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The radionuclides of cesium (Cs) and strontium (Sr) are dangerous products of nuclear fission that can be accidentally released into wastewater. In the present work, the capacity of thermally treated natural zeolite (NZ) from Macicasu (Romania) to remove Cs+ and Sr2+ ions from aqueous solutions in batch mode was investigated by contacting different zeolite quantities (0.5, 1, and 2 g) of 0.5–1.25 mm (NZ1) and 0.1–0.5 mm (NZ2) particle size fractions with 50 mL working solutions of Cs+ and Sr2+ (10, 50, and 100 mg L−1 initial concentrations) for 180 min. The concentration of Cs in the aqueous solutions was determined by inductively coupled plasma mass spectrometry (ICP-MS), whereas the Sr concentration was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The removal efficiency of Cs+ varied between 62.8 and 99.3%, whereas Sr2+ ranged between 51.3 and 94.5%, depending on the initial concentrations, the contact time, the amount, and particle size of the adsorbent material. The sorption of Cs+ and Sr2+ was analyzed using the nonlinear form of Langmuir and Freundlich isotherm models and pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. The results indicated that the sorption kinetics of Cs+ and Sr2+ on thermally treated natural zeolite was described by the PSO kinetic model. Chemisorption dominates the retention of both Cs+ and Sr2+ by strong coordinate bonds with an aluminosilicate zeolite skeleton. [ABSTRACT FROM AUTHOR]

Herein, the effects of different Sr content doping on the crystal structure and electronic structure of La1−xSrxFeO3−δ (LSFO‐x, x = 0, 0.2, 0.5, 0.8, 1.0) are studied by X‐ray diffraction (XRD) and Mössbauer spectroscopy. It is shown in the XRD results that the structure of LSFO‐x changes from orthorhombic (Pnma [#62]) to cubic (Pm‐3m (#221)) to tetragonal (I4/mmm (#139)) with increasing strontium doping. It is shown in Mössbauer spectrum analysis that with the gradual increase of Sr doping, iron ions finally change from +3 oxidation state to +4 oxidation state after passing through an intermediate oxidation state of +3.5. The Fe3.5+ state can result from rapid electron exchange (Fe3+ + Fe4+ ⇋ Fe4+ + Fe3+) between iron ions of different oxidation states within the crystal structure; the study provides some reference for future research to study the effect of iron‐oxidation state on the specific activity of strontium‐doped LaFeO3. [ABSTRACT FROM AUTHOR]

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Strontium, the main component of radioactive nuclear wastewater, is characterized by a high fission yield and an extended half-life. It is easily absorbed by the human body, thus greatly threatening the environment and the human body. In this study, a mesoporous composite phase sodium superionic conductor (NVP@NMP) was synthesized by the droplet template method, and the rapid capture of Sr2+ from wastewater was achieved by constructing a nano-heterogeneous interface to increase the ion diffusion rate. NVP@NMP showed efficient and rapid removal of strontium ions in adsorption kinetics, isothermal adsorption, solution pH, and interfering ions concentration tests, especially using the equilibrium time of 2 min for strontium absorption by NVP@NMP and a maximum theoretical adsorption capacity of 361.36 mg/g. The adsorption process was spontaneous, endothermic, and feasible. At higher concentrations of other competing ions (Na, K, Ca, Mg, and Cs), the adsorbent exhibited higher selectivity towards Sr2+.TEM, XPS, and XRD analyses revealed that ion exchange was the main mechanism for the NVP@NMP ultrafast adsorption of Sr2+. In this research, we investigated the feasibility of ultrafast strontium capture by sodium superionic conductor structured phosphates and explained the ultrafast strontium adsorption mechanism of NASICON materials through XPS. [ABSTRACT FROM AUTHOR]

Ginkgo biloba (Ginkgo)/calcium silicate nanocomposite (NG-CSA) was prepared as a novel sorbent. Nanomaterial was characterized using different techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, differential thermal analysis and thermal gravimetric analysis (DTA and TG). Adsorption of Sr(II) and Cd(II) ions was performed taking into account significant parameters such as initial pH of the solution, shaking time and initial concentration of metal ions as well as temperature. The acquired results were disclosed that the adsorption of both ions is notably improved using NG-CSA composite. The monolayer capacity of NG-CSA for Sr(II) and Cd(II) from binary system is 122.45 and 64.68 mg/g for Sr(II) and Cd(II), respectively. The kinetic studies exposed that the adsorption process followed nonlinear pseudo-first-order model. The isotherm studies show that the extended Langmuir model is more applicable than Freundlich model for binary system adsorption process. The value of diffusion coefficient for the Sr(II) and Cd(II) is in range 10−10 m2/s which indicates the chemisorption nature of the process. The maximum value of desorption for the Sr(II) and Cd(II) is 98.41% and 97.66 utilized 0.3 M of nitric acid. This indicated that NG-CSA composite can be regenerated and reused for further adsorption of Sr(II) and Cd(II) from wastewater. [ABSTRACT FROM AUTHOR]

Most of our knowledge of past seawater temperature history is based on δ18 O values of calcium carbonate fossil shells. However, the determination of past temperatures using this proxy requires the knowledge of past seawater δ18 O values, which is generally poorly constrained. Other paleothermometers using carbonate archives, such as Mg/Ca ratios and clumped isotopes (Δ47), have been developed to allow for paleotemperatures to be estimated independently and to allow past ocean δ18 O values to be calculated using various groups of calcifying organisms. Articulated brachiopod shells are some of the most commonly used archives in studies of past oceanic geochemistry and temperature. They are abundant in the fossil record since the Cambrian, and for decades, their low Mg–calcite mineralogy has been considered relatively resistant to diagenetic alteration. Here, we investigate the potential of brachiopod shells as recorders of seawater temperatures and seawater δ18 O values using new brachiopod shell geochemical data by testing multiple well-established or suggested paleothermometers applied to carbonate archives. Modern articulated brachiopod shells covering a wide range of temperatures (-1.9 to 25.5 ∘ C), depths (5 to 3431 m) and salinities (33.4 to 37.0 PSU) were analysed for their stable isotope compositions (δ13 C, δ18 O and Δ47) and their elemental ratios (Mg/Ca , Sr/Ca , Na/Ca and Li/Ca). Our data allowed us to propose a revised oxygen isotope fractionation equation between modern-brachiopod shell calcite and seawater: T = - 5.0 (± 0.2) (δ 18 O c - δ 18 O sw) + 19.4 (± 0.4) , where δ18 O c is in ‰ VPDB, δ18 O sw is in ‰ VSMOW, and T is in ∘ C. Our results strongly support the use of clumped isotopes as an alternative temperature proxy but confirm significant offsets relative to the canonical relationship established for other biogenic and abiogenic calcium carbonate minerals. Brachiopod shell Mg/Ca ratios show no relationship with seawater temperatures, indicating that this ratio is a poor recorder of past changes in temperatures, an observation at variance with several previous studies. Despite significant correlations with brachiopod living temperature, brachiopod shell Sr/Ca , Na/Ca and Li/Ca values indicate the influence of environmental and biological factors unrelated to temperature, which undermines their potential as alternative temperature proxies. Kinetic effects (growth rates) could explain most of the deviation of brachiopod shell calcite from expected isotopic equilibrium with seawater and part of the distribution of Sr/Ca , Na/Ca and Li/Ca ratios. [ABSTRACT FROM AUTHOR]

