Matching Items (208)
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Mutations in the DNA of somatic cells, resulting from inaccuracies in DNA<br/>replication or exposure to harsh conditions (ionizing radiation, carcinogens), may be<br/>loss-of-function mutations, and the compounding of these mutations can lead to cancer.<br/>Such mutations can come in the form of thymine dimers, N-đť›˝ glycosyl bond hydrolysis,<br/>oxidation by hydrogen peroxide or

Mutations in the DNA of somatic cells, resulting from inaccuracies in DNA<br/>replication or exposure to harsh conditions (ionizing radiation, carcinogens), may be<br/>loss-of-function mutations, and the compounding of these mutations can lead to cancer.<br/>Such mutations can come in the form of thymine dimers, N-đť›˝ glycosyl bond hydrolysis,<br/>oxidation by hydrogen peroxide or other radicals, and deamination of cytosine to uracil.<br/>However, many cells possess the machinery to counteract the deleterious effects of<br/>such mutations. While eukaryotic DNA repair enzymes decrease the incidence of<br/>mutations from 1 mistake per 10^7 nucleotides to 1 mistake per 10^9 nucleotides, these<br/>mutations, however sparse, are problematic. Of particular interest is a mutation in which<br/>uracil is incorporated into DNA, either by spontaneous deamination of cysteine or<br/>misincorporation. Such mutations occur about one in every 107 cytidine residues in 24<br/>hours. DNA uracil glycosylase (UDG) recognizes these mutations and cleaves the<br/>glycosidic bond, creating an abasic site. However, the rate of this form of DNA repair<br/>varies, depending on the nucleotides that surround the uracil. Most enzyme-DNA<br/>interactions depend on the sequence of DNA (which may change the duplex twist),<br/>even if they only bind to the sugar-phosphate backbone. In the mechanism of uracil<br/>excision, UDG flips the uracil out of the DNA double helix, and this step may be<br/>impaired by base pairs that neighbor the uracil. The deformability of certain regions of<br/>DNA may facilitate this step in the mechanism, causing these regions to be less<br/>mutable. In DNA, base stacking, a form of van der Waals forces between the aromatic<br/>nucleic bases, may make these uracil inclusions more difficult to excise. These regions,<br/>stabilized by base stacking interactions, may be less susceptible to repair by<br/>glycosylases such as UDG, and thus, more prone to mutation.

ContributorsUgaz, Bryan T (Author) / Levitus, Marcia (Thesis director) / Van Horn, Wade (Committee member) / Department of Physics (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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The COVID-19 pandemic has resulted in preventative measures and has led to extensive changes in lifestyle for the vast majority of the American population. As the pandemic progresses, a growing amount of evidence shows that minority groups, such as the Deaf community, are often disproportionately and uniquely affected. Deaf

The COVID-19 pandemic has resulted in preventative measures and has led to extensive changes in lifestyle for the vast majority of the American population. As the pandemic progresses, a growing amount of evidence shows that minority groups, such as the Deaf community, are often disproportionately and uniquely affected. Deaf people are directly affected in their ability to personally socialize and continue with daily routines. More specifically, this can constitute their ability to meet new people, connect with friends/family, and to perform in their work or learning environment. It also may result in further mental health changes and an increased reliance on technology. The impact of COVID-19 on the Deaf community in clinical settings must also be considered. This includes changes in policies for in-person interpreters and a rise in telehealth. Often, these effects can be representative of the pre-existing low health literacy, frequency of miscommunication, poor treatment, and the inconvenience felt by Deaf people when trying to access healthcare. Ultimately, these effects on the Deaf community must be taken into account when attempting to create a full picture of the societal shift caused by COVID-19.

ContributorsAsuncion, David Leonard Esquiera (Co-author) / Dubey, Shreya (Co-author) / Patterson, Lindsey (Thesis director) / Lee, Lindsay (Committee member) / Harrington Bioengineering Program (Contributor) / Department of Physics (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Stardust grains can provide useful information about the Solar System environment before the Sun was born. Stardust grains show distinct isotopic compositions that indicate their origins, like the atmospheres of red giant stars, asymptotic giant branch stars, and supernovae (e.g., Bose et al. 2010). It has been argued that some

