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Articles 2701 - 2730 of 33132

Full-Text Articles in Chemistry

Chemical Strategies For Tailoring Properties Of Nanomaterials Produced By Pulsed Laser Interaction In Liquid Environments, Katharine M. Tibbetts Jan 2024

Chemical Strategies For Tailoring Properties Of Nanomaterials Produced By Pulsed Laser Interaction In Liquid Environments, Katharine M. Tibbetts

Chemistry Publications

Interactions of intense ultrashort laser pulses with liquid media and at solid-liquid interfaces produce plasmas with high densities of reactive chemical species that promote the formation of nanomaterials. This work discusses the current understanding of laser-induced chemical reactions in aqueous medium involving hydrated electrons and hydroxyl radicals, and the effects of chemical additives on these reactions. Two chemical strategies are presented for controlling the composition of the laser-induced plasma and nanomaterial properties. First, adding chemical scavengers of hydroxyl radicals will be shown to inhibit metal oxidation, enabling the synthesis of ligand-free Ag and Au-Ag alloy nanoparticles by reduction of Au …

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Zno Varistors—Preparation Of Nano And Micro Sized Powders By Mechanical Methods For Low And High Voltage Varistors, Maura Kelleher Jan 2024

Zno Varistors—Preparation Of Nano And Micro Sized Powders By Mechanical Methods For Low And High Voltage Varistors, Maura Kelleher

Books/Book Chapters

ZnO-Bi2O3-Sb2O3 varistors are as essential today as they have been since their discovery five decades ago. Their role is to protect other electronic components against oncoming surges of electrons and survive. The demands on varistors are increasing. Electronic components are becoming smaller and more sensitive, and the metal oxides from which varistors are made are precious. Every aspect of their structure (macro, micro, nano and atomic) determines how they perform and survive. Each stage and variable within the powder metallurgy process is important. The mechanical methods in preparing nano and micro sized metal oxide powders are outlined in this chapter.

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A Qualitative Inquiry To The Impact Of Peer Teaching On Undergraduate Chemistry Students, Marcus Sambar Jan 2024

A Qualitative Inquiry To The Impact Of Peer Teaching On Undergraduate Chemistry Students, Marcus Sambar

Theses and Dissertations

This study investigates the impact of peer teaching on undergraduate STEM majors, particularly those who serve as peer teachers for introductory chemistry courses. While previous research has predominantly focused on the benefits of peer tutoring for the tutored students, the reciprocal impact on peer teachers remains underexplored. The main purpose of this study is to quantify the differences between peer teachers and comparable students who do not engage in teaching, with a specific focus on problem-solving approaches and the ability to explain STEM concepts. The assessment included coding students' work to reveal strategy use and provide a means of comparison …

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Research Trends And Impact Report On Aggregation-Induced Emission (Aie), 2001-2021, Elsevier Analytical Services Jan 2024

Research Trends And Impact Report On Aggregation-Induced Emission (Aie), 2001-2021, Elsevier Analytical Services

Public Reports

Since the concept of AIE was first proposed in China in 2001, it has gradually grown to a field of science that attracts dedicated researchers from around the world. Elsevier's data analytics team used AIE experts' interpretation of current theoretical, technological, and industrial development trends in the field for reference to collect AIE-related global scientific publications (from the Scopus database) to serve as a publication set in the field of AIE. This was undertaken to present, accurately and objectively, the development of AIE research over the past two decades and the latest scientific advancements in the field; to facilitate the …

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Mechanism Of Protein Aggregation Inhibition By Arginine: Blockage Of Anionic Side Chains Favors Unproductive Encounter Complexes, Lars Konermann, Yuen K. Ng Jan 2024

Mechanism Of Protein Aggregation Inhibition By Arginine: Blockage Of Anionic Side Chains Favors Unproductive Encounter Complexes, Lars Konermann, Yuen K. Ng

Chemistry Publications

Aggregation refers to the assembly of proteins into non-physiological higher order structures. While amyloid has been studied extensively, much less is known about amorphous aggregation, a process that interferes with protein expression and storage. Free arginine (Arg+) is a widely used aggregation inhibitor, but its mechanism remains elusive. Focusing on myoglobin (Mb), we recently applied atomistic molecular dynamics (MD) simulations for gaining detailed insights into amorphous aggregation (Ng et al., J. Phys. Chem. B 2021, 125, 13099). Building on that approach, the current work for the first time demonstrates that MD simulations can directly elucidate aggregation …

