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2016

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Articles 1381 - 1410 of 1436

Full-Text Articles in Chemistry

Unraveling The Hidden Function Of A Stabilizer In A Precursor In Improving Hybrid Perovskite Film Morphology For High Efficiency Solar Cells, Zhengguo Xiao, Dong Wang, Qingfeng Dong, Qi Wang, Wei Wei, Jun Dai, Xiwei Zheng, Jinsong Huang Jan 2016

Unraveling The Hidden Function Of A Stabilizer In A Precursor In Improving Hybrid Perovskite Film Morphology For High Efficiency Solar Cells, Zhengguo Xiao, Dong Wang, Qingfeng Dong, Qi Wang, Wei Wei, Jun Dai, Xiwei Zheng, Jinsong Huang

Xiao Cheng Zeng Publications

The morphology of the organometal trihalide perovskite (OTP) plays a critical role in the performance of solar cell devices. Nevertheless it has been frequently reported that the morphology of OTP films tends to be different in different laboratories even with the same film preparation procedure, which makes it very difficult to compare and understand the material and device physics. Here, we unravel a critical role of the H3PO2 stabilizer in HI, which has been largely ignored, in controlling the morphology of the perovskite films. The H3PO2 stabilizer in HI solution introduces MAH2PO …


Hydrogen Bonding And Orientation Effects On The Accommodation Of Methylamine At The Air-Water Interface, Ross D. Hoehn, Marcelo A. Carignano, Sabre Kais, Chongjing Zhu, Xiao Cheng Zeng, Joseph S. Francisco, Ivan Gladich Jan 2016

Hydrogen Bonding And Orientation Effects On The Accommodation Of Methylamine At The Air-Water Interface, Ross D. Hoehn, Marcelo A. Carignano, Sabre Kais, Chongjing Zhu, Xiao Cheng Zeng, Joseph S. Francisco, Ivan Gladich

Xiao Cheng Zeng Publications

Methylamine is an abundant amine compound detected in the atmosphere which can affect the nature of atmospheric aerosol surfaces, changing their chemical and optical properties. Molecular dynamics simulation results show that methylamine accommodation on water is close to unity with the hydrophilic head group solvated in the interfacial environment and the methyl group pointing into the air phase. A detailed analysis of the hydrogen bond network indicates stronger hydrogen bonds between water and the primary amine group at the interface, suggesting that atmospheric trace gases will likely react with the methyl group instead of the solvated amine site. These findings …


Tuning The Electronic Properties Of Monolayer And Bilayer Ptse2 Via Strain Engineering, Pengfei Li, Lei Li, Xiao Cheng Zeng Jan 2016

Tuning The Electronic Properties Of Monolayer And Bilayer Ptse2 Via Strain Engineering, Pengfei Li, Lei Li, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The recently synthesized monolayer PtSe2 belongs to the class of two-dimensional transition metal dichalcogenide (TMDC) materials (Nano Lett., 2015, 15, 4013). Based on first-principles calculations, we show that the band gaps of monolayer and bilayer PtSe2 can be tuned over a wide range via strain engineering. Both isotropic and uniaxial strains are investigated. For bilayer PtSe2, the vertical out-of-plane strain is also considered. In most cases, the strain can reduce the band gap except for the bilayer PtSe2 under the isotropic strain (Ɛ≤ 4%) for which the band gap can be slightly enlarged. Importantly, the …


Near-Barrierless Ammonium Bisulfate Formation Via A Loop-Structure Promoted Proton-Transfer Mechanism On The Surface Of Water, Lei Li, Manoj Kumar, Chongqin Zhu, Jie Zhong, Joseph S. Francisco, Xiao Cheng Zeng Jan 2016

Near-Barrierless Ammonium Bisulfate Formation Via A Loop-Structure Promoted Proton-Transfer Mechanism On The Surface Of Water, Lei Li, Manoj Kumar, Chongqin Zhu, Jie Zhong, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