We have investigated the structural and magnetic properties of strontium (Sr2+) substituted polycrystalline doubly-ordered perovskite Y2−xSrxNiMnO6 (x = 0, 0.05, 0.1), characterized with X-ray diffraction, X-ray photoelectron spectroscopy, dc-magnetization, and frequency-dependent linear ac-susceptibility measurements. The undoped Y2NiMnO6 is observed with traces of YMnO3 and NiO as secondary phases, whereas the phase purity improved with Sr2+ substitution. The XRD patterns of Y2−xSrxNiMnO6 (x = 0, 0.05, 0.1) are fitted with the Rietveld refinement in a monoclinic (P21/n) space-group symmetry and the secondary phases YMnO3 and NiO are fitted in hexagonal (P63cm) and cubic (Fm3m) space groups, respectively. The structural modifications observed with Sr2+ substitution manifest in octahedral distortion, altered lattice parameters, average bond-length, bond angles, tolerance factor, and corresponding electron bandwidths. The XPS study confirms the presence of Jahn-Teller (JT-active) species (Ni3+, Mn3+) along with Ni2+, Mn4+ ions. Increasing Sr2+ concentration triggers the paramagnetic (PM) to ferromagnetic (FM) transition spontaneously, along with increased transition temperature (Tc). The thermomagnetic study in field cooled/zero-field cooled modes and linear ac-susceptibility measurements suggest that the investigated compounds exhibit nonspontaneous and cumulative magnetic domain-wall dynamics to attain FM-state with glassy-type behavior toward lower temperatures. [ABSTRACT FROM AUTHOR]

Calcium-aluminum-rich inclusions (CAIs) in chondrite meteorites are the oldest rocks in the Solar System and were formed by condensation from nebular gas. Recent mass spectrometric measurements have revealed that CAIs possess nucleosynthetic isotopic compositions different from those of terrestrial materials for various elements, indicating a heterogeneous distribution of nuclides from various stellar sources in the early Solar System. CAIs are classified into coarse-grained (CGs) and fine-grained (FGs) inclusions. The former have experienced secondary melting through thermal events after their formation, while the latter evidently avoided the remelting. Thus, FGs are considered to be direct condensates from a high-temperature gas, making them ideal for the investigation of the origin and formation process of CAIs. In this study, the elemental abundances and Sr isotopic compositions in eight FGs from a carbonaceous chondrite Allende were analyzed by utilizing a micromilling technique. These FG samples were found to have rare-earth element (REE) patterns reflecting various degrees of elemental fractionation and variable µ84Sr values ranging from 61 to 844 ppm. It cannot be ruled out that matrix contamination during micromilling or secondary alteration on the Allende parent body has affected the elemental abundances and µ84Sr values observed in FGs to some extent; however, the large variation in µ84Sr values could reflect the variability in the FG formation processes. Importantly, REE-fractionated FGs, which were depleted in heavy REEs relative to light REEs, had relatively high µ84Sr values. This suggests that the formation of REE-fractionated FGs was triggered by rapid heating events, such as FU Orionis that occurred periodically in the early Solar System, and that at least two different heating events probably formed FGs with two different µ84Sr values. [ABSTRACT FROM AUTHOR]

Calcite (CaCO 3) composition and properties are defined by the chemical environment in which CaCO 3 forms. However, a complete understanding of the relationship between aqueous chemistry during calcite precipitation and resulting chemical and physical CaCO 3 properties remains elusive; therefore, we present an investigation into the coupled effects of divalent cations Sr2+ and Mg2+ on CaCO 3 precipitation and subsequent crystal growth. Through chemical analysis of the aqueous phases and microscopy of the resulting calcite phases in compliment with density functional theory calculations, we elucidate the relationship between crystal growth and the resulting composition (elemental and isotopic) of calcite. The results of this experimental and modeling work suggest that Mg2+ and Sr2+ have cation-specific impacts that inhibit calcite crystal growth, including: (1) Sr2+ incorporates more readily into calcite than Mg2+ (D Sr > D Mg), and increasing [Sr2+] t or [Mg2+] t increases D Sr ; (2) the inclusion of Mg2+ into structure leads to a reduction in the calcite unit cell volume, whereas Sr2+ leads to an expansion; (3) the inclusion of both Mg2+ and Sr2+ results in a distribution of unit cell impacts based on the relative positions of the Sr2+ and Mg2+ in the lattice. These experiments were conducted at saturation indices of CaCO 3 of ∼4.1, favoring rapid precipitation. This rapid precipitation resulted in observed Sr isotope fractionation confirming Sr isotopic fractionation is dependent upon the precipitation rate. We further note that the precipitation and growth of calcite favors the incorporation of the lighter 86Sr isotope over the heavier 87Sr isotope, regardless of the initial solution conditions, and the degree of fractionation increases with D Sr. In sum, these results demonstrate the impact of solution environment to influence the incorporation behavior and crystal growth behavior of calcite. These factors are important to understand in order to effectively use geochemical signatures resulting from calcite precipitation or dissolution to gain specific information. [ABSTRACT FROM AUTHOR]

This paper presents the results of wastewater treatment at a mining enterprise developing a complex ore deposit in the Murmansk region, Russia. The main pollutants are sulfate, manganese, and strontium. For this complex wastewater treatment, a two-stage scheme was proposed and tested using two sorbents (at a pH of 6): an aminated peat biosorbent to remove sulfate and a commercial sorbent based on the mineral brucite to remove metals. Optimal conditions were established for purifying the wastewater of sulfate and manganese and strontium ions to the level of maximum available concentrations in water bodies for fishery purposes. [ABSTRACT FROM AUTHOR]

Silica-based ceramics doped with calcium and magnesium have been proposed as suitable materials for scaffold fabrication. Akermanite (Ca2MgSi2O7) has attracted interest for bone regeneration due to its controllable biodegradation rate, improved mechanical properties, and high apatite-forming ability. Despite the profound advantages, ceramic scaffolds provide weak fracture resistance. The use of synthetic biopolymers such as poly(lactic-co-glycolic acid) (PLGA) as coating materials improves the mechanical performance of ceramic scaffolds and tailors their degradation rate. Moxifloxacin (MOX) is an antibiotic with antimicrobial activity against numerous aerobic and anaerobic bacteria. In this study, silica-based nanoparticles (NPs) enriched with calcium and magnesium, as well as copper and strontium ions that induce angiogenesis and osteogenesis, respectively, were incorporated into the PLGA coating. The aim was to produce composite akermanite/PLGA/NPs/MOX-loaded scaffolds through the foam replica technique combined with the sol–gel method to improve the overall effectiveness towards bone regeneration. The structural and physicochemical characterizations were evaluated. Their mechanical properties, apatite forming ability, degradation, pharmacokinetics, and hemocompatibility were also investigated. The addition of NPs improved the compressive strength, hemocompatibility, and in vitro degradation of the composite scaffolds, resulting in them keeping a 3D porous structure and a more prolonged release profile of MOX that makes them promising for bone regeneration applications. [ABSTRACT FROM AUTHOR]

In this study, magnetic (Fe3O4) nanobiocomposite were synthesized by a co-precipitation method using pectin biopolymer as a stabilizer. Nanobiocomposites were characterized via several characterization methods. The particle size and surface area of the nanobiocomposite were found as 5.76 nm 94.651 m2/g, respectively. The TEM and SEM results indicated that the spherical nanoparticles were well dispersed into the polymer matrix. Optimal adsorption parameters were determined using FFD. It was determined that pH and initial concentration are the main effects on the Sr(II) removal. Maximum sorption capacities according to D–R and Langmuir isotherms were determined as 0.018 mol/g and 26.455 mg/g, respectively. [ABSTRACT FROM AUTHOR]

