15,279 research outputs found
The Perception of Library and Information Science Journals by LIS Education Deans and ARL Library Directors: A Replication of the Kohl-Davis Study
Analyzing the collective opinion of presumed experts, often termed a per-
ception study, is a frequently used approach for rating journals or evaluating
education programs. Replicating the 1985 Kohl–Davis study, seventy-one
library and information science (LIS) journals are ranked according to their
mean rating on a 1 to 5 ordinal scale by deans of ALA-accredited educa-
tion programs and by the directors of ARL libraries (surveyed during the
summer of 2003). Comparison of the results with the 1985 study found
considerable continuity in journal perceptions over the past two decades,
but more so by directors than deans. A weak to moderate correlation was
found between deans’ ratings and Journal Citation Reports citation scores,
whereas the correlations between directors’ perceptions and citation data
were weak to nonexistent. The findings confirm a hierarchy of prestige
among LIS journals, but the hierarchical order differs somewhat between
deans and directors
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An Analysis Technique for Layered Manufacturing Based on Quasi-Wavelet Transforms
An analysis technique based on the Wavelet transform (WT) has been recently introduced
that allows the spatial frequency content of objects produced by layered manufacturing (LM)
techniques to be interpreted in terms ofmanufacturable features. (Lee and Thomas, 1997) Using
Haar's wavelet as a basis function, layers with vertical edges are modeled exactly. Using
analysis, a 3D model can be transformed, filtered, and inverse transformed resulting in an image
ofthe part as it would look if constructed from layers of a specific thickness. In order to extend
this analysis to construction techniques using higher order edges (ruled surface edges or curved
edges), the quasi-wavelet transform (QWT) is introduced. QWT analysis is conceptually the
same as WT analysis, except that the basis function can be selected by the user, allowing exact
analysis of layered manufacturing techniques using higher order construction algorithms. This
work is supported by a grant from the University ofUtah Research Foundation.Mechanical Engineerin
Shock wave-boundary layer interactions in laminar transonic flow.
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76478/1/AIAA-1973-239-112.pd
Perturbed cholesterol and vesicular trafficking associated with dengue blocking in Wolbachia-infected Aedes aegypti cells
Wolbachia are intracellular maternally inherited bacteria that can spread through insect populations and block virus transmission by mosquitoes, providing an important approach to dengue control. To better understand the mechanisms of virus inhibition, we here perform proteomic quantification of the effects of Wolbachia in Aedes aegypti mosquito cells and midgut. Perturbations are observed in vesicular trafficking, lipid metabolism and in the endoplasmic reticulum that could impact viral entry and replication. Wolbachia-infected cells display a differential cholesterol profile, including elevated levels of esterified cholesterol, that is consistent with perturbed intracellular cholesterol trafficking. Cyclodextrins have been shown to reverse lipid accumulation defects in cells with disrupted cholesterol homeostasis. Treatment of Wolbachia-infected Ae. aegypti cells with 2-hydroxypropyl-β-cyclodextrin restores dengue replication in Wolbachia-carrying cells, suggesting dengue is inhibited in Wolbachia-infected cells by localised cholesterol accumulation. These results demonstrate parallels between the cellular Wolbachia viral inhibition phenotype and lipid storage genetic disorders
Mutations in hepatitis C virus E2 located outside the CD81 binding sites lead to escape from broadly neutralizing antibodies but compromise virus infectivity.
Broadly neutralizing antibodies are commonly present in the sera of patients with chronic hepatitis C virus (HCV) infection. To elucidate possible mechanisms of virus escape from these antibodies, retrovirus particles pseudotyped with HCV glycoproteins (HCVpp) isolated from sequential samples collected over a 26-year period from a chronically infected patient, H, were used to characterize the neutralization potential and binding affinity of a panel of anti-HCV E2 human monoclonal antibodies (HMAbs). Moreover, AP33, a neutralizing murine monoclonal antibody (MAb) to a linear epitope in E2, was also tested against selected variants. The HMAbs used were previously shown to broadly neutralize HCV and to recognize a cluster of highly immunogenic overlapping epitopes, designated domain B, containing residues that are also critical for binding of viral E2 glycoprotein to CD81, a receptor essential for virus entry. Escape variants were observed at different time points with some of the HMAbs. Other HMAbs neutralized all variants except for the isolate 02.E10, obtained in 2002, which was also resistant to MAb AP33. The 02.E10 HCVpp that have reduced binding affinities for all antibodies and for CD81 also showed reduced infectivity. Comparison of the 02.E10 nucleotide sequence with that of the strain H-derived consensus variant, H77c, revealed the former to have two mutations in E2, S501N and V506A, located outside the known CD81 binding sites. Substitution A506V in 02.E10 HCVpp restored binding to CD81, but its antibody neutralization sensitivity was only partially restored. Double substitutions comprising N501S and A506V synergistically restored 02.E10 HCVpp infectivity. Other mutations that are not part of the antibody binding epitope in the context of N501S and A506V were able to completely restore neutralization sensitivity. These findings showed that some nonlinear overlapping epitopes are more essential than others for viral fitness and consequently are more invariant during earlier years of chronic infection. Further, the ability of the 02.E10 consensus variant to escape neutralization by the tested antibodies could be a new mechanism of virus escape from immune containment. Mutations that are outside receptor binding sites resulted in structural changes leading to complete escape from domain B neutralizing antibodies, while simultaneously compromising viral fitness by reducing binding to CD81
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