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2024

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Articles 31 - 60 of 1341

Full-Text Articles in Chemistry

Peptides And Metalloproteins: Evolution, Catalysis And Material Design, Dona Imanga Upamadi Edirisinghe Dec 2024

Peptides And Metalloproteins: Evolution, Catalysis And Material Design, Dona Imanga Upamadi Edirisinghe

Dissertations - ALL

Peptide hydrogels are an important class of biomaterials that have gained significant attention in recent years. The stimuli responsive materials change their properties in response to pH, redox, temperature and enzymes and this property allowed us to design the materials with tunable properties based on their end application. This dissertation reports the de novo design, synthesis and characterization of short chain peptide sequences and optimizations of those in order to develop them into potential candidates in wound care and drug delivery applications. The investigation of these novel peptide sequences will open up new possibilities to tailor the properties through simple …


Synthesis, Characterization, And Investigation Of Photochemical And In Vitro Properties Of Novel Zn(Ii) Phthalocyanine, Yasemi̇n Bayğu Yildiz, Ni̇lgün Kabay, Burak Yildiz, İpek Ömeroğlu, Mahmut Durmuş, E. Riza Karagür, Hakan Akça, Çağri Ergi̇n, Yaşar Gök Dec 2024

Synthesis, Characterization, And Investigation Of Photochemical And In Vitro Properties Of Novel Zn(Ii) Phthalocyanine, Yasemi̇n Bayğu Yildiz, Ni̇lgün Kabay, Burak Yildiz, İpek Ömeroğlu, Mahmut Durmuş, E. Riza Karagür, Hakan Akça, Çağri Ergi̇n, Yaşar Gök

Turkish Journal of Chemistry

In our work, a new non-peripheral zinc(II) phthalocyanine bearing octa carboxylic acid ethyl ester derivative substituted triazole attached propylmercaptothiobenzylmercapto derivative was synthesized by the tetramerization reaction of phthalonitrile. The photochemical in vitro photodynamic activity of zinc(II) phthalocyanine (ZnPc-I), such as human non-small cell lung carcinoma cell lines, was investigated in this study. The singlet oxygen generation property of novel zinc(II) phthalocyanine (ZnPc-I) was also examined due to the significantly high singlet oxygen quantum yield of ZnPc-I (ΦΔ = 0.66). The antiproliferative effects of ZnPc-I were also investigated on A549 and H1299 cell lines, our results demonstrate that the ZnPc-I has …


A Fast And Responsive Turn-On Fluorescent Probe Based On A Quinone Conjugated Alkoxy Derivative For Biothiols And A Cellular Imaging Study, Ulviyye Nemetova, Ayşe Nur Önem, Alev Er, Sefa Çeli̇k, Ayşen E. Özel, Sevi̇m Akyüz, Mustafa Özyürek, Si̇bel Şahi̇nler Ayla Dec 2024

A Fast And Responsive Turn-On Fluorescent Probe Based On A Quinone Conjugated Alkoxy Derivative For Biothiols And A Cellular Imaging Study, Ulviyye Nemetova, Ayşe Nur Önem, Alev Er, Sefa Çeli̇k, Ayşen E. Özel, Sevi̇m Akyüz, Mustafa Özyürek, Si̇bel Şahi̇nler Ayla

Turkish Journal of Chemistry

Detection of intracellular biothiols (cysteine (CYS), N-acetyl cysteine (NAC) and glutathione (GSH)) with high-selectivity and sensitivity is important to reveal biological functions. In this study, 2-(2-methoxy-4-methylphenoxy)-3-chloro-5,8-dihydroxynaphthalene-1,4-dione (3) (DDN-O) compound was newly synthesized and used as a fluorogenic probe (detector molecule) in the fluorometric method for the rapid, highly selective and sensitive determination of biothiols. The intensity values (λex = 260 nm, λem = 620 nm) of the product were measured by adding biotihols to the reaction medium at varying concentrations and the glutathione equivalent thiol content (GETC) values of each biotiol were calculated. Using the compoud (3), the reference biotiol …


Understanding Ammonia's Role In Mitigating Concentration Polarization In Anion-Exchange Membrane Electrodialysis, Abdallah Timmaoui, Mahmoud Ferhat, Nesri̇ne Souad Ferhat, Ahmed Hamdi Dec 2024

