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.

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Published Article / Direct control by government over abattoirs shifted in the late 1980s through privatisation. The legislated food safety system, namely the Hygiene Management System (HMS), coupled with the Hygiene Assessment System (HAS) attempted to address problems of control. The responsibility to implement and maintain these systems is now the responsibility of abattoir operators who must ensure that meat is processed within the risk-based HMS. However requirements for the HMS are scattered throughout legislation, government policies and guideline documents. The research aim was to suggest themes toward the development of an implementation guideline document for HMS implementation by conducting gap assessment audits at abattoirs using the Hygiene Assessment System (HAS).

Thesis (M.Tech.:Chiropractic)-Dept. of Chiropractic, Durban Institute of Technology, 2005 126 leaves, Annexures A-N / Emergency medical personnel have a number of occupational risk factors that are listed in the reviewed literature (Davis and Heaney 2000, Volinn 1997 and Andersson 1999) as risk factors for low back pain. Physical lifting and carrying of patients and equipment increases stress on the lower back, while occupational stress and a high level of patient responsibility are mental risk factors (Davis and Heaney, 2000). Emergency medical personnel that spend long hours in response vehicles, ambulances or helicopters are exposed to vibrational stressors and may therefore have an increased risk of low back pain due to this whole body vibration (Palmer et al, 2000). In addition it has been noted that the number of motor vehicle accidents will also increase the risk of low back pain due to mechanical injury (Cassidy et al, 2003). Low back pain could therefore interfere with their ability to carry out their duties, affect their attitude towards patients and colleagues, impact on the level of patient care required of them, and result in increased absenteeism. Persistence of chronic low back with the inability to perform their duties may result in the need to find alternative employment or result in premature dismissal. The objectives of this study were: to determine if emergency medical personnel have a higher risk factor for the development of low back pain due to their occupation than the general population; as well as determine if an increase in the number of years working in the field (i.e. years of exposure) leads to an increased incidence and / or prevalence of low back pain.

The objective of this study was to compare the effects on eating behavior, lipids, lipoproteins, lipid peroxidation, and glycemic control in women with type 2 diabetes of a high-monounsaturated fat diet (HM) compared to a high-carbohydrate diet (HC). In an outpatient feeding study, ten hypertriglyceridemic postmenopausal type 2 diabetic women alternately for six weeks consumed the HM and HC diets. On the HM diet, 45% of total calories were consumed as carbohydrate and 40% as fat (27% monounsaturated) compared to 55% carbohydrate and 30% fat (10% monounsaturated) in the HC diet. At the beginning and end of each diet phase, total lipids, lipoproteins, lipid peroxidation, and glycemic variables were measured. For 8 days in each diet phase eating pattern frequency, palatability of foods, hunger and fullness were assessed. At the end of each diet phase, taste testing to determine preference for fat was conducted. Total cholesterol was significantly decreased on the HC diet. Serum triglyceride, very low density lipoprotein (VLDL) triglyceride and cholesterol, and apolipoproteins A-1 and B were not significantly different on the two diets. When comparing initial to final values, both diets lowered LDL-C; however, the change was greater on the HM diet. Lipid peroxidation variables improved when the HM diet was consumed. Glycemic variables improved on both diets. No significant differences between total number of eating episodes on the HM and HC diet phases were found. Both diets were rated as highly palatable. Hunger and fullness ratings varied within and between subjects. However, fullness was more commonly experienced than hunger on both HM and the HC diet. Preference for fat was not found at the end ofHM or HC diets. However, subjects differed significantly in ratings for liking of foods that were salty, sour, and bitter when compared to nondiabetic women. Consumption of the HM and HC diets did not result in deterioration of lipid status. The HM diet by virtue of less oxidation of the LDL particle and improvement of glycemic control provides an important advantage over the HC diet. A description of eating behavior of women with type 2 diabetes emerged. / Graduation date: 2000

The ultra-processing of food has become a much more important aspect of dietary patterns and dietary quality in terms of its impact on body weight, diet related diseases, health, and well-being in the past decades. NOVA is a set of guidelines developed that classifies diet quality by degree of food processing. The NOVA guidelines distinguish four categories: unprocessed /minimally processed foods; culinary ingredients; processed foods; and ultra-processed foods. Numerous studies have found an association of ultra-processed foods and health conditions such as obesity and metabolic syndrome. This study analyzed the associations between maternal diet quality as measured by NOVA and maternal anthropometric and neonatal body composition outcomes. The optimal method of nutrition intervention and education for this special population remains unknown; using NOVA may provide researchers with a different lens to assess diet quality and health care professionals with additional vocabulary to convey more tailored messages regarding optimal nutrition strategies for mother and offspring. Using data collected from a large randomized controlled intervention trial at pre and post intervention, this study aimed to compare the NOVA guidelines assessment of maternal diet quality to the parent study assessment of diet quality, the Healthy Eating Index (HEI), using statistical correlations. Secondly, this study aimed to look at the relationship of ultra-processed food intake to the maternal gestational weight gain experience using a logistic regression. Thirdly, this dissertation aimed to explore the relationship between maternal ultra-processed food intake and neonatal lean mass as measured by quantitative magnetic resonance (QMR) and fat free mass as measured by air displacement plethysmography (ADP: PEAPOD). In terms of maternal outcomes, the study found that NOVA and HEI were significantly correlated at pre intervention but not at post intervention. The odds of gaining excessive gestational weight decreased as maternal ultra-processed food intake increased - which was not in the hypothesized direction - when using study participant data. However, the odds of gaining excessive gestational weight increased as maternal ultra-processed food intake increased - which was in the hypothesized direction - when using the Institute of Medicine weight gain recommendations. Also, while obesity did not predict excessive gestational weight gain, those with obesity ultra-processed food intake did predict gestational weight gain. These various inconsistencies are likely due to the instability of the dietary intake data because only one 24 -hour dietary recall was obtained from mother. In addition, the mothers’ diets were very healthy to begin with, where ultra-processed food intake formed about 45% of calories both pre and post intervention, when the national average is 57%. Race was also significant predictors of gestational weight gain for the mothers. Being non-white significantly increased the odds of gaining excessively as did the interaction of having obesity and eating more ultra-processed foods. In terms of neonatal outcomes, findings from this study suggest that length and fat mass are significant predictors of lean mass in neonates. In terms of the impact of maternal ultra-processed food intake, the higher the consumption of ultra-processed food, the greater the neonatal lean mass, which this was not in the hypothesized direction. However, the association was minimal with very small beta weights and regression line, when plotted was quite flat, so that the finding is not clinically meaningful. It remains important to know whether maternal ultra-processed food intake influences gestational weight gain and the body composition of the neonate. Thus, future research should include using similar data analyses on a population with a more nationally representative diet, a larger sample size, and a more robust measure of dietary intake such as three 24-hour recalls. Given that a similar recent study found ultra-processed food to be highly predictive of maternal and neonatal outcomes, and many other studies have demonstrated that ultra-processed food is related to several health conditions in many countries that this study did not measure, it seems prudent for healthcare providers to take advantage of prenatal visits as a window of opportunity to encourage the consumption of unprocessed and minimally foods and help women make informed decisions regarding ultra-processed foods.

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.

published_or_final_version / Community Medicine / Master / Master of Public Health

published_or_final_version / Community Medicine / Master / Master of Public Health