Matching Items (121)
Description
As the world energy demand increases, semiconductor devices with high energy conversion efficiency become more and more desirable. The energy conversion consists of two distinct processes, namely energy generation and usage. In this dissertation, novel multi-junction solar cells and light emitting diodes (LEDs) are proposed and studied for high energy conversion efficiency in both processes, respectively. The first half of this dissertation discusses the practically achievable energy conversion efficiency limit of solar cells. Since the demonstration of the Si solar cell in 1954, the performance of solar cells has been improved tremendously and recently reached 41.6% energy conversion efficiency. However, it seems rather challenging to further increase the solar cell efficiency. The state-of-the-art triple junction solar cells are analyzed to help understand the limiting factors. To address these issues, the monolithically integrated II-VI and III-V material system is proposed for solar cell applications. This material system covers the entire solar spectrum with a continuous selection of energy bandgaps and can be grown lattice matched on a GaSb substrate. Moreover, six four-junction solar cells are designed for AM0 and AM1.5D solar spectra based on this material system, and new design rules are proposed. The achievable conversion efficiencies for these designs are calculated using the commercial software package Silvaco with real material parameters. The second half of this dissertation studies the semiconductor luminescence refrigeration, which corresponds to over 100% energy usage efficiency. Although cooling has been realized in rare-earth doped glass by laser pumping, semiconductor based cooling is yet to be realized. In this work, a device structure that monolithically integrates a GaAs hemisphere with an InGaAs/GaAs quantum-well thin slab LED is proposed to realize cooling in semiconductor. The device electrical and optical performance is calculated. The proposed device then is fabricated using nine times photolithography and eight masks. The critical process steps, such as photoresist reflow and dry etch, are simulated to insure successful processing. Optical testing is done with the devices at various laser injection levels and the internal quantum efficiency, external quantum efficiency and extraction efficiency are measured.
ContributorsWu, Songnan (Author) / Zhang, Yong-Hang (Thesis advisor) / Menéndez, Jose (Committee member) / Ponce, Fernando (Committee member) / Belitsky, Andrei (Committee member) / Schroder, Dieter (Committee member) / Arizona State University (Publisher)
Created2010
Description
Background
The purpose of this study is to determine the feasibility of three widely used wearable sensors in research settings for 24 h monitoring of sleep, sedentary, and active behaviors in middle-aged women.
Methods
Participants were 21 inactive, overweight (M Body Mass Index (BMI) = 29.27 ± 7.43) women, 30 to 64 years (M = 45.31 ± 9.67). Women were instructed to wear each sensor on the non-dominant hip (ActiGraph GT3X+), wrist (GENEActiv), or upper arm (BodyMedia SenseWear Mini) for 24 h/day and record daily wake and bed times for one week over the course of three consecutive weeks. Women received feedback about their daily physical activity and sleep behaviors. Feasibility (i.e., acceptability and demand) was measured using surveys, interviews, and wear time.
Results
Women felt the GENEActiv (94.7 %) and SenseWear Mini (90.0 %) were easier to wear and preferred the placement (68.4, 80 % respectively) as compared to the ActiGraph (42.9, 47.6 % respectively). Mean wear time on valid days was similar across sensors (ActiGraph: M = 918.8 ± 115.0 min; GENEActiv: M = 949.3 ± 86.6; SenseWear: M = 928.0 ± 101.8) and well above other studies using wake time only protocols. Informational feedback was the biggest motivator, while appearance, comfort, and inconvenience were the biggest barriers to wearing sensors. Wear time was valid on 93.9 % (ActiGraph), 100 % (GENEActiv), and 95.2 % (SenseWear) of eligible days. 61.9, 95.2, and 71.4 % of participants had seven valid days of data for the ActiGraph, GENEActiv, and SenseWear, respectively.
Conclusion
Twenty-four hour monitoring over seven consecutive days is a feasible approach in middle-aged women. Researchers should consider participant acceptability and demand, in addition to validity and reliability, when choosing a wearable sensor. More research is needed across populations and study designs.
