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In this study, a facile thermal condensation method was employed to prepare graphitic carbon nitride (g-C3N4) nanoparticles, and characterised by different advanced techniques. The TEM results proved that g-C3N4 had an average size of 49.7–89.3 nm. The EDX analysis of g-C3N4 confirms the existence of only C and N elements. Polyethylene oxide/polyacrylamide (PEO/PAAm) hydrogel and PEO/PAAm/g-C3N4 nanocomposite of different ratios of g-C3N4 (5, 10, and 15%) were synthesised by gamma irradiation-induced crosslinking reaction. In addition, novel magnetic (PEO/PAAm/g-C3N4/Fe3O4) nanocomposite was successfully fabricated by alkaline co-precipitation of swollen PEO/PAAm/g-C3N4 in Fe3+/Fe2+ solutions for use in the removal of Sr2+, Zn2+, and Cd2+ ions from wastewater. The PEO/PAAm/g-C3N4/Fe3O4 nanocomposite was characterised by FTIR, XRD, SEM, EDX, and VSM techniques. The XRD of PEO/PAAm/g-C3N4/Fe3O4 nanocomposite showed the presence of the typical peaks of both g-C3N4 and Fe3O4 nanoparticles. The VSM analysis indicated that the saturation magnetisation value of the nanocomposite was 18.96 emu/g, which is suitable for magnetic separation and adsorption processing. The uptake ability of PEO/PAAm/g-C3N4/Fe3O4 nanocomposite towards the Sr2+, Zn2+, and Cd2+ was examined under the effect of pH, reaction time, pH, and adsorbent dosage as well as different adsorption kinetics and isotherms models were applied. The maximum removal percentage of Cd2+, Zn2+, and Sr2+ ions was 89.8%, 97.3%, and 91.5% and achieved after 25 min at the optimum pH of 6 for Cd2+ and Zn2+, and pH 4.0 for Sr2+ ions. The fast and easy uptake of PEO/PAAm/g-C3N4/Fe3O4 nanocomposite adsorbent for the pollutants owing to the synergistic effect of existing functional groups of PEO/PAAm as well as g-C3N4 and Fe3O4 improved the removal performance of metal ions for great application in environmental remediation of wastewater treatments. [ABSTRACT FROM AUTHOR]

AbstractIn this study the cryptands [2=N.2=N.2=N] and [2N=.2N=.2N=] were investigated using quantum chemistry methods (B3LYP/LANL2DZp). The evaluation of model reaction energy values clearly showed that in the [2=N.2=N.2=N] system, Na+ and K+ ions are best suitable for the cryptand, with a slight preference for K+. The Sr2+ is the best fitting alkaline earth ion, followed by the Ca2+ ion. [2N=.2N=.2N=] clearly prefers the smaller ions. The sodium cation is undoubtedly the favorite, with the potassium ion coming in second. The magnesium ion is the most stable, with the calcium and strontium ions having the next most stable energetic values. The investigation of the M-N bond lengths corroborates the findings of the energetic criteria, confirming the same picture and ion selectivity. These differences in ion selectivity are a result of the differing flexibility of the two cryptands under investigation [2=N.2=N.2=N] and [2N=.2N=.2N=]. The cryptand [2=N.2=N.2=N] optimizes its dihedral angle to host guest cations effectively, while [2N=.2N=.2N=] gains greater flexibility from its C-N … N-C dihedral angle. The greater flexibility of [2N=.2N=.2N=] allows it to form a more suitable cavity to nest the guests due to the different location of the imine double bond in the bridges of the cryptates. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament (ACL) injuries in sports have become increasingly prevalent, leading to the widespread adoption of polyethylene terephthalate (PET) artificial ligaments for ACL reconstruction due to their superior mechanical properties. However, the bio‐inertness of PET presents a significant challenge to graft‐bone integration, necessitating the enhancement of PET surface bioactivity. This study employed magnetron sputtering and hydrogel coating techniques to introduce strontium calcium‐phosphorus, and magnesium ions onto the surface of PET ligaments, achieving the sequential release of Mg, and Sr ions. The scanning electron microscopy analysis confirmed the uniformity and stability of the modified PET ligament surface material. The synergistic effect of sequential release from Mg/Sr‐PET has effectively promoted osteogenesis, angiogenesis, and neuronal differentiation in vitro. Moreover, in the reconstructed ACL model using Sprague‐Dawley rats, the histological staining, micro‐computed tomography, and biomechanical test results indicated that the Mg/Sr‐PET group notably stimulated blood vessel and nerve formation, demonstrating remarkable bone regrowth promotion. In conclusion, the sequential release and synergistic effect of magnesium and strontium ions significantly enhanced graft‐bone integration and accelerated rapid healing, offering valuable insights for improving clinical ACL reconstruction outcomes. [ABSTRACT FROM AUTHOR]

Bioactive glasses (BGs) have emerged as invaluable resources for bone tissue engineering due to their remarkable properties such as bioactivity, resorbability, cell compatibility, and osteoconductivity. However, these materials exhibit certain limitations when subjected to high temperatures, for their tendency to crystallize, thus leading to diminished bioactivity, reduced mechanical strength, and altered dissolution kinetics. One promising approach to counteract this problem is to reduce the alkaline element content in BGs while simultaneously adding strontium and magnesium. Building on previous studies of Bio_MS, a recently developed experimental formulation, we investigated the contributions of strontium and magnesium to the thermal, mechanical, and biological properties of various bioactive glasses, including commercially available options. Differential thermal analysis, heating microscopy, X-ray diffractometry, environmental scanning electron microscopy, measurement of the Young's modulus, simulated body fluid testing, cytotoxicity tests, cell viability, growth, adhesion and morphology were assessed through an integrated approach and compared for a complete evaluation of BGs, and of doped BGs, also undergoing thermal treatments. The results demonstrated improved thermal, mechanical and biological behaviors of the magnesium-strontium-doped BGs, thus paving the way for the development of BGs with enhanced biomedical perspectives. [ABSTRACT FROM AUTHOR]

This study investigated the influence of specific dopant ions strontium (Sr2+), zinc (Zn2+), silver (Ag+), and fluoride (F−) on the functionality of composite doped hydroxyapatite (CD-HA) materials. A well-known optimization technique i.e., Taguchi's design of experiments was employed to identify the ideal dopant concentrations in HA. This approach aimed to achieve a desired dielectric constant (DC), a key electrical property, while simultaneously promoting favourable biological properties for potential tissue engineering applications. Compared to undoped HA, specific CD-HA L6 (2.5Sr-5.0Zn-2.5 F) and L9 (5.0Sr-5.0Zn-2.5Ag) compositions exhibited significantly increased dielectric constants, reaching up to 145% higher values. The finding suggest that these nutrient doped HA could be beneficial in applications where electrical stimulation play a crucial role for bone growth. Further, L6 and L9 samples demonstrated nearly double the cell proliferation rate compared to undoped HA. In addition to cell material interaction, the antibacterial activity of both undoped HA and CD-HA samples against Escherichia coli and Staphylococcus aureus bacteria was conducted successfully. Notably, the L9 (5.0Sr-5.0Zn-2.5Ag) composition displayed the strongest antibacterial effect, with the largest inhibition zone against E. coli. These aforementioned findings suggested that these bio-ceramic CD-HA compositions containing 5% Sr and Zn, along with 2.5% Ag and F can be used as the potential candidates for various biomedical applications. [ABSTRACT FROM AUTHOR]

The aim of the present study is to synthesize Cu1−xSrxS (x = 0.00, 0.025, 0.05, 0.075, and 0.1) nanoparticles (NPs) using an easy chemical co-precipitation method in an efficient, inexpensive, and simple technique. The structural, morphological, and optical properties of the prepared samples were investigated using XRD, TEM, XRF, UV–Vis DRS, and PL characterization techniques. XRD spectra confirmed the Sr-doped copper sulfide nanoparticles have a hexagonal structure with crystallite sizes ranging from 15.15 to 16.04 nm, and, by XRF, the presence of the dopant was detected. TEM analysis confirmed that strontium ions had an effect on the shape of the CuS nanostructure, and the particle size increased from 16.27 to 17.32 nm after doping. A study using UV-Vis showed the presence of Sr doping increased the optical energy band gap (1.38 eV to 1.59 eV). At room temperature, one photoluminescence (PL) band was found at 826 nm. The antibacterial activity of CuS nanostructures against E. coli, P. aeruginosa, Klebsiella pneumonia, and S. aureus was evaluated by zone of inhibition. Sr doped CuS NPs exhibited the highest antibacterial activity against S. aureus (17 to 29 mm). Also, the results demonstrated that samples doped with 5, 7.5, and 10% Sr exhibited inhibitory effects against all the tested microbial strains higher than the antibiotic. [ABSTRACT FROM AUTHOR]

