Distribution Of Elements Research Articles

Assessment of rare earth elements variations in five water systems in Beijing: Distribution, geochemical features, and fractionation patterns

This study investigates the distribution of rare earth elements (REEs) within the Beijing water system, specifically examining the Yongding, Chaobai, Beiyun, Jiyun, and Daqing rivers. Results indicate that the Beiyun River exhibits the highest REE concentrations, ranging from 35.95 to 59.78 μg/mL, while the Daqing River shows the lowest concentrations, ranging from 15.79 to 17.48 μg/mL. LREEs (La to Nd) predominate with a total concentration of 23.501 μg/mL, leading to a notable LREE/HREE ratio of 7.901. Positive Ce anomalies (0.70–1.11) and strong positive Eu anomalies (1.38–2.49) were observed. The study suggests that the Beijing water system's REEs may originate from geological and anthropogenic sources, such as mining and industrial activities in neighboring regions, including Inner Mongolia. These findings underscore the importance of ongoing monitoring and effective water management strategies to address REE-related environmental concerns.

Recovery of Ni-Co-Mn Oxides from End-of-Life Lithium-Ion Batteries for the Application of a Negative Temperature Coefficient Sensor

This study demonstrates the current advancements in battery management systems (BMSs), emphasizing the need for precise temperature monitoring within battery packs to enhance safety and performance through efficient thermal management. The increased demand for lithium-ion batteries (LIBs) has driven the development of temperature sensors with improved accuracy and stability. In particular, Ni-Co-Mn-based spinel oxides are commonly used due to their stable negative temperature coefficient (NTC) behavior. However, challenges arise in manufacturing due to the high cost and uncertain supply of critical cathode components (e.g., Co, Ni, and Mn) for LIBs. This research focuses on developing spinel-type (Ni0.6Co0.4Mn2)O4 using recycled Ni-Co-Mn oxides obtained from end-of-life (EOL) LIBs, demonstrating temperature resistance behavior suitable for temperature sensing. The oxides are prepared through hydrometallurgy, oxalate synthesis, and post-heat treatment. Successful integration into spinel-type NTC thermistors suggests broader applications in various industrial fields. A systematic investigation into the synthesis and characterization of recovered Ni-Co-Mn oxides from EOL LIB cathode materials (Li(Ni0.33Co0.33Mn0.33)O2) is presented for NTC thermistor application. Thermogravimetric analysis-derivative thermogravimetry (TGA-DTG) identifies the optimal post-heat treatment temperature. The X-ray diffraction (XRD) patterns confirm a cubic spinel structure of the Ni-Co-Mn oxides, supported by scanning electron microscope (SEM) images showing a uniform microstructure. Also, energy dispersive X-ray spectroscopy (EDS) mapping confirms homogeneous element distribution. Recovered oxide pellets from the sintering process exhibit a single spinel structure, with X-ray photoelectron spectroscopy (XPS) analysis revealing changes in the valence states for Ni and Mn. Resistivity measurements demonstrate semiconductive behavior, which shows a B value (3376.92 K) suitable for NTC thermistor applications. This study contributes valuable insights to black powder recycling from EOL LIBs and its potential in temperature-sensitive electronic devices.

Rapid Freezing and Cryo-SEM-EDS Imaging of Foraminifera (Unicellular Eukaryotes) Using a Conductive Viscous Cryogenic Glue.

