Development and Characterization of Plasma-based Sources for Ambient Desorption/Ionization Mass Spectrometry

Thesis (Ph.D.) - Indiana University, Chemistry, 2011A number of atmospheric-pressure ionization sources for mass spectrometry has recently appeared in the literature to yield a field that is collectively referred to as Ambient Desorption/Ionization-Mass Spectrometry (ADI-MS). These sources include, among others, Desorption ElectroSpray Ionization (DESI), Direct Analysis in Real Time (DART), the Flowing Atmospheric-Pressure Afterglow (FAPA), and the Low-Temperature Plasma (LTP) probe. Collectively, these ADI-MS sources offer numerous advantages over conventional ionization sources, including direct analysis of solid, liquid, and gaseous samples, high ionization efficiency, and soft ionization. Additionally, their ability to analyze samples directly with no pretreatment dramatically reduces analysis times. The ultimate ambient ionization source would be one that is capable of desorbing and ionizing a broad range of analytes (polar, non-polar, small molecules, biopolymers, etc.) while being minimally influenced by matrix effects. While the plasma-based ADI-MS sources, such as FAPA, DART, and LTP, have been shown to be capable of efficiently ionizing a range of small molecules, few investigations have been aimed at understanding desorption and ionization processes or matrix effects that occur with them. At present, the performance and fundamental characteristics of the FAPA source, developed in our research group, and the LTP probe, developed at Purdue University, are being evaluated through optical and mass-spectrometric methods. The FAPA source consists of a direct-current, atmospheric-pressure glow discharge in a pin-to-plate configuration. A hole in the plate allows ionized and excited plasma species to interact directly with a sample, while physically and electrically isolating the discharge from the sample-introduction region. Conversely, the LTP probe is a high-voltage, alternating-current, dielectric-barrier discharge that interacts directly with a sample. While the fundamental processes governing these discharges are quite different, mass spectra produced with both sources are very similar. The major differences are in achievable detection limits and susceptibility to matrix effects, with the FAPA sources routinely performing better. Direct, fundamental comparisons among the FAPA source, the LTP probe, and DART are made

Performance Pressure and Resource Allocation in Washington

Based on interviews with state, district, and school officials, explores how performance pressures have changed resource allocation decisions. Examines reform goals and how Washington's finance system impedes efforts to link resources to student learning

Case 12 : Policy Meets Practice – People Who Inject Drugs (PWID)

Dr. Silverman is the Chief of Infectious Diseases at London Health Sciences Centre (LHSC) and St. Joseph’s Health Care in London, Ontario. He is concerned about the increasing prevalence of people who inject drugs (PWID) in London, and the risk to PWID of bacterial infections due to contamination (e.g., improperly or unsterilized injection equipment, skin not being sterilized before injection). Of primary concern is the risk of infective endocarditis (IE), an infection in a patient’s heart. Treatment for IE entails antibiotics administered through the intravenous (IV) route. IE is generally treated through home care; in London, the South West Community Care Access Centre (CCAC) is responsible for delivering home care. To treat IE at home, a patient would need a peripherally inserted central catheter (a PICC-line) and assistance from a CCAC nurse to administer the antibiotics. This option, however, is not viable for some patients, including those who fall under the category of PWID or who may not have a fixed address. In the case of PWID, the PICC-line, in effect, becomes a “highway” for injecting other drugs; in instances where a patient may not have secure housing or be homeless, the CCAC nurse may not be able to track down the individual. When a patient in one of these situations is being treated for IE, it puts the care team in a difficult position. The alternatives to home care are hospital admittance or no treatment at all, neither of which are ideal solutions. Dr. Silverman is currently in this position, as he must decide on a treatment plan for Mr. W., a patient who has IE, has struggled with drug addiction (the likely cause of his IE), and who does not have stable housing. In making his decision, Dr. Silverman has included on Mr. W.’s care team two other physicians from LHSC, a representative from the CCAC, and the managing director of London CAReS, a community-based housing-first organization. The care team must determine the best treatment plan for Mr. W

The InfraRed Imaging Spectrograph (IRIS) for TMT: Reflective ruled diffraction grating performance testing and discussion

