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Statement of problem Strontium has been validated for potent bone-seeking and antiosteoporotic properties and elicits a potentially beneficial impact on implant osseointegration in patients with osteoporosis. However, the efficacy of strontium supplementation on improving new bone formation and implant osseointegration in the presence of osteoporotic bone is still unclear. Purpose The purpose of this systematic review was to comprehensively assess the efficacy of strontium supplementation, encompassing oral intake and local delivery of strontium, on implant osseointegration in patients with osteoporosis. Material and methods Searches on electronic databases (MEDLINE or PubMed, Web of Science, EBSCO, Embase, and Clinicaltrials.gov ) and manual searches were conducted to identify relevant preclinical animal trials up to June 2020. The primary outcomes were the percentage of bone-implant contact and bone area; the secondary outcomes were quantitative parameters of biomechanical tests and microcomputed tomography (μCT). Results Fourteen preclinical trials (1 rabbit, 1 sheep, and 12 rat), with a total of 404 ovariectomized animals and 798 implants, were eligible for analysis. The results revealed a significant 17.1% increase in bone-implant contact and 13.5% increase in bone area, favoring strontium supplementation despite considerable heterogeneity. Subgroup analyses of both bone-implant contact and bone area exhibited similar outcomes with low to moderate heterogeneity. Results of biomechanical and μCT tests showed that strontium-enriched implantation tended to optimize the mechanical strength and microarchitecture of newly formed bone despite moderate to generally high heterogeneity. Conclusions Based on the available preclinical evidence, strontium supplementation, including local and systemic delivery, showed promising results for enhancing implant osseointegration in the presence of osteoporosis during 4 to 12 weeks of healing. Future well-designed standardized studies are necessary to validate the efficacy and safety of strontium supplementation and to establish a standard methodology for incorporating Sr into implant surfaces in a clinical setting.

Background: Gentian violet dye released from industries into the environment has caused serious water pollution and is a significant environmental pollutant to human beings owing to the toxicity. It is urgent to decrease environmental pollution by removing gentian violet in the wastewater. Objective: The aim is to synthesize hexahydroxy strontium stannate/tin dioxide nanocomposites by a simple hydrothermal method without surfactants and research the photocatalytic performance for gentian violet degradation. Methods: Hexahydroxy strontium stannate/tin dioxide nanocomposites have been obtained via the hydrothermal method. The structure, size, morphology and photocatalytic performance were characterized by X-ray diffraction, electron microscopy, solid ultraviolet-visible diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. Results: The nanocomposites possess oven-shaped morphology with the size of less than 100 nm and are composed of hexagonal SrSn(OH)6 and tetragonal SnO2 phases. The band gap of the nanocomposites is 3.52 eV. 10 mg hexahydroxy strontium stannate/tin dioxide nanocomposites have the ability to completely degrade 10 mL gentian violet solution with the concentration of 10 mgL-1 under 6 h ultraviolet-visible light irradiation. Hydroxyl radical, hole and superoxide radical are the main species for the gentian violet photocatalytic degradation using the nanocomposites. Conclusion: The hexahydroxy strontium stannate/tin dioxide nanocomposites show good photocatalytic performance for the GV degradation. The photocatalytic performance for gentian violet degradation using the hexahydroxy strontium stannate/tin dioxide nanocomposites depends on the irradiation time and content of the nanocomposites.

Orange II is an azo dye widely used in textile industry. Its discharge into water bodies is harmful to the ecosystem and causes health hazard. The removal of organic pollutants from wastewater by photocatalyzed discoloration processes has been thoroughly studied. Notwithstanding, it would be interesting to support the catalyst on magnetic materials in order to facilitate its recovery. In the present work, catalytic discoloration of Orange II was performed using zinc oxide nanopowder in aqueous suspension and novel composites of zinc oxide supported on magnetic materials. We report aone-step methodfor the synthesis of composites, by precipitation of zinc oxide on hard strontium ferrites, that may improve catalyst remotion from water without decreasing its catalytic performance. Composites were structural and magnetically characterized. The discoloration process, scanned by spectrophotometry for six hours, followed a first order kinetics, with a reaction rate constant of 0.0142 1/min and a half-life of 49 min for strontium ferrite/zinc oxide in neutral media at 25 °C. Orange II significant adsorption on catalysts was discarded. Composites, that showed great stability in aqueous suspension and excellent photocatalytic properties compared with zinc oxide, can be easily removed from water by magnetic decantation, with a significant recovery factor (70%).

The single freshly skinned muscle fibre technique was used to investigate Ca2+- and Sr2+-activation properties of skeletal muscle fibres from elderly women (66–90 years). Muscle biopsies were obtained from the vastus lateralis muscle. Three populations of muscle fibres were identified according to their specific Sr2+-activation properties: slow-twitch (type I), fast-twitch (type II) and hybrid (type I/II) fibres. All three fibre types were sampled from the biopsies of 66 to 72 years old women, but the muscle biopsies of women older than 80 years yielded only slow-twitch (type I) fibres. The proportion of hybrid fibres in the vastus lateralis muscle of women of circa 70 years of age (24%) was several-fold greater than in the same muscle of adults (2+- and Sr2+-activation properties of slow-twitch fibres from the two groups of elderly women, but there were differences compared with muscle fibres from young adults with respect to sensitivity to Ca2+, steepness of the activation curves, and characteristics of the fibre-type dependent phenomenon of spontaneous oscillatory contractions (SPOC) (or force oscillations) occurring at submaximal levels of activation. The maximal Ca2+ activated specific force from all the fibres collected from the seven old women use in the present study was significantly lower by 20% than in the same muscle of adults. Taken together these results show there are qualitative and quantitative changes in the activation properties of the contractile apparatus of muscle fibres from the vastus lateralis muscle of women with advancing age, and that these changes need to be considered when explaining observed changes in women’s mobility with aging.

