Scanning Electron Microscopy Observations Research Articles

Light-curable urushiol enhanced bisphenol A glycidyl dimethacrylate dentin bonding agent

ObjectivesThe low durability of composite resin restorations can be attributed to the degradation of the resin dentin bonding interface. Owing to the presence of hydrophilic components in the adhesive, the integrity of the resin dentin bonding interface is easily compromised, which, in turn, leads to a reduction in bond strength. The hydrophilic nature of the adhesive leads to water sorption, phase separation, and leaching of the resin component. Therefore, hydrophobic adhesives could effectively be used to stabilize the integrity and durability of the resin dentin bonding interface. MethodsWe synthesized a novel hydrophobic dentin adhesive by partially replacing bisphenol A glycidyl dimethacrylate (Bis-GMA) with a light-curable urushiol monomer. The properties of the produced adhesive, including the degree of conversion, viscosity, contact angle, water sorption/solubility, and mechanical strength, were comprehensively examined and compared to those of the commercially adhesive Adper Single Bond2 as a positive control. The adhesive properties were determined using microtensile bond strength measurements, laser confocal microscopy, scanning electron microscopy observations, and nanoleakage tests. Finally, the novel adhesive was subjected to biocompatibility testing to determine its potential cytotoxicity. ResultsAt a light-curable urushiol content of 20 %, the synthesized adhesive exhibited high degrees of conversion and hydrophobicity, low cytotoxicity, good mechanical properties, and outstanding adhesive strength. ConclusionsThe introduction of the light-curable urushiol into dentin adhesives can significantly enhance their hydrophobic, mechanical, and bonding properties, demonstrating potential to significantly improve restoration longevity. Clinical significanceThe integration of light-curable urushiol has endowed the experimental adhesives with several enhanced functionalities. These notable benefits underscore the suitability of this monomer for expanded applications in clinical practice.

Cutibacterium acnes biofilm formation is influenced by bone microenvironment, implant surfaces and bacterial internalization

BackgroundThe bacterial persistence, responsible for therapeutic failures, can arise from the biofilm formation, which possesses a high tolerance to antibiotics. This threat often occurs when a bone and joint infection is diagnosed after a prosthesis implantation. Understanding the biofilm mechanism is pivotal to enhance prosthesis joint infection (PJI) treatment and prevention. However, little is known on the characteristics of Cutibacterium acnes biofilm formation, whereas this species is frequently involved in prosthesis infections.MethodsIn this study, we compared the biofilm formation of C. acnes PJI-related strains and non-PJI-related strains on plastic support and textured titanium alloy by (i) counting adherent and viable bacteria, (ii) confocal scanning electronic microscopy observations after biofilm matrix labeling and (iii) RT-qPCR experiments.ResultsWe highlighted material- and strain-dependent modifications of C. acnes biofilm. Non-PJI-related strains formed aggregates on both types of support but with different matrix compositions. While the proportion of polysaccharides signal was higher on plastic, the proportions of polysaccharides and proteins signals were more similar on titanium. The changes in biofilm composition for PJI-related strains was less noticeable. For all tested strains, biofilm formation-related genes were more expressed in biofilm formed on plastic that one formed on titanium. Moreover, the impact of C. acnes internalization in osteoblasts prior to biofilm development was also investigated. After internalization, one of the non-PJI-related strains biofilm characteristics were affected: (i) a lower quantity of adhered bacteria (80.3-fold decrease), (ii) an increase of polysaccharides signal in biofilm and (iii) an activation of biofilm gene expressions on textured titanium disk.ConclusionTaken together, these results evidenced the versatility of C. acnes biofilm, depending on the support used, the bone environment and the strain.

