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Full-Text Articles in Physical Sciences and Mathematics
Computational Investigations Of The Structure And Spectroscopy Of Small Biomolecules In The Gas Phase, Zachary Michael Smith
Computational Investigations Of The Structure And Spectroscopy Of Small Biomolecules In The Gas Phase, Zachary Michael Smith
Dissertations, Theses, and Masters Projects
Small biomolecule systems were interrogated using infrared multiple photon dissociation (IRMPD) action spectroscopy and corresponding quantum chemical calculations with a particular focus on peptide fragmentation and protonation site preference. b2+ and b3+ fragment ions with a terminal lysine homolog residue were investigated using IRMPD in the fingerprint region (1000 cm-1 – 2000 cm-1) and a variety of computational methods. We present the first spectroscopic confirmation of b-ion formation with a lactam structure. Infrared spectra for b2+ fragment system indicate the presence of a mixture of structures, though final determination will require further investigation. The b3+ fragment ion infrared spectra show …
Asymmetric Hillslope Erosion Following Wildfire In Fourmile Canyon, Colorado, Edward R. Abrahams, James M. Kaste, William Ouimet, David P. Dethier
Asymmetric Hillslope Erosion Following Wildfire In Fourmile Canyon, Colorado, Edward R. Abrahams, James M. Kaste, William Ouimet, David P. Dethier
Arts & Sciences Articles
Infrequent, high-magnitude events cause a disproportionate amount of sediment transport on steep hillslopes, but few quantitative data are available that capture these processes. Here we study the influence of wildfire and hillslope aspect on soil erosion in Fourmile Canyon, Colorado. This region experienced the Fourmile Fire of 2010, strong summer convective storms in 2011 and 2012, and extreme flooding in September 2013. We sampled soils shortly after these events and use fallout radionuclides to trace erosion on polar- and equatorial-facing burned slopes and on a polar-facing unburned slope. Because these radionuclides are concentrated in the upper decimeter of soil, soil …
A Terbium Chlorobismuthate(Iii) Double Salt: Synthesis, Structure, And Photophysical Properties, John C. Ahern, Aaron D. Nicholas, Andrew W. Kelly, Benny Chan, Robert D. Pike, Howard Patterson
A Terbium Chlorobismuthate(Iii) Double Salt: Synthesis, Structure, And Photophysical Properties, John C. Ahern, Aaron D. Nicholas, Andrew W. Kelly, Benny Chan, Robert D. Pike, Howard Patterson
Arts & Sciences Articles
We report on the structure and luminescence of a double salt trivalent rare earth ion acceptor, Tb3+, with octahedral [BiCl6]3– donor clusters. The novel TbBiCl6·14H2O (1) was prepared from aqueous BiOCl and TbCl3·6H2O. The crystal structure of compound 1 exhibits isolated [BiCl6]3– and [Tb(OH2)8]3+ clusters. Luminescence data show energy transfer from octahedral chlorobismuthate(III) clusters to rare earth metal ions. Density Functional Theory (DFT) calculations show distinctly different emission pathways at high and low excitation energies.