This research aims to define a chemical, mineralogical and strontium isotope database for clayey materials collected along the Nile River banks (White Nile, Blue Nile, Atbara and Main Nile Rivers) in Sudan, to be use for prehistoric and historic pottery provenance studies. The approach here adopted consists in using the clayey materials tout court, without any pre-treatment, such as the depuration from the sand- and silt-sized fractions, in order to maintain unaltered the mineralogical and geochemical features of the natural resources possibly available also in ancient times for the pottery production, thus avoiding any possible preparation bias. Results indicate that sediments along different sections of the Nile River display characteristic geochemical and strontium isotopic signature, representing an important discrimination tool applied to ancient ceramics provenance and human mobility studies.

The strontium (Sr) concentration and 87Sr/86Sr ratios in leachates extracted from Upper Permian (Wuchiapingian) coals from the Tianjia Mine, Chongqing, southwestern China, were investigated using a selective leaching sequential extraction technique including deionized water, dilute HCl, and a mixture of HF and HNO3. The results show that the Sr concentrations in water-leachates (mean value of 12.9 ppm) and HCl-leachates (78.4 ppm) are lower than HF/HNO3-leachates (131 ppm). The water-leachates had more radiogenic (0.707182–0.707642) 87Sr/86Sr ratios than HCl-leachates (0.707111–0.707609), while the 87Sr/86Sr ratios in the HF/HNO3-leachates had a wide range (0.706972–0.707807), and the highest 87Sr/86Sr ratios. These variations in Sr concentration and 87Sr/86Sr ratios are most likely related to the differential solubility of the different Sr-bearing minerals in the coals, in addition to the Sr associated directly with the organic components of the coals. While the Sr/Ca ratios of the HCl-leachates (median=11.3 mmole/mole) were similar to the ratio of marine carbonate dissolution, the 87Sr/86Sr values in the HCl-leachates were higher than the expected 87Sr/86Sr range of the contemporaneous seawater (0.70700–0.70725) recorded in the Wuchiapingian marine carbonate rocks. This indicates that the carbonate minerals in the coals are not of a syngenetic marine origin, despite the indications that the coal seams were influenced by seawater. The textural properties of the cell and fracture-filling carbonate minerals provide evidence that the carbonate minerals in the Tianjia coals are of late diagenetic or epigenetic origin. The combination of isotopic evolution trends of the coal seam, the petrological characteristics (high vitrinite reflectance and bireflectance) and mineralogical assemblage of NH4-illite-paragonite and kaolinite-paragonite as well as authigenic minerals such as calcite, ferroan dolomite, chamosite, quartz, anatase, and florencite suggests that the Tianjia coals was likely affected by diagenetic processes such as sediment dewatering with increasing burial depth (i.e., upward migration of pore fluids from the mudstones interbedded with the coal seams). These conclusions agree with the regional geological history marked by large-scale uplift and denudation of the crust following regional tectonic evolution (i.e., Dongwu Movement, 258–260.5 Ma).

Ceramic materials were synthesized in the RO(R=Ba, Sr)–Al2O3–SiO2 system using exothermic synthesis from solutions containing barium and strontium nitrates, silica and organic reducing agents (glycine and carbamide). It was shown that only the use of a mixture of glycine and carbamide as well as the addition of ammonium nitrate allows carrying out a complete exothermic synthesis with the formation of an X-ray amorphous product with a small fraction of the crystalline phase. It was established that monophase materials based on barium and strontium aluminosilicates (BaAl2Si2O8 and SrAl2Si2O8) are formed when the obtained X-ray amorphous product is heat-treated at the temperatures above 10000C. Ceramics from synthesized materials sintered at 15500C has a high refractoriness, open porosity of 0–1.0%, compressive strength of 115–120 MPa; dielectric constant of 3.25–6.0 (at the frequency of 1 MHz) and the loss tangent of (1.5–5.2)10–3. The results shows that the exothermic synthesis ensures the preparation of nano- and sub-microcrystalline powders in the system RO(R=Ba, Sr)–Al2O3–SiO2. Materials based on the obtained aluminosilicates can be used in the manufacture of protective structures for devices operating in the radio frequency band, in radar installations of aviation and rocket technology, in microwave elements, etc.