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Md Simulations Of Peptide-Containing Electrospray Droplets: Effects Of Parameter Settings On The Predicted Mechanisms Of Gas Phase Ion Formation, Lars Konermann, Kasra Hanifi, Pablo M. Scrosati Jan 2024

Md Simulations Of Peptide-Containing Electrospray Droplets: Effects Of Parameter Settings On The Predicted Mechanisms Of Gas Phase Ion Formation, Lars Konermann, Kasra Hanifi, Pablo M. Scrosati

Chemistry Publications

Electrospray ionization (ESI) mass spectrometry (MS) is widely used for interrogating peptides, proteins, and other biomolecular analytes. A growing number of laboratories use molecular dynamics (MD) simulations for uncovering ESI mechanisms by modeling the behavior of highly charged nanodroplets. The outcome of any MD simulation depends on certain assumptions and parameter settings, and it is desirable to optimize these factors by benchmarking computational data against experiments. Unfortunately, benchmarking of ESI simulations is difficult, because experimentally generated gaseous ions do not generally retain any features that would reveal their formation pathway [e.g., the charged residue mechanism (CRM) or the ion evaporation …

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Aggregation And Oligomerization Characterization Of Ss-Lactoglobulin Protein Using A Solid-State Nanopore Sensor, Mitu C. Acharjee, Brad Ledden, Brian Thomas, Xianglan He, Troy Messina, Jason Giurleo, David Talaga, Jiali Li Jan 2024

Aggregation And Oligomerization Characterization Of Ss-Lactoglobulin Protein Using A Solid-State Nanopore Sensor, Mitu C. Acharjee, Brad Ledden, Brian Thomas, Xianglan He, Troy Messina, Jason Giurleo, David Talaga, Jiali Li

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Protein aggregation is linked to many chronic and devastating neurodegenerative human diseases and is strongly associated with aging. This work demonstrates that protein aggregation and oligomerization can be evaluated by a solid-state nanopore method at the single molecule level. A silicon nitride nanopore sensor was used to characterize both the amyloidogenic and native-state oligomerization of a model protein ß-lactoglobulin variant A (βLGa). The findings from the nanopore measurements are validated against atomic force microscopy (AFM) and dynamic light scattering (DLS) data, comparing βLGa aggregation from the same samples at various stages. By calibrating with linear and circular dsDNA, this study …

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Evolution Of A Self-Renewing, Participant-Centered Workshop Series In Bmb Assessment, Ludmila Tyler, Peter J. Kennelly, Shelly Engelman, Kirsten F. Block, Jennifer C. Bobenko, Jaclyn Catalano, Jesica A. Jones, Margaret I. Kanipes-Spinks, Yang Mooi Lim, Jennifer Loertscher, Tejiri Olafimihan, Hailey Reiss, Territa L. Upchurch-Poole, Yufeng Wei, Kimberly J. Linenberger Cortes, Victoria Del Gaizo Moore Jan 2024

Evolution Of A Self-Renewing, Participant-Centered Workshop Series In Bmb Assessment, Ludmila Tyler, Peter J. Kennelly, Shelly Engelman, Kirsten F. Block, Jennifer C. Bobenko, Jaclyn Catalano, Jesica A. Jones, Margaret I. Kanipes-Spinks, Yang Mooi Lim, Jennifer Loertscher, Tejiri Olafimihan, Hailey Reiss, Territa L. Upchurch-Poole, Yufeng Wei, Kimberly J. Linenberger Cortes, Victoria Del Gaizo Moore

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

We present as a case study the evolution of a series of participant-centered workshops designed to meet a need in the life sciences education community—the incorporation of best practices in the assessment of student learning. Initially, the ICABL (Inclusive Community for the Assessment of Biochemistry and Molecular Biology/BMB Learning) project arose from a grass-roots effort to develop material for a national exam in biochemistry and molecular biology. ICABL has since evolved into a community of practice in which participants themselves—through extensive peer review and reflection—become integral stakeholders in the workshops. To examine this evolution, this case study begins with a …

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Efficient Sabre-Sheath Hyperpolarization Of Pyruvate And Other Alpha-Ketocarboxylates And Ultra-High-Qualityfactor Wireless Masing Magnetic Resonance Sensing Of Hyperpolarized Contrast Media, Isaiah Olabisi Adelabu Jan 2024

