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Surface-enhanced Raman scattering (SERS) spectroscopy faces challenges in achieving both high sensitivity and reproducibility for the detection of real samples, particularly in high-salinity matrices. In this study, we developed a high-performance, salt-resistant three-dimensional (3D) SERS substrate by integrating physically induced colloidal silver nanoparticle aggregates (AgNAs) with an agarose hydrogel. AgNAs were prepared using a freeze–thaw–ultrasonication method to minimize interference in SERS signals while significantly enhancing the detection efficiency of trace pollutants. The incorporation of the agarose hydrogel not only improved the substrate’s pollutant enrichment capability, but also effectively prevented the aggregation and sedimentation of AgNAs in salt solutions. The developed SERS substrate exhibited an ultralow detection limit of 10−12 M for Nile Blue (NB), with a 100-fold increase in sensitivity compared to colloidal AgNAs and drop-cast AgNAs solid substrates. The analytical enhancement factor (AEF) for malachite green (MG) achieved a value of 1.4 × 107. Furthermore, the substrate demonstrated excellent signal uniformity, with a relative standard deviation (RSD) of 6.74% within a 200 μm × 200 μm detection area and also show a satisfactory RSD of only 9.38% within a larger area of 1 mm × 1 mm. Notably, the 3D SERS substrate exhibited excellent stability under high-salinity conditions (0.5 M NaCl) and successfully detected a model pollutant (MG) in real seawater samples using the standard addition method. This study provides a novel strategy for highly sensitive SERS detection of trace pollutants in saline environments, offering promising applications in environmental monitoring and marine pollution analysis.

Microtextured cutting tools are widely used because of their excellent performance in cutting difficult-to-machine materials. The cutting performance of cutting tools largely depends on the size parameters of the microtextures used. This study focuses on the machining of titanium alloy Ti-6Al4 V using microgrooved cutting tools under dry-cutting conditions. Special emphasis is placed on exploring cutting performance under specific combinations of microgroove parameters. To determine the optimal parameter combination for cutting, the effects of different microgroove parameters (including the diameter, depth, spacing, and spacing between grooves and cutting edges) on cutting force, tool wear, and chip morphology were investigated. In this study, femtosecond laser technology was used to prepare microgroove-textured cutting tools with different parameters, and the cutting performance of these tools was analyzed. The results show that, when the groove diameter is 80 μm, the depth is 60 μm, the spacing is 80 μm, and the distance between the groove and the tool tip is 120 μm, the cutting performance of the tool is optimal: the cutting force is reduced by 13.9%, the degree of tool wear is minimized, and the degree of chip curling is more uniform. The research results can be applied to the actual processing of Ti-6Al4 V, which can help tool design, selection, and microtexture parameter optimization.

Fluorescence analysis is a fast and sensitive method, and has great potential application in trace detection of environmental toxins. However, many important environmental toxins are non-fluorescent substances, and it is still a challenge to construct a fluorescence detection method for non-fluorescent substances. Here, by means of charge transfer effect and smart molecular imprinting technology, we report a sensitive indirect fluorescent sensing mechanism (IFSM) and microcystin (MC-RR) is selected as a model target. A molecular imprinted thin film is immobilized on the surface of zinc ferrite nanoparticles (ZnFe 2 O 4 NPs) by using arginine, a dummy fragment of MC-RR. By implementation of IFSM on the paper-based microfluidic chip, a versatile platform for the quantitative assay of MC-RR is developed at trace level (the limit of detection of 0.43 μg/L and time of 20 min) in real water samples without any pretreatment. Importantly, the proposed IFSM can be easily modified and extended for the wide variety of species which lack direct interaction with the fluorescent substrate. This work offers the potential possibility to meet the requirements for the on-site analysis and may explore potential applications of molecularly imprinted fluorescent sensors. Fluorescence analysis is a fast and sensitive method for the trace detection of environmental toxins, but it remains challenging to develop a fluorescence method for detecting nonfluorescent toxins. Here, the authors report an indirect fluorescent sensing strategy for the rapid, selective and sensitive detection of the non-fluorescent microcystin as a model target.

