Neighborhood fast food restaurants and fast food consumption: A national study

<p>Abstract</p> <p>Background</p> <p>Recent studies suggest that neighborhood fast food restaurant availability is related to greater obesity, yet few studies have investigated whether neighborhood fast food restaurant availability promotes fast food consumption. Our aim was to estimate the effect of neighborhood fast food availability on frequency of fast food consumption in a national sample of young adults, a population at high risk for obesity.</p> <p>Methods</p> <p>We used national data from U.S. young adults enrolled in wave III (2001-02; ages 18-28) of the National Longitudinal Study of Adolescent Health (n = 13,150). Urbanicity-stratified multivariate negative binomial regression models were used to examine cross-sectional associations between neighborhood fast food availability and individual-level self-reported fast food consumption frequency, controlling for individual and neighborhood characteristics.</p> <p>Results</p> <p>In adjusted analysis, fast food availability was not associated with weekly frequency of fast food consumption in non-urban or low- or high-density urban areas.</p> <p>Conclusions</p> <p>Policies aiming to reduce neighborhood availability as a means to reduce fast food consumption among young adults may be unsuccessful. Consideration of fast food outlets near school or workplace locations, factors specific to more or less urban settings, and the role of individual lifestyle attitudes and preferences are needed in future research.</p

Volume 01

Introduction from Dean Dr. Charles Ross Three Decades of Digging: Undergraduate Archeology at Longwood by Jessica Fields and Stephanie Neeley Interactions of Allelopathy and Heat Stress in Plants by Derek W. Hambright and Mary E. Lehman Inertial Electrostatic Confinement D-D Fusion Device: Construction and Simulation by Andrew R. Grzankowski Shackled Nim by Zachary Johnson Development of GC-MS and Chemometric Methods for the Analysis of Accelerants in Arson Cases by Boone M. Prentice A Comparison of Image Analysis Methods in cDNA Microarrays by Ashley M. Swandby Perceived Sexual Activity of Short and Long-Term Relationships by Victoria Morgan and Katie Williamson Elderly Male Communication by Kristine G. Bender Three Poems: “Adam and Eve and an Orange Tree”, “The Name of Everything Before Dying”, and “The ‘Poet Voice’” by Katelyn N. Romaine There\u27s Nothing Like Dancing, After All : Marriage and Gender in the Dance Scenes of Jane Austen\u27s Novels by D. Nicole Swann Two Poems: “Age Nine with Mother” and “The Apple That Crawls Away From the Tree” by Jessica Fox Untitled by Mike McAteer Room 9 by Alex Grabiec Two Photographs: “Gracie” and “Emily” by Laura Nodtvedt Bowling Lanes Night by Nick Costa Two Paintings: “Can and Kettle” and “Scarecrow” by Rachel Wolfe Exploring Henrik Ibsen\u27s “Perr Gynt” by Zack Dalton Creative Writing Scholarship at Longwood University Music Scholarship at Longwood – Senior Recital Arianne K. Burrus Longwood University Theater – Peer Gyn

Mass spectrometry instrumentation and ion/ion reaction method development for the fundamental analysis of gas phase biomolecules

Mass spectrometry (MS) and tandem mass spectrometry (MSn) approaches play vital roles in the molecular analysis of many different types of analytes (e.g., proteins, peptides, etc.). The typical molecular mass spectrometry experiment involves making/sampling ions, probing ions, and transmitting/measuring ions. While the work described herein covers a broad range of technical mass spectrometry instrumentation and experimentation topics on each of these three main segments, the fundamental study of physical and chemical ionic behaviors is a common theme throughout. A technique which has been previously developed to manipulate droplets generated via electrospray ionization (ESI) during the ionization process (viz. the making/sampling phase) was quantified using a mathematical model. This technique involves the controlled introduction of volatile acidic and basic reagents into the interface region of the mass spectrometer where electrospray droplets are undergoing desolvation on the sub-millisecond time scale. Quantitative pH results from this model show good correlation with experimental results. Several projects were also completed involving ion transmission phases. One such projected was the construction and implementation of a miniature ion funnel interface, based off of the design reported by Julian et al. This interface is designed to increase the transmission efficiency (~100x) of ions generated via atmospheric ionization techniques into the high vacuum region of the mass spectrometer. Once the ions are inside the mass spectrometer, it was discovered that introducing a monopolar DC field during a number steps in a typical 3-D ion trap MS experiments could result in significant enhancements in instrument performance (e.g., ion accumulation efficiency, ion/ion reaction control, mass analysis). The final phase of a mass spectrometry experiment involves measuring and detecting the ions. A novel method for performing mass analysis in a 3-D ion trap was developed and characterized which involves scanning the quadrupolar DC potential applied to the ion trap while holding the RF potential. This `downscan\u27 can offer some advantages over the traditional RF scan for ions of high m/z values, including a larger scanable mass range as well as the opportunity for improved resolution at high mass. Perhaps more chemically interesting is the work herein devoted to the development and characterization of several different methods to structurally interrogate ions (viz. the probing phase). The design and development of two ion activation approaches using a 3-D ion trap mass spectrometer, dipolar direct current collision induced dissociation (DDC CID) and photodissociation (PD), have been other major areas of research. Interesting characteristics of DDC CID, relative to the conventional single-frequency resonance excitation approach commonly employed, are its non-resonant or broad-band nature and the fact that ions of all m/z values are activated simultaneously. Key to the information derived from activation techniques such as the one mentioned above and from reactions performed inside the mass spectrometer is the ion type. Our research group is actively pursuing targeted chemical derivatization techniques that can be performed via ion/ion reactions ( viz. reactions involving a cation and anion) in the gas-phase as part of MSn workflows for biopolymer characterization. Here, this targeted gas-phase chemistry is extended to analytes containing carboxylic acid groups and carboxylate groups using carbodiimide and fixed charge ammonium reagents, respectively. In the spirit of exploring a wider range of chemistries, studies have been conducted involving non-covalently-bound cluster ions as reagent ion types. Relatively stable non-covalent cluster-type ion complexes have been used as multi-functional reagents in ion/ion reactions. This type of methodology allows for multiple covalent modifications to be achieved in a single ion/ion encounter and at the `cost\u27 of only a single analyte charge. These experiments spurred further investigation into the surprisingly gas phase reactive behavior of arginine residues cationized with sodium towards sulfo-NHS ester reagents. Additionally, another area of research aims to implement a means to cool a 3-D ion trap so as to extend the lifetimes of solvated ions, which are typically short lived under ambient MS conditions. This instrumentation opens up numerous avenues for both fundamental and applicative studies of a wide variety of different chemical reactions, allowing the study of solution-phase-limited reactions using the inherent benefits of mass spectrometric analysis. This instrumentation design currently involves the use of copper blocks connected to the end-cap electrodes that are be cooled via their attachment to a custom built, in-vacuum liquid nitrogen dewar