Heavy metal contamination especially in aqueous media has become an important risk to human health and environment. Therefore, due to the broad distribution of barium (Ba2+) and strontium (Sr2+) ions in the environment and wide variety of their harmful health effects for human, development of efficacious systems for their accurate and selective determination is of great importance. Aiming to develop a point-of-care and easy-to-use sensing device, a paper-based colorimetric sensing device was designed for simultaneous measurement of Ba2+ and Sr2+ ions standing on the basis of the color change of sodium rhodizonate (SR) in the presence of various concentrations of the target analytes. These color changes were photographed using a smartphone, and after analyzing with Photoshop 2022 software, the average variations in the intensities of colors (RGB (red, green, blue) model) were used to draw the calibration curves. The quantitative identification of Ba2+ and Sr2+ ions in a single solution was carried out by masking one of them at a moment. The average color intensities (G) displayed a linear relationship with the concentration of the analytes in the ranges of 5––300 ppm and 5–350 ppm with the limit of detection (LOD) values of 3.64 and 4.75 ppm for Ba2+ and Sr2+ ions, respectively. Moreover, the selectivity of the proposed analytical device was assessed; SR was selective for the target analytes versus the other ions causing a considerable color change. Furthermore, the practical application of this colorimetric device was investigated by the excellent performance in real samples indicating its potential for field applications. [ABSTRACT FROM AUTHOR]

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The objective behind developing the nanoporous alumino-borosilicate (AlBS) was to remove strontium ion (Sr2+) from liquid waste and subsequently stabilize it. The sorption capacity of the nanoporous AlBS was assessed in relation to various experimental factors, including contact time, temperature, initial pH solution, and initial concentration of Sr ions. According to the obtained results, nanoporous AlBS shows a maximum Sr2+ sorption capacity of 163.08 mg/g. In order to achieve stable immobilization of the sorbed Sr ions, heat treatments at different temperatures were applied to the Sr-containing nanoporous AlBS. Various eluents were used in the leach tests to examine the Sr ions leaching from heat-treated materials. Only 3.43% of the Sr ions initially adsorbed in the nanoporous AlBS matrix was washed out with 1 M sodium chloride eluent, showing that heating the sample to around 1100 °C successfully trapped Sr ions in the nanoporous AlBS matrix. [ABSTRACT FROM AUTHOR]

Inflammatory responses play a central role in coordinating biomaterial‐mediated tissue regeneration. However, precise modulation of dynamic variations in microenvironmental inflammation post‐implantation remains challenging. In this study, the traditional β‐tricalcium phosphate‐based scaffold is remodeled via ultrathin MXene‐Ti3C2 decoration and Zn2+/Sr2+ ion‐substitution, endowing the scaffold with excellent reactive oxygen species‐scavenging ability, near‐infrared responsivity, and enhanced mechanical properties. The induction of mild hyperthermia around the implant via periodic near‐infrared irradiation facilitates spatiotemporal regulation of inflammatory cytokines secreted by a spectrum of macrophage phenotypes. The process initially amplifies the pro‐inflammatory response, then accelerates M1‐to‐M2 macrophage polarization transition, yielding a satisfactory pattern of osteo‐immunomodulation during the natural bone healing process. Later, sustained release of Zn2+/Sr2+ ions with gradual degradation of the 3D scaffold maintains the favorable reparative M2‐dominated immunological microenvironment that supports new bone mineralization. Precise temporal immunoregulation of the bone healing process by the intelligent 3D scaffold enhances bone regeneration in a rat cranial defect model. This strategy paves the way for the application of β‐tricalcium phosphate‐based materials to guide the dynamic inflammatory and bone tissue responses toward a favorable outcome, making clinical treatment more predictable and durable. The findings also demonstrate that near‐infrared irradiation‐derived mild hyperthermia is a promising method of immunomodulation. [ABSTRACT FROM AUTHOR]

Developing suitable cathodes with high capacity and high power is challenging for K‐ion batteries. Herein, electrochemical K‐ion storage properties of the layered‐type K0.4V2O5 (KVO) cathode by incorporating divalent strontium ions (Sr2+) into its crystal structure are enhanced. Divalent strontium ions (1.18 Å) are preferentially incorporated into the octahedrally coordinated K (1.38 Å) layers due to the similar ionic size compared to V4+ (0.58 Å). The introduction of 3 mmol of Sr ions in the KVO crystal improves electrical conductivity and reduces K‐ion diffusion energy barriers. In addition, the strong Sr2+ and O2− interaction acts as a structural pillar, suppressing irreversible phase transition during charge–discharge process. Multi‐physics simulations clearly confirm that the K0.34Sr0.03V2O5 (KS3VO) cathode exhibits a more uniform K‐ion distribution and enhanced reactions of K‐ions compared to the KVO cathode at various depths of discharge. As a result, the KS3VO cathode demonstrates improved reversible capacity, cycling stability, and power capability over the KVO cathode in a K‐ion cell. Synchrotron X‐ray analysis reveals how Sr substitution enhances the electrochemical K‐ion storage properties of the KS3VO cathode. In addition, the KS3VO cathode exhibits superior thermal stability and cycling stability in a full cell coupled with a hard carbon anode compared to the KVO cathode. [ABSTRACT FROM AUTHOR]

Cartilage tissue engineering holds great promise for efficient cartilage regeneration. However, early inflammatory reactions to seed cells and/or scaffolds impede this process. Consequently, managing inflammation is of paramount importance. Moreover, due to the body's restricted chondrogenic capacity, inducing cartilage regeneration becomes imperative. Thus, a controlled platform is essential to establish an anti-inflammatory microenvironment before initiating the cartilage regeneration process. In this study, we utilized fifth-generation polyamidoamine dendrimers (G5) as a vehicle for drugs to create composite nanoparticles known as G5-Dic/Sr. These nanoparticles were generated by surface modification with diclofenac (Dic), known for its potent anti-inflammatory effects, and encapsulating strontium (Sr), which effectively induces chondrogenesis, within the core. Our findings indicated that the G5-Dic/Sr nanoparticle exhibited selective Dic release during the initial 9 days and gradual Sr release from days 3 to 15. Subsequently, these nanoparticles were incorporated into a gelatin methacryloyl (GelMA) hydrogel, resulting in GelMA@G5-Dic/Sr. In vitro assessments demonstrated GelMA@G5-Dic/Sr's biocompatibility with bone marrow stem cells (BMSCs). The enclosed nanoparticles effectively mitigated inflammation in lipopolysaccharide-induced RAW264.7 macrophages and significantly augmented chondrogenesis in BMSCs cocultures. Implanting BMSCs-loaded GelMA@G5-Dic/Sr hydrogels in immunocompetent rabbits for 2 and 6 weeks revealed diminished inflammation and enhanced cartilage formation compared to GelMA, GelMA@G5, GelMA@G5-Dic, and GelMA@G5/Sr hydrogels. Collectively, this study introduces an innovative strategy to advance cartilage regeneration by temporally modulating inflammation and chondrogenesis in immunocompetent animals. Through the development of a platform addressing the temporal modulation of inflammation and the limited chondrogenic capacity, we offer valuable insights to the field of cartilage tissue engineering. [ABSTRACT FROM AUTHOR]