Delamination bridging response of Z‐pins under mixed mode loading: The influence of carbon and Kevlar Z‐pins

AbstractThis paper presents the effect of varying the type of Z‐pin on the delamination bridging performance of unidirectional composite laminates. Carbon and Kevlar Z‐pins were inserted in thick composite laminates using the pre‐hole insertion Z‐pinning process and their bridging performance characterized across the different mode‐mixity range. The bridging response indicated that Kevlar Z‐pin experienced load reduction driven by interfacial friction (Stage III), which was absent in the Carbon Z‐pin. When Mode II dominated the bridging crack, Kevlar Z‐pin showed partial pullout and fiber shear cracking, while the Carbon Z‐pin exhibited clean transverse fracture. Although the bridging load obtained by the Carbon Z‐pin was twice that of Kevlar Z‐pin, the Kevlar Z‐pin provided a higher interlaminar fracture energy. The superior bridging performance of Kevlar Z‐pin is correlated with the enhanced ductility. Moreover, the resin‐rich area was involved in deformation and provided the extra axial load of Z‐pin.Highlights The comparison of mixed‐mode bridging mechanism between Kevlar Z‐pin and Carbon Z‐pin. Reveal the variation of multi‐directional load and energy consumption with mixed‐mode angle in thick laminates. Detailed scanning electron microscope observation to understand failure characteristics of ductile Z‐pin. Evidence that the extra axial load of Z‐pin provided by resin‐rich area.

Designing a Stable Alloy Interlayer on Li Metal Anodes for Fast Charging of All-Solid-State Li Metal Batteries

The deposition of a thin LixSny alloy layer by plasma vapor deposition (PVD) on the surface of a Li foil is reported. The formation of a Li-rich alloy is confirmed by the volume expansion (up to 380%) of the layer and by the disappearance of metallic Sn peaks in the X-ray diffractogram. The layer has a much higher hardness than bare Li and can withstand aggressive cycling at 1C. Post-mortem scanning electron microscope observations revealed that the alloy layer remains intact even after fast cycling for hundreds of cycles. A concept of double modification by adding a thin ceramic/polymer layer deposited by a doctor blade on top of the LixSny layer was also reported to be efficient to reach long-term stability for 500 cycles at C/3. Finally, a post-treatment after Sn deposition consisting of a plasma cleaning of the LixSny alloy layer led to a strong improvement in the cycling performance at 1C. The surface is smoother and less oxidized after this treatment. The combination of a Li-rich alloy interlayer, the increase in hardness at the electrolyte/Li interface, and the absence of dissolution of the layer during cycling at high C-rates are reasons for such an improvement in electrochemical performance.

Scanning Acoustic Microscopy Characterization of Cold-Sprayed Coatings Deposited on Grooved Substrates

AbstractThe effect of non-planar substrate surface on homogeneity and quality of cold-sprayed (CS) deposits was studied by scanning acoustic microscopy (SAM). Fe coatings were cold-sprayed onto Al substrates containing artificially introduced grooves of square- and trapezoid-shaped geometries, with flat or cylindrical bottoms. The Al substrates were either wrought or cold-sprayed, to comprehend their prospective influence on the Fe coatings buildup. SAM was then used to assess morphological properties of the materials from the cross-view and top-view directions. The microstructure below the surface of the studied samples was visualized by measuring the amplitudes of the reflection echoes and the velocity of the ultrasonic waves. The SAM analysis revealed that the regions of coating imperfections around the grooves are larger than what is suggested by standard scanning electron microscopy (SEM) observations. Furthermore, we found that the seemingly non-influenced coating regions that appear perfectly homogeneous and dense in SEM do, in fact, possess heterogeneous microstructure associated with the individual CS nozzle passes.

Quaternary Zinc Alloys with Magnesium, Calcium and Strontium after Hydrostatic Extrusion-Microstructure and Its Impact on Mechanical and Corrosion Properties.

The development of bioabsorbable implants from Zn alloys is one of the main interests in the new generation of biomaterials. The main drawbacks of Zn-based materials are their insufficient mechanical properties. In the presented studies, a quaternary alloy composed of zinc with magnesium (0.2-1 wt. %), calcium (0.1-0.5 wt. %) and strontium (0.05-0.5 wt. %) was prepared by gravity casting followed by hot extrusion and then by hydrostatic extrusion. Microstructural characterization using scanning electron microscopy (SEM) and X-ray diffraction (XRD) phase analysis was performed. The mechanical properties were examined, using static tensile tests. Corrosion properties were analyzed using immersion tests. Samples were immersed in Hanks' solution (temperature = 37 °C, pH = 7.4) for 14 days. All alloys were subjected after corrosion to SEM observations on the surface and cross-section. The corrosion rate was also calculated. The microstructure of the investigated quaternary alloy consists of the α-Zn grains and intermetallic phases Mg2Zn11, CaZn13 and SrZn13 with different grain sizes and distribution, which impacted both mechanical and corrosion properties. Thanks to the alloying by the addition of Mg, Ca, and Sr and plastic deformation using hydrostatic extrusion, outstanding mechanical properties were obtained along with improvement in uniformity of corrosion rate.

