Identification of a Printed Anti-Counterfeiting Code Based on Feature Guidance Double Pool Attention Networks

The authenticity identification of anti-counterfeiting codes based on mobile phone platforms is affected by lighting environment,photographing habits,camera resolution and other factors,resulting in poor collection quality of anti-counterfeiting codes and weak differentiation of anti-counterfeiting codes for high-quality counterfeits.Developing an anticounterfeiting code authentication algorithm based on mobile phones is of great commercial value.Although the existing algorithms developed based on special equipment can effectively identify forged anti-counterfeiting codes,the anti-counterfeiting code identification scheme based on mobile phones is still in its infancy.To address the small differences in texture features,low response speed and excessively large deep learning models used in mobile phone anti-counterfeiting and identification scenarios,we propose a feature-guided double pool attention network(FG-DPANet)to solve the reprinting forgery problem of printing anti-counterfeiting codes.To address the slight differences in texture features in high-quality reprinted anti-counterfeiting codes,we propose a feature guidance algorithm that creatively combines the texture features and the inherent noise feature of the scanner and printer introduced in the reprinting process to identify anti-counterfeiting code authenticity.The introduction of noise features effectively makes up for the small texture difference of high-quality anti-counterfeiting codes.The double pool attention network(DPANet)is a lightweight double pool attention residual network.Under the condition of ensuring detection accuracy,DPANet can simplify the network structure as much as possible,improve the network reasoning speed,and run better on mobile devices with low computing power.We conducted a series of experiments to evaluate the FG-DPANet proposed in this paper.Experimental results show that the proposed FG-DPANet can resist highquality and small-size anti-counterfeiting code reprint forgery.By comparing with the existing algorithm based on texture,it is shown that the proposed method has a higher authentication accuracy.Last but not least,the proposed scheme has been evaluated in the anti-counterfeiting code blurring scene,and the results show that our proposed method can well resist slight blurring of anti-counterfeiting images.

Active hyperspectral imaging with a supercontinuum laser source in the dark

An active hyperspectral imaging(HSI) system was built with a supercontinuum(SC) laser illuminator and a visible/near-infrared hyperspectral camera, which was used for object spectrum detection in the dark. It was demonstrated that the Gaussian-like distribution of the SC illuminator can still be used for accurate reflectance spectrum measurement once the illuminator was characterized in advance. The validity of active HSI results was demonstrated by comparison with passive results. Then, the active HSI system was used to acquire reflectance spectra of different objects in just one pushbroom measurement successfully. With algorithms of principal component analysis clustering and unsupervised K-means spectral classification, this active HSI system with high spectral and spatial resolutions was demonstrated to be efficient and applicable for specific spectrum detections.

Viral and nonviral nanocarriers for in vivo CRISPR-based gene editing

The continued development of clustered regularly interspaced short palindromic repeats(CRISPR)technology has the potential to greatly impact clinical medicine,particularly for disease diagnosis and treatment.Despite high demand for the in vivo delivery of CRISPR-based therapies,significant challenges persist.These include rapid degradation by enzymes,inefficient disease site targeting,and the risk of undesired off-target outcomes.Nanoparticulate platforms,with their tailorable properties,have been engineered to efficiently package CRISPR payloads in various formats,including as plasmid DNA,mRNA,and ribonucleoprotein complexes,for in vivo delivery.Among them,recombinant adeno-associated viruses,virus-like particles,and lipid nanoparticles have displayed exceptional promise.This review will discuss the development of these and other nanocarriers for in vivo CRISPR-based genome editing.

A genetically engineered neuronal membrane-based nanotoxoid elicits protective immunity against neurotoxins

Given their dangerous effects on the nervous system,neurotoxins represent a significant threat to public health.Various therapeutic approaches,including chelating agents,receptor decoys,and toxin-neutralizing antibodies,have been explored.While prophylactic vaccines are desirable,it is oftentimes difficult to effectively balance their safety and efficacy given the highly dangerous nature of neurotoxins.To address this,we report here on a nanovaccine against neurotoxins that leverages the detoxifying properties of cell membrane-coated nanoparticles.A genetically modified cell line with constitutive overexpression of theα7 nicotinic acetylcholine receptor is developed as a membrane source to generate biomimetic nanoparticles that can effectively and irreversibly bind toα-bungarotoxin,a model neurotoxin.This abrogates the biological activity of the toxin,enabling the resulting nanotoxoid to be safely delivered into the body and processed by the immune system.When co-administered with an immunological adjuvant,a strong humoral response againstα-bungarotoxin is generated that protects vaccinated mice against a lethal dose of the toxin.Overall,this work highlights the potential of using genetic modification strategies to develop nanotoxoid formulations against various biological threats.

