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Air-core photonic bandgap fiber (PBF) is the perfect choice of the next-generation fiber optical gyroscope (FOG), with excellent temperature, electromagnetism and radiation adaptability. Numerical aperture is an important optical parameter of PBF for application in FOG. The PBF’s maximum theoretical numerical aperture (NAmax) is calculated and compared with the far-field numerical aperture (NAeff) through experiments. The result indicates that the relationship between NAmax and NAeff has much stronger dependence on wavelength than that of the conventional fiber, and they get close at wavelengths near the middle of the photonic bandgap with the error less than 5%. Furthermore, photonic bandgap fiber optical gyroscope (PBFOG) with no fusion splicing points is proposed, and the optimization method and results of the PBF’s structure parameters for application in PBFOG are given from the aspect of numerical aperture.

Reducing interface nonradiative recombination is important for realizing highly efficient perovskite solar cells. In this work, we develop a synergistic bimolecular interlayer (SBI) strategy via 4-methoxyphenylphosphonic acid (MPA) and 2-phenylethylammonium iodide (PEAI) to functionalize the perovskite interface. MPA induces an in-situ chemical reaction at the perovskite surface via forming strong P-O-Pb covalent bonds that diminish the surface defect density and upshift the surface Fermi level. PEAI further creates an additional negative surface dipole so that a more n-type perovskite surface is constructed, which enhances electron extraction at the top interface. With this cooperative surface treatment, we greatly minimize interface nonradiative recombination through both enhanced defect passivation and improved energetics. The resulting p-i-n device achieves a stabilized power conversion efficiency of 25.53% and one of the smallest nonradiative recombination induced V oc loss of only 59 mV reported to date. We also obtain a certified efficiency of 25.05%. This work sheds light on the synergistic interface engineering for further improvement of perovskite solar cells. Reducing interface nonradiative recombination is important for realizing highly efficient perovskite solar cells. Here, the authors employ a bimolecular interlayer to functionalize the perovskite interface, achieving cooperative surface treatment and certified power conversion efficiency of 25.05%.

Image segmentation, which has become a research hotspot in the field of image processing and computer vision, refers to the process of dividing an image into meaningful and non-overlapping regions, and it is an essential step in natural scene understanding. Despite decades of effort and many achievements, there are still challenges in feature extraction and model design. In this paper, we review the advancement in image segmentation methods systematically. According to the segmentation principles and image data characteristics, three important stages of image segmentation are mainly reviewed, which are classic segmentation, collaborative segmentation, and semantic segmentation based on deep learning. We elaborate on the main algorithms and key techniques in each stage, compare, and summarize the advantages and defects of different segmentation models, and discuss their applicability. Finally, we analyze the main challenges and development trends of image segmentation techniques.

Solar-driven H 2 O 2 production provides an eco-friendly and scalable alternative to conventional anthraquinone processes. However, its efficiency has been limited by the inefficient charge separation and poor selectivity for the two-electron oxygen reduction reaction (2e - ORR). Here we report a Z-scheme heterojunction photocatalyst constructed by in-situ growth of sulfur-deficient ZnIn 2 S 4 nanosheets onto UiO-66-NH 2 (a zirconium-based metal-organic framework). This heterojunction promotes efficient charge separation while retaining strong redox capability, and sulfur vacancies regulate O 2 adsorption into a configuration that suppresses O-O bond cleavage and favors 2e - ORR. As a result, the composite achieves a high H 2 O 2 production rate of 3200 μmol g -1 h -1 with 94.3% selectivity in pure water under ambient air and visible light. A continuous-flow prototype exhibits stable performance for over 200 h, and the generated H 2 O 2 solution enables direct bacteria disinfection. Spectroscopic and theoretical analyses reveal the critical role of sulfur vacancies in optimizing O 2 activation. Our findings highlight a synergistic strategy of tuning charge dynamics and O 2 adsorption configurations for designing next-generation systems for sustainable H 2 O 2 production and water disinfection. H 2 O 2 photosynthesis offers a green alternative to traditional methods, but challenges remain in charge separation and reaction selectivity. Here, the authors report Z-scheme photocatalysts where sulfur vacancy regulates O 2 adsorption configuration, enhancing H 2 O 2 production with high selectivity.

Traditional electrical resistivity tomography (ERT) technology confronts bottlenecks such as the volume effect in the detection of termite nests in levees, while the ERT based on deep learning has insufficient interpretation accuracy due to small sample data. This study proposes an intelligent ERT diagnosis framework that integrates generative adversarial networks (GANs) with semantic segmentation models. The GAN-enhanced networks (GFU-Net and GFL-Net) are developed, incorporating a Squeeze-and-Excitation (SE) attention mechanism to suppress false anomalies. Additionally, a comprehensive loss function combining binary cross-entropy (BCE) and the Focal loss function is used to address the issue of sample imbalance. Using forward modeling based on the finite difference method (FDM), a termite nest hidden danger ERT dataset, which includes seven types of high-resistance anomaly configurations, is generated. Numerical simulations demonstrate that GFL-Net achieves a mean intersection-over-union (mIoU) of 97.68% and a spatial positioning error of less than 0.04 m. In field validation on a red clay embankment in Jiangxi Province, this method significantly improves the positioning accuracy of hidden termite nests compared to traditional least squares (LS) inversion. Excavation verification results show that the maximum error in the horizontal center and top burial depth of the termite nest identified by GFL-Net is less than 7% and 16%, respectively. The research findings provide reliable technical support for the accurate identification of termite nest hidden dangers in embankments.