In the Yan'an gas field, southeast of Ordos Basin, the discovered natural gas reserves are 114 billion cubic meters. Highly productive gas reservoirs were formed in paleokarst. By using 164 samples from 27cores, the geochemical study of diagenetic evolution was carried out, and the relationship between different diagenesis environments was discussed by using scanning electron microscopy, carbon and oxygen isotope, and isotopic and fluid inclusion microthermometric observations. Results show that the lithology of reservoir is anhydrite-bearing mud powder crystal dolomite, powder crystal dolomite, and karst breccia dolomite; the filling includes dolomite, calcite, anhydrite, quartz, fluorite, and clay minerals; δ13C (‰ PDB) value is between −6.31‰ and 1.01‰, δ18O (‰ PDB) value ranges from −11.36‰ to −6.54‰, and the 87Sr/86Sr value ranges from 0.7077 to 0.7081. The overall carbon isotope of Majiagou Formation decreases first and then increases, and the strontium isotope evolution curve generally increases first and then decreases, indicating that the water environment of Majiagou Formation experienced a relatively high salinity concentration period and a relative desalinization period during deposition. The stratigraphic development shows a cyclical trend, responding to the multistage transgression and regression process. The homogenization temperature of fluid inclusions is 70–100°C, salinity is 0–3.5%, homogenization temperature of fluid inclusions is 70–100°C, salinity is >3.5%, homogenization temperature of fluid inclusions is 100–160°C, salinity is 0–3.5%, homogenization temperature of fluid inclusions is 100–160°C, salinity is >3.5%, homogenization temperature of fluid inclusion temperature is 160–200°C, and salinity is >3.5%, indicating that the fluid source in the sedimentation and diagenesis process is seawater, atmospheric freshwater, hydrocarbon fluid, and deep thermal fluid. The diagenetic environments are divided into marine diagenetic environments, metric freshwater diagenetic environments, and burial diagenetic environments. [ABSTRACT FROM AUTHOR]

In order to reduce the loosening of dental implants, surface modification with hydroxyapatite (HA) coating has shown promising results. Therefore, in this present study, the sol-gel technique has been employed to form a tantalum and strontium ion-doped hybrid HA layer coating onto the titanium (Ti)-alloy substrate. In this study, the surface modification was completed by using 3% tantalum pent oxide (Ta2O5), 3% strontium (Sr), and a combination of 1.5% Ta2O5 and 1.5% Sr as additives, along with HA gel by spin coating technique. These additives played a prominent role in producing a porous structure layer coating and further cell growth. The MG63 cell culture assay results indicated that due to the incorporation of strontium ions along with tantalum embedded in HA, cell proliferation increased significantly after a 48 h study. Therefore, the present results, including microstructure, crystal structure, binding energy, and cell proliferation, showed that the additives 1.5% Ta2O5 and 1.5% Sr embedded in HA on the Ti–substrate had an optimized porous coating structure, which will enhance bone in-growth in surface-modified Ti-implants. This material had a proper porous morphology with a roughness profile, which may be suitable for tissue in-growth between a surface-modified textured implant and bone interface and could be applicable for dental implants. [ABSTRACT FROM AUTHOR]

This work reports the structural, vibrational and thermodynamic properties of the cluster ions SrI 3 − , S r 2 I 3 + , S r 3 I 5 + , S r 4 I 7 + and S r 5 I 9 + which were detected earlier in vapour over strontium diiodide at high temperatures ranging from 1000–1200 K. Three theoretical methods, DFT, MP2 and MP4 were used to compute the equilibrium geometrical properties, vibrational spectra and thermodynamic properties. Different geometrical structures were considered for the ions, it was observed that the ions SrI 3 − , S r 2 I 3 + , S r 3 I 5 + , and S r 5 I 9 + correspond to D3h point group and S r 4 I 7 + corresponds to C2v configuration. From the considered alternative structures for all ions, no isomers were identified. The results for the enthalpies of dissociation reactions, Δ r H o (0) and formation of the ions, Δ f H o (0) are respectively presented in kJ mol–1 as ( Δ r H o (0), Δ f H o (0)): 243.5 ± 4, -707 ± 04 ( SrI 3 − ); 294.5 ± 13, -45.6 ± 13 ( S r 2 I 3 + ); 267.1 ± 17, -588 ± 17 ( S r 3 I 5 + ); 239.4 ± 26, -1102 ± 26 ( S r 4 I 7 + ); and 214.0±21, -1591 ± 21 ( S r 5 I 9 + ). [ABSTRACT FROM AUTHOR]

One of the promising methods for process intensification for micromixing, co-precipitation, and crystallization in continuous reactors is the use of vigorous vortices. A combination of the high intensity of the kinetic energy input with the small volume of the micromixing volume allows to concentrate the energy dissipation rate up to 104 W/kg and more. As the embodiment of such an idea, four new types of microreactors with intensively swirled flows were created and studied as a tool for continuous co-precipitation and crystallization. A correlation between residence time and segregation index was found: the smaller residence time, the higher energy dissipation rate and better quality of micromixing. A method for the synthesis of oxides of a number of transition metals in microreactors with intensively swirled flows with subsequent thermal treatment of co-precipitation products has been developed. This method was used to obtain ensembles of nanosized particles of zirconium oxides, as well as calcium and strontium fluorides. In comparison with the currently widely used hydro- and solvothermal methods, the proposed method has high productivity (around 10 m3/day for lab scale device), can significantly reduce the duration of the process, provides low energy consumption, does not require a large number of labor-intensive operations, is technologically advanced and easily scalable. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is one of the most common chronic musculoskeletal diseases, which accounts for a large proportion of physical disabilities worldwide. Herein, we fabricated injectable gelatin/poly(L-lactide)-based nanofibrous microspheres (MS) via electrospraying technology, which were further modified with tannic acid (TA) named as TMS or metal phenolic networks (MPNs) consisting of TA and strontium ions (Sr2+) and named as TSMS to enhance their bioactivity for OA therapy. The TA-modified microspheres exhibited stable porous structure and anti-oxidative activity. Notably, TSMS showed a sustained release of TA as compared to TMS, which exhibited a burst release of TA. While all types of microspheres exhibited good cytocompatibility, TSMS displayed good anti-inflammatory properties with higher cell viability and cartilage-related extracellular matrix (ECM) secretion. The TSMS microspheres also showed less apoptosis of chondrocytes in the hydrogen peroxide (H 2 O 2)-induced inflammatory environment. The TSMS also inhibited the degradation of cartilage along with the considerable repair outcome in the papain-induced OA rabbit model in vivo as well as suppressed the expression level of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-1-beta (IL-1β). Taken together, TSMS may provide a highly desirable therapeutic option for intra-articular treatment of OA. Osteoarthritis (OA) is a chronic disease, which is caused by the inflammation of joint. Current treatments for OA achieve pain relief but hardly prevent or slow down the disease progression. Microspheres are at the forefront of drug delivery and tissue engineering applications, which can also be minimal-invasively injected into the joint. Polyphenols and therapeutic ions have been shown to be beneficial for the treatment of diseases related to the joints, including OA. Herein, we prepared gelatin/poly(L-lactide)-based nanofibrous microspheres (MS) via electrospinning incorporated electrospraying technology and functionalized them with the metal phenolic networks (MPNs) consisting of TA and strontium ions (Sr2+), and assessed their potential for OA therapy both in vitro and in vivo. [Display omitted] [ABSTRACT FROM AUTHOR]

