2,170 research outputs found
The chaos of hypertension guidelines for chronic kidney disease patients
Three major guidelines deal with blood pressure thresholds and targets for antihypertensive drug therapy in chronic kidney disease (CKD) patients: the 2012 Kidney Disease: Improving Global Outcomes Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease; the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults; and the 2018 ESC/ESH Guidelines for the Management of Arterial Hypertension. However, a careful reading of the three guidelines leaves the practicing physician confused about the definition of CKD, how hypertension and secondary hypertension should be diagnosed in CKD patients and what the blood pressure thresholds, targets and compelling indications of antihypertensive drug therapy should be for this population. Current guidelines refer to different CKD populations and propose different definitions of hypertension, different thresholds to initiate antihypertensive therapy in CKD patients and different BP targets compelling antihypertensive drug use. The different bodies producing guidelines should work together towards a unified definition of CKD, a unified concept of hypertension and unified BP thresholds and targets for hypertensive drug therapy for CKD patients. Otherwise they risk promoting confusion and therapeutic nihilism among physicians and patientsResearch by the authors was supported by FIS CP14/00133, PI16/02057, PI18/01366, PI19/00588, PI19/00815, DTS18/00032, ERA-PerMed-JTC2018 (KIDNEY ATTACK AC18/00064 and PERSTIGAN AC18/00071), ISCIII-RETIC REDinREN RD016/0009 Fondos FEDER, FRIAT, Sociedad Española de Nefrología, Comunidad de Madrid B2017/BMD-3686 CIFRA2-C
Tribological behaviour of the low and high viscosity peek at various testing scales
Polyetheretherketone (PEEK) has become most attractive as a sliding bearing material in industrial applications, due to its excellent thermal stability, good friction and wear resistance. These properties promote the material to be used in so called high performance tribological applications. However, fundamental mechanisms governing friction and wear are not yet fully understood and neither is the influence of composition parameters. An important parameter is PEEK’s viscosity during injection moulding which is heated up to semi-solid state, between its glass transition and melting temperature. It is not known to what extent the injection viscosity, related to the applied temperature profile, affects subsequent tribological features. This paper studies the friction and wear performance of low and high viscosity PEEK under dry reciprocating sliding contact. The tests were performed with small and large scale specimens under pin-on-plate and flat-on-flat configuration, respectively; to determine the transitions in tribological behaviour at different scales and to identify the applications limits. Tests were carried out at controlled atmosphere with 25 °C and a relative humidity of 50%. Parameters such as contact pressures and sliding speed were limited at 10 MPa and 20 mm/s, respectively; post mortem analyses were carried out by means of 2-D surface topography and optical microscopy. The results show that PEEK injected at high viscosity exhibits a tribological performance with a relatively high coefficient of friction and high wear rate compare to PEEK injected at low viscosity
An improved model for fast and reliable harbour wave agitation assessment
ABSTRACT: This study presents the new advances achieved in the field of harbour agitation climate assessment. Based on the improvement of an elliptic mild-slope model (MSP), which realistically reconstructs waves inside any-sized basin, represented by high-detailed unstructured meshes, and forced by real-shaped outer spectral data. A new solver is proposed for high performance runs, which allow fast agitation hindcast for statistical downtime analysis within an iterative and multi-scenario approach. Also, a realistic assimilation of partial reflection processes in quays/docks/wharfs/breakwaters is proposed. The model has been successfully validated in several harbours of special relevance in Spain with in situ measurements, through the assimilation of the hybrid downscaling (Camus et al., 2011) technique combined with monochromatic-based wave spectral reconstruction.This work has been also partially funded under the RETOS program of the Spanish Ministry of Science, Innovation and Universities (BIA2017-87213-R). We would like to thank Puertos del Estado of Spain for providing spectral outer wave spectral forcing and wave agitation measurements, for gather/organize each Port Authority base data required
Gastrointestinal Parasites of Owl Monkeys ( Aotus Azarai Azarai ) in the Argentinean Chaco
