85 research outputs found
Numerical Reconstruction of Ejector Rocket Experimental Tests
Air ejector rocket systems, typical of combined cycle engines for space propulsion applications, have been studied within the ESA Future European Space Transportation Investigations Program. The description and validationof the computational fluid dynamics (CFD) algorithm that has been tuned to simulate the behavior of these systems, and the numerical rebuilding of the ejector rocket experimental tests that were carried out at TNO in The Netherlands are given. The computational developments being presented target the problem of turbulent mixing layer simulation, which is one of the leading phenomena that govern flow behavior inside an ejector rocket. Comparison between experimental and CFD data is given for two validation test cases: a two-dimensional turbulent mixing layer and an axysimmetric ejector in cold flow. Then, the numerical rebuilding of the ejector rocket experimental tests is presented, and the results are discussed with regard to the comparison between numerical and experimental data
Intensive care unit discharge to the ward with a tracheostomy cannula as a risk factor for mortality: A prospective, multicenter propensity analysis
To analyze the impact of decannulation before intensive care unit
discharge on ward survival in nonexperimental conditions. DESIGN: Prospective,
observational survey. SETTING: Thirty-one intensive care units throughout Spain.
PATIENTS: All patients admitted from March 1, 2008 to May 31, 2008.
INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: At intensive care unit
discharge, we recorded demographic variables, severity score, and intensive care
unit treatments, with special attention to tracheostomy. After intensive care
unit discharge, we recorded intensive care unit readmission and hospital
survival. STATISTICS: Multivariate analyses for ward mortality, with Cox
proportional hazard ratio adjusted for propensity score for intensive care unit
decannulation. We included 4,132 patients, 1,996 of whom needed mechanical
ventilation. Of these, 260 (13%) were tracheostomized and 59 (23%) died in the
intensive care unit. Of the 201 intensive care unit tracheostomized survivors, 60
were decannulated in the intensive care unit and 141 were discharged to the ward
with cannulae in place. Variables associated with intensive care unit
decannulation (non-neurologic disease [85% vs. 64%], vasoactive drugs [90% vs.
76%], parenteral nutrition [55% vs. 33%], acute renal failure [37% vs. 23%], and
good prognosis at intensive care unit discharge [40% vs. 18%]) were included in a
propensity score model for decannulation. Crude ward mortality was similar in
decannulated and nondecannulated patients (22% vs. 23%); however, after
adjustment for the propensity score and Sabadell Score, the presence of a
tracheostomy cannula was not associated with any survival disadvantage with an
odds ratio of 0.6 [0.3-1.2] (p=.1). CONCLUSION: In our multicenter setting,
intensive care unit discharge before decannulation is not a risk factor
Dengue Virus Infection of the Aedes aegypti Salivary Gland and Chemosensory Apparatus Induces Genes that Modulate Infection and Blood-Feeding Behavior
The female Aedes aegypti salivary gland plays a pivotal role in bloodmeal acquisition and reproduction, and thereby dengue virus (DENV) transmission. It produces numerous immune factors, as well as immune-modulatory, vasodilatory, and anti-coagulant molecules that facilitate blood-feeding. To assess the impact of DENV infection on salivary gland physiology and function, we performed a comparative genome-wide microarray analysis of the naïve and DENV infection-responsive A. aegypti salivary gland transcriptomes. DENV infection resulted in the regulation of 147 transcripts that represented a variety of functional classes, including several that are essential for virus transmission, such as immunity, blood-feeding, and host-seeking. RNAi-mediated gene silencing of three DENV infection-responsive genes - a cathepsin B, a putative cystatin, and a hypothetical ankyrin repeat-containing protein - significantly modulated DENV replication in the salivary gland. Furthermore, silencing of two DENV infection-responsive odorant-binding protein genes (OBPs) resulted in an overall compromise in blood acquisition from a single host by increasing the time for initiation of probing and the probing time before a successful bloodmeal. We also show that DENV established an extensive infection in the mosquito's main olfactory organs, the antennae, which resulted in changes of the transcript abundance of key host-seeking genes. DENV infection, however, did not significantly impact probing initiation or probing times in our laboratory infection system. Here we show for the first time that the mosquito salivary gland mounts responses to suppress DENV which, in turn, modulates the expression of chemosensory-related genes that regulate feeding behavior. These reciprocal interactions may have the potential to affect DENV transmission between humans
Do hypoxia/normoxia culturing conditions change the neuroregulatory profile of Wharton Jelly mesenchymal stem cells secretome?
