Publications by authors named "Austin D"

A linear wire ion trap (LWIT) with both electron ionization (EI) and single photon ionization (SPI) sources was built. The SPI was provided by a vacuum ultraviolet (VUV) lamp with the ability to softly ionize organic compounds. The VUV lamp was driven by a pulse amplifier, which was controlled by a pulse generator, to avoid the detection of photons during ion detection.

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The interaction of intense laser pulses with nanoscale particles leads to the production of high-energy electrons, ions, neutral atoms, neutrons and photons. Up to now, investigations have focused on near-infrared to X-ray laser pulses consisting of many optical cycles. Here we study strong-field ionization of rare-gas clusters (10 to 10 atoms) using two-cycle 1.

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A systematic study of few-cycle pulse laser induced damage threshold (LIDT) determination was performed for commercially-available ultra-broadband optics, (i.e. chirped mirrors, silver mirrors, beamsplitters, etc.

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Military Service Members are often exposed to high levels of occupational noise, solvents, and other exposures that can be damaging to the auditory system. Little is known about hearing loss and how it progresses in Veterans following military service. This epidemiology study is designed to evaluate and monitor a cohort of Veterans for 20 years or more to determine how hearing loss changes over time and how those changes are related to noise exposure and other ototoxic exposures encountered during military service.

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The recent development of non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS) has allowed the non-invasive assessment of cerebellar function in humans. Early studies showed that cerebellar activity, as reflected in the excitability of the dentate-thalamo-cortical pathway, can be assessed with paired stimulation of the cerebellum and the primary motor cortex (M1) (cerebellar inhibition of motor cortex, CBI). Following this, many attempts have been made, using techniques such as repetitive TMS and transcranial electrical stimulation (TES), to modulate the activity of the cerebellum and the dentate-thalamo-cortical output, and measure their impact on M1 activity.

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We present a variant of spatially encoded spectral shearing interferometry for measuring two-dimensional spatio-temporal slices of few-cycle pulses centered around 2 μm. We demonstrate experimentally that the device accurately retrieves the pulse-front tilt caused by angular dispersion of two-cycle pulses. We then use the technique to characterize 500-650 μJ pulses from a hollow fiber pulse compressor, with durations as short as 7.

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We use a high harmonic generated supercontinuum in the soft X-ray region to measure X-ray absorption near edge structure (XANES) spectra in polythiophene (poly(3-hexylthiophene)) films at multiple absorption edges. A few-cycle carrier-envelope phase-stable laser pulse centered at 1800 nm was used to generate a stable soft X-ray supercontinuum, with amplitude gating limiting the generated pulse duration to a single optical half-cycle. We report a quantitative transmission measurement of the sulfur edge over the range 160-200 eV and the carbon edge from 280 to 330 eV.

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Aims: To demonstrate that analysis of urinary C-peptide across multiple study sites in the context of an intervention trial (DEFEND-2) is a viable alternative to mixed meal testing and delivers results that correlate to mixed meal testing estimation of endogenous insulin production.

Methods: Second morning void urine was collected for analysis and was available from 161 subjects at baseline (55 placebo, 106 otelixizumab), and 146 subjects (47 placebo, 99 otelixizumab) at month 12. Urinary C-peptide concentration was corrected for urinary creatinine [urinary C-peptide/creatinine ratio (UCPCR)] and serum C-peptide from the mixed meal tolerance test was calculated using area under the plasma concentration-time curve (AUC) normalized over 120 min.

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Spontaneous coronary artery dissection (SCAD) is an uncommon but important cause of acute coronary syndrome. The diagnosis of SCAD by an angiogram alone can be challenging and the increasing use of intracoronary imaging has proven an invaluable diagnostic adjunct in this regard. The appropriate initial management of SCAD has been a matter of significant debate.