This study provides and investigates the fabrication of graphene oxide (GO) sheets decorated with chitosan nanoparticles (CSNP) through the hybridizing of GO and CS, by the addition of tetraethyl orthosilicate (TEOS) as a cross-linker agent. The fabricated GO-CSNP composite was characterized using several advanced techniques. Furthermore, various parameters affect the sorption of Sr(II), such as contact time, pH, initial concentration, dosage, temperature, and coexisting ions. The experimental results were in accordance with the pseudo-second-order reaction. The interaction mechanism between Sr(II) and GO-CSNP composite was accurately described by the Langmuir isotherm model with a maximum adsorption capacity of 473.93 mg/g. The GO-CSNP composite demonstrated exceptional selectivity for the sorption of Sr(II) over Y(III) at a high concentration ratio of 10:1 for Sr2+ to Y3+, respectively. Furthermore, the GO-CSNP adsorbent demonstrated considerable potential as a highly effective sorbent for the adsorption of Sr(II), Mo(VI), Cd(II), and Cs(I) ions. The results revealed that the prepared composite was effectively capable of removing various fission products. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the biocompatibility of a novel bioceramic endodontic sealer formulation, combining tricalcium silicate/dicalcium silicate, silicon hydroxyapatite, and strontium hydroxyapatite. Methods: Sixty polyethylene tubes were filled with the following four materials (n = 15): AH Plus sealer, Sure-Seal Root bioceramic sealer, an experimental bioceramic sealer, and empty control tubes. Fifteen adult Wistar rats were used, each receiving all four tube types implanted subcutaneously on the dorsal skin. The rats were divided into three groups, evaluated at 15, 30, and 60 days postoperation. Histological analysis assessed inflammation, fibrous capsule thickness, giant cell infiltration, and biomineralization. The Kruskal-Wallis test was used for statistical analysis, with the significance level set at P < 0.05. Results: There were no statistically significant differences in tissue reaction measures among the groups (P > 0.05). Intragroup comparisons revealed a significant reduction in inflammation in the AH Plus group (P = 0.04). Fibrous capsule thickness and giant cell infiltration decreased significantly in the Sure-Seal Root and AH Plus groups over the experiment (P< 0.05). Biomineralization increased in the experimental sealer group but without statistical significance (P > 0.05). Conclusions: Sure-Seal Root and AH Plus sealers exhibited significant decreases in some tissue reactions over time, but the experimental sealer did not. Despite the lack of statistical significance in between-group comparisons, the biocompatibility of commercially available sealers appears to be better than the experimental sealer, based on the results of this study. [ABSTRACT FROM AUTHOR]

The use of biogenic calcium ions for the source of hydroxyapatite (HAp or HA) are very common and have been being explored extensively. However, it usually results high crystalline HA, due to high reaction and decomposition temperatures. In this study, strontium (Sr2+) doped HA from the golden apple snail shells (Pomacea canaliculate L) was successfully synthesized. It was indicated that Sr ions completely replaced calcium (Ca) ions, increased the lattice constant, and consecutively reduced HA crystallinity. Smaller crystal size and ß-type carbonate (CO3 2-) ions substitution with Ca/P close to 1.67 molar ratio that mimic bone crystals were observed in Sr-doped HA, with significant increased rate of MC3T3-E1 cells viability and higher IC50 values. It was proven that Sr ions substitution resolved challenges on the use of biogenic sources for HA fabrication. Further in vivo study is needed to continue to valorise the results into real biomedical and clinical applications. [ABSTRACT FROM AUTHOR]

Understanding the hydrochemical characteristics and genesis mechanisms of strontium-rich groundwater is pivotal for supporting the exploitation and utilization of natural strontium-rich groundwater. In this research, 27 groundwater samples were collected. By analyzing major ion chemistry and strontium isotope data, and considering the hydrogeological context, various analytical approaches, including multivariate statistics, ion ratios, and isotopes, were used to reveal the characteristics and genesis mechanisms of strontium-rich groundwater in the study area. The findings indicate that the predominant hydrochemical type of groundwater is HCO3-Ca, with Ca2+ and HCO3- as the primary cations and anions. The hydrochemistry of the strontium-rich groundwater is predominantly influenced by rock weathering processes. A combination of factors, including ion exchange, and anthropogenic activities, shapes the compositional characteristics of the groundwater in the region. The dissolution of calcite due to weathering emerges as the principal source of strontium in the groundwater. While ion exchange processes are not conducive to strontium enrichment in groundwater, their effect is relatively limited. The impact of human activities on the groundwater is minor. [ABSTRACT FROM AUTHOR]

This document discusses the development and application of advanced sorbents for the separation of metal ions. Traditional sorbents face limitations in terms of selectivity, efficiency, and cost-effectiveness, but advanced sorbents made from new and modified materials show promise in overcoming these challenges. These sorbents have high surface areas, tunable pore structures, and functionalized surfaces, which improve their metal-ion adsorption capacity, selectivity, and kinetics. The document highlights various applications for these sorbents, including water treatment, hydrometallurgy, environmental remediation, and analytical chemistry. The articles in this special issue explore different types of sorbents and their effectiveness in metal-ion separation, providing insights into their synthesis, adsorption mechanisms, and process optimization. Future studies should focus on scaling up these sorbent applications, improving their selectivity and efficiency, and incorporating them into comprehensive process systems to meet the increasing demands for metals and environmentally friendly waste management solutions. [Extracted from the article]

Sorption of Sr(II) and Eu(III) from aqueous solutions was studied using tin molybdate talc sorbent synthesized by the precipitation technique. The synthesized sorbent was characterized using different analytical tools, such as; FT-IR, SEM, XRD, XRF, TGA, and DTA. The sorption studies applied to Sr(II) and Eu(III) include the effects of shaking time, pH, concentrations, and saturation capacity. The sorption of Sr(II) and Eu(III) depends on pH, reaction kinetics obey the pseudo-2nd-order model, and the Langmuir model is better suited for the sorption isotherm. The thermodynamic parameters reflect an endothermic and spontaneous sorption process. Desorption studies showed that 0.1 M HCl was the best desorbing agent for the complete recovery of Sr(II) (96.8%) and Eu(III) (92.9%). Finally, the obtained data illustrates that the synthesized sorbent can be applied and used as an efficient sorbent for the sorption of Sr(II) and Eu(III) from aqueous solutions and can be used as a promising sorbent to remove Sr(II) and Eu(III). [ABSTRACT FROM AUTHOR]

The cost‐effectiveness and environmentally friendly nature of aqueous zinc‐ion batteries (ZIBs) have garnered significant attention. Nevertheless, obstacles such as dendrite growth and side reactions have hindered their practical application. Here, an alkaline earth metal ion, strontium ions (Sr2+), is chosen as a dual‐functional electrolyte additive to improve the reversibility of ZIBs. Importantly, Sr2+ ions adsorb on the anode surface, creating a dynamic electrostatic shield layer, thus regulating the Zn2+ deposition behavior and suppressing side reactions. Meanwhile, Sr2+ ions prefer to adsorb on (002) and (110) planes of Zn, thus inducing the preferential deposition of (100) crystal plane and achieving dendrite‐free zinc anode. Consequently, the assembled Zn||Zn symmetric battery delivers an ultralong lifespan of 3500 h, and the Zn||Ti asymmetric battery shows a superior Coulombic efficiency of 99.8% for Zn stripping/plating at 2 mA cm−2. Further, the Zn||NH4V4O10 battery presents an excellent retention of 97.7% over 800 cycles under 2 A g−1. This research introduces a novel alkaline earth metal ion electrolyte additive and establishes its persistent dynamic electrostatic shielding effect and preferentially oriented (100) plane plating, ensuring dendrite‐free zinc deposition. These findings chart a course for further exploration of unexplored alkaline earth elements in enhancing metal battery technologies. [ABSTRACT FROM AUTHOR]

