185 research outputs found
Adipose-derived mesenchymal stem cells attenuate ischemic brain injuries in rats by modulating miR-21-3p/MAT2B signaling transduction
Aim To explore the mechanism underlying the protective
effect of adipose-derived mesenchymal stem cells (ADMSCs)
against ischemic stroke by focusing on miR-21-3p/
MAT2B axis.
Methods Ischemic brain injury was induced in 126 rats
by middle cerebral artery occlusion (MCAO). The effect of
ADMSC administration on blood-brain barrier (BBB) condition,
apoptosis, inflammation, and the activity of miR-21-
3p/MAT2B axis was assessed. The role of miR-21-3p inhibition
in the function of ADMSCs was further validated in in
vitro neural cells.
Results ADMSCs administration improved BBB condition,
inhibited apoptosis, and suppressed inflammation. It also
reduced the abnormally high level of miR-21-3p in MCAO
rats. Dual luciferase assays showed that miR-21-3p directly
inhibited the MAT2B expression in neural cells, and miR-21
-3p inhibition by inhibitor or ADMSC-derived exosomes in
neurons attenuated hypoxia/reoxygenation-induced impairments
similarly to that of ADMSCs in vivo.
Conclusion This study confirmed the protective effect
of ADMSCs against ischemic brain injury exerted by suppressing
miR-21-3p level and up-regulating MAT2B level
H2RBox-v2: Boosting HBox-supervised Oriented Object Detection via Symmetric Learning
With the increasing demand for oriented object detection e.g. in autonomous
driving and remote sensing, the oriented annotation has become a
labor-intensive work. To make full use of existing horizontally annotated
datasets and reduce the annotation cost, a weakly-supervised detector H2RBox
for learning the rotated box (RBox) from the horizontal box (HBox) has been
proposed and received great attention. This paper presents a new version,
H2RBox-v2, to further bridge the gap between HBox-supervised and
RBox-supervised oriented object detection. While exploiting axisymmetry via
flipping and rotating consistencies is available through our theoretical
analysis, H2RBox-v2, using a weakly-supervised branch similar to H2RBox, is
embedded with a novel self-supervised branch that learns orientations from the
symmetry inherent in the image of objects. Complemented by modules to cope with
peripheral issues, e.g. angular periodicity, a stable and effective solution is
achieved. To our knowledge, H2RBox-v2 is the first symmetry-supervised paradigm
for oriented object detection. Compared to H2RBox, our method is less
susceptible to low annotation quality and insufficient training data, which in
such cases is expected to give a competitive performance much closer to
fully-supervised oriented object detectors. Specifically, the performance
comparison between H2RBox-v2 and Rotated FCOS on DOTA-v1.0/1.5/2.0 is
72.31%/64.76%/50.33% vs. 72.44%/64.53%/51.77%, 89.66% vs. 88.99% on HRSC, and
42.27% vs. 41.25% on FAIR1M.Comment: 13 pages, 4 figures, 7 tables, the source code is available at
https://github.com/open-mmlab/mmrotat
Effect of Nanoparticle Surface Modification and Filling Concentration on Space Charge Characteristics in TiO 2
This paper focuses on the space charge characteristics in TiO2/cross-linked polyethylene (XLPE) nanocomposites; the unmodified and modified by dimethyloctylsilane (MDOS) TiO2 nanoparticles were added to XLPE matrix with different mass concentrations (1 wt%, 3 wt%, and 5 wt%). The scanning electron microscope (SEM) showed that the MDOS coupling agent could improve the compatibility between TiO2 nanoparticles and XLPE matrix to some extent and reduce the agglomeration of TiO2 nanoparticles compared with unmodified TiO2 nanoparticles; the volume resistivity testing indicated that the volume resistivity of TiO2/XLPE nanocomposites was higher than Pure-XLPE and increased with the increase of filling concentrations. According to the pulsed electroacoustic (PEA) measurements, it was concluded that the space charge accumulation was suppressed by filling TiO2 nanoparticles and the distribution of electric field in samples was improved greatly. In addition, it was found that the injection of homocharge was more obvious in MDOS-TiO2/XLPE than that in UN-TiO2/XLPE and the homocharge injection decreased with the increase of filling concentration
Increasing Cytosine Base Editing Scope and Efficiency With Engineered Cas9-PmCDA1 Fusions and the Modified sgRNA in Rice
Base editors that do not require double-stranded DNA cleavage or homology-directed repair enable higher efficiency and cleaner substitution of targeted single nucleotides in genomic DNA than conventional approaches. However, their broad applications are limited within the editing window of several base pairs from the canonical NGG protospacer adjacent motif (PAM) sequence. In this study, we fused the D10A nickase of several Streptococcus pyogenes Cas9 (SpCas9) variants with Petromyzon marinus cytidine deaminase 1 (PmCDA1) and uracil DNA glycosylase inhibitor (UGI) and developed two new effective PmCDA1-based cytosine base editors (pBEs), SpCas9 nickase (SpCas9n)-pBE and VQR nickase (VQRn)-pBE, which expanded the scope of genome targeting for cytosine-to-thymine (C-to-T) substitutions in rice. Four of six and 12 of 18 target sites selected randomly in SpCas9n-pBE and VQRn-pBE, respectively were base edited with frequencies of 4–90% in T0 plants. The effective deaminase window typically spanned positions 1–7 within the protospacer and the single target C showed the maximum C-to-T frequency at or near position 3, counting the end distal to PAM as position 1. In addition, the modified single guide RNA (sgRNA) improved the base editing efficiencies of VQRn-pBE with 1.3- to 7.6-fold increases compared with the native sgRNA, and targets that could not be mutated using the native sgRNA were edited successfully using the modified sgRNA. These newly developed base editors can be used to realize C-to-T substitutions and may become powerful tools for both basic scientific research and crop breeding in rice
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
Nanoscale Characterization of Electrolyte Diffusion, Interface Morphology Disruption and Surface Dynamics of Polymer Melt Films Adsorbed on Graphene
- …