Strontium Salts Research Articles

Enhancement in the Rate of CO2 Photoreduction Using Divalent Strontium Cation (Sr2+) Doped TiO2 Nanotube Arrays

The sunlight-assisted conversion of CO2 into portable value-added products has the potential to address both the energy and environmental challenges faced by the world. Therefore, we currently witness intense research activity and substantial progress in the field of CO2 photoreduction. Anatase TiO2 nanotube arrays (TNTAs) formed by electrochemical anodization constitute a well studied semiconductor photocatalyst with excellent optoelectronic properties and photocatalytic behavior [1, 2]. Yet, many aspects related to structure, surface composition, adsorbates, reaction intermediates, rate of reaction, multi-step electron transfer steps, etc. remain poorly understood even for TiO2. This led to our interest in forming surface coatings and bulk nanocomposites of TNTAs with metal oxides of Sr, Mg, Ca, Zn etc, which provide basic sites on the surface of the catalyst for the chemisorption of CO2 molecules. The higher basicity of hydroxyl groups associated with alkaline earth metals generate carbonate and bicarbonate adsorbates which enhance the reactivity of CO2 [3]. Divalent metal cations are also known to influence and modify the crystallographic texture of TiO2 during the annealing treatment step at elevated temperature [4].Here we performed divalent strontium cation (Sr2+) doping of anodically grown TNTAs using two different techniques – an electrochemical cathodic treatment in Sr2+-containing electrolytes and a wet impregnation technique using an aqueoussolution of strontium salts. The X-ray diffraction pattern and Raman spectra indicate the formation of Sr compounds at the TNTA surface. Sr-doping results in modification of the crystallographic texture of anatase phase TNTAs, increased lattice strain, reduced crystal size, and phonon confinement. Subtle changes are observed in the infrared spectra of the CO2 adsorbed on the Sr-doped TNTAs specifying a larger prevalence of monodentate and bidentate carbonate species on the surface. This attributes to the higher alkalinity of surface hydroxyls bound to Sr in comparison to the Ti-bound hydroxyls. In addition to linearly adsorbed CO2, a smaller population of bent CO2 molecules on the surface is observed, which suggests an enhanced stabilization of the carbon dioxide anion radical on the Sr-doped TNTA surfaces. Finally, under AM1.5G one sun illumination, the cathodized TNTAs produce 25 µmolg-1hr-1 whilethe wet impregnated Sr-doped TNTAs produce 17 µmolg-1hr-1 of CO which are nearly 3 and 2 times the amount of CO generated by bare TNTAs (7.7 µmolg-1hr-1) respectively.REFERENCES: Vahidzadeh, Ehsan, et al. "Asymmetric multipole plasmon-mediated catalysis shifts the product selectivity of CO2 photoreduction toward C2+ products." ACS Applied Materials & Interfaces13.6 (2021): 7248-7258.Zeng, Sheng, et al. "Optical control of selectivity of high rate CO2 photoreduction via interband-or hot electron Z-scheme reaction pathways in Au-TiO2 plasmonic photonic crystal photocatalyst." Applied Catalysis B: Environmental267 (2020): 118644.Kwon, Stephanie, et al. "Alkaline-earth metal-oxide overlayers on TiO 2: application toward CO 2 photoreduction." Catalysis Science & Technology6.21 (2016): 7885-7895.Kisslinger, Ryan, et al. "Preferentially oriented TiO2 nanotube arrays on non-native substrates and their improved performance as electron transporting layer in halide perovskite solar cells." Nanotechnology30.20 (2019): 204003.

Effect of gallium and strontium salts on the characteristics and biological applications of Sr and Ga-modified titanate nanotubes

In this work, we report the synthesis of Na-TiNTs sodium titanate nanotubes prepared by the hydrothermal method in a highly alkaline subsequently modified by the substitution of Na+ ions present in the walls of the nanotubes by ions of Sr2+ and Ga3+ revealing the presence of phases such as SrOH2 and α-GaOOH through the analysis by X-ray diffraction. Raman spectroscopy showed the characteristic peaks of the vibrational modes of the titanate nanotube structure. UV–Vis analysis revealed a blueshift of absorption edge that leads to an increase in the bandgap with the insertion of Sr and Ga ions. The ion exchange causes a decrease in the Urbach energy, which suggests a certain attenuation in the concentration of structural defects.Through the SEM images it is observed the cluster of interwoven nanotubes it self is characteristic of titanate nanotubes and, the elemental mapping shows the complete efficiency of the reaction process of sodium ion exchange by strontium and gallium in the Sr-TiNT and Ga-TiNT samples respectively, showing the environment of the chemical composition of the surface with the presence of chemical elements such as Sr, Ga. The Na-TiNT, Sr-TiNT, and Ga-TiNT nanotubes did not show direct antibacterial activity against the tested strains. The Na, Ga, and Sr TiNTs of the ampicillin antibiotic exhibited significant values against the microorganism S. aureus 10 compared to the control antibiotic, thereby reducing its inhibitory concentration. The same was observed for gentamicin. The Na-TiNT, in combination with gentamicin, displayed a reduction in inhibitory concentration compared to the control for P. aeruginosa 24. In E. coli 06, the Na, Sr, and Ga TiNTs showed a reduction in concentration when combined with gentamicin, indicating a potential synergistic effect.

