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- Genre: Masters Thesis
- Creators: Arizona State University
- Creators: Chakraborty, Bijeta
- Member of: ASU Electronic Theses and Dissertations
Description
Type 2 diabetes affects approximately 7.3% of Americans, leading to debilitating and life-threatening comorbidities. Estrogen and testosterone levels have been linked to inflammatory and oxidative stress markers, as well as glucose and insulin concentrations. The present study was designed to determine the link between sex differences, glucose control, and inflammation and oxidative stress related to daily almond ingestion among subjects with type 2 diabetes. Subjects were randomized to an intervention group, which received 1.5 oz. almonds daily for 12 weeks, or to the matched control group, which maintained their current diet. No significant differences were found in changes in glucose control in response to ingestion of almonds. However, CRP was significantly reduced by an average of 36.2% in those that received almonds daily (p = 0.017). Although not significant, women randomized to the intervention group appeared to have improvements in insulin resistance compared to women with no dietary change. Results suggest that the addition of almonds to the diet may be an effective intervention for managing inflammation associated with type 2 diabetes. The addition of almonds to the diet is a low cost intervention that is easily implemented into daily lifestyle. Due to the small sample size, additional studies are needed to determine the impact and mechanisms of almond ingestion in subjects with type 2 diabetes.
ContributorsPetersen, Katherine Nicole (Author) / Karen, Sweazea (Thesis advisor) / Carol, Johnston (Committee member) / Christy, Lespron (Committee member) / Arizona State University (Publisher)
Created2014
Description
Efficiency of components is an ever increasing area of importance to portable applications, where a finite battery means finite operating time. Higher efficiency devices need to be designed that don't compromise on the performance that the consumer has come to expect. Class D amplifiers deliver on the goal of increased efficiency, but at the cost of distortion. Class AB amplifiers have low efficiency, but high linearity. By modulating the supply voltage of a Class AB amplifier to make a Class H amplifier, the efficiency can increase while still maintaining the Class AB level of linearity. A 92dB Power Supply Rejection Ratio (PSRR) Class AB amplifier and a Class H amplifier were designed in a 0.24um process for portable audio applications. Using a multiphase buck converter increased the efficiency of the Class H amplifier while still maintaining a fast response time to respond to audio frequencies. The Class H amplifier had an efficiency above the Class AB amplifier by 5-7% from 5-30mW of output power without affecting the total harmonic distortion (THD) at the design specifications. The Class H amplifier design met all design specifications and showed performance comparable to the designed Class AB amplifier across 1kHz-20kHz and 0.01mW-30mW. The Class H design was able to output 30mW into 16Ohms without any increase in THD. This design shows that Class H amplifiers merit more research into their potential for increasing efficiency of audio amplifiers and that even simple designs can give significant increases in efficiency without compromising linearity.
ContributorsPeterson, Cory (Author) / Bakkaloglu, Bertan (Thesis advisor) / Barnaby, Hugh (Committee member) / Kiaei, Sayfe (Committee member) / Arizona State University (Publisher)
Created2013
Description
ABSTRACT Epidemiological studies have suggested a link between nut consumption and weight. The possible effects of regular nut consumption as a method of weight loss has shown minimal results with 2-3 servings of nut products per day. This 8 week study sought to investigate the effect of more modest nut consumption (1 oz./day, 5 days/week) on dietary compensation in healthy overweight individuals. Overweight and obese participants (n = 28) were recruited from the local community and were randomly assigned to either almond (NUT) or control (CON) group in this randomized, parallel-arm study. Subjects were instructed to eat their respective foods 30 minutes before the dinner meal. 24 hour diet recalls were completed pre-trial and at study weeks 1, 4 and 8. Self-reported satiety data were completed at study weeks 1, 4, and 8. Attrition was unexpectedly high, with 13 participants completing 24 dietary recall data through study week 8. High attrition limited statistical analyses. Results suggested a lack of effect for time or interaction for satiety data (within groups p = 0.997, between groups p = 0.367). Homogeneity of of inter-correlations could not be tested for 24-hour recall data as there were fewer than 2 nonsingular cell covariance matrices. In conclusion, this study was unable to prove or disprove the effectiveness of almonds to induce dietary compensation.
ContributorsJahns, Marshall (Author) / Johnston, Carol (Thesis advisor) / Hall, Richard (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Arizona State University (Publisher)
Created2011
Description
Nut consumption, specifically almonds, have been shown to help maintain weight and influence disease risk factors in adult populations. Limited studies have been conducted examining the effect of a small dose of almonds on energy intake and body weight. The objective of this study was to determine the influence of pre-meal almond consumption on energy intake and weight in overweight and obese adults. In this study included 21, overweight or obese, participants who were considered healthy or had a controlled disease state. This 8-week parallel arm study, participants were randomized to consume an isocaloric amount of almonds, (1 oz) serving, or two (2 oz) cheese stick serving, 30 minutes before the dinner meal, 5 times per week. Anthropometric measurements including weight, waist circumference, and body fat percentage were recorded at baseline, week 1, 4, and 8. Measurement of energy intake was self-reported for two consecutive days at week 1, 4 and 8 using the ASA24 automated dietary program. The energy intake after 8 weeks of almond consumption was not significantly different when compared to the control group (p=0.965). In addition, body weight was not significantly reduced after 8 weeks of the almond intervention (p=0.562). Other parameters measured in this 8-week trial did not differ between the intervention and the control group. These data presented are underpowered and therefore inconclusive on the effects that 1 oz of almonds, in the diet, 5 per week has on energy intake and bodyweight.
