Autoencoder with Fitting Network for Terahertz Wireless Communications:A Deep Learning Approach

Terahertz wireless communication has been regarded as an emerging technology to satisfy the ever-increasing demand of ultra-high-speed wireless communications.However,affected by the imperfections of cheap and energy-efficient Terahertz devices,Terahertz signals suffer from serve hybrid distortions,including in-phase/quadrature imbalance,phase noise and nonlinearity,which degrade the demodulation performance significantly.To improve the robustness against these hybrid distortions,an improved autoencoder is proposed,which includes coding the transmitted symbols at the transmitter and decoding the corresponding signals at the receiver.Moreover,due to the lack of information of Terahertz channel during the training of the autoencoder,a fitting network is proposed to approximate the characteristics of Terahertz channel,which provides an approximation of the gradients of loss.Simulation results show that our proposed autoencoder with fitting network can recover the transmitted symbols under serious hybrid distortions,and improves the demodulation performance significantly.

家居智能制造过程中信息采集与处理技术的应用

随着工业4.0、中国制造2025的深化发展,家居行业逐步进入信息化、数字化、智能化的发展方向,信息采集与处理技术作为家居智能制造的基础技术,为家居行业深入智能化发展提供了信息化支撑。通过文献分析和企业实地调研,文中概述信息采集与处理技术的发展历程及其应用流程和技术架构;论述了家居智能制造过程中信息采集与处理的关键技术及其应用范畴,包括以条码技术、REID技术、机器视觉和OPC为主的信息采集技术以及以ERP、MES系统为核心的信息处理系统;针对现有家居企业信息采集与处理所存在的技术应用程度低、时效性差等问题,结合智能制造背景下信息集成、数字孪生、5G+工业互联网、人工智能技术在家居制造业中的实施和推广应用,从系统集成化、实时化、虚拟化、赋能化4个方面对家居智能制造过程中的信息采集与处理技术进行展望,以为家居行业信息化、智能化发展中更加有效利用信息提供借鉴和参考。

Hydrogel-supported poly(L-lactic acid) and polystyrene microsphere-based three-dimensional culture systems for in vitro cell expansion

The in vitro expansion of stem cells is important for their application in different life science fields such as cellular tissue and organ repair.An objective of this paper was to achieve static cell culture in vitro through peptide hydrogel-supported microspheres(MSs).The peptides,with their gel-forming properties,microstructures,and mechanical strengths characterized,were found to have good support for the MSs and to be injectable.The internal structures of poly(L-lactic acid)microspheres(PLLA-MSs)and polystyrene microspheres(PS-MSs)made in thelaboratory were observed and statistically analyzed in terms of particle size and pore size,following which the co-cultured MSs with cells were found to have good cell adhesion.In addition,three-dimensional(3D)culturing of cells was performed on the peptide and microcarrier composite scaffolds to measure cell viability and cell proliferation.The results showed that the peptides could be stimulated by the culture medium to self-assembly form a 3D fiber network structure.Under the peptide-Ms composite scaffold-based cell culture system,further enhancement of the cell culture effect was measured.The peptide-Ms composite scaffolds have great potential for the application in 3D cell culture and in vitro cellexpansion.

Three-dimensional domain swapping as a mechanism to lock the active conformation in a super-active octamer of SARS-CoV main protease