BackgroundOxidative stress is currently one of the main threats to animal health, and flavonoids in forage have good antioxidant activity. However, the impact of fermentation on flavonoids and their antioxidant activity in forage is still unclear. This study aims to investigate the effect of lactic acid bacteria inoculation on the biological transformation of flavonoids in alfalfa silage fermentation and its relationship with antioxidant activity.ResultsCompared with the raw materials, silage fermentation can increase the total flavonoid content of alfalfa. The addition of Pediococcus pentosaceus (CP115739.1) and Lactiplantibacillus plantarum (CP115741.1) can significantly increase the total flavonoid content in alfalfa silage (P < 0.05). The addition of lactic acid bacteria significantly improved the antioxidant capacity of alfalfa silage (P < 0.05). Pearson correlation analysis showed a significant correlation between total flavonoids and DPPH (R = 0.62, P < 0.05), and a highly significant correlation between total flavonoids and FRAP (R = 0.70, P < 0.01). Compared with natural silage fermentation, the addition of lactic acid bacteria leads to changes in the biological transformation process of flavonoids in alfalfa. Its unique products, 3,7,4′-trioxyflavonoids, as well as acacetin and taxifolin 7-O-rhamnoside, are significantly positively correlated with antioxidant activity.ConclusionsSilage fermentation contributes to the transformation of flavonoids, and inoculation with certain lactic acid bacteria can increase the content of flavonoids (including apigenin, luteolin, and other free flavonoids). It is worth noting that after fermentation, the antioxidant capacity of alfalfa is significantly improved, which may be attributed to the biotransformation of flavonoids related to acacetin, 3,7,4′-trihydroxyflavonoids, and taxifolin 7-O-rhamnoside. This study provides a potential pathway for obtaining value-added silage fermentation products by selecting specific lactic acid bacteria inoculants.

In this paper, a full-cycle interactive progressive (FIP) method that integrates topology optimization, parametric optimization, and experimental analysis to determine the optimal energy absorption properties in the design of chiral mechanical metamaterials is proposed. The FIP method has improved ability and efficiency compared with traditional design methods due to strengthening the overall design, introducing surrogate models, and its consideration of the application conditions. Here, the FIP design was applied in the design of mechanical metamaterials with optimized energy absorption properties, and a chiral mechanical metamaterial with good energy absorption and impact resistance was obtained based on the rotation mechanism of metamaterials with a negative Poisson’s ratio. The relationship among the size parameters, applied boundary conditions, and energy absorption properties were studied. An impact compression experiment using a self-made Fiber Bragg Grating sensor was carried out on the chiral mechanical metamaterial. In light of the large deviation of the experimental and simulation data, a feedback adjustment was carried out by adjusting the structural parameters to further improve the mechanical properties of the chiral mechanical metamaterial. Finally, human–computer interaction, self-innovation, and a breakthrough in the design limits of the optimized model were achieved. The results illustrate the effectiveness of the FIP design method in improving the energy absorption properties in the design of chiral mechanical metamaterials.

The naturally attached phyllosphere microbiota play a crucial role in plant-derived fermentation, but the structure and function of phyllosphere endophytes remain largely unidentified. Here, we reveal the diversity, specificity, and functionality of phyllosphere endophytes in alfalfa ( Medicago sativa L.) through combining typical microbial culture, high-throughput sequencing, and genomic comparative analysis. In comparison to phyllosphere bacteria (PB), the fermentation of alfalfa solely with endophytes (EN) enhances the fermentation characteristics, primarily due to the dominance of specific lactic acid bacteria (LAB) such as Lactiplantibacillus , Weissella , and Pediococcus . The inoculant with selected endophytic LAB strains also enhances the fermentation quality compared to epiphytic LAB treatment. Especially, one key endophytic LAB named Pediococcus pentosaceus EN5 shows enrichment of genes related to the mannose phosphotransferase system (Man-PTS) and carbohydrate-metabolizing enzymes and higher utilization of carbohydrates. Representing phyllosphere, endophytic LAB shows great potential of promoting ensiling and provides a novel direction for developing microbial inoculant. The study reveals the diversity, specificity and functionality of phyllosphere endophytes in alfalfa silage fermentation and finds a unique microbe resource in phyllosphere endophytes which tends to enrich genes related to carbohydrate utilization.

Background Minimally invasive surgery for perihilar cholangiocarcinoma (pCCA) is in an exploratory phase by now and is only recommended for carefully selected patients. Patients and Methods Our team performed total laparoscopic hepatectomy in a 64-year-old woman with perihilar cholangiocarcinoma type IIIb. Laparoscopic left hepatectomy and caudate lobectomy were performed involving a no-touch en-block technique. Meanwhile, extrahepatic bile duct resection, radical lymphadenectomy with skeletonization, and biliary reconstruction were performed. Results Laparoscopic left hepatectomy and caudate lobectomy were successfully performed in 320 min with 100 ml of blood loss. The histological grading was T2bN0M0 (stage II). The patient was discharged on the 5th day without postoperative complications. Following the operation, the patient received single-drug capecitabine chemotherapy. There was no recurrence after 16 months of follow-up. Conclusion Our experience is that, in selected patients with pCCA type IIIb or type IIIa, laparoscopic resection can reach comparable outcome to open surgery with standardized lymph node dissection by skeletonization, use of no-touch en-block technique, and proper digestive tract reconstruction.