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Ag-induced crystallization and layer exchange (AgILE) in a stack of amorphous Si/Ag/quartz substrate has been investigated using optical microscopy, scanning electron microscopy, transmission electron microscopy (TEM), scanning TEM-high angle annular dark field (STEM-HAADF) imaging, and electron tomography, covering length scales from a few tens of micrometers to a few tens of nanometers. The size of Ag grains in the underlying as-deposited Ag film varied from ∼10 to 500 nm. The following processes could be discerned using in situ heating of plan-view samples at 500 °C in STEM: (i) AgILE propagation preferentially along regions of small Ag grains, (ii) formation of pushed-up Ag in the vicinity of AgILE reaction cells, (iii) migration and agglomeration of pushed-up Ag on small and large Ag grains, which tend to inhibit AgILE and promote dendricity, and (iv) dispersion of pushed-up Ag, which tend to reduce dendricity. The resulting dendricity was largely confined to the peripheral regions of the impinging reaction cells and decreased with annealing time. In contrast, dendricity due to AgILE and crystallization at 550 °C is stable and extends right from the center to the periphery of the reaction cells. The microscopic mechanism of AgILE and, in particular, the effect of annealing temperature is investigated. The results are discussed in the light of existing literature and compared with Al-induced layer exchange. Annealing at temperature equal to or slightly less than 500 °C is found to be necessary in the case of AgILE to avoid dendricity and to obtain a continuous Si layer with large Si grains. [ABSTRACT FROM AUTHOR]

Bragg interferometry (BI) is an imaging technique based on four-dimensional scanning transmission electron microscopy (4D-STEM) wherein the intensities of select overlapping Bragg disks are fit or more qualitatively analyzed in the context of simple trigonometric equations to determine local stacking order. In 4D-STEM based approaches, the collection of full diffraction patterns at each real-space position of the scanning probe allows the use of precise virtual apertures much smaller and more variable in shape than those used in conventional dark field imaging such that even buried interfaces marginally twisted from other layers can be targeted. With a coarse-grained form of dark field ptychography, BI uses simple physically derived fitting functions to extract the average structure within the illumination region and is, therefore, viable over large fields of view. BI has shown a particular advantage for selectively investigating the interlayer stacking and associated moiré reconstruction of bilayer interfaces within complex multi-layered structures. This has enabled investigation of reconstruction and substrate effects in bilayers through encapsulating hexagonal boron nitride and of select bilayer interfaces within trilayer stacks. However, the technique can be improved to provide a greater spatial resolution and probe a wider range of twisted structures, for which current limitations on acquisition parameters can lead to large illumination regions and the computationally involved post-processing can fail. Here, we analyze these limitations and the computational processing in greater depth, presenting a few methods for improvement over previous works, discussing potential areas for further expansion, and illustrating the current capabilities of this approach for extracting moiré-scale strain. [ABSTRACT FROM AUTHOR]

Domain boundaries in perovskite oxides often exhibit abundant physical properties and phenomena. Here, epitaxial LaTiO3 thin films on (100) SrTiO3 substrates are prepared by pulsed-laser deposition. X-ray diffraction and transmission electron microscopy investigations reveal that the epitaxial LaTiO3 thin films have good crystallinity but a high density of domain boundaries. Atomic-scale scanning transmission electron microscopy observations reveal that two types of domain boundaries are formed in the LaTiO3 thin films. The type I domain boundaries are formed on the {100} crystal planes, while the type II domain boundaries on the {110} crystal planes. Electron energy-loss spectroscopy analyses suggest that the valence states of Ti ions at the type I domain boundaries are +3, while those at the type II domain boundaries are +4. First-principles calculations reveal that the bandgap decreases at both domain boundaries compared to the bulk. The carrier concentration at the type I domain boundaries is significantly higher than that of the bulk, while the carrier concentration at the type II domain boundaries is lower. These findings suggest that domain boundaries play an important role in tailoring the electrical properties of the LaTiO3 thin films, thereby promoting the potential applications and property modulation of related materials and devices. [ABSTRACT FROM AUTHOR]

We report on the synthesis, crystal, and electronic structure, as well as the magnetic, and electric properties of the phosphorus‐containing tantalum nitride P1−xTa8+xN13 (x=0.1–0.15). A high‐pressure high‐temperature reaction (8 GPa, 1400 °C) of Ta3N5 and P3N5 with NH4F as a mineralizing agent yields the compound in the form of black, rod‐shaped crystals. Single‐crystal X‐ray structure elucidation (space group C2/m (no. 12), a=16.202(3), b=2.9155(4), c=11.089(2) Å, β=126.698(7)°, Z=2) shows a network of face‐ and edge‐sharing Ta‐centered polyhedra that contains small vacant channels and PN6 octahedra strands. Atomic resolution transmission electron microscopy reveals an unusual P/Ta disorder. Mixed‐valent tantalum atoms exhibit interatomic distances similar to those in metallic tantalum, however, the electrical resistivity is quite high in the order of 101 Ω cm. The density of states and the electron localization function indicate localized electrons in both covalent and ionic bonds between P/Ta and N atoms, combined with less localized electrons that do not contribute to interatomic bonds. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the bond strength of the calcium silicate-based sealer (CSS) modified with the silver nanoparticles (AgNPs) using the single-cone technique (SC) and the continuous wave condensation (CWC) technique, measured by a universal testing machine. The AgNPs and the modified sealers were characterized by scanning electron microscopy and transmission electron microscopy. One hundred single-rooted extracted human permanent teeth with a single root canal were cleaned and shaped with a Protaper Next system. The teeth were randomly divided into four groups (n = 25) as follows: Group 1, canals were obturated using the SC technique with TotalFill® BC Sealer. Group 2, canals were obturated using the SC technique with TotalFill® BC Sealer mixed with AgNPs. Group 3, canals were obturated using the CWC technique with TotalFill® HiFlow BC Sealer. Group 4, canals were obturated using the CWC technique with TotalFill® HiFlow BC Sealer mixed with AgNPs. After two weeks, 1 mm-thick dentin slices were cut and exposed to a push-out bond strength test using a universal testing machine. Specimens were examined under a digital microscope to determine the mode of failure. Statistical analysis was performed using ANOVA and Tukey multiple comparison tests (p < 0.05). The nanoparticle characterization revealed a spherical morphology with no obvious aggregations. The results showed that group 4 had the highest dislodgement resistance compared to all groups (p < 0.05). Group 4 was significantly higher in push-out bond strength value than group 1 (p < 0.001) and group 3 (p < 0.003), but not significantly higher than group 2. Cohesive failure was the most prevalent failure mode among all groups. It can be concluded that the incorporation of silver nanoparticles into the calcium silicate-based sealer significantly increased the bond strength. The warm obturation approach demonstrated significantly higher resistance to dislodgment as compared to the single-cone technique. [ABSTRACT FROM AUTHOR]

Purpose: The reliability of solder joints is closely related to the growth of an intermetallic compound (IMC) layer between the lead-free solder and substrate interface. This paper aims to investigate the growth behavior of the interfacial IMC layer during isothermal aging at 125°C for Sn-3Ag-3Sb-xIn/Cu (x = 0, 1, 2, 3, 4, 5 Wt.%) solder joints with different In contents and commercial Sn-3Ag-0.5Cu/Cu solder joints. Design/methodology/approach: In this paper, Sn-3Ag-3Sb-xIn/Cu (x = 0, 1, 2, 3, 4, 5 Wt.%) and commercial Sn-3Ag-0.5Cu/Cu solder were prepared for bonding Cu substrate. Then these samples were subjected to isothermal aging for 0, 2, 8, 14, 25 and 45 days. Scanning electron microscopy and transmission electron microscopy were used to analyze the soldering interface reaction and the difference in IMC growth behavior during the isothermal aging process. Findings: When the concentration of In in the Sn-3Ag-3Sb-xIn/Cu solder joints exceeded 2 Wt.%, a substantial amount of InSb particles were produced. These particles acted as a diffusion barrier, impeding the growth of the IMC layer at the interface. The growth of the Cu3Sn layer during the aging process was strongly correlated with the presence of In. The growth rate of the Cu3Sn layer was significantly reduced when the In concentration exceeded 3 Wt.%. Originality/value: The addition of In promotes the formation of InSb particles in Sn-3Ag-3Sb-xIn/Cu solder joints. These particles limit the growth of the total IMC layer, while a higher In content also slows the growth of the Cu3Sn layer. This study is significant for designing alloy compositions for new high-reliability solders. [ABSTRACT FROM AUTHOR]

