1,114 research outputs found
Performance and loads data from an outdoor hover test of a Lynx tail rotor
A Lynx tail rotor was tested in hover at the Outdoor Aerodynamic Research Facility at NASA Ames Research Center. The test objectives were to measure the isolated rotor performance to provide a baseline for subsequent testing, and to operate the rotor throughout the speed and collective envelope before testing in the NFAC 40- by 80-Foot Wind Tunnel. Rotor forces and blade bending moments were measured at ambient wind conditions from zero to 6.23 m/sec. The test envelope was limited to rotor speeds of 1550 to 1850 rpm and minus 13 deg to plus 20 deg of blade collective pitch. The isolated rotor performance and blade loads data are presented
BMP2 and TGF-β Cooperate Differently during Synovial-Derived Stem-Cell Chondrogenesis in a Dexamethasone-Dependent Manner
Recent studies highlighting mesenchymal stem cell (MSC) epigenetic memory suggest that a different differentiation medium may be required depending on the tissue of origin. As synovial-derived stem cells (SDSCs) attract interest we aimed to investigate the influence of TGF-β1, BMP-2 and dexamethasone on SDSC chondrogenesis in vitro. We demonstrate that dexamethasone-free medium led to enhanced chondrogenic differentiation at both the mRNA and matrix level. The greatest COL2A1/COL10A1 ratio was detected in cells exposed to a combination medium containing 10 ng/mL BMP-2 and 1 ng/mL TGF-β1 in the absence of dexamethasone, and this was reflected in the total amount of glycosaminoglycans produced. In summary, dexamethasone-free medium containing BMP-2 and TGF-β1 may be the most suitable when using SDSCs for cartilage tissue regeneration
Budget processes : theory and experimental evidence
This paper studies budget processes, both theoretically and experimentally. We give a sufficient condition for top-down and bottom-up budget processes to have the same voting equilibrium. Furthermore, at a voting equilibrium, it is not always true, as often presumed, that a top-down budget process leads to a smaller overall budget than does a bottom-up budget process. To test the implications for budget processes of voting equilibrium theory, we conduct a series of 128 voting experiments using subjects in a behavior laboratory. The experimental evidence from these experiments is well organized by voting equilibrium theory, both at the aggregate level and at the individual subject level. In particular, subjects display considerable evidence of rationality in their proposals and votes. More complete information and fewer spending categories lead to greater predictive success of voting equilibrium theory, and reduce the time needed to reach a budget decision
Budget Processes: Theory and Experimental Evidence
This paper studies budget processes, both theoretically and experimentally. We compare the outcomes of bottom-up and top-down budget processes. It is often presumed that a top-down budget process leads to a smaller overall budget than a bottom-up budget process. Ferejohn and Krehbiel (1987) showed theoretically that this need not be the case. We test experimentally the theoretical predictions of their work. The evidence from these experiments lends strong support to their theory, both at the aggregate and the individual subject level
The SOUX AGN sample: optical/UV/X-ray SEDs and the nature of the disc
We use the SOUX sample of ∼700 active galactic nucleus (AGN) to form average optical-ultraviolet (UV)-X-rays spectral energy distributions (SEDs) on a two-dimensional (2D) grid of MBH and L2500. We compare these with the predictions of a new AGN SED model, QSOSED, which includes prescriptions for both hot and warm Comptonization regions as well as an outer standard disc. This predicts the overall SED fairly well for 7.5 < log(MBH/M⊙) < 9.0 over a wide range in L/LEdd, but at higher masses the outer disc spectra in the model are far too cool to match the data. We create optical-UV composites from the entire Sloan Digital Sky Survey sample and use these to show that the mismatch is due to there being no significant change in spectral shape of the optical-UV continuum across several decades of MBH at constant luminosity. We show for the first time that this cannot be matched by standard disc models with high black hole spin. These apparently fit, but are not self-consistent as they do not include the General Relativistic effects for the emission to reach the observer. At high spin, increased gravitational redshift compensates for almost all of the higher temperature emission from the smaller inner disc radii. The data do not match the predictions made by any current accretion flow model. Either the disc is completely covered by a warm Comptonization layer whose properties change systematically with L/LEdd, or the accretion flow structure is fundamentally different to that of the standard disc models
Flux flow resistivity and vortex viscosity of high-Tc films
The flux flow regime of high-T samples of different normal state
resistivities is studied in the temperature range where the sign of the Hall
effect is reversed. The scaling of the vortex viscosity with normal state
resistivity is consistent with the Bardeen-Stephen theory. Estimates of the
influence of possible mechanisms suggested for the sign reversal of the Hall
effect are also given.Comment: 3 pages. 4 figures upon reques
Schottky-based band lineups for refractory semiconductors
An overview is presented of band alignments for small-lattice parameter, refractory semiconductors. The band alignments are estimated empirically through the use of available Schottky barrier height data, and are compared to theoretically predicted values. Results for tetrahedrally bonded semiconductors with lattice constant values in the range from C through ZnSe are presented. Based on the estimated band alignments and the recently demonstrated p-type dopability of GaN, we propose three novel heterojunction schemes which seek to address inherent difficulties in doping or electrical contact to wide-gap semiconductors such as ZnO, ZnSe, and ZnS
An inflammatory condition with different faces: Immunoglobulin G4-Related disease
__Background:__ Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition with involvement of different organs. The pathophysiological mechanism is unclear, but fibrosis is the hallmark of this disease. Early recognition is critical to avoid irreversible organ damage. Recently improved histological testing boosts the diagnostic yield. We present three cases of patients with IgG4-RD to emphasise the broad clinical presentation of this disease.
__Case descriptions:__ Patient A, a 63-year-old male with bilateral orbital swelling due to IgG4-RD, was shown to suffer from IgG4-RD in a multifocal pattern as demonstrated by PET scanning. Patient B, a 53-year-old male with a long-standing abdominal mass of unknown origin, eventually proved to have IgG4-RD. Patient C was a 32-year-old male admitted with pleural effusion and pericardial tamponade. Histological diagnosis after pericardiectomy confirmed IgG4-RD.
__Discussion:__ IgG4-RD has many faces and may mimic other conditions, such as malignancy and infectious diseases. Knowledge of this disease is needed to avoid unnecessary diagnostics and delay in treatment. IgG4-RD may be suspected based on specific clinical findings such as elevated serum IgG4 levels, but the diagnosis can only be established histologically. Although corticosteroids are an effective first choice of therapy, the relapse rate after this treatment remains high. The role of disease-modifying antirheumatic drugs in the treatment of IgG4-RD has not been outlined yet, but there is increasing evidence that rituximab might be an effective second-line therapy.
__Conclusion:__ IgG4-RD is a disease with many faces requiring early recognition and therapy to avoid permanent damage of the organs
Biologic Therapy for HLA-B27-associated Ocular Disorders
The treatment of articular and extra-articular manifestations associated with HLA-B27 has undergone dramatic changes over the past two decades, mainly as a consequence of the introduction of biologic agents and in particular anti-tumor necrosis factor α (anti-TNFα) agents. Uveitis is known to be the most frequent extra-articular feature in HLA-B27-associated spondyloarthritides. Topical corticosteroids and cycloplegic agents remain the cornerstones of treatment. However, biologic therapy may be effective in the management of refractory or recurrent forms of uveitis. This review gives an update on the management of HLA-B27-associated ocular disorders with biologics, including anti-TNFα agents and non-anti-TNFα biologic modifier drugs. There is an emerging role for newer biologics targeting interleukin-12/23 and interleukin-17 for the treatment of spondyloarthritides but data on their efficacy on anterior uveitis are sparse
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