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A description of numerical and analytical work pertaining to models that describe the growth and progression of glioblastoma multiforme (GBM), an aggressive form of primary brain cancer. Two reaction-diffusion models are used: the Fisher-Kolmogorov-Petrovsky-Piskunov equation and a 2-population model that divides the tumor into actively proliferating and quiescent (or necrotic) cells. The numerical portion of this work (chapter 2) focuses on simulating GBM expansion in patients undergoing treatment for recurrence of tumor following initial surgery. The models are simulated on 3-dimensional brain geometries derived from magnetic resonance imaging (MRI) scans provided by the Barrow Neurological Institute. The study consists of 17 clinical time intervals across 10 patients that have been followed in detail, each of whom shows significant progression of tumor over a period of 1 to 3 months on sequential follow up scans. A Taguchi sampling design is implemented to estimate the variability of the predicted tumors to using 144 different choices of model parameters. In 9 cases, model parameters can be identified such that the simulated tumor contains at least 40 percent of the volume of the observed tumor. In the analytical portion of the paper (chapters 3 and 4), a positively invariant region for our 2-population model is identified. Then, a rigorous derivation of the critical patch size associated with the model is performed. The critical patch (KISS) size is the minimum habitat size needed for a population to survive in a region. Habitats larger than the critical patch size allow a population to persist, while smaller habitats lead to extinction. The critical patch size of the 2-population model is consistent with that of the Fisher-Kolmogorov-Petrovsky-Piskunov equation, one of the first reaction-diffusion models proposed for GBM. The critical patch size may indicate that GBM tumors have a minimum size depending on the location in the brain. A theoretical relationship between the size of a GBM tumor at steady-state and its maximum cell density is also derived, which has potential applications for patient-specific parameter estimation based on magnetic resonance imaging data.
ContributorsHarris, Duane C. (Author) / Kuang, Yang (Thesis advisor) / Kostelich, Eric J. (Thesis advisor) / Preul, Mark C. (Committee member) / Crook, Sharon (Committee member) / Gardner, Carl (Committee member) / Arizona State University (Publisher)
Created2023
Description
The winter holiday period has been highlighted as a major risk period for weight gain due to excess caloric intake in the form of fat and sugar. Furthermore, diets high in fat and sugar have been implicated in the pathogenesis of diabetes and cardiovascular disease. Exercise aids in the prevention of weight/fat gain, and prevents deleterious changes in cardiometabolic function. The objective of this study was to examine the effects of a fat-sugar supplemented diet, with and without two different exercise training protocols, on body composition, glycemic control and other markers of cardiovascular disease in an at-risk population of overweight and obese males. Twenty-seven, healthy overweight/obese (BMI >25 kg/m2) males were fed 2 donuts per day, 6 days/week, for four weeks, while maintaining their current diet. In addition, all subjects were randomized to one of the following conditions: sedentary control, 1,000 kcal/week moderate-intensity continuous training (MICT) (50% of peak oxygen consumption), or 1,000 kcal/week high-intensity interval training (HIIT) (90-95% of peak heart rate). Supervised exercise training was performed 4 days/week on a cycle ergometer. Changes in body weight and composition, endothelial function, arterial stiffness, glycemic control, blood lipids and cardiorespiratory fitness (CRF) were assessed before and after the intervention. Body weight, lean mass and visceral fat increased significantly in HIIT (p<0.05) and were unchanged in MICT. There was a trend for a significant increase in body weight (p=0.07) and lean mass (p=0.11) in control. Glycemic control during the 2-h OGTT improved significantly in MICT and control, with no change in HIIT. Hepatic insulin resistance index (IRI) and 30-min insulin during the OGTT improved significantly after MICT and worsened following control (p=0.03), while HIIT was unchanged. CRF increased significantly in both HIIT and MICT, with no change in control (p<0.001). There were no significant changes in other markers of cardiovascular disease. The addition of a fat-sugar supplement (~14,500 kcal) over a 4-week period was not sufficient to induce deleterious changes in body composition and cardiometabolic health in overweight/obese young males. Exercise training did not afford overweight/obese males additional health benefits, with the exception of improvements in fitness and hepatic IRI.