The development of low-cost, highly effective, environmentally friendly, multi-functional bio-cidal substances has become a top priority in the current scenario. This study aimed to create low-cost materials, such as green-engineered magnesium oxide (GEMgO) and chitosan-coated magnesium oxide (GECsMgO) nanoparticles (NPs), using Chara zeylanica Klein ex Willd extract as a reducing agent. The X-ray diffraction results confirmed the cubic face-centered structure of the GEMgO and GECsMgO NPs. The field emission scanning electron microscopy and transmission electron microscopy results showed that GEMgO and GECsMgO NPs exhibit a spherical structure and nanoflakes with spherical structures, respectively. The Mg–O stretching frequencies were measured at 779 and 456 cm−1 for GEMgO and 543 cm−1 for GECsMgO NPs in the Fourier-transform infrared spectra. The oxygen vacancies responsible for the biocidal activities of GEMgO and GEC-MgO NPs were observed in their photoluminescence spectra at 501 and 520 nm and at 506 and 524 nm, respectively. The antioxidant activity of GEMgO and GECsMgO NPs was investigated using a DPPH assay. The GECsMgO NPs exhibited higher scavenging activity than the GEMgO NPs. Antibacterial studies on gram-negative bacteria treated with GEMgO and GECsMgO NPs showed that GECsMgO NPs exhibited the highest antibacterial activity. The ultrastructural morphological results of E. coli showed that GECsMgO NPs can damage it better than GEMgO NPs. An MTT assay determined that GEC-MgO NPs had better anticancer properties than GEMgO NPs when tested against a blood cancer cell line (MOLT-7). Fibroblast L929 cell toxicity tests showed that GEC-MgO NPs were less toxic than GEMgO NPs. In the future, GECsMgO NPs can be used as biocidal agents in clinical and industrial applications. • GEMgO and GECsMgO nanoparticles were synthesized using the Green Engineering method. • GECsMgO NPs exhibit higher antibacterial activity against gram-negative bacteria than GEMgO NPs. • GECsMgO NPs exhibit potential anticancer activity against blood cancer cell lines. • GECsMgO NPs were less harmful to fibroblast cells than GEMgO NPs. [ABSTRACT FROM AUTHOR]

The structure and electron emission properties of scanning tunneling microscope tips electrochemically etched from polycrystalline and recrystallized tungsten wires were investigated using scanning electron microscopy and transmission electron microscopy. Tips etched using the recrystallized wire had single crystal domains larger than those seen in tips etched from the cold drawn wire. The stability of the tips under high electric fields was investigated using field emission. It was found that tips etched from the recrystallized wire tended to have improved stability compared to those etched from the polycrystalline wire and that annealing either type of tip to high temperature in ultra-high vacuum had the greater influence on tip stability. [ABSTRACT FROM AUTHOR]

Dopant‐induced microstructure in thermoelectric materials significantly affects thermoelectric properties and offers a potential to break the interdependence between electron and phonon transport properties. However, identifying all‐scale dopant‐induced microstructures and correlating them with thermoelectric properties remain a huge challenge owing to a lack of detailed microstructural characterization encompassing all length scales. Here, the hierarchical boron (B)‐induced microstructures in B‐doped Si80Ge20 alloys with different B concentrations are investigated to determine their precise effects on thermoelectric properties. By adopting a multi‐scale characterization approach, including X‐ray diffraction, scanning and transmission electron microscopy, and atom probe tomography, five distinctive B‐induced phases within Si80Ge20 alloys are identified. These phases exhibit different sizes, compositions, and crystal structures. Furthermore, their configuration is comprehensively determined according to B doping concentrations to elucidate their consequential impact on the unusual changes in carrier concentration, density‐of‐states effective mass, and lattice thermal conductivity. The study provides insights into the intricate relationship between hierarchical dopant‐induced microstructures and thermoelectric properties and highlights the importance of investigating all‐scale microstructures in excessively‐doped systems for determining the precise structure‐property relationships. [ABSTRACT FROM AUTHOR]

The dynamic mechanical behaviour of high-alloyed powder metallurgical high-speed steel ASP 60 is investigated using a compressive split-Hopkinson pressure bar at strain rates of 2.5 × 10³ and 4.0× 10³ s-1 and temperatures of -195°C and 800°C, respectively. The effects of the strain rate and temperature on the microstructure evolution of the impacted specimens are examined using scanning electron microscopy and transmission electron microscopy. A negative strain rate sensitivity is observed at both temperatures. The flow stress, strain rate sensitivity, temperature sensitivity, fracture mechanism, and dislocation substructures are all significantly affected by the strain rate and temperature. The SEM fractographs reveal a brittle fracture mode at _195°C and localized melting at 800°C. The specimens impacted at _195°C exhibit a dislocation multiplication microstructure entangled with fine precipitates, which collectively increase the flow resistance of the sample. However, the microstructures of the specimens impacted at 800°C show a lower density of dislocations and coarse precipitates, resulting in a loss of flow resistance. The flow stress of the ASP 60 specimens shows a linear decrease with the square root of the dislocation density at both temperatures. The rate of decrease in the flow stress is higher under a cryogenic temperature. Hence, the relationship between the dislocation density and the mechanical response is inferred to be temperature-dependent. [ABSTRACT FROM AUTHOR]

Due to their high specific strength and low density, 7075 Al alloys are widely used in aerospace applications. However, Al alloys are prone to corrosion and deterioration, and the service life depends on their corrosion resistance. To investigate the corrosion and strengthening mechanisms of the 7075 Al alloy subjected to cold rolling, x-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to characterize the sample microstructure. Compared to the homogenized samples, the ultimate tensile strength of a cold-rolled sample increased from 235 ± 4 MPa to 347 ± 3 MPa when the thickness reduction increased to 50%. The yield strength approached 305 ± 0.4 MPa, and the tensile ductility decreased up to 62.9%. The cold-rolling process resulted in a significant increase in dislocation density and a reduction in grain size. The increased density of grain boundaries and the fragmentation of the precipitates led to a reduction in galvanic coupling with the Al matrix, resulting in the improved corrosion resistance of the 7075 Al alloy. This study provides a suitable approach to enhance both the mechanical properties and corrosion resistance of Al alloys. [ABSTRACT FROM AUTHOR]

After a brief review of the history of pearlite structures in carbon steels, particularly on the pearlite formation mechanism, recent experimental investigations on the pearlite substructure are presented to express a distinct point of view. The water‐quenched high‐carbon pearlite substructure is investigated in detail by means of scanning electron microscopy and transmission electron microscopy. In the experimental observation results, it is shown that the cementite layer or ferrite layer in pearlite is composed of fine grains, which cannot be simply explained by traditional nucleation and grain growth mechanisms. However, the fine grain structure can be explained by the martensitic transformation products (twinned martensite with ultrafine grains of α–Fe and twinning boundaries ω–Fe (or ω–Fe3C)) and detwinning process. Upon tempering or detwinning, recrystallization of the ultrafine grains of both crystalline phases occurs to form the initial pearlite structure, while the grain size of both phases is still fine. The twinned martensite can be treated as the precursor of pearlite structure (pearlite nucleation stage), and the detwinning process can be regarded as the growth of the pearlite structure. Thus, the pearlite reaction can be described as follows: austenite → twinned martensite → pearlite. [ABSTRACT FROM AUTHOR]

