A full probabilistic solution of the random linear fractional differential equation via the Random Variable Transformation technique

[EN] This paper provides a full probabilistic solution of the randomized fractional linear nonhomogeneous differential equation with a random initial condition via the computation of the first probability density function of the solution stochastic process. To account for most generality in our analysis, we assume that uncertainty appears in all input parameters (diffusion coefficient, source term, and initial condition) and that a wide range of probabilistic distributions can be assigned to these parameters. Throughout our study, we will consider that the fractional order of Caputo derivative lies in] 0,1], that corresponds to the main standard case. To conduct our analysis, we take advantage of the random variable transformation technique to construct approximations of the first probability density function of the solution process from a suitable infinite series representation. We then prove these approximations do converge to the exact density assuming mild conditions on random input parameters. Our theoretical findings are illustrated through 2 numerical examples.Ministerio de Economia y Competitividad, Grant/Award Number: MTM2017-89664-P; Programa de Ayudas de Investigacion y Desarrollo, Grant/Award Number: PAID-2014; UNiversitat Politecncia de ValenciaBurgos-Simon, C.; Calatayud-Gregori, J.; Cortés, J.; Navarro-Quiles, A. (2018). A full probabilistic solution of the random linear fractional differential equation via the Random Variable Transformation technique. Mathematical Methods in the Applied Sciences. 41(18):9037-9047. https://doi.org/10.1002/mma.4881S90379047411

Effects of tension stiffening and shrinkage on the flexural behavior of reinforced UHPFRC beams

[EN] This paper presents a study on the flexural behavior of Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) beams, which included conventional reinforcing bars. The study focuses on critical design aspects, such as concrete shrinkage and cracking implications on the tension-stiffening phenomenon. An experimental program with two different sized flexural reinforced UHPFRC beams was run. Beams were cast and tested in a four-point bending test (4PBT) using UHPFRC with different amounts of fibers: 130 and 160 kg/m(3) (1.66% and 2.00% in vol.) to cover a wide range of strain-softening and strain-hardening constitutive UHPFRC behaviors. A nonlinear finite element model (NLFEM) was developed to validate the mechanical tensile characterization of UHPFRC when applied to reinforced elements. Both shrinkage and tension-stiffening effects were considered to improve the model. After the NLFEM simulation, very reliable results were obtained at both the service and ultimate load levels compared to the experimental ones. Finally, some aspects about the design of reinforced UHPFRC cross-sections under bending forces are addressed and satisfactorily compared to the experimental results.This work forms part of Project "BIA2016-78460-C3-1-R" supported by the State Research Agency of Spain and the project "Rethinking coastal defence and Green-energy Service infrastructures through enHancEd-durAbiLity high-performance cement-based materials-ReSHEALience", funded by the European Union Horizon 2020 research and innovation programme under GA No 760824.Mezquida-Alcaraz, EJ.; Navarro-Gregori, J.; Martí Vargas, JR.; Serna Ros, P. (2021). Effects of tension stiffening and shrinkage on the flexural behavior of reinforced UHPFRC beams. Case Studies in Construction Materials. 15:1-28. https://doi.org/10.1016/j.cscm.2021.e007461281

Effects of concrete composition on transmission length of prestressing strands

The bond behaviour of prestressing strands in precast pretensioned concrete members, and its transmission length, depends on several factors. However, no consensus exists on the main parameters to be considered in the expressions to predict the transmission length. Usually when the concrete properties are considered, only the concrete compressive strength is included. This study analyzes the influence of concrete composition made up of different cement contents and water/cement ratios on the bond behaviour in transmission of seven-wire prestressing strands. The bond properties and the transmission lengths have been determined. The results show that the influence of the water/cement ratio is very small for concretes with lows cement contents, but the influence of the water/cement ratio on the transmission lengths is highly significant when cement content is high. The effect of cement content in the transmission lengths can reveal different tendencies based on the level of the water/cement ratioThe content of this article forms a part of research that the Universitat Politecnica de Valencia's Institute of Concrete Science and Technology (ICITECH) is presently conducting in conjunction with PREVALESA and ISOCRON. This study was funded by the Ministry of Education and Science and ERDF (Project BIA2006-05521). The authors wish to thank the above companies as well as the concrete structures laboratory technicians at the Universitat Politecnica de Valencia for their cooperation. Also, the authors wish to pay their respects to C.A. Arbelaez.Martí Vargas, JR.; Serna Ros, P.; Navarro Gregori, J.; Bonet Senach, JL. (2012). Effects of concrete composition on transmission length of prestressing strands. Construction and Building Materials. 27(1):350-356. https://doi.org/10.1016/j.conbuildmat.2011.07.038S35035627

