Development Of Analytical Methods For Toxic Inhaled Hazards (Tih) And Their Metabolites,
2020
South Dakota State University
Development Of Analytical Methods For Toxic Inhaled Hazards (Tih) And Their Metabolites, Obed Adu Gyamfi
Electronic Theses and Dissertations
Toxic inhalation hazards (TIHs), such as methyl isocyanate (MIC) and hydrogen cyanide (HCN), are noxious gases and vapors that are harmful, and often deadly, to humans. However, because of their low cost and high reactivity, they are extensively used for industrial productions, creating risk of exposure for both industrial workers (e.g., occupational exposure) and civilians (e.g., accidental release during transport). The illicit use of TIHs, including as terrorist agents, is also concerning. Considering the rapid toxicity of TIHs and the danger they pose to both human and animal lives, there is a critical need to develop of analytical methods for …
Design, Construction, And Characterization Of A Combined Mini-Co₂/Voc Sensor And Gas Chromatograph For Field Research,
2020
University of Central Florida
Design, Construction, And Characterization Of A Combined Mini-Co₂/Voc Sensor And Gas Chromatograph For Field Research, Rishi Basdeo, Michael Hampton
Digital Repository: Showcase of Undergraduate Research Excellence
No abstract provided.
An Ammonia Sensor Using An Unadorned Bromocresol Layer,
2020
Technological University Dublin
An Ammonia Sensor Using An Unadorned Bromocresol Layer, John Cassidy, Caoimhe Ní Néill, Merve Akdağ, Tony Betts
Articles
Bromocresol Purple,(BCP) cast onto an acetate sheet, was used to sense ammonia. This simple layer responded reversibly to a low concentration ( 15 ppm) of ammonia in the presence of water vapour. The BCP solution was spincoated on an acetate sheet from a solution in dichloromethane. This layer was exposed to nitrogen and NH3/H2O vapour in quick succession. The colour change occurred from yellow to purple rapidly in the solid state. The λmax for the neutral ( acid) form of the BCP was found to be 435 nm and the λmax for the dianion ( base form) of the BCP …
Gc-Ms Analysis Of Synthesized Biodiesel,
2020
State University of New York College at Buffalo - Buffalo State College
Gc-Ms Analysis Of Synthesized Biodiesel, Courtney R. Whetstine
Forensic Science Master's Projects
Biodiesel is an alternative energy resource that can replenish depleting natural petroleum storage. Synthesis of biodiesel is cost-efficient as it can be chemically converted from renewable wastes, such as vegetable oil or animal fat. These fuels are also biodegradable and the exhaust emissions from biodiesel are non-toxic and environmentally-friendly. Biodiesel is a stable fuel that performs reliably in all diesel engines. Biodiesel is also easy to synthesize, safe to handle, and works with diesel fuel storage and pumping systems. The United States has an abundance of vegetable oils that have not been widely used to our advantage. Additionally, fast-food restaurants …
A Validated Uplc-Ms/Ms Method For The Determination Of Aliphatic And Aromatic Isocyanate Exposure In Human Urine,
2020
Chemistry Department, Université du Québec à Montréal; Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST)
A Validated Uplc-Ms/Ms Method For The Determination Of Aliphatic And Aromatic Isocyanate Exposure In Human Urine, Maggy Lépine, Lekha Sleno, Jacques Lesage, Sébastien Gagné
Études primaires
4,4′-Methylenediphenyldiisocyanate (MDI), toluenediisocyanate (2,4-TDI and 2,6-TDI), and 1,6′-hexamethylenediisocyanate (HDI) are all commonly used in the production of polyurethane-containing materials in different application areas. Workers exposed occupationally to these compounds may develop sensitization with the potential to lead to asthma. Isocyanates are metabolized in vivo by conjugation to macromolecules and/or by acetylation prior to being eliminated in urine. The hydrolysis of urine samples releases free amine compounds from these metabolites as biomarkers of exposure, specific to each parent isocyanate: 4,4′-methylenedianiline (MDA), toluenediamine (2,4-TDA and 2,6-TDA), and hexamethylenediamine (HDA). To address the need for a validated method that could be used for …