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Article Synopsis
  • The study examines high-harmonic generation in three organic solvents—toluene, ortho-xylene, and fluorobenzene—using a 1.8 μm ultrashort pulse.
  • Chemical substitutions in these compounds significantly affect the amplitude and phase of emissions from the highest occupied molecular orbital, despite minimal changes to the orbital itself.
  • The research attributes these effects to the tunnel ionization step, highlighting its dependence on the wave function's characteristics, with implications for phase-sensitive high-harmonic generation spectroscopy experiments.
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The public health implications of growing numbers of older adults at risk for dementia places pressure on identifying dementia at its earliest stages so as to develop proactive management plans. The prodromal dementia phase commonly identified as mild cognitive impairment is an important target for this early detection of impending dementia amenable to treatment. In this paper, we propose a method for home-based automatic detection of mild cognitive impairment in older adults through continuous monitoring via unobtrusive sensing technologies.

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Estimation of the biological profile of unidentified human remains is a critical component of an anthropologic evaluation of unidentified human remains. The profile is used to search for missing persons that may match the decedent. The individual components of sex, ancestry, stature, and age at death require reliable methods to ensure accurate recording of these biological markers.

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Over the past few decades, the field of forensic anthropology has seen major advancements and experienced a considerable growth of professionals in medical examiner/coroner offices. Despite this expansion, misconceptions regarding the role and utility of the anthropologist in the medicolegal setting still exist. This article brings together practitioners employed full-time in four medical examiner's offices, with each practitioner providing a unique perspective and emphasis regarding their role as an anthropologist.

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Background: Prostate cancer treatment often results in significant psycho-sexual challenges for men following treatment; however, many men report difficulty in accessing appropriate care.

Methods: A randomized controlled trial was undertaken to assess the efficacy of a 10-week self-guided online psychological intervention called My Road Ahead (MRA) for men with localized prostate cancer in improving sexual satisfaction. Participants were randomized to 1 of 3 conditions MRA alone or MRA plus online forum, or forum access alone.

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We report a linear ion trap (LIT) in which the electric field is formed by fine wires held under tension and accurately positioned using holes drilled in two end plates made of plastic. The coordinates of the hole positions were optimized in simulation. The stability diagram and mass spectra using boundary ejection were compared between simulation and experiment and good agreement was found.

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Background: Android tablet computers can be valuable tools for data collection, but their usability has not been evaluated in community-based participatory research (CBPR).

Objectives: This article examines the usability of a low-cost bilingual touchscreen computerized survey system using Android tablets, piloted with a sample of 201 community residents in Tampa, Florida, from November 2013 to March 2014.

Methods: Needs assessment questions were designed with the droidSURVEY software, and deployed using Android tablet computers.

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Purpose: In the Noise Outcomes in Servicemembers Epidemiology Study, Veterans recently separated from the military undergo comprehensive assessments to initiate long-term monitoring of their auditory function. We developed the Tinnitus Screener, a four-item algorithmic instrument that determines whether tinnitus is present and, if so, whether it is constant or intermittent, or whether only temporary tinnitus has been experienced. Predictive validity data are presented for the first 100 Noise Outcomes in Servicemembers Epidemiology Study participants.

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Background: Benign prostatic hyperplasia (BPH) is treated with 5α-reductase inhibitors (5ARI). These drugs inhibit the conversion of testosterone to dihydrotestosterone resulting in apoptosis and prostate shrinkage. Most patients initially respond to 5ARIs; however, failure is common especially in inflamed prostates, and often results in surgery.

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We report on the characterization of space-time couplings in high-energy sub-2-cycle 770 nm laser pulses using a self-referencing single-frame method. Using spatially encoded arrangement filter-based spectral phase interferometry for direct electric field reconstruction, we characterize few-cycle pulses with a wavefront rotation of 2.8×10  rev/s (1.

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The hyoid bone supports the important functions of swallowing and speech. At birth, the hyoid bone consists of a central body and pairs of right and left lesser and greater cornua. Fusion of the greater cornua with the body normally occurs in adulthood, but may not occur at all in some individuals.

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Irritable Bowel Syndrome (IBS) is a common condition affecting around 10-20% of the population and associated with poorer psychological well-being and quality of life. The aim of the current study was to explore the efficacy of the Common Sense Model (CSM) using Structural Equation Modelling (SEM) in an IBS cohort. One hundred and thirty-one IBS patients (29 males, 102 females, mean age 38 years) participating in the IBSclinic.

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