24 research outputs found
One-to-Many Semantic Communication Systems: Design, Implementation, Performance Evaluation
Semantic communication in the 6G era has been deemed a promising
communication paradigm to break through the bottleneck of traditional
communications. However, its applications for the multi-user scenario,
especially the broadcasting case, remain under-explored. To effectively exploit
the benefits enabled by semantic communication, in this paper, we propose a
one-to-many semantic communication system. Specifically, we propose a deep
neural network (DNN) enabled semantic communication system called MR\_DeepSC.
By leveraging semantic features for different users, a semantic recognizer
based on the pre-trained model, i.e., DistilBERT, is built to distinguish
different users. Furthermore, the transfer learning is adopted to speed up the
training of new receiver networks. Simulation results demonstrate that the
proposed MR\_DeepSC can achieve the best performance in terms of BLEU score
than the other benchmarks under different channel conditions, especially in the
low signal-to-noise ratio (SNR) regime.Comment: 5 pages, 6 figures, published to C
Biodegradable double-network GelMA-ACNM hydrogel microneedles for transdermal drug delivery
As a minimally invasive drug delivery platform, microneedles (MNs) overcome many drawbacks of the conventional transdermal drug delivery systems, therefore are favorable in biomedical applications. Microneedles with a combined burst and sustained release profile and maintained therapeutic molecular bioactivity could further broaden its applications as therapeutics. Here, we developed a double-network microneedles (DN MNs) based on gelatin methacrylate and acellular neural matrix (GelMA-ACNM). ACNM could function as an early drug release matrix, whereas the addition of GelMA facilitates sustained drug release. In particular, the double-network microneedles comprising GelMA-ACNM hydrogel has distinctive biological features in maintaining drug activity to meet the needs of application in treating different diseases. In this study, we prepared the double-network microneedles and evaluated its morphology, mechanical properties, drug release properties and biocompatibility, which shows great potential for delivery of therapeutic molecules that needs different release profiles in transdermal treatment
TencentPretrain: A Scalable and Flexible Toolkit for Pre-training Models of Different Modalities
Recently, the success of pre-training in text domain has been fully extended
to vision, audio, and cross-modal scenarios. The proposed pre-training models
of different modalities are showing a rising trend of homogeneity in their
model structures, which brings the opportunity to implement different
pre-training models within a uniform framework. In this paper, we present
TencentPretrain, a toolkit supporting pre-training models of different
modalities. The core feature of TencentPretrain is the modular design. The
toolkit uniformly divides pre-training models into 5 components: embedding,
encoder, target embedding, decoder, and target. As almost all of common modules
are provided in each component, users can choose the desired modules from
different components to build a complete pre-training model. The modular design
enables users to efficiently reproduce existing pre-training models or build
brand-new one. We test the toolkit on text, vision, and audio benchmarks and
show that it can match the performance of the original implementations
The Qitai Radio Telescope
This study presents a general outline of the Qitai radio telescope (QTT)
project. Qitai, the site of the telescope, is a county of Xinjiang Uygur
Autonomous Region of China, located in the east Tianshan Mountains at an
elevation of about 1800 m. The QTT is a fully steerable, Gregorian type
telescope with a standard parabolic main reflector of 110 m diameter. The QTT
has adopted an um-brella support, homology-symmetric lightweight design. The
main reflector is active so that the deformation caused by gravity can be
corrected. The structural design aims to ultimately allow high-sensitivity
observations from 150 MHz up to 115 GHz. To satisfy the requirements for early
scientific goals, the QTT will be equipped with ultra-wideband receivers and
large field-of-view mul-ti-beam receivers. A multi-function signal-processing
system based on RFSoC and GPU processor chips will be developed. These will
enable the QTT to operate in pulsar, spectral line, continuum and Very Long
Baseline Interferometer (VLBI) observing modes. Electromagnetic compatibility
(EMC) and radio frequency interference (RFI) control techniques are adopted
throughout the system design. The QTT will form a world-class observational
platform for the detection of low-frequency (nanoHertz) gravitational waves
through pulsar timing array (PTA) techniques, pulsar surveys, the discovery of
binary black-hole systems, and exploring dark matter and the origin of life in
the universe.Comment: 12 pages, 11 figures, accepted for publication in Science China
Physics, Mechanics & Astronom
MicroRNA-21 regulates breast cancer invasion partly by targeting tissue inhibitor of metalloproteinase 3 expression
