Computational and Experimental Investigations Concerning Rare Gas and DPAL Lasers and a Relaxation Kinetics Investigation of the Br\u3csub\u3e2\u3c/sub\u3e + 2NO = 2BrNO Equilibrium

This research contains four different research projects, the first an educational project introducing hydrogen bromide and deuterium bromide (HBr/DBr) and carbon monoxide (CO) as viable options for infrared vibration-rotation spectroscopy at 0.125 cm-1 or 0.5 cm-1 resolution in the teaching laboratory. The second project involved determining the spectral shifts of lanthanide fibers for diode-pumped alkali laser (DPAL) applications. Spectral shifts of lanthanides were determined using UV-VIS-NIR absorbance spectroscopy and laser-induced fluorescence (LIF). The third project entailed computing Ar* atomic energy levels and the potential energy curves of Ar*+He laser systems arising from 3p54s1 and 3p54p1 Ar* electronic configurations using ab initio theory. The final project of this research determined rate coefficients and the equilibrium constant of the formation of nitrosyl bromide (BrNO) using relaxation kinetics. Integrated solution of the relaxation rate equation and third-order integrated rate law methodologies produced final values of kf = 1.50(6) x 10-5 torr-2s-1, kr = 5.8(8) x 10-5 torr-1s-1, and Keq = 0.26(3) torr-1, agreeing with literature within uncertainty

Laser-induced Fluorescence (lif) Of Jet-cooled Smo

The chemi-ionization reactions of atomic lanthanides M + O $\rightarrow$ MO$^{+}$ + \emph{e}$^{-}$ are currently being investigated as a method to artificially increase the localized electron density in the ionosphere for uniform radio wave propagation. Recent experiments involving the release of atomic samarium (Sm) into the upper atmosphere have resulted in the production of a cloud with blue and red emissions[1]. Spectroscopic characterization of both SmO and its cation SmO$^{+}$ is required to accurately determine the fraction of SmO$^{+}$ present in the release cloud. While the low-lying states of SmO have been previously spectroscopically characterized, the analysis was hindered due to the production of SmO under high temperature conditions[2,3]. In this experiment, SmO was jet-cooled to 70K and laser-induced fluorescence (LIF) spectra were obtained over the range from 15,000-16,000 \wn. Dispersed laser-induced fluorescence (DLIF) spectra were also obtained for vibrational characterization of the ground and low-lying states. Fluorescence lifetime measurements have been used to determine Einstein \emph{A} coefficients. Data and analysis of ground and low-lying excited states of SmO will be presented. $\newline$ $\newline$ \indent[1] Ard, S.G. et al. J. Chem. Phys.2015, 143, 204303.$\newline$ \indent[2] Hannigan, M. C. J. Mol. Spec. 1983, 99, 235-238.$\newline$ \indent[3] Linton, C. et al. J. Mol. Spec. 1987, 126, 370-392

LASER-INDUCED FLUORESCENCE (LIF) OF JET-COOLED THORIUM NITRIDE (ThN)

Due to their higher melting point and metal ion density compared to their oxide counterparts, actinide nitrides are promising candidates for nuclear fission sources in nuclear reactors. While thorium mononitride (ThN) is a possible fission source in thorium-based reactors, few studies on ThN have been conducted. Previous ThN studies have characterized gas-phase rovibronic transitions through resonance-enhanced multiphoton ionization (REMPI) and laser-induced fluorescence (LIF) spectroscopic methods[1]. These uncalibrated low-resolution survey spectra, however, were mostly unanalyzed. A calibrated, higher resolution spectrum was recorded for one vibronic band ([20.9]1.5-X$^{2}$$\Sigma$$^{+}$) and spectroscopic constants were reported for the ground state and the electronically excited state[1]. More recently, a second band ([18.0]1.5-X$^{2}$$\Sigma$$^{+}$) has been observed at high-resolution and used to examine the fine and hyperfine structure of ThN(X)[2]. In the present study, ThN was jet-cooled to approximately 100K and LIF spectra were recorded over the range 20,000-21,300 cm$^{-1}$. A tellurium (Te$_{2}$) cell was heated to 650$^{\circ}$ C and its absorbance spectrum was used for spectral calibration. Data and analyses of the observed ground state and excited states of ThN will be presented. [1] M.C. Heaven, B.J. Barker, I.O. Antonov, J. Phys. Chem. A, 118 (2014) 10867-10881. [2] A. T. Le, S. Nakhate, T. Nguyen, T. C. Steimle, M. C. Heaven, J. Chem. Phys., submitte

A preliminary longitudinal study of white matter alteration in cocaine use disorder subjects