A type of strontium and amorphous calcium phosphate dipped premixed injectable tricalcium silicate-based dental root canal sealer was developed as the following protocols. A powder mixture containing tricalcium silicate, strontium carbonate (6, 8, 10, and 12 wt%), zirconia (20 wt%), calcium chloride (6 wt%), and amorphous calcium phosphate (ACP) (5 wt%) was mixed with liquid polyethylene glycol 400 (PEG 400) at a liquid-to-powder ratio of 0.5 mL/g and mechanically ground using a planetary ball to obtain the premixed injectable calcium silicate-based sealer. The sealer’s physicochemical property and cytocompatibility were evaluated in vitro. Quantitative data were expressed as mean ± standard deviation, and Student's t-test or a one-way analysis of variance (ANOVA) test were carried out at significant differences with P

Based on bioactive glasses (BG) of 58S, sol–gel method is used to prepare strontium oxide substituted bioactive glasses (SrO-BG) with different strontium content. SrO-BG and nano hydroxyapatite (HAp) composite materials were synthesized using precipitation method. The phase composition and morphologies of the prepared materials were examined by x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The dissolution and bio-mineralization of SrO-BG and SrO-BG/HAp composites in SBF are investigated by immersion method. The effects of secretion components of macrophages regulated by strontium doped SrO-BG/HAp composites on the osteogenic differentiation (OD) of bone marrow mesenchymal stem cells (BMSCs) are analyzed. The results demonstrate that the SrO-BG can inhibit the dissolution of BG. Different proportions of SrO-BG/HAp composites show good ability to induce HAp in SBF. The bio-mineralization ability of SrO-BG/HAp composites increases with the increase of SrO-BG content. The results of dissolution behavior and bio-mineralization of SrO-BG/HAp composite show that the dissolution rate of each ion can be controlled by adjusting the content of SrO-BG in the composite, and then the degradation rate can effectively be controlled. The results of in vitro experiments show that SrO-BG/HAp composites with 2%, 5% and 8% strontium content are more effective in promoting M2 polarization of macrophages than SrO-BG/HAp composites with 0% strontium content. Among them, 5% strontium doped SrO-BG/HAp has the strongest effect on M2 polarization of macrophages, and the secretion of macrophages regulated by 5% strontium doped SrO-BG/HAp composite is more conducive to bone repair.

Sodium silicate is always used as an activator for the synthesis of geopolymer. However, the effect of sodium silicate concentration on the geopolymer used as adsorbent was still unclear. Therefore, the immobilization of Sr2+ in geopolymers activated by different concentrations of sodium silicate was studied through kinetic and isotherm modeling and solid characterizations including XRD, FTIR, TG, SEM–EDS, and N2 adsorption–desorption isotherm. The adsorption amount of Sr2+ decreased with the sequence of S1, S2, and S3. According to the kinetic and isotherm modeling results, these sorption processes fitted better with pseudo-second-order, mainly governed by film diffusion. However, the diffusion mode was gradually closed to particle diffusion as for the sequence of S3, S2, and S1. Besides, the Langmuir model can be more befitting to sorption data than the Freundlich model, and the free energies decreased with the order of S1, S2, and S3. In addition, the specific surface areas did not change regularly with S1, S2, and S3. Thus, the distribution of Al tetrahedrons has a decisive role in the sorption process of Sr2+, even though the specific surface area is also a critical factor. More Al tetrahedrons can be formed under the activation of sodium silicate with higher concentration, leading to the low Si/Al molar ratio of the as-synthesized geopolymer.

Phase diagram of the ternary oxide system FeO - SrO -Al2O3 was constructed for the first time. In this system, the following compounds can be formed: hercynite FeAl2O4 and five strontium aluminates - Sr4Al2O7 , Sr3Al2O6 , SrAl2O4 , SrAl4O7 , SrAl12O19 . According to the calculations performed, solid solutions of oxides are not formed in the system, as it is confirmed by the literature data. In the course of modeling, the optimal energy parameters of the theory of subregular ionic solutions were selected for the components of the oxide melt (FeO, SrO, Al2O3 ). Thermodynamic analysis of strontium deoxidizing ability in liquid iron at presence of aluminum was carried out using the technique for constructing the surface of solubility of strontium and aluminum in metal for steelmaking temperatures (1550 and 1600 °C) and carbon concentrations of 0.1 and 0.4 %. The equilibrium constants of the reactions of formation of strontium aluminates Sr3Al2O6 and SrAl2O4 from the components of the metal melt were calculated for the temperature range of 1550 - 1650 °C. It was found that the rest of strontium aluminates can be formed in liquid metal only at temperatures above 1750 °C. The base of thermodynamic data for the studied systems is given: temperature dependences of equilibrium constants for reactions occurring between components; values of interaction parameters of the first order (according to Wagner) for elements in liquid iron; values of energy parameters of the theory of subregular ionic solutions (for oxide melt). It follows from the calculations that the formation of strontium monoaluminate SrAl2O4 and corundum Al2O3 is most probable as the interaction products in Fe -Al - Sr - O and Fe -Al - Sr - C - O systems.

Road dust which is a contamination indicator in the environment may contain high levels of heavy metals, which can continue for a long time in the urban areas causing various problems to living organisms. Heavy metals in urban road dust can originate from many moving and steady sources such as industrial discharges, vehicle releases, atmospheric deposition, and natural geochemical processes in urban areas. In this study, assessment of contamination trace metals is investigated including antimony (Sb), barium (Ba), bismuth (Bi), gallium (Ga), lanthanum (La), scandium (Sc), strontium (Sr), and tungsten (wolfram, W) in Istanbul road dust by using enrichment factor (EF), pollution load index (PLI), contamination factor (CF), and contamination degree (Cd). In addition, statistical methods like correlation and multivariate analysis are used to identify the causative resources of these metals. According to the results of this study, PLI values are higher than 1 for all trace metals. The EF values are also found to be high for Sb, Bi, and W. The CF indicators of trace metals show moderate contamination for Ba, Sr, and Bi, and considerable contamination for W, and a very high contamination factor for Sb. The current findings indicate that anthropogenic activities are the main trace metals’ resource in Istanbul road dust samples.