Efficient Sabre-Sheath Hyperpolarization Of Pyruvate And Other Alpha-Ketocarboxylates And Ultra-High-Qualityfactor Wireless Masing Magnetic Resonance Sensing Of Hyperpolarized Contrast Media, Isaiah Olabisi Adelabu

Wayne State University Dissertations

Over the years, there has been research geared towards mitigating disease conditions such as cancers and tumors by molecular sensing of their aberrant metabolism in humans and animal models of diseases. Some of these biomolecules of interest are pyruvate, α-ketoglutarate, and ketoisocaproate, that play a central role in eukaryotic and human metabolic pathways. Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) have become predominant in investigating and imaging cancers and tumors for early detection and treatment. Although conventional NMR spectroscopy is limited by low sensitivity, we overcame this barrier through the use of hyperpolarization techniques. NMR hyperpolarization improves …

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Development Of Microfluidic Thermal Gel Electrophoresis For Biological Analysis, Mario Ambrocio Cornejo Jan 2024

Development Of Microfluidic Thermal Gel Electrophoresis For Biological Analysis, Mario Ambrocio Cornejo

Wayne State University Dissertations

ABSTRACTDEVELOPMENT OF MICROFLUIDIC THERMAL GEL ELECTROPHORESIS FOR BIOLOGICAL ANALYSIS by MARIO AMBROCIO CORNEJO May 2024 Advisor: Dr. Thomas H. Linz Major: Chemistry (Analytical Chemistry) Degree: Doctor of Philosophy The molecular biology that takes place within cells is vital to the over function of an organism. Healthy cellular function is crucial to a wide web of interconnected processes that need to be balanced and regulated. When these processes become abnormal, disease states are developed. The mapping of biological networks has led to the development of gene therapy and more accurate diagnostic tests. However, there are still vital biomolecules that due to …

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Exploiting Light To Probe Biological Processes, Madeline Denison Jan 2024

Exploiting Light To Probe Biological Processes, Madeline Denison

Wayne State University Dissertations

Metal complexes have many advantages as biochemical tools due to their rich photophysical properties and unique geometry. Metal-based complexes are commonly reported as emissive probes or photoactivatable biological agents. Long emission lifetimes of metal complexes allow for the use of lifetime gating which eliminates autofluorescence found in assays, a distinct advantage over short-lived organic fluorophores. This work utilizes this powerful technique to generate reversible, emissive probes for monitoring CYP3A4 active site occupancy. In addition to the emissive properties of metals, metals can also be used as photodynamic therapy (PDT) and photochemotherapy (PCT) agents. These light-activated strategies provide important spatiotemporal control …

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Visible Light Photocatalysis With Quantum Dot Gel For Organic Synthesis, Daohua Liu Jan 2024

Visible Light Photocatalysis With Quantum Dot Gel For Organic Synthesis, Daohua Liu

Wayne State University Dissertations

This dissertation presents metal chalcogenide quantum dots (QDs), a group of emerging visible light photocatalysts, for unique organic chemical transformations that are impossible using conventional molecular photocatalysts. The first part of this dissertation focuses on the comparison between ligand-capped CdS QD and CdS gel. CdS QD gel is a three-dimensional network of interconnected QD. CdS gels were found to show more facile charge transfer with substrates than QDs, due to the partial removal of ligands from its surface during gelation. Our study showed that the photocatalytic activity of CdS gels was indeed superior to trioctylphosphine (TOP)- and thioglycolic acid (TGA)-capped …

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Nanoscale Studies Of Magnesium Carbonate Precipitation At Ambient Conditions, Ian Shortt Jan 2024

Nanoscale Studies Of Magnesium Carbonate Precipitation At Ambient Conditions, Ian Shortt

Material Science and Engineering Dissertations - Archive

Currently approximately 8% of global greenhouse gas emissions can be attributed to the construction industry; of these emissions, a little over half of these emissions are due to the production of traditional calcium-based cements. Magnesium carbonate cements present a promising alternative to traditional calcium-based cements, both in terms of emission reductions and in terms of strength. The primary drawback to magnesium carbonate cements is that ambient curing is not yet viable. The objective of this dissertation is to therefore develop greater understanding of the precipitation pathways undertaken by hydrated magnesium carbonates under near-ambient conditions. In the first section of this …

