Passive Eavesdropping Can Significantly Slow Down RIS-Assisted Secret Key Generation

Reconfigurable Intelligent Surface (RIS) assisted physical layer key generation has shown great potential to secure wireless communications by smartly controlling signals such as phase and amplitude. However, previous studies mainly focus on RIS adjustment under ideal conditions, while the correlation between the eavesdropping channel and the legitimate channel, a more practical setting in the real world, is still largely under-explored for the key generation. To fill this gap, this paper aims to maximize the RIS-assisted physical-layer secret key generation by optimizing the RIS units switching under the eavesdropping channel. Firstly, we theoretically show that passive eavesdropping significantly reduces RIS-assisted secret key generation. Keeping this in mind, we then introduce a mathematical formulation to maximize the key generation rate and provide a step-by-step analysis. Extensive experiments show the effectiveness of our method in benefiting the secret key capacity under the eavesdropping channel. We also observe that the key randomness, and unmatched key rate, two metrics that measure the secret key quality, are also significantly improved, potentially paving the way to RIS-assisted key generation in real-world scenarios.Comment: Accepted by Globecom 202

Formation and properties of chalcogenide glasses based on GeS2-​Sb2S3-​AgI system

International audienceNovel glasses in GeS2-​Sb2S3-​AgI system have been prepd. by melt-​quenching method. A large glass-​forming region was found in this novel system, in which almost 60 mol​% AgI has been incorporated. The basic physiochem. properties of glass samples were investigated. With the addn. of AgI, red shift of short-​wavelength absorption edge and distinct drop of the glass transition temp. (Tg) were obsd. In addn., a high Ag+ ion cond. of 6.37×10-​4 S​/cm at room temp. was obtained in 55(0.6GeS2-​0.4Sb2S3)​-​45AgI sample, indicating that these glasses have potential application as amorphous solid electrolytes

Comparative transcriptome analysis of genes involved in paradormant bud release response in ‘Summer Black’ grape

Grapevines possess a hierarchy of buds, and the fruitful winter bud forms the foundation of the two-crop-a-year cultivation system, yielding biannual harvests. Throughout its developmental stages, the winter bud sequentially undergoes paradormancy, endodormancy, and ecodormancy to ensure survival in challenging environmental conditions. Releasing the endodormancy of winter bud results in the first crop yield, while breaking the paradormancy of winter bud allows for the second crop harvest. Hydrogen cyanamide serves as an agent to break endodormancy, which counteracting the inhibitory effects of ABA, while H2O2 and ethylene function as signaling molecules in the process of endodormancy release. In the context of breaking paradormancy, common agronomic practices include short pruning and hydrogen cyanamide treatment. However, the mechanism of hydrogen cyanamide contributes to this process remains unknown. This study confirms that hydrogen cyanamide treatment significantly improved both the speed and uniformity of bud sprouting, while short pruning proved to be an effective method for releasing paradormancy until August. This observation highlights the role of apical dominance as a primary inhibitory factor in suppressing the sprouting of paradormant winter bud. Comparative transcriptome analysis revealed that the sixth node winter bud convert to apical tissue following short pruning and established a polar auxin transport canal through the upregulated expression of VvPIN3 and VvTIR1. Moreover, short pruning induced the generation of reactive oxygen species, and wounding, ethylene, and H2O2 collectively acted as stimulating signals and amplified effects through the MAPK cascade. In contrast, hydrogen cyanamide treatment directly disrupted mitochondrial function, resulting in ROS production and an extended efficacy of the growth hormone signaling pathway induction

Investigation of the chemical residuals on the fused silica during chemical mechanical polishing

Chemical residuals on fused silica after chemical mechanical polishing with silica and ceria have been analyzed. The surface of fused silica terminates with silanol after being polished with silica abrasives but ends up with Ce‐O−Si in a ceria‐based slurry under the CMP environment. The silanol firstly synthesizes on a fused silica surface polished with ceria, but then further reacts with hydroxyl cerium groups scattering in the slurry forming Ce‐O−Si. It also reveals that polishing fused silica with silica abrasives is an alternative way giving an ultra smooth surface

Metformin ameliorates ionizing irradiation-induced long-term hematopoietic stem cell injury in mice

AbstractExposure to ionizing radiation (IR) increases the production of reactive oxygen species (ROS) not only by the radiolysis of water but also through IR-induced perturbation of the cellular metabolism and disturbance of the balance of reduction/oxidation reactions. Our recent studies showed that the increased production of intracellular ROS induced by IR contributes to IR-induced late effects, particularly in the hematopoietic system, because inhibition of ROS production with an antioxidant after IR exposure can mitigate IR-induced long-term bone marrow (BM) injury. Metformin is a widely used drug for the treatment of type 2 diabetes. Metformin also has the ability to regulate cellular metabolism and ROS production by activating AMP-activated protein kinase. Therefore, we examined whether metformin can ameliorate IR-induced long-term BM injury in a total-body irradiation (TBI) mouse model. Our results showed that the administration of metformin significantly attenuated TBI-induced increases in ROS production and DNA damage and upregulation of NADPH oxidase 4 expression in BM hematopoietic stem cells (HSCs). These changes were associated with a significant increase in BM HSC frequency, a considerable improvement in in vitro and in vivo HSC function, and complete inhibition of upregulation of p16Ink4a in HSCs after TBI. These findings demonstrate that metformin can attenuate TBI-induced long-term BM injury at least in part by inhibiting the induction of chronic oxidative stress in HSCs and HSC senescence. Therefore, metformin has the potential to be used as a novel radioprotectant to ameliorate TBI-induced long-term BM injury

