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Food insecurity is an economic and social condition involving limited or uncertain access to food. The problem of food insecurity in communities is influenced by economic conditions, food deserts, and barriers to accessing healthy food. Individuals experiencing food insecurity often endure concurrent problems of financial instability, hunger, and poor mental and physical health. Public and non-profit services in the U.S., such as the federally supported Supplemental Nutrition Assistance Program (SNAP) and community food banks, provide food-related assistance to individuals who are at a high risk of experiencing food insecurity. Unfortunately, many individuals who qualify for these services still experience food insecurity due to barriers preventing them from accessing food, which may include inadequate finances, transportation, skills, and information. Effective approaches for removing barriers that prevent individuals from accessing food are needed to mitigate the increased risk of hunger, nutritional deficiencies, and chronic disease among vulnerable populations. This dissertation tested a novel food insecurity intervention using informational nudges to promote food security through the elimination of information barriers to accessing food. The intervention used in this mixed-methods feasibility study consisted of informational nudges in the form of weekly text messages that were sent to food pantry clients experiencing food insecurity. The study aims were to test the efficacy and acceptability of the intervention by examining whether the informational nudges could enhance food pantry utilization, increase SNAP registration, and promote food security. Quantitative study results showed a lower prevalence of food insecurity in the intervention group than the control group. Qualitative findings revealed how the intervention group found the text messages to be helpful and informative. These study findings can enhance future food insecurity interventions aiming to eliminate barriers that prevent individuals who are food insecure from accessing healthy food.
ContributorsRoyer, Michael F. (Author) / Wharton, Christopher (Thesis advisor) / Buman, Matthew (Committee member) / Der Ananian, Cheryl (Committee member) / MacKinnon, David (Committee member) / Ohri-Vachaspati, Punam (Committee member) / Arizona State University (Publisher)
Created2023
Description
Based on the common phenomenon of style rotation in domestic and foreign stock markets, this paper aims to study and answer which factors jointly drive style rotation and whether style rotation is predictable. Based on the dividend discount model, this paper selects variables that may explain style rotation from the three dimensions of capital cost, risk premium and performance growth. At the same time, this paper innovatively introduces the capital flow variables of institutional investors and northward funds to help explain and predict style rotation from the perspective of "smart money".First, based on the A-share market, this study uses the daily frequency value factor yield data from January 1, 2015 to December 31, 2020 to carry out temporal regression of the variables that may affect the value factor yield. It is found that the macroeconomic leading indicator and Wind A dynamic dividend yield can significantly affect the yield of value factor, and the impact is positive, that is, the rise of the macroeconomic leading indicator and the rise of the dynamic dividend yield of A shares both lead to the rise of value factor yield. In addition, based on daily frequency, this paper also found that value factor yield and northbound capital scale is significantly negatively correlated, but this relationship does not exist on monthly frequency.
Secondly, this study further uses the daily frequency value factor yield data from January 1, 2015 to December 31, 2020 to carry out temporal regression of each explanatory variable of the previous day, trying to study whether these variables can predict the value factor yield. It is found that the leading macroeconomic indicator and Wind All-A dynamic dividend yield can positively predict the yield of value factor. Specifically, if the leading macroeconomic indicator rises in the previous trading day or the Wind A dynamic dividend yield rises in the previous day, on average, the value factor yield will rise in the next trading day. This finding is consistent with the results of synchronous temporal regression in the previous section. In addition, this paper does not find that the size of northbound funds can significantly predict the return rate of the value factor.
Finally, this study uses variables that have significant predictive effect on the value factor rate of return to build a model. Based on this model, the out-of-sample value factor rate of return is predicted, so as to timing the value factor. The results show that the rate of return of value factor investment strategy based on model timing is twice as high as that of long-term holding value factor.
ContributorsLiu, Shiwei (Author) / Huang, Xiaochuan (Thesis advisor) / Kan, Rui (Thesis advisor) / Wei, Li (Committee member) / Arizona State University (Publisher)
Created2024
Description
As screen time (ST) constitutes an integral part of the daily lives of young children today, parents, educators, and researchers have started to explore the associations of ST with children’s cognitive, behavioral, and social outcomes. The majority of existing studies have primarily focused on the duration of ST in relation to these outcomes despite the importance of other aspects such as content and type of device in the context of an evolving digital landscape marked by high mobility, ubiquity, and diversity. Addressing this gap, the current study aimed to explore the intricate relations between multiple aspects of ST (i.e., duration and content), executive function (EF) difficulties, and school adjustment in school-aged children, with a particular focus on the mediating role of EF difficulties linking the relations between ST and school adjustment. The current study employed data from the Panel Study on Korean Children, tracking 1,484 South Korean children from third to fourth grade. The duration of ST was measured by the average daily hours spent on smart devices and computers. Parent reports of the levels of engagement in recreational and educational ST and EF difficulties were assessed on Likert scales. School adjustment was reported on by teachers. The results from a half-longitudinal mediation model demonstrated that more frequent engagement in educational ST was related to fewer EF difficulties, which was in turn associated with better school adjustment. The current findings suggest that multiple approaches are needed to effectively guide children’s ST use in their everyday lives and interventions that target EF might be an effective way to promote children's behavioral and social adjustment in school settings.