The fate of radionuclides in the environment is attracting increased attention. The effect of various environmental effects on the adsorption behavior of the strontium ion (Sr2+) by red soil colloids in Southern China was studied by a series of batch experiments, and the adsorption mechanism was briefly investigated as well. With the increase in the solid–liquid ratio and the concentration of Sr2+, the adsorption efficiency increased gradually. The effect of pH and ionic strength on adsorption was strong, while temperature had little effect. The adsorption data fitted to the Langmuir model indicates that the process is monolayered and homogeneous. The thermodynamic parameters also show that the adsorption of Sr2+ on red soil colloids is a spontaneous and exothermic process. The aim of this work is to gain insight into the role of red soil colloids on the fate of radionuclides in the field. [ABSTRACT FROM AUTHOR]

The M-type hexagonal strontium ferrites substituted by Gd-Mn ions were synthesized by the sol-gel self-combustion method. The synthesized samples were researched by X-ray diffraction (XRD), Fourier transform infrared spectroscopy analysis (FT-IR), scanning electric microscopy (SEM), and vibrating sample magnetometer (VSM). The XRD and the FT-IR results show that the pure M-type hexagonal ferrites phase is successfully obtained in the samples with the substitution amount (x) from 0.00 to 0.09 of Gd-Mn. The VSM results show that, as the substitution amount (x) of Gd-Mn increases, the remanent magnetization (Mr) and saturation magnetization (Ms) of the Sr1-xGdxFe12-xMnxO19 gradually increase, and the maximum values of 39.53 emu/g and 23.73 emu/g were obtained when x = 0.09. When x continues to increase, Mr and Ms decrease slightly, but they are still higher compared with those of the unsubstituted one. The coercivity (Hc) of the samples after doping is much higher than the coercivity of the pure sample, but as the substitution amount x increases, the coercivity first increases and then decreases, while the maximum value of Hc is 6738 Oe at x = 0.06. [ABSTRACT FROM AUTHOR]

Divalent ions‐doping has recently been developed as a new approach to blue perovskite light emitting diodes (LEDs) with improved spectral stability. However, the efficiency of these perovskite LEDs, especially in the pure blue region, is still far behind their red‐ and green‐emissive counterparts. Here, a method to improve the device efficiency of strontium ion (Sr2+)‐doped pure blue perovskite LEDs, prominently by modifying the hole transport layer, is reported. Mixing a small amount of poly(9,9‐di‐n‐octylfluorene‐alt‐(1,4‐phenylene‐(4‐sec‐butylphenyl)imino)‐1,4‐phenylene) (TFB) into the hole transport layer poly(9‐vinylcarbazole) (PVK) remarkably improves the morphology and reduces the trap states of Sr2+‐doped perovskite films. As a result, a pure blue LED emitting at 470 nm is obtained and shows a high external quantum efficiency of 2.24% with stable electroluminescence spectra under a forward bias of up to 8 V, representing the best performance reported in the divalent ions‐doped pure blue perovskites so far. The work opens up the way for the development of efficient pure blue perovskite LEDs. [ABSTRACT FROM AUTHOR]

The aim of presented work was to synthesize the ecologically friendly sorbents using low cost reagents based on magnesium silicates by precipitation, hydrothermal and sol-gel methods. Morphology of materials obtained was investigated by means of thermogravimetric analysis (TG-DTA), low temperature adsorption/desorption method, scanning and transmission electron microscopic studies (SEM and TEM). It has been found that all sorbents are obtained in a form of amorphous layer-structure magnesium silicates with the micro-and mesoporous structure. Based on low temperature nitrogen isotherms, the specific surface area and volume of micropores calculated by the Brunauer-Emmet-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods were the greatest for the sample obtained by sol gel method (SBET = 640 m²/g, Vmicro = 0.26 cm³/g) while the sample synthesized by precipitation had the biggest volume of mesopores among the materials investigated (Vmeso = 0.39 cm³/g). As follows from TEM images, all samples consist of particles with the size from 10 up to 50 nm, the sample synthesized by sol gel method had the most homogeneous structure (MgSi-3). The ion exchange capacities of materials in the process of Cs+, Sr2+, Cu2+, and Co2+ removing from aqueous solution were determined and it was found that these properties depend on the method of materials obtaining. Data showed that magnesium silicate synthesized by precipitation method has the higher capacity toward the heavy metal cations compared to the radionuclides (1.56 and 0.96 mmol/g for cobalt and copper, respectively). For two samples synthesized by hydrothermal and sol-gel methods the increasing was fixed of capacity towards cesium and strontium ions that could be explained by the significant amounts of pores approx 2.6 nm radii in their structure. Experimental data were fitted to the Langmuir models. Analysing the data of adsorption studies, it was noted that all materials obtained can be used in adsorption technology for purification of water from heavy metal ions and radionuclides. [ABSTRACT FROM AUTHOR]

Drinking water contamination has become a worldwide problem due to the highly negative effects that pollutants can have on human organisms and the environment. Hydroxyapatite (HAp) has the appropriate properties for the immobilization of various pollutants, being considered amongst the most cost-effective materials for water decontamination. The main objective of this study was to use synthesized hydroxyapatite for the elimination of Sr2+ ions from contaminated solutions. The hydroxyapatite used in the decontamination process was synthesized in the laboratory using an adapted method. The hydroxyapatite powder (HAp) resulting from the synthesis was analyzed both before and after the elimination of Sr2+ ions from contaminated solutions. The efficiency of the HAp nanoparticles in removing Sr2+ ions from contaminated solution was determined by batch adsorption experiments. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to study the HAp samples before and after the removal of Sr2+ ions. The ability of HAp nanoparticles to eliminate strontium ions from contaminated solutions was established. Moreover, the removal of Sr2+ ions from the contaminated aqueous solutions was highlighted by ultrasound measurements. The value of the stability parameter calculated by ultrasonic measurements after the removal of Sr2+ ions from the contaminated solution was similar to that of double distilled water whose stability was used as reference. The outcomes of the batch experiments and the parameters obtained from Langmuir and Freundlich models indicated that the HAp nanoparticles had a strong affinity for the elimination of Sr2+ ions from polluted solutions. These results emphasized that HAp nanoparticles could be excellent candidates in the development of new technologies for water remediation. More than that, the outcomes of the cytotoxic assays proved that HAp nanoparticles did not induce any noticeable harmful effects against HeLa cells and did not affect their proliferation after 1 day and 7 days of incubation. [ABSTRACT FROM AUTHOR]

The generation of biomaterials via 3D printing is an emerging biotechnology with novel methods that seeks to enhance bone regeneration. Alginate and collagen are two commonly used biomaterials for bone tissue engineering and have demonstrated biocompatibility. Strontium (Sr) and Calcium phosphate (CaP) are vital elements of bone and their incorporation in composite materials has shown promising results for skeletal repair. In this study, we investigated strontium calcium polyphosphate (SCPP) doped 3D printed alginate/collagen hydrogels loaded with MC3T3-E1 osteoblasts. These cell-laden scaffolds were crosslinked with different concentrations of 1% SCPP to evaluate the effect of strontium ions on cell behavior and the biomaterial properties of the scaffolds. Through scanning electron microscopy and Raman spectroscopy, we showed that the scaffolds had a granular surface topography with the banding pattern of alginate around 1100 cm−1 and of collagen around 1430 cm−1. Our results revealed that 2 mg/mL of SCPP induced the greatest scaffold degradation after 7 days and least amount of swelling after 24 h. Exposure of osteoblasts to SCPP induced severe cytotoxic effects after 1 mg/mL. pH analysis demonstrated acidity in the presence of SCPP at a pH between 2 and 4 at 0.1, 0.3, 0.5, and 1 mg/mL, which can be buffered with cell culture medium. However, when the SCPP was added to the scaffolds, the overall pH increased indicating intrinsic activity of the scaffold to buffer the SCPP. Moreover, cell viability was observed for up to 21 days in scaffolds with early mineralization at 0.3, 0.5, and 1 mg/mL of SCPP. Overall, low doses of SCPP proved to be a potential additive in biomaterial approaches for bone tissue engineering; however, the cytotoxic effects due to its pH must be monitored closely. [ABSTRACT FROM AUTHOR]

