Combining the Elicitor Up-Regulated Production of Unusual Linear Diterpene-Derived Variants for an In-Depth Assessment of the Application Value and Risk of the Medicinal and Edible Basidiomycete Schizophyllum commune.

To better assess the practical value and avoid potential risks of the traditionally medicinal and edible basidiomycete Schizophyllum commune, which may arise from undescribed metabolites, a combination of elicitors was introduced for the first time to discover products from cryptic and low-expressed gene clusters under laboratory cultivation. Treating S. commune NJFU21 with the combination of five elicitors led to the upregulated production of a class of unusual linear diterpene-derived variants, including eleven new ones (1-11), along with three known ones (12-14). The structures and stereochemistry were determined by 1D and 2D NMR, HRESIMS, ECD, OR and VCD calculations. Notably, the elongation terminus of all the diterpenes was decorated by an unusual butenedioic acid moiety. Compound 1 was a rare monocyclic diterpene, while 2-6 possessed a tetrahydrofuran moiety. The truncated metabolites 4, 5 and 13 belong to the trinorditerpenes. All the diterpenes displayed approximately 70% scavenging of hydroxyl radicals at 50 µM and null cytotoxic activity at 10 µM. In addition, compound 1 exhibited potent antifungal activity against the plant pathogenic fungi Colletotrichum camelliae, with MIC values of 8 µg/mL. Our findings indicated that this class of diterpenes could provide valuable protectants for cosmetic ingredients and the lead compounds for agricultural fungicide development.

A Water-Soluble Thermoplastic Polyamide Acid Sizing Agents for Enhancing Interfacial Properties of Carbon Fibre Reinforced Polyimide Composites.

Carbon-fiber-reinforced polyimide (PI) resin composites have gained significant attention in the field of continuous-fiber-reinforced polymers, in which the interfacial bonding between carbon fiber and matrix resin has been an important research direction. This study designed and prepared a water-soluble thermoplastic polyamide acid sizing agent to improve the wettability of carbon fiber, enhance the van der Waals forces between carbon fiber and resin and strengthen the chemical bonding between the sizing agent and the alkyne-capped polyimide resin by introducing alkyne-containing functional groups into the sizing agent. This study found that the addition of a sizing layer effectively bridged the large modulus difference between the fiber and resin regions, resulting in the formation of an interfacial layer approximately 85 nm thick. This layer facilitated the transfer of stress from the matrix to the reinforced carbon fiber, leading to a significant improvement in the interfacial properties of the composites. Adjusting the concentration of the sizing agent showed that composites treated with 3% had the best interfacial properties. The interfacial shear strength increased from 82.08 MPa to 108.62 MPa (32.33%) compared to unsized carbon fiber. This research is significant for developing sizing agents suitable for carbon-fiber-reinforced polyimide composites.

The Influence of Rhenium Content on Helium Desorption Behavior in Tungsten-Rhenium Alloy.

To investigate the influence of different rhenium contents on the helium desorption behavior in tungsten-rhenium alloys, pure tungsten and tungsten-rhenium alloys were irradiated with helium under the same conditions. All irradiated samples were characterized using TDS and DBS techniques. The results indicate that the addition of rhenium can reduce the total helium desorption quantity in tungsten-rhenium alloys and slightly accelerate the reduction in the concentration of vacancy-type defects accompanying helium dissociation. The desorption activation energy of helium is approximately 2 eV at the low-temperature peak (~785 K) and about 4 eV at the high-temperature peak (~1475 K). An increase in rhenium content causes the desorption peak to shift towards higher temperatures (>1473 K), which is attributed to the formation of the stable complex structures between rhenium and vacancies. Besides, the migration of He-vacancy complexes towards traps and dynamic annealing processes both lead to the recovery of vacancy-type defects, resulting in a decrease in the positron annihilation S parameters.

FF-HPINet: A Flipped Feature and Hierarchical Position Information Extraction Network for Lane Detection.