ContributorsKim, Juyoung (Author) / Tsethlikai, Monica (Thesis advisor) / Buman, Matthew (Committee member) / Eggum, Natalie (Committee member) / Valiente, Carlos (Committee member) / Arizona State University (Publisher)
Created2024
Description
No studies have evaluated the impact of tracking resting energy expenditure (REE) and modifiable health behaviors on gestational weight gain (GWG). In this controlled trial, pregnant women aged >18 years (X=29.8±4.9 years) with a gestational age (GA) <17 weeks were randomized to Breezing™ (N=16) or control (N=12) for 13 weeks. The Breezing™ group used a real-time metabolism tracker to obtain REE. Anthropometrics, diet, and sleep data were collected every 2 weeks. Rate of GWG was calculated as weight gain divided by total duration. Early (GA weeks 14-21), late (GA weeks 21-28), and overall (GA week 14-28) changes in macronutrients, sleep, and GWG were calculated. Mediation models were constructed using SPSS PROCESS macro using a bootstrap estimation approach with 10,000 samples. The majority of women were non-Hispanic Caucasian (78.6%). A total of 35.7% (n=10), 35.7% (n=10), and 28.6% (n=8) were normal weight, overweight, and obese, respectively, with 83.3% (n=10) and 87.5% (n=14) of the Control and Breezing™ groups gaining above IOM GWG recommendations. At baseline, macronutrient consumption did not differ. Overall (Breezing™ vs. Control; M diff=-349.08±150.77, 95% CI: -660.26 to -37.90, p=0.029) and late (M diff=-379.90±143.89, 95% CI:-676.87 to -82.93, p=0.014) changes in energy consumption significantly differed between the groups. Overall (M diff=-22.45±11.03, 95% CI: -45.20 to 0.31, p=0.053), late (M diff=-23.16±11.23, 95% CI: -46.33 to 0.01, p=0.05), and early (M diff=20.3±10.19, 95% CI: -0.74 to 41.34, p=0.058) changes in protein differed by group. Nocturnal total sleep time differed by study group (Breezing vs. Control; M diff=-32.75, 95% CI: -68.34 to 2.84, p=0.069). There was a 11.5% increase in total REE throughout the study. Early changes in REE (72±211 kcals) were relatively small while late changes (128±294 kcals) nearly doubled. Interestingly, early changes in REE demonstrated a moderate, positive correlation with rates of GWG later in pregnancy (r=0.528, p=0.052), suggesting that REE assessment early in pregnancy may help predict changes in GWG. Changes in macronutrients did not mediate the relationship between the intervention and GWG, nor did sleep mediate relationships between dietary intake and GWG. Future research evaluating REE and dietary composition throughout pregnancy may provide insight for appropriate GWG recommendations.