Understanding Ammonia's Role In Mitigating Concentration Polarization In Anion-Exchange Membrane Electrodialysis, Abdallah Timmaoui, Mahmoud Ferhat, Nesri̇ne Souad Ferhat, Ahmed Hamdi

Turkish Journal of Chemistry

In processes such as electrodialysis, the applied electrical potential is constrained by concentration polarization at the membrane/solution interface. This polarization, which intensifies at higher current densities, impedes ion transport efficiency and may lead to problems such as salt precipitation, membrane degradation, and increased energy consumption. Therefore, understanding concentration polarization is essential for enhancing membrane performance, improving efficiency, and reducing operational costs. This study investigates the impact of ammonia buffer (NH₄⁺/NH₃) on sulfate ion transport through anion-exchange membranes, with a particular focus on limiting current density and concentration polarization under constant current conditions. Our findings demonstrate that ammonia effectively eliminates concentration …


New Naphthalene-Linked Pyrazoline-Thiazole Hybrids As Prominent Antilung And Antibreast Cancer Inhibitors, Hali̇li̇brahi̇m Çi̇ftçi̇, Masami Otsuka, Mikako Fujita, Belgi̇n Sever Dec 2024

New Naphthalene-Linked Pyrazoline-Thiazole Hybrids As Prominent Antilung And Antibreast Cancer Inhibitors, Hali̇li̇brahi̇m Çi̇ftçi̇, Masami Otsuka, Mikako Fujita, Belgi̇n Sever

Turkish Journal of Chemistry

Epidermal growth factor receptor (EGFR) and HER2, pioneer members of the receptor tyrosine kinase subfamily, are frequently mutated and/or overexpressed in several types of human cancers, including non-small cell lung cancer (NSCLC) and breast cancer, which are leading causes of cancer-related deaths worldwide. EGFR and HER2-focused anti-NSCLC and anti-breast cancer studies encouraged us to search for new potential agents. For this purpose, in the current work, naphthalene-linked pyrazoline-thiazole hybrids (BTT1-10 and BTP1-10) were synthesized and examined for their antiproliferative effects on A549 NSCLC and MCF-7 breast cancer cell lines. According to the results, MTT assay showed that BTT-5 induced strong …


Analysis And Optimization Of The Adsorption Of Lead Ions On A New Material Based On Silica Synthesized From Blast Furnace Slag, Toufik Chouchane, Ouahida Khireddine, Sabiha Chouchane, Mohamed Tayeb Abedghars, Hazem Meradi Dec 2024

Analysis And Optimization Of The Adsorption Of Lead Ions On A New Material Based On Silica Synthesized From Blast Furnace Slag, Toufik Chouchane, Ouahida Khireddine, Sabiha Chouchane, Mohamed Tayeb Abedghars, Hazem Meradi

Turkish Journal of Chemistry

A novel silica-based material (SBM), synthesized from chemically, thermally, and mechanically treated blast furnace slag (TBFS), was examined for its batch-mode lead adsorption capacity, based on various parameters. Physico-chemical examinations revealed that the formulation of the new material (SBM) consists mainly of silica, which represents 81.79% of its total composition. After modification, the measured specific surface area changed significantly, from 275.8 to 480.13 m2/g, with a point of zero charge (PZC) of approximately 3.4 on the pH scale. The experiment revealed that the driving factors (contact time, stirring speed, solution pH, temperature, and initial concentration) greatly influenced the improvement of …


Preparation Of Manganese-Doped Carbon Quantum Dots@Halloysite Nanotubes Composites Films For Advanced Uv Shielding Properties, Xiao Zhang, Bin Wang Dec 2024

Preparation Of Manganese-Doped Carbon Quantum Dots@Halloysite Nanotubes Composites Films For Advanced Uv Shielding Properties, Xiao Zhang, Bin Wang