Introduction: The use of human umbilical cord Wharton Jelly-derived mesenchymal stem cells (hWJ-MSCs) has been considered a new potential source for future safe applications in regenerative medicine. Indeed, the application of hWJ-MSCs into different animal models of disease, including those from the central nervous system, has shown remarkable therapeutic benefits mostly associated with their secretome. Conventionally, hWJ-MSCs are cultured and characterized under normoxic conditions (21 % oxygen tension), although the oxygen levels within tissues are typically much lower (hypoxic) than these standard culture conditions. Therefore, oxygen tension represents an important environmental factor that may affect the performance of mesenchymal stem cells in vivo. However, the impact of hypoxic conditions on distinct mesenchymal stem cell characteristics, such as the secretome, still remains unclear. Methods: In the present study, we have examined the effects of normoxic (21 % O2) and hypoxic (5 % O2) conditions on the hWJ-MSC secretome. Subsequently, we address the impact of the distinct secretome in the neuronal cell survival and differentiation of human neural progenitor cells. Results: The present data indicate that the hWJ-MSC secretome collected from normoxic and hypoxic conditions displayed similar effects in supporting neuronal differentiation of human neural progenitor cells in vitro. However, proteomic analysis revealed that the use of hypoxic preconditioning led to the upregulation of several proteins within the hWJ-MSC secretome. Conclusions: Our results suggest that the optimization of parameters such as hypoxia may lead to the development of strategies that enhance the therapeutic effects of the secretome for future regenerative medicine studies and applications. © 2015 Teixeira et al.Portuguese Foundation for Science and Technology (FCT) (Ciência 2007
program and IF Development Grant (AJS); and pre-doctoral fellowships to
FGT (SFRH/69637/ 2010) and SIA (SFRH/BD/81495/2011); Canada Research
Chairs (LAB) and a SSE Postdoctoral Fellowship (KMP); The National Mass
Spectrometry Network (RNEM) (REDE/1506/REM/2005); co-funded by Programa
Operacional Regional do Norte (ON.2 – O Novo Norte), ao abrigo do Quadro de
Referência Estratégico Nacional (QREN), através do Fundo Europeu de
Desenvolvimento Regional (FEDER).info:eu-repo/semantics/publishedVersio
Early administration of abciximab reduces mortality in female patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention (from the EUROTRANSFER Registry)
Species delimitation and DNA barcoding of Atlantic Ensis (Bivalvia, Pharidae)
Ensis Schumacher, 1817 razor shells occur at both sides of the Atlantic and along the Pacific coasts of tropical west America, Peru, and Chile. Many of them are marketed in various regions. However, the absence of clear autapomorphies in the shell and the sympatric distributions of some species often prevent a correct identification of specimens. As a consequence, populations cannot be properly managed, and edible species are almost always mislabelled along the production chain. In this work, we studied whether the currently accepted Atlantic Ensis morphospecies are different evolutionary lineages, to clarify their taxonomic status and enable molecular identifications through DNA barcoding. For this, we studied 109 specimens sampled at 27 sites, which were identified as belonging to nine of those morphospecies. We analysed nucleotide variation at four nuclear (18S, 5.8S, ITS1, and ITS2) and two mitochondrial (COI and 16S) regions, although the 18S and 5.8S regions were not informative at the species level and were not further considered. The phylogenetic trees and networks obtained supported all morphospecies as separately evolving lineages. Phylogenetic trees recovered Ensis at each side of the Atlantic as reciprocally monophyletic. Remarkably, we confirm the co-occurrence of the morphologically similar E. minor (Chenu, 1843) and E. siliqua (Linné, 1758) along the NW Iberian coast, a fact that has been often overlooked. In South America, a relevant divergence between E. macha (Molina, 1792) individuals from Chile and Argentina was unveiled and suggests incipient speciation. We also confirm the occurrence of the North American species E. directus (Conrad, 1843) as far south as north-eastern Florida. Among the genomic regions analysed, we suggest COI as the most suitable DNA barcode for Atlantic Ensis. Our results will contribute to the conservation and management of Ensis populations and will enable reliable identifications of the edible species, even in the absence of the valves. The name Ensis coseli Vierna nom. nov. is proposed to replace E. minor Dall, 1899 non (Chenu, 1843)
Species delimitation and DNA barcoding of Atlantic Ensis (Bivalvia, Pharidae)
Ensis Schumacher, 1817 razor shells occur at both sides of the Atlantic and along the Pacific coasts of tropical west America, Peru, and Chile. Many of them are marketed in various regions. However, the absence of clear autapomorphies in the shell and the sympatric distributions of some species often prevent a correct identification of specimens. As a consequence, populations cannot be properly managed, and edible species are almost always mislabelled along the production chain. In this work, we studied whether the currently accepted Atlantic Ensis morphospecies are different evolutionary lineages, to clarify their taxonomic status and enable molecular identifications through DNA barcoding. For this, we studied 109 specimens sampled at 27 sites, which were identified as belonging to nine of those morphospecies. We analysed nucleotide variation at four nuclear (18S, 5.8S, ITS1, and ITS2) and two mitochondrial (COI and 16S) regions, although the 18S and 5.8S regions were not informative at the species level and were not further considered. The phylogenetic trees and networks obtained supported all morphospecies as separately evolving lineages. Phylogenetic trees recovered Ensis at each side of the Atlantic as reciprocally monophyletic. Remarkably, we confirm the co-occurrence of the morphologically similar E. minor (Chenu, 1843) and E. siliqua (Linné, 1758) along the NW Iberian coast, a fact that has been often overlooked. In South America, a relevant divergence between E. macha (Molina, 1792) individuals from Chile and Argentina was unveiled and suggests incipient speciation. We also confirm the occurrence of the North American species E. directus (Conrad, 1843) as far south as north-eastern Florida. Among the genomic regions analysed, we suggest COI as the most suitable DNA barcode for Atlantic Ensis. Our results will contribute to the conservation and management of Ensis populations and will enable reliable identifications of the edible species, even in the absence of the valves. The name Ensis coseli Vierna nom. nov. is proposed to replace E. minor Dall, 1899 non (Chenu, 1843)
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