ContributorsTucker, Wesley Jack (Author) / Gaesser, Glenn A (Thesis advisor) / Angadi, Siddhartha S (Committee member) / Whisner, Corrie M (Committee member) / Buman, Matthew P (Committee member) / Shaibi, Gabriel (Committee member) / Arizona State University (Publisher)
Created2016
Description
Background: Latinos have disproportionately high rates of obesity and type 2 diabetes. Family-based interventions may reduce chronic disease risk among Latinos across generations.
Purpose: To assess the efficacy of Athletes for Life (AFL), a 12-week community-and-family-based behavioral intervention, for improving diet, physical activity (PA), anthropometrics, fitness, and biochemical outcomes among mostly Latino parents.
Methods: Parents with at least one child 6-11 years of age were randomized to active AFL participation (n=14) or a wait-list control (n=14) group. AFL consisted of twice weekly 90 minute sessions (45 minutes of nutrition-focused lessons and 45 minutes of PA participation) designed to promote fruit and vegetable consumption, reduction of sugar intake, and increasing habitual PA. Data were collected prior to and immediately after the 12 week intervention.
Results: Participants (37.9±7.2y) were mostly Latino (93%), Spanish speaking (68%), and women (93%). Relative to participants in the control group, AFL participants had a significant reduction in body fat (-1.1±1.2% vs. 0.2±1.2%; p=0.014), resting (-7.6±10.2 bpm vs. +2.1±6.8 bpm; p<0.01), exercise (-8.4±8.7 bpm vs. +0.4±7.3 bpm; p<0.01), and recovery heart rate (-11.9±12.8 bpm vs. -0.3±11.4 bpm; p=0.01), and one mile run time (-1.5±1.0 min vs. -0.1±0.9 min; p<0.01), and a significant increase in estimated VO2 peak (+1.9±1.9 ml/kg/min vs. 0.0±1.8 ml/kg/min; p=0.01). AFL participants also reported an increase in the number of days/week accumulating 30 minutes of MVPA (+0.8±3.2 vs. -1.5±2.3; p=0.004) and daily servings of fruits (+1.3±1.4 vs. +0.3±1.4; p<0.05) and vegetables (+1.8±1.7 vs. +0.1±1.2; p<0.05), relative to control participants. There were no significant differences between groups in changes in diet assessed by 3-day food record, accelerometer-measured PA, weight, blood pressure, visceral fat, biomarkers for cardiovascular disease or nutritional biomarkers.
Conclusions: Despite the lack of effects on diet and PA behaviors, AFL shows promising preliminary efficacy for reducing body fat and improving fitness among adult participants. Future research aimed at improving fitness among Latino parents with family-based intervention is warranted.
Purpose: To assess the efficacy of Athletes for Life (AFL), a 12-week community-and-family-based behavioral intervention, for improving diet, physical activity (PA), anthropometrics, fitness, and biochemical outcomes among mostly Latino parents.
Methods: Parents with at least one child 6-11 years of age were randomized to active AFL participation (n=14) or a wait-list control (n=14) group. AFL consisted of twice weekly 90 minute sessions (45 minutes of nutrition-focused lessons and 45 minutes of PA participation) designed to promote fruit and vegetable consumption, reduction of sugar intake, and increasing habitual PA. Data were collected prior to and immediately after the 12 week intervention.
Results: Participants (37.9±7.2y) were mostly Latino (93%), Spanish speaking (68%), and women (93%). Relative to participants in the control group, AFL participants had a significant reduction in body fat (-1.1±1.2% vs. 0.2±1.2%; p=0.014), resting (-7.6±10.2 bpm vs. +2.1±6.8 bpm; p<0.01), exercise (-8.4±8.7 bpm vs. +0.4±7.3 bpm; p<0.01), and recovery heart rate (-11.9±12.8 bpm vs. -0.3±11.4 bpm; p=0.01), and one mile run time (-1.5±1.0 min vs. -0.1±0.9 min; p<0.01), and a significant increase in estimated VO2 peak (+1.9±1.9 ml/kg/min vs. 0.0±1.8 ml/kg/min; p=0.01). AFL participants also reported an increase in the number of days/week accumulating 30 minutes of MVPA (+0.8±3.2 vs. -1.5±2.3; p=0.004) and daily servings of fruits (+1.3±1.4 vs. +0.3±1.4; p<0.05) and vegetables (+1.8±1.7 vs. +0.1±1.2; p<0.05), relative to control participants. There were no significant differences between groups in changes in diet assessed by 3-day food record, accelerometer-measured PA, weight, blood pressure, visceral fat, biomarkers for cardiovascular disease or nutritional biomarkers.