Biocontrol potential and growth-promoting effect of endophytic fungus Talaromyces muroii SD1-4 against potato leaf spot disease caused by Alternaria alternata

BackgroundAlternaria alternata is the primary pathogen of potato leaf spot disease, resulting in significant potato yield losses globally. Endophytic microorganism-based biological control, especially using microorganisms from host plants, has emerged as a promising and eco-friendly approach for managing plant diseases. Therefore, this study aimed to isolate, identify and characterize the endophytic fungi from healthy potato leaves which had great antifungal activity to the potato leaf spot pathogen of A. alternata in vitro and in vivo.ResultsAn endophytic fungal strain SD1-4 was isolated from healthy potato leaves and was identified as Talaromyces muroii through morphological and sequencing analysis. The strain SD1-4 exhibited potent antifungal activity against the potato leaf spot pathogen A. alternata Lill, with a hyphal inhibition rate of 69.19%. Microscopic and scanning electron microscope observations revealed that the strain SD1-4 grew parallel to, coiled around, shrunk and deformed the mycelia of A. alternata Lill. Additionally, the enzyme activities of chitinase and β-1, 3-glucanase significantly increased in the hyphae of A. alternata Lill when co-cultured with the strain SD1-4, indicating severe impairment of the cell wall function of A. alternata Lill. Furthermore, the mycelial growth and conidial germination of A. alternata Lill were significantly suppressed by the aseptic filtrate of the strain SD1-4, with inhibition rates of 79.00% and 80.67%, respectively. Decrease of leaf spot disease index from 78.36 to 37.03 was also observed in potato plants treated with the strain SD1-4, along with the significantly increased plant growth characters including plant height, root length, fresh weight, dry weight, chlorophyll content and photosynthetic rate of potato seedlings.ConclusionThe endophyte fungus of T. muroii SD1-4 isolated from healthy potato leaves in the present study showed high biocontrol potential against potato leaf spot disease caused by A. alternata via direct parasitism or antifungal metabolites, and had positive roles in promoting potato plant growth.

The Preparation and Properties of a Hydrogen-Sensing Field-Effect Transistor with a Gate of Nanocomposite C-Pd Film

The objective of this paper is to evaluate the effect of a nanostructured C-Pd film deposited in the gate area of a field-effect transistor (FET) with a carbon–palladium composite gate (C-Pd/FET) on the hydrogen-sensing properties of the transistor. The method of preparing a field-effect transistor (FET) with a C-Pd film deposited as a gate and the properties of such a transistor and the film itself are presented. The C-Pd film deposited by PVD method on the gate area serves as an active layer. The PVD process was carried out in a dynamic vacuum of 10−5 mbar from two separated sources—one containing fullerenes (C60) and the other containing palladium acetate. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS, EDX) and electrical property studies were used to the characterize C-Pd films and FET/C-Pd structures. SEM observations revealed the topography of C-Pd films and FET/C-Pd transistors. EDS/EDX microanalysis was applied to visualize the arrangement of elements on the studied surfaces. The changes in electrical properties (resistance and relative resistance) due to the presence of hydrogen were studied in a designed and computerized experimental set-up. The enhanced properties of the FET/C-Pd transistor are demonstrated in terms of hydrogen detection.

