249 research outputs found
Enhanced quench propagation in 2G-HTS coils co-wound with stainless steel or anodised aluminium tapes
Early quench detection and thermal stability of superconducting coils are of great relevance for practical applications. Magnets made with second generation high temperature superconducting (2G-HTS) tapes present low quench propagation velocities and therefore slow voltage development and high local temperature rises, which may cause irreversible damage. Since quench propagation depends on the anisotropy of the thermal conductivity, this may be used to achieve an improvement of the thermal stability and robustness of 2G-HTS coils. On pancake type coils, the thermal conductivity along the tapes (coil's azimuthal direction) is mostly fixed by the 2G-HTS tape characteristics, so that the reduction of anisotropy relies on the improvement of the radial thermal conductivity, which depends on the used materials between superconducting tapes, as well as on the winding and impregnation processes. In this contribution, we have explored two possibilities for such anisotropy reduction: by using anodised aluminium or stainless steel tapes co-wound with the 2G-HTS tapes. For all the analysed coils, critical current distribution, minimum quench energy values and both tangential and radial quench propagation velocities at different temperatures and currents are reported and compared with the results of similar coils co-wound with polyimide (Kapton®) tapes.This work was supported by the Spanish Ministerio de EconomÃa y Competitividad and the European FEDER Program (Projects MAT2011-22719 and ENE-2014-52105-R), and by the Gobierno de Aragón (research group T12).Peer reviewe
Electromagnetic behaviour and thermal stability of a conduction-cooled, no-insulated 2G-HTS coil at intermediate temperatures
The electromagnetic and thermal properties of a double pancake coil made of second generation high temperature superconductor, 2G-HTS, have been studied. The coil was wound with no-insulation between turns (NI coil) and was later impregnated with epoxy resin and glued to a copper support plate. The coil was thermally anchored to the cryocooler cold finger and cooled by conduction. After several thermal cycles no degradation of its superconducting properties was observed. The coil was operated under high vacuum and high currents (up to 400 A in steady conditions) at different temperatures in the range between 5 K and 77 K, with special focus on the analysis above 30 K. The charge and discharge characteristics, and the experimentally measured and numerically estimated critical currents, have been studied. The different loss contributions during current ramp and the thermal contact conductance between different parts of the double pancake coil have been measured. The implications of these two factors on the thermal stability and the behaviour of the whole cryogenic system are discussed
A new species of Liolaemus related to L. nigroviridis from the Andean highlands of Central Chile (Iguania, Liolaemidae)
Indexación: Web of Science; Scopus.The Liolaemus nigroviridis group is a clade of highland lizards endemic to Chile. These species are distributed from northern to central Chile, and currently there are no cases of sympatric distribution. This study describes a new species, Liolaemus uniformis sp. n., from this group, and provides a detailed morphological characterization and mitochondrial phylogeny using cytochrome-b. Liolaemus uniformis was found in sympatry with L. nigroviridis but noticeably differed in size, scalation, and markedly in the color pattern, without sexual dichromatism. This new species has probably been confused with L. monticola and L. bellii, both of which do not belong to the nigroviridis group. The taxonomic issues of this group that remain uncertain are also discussed.https://zookeys.pensoft.net/articles.php?id=601
Colapso gravitacional radiativo esféricamente simétrico en relatividad general: introducción del factor de flujo, el factor de Eddington y la influencia de la relación de clausura entre ellos sobre la evolución del sistema
The H–J–Rs’ method [Phys. Rev. D22, 2305 (1980)] is extended to include the Eddington’s variable factor, the radiation flux factor and a closure relationship between them in order to show its influence on the behavior of density, pressure, fluid velocity and energy radiation flux, among others, of an object under gravitational collapse within the framework of general relativity. The post-quasistatic approximation of Herrera et al [Phys. Rev. D65, 104004 (2002)] along with the Tolman VI equation of state and the Lorentz–Eddington, Bowers–Wilson and Maximum Packing relationships were used to find that the choice of different closure relationships does not affect the global behavior of the system but only the instantaneous values of the different physical quantities.
