Electron Microscopy Research Articles

Study on the Coarsening Behavior of Interphase Precipitates and Random Precipitates in Steel Under the High-Temperature Environment of Fire

In the domain of fire-resistant steels, the characteristics of precipitates significantly influence material properties. This study developed a novel heat treatment protocol to concurrently achieve both interphase precipitation and random precipitation. Samples were subjected to isothermal treatments at various temperatures and durations, while techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to thoroughly analyze the coarsening behavior of the two types of precipitate and reveal their thermal stability differences. The results show that the growth and coarsening rates of interphase precipitates are substantially lower than random precipitates. Coarsening kinetics analysis reveals that the radius of random precipitates follows a 1/3 power law with time at 600 °C and 650 °C, whereas the radius of interphase precipitates adheres to a 1/6 power law at 600 °C and a 1/5 power law at 650 °C. Furthermore, interphase precipitation demonstrates excellent size uniformity, which hinders the formation of a concentration gradient, thereby reducing the coarsening rate and enhancing thermal stability. After prolonged tempering treatment, interphase precipitation maintains a higher strengthening contribution than random precipitation. This study provides novel insights and theoretical foundations for the design and development of fire-resistant steels.

Comparative In Vitro Study of Sol–Gel-Derived Bioactive Glasses Incorporated into Dentin Adhesives: Effects on Remineralization and Mechanical Properties of Dentin

To overcome limitations of dentin bonding due to collagen degradation at a bonded interface, incorporating bioactive glass (BAG) into dentin adhesives has been proposed to enhance remineralization and improve bonding durability. This study evaluated sol–gel-derived BAGs (BAG79, BAG87, BAG91, and BAG79F) and conventional melt-quenched BAG (BAG45) incorporated into dentin adhesive to assess their remineralization and mechanical properties. The BAGs were characterized by using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy for surface morphology. The surface area was measured by the Brunauer–Emmett–Teller method. X-ray diffraction (XRD) analysis was performed to determine the crystalline structure of the BAGs. Adhesive surface analysis was performed after approximating each experimental dentin adhesive and demineralized dentin by using FE-SEM. The elastic modulus of the treated dentin was measured after BAG-containing dentin adhesive application. The sol–gel-derived BAGs exhibited larger surface areas (by 400–600 times) than conventional BAG, with BAG87 displaying the largest surface area. XRD analysis indicated more pronounced and rapid formation of hydroxyapatite in the sol–gel BAGs. Dentin with BAG87-containing adhesive exhibited the highest elastic modulus. The incorporation of sol–gel-derived BAGs, especially BAG87, into dentin adhesives enhances the remineralization and mechanical properties of adhesive–dentin interfaces.

High‐voltage electron microscopy analyses for crack‐tip dislocations and their shielding effect on fracture toughness in MgO and Si crystals

AbstractIn this study, characteristics of dislocation structures around a crack‐tip in both crystals of MgO and Si were investigated using high‐voltage electron microscopy (HVEM). The interaction between a crack and dislocations was analyzed to discuss the effect of crack‐tip plasticity on fracture toughness. The present paper first demonstrates a dislocation configuration around a crack‐tip in a MgO thin crystal, where the plastic zone called 45°‐shear type is dominant under the plane stress condition. Then, the slip systems necessary for brittle‐to‐ductile transition in ionic crystals with the rock‐salt structure are discussed based on the temperature dependence of stress‐strain relationships and the aspect of crack front observed in NaCl crystals. Second, crack‐tip dislocations near the surface of bulk Si crystals are exhibited based on the 3D analyses using HVEM tomography. We focus on a newfound plastic zone being perpendicular to the crack plane, which is different from either 45°‐shear type or the hinge type generally well‐known. The dislocation loops observed in this plastic zone fundamentally have a crack‐tip shielding effect to increase fracture toughness. Still, in addition, they contribute to activating crack‐tip dislocations by their localized antishielding field. These analyses reveal a fundamental toughening mechanism for crystalline materials.

