1,794 research outputs found
Phosphorylated claspin interacts with a phosphate-binding site in the kinase domain of Chk1 during ATR-mediated activation
Claspin is essential for the ATR-dependent activation of Chk1 in Xenopus egg extracts containing incompletely replicated or UV-damaged DNA. The activated form of Claspin contains two repeated phosphopeptide motifs that mediate its binding to Chk1. We show that these phosphopeptide motifs bind to Chk1 by means of its N-terminal kinase domain. The binding site on Chk1 involves a positively charged cluster of amino acids that contains lysine 54, arginine 129, threonine 153, and arginine 162. Mutagenesis of these residues strongly compromises the ability of Chk1 to interact with Claspin. These amino acids lie within regions of Chk1 that are involved in various aspects of its catalytic function. The predicted position on Chk1 of the phosphate group from Claspin corresponds to the location of activation-loop phosphorylation in various kinases. In addition, we have obtained evidence that the C-terminal regulatory domain of Chk1, which does not form a stable complex with Claspin under our assay conditions, nonetheless has some role in Claspin-dependent activation. Overall, these results indicate that Claspin docks with a phosphate-binding site in the catalytic domain of Chk1 during activation by ATR. Phosphorylated Claspin may mimic an activating phosphorylation of Chk1 during this process
Iterative DNA Coding Scheme With GC Balance and Run-Length Constraints Using a Greedy Algorithm
In this paper, we propose a novel iterative encoding algorithm for DNA
storage to satisfy both the GC balance and run-length constraints using a
greedy algorithm. DNA strands with run-length more than three and the GC
balance ratio far from 50\% are known to be prone to errors. The proposed
encoding algorithm stores data at high information density with high
flexibility of run-length at most and GC balance between for
arbitrary and . More importantly, we propose a novel mapping method
to reduce the average bit error compared to the randomly generated mapping
method, using a greedy algorithm. The proposed algorithm is implemented through
iterative encoding, consisting of three main steps: randomization, M-ary
mapping, and verification. It has an information density of 1.8616 bits/nt in
the case of , which approaches the theoretical upper bound of 1.98
bits/nt, while satisfying two constraints. Also, the average bit error caused
by the one nt error is 2.3455 bits, which is reduced by , compared to
the randomized mapping.Comment: 19 page
Applications of pre-open sets
[EN] Using the concept of pre-open set, we introduce and study topological properties of pre-limit points, pre-derived sets, preinterior and pre-closure of a set, pre-interior points, pre-border, prefrontier and pre-exterior. The relations between pre-derived set (resp. pre-limit point, pre-interior (point), pre-border, pre-frontier, and preexterior) and α-derived set (resp. α-limit point, α-interior (point), α-border,
α-frontier, and α-exterior) are investigatedJun, YB.; Jeong, SW.; Lee, HJ.; Lee, JW. (2008). Applications of pre-open sets. Applied General Topology. 9(2):213-228. https://doi.org/10.4995/agt.2008.18022132289
On Recognizing Texts of Arbitrary Shapes with 2D Self-Attention
Scene text recognition (STR) is the task of recognizing character sequences
in natural scenes. While there have been great advances in STR methods, current
methods still fail to recognize texts in arbitrary shapes, such as heavily
curved or rotated texts, which are abundant in daily life (e.g. restaurant
signs, product labels, company logos, etc). This paper introduces a novel
architecture to recognizing texts of arbitrary shapes, named Self-Attention
Text Recognition Network (SATRN), which is inspired by the Transformer. SATRN
utilizes the self-attention mechanism to describe two-dimensional (2D) spatial
dependencies of characters in a scene text image. Exploiting the full-graph
propagation of self-attention, SATRN can recognize texts with arbitrary
arrangements and large inter-character spacing. As a result, SATRN outperforms
existing STR models by a large margin of 5.7 pp on average in "irregular text"
benchmarks. We provide empirical analyses that illustrate the inner mechanisms
and the extent to which the model is applicable (e.g. rotated and multi-line
text). We will open-source the code
Antidiabetic Activities of Abutilon indicum (L.) Sweet Are Mediated by Enhancement of Adipocyte Differentiation and Activation of the GLUT1 Promoter
Abutilon indicum (L.) Sweet is an Asian phytomedicine traditionally used to treat several disorders, including diabetes mellitus. However, molecular mechanisms supporting the antidiabetic effect of A. indicum L. remain unknown. The aim of this study was to evaluate whether extract of A. indicum L. improves insulin sensitivity. First, we observed the antidiabetic activity of aqueous extract of the entire plant (leaves, twigs and roots) of A. indicum L. on postprandial plasma glucose in diabetic rats. The subsequent experiments revealed that butanol fractions of the extract bind to PPARγ and activate 3T3-L1 differentiation. To measure glucose uptake enhanced by insulin-like activity, we used rat diaphragm incubated with various concentrations of the crude extract and found that the extract enhances glucose consumption in the incubated solution. Our data also indicate that the crude extract and the fractions (water and butanol) did not affect the activity of kinases involved in Akt and GSK-3β pathways; however, the reporter assay showed that the crude extract could activate glucose transporter 1 (GLUT1) promoter activity. These results suggest that the extract from A. indicum L. may be beneficial for reducing insulin resistance through its potency in regulating adipocyte differentiation through PPARγ agonist activity, and increasing glucose utilization via GLUT1
The Connection between Star-Forming Galaxies, AGN Host Galaxies and Early-Type Galaxies in the SDSS
We present a study of the connection between star-forming galaxies, AGN host
galaxies, and normal early-type galaxies in the Sloan Digital Sky Survey
(SDSS). Using the SDSS DR5 and DR4plus data, we select our early-type galaxy
sample in the color versus color-gradient space, and we classify the spectral
types of the selected early-type galaxies into normal, star-forming, Seyfert,
and LINER classes, using several spectral line flux ratios. We investigate the
slope in the fundamental space for each class of early-type galaxies and find
that there are obvious differences in the slopes of the fundamental planes
(FPs) among the different classes of early-type galaxies, in the sense that the
slopes for Seyferts and star-forming galaxies are flatter than those for normal
galaxies and LINERs. This may be the first identification of the systematic
variation of the FP slope among the subclasses of early-type galaxies. The
difference in the FP slope might be caused by the difference in the degree of
nonhomology among different classes or by the difference of gas contents in
their merging progenitors. One possible scenario is that the AGN host galaxies
and star-forming galaxies are formed by gas-rich merging and that they may
evolve into normal early-type galaxies after finishing their star formation or
AGN activities.Comment: 5 pages with emulateapj, 2 figures, accepted for publication in the
Astrophysical Journal Letter
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