1,431 research outputs found
A Nuclear Protease Required for Flowering-Time Regulation in Arabidopsis Reduces the Abundance of SMALL UBIQUITIN-RELATED MODIFIER Conjugates
Negative ion Time Projection Chamber operation with SF at nearly atmospheric pressure
We present measurements of drift velocities and mobilities of some innovative
negative ion gas mixtures at nearly atmospheric pressure based on SF as
electronegative capture agent and of pure SF at various pressures,
performed with the NITEC detector. NITEC is a Time Projection Chamber with 5 cm
drift distance readout by a GEMPix, a triple thin GEMs coupled to a
Quad-Timepix chip, directly sensitive to the deposited charge on each of the 55
55 m pixel. Our results contribute to expanding the knowledge
on the innovative use of SF as negative ion gas and extend to triple thin
GEMs the possibility of negative ion operation for the first time. Above all,
our findings show the feasibility of negative ion operation with
He:CF:SF at 610 Torr, opening extremely interesting possibility for
next generation directional Dark Matter detectors at 1 bar
MicroRNA Signature in Human Normal and Tumoral Neural Stem Cells
MicroRNAs, also called miRNAs or simply miR‐, represent a unique class of non‐coding
RNAs that have gained exponential interest during recent years because of their determinant
involvement in regulating the expression of several genes. Despite the increasing number of
mature miRNAs recognized in the human species, only a limited proportion is engaged in the
ontogeny of the central nervous system (CNS). miRNAs also play a pivotal role during the
transition of normal neural stem cells (NSCs) into tumor‐forming NSCs. More specifically,
extensive studies have identified some shared miRNAs between NSCs and neural cancer stem cells
(CSCs), namely miR‐7, ‐124, ‐125, ‐181 and miR‐9, ‐10, ‐130. In the context of NSCs, miRNAs are
intercalated from embryonic stages throughout the differentiation pathway in order to achieve
mature neuronal lineages. Within CSCs, under a different cellular context, miRNAs perform tumor
suppressive or oncogenic functions that govern the homeostasis of brain tumors. This review will
draw attention to the most characterizing studies dealing with miRNAs engaged in neurogenesis
and in the tumoral neural stem cell context, offering the reader insight into the power of next
generation miRNA‐targeted therapies against brain malignancies
Coalescence instability in chromospheric partially ionized plasmas
This is the author accepted manuscript. The final version is available from AIP Publishing via the DOI in this recordData availability:
The data that support the findings of this study are available from the corresponding author upon reasonable request.
The (PIP) code is available at the following url: https://github.com/AstroSnow/PIPFast magnetic reconnection plays a fundamental role in driving explosive dynamics and heating in the solar chromosphere. The reconnection time scale of traditional models is shortened at the onset of the coalescence instability, which
forms a turbulent reconnecting current sheet through plasmoid interaction. In this work we aim to investigate the role of
partial ionisation on the development of fast reconnection through the study of the coalescence instability of plasmoids.
Unlike the processes occurring in fully ionised coronal plasmas, relatively little is known about how fast reconnection develops in partially ionised plasmas of the chromosphere. We present 2.5D numerical simulations of coalescing
plasmoids in a single fluid magnetohydrodynamic (MHD) model, and a two-fluid model of a partially ionised plasma
(PIP). We find that in the PIP model, which has the same total density as the MHD model but an initial plasma density
two orders of magnitude smaller, plasmoid coalescence is faster than the MHD case, following the faster thinning of
the current sheet and secondary plasmoid dynamics. Secondary plasmoids form in the PIP model where the effective
Lundquist number S = 7.8·103
, but are absent from the MHD case where S = 9.7·103
: these are responsible for a more
violent reconnection. Secondary plasmoids also form in linearly stable conditions as a consequence of the non-linear
dynamics of the neutrals in the inflow. In the light of these results we can affirm that two-fluid effects play a major role
on the processes occurring in the solar chromosphere.Science and Technology Facilities Council (STFC
Experimental results of crystal-assisted slow extraction at the SPS
The possibility of extracting highly energetic particles from the Super
Proton Synchrotron (SPS) by means of silicon bent crystals has been explored
since the 1990's. The channelling effect of a bent crystal can be used to
strongly deflect primary protons and eject them from the synchrotron. Many
studies and experiments have been carried out to investigate crystal
channelling effects. The extraction of 120 and 270 GeV proton beams has already
been demonstrated in the SPS with dedicated experiments located in the ring.
Presently in the SPS, the UA9 experiment is performing studies to evaluate the
possibility to use bent silicon crystals to steer particle beams in high energy
accelerators. Recent studies on the feasibility of extraction from the SPS have
been made using the UA9 infrastructure with a longer-term view of using
crystals to help mitigate slow extraction induced activation of the SPS. In
this paper, the possibility to eject particles into the extraction channel in
LSS2 using the bent crystals already installed in the SPS is presented. Details
of the concept, simulations and measurements carried out with beam are
presented, before the outlook for the future is discussed.Comment: 4 pages, 7 figures, submitted to to International Particle
Accelerator Conference (IPAC) 2017 in Copenhagen, Denmar
A triple GEM gamma camera for medical application
Abstract A Gamma Camera for medical applications 10 × 10 cm 2 has been built using a triple GEM chamber prototype. The photon converters placed in front of the three GEM foils, has been realized with different technologies. The chamber, High Voltage supplied with a new active divider made in Frascati, is readout through 64 pads, 1 mm 2 wide, organized in a row of 8 cm long, with LHCb ASDQ chip. This Gamma Camera can be used both for X-ray movie and PET-SPECT imaging; this chamber prototype is placed in a scanner system, creating images of 8 × 8 cm 2 . Several measurements have been performed using phantom and radioactive sources of Tc 99 m ( 140 keV ) and Na 22 ( 511 keV ) . Results on spatial resolution and image reconstruction are presented
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