Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 3421 - 3450 of 33139

Full-Text Articles in Chemistry

Synthesis And Characterization Of Anderson-Evans Type Polyoxometalates, Antibacterial Properties, Hülya Avci Özbek Aug 2023

Synthesis And Characterization Of Anderson-Evans Type Polyoxometalates, Antibacterial Properties, Hülya Avci Özbek

Turkish Journal of Chemistry

In the present work, the new aluminium-substituted polyoxometalates of the Anderson-Evans type have been prepared and structurally defined by the reaction of aluminium (III) chloride hexahydrate and sodium tungstate dihydrate/sodium molybdate dihydrate in an aqueous basic medium. Elemental analysis, FT-IR, TGA, 1H NMR, and 31P NMR analysis revealed that these polyoxometalates had the following formula: [Ph4 P]3 [Al(OH)6 Mo6 O18]·4H2 O 1, [Ph4 P]3 [Al(OH)6 W6 O18]·4H2 O 2, [C7 H10N]3 [Al(OH)6 Mo6 O18]·4H2 O 3, [C7 H10N]3 [Al(OH)6 W6 O18]·4H2 O 4. The compounds 1 and 2 show promising antibacterial activity against gram-positive Staphylcoccus aureus ATCC 25923 and gram-negative …

Go to article

Preparation And Application Of Caffeic Acid Imprinted Polymer, Şeyda Karaman Ersoy, Esma Tütem, Kevser Sözgen Başkan, Mustafa Reşat Apak Aug 2023

Preparation And Application Of Caffeic Acid Imprinted Polymer, Şeyda Karaman Ersoy, Esma Tütem, Kevser Sözgen Başkan, Mustafa Reşat Apak

Turkish Journal of Chemistry

In the present study, molecularly imprinted polymers were synthesized using caffeic acid (CA) as a template molecule and then used for the extraction of CA and chlorogenic acid (CLA) from complex matrices. Syntheses were carried out in tetrahydrofuran as porogenic solvent using 4-vinyl pyridine, methacrylic acid, acrylamide, and 1-vinyl imidazole as monomers, ethylene glycol dimethacrylate as crosslinker and 2,2'-azobisisobutyronitrile as initiator. In polymerization processes, different ratios of the template:monomer:crosslinker (T:M:CrL) were used to obtain the most suitable polymer. Caffeic acid:4-vinylpiridine:ethylene glycol dimethacrylate's 1:4:16 mole ratio of MIP was determined as the most convenient polymer for CA recognition. In addition, nonimprinted …

Go to article

In Vitro Antioxidant Activity Of Alginate Nanoparticles Encapsulating The Aqueous Extract Of Coccinia Grandis L., Walimuni Nayomi Deshani De Silva, Anoja Priyadarshani Attanayake, Liyanage Dona Ashanti Menuka Arawwawala, Desiree Nedra Karunaratne, Geethi Kaushalya Pamunuwa Aug 2023

In Vitro Antioxidant Activity Of Alginate Nanoparticles Encapsulating The Aqueous Extract Of Coccinia Grandis L., Walimuni Nayomi Deshani De Silva, Anoja Priyadarshani Attanayake, Liyanage Dona Ashanti Menuka Arawwawala, Desiree Nedra Karunaratne, Geethi Kaushalya Pamunuwa

Turkish Journal of Chemistry

Bioactive compounds in medicinal plants are more susceptible to preventing oxidative stress. Encapsulation of herbal extracts has empowered the properties and characteristics of bioactive compounds. Nanoencapsulation allows the enhancement of the stability of extracts and targeted drug delivery. The present study aims to determine the antioxidant activity of alginate nanoparticles encapsulating the aqueous extract of Coccinia grandis L. (Family: Cucurbitaceae). The aqueous extract of C. grandis (AqCG) was prepared by using ultrasonication (40 ° C, 20 min, 40 kHz) followed by refluxing (2½ h). The prepared AqCG (1-5 mg/mL) encapsulated alginate nanoparticles were synthesized by ionic gelation with the addition …

Go to article

Phosphorus-Carrying Cascade Molecules: Inner Architecture To Biomedical Applications, Anbazhagan Thirumalai, Noureddine Elboughdiri, Karthick Harini, Koyeli Girigoswami, Agnishwar Girigoswami Aug 2023