In the atmosphere, a well-known and conventional pathway toward the formation of ammonium sulfate is through the neutralization of sulfuric acid with ammonia (NH3) in water droplets. Here, we present direct ab initio molecular dynamics simulation evidence of the formation of ammonium bisulfate (NH4HSO4) from the hydrated NH3 and SO3 molecules in a water trimer as well as on the surface of a water droplet. This reaction suggests a new mechanism for the formation of ammonium sulfate in the atmosphere, especially when the concentration of NH3 is high (e.g., ∼10 μg …


Resolving The Hono Formation Mechanism In The Ionosphere Via Ab Initio Molecular Dynamic Simulations, Rongxing He, Lei Li, Jie Zhong, Chongqin Zhu, Joseph S. Francisco, Xiao Cheng Zeng Jan 2016

Resolving The Hono Formation Mechanism In The Ionosphere Via Ab Initio Molecular Dynamic Simulations, Rongxing He, Lei Li, Jie Zhong, Chongqin Zhu, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Solar emission produces copious nitrosonium ions (NO+) in the D layer of the ionosphere, 60 to 90 km above the Earth’s surface. NO+ is believed to transfer its charge to water clusters in that region, leading to the formation of gaseous nitrous acid (HONO) and protonated water cluster. The dynamics of this reaction at the ionospheric temperature (200–220 K) and the associated mechanistic details are largely unknown. Using ab initio molecular dynamics (AIMD) simulations and transition-state search, key structures of the water hydrates—tetrahydrate NO+(H2O)4 and pentahydrate NO+(H2O)5 …


Probing The Structures Of Gold–Aluminum Alloy Clusters AuXAlY−: A Joint Experimental And Theoretical Study, Navneet S. Khetrapal, Tian Jian, Rhitankar Pal, Gary V. Lopez, Seema Pande, Lai-Sheng Wang, Xiao Cheng Zeng Jan 2016

Probing The Structures Of Gold–Aluminum Alloy Clusters AuXAlY−: A Joint Experimental And Theoretical Study, Navneet S. Khetrapal, Tian Jian, Rhitankar Pal, Gary V. Lopez, Seema Pande, Lai-Sheng Wang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Besides the size and structure, compositions can also dramatically affect the properties of alloy nanoclusters. Due to the added degrees of freedom, determination of the global minimum structures for multi-component nanoclusters poses even greater challenges, both experimentally and theoretically. Here we report a systematic and joint experimental/theoretical study of a series of gold–aluminum alloy clusters, AuxAly−(x + y = 7,8), with various compositions (x = 1–3; y = 4–7). Well-resolved photoelectron spectra have been obtained for these clusters at different photon energies. Basin-hopping global searches, coupled with density functional theory calculations, are used …


Synthesis Of Dmap Tethered Polymer Chains For Reversible Micelle Formation, Richard Arthur Fredricks Jan 2016

Synthesis Of Dmap Tethered Polymer Chains For Reversible Micelle Formation, Richard Arthur Fredricks

Master's Theses and Doctoral Dissertations

Dimethylaminopyridine (DMAP) can act to catalyze numerous organic reactions. To increase its recovery and reuse, it has been tethered to dendrimers and to micellar systems, creating nano-scale catalytic pockets for reactions to proceed. Previously developed systems show diminished reactivity over time as the products of the reaction fill up the nano-scale reactor. Thus, the goal of my research is to use RAFT polymerization methods to synthesize a hydrophobic polymer chain bearing 4-methylaminopyridine units and to attach it to a hydrophilic polymer chain to create a polymer system capable of micelle formation in solution. These functionalized micelles are designed to be …


Electropolymerized Layersas Selective Membranesin First Generation Uric Acid Biosensors, Kaiwen Chen, Grace E. Conway, Gregory A. Hamilton, Matthew L. Trawick, Michael C. Leopold Jan 2016

Electropolymerized Layersas Selective Membranesin First Generation Uric Acid Biosensors, Kaiwen Chen, Grace E. Conway, Gregory A. Hamilton, Matthew L. Trawick, Michael C. Leopold

