Collisions in a liquid fluidized bed

Collisional phenomena in a solid–liquid flow were studied in terms of two parameters: the collision frequency and the coefficient of restitution. Experimental measurements of these parameters were conducted inside a liquid fluidized bed by particle tracking in an index-matched array. Collision detection was based on the use of a peak acceleration threshold of the instantaneous speed of colored tracers. The measurements of collision frequency were compared with the theoretical expression derived from the kinetic theory for granular flow (KTGF). The normal and tangential restitution coefficients were measured from the trajectories before and after contact for both particle–particle and particle–wall collisions. A comparison with previous theoretical and experimental works is presented and discussed

Vascular endothelial growth factor in developing ovine lung: endogenous expression and effects of exogenous administration on respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis in children with nearly all children infected by two years of age. Preterm infants and infants with cardiopulmonary compromise or immunodeficiency are at increased risk for severe RSV disease. However, a high percentage of hospitalizations due to severe RSV disease occur in otherwise healthy infants. Severe RSV disease is characterized by bronchiolitis and airway obstruction secondary to sloughed epithelial cells, cellular debris and inflammatory cells that can partially occlude the airway lumen. There is currently no licensed vaccine to prevent RSV infection. The purpose of this study was to develop a model of RSV infection in the newborn lamb using a human strain of RSV, strain A2. The pulmonary pathology and cellular localization of antigen was determined, in addition to the viral effect on the expression of epithelial innate immune genes, surfactant proteins A and D (SP-A and SP-D respectively) and sheep beta-defensin-1 (SBD-1). Pulmonary lesions were characterized by suppurative bronchiolitis with multifocal alveolar consolidation and peak pulmonary lesions at day 6 post-infection. RSV infection increased expression of SP-A and SBD-1, which demonstrates alteration of innate immune responses caused by RSV A2. Using this model, lambs were pretreated with exogenous human recombinant vascular endothelial growth factor (rhVEGF) prior to RSV infection. VEGF is a known endothelial mitogen, but also plays an important pulmonary role in surfactant protein production, epithelial cell proliferation, and epithelial cell survival. VEGF administration prior to RSV infection decreased both viral load and pulmonary pathology at peak infection - 6 days post-infection. In addition, VEGF increased the expression of SP-A and SBD-1 showing that VEGF can induce expression of important epithelial innate immune genes. VEGF pretreatment altered epithelial cell proliferation in RSV infected animals at day 4 post-infection. In the final part of this study, the effect of ontogeny on pulmonary endogenous VEGF expression was investigated. The results of this study demonstrate that the expression of major VEGF isoforms are differentially regulated with high pulmonary VEGF mRNA expression in prenatal lamb lung and low expression in adult lung. However, mRNA expression diverged from the protein profile with low VEGF protein expression in prenatal lung and high VEGF protein expression in adult lung, demonstrating tight translational regulation to maintin appropriate VEGF concentrations during development

Effects of the vasoactive intestinal peptide (VIP) and related peptides on glioblastoma cell growth in vitro

The growth rate of numerous cancer cell lines is regulated in part by actions of neuropeptides of the vasoactive intestinal peptide (VIP) family, which also includes pituitary adenylate cyclase-activating peptide (PACAP), glucagon, and peptide histidine/isoleucine (PHI). The aim of this work was to investigate the effect of these peptides on the growth of the rat glioblastoma cell line C6 in vitro. We also sought to determine which binding sites were correlated with the effects observed. Proliferation studies performed by means of a CyQuant trade mark assay showed that VIP and PACAP strongly stimulated C6 cell proliferation at most of the concentrations tested, whereas PHI increased cell proliferation only when associated with VIP. Two growth hormone-releasing factor (GRF) derivatives and the VIP antagonist hybrid peptide neurotensin-VIP were able to inhibit VIP-induced cell growth stimulation, even at very low concentrations. Binding experiments carried out on intact cultured C6 cells, using 125I-labeled VIP and PACAP as tracers, revealed that the effects of the peptides on cell growth were correlated with the expression on C6 cells of polyvalent high-affinity VIP-PACAP binding sites and of a second subtype corresponding to very high-affinity VIP-selective binding species. The latter subtype, which interacted poorly with PACAP with a 10,000-fold lower affinity than VIP, might mediate the antagonist effects of neurotensin- VIP and of both GRF derivatives on VIP-induced cell growth stimulation

Precision farming uses typology in arable crop-oriented farms in northern France

International audienceThe adoption of precision farming techniques (PFTs) has been widely studied targeting specific PFT or farming systems along with the potential benefits of these PFTs in terms of yield or input use. However, few studies have examined how PFTs are adopted and used at the farm level. In this study a preliminary investigation was made of on-farm PFT uses in the Oise region (northern France). Three main PFTs were identified in the area: Global Navigation Satellite Systems (GNSS) guidance, section control, and variable rate (VR) application. For each farm, the use of every PFT was defined by the technical characteristics of the equipment, the field operation(s) concerned, the targeted crop(s), the aim of the use, the PFT adoption drivers, and the perceived impacts by the farmers. These different variables were combined into a typology of PFT uses. The results show that most of the farms combined GNSS guidance for all technical operations and section control, whereas VR application was less common. Section control was largely used by farmers for liquid fertilizers and phytochemical spraying. The typology shows three to five types of use for each PFT, which differ in terms of technique adoption drivers, e.g. reducing on-farm work or adaptation to field morphology. According to literature, economic impacts were found to be the most frequent, however farmers seemed unable to quantify them. Social impacts such as reduced work time and fatigue were also frequent and are becoming the main motivation for using PFT on farms studied. Further research is needed to assess the use trajectories of PFT along with the motivations of each PFT use

