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Structural insights into alternate aggregated prion protein forms
No full textThe conversion of the cellular form of the prion protein (PrP(C)) to an abnormal, alternatively folded isoform (PrP(Sc)) is the central event in prion diseases or transmissible spongiform encephalopathies. Recent studies have demonstrated de novo generation of murine prions from recombinant prion protein (recPrP) after inoculation into transgenic and wild-type mice. These so-called synthetic prions lead to novel prion diseases with unique neuropathological and biochemical features. Moreover, the use of recPrP in an amyloid seeding assay can specifically detect and amplify various strains of prions. We employed this assay in our experiments and analyzed in detail the morphology of aggregate structures produced under defined chemical constraints. Our results suggest that changes in the concentration of guanidine hydrochloride can lead to different kinetic traces in a typical thioflavin T(ThT) assay. Morphological and structural analysis of these aggregates by atomic force microscopy indicates a variation in the structure of the PrP molecular assemblies. In particular, ThT positive PrP aggregates produced from rec mouse PrP residues 89 to 230 lead to mostly oligomeric structures at low concentrations of guanidine hydrochloride, while more amyloidal structures were observed at higher concentrations of the denaturant. These findings highlight the presence of numerous and complex pathways in deciphering prion constraints for infectivity and toxicity
Le sostanze umiche inibiscono la formazione di fibrille e l'internalizzazione cellulare della forma b della proteina prionica
No full textAnalytical evaluation of the role of estimation and quantization errors in downstream vectored VDSL systems
No full textSimple statistical analysis of the impact of some nonidealities in downstream VDSL with linear precoding
No full textProtein Aggregation Measurement through Electrical Impedance Spectroscopy
Full text linkThe paper presents a novel methodology to measure the fibril formation in protein solutions. We designed a bench consisting of a sensor having interdigitated electrodes, a PDMS hermetic reservoir and an impedance meter automatically driven by calculator. The impedance data are interpolated with a lumped elements model and their change over time can provide information on the aggregation process. Encouraging results have been obtained by testing the methodology on K-casein, a protein of milk, with and without the addition of a drug inhibiting the aggregation. The amount of sample needed to perform this measurement is by far lower than the amount needed by fluorescence analysis
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
The interaction of humic substances with the human prion protein fragment 90-231 affects its protease K resistance and cell internalization.
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