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Articles 5401 - 5430 of 33149

Full-Text Articles in Chemistry

Bioactivity Of Suberitenones A And B, Jared G. Waters Apr 2022

Bioactivity Of Suberitenones A And B, Jared G. Waters

USF Tampa Graduate Theses and Dissertations

Throughout human history, natural products have formed the foundation of medicine. In ancient times, a myriad of herbs and fungi have been attributed properties of healing and rejuvenation. Today, that foundation still very much exists, as natural product chemists isolate bioactive compounds from plants, fungi, animals, and microorganisms alike. As more of these secondary metabolites are discovered, scientists pursue more and more sources of biodiversity that may yield new and unprecedented compounds. To this end, Antarctica has become of particular note, as its unique environmental conditions and highly isolated nature make for rare and unusual adaptations in its native wildlife. …


The Analysis Of Microplastics Found In The Flowers Of Rhode Island, Hailey Hendricks, Matthew Kiesewetter Apr 2022

The Analysis Of Microplastics Found In The Flowers Of Rhode Island, Hailey Hendricks, Matthew Kiesewetter

Senior Honors Projects

No abstract provided.


Identification And Quantification Of Atrazine In The North River Using Spe And Hplc, Kenneth Scott Overway, Youmna Moawad Apr 2022

Identification And Quantification Of Atrazine In The North River Using Spe And Hplc, Kenneth Scott Overway, Youmna Moawad

Chemistry Faculty Scholarship

High-performance liquid chromatography (HPLC) is utilized for the separation, purification, and quantification of viscous and complex analyte mixtures. It is important in that it can analyze and detect low analyte concentrations, which can be useful in many industries, such as food and pharmaceutical industries, as well analyzing environmental samples. The purpose of this project was to identify and quantitate atrazine, an herbicide, in a water sample from the North River (Bridgewater, VA) using solid-phase extraction (SPE) and HPLC.


Comparing And Contrasting Therapeutic Drugs Vs. Lifestyle Changes That Combattype-Ii Diabetes, Alexander Cline Helmuth Apr 2022

Comparing And Contrasting Therapeutic Drugs Vs. Lifestyle Changes That Combattype-Ii Diabetes, Alexander Cline Helmuth

Chemistry & Biochemistry Student Projects

In this thesis, I will be presenting various preventive approaches to combat type-II diabetes. The focus of this paper will be comparing and contrasting therapeutic drug targets such as Metformin and Sulfonylureas that are prescribed for type-II diabetic patients versus taking preventative steps such as making lifestyle changes including weight management, physical activity, and having a balanced diet that prevents onset of type-II diabetes or helps patients manage type-II diabetes. From this paper, one will gain insight on how there are multiple approaches to combat type-II diabetes that are not in the form of the pill.


Microfluidic Paper Analytical Devices, Madison Page Apr 2022

Microfluidic Paper Analytical Devices, Madison Page

Chemistry & Biochemistry Student Projects

Microfluidic paper analytical devices (µPADs) are small, paper-based matrices similar to Lab-on-a-Chip (LOC). They are capable of semi-quantitative analysis, with applications ranging from medical to environmental to food and beverage testing. Important to improving point-of-care devices (POCs), various techniques have been integrated into µPADs to customize analysis and fit different clinical situations.


The Application Of Biological Processes To Increase Energy Potential In Landfills, Ashlyn Eisenhart Apr 2022

The Application Of Biological Processes To Increase Energy Potential In Landfills, Ashlyn Eisenhart

Chemistry & Biochemistry Student Projects

There has been a dramatic increase in the amount of waste that we humans have created. This has been due to population growth, an increase in industrial manufacturing, along with urbanization and modernization.8 The number of tons of municipal solid waste entering landfills has increased from 82.5 million tons in 1960 to 146.1 million tons in 2018.17 However, thanks to recycling, composting, and energy recovery from combustion, the percentage of solid waste going to landfills has dramatically decreased, from around 93.6 to about 65.4 percent.17


Chemistry Of Toothpaste, Kayla Blanche Kirtley Apr 2022

Chemistry Of Toothpaste, Kayla Blanche Kirtley

Chemistry & Biochemistry Student Projects

The chemistry of toothpaste is explained, with a description of the chemical components and their mode of action in the role of toothpaste.


