Matching Items (18)
Filtering by
- All Subjects: Chemistry
- Creators: School of Molecular Sciences
- Resource Type: Text
Description
The free-base tetra-tolyl-porphyrin and the corresponding cobalt and iron porphyrin complexes were synthesized and characterized to show that this class of compound can be promising, tunable catalysts for carbon dioxide reduction. During cyclic voltammetry experiments, the iron porphyrin showed an on-set of ‘catalytic current’ at an earlier potential than the cobalt porphyrin’s in organic solutions gassed with carbon dioxide. The cobalt porphyrin yielded larger catalytic currents, but at the same potential as the electrode. This difference, along with the significant changes in the porphyrin’s electronic, optical and redox properties, showed that its capabilities for carbon dioxide reduction can be controlled by metal ions, allotting it unique opportunities for applications in solar fuels catalysis and photochemical reactions.
ContributorsSkibo, Edward Kim (Author) / Moore, Gary (Thesis director) / Woodbury, Neal (Committee member) / School of Molecular Sciences (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Joseph Rotblat (1908-2005) was the only physicist to leave the Manhattan Project for moral reasons before its completion. He would spend the rest of his life advocating for nuclear disarmament. His activities for disarmament resulted in the formation, in 1957, of the Pugwash conferences, which emerged as the leading global forum to advance limits on nuclear weapons during the Cold War. Rotblat's efforts, and the activities of Pugwash, resulted in both being awarded the Nobel Peace Prize in 1995. Rotblat is a central figure in the global history of resistance to the spread of nuclear weapons. He also was an important figure in the emergence, after World War II, of a counter-movement to introduce new social justifications for scientific research and new models for ethics and professionalism among scientists. Rotblat embodies the power of the individual scientist to say "no" and thus, at least individually, put limits of conscience on his or her scientific activity. This paper explores the political and ethical choices scientists make as part of their effort to behave responsibly and to influence the outcomes of their work. By analyzing three phases of Rotblat's life, I demonstrate how he pursued his ideal of beneficial science, or science that appears to benefit humanity. The three phases are: (1) his decision to leave the Manhattan Project in 1944, (2) his role in the creation of Pugwash in 1957 and his role in the rise of the organization into international prominence and (3) his winning the Nobel Peace Prize in 1995. These three phases of Rotblat's life provide a singular window of the history of nuclear weapons and the international movement for scientific responsibility in the 50 years since the bombing of Hiroshima in 1945. While this paper does not provide a complete picture of Rotblat's life and times, I argue that his experiences shed important light on the difficult question of the individual responsibility of scientists.
ContributorsEvans, Alison Dawn (Author) / Zachary, Gregg (Thesis director) / Hurlbut, Ben (Committee member) / Francis, Sybil (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2015-05
Description
Iron (Fe) scarcity limits biological productivity in high-nutrient low-chlorophyll (HNLC) ocean regions. Thus, the input, output and abundance of Fe in seawater likely played a critical role in shaping the development of modern marine ecosystems and perhaps even contributed to past changes in Earth’s climate. Three sources of Fe—wind-blown dust, hydrothermal activity, and sediment dissolution—carry distinct Fe isotopic fingerprints, and can therefore be used to track Fe source variability through time. However, establishing the timing of this source variability through Earth’s history remains challenging because the major depocenters for dissolved Fe in the ocean lack well-established chronologies. This is due to the fact that they are difficult to date with traditional techniques such as biostratigraphy and radiometric dating. Here, I develop age models for sediments collected from the International Drilling Program Expedition 329 by measuring the Os (osmium) isotopic composition of the hydrogenous portion of the clays. These extractions enable dating of the clays by aligning the Os isotope patterns observed in the clays to those in a reference curve with absolute age constraints through the Cenozoic. Our preliminary data enable future development of chronologies for three sediment cores from the high-latitude South Pacific and Southern Oceans, and demonstrate a wider utility of this method to establish age constraints on pelagic sediments worldwide. Moreover, the preliminary Os isotopic data provides a critical first step needed to examine the changes in Fe (iron) sources and cycling on millions of years timescales. Fe isotopic analysis was conducted at the same sites in the South Pacific and demonstrates that there are significant changes in the sources of Fe to the Southern Ocean over the last 90 Ma. These results lay the groundwork for the exploration of basin-scale sources to Fe source changes, which will have implications for understanding how biological productivity relates to Fe source variability over geological timescales.
ContributorsTegler, Logan Ashley (Author) / Anbar, Ariel (Thesis director) / Herckes, Pierre (Committee member) / Romaniello, Stephen (Committee member) / Department of English (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This thesis aims to address the ethics of keeping the big cats, such as lions, tigers, and leopards, in zoos. It is a practice that has generated some controversy in light of scientific studies reporting stress among wide-ranging animals in captive enclosures, as well as in the context of wider discussions in animal welfare and conservation ethics in zoos. A driving question for this project, therefore, was "What are the arguments for and against keeping large felids in zoos/captivity?" This thesis examines the historical and current ethical approaches to evaluating the ethics of maintaining big cats in zoos. Due to many of the big cat species listed as endangered species on the IUCN redlist, the species-centered approach to zoo ethics is becoming the common viewpoint, and, as a result, zoos are deemed ethical because of their contribution to ex situ conservation practices. Further, the ethical arguments against zoos are minimized when the zoos provide suitable and appropriate enclosures for their large felids. Of course, not all zoos are created equal; the ethics of zoos need to be evaluated on a case-by-case basis, but in general, it is ethical to maintain big cats in zoos.
