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Ferroelectric strontium barium niobate (SrxBa1−xNb2O6 or SBN) is a material with high electro-optic (EO) response. It is currently of interest in low voltage silicon-integrated photonics (SiPh). We have grown strongly textured SBN films with x = 0.65 by radio frequency sputtering on (100)-oriented SrTiO3 substrates where grains with mixed (310) and (001) out-of-plane orientation form. For these mixed orientation films, we observed a maximum effective EO coefficient of 230 pm/V using a transmission EO measurement geometry that is responsive only to the in-plane polarization component coming from the (310)-oriented grains. We also demonstrate that by growing SBN on TiO2-terminated SrTiO3 substrates, we can obtain predominantly (001)-oriented SBN films with out-of-plane polarization. Transmission EO measurements on such (001)-oriented films show a reduced effective Pockels coefficient of 88 pm/V, which is consistent with the overall ferroelectric polarization becoming out-of-plane. This work shows that controlling substrate termination is effective in controlling the grain orientation of SBN films grown on top and that one can readily integrate SBN films on SrTiO3-buffered Si for use in SiPh. [ABSTRACT FROM AUTHOR]

In this article, a comprehensive study of the effect of calcium substitution on structural magnetic, magnetocaloric properties, and role of Griffiths phase on magnetocaloric properties of half-doped manganites L a 0.5 S r 0.5 − x C a x Mn O 3 (x = 0 , 0.25 , 0.5) ] have been presented. A structural phase transition I4/mcm − Pbnm is observed in the whole series. The system exhibits two magnetic transitions for Ca-00 and Ca-25, whereas only one phase transition is observed for Ca-50. Paramagnetic (PM)–ferromagnetic (FM) transition is observed in the whole series and ferromagnetic (FM) - antiferromagnetic (AFM) phase transition is only observed in Ca-25. Interestingly, short range FM clusters exist in the PM matrix of Ca-50, which is a signature of Griffiths phase (GP). The confirmation of GP has been carried out by performing iso-field magnetization measurements at 200 Oe, 500 Oe, and 1 kOe, respectively. Further magnetocaloric properties have been discussed on the basis of isothermal magnetization curves recorded at certain temperature intervals. Calcium substitution favors the enhancement of magnetic entropy change in the series, especially for Ca-50, a magnetic entropy change of 4.5 J/(kg K) with relative cooling power of 180 J/kg under 5 T magnetic field was observed. Iso-field magnetization and magnetocaloric effect along with critical behavior analysis have been carried out to probe the GP and other inhomogeneities present in the respective series. [ABSTRACT FROM AUTHOR]

Sr 1- x Ce x Fe 12 O 19 and Sr 1- x Ce x Fe 12- y O 19-δ (x = 0–0.2, y = 0–2) powders were synthesized by sol-gel auto-combustion method, and the effect on the structure and magnetic properties of changes in doping concentration and iron content has been investigated. XRD results confirmed the formation of M phase and impurities of CeO 2 and Fe 2 O 3. The SEM results show that cerium doping leads to a decrease in grain size. For Sr 1- x Ce x Fe 12 O 19 , the saturation magnetization increases to 77.73 emu/g first and then decreases with the increase of cerium doping. More importantly, our study also found that as the Ce doping concentration and iron content change, the interaction between the two changes differently. This interaction will have different effects on the occupancy of iron ions at spin-up and spin-down sites, ultimately leading to a significant characteristic change in magnetic properties. For Sr 1- x Ce x Fe 12- y O 19-δ , with the iron content decreases, the magnetic properties continue to decrease at x = 0.03, increase first and then decrease at x = 0.1, and keep improving at x = 0.2. It is of reference significance to change the magnetic properties of strontium ferrites by adjusting the relationship between rare earth doping concentration and iron content. [ABSTRACT FROM AUTHOR]

This research was focused on the influence of manganese (Mn) incorporation at Sr and/or Ti sites on the microstructure, relative dielectric permittivity and specific magnetization of strontium titanate (SrTiO 3) ceramics. A solid-state method was used for the preparation of mechanically activated (10, 30 and 120 min) Mn-doped SrTiO 3 ceramics with various manganese dioxide (MnO 2) weight percentages (1.5, 3 and 6 wt%). Rietveld's analysis showed that the mean crystallite size in doped-activated SrTiO 3 ceramics is smaller than in undoped ceramics, which is a consequence of additional crystal structure distortion due to ion substitution. Changes in the Raman spectra indicated dopant incorporation in the SrTiO 3 lattice. The microstructural analysis pointed out a decrease in the mean grain size with increasing dopant concentration and time of activation. The highest values of permittivity and magnetization were observed for Mn-doped SrTiO 3 ceramic mechanically activated for 120 min. Based on all the above, the optimal electrical and magnetic properties of SrTiO 3 ceramics can be achieved by the appropriate choice of mechanical activation time and dopant concentration. [ABSTRACT FROM AUTHOR]

Energy storage capacitors for advanced pulse power systems and high-power electric devices is a kind of important electronic components, the demand continues to grow, specifications are constantly being upgraded, and performance boundaries are continuously being pushed. Multilayer ceramic capacitors (MLCCs) for energy storage applications have received increasing attention due to the advantages of ultralow equivalent series inductance, equivalent series resistance, good frequency characteristics, strong voltage overload ability, and stable operability at high temperatures. However, the relatively low energy storage density significantly limits its broader applications. Here, 0.4Ba 0.55 Sr 0.45 TiO 3 -0.4Bi 0.5 Na 0.5 TiO 3 -0.2SrZrO 3 (0.4BST-0.4BNT-0.2SZ) relaxor ferroelectric MLCCs are prepared at different heating rates. Excellent recoverable energy storage density of 10.3 J cm−3 and high energy efficiency of 93 % are achieved in fast-fired MLCCs under the electric field of 106.3 V μm−1. The impedance spectroscopy and thermally stimulated depolarization current technologies are employed to investigate the conductance mechanism of MLCCs, and the results can explain the effect of heating rate on the performance of MLCCs. In addition, the charge-discharge performances of fast-fired MLCCs are also thoroughly investigated, exhibiting great thermal and fatigue stability. [ABSTRACT FROM AUTHOR]

The crystal structure, oxygen content and homogeneity range of Pr 1-x Sr x CoO 3-õ solid solutions from room temperature (RT) up to 1100 °C in air were studied. It has been shown that an increase in temperature and Sr content causes an Orthorhombic → Rhombohedral → Cubic transformation of the crystal structure. The heterovalent substitution of Sr2+ for Pr3+ is compensated by an increase in the mean oxidation state of Co ions (z Co) and the formation of oxygen vacancies. The temperature dependences of thermal expansion and conductivity of Pr 1-x Sr x CoO 3-õ solid solutions are explained from the point of view of crystal and defect structure. The diagram of phase relation in the PrCoO 3 – "SrCoO z " cross section has been constructed. [ABSTRACT FROM AUTHOR]

The development of lead-free dielectric capacitors with good energy storage performance and high reliability is of great practical significance for pulsed power systems. In this study, Nb 2 O 5 -modified 0.6(Bi 0.5 Na 0.5)TiO 3 -0.4(Sr 0.7 Bi 0.2)TiO 3 (BNT-SBT- x Nb, 0 ≤ x ≤ 0.07) ceramics were designed to enhance their energy storage performance and prepared using a hydrothermal method. The results show that Nb doping into the B site of BNT-SBT can induce lattice expansion and promote polar nanoregions, resulting in improved dielectric relaxation behavior. Moreover, the introduction of Nb can lead to the refinement of grain size, the increase in resistivity, the reduction of oxygen vacancies, and the broadening of band gap, thereby significantly enhancing the electrical breakdown strength (E b). Accordingly, the BNT-SBT-0.05Nb system presents excellent energy storage performance with high W rec ∼6.26 J/cm3 and η ∼87.9 % under an large E b of 518 kV/cm in accompany with the wide temperature stability (W rec and η vary within ±6.8 % and ±3.2 % at 40–100 °C). The significant improvement of E b and energy storage performance demonstrates that the BNT-SBT-0.05Nb system is a potential candidate for applications in high-energy storage capacitors. [ABSTRACT FROM AUTHOR]