Effective lane detection technology plays an important role in the current autonomous driving system. Although deep learning models, with their intricate network designs, have proven highly capable of detecting lanes, there persist key areas requiring attention. Firstly, the symmetry inherent in visuals captured by forward-facing automotive cameras is an underexploited resource. Secondly, the vast potential of position information remains untapped, which can undermine detection precision. In response to these challenges, we propose FF-HPINet, a novel approach for lane detection. We introduce the Flipped Feature Extraction module, which models pixel pairwise relationships between the flipped feature and the original feature. This module allows us to capture symmetrical features and obtain high-level semantic feature maps from different receptive fields. Additionally, we design the Hierarchical Position Information Extraction module to meticulously mine the position information of the lanes, vastly improving target identification accuracy. Furthermore, the Deformable Context Extraction module is proposed to distill vital foreground elements and contextual nuances from the surrounding environment, yielding focused and contextually apt feature representations. Our approach achieves excellent performance with the F1 score of 97.00% on the TuSimple dataset and 76.84% on the CULane dataset.

On the evolutionary trail of MagRs.

Magnetic sense, or termed magnetoreception, has evolved in a broad range of taxa within the animal kingdom to facilitate orientation and navigation. MagRs, highly conserved A-type iron-sulfur proteins, are widely distributed across all phyla and play essential roles in both magnetoreception and iron-sulfur cluster biogenesis. However, the evolutionary origins and functional diversification of MagRs from their prokaryotic ancestor remain unclear. In this study, MagR sequences from 131 species, ranging from bacteria to humans, were selected for analysis, with 23 representative sequences covering species from prokaryotes to Mollusca, Arthropoda, Osteichthyes, Reptilia, Aves, and mammals chosen for protein expression and purification. Biochemical studies revealed a gradual increase in total iron content in MagRs during evolution. Three types of MagRs were identified, each with distinct iron and/or iron-sulfur cluster binding capacity and protein stability, indicating continuous expansion of the functional roles of MagRs during speciation and evolution. This evolutionary biochemical study provides valuable insights into how evolution shapes the physical and chemical properties of biological molecules such as MagRs and how these properties influence the evolutionary trajectories of MagRs.

Biocompatible and Biodegradable 3D Graphene/Collagen Fiber Hybrids for High-Performance Conductive Networks and Sensors.

Polymer-based flexible conductive materials are crucial for wearable electronics, electronic skin, and other smart materials. However, their development and commercial applications have been hampered by the lack of strain tolerance in the conductive network, poor bonding with polymers, discomfort during wear, and a lack of biocompatibility. This study utilized oil-tanned leather with a natural network structure, high toughness, and high tensile deformation recovery as a structural template. A graphene (Gr) conductive network was then constructed on the collagen network of the leather, with coordination cross-linking between Gr and collagen fibers through aluminum ions (Al3+). A new flexible conductive material (Al-GL) was then constructed. Molecular dynamics simulations and experimental validation revealed the existence of physical adsorption, hydrogen bonding adsorption, and ligand bonding between Al3+, Gr, and collagen fibers. Although we established that the binding sites between Al3+ and collagen fibers were primarily on carboxyl groups (-COOH), the mechanism of chemical bonding between Gr and collagen fibers remains unclear. The Al-GL composite exhibited a high shrinkage temperature (67.4 °C) and low electrical resistance (16.1 kΩ·sq-1), as well as good softness (9.33 mN), biocompatibility, biodegradability (<60 h), and air and moisture permeability. Furthermore, the incorporation of Al3+ resulted in a heightened Gr binding strength on Al-GL, and the resistance remained comparable following 1 h of water washing. The Al-GL sensor prepared by WPU encapsulation not only demonstrated highly sensitive responses to diverse motion signals of the human body but also retained a certain degree of response to external mechanical effects underwater. Additionally, the Al-GL-based triboelectric nanogenerator (Al-GL TENG) exhibited distinct response signals to different materials. The Al-GL prepared by the one-pot method proposed in this study offers a novel approach to combining functional nanofillers and substrate materials, providing a theoretical foundation for collagen fiber-based flexible conductive materials.