Phosphorus-Carrying Cascade Molecules: Inner Architecture To Biomedical Applications, Anbazhagan Thirumalai, Noureddine Elboughdiri, Karthick Harini, Koyeli Girigoswami, Agnishwar Girigoswami

Turkish Journal of Chemistry

Cascade molecules are nearly uniform-sized macromolecules of small molecules or linear polymer cores built around symmetric branching units. A wide range of biological properties can be achieved with phosphorus-containing dendrimers, depending on their terminal functions, ranging from biomaterials to imaging, drug delivery, and acting as a drug by themselves. This feature article presents significant examples of phosphorus-containing dendrimers used to develop biochips, support cell cultures, carry or deliver biomacromolecules and drugs, bioimaging, and combinational benefits. Because of the thermal stability, ferrocene function, and physical and chemical properties of phosphorus, dendrimers show greater rigidity, mobility, and strength. These dendrimers will be …

Go to article

Theoretical Analysis Of Oled Performances Of Some Aromatic Nitrogen-Containing Ligands, Mustafa Eli̇k Aug 2023

Theoretical Analysis Of Oled Performances Of Some Aromatic Nitrogen-Containing Ligands, Mustafa Eli̇k

Turkish Journal of Chemistry

It is well-known that tris(8-hydroxyquinoline) aluminum (Alq3) complex and N,N'diphenyl-N,N'-bis(3-methylphenyl)-1,1'- diphenyl-4,4'-diamine compound (TPD) are widely used as electron transfer material (ETL) and hole transfer material (HTL) in organic light emitting diode (OLED) structure, respectively. Considering the reference materials, in the present work, the OLED performances of some cyclic aromatic structures such as 4,4'azopyridine [AZPY], 4,4'-bipyridine [BIPY], 1,2-bis[4'-(4-methylphenyl)2,2':6'2' '-terpyridin6-yl]ethyne (BISTERPY), 5,5'-diamino-2,2'-bipyridine (DABP), dipyrido[3,2-a:2',3'c]phenazine (DPP), 4,7-phenanthroline (PHEN) including nitrogen atom have been theoretically analyzed. It is important to note that B3LYP/6-31G(d) and B3LYP/TZP levels of the theory were taken into account for the calculations about monomeric and dimeric structures, respectively. Additionally, the …

Go to article

Acid-Base Potentiometric Titration Using A Stainless Steel Electrode Without Oxidative Treatment, Javier E. Vilasó-Cadre, Daniel Benítez-Fernández, Ilse A. López-Álvarez, F. Yuliana Tovar-Vázquez, María A. Arada-Pérez, Iván A. Reyes-Domínguez Aug 2023

Acid-Base Potentiometric Titration Using A Stainless Steel Electrode Without Oxidative Treatment, Javier E. Vilasó-Cadre, Daniel Benítez-Fernández, Ilse A. López-Álvarez, F. Yuliana Tovar-Vázquez, María A. Arada-Pérez, Iván A. Reyes-Domínguez

Turkish Journal of Chemistry

An AISI 304 stainless steel laminar electrode without oxidative treatment was investigated for the potentiometric titration of hydrochloric acid with sodium hydroxide. The proposed electrode was obtained from metalworking cuttings. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray fluorescence spectroscopy and X-ray diffraction were used to study the surface morphology and chemical composition of the electrode. The electrode showed a sensitivity of 59.18 ± 0.37 mV/pH, which was reproducible under intermediate conditions. Potentiometric titration showed a curve with deviations from pH 9.5 with respect to the glass electrode. However, this did not affect the quantification as the jumps of the …

Go to article

Waste Jean Derived Self N-Containing Activated Carbon As A Potential Electrode Material For Supercapacitors, Yavuz Gökçe Aug 2023

Waste Jean Derived Self N-Containing Activated Carbon As A Potential Electrode Material For Supercapacitors, Yavuz Gökçe

Turkish Journal of Chemistry

The rapid rise of the world population increases the annual amount of waste textile products. Textile products create a significant amount of CO2 , water, and chemical footprints during production. Therefore, the reusability of textile products has an important environmental and economic impact. Waste denim was used in this study to produce activated carbon (AC) samples as the alternative substance for supercapacitor electrodes. Characterisation studies showed that AC samples contain nitrogen originating from the elastane in the denim structure. Electrochemical characterisation tests proved the pseudocapacitive behaviour of the denim-derived AC due to the nitrogen content. Specific capacitance values observed for …

