Self-supervised recalibration network for person re-identification

The attention mechanism can extract salient features in images,which has been proved to be effective in improving the performance of person re-identification(Re-ID).However,most of the existing attention modules have the following two shortcomings:On the one hand,they mostly use global average pooling to generate context descriptors,without highlighting the guiding role of salient information on descriptor generation,resulting in insufficient ability of the final generated attention mask representation;On the other hand,the design of most attention modules is complicated,which greatly increases the computational cost of the model.To solve these problems,this paper proposes an attention module called self-supervised recalibration(SR)block,which introduces both global and local information through adaptive weighted fusion to generate a more refined attention mask.In particular,a special"Squeeze-Excitation"(SE)unit is designed in the SR block to further process the generated intermediate masks,both for nonlinearizations of the features and for constraint of the resulting computation by controlling the number of channels.Furthermore,we combine the most commonly used Res Net-50 to construct the instantiation model of the SR block,and verify its effectiveness on multiple Re-ID datasets,especially the mean Average Precision(m AP)on the Occluded-Duke dataset exceeds the state-of-the-art(SOTA)algorithm by 4.49%.

Binary Program Vulnerability Mining Based on Neural Network

Software security analysts typically only have access to the executable program and cannot directly access the source code of the program.This poses significant challenges to security analysis.While it is crucial to identify vulnerabilities in such non-source code programs,there exists a limited set of generalized tools due to the low versatility of current vulnerability mining methods.However,these tools suffer from some shortcomings.In terms of targeted fuzzing,the path searching for target points is not streamlined enough,and the completely random testing leads to an excessively large search space.Additionally,when it comes to code similarity analysis,there are issues with incomplete code feature extraction,which may result in information loss.In this paper,we propose a cross-platform and cross-architecture approach to exploit vulnerabilities using neural network obfuscation techniques.By leveraging the Angr framework,a deobfuscation technique is introduced,along with the adoption of a VEX-IR-based intermediate language conversion method.This combination allows for the unified handling of binary programs across various architectures,compilers,and compilation options.Subsequently,binary programs are processed to extract multi-level spatial features using a combination of a skip-gram model with self-attention mechanism and a bidirectional Long Short-Term Memory(LSTM)network.Finally,the graph embedding network is utilized to evaluate the similarity of program functionalities.Based on these similarity scores,a target function is determined,and symbolic execution is applied to solve the target function.The solved content serves as the initial seed for targeted fuzzing.The binary program is processed by using the de-obfuscation technique and intermediate language transformation method,and then the similarity of program functions is evaluated by using a graph embedding network,and symbolic execution is performed based on these similarity scores.This approach facilitates cross-architecture analysis of executable programs without their source codes and concurrently reduces the risk of symbolic execution path explosion.

Bioinspired Adaptive,Elastic,and Conductive Graphene Structured Thin-Films Achieving High-Efficiency Underwater Detection and Vibration Perception

Underwater exploration has been an attractive topic for understanding the very nature of the lakes and even deep oceans.In recent years,extensive efforts have been devoted to developing functional materials and their integrated devices for underwater information capturing.However,there still remains a great challenge for water depth detection and vibration monitoring in a high-efficient,controllable,and scalable way.Inspired by the lateral line of fish that can sensitively sense the water depth and environmental stimuli,an ultrathin,elastic,and adaptive underwater sensor based on Ecoflex matrix with embedded assembled graphene sheets is fabricated.The graphene structured thin film is endowed with favourable adaptive and morphable features,which can conformally adhere to the structural surface and transform to a bulged state driven by water pressure.Owing to the introduction of the graphene-based layer,the integrated sensing system can actively detect the water depth with a wide range of 0.3-1.8 m.Furthermore,similar to the fish,the mechanical stimuli from land(e.g.knocking,stomping)and water(e.g.wind blowing,raining,fishing)can also be sensitively captured in real time.This graphene structured thin-film system is expected to demonstrate significant potentials in underwater monitoring,communication,and risk avoidance.

