Electron Image Analysis Research Articles

Antagonistic actions of Paucibacter aquatile B51 and its lasso peptide paucinodin toward cyanobacterial bloom-forming Microcystis aeruginosa PCC7806.

Superior antagonistic activity against axenic Microcystis aeruginosa PCC7806 was observed with Paucibacter sp. B51 isolated from cyanobacterial bloom samples among 43 tested freshwater bacterial species. Complete genome sequencing, analyzing average nucleotide identity and digital DNA-DNA hybridization, designated the B51 strain as Paucibacter aquatile. Electron and fluorescence microscopic image analyses revealed the presence of the B51 strain in the vicinity of M. aeruginosa cells, which might provoke direct inhibition of the photosynthetic activity of the PCC7806 cells, leading to perturbation of cellular metabolisms and consequent cell death. Our speculation was supported by the findings that growth failure of the PCC7806 cells led to low pH conditions with fewer chlorophylls and down-regulation of photosystem genes (e.g., psbD and psaB) during their 48-h co-culture condition. Interestingly, the concentrated ethyl acetate extracts obtained from B51-grown supernatant exhibited a growth-inhibitory effect on PCC7806. The physical separation of both strains by a filter system led to no inhibitory activity of the B51 cells, suggesting that contact-mediated anti-cyanobacterial compounds might also be responsible for hampering the growth of the PCC7806 cells. Bioinformatic tools identified 12 gene clusters that possibly produce secondary metabolites, including a class II lasso peptide in the B51 genome. Further chemical analysis demonstrated anti-cyanobacterial activity from fractionated samples having a rubrivinodin-like lasso peptide, named paucinodin. Taken together, both contact-mediated inhibition of photosynthesis and the lasso peptide secretion of the B51 strain are responsible for the anti-cyanobacterial activity of P. aquatile B51.

Method for the Analysis of Respirable Airborne Particulates on Filter Using the Mineral Liberation Analyser

In recent years, the Mineral Liberation Analyser (MLA) has played a pivotal role in analysing respirable and inhalable ambient air samples collected on filters from both underground coal and metalliferous mines. Leveraging backscattered electron (BSE) image analysis and X-ray mineral identification, the MLA offers automated quantitative mineral characterization. The escalating prevalence and severity of mine dust lung diseases, particularly among young miners, have reignited interest in comprehensively understanding the dust’s characterization, encompassing mineralogy, particle size, and shape. Merely measuring total respirable dust exposure and its duration based on gravimetrically determined weight is no longer deemed sufficient in addressing the evolving landscape of occupational health challenges in mining environments. Since the publication of previous studies, efforts have been dedicated to refining the Mineral Liberation Analyser (MLA) methodology for respirable dust sampling. This refinement, discussed in detail in this paper, encompasses various enhancements, such as the implementation of data checks to identify carbon contamination, backscattered electron (BSE) drift, and the misclassification of X-ray spectra. Additionally, an examination of sampling efficiency led to the exploration of using smaller samples as an alternative to the time-intensive analysis of entire filters. Furthermore, this paper presents a reanalysis of paired filter sample sets previously reported using the Sarver Group Methodology. These samples are subjected to analysis using the Mineral Liberation Analyser, providing a more detailed illustration of the outputs derived from the updated methodology and compared to previously published MLA data.

The Effect of HPGR and Conventional Crushing on the Extent of Micro-Cracks, Milling Energy Requirements and the Degree of Liberation: A Case Study of UG2 Platinum Ore

