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

Chemistry Commons™

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

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 7951 - 7980 of 33209

Full-Text Articles in Chemistry

Synthesis, Cytotoxicity And Anti-Inflammatory Activity Of Piperine Derivatives, Dina Nur Shinta Jan 2021

Synthesis, Cytotoxicity And Anti-Inflammatory Activity Of Piperine Derivatives, Dina Nur Shinta

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cancer is a significant leading cause of mortality worldwide which has been struggled in the clinical over the years. Parallelly, chronic inflammation becomes one of the risk factors to cause cancer. In searching for new potential anti-cancer and anti-inflammatory agents, an amide, ester, and dimer series of piperine derivatives were synthesized and screened for their anti-cancer and anti-inflammatory activities. Piperine (1) was isolated from fruits of Piper longum L. and hydrolyzed under reflux conditions to obtain piperic acid (2) as a starting material for the synthesis. The conversion of piperic acid to an amide series (3a-j) was involving an azabenzotriazole …


Ligand Effects On Electronic, Magnetic, And Catalytic Properties Of Clusters And Cluster Assemblies, Dinesh Bista 9288522 Jan 2021

Ligand Effects On Electronic, Magnetic, And Catalytic Properties Of Clusters And Cluster Assemblies, Dinesh Bista 9288522

Theses and Dissertations

Ligands commonly protect metallic clusters against reacting with outside reactants. However, ligands can also be used to control the redox properties enabling the formation of super donors/acceptors that can donate/accept multiple electrons. This thesis focuses on how the ligands can be used to control the electronic and magnetic features of clusters and ligand stabilized cluster-based assemblies, leading to nano pn junctions with directed transport, the possibility of light-harvesting, and catalysts for cross-coupling reactions. The thesis addresses three distinct classes of clusters and their applications. The first class of cluster “metal chalcogen clusters” is the central idea of the thesis focused …


Nebulizer-Based Systems To Improve Pharmaceutical Aerosol Delivery To The Lungs, Benjamin M. Spence Jan 2021

Nebulizer-Based Systems To Improve Pharmaceutical Aerosol Delivery To The Lungs, Benjamin M. Spence

Theses and Dissertations

Combining vibrating mesh nebulizers with additional new technologies leads to substantial improvements in pharmaceutical aerosol delivery to the lungs across therapeutic administration methods. In this dissertation, streamlined components, aerosol administration synchronization, and/or Excipient Enhanced Growth (EEG) technologies were utilized to develop and test several novel devices and aerosol delivery systems. The first focus of this work was to improve the poor delivery efficiency, e.g., 3.6% of nominal dose (Dugernier et al. 2017), of aerosolized medication administration to adult human subjects concurrent with high flow nasal cannula (HFNC) therapy, a form of continuous-flow non-invasive ventilation (NIV). The developed Low-Volume Mixer-Heater (LVMH) …


Fabrication Of Metal-Silicon Nanostructures By Reactive Laser Ablation In Liquid, Eric J. Broadhead Jan 2021

Fabrication Of Metal-Silicon Nanostructures By Reactive Laser Ablation In Liquid, Eric J. Broadhead

Theses and Dissertations

Metal-silicon nanostructures are a growing area of research due to their applications in multiple fields such as biosensing and catalysis. In addition, silicon can provide strong support effects to metal nanoparticles while being more cost effective than traditionally used supports, like titania. Traditional wet-chemical methods are capable of synthesizing metal-silicon nanostructures with a variety of composition and nanoparticle shapes, but they often require high temperatures, toxic solvents, strong reducing agents, or need capping agents added to stabilize the nanoparticles. Laser processing is an emerging technique capable of synthesizing metal-silicon composite surfaces that offers a faster, simpler, and greener synthesis route …


The Rational Synthesis Of Lanthanum Manganite Nanomaterials For Magnetic Refrigeration Applications, Caitlin Hunt Jan 2021

The Rational Synthesis Of Lanthanum Manganite Nanomaterials For Magnetic Refrigeration Applications, Caitlin Hunt

Theses and Dissertations

Refrigeration systems for the cooling of commercial and residential buildings are a major drain on energy resources and source of greenhouse gas emissions. Magnetic refrigeration, which employs the magnetocaloric effect, has the potential to mitigate the energy drain and greenhouse gas emissions for air conditioning. In order to commercialize magnetic refrigerators, a material with a high magnetic entropy change, ΔS, near room temperature which is simple and inexpensive to create is needed.1 Current options for this solid refrigerant are either expensive, difficult to synthesize, or have a ΔS or Tc (the Curie Temperature, where ΔS is maximized) below …


