and immune evasion strategies. Currently, acquired immunity through vaccination or prior infection usually provides sufficient protection against the emerging variants of SARS-CoV-2 except Omicron variant requiring recent booster. New …


Radical-Initiated Brown Carbon Formation In Sunlit Carbonyl–Amine–Ammonium Sulfate Mixtures And Aqueous Aerosol Particles, Natalie G. Jimenez, Kyle D. Sharp, Tobin Gramyk, Duncan Z. Ugland, Matthew-Khoa Tran, Antonio Rojas, Michael A. Rafla, Devoun Stewart, Melissa M. Galloway, Peng Lin, Alexander Laskin, Mathieu Cazaunau, Edouard Pangui, Jean-François Doussin, David O. De Haan Jan 2022

Radical-Initiated Brown Carbon Formation In Sunlit Carbonyl–Amine–Ammonium Sulfate Mixtures And Aqueous Aerosol Particles, Natalie G. Jimenez, Kyle D. Sharp, Tobin Gramyk, Duncan Z. Ugland, Matthew-Khoa Tran, Antonio Rojas, Michael A. Rafla, Devoun Stewart, Melissa M. Galloway, Peng Lin, Alexander Laskin, Mathieu Cazaunau, Edouard Pangui, Jean-François Doussin, David O. De Haan

Chemistry and Biochemistry: Faculty Scholarship

Brown carbon (BrC) formed from glyoxal+ammonium sulfate (AS) and methylglyoxal+AS reactions photobleaches quickly, leading to the assumption that BrC formed overnight by Maillard reactions will be rapidly destroyed at sunrise. Here, we tested this assumption by reacting glyoxal, methylglyoxal, glycolaldehyde, or hydroxyacetone in aqueous mixtures with reduced nitrogen species at pH 4–5 in the dark and in sunlight (>350 nm) for at least 10 h. The absorption of fresh carbonyl+AS mixtures decreased when exposed to sunlight, and no BrC formed, as expected from previous work. However, the addition of amines (either methylamine or glycine) allowed BrC to form in …


Synthesis Of Methanediol [Ch2(Oh)2]: The Simplest Geminal Diol, Cheng Zhu, N. Fabian Kleimeier, Andrew M. Turner, Santosh K. Singh, Ryan C. Fortenberry, Ralf I. Kaiser Jan 2022

Synthesis Of Methanediol [Ch2(Oh)2]: The Simplest Geminal Diol, Cheng Zhu, N. Fabian Kleimeier, Andrew M. Turner, Santosh K. Singh, Ryan C. Fortenberry, Ralf I. Kaiser

Faculty and Student Publications

Geminal diols—organic molecules carrying two hydroxyl groups at the same carbon atom—have been recognized as key reactive intermediates by the physical (organic) chemistry and atmospheric science communities as fundamental transients in the aerosol cycle and in the atmospheric ozonolysis reaction sequence. Anticipating short lifetimes and their tendency to fragment to water plus the aldehyde or ketone, free geminal diols represent one of the most elusive classes of organic reactive intermediates. Here, we afford an exceptional glance into the preparation of the previously elusive methanediol [CH2(OH)2] transient—the simplest geminal diol—via energetic processing of low-temperature methanol–oxygen ices. Methanediol was identified in the …


Investigation Of Metastable Low Dimensional Halometallates, Navindra Keerthisinghe, Matthew S. Christian, Anna A. Berseneva, Gregory Morrison, Vladislav V. Klepov, Mark D. Smith, Hans Conrad Zur Loye Jan 2022

Investigation Of Metastable Low Dimensional Halometallates, Navindra Keerthisinghe, Matthew S. Christian, Anna A. Berseneva, Gregory Morrison, Vladislav V. Klepov, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

