Tailoring Classical Conditioning Behavior in TiO_(2) Nanowires:ZnO QDs-Based Optoelectronic Memristors for Neuromorphic Hardware

Neuromorphic hardware equipped with associative learn-ing capabilities presents fascinating applications in the next generation of artificial intelligence.However,research into synaptic devices exhibiting complex associative learning behaviors is still nascent.Here,an optoelec-tronic memristor based on Ag/TiO_(2) Nanowires:ZnO Quantum dots/FTO was proposed and constructed to emulate the biological associative learning behaviors.Effective implementation of synaptic behaviors,including long and short-term plasticity,and learning-forgetting-relearning behaviors,were achieved in the device through the application of light and electrical stimuli.Leveraging the optoelectronic co-modulated characteristics,a simulation of neuromorphic computing was conducted,resulting in a handwriting digit recognition accuracy of 88.9%.Furthermore,a 3×7 memristor array was constructed,confirming its application in artificial visual memory.Most importantly,complex biological associative learning behaviors were emulated by mapping the light and electrical stimuli into conditioned and unconditioned stimuli,respectively.After training through associative pairs,reflexes could be triggered solely using light stimuli.Comprehen-sively,under specific optoelectronic signal applications,the four features of classical conditioning,namely acquisition,extinction,recovery,and generalization,were elegantly emulated.This work provides an optoelectronic memristor with associative behavior capabilities,offering a pathway for advancing brain-machine interfaces,autonomous robots,and machine self-learning in the future.

Effect of different concentrations of surfactant on the wettability of coal by molecular dynamics simulation

Anionic surfactant sodium dodecyl benzene sulfonate(SDBS)at varying concentrations was selected to investigate the influence on the wettability of Zhaozhuang Coal by molecular dynamics simulation.Six groups of water/surfactant/coal systems with different concentrations were constructed.The influence of surfactant with different concentrations on the wettability of coal was concluded by analyzing various properties from the energetic behaviors to the dynamic characteristics.The results show that the interfacial tension decreases sharply and then rises slowly with the increase of SDBS surfactant concentration,obtaining that surfactants can obviously reduce the interfacial tension.The surfactant molecules could be detected at the water/coal interface through analyzing the system’s relative concentration distribution.In addition,the difference in the wettability of surfactants on coal surfaces is caused by the spatial distribution differences of alkyl chains and the benzene ring of the surfactant molecules.And the negative interaction energy between SDBS and the coal surface indicates that adsorption process is spontaneous.Furthermore,it is of great practical significance for improving the dust reduction effect and reducing the disaster of coal dust by exploring the effects of surfactant molecules on the wettability of coal.

Advances in flexible sensors for intelligent perception system enhanced by artificial intelligence

Intelligent perception means that with the assistance of artificial intelligence(AI)-motivated brain,flexible sensors achieve the ability of memory,learning,judgment,and reasoning about external information like the human brain.Due to the superiority of machine learning(ML)algorithms in data processing and intelligent recognition,intelligent perception systems possess the ability to match or even surpass human perception systems.However,the built-in flexible sensors in these systems need to work on dynamic and irregular surfaces,inevitably affecting the precision and fidelity of the acquired data.In recent years,the strategy of introducing the developed functional materials and innovative structures into flexible sensors has made some progress toward the above challenges,and with the blessing of ML algorithms,accurate perception and reasoning in various scenarios have been achieved.Here,the most representative functional materials and innovative structures for constructing flexible sensors are comprehensively reviewed,the research progress of intelligent perception systems based on flexible sensors and ML algorithms is further summarized,and the intersection of the two is expected to unlock new opportunities for next-stage AI development.

Low-resolution optical transmission using joint shaping technique of signal probability and quantization noise

In this paper,we propose and experimentally demonstrate a joint shaping technique to improve the performance of a lowresolution transmission system for the first time,to the best of our knowledge.The joint shaping technique combines probabilistic shaping(PS)and error feedback noise shaping(EFNS).In the 40-Gbaud intensity-modulation direct-detection(IM/DD)experimental transmission system,a bit-error-rate(BER)of 3.8×10^(-3)can be achieved easily with the joint shaping at the physical number of bits(PNOB)of 3.In the 30-Gbaud dual polarization(DP)coherent experimental transmission system,a BER below 1×10^(-3)is easily obtained with a 3-bit quantizer by using joint shaping.The optimization of the shaping degree is also analyzed.