The crystal structure of La 0.7 Sr 0.3 Mn 1−x Al x O 3 (LSMAO) with x = 0,0.025,0.05,0.075 and 0.10 ceramics prepared by the Sol-gel method were investigated by employing the XRD technique. The XRD patterns analysis by employing the Rietveld analysis confirms the nonexistence of secondary crystal phase/s and, materials are crystallized to the R-3c(167) space group. The microstructural properties were studied using scanning electron microscope (SEM) and transmission electron microscope (TEM). The dielectric property, AC conductivity, complex impedance spectroscopy and complex electrical modulus have been studied over a wide range of frequencies (103 Hz–107 Hz) at different temperatures from 313K to 393K. The Non-Debye type relaxation process has been observed in synthesized samples confirmed from the Nyquist plot. The Cole-Cole plots were employed to estimate the individual grain and grain boundary contributions. The Maxwell-Wagner (MW) polarization model provides an explanation for the greater values of dielectric constant at the lower frequencies. The present study explores the technological usefulness of LSMAO. [ABSTRACT FROM AUTHOR]

Modifying electrical and optical properties in two-carbon materials is essential for electronic devices, energy storage and biosensor applications. We report a comparative study of the effect of systematically intercalated strontium atoms in AA- and AB-stacked bilayer graphene (BG) in the framework of density functional theory (DFT). The electronic band structures, the total and partial electronic density of states and the dielectric function are studied. We show that the intercalation of atoms can influence both electronic properties. Our results show that the Dirac cones, a signature of graphene, are translated into the conduction band. This property may be useful in band-gap tuning applications of nanodevices. The optical properties were calculated parallel and perpendicular to the graphene sheet under polarised electric fields. The calculated optical properties show that the intercalation of Sr in the AA- and AB-stacked BGs promotes IR absorption. The findings provide a basis for developing graphene intercalary compounds, which can be used in optoelectronics to control the absorption of light wavelengths and specifically in biosensor applications. [ABSTRACT FROM AUTHOR]

Early Paleozoic A-type granites in South China are rare, and their petrogenesis is still highly debated. This study focuses on the controversial Epo pluton in the Wuyi-Yunkai Orogen and conducts petrological and petrogeochemical research to discuss its origin. The Epo granites were emplaced at approximately 414 Ma and exhibit petrological and geochemical features of A-type granites. They contain only one ferromagnesian mineral, ferrum biotite. The granites mostly have high alkalis contents (Na2O + K2O = 6.48–8.85 wt.%), high field strength element (HFSE) contents (Zr + Nb + Ce + Y = 353–461 ppm), and high Ga/Al (104×Ga/Al = 2.50–3.72) and FeOT/(FeOT + MgO) (0.74–0.85) ratios. Besides, they formed under high-temperature (>850°C) and low-pressure (≤5 kbar) conditions. Their high A/CNK (average 1.20) and Eu/Eu* (average 0.46) values as well as Sr (average 128 ppm) and Ba (average 628 ppm) contents but relatively low Zr contents (approximately 200 ppm) further suggest a strongly peraluminous A-type affinity, a distinctive subtype of A-type granites. The Epo granites display enriched Sr-Nd-Hf isotope compositions with a whole-rock87Sr/86Sri average ratio of 0.712, whole-rock εNd(t) values ranging from − 8.9 to − 7.6, and zircon εHf(t) values clustering at − 8. Their two-stage Nd and Hf isotope model ages are 1.7 Ga to 2.0 Ga, suggesting ancient crustal sources. Furthermore, Nb/U (average 7.46), Ce/Pb (average 4.06) and other trace element ratios indicate negligible contributions from juvenile mantle materials. Our data on the Epo pluton, coupled with other contemporary A-type granites in South China, suggest that the high-temperature melting of metasedimentary basements generated strongly peraluminous A-type granites, while the involvement of metaigneous rocks or mantle-derived magmas resulted in metaluminous to weakly peraluminous A-type granites. Source diversity leads to different aluminium saturations. The heat required to produce high-temperature A-type magmas was supplied by upwelling mantle-derived magma in a postcollisional extensional setting. [ABSTRACT FROM AUTHOR]

High‐temperature piezoelectric sensing is usually used in the aerospace, automotive, and power plant fields. High temperature piezoelectric ceramics are considered the key materials in these fields. In this paper, Ca1−x(Ba1/2Sr1/2)xBi2Nb1.985(W3/4Mn1/4)0.015O9 (x = 0.05, 0.10, 0.15 and 0.20) (C1−xBSxBNWM) has been synthesized by a traditional solid state reaction method. The effects of substitution of calcium at the A‐site by barium and strontium on phase evolution and piezoelectric properties of the CaBi2Nb2O9 orthorhombic Aurivillius phases were investigated. The crystal structure of piezoelectric ceramics was characterized by XRD, Rietveld refinement, and Raman spectroscopy. Co‐substitution of barium/strontium (Ba2+/Sr2+) and tungsten/manganese (W6+/Mn4+) resulted in lattice distortion of C1−xBSxBNWM ceramics. The results induce that the tetragonal crystal structure increase with increasing the co‐substitution cations. Isothermal impedance spectroscopy confirmed intrinsic thermally activated conduction in the system. The C1−xBSxBNWM ceramics with x = 0.15 exhibit a very high Curie temperature (TC ∼ 923°C), a reasonable piezoelectric coefficient (d33 = 13.3 pC/N). Remarkably, even after thermal annealing at temperatures up to 800°C, it still retains a high d33 of 13 pC/N. In addition, the C0.85BS0.15BNWM ceramic had a relatively high resistivity (3.82 × 106 Ω·cm, 500°C). The Ca0.85(Ba1/2Sr1/2)0.15Bi2Nb1.985(W3/4Mn1/4)0.015O9 ceramics make possible their application in high‐temperature acceleration transducers. [ABSTRACT FROM AUTHOR]

Doping Sr has the potential to enhance bioceramic properties. However, controlling purity, Sr concentration, and properties is crucial. Therefore, precise evaluation of synthesis variables is essential, achieved through experimental design techniques. This study synthesized Sr-doped calcium silicate wollastonite using a Plackett–Burman design with 11 variables to identify key factors affecting synthesis yield and physical, structural, and chemical attributes for tissue engineering. Results indicate that the strontium proportion significantly impacts material properties, affecting porosity, surface area, and pore volume. Moreover, observations reveal that calcination temperature contributes to heightened crystallinity and strontium doping. Adjusting calcium and strontium precursor concentrations while reducing the silicon to calcium and strontium ratio improves efficiency crystallinity, purity, and promotes the formation of the preferred β-CaSiO 3 phase. Overall, consistent and reproducible findings provide valuable insights into the variables influencing the process and facilitate optimization for future ceramic synthesis. [Display omitted] [ABSTRACT FROM AUTHOR]

Subacute ruminal acidosis (SARA) is a common nutritional metabolic disease in ruminants that causes significant economic losses to dairy farming. Strontium (Sr) is known to be involved in bone metabolism and exhibits potent anti-inflammatory effects. To evaluate the effect of Sr on inflammation in bovine ruminal epithelial cells, a model of LPS-induced inflammation was established in this study, and the cell viability of bovine ruminal epithelial cells was measured using CCK-8. The production of pro-inflammatory cytokines was measured by ELISA and real-time PCR, respectively. The related proteins of the TLR4/MyD88/NF-κB pathway were assayed through Western blotting, and the fluorescence of p-p65 and p-IκB were assayed by immunofluorescence. Molecular docking of Sr and TLR4/MyD88/NF-κB pathway-related proteins was performed using MIB2 (http://bioinfo.cmu.edu.tw/MIB2/). Results showed that after treatment for 24 h, the cell viability was decreased at the high concentration of Sr (≥ 10 mmol/L). Sr significantly decreased the production of TNF-α, IL-1β, and IL-6, downregulated the related proteins expression of the TLR4/MyD88/NF-κB pathway, and reduced the fluorescence levels of p-p65 and p-IκB. The NF-κB pathway inhibitor PDTC and molecular docking further revealed that Sr reduced LPS-induced pro-inflammatory cytokines production via the TLR4/MyD88/NF-κB pathway. These results suggest that Sr reduces LPS-induced pro-inflammatory cytokines production via the TLR4/MyD88/NF-κB pathway, thereby exerting an anti-inflammatory effect in bovine ruminal epithelial cells, providing a basis for Sr in the treatment of bovine rumen acidosis disease. [ABSTRACT FROM AUTHOR]

