Differences in reactivity of oxide growth during the oxidation of Zircaloy-4 in water vapour before and after the kinetic transition

International audienceThe oxidation of Zircaloy-4 by water vapour has been studied between 500 and 550 °C, the water vapour partial pressure ranging in 13-80 hPa, using isothermal and isobaric thermogravimetry, and calorimetry. During gravimetry experiments, sudden changes in temperature or water vapour pressure have also been performed. It results that the approximations of steady state and rate-limiting step are only valid before the kinetic transition. In the post-transition region, a significant influence of water vapour and hydrogen partial pressures has been found, contrarily to the kinetic behaviour before the transition (which is in this last case, in good agreement with a rate-limiting step of diffusion of oxygen vacancies). It comes out that the post-transition kinetic behaviour is definitely not the same as before the transition

Kinetic study of the oxidation by water vapour of a zirconium based alloy: Recrystallised Zircaloy-4

International audienceThe oxidation of a zirconium based alloy (recrystallised Zircaloy-4) has been studied at 500°C, by thermogravimetry under controlled partial pressures of water vapour and hydrogen. The study is restricted to the pre-transition state of oxidation, the aim being to identify the rate-limiting step of the oxide growth. It has been verified experimentally that the system is in a steady state during the pre-transition period. Moreover, using a method based on the isolation method, it has been shown that the oxidation could be described by a single rate-limiting step only when a weight gain of 7.5 mg.dm-2 has been reached. Since the kinetic curves are not parabolic, a diffusion model has been proposed, which takes into account the effect of barriers on the diffusion (such as pores, blisters, cracks... in the oxide layer) and which is in good agreement with the experimental curves. Then, numerical fitting has shown that the beginning of the oxidation could be interpreted by a mixed reaction-diffusion steady solution, which tends towards a single diffusion rate-limiting step when the oxide layer is thick enough (about 0.5 m)

Microwave sintering of dense and lattice 3Y-TZP samples shaped by digital light processing

Nowadays it is possible to produce ceramic parts with solid and complex shapes with rapid and efficient shaping and sintering techniques. In this paper, 3mol% yttria stabilized zirconia (3Y-TZP) dense and lattice parts were shaped by Digital light processing method (DLP) and densified by conventional (CV) and microwave (MW) sintering. 3Y-TZP samples were MW sintered up to 1550 °C with different heating rates (10, 30, and 50 °C/min) for the dense samples and 30 °C/min for the lattice samples. Controlled thermal cycles with a homogenous heating and no thermal runaway was reached. CV sintering was carried out at 10 °C/min up to 1550 °C. No inter-layer delamination was detected after sintering by the two methods. Both dense and lattice MW-sintered samples reached high final densities (equivalent to obtained values with CV-sintered samples, i.e., ≥98% T.D.), but exhibited a lower average grain size than CV-sintered materials. The different architectures between dense and lattice samples resulted in a different specific absorbed power: the power absorbed by the dense sample is lower than that absorbed by the lattice one meaning that this sample architecture heats up easily

Role of surface microgeometries on electron escape probability and secondary electron yield of metal surfaces

The influence of microgeometries on the Secondary Electron Yield (SEY) of surfaces is investigated. Laser written structures of different aspect ratio (height to width) on a copper surface tuned the SEY of the surface and reduced its value to less than unity. The aspect ratio of microstructures was methodically controlled by varying the laser parameters. The results obtained corroborate a recent theoretical model of SEY reduction as a function of the aspect ratio of microstructures. Nanostructures - which are formed inside the microstructures during the interaction with the laser beam - provided further reduction in SEY comparable to that obtained in the simulation of structures which were coated with an absorptive layer suppressing secondary electron emission

Smart Nanoparticles as Advanced Anti-Akt Kinase Delivery Systems for Pancreatic Cancer Therapy