Electrospun film polyvinyl alcohol/chitosan loaded with cinnamon essential oil and inhibitory effects on polyphenol oxidase and dominant spoilage bacteria from Pacific white shrimp

Pacific white shrimp (Litopenaeus vannamei) is prone to melanosis and spoilage during refrigeration. To develop an active packaging material with inhibitory effects on polyphenol oxidase (PPO) (related with melanosis) and specific spoilage organisms of refrigerated spoilage Litopenaeus vannamei (Lv-SSOs), one degradable polyvinyl alcohol-chitosan (PVA-CS) fibrous mats encapsulating cinnamon essential oil (CEO) were fabricated by electrospinning. Compared to PVA-CS, the transparency, tensile strength and water contract angle of CEO-loaded electrospun film (CEO/PVA-CS) were all significant increased. CEO molecules uniformly dispersed between PVA-CS fiber bundles without any visible gaps under scanning electron microscopy observation. Fourier transform infrared spectroscopy and X-ray diffraction analyses revealed that CEO successfully embedded into PVA-CS matrix through inter-molecular forces, thus improving the compact of CEO/PVA-CS. In simulate food systems (4 °C and 25 °C), the release patterns of CEO from CEO/PVA-CS fit well to Higuchi and Rigter-Peppas models, and could be explained by the Fickian diffusion mechanism. At refrigeration (4 °C), CEO/PVA-CS had 57.52 ± 3.33% inhibition rate on PPO, extracted from the cephalothorax of Litopenaeus vannamei, after 7 h of interaction. Moreover, CEO/PVA-CS effectively inhibited Lv-SSOs growth at 4 °C. Therefore, the electrospun film of CEO/PVA-CS should have potential application prospects in delaying melanosis and spoilage of refrigerated shrimp.

Germanium nanostructures by helium plasma irradiation

The effects of helium plasma irradiation, which has been widely studied on metals, on germanium have been experimentally investigated. The irradiation temperature ranges from 430 to 720 K, and the incident ion energy ranges from 30 to 100 eV. From the scanning electron microscope (SEM) observation, it was found that various morphological changes including pits, nanocones, nanopillars, and roughened surfaces occur. The spatial scale of the morphological change was analyzed by applying fast Fourier transform to SEM micrographs. Thermal desorption spectroscopy analysis suggests that He atoms implanted on Ge play major roles in forming roughened surfaces at a surface temperature higher than 500 K.

Properties of Fiber-Reinforced Geopolymer Mortar Using Coal Gangue and Aeolian Sand.

Geopolymers, as a novel cementitious material, exhibit typical brittle failure characteristics under stress. To mitigate this brittleness, fibers can be incorporated to enhance toughness. This study investigates the effects of varying polypropylene fiber (PPF) content and fiber length on the flowability, mechanical properties, and flexural toughness of coal gangue-based geopolymers. Microstructural changes and porosity variations within the Fiber-Reinforced Geopolymer Mortar(GMPF) matrix were observed using scanning electron microscope (SEM) and Low field NMR(LF-NMR) to elucidate the toughening mechanism of PPF-reinforced geopolymers. The introduction of fibers into the geopolymer matrix demonstrated an initial bridging effect in the viscous geopolymer slurry, with a 3.0 vol% fiber content reducing fluidity by 5.6%. Early mechanical properties of GMPF were enhanced with fiber addition; at 1.5 vol% fiber content and 15 mm length, the 3-day flexural and compressive strengths increased by 30.81% and 17.4%, respectively. Furthermore, polypropylene fibers significantly improved the matrix's flexural toughness, which showed an increasing trend with higher fiber content. At a 3.0 vol% fiber content, the flexural toughness index increased by 198.35%. The data indicated that a fiber length of 12 mm yielded the best toughening effect, with an 84.03% increase in the flexural toughness index. SEM observations revealed a strong interfacial bond between fibers and the matrix, with noticeable damage on the fiber surface due to frictional forces, and fiber pull-out being the predominant failure mode. Porosity testing results indicated that fiber incorporation substantially improved the internal pore structure of the matrix, reducing the median pore diameter of mesopores and converting mesopores to micropores. Additionally, the number of harmless and less harmful pores increased by 23.01%, while the number of more harmful pores decreased by 30.43%.