ContributorsVander Wyst, Kiley Bernhard (Author) / Whisner, Corrie M (Thesis advisor) / Reifsnider, Elizabeth G. (Committee member) / Petrov, Megan E (Committee member) / Buman, Matthew (Committee member) / Shaibi, Gabriel Q (Committee member) / Arizona State University (Publisher)
Created2019
Description
Antibodies are naturally occurring proteins that protect a host during infection through direct neutralization and/or recruitment of the innate immune system. Unfortunately, in some infections, antibodies present unique hurdles that must be overcome for a safer and more efficacious antibody-based therapeutic (e.g., antibody dependent viral enhancement (ADE) and inflammatory pathology). This dissertation describes the utilization of plant expression systems to produce N-glycan specific antibody-based therapeutics for Dengue Virus (DENV) and Chikungunya Virus (CHIKV). The Fc region of an antibody interacts with Fcγ Receptors (FcγRs) on immune cells and components of the innate immune system. Each class of immune cells has a distinct action of neutralization (e.g., antibody dependent cell-mediated cytotoxicity (ADCC) and antibody dependent cell-mediated phagocytosis (ADCP)). Therefore, structural alteration of the Fc region results in novel immune pathways of protection. One approach is to modulate the N-glycosylation in the Fc region of the antibody. Of scientific significance, is the plant’s capacity to express human antibodies with homogenous plant and humanized N-glycosylation (WT and GnGn, respectively). This allows to study how specific glycovariants interact with other components of the immune system to clear an infection, producing a tailor-made antibody for distinct diseases. In the first section, plant-produced glycovariants were explored for reduced interactions with specific FcγRs for the overall reduction in ADE for DENV infections. The results demonstrate a reduction in ADE of our plant-produced monoclonal antibodies in in vitro experiments, which led to a greater survival in vivo of immunodeficient mice challenged with lethal doses of DENV and a sub-lethal dose of DENV in ADE conditions. In the second section, plant-produced glycovariants were explored for increased interaction with specific FcγRs to improve ADCC in the treatment of the highly inflammatory CHIKV. The results demonstrate an increase ADCC activity in in vitro experiments and a reduction in CHIKV-associated inflammation in in vivo mouse models. Overall, the significance of this dissertation is that it can provide a treatment for DENV and CHIKV; but equally importantly, give insight to the role of N-glycosylation in antibody effector functions, which has a broader implication for therapeutic development for other viral infections.
ContributorsHurtado, Jonathan (Author) / Chen, Qiang (Thesis advisor) / Arntzen, Charles (Committee member) / Borges, Chad (Committee member) / Lake, Douglas (Committee member) / Arizona State University (Publisher)
Created2019
Description
This study examines cognitive and motor function in typical older adults following acute exercise. Ten older adults (Mage = 65.1) completed a single session of assisted cycling (AC) (i.e., exercise accomplished through the use of a motor), voluntary cycling (VC) (self-selected cadence), and a no cycling (NC) control group. These sessions were randomized and separated by approximately one week. Both ACT and VC groups rode a stationary bicycle for 30-minutes each session. These sessions were separated by at least two days. Participants completed cognitive testing that assessed information processing and set shifting and motor testing including gross and fine motor performance at the beginning and at the end of each session. Consistent with our hypothesis concerning manual dexterity, the results showed that manual dexterity improved following the ACT session more than the VC or NC sessions. Improvements in set shifting were also found for the ACT session but not for the VC or NC sessions. The results are interpreted with respect to improvements in neurological function in older adults following acute cycling exercise. These improvements are balance, manual dexterity, and set shifting which have a positive effects on activities of daily living; such as, decrease risk of falls, improve movements like eating and handwriting, and increase ability to multitask.
ContributorsSemken, Keith (Author) / Ringenbach, Shannon (Thesis advisor) / Der Ananian, Cheryl (Committee member) / Buman, Matthew (Committee member) / Arizona State University (Publisher)
Created2015
Description
PURPOSE: Lean hypertension (HTN) is characterized by a mechanistically different HTN when compared to obese HTN. The purpose of this study is to assess whether body phenotype influences blood pressure (BP) responses following both acute and chronic exercise. METHODS: Obese (body mass index (BMI) > 30 kg/m2) and lean (BMI < 25 kg/m2) men with pre-hypertension (PHTN) (systolic BP (SBP) 120 - 139 or diastolic BP (DBP) 80 - 89 mm Hg) were asked to participate in a two-phase trial. Phase 1 assessed differences in post-exercise hypotension between groups in response to an acute exercise bout. Phase 2 consisted of a two-week aerobic exercise intervention at 65-70% of heart rate (HR) max on a cycle ergometer. Primary outcome measures were: brachial BP, central (aortic) BP, cardiac output (CO), and systemic vascular resistance (SVR) measured acutely after one exercise session and following two weeks of training. RESULTS: There were no differences between groups for baseline resting brachial BP, central BP, age, or VO2 peak (all P > 0.05). At rest, obese PHTN had greater CO compared to lean PHTN (6.3 ± 1 vs 4.7 ± 1 L/min-1, P = 0.005) and decreased SVR compared to lean PHTN (1218 ± 263 vs 1606 ± 444 Dyn.s/cm5, P = 0.003). Average 60-minute post-exercise brachial and central SBP reduced by 3 mm Hg in Lean PHTN in response to acute exercise (P < 0.005), while significantly increasing 4 mm Hg for brachial and 3 mm Hg for central SBP (P < 0.05). SVR had a significantly greater reduction following acute exercise in lean PHTN (-223 Dyn·s/cm5) compared to obese PHTN (-75 Dyn·s/cm5, P < 0.001). In lean subjects chronic training reduced brachial BP by 4 mm Hg and central BP by 3 mm Hg but training had no effect on the BP’s in obese subjects. Resting BP reduction in response to training was accompanied by reductions in SVR within lean (-169 Dyn·s/cm5, P < 0.001), while obese experienced increased SVR following training (47 Dyn·s/cm5, P < 0.001). CONCLUSION: Hemodynamic response to both acute and chronic exercise training differ between obese and lean individuals.