The hexagonal solid solution La2W1 +xO6 + 3x (x ~ 0.11) and the orthorhombic low-temperature phase β-La2WO6 (La2W1 +xO6 + 3x (x = 0)) are synthesized by the methods of preliminary mechanical activation of oxides followed by high-temperature synthesis at 1400°С, 4 h. In addition, by using the method of crystallization from solution, a single crystal of the La2W1 +xO6 + 3x (x ~ 0.22) composition isostructural to La2W1 +xO6 + 3x (x ~ 0.11) is grown. Both ceramics and the single crystal are studied by the methods of Raman spectroscopy, thermal analysis, and thermogravimetry. Their conductivity is studied by impedance spectroscopy in dry and humid air. The hexagonal single crystal La2W1 +xO6 + 3x (x ~ 0.22) demonstrates strong luminescence in the IR region, in contrast to the hexagonal ceramics La2W1 +xO6 + 3x (x ~ 0.11) and the β-La2WO6 ceramics with the orthorhombic structure. The polycrystalline La2W1 +xO6 + 3x (x ~ 0.11) ceramics is found to be more stable under redox conditions as compared with the single crystal. The conductivity of the hexagonal single crystal La2W1 +xO6 + 3x (x ~ 0.22) is of the oxygen-ionic nature and lower than the conductivity of ceramics La2W1 +xO6 + 3x (x ~ 0.11) due to its perfect structure. The contribution of the protonic component of conductivity is absent for both the hexagonal solid solution La2W1 +xO6 + 3x (x ~ 0.11) and the single crystal La2W1 +xO6 + 3x (x ~ 0.22), their conductivity being of the purely ionic nature with the close values of activation energy (0.89 and 1.08 eV, respectively). The synthesized β-La2WO6 ceramics demonstrates a small contribution of the protonic conductivity in humid air equal to ~1 × 10–6 S/cm at 600°С, which is close to the conductivity of the earlier studied strontium-doped solid solution La1.96Sr0.04WO6 – δ based on β-La2WO6. [ABSTRACT FROM AUTHOR]

The generation, transport, and recrystallization of slab-derived melts/fluids play a critical role in the deep recycling of elements in subduction zones. While boron (B) isotope systematics have been invoked as an important tracer of these processes, its behavior during metamorphic dehydration and partial melting of deeply subducted continental slabs, and the partitioning of B isotopes between minerals and melts/fluids is not fully understood. Here, we investigate these processes through an in situ study of the major, trace-element, and B-Sr isotope variations in different occurrences of tourmaline in migmatite from the Yuka terrane, North Qaidam orogen (China), which resulted from partial melting of a continental slab at different stages during subduction and exhumation. Based on textural and detailed high-resolution X-ray mapping studies, tourmaline was classified into four paragenetic generations (Tur-I, Tur-II, Tur-III, and Tur-IV). Dravitic Tur-I occurs in melanosomes and shows increasing Fe, Ca, and Ti contents from the core to the outer rim. In addition, it has relatively homogeneous Sr isotope values (0.7407–0.7416) and decreasing δ11B values (-3.8 to −8.6 ‰) and X Mg (Mg/(Mg + Fe)) ratios, indicating formation in a rock buffered by an aqueous fluid during the prograde to peak metamorphism. Schorlitic Tur-II occurs within selvage zones between melanosomes and leucosomes, and yields high-Fe values and low δ11B (-13.5 to −10.9 ‰) and more variable 87Sr/86Sr (0.7343–0.7418) values, indicating crystallization in the presence of a hydrous melt external derived from breakdown of Fe-rich mineral(s) during partial melting of the subducted slab. Dravitic Tur-III formed in the matrix and also enveloped Tur-II. It shows homogeneous 87Sr/86Sr values (0.7411–0.7420) and decreasing δ11B values (-6.8 to −9.9 ‰) and X Mg ratios as well as increasing Fe and Ti contents from core to outer rim. Formation of Tur-III reflects a transitional stage from hydrous melt to aqueous fluid during exhumation. Tur-IV in the leucosomes is essentially a schorl-dravite solid solution with small amounts of Ca. Its 87Sr/86Sr values (0.7402–0.7416) and δ11B values (-11.4 to −8.5 ‰) are intermediate between the respective values of Tur-II and Tur-III. The formation of Tur-IV likely results from interaction between melt and fluid and, based on its chronological sequence, and is interpreted to have formed during the exhumation stage of the Yuka terrane. Overall, the variable X Mg ratios and δ11B values in the different generations of tourmalines are a consequence of the evolution of the melt/fluid at different depths within the deeply subducted slab. Decreasing δ11B values from Tur-I to Tur-II and Tur-III are controlled by the breakdown of different minerals during partial melting or metamorphic dehydration of the subducted slab, while the co-variations of the elemental geochemistry and B isotopic compositions of tourmaline reflect different depths of formation during subduction and exhumation of the lithosphere. These observations suggest tourmaline may serve as a useful tracer of multiple melt/fluid–rock interactions and of boron cycling in continental subduction zones. The heterogeneity of δ11B in melts/fluids at different depth levels of the continental subducted slab may also result in locally variable B isotope values in syn- and post-collisional magmas. [ABSTRACT FROM AUTHOR]

Hierarchical organic structures have gained vast attention in the past decade owing to their great potential in chemical and medical applications in industries such as the food and pharmaceutical industries. In this paper, the crystallization of L-glu hierarchical spheres using inorganic ions, namely calcium, barium and strontium cations, is described. The anti-solvent precipitation method is used for the spherical crystallization. The L-glu microspheres are characterized using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photo-electron microscopy (XPS) and polarized microscopy (POM). It is shown that without additives, L-glu crystallizes as flower-like structures, very different from the hierarchical spheres crystallized with the charged additives. Based on our results, we suggest a mechanism for the hierarchical sphere formation based on the crystallization and self-assembly of L-glu in emulsion droplets using charged additives. [ABSTRACT FROM AUTHOR]