Turkish Journal of Chemistry

The development of Ultraviolet (UV) shielding materials are of great importance to protect human's health concerns and prevent the degradation of organic matters. However, the synthesis of highly efficient UV shielding polymer nanocomposites is currently limited by the agglomeration of inorganic anti-UV nanoparticles (NPs) within the polymer matrix and limited absorption spectrum of UV shielding agents. In this study, highly effective manganese doped carbon quantum dots@halloysite nanotubes composites (Mn-CDs@HNTs/PAS) were successfully synthesized by loading manganese doped carbon quantum dot (Mn-CDs) into UV shielding effective halloysite nanotubes (HNTs) via solvothermal method, followed by polymerization modification. The results show that inorganic NPs …


Synthesis, Structure, Hirshfeld Surface Analysis, And Molecular Docking Studies Of The Cocrystal Between The Cu(Ii) Complex Of Salicylic Acid And Uncoordinated Piracetam, Nazokat N. Yuldasheva, Ikram I. Abdullaev, Oybek I. Khudoyberganov, Lola A. Gandjaeva, Pirnazar K. Kodamboev, Elyor Sh. Samandarov, Adkhamjon S. Normamatov, Abror Kh. Ruzmetov, Yuldosh Y. Yakubov, C. Balakrishnan, Bakhtiyar T. Ibragimov, Aziz Bakhti̇yarovich Ibragimov Dec 2024

Synthesis, Structure, Hirshfeld Surface Analysis, And Molecular Docking Studies Of The Cocrystal Between The Cu(Ii) Complex Of Salicylic Acid And Uncoordinated Piracetam, Nazokat N. Yuldasheva, Ikram I. Abdullaev, Oybek I. Khudoyberganov, Lola A. Gandjaeva, Pirnazar K. Kodamboev, Elyor Sh. Samandarov, Adkhamjon S. Normamatov, Abror Kh. Ruzmetov, Yuldosh Y. Yakubov, C. Balakrishnan, Bakhtiyar T. Ibragimov, Aziz Bakhti̇yarovich Ibragimov

Turkish Journal of Chemistry

The cocrystal or supramolecular complex between Cu(II) complex of salicylic acid and uncoordinated piracetam has been synthesized. Its structure is characterized by element analysis, FT-IR, UV-Visible spectroscopy and X-ray crystallography. Spectroscopic methods confirm the formation of the metal complex while X-ray crystallography establishes molecular and crystal structure of the obtained compound. Binuclear Cu(II) complex of salicylic acid (complex molecule) is in the form of “Chinese lantern” and it interacts with uncoordinated piracetam by complicated system of H-bonds. However, according to the Hirshfeld surface analysis a contribution of the O•••H/H•••O contacts is only 24.9% while H•••H and H•••C/C•••H contacts account for …


Capacity-Weighted Figures-Of-Merit For Battery Transport Metrics, Cj Sturgill, Christopher Sutton, Julian Schwenzel, Morgan Stefik Dec 2024

Capacity-Weighted Figures-Of-Merit For Battery Transport Metrics, Cj Sturgill, Christopher Sutton, Julian Schwenzel, Morgan Stefik

Faculty Publications

New battery materials with improved transport are needed. Typical measurements yield widely varying voltage-dependent diffusivities and reporting practices are diverse. Some materials (e.g. first-order phase change) have most redox occur at a specific voltage and may be sufficiently represented by singular transport metrics. Many rapid intercalation materials, however, exhibit second-order phase transitions with redox over a broad voltage range. How should such cases be compared? The use of capacity-weighted average values is suggested where voltage-dependent metrics are consolidated into representative descriptors as figures-of-merit. Examples are elaborated where differential capacity (dQ/dV) is used to derive a …


Synthesis Of Higher-Order Catenanes And Catenane-Based Materials, Gray Harlan Dec 2024

Synthesis Of Higher-Order Catenanes And Catenane-Based Materials, Gray Harlan

Arts & Sciences Graduate Student Theses and Dissertations

Catenanes are a subset of mechanically interlocked molecules (MIMs) and are composed of interlocked rings that can be oriented linearly, radially, or branched. A defining feature of all MIMs is that they are bound through their architectures consisting of mechanical bonds, leading to unique topologies. Catenanes have attracted interest due to their stimuli-responsive behavior and the degrees of freedom afforded by the mechanical bond, a feature which is absent with standard covalent bonds. The stimuli responsiveness of catenanes arises from their templated syntheses, where two or more pre-macrocycles are brought together by a driving force. Various templation strategies rely on …