Multimodal measurements involving time‐resolved Ni and Cu K edges Quick‐EXAFS, time‐resolved hyperspectral Full Field Quick‐EXAFS imaging with micrometer spatial resolution and aberration‐corrected Environmental Scanning Transmission Electron Microscopy have been performed over a NiCu catalyst used for the ethanol steam reforming reaction to establish structure‐activity relationships after regeneration. Activated catalysts are composed of 5–10 nm monometallic nickel nanoparticles and larger bimetallic randomly alloyed NiCu nanoparticles (NPs). After 3 h time on reactive stream, the monitoring of the regeneration of the coked deactivated catalyst at 500 °C by Full Field hyperspectral XAS imaging evidences that the oxidative propagation front affects faster metallic Ni species than metallic Cu ones as a result of the stronger oxophilic character of the former compared to the latter. Furthermore, ESTEM characterization of the deactivated catalyst when passing from H2 to O2 atmosphere at 500 °C for burning coke deposits evidences the fragmentation of the Ni and NiCu‐NPs driven by the Kirkendall effect in the encapsulated coked catalyst. The resulting increase of specific surface of active species is assumed to be responsible for the activity boost observed after regeneration. [ABSTRACT FROM AUTHOR]

The phenomenon of rapid phase transition induced by electroshock treatment (EST) in metals has been widely observed, but its kinetic process is rarely quantitatively analyzed. In this work, the dissolution of the second phases in the Al–Zn–Mg–Cu alloys caused by EST was investigated using scanning electron microscopy and transmission electron microscopy. It was found that EST can sufficiently dissolve nanoscale precipitates, Al2CuMg phases and the short rod-shaped dispersed phases in the alloys. Additionally, a non-isothermal dissolution kinetics model has been proposed to depict the dissolution process of the second phase in the Al–Zn–Mg–Cu alloys during EST. The evolution laws and key factors of the second phase dissolution during EST were obtained by numerically solving these models. The solving results are basically consistent with the phenomena monitored in the experiment. These models are expected to be adopted to illustrate the phase transition induced by EST in other metal materials. [ABSTRACT FROM AUTHOR]

Polymeric composites for manipulating the sustained release of an encapsulated active ingredient are highly sought after for many practical applications; particularly, water-insoluble polymers and core–shell structures are frequently explored to manipulate the release behaviors of drug molecules over an extended time period. In this study, electrospun core–shell nanostructures were utilized to develop a brand-new strategy to tailor the spatial distributions of both an insoluble polymer (ethylcellulose, EC) and soluble polymer (polyvinylpyrrolidone, PVP) within the nanofibers, thereby manipulating the extended-release behaviors of the loaded active ingredient, ferulic acid (FA). Scanning electron microscopy and transmission electron microscopy assessments revealed that all the prepared nanofibers had a linear morphology without beads or spindles, and those from the coaxial processes had an obvious core–shell structure. X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopic tests confirmed that FA had fine compatibility with EC and PVP, and presented in all the nanofibers in an amorphous state. In vitro dissolution tests indicated that the radical distributions of EC (decreasing from shell to core) and PVP (increasing from shell to core) were able to play their important role in manipulating the release behaviors of FA elaborately. On one hand, the core–shell nanofibers F3 had the advantages of homogeneous composite nanofibers F1 with a higher content of EC prepared from the shell solutions to inhibit the initial burst release and provide a longer time period of sustained release. On the other hand, F3 had the advantages of nanofibers F2 with a higher content of PVP prepared from the core solutions to inhibit the negative tailing-off release. The key element was the water permeation rates, controlled by the ratios of soluble and insoluble polymers. The new strategy based on core–shell structure paves a way for developing a wide variety of polymeric composites with heterogeneous distributions for realizing the desired functional performances. [ABSTRACT FROM AUTHOR]

Rapid connectivity homogenization and ultra-probe sonication were used to manufacture the Azelic acid nanoemulsion. Everything is dissolved in clean water: Azelic acid, polyvinyl alcohol, xanthan gum, castor oil, vitamin E, Transcutol P, and Tween 80. To optimize it, we used Response Surface Methodology and measured a bunch of parameters, like droplet size (nm), surface morphology (FE-SEM, TEM), zeta potential (ZP), differential scanning calorimetry (DSC), polydispersity index (PDI), stability, pH, and viscosity. Both the penetration and retention of the Azelic acid -loaded nanoemulsion into the skin and its release profile were studied in vitro and ex vivo, respectively. The model's quadratic polynomial fitness was confirmed by the optimization analysis of variance (ANOVA), which yielded a significant F-value and a p-value below 0.0500. It was also determined that the lack-of-fit was not statistically significant. Globule size was 200 nm, PDI was 0.2, and entrapment efficacy was 84.99% following optimization of the Azelic acid nanoemulsion. A value of - 35.90 mV was recorded for the Zeta Potential (ZP). The absence of chemical interactions was verified by the findings of FTIR, DSC, and XRD investigations, which demonstrated the effective trapping of Azelic acid. Results from scanning electron microscopy and transmission electron microscopy revealed the presence of small spherical particles in the enhanced formulation. Centrifugation, freezethaw cycles, and storage at 5°C and 25°C were all successfully completed by the sample in the stability tests. Storage at 40°C for 7 weeks resulted in subtle color shifts, most noticeably during the last week of the study. The results of the rheological tests showed that the revised recipe is elastic and May shear-thin and pseudo-plastic. Over the course of 12 hours, the Azelic acid nanoemulsion released 87.66 % and 97.99 of its active ingredient. A high degree of linearity was demonstrated by the sustained release pattern, which matched a zero-order kinetic model (R2 = 0. 0.9952). After 8 hours, the Azelic acid nanoemulsion had an ex vivo penetration rate of 82.24 %, indicating better skin distribution. Based on the results, Azelic acid nanoemulsion might be useful as a skin condition topical therapy. Nevertheless, further research, including studies conducted in living organisms, is necessary to prove that azelic acid nanoemulsion is both efficient and safe. [ABSTRACT FROM AUTHOR]

Personal protective equipment (PPE) has attracted more attention since the outbreak of the epidemic in 2019. Advanced nano techniques, such as electrospinning, can provide new routes for developing novel PPE. However, electrospun antibacterial PPE is not easily obtained. Fibers loaded with photosensitizers prepared using single-fluid electrospinning have a relatively low utilization rate due to the influence of embedding and their inadequate mechanical properties. For this study, monolithic nanofibers and core–shell nanofibers were prepared and compared. Monolithic F1 fibers comprising polyethylene oxide (PEO), poly(vinyl alcohol-co-ethylene) (PVA-co-PE), and the photo-antibacterial agent vitamin K3 (VK3) were created using a single-fluid blending process. Core–shell F2 nanofibers were prepared using coaxial electrospinning, in which the extensible material PEO was set as the core section, and a composite consisting of PEO, PVA-co-PE, and VK3 was set as the shell section. Both F1 and F2 fibers with the designed structural properties had an average diameter of approximately 1.0 μm, as determined using scanning electron microscopy and transmission electron microscopy. VK3 was amorphously dispersed within the polymeric matrices of F1 and F2 fibers in a compatible manner, as revealed using X-ray diffraction and Fourier transform infrared spectroscopy. Monolithic F1 fibers had a higher tensile strength of 2.917 ± 0.091 MPa, whereas the core–shell F2 fibers had a longer elongation with a break rate of 194.567 ± 0.091%. Photoreaction tests showed that, with their adjustment, core–shell F2 nanofibers could produce 0.222 μmol/L ·OH upon illumination. F2 fibers had slightly better antibacterial performance than F1 fibers, with inhibition zones of 1.361 ± 0.012 cm and 1.296 ± 0.022 cm for E. coli and S. aureus, respectively, but with less VK3. The intentional tailoring of the components and compositions of the core–shell nanostructures can improve the process–structure–performance relationship of electrospun nanofibers for potential sunlight-activated antibacterial PPE. [ABSTRACT FROM AUTHOR]