Se extiende el método H–J–R [Phys. Rev. D22, 2305 (1980)] utilizando el factor variable de Eddington y el factor de flujo de radiación, y se presenta la influencia de la elección de la relación entre ellos sobre el comportamiento en el tiempo de la densidad, presión, velocidad del fluido y flujo de radiación, entre otras, de un objeto en fase de colapso gravitacional radiativo en el marco de la relatividad general. Para tal fin, se ha utilizado la aproximación poscuasiestática de Herrera et al [Phys. Rev. D65, 104004 (2002)] con la ecuación de estado Tolman VI y las relaciones de clausura de Lorentz–Eddington, Bowers–Wilson y Maximum Packing, encontrando que la elección de una relación de clausura particular no afecta el comportamiento General del colapso, pero sà afecta los valores instantáneos de las diferentes magnitudes fÃsicas.
 
Modulation of VEGF-induced migration and network formation by lymphatic endothelial cells:Roles of platelets and podoplanin
Lymphatic endothelial cells (LEC) express the transmembrane receptor podoplanin whose only known endogenous ligand CLEC-2 is found on platelets. Both podoplanin and CLEC-2 are required for normal lymphangiogenesis as mice lacking either protein develop a blood-lymphatic mixing phenotype. We investigated the roles of podoplanin and its interaction with platelets in migration and tube formation by LEC. Addition of platelets or antibody-mediated crosslinking of podoplanin inhibited LEC migration induced by vascular endothelial growth factors (VEGF-A or VEGF-C), but did not modify basal migration or the response to basic fibroblast growth factor or epidermal growth factor. In addition, platelets and podoplanin crosslinking disrupted networks of LEC formed in co-culture with fibroblasts. Depletion of podoplanin in LEC using siRNA negated the pro-migratory effect of VEGF-A and VEGF-C. Inhibition of RhoA or Rho-kinase reduced LEC migration induced by VEGF-C, but had no further effect after crosslinking of podoplanin, suggesting that podoplanin is required for signaling downstream of VEGF-receptors but upstream of RhoA. Together, these data reveal for the first time that podoplanin is an intrinsic specific regulator of VEGF-mediated migration and network formation in LEC and identify crosslinking of podoplanin by platelets or antibodies as mechanisms to modulate this pathway
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CLEC-2 and Syk in the megakaryocytic/platelet lineage are essential for development
The C-type lectin receptor CLEC-2 signals through a pathway that is critically dependent on the tyrosine kinase Syk. We show that homozygous loss of either protein results in defects in brain vascular and lymphatic development, lung inflation and perinatal lethality. Furthermore, we find that conditional deletion of Syk in the haematopoietic lineage, or conditional deletion of CLEC-2 or Syk in the megakaryocyte/platelet lineage, also causes defects in brain vascular and lymphatic development, although the mice are viable. In contrast, conditional deletion of Syk in other haematopoietic lineages had no effect on viability or brain vasculature and lymphatic development. We show that platelets, but not platelet releasate, modulate the migration and intercellular adhesion of lymphatic endothelial cells through a pathway that is dependent on CLEC-2 and Syk. These studies demonstrate that megakaryocyte/platelet expression of CLEC-2 and Syk is required for normal brain vasculature and lymphatic development and that platelet CLEC-2 and Syk directly modulate lymphatic endothelial cell behaviour in vitro
The methodology of surveillance for antimicrobial resistance and healthcare-associated infections in Europe (SUSPIRE): a systematic review of publicly available information.
OBJECTIVES: Surveillance is a key component of any control strategy for healthcare-associated infections (HAIs) and antimicrobial resistance (AMR), and public availability of methodologic aspects is crucial for the interpretation of the data. We sought to systematically review publicly available information for HAIs and/or AMR surveillance systems organized by public institutions or scientific societies in European countries. METHODS: A systematic review of scientific and grey literature following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines was performed. Information on HAIs and/or AMR surveillance systems published until 31 October 2016 were included. RESULTS: A total of 112 surveillance systems were detected; 56 from 20 countries were finally included. Most exclusions were due to lack of publicly available information. Regarding AMR, the most frequent indicator was the proportion of resistant isolates (27 of 34 providing information, 79.42%); only 18 (52.9%) included incidence rates; the data were only laboratory based in 33 (78.5%) of the 42 providing this information. Regarding HAIs in intensive care units, all 22 of the systems providing data included central line-associated bloodstream infections, and 19 (86.3%) included ventilator-associated pneumonia and catheter-associated urinary tract infections; incidence density was the most frequent indicator. Regarding surgical site infections, the most frequent procedures included were hip prosthesis, colon surgery and caesarean section (21/22, 95.5%). CONCLUSIONS: Publicly available information about the methods and indicators of the surveillance system is frequently lacking. Despite the efforts of European Centre for Disease Control and Prevention (ECDC) and other organizations, wide heterogeneity in procedures and indicators still exists