Bond of 13 mm prestressing steel strands in pretensioned concrete members

This paper presents an experimental research work to determine both the transmission and the anchorage lengths of seven-wire prestressing steel strands in different concrete mixes. A testing technique based on a bond behavior analysis by measuring the force supported by the prestressing strand on a series of specimens with different embedment lengths has been used. Relationships between the average bond stress for both the transmission length and anchorage length as a function of the concrete compressive strength have been found. Equations to compute transmission and anchorage lengths of 13 mm prestressing strands have been obtained. The experimental results have been compared with the theoretical prediction from proposed equations in the literature and with experimental results from other authors. 2012 Elsevier Ltd. All rights reserved.The content of this article forms part of the research work that the Institute of Concrete Science and Technology (ICITECH) is presently conducting in conjunction with PREVALESA and ISOCRON. This study has been funded by the Spanish Ministry of Education and Science and ERDF (Project BIA2006-05521). The authors wish to thank the above companies as well as the concrete structures laboratory technicians at the Universitat Politecnica de Valencia for their cooperation. Finally, the authors also wish to pay their respects to C.A. Arbelaez.Martí Vargas, JR.; Serna Ros, P.; Navarro Gregori, J.; Pallarés Rubio, L. (2012). Bond of 13 mm prestressing steel strands in pretensioned concrete members. Engineering Structures. 41:403-412. https://doi.org/10.1016/j.engstruct.2012.03.056S4034124

Monitoring of cerebral autoregulaion during early mobilization owards personalization of post-stroke mobilization

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Neurons of the Dentate Molecular Layer in the Rabbit Hippocampus

The molecular layer of the dentate gyrus appears as the main entrance gate for information into the hippocampus, i.e., where the perforant path axons from the entorhinal cortex synapse onto the spines and dendrites of granule cells. A few dispersed neuronal somata appear intermingled in between and probably control the flow of information in this area. In rabbits, the number of neurons in the molecular layer increases in the first week of postnatal life and then stabilizes to appear permanent and heterogeneous over the individuals’ life span, including old animals. By means of Golgi impregnations, NADPH histochemistry, immunocytochemical stainings and intracellular labelings (lucifer yellow and biocytin injections), eight neuronal morphological types have been detected in the molecular layer of developing adult and old rabbits. Six of them appear as interneurons displaying smooth dendrites and GABA immunoreactivity: those here called as globoid, vertical, small horizontal, large horizontal, inverted pyramidal and polymorphic. Additionally there are two GABA negative types: the sarmentous and ectopic granular neurons. The distribution of the somata and dendritic trees of these neurons shows preferences for a definite sublayer of the molecular layer: small horizontal, sarmentous and inverted pyramidal neurons are preferably found in the outer third of the molecular layer; vertical, globoid and polymorph neurons locate the intermediate third, while large horizontal and ectopic granular neurons occupy the inner third or the juxtagranular molecular layer. Our results reveal substantial differences in the morphology and electrophysiological behaviour between each neuronal archetype in the dentate molecular layer, allowing us to propose a new classification for this neural population

Deep-sequencing reveals broad subtype-specific HCV resistance mutations associated with treatment failure