The efficient removal of Cr(VI) from water is a crucial environmental concern, and in this study, the focus was on addressing this issue by investigating a new flower-like cerium phosphate polyaniline nanocomposite (CePO4-PANI) material. This material was synthesized using an in situ oxidative polymerization method, resulting in a flower-like morphology that was confirmed through field emission scanning electron microscopy and transmission electron microscopy images. The adsorption of Cr(VI) onto the material followed the pseudo-second-order kinetic model and the Langmuir isotherm model, with a high adsorption capacity of 129.87 ± 2.1 mg g−1 at room temperature in a wide pH range of 2 to 6. The CePO4-PANI nanocomposite is a promising adsorbent for the treatment of Cr(VI), with high tolerance to co-anions and efficient regeneration after multiple adsorption-desorption cycles. XPS spectra revealed the simultaneous adsorption of Cr(VI) and in situ chemical reduction to Cr(III) via electrostatic attractions and chelation methods. Its unique flower-like morphology, coupled with its impressive adsorption capacity, co-anion tolerance, and efficient regeneration, make it a promising alternative to existing technologies for water treatment. [ABSTRACT FROM AUTHOR]

Stenotrophomonas maltophilia (S. maltophilia) is a spoilage microorganism widely distributed in vegetables, dairy products, and various environments and can cause serious foodborne illnesses. Renowned for its environmentally friendly, safe, and non-toxic properties, rose essential oil (REO) is widely recognized as an exceptional natural antibacterial agent. In the present study, we conducted a comprehensive analysis to elucidate the inhibition mechanism of REO against S. maltophilia at both cellular and metabolic levels. The results demonstrated that REO treatment of cells resulted in the disruption of cell structure and leakage of cellular contents. Remarkable changes in the morphology of bacterial cells were observed under both scanning electron microscopy and transmission electron microscopy. At the metabolic level, multiple metabolic pathways were disrupted after REO treatment, including amino acid metabolism, nucleotide metabolism, and aminoacyl tRNA biosynthesis. These results shed new light to the inhibition mechanism of REO against S. maltophilia and provide a theoretical basis for the development of effective essential oil preservatives. [ABSTRACT FROM AUTHOR]

Understanding the structural stability of nanomaterials such as nanowires is imperative for their practical applications. Here, using single-shot ultrafast transmission electron microscopy, we captured the Plateau-Rayleigh instability behavior of silver nanowires decomposing into silver nanoparticles upon laser irradiation on nanosecond time scales. We found that this dynamic process can be accelerated by a factor of 10 through increasing the peak laser fluence from 6.03 to 14.60 mJ/cm2. Moreover, by comparing the laser fluence required to initiate the Plateau-Rayleigh instability in silver nanowires on carbon and Formvar membranes, it was found that the main driving force for the Plateau-Rayleigh instability in this study was substrate heating. Finite element analysis and molecular dynamics simulations are also applied to estimate the temperature jump of the nanowires and atomistic behavior, respectively. In addition, the complex motions of silver nanowires under laser irradiation were systematically investigated by combining the results of ultrafast transmission electron microscopy with scanning electron microscopy characterizations and were determined to be related to nanowire-membrane interactions or pre-existing stresses on the nanowires, which in turn demonstrated the potential of ultrafast transmission electron microscopy for the characterization of nanomaterials and devices under extreme conditions. [ABSTRACT FROM AUTHOR]

Chemically ordered face-centered cubic (fcc) phases consisting mainly of Cr, Co, and Ni were synthesized by annealing a Cr26.7Co26.7Ni26.7Si10B5P5 amorphous alloy. The annealed Cr26.7Co26.7Ni26.7Si10B5P5 sample was composed of Cr4.5BP2, Cr3 Co5Si2, and fcc phases. Synchrotron radiation anomalous X-ray scattering (AXS) measurements confirmed that the annealed Cr26.7Co26.7Ni26.7Si10B5P5 sample had superlattice reflections from an L10-, and/or L12-, and D022-type ordered structure. The diffraction intensities of the superlattice reflections observed in the AXS measurements indicated strong dependence on the incident X-ray energy. The diffraction intensity of the superlattice reflection increased at the X-ray energy near the K-edge of Cr, suggesting that Cr is mainly ordered in the L10- and D022-type structures. Microstructural analysis using scanning transmission electron microscopy (STEM) revealed crystal grains with diameters of approximately 20 nm, showing diffraction spots corresponding to superlattice reflections of 001 and 110, in addition to a two-dimensional diffraction pattern corresponding to the fcc structure. Simultaneous STEM--energy dispersive X-ray spectroscopy analysis indicated that the grains had a higher Cr concentration than the mother alloy composition of Cr26.7Co26.7Ni26.7Si10B5P5. [ABSTRACT FROM AUTHOR]

The herbicidal activity of the fermentation broth, filtrate, and extracts of Bacillus altitudinis D30202 was evaluated against seed germination and seedling growth of wild oat (Avena fatua L.). The bacterial culture filtrate exhibited greater inhibition of the wild oat weed than the fermentation broth. The filtrate was also extracted with organic solvents. The herbicidal potency of the extracts on the growth of wild oat plants was as follows: chloroform (100% inhibition of germination) > n-butanol (93.8%) > ethyl acetate (66.7%) > petroleum ether (6.3%) > aqueous phase (2.1%); so the chloroform extract was evaluated further. It inhibited wild oat radicle growth by 100%, and plumule growth by 97.9%, while spraying young plants with a 5 mg/mL extract caused severe desiccation of the leaves, stalk wilting, and plant death. IC50 values for inhibition of plumule and radicle growth and germination were 0.64– 0.72 mg/mL. Scanning electron microscopy and transmission electron microscopy revealed changes in the microstructure of the leaves and root tips, and degradation of organelles following chloroform extract treatment. The 5 mg/mL extract had no adverse impact on the growth or health of highland barley (Hordeum vulgare L.), corn (Zea mays), and broad bean (Vicia faba L.), indicating that this novel bioherbicide is suitable for control of wild oat weeds in the production of these food crops (while having a minor impact on the health of pea plants and being phytotoxic to wheat plants). [ABSTRACT FROM AUTHOR]

This study presents a novel approach to synthesize zinc oxide (ZnO) nanoparticles using a polymer precursor method, offering precise control over particle size in the nanometer scale. Zinc oxide nanoparticles are of significant interest due to their wideranging applications in various fields such as solar cells, gas sensors, photocatalysts, and nanomedicines. The synthesized nanoparticles were thoroughly characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared spectroscopy (FTIR). The distinct hexagonal form detected in the XRD pattern, featuring characteristic reflection planes at angles of 31.72° (100), 34.39° (002), 36.23° (101), and 47.44° (102), signifies the synthesis of ZnO possessing a hexagonal wurtzite structure. The SEM and TEM images revealed uniformly spherical particles with an average size ranging from 35 to 40 nm. Such uniform morphology and size distribution are critical for ensuring consistent performance in applications such as gas sensing and catalysis. Additionally, the FTIR spectra indicated a reduction in impurities after the synthesis process, highlighting the effectiveness of the polymer precursor method in producing high-quality ZnO nanoparticles. Heating the ZnO precursor material at 400°C for 2 hours significantly reduces impurities, suggesting conversion to ZnO nanoparticles. [ABSTRACT FROM AUTHOR]

The structure, composition, and spatial distribution heterogeneity of artificial pinning centers affect the critical current density of REBa2Cu3O7−y (RE: rare earth) coated conductors. Nanoscale structures and compositions have been analyzed with transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). However, microscale heterogeneity has been difficult to characterize. Here, YBa2Cu3O7−y thin films doped with double-perovskite Ba2YbNbO6 were prepared via pulsed-laser deposition and characterized with TEM, STEM, and scanning electron microscopy (SEM). Cross-sectional and plan-view TEM/STEM imaging revealed hybrid pinning structures consisting of nanorods, nanoparticles, and planar defects that were formed spontaneously. Nanorods were imaged with high spatial resolution via field-emission SEM of thin-foil specimens. Focused-ion-beam (FIB) micro-sectioning enables SEM imaging of microscale heterogeneity in nanorod spatial distributions. By using TEM/STEM in conjunction with FIB-SEM, the coated conductor inhomogeneity was directly evaluated from the nano- to micrometer scales. [ABSTRACT FROM AUTHOR]