Fabrication of MoS2@Fe3O4 Magnetic Catalysts with Photo-Fenton Reaction for Enhancing Tetracycline Degradation

Tetracycline (TCs) is widely used in the treatment of human and animal infectious disease. TCs gives rise to a growing threat to the human health and environment protection due to its overuse. Therefore, it is important to remove TCs contaminants from waste effluents. In this work, MoS2@Fe3O4 catalytic material was fabricated by the simple hydrothermal method, which was applied in the photo-Fenton system to degrade TCs. The crystal structure, surface morphology, elemental composition, chemical state, electrochemical properties, and separability of MoS2@Fe3O4 catalytic materials were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), conventional and high-resolution transmission electron microscopy (TEM/HRTEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and vibrating sample magnetometry (VSM). Furthermore, MoS2@Fe3O4 could degrade 98.6% of TCs within 60 min under the optimum reaction conditions (the catalyst dosage of 3 g/L, H2O2 concentration of 5 mmol/L, the initial TCs concentration of 50 mg/L, and the initial pH of 5), which was a significant increase compared with pure Fe3O4. MoS2 can accelerate the Fe3+/Fe2+ cycle through electron transfer from Mo4+ to Fe3+, resulting in the improvement in the degradation efficiency of TCs. The quenching and electron paramagnetic resonance (EPR) results showed that OH• and photogenic hole h+ was the main active species in the photo-Fenton system. What is more, MoS2@Fe3O4 catalytic materials had remarkable stability and reusability, and can be handily regained via magnetic separation technology in a real scenario.

Nesfatin-1 Neurons in the Ventral Premammillary Nucleus Integrate Metabolic and Reproductive Signals in Male Rats

The ability to reproduce depends on metabolic status. In rodents, the ventral premammillary nucleus (PMv) integrates metabolic and reproductive signals. While leptin (adiposity-related) signaling in the PMv is critical for female fertility, male reproductive functions are strongly influenced by glucose homeostasis. The anorexigenic peptide nesfatin-1 is a leptin-independent central regulator of blood glucose. Therefore, its integrative role in male rats can be assumed. To investigate this, we mapped the distribution of nesfatin-1 mRNA- and protein-producing cells in the PMv during postnatal development via in situ hybridization and immunohistochemistry, respectively. Fos-nesfatin-1, double immunostaining was used to determine the combined effect of heterosexual pheromone challenge and insulin-induced hypoglycemia on neuronal activation in adults. We found that ~75% of the pheromone-activated neurons were nesfatin-1 cells. Hypoglycemia reduced pheromone-induced cell activation, particularly in nesfatin-1 neurons. Immuno-electron microscopy revealed innervation of PMv nesfatin-1 neurons by urocortin3-immunoreactive terminals, reportedly originating from the medial amygdala. Nesfatin-1 immunopositive neurons expressed GPR10 mRNA, a receptor associated with metabolic signaling, but did not respond with accumulation of phosphorylated STAT3 immunopositivity, a marker of leptin receptor signaling, in response to intracerebroventricular leptin treatment. Our results suggest that PMv nesfatin-1 neurons are primarily responsible for integrating reproductive and metabolic signaling in male rats.

Mechanism and Characterization of Bicomponent-Filler-Reinforced Natural Rubber Latex Composites: Experiment and Molecular Dynamics (MD)

The incorporation of reinforcing fillers into natural rubber latex (NR) to achieve superior elasticity and mechanical properties has been widely applied across various fields. However, the tendency of reinforcing fillers to agglomerate within NR limits their potential applications. In this study, multi-walled carbon nanotube (MWCNT)–silica (SiO2)/NR composites were prepared using a solution blending method, aiming to enhance the performance of NR composites through the synergistic effects of dual-component fillers. The mechanical properties, dispersion behavior, and Payne effect of three types of composites—SiO2/NR (SNR), MWCNT/NR (MNR), and MWCNT-SiO2/NR (MSNR)—were investigated. In addition, the mean square displacement (MSD), fractional free volume (FFV), and binding energy of the three composites were simulated using molecular dynamics (MD) models. The results showed that the addition of a two-component filler increased the tensile strength, elongation at break, and Young’s modulus of NR composites by 56.4%, 72.41%, and 34.44%, respectively. The Payne effect of MSNR was reduced by 4.5% compared to MNR and SNR. In addition, the MD simulation results showed that the MSD and FFV of MSNR were reduced by 21% and 17.44%, respectively, and the binding energy was increased by 69 times, which was in agreement with the experimental results. The underlying mechanisms between the dual-component fillers were elucidated through dynamic mechanical analysis (DMA), a rubber process analyzer (RPA), and field emission scanning electron microscopy (SEM). This study provides an effective reference for broadening the application fields of NR.

