Early impact of a new food store intervention on health-related outcomes

Neighbourhood food environments influence what people choose to eat and consequently affect their health. Literature suggests that having supermarkets/grocery stores with healthier food options in a neighbourhood supports intake of healthy food as opposed to having abundance of fast food and convenience stores. This thesis systematically reviewed published literature on new food store interventions on health-related outcomes (manuscript 1), and examined early health-related impact of a community-based food intervention in Saskatoon (manuscript 2). The systematic review addressed the question ‘How do new food store (supermarket/grocery store) interventions influence health-related outcomes in adults?’ The review followed the guidelines recommended by the Effective Public Health Practice Project (EPHPP) and identified 11 records representing 7 interventions. The methodological quality rating found that 6 studies were of ‘weak’ methodological quality, one was of ‘moderate’ and two studies had ‘strong’ methodological quality. Relevant outcomes reported by these studies were fruit and vegetable consumption, self-rated health, psychological health, BMI, perceptions of food access, and household food availability. Of these outcomes, perceptions of food access and psychological health showed significant improvement; however, other outcomes showed mixed results. A prospective longitudinal study was conducted to investigate the health-related impact of a new food store in a former food desert in Saskatoon. One hundred and fifty-six shoppers of the new food store were followed-up repeatedly and their health-related outcomes were assessed using a questionnaire. A generalized estimating equations approach was used for data analysis. Study participants were mainly female, Aboriginal, of low income, and had high school and some post-secondary education. They showed dose-response associations between the frequency of use of the new grocery store and the odds of reporting household food security, mental health, and BMI over time, and these associations were significantly modified by participants’ level of education, household income, and pre-existing chronic conditions, respectively. Further, having multiple disadvantaged conditions (Aboriginal ethnicity, seniors, low-income and low-education) significantly modified the effect of the new grocery store use on participants’ mental health. Although the systematic review suggested that previous studies yielded conflicting findings, this thesis research revealed convincing results. In contrast to the limited body of literature, this study found that when the shopping frequency is taken into account, the new grocery store did have a positive effect on mitigating household food security, mental health, and BMI. Further, socioeconomic status, multiple disadvantage, and previous chronic diseases moderate these effects. The results are valuable to advance the knowledge in food environment interventions research

Enhanced Thermoelectric Power and Electronic Correlations in RuSe2_2

We report the electronic structure, electric and thermal transport properties of Ru$_{1-x}$Ir$_{x}$Se$_2$ ($x \leq 0.2$). RuSe$_2$ is a semiconductor that crystallizes in a cubic pyrite unit cell. The Seebeck coefficient of RuSe$_2$ exceeds -200 $\mu$V/K around 730 K. Ir substitution results in the suppression of the resistivity and the Seebeck coefficient, suggesting the removal of the peaks in density of states near the Fermi level. Ru$_{0.8}$Ir$_{0.2}$Se$_{2}$ shows a semiconductor-metal crossover at about 30 K. The magnetic field restores the semiconducting behavior. Our results indicate the importance of the electronic correlations in enhanced thermoelectricity of RuSb$_{2}$.Comment: 6 pages, 4 figure

Vacancy-Driven Noncubic Local Structure and Magnetic Anisotropy Tailoring in FeₓO-Fe₃-{δ}_O₄ Nanocrystals

In contrast to bulk materials, nanoscale crystal growth is critically influenced by size- and shape-dependent properties. However, it is challenging to decipher how stoichiometry, in the realm of mixed-valence elements, can act to control physical properties, especially when complex bonding is implicated by short- and long-range ordering of structural defects. Here, solution-grown iron-oxide nanocrystals (NCs) of the pilot wüstite system are found to convert into iron-deficient rock-salt and ferro-spinel subdomains but attain a surprising tetragonally distorted local structure. Cationic vacancies within chemically uniform NCs are portrayed as the parameter to tweak the underlying properties. These lattice imperfections are shown to produce local exchange-anisotropy fields that reinforce the nanoparticles’ magnetization and overcome the influence of finite-size effects. The concept of atomic-scale defect control in subcritical-size NCs aspires to become a pathway to tailor-made properties with improved performance for hyperthermia heating over defect-free NCs

Distribution of human metapneumovirus among children presenting with acute respiratory tract infection to a General Hospital in Sri Lanka

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