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- All Subjects: Educational leadership
- All Subjects: Chemistry
- Genre: Doctoral Dissertation
- Creators: Arizona State University
- Member of: ASU Electronic Theses and Dissertations
Description
Black carbon (BC) is the product of incomplete combustion of biomass and fossil fuels. It is found ubiquitously in nature and is relevant to studies in atmospheric science, soil science, oceanography, and anthropology. Black carbon is best described using a combustion continuum that sub-classifies BC into slightly charred biomass, char, charcoal and soot. These sub-classifications range in particle size, formation temperature, and relative reactivity. Interest in BC has increased because of its role in the long-term storage of organic matter and the biogeochemistry of urban areas. The global BC budget is unbalanced. Production of BC greatly outweighs decomposition of BC. This suggests that there are unknown or underestimated BC removal processes, and it is likely that some of these processes are occurring in soils. However, little is known about BC reactivity in soil and especially in desert soil. This work focuses on soot BC, which is formed at higher temperatures and has a lower relative reactivity than other forms of BC. Here, I assess the contribution of soot BC to central AZ soils and use the isotopic composition of soot BC to identify sources of soot BC. Soot BC is a significant (31%) fraction of the soil organic matter in central AZ and this work suggests that desert and urban soils may be a storage reservoir for soot BC. I further identify previously unknown removal processes of soot BC found naturally in soil and demonstrate that soil soot BC undergoes abiotic (photo-oxidation) and biotic reactions. Not only is soot BC degraded by these processes, but its chemical composition is altered, suggesting that soot BC contains some chemical moieties that are more reactive than others. Because soot BC demonstrates both refractory and reactive character, it is likely that the structure of soot BC; therefore, its interactions in the environment are complex and it is not simply a recalcitrant material.
ContributorsHamilton, George (Author) / Hartnett, Hilairy E (Thesis advisor) / Herckes, Pierre (Committee member) / Hall, Sharon (Committee member) / Arizona State University (Publisher)
Created2013
Description
Recently, a student in a Maricopa County, Arizona area school district drowned during a physical education class, resulting in a heightened awareness of school aquatics safety guidelines. The goal of this study was to use Wenger's idea of nurturing a Community of Practice (CoP) with the existing physical education CoP at GFJRHS (school pseudonym), to examine the current curriculum and enhance the program and safety standards. The study duration was a five-week period; the participants were 7th grade males. This action research addressed the following questions: 1.)To what extent does the new swim curriculum increase students' (a) self-efficacy for swimming, (b) self-efficacy for water safety, (c) perception of swim skills, and (d) perception of water safety skills? 2.) How, and to what extent, do students value different observational learning techniques presented during the swim unit? 3.) To what extent does the new swim curriculum increase students' swimming capabilities? 4.) How does working as a Community of Practice influence implementing an enhanced swim curriculum? 5.) What challenges and improvements do participants report during the enhanced curriculum? A triangulation mixed methods design was used to determine whether observational learning techniques and mini aquatics safety lessons incorporated into the curriculum improved students' swimming ability, self-efficacy, and safety knowledge. Pre-and post-test swim assessments, pre- and post-test surveys, focus group interviews and researcher journal observations provided data for the study. Both quantitative and qualitative data were collected to integrate the strengths of the varied forms of research. Cronbach's coefficient α was computed for the reliability of the survey and a multivariate repeated measures analysis of variance (ANOVA) was conducted to determine whether the new swim curriculum increased students' self-efficacy for swimming, self-efficacy for water safety, perception of swim skills, perception of water safety skills, and swimming capabilities. Results of this study indicated students' self-efficacy and perception of water safety skills increased, students' ability and perception of swimming skills increased, students valued all observational learning techniques, and teachers felt that functioning as a CoP was crucial to the process.
