448 research outputs found
UV Emission line shifts of symbiotic binaries
Relative and absolute emission line shifts have been previously found for
symbiotic binaries, but their cause was not clear. This work aims to better
understand the emission line shifts. Positions of strong emission lines were
measured on archival UV spectra of Z And, AG Dra, RW Hya, SY Mus and AX Per and
relative shifts between the lines of different ions compared. Profiles of lines
of RW Hya and Z And were also examined. The reality of the relative shift
between resonance and intercombination lines of several times ionised atoms was
clearly shown except for AG Dra. This redshift shows a well defined variation
with orbital phase for Z And and RW Hya. In addition the intercombination lines
from more ionised atoms and especially OIV are redshifted with respect to those
from less ionised atoms. Other effects are seen in the profiles. The
resonance-intercombination line shift variation can be explained in quiescence
by P Cygni shorter wavelength component absorption, due to the wind of the cool
component, which is specially strong in inferior conjunction of this cool
giant. The velocity stratification permits absorption of line emission. The
relative intercombination line shifts may be connected with varying occultation
of line emission near an accretion disk, which is optically thick in the
continuum.Comment: 14 pages, 11 figures, to appear in A&
Low creep and hysteresis silicon load cell based on a force-to-liquid pressure transformation
Important problems in load cells are creep and hysteresis. Expensive high grade steels are used in order to reduce these effects. In this paper a silicon load cell design is presented which is based on a force-to-liquid-pressure transformation. The design is insensitive to hysteresis and creep, can be made at very low costs and is able to measure loads up to 1000 kg with an accuracy of 0.03 %. Analytical, numerical and experimental results on a macroscopic steel load cell are in very close agreement with each other
A differential resonator design using a bossed structure for applications in mechanical sensors
Theory and experimental results are presented of a differential resonator design employing a bossed structure for applications in mechanical sensors. The effects of residual strain, temperature and mechanical load on the resonance frequency are investigated. Mismatches in the resonators are accounted for in the analysis, resulting in a predicted temperature dependence of the offset and of the sensitivity. Experimental data obtained from a macroscopic brass model, mounted on a steel bar and applied as a force sensor, are given. Compared to a design employing a single resonator, the measurements indicate a doubling in force sensitivity and a reduction of both the intrinsic temperature dependence and of the differential thermal expansion effects. The results of this research are directly applicable to micromachined structures in silicon
Micromachined capacitive long-range displacement sensor
First measurement results are presented for a surface-micromachined long-range (50– 100 μm) periodic capacitive position sensor. The sensor consists of two periodic geometries (period = 10 μm) sliding along each other with minimum spacing of about 1.5 μm. The relative displacement between the two, results in a periodic change in capacitance. An electrostatic comb-drive actuator is employed to generate displacements. Measured maximum capacitance change ΔC=0.72 fF corresponds to simulation results but needs better shielding from external noise sources. The results show this sensorconcept can potentially lead towards long-range nano-positioning control of microactuator systems
Development of a Capacitive Mems RF Power Sensor Without Dissipative Losses: Towards a New Philosophy of RF Power Sensing
The development of a novel radio frequency (RF) power sensor is presented based on capacitive micro electromechanical system (MEMS) technology, in which the signal is barely disturbed during the power measurement. Results of the first prototypes and improvements for the second generation of RF power sensors are given\ud
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Micromachined capacitive displacement sensor for long-range nano-positioning
Integrated long-range position sensing with high accuracy will be of paramount importance for high-potential applications in a.o. future probe-based datastorage and microscopy applications [1], provided that nm position accuracy can be obtained over a range of tens of micrometers or more. This work presents the design, fabrication and measurements for an integrated incremental capacitive long-range position sensor for nano-positioning of microactuators. For compactness, economical viability and optimal performance, the aim has been to fully integrate sensor and actuator through micromachining technology, without additional micro-assembly. Two related concepts are presented and evaluated through analysis, 2D-Finite-Element Simulations and experimental assessment. The sensors consist of two periodic geometries (period ≈ 8-16μm) on resp. a slider, movable in x-direction, and sense-structures, movable in y-direction, at both sides of the slider, Fig. 1. In ICMM the displacement of the slider is measured by measuring the periodic change in capacitance ΔCs(x) with a charge-amplifier and synchronous detection technique [2]. Using sense-actuators, the gap-distance between sense-structures and slider is made smaller than is possible with standard available photo-lithography (< 2 μm), thus increasing the capacitance and the S-N Ratio
Radio frequency power sensor based on MEMS technology
We present the first measurement results of a power sensor for radio frequency (rf) signals (50 kHz - 40 GHz) with almost no dissipation during the measurement. This sensor is, therefore, a 'through' power sensor, that means that the rf signal is available during the measurement of its power. The power detection has been realized by measuring capacitively the movement of a grounded aluminum membrane, which is suspended above the transmission line carrying the rf signal. The power sensor is thus a capacitive MEMS technology based sensor. The fabrication is done by aluminum surface micromachining on an AF45 glass wafer. We measured the capacitance as a function of the applied rf power and found a linear relationship as predicted from theory
CD8+ cell somatic mutations in multiple sclerosis patients and controls-Enrichment of mutations in STAT3 and other genes implicated in hematological malignancies
Funding Information: This study has been financially supported by research grants from the Helsinki University Hospital, University of Helsinki, the Multiple Sclerosis Foundation of Finland, the Finnish Cultural Foundation, Biogen Finland, Sanofi- Genzyme, Roche and Novartis. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Publisher Copyright: © 2021 Valori et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Somatic mutations have a central role in cancer but their role in other diseases such as common autoimmune disorders is not clear. Previously we and others have demonstrated that especially CD8+ T cells in blood can harbor persistent somatic mutations in some patients with multiple sclerosis (MS) and rheumatoid arthritis. Here we concentrated on CD8+ cells in more detail and tested (i) how commonly somatic mutations are detectable, (ii) does the overall mutation load differ between MS patients and controls, and (iii) do the somatic mutations accumulate non-randomly in certain genes? We separated peripheral blood CD8+ cells from newly diagnosed relapsing MS patients (n = 21) as well as matched controls (n = 21) and performed next-generation sequencing of the CD8+ cells' DNA, limiting our search to a custom panel of 2524 immunity and cancer related genes, which enabled us to obtain a median sequencing depth of over 2000x. We discovered nonsynonymous somatic mutations in all MS patients' and controls' CD8+ cell DNA samples, with no significant difference in number between the groups (p = 0.60), at a median allelic fraction of 0.5% (range 0.2- 8.6%). The mutations showed statistically significant clustering especially to the STAT3 gene, and also enrichment to the SMARCA2, DNMT3A, SOCS1 and PPP3CA genes. Known activating STAT3 mutations were found both in MS patients and controls and overall 1/5 of the mutations were previously described cancer mutations. The detected clustering suggests a selection advantage of the mutated CD8+ clones and calls for further research on possible phenotypic effects.Peer reviewe
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