Clostridioides Difficile Spore Production In Response To Antibiotic And Immune Stress, Adenrele Oludiran, Erin B. Purcell Apr 2022

Clostridioides Difficile Spore Production In Response To Antibiotic And Immune Stress, Adenrele Oludiran, Erin B. Purcell

College of Sciences Posters

Clostridioides (Clostridium) difficile, an anaerobic, spore-forming Gram-positive pathogenic bacterium, is a major cause of hospital-acquired infections and can persist as surface-attached biofilms for protection from antibiotic and immune stress. C. difficile can form biofilms as a single species or with other anaerobic intestinal bacteria. The environmental signals that cause individual cells to secrete toxins, form biofilms, or develop into spores that can spread the infection to new patients are unknown. In these studies, we investigate bacterial responses to different stress. Antimicrobial host-defense peptides (HDPs) produced by animal immune systems are promising candidates to develop novel therapies for bacterial infection …


Towards Semiconductor Nanorods With Nickel/Iron Cocatalyst., Kehinde Ayorinde Apr 2022

Towards Semiconductor Nanorods With Nickel/Iron Cocatalyst., Kehinde Ayorinde

Masters Theses & Specialist Projects

The adverse effects associated with the utilization of fossil fuels has led to the need to provide an alternative cleaner energy. Photocatalytic hydrogen evolution reaction via water splitting provides a renewable pathway to generating energy. Our photocatalyst system includes a semiconductor component (CdSe/CdS core/shell nanorods) to capture light and an attached metal (cocatalyst) for the hydrogen evolution reaction. Platinum is an effective metal catalyst for this reaction due to strong proton binding energy that easily facilitates the reduction of water to produce hydrogen gas. However, due to the high cost of platinum, there is a need to find a less …


Synthetic, Photophysical, And Catalytic Studies Of Light-Harvesting Macrocyclic Complexes, Fox Bratcher Apr 2022

Synthetic, Photophysical, And Catalytic Studies Of Light-Harvesting Macrocyclic Complexes, Fox Bratcher

Masters Theses & Specialist Projects

Chromophores are an important class of compounds in Nature and industry, with several hundred thousand tons produced annually as dyes and pigments. Alone, these compounds absorb light unto themselves; however, several of these compounds can be combined to produce a beneficial cascading transfer of energy to a core chromophore.

In this study, photophysical properties of several covalent and axially borondipyrromethene (BODIPY)-conjugated complexes of porphyrin and salphen scaffolds have been evaluated in a series of emission and catalytic studies. In the porphyrin systems, a beneficial excited energy transfer (EET) from the BODIPY moieties to the porphyrin core was observed; however, only …


Covid-19 Pandemic Effects On The Environment, Ken Overway, Phillips Lane Apr 2022

Covid-19 Pandemic Effects On The Environment, Ken Overway, Phillips Lane

Chemistry Faculty Scholarship

The coronavirus disease of 2019 (COVID-19) pandemic has been a constant in everyone’s lives for almost the past three years now and has embedded itself into basically every part of global society and norms. The main areas where this is evident are in the major disruptions in the economic, social, and public health sectors of the world. There is one other area that has been affected by this prolonged pandemic in a multitude of ways, the environment. Our environment, both globally and regionally, has seen both positive and negative effects throughout the COVID-19 pandemic in a variety of different areas. …


Analysis Of The Headspace Gases Formed From The Fermentation Of Barley, Ken Overway, Cassie Taylor Apr 2022

Analysis Of The Headspace Gases Formed From The Fermentation Of Barley, Ken Overway, Cassie Taylor