The purpose of this study is to determine the feasibility of three widely used wearable sensors in research settings for 24 h monitoring of sleep, sedentary, and active behaviors in middle-aged women.
Methods
Participants were 21 inactive, overweight (M Body Mass Index (BMI) = 29.27 ± 7.43) women, 30 to 64 years (M = 45.31 ± 9.67). Women were instructed to wear each sensor on the non-dominant hip (ActiGraph GT3X+), wrist (GENEActiv), or upper arm (BodyMedia SenseWear Mini) for 24 h/day and record daily wake and bed times for one week over the course of three consecutive weeks. Women received feedback about their daily physical activity and sleep behaviors. Feasibility (i.e., acceptability and demand) was measured using surveys, interviews, and wear time.
Results
Women felt the GENEActiv (94.7 %) and SenseWear Mini (90.0 %) were easier to wear and preferred the placement (68.4, 80 % respectively) as compared to the ActiGraph (42.9, 47.6 % respectively). Mean wear time on valid days was similar across sensors (ActiGraph: M = 918.8 ± 115.0 min; GENEActiv: M = 949.3 ± 86.6; SenseWear: M = 928.0 ± 101.8) and well above other studies using wake time only protocols. Informational feedback was the biggest motivator, while appearance, comfort, and inconvenience were the biggest barriers to wearing sensors. Wear time was valid on 93.9 % (ActiGraph), 100 % (GENEActiv), and 95.2 % (SenseWear) of eligible days. 61.9, 95.2, and 71.4 % of participants had seven valid days of data for the ActiGraph, GENEActiv, and SenseWear, respectively.
Conclusion
Twenty-four hour monitoring over seven consecutive days is a feasible approach in middle-aged women. Researchers should consider participant acceptability and demand, in addition to validity and reliability, when choosing a wearable sensor. More research is needed across populations and study designs.
ContributorsHuberty, Jennifer (Author) / Ehlers, Diane (Author) / Kurka, Jonathan (Author) / Ainsworth, Barbara (Author) / Buman, Matthew (Author) / College of Health Solutions (Contributor) / School of Nutrition and Health Promotion (Contributor)
Created2015-07-30
Description
This thesis contains three chapters, all of which involve using culturally inclusive education to explore the experiences of religious undergraduate biology students. The first chapter is an essay entitled "Toward Culturally Inclusive Undergraduate Biology Education," which describes a literature review performed with the aim of characterizing the landscape of cultural competence and related terms for biology educators and biology education researchers. This chapter highlights the use of 16 different terms related to cultural competence and presents these terms, their definitions, and highlights their similarities and differences. This chapter also identifies gaps in the cultural competence literature, and presents a set of recommendations to support better culturally inclusive interventions in undergraduate science education. The second chapter, entitled "Different Evolution Acceptance Instruments Lead to Different Research Findings," describes a study in which the source of 30 years of conflicting research on the relationship between evolution acceptance and evolution understanding was determined. The results of this study showed that different instruments used to measure evolution acceptance sometimes lead to different research results and conclusions. The final chapter, entitled "Believing That Evolution is Atheistic is Associated with Poor Evolution Education Outcomes Among Religious College Students," describes a study characterizing definitions of evolution that religious undergraduate biology students may hold, and examines the impact that those definitions of evolution have on multiple outcome variables. In this study, we found that among the most religious students, those who thought evolution is atheistic were less accepting of evolution, less comfortable learning evolution, and perceived greater conflict between their personal religious beliefs and evolution than those who thought evolution is agnostic.
