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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
Thin films of a self-assembling peptide on TiO2 and Au studied by NEXAFS, XPS and IR spectroscopies
No full textEAK16 is a 16 amino acid peptide consisting of an alternation of polar and non-polar pending groups and of positively and negatively charged
residues, that makes this material capable of self-assembling, producing an extended ordered structure.
Thin films of EAK16 were prepared on TiO2 and Au surfaces and investigated by surface-sensitive techniques such as XPS (X-ray
photoelectron spectroscopy), NEXAFS (near edge X-ray absorption fine structure) and IR spectroscopies.
XPS analysis allowed to check the chemical structure of the samples and to determine the film thickness. IR experiments yielded evidence of
the h-sheet conformation of the peptide backbone. Polarization dependent NEXAFS measurements allowed estimating the angle between the axis
of the peptide backbone and the sample surface
A NEXAFS and XPS study of the adsorption of self-assembling peptides on TiO2: the influence of the side chains
No full textPeptides consisting of an alternation of hydrophobic and hydrophilic (positively and negatively charged) amino acids can generate extended ordered structures by self-assembling (SA) from aqueous solutions. In this paper we present XPS, near-edge X-ray absorption fine structure (NEXAFS) and Fourier transform infrared (FTIR) investigations on a series of SA peptides with the aim of determining the effect of side-chain length on molecular arrangement and orientation. Peptides were immobilised on the surface of titanium, a well-known biocompatible material, or deposited as thick films on inert gold surfaces. FTIR analysis yields information on the backbone conformation. XPS spectroscopy was used to investigate the peptide adsorption on the TiO2 surface. The orientation of the peptide chains was investigated by angular-dependent NEXAFS
Strategy to Enhance the osseo-integration Process: Synthetic Peptides Improving Osteoblast Adhesion on Implant Surface
No full textVariations 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
Heparin enhances the furin cleavage of HIV-1 gp160 peptides
No full textInfectious HIV-1 requires gp160 cleavage by furin at
the REKR511fl motif (site1) into the gp120/gp41 complex,
whereas the KAKR503 (site2) sequence remains uncleaved. We
synthesized 41mer and 51mer peptides, comprising site1 and
site2, to study their conformation and in vitro furin processing.
We found that, while the previously reported 19mer and 13mer
analogues represent excellent in vitro furin substrates, the present
extended sequences require heparin for optimal processing.
Our data support the hypothesis of a direct binding of heparin
with site1 and site2, allowing selective exposure/accessibility of
the REKR sequence, which is only then optimally cleaved by furin
Strategy to enhance the osseo-inntegration process: synthetic peptides improving osteoblast adhesion on implant surface
No full textIn order to improve the integration process between surgically placed implants and biological tissues, next generation biomaterials have to be designed to enhance and support osteoblast adhesion. In fact, it has been demonstrated that the quality of the early cell/material interactions is highly responsible for the long-term functional response of implants.
Polystyrene surfaces have been conditioned with different synthetic peptides and their ability in promoting osteoblast adhesion has been compared. The results obtained applying best performing peptides in osteoblast adhesion assays on acellular bone matrix are herewith discussed
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