Access to Green Pyrotechnic Compositions via Constructing Coordination Polymers: A New Approach to the Application of 3,4-Dinitropyrazole.

Alkali and alkaline-earth metal salts with 3,4-dinitropyrazole (DNP) were synthesized by the reaction of DNP with stoichiometric amounts of the corresponding metal hydroxide-, oxide-, or carbonate-based highly pure salts, and products were fully characterized. Determination of single-crystal structures of all new complexes except for the lithium and strontium salts was performed by X-ray diffraction techniques. The cesium salt crystallized no water among them. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) manifested that these salts have satisfactory thermal stabilities with decomposition temperatures above 210 °C. They also showed that there exists strong bonding of crystallized water among lattices, which disappeared at temperatures equal to or above 115 °C except for salts MES-3, MES-4, and MES-9. In addition, the percentage of water contents was confirmed by using DSC and TGA methods. The constant-volume combustion heats of these metal salts containing DNP anions were measured using an oxygen bomb calorimeter due to their expectant interest in energetic materials, and their standard molar formation enthalpies were obtained. The investigated salts were found to be insensitive toward friction and impact. Findings of burning tests performed with experimental formulations using MES-1, MES-7, MES-8, and MES-9 certify that these four salts might be more promising candidates for application in green pyrotechnics.

Phosphogypsum conversion under conditions of SC-CO2

This article looks into process of supercritical-CO2 phosphogypsum (PG) conversion, which is production residue after making mineral fertilizers by "Kasphosphate" LLC. Nowadays, over 30 million tons of PG have been accumulated in Kazakhstan; its background radiation is low enough to recycle it into valuables such as construction materials, rare earth elements and strontium salts. Complete factorial experiment method was used to describe conversion process; conversion of PG into CaCO3 was optimized using simplex method. Conversion optimization outcomes show possibility of using fewer reagents and shortening conversion process compared to existing technologies. Conversion degree is 87% after 10 min at 33 °С. Conversion was carried out at semi-industrial supercritical equipment with maximum CO2 flow rate up to 5000 g/min and integrated CO2 recirculation system. Characteristics of initial PG samples and conversion products/semi-products were done using X-ray phase analysis, scanning electron microscopy, atomic absorption spectroscopy, ICP-MS, and gravimetric procedure. In order to obtain purer CaCO3 PG was cleared of water-soluble impurities beforehand. As conversion result, finely dispersed CaCO3 and Ca(HCO3)2 as well as Na2SO4 solution were obtained.

Titanium Superoxide for the Oxidation of Amines: Synthesis of bis(3‐nitro‐1H‐1,2,4‐triazol‐5‐yl)methane and its Metal Salts

AbstractBis(3‐nitro‐1H‐1,2,4‐triazol‐5‐yl)methane (BNTM) was synthesized in 79 % yield via the oxidation of 5,5'‐diamino‐3,3’‐methylene‐1H‐1,2,4‐triazole (DABTM) with titanium superoxide in a water and hydrogen peroxide solution. BNTM synthesized by this method was characterized via low‐resolution mass spectrometry (LRMS), nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), elemental analysis, and single crystal X‐ray crystallography for comparison with BNTM produced by traditional routes. The cesium, lithium, potassium, rubidium, sodium, and strontium salts of BNTM were characterized for their thermal stabilities and mechanical sensitives. Each of the salts possessed multiple hydrates, the loss of the associated water can clearly be seen by thermal gravimetric analysis (TGA). All the salts were less sensitive to impact than neutral BNTM and, except for the sodium and cesium salts, were less sensitive to friction. Single crystal X‐ray crystallography was utilized to analyze the crystal structures obtained for the cesium, strontium, and sodium salts.

