Open Rotor Development

The ERA project executed a comprehensive test program for Open Rotor aerodynamic and acoustic performance. System studies used the data to estimate the fuel burn savings and acoustic margin for an aircraft system with open rotor propulsion. The acoustic measurements were used to produce an auralization that compares the legacy blades to the current generation of open rotor designs

Influence of tip clearance on flow behavior and noise generation of centrifugal compressors in near-surge conditions

CFD has become an essential tool for researchers to analyze centrifugal compressors. Tip leakage flow is usually considered one of the main mechanisms that dictate compressor flow field and stability. However, it is a common practice to rely on CAD tip clearance, even though the gap between blades and shroud changes when compressor is running. In this paper, sensitivity of centrifugal compressor flow field and noise prediction to tip clearance ratio is investigated. 3D CFD simulations are performed with three different tip clearance ratios in accordance to expected operating values, extracted from shaft motion measurements and FEM predictions of temperature and rotational deformation. Near-surge operating conditions are simulated with URANS and DES. DES shows superior performance for acoustic predictions. Cases with reduced tip clearance present higher pressure ratio and isentropic efficiency, but no significant changes in compressor acoustic signature are found when varying clearance. In this working point, tip clearance is immersed in a region of strongly swirling backflow. Therefore, tip leakage cannot establish any coherent noise source mechanism.The equipment used in this work has been partially supported by FEDER project funds "Dotacion de infraestructuras cientifico tecnicas para el Centro Integral de Mejora Energetica y Medioambiental de Sistemas de Transporte (CiMeT), (FEDER-ICTS-2012-06)", framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain. The authors wish to thank Mr. Pau Raga for his worthy assistance during the meshing process.Galindo, J.; Tiseira Izaguirre, AO.; Navarro García, R.; López Hidalgo, MA. (2015). Influence of tip clearance on flow behavior and noise generation of centrifugal compressors in near-surge conditions. International Journal of Heat and Fluid Flow. 52:129-139. https://doi.org/10.1016/j.ijheatfluidflow.2014.12.004S1291395

Extracellular Sulfatases, Elements of the Wnt Signaling Pathway, Positively Regulate Growth and Tumorigenicity of Human Pancreatic Cancer Cells

BACKGROUND: Heparan sulfate proteoglycans (HSPGs) are control elements in Wnt signaling, which bind extracellularly to Wnt ligands and regulate their ability to interact with signal transduction receptors on the cell surface. Sulf-1 and Sulf-2 are novel extracellular sulfatases that act on internal glucosamine-6-sulfate (6S) modifications within HSPGs and thereby modulate HSPG interactions with various signaling molecules, including Wnt ligands. Emerging evidence indicates the importance of reactivated Wnt signaling in a number of cancers, including pancreatic adenocarcinoma. PRINCIPLE FINDINGS: Both Sulf proteins were upregulated in human pancreatic adenocarcinoma tumors and were broadly expressed in human pancreatic adenocarcinoma cell lines. Expression of human extracellular sulfatases Sulf-1 and Sulf-2 enhanced Wnt signaling in a reconstituted system. Three of four pancreatic adenocarcinoma cell lines tested exhibited autocrine Wnt signaling, in that extracellular Wnt ligands were required to initiate downstream Wnt signaling. Exposure of these pancreatic adenocarcinoma cells to a catalytically inactive form of Sulf-2 or siRNA-mediated silencing of endogenous Sulf-2 inhibited both Wnt signaling and cell growth. Sulf-2 silencing in two of these lines resulted in markedly reduced tumorigenesis in immunocompromised mice. CONCLUSIONS/SIGNIFICANCE: We have identified the Sulfs as potentiators of autocrine Wnt signaling in pancreatic cancer cells and have demonstrated their contribution to the growth and tumorigenicity of these cells. Since the Sulfs are extracellular enzymes, they would be attractive targets for therapy of pancreatic cancer. Our results run counter to the prevailing view in the literature that the Sulfs are negative regulators of tumorigenesis

Ossification of the Vascular Pedicle in Microsurgical Fibular Free Flap Reconstruction of the Head and Neck

Background and purposeThe fibular free flap, often used for osseous reconstruction following extirpation of head and neck malignancies, has been associated with heterotopic periosteal ossification. We aimed to determine the frequency and radiologic characteristics of this process and describe its clinical correlates.Materials and methodsSurgical records for 2 years and neck imaging reports for 10 years were evaluated to identify patients with fibular free flap reconstruction and CT and/or PET/CT imaging available for review. The images were evaluated for the quality, type, and contour of ossification, and the reports were reviewed for associated clinical findings and radiologic impressions.ResultsOf 32 patients with posttreatment CT or PET/CT imaging, ossification was evident in 16 patients (50%) as early as 1 month following fibular free flap reconstruction. In 8 patients, it mimicked a new bone; in 5, it appeared as linear attenuation; in 2, as multiple short segments; and in 1 patient, a mixed appearance was found. No associated FDG uptake was seen on PET/CT. On MR imaging, these findings were extremely subtle or not appreciable. In only 1 patient was new bone associated with symptoms.ConclusionsPeriosteal ossification of the vascular pedicle is commonly evident on CT following fibular free flap, even as early as 1 month after reconstruction, though the finding is not typically noted on imaging. While symptoms related to new bone are uncommon, they may mimic recurrent tumor. The location and pattern of ossification and the absence of a soft-tissue mass or FDG uptake are useful distinguishing imaging features

Fatal cerebral oedema in adult diabetic ketoacidosis.

Item does not contain fulltextIn this report, a case of adult onset fatal cerebral oedema as a rare complication of diabetic ketoacidosis (DKA) is described and confirmed at post-mortem pathological examination. The pathogenesis of cerebral oedema due to DKA is still unknown. Potential mechanisms include the administration of sodium bicarbonate leading to intracellular acidosis, excessive fluid infusion causing swelling of brain tissue, or reduction of plasma osmolarity by a rapid fall in glucose levels causing osmotic swelling.1 januari 201