Recent advances in breathable electronics

The successful implementation of bioelectronic devices attached to living organism hinges on a number of material and device characteristics,including not only electrical and mechanical performances to gather physiological signals from living organism thus enabling status monitoring,but also permeability or breathability for gas/nutrient exchange between living organisms and surroundings to ensure minimum perturbation of the intrinsic biological function.However,most bioelectronic devices built on planar polymeric substrates,such as polydimethylsiloxane(PDMS),polyurethane(PU),and polyimide(PI),lack efficient gas permeability,which may hinder the emission of volatile compounds from the surface of living organism,affecting the natural metabolism and reducing the comfort of wearing.Thus,achieving permeability or breathability in bioelectronic devices is a significant challenge.Currently,the devices made of gas-permeable materials with porous structures,that combine electronic components with daily garments,such as fibric and textile,offer exciting opportunities for breathable electronics.In this review,several types of gas-permeable materials with their synthesis and processing routes are outlines.Then,two methods for measuring water vapor transmission rate of materials are discussed in depth.Finally,recent progress in the use of gaspermeable materials for the applications of plant-and skin-attached electronics is summarized systematically.

Mechanochemical transformation of fluorescent hydrogel based on dynamic lanthanide-terpyridine coordination

As a burgeoning research field, ultrasound-responsive materials have attracted intense interest in healthcare research. However, the basic mechanism of sonochemical effect in the quasi-solid state is far from being well understood than those in the solution. Herein, we showcase mechanochemical transformations of europium(Ⅲ) complexes in a supramolecular hydrogel matrix. With the combination of labile terpyridine-europium complexes(TPY-Eu^(3+)) as mechanochromic moieties and an ultrasound-responsive fluorogen(URF) as a molecular tweezer, the hydrogel produces a notable fluorescence change in response to ultrasound. The mechanochemical transformation was elucidated by molecular dynamics(MD) simulations, and fully probed and evidenced by electrochemical experiments, X-ray photoelectron spectroscopy(XPS), and attenuated total reflectance-Fourier transform infrared(ATR-FTIR) spectroscopy.

Ultralong excimer phosphorescence by the self-assembly and confinement of terpyridine derivatives in polymeric matrices

Ultralong organic room temperature phosphorescence(RTP)is attracting increas-ing attention due to its fascinating optical phenomena and wide applications.Among various RTP,excimer phosphorescence is of fundamental significance,but it remains a considerable challenge to achieveflexible,multicolor and large-area excimer RTP materials,which should greatly advance the understanding and devel-opment of organic light-emitting devices.Herein,we present ultralong excimer RTPfilms by the self-assembly and confinement of terpyridine(Tpy)derivatives in polymeric matrices.Strikingly,the self-assembly of Tpy derivatives induces the formation of excimer complexes,thus immensely minimizing singlet-triplet split-ting energy(ΔEST)to promote the intersystem crossing process.Furthermore,the confinement by multiple hydrogen bonding interactions as well as the compact aggregation of phosphors jointly suppresses the nonradiative transitions,leading to long-lived excimer RTP(τ543.9 ms,19,000-fold improvements over the pow-=der).On account of the outstanding afterglow performance and color-tunability of RTP materials,flexible and large-areafilms were fabricated for intelligent display,anticounterfeiting,and time-resolved information encryption.

Fluorescent Organohydrogel with Thermal-Induced Color Change for Anti-counterfeiting

Smart fluorescent patterns enable dynamic color variation under external stimuli,showing a much higher security level in the field of anti-counterfeiting.However,there is still lacking of a simple and convenient way to achieve dynamic fluorescence changes.Herein,a fluorescent organohydrogel made up of a poly(N,/N-dimethylacrylamide-co-isopropylacrylamide)(p(DMA-NIPAM))hydrogel network and a polyflauryl methacrylate)(PLMA)organogel network was fabricated via a two-step interpenetrating technique.The former network bears naphthalimide moieties(DEAN,green fluorescent monomer)and the later contains 6-acrylamidopicolinic acid(6APA,fluorescent ligand),leading to emitting green fluorescence.When Eu^(3+) was introduced and coordinated with 6APA,the organohydrogel displays red fluorescence,which can further emit yellow after applying thermal stimulus.Furthermore,by adjusting the proportion of comonomers,various organohydrogels can be obtained,which can be programmed and act as an effective platform for the encryption and decryption of secret information.

