4,828 research outputs found
A Case Report of Case Report Pursuit by Medical Student
Medical students often seek case reports as vehicles for academic writing opportunities, conference presentation avenues, and residency/fellowship application highlights. Here we review a case where, due to unfortunate circumstances, a student made a unique diagnosis central to proper patient clinical care, wished to write up the case subsequently, but was ultimately excluded from the final work stemming from the patient case. We review the pitfalls that occurred in the process of pursuing publication of an interesting case, the educational value of pursuing case reports for students, the necessity for strong mentorship in this process, and general principles that medical students can follow regarding case report creation to avoid being burned
Processing, Structure, and Properties of Amorphous Aluminum Alloys
Although research has been conducted on amorphous aluminum-based alloys, most of the research has focused on melt-spun ribbons. There has been significantly less research on mechanically alloyed amorphous powder even though mechanically alloyed powder seems to have more potential for the production of bulk amorphous aluminumbased alloys. In addition, there has not been adequate research conducted on the local atomic structure of amorphous aluminum alloys, and a greater understanding of the relationship between processing, structure, and properties is necessary.
In the following thesis, multiple investigations have been performed to understand the structure, processing, and properties of aluminum-based amorphous alloys. These studies sought to develop a methodology for the production of amorphous aluminum alloys by mechanical alloying, understand how composition affects the glassforming ability, understand the crystallization and its effects on structure and properties, and consolidate the mechanically alloyed powder and examine the resultant structure and properties.
High-energy ball milling was used to synthesize aluminum-based alloys containing amorphous and nanocrystalline phases to investigate the compositional effects of transition metals (TM) on the amorphization and crystallization processes of the ballmilled Al85Y7Fe5TM3 alloys (TM = Ni, Co, Cu, and Fe) were investigated.
The local atomic structure of mechanically alloyed Al85Y7Fe8 and Al83Y7Fe8Ti2 were examined by high-energy synchrotron x-ray diffraction. Diffraction results showed that Al85Y7Fe8structure to be nanocrystalline, while Al83Y7Fe8Ti2is amorphous. The pair distribution function analyses revealed that local structure of Al85Y7Fe8was dominated by Al, Fe, and Al3Y short range ordered regions. On the other hand, the local structure of Al83Y7Fe8Ti2was comprised of Al, Al6Fe, and Al3Y short-range order regions, in which the order extended for about 8 angstroms.
Efforts to consolidate the mechanically alloyed amorphous powder were made by quasi-isostatic forging at different temperatures. Samples were also processed containing different levels of coarse grain crystalline aluminum to evaluate the production of bimodal composites.
In addition to the research performed on amorphous aluminum alloys, research on the mechanical behavior of the local atomic structure of a bulk metallic glass was performed. The internal strain was measured for a Zr57Nb5Cu15.4Ni12.6Al10 BMG in-situ by neutron diffraction
Late Prehistoric Lithic Economies in the Prairie Peninsula: a Comparison of Oneota and Langford in Southern Wisconsin and Northern Illinois
This thesis is an examination of the environmental settlement patterns and the organization of lithic technology surrounding Upper Mississippian groups in Southeastern Wisconsin and Northern Illinois. The sites investigated in this study are the Washington Irving (11K52) and Koshkonong Creek Village (47JE379) habitation sites, contemporaneous creekside Langford and Oneota sites located approximately 90 kilometers apart. A two-kilometer catchment of Washington Irving is compared to that of the Koshkonong Creek Village to clarify the nature of environmental variation in Langford and Oneota settlement patterns and increase our understanding of Upper Mississippian horticulturalist lifeways. Lithic tool and mass debitage analyses use an assemblage-based approach to understand the lithic economies at each site, accounting for procurement and manufacturing strategies and assemblage diversity and complexity
Applicability of an Autodeposited Organic Coating as a Primer for Agricultural Tractor Hitch Assemblies to Improve Corrosion Resistance
Use of the CID W22 as a South African English speech discrimination test
