611 research outputs found
Human protein C concentrate in the treatment of purpura fulminans : a retrospective analysis of safety and outcome in 94 pediatric patients
No full textIntroduction: Purpura fulminans (PF) is a devastating complication of uncontrolled systemic inflammation, associated with high incidence of amputations, skin grafts and death. In this study, we aimed to clarify the clinical profile of pediatric patients with PF who improved with protein C (PC) treatment, explore treatment effects and safety, and to refine the prognostic significance of protein C plasma levels. Methods: In Germany, patients receiving protein C concentrate (Ceprotin(R), Baxter AG, Vienna, Austria) are registered. The database was used to locate all pediatric patients with PF treated with PC from 2002 to 2005 for this National, retrospective, multi-centered study. Results: Complete datasets were acquired in 94 patients, treated in 46 centers with human, non-activated protein C concentrate for purpura fulminans. PC was given for 2 days (median, range 1-24 days) with a median daily dose of 100 IU/kg. Plasma protein C levels increased from a median of 27% to a median of 71% under treatment. 22.3% of patients died, 77.7% survived to discharge. Skin grafts were required in 9.6%, amputations in 5.3%. PF recovered or improved in 79.8%, remained unchanged in 13.8% and deteriorated in 6.4%. Four adverse events occurred in 3 patients, none classified as severe. Non-survivors had lower protein C plasma levels (P < 0.05) and higher prevalence of coagulopathy at admission (P < 0.01). Time between admission and start of PC substitution was longer in patients who died compared to survivors (P = 0.03). Conclusions: This retrospective dataset shows that, compared to historic controls, only few pediatric patients with PF under PC substitution needed dermatoplasty and/or amputations. Apart from epistaxis, no bleeding was observed. Although the data comes from a retrospective study, the evidence we present suggests that PC had a beneficial impact on the need for dermatoplasty and amputations, pointing to the potential value of carrying out a prospective randomised controlled trial
Playing with nonuniform grids
No full textNumerical experiments with discretization methods on nonuniform grids are presented for the convection-diffusion equation. These show that the accuracy of the discrete solution is not very well predicted by the local truncation error. The diagonal entries in the discrete coefficient matrix give a better clue: the convective term should not reduce the diagonal. Also, iterative solution of the discrete set of equations is discussed. The same criterion appears to be favourable.
Novel genetic environment of plasmid-mediated quinolone resistance gene qnrB2 in Salmonella Bredeney from poultry
No full textA new calculation of the wake of a flat plate
No full textA new method is presented for the calculation of the wake of a finite flat plate. The method is based upon the recent investigations of the boundary layer near the trailing edge, which led to the triple-deck structure. This multi-layered structure has now been extended to the "classical" wake, which in fact is the continuation of the lowest two layers of the triple-deck. With this new numerical formulation an accuracy of 10-3% can easily be achieved.
Direct numerical simulation of turbulence at lower costs
No full textDirect Numerical Simulation (DNS) is the most accurate, but also the most expensive, way of computing turbulent flow. To cut the costs of DNS we consider a family of second-order, explicit one-leg time-integration methods and look for the method with the best linear stability properties. It turns out that this method requires about two times less computational effort than Adams–Bashforth. Next, we discuss a fourth-order finite-volume method that is constructed as the Richardson extrapolate of a classical second-order method. We compare the results of this fourth-order method and the underlying second-order method for a DNS of the flow in a cubical driven cavity at Re = 10^4. Experimental results are available for comparison. For this example, the fourth-order results are clearly superior to the second-order results, whereas their computational effort is about twenty times less. With the improved simulation method, a DNS of a turbulent flow in a cubical lid-driven flow at Re = 50,000 and a DNS of a turbulent flow past a square cylinder at Re = 22,000 are performed.
Brill and Open Access
No full textAn online conversation with two representatives of Brill, a publisher that is particularly strong in the Humanities and Social Sciences. A 340-year-old publishing house, Brill still primarily sells books and journals in a traditional manner, i.e. as hardcopies and online fulltexts behind a paywall. Currently, Brill has a total output of around 1,400 academic books per year. Just over 10% of these titles are published in Open Access thanks to authors (or their institutions) paying a Book Processing Charge (BPC). Among its 300+ peer-reviewed journals, approx. 10% are published according to the Diamond Open Access model, meaning that some sort of sponsorship allows Brill to offer its services with no author- or reader-facing charges. In the discussion, Open Research Officer Stephanie Veldman explains the economic mechanisms and strategic thinking behind Brill’s work in the field of open access. Publishing director for History, Social Sciences and Biology Arjan van Dijk highlights the author’s and editor’s perspectives, using the successful Journal of Jesuit Studies (launched in 2013) as a concrete example. Both Veldman and van Dijk see it as an important part of their mission to increase the proportion of books and journals that are published in open access.