Brain Endothelial Permeability, Transport, And Flow Assessed Over 10 Orders Of Magnitude Using The In Situ Brain Perfusion Technique, Quentin R. Smith, Haritha Mandula, Jagan Mohan R. Parepally, Jun Oki, Fancy Thomas, Helen R. Thorsheim, Abraham J. Al‑Ahmad, Thomas J. Abbruscato, Per Ask, David S. Hage, Peter J. Robinson Dec 2024

Brain Endothelial Permeability, Transport, And Flow Assessed Over 10 Orders Of Magnitude Using The In Situ Brain Perfusion Technique, Quentin R. Smith, Haritha Mandula, Jagan Mohan R. Parepally, Jun Oki, Fancy Thomas, Helen R. Thorsheim, Abraham J. Al‑Ahmad, Thomas J. Abbruscato, Per Ask, David S. Hage, Peter J. Robinson

David Hage Publications

Background Cerebral blood flow normally places a limit on the magnitude of brain vascular permeability (P) that can be measured in vivo. At normal cerebral blood flow, this limit falls at the lower end of lipophilicity for most FDAapproved CNS drugs. In this study, we report on two methods that can be used to overcome this limitation and measure brain vascular permeability values that are up to ~1000 times higher using the in situ brain perfusion technique.

Methods Rat brain was perfused with physiological saline at increased flow rate and in the presence of various concentrations of plasma protein, serum …


Analysis Of Dense Metals Accumulation In Shikaripara Stone Mines, Gopinath Gorai, Nirajan Kumar Mandal Dec 2024

Analysis Of Dense Metals Accumulation In Shikaripara Stone Mines, Gopinath Gorai, Nirajan Kumar Mandal

Makara Journal of Science

This study aimed to measure the amount of dangerous substances in the cultivated area of the Shikaripara stone mines in Jharkhand, India, which are well known for their stone quarrying. Sixteen soil samples were collected at varying dis-tances from the Shikaripara stone mines in the Dumka District of Jharkhand. The metals found in these samples in-clude Pb, As, Zn, Mn, Cd, Cu, Fg, and Fe. The combined amount of the elements was calculated by inductively coupled plasma mass spectrometry. Enrichment factor, accumulation index, contamination factor, pollution load index (PLI), Nemerow index, and ecological risk index (RI) were employed to assess …


Vibrational And Electronic Spectroscopy Of 2-Cyanoindene Cations, Thomas E. Douglas-Walker, Eleanor K. Ashworth, Mark H. Stockett, Francis C. Daly, Isabelle Chambrier, Vincent J. Esposito, Marius Gerlach, Angel Zheng, Julianna Palotás, Andrew N. Cammidge, Ewen K. Campbell, Sandra BrüNken, James N. Bull Dec 2024

Vibrational And Electronic Spectroscopy Of 2-Cyanoindene Cations, Thomas E. Douglas-Walker, Eleanor K. Ashworth, Mark H. Stockett, Francis C. Daly, Isabelle Chambrier, Vincent J. Esposito, Marius Gerlach, Angel Zheng, Julianna Palotás, Andrew N. Cammidge, Ewen K. Campbell, Sandra BrüNken, James N. Bull

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

2-Cyanoindene is one of the few specific aromatic or polycyclic aromatic hydrocarbon (PAH) molecules positively identified in Taurus molecular cloud-1 (TMC-1), a cold, dense molecular cloud that is considered the nearest star-forming region to Earth. We report cryogenic mid-infrared (550–3200 cm–1) and visible (16,500–20,000 cm–1, over the D2 ← D0 electronic transition) spectra of 2-cyanoindene radical cations (2CNI+), measured using messenger tagging (He and Ne) photodissociation spectroscopy. The infrared spectra reveal the prominence of anharmonic couplings, particularly over the fingerprint region. There is a strong CN-stretching mode at 2177 ± 1 cm–1 (4.593 …


Utility Of Immobilized Metal Salens As Electrocatalysts: Fuel Cells And Organic Electrosynthesis, Zachary A. Nguyen, Shelley D. Minteer Dec 2024