ContributorsJonaitis, Sean (Author) / Wetzel, Keith A (Thesis advisor) / Ewbank, Ann D (Thesis advisor) / Darst, Paul W. (Committee member) / Arizona State University (Publisher)
Created2014
Description
ABSTRACT Education policymakers at the national level have initiated reforms in K-12 education for that past several years that have focused on teacher quality and teacher evaluation. More recently, reforms have included legislation that focuses on administrator quality as well. Included in far-reaching recent legislation in Arizona is a requirement that administrators be evaluated on a standards-based evaluation system that is linked to student outcomes. The end result is an annual summative measure of administrator effectiveness that impacts job retention. Because of this, Arizona administrators have become concerned about rapidly becoming proficient in the new evaluation systems. Administrators rarely have the explicit professional development opportunities they need to collaborate on a shared understanding of these new evaluation systems. This action research study focused on a group of eight administrators in a small urban district grappling with a new, complex, and high-stakes administrator evaluation that is a component of an all-encompassing Teacher Incentive Fund Grant. An existing professional learning time was engaged to assist administrators in lessening their concerns and increasing their understanding and use of the evaluation instrument. Activities were designed to engage the administrators in dynamic, contextualized learning. Participants interacted in a group to interpret the meaning of the evaluation instrument share practical knowledge and support each other's acquisition understanding. Data were gathered with mixed methods. Administrators were given pre-and post-surveys prior to and immediately after this six-week innovation. Formal and informal interviews were conduct throughout the innovation. Additionally, detailed records in the form of meeting records and a researcher journal were kept. Qualitative and quantitative data were triangulated to validate findings. Results identified concerns and understanding of administrators as they attempted to come to a shared understanding of the new evaluation instrument. As a result of learning together, their concerns about the use of the instrument lessened. Other concerns however, remained or increased. Administrators found the process of the Administrator Learning Community valuable and felt their understanding and use of the instrument had increased. Intense concerns about the competing priorities and initiatives led to the administrators to consider a reevaluation of the competing initiatives. Implications from this study can be used to help other administrators and professional development facilitators grappling with common concerns.
ContributorsEsmont, Leah W (Author) / Wetzel, Keith (Thesis advisor) / Ewbank, Ann (Thesis advisor) / McNeil, David (Committee member) / Arizona State University (Publisher)
Created2014
Description
The bleomycins are a family of glycopeptide-derived antibiotics isolated from various Streptomyces species and have been the subject of much attention from the scientific community as a consequence of their antitumor activity. Bleomycin clinically and is an integral part of a number of combination chemotherapy regimens. It has previously been shown that bleomycin has the ability to selectively target tumor cells over their non-malignant counterparts. Pyrimidoblamic acid, the N-terminal metal ion binding domain of bleomycin is known to be the moiety that is responsible for O2 activation and the subsequent chemistry leading to DNA strand scission and overall antitumor activity. Chapter 1 describes bleomycin and related DNA targeting antitumor agents as well as the specific structural domains of bleomycin. Various structural analogues of pyrimidoblamic acid were synthesized and subsequently incorporated into their corresponding full deglycoBLM A6 derivatives by utilizing a solid support. Their activity was measured using a pSP64 DNA plasmid relaxation assay and is summarized in Chapter 2. The specifics of bleomycin—DNA interaction and kinetics were studied via surface plasmon resonance and are presented in Chapter 3. By utilizing carefully selected 64-nucleotide DNA hairpins with variable 16-mer regions whose sequences showed strong binding in past selection studies, a kinetic profile was obtained for several BLMs for the first time since bleomycin was discovered in 1966. The disaccharide moiety of bleomycin has been previously shown to be a specific tumor cell targeting element comprised of L-gulose-D-mannose, especially between MCF-7 (breast cancer cells) and MCF-10A ("normal" breast cells). This phenomenon was further investigated via fluorescence microscopy using multiple cancerous cell lines with matched "normal" counterparts and is fully described in Chapter 4.