Go to article

Synthesizinge A Novel Zr2al-Gns Max Phase Ceramic With Superior Electrical Properties Using Pressureless Sintering Technique, Dumooa R. Hussein, Khalid K. Abbas, Ahmed M.H. Abdulkadhim Al-Ghaban Aug 2023

Synthesizinge A Novel Zr2al-Gns Max Phase Ceramic With Superior Electrical Properties Using Pressureless Sintering Technique, Dumooa R. Hussein, Khalid K. Abbas, Ahmed M.H. Abdulkadhim Al-Ghaban

Turkish Journal of Chemistry

A unique Zr2 Al-GNS MAX phase ceramic supported nanographene sheet was prepared using a cost-effective pressureless sintering technique under relatively low temperature. An experimental investigation was conducted to explore the lattice parameters using different temperatures, such as 1000, 1150, and 1300 °C. To characterize the crystal structure of the MAX phase ceramic, X-ray diffraction, field emission scanning electron microscopy imaging, energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HRTEM), and selected area diffraction (SAED) were utilized. The results revealed that the pressureless sintering technique was successfully utilized to synthesize the Zr2 Al-GNS MAX phase ceramic under 1150 °C with a …

Go to article

Effects Of Zsm-5 Zeolite On Pyrolysis Of Polystyrene: From Stabilizing To Catalyzing, Qing Yuan Ma, Zhen Huang, Xuan Ren, Jia Jia Zhao, Fu Chen, Li Jun Teng Aug 2023

Effects Of Zsm-5 Zeolite On Pyrolysis Of Polystyrene: From Stabilizing To Catalyzing, Qing Yuan Ma, Zhen Huang, Xuan Ren, Jia Jia Zhao, Fu Chen, Li Jun Teng

Turkish Journal of Chemistry

Nonisothermal pyrolysis measurements of polystyrene (PS)/ZSM-5 zeolite hybrids are conducted in N2 and thermogravimetric results have been kinetically analyzed with different isoconversional methods. Experimental results show that the addition of 5 and 10 wt.% ZSM-5 zeolite has increased the initial pyrolysis temperature of PS while the addition of 20 and 30 wt.% ZSM-5 zeolite can significantly decrease the initial pyrolysis temperature of PS. Elevated activation energy is resulted by adding low zeolite amount whereas reduced activation energy is obtained by adding high ZSM-5 amounts. The effect of zeolite ZSM-5 on PS pyrolysis can thus be observed to transfer from stabilizing …

Go to article

Polymer Architecture Effect On Rheology And Segmental Dynamics In Poly (Methyl Methacrylate)-Silica Nanocomposite Melts, Saeid Darvishi, Erkan Şenses Aug 2023

Polymer Architecture Effect On Rheology And Segmental Dynamics In Poly (Methyl Methacrylate)-Silica Nanocomposite Melts, Saeid Darvishi, Erkan Şenses

Turkish Journal of Chemistry

Architecturally different polymer chains lead to fundamentally different rheological responses and internal dynamics, which can be utilized to rationalize advanced thermoplastic nanocomposites with tunable mechanical behavior. In this work, three model poly (methyl methacrylate) (PMMA) polymers with linear, bottlebrush, and star architectures with the same total molar mass were investigated in their neat form, and nanocomposites with well-dispersed silica nanoparticles using rheology and broadband dielectric spectroscopy (BDS). The master curves of the dynamic moduli obtained by time-temperature superposition (TTS) over the entire range from the Rouse regime to the terminal flow and a sequence of significantly different relaxation modes were …

Go to article

Electronic Structures And Dielectric Function Of (5, 5) Cnt-C2h4o System: A First-Principles Study On The Detection Capability Of Cnt For Gas Sensing Applications, Alvanh Alem Pido, Art Anthony Munio Aug 2023

Electronic Structures And Dielectric Function Of (5, 5) Cnt-C2h4o System: A First-Principles Study On The Detection Capability Of Cnt For Gas Sensing Applications, Alvanh Alem Pido, Art Anthony Munio