Proteolytic processing of viral polyproteins is indispensible for the lifecycle of coronaviruses.The main protease(M^(pro))of SARS-CoV is an attractive target for anti-SARS drug development as it is essential for the polyprotein processing.M^(pro) is initially produced as part of viral polyproteins and it is matured by autocleavage.Here,we report that,with the addition of an N-terminal extension peptide,M^(pro) can form a domain-swapped dimer.After complete removal of the extension peptide from the dimer,the mature M^(pro) self-assembles into a novel super-active octamer(AO-M^(pro)).The crystal structure of AO-M^(pro) adopts a novel fold with four domainswapped dimers packing into four active units with nearly identical conformation to that of the previously reported M^(pro) active dimer,and 3D domain swapping serves as a mechanism to lock the active conformation due to entanglement of polypeptide chains.Compared with the previously well characterized form of M^(pro),in equilibrium between inactive monomer and active dimer,the stable AO-M^(pro) exhibits much higher proteolytic activity at low concentration.As all eight active sites are bound with inhibitors,the polyvalent nature of the interaction between AO-M^(pro) and its polyprotein substrates with multiple cleavage sites,would make AO-M^(pro) functionally much more superior than the M^(pro) active dimer for polyprotein processing.Thus,during the initial period of SARS-CoV infection,this novel active form AOM^(pro) should play a major role in cleaving polyproteins as the protein level is extremely low.The discovery of AOM^(pro) provides new insights about the functional mechanism of M^(pro) and its maturation process.

Amphiphilic Dendrimer Vectors for RNA Delivery:State-of-the-Art and Future

Dendrimers,a special family of polymers,are particularly promising materials for various biomedical applications by virtue of their well-defined dendritic structure and cooperative multivalency.Specifically,in this Account,we present state-of-the-art amphiphilic dendrimers for nucleic acid delivery.Ribonucleic acid(RNA)molecules are fast becoming an important drug modality,particularly since the recent success of mRNA vaccines against COVID-19.Notably,RNA therapeutics offer the unique opportunity to treat diseases at the gene level and address“undruggable”targets.However,RNA therapeutics are not stable and have poor bioavailability,imposing the need for their protection and safe delivery by vectors to the sites-of-action to allow the desired therapeutic effects.Currently,the two most advanced nonviral vectors are based on lipids and polymers,with lipid vectors primarily exploiting the membrane-fusion mechanism and polymer vectors mainly endocytosis-mediated delivery.Notably,only lipid vectors have been advanced through to their clinical use in the delivery of,for example,the first siRNA drug and the first mRNA vaccine.The success of lipid vectors for RNA delivery has motivated research for further innovative materials as delivery vectors.Specifically,we have pioneered lipid/dendrimer conjugates,referred to as amphiphilic dendrimers,for siRNA delivery with the view to harnessing the delivery advantages of both lipid and polymer vectors while enjoying the unique structural features of dendrimers.These amphiphilic dendrimer vectors are lipid/dendrimer hybrids and are thus able to mimic lipid vectors and exploit membranefusion-mediated delivery,while simultaneously retaining the multivalent properties of polymer vectors that allow endocytosis-based delivery.In addition,they have precisely controllable and stable nanosized chemical structures and offer nanotechnology-based delivery.Effective amphiphilic dendrimer vectors share two important elements:chemical hydrophilic entities to bind RNA and RNA complex-stabilizing hydrophobicity.These two combined features allow the encapsulation of RNA within a stable complex before its release into the cytosol following endocytosis.This hydrophilic/hydrophobic balance permitted by the structural features of amphiphilic dendrimers plays a determining role in RNA delivery success.In this Account,we provide a conceptual overview of this exciting field with the latest breakthroughs and key advances in the design of amphiphilic dendrimers for the delivery of siRNA and mRNA.Specifically,we start with a short introduction to siRNA-and mRNA-based therapeutics and their delivery challenges.We then outline the pioneering and representative studies on amphiphilic dendrimer vectors to highlight their historical development and promising features that offer to facilitate the once challenging RNA delivery.We conclude by offering perspectives for the future of amphiphilic dendrimer vectors for nucleic acid delivery in general.

CD55 Variant Associated with Pegylated-interferonαTherapy Response in HBeAg-positive Chronic Hepatitis B Patients

