1,456 research outputs found
Neumann-Hoffman Code Evasion and Stripping Method for BeiDou Software-defined Receiver
© 2016 The Royal Institute of Navigation. The acquisition and tracking strategies of the BeiDou navigation satellite signals are affected by the modulation of Neumann-Hoffman code (NH code), which increases the complexity of receiver baseband signal processing. Based on the analysis of probability statistics of the NH code, a special sequence of incoming signals is proposed to evade the bit transitions caused by the NH code, and an NH Code Evasion and Stripping method (NCES) based on the NH-pre-modulated code is proposed. The NCES can be applied in both 20-bit NH code and 10-bit NH code. The fine acquisition eliminates the impact of NH code on the traditional tracking loop. These methods were verified with a BeiDou PC-based software-defined receiver using the actual sampled signals. Compared with other acquisition schemes which try to determine or ignore the NH code phase, the NCES needs fewer incoming signals and the actual runtime is greatly reduced without sacrificing much time to search in the secondary code dimension, and the success rate of acquisition is effectively improved. An extension of Fast Fourier Transform (FFT)-based parallel code-phase search acquisition gives the NCES an advantage in engineering applications
FABP7 (fatty acid binding protein 7, brain)
Review on FABP7, with data on DNA/RNA, on the protein encoded and where the gene is implicated
Kinematic modelling of a 3-axis NC machine tool in linear and circular interpolation
Machining time is a major performance criterion when it comes to high-speed
machining. CAM software can help in estimating that time for a given strategy.
But in practice, CAM-programmed feed rates are rarely achieved, especially
where complex surface finishing is concerned. This means that machining time
forecasts are often more than one step removed from reality. The reason behind
this is that CAM routines do not take either the dynamic performances of the
machines or their specific machining tolerances into account. The present
article seeks to improve simulation of high-speed NC machine dynamic behaviour
and machining time prediction, offering two models. The first contributes
through enhanced simulation of three-axis paths in linear and circular
interpolation, taking high-speed machine accelerations and jerks into account.
The second model allows transition passages between blocks to be integrated in
the simulation by adding in a polynomial transition path that caters for the
true machining environment tolerances. Models are based on respect for path
monitoring. Experimental validation shows the contribution of polynomial
modelling of the transition passage due to the absence of a leap in
acceleration. Simulation error on the machining time prediction remains below
1%
Role of CD56-expressing immature biliary epithelial cells in biliary atresia
published_or_final_versio
Analysis of Kif5b Expression during Mouse Kidney Development
published_or_final_versio
Determination of trace amounts of gold(III) by cathodic stripping voltammetry using a bacteria-modified carbon paste electrode
A bacteria-modified carbon paste electrode has been prepared and used for the very sensitive and selective determination of trace amounts of gold(III). The modified electrode was able to detect a solution of 1.0 ppb Au(III) by applying cathodic stripping voltammetry. Advantages of the bacteria-modified electrode include high sensitivity, good stability, low cost and simple preparation. It could be a new class of modified electrode with practical value
Metamorphism and geochronology of the spinelâcordierite granulite in the Mirror Peninsula, East Antarctica