Spatial distribution of water-soluble molecules and ions in living organisms is still challenging to assess. Energy-dispersive X-ray spectroscopy (EDS) via cryogenic scanning electron microscopy (cryo-SEM) is one of the promising methods to study them without loss of dissolved contents. High-resolution cryo-SEM-EDS has challenges in sample preparation, including cross-section exposure and sample drift/charging due to insulative surrounding water. The former becomes problematic for large and inseparable organisms, such as benthic foraminifera, a unicellular eukaryote playing significant roles in marine ecosystems, which often exceed the size limit for the most reliable high-pressure freezing. Here we show graphite oxide dispersed in sucrose solution as a good glue to freeze, expose cross-section by cryo-ultramicrotome, and analyze elemental distribution owing to the glue's high viscosity, adhesion force, and electron conductivity. To demonstrate the effectiveness and applicability of the glue for cryo-SEM-EDS, deep-sea foraminifer Uvigerina akitaensis was sampled during a cruise and plunge frozen directly on the research vessel, where the liquid nitrogen supply is limited. The microstructures were preserved as faithfully in cryo-SEM images as those with the conventional resin-substituted transmission electron micrograph. We found elements colocalized within the cytoplasm originating from water-soluble compounds that can be lost with conventional dehydrative fixation.

Distribution and bioaccumulation of trace elements in two Cyprinidae fish species in the Indus river, Pakistan, including the impact of hydraulic structure on macroinvertebrates' biodiversity

The concentration of trace elements (chromium, lead, zinc, copper, manganese, and iron) was determined in water, sediment and tissues of two Cyprinidae fish species - Labeo rohita and Tor putitora – collected from the eight sampling stations of Indus River in 2022 for four successive seasons (autumn, winter, spring, summer), and also study the present condition of macroinvertebrates after the construction of hydraulic structure. The obtained results of trace element concentrations in the Indus River were higher than the acceptable drinking water standards by WHO. The nitrate concentration ranges from 5.2 to 59.6 mg l−1, turbidity ranges from 3.00 to 63.9 NTU, total suspended solids and ammonium ions are below the detection limit (<0.05). In the liver, highest dry wt trace elements (μg/g) such as Cr (4.32), Pb (7.07), Zn (58.26), Cu (8.38), Mn (50.27), and Fe (83.9) for the Labeo rohita; and Tor Putitora has significantly greater accumulated concentration (Cr, Pb, Zn, Cu, Mn, Fe) in muscle and liver than did Labeo rohita species. Additionally, lower number of macroinvertebrates were recorded during the monsoonal season than pre-monsoon and post-monsoon. Local communities surrounded by polluted environments are more probably to consume more fish and expose them to higher concentrations of toxic trace elements (lead and copper). The findings also provide a basis for broader ecological management of the Indus River, which significantly influenced human beings and socioeconomic disasters, particularly in the local community.

Investigating the impact of insertion sequences and transposons in the genomes of the most significant phytopathogenic bacteria.

Genetic variability in phytopathogens is one of the main problems encountered for effective plant disease control. This fact may be related to the presence of transposable elements (TEs), but little is known about their role in host genomes. Here, we performed the most comprehensive analysis of insertion sequences (ISs) and transposons (Tns) in the genomes of the most important bacterial plant pathogens. A total of 35 692 ISs and 71 transposons were identified in 270 complete genomes. The level of pathogen-host specialization was found to be a significant determinant of the element distribution among the species. Some Tns were identified as carrying virulence factors, such as genes encoding effector proteins of the type III secretion system and resistance genes for the antimicrobial streptomycin. Evidence for IS-mediated ectopic recombination was identified in Xanthomonas genomes. Moreover, we found that IS elements tend to be inserted in regions near virulence and fitness genes, such ISs disrupting avirulence genes in X. oryzae genomes. In addition, transcriptome analysis under different stress conditions revealed differences in the expression of genes encoding transposases in the Ralstonia solanacearum, X. oryzae, and P. syringae species. Lastly, we also investigated the role of Tns in regulation via small noncoding regulatory RNAs and found these elements may target plant-cell transcriptional activators. Taken together, the results indicate that TEs may have a fundamental role in variability and virulence in plant pathogenic bacteria.

Submicronic-Scale Mechanochemical Characterization of Oxygen-Enriched Materials.