ContributorsDunlop, Hayley Marie (Author) / Brownell, Sara (Thesis director) / Collins, James (Committee member) / Barnes, M. Elizabeth (Committee member) / School of Human Evolution & Social Change (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The number of cancer survivors in the United States is growing rapidly and it is expected to double by 2040. Arizona is nationally ranked with the 14th highest number of survivors, many of which experience a wide range of persisting medical complications that result from the cancer and associated treatment. Consequently, there is an increased need for services tailored to the health and wellness of survivors. Studies have shown that exercise rehabilitation is effective in improving the physical and mental health of this patient population. This project aimed to investigate the status of medically-based exercise rehabilitation for cancer survivors in Arizona. It focused on services offered by cancer treatment centers and cardiac rehabilitation clinics, with cardiac rehabilitation providing a possible delivery method for future cancer exercise rehabilitation. A directory of resources was compiled based on responses to structured telephone interviews with the cancer treatment centers (n=32) and cardiac rehabilitation clinics (n=34) within the state. The directory will serve as a resource for both patients and clinicians by identifying statewide related services that are available at the medical institutions and within the community. Results showed that 42.9% and 39.4% of the cancer treatment centers and cardiac rehabilitation clinics, respectively, offered exercise related services for cancer survivors. 78.6% of cancer centers stated that they refer cancer survivors to physical therapy, while only 35.7% refer survivors to community-based programs. Only 2 cardiac rehabilitation clinics, or 6%, offered preventative cardiology exercise consultations to cancer survivors. In conclusion, rehabilitative exercise resources for cancer survivors in Arizona were limited. Additional cancer rehabilitation efficacy studies are needed to further clarify evidence-based practice guidelines and provide direction for optimal methods of healthcare delivery. It is recommended that this directory remains current with routine updates in an effort to increase patient accessibility to care.
ContributorsHitt, Ellen (Author) / Scales, Robert (Thesis director) / Huberty, Jennifer (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-12
Description
Dielectrophoresis has been shown in the recent past to successfully separate bioparticles of very subtle differences at high resolutions using biophysical forces. In this study, we test the biophysical differences of methicillin resistant and susceptible Staph. aureus that are known to have very similar genomes by using a modified gradient insulator-based dielectrophoresis device (g-iDEP). MRSA is commonly seen in hospitals and is the leading killer of infectious bacteria, claiming the lives of around 10,000 people annually. G-iDEP improves many capabilities within the DEP field including sample size, cost, ease of use and analysis time. This is a promising foundation to creating a more clinically optimized diagnostic tool for both separation and detection of bacteria in the healthcare field. The capture on-set potential for fluorescently tagged MRSA (801 ± 34V) is higher than fluorescently tagged MSSA (610 ± 32V), resulting in a higher electrokinetic to dielectrophoretic mobility ratio for MRSA. Since the strains have proven to be genomically similar through sequencing, it is reasonable to attribute this significant biophysical difference to the added PBP2a enzyme in MRSA. These results are consistent with other bacterial studied within in this device and have proven to be reproducible.
ContributorsSmithers, Jared (Author) / Hayes, Mark (Thesis director) / Woodbury, Neal (Committee member) / School of Criminology and Criminal Justice (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Diabesity is a global epidemic affecting millions worldwide. Diabesity is the term given to the link between obesity and Type II diabetes. It is estimated that ~90% of patients diagnosed with Type II diabetes are overweight or have struggled with excess body fat in the past. Type II diabetes is characterized by insulin resistance which is an impaired response of the body to insulin that leads to high blood glucose levels. Adipose tissue, previously thought of as an inert tissue, is now recognized as a major endocrine organ with an important role in the body's immune response and the development of chronic inflammation. It is speculated that adipose tissue inflammation is a major contributor to insulin resistance particular to Type II diabetes. This literature review explores the popular therapeutic targets and marketed drugs for the treatment of Type II diabetes and their role in decreasing adipose tissue inflammation. rAGE is currently in pre-clinical studies as a possible target to combat adipose tissue inflammation due to its relation to insulin resistance. Metformin and Pioglitazone are two drugs already being marketed that use unique chemical pathways to increase the production of insulin and/or decrease blood glucose levels. Sulfonylureas is one of the first FDA approved drugs used in the treatment of Type II diabetes, however, it has been discredited due to its life-threatening side effects. Bariatric surgery is a form of invasive surgery to rid the body of excess fat and has shown to normalize blood glucose levels. These treatments are all secondary to lifestyle changes, such as diet and exercise which can help halt the progression of Type II diabetes patients.