LiMn2 O4 (LMO) cathodes suffer from limited cycle life, resulting from Mn dissolution and side reactions between electrode and electrolyte. In this study, Sr-modified LMO is prepared by using a simple strategy. The nature and position of large-radius Sr ions are investigated, alongside their influence on the structural stability of the bulk. SrMnO3 (SMO) is found to be enriched at grain boundaries of LMO, with Mn-O-Sr bonds forming at the SMO/LMO interface. Furthermore, stable SMO alleviates the migration of Mn ions in LMO associated with structural integrity and suppresses side reactions between the electrode and electrolyte. The modified LMO cathodes maintain their structural integrity and display improved rate performance and cycling stability under harsh conditions. Remarkably, the discharge capacity of a Sr-modified LMO||Li half-cell maintains 94.8 % at 25 °C and 79.6 % at 55 °C after 500 cycles. Consequently, enrichment of strontium at grain boundaries presents a promising strategy for developing cathodes for long-term use.

In this research, the study of two dopants, strontium oxide and manganese oxide were thoroughly investigated based on the elastic properties for the purpose of high strength glass application. The melt quenching technique method was used to synthesize two series of borotellurite glass systems doped with manganese and strontium. Elastic measurement, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the prepared glass samples. The increment of molar volume confirmed the theory that molar volume is inversely proportional to the density parameters. A broad hump was observed during XRD as the samples shows pure amorphous nature. In FTIR, the vibrations of the functional group of the tellurite network were recorded such as TeO4 trigonal bipyramids and TeO3 trigonal pyramids, by addition of both dopants. On the other hand, ultrasonic velocity was used to determine the elastic moduli of the glass such as bulk modulus, shear modulus, longitudinal modulus, Young’s Modulus, microhardness and Poisson’s ratio which showed decreasing and increasing trends with the increased concentration of MnO2 and SrO respectively. It is also inferred that strontium oxide has better elastic properties than manganese oxide.

In the present investigation, we fabricated strontium (Sr2+) incorporated CsPbI2Br-based inorganic perovskite solar cells in ambient conditions. The morphology, crystallinity, absorption, elemental composition and photoluminescence analysis of the bare CsPbI2Br and CsPb1-xSrxI2Br perovskite thin films were studied systematically to investigate the role of Sr2+ incorporation. It is observed that the surface morphology of the CsPbI2Br perovskite thin film has been improved by partial substitution of Pb2+ by Sr2+ which facilitates photoactive black phase-stabilization and defect passivation. The champion device having CsPb0.98Sr0.02I2Br composition exhibited a power conversion efficiency (PCE) of 16.61% which is much higher than the bare device (13.65%). Furthermore, our CsPb0.98Sr0.02I2Br-based devices maintain > 85% of its initial efficiency over 100 h in ambient conditions.

In this work, Nb-substituted barium strontium cobaltites Ba0.5Sr0.5Co1-xNbxO3-δ (x = 0 – 0.4) have been fabricated and studied. The structural analysis showed that the Nb content influences the lattice constant as well as the distance between the (Co, Nb) and oxygen atoms. The study of morphology of samples showed that the Nb content does not change the porosity, grain size and morphology of the ceramics. The total electrical conductivity was studied as a function of temperature and pO2/pH2O. It was shown, that total conductivity is influenced by the cobalt to niobium ratio while the conduction mechanism was similar in all analyzed samples. Transport properties and the presence of protonic conductivity were studied in a dry and humidified atmosphere. A non-negligible difference between total conductivities in dry and wet atmospheres below 500 °C was observed what indicates the presence of protonic defects in these structures. Hydrogenation as a predominant protons formation mechanism was proposed.

This study investigated the influence of Sr2+ ions incorporation in calcium phosphates formation on the surface of Al2O3/ZrO2 (5 vol%) nanocomposites. For this, Al2O3/ZrO2 samples were shaped, calcined (400 °C for 1 h), and sintered (1500 °C for 2 h). After surface treatment with aqueous phosphoric acid solution (H3PO4), the nanocomposite was biomimetically coated with Simulated Body Fluid (SBF) solutions 5x enriched with different concentrations of Sr2+ ions for 14 days. The samples were then characterized by confocal microscopy, scanning electron microscopy (SEM), contact angle and X-ray diffraction. In general, the formation of phases attributed to both calcium phosphates and strontium on the surfaces of nanocomposites was observed, evidencing the partial replacement of calcium ion (Ca2+) by strontium ion (Sr2+) in the structure of phosphates. Thus, the following phases were identified: tricalcium α-phosphate (α-TCP), tricalcium β-phosphate (β-TCP), tetracalcium phosphate (TTCP), hydroxyapatite (HAp), strontium phosphate (SrP) and Sr-incorporated HAp (Sr-HAp). Moreover, Sr2+ ions incorporation in the structure of phosphates also influenced their morphology. Therefore, Sr2+ ions increase adsorption, bioactivity and osteoconduction of calcium phosphates.

The influence of calcium fluoride, zinc oxide, and boron oxide as modifying additives on the melting and crystallization properties of strontium aluminosilicate glasses is examined. The influence of the type and amount of the modifying additive on the homogeneity of the molten glass and the quality of glass castings was evaluated visually. Bulk crystallization and XRD were used to study the effect of additives on the formation of the crystalline structure of the glasses.