Stardust grains can provide useful information about the Solar System environment before the Sun was born. Stardust grains show distinct isotopic compositions that indicate their origins, like the atmospheres of red giant stars, asymptotic giant branch stars, and supernovae (e.g., Bose et al. 2010). It has been argued that some stardust grains likely condensed in classical nova outbursts (e.g., Amari et al. 2001). These nova candidate grains contain 13C, 15N and 17O-rich nuclides which are produced by proton burning. However, these nuclides alone cannot constrain the stellar source of nova candidate grains. Nova ejecta is rich in 7Be that decays to 7Li (which has a half-life of ~53 days). I want to measure 6,7Li isotopes in nova candidate grains using the NanoSIMS 50L (nanoscale secondary ion mass spectrometry) to establish their nova origins without ambiguity. Several stardust grains that are nova candidate grains were identified in meteorite Acfer 094 on the basis of their oxygen isotopes. The identified silicate and oxide stardust grains are <500 nm in size and exist in the meteorite surrounded by meteoritic silicates. Therefore, 6,7Li isotopic measurements on these grains are hindered because of the large 300-500 nm oxygen ion beam in the NanoSIMS. I devised a methodology to isolate stardust grains by performing Focused Ion Beam milling with the FIB – Nova 200 NanoLab (FEI) instrument. We proved that the current FIB instrument cannot be used to prepare stardust grains smaller than 1 𝜇m due to lacking capabilities of the FIB. For future analyses, we could either use the same milling technique with the new and improved FIB – Helios 5 UX or use the recently constructed duoplasmatron on the NanoSIMS that can achieve a size of ~75 nm oxygen ion beam.

ContributorsDuncan, Ethan Jay (Author) / Bose, Miatrayee (Thesis director) / Starrfield, Sumner (Committee member) / Desch, Steve (Committee member) / School of Earth and Space Exploration (Contributor) / Department of Physics (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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This research endeavor explores the 1964 reasoning of Irish physicist John Bell and how it pertains to the provoking Einstein-Podolsky-Rosen Paradox. It is necessary to establish the machinations of formalisms ranging from conservation laws to quantum mechanical principles. The notion that locality is unable to be reconciled with the quantum

This research endeavor explores the 1964 reasoning of Irish physicist John Bell and how it pertains to the provoking Einstein-Podolsky-Rosen Paradox. It is necessary to establish the machinations of formalisms ranging from conservation laws to quantum mechanical principles. The notion that locality is unable to be reconciled with the quantum paradigm is upheld through analysis and the subsequent Aspect experiments in the years 1980-1982. No matter the complexity, any local hidden variable theory is incompatible with the formulation of standard quantum mechanics. A number of strikingly ambiguous and abstract concepts are addressed in this pursuit to deduce quantum's validity, including separability and reality. `Elements of reality' characteristic of unique spaces are defined using basis terminology and logic from EPR. The discussion draws directly from Bell's succinct 1964 Physics 1 paper as well as numerous other useful sources. The fundamental principle and insight gleaned is that quantum physics is indeed nonlocal; the door into its metaphysical and philosophical implications has long since been opened. Yet the nexus of information pertaining to Bell's inequality and EPR logic does nothing but assert the impeccable success of quantum physics' ability to describe nature.

ContributorsRapp, Sean R (Author) / Foy, Joseph (Thesis director) / Martin, Thomas (Committee member) / School of Earth and Space Exploration (Contributor) / Department of Physics (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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The use of enzyme-catalyst interfaces is underexplored in the field of biocatalysis, particularly in studies on enabling novel reactivity of enzymes. For this thesis, the HaloTag® protein tagging platform was proposed as a bioconjugation method for a pinacol coupling reaction using lipases, as a model for novel reactivities proceeding via

The use of enzyme-catalyst interfaces is underexplored in the field of biocatalysis, particularly in studies on enabling novel reactivity of enzymes. For this thesis, the HaloTag® protein tagging platform was proposed as a bioconjugation method for a pinacol coupling reaction using lipases, as a model for novel reactivities proceeding via ketyl radical intermediates and hydrogen-bonding-facilitated redox attenuation. After an initial lipase screening of 9 lipases, one lipase (Candida rugosa) was found to perform the pinacol coupling of p-anisaldehyde under standard conditions (fluorescein and 530nm light, 3% yield). Based on a retrosynthetic analysis for the photocatalyst-incorporated HaloTag® linker, the intermediates haloamine 1 and aldehyde 6 were synthesized. Further experiments are underway or planned to complete linker synthesis and conduct pinacol coupling experiments with a bioconjugated system. This project underscores the promising biocatalytic promiscuity of lipases for performing reactions proceeding through ketyl radical intermediates, as well as the underdeveloped potential of incorporating bioengineering principles like bioconjugation into biocatalysis to overcome kinetic barriers to electron transfer and optimize biocatalytic reactions.

