Reorganization of Coherent Structures Downstream a Circular Cylinder Located between Two Parallel Walls

Experiments were performed at low Reynolds numbers in the range 75 Re 275 in the wake of a circular cylinder of dc diameter placed symmetrically between two parallel walls of H height. 2D2C particle image velocimetry (PIV) was used to investigate the flow downstream the cylinder. In the unsteady flow regime downstream the cylinder, the detached primary vortices (Pi) interact with walls generating secondary ones (Pi’) and modify the cylinder wake dynamic. The kinematical properties (advection velocity, circulation, rotation kinetic energy, etc.) of the generated secondary vortices are studied and compared with the primary ones in order to show how the walls influence the von Kármán vortex street. The authors propose here a relation between the circulations and kinetic energies of primary and secondary vortices

Effect of chemokine receptor CXCR4 on hypoxia-induced pulmonary hypertension and vascular remodeling in rats

<p>Abstract</p> <p>Background</p> <p>CXCR4 is the receptor for chemokine CXCL12 and reportedly plays an important role in systemic vascular repair and remodeling, but the role of CXCR4 in development of pulmonary hypertension and vascular remodeling has not been fully understood.</p> <p>Methods</p> <p>In this study we investigated the role of CXCR4 in the development of pulmonary hypertension and vascular remodeling by using a CXCR4 inhibitor AMD3100 and by electroporation of CXCR4 shRNA into bone marrow cells and then transplantation of the bone marrow cells into rats.</p> <p>Results</p> <p>We found that the CXCR4 inhibitor significantly decreased chronic hypoxia-induced pulmonary hypertension and vascular remodeling in rats and, most importantly, we found that the rats that were transplanted with the bone marrow cells electroporated with CXCR4 shRNA had significantly lower mean pulmonary pressure (mPAP), ratio of right ventricular weight to left ventricular plus septal weight (RV/(LV+S)) and wall thickness of pulmonary artery induced by chronic hypoxia as compared with control rats.</p> <p>Conclusions</p> <p>The hypothesis that CXCR4 is critical in hypoxic pulmonary hypertension in rats has been demonstrated. The present study not only has shown an inhibitory effect caused by systemic inhibition of CXCR4 activity on pulmonary hypertension, but more importantly also has revealed that specific inhibition of the CXCR4 in bone marrow cells can reduce pulmonary hypertension and vascular remodeling via decreasing bone marrow derived cell recruitment to the lung in hypoxia. This study suggests a novel therapeutic approach for pulmonary hypertension by inhibiting bone marrow derived cell recruitment.</p

Physiological and Morphological Aspects of Aedes aegypti Developing Larvae: Effects of the Chitin Synthesis Inhibitor Novaluron

Population control of the dengue vector mosquito, Aedes aegypti, is difficult due to many reasons, one being the development of resistance to neurotoxic insecticides employed. The biosynthesis of chitin, a major constituent of insect cuticle, is a novel target for population control. Novaluron is a benzoylphenylurea (BPU) that acts as a chitin synthesis inhibitor, already used against mosquitoes. However, information regarding BPU effects on immature mosquito stages and physiological parameters related with mosquito larval development are scarce. A set of physiological parameters were recorded in control developing larvae and novaluron was administered continuously to Ae. aegypti larvae, since early third instar. Larval instar period duration was recorded from third instar until pupation. Chitin content was measured during third and fourth instars. Fourth instars were processed histochemically at the mesothorax region, stained with hematoxylin and eosin (HE) for assessment of internal tissues, and labeled with WGA-FITC to reveal chitinized structures. In control larvae: i) there is a chitin content increase during both third and fourth instars where late third instars contain more chitin than early fourth instars; ii) thoracic organs and a continuous cuticle, closely associated with the underlying epidermis were observed; iii) chitin was continuously present throughout integument cuticle. Novaluron treatment inhibited adult emergence, induced immature mortality, altered adult sex ratio and caused delay in larval development. Moreover, novaluron: i) significantly affected chitin content during larval development; ii) induced a discontinuous and altered cuticle in some regions while epidermis was often thinner or missing; iii) rendered chitin cuticle presence discontinuous and less evident. In both control and novaluron larvae, chitin was present in the peritrophic matrix. This study showed quantitatively and qualitatively evidences of novaluron effects on Ae. aegypti larval development. To our knowledge, this is the first report describing histological alterations produced by a BPU in immature vector mosquitoes

A strategy to discover new organizers identifies a putative heart organizer

Organizers are regions of the embryo that can both induce new fates and impart pattern on other regions. So far, surprisingly few organizers have been discovered, considering the number of patterned tissue types generated during development. This may be because their discovery has relied on transplantation and ablation experiments. Here we describe a new approach, using chick embryos, to discover organizers based on a common gene expression signature, and use it to uncover the anterior intestinal portal (AIP) endoderm as a putative heart organizer. We show that the AIP can induce cardiac identity from non-cardiac mesoderm and that it can pattern this by specifying ventricular and suppressing atrial regional identity. We also uncover some of the signals responsible. The method holds promise as a tool to discover other novel organizers acting during development