Background: Bone graft is a substitute material that is used to assist reconstruction, stabilize the structure and bonds in bone, stimulate the osteogenesis process and as a healing bone defect. One type of bone graft that has good osteoinductive and bicompatibility is alloplast which is a synthetic calcium phosphate compound. The most frequently used Calcium Phosphate groups are Hydroxyapatite (HA), β-Tricalcium Phosphate (β-TCP), and Biphasic Calcium Phosphate (BCP). In this study the material used was BCP doping Sr2+ and Ag+. Strontium ions (Sr2+) can increase osteoblast activity, reduce osteoclast activity and cytokine production, improve osteointegration, and minimize fractures. Ag+ ion has the ability as an antibacterial agent. Purpose: To explain and prove the toxicity of bioceramic Biphasic Calcium Phosphate (BCP) doped Sr-Ag as bone graft on BHK-21 fibroblast cells. Methods: This type of research is a laboratory experiment with a post-test only control group design. Treatment with Biphasic Calcium Phosphate (BCP) doped Sr-Ag with concentrations of 200 ppm, 180 ppm, 160 ppm, 140 ppm, 120 ppm, 80 ppm, 40 ppm, 20 ppm, 10 ppm, 5 pmm, 2.5 ppm, 1.25 ppm, 0.625 ppm in BHK-21 fibroblast cell culture. Results: The percentage of fibroblast cell life at concentrations of 200 ppm, 180 ppm, 160 ppm, 140 ppm, 120 ppm, 80 ppm, 40 ppm, 20 ppm, 10 ppm, 5 pmm, 2.5 ppm, 1.25 ppm, 0.625 ppm, respectively, the percentage of live cells was 38% 44%, 46%, 50%, 52%, 65%, 69%, 71%, 72%, 75%, 77%, 81%, and 87%. The parameter used in this toxicity test is CD50. Conclusion: The results of the toxicity test of bioceramic Biphasic Calcium Phosphate (BCP) doped Sr-Ag as a bone graft showed a toxic and non-toxic effect on BHK-21 fibroblast cells at certain concentrations. [ABSTRACT FROM AUTHOR]

In this study, a zirconium-metal organic framework/graphene oxide (UiO-66-NH 2 /GO) nanofiltration membrane has been prepared with the assistance of branched polyethyleneimine (PEI). This PEI-assisted method facilitates a more uniform dispersion of UiO-66-NH 2 within the GO membrane, thereby enhancing the structural stability of the membrane during membrane separation. The as-prepared membrane has exhibited excellent performance in removing radioactive strontium ions, which is a trending research field in nuclear wastewater treatment. A comprehensive investigation into the separation mechanism of the PEI-UiO-66-NH 2 /GO membrane has revealed a synergistic effect involving size exclusion and electrostatic repulsion. Furthermore, the PEI-UiO-66-NH 2 /GO membrane has consistently achieved high strontium rejection across a wide range of strontium concentrations, pH levels, and even in the presence of other interfering ions. More significantly, the membrane has demonstrated remarkably enhanced capacity for selectively separating binary mixtures of cesium and strontium, offering practical relevance. Our results have indicated that the PEI-UiO-66-NH 2 /GO membrane holds considerable promise for the separation of strontium ions. [Display omitted] • The role of PEI in facilitating the formation of UiO-66-NH 2 /GO membrane is comprehensively studied. • PEI-UIO-66-NH 2 /GO membrane demonstrates enhanced water permeance and strontium rejection ratio compared to GO membrane. • The resulting membrane exhibits robust strontium separation performance across diverse testing conditions. • The resulting membrane shows great potential in selective separation of strontium and cesium. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional composite Ti-Ta@Sr substrates is successfully fabricated. • The rat model of diabetic bone defect was successfully constructed. • The Ti-Ta@Sr which we created possess potential to remove reactive oxygen species and promote bone formation. • The coating is beneficial for bone formation in diabetic rats. The aging population is closely associated with chronic metabolic diseases, including diabetes, hypertension, and other metabolic disorders. Metabolic dysfunction is a primary characteristic of diabetic patients, which can impair cellular response to insulin and lead to increased production of reactive oxygen species (ROS), hindering bone healing. Therefore, the development of multifunctional titanium (Ti) implants with the ability to eliminate reactive oxygen and promote bone formation is the optimal strategy to address this issue. In this study, we designed a thioctic acid(Ta) coating loaded with strontium(Sr), forming a strong bond with the Ti implant (Ti-Ta@Sr). During treatment, sulfuric acid demonstrated the ability to release monomers in the early stages, effectively eliminating excess reactive oxygen produced in high-glucose environments and regulating the diabetic microenvironment. The delayed in-situ release of strontium ions also enhanced osteogenic differentiation efficiency. Both in vivo and in vitro experiments confirmed that Ti-Ta@Sr significantly restored the osteogenic capacity and proliferation of osteoblasts under high-glucose conditions. These advantages make Ti-Ta@Sr a promising candidate material for orthopedic implants, suitable for repairing bone defects in diabetic patients. [ABSTRACT FROM AUTHOR]

[Display omitted] • Herein, we designed a micro/nanoscaled hierarchical topography and simultaneously incorporated strontium ions and zinc ions onto titanium surface (SLA-Sr/Zn). • SLA-Sr/Zn exhibited potent pro-angiogenic capacity, exerted robust osteogenic potential and orchestrated a favorable osteoimmune microenvironment by modulating macrophage polarization towards M2a phenotype. • The underlying molecular mechanism was associated with Akt/HIF-1α signaling pathway. • This work fabricated the distinct SLA-Sr/Zn titanium implant surface with multifunctional capacities, endowing a comprehensive process optimization for rapidly vascularized osseointegration. Osseointegration involves a series of sophisticated physiological processes including osteoimmune responses, angiogenesis, and osteogenesis. However, a comprehensive process optimization to tackle the dilemma of the prolonged implant osseointegration still remains a challenge. In this study, we designed a micro/nanoscaled hierarchical topography and simultaneously incorporated strontium ions and zinc ions onto titanium surface (SLA-Sr/Zn). SLA-Sr/Zn exhibited potent pro-angiogenic capacity in vitro by expressing essential angiogenic genes and activating Akt/HIF-1α signaling pathway of human umbilical vein endothelial cells. Meanwhile, SLA-Sr/Zn exerted robust osteogenic potential by facilitating bone mesenchymal stem cells osteogenic differentiation. Furthermore, the continuous release of dual ions orchestrated a favorable osteoimmune microenvironment by modulating macrophage polarization towards M2a phenotype and up-regulated expression of platelet-derived growth factor. In vivo study corroborated the excellent efficacy of SLA-Sr/Zn implant on promoting vascularized osseointegration by augmenting type H vessel generation. Collectively, the distinct SLA-Sr/Zn titanium implant surface exerted versatile biological functions in angiogenesis, osteogenesis and osteoimmunomodulation, rendering its therapeutic potential for rapidly vascularized osseointegration. [ABSTRACT FROM AUTHOR]

A study was conducted to investigate the sorption of 85Sr from aqueous solutions using a fabricated magnesium molybdenum titanate (MgMoTi) composite. The MgMoTi composites were synthesized through the co-precipitation technique and characterized using different analytical tools, including FT-IR, XRD, SEM, and EDX. The sorption studies focused on 85Sr and examined factors such as shaking time, pH, ionic strength, temperature, initial ion concentration, and saturation capacity. The results obtained from the study indicated that, under optimum sorption conditions, the saturation capacity for 85Sr onto S-4 and S-5 was determined to be 23.31 and 37.72 mg g−1, respectively. The sorption of 85Sr exhibited dependence on pH and ionic strength. The kinetics of the sorption process followed the pseudo-2nd-order model, while the thermodynamics revealed an endothermic and spontaneous nature. Desorption studies revealed that 0.1 M HCl was the most effective eluent for the complete recovery of 85Sr. Furthermore, the recycling results demonstrated the excellent recyclability of MgMoTi, suggesting its potential application as a sorbent for the removal of 85Sr from aqueous solutions. Overall, the study highlights MgMoTi as a promising composite with practical utility in the sorption of 85Sr from aqueous solutions. • MgMoTi composite has been fabricated by the co-precipitation method. • The MgMoTi composite was used for the sorption of 85Sr. • The saturation capacity for 85Sr onto S-4 and S-5 was determined to be 23.31 and 37.72 mg g−1, respectively. • The MgMoTi composite could be reused for repeated sorption-desorption regeneration cycles up to seven cycles with a low reduction in the uptake percentage. [ABSTRACT FROM AUTHOR]

