Thesis (Ph.D.)--Brown University, 2005. / Vita. Thesis advisor: Christine A. Biron. Includes bibliographical references (leaves 32-41, 62-65, 90-93, 118-123, 154-159). Also available online.

Airborne diseases transmitted through tiny respiratory droplets such as the Coronavirus disease can not only rapidly infect others but also worsen the symptoms in already affected individuals. People with COVID-19 are more likely to develop severe acute respiratory syndrome or SARS through aspiration pneumonia, which refers to when some virus-laden droplets are inhaled into the airway and lungs. This project aims to study droplet behavior in the upper airway in order to investigate methods to reduce the risk of infected droplets entering the upper airway in a patient. The project involves the design and development of a cough emulator that can simulate a human cough accurately, build a physical model of the upper airway using a material similar in texture to the human windpipe, and measure and track the generated particles as they transverse through the upper airway and exit the mouth. The criteria needed to be met to design, manufacture, and evaluate a cough emulator reproducing a human-like cough include the volume, pressure, and flow rate of a cough. To evaluate the validity and accuracy of the device, the number, size, and spread of cough droplets are compared to that of a real cough. The upper airway is fabricated using Elastic 50A resin due to its flexible and durable properties, and texture similarity to the tissue of the human trachea. In addition, particles are tracked in the upper airway using a Charged Couple Device (CCD) Camera.

The COVID-19 outbreak highlighted the important role that diagnostic tests play in the healthcare system. To reduce the impact of infectious disease outbreaks, the development of rapid and cost-effective point-of-care-tests (POCTs) is crucial. With the dissemination of the Monkeypox (Mpox) virus, it became a necessity to produce POCTS that are inexpensive and easy to use. This work explored the construction of two colorimetric assays that aim to detect Mpox genetic signatures. One is based on the split-peroxidase-like deoxyribozyme probes (sPDz), while the other utilizes a cascade system of split RNA-cleaving deoxyribozyme (sDz) and peroxidase-like deoxyribozyme (PDz). Both rely on catalytic probes as well as a G-Quadruplex (G4) structure to facilitate the production of a color change in the presence of the genetic signatures of Mpox. The sPDz probes were initially tested with synthetic genomic fragments of Mpox and other Orthopoxviruses for selectivity purposes. The sPDz probes were then further optimized. The optimal sPDz probes and the sDz/PDz cascade system were tested with an amplified genome fragment of Mpox. The genome fragments were generated by using both symmetric and asymmetric polymerase chain reaction (PCR). With further optimization to increase the signal-to-background ratio, these probes may show promise as an assay that may have the potential to be incorporated to develop POCTs.

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published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

published_or_final_version / Zoology / Master / Master of Philosophy