John Wesley - man of one book : An investigatin of the centrality of the Bible in the life and works of John Wesley with special emphasis on his labours as an interpreter of the New Testament

Arnett, William M Drew Univ. 1954 국내박사

The quinic acid gene cluster in Neurospora: Sequence comparison and gene expression

Arnett, Diana R Kent State University 2005 해외박사(DDOD)

The quinic acid (qa) cluster of Neurospora crassa is subject to two levels of control. The primary mechanism is dependent on the presence of the inducer, quinic acid: in the absence of inducer, the genes are expressed at low basal levels. The cluster is also subject to catabolite repression---the genes are repressed in the presence of a preferred carbon source, such as dextrose, even in the presence of inducer. To focus on this second level of control, I utilized a constitutive mutant of the qa gene cluster which contains a deletion of the qa-1S repressor gene. This deletion removes the primary control mechanism, ensuring that any observed effect is due to catabolite repression. Northern blot analysis indicates that transcription of the qa-y gene, which encodes a quinate permease, is repressed by the presence of dextrose even in the absence of the qa-1S repressor, demonstrating that catabolite repression of the qa cluster may be occurring by inducer exclusion. Transcription of the remainder of the qa genes does not appear to be repressed to a significant degree in the constitutive mutant by the presence of dextrose. Additionally, I used 2-dimensional protein gel electrophoresis to examine the expression of the qa proteins in samples grown under different growth conditions. Preliminary results show changes in protein expression in repressor mutants when compared to wild-type. Gene regulation mechanisms can be revealed by comparing homologous sequences in related species. I sequenced the permease and repressor genes, along with the associated regulatory regions in the homothallic Neurospora species N. africana and N. terricola. The coding regions of both species share a high degree of homology to N. crassa: the permease genes are 93% identical and the repressor 91--92% identical. The noncoding region upstream of the repressor is less conserved, with N. africana showing 41% identity and N. terricola 59% identity to N. crassa. In contrast, the region upstream of the permease gene is highly conserved, with both species 83% identical to N. crassa. This highly conserved region could contain binding sites needed to affect catabolite repression of the permease gene.

Densification and mechanical properties of nanocrystalline FeAl

Arnett, Michael D University of Illinois at Urbana-Champaign 1999 해외박사(DDOD)

The densification and mechanical properties of nanocrystalline FeAl was studied using sinterforging and impression creep measurements. Powders of nanocrystalline FeAl were prepared by mechanical alloying mixtures of Fe and Al powders; the as-milled powder was a disordered solid-solution of Al and Fe with a BCC lattice structure. Sinterforging was performed on partially dense compacts produced from this powder. An unexpected decrease in total deformation was observed when the temperature was raised from 500°C to 525°C. This is attributed to a combination of grain growth and reordering of the lattice to the equilibrium B2 structure. The apparent stress exponent deduced from the results of step-load tests was 5.5, which is indicative of deformation by a dislocation mechanism. Bulging of the specimen during the sinterforging tests prevented calculation of the density in-situ; the bulging is attributed to dead zones resulting from friction at the specimen/platen interface. Full densification of FeAl was achieved while retaining a grain size far below 100 nm. Impression creep measurements were performed on nanocrystalline FeAl specimens sinterforged to full density. The tests were conducted over the temperature range of 500–600°C, and using punches with diameters of 0.5 and 0.2 mm. For specimens sinterforged at 500°C, a decrease in creep rate was observed between 500°C and 525°C, similar to the decrease in deformation rate observed in sinterforging experiments. The stress exponent was calculated from the steady-state impression velocities at punching stresses of 400, 600 and 800 MPa, which are equivalent to conventional stresses of 130, 195 and 260MPa. The stress exponent was 2 at all temperatures; its value is attributed to a deformation mechanism of grain boundary sliding. The discrepancy between the stress exponent in sinterforging and impression creep tests is attributed to the lower stresses employed in the impression creep experiments, suggesting different mechanisms are presumably in operation in the two regimes. The activation energy for impression creep was 1.6 eV, which is explained by accommodation by grain boundary diffusion. Impression creep tests on nanocrystalline Fe produced similar results; the stress exponent was 2 and the activation energy, 0.8 eV, was indicative of grain boundary diffusion.