Chemistry Faculty Publications

Electropolymerized films that can serve as semi-permeable membranes and provide selectivity within a xerogel-based, 1stgeneration biosensor assembly are explored in this study. Layered biosensing schemes of this nature rely primarily upon an electropolymerized ad-layer to supplement the xerogel and provide effective selectivity for detection of a targeted analyte. While effective electropolymers have been established for glucose sensing, the adaptation of the strategy to other analytes of clinical importance hinges upon the systematic evaluation of electropolymerized films to identify a selective film. Uric acid is a key species in the diagnosis/monitoring of a number of diseases and conditions. An …


Tandem Mass Spectrometric Analysis Of Phosphoamino Acid-Metal Ion Complexes, Urmi Patel Jan 2016

Tandem Mass Spectrometric Analysis Of Phosphoamino Acid-Metal Ion Complexes, Urmi Patel

All Capstone Projects

The complex of phosphoamino acid with metal ions was prepared by mixing both solutions and analyzed using ESI MS/MS technique. In this study, O-phospho-L-serine and O-phospho-L-tyrosine were used as phosphoamino acids and single charged metal ions such as Li+, Na+, K+, Rb+, Cs+ and Ag+ were used to study the dissociation patterns when combined with phosphoamino acid. The complexes were successfully fragmented in mass spectra using ESI MS/MS technique and the fragmentation products were studied and the dissociation patterns were proposed.


Bioactivity/Cytotoxicity Of Micro-/Nano-Materials And Novel Development Of Fiber-Optic Probes For Single Cell Monitoring, Qingbo Yang Jan 2016

Bioactivity/Cytotoxicity Of Micro-/Nano-Materials And Novel Development Of Fiber-Optic Probes For Single Cell Monitoring, Qingbo Yang

Doctoral Dissertations

"Manufactured nano-/micro-materials (MNMs) have been widely used and their interactions with niche biological environment are highly concerned for both of their biohazardous and bioactive effects, whereas no available comprehensive evaluations or regulations have been provided yet. This dissertation thus focuses on three major aspects: 1) fundamental toxicity understandings of a typical MNMs (zinc oxide nanoparticles), 2) bioactivity evaluations of representative bioactive MNMs, and 3) development of novel micro-probes for high spatial resolution monitoring. Firstly, the NP's concentration, irradiation, hydrodynamic size, and the localized pH, ionic strength, NP zeta-potential as well as dissolved oxygen levels were found correlated with the production …


The Onset Of Electron-Induced Proton-Transfer In Hydrated Azabenzene Cluster Anions, Yi Wang, Xinxing Zhang, Svetlana Lyapustina, Michael M. Nilles, Shoujun Xu, Jacob D. Graham, Kit H. Bowen, John T. Kelly, Gregory S. Tschumper, Nathan I. Hammer Jan 2016

The Onset Of Electron-Induced Proton-Transfer In Hydrated Azabenzene Cluster Anions, Yi Wang, Xinxing Zhang, Svetlana Lyapustina, Michael M. Nilles, Shoujun Xu, Jacob D. Graham, Kit H. Bowen, John T. Kelly, Gregory S. Tschumper, Nathan I. Hammer

Chemistry Faculty Research & Creative Works

The prospect that protons from water may be transferred to N-heterocyclic molecules due to the presence of an excess electron is studied in hydrated azobenzene cluster anions using anion photoelectron spectroscopy and computational chemistry. In the case of s-triazine (C3H3N3), which has a positive adiabatic electron affinity, proton transfer is not energetically favored nor observed experimentally. Heterocyclic rings with only 1 or 2 nitrogen atoms have negative electron affinities, but the addition of solvating water molecules can yield stable negative ions. In the case of the diazines (C4H4N2: …


Blended Learning In Chemistry Laboratory Courses: Enhancing Learning Outcomes And Aligning Student Needs With Available Resources, Shayna Brianne Burchett Jan 2016

Blended Learning In Chemistry Laboratory Courses: Enhancing Learning Outcomes And Aligning Student Needs With Available Resources, Shayna Brianne Burchett

