The solubilization of ferric iron by in vitro digests of chicken muscle proteins was studied. Non-muscle proteins (ovalbumin and casein) were similarly evaluated. The dilute salt insoluble proteins (DSIP) solubilized twice as much iron as the dilute salt soluble proteins. Most of the iron solubilized was ferrous. Only 1% of the total iron solubilized was dialyzable. Maximum iron solubilization was obtained after digestion with pepsin (3 hours) and pancreatin (0.5 hour). Ovalbumin and casein solubilized significantly (p $<$ 0.05) more iron than the DSIP. These proteins may not however enhance iron uptake in vivo. Ultrafiltration of iron-protein digests indicated that most of the iron was bound to proteins or peptides whose molecular weight (MW) was greater than 10000. However, when large (MW $>$ 10000) and small (MW $<$ 10000) peptides were separated by ultrafiltration, their total iron solubilizing capacity was similar. Ultrafiltration could be used to isolate the iron binding peptides of the DSIP fraction. Iron solubilization by DSIP was accompanied by loss of some histidyl and sulfhydryl residues. Chemical modification of each of these residues led to a decrease of about 30% in iron solubilization. Similar effects were observed with free histidine and cysteine but not with glutathione. Interaction of iron with these residues could not account for all the iron solubilized by the DSIP. It was therefore likely that residues or interactions other than these were involved in iron solubilization by the DSIP peptides. It was concluded that the DSIP digest solubilizes iron and enhances iron bioavailability by both complexation and reduction of dietary ferric iron to the more soluble ferrous form partly through its histidyl and sulfhydryl residues.

Speciation has become an important area of research in the fields of food and environmental analysis because the nutritional value and toxicity of an element depend largely on its chemical form. Elemental speciation requires an efficient separation procedure followed by elementally selective detection. Atomic plasma spectral emission spectroscopy provides powerful element-specific detection for gas chromatography (GC-AED), and today it is utilized in the only commercial available instrument which can be used for both metal and nonmetal speciation. GC-AED has the important advantage of high sensitivity, high elemental selectivity and the possibility of simultaneous multi-element analysis. The atomic emission detection response can flag compounds in the GC effluent which contain specific elements even though these compounds may be present in very small amounts or may co-elute with other components. This dissertation research has been focused on the application of different sample pre-treatment methods coupled with GC-AED for the speciation of organo-selenium in garlic, onion and broccoli. Interest in selenium has heightened in recent years concomitant with the recognition of the element's essential nutritional role, and upon reports of selenium toxicity in humans. Chemical and biochemical pathways in the natural selenium cycle are still not clear because it is very difficult to identify the form of organoselenium compounds at naturally occurring levels. Speciation of organo-selenium compounds at natural levels requires very sensitive and selective detection following an efficient separation and isolation process. Allium species, in particular garlic, have been investigated for a long time. The beneficial properties of garlic feature in the folklore of many cultures around the world. Recently, health benefits of garlic and other related plants, such as onion and broccoli, have been thought to derive from various sulfur- and perhaps selenium-containing compounds in these plants. Identification of the selenium-containing compounds has remained elusive because nature plants contain selenium at levels of less than one ppm, which are orders of magnitude lower than the levels of sulfur present. A large number of papers have been published regarding sulfur chemistry of Allium, but very little information is available on their selenium chemistry. GC-AED was used to achieve the first successful identification and determination of organoselenium compounds at natural levels in plants, these including garlic, onion, broccoli, Chinese chive and radish. Headspace-GC-AED was used to determine trace levels of volatile organoselenium compounds. This has given information on the likely enzymatic degradation of selenium compounds in natural plants. Tenax trap/cryogenic-GC-AED has been used to measure organoselenium compounds in human breath after ingestion of garlic. This has helped the understanding of selenium degradation pass ways in human beings. Another investigation has focussed upon the primarily chemical format of selenium in natural plants; derivatization-GC-AED was used for the determination of free seleno-amino acids. This dissertation also discussed the application of headspace-GC-AED for the determination of 'organo-mercury' in water. Sub-parts per trillion of alkylmercury compounds have been detected in environmental water samples. GC-AED and a membrane introduction mass spectrometer (MIMS) have been used for the study of mechanisms of enzymatic degradation in garlic, major sulfur volatiles released from garlic having been monitored. HPLC-ICP-MS has been investigated for the determination of non-volatile organo-selenium compounds. Investigation on improving the performance of GC-AED were also a part of this research.