Совместная трансмутация стабильных изотопов Cs и Sr в микробиологических системах и перспективы ускоренной деактивации жидких радиоактивных отходов

It was found during the research that in the experimental and control bioreactors, which at the beginning of the experiments contained only cesium and strontium, by the end of the experiments, yttrium and barium were found. These isotopes are formed as a result of low-energy nuclear reactions involving protons. In addition, in experimental bioreactors with an optimal composition, a two to threefold increase in the concentration of yttrium was recorded in comparison with the control non-optimal experiments. Accumulation of strontium and cesium in biomass was registered, which is explained by the process of biosorption. It is known that biosorption is the first step towards nuclear transformation (biotransmutation). At the same time, one of the main conditions for the nuclear transformation of biomass elements is its maximum efficient growth. An unexpected fact discovered during the experiment is that yttrium and barium were also found in the control bioreactor, where no biomass was added before the experiment, but only deionized water, glucose, and the initial stable cesium and strontium salts. It is important to note that these elements were not detected in the analysis of the initial salts, substrates, and deionized water. Most likely, the presence of yttrium and barium is due to inoculation of the control fluid of the bioreactor (where no biomass pellets were added) with microorganisms from the experimental bioreactors during their periodic opening for taking current pH samples and adding glucose. Also, the work recorded a decrease in the content of cesium and strontium in the liquid by 20% and 55%, respectively, which goes beyond the statistical error.

Sol-Gel Combustion Synthesis, Crystal Structure and Luminescence of Cr3+ and Mn4+ Ions in Nanocrystalline SrAl4O7

A series of strontium dialuminate SrAl4O7 nanopowders with the grossite-type structure doped with chromium and manganese ions were synthesized by the combined sol–gel solution combustion method with use of two different strontium salts. The Cr3+ and Mn4+ ions concentrations were varied from 0.05 to 5 at.%. Evolution of phase composition, crystal structure, and microstructural parameters of the nanocrystalline materials depending on the synthesis conditions, temperature of thermal treatment, and dopant content were investigated by the X-ray powder diffraction and the scanning electron microscopy techniques. Photoluminescent properties of SrAl4O7 nanophosphors activated with Cr3+ and Mn4+ ions were studied at room temperature. The samples exhibit typical photoluminescence in the deep-red spectral region, corresponding to d-d transitions in Cr3+ or Mn4+ ions. The intensity of this deep-red emission is dependent on the dopant concentration and annealing temperature. Features of the formation of octahedral surroundings around Cr3+ or Mn4+ ions are discussed.

Strontium Binding to α-Parvalbumin, a Canonical Calcium-Binding Protein of the “EF-Hand” Family

Strontium salts are used for treatment of osteoporosis and bone cancer, but their impact on calcium-mediated physiological processes remains obscure. To explore Sr2+ interference with Ca2+ binding to proteins of the EF-hand family, we studied Sr2+/Ca2+ interaction with a canonical EF-hand protein, α-parvalbumin (α-PA). Evaluation of the equilibrium metal association constants for the active Ca2+ binding sites of recombinant human α-PA (‘CD’ and ‘EF’ sites) from fluorimetric titration experiments and isothermal titration calorimetry data gave 4 × 109 M−1 and 4 × 109 M−1 for Ca2+, and 2 × 107 M−1 and 2 × 106 M−1 for Sr2+. Inactivation of the EF site by homologous substitution of the Ca2+-coordinating Glu in position 12 of the EF-loop by Gln decreased Ca2+/Sr2+ affinity of the protein by an order of magnitude, whereas the analogous inactivation of the CD site induced much deeper suppression of the Ca2+/Sr2+ affinity. These results suggest that Sr2+ and Ca2+ bind to CD/EF sites of α-PA and the Ca2+/Sr2+ binding are sequential processes with the CD site being occupied first. Spectrofluorimetric Sr2+ titration of the Ca2+-loaded α-PA revealed presence of secondary Sr2+ binding site(s) with an apparent equilibrium association constant of 4 × 105 M−1. Fourier-transform infrared spectroscopy data evidence that Ca2+/Sr2+-loaded forms of α-PA exhibit similar states of their COO− groups. Near-UV circular dichroism (CD) data show that Ca2+/Sr2+ binding to α-PA induce similar changes in symmetry of microenvironment of its Phe residues. Far-UV CD experiments reveal that Ca2+/Sr2+ binding are accompanied by nearly identical changes in secondary structure of α-PA. Meanwhile, scanning calorimetry measurements show markedly lower Sr2+-induced increase in stability of tertiary structure of α-PA, compared to the Ca2+-induced effect. Theoretical modeling using Density Functional Theory computations with Polarizable Continuum Model calculations confirms that Ca2+-binding sites of α-PA are well protected against exchange of Ca2+ for Sr2+ regardless of coordination number of Sr2+, solvent exposure or rigidity of sites. The latter appears to be a key determinant of the Ca2+/Sr2+ selectivity. Overall, despite lowered affinity of α-PA to Sr2+, the latter competes with Ca2+ for the same EF-hands and induces similar structural rearrangements. The presence of a secondary Sr2+ binding site(s) could be a factor contributing to Sr2+ impact on the functional activity of proteins.

