1,720,998 research outputs found
High magnesium inhibits human osteoblast differentiation in vitro
No full textSeveral studies in humans indicate that both high and low concentrations of magnesium have harmful effects on bone metabolism and homeostasis. However, little is known about the effects of different concentrations of magnesium on bone cells. Considering that 1mM is the physiological concentration of extracellular magnesium for cultured cells, in our experimental model we exposed osteoblast like SaOS-2 cells and normal human osteoblasts to low (0.1mM) and high (5.0mM) concentrations of magnesium. We found that high concentrations of magnesium markedly inhibited the deposition of mineral matrix by SaOS-2 as well as the activity of alkaline phosphatase, a marker of osteoblast differentiation. We then evaluated the differentiation of normal human osteoblasts by measuring alkaline phosphatase activity and again found a marked inhibition by high concentrations of magnesium. Nitric oxide, which is known to play a role in bone formation, does not seem to be involved. We hypothesize that high levels of magnesium might alter the intracellular concentration of various cations - among which calcium - by competing for the same transporters. We conclude that high magnesium levels impair osteoblast activity and might therefore contribute to bone disease
Effect of homoarginine administration on neointimal thickening in balloon-injured rat carotid arteries
No full textGoing 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
Sympathetic neurotransmission during atherosclerosis development: an unrecognized target of dyslipidemia?
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
Skin morphology in double apoA-I/apoE knock-out mice : a structural and ultrastructural study
No full textApolipoprotein(apo)A-I, the main protein component of high density lipoproteins (HDLs), plays a major role in cholesterol removal from peripheral tissues and increasing evidence supports its function as an important regulator of the immune response (Annema et al., 2013).
The aim of the study was to evaluate the effect of apoA-I deficiency in dyslipidemic mice, when fed a low-fat/low-cholesterol diet. Three lines of male mice were considered: wild-type mice as controls, apoE-KO mice as dyslipidemic model (Zhang et al.,1992) and apoA-I/apoE double KO mice (DKO mice). Whereas in wild-type mice cholesterol circulates almost exclusively in HDLs, apoE-KO mice are hypercholesterolemic and cholesterol mostly circulates in low-density lipoproteins. In DKO mice, cholesterol levels are comparable to wild-type mice, but HDLs are almost absent and cholesterol entirely accumulates in low-density lipoproteins.
In the present study, all animals were maintained on a low-fat/low-cholesterol diet up to 30 weeks of age. At sacrifice, skin biopsies from two different anatomical areas (thoracic and abdominal regions) were harvested from each animal and processed for both light (LM) and transmission electron microscopy (TEM). Whereas the skin of apoE-KO mice was comparable to that of control mice, LM analysis in DKO mice revealed an increase in dermal thickness and a massive presence of foam cells and lymphocytes. TEM analysis showed the presence of cholesterol clefts in the papillary dermis and inside foam cells in the reticular dermis.
In conclusion, our results demonstrate that in DKO mice fed a low-fat/low-cholesterol diet, the lack of apoA-I is responsible for an aberrant skin morphology, with an exacerbated inflammatory response, possibly caused by a local cholesterol accumulation
Deposition of Super-Hydrophobic and Oleophobic Fluorocarbon Films in Radio Frequency Glow Discharges
No full textFluorocarbon films using a monomer, 1H, 1H, 2H-perfluoro–1-dodecene were deposited in a continuous radio frequency (RF) glow discharge, the process was carried out in a parallel-plate RF discharge onto stainless steel reactor in order to produce coating with a water-and oil–repellent surface. Fourier-Transform Infrared spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS) revealed that the films obtained contain mainly perfluoromethylene (CF2) species. Film wettability was tested using water and hydrocarbon liquids for contact angle measurements, furthermore surface energy was also calculated. Oil-repellency was found to increase as the amount of CF2 species increases in the film structure. Film morphology was studied by Atomic Force Microscopy (AFM), films showing an usual morphology from that typical of Plasma Polymerised Fluorocarbon (PPFC) films. The combination of the low surface energy coating and the surface morphology produces materials which are both water and oil repellency
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
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