Comparative high pressure grinding rolls (HPGR) and cone crusher pilot-scale tests were conducted using Upper Group 2 (UG2) platinum-bearing ore in order to determine the impact of micro-cracks in HPGR products toward energy requirements in ball mills and the degree of liberation. The ball mill was fed with HPGR and cone crusher products of similar particle size distributions (PSDs). Qualitative analysis of the degree of micro-cracking on the HPGR and cone crusher products performed using scanning electron microscope (SEM) and image analysis software showed that an HPGR product had more micro-cracks than the equivalent cone crusher product. Milling energy requirements were evaluated using size-specific energy consumption indices calculated based on three grind sizes of 300 µm, 150 µm and 75 µm. The effect of residual micro-cracks in the products of HPGR and cone crusher on the milling size-specific energy requirement is inconclusive. The kinetic parameter k in the cumulative rate kinetic model for ball milling cone crusher products and for ball milling HPGR products were similar. Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN) was used to determine the degree of liberation of various mineral phases in the mill products. At a coarser grind size (P80 of 300 µm), the sulfides in the mill products pre-crushed using the cone crusher have consistently poorer liberation than in the equivalent HPGR pre-crushed sample. However, at a finer grind size (P80 of 75 µm), the sulfides in the mill products pre-crushed using the cone crusher and using an HPGR showed similar liberation.

Corrosion Behaviors’ Investigation of Carbide Coatings Developed for Sulphuric Acid Recovery Systems

In this study, corrosion resistance of cobalt and nickel, which are known to have high corrosion resistance, reinforced tungsten carbide coatings applied to low carbon stainless steel material surfaces to reduce corrosion-induced losses in sulphuric acid recovery systems were investigated. During the recovery of sulphuric acid, aggressive sulphur systems in the baths cause the metal surface to dissolve and therefore a high amount of material loss occurs. In order to minimize corrosion induced material loss, 316 L stainless steel surfaces were coated with an interlayer of 95% nickel and 5% aluminium alloy, and then tungsten carbide coatings were synthesized on the surfaces of substrate materials reinforced with 13% cobalt and 13% nickel, respectively by thermal spraying method to further reduce the corrosion rate. Characterization of the produced coatings were carried out by X-ray diffraction (XRD), scanning electron microscope (SEM), optical microscope, image analyzer, and surface roughness device. The standard potentiodynamic polarization characteristics of the coatings for 1M H2SO4 solution at room temperature were investigated with a potentiostat/galvanostat device. As the obtained results, nickel reinforced tungsten carbide coatings with nickel aluminium interlayer showed the highest corrosion resistance against sulfuric acid environment with 0,41 mm/year corrosion rate. As a result of the article, the corrosion resistance of 316L stainless steels in sulfuric acid systems was improved by 5.02 and 3.15 times, respectively.

Effect of low-calcium and high-magnesium ferronickel slag on the microstructure and micromechanical properties of alkali-activated blended ground granulated blast furnace slag

In recent years, low-calcium and high-magnesium ferronickel slag (FNS) has been gradually used in the preparation of alkali-activated cements (AACs). An in-depth exploration of the microstructural characteristics is crucial for a thorough understanding and enhancement of the macroscopic behaviors of AACs. In this study, the microstructural composition and micromechanical properties of the alkali-activated ground granulated blast furnace slag (GGBS)-FNS cements (AASF) prepared with sodium silicate and sodium hydroxide as alkali activators were quantitatively studied. Backscattered electron image analysis (BSE-IA) and nanoindentation were selected to reveal the micromechanical properties of different phases in FNS particles and AASF pastes. The results show that the elastic modulus of sodium aluminosilicate hydrate (N-A-S-H) in alkali-activated FNS cement is about 17 GPa, which is similar to that of the gel phase in alkali-activated fly ash cement (AAFA) and alkali-activated metakaolin cement (AAMK), confirming that the micromechanical property of N-A-S-H gel is independent of the kind of precursor materials. The Ca/Si and Al/Si of the hydration products in AASF gradually decline as FNS is incorporated, whereas the Mg/Al steadily rises, increasing the elastic modulus of the inner hydration product (IP) phase in AASF. The reaction degree of GGBS is higher in the sodium silicate-activated AASF system, while more N-A-S-H gels are formed in the sodium hydroxide-activated AASF system. The incorporation of FNS is conducive to improving the reaction degree of GGBS, resulting in the increase of calcium silicoaluminate hydrate (C-A-S-H) content and a significant decrease in IP content in AASF.

Quantitative 3D Characterization of Functionally Relevant Parameters in Heavy-Oxide-Supported 4d Metal Nanocatalysts.