ContributorsBozeman, Trevor C (Author) / Hecht, Sidney M. (Thesis advisor) / Chaput, John (Committee member) / Gould, Ian (Committee member) / Arizona State University (Publisher)
Created2013
Description
Thiol functionalization is one potentially useful way to tailor physical and chemical properties of graphene oxides (GOs) and reduced graphene oxides (RGOs). Despite the ubiquitous presence of thiol functional groups in diverse chemical systems, efficient thiol functionalization has been challenging for GOs and RGOs, or for carbonaceous materials in general. In this work, thionation of GOs has been achieved in high yield through two new methods that also allow concomitant chemical reduction/thermal reduction of GOs; a solid-gas metathetical reaction method with boron sulfides (BxSy) gases and a solvothermal reaction method employing phosphorus decasulfide (P4S10). The thionation products, called "mercapto reduced graphene oxides (m-RGOs)", were characterized by employing X-ray photoelectron spectroscopy, powder X-ray diffraction, UV-Vis spectroscopy, FT-IR spectroscopy, Raman spectroscopy, electron probe analysis, scanning electron microscopy, (scanning) transmission electron microscopy, nano secondary ion mass spectrometry, Ellman assay and atomic force microscopy. The excellent dispersibility of m-RGOs in various solvents including alcohols has allowed fabrication of thin films of m-RGOs. Deposition of m-RGOs on gold substrates was achieved through solution deposition and the m-RGOs were homogeneously distributed on gold surface shown by atomic force microscopy. Langmuir-Blodgett (LB) films of m-RGOs were obtained by transferring their Langmuir films, formed by simple drop casting of m-RGOs dispersion on water surface, onto various substrates including gold, glass and indium tin oxide. The m-RGO LB films showed low sheet resistances down to about 500 kΩ/sq at 92% optical transparency. The successful results make m-RGOs promising for applications in transparent conductive coatings, biosensing, etc.
ContributorsJeon, Kiwan (Author) / Seo, Dong-Kyun (Thesis advisor) / Jones, Anne K (Committee member) / Yarger, Jeffery (Committee member) / Arizona State University (Publisher)
Created2013
Description
DNA is a unique, highly programmable and addressable biomolecule. Due to its reliable and predictable base recognition behavior, uniform structural properties, and extraordinary stability, DNA molecules are desirable substrates for biological computation and nanotechnology. The field of DNA computation has gained considerable attention due to the possibility of exploiting the massive parallelism that is inherent in natural systems to solve computational problems. This dissertation focuses on building novel types of computational DNA systems based on both DNA reaction networks and DNA nanotechnology. A series of related research projects are presented here. First, a novel, three-input majority logic gate based on DNA strand displacement reactions was constructed. Here, the three inputs in the majority gate have equal priority, and the output will be true if any two of the inputs are true. We subsequently designed and realized a complex, 5-input majority logic gate. By controlling two of the five inputs, the complex gate is capable of realizing every combination of OR and AND gates of the other 3 inputs. Next, we constructed a half adder, which is a basic arithmetic unit, from DNA strand operated XOR and AND gates. The aim of these two projects was to develop novel types of DNA logic gates to enrich the DNA computation toolbox, and to examine plausible ways to implement large scale DNA logic circuits. The third project utilized a two dimensional DNA origami frame shaped structure with a hollow interior where DNA hybridization seeds were selectively positioned to control the assembly of small DNA tile building blocks. The small DNA tiles were directed to fill the hollow interior of the DNA origami frame, guided through sticky end interactions at prescribed positions. This research shed light on the fundamental behavior of DNA based self-assembling systems, and provided the information necessary to build programmed nanodisplays based on the self-assembly of DNA.
