Search Results (77)

Quantification of optic disc microvasculature is crucial for diagnosing various ocular diseases. However, accurate quantification of the microvasculature requires the exclusion of large vessels, such as the central artery and vein, when present. To address the challenge of ineffective learning of edge information, which arises from the adhesion and transposition of large vessels in the optic disc, we developed a segmentation model that generates high-quality edge information in optic disc slices. By integrating dual-stream learning with channel-spatial attention and multi-level attention mechanisms, our model effectively learns both the target’s primary structure and fine details. Compared to state-of-the-art methods, our proposed approach demonstrates superior performance in segmentation accuracy. Superior results were obtained when the model was tested on OCTA images of the optic disc from 10 clinical patients. This underscores the significant contribution of our method in achieving clearly defined multi-task learning while substantially enhancing inference speed. Full article

Eutectic high-entropy alloys (EHEAs) exhibit excellent casting properties and comprehensive mechanical performance, making them suitable for fabricating spatial engineering components using additive manufacturing techniques. However, the rapid solidification process also leads to increased internal stress and reduced structural stability in the components. Therefore, this study focuses on the AlFeCoCrNi_2.1 EHEA as the research subject, utilizing laser additive manufacturing to fabricate components and systematically investigating the influence of heat treatment processes on the microstructure and mechanical properties of the components. The research demonstrates that low-temperature heat treatment (700 °C and below) acts as a stress relief-annealing process for the components. The yield strength decreased from 1003.2 MPa to 742.1 MPa. At 900 °C heat treatment, the constraining effect between recrystallized grains and surrounding grains outweighs the dislocation release effect caused by recrystallization, resulting in an increase in dislocation density. The yield strength remained approximately stable at around 730 MPa. High-temperature heat treatment (1100 °C) alters the orientation of phase structures and fragments the two-phase structure through recrystallization, leading to generally stable mechanical properties of the components. The yield strength of the cast components further decreased to 582.6 MPa, while that of the LMD-fabricated parts retained stability at approximately 730 MPa. Full article

Research on modular robots for space exploration has primarily focused on reconfiguration, with limited attention given to the maneuverability in space environment, which is essential for harnessing the advantages of reconfiguration. In this paper, a modular snake-like robot (MSR) is designed, which is expected to emulate a snake to navigate complex environments and employ the reconfiguration capability for on-site shape-shifting. To this end, a snake-like motion analysis and planning method is proposed for MSR. Firstly, we explore the feasibility of utilizing modules in realizing snake-like motion, including functional compatibility and structural constraints. Secondly, we analyze the kinematics of MSR and design joint coordination motion schemes to meet the requirements of snake-like motion. Finally, a path planning method based on reinforcement learning is proposed, which fully considers the motion characteristics and the structural constraints. Through motion analysis and planning, a balance between environmental adaptability and versatility can be achieved. Simulations of comparisons and potential applications further demonstrate the significant advantages of MSR in space exploration. Full article

Some studies have reported the microstructure evolution of nickel-based superalloys during isothermal forging (IF). However, most of them have not taken into account the microstructure evolution during the preheating stage in manufacturing processes. Investigating the microstructure evolution mechanisms during preheating of nickel-based superalloy can provide a more accurate characterization of the initial microstructures prior to IF. In this study, the evolution of grain structure, participation phase, and twins in a hot extruded nickel-based superalloy are examined during heat treatment at the temperature range of 1050~1140 °C and 5~180 min. Also, the interaction mechanisms among the above microstructures are analyzed. Experimental results demonstrate that higher temperature significantly accelerates the dissolution of the primary γ′ (γ′_p) phase and grain growth. At 180 min, the average grain size rapidly grows from 4.59 μm at 1080 °C to 14.09 μm at 1110 °C. In contrast, the impact of holding time on the microstructure diminishes after 30 min. At 1080 °C, the average grain size grows from 2.52 μm at 5 min to 4.95 μm at 30 min, after which it remains relatively stable. Initially, the γ′_p phase hinders grain boundary migration and inhibits grain growth. However, its complete dissolution at high temperatures significantly promotes grain growth. Careful selection of preheating temperature can mitigate rapid grain growth before forging. Additionally, twins not only refine grains through nucleation and segmentation, but also hinder grain boundary migration in regions with high dislocation density, thereby alleviating grain growth. A model detailing the dissolution of the γ′_p phase during preheating is developed, with a correlation coefficient and average absolute relative error of 0.9947 and 9.15%, respectively. This model provides theoretical support for optimizing preheating temperatures and estimating initial microstructures prior to IF. Full article