Pancreatic cancer is one of the deadliest cancers partly due to late diagnosis, poor drug delivery to the target site, and acquired resistance to therapy. Therefore, more effective therapies are urgently needed to improve the outcome of patients. In this work, we have tested self-assembling genetically engineered polymeric nanoparticles formed by elastin-like recombinamers (ELRs), carrying a small peptide inhibitor of the protein kinase Akt, in both PANC-1 and patient-derived pancreatic cancer cells (PDX models). Nanoparticle cell uptake was measured by flow cytometry, and subcellular localization was determined by confocal microscopy, which showed a lysosomal localization of these nanoparticles. Furthermore, metabolic activity and cell viability were significantly reduced after incubation with nanoparticles carrying the Akt inhibitor in a time- and dose-dependent fashion. Self-assembling 73 ± 3.2 nm size nanoparticles inhibited phosphorylation and consequent activation of Akt protein, blocked the NF-κB signaling pathway, and triggered caspase 3-mediated apoptosis. Furthermore, in vivo assays showed that ELR-based nanoparticles were suitable devices for drug delivery purposes with long circulating time and minimum toxicity. Hence, the use of these smart nanoparticles could lead to the development of more effective treatment options for pancreatic cancer based on the inhibition of Akt

Ectoparasites of Coragyps atratus (Bechstein, 1793) (Accipitriformes: Cathartidae) on Bucaramanga, Santander, Colombia

Identificar y conformar una lista de especies de ectoparásitos en el gallinazo negro en dos localidades de la ciudad de Bucaramanga, Colombia. Alcance. Realizar un aporte al conocimiento sobre las especies de ectoparásitos encontrados en piel y plumaje del gallinazo negro en el área metropolitana de Bucaramanga, en el nororiente de los Andes. Metodología. Las aves fueron capturadas en la Plaza de Mercado Guarín y en el Centro de Disposición de Residuos Sólidos “El Carrasco”, ambos en el área metropolitana de Bucaramanga, Colombia. Para obtener los ectoparásitos, los gallinazos se introdujeron uno por uno, en una cámara de fumigación previamente modificada para preservar la vida del ave durante el procedimiento. Adicionalmente, se tomaron algunas plumas y se preservaron en etanol 70%. Principales resultados. Se colectaron 1.696 ectoparásitos sobre 18 gallinazos negros (Coragyps atratus) en dos sitios de Bucaramanga (Colombia). Los parásitos fueron identificados como Cathartacarus coragyps (Gabuciniidae), Dermanysus gallinae (Dermanyssidae), Cuculiphilus alternatus (Menoponidae), Falcolipeurus marginalis (Philopteridae), Laemobothrion glutinans (Laemobothriidae) y Olfesia bisulcata (Hippoboscidae). Las especies más abundantes fueron Cuculiphilus alternatus con 1.217 individuos y Cathartacarus coragyps con 295. Conclusiones. La mayor parte de estos registros son nuevos para la región y amplían el conocimiento con respecto a la distribución de estos ectoparásitos. Tanto las pruebas de Mann-Whitney como los índices parasitológicos calculados permiten observar diferencias entre los dos sitios de muestreo.To identify and to list ectoparasite species of black vulture in two locations in Bucaramanga, Colombia. Scope. To contribute to the knowledge of ectoparasites species found in black vultures in the metropolitan area of Bucaramanga, at the northeastern Andes. Methodology. The birds were captured in Guarin Marketplace and "El Carrasco" Solid Waste Disposal Center, both in the metropolitan area of Bucaramanga, Colombia. To obtain the ectoparasites, each black vulture were introduced into a fumigation chamber previously modified to preserve the life of the bird during the procedure. Moreover, some feathers were taken and preserved in ethanol 70%. Main results. In total, 1,696 ectoparasites were collected from 18 black vultures (Coragyps atratus) in two localities of Bucaramanga (Colombia). The parasites were identified as Cathartacarus coragyps (Gabuciniidae), Dermanysus gallinae (Dermanyssidae), Cuculiphilus alternatus (Menoponidae), Falcolipeurus marginalis (Philopteridae), Laemobothrion glutinans (Laemobothriidae) and Olfesia bisulcata (Hippoboscidae). The most abundant species were Cuculiphilus alternatus with 1,217 specimens and Cathartacarus coragyps with 295. Conclusions. Most of these records are new to the region and contribute to improving the knowledge concerning the ectoparasites distribution in the study area. Mann-Whitney tests and the calculated parasitological indexes show differences between the two sampling places

The influence of air‐sea coupling on forecasts of the 2016 Indian summer monsoon and its intraseasonal variability