ContributorsLi, Wei (Author) / Yan, Hao (Thesis advisor) / Liu, Yan (Thesis advisor) / Chen, Julian (Committee member) / Gould, Ian (Committee member) / Arizona State University (Publisher)
Created2014
Description
This thesis describes the fabrication of several new classes of Ge1-x-ySixSny materials with the required compositions and crystal quality to engineer the band gaps above and below that of elemental Ge (0.8 eV) in the near IR. The work initially focused on Ge1-x-ySixSny (1-5% Sn, 4-20% Si) materials grown on Ge(100) via gas-source epitaxy of Ge4H10, Si4H10 and SnD4. Both intrinsic and doped layers were produced with defect-free microstructure and viable thickness, allowing the fabrication of high-performance photodetectors. These exhibited low ideality factors, state-of-the-art dark current densities and adjustable absorption edges between 0.87 and 1.03 eV, indicating that the band gaps span a significant range above that of Ge. Next Sn-rich Ge1-x-ySixSny alloys (2-4% Si and 4-10% Sn) were fabricated directly on Si and were found to show significant optical emission using photoluminescence measurements, indicating that the alloys have direct band gaps below that of pure Ge in the range of 0.7-0.55 eV. A series of Sn-rich Ge1-x-ySixSny analogues (y>x) with fixed 3-4% Si content and progressively increasing Sn content in the 4-10% range were then grown on Ge buffered Si platforms for the purpose of improving the material's crystal quality. The films in this case exhibited lower defect densities than those grown on Si, allowing a meaningful study of both the direct and indirect gaps. The results show that the separation of the direct and indirect edges can be made smaller than in Ge even for non-negligible 3-4% Si content, confirming that with a suitable choice of Sn compositions the ternary Ge1-x-ySixSny reproduces all features of the electronic structure of binary Ge1-ySny, including the sought-after indirect-to-direct gap cross over. The above synthesis of optical quality Ge1-x-ySixSny on virtual Ge was made possible by the development of high quality Ge-on-Si buffers via chemical vapor deposition of Ge4H10. The resultant films exhibited structural and electrical properties significantly improved relative to state-of-the-art results obtained using conventional approaches. It was found that pure Ge4H10 facilitates the control of residual doping and enables p-i-n devices whose dark currents are not entirely determined by defects and whose zero-bias collection efficiencies are higher than those obtained from samples fabricated using alternative Ge-on-Si approaches.
ContributorsXu, Chi (Author) / Kouvetakis, John (Thesis advisor) / Menéndez, Jose (Thesis advisor) / Chizmeshya, Andrew (Committee member) / Drucker, Jeffrey (Committee member) / Ponce, Fernando (Committee member) / Arizona State University (Publisher)
Created2013
Description
The purpose of the study is to explore the identity development and organizational culture of a student organization, the National Association of Latino Fraternal Organizations council (NALFO) by implementing a community of practice approach at a large, public university in southwestern United States. The objective is to construct a sustainable camaraderie among the existing Latino fraternal organizations at the university to influence leadership development, work toward a common vision, and a cohesive and systematic approach to collaboration, consequently transforming organizational culture. This study investigates the factors that contribute to and/or inhibit increased communication and collaboration and to describe the experiences of Latino fraternal members who are purposefully engaged in a community of practice. There are 57 fraternal organizations in five umbrella councils at the university, including predominately Caucasian, historically African American, Latino, and Multicultural groups, whose platforms are commonly leadership, scholarship, and philanthropy. This action research examines the experiences of six NALFO members individually and working as a community with the guidance of a mentor (the researcher). The researcher employs use of an anonymous initial and post electronic survey, a participant personal statement, an intentional and purposeful community of practice, a semi-structured individual interview, and focus groups to collect data. Findings suggest that length of membership and fraternal experience influence participant responses; however, the themes remain consistent. Building relationships, perception (by members and outsiders), identity development, organizational management, and challenging perspectives (from outside influences) are factors that influence the organizational culture of the organization. On the post electronic survey all participants indicate that the implementation of an intentional community of practice can benefit the organization by encouraging participation and increasing communication. While participants suggest activities for encouraging member engagement, they determine that actual participation would be dependent on individual motivation.
