1,721,262 research outputs found
Amyloid fibrils length controls shape and structure of nematic and cholesteric tactoids
No full textAmyloid fibrils offer the possibility of controlling their contour length, aspect ratio, and length distribution, without affecting other structural parameters. Here we show that a fine control in the contour length distribution of β-lactoglobulin amyloid fibrils, achieved by mechanical shear stresses of different levels, translates into the organization of tactoids of different shapes and morphologies. While longer fibrils lead to highly elongated nematic tactoids in an isotropic continuous matrix, only sufficiently shortened amyloid fibrils lead to cholesteric droplets. The progressive decrease in amyloid fibrils length leads to a linear decrease of the anchoring strength and homogeneous tactoid → bipolar tactoid → cholesteric droplet transitions. Upon fibrils length increase, we first find experimentally and predict theoretically a decrease of the cholesteric pitch, before full disappearance of the cholesteric phase. The latter is understood to arise from the decrease of the energy barrier separating cholesteric and nematic phases over thermal energy for progressively longer, semiflexible fibrils
Unraveling gelation kinetics, arrested dynamics and relaxation phenomena in filamentous colloids by photon correlation imaging
Get PDFISSN:1744-683XISSN:1744-6848ISSN:1744-684
Application of gold nanoparticles embedded in the amyloids fibrils as enhancers in the laser induced breakdown spectroscopy for the metal quantification in microdroplets
No full textIn this work Nanoparticle Enhanced Laser Induced Breakdown Spectroscopy (NELIBS) has been employed for quantitative metal detection using amyloid fibrils coated with gold nanoparticles as enhancers. Amyloid fibrils represent, from one hand, an extremely interesting system for novel technologies, ranging from water purification to medical applications, and on the other hand, an ideal system for investigating the performance of laser-matter interaction in biological systems. The results obtained in this work show the potentiality of NELIBS for the quantification at sub-ppm (mg/kg) level of metallic elements (Cr, Pb, Tl and Cd) even in the protein and/or biological environment, employing amyloid fibrils with gold nanoparticles. Moreover, the single-shot measurements reveal the promising use of this technique in applications where high sensitivity and/or limitation in the sample amount are demanded
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Engineering bio-pharmaceutical micro- and nano-particles using supercritical carbon dioxide as anti-solvent
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