Conventional techniques that measure the concentration of light elements in metallic materials lack high-resolution performance due to their intrinsic limitation of sensitivity. In that context, scanning microwave microscopy has the potential to significantly enhance the quantification of element distribution due to its ability to perform a tomographic investigation of the sample. Scanning microwave microscopy associates the local electromagnetic measurement and the nanoscale resolution of an atomic force microscope. This technique allows the simultaneous characterization of oxygen concentration as well as local mechanical properties by microwave phase shift and amplitude signal, respectively. The technique was calibrated by comparison with nuclear reaction analysis and nanoindentation measurement. We demonstrated the reliability of the scanning microwave technique by studying thin oxygen-enriched layers on a Ti-6Al-4V alloy. This innovative approach opens novel possibilities for the indirect quantification of light chemical element diffusion in metallic materials. This technique is applicable to the control and optimization of industrial processes.

TiO2–SiO2 nanocomposite via a novel sol-gel method with the addition of an energy monitoring device: Synthesized, characterization and anti-bacterial applications

The present paper successfully employs a modified sol-gel method to synthesize TiO2–SiO2 nanocomposites. By incorporating a hygrometer and energy monitoring devices, we achieved real-time monitoring of the drying process and optimized temperature control. Energy consumption during the drying process was observed, revealing that higher temperatures result in shorter drying times. The lowest energy consumption was recorded at 80 °C, while the optimal temperature, obtained from the conversion of the optimization diagram, occurred at 77 °C. Characterization was performed using different tools such as XRD, FT-IR analysis, XPS, FE-SEM-EDS, and HRTEM to determine the size and distribution of elements, crystal structure, and chemical bonds. Furthermore, an anti-bacterial test was conducted, revealing that the nanocomposite exhibited superior antibacterial properties against Staphylococcus aureus and Escherichia coli. Meeting the required standards, the TiO2–SiO2 nanocomposite produced by this method shows the potential to create a cleaner and more efficient environment in medical and industrial applications.

Sintering densification behavior of nano-ITO powder with high oxygen vacancy induced via plasma stimulation

With the growing electronics display industry, indium tin oxide (ITO) powder plays a crucial role in target preparation. To enhance the sintering performance of ITO powder, a high-activity nano ITO powder was prepared using plasma spraying, and compared to a commercial powder. This study aimed to investigate the effects of different preparation methods on powder morphology, dispersibility, oxygen vacancy concentration, and the physical properties of powders on target density, surface morphology, grain size, element distribution, and solid solubility. The results indicate that the plasma spraying high-activity nano ITO powder exhibits better dispersibility, higher oxygen vacancy concentration, and a specific surface area of up to 88.39 m2/g compared to the commercial powder. Under normal pressure sintering conditions, plasma spraying nanoscale ITO powder exhibits higher sintering activity, leading to easier densification of ceramic targets with reduced porosity, more uniform surface grains, and significant stepped growth between surface grains. High-resolution transmission electron microscopy (HRTEM) analysis suggests that targets prepared with high-activity powder have greater tin solubility in indium oxide compared to traditional commercial ceramic targets. This article further explores the relationship between powder specific surface area, oxygen vacancy, and sintering activity, along with the formation mechanism of high oxygen vacancy.

Nanocrystalline Fe(Co)ZrMoBCu soft magnetic alloys: A transmission electron microscopy study of the microstructures