Introduction. Excessive intake of heavy metals of natural origin with drinking water increases the risk of the formation of non-infectious diseases of systems and organs, depending on the tropism of the chemical compound. The aim is to study the incidence of disorders of bone density and structure (osteopathies) in children and adolescents who consume drinking water with an increased strontium content due to the geochemical characteristics of the territory. Materials and methods. The observation group consisted of 93 children living in a geochemical province with a stable strontium content of more than 2 MPC in the centralized drinking water supply system. The comparison group included 148 children living in an area where strontium concentration in drinking water does not exceed 1 MPC. The incidence evaluation was carried out according to the official data of statistical materials. The analysis of the average values of the concentration in the blood of strontium, ionized calcium, inorganic phosphorus and alkaline phosphatase activity and the frequency of deviations from the norm of the studied parameters was carried out in the studied groups. The value of bone mineral density (Z-index) was determined according to the results of ultrasonic densitometry. Results. The level of long-term incidence of osteopathies for the period 2010-2019 in children and adolescents, the observation area was 6.59 ± 1.32 and 11.26 ± 2.07 ‰, respectively, which was 1.8 and 2.0 times higher than the level of the comparison territory (p = 0.0003-0.0004 ). The concentration of strontium in the blood of children living in the territory of the geochemical province exceeded 2.1 times the permissible reference (p

This work studies the adsorption of zirconium ions by mesoporous titanium dioxide with surface arsenate groups. Experimental maximal adsorption values of zirconium ions were found to be 109.6 mg/g in neutral medium. This process depends on the interaction time, the equilibrium concentration of zirconium ions, and the acidity of the solution. Adsorption kinetics fit well into the kinetic model based on the pseudo-second-order equation (R 2 = 0.9984). Equilibrium adsorption of zirconium ions is well described by Langmuir’s adsorption theory (R 2 = 0.9856 and χ 2 = 1.307). Although zirconium ions are less actively adsorbed from a neutral medium than strontium or yttrium ions, in the 2% nitric acid only zirconium is adsorbed out of the mixture of zirconium, strontium, and yttrium. The results obtained by inductively coupled plasma mass spectrometry have shown that the investigated adsorbent selectively adsorbs zirconium ions from their mixture with strontium and yttrium in the range of solution acidity pH = 0–1. The average percentage of maximum extraction of zirconium ions is 94.3 ± 2.4%, and the highest percent of zirconium ions taken up from the mixture with strontium and yttrium is ∼98.4%. Investigated titanium dioxide selectively separate 90Zr from 90Sr with the presence of 1000-fold excess of stable 88Sr in radioactive liquid β − source. This fact is extremely valuable for the age dating of 90Sr-containing device in nuclear forensics or the determination of 90Sr in low activity background samples.

137Cs+ and 90Sr2+ are highly soluble, highly environmentally mobile, and strongly radiotoxic. Efficiently sequestering 137Cs+ and 90Sr2+ ions from aqueous solutions remains a serious challenge, esp...

The frequency and full width at half maximum (FWHM) data of the Ag Raman modes (95.4, 231.4 and 263.2 cm−1) in strontium stannate crystal have been analyzed using the Balkanski model and the fittin...

This paper investigates the physical and chemical regularities (isotherm and kinetics) of the sorption of strontium and cesium ions from the seawater. Cesium ions were extracted by sorbents based on transition metal ferrocyanides (Anfezh, Niket, Uniket, FSS, FD-M, Termoxid 35, NKF-C), resorcinol–formaldehyde polymer (Axionit RCs), zirconium phosphate (Termoxid 3A), strontium ions—by sorbents based on manganese oxide (Modix, MDM, DMM, fiber impregnated with MnO2), phosphorus oxide (FD), zirconium hydroxide (Termoxid 3 K), barium silicate (SRM-Sr). The obtained dependences of the sorption parameters on time were described using the models of intraparticle diffusion, pseudo-first, pseudo-second-order, and Elvoich; the dependences of the sorption parameters on the equilibrium concentration of the metal in the solution were described using the Langmuir, Freundlich, and Dubinin-Radushkevich sorption isotherms.

Introduction: The conditions of haptic contamination with stable strontium disrupt the implementation of programmed cell death, forming early health disorders of the child population. Aim: to study the indicators, characterizing cell death, in children with excess haptic contamination of biological media with natural stable strontium. Methods: Research group: children consuming drinking water from underground drinking water sources with excess content of natural stable strontium, comparison group: children consuming drinking water of satisfactory quality in terms of strontium content.The study of indicators characterizing cell death was carried out by flow cytometry; polymorphism of candidate genes by real-time PCR. Results: It was found that in children exposed to strontium, the content of protein-oncosuppressor p53, proapoptotic reception of CD95+- lymphocytes, Annexin V-FITC+PI--lymphocytes with a simultaneous increase in an average of 1.7 times lymphocytic phenotypes of CD95+- lymphocytes and associated with necrotic death of Annexin V-FITC+PI+-lymphocytes are statistically significant (p < 0.001) decreased by an average of 2.5 times. An increased frequency of the heterozygous genotype of the matrix metalloproteinase gene MMP9 Gln279Arg is 2.5 times higher than the results obtained in unexposed children. Conclusion: The results of the studies allowed us to establish that strontium concentrations in the blood in the range from 0.040 to 0.091 mg/dm3 are associated with inhibition of apoptosis and switching to an alternative pathway of cell death-necrosis, which, against the background of polymorphism of candidate genes, creates a risk of autoimmune pathology.