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

Highlights SrAl2O4 co‐doped with Eu2+ and Dy3+ ions (SAOED) have great potential in lighting field due to the unique light energy absorption‐storage‐released properties. In this work, a series of SAOED/poly(methyl methacrylate) (PMMA) luminescent composites were prepared and investigated. The maximum afterglow intensity of SAOED/PMMA composites was reached when the SAOED particle size was 26 μm, the mass ratio of SAOED to PMMA was 0.6 and the thickness of composites was 4.3 mm. Meanwhile, the tensile strength and modulus of the SAOED/PMMA composites were 22.06 MPa and 3.92 GPa, respectively. After being reexcited by a 3.5 W white diode used as normal functional lighting, SAOED/PMMA composites were able to achieve the requirement on landscape lighting (>2 lx), which showed promising engineering prospects in alternative lighting. The particle size, mass ratio and thickness effected the afterglow intensity. The optimal composites presented promising long persistent luminescence. Resulting SrAl2O4 co‐doped with Eu2+ and Dy3+ ions (SAOED)/poly(methyl methacrylate) (PMMA) composites possessed high tensile performance. The SAOED/PMMA composites showed great potential in alternative lighting. [ABSTRACT FROM AUTHOR]

BACKGROUND: As a bone replacement and filling material, calcium phosphate stone bone cement has good biocompatibility, bone conductivity, and other advantages, especially its better biodegradability compared to other calcium phosphate bone cements. It has important application value in bone repair. However, due to its limitations such as insufficient mechanical properties, fast solidification reaction, and poor injection performance, it is currently only suitable for the repair of non weight-bearing bone. OBJECTIVE: To explore the modification of brushite cements with bioactive ions (metal and non metal ions) to expand its application range. METHODS: The author used PubMed, ScienceDirect, CNKI, and WanFang to search the literature published between 2018 and 2023 with the search terms “metal ion, iron, copper, strontium, magnesium, zinc, non-metal ion, modification, bone, brushite cements” in Chinese and “metal ion, iron, Fe, copper, Cu, strontium, Sr, magnesium, Mg, zinc, Zn, non-metal ion, modification, bone, brushite cements” in English. After reading titles and abstracts, the articles were initially screened, and irrelevant and duplicate articles were excluded. Finally, 64 articles were included for review. RESULTS AND CONCLUSION: (1) Bioactive ions affect the hydration process of calcium phosphate bone cement. Different ions are substituted by ions and incorporated into the crystal structure of calcium phosphate bone cement, changing the crystal morphology of the cement and causing changes in physical and chemical properties such as setting time, injectability, and compressive strength. (2) Ionic modified calcium phosphate bone cement produces different ion release effects due to different crystal structures. Different types of ions have properties such as promoting angiogenesis/osteogenesis, antibacterial, antitumor, etc. In addition, calcium phosphate bone cement has good biodegradability, which has great advantages for the performance of various ions. (3) The physicochemical properties of calcium phosphate bone cement modified with different ions are as follows: iron, copper, strontium, magnesium, zinc, silver, and cobalt can prolong the setting time. Strontium, and magnesium can improve injection performance. Copper, strontium, magnesium, silver and silicon can enhance compressive strength. The ions that can simultaneously improve the three physical and chemical properties of calcium phosphate bone cement include strontium and magnesium. Good physical and chemical properties are a prerequisite for clinical application, so improving the setting time, injectability, compressive strength, and other properties of calcium phosphate bone cement with ions is of great significance for the research and application of bone cement. (4) The biological properties of calcium phosphate bone cement modified with different ions are as follows: copper, strontium, magnesium, zinc, cobalt, lithium, selenium, and silicon have promoting angiogenesis/osteogenic effects. Iron, copper, magnesium, zinc, and silver have antibacterial properties. Magnesium ions have anti-inflammatory properties. Copper and selenium have anti-tumor properties. (5) In summary, magnesium ions can improve the setting time, injectability, and compressive strength of calcium phosphate bone cement, while also promoting neovascularization/osteogenesis, antibacterial properties, and have good application prospects for the treatment of bone defects with concurrent infections. In addition, copper also has anti-tumor properties, so copper ions have great potential in the treatment of bone defects caused by infections and tumors. However, relevant research is still in the basic research stage, and the effects of different ion doping concentrations and synthesis conditions on the physicochemical properties of calcium phosphate bone cement need to be further explored. At the same time, the impact of biological properties also needs to be studied and observed for a longer period of time. [ABSTRACT FROM AUTHOR]

Migratory patterns of the catfish Genidens genidens in four estuaries along the Brazilian Atlantic coast are reconstructed from otolith Sr/Ca, a salinity proxy, to test estuarine‐dependency. To facilitate interpretation of this proxy in otolith core‐to‐edge profiles, a Sr/Ca Reference Value for High Salinity (RVHSSr/Ca) of 4.88 mmol/mol was established experimentally, from fish specimens reared in water with a salinity level (33 psu) between estuarine and high salinity (marine) water. All wild specimens exhibited otolith Sr/Ca values higher than RVHSSr/Ca, suggesting that G. genidens utilizes environments with marine salinity. Our results reveal highly variable environmental histories, with at least five major habitat usage patterns. Most distinctive among these, we find that (a) fish from Paranaguá Estuarine Complex (PEC) exhibit high intraindividual heterogeneity; (b) most fish (57%) from Guanabara Bay (GB) exhibit prolonged exposure to very high salinities, often exceeding 36.5 psu levels found in some shelf sectors; and (c) some fish from Paraiba do Sul River, GB and PEC exhibit Sr/Ca values below RVHSSr/Ca consistent with estuarine residence. These results suggest that G. genidens is not strictly estuarine‐dependent. [ABSTRACT FROM AUTHOR]

Osteoporosis is the most common bone disease both worldwide and in the United States, and generally remains subclinical until the occurrence of fracture. With osteoporotic fractures being a substantial source of morbidity and mortality, effective therapies for slowing the decline of bone density in affected individuals are much needed. The standard therapy of osteoporosis may include medication, fall prevention, smoking cessation, avoidance of excess alcohol intake, calcium, and weight-bearing exercise. This article reviews complementary or integrative approaches with evidence for use in osteoporosis. This includes strontium, choline-stabilized orthosilicic acid, isoflavones (including ipriflavone and soy isoflavones), vitamin D, and vitamin K. [ABSTRACT FROM AUTHOR]

Methane is a highly potent greenhouse gas, and its mitigation is deliberately needed. The partial oxidation of methane (POM) is a promising route for depleting methane with a high H2/CO ratio through direct and indirect reaction pathways. In this study, the catalyst Ni stabilized over titania-zirconia support is found to retain the catalytic active sites exposed for a constant 30% H2 yield with an H2/CO ratio of 4.25 up to 300 h. Furthermore, the promotion role of 2wt% Cs, Ce, Sr over Ni/TiZr catalyst is studied for POM reaction where 2wt% Cs addition to Ni/TiZr is found to be decremental toward POM due to the lowest density of basic sites. 2wt% Sr promoted Ni/TiZr performs best due to the highest edge of reducibility, the highest population of active sites, and retention of active sites in a reduced state against O2 during POM reaction. It ensures > 45% CH4 conversion, > 40% H2 yield, and 3.7 H2/CO ratio at 600 °C during the 300-min time on stream. At high reaction temperature (750 °C) over NiSr/TiZr catalyst, the H2/CO ratio is dropped to ~ 2 and the H2 yield is jumped to 97% indicating the exclusive presence of a direct pathway for POM. [ABSTRACT FROM AUTHOR]