Accurate 3D nanometrology of catalysts with small nanometer-sized particles of light 3d or 4d metals supported on high-atomic-number oxides is crucial for understanding their functionality. However, performing quantitative 3D electron tomography analysis on systems involving metals like Pd, Ru, or Rh supported on heavy oxides (e.g., CeO2) poses significant challenges. The low atomic number (Z) of the metal complicates discrimination, especially for very small nanoparticles (1-3 nm). Conventional reconstruction methods successful for catalysts with 5d metals (e.g., Au, Pt, or Ir) fail to detect 4d metal particles in electron tomography reconstructions, as their contrasts cannot be effectively separated from those of the underlying support crystallites. To address this complex 3D characterization challenge, we have developed a full deep learning (DL) pipeline that combines multiple neural networks, each one optimized for a specific image-processing task. In particular, single-image super-resolution (SR) techniques are used to intelligently denoise and enhance the quality of the tomographic tilt series. U-net generative adversarial network algorithms are employed for image restoration and correcting alignment-related artifacts in the tilt series. Finally, semantic segmentation, utilizing a U-net-based convolutional neural network, splits the 3D volumes into their components (metal and support). This approach enables the visualization of subnanometer-sized 4d metal particles and allows for the quantitative extraction of catalytically relevant structural information, such as particle size, sphericity, and truncation, from compressed sensing electron tomography volume reconstructions. We demonstrate the potential of this approach by characterizing nanoparticles of a metal widely used in catalysis, Pd (Z = 46), supported on CeO2, a very high density (7.22 g/cm3) oxide involving a quite high-atomic-number element, Ce (Z = 58).

Enhanced hydrogen sorption properties of uniformly dispersed Pd-decorated three-dimensional (3D) Mg@Pd architecture

This study demonstrates the hydrogen sorption improvement of Mg through the three-dimensional decoration of a noble catalyst. An Mg@Pd composite was synthesized by decorating Pd nanoparticles onto the Mg matrix via a facile solid-gas reduction method. Electron tomography analysis confirms the formation of a three-dimensional (3D) architecture of the Mg@Pd particulate composite. The Mg@Pd composite shows excellent hydrogenation/dehydrogenation kinetics even at low temperatures as compared to a catalyst-free Mg sample. Moreover, the hydrogenated Mg@Pd composite can desorb hydrogen at as low as 246 °C that is 87 °C lower than that of the pure MgH2. Hydrogenation of the Mg@Pd composite leads to the development of a multiphase system consisted of PdH0.706, MgPd and MgH2 whereas dehydrogenation occurred via two simultaneous desorption reactions results in Mg6Pd and Mg phases. The uniform dispersion of Pd nanoparticles on the surface of the 3D Mg matrix has provided with fast catalytic interfaces via the hydrogen “spillover” mechanism while the concomitant hydrogen diffusion processes are enhanced by the “hydrogen pump” effect of PdH0.706/MgPd interfaces. Furthermore, the low temperature hydrogen sorption performances of the Mg@Pd composite can be attributed to the interphase reversibility between MgPd and Mg6Pd leading to the thermodynamic destabilization of MgH2. This study suggests that strategically new approaches can govern significant improvements in hydrogen storage properties of Mg-based systems.

Early-age shrinkage behavior of cement-fly ash paste under wind speeds: A study using BSE-IA and MIP techniques

While laboratory studies have shown that fly ash (FA) can reduce shrinkage in cement-based materials in the absence of wind, its impact on cement-based materials under wind speed conditions has not been extensively studied. This research investigates the influence of FA on the early-age shrinkage of cement paste under various wind speeds. The corresponding changes in pore structure were tested using mercury intrusion porosimetry (MIP) and backscattered electron image analysis (BSE-IA). The results show that under wind speed conditions, FA is not effective in reducing early-age shrinkage of cement paste. In fact, high levels of FA content can increase shrinkage values under wind speed conditions. Both wind speed and FA increase water evaporation, but they have different impact times. Although both wind speed and FA decrease mesopore content below 50 nm and increase water evaporation, they have opposite effects on early-age shrinkage. This suggests that mesopore content and water evaporation alone cannot fully characterize the change trend of early drying shrinkage. The two-factor parameter rs, which combines water evaporation and MIP-based pore size distribution, can effectively characterize drying shrinkage trends under the combined effects of wind speed and FA. BSE-IA can intuitively characterize pore size distribution above 200 nm, while the results of MIP underestimate the distribution of large capillary pores. Therefore, the current rs obtained based on MIP may be smaller than the actual value. With the advancement of testing technology in the future, rs can be further optimized.