Mud Volcanoes and Adjacent Vegetation Adaptation in the Rembang Zone, Indonesia: An Approach for Mud Volcano Investigation

Abstract The Rembang Zone is a physiographic zone located in the northern part of Java, Indonesia. Rembang zone includes the areas from Rembang to Tuban and reaches the island of Madura. Ten mud volcanoes were identified, each with varying levels of eruptive intensity. Locals have reported that newly erupted mud materials can disrupt soil fertility in the surrounding areas, leading to vegetation death. Interestingly, we discovered several types of vegetation at mud volcano sites that have adapted, survived, and supported vegetation succession in the surrounding areas. Therefore, in this study, we investigated the vegetation around mud volcanoes in the Rembang Zone and its mud characteristics. We employed Sankey diagram analysis to explore the adapted plant taxa at mud volcano sites in the Rembang Zone. Additionally, we assessed the substrate using Scanning Electron Microscopy (SEM) and conducted geochemical analyses on fluid and non-condensable gas using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Gas Chromatography Mass Spectrometry (GC-MS). The results of this study reveal that there are at least 10 potential mud volcano sites in the Rembang Zone that could be inhabited by vegetation from the Poaceae family (20%), Asteraceae (18%), Cyperaceae (15%), Fabaceae (13%), Euphorbiaceae (9%), and other plant families (2%). These plants tend to adapt to the mud volcano substrate composed of Fe (0.00-0.35 mg/L), Ca (2.9-0.16%), Na (0.02-23.7%), and Cl (13-74%). This demonstrates that vegetation around mud volcanoes in the Rembang Zone can adapt to high-salinity conditions. SEM observations revealed a high smectite content associated with limestone rock. The mud volcanoes frequently emit gases such as N2 (2.3-73%), CH4 (0-8.8%), and CO2 (17-95%), indicating a tendency to produce substrates with nearly water-boiling temperatures (45-105°C). These findings serve as a reference for further understanding the presence of vegetation around mud volcanoes, particularly for identifying the presence of other mud volcanoes through remote sensing.

Effects of different pretreatments on Ti/RuO2-TiO2 anode

In this study, H2C2O4, H2SO4, HNO3, and HCl were used to etch the TA2 titanium matrix at the same concentration and temperature, and the effects of different acid etching methods on the properties of the titanium matrix and Ru-Ti electrode were investigated. The surface morphology of the titanium substrate and anode after acid etching was observed by scanning electron microscopy (SEM), while the electrochemical performance of the anode was determined by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and tafel plots. SEM observations showed that H2C2O4 had the best etching effect on the titanium substrate, as the scratches were uniform, and the surface cracks of the prepared anode reached 4–6 μm; Analysis of the CV curves revealed that the Ti/RuO2-TiO2 anode prepared by H2C2O4 etching had the highest surface charge capacity (172 mC) compared to the anodes prepared by other acid etchings, while the LSV curves showed that the Ti/RuO2-TiO2 anode after H2C2O4 etching had the lowest polarization potential (1.232 V). Tafel curve analysis revealed that the corrosion potential of the Ti anode prepared by H2C2O4 etching was 0.203 V, and the self-corrosion current density was −5.11 A cm−2, indicating that the corrosion resistance of the Ti anode prepared by H2C2O4 treatment is the weakest. X-ray photoelectron spectroscopy analysis showed that the electrode surface changed from Ru4+ to Ru3+ after corrosion, with the Ti2p spectra showing similar transition from Ti4+ to Ti3+.

Combining biochar with sediment in the treatment for the effectiveness of sulfate and heavy metal Pb reduction of acid mine drainage

The increasing mining activities have led to the problem of acid mine drainage (AMD) pollution. A method that combines biochar treatment as an adsorbent with wetland sediment treatment as a source of sulfate-reducing bacteria is used to address AMD effectively. This research aimed to determine the ability of biochar in combination with wetland sediment treatment to reduce sulfate and heavy metal content in acid mine drainage wastewater. This research was conducted on a laboratory scale in an AMD wastewater treatment reactor with the following treatments of biochar mixed with wetland sediment. Observations included sulfate content, pH, and heavy metal content. Scanning electron microscope (SEM) analysis was also performed on the biochar. SEM observations revealed the presence of small, dense, and irregularly shaped pores on the surface of the biochar. The results on day 30 showed that biochar mixed with wetland sediment was able to reduce sulfate concentration by 74.19% and reduced Pb by 73.79%, compared with treatment sediment only to 64.81% sulfate concentration and reduced Pb by 53.85%, treatment biochar only had reduced sulfate of 46.90% and reduced Pb by 58.67% and control 1.79% sulfate concentration and reduced Pb by 1.87%.

