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- Member of: ASU Electronic Theses and Dissertations
Description
In October, 2009, participants of the Arizona Special Supplemental Nutrition Program for Women, Infants and Children (WIC) began receiving monthly Cash Value Vouchers (CVV) worth between six and 10 dollars towards the purchase of fresh fruits and vegetables. Data from the Arizona Department of Health Services (ADHS) showed CVV redemption rates in the first two years of the program were lower than the national average of 77% redemption. In response, the ADHS WIC Food List was expanded to also include canned and frozen fruits and vegetables. More recent data from ADHS suggest that redemption rates are improving, but variably exist among different WIC sub-populations. The purpose of this project was to identify themes related to the ease or difficulty of WIC CVV use amongst different categories of low-redeeming WIC participants. A total of 8 focus groups were conducted, four at a clinic in each of two Valley cities: Surprise and Mesa. Each of the four focus groups comprised one of four targeted WIC participant categories: pregnant, postpartum, breastfeeding, and children with participation ranging from 3-9 participants per group. Using the general inductive approach, recordings of the focus groups were transcribed, hand-coded and uploaded into qualitative analysis software resulting in four emergent themes including: interactions and shopping strategies, maximizing WIC value, redemption issues, and effect of rule change. Researchers identified twelve different subthemes related to the emergent theme of interactions and strategies to improve their experience, including economic considerations during redemption. Barriers related to interactions existed that made their purchase difficult, most notably anger from the cashier and other shoppers. However, participants made use of a number of strategies to facilitate WIC purchases or extract more value out of WIC benefits, such as pooling their CVV. Finally, it appears that the fruit and vegetable rule change was well received by those who were aware of the change. These data suggest a number of important avenues for future research, including verifying these themes are important within a larger, representative sample of Arizona WIC participants, and exploring strategies to minimize barriers identified by participants, such as use of electronic benefits transfer-style cards (EBT).
ContributorsBertmann, Farryl M. W (Author) / Wharton, Christopher (Christopher Mack), 1977- (Thesis advisor) / Ohri-Vachaspati, Punam (Committee member) / Johnston, Carol (Committee member) / Hampl, Jeffrey (Committee member) / Dixit-Joshi, Sujata (Committee member) / Barroso, Cristina (Committee member) / Arizona State University (Publisher)
Created2013
Description
Light-driven reactions can replace chemical and material consumption of advanced water treatment technologies. A barrier to light-driven water treatment is optical obstructions in aquafers (i.e. granular media) or built infrastructures (i.e. tubing) that limits light propagation from a single source such as the sun, or lamps. Side emitting optical fibers (SEOFs) can increase light distribution by > 1000 X from one-point source, but absorbance of UV light by conventional optical fibers limits their application to visible light only.
This dissertation assessed how SEOFs can enable visible through ultraviolet light-driven processes to purify water. I first used an existing visible light polymer SEOF and phototrophic organisms to increase the dissolved oxygen level of a granular sand reactor to > 15 mg DO/L. The results indicated that SEOFs successfully guide light past optical obstructions for environmental remediation which encouraged the fabrication of UV-C SEOFs for microbial inactivation.
I was the first to obtain consecutive UV-C side emission from optical fibers by placing nanoparticles on the surface of a UV transmitting glass core. The nanoparticles induced side-emission via Mie scattering and interactions with the evanescent wave. The side emission intensity was modulated by tuning the separation distance between the nanoparticle and fiber surface. Coating the fiber with a UV-C transparent polymer offered the optical fiber flexibility and prevented nanoparticle release into solution. One SEOF coupled to a 265 nm LED achieved 3-log inactivation of E. coli. Finally, a method was developed to quantify the zone of inhibition obtained by a low flux output source. By placing a SEOF connected to a UV-C LED over a nutrient-rich LB agar plate, I illustrated that one SEOF inhibited the growth of P. aeruginosa and E. coli within 2.8 cm along the fiber’s length. Ultimately this research informed that side-emitting optical fibers can enable light-driven water purification by guiding and distributing specific wavelengths of light directly to the microbial communities of interest.
This dissertation assessed how SEOFs can enable visible through ultraviolet light-driven processes to purify water. I first used an existing visible light polymer SEOF and phototrophic organisms to increase the dissolved oxygen level of a granular sand reactor to > 15 mg DO/L. The results indicated that SEOFs successfully guide light past optical obstructions for environmental remediation which encouraged the fabrication of UV-C SEOFs for microbial inactivation.
I was the first to obtain consecutive UV-C side emission from optical fibers by placing nanoparticles on the surface of a UV transmitting glass core. The nanoparticles induced side-emission via Mie scattering and interactions with the evanescent wave. The side emission intensity was modulated by tuning the separation distance between the nanoparticle and fiber surface. Coating the fiber with a UV-C transparent polymer offered the optical fiber flexibility and prevented nanoparticle release into solution. One SEOF coupled to a 265 nm LED achieved 3-log inactivation of E. coli. Finally, a method was developed to quantify the zone of inhibition obtained by a low flux output source. By placing a SEOF connected to a UV-C LED over a nutrient-rich LB agar plate, I illustrated that one SEOF inhibited the growth of P. aeruginosa and E. coli within 2.8 cm along the fiber’s length. Ultimately this research informed that side-emitting optical fibers can enable light-driven water purification by guiding and distributing specific wavelengths of light directly to the microbial communities of interest.
ContributorsLanzarini-Lopes, Mariana (Author) / Westerhoff, Paul (Thesis advisor) / Alvarez, Pedro J (Committee member) / Garcia-Segura, Sergi (Committee member) / Arizona State University (Publisher)
Created2020