Reaction of lithium 1,3‐diamidopropane Li2(TripNCN) (TripNCN=[{(Trip)NCH2}2CH2]2−, Trip=2,4,6‐triisopropylphenyl) with BeBr2(OEt2)2 gave the diamido beryllium complex, [(TripNCN)Be(OEt2)]. Deprotonation reactions between the bulkier 1,3‐diaminopropane (TCHPNCN)H2 (TCHPNCN=[{(TCHP)NCH2}2CH2]2−, TCHP=2,4,6‐tricyclohexylphenyl) and magnesium alkyls afforded the adduct complexes [(TCHPNCN)Mg(OEt2)] and [(TCHPNCN)Mg(THF)2], depending on the reaction conditions employed. Treating [(TCHPNCN)Mg(THF)2] with the N‐heterocyclic carbene :C{(MeNCMe)2} (TMC) gave [(TCHPNCN)Mg(TMC)2] via substitution of the THF ligands. Reactions of (ArNCN)H2 (Ar=Trip or TCHP) with Mg{CH2(SiMe3)}2, in the absence of Lewis bases, yielded the N‐bridged dimers [{(ArNCN)Mg}2]. Salt metathesis reactions between alkali metal salts M2(TCHPNCN) (M=Li or K) and CaI2 or SrI2 led to the THF adduct compounds [(TCHPNCN)Ca(THF)3] and [(TCHPNCN)Sr(THF)4], the differing number of THF ligands in which is a result of the different sizes of the metals involved. The described complexes hold potential as precursors to kinetically protected, low oxidation state group 2 metal species. [ABSTRACT FROM AUTHOR]

The spectra of singly ionized Strontium and Yttrium (Sr  ii and Y  ii) have been proposed as identifications of certain spectral features in the AT2017gfo spectrum. With the growing demand for non-local-thermodynamic-equilibrium (NLTE) simulations of Kilonovae, there is an increasing need for atomic data for these and other r -process elements. Our goal is to expand upon the current set of atomic data for r -process elements, by presenting transition probabilities and Maxwellian-averaged effective collision strengths for Sr  ii and Y  ii. The Breit–Pauli and darc R -matrix codes are employed to calculate the appropriate collision strengths, which are thermally averaged according to a Maxwellian distribution to calculate excitation and de-excitation rates. The tardis and ColRadPy packages are subsequently used to perform local thermodynamic equilibrium (LTE) and NLTE modelling, respectively. A complete set of transition probabilities and effective collision strengths involving levels for Sr  ii and Y  ii have been calculated for temperature ranges compatible with kilonova plasma conditions. Forbidden transitions were found to disagree heavily with the Axelrod approximation, an approximation which is currently employed by other models within the literature. Theoretically important spectral lines are identified with both LTE and NLTE modelling codes. LTE simulations in tardis reveal no new significant changes to the full synthetic spectra. NLTE simulations in ColRadPy provide indications of which features are expected to be strong for a range of regimes, and we include luminosity estimates. Synthetic emission spectra over kilonova densities and temperatures reveal potentially interesting spectral lines in the NIR. [ABSTRACT FROM AUTHOR]

It has been demonstrated that Sr is a beneficial additive element to Mg alloys and could effectively upgrade the properties of Mg alloys. However, the local structure and thermophysical properties of Mg–Sr, which are important properties of the alloy, have rarely been reported. This work applied atomistic simulations, assisted by deep learning potential (DPL), conducted on the Mg–Sr liquid alloy to reveal its local structure and thermophysical properties. The reliability of the trained DPL model was thoroughly validated by the root-mean-square errors, energy and force comparison results, and local structure reproducibility. The radial distribution function and structural factor were adopted to assess the short-range and intermediate-range ordering of the Mg–Sr liquid alloy, whose component and temperature dependence were analyzed. Mg–Sr alloy is more compact in the Mg-rich system; all the ordering is temperature-negatively dependent. Densities, self-diffusion coefficients, and shear viscosities of Mg–Sr liquid alloys containing different Mg concentrations, covering the temperature range of 1100–1400 K, were predicted by deep learning molecular dynamics simulation, and the corresponding databases were established. The enthalpies of mixing and elemental activities of Mg–Sr liquid alloys at 1100 K were reliably evaluated. The mixing enthalpy is less than zero, and the dependence of the Mg and Sr activities on the Mg concentration presents a downward concave shape that deviates from Raoul's law, forming a negative deviation. Overall, this present study provides theoretical foundation and directional guidance for the development of Mg–Sr alloys. [ABSTRACT FROM AUTHOR]

Reindeer are part of the faunal suite that dominated central Europe during the last glacial cycle. Their importance to Late Gravettian hunters as prey and a source of raw materials (hide, bone, antler) is well attested, however the context of Late Gravettian reindeer predation is lesser understood. This paper presents an investigation of human and reindeer predator-prey interactions at the Late Gravettian kill-butchery site of Lubná VI, Czech Republic. We reconstruct seasonal mobility (87Sr/86Sr, δ18O), diet (δ13C, δ15N) and season of death (dental cementum) of up to nine reindeer prey, to inform on the strategic choices made by Late Gravettian hunters. Results indicate that most hunted reindeer lived year-round in the foothills of the Bohemian-Moravian highlands near where Lubná is located, at altitudes between ~ 200–450 m above present sea level, while a smaller number showed evidence of seasonal migration between this area and the open plains of the Elbe river corridor (Bohemian Cretaceous basin). No evidence for long distance migration of reindeer was detected, indicating that productive local environments were supporting reindeer herds within a single annual territory. Meanwhile, areas higher than ~ 450 m above present sea level were avoided entirely by all analysed individuals, consistent with these areas being topographic barriers to movement due to climate severity. We conclude that hunters visited Lubná as part of a logistically-organised subsistence strategy, deliberately targeting reindeer in late autumn when fat supplies, hides and antler are in prime condition knowing that they would reliably encounter their prey at this location. [ABSTRACT FROM AUTHOR]

The sensitive response of antiferromagnetic order to As ions height in pressure environment makes the reduction of As ions height beneficial for rapid suppression of antiferromagnetism. The analysis from lattice parameters and electron density indicates that As ions height has a significant impact on antiferromagnetic suppression. The interrelationship between As ions height and antiferromagnetic suppression makes it easier for uniaxial pressure along the c‐axis environments to suppress antiferromagnetism, cause Lifshitz transition compared and induce Fermi surface nesting than uniaxial pressure along the a‐axis (or b‐axis) environments, which can explain the fluctuation of superconducting critical pressure measurements in experiments with uneven pressure application from a microscopic perspective. [ABSTRACT FROM AUTHOR]

Objectives: To explore the antimicrobial potential of strontium (Sr)‐functionalized wafers against multiple bacteria associated with per‐implant infections, in both mono‐ and multispecies biofilms. Materials and Methods: The bactericidal and bacteriostatic effect of silicon wafers functionalized with a strontium titanium oxygen coating (Sr‐Ti‐O) or covered only with Ti (controls) against several bacteria, either grown as a mono‐species or multispecies biofilms, was assessed using a bacterial viability assay and a plate counting method. Mono‐species biofilms were assessed after 2 and 24 h, while the antimicrobial effect on multispecies biofilms was assessed at Days 1, 3, and 6. The impact of Sr functionalization on the total percentage of Porphyromonas gingivalis in the multispecies biofilm, using qPCR, and gingipain activity was also assessed. Results: Sr‐functionalized wafers, compared to controls, were associated with statistically significant less viable cells in both mono‐ and multispecies tests. The number of colony forming units (CFUs) within the biofilm was significantly less in Sr‐functionalized wafers, compared to control wafers, for Staphylococcus aureus at all time points of evaluation and for Escherichia coli at Day 1. Gingipain activity was less in Sr‐functionalized wafers, compared to control wafers, and the qPCR showed that P. gingivalis remained below detection levels at Sr‐functionalized wafers, while it consisted of 15% of the total biofilm on control wafers at Day 6. Conclusion: Sr functionalization displayed promising antimicrobial potential, possessing bactericidal and bacteriostatic ability against bacteria associated with peri‐implantitis grown either as mono‐species or mixed in a multispecies consortium with several common oral microorganisms. [ABSTRACT FROM AUTHOR]

