A Reduced Order Model for Preliminary Design and Performance Prediction of Tapered Inducers: Comparison with Numerical Simulations

The article recalls the recent development of a reduced order model for the preliminary design, geometric definition and noncavitating performance prediction of tapered-hub, variable-pitch, mixed-flow inducers, and illustrates its application to a typical three-bladed, high-head inducer for liquid propellant rocket engines. The mean axisymmetric flow field at the trailing edge of the inducer blades and the noncavitating head coefficient at both design and off-design conditions are then compared with those obtained from the numerical flow simulations generated by a commercial CFD code. Together with earlier experimental validations, the results dramatically confirm the capability of the proposed model to generate interpretative and useful engineering solutions of the inducer preliminary design problem at a negligible fraction of the computational cost required by 3D numerical simulations

DISC1–ATF4 transcriptional repression complex: dual regulation of the cAMP-PDE4 cascade by DISC1

Disrupted-In-Schizophrenia 1 (DISC1), a risk factor for major mental illnesses, has been studied extensively in the context of neurodevelopment. However, the role of DISC1 in neuronal signaling, particularly in conjunction with intracellular cascades that occur in response to dopamine, a neurotransmitter implicated in numerous psychiatric disorders, remains elusive. Previous data suggest that DISC1 interacts with numerous proteins that impact neuronal function, including activating transcription factor 4 (ATF4). In this study, we identify a novel DISC1 and ATF4 binding region in the genomic locus of phosphodiesterase 4D (PDE4D), a gene implicated in psychiatric disorders. We found that the loss of function of either DISC1 or ATF4 increases PDE4D9 transcription, and that the association of DISC1 with the PDE4D9 locus requires ATF4. We also show that PDE4D9 is increased by D1-type dopamine receptor dopaminergic stimulation. We demonstrate that the mechanism for this increase is due to DISC1 dissociation from the PDE4D locus in mouse brain. We further characterize the interaction of DISC1 with ATF4 to show that it is regulated via protein kinase A-mediated phosphorylation of DISC1 serine-58. Our results suggest that the release of DISC1-mediated transcriptional repression of PDE4D9 acts as feedback inhibition to regulate dopaminergic signaling. Furthermore, as DISC1 loss-of-function leads to a specific increase in PDE4D9, PDE4D9 itself may represent an attractive target for therapeutic approaches in psychiatric disorders.National Institute of General Medical Sciences (U.S.) (Award T32GM07753)National Institutes of Health (U.S.) (R01 MH091115

Experimental characterization of turbulence spots on a flat plate at Mach 6

Transition modelling and prediction is a critical topic at hypersonic speeds because of the physically large extent of the transition region and the impact of large variations or uncertainties in heat transfer, skin friction and other flow properties. The experimental activity presented in this paper is concerned with the intermittent region of transition, which extends from the initial breakdown of the laminar layer into turbulent ‘spots’ up to the position where the boundary layer is fully turbulent. The turbulent spots and roughness induced transition are strongly affected by compressibility and wall temperature.To improve the quantitative understanding of these effects direct and large-eddy simulations can be performed for prescribed surface characteristics. The simulation output will provide details of boundary layer intermittency, heat transfer and skin friction for comparison with dedicated experiments conducted in an high-speed wind tunnel.The paper will presents the results of the simulations and the first set of experiment carried out in the framework of the ATLLAS project, for a flight configuration at Mach 6. A brief critical discussion of the results will also be presented

MHD blunt body test design in high enthalpy plasma air flow

This paper deals with the design of an experiment devoted to MHD flow control, to be performed in CIRA GHIBLI hypersonic facility. The aim of this work is to define the proper test conditions and to design and realize the model that will be tested in the facility. Numerical simulations have been carried out in order to have a preliminary estimate of the ionization degree and of the heat fluxes over the test article. Moreover the MFD code from Bologna University has been used in order to calculate the expected interaction effect, under the assumption of low Rem. Finally, the design of the test article has been carried out

Loss of Toll-like receptor 7 alters cytokine production and protects against experimental cerebral malaria

© 2014 Baccarella et al.; licensee BioMed Central Ltd.Background: Malaria, caused by Plasmodium sp. parasites, is a leading cause of global morbidity and mortality. Cerebral malaria, characterized by neurological symptoms, is a life-threatening complicati