ContributorsRobles, Alondra Maria (Author) / Woodbury, Neal (Thesis director) / Redding, Kevin (Committee member) / Allen, James (Committee member) / Hendrickson, Kirstin (Committee member) / Sanford School of Social and Family Dynamics (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The first numerical predictions of the dynamical diquark model of multiquark exotic hadrons are presented. Using Born-Oppenheimer potentials calculated from lattice QCD and phenomenological diquark(triquark) masses, mass eigenvalues that are degenerate in spin and isospin are computed from numerical solutions to both coupled and uncoupled Schroedinger equations. Assuming reasonable estimates of the fine-structure splittings, we find that the band structure of our mass spectra agrees well with the experimentally observed spectrum of charmonium-like states. Using our best fits, we predict a number of unobserved states, such as pentaquark states that lie below the charmonium-plus-nucleon threshold.
ContributorsPeterson, Curtis Taylor Taylor (Author) / Lebed, Richard (Thesis director) / Belitsky, Andrei (Committee member) / Department of Physics (Contributor, Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The Heliobacterial Reaction Center (HbRC) is the simplest Type I Reaction Center (RC) known today. However, upon illumination it has been found to produce menaquinol, and this has led to experiments investigating the function of this reduction scheme. The goal of the experiment was to investigate the mechanisms of menaquinol production through the use of Photosystem II (PSII) herbicides that are known to inhibit the QB quinone site in Type II RCs. Seven herbicides were chosen, and out of all of them terbuthylazine showed the greatest effect on the RC in isolated membranes when Transient Absorption Spectroscopy was used. In addition, terbuthylazine decreased menaquinone reduction to menaquinol by ~72%, slightly more than the reported effect of teburtryn (68%)1. In addition, terbuthylazine significantly impacted growth of whole cells under high light more than terbutryn.
ContributorsOdeh, Ahmad Osameh (Author) / Redding, Kevin (Thesis director) / Woodbury, Neal (Committee member) / Allen, James (Committee member) / School of Molecular Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Background:
The positive impacts of yoga on stress, pain, and chronic disease has recently led to the integration of yoga as part of physical therapy (PT) treatment. Due to the lack of training for PTs related to yoga, there is currently a need to provide knowledge and education about how to safely and easily implement therapeutic yoga (TY) as a complementary treatment approach.
Objective:
The purpose of this study was to assess the readiness of PTs (those who do not currently prescribe TY to patients) to integrate TY into treatment, and secondly, the feasibility (i.e., acceptability, demand, and practicality) of a 5-week online TY training to improve the readiness of PT’s to utilize TY in their practice.
Methods:
Licensed Physical Therapist’s (n=103) were recruited nationally through social media and email. Eligible and consented participants were asked to register in a 5-week online TY training course, Readiness for Integrating Yoga Therapeutics into Rehabilitation for PTs (intervention). PTs perceptions of TY and the role of safety and confidence in prescribing TY to patients were measured at baseline and post-intervention using a customized survey. Feasibility outcomes were measured after completion of the 5-week online training course with a survey. Feasibility was measured with acceptability, demand, and practicality. Our benchmarks included: (1) at least 70% of PTs would find the course acceptable, (2) at least 60% would finish the course (i.e., demand) and (3) there would be significant improvements in PTs perceptions of TY.
Results:
A total of 95 licensed PTs registered in the 5-week online TY training course, with 60 PTs (63%) completing the intervention and surveys. Of the PTs who completed the 5-week online training course, most PTs felt they were not ready (n=19/60, 31.7%) or somewhat ready (n=25/60, 41.7%) to integrate TY prior to taking the online training. Over half of PTs thought the online training was acceptable (n= 50/60, 83.3%) and finished the course (n=60/95, 63%). There were significant improvements in personal readiness to prescribe TY, safety prescribing TY, confidence to prescribe TY, current understanding/knowledge of TY and feeling adequately trained and educated to use some form of TY techniques with patients.