Evaluating ion-conductive solid electrolytes (SEs) accurately is crucial for advancing solid-state battery technology. Scanning/transmission electron microscopy (S/TEM) is a valuable technique for examining the local characteristics of battery materials. However, the tolerance of SEs to high-energy electron beams is notably lower than that of electrode active materials, because SEs generally have low electron conductivity. Here, we propose a specialized coating technique for TEM samples, termed "nano-shield," which enables stable and accurate observation of their micro-/nano-structures. Nano-shield consists of a dual-layer coating combining an amorphous insulating layer of aluminum oxide (AlOx) with a conductive carbon (C) film. The AlOx layer blocks ion diffusion in the TEM samples, and the C layer minimizes electron charging during electron-beam irradiation. By applying a nano-shield, we successfully visualized the atomic structures of a lithium-ion-conductive SE, Li1.3Al0.3T1.7(PO4)3 (LATP), by using STEM at room temperature. Additionally, we performed a precise elemental analysis of a sodium-ion-conductive SE, Na3Zr2Si2PO12 (NZSP), via STEM equipped with energy-dispersive X-ray spectroscopy (STEM-EDS). Our findings demonstrate that nano-shield enhances the reliability of S/TEM observations of SEs and sheds light on its underlying protective mechanisms. [ABSTRACT FROM AUTHOR]

Group 10 transition metal dichalcogenide PtSe2 has drawn considerable attention toward the search for an efficient visible light photocatalyst due to its strong light–matter interaction nature. Here we report PtSe2/TiO2 heterostructure for solar energy conversion through photoelectrochemical (PEC) water splitting. The PtSe2/TiO2 heterostructure was prepared by sputtered Pt film followed by the chemical vapor deposition method. Raman spectroscopy and X-ray diffraction analysis confirmed the growth of hexagonal phase PtSe2 and anatase TiO2 corresponding to their distinguished peak characteristics. The field-emission scanning electron microscopy and transmission electron microscopy studies reveal that TiO2 nanotubes were decorated with PtSe2 nanoflakes forming PtSe2/TiO2 heterostructure. The chemical composition of the prepared samples was studied by using the X-ray photoelectron spectroscopy and indicated the sole presence of PtSe2 and TiO2 compounds. The PEC measurements were taken in 0.5 M Na2SO4 electrolyte solution under simulated sunlight (AM = 1.5 G). The maximum photocurrent density of ~ 234.7 µA/cm2 at 1.4 V versus RHE was recorded for PtSe2/TiO2 heterostructure, which is 1.7 times higher than that of Pt/TiO2. The improved PEC performance of PtSe2/TiO2 as a result of efficient solar absorption over a wider spectrum and effective charge separation produced by type-II band alignment between PtSe2 and TiO2. [ABSTRACT FROM AUTHOR]

A ZnO-Graphene oxide nanocomposite (Z-G) was prepared in order to exploit the biomedical features of each component in a single anticancer material. This was achieved by means of an environmentally friendly synthesis, taking place at a low temperature and without the involvement of toxic reagents. The product was physicochemically characterized. The ZnO-to-GO ratio was determined through thermogravimetric analysis, while scanning electron microscopy and transmission electron microscopy were used to provide insight into the morphology of the nanocomposite. Using energy-dispersive X-ray spectroscopy, it was possible to confirm that the graphene flakes were homogeneously coated with ZnO. The crystallite size of the ZnO nanoparticles in the new composite was determined using X-ray powder diffraction. The capacity of Z-G to enhance the toxicity of the anticancer drug Paclitaxel towards breast cancer cells was assessed via a cell viability study, showing the remarkable anticancer activity of the obtained system. Such results support the potential use of Z-G as an anticancer agent in combination with a common chemotherapeutic like Paclitaxel, leading to new chemotherapeutic formulations. [ABSTRACT FROM AUTHOR]

2D orthorhombic palladium diselenide is attracting rapidly increased interest by virtue of its fascinating physical properties and feasibility of phase transformation. However, it remains a major challenge to produce ultrathin PdSe2 through a facile chemical route and control phase transformation because of its anisotropic structure with strong interlayer coupling. Here, the efficient synthesis of few‐layer PdSe2 nanosheets with large sizes using an electrochemical exfoliation approach is reported. Upon thermal annealing at 300–350 °C, the as‐exfoliated PdSe2 nanosheets transform into metallic phase PdSe2‐x, as verified by scanning transmission electron microscopy, Raman spectroscopy, and electrical characterizations. Simple encapsulation using hexagonal boron nitride (h‐BN) can effectively suppress the Se‐loss triggered phase transformation, so that a metal‐semiconductor junction is formed by local phase modification. The fabricated PdSe2 field‐effect transistors exhibit p‐type transport property, which is in stark contrast to electron‐dominated ambipolar transport of pristine PdSe2 devices. The combination of high‐resolution X‐ray photoelectron spectroscopy and cross‐sectional transmission electron microscopy analysis reveals that the modulation of carrier polarity in h‐BN encapsulated PdSe2 should arise from the p‐doping effect associated with the impact of interfacial condition. The study opens up a new route for future phase‐engineered electronics in PdSe2 and other 2D noble metal dichalcogenides materials. [ABSTRACT FROM AUTHOR]

A new and innovative rolled graphene oxide (roll‐GO)/poly‐m‐methylaniline (PmMA) core–shell nanocomposite has been successfully synthesized using an in situ polymerization technique. This eco‐friendly and cost‐effective material shows great promise due to its antimicrobial properties. The characterization of the nanocomposite involved X‐ray diffraction and Fourier transform infrared spectroscopy to analyze its structure and functional groups, whereas scanning electron microscopy and transmission electron microscopy (TEM) were utilized to examine its morphology. TEM analysis revealed the formation of roll‐GO, forming multi‐walled tubes with inner and outer diameters of 50 and 70 nm, respectively. Optical analysis demonstrated an enhanced bandgap in the nanocomposite, with bandgap values of 2.38 eV for PmMA, 2.67 eV for roll‐GO, and 1.65 eV for roll‐GO/PmMA. The antibacterial efficacy of the nanocomposite was tested against Gram‐positive bacteria, including Bacillus subtilis and Staphylococcus aureus, as well as Gram‐negative bacteria such as Escherichia coli and Salmonella sp. The well diffusion method was used to determine the inhibition zones, revealing that the nanocomposite demonstrated broad‐spectrum antibacterial activity against all the pathogens tested. The largest inhibition zones were observed for B. subtilis, followed by S. aureus, E. coli, and Salmonella sp. Notably, the inhibition zones increased when the samples were exposed to light compared to dark conditions, with increases of 33 and 18 mm noted for B. subtilis. This enhanced activity under light exposure is attributed to the photocatalytic properties of the nanocomposite. The antibacterial mechanism is based on both adsorption and degradation processes. Moreover, antibacterial activity was found to increase with increasing concentrations of nanoparticles, ranging from 100 to 500 ppm. This suggests that the nanocomposite has potential as an alternative to antibiotics, especially considering the growing issue of bacterial resistance. The promising results obtained from the inhibition zones make these nanocomposites suitable for various applications. Currently, the research team is working on the development of a prototype utilizing these antimicrobial particles within commercial bottles for sterilization purposes in factories and companies. [ABSTRACT FROM AUTHOR]

For synthesizing metal–organic molecules with pro‐drug properties to prevent the accumulation of amyloid beta (Aβ1–42), which is a feature of neurodegenerative Alzheimer's disease, two new Schiff bases with imine/amine donors 2‐([3,3‐diphenylalidene]amino)‐N,N‐dimethylethane‐1‐amine and N,N‐dimethyl‐2‐([quinolin‐4‐ylmethylene]amino)ethane‐1‐amine, as well as their novel Pt (II) complexes (I and II), were synthesized and characterized via Fourier transform infrared spectroscopy, 1H‐ and 13C‐nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and elemental analyses. The spectroscopic data has shown that the ligands are coordinated to the central atom in a chelating manner. Furthermore, the interaction between these complexes and Aβ1–42 was investigated using the electrochemical methods, square wave voltammetry and pencil graphite electrode, while monitoring the changes in the oxidation signal of the Try residue in Aβ1–42. The ability of the compounds to inhibit Aβ1–42 aggregation was investigated using the human neuroblastoma cell line (SH‐SY5Y). Complex II could actively inhibit the aggregation of Aβ1–42 at a molar ratio of 1.0/1.0, and its Aβ1–42 aggregation kinetics were fluorometrically determined using thioflavin T. These results were supported by scanning electron microscopy and transmission electron microscopy analyses. Moreover, the interaction of complex II with Aβ1–16 was investigated via 1H‐NMR spectroscopy. As a result, it was observed that complex II was effective in inhibiting the aggregation of Aβ1–42 at a molar ratio of 1.0/1.0. This result shows that studies can be conducted on the effects of Schiff base‐Pt complexes as potential pro‐drugs on Alzheimer's disease. [ABSTRACT FROM AUTHOR]