Divalent cations have captured the interest of researchers in biomedical and dental fields due to their beneficial effects on bone formation. These metallic elements are similar to trace elements found in human bone. Strontium is a divalent cation commonly found in various biomaterials. Since strontium has a radius similar to calcium, it has been used to replace calcium in many calcium-containing biomaterials. Strontium has the ability to inhibit bone resorption and increase bone deposition, making it useful in the treatment of osteoporosis. Strontium has also been used as a radiopacifier in dentistry and has been incorporated into a variety of dental materials to improve their radiopacity. Furthermore, strontium has been shown to improve the antimicrobial and mechanical properties of dental materials, promote enamel remineralization, alleviate dentin hypersensitivity, and enhance dentin regeneration. The objective of this review is to provide a comprehensive review of the applications of strontium in dentistry. [ABSTRACT FROM AUTHOR]

To tackle the question of the reliability of otoliths as recorders of individual life events, we compared the information enclosed in otolith pairs: the sagittae pair and the sagitta/lapillus pair. We used the synchrotron XRF scanning imaging method, which enabled the comparison of this information at both global and hyperfine scales. Using otoliths of diadromous pipefish, we compared element incorporation in each pair with a focus on (i) environment and transition between water bodies with strontium (Sr) and heavy metals, (ii) temporal information and age estimation based on sulphur (S) incorporation, and (iii) otolith growth and biomineralization processes with zinc (Zn). Results show that the global information in terms of Sr and heavy metals given by both otoliths of a pair is the same and that any otolith may be used to retrieve such global data. In terms of S-based growth increment counts, the numbers are the same between two otoliths of the same kind, but the sagitta/lapillus pairs show a significant difference. Hyperfine-scale analysis of element distribution reveals that a given otolith is under the control of specific growth mechanisms, which can lead to heterogeneous elemental incorporation. The present results lead us to consider otolith growth dynamics and biomineralization processes in the context of a fluid mosaic perspective. [ABSTRACT FROM AUTHOR]

Boron to calcium (B/Ca) records in benthic foraminifera, used for reconstructing the carbonate ion saturation state (ΔCO3) of the deep ocean, suggest that carbon sequestration in the Southern Pacific contributed to lowering atmospheric CO2 during the last glacial interval. However, the spatial and temporal extent of this storage is debated due to limited ΔCO3 records. To increase available ΔCO3 records, we explored using strontium and sulfur to calcium (Sr/Ca, S/Ca) in Planulina wuellerstorfi as additional proxies for ΔCO3 based on comparison with paired B/Ca down‐core records from Pacific Sites U1486 (1,332 m depth) and U1487 (874 m depth) cored during the International Ocean Discovery Program Expedition 363. The Sr/Ca and S/Ca records from P. wuellerstorfi closely covary with the B/Ca‐derived ΔCO3 records. Temperature, reconstructed using Uvigerina peregrina magnesium to calcium (Mg/Ca), has no discernible effect on Sr/Ca, whereas S/Ca also varies with Mg/Ca in both U. peregrina and P. wuellerstorfi, suggesting an additional temperature effect. Mg/Ca records from P. wuellerstorfi are affected by both temperature and ΔCO3. We assess calibrations of Sr/Ca to ΔCO3 for the Atlantic, Pacific, and Indian Oceans and recommend using the down‐core rather than core‐top calibrations as they yield consistent sensitivity, though with offsets, in all ocean basins. Reconstructing Pacific ΔCO3 records from sites U1486, U1487, and DSDP 593, we demonstrate the benefit of using Sr/Ca as an additional ΔCO3 proxy to assess the contribution of the Southern Pacific to the increase of atmospheric CO2 at glacial terminations. Plain Language Summary: Burning of fossil fuels has increased since the industrial revolution, resulting in the addition of CO2, a gas which retains heat, to the atmosphere. Understanding how the earth's oceans work to regulate levels of atmospheric CO2 is key to understanding the effects of increased atmospheric CO2 on the earth's climate. The carbonate system in the ocean, of which CO2 is a component, is complex. Carbonate saturation state (ΔCO3) is a measure of how close the carbonate ion concentration is to the level at which calcite (which makes up the shell or test of some single‐cell organisms) will dissolve. It is related to the level of ocean storage of CO2. Boron to calcium ratios (B/Ca) found in test calcite have been used as a proxy for past ocean ΔCO3, but these records are limited. Here, to increase presently available ΔCO3 proxy records, we explore using strontium and sulfur to calcium (Sr/Ca, S/Ca) as additional proxies for ΔCO3. Unlike S/Ca, Sr/Ca shows no temperature influence, so makes a useable proxy for change in ΔCO3. Sr/Ca records can be used to infer the progressive release of oceanic CO2 to the atmospheric at three terminations, periods in the past when atmospheric CO2 increased dramatically. Key Points: Sr/Ca ratios in P. wuellerstorfi show no detectable influence of temperature and are useful for reconstructing changes in ΔCO3S/Ca ratios in P. wuellerstorfi may potentially be used to reconstruct a long‐term (e.g., Cenozoic) record of sulfate in the oceanSr/Ca derived ΔCO3 records suggest CO2 release from upper water and then from progressively deeper water during the last three terminations [ABSTRACT FROM AUTHOR]

Radioactive nuclides cesium (Cs) and strontium (Sr) possess long half-lives, with 135Cs at approximately 2.3 million years and 87Sr at about 49 billion years. Their persistent accumulation can result in long-lasting radioactive contamination of soil ecosystems. This study employed geo-accumulation index (Igeo), pollution load index (PLI), potential ecological risk index (PEPI), health risk assessment model (HRA), and Monte Carlo simulation to evaluate the pollution and health risks of Cs and Sr in the surface soil of different functional areas in a typical mining city in China. Positive matrix factorization (PMF) model was used to elucidate the potential sources of Cs and Sr and the respective contribution rates of natural and anthropogenic sources. The findings indicate that soils in the mining area exhibited significantly higher levels of Cs and Sr pollution compared to smelting factory area, agricultural area, and urban residential area. Strontium did not pose a potential ecological risk in any studied functional area. The non-carcinogenic health risk of Sr to the human body in the study area was relatively low. Because of the lack of parameters for Cs, the potential ecological and human health risks of Cs was not calculated. The primary source of Cs in the soil was identified as the parent material from which the soil developed, while Sr mainly originated from associated contamination caused by mining activities. This research provides data for the control of Cs and Sr pollution in the surface soil of mining city. [ABSTRACT FROM AUTHOR]

Re3+ ions (Re = Y, La, Gd)-doped MSi2O2N2:Eu2+ (M = Ca, Sr) phosphors were prepared by the solid-state reaction method. The effects of co-dopants (Y3+, La3+, Gd3+) and Eu2+ doping concentration on the luminescent performance of MSi2O2N2:Eu2+ have been investigated. The co-doping with Re3+ (Re = Y, La, Gd) significantly improved the luminescent performance of MSi2O2N2:Eu2+ (M = Ca, Sr) overall. Re3+ co-doping had a greater enhancing effect on higher Eu2+ concentration samples and the Re3+-doped CaSi2O2N2:Eu2+ phosphors exhibited better luminescence properties than Re3+-doped SrSi2O2N2:Eu2+ ones. In addition, incorporation of Y3+ ions to SrSi2O2N2:Eu2+ showed the strongest emission among the three dopants (Y3+, La3+, and Gd3+), while the Gd3+ doping ions in CaSi2O2N2:Eu2+ exhibited superior luminescence properties compared to Y3+ and La3+. [ABSTRACT FROM AUTHOR]

(1 − x)(K0.5Na0.5)NbO3-xSr(Bi0.5Nb0.5)O3 (KNN-xSBN, x = 0.02, 0.03, 0.04, 0.05, 0.06, 0.07) ceramics were designed and prepared by solid-phase method. The effects of different SBN content in solid solution on the transmittance, microstructure, phase structure, ferroelectric properties, and energy storage properties of ceramic samples were studied. After adding the second component SBN, the phase structure of KNN ceramics changes from tetragonal phase structure to cubic phase structure, and the grain size reaches the micron level, so that it exhibits good light transmittance and also retains good ferroelectricity, energy storage, and other performance parameters. It is a multifunctional material with excellent performance. When x = 0.06, the transmittance of the ceramic sample is the highest; the transmittance in the visible light band (780 nm) reaches 64.64%, and the transmittance in the near-infrared band reaches 71.68% (1100 nm); when x = 0.07, energy storage efficiency η reaches 74%. [ABSTRACT FROM AUTHOR]