Strategies For Resolution Enhancement In Liquid Chromatography, Shelby Lynn Weatherbee Jan 2021

Strategies For Resolution Enhancement In Liquid Chromatography, Shelby Lynn Weatherbee

Theses and Dissertations

Recent research in liquid chromatography (LC) has led to the development of new methodologies to further improve sample analysis. Non-uniform stationary phases are one such area that focuses on developments in selectivity and efficiency of stationary phases. Within this subset of stationary phases are two major focuses: two-dimensional liquid chromatography (2D-LC) and continuous stationary phase gradients that are the basis of this work.

In this work, LC simulation software was adapted to simulate chromatograms based on experimental and modeled injection profiles. This was done by measuring the injection profiles from a 2D-LC active solvent modulation valve using a variety of …


Unraveling A Trifecta Of Weak Non-Covalent Interactions: The Dissociation Energy Of The Anisole-Ammonia 1:1 Complex, John L. Loman, James T. Makuvaza, Damian L. Kokkin, Scott A. Reid Jan 2021

Unraveling A Trifecta Of Weak Non-Covalent Interactions: The Dissociation Energy Of The Anisole-Ammonia 1:1 Complex, John L. Loman, James T. Makuvaza, Damian L. Kokkin, Scott A. Reid

Chemistry Faculty Research and Publications

The anisole-ammonia 1:1 complex is a challenge for both experiment and theory. Early studies supported a non-planar structure, involving a trifecta of weak non-covalent interactions: N-H/O, N-H/π, and C-H/N. The calculated structure and binding energy of the complex proved remarkably sensitive to the level of theory employed. Here, we report the first experimental measurement of the ground state dissociation energy of the complex, and derive an excited (S1) state dissociation energy that is in excellent agreement with the cutoff observed in the experimental excitation spectrum. Results are compared with previous predictions and new calculations based on benchmarked Density …


Pine River Pond 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft Jan 2021

Pine River Pond 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft

UNH Cooperative Extension

No abstract provided.


Development Of Tripodal And Bipodal Ligand Frameworks And First-Row Transition Metal Reagents For Selective C-N Bond Construction Methodologies, Anshika Kalra Jan 2021

Development Of Tripodal And Bipodal Ligand Frameworks And First-Row Transition Metal Reagents For Selective C-N Bond Construction Methodologies, Anshika Kalra

Doctoral Dissertations

"We present a family of anionic Mn(II) reagents supported by trisphenylamido- amlne frameworks that offer guidance with regards to ligand selection for developing C—N bond construction methodologies (extensively used in the synthesis of petrochemicals, household chemicals) through nitrene- transfer chemistry. We subsequently extend the study to include the corresponding Fe(II), Co(II), and Ni(II) reagents, to gain insights in their comparative reactivity/selectivity patterns. Attenuated levels of electrophilicity of anionic complexes proved to be more suitable for discriminating aromatic from aliphatic olefins for aziridination purposes, especially for Mn(II) complexes. However, in the case of Co(II) reagents, we observe that additional stereoelectronic parameters …


Development Of Synthetic Coal Char Simulant For Microwave Conversion Studies: A Computationally-Driven Approach, Kevin A. Hager Jan 2021

Development Of Synthetic Coal Char Simulant For Microwave Conversion Studies: A Computationally-Driven Approach, Kevin A. Hager

Graduate Theses, Dissertations, and Problem Reports (ETD)

Recent experimental demonstration of new reaction windows for coal char/methane reactions that are less energy-intensive, provides innovation for modular reactors. However, the correlation of the exact mechanism for the enhancement of these reaction windows is not certain. This study investigates the simplification of these experimental studies by developing a well-characterized coal char simulant. The approach involves using a computational approach to screen macroscopic composition to replicate the dielectric and compositional response of actual char. This study is focused on PRB coal char. A discrete element method (DEM) technique was used to simulate the packing of coal chars to give the …


On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Fall 2020, Gary A. Bishop Jan 2021

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Fall 2020, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Advanced Analytical Techniques For The Analysis Of Therapeutics Of Toxic Inhalation Agents And Pharmacokinetic Investigation, Subrata Bhadra Jan 2021

Advanced Analytical Techniques For The Analysis Of Therapeutics Of Toxic Inhalation Agents And Pharmacokinetic Investigation, Subrata Bhadra

