780 research outputs found
Correlation Analysis for Protein Evolutionary Family Based on Amino Acid Position Mutations and Application in PDZ Domain
BACKGROUND: It has been widely recognized that the mutations at specific directions are caused by the functional constraints in protein family and the directional mutations at certain positions control the evolutionary direction of the protein family. The mutations at different positions, even distantly separated, are mutually coupled and form an evolutionary network. Finding the controlling mutative positions and the mutative network among residues are firstly important for protein rational design and enzyme engineering. METHODOLOGY: A computational approach, namely amino acid position conservation-mutation correlation analysis (CMCA), is developed to predict mutually mutative positions and find the evolutionary network in protein family. The amino acid position mutative function, which is the foundational equation of CMCA measuring the mutation of a residue at a position, is derived from the MSA (multiple structure alignment) database of protein evolutionary family. Then the position conservation correlation matrix and position mutation correlation matrix is constructed from the amino acid position mutative equation. Unlike traditional SCA (statistical coupling analysis) approach, which is based on the statistical analysis of position conservations, the CMCA focuses on the correlation analysis of position mutations. CONCLUSIONS: As an example the CMCA approach is used to study the PDZ domain of protein family, and the results well illustrate the distantly allosteric mechanism in PDZ protein family, and find the functional mutative network among residues. We expect that the CMCA approach may find applications in protein engineering study, and suggest new strategy to improve bioactivities and physicochemical properties of enzymes
Graph Mining for Cybersecurity: A Survey
The explosive growth of cyber attacks nowadays, such as malware, spam, and
intrusions, caused severe consequences on society. Securing cyberspace has
become an utmost concern for organizations and governments. Traditional Machine
Learning (ML) based methods are extensively used in detecting cyber threats,
but they hardly model the correlations between real-world cyber entities. In
recent years, with the proliferation of graph mining techniques, many
researchers investigated these techniques for capturing correlations between
cyber entities and achieving high performance. It is imperative to summarize
existing graph-based cybersecurity solutions to provide a guide for future
studies. Therefore, as a key contribution of this paper, we provide a
comprehensive review of graph mining for cybersecurity, including an overview
of cybersecurity tasks, the typical graph mining techniques, and the general
process of applying them to cybersecurity, as well as various solutions for
different cybersecurity tasks. For each task, we probe into relevant methods
and highlight the graph types, graph approaches, and task levels in their
modeling. Furthermore, we collect open datasets and toolkits for graph-based
cybersecurity. Finally, we outlook the potential directions of this field for
future research
AIMS: All-Inclusive Multi-Level Segmentation
Despite the progress of image segmentation for accurate visual entity
segmentation, completing the diverse requirements of image editing applications
for different-level region-of-interest selections remains unsolved. In this
paper, we propose a new task, All-Inclusive Multi-Level Segmentation (AIMS),
which segments visual regions into three levels: part, entity, and relation
(two entities with some semantic relationships). We also build a unified AIMS
model through multi-dataset multi-task training to address the two major
challenges of annotation inconsistency and task correlation. Specifically, we
propose task complementarity, association, and prompt mask encoder for
three-level predictions. Extensive experiments demonstrate the effectiveness
and generalization capacity of our method compared to other state-of-the-art
methods on a single dataset or the concurrent work on segmenting anything. We
will make our code and training model publicly available.Comment: Technical Repor
Performance studies of a SiPM-readout system with a pico-second timing chip
A pico-second timing (PIST) front-end electronic chip has been developed
using CMOS technology for future electron-positron collider
experiments (namely Higgs factories). Extensive tests have been performed to
evaluate the timing performance of a dedicated SiPM-readout system equipped
with a PIST chip. The results show that the system timing resolution can
achieve for SiPM signals at the minimum-ionizing particles
(MIP) level () and better than for signals
larger than , while the PIST intrinsic timing resolution is
. The PIST dynamic range has been further extended
using the time-over-threshold (ToT) technique, which can cover the SiPM
response spanning from to
Analysis of the expression pattern of the BCL11B gene and its relatives in patients with T-cell acute lymphoblastic leukemia
