310 research outputs found
Cyclic loading is harmful to articular cartilage from which proteoglycans have been partially depleted by retinoic acid
SummaryWe studied whether cyclic loading is harmful to degraded cartilage. Sets of four cartilage-bearing sesamoid bones were dissected from 5-year-old cows. One bone from each set was cultured for 17 h in control medium to serve as an ex vivo control. The three others were cultured for 1 week in control medium to which 0, 10 or 300 ng/ml retinoic acid (RAc), which depletes the cartilage matrix of proteoglycans, had been added. Two were then cultured for another week in control medium. During the last week, one of the two was subjected to a cyclic load (1 MPa, 0.2 Hz). Following treatment with RAc, glycosaminoglycan content and synthesis were significantly decreased, as confirmed by safranin O staining and autoradiography. They were further diminished by loading during the second week of culture. Increased amounts of 3-B-3(â) epitope were found in cartilage that had been treated with 300 ng/ml RAc and then loaded. While loading cartilage matrix that was only slightly degraded proved to be damaging, loading severely degraded cartilage matrix apparently induced osteoarthritic-like changes
Different properties of ACPA and IgM-RF derived from a large dataset: further evidence of two distinct autoantibody systems
Superconducting resonator circuits at frequencies above the gap frequency
The frequency response of three superconductive niobium resonating circuits, formed by a Nb microstrip and a Nb tunnel junction, is measured and analyzed at frequencies above the superconducting gap frequency. The circuits are placed in a waveguide system and the frequency response is determined with a Fourier transform spectrometer. The calculated and measured resonance frequencies and bandwidths are in good agreement with the extreme anomalous limit of the MattisâBardeen theory on the anomalous skin effect in superconductors [D.C. Mattis and J. Bardeen, Phys. Rev. 111, 412 (1958)]. The observed loss is higher than predicted by this theory, in agreement with previous observations on Nb films. The use of other materials for striplines as tuning circuits for heterodyne superconducting tunnel junction mixers is analyzed
The value of ultrasonography in predicting arthritis in auto-antibody positive arthralgia patients: a prospective cohort study
Antibodies to mutated citrullinated vimentin and disease activity score in early arthritis: a cohort study
Symptom complexes in patients with seropositive arthralgia and in patients newly diagnosed with rheumatoid arthritis: a qualitative exploration of symptom development
Objective: The aim of this study was to explore symptoms and symptom development during the earliest phases of rheumatoid arthritis (RA) in patients with seropositive arthralgia and patients newly diagnosed with RA
Efficient light coupling into a photonic crystal waveguide with flatband slow mode
We design an efficient coupler to transmit light from a strip waveguide into
the flatband slow mode of a photonic crystal waveguide with ring-shaped holes.
The coupler is a section of a photonic crystal waveguide with a higher group
velocity, obtained by different ring dimensions. We demonstrate coupling
efficiency in excess of 95% over the 8 nm wavelength range where the photonic
crystal waveguide exhibits a quasi constant group velocity vg = c/37. An
analysis based on the small Fabry-P\'erot resonances in the simulated
transmission spectra is introduced and used for studying the effect of the
coupler length and for evaluating the coupling efficiency in different parts of
the coupler. The mode conversion efficiency within the coupler is more than
99.7% over the wavelength range of interest. The parasitic reflectance in the
coupler, which depends on the propagation constant mismatch between the slow
mode and the coupler mode, is lower than 0.6% within this wavelength range.Comment: 11 pages, 7 figures, submitted to Photonics and Nanostructures -
Fundamentals and Application
Anomalous spin-splitting of two-dimensional electrons in an AlAs Quantum Well
We measure the effective Lande g-factor of high-mobility two-dimensional
electrons in a modulation-doped AlAs quantum well by tilting the sample in a
magnetic field and monitoring the evolution of the magnetoresistance
oscillations. The data reveal that |g| = 9.0, which is much enhanced with
respect to the reported bulk value of 1.9. Surprisingly, in a large range of
magnetic field and Landau level fillings, the value of the enhanced g-factor
appears to be constant.Comment: 4 pages, 3 figure
T cell subsets: An immunological biomarker to predict progression to clinical arthritis in ACPA-positive individuals
Objectives Anticitrullinated protein antibody (ACPA)+ individuals with non-specific musculoskeletal symptoms are at risk of inflammatory arthritis (IA). This study aims to demonstrate the predictive value of T cell subset quantification for progression towards IA and compare it with previously identified clinical predictors of progression. Methods 103 ACPA+ individuals without clinical synovitis were observed 3-monthly for 12 months and then as clinically indicated. The end point was the development of IA. NaĂŻve, regulatory T cells (Treg) and inflammation related cells (IRCs) were quantified by flow cytometry. Areas under the ROC curve (AUC) were calculated. Adjusted logistic regressions and Cox proportional hazards models for time to progression to IA were constructed. Results Compared with healthy controls (age adjusted where appropriate), ACPA+ individuals demonstrated reduced naĂŻve (22.1% of subjects) and Treg (35.8%) frequencies and elevated IRC (29.5%). Of the 103 subjects, 48(46.6%) progressed. Individually, T cell subsets were weakly predictive (AUC between 0.63 and 0.66), although the presence of 2 T cell abnormalities had high specificity. Three models were compared: model-1 used T cell subsets only, model-2 used previously published clinical parameters, model-3 combined clinical data and T cell data. Model-3 performed the best (AUC 0.79 (95% CI 0.70 to 0.89)) compared with model-1 (0.75 (0.65 to 0.86)) and particularly with model-2 (0.62 (0.54 to 0.76)) demonstrating the added value of T cell subsets. Time to progression differed significantly between high-risk, moderate-risk and low-risk groups from model-3 (p=0.001, median 15.4 months, 25.8 months and 63.4 months, respectively). Conclusions T cell subset dysregulation in ACPA+ individuals predates the onset of IA, predicts the risk and faster progression to IA, with added value over previously published clinical predictors of progression
The acâJosephson effect above the gap frequency
The rfâpower dependence of the acâJosephson steps is measured at 720 GHz, using small area Nb tunnel junctions. This frequency is well above the gap frequency of Nb. The junction is placed in a waveguide, and connected to a superconducting stripline, which effectively tunes out the junction capacitance and facilitates the coupling of the radiation to the junction. We observe three Josephson steps, and the first step crosses the zero current axis over a considerable range of rfâpower. This indicates the possible application of THz Josephson steps in voltage standards. The data are compared to the theory and we find clear evidence for the predicted intrinsic rollâoff of the Josephson current amplitude above the gap frequency
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