Doctoral Dissertations

"Freshman science courses are intended to prepare students for the rigor and expectations of subsequent college science. While secondary education aims to prepare students for the college curriculum, many incoming freshman lack the sense of responsibility for their own learning that is essential for success in a college-level course. The freshman general-chemistry laboratory course at Missouri University of Science and Technology (Missouri S&T) was identified as a bottleneck course with a demand beyond accommodation capacity. To address the bottleneck and develop a sense of learner responsibility, a decision was made to investigate laboratory course delivery strategies. As a result of …


Effect Of Disulfide Bond Scrambling On Protein Stability, Aggregation, And Cytotoxicity, Colina Dutta Jan 2016

Effect Of Disulfide Bond Scrambling On Protein Stability, Aggregation, And Cytotoxicity, Colina Dutta

Dissertations, Master's Theses and Master's Reports

Proteins are nano-machines that carry out majority of the cellular functions. Thermodynamically they are functional and stable within a very narrow range (1 kcal/mol). External perturbations in the form of pH change, thermal, or oxidative/reducing stress can destabilize the protein resulting in misfolding and aggregation. Prolonged environmental stress can affect the cells adaptive response resulting in loss of ability to refold or recycle proteins. This can lead to accumulation of misfolded or aggregated proteins within the cell. Such accumulation of aggregated proteins have been associated with neurodegenerative disorders such as Amyotrophic Lateral Sclerosis (ALS), Parkinson’s, Huntington’s, and Alzheimer’s disease. There …


Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices, Yongbo Dan Jan 2016

Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices, Yongbo Dan

Doctoral Dissertations

"As the rapid growing of nanotechnology, the release of engineered nanoparticles (ENPs) into the environment is inevitable. After entering the real environment, ENPs tend to react with different components of the ecosystem (e.g. water, soil, air, plants) and make their characterization difficult. Analyzing ENPs in these complex matrices still remains as a grand challenge. ENPs characterization is normally the first step of risk assessment. Current analytical techniques have shown some limitations in revealing the unique characteristics of ENPs in complex matrices and reliable analytical techniques are in urgent need. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is an emerging …


พอลิเมอร์ผสมของพอลิแล็กทิกแอซิดและเซลลูโลสแอซีเทตจากผักตบชวา, กรองกาญจน์ อมตาริยกุล Jan 2016

พอลิเมอร์ผสมของพอลิแล็กทิกแอซิดและเซลลูโลสแอซีเทตจากผักตบชวา, กรองกาญจน์ อมตาริยกุล

Chulalongkorn University Theses and Dissertations (Chula ETD)

