Static and Dynamic Behavior of Composite Concrete-Based Beams with Embedded Polymer/FRP Components

AbstractRecently, the seismic reassessment led to justify the behavior of concrete structures and to dispose members able to dissipate energy through a ductile behavior. In this respect, the present work aims to propose a new concrete-composite beam design, which allows the resumption of the shearing action under static and dynamic loads. The proposed design consists to incorporate in the tensile zone of the beam a rectangular polymer member wrapped by FRP, in order to prevent lateral deformation and to significantly enhance bending and shear strengths. A detailed experimental program is carried out on simply supported composite beams under typical four-point bending loads. Experiments are completed by nonlinear finite element modeling based on a local approach to simulate the real behavior of such elements and to allow a better understanding of experimental observations. The average test and numerical results in terms of overall and observed response are emphasized and discussed. In addition, the influence of the shear strength generated by static and dynamic loads as well as the adequate parameters improving the flexural capacity and ductility are assessed to highlight the mechanical performances of the new beam compared to classical RC beams

Lawsonia intracellularis regulates nuclear factor-κB signalling pathway during infection

Lawsonia intracellularis is the etiological agent of proliferative enteropathy (PE) in pigs, horses and wide range of mammals. Little is known about the role of innate immune response during L. intracellularis infection. In this study, we investigated the nuclear factor-κB (NF-κB)-regulated immune response against infection of a clinical strain Dkp23 and a live-attenuated Enterisol vaccine strain in PK-15 cells. We found that expression of NF-κB target genes TNF-α, IFN-γ, IL-6 and IL-8 were modulated during the course of infection. At 5 dpi, there was a significant increase in p65 NF-κB activation, including protein nuclear translocation and phosphorylation, synchronous with the induction of IL-6, IFN-γ and IL-8 expression in L. intracellularis infected cells, especially for Enterisol vaccine strain-infected cells. This result suggests that NF-κB signalling level is induced when L. intracellularis bacterial load peaks at 5 dpi. The induction of pro-inflammatory cytokines expression is consistent with the decreased viability of L. intracellularis-infected cells especially that of the vaccine strain. There were no significant changes in NF-κB signalling between vaccine and Dkp23 infection in PK-15 cells, except for moderate levels of differences in NF-κB target genes expression which might be a reflection of differences in intracellular bacterial load. Overall, the data presented here indicate a correlation between the induction of NF-κB signalling and the L. intracellularis bacterial load in PK-15 cells.</p

Characterisation of autophagy disruption in the ileum of pigs infected with Lawsonia intracellularis

Lawsonia intracellularis is the aetiological agent of proliferative enteropathy, an enteric disease endemic in swine. Survival in its intracellular niche of the ileum epithelial lining requires the capacity to subvert, repress or exploit the host immune response to create an environment conducive to bacterial propagation. To better understand how L. intracellularis survives in its intracellular niche, we have performed an investigation into the dynamic relationship between infection and the host autophagy response by immunohistochemistry in experimentally infected porcine ileum samples. Beclin1, a protein required early in the autophagy pathway was observed to be distributed with a basal to apical concentration gradient in the crypts of healthy piglets, whilst infected piglets were observed to have no gradient of distribution and an increase in the presence of Beclin1 in crypts with histological characteristics of L. intracellularis residence. Detecting microtubule-associated protein light chain 3 (LC3) is used as a method for monitoring autophagy progression as it associates with mature autophagosomes. For LC3 there was no notable change in signal intensity between crypts with characteristic L. intracellularis infection and healthy crypts of uninfected pigs. Finally, as p62 is degraded with the internal substrate of an autophagosome it was used to measure autophagic flux. There was no observed reduction or redistribution of p62. These preliminary results of the autophagy response in the ileum suggest that L. intracellularis affects autophagy. This disruption to host ileum homeostasis may provide a mechanism that assists in bacterial propagation and contributes to pathogenesis

Physicochemical characteristics and pollen spectrum of some north-east Algerian honeys.