Conclusions: Despite the lack of effects on diet and PA behaviors, AFL shows promising preliminary efficacy for reducing body fat and improving fitness among adult participants. Future research aimed at improving fitness among Latino parents with family-based intervention is warranted.
ContributorsChavez, Adrian (Author) / Vega-Lopez, Sonia (Thesis advisor) / Crespo, Noe (Committee member) / Hekler, Eric (Committee member) / Shaibi, Gabriel (Committee member) / Bruening, Meg (Committee member) / Arizona State University (Publisher)
Created2015
Description
In this thesis, I present the study of nucleon structure from distinct perspectives. I start by elaborating the motivations behind the endeavors and then introducing the key concept, namely the generalized parton distribution functions (GPDs), which serves as the frame- work describing hadronic particles in terms of their fundamental constituents. The second chapter is then devoted to a detailed phenomenological study of the Virtual Compton Scattering (VCS) process, where a more comprehensive parametrization is suggested. In the third chapter, the renormalization kernels that enters the QCD evolution equations at twist- 4 accuracy are computed in terms of Feynman diagrams in momentum space, which can be viewed as an extension of the work by Bukhvostov, Frolov, Lipatov, and Kuraev (BKLK). The results can be used for determining the QCD background interaction for future precision measurements.
ContributorsJi, Yao, Ph. D (Author) / Belitsky, Andrei (Thesis advisor) / Lebed, Richard (Committee member) / Schmidt, Kevin E (Committee member) / Vachaspati, Tanmay (Committee member) / Arizona State University (Publisher)
Created2016
Description
The work presented in this dissertation examines three different nonequilibrium particle physics processes that could play a role in answering the question “how was the particle content of today’s universe produced after the big bang?” Cosmic strings produced from spontaneous breaking of a hidden sector $U(1)_{\rm X}$ symmetry could couple to Standard Model fields through Higgs Portal or Kinetic Mixing operators and radiate particles that contribute to the diffuse gamma ray background. In this work we calculate the properties of these strings, including finding effective couplings between the strings and Standard Model fields. Explosive particle production after inflation, known as preheating, would have produced a stochastic background of gravitational waves (GW). This work shows how the presence of realistic additional fields and interactions can affect this prediction dramatically. Specifically, it considers the inflaton to be coupled to a light scalar field, and shows that even a very small quartic self-interaction term will reduce the amplitude of the gravitational wave spectrum. For self-coupling $\lambda_{\chi} \gtrsim g^2$, where $g^2$ is the inflaton-scalar coupling, the peak energy density goes as $\Omega_{\rm GW}^{(\lambda_{\chi})} / \Omega_{\rm GW}^{(\lambda_{\chi}=0)} \sim (g^2/\lambda_{\chi})^{2}$. Finally, leptonic charge-parity (CP) violation could be an important clue to understanding the origin of our universe's matter-antimatter asymmetry, and long-baseline neutrino oscillation experiments in the coming decade may uncover this. The CP violating effects of a possible fourth ``sterile" neutrino can interfere with the usual three neutrinos; this work shows how combinations of various measurements can help break those degeneracies.
ContributorsHyde, Jeffrey Morgan (Author) / Vachaspati, Tanmay (Thesis advisor) / Easson, Damien (Committee member) / Belitsky, Andrei (Committee member) / Comfort, Joseph (Committee member) / Arizona State University (Publisher)
Created2016
Description
Nationally, African Americans suffer disproportionately from diabetes; with 13.2% of African Americans diagnosed with diabetes compared to 7.6% of non-Hispanic whites (CDC, 2014). Nearly one-half of all people with diabetes are non-adherent to their oral medications; adherence to insulin therapy was 60%-80% (Brunton et al., 2011; Cramer, 2004; Rubin, 2005). This study explored the question, "What mechanisms are associated with adherence to diabetes medication, including insulin, for African Americans in the Southwest?" Twenty-three people participated in the study; 17 participated in interviews and six participated in gendered focus groups. A community-based participatory research (CBPR) approach engaged the African American community as partners in research.