The geochemical cycle of strontium is intimately linked to the long-term cycle of carbon, for instance, through their mutual involvement in continental weathering and marine carbonate sedimentation. Stable strontium isotopes (δ 88/86Sr) have recently emerged as a valuable tool, complementing radiogenic Sr isotope ratios (87Sr/86Sr), to further our understanding of the Sr cycle. Stable strontium isotopes are sensitive to both the sources of strontium (e.g., silicate versus carbonate weathering) and to earth surface processes (e.g., mineral precipitation from solution). Gypsum, a common evaporitic mineral, precipitates directly from seawater and holds the potential to serve as a marine archive for studying the elemental cycle of Sr. In addition, the impact of gypsum formation on the marine strontium isotope budget has been a matter of speculation due to the limited information on the isotope fractionation of Sr in gypsum. Here, we explore the behavior of strontium isotopes during gypsum precipitation and provide the first-order estimates of the associated isotope fractionation. Gypsum was produced through the evaporation of natural seawater in a series of experiments. Strikingly, in contrast to the fractionation of Ca isotopes into gypsum, as well as Sr isotopes into carbonate minerals, heavier isotopes of Sr are preferentially incorporated into gypsum with an estimated average isotope fractionation of ∼0.20‰ (range between 0.14–0.27‰). The variability in the observed experimental isotope fractionation is suggested to be the result of admixture of aragonite in the precipitate, surface-specific rate-controlled effects, and/or mineral occlusion (i.e., capturing of unfractionated Sr). Despite these complications, gypsum has the potential to effectively resolve significant variations in past seawater δ 88/86Sr following the suggested approach, which involves careful sample selection based on radiogenic Sr data, avoidance of aragonite admixtures, and ensuring a large dataset of coeval samples. Mass balance considerations indicate that the formation of giant evaporite deposits has the potential to induce only minimal, short-term, alterations in seawater δ 88/86Sr, largely not discernible due to the uncertainties in the existing Sr isotope records. Finally, we find that weathering of 88Sr-enriched marine gypsum exposed on the continents is likely a significant source of Sr to the ocean. This Sr source can explain at least 25% of the apparent mismatch between the observed global riverine δ 88/86Sr and that estimated from the weathering of carbonate and silicate lithologies only. [ABSTRACT FROM AUTHOR]

Mesoporous bioactive glass nanoparticles (MBGNs) doped with therapeutical ions present multifunctional systems that enable a synergistic outcome through the dual delivery of drugs and ions. The aim of this study was to evaluate influence of co-doping with strontium and magnesium ions (SrMg-MBGNs) on the properties of MBGNs. A modified microemulsion-assisted sol–gel synthesis was used to obtain particles, and their physicochemical properties, bioactivity, and drug-loading/release ability were evaluated. Indirect biological assays using 2D and 3D cell culture models on human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and endothelial EA.hy926 cells, respectively, were used to determine biocompatibility of MBGNs, their influence on alkaline phosphatase (ALP) production, calcium deposition, and cytoskeletal organization. Results showed that Sr,Mg-doping increased pore volume and solubility, and changed the mesoporous structure from worm-like to radial–dendritic, which led to a slightly accelerated drug release compared to pristine MBGNs. Biological assays confirmed that particles are biocompatible, and have ability to slightly induce ALP production and calcium deposition of hBM-MSCs, as well as to significantly improve the proliferation of EA.hy926 compared to biochemical stimulation via vascular endothelial growth factor (VEGF) administration or regular media. Fluorescence staining revealed that SrMg-MBGNs had a similar effect on EA.hy926 cytoskeletal organization to the VEGF group. In conclusion, Sr,Mg-MBGNs might be considered promising biomaterial for biomedical applications. [ABSTRACT FROM AUTHOR]

This article examined reducing the hazardous effects of Sr(II) and Co(II) using a sodium-based purolite C100 cation exchange adsorbent. The sorption behaviour of Sr(II) and Co(II), including the impact of time, pH, initial concentrations, and temperature. The results reveal that purolite C100 has a fast equilibrium time and follows pseudo-2nd-order kinetics. The saturation capacity has high values of 190.5 and 182.1 mg g−1 for Sr(II) and Co(II), respectively. The Langmuir isotherm model is more applicable than other isotherm models. Negative Gibbs energy values demonstrated the excellent feasibility and spontaneity of the sorption process. Positive enthalpy readings indicate that this process was endothermic. Positive entropy values demonstrated that the disorder between the solid and liquid phases was enhanced during adsorption. Desorption of Sr(II) and Co(II) from the loaded purolite C100 was done by KCl (99.2%) and CaCl2 (99.3%), respectively. The recycling results indicated that the purolite C100 should be reused for repeated sorption-desorption regeneration cycles up to 14 cycles, with a low reduction in the uptake percentage. The excellent recycling results reveal the applicability of the purolite C100 to be used as an effective cation exchange adsorbent for the sorption of Sr(II) and Co(II) from aqueous media. [ABSTRACT FROM AUTHOR]

The release and escape of radioactive materials has posed tremendous threats to the global environment. Among various radioactive elements, 90Sr has attracted growing attention due to its long half-life and its tendency to accumulate in bone tissue. Nonetheless, the concentration of 90Sr in radioactive waste is exceedingly low, far below the detection limits of currently available strontium-targeting chemical sensors. Herein, we propose an optical nanosensor (Sr2+-nanosensor) that exhibits an ultra-low detection limit of 0.5 nM, surpassing the 90Sr in the treated radioactive water from the Fukushima. The sensor offers wide sensing range of eight orders of magnitude, rapid response of less than 10 s, and high selectivity against 31 common ions. These excellent performances are attributed to a specific ligand (Sr2+-ligand) for Sr2+ recognition. The Sr2+ is found to be bound by six oxygen atoms from the Sr2+-ligand with a stability constant at least two orders higher than that of other traditional ligands. This study offers invaluable insights for the design of Sr2+-sensing methodologies as well as a technique for detecting trace amounts of environmental radioactive pollution. The release and escape of radioactive 90Sr has attracted growing attention due to its long half-life and its tendency to accumulate in bone tissue. Herein, the authors report an optical nanosensor (Sr2+-nanosensor) that exhibits an ultra-low detection limit of 0.5 nM, a rapid response of less than 10 s, and high selectivity against 31 common ions. [ABSTRACT FROM AUTHOR]

This study aimed to compare the biological properties of newly synthesized cements based on calcium phosphate with a commercially used cement, mineral trioxide aggregate (MTA). Strontium (Sr)-, Copper (Cu)-, and Zinc (Zn)-doped hydroxyapatite (miHAp) powder was obtained through hydrothermal synthesis and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray spectrometry (EDX). Calcium phosphate cement (CPC) was produced by mixing miHAp powder with a 20 wt.% citric acid solution, followed by the assessment of its compressive strength, setting time, and in vitro bioactivity. Acetylsalicylic acid (ASA) was added to the CPC, resulting in CPCA. Biological tests were conducted on CPC, CPCA, and MTA. The biocompatibility of the cement extracts was evaluated in vitro using human dental pulp stem cells (hDPSCs) and in vivo using a zebrafish model. Antibiofilm and antimicrobial effect (quantified by CFUs/mL) were assessed against Streptococcus mutans and Lactobacillus rhamnosus. None of the tested materials showed toxicity, while CPCA even increased hDPSCs proliferation. CPCA showed a better safety profile than MTA and CPC, and no toxic or immunomodulatory effects on the zebrafish model. CPCA exhibited similar antibiofilm effects against S. mutans and L. rhamnosus to MTA. [ABSTRACT FROM AUTHOR]

Nickel substituted Sr–Co nano spinel ferrites with composition Sr 0.5-x Ni x Co 0.5 Fe 2 O 4 (0.0, 0.1, 0.2, and 0.3) were prepared with the help of a sol-gel auto combustion route. The prepared materials were sintered at 800 for four and a half hours. Analysis of XRD confirmed that the material is composed of a cubic spinel structure with a single phase, and its space group is Fd-3m. Rietveld refinement of X-ray diffraction data was done for all prepared compositions using FULLPROF software. As the composition under study contains more nickel than lattice constant, crystalline size, X-ray density, and bulk density decrease. The dielectric properties were observed about frequency. The dielectric properties revealed that dielectric loss, dielectric constant, and ac conductivity decrease with increasing the Ni2+ content. The activation energy (ΔE) was calculated from the slope of Arrhenius plots. The ΔE found in the range of 0.580–0.096 eV. The analysis of XPS was carried out to examine the elemental state of annealed samples. The prepared material is suitable for employment in applications involving high frequencies because the Ni-doped Sr–Co ferrites with the greatest Ni2+ concentration have the lowest dielectric loss, dielectric constant, and tangent loss value. [ABSTRACT FROM AUTHOR]