In fragmented habitats, an increase in the proportion of available forest edge has been positively correlated to parasite richness. We evaluated how the presence of forest edge may affect parasite-host dynamics in a population of wild owl monkeys (Aotus azarai azarai) in an unlogged gallery forest in Formosa, Argentina. We collected 53 fecal samples from groups inhabiting edge territories (n = 7 groups, 33 samples) and groups inhabiting the interior of the forest (n = 3 groups, 15 samples). We compared the number of parasite species (richness) found between the two types of groups, as well as the frequency of samples with multiple infections (more than one parasite species in the sample) and the distribution of helminths on the forest floor between habitat types. The number of parasite species, the proportion of samples with multiple infections and the helminth distribution were not significantly different across the two habitat types.En hábitats fragmentados, un incremento en la proporción de borde de bosque ha sido correlacionado con la riqueza de parásitos. Evaluamos cómo la presencia de borde de bosque puede afectar la dinámica de parasite-hospedero en una población silvestre de monos de noche (Aotus azarai azarai) en un bosque de galería no perturbado en Formosa, Argentina. Colectamos 53 muestras de heces fecales de grupos que habitaban territorios en el borde del bosque (n=7 grupos, 33 muestras) y grupos habitando al interior del bosque (n=3 grupos, 15 muestras). Comparamos el número de especies de parásitos (riqueza) encontrado entre los dos tipos de grupos, así como la frecuencia de muestras con múltiples infecciones (más de una especie de parásito en la muestra) y la distribución de helmintos en le suelo del bosque entre tipos de hábitat. El número de especies de parásitos, la proporción de muestras con múltiples infecciones y la distribución de helmintos no fue significativamente diferente entre los dos tipos de hábitat.Fil: Perea Rodriguez, J. P.. Florida International University; Estados Unidos. DuMond Conservancy; Estados UnidosFil: Milano, Alicia María Francisca. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio Biología de los Parásitos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oscherov, Elena Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología. Laboratorio Biología de los Parásitos; ArgentinaFil: Fernandez Duque, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin
Meta-analysis: diagnostic accuracy of hepatitis C core antigen detection during therapy with direct-acting antivirals
Background: Treatment of hepatitis C virus (HCV) infection with direct-acting antivirals (DAAs) is monitored by assessing plasma HCV-RNA load. However, detection of HCV core antigen (HCVcAg) may be an alternative. Aim: To evaluate the diagnostic performance of the HCVcAg assay to monitor the efficacy of DAAs in HCV-infected patients METHODS: We performed searches in multiple electronic databases until 6 July 2022, of studies evaluating the HCVcAg detection in plasma or serum compared with the HCV-RNA test (gold standard). We calculated pooled measurement at 2 and 4 weeks of treatment, and at end-of-treatment (EOT), as well as sustained virological response (SVR; 12 weeks after EOT). Results: We selected 16 studies from 2016 to 2022, with 3237 patients and 8958 samples. Overall, the diagnostic performance and clinical utility of the HCVcAg assay were poor at week 2 (sensitivity = 0.40, specificity = 0.96, positive likelihood ratio (PLR) = 9.16, negative likelihood ratio (NLR) = 0.63, and area under the summary receiver operating curve (SROC) = 0.57), fair at week 4 (sensitivity = 0.30, specificity = 0.90, PLR = 3.18, NLR = 0.77, and AUC = 0.79), acceptable at EOT (sensitivity = 0.40, specificity =0.98, PLR = 16.54, NLR = 0.62, and AUC = 0.97) and excellent for SVR (sensitivity = 0.94, specificity = 0.99, PLR = 107.54, NLR = 0.06, and AUC = 0.99). Conclusions: The HCVcAg assay may be helpful for monitoring the efficacy of HCV treatment with DAAs in HCV-infected patients at EOT and for documenting SVR, but not at weeks 2 and 4 of treatment due to poor diagnostic performance.This study was supported by grants from Instituto de Salud Carlos III (ISCII; grant numbers PI20CIII/00004 to SR, and PI19CIII/00009 and PI22CIII/00019 to IM). This research was also supported by CIBER -Consorcio Centro de Investigación Biomédica en Red- (CB 2021), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea – NextGenerationEU (CB21/13/00044). DS-C is a ‘Sara Borrell’ researcher from ISCIII (grant nº CD20CIII/00001). No funding bodies had any role in study design, data collection, analysis, decision to publish, or manuscript preparation.S
Vitamins C and E downregulate vascular VEGF and VEGFR-2 expression in apolipoprotein-E-deficient mice