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Chemoselective Reduction Of Dicarboxylic Acids Via Iridium Catalyzed Hydrosilylation, Linda Lallawmsangi Jan 2024

Chemoselective Reduction Of Dicarboxylic Acids Via Iridium Catalyzed Hydrosilylation, Linda Lallawmsangi

Chemistry & Biochemistry Theses - Archive

Reduction of esters to aldehydes poses a challenge since the resulting aldehydes are often more reactive than the initial esters toward nucleophilic hydride-reducing agents. Although bulky, more controllable reducing agents such as lithium tri-tert-butoxyaluminum hydride or diisobutylaluminum hydride (DIBAL-H) have been developed, they are hazardous, sensitive to moisture and air, needing strict reaction conditions, and unsuitable with a wide range of functional groups. We present the design of an iridium-catalyzed chemoselective hydrosilylation method for dicarboxylic imides, followed by hydrolysis to eliminate the amide and yield aldehydes. This approach offers versatility in general reduction chemistry, holds promise for application …

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Quantum Interference Enhancement Of The Spin-Dependent Thermoelectric Response, Runa X. Bennett, Joshua R. Hendrickson, Justin P. Bergfield Jan 2024

Quantum Interference Enhancement Of The Spin-Dependent Thermoelectric Response, Runa X. Bennett, Joshua R. Hendrickson, Justin P. Bergfield

Faculty publications – Physics

We investigate the influence of quantum interference (QI) and broken spin-symmetry on the thermoelectric response of node-possessing junctions, finding a dramatic enhancement of the spin-thermopower (Ss), figure-of-merit (ZsT), and maximum thermodynamic efficiency (ηsmax) caused by destructive QI. Using many-body and single-particle methods, we calculate the response of 1,3-benzenedithiol and cross-conjugated molecule-based junctions subject to an applied magnetic field, finding nearly universal behavior over a range of junction parameters with Ss, ZsT, and reaching peak values of 2𝜋/ √3(𝑘/𝑒)2𝜋/3(𝑘/𝑒), 1.51, and 28% of Carnot efficiency, respectively. We also find that the …

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Sequential Infiltration Synthesis Of Silicon Dioxide In Polymers With Ester Groups─Insight From In Situ Infrared Spectroscopy, Mahua Biswas, Vepa Rozyyev, Anil U. Mane, Amelia Korveziroska, Uttam Manna, Jeffrey W. Elam Jan 2024

Sequential Infiltration Synthesis Of Silicon Dioxide In Polymers With Ester Groups─Insight From In Situ Infrared Spectroscopy, Mahua Biswas, Vepa Rozyyev, Anil U. Mane, Amelia Korveziroska, Uttam Manna, Jeffrey W. Elam

Faculty publications – Physics

New strategies to synthesize nanometer-scale silicon dioxide (SiO2) patterns have drawn much attention in applications such as microelectronic and optoelectronic devices, membranes, and sensors, as we are approaching device dimensions shrinking below 10 nm. In this regard, sequential infiltration synthesis (SIS), a two-step gas-phase molecular assembly process that enables localized inorganic material growth in the targeted reactive domains of polymers, is an attractive process. In this work, we performed in situ Fourier transform infrared spectroscopy (FTIR) measurements during SiO2 SIS to investigate the reaction mechanism of trimethylaluminum (TMA) and tri(tert-pentoxy) silanol (TPS) precursors with polymers having ester functional groups (poly(methyl …

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Synthesis Of Novel 5-Aryl 2’-Deoxyuridine And 2’-Deoxycytidine Analogues, Kevin E. Persaud Jan 2024

Synthesis Of Novel 5-Aryl 2’-Deoxyuridine And 2’-Deoxycytidine Analogues, Kevin E. Persaud

Dissertations and Theses

Briefly, the following report details a synthetic route to prepare 5-phenyl-2’-deoxycytidine analogues. This multistep synthesis began with silyl protection of the 3’- and 5’-hydroxyl groups of 5-iodo-2’-deoxyuridine. Next, the installation of a phenyl ring at the C5 position of the nucleobase via a Suzuki-Miyaura cross-coupling reaction, yielding 5-phenyl-2’-deoxyuridine (5-PdU). After that, modification of the obtained 5-PdU at the C4 position was performed with benzotriazole-1-yl-oxy-tris-(dimethylamino)-phosphonium hexafluorophosphate (BOP, a peptide-coupling agent) and a base (cesium carbonate) to activate the amide group of the uridine nucleobase for subsequent displacement with a variety of amines. Modification of the C4 position resulted in protected 5-phenyl-2’-deoxycytidine …