ContributorsMcrae, Kenna Christine (Author) / Biegasiewicz, Kyle (Thesis director) / Ghirlanda, Giovanna (Committee member) / Moore, Ana (Committee member) / Department of Physics (Contributor) / School of Human Evolution & Social Change (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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The colossal global counterfeit market and advances in cryptography including quantum computing supremacy have led the drive for a class of anti-counterfeit tags that are physically unclonable. Dendrites, previously considered an undesirable side effect of battery operation, have promise as an extremely versatile version of such tags, with their fundamental

The colossal global counterfeit market and advances in cryptography including quantum computing supremacy have led the drive for a class of anti-counterfeit tags that are physically unclonable. Dendrites, previously considered an undesirable side effect of battery operation, have promise as an extremely versatile version of such tags, with their fundamental nature ensuring that no two dendrites are alike and that they can be read at multiple magnification scales. In this work, we first pursue a simulation for electrochemical dendrites that elucidates fundamental information about their growth mechanism. We then translate these results into physical dendrites and demonstrate methods of producing a hash from these dendrites that is damage-tolerant for real-world verification. Finally, we explore theoretical curiosities that arise from the fractal nature of dendrites. We find that uniquely ramified dendrites, which rely on lower ion mobility and conductive deposition, are particularly amenable to wavelet hashing, and demonstrate that these dendrites have strong commercial potential for securing supply chains at the highest level while maintaining a low price point.

ContributorsSneh, Tal (Author) / Kozicki, Michael (Thesis director) / Gonzalez-Velo, Yago (Committee member) / School of Molecular Sciences (Contributor) / Department of Physics (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Treatment log files for spot scanning proton therapy provide a record of delivery accuracy, but they also contain diagnostic information for machine performance. A collection of patient log files can identify machine performance trends over time. This facilitates the identification of machine issues before they cause downtime or degrade treatment

Treatment log files for spot scanning proton therapy provide a record of delivery accuracy, but they also contain diagnostic information for machine performance. A collection of patient log files can identify machine performance trends over time. This facilitates the identification of machine issues before they cause downtime or degrade treatment quality. At Mayo Clinic Arizona, all patient treatment logs are stored in a database. These log files contain information including the gantry, beam position, monitor units (MUs), and gantry angle. This data was analyzed to identify trends, which were then correlated with quality assurance measurements and maintenance records.

ContributorsGrayson, Madison Emily (Author) / Alarcon, Ricardo (Thesis director) / Robertson, Daniel (Committee member) / Department of Physics (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Externalizing behaviors are pervasive, widespread, and disruptive across a multitude of settings and developmental contexts. While the conventional diathesis-stress model typically measures the disordered end of the spectrum, studies that span the range of behavior, from externalizing to competence behaviors, are necessary to see the full picture. To that end,

Externalizing behaviors are pervasive, widespread, and disruptive across a multitude of settings and developmental contexts. While the conventional diathesis-stress model typically measures the disordered end of the spectrum, studies that span the range of behavior, from externalizing to competence behaviors, are necessary to see the full picture. To that end, this study examined the additive and nonadditive relations of a dimension of parenting (ranging from warm to rejecting), and variants in dopamine, vasopressin, and neuropeptide-y receptor genes on externalizing/competence in a large sample of predominantly Caucasian twin children in toddlerhood, middle childhood, and early adolescence. Variants within each gene were hypothesized to increase biological susceptibility to both negative and positive environments. Consistent with prediction, warmth related to lower externalizing/higher competence at all ages. Earlier levels of externalizing/competence washed out the effect of parental warmth on future externalizing/competence with the exception of father warmth in toddlerhood marginally predicting change in externalizing/competence from toddlerhood to middle childhood. Warmth was a significant moderator of the heritability of behavior in middle childhood and early adolescence such that behavior was less heritable (mother report) and more heritable (father report) in low warmth environments. Interactions with warmth and the dopamine and vasopressin genes in middle childhood and early adolescence emphasize the moderational role gene variants play in relations between the rearing environment and child behavior. For dopamine, the long variant related to increased sensitivity to parent warmth such that the children displayed more externalizing behaviors when exposed to rejection but they also displayed more competence behaviors when exposed to high warmth. Vasopressin moderation was only present under conditions of parental warmth, not rejection. Interactions with neuropeptide-y and warmth were not significant. The picture that emerges is one of gene-environment interplay, wherein the influence of both parenting and child genotype each depend on the level of the other. As genetic research moves forward, gene variants previously implicated as conferring risk for disorder should be reexamined in conjunction with salient aspects of the environment on the full range of the behavioral outcome of interest.
ContributorsO'Brien, T. Caitlin (Author) / Lemery-Chalfant, Kathryn (Thesis advisor) / Eisenberg, Nancy (Committee member) / Enders, Craig (Committee member) / Nagoshi, Craig (Committee member) / Arizona State University (Publisher)
Created2011
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The purpose of this study was to examine the longitudinal relations of maternal behaviors, children`s temperamental negative emotionality, and children`s emotion perception processes, including emotion perception accuracy (EPA) and emotion perception bias (EPB), to children`s conduct disorder symptoms in a normative sample. Separate structural equation models were conducted to assess