ContributorsZeien, Krista Marie (Author) / Minteer, Ben (Thesis director) / Smith, Andrew (Committee member) / Ellison, Karin (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Sickle Cell Disease (SCD) is a prevalent genetic disease in Africa, and specifically in Kenya. The lack of available relevant disease education and screening mean that most don't understand the importance of getting testing and many children die before they can get prophylactic care. This project was designed to address the lack of knowledge with supplemental educational materials to be partnered with an engineering capstone project that provides a low cost diagnostic test.
ContributorsShawver, Jamie Christine (Author) / Caplan, Michael (Thesis director) / Snyder, Jan (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Characterization of a Lipid Coating on the Surface of Silk Produced by the Embiid Antipaluria urichi
Description
Insects of the order Embiidina spin sheets of very thin silk fibers from their forelimbs to build silken shelters on bark and in leaf litter in tropical climates. Their shelters are very stiff and hydrophobic to keep out predators and rain. In this study, the existence of an outer lipid coating on silk produced by the embiid Antipaluria urichi is shown using scanning and transmission electron microscopy, FT-IR, and water drop contact angle analysis. Subsequently, the composition of the lipid layer is then characterized by 1H NMR and GC-MS.
ContributorsOsborn Popp, Thomas Michael (Author) / Yarger, Jeffery (Thesis director) / Holland, Gregory (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor)
Created2014-05
Description
The prospect of anti-aging or life extension technology is controversial in biogerentology but deemed even by skeptical experts to warrant discussion. I discuss the justifications that the probability of life extension technology being developed in the near future is reasonably high and that this research justifies the time and money it receives. I investigate potential ethical and societal issues anti-aging technology might create. This paper addresses inequality of access, economic cost, changes in quality of life, the role of death in human life, if and how the technology should be regulated and how parties who choose not to undergo treatment can be fairly treated, even when they are a minority.
ContributorsGlesener, Julia Hannah (Author) / McGregor, Joan (Thesis director) / DeSerpa, Allan (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2015-05
Description
For many pre-health and graduate programs, organic chemistry is often the most difficult prerequisite course that students will take. To alleviate this difficulty, an intelligent tutoring system was developed to provide valuable feedback to practice problems within organic chemistry. This paper focuses on the design and use of an intelligent input parser for nomenclature questions within this system. Students in Dr. Gould's Fall 2014 organic chemistry class used this system and their data was collected to analyze the effectiveness of the input parser. Overall the students' feedback was optimistic and there was a positive relationship between test scores and student use of the system.
ContributorsHusarcik, Edward Andrew (Author) / Gould, Ian (Thesis director) / VanLehn, Kurt (Committee member) / Beerman, Eric (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor)
Created2015-05
Description
As a child passes through the birth canal, they become inoculated with vital gram positive and gram-negative bacteria, aerobes and anaerobes. Breast milk helps to support this growing microbiome by providing oligosaccharides that support its proliferation. Breast milk can be considered the most nutritious source of food available to a growing infant by providing the necessary nutrients, growth hormones and antibodies to promote digestive health, growth, and a strong immune system. The Developmental Origins of Health and Disease Theory (DOHaD) is a theory that suggests a growing fetus and nursing child's nutrients and immune system are dependent on the mother's exposure to nutrients and toxins. Studies have shown a positive correlation between the length of nursing and a child's overall health through life. In addition, consuming an enriched diet after weaning builds a strong immunological and nutritional basis from which the child can grow. This leads to improvements in a child's overall health, which has beneficial long-term effects on morbidity and mortality. This project applied the theory to two Middle Horizon (AD500-1100) individuals from Akapana, Tiwanaku, in the Lake Titicaca Basin, Bolivia. Stable nitrogen and carbon isotope analysis was applied to first molar serial samples of these two individuals to determine weaning age and early childhood diet. Both individuals were male; one male died in adolescence between the age of 9-15 years, and the other died as an elderly adult around the age of 50-59 years. The results showed that the male who died in adulthood was provisioned with supplemental and post-weaning foods high in animal protein, and received breast milk until around 37 months of age. The adolescent male was weaned between 11-12 months and consumed a diet dominated by C4 plants \u2014 most likely maize \u2014 with much less protein. The correlation between prolonged access to breast milk and a healthier and more nutritious childhood diet and longevity are consistent with the theory discussed above.
ContributorsCampbell, Sibella Sweelin (Author) / Knudson, Kelly (Thesis director) / Marsteller, Sara (Committee member) / Greenwald, Alexandra (Committee member) / School of Human Evolution & Social Change (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
This study seeks to determine whether female and male students in general chemistry courses differ in exam and course-based performance. Using data from previous semesters of CHM 101 (Marks), CHM 101 (Bauer), CHM 114 (Seo, Windman), CHM 113/116 (Cabirac), and CHM 117/118 (Williams) courses taught at Arizona State University, the total exam scores and final course grades for each student were recorded and analyzed. The results of this study differ greatly by course type, as each course corresponded to a different STEM major. While CHM 113/116, the pre-medicinal majors course, saw evidence of stereotype threat via lower female exam performance, the other courses saw no statistical difference between male and female performance on their exam scores or overall course grades. For CHM 101, this was understandable, as the majority of students were nursing majors, who likely did not experience tokenism or feel stereotyped negatively in their science classes. However, CHM 114, the engineering majors course, and CHM 117/118, the research science course, saw parity with respect to male and female student performance. This suggests the possibility that female students face adversity in science and math courses before college that cause only those with high self-efficacy to advance to a career in these fields.
ContributorsWoner, Victoria Elaine (Author) / Gould, Ian (Thesis director) / Saenz, Delia (Committee member) / Austin, Ara (Committee member) / Department of Psychology (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12