Digital Commons @ Harrisburg University of Science and Technology
Not a member yet
435 research outputs found
Sort by
The Male Adult Working-Class Student In Formal Higher Education: An Identity Crisis?
No full textThe purpose of this study was to explore how working-class adult students maintain their aspects of their identity in a formal higher education environment. While the literature has highlighted social class issues in adult education little is known about why and how some working-class students maintain aspects of their identity while some students choose to abandon their working-class roots and attempt to assimilate into the dominant, middle-and upper-class culture of formal education. This study explored the following questions: What does being working-class mean to working-class students? What are the experiences of working-class students attending formal higher education? How do working-class students maintain aspects of their identity? This study used a qualitative methodology and heuristic inquiry. This was accomplished by conducting a series of in-depth interviews with current and former adult working-class students. The purpose of these interviews was to elicit open-ended responses that enabled understanding and captured the points of view of these students. The participants’ perceptions and experiences resulted in an understanding of their worldview and exploration of their social class awareness. The research findings centered on three areas – working-class identity and meaning, experiences in higher education, and responsibilities of higher education and the working-class student. The participants identified characteristics of working-class identity; how they have maintained this identity; the roles, responsibilities and meaning of work; and dynamics of the intersection of social class. Findings regarding experiences in higher education included influencers and motivators to attend higher education; challenges of the working-class student; and attitudes, attributes, and motivations while engaged in higher education. The thesis provided an analysis related to social class identity and findings on how working-class students maintain aspects of their identity while adopting aspects of middle-class identity as well as how critical consciousness is developed. Other areas expanded upon were the challenges of the working-class student, specifically feelings of impostership, lack of cultural capital, and cultural suicide. Finally, the study explored how students of working-class origin coexist in the working- and middle-classes with a focus on opportunities versus threats and the role of the working-class student as an intellectual laborer and organic intellectual
Desulfovibrio desulfuricans G20 Tetraheme Cytochrome Structure at 1.5 A˚ and Cytochrome Interaction with Metal Complexes
Get PDFThe structure of the type I tetraheme cytochrome c3 from Desulfovibrio desulfuricans G20 was determined to 1.5 A˚ by X-ray crystallography. In addition to the oxidized form, the structure of the molybdate-bound form of the protein was determined from oxidized crystals soaked in sodium molybdate. Only small structural shifts were obtained with metal binding, consistent with the remarkable structural stability of this protein. In vitro experiments with pure cytochrome showed that molybdate could oxidize the reduced cytochrome, although not as rapidly as U(VI) present as uranyl acetate. Alterations in the overall conformation and thermostability of the metal-oxidized protein were investigated by circular dichroism studies. Again, only small changes in protein structure were documented. The location of the molybdate ion near heme IV in the crystal structure suggested heme IV as the site of electron exit from the reduced cytochrome and implicated Lys14 and Lys56 in binding. Analysis of structurally conserved water molecules in type I cytochrome c3 crystal structures identified interactions predicted to be important for protein stability and possibly for intramolecular electron transfer among heme molecule
Studies on the formation of DNA-cationic lipid composite films and DNA hybridization in the composites
Get PDFThe formation of composite films of double-stranded DNA and cationic lipid molecules (octadecylamine, ODA) and the hybridization of complementary single-stranded DNA molecules in such composite films are demonstrated. The immobilization of DNA is accomplished by simple immersion of a thermally evaporated ODA film in the DNA solution at close to physiological pH. The entrapment of the DNA molecules in the cationic lipid film is dominated by attractive electrostatic interaction between the negatively charged phosphate backbone of the DNA molecules and the protonated amine molecules in the thermally evaporated film and has been quantified using quartz crystal microgravimetry (QCM). Fluorescence studies of DNA-ODA composite films obtained by sequential immersion of the ODA matrix in the complementary single-stranded DNA solutions using ethidium bromide intercalator clearly showed that the hybridization of the DNA single strands had occurred within the composite film. Furthermore, fluorescence studies of the preformed double-stranded DNA-ODA biocomposite film indicated DNA entrapment without distortion to the native double-helical structure. The DNA-ODA biocomposite films have been further characterized with Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements. The DNA-fatty lipid composite films would serve as model systems for understanding DNA-membrane interactions as well as in the study of DNA-drug/protein interactions. This approach also shows promise for the synthesis of patterned DNA films and consequent application in disease detection and genome sequencing
Cationic surfactant mediated hybridization and hydrophobization of DNA molecules at the liquid/liquid interface and their phase transfer
Get PDFHybridization of complementary oligonucleotides mediated by a cationic surfactant at the water/hexane interface leads to hydrophobic, double-helical DNA which may be readily phase transferred to the organic phase and cast into thin films on solid substrates
Linear superclusters of colloidal gold particles by electrostatic assembly on DNA templates
No full textThe electrostatic assembly of positively charged colloidal gold nanoparticles on the negatively charged phosphate backbone of DNA molecules was demonstrated. The gold nanoparticles yielded linear superstructures using DNA templates. The use of DNA templates with different geometries in electrostatic self-assembly of colloidal nanoparticles and semiconductor quantum dots was investigated
Hybridization of DNA by sequential immobilization of oligonucleotides at the air-water interface
Get PDFThe hybridization of DNA by sequential electrostatic and hydrogen-bonding immobilization of single-stranded complementary oligonucleotides at the air-water interface with cationic Langmuir monolayers is demonstrated. The complexation of the single-stranded DNA molecules with octadecylamine (ODA) Langmuir monolayers was followed in time by monitoring the pressure-area isotherms. A large (and slow) expansion of the ODA monolayer was observed during each stage of complexation in the following sequence: primary single-stranded DNA followed by complementary single-stranded DNA followed by the intercalator, ethidium bromide. Langmuir-Blodgett (LB) films of the ODA-DNA complex were formed on different substrates and characterized using quartz-crystal microgravimetry (QCM), Fourier transform infrared spectroscopy (FTIR), polarized-UV-vis and fluorescence spectroscopy, as well as thermal melting studies. These measurements clearly showed that hybridization of the complementary single-stranded DNA molecules had occurred at the air-water interface, leading to the characteristic double-helical structure. Furthermore, it was observed that the DNA molecules in the LB films were oriented parallel to the substrate withdrawal direction