ContributorsHeredia, Anna-Maria (Author) / Rund, James (Thesis advisor) / Calleroz White, Mistalene (Thesis advisor) / Corey, Frederick (Committee member) / Arizona State University (Publisher)
Created2013
Description
Peer learning is one of the longest established and most intensively researched forms of learning. As a form of peer learning, peer tutoring is characterized by specific role-taking as tutor or tutee with high focus on curriculum content. In the late 18th century, Andrew Bell undoubtedly became the first person in the world to use peer tutoring in a systematic fashion within a school setting. Due to its miraculous success, Bell affirmed that peer tutoring was the new method of practical education and was essential to every academic institution. Early in American education, teachers relied on certain students to teach others (i.e., peer tutoring) but this occurred on an informal, impromptu, as needed basis. This type of peer tutoring lasted well into the 20th century. A recent change in the traditional face of peer tutoring arrangements for U.S. schools has occurred due to more than 30 years of research at four major tutoring centers. Peer tutoring has moved away from an informal and casual approach to a more formal and robust method of teaching and learning. However, at the researcher's high school, peer tutoring was still very casual, informal, and practically non-existent. Consequently, the researcher created a peer tutoring club, and developed, and implemented a peer tutoring program. The researcher conducted a mixed-methods study with design-based research (DBR) as the preferred research design in order to discover what constitutes an ideal peer tutor and an ideal peer tutoring session. The researcher utilized qualitative means to analyze the following data: 1) field notes, 2) impromptu interviews, 3) questionnaires, 4) focus group interviews, and 5) a semi-structured interview. The researcher utilized quantitative means to analyze the following data: 1) sessions tutored survey and 2) archival data (e.g., daily attendance, school records). Analysis of qualitative and quantitative data suggested that the ideal peer tutor was qualified (e.g., desire, character traits, content mastery), trained (e.g., responsibilities, methodologies, procedures), and experienced. Likewise, in addition to having an ideal peer tutor, an ideal peer tutoring session took place in an environment conducive to learning and tutees were prepared and actively participated.
ContributorsJohnson, Brian (Author) / Carlson, David (Thesis advisor) / Barnard, Wendy (Committee member) / Moore, David (Committee member) / Arizona State University (Publisher)
Created2014
Description
Rapid and reliable separation and analysis of proteins require powerful analytical methods. The analysis of proteins becomes especially challenging when only small sample volumes are available, concomitantly with low concentrations of proteins. Time critical situations pose additional challenges. Due to these challenges, conventional macro-scale separation techniques reach their limitations. While microfluidic devices require only pL-nL sample volumes, they offer several advantages such as speed, efficiency, and high throughput. This work elucidates the capability to manipulate proteins in a rapid and reliable manner with a novel migration technique, namely dielectrophoresis (DEP). Since protein analysis can often be achieved through a combination of orthogonal techniques, adding DEP as a gradient technique to the portfolio of protein manipulation methods can extend and improve combinatorial approaches. To this aim, microfluidic devices tailored with integrated insulating obstacles were fabricated to create inhomogeneous electric fields evoking insulator-based DEP (iDEP). A main focus of this work was the development of pre-concentration devices where topological micropost arrays are fabricated using standard photo- and soft lithographic techniques. With these devices, positive DEP-driven streaming of proteins was demonstrated for the first time using immunoglobulin G (IgG) and bovine serum albumin. Experimentally observed iDEP concentrations of both proteins were in excellent agreement with positive DEP concentration profiles obtained by numerical simulations. Moreover, the micropost iDEP devices were improved by introducing nano-constrictions with focused ion beam milling with which numerical simulations suggested enhancement of the DEP effect, leading to a 12-fold increase in concentration of IgG. Additionally, concentration of β-galactosidase was observed, which seems to occur due to an interplay of negative DEP, electroosmosis, electrokinesis, diffusion, and ion concentration polarization. A detailed study was performed to investigate factors influencing protein DEP under DC conditions, including electroosmosis, electrophoresis, and Joule heating. Specifically, temperature rise within the iDEP device due to Joule heating was measured experimentally with spatial and temporal resolution by employing the thermosensitive dye Rhodamine B. Unlike DNA and cells, protein DEP behavior is not well understood to date. Therefore, this detailed study of protein DEP provides novel information to eventually optimize this protein migration method for pre-concentration, separation, and fractionation.
ContributorsNakano, Asuka (Author) / Ros, Alexandra (Thesis advisor) / Hayes, Mark (Committee member) / Levitus, Marcia (Committee member) / Arizona State University (Publisher)
Created2014