Turkish Journal of Chemistry

Carbon nanotubes (CNTs) are known to have a wide range of applications in various fields of discipline. In this research, the ability of metallic armchair (5, 5) CNT to detect acetaldehyde (C2 H4 O) was investigated using first-principles density functional theory (DFT) as implemented in Quantum ESPRESSO with the Generalized Gradient Approximation (GGA). Accordingly, it was found that C2 H4 O preserved the metallic behavior of the CNT. However, some bands are found to have overlapped in both the valence and conduction regions of the electronic structures of the resulting system that are mainly caused by the p orbitals of …

Go to article

Hydrodynamic Voltammetry Of Fe2+/3+ In Aqueous Deep Eutectic Solvents Towards Redox Flow Batteries, Desiree Mae Prado, Xiaochen Shen, Robert Savinell, Clemens Burda Aug 2023

Hydrodynamic Voltammetry Of Fe2+/3+ In Aqueous Deep Eutectic Solvents Towards Redox Flow Batteries, Desiree Mae Prado, Xiaochen Shen, Robert Savinell, Clemens Burda

Faculty Scholarship

Deep eutectic solvents (DESs) have recently attracted much attention as potential green electrolyte solvents for redox flow batteries. DESs are considered not only as environmentally sustainable but also economically attractive electrolytes because they can be resourced from biological feedstock (alcohols, urea, choline) and are earth-abundant and of low toxicity. Despite these advantages, DESs still have limitations in important aspects such as reactant and ion transport, which is inhibited due to hydrogen-bonding-induced viscosity. Thus, improving the transport properties of redox species in DESs is essential. In addition, we explore the quantitative addition of water to ethaline (a 1:2 choline chloride: ethylene …

Go to article

Anharmonicity And Deuteration In The Ir Absorption And Emission Spectra Of Phenylacetylene, Vincent J. Esposito, Pierro Ferrari, Wybren Jan Buma, Christiaan Boersma, Cameron J. Mackie, Alessandra Candian, Ryan C. Fortenberry, Alexander G. G. M. Tielens Aug 2023

Anharmonicity And Deuteration In The Ir Absorption And Emission Spectra Of Phenylacetylene, Vincent J. Esposito, Pierro Ferrari, Wybren Jan Buma, Christiaan Boersma, Cameron J. Mackie, Alessandra Candian, Ryan C. Fortenberry, Alexander G. G. M. Tielens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Anharmonic cascade emission simulations, herein evinced by full reproduction and deep insights into recent emission spectroscopy experiments of phenylacetylene, are integral to the future successful analysis of JWST observational spectra. Experimental infrared absorption experiments conducted in this study reveal a complex spectrum dominated by quantum effects that are uncovered by anharmonic computational analysis. From this work, it becomes clear that phenylacetylene exhibits strong resonance coupling between fundamental and two-quanta combination modes as well as giving indication for coupling with higher-order, three-quanta combination bands. This study benchmarks the development of advanced computational methods that will be extended to larger systems of …

Go to article

Online Data Transmission Reduction Scheme For Energy Conservation In Wireless Video Sensor Networks, Iman Kadhum Abbood, Ali Kadhum Idrees Aug 2023

Online Data Transmission Reduction Scheme For Energy Conservation In Wireless Video Sensor Networks, Iman Kadhum Abbood, Ali Kadhum Idrees

Karbala International Journal of Modern Science

Wireless Video Sensor Networks (WVSNs) are networks of low-cost, low-power camera sensor nodes. These nodes communicate locally and process information to meet an application's goal. WVSNs are extensively used in diverse monitoring applications, such as security, military, industrial, medical, and environmental monitoring. However, the transmission of large amounts of data collected by video sensor nodes in WVSNs poses challenges in terms of energy consumption, bandwidth usage, and network congestion. Reducing energy for processing and transmitting data in WVSNs is difficult due to the huge amount of sensed data in real-time. To address this issue, this paper proposes an Online Data …

Go to article

Biogenesis Synthesis Of Zno Nps: Its Adsorption And Photocatalytic Activity For Removal Of Acid Black 210 Dye, Zahraa A. Najm, Mohammed A. Atiya, Ahmed K. Hassan Aug 2023

Biogenesis Synthesis Of Zno Nps: Its Adsorption And Photocatalytic Activity For Removal Of Acid Black 210 Dye, Zahraa A. Najm, Mohammed A. Atiya, Ahmed K. Hassan