This thesis aimed to explore gaps in existing knowledge and identify new avenues to illuminate the connections between agriculture, nutrition and environmental health. Three separate, but complimentary, studies were designed to achieve this. The findings were then used to develop a model multisector intervention approach to improve food security, nutrition, the household environment and health outcomes in low and middle-income countries (LMIC), using Nepal as a case study. This research adopted a mixed-methods sequential explanatory approach. Initially, peer reviewed journal articles were reviewed to identify the type, extent and effectiveness of household interventions to improve food security, health and the household environment in LMIC. The barriers and facilitators to the development and delivery of multisector interventions in LMIC were assessed based on the qualitative synthesis of academic journal articles and existing grey literature. Additionally, a workshop-based qualitative case study was completed to understand Nepalese stakeholders' perceptions on development and implementation of a multisector intervention. It is clear that very little trans-disciplinary research has been done with the majority of studies still being discipline specific. It also appears that certain LMIC seem to focus on domain specific interventions. Those interventions that incorporated multiple domains such as; home gardening with nutrition education; nutrition intervention with water, sanitation and hygiene; appear to be more successful in terms of providing multiple benefits. Qualitative synthesis highlighted common barriers including co-ordination issues, access to the resources, inadequate technical capacity and limited shared understanding of multidisciplinary working among sectorial stakeholders. While facilitators included collaborative networking opportunities such as discipline discourse, webinars and funding to ensure sustainability of interventions. In addition, the Nepalese case study identified gaps in terms of knowledge generation and sharing between and within sectors. Finally, findings were synthesised to develop an evidence-based model approach multisector intervention to address multifaceted public health issues in LMIC.

Dans le cadre du diagnostic de l'allergie, l'approche in vitro la plus utilisée consiste à quantifier les Immunoglobulines E (IgE) du patient par un immunodosage de type enzyme linked immunosorbent assay (ELISA) à l'aide d'un support conventionnel : la plaque de microtitration. Ces méthodes sont utilisées du fait de leur grande spécificité et sensibilité. Bien que cette technique soit facile à mettre en œuvre et automatisable, elle nécessite des volumes de réactifs et d'échantillons importants (de l'ordre de la centaine de μL) et est limitée par le transfert de masse des analytes vers la surface du support générant ainsi des temps d'analyse élevés. Notre travail a consisté à élaborer un microsystème bioanalytique intégrant des nanoparticules magnétiques et dédié au diagnostic de l'allergie au lait. Les nanoparticules magnétiques fonctionnalisées avec la molécule de capture, l'antigène dans notre cas, sont utilisées en tant que support de l'interaction et permettent ainsi de capturer la cible (IgE) en phase colloïdale. La réduction de la taille du support vers des échelles nanométriques permet d'augmenter le rapport surface sur volume et de réduire les distances de diffusion. Ainsi, la cinétique d'interaction entre la molécule de capture et la cible est accélérée par rapport à des supports milli ou micrométriques. Après l'étape de capture de la molécule cible, les nanoparticules et donc la cible sont séparées des molécules interférentes et préconcentrées au sein d'une chambre magnétique avant l'étape de détection. En effet, cette chambre magnétique, composée de billes de fer ferromagnétiques, permet le confinement magnétique des nanoparticules. Ainsi, le microsystème que nous avons développé a permis de diminuer les temps d'analyse d'un facteur 25 et de consommer 50 fois moins d'échantillon par rapport à un ELISA conventionnel réalisé en plaque de microtitration. Ceci est d'autant plus critique que l'on travaille dans un contexte d'allergie au lait qui concerne les jeunes enfants. L'immunodosage des IgE spécifiques au sein des sérums de patients allergiques au lait et la comparaison des résultats avec une méthode de référence a permis de valider ce microsystème bioanalytique en tant qu'outil de diagnostic de l'allergie.

This study qualitatively explored how students, parents and school staff perceived the role that the school food environment played in student eating behaviour, how the Food and Nutrition Policy for Nova Scotia Public Schools impacted the food environment. This study looked at one public elementary school from Nova Scotia through a focus group with 6 grade five students, and individual interviews with 6 parents and 11 school staff members. Under the constructivist paradigm, the methodology chosen was social constructionism using constant comparative analysis. Significant themes that emerged from the data included: schools have a role in children’s eating habits; school culture is important for supporting a healthy food environment; and the food brought from home is the unhealthiest part of the school food environment. This research contributes to knowledge on the school’s impact on student eating behaviour, effectiveness of the policy, and the development of future research.

Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2007. / Includes bibliographical references.

Thesis (M.A.) - Carleton University, 2005. / Includes bibliographical references (p. 82-93). Also available in electronic format on the Internet.

Thesis (M.A.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vii, 118 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 111-118).

Thesis (M.P.H)--Emory University, 2004. / "A thesis submitted to the Department of International Health, Rollins School of Public Health, Emory University, in partial fulfillment of the requirements for the degree of Master of Public Health". "August, 2004". Includes bibliographical references (p. 66-69).

Thesis--University of Wisconsin. / eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 250-254.