First published online: June 7, 2023
Numerical Simulation of a Turbulent Flow in a Channel with Surface Mounted Cubes
No full textIn this paper we report on a fourth-order, spectro-consistent simulation of a complex turbulent flow. A spatial discretization of a convection-diffusion equation is termed spectro-consistent if the spectral properties of the convective and diffusive operators are preserved, i.e. convection ↔ skew-symmetric; diffusion ↔ symmetric positive definite. We consider a fully developed flow in a channel, where a matrix of cubes is placed at a wall of the channel. The Reynolds number (based on the channel width and the mean bulk velocity) is equal to Re = 13,000. The three-dimensional flow around the surface mounted cubes has served at a test case at the 6th ERCOFTAC/IAHR/COST workshop on refined flow modeling (Delft, June 1997). Here, mean velocity profiles as well as Reynolds stresses at various locations in the channel have been computed without using any turbulence models. The results agree well with the available experimental data.
Corrigendum: Editorial: Sex and gender effects on power, status, dominance, and leadership – an interdisciplinary look at human and other mammalian societies
No full textIn the published article, there was an error in Research investigating sex effects in non-human mammals, paragraph 5. We omitted a few words in two places of the same sentence. The sentence previously stated: “Several papers in this Research Topic investigated whether the degree of dominance of females over males depends on morphological, demographic or ecological factors such as relative body size, adult sex ratio, sexual maturity or mating season.” The corrected sentence appears below: “Several papers in this Research Topic investigated whether the degree of dominance of females over males depends on morphological, demographic, ecological or social factors such as relative body size, adult sex ratio, sexual maturity, mating season or social support.” In the published article, there was an error in Research investigating sex effects in non-human mammals, paragraph 7. We omitted a full sentence citing the results of one study of the Research Topic. This sentence previously stated: “Conversely, Koenig et al. show in wild gray langurs that male dominance appears inflexible across contexts, and that the rare events of female aggression toward males are aimed at infant protection, while most male aggression towards females occur in a feeding context. This work suggests that intersexual feeding competition may contribute to shaping male-female relationships.” The corrected sentence appears below: “Conversely, Koenig et al. show in wild gray langurs that male dominance appears inflexible across contexts, and that the rare events of female aggression toward males are aimed at infant protection, while most male aggression towards females occur in a feeding context. This work suggests that intersexual feeding competition may contribute to shaping male-female relationships. Moreover, McCormick et al. report support for the idea that sex differences in agonistic behavior as well as in social support both mediate female dominance over males in clans of spotted hyenas, even though adult females can often dominate immigrant males without any support.” In the published article, there was an error in Research investigating sex effects in non-human mammals, paragraph 8. A couple of words need to be changed to the following sentence to avoid repeats arising from the inserted sentence. This sentence previously stated: “Finally, in the female-dominated society of spotted hyenas, East et. al., show that male fitness is substantially affected by the loss of offspring due to infanticide by females.” The corrected sentence appears below: “Finally, also in spotted hyenas, East et al. show that male fitness is substantially affected by the loss of offspring due to infanticide by females.” The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.</p
Characterization of plasmids harbouring qnrS1, qnrB2 and qnrB19 genes in Salmonella
No full textThe aim of this study was to identify and characterize plasmids carrying qnrS1, qnrB2 and qnrB19 genes identified in Salmonella strains from The Netherlands. The identification of plasmids may help to follow the dissemination of these resistance genes in different countries and environments. Plasmids from 33 qnr-positive Salmonella strains were transferred to Escherichia coli and analysed by restriction, Southern blot hybridization, PCR and sequencing of resistance determinants. They were also assigned to incompatibility groups by PCR-based replicon typing, including three additional PCR assays for the IncU, IncR and ColE groups. The collection included isolates from humans and one from chicken meat. Five IncN plasmids carrying qnrS1, qnrB2 and qnrB19 genes were identified in Salmonella enterica Bredeney, Typhimurium PT507, Kentucky and Saintpaul. qnrS1 genes were also located on three further plasmid types, belonging to the ColE (in Salmonella Corvallis and Anatum), IncR (in Salmonella Montevideo) and IncHI2 (in Salmonella Stanley) groups. Multiple events of mobilization, transposition and replicon fusion generate the complexity observed in qnr-positive isolates that are emerging worldwide. Despite the fact that the occurrence of qnr genes in bacteria from animals is scarcely reported, these genes are associated with genetic elements and located on plasmids that are recurrent in animal isolates
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