The influence of digestive tract protein on cytotoxicity of polyvinyl chloride microplastics.

Microplastics in food and drinking water can enter the human body through oral exposure, posing potential health risks to the human health. Most studies on the toxic effects of microplastics have focused on aquatic organisms, but the effects of the human digestive environment on the physicochemical properties of microplastics and their potential toxicity during gastrointestinal digestion are often limited. In this study, we first studied the influence of interactions between digestive tract protein (α-amylase, pepsin, and trypsin) and microplastics on the activity and conformation of digestive enzymes, and the physicochemical properties of polyvinyl chloride microplastics (PVC-MPs). Subsequently, a simulated digestion assay was performed to determine the biotransformation of PVC-MPs in the digestive tract and the intestinal toxicity of PVC-MPs. The in vitro experiments showed that the protein structure and activity of digestive enzymes were changed after adsorption by microplastics. After digestion, the static contact angle of PVC-MPs was decreased, indicating that the hydrophilicity of the PVC-MPs increased, which will increase its mobility in organisms. Cell experiment showed that the altered physicochemical property of PVC-MPs after digestion process also affect its cytotoxicity, including cellular uptake, cell viability, cell membrane integrity, reactive oxygen species levels, and mitochondrial membrane potential. Transcriptome analyses further confirmed the enhanced biotoxic effect of PVC-MPs after digestion treatment. Therefore, the ecological risk of microplastics may be underestimated owing to the interactions of microplastics and digestive tract protein during biological ingestion.

Schlafen 11 triggers innate immune responses through its ribonuclease activity upon detection of single-stranded DNA.

Nucleic acids are major structures detected by the innate immune system. Although intracellular single-stranded DNA (ssDNA) accumulates during pathogen infection or disease, it remains unclear whether and how intracellular ssDNA stimulates the innate immune system. Here, we report that intracellular ssDNA triggers cytokine expression and cell death in a CGT motif-dependent manner. We identified Schlafen 11 (SLFN11) as an ssDNA-activated RNase, which is essential for the innate immune responses induced by intracellular ssDNA and adeno-associated virus infection. We found that SLFN11 directly binds ssDNA containing CGT motifs through its carboxyl-terminal domain, translocates to the cytoplasm upon ssDNA recognition, and triggers innate immune responses through its amino-terminal ribonuclease activity that cleaves transfer RNA (tRNA). Mice deficient in Slfn9, a mouse homolog of SLFN11, exhibited resistance to CGT ssDNA-induced inflammation, acute hepatitis, and septic shock. This study identifies CGT ssDNA and SLFN11/9 as a class of immunostimulatory nucleic acids and pattern recognition receptors, respectively, and conceptually couples DNA immune sensing to controlled RNase activation and tRNA cleavage.

Preparation of chitosan photodynamic antibacterial film loaded with VK3 complex in the preservation of chilled mutton.

To effectively utilize the photodynamic antibacterial ability of vitamin K3 (VK3), by solving the photothermal instability of VK3, it was combined with natural polymers to apply the preservation of chilled mutton. We encapsulated VK3 in the (2-Hydroxypropyl)-ß-cyclodextrin (HP-ß-CD) to construct VK3-HP-ß-CD complex and then introduced the complex to chitosan (CS) and polyvinyl alcohol (PVA) to fabricate an antibacterial film (CS/PVA-VK3-HP-ß-CD film). Through the packaging performance test of the film, the content of VK3-HP-ß-CD was an important factor determining the properties of film including tensile strength, elongation at break, water vapor permeability, water content and water contact angle. Meanwhile, CS/PVA-VK3-HP-ß-CD films could continuously release ROS under light and suspended in dark, thus realizing >99 % antibacterial rate for Escherichia coli and Staphylococcus aureus. In the application experiment of chilled mutton, CS/PVA-VK3-1-HP-ß-CD film could significantly inhibit the increase of total viable count (TVC), pH value (pH) and total volatile base nitrogen (TVB-N) of chilled mutton, and extended its shelf life for at least 12 days. These results indicated that the CS/PVA film with the VK3-HP-ß-CD complex might have promising potential as an antibacterial material for packaging and preserving food.