Method Development For The Analysis Of Fatty Acids In Adipose Tissue Using Stir Bar Sorptive Extraction Coupled With Gas Chromatography-Mass Spectrometry,
2020
University of Texas at El Paso
Method Development For The Analysis Of Fatty Acids In Adipose Tissue Using Stir Bar Sorptive Extraction Coupled With Gas Chromatography-Mass Spectrometry, Angela Marisol Encerrado Manriquez
Open Access Theses & Dissertations
The project was aimed to develop an easy and sensitive analytical tool to study the role of fatty acids (FAs) profile in periprostatic adipose tissue (PPAT) and prostate cancer (PCa). PCa is the second leading cause of cancer-related death among American men. Although obesity has been mostly ruled out by many researchers as a risk factor for developing PCa, it has shown to be associated with PCa metastasis and progression. Periprostatic adipose tissue, which was present on 48% of prostatic surfaces, has been reported to act as energy sources for facilitating a positive microenvironment for PCa tumor progression. To understand …
Development Of A Method For The Detection And Quantification Of Various Benzodiazepines And Z-Drugs In Human Blood And Qualitative Identification In Urine Samples Using Liquid Chromatography Mass Spectrometry (Lc-Ms/Ms),
2020
The University of Akron
Development Of A Method For The Detection And Quantification Of Various Benzodiazepines And Z-Drugs In Human Blood And Qualitative Identification In Urine Samples Using Liquid Chromatography Mass Spectrometry (Lc-Ms/Ms), Haley Michel
Williams Honors College, Honors Research Projects
This method developed in the toxicology department at the Cuyahoga County Medical Examiner’s Office (CCMEO) detects 40 benzodiazepines and metabolites along with several z-drugs in blood and urine by liquid chromatography tandem mass spectrometry. A sample amount of 0.5 mL was used to detect analytes in postmortem drug facilitated sexual assault and impaired driving cases. Twenty-nine analytes met criteria for quantification while the remaining 14 were used as qualitative indicators. Bias and precision results for quality controls met criteria, staying within ±15% except for clonazolam and etizolam which were within ±20%. Quantitative reporting criteria which included dilution integrity was met …
Resolving The Puzzle Of Single-Atom Silver Dispersion On Nanosized Γ-Al2O3 Surface For High Catalytic Performance,
2020
Chinese Academy of Sciences, Beijing
Resolving The Puzzle Of Single-Atom Silver Dispersion On Nanosized Γ-Al2O3 Surface For High Catalytic Performance, Fei Wang, Jinzhu Ma, Shaohui Xin, Qiang Wang, Jun Xu, Changbin Zhang, Hong He, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
Ag/γ-Al2O3 is widely used for catalyzing various reactions, and its performance depends on the valence state, morphology and dispersion of Ag species. However, detailed anchoring mechanism of Ag species on γ-Al2O3 remains largely unknown. Herein, we reveal that the terminal hydroxyls on γ-Al2O3 are responsible for anchoring Ag species. The abundant terminal hydroxyls existed on nanosized γ-Al2O3 can lead to single-atom silver dispersion, thereby resulting in markedly enhanced performance than the Ag cluster on microsized γ-Al2O3. Density-functional-theory calculations confirm that Ag atom is mainly …
Carbon Oxidation State In Microbial Polar Lipids Suggests Adaptation To Hot Spring Temperature And Redox Gradients,
2020
Arizona State University
Carbon Oxidation State In Microbial Polar Lipids Suggests Adaptation To Hot Spring Temperature And Redox Gradients, Grayson M. Boyer, Florence Schubotz, Roger E. Summons, Jade Woods, Everett L. Shock
Department of Chemistry: Faculty Publications
The influence of oxidation-reduction (redox) potential on the expression of biomolecules is a topic of ongoing exploration in geobiology. In this study, we investigate the novel possibility that structures and compositions of lipids produced by microbial communities are sensitive to environmental redox conditions. We extracted lipids from microbial biomass collected along the thermal and redox gradients of four alkaline hot springs in Yellowstone National Park (YNP) and investigated patterns in the average oxidation state of carbon (ZC), a metric calculated from the chemical formulae of lipid structures. Carbon in intact polar lipids (IPLs) and their alkyl chains becomes …
