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The key generation rate (KGR) of physical layer key generation (PLKG) is severely restricted in quasi-static environments due to a lack of entropy. To address the problem, a reconfigurable intelligent surface (RIS) is introduced. In this letter, we consider the design of phase shift matrix with vector quantization to fully exploit the randomness of the RIS. In order to reduce the bit disagreement ratio (BDR), we design a vector quantizer to fully exploit the quantization range of the RIS channel. Additionally, we provide the design strategy for the phase shift matrix that aligns with the vector quantizer. Furthermore, we present a closed-form solution for the phase shift matrix. Meanwhile, to balance the tradeoff between high KGR and low BDR, we calculate the BDR in different quantization orders and propose an adaptive quantization order selection. Simulations validate that our proposed scheme obtain a higher KGR than the existing schemes under a certain BDR threshold.

The photocatalytic reduction of CO2with H2O into valuable chemicals is a sustainable carbon-neutral technology for renewable energy; however, the photocatalytic activity and product selectivity remain challenging. Herein, an S-scheme heterojunction photocatalyst with superior CO2photoreduction performance─porous C3N4(CN) nanosheets anchored with zinc(II) tetra(4-cyanophenyl)porphyrin (ZnTP) nanoassemblies (denoted as ZnTP/CN)─was designed and prepared via a simple self-assembly process. The constructed ZnTP/CN heterojunction had rich accessible active sites, improved CO2absorption capacity, and high charge carrier separation efficiency caused by the S-scheme heterojunction. As a result, the obtained ZnTP/CN catalyst exhibited considerable activity for photocatalytic CO2reduction, yielding CO with a generation rate of 19.4 μmol g–1·h–1and a high selectivity of 95.8%, which is much higher than that of pristine CN nanosheets (4.53 μmol g–1·h–1, 57.4%). In addition, theoretical calculations and in situ Fourier transform infrared spectra demonstrated that the Zn sites in the porphyrin unit favor CO2activation and *COOH formation as well as CO desorption, thereby affording a high CO selectivity. This work provides insight into the design and fabrication of efficient S-scheme heterostructure photocatalysts for solar energy storage.

We have developed a formal [4+2] cycloaddition reaction of N-fluorobenzamides and maleic anhydride in the presence of CuI and LiOH, and a series of fluorescent 1-amino-2,3-naphthalic anhydrides were produced in good yields. This reaction proceeded via a multistep process involving nitrogen-centered radical generation, 1,5-hydrogen atom transfer, and benzylic radical addition to the amide carbonyl oxygen to generate an N-(tert-butyl) isobenzofuran-1(3H)-imine intermediate, which isomerized to an N-(tert-butyl) isobenzofuran-1-amine via deprotonation and protonation with the aid of LiOH; finally, the amine underwent a [4+2] cycloaddition reaction with maleic anhydride to give the 1-amino-2,3-naphthalic anhydride product upon dehydrating aromatization. Notably, the corresponding naphthalic anhydride products could be transformed into a diverse array of naphthalimides. Both the naphthalic anhydrides and the naphthalimides exhibited similar fluorescent features.

The one-time pad (OTP) is an application-layer encryption technique to achieve the information-theoretic security, and the physical-layer secret key generation (SKG) technique is a promising candidate to provide the random keys for OTP. In this paper, we propose a joint SKG and OTP encryption scheme with the aid of a reconfigurable intelligent surface (RIS) to boost secret key rate. To maximize the efficiency of secure communication, we divide the process of secure transmission into two stages: SKG and then encrypted packet transmission. Meanwhile, we design an optimal algorithm for allocating time slots for SKG to maximize SKG efficiency without security risk. Furthermore, we design a key updating protocol based on our SKG scheme for OTP encryption. Simulation results verify that our scheme can generate keys securely and efficiently, and significantly improve the secure communication performance in an intelligent IoT system.