New gelatin methacryloyl (GelMA)—strontium-doped nanosize hydroxyapatite (SrHA) composite hydrogel scaffolds were developed using UV photo-crosslinking and 3D printing for bone tissue regeneration, with the controlled delivery capacity of strontium (Sr). While Sr is an effective anti-osteoporotic agent with both anti-resorptive and anabolic properties, it has several important side effects when systemic administration is applied. Multi-layer composite scaffolds for bone tissue regeneration were developed based on the digital light processing (DLP) 3D printing technique through the photopolymerization of GelMA. The chemical, morphological, and biocompatibility properties of these scaffolds were investigated. The composite gels were shown to be suitable for 3D printing. In vitro cell culture showed that osteoblasts can adhere and proliferate on the surface of the hydrogel, indicating that the GelMA-SrHA hydrogel has good cell viability and biocompatibility. The GelMA-SrHA composites are promising 3D-printed scaffolds for bone repair. [ABSTRACT FROM AUTHOR]

In the present work, La3+ ion substituted strontium Z-type hexaferrites (Sr3-xLaxCo2Fe24O41 (x = 0, 0.05, 0.10, 0.15, 0.20, and 0.25)) have been synthesized using solid-state reaction method. The effect of substitution on its structural and magnetic properties was investigated. X-ray diffraction (XRD) pattern confirms the formation of single-phase Z-type hexaferrite. The XPS spectra provide the evidence for formation of Fe2+ in La-substituted SrZ hexaferrites. FESEM micrographs of as prepared samples showed a reduction in grain size with the increasing La substitution. The behavior of substitution at various crystallographic sites was analyzed by Raman spectroscopy. The increase in saturation magnetization (Ms) and coercivity (Hc) was observed with increasing La content from x = 0 to x = 0.25. [ABSTRACT FROM AUTHOR]

Spodoptera frugiperda, an invasive pest insect that targets maize and other crops, first arrived in Japan in the summer of 2019. This species occurs year‐round in East Asian subtropical regions such as southern mainland China and the island of Taiwan, where the mean air temperature in the coldest month is above 10°C. Adults are similarly found throughout the year on the southwestern islands of Japan. Trap monitoring there showed continuous or intermittent S. frugiperda catches in the three winter seasons since 2019. However, it was difficult to distinguish between immigrants arriving from these neighbouring areas and local individuals occurring on each Japanese island. In this study, the possible natal origin of captured insects on five small islands (Yonagunijima, Taramajima, Okinawajima, Amamioshima and Tanegashima) was determined by investigating the strontium radiogenic isotope ratios (87Sr/86Sr) and comparing them with those of reference hosts and insects. Since trapping data and the 87Sr/86Sr values of trapped insects didn't support S. frugiperda's winter breeding on the northernmost island, Tanegashima, further analysis was limited to the four southern islands. The 87Sr/86Sr values of reference host plants and reared insects on the four islands ranged from 0.70929 to 0.71009, while those of catch insects ranged from 0.70885 to 0.71090. The 87Sr/86Sr values of the catch insects and the reference on the four islands did not differ significantly. In addition, the monthly averages of daily mean air temperature in January and February 2020–2022 were above 10°C, and the wind direction at the surface was mostly from the northeast or northwest. These pieces of evidence, together with winter host availability, suggested that S. frugiperda occurs year‐round on the islands. In other words, the year‐round occurrence area of S. frugiperda in East Asia extends to the Japanese southwestern islands below Amamioshima Island. [ABSTRACT FROM AUTHOR]

In bone regeneration, combining natural polymer-based scaffolds with Bioactive Glasses (BGs) is an attractive strategy to improve the mechanical properties of the structure, as well as its bioactivity and regenerative potential. Methods: For this purpose, a well-studied alginate/hydroxyapatite (Alg/HAp) porous scaffold was enhanced with an experimental bioglass (BGMS10), characterized by a high crystallization temperature and containing therapeutic ions such as strontium and magnesium. This resulted in an improved biological response compared to 45S5 Bioglass®, the "gold" standard among BGs. Porous composite scaffolds were fabricated by freeze-drying technique and characterized by scanning electron microscopy and microanalysis, infrared spectroscopy, and microcomputed tomography. The mechanical properties and cytocompatibility of the new scaffold composition were also evaluated. The addition of bioglass to the Alg/HAp network resulted in a slightly lower porosity. However, despite the change in pore size, the MG-63 cells were able to better adhere and proliferate when cultured for one week on a BG scaffold compared to the control Alg/HAp scaffolds. Thus, our findings indicate that the combination of bioactive glass BGMS10 does not affect the structural and physicochemical properties of the Alg/HAp scaffold and confers bioactive properties to the structures, making the Alg/HAp-BGMS10 scaffold a promising candidate for future application in bone tissue regeneration. [ABSTRACT FROM AUTHOR]

This research article explores the effect of chromium doping on the non-linear optical properties of strontium tungstate nanostructures. The study analyzes the samples using various techniques such as X-ray diffraction, FTIR, Raman spectroscopy, and photoluminescence studies. The results show that chromium-doped samples exhibit high non-linear absorption coefficient values, and the concentration of chromium affects the absorption behavior. The article also discusses the crystal structure, morphology, and optical properties of the doped nanostructures. The findings suggest that chromium-doped strontium tungstate nanostructures have potential applications in optical limiting and optical switching. [Extracted from the article]

The efficient segregation of radioactive nuclides from low-level radioactive liquid waste (LLRW) is paramount for nuclear emergency protocols and waste minimization. Here, we synthesized Na3FePO4CO3 (NFPC) via a one-pot hydrothermal method and applied it for the first time to the selective separation of Sr2+ from simulated LLRW. Static adsorption experimental results indicated that the distribution coefficient Kd remained above 5000 mL·g−1, even when the concentration of interfering ions was more than 40 times that of Sr2+. Furthermore, the removal efficiency of Sr2+ showed no significant change within the pH range of 4 to 9. The adsorption of Sr2+ fitted the pseudo-second-order kinetic model and the Langmuir isotherm model, with an equilibrium time of 36 min and a maximum adsorption capacity of 99.6 mg·g−1. Notably, the adsorption capacity was observed to increment marginally with an elevation in temperature. Characterization analyses and density functional theory (DFT) calculations elucidated the adsorption mechanism, demonstrating that Sr2+ initially engaged in an ion exchange reaction with Na+. Subsequently, Sr2+ coordinated with four oxygen atoms on the NFPC (100) facet, establishing a robust Sr-O bond via orbital hybridization. [ABSTRACT FROM AUTHOR]

The structure, oxygen non-stoichiometry, thermomechanical and electrical properties of perovskite-type BaFe1−xCexO3−δ (x = 0.05, 0.10, 0.15) were studied in the light of the potential use of these oxides as electrode materials of solid oxide fuel cells. Partial substitution of iron by cerium in barium ferrite was shown to stimulate water incorporation into oxygen vacancies. This phenomenon is manifested by dehydration during heating, which is clearly registered by thermogravimetric and dilatometric measurements. Different behavior of cerium ions residing in the A- and B-sublattices of perovskite-type ferrites was revealed. In contrast to Sr1−xCexFeO3−δ oxide series, in which the concentration of Ce3+ ions under reducing conditions can exceed that of Ce4+, no signs of Ce4+ reduction were detected in BaFe1−xCexO3−δ under the same conditions. A negative influence of cerium substitution for iron on electrical conductivity was detected. The oxygen-ion conductivity of the x = 0.05 composition at 950 °C was found to be as high as 0.358 ± 0.002 S·cm−1, whereas the ion conductivity of the oxide with x = 0.10 was only 0.041 ± 0.001 S·cm−1. Such a strong suppression of oxygen transport is argued to be the result of a local lattice strain caused by a considerable difference between the sizes of cerium and iron ions. The unfavorable impact of cerium in BaFe1−xCexO3−δ on n- and p-type conductivity is attributed to its impeding role in the Fe–O–Fe electron transport network. [ABSTRACT FROM AUTHOR]