ContributorsZeigler, Zachary (Author) / Swan, Pamela (Thesis advisor) / Gaesser, Glenn (Committee member) / Buman, Matthew (Committee member) / Angadi, Siddhartha (Committee member) / Farouk, Mookadam (Committee member) / Arizona State University (Publisher)
Created2016
Description
The purpose of this study was to examine whether a workplace environmental intervention would improve work-related outcomes including productivity, presenteeism and cognition. The secondary aim was to investigate whether work-related outcomes are correlated to observed changes in sitting time, physical activity, and sleep. The study was introduced as part of a naturalistic environmental change in which university staff and faculty were relocated into a new building (n=23). The comparison group consisted of university staff within the same college with no imminent plans to re-locate during the intervention period; there were no environmental changes to this workplace (n =10). Participants wore two behavioral monitoring devices, activPAL and GeneActiv, for 7 consecutive days at two time points (immediately prior and 16 weeks following the office relocation). Measures of productivity and presenteeism were obtained via four validated questionnaires and participants underwent cognitive performance testing. Baseline adjusted analysis of covariance statistical analyses were used to examine differences between groups in work-related outcomes. A residual analysis in regression was conducted to determine the differences between observed changes in sitting time, physical activity and sleep, and work-related outcomes. The results showed that a reduction in work hour sitting time was not detrimental to work related outcomes. Decreased sitting was observed to potentially improve presenteeism and absenteeism. Additionally, physical activity was shown to modestly improve productivity, presenteeism and absenteeism. Poor sleep patterns were associated with work impairment and increased absenteeism.
ContributorsPark, Anna (Author) / Buman, Matthew (Thesis advisor) / Crespo, Noe (Committee member) / Chisum, Jack (Committee member) / Arizona State University (Publisher)
Created2014
Description
Flavivirus infections are emerging as significant threats to human health around the globe. Among them West Nile(WNV) and Dengue Virus (DV) are the most prevalent in causing human disease with WNV outbreaks occurring in all areas around the world and DV epidemics in more than 100 countries. WNV is a neurotropic virus capable of causing meningitis and encephalitis in humans. Currently, there are no therapeutic treatments or vaccines available. The expanding epidemic of WNV demands studies that develop efficacious therapeutics and vaccines and produce them rapidly and inexpensively. In response, our lab developed a plant-derived monoclonal antibody (mAb) (pHu-E16) against DIII (WNV antigen) that is able to neutralize and prevent mice from lethal infection. However, this drug has a short window of efficacy due to pHu-E16's inability to cross the Blood Brain Barrier (BBB) and enter the brain. Here, we constructed a bifunctional diabody, which couples the neutralizing activity of E16 and BBB penetrating activity of 8D3 mAb. We also produced a plant-derived E16 scFv-CH1-3 variant with equivalent specific binding as the full pHu-E16 mAb, but only requiring one gene construct for production. Furthermore, a WNV vaccine based on plant-derived DIII was developed showing proper folding and potentially protective immune response in mice. DV causes severe hemorrhaging diseases especially in people exposed to secondary DV infection from a heterotypic strain. It is hypothesized that sub-neutralizing cross-reactive antibodies from the first exposure aid the second infection in a process called antibody-dependent enhancement (ADE). ADE depends on the ability of mAb to bind Fc receptors (FcγRs), and has become a major roadblock for developing mAb-based therapeutics against DV. We aim to produce an anti-Dengue mAb (E60) in different glycoengineered plant lines that exhibit reduced/differential binding to FcγRs, therefore, reducing or eliminating ADE. We have successfully cloned the molecular constructs of E60, and expressed it in two plant lines with different glycosylation patterns. We demonstrated that both plant-derived E60 mAb glycoforms retained specific recognition and neutralization activity against DV. Overall, our study demonstrates great strives to develop efficacious therapeutics and potent vaccine candidates against Flaviviruses in plant expression systems.