Nanocrystalline Fe81Zr7Mo2B9Cu1 and Fe40.5Co40.5Zr7Mo2B9Cu1 alloy ribbons were prepared by annealing the as-quenched amorphous alloys at their first exothermic peak temperature. The primary crystallization phases of Fe81Zr7Mo2B9Cu1 and Fe40.5Co40.5Zr7Mo2B9Cu1 consisted of nanoscale body-centered cubic α-Fe and α-FeCo grains, respectively. The microstructures and compositions were analyzed via transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM), and area maps were obtained through energy-dispersive spectroscopy (EDS). The addition of Co decreased the mean grain size (D) and broadened the grain-size distribution (σ). The effect of the addition of Co on the Cu clusters and element distribution was studied in detail. Scanning transmission electron spectroscopy combined with energy-dispersive spectroscopy revealed that both alloys contained Cu clusters; the Fe40.5Co40.5Zr7Mo2B9Cu1 alloy exhibited a Cu-cluster density similar to that of the Fe81Zr7Mo2B9Cu1 alloy. Both alloys contained relatively less Fe in their residual amorphous phases than in their nanocrystals, with the nanocrystals in Fe40.5Co40.5Zr7Mo2B9Cu1 containing less Co than in the residual amorphous phase. Fe40.5Co40.5Zr7Mo2B9Cu1 exhibited higher specific saturation magnetization (Ms), specific remanent magnetization (Mr) and larger coercivity (Hc) than Fe81Zr7Mo2B9Cu1.

Occurrence state and distribution characteristics of tungsten in Dabaoshan tungsten-bearing goethite

The phase composition and elemental distribution of the tungsten-bearing goethite in Dabaoshan, Guangdong Province, China, were explored through various analytical methods, aiming to reveal the occurrence state and embedding characteristics of critical metal W in the ore. X-ray fluorescence analysis (XRF), powder X-ray diffraction (powder XRD), and scanning electron microscopy and energy dispersive spectroscopy (SEM–EDS) results show that the grade of critical metal W is 1.35%, and its main minerals are tungsten-bearing goethite and quartz. Micro-area XRD and mineral liberation analyzer (MLA) results indicate that ferrotungsten ore ((W,Fe)(O,OH)3), the tungsten-bearing phase, was mainly present in the form of stripped and banded goethite. The valuable element distribution in major minerals was also quantitatively determined. Moreover, a possible mechanism for the evolution and formation of tungsten-bearing goethite weathering was discussed, and a combined flowsheet of beneficiation–metallurgical separation was proposed to provide a theoretical basis for the high-efficient recovery of critical metal W from tungsten-bearing goethite.

The Effect of Limestone Particle Size on Hardness of Polylactic Acid/Hydroxyapatite Composite

Limestone is a mineral that mainly contained calcium oxide. Limestone has been used in manufacture industries for decades. Many researchers utilized limestone as a material for hydroxyapatite. Hydroxyapatite is a biocompatible material for human body and it is a potential material to restore the damaging bone. However, the hardness of hydroxyapatite is low. In this research, hydroxyapatite made from limestone and disodium hydrogen phosphate dihydrate were mixed with polylactic acid. The limestone was added as a source of calcium and increased the hardness of the composite. Polylactic acid was added to increase the compatibility between the components. The limestone particles sizes effect was studied using limestone powder size of 56 μm, 100 μm, and 150 μm. The composite was prepared by weighting, pre-heating, mixing, heating and pressing of the ingredients. The mechanical characterization was carried out through Micro Vickers Hardness Test. The composition of the composite was analyzed using X-ray Fluorescence. The surface morphology, interface adhesion, and element distribution were observed using scanning electron microscope and energy dispersive spectroscopy. The calcium-phosphor ratio of the composite similar with the one in the human bone. The composite that contained the finer size of limestone powder has the highest hardness. The ratio of the calcium to phosphor is 1.63.

Cu/MgO-based resistive random access memory for neuromorphic applications

Resistive Random Access Memory (ReRAM) is considered to be a suitable candidate for future memories due to its low operating voltage, fast access speed, and the potential to be scaled down to nanometer range for ultra-high-density storage. In addition, its ability to retain multi-level resistance states makes it suitable for neuromorphic computing applications. In this paper, we report the resistive switching performance of Cu/MgO/Pt ReRAM. Repetitive resistive switching transitions with low switching voltages (around 1 V), 102 storage windows, and multi-level memory capabilities have been obtained. Biological synaptic plasticity behavior, such as long-duration potentiation/depression and paired-pulse facilitation, has been realized by the Cu/MgO/Pt ReRAM. The simulation of convolutional neural network for handwritten digit recognition is carried out to evaluate its potential application in neuromorphic systems. Finally, the conduction mechanism of the device is studied, and a resistive switching model based on Cu conducting filaments is proposed according to the dependence of I–V results on temperature and electrode size as well as the element distribution in the device. These findings indicate the potential of Cu/MgO/Pt device as high-performance nonvolatile memories and its utilization in future computer systems and neuromorphic computing.