Lead contamination in water poses significant health risks, making its removal imperative. In this study, magnetic strontium ferrite (SrFe12O19) nanoparticles were facilely synthesized by the Pechini sol–gel method and subsequently functionalized with a novel chitosan–Schiff base ligand to obtain a novel inorganic/organic nanocomposite for removing Pb(II) ions from aqueous solutions. The chitosan–Schiff base ligand was synthesized through the reaction of chitosan with 2,4,5-trihydroxybenzaldehyde. The presence of two X-ray diffraction (XRD) peaks at 2Ɵ = 10.5° and 2Ɵ = 20.5°, alongside the characteristic SrFe12O19 peaks, confirmed the functionalization of the nanoparticles with the ligand. Additionally, a significant decrease in the saturation magnetization value from 40.29 emu/g in pure SrFe12O19 nanoparticles to 17.32 emu/g in the nanocomposite further verified the functionalization. The presence of carbon (C) and nitrogen (N) atoms in the energy-dispersive X-ray (EDX) pattern of the nanocomposite, in addition to iron (Fe), strontium (Sr), and oxygen (O), also confirmed the functionalization. The nanocomposite's maximum adsorption capacity for Pb(II) ions was 390.63 mg/g. Moreover, the adsorption process is endothermic, spontaneous, and chemical, occurring via complexation with -C=N and -OH groups, and it fits well with the Langmuir equilibrium isotherm and the pseudo-second-order kinetic equation. [ABSTRACT FROM AUTHOR]

In the present paper, composite thin films of barium strontium titanate (BaxSr1−xTiO3) with an acceptor modifier (magnesium oxide—MgO) were deposited on metal substrates (stainless steel type) using the sol–gel method. The composite thin films feature BaxSr1−xTiO3 ferroelectric solid solution as the matrix and MgO linear dielectric as the reinforcement, with MgO concentrations ranging from 1 to 5 mol%. Following thermal treatment at 650 °C, the films were analyzed for their impedance response. Experimental impedance spectra were modeled using the Kohlrausch–Williams–Watts function, revealing stretching parameters (β) in the range of approximately 0.78 to 0.89 and 0.56 to 0.90 for impedance and electric modulus formalisms, respectively. Notably, films modified with 3 mol% MgO exhibited the least stretched relaxation function. Employing the electric equivalent circuit method for data analysis, the "circle fit" analysis demonstrated an increase in capacitance from 2.97 × 10−12 F to 5.78 × 10−10 F with the incorporation of 3 mol% MgO into BST-based thin films. Further analysis based on Voigt, Maxwell, and ladder circuits revealed trends in resistance and capacitance components with varying MgO contents, suggesting non-Debye-type relaxation phenomena across all tested samples. [ABSTRACT FROM AUTHOR]

M-type hexagonal ferrites were produced using the citrate auto-combustion technique. To understand the effects of substituting divalent Co2+ and rare earth elements Dy3+ on the structure, magnetic and removal efficiency of hexagonal ferrites, a series of samples including SrFe12O19, SrFe11.5Co0.5O19, Sr0.95Dy0.05Fe12O19, Sr0.95Dy0.05Fe11.5Co0.5O19 were analyzed. XRD analysis showed that all samples crystallized into a single M-type hexagonal phase. The small wavenumber absorption bands between 400 and 1000 cm−1 in FTIR curves are the primary features of M-type hexagonal ferrites. Magnetic properties varied with the addition or removal of Dy3+ and Co2+ doping due to the impact of spin canting with Dy3+ and Co2+ ions on strontium and iron ions. The study aimed to gather information about doping magnetic hexaferrites, which could be a pioneering development in wastewater treatment. The study examined the impact of substitution with rare earth and divalent elements in wastewater treatment, along with potential future developments in this field. The study examined various factors affecting the adsorption of lead ions from aqueous solutions, such as pH and contact time. The maximum removal efficiency of Sr0.95Dy0.05Fe11.5Co0.5O19 was approximately 99.6% at pH 7 and 25 °C after 60 min. The isotherm data fit into the Frendlish isotherm approach. The pseudo-first-order, pseudo-second-order, and intraparticle diffusion models clarified the adsorption kinetics. The capacity for adsorption of the studied samples was consistent and demonstrated through 4 cycles. [ABSTRACT FROM AUTHOR]

In the field of crop research, the study of roots involves many challenges, particularly the lack of effective methods for identifying crop roots. To deal with this problem, this study proposes a solution strategy: in applying strontium to crop leaves, the roots of different crops are distinguished. In this study, we applied strontium ions to the leaves of hydroponically grown wheat, and these strontium ions were partially absorbed by the leaves and transported to the roots. Therefore, the strontium concentration of roots was significantly increased through the foliar application of strontium. After mixing the treated wheat with the untreated wheat root, the greater the biomass of the wheat root applied with strontium ions, the higher the strontium concentration in the mixed root. Based on this phenomenon, we can establish the relationship between wheat root biomass and strontium concentration in mixed roots through linear fitting. Furthermore, we can also use the relationship between root biomass and root length to establish the correlation between strontium concentration in mixed roots and the root length of wheat with strontium ions. After measuring the strontium concentration of the mixed roots to be distinguished, the root biomass and root length of wheat applied with strontium ions can be calculated according to the equation obtained through linear fitting. The accuracy of this method was verified through a comparison with the actual value and the existing root staining method. The results show that the coefficient of determination (R2) of the root biomass estimation equation obtained through linear fitting reached 0.83, which is statistically significant (p < 0.01). The Pearson correlation coefficient with the measured value was more than 0.9, showing a very high correlation and significance. The root length estimation equation derived from the relationship between the root biomass, strontium concentration and root length was compared with the real root length value and the root length value obtained using the staining method. The Pearson correlation coefficient also exceeded 0.8 and reached a statistically significant level (p < 0.01). This study confirms that strontium ions can be absorbed and transported to roots through wheat leaves and successfully developed a new method for predicting the length of wheat roots, providing an effective new tool for wheat root research. [ABSTRACT FROM AUTHOR]

The structure, oxygen non-stoichiometry, thermomechanical and electrical properties of perovskite-type BaFe1−xCexO3−δ (x = 0.05, 0.10, 0.15) were studied in the light of the potential use of these oxides as electrode materials of solid oxide fuel cells. Partial substitution of iron by cerium in barium ferrite was shown to stimulate water incorporation into oxygen vacancies. This phenomenon is manifested by dehydration during heating, which is clearly registered by thermogravimetric and dilatometric measurements. Different behavior of cerium ions residing in the A- and B-sublattices of perovskite-type ferrites was revealed. In contrast to Sr1−xCexFeO3−δ oxide series, in which the concentration of Ce3+ ions under reducing conditions can exceed that of Ce4+, no signs of Ce4+ reduction were detected in BaFe1−xCexO3−δ under the same conditions. A negative influence of cerium substitution for iron on electrical conductivity was detected. The oxygen-ion conductivity of the x = 0.05 composition at 950 °C was found to be as high as 0.358 ± 0.002 S·cm−1, whereas the ion conductivity of the oxide with x = 0.10 was only 0.041 ± 0.001 S·cm−1. Such a strong suppression of oxygen transport is argued to be the result of a local lattice strain caused by a considerable difference between the sizes of cerium and iron ions. The unfavorable impact of cerium in BaFe1−xCexO3−δ on n- and p-type conductivity is attributed to its impeding role in the Fe–O–Fe electron transport network. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The photocatalytic oxidative coupling of thiols is one of the most popular methods to synthesize the disulfides. Triphenylamine and its derivatives (TPAs) are promising for the above reaction, but suffer from the easy polymerization and difficult separation. To overcome these obstacles while controlling the photogenerated electrons transfer directly to target substrates, herein, we constructed one TPA‐based metal‐organic framework (MOF), (Me2NH2)[Sr(TCBPA)]·DMA·3H2O (1), by direct self‐assembly of tris(4′‐carboxybiphenyl)amine (H3TCBPA) and photoredox inert strontium ion (Sr2+). DFT calculations revealed that the valence band maximum (VBM) and the conduction band minimum (CBM) are mainly located on TCBPA3–, successfully inhibiting the undesirable electron migration to metal nodes. Experimental results indicated that 1 displays superior performance than homogeneous H3TCBPA, which may result from the abundant π···π and C—H···π interactions between the well‐arranged TCBPA3– and the build‐in electric field between the anionic framework and the Me2NH2+. This work highlights that immobilizing TPAs into MOFs is one promising approach to designing heterogeneous photocatalysts for the synthesis of disulfides by oxidative coupling of thiols. [ABSTRACT FROM AUTHOR]