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Validating Machine And Human Decision-Making In Forensic Fire Debris Analysis, Frances A. Whitehead Jan 2024

Validating Machine And Human Decision-Making In Forensic Fire Debris Analysis, Frances A. Whitehead

Graduate Thesis and Dissertation 2023-2024

This work presents a background on the chemical complexity of fire debris analysis, including an ever-present matrix of pyrolysis products as the catalyst that led to the creation of the National Center for Forensic Science's Fire Debris Database. A selection of these 1,000+ casework-relevant ground truth samples was used to create two newly proposed analyst workflows to connect the current method of categorical reporting with evaluative reporting practices reflective of the strength of the evidence. Both workflows use linear sequential unmasking to help mitigate bias, a discrete scoring system for quantification of the analysis, and receiver operating characteristic (ROC) curves …

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Thermosensitive Phosphors As Optical Temperature Sensors In Extreme Environments, Marcos Ramon Imer Rocha Pita Jan 2024

Thermosensitive Phosphors As Optical Temperature Sensors In Extreme Environments, Marcos Ramon Imer Rocha Pita

Wayne State University Dissertations

Luminescent temperature sensors offer unique advantages over thermocouples and pyrometers for applications in extreme environments such as operando wall temperature mapping of combustion engines. A refractory oxide host doped with an optically active ion has the potential to afford a thermosensitive phosphor with a well-defined temperature response in such extreme environments. However, the design of thermosensitive phosphors with targeted temperature sensitivity and spatial resolution in the operational temperature range of interest has been hindered by the inability to rationally select host–activator pairs. A major scientific question is what crystal-chemistry features a low thermal conductivity oxide must possess to afford a …

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Density Functional Studies Of Molecular Separation And Charge Transport, Timothy Quainoo Jan 2024

Density Functional Studies Of Molecular Separation And Charge Transport, Timothy Quainoo

Wayne State University Dissertations

This thesis presents a series of studies which can be grouped majorly into two sections both focusing on the utilization of density functional theory techniques; Molecular electronics and Molecular separation. Molecular electronics has been anticipated to hold a great future as it seeks to apply molecular building blocks in the creation of electronic components. On the other hand, the utilization of mild conditions in chemical processes is geared toward the major goals of green chemistry as it produces less waste and is cost-effective. Thus, this dissertation tackles and answers some of the unanswered questions in literature by using theoretical methods …

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Design And Synthesis Of Aminoglycoside-Based Heparan Sulfate Mimetics For Structure-Activity Relationship Studies Of Heparan-Binding Proteins, Joseph Wakpal Jan 2024

Design And Synthesis Of Aminoglycoside-Based Heparan Sulfate Mimetics For Structure-Activity Relationship Studies Of Heparan-Binding Proteins, Joseph Wakpal

Wayne State University Dissertations

Cancer remains a formidable challenge in modern medicine, demanding innovative approaches and treatments. Among the emerging strategies, inhibiting heparanase and fibroblast growth factor 2 (FGF2) has garnered considerable attention in recent years. This dissertation presents a novel approach to designing and synthesizing a diverse library of heparan sulfate (HS) mimetics derived from aminoglycosides to study their binding to two heparin-binding proteins involved in cancer development and metastasis. Heparanase cleaves HS polysaccharide chains in the extracellular matrix (ECM) and is a regulator of aggressive tumor behavior. Clinical studies have illustrated that aberrant heparanase expression correlates with increased tumor size, amplified tumor …

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Sustainable Additive Manufacturing Of Polysulfone Membranes For Liquid Separations, Brian Leonard, Harrison Loh, David Lu, Ebuka A. Ogbuoji, Isabel Escobar, Konstantinos Sierros, Oishi Sanyal Jan 2024

Sustainable Additive Manufacturing Of Polysulfone Membranes For Liquid Separations, Brian Leonard, Harrison Loh, David Lu, Ebuka A. Ogbuoji, Isabel Escobar, Konstantinos Sierros, Oishi Sanyal