Karbala International Journal of Modern Science

This study investigated the treatment of textile wastewater contaminated with Acid Black 210 dye (AB210) using zinc oxide nanoparticles (ZnO NPs) through adsorption and photocatalytic techniques. ZnO NPs were synthesized using a green synthesis process involving eucalyptus leaves as reducing and capping agents. The synthesized ZnO NPs were characterized using UV-Vis spectroscopy, SEM, EDAX, XRD, BET, Zeta potential, and FTIR techniques. The BET analysis revealed a specific surface area and total pore volume of 26.318 m2/g. SEM images confirmed the crystalline and spherical nature of the particles, with a particle size of 73.4 nm. A photoreactor was designed …

Go to article

Optimization Of Electrode Configurations For Calibration-Free, Remote Sensing Of Heavy Metals In Water Using Double-Potenital Step Anodic Coulometry, Jessica Bone Aug 2023

Optimization Of Electrode Configurations For Calibration-Free, Remote Sensing Of Heavy Metals In Water Using Double-Potenital Step Anodic Coulometry, Jessica Bone

Online Theses and Dissertations

Many areas around the world are known and predicted to suffer from arsenic-contaminated drinking water resulting in elevated medical issues. Current arsenic detection techniques require that a sample be taken at the site, carried to the lab, and then tested by a skilled technician, which is not practical for remote, hard to reach places. In collaboration with researchers at the University of Louisville and the University of Kentucky, we are designing an electrochemical cell for a calibration-free detection technique that can be performed remotely, eliminating the need for on-site technicians, and helping to prevent chronic arsenic poisoning. A validated and …

Go to article

Introducing High School Biology Students To Biochemistry With A Short, Content-Oriented Module, Archer Harrold, Allison Cruikshank, Bryan Penas, Rebecca Roston Aug 2023

Introducing High School Biology Students To Biochemistry With A Short, Content-Oriented Module, Archer Harrold, Allison Cruikshank, Bryan Penas, Rebecca Roston

Department of Chemistry: Faculty Publications

Many STEM disciplines are underrepresented to High School students. This is problematic as many students' decisions for college are shaped by their experiences and achievements in high school. Short content-oriented modules have been shown to encourage science identity and otherwise benefit the students' learning. Following the ASBMB's outreach protocol, we developed a short content-oriented module aimed at a high school biology classroom. Students interacted with 3D models of DNA and transcription factors while exploring structure–function relationships and introductory biochemistry topics. The high school teacher was impressed with the students' response to the module, specifically the ease with which students learned, …

Go to article

Ultrasound Assisted Comparative Study Of Fucolam And So-Dium Alginate And Impact On Their Physiochemical Proper-Ties Using Box-Behnken Design, Uday Bagale, Ammar Kadi, Artem Malinin, Varisha Anjum, Irina Potoroko Aug 2023

Ultrasound Assisted Comparative Study Of Fucolam And So-Dium Alginate And Impact On Their Physiochemical Proper-Ties Using Box-Behnken Design, Uday Bagale, Ammar Kadi, Artem Malinin, Varisha Anjum, Irina Potoroko

Karbala International Journal of Modern Science

The article discusses about the possibility of comparing the impact of ultrasonic treatment on fucolam and sodium algi-nate. The purpose was to study the effect of micronization on the sulfated heteropolysaccharide fucolam, analyzing its dispersed state and accessibility by reducing its molecular weight and increasing antioxidant activity. The optimization of the micronization process was carried out using the Box-Behnken Design (BBD) method, with a sonication time ranging from 15 to 45 min, power ranging from 50 to 100 W/cm2, and temperature between 30 °C and 40 °C. The fixed lower fucolam concentration was 0.1%. The results illustrated that sonochemical treatment …

Go to article

Deep Learning-Based Cad System For Predicting The Covid-19 X-Ray Images, Aqeel R. Talib, Hana’ M. Ali Aug 2023

Deep Learning-Based Cad System For Predicting The Covid-19 X-Ray Images, Aqeel R. Talib, Hana’ M. Ali

