1,166 research outputs found

    Porous Titanium surfaces to control bacteria growth: mechanical properties and sulfonated polyetheretherketone coating as antibiofounling approaches

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    Here, titanium porous substrates were fabricated by a space holder technique. The relationship between microstructural characteristics (pore equivalent diameter, mean free-path between pores, roughness and contact surface), mechanical properties (Young’s modulus, yield strength and dynamic micro-hardness) and bacterial behavior are discussed. The bacterial strains evaluated are often found on dental implants: Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. The colony-forming units increased with the size of the spacer for both types of studied strains. An antibiofouling synthetic coating based on a sulfonated polyetheretherketone polymer revealed an effective chemical surface modification for inhibiting MRSA adhesion and growth. These findings collectively suggest that porous titanium implants designed with a pore size of 100–200 µm can be considered most suitable, assuring the best biomechanical and bifunctional anti-bacterial properties.University of Seville VI Plan Propio de Investigación y Transferencia—US 2018, I.3A

    Balancing porosity and mechanical properties of titanium samples to favor cellular growth against bacteria

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    Two main problems limit the success of titanium implants: bacterial infection, which restricts their osseointegration capacity; and the stiffness mismatch between the implant and the host cortical bone, which promotes bone resorption and risk of fracture. Porosity incorporation may reduce this difference in stiffness but compromise biomechanical behavior. In this work, the relationship between the microstructure (content, size, and shape of pores) and the antibacterial and cellular behavior of samples fabricated by the space-holder technique (50 vol % NH4HCO3 and three ranges of particle sizes) is established. Results are discussed in terms of the best biomechanical properties and biofunctional activity balance (cell biocompatibility and antibacterial behavior). All substrates achieved suitable cell biocompatibility of premioblast and osteoblast in adhesion and proliferation processes. It is worth to highlighting that samples fabricated with the 100–200 μm space-holder present better mechanical behavior—in terms of stiffness, microhardness, and yield strength—which make them a very suitable material to replace cortical bone tissues. Those results exposed the relationship between the surface properties and the race of bacteria and mammalian cells for the surface with the aim to promote cellular growth over bacteria.University of Seville (Spain) VI Plan Propio de Investigación y Transferencia—US 2018, I.3A

    Stereoselective Synthesis of Iminosugar 2-Deoxy(thio)glycosides from Bicyclic Iminoglycal Carbamates Promoted by Cerium(IV) Ammonium Nitrate and Cooperative Brønsted Acid-Type Organocatalysis

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    The first examples of iminosugar-type 2-deoxy(thio)glycoside mimetics are reported. The key step is the activation of a bicyclic iminoglycal carbamate to generate a highly reactive acyliminium cation. Cerium(IV) ammonium nitrate efficiently promoted the formation of 2-deoxy S-glycosides in the presence of thiols, probably by in situ generation of catalytic HNO3, with complete α-stereoselectivity. Cooperative phosphoric acid/Schreiner's thiourea organocatalysis proved better suited for generating 2-deoxy O-glycosides, significantly broadening the scope of the approach.Ministerio de Economía y Competitividad SAF201676083-RMinisterio de Ciencia, Innovación y Universidades RTI2018-097609-B-C21European Cooperation in Science and Technology CA18132Consejo Europeo de Investigación ERC-COG: 64823

    A LoRaWAN testbed design for supporting critical situations: prototype and evaluation

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    The Internet of Things is one of the hottest topics in communications today, with current revenues of $151B, around 7 billion connected devices, and an unprecedented growth expected for next years. A massive number of sensors and actuators are expected to emerge, requiring new wireless technologies that can extend their battery life and can cover large areas. LoRaWAN is one of the most outstanding technologies which fulfill these demands, attracting the attention of both academia and industry. In this paper, the design of a LoRaWAN testbed to support critical situations, such as emergency scenarios or natural disasters, is proposed. This self-healing LoRaWAN network architecture will provide resilience when part of the equipment in the core network may become faulty. This resilience is achieved by virtualizing and properly orchestrating the different network entities. Different options have been designed and implemented as real prototypes. Based on our performance evaluation, we claim that the usage of microservice orchestration with several replicas of the LoRaWAN network entities and a load balancer produces an almost seamless recovery which makes it a proper solution to recover after a system crash caused by any catastrophic event.Postprint (published version

    Mortality attributable to extreme temperatures in Spain: A comparative analysis by city