Surface Insights of Mesoporous Fragile Organic Materials Under Ultra‐Low‐Voltage Directed by Gemini Column

AbstractMesoporous materials find widespread applications due to their high specific surface area, contributing to enhanced performance. Scanning electron microscopy (SEM) observation of mesoporous materials provides valuable insights into their mesostructures. However, direct observation of the outermost surfaces, which often dictate material properties, remains challenging, especially for highly insulating and fragile compounds. In this study, utilizing SEM observation with ultra‐low‐voltage acceleration directed by Gemini column is proposed to achieve direct surface imaging of mesoporous organic materials with highly insulating and fragile characteristics. By observing mesostructured polymers obtained through a soft‐templating method without washing, stuffed pores are identified allowing the differentiation of micelle templates and polymer walls. Moreover, leveraging SEM measurements, a polymerization mechanism is proposed for dopamine on the polymer micelles adhered to the graphene oxide nanosheets. These findings demonstrate the potential of SEM measurements with ultra‐low accelerating voltage in facilitating surface observations of polymer‐derived nanomaterials characterized by high insulating properties and a fragile framework.

Mechanical Properties of Additively Manufactured Polymeric Materials-PLA and PETG-For Biomechanical Applications.

The study presented herein concerns the mechanical properties of two common polymers for potential biomedical applications, PLA and PETG, processed through fused filament fabrication (FFF)-Material Extrusion (ME). For the uniaxial tension tests carried out, two printing orientations-XY (Horizontal, H) and YZ (Vertical, V)-were considered according to the general principles for part positioning, coordinates, and orientation typically used in additive manufacturing (AM). In addition, six specimens were tested for each printing orientation and material, providing insights into mechanical properties such as Tensile Strength, Young's Modulus, and Ultimate Strain, suggesting the materials' potential for biomedical applications. The experimental results were then compared with correspondent mechanical properties obtained from the literature for other polymers like ASA, PC, PP, ULTEM 9085, Copolyester, and Nylon. Thereafter, fatigue resistance curves (S-N curves) for PLA and PETG, printed along 45°, were determined at room temperature for a load ratio, R, of 0.2. Scanning electron microscope observations revealed fibre arrangements, compression/adhesion between layers, and fracture zones, shedding light on the failure mechanisms involved in the fatigue crack propagation of such materials and giving design reference values for future applications. In addition, fractographic analyses of the fatigue fracture surfaces were carried out, as well as X-ray Computed Tomography (XCT) and Thermogravimetric (TGA)/Differential Scanning Calorimetric (DSC) tests.

Pseudogomphonema lukinicum sp. nov. (Bacillariophyceae), a new endophytic diatom found inside multicellular red algae from the Northwest Pacific

Abstract In our collections from the Northwest Pacific waters, we found several specimens of the red algae Lukinia dissecta and Callophyllis perestenkoae with darker spots on their thalli, which contained an unusual pennate diatom. A detailed morphological analysis based on light and scanning electron microscopy observations made it possible to describe a new species of endophytic diatom, Pseudogomphonema lukinicum sp. nov. Stonik et Skriptsova. The new species has some morphological features typical of the genus, such as the heteropolarity of the valves, the presence of pseudosepta and small apical chambers at both poles of the valves, and nonporous girdle bands. Pseudogomphonema lukinicum has been described and distinguished from the other species in the genus on the basis of a combination of morphological traits, including relatively small cell dimensions, a slightly asymmetrical valve to the transapical axis, with obtusely rounded headpole and narrower footpole, the large asymmetrical central area, and the presence of apical chambers at both poles. Pseudogomphonema lukinicum is the second representative of Pseudogomphonema known to be living endophytically. The data on the species composition of endophytic diatoms in marine macroalgae, their habitats, and host organisms reported in the literature to date are summarized.

Revealing the Mechanism Underlying 3D-AFM Imaging of Suspended Structures by Experiments and Simulations.

The invention of 3D atomic force microscopy (3D-AFM) has enabled visualizing subnanoscale 3D hydration structures. Meanwhile, its applications to imaging flexible molecular chains have started to be experimentally explored. However, the validity and principle of such imaging have yet to be clarified by comparing experiments and simulations or cross-observations with an alternative technique. Such studies are impeded by the lack of an appropriate model. Here, this difficulty is overcome by fabricating 3D carbon nanotube (CNT) structures flexible enough for 3D-AFM, large enough for scanning electron microscopy (SEM), and simple enough for simulations. SEM and 3D-AFM observations of the same model provide unambiguous evidence to support the possibility of imaging overlapped nanostructures, such as suspended CNT and underlying platinum (Pt) nanodots. Langevin dynamics simulations of such 3D-AFM imaging clarify the imaging mechanism, where the flexible CNT is laterally displaced to allow the AFM probe access to the underlying structures. These results consistently show that 3D-AFM images are affected by the friction between the CNT and AFM nanoprobe, yet it can be significantly suppressed by oscillating the cantilever. This study reinforces the theoretical basis of 3D-AFM for imaging various 3D self-organizing systems in diverse fields, from life sciences to interface sciences.

Hybrid Steel-Polyethylene Fiber-Reinforced Iron Ore Tailing Concrete: Mechanical, Sulfate Freeze–Thaw Resistance, and Microscopic Characteristics

This study examines the effects of iron ore tailing (IOT) replacement ratios and the hybridization of steel fiber (SF) and polyethylene (PE) fiber (PF) on the mechanical, sulfate freeze–thaw (F–T) resistance, and microscopic characteristics of IOT concrete. The mechanical properties of specimens including compressive strength (fcu) and splitting tensile strength (fsts) were evaluated. Sulfate F–T cycle indices of specimens including surface damage, fcu loss, relative dynamic elastic modulus (RDEM), and mass loss are examined. Meanwhile, microscopic characteristics are analyzed using industrial computer technology (CT) and scanning electron microscopy (SEM). Results indicated that IOT replacement ratios below 40% positively influenced mechanical properties and sulfate F–T resistance, whereas ratios exceeding 40% exhibited adverse effects. Incorporating hybrid SF and PF further enhanced the mechanical properties and sulfate F–T resistance of IOT concrete. The IOT concrete containing 1.5% SF and 0.6% PF (designated T40S1.5P0.6) demonstrates significantly improved mechanical properties and sulfate F–T resistance. A set of parameters was proposed to predict the fsts. The Weibull damage model, capable of quantitatively reflecting the F–T damage of IOT concrete, was established. The pore structure of IOT concrete gradually deteriorates with increasing sulfate F–T cycles. The pore characteristics of T40S1.5P0.6 were superior. This was further validated through SEM observations.

Antifungal Activity and Possible Mechanism of Streptomyces nojiriensis 9-13 Against Mycogone sp., Causing Wet Bubble Disease on Agaricus bisporus.

Wet bubble disease (WBD) in Agaricus bisporus caused by Mycogone species imposes a substantial economic loss to mushroom production in China. Currently, fungicide application is the main method to control WBD. However, excessive use of fungicides is challenged by the appearance of resistance and food safety. Therefore, it is necessary to explore safe and efficient strategies to control WBD. Strain 9-13, isolated from the rhizosphere soil of Taxus chinensis, showed strong inhibitory activity against three Mycogone species. According to morphological and biochemical characteristics and multilocus phylogenetic analysis, the strain was identified as Streptomyces nojiriensis. In addition, strain 9-13 extracts significantly inhibited mycelial growth and spore germination of M. perniciosa, M. rosea, and M. xinjiangensis in vitro. Strain 9-13 and its extracts also exhibited broad-spectrum antifungal activities against 12 selected plant pathogenic fungi. Scanning electron microscopic observations showed that the extracts destroyed mycelial structure, inducing mycelia to twist and shrink. Moreover, transmission electron microscopy revealed that the extracts resulted in severe plasmolysis, rupture of the cell membrane, and a decrease in cell inclusions, and the cell wall had a rough and uneven surface. Notably, the extracts obviously reduced disease severity and incidence of WBD by from 83.85 to 87.32% in fruiting bodies and 77.36% in mushroom beds and maintained fruiting time and color on harvested mushrooms. Collectively, these results clearly indicate that S. nojiriensis 9-13 is a promising biocontrol agent to control WBD on A. bisporus.