Diversity and independent evolutionary profiling of rodent-borne viruses in Hainan,a tropical island of China

The risk of emerging infectious diseases(EID)is increasing globally.More than 60%of EIDs worldwide are caused by animal-borne pathogens.This study aimed to characterize the virome,analyze the phylogenetic evolution,and determine the diversity of rodent-borne viruses in Hainan Province,China.We collected 682 anal and throat samples from rodents,combined them into 28 pools according to their species and location,and processed them for next-generation sequencing and bioinformatics analysis.The diverse viral contigs closely related to mammals were assigned to 22 viral families.Molecular clues of the important rodent-borne viruses were further identified by polymerase chain reaction for phylogenetic analysis and annotation of genetic characteristics such as arenavirus,coronavirus,astrovirus,pestivirus,parvovirus,and papillomavirus.We identified pestivirus and bocavirus in Leopoldoms edwardsi from Huangjinjiaoling,and bocavirus in Rattus andamanensis from the national nature reserves of Bangxi with low amino acid identity to known pathogens are proposed as the novel species,and their rodent hosts have not been previously reported to carry these viruses.These results expand our knowledge of viral classification and host range and suggest that there are highly diverse,undiscovered viruses that have evolved independently in their unique wildlife hosts in inaccessible areas.

Advanced polymer materials-based electronic skins for tactile and non-contact sensing applications

Recently,polymer materials have been at the forefront of other materials in building high-performance flexible electronic skin(e-skin)devices due to con-spicuous advantages including excellent mechanical flexibility,good compatibil-ity,and high plasticity.However,most research works just paid considerable attention and effort to the design,construction,and possible application of e-skins that reproduce the tactile perception of the human skin sensory system.Compared with tactile sensing devices,e-skins that aim to imitate the non-contact sensing features in the sensory system of human skin tend to avoid undesired issues such as bacteria spreading and mechanical wear.To further promote the development of e-skins to the human skin sensory system where tactile perception and non-contact sensing complement each other,significant progress and advances have been achieved in the field of polymer materials enabled e-skins for both tactile perception and non-contact sensing applications.In this review,the latest progress in polymer material-based e-skins with regard to tactile,non-contact sensing capabilities and their practical applications are introduced.The fabrication strategies of polymer materials and their role in building high-performance e-skins for tactile and non-contact sensing are highlighted.Furthermore,we also review the research works that integrated the polymer-based tactile and non-contact e-skins into robots and prostheses,smart gloves,and VR/AR devices and addressed some representative problems to dem-onstrate their suitability in practical applications in human–machine interac-tions.Finally,the current challenges in the construction of high-performance tactile and non-contact e-skins are highlighted and promising properties in this direction,by taking advantage of the polymer materials,are outlined.

High-speed multimode fiber imaging system based on conditional generative adversarial network

The multimode fiber(MMF)has great potential to transmit high-resolution images with less invasive methods in endoscopy due to its large number of spatial modes and small core diameter.However,spatial modes crosstalk will inevitably occur in MMFs,which makes the received images become speckles.A conditional generative adversarial network(GAN)composed of a generator and a discriminator was utilized to reconstruct the received speckles.We conduct an MMF imaging experimental system of transmitting over 1 m MMF with a 50μm core.Compared with the conventional method of U-net,this conditional GAN could reconstruct images with fewer training datasets to achieve the same performance and shows higher feature extraction capability.

Phylogenetic Analysis of the Dengue Virus Strains Causing the 2019 Dengue Fever Outbreak in Hainan,China