Chemistry Faculty Scholarship

Volatile compounds are compounds that can exist in a gaseous state at room temperature. These compounds contribute to the aromas that are associated with mixtures. The analysis of these gases can be completed using a gas chromatograph to provide a sort of fingerprint identification. The analysis of the volatile compounds for barley fermentation samples was completed by collecting the gas above the fermenting solution, the headspace gas, and injecting this gas into the gas chromatograph. These fermentation samples showed predominantly the formation of carbon dioxide for a significant length of time before finally ethanol was detected. A subsequent of the …


Extraction & Purification Of Ppix Using Hplc & Fplc, Ken Overway, Grace Rilee Apr 2022

Extraction & Purification Of Ppix Using Hplc & Fplc, Ken Overway, Grace Rilee

Chemistry Faculty Scholarship

Porphyrins, an organic molecule, are a possible sensitizer for dye-sensitized solar cells (DSSC) because of their strong absorption in the visible spectrum. One naturally occurring porphyrin is protoporphyrin IX (PPIX), which can be found in brown eggshells. There are two reasons why PPIX is the ideal sensitizer. (1) The absorbance spectrum of PPIX can be modified by changing ring substituents, thus tuning the absorbance to the solar spectrum. (2) PPIX allows for direct attachment to the DSSC due to the carboxylic acid substituents on PPIX and the TiO2 of the DSSC. The HPLC was used to develop a chromatographic …


Cooperative Allosterism In Avidin And Streptavidin Upon Biotin Binding As Observed By Changes In Intrinsic Fluorescence, Alycia Murphy Apr 2022

Cooperative Allosterism In Avidin And Streptavidin Upon Biotin Binding As Observed By Changes In Intrinsic Fluorescence, Alycia Murphy

Celebration of Scholarship 2022

Avidin is a homotetrameric protein known for its high binding affinity and specificity for biotin which gives it great functionality in many biotech applications. Prior research on the bacterial analog, streptavidin found cooperative allosterism exhibited in the binding process. This research was aimed at investigating whether this same cooperative allosterism accompanies the binding of biotin to avidin. This work measured intrinsic tryptophan fluorescence as biotin was titrated into avidin. A blueshift in the wavelength of maximum fluorescence as well as quenching of the overall fluorescence intensity, similar to the streptavidin was observed. The saturation point for 335 nm emission (tryptophans …


A Damaged Reputation: Nuclear Depictions In Entertainment Media, Alexander Cannon Apr 2022

A Damaged Reputation: Nuclear Depictions In Entertainment Media, Alexander Cannon

Chemistry & Biochemistry Student Scholarship

This paper, originally written for Dr. Adamus Liotta in an honors chemistry class, explores the possibility of a significant influence over public common sense found in the depictions of entertainment media. Through careful analysis and interpretation of Godzilla, The Simpsons, Fallout, and Call of Duty, this paper finds a synergy throughout this diverse range of audience, medium and historical origin, which culminates in an effect much greater than the sum of its parts. This effect frames nuclear science, of any kind, in a hyperbolically catastrophic and horrific light, reinforcing an excessively cautious, pessimistic public perspective on nuclear technology …


The Analysis And Remediation Of Excess Fluoride In Drinking Water In Isle Of Wight County, Va, Kaleigh Beale Apr 2022

The Analysis And Remediation Of Excess Fluoride In Drinking Water In Isle Of Wight County, Va, Kaleigh Beale

Longwood Senior Theses

Excess fluoride in drinking water can cause fluorosis or brown and yellow staining of the enamel of teeth. In extreme cases, severe damage to teeth and bone structure can develop. In 1993, the World Health Organization set a limit of 1.5 ppm as acceptable for drinking water; however, in Isle of Wight County, Virginia, recent water quality reports detected levels of fluoride as high as 4 ppm. The purpose of this study was to investigate several detection and remediation methods of fluoride in drinking water. Detection methods included an ion selective electrode (ISE), dye-based colorimetric methods, and an at-home testing …


Synthesis And Evaluation Of Gallate Esters As Alternatives To Traditional Parabens, Marcia Reeves Apr 2022

Synthesis And Evaluation Of Gallate Esters As Alternatives To Traditional Parabens, Marcia Reeves