Surface Modification Of Silicon Nanowire Based Field Effect Transistors With Stimuli Responsive Polymer
Brushes For Biosensing Applications,
2020
Institute for Materials Science and Max Bergmann Center of Biomaterials
Surface Modification Of Silicon Nanowire Based Field Effect Transistors With Stimuli Responsive Polymer Brushes For Biosensing Applications, Stephanie Klinghammer, Sebastian Rauch, Sebastian Pregl, Petra Uhlmann, Larysa Baraban, Gianaurelio Cuniberti
Department of Chemistry: Faculty Publications
We demonstrate the functionalization of silicon nanowire based field effect transistors (SiNW FETs) FETs with stimuli-responsive polymer brushes of poly(N-isopropylacrylamide) (PNIPAAM) and poly(acrylic acid) (PAA). Surface functionalization was confirmed by atomic force microscopy, contact angle measurements, and verified electrically using a silicon nanowire based field effect transistor sensor device. For thermo-responsive PNIPAAM, the physicochemical properties (i.e., a reversible phase transition, wettability) were induced by crossing the lower critical solution temperature (LCST) of about 32 ◦C. Taking advantage of this property, osteosarcomic SaoS-2 cells were cultured on PNIPAAM-modified sensors at temperatures above the LCST, and completely detached by simply cooling. Next, …
Rapid And Accurate Determination Of Atomistic Rna Dynamic Ensemble Models Using Nmr And Structure Prediction,
2020
Duke University, Durham & Duke University School of Medicine, Durham
Rapid And Accurate Determination Of Atomistic Rna Dynamic Ensemble Models Using Nmr And Structure Prediction, Honglue Shi, Atul Rangadurai, Hala Abou Assi, Rohit Roy, David A. Case, Daniel Herschlag, Joseph D. Yesselman, Hashim M. Al-Hashimi
Department of Chemistry: Faculty Publications
Biomolecules form dynamic ensembles of many inter-converting conformations which are key for understanding how they fold and function. However, determining ensembles is challenging because the information required to specify atomic structures for thousands of conformations far exceeds that of experimental measurements. We addressed this data gap and dramatically simplified and accelerated RNA ensemble determination by using structure prediction tools that leverage the growing database of RNA structures to generate a con- formation library. Refinement of this library with NMR residual dipolar couplings provided an atomistic ensemble model for HIV-1 TAR, and the model accuracy was independently sup- ported by comparisons …
A Luminescence-Based System For Identification Of Genetically Encodable Inhibitors Of Protein Aggregation,
2020
University of Nebraska - Lincoln
A Luminescence-Based System For Identification Of Genetically Encodable Inhibitors Of Protein Aggregation, Travis J. Nelson, Shuo Liang, Cliff I. Stains
Department of Chemistry: Faculty Publications
Molecules that disrupt protein aggregation represent potential tool compounds for the investigation of numerous human disease states. However, the identification of small molecules capable of disrupting protein aggregation has proven challenging. Larger biomolecules such as antibodies and proteins are promising alternatives due to their increased size. Despite the promise of protein-based inhibitors, generalizable assays are needed to more readily identify proteins capable of inhibiting aggregation. Herein, we utilize our previously reported self- assembling NanoLuc luciferase fragments to engineer a platform in which both detection reagents are expressed from the same plasmid, enabling facile co-transformation with a genetically encodable inhibitor. This …
Constructing Stable And Potentially High-Performance Hybrid Organic-Inorganic Perovskites With “Unstable” Cations,
2020
Huazhong University of Science and Technology, Wuhan
Constructing Stable And Potentially High-Performance Hybrid Organic-Inorganic Perovskites With “Unstable” Cations, Qing Yang, Menghao Wu, Xiao Cheng Zeng
Department of Chemistry: Faculty Publications