Utility Of Immobilized Metal Salens As Electrocatalysts: Fuel Cells And Organic Electrosynthesis, Zachary A. Nguyen, Shelley D. Minteer

Chemistry Faculty Research & Creative Works

There have been significant advancements in the electrosynthesis of fuels and organic molecules, making it an increasingly sustainable and cost-effective alternative to traditional chemical redox reagents. Early versions of these systems faced challenges in chemo selectivity due to high applied overpotentials, which have been mitigated with the introduction of molecular electrocatalysts, like metal salens (MSalens). These MSalens reduce the required overpotentials, increase turnover numbers (TON), and have simple modularity within their ligand structure allowing for tunable selectivity. While these MSalen electrocatalysts are typically used homogeneously for engineering simplicity, downstream separations are often costly and time-consuming. Immobilization of MSalens addresses these …


Organic Alkalinity Distributions, Characteristics, And Application To Carbonate System Calculations In Estuarine And Coastal Systems, Christopher W. Hunt, Joseph Salisbury, Xuewu Liu, Robert H. Byrne Dec 2024

Organic Alkalinity Distributions, Characteristics, And Application To Carbonate System Calculations In Estuarine And Coastal Systems, Christopher W. Hunt, Joseph Salisbury, Xuewu Liu, Robert H. Byrne

Faculty Publications

The capacity of aquatic systems to buffer acidification depends on the sum contributions of various chemical species to total alkalinity (TA). Major TA contributors are inorganic, with carbonate and bicarbonate considered the most important. However, growing evidence shows that many rivers, estuaries, and coastal waters contain dissolved organic molecules with charge sites that create organic alkalinity (OrgAlk). This study describes the first comparison of (1) OrgAlk distributions and (2) acid–base properties in contrasting estuary-plume systems: the Pleasant (Maine, USA) and the St. John (New Brunswick, CA). The substantial concentrations of OrgAlk in each estuary were sometimes not conservative with salinity …


An Energy Resource Management For Cluster Based Iohv Supported By Fog Computing, Ahmed Jawad Kadhim Dec 2024

An Energy Resource Management For Cluster Based Iohv Supported By Fog Computing, Ahmed Jawad Kadhim

Karbala International Journal of Modern Science

Internet of Hybrid Vehicle Networks (IoHV) is a network generated by merging the Internet with a Hybrid Vehicular Ad-Hoc Network (H-VANET). In IoHV, various types of electric and fuel vehicles create tasks. However, executing several tasks by electric vehicles affects their lifetime because they suffer from energy limitation issues which is one of the IoHV challenges. On the other hand, fuel vehicles and fog nodes have unlimited energy and can be used to execute most tasks of electric vehicles quickly. In this paper, we produce a new Energy Resource management Technique for IoHV called ERTH that aims to offload the …


Engineering Functionalized Nanomaterials For Targeting And Ablating Biofilms On Surfaces, Dhanush Lakmal Yapa Amarasekara Dec 2024

Engineering Functionalized Nanomaterials For Targeting And Ablating Biofilms On Surfaces, Dhanush Lakmal Yapa Amarasekara

Theses and Dissertations

Biofilms on both the surface and interior of medical devices pose major challenges, including hindering device performance and serving as infection sources. These biofilms form a protective layer around bacteria, shielding them from the body’s immune system and antibiotics. This makes infections difficult to treat, as the bacteria within the biofilm are resistant to both antibiotics and immune defenses. Additionally, biofilms can induce inflammation and irritation in nearby tissues, leading to further health complications. Antibiotic resistance raises concerns about the emergence of multi-drug resistant (MDR) pathogens. MDR infections are difficult to treat, leading to prolonged hospital stays and the need …


Biothermodynamics Of Metal And Dna Coordination To The Pneumococcal Transcription Factors Adcr, Scza, And Copr, Alexander James Cutright Dec 2024

Biothermodynamics Of Metal And Dna Coordination To The Pneumococcal Transcription Factors Adcr, Scza, And Copr, Alexander James Cutright

Theses and Dissertations

ransition metals are micronutrients that play critical roles in all forms of life, acting as stabilizing ions, catalytic centers, and as signaling ions. Due to their importance, classes of biomolecules have been designed with the sole purpose of regulating their intracellular concentrations. One group of which are transcription factors, which regulate intracellular metal concentration by activating or repressing transcription, dependent on metal availability. The activation of transcription factors by metal availability can be attested to conformational changes that are governed by both dynamics and thermodynamics. Due to the influential nature of transcription factors, their activity and activation mode have become …