The chemical characteristic of flowback fluid from hydraulic fracturing for shale gas exploration/production in various localizations is presented. The results of statistical analysis have shown that variability in the chemical composition of these fluids is statistically significant and depends on the time difference between fracturing process and flowback sampling as well as sampling spot within the installation for flowback collection. Parameters which depend on sampling schedule (time and spot of sampling) are as follows: electrical conductivity and concentration of ammonia, boron, barium, calcium, lithium, sodium, magnesium, manganese, sodium, strontium, silicate, bromide, and chloride. Independent parameters are pH, total organic carbon (TOC), concentration of potassium, and iron. The ranges of the values of the characteristic parameters were determined, taking into account the representativeness of the samples, supported by statistical tests. The methods for the reuse of flowback fluids in terms of chemical composition are presented.

Neodymium and zirconium modified strontium bismuth titanate ceramics with content changing from 2.5 to 10 at% Nd and a 2.5 at% Zr of SrBi4Ti4O15 (SrNdxBi4-xZryTi4-yO15, (x = 0.00, 0.025, 0.05, 0.07...

Perovskite oxides with cobalt and strontium element exhibit severe degradation during the operation for the solid oxide fuel cells (SOFC). Here, we report stable non-cobalt and non-strontium La1-xNi0.6Fe0.4O3 perovskite cathodes with improved oxygen reduction reaction (ORR) activity. A-site deficient La1-xNi0.6Fe0.4O3 cathodes within 8 at.% all exhibit the invariable phase structure with LaNi0.6Fe0.4O3 (LNF), and the matched thermal expansion coefficient with that of the (Ce0.90Gd0.10)O1.95 (GDC) electrolyte. The polarization resistance of the La0.94Ni0.6Fe0.4O3 (LNF94) cathode is 0.61 Ω cm2 at 750 °C in air, which is 1/5 of the LaNi0.6Fe0.4O3 (2.78 Ω cm2). The peak power density of the corresponding single cell with LNF94 cathode is 0.37 W cm−2 at 750 °C, which is 2.36 times higher than that of the single cell with LNF cathode (0.11 W cm−2). We further study the long-term stability of LNF and LNF94 cathodes, the polarization resistance of the LNF94 electrode slightly fluctuates around 0.18 Ω cm2 during 50 h operation at 800 °C, while the polarization resistance of the LNF increases by about 15%. This work highlights the A-site deficient LNF as an effective and stable non-cobalt and non-strontium cathode for the intermediate temperature solid oxide fuel cells.

At Earth's surface the stable isotope ratio of strontium (88Sr/86Sr) is predominantly set by biological uptake of Sr and its storage in plant litter. This conclusion was reached from a stable isotope mass balance that was independently validated by direct determination of elemental fluxes between the Critical Zone compartments (rock, soil, vegetation, and stream water) of three field sites located in the Swiss Alps, the US Sierra Nevada, and the tropical highlands of Sri Lanka. These sites cover a gradient in erosion rates, which is inversely related to the residence time of solids in the Critical Zone thereby constituting an “erodosequence”. For eroding landscapes, previous stable isotope models predicted that isotope ratios are set by the rate at which secondary solids form during the conversion of rock to regolith. Counter to this expectation we found that, after release from primary minerals, Sr is partitioned into one fraction taken up by plants and the remainder into dissolved Sr flux. The formation of secondary weathering products such as clays and oxides plays a subordinate role in determining the Sr budget. A Sr isotope fractionation factor for biological uptake was determined for each of the three ecosystems from the average Sr stable isotope composition in bulk plants and its dissolved counterpart in stream water. This fractionation factors range from ca. −0.3 ‰ for the Alps and Sierra Nevada to ∼0 ‰ for the tropical Sri Lanka site. That these isotope fingerprints caused by biologic uptake are preserved means that more Sr was physically removed in plant litter than recycled. Such Sr removal in plant litter appears to be strongest at the slowly-eroding site, whereas the dissolved Sr export by streams is highest at the site with the fastest erosion rate. There, all Sr taken up by plants is returned from litter back into solution. The site with short residence time of solids is the only one at which parent material and dissolved export differ in their Sr isotope composition. Our study shows that the behavior of Sr in the Critical Zone is in stark contrast to that of metals of which the isotope fractionation is not affected by biological uptake (for example lithium, mostly set by formation of secondary solids) or affected by both secondary solid formation and biological uptake (for example silicon). Strontium stable isotope signatures offer the new opportunity to quantify nutrient cycling in the Critical Zone as a function of environmental and ecological parameters.

Aiming at selective adsorption and separation of Y(III) from the Y(III)-Sr(II) group in acid solution, a silica-based TODGA impregnated adsorbent [(TODGA+1-dodecanol)/SiO2-P-F600] has been prepared. Batch adsorption experiments were conducted under the effect of contact time, acid concentration, solution temperature, and adsorption capacity etc. Chromatography recovery of more than 90% Y(III) was successfully achieved under elution with 0.01 M DTPA solution in nitric acid adsorption system, and 0.1 M HCl solution in hydrochloride adsorption system, respectively.

A large-bore Sr vapor laser excited in a nanosecond pulsed longitudinal discharge is reported. The optimal discharge conditions for achieving a maximal average output power at several Sr atom and ion lines in the mid-IR spectral range are determined. High average output power of 29 W (at 25 kHz pulse repetition frequency) and laser pulse energy of 2.9 mJ (at 5 kHz pulse repetition frequency) are obtained at the multiline operation. These values are more than two times better than the ones achieved so far with a single-tube strontium or strontium halide vapor lasers.

