1,720,962 research outputs found
Oxidative stress in neonatology: a review.
No full textFree radicals are highly reactive oxidizing agents containing one or more unpaired electrons. Both in human and veterinary neonathology, it is generally accepted that oxidative stress functions as an important catalysator of neonatal disease. Soon after birth, many sudden physiological and environmental conditions make the newborn vulnerable for the negative effects of oxidative stress, which potentially can impair neonatal vitality. As a clinician, it is important to have in depth knowledge about factors affecting maternal/neonatal oxidative status and the cascades of events that enrol when the neonate is subjected to oxidative stress. This report aims at providing clinicians with an up-to-date review about oxidative stress in neonates across animal species. It will be emphasized which handlings and treatments that are applied during neonatal care or resuscitation can actually impose oxidative stress upon the neonate. Views and opinions about maternal and/or neonatal antioxydative therapy will be shared
Oxidative Stress During Pregnancy In The Sheep.
Full text linkDuring physiological pregnancy, all tissues and, mostly, placenta and foetus require high amounts of oxygen. Reactive oxygen species (ROS), generated both by mother and foetus, are implicated in foetal growth because they promote replication, differentiation and maturation of cells and organs. Nevertheless, ROS excess, if not properly counterbalanced, may lead to an alteration in cell constituents, with harmful effects both on mother and foetus.ROS exert a biphasic effect because adequate ROS concentration is essential for embryo development, implant, foetal defence against uterine infections, steroidogenesis, pregnancy maintainance and partum. On the other hand, an uncontrolled ROS generation, beyond physiological antioxidant defences, may lead to embryo resorption, placental degeneration with subsequent alteration in maternal-foetal exchanges, delay in foetal growth, pregnancy interruption, stillbirths. This review investigates the mechanisms underlying ROS generation and effects, throughout physiological and pathological pregnancy in sheep, with a look to antioxidants and their importance in such a critical phase of the reproductive cycle of the sheep
Evaluation of serum concentrations of interleukin (IL)-4, IL-10, and IL-12 during pregnancy in bitches
No full textComplex cytokine networks play an important role in a wide range of pregnancy-related
processes. During physiological pregnancy, the balance of T helper lymphocytes Th1 and
Th2 is strongly shifted toward Th2, which has a protective role in the feto–maternal
interaction. The aim of the present study is to establish the serum concentrations, ranges,
and trends of anti-inflammatory interleukin (IL)-4 and IL-10, and inflammatory IL-12A,
during three phases of gestation in the bitch (20–30, 31–40, and 41–57 days of gestation).
Our results indicate that, in early gestation, IL-4 and -10 serum concentrations are
elevated and might depend on progesterone that could act as a potent inhibitor of Th1
responses inducing, conversely, the production of Th2-type cytokines (i.e., IL-10 and IL-4).
On the other hand, between 30 and 40 days of gestation, the concentrations of the antiinflammatory
ILs decrease probably because of high concentrations of prolactin, which
is endowed with immunostimulatory properties on different immune cell types. In the
third phase of gestation (41–57 days), an increase in IL-10 occurs, which might depend on
high levels of 17b-estradiol that, during pregnancy, interfere with the ability of dendritic
cells to stimulate T lymphocytes, acting as an anti-inflammatory factor. Conversely, the low
and persistent concentrations of inflammatory IL-12A, throughout pregnancy, compared
with anti-inflammatory ILs, might depend on the characteristic cytokine products of Thl
and Th2 cells that are known to be mutually inhibitory. The monitoring of immunological
status via the levels of cytokines during pregnancy in the bitch, could represent a diagnostic
tool to predict and/or prevent pregnancy abnormality, as demonstrated in wome
Postpartum della bovina da latte: impatto della somministrazione di vitamina A ed E sulle concentrazioni sieriche di ormoni tiroidei.
No full textGoing 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
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