Grain coarsening during liquid phase sintering of zircon–glass composites

This study examined zircon grain growth during isothermal sintering of a zircon–glass composite with a zircon volume fraction of 0.525 zircon volume/solids volume, at a temperature of 1200°C, with different residence times, ranging from 5min to 1500min. Scanning electron microscopy and image analysis were used to determine zircon grain size and number in the fired test specimens. The residual glass composition was determined by energy dispersive X-ray spectroscopy. For each firing condition, the grain size number distribution was fitted to a lognormal function and to a Weibull function. In every case, the lognormal distribution described the results better. Grain size grew and distribution width decreased with sintering time in accordance with non-steady-state grain growth models. At high sintering times, the variation of average grain diameter and grain number density per unit solids cross-section fitted well to steady-state growth models. Moreover, when grain size distribution was scaled by the average size, it was practically time independent. In contrast, scaled grain distribution width was much wider than that predicted by these models. A model was developed that satisfactorily predicts zircon grain evanescence throughout the sintering process.

A study on the collapse characteristics of loess based on energy spectrum superposition method

Mineral types form the basis for studying the structural stability of loess, and identifying mineral types at the microscopic scale has always been a difficult task. Identifying mineral types at the microscopic scale is very helpful in understanding the differential role that different minerals play in the structural stability of loess, and it can also clarify the specific mineral changes that occur during the process of humidification and dehumidification. Using an innovative energy spectrum superposition method, this article combines backscattered electron imaging and X-ray energy spectrum analysis results to achieve direct identification of the eight main minerals in loess, including quartz, illite, and chlorite, within SEM images. The mineral identification results provide a basis for statistical analysis of mineral water sensitivity and morphological changes under wetting conditions. The results demonstrate that chlorite and hematite, which account for no more than 23% of the loess composition, play a crucial role in binding. Furthermore, these minerals exhibit significant hydrolysis phenomena. Particularly, the intense decomposition of chlorite leads to the displacement of non-binding quartz and feldspar particles, thereby altering the pore structure of loess. These findings are of great significance in understanding the multi-level collapsibility of loess.

Effect of chloride concentration on the corrosion resistance of pure Zn metal in a 0.0626 M H2SO4 solution

Abstract The aftermath of Cl− anion concentration reactions on the corrosion resistance of pure Zn metal in 0.0625 M H2SO4 was examined by potentiodynamic polarization, optical representations, scanning electron image analysis, energy dispersive X-ray (EDX) spectroscopy, open-circuit potential analysis, X-ray diffractometry, weight loss method and X-ray fluorescence. The results show that the degradation of Zn increased with an increase in the chloride concentration from 4.089 and 0.218 mm/year to 10.085 and 4.015 mm/year (polarization and weight loss). The corrosion potential at 0.0625 M H2SO4 to 0.0625 M H2SO4/0.5% NaCl concentration displayed minimal variation (−1.535 to −1.519 V), whereas a significant shift was observed for the plots at 0.0625 M H2SO4/1% NaCl and 0.0625 M H2SO4/2% NaCl (−1.384 and −0.932 V). The weight loss plot at all Cl− anion concentrations displayed an ordered decrease in the corrosion rate analogous to exposure times. The scanning electron microscopic images of Zn in 0.0625 M H2SO4/2% NaCl solution showed significant deterioration and corrosion pits. The image at 0.0625 M H2SO4 solution revealed limited localized and general surface deterioration, while the corresponding EDX data depict the presence of S. The Zn open-circuit potential plot from a 0.0625 M H2SO4 solution was relatively electropositive compared to the plot from a 0.0625 M H2SO4/2% NaCl solution. Both plots exhibited limited reactive-inert transition properties and attained relative thermodynamic equilibrium after 600 s of exposure with final corrosion potentials of −0.91 and −0.97 V at 7,200 s. Zn was the only crystallographic phase identified on its surface before corrosion, whereas ZnS, ZnFes, ZnMnS, ZnMnFeS, and ZnMg4 corrosion products were identified after corrosion.

