Biological and Chemical Physics Commons^™

Novel Materials For Use In Homeland Security Research, Jason Osgood Ewen Young

Masters Theses & Specialist Projects

Organometallic pyridazines and compounds derived from them have been of interest in polymer research due to their atypical environmental stability (as compared to other non-aromatic organic semiconductors) as well as their conductivity. The off-metal synthesis and characterization of several pyridazyl thallium, manganese, and rhenium complexes, beginning with fulvenes 1,2- C5H3(COHR)(COR), are reported here. The diacyl fulvenes were treated with hydrazine hydrate to ring close to pyridazines. Next, the pyridazines were converted to their respective thallium salts through treatment with thallium (I) ethoxide. Lastly, the salts were transmetallated into the respective rhenium or manganese complexes through treatment with ...

Study Of Ultrashort Laser-Pulse Induced Ripples Formed At The Interface Of Silicon-Dioxide On Silicon, Bing Liu

Open Access Dissertations and Theses

In this thesis, the ripple formation at the interface of SiO2 and Si were studied in a systematic fashion by irradiating the SiO2-Si samples with ultrashort laser pulses under a broad variety of experimental conditions. They consist of di↵erent irradiating laser wavelengths, incident laser energies, translation speeds, translation directions, spot sizes of the laser beam, as well as oxide thicknesses. The ripples produced by laser irradiation are examined using various microscopy techniques in order to characterize their surface morphology, detailed structures, crystalline properties, and so on. For the experiments carried out at ! = 800 nm, the ripples formed on the ...

Nuclear Magnetic Resonance Studies Of Sodiumaluminohexahydride (Na3alh6), Tim J. Ellis-Caleo

Undergraduate Research Symposium

Many applications of modern physics require the investigator to understand the behavior of specific atoms in compounds. The behavior and structure of molecules such as sodiumaluminohexahydride (Na3AlH6) is relevant to the field of hydrogen storage [1]. In this study, we used nuclear magnetic resonance to examine the behavior of sodium, aluminum and hydrogen atoms in the compound sodiumaluminohexahydride. Sodiumaluminohexahydride consists of a covalently bonded AlH6 anion that forms an ionic bond with a sodium cation [2]. Particularly, we investigated the atomic motion at various temperatures by looking at the motional averaging of the atoms as a function of temperature from ...

Second Moment Analysis Of Sodium Aluminohexahydride (Na3alh6) Nmr, Tim J. Ellis-Caleo

Undergraduate Research Symposium

Sodium aluminohexahydride (Na3AlH6) is a promising candidate for reversible hydrogen storage. Understanding the motion of individual atoms within the crystalline lattice is a key challenge of studying hydrogen storage candidates. This molecule is formed by sodium cations and an aluminohexahydride (AlH6-) anion cluster. We examined the relative widths of the lineshapes over the temperature range 23oC to 240oC and noticed significant narrowing, allowing us to conclude that some of the nuclei are moving. It is important to understand not only which nuclei are moving, but also how they are moving. In this case, second moment calculations can be performed to ...

Resiliency To Bistability In The Neurons From The Pre-Bötzinger Complex, Treadwell D. Singfield Ii

Georgia State Undergraduate Research Conference

No abstract provided.

Raman Spectroscopic Analysis Of Human Skin Tissue Sections Ex-Vivo: Evaluation Of The Effects Of Tissue Processing And Dewaxing, Syed Mehmood Ali, Franck Bonnier, Ali Tfayli, Helen Lambkin, Kathleen Flynn, Vincent Mcdonagh, Claragh Healy, Thomas Lee, Fiona Lyng, Hugh Byrne

Articles

Raman spectroscopy coupled with K-means clustering analysis (KMCA) is employed to elucidate the biochemical structure of human skin tissue sections, and the effects of tissue processing. Both hand and thigh sections of human cadavers were analysed in their unprocessed and formalin fixed paraffin processed (FFPP) and subsequently dewaxed forms. In unprocessed sections, KMCA reveals clear differentiation of the stratum corneum, intermediate underlying epithelium and dermal layers for sections from both anatomical sites. The stratum corneum is seen to be relatively rich in lipidic content; the spectrum of the subjacent layers is strongly influenced by the presence of melanin, while that ...

Fast Absolute Quantification Of In Vivo Water And Fat Content With Magnetic Resonance Imaging, Yifan Cui

Electronic Thesis and Dissertation Repository

Quantitative water fat imaging offers a non-invasive method for monitoring and staging diseases associated with changes in either water or fat content in tissue. In this work absolute water and fat mass density measurement with in vivo Magnetic Resonance Imaging (MRI) is demonstrated. T₁ independent, T₂^* corrected chemical shift based water-fat separated images are acquired. By placing a phantom with known mass density in the field of view for signal intensity calibration, absolute water or fat mass density can be computed, assuming the B₁⁺ (transmit) and B₁^- (receive) fields can be measured. Phantom experiments with known ...

