1,721,031 research outputs found
Magnesium supplementation in obstetrics and gynaecology: A brief review
Full text linkMagnesium (Mg), is the second most important intracellular cation. It has been recognized as a cofactor for more than 325 enzymatic reactions involved in a) protein, DNA and RNA synthesis, b) fat, carbohydrates and protein metabolism, and c) cellular energy production and storage. It is essential for the regulation of muscular contraction, blood pressure, insulin metabolism, cardiac excitability, vasomotor tone, nerve transmission and neuromuscular conduction. On these grounds, the possible therapeutic properties of Mg have been investigated in almost every medical field includ-ing Obstetrics and Gynecology, namely exploring oral supple-mentation. The aim of this study is to briefly review existing evidences on the clinical effects of Mg treatment in perinatology as well as in non-pregnant women. During pregnancy, there is a 15% decrease of Mg circulating levels together with a concomitant 25% increase of urinary excretion. Mg supplementation on blood pressure had few impact while it is useful for the alleviation of uterine hyper-activity. Parenteral administration is a standard for the prophylaxis of Eclampsia as well as for neural protection of early preterm baby. A number of studies highlighted a positive correlation between oral magnesium and relief/ prevention of premenstrual syndrome, dysmenorrhea, and postmenopausal symptoms, thus suggesting that magnesium supplementation may repre-sent a valid treatment for these conditions
The anodic oxidation of titanium and its alloys
No full textTitanium is naturally covered with a nanometric oxide film (TiO2) that accounts for most of its industrial applications, where corrosion resistance is the key property. In functional applications, like biomedical devices, photocatalytic reactors, water splitting, and more, focus is set on the TiO2 film characteristics. Anodic oxidation allows obtaining a variety of oxide features-amorphous or crystalline, nanometers micrometers thick, doped with other elements or ions, with surface texturing at the micro or nanoscale. Controlling TiO2 surface properties can not only drastically improve the material efficiency in existing applications but also broaden its fields of use; therefore, an increasing control on production methods is necessary. This article is intended to provide an overview of the anodic oxidation techniques with specific reference to titanium anodizing, and to describe the mechanisms of widely diffused anodic processes, focusing on the resulting oxide features
Towards a better preservation of current and future outdoor architectural heritage; maximum suppression of discolouration in anodized and non-anodized titanium sheets
No full textOutdoor atmospheric corrosion has been exerting continuous deteriorating effects on the cultural heritage, both in the matter of structural resistance and aesthetic quality. To this point, titanium as a modern metal with excellent mechano-physical properties, especially high strength, light weight, superior corrosion resistance has already gained many attentions in different engineering and design fields. In addition to its high atmospheric corrosion resistance, titanium sheets ability to provide a wide range of tasteful colours with high aesthetic quality have paved their way towards the field of modern art and architecture, to the point that its use for monuments and especially as faÁade material for exterior cladding design has been continuously increasing. On the other hand, the undesired growth of this titanium dioxide layer due to long-term exposure in harsh atmospheric conditions leads to the appearance of interference colours and spoils the building from the viewpoint of aesthetic appearance. In particular, acidity of the rainwater falls and its reaction with the impurities present on the surface of titanium sheets to eventually alter the thickness of the oxide film is the main cause of discolouration. This review provides a conceptual framework on different manufacturing issues which have to be precisely taken into consideration in order to minimize the presence of impurities on both anodized and non-anodized end-products, as well as principles of anodizing process to increase the thickness of the oxide layer in order to eventually limit the access of acid rains to the remaining impurities
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
Properties and photocatalytic applications of black TiO2 produced by thermal or plasma hydrogenation
Full text link3D printing of photocatalytic nanocomposites containing titania nanoparticles
Full text linkTitanium dioxide is a semiconductor ceramic material presenting notable electronic and physico-chemical properties. Its anatase form is characterized by excellent photocatalytic properties in presence of UV light, which justify its use for pollutants degradation or for the realization of self-cleaning surfaces. The potential of titania can be further valorized by integrating its unique properties in 3D printed parts and the most promising technology to do this, in consideration of its high resolution and flexibility, is vat photopolymerization. In the present work, titania/polymer composites are 3D printed using this technology and the resulting materials, containing nominal titania amounts up to 10% wt., are characterized from the morphological, microstructural and mechanical point of view. In addition, their photocatalytic activity is evaluated by performing Rhodamine B degradation tests under UV light. The composites showed remarkable activity levels, with a rate constant higher than 0.25 h-1 for the composite containing 10% wt. titania. Activity was increased by a local enrichment of TiO2 in correspondence of the surface, resulting from the 3D printing process, and by a partial degradation of the polymer present between the titania particles in proximity of the surface
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
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