Broadband integrated beam splitter using spatial adiabatic passage

Light routing and manipulation are important aspects of integrated optics. They essentially rely on beam splitters which are at the heart of interferometric setups and active routing. The most common implementations of beam splitters suffer either from strong dispersive response (directional couplers) or tight fabrication tolerances (multimode interference couplers). In this paper we fabricate a robust and simple broadband integrated beam splitter based on lithium niobate with a splitting ratio achromatic over more than 130 nm. Our architecture is based on spatial adiabatic passage, a technique originally used to transfer entirely an optical beam from a waveguide to another one that has been shown to be remarkably robust against fabrication imperfections and wavelength dispersion. Our device shows a splitting ratio of 0.52$\pm$0.03 and 0.48$\pm$0.03 from 1500\,nm up to 1630\,nm. Furthermore, we show that suitable design enables the splitting in output beams with relative phase 0 or $\pi$. Thanks to their independence to material dispersion, these devices represent simple, elementary components to create achromatic and versatile photonic circuits

Exogenous administration of vascular endothelial growth factor prior to human respiratory syncytial virus a2 infection reduces pulmonary pathology in neonatal lambs and alters epithelial innate immune responses

Human respiratory syncytial virus (RSV) affects thousands of children every year. Vascular endothelial growth factor (VEGF) is a regulator of vasculogenesis, pulmonary maturation, and immunity. In order to test the extent to which VEGF may alter RSV infection, 4 groups of lambs received either human recombinant VEGF (rhVEGF) or phosphate-buffered saline (PBS) pretreatment followed by inoculation with human RSV strain A2 or sterile medium. Lambs in each group were sacrificed at 2, 4, and 6 days post infection. Expression of surfactant protein-A (SP-A), surfactant protein-D (SP-D), sheep β-defensin-1 (SBD-1), tumor necrosis factor α (TNFα), interleukin (IL)-6, IL-8, interferon β, and endogenous VEGF were measured to determine effect of rhVEGF pretreatment. RSV lambs pretreated with rhVEGF had reduced viral mRNA and decreased pulmonary pathology at day 6. Pretreatment with rhVEGF increased mRNA expression of SP-A, SBD-1, and TNFα, with alteration of expression in RSV lambs. Endogenous VEGF mRNA levels were increased at day 2 regardless of pretreatment. Pretreatment with rhVEGF increased pulmonary cellular proliferation in RSV lambs at day 4 post infection. Overall, these results suggest that pretreatment with rhVEGF protein may have therapeutic potential to decrease RSV viral load, decrease pulmonary lesion severity, and alter both epithelial innate immune responses and epithelial cell proliferation

Neurones à kisspeptine et oestrogènes. Etude chez le poisson zèbre et le loup de mer. Kisspeptin neurones and their relationships with estrogens. Study in two fish species the zebrafish and the sea bass.

Supported by EU Project LIFECYCLE (FP7-222719-1) to OK and SZ, NEMO project to OK and ACOM/2010/086-GV. SE was supported by a JAE-Predoc (CSIC, Spain).Peer Reviewe

Differential expression of cytokine transcripts in neonatal and adult ovine alveolar macrophages in response to respiratory syncytial virus or toll-like receptor ligation

Alveolar macrophages (AMϕs) secrete regulatory molecules that are believed to be critical in maintaining normal lung homeostasis. However, in response to activating signals, AMϕs have been shown to become highly phagocytic cells capable of secreting significant levels of pro-inflammatory cytokines. There is evidence to suggest that susceptibility of Mϕ subpopulations to viral infection, and their subsequent cytokine/chemokine response, is dependent on age of the host. In the present study, we compared bovine respiratory syncytial virus (BRSV) replication and induction of cytokine responses in neonatal ovine AMϕs to those cells isolated from adult animals. While neonatal AMϕs could be infected with BRSV, viral replication was limited as previously shown for AMϕs from mature animals. Interestingly, following BRSV infection, peak mRNA levels of IL-1β and IL-8 in neonatal AMϕ were several fold higher than levels induced in adult AMϕs. In addition, peak mRNA expression for the cytokines examined occurred at earlier time points in neonatal AMϕs compared to adult AMϕs. However, the data indicated that viral replication was not required for the induction of specific cytokines in either neonatal or adult AMϕs. TLR3 and TLR4 agonists induced significantly higher levels of cytokine transcripts than BRSV in both neonatal and adult AMϕs. It was recently proposed that immaturity of the neonatal immune system extends from production of pro-inflammatory cytokines to regulation of such responses. Differential regulation of cytokines in neonatal AMϕs compared to adult AMϕs in response to RSV could be a contributory factor to more severe clinical episodes seen in neonates