An ever-present limitation of transmission electron microscopy is the damage caused by high-energy electrons interacting with any sample. By reconsidering the fundamentals of imaging, we demonstrate an event-responsive approach to electron microscopy that delivers more information about the sample for a given beam current. Measuring the time to achieve an electron count threshold rather than waiting a predefined constant time improves the information obtained per electron. The microscope was made to respond to these events by blanking the beam, thus reducing the overall dose required. This approach automatically apportions dose to achieve a given signal-to-noise ratio in each pixel, eliminating excess dose that is associated with diminishing returns of information. We demonstrate the wide applicability of our approach to beam-sensitive materials by imaging biological tissue and zeolite. [ABSTRACT FROM AUTHOR]

The monolithic integration of gallium phosphide (GaP), with its green band gap, high refractive index, large optical non-linearity, and broad transmission range on silicon (Si) substrates, is crucial for Si-based optoelectronics and integrated photonics. However, material mismatches, including thermal expansion mismatch and polar/non-polar interfaces, cause defects such as stacking faults, microtwins, and anti-phase domains in GaP, adversely affecting its electronic properties. Our paper presents a structural and defect analysis using scanning transmission electron microscopy, high-resolution transmission electron microscopy, and scanning nanobeam electron diffraction of epitaxial GaP islands grown on Si nanotips embedded in SiO2. The Si nanotips were fabricated on 200 mm n-type Si (001) wafers using a CMOS-compatible pilot line, and GaP islands were grown selectively on the tips via gas-source molecular-beam epitaxy. Two sets of samples were investigated: GaP islands nucleated on open Si nanotips and islands nucleated within self-organized nanocavities on top of the nanotips. Our results reveal that in both cases, the GaP islands align with the Si lattice without dislocations due to lattice mismatch. Defects in GaP islands are limited to microtwins and stacking faults. When GaP nucleates in the nanocavities, most defects are trapped, resulting in defect-free GaP islands. Our findings demonstrate an effective approach to mitigate defects in epitaxial GaP on Si nanotip wafers fabricated by CMOS-compatible processes. [ABSTRACT FROM AUTHOR]

Cerium oxide nanoparticles possess unique properties that make them promising candidates in various fields, including cancer treatment. Among the proposed synthesis methods for CNPs, biosynthesis using natural extracts, offers an eco-friendly and convenient approach for producing CNPs, particularly for biomedical applications. In this study, a novel method of biosynthesis using the aqueous extract of Eucalyptus camaldulensis leaves was used to synthesize CNPs. Scanning electron microscopy and Transmission electron microscopy (TEM) techniques revealed that the synthesized CNPs exhibit a flower-like morphology. The particle size of CNPs obtained using Powder X-ray diffraction peaks and TEM as 13.43 and 39.25 nm. Energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy confirmed the effect of biomolecules during the synthesis process and the formation of CNPs. The cytotoxicity of biosynthesized samples was evaluated using the MTT method demonstrating the potential of these samples to inhibit MCF-7 cancerous cells. The viability of the MCF-7 cell line conducted by live/dead imaging assay confirmed the MTT cytotoxicity method and indicated their potential to inhibit cancerous cells. Furthermore, the successful uptake of CNPs by MCF-7 cancer cells, as demonstrated by confocal microscopy, provides evidence that the intracellular pathway contributes to the anticancer activity of the CNPs. In general, results indicate that the biosynthesized CNPs exhibit significant cytotoxicity against the MCF-7 cancerous cell line, attributed to their high surface area. [ABSTRACT FROM AUTHOR]

Interactions at high temperatures between thin films and the Si substrate limit materials discovery using combinatorial processing platforms (CPPs). To overcome this, a diffusion and reaction barrier, SiO2, by thermal oxidation of Si tips is developed. The application of this diffusion barrier in CPPs for atomic‐scale investigations of new materials in atom probe tomography is reported. Thermal SiO2 layers (20 and 50 nm thick) are examined as barriers to separate coatings from Si tips. Pt is chosen as it easily forms silicides. CPPs are sequentially annealed in vacuum at 400 °C for 10 h, 600 °C for 2 h, and 800 °C for 2 h. The thermal SiO2 diffusion barrier remains stable and prevents intermixing at least up to 800 °C. Moreover, it provides improved film adhesion as dewetting of Pt on the oxide surface occurred at 800 °C instead of 600 °C without a thermal diffusion barrier. A comprehensive structural and chemical analysis of the Pt film, the thermal SiO2 layer, and their interfaces is performed using scanning and transmission electron microscopy, and atom probe tomography. As a result, the thermal SiO2 forms a stable barrier, even at the lowest thickness of 20 nm, avoiding the formation of Pt silicides, even at 800 °C. [ABSTRACT FROM AUTHOR]

Using the focused ion beam probe method, cross-section sample of a single functional device of micron dimensions were cut out for STEM and TEM studies. The use of analytical methods of transmission electron microscopy made it possible to obtain accurate data on the geometric parameters of nanoscale functional devices, the phase and elemental composition of functional element material, as well as on the concentration of free electrons at the Fermi level in the nanoelement material. [ABSTRACT FROM AUTHOR]

Cobalt oxide (Co3O4), a transition metal oxide known for its favourable capacitive properties and surface characteristics, is a promising candidate for electrode materials in supercapacitive energy storage applications. This study presents a comprehensive analysis of cobalt oxide nanoparticles synthesized through the hydrothermal method at varying synthesis temperatures, focusing on their structural, optical, electrochemical, and surface properties. X-ray diffraction analysis confirmed the cubic spinel structure of Co3O4, while Raman spectroscopy verified the phase composition of the nanoparticles. X-ray photoelectron spectroscopy offered insights into the near-surface chemistry of the synthesized material. The study determined two direct bandgaps of Co3O4 through absorption spectra and Tauc plots. To assess surface morphology and particle size distribution, field-emitting scanning electron microscopy and transmission electron microscopy were employed. Electrochemical investigations involved cyclic voltammetry and Nyquist plots, while galvanostatic charge–discharge tests demonstrated a specific capacitance ( C sp ) of 450 Fg−1 at 1 Ag−1. Impedance analysis indicated favourable capacitive behaviour with low charge transfer resistance. Furthermore, the study observed cyclic stability with a capacitive retention rate exceeding 88% at a current density of 20 Ag−1 over 10,000 cycles. The paper also discusses the capacitive and diffusion-controlled charge storage mechanisms at lower scan rates, emphasizing the potential of Co3O4 nanoparticles as the electrode material in the development of supercapacitor devices. [ABSTRACT FROM AUTHOR]