Introduction:Virus-like particles (VLPs), self-assembled multiprotein structures, can stimulate robust immune responses due to their structural similarity to native virions that allow the presentation of multiple copies of the target epitopes. Utilizing VLPs as vaccine platforms to present exogenous antigens is a promising and challenging approach in the vaccine development field. This study investigates the potential of the truncated hepatitis E virus (HEV) capsid as a VLP platform to present foreign antigens. Methods:The S and M domains of the HEV capsid protein were selected as the optimal carrier (CaSM). The exogenous antigen Seq8 containing 3 neutralizing epitopes from 3 different foot-and-mouth disease virus (FMDV) strains was linked to the C-terminal of CaSM to construct a chimeric VLP (CaSM-Seq8). The chimeric particles were produced in Escherichia coli, and their morphology, physicochemical properties, antigenicity, and immunogenicity were analyzed. Results:Morphological analysis showed that CaSM-Seq8 self-assembled into VLPs similar to CaSM VLPs (∼26 nm in diameter) but smaller than native HEV virions. Further, the thermal stability and the resistance to enzymatic proteolysis of Seq8 were enhanced when it was attached to the CaSM carrier. The antigenicity analysis revealed a more robust reactivity against anti-FMDV antibodies when Seq8 was presented on CaSM particles. Upon injection into mice, FMDV-specific IgGs induced by CaSM-Seq8 appeared earlier, increased faster, and maintained higher levels for a longer time than those induced by Seq8 alone or the inactivated FMDV vaccine. Conclusion:This study demonstrated the potential of utilizing the truncated HEV capsid as an antigen-presenting platform for the development of chimeric VLP immunogens.

The direct/aerodynamic force compound control can enhance the maneuverability and response characteristics of missiles, and the dynamic stabilization is the precondition of normal operation for rolling missiles. Aiming at the stability problem caused by the cross-coupling effect of rolling missiles employing direct/aerodynamic force compound control, proposing a typical topological control system structure described by the complex coefficient theory, and deducing the dynamic stability conditions. Firstly, the mathematic model is established based on the kinematics and dynamics theories of rotating airframes and the direct/aerodynamic force compound control mechanism. Then, a three-loop autopilot and the direct/aerodynamic force ratio distribution method are designed to establish the complex summation model of the compound control system by selecting suitable complex variables. Furthermore, deducing the dynamic stability conditions and verifying them by numerical simulations. Finally, the stable regions of the rolling missile in different cases are obtained and found to be influenced by many factors, such as parameters of the autopilot, hybrid force distribution proportion and rolling rate. The derived dynamic stability criterion is effective for evaluating the stability of rolling missiles employing direct/aerodynamic force compound control and the research method used in this paper can provide reference for the stability study of strongly coupled nonlinear systems.

The performance of high-speed steel (HSS) powder is a prerequisite for the preparation of high-performance powder metallurgy HSS. The physical properties, microstructure, and solidification characteristics of HSS powder prepared by nitrogen gas atomisation were systematically studied and analysed in detail. For the atomised TPM558 HSS powder, the morphology is spherical and the particle size distribution is wide. The smooth small particles of satellite powder attach to the surface of large particles. Shrinkage pits caused by solidification shrinkage exist on the surface of large particles. The average cooling rate is between 104and 106K·s−1, with the increase of cooling rate, the powder surface tends to be smooth, and the grain structure is transformed in the order of cellular to dendritic to radial. The single powder particle surface shows fine-equiaxed grains, while the internal presents columnar grains. The crystalline phases of the powder are austenite, ferrite, martensite, and carbide, and the carbide includes MC carbide with face-centred structure and M2C carbide with hexagonal structure. The average nano-hardness of the powder is 9.93 GPa, resulting in poor formability, and it can be pressed and formed only after adding binder.