Magnetic tunnel junction (MTJ) is one of the cornerstones of modern information technologies. Bringing MTJ's operation beyond the conventional binary regime, enabled by tunneling magnetoresistance (TMR) effect, is highly promising for prospective memory technologies and neuromorphic hardware development. In this paper, we demonstrate multilevel magnetoresistance states in an all-perovskite-oxide La0.7Sr0.3MnO3 (LSMO)/BaTiO3/LSMO heterostructure grown on MgO substrates. Unlike traditional TMR, we observe four distinct regions of increased magnetoresistance, which result in three magnetic field-induced resistance states in total. We show that the observed phenomenon arises from the low-field magnetoresistance effect, which occurs in the two epitaxial LSMO layers, independently and at different values of the magnetic field. The effect is well simulated by a model based on the presence of structural defects and non-uniform deformations in the LSMO layers, induced by the large lattice mismatch of the LSMO with the MgO substrate. We believe that our findings contribute to the understanding of complex magnetoresistance effects in MTJs and can be taken into consideration for the design of multi-bit memory cells or neuromorphic devices. [ABSTRACT FROM AUTHOR]

Numerous hybrid improper ferroelectrics have been discovered in bulk oxides with layered perovskite structures. In contrast, the competition between the interlayer rumpling and oxygen octahedral rotation suppresses the ferroelectricity in layered perovskite material with trivalent cation at the B-site. In the present work, single-phase dense La2Sr(Sc1−xFex)2O7 ceramics with double-layered Ruddlesden–Popper structures have been prepared, and room-temperature ferroelectricity is discovered in the ceramics with x ≤ 0.10. The ferroelectric polarization and coercive field decrease with increasing content of Fe3+ cations, consistent with the decline of oxygen octahedral rotation and tilting angles. Although the linear relationship between the Curie temperature and the tolerance factor for La2Sr(Sc1−xFex)2O7 ceramics is established, the line is far away from that for A2+3B4+2O7 ceramics due to the large interlayer rumpling in the present ceramics. Although no single-phase multiferroic has been discovered in this work, an effective way to introduce magnetism into hybrid improper ferroelectric is provided. [ABSTRACT FROM AUTHOR]

The drawbacks of high temperature solid oxide fuel cells (HT‐SOFCs) prompt efforts to lower operating temperatures to near ambient temperatures (NAT). Here the high mixed OH−/H+ ionic conductivity in doped SrCeO3 below 100 °C is reported. The SrCe0.8Y0.2O3−δ (SCYO20) electrolyte demonstrates a high ionic conductivity of 12 mS cm−1 in water and 9 mS cm−1 in wet air at 60 °C and an excellent long‐term stability over 100 h. Solid state nuclear magnetic resonance confirms the presence of protons and hydroxide ions in the hydrated oxides and their correlation with Y dopant. Demonstration of direct ammonia fuel cells using the SCYO20 electrolyte indicates the practical application value of this material. The OH− conduction of SrCe0.7Sn0.2Y0.1O3−δ (SCSY721) is demonstrated by electrolysis of D2O. The introduction of KOH significantly increases the availability of OH− feed ions, leading to a remarkable improvement of ionic conductivity of SCSY721 electrolyte which is increased by 27 times, 56.34 mS cm−1 in 6 m KOH at 90 °C. The increased ionic conductivity due to the presence of high concentration of extrinsic conducting ions, here are OH− ions, is called as ‘feeding effect’. This study offers new electrolyte materials for cost‐effective, and durable electrochemical devices such as NAT‐SOFCs. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) phosphor‐converted light–emitting diodes (pc‐LEDs) are increasingly used in night vision, surveillance, and biomedicine. A major challenge is to identify a phosphor that efficiently converts blue light into wideband NIR emission. In this paper, a rare‐earth divalent europium (Eu2+)‐activated halogen oxide (Sr3GeO4Cl2) phosphor is unlocked via a high‐temperature solid‐state reaction. The Sr3GeO4Cl2:Eu2+ phosphor emits a wide spectrum (500–950 nm) with a peak at 700 nm when excited by 450 nm blue light. Extended X‐ray absorption fine structure (EXAFS) analysis reveals that the NIR emission primarily originates from Eu2+ ions, and the Eu─O bond length closely resembles the Sr─O bond length. Lattice engineering, specifically Ge/Si cation substitution, increased Eu2+ incorporation into the crystal lattice, boosting luminescence intensity by 75%–122% and quantum efficiency from 15% to 26%. This is related to the combined effect of reduced non‐radiative energy transfer and changes in the local lattice structure of Eu2+. A NIR pc‐LED device using the optimized phosphor showed a photoelectric efficiency of 16.5% and an optical output of 25.07 mW at 100 mA. This study not only explores new Eu2+‐activated NIR phosphors but also highlights the importance of crystal engineering to enhance luminescence properties, guiding future research for efficient NIR pc‐LED development. [ABSTRACT FROM AUTHOR]

Spinel materials are attractive to photocatalytic degradation of contaminants. In this study, strontium (Sr) doped spinel cobalt chromite (CoCr 2 O 4) was synthesized by solution combustion method and characterized using techniques such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and electrochemical impedance spectroscopy (EIS). 30 -50 nm-cubic CoCr 2 O 4 nanocrystals were obtained, and phase transitions of CoO 6 →CoO 4 and CrO 4 →CrO 6 occurred as the Sr doping content increased until 0.6 % Sr doped sample displayed an inverse spinel phase. The modifications in composition and structure induced the co-existence of multivalent states for Co and Cr, which in turn changed the optical, complex impedance, and magnetic spin state of CoCr 2 O 4. The 0.6 % Sr-doped sample showed the highest photocatalytic efficiency of 93 % due to enhanced optical absorption, reduced energy band gap, oxygen vacancies formation, and a high spin state of Co. The XRD structure and photocatalytic activity remained stable even after five cycles without any leakage of metal elements. The degradation pathway and Mott-Schottky curves were employed to elucidate the mechanism behind this enhancement. The strategy employed in this study proved effective, and the synthesized materials show promise for the photocatalytic degradation of contaminants. [ABSTRACT FROM AUTHOR]

The lead-free piezoelectric ceramics used in piezoelectric actuators have attracted extensive attention owing to their substantial electric-field-induced strain. In this study, The (1- x)Bi 0.5 (Na 0.41 K 0.09)TiO 3 - x Sr(Hf 0.5 Sb 0.4)O 3 (BNKT- x SHS) piezoelectric ceramics were synthesized using the conventional solid-state reaction method. The impact of SHS substitution on the microstructure and electrical properties was systematically explored. Among them, the BNKT-0.015SHS sample, featuring ergodic relaxor states, demonstrates a high piezoelectric strain coefficient (d 33 *) of 785 p.m./V under a low electric field of 50 kV/cm(Strain = 0.392 %). It exhibits a repeatable strain value of 0.47 % under an 80 kV/cm electric field(d 33 * = 590 p.m./V). Moreover, the strain values remain around 0.4 % between room temperature and 100 °C, with variations within 90 %. The heightened repeatable strain response is considered to be linked to the electric field-induced reversible phase transition occurring within the ergodic relaxor state. The higher strain temperature stability is ascribed to the coexistence of quadrilateral polar nanoregions and rhombic polydomain nanoregions. This study provides an effective example for achieving significant strain responses, presenting a feasible candidate material for applications in piezoelectric actuators. [ABSTRACT FROM AUTHOR]