Bone defects, resulting from trauma, inflammation, tumors, and various other factors, affect both health and quality of life. Although autologous bone transplantation is the gold-standard treatment for bone defects, it has disadvantages such as donor site limitations, prolonged surgical durations, and potential complications, necessitating the development of alternative bone tissue engineering materials. In this study, we used 3D printing technology to fabricate porous titanium implants characterized by superior biocompatibility and mechanical properties. Sodium alginate (SA) and strontium ions (Sr2+) were integrated into mineralized collagen matrices (MCs) to develop strontium-functionalized alginate-mineralized collagen hydrogels (SAMs) with high mechanical strength and sustained metal ion release ability. SAMs were seamlessly incorporated into the porous structures of 3D-printed titanium scaffolds, establishing a novel organic–inorganic bioactive interface. This composite system exhibited high biocompatibility in vitro and increased the expression of genes important for osteogenic differentiation and angiogenesis. In a rabbit model of femoral defect, the titanium implants effectively promoted bone and vascular regeneration on their surface, highlighting their potential in facilitating bone–implant integration. • Strontium cross-linked alginate mineralized collagen and titanium form the interface of prosthesis. • Strontium ions and mineralized collagen promote osteogenic differentiation of BMSCs and migration of endothelial cells. • Hydrogel promotes angiogenesis and bone tissue ingrowth around the scaffold in rabbits. [ABSTRACT FROM AUTHOR]

Nanomaterials with unique nanotube arrays have attracted extensive attention in the field of blood-contacting biomaterials. In this study, the regular titanium dioxide nanotube arrays were first prepared on the pure titanium surface by anodic oxidation. Subsequently, copper ions (Cu2+) and strontium ions (Sr2+) were incorporated into the nanotubes by the chelation of dopamine to improve biocompatibility. The as-prepared TiO2 nanotubes had an inner diameter of about 60 nm and an outer diameter of 90–110 nm, as well as a tube length of 4–6 µm. The following annealing treatment and the incorporation of Cu2+ and Sr2+ had little effect on the morphology and dimensions of the nanotubes, but can significantly improve the hydrophilicity, and promote the adsorption of bovine serum albumin concurrently inhibit the adsorption of fibrinogen, showing the effect of selective protein adsorption. At the same time, loading Cu2+ and Sr2+ can also effectively inhibit platelet adhesion and activation, promote endothelial cell growth, and upregulate the expression of vascular endothelial growth factor and nitric oxide. Therefore, the results of this study showed that the incorporation of Cu2+ and Sr2+ into the TiO2 nanotubes can simultaneously improve the hemocompatibility and cytocompatibility of endothelial cells, which can enlarge the application of titanium-based biomaterials in cardiovascular devices such as a stent.

Manganites had been proposed as one of the potential n-type oxide materials to develop thermoelectric power generators. In the present investigation, we studied the structural and thermoelectric properties of Gd1-xSrxMnO3 (GSMO) (0.5 ≤ x ≤ 0.8) polycrystalline ceramics synthesized by a conventional solid-state route. Rietveld refinement of XRD patterns revealed the distorted orthorhombic Pbnm crystal structure in all the compositions. The decrease in J-T distortions, present on the Gd-rich side of GSMO (x ≤ 0.6), due to favored formation of Mn4+ was calculated. Thermoelectric properties such as Seebeck coefficient (S) and electrical conductivity (σ) of these ceramics were measured in the temperature range from room temperature to 900 °C. The negative values of the Seebeck coefficient throughout the temperature range confirm the n-type semiconducting nature in all the compositions. The conduction mechanism (below metal-semiconductor transition) of these materials was analyzed using the small polaron hopping conduction model. [ABSTRACT FROM AUTHOR]

Manganites had been proposed as one of the potential n-type oxide materials to develop thermoelectric power generators. In the present investigation, we studied the structural and thermoelectric properties of Gd1-xSrxMnO3 (GSMO) (0.5 ≤ x ≤ 0.8) polycrystalline ceramics synthesized by a conventional solid-state route. Rietveld refinement of XRD patterns revealed the distorted orthorhombic Pbnm crystal structure in all the compositions. The decrease in J-T distortions, present on the Gd-rich side of GSMO (x ≤ 0.6), due to favored formation of Mn4+ was calculated. Thermoelectric properties such as Seebeck coefficient (S) and electrical conductivity (σ) of these ceramics were measured in the temperature range from room temperature to 900 °C. The negative values of the Seebeck coefficient throughout the temperature range confirm the n-type semiconducting nature in all the compositions. The conduction mechanism (below metal-semiconductor transition) of these materials was analyzed using the small polaron hopping conduction model. [ABSTRACT FROM AUTHOR]

In the paper, we describe a method for searching for the optimal parameters of laser cooling of strontium ions without observing the luminescence signal. The presented method made it possible to obtain a cold cloud of ions, detect the luminescence signal, and achieve the mode of ionic crystals. [ABSTRACT FROM AUTHOR]

High-mobility electron gases in SrTiO3-based heterostructures have been mainly synthesized on single TiO2 terminated SrTiO3 substrates. Here, we show a high-mobility electron gas observed in a Sr2TiO4/SrTiO3 heterostructure based on an untreated SrTiO3 substrate with mixed termination, showing the mobility value up to 28 000 cm2 V−1 s−1 at 2 K. SrO–SrO vertical Ruddlesden–Popper faults in the Sr2TiO4 film provide escape channels for oxygen atoms under high temperatures, enabling the as-grown tuning of oxygen vacancies in the SrTiO3 layer during film deposition and reversible after-growth modulation in a thermal annealing process. [ABSTRACT FROM AUTHOR]

The possibility of using composite sorbents based on natural and synthetic zeolites in relation to a mixture of cations (cesium, strontium and cobalt) was studied as a result of the conducted research. The most effective was the use of a composite sorbent (clinoptilolite—50%: zeolite NaX—50%). This composite sorbent showed high sorption capacity: the sorption of cesium was 80.0%, strontium was 70.3%, cobalt was 78.6%. The technique was developed based on the PIXE (Proton Induced X-ray Emission) method and allowed for a qualitative and quantitative assessment of the content of cations. [ABSTRACT FROM AUTHOR]

Sr isotope ratios of hydrothermal fluids were observed at five sediment-associated sites in the Okinawa Trough to investigate the diversity of subseafloor fluid–rock–sediment interactions. The estimated 87Sr/86Sr ratios of the hydrothermal endmember fluids at the five sites were all higher than those at the sediment-starved sites. The endmember Sr isotopic ratios of hydrothermal fluids were diverse within the Okinawa Trough, ranging from 0.7077 at the Iheya North Knoll site to 0.712 at the Yonaguni Knoll IV site. To our knowledge, 0.712 is the highest value reported to date for seafloor hydrothermal fluids. This variation is likely attributable to the relative contributions of multiple subseafloor Sr reservoirs, which are 87Sr-poor volcanic rock and 87Sr-rich hemipelagic sediments containing clay minerals of terrestrial origin. These data support a model based on the carbon isotope ratio of CH4, which indicates whether volcanic rocks or terrestrial sediments are distributed in the high-temperature reaction zone of the hydrothermal system. Key points: The Sr isotopic ratios of hydrothermal fluids from the Okinawa Trough are exceptionally high. The enrichment of 87Sr at Yonaguni Knoll IV cannot be explained without the influence of terrestrial clay minerals in sediments. High Sr isotopic ratios are a common feature of sediment-associated hydrothermal systems. [ABSTRACT FROM AUTHOR]