Dengue virus is an arthropod-borne pathogen that is transmitted to humans primarily by Aedes spp.mosquitos,causing the acute infectious disease,dengue fever(DF).Until 2019,no dengue outbreak had been reported in Hainan Province for over 20 years.However,in early September of 2019,an increasing number of infected cases appeared and the DF outbreak lasted for over one month in Haikou City,Hainan Province.In our study,we collected 97 plasma samples from DF patients at three hospitals,as well as 1585 mosquito larvae samples from puddles in different areas of Haikou.There were 49(50.5%)plasma samples found to be strongly positive and 9(9.3%)plasma samples were weakly positive against the NS1 antigen.We discovered DENV both in the patient's plasma samples and mosquito larvae samples,and isolated the virus from C6/36 cells inoculated with the acute phase serum of patients.Phylogenetic analysis revealed that the new strains were the most closely related to the epidemic strain in the southern regions of China,belonging to lineageⅣ,genotypeⅠ,DENV-1.Compared to the seven closest strains from neighboring countries and provinces,a total of 18 amino acid mutations occurred in the coding sequences(CDS)of the new isolated strain,DENV1 HMU-HKU-2.Our data shows that dengue virus is re-emerged in Hainan,and pose new threats for public health.Thus regular molecular epidemiological surveillance is necessary for control and prevention of DENV transmission.

Microwave photonics: radio-over-fiber links, systems, and applications [Invited]

Microwave photonics(MWPs)uses the strength of photonic techniques to generate,process,control,and distribute microwave signals,combining the advantages of microwaves and photonics.As one of the main topics of MWP,radio-over-fiber(RoF)links can provide features that are very difficult or even impossible to achieve with traditional technologies.Meanwhile,a considerable number of signal-processing subsystems have been carried out in the field of MWP as they are instrumental for the implementation of many functionalities.However,there are still several challenges in strengthening the performance of the technology to support systems and applications with more complex structures,multiple functionality,larger bandwidth,and larger processing capability.In this paper,we identify some of the notable challenges in MWP and review our recent work.Applications and future direction of research are also discussed.

A waterproof and breathable Cotton/rGO/CNT composite for constructing a layer-by-layer structured multifunctional flexible sensor

Developing a cotton fabric sensing layer with good waterproofness and breathability via a low-cost and eco-friendly method is increasingly important for the construction of comfortable and wearable electronic devices.Herein,a waterproof and breathable cotton fabric composite decorated by reduced graphene oxide(rGO)and carbon nanotube(CNT),Cotton/rGO/CNT,is reported by a facile solution infiltration method,and we adopt such Cotton/rGO/CNT composite to develop a layer-by-layer structured multifunctional flexible sensor,enabling the high-sensitivity detection of pressure and temperature stimulus.Particularly,the multifunctional flexible sensor exhibits a high response toward tiny pressure,demonstrating salient superiority in the continuous and reliable monitoring of human physiological information.Concerning temperature sensing,a good linear response for the temperatures ranging from 28 to 40℃ is achieved by the multifunctional flexible sensor and gives rise to be successfully applied to the non-contact real-time monitoring of human respiration signal.Finally,an array consisting of multifunctional flexible sensors further demonstrates its feasibility in perceiving and mapping the pressure and temperature information of contact objects.This work provides a feasible strategy for designing cotton-based sensing layers that can effectively resist liquid water penetration and allow water vapor transmission,and offers reasonable insight for constructing comfort and multifunctional wearable electronics.

Targeting papain-like protease for broad-spectrum coronavirus inhibition

The emergence of SARS-CoV-2 variants of concern and repeated outbreaks of coronavirus epidemics in the past two decades emphasize the need for next-generation pan-coronaviral therapeutics.Drugging the multi-functional papain-like protease(PLpro)domain of the viral nsp3 holds promise.However,none of the known coronavirus PLpro inhibitors has been shown to be in vivo active.Herein,we screened a structurally diverse library of 50,080 compounds for potential coronavirus PLpro inhibitors and identified a noncovalent lead inhibitor F0213 that has broad-spectrum anti-coronaviral activity,including against the Sarbecoviruses(SARSCoV-1 and SARS-CoV-2),Merbecovirus(MERS-CoV),as well as the Alphacoronavirus(hCoV-229E and hCoVOC43).Importantly,F0213 confers protection in both SARS-CoV-2-infected hamsters and MERS-CoV-infected human DPP4-knockin mice.F0213 possesses a dual therapeutic functionality that suppresses coronavirus replication via blocking viral polyprotein cleavage,as well as promoting antiviral immunity by antagonizing the PLpro deubiquitinase activity.Despite the significant difference of substrate recognition,mode of inhibition studies suggest that F0213 is a competitive inhibitor against SARS2-PLpro via binding with the 157K amino acid residue,whereas an allosteric inhibitor of MERSPLpro interacting with its 271E position.Our proof-ofconcept findings demonstrated that PLpro is a valid target for the development of broad-spectrum anticoronavirus agents.The orally administered F0213 may serve as a promising lead compound for combating the ongoing COVID-19 pandemic and future coronavirus outbreaks.