South Africa currently lacks a pre-recorded South African English (SAE) specific speech discrimination test. In the absence of such a test, the SAE speaker recording (Tygerberg recording) of the American (USA) English (AE) CID W22 wordlists--in combination with the original American CID W22 normative data--is the most widely used alternative. The reliability and validity of this method, however, has never been formally assessed. This study assessed the performance of 15 normal hearing, female, first language SAE speakers on the first two full-lists of Tygerberg CID W22 recording at 20, 30, 40, 50, 60 and 70 dBSPL, and compared their scores to the American CID W22 wordlist normative data. Overall, the South African subjects performed worse than the original American normative data at the lower presentation intensities ( 40 dBSPL), however, was considered a viable option. These results reiterate the need for large scale, South African specific normative studies for the CID W22 wordlists if they are to continue their role as the dominant speech discrimination wordlists in South Africa
Mitochondria as a Potential Antifungal Target for Isocyanide Compounds
The discovery of antibiotics and antifungals greatly impacted medicine and human health, allowing the effective treatment of infections that were previously deadly. However, due to routine and sometimes excessive usage of these compounds, the development of antimicrobial resistance has created a need for new antibiotic and antifungal compounds. Isocyanide compounds have been shown to have antibacterial, antifungal, and anti-cancer properties, but very little is known about their biochemical effects. Our research aims to understand the mechanism of action of isocyanide compounds. We have conducted a genetic screen of a Saccharomyces gene-deletion (“knockout”) collection on media containing an easily synthesized model isocyanide compound, para-nitrophenyl isocyanide (p-NPIC). This allowed us to identify genes which, when deleted, render the mutant strains resistant or hypersensitive to the compound. Based on our genetic screen for hypersensitive mutants, we hypothesize that the isocyanides impact mitochondrial function, specifically altering the function of the Cu++-containing respiratory complex, Cytochrome C Oxidase (Complex IV). Our findings provide new information on the mechanism(s) of action of this class of antimicrobials and will help guide the development of new molecules based on lead-compounds such as p-NPIC
Advanced Stirling Convertor (ASC) Technology Maturation
The Advanced Stirling Convertor (ASC) development effort was initiated by NASA Glenn Research Center (GRC) with contractor Sunpower Inc. to develop high efficiency thermal-to-electric power conversion technology for NASA Radioisotope Power Systems. Early successful performance demonstrations led to the expansion of the project as well as adoption of the technology by the Department of Energy (DOE) and system integration contractor Lockheed Martin Space Systems Company as part of the Advanced Stirling Radioisotope Generator (ASRG) flight project. The ASRG integrates a pair of ASCs to convert the heat from a pair of General Purpose Heat Source (GPHS) modules into electrical power. The expanded NASA ASC effort included development of several generations of ASC prototypes or Engineering Units to help prepare the ASC technology and Sunpower for flight implementation. Sunpower later had two parallel contracts allowing the last of the NASA Engineering Units called ASC-E3 to serve as pathfinders for the ASC-F flight convertors being built for DOE. The ASC-E3 convertors utilized the ASC-F flight specifications and were built using the ASC-F design and process documentation. Shortly after the first ASC-F Pair achieved initial operation, due to budget constraints, the DOE ASRG flight development contract was terminated. NASA continues to invest in the development of Stirling RPS technology including continued production of the ASC-E3 convertors, seven of which have been delivered with one additional unit in production. Starting in FY2015, Stirling Convertor Technology Maturation has been reorganized as an element of the RPS Stirling Cycle Technology Development (SCTD) Project and long-term plans for continued Stirling technology advancement are in reformulation. This paper provides a status on the ASC project, an overview of advancements made in the design and production of the ASC at Sunpower, and a summary of acceptance tests, reliability tests, and tactical tests at NASA GRC that demonstrate the capabilities of the ASC
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