The qualities of seventeen honey samples harvested from the North-East areas of Algeria were evaluated by determining the pollen spectrum, pollen number quantity and physicochemical attributes. Pollen analysis can therefore be useful to determine the geographical and botanical origin of honeys. The following determinations were carried out: pH, density, acidity (free, lactone and total), moisture, electrical conductivity,  hydroxymethylfurfural, diastase activity, apparent sucrose, and proteins.The results obtained in the present study show the variability of chemical composition of the honey samples. It proved that nine natural honeys are of blossoming origin; suitable for consumption and that one (T5 conferred Bougous) can be used with fine dietetics, it is very rich in pollen which is regarded as protein source. The remainder, eight honeys, were not in conformity with the International Regulatory Standards, their sugar contents (Sucrose) and hydroxymethylfurfural exceeded the InternationalRegulatory Standards Review by the International Honey Commission, this was probably due to use of syrup for the over-feeding the bees during the spring. The sample Bouhachana (G1) had high water content (more than 20%), low density and electrical conductivity higher than 5 μS/cm, which makes it likely to undergo fermentation and degradation. Honeys of Guerguour (T1), Boutheldja (T2) and Bouhadjar (T3) had pH lower than the European standards concerning the quality control of the foodstuffs (exp. honey). These samples are fragile; so we cannot preserve them for a long period. The palynological analysis (qualitative and quantitative) of the harvested samples in the area, showed the absence of a honey obtained from only one melliferous plant. All honeys are polyfloral exits of theseveral plant species visited by the worker bees during their blossoming periods. Three families are the most represented in the groups of pollen of accompaniment (the secondary pollen ranged between 16-45%) and the pollen considered as rare (minor pollen 3-15%) in the counted total number of the pollen grains in 10 grams of honey. These forager honey families are: Myrtaceae presented by the Eucalyptus, Papilionaceae presented by Hedysarum coronarium which is a forager plant characterized by a very vast surface of development, and Rosaceae represented byorchard and forest species.The pollen grain number counted in honeys is very significant (between 80 000 and 24 832 000pollen grain), what makes it possible to classify the samples analyzed among the categories rich in pollen

Short and canonical GRBs

Within the "fireshell" model for the Gamma-Ray Bursts (GRBs) we define a "canonical GRB" light curve with two sharply different components: the Proper-GRB (P-GRB), emitted when the optically thick fireshell of electron-positron plasma originating the phenomenon reaches transparency, and the afterglow, emitted due to the collision between the remaining optically thin fireshell and the CircumBurst Medium (CBM). We outline our "canonical GRB" scenario, with a special emphasis on the discrimination between "genuine" and "fake" short GRBs.Comment: 4 pages, 3 figures, in the Proceedings of the "Gamma Ray Bursts 2007" meeting, November 5-9, 2007, Santa Fe, New Mexico, US

The high partial wave phenomenon of spin changing atomic transitions

The collisional transition between two highly excited atomic states with different spin is investigated theoretically. Taking helium-like n1S − n3P as an example, it is found that the transition is driven in the highly ion-ized Fe ion purely by exchange, and the cross section becomes increasingly dominated by partial waves of high orbital angular momentum as the scattering energy increases. Whereas for the near-neutral Li ion the transition is dominated by channel coupling in low partial waves. Analytical bench-marks and numerical methods are developed for the accurate calculation of the exchange integral at high angular momentum. It is shown how the partial wave and energy dependence of the collision strength for high n spin changing transitions in the highly ionized ion is related to the overlap of the extended atomic orbitals.</p

NuMDG: A New Tool for Multiway Decision Graphs Construction

Multiway Decision Graphs (MDGs) are a canonical representation of a subset of many-sorted first-order logic. This subset generalizes the logic of equality with abstract types and uninterpreted function symbols. The distinction between abstract and concrete sorts mirrors the hardware distinction between data path and control. Here we consider ways to improve MDGs construction. Efficiency is achieved through the use of the Generalized-If-Then-Else (GITE) commonly operator in Binary Decision Diagram packages. Consequently, we review the main algorithms used for MDGs verification techniques. In particular, Relational Product and Pruning by Subsumption are algorithms defined uniformly through this single GITE operator which will lead to a more efficient implementation. Moreover, we provide their correctness proof. This work can be viewed as a way to accommodate the ROBBD algorithms to the realm of abstract sorts and uninterpreted functions. The new tool, called NuMDG, accepts an extended SMV language, supporting abstract data sorts. Finally, we present experimental results demonstrating the efficiency of the NuMDG tool and evaluating its performance using a set of benchmarks from the SMV package

A fast and robust method for full genome sequencing of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Type 1 and Type 2

PRRSV is a positive-sense RNA virus with a high degree of genetic variability among isolates. For diagnostic sensitivity and vaccine design it is essential to monitor PRRSV genetic diversity. However, to date only a few full genome sequences of PRRSV isolates have been made publicly available. In the present study, fast and robust methods for long range RT-PCR amplification and subsequent next generation sequencing (NGS) were developed and validated on nine Type 1 and nine Type 2 PRRSV viruses. The methods generated robust and reliable sequences both on primary material and cell culture adapted viruses and the protocols performed well on all three NGS platforms tested (Roche 454 FLX, Illumina HiSeq2000, and Ion Torrent PGM™ Sequencer). These methods will greatly facilitate the generation of more full genome PRRSV sequences globally