1,720,991 research outputs found
Pathophysiology of the human locus coeruleus complex in fetal/neonatal sudden unexplained death
No full textObjectives: We investigated the locus coeruleus complex in the brainstems of 78 subjects aged from 24 gestational weeks to 8 postnatal months, who died of unknown (sudden unexplained fetal and infant deaths) and known causes (controls). The goals of this study were: (1) to obtain basic information about the morphology of the locus coeruleus complex and the expression of different biological parameters (tyrosine hydroxylase, neuromelanin and apoptosis) during the first phases of human nervous system development; (2) to evaluate possible alterations of this structure in victims of sudden death; and (3) to verify any correlation with risk factors.
Methods: All the victims were subjected to a complete autopsy, including an in-depth histological examination of the autonomic nervous system and in particular of the locus coeruleus complex, the target of this study. Adrenergic neurons were identified by tyrosine hydroxylase (TH) immunohistochemistry and neuromelanin-containing neurons were specifically visualized by the application of Lillie’s method. In addition, the activation of programmed cell death (apoptosis) was studied by investigating DNA fragmentation (TUNEL-positive cells).
Results: Alterations of the noradrenaline system, decreased neuromelanin, hypoplasia, in addition to a high neuronal death rate, were observed almost exclusively in the locus coeruleus complex of fetal and infant sudden deaths, and were significantly correlated to maternal smoking.
Discussion: The developmental defects found in the locus coeruleus complex in victims of sudden unexplained fetal and infant death imply alterations of the vital activities related to the widespread brain connections arising from this neuronal center, including coordination of the sleep–waking cycle and control of the cardio-respiratory system
Sudden unexpected infant and perinatal death: Pathological findings of the cardiac conduction system
Full text linkObjective Sudden infant death syndrome (SIDS), sudden neonatal unexpected death (SNUD), and sudden intrauterine unexpected death (SIUD) are major unsolved, shocking form of death that occur frequently and can happen at any time without warning. The body of literature on the anatomo-pathological substrates in the cardiac conduction system of SIDS-SIUD and their possible relationship with risk factors and triggers is fragmentary and scarce. The main objective of this work is to analyze the cardiac conduction system findings collected at the national referral center for SIDS-SIUD.
Methods A total of 123 autopsied cases of SIDS (59.35% males, 40.65% females, mean age ± SD: 103.49 ± 67.17 days), 36 cases of SNUD (61.11% males, 38.89% females, mean age ± SD: 8.4 ± 9.17 days), and 127 cases of SIUD (45.67% males, 54.33% females, mean age ± SD: 36 ± 4.59 gestational weeks) were analyzed. In-depth pathological examinations of the cardiac conduction system were performed on serial sections according to the Lino Rossi Research Center's protocol.
Results Among the studied cases, the following findings were observed: resorptive degeneration (SIDS: 88.7%, SNUD: 88.88%, SIUD: 56.69%), fetal dispersion (SIDS: 73.17%, SNUD: 91.66%, SIUD: 78.74%), Mahaim fibers (SIDS: 40.65%, SNUD: 44.44%, SIUD: 32.28%), cartilaginous meta-hyperplasia (SIDS: 56.91%, SNUD: 25%, SIUD: 33.07%), septated atrio-ventricular junction (AVJ) (SIDS: 21.14%, SNUD: 33.33%, SIUD: 38.58%), AVJ duplicity (SIDS: 6.5%, SNUD: 11.11%, SIUD: 2.36%), intramural bifurcation (SIDS: 3.25%, SNUD: 2.77%, SIUD: 4.72%), without significant differences.
Conclusions The prevalence of cardiac conduction findings was consistent across the SIDS, SNUD and SIUD groups. These findings provide valuable insights into the pathological characteristics of the cardiac conduction system in SIDS-SIUD that might be potential morphological substrates for the development of cardiac arrhythmias. Further investigation and study of the conduction system are needed to understand the underlying mechanisms of these forms of death
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
Effetto del lievito naturale e delle fibre alimentari sull’indice glicemico dei prodotti lievitati da forno
No full textUnsuspected imported malaria in a case of sudden infant death
No full textHere we describe the case of a 4-mo-old female who
died suddenly without any apparent cause that was
initially mistaken as a case of sudden infant death syn
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drome. Histologic observation of brain sections revealed
blue-black bodies in erythrocytes of the blood vessels,
suggestive of specific stages of the hematic schizogonic
cycle. Further examinations revealed hemozoin and
hemosiderin deposits in the parenchyma of all organs,
leading to the diagnosis of malaria by Plasmodium falci
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parum (P. falciparum). The death occurred in Italy, the
native country of the infant, two weeks after a Christ-
mas holiday spent in Pakistan, the parents’ birthplace,
which has a high malarial endemicity. As this case
demonstrates, the diagnosis of malaria should always
be considered as a differential diagnosis in subjects,
including infants, that die unexpectedly after returning
from P. falciparum endemic area
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
A wavenumber parallel computational code for the numerical integration of the Navier-Stokes equations
No full textA parallel computational code for the numerical integration of the Navier–Stokes equations has been developed. The system of partial differential equations describing the non-steady flow of a viscous incompressible fluid in three dimensions is considered and applied to the channel flow problem. A mixed spectral-finite difference technique for the numerical integration of the governing equations is devised: Fourier decomposition in both streamwise and spanwise directions and finite differences in the direction orthogonal to the solid walls are used, while a semi-implicit procedure of Runge–Kutta and Crank–Nicolson type is utilised for the advancement in time. A wavenumber parallelism is implemented for the execution of the calculations. Within each time step of integration, the computations are executed in two distinct phases, each phase corresponding to a different way of decomposing the computational domain, vertically and horizontally, respectively; in both phases of the whole calculation process, each portion of the computing domain is handled by a different CPU on a Convex SPP 1200/XA parallel computing system. Results are presented in terms of performance of the calculation procedure with the use of 2,4,6 and 8 processors respectively and are compared with the single-processor performance. Also the accuracy of the parallel algorithm has been tested, by analysing the evolution in time of small amplitude disturbances of the mean flow; a satisfactory agreement with the theoretical solution given by the hydrodynamic stability theory is found, provided that a given number of grid points in the y direction are present
Implementation of a Navier-Stokes solver on a parallel computing system
No full textNavier Stokes, Numerical Integration, Parallel Algorith
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