ContributorsMcBride, Lindsey (Author) / Johnston, Carol (Thesis advisor) / Swan, Pamela (Committee member) / Mayol-Kreiser, Sandra (Committee member) / Arizona State University (Publisher)
Created2011
Description
Class D Amplifiers are widely used in portable systems such as mobile phones to achieve high efficiency. The demands of portable electronics for low power consumption to extend battery life and reduce heat dissipation mandate efficient, high-performance audio amplifiers. The high efficiency of Class D amplifiers (CDAs) makes them particularly attractive for portable applications. The Digital class D amplifier is an interesting solution to increase the efficiency of embedded systems. However, this solution is not good enough in terms of PWM stage linearity and power supply rejection. An efficient control is needed to correct the error sources in order to get a high fidelity sound quality in the whole audio range of frequencies. A fundamental analysis on various error sources due to non idealities in the power stage have been discussed here with key focus on Power supply perturbations driving the Power stage of a Class D Audio Amplifier. Two types of closed loop Digital Class D architecture for PSRR improvement have been proposed and modeled. Double sided uniform sampling modulation has been used. One of the architecture uses feedback around the power stage and the second architecture uses feedback into digital domain. Simulation & experimental results confirm that the closed loop PSRR & PS-IMD improve by around 30-40 dB and 25 dB respectively.
ContributorsChakraborty, Bijeta (Author) / Bakkaloglu, Bertan (Thesis advisor) / Garrity, Douglas (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2012
Description
In this thesis, a digital input class D audio amplifier system which has the ability
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
ContributorsBai, Jing (Author) / Bakkaloglu, Bertan (Thesis advisor) / Arizona State University (Publisher)
Created2015
Description
ABSTRACT
Objective: The purpose of this randomized parallel two-arm trial was to examine the effect that an intervention of combining daily almond consumption (2.5 ounces) with a walking program would have on heart rate recovery and resting heart rate when compared to the control group that consumed a placebo (cookie butter) in men and postmenopausal women, aged 20-69, in Phoenix, Arizona.
Design: 12 men and women from Phoenix, Arizona completed an 8-week walking study (step goal: 10,000 steps per day). Subjects were healthy yet sedentary, non-smokers, free from gluten or nut allergies, who had controlled blood pressure. At week 5, participants were randomized into one of two groups: ALM (2.5 oz of almonds daily for last 3 weeks of trial) or CON (4 tbsp of cookie butter daily for last 3 weeks of trial). Body weight, BMI, and percent body fat were measured using a stadiometer and Tanita at the screening visit. Resting heart rate, heart rate recovery, and anthropometric measurements were taken at weeks 0, 5, and 8.
Results: 8 weeks of walking 10,000 steps per day, with or without 3 weeks of almond consumption did not significantly improve heart rate recovery (p=0.818) or resting heart rate (0.968).
Conclusions: Almond consumption in combination with a walking intervention does not significantly improve heart rate recovery or resting heart rate.
Objective: The purpose of this randomized parallel two-arm trial was to examine the effect that an intervention of combining daily almond consumption (2.5 ounces) with a walking program would have on heart rate recovery and resting heart rate when compared to the control group that consumed a placebo (cookie butter) in men and postmenopausal women, aged 20-69, in Phoenix, Arizona.
Design: 12 men and women from Phoenix, Arizona completed an 8-week walking study (step goal: 10,000 steps per day). Subjects were healthy yet sedentary, non-smokers, free from gluten or nut allergies, who had controlled blood pressure. At week 5, participants were randomized into one of two groups: ALM (2.5 oz of almonds daily for last 3 weeks of trial) or CON (4 tbsp of cookie butter daily for last 3 weeks of trial). Body weight, BMI, and percent body fat were measured using a stadiometer and Tanita at the screening visit. Resting heart rate, heart rate recovery, and anthropometric measurements were taken at weeks 0, 5, and 8.
Results: 8 weeks of walking 10,000 steps per day, with or without 3 weeks of almond consumption did not significantly improve heart rate recovery (p=0.818) or resting heart rate (0.968).
Conclusions: Almond consumption in combination with a walking intervention does not significantly improve heart rate recovery or resting heart rate.
ContributorsMcElaney, Elizabeth Anne (Author) / Johnston, Carol S (Thesis advisor) / Lespron, Christy L (Committee member) / Sweazea, Karen L (Committee member) / Arizona State University (Publisher)
Created2016