The purpose of this study was to examine the longitudinal relations of maternal behaviors, children`s temperamental negative emotionality, and children`s emotion perception processes, including emotion perception accuracy (EPA) and emotion perception bias (EPB), to children`s conduct disorder symptoms in a normative sample. Separate structural equation models were conducted to assess whether parenting or children`s proneness to negative emotions at 24-30 (T2), 36-42 (T3) and 48-54 (T4) months predicted children`s EPA and EPB over time, and whether T3 and T4 children`s emotion perception processes were predictive of children`s conduct disorder at 72 months of age (T5). None of the hypothesized longitudinal relations was supported; however, other noteworthy results were observed. T3 children`s proneness to negative emotions was positively related to children`s concurrent bias toward anger. The latent constructs of negative parenting, children`s proneness to negative emotions, and the observed measure of children`s emotion perception accuracy showed stability over time, whereas the observed measures of children`s bias toward understanding distinct negative emotions were unrelated across time. In addition, children`s expressive language was predicted by children`s earlier emotion perception accuracy, which emphasized the importance of improving children`s emotion understanding skills during early years. Furthermore, the previously established negative relation between EPA and EPB variables was only partially supported. Findings regarding the relations between parenting, children`s negative emotionality and emotion perception processes are discussed from a developmental perspective.
ContributorsSeyed Nozadi, Sara (Author) / Spinrad, Tracy L. (Thesis advisor) / Eisenberg, Nancy (Committee member) / Bradley, Robert (Committee member) / Eggum, Natalie (Committee member) / Arizona State University (Publisher)
Created2011
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This dissertation examines Japanese preschool teachers' cultural practices and beliefs about the pedagogy of social-emotional development. The study is an interview-based, ethnographic study, which is based on the video-cued mutivocal ethnographic method. This study focuses on the emic terms that Japanese preschool teachers use to explain their practices, such as

This dissertation examines Japanese preschool teachers' cultural practices and beliefs about the pedagogy of social-emotional development. The study is an interview-based, ethnographic study, which is based on the video-cued mutivocal ethnographic method. This study focuses on the emic terms that Japanese preschool teachers use to explain their practices, such as amae (dependency), omoiyari (empathy), sabishii (loneliness), mimamoru (watching and waiting) and garari (peripheral participation). My analysis suggests that sabishii, amae, and omoiyari form a triad of emotional exchange that has a particular cultural patterning and salience in Japan and in the Japanese approach to the socialization of emotions in early childhood. Japanese teachers think about the development of the class as a community, which is different from individual-centric Western pedagogical perspective that gives more attention to each child's development. Mimamoru is a pedagogical philosophy and practice in Japanese early childhood education. A key component of Japanese teachers' cultural practices and beliefs about the pedagogy of social-emotional development is that the process requires the development not only of children as individuals, but also of children in a preschool class as a community. In addition, the study suggests that at a deeper level these emic concepts reflect more general Japanese cultural notions of time, space, sight, and body. This dissertation concludes with the argument that teachers' implicit cultural practices and beliefs is "A cultural art of teaching." Teachers' implicit cultural practices and beliefs are harmonized in the teachers' mind and body, making connections between them, and used depending on the nuances of a situation, as informed by teachers' conscious and unconscious thoughts. The study has also shown evidence of similar practices and logic vertically distributed within Japanese early childhood education, from the way teachers act with children, to the way directors act with teachers, to the way government ministries act with directors, to the way deaf and hearing educators act with their deaf and hearing students. Because these practices are forms of bodily habitus and implicit Japanese culture, it makes sense that they are found across fields of action.
ContributorsHayashi, Akiko (Author) / Tobin, Joseph (Thesis advisor) / Eisenberg, Nancy (Committee member) / Nakagawa, Kathryn (Committee member) / Fischman, Gustavo (Committee member) / Swadener, Elizabeth (Committee member) / Arizona State University (Publisher)
Created2011