Scallop shells as biosorbents for water remediation from heavy metals: Contributions and mechanism of shell components in the adsorption of cadmium from aqueous matrix

To ascertain their potential for heavy metal pollution remedy, we studied the adsorption mechanism of cadmium onto scallop shells and the interactions between the heavy metal and the shell matrix. Intact shells were used to investigate the uptake and diffusion of the metal contaminant onto the shell carbonatic layers, as well as to evaluate the distribution of major and trace elements in the matrix. LA-ICPMS measurements demonstrate that Cd is adsorbed on a very thin layer on the inner and outer surfaces of the shell. Structural and thermal analyses showed the presence of 9 wt.-% of a CdCO3 phase indicating that the adsorption is mainly a superficial process which involves different processes, including ion exchange of Ca by Cd. In addition, organic components of the shell could contribute to adsorption as highlighted by different metal uptake observed for shells with different colours. In particular, darker shells appeared to adsorb more contaminant than the white ones. The contribution of the organic shell components on the adsorption of heavy metals was also highlighted by the element bulk content which showed higher concentrations of different metals in the darker specimen. Raman spectroscopy allowed to identify the pigments as carotenoids, confirmed by XRD measurements which highlighted the presence of astaxanthin phases. The results presented here provide new insights into the Cd adsorption mechanism highlighting the important contribution given by the organic components present in the biogenic carbonate matrix. Furthermore, the high efficiency of Cd removal from water by scallop shells, supported by adsorption kinetic and isotherm studies, has been demonstrated.

Assessment of elemental chemistry, spatial distribution, and potential risks of road-deposited dusts in Sharjah, United Arab Emirates

Road dust is a major source of pollution in the environment, carrying different pollutants, including heavy metals and metalloids, from one location to another. This study assesses the concentrations of eight heavy metals and one metalloid (Zn, Pb, Mn, Fe, Cr, Cu, Cd, Ni, and As) in dust samples collected from sixty-eight streets of Sharjah, United Arab Emirates using ICP-OES, as well as investigates their effects on both the environment and humans. Mean concentrations of the elements in μg/g across the sites were 392 ± 46 (Zn), 68.28 ± 11.3 (Pb), 1437 ± 67 (Mn), 39,481 ± 4611 (Fe), 460 ± 31 (Cr), 150 ± 44 (Cu), 1.25 ± 0.65 (Cd), 856 ± 72 (Ni), and 0.97 ± 0.28 (As). The Cdeg and ERI calculated from the study were 54.79 and 573, respectively, suggesting varying pollution levels. The highest contributions were from Ni, Cd, Zn, Cu, Cr, and Pb, especially in areas with heavy traffic. The non-carcinogenic risk assessments were generally low for the three routes of exposure, except HQoral that was slightly higher for children. Similarly, none of the elements exhibited any carcinogenic risk except chromium. Overall, the cancer risk is considered low. In view of the limited studies from UAE in relation to the metal content of road-deposited dusts, the current study serves as novel knowledge, especially in the context of geographical areas with a higher occurrence of sandstorms and the presence of particulate matter. The study also adds to the global understanding of the contribution of street dust to environmental pollution and its implications for human health.