Major themes emerging from the data included illness perception, support, and the process of medication adherence. Acceptance of the diabetes diagnosis was imperative for medication adherence. Stigmatization of diabetes was salient in the recruitment process and as it related to mechanisms for adherence. Furthermore, many informants were not aware of a family history of diabetes before their own diagnosis. Four gendered emerging typologies were identified, which further illuminated major themes. Moreover, an eight-step process of medication adherence model is discussed. The researcher was able to identify culturally compatible strategies that may be extended to those struggling with medication adherence. The implications section suggests a set of strategies that healthcare providers can present to people with diabetes in order to increase medication adherence.
Major themes emerging from the data included illness perception, support, and the process of medication adherence. Acceptance of the diabetes diagnosis was imperative for medication adherence. Stigmatization of diabetes was salient in the recruitment process and as it related to mechanisms for adherence. Furthermore, many informants were not aware of a family history of diabetes before their own diagnosis. Four gendered emerging typologies were identified, which further illuminated major themes. Moreover, an eight-step process of medication adherence model is discussed. The researcher was able to identify culturally compatible strategies that may be extended to those struggling with medication adherence. The implications section suggests a set of strategies that healthcare providers can present to people with diabetes in order to increase medication adherence.
ContributorsWardian, Jana (Author) / Marsiglia, Flavio F (Thesis advisor) / Sun, Fei (Committee member) / Shaibi, Gabriel (Committee member) / Arizona State University (Publisher)
Created2015
Description
Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by progressive autoimmune destruction of insulin-producing pancreatic β-cells. Genetic, immunological and environmental factors contribute to T1D development. The focus of this dissertation is to track the humoral immune response in T1D by profiling autoantibodies (AAbs) and anti-viral antibodies using an innovative protein array platform called Nucleic Acid Programmable Protein Array (NAPPA).
AAbs provide value in identifying individuals at risk, stratifying patients with different clinical courses, improving our understanding of autoimmune destructions, identifying antigens for cellular immune response and providing candidates for prevention trials in T1D. A two-stage serological AAb screening against 6,000 human proteins was performed. A dual specificity tyrosine-phosphorylation-regulated kinase 2 (DYRK2) was validated with 36% sensitivity at 98% specificity by an orthogonal immunoassay. This is the first systematic screening for novel AAbs against large number of human proteins by protein arrays in T1D. A more comprehensive search for novel AAbs was performed using a knowledge-based approach by ELISA and a screening-based approach against 10,000 human proteins by NAPPA. Six AAbs were identified and validated with sensitivities ranged from 16% to 27% at 95% specificity. These two studies enriched the T1D “autoantigenome” and provided insights into T1D pathophysiology in an unprecedented breadth and width.
The rapid rise of T1D incidence suggests the potential involvement of environmental factors including viral infections. Sero-reactivity to 646 viral antigens was assessed in new-onset T1D patients. Antibody positive rate of EBV was significantly higher in cases than controls that suggested a potential role of EBV in T1D development. A high density-NAPPA platform was demonstrated with high reproducibility and sensitivity in profiling anti-viral antibodies.
This dissertation shows the power of a protein-array based immunoproteomics approach to characterize humoral immunoprofile against human and viral proteomes. The identification of novel T1D-specific AAbs and T1D-associated viruses will help to connect the nodes in T1D etiology and provide better understanding of T1D pathophysiology.