เซลลูโลสอะซิเทดถูกสังเคราะห์โดยใช้เซลลูโลสผักตบชวาเป็นวัตถุดิบ ซึ่งส่วนที่ใช้จะเป็นส่วนของก้านขั้นตอนแรกนำเส้นใยผักตบชวาไปกำจัดสิ่งสกปรกก้านแห้งและตามมาด้วยการฟอกสีไฮโปคลอไรเซลลูโลสให้เป็นสีขาวสีขาวแล้ว หลังจากนั้นเตรียมเซลลูโลสเจลโดยใช้โซเดียมไฮดรอกไซด์ / ยูเรีย / น้ำ (7:12:81 โดยน้ำหนัก) จากนั้นนำมาผสม ปริมาณของไวนิลอะซิเตทโดยมีอัตราส่วนต่างกันคือ 3.0, 5.0, 7.0, 9.0, 11.0% โดยน้ำหนักของเซลลูโลส หลังจากนั้นส่วนผสมที่ถูกเก็บไว้ในตู้แช่แข็งเป็นเวลา 6 ชั่วโมงเพื่อให้เกิดปฏิกิริยาแอซิทิเลชันสมบูรณ์ เซลลูโลสอะซิเตทมีความสามารถในการปรับปรุงคุณสมบัติของพอลิแล็กทิกแอซิดโดยการเปลี่ยนเป็นผลึกที่สมบัติเชิงกลและสมบัติทางความร้อน จุดมุ่งหมายของการศึกษาครั้งนี้คือการสังเคราะห์ เซลลูโลสแอซิเทดจากผักตบชวาโดยใช้พอลิไวนิลอะซิเตตสารช่วยเพิมความเข้ากันได้ (Compatiblizer) จากนั้นพอลิแล็กทิกแอซิด / เซลลูโลสอะซิเทดนำไปผสมกันโดยใช้เครื่องอัดรีดเกลียว หลังจากนั้นนำไปวิเคราะผล ดังนี้ วิเคราะห์หมู่ฟังก์ชันโดยใช้ฟูเรียทรานสฟอร์มสเปกโตรสโคปี (FTIR) วิเคราห์ความเป็นผลึกด้วยเครื่องเอกซ์เรย์ดิฟแฟรกโทรมิเตอร์(XRD) และ วิเคราะห์สัณฐานวิทยาด้วยกล้องจุลทรรศน์อิเล็กตรอนแบบส่องกราด(SEM) พบว่าพอลิแล็กทิกแอซิด / เซลลูโลสอะซิเตทโดยความเข้มข้นที่เหมาะสมที่สุดของเซลลูโลสอะซิเตทสำหรับการผสมกับพอลิแล็กทิกแอซิด เป็น 11% โดยน้ำหนักและสัดส่วนของพอลิแล็กทิกแอซิด/เซลลูโลสแอซิเทดคือ 95 : 5


Enabling Method To Design Versatile Biomaterial Systems From Colloidal Building Blocks, Shalini Saxena, L. Andrew Lyon Jan 2016

Enabling Method To Design Versatile Biomaterial Systems From Colloidal Building Blocks, Shalini Saxena, L. Andrew Lyon

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Development of materials with fine spatial control over topographical, mechanical, or chemical features has been investigated for a variety of applications. Here we present a method to fabricate an array of polyelectrolyte constructs including two-dimensionally and three-dimensionally patterned assemblies using both compressible and incompressible colloidal building blocks. This method eliminates prior constraints associated with specific chemistries, and can be used to develop modular, multi-component, patterned assemblies. In particular, development of constructs were investigated using microgels, which are colloidally stable hydrogel microparticles, polystyrene (PS) beads, and PS-microgel core-shell building blocks in conjunction with the polycation poly(ethyleneimine) (PEI). The topography, mechanical properties, …


Physical And Electrochemical Area Determination Of Electrodeposited Ni, Co, And Nico Thin Films, Matthew Gira, Kevin Tkacz, Jennifer R. Hampton Jan 2016

Physical And Electrochemical Area Determination Of Electrodeposited Ni, Co, And Nico Thin Films, Matthew Gira, Kevin Tkacz, Jennifer R. Hampton

Faculty Publications

The surface area of electrodeposited thin films of Ni, Co, and NiCo was evaluated using electrochemical double-layer capacitance, electrochemical area measurements using the [Ru(NH3)6]3+/[Ru(NH3)6]2+ redox couple, and topographic atomic force microscopy (AFM) imaging. These three methods were compared to each other for each composition separately and for the entire set of samples regardless of composition. Double-layer capacitance measurements were found to be positively correlated to the roughness factors determined by AFM topography. Electrochemical area measurements were found to be less correlated with measured roughness factors as well as applicable …


Investigating Alaskan Methane And Carbon Dioxide Fluxes Using Measurements From The Carve Tower, Anna Karion, Colm Sweeney Colm Sweeney, John B. Miller John B. Miller, Arlyn E. Andrews, Roisin Commane, Steven Dinardo, John M. Henderson, Jacob Lindaas, John C. Lin, Kristina Luus, Tim Newberger, Pieter Tans Pieter Tans, Steven C. Wofsy, Sonja Wolter, Charles E. Miller Jan 2016