Electronic Theses and Dissertations

Toxic inhalation agents (TIAs), (i.e., cyanide (CN) and reduced sulfur compounds (RSCs)), including hydrogen sulfide (H2S) and methanethiol (MT)) are extremely poisonous upon exposure. Many TIAs act by inhibiting mitochondrial cytochrome c oxidase, resulting in cellular hypoxia, cytotoxic anoxia, apnea, respiratory failure, cardiovascular collapse, seizure and potentially death. CN is generated in structural fires and cigarette smoke as well as in mining, electroplating and polymer processing, whereas H2S and MT are found in petroleum, oil and natural gas, waste treatment facilities and decaying organic matter. All are common occupational gas exposure hazards in chemical industries and for first responders, including …


Bow Lake (Station 3 - Bennett) 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft Jan 2021

Bow Lake (Station 3 - Bennett) 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft

UNH Cooperative Extension

A Water Quality Highlight Report by UNH CE Lakes Lay Monitoring Program for Bow Lake, Station 3 Bennett (Barrington and Northwood, NH) for 2021.


Baboosic Lake 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft Jan 2021

Baboosic Lake 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft

UNH Cooperative Extension

A Water Quality Highlight Report by UNH CE Lakes Lay Monitoring Program for Baboosic Lake (Amherst and Merrimack, NH) for 2021.


Lovell Lake 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft Jan 2021

Lovell Lake 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft

UNH Cooperative Extension

A Water Quality Highlight Report by UNH CE Lakes Lay Monitoring Program for Lovell Lake (Sanbornville, NH) for sampling efforts in 2021.


Lake Ivanhoe 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft Jan 2021

Lake Ivanhoe 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft

UNH Cooperative Extension

A Water Quality Highlight Report by UNH CE Lakes Lay Monitoring Program for Lake Ivanhoe (Wakefield, NH) for sampling efforts in 2021.


Belleau Lake 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft Jan 2021

Belleau Lake 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft

UNH Cooperative Extension

A Water Quality Highlight Report by UNH CE Lakes Lay Monitoring Program for Belleau Lake in Wakefield, NH for 2021.


Balch Pond 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft Jan 2021

Balch Pond 2021 Water Quality Highlight Report, Amanda Mcquaid, Robert Craycraft

UNH Cooperative Extension

A Water Quality Highlight Report by UNH CE Lakes Lay Monitoring Program for Balch Pond (Wakefield, NH; Acton and Newfield, ME) for sampling efforts up to 2021.


Investigation Of Emissions And Chemistry Of Formic Acid And Acetic Acid In Wildfire Smoke, Catherine Elizabeth Wielgasz Jan 2021

Investigation Of Emissions And Chemistry Of Formic Acid And Acetic Acid In Wildfire Smoke, Catherine Elizabeth Wielgasz

Graduate Student Theses, Dissertations, & Professional Papers

Formic acid (HCOOH) and acetic acid (CH3COOH) are two of the most ubiquitous organic acids in the atmosphere. Chemical transport models consistently underestimate HCOOH and CH3COOH concentrations in environments including fire smoke, implying our incomplete understanding of their global budget. Emissions and secondary production of HCOOH and CH3COOH within complex mixtures in fire smoke is uncertain.

I used measurements from the NSF/NCAR C-130 aircraft during the Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE-CAN) campaign to investigate emissions and photochemical production of HCOOH and CH3COOH from smoke plumes. First, …


Development Of A Novel In-Situ Chemical Sampler For Aquatic Systems, Alec W. Johnson Jan 2021

Development Of A Novel In-Situ Chemical Sampler For Aquatic Systems, Alec W. Johnson

Graduate Student Theses, Dissertations, & Professional Papers

There has been a long-standing need to study Dissolved Organic Carbon (DOC) within aquatic systems. DOC is an important water quality parameter that provides insights into ecological and carbon cycle processes in aquatic systems. DOC is not easily studied due to traditional, labor-intensive sampling methods. Often, optical (e.g. fluorescence) proxy estimations for DOC are used instead of directly sampling for DOC. Using either low frequency measurements or proxy estimations for DOC can lead to inadequate understanding of the natural processes that control DOC in aquatic systems.