Comparative transcriptomic analysis revealed important processes underlying the static magnetic field effects on Arabidopsis.

Static magnetic field (SMF) plays important roles in various biological processes of many organisms including plants, though the molecular mechanism remains largely unclear. Here in this study, we evaluated different magnetic setups to test their effects on growth and development on Arabidopsis (Arabidopsis thaliana), and discovered that plant growth was significantly enhanced by inhomogeneous SMF generated by a regular triangular prism magnet perpendicular to the direction of gravity. Comparative transcriptomic analysis revealed that auxin synthesis and signal transduction genes were upregulated by SMF exposure. SMF also facilitated plants to maintain the iron homeostasis. The expression of iron metabolism-related genes was downregulated by SMF, however, the iron content in plant tissues remains relatively unchanged. Furthermore, SMF exposure also helped the plants to reduce ROS level and synergistically maintain the oxidant balance by enhanced activity of antioxidant enzymes and accumulation of nicotinamide. Taken together, our data suggested that SMF is involved in regulating the growth and development of Arabidopsis thaliana through maintaining iron homeostasis and balancing oxidative stress, which could be beneficial for plant survival and growth. The work presented here would extend our understanding of the mechanism and the regulatory network of how magnetic field affects the plant growth, which would provide insights into the development of novel plant synthetic biology technologies to engineer stress-resistant and high-yielding crops.

Cardamomin Inhibits the Proliferation and Tumorigenesis of Bladder Cancer by ESR1 in PI3K/AKT Pathway.

Cardamomin has been widely studied in cancer, but its role in cancer bladder cancer has not been mentioned. In this study, we validated the anti-cancer effect of cardamom and whether its potential mechanism is related to the PI3K/AKT pathway. After treating with different doses of cardamomin, the cytotoxicity was studied by CCK8. Secondly, we analyzed the effect of cardamomin on the proliferation, apoptosis and cell movement. Next, we analyzed the regulation of ESR1 by western blot and its impact on the PI3K/AKT pathway. We also transfected ESR1 overexpression and silencing vectors, and verified the transfection efficiency through RT-qPCR. Further, the specific mechanism of the drug's inhibitory effect on bladder cancer was also determined. We constructed the subcutaneous tumor model in vivo. After cardamomin administration, we mainly analyzed the positive expression of KI67 in tumor tissues by immunohistochemistry, and the apoptotic cells in tumor tissues by TUNEL, and related proteins in PI3K/AKT pathway by western blot. In this paper, cardamomin inhibited cell proliferation and invasion ability, blocked the transition of G0/G1 phase to S phase, and increased apoptotic rate of 5637 and HT1376 cells, as well as raised ESR1 expression. Cardamomin exerted anti-tumor effect through PI3K/AKT pathway. In vivo animal experiments indicated the inhibitory effect of cardamomin on subcutaneous implanted tumor. Cardamomin inhibited the positive expression of KI67 and promoted the TUNEL-positive cells in tumor tissues. Consistent with in vitro assay, cardamomin increased the expression of ESR1 and downregulated the PI3K/AKT pathway. Cardamomin has a significant inhibitory effect on bladder cancer, and upregulate the expression of ESR1 in bladder cancer through PI3K/AKT.