Buffer/backfill materials for radioactive waste disposal sites consist of pure bentonite or bentonite-rock mixtures. In this study, the batch test method was used to obtain the sorption characteristics of important radionuclides such as Cs, Sr and Co on buffer/backfill materials; i. e., mixing Wyoming MX-80 bentonite or local Taiwanese Zhi-Shin bentonite with possible host rock (argillite and granite) in different proportions (0∼100%). The distribution coefficients (Kd) for Cs, Sr and Co were obtained from the experiments. The distribution coefficient for the bentonite-rock mixtures were found, with more than 50% of mixing proportion of bentonite to argillite or granite, to have very similar values to that of pure bentonite. Furthermore, it was clearly found that the sorption of Cs, Sr and Co to bentonite-rock mixtures is decreased as ionic strength of the liquid phase is increased from 0.001M to 1M for NaCl solutions. According to the experimental results, in synthetic groundwater, it is quite convenient and helpful to assess the distribution coefficients (Kd) of Cs, Sr and Co for buffer/backfill materials using batch sorption experiments with bentonite-rock mixtures of fixed mixing proportions.

Primary type polyhedral silicon crystals were observed in the vicinity of oxides located at or near the surface of strontium modified semi-solid Al–7Si–Mg castings. The coarse silicon polyhedrons were observed mainly on the outer side of oxides surrounding the macrosegregation regions. The silicon crystals most likely nucleated on AlP-particles located near the oxides. These AlP particles may nucleate on the wetted surface of oxides, or form at different locations in the interdendritic regions.

In the present study, the 238U and 232Th radioactivity afford a perfect indication of the attendance of heavy minerals. Herein, integrated ground gamma-ray spectrometric data, X-ray fluorescence analysis and HPGe gamma-ray spectrometer data are employed to evaluate the natural radioactivity of the studied granite rocks. From X-ray analysis, 13 trace elements were estimated. All samples contain a high concentration of barium, zirconium and strontium. The concentration of uranium is high in all the collected twenty-four granite samples. The radiological hazard indices are computed to evaluate the possibility of applying the granites in various building materials. It was found that the granite rocks of the Southeastern Desert, Egypt are not safe for use as a building material.

The present study was undertaken to investigate the effect of a number of metallurgical parameters on the tensile properties and quality indices of Al-9%Si cast alloys, i.e., 354 and 359, containing 1.8%Cu-0.5%Mg and 0.5%Mg, respectively. The variables investigated were the strontium content, solidification rate and heat treatment conditions. Quality charts were used as a tool to recommend the optimum conditions to be applied to the 354 and 359-type castings. An increase in the solution heat treatment time enhances the tensile properties and the quality index values of the 354 and the 359 alloys. Twelve h was the time judged most suitable for optimum solution heat treatment of these alloys. The solution heat treatment time required to attain specific tensile properties in the unmodified 354 and 359 alloys may be shortened by modifying these alloys with strontium. The effects of Sr-addition on the response of the 354 and 359 alloys to solutionizing treatment diminish upon increasing the solution heat treatment time as, after a certain length of time, both modified and unmodified alloys display almost the same properties for the subsequent solutionizing time. A rapid solidification rate enhances the tensile properties of both 354- and the 359-type casting alloys due to the refinement of the SDAS; modification of eutectic silicon particles; and reduced size and levels of porosity.

The polycrystalline strontium ferrate titanate (SrFe0.1Ti0.9O3, SFTO) thin films have been successfully prepared by chemical solution method. By analyzing the current-voltage (I–V) characteristics, we discuss the conduction mechanism of SFTO. It is found that the number of oxygen vacancy defects is increased by Fe ion doping, making SFTO be with better resistive switching property. Fe ion doping can also enhance the absorption of strontium titanate to be exposed to visible light, which is associated with the change of energy band. The band gap width (2.84 eV) of SFTO films is figured out, which is less than that of pure strontium titanate. Due to more oxygen vacancy defects caused by Fe ion doping, the band gap width of strontium titanate was reduced slightly. The defect types of SFTO thin films can be determined by electron paramagnetic resonance spectroscopy. In addition, we analyzed the energy band and state density of SFTO by first-principles calculation based on density functional theory, and found that Fe ion doping can reduce the band gap width of strontium titanate with micro-regulation on the band structure. A chemical state of SFTO was analyzed by X-ray photo electron spectroscopy. At the same time, the structure and morphology of SFTO were characterized by X-ray diffraction and scanning electron microscope. This study deepens further understanding of the influence of Fe ion doping on the structure and properties of strontium ferrate titanate, which is expected to be a functional thin film material for memristor devices.

By differential thermal analysis, a concentration field suitable for the growth of Zr, Mg co-doped strontium hexagallate crystals was observed that corresponds well with known experimental results. It was shown that the melting point of doped crystal is ca. 60 K higher than that of undoped crystals. This higher melting points indicate hexagallate phase stabilization by Zr, Mg co-doping and increase the growth window of (Mg,Zr):SrGa12O19, compared to undoped SrGa12O19 that grows from SrO–Ga2O3 melts.