Boosting the pseudocapacitance of BiFeO3 by Zn doping for flexible battery-supercapacitor hybrid devices

Perovskite BiFeO3 (BFO) as a type of battery-type electrode materials, usually suffers from poor electrolyte ion transport in the BFO crystal. We propose a novel strategy of Zn doping to improve the ion transport and boost the faradaic pseudocapacitance of BFO for flexible battery-supercapacitor hybrid (BSH) devices. The Zn-doped BFO (Z-BFO-1) with the low Zn doping content, can maintain the crystal structure of BFO and the uniform distributions of elements. The oxygen vacancy content can be increased from BFO to Z-BFO-1, reflecting the influence of the Zn doping on the crystal structure of BFO. The Z-BFO-1 electrode with the stable crystal structure in the charge/discharge process, can provide the highest specific capacitance (223 F g−1 at 0.2 A/g) and the largest Li+ diffusion coefficient (2.386 × 10−11 cm2 s−1) among these BFO-based electrodes with different Zn doping contents. The first-principles calculations reveal that the Zn doping in BFO can significantly enhance the built-in electric fields and greatly lower the Li+ migration energy barriers (from 2.08 eV to 1.43 eV). This flexible MnO2//Z-BFO-1 BSH device with the high energy density (37.5 Wh kg−1 at 0.23 kW kg−1), opens up a new avenue for developing high-performance electrochemical energy storage devices.

Development and application of matte/speiss/metal thermodynamic database for optimization of processing of drosses, dusts and reverts from lead, zinc and copper production

Detrimental elements such as arsenic and antimony tend to accumulate in dusts and drosses of lead-zinc as well as copper smelters. These by-products are commonly treated in dedicated reductive smelting units producing Cu-rich matte, As-Sb-collecting speiss and Pb-rich metal, as well as liquid slag. Such process would have a complex distribution of elements (Cu, Fe, Pb, Zn, Ni, Sn, Sb, As, Ag, Au, S, etc.) among four liquid phases. Thermodynamic calculations can be used for predictions and optimization of such processes. They must rely on accurate models developed in integration with experimental program. Present study reports results of recent progress in experimental and modelling studies of As, Sb-containing speiss systems and demonstration of calculations relevant for industrial conditions. Experimental methodology consisted of equilibration, quenching and electron probe X-ray microanalysis. Calculations were performed using FactSage software and thermodynamic database developed based on the dedicated recent experiments. The main findings of the paper are: a set of binary and ternary diagrams relevant to matte and speiss formation conditions; distribution of Ag and Au among liquid Pb and speiss in key quaternary systems; and distributions of 10 main elements for industrially relevant matte/speiss/metal multicomponent equilibria.

Effects of h-BN content and heat treatment temperature on the tribological behavior and toughness of laser-clad Mo2FeB2/WC/h-BN coatings

In this study, h-BN-modified Mo2FeB2/WC composite coatings were fabricated via laser cladding. The Mo2FeB2/WC/10 wt.% h-BN composite coatings were heat-treated at 400, 600, and 800 °C. The microstructure, microhardness, tribological properties, residual stress, fracture toughness and fracture morphology of the coatings were investigated. The results showed that h-BN addition combined with heat treatment promoted the distribution of elements and finer microstructure. The Mo2FeB2/WC/10 wt.% h-BN coating heat-treated at 600 °C showed the highest microhardness (1416.8 HV0.5) among the prepared coatings. The pristine and 600 °C heat-treated Mo2FeB2/WC/10 wt.% h-BN coating showed excellent wear rates (1.97 and 1.84×10-5 mm3/Nm, respectively). The composite coatings modified with h-BN exhibited an abrasive wear mechanism after heat treatment. As the h-BN content and heat treatment temperature increased, there was a notable decrease in residual stress. Specifically, the coating subjected to heat treatment at 800°C demonstrated the lowest residual tensile stress recorded at 168 MPa. Conversely, when heat-treated at 600°C, the coating exhibited an optimal fracture toughness of 14.96 MPa·m1/2, with fracture behavior consistent with typical brittle fracture characteristics.