CXCR4-Mediated Codelivery of FLT3 and BCL-2 Inhibitors for Enhanced Targeted Combination Therapy of FLT3-ITD Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is often associated with poor prognosis and survival. Small molecule inhibitors, though widening the treatment landscape, have limited monotherapy efficacy. The combination therapy, however, shows suboptimal clinical outcomes due to low bioavailability, overlapping systemic toxicity and drug resistance. Here, we report that CXCR4-mediated codelivery of the BCL-2 inhibitor venetoclax (VEN) and the FLT3 inhibitor sorafenib (SOR) via T22 peptide-tagged disulfide cross-linked polymeric micelles (TM) achieves synergistic treatment of FLT3-ITD AML. TM-VS with a VEN/SOR weight ratio of 1/4 and T22 peptide density of 20% exhibited an extraordinary inhibitory effect on CXCR4-overexpressing MV4-11 AML cells. TM-VS at a VEN/SOR dosage of 2.5/10 mg/kg remarkably reduced leukemia burden, prolonged mouse survival, and impeded bone loss in orthotopic MV4-11-bearing mice, outperforming the nontargeted M-VS and oral administration of free VEN/SOR. CXCR4-mediated codelivery of BCL-2 and FLT3 inhibitors has emerged as a prospective clinical treatment for FLT3-ITD AML.

Pushing the Limits of Capacitively Coupled Contactless Conductivity Detection for Capillary Electrophoresis.

Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) has proven to be an efficient technique for the separation and detection of charged inorganic, organic, and biochemical analytes. It offers several advantages, including cost-effectiveness, nanoliter injection volume, short analysis time, good separation efficiency, suitability for miniaturization, and portability. However, the routine determination of common inorganic cations (NH4+, K+, Na+, Ca2+, Mg2+, and Li+) and inorganic anions (F-, Cl-, Br-, NO2-, NO3-, PO43-, and SO42-) in water quality monitoring typically exhibits limits of detection of about 0.3-1 µM without preconcentration. This sensitivity often proves insufficient for the applications of CE-C4D in trace analysis situations. Here, we explore methods to push the detection limits of CE-C4D through a comprehensive consideration of signal and noise sources. In particular, we (i) studied the model of C4D and its guiding roles in C4D and CE-C4D, (ii) optimized the bandwidth and noise performance of the current-to-voltage (I-V) converter, and (iii) reduced the noise level due to the strong background signal of the background electrolyte by adaptive differential detection. We characterized the system with Li+; the 3-fold signal-to-noise (S/N) detection limit for Li+ was determined at 20 nM, with a linear range spanning from 60 nM to 1.6 mM. Moreover, the optimized CE-C4D method was applied to the analysis of common mixed inorganic cations (K+, Na+, Ca2+, Mg2+, and Li+), anions (F-, Cl-, Br-, NO2-, NO3-, PO43-, and SO42-), toxic halides (BrO3-) and heavy metal ions (Pb2+, Cd2+, Cr3+, Co2+, Ni2+, Zn2+, and Cu2+) at trace concentrations of 200 nM. All electropherograms showed good S/N ratios, thus proving its applicability and accuracy. Our results have shown that the developed CE-C4D method is feasible for trace ion analysis in water quality control.

Iodine-125 seed inhibits proliferation and promotes apoptosis of cholangiocarcinoma cells by inducing the ROS/p53 axis.

