The increasing burden of chronic disease in ageing populations has shifted focus towards illness prevention and the self-management of health. Middle-aged and menopausal women’s transitioning bodies, specifically with respect to weight gain and changes in body fat composition, have received much attention by public health officials during the alleged obesity epidemic. In addition to these transformations, socioeconomic status has been shown to interact with obesity by decreasing the psychosocial health of vulnerable women. Although public health actions have targeted the health practices of clinically obese women throughout the menopausal transition, their effectiveness is limited because of existing socioeconomic inequalities, narrow focus on body weight interventions, and the psychosocial impact of an obesity stigma. Drawing on Bourdieu’s sociocultural theory of practice, and namely his concepts of body habitus and symbolic violence, this study aims: (a) to identify the norms and values of clinically overweight and obese postmenopausal women from contrasting socioeconomic backgrounds with regard to the ways they treat and care for their body, and (b) to outline the socio-cultural processes which incline them (or not) to pursue weight-loss strategies. Forty semi-structured interviews were conducted with clinically overweight and obese postmenopausal women from underprivileged (n=20) and middle class (n=20) milieus in the city of Sherbrooke, Québec. An intersectional (gender, age, socioeconomic status) thematic analysis was employed in order to analyze the data and identify emergent themes within and between both socioeconomic groups. This thesis is composed of two distinct studies. The first identifies the diverse contexts of occurrence of obesity stigma and weight shaming, as well as the contrasting responses between the two socioeconomic groups. Although all participants experienced obesity stigma, participants from lower social positions were more vulnerable to the psychosocial impact of dominant obesity discourses. In contrast, a higher access to social, economic, and educational resources provided middle-class women with more protection from weight shaming and discrimination. In the second article, from a public health perspective, the analysis of hierarchies of priorities, perception of control, as well as barriers and facilitators show that weight management needs to be understood as the outcome of a social process in which living conditions, material and psychosocial, offer a number of conditions of possibilities. Globally speaking, middle-class conditions privileged the adherence to public health recommendations, while socially deprived conditions inclined women to adopt unsustainable and risk-oriented weight-loss practices.

Although reducing eating rate is frequently advocated for control of food intake, empirical evidence is limited and inconsistent. The present study sought to address the methodological concerns inherent in previous studies that could account for these inconsistent results. In addition, it extended the results of a preliminary study coauthored by this writer (Azrin, Kellen, Brooks, Ehle, & Vinas, 2009) by obtaining two measures of satiation; the subjective sensation of satiation and the objective measure of food eaten. In the present study, 14 male participants consumed two meals, one meal at an instructed fast rate and one meal at an instructed slow rate. Slow eating was accompanied by enhancing the conditioned stimuli associated with eating (time spent chewing and savoring of taste). The meals were eaten on two consecutive days at the same time, in a counterbalanced order, in the participant's natural environment, and were characteristic of each participant's reported typical diet. Participants ate until reaching subjective satiation, i.e., the point at which they felt "comfortably full with no desire to continue eating". Consuming food at a slow rate was found to help participants achieve a greater degree of subjective satiation with comparable amounts of food intake. Participants consumed on average 37% more food when eating fast. These results suggest that slow eating enhances subjective satiation and reduces food consumption; and may constitute an effective means of weight management. A theoretical explanation is suggested as to why previous studies examining the effect of eating rate on satiation have produced inconsistent results.

Negative body image and preoccupation with weight are the norm for most women and girls in Western society, despite their potentially harmful consequences for psychological and physical wellness. While we know that many in this population experience negative feelings towards their bodies, we do not know if their beliefs about their body size are accurate and what effect a correct or incorrect assessment of one's body size has in terms of actual behavior. I examine this question among adolescent girls using data from the 2002 Health Behaviors in School-Age Children Survey. With a sample of 2,784 girls between the ages of 11 and 17, I run Poisson regression models to assess the relationship between actual and perceived body size and healthy versus unhealthy weight control behaviors, controlling for a number of indicators known to be associated with weight control, including parent and peer relationships, media exposure, and age of first menstruation. Results indicate that a discrepancy between actual and perceived body size is associated with increases in both positive and negative weight control behaviors, though the association with negative weight control behaviors is much larger. Starting puberty later is associated with a decrease in both types of these behaviors. Difficult family relationships appear to be more strongly associated with negative weight control than positive weight control. Other associations are discussed and suggestions for future research are offered.