Background and Aims:Only a small percentage of chronic hepatitis B(CHB)patients effectively respond to treatment with pegylated-interferon alpha(PegIFNα)or nucleos(t)ide analogues(NUCs).We aimed to detect the correlations of complement regulators-associated single-nucleotide polymorphisms(SNPs)with treatment response of hepatitis B e antigen(HBeAg)-positive CHB patients.Methods:A total of 1,763 HBeAg-positive CHB patients were enrolled,894 received PegIFNαfor at least 48 weeks and were followed up for 24 weeks,and 869 received NUCs for 104 weeks.For each patient,nine SNPs in genes encoding for complement regulators were determined and genotyped.To assess the cumulative effect of numerous SNPs,a polygenic score(PGS)was utilized.The correlations of SNPs and PGS with the levels of combined response(CR)and hepatitis B s antigen(HBsAg)loss were also investigated.Results:In PegIFNα-treated patients,an intronic SNP of CD55,rs28371597,was strongly related to CR,and the CR rate in rs28371597_GG genotype carriers was only approximately half that of rs28371597_GT/TT genotype carriers(20.29%vs.37.10%,p=2.00×10^(−3)).A PGS incorporating CD55_rs28371597 and two additional SNPs,CFB_rs12614 and STAT4_rs7574865,which had been considered as predictors for PegIFNαtreatment response before,was strongly correlated with the levels of CR(ptrend=7.94×10^(−6))and HBsAg loss(p-trend=9.40×10^(−3))in PegIFNα-treated patients.In NUCs-treated individuals,however,none of the nine SNPs were shown to be significantly linked to CHB treatment response.Conclusions:CD55_rs28371597 is a promising biomarker for predicting CHB patients’responsiveness to PegIFNαtherapy.The updated PGS may be used for optimizing CHB treatment.

Encapsulation of polyethylene glycol in cellulose-based porous capsules for latent heat storage and light-to-thermal conversion

Phase change materials are potential candidates for the application of latent heat storage.Herein,we fabricated porous capsules as shape-stable materials from cellulose-based polyelectrolyte complex,which were first prepared using cellulose 6-(N-pyridinium)hexanoyl ester as the cationic polyelectrolyte and carboxymethyl cellulose as the anionic polyelectrolyte to encapsulate polyethylene glycol by the vacuum impregnation method.Furthermore,the multi-walled carbon nanotube or graphene oxide,which were separately composited into the polyelectrolytes complex capsules to enhance thermal conductivity and light-to-thermal conversion efficiency.These capsules owned a typical core–shell structure,with an extremely high polyethylene glycol loading up to 34.33 g∙g^(‒1).After loading of polyethylene glycol,the resulted cellulose-based composite phase change materials exhibited high thermal energy storage ability with the latent heat up to 142.2 J∙g^(‒1),which was 98.5%of pure polyethylene glycol.Further results showed that the composite phase change materials demonstrated good form-stable property and thermal stability.Moreover,studies involving light-to-thermal conversion determined that composite phase change materials exhibited outstanding light-to-thermal conversion performance.Considering their exceptional comprehensive features,innovative composite phase change materials generated from cellulose presented a highly interesting choice for thermal management and renewable thermal energy storage.

Enhanced asymmetrically clipped DC biased optical OFDM for intensity-modulated direct-detection systems

In this paper,we propose an EADO-OFDM(Enhanced Asymmetrically Clipped DC Biased Optical Orthogonal Frequency Division Multiplexing)method for IM/DD(Intensity-Modulated DirectDetection)optical systems,in which the AV-DCO-OFDM(Absolute Valued DC Biased Optical OFDM)symbols on the even subcarriers and ACO-OFDM(Asymmetrically Clipped Optical OFDM)symbols on the odd subcarriers are combined for simultaneous transmission.Moreover,we discuss the PDF(Probability Density Function)and electrical SNR(Signal to Noise Ratio)of the symbols,which are utilized to estimate the BER(Bit Error Ratio)performance and overall performance of EADO-OFDM.The Monte Carlo simulation results have validated the theoretical analysis and have also confirmed the EADO-OFDM is attractive considering the following benefits.Firstly,EADO-OFDM is more energy efficient compared to the power-efficient DCO-OFDM(DC Biased Optical OFDM),since the required DC bias is smaller when appropriate constellation size combinations are chosen.In addition,EADO-OFDM performs better than the conventional ADO-OFDM(Asymmetrically Clipped DC Biased Optical OFDM),because the absolute value operation causes no clipping distortion.