There is growing demand for separation of 90Y carrier free from 90Sr coexisting to produce high purity 90Y essential for radiopharmaceutical uses. Thus, in this context the sorption profiles of Y3+ and Sr2+ from aqueous solutions containing diethylenetriaminepenta acetic acid (DTPA), ethylenediaminetetra-acetic acid (EDTA), acetic acid, citric acid, or NaCl onto Chelex-100 (anion ion exchange) solid sorbent were critically studied for developing an efficient and low-cost methodology for selective separation of Y3+ from Sr2+ ions (1.0 × 10−5 M). Batch experiments displayed relative chemical extraction percentage (98 ± 5.4%) of Y3+ from aqueous acetic acid solution onto Chelex-100 (anion ion exchanger), whereas Sr2+ species showed no sorption. Hence, a selective separation of Y3+ from its parent 90Sr2+ has been established based upon percolation of the aqueous solution of Y3+ and Sr2+ ions containing acetic acid at pH 1-2 through Chelex-100 sorbent packed column at a 2 mL min−1 flow rate. Y3+ species were retained quantitatively while Sr2+ ions were not sorbed and passed through the sorbent packed column without extraction. The sorbed Y3+ species were then recovered from the sorbent packed column with HNO3 (1.0 M) at a 1.0 mL min−1 flow rate. A dual extraction mechanism comprising absorption associated to "weak-base anion exchanger" and "solvent extraction" of Y3+ as (YCl6)3− and an extra part for "surface adsorption" of Y3+ by the sorbent is proposed. The established method was validated by measuring the radiochemical (99.2 ± 2 1%), radionuclide purity and retardation factor ( R f = 10.0 ± 0.1 cm) of 90Y3+ recovered in the eluate. Ultimately, the sorbent packed column also presented high stability for reusing 2-3 cycles without drop in its efficiency (±5%) towards Y3+ uptake and relative chemical recovery. A proposed flow sheet describing the analytical procedures for the separation of 90Y3+ from 90Sr2+ using chelating Chelex 100 (anion exchange) packed column is also included. [ABSTRACT FROM AUTHOR]

A series of novel phosphors, specifically Eu3+-doped and Eu3+/M+ co-doped (M = Li+, Na+, K+) SrLaNaTeO 6 , were synthesized via a high-temperature solid-state process. The luminous properties and thermal stability of these phosphors were thoroughly investigated. When subjected to the appropriate excitation wavelengths (395 and 465 nm), all phosphors demonstrate a pronounced red light emission, corresponding to the 5D 0 →7F 2 transition of Eu3+. The researchers found that the most effective concentration of Eu3+ doping in the Sr 1-x LaNaTeO 6 :xEu3+ phosphor was discovered to be x = 0.25. It was shown that excessive doping leads to concentration quenching, which can be attributed to the energy transfer interaction between Eu3+ ions. The incorporation of Li+, Na+, and K+ as charge compensation ions in conjunction with Eu3+ in Sr 0.75 LaNaTeO 6 :0.25Eu3+ phosphor leads to a notable enhancement in light intensity. Notably, the phosphor co-doped with Na+ exhibits the highest luminous intensity among the alkali metal charge compensation ions. The near proximity of the ion radius of the charge compensation ion Na+ to that of Sr2+ in the host facilitates the occupation of the Na + ion in the Sr2+ lattice location. Sodium ions (Na+) have the ability to counteract the positive defects resulting from the substitution of europium ions (Eu3+) with strontium ions (Sr2+), hence maintaining charge neutrality. Additionally, it should be noted that Sr 0.5 LaNaTeO 6 :0.25Eu3+,0.25Na+ phosphor exhibits a remarkable quantum yield of 71.26 % and lacks thermal quenching. These characteristics suggest that this particular phosphor holds promising potential for utilization in developing white-light-emitting diodes. This research adopted a strategy on alkali metal ions (Li+, Na+, K+) as charge compensators to improve luminescence properties and quantum yield of phosphor. Li+, Na+, K+ co-doped significantly improve the luminescence intensity of phosphor. Meanwhile, this phosphor exhibits excellent thermal stability and a strong negative thermal quenching. Significantly, Sr 0.5 LaNaTeO 6 :0.25Eu3+,0.25Na+ phosphor demonstrates excellent color purity (98.6 %) and quantum yield (71.26 %). [Display omitted] • Alkali metal charge compensation ions Li+, Na+ and K+ co-doped significantly improve the luminescence intensity of Sr 1-x LaNaTeO 6 :xEu3+ phosphor. • A series of Sr 0.5 LaNaTeO 6 :0.25Eu3+,0.25M+ (M+ = Li+, Na+, K+) red-emitting phosphor has remarkable negative thermal quenching. • Sr 0.5 LaNaTeO 6 :0.25Eu3+,0.25Na+ phosphor demonstrates excellent quantum yield (71.26 %) and color purity (98.6 %). [ABSTRACT FROM AUTHOR]

The incorporation of crown ether into metal‐organic frameworks (MOFs) is garnered significant attention because these macrocyclic units can fine‐tune the inherent properties of the frameworks. However, the synthesis of flexible crown ethers with precise structures as the fundamental building blocks of crystalline MOFs remains a challenging endeavor, with only a limited number of transition metal examples existing to date. Herein, 18‐crown‐6 and 24‐crown‐8 struts are successfully incorporated into the skeleton of zirconium‐based MOFs to obtain two new and stable crown ether‐based MOFs, denoted as ZJU‐X100 and ZJU‐X102. These newly developed MOFs displayed high porosity and remarkable stability when exposed to various solvents, boiling water, pH values, and even concentrated HCl conditions. Thanks to their highly ordered porous structure and high‐density embedding of specific binding sites within tubular channels, these two MOFs exhibited extremely fast sorption kinetics and demonstrated outstanding performance in the uptake of strontium and cesium ions, respectively. Furthermore, the structures of Sr‐adsorbed ZJU‐X100 and Cs‐adsorbed ZJU‐X102 are solved and confirmed the precise location of Sr2+/Cs+ in the cavity of 18‐crown‐6/24‐crown‐8. This makes modular mosaic of different crown ethers into the skeleton of stable zirconium‐based MOFs possible and promote such materials have broad applications in sorption, sensing, and catalysis. [ABSTRACT FROM AUTHOR]

Titanium has broad application prospects in the field of hard bone tissue repair and replacement due to its low density, an elastic modulus similar to that of human bone, and better biocompatibility than stainless steel and cobalt-based alloys. However, titanium is a biologically inert material with low biological activity. After implantation, it only physically bonds with bone instead of chemically bonding, which causes complications such as implant loosening. In this study, a strontiumdoped titanium dioxide coating was prepared on a titanium surface with micro-arc oxidation. Based on a systematic study of the surface properties of the strontiumdoped titanium dioxide coating, the biocompatibility and bioactivity of the coating were evaluated with in vitro cell experiments. The results showed that the strontium-doped titanium dioxide coating was successfully prepared on the titanium surface and exhibited strong bonding with the substrate. The coating surface had a porous structure, and the strontium was dispersed on the surface and inside the coating. The strontium ions were released slowly, which improved the corrosion and wear resistance of the titanium. In vitro cell experiments showed that the coating had good cell compatibility; it promoted the adhesion, proliferation and differentiation of MC3T3-E1 cells and exhibited good biological activity. These results showed that preparation of a strontium-doped titanium dioxide coating by micro-arc oxidation is feasible. The coating had a good surface morphology, improved the biological activity of the titanium and has good potential for clinical application. [ABSTRACT FROM AUTHOR]