AAbs provide value in identifying individuals at risk, stratifying patients with different clinical courses, improving our understanding of autoimmune destructions, identifying antigens for cellular immune response and providing candidates for prevention trials in T1D. A two-stage serological AAb screening against 6,000 human proteins was performed. A dual specificity tyrosine-phosphorylation-regulated kinase 2 (DYRK2) was validated with 36% sensitivity at 98% specificity by an orthogonal immunoassay. This is the first systematic screening for novel AAbs against large number of human proteins by protein arrays in T1D. A more comprehensive search for novel AAbs was performed using a knowledge-based approach by ELISA and a screening-based approach against 10,000 human proteins by NAPPA. Six AAbs were identified and validated with sensitivities ranged from 16% to 27% at 95% specificity. These two studies enriched the T1D “autoantigenome” and provided insights into T1D pathophysiology in an unprecedented breadth and width.
The rapid rise of T1D incidence suggests the potential involvement of environmental factors including viral infections. Sero-reactivity to 646 viral antigens was assessed in new-onset T1D patients. Antibody positive rate of EBV was significantly higher in cases than controls that suggested a potential role of EBV in T1D development. A high density-NAPPA platform was demonstrated with high reproducibility and sensitivity in profiling anti-viral antibodies.
This dissertation shows the power of a protein-array based immunoproteomics approach to characterize humoral immunoprofile against human and viral proteomes. The identification of novel T1D-specific AAbs and T1D-associated viruses will help to connect the nodes in T1D etiology and provide better understanding of T1D pathophysiology.
ContributorsBian, Xiaofang (Author) / LaBaer, Joshua (Thesis advisor) / Mandarino, Lawrence (Committee member) / Chang, Yung (Committee member) / Arizona State University (Publisher)
Created2015
Description
With the discovery of the Higgs Boson in 2012, particle physics has decidedly moved beyond the Standard Model into a new epoch. Though the Standard Model particle content is now completely accounted for, there remain many theoretical issues about the structure of the theory in need of resolution. Among these is the hierarchy problem: since the renormalized Higgs mass receives quadratic corrections from a higher cutoff scale, what keeps the Higgs boson light? Many possible solutions to this problem have been advanced, such as supersymmetry, Randall-Sundrum models, or sub-millimeter corrections to gravity. One such solution has been advanced by the Lee-Wick Standard Model. In this theory, higher-derivative operators are added to the Lagrangian for each Standard Model field, which result in propagators that possess two physical poles and fall off more rapidly in the ultraviolet regime. It can be shown by an auxiliary field transformation that the higher-derivative theory is identical to positing a second, manifestly renormalizable theory in which new fields with opposite-sign kinetic and mass terms are found. These so-called Lee-Wick fields have opposite-sign propagators, and famously cancel off the quadratic divergences that plague the renormalized Higgs mass. The states in the Hilbert space corresponding to Lee-Wick particles have negative norm, and implications for causality and unitarity are examined.
This dissertation explores a variant of the theory called the N = 3 Lee-Wick
Standard Model. The Lagrangian of this theory features a yet-higher derivative operator, which produces a propagator with three physical poles and possesses even better high-energy behavior than the minimal Lee-Wick theory. An analogous auxiliary field transformation takes this higher-derivative theory into a renormalizable theory with states of alternating positive, negative, and positive norm. The phenomenology of this theory is examined in detail, with particular emphasis on the collider signatures of Lee-Wick particles, electroweak precision constraints on the masses that the new particles can take on, and scenarios in early-universe cosmology in which Lee-Wick particles can play a significant role.
This dissertation explores a variant of the theory called the N = 3 Lee-Wick
Standard Model. The Lagrangian of this theory features a yet-higher derivative operator, which produces a propagator with three physical poles and possesses even better high-energy behavior than the minimal Lee-Wick theory. An analogous auxiliary field transformation takes this higher-derivative theory into a renormalizable theory with states of alternating positive, negative, and positive norm. The phenomenology of this theory is examined in detail, with particular emphasis on the collider signatures of Lee-Wick particles, electroweak precision constraints on the masses that the new particles can take on, and scenarios in early-universe cosmology in which Lee-Wick particles can play a significant role.
ContributorsTerBeek, Russell Henry (Author) / Lebed, Richard F (Thesis advisor) / Alarcon, Ricardo (Committee member) / Belitsky, Andrei (Committee member) / Chamberlin, Ralph (Committee member) / Parikh, Maulik (Committee member) / Arizona State University (Publisher)
Created2015
Description
Type 1 diabetes (T1D) is one of the most common chronic diseases in youth and it has been shown that adolescents have the worst glycemic control of any age group. The objective of this study was to develop, test and evaluate the feasibility of an online intervention (Can-Do-Tude) that uses the principles of motivational interviewing (MI) to deliver tailored diabetes self-management education to adolescents with T1D. Bandura’s efficacy belief system was used to guide the design of this study.
