University of Electronic Science and Technology of China

About: University of Electronic Science and Technology of China is a education organization based out in Chengdu, China. It is known for research contribution in the topics: Computer science & Antenna (radio). The organization has 50594 authors who have published 58502 publications receiving 711188 citations. The organization is also known as: UESTC.

Increasing frequencies of site-specific mutagenesis and gene targeting in Arabidopsis by manipulating DNA repair pathways

Abstract: Customizable, sequence-specific nucleases make it possible to precisely modify the genomes of many higher organisms, including diverse plant species (Voytas 2013). There are three primary types of sequence-specific nucleases, namely, zinc finger nucleases (ZFNs) (Kim et al. 1996; Carroll 2011), TAL effector nucleases (TALENs) (Christian et al. 2010; Bogdanove and Voytas 2011), and meganucleases (Smith et al. 2006; Paques and Duchateau 2007). All three nuclease types introduce targeted DNA double-strand breaks (DSBs), which activate the cell's DNA repair pathways, principally nonhomologous end-joining (NHEJ) and homologous recombination (HR) (Kanaar et al. 1998; Puchta 2005; Hartlerode and Scully 2009). NHEJ predominates in nonreplicating cells and repair is often imprecise, such that mutations are introduced at the cut site. HR, which enables gene replacement or gene targeting (GT), predominates in replicating cells. Because genome modifications made with customizable nucleases rely on DSB repair, it should be possible to manipulate DNA repair pathways to influence the type and frequency of targeted modifications attained. For example, promoting NHEJ should enhance nuclease-mediated site-specific mutagenesis; however, there are no reports of this approach being successful in plants. Strategies to enhance HR have been reported in a few plant studies; for example, high-frequency HR was obtained by overexpressing the yeast RAD54 gene (Shaked et al. 2005). Enhanced HR was also attained in Arabidopsis by knocking out RAD50 (Gherbi et al. 2001) or CAF1(Endo et al. 2006) or by overexpressing SMC6B (also known as MIM) (Hanin et al. 2000). Almost all of these studies used a GUS transgene reporter that measures intrachromosomal, single-strand annealing (SSA) and/or synthesis-dependent strand annealing (SDSA) in which sister chromatids or homologous chromosomes are used as repair templates (Orel et al. 2003; Puchta 2005). For GT, exogenous donors or chromosomally integrated, nonallelic donors are usually used. The repair mechanisms used in GT, therefore, could be quite different, and it remains to be determined whether previously demonstrated manipulations of DNA repair pathways will apply to GT of endogenous genes. One of the few attempts to influence GT in plants involved overexpression of the bacterial RecA protein, which enhanced the fidelity of DSB-induced GT in tobacco but not the overall GT frequency (Reiss et al. 2000). In this study, we tested the consequence of manipulating key regulators of NHEJ and HR on targeted mutagenesis or GT mediated by sequence-specific nucleases. In classic NHEJ (C-NHEJ), KU70 dimerizes with KU80 to form KU protein complexes, which directly bind to DSBs to initiate repair (Pastwa and Blasiak 2003). In HR, SMC6 acts when sister chromatids are used as repair templates in both human (De Piccoli et al. 2006; Potts et al. 2006) and Arabidopsis cells (Watanabe et al. 2009). SMC6 dimerizes with SMC5 to form SMC6/5 complexes that initiate repair of DSBs using sister chromatids as templates (Potts 2009). The upstream positions of KU70 and SMC6 in the NHEJ or HR pathways, respectively, made them good candidates as regulators of DNA repair pathway choice. We also chose LIG4, because it carries out a well-known and conserved function downstream from KU (Pastwa and Blasiak 2003). A ZFN that targets the endogenous Arabidopsis ADH1 gene was used to create DSBs (Zhang et al. 2010), and NHEJ mutagenesis and GT were measured in whole seedlings and rosette leaf protoplasts in each of the three DNA repair mutant backgrounds. Our results clearly demonstrate that manipulating these key DNA repair genes in Arabidopsis can influence the efficiencies and outcomes of targeted mutagenesis and GT.

A comparative study of different references for EEG spectral mapping: the issue of the neutral reference and the use of the infinity reference.

Abstract: Based on EEG data recorded from 11 subjects with eyes open and the left mastoid (M) reference, three data sets were generated by re-referencing to the conventional linked mastoids (L), average (A) and the new 'infinity' (I) reference provided by the reference electrode standardization technique (REST, Yao 2001 Physiol. Meas. 22 693–711). The EEG power in the alpha frequency band with the four different references was calculated and compared with respect to the total energy and spatial amplitude weight centre (AWC) coordinates, to compare the effects of different references on power mapping in the frequency domain. Compared with the I reference, the AWCs of the EEG with the M reference show significant shifts to the right, frontal and superficial positions, the L reference significant shifts to frontal and superficial positions, and the A reference shifts the AWC significantly to a deeper position. Furthermore, the power maps of the M and L references have larger total power than the I reference, while that of the A reference has the smallest total power. These results confirm that different choices of reference electrodes result in systematic changes in the distribution of EEG frequency power, and in order to reduce the effect of such systematic shifts on the explanation of EEG mappings, a common reference is necessary for EEG research. We recommend the I reference for objective use in cross-laboratory studies and clinical practices, as it is far from all the other electrodes and can act as a neutral reference.

Scene Text Detection with Supervised Pyramid Context Network

Abstract: Scene text detection methods based on deep learning have achieved remarkable results over the past years. However, due to the high diversity and complexity of natural scenes, previous state-of-the-art text detection methods may still produce a considerable amount of false positives, when applied to images captured in real-world environments. To tackle this issue, mainly inspired by Mask R-CNN, we propose in this paper an effective model for scene text detection, which is based on Feature Pyramid Network (FPN) and instance segmentation. We propose a supervised pyramid context network (SPCNET) to precisely locate text regions while suppressing false positives.Benefited from the guidance of semantic information and sharing FPN, SPCNET obtains significantly enhanced performance while introducing marginal extra computation. Experiments on standard datasets demonstrate that our SPCNET clearly outperforms start-of-the-art methods. Specifically, it achieves an F-measure of 92.1% on ICDAR2013, 87.2% on ICDAR2015, 74.1% on ICDAR2017 MLT and 82.9% on