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    BACKGROUND: The Low Temperature Days (LTD) have attracted far less attention than that of High Temperature Days (HTD), though its impact on mortality is at least comparable. This lower degree of attention may perhaps be due to the fact that its influence on mortality is less pronounced and longer-term, and that there are other concomitant infectious winters factors. In a climate-change scenario, the studies undertaken to date report differing results. The aim of this study was to analyse mortality attributable to both thermal extremes in Spain's 52 provinces across the period 2000-2009, and estimate the related economic cost to show the benefit or "profitability" of implementing prevention plans against LTD. METHODS: Previous studies enabled us: to obtain the maximum daily temperature above which HTD occurred and the minimum daily temperature below which LTD occurred in the 52 provincial capitals analysed across the same study period; and to calculate the relative and attributable risks (%) associated with daily mortality in each capital. These measures of association were then used to make different calculations to obtain the daily mean mortality attributable to both thermal extremes. To this end, we obtained a summary of the number of degrees whereby the temperature exceeded (excess °C) or fell short (deficit °C) of the threshold temperature for each capital, and calculated the respective number of extreme temperatures days. The economic estimates rated the prevention plans as being 68% effective. RESULTS: Over the period considered, the number of HTD (4373) was higher than the number of LTD (3006) for Spain as a whole. Notwithstanding this, in every provincial capital the mean daily mortality attributable to heat was lower (3deaths/day) than that attributable to cold (3.48deaths/day). In terms of the economic impact of the activation of prevention plans against LTD, these could be assumed to avoid 2.37 deaths on each LTD, which translated as a saving of €0.29M. Similarly, in the case of heat, 2.04 deaths could be assumed to be avoided each day on which the prevention plan against HTD was activated, amounting to a saving of €0.25M. While the economic cost of cold-related mortality across the ten-year period 2000-2009 was €871.7M, that attributable to heat could be put at €1093.2M. CONCLUSION: The effect of extreme temperatures on daily mortality was similar across the study period for Spain overall. The lower number of days with LTD meant, however, that daily cold-related mortality was higher than daily heat-related mortality, thereby making prevention plans against LTD more "profitable" prevention plans against HTD in terms of avoidable mortality.This study was supported by grants FIS ENPY 1001/13 & SEPY 1037/14 from Spain's Health Research Fund.S

    Application of age-length-keys to estimate catch-at-age for the North Atlantic albacore (Thunnus alalunga) stock

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    This document presents the results of applying two different methods to estimate catch-at-age for North Atlantic albacore (Thunnus alalunga). The Spanish albacore surface fishery size frequency data from 2003 to 2005 have been analyzed by means of MULTIFAN and age-lengthkeys (ALKs) have been derived from readings of sections obtained from sampled dorsal spiny rays of catch landed.Ce document présente les résultats de l’application de deux méthodes différentes visant à estimer la prise par âge pour le germon de l’Atlantique Nord (Thunnus alalunga). Les données de fréquences de tailles de la pêcherie de surface espagnole ciblant le germon de 2003 à 2005 ont été analysées à l’aide de MULTIFAN et des clefs âge-taille ont été calculées (ALKs) d’après la lecture des sections obtenues des rayons épineux de la dorsale échantillonnées de la prise débarquée.Este documento presenta los resultados de aplicar dos métodos distintos para estimar la captura por edad del atún blanco del Atlántico norte. La distribución por talla de las capturas comerciales de las flotas españolas de superficie fue analizada con MULTIFAN. Las claves talla edad fueron obtenidas por medio de la lectura de secciones de radios espinosos muestreados a partir de las capturas comerciales

    Molluscs collected with otter trawl in the northern Alboran Sea: main assemblages, spatial distribution and environmental linkage

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    Molluscan assemblages of circalittoral and bathyal soft bottoms of the northern Alboran Sea were studied using an experimental otter trawl. Samples of fauna were collected from 190 hauls during four MEDITS surveys carried out in spring between 2012 and 2015 at depths ranging from 30 to 800 m. Measurements of water column variables (temperature and salinity) and sediment samples were taken in the same locations where faunistic sampling was carried out. A total of 101 species grouped in 55 families were recorded. Cephalopods were the most abundant group, with Abralia veranyi dominating in abundance, Octopus vulgaris in biomass and Illex coindetii and Todarodes sagittatus being the most frequently collected species. Multivariate analyses carried out separately with abundance data of demersal species, benthic species, bivalves, gastropods and cephalopods as well as of all molluscs, generally resulted in three main molluscan assemblages corresponding to a shelf assemblage (30-200 m depth), an upper slope assemblage (201-350 m depth), and a middle slope assemblage (351-800 m depth). PERMANOVA test revealed that significant differences of different groups of molluscs in relation to depth were more acute than to geographical sectors of the Alboran Sea (eastern, central, eastern and insular sectors). Abundance, biomass and species richness decreased with depth with a clear dominance of cephalopods in the slope. Significant geographical differences were mainly detected for demersal and benthic species as well as for gastropods and cephalopods between the insular sector (Alboran Island) and the western and eastern continental sectors. Both depth and temperature were the most influencing variables in the different CCA analyses using datasets of molluscs with different life styles and from different classes, but sedimentological variables displayed a more acute significant relationship with the benthic molluscs than with the demersal ones

    Reliability and validity of the Severe Impairment Battery, short form (SIB-s), in patients with dementia in Spain