Visualization of oxygen vacancies at CeO x /Y-HZO interface by spectrum imaging method and multivariate analysis

Electron energy loss spectroscopy—spectrum imaging measurements using a scanning transmission electron microscope are carried out to clarify the details of microstructure at the interface of the CeO x -capped Y-HZO film prepared by the chemical solution deposition (CSD) method. We confirmed that by the present CSD the independent capped layer of CeOx successively deposited on Y-HZO. The crystal structure of CeO x film is mainly the cubic CeO2 structure with Ce4+. Chemical state maps are also successfully obtained by the multivariate analysis. We found that Ce3+ and Ce4+ coexist in the interface layer with cubic CeO2 crystal structure containing O vacancy. The results of the quantitative elemental distribution maps of energy dispersive X-ray spectroscopy also supported that O vacancies exist at the interface.

A comparative study on the electrocatalytic OER activity of mesoporous high-entropy oxide and medium-entropy oxide nanoparticles through SCS method

Developing readily available and cost-effective electrocatalysts as an alternative to the noble metals is a critical issue for renewable hydrogen energy generation. Mesoporous high-entropy oxides (HEOs) are among the most noteworthy candidates in the kinetically challenged process of oxygen evolution reaction (OER); The current study notifies the successful fabrication, and characterization of a series of meso-structured HEOs (5 elements) and MEOs (4 elements) nanopowders with remarkable electrocatalytic performance. Obtained results reveal that the synthesized HEOs and MEOs nanocompounds are meso-structured (with pore size of ⁓43–67 Å) with particle size of ⁓20–30 nm. Combusted HEOs and MEOs powders have high crystallinity degree (derived from XRD analysis) and homogenous elemental distributions. The electrocatalytic activity of the prepared HEOs and MEOs nanopowders were studied using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) analyses. It was specified that HEO nanoparticles (HEO 0.95 sample) exhibit superior electrocatalytic performance compared to MEOs particles with respect to their overpotential of 310 mV at 10 mA cm−2 and Tafel slope of 53 mV.dec−1. The drop of the charge transfer resistance (RCT) and increase of the conductivity in HEO 0.95 sample contributes to the improved electrocatalytic OER activity of the HEOs nanopowders. Taking ECSA into account, the improved electrocatalytic activity of meso-structured HEO 0.95 sample relates to the large number of active sites in this sample. The XRD, TEM, and FE-SEM results of HEO 0.95 sample after OER analysis indicated no alteration in phase composition and morphology revealing the reusability of the synthesized nanoparticles. This study also provides an insight into the behavior of Co, Ni, Cu elements as typical electrocatalysts as well as Zn and Mg elements as obscure electrocatalysts for efficient OER electrocatalysis. Furthermore, the impact of adiabatic temperature, crystallinity degree and physicochemical features of meso-structured particles on electrocatalytic performance are explored.

Effect of stapes demineralisation on the development of cochlear otosclerosis.

The involvement of the inner ear in otosclerosis may lead to the development of cochlear otosclerosis. The aim of this study was to analyse changes in the chemical composition and microstructure of the stapes in the course of otosclerosis compared to healthy stapes. This analysis included 31 patients with otosclerosis and 9 patients without otosclerosis. Microanalytical and diffraction techniques were used to assess the elemental distribution and orientation topography of the stapes. The concentration of Ca2+ in the study group was significantly lower in the area of the anterior crus of the stapes than in the posterior crus. A reduction in the Ca2+/P3+ ratio in the anterior crus was associated with deteriorated bone conduction and tinnitus. Degradation of the stapes microstructure in the area of otosclerotic lesions was observed with scanning electron microscopy. Bone remodelling is most significant at the closest location to typical otosclerotic lesions with hydroxyapatite porosity and scale-like bone formation according to scanning electron microscopy. There is a relationship between the disturbance of calcium metabolism and the development of clinical symptoms of cochlear otosclerosis.