ABSTRACTmiRNAs are increasingly being implicated as key regulators of cell proliferation, apoptosis, and differentiation. miRNA-34c appears to play a crucial role in cancer pathogenesis wherein it exerts its effect as a tumor suppressor. However, the role of miR-34c in myoblast proliferation remains poorly understood. Here, we found that overexpression miR-34c inhibited myoblasts proliferation by reducing the protein and mRNA expression of cell cycle genes. In contrast, blocking the function of miR-34c promoted myoblasts proliferation and increased the protein and mRNA expression of cell cycle genes. Moreover, miR-34c directly targeted YY1 and inhibited its expression. Similar to overexpression miR-34c, knockdown of YY1 by siRNA suppressed myoblasts proliferation. Our study provides novel evidence for a role of miR-34c in inhibiting myoblasts proliferation by repressing YY1. Thus, miR-34c has the potential to be used to enhance skeletal muscle development and regeneration.

A phased array radar seeker (PARS) must be able to effectively decouple body motion and accurately extract the line-of-sight (LOS) rate for target missile tracking. In this study, the real-time two-channel beam pointing error (BPE) compensation method of PARS for LOS rate extraction is designed. The PARS discrete beam motion principium is analyzed, and the mathematical model of beam scanning control is finished. According to the principle of the antenna element shift phase, both the antenna element shift phase law and the causes of beam-pointing error under phantom-bit conditions are analyzed, and the effect of BPE caused by phantom-bit technology (PBT) on the extraction accuracy of the LOS rate is examined. A compensation method is given, which includes coordinate transforms, beam angle margin compensation, and detector dislocation angle calculation. When the method is used, the beam angle margin in the pitch and yaw directions is calculated to reduce the effect of the missile body disturbance and to improve LOS rate extraction precision by compensating for the detector dislocation angle. The simulation results validate the proposed method.

A pervasive challenge in drug design is determining how to expand a ligand─a small molecule that binds to a target biomolecule─in order to improve various properties of the ligand. Adding single chemical groups, known as fragments, is important for lead optimization tasks, and adding multiple fragments is critical for fragment-based drug design. We have developed a comprehensive framework that uses machine learning and three-dimensional protein–ligand structures to address this challenge. Our method, FRAME, iteratively determines where on a ligand to add fragments, selects fragments to add, and predicts the geometry of the added fragments. On a comprehensive benchmark, FRAME consistently improves predicted affinity and selectivity relative to the initial ligand, while generating molecules with more drug-like chemical properties than docking-based methods currently in widespread use. FRAME learns to accurately describe molecular interactions despite being given no prior information on such interactions. The resulting framework for quality molecular hypothesis generation can be easily incorporated into the workflows of medicinal chemists for diverse tasks, including lead optimization, fragment-based drug discovery, and de novodrug design.

This study investigates symptom relief in patients whose hemifacial spasms (HFS) were completely relieved following microvascular decompression (MVD). Patients with HFS who were operated on from January 2007 to May 2011, at our department, were studied. The medical records and operation videos of each patient were reviewed. Follow-up was performed via telephone communication. A total of 410 patients with HFS were divided into two groups: Group A (277 cases): HFS caused by small vascular compression, and Group B (133 cases): HFS caused by vertebral artery compression. Magnetic resonance imaging (MRI) was performed on all the patients to rule out those with secondary HFS. Patients who had undergone previous MVD were also excluded at that time. In all, 462 patients underwent MVD for HFS in our center during the study period. Follow-up was available for 410 patients. In the small vascular compression cohort, 72 (72/277, 26.0 %) HFS patients achieved relief with delayed healing. While in the vertebral artery compression cohort, 52 (52/133, 39.1 %) HFS patients experienced relief with delayed healing. There was significant difference between these two cohorts (P< 0.05). 93.75% of delayed healing patients were cured and experienced spasm relief within 6 months. Surgeons should be aware that delayed symptom relief after MVD for HFS is more common than has been reported, and time course of symptom relief is various as well as unpredictable; however, most HFS patients are cured, and experience spasm relief within 6 months.

Slight deformation of head influences the aerodynamic characteristics of head, after-body, and tail fins of spinning vehicle. The influence of head deformation was analyzed by the DES method. The results reveal that the frequency of interference on the after-body and fins caused by head deformation is different with the spin frequency of vehicle. It is more important that the interference caused by the head deformation has a lag phenomenon, which is related to the flow velocity and the spin rate of the vehicle. The normal force coefficient and side force coefficient of spinning vehicle with deformed head rise as the rotational speed of vehicle increases, and lag behind that in low spin rate conditions. In high Mach number conditions, the fluctuation magnitude of aerodynamic characteristics of spinning vehicle with deformed head is larger than those in low Mach number conditions.