A new family of functional hybrid organic-inorganic perovskites (HOIPs) is theoretically designed based on the following chemical+ insights: when a proton is adhered to molecules like water or ethanol, the newly formed larger-sized cations (e.g., H5O2 ,++ C2H5OH2 , and CH3SH ) entail low electron affinities mimicking superalkalis; they are conjugated acids of weak bases that cannot survive in solution, while their chemistry behavior in the HOIP frameworks, however, may be markedly different due to greatly enhanced cohesive energies of the proton, which facilitate the formation of new HOIPs. First-principles computations show that the putative formation reactions for these newly …
Domain Wall Conduction In Calcium-Modified Lead Titanate For Polarization Tunable Photovoltaic Devices,
2020
Northwest University, Xi’an
Domain Wall Conduction In Calcium-Modified Lead Titanate For Polarization Tunable Photovoltaic Devices, Chong-Xin Qian, Hong-Jian Hong-Jian, Qiang Zhang, Jiawei He, Zi-Xuan Chen, Ming-Zi Wang, Xiao Cheng Zeng
Department of Chemistry: Faculty Publications
Ferroelectric domain wall (DW) conduction, confirmed in recent experiments, has attracted intense attention due to its promising applications in optoelec- tronic devices. Herein, we provide theoretical evidence of electric conduction in Pb0.8Ca0.2TiO3 (PCT) DWs. The separation of charge accumulation in DWs, corresponding to the electronic conduction-band minimum (CBM) and valence-band maximum (VBM), weakens the tendency for the electron-hole recombination, thereby providing more efficient channels for charge transfer. We fabricate PCT-based functional photovoltaic devices with polarization tunable charge transfer to exploit the combined conduction and ferroelectric properties of the DW. The photovoltaic performance of the devices can be regu- lated by …
Mechanistic Insights Into The Acetate-Accelerated
Synthesis Of Crystalline Ceria Nanoparticles,
2020
University of Nebraska - Lincoln
Mechanistic Insights Into The Acetate-Accelerated Synthesis Of Crystalline Ceria Nanoparticles, Tamra J Fisher, Deepa Choudhry, Kaitlynn Derr, Soodabeh Azadehranjbar, Dan Stasko, Chin Li Cheung
Department of Chemistry: Faculty Publications
Recent increasing uses of ceria in research and industrial applications have fostered continuing developments of efficient routes to synthesize the material. Here we report our investigation of the effects and the mechanistic roles of lithium acetate to accelerate the growth of crystalline ceria nanoparticles in ozone-mediated synthesis. By increasing the mole ratio of the acetate to cerium nitrate in the reactions, the reaction yields of ceria nanoparticles were observed to increase from ca. 10% to up to over 90% by cerium content in 30 min reactions. Microscopy images and Raman spectra of the assynthesized nanoparticles revealed that increasing the acetate …
A Click-Based Modular Approach To Introduction Of Peroxides Onto Molecules And Nanostructures,
2020
University of Nebraska - Lincoln
A Click-Based Modular Approach To Introduction Of Peroxides Onto Molecules And Nanostructures, Alissa Horn, Patrick H. Dussault
Department of Chemistry: Faculty Publications
Copper-promoted azide/alkyne cycloadditions (CuAAC) are explored as a tool for modular introduction of peroxides onto molecules and nanomaterials. Dialkyl peroxide-substituted alkynes undergo Cu(I)- promoted reaction with azides in either organic or biphasic media to furnish peroxide-substituted 1,2,3- triazoles. Heterolytic fragmentation of the peroxide to an aldehyde, a side reaction that appears to be related to the formation of the triazole, can be suppressed by use of excess alkyne, the presence of triethylsilane, or by use of iodoalkyne substrates. Complementary reactions of simple alkynes with azidosubstituted peroxides are much less efficient. Click reactions of alkynyl peroxyacetals are also reported; reductive fragmentation …
Agbis2 As A Low-Cost And Eco-Friendly All-Inorganic
Photovoltaic Material: Nanoscale Morphology–
Property Relationship†,
2020
University of Nebraska-Lincoln
Agbis2 As A Low-Cost And Eco-Friendly All-Inorganic Photovoltaic Material: Nanoscale Morphology– Property Relationship†, Ming-Gang Ju, Jun Dai, Liang Ma, Yuanyuan Zhou, Xiao Cheng Zeng