UK CARES Faculty Publications

Membranes serve as important components for modern manufacturing and purification processes but are conventionally associated with excessive solvent usage. Here, for the first time, a procedure for fabricating large area polysulfone membranes is demonstrated via the combination of direct ink writing (DIW) with non-solvent induced phase inversion (NIPS). The superior control and precision of this process allows for complete utilization of the polymer dope solution during membrane fabrication, thus enabling a significant reduction in material usage. Compared to doctor blade fabrication, a 63% reduction in dope solution volume was achieved using the DIW technique for fabricating similarly sized membranes. Cross …

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Temperature-Dependent Stress–Strain Behavior Of Amorphous And Crystalline P3ht, Kehinde H. Fagbohungbe, Connor P. Callaway, Chad Risko Jan 2024

Temperature-Dependent Stress–Strain Behavior Of Amorphous And Crystalline P3ht, Kehinde H. Fagbohungbe, Connor P. Callaway, Chad Risko

UK CARES Faculty Publications

The scalable commercialization of organic electronics wherein p-conjugated polymers serve as the semiconductors hinges on precise control of the material electronic, redox, optical, and mechanical properties, which are each highly influenced by local and long-range morphology. Here, we undertake atomistic molecular dynamics (MD) simulations at three temperatures (150 K, 300 K, and 400 K) to assess the morphological and mechanical response of bulk poly(3-hexylthiophene) (P3HT), a representative homopolymer of interest as an organic semiconductor (OS). As P3HT is a semicrystalline polymer, we characterize mechanical properties for both amorphous and crystalline P3HT models to derive insights into structure–property relationships, including Young’s …

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Solution Combustion Synthesis And Characterization Of Fumarolic Mineral Dolerophanite, Copper (Ii) Oxide Sulfate, Eric J. Cyganowski Jan 2024

Solution Combustion Synthesis And Characterization Of Fumarolic Mineral Dolerophanite, Copper (Ii) Oxide Sulfate, Eric J. Cyganowski

Chemistry & Biochemistry Theses - Archive

Dolerophanite Cu2OSO4 is a rare mineral found almost exclusively in the fumaroles of volcano systems and is sensitive to temperature and humidity conditions. It has a monoclinic C2/m crystal structure characterized by two-dimensional layers composed of sulfate anions dispersed amongst copper (II) oxide backbones. There has been recent interest in dolerophanite due to the magnetic properties of its Kagome-like lattice as well as its potential use as a photocatalyst or Li-ion battery electrode. Literature on the material however has been limited by the available synthesis strategies. As such, this thesis work presents a novel strategy …

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Calcium Carbonate-Based Stimuli-Responsive Microcarriers For Targeted Drug Delivery Against Oral Bacterial Infections And Development Of Glass-Free Microfluidics As An Analytical Platform, Krishantha Wijewardhane Jan 2024

Calcium Carbonate-Based Stimuli-Responsive Microcarriers For Targeted Drug Delivery Against Oral Bacterial Infections And Development Of Glass-Free Microfluidics As An Analytical Platform, Krishantha Wijewardhane

Dissertations and Theses

Dental diseases present a significant global health challenge, affecting individuals across all age groups. This spectrum of oral health issues encompasses conditions like dental caries, periodontitis (gum disease), and oral infections. In the customer discovery interviews, dental patients have raised concerns about potential drug overexposure during and after procedures, driven by fears of adverse effects, allergies, and the increasing use of antibiotics and anesthesia. Dentists are increasingly focused on minimizing opioid and steroid-based medication doses due to potential side effects and addiction risks. This study explores an innovative approach to targeted drug delivery in the dental environment using eco-friendly and …

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Structural Modification Of 4'-Aminochalcones As Α-Glucosidase Inhibitors, Emmanuel Sunday Idoko Jan 2024

Structural Modification Of 4'-Aminochalcones As Α-Glucosidase Inhibitors, Emmanuel Sunday Idoko

Chulalongkorn University Theses and Dissertations (Chula ETD)

Diabetes mellitus, one of the most predominant health problems worldwide, characterized by hyperglycemia, has attracted the attention of medicinal chemists. Although several therapeutic drugs have been developed and used clinically, diabetes continues to pose a growing threat to public health. One of the promising approaches for treating type 2 diabetes involves reducing the rate of carbohydrate hydrolysis by inhibiting the action of α-glucosidase. Over the years, chalcone analogues have been reported for their vast biological properties and as a promising antidiabetic agent. In this research, two series of 4'-aminochalcone derivatives were designed and synthesized as α-glucosidase inhibitors. Twenty-five alkylated 4'-aminochalcone …

