10 research outputs found
A Relay System for Semantic Image Transmission based on Shared Feature Extraction and Hyperprior Entropy Compression
Nowadays, the need for high-quality image reconstruction and restoration is
more and more urgent. However, most image transmission systems may suffer from
image quality degradation or transmission interruption in the face of
interference such as channel noise and link fading. To solve this problem, a
relay communication network for semantic image transmission based on shared
feature extraction and hyperprior entropy compression (HEC) is proposed, where
the shared feature extraction technology based on Pearson correlation is
proposed to eliminate partial shared feature of extracted semantic latent
feature. In addition, the HEC technology is used to resist the effect of
channel noise and link fading and carried out respectively at the source node
and the relay node. Experimental results demonstrate that compared with other
recent research methods, the proposed system has lower transmission overhead
and higher semantic image transmission performance. Particularly, under the
same conditions, the multi-scale structural similarity (MS-SSIM) of this system
is superior to the comparison method by approximately 0.2
Non-Orthogonal Multiple Access Enhanced Multi-User Semantic Communication
Semantic communication serves as a novel paradigm and attracts the broad
interest of researchers. One critical aspect of it is the multi-user semantic
communication theory, which can further promote its application to the
practical network environment. While most existing works focused on the design
of end-to-end single-user semantic transmission, a novel non-orthogonal
multiple access (NOMA)-based multi-user semantic communication system named
NOMASC is proposed in this paper. The proposed system can support semantic
tranmission of multiple users with diverse modalities of source information. To
avoid high demand for hardware, an asymmetric quantizer is employed at the end
of the semantic encoder for discretizing the continuous full-resolution
semantic feature. In addition, a neural network model is proposed for mapping
the discrete feature into self-learned symbols and accomplishing intelligent
multi-user detection (MUD) at the receiver. Simulation results demonstrate that
the proposed system holds good performance in non-orthogonal transmission of
multiple user signals and outperforms the other methods, especially at
low-to-medium SNRs. Moreover, it has high robustness under various simulation
settings and mismatched test scenarios.Comment: accepted by IEEE Transactions on Cognitive Communications and
Networkin
Evolutionary Analysis of Structural Protein Gene VP1 of Foot-and-Mouth Disease Virus Serotype Asia 1
Foot-and-mouth disease virus (FMDV) serotype Asia 1 was mostly endemic in Asia and then was responsible for economically important viral disease of cloven-hoofed animals, but the study on its selection and evolutionary process is comparatively rare. In this study, we characterized 377 isolates from Asia collected up until 2012, including four vaccine strains. Maximum likelihood analysis suggested that the strains circulating in Asia were classified into 8 different groups (groups I–VIII) or were unclassified (viruses collected before 2000). On the basis of divergence time analyses, we infer that the TMRCA of Asia 1 virus existed approximately 86.29 years ago. The result suggested that the virus had a high mutation rate (5.745 × 10−3 substitutions/site/year) in comparison to the other serotypes of FMDV VP1 gene. Furthermore, the structural protein VP1 was under lower selection pressure and the positive selection occurred at many sites, and four codons (positions 141, 146, 151, and 169) were located in known critical antigenic residues. The remaining sites were not located in known functional regions and were moderately conserved, and the reason for supporting all sites under positive selection remains to be elucidated because the power of these analyses was largely unknown
Analysis of synonymous codon usage in Hepatitis A virus
<p>Abstract</p> <p>Background</p> <p>Hepatitis A virus is the causative agent of type A viral hepatitis, which causes occasional acute hepatitis. Nevertheless, little information about synonymous codon usage pattern of HAV genome in the process of its evolution is available. In this study, the key genetic determinants of codon usage in HAV were examined.</p> <p>Results</p> <p>The overall extent of codon usage bias in HAV is high in <it>Picornaviridae</it>. And the patterns of synonymous codon usage are quite different in HAV genomes from different location. The base composition is closely correlated with codon usage bias. Furthermore, the most important determinant that results in such a high codon bias in HAV is mutation pressure rather than natural selection.</p> <p>Conclusions</p> <p>HAV presents a higher codon usage bias than other members of <it>Picornaviridae</it>. Compositional constraint is a significant element that influences the variation of synonymous codon usage in HAV genome. Besides, mutation pressure is supposed to be the major factor shaping the hyperendemic codon usage pattern of HAV.</p