Daily initialized coupled and uncoupled numerical weather prediction (NWP) forecasts from the global Met Office Unified Model (MetUM) are compared for the 2016 Indian summer monsoon. Three MetUM configurations are used: atmosphere‐only (ATM), coupled to a mixed‐layer ocean model (KPP), and coupled to a dynamical ocean model (NEMO). The analysis focuses on the impact of air‐sea coupling, particularly in the Bay of Bengal (BoB), on NWP for monsoon rainfall. Seasonal‐mean biases in all three configurations are highly consistent and driven by errors in atmospheric processes. Rainfall is initially overestimated over India, but underestimated over the BoB, the latter associated with too much shortwave radiation and too little cloud cover in MetUM. The excess shortwave radiation (>40 Wm‐2 over the northwest BoB) is partially compensated by additional latent cooling, primarily due to overestimated surface wind speeds. In NEMO and KPP, coupling improves the timing of intraseasonal active and break phases over India, primarily the end of these phases, which are systematically too late in ATM. NEMO and KPP show a more realistic intraseasonal local phase relationship between sea surface temperature (SST) and rainfall throughout the BoB, but no configuration reproduces the observed significant lagged relationship between BoB SST and Indian rainfall. The lack of this relationship may be partly attributed to weak heat flux feedbacks to northern BoB SST, with the forecast shortwave feedback having systematically the wrong sign (positive) compared to satellite radiation, and thus contributing to SST warming at all lead times. Based on these MetUM forecasts, there is a limited impact of coupling on NWP for monsoon rainfall, both for the mean rainfall and intraseasonal variability. Further research to improve NWP for monsoon rainfall should focus on reducing MetUM atmospheric systematical biases

Trombolisis en el tromboembolismo de pulmón

Fil: Valdivieso, W.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área de CardiologíaFil: Gambarte, A.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área de CardiologíaFil: Piasentín, J.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área de CardiologíaFil: Limia, P.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Área de Cardiologí

Evaluation of the prognostic value of the risk, injury, failure, loss and end-stage renal failure (RIFLE) criteria for acute kidney injury

AIM: The experts have argued about the use of the risk, injury, failure, loss and end-stage renal failure (RIFLE) criteria as a prognosis scoring system. We examined the association between in-hospital mortality and the RIFLE criteria, and discussed its accuracy as a prognosis factor. METHODS: In this prospective study, we analysed the data gathered from a cohort of 956 patients admitted in a Spanish tertiary hospital between January 1998 and April 2006. Hazard ratios for mortality, and survival curves within 60 days were calculated. Discrimination and calibration of the model were also assessed. RESULTS: Excluding 53 patients, 903 patients were finally analysed. We classified them into groups according to the maximum RIFLE class reached during their admission. The RIFLE class was assessed by the glomerular filtration rate criterion. We found an increase in the in-hospital mortality risk. Cox proportional hazard models showed that RIFLE classes risk, injury, and failure were significant predictive factors (hazard ratios were 2.77, 3.23 and 3.52, respectively; P for trend was 0.005). The multivariate analyses from the cross-classification of the participants according to Liano score values (severity of illness) and RIFLE classes showed additive effects of the exposures on in-hospital mortality. CONCLUSION: In this population, the risk of in-hospital mortality during the acute kidney injury (AKI) episode was positively associated with RIFLE classes. We showed that the RIFLE classification system had discriminative power in predicting hospital mortality within 60 days in AKI patients, but not better than a specific AKI predictive model. However, a combined use of both may give a more robust prognosis system

Understanding Individual Differences for Tailored Smoking Cessation Apps

Finding ways to help people quit smoking is a high priority in health behavior change research. Recent HCI studies involving technologies using specific quitting techniques such as social support and SMS messaging to help people quit have reported some success. Early studies using computer generated print material report significant success of tailored versus non-tailored material, however, there is limited understanding on what aspects of digitally delivered quitting assistance should be tailored and how. To address this, we have conducted an empirical investigation with smokers to identify perceived importance of different types of help when quitting and the potential role of technology in providing such help. We found that people are highly individual in their approach to quitting and the kind of help they regard as relevant to their situation. Our contribution is a collection of empirically derived themes for tailoring smoking cessation apps to individual quitting needs. Author Keywords Smoking cessation; tailoring; individual differences; healt