Synergistic Adsorption Of Pb (Ii) From Aqueous Solution Using Calcined Biochar-Bentonite Clay Hybrid, Azeezat Faderera Abdul-Raheem Dec 2024

Synergistic Adsorption Of Pb (Ii) From Aqueous Solution Using Calcined Biochar-Bentonite Clay Hybrid, Azeezat Faderera Abdul-Raheem

Theses and Dissertations

The biochar-bentonite clay hybrid was prepared by coprecipitation with the goal of producing a material that can remove Pb (II) from aqueous solutions effectively. Incorporating bentonite clay onto the Douglas fir biochar (DFB-BTC) surface significantly improved the adsorption capacity by introducing more active sites, strengthening the structural properties, and promoting strong adsorbate interactions. The point of zero charge of the adsorbent was slightly higher than that of the pristine DFBC. All sorption experiments were performed at pH 5, and the system obeyed the Langmuir adsorption isotherm. The highest Langmuir adsorption capacities observed at 298, 308, and 318 K were 48, …


Impact Of Cascading Optical Processes On Spectroscopic Quantification Of Absorption And Scattering Properties Of Samples, Pathum Dilshan De Silva Wathudura Dec 2024

Impact Of Cascading Optical Processes On Spectroscopic Quantification Of Absorption And Scattering Properties Of Samples, Pathum Dilshan De Silva Wathudura

Theses and Dissertations

Light absorption and scattering are fundamental properties of matter, particularly significant in nanoscale materials. This study explores how cascading optical processes affect the experimental measurement of absorption and scattering intensities, along with scattering depolarization, in samples containing absorbers and scatterers. The experimental UV–vis spectrum results from the combination of absorption and scattering extinction spectra. However, the maximum measurable extinction may be limited by forward scattered light. Light absorption decreases the intensity of scattered light and influences scattering depolarization. While scattering can reduce absorption along the optical path to the detector, sufficient absorption of the scattered light may counterbalance this effect, …


Investigation Of Real-Time Gaseous Thermal Decomposition Products Of Representative Per- And Polyfluoroalkyl Substances (Pfas), Kateřina Litvanová, Bethany Klemetstrud, Feng Xiao, Alena Kubatova Dec 2024

Investigation Of Real-Time Gaseous Thermal Decomposition Products Of Representative Per- And Polyfluoroalkyl Substances (Pfas), Kateřina Litvanová, Bethany Klemetstrud, Feng Xiao, Alena Kubatova

Chemistry Faculty Publications

The thermal decomposition of per- and poly fluoroalkyl substances (PFAS) is poorly understood. Here, we present an innovative, comprehensive analytical method to investigate their thermal decomposition, including perfluorocarboxylic acids (PFCAs), alcohol, sulfonates, and GenX (acid dimer), focusing on identifying their breakdown products. In this study, evolved gas analysis–mass spectrometry (EGA-MS) was used for fast real-time screening to determine the significant temperatures to be investigated with the thermal desorption-pyrolysis coupled with gas chromatography–mass spectrometry (TD-Py-GC-MS), which provided detailed information about evolved PFAS and their breakdown products. This approach enabled a systematic study of perfluorocarboxylic acids (PFCAs) ranging from C3 to …


Design, Synthesis, And Nmr-Guided Characterization Of A Targeted Covalent Inhibitor-Like Molecule Against Ivyp1 From P. Aeruginosa, Samuel Taylor Moore Dec 2024

Design, Synthesis, And Nmr-Guided Characterization Of A Targeted Covalent Inhibitor-Like Molecule Against Ivyp1 From P. Aeruginosa, Samuel Taylor Moore

Master's Theses

Multi-drug resistance poses a serious threat to future generations and historical antibiotic pipelines; consequently, the medical and economic burdens associated with treating multidrug-resistant bacteria are substantiated. In this context, P. aeruginosa (PA) emerges as one of the most significant healthcare challenges, being a leading cause of resistance-associated mortality worldwide. Despite modern efforts to combat these poor outcomes, drug-resistant cases continue to rise, and the need for novel antibiotic treatment is apparent. To this end, we investigated relevant resistance mechanisms and past antibiotic targets within PA, and in doing so, we identified relationships between peptidoglycan biology and a periplasmic protein, Inhibitor …