Developing low-cost and high-efficiency non-precious metal cocatalysts is the key to the practical application of photocatalysis technology. Here, nickel sulfide (NiS) nanoparticles were synthesized on the surface of strontium titanate (SrTiO 3) via a hydrothermal method, identifying the optimal loading molar concentration of NiS as 10 %. The solar-to-hydrogen efficiency (STH) of 10%NiS/SrTiO 3 :Al was enhanced by 97 times compared to SrTiO 3 :Al and by 1.62 times compared to RhCrCoO x /SrTiO 3 :Al. This improvement is primarily attributed to the metallic-like properties of NiS, which enhance the photocatalyst's light absorption capacity and charge transfer capability. Additionally, the STH value of samples loaded with both NiS and RhCrCoO x reached 0.436 %, indicating a positive synergistic effect in photocatalysis between NiS and RhCrCoO x. Their photocathodic protection capability was also studied in simulated seawater conditions, showing a reduced self-corrosion potential (−0.31V) and a low interface charge impedance (5962 KΩ). This work reveals the potential of NiS as an alternative to precious metal cocatalysts, offering new possibilities for developing cost-effective and high-performance materials for photocatalytic water splitting and photocathodic protection. [ABSTRACT FROM AUTHOR]

The pursuit of efficient materials for technological applications is essential. Among these materials, zirconia emerges as a promising candidate with potential for several applications, from applications related to mechanical resistance to optoelectronic applications. By introducing dopants into this compound, it becomes feasible to modulate its inherent properties. In this study, ZrO 2 doped with strontium was synthesized for the first time via the sonochemical method at different percentages in mol (1, 2, 4, and 8 mol%). Analysis via X-ray diffraction (XRD) and Raman spectroscopy unveiled the formation of both monoclinic and tetragonal phases, with the latter being stabilized through the incorporation of the dopant element. In addition to observing irregular morphology through scanning electron microscopy (SEM-FEG), a reduction in particle size was also evidenced following the introduction of Sr2+ ions, a phenomenon corroborated via Rietveld refinement. The reflectance spectra of the doped samples exhibited an optical absorption tail characterized by the Urbach energy (E U), indicating an increase in structural disorder in the samples. The photoluminescence (PL) results indicated that the introduction of Sr2+ ions into the ZrO 2 matrix induced modifications in the characteristics of the spectrum profile. The phase transformation observed in XRD was reflected in the changes observed in the photoluminescent behavior of the samples, which emitted light between the blue and green regions. [ABSTRACT FROM AUTHOR]

This research meticulously explores the synthesis, structural, thermal and optical characterization of zinc oxide nanoparticles (NPs) infused strontium borate glasses (termed SZ glasses) and their applicability as radiation shielding. The glasses have been produced using the melt quenching process in the composition series of (60-x)B 2 O 3 : xZnO: 10SrO: 10Na 2 O: 10CaO: 10BaO, where x varied from 0 to 20 % mol. In order to dope ZnO into glasses, its structural and morphological characteristics were investigated after it was synthesized by solution combustion method. It was found that the inclusion of ZnO significantly impacted the glasses' density, molar volume, hardness, yield stress, and thermal stability. The optical properties of the produced glasses, such as transmittance, reflection, transparency, opacity and band gap energies, were examined and the effect of ZnO on the optical properties of the glasses was investigated. Crucially, the SZ glasses exhibited notable efficiency in shielding against gamma photons and fast neutrons. This is evidenced by the favourable change in the mass attenuation coefficients with increasing ZnO concentration. Parameters like the half-value layer, effective atomic number, and energy absorption buildup factors were calculated to gauge the radiation attenuation proficiency of the SZ glasses, demonstrating their potential utility in radiation protection. In conclusion, the developed SZ glasses display advantageous structural, thermal, and optical qualities, along with robust shielding capabilities against gamma photons and fast neutrons. This study contributes significant knowledge to the field of novel glass materials, paving the way for their application in various industrial and medical contexts requiring radiation shielding. [ABSTRACT FROM AUTHOR]

The distribution coefficient (Kd) of radionuclides is a crucial parameter in assessing the safety of high-level radioactive waste (HLW) geological repository. It is determined in the laboratory through batch and column experiments. However, differences in obtained Kd values from distinct experiments have not been thoroughly assessed and compared. This study evaluated strontium (Sr) sorption on different granite materials using static batch and dynamic experiments (column and core-flooding experiments). The results from batch sorption experiments showed higher Sr sorption on granite under acidic and strongly alkaline conditions, low solid–liquid ratios, and low ionic strength. In column experiments, a two-site sorption model was used to simulate Sr transport in crushed granite and mixed pure minerals. The sorption of Sr on crushed granite exhibited a higher affinity than that of mixed pure minerals. The dual-porosity transport model was employed to investigate Sr transport behavior in fractured granite in the core-flooding experiment. Kd obtained from batch sorption experiments are four to twenty times higher than those from column experiments, and two to three orders of magnitude higher than that from a core-flooding experiment. The results of this study provide valuable insights into safety assessment for the HLW geological repository. [ABSTRACT FROM AUTHOR]

Simple Summary: Otoliths, which are calcium carbonate structures found in the inner ears of fish, can be used to describe the use of freshwater and saltwater habitats during the lifespan of fish. This is performed by looking at the ratio of strontium to calcium along the radius of an otolith, where a high ratio indicates the use of saltwater and a low ratio indicates the use of freshwater. We studied brown trout (Salmo trutta L.) from the Swedish River Emån. We found that most brown trout, as expected, spent the first 1–2 years of their lives in freshwater before migrating to the Baltic Sea. We also found that 13% spent considerably less than one year in the river, which was not expected based on classical life history patterns for brown trout. In addition, we found that brown trout, which ranged from 3 to 6 years of age, returned to freshwater 2.3 times, and the amount of time spent in freshwater after hatching was negatively related to the number of visits to freshwater. Previous studies have explained that precocial migration occurs when there is a risk of drought. This explanation cannot apply to the permanently flowing River Emån. By analyzing otolith microchemistry, we examined the use of freshwater and marine environments by brown trout Salmo trutta L. that spawn in the Swedish River Emån and migrate to the Baltic Sea. We estimated the time juveniles spent in freshwater and the number of times the fish returned to freshwater, presumably to spawn. Twenty-six percent of the fish migrated to sea by 1 year of age. However, 13% spent less than one year in the river. Most brown trout (48%) migrated to the sea between 1 and 2 years of age. On average, brown trout, which averaged 4.4 years in age (range 3–6 years), returned to freshwater 2.3 times, and there was an inverse relationship between time spent in freshwater after hatching and the number of visits to freshwater. Our results do not support the classical life history pattern, where brown trout spend one or more years in freshwater before migrating to the sea. Here, we found evidence that part of the population leaves freshwater during their first year. While the cause for precocial migration in the River Emån is not known, our results from this permanently flowing river do not support the idea proposed for other Baltic Sea populations, where the risk of drought has been suggested to be the cause. [ABSTRACT FROM AUTHOR]

Polar discontinuities occur in oxide heterostructures due to varying net charges in the sub-unit cell layers. These polar discontinuities lead to structural reconstruction and often create diverse functionalities. This work constructs polar discontinuous in La0.67Sr0.33MnO3/SrCuO2 (LSMO/SCO) heterostructures on a (001)-orientated SrTiO3 (STO) substrate under different configurations. By changing the growth order of LSMO and SCO, we found two different compensating mechanisms for polar discontinuity. When LSMO is grown on SCO, interfacial polarity discontinuities result in the generation of a large number of oxygen vacancies within the LSMO film. Thus, the LSMO magnetism deteriorates. For the SCO/LSMO/SCO trilayer, the SCO capping layer can recover the LSMO magnetism. The scanning transmission electron microscope results show an atomic reconstruction at the SCO-on-LSMO interface and several oxygen vacancies at the SrO sublayer. The interface reconfiguration releases the polar energy, thereby inhibiting the generation of oxygen vacancies and improving the ferromagnetism of the LSMO film. Our work studies the impact of polar discontinuity at the interface, providing insights into the effects of interface polar discontinuities on functional materials. [ABSTRACT FROM AUTHOR]