This thesis outlines a in-situ sampler that will be capable of collecting, preserving, and …


Absorbent Household Materials For The Collection Of Ignitable Liquid Residues From Surfaces Of Varying Porosity, Jessica Carlotti Jan 2021

Absorbent Household Materials For The Collection Of Ignitable Liquid Residues From Surfaces Of Varying Porosity, Jessica Carlotti

Online Theses and Dissertations

Ignitable liquids (ILs) are used as accelerants to burn items at a faster rate and the presence of an IL indicates that arson has occurred. Upon arrival to an arson scene, fire investigators access the scene and collect substrates containing ILs. The substrates, such as concrete and wood, are removed from the scene by methods that are time consuming, and require heavy machinery and tools. The evidence is transported in air-tight containers to the laboratory where analysts identify the chemical classification of the IL using gas chromatography mass spectrometry (GC-MS). In this work, readily available absorbent household materials such as …


In Depth Characterisation Of The Biomolecular Coronas Of Polymer Coated Inorganic Nanoparticles With Differential Centrifugal Sedimentation, André Perez-Potti, Hender Lopez, Beatriz Pelaz, Abuelmagd Abdelmonem, Mahmoud G. Soliman, Ingmar Schoen, Philip M. Kelly, Kenneth A. Dawson, Wolfgang J. Parak, Zeljka Krpetic, Marco P. Monopoli Jan 2021

In Depth Characterisation Of The Biomolecular Coronas Of Polymer Coated Inorganic Nanoparticles With Differential Centrifugal Sedimentation, André Perez-Potti, Hender Lopez, Beatriz Pelaz, Abuelmagd Abdelmonem, Mahmoud G. Soliman, Ingmar Schoen, Philip M. Kelly, Kenneth A. Dawson, Wolfgang J. Parak, Zeljka Krpetic, Marco P. Monopoli

Articles

Advances in nanofabrication methods have enabled the tailoring of new strategies towards the controlled production of nanoparticles with attractive applications in healthcare. In many cases, their characterisation remains a big challenge, particularly for small-sized functional nanoparticles of 5 nm diameter or smaller, where current particle sizing techniques struggle to provide the required sensitivity and accuracy. There is a clear need for the development of new reliable characterisation approaches for the physico-chemical characterisation of nanoparticles with significant accuracy, particularly for the analysis of the particles in the presence of complex biological fluids. Herein, we show that the Differential Centrifugal Sedimentation can …


Huntingtin Aggregation At Interfaces Associated With Membranes And Organelles, Adewale Vincent Adegbuyiro Jan 2021

Huntingtin Aggregation At Interfaces Associated With Membranes And Organelles, Adewale Vincent Adegbuyiro

Graduate Theses, Dissertations, and Problem Reports (ETD)

Huntington’s Disease (HD) is a genetic neurodegenerative disease caused by the expansion of polyglutamine (polyQ) domain within the first exon (exon1) of the huntingtin (htt) protein. Due to this mutation within the polyQ domain, htt aggregates into various toxic species such as oligomers, fibrils, and other amorphous aggregates. While the aggregation of htt strongly correlates with polyQ length, other factors, e.g. interaction with membranes or organelles and posttranslational modifications (PTMs), modulate aggregation. The first 17 N-terminal amino acids (Nt17) that precede the polyQ in htt-exon1 enhances aggregation and facilitated binding of htt to membranous organelles, promoting morphological changes and disfunction. …


Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright Jan 2021

Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright

Theses

Anomalously elevated arsenic concentrations occur at an abandoned artisanal mine site in an open space recreational park in urban San Diego County, California. Although mining at the site ceased 100 years ago little to no remediation efforts took place leaving shafts, adits, waste piles and derelict infrastructure accessible by inquisitive hikers and adventurers frequenting Black Mountain Open Space Park. This study evaluates the geochemical mechanisms of As transport downgradient from the mine and examines the contribution of both climate and urbanization on the restriction of As mobility. Sediment As concentrations reach 2,320 mg/kg (483 times background crustal concentrations; n=73) along …


Understanding The Relationship Between Local Environmental Changes And The Function Of The Ph Low Insertion Peptide, Violetta Burns Casamayor Jan 2021

Understanding The Relationship Between Local Environmental Changes And The Function Of The Ph Low Insertion Peptide, Violetta Burns Casamayor

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cancer is the second leading cause of death in the US with over 1.7 million new cases each year. Current cancer treatments tend to also target healthy tissues due to similarities with cancerous ones, resulting in acute side effects. Early detection is the best approach towards defeating cancer, however, modern imaging techniques require sizeable samples, often implying a late stage in the disease. One common attribute of tumors is their acidic microenvironment, which can be taken advantage of.

