108 research outputs found
Propulsion simulation for magnetically suspended wind tunnel models
The feasibility of simulating propulsion-induced aerodynamic effects on scaled aircraft models in wind tunnels employing Magnetic Suspension and Balance Systems. The investigation concerned itself with techniques of generating exhaust jets of appropriate characteristics. The objectives were to: (1) define thrust and mass flow requirements of jets; (2) evaluate techniques for generating propulsive gas within volume limitations imposed by magnetically-suspended models; (3) conduct simple diagnostic experiments for techniques involving new concepts; and (4) recommend experiments for demonstration of propulsion simulation techniques. Various techniques of generating exhaust jets of appropriate characteristics were evaluated on scaled aircraft models in wind tunnels with MSBS. Four concepts of remotely-operated propulsion simulators were examined. Three conceptual designs involving innovative adaptation of convenient technologies (compressed gas cylinders, liquid, and solid propellants) were developed. The fourth innovative concept, namely, the laser-assisted thruster, which can potentially simulate both inlet and exhaust flows, was found to require very high power levels for small thrust levels
The `Friction' of Vacuum, and other Fluctuation-Induced Forces
The static Casimir effect describes an attractive force between two
conducting plates, due to quantum fluctuations of the electromagnetic (EM)
field in the intervening space. {\it Thermal fluctuations} of correlated fluids
(such as critical mixtures, super-fluids, liquid crystals, or electrolytes) are
also modified by the boundaries, resulting in finite-size corrections at
criticality, and additional forces that effect wetting and layering phenomena.
Modified fluctuations of the EM field can also account for the `van der Waals'
interaction between conducting spheres, and have analogs in the
fluctuation--induced interactions between inclusions on a membrane. We employ a
path integral formalism to study these phenomena for boundaries of arbitrary
shape. This allows us to examine the many unexpected phenomena of the dynamic
Casimir effect due to moving boundaries. With the inclusion of quantum
fluctuations, the EM vacuum behaves essentially as a complex fluid, and
modifies the motion of objects through it. In particular, from the mechanical
response function of the EM vacuum, we extract a plethora of interesting
results, the most notable being: (i) The effective mass of a plate depends on
its shape, and becomes anisotropic. (ii) There is dissipation and damping of
the motion, again dependent upon shape and direction of motion, due to emission
of photons. (iii) There is a continuous spectrum of resonant cavity modes that
can be excited by the motion of the (neutral) boundaries.Comment: RevTex, 2 ps figures included. The presentation is completely
revised, and new sections are adde
Consensus Recommendations for Histological Criteria of Autoimmune Hepatitis from the International AIH Pathology Group
Background & Aims Diagnostic histological criteria for autoimmune hepatitis (AIH) have not been clearly established. Previously published criteria focused mainly on chronic AIH, in which inflammatory changes mainly occur in portal/periportal regions and may not be applicable to acute presentation of AIH, in which inflammatory changes are typically predominantly lobular in location. International consensus criteria for the diagnosis and assessment of disease severity in both acute and chronic AIH are thus urgently needed. Methods Seventeen expert liver pathologists convened at an international workshop and subsequently used a modified Delphi panel approach to establish consensus criteria for the histopathological diagnosis of AIH. Results The consensus view is that liver biopsy should remain standard for diagnosing AIH. AIH is considered likely, if there is a predominantly portal lymphoplasmacytic hepatitis with more than mild interface activity and/or more than mild lobular hepatitis in the absence of histological features suggestive of another liver disease. AIH is also considered likely if there is predominantly lobular hepatitis with or without centrilobular necroinflammation and at least one of the following features: portal lymphoplasmacytic hepatitis, interface hepatitis or portal-based fibrosis, in the absence of histological features suggestive of another liver disease. Emperipolesis and hepatocellular rosettes are not regarded as being specific for AIH. Conclusions The criteria proposed in this consensus statement provide a uniform approach to the histological diagnosis of AIH, which is relevant for patients with an acute as well as a chronic presentation and to more accurately reflect the current understanding of liver pathology in AIH
Eros is a novel transmembrane protein that controls the phagocyte respiratory burst and is essential for innate immunity
The phagocyte respiratory burst is crucial for innate immunity. The transfer of electrons to oxygen is mediated by a membrane-bound heterodimer, comprising gp91 and p22 subunits. Deficiency of either subunit leads to severe immunodeficiency. We describe Eros (essential for reactive oxygen species), a protein encoded by the previously undefined mouse gene , and show that it is essential for host defense via the phagocyte NAPDH oxidase. Eros is required for expression of the NADPH oxidase components, gp91 and p22. Consequently, -deficient mice quickly succumb to infection. also contributes to the formation of neutrophil extracellular traps (NETS) and impacts on the immune response to melanoma metastases. is an ortholog of the plant protein Ycf4, which is necessary for expression of proteins of the photosynthetic photosystem 1 complex, itself also an NADPH oxio-reductase. We thus describe the key role of the previously uncharacterized protein Eros in host defense.D.C. Thomas was funded by a Wellcome Trust/CIMR Next Generation Fellowship, a National Institute for Health Research (NIHR) Clinical Lectureship, and a Starter Grant for Clinical Lecturers (Academy of Medical Sciences). K.G.C. Smith was funded by funded by the Medical Research Council (program grant MR/L019027) and is a Wellcome Investigator and a NIHR Senior Investigator. S. Clare and G. Dougan were funded by the Wellcome Trust (grant 098051). The Cambridge Institute for Medical Research is in receipt of a Wellcome Trust Strategic Award (079895). J.C.L is funded by a Wellcome Intermediate Clinical Fellowship 105920/2/14/2
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