The study used a multi-phase, multi-method approach. The first phase (alpha) of this study was a qualitative descriptive design to examine the intervention’s fidelity. Evaluation of performance was conducted by experts in the fields of MI, T1D, adolescence and/or online education. The second phase (beta) was a quantitative descriptive design conducted in order to evaluate feasibility by examining the acceptability (recruitment, retention and satisfaction) and implementation (diabetes self-management self-efficacy) to determine whether the intervention was appropriate for further testing.
First phase findings showed that the intervention passed all measures with the content experts (n = 6): it was functional, accurate, usable and secure. Improvements to the intervention were made based on reviewer recommendations. For the second phase 5 adolescents between 14 and 17 were enrolled. Three adolescents completed all 4 weeks of the intervention while 2 completed only 3 weeks. Participants (n = 3) rated satisfaction on a 5-point Likert-type scale ranging from “not at all” satisfied (1) to “very much” satisfied (5). There was a positive response to the intervention (M = 4.28, SD = 0.55). Implementation was measured by a pre- and post-test for diabetes self-management self-efficacy. Participants (n = 3) demonstrated overall improvements in diabetes self-management self-efficacy (Z = -2.952, p = .007).
Implications for further Can-Do-Tude research are planned at a metropolitan diabetes center using updated technology including an application platform. Although the sample was small, findings indicate that the intervention can be conducted using a web-based format and there is initial evidence of improvement in self-efficacy for diabetes self-management.
The study used a multi-phase, multi-method approach. The first phase (alpha) of this study was a qualitative descriptive design to examine the intervention’s fidelity. Evaluation of performance was conducted by experts in the fields of MI, T1D, adolescence and/or online education. The second phase (beta) was a quantitative descriptive design conducted in order to evaluate feasibility by examining the acceptability (recruitment, retention and satisfaction) and implementation (diabetes self-management self-efficacy) to determine whether the intervention was appropriate for further testing.
First phase findings showed that the intervention passed all measures with the content experts (n = 6): it was functional, accurate, usable and secure. Improvements to the intervention were made based on reviewer recommendations. For the second phase 5 adolescents between 14 and 17 were enrolled. Three adolescents completed all 4 weeks of the intervention while 2 completed only 3 weeks. Participants (n = 3) rated satisfaction on a 5-point Likert-type scale ranging from “not at all” satisfied (1) to “very much” satisfied (5). There was a positive response to the intervention (M = 4.28, SD = 0.55). Implementation was measured by a pre- and post-test for diabetes self-management self-efficacy. Participants (n = 3) demonstrated overall improvements in diabetes self-management self-efficacy (Z = -2.952, p = .007).
Implications for further Can-Do-Tude research are planned at a metropolitan diabetes center using updated technology including an application platform. Although the sample was small, findings indicate that the intervention can be conducted using a web-based format and there is initial evidence of improvement in self-efficacy for diabetes self-management.
ContributorsPaul, Linda Louise (Author) / Komnenich, Pauline (Thesis advisor) / Spezia Faulkner, Melissa (Committee member) / Shaibi, Gabriel (Committee member) / Arizona State University (Publisher)
Created2017
Description
Background: Effective glucose management using exercise modalities in older patients with type 2 diabetes and activities of daily living (ADL) disabilities are unknown.
Purpose: The study investigated the acute effects of motor-assisted cycling and functional electrical stimulation (FES) cycling on the 2-h postprandial glucose responses compared with sitting control in older adults with type 2 diabetes and ADL disabilities.
Methods: The study used a 3×3 crossover study design. Nine participants were randomly assigned to one of the three treatment sequences: ABC, BCA, and CAB. (A, motor-assisted cycling; B, FES cycling; C, sitting control). Linear mixed models (LMM) with Bonferroni post-hoc tests were used to test the mean differences for the 2-h postprandial glucose, estimated by the area under the curve (AUC) and incremental AUC (iAUC), between intervention and control treatments after adjustment for covariates (e.g., age, sex, and race).