Phenylethanolamine N-methyltransferase (Pnmt) is the enzyme in the catecholamine pathway responsible for converting norepinephrine to epinephrine. Pnmt is present in numerous areas; however, the scope of its expression in the mouse brain is not fully understood. A genetic mouse model was generated by the Ebert lab that exhibited the selective destruction of all Pnmt+ cells through the induction of apoptosis by Diphtheria Toxin A. Unexpected phenotypic defects arose that are characterized by metabolic weight deficits and motor ataxia. The distribution of Pnmt+ neurons was examined throughout the hypothalamus and cerebellum to generate an anatomical map of current and historical Pnmt expression using various histochemical methods. Historical Pnmt expression appears more extensive than current expression levels at the adult stage, indicating that certain cells in the mouse brain may have experienced transient Pnmt expression. The presence of Pnmt in these regions suggests that the destruction of these neurons may play a role in the phenotypic defects observed in the ablation mouse model. Gaining a more comprehensive understanding of the potential role of Pnmt in these areas may elucidate new drug targets or novel methods to treat obesity and motor control disorders such as ataxia.

This study investigated the connection between Body Dissatisfaction and Drive for Thinness to several psychological correlates: Ineffectiveness, Interpersonal Distrust, Perfectionism, Interoceptive Awareness, and Maturity Fears. Regression analyses indicated that these five correlates together accounted for 23% of the variance in a measure of Body Dissatisfaction. Body Dissatisfaction and the five correlates together accounted for 52% of the variance in a measure of Drive for Thinness. Results of the path analysis confirmed that Ineffectiveness, Interoceptive Awareness and Maturity Fears were the strongest predictors of Body Dissatisfaction. In turn, Body Dissatisfaction, Ineffectiveness and Interoceptive Awareness were the strongest predictors of Drive for Thinness. Gender differences and prevalence rates of eating disordered behavior were reviewed. Consistent with other research, this study confirmed high levels of bingeing and purging behavior (44%) among college men and women. / Ph. D.

The purpose of this study was to explore student athletes' weight-control behaviors. Data consisted of student athletes' responses to a modified version of the Michigan State Weight-Control Survey (Dummer, Rosen, Heusner, Roberts, & Counsilman, 1987). Specifically, the study was designed to explore the following research hypotheses: 1. There is no significant relationship between the weight-control behaviors of athletes competing in sports with weight restrictions (e.g., wrestling) and sports without weight restrictions (e.g., tennis). 2. There is no significant relationship between the weight-control behaviors of athletes competing in sports with subjective judging (e.g., diving) and sports with objective scoring (e.g., swimming). 3. There is no significant relationship between the weight-control behaviors of male athletes and female athletes. The sample was drawn from intact athletic teams at the university under study. All members of the selected teams were invited to participate. The results of this research contributed to both practice and research. Athletic department staff and coaches, student affairs practitioners, and health care practitioners were made more aware of weight-control issues for athletes and might design programs and services to address the issue. The study also lays the groundwork for future research. Scholars may wish to examine other elements of sport (e.g., level of competition, seasonal demands) and their effects on the weight-control behaviors of athletes. The results revealed that there is a significant relationship between weight-control behaviors and the type of weight restrictions (weight restricted versus non-weight restricted) a sport places on athletes (p < .05). There is also a significant relationship between the sex of athletes and the weight-control behavior that they engage in (P < .05). The relationship between the weight-control behaviors and the type of judging (subjective versus objective scoring) involved in the sport was also examined. Though the relationship was not significant at the p = .05 level, it was significant at the p = .1 level. The results of this research addressed an existing gap in the current body of knowledge. There is very little research about weight-control behaviors of athletes in specific groups of sports. Better understanding the demands that different types of sports place on athletes may enable future scholars and practitioners to better serve the population. / Master of Arts

Soluble, thermally stable phosphorus containing polyimides have been synthesized to controlled molecular weights and well-defined phthalimide endgroups via solution imidization. They were characterized by intrinsic viscosity, DSC, TGA, and thermomechanical measurements. Molecular weight control was successful and these polyimides were thermally stable via dynamic TGA up to 500°C. Flame resistance was suggested by the 10-20 % of char yield observed in air at 750°C. Good tensile modulus (500-550 ksi) via stress-strain measurements and excellent adhesion to Ti-6AI-4V substrates through single lap shear tests was demonstrated. Investigations of the effects of molecular weight and end group on thermal and mechanical properties of reactive amine terminated and non-reactive phthalic anhydride terminated PMDA-mBAPPO polyimides were pursued. Polyimides with non-reactive end groups do not crosslink and, hence, were essential for controlled processability. Rheological behavior was investigated with a parallel plate type viscometer and the results confirmed the thermoplastic nature of these systems. Phenyl ethynyl endcapped polyimides were synthesized for a broad based investigation of their processibility and mechanical properties. Thermally stable soluble polyimide oligomers were synthesized via the poly(amic acid) precursor route followed by subsequent solution imidization. These polyimides were successfully crosslinked upon heating, without the evolution of volatile products. The phenyl ethynyl endcapped polymers (T_cure ~ 350-400°C) exhibited a wider processing window above Tg, relative to the unsubstituted acetylene endcapped polymers (T_cure ~ 200°C). Studies of the chemorheological behavior of these polyimides as a function of varying temperatures and times were conducted. This research allows the conclusion that high Tg, thermostable, and solvent resistant new networks suitable for structural adhesives and matrix resins have been identified. This was proven by characterization of these novel networks. Ninety-nine percent gel fraction networks were observed after cure at 380°C for 60 minutes. Thermomechanical properties such as tensile properties, adhesion properties, creep behavior, and heat distortion temperatures have been generated which illustrate the excellent dimensional stability and mechanical properties achievable at optimum crosslink density. Polyarylene ether sulfones were also studied which demonstrated the desirable combination of excellent thermal stability and good mechanical properties. Biphenyl-based polysulfones were synthesized and endcapped with 3-phenyl ethyny] functional groups. High Tg, thermostable, ductile and solvent resistant networks were prepared after curing at 380°C. Thermo-mechanical behavior, including tensile properties and dynamic mechanical analyses have been determined and are reported in this thesis. / Ph. D.