Investigating Alaskan Methane And Carbon Dioxide Fluxes Using Measurements From The Carve Tower, Anna Karion, Colm Sweeney Colm Sweeney, John B. Miller John B. Miller, Arlyn E. Andrews, Roisin Commane, Steven Dinardo, John M. Henderson, Jacob Lindaas, John C. Lin, Kristina Luus, Tim Newberger, Pieter Tans Pieter Tans, Steven C. Wofsy, Sonja Wolter, Charles E. Miller

Articles

Northern high-latitude carbon sources and sinks, including those resulting from degrading permafrost, are thought to be sensitive to the rapidly warming climate. Because the near-surface atmosphere integrates surface fluxes over large ( ∼ 500–1000 km) scales, atmospheric monitoring of carbon dioxide (CO2) and methane (CH4) mole fractions in the daytime mixed layer is a promising method for detecting change in the carbon cycle throughout boreal Alaska. Here we use CO2 and CH4 measurements from a NOAA tower 17 km north of Fairbanks, AK, established as part of NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), to investigate regional fluxes of …


Regional Effects Of Streptozotocin-Induced Diabetes On Shortening And Calcium Transport In Epicardial And Endocardial Myocytes From Rat Left Ventricle, Manal M.A. Smaill, Muhammad A. Qureshi, Anatoliy Shmygol, Murat Oz, Jaipaul Singh, Vadym Sydorenko, Alya Arabi, Frank C. Howarth, Lina Al Kury Jan 2016

Regional Effects Of Streptozotocin-Induced Diabetes On Shortening And Calcium Transport In Epicardial And Endocardial Myocytes From Rat Left Ventricle, Manal M.A. Smaill, Muhammad A. Qureshi, Anatoliy Shmygol, Murat Oz, Jaipaul Singh, Vadym Sydorenko, Alya Arabi, Frank C. Howarth, Lina Al Kury

All Works

© 2016 The Authors. In the heart, the left ventricle pumps blood at higher pressure than the right ventricle. Within the left ventricle, the electromechanical properties of ventricular cardiac myocytes vary transmurally and this may be related to the gradients of stress and strain experienced in vivo across the ventricular wall. Diabetes is also associated with alterations in hemodynamic function. The aim of this study was to investigate shortening and Ca2+ transport in epicardial (EPI) and endocardial (ENDO) left ventricular myocytes in the streptozotocin (STZ)-induced diabetic rat. Shortening, intracellular Ca2+ and L-type Ca2+ current (ICa,L) were measured by video detection, …


Ionic Liquid Based Fluorescent Sensors For Cations, Jaelene M. Torres Jan 2016

Ionic Liquid Based Fluorescent Sensors For Cations, Jaelene M. Torres

Theses, Dissertations and Culminating Projects

The development of novel fluorescent sensors for cations is an area of current interest. Most of these sensors are large organic molecules that have a low solubility in water and are not suitable to be used as sensors in water. The goal of this study is to develop a new sensor by attaching an ionic liquid group to make it water-soluble. We have used a well-known photoinduced electron transfer (PET) sensor for protons as our first test. This sensor is based on a chromophore-spacer-receptor design that is based on an anthracene chromophore and a morpholine proton receptor. The sensor is …


The Utilization Of Liquid Chromatography Tandem Mass Spectrometry And Related Techniques For The Analysis And Identification Of Emerging Contaminants In Aqueous Matrices, Matthew Reichert Jan 2016

The Utilization Of Liquid Chromatography Tandem Mass Spectrometry And Related Techniques For The Analysis And Identification Of Emerging Contaminants In Aqueous Matrices, Matthew Reichert

Dissertations

Environmental pollutants can be found in many ecosystems and cover many different compound classes. The Environmental Protection Agency is responsible for monitoring and regulating several of these classes of compounds which daily enter the environment. However, there are still hundreds, if not thousands, of compounds present in the environment which have yet to be regulated or even identified. The discovery and identification of these unknown emerging pollutants is crucial for the prevention of potential human health risks and irreversible ecological damage.