Investigating Student Expectations, Buy-In, And Engagement In Lower Division Undergraduate Chemistry Labs, Elizabeth Blanche Vaughan Dec 2024

Investigating Student Expectations, Buy-In, And Engagement In Lower Division Undergraduate Chemistry Labs, Elizabeth Blanche Vaughan

Dissertations and Theses

Laboratory courses constitute an integral aspect of chemistry education at the undergraduate level. Despite their prominence, a growing number of researchers have begun to think more critically about the value of laboratory learning experiences. As pedagogical decisions should be based on evidence, it is necessary for chemistry education researchers and practitioners to investigate the claim that teaching laboratories are a valuable part of science education. Therefore, the aim of this dissertation was to address one small section of this gap in the literature by obtaining a more robust understanding of students' expectations, buy-in, and engagement in lower division, undergraduate, chemistry …


Exfoliated Hydrotalcite-Transition Metal Complex Composite For Eco-Friendly And Efficient Catalytic Degradation Of 4-Nitrophenol, Sidra Khan, Najma Memon, Saima Q. Memon, Yilmaz Yurekli Dec 2024

Exfoliated Hydrotalcite-Transition Metal Complex Composite For Eco-Friendly And Efficient Catalytic Degradation Of 4-Nitrophenol, Sidra Khan, Najma Memon, Saima Q. Memon, Yilmaz Yurekli

Karbala International Journal of Modern Science

Nitrophenols are notorious aquatic organic contaminants found as degradation products of various parent compounds, including pesticides and industrial chemicals that persist in the environment and must be removed. Catalytic degradation is one of the feasible routes to clean the contaminated water systems, however, environmental contamination with catalysts is also widespread. Herein, we report an environmentally friendly catalyst based on composited Fe-Schiff’s base with exfoliated layered double hydroxides (LDH) of aluminum and nickel (hydrotalcite). The composite showed agglomerated pleated LDH structures sheathed with Fe(III)SB. Nitrogen adsorption isotherm data exhibited improved surface area and narrow pores patterns for composite as compared to …


The Utilization Of Alcohol Dehydrogenase (Adh) Enzymes In Stereocontrolled Synthesis, Gaurav Pramod Kudalkar Dec 2024

The Utilization Of Alcohol Dehydrogenase (Adh) Enzymes In Stereocontrolled Synthesis, Gaurav Pramod Kudalkar

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Clostridium acetobutylicum alcohol dehydrogenase (CaADH) has been shown to catalyze the stereoselective reduction of a broad array of carbonyl compounds. This study uses a Hammett linear free-energy relationship (LFER) analysis to gain insight into CaADH enzyme mechanism across three substrate classes: aryl aldehydes, aryl β-keto esters, and aryl trifluoromethyl ketones. Kinetic data were collected by monitoring NADPH fluorescence, and Michaelis-Menten kinetics were applied. Hammett plots reveal that hydride transfer is rate-limiting for aldehydes and β-keto esters (ρ > 0), while it is proposed that dehydration is rate-limiting for trifluoromethyl ketones (ρ < 0). 13C NMR confirmed significant hydration in trifluoromethyl ketones. The …


Physical Properties Of Aqueous Imide-Based Electrolyte Solutions, Mollie Harr Dec 2024

Physical Properties Of Aqueous Imide-Based Electrolyte Solutions, Mollie Harr

Honors Capstones

In order to observe the effects that cations have on the physical properties of -TFSI [-bis(trifluoromethane sulfonyl)imide] based salts, four salts (LiTFSI, NaTFSI, Mg(TFSI)2, and Al(TFSI)3) were selected for testing. The data gathered shows that when the anion is large and bulky like -TFSI, the size of the cation does not have a large effect on the physical properties, but the oxidation state of the cation may have a significant effect. The ion-ion interactions, such as collisions, aggregation, and repulsion are more significant when the cation has a higher oxidation state due to the increased ratio of anion per molecule …