Simple Summary: The study focuses on the morphological characteristics and sensory structures of the antennae of G. italicum. The results indicate that there is no significant sexual dimorphism in the antennomeres and sensilla equipment. Six main types of sensilla were identified, including basiconic, trichoid, coeloconic, chaetic, campaniform, and peg sensilla. These sensilla were further categorized into subtypes based on their shape, length, and ultrastructure, with evidence supporting their functions as olfactory, thermo–hygroreceptors, and mechanoreceptors. The ultrastructure of the dendritic elements and pore systems of the sensilla, as well as the presence of inflexible/flexible sockets, provided insights into the primary functions of the sensilla. The distribution of sensilla varied across specific antennomeres, with distinct arrangements observed on the scapus, pedicel, basiflagellum, and distiflagellum. The study's findings provide detailed insights into the morphological and functional diversity of the antennal sensory structures in G. italicum, contributing to a comprehensive understanding of sensory perception in this species. The antennae of the shield bug Graphosoma italicum (Müller, 1766) were examined through scanning and transmission electron microscopy to reveal their general morphology, as well as the antennal sensilla's distribution, size, and ultrastructure of their dendrites and function. The antennae comprise five antennomeres (one scape, two pedicels, and two flagellomeres). Different lengths of chaetic mechanosensilla (Ch1-Ch4) exist on all antennomeres, and several highly sensitive campaniform sensilla are embedded in the exoskeleton and measure cuticular strain. One pair of peg sensilla, the typical proprioceptive, is only on the proximal edge of the first pedicel and directed to the distal edge of the scapus. The antennal flagellum possesses two subtypes of trichoid and basiconic sensilla, each with one type of coeloconic olfactory sensilla. The distinctive characteristics of G. italicum are also apparent in two subtypes of coeloconic sensilla embedded in different cavities on both antennomeres of the flagellum, probably with a thermo-hypersensitive function. All studied morphological types of the sensilla and their function were supported by ultrastructural elements. The long and thin trichoid sensilla type 2 (TrS2) with an olfactive function was the most abundant sensilla localized on both flagellomeres. The peripheral antennal sensilla system consists of six main types of sensilla divided into twelve subtypes. [ABSTRACT FROM AUTHOR]

The Al–Cu–Mg–Ag alloy after secondary aging of T6I4 was investigated by hardness measurement, tensile test, friction and wear test, exfoliation corrosion test, intergranular corrosion test, electrochemical corrosion test. Scanning electron microscopy and transmission electron microscopy were used to observe the alloy microstructure. The test results show that the secondary aging can improve the microstructure of the alloy, the mechanical and corrosion properties of the alloy. After single-stage aging at 185 °C for 2 h and interrupted aging at 120 °C for 9 h, the Ω phase in the alloy are fine and uniformly distributed, and the θ′ phase disappear to be obviously coarse. The hardness value, tensile strength, friction and wear coefficient, and loss weight of the alloy are 162.2 HV, 485 MPa, 1.780, and 10.8 mg, respectively. The corrosion resistance of the alloy was improved, and the exfoliation corrosion grade, intergranular corrosion depth, self-corrosion current density, and corrosion rate were 162.2 HV, 1.780, EA, 26.2 μm, 0.0028 mA cm−2, and 0.0915 mm a−1, respectively. [ABSTRACT FROM AUTHOR]

The present work reports on the structural and spectroscopic properties of Pr3+ doped ZnS nanoparticles in silicate glasses prepared by sol–gel technique. Structural characterization was performed by X-ray diffraction, Fourier-transform infrared, scanning electron microscopy and transmission electron microscopy. The structural studies reveal the presence of nanosized in the amorphous silica glass. Spectroscopic studies were performed through absorption and photoluminescence (PL) techniques. The radiative parameters such as transition probability (Aed), radiative lifetimes (τR), and branching ratios (βR), the Judd–Ofelt intensity parameters Ωλ were determined from the absorption spectra of the prepared samples. The increase absorption as well as PL intensity was observed. This enhanced intensity is observed due to the effective increased in oscillator strength of Pr3+ doped ZnS. We observed strong stimulated emission cross-sections for the transition 3P0 → 3H6, at 614 nm. It may be useful for good lasing material in reddish-orange region. CIE chromaticity coordinates were also evaluated from the emission spectra of each glass. The development of visible reddish-orange lasers may be effectively facilitated by SiZPr1.5 glass, as indicated by the observed emission cross-sections and CIE chromaticity coordinates. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this in vitro study was to assess the suitability of high-resolution time-of-flight secondary ion mass spectrometry (ToF-SIMS) for visualizing cross-sectional changes in human enamel microstructure and chemical composition during treatment and remineralization cycling of artificially generated caries lesions underneath an artificial plaque. Methods: Treatments consisted of exposure to twice daily toothpaste/water slurries prepared from 0, 1,100, and 5,000 μg/g fluoride (F) NaF/silica toothpastes. In addition, treatments with slurries prepared from 1,100 μg/g F SnF2/silica toothpastes were done using 44Ca in the remineralization solution to allow for differentiation of newly formed mineral and exploration of incorporated metal dopants using ToF-SIMS. Complementary microhardness, scanning electron microscopy, and high-resolution transmission electron microscopy (HR-TEM) investigations were performed on enamel cross sections. Results: HR-TEM was used for the first time to determine the change in crystallinity during remineralization revealing distinct microstructural zones within one lesion. Chemical mapping using ToF-SIMS demonstrated that the distribution of F, while observed primarily in the new mineral phase, was widespread throughout the lesion with 44Ca substantially limited to the remineralizing mineral. Both penetrated the inter-rod spaces of the sound enamel illustrating how acid damage propagates into the native mineral as the caries lesion deepens. HR-TEM examination revealed different regions within the lesion characterized by distinct micro- and ultrastructures. Importantly, HR-TEM revealed a return of crystallinity following remineralization. F dose-response observations verified the ability of these high-resolution techniques to differentiate remineralization efficacy. Conclusion: The collective results provided new insights such as the visualization of F or calcium penetration pathways, as well as new tools to study the caries process. [ABSTRACT FROM AUTHOR]

Introduction: Sodium pheophorbide a (SPA) is a natural plant-derived photosensitizer, with high photoactivated antifungal activity against some phytopathogenic fungi. However, its fungicidal effect on Diaporthe mahothocarpus, a novel pathogen that causes Camellia oleifera leaf spot blight, is unclear. Methods: In the present study, we explored its inhibitory effects on spore germination and mycelial growth of D. mahothocarpus. Then we determined its effects on the cell membrane, mycelial morphology, redox homeostasis, and cell death through bioassay. Finally, RNA-seq was used further to elucidate its mode of action at the transcriptional level. Results: We found that SPA effectively inhibited the growth of D. mahothocarpus, with half-maximal effective concentrations to inhibit mycelial growth and spore germination of 1.059 and 2.287 mg/mL, respectively. After 1.0 mg/mL SPA treatment, the conductivity and malondialdehyde content of D. mahothocarpus were significantly increased. Scanning electron microscopy and transmission electron microscopy indicated that SPA significantly affected the morphology and ultrastructure of D. mahothocarpus hyphae, revealing that SPA can destroy the mycelial morphology and cell structure, especially the cell membrane of D. mahothocarpus. Furthermore, transcriptome analysis revealed that SPA significantly suppressed the expression of genes involved in morphology, cell membrane permeability, and oxidative stress. Then, we also found that SPA significantly promoted the accumulation of reactive oxygen species (ROS) in of D. mahothocarpus, while it decreased the content of reduced glutathione, inhibited the enzyme activities of superoxide dismutase and catalase, and exacerbated DNA damage. Annexin V-FITC/PI staining also confirmed that 1.0 mg/mL SPA could significantly induce apoptosis and necrosis. Discussion: Generally, SPA can induce ROS-mediated oxidative stress and cell death, thus destroying the cell membrane and hyphal morphology, and ultimately inhibiting mycelial growth, which indicates that SPA has multiple modes of action, providing a scientific basis for the use of SPA as an alternative plant-derived photoactivated fungicide against C. oleifera leaf spot blight. [ABSTRACT FROM AUTHOR]

Monodisperse and semi-faceted ultra-small templated mesoporous silica nanoparticles (US-MSNs) of 20–25 nm were synthesized using short-time hydrolysis of tetraethoxysilane (TEOS) at room temperature, followed by a dilution for nucleation quenching. According to dynamic light scattering (DLS), a two-step pH adjustment was necessary for growth termination and colloidal stabilization. The pore size was controlled by cetyltrimethylammonium bromide (CTAB), and a tiny amount of neutral surfactant F127 was added to minimize the coalescence between US-MSNs and to favor the transition towards internal ordering. Flocculation eventually occurred, allowing us to harvest a powder by centrifugation (~60% silica yield after one month). Scanning transmission electron microscopy (STEM) and 3D high-resolution transmission electron microscopy (3D HR-TEM) images revealed that the US-MSNs are partially ordered. The 2D FT transform images provide evidence for the coexistence of four-, five-, and sixfold patterns characterizing an "on-the-edge" crystallization step between amorphous raspberry and hexagonal pore array morphologies, typical of a protocrystalline state. Calcination preserved this state and yielded a powder characterized by packing, developing a hierarchical porosity centered at 3.9 ± 0.2 (internal pores) and 68 ± 7 nm (packing voids) of high potential for support for separation and catalysis. [ABSTRACT FROM AUTHOR]