The solvothermal synthesis, structure determination and optical characterization of five new metastable halometallate compounds, [1,10-phenH][Pb3.5I8] (1), [1,10-phenH2][Pb5I12]·(H2O) (2), [1,10-phen][Pb2I4] (3), [1,10-phen]2[Pb5Br10] (4) and [1,10-phenH][SbI4]·(H2O) (5), are reported. The materials exhibit rich structural diversity and exhibit structural dimensionalities that include 1D chains, 2D sheets and 3D frameworks. The optical spectra of these materials are consistent with bandgaps ranging from 2.70 to 3.44 eV. We show …


Identifying Membrane Lateral Organization By Contrast-Matched Small Angle Neutron Scattering, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Frederick A. Heberle, Drew Marquardt Jan 2022

Identifying Membrane Lateral Organization By Contrast-Matched Small Angle Neutron Scattering, Mitchell Dipasquale, Michael H.L. Nguyen, Stuart R. Castillo, Frederick A. Heberle, Drew Marquardt

Chemistry and Biochemistry Publications

Lipid domains in model membranes are routinely studied to provide insight into the physical interactions that drive raft formation in cellular membranes. Using small angle neutron scattering, contrast-matching techniques enable the detection of lipid domains ranging from tens to hundreds of nanometers which are not accessible to other techniques without the use of extrinsic probes. Here, we describe a probe-free experimental approach and model-free analysis to identify lipid domains in freely floating vesicles of ternary phase separating lipid mixtures.


Rhodium-Catalyzed Decarbonylation Of Aroyl Chlorides, Wiktoria M. Koza Jan 2022

Rhodium-Catalyzed Decarbonylation Of Aroyl Chlorides, Wiktoria M. Koza

Dissertations

The development of efficient strategies for the synthesis of aryl–halogen bonds is highly desirable due to the prevalence of these moieties in pharmaceuticals, agrochemicals, and organic synthesis. Although there are numerous applications of aryl chlorides in chemistry, an efficient strategy for the preparation of these molecules is underdeveloped. Transition metal-catalyzed decarbonylation provides an efficient and selective approach for aryl–halogen bond formation. There has been significant progress in the development of new decarbonylation strategies, particularly involving aldehydes for the synthesis of new carbon–hydrogen (C–H) bonds or for cross-coupling reactions. However, transition metal-catalyzed decarbonylation methods for carbon–halogen (C–X) bond formation have been …


Ultrafast Dynamics Of Nitro−Nitrite Rearrangement And Dissociation In Nitromethane Cation, Mi'kayla D. Word, Hugo Andres Lopez Pena, Derrick Ampadu Boateng, Shane L. Mcpherson, Gennady L. Gutsev, Lavrenty Gutsev, Ka Un Lao, Katharine M. Tibbetts Jan 2022

Ultrafast Dynamics Of Nitro−Nitrite Rearrangement And Dissociation In Nitromethane Cation, Mi'kayla D. Word, Hugo Andres Lopez Pena, Derrick Ampadu Boateng, Shane L. Mcpherson, Gennady L. Gutsev, Lavrenty Gutsev, Ka Un Lao, Katharine M. Tibbetts

Chemistry Publications

We report new insights into the ultrafast rearrange- ment and dissociation dynamics of nitromethane cation (NM+) using pump−probe measurements, electronic structure calculations, and ab initio molecular dynamics simulations. The “roaming” nitro−nitrite rearrangement (NNR) pathway involving large- amplitude atomic motion, which has been previously described for neutral nitromethane, is demonstrated for NM+. Excess energy resulting from initial population of the electronically excited D2 state of NM+ upon strong-field ionization provides the necessary energy to initiate NNR and subsequent dissociation into NO+. Both pump−probe measurements and molecular dynamics simulations are consistent with the completion of NNR within 500 fs of ionization with …


Generation Of Nanomaterials By Reactive Laser Synthesis In Liquid, Laysa M. Frias Batista, Ashish B. Nag, Victoria K. Meader, Katharine M. Tibbetts Jan 2022

Generation Of Nanomaterials By Reactive Laser Synthesis In Liquid, Laysa M. Frias Batista, Ashish B. Nag, Victoria K. Meader, Katharine M. Tibbetts