The KLa(SO4)2–SrSO4 system has been studied at temperatures above 600°C by X-ray diffraction and thermogravimetric analysis. The results demonstrate that the system contains a broad range (0–70 mol % KLa(SO4)2) of solid solutions based on the orthorhombic phase β-SrSO4 (sp. gr. Pnma). We have determined the unit-cell parameters of the solid solutions. Their unit-cell volume has been shown to increase systematically from 307.67(6) to 313.54(21) Å3 in the composition range studied. The solid solutions result from heterovalent substitution of potassium and lanthanum ions for two strontium ions and decompose above a temperature of 950°C to form the SO3 and La2O3 oxides and potassium and strontium sulfates. [ABSTRACT FROM AUTHOR]

Sulfonic resins are highly efficient cation exchangers widely used for metal removal from aqueous solutions. Herein, a new sulfonation process is designed for the sulfonation of algal/PEI composite (A*PEI, by reaction with 2-propylene-1-sulfonic acid and hydroxylamine-O-sulfonic acid). The new sulfonated functionalized sorbent (SA*PEI) is successfully tested in batch systems for strontium recovery first in synthetic solutions before investigating with multi-component solutions and final validation with seawater samples. The chemical modification of A*PEI triples the sorption capacity for Sr(II) at pH 4 with a removal rate of up to 7% and 58% for A*PEI and SA*PEI, respectively (with SD: 0.67 g L−1). FTIR shows the strong contribution of sulfonate groups for the functionalized sorbent (in addition to amine and carboxylic groups from the support). The sorption is endothermic (increase in sorption with temperature). The sulfonation improves thermal stability and slightly enhances textural properties. This may explain the fast kinetics (which are controlled by the pseudo-first-order rate equation). The sulfonated sorbent shows a remarkable preference for Sr(II) over competitor mono-, di-, and tri-valent metal cations. Sorption properties are weakly influenced by the excess of NaCl; this can explain the outstanding sorption properties in the treatment of seawater samples. In addition, the sulfonated sorbent shows excellent stability at recycling (for at least 5 cycles), with a loss in capacity of around 2.2%. These preliminary results show the remarkable efficiency of the sorbent for Sr(II) removal from complex solutions (this could open perspectives for the treatment of contaminated seawater samples). [ABSTRACT FROM AUTHOR]

The aim of the paper consist in the synthesis of double substituted carbonated hydroxyapatite using Zn2+ and Mg2+ ions in comparison with the previous obtained Sr-Zn-CHAp. Fourier transform infrared spectroscopy, X-ray diffraction, environmental scanning electron microscope (ESEM) coupled with EDS is used to highlight the presence of the metallic ions into the apatite structure. Both inorganic compounds are tested as consolidants for two types of fir wood, young and 30-years old samples. The consolidation efficiency is demonstrated by colorimetric analysis, mechanical tests and the specific methods for water absorption behavior. Stronger specimens, especially of young wood, with no significant color differences, more hygroscopic and with higher hysteresis index result after treatment. In conclusion, carbonated hydroxyapatite double substituted with zinc, magnesium and strontium ions can be used in wood preservation-conservation techniques. [ABSTRACT FROM AUTHOR]

In this study, activated carbons derived from walnut shells (CA-N) and apple wood (CA-M) were used as adsorbents to remove cobalt(II) and strontium(II) ions from aqueous solutions. The novel materials were obtained using nitric acid (CA-Mox) and nitric acid/urea mixture (CA-Mox-u, CA-Nox-u) as oxidizing agents. The physical–chemical characteristics of activated carbons were determined from nitrogen sorption isotherms, SEM-EDX, FTIR, pH metric titrations, the Boehm titration method and elemental analysis. The results of batch experiments indicate that maximum adsorption can be achieved in broad pH ranges: 4–8 for Co(II) and 4–10 for Sr(II). The maximum adsorption capacities of Co(II) and Sr(II) on oxidized activated carbons at pH = 4 are: CA-Mox, 0.085 and 0.076 mmol/g; CA-Mox-u, 0.056 and 0.041 mmol/g; and CA-Nox-u, 0.041 and 0.034 mmol/g, respectively. The mathematical models (pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models, and Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin–Pyzhev isotherm models) were used to explain the adsorption kinetics, to study the adsorption mechanism and predict maximum adsorption capacity of the adsorbents. The adsorption mechanisms of toxic metal ions on activated carbons were proposed.

A composite cement made of strontium containing tricalcium silicate and hydroxyapatite (SrC3S/HAp) was prepared and studied through a two-stage sol–gel method. The elemental components are 75 wt% of strontium-doped tricalcium silicate (SrC3S) and 25 wt% of hydroxyapatite (HAp). According to previous studies, the SrC3S has good mechanical properties and hydraulic conductivity, and the HAp has good biocompatibility. Therefore, the 75SrC3S-25HAp powder with 10 wt% of NaH2PO4 solution was mixed to prepare the slurry material. This slurry was measured for the working time and setting time at 37 °C under saturated vapor pressure. The material properties were evaluated in terms of crystal structures, surface morphologies, and mechanical properties. The in vitro testing was conducted to determine the ion release rate and curing behavior under a simulated body fluid environment. Finally, the L929 murine fibroblast cells were cultured to study the biocompatibility of the material. The results indicated that the operating time was 15.2 min, and the setting time was 43.6 min. After being soaked into simulated body fluid for14 days of the experiment, the compressive strength of 75SrC3S-25HAp remained 22.1 MPa, and the release of calcium and strontium ions was 501.4 ppm and 49.5 ppm, respectively. The cell viabilities were higher than 70% in various concentrations. These results suggest the 75SrC3S-25HAp has excellent potential for bone cement application. [ABSTRACT FROM AUTHOR]

An injectable delivery platform for promoting delayed bone healing has been developed by combining a thermosensitive polyurethane-based hydrogel with strontium-substituted mesoporous bioactive glasses (MBG_Sr) for the long-term and localized co-delivery of pro-osteogenic Sr2+ ions and an osteogenesis-enhancing molecule, N-Acetylcysteine (NAC). The incorporation of MBG_Sr microparticles, with a final concentration of 20 mg/mL, did not alter the overall properties of the thermosensitive hydrogel, in terms of sol-to-gel transition at a physiological-like temperature, gelation time, injectability and stability in aqueous environment at 37 °C. In particular, the hydrogel formulations (15% w/v polymer concentration) showed fast gelation in physiological conditions (1 mL underwent complete sol-to-gel transition within 3–5 min at 37 °C) and injectability in a wide range of temperatures (5–37 °C) through different needles (inner diameter in the range 0.4–1.6 mm). In addition, the MBG_Sr embedded into the hydrogel retained their full biocompatibility, and the released concentration of Sr2+ ions were effective in promoting the overexpression of pro-osteogenic genes from SAOS2 osteoblast-like cells. Finally, when incorporated into the hydrogel, the MBG_Sr loaded with NAC maintained their release properties, showing a sustained ion/drug co-delivery along 7 days, at variance with the MBG particles as such, showing a strong burst release in the first hours of soaking. [ABSTRACT FROM AUTHOR]