<p>Abstract</p> <p>Background</p> <p>In a human T-cell acute lymphoblastic leukemia (T-ALL) cell line (Molt-4), siRNA-mediated suppression of <it>BCL11B </it>expression was shown to inhibit proliferation and induce apoptosis, functions which may be related to genes involved in apoptosis (such as <it>TNFSF10 </it>and <it>BCL2L1</it>) and TGF-Ξ² pathways (such as <it>SPP1</it>and <it>CREBBP</it>).</p> <p>Methods</p> <p>The expression levels of the above mentioned genes and their correlation with the <it>BCL11B </it>gene were analyzed in patients with T-ALL using the TaqMan and SYBR Green I real-time polymerase chain reaction technique.</p> <p>Results</p> <p>Expression levels of <it>BCL11B, BCL2L1</it>, and <it>CREBBP </it>mRNA in T-ALL patients were significantly higher than those from healthy controls (<it>P <</it>0.05). In T-ALL patients, the <it>BCL11B </it>expression level was negatively correlated with the <it>BCL2L1 </it>expression level (<it>r</it><sub>s </sub>= -0.700; <it>P </it><it><</it>0.05), and positively correlated with the <it>SPP1 </it>expression level (<it>r</it><sub>s </sub>= 0.683; <it>P </it><it><</it>0.05). In healthy controls, the <it>BCL11B </it>expression level did not correlate with the <it>TNFSF10</it>, <it>BCL2L1</it>, <it>SPP1</it>, or <it>CREBBP </it>expression levels.</p> <p>Conclusions</p> <p>Over-expression of <it>BCL11B </it>might play a role in anti-apoptosis in T-ALL cells through up-regulation of its downstream genes <it>BCL2L1 </it>and <it>CREBBP</it>.</p
A hybrid column generation algorithm based on metaheuristic optimization
The exact solution and heuristic solution have their own strengths and weaknesses on solving the Vehicle Routing Problems with Time Windows (VRPTW). This paper proposes a hybrid Column Generation Algorithm with Metaheuristic Optimization (CGAMO) to overcome their weaknesses. Firstly, a Modified Labelling Algorithm (MLA) in the sub-problem of path searching is analysed. And a search strategy in CGAMO based on the demand of sub-problem is proposed to improve the searching efficiency. While putting the paths found in the sub-problem into the main problems of CGAMO, the iterations may fall into endless loops. To avoid this problem and keep the main problems in a reasonable size, two conditions on saving the old paths in the main problem are used. These conditions enlarge the number of constraints considered in the iterations to strengthen the limits of dual variables. Through analysing the sub-problem, we can find many useless paths that have no effect on the objective function. Secondly, in order to reduce the number of useless paths and improve the efficiency, this paper proposes a heuristic optimization strategy of CGAMO for dual variables. It is supposed to accelerate the solving speed from the view of on the dual problem. Finally, extensive experiments show that CGAMO achieves a better performance than other state-of-the-art methods on solving VRPTW. The comparative experiments also present the parameters sensitivity analysis, including the different effects of MLA in the different path selection strategies, the characteristics and the applicable scopes of the two pathkeeping conditions in the main problem.
First published online:Β 25 Oct 201
Evaluation of Uterosacral Ligament Involvement in Deep Endometriosis by Transvaginal Ultrasonography
This study was designed to conclude the ultrasonic characteristics of uterosacral ligament (USL) lesions involved by endometriosis and evaluated the value of transvaginal sonography (TVS) in diagnosing USL involvement in deep infiltrating endometriosis (DIE). A total of one hundred and eighteen patients with DIE were included in the study and underwent surgery. All these patients were evaluated by transvaginal ultrasound examination by one trained examiner. The gold standard for diagnosis was surgery and histopathology. 85 patients with USL endometriosis were confirmed by surgical pathology. 84 patients were diagnosed USL endometriosis by TVS and 81 of which were confirmed by the gold standard. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of TVS for diagnosing USL endometriosis were 95.3, 90.9, 96.4, 88.2, and 94.1%, respectively. According to the ultrasound characteristics of USL endometriosis, we summarized four types: Type I. thickened and stiff lesions, Type II. local nodules, Type III. irregular striped lesions, and Type IV. mixed lesions. The conclusion of the study was that TVS was a convenient, accurate and first-line diagnostic technique for USL endometriosis and the USL lesions could be summarized into four types according to the ultrasound morphological changes
Atomic-scale observation of localized phonons at FeSe/SrTiO3 interface
In single unit-cell FeSe grown on SrTiO3, the superconductivity transition
temperature features a significant enhancement. Local phonon modes at the
interface associated with electron-phonon coupling may play an important role
in the interface-induced enhancement. However, such phonon modes have eluded
direct experimental observations. Indeed, the complicated atomic structure of
the interface brings challenges to obtain the accurate structure-phonon
relation knowledge from either experiment or theory, thus hindering our
understanding of the enhancement mechanism. Here, we achieve direct
characterizations of atomic structure and phonon modes at the FeSe/SrTiO3
interface with atomically resolved imaging and electron energy loss
spectroscopy in a scanning transmission electron microscope. We find several
phonon modes highly localized (~1.3 nm) at the unique double layer Ti-O
termination at the interface, one of which (~ 83 meV) engages in strong
interactions with the electrons in FeSe based on ab initio calculations. The
electron-phonon coupling strength for such a localized interface phonon with
short-range interactions is comparable to that of Fuchs-Kliewer (FK) phonon
mode with long-rang interactions. Thus, our atomic-scale study provides new
insights into understanding the origin of superconductivity enhancement at the
FeSe/SrTiO3 interface
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