Master of Science / Department of Human Nutrition / Weiqun Wang / Weight control through either dietary calorie restriction (DCR) or exercise is associated with cancer prevention in animal models. However, the underlying mechanisms are not fully defined. Bioinformatics approaches using genomics, proteomics, and lipidomics were employed to elucidate the profiling changes of genes, proteins, and phospholipids in response to weight loss by DCR or exercise in a mouse skin cancer model. SENCAR mice were randomly assigned into 4 groups for 10 weeks: ad lib-fed sedentary control, ad lib-fed exercise (AE), exercise but pair-fed isocaloric amount of control (PE), and 20% DCR. Two hours after topical TPA treatment, skin epidermis was analyzed by Affymetrix for gene expression, DIGE for proteomics, and lipidomics for phospholipids. Body weights were significantly reduced in both DCR and PE but not AE mice versus the control. Among 39,000 transcripts, 411, 67, and 110 genes were significantly changed in DCR, PE, and AE, respectively. The expression of genes relevant to PI3K-Akt and Ras-MAPK signaling was effectively reduced by DCR and PE as measured through GenMAPP software. Proteomics analysis identified ~120 proteins, with 22 proteins significantly changed by DCR, including upregulated apolipoprotein A-1, a key antioxidant protein that decreases Ras-MAPK activity. Of the total 338 phospholipids analyzed by lipidomics, 57 decreased by PE including 5 phophatidylinositol species that serve as PI3K substrates. Although there were many impacts that we still need to characterize, it appears that both Ras-MAPK and PI3K-Akt signaling pathways are the key cancer preventive targets that have been consistently demonstrated by three bioinformatics approaches.

Doctor of Philosophy / Department of Human Nutrition / Weiqun Wang / Weight control via dietary caloric restriction and/or exercise has been demonstrated for cancer prevention. However, the underlying mechanisms are not clear. Previous studies in our lab showed that IGF-1 and IGF-1-dependent signaling were reduced by weight control. To confirm the requirement of IGF-1 reduction for cancer prevention, we restored IGF-1 in the exercised mice, which partially reversed the reduction of TPA-induced PI3K expression and PI3K-related 38:4 PI substrate. To explore the overall mechanistic impact, we further studied the effect of weight control on the profiles of lipid, gene and protein expression in TPA treated skin tissues. The mice were randomly assigned into 4 groups: ad libitum-fed sedentary control (control), ad libitum-fed exercise (AL+Exe), exercise but pair-fed at the amount of control (PF+Exe), and 20% of dietary calorie restriction (DCR). At the end of 10 weeks, the mice were treated with TPA topically for two hours. The body weights were significantly reduced in DCR and PF+Exe but not AL+Exe mice when compared with the control. Plasma and skin tissue triacylglycerides were significantly decreased in PF+Exe and DCR groups but not AL+Exe. Similar impact was found for the diacylglyceride profile in both plasma and skin tissue accordingly. Using Affymetrix microarray, 784, 223, and 152 probe sets were respectively found significantly changed by DCR, PF+Exe, and AL+Exe. PF+Exe and DCR showed similar impact on signaling pathways-related gene expression as analyzed by GenMAPP. Of the total 86 proteins identified by 2D-DIGE proteomics, 20 proteins were significantly changed by DCR. Overall, our results showed weight control via DCR or pair-fed exercise rather than exercise with ad libitum feeding significantly reduced body weight and body fat, resulting in reduction of IGF-1 and IGF-1-induced signaling such as PI3K and PI-related pathway. The overall impact upon lipid profiling and gene and protein expression by weight loss suggests many other mechanistic targets. Although we could not ambitiously clarify all the changes were related to anticancer mechanisms in the scope of this study, understanding of the relationship between weight control and TPA-induced skin cancer risk as well as IGF-1-dependent signaling pathways may reveal intrinsic mechanisms and provide novel approaches to prevent cancer in the future studies.

published_or_final_version / Community Medicine / Master / Master of Public Health