Karbala International Journal of Modern Science

According to World Health Organization data, Coronavirus (COVID-19) has infected about 660, 378, 145 patients around the world. It is nonetheless difficult for physicians to detect COVID-19 infections out of CT or X-ray radiographs. Thus, several computer-aided diagnosis (CAD) systems based on deep learning and radiographs were developed to detect COVID-19 infections. However, the majority of approaches considered small datasets, which is ineligible to provide diverse COVID-19 radiographs. This work utilizes a massive number of X-ray radiographs, and compared standard CNN, DenseNet-121, and GoogLeNet for isolating COVID-19 infections out from normal and other pneumonia radiographs. The dataset in this work …

Go to article

Additive Effects Of Cyclic Peptide [R4w4] When Added Alongside Azithromycin And Rifampicin Against Mycobacterium Avium Infection, Melissa Kelley, Kayvan Sasaninia, Arbi Abnousian, Ali Badaoui, James Owens, Abrianna Beever, Nala Kachour, Rakesh Kumar Tiwari, Vishwanath Venketaraman Aug 2023

Additive Effects Of Cyclic Peptide [R4w4] When Added Alongside Azithromycin And Rifampicin Against Mycobacterium Avium Infection, Melissa Kelley, Kayvan Sasaninia, Arbi Abnousian, Ali Badaoui, James Owens, Abrianna Beever, Nala Kachour, Rakesh Kumar Tiwari, Vishwanath Venketaraman

Pharmacy Faculty Articles and Research

Mycobacterium avium (M. avium), a type of nontuberculous mycobacteria (NTM), poses a risk for pulmonary infections and disseminated infections in immunocompromised individuals. Conventional treatment consists of a 12-month regimen of the first-line antibiotics rifampicin and azithromycin. However, the treatment duration and low antibiotic tolerability present challenges in the treatment of M. avium infection. Furthermore, the emergence of multidrug-resistant mycobacterium strains prompts a need for novel treatments against M. avium infection. This study aims to test the efficacy of a novel antimicrobial peptide, cyclic [R4W4], alongside the first-line antibiotics azithromycin and rifampicin in reducing M. avium survival. Colony-forming unit (CFU) …

Go to article

The Synthesis And Optimization Of Conductive Carbons From Renewable Resources For Supercapacitor Applications, Iris Denmark Aug 2023

The Synthesis And Optimization Of Conductive Carbons From Renewable Resources For Supercapacitor Applications, Iris Denmark

Theses and Dissertations

The use of fossil fuels has played a pivotal role in the evolution of energy storage devices and the generation of electricity. With that, we have now entered an era in which we have become primarily dependent on these non-renewable resources which have become increasingly scarce overtime. This has driven us toward a pertinent demand for alternative sources of energy. There are various forms of alternative energy in which biomass is the most used. Carbon is becoming the most commonly used material for energy applications due to its versatility and bioavailability, including that which is sourced from biomass. Herein is …

Go to article

Ruthenium Olefin Metathesis Catalysts Featuring Chelating Benzylidene-Triazole Ligands, Allegra L. Liberman-Martin Aug 2023

Ruthenium Olefin Metathesis Catalysts Featuring Chelating Benzylidene-Triazole Ligands, Allegra L. Liberman-Martin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this issue of Chem Catalysis, Shi and co-workers describe the synthesis and olefin metathesis activity of ruthenium complexes with chelating benzylidene-triazole ligands. Catalyst decomposition is slow at up to 80°C, which enables challenging catalytic reactions, including cross-metathesis of trans-alkenes and macrocycle synthesis by dynamic covalent chemistry.

Go to article

Mechanochemical Esterification Of Cellulose Nanofibers Lyophilized From Eutectic Water–Tert-Butanol Mixtures, Miran Mavlan, Taehoo Chang, Rudan Feng, Jake R. Wilkinson, Robert J. Nicholas, Nosa B. Idahagbon, Jeffrey Youngblood, Alexander Wei Aug 2023

Mechanochemical Esterification Of Cellulose Nanofibers Lyophilized From Eutectic Water–Tert-Butanol Mixtures, Miran Mavlan, Taehoo Chang, Rudan Feng, Jake R. Wilkinson, Robert J. Nicholas, Nosa B. Idahagbon, Jeffrey Youngblood, Alexander Wei