Fabrication of Neutral Supramolecular Polymeric Films via Post-electropolymerization of Discrete Metallacycles

Self-assembly post-modification has proven to be an efficient strategy to build higher-order supramolecular architectures and functional materials. In this study, we successfully realized the construction＇of a new family of neutral supramolecular polymeric films containing well-defined metallacycles as the main scaffolds through combination Of coordination-driven self-assembly with post-electropolymerization. The obtained neutral polymeric materials were fully characterized by the cyclic voltammogram （CV）, SEM, and TEM. The thickness of the films was able to be well regulated by the number of scanning cycles. Moreover, we found that the shape of the metallacycles and the number of triphenylamine moieties played important roles in the formation of the final polymer films. We believe that the introduction of the neutral metallacycles into the final polymer structures not only enriches the library of supramolecular polymeric films but also provides a new platform to study neutral molecule detection, separation, and capture.

Construction of Highly Emissive Pt(Ⅱ) Metallacycles upon Irradiation

Photoswitchable or photoactivatable fluorescent species have been found wide applications within supramolecular chemistry and materials science.In this study,we successfully constructed two highly emissive Pt(Ⅱ)metallacycles from the diarylethene ligands via coordination-driven self-assembly.Different from the most known fluorescent metallacycles,the obtained metallacycles have displayed"turn-on"fluorescence switching.They are non-fluorescent in solution,but they emit highly yellow or orange fluorescence under ultraviolet irradiation.The metallacycles were well characterized by 1H NMR,31P NMR and ESI-TOF-MS.The photochromic properties of the resultant metallacycles were investigated by 1H NMR,31P NMR,UV/Vis spectrum and fluorescence spectrum.Notably,NMR studies revealed that these two metallacycles featured excellent cyclization efficiency(90% conversion efficiency).Moreover,the closed-ring isomers of the metallacycles displayed relatively high quantum yield(ФF=0.5).DFT simulations demonstrated that the antiparallel configuration of the diarylethene ligand had an angle closed to 120°,which was more stable in energy compared to the parallel configuration,thus allowing for the facile construction of highly emissive metallacycles.We believe that such highly emissive metallacycles which are in-situ prepared upon irradiation can be used as new fluorescence materials for sensing and bioimaging in the future.

A Near-Infrared Organoplatinum(Ⅱ) Metallacycle Conjugated with Heptamethine Cyanine for Trimodal Cancer Therapy

Discrete Pt(Ⅱ)metallacycles have attracted particular attention for the chemotherapeutic treatment of cancer.However,a single chemotherapy cannot simultaneously balance efficiency and safety because the continuous administration throughout the entire therapy period will lead to inefficient therapy and potentially long-term systemic toxicity.Therefore,the development of a novel organoplatinum(Ⅱ)metallacycle with multimodal treatment capabilities is urgently needed to overcome these issues.Herein,a discrete Pt(II)metallacycle(SCY)bearing the near-infrared(NIR)photosensitizer heptamethine cyanine was fabricated and further encapsulated by amphiphilic 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy(polyethyleneglycol)(DSPEmPEG)to form P@SCY nanoparticles.Heptamethine cyanine,which has excellent photoconversion efficiency,can generate reactive oxygen species(ROS)and heat simultaneously,and the cyanine moiety can target mitochondria in cancer cells due to their quaternary ammonium salt cations,which improve the effect of phototherapy.Due to its excellent phototherapy and chemotherapy properties,P@SCY exhibited remarkable trimodal therapeutic effects[chemo-/photodynamic therapy(PDT)/photothermal therapy(PTT)]against cancer cells(HepG2 cells,MCF-7 cells,and 4T1 cells)in vitro.Furthermore,in vivo results also confirmed thatP@SCY had superior antitumor properties with minimal side effects in the 4T1 tumor model.Thiswork presents a practicable approach to develop a multifunctional organoplatinum(Ⅱ)metallacycle for multimodal tumor therapy.

Progress in aggregation-induced emission-active fluorescent polymeric hydrogels

Aggregation-induced emission(AIE)-active fluorescent polymeric hydrogels(FPHs)are the marriage of AIE-active materials and polymeric hydrogels.Different from the widely studied AIE-active materials that are primarily used in solution or dry solid state,they feature a three-dimensional crosslinked polymer network that can absorb water without dissolving.Consequently,they are known to bear many advantageous properties such as soft wet nature,tissue-like mechanical strength,biocompatibility,biomimetic self-healing feature,facilely tailored structure,as well as responsive fluorescence and volume/shape changes,thus representing a promising category of luminescent materials with many frontier uses.This Review is intended to give a systematic summary of the recent progress in this young but flourishing research area,with particular focus on their design and preparation.Current challenges and future outlooks in this field are also discussed in order to attract new interests and inspire more efforts.