With advances in radioactive particle implantation in clinical practice, Iodine-125 (125I) seed brachytherapy has emerged as a promising treatment for cholangiocarcinoma (CCA), showing good prognosis; however, the underlying molecular mechanism of the therapeutic effect of 125I seed is unclear. To study the effects of 125I seed on the proliferation and apoptosis of CCA cells. CCA cell lines, RBE and HCCC-9810, were treated with reactive oxygen species (ROS) scavenger acetylcysteine (NAC) or the p53 functional inhibitor, pifithrin-α hydrobromide (PFTα). Cell counting kit-8 (CCK-8) assay, 5-bromo-2-deoxy-uridine (BrdU) staining, and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry assay were performed to test the radiation-sensitivity of 125I seed toward CCA cells at different radiation doses (0.4 mCi and 0.8 mCi). 2,7-dichlorofluorescein diacetate (DCF-DA) assay, real-time quantitative polymerase chain reaction (RT-qPCR), and western blot analysis were performed to assess the effect of 125I seed on the ROS/p53 axis. A dose-dependent inhibitory effect of 125I seeds on the proliferation of CCA cells was observed. The 125I seed promoted apoptosis of CCA cells and induced the activation of the ROS/p53 pathway in a dose-dependent manner. NAC or PFTα treatment effectively reversed the stimulatory effect of 125I seed on the proliferation of CCA cells. NAC or PFTα suppressed apoptosis and p53 protein expression induced by the 125I seed. 125I seed can inhibit cell growth mainly through the apoptotic pathway. The mechanism may involve the activation of p53 and its downstream apoptotic pathway by up-regulating the level of ROS in cells.

Synergetic effect of green synthesized NZVI@Chitin-modified ZSM-5 for efficient oxidative degradation of tetracycline.

The aggregation and limited activity of nanoscale zero-valent iron (NZVI) in aqueous media hinder its practical application. In this study, a cost-effective, environmentally friendly, robust, and efficient synthesis method for NZVI-based composite was developed. NZVI@Chitin-modified ZSM-5 (NZVI@C-ZSM) composite was facilely and greenly synthesized by loading NZVI into alkali-modified ZSM-5 molecular sieves after modifying with chitin as a surfactant and binder. NZVI@C-ZSM exhibited remarkable efficacy in TC removal, achieving a removal efficiency of 97.72% within 60 min. Compared with pristine NZVI, NZVI@C-ZSM demonstrated twice the removal efficiency, indicating that NZVI@C-ZSM effectively improved the dispersion and stability of NZVI. This enhancement provided more reactive sites for generating reactive oxygen species (ROS), significantly boosting catalytic activity and durability while reducing the potential risk of secondary pollution. An improved two-parameter pseudo-first-order kinetic model was used to effectively characterize the reaction kinetics. The mechanism for TC removal primarily involved an adsorption process and chemical oxidation-reduction reactions induced by hydroxyl radicals (•OH) and superoxide radicals (•O2-). Three potential degradation pathways for TC were suggested. Furthermore, NZVI@C-ZSM exhibited good resistance to interference, suggesting its broad potential for practical applications in complex environmental conditions. This study offers a viable material and method for addressing the issue of antibiotic-contaminated water, with potential applications in water resource management.

Right ventricular stiffening and anisotropy alterations in pulmonary hypertension: Mechanisms and relations to function.