Effets des ondes de choc extracorporelles sur la douleur, le prurit et les caractéristiques des cicatrices de patients brûlés graves (2ème degré profond et 3ème degré)

Introduction: Severely burned patients are exposed to many unpleasant symptoms, such as pain, itching sensations and changes in the appearance of their scars that become dysesthetic, and this throughout their recovery, which can last for months or even years. The specialized centers offer therapies adapted to these patients such as the wearing of compressive clothing, gels, scar massages, orthotics, stretching and postures, etc.; but despite this, patients always complain of the same symptoms.Objective: A systematic review to estimate whether extracorporeal shock waves, as an adjuvant treatment, could significantly decrease the intensity of these symptoms.Methods: The research was conducted on three databases: Pubmed, Cochrane Library and Direct Science. Six randomized clinical trials were selected to study the effects of extracorporeal shock waves, compared to one placebo for four of them, or only conventional therapy for the other two. The three main outcomes were the reduction of pain, the reduction of pruritus and the modification of scar characteristics.Results and analysis: The comparison of the articles shows significant results (p<0.05) concerning the reduction of pain, pruritus and thickness of scars. However, these results are of low quality due to the small number of studies and patients (267 in total) and the risk of significant bias in some studies. For characteristic changes, based on the Vancouver Scar Scale (VSS), the results are not significant neither consistent between studies.Conclusion: The extracorporeal shock waves seem to show an effectiveness in the management of scars of major burns, especially on the reduction of pain and pruritus, but additional studies would be needed to scientifically confirm this result.Introduction : les patients grands brûlés sont exposés à de nombreux symptômes désagréables, tels que la douleur, les sensations de démangeaisons et la modification de l’aspect de leurs cicatrices qui deviennent inesthétiques, et ce tout au long de leur guérison qui peut durer des mois voire des années. Les centres spécialisés proposent des thérapeutiques adaptées à ces patients tels que le port de vêtements compressifs, des gels, des massages cicatriciels, des orthèses, des étirements et postures, etc ; mais malgré cela, les patients se plaignent toujours des mêmes symptômes. Objectif : une revue de littérature pour estimer si les ondes de chocs extracorporelles, en tant que traitement adjuvant, pourraient diminuer considérablement l’intensité de ces symptômes. Méthodologie : la recherche a été effectuée sur trois bases de données : Pubmed, Cochrane Library et Science directe. Six essais cliniques randomisés ont été sélectionnés pour étudier les effets des ondes de chocs extracorporelles, comparées à un placebo pour quatre d’entre eux, ou bien seulement à de la thérapie conventionnelle pour les deux autres. Les trois critères de jugement principaux étaient la diminution de la douleur, du prurit et la modification des caractéristiques des cicatrices. Résultats et analyse : la comparaison des articles montre des résultats significatifs (p<0,05) concernant la diminution de la douleur, du prurit et de l’épaisseur des cicatrices. Néanmoins ces résultats sont de faible qualité du fait du petit nombre d’études et de patients (267 au total) ainsi que du risque de biais important pour certaines études. Pour les modifications des caractéristiques, d’après la Vancouver Scar Scale (VSS), les résultats ne sont pas significatifs ni concordants entre les études. Conclusion : les ondes de chocs extracorporelles semblent montrer une efficacité dans la prise en charge des cicatrices de grands brûlés, notamment sur la diminution de douleur et de prurit, mais des études supplémentaires seraient nécessaires afin de confirmer scientifiquement ce résultat

Evaluation of the intention to shift to public transit in Saudi Arabia

Public transit (PT) is the backbone of a sustainable transport system. This study aims to investigate commuters’ initial intentions to shift to PT in a car-oriented city without a PT, quantifying the direct economic and environmental impacts. The study considers data from a recent survey conducted in Medina, Saudi Arabia. Analyses are based on a stated-preference (SP) survey in conjunction with spatial analysis approaches. SP results show that 53% of participants are willing to shift to PT, with no spatial autocorrelation existing between the participants’ willingness to use PT and their residential zones. Logistic regression indicates that participants who used PT abroad are more likely to shift whenever PT becomes available in their city. Equally, gender and vehicular occupancy rate determine participants’ intention to shift to PT. The results show that for each 1% of would-be PT commuters, a reduction of 0.79% in CO2 emissions is obtained

Bioefficacy of Azadirachtin in Controlling Culex pipiens pipiens (Diptera: Culicidae)

Abstract Azadirachtin was tested for its effects against First P P and second instars larvae of mosquito Culex pipiens pipiens (Diptera: Culicidae), laboratory reared larvae were exposed to 0.125 ; 0.250; 0.500 and 0.750 mg/ L of azadirachtin in laboratory of biology animal application, biology Department , university of Badji Mokhtar, Annaba, Algeria