The high demand on direct current (DC) power source generated through triboelectric effect drives the research on semiconductor-based triboelectric nanogenerators (TENGs), which have lower internal resistance. With high flexibility, organic semiconductor-based DC TENGs are more intriguing. In this work, we use organic semiconductor Poly (3,4-ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) as a friction layer to make organic semiconductor-based TENGs. By experimentally analyzing the work functions of PEDOT: PSS, Al alloy, Si, ITO, Cu, and graphene, the DC devices with PEDOT: PSS/Al alloy triboelectric layers exhibit impressive performance. Our PEDOT: PSS/Al alloy DC TENGs achieves open-circuit voltage about 1V, and short-circuit current up to 309 μA. The internal resistance of the DC TENG is tested to be about 2◊104Ω, and the power density reaches 11.67mW/m2. Effects of the load pressure, sliding speed, and size of the devices are systematically studied in this work. The charging probability of our DC TENGs as power sources and human body motion detecting capability as force sensors are all experimentally tested, indicating further potential applications of our PEDOT: PSS/Al alloy DC TENGs as flexible energy sources and motion detector.

In this paper, high‐photosensitive CdS1–xSexfilms are synthesized by a two‐step technique, which includes the chemical bath deposition of CdS films and a following selenization process. The structural, optical, and photoelectric properties of the CdS1–xSexfilms were investigated. With the substitution of selenium for sulfur atoms, grain sizes of the as‐prepared CdS1–xSexfilms are effectively enlarged and reach the scales of the films thickness when the selenization temperature exceeds 450 °C. With increasing the selenization temperature from 350 to 550 °C, the band gaps of CdS1–xSexfilms gradually decrease from 2.37 to 1.82 eV. Under the co‐action of the grain‐size enlargement and band‐gap decrease, the CdS1–xSexfilms fabricated at 450 °C show very pronounced photosensitivity. Noteworthy, the ratio of photo to dark conductivity of the CdS1–xSexfilm selenized at 450 °C reaches 1.1 × 105, suggesting a promising application potential in the photoelectric devices.

• We propose a new hash structure by combining MD5 and chaotic neural network, adding two different parameter step functions to the original MD5 system to increase the complexity of MD5 for Joux multiple collision attacks. • In the data padding, a new data padding method is designed to resist the length extension attack, Joux multiple collision attacks.by using chaotic sequences for placeholders. • The output of each network is both an intermediate link variable and an input parameter for the subsequent modules, the output result will change dramatically after being computed by multiple chaotic neural network modules. This ensures the sensitivity of the hash function, which in turn improves the stability of the system. In this paper, we propose a new chaotic neural network called the Merkle–Damgaard (CNN-MD) iterative structure, which we designed from the perspective of resisting attacks, such as length extension, second original image, Joux multiple collision, and intermediate encounter attacks. A new chaotic hash function based on the CNN-MD is presented. First, CNN is used as the compression function of CNN-MD, which ensures both the unidirectionality of data compression and the sensitivity of the hash value. Furthermore, the multi-input single-output construction of the CNN can achieve highly efficient data compression. In addition, in the process of group encryption of data, we use the value padding of coupled lattice mapping to improve the alignment of the plaintext of the MD algorithm. This new alignment can enhance the hash function's collision resistance and the CNN-MD sensitivity. Experimental and theoretical analyses show that our proposed hashing algorithm can resist attacks, such as second original image, brute force, and multiple collision attacks, better than MD5, SHA-1, and SHA-2 algorithms. In terms of speed, our proposed hashing algorithm can successfully handle existing commercial scenarios better than MD5, SHA-1, SHA-3, and other methods. Therefore, the hash algorithm proposed in this study can be applied to existing e-commerce scenarios. [ABSTRACT FROM AUTHOR]