Biomechanical and biodegradation performance of CSA-CSF reinforced cementitious composites: A bio-inspired approach

This study investigates the mechanical, biodegradation, and microstructural performance of cementitious composites reinforced with Corn Straw Ash (CSA) and Corn Straw Fiber (CSF) for applications in bio-inspired materials and sustainable engineering. CSA, a pozzolanic material, enhances matrix densification, while CSF provides crack-bridging and toughness improvement. Dynamic mechanical testing under cyclic loading demonstrated that CSA-CSF composites exhibit superior fatigue resistance, retaining 85% of their initial compressive strength after 1000 cycles. Biodegradation studies in simulated body fluid (SBF) and acidic environments revealed that the composites maintain 75% compressive strength in SBF over 28 days, highlighting their potential for bioactive scaffolds. Scanning electron microscopy (SEM) and quantitative porosity analysis showed that CSA-derived Calcium Silicate Hydrate (C-S-H) gel effectively filled voids, while CSF enhanced fiber-matrix bonding, mimicking the hierarchical structure of biological systems. The results emphasize the dual benefits of CSA-CSF composites in dynamic environments and their alignment with sustainable and bio-inspired design principles. This research provides insights into the development of materials for biomechanical applications, including tissue engineering scaffolds and earthquake-resistant structures.

The Effect of Alumina-Rich Spinel Exsolution on the Mechanical Property of Calcium Aluminate Cement-Bonded Corundum Castables

This study investigates the effect of the exsolution behavior of alumina-rich spinel on the formation and distribution of CA6 (CaAl12O19) in corundum castables bonded with calcium aluminate cement. In this study, alumina-rich spinel is substituted for tabular corundum in the same proportions and grain size. The matrices after curing were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The phase composition and microstructure of the matrices containing alumina-rich spinel were analyzed after firing at 1600 °C. These results showed that the addition of alumina-rich spinel significantly improved the mechanical strength of the castables. This improvement was attributed to the alumina produced by spinel exsolution during firing at 1600 °C, which reacted in situ with CA2 (CaAl4O7) to form CA6. CA6 connects the different particles and forms an interspersed interlocking structure within the spinel. The CA6-MA interspersed interlocking structure replaces part of the CA6-Al2O3 structure and significantly improves the mechanical strength of the castables.

In situ alloying of AlCuSi using dual-wire-directed energy deposition with plasma

Abstract The current research explores additive manufacturing of a multi-phase material using dual-wire plasma-directed energy deposition technology. With this approach, new materials can be designed and tested easily on the basis of commercially available consumables. In this work, AlSi5 and CuAl8 solid wire consumables are used to produce a specific AlCuSi alloy by controlling the welding parameters and the wire feed ratio. Initial experimentation results in an alloy with 85.7 at.% aluminum, 8.4 at.% copper, 2.7 at.% silicon, and 3.2 at.% magnesium, but with some instabilities during the process. The presence of magnesium in the chemical composition could be related to plasma interaction with the substrate during the welding process. After optimizing the process parameters, the chemical composition obtained is about 76.3 at.% aluminum, 19.9 at.% copper, and 3.8 at.% silicon. Using microstructural analysis via light and scanning electron microscopy, defects such as pores and inadequately melted Cu wire material are observed in all materials produced. Although the optimization of the melting process improved the microstructure, it also increased the copper content, which in turn exerts a significant influence on the mechanical properties. Mechanical testing indicates significant embrittlement. The results underscore that the microstructure is heavily influenced by the chemical composition. Microstructural changes caused by the higher copper content, i.e., in particular the increase of the volume fraction of brittle intermetallic phases such as θ-Al2Cu, result in severe embrittlement of the obtained materials, denoted by higher hardness and reduced toughness. We conclude that the use of dual-wire plasma additive manufacturing can develop new materials by in situ alloying.

