Theses and Dissertations from UMD

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    PRINCIPLES FOR NEW OPTICAL TECHNIQUES IN MEDICAL DIAGNOSTICS FOR mHEALTH APPLICATIONS
    (2014) Balsam, Joshua; Bruck, Hugh A; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Medical diagnostics is a critical element of effective medical treatment. However, many modern and emerging diagnostic technologies are not affordable or compatible with the needs and conditions found in low-income and middle-income countries and regions. Resource-poor areas require low-cost, robust, easy-to-use, and portable diagnostics devices compatible with telemedicine (i.e. mHealth) that can be adapted to meet diverse medical needs. Many suitable devices will need to be based on optical technologies, which are used for many types of biological analyses. This dissertation describes the fabrication and detection principles for several low-cost optical technologies for mHealth applications including: (1) a webcam based multi-wavelength fluorescence plate reader, (2) a lens-free optical detector used for the detection of Botulinum A neurotoxin activity, (3) a low cost micro-array reader that allows the performance of typical fluorescence based assays demonstrated for the detection of the toxin staphylococcal enterotoxin (SEB), and (4) a wide-field flow cytometer for high throughput detection of fluorescently labeled rare cells. This dissertation discusses how these technologies can be harnessed using readily available consumer electronics components such as webcams, cell phones, CCD cameras, LEDs, and laser diodes. There are challenges in developing devices with sufficient sensitivity and specificity, and approaches are presented to overcoming these challenges to create optical detectors that can serve as low cost medical diagnostics in resource-poor settings for mHealth.
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    IN VITRO INDUCTION OF POLYPLOIDY IN CERCIS YUNNANENSIS HU ET CHENG
    (2009) Nadler, Joshua Daniel; Coleman, Gary D; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Methods for in vitro induction of polyploid Cercis yunnanensis Hu et Cheng using oryzalin were developed and evaluated. Methods included treating either shoot or callus tissue for different exposure durations with either an aqueous solution of 150 micromolar oryzalin or the addition of oryzalin directly to solid media. Polyploid nuclei were determined by flow cytometry for all oryzalin treatments. Although the results indicate that most tissues measured were likely chimeras with respect to DNA content. Results indicate that treating shoot tissue with an aqueous solution of oryzalin for 12 to 96 hours produced tetraploid plants irrespective of the type of shoot explant treated. An unstable octaploid was formed from the treatment of a pre-cultured lateral shoot in an aqueous solution of oryzalin for 96 hours. In contrast shoots cultured on the solidified media failed to produce polyploid plants and there were no statistical differences between callus treatments regarding polyploid induction.