Department of Chemistry Faculty Publications

Freeze-dried CNFs can be modified by mechanochemical (MC) processes with minimal use of auxiliary solvents, however aggregation of nanofibers during lyophilization compromises their granularity and reaction efficiency. Adding 10 wt% tert-butanol (TBA) to aqueous slurries of wood-derived CNF creates a eutectic mixture that reduces hornification during lyophilization, resulting in well-formed aerogels with minimal shrinkage in volume. CNFs lyophilized from mixtures containing at least 10 wt% TBA exhibit an order of magnitude increase in specific surface area relative to CNFs freeze-dried from water alone. The amount of TBA and input energy needed for lyophilization can be reduced considerably by dewatering …

Go to article

Changes In An Enzyme Ensemble During Catalysis Observed By High Resolution Xfel Crystallography, Nathan J. Smith, Medhanjali Dasgupta, David C. Wych, Cole Dolamore, Raymond G. Sierra, Stella Lisova, Darya Marchany-Rivera, Aina E. Cohen, Sébastien Boutet, Mark S. Hunter, Christopher Kupitz, Frédéric Poitevin, Frank R. Moss Iii, Aaron S. Brewster, Nicholas K. Sauter, Iris D. Young, Alexander M. Wolff, Virendra K. Tiwari, Nivesh Kumar, David B. Berkowitz, Ryan G. Hadt, Michael C. Thompson, Alec H. Follmer, Mark A. Wilson Aug 2023

Changes In An Enzyme Ensemble During Catalysis Observed By High Resolution Xfel Crystallography, Nathan J. Smith, Medhanjali Dasgupta, David C. Wych, Cole Dolamore, Raymond G. Sierra, Stella Lisova, Darya Marchany-Rivera, Aina E. Cohen, Sébastien Boutet, Mark S. Hunter, Christopher Kupitz, Frédéric Poitevin, Frank R. Moss Iii, Aaron S. Brewster, Nicholas K. Sauter, Iris D. Young, Alexander M. Wolff, Virendra K. Tiwari, Nivesh Kumar, David B. Berkowitz, Ryan G. Hadt, Michael C. Thompson, Alec H. Follmer, Mark A. Wilson

Department of Chemistry: Faculty Publications

Enzymes populate ensembles of structures with intrinsically different catalytic proficiencies that are difficult to experimentally characterize. We use time-resolved mix-and-inject serial crystallography (MISC) at an X-ray free electron laser (XFEL) to observe catalysis in a designed mutant (G150T) isocyanide hydratase (ICH) enzyme that enhances sampling of important minor conformations. The active site exists in a mixture of conformations and formation of the thioimidate catalytic intermediate selects for catalytically competent substates. A prior proposal for active site cysteine charge-coupled conformational changes in ICH is validated by determining structures of the enzyme over a range of pH values. A combination of large …

Go to article

Change Is The Only Constant: A Virtual Issue On Contemporary Catalysis, Shelley Minteer, Stephanie L. Brock, Géraldine Masson, Raymond E. Schaak Aug 2023

Change Is The Only Constant: A Virtual Issue On Contemporary Catalysis, Shelley Minteer, Stephanie L. Brock, Géraldine Masson, Raymond E. Schaak

Chemistry Faculty Research & Creative Works

No abstract provided.

Go to article

Unraveling Hydrogen Atom Transfer Mechanisms With Voltammetry: Oxidative Formation And Reactivity Of Cobalt Hydride, Dylan G. Boucher, Andrew D. Pendergast, Xiangyu Wu, Zachary A. Nguyen, Rohit G. Jadhav, Song Lin, Henry S. White, Shelley D. Minteer Aug 2023

Unraveling Hydrogen Atom Transfer Mechanisms With Voltammetry: Oxidative Formation And Reactivity Of Cobalt Hydride, Dylan G. Boucher, Andrew D. Pendergast, Xiangyu Wu, Zachary A. Nguyen, Rohit G. Jadhav, Song Lin, Henry S. White, Shelley D. Minteer

Chemistry Faculty Research & Creative Works

The utility of transition metal hydride catalyzed hydrogen atom transfer (MHAT) has been widely demonstrated in organic transformations such as alkene isomerization and hydro functionalization reactions. However, the highly reactive nature of the hydride and radical intermediates has hindered mechanistic insight into this pivotal reaction. Recent advances in electrochemical MHAT have opened up the possibility for new analytical approaches for mechanistic diagnosis. Here, we report a voltametric interrogation of Co-Based MHAT reactivity, describing in detail the oxidative formation and reactivity of the key Co-H intermediate and its reaction with aryl alkenes. Insights from cyclic voltammetry and finite element simulations help …

Go to article

Rural Science Teachers Social Network Analysis Matrices, Rebecca L. Sansom, Tracy Poulsen Aug 2023

Rural Science Teachers Social Network Analysis Matrices, Rebecca L. Sansom, Tracy Poulsen

ScholarsArchive Data

These are the social network matrices for our study of rural science teachers. Each matrix is located on a separate tab on the spreadsheet.

