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For years crystalline silica has been recognized as an occupational hazard of the dusty trades with exposures resulting in silicosis. As recently as 1997, IARC categorized the respirable portion of crystalline silica as a Grade 1 human carcinogen indicating that silica may be implicated in the development of lung cancer. Evidence in the literature indicates that silica may be not only an occupational hazard, but an environmental hazard as well, with patients with no known exposure showing measurable quantities of silica within cancerous tissue samples. This study aims to establish a methodology using computer-controlled scanning electron microscopy to examine silica content in lung cancer tissue. Furthermore, demonstrating that silica is not evenly distributed within the tissue will establish the need to use automated full scanning techniques, such as CCSEM, in order to guarantee that the analysis is not subject to random sampling error or researcher driven error, which may be rendering the traditional random sampling of zones for analysis under-representative of silica concentration in the tissue.

This work evaluated the robust, lightweight DiSCmini (DM) aerosol monitor for its ability to measure the concentration and mean diameter of submicrometer aerosols. Tests were conducted with monodispersed and polydispersed aerosols composed of two particle types (sodium chloride, NaCl, and spark generated metal particles, which simulate particles found in welding fume) at three different steady-state concentration ranges (Low, <103; Medium, 103-104; and High, >104 particles/cm3). Particle number concentration, lung deposited surface area (LDSA) concentration, and mean size measured with the DM were compared to those measured with reference instruments, a scanning mobility particle sizer (SMPS) and a handheld condensation particle counter (CPC). Particle number concentrations measured with the DM were within 16% of those measured by the CPC for polydispersed aerosols. Poorer agreement was observed for monodispersed aerosols (±35% for most tests and +101% for 300-nm NaCl). LDSA concentrations measured by the DM were 96% to 155% of those estimated with the SMPS. The geometric mean diameters measured with the DM were within 30% of those measured with the SMPS for monodispersed aerosols and within 25% for polydispersed aerosols (except for the case when the aerosol contained a substantial number of particles larger than 300 nm). The accuracy of the DM is reasonable for particles smaller than 300 nm but caution should be exercised when particles larger than 300 nm are present.

This work strived to increase knowledge of assessing airborne nanoparticles in the workplace by characterizing nanoparticle concentrations in a workplace using direct-reading instruments, evaluating a DC2000CE diffusion charger, and the creation of a personal diffusion battery (pDB). Direct-reading instruments were used with aerosol mapping and task monitoring to evaluate airborne nanoparticle concentrations in an apparel company that produces waterproof jackets composed of polytetrafluoroethylene membrane laminated fabric. Jacket production required that sewn seams be sealed with waterproof tape applied with hot air (600°C). Particle number concentrations were greater in the sewing and sealing areas than the office area while respirable mass was negligible throughout the facility. The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p<0.0001). The effectiveness of the canopy hoods used to ventilate sealing operations was poor. These measurements support the idea that work places were hot processes are conducted may have substantially greater concentrations of airborne nanoparticles than background measurements even with control measures in place. Laboratory tests were conducted to evaluate a commercially available diffusion charger, the DC2000CE, that measures nanoparticle surface area concentration. The surface area concentrations of unimodal and multimodal polydispersed aerosols measured by the DC2000CE were less than the surface area concentrations measured by the reference instruments. The differences in results were attributed to a difference of measuring active versus geometric surface area concentration and the design of the DC2000CE. The maximum measurable active surface area concentration (2,500 mm2 m-3) was found to be greater than the manufacturer stated maximum (1000 mm2 m-3). Moving or vibrating a DC2000CE while taking measurements can cause the appearance of increased surface area concentration results. The DC2000CE has limitations that must be acknowledged when using the DC2000CE to measure airborne nanoparticle surface area concentrations in a workplace. A four stage pDB (3.2 kg) composed of a screen-type diffusion battery, solenoid valve system, and an electronic controller was developed. The pDB was combined with a CPC and a data inversion was created that could be used to solve for the number median diameter, geometric standard deviation, and particle number concentration of a unimodal distribution. The pDB+CPC with inversion was evaluated using unimodal propylene torch exhaust and incense exhaust. For particle number concentration of particles with diameters less than 100 nm, the pDB+CPC with inversion results were between 86% to 109% of reference instrument results when the inversion did not solve to an inversion constraint and between 6% to 198% for results that solved to an inversion constraint. When coupled with a direct-reading instrument, the pDB with an inversion was able to measure the size distribution of particles with a NMD smaller than 290 nm.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1974. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Laboratory safety has recently become more of an imperative in research laboratories than it has ever been in the past. Recent accidents at several universities have escalated the awareness of safety concerns in laboratory workspaces among the general public and created a greater need for a stronger culture of safety in chemistry research overall. Historically, results and publications have been the top priority of most researchers, not laboratory safety. This thesis discusses a number of laboratory accidents. The first happened in December of 2008 at the University of California, Los Angeles (UCLA) and resulted in the death of a graduate student researcher. Many safety concerns and violations contributed to the fatality. The second accident happened in June of 2014 at the University of Minnesota (UMN). This incident involved an explosion in a fume hood that caused injuries to the researcher as well as a great deal of damage to the hood and experimental setup. Various minor incidents at the University of Vermont (UVM) are also discussed with regards to the effects on laboratory safety at the university. Universities around the country have been able to learn from these accidents in order to prevent similar occurrences in the future. These accidents and their safety ramifications at UCLA, UMN, and UVM are the focus of this thesis. The safety programs at each of these universities are examined and compared with respect to how the incidents have facilitated necessary changes. Finally, future goals and opportunities for the safety program at UVM are suggested.

Limited information is available describing ergonomics issues and physical risk factors for work-related musculoskeletal pain in the eye care clinical environment. The purpose of this thesis was to estimate the distribution of exposure to forceful muscular exertion of neck and shoulder muscles, and to estimate the relative contribution of important components of exposure variance to overall exposure variance. Surface electromyography (EMG) was used to continuously collect muscle activity measurements of the right and left upper trapezius muscles as well as the right and left anterior deltoid muscles throughout two full working days in clinical ophthalmology. The study observed between-exam-within-day-within-subject to be the variance component with the greatest contribution to total exposure variance in most EMG summary measures. For example, 52.1% of the exposure variability could be attributed to the exam and only 18.7% attributable to the day for the mean RMS value of the right upper trapezius. Similar results were found in the left anterior deltoid muscle with 52.7% exposure variability attributable to the exam and 15.7% attributable to the day. For futures investigations, the large between-exam variance implies the need for longer measurement durations in order to obtain more exams and to explore deeper into the physical risk factors the exams.

Thesis (Ph.D.)--RAND Graduate School, 2008. / Includes bibliographical references.

Thesis (doctoral)--Lund University, 1996. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1996. / Added t.p. with thesis statement inserted.