Homoploid hybrid speciation (HHS) has been increasingly recognized as occurring widely during species diversification of both plants and animals. However, previous studies on HHS have mostly focused on closely-related species while it has been rarely reported or tested between ancestors of different genera. Here, we explore the likely HHS origin of Carpinus sect. Distegocarpus between sect. Carpinus and Ostrya in the family Betulaceae. We generate a chromosome-level reference genome for C. viminea of sect. Carpinus and re-sequence genomes of 44 individuals from the genera Carpinus and Ostrya . Our integrated analyses of all genomic data suggest that sect. Distegocarpus , which has three species, likely originates through HHS during the early divergence between Carpinus and Ostrya . Our study highlights the likelihood of an HHS event between ancestors of the extant genera during their initial divergences, which may have led to reticulate phylogenies at higher taxonomic levels. Carpinus fangiana exhibits intermediate morphology between C. viminea and Ostrya rehderiana . Here, the authors report that Carpinus sect. Distegocarpus likely originate through homoploid hybrid speciation (HHS) during the early divergence between Carpinus and Ostrya through genomic analyses.

Colloidal noble metal nanoparticle aggregates have demonstrated significant advantages in surface-enhanced Raman scattering (SERS) analysis, particularly for online detection, due to their excellent optical properties, spatial homogeneity, and fluidic compatibility. However, conventional chemically induced aggregation methods (such as salt-induced nanoparticle aggregation) suffer from uncontrolled aggregation, limited stability, and narrow detection windows, which restrict their quantitative and long-term applications. In this study, we developed a non-chemical method for fabricating stable colloidal aggregates from uniform β-cyclodextrin-stabilized silver nanoparticles (β-CD@AgNPs) via centrifugation. By precisely controlling the addition rate of silver nitrate, we synthesized β-cyclodextrin-stabilized silver nanoparticles with a uniform size. Surprisingly, these nanoparticles can form highly dispersed and homogeneous colloidal aggregates simply via centrifugation, which is completely different from the behavior of traditional ligand-modified nanoparticles. Notably, the resulting aggregates exhibit excellent SERS enhancement, enabling the sensitive detection of various dyes at nanomolar levels. Furthermore, they maintain a stable SERS signal (RSD = 6.99%) over a detection window exceeding 1 h, markedly improving signal stability and reproducibility compared with salt-induced aggregates. Additionally, using pyocyanin as a model analyte, we evaluated the quantitative performance of these aggregates (LOD = 0.2 nM), achieving satisfactory recovery (82–117%) in spiked samples of drinking water, lake water, and tap water. This study provides a facile strategy for fabricating stable colloidal SERS substrates and paves the way for the advancement of SERS applications in analytical sciences.

Early-onset sepsis (EOS) remains a leading cause of mortality and neurodevelopmental injury in preterm infants, yet widely used tools (e.g., Kaiser EOS Calculator) are not designed for <35-37 weeks' gestation. To develop and internally validate a concise, clinically interpretable nomogram for EOS risk stratification in preterm neonates and to evaluate its potential for antibiotic stewardship. We performed a single-center retrospective cohort study (July 2023-June 2024) including 1,059 preterm infants admitted within 72 h of birth, randomly split 7:3 into training (n = 742) and validation (n = 317). Forty-five maternal and neonatal candidates were screened (univariable tests, LASSO), followed by multivariable logistic regression to build the final model and nomogram. Discrimination (AUC), calibration (Brier score, calibration curve, Hosmer-Lemeshow), and decision-curve analysis (DCA) were assessed; two biologically plausible interactions were prespecified. Four routinely available variables-gestational age, birth weight, umbilical cord abnormality, and mechanical ventilation within 72 h-composed the final model. In the validation cohort, AUC was 0.818 (95% CI, 0.767-0.868), Brier score 0.158, and Hosmer-Lemeshow P = 0.71; DCA showed net benefit across 5-65% risk thresholds. Using a ≥ 0.70 treatment threshold, the model identified 88% of EOS cases while recommending antibiotics for ~10% of infants. A culture-proven-only sensitivity analysis yielded comparable discrimination (AUC 0.819) with a Brier score 0.041. A four-factor nomogram using EMR-available variables accurately stratifies EOS risk in preterm infants and may support risk-based antibiotic decisions while limiting overtreatment. Prospective multicenter external validation is warranted to confirm generalizability and guide implementation.