<p>Abstract</p> <p>Background</p> <p>MicroRNAs are non-coding RNA molecules that posttranscriptionally regulate expression of target genes and have been implicated in the progress of cancer proliferation, differentiation and apoptosis. The aim of this study was to determine whether microRNA-21 (miR-21), a specific microRNA implicated in multiple aspects of carcinogenesis, impacts breast cancer invasion by regulating the tissue inhibitor of metalloproteinase 3 (TIMP3) gene.</p> <p>Methods</p> <p>miR-21 expression was investigated in 32 matched breast cancer and normal breast tissues, and in four human breast cancer cell lines, by Taqman quantitative real-time PCR. Cell invasive ability was determined by matrigel invasion assay in vitro, in cells transfected with miR-21 or anti-miR-21 oligonucleotides. In addition, the regulation of tissue inhibitor of metalloproteinase 3 (TIMP3) by miR-21 was evaluated by western blotting and luciferase assays.</p> <p>Results</p> <p>Of the 32 paired samples analyzed, 25 breast cancer tissues displayed overexpression of miR-21 in comparison with matched normal breast epithelium. Additionally, incidence of lymph node metastasis closely correlated with miR-21 expression, suggesting a role for miR-21 in metastasis. Similarly, each of the four breast cancer cell lines analyzed overexpressed miR-21, to varied levels. Further, cells transfected with miR-21 showed significantly increased matrigel invasion compared with control cells, whereas transfection with anti-miR-21 significantly decreased cell invasion. Evaluation of TIMP3 protein levels, a peptidase involved in extarcellular matrix degredation, inversely correlated with miR-21 expression.</p> <p>Conclusion</p> <p>As knockdown of miR-21 increased TIMP3 protein expression and luciferase reporter activity, our data suggests that miR-21 could promote invasion in breast cancer cells via its regulation of TIMP3.</p
Electrospun Fibers Derived from Peptide Coupled Amphiphilic Copolymers for Dorsal Root Ganglion (DRG) Outgrowth
Developing scaffolds with appropriate mechanical/structural features as well as tunable bioactivities are indispensable in the field of tissue engineering. This study focused on one such attempt to electrospin the copolymer of L-lactic acid (L-LA) and functional monomer (3(S)- [(benzyloxycarbony)methyl]-1,4-dioxane-2,5-dione, BMD) with small peptide modifications for the purpose of neural tissue engineering. Scanning Electron Microscopy (SEM) micrographs showed fabricated electrospun copolymer as porous and uniform nanofibrous materials with diameter in the range of 800â1000 nm. In addition, the modified scaffolds displayed a lower contact angle than poly(L-lactide) (PLLA) indicating higher hydrophilicity. To further incorporate the bioactive functions, the nanofibers were chemically coupled with small peptide (isoleucine-lysine-valine-alanine-valine, IKVAV). The incorporation of IKVAV onto the electrospun fiber was confirmed by X-ray photoelectron spectroscopy (XPS) and such incorporation did not affect the surface morphology or fiber diameters. To demonstrate the potential of applying the designed scaffolds for nerve regeneration, dorsal root ganglion (DRG) neurons were cultured on the nanofibers to examine the impact on neurite outgrowth of DRGs. The results indicated that the fabricated nanofibrous matrix with small peptide might be a potential candidate for neural tissue engineering
DBD Plasma Combined with Different Foam Metal Electrodes for CO2 Decomposition: Experimental Results and DFT Validations
In the last few years, due to the large amount of greenhouse gas emissions causing environmental issue like global warming, methods for the full consumption and utilization of greenhouse gases such as carbon dioxide (CO2) have attracted great attention. In this study, a packed-bed dielectric barrier discharge (DBD) coaxial reactor has been developed and applied to split CO2 into industrial fuel carbon monoxide (CO). Different packing materials (foam Fe, Al, and Ti) were placed into the discharge gap of the DBD reactor, and then CO2 conversion was investigated. The effects of power, flow velocity, and other discharge characteristics of CO2 conversion were studied to understand the influence of the filling catalysts on CO2 splitting. Experimental results showed that the filling of foam metals in the reactor caused changes in discharge characteristics and discharge patterns, from the original filamentary discharge to the current filamentary discharge as well as surface discharge. Compared with the maximum CO2 conversion of 21.15% and energy efficiency of 3.92% in the reaction tube without the foam metal materials, a maximum CO2 decomposition rate of 44.84%, 44.02%, and 46.61% and energy efficiency of 6.86%, 6.19%, and 8.85% were obtained in the reaction tubes packed with foam Fe, Al, and Ti, respectively. The CO2 conversion rate for reaction tubes filled with the foam metal materials was clearly enhanced compared to the non-packed tubes. It could be seen that the foam Ti had the best CO2 decomposition rate among the three foam metals. Furthermore, we used density functional theory to further verify the experimental results. The results indicated that CO2 adsorption had a lower activation energy barrier on the foam Ti surface. The theoretical calculation was consistent with the experimental results, which better explain the mechanism of CO2 decomposition