Confocal Laser Scanning Microscopy as a Method for Identifying Variation in Puparial Morphology and Establishing Characters for Taxonomic Determination

Calliphoridae, or blow flies, are of much ecological and practical importance given their roles in decompositional ecology, medical and veterinary myiasis, and forensic entomology. As ephemeral and rapidly developing species, adults are frequently not present for identification, but puparia (the remaining outer integument of the third instar larvae) are frequently found. These heavily sclerotized remains are stable in the environment but they are of a conservative character. Historically, scanning electron microscopy (SEM) has been used for characterization, a technique which is not only time-consuming but also often expensive, effectively making large numbers of specimens impossible to quantify. As an alternative, confocal laser scanning laser microscopy (CSLM) was tested for utility in providing superior data over SEM. Furthermore, due to the use of intrinsic autofluorescence for imagining, CSLM is significantly more rapid than SEM, requiring no preparation for imaging. Three channels of excitation and emission spectra provided not only image data from the pupal wall but also from the hydrocarbons found upon the puparia. The excitation wavelengths were 404.7, 488, and 640.5 nm, and the emissions were 425–475, 500–550, and 663–738 nm. For ten species of calliphorids, CSLM was used to image puparia. Not only did this provide characters for species identification but it also allowed for the examination of hundreds of specimens.

Nanoscale Pore Evolution of Terrestrial Shale with Thermal Maturation Level Increase Induced by Hydrous Pyrolysis

A series of terrestrial shale samples with different thermal maturities were subjected to hydrous artificial pyrolysis to study the evolution of terrestrial shale pores. The original shale was obtained from the terrestrial interval of a core sample, the total organic carbon (TOC) content was 8.34 wt%, and the vitrinite reflectance (Ro) was 5.31%. The original shale core was cut into eight parts, which were heated at temperatures of 300, 350, 400, 420, 450, 500, 550, and 600 °C to obtain samples with different thermal maturities. The pore size distribution (PSD), pore volume (PV), specific surface area (SSA), and pore types were investigated via CO2 and N2 adsorption tests and field emission scanning electron microscopy (FE-SEM). Many organic matter (OM) pores and mineral pores were observed via FE-SEM with increasing thermal maturity. The total PV and SSA increased until the sample reached 500 °C and then decreased, and the mesopore volume followed this trend. The micropore volume first decreased, increased until the sample reached 500 °C, and then decreased; the macropore volume increased to a peak in the sample pyrolyzed at 420 °C and then remained stable. Pores with sizes ranging from 10 to 30 nm were the predominant contributors to the shale pore volume. The SSA was affected by pores with diameters less than 20 nm, which accounted for approximately 54% of the SSA. The rate of OM conversion influenced pore creation.

Behavior of YSZ (High Y2O3 Content) Layer on Inconel to Electro-Chemical Corrosion

The high yttria content of a stabilized zirconia (YSZ) (38 wt% Y2O3) coating was deposited by atmospheric plasma spraying (APS) from Metco 207 powders on an Inconel 718 (Ni-based superalloy) substrate. As a metal coating connection, a layer of cermet powder (Ni-20% Al—410NS) was used before the ceramic layer deposition. The electro-chemical corrosion resistance of these materials was tested using Inconel cylinders with a diameter of 10 mm and a thickness of 1 mm, with and without the ceramic layer. Linear and cyclic measurements were obtained in H2SO4 electrolyte media at pH = 2. Electro-impedance spectroscopy (EIS) experiments were performed on the sample covered with the ceramic layer to evaluate the interface behavior. Scanning electron microscopy (SEM), along with equipment to determine chemical composition, and an energy dispersive spectrometry (EDS) detector were used to characterize the material surface before and after corrosion tests. It was observed that the corrosion resistance of Inconel was influenced by the bonding layer and the ceramic coating.