The Immungenicity and Cross-Neutralizing Activity of Enterovirus 71 Vaccine Candidate Strains

This study aimed to evaluate enterovirus 71 (EV-A71) vaccine candidate strains, including their genotypes, immunogenicity and cross-neutralization capacity. From clinical samples, EV-A71 strains were separated by using Vero cells. Six strains were chosen for vaccine candidates, and the sequences were analyzed. To detect the immunogenicity of the strains, we used them to immunize NIH mice at 0 and 14 days. Cytopathic effects (CPE) were examined to determine the EV-A71 neutralizing antibody (NTAb) titer 14 d after the first and second inoculations. To evaluate the cross-neutralizing capacity of the EV-A71 vaccine candidate strains, we tested serum immunized mice with ten EV-A71 genotype strains. Six EV-A71 vaccine candidate strains were identified, all belonging to sub-genotype C4, the prevalent genotype in China. The sequence similarity of the VP1 regions of the six candidate vaccine strains and three approved inactivated vaccines was 97.58%–97.77%, and the VP1 amino acid similarity was 98.65%–99.33%. Experiments were performed to evaluate the immunogenicity and cross-neutralizing activity of the EV-A71 vaccine candidate strains. The strains had good immunogenicity 14 d after two immunizations, inducing an NTAb titer ranging from 1:94 to 1:346. The NTAb seroconversion rates 14 d after one immunization were above 80% (except HB0007), and significantly increased immunogenicity of EV-A71 strains was observed post-inoculation. Furthermore, our candidate vaccine strains had broad cross-neutralizing activity after challenge with ten sub-genotypes of EV-A71. The highest NTAb titer/lowest NTAb titer ratios of sera against EV-A71 sub-genotypes were 8.0 (JS0002), 8.0 (JS0005), 21.3 (HB0005), 21.3 (HB0007), 10.7 (HB0040) and 8.0 (GD0002), respectively. Our EV-A71 strains had good immunogenicity and cross-neutralization activity, and have the potential to serve as vaccine strains for multivalent hand, foot and mouth disease vaccines

Atomically smooth gallium nitride surfaces generated by chemical mechanical polishing with non-noble metal catalyst(Fe-Nx/C) in acid solution

In this paper, a novel method for preparing atomically smooth gallium nitride (GaN) wafer surfaces which involves chemical mechanical polishing with a non-noble metal catalyst (Fe-N x ) in acidic slurry is presented. It was confirmed that non-noble metal catalyst based slurry could be used for gallium face of GaN. Atomic force microscope images of the processed surface indicate that an atomically flat surface with Ra=0.0518 nm was achieved after planarization and the processed surface has an atomic step-terrace structure. Besides, the rate of removal of the GaN surface was measured to be approximately 66.9 nm/h, more than triple times higher than that nothing was used as catalyst

CMP of GaN using sulfate radicals generated by metal catalyst

A method for preparing atomically smooth gallium nitride (GaN) surface with high material removal rate that involves chemical mechanical polishing with sulfate radical (SO4 center dot-) oxidizer and Fe2+ activator in slurry is presented. The results indicate that complexing agent with Fe2+ activator is the key point to obtain atomically smooth GaN surface and higher removal rate of GaN. Atomic force microscope (AFM) shows that the average surface roughness (Ra) is 0.0601nm

CMP of GaN using sulfate radicals generated by metal catalyst

A method for preparing atomically smooth gallium nitride (GaN) surface with high material removal rate that involves chemical mechanical polishing with sulfate radical (SO 4 - ) oxidizer and Fe 2+ activator in slurry is presented. The results indicate that complexing agent with Fe 2+ activator is the key point to obtain atomically smooth GaN surface and higher removal rate of GaN. Atomic force microscope (AFM) shows that the average surface roughness (Ra) is 0.0601nm

Fe-Nx/C assisted chemical–mechanical polishing for improving the removal rate of sapphire

In this paper, a novel non-noble metal catalyst (Fe-Nx/C) is used to improve the removal mass of sapphire as well as obtain atomically smooth sapphire wafer surfaces. The results indicate that Fe-Nx/C shows good catalytic activity towards sapphire removal rate. And the material removal rates (MRRs) are found to vary with the catalyst content in the polishing fluid. Especially that when the polishing slurry mixes with 16 ppm Fe-Nx/C shows the maximum MRR and its removal mass of sapphire is 38.43 nm/min, more than 15.44% larger than traditional CMP using the colloidal silicon dioxide (SiO2) without Fe-Nx/C. Catalyst-assisted chemical–mechanical polishing of sapphire is studied with X-ray photoelectron spectroscopy (XPS). It is found that the formation of a soft hydration layer (boehmite, γ-AlOOH or γ-AlO(OH)) on sapphire surface facilitates the material removal and achieving fine surface finish on basal plane. Abrasives (colloid silica together with magnetite, ingredient of Fe-Nx/C) with a hardness between boehmite and sapphire polish the c-plane of sapphire with good surface finish and efficient removal. Fe2O3, Fe3O4, pyridinic N as well as pyrrolic N group would be the catalytical active sites and accelerate this process. Surface quality is characterized with atomic force microscopy (AFM). The optimum CMP removal by Fe-Nx/C also yields a superior surface finish of 0.078 nm the average roughness (Ra)