Department of Chemistry: Faculty Publications
Solar cells made of low-cost solution-processed all-inorganic materials are a promising alternative to conventional solar cells made of high-temperature processed inorganic materials, especially because many high-temperature processed inorganic materials contain toxic element(s) such as lead or cadmium (e.g., CsPbI3 perovskite, PbS, CdTe and CdS(Se)). AgBiS2 nanocrystals, consisting of earth-abundant elements but without lead and cadmium, have already emerged as a promising candidate in highperformance solar cells. However, the nanoscale morphology–optoelectronic property relationship for AgBiS2 nanocrystals is still largely unknown. Herein, we investigate the electronic properties of various AgBiS2 nanocrystals by using first-principles computation. We show that …
Ionic Liquid Functionalized Β-Cyclodextrin Modified Electrode As Electrochemical Sensor For 2,4-Dichlorophenol,
2020
Universiti Malaya
Ionic Liquid Functionalized Β-Cyclodextrin Modified Electrode As Electrochemical Sensor For 2,4-Dichlorophenol, Fairuz Liyana Mohd Rasdi
Student Works (2020-2029)
This thesis described the synthesis and characterization of ionic liquid monofunctionalized β-cyclodextrin (β-CD-1-BIMOTs) and ionic liquid difunctionalized β-cyclodextrin (β-CD-2-BIMOTs) for sensor applications. The physical characterizations of these compounds have been conducted using nuclear magnetic resonance (NMR), Fourier transform infra-red (FTIR), energy dispersive x-ray (EDX), x-ray diffraction (XRD) and Brunauer-Emmet-Teller (BET) analyses. These compounds were used as modifiers for carbon paste electrode (CPE). Cyclic voltammetry and chrono-amperometry methods were employed to examine the electrochemical responses of all prepared CPEs. All prepared electrodes show responses towards the target analyte of 2,4-dichlorophenol (2,4-DCP). Both β-CD-1-BIMOTs/CPE and β-CD-2-BIMOTs/CPE give higher current (i) responses compared …
Development And Validation Of Advanced Analytical Methods For Pesticides, Per- And Polyfluoroalkyl Substances, And Opioids In Soil And Drinking Water,
2020
South Dakota State University
Development And Validation Of Advanced Analytical Methods For Pesticides, Per- And Polyfluoroalkyl Substances, And Opioids In Soil And Drinking Water, Christopher Skaggs
Electronic Theses and Dissertations
Environmental pollution from contaminants is a serious concern in a world where more and more pesticides and pharmaceuticals are being used, sometimes improperly and in excess. Since pesticides are used on practically every crop on Earth, it’s no surprise that these compounds are detected in soil, water, and processed agricultural commodities meant for human consumption. Additionally, because of the ubiquity of pharmaceuticals, specifically opioids, and their inherent addictive properties, these compounds are being over-consumed. Because current waste-water treatments can be insufficient to remove them from water sources, this consumption has led to the detection of these compounds in drinking water. …
Structural Annotation Of Electro- And Photochemically Generated Transformation Products Of Moxidectin Using High-Resolution Mass Spectrometry,
2020
BAM, Germany
Structural Annotation Of Electro- And Photochemically Generated Transformation Products Of Moxidectin Using High-Resolution Mass Spectrometry, Lisa Kotthoff, Sarah-Louise O'Callaghan, Jan Lisec, Tanja Schwerdtle, Matthias Koch
Articles
Moxidectin (MOX) is a widely used anthelmintic drug for the treatment of internal and external parasites in food-producing and companion animals. Transformation products (TPs) of MOX, formed through metabolic degradation or acid hydrolysis, may pose a potential environmental risk, but only few were identified so far. In this study, we therefore systematically characterized electro- and photochemically generated MOX TPs using high-resolution mass spectrometry (HRMS). Oxidative electrochemical (EC) TPs were generated in an electrochemical reactor and photochemical (PC) TPs by irradiation with UV-C light. Subsequent HRMS measurements were performed to identify accurate masses and deduce occurring modification reactions of derived TPs …