Probing Molecular Dynamics With Hyperpolarized Ultrafast Laplace Nmr Using A Low-Field, Single-Sided Magnet, Jared N. King, Alfredo Fallorina, Justin Yu, Et Al., Tyler K. Meldrum
Probing Molecular Dynamics With Hyperpolarized Ultrafast Laplace Nmr Using A Low-Field, Single-Sided Magnet, Jared N. King, Alfredo Fallorina, Justin Yu, Et Al., Tyler K. Meldrum
Arts & Sciences Articles
Laplace NMR (LNMR) offers deep insights on diffusional and rotational motion of molecules. The so-called “ultrafast” approach, based on spatial data encoding, enables one to carry out a multidimensional LNMR experiment in a single scan, providing from 10 to 1000-fold acceleration of the experiment. Here, we demonstrate the feasibility of ultrafast diffusion–T2 relaxation correlation (D–T2) measurements with a mobile, low-field, relatively low-cost, single-sided NMR magnet. We show that the method can probe a broad range of diffusion coefficients (at least from 10−8 to 10−12 m2 s−1) and reveal multiple components of fluids in heterogeneous …
Iron Polypyridyl Catalysts Assembled On Metal Oxide Semiconductors For Heterogeneous Photocatalytic Hydrogen Generation, Nicholas Race
Iron Polypyridyl Catalysts Assembled On Metal Oxide Semiconductors For Heterogeneous Photocatalytic Hydrogen Generation, Nicholas Race
Dissertations, Theses, and Masters Projects
Artificial Photosynthesis (AP) provides a promising method for the conversion of solar energy to chemical fuel in the form of H2 and O2. Development of heterogeneous systems in which H2 evolution catalysts are immobilized on metal oxide semiconductors is imperative for the large-scale implementation of AP systems. This research focuses on the immobilization of an active H2 evolution catalyst on large band gap semiconductors for the development and optimization of a highly active photocatalytic H2 generation system.
Surface-Enhanced Raman Spectroscopy Studies Of Organic Dyes For Art Conservation And Ph Sensing Applications, Shelle Nicholle Butler
Surface-Enhanced Raman Spectroscopy Studies Of Organic Dyes For Art Conservation And Ph Sensing Applications, Shelle Nicholle Butler
Dissertations, Theses, and Masters Projects
Surface-enhanced Raman scattering (SERS) spectroscopy is a powerful analytical technique with widespread applications. In this work, SERS applications in the realms of art conservation and biosensing are reviewed. First, the theory of this unambiguous and ultrasensitive technique is explained. Next, a review of the pedagogical journey in art conservation research through the lenses of undergraduates is offered in Chapter 2, a chapter recently submitted to the American Chemical Society. Finally, an investigation in biosensing SERS is explored with developing a SERS pH sensitive probe while offering new insight into SERS capabilities and the relationship between analyte and nanoparticle.
Ratiometric Fluorescent Sensors In Aqueous Environments, Matthew August Mccarron
Ratiometric Fluorescent Sensors In Aqueous Environments, Matthew August Mccarron
Dissertations, Theses, and Masters Projects
Conjugated polymer nanoparticles (CPN) doped with a mercury sensitive dye are able to detect ion concentrations as low as a parts-per-billion within an aqueous environment. Select forms of spirolatam rhodamine dye are capable of selectively undergoing a ring-opening reaction in response to Hg2+ ions. The initial closed form presents as a colorless, non-fluorescent, compound while the opened form results in a colored and highly fluorescent form. The CPNs are also fluorescent, yet at a lower wavelength and can transfer of their energy into the dye molecules via Förster resonance energy transfer. The dye’s reaction with Hg2+ goes unhindered by the …
Effect Of Pigment Volume Concentration On Physical And Chemical Properties Of Acrylic Emulsion Paints Assessed Using Single-Sided Nmr, Mary Therese Rooney
Effect Of Pigment Volume Concentration On Physical And Chemical Properties Of Acrylic Emulsion Paints Assessed Using Single-Sided Nmr, Mary Therese Rooney
Dissertations, Theses, and Masters Projects