Genome Characteristics of the Cyclophragma Undans Nucleopolyhedrovirus: A Distinct Species in Group Ⅰ of Alphabaculovirus

The Cyclophragma undans nucleopolyhedrovirus （CyunNPV）, a potential pest control agent, was isolated from Cyclophragma undans （Lepidoptera： Lasiocampidae）, an important forest pest. In the present study, we performed detailed genome analysis of CyunNPV and compared its genome to those of other Group I alphabaculoviruses. Sequencing of the CyunNPV genome using the Roche 454 sequencing system generated 142,900 bp with a G ＋ C content of 45%. Genome analysis predicted a total of 147 hypothetical open reading frames comprising 38 baculoviral core genes, 24 lepidopteran baculovirus conserved genes, nine Group I Alphabaculovirus conserved genes, 71 common genes, and five genes that are unique to CyunNPV. In addition, the genome contains 13 homologous repeated sequences （hrs）. Phylogenetic analysis groups CyunNPV under a distinct branch within clade ＂a＂ of Group I in the genus Alphabaculovirus. Unlike other members of Group I, CyunNPV harbors only nine of the 11 genes previously determined to be specific to Group I viruses. Furthermore, the CyunNPV lacks the tyrosine phosphatase gene and the ac30 gene. The CyunNPV F-like protein contains two insertions of continuous polar amino acids, one at the conventional fusion peptide and a second insertion at the pretransmembrane domain. The insertions are likely to affect the fusion function and suggest an evolutionary process that led to inactivation of the F-like protein. The above findings imply that CyunNPV is a distinct species under Group I Alphabaculovirus.

Low-latency full-field temporal magnification based on spectral compression

Temporal magnification is an emerging technology for the observation of single-shot optical signals with irregular and ultrafast dynamics,which exceed the speed,precision,and record length of conventional digitizers.Conventional temporal magnification schemes suffer from transmission delay and large volume of dispersive elements.Because only the signal envelope can be magnified in the dispersion-based schemes,real-time full-field(phase and amplitude)measurement for a complex ultrafast optical signal remains an open challenge.Here,a bandwidth-compressed temporal magnification scheme for low-latency full-field measurements of ultrafast dynamics is proposed.Unlike the dispersion-based schemes,temporal magnification of a complex optical signal is achieved by bandwidth compression.The bandwidth is coherently compressed by the Vernier effect relying on the detuned free spectral range of a periodic optical filter and time lens.Experimentally,a temporal magnification factor of 224 is realized,and full-field measurements for picosecond pulses are demonstrated.The proposal eliminates the dependence on dispersive elements and shows great potential in integration,which may pave a new path toward full-field measurement for nonrepetitive and statistically rare signals.

Characterization of the viral fibroblast growth factor homolog of Helicoverpa armigera single nucleopolyhedrovirus

Fibroblast growth factor(FGF) is found throughout multicellular organisms; however, fgf homologs(vfgf) have only been identified among viruses in lepidopteran baculoviruses. The function of v FGFs from Group I alphabaculoviruses, including Autographa californica multiple nucleopolyhedrovirus(Ac MNPV) and Bombyx mori nucleopolyhedrovirus(Bm NPV), involves accelerated killing of infected larvae by both viruses. The v FGF of Group II alphabaculovirus is structurally different from that of Group I alphabaculovirus, with a larger C-terminal region and additional N-linked glycosylation sites. In this study, we characterized the Group II alphabaculovirus v FGF of Helicoverpa armigera single nucleopolyhedrovirus(Hear NPV). The transcription and expression of vfgf was detected at 3 h and 16 h post-infection in Hear NPV-infected cells. To further study v FGF function, we constructed vfgf-knockout and-repaired Hear NPV bacmids and investigated their affect in both cultured cells and insects. Deletion of vfgf had no effect on budded-virus production or viral DNA replication in cultured Hz AM1 cells. However, bioassays showed that Hear NPV vfgf deletion significantly increased the median lethal dose and delayed the median lethal time by ~12 h in the host insect when the virus was delivered orally. These results suggested that v FGF is an important virulent factor for HearN PV infection and propagation in vivo.