1,720,957 research outputs found
‘Transformation of amyloid-like fibres, formed from an elastin-based biopolymer, into hydrogel: an XPS and AFM study’
No full textPrevious studies have revealed the propensity of elastin-based biopolymers to form amyloid-like fibers when dissolved in water. These are of interest when considered as "ancestral units" of elastin in which they represent the simplest sequences in the hydrophobic regions of the general type XxxGlyGlyZzzGly (Xxx, Zzz = Val, Leu). We normally refer to these biopolymers based on elastin or related to elastin units as "elastin-like polypeptides". The requirement of water for the formation of amyloids seems quite interesting and deserves investigation, the water representing the natural transport medium in human cells. As a matter of fact, the "natural" supramolecular organization of elastin is in the form of beaded-string-like filaments and not in the form of amyloids whose "in vivo" deposition is associated with some important human diseases. Our work is directed, therefore, to understanding the mechanism by which such hydrophobic sequences form amyloids and any conditions by which they might regress to a non-amyloid filament. The elastin-like sequence here under investigation is the ValGlyGly ValGly pentapeptide that has been previously analyzed both in its monomer and polymer form. In particular, we have focused our investigation on the apparent stability of amyloids formed from poly(ValGlyGlyValGly), and we have observed these fibers evolving to a hydrogel after prolonged aging in water. We will show how atomic force microscopy can be combined with X-ray photoelectron spectroscopy to gain an insight into the spontaneous organization of an elastin-like polypeptide driven by interfacial interactions. The results are discussed also in light of fractal-like assembly and their implications from a biomedical point of view
Achievement of near-normal body weight as the prerequisite to normalize sexhormone-binding globulin concentrations in massively obese men.
No full textOBJECTIVE: To investigate the effects of weight loss on sex hormone-binding
globulin (SHBG) in massively obese males and whether normal SHBG concentrations
could be obtained regardless or not of the achievement of normal body weight
values.
DESIGN AND SUBJECTS: Sera were collected for SHBG determination from 63 massively
obese men, partly before they underwent biliopancreatic diversion (pre-op group =
11) and partly during the post-surgical follow up (post-op group = 52), and
twenty normal weight healthy control men.
MEASUREMENTS: Serum SHBG was measured using a noncompetitive liquid-phase
immunoradiometric assay.
RESULTS: Baseline general characteristics were similar in both obese groups.
Obese patients in the post-op group had lost 46.4 +/- 2.9 kg since they had
undergone operation, namely during a mean period of 14.9 +/- 13.8 (range 1-58)
months follow up. Obese groups had significantly lower SHBG than normal weight
controls (66.2 +/- 18.6 nmol/l). However, pre-op obese (19.9 +/- 5.5 nmol/l) had
significantly lower values than post-op obese subjects (45.5 +/- 24.8 nmol/l; P <
0.001). There were a highly significant correlation between SHBG and individual
BMI values (r = -0.629; P < 0.001). Moreover, the post-op obese with BMI values
lower or equal to 28 had significantly higher SHBG concentrations than those with
BMI greater than 28 (62.8 +/- 22.2 nmol/l vs 32.1 +/- 19.6 nmol/l; P < 0.001),
but not significantly different with respect to normal weight controls.
CONCLUSIONS: Massively obese men weight loss can completely reverse SHBG
abnormalities, which can be restored to the normal range when near-normal body
weight is achieved. Since reduced SHBG concentrations can be an independent risk
factor for the development of diabetes and cardiovascular disease, this
represents an additional benefit of weight loss program in massively obese
individuals
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