Results: There were significant mean differences for iAUC (p = 0.005) and AUC (p = 0.038) across motor-assisted cycling, control, and FES cycling treatments. The FES cycling had a lower mean of 2-hour postprandial iAUC as compared with sitting control (iAUC 3.98 mmol∙h/L vs 6.92 mmol∙h/L, p = 0.006, effect size [ES] = 1.72) and the motor-assisted cycling (iAUC, 3.98 mmol∙h/L vs 6.19 mmol∙h/L , p = 0.0368, ES = 1.29), respectively. The FES cycling also had a lower mean of the 2-hour postprandial AUC as compared with sitting control (AUC, 18.29 mmol∙h/L vs 20.95 mmol∙h/L, p = 0.043, ES = 0.89), but had an AUC similar to the motor-assisted cycling (18.29 mmol∙h/L vs 20.23 mmol∙h/L , p = 0.183, ES = 0.19). There were no statistical differences in iAUC (6.19 mmol∙h/L vs 6.92 mmol∙h/L) and AUC (20.23 mmol∙h/L vs 20.95 mmol∙h/L) between the motor-assisted cycling and sitting control (all p>0.05).
Conclusion: Performing 30 minutes of FES cycling on a motor-assisted bike (40 Hz, 39 rpm, 25-29 mA) significantly decreased the 2-h postprandial glucose levels in older adults with type 2 diabetes and ADL disabilities. These findings suggested that FES cycling can be a promising exercise modality for glucose management in diabetic patients with ADL disabilities.
Purpose: The study investigated the acute effects of motor-assisted cycling and functional electrical stimulation (FES) cycling on the 2-h postprandial glucose responses compared with sitting control in older adults with type 2 diabetes and ADL disabilities.
Methods: The study used a 3×3 crossover study design. Nine participants were randomly assigned to one of the three treatment sequences: ABC, BCA, and CAB. (A, motor-assisted cycling; B, FES cycling; C, sitting control). Linear mixed models (LMM) with Bonferroni post-hoc tests were used to test the mean differences for the 2-h postprandial glucose, estimated by the area under the curve (AUC) and incremental AUC (iAUC), between intervention and control treatments after adjustment for covariates (e.g., age, sex, and race).
Results: There were significant mean differences for iAUC (p = 0.005) and AUC (p = 0.038) across motor-assisted cycling, control, and FES cycling treatments. The FES cycling had a lower mean of 2-hour postprandial iAUC as compared with sitting control (iAUC 3.98 mmol∙h/L vs 6.92 mmol∙h/L, p = 0.006, effect size [ES] = 1.72) and the motor-assisted cycling (iAUC, 3.98 mmol∙h/L vs 6.19 mmol∙h/L , p = 0.0368, ES = 1.29), respectively. The FES cycling also had a lower mean of the 2-hour postprandial AUC as compared with sitting control (AUC, 18.29 mmol∙h/L vs 20.95 mmol∙h/L, p = 0.043, ES = 0.89), but had an AUC similar to the motor-assisted cycling (18.29 mmol∙h/L vs 20.23 mmol∙h/L , p = 0.183, ES = 0.19). There were no statistical differences in iAUC (6.19 mmol∙h/L vs 6.92 mmol∙h/L) and AUC (20.23 mmol∙h/L vs 20.95 mmol∙h/L) between the motor-assisted cycling and sitting control (all p>0.05).
Conclusion: Performing 30 minutes of FES cycling on a motor-assisted bike (40 Hz, 39 rpm, 25-29 mA) significantly decreased the 2-h postprandial glucose levels in older adults with type 2 diabetes and ADL disabilities. These findings suggested that FES cycling can be a promising exercise modality for glucose management in diabetic patients with ADL disabilities.
Contributorsma, tongyu (Author) / Lee, Chong (Thesis advisor) / Hooker, Steven (Committee member) / Shaibi, Gabriel (Committee member) / Johnston, Carol (Committee member) / Ringenbach, Shannon (Committee member) / Arizona State University (Publisher)
Created2019