SnGe4N4O4 was synthesized at high pressure (16 and 20 GPa) and high temperature (1200 and 1500°C) in a large‐volume press. Powder X‐ray diffraction experiments using synchrotron radiation indicate that the derived samples are mixtures of known and unknown phases. However, the powder X‐ray diffraction patterns are not sufficient for structural characterization. Transmission electron microscopy studies reveal crystals of several hundreds of nanometres in size with different chemical composition. Among them, crystals of a previously unknown phase with stoichiometry SnGe4N4O4 were detected and investigated using automated diffraction tomography (ADT), a three‐dimensional electron diffraction method. Via ADT, the crystal structure could be determined from single nanocrystals in space group P63mc, exhibiting a nolanite‐type structure. This was confirmed by density functional theory calculations and atomic resolution scanning transmission electron microscopy images. In one of the syntheses runs a rhombohedral 6R polytype of SnGe4N4O4 could be found together with the nolanite‐type SnGe4N4O4. The structure of this polymorph was solved as well using ADT. [ABSTRACT FROM AUTHOR]

Background: Colletotrichum species are among the most common pathogens in agriculture and forestry, and their control is urgently needed. Methods: In this study, a total of 68 strains of biocontrol bacteria were isolated and identified from Photinia × fraseri rhizosphere soil. Results: The isolates were identified as Brevibacillus brevis by 16S rRNA. The inhibitory effect of TR-4 on Colletotrichum was confirmed by an in vitro antagonistic experiment. The inhibitory effect of TR-4 was 98% at a concentration of 10 µl/ml bacterial solution, protection of the plant and inhibition of C. siamense was evident. Moreover, the secretion of cellulase and chitosan enzymes in the TR-4 fermentation liquid cultured for three days was 9.07 mol/L and 2.15 µl/mol, respectively. Scanning electron microscopy and transmission electron microscopy confirmed that TR-4 destroyed the cell wall of C. siamense, resulting in leakage of the cell contents, thus weakening the pathogenicity of the bacteria. [ABSTRACT FROM AUTHOR]

In this work, pre-oxidized polyacrylonitrile fibers are treated with ultrasonic etching and solution etching to produce ultra-thin sections. The evolution of the fibers' microstructure in the pre-oxidation process is observed, and the transformation model of the microstructure of the pre-oxidized fibers is proposed. Scanning electron microscopy and high-resolution transmission electron microscopy were used to observe the microstructure changes of the fibers. Fourier transform infrared spectroscopy and X-ray diffraction were used to observe the chemical structure transformation and crystallization degree of the fibers in the pre-oxidation process. The results revealed that pre-oxidized fibers exhibited a smooth surface, while their interior consisted of fibrils. The longitudinal microfibrils were connected by the transverse microfibrils and amorphous regions. The fracture morphology of the fibers shifted from ductile to brittle, and the cross-section gradually became smoother. The linear molecular chain of PAN transformed into a ring structure as pre-oxidation progressed, subsequently leading to the cross-linking of this ring structure into an orderly trapezoidal configuration. The connection between the fibrils was enhanced, and the fiber structure became more compact and stable. [ABSTRACT FROM AUTHOR]

Transmission electron microscopy (TEM) facilitates the direct observation of individual catalytic materials with atomic-level spatial resolution, offering crucial structural insights into catalyst performance. Furthermore, the recent integration of in situ analysis techniques with TEM has enabled the real-time monitoring of dynamic structural changes in catalysts within a reaction environment over time, yielding novel findings that are challenging to obtain through conventional bulk characterization methods. In this prospective, we explore advanced TEM technologies employed for precisely examining the structure of a catalyst surface, emphasizing the dynamic chemistry inherent in heterogeneous catalysis, exclusively validated through in situ TEM. Finally, we propose future directions for in situ TEM studies on heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

The pervasive utilization of plastic as a cost‐effective packaging material for food has led to environmental concerns, primarily due to its non‐biodegradable nature and the ensuing release of carbon dioxide gas that contributes to global warming. In response to these challenges, researchers have shifted their focus toward biopolymers to develop eco‐friendly packaging solutions. The present study introduces a novel approach to study the release of micronutrient (Fe) from clay free starch‐glycerol film and clay‐starch‐glycerol composite film. The structural composition and characteristics of the synthesized film are meticulously examined using x‐ray diffraction (XRD), ATR, scanning electron microscopy and transmission electron microscopy analytical techniques. Notably, XRD analysis reveals a significant interaction between the starch chains and Mt through hydrogen bonding, indicative of starch and glycerol intercalation within the nanoclay gallery—a phenomenon further corroborated by IR spectra analysis. The nanoclay‐infused starch/glycerol composite film exhibits a noteworthy 2.22‐fold increase in water vapor permeability compared to clay free film, attributed to the formation of a convoluted diffusion path indicating the enhancement of the barrier performance of starch‐based films. Comparative evaluations against earlier studies are undertaken to elucidate the advancements in barrier properties, subsequently elucidating the underlying mechanisms through analytical interpretations. From the release study, the release of Fe2+ from the film with clay was observed to be more prolonged compared to a film without clay. As a result, the Montmorillonite clay–polymer composite film was selected for coating rice seeds using the dip‐coating method. [ABSTRACT FROM AUTHOR]

The V-defect is a naturally occurring inverted hexagonal pyramid structure that has been studied in GaN and InGaN growth since the 1990s. Strategic use of V-defects in pre-quantum well superlattices or equivalent preparation layers has enabled record breaking efficiencies for green, yellow, and red InGaN light emitting diodes (LEDs) utilizing lateral injection of holes through the semi-polar sidewalls of the V-defects. In this article, we use advanced characterization techniques such as scattering contrast transmission electron microscopy, high angle annular dark field scanning transmission electron microscopy, x-ray fluorescence maps, and atom probe tomography to study the active region compositions, V-defect formation, and V-defect structure in green and red LEDs grown on (0001) patterned sapphire and (111) Si substrates. We identify two distinct types of V-defects. The "large" V-defects are those that form in the pre-well superlattice and promote hole injection, usually nucleating on mixed (Burgers vector b = ± a ± c) character threading dislocations. In addition, "small" V-defects often form in the multi-quantum well region and are believed to be deleterious to high-efficiency LEDs by providing non-radiative pathways. The small V-defects are often associated with basal plane stacking faults or stacking fault boxes. Furthermore, we show through scattering contrast transmission electron microscopy that during V-defect filling, the threading dislocation, which runs up the center of the V-defect, will "bend" onto one of the six { 10 1 ¯ 1 } semi-polar planes. This result is essential to understanding non-radiative recombination in V-defect engineered LEDs. [ABSTRACT FROM AUTHOR]

Brominated activated carbon (AC/Br2) powder was used as a filler in poly(vinyl chloride) (PVC) to prepare PVC‐based composite films by hot pressing. The AC/Br2 filler was obtained by liquid phase bromination and contained both oxygen and bromine. In comparison with the unmodified AC, the AC/Br2 was subjected to thermogravimetric analysis in air and argon and temperature‐programmed desorption mass spectrometry in vacuum, which identified carbon‐oxygen and bromine groups and showed the comparable thermal stability of AC/Br2 and AC. XPS shows the predominance of phenolic groups among the carbon‐oxygen groups. Scanning electron microscopy and transmission electron microscopy showed preserved morphology and microstructure, while N2 adsorption showed a microporosity decrease after bromination. FTIR analysis suggested non‐chemical interactions between PVC and AC/Br2. As the AC/Br2 content in the PVC‐based composite films increases from 0.2 to 30 wt %, the electromagnetic radiation (EMR) reflection at Ka‐band microwave frequencies increases. To reduce the EMR reflection, the proposed composite films should contain a maximum of 0.2 wt % AC/Br2. The results indicate that the microwave properties of PVC‐based composite films can be tuned by adjusting the AC/Br2 content. [ABSTRACT FROM AUTHOR]