Anti-angiogenic therapy reduces both plaque growth and intimal neovascularization in apolipoprotein-E-deficient mice (apoE-/-). Vascular endothelial growth factor (VEGF) has been suggested as playing a role in the development of atherosclerosis. We examined the hypothesis that VEGF and VEGF receptor-2 (VEGFR-2) expression is upregulated in apoE-/- and, since it could be driven by oxidative stress, tested whether dietary supplementation with vitamins C and E could downregulate it.Two-month-old apoE-/- received vitamin C combined with alpha- or beta-tocopherol for 4 weeks. Aortic VEGF and VEGFR-2 expression were measured by RT-qPCR and western blot.ApoE-/- showed significantly higher expression of aortic VEGF and VEGFR-2 mRNA (P<0.001) and protein (P<0.001) than wild-type mice, as well as increased plasma VEGF (P<0.001). Vitamin C and alpha-tocopherol significantly reduced aortic VEGF and VEGFR-2 expression in apoE-/- (P<0.001), circulating VEGF (P<0.01) and plasma lipid peroxidation (P<0.01). apoE-/- receiving vitamin C and beta-tocopherol showed diminished lipid peroxidation and VEGFR-2, but only partial reduction of VEGF expression. These data demonstrate that augmented VEGF and VEGFR-2 expression in apoE-/- vasculature can be downregulated by vitamins C and E, at least partially through oxidative stress reduction. This novel mechanism could contribute to explaining the beneficial effects of antioxidant vitamins in experimental atherosclerosis
Room temperature polymorphism in WO_(3) produced by resistive heating of W wires
Polymorphous WO_(3) micro- and nanostructures have been synthesized by the controlled Joule heating of tungsten wires under ambient conditions in a few seconds. The growth on the wire surface is assisted by the electromigration process and it is further enhanced by the application of an external electric field through a pair of biased parallel copper plates. In this case, a high amount of WO_(3) material is also deposited on the copper electrodes, consisting of a few cm^(2) area. The temperature measurements of the W wire agrees with the values calculated by a finite element model, which has allowed us to establish the threshold density current to trigger the WO_(3) growth. The structural characterization of the produced microstructures accounts for the gamma-WO_(3) (monoclinic I), which is the common stable phase at room temperature, along with low temperature phases, known as delta-WO_(3) (triclinic) on structures formed on the wire surface and e-WO_(3) (monoclinic II) on material deposited on external electrodes. These phases allow for a high oxygen vacancies concentration, which is interesting in photocatalysis and sensing applications. The results could help to design experiments to produce oxide nanomaterials from other metal wires by this resistive heating method with scaling-up potential
Mentoría y recursos educativos para el Trabajo Fin de Grado del Grado en Física y del Grado en Ingeniería de Materiales
Depto. de Física de MaterialesFac. de Ciencias FísicasFALSEsubmitte
Estudio de soluciones para mejorar la operatividad y la respuesta del barco atracado en la dársena de África (Puerto de Las Palmas)
Nuevas formas de publicitar en los principales sectores empresariales en el contexto COVID-19 en el Perú
En este primer capítulo se definieron las bases teóricas para reconocer al mundo
publicitario considerando los conceptos básicos de la estrategia publicitaria. Como primer
punto se ha contextualizado las tendencias de consumo global para el año 2020, las que luego
se vieron afectadas por la llegada del COVID-19 a Perú. Se analizan los hechos que
influyeron en la vida de los consumidores peruanos como el distanciamiento social y la
cuarentena, los que ocasionaron el cambio de hábitos y comportamientos de compra
afectando el consumo de bienes y servicios.
En esta introducción se detallaron conceptos claves como tipos de publicidad, medios,
estrategia, presupuesto, eficacia y estrategia publicitaria. Asimismo, se presentó la situación
actual de la publicidad y los medios a nivel mundial, así como las estrategias adoptadas por
los anunciantes en el mundo y, por último, la inversión en publicidad en diferentes países.
Se estableció el objetivo y la hipótesis de investigación, la cual será contrastada a lo
largo de este estudio mediante la investigación cualitativa de los actores que intervienen en la
dinámica publicitaria: los anunciantes, los medios de comunicación y las agencias creativas y
centrales de medios.In this first chapter the theoretical bases were defined to recognize the advertising
world considering the basic concepts of advertising strategy. As a first point, the global
consumption trends for 2020 have been contextualized, which were later affected by the
11
arrival of COVID-19 in Peru. Facts that influenced the lives of Peruvian consumers are
analyzed, such as social distancing and quarantine, which caused a change in shopping habits
and affecting the consumption of goods and services.
In this introduction key concepts such as types of advertising, media, strategy, budget,
effectiveness and advertising strategy were detailed. Likewise, the current situation of
advertising and the media worldwide was presented, as well as the strategies adopted by
advertisers and, finally, the investment in advertising in different countries in the world.
The objective and the research hypothesis were established, which will be contrasted
throughout this study qualitative research of the actors involved in the advertising dynamics:
advertisers, the media, creative and media centers agencies
- …