Go to article

Synthesis And Characterization Of The N-Succinyl-L,L-Diaminopimelic Acid Desuccinylase (Dape) Alternate Substrate Analog N,N-Dimethyl-L,L-Sdap, Zachary J. Liveris, Emma H. Kelley, Emma Simmons, Katherine Konczak, Marlon Lutz Jr., Miguel Ballicora, Ken W. Olsen, Daniel P. Becker Ph.D. Aug 2023

Synthesis And Characterization Of The N-Succinyl-L,L-Diaminopimelic Acid Desuccinylase (Dape) Alternate Substrate Analog N,N-Dimethyl-L,L-Sdap, Zachary J. Liveris, Emma H. Kelley, Emma Simmons, Katherine Konczak, Marlon Lutz Jr., Miguel Ballicora, Ken W. Olsen, Daniel P. Becker Ph.D.

Chemistry: Faculty Publications and Other Works

Growing antibiotic resistance by pathogenic bacteria has led to a global crisis. The bacterial enzyme N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) provides a very attractive target for the discovery of a new class of antibiotics, as it resides exclusively in many pathogenic bacterial strains and is a key enzyme in the lysine biosynthetic pathway. This pathway is responsible for the production of lysine as well as meso-diaminopimelate (m-DAP), both of which are required for peptidoglycan cell-wall synthesis, and lysine for peptide synthesis. The enzyme DapE catalyzes the hydrolysis of N-succinyl-l,l-diaminopimelic acid (l,l-SDAP) to succinate and l,l-diaminopimelic …

Go to article

Self-Immolative Hydrogels With Stimulus-Mediated On-Off Degradation., Jue Gong, Aneta Borecki, Elizabeth R Gillies Aug 2023

Self-Immolative Hydrogels With Stimulus-Mediated On-Off Degradation., Jue Gong, Aneta Borecki, Elizabeth R Gillies

Chemistry Publications

Hydrogels are of interest for a wide range of applications from sensors to drug delivery and tissue engineering. Self-immolative polymers, which depolymerize from end-to-end following a single backbone or end-cap cleavage, offer advantages such as amplification of the stimulus-mediated cleavage event through a cascade degradation process. It is also possible to change the active stimulus by changing only a single end-cap or linker unit. However, there are very few examples of self-immolative polymer hydrogels, and the reported examples exhibited relatively poor stability in their nontriggered state or slow degradation after triggering. Described here is the preparation of hydrogels composed of …

Go to article

Enhancing The Performance Of Microbial Fuel Cells Via Metabolic Engineering Of Escherichia Coli For Phenazine Production, Olja Simoska, Dale A. Cummings, Erin M. Gaffney, Claire Langue, Tommy G. Primo, Courtney J. Weber, Corbin E. Witt, Shelley D. Minteer Aug 2023

Enhancing The Performance Of Microbial Fuel Cells Via Metabolic Engineering Of Escherichia Coli For Phenazine Production, Olja Simoska, Dale A. Cummings, Erin M. Gaffney, Claire Langue, Tommy G. Primo, Courtney J. Weber, Corbin E. Witt, Shelley D. Minteer

Chemistry Faculty Research & Creative Works

One of the central roles in the design, development, and application advances in mediator-Based microbial electrochemical systems, such as microbial fuel cells (MFCs), is the establishment of efficient and successful communication between conductive electrode surfaces and microorganisms via modes of extracellular electron transfer (EET). Most microbial-Based systems require the use of artificial electroactive mediators in order to facilitate and/or enhance electron transfer. Our previous work established an exogenous phenazine-Based library as a mediator system to enable EET from the model microorganism Escherichia coli as a promising biotechnological host. However, the addition of exogenous mediators to a microbial electrochemical system has …

Go to article

First Prev Next Last