We present the efficiency of near-infrared reflective ruled diffraction gratings designed for the InfraRed Imaging Spectrograph (IRIS). IRIS is a first light, integral field spectrograph and imager for the Thirty Meter Telescope (TMT) and narrow field infrared adaptive optics system (NFIRAOS). We present our experimental setup and analysis of the efficiency of selected reflective diffraction gratings. These measurements are used as a comparison sample against selected candidate Volume Phase Holographic (VPH) gratings (see Chen et al., this conference). We investigate the efficiencies of five ruled gratings designed for IRIS from two separate vendors. Three of the gratings accept a bandpass of 1.19-1.37 {\mu}m (J band) with ideal spectral resolutions of R=4000 and R=8000, groove densities of 249 and 516 lines/mm, and blaze angles of 9.86 and 20.54 degrees, respectively. The other two gratings accept a bandpass of 1.51-1.82 {\mu}m (H Band) with an ideal spectral resolution of R=4000, groove density of 141 lines/mm, and blaze angle of 9.86{\deg}. We measure the efficiencies off blaze angle for all gratings and the efficiencies between the polarization transverse magnetic (TM) and transverse electric (TE) states. The peak reflective efficiencies are 98.90 +/- 3.36% (TM) and 84.99 +/- 2.74% (TM) for the H-band R=4000 and J-band R=4000 respectively. The peak reflective efficiency for the J-band R=8000 grating is 78.78 +/- 2.54% (TE). We find that these ruled gratings do not exhibit a wide dependency on incident angle within +/-3{\deg}. Our best-manufactured gratings were found to exhibit a dependency on the polarization state of the incident beam with a ~10-20% deviation, consistent with the theoretical efficiency predictions.Comment: Proceedings of the SPIE, 9147-34

A Systematic Review of Genetic Testing and Lifestyle Behaviour Change: Are We Using High-Quality Genetic Interventions and Considering Behaviour Change Theory?

Background: Studying the impact of genetic testing interventions on lifestyle behaviour change has been a priority area of research in recent years. Substantial heterogeneity exists in the results and conclusions of this literature, which has yet to be explained using validated behaviour change theory and an assessment of the quality of genetic interventions. The theory of planned behaviour (TPB) helps to explain key contributors to behaviour change. It has been hypothesized that personalization could be added to this theory to help predict changes in health behaviours. Purpose: This systematic review provides a detailed, comprehensive identification, assessment, and summary of primary research articles pertaining to lifestyle behaviour change (nutrition, physical activity, sleep, and smoking) resulting from genetic testing interventions. The present review further aims to provide in-depth analyses of studies conducted to date within the context of the TPB and the quality of genetic interventions provided to participants while aiming to determine whether or not genetic testing facilitates changes in lifestyle habits. This review is timely in light of a recently published “call-to-action” paper, highlighting the need to incorporate the TPB into personalized healthcare behaviour change research. Methods: Three bibliographic databases, one key website, and article reference lists were searched for relevant primary research articles. The PRISMA Flow Diagram and PRISMA Checklist were used to guide the search strategy and manuscript preparation. Out of 32,783 titles retrieved, 26 studies met the inclusion criteria. Three quality assessments were conducted and included: (1) risk of bias, (2) quality of genetic interventions, and (3) consideration of theoretical underpinnings – primarily the TPB. Results: Risk of bias in studies was overall rated to be “fair.” Consideration of the TPB was “poor,” with no study making reference to this validated theory. While some studies (n = 11; 42%) made reference to other behaviour change theories, these theories were generally mentioned briefly, and were not thoroughly incorporated into the study design or analyses. The genetic interventions provided to participants were overall of “poor” quality. However, a separate analysis of studies using controlled intervention research methods demonstrated the use of higher-quality genetic interventions (overall rated to be “fair”). The provision of actionable recommendations informed by genetic testing was more likely to facilitate behaviour change than the provision of genetic information without actionable lifestyle recommendations. Several studies of good quality demonstrated changes in lifestyle habits arising from the provision of genetic interventions. The most promising lifestyle changes were changes in nutrition. Conclusions: It is possible to facilitate behaviour change using genetic testing as the catalyst. Future research should ensure that high-quality genetic interventions are provided to participants, and should consider validated theories such as the TPB in their study design and analyses. Further recommendations for future research are provided