Transcript Profiling Identifies Early Response Genes against FMDV Infection in PK-15 Cells
Foot-and-mouth disease (FMD) is a highly contagious disease that results in enormous economic loses worldwide. Although the protection provided by vaccination is limited during early infection, it is recognized as the best method to prevent FMD outbreaks. Furthermore, the mechanism of host early responses against foot-and-mouth disease virus (FMDV) infection remains unclear. In our study, a pig kidney cell line (PK-15) was used as a cell model to reveal the mechanism of early pig responses to FMDV infection. Four non-treated control and four FMDV-treated PK-15 cells were sequenced with RNA-seq technology, and the differentially expressed genes (DEGs) were analyzed. The results showed that 1212 DEGs were in the FMDV-infected PK-15 cells, including 914 up-regulated and 298 down-regulated genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were significantly enriched in the tumor necrosis factor (TNF), cytokine-cytokine receptor interaction, NOD-like receptor, toll-like receptor, NF-κB, and the chemokine signaling pathways. To verify the results of the DEGs, 30 immune-related DEGs (19 up-regulated and 11 down-regulated) were selected for Quantitative Reverse Transcriptase polymerase chain reaction (RT-qPCR) verification. The results showed that RT-qPCR-measured genes exhibited a similar pattern as the RNA-seq analyses. Based on bioinformatics analysis, during FMDV early infection, we found that a series of cytokines, such as interleukins (IL6), chemokines (CXCL2, CCL20 and CCL4), and transcription factors (ZFP36, FOS, NFKBIA, ZBTB3, ZNF503, ZNF283, dymeclin (DYM), and orthodenticle homeobox 1 (OTX1)) were involved in the battle between FMDV and the host. Combined with their features and functions, we propose inflammation as the main early mechanism by which the host responds to FMDV infection. These data provide an additional panel of candidate genes for deciphering the mechanisms of a host’s early response against FMDV infection
Triple-Emitting Dumbbell Fluorescent Nanoprobe for Multicolor Detection and Imaging Applications
The
combination of different fluorescent species into one nanostructure
to develop fluorescent nanoparticles with multiple emission signatures
by a single wavelength excitation has become a very popular research
area in the field of multiplex bioanalysis, diagnostics, and multicolor
imaging. However, these novel hybrids must be elaborately designed
to ensure that the unique properties of each component are conveyed,
i.e., fluorescent species and nanoparticles, and are maximized without
serious interactions with each other. Herein, a first triple-fluorescence
dumbbell nanoprobe with large Stokes shift based on incorporating
fluorescein isothiocyanate (FITC) and lanthanide complexes onto Au–Fe<sub>3</sub>O<sub>4</sub> NPs was synthesized. This hybrid displays well-resolved
triple fluorescence emission, with FITC at 515 nm, TbÂ(III) complex
at 545 nm, and EuÂ(III) complex at 616 nm under a single-excitation
wavelength and is used for highly selective and sensitive colorimetric
detection of Cu<sup>2+</sup> with a detection limit of 30 nM. Under
different Cu<sup>2+</sup> concentrations, this hybrid exhibited distinguishable
multiple colors under UV light, and the color could change in the
presence of different concentrations of Cu<sup>2+</sup>. This sensor
for ratio/multianalyte microscopic imaging of Cu<sup>2+</sup> in HeLa
cells and BHK cells was also demonstrated. Target molecules, such
as folic acid, can be covalently attached to the fluorescent nanoparticle
surface to serve as an effective probe for simultaneous multicolor
imaging folate receptor-overexpressing HeLa cell lines in vitro
Basal Level p53 Suppresses Antiviral Immunity Against Foot-And-Mouth Disease Virus
Tumor suppressor protein p53 (p53) is a master transcription factor that plays key roles in cell cycle arrest, apoptosis, senescence, and metabolism, as well as regulation of innate immunity during virus infection. In order to facilitate their replication and spreading, viruses have evolved to manipulate p53 function through different strategies, with some requiring active p53 while others demand reduction/inhibition of p53 activity. However, there are no clear-cut reports about the roles of p53 during the infection of foot-and-mouth disease virus (FMDV), the causative agent of a highly contagious foot-and-mouth disease (FMD) of cloven-hoofed animals. Here we showed that p53 level was dynamically regulated during FMDV infection, being degraded at the early infection stage but recovered to the basal level at the late stage. Cells depleted of p53 showed inhibited FMDV replication and enhanced expression of the immune-related genes, whereas overexpression of p53 didn’t affect the viral replication. Viral challenge assay with p53 knockout mice obtained similar results, with viral load decreased, histopathological changes alleviated, and lifespan extended in the p53 knockout mice. Together, these data demonstrate that basal level p53 is required for efficient FMDV replication by suppressing the innate immunity