Synthesis of solar thermochemical hydrogen (STCH) production redox materials with engineered structures, for example, replica foams, can enable efficient heat and mass transport and are critical for scaled-up systems. Prior work has motivated the use of lanthanum strontium manganese (LSM)-type perovskites as foamed STCH materials, but the effect of their morphology on bulk and kinetic behavior has not been reported. In this work, replica and direct foamed samples of La0.65Sr0.35MnO3-δ (LSM35) were fabricated and compared to synthesized powders and dense monoliths, and similarly synthesized CeO2-δ (ceria) foams, regarding their specific reaction rates and bulk oxygen capacity/H2 yields. Changes in oxygen capacity (δδ) and reaction rates were measured between 1200 °C and 1400 °C by using fixed ratios of steam and hydrogen during both reduction and oxidation steps, allowing for analysis under practical high conversion conditions. Results suggest bulk behavior and reaction rates of the foamed LSM materials are comparable to their powder analogues. Differences in reaction rates were observed only when replica foamed samples were subjected to rapid laser heating (emulating conditions expected in solar furnaces), which is expected but has not been demonstrated at such a small scale. Foamed samples were further subjected to 50 redox cycles at 1400 °C to evaluate their stability. Results show no statistically significant decrease in hydrogen production for any of the foamed samples, but the direct foamed samples became brittle with time. Together, these results demonstrate the viability of replica foamed LSM perovskites for integration in scaled-up STCH systems. [ABSTRACT FROM AUTHOR]

In this study, we used an improved "diffusion cell" method to precisely determine the diffusion-driven kinetic isotope fractionation factors of the Li, K, Rb, Mg, Ca, Sr, and Ba cations in aqueous solutions under room temperature. The obtained isotope fractionation factors (±2σ errors) are, α 7/6Li = 0.996139 ± 0.000140, α 41/39K = 0.998572 ± 0.000072, α 87/85Rb = 0.999333 ± 0.000020, α 26/24Mg = 0.999877 ± 0.000010, α 44/42Ca = 0.999704 ± 0.000010, α 88/86Sr = 0.999781 ± 0.000014, α 138/135Ba = 0.999716 ± 0.000018. The results show that the charge of the cation and the ion-water bond length for the aquo ions are the two predominant factors affecting the mass dependence of isotope fractionation (β factor) during cation diffusion in aqueous solutions. Cations with higher charge numbers and shorter ion-water bond lengths exhibit less kinetic isotope fractionation during diffusion. Therefore, the isotope separation effect during diffusion (or β factor) in fluids is fundamentally controlled by the intensity of ion-water interaction. Weaker ion-water interaction (e.g., lower charge number, longer ion-water bond length) leads to less prominent hydrodynamic behavior for diffusing ions at the molecular level, thus more significant isotope fractionation in bulk solutions, and vice versa. Ions of larger radius would show stronger mass dependence of isotope fractionation (β factor), which can cancel the effect of decreasing relative isotope mass difference for heavier elements, thus kinetic isotope fractionation during diffusion in aqueous solutions remains prominent even for heavy elements such as Rb, Sr, and Ba. The diffusion-driven kinetic isotope fractionation factors measured in this study could provide a useful basis for interpreting specific natural isotopic variability of alkaline and alkaline-earth elements in supergene environments where chemical diffusion takes place. [ABSTRACT FROM AUTHOR]

Osteoporosis stands out as a prevalent skeletal ailment, prompting exploration into potential treatments, including dietary strontium ion supplements. This study assessed the efficacy of supplementation of three strontium forms—strontium citrate (SrC), strontium ranelate (SrR), and strontium chloride (SrCl)—for enhancing bone structure in 50 female SWISS mice, aged seven weeks. In total, 40 mice underwent ovariectomy, while 10 underwent sham ovariectomy. Ovariectomized (OVX) mice were randomly assigned to the following groups: OVX (no supplementation), OVX + SrR, OVX + SrC, and OVX + SrCl, at concentrations equivalent to the molar amount of strontium. After 16 weeks, micro-CT examined trabeculae and cortical bones, and whole-bone strontium content was determined. Results confirm strontium administration increased bone tissue mineral density (TMD) and Sr content, with SrC exhibiting the weakest effect. Femur morphometry showed limited Sr impact, especially in the OVX + SrC group. This research highlights strontium's potential in bone health, emphasizing variations in efficacy among its forms. [ABSTRACT FROM AUTHOR]

BACKGROUND: Wastewater containing m‐cresol has become a global water environmental problem because its degradation is difficult, and it is highly toxic to plants, animals, and humans. The heterogeneous catalytic ozonation process has been widely used in the treatment of environmental pollution, so it is very important to study efficient catalysts. Perovskite catalysts have been widely investigated and applied in catalytic ozonation processes. Among them, strontium zirconate is a promising perovskite catalyst owing to its high oxidation efficiency and environmental friendliness. RESULTS: Strontium zirconate was successfully synthesized via the co‐precipitation method. To improve strontium zirconate catalytic performance, some methods such as changing the doping ratio of cobalt and iron, changing the amount of polyethylene glycol added, changing the calcination temperature, and changing the aging time were carried out during the synthesis process. Finally, the optimal conditions were determined. 0.4 g L−1 Sr2Co0.4Fe0.6ZrO6 prepared under the optimal conditions was used for catalytic ozonation of 100 ppm m‐cresol, which achieved the optimum degradation (0.136 min−1), m‐cresol conversion rate (92.2%) and total organic carbon removal rate (12.1%) within 20 min. CONCLUSION: This work provides the best preparation conditions. The Sr2Co0.4Fe0.6ZrO6 catalyst, as prepared, is the optimal catalyst for catalytic ozonation of m‐cresol among the investigated Sr2CoxFe1−xZrO6 catalysts. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The ionic properties of strontium (Sr), a significant artificial radionuclide in the marine environment, were estimated using a stable nuclide-substituting experimental system under controlled laboratory conditions. The bio-accumulation of Sr and its impacts, as well as any possible hidden mechanisms, were evaluated based on the physiological alterations of the sentinel blue mussel Mytilus edulis. The mussels were exposed to a series of stress-inducing concentrations, with the highest solubility being 0.2 g/L. No acute lethality was observed during the experiment, but sublethal damage was evident. Sr accumulated in a tissue-specific way, and hemolymph was the target, with the highest accumulating concentration being 64.46 µg/g wet weight (ww). At the molecular level, increases in the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and changes in ROS components (H2O2, O2−, and -OH) and antioxidant system activity indicated that the redox equilibrium state in hemocytes was disturbed. Furthermore, the rise in the hemocyte micronucleus (MN) rate (4‰ in the high-concentration group) implied DNA damage. At the cellular level, the structures of hemocytes were damaged, especially with respect to lysosomes, which play a crucial role in phagocytosis. Lysosomal membrane stability (LMS) was also affected, and both acid phosphatase (ACP) and alkaline phosphatase (AKP) activities were reduced, resulting in a significant decline in phagocytosis. The hemolymph population structure at the organ level was disturbed, with large changes in hemocyte number and mortality rate, along with changes in component ratios. These toxic effects were evaluated by employing the adverse outcome pathway (AOP) framework. The results suggested that the disruption of intracellular redox homeostasis is a possible explanation for Sr-induced toxicity in M. edulis. [ABSTRACT FROM AUTHOR]

The construction of nuclear power plants necessitates careful consideration of the discharge and fixation of nuclear waste. Geopolymers are new cement-based materials (CBMs) with three-dimensional cage-like structures that enable effective nuclear waste fixation. In this work, the adsorption of radioactive caesium and strontium ions by sodium aluminosilicate hydrate (NASH) gel, the main component of geopolymers, was investigated using molecular dynamics simulations to obtain nanoscale insights into the ions' interactions with the gel. The formation of strong ion–oxygen bonds allowed both ions to be effectively adsorbed on the NASH surface, but the adsorption ratio of strontium ions (17.2%) was slightly lower than that of caesium ions (21.0%). Because strontium ions are divalent, they can form stronger electrostatic interactions with water molecules and chloride ions, which hinders their approach to the interface. For the same reason, the diffusion coefficient of strontium ions in solution is lower than that of caesium ions. These results provide new insights into the nuclear waste fixation capacity of NASH gel and guidance for the design of new CBMs for radioactive waste disposal. [ABSTRACT FROM AUTHOR]