Synthesis of P(AM/AA/SSS/DMAAC-16) and Studying Its Performance as a Fracturing Thickener in Oilfields

In order to solve the problems of long dissolution and preparation time, cumbersome preparation, and easy moisture absorption and deterioration during storage or transportation, acrylamide (AM), acrylic acid (AA), sodium p-styrene sulfonate (SSS), and cetyl dimethylallyl ammonium chloride (DMAAC-16) were selected as raw materials, and the emulsion thickener P(AM/AA/SSS), which can be instantly dissolved in water and rapidly thickened, was prepared by the reversed-phase emulsion polymerization method. DMAAC-16, the influence of emulsifier dosage, oil–water ratio, monomer molar ratio, monomer dosage, aqueous pH, initiator dosage, reaction temperature, reaction time, and other factors on the experiment was explored by a single-factor experiment, and the optimal process was determined as follows: the oil–water volume ratio was 0.4, the emulsifier dosage was 7% of the oil phase mass, the initiator dosage was 0.03% of the total mass of the reaction system, the reaction time was 4 h, the reaction temperature was 50 °C, the aqueous pH was 6.5, and the monomer dosage was 30% of the total mass of the reaction system (monomeric molar ratio n(AM):n(AA):n(SSS):n(DMAAC-16) = 79.2:20:0.5:0.3). X-ray diffraction analysis (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy analysis were carried out on the polymerization products. At the same time, a series of performance test experiments such as thickening performance, temperature and shear resistance, salt resistance, sand suspension performance, core damage performance, and fracturing fluid flowback fluid reuse were carried out to evaluate the comprehensive effect and efficiency of the synthetic products, and the results show that the P(AM/AA/SSS/DMAAC-16) polymer had excellent solubility and excellent properties such as temperature and shear resistance.

Genetically Controlled Iron Oxide Biomineralization in Encapsulin Nanocompartments for Magnetic Manipulation of a Mammalian Cell Line

AbstractMagnetic nanoparticles have proven invaluable for biomechanical investigations due to their ability to exert localized forces. However, cellular delivery of exogenous magnetic agents often results in endosomal entrapment, thereby limiting their utility for manipulating subcellular structures. This study characterizes and exploits fully genetically controlled biomineralization of iron‐oxide cores inside encapsulin nanocompartments to enable magnetic‐activated cell sorting (MACS) and magnetic cell manipulation. The fraction of MACS‐retained cells showed substantial overexpression of encapsulins and exhibited both para‐ and ferrimagnetic responses with magnetic moments of 10−15 A m2 per cell, comparable to standard exogenous labels for MACS. Electron microscopy revealed that MACS‐retained cells contained densely packed agglomerates of ≈30 nm iron oxide cores consisting of ultrafine quasicrystalline ordered nuclei within an amorphous matrix of iron, oxygen, and phosphorus. Scanning transmission X‐ray microscopy, X‐ray absorption spectroscopy, and Raman microspectroscopy confirmed that the iron‐oxide species are consistent with ferric oxide (Fe2O3). In addition, the encapsulin‐overexpressing MACS‐retained cells can be manipulated by a magnetic needle and regrown in patterns determined by magnetic gradients. This study demonstrates that the formation of quasicrystalline iron oxide with mixed para/ferrimagnetic behavior in the cytosol of mammalian cells enables magnetic manipulation without the delivery of exogenous agents.

Spectroscopic and Morphological Examination of Co0.9R0.1MoO4 (R = Ho, Yb, Gd) Obtained by Glycine Nitrate Procedure

The glycine nitrate procedure (GNP) is a method that proved to be the easiest and most effective method for controlling the composition and morphology during the synthesis of Co0.9R0.1MoO4 (R = Ho, Yb, Gd). This method of the combustion process achieves control of stoichiometry, homogeneity, and purity. Metal nitrates and glycine were mixed in the appropriate stoichiometric ratios to produce Co0.9R0.1MoO4 (R = Ho, Yb, Gd). The samples obtained by the mentioned method were further subjected to different characterization methods such as differential thermal analyses (DTA), X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), spectroscopy, field emission scanning electron microscopy (FESEM), and nitrogen adsorption method. A high level of anisotropy of the shape and size of particles in the form of agglomerates was found. Also, there are noticeable differences in the microstructure and plate crystals. The color of the synthesized sample changes from darker to lighter shades after thermal treatments. There are pronounced changes in the dominant wavelength (nm) and color purity between the initial sample and the sample after heating (1100 °C) due to the concentration of Co.