Structure, Optical, and Photoelectric Properties of Lead-Sulfide Films Doped with Strontium and Barium

Evolution of the morphology, composition, structural characteristics (lattice constant, microstrains, texturing), and optical and photoelectric properties of PbS films produced by chemical bath deposition in the presence of ammonium iodide and strontium or barium chlorides at a concentration up to 5 mM is studied. According to the data of energy dispersive X-ray analysis, the content of strontium in the PbS films is 0.4–0.7 at %, whereas the content of barium is beyond the determination error. The size of the particles forming the films varies from ~200 to ~400 nm, and the size distribution of the particles is monomodal. The introduction of NH4I and SrCl2 or BaCl2 into the reactor retains the B1 cubic structure of lead sulfide, but gives rise to an unsteady change in the lattice parameter, which is due to the creation of vacancy-type or interstitial ion defects. The introduction of salts of strontium or barium does not influence the band gap, but changes the intensities of the impurity absorption bands deep in the band gap or near the bottom of the conduction band. The dependences of the volt–watt sensitivity of the films on the content of salts of strontium and barium are of an extreme character and show maxima at 0.05 and 0.1 mM, respectively.

Synthesis and Photoluminescence study of Strontium salts with 2-Methyl-8-Hydroxyquinoline and 8-Hydroxyquinoline

The pure green and turquoise green-emitting organometallic complex of strontium(II) with 8-Hydroxyquinoline and 2-methyl-8-hydroxyquinoline were synthesized by using Co-precipitation method. The structure of Sr(8-Hq)2 and Sr(2-Me-8Hq)2 was studied with Fourier transform infrared spectroscopy, and the vibrational peak of the Sr-O bond was found at 503 cm−1 and 499 cm−1 respectively. The X-Ray diffraction spectra are taken and compared with XRD data of raw materials to confirm the formation of the complex. Further UV-Absorption was studied, and the optical band gap is 2.813eV and 2.852eV, respectively, by using Taucs plot method. The photoluminescent study carried out in solution medium, and the emission wavelength found at 526nm and 509nm, and the color is confirmed using the CIE plot method, and the emission color is pure green and turquoise green. The complex may have significant applications as emitters in organic optoelectronic devices.

Solid−liquid phase equilibria of the quinary system containing lithium, sodium, calcium, strontium and chloride ions at 273.15 K and 101.325 kPa

The solid–liquid phase equilibria of systems LiCl–NaCl–CaCl2–SrCl2–H2O and CaCl2–SrCl2–H2O at 273.15 K and 0.1 MPa were investigated with the isothermal equilibrium method. The solid–liquid equilibrium phase diagrams were constructed with the experimental solubilities. The phase diagram in the ternary system consists of one univariant solubility curve saturated with solid solution (Ca,Sr)Cl2·6H2O, and one crystallization field of the solid solution. There are three invariant points, seven isothermal univariant curves, and five crystallization regions saturated with NaCl corresponding to (Ca,Sr)Cl2·6H2O, SrCl2·2H2O, LiCl·2H2O, CaCl2·4H2O and LiCl·CaCl2·5H2O in the dry-salt diagram of the quinary system. The areas of crystallization zones decrease according to the above order. The J(NaCl), J(H2O), refractive index and density of the solution gradually change regularly with the increasing of J(CaCl2) in the solution. These results on phase diagrams of the quinary system can supply theoretical reference for lithium salts and strontium salts separation from calcium chloride type brine.