ContributorsHurtado, Jonathan (Author) / Chen, Qiang (Thesis advisor) / Huffman, Holly A (Committee member) / Steele, Kelly P (Committee member) / Arizona State University (Publisher)
Created2014
Description
Background and purpose: Regular physical activity (PA) provides benefits for cognitive health and helps to improve or maintain quality of life among older adults. Objective PA measures have been increasingly used to overcome limitations of self-report measures. The purpose of this study was to investigate the association of objectively measured PA and sedentary time with cognitive function among older adults.
Methods: Participants were recruited from the parent REasons for Geographic and Racial Differences in Stroke (REGARDS) Study. ActicalTM accelerometers provided estimates of PA variables, including moderate-to-vigorous PA (MVPA), high light PA (HLPA), low light PA (LLPA) and sedentary time, for 4-7 consecutive days. Prevalence and incidence of cognitive impairment were defined by the Six-Item Screener. Letter fluency, animal fluency, word list learning and Montreal Cognitive Assessment (orientation and recall) were conducted to assess executive function and memory.
Results: Of the 7,339 participants who provided accelerometer wear data > 4 days (70.1 ± 8.6 yr, 54.2% women, 31.7% African American), 320 participants exhibited impaired cognition. In cross-sectional analysis, participants in the highest MVPA% quartile had 39% lower odds of cognitive impairment than those in the lowest quartile (OR: 0.61, 95% C.I.: 0.39-0.95) after full adjustment. Further analysis shows most quartiles of MVPA% and HLPA% were significantly associated with executive function and memory (P<0.01). During 2.7 ± 0.5 years of follow-up, 3,385 participants were included in the longitudinal analysis, with 157 incident cases of cognitive impairment. After adjustments, participants in the highest MVPA% quartile had 51% lower hazards of cognitive impairment (HR: 0.49, 95% C.I.: 0.28-0.86). Additionally, MVPA% was inversely associated with change in memory z-scores (P<0.01), while the highest quartile of HLPA% was inversely associated with change in executive function and memory z-scores (P<0.01).
Conclusion: Higher levels of objectively measured MVPA% were independently associated with lower prevalence and incidence of cognitive impairment, and better memory and executive function in older adults. Higher levels of HLPA% were also independently associated with better memory and executive function. The amount of MVPA associated with lower risk of cognitive impairment (259 min/week) is >70% higher than the minimal amount of MVPA recommended by PA guidelines.
Methods: Participants were recruited from the parent REasons for Geographic and Racial Differences in Stroke (REGARDS) Study. ActicalTM accelerometers provided estimates of PA variables, including moderate-to-vigorous PA (MVPA), high light PA (HLPA), low light PA (LLPA) and sedentary time, for 4-7 consecutive days. Prevalence and incidence of cognitive impairment were defined by the Six-Item Screener. Letter fluency, animal fluency, word list learning and Montreal Cognitive Assessment (orientation and recall) were conducted to assess executive function and memory.
Results: Of the 7,339 participants who provided accelerometer wear data > 4 days (70.1 ± 8.6 yr, 54.2% women, 31.7% African American), 320 participants exhibited impaired cognition. In cross-sectional analysis, participants in the highest MVPA% quartile had 39% lower odds of cognitive impairment than those in the lowest quartile (OR: 0.61, 95% C.I.: 0.39-0.95) after full adjustment. Further analysis shows most quartiles of MVPA% and HLPA% were significantly associated with executive function and memory (P<0.01). During 2.7 ± 0.5 years of follow-up, 3,385 participants were included in the longitudinal analysis, with 157 incident cases of cognitive impairment. After adjustments, participants in the highest MVPA% quartile had 51% lower hazards of cognitive impairment (HR: 0.49, 95% C.I.: 0.28-0.86). Additionally, MVPA% was inversely associated with change in memory z-scores (P<0.01), while the highest quartile of HLPA% was inversely associated with change in executive function and memory z-scores (P<0.01).
Conclusion: Higher levels of objectively measured MVPA% were independently associated with lower prevalence and incidence of cognitive impairment, and better memory and executive function in older adults. Higher levels of HLPA% were also independently associated with better memory and executive function. The amount of MVPA associated with lower risk of cognitive impairment (259 min/week) is >70% higher than the minimal amount of MVPA recommended by PA guidelines.
ContributorsZhu, Wenfei (Author) / Hooker, Steven P (Thesis advisor) / Wadley, Virginia (Committee member) / Ainsworth, Barbara (Committee member) / Der Ananian, Cheryl (Committee member) / Buman, Matthew (Committee member) / Arizona State University (Publisher)
Created2015