Transduction and tropism of rAAV6: Implications for gene therapy of neuromuscular disorders

Arnett, Andrea Lee Harper University of Washington 2011 해외박사(DDOD)

Gene delivery vectors derived from adeno-associated virus (AAV) have great potential as therapeutic agents in the treatment of neuromuscular disorders. Recombinant AAV serotype 6 (rAAV6), can efficiently target striated muscle, but the mechanisms that influence tropism and the transduction profile of rAAV6 remain unclear. Additionally, rAAV6 transduction of satellite cells and other muscle progenitor cells has not been well-characterized. In these studies, we evaluated the influence of heparin binding on the tropism of rAAV6 vectors and investigated transduction efficiency in skeletal muscle satellite cells, myoblasts, and regenerating myofibers. Transduction was evaluated both in vitro and in vivo via intracranial (IC), intravenous (IV), and intramuscular (IM) injection in wild type and dystrophic mice. We found that heparin binding influences tissue tropism following systemic injection, and is associated with lower transduction efficiency and restricted dissemination of vector following IC injection. In contrast, heparin binding correlates with increased transduction efficiency in striated muscle, whether delivered by IM or IV injection. Furthermore, we determined that rAAV6 preferentially targets mature myofibers and does not effectively transduce satellite cells in vivo. Cultured MM14 myoblasts were transduced by rAAV6, but with reduced efficiency compared to differentiated myotubes. Consistent with these observations, we found that rAAV6-mediated transgene expression was rapidly lost when the rate of myofiber turnover remained elevated. It was found that the truncated dystrophin isoform, Dp116 does not mechanically contribute to muscle function in severely dystrophic mice or prevent myofiber turnover. Thus, rAAV-mediated expression was rapidly lost from transduced tissues. These data indicate that intrinsic properties of the rAAV6 capsid contribute to efficient transduction of mature skeletal muscle, but suggest that rAAV6-mediated therapies will need to be coordinated with other treatment strategies to effectively target muscle stem cell populations. In addition, we evaluated the immune response to rAAV6 following parvoviral vaccination in mice and canines. We determined that vaccine-induced immunity to canine parvovirus does not significantly impact rAAV6-mediated transduction and found that exposure to rAAV6 in neonatal mice does not induce a tolerant response to re-administration of vector.

Cultivating Inclusion: Navigating Diversity Through Expressing and Concealing Social Identity Differences in Interpersonal Interactions

Arnett, Rachel D Harvard University ProQuest Dissertations & Theses 2018 해외박사(DDOD)

African American church goers' attitudes toward treatment seeking from mental health and religious sources: The role of spirituality, cultural mistrust, and stigma toward mental illness

Brown, John Arnett The University of North Carolina at Chapel Hill 2004 해외박사(DDOD)

Although there has been much research on the relationship of religion to mental health outcomes and willingness to seek treatment, little of that research has focused specifically on spirituality. Some attribute this dearth of research to the lack of a commonly accepted definition of the construct of spirituality as contrasted to other church based experiences, such as participation in church activities. At the same time, there has been a noticeable increase in the number of religiously based mental health programs, particularly within the African American community. The current study aimed to better understand which aspects of African Americans' spiritual lives (i.e., spiritual characteristics, beliefs, actions, and experiences) are related to their willingness to seek treatment from different religious and secular sources: while taking into account some of the potential barriers to seeking treatment for African Americans, including cultural mistrust, stigmatizing views of mental illness, educational access, and financial adequacy. Results indicate that seeking help from religious and mental health sources, respectively, were not distinguished by problem type and severity. However, problem type and severity influenced help seeking from medical sources. Stigma was related to spirituality, but did not mediate a relationship between spirituality and help seeking, as predicted. Spirituality was related to willingness to seeking help from secular mental health professionals, but was not related to help seeking from other sources. In general, this sample of churchgoers preferred religious sources to non-religious sources. The policy and resource allocation implications are discussed, as are directions for future research.

Development of Lithium-Drifted Silicon Detectors and Investigation of Cosmic Antihelium Sensitivity for the Gaps Experiment: An Indirect Search for Dark Matter

Saffold, Nathan Arnett Columbia University ProQuest Dissertations & These 2021 해외박사(DDOD)