PickYOLO: Fast deep learning particle detector for annotation of cryo electron tomograms

Particle localization (picking) in digital tomograms is a laborious and time-intensive step in cryogenic electron tomography (cryoET) analysis often requiring considerable user involvement, thus becoming a bottleneck for automated cryoET subtomogram averaging (STA) pipelines. In this paper, we introduce a deep learning framework called PickYOLO to tackle this problem. PickYOLO is a super-fast, universal particle detector based on the deep-learning real-time object recognition system YOLO (You Only Look Once), and tested on single particles, filamentous structures, and membrane-embedded particles. After training with the centre coordinates of a few hundred representative particles, the network automatically detects additional particles with high yield and reliability at a rate of 0.24–3.75 s per tomogram. PickYOLO can automatically detect number of particles comparable to those manually selected by experienced microscopists. This makes PickYOLO a valuable tool to substantially reduce the time and manual effort needed to analyse cryoET data for STA, greatly aiding in high-resolution cryoET structure determination.

Mechanical properties and durability of geopolymer concrete based on fly ash and coal gangue under different dosage and particle size of nano silica

In order to test the engineering applicability of mixed base geopolymer concrete and analyze the modification effect of nano additive systematically, nano silica (NS) was used to reinforce fly ash and coal gangue based geopolymer concrete (FACGGC). The mechanical properties and environmental suitability of the specimens were tested to analyze the effects of different dosing amounts (0–1.5 wt%) and particle sizes (20 and 100 nm) of nano silica on FACGGC. The results showed that the appropriate amount of NS could significantly improve the performance of FACGGC, excessive NS had significant negative impact. For different performance tests, the optimal dosage of NS was different. Under the same dosage, the effect of smaller particle size NS (20 nm) on the mechanical properties and water absorption of NS-FACGGC was better than larger particle size NS (100 nm), while the effect of larger particle size NS on resistance to sulfate attack was better. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and image analysis showed that NS with smaller particle sizes had a higher filling effect and were more likely to serve as nucleation sites, but when NS was over doped, the agglomeration effect of NS with smaller particle sizes was more significant.

Types of cell culture inserts affect cell crosstalk between co-cultured macrophages and adipocytes

Cell culture inserts offer an in vivo-like microenvironment to investigate cell-cell interactions between co-cultivated cells. However, it is unclear if types of inserts affect cell crosstalk. Here, we developed an environment-friendly cell culture insert, XL-insert, which can reduce plastic waste with lower cost. We compared XL insert with two types of commercial disposable culture inserts, Koken® insert with atelocollagen membrane (Col-inserts) and Falcon® inserts with plastic membrane (PET-inserts) on cell-cell interactions in co-cultivated THP-1 macrophages and OP9 adipocytes. Scanning electron microscope, immunoassay and imaging analysis showed that among three types of inserts, XL-inserts allowed cytokines from co-cultivated macrophages and adipocytes to diffuse freely and offered preferable in vivo-like microenvironment for cell-cell interactions. PET-inserts showed limitations for intercellular communication due to some pores being blocked by somas on the membrane that caused much lower permeability for cytokines passing through. Col-inserts blocked large sized cytokines but allowed small sized molecules to permeate resulting in improved lipid accumulation and adiponectin secretion in OP9 adipocytes. Taken together, our data demonstrated that membrane type and pore size on the membrane affect the cross-talk between co-cultivated cells very differently. Some previous co-culture studies might have different results if the inserts were changed.