Angular And Dynamical Properties In Resonant Inelastic X-Ray Scattering: Case Study Of Chlorine-Containing Molecules, Renaud Guillemin, Wayne C. Stolte, Loic Journel, Stephane Carniato, Maria Novella Piancastelli, Dennis W. Lindle, Marc Simon

Faculty Publications (Chem)

Polarization-dependent resonant inelastic x-ray scattering (RIXS) has been shown to be a probe of molecular-field effects on the electronic structure of isolated molecules. In this experimental analysis we explain the linear dichroism observed in Cl 2p polarized RIXS following Cl 1s excitation of a series of chlorofluoromethanes (CF3Cl, CF2Cl2, CFCl3, and CCl4) as due to molecular-field effects, including singlet-triplet exchange. We present an approach to extract directly the 2p inner-shell electronic state populations from the experimental measurements. Using the angular properties of the measured KV emission we also are able to determine the value of the polarization anisotropy parameter βp ...

Using The Totally Asymmetric Exclusion Process As A Model For Protein Translation, Pak Lam (Philip) Lee

Open Access Dissertations and Theses

This thesis details the development of a kinetic model of translation which takes into account codon usage. The process of translation involves ribosomes decoding a sequence of codons to produce a protein. Codon usage is important in the kinetics of translation since experiments have shown that codons are processed at different rates. Codons which code for the same amino acid appear with unequal frequencies and certain synonymous codons are preferred by high expression genes. The relationship between translational efficiency and codon adaptation is explored in this thesis.

We use a simple physics model called the totally asymmetric exclusion process (TASEP ...

Modeling Hydrogen-Bonding In Diblock Copolymer/Homopolymer Blends, Ashkan Dehghan Kooshkghazi

Open Access Dissertations and Theses

The phase behavior of AB diblock copolymers mixed with C homopolymers (AB/C), in which A and C are capable of forming hydrogen-bonds, is examined using self-consistent field theory. The study focuses on the modeling of hydrogen-bonding in polymers. Specifically, we examine two models for the formation of hydrogen-bonds between polymer chains. The first commonly used model assumes a large attractive interaction parameter between the A/C monomers. This model reproduces correct phase transition sequences as compared with experiments, but it fails to correctly describe the change of lamellar spacing induced by the addition of the C homopolymers. The second ...

The Origin Of Life By Means Of Autocatalytic Sets Of Biopolymers, Meng Wu

Open Access Dissertations and Theses

A key problem in the origin of life is to understand how an autocatalytic, self-replicating biopolymer system may have originated from a non-living chemical system. This thesis presents mathematical and computational models that address this issue. We consider a reaction system in which monomers (nucleotides) and polymers (RNAs) can be formed by chemical reactions at a slow spontaneous rate, and can also be formed at a high rate by catalysis, if polymer catalysts (ribozymes) are present. The system has two steady states: a ‘dead’ state with a low concentration of ribozymes and a ‘living’ state with a high concentration of ...

Molecular Dynamics Studies Of Water Flow In Carbon Nanotubes, Alexander D. Marshall

Electronic Thesis and Dissertation Repository

We present classical molecular dynamics (MD) simulations providing insight into the behaviour of water. We focus on confined water, the properties of which are often significantly different from the properties of bulk water.

First, we performed several simulations investigating the handling of long-range interactions in GROMACS [1], a MD simulation package. Selection of simulation protocols such as handling of long-range interactions is often overlooked, sometimes to the significant detriment of the final result [2, 3, 4]. Ensuring that the chosen simulation protocols are appropriate is a critical step in computer simulation.

Second, we performed MD simulations where water flowed between ...

Structure And Dynamics Of Model Systems: From Ferrofluids To Brain Membranes, Matthew A. Barrett

Open Access Dissertations and Theses

Soft condensed matter systems are a very diverse and challenging subject to study. To understand the complex macro-properties of such systems one approach is to characterize the microscopic structure and dynamics. A powerful technique for determining micro and nanoscale properties is scattering of radiation sources. Light, electron and neutron scattering techniques provide insight into the complicated molecular structures and the processes happening on these small scales.

We have used neutron and x-ray scattering techniques to determine structural and dynamical information from two different types of soft condensed matter systems. The microscopic nature of a cobalt magnetic fluid was studied using ...