Promotion effect of epoxy group neighboring single-atom Cu site on acetylene hydrochlorination

Carbon materials have been used as the support for catalysts in the field of acetylene hydrochlorination,the influence of inevitable oxygen-containing moieties on the reaction is often ignored and the mechanism of the oxygen-doping structure remains ambiguous.Herein,we explored the effect of the oxygen-containing group(C-O-C)in the support on the activity of single-atom dispersed Cu catalysts.By immersing the Cu single-atom catalyst in an alkaline solution,the epoxy species on the carbon support was cleaved to obtain a pure ether species while the Cu site was modified to a more electron-deficient state.The turnover frequency value of Cu/O-FLP catalyst with epoxy groups was 1.6-fold higher than that of alkaline treated catalyst.Our result indicated that the epoxy groups could assist adjacent single-atom Cu sites to synergistically promote the adsorption and cleavage of the reactant hydrogen chloride toward form C-OH and Cu-Cl bonds,and reduce the reaction energy barrier.The presence of electron deficient Cu sites and ether species could induce competitive adsorption of the acetylene and hydrogen chloride,thereby reducing the activity of the catalyst.This study highlights the influence of surface oxygen species and the tunability of the support,providing the foundation for the fabrication of higher-activity Cu catalysts for acetylene hydrochlorination.

Recent progress of iron-based electrocatalysts for nitrogen reduction reaction

Ammonia is a critical feedstock for modern industry and agriculture,which is also a promising carbonfree energy carrier.Electrochemical nitrogen reduction reaction(ENRR)is a sustainable and efficient approach to synthesize ammonia under ambient reaction conditions.ENRR relies on the development of highly efficient electrocatalysts.So far various strategies have been applied to enhance the performance of catalysts including tuning the electronic structure,binding strength,coordination configuration as well as the introduction of multiple active sites and defects.In this review,the recent progress of Fe-based electrocatalysts and their coordination effect,syner gistic effect and def ect effect for nitrogen reduction reaction have been summarized.Our critical review focuses on the discussion of theoretical advancement,the performance origin of ENRR activity and selectivity of Fe-based electrocatalysts.

The role of single-boron of N-doped graphene for effective nitrogen reduction

Room-temperature electrocatalytic nitrogen reduction reaction(NRR)is of paramount significance for the fertilizer industry and fundamental catalysis science.However,many NRR catalysts were based on the use of metals.Herein,we focus on exploring boron-based,metal-free,efficient catalysts for NRR by den-sity functional theory calculations with van der Waals corrections(DFT+D3).Our results show that the NRR performance of the boron active site can be improved by tuning the N-coordination environment in a graphene sheet,and the B-N-C structures show excellent stability.By considering the correlation be-tween the Bader charges of the boron dopant over N-decorated graphene and their NRR activities,the ra-tional design principle of a boron-based catalyst for NRR is developed.The boron-site with one pyridinic nitrogen in a double-vacancy structure is found to be a highly active center,with low reaction energy(0.53 eV)and kinetic barrier(0.84 eV)through the distal mechanism.We also found that the charge loss of boron considerably hampers hydrogen adsorption,which in turn promotes the NRR efficiency by hin-dering the competing hydrogen evolution.This work offers new insights into developing low-cost,highly effective boron-based materials as promising electrocatalysts for green ammonia synthesis.

Ultrafast Nonlinear Optical Excitation Behaviors of Mono-and Few-Layer Two Dimensional MoS2

The layered MoS2 has recently attracted significant attention for its excellent nonlinear optical properties.Here,the ultrafast nonlinear optical (NLO)absorption and excited carrier dynamics of layered MoS2(monolayer,3-4 layers,and 6-8 layers)are investigated via Z-scan and transient absorption spectra.Our experimental results reveal that NLO absorption coefficients of these MoS2 increase from-27×10^3cm/GW to -11×10^3cm/GW with more layers at 400-nm laser excitation,while the values decrease from 2.0×10^3cm/GW to 0.8×10^3cm/GW at 800nm.In addition, at high pump fluence,when the NLO response occurs,the results show that not only the reformation of the excitonic bands,but also the recovery time of NLO response decreases from 150ps to lOOps with an increasing number of layers,while the reductive energy of A excitonic band decreases from 191.TmeV to 51.1meV.The intriguing NLO response of MoS2 provides excellent potentials for the next-generation optoelectronic and photonic devices.