Surface-enhanced Raman spectroscopy (SERS) is widely employed due to its high sensitivity and distinctive fingerprinting capabilities. Colloidal nanoaggregates are commonly used as SERS substrates because of their mobility and the abundance of “hotspots”. Although the reagent-free “freeze-thaw-ultrasonication” method for preparing Ag nanoaggregates (AgNAs) does not introduce additional background interference and maintains the original interfacial properties of AgNAs, their unstable physical nanostructure limits SERS detection to just 7 days. Herein, we demonstrate mesoporous silica-encapsulated colloidal Ag nanoaggregates (AgNAs@m-SiO2) by combining a freeze-thaw-ultrasonication method and a cetyltrimethylammonium bromide (CTAB)-assisted silanization reaction, achieving long-term SERS stability of more than two months. The prepared AgNAs@m-SiO2 serve a dual capability: (1) preserving electromagnetic “hotspots” for ultra-sensitive detection (e.g., malachite green detection limit: 3.60 × 10−8 M), and (2) maintaining structural stability under harsh conditions. The AgNAs@m-SiO2 substrate exhibited superior structural stability after 50 min of ultrasonic treatment, with an initial SERS signal retention of 91.8%, which is twice that of the bare AgNAs (retention of 45%). The long-term performance further highlighted its superiority: after 70 days of storage, the composite maintained 84.3% of its original signal strength, outperforming the uncoated controls by over ten times (which retained only 8%). Crucially, the substrate’s robust design enables the direct detection of contaminants in real environmental matrices (river and seawater) for qualitative analyses and water quality assessments, thus validating its suitability for environmental sensing applications in the field.

Based on the analysis of the current situation of roof snow removal technology at home and abroad, this paper proposes a fully automatic roof snow removal device based on visual sensing technology. This product is composed of five functional modules: cutting snow removal module, frozen snow assisting removal module, pulley block anti-drop module, worm gear transmission module, and crawler movement module. Through the cooperation of various mechanisms, the efficient removal of snow on the roof is realized. Automatic removal can effectively reduce the adverse impact of snow on the roof on residents’ lives and economic development.

A convergent approach for the enantioselective construction of an advanced intermediate containing the [5,5,6,6]-tetracyclic core framework of the khayanolide-type limonoids was described. The strategy features an acylative kinetic resolution of the benzylic alcohol, a 1,2-Grignard addition and an AcOH-interrupted Nazarov cyclization.

Dioecy, the presence of separate sexes on distinct individuals, has evolved repeatedly in multiple plant lineages. However, the specific mechanisms by which sex systems evolve and their commonalities among plant species remain poorly understood. With both XY and ZW sex systems, the family Salicaceae provides a system to uncover the evolutionary forces driving sex chromosome turnovers. In this study, we performed a genome-wide association study to characterize sex determination in two Populus species, P. euphratica and P. alba. Our results reveal an XY system of sex determination on chromosome 14 of P. euphratica, and a ZW system on chromosome 19 of P. alba. We further assembled the corresponding sex-determination regions, and found that their sex chromosome turnovers may be driven by the repeated translocations of a Helitron-like transposon. During the translocation, this factor may have captured partial or intact sequences that are orthologous to a type-A cytokinin response regulator gene. Based on results from this and other recently published studies, we hypothesize that this gene may act as a master regulator of sex determination for the entire family. We propose a general model to explain how the XY and ZW sex systems in this family can be determined by the same RR gene. Our study provides new insights into the diversification of incipient sex chromosomes in flowering plants by showing how transposition and rearrangement of a single gene can control sex in both XY and ZW systems.