Aims: Pulmonary hypertension (PH) results in an increase in RV afterload, leading to RV dysfunction and failure. The mechanisms underlying maladaptive RV remodeling are poorly understood. In this study, we investigated the multiscale and mechanistic nature of RV free wall (RVFW) biomechanical remodeling and its correlations with RV function adaptations. Methods and Results: Mild and severe models of PH, consisting of hypoxia (Hx) model in Sprague-Dawley (SD) rats (n=6 each, Control and PH) and Sugen-hypoxia (SuHx) model in Fischer (CDF) rats (n=6 each, Control and PH), were used. Organ-level function and tissue-level stiffness and microstructure were quantified through in-vivo and ex-vivo measures, respectively. Multiscale analysis was used to determine the association between fiber-level remodeling, tissue-level stiffening, and organ-level dysfunction. Animal models with different PH severity provided a wide range of RVFW stiffening and anisotropy alterations in PH. Decreased RV-pulmonary artery (PA) coupling correlated strongly with stiffening but showed a weaker association with the loss of RVFW anisotropy. Machine learning classification identified the range of adaptive and maladaptive RVFW stiffening. Multiscale modeling revealed that increased collagen fiber tautness was a key remodeling mechanism that differentiated severe from mild stiffening. Myofiber orientation analysis indicated a shift away from the predominantly circumferential fibers observed in healthy RVFW specimens, leading to a significant loss of tissue anisotropy. Conclusion: Multiscale biomechanical analysis indicated that although hypertrophy and fibrosis occur in both mild and severe PH, certain fiber-level remodeling events, including increased tautness in the newly deposited collagen fibers and significant reorientations of myofibers, contributed to excessive biomechanical maladaptation of the RVFW leading to severe RV-PA uncoupling. Collagen fiber remodeling and the loss of tissue anisotropy can provide an improved understanding of the transition from adaptive to maladaptive remodeling. Translational perspective: Right ventricular (RV) failure is a leading cause of mortality in patients with pulmonary hypertension (PH). RV diastolic and systolic impairments are evident in PH patients. Stiffening of the RV wall tissue and changes in the wall anisotropy are expected to be major contributors to both impairments. Global assessments of the RV function remain inadequate in identifying patients with maladaptive RV wall remodeling primarily due to their confounded and weak representation of RV fiber and tissue remodeling events. This study provides novel insights into the underlying mechanisms of RV biomechanical remodeling and identifies the adaptive-to-maladaptive transition across the RV biomechanics-function spectrum. Our analysis dissecting the contribution of different RV wall remodeling events to RV dysfunction determines the most adverse fiber-level remodeling to RV dysfunction as new therapeutic targets to curtail RV maladaptation and, in turn, RV failure in PH.

Active visual continuous seam tracking based on adaptive feature detection and particle filter tracking.

Welding seam tracking based on online programming is the future trend of intelligent production. However, most of the existing image processing methods have certain limitations in the adaptability, accuracy, and robustness of weld feature point detection. The online welding method of gas metal arc welding (GMAW) based on active vision sensing is studied in this paper. The Steger sub-pixel detection method is used to guarantee the accuracy of feature point extraction, and a self-adaptive search window and self-adaptive slope extraction are proposed on this basis. The self-adaptive window is generated according to the linear information of the weld area, and the scale factor and range threshold constraint are added to realize the real-time detection of the weld feature information. Screening the center pixel of the laser stripe in the self-adaptive window of the current frame by the initial slope or the self-adaptive slope of the previous frame, the linear information of the weld area is obtained. The self-adaptive slope of the current frame is fitted by the random sampling consistency method, and the pixel margin is retained to adapt to the linear detection of different continuous welds. When arc light and other serious interference make it difficult to obtain weld information, a particle filter is used to make the best prediction of the weld position. Finally, the welding robot platform based on laser vision sensing was built to test various continuous welds of the butt weld, fillet weld, and lap weld. Experimental results show that the detection speed is 27 ms, and the accuracy of detection and tracking can respectively reach 0.03 mm and 0.78 mm, which meets the requirements of weld detection and tracking.

Performance evaluation and comparative research of underwater wireless optical communication system by using different structured beams.

Structured beams have attracted increasing interest in free-space and fiber-based optical communications. Underwater wireless optical communication (UWOC) is becoming a prospective technique in marine exploration. We investigated UWOC performance using different representative structured beams. The transmission performances of the Gaussian, Bessel-Gaussian (BG), Ince-Gaussian (IG), and radially polarized Gaussian (RPG) beams were experimentally demonstrated and evaluated in underwater channels subjected to thermal gradient. The experimental results show that the BG, IG, and RPG perform better against the thermal gradient. Compared with the Gaussian beams, the beam wanders of BG, IG, and RPG beams under the thermal gradient have been reduced by 56.9%, 8.2%, and 59%, the scintillation indices have been decreased by 12.8%, 17.3%, and 28.9%, and the BER performance of the BG, IG, and RPG beams have been improved by ∼5.5, ∼3.7, and ∼5.2d B at the forward error correction threshold (FEC threshold). Based on the above results, the RPG beam is a more promising light source for UWOC. The experimental results provide a promising beam choice for UWOC.