Longwood Senior Theses

Parabens are esters of p-hydroxybenzoates that are commonly found in everyday consumer products as well as pharmaceuticals. They are often used in commercial products to prevent bacterial growth as well as to provide extended shelf life, but they have been shown to activate estrogen receptors in vivo, a contributing factor in human breast cancer proliferation. Our lab has previously generated a multitude of paraben derivatives that do not exhibit estrogenic activity. Many of these derivatives may have other safety concerns, but gallate esters appear to have the least hazardous properties. The estrogenic, antimicrobial, and antioxidant properties of the gallate ester …


Quantification Of Silver Nanoparticle Interactions With Yeast Saccharomyces Cerevisiae Studied Using Single-Cell Icp-Ms, Lindsey Rasmussen, Honglan Shi, Wenyan Liu, Katie Shannon Apr 2022

Quantification Of Silver Nanoparticle Interactions With Yeast Saccharomyces Cerevisiae Studied Using Single-Cell Icp-Ms, Lindsey Rasmussen, Honglan Shi, Wenyan Liu, Katie Shannon

Chemistry Faculty Research & Creative Works

Silver nanoparticles (AgNPs) have been used in many fields due to their anticancer, antimicrobial, and antiviral potential. Single-cell ICP-MS (SC-ICP-MS) is an emerging technology that allows for the rapid characterization and quantification of a metal analyte across a cell population in a single analysis. In this study, a new rapid and sensitive SC-ICP-MS method was developed to quantitatively study the interactions of AgNPs with yeast Saccharomyces cerevisiae. The method can quantify the cell concentration, silver concentration per cell, and profile the nanoparticle distribution in a yeast cell population. AgNP dosing time, concentration, and AgNP size were quantitatively evaluated for their …


Unraveling Molecular Mechanisms Of Antibiotic Resistance Through Multiscale Simulations And Explainable Machine Learning, Zilin Song Apr 2022

Unraveling Molecular Mechanisms Of Antibiotic Resistance Through Multiscale Simulations And Explainable Machine Learning, Zilin Song

Chemistry Theses and Dissertations

Pathogen resistance to β-lactam antibiotics compromises effective treatments of superbug infections. One major source of β-lactam resistance is the bacterial production of β-lactamases, which could effectively hydrolyze β-lactam drugs. In this thesis, the hydrolysis of various β-lactam antibiotics by class A serine-based β-lactamases (ASβLs) were investigated using hybrid Quantum Mechanical / Molecular Mechanical (QM/MM) minimum energy pathway (MEP) calculations and explainable machine learning (ML) approaches. The TEM-1/benzylpenicillin acylation reaction with QM/MM chain-of-states reaction pathways was firstly revisited. I proposed two decomposition methods for energy contribution analysis based on perturbing ML regression models. Both methods were shown to be model implementation …


In Situ Recording Of Mars Soundscape, S. Maurice, B. Chide, N. Murdoch, R. D. Lorenz, D. Mimoun, R. C. Wiens, A. Stott, X. Jacob, T. Bertrand, F. Montmessin, N. L. Lanza, C. Alvarez-Llamas, Stanley M. Angel, M. Aung, J. Balaram, O. Beyssac, A. Cousin, G. Delory, O. Forni, T. Fouchet, Et. Al. Apr 2022

In Situ Recording Of Mars Soundscape, S. Maurice, B. Chide, N. Murdoch, R. D. Lorenz, D. Mimoun, R. C. Wiens, A. Stott, X. Jacob, T. Bertrand, F. Montmessin, N. L. Lanza, C. Alvarez-Llamas, Stanley M. Angel, M. Aung, J. Balaram, O. Beyssac, A. Cousin, G. Delory, O. Forni, T. Fouchet, Et. Al.