Optimisation of the Flame Spheroidisation Process for the Rapid Manufacture of Fe3O4-Based Porous and Dense Microspheres

The rapid, single-stage, flame-spheroidisation process, as applied to varying Fe3O4:CaCO3 powder combinations, provides for the rapid production of a mixture of dense and porous ferromagnetic microspheres with homogeneous composition, high levels of interconnected porosity and microsphere size control. This study describes the production of dense (35-80 µm) and highly porous (125-180 µm) Ca2Fe2O5 ferromagnetic microspheres. Correlated backscattered electron imaging and mineral liberation analysis investigations provide insight into the microsphere formation mechanisms, as a function of Fe3O4/porogen mass ratios and gas flow settings. Optimised conditions for the processing of highly homogeneous Ca2Fe2O5 porous and dense microspheres are identified. Induction heating studies of the materials produced delivered a controlled temperature increase to 43.7 °C, indicating that these flame-spheroidised Ca2Fe2O5 ferromagnetic microspheres could be highly promising candidates for magnetic induced hyperthermia and other biomedical applications.

Influence of recycled concrete aggregate enhancement methods on the change of microstructure of ITZs in recycled aggregate concrete

Recycled concrete aggregate (RCA) enhancement is an important method to improve the performance of recycled aggregate concrete (RAC). However, the quantitative studies on the change of microstructure of interfacial transition zones (ITZs) were few and far, especially after enhancement of RCA with different methods. This paper investigated the influence of carbonation enhancement (carbonation time, soaking in CH saturated solution and then carbonation) and chemical enhancement (respectively soaking in Na2SiO3 saturated solution and cement-silica fume (CEM-SF) slurries) of RCA on the change of microstructure of ITZs (including the ITZ between old aggregate-new paste (ITZ1) and ITZ between old paste-new paste (ITZ2)) in RAC. The porosity, the un-hydrated cement particles (UH) content, the volume fraction of hydration products (VFHP) in ITZs and the width of ITZs were obtained by backscattered electron imaging analysis (BSE-IA) and energy dispersive spectrometer (EDS) analysis. Results showed that the carbonation enhancement of RCA could not effectively strengthen ITZ1. However, soaking RCA in Na2SiO3 saturated solution and CEM-SF slurries could decrease the porosity and the UH content, develop the VFHP, and reduce the width of ITZ1, then strengthening ITZ1. Both carbonation and chemical enhancement could take obviously improvement on ITZ2. Additional calcium sources could be added to RCA by soaking in CH saturated solution, improving the effect of carbonation enhancement of RCA. Soaking in CEM-SF slurries had a better improvement effect on ITZs. After RCA was soaked in CEM-SF slurries, the porosity in ITZ1 and ITZ2 decreased by 36.8% and 44.0%, the UH content of ITZ1 and ITZ2 decreased by 22.6% and 53.6%, the VFHP of ITZ1 and ITZ2 increased by 22.6% and 20.9%, and the width of ITZ1 and ITZ2 decreased by 42.9% and 50%. EDS analysis showed that the Ca/Si atomic ratio of ITZs was reduced after RCA enhancement, which generated more hydration products and then decreased the porosity and the width of ITZs.

Dynamic Precipitation During Forging of a γ–γ′ Nickel-Based Superalloy

Hot compression and creep tests under different conditions were performed on a typical γ–γ′ polycrystalline nickel base superalloy below the γ′-phase solvus temperature, to shed light on the mechanisms of γ′ precipitation during deformation and the driving forces behind these mechanisms. Scanning Electron Microscopy (SEM) and image analysis were employed to characterize the different populations of γ′ precipitates and their evolutions. The γ′-phase area fractions observed after hot compression are systematically higher than the fraction prior to deformation within the investigated range of thermomechanical conditions. Two new populations of precipitates formed during deformation are identified and characterized. These are interpreted to result from a dynamic precipitation process, the hypothesis of their formation during the quenching step being very unlikely with regards to their size and amount. The fraction of γ′-phase produced during deformation increases with increasing deformation magnitude, decreasing deformation temperature and for slower strain rates. Finally, a scenario for dynamic γ′ precipitate nucleation and growth is proposed to explain the experimental observations and the influence of dislocation density.