Determining elemental strontium distribution in rat bones treated with strontium ranelate and strontium citrate using 2D micro‐XRF and 3D dual energy K‐edge subtraction synchrotron imaging

Strontium‐based medications, such as strontium ranelate, have been suggested to have therapeutic effects in patients with osteoporosis. Strontium salts available off‐shelf in stores across North America are assumed to provide similar effects as strontium ranelate and thus should lead to similar distributions of elemental strontium incorporated in bone. The objective of this study was to compare the spatial distribution of strontium in animal bones following the administration of strontium ranelate and strontium citrate. Seventeen‐week‐old Sprague–Dawley rats were split into three groups over 10 weeks and given 625 mg/kg/day of strontium ranelate and 676 mg/kg/day of strontium citrate; the control group received no additional supplementary strontium. The humeri were collected from all animals, and strontium distribution was mapped using 2D micro‐XRF and 3D dual energy K‐edge subtraction (KES) imaging. 2D and 3D elemental mapping methods demonstrated that strontium delivered during treatment by both salts had the same spatial distribution. 3D elemental strontium maps of treated animal bones showed that strontium was largely observed in the trabecular regions under the epiphyseal (growth) plate. The thickness of the strontium layers in both the strontium ranelate and strontium citrate sample was not significantly different (p = .9201). 2D micro‐XRF and 3D dual‐energy KES images effectively elucidated the spatial distribution of elemental strontium in calcified tissue. These methods provide a novel approach to evaluating the potential efficacy of strontium supplements in the treatment of osteoporosis.

Designing Novel Multiferroic Perovskite Oxide for Prospective Photovoltaic Applications

Multiferroics, with two or more coexisting ferroic orders (ferroelectric, ferro (antiferro)-magnetic) in a single phase, display promising photovoltaic characteristics which can be utilised in solar energy harvesting. However, the efficacy is seriously challenged due to their wide band gap, far from the ideal value of ~1.52 eV for photovoltaic applications, resulting in overall unimpressive performance. In the present work, an approach towards imparting multiferroism in an otherwise non-ferroic system was adopted through strain engineering. Bulk SrMnO3 (SMO) is antiferromagnetic-paraelectric. However, our previous first-principles studies predicted high-pressure phase transformation from bulk non-polar phase to a tetragonal polar phase. In light of the above, SMO was synthesised hydrothermally at 200°C for 96 h using water-soluble nitrate salts of strontium and manganese. FESEM study reveals the formation of hexagonal bipyramid shaped SMO crystals with elongated 1-D features. Powder x-ray diffraction studies and subsequent Rietveld refinement confirm the presence of hexagonal (P63/mmc) as well as tetragonal (P4mm) phases. Energy dispersive x-ray analysis (EDAX) confirms Sr/Mn ≈ 1, the stoichiometric ratio. UV-VIS spectroscopy was utilised to estimate the optical bandgap of the as-grown sample which was found to be in the range of 1.4-1.5 eV. Temperature-dependent magnetisation plot indicates the magnetic transition temperature, ~275K.

Alternative pathways to α,β-unsaturated ketones via direct oxidative coupling transformation using Sr-doped LaCoO3 perovskite catalyst.

A strontium-doped lanthanum cobaltite perovskite material was prepared, and used as a recyclable and effective heterogeneous catalyst for the direct oxidative coupling of alkenes with aromatic aldehydes to produce α,β-unsaturated ketones. The reaction afforded high yields in the presence of di-tert-butylperoxide as oxidant. Single oxides or salts of strontium, lanthanum and cobalt, and the undoped perovskite offered a lower catalytic activity than the strontium-doped perovskite. Benzaldehyde could be replaced by benzyl alcohol, dibenzyl ether, 2-oxo-2-phenylacetaldehyde, 2-bromoacetophenone or (dimethoxymethyl) benzene in the oxidative coupling reaction with alkenes. To our best knowledge, reactions between these starting materials with alkenes are new and unknown in the literature.

Використання наночасток гідроксилапатиту стронцію для профілактики та лікування підвищеної стертості зубів (лабораторні дослідження)

Summary. The paper describes a method for strontium hydroxyapatite nanoparticles for the prevention and treatment of high abrasion of teeth with minimum size of the primary particles with a high degree of aggregation and the penetration of nanoparticles into the crystal lattice of the tooth enamel, which is provided by increasing the density of the enamel layer the effectiveness of treatment and prevention of high abrasion of teeth.The aim of the study – development of several derivatives of strontium salts having different structure of nanoparticles for the purpose of their further integration into the enamel layer to increase the enamel strength.Materials and Methods. On the basis of the proposed method we designed research protocol samples of teeth with increased abrasion to assess the penetration and fixation of nanoparticles on the surface of the tooth enamel. The use of the proposed method in a dental practice would improve the effectiveness of treatment and prevention of high abrasion of teeth due to inclusion in the complex treatment in the form of applications, ointments and gels.Results and Discussion. We obtained