Faculty Publications

Before the Perseverance rover landing, the acoustic environment of Mars was unknown. Models predicted that: (1) atmospheric turbulence changes at centimetre scales or smaller at the point where molecular viscosity converts kinetic energy into heat1, (2) the speed of sound varies at the surface with frequency2,3 and (3) high-frequency waves are strongly attenuated with distance in CO2 (refs. 2,3,4). However, theoretical models were uncertain because of a lack of experimental data at low pressure and the difficulty to characterize turbulence or attenuation in a closed environment. Here, using Perseverance …


Faith Jacobsen - Sabbatical Spring 2022, Faith Jacobsen Apr 2022

Faith Jacobsen - Sabbatical Spring 2022, Faith Jacobsen

Sabbatical Projects

My sabbatical had two main parts:

1. Analysis of data collected the previous semesters and writing up a research paper about student learning gains from making video quizzes of lab techniques. This work was published in the Journal of Chemical Education in Spring 2023.

https://pubs.acs.org/doi/10.1021/acs.jchemed.2c00867

2. Creation of an online platform to learn organic spectroscopy using the open source software Twinery.


Microwave-Assisted Synthesis Of Quinoxaline Derivatives, Eric Horsting Apr 2022

Microwave-Assisted Synthesis Of Quinoxaline Derivatives, Eric Horsting

Honors Theses

Quinoxaline and its derivatives have been studied extensively for their relevant biological activity and transition metal selectivity. These compounds are commonly used for their antimicrobial, antifungal, antiparasitic activity, and relevance in the treatment of metabolic diseases [6]. More recently, quinoxaline’s ability to inhibit gram-positive bacterial growth has been found especially in oxygen- containing compounds, yielding promising candidates to prevent cancerous tumor growth [5]. The breadth of quinoxaline makes it a valuable tool within the research community However, its synthesis requires complex solvents, extended reaction times, and often produces a low yield. By using a microwave-assisted synthesis, this novel methodology offers …


Studies Toward Provenance Determination For Indigo Dyes, Erin Kibby Apr 2022

Studies Toward Provenance Determination For Indigo Dyes, Erin Kibby

Undergraduate Honors Thesis Projects

Species of indigo-producing plants have been used to color textiles for thousands of years all over the globe. Natural indigo-producing species have historically been harvested in regions of Asia, North Africa, and North and South America. This study is an exploration of methods that can be used to determine the provenance (origin) of the indigo dye in a textile through the extraction and isolation of indigoids, flavonoids, and other compounds from the natural dyestuff. There is no accepted method of extracting flavonoids from indigo-dyed textiles specifically, and there is little investigation of the regionally different species. If a method is …


Sustainable Polymers: Upcycling Poly(Vinyl Chloride) And Mimicking Low Density Polyethylene, Ian Baxter Apr 2022

Sustainable Polymers: Upcycling Poly(Vinyl Chloride) And Mimicking Low Density Polyethylene, Ian Baxter

Theses and Dissertations

In this research, increasing the sustainability of polymers was investigated through two main methods. The upcycling of poly(vinyl chloride) and the creation of polymer mimics to create degradable low-density polyethylene. In the first chapter, an overview of the sustainability issues of polymers is presented and approaches are described on how their sustainability may be increased through the upcycling of polymers or the synthesis of degradable polymers that mimic the properties of petrol-based polymers.

Chapter 2 contains the progress on the upcycling of PVC using high oleic soybean oil. Soybean oil can soften PVC making it less brittle than pure PVC. …


Photophysics And Electronic Properties Of Photochromic Metal-Organic Frameworks, Corey R. Martin Apr 2022

Photophysics And Electronic Properties Of Photochromic Metal-Organic Frameworks, Corey R. Martin

Theses and Dissertations

Modulation of materials properties through light-based illumination has the capability to expand the technology sector due to stimuli-responsive dynamic behavior that cannot be achieved in traditional materials. For example, reversibly tuning photophysical profiles of such materials allows for switching between discrete states that is a key aspect for the developing logic gates, spatially- and temporally-resolved sensors, and on-demand drug delivery systems. My efforts have focused on employment of metal-organic frameworks (MOFs) as a versatile platform for the material development which contain photochromic moieties allowing for tailoring their electronic properties. Our group has expanded this direction to include heterometallic and actinide-containing …