Conclusion:
Findings suggest a 5-week online TY training course is feasible in improving PTs readiness to prescribe TY, safety prescribing TY, confidence to prescribe TY, current understanding/knowledge of TY and feeling adequately trained and educated to use some form of TY techniques with patients. Future studies are proposed to test the effectiveness of TY training and education opportunities with PTs to further advance the adoption of TY into PT practice.
The positive impacts of yoga on stress, pain, and chronic disease has recently led to the integration of yoga as part of physical therapy (PT) treatment. Due to the lack of training for PTs related to yoga, there is currently a need to provide knowledge and education about how to safely and easily implement therapeutic yoga (TY) as a complementary treatment approach.
Objective:
The purpose of this study was to assess the readiness of PTs (those who do not currently prescribe TY to patients) to integrate TY into treatment, and secondly, the feasibility (i.e., acceptability, demand, and practicality) of a 5-week online TY training to improve the readiness of PT’s to utilize TY in their practice.
Methods:
Licensed Physical Therapist’s (n=103) were recruited nationally through social media and email. Eligible and consented participants were asked to register in a 5-week online TY training course, Readiness for Integrating Yoga Therapeutics into Rehabilitation for PTs (intervention). PTs perceptions of TY and the role of safety and confidence in prescribing TY to patients were measured at baseline and post-intervention using a customized survey. Feasibility outcomes were measured after completion of the 5-week online training course with a survey. Feasibility was measured with acceptability, demand, and practicality. Our benchmarks included: (1) at least 70% of PTs would find the course acceptable, (2) at least 60% would finish the course (i.e., demand) and (3) there would be significant improvements in PTs perceptions of TY.
Results:
A total of 95 licensed PTs registered in the 5-week online TY training course, with 60 PTs (63%) completing the intervention and surveys. Of the PTs who completed the 5-week online training course, most PTs felt they were not ready (n=19/60, 31.7%) or somewhat ready (n=25/60, 41.7%) to integrate TY prior to taking the online training. Over half of PTs thought the online training was acceptable (n= 50/60, 83.3%) and finished the course (n=60/95, 63%). There were significant improvements in personal readiness to prescribe TY, safety prescribing TY, confidence to prescribe TY, current understanding/knowledge of TY and feeling adequately trained and educated to use some form of TY techniques with patients.
Conclusion:
Findings suggest a 5-week online TY training course is feasible in improving PTs readiness to prescribe TY, safety prescribing TY, confidence to prescribe TY, current understanding/knowledge of TY and feeling adequately trained and educated to use some form of TY techniques with patients. Future studies are proposed to test the effectiveness of TY training and education opportunities with PTs to further advance the adoption of TY into PT practice.
ContributorsThompson, Abigail Ann (Co-author) / Thompson, Abigail (Co-author) / Huberty, Jennifer (Thesis director) / Taylor, Matthew (Committee member) / Ortiz, Alexis (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
In response to a national call within STEM to increase diversity within the sciences, there has been a growth in science education research aimed at increasing participation of underrepresented groups in science, such as women and ethnic/racial minorities. However, an underexplored underrepresented group in science are religious students. Though 82% of the United States population is religiously affiliated, only 52% of scientists are religious (Pew, 2009). Even further, only 32% of biologists are religious, with 25% identifying as Christian (Pew, 2009; Ecklund, 2007). One reason as to why Christian individuals are underrepresented in biology is because faculty may express biases that affect students' ability to persist in the field of biology. In this study, we explored how revealing a Christian student's religious identity on science graduate application would impact faculty's perception of the student during the biology graduate application process. We found that faculty were significantly more likely to perceive the student who revealed their religious identity to be less competent, hirable, likeable, and faculty would be less likely to mentor the student. Our study informs upon possible reasons as to why there is an underrepresentation of Christians in science. This further suggests that bias against Christians must be addressed in order to avoid real-world, negative treatment of Christians in science.
ContributorsTruong, Jasmine Maylee (Author) / Brownell, Sara (Thesis director) / Gaughan, Monica (Committee member) / Barnes, Liz (Committee member) / School of Life Sciences (Contributor) / W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05