Chemistry Publications

Nanomaterials with tailored structures and surface chemistry are in high demand, as these materials play increasingly important roles in biology, catalysis, energy storage, and manu- facturing. Their heightened demand has attracted attention towards the development of syn- thesis routes, particularly, laser-synthesis techniques. These efforts drove the refinement of laser ablation in liquid (LAL) and related methods over the past two decades, and have led to the emergence of reactive laser-synthesis techniques that exploit these methods’ character- istic, non-equilibrium conditions. Reactive laser-synthesis approaches foster unique chemical reactions that enable the formation of composite products like multimetallic nanoparticles, supported nanostructures, and complex …


Investigating Synthetic Methods For Tio2-Nayf4 Hybrid Nanocrystals, Nurul Muttakin Jan 2022

Investigating Synthetic Methods For Tio2-Nayf4 Hybrid Nanocrystals, Nurul Muttakin

Dissertations and Theses

The capacity to develop and expand the utility of a single nanostructure is one of the major issues in the field of hybrid nanocrystals. Major advancements in the fabrication of materials with multiple functionalities by combining many materials into a single nanoparticle entity are intriguing, but they still pose obstacles that must be addressed. This trend has been spurred by significant progressions in the wet-chemical synthesis of durable and easily programmable nanocrystals with various morphologies. The extent of the structural complexity of solution-based nanocrystals looks to be one of the inevitable avenues along which nanoscience will increasingly focus. We have …


Harmful Algal Blooms In Caesar Creek Lake And Their Relationship To Riparian Cover, Morgan C. Grunden Jan 2022

Harmful Algal Blooms In Caesar Creek Lake And Their Relationship To Riparian Cover, Morgan C. Grunden

Browse all Theses and Dissertations

Caesar Creek Lake (CCL) in Warren County, OH has recently been experiencing harmful algal blooms (HABs) which are most likely attributed to an excess of phosphorus (P) from fertilizers and manures applied to surrounding fields. Sediments act as a sink for P later supplying a source of P in lakes for HABs when waters become thermally stratified and anoxic. This study seeks to determine the relationship between HABs in CCL and riparian cover at the main tributaries, Anderson Fork and Caesar Creek. In order to do this, sediment samples were collected from four sample sites along Anderson Fork and three …


The Chemical Characterization Of Microplastic Polymer Composition From Various Littoral Environments On Cape Cod, Massachusetts, Leah Kosovsky Jan 2022

The Chemical Characterization Of Microplastic Polymer Composition From Various Littoral Environments On Cape Cod, Massachusetts, Leah Kosovsky

Chemistry Honors Papers

The increasing abundance of microplastic pollution in marine environments is a rising concern, and it has the potential to negatively affect the health and sustainability of marine organisms and ecosystems. Microplastics can harm organisms through a variety of chemical, biological, and physical mechanisms. The extent to which they are harmful varies greatly and is significantly dependent on the chemical and physical makeup of the plastic polymer. Due to this variability, it is important to characterize microplastic samples in various environments to better understand the risks associated with the debris in certain areas. Through field research, a spatial analysis of the …


Development Of Sensitive And Fast Immunoassay For Lyme Disease, Justin Cosgrove Jan 2022

Development Of Sensitive And Fast Immunoassay For Lyme Disease, Justin Cosgrove

Summer Scholarship, Creative Arts and Research Projects (SCARP)

Testing for Lyme disease has proven to be time consuming and inaccurate, especially in its early stages. The goal of this project is to develop a new diagnostic that has improved timeliness, sensitivity, and selectivity. This test is based on an enzyme-linked immunosorbent assay, or ELISA. To improve on what is currently in place, magnetic beads will be used. Unlike a normal ELISA, these magnetic beads are the binding site of the capture antibody instead of the microplate surface. With greatly increased surface area from the beads, the process can be much faster and detect far lesser concentrations of protein …