The barium strontium orthosilicate [BaSr(1-x)SiO4:xSm3+] phosphors for various concentrations have been successfully prepared by using combustion synthesis approach. The synthesized samples have been characterized by using various techniques such as X-ray diffraction (XRD), photoluminescence spectroscopy, UV–Vis spectroscopy, high-resolutions tunneling electron microscopy (HRTEM) and scanning electron microscopy (SEM). By comparing the patterns obtained from XRD of the samples with the data from the JCPDS no. 00-154-0392 that was available, orthorhombic phase formation was verified. The images obtained by scanning electron microscopy (SEM) showed the porous nature of the phosphor. The HRTEM analysis confirmed the size of the particle of the nanophosphor. When the material is excited at a wavelength of 404 nm, the photoluminescence spectra of BaSrSiO4:Sm3+ demonstrate the presence of four distinct emission peaks, which may be attributed to the transitions from the 4G5/2 energy level to the 6HJ energy levels (where J takes on the values of 5/2, 7/2, 9/2 and 11/2). The hypothesis proposed by Dexter demonstrates that the phenomenon of concentration quenching between the Sm3+-Sm3+ ions present in the phosphors arises from the dipole–quadrupole interaction between them. Its deep reddish–orange emission is shown by the estimated Commission Internationale de I'Elcairage color coordinates, indicating its applicability in display enhancement and other optoelectronic applications. This study presents a comprehensive analysis of the luminescence characteristics of the synthesized phosphors, providing a full account of these features for the first time. [ABSTRACT FROM AUTHOR]

Acid deposition is widespread in Japan, but acidification of stream water is rare in forest ecosystems. Bedrock‐derived cations, including those released into the soil by weathering of bedrock minerals, generally act to neutralize acid deposition and flow out into streams. Volcanic ash, which is widespread in Japan, may also release cations and neutralize acids, but the contribution of volcanic‐ash‐derived cations is currently poorly explored. To assess the importance of volcanic ash as a source of base cations, we examined strontium in two catchments underlain by chert bedrock at Mount Amamaki, Japan. Additionally, we obtained comparative data from two sandstone‐bedrock catchments in the same area. We measured 87Sr/86Sr ratios in samples of stream water, bulk precipitation, riverbed rock, and soil from the catchments. We used the 87Sr/86Sr data to analyze the relative contributions of atmospheric deposition, bedrock, and volcanic ash in soil as sources of Sr in the stream waters. We estimated volcanic ash in soil to contribute between 46% and 78% of stream‐water Sr for one chert‐bedrock catchment, and between 0% and 52% for the other. We conclude that volcanic ash in soil is an important source of Sr in stream water. Thus, volcanic ash can act as a source of base cations and hence contribute to the acid‐neutralizing capacity of soil in forest ecosystems in Japan. [ABSTRACT FROM AUTHOR]

It is imperative to develop a comprehensive understanding of phase separation mechanisms in multi‐phase oxy‐fluoride glass ceramics (GCs) to customize their structural and optical characteristics for particular applications in photonics. The manuscript utilizes molecular dynamics (MD) simulations to examine the phase separation mechanisms in SiO2–Al2O3–SrF2–ZnF2–LnF3‐CrF3 (where Ln represents the lanthanide elements) GCs during the simultaneous precipitation of SrF2: Ln3+ and ZnAl2O4: Cr3+ nanocrystals. Insights into the atomic‐level interactions that regulate the separation and formation of distinct phases rich in fluoride and oxide are obtained through MD simulations. The results reveal that Sr2+ and Ln3+ ions partition preferentially into the fluoride phase, whereas Zn2+ and Cr3+ associate with the oxide aluminosilicate network. Remarkably, the separated fluoride and oxide phases bear structural similarities with the existing experimental outcomes. The introduction of SrF2 facilitates phase separation in oxy‐fluoride glass system by causing the formation of SrF2: Ln3+ nanocrystals in regions abundant in fluoride, while the substitution of ZnF2 for SrF2 results in the formation of ZnAl2O4: Cr3+ nanocrystals originating from the separated oxide phase. Therefore, the reported simulations offer molecular‐level insights into the mechanisms underlying phase separation and the functions of various glass components, thereby facilitating the development of customized oxy‐fluoride GCs with tailored properties. [ABSTRACT FROM AUTHOR]

We report the development of a compact, highly stable, monolithic-cavity, GaInP/AlGaInP-based vertical-external-cavity surface-emitting laser (VECSEL) with electronically tunable emission wavelength centered at 689.4425 nm for neutral strontium (Sr)-based applications. The output power reaches 40 mW (pump-power-limited) with ultra-low frequency and intensity noise performance resulting in a free-running linewidth of 720 Hz, reduced to 390 Hz when frequency locked to a reference cavity and verified via a heterodyne beat note measurement with 2 s averaging time. For shorter averaging times (0.1 ms), the free-running linewidth is as low as 40 Hz. We estimate a Lorentzian, or intrinsic, linewidth of 64 mHz from the frequency noise power spectral density at high frequencies, thus providing further evidence of the ultra-narrow fundamental linewidth of VECSELs. High frequency stability was measured via Allan deviation resulting in 1.05 × 10−12 at 2 s and 2.11 × 10−13 at 7 s averaging times when the 689 nm monolithic cavity VECSEL is free-running and locked, respectively, suitable for neutral Sr-based quantum technologies, such as optical clocks and atom interferometry. [ABSTRACT FROM AUTHOR]

Hygroscopic single crystals of a new hexagonal high‐temperature modification of Sr[ReO4]2 were prepared from a melt of Sr[ReO4]2 ⋅ H2O and SrCl2 ⋅ 6 H2O. The structure analysis of the obtained crystals by X‐ray diffraction revealed that the title compound crystallizes in the ThCd[MoO4]3‐type structure with the hexagonal space group P63/m and the lattice parameters a=1023.81(7) pm and c=646.92(4) pm (c/a=0.632) for Z=2 in its quenchable high‐temperature form. Two crystallographically independent Sr2+ cations are coordinated by oxygen atoms forming either octahedra or tricapped trigonal prisms, whereas the Re7+ cations are found in the centers of discrete tetrahedral meta‐perrhenate units [ReO4]−. Temperature‐dependent in‐situ PXRD studies of dry powder samples of Sr[ReO4]2 exhibited its thermal dimorphy with a phase‐transition temperature at 500–550 °C from literature‐known m‐Sr[ReO4]2 into the newly discovered h‐Sr[ReO4]2 (hexagonal). [ABSTRACT FROM AUTHOR]

Ocean acidification could modify the bioavailability and chemical properties of trace elements in seawater, which could affect their incorporation into the calcareous structures of marine organisms. Fish otoliths, biomineralized ear stones made by aragonite, are suspended within the endolymph fluid of teleosts, indicating that the elemental incorporation of otoliths might also be susceptible to ocean acidification. In this study, we evaluated the combined effects of CO2‐induced ocean acidification (pH 8.10, 7.70, and 7.30, corresponding to ocean acidification scenarios under the representative concentration pathway 8.5 model as projected by the Intergovernmental Panel on Climate Change) and water elemental concentrations of strontium (Sr) and barium (Ba; low, medium, and high) on elemental incorporation into otoliths of the flounder Paralichthys olivaceus at early life stages. Our results revealed that the elemental incorporation of Sr and Ba into otoliths was principally dependent on the corresponding water elemental concentrations rather than on ocean acidification. Moreover, the partition coefficients (DMe) of Sr and Ba may stabilize after dynamic equilibrium is reached as the water elemental concentration increases, but are not affected by ocean acidification. Therefore, the incorporation of Sr and Ba into otoliths of the flounder at early life stages may not serve as an effective indicator of ocean acidification. In other words, the findings suggest that ocean acidification does not impact the incorporation of Sr and Ba incorporation into otoliths when tracing the temperature or salinity experiences of the flounder. Our findings will provide new knowledge for understanding the potential ecological effects of ocean acidification on the recruitment dynamics of fish species. [ABSTRACT FROM AUTHOR]

Among natural radionuclides, 226Ra and 228Ra intake can contribute considerably to radiological dose. Liquid scintillation counting offers a reliable and sensitive method for measurement in environmental (water) and biological (urine) matrices. While the determination of 226Ra in water is quite simple, its determination in urine requires a suitable radiochemical procedure. In both cases an indirect measurement of daughter 222Rn (with 218Po and 214Po) in secular equilibrium allows to determine 226Ra activity. Moreover, in presence of anthropogenic radionuclides, a sequential separation of 228Ra and 90Sr in water has been developed, isolating daughters 228Ac and 90Y in secular equilibrium in the same vial. [ABSTRACT FROM AUTHOR]