Understanding The Hydrolytic Activity Of Papiliotrema Laurentii On Polyester Polyurethane Coatings, Ariana L. Santos Apr 2022

Understanding The Hydrolytic Activity Of Papiliotrema Laurentii On Polyester Polyurethane Coatings, Ariana L. Santos

Honors Theses

Though plastic polymers such as polyester polyurethanes have many applications from electronics to aircraft coatings, their resistance to natural degradation presents an environmental concern. Therefore, elucidating the mechanism of degradation from microorganisms that were discovered breaking down the coating of a cargo aircraft may offer insights into a method of bioremediation. To explore this, the fungus Papiliotrema laurentii (one microorganism isolated from the consortium) was cultured in several different media types at different pH levels in order to understand how it adjusts its protein secretion patterns to environmental changes. 2D gel electrophoresis, isoelectric focusing (IEF) and a variety of gel …


College Of Natural Sciences Newsletter, March & April 2022, College Of Natural Sciences Apr 2022

College Of Natural Sciences Newsletter, March & April 2022, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 3, Issue 3

Page 1 Dean's Message
Page 2-3 Awards and Recognition
Page 4 2022 URSCAD - CNS Snaps
Page 5 Geography Convention Recap
Page 6 Attention Students!
Page 7-8 Media Coverage of CNS
Page 9 Spring Break Outreach, Adopt the Pantry,
Page 10 Discovery on Tap Event
Page 11 CNS Students Visit State Capital
Page 12 Celebrating 50 Years of Sally
Page 13 Open PRAIRIE Data
Page 14 Grants Awarded and Bio-Micro Day of Scholars
Page 15 -17 2022 Geography Convention Snaps
Page 18 Sally Krueger's 50th Work Anniversary


1st Place Contest Entry: Designing Hollow Nanogels For Drug Delivery Applications, Mo Hijazi Apr 2022

1st Place Contest Entry: Designing Hollow Nanogels For Drug Delivery Applications, Mo Hijazi

Kevin and Tam Ross Undergraduate Research Prize

This is Mo Hijazi's submission for the 2022 Kevin and Tam Ross Undergraduate Research Prize, which won first place. It contains their essay on using library resources, their bibliography, and a summary of their research project on hollow-core nanogels.

Mo is a second-year student at Chapman University, majoring in Biological Sciences. Their faculty mentor is Dr. Molla Islam.


Synthesis And Characterization Of Enantioenriched Deuterated And Fluorinated Small Molecules, Mitchell D. Mills Apr 2022

Synthesis And Characterization Of Enantioenriched Deuterated And Fluorinated Small Molecules, Mitchell D. Mills

Master's Theses (2009 -)

The development of novel deuterated and fluorinated bioisosteres has significantly impacted the pharmaceutical and agricultural industry and created a growing demand for new synthetic methodology. Both deuterated and fluorinated small molecules exist at the forefront of drug discovery due to their unique ability to attenuate the pharmacokinetic properties of new and currently existing drugs. Selective, high-throughput methods for deuteration and fluorination are scarce in the literature, especially methods that introduce D or F atoms asymmetrically. Benzylic CH bonds are oftentimes key sites for enzymatic manipulation in metabolic processes, alteration of CH bonds to CD or CF bonds at the benzylic …


Intrinsic Photodynamic Study On Photocatalytic Materials, Wenhui Hu Apr 2022

Intrinsic Photodynamic Study On Photocatalytic Materials, Wenhui Hu

Dissertations (1934 -)

To relieve the global energy crisis and environmental pollution caused by the combustion of traditional fossil fuels, developing an environmental-friendly renewable energy to replace fossil fuel is urgent. Among the possible energy sources, solar energy has attracted numerous attentions because of the abundant storage. However, it is challenging to efficiently utilize and store solar energy. One attractive strategy to address this challenge is to convert solar energy to fuel through artificial photosynthesis (e.g. photocatalytic water splitting to generate H2). A technologically significant solar-driven water splitting system requires an efficient photocatalytic system that can not only effectively harvest light but also …