Increased Thermal Stability And Retained Antibacterial Properties In A Sulbactam And Amantadine Salt: Towards Effective Antibacterial-Antiviral Combination Therapies, Josephine Bicknell, Ivan Bondarenko, Alice Colatrella, Elani J. Cabrera-Vega, Jesus Daniel Loya, Delbert S. Botes, Jay L. Mellies, Gonzalo Campillo-Alvarado Dec 2024

Increased Thermal Stability And Retained Antibacterial Properties In A Sulbactam And Amantadine Salt: Towards Effective Antibacterial-Antiviral Combination Therapies, Josephine Bicknell, Ivan Bondarenko, Alice Colatrella, Elani J. Cabrera-Vega, Jesus Daniel Loya, Delbert S. Botes, Jay L. Mellies, Gonzalo Campillo-Alvarado

Chemistry Faculty Publications and Presentations

A clinically relevant multidrug solid comprising sulbactam (β-lactamase inhibitor) and amantadine (antiviral) displays enhanced thermal stability and sustained antibacterial activity compared to starting materials.

We describe the formation of a multidrug salt comprising sulbactam (SUL, β-lactamase inhibitor) and amantadine (AMNH, antiviral). Physicochemical investigation of the SUL·AMNH salt revealed enhanced thermal stability compared to pristine starting materials. In vitro studies found that salt formation in SUL·AMNH does not disrupt antibacterial activity against model organisms Escherichia coli and Staphylococcus epidermidis. To our knowledge, we show the first β-lactamase inhibitor-antiviral salt where both components have been approved by the U.S. Food and Drug …


Synthesis And Characterization Of Metal-Organic Framework Nanostructures And Evaluation Of Their Photocatalytic Activity, James Kegere Dec 2024

Synthesis And Characterization Of Metal-Organic Framework Nanostructures And Evaluation Of Their Photocatalytic Activity, James Kegere

Thesis/ Dissertation Defenses

Reticular materials have enlisted tremendous interest from researchers across the globe in the last two decades. This heightened interest stems from the novelty in structure and chemistry that renders them peerless in multiple fields such as medicine, energy, and environment. On the environmental research front these materials have found applications in mitigation of different pollutants such as CO2 which is the most important greenhouse gas through storage and conversion, catalysis of CO2 conversion into useful products. Furthermore, these materials have also proven to be effective sorbent materials for many toxic compounds that find their way into freshwater systems …


Na2B12Si6Se18: A Novel B12-Cluster-Containing Quaternary Selenoborate Framework Material, Gopabandhu Panigrahi, Hunter B. Tisdale, Gregory Morrison, Hans Conrad Zur Loye Dec 2024

Na2B12Si6Se18: A Novel B12-Cluster-Containing Quaternary Selenoborate Framework Material, Gopabandhu Panigrahi, Hunter B. Tisdale, Gregory Morrison, Hans Conrad Zur Loye

Faculty Publications

We report the successful synthesis of the new quaternary, three-dimensional Na2B12Si6Se18 material using a solid-state synthesis route. This compound is characterized by a unique framework structure that features the rare icosahedral [B12]10+ cation which is connected via Si2Se6 polyhedral units into a 3D framework structure with Na+ ions located inside the channels. The Na2B12Si6Se18 compound crystallizes in the cubic crystal system in the space group Im, with lattice parameter a = 11.91110(10) Å and unit cell volume of 1689.88(4) Å3. …


Development Of A Rapid Method For Pfas Detection And Quantitation In Human Hair, Justin M. Allen Dec 2024

Development Of A Rapid Method For Pfas Detection And Quantitation In Human Hair, Justin M. Allen

Student Theses

In recent years, per- and polyfluoroalkyl substances (PFAS) have emerged as a critical focus in environmental and public health research due to their persistent nature and widespread use in products ranging from non-stick cookware to firefighting foams. These "forever chemicals" resist degradation, posing significant ecological and human health risks. While extensive studies have explored PFAS in environmental matrices, research into their presence in human hair remains limited, with only a handful of studies addressing this biomarker's potential. This thesis aims to develop a robust analytical method for detecting PFAS in human hair, leveraging its unique properties to provide a long-term …