Objective  The Prydz Bay belt in East Antarctica recorded two significant tectono-thermal events, the Grenvillian event and the Pan-African event, which are considered to be closely related to the evolution of the Rodinia and Gondwana supercontinents. However, the geological history and the tectonic nature of the two events remain controversial.  Methods  Mineralogical and petrological analyses, phase equilibria modelling and zircon geochronology are combined to investigate the spinelâcordierite granulite from the Mirror Peninsula in order to better understand the tectono-thermal history of the Prydz Bay belt.  Results  The spinelâcordierite granulite contains different stages of mineral assemblages. The major stage of mineral assemblage involves cordierite, spinel, biotite, sillimanite, K-feldspar and minor garnet and ilmenite. The later stage of mineral assemblage is indicated by the emergence of magnetite as the increasing volumes of biotite and cordierite. Minor garnet and corundum are locally preserved, implying the mineral reaction âg+corâsp+sillâ and more garnet and corundum in the peak stage. The garnet grains consist of 70%â72% almandine, 20%â22% pyrope, ~4% grossularite and ~4% spessartine. The XFe (Fe2+/(Fe2++Mg2+)) of representative garnet grains ranges from 0.77 to 0.80. The spinel exhibits an XFe range from 0.80 to 0.86. Different cordierite grains have similar compositions with Al of 3.89â3.93 a.p.f.u (atoms per formula unit) and XFe of 0.32â0.36. Biotite has high TiO2 (4.13%â5.23%) and Ti (0.23â0.30 a.p.f.u). K-feldspar grains consist of 78%â85% orthoclase, 15%â23% albite and ~1% anorthite. Based on the mineral compositions and phase equilibrium modelling, the pressureâtemperature (PâT) conditions of the major stage of mineral assemblage are constrained to 870â910 °C and 0.64â0.69 GPa, followed by later retrogression to 810â820°C and 0.49â0.53 GPa. A peak stage with higher PâT conditions (T>910 â, P>0.69 GPa) can be inferred based on the relict peak minerals and characteristic mineral compositions (e.g. Ti in biotite). Zircon grains commonly show core-mantle-rim structures in cathodoluminescence (CL) images. The LAâICPâMS zircon UâPb dating analyses reveal a wide age range from 613±7 Ma to 877±9 Ma (except a maximum of 916±11 Ma) for the cores. The zircon bright rims yield a weighted mean age of 526±8 Ma with a wide range of Th/U (0.06â1.23), mostly higher than 0.1.  Conclusion  Based on the results, a few conclusions can be drawn: (1) The spinelâcordierite granulite recorded mediumâlow pressure/high-ultrahigh temperature metamorphism with a clockwise PâT evolution path and high dT/dP. (2) The results of zircon geochronological analysis show that zircon cores mainly record UâPb ages in the range of 800~600 Ma, younger than typical ages of Grenvillian events, which may reflect younger inherited zircon cores or significant isotopic resetting. (3) The age of ~530 Ma of zircon rims is interpreted to represent the post-peak cooling stage of the Pan-African tectono-thermal event. [Significance] This study examined the PâT conditions and the zircon ages of the spinelâcordierite granulite in the Mirror Peninsula. In combination with previous results, the PâTât path constructed for the spinelâcordierite granulite provides new constraints on the evolution of the Prydz Bay belt during the Pan-African period
Oxygen-glucose deprivation induces ATP release via maxi-anion channels in astrocytes
ATP represents a major gliotransmitter that serves as a signaling molecule for the cross talk between glial and neuronal cells. ATP has been shown to be released by astrocytes in response to a number of stimuli under nonischemic conditions. In this study, using a luciferin-luciferase assay, we found that mouse astrocytes in primary culture also exhibit massive release of ATP in response to ischemic stress mimicked by oxygen-glucose deprivation (OGD). Using a biosensor technique, the local ATP concentration at the surface of single astrocytes was found to increase to around 4Â ÎŒM. The OGD-induced ATP release was inhibited by Gd3+ and arachidonic acid but not by blockers of volume-sensitive outwardly rectifying Clâ channels, cystic fibrosis transmembrane conductance regulator (CFTR), multidrug resistance-related protein (MRP), connexin or pannexin hemichannels, P2X7 receptors, and exocytotic vesicular transport. In cell-attached patches on single astrocytes, OGD caused activation of maxi-anion channels that were sensitive to Gd3+ and arachidonic acid. The channel was found to be permeable to ATP4â with a permeability ratio of PATP/PClâ=â0.11. Thus, it is concluded that ischemic stress induces ATP release from astrocytes and that the maxi-anion channel may serve as a major ATP-releasing pathway under ischemic conditions
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