The research presented is divided into two projects. The first part of this research investigates the disinfectant 3-Bromo-1-chloro-5,5-dimethylhydantoin, which …


Awareness Of Clinical Laboratory Sciences And Shortage Of Clinical Laboratory Scientists In The 21st Century, Cynthia Funnye Doby Jan 2016

Awareness Of Clinical Laboratory Sciences And Shortage Of Clinical Laboratory Scientists In The 21st Century, Cynthia Funnye Doby

Walden Dissertations and Doctoral Studies

Retiring baby boomers and the lack of interest and awareness among college students to enroll in an accredited Clinical Laboratory Science (CLS) program have created a shortage of CLS professionals in the 21st century. The U.S. Bureau of Labor Statistics predicts 18,000 CLS vacancies by 2018. However, only about 5,000 students graduate from accredited CLS programs each year. The purpose of this study was to explore students' perceptions of allied health professions and factors that influenced students and CLS professionals to select CLS as a profession. Bandura's social cognitive career theory served as the theoretical framework for this phenomenological study. …


Seasonal Evolution Of Active Layer Formation In Subarctic Peat Plateaux And Implications For Dissolved Organic Matter Composition And Transfer, Jennifer L. Hickman Jan 2016

Seasonal Evolution Of Active Layer Formation In Subarctic Peat Plateaux And Implications For Dissolved Organic Matter Composition And Transfer, Jennifer L. Hickman

Theses and Dissertations (Comprehensive)

Peat-accumulating wetlands are ecosystems whose rate of photosynthetic production of organic matter is greater than that of its decomposition, resulting in a build up of soil organic matter that may take centuries to fully decompose. Carbon (C) stocks within these ecosystems are a function of inputs from photosynthesis, and losses from heterotrophic decomposition. Due to the short growing season and overall cold climate of boreal and tundra regions, C has been accumulating within these landscapes, mostly in soil organic matter, since the last glaciation. Climate change, predicted to result in rising temperatures and increased precipitation, has begun to degrade the …


Sm And Dy Interaction With Dissolved Organic Matter (Dom) In Freshwater Measured By Ion-Selective Electrode And Fluorescence Quenching Analytical Techniques, Alexandra Carvajal Jan 2016

Sm And Dy Interaction With Dissolved Organic Matter (Dom) In Freshwater Measured By Ion-Selective Electrode And Fluorescence Quenching Analytical Techniques, Alexandra Carvajal

Theses and Dissertations (Comprehensive)

With the increased demand for lanthanide metals in various industries, companies are looking into mining of these metals in Northern Canada. The release of these metals into the environment may have adverse effect on aquatic ecosystems; thus, it is important to understand potential toxicological effects of lanthanides on aquatic organisms. One way to predict these effects is by using a Biotic Ligand Model (BLM). Although incorporation of lanthanides into the model will require a substantial amount of future research, initial studies into speciation and toxicity can provide a useful basis for future reference. There are two main objectives to this …


Phosphorus Removal Using Titanium Dioxide Nanoparticles In Wastewater Treatment, Suyoung Choi Mr. Jan 2016

Phosphorus Removal Using Titanium Dioxide Nanoparticles In Wastewater Treatment, Suyoung Choi Mr.

Theses and Dissertations (Comprehensive)

Due to eutrophication caused by nutrients such as phosphorus (P), local surface water near military garrisons and camps has been deteriorated for several years in the Republic of Korea. Thus, in order to remove excessive P in local fresh water, various size of titanium dioxide (TiO2) were used.

In the first investigation, TiO2 mixed bulk powder (particle size > 5µm) showed maximum P removal with pH dependence (higher pH shows lower P removal), that was approximately 27%. To determine adsorption isotherms, Langmuir and Freudlich models were used. The experimental data was better fit by a Langmuir model compared …


Chemical Removal Of Total Phosphorus From Wastewater To Low Levels And Its Analysis, Farah Ateeq Jan 2016

Chemical Removal Of Total Phosphorus From Wastewater To Low Levels And Its Analysis, Farah Ateeq

Theses and Dissertations (Comprehensive)