The ionic soil stabilizer (ISS) can synergistically enhance the mechanical properties and improve the engineering characteristics of iron tailings soil in conjunction with cementitious materials such as cement. In this paper, the influence of ISS on the cement hydration process and the charge repulsion between iron tailings soil particles was studied. By means of Isothermal calorimetry, X-ray diffraction (XRD), Scanning electron microscope (SEM), and Low-field nuclear magnetic resonance microscopic analysis methods such as (LF-NMR), X-ray photoelectron spectroscopy (XPS), Non-evaporable water content and Zeta potential were used to clarify the mechanism of ISS-enhanced cement stabilization of the mechanical properties of iron tailings soil. The results show that in the cement system, ISS weakens the mechanical properties of cement mortar. When ISS content is 1.67%, the 7 d compressive strength of cement mortar decreases by 59.8% compared with the reference group. This retardation arises due to carboxyl in ISS forming complexes with Ca²⁺, creating a barrier on cement particle surfaces, hindering the hydration reaction of the cement. In the cement-stabilized iron tailings soil system, ISS has a positive modification effect. At 0.33% ISS, compared with the reference group, the maximum dry density of the samples increased by 6.5%, the 7 d unconfined compressive strength increased by 35.3%, and the porosity decreased from 13.58% to 11.85%. This is because ISS reduces the double electric layer structure on the surface of iron tailings soil particles, reduces the electrostatic repulsion between particles, and increases the compactness of cement-stabilized iron tailings soil. In addition, the contact area between cement particles increases, the reaction energy barrier height decreases, the formation of Ca(COOH)₂ reduces, and the retarding effect on hydration weakens. Consequently, ISS exerts a beneficial effect on augmenting the mechanical performance of cement-stabilized iron tailings soil. Full article

The effects of the designed equal channel angular pressing (ECAP) procedures on microstructures, mechanical properties and corrosion resistances of newly developed nano-MgO/Mg–Zn–Ca composite materials have been investigated in this study. The die channel angles selected by the ECAP processes are 90°and 120°, and the corresponding composite materials are kept for 15 min in the ECAP mold at 300 °C before 1, 4, and 8 passes through route$B_C$. It can be understood that the sizes of grains and second phases were significantly reduced because of continuous dynamic recrystallization (C-DRX) and mechanical shearing, and the ECAP process with the die angle of 90° shows more evidence of grain refinement owing to the higher shear stress. The obtained mechanical properties stipulated that both the yield and ultimate strength were improved after ECAP, which is related to the interaction of grain and texture evolution, while the elongation increases drastically from 14% (as-extruded state) to 34% (ECAP-ed state). Meanwhile, the improvement of corrosion resistance by microstructural evolution is more significant than adverse effects originating from the internal defects of the material itself as well as the defects originating from the number of passes. Ultimately, the conclusions were made based on the results regarding performance improvement by the optimized parameters designed and utilized in ECAP for this novel Mg composite material. Full article

Camphora Fabr. is a genus in the family Lauraceae, comprising over 20 tropical and subtropical tree species. Since the genera Camphora and Cinnamomum Schaeff. were described, there has been a long-lasting controversy regarding the phylogenetic relationships among taxa in both genera. In particular, phylogenetic inferences derived from plastid data remain debated, with varying hypotheses proposed and occasional disputes concerning the monophyly of Camphora taxa. To further investigate the relationships, We analyzed plastomes and nuclear ribosomal cistron sequences (nrDNA) of 22 Camphora taxa, 15 Cinnamomum taxa, and 13 representative taxa of related genera. The Camphora plastomes range from 152,745 to 154,190 bp, with a GC content of 39.1% to 39.2%. A total of 128 genes were identified in the Camphora plastomes, including 84 protein-coding genes, 8 rRNA genes, and 36 tRNA genes. A total of 1130 SSR loci were detected from plastomes of Camphora, and A/T base repeats looked like the most common. Comparative analyses revealed that the plastomes of Camphora exhibit high similarity in overall structure. The loci ycf1, ycf2, trnK (UUU), psbJ-psbL, and ccsA-ndhD were identified as candidate DNA barcodes for these taxa. Plastome phylogenetic analysis revealed that Camphora is not monophyletic, whereas the nrDNA dataset supported the monophyly of Camphora. We propose that intergeneric hybridization may underlie the observed discordance between plastid and nuclear data in Camphora, and we recommend enhanced taxonomic sampling and precise species identification to improve phylogenetic resolution and accuracy. Full article