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    Las personas con demencia progresiva evolucionan hacia un estado donde los tests neuropsicológicos tradicionales dejan de ser eficaces. La batería de evaluación del deterioro grave, en su forma completa (SIB) y abreviada (SIB-s), se desarrolló para evaluar el estado cognitivo de pacientes con demencia avanzada. Objetivo. Evaluar los atributos psicométricos de la SIB-s en población española. Pacientes y métodos. Estudio transversal de 127 pacientes con demencia (86,6%, mujeres; edad media: 82,6 ± 7,5 años) evaluados con la SIB-s y las siguientes medidas: escala de deterioro global, miniexamen cognitivo (MEC), miniexamen del estado mental grave (sMMSE), índice de Barthel y escala del estado funcional. Resultados. La puntuación media total de la SIB-s fue de 19,1 ± 15,34 (rango: 0-48). Efectos suelo y techo < 20%. El análisis factorial identificó un único factor que explica el 68% de la varianza total de la escala. La consistencia interna fue alta (α de Cronbach: 0,96). La correlación ítem-total corregida osciló entre 0,27 y 0,83, y la homogeneidad de los ítems fue de 0,43. La fiabilidad test-retest e interevaluador fue satisfactoria (coeficiente de correlación intraclase: 0,96 y 0,95, respectivamente), así como la validez de constructo convergente con otras medidas cognitivas (MEC: 0,83; sMMSE: 0,9). La SIB-s mostró una correlación moderada con escalas cognitivas de dependencia funcional (índice de Barthel: 0,48; FAST: –0,74). El error estándar de la medida fue de 3,07 para el total de la escala. Conclusiones. La SIB-s es un instrumento fiable y válido, relativamente breve, para evaluar a pacientes con demencia avanzada en la población española.People with progressive dementia evolve into a state where traditional neuropsychological tests are not effective. Severe Impairment Battery (SIB) and short form (SIB-s) were developed for evaluating the cognitive status in patients with severe dementia. Aim. To evaluate the psychometric attributes of the SIB-s in patients with severe dementia. Patients and methods. 127 institutionalized patients (female: 86.6%; mean age: 82.6 ± 7.5 years-old) with dementia were assessed with the SIB-s, the Global Deterioration Scale (GDS), Mini-Mental State Examination (MMSE), Severe MiniMental State Examination (sMMSE), Barthel Index and FAST. Results. SIB-s acceptability, reliability, validity and precision were analyzed. The mean total score for scale was 19.1 ± 15.34 (range: 0-48). Floor effect was 18.1%, only marginally higher than the desirable 15%. Factor analysis identified a single factor explaining 68% of the total variance of the scale. Cronbach’s α coefficient was 0.96 and the item-total corrected correlation ranged from 0.27 to 0.83. The item homogeneity value was 0.43. Test-retest and inter-rater reliability for the total score was satisfactory (ICC: 0.96 and 0.95, respectively). The SIB-s showed moderate correlation with functional dependency scales (Barthel Index: 0.48, FAST: –0.74). Standard error of measurement was 3.07 for the total score. Conclusions. The SIB-s is a reliable and valid instrument for evaluating patients with severe dementia in the Spanish population of relatively brief instruments

    mu-Opioid inhibition of Ca2+ currents and secretion in isolated terminals of the neurohypophysis occurs via ryanodine-sensitive Ca2+ stores

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    mu-Opioid agonists have no effect on calcium currents (I(Ca)) in neurohypophysial terminals when recorded using the classic whole-cell patch-clamp configuration. However, mu-opioid receptor (MOR)-mediated inhibition of I(Ca) is reliably demonstrated using the perforated-patch configuration. This suggests that the MOR-signaling pathway is sensitive to intraterminal dialysis and is therefore mediated by a readily diffusible second messenger. Using the perforated patch-clamp technique and ratio-calcium-imaging methods, we describe a diffusible second messenger pathway stimulated by the MOR that inhibits voltage-gated calcium channels in isolated terminals from the rat neurohypophysis (NH). Our results show a rise in basal intracellular calcium ([Ca(2+)]i) in response to application of [D-Ala(2)-N-Me-Phe(4),Gly5-ol]-Enkephalin (DAMGO), a MOR agonist, that is blocked by D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP), a MOR antagonist. Buffering DAMGO-induced changes in [Ca(2+)]i with BAPTA-AM completely blocked the inhibition of both I(Ca) and high-K(+)-induced rises in [Ca(2+)]i due to MOR activation, but had no effect on kappa-opioid receptor (KOR)-mediated inhibition. Given the presence of ryanodine-sensitive stores in isolated terminals, we tested 8-bromo-cyclic adenosine diphosphate ribose (8Br-cADPr), a competitive inhibitor of cyclic ADP-ribose (cADPr) signaling that partially relieves DAMGO inhibition of I(Ca) and completely relieves MOR-mediated inhibition of high-K(+)-induced and DAMGO-induced rises in [Ca(2+)]i. Furthermore, antagonist concentrations of ryanodine completely blocked MOR-induced increases in [Ca(2+)]i and inhibition of I(Ca) and high-K(+)-induced rises in [Ca(2+)]i while not affecting KOR-mediated inhibition. Antagonist concentrations of ryanodine also blocked MOR-mediated inhibition of electrically-evoked increases in capacitance. These results strongly suggest that a key diffusible second messenger mediating the MOR-signaling pathway in NH terminals is [Ca(2+)]i released by cADPr from ryanodine-sensitive stores
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