Acrylic emulsion paint is one of the most common media employed by 20th century painters. Since early acrylic paintings have begun to require the attention of conservators, scientists are working to characterize the properties of these paints to facilitate conservation efforts. In this study, we report an investigation of the physical and chemical properties of acrylic emulsion paints using single-sided NMR in conjunction with gloss measurements and scanning electron microscopy coupled with energy dispersive spectrometry. Combining the data from these techniques gives insight into pigment-binder interactions and the acrylic curing process, showing that as pigment concentration is increased in paints, …
Crystal Structure And Computational Analysis Of A Two-Dimensional Coordination Polymer, Bii3(Dppeo2)3/2, Andrew W. Kelly, Amelia M. Wheaton, Aaron D. Nicholas, Howard H. Patterson, Robert D. Pike
Crystal Structure And Computational Analysis Of A Two-Dimensional Coordination Polymer, Bii3(Dppeo2)3/2, Andrew W. Kelly, Amelia M. Wheaton, Aaron D. Nicholas, Howard H. Patterson, Robert D. Pike
Arts & Sciences Articles
Catena-poly[fac-triiodobismuth(III)-tris-(µ-ethane-1,2-diylbis(diphenylphosphane oxide-κ2O,O′))], a 2-D sheet network of BiI3 was synthesized from BiI3 and ethane-1,2-diylbis(diphenylphosphane oxide) (DppeO2) in tetrahydrofuran. The crystal structure revealed a trigonal structure with three-fold symmetry at Bi. Bismuth centers show fac-BiI3O3 coordination, with Bi–I = 2.9416(2) Å and Bi–O = 2.4583(17) Å. The I–Bi–I and O–Bi–O angles (95.520(7)° and 79.04(6)°, respectively) indicate trigonal distortion in the Bi octahedron. Bridging DppeO2 ligands centered on inversion centers give rise to a 2-D sheet polymer. The 8.3 Å thick sheets consist of three layers in a sandwich structure. The outer layers are composed of phenyl rings and …
Development Of A One Pot [4+2]/R[4+2] 2-Pyridone Synthesis And The Fluorescence Of 2-Pyridone Azafluorenones, Nicholas Angello
Development Of A One Pot [4+2]/R[4+2] 2-Pyridone Synthesis And The Fluorescence Of 2-Pyridone Azafluorenones, Nicholas Angello
Dissertations, Theses, and Masters Projects
We report the concise synthesis of several tricyclic 2-pyridones via a one pot sequence involving an aldol condensation, alkene isomerization, intramolecular Diels-Alder cycloaddition, and selective retro-Diels-Alder cycloreversion. The starting materials are synthesized in one step from cheap and commercially available precursors. The intermediate [2.2.2]diazabicycloalkene cycloadducts can be isolated. The retro-Diels-Alder occurs at easily accessible temperatures due to base acceleration. Simple derivatization of the tricyclic products afforded azafluorenones with unprecedented fluorescent activity due to the pyridone motif.
Monitoring Infection Of E. Coli By Bacteriophage T7 Through Mass Spectrometry-Based Proteomics, Amy Swayne Schienschang
Monitoring Infection Of E. Coli By Bacteriophage T7 Through Mass Spectrometry-Based Proteomics, Amy Swayne Schienschang
Dissertations, Theses, and Masters Projects
Mass spectrometry-based proteomics has become an important and versatile tool in analytical chemistry, making sense of complex biological samples and shedding light on the intricate proteomes of living organisms. Bottom-up proteomics studies are used to elucidate the changes in gene expression of bacteriophage T7 over the course of infection of Escherichia coli. E. coli cultures were infected with T7, sampled over time, and proteins were isolated and enzymatically digested. Nanoflow liquid chromatography combined with tandem mass spectrometry was used to detect proteolytic peptides and identify host and phage proteins. Generally, phage proteins were detected on a time scale fitting the …
Radiation Shielding Bricks For Mars Using Martian Regolith Simulant And Hydrogen-Rich Polymers, Sara Sargent
Radiation Shielding Bricks For Mars Using Martian Regolith Simulant And Hydrogen-Rich Polymers, Sara Sargent
Dissertations, Theses, and Masters Projects
Radiation shielding materials are an essential component of long-term space travel and habitation. The mission to Mars will require a radiation shielding material that can be produced on Mars through energy and cost-efficient means. in this study, Martian regolith simulant and hydrogen-rich polymers are used to create a radiation shielding material in the form of bricks. The bricks are capable of shielding against galactic cosmic radiation on Mars. There are three methods in which the bricks were formed: 1) a heated press, 2) a microwave oven in a CO2 atmosphere, and 3) a vacuum oven with a low CO2 pressure. …