This review explores the critical role of exosomes in promoting angiogenesis, a key factor in skin flap survival. Skin flaps are widely used in reconstructive surgery, and their survival depends heavily on the formation of new blood vessels. Exosomes, small extracellular vesicles secreted by various cells, have emerged as important mediators of intercellular communication and play a crucial role in biological processes such as angiogenesis. Compared to traditional methods of promoting angiogenesis, exosomes show more selective and targeted therapeutic potential as they naturally carry angiogenic factors and can precisely regulate the angiogenesis process. The review will delve into the molecular mechanisms by which exosomes facilitate angiogenesis, discuss their potential therapeutic applications in enhancing skin flap survival, and explore future research directions, particularly the challenges and prospects of exosomes in clinical translation. By highlighting the unique advantages of exosomes in skin flap survival, this review provides a new perspective in this field and opens up new research directions for future therapeutic strategies. Full article

Fe₂B is a potentially promising electrocatalyst for the oxygen evolution reaction (OER) due to its excellent electronic conductivity, which is superior to that of traditional oxide catalysts. However, the activity of Fe₂B is still not satisfactory. In this study, meta-stable microstructure stacking faults (SFs) were incorporated into Fe₂B through a one-step high-pressure and high-temperature (HPHT) method. Pressure suppressed atomic diffusion but formed SFs when the grain grew. Fe₂B with SFs exhibited remarkable OER activity, with low overpotential values of only 269 and 344 mV required to reach current densities of 10 and 100 mA cm⁻², respectively; because of the presence of SFs, the overpotential for the OER was reduced to only 67.7% of that of Fe₂B without SFs at 10 mA cm⁻². Theoretical and experimental investigations confirmed that these SFs regulate the d-band center of Fe₂B toward the Fermi level, optimizing the catalytic site activity. Furthermore, SFs reduced the charge transfer between Fe atoms and boron (B) atoms, increasing the number of free electrons in the structure and thereby increasing conductivity. Finally, this study suggests a strategy to construct microstructures in crystals, providing new insights into designing excellent catalysts via microstructure engineering. Full article

The deep coal seams in the southern Sichuan region contain abundant coalbed methane resources. Determining the characteristics and distribution patterns of coal structures in this study area, and analyzing their impact on pore and fracture structures within coal reservoirs, holds substantial theoretical and practical significance for advancing coal structure characterization methods and the efficient development of deep coalbed methane resources. This paper quantitatively characterizes coal structures through coal core observations utilizing the Geological Strength Index (GSI) and integrates logging responses from different coal structures to develop a quantitative coal structure characterization model based on logging curves. This model predicts the spatial distribution of coal structures, while nitrogen adsorption data are used to analyze the development of pores and fractures in different coal structures, providing a quantitative theoretical basis for accurately characterizing deep coal seam features. Results indicate that density, gamma, acoustic, and caliper logging are particularly sensitive to coal structure variations and that performing multiple linear regression on logging data significantly enhances the accuracy of coal structure identification. According to the model proposed in this paper, primary-fragmented structures dominate the main coal seams in the study area, followed by fragmented structures. Micropores and small pores predominantly contribute to the volume and specific surface area of the coal samples, with both pore volume and specific surface area increasing alongside the degree of coal fragmentation. Additionally, the fragmentation of coal structures generates more micropores, enhancing pore volume and suggesting that tectonic coal has a greater adsorption capacity. This study combines theoretical analysis with experimental findings to construct a coal structure characterization model for deep coal seams, refining the limitations of logging techniques in accurately representing deep coal structures. This research provides theoretical and practical value for coal seam drilling, fracturing, and reservoir evaluation in the southern Sichuan region. Full article

As a common fungal disease, powdery mildew (PM) is one of the main diseases that harm the growth and development of cucumbers. Understanding the types of pathogenic fungus and analysis of the genetic and molecular mechanisms of cucumber resistance to PM at the molecular level are important when breeding disease-resistant varieties. The present review summarizes the hazards, prevention, and control of PM, and it discusses resistance inheritance rules, molecular markers, quantitative trait locus (QTL) mapping, gene cloning, omics, and gene editing technology, providing research insights on cucumber breeding varieties resistant to PM. Full article

The shrub/dwarf tree Haloxylon ammodendron is a prevalent woody plant used to combat desertification in the arid and semi-arid regions of northwestern China. Despite its drought resistance, artificial stands of this species experience significant degradation approximately ten years post-afforestation. Stumping, which involves cutting a portion of the above-ground part of shrubs/trees, is a common practice aimed at reducing water consumption and enhancing the growth of these stands. However, the impact of stumping on the sap flow of H. ammodendron remain inadequately understood, posing challenges to the sustainable management of these artificial stands. In this study, we monitored the sap flow of H. ammodendron subjected to various stumping treatments in the Ulan Buh Desert using the PS-TDP8 tree sap flow monitoring system. Concurrently, we measured several meteorological factors with an automatic weather station. We examined the changes in sap flow velocity following stumping and its response to meteorological factors to elucidate water use during growth. Our findings indicate that both the change in sap flow velocity and characteristics were closely associated with the degree of stumping. The initiation time of sap flow for H. ammodendron under different stumping treatments was earlier than that of the control group. The daily mean value and daily accumulation of sap flow followed the order: 50% stumping > control (no stumping) > 75% stumping > 100% stumping. Sap flow velocity and daily sap flow accumulation increased at 50% stumping but decreased at 75% and 100% stumping. Stumping altered the relationships between sap flow velocity and meteorological factors, with the correlation coefficient between these variables decreasing as the degree of stumping increased. The sap flow following stumping was primarily influenced by both the degree of stumping and meteorological factors. These results may contribute to a better understanding of water transport during the growth of H. ammodendron following stumping. Full article