Effect of cold-rolling deformation and rare earth yttrium on microstructure and texture of oriented silicon steel

Abstract In order to study the effect of cold-rolling deformation and rare earth Y on the microstructure and texture of 3.0% Si-oriented silicon steel, the microstructure and texture of cold-rolled oriented silicon steel with 60, 72, and 86% deformation are analyzed using electron backscatter diffraction and image analysis software. The experimental results show that the deformation band becomes narrower and the distribution of shear bands becomes denser with increasing cold-rolling deformation. Compared to the Y-free steel, cold-rolled sheet containing rare earth Y has greater shear bands. The pinning effect of rare earth Y hinders the dislocation movement, which leads to the increase of kernel average misorientation value and shear bands. With the increase of cold-rolling deformation, the texture concentrates on α and λ. This is mainly due to the change from {100} 〈001〉 to {001} 〈110〉, intensifying λ texture, and the change from {111} 〈112〉 to {111} 〈110〉, thus strengthening the α texture. The texture strength of cold-rolled sheets can be decreased by rare earth Y. But the γ texture strength in cold-rolled sheets containing Y is significantly higher than in those without Y. The γ texture strength can reach up to 7.3, and the strong points are mainly {111} 〈112〉. This is because the number of inclusions in steel increases with the addition of rare earth Y. In the process of grain nucleation, the {111} oriented grains nucleate heterogeneously on the inclusions. It forms a large number of {111} oriented grains and improves the γ texture strength.

Quantification of plasmodesmata frequency under three-dimensional view using focused ion beam-scanning electron microscopy and image analysis

The quantitative study of plasmodesmata (PD) frequency is routine in plant science for providing information on the potential of intercellular transportation. Here, we report quantification of plasmodesmatal frequency in virus-infected tobacco vascular tissues using serial sectioning and image analysis. The image datasets were collected by focused ion beam-scanning electron microscopy (FIB-SEM), and the measurements of plasmodesmatal frequency were performed after image analysis with commercial computational programs. With a 5-nm step size (less than half the diameter of PD) during FIB sectioning, exhaustive PD sampling was performed in regions of interest. Segmentation of cell wall (CW) and PD from the background densities was performed manually, and PD were assigned automatically to individual CW interfaces by image analysis and then quantified. The PD quantification results were used to compare the plamodesmatal frequencies among different CW interfaces of individual cells and the average frequencies among different cell types were calculated. CWs lacking PD distribution were found in several cellular types, and the PD frequency were used to determine the possible pathways of PD-based symplasmic transportation. The method enables imaging of samples of several cells containing multiple CW interfaces and minimizes PD omission during sectioning and imaging.

Multigram-Scale Production of Hybrid Au-Si Nanomaterial by Laser Ablation in Liquid (LAL) for Temperature-Feedback Optical Nanosensing, Light-to-Heat Conversion, and Anticounterfeit Labeling.

Recent progress in hybrid optical nanomaterials composed of dissimilar constituents permitted an improvement in the performance and functionality of novel devices developed for optoelectronics, catalysis, medical diagnostics, and sensing. However, the rational combination of contrasting materials such as noble metals and semiconductors within individual hybrid nanostructures via a ready-to-use and lithography-free fabrication approach is still a challenge. Here, we report on a two-step synthesis of hybrid Au-Si microspheres generated by laser ablation of silicon in isopropanol followed by laser irradiation of the produced Si nanoparticles in the presence of HAuCl4. Thermal reduction of [AuCl4]- species to a metallic gold phase, along with its subsequent mixing with silicon under laser irradiation, creates a nanostructured material with a unique composition and morphology, as revealed by electron microscopy, tomography, and elemental analysis. A combination of basic plasmonic and nanophotonic materials such as gold and silicon within a single microsphere allows for efficient light-to-heat conversion, as well as single-particle SERS sensing with temperature-feedback modality and expanded functionality. Moreover, the characteristic Raman signal and hot-electron-induced nonlinear photoluminescence coexisting within the novel Au-Si hybrids, as well as the commonly criticized randomness of the nanomaterials prepared by laser ablation in liquid, were proved to be useful for the realization of anticounterfeiting labels based on a physically unclonable function approach.