Ion/Ion Reactions with “Onium” Reagents: An Approach for the Gas-phase Transfer of Organic Cations to Multiply-Charged Anions

xvii,; 246 hlm,; 21 c

Standard Reticle Slide To Objectively Evaluate Spatial Resolution and Instrument Performance in Imaging Mass Spectrometry

Spatial resolution is a key parameter in imaging mass spectrometry (IMS). Aside from being a primary determinant in overall image quality, spatial resolution has important consequences on the acquisition time of the IMS experiment and the resulting file size. Hardware and software modifications during instrumentation development can dramatically affect the spatial resolution achievable using a given imaging mass spectrometer. As such, an accurate and objective method to determine the working spatial resolution is needed to guide instrument development and ensure quality IMS results. We have used lithographic and self-assembly techniques to fabricate a pattern of crystal violet as a standard reticle slide for assessing spatial resolution in matrix-assisted laser desorption/ionization (MALDI) IMS experiments. The reticle is used to evaluate spatial resolution under user-defined instrumental conditions. Edgespread analysis measures the beam diameter for a Gaussian profile and line scans measure an “effective” spatial resolution that is a convolution of beam optics and sampling frequency. The patterned crystal violet reticle was also used to diagnose issues with IMS instrumentation such as intermittent losses of pixel data

Enhanced Ion Transmission Efficiency up to <i>m</i>/<i>z</i> 24 000 for MALDI Protein Imaging Mass Spectrometry

The molecular identification of species of interest is an important part of an imaging mass spectrometry (IMS) experiment. The high resolution accurate mass capabilities of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) have recently been shown to facilitate the identification of proteins in matrix-assisted laser desorption/ionization (MALDI) IMS. However, these experiments are typically limited to proteins giving rise to ions of relatively low <i>m</i>/<i>z</i> due to difficulties transmitting and measuring large molecular weight ions of low charge states. Herein we have modified the source gas manifold of a commercial MALDI FT-ICR MS to regulate the gas flow and pressure to maximize the transmission of large <i>m</i>/<i>z</i> protein ions through the ion funnel region of the instrument. By minimizing the contribution of off-axis gas disruption to ion focusing and maximizing the effective potential wall confining the ions through pressure optimization, the signal-to-noise ratios (S/N) of most protein species were improved by roughly 1 order of magnitude compared to normal source conditions. These modifications enabled the detection of protein standards up to <i>m</i>/<i>z</i> 24 000 and the detection of proteins from tissue up to <i>m</i>/<i>z</i> 22 000 with good S/N, roughly doubling the mass range for which high quality protein ion images from rat brain and kidney tissue could be produced. Due to the long time-domain transients (>4 s) required to isotopically resolve high <i>m</i>/<i>z</i> proteins, we have used these data as part of an FT-ICR IMS-microscopy data-driven image fusion workflow to produce estimated protein images with both high mass and high spatial resolutions

Multiple Time-of-Flight/Time-of-Flight Events in a Single Laser Shot for Improved Matrix-Assisted Laser Desorption/Ionization Tandem Mass Spectrometry Quantification

Quantitative matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) approaches have historically suffered from poor accuracy and precision mainly due to the nonuniform distribution of matrix and analyte across the target surface, matrix interferences, and ionization suppression. Tandem mass spectrometry (MS/MS) can be used to ensure chemical specificity as well as improve signal-to-noise ratios by eliminating interferences from chemical noise, alleviating some concerns about dynamic range. However, conventional MALDI TOF/TOF modalities typically only scan for a single MS/MS event per laser shot, and multiplex assays require sequential analyses. We describe here new methodology that allows for multiple TOF/TOF fragmentation events to be performed in a single laser shot. This technology allows the reference of analyte intensity to that of the internal standard in each laser shot, even when the analyte and internal standard are quite disparate in <i>m</i>/<i>z</i>, thereby improving quantification while maintaining chemical specificity and duty cycle. In the quantitative analysis of the drug enalapril in pooled human plasma with ramipril as an internal standard, a greater than 4-fold improvement in relative standard deviation (<10%) was observed as well as improved coefficients of determination (<i>R</i>²) and accuracy (>85% quality controls). Using this approach we have also performed simultaneous quantitative analysis of three drugs (promethazine, enalapril, and verapamil) using deuterated analogues of these drugs as internal standards