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High Purity Silver Nano- And Micro Particles With Controllable Shapes By Polymeric Stabilizers, Natsuda Muankhajorn Jan 2024

High Purity Silver Nano- And Micro Particles With Controllable Shapes By Polymeric Stabilizers, Natsuda Muankhajorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work presents a rapid, sustainable, and efficient technique for both recovering silver microstructures from spent button batteries and fabricating flexible conductive materials. In the first phase, a green recovery method was developed using H2O2 as a reducing agent to convert silver sources into high-purity silver microstructures. The morphology of the recovered silver was controlled using polymeric stabilizers (PVP and PVA) whose molecular weights significantly influenced particle shape and aggregation. PVP promoted the formation of uniform silver microplates, while PVA yielded isotropic microspheres. The silver microstructures from the spent button batteries were converted into highly pure silver microstructures (>98%), …

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A Breast Cancer Stem Active Cobalt(Iii)-Cyclam Complex Containing Flufenamic Acid With Immunogenic Potential, Jiaxin Fang, Owamagbe N. Orobator, Chibuzor Ngozi Olelewe, Ginevra Passeri, Kuldip Singh, Samuel G. Awuah, Kogularamanan Suntharalingam Jan 2024

A Breast Cancer Stem Active Cobalt(Iii)-Cyclam Complex Containing Flufenamic Acid With Immunogenic Potential, Jiaxin Fang, Owamagbe N. Orobator, Chibuzor Ngozi Olelewe, Ginevra Passeri, Kuldip Singh, Samuel G. Awuah, Kogularamanan Suntharalingam

Chemistry Faculty Publications

The cytotoxic and immunogenic-activating properties of a cobalt(III)-cyclam complex bearing the non-steroidal anti-inflammatory drug, flufenamic acid is reported within the context of anti-cancer stem cell (CSC) drug discovery. The cobalt(III)-cyclam complex 1 displays sub-micromolar potency towards breast CSCs grown in monolayers, 24-fold and 31-fold greater than salinomycin (an established anti-breast CSC agent) and cisplatin (an anticancer metallopharmaceutical), respectively. Strikingly, the cobalt(III)-cyclam complex 1 is 69-fold and 50-fold more potent than salinomycin and cisplatin towards three-dimensionally cultured breast CSC mammospheres. Mechanistic studies reveal that 1 induces DNA damage, inhibits cyclooxygenase-2 expression, and prompts caspase-dependent apoptosis. Breast CSCs treated with 1 exhibit …

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Unusual Eluents, Small Systems, And Digital Signal Processing For Highly Efficient Greener Separations, Troy T. Handlovic Jan 2024

Unusual Eluents, Small Systems, And Digital Signal Processing For Highly Efficient Greener Separations, Troy T. Handlovic

Chemistry & Biochemistry Dissertations - Archive

Separation science is a rapidly evolving field, where routine analyses are now done at speeds and efficiencies not thought to be possible several years ago. The tangential field of green analytical chemistry is evolving at an even faster rate and can be considered to be in its infancy stage. As green analytical chemistry is better understood, the greenness of a method will be considered during standard method development just as resolution, sensitivity, and efficiency are considered now. The first portion of this dissertation focuses on the development of mathematical and pragmatic methods to minimize the analytical method greenness score, and …

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Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss Jan 2024

Development Of Vacuum-Assisted Headspace High-Capacity Solid-Phase Microextraction For The Determination Of Semi-Volatile Compounds From Samples At Lower Temperatures, Shannon L. Thomas, Kevin A. Schug, Colton Myers, Jason S. Herrington, Reagan L. Miller, Anush Pabley, Frank W. Foss

Chemistry & Biochemistry Dissertations - Archive

Vacuum-assisted headspace solid-phase microextraction (Vac-HS-SPME) is a method used to increase solid-phase microextraction sampling of semi-volatile organic compounds. Three studies were conducted using Vac-HS-SPME via gas chromatography - mass spectrometry (GC-MS) methods for analysis of various sample types. First, a study was performed using Vac- HS-SPME combined with a high-capacity (HC) SPME Arrow to determine the operational fundamentals and workflow necessary to achieve optimal extraction of semi-volatile compounds from a model solid matrix (Ottawa sand). The fundamentals investigated included the seals necessary to create a leak-free sampling vial under vacuum conditions; the magnitude of the vacuum exerted, and the time …

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