El estudio PROPRESE: resultados de un nuevo modelo organizativo en atención primaria para pacientes con cardiopatÃa isquémica crónica basado en una intervención multifactorial
ResumenObjetivoComparando los resultados obtenidos en los estudios EUROASPIRE I y EUROASPIRE III en pacientes con cardiopatÃa isquémica se muestra que el grado de control de los factores de riesgo mayores es mejorable. El objetivo de este estudio es evaluar la eficacia de una intervención multifactorial orientada a la mejora del grado de control en estos pacientes en el ámbito de la atención primaria.MétodosEn este estudio de intervención aleatorizado, con 1 año de seguimiento, se reclutó a pacientes con diagnóstico de cardiopatÃa isquémica (145 en el grupo de intervención y 1.461 en el grupo control). Se aplicó una intervención organizativa mixta basada en la mejora de la relación profesional sanitario-paciente (de acuerdo a los modelos del Chronic Care, el Stanford Expert Patient Programme y el Kaiser Permanente) y en la formación profesional continuada. Los principales resultados fueron el efecto sobre el tabaquismo, el colesterol unido a lipoproteÃnas de baja densidad (cLDL), la presión arterial sistólica (PAS) y la presión arterial diastólica (PAD) a través de un análisis multivariable.ResultadosLas caracterÃsticas de los pacientes fueron: edad (68,4±11,8 años), varones (71,6%), diabetes mellitus (51,3%), dislipemia (68,5%), hipertensión arterial (76,7%), no fumadores (76,1%); cLDL < 100mg/dl (46,9%); PAS < 140mmHg (64,5%); PAD < 90 (91,2%). El análisis multivariable mostró que el riesgo para el buen control en el grupo de intervención fue tabaquismo, riesgo relativo ajustado (RRa): 15,7 (intervalo de confianza del 95% [IC95%], 4,2–58,7); p < 0,001; cLDL, RRa: 2,98 (IC95%, 1,48–6,02); p < 0,002; PAS, RRa: 1.97 (IC95%, 1,21–3,23); p < 0,007, y PAD; RRa: 1,51 (IC95%, 0,65–3,50); p < 0,342.ConclusionesUna intervención multifactorial basada en el modelo de paciente crónico centrada en atención primaria y que facilite la toma de decisiones compartidas con los pacientes y la formación de los profesionales mejora el grado de control de los factores de riesgo cardiovascular (tabaquismo, cLDL y PAS). Las estrategias de mejora en la atención de la cronicidad pueden ser una herramienta eficaz para conseguir mejores resultados.AbstractObjectiveComparison of the results from the EUROASPIRE I to the EUROASPIRE III, in patients with coronary heart disease, shows that the prevalence of uncontrolled risk factors remains high. The aim of the study was to evaluate the effectiveness of a new multifactorial intervention in order to improve health care for chronic coronary heart disease patients in primary care.MethodsIn this randomized clinical trial with a 1-year follow-up period, we recruited patients with a diagnosis of coronary heart disease (145 for the intervention group and 1461 for the control group). An organizational intervention on the patient-professional relationship (centered on the Chronic Care Model, the Stanford Expert Patient Programme and the Kaiser Permanente model) and formative strategy for professionals were carried out. The main outcomes were smoking control, low-density lipoprotein cholesterol (LDL-C), systolic blood pressure (SBP) and diastolic blood pressure (DBP). A multivariate analysis was performed.ResultsThe characteristics of patients were: age (68.4±11.8 years), male (71.6%), having diabetes mellitus (51.3%), dyslipidemia (68.5%), arterial hypertension (76.7%), non-smokers (76.1%); LDL-C < 100mg/dL (46.9%); SBP < 140mmHg (64.5%); DBP < 90 (91.2%). The multivariable analysis showed the risk of good control for intervention group to be: smoking, adjusted relative risk (aRR): 15.70 (95% confidence interval [95%CI], 4.2–58.7); P < .001; LDL-C, aRR: 2.98 (95%CI, 1.48–6.02); P < .002; SPB, aRR: 1.97 (95%CI, 1.21–3.23); P < .007, and DBP: aRR: 1.51 (95%CI, 0.65–3.50); P < .342.ConclusionsAn intervention based on models for chronic patients focused in primary care and involving patients in medical decision making improves cardiovascular risk factors control (smoking, LDL-C and SBP). Chronic care strategies may be an efficacy tool to help clinicians to involve the patients with a diagnosis of CHD to reach better outcomes
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