Numerous studies have been conducted on the removal of inorganic phosphorus (P) from wastewater, but a push towards lower effluent targets necessitates the additional removal of organic phosphorus as well. This study tested the ability of manganese oxide nanoparticles and iron oxide as potential catalysts for conversion of organic P into more readily removable inorganic forms, as well as the role of iron(III) chloride as coagulant to subsequently allow P to be removed by solids/liquid separation. Removals of 99-101% were obtained for model compounds at pH 5-7, 0.05-0.5 M H2O2, and Fe:P molar ratio of 5:1. …


Synthesis And Characterization Of Uranyl Dipyrrin Complexes For Environmental Applications, Duer Bolotaulo Bolotaulo Jan 2016

Synthesis And Characterization Of Uranyl Dipyrrin Complexes For Environmental Applications, Duer Bolotaulo Bolotaulo

Open Access Theses & Dissertations

Persistent organic pollutants (POPs) are toxic chemicals that adversely affect the health of human populations as well as the environment. The need to develop remediation methods and materials as well as understand the mechanisms in which they can degrade POPs is necessary. Furthermore, heterogeneous phase metal based catalysts in place today do not fully understand the chemistry underlying degradation processes. The proposed research seeks to synthesize and characterize uranyl dipyrrin complexes to assess and understand the reactivity of uranyl dipyrrins with pollutants. Photophysical and electrochemical techniques will be used to characterize and determine the viability of utilizing the uranyl complexes …


New Organosilicon Chemistry, Paulina Elena Gonzalez Navarro Jan 2016

New Organosilicon Chemistry, Paulina Elena Gonzalez Navarro

Open Access Theses & Dissertations

The formation of siloxymethylamine intermediates R3SiOCH 2NMe2, 1, as initial products of the reduction of DMF by hydrosilanes catalyzed by Mo(CO)5NMe3 has been reported. These siloxymethylamines can react with R’3SiH to form trimethylamine and disiloxanes, and with chlorosilanes to form disiloxanes and ClCH 2NMe2, Eschenmoser’s salt. I shall illustrate, in Chapter 1, how attempts to react 1, formed in situ in the presence of chlorosilanes R’3SiCl in the hope producing heterosilyl disiloxanes, R3SiOSiR’3, was not successful but led to a newly discovered activation of the Si-Cl bond by DMF.

In Chapter 2, we surmised that 1 acts as a transient …


Removal Of Endocrine Disrupting Compounds From Water And Wastewater Using Ecofriendly Materials, Alma Lili Loya Posada Jan 2016

Removal Of Endocrine Disrupting Compounds From Water And Wastewater Using Ecofriendly Materials, Alma Lili Loya Posada

Open Access Theses & Dissertations

Endocrine disrupting chemicals (EDCs) are compounds considered pollutants of emerging concern. The United States Environmental Protection Agency (USEPA) defines emerging pollutants as new chemicals without regulatory status and with an impact on the environment and human health that is poorly understood. Bisphenol A (BPA) has been considered an EDC and found to be ubiquitous in the environment because of its presence in a multitude of products including food and beverage packaging, flame retardants, adhesives, building materials, electronic components, and paper coatings Currently, BPA is not regulated by the federal government in the US and waste water treatment plants are not …


Identifying Non-Classical Active Sites As A Tool For Enzyme Inhibition, Marisol Serrano Jan 2016

Identifying Non-Classical Active Sites As A Tool For Enzyme Inhibition, Marisol Serrano

Open Access Theses & Dissertations

Chagas disease, caused by the parasite Trypanosoma cruzi, is an endemic life-threatening disease that affects mainly the heart. It remains the leading cause of heart failure in Latin American countries. Since current treatments against this parasite are highly toxic and somewhat ineffective, novel and more efficacious types of interventions are desired. Cruzain, identified as the major cathepsin for T. cruzi, plays a major role in the parasite's life cycle; making this enzyme very attractive for potential trypanocidal drugs discovery. The recombinant cruzain is synthesized as a zymogenic pro-protein (PCZN) which possesses a pro domain and a catalytic domain. In this …