Background Previous diffusion tensor imaging (DTI) studies have consistently shown that subjects with cocaine use disorder (CocUD) had altered white matter microstructure in the corpus callosum. It is believed that these alterations are due to preexisting factors, chronic cocaine use, or both. However, there is no published longitudinal DTI study on human cocaine users yet which could shed light on the relationship between cocaine use and DTI findings. Methods This study used a longitudinal design and DTI to test if the white matter microstructure shows quicker alteration in CocUD subjects than controls. DTI data were acquired from eleven CocUD subjects who participated a treatment study and eleven non-drug-using controls at baseline (Scan 1) and after ten weeks (Scan 2). The baseline fractional anisotropy (FA), a general measure of white matter microstucture, and the change in FA (ΔFA, equals Scan 1 FA minus Scan 2 FA) were both compared between groups. Results The two groups did not show a difference in FA at baseline. The CocUD subjects had significantly greater ΔFA than the controls in the left splenium of the corpus callosum. In CocUD subjects, greater ΔFA in this region was associated with shorter lifetime cocaine use and greater number of positive cocaine urine samples collected during the treatment. Conclusion The finding in the left splenium is consistent with previous animal studies and provide indirect evidence about the effects of chronic cocaine use on white matter alterations. The subject sample size is small, therefore the results should be treated as preliminary

EXPANDED CHOICES FOR VIBRATION-ROTATION SPECTROSCOPY IN THE PHYSICAL CHEMISTRY TEACHING LABORATORY

Many third-year physical chemistry laboratory students in the US analyze the vibration-rotation spectrum of HCl in support of lecture concepts in quantum theory and molecular spectroscopy. Contemporary students in physical chemistry teaching laboratories increasingly have access to FTIR spectrometers with 1/8th wn resolution, which allows for expanded choices of molecules for vibration-rotation spectroscopy. Here we present the case for choosing HBr/DBr for such a study, where the 1/8th wn resolution enables the bromine isotopic lines to be resolved. Vibration-rotation lines from the fundamental and first-overtone bands of four hydrogen bromide isotopomers are combined in a global analysis to determine molecular spectroscopic constants. Sample production, spectral appearance, analysis and results will be presented for various resolutions commonly available in teaching laboratories

LASER INDUCED FLUORESCENCE (LIF) SPECTROSCOPY OF JET COOLED ThO

Knowledge of actinide bonding is essential for nuclear energy and reactor applications, including nuclear waste treatment. Due to its relatively simple electronic structure, thorium oxide (ThO) is an ideal molecule to study actinide bonding. Previous studies have reported visible and near UV band systems that were recorded under high temperature conditions. Spectral congestion significantly complicated the analyses of these data. In the present work we have examined ThO bands under conditions where jet cooling was used to reduce the rotational temperature to approximately 90 K. LIF spectra were recorded over the range 18,000-19,800 \wn. Several new vibronic bands have been characterized. Some extend the data range for known electronic transitions, while others belong to electronic states that have not been reported previously. Analysis of these data and models for the electronically excited states of ThO will be presented

Physical and Social Contexts of Physical Activities Among Adolescent Girls

Background: With limited opportunities for physical activity during school hours, it is important to understand the contexts of physical activities done outside of school time. Given the importance of physical and social aspects of environments, the purpose of this study was to describe where and with whom girls participate in physical activities outside of school. Methods: Participants were 1925 sixth-grade girls in the Trial of Activity for Adolescent Girls (TAAG). At baseline, they completed a 3-day physical activity recall (3DPAR), reporting the main activity performed during 30-minute intervals and the physical and social contexts of physical activities. Results: The most frequently reported physical activities done outside of school time were house chores, walking (for transportation or exercise), dance, basketball, playing with younger children, and running or jogging. The most common location for these activities was at home or in the neighborhood. With the exception of household chores, these activities were typically done with at least one other person. Conclusions: Interventions that promote physical activities that can be done at or around home or developing supportive social networks for physical activity would be consistent with the current physical activity contexts of adolescent girls

Increased Orbitofrontal Brain Activation after Administration of a Selective Adenosine A2A Antagonist in Cocaine Dependent Subjects

Background: Positron Emission Tomography imaging studies provide evidence of reduced dopamine function in cocaine dependent subjects in the striatum, which is correlated with prefrontal cortical glucose metabolism, particularly in the orbitofrontal cortex. However, whether enhancement of dopamine in the striatum in cocaine dependent subjects would be associated with changes in prefrontal cortical brain activation is unknown. One novel class of medications that enhance dopamine function via heteromer formation with dopamine receptors in the striatum is the selective adenosine A2A receptor antagonists. This study sought to determine the effects administration of the selective adenosine A2A receptor antagonist SYN115 on brain function in cocaine dependent subjects. Methodology/Principle Findings: Twelve cocaine dependent subjects underwent two fMRI scans (one after a dose of placebo and one after a dose of 100 mg of SYN115) while performing a working memory task with three levels of difficulty (3, 5, and 7 digits). fMRI results showed that for 7-digit working memory activation there was significantly greater activation from SYN115 compared to placebo in portions of left (L) lateral orbitofrontal cortex, L insula, and L superior and middle temporal pole. Conclusion/Significance: These findings are consistent with enhanced dopamine function in the striatum in cocaine dependent subjects via blockade of adenosine A2A receptors producing increased brain activation in the orbitofrontal cortex and other cortical regions. This suggests that at least some of the changes in brain activation in prefrontal cortical regions in cocaine dependent subjects may be related to altered striatal dopamine function, and that enhancement of dopamine function via adenosine A2A receptor blockade could be explored further for amelioration of neurobehavioral deficits associated with chronic cocaine use

BBF RFC 105: The Intein standard - a universal way to modify proteins after translation

This Request for Comments (RFC) proposes a new standard that allows for easy and flexible cloning of intein constructs and thus makes this technology accessible to the synthetic biology community