A percentage of hepatitis C virus (HCV)-infected patients fail direct acting antiviral (DAA)-based treatment regimens, often because of drug resistance-associated substitutions (RAS). The aim of this study was to characterize the resistance profile of a large cohort of patients failing DAA-based treatments, and investigate the relationship between HCV subtype and failure, as an aid to optimizing management of these patients. A new, standardized HCV-RAS testing protocol based on deep sequencing was designed and applied to 220 previously subtyped samples from patients failing DAA treatment, collected in 39 Spanish hospitals. The majority had received DAA-based interferon (IFN) a-free regimens; 79% had failed sofosbuvir-containing therapy. Genomic regions encoding the nonstructural protein (NS) 3, NS5A, and NS5B (DAA target regions) were analyzed using subtype-specific primers. Viral subtype distribution was as follows: genotype (G) 1, 62.7%; G3a, 21.4%; G4d, 12.3%; G2, 1.8%; and mixed infections 1.8%. Overall, 88.6% of patients carried at least 1 RAS, and 19% carried RAS at frequencies below 20% in the mutant spectrum. There were no differences in RAS selection between treatments with and without ribavirin. Regardless of the treatment received, each HCV subtype showed specific types of RAS. Of note, no RAS were detected in the target proteins of 18.6% of patients failing treatment, and 30.4% of patients had RAS in proteins that were not targets of the inhibitors they received. HCV patients failing DAA therapy showed a high diversity of RAS. Ribavirin use did not influence the type or number of RAS at failure. The subtype-specific pattern of RAS emergence underscores the importance of accurate HCV subtyping. The frequency of “extra-target” RAS suggests the need for RAS screening in all three DAA target regions

Generational distribution of a Candida glabrata population: Resilient old cells prevail, while younger cells dominate in the vulnerable host.

Similar to other yeasts, the human pathogen Candida glabrata ages when it undergoes asymmetric, finite cell divisions, which determines its replicative lifespan. We sought to investigate if and how aging changes resilience of C. glabrata populations in the host environment. Our data demonstrate that old C. glabrata are more resistant to hydrogen peroxide and neutrophil killing, whereas young cells adhere better to epithelial cell layers. Consequently, virulence of old compared to younger C. glabrata cells is enhanced in the Galleria mellonella infection model. Electron microscopy images of old C. glabrata cells indicate a marked increase in cell wall thickness. Comparison of transcriptomes of old and young C. glabrata cells reveals differential regulation of ergosterol and Hog pathway associated genes as well as adhesion proteins, and suggests that aging is accompanied by remodeling of the fungal cell wall. Biochemical analysis supports this conclusion as older cells exhibit a qualitatively different lipid composition, leading to the observed increased emergence of fluconazole resistance when grown in the presence of fluconazole selection pressure. Older C. glabrata cells accumulate during murine and human infection, which is statistically unlikely without very strong selection. Therefore, we tested the hypothesis that neutrophils constitute the predominant selection pressure in vivo. When we altered experimentally the selection pressure by antibody-mediated removal of neutrophils, we observed a significantly younger pathogen population in mice. Mathematical modeling confirmed that differential selection of older cells is sufficient to cause the observed demographic shift in the fungal population. Hence our data support the concept that pathogenesis is affected by the generational age distribution of the infecting C. glabrata population in a host. We conclude that replicative aging constitutes an emerging trait, which is selected by the host and may even play an unanticipated role in the transition from a commensal to a pathogen state.post-print10768 K

Influence of the fiber reinforcement in concrete under direct shear

Shear behaviour in cracked concrete is still a matter of discussion into the scientific community. This paper reports on an experimental campaign which focused on the shear behaviour of pre-cracked concrete under direct shear. The push-off test with confined specimen is used to this aim. The influence of the granular skeleton (one mix with aggregate maximum size of20 mm, and the other with12 mm), concrete compressive strength (30 and 50 MPa), shear reinforcement (close stirrups, steel fibres or plain concrete) and the initial crack width (fixedin two levels: low (0 mm) and high (1mm)) are studied. Results show that the reinforcement transmits shear stress up to a slip of 0.4 mm (for uncon-fined specimens), and1 mm (for confined ones). After that, macro roughness and confinement force are the mechanisms which transmit shear stress

Upgrading the push-off test to study the mechanisms of shear transfer in FRC elements

In this paper an upgrading of the push-off test in pre-cracked specimens is presented. The test is performed under conditions of crack control both in the pre-cracking and in the push-off stages. To this end, transversal forces to control the crack opening are introduced. Additionally, this confinement system avoids unnecessary movements that may introduce strains in the specimen. It is also included the methodology to perform the pre-cracking of the specimens prior to the push-off test. Specimens of 40 MPa of concrete compressive strength are used with two types of steel fibers type as well as with transverse reinforcement. It can be concluded that it is possible to perform the push-off test under crack control as it is shown with the results of crack width obtained with different measurement techniques. Different types of behavior after cracking can be detected such as hardening or the evolution of post-cracking residual stresses