The pH Low Insertion Peptide (pHLIP) is a membrane-active peptide that can take advantage of the acidic microenvironment surrounding cancer cells. pHLIP …


Enhancing Negative-Ion Native Mass Spectrometry With Field-Assisted Capillary Vibrating Sharp-Edge Spray Ionization (Cvssi), Kushani Udeshika Attanayake Jan 2021

Enhancing Negative-Ion Native Mass Spectrometry With Field-Assisted Capillary Vibrating Sharp-Edge Spray Ionization (Cvssi), Kushani Udeshika Attanayake

Graduate Theses, Dissertations, and Problem Reports (ETD)

Although the birth of native mass spectrometry (native MS) occurred only several years after the development of electrospray ionization (ESI), it is yet considered an emerging technique for MS-based studies. This stems in part from challenges associated with efficient ionization of biopolymers. Although steady gains in ion production for native structure characterization have been secured primarily with the use of nanoelectrospray ionization (nESI), under negative polarity, the ionization efficiency can be extensively reduced due to an effect called “corona discharge”. The corona discharge occurs at the tip of ESI emitters because of free electron acceleration in the high-field region produced …


Improving Characterization Of Small Molecules Using Enhanced Molecular Reaction And Ionization Techniques, Sandra N. Majuta Jan 2021

Improving Characterization Of Small Molecules Using Enhanced Molecular Reaction And Ionization Techniques, Sandra N. Majuta

Graduate Theses, Dissertations, and Problem Reports (ETD)

Metabolomics is an emerging “omics” field, which is comprised of the study of small molecule metabolites in biological systems. It can be argued that the abundances of metabolites within biological samples, such as tissue and plasma, are indicative of various physiological states. Thus, metabolomics analysis has the potential in the clinical scientific field to be an effective tool for early disease diagnosis as well as for proposing and monitoring new treatments for diseases. However, full characterization of the metabolome complement is often hampered by the wide diversity of metabolites, which also exhibit an extremely large concentration range in biological samples. …


Photochemical Motion Control Of Belousov-Zhabotinsky Droplets And Turbulence-Like Patterns In The Aluminum Hydroxide Precipitation System, Syed Jazli Syed Jamaluddin Jan 2021

Photochemical Motion Control Of Belousov-Zhabotinsky Droplets And Turbulence-Like Patterns In The Aluminum Hydroxide Precipitation System, Syed Jazli Syed Jamaluddin

Graduate Theses, Dissertations, and Problem Reports (ETD)

A Belousov-Zhabotinsky (BZ) droplet that is immersed in an oil-phase can self-propel due to a surface tension gradient that exists on the droplet surface. The surface tension gradient is created as a result of the reactions that occur within and on the surface of the BZ droplet. By affecting the rates of these reactions, the BZ droplet direction can be controlled. In our experiments, we tune the reactions that occur within and on the BZ droplet surface by imposing a light intensity gradient on the droplet. We analyzed the BZ droplet motion and demonstrated that we can control the droplet …


Analysis Of Cell Signaling Perturbations In Response To Chronic Localized Infections, Amber Nicole Prince Jan 2021

Analysis Of Cell Signaling Perturbations In Response To Chronic Localized Infections, Amber Nicole Prince

Graduate Theses, Dissertations, and Problem Reports (ETD)

The tissue-level response to pathogens involves an intricate series of signal transduction events, influenced by immune and healing mediators that alert the host to danger and eliminate the infection. Disruptions to normal signaling events can compromise the host’s ability to respond and lead to the development of chronic infections that cannot be resolved without clinical intervention. Prolonged inflammation due to chronic infection can damage tissues and compromise healing processes, thus, the interactions of immune and healing mediators in signaling cascades are intimately linked to tissue health outcomes. Studying signaling networks relevant to these responses provided a more thorough understanding of …


Gas Phase Reactions Of Cyclopentadiene With Ch And Oh Radicals, Kacee Lynn Caster Jan 2021

Gas Phase Reactions Of Cyclopentadiene With Ch And Oh Radicals, Kacee Lynn Caster

Graduate Theses, Dissertations, and Problem Reports (ETD)

The formation of polycyclic aromatic hydrocarbons (PAHs) and carbon-based nanoparticles in combustion environments is driven by the pyrolysis and oxidation of abundant fuel molecules. The subsequent growth of these pyrolytic byproducts is then propagated by reactions with small free radical species like OH, CH, O atoms, and C2H. Cyclopentadiene (C5H6) is a significant five-member combustion intermediate that has been detected in many high temperature reactions, such as in the pyrolysis of jet fuels like JP-10. Experimental and theoretical investigations in the reactions of cyclopentadiene with these small free radical species are necessary towards understanding …