Dentin hypersensitivity (DH) is characterized by pain caused by an external stimulus on exposed dentin. Different therapeutic approaches have been proposed to mitigate this problem; however, none of them provide permanent pain relief. In this study, we synthesized and characterized experimental bioactive glasses containing 3.07 mol% SrO or 3.36 mol% K2 O (both equivalent to 5 wt% in the glass), and evaluated their effect on dentin permeability to verify their potential to treat DH. The experimental materials were characterized by field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, micro-Raman spectroscopy, and X-ray diffraction to confirm the respective structures and chemical compositions. The reduction in the hydraulic conductance of dentin was evaluated at the three stages: minimum permeability; maximum permeability (24% ethylenediaminetetraacetic acid [EDTA] treatment); and final dentin permeability after treatment with the bioactive glasses. They all promoted a reduction in dentin permeability, with a significant difference for each sample and posttreatment group. Also, a significant reduction in dentin permeability was observed even after a simulated toothbrushing test, demonstrating effective action of these materials against DH. Besides, incorporating 3.07 mol% SrO was a positive factor. Therefore, strontium's desensitizing and re-mineralizing properties can be further exploited in bioactive glasses to promote a synergistic effect to treat DH.

Heavy metal pollution has a harmful impact on human health and is regarded as a vital problem. Preparation of a novel, low cost bio-sorbent for heavy metal sorption is the main target of this research. Non-living Chlorella Vulgaris Alga/Date pit activated carbon composite (1:1), (CV/AC), is a novel bio-sorbent prepared by the wet-chemical method for sorption of Pb (II) and Sr (II) from aqueous media. The optimum pH for sorption reaction is 5 and the equilibrium time is achieved within 1 h. The sorption efficiencies are 90.5% for Pb(II) and 95.7% for Sr(II) with initial concentration Co 10 mg L–1 at 298 K. The monolayer sorption capacities of CV/AC composite at 298 K and pH = 5 were 6.34 ± 0.059, 5.97 ± 0.22 mg g–1. The saturation capacities were 98.5 and 125 mg g–1 for Pb (II) and Sr (II), respectively after 10 days. The sorption process is a spontaneous and endothermic reaction. It follows a pseudo-2nd-order mechanism. The results are suggestive of the need to adopt CV/AC composite as a potential bio-sorbent of Pb (II) and Sr (II) for waste water treatment.

The purpose is geoecological assessment of the current chemical composition of the snow cover and ice of Listvyanka village, as well as the coastal part of the Baikal Lake area. Materials and methods: The studies were carried out on the basis of chemical analysis of meltwater samples of snow and ice. To assess the current composition of snow and ice in the study area, electrometric methods, titrometry, argenometry, turbidimetry and photometry were used. The content of mobile forms of metals was carried out on the Optima 2000DV instrument – an optical emission spectrometer. The concentrations of suspended solids, sulfates, chlorides, nitrogen-containing substances, phosphates, as well as metals such as chromium, manganese, nickel, copper, zinc, strontium and lead were determined in the studied samples. Results and discussion: Based on the results obtained during the chemical analysis, a modern geoecological assessment of the state of snow cover and ice in the territory under consideration was given. The excess of the MPC for some substances, as well as the territorial patterns of the distribution of pollutants, were revealed. Based on the obtained data, maps of the distribution of suspended substances, sulfates and chlorides were constructed.

The excessive accumulation of reactive oxygen species (ROS) under osteoporosis precipitates a microenvironment with high levels of oxidative stress (OS). This could significantly interfere with the bioactivity of conventional titanium implants, impeding their early osseointegration with bone. We have prepared a series of strontium (Sr)-doped titanium implants via micro-arc oxidation (MAO) to verify their efficacy and differences in osteoinduction capabilities under normal and osteoporotic (high OS levels) conditions. Apart from the chemical composition, all groups exhibited similar physicochemical properties (morphology, roughness, crystal structure, and wettability). Among the groups, the low Sr group (Sr25%) was more conducive to osteogenesis under normal conditions. In contrast, by increasing the catalase (CAT)/superoxide dismutase (SOD) activity and decreasing ROS levels, the high Sr-doped samples (Sr75% and Sr100%) were superior to Sr25% in inducing osteogenic differentiation of MC3T3-E1 cells and the M2 phenotype polarization of RAW264.7 cells, thus enhancing early osseointegration. Furthermore, the results of both in vitro cell co-culture and in vivo studies also showed that the high Sr-doped samples (especially Sr100%) had positive effects on osteoimmunomodulation under the OS microenvironment. Ultimately, the collated findings indicated that the high proportion Sr-doped MAO coatings were more favorable for osteoporosis patients in implant restorations., Graphical abstract Schematic diagram of high Sr-incorporated samples promoting early osseointegration under OS conditions: firstly, the released Sr2+ enhances the activity of CAT and SOD to eliminate excessive endogenous ROS of osteoblasts, endowing superior osteoinduction and anti-oxidative properties; secondly, Sr2+ regulates the cell morphology and the CAT/SOD activity of macrophages by inhibiting their OS and inflammation levels, and thus promotes the polarization of macrophages from M0 to M2; lastly, the overexpression of osteogenic-related cytokines, such as TGFβ1, BMP2 by M2 macrophages effectively ameliorate osteogenesis.Image 1, Highlights • First study on osteogenic difference of Sr-doped implants in normal and OS conditions. • Low Sr-doped MAO coating displays optimal bioactivity in normal microenvironment. • High Sr coating significantly enhances osteoimmunomodulation/osteoinduction under OS. • High Sr sample resists OS damage by activating CAT/SOD and scavenging excess ROS. • High Sr implant restorations are more favorable for osteoporosis patients.