Research on the Composition and Casting Technology of Bronze Arrowheads Unearthed from the Ruins of the Imperial City of the Minyue Kingdom

The ruins of the Imperial City of the Minyue Kingdom were an important site of the Minyue Kingdom during the Han Dynasty. Characteristic bronze arrowheads unearthed from the East Gate, with their exquisite craftsmanship, provide important physical evidence for studying ancient bronze casting technology and the military activities of that time. However, there is still a lack of systematic research on the alloy composition, casting process, and chemical stability of these arrowheads in long-term burial environments. The bronze arrowheads that were found in the East Gate warehouse are the subject of this study. Metallographic analysis, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) were used to carefully examine their composition and microstructure, as well as the casting process characteristics. The findings reveal the following: (1) The East Gate bronze arrowheads primarily consist of copper–tin binary alloys, and certain samples exhibit a lead (Pb) content of up to 11.19%, potentially due to element addition during casting or element migration in the burial environment. (2) The metallographic structure shows that the sample matrix has a typical α-dendrite structure, indicating that a high-temperature casting process was used, and then a certain surface treatment was performed to enhance corrosion resistance. (3) Under a scanning electron microscope, it was observed that a three-layer structure was formed on the surface of the arrowhead, including a fully mineralized layer, an intermediate transition layer, and the original core tissue. (4) The detection of molybdenum (Mo) in some samples suggests a close relationship between the complexity of the buried soil environment and human activities. (5) By comparing the microstructure and corrosion degree of the longitudinal section and the cross-section, it was found that the longitudinal section has a stronger corrosion resistance due to its denser structure. Comprehensive analysis shows that the technical details of the bronze arrowheads unearthed from the Minyue Imperial City in terms of material selection, casting process, and later use reflect the outstanding achievements of the Minyue Kingdom in the field of bronze manufacturing in the Han Dynasty.

Study of the influence of carbon nanotubes, graphene, and hybrid buckypaper on the mechanical behavior of PAEK/carbon fiber composites

AbstractCarbon fiber‐reinforced thermoplastic composites are widely used in the aeronautical industry due to their high mechanical properties and low specific weight. Within the select group of thermoplastic matrices, poly (aryl ether ketone) (PAEK) stands out as a semicrystalline material with high glass transition and melting temperatures. This work aims to evaluate how buckypaper (BP) influences the mechanical properties of the composite PAEK/CF. For this, three types of BPs were made using vacuum filtration. The first one is with carbon nanotubes (CNT), the second is with graphene (GR), and the third is a mix of CNT and GR. The influence of BPs in mechanical behavior was performed by an interlaminar short beam test (ILSS), a compression shear test (CST), and an impulse excitation of vibration. Finally, the presence of BP reduced the mechanical properties of the material due to the low adhesion between matrix and BP. In the ILSS test, it was noted a reduction in interlaminar shear of 16% for CNT BP, 20% for GR BP and 28% for hybrid BP. In the CST, a reduction of 32% for CNT BP, 39% for GR BP and 13% for hybrid BP was observed. On the other hand, the composite with hybrid BP presents a greater increase in Young's Modulus, representing a gain of 13%.Highlights The vacuum filtration process used to produce BPs was determined. Morphology evaluation of BPs through scanning electron microscopy. Influence of BPs on the mechanical properties of composites. Effect of nanoparticles on the adhesion between matrix and BPs.

