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Full-Text Articles in Physical Sciences and Mathematics

Investigation Of A Novel Method For Polonium-210 Determination In Groundwater, Tara Matheny Dec 2011

Investigation Of A Novel Method For Polonium-210 Determination In Groundwater, Tara Matheny

All Theses

A novel method was investigated for the quantification of 210Po in water as an alternative to the standard method of spontaneous plating onto Ag disks followed by quantification with an alpha spectrometer. The novel method concentrated a 0.5L sample by MnO2 co-precipitation followed by dissolution of the precipitate into a solution. Polonium-210 was separated from the solution and quantified in a column containing a 50:50 by volume mixture of Pb resin (Eichrom Technologies, Inc.) mixed with granulated CaF2:Eu scintillator. The column containing 210Po is quantified on a liquid scintillation counter without the introduction of liquid cocktail. The minimum detectable concentration …


Prevention Of Iron- And Copper-Mediated Oxidative Dna Damage By Neurotransmmitters And Related Compounds: Evidence For Metal Binding As An Antioxidant Mechanism, Carla Garcia Dec 2011

Prevention Of Iron- And Copper-Mediated Oxidative Dna Damage By Neurotransmmitters And Related Compounds: Evidence For Metal Binding As An Antioxidant Mechanism, Carla Garcia

All Theses

An array of health concerns have been attributed to oxidative DNA damage from the hydroxyl radical (*OH), and the presence of the most biologically available metals iron and copper perpetuate the production of this radical through the Fenton and Fenton-like reactions, respectively. The concentrations at which flavonol and polyphenol antioxidants prevent 50% of DNA damage (IC50) were measured using gel electrophoresis assays upon Fe(II)/H2O2- and Cu(I)/H2O2-mediated DNA damage (Chapter 2). Results show that catechol- and gallol-containing antioxidants differ greatly in preventing DNA damage by Cu(I)/H2O2, compared to Fe(II)/H2O2, behavior that was explained using electron paramagnetic resonance spectroscopy. Semiquinone and other …


An Investigation Of The Effectiveness Of Gestures To Enhance Concept Retention In Chemistry Instruction, Jeffrey Lamb Aug 2011

An Investigation Of The Effectiveness Of Gestures To Enhance Concept Retention In Chemistry Instruction, Jeffrey Lamb

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The emergence of embodied cognition as a theory of learning has placed new emphasis on the interdependent relationship between what the mind perceives and what the body experiences. Movement and objects in the physical environment take on significant roles in the process of learning within this view and the role of gesturing in cognition has become increasingly interesting. Significant research suggests that the physical process of gesturing is connected to how the mind processes information. Gesturing during the recall of information is a universally known phenomena and one that seems to aid in the process of recall. More recent findings …


Incorporation Of Novel Diphosphines Into Polymer Structure For Light Absorption And Emission Applications, Thora Maltais May 2011

Incorporation Of Novel Diphosphines Into Polymer Structure For Light Absorption And Emission Applications, Thora Maltais

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In today's society, there is a constant need for the development and production of new and improved technology, especially in the development of light emitting diodes for screens in electronic devices, and photovoltaic cells as sources for alternative energy. New insights for the development of such technology can be elucidated through the incorporation of chromophoric diphosphines into phosphonium and platinum(II) polymer frameworks. From diphosphine incorporation, it will be shown that polymer properties can be enhanced for such applications by invoking phosphorescence, and providing a modular platform for generating multilayer polymer films that provide intriguing energy transfer capabilities in the visible …


Assessment Of Conceptual Understanding Of Atomic Structure, Covalent Bonding, And Bond Energy, Alma Gonzales May 2011

Assessment Of Conceptual Understanding Of Atomic Structure, Covalent Bonding, And Bond Energy, Alma Gonzales

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This research work relied upon the importance of conceptual understanding to meaningful learning. Conceptual understanding is strongly influenced by students' prior knowledge (1). Many of these ideas pose strong barriers to deeper understanding and are called misconceptions since they are inconsistent or in conflict with generally accepted scientific facts (2). Thus, it is beneficial for instructors to initially elicit students' conceptual understanding in order to properly address student's misconceptions during the learning process. However, results are very dependent on the instrument used to elicit conceptual understanding (3). The most commonly used tools are summative assessments or achievement tests (4). They …


Uranyl Reactions With Dithionite, L-Ascorbic Acid, And Supported Nanosized Zero-Valent Iron, Shanna Estes Jan 2011

Uranyl Reactions With Dithionite, L-Ascorbic Acid, And Supported Nanosized Zero-Valent Iron, Shanna Estes

All Theses

This work examined several reductants for remediation of low pH aqueous uranium contamination by reductive precipitation. Reductants included sodium dithionite, L-ascorbic acid, and nanosized zero-valent iron (nZVI). Additionally, the reductive capacity of nZVI successfully entrapped within a silicate matrix (cryogel) was also examined. This supported nZVI is expected to increase nZVI stability in the subsurface, and to provide a convenient in situ delivery mechanism for other remediation systems which may combine entrapped reductant and catalyst.
Fluorescence and absorbance spectroscopy were used to investigate the interaction between hexavalent uranium (U(VI), uranyl) and both sodium dithionite and L-ascorbic acid at pH 2. …