Drawing inspiration from the structural resemblance between a natural product N-(3-carboxypropyl)-2-acetylpyrrole and phenylbutyric acid, a pioneer HDAC inhibitor evaluated in clinical trials, we embarked on the design and synthesis of a novel array of HDAC inhibitors containing an N-linked 2-acetylpyrrole cap by utilizing the pharmacophore fusion strategy. Among them, compound 20 exhibited potential inhibitory activity on HDAC1, and demonstrated notable potency against RPMI-8226 cells with an IC₅₀ value of 2.89 ± 0.43 μM, which was better than chidamide (IC₅₀ = 10.23 ± 1.02 μM). Western blot analysis and Annexin V-FTIC/propidium iodide (PI) staining showed that 20 could enhance the acetylation of histone H3, as well as remarkably induce apoptosis of RPMI-8226 cancer cells. The docking study highlighted the presence of a hydrogen bond between the carbonyl oxygen of the 2-acetylpyrrole cap group and Phe198 of the HDAC1 enzyme in 20, emphasizing the crucial role of introducing this natural product-inspired cap group. Molecular dynamics simulations showed that the docked complex had good conformational stability. The ADME parameters calculation showed that 20 possesses remarkable theoretical drug-likeness properties. Taken together, these results suggested that 20 is worthy of further exploration as a potential HDAC-targeted anticancer drug candidate. Full article

The liver plays an important role in regulating lipid metabolism in animals. This study investigated the function and mechanism of lncLLM in liver lipid metabolism in hens at the peak of egg production. The effect of lncLLM on intracellular lipid content in LMH cells was evaluated by qPCR, Oil Red O staining, and detection of triglyceride (TG) and cholesterol (TC) content. The interaction between lncLLM and MYH9 was confirmed by RNA purification chromatin fractionation (CHIRP) and RNA immunoprecipitation (RIP) analysis. The results showed that lncLLM increased the intracellular content of TG and TC and promoted the expression of genes related to lipid synthesis. It was further found that lncLLM had a negative regulatory effect on the expression level of MYH9 protein in LMH cells. The intracellular TG and TC content of MYH9 knockdown cells increased, and the expression of genes related to lipid decomposition was significantly reduced. In addition, this study confirmed that the role of lncLLM is at least partly through mediating the ubiquitination of MYH9 protein to accelerate the degradation of MYH9 protein. This discovery provides a new molecular target for improving egg-laying performance in hens and treating fatty liver disease in humans. Full article

Activating enhancer-binding protein 2 (AP-2) is a family of transcription factors (TFs) that play crucial roles in regulating embryonic and oncogenic development. In addition to splice isoforms, five major family members encoded by the TFAP2A/B/C/D/E genes have been identified in humans, i.e., AP-2α/β/γ/δ/ε. In general, the first three TFs have been studied more thoroughly than AP-2δ or AP-2ε. Currently, there is a relatively limited body of literature focusing on the AP-2 family in the context of gastroenterological research, and a comprehensive overview of the existing knowledge and recommendations for further research directions is lacking. Herein, we have collected available gastroenterological data on AP-2 TFs, discussed the latest medical applications of each family member, and proposed potential future directions. Research on AP-2 in gastrointestinal tumors has predominantly been focused on the two best-described family members, AP-2α and AP-2γ. Surprisingly, research in the past decade has highlighted the importance of AP-2ε in the drug resistance of gastric cancer (GC) and colorectal cancer (CRC). While numerous questions about gastroenterological disorders await elucidation, the available data undoubtedly open avenues for anti-cancer targeted therapy and overcoming chemotherapy resistance. In addition to gastrointestinal cancers, AP-2 family members (primarily AP-2β and marginally AP-2γ) have been associated with other health issues such as obesity, type 2 diabetes, liver dysfunction, and pseudo-obstruction. On the other hand, AP-2δ has been poorly investigated in gastroenterological disorders, necessitating further research to delineate its role. In conclusion, despite the limited attention given to AP-2 in gastroenterology research, pivotal functions of these transcription factors have started to emerge and warrant further exploration in the future. Full article