Preparation and Gas-Sensitive Properties of SnO2@Bi2O3 Core-Shell Heterojunction Structure

The SnO2@Bi2O3 core-shell heterojunction structure was designed and synthesized via a hydrothermal method, and the structure and morphology of the synthesized samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Based on the conclusions from XRD and SEM, it can be observed that as the hydrothermal temperature increases, the content of Bi2O3 coated on the surface of SnO2 spheres gradually increases, and the diameter of Bi2O3 nanoparticles also increases. At a hydrothermal temperature of 160 °C, the SnO2 spheres are fully coated with Bi2O3 nanoparticles. This paper investigated the gas-sensitive performance of the SnO2@Bi2O3 sensor towards ethanol gas. Gas sensitivity tests at the optimal operating temperature of 300 °C showed that the composite prepared at 160 °C achieved a response value of 19.7 for 100 ppm ethanol. Additionally, the composite exhibited excellent response to 100 ppm ethanol, with a response time of only 4 s, as well as good repeatability. The excellent gas-sensitive performance of the SnO2@Bi2O3 core-shell heterojunction towards ethanol gas is attributed to its p-n heterojunction material properties. Its successful preparation contributes to the realization of high-performance heterostructure ethanol gas sensors.

Advancing the Taxonomy of the Diatom Pseudo-nitzschia Through an Integrative Study Conducted in the Central and Southeastern Adriatic Sea

The marine diatom genus Pseudo-nitzschia comprises cosmopolitan phytoplankton species commonly present in the Adriatic Sea. Species within the genus Pseudo-nitzschia have been of significant concern because they produce domoic acid (DA), which can cause amnesic shellfish poisoning (ASP). In this study, we identified Pseudo-nitzschia species along the Central and Southeastern Adriatic Sea, where monthly sampling carried out from February 2022 to February 2024 allowed for comprehensive species documentation. Pseudo-nitzschia species cell cultures isolated from the study areas were morphologically and molecularly analysed. Morphological analyses were performed using a scanning electron microscope (FE-SEM/STEM), while molecular analyses were conducted, targeting the ITS1-5.8S-ITS2, LSU, and rbcL regions, to confirm species identity. This integrative approach led to the identification of eight species: Pseudo-nitzschia allochrona, Pseudo-nitzschia calliantha, Pseudo-nitzschia delicatissima, Pseudo-nitzschia fraudulenta, Pseudo-nitzschia mannii, Pseudo-nitzschia multistriata, Pseudo-nitzschia pseudodelicatissima, and Pseudo-nitzschia subfraudulenta. Our findings underscore the value of a combined approach for reliable species identification and contribute to the development of genetic sequence databases that support the advancement of next-generation methods such as metabarcoding. This research emphasises the importance of combined morphological and molecular methods for the differentiation of the cryptic and pseudo-cryptic Pseudo-nitzschia species.

Silver and Titanium Oxides Coated on g-C3N4 Nanocomposite for Photocatalytic Degradation of Mixture of Brilliant Green-Congo Red Dyes and Ciprofloxacin Antibiotic Under Visible Light Irradiation

Silver and titanium oxides coated graphitic carbon nitride (Ag2O/TiO2/g-C3N4) nanocomposite was created by a single-step thermal polymerization. The Fourier Transform infrared (FT-IR), UV-visible absorption spectroscopy (UV-vis), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) methods, thermal gravimetric analysis (TGA), photoluminescence (PL), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were within the numerous techniques used to characterize this nanocomposite. Both the photoluminescence (PL) spectrum and the Tauc plot indicated that the Ag2O/TiO2/g-C3N4 nanocomposite had a lower electron-hole pair recombination rate and lower band gap energy. The coating of Ag2O and TiO2 on g-C3N4 was verified by TEM. The Ag2O/TiO2/g-C3N4 nanocomposite was used in the photocatalytic degradation of a Brilliant green (BG)-Congo red (CR) dye combination and ciprofloxacin (CIP) antibiotic under visible light irradiation. According to the research, under visible light irradiation, the Ag2O/TiO2/g-C3N4 nanocomposite photocatalytic activity simultaneously degraded a mixture of BG-CR dyes, with BG (93%) and CR (85%) degrading percentages in 70 min and CIP (82%) degrading in 120 min. Superoxide and hydroxyl radicals were primarily responsible for the degradation of BG and CR dyes under visible light irradiation, whereas holes and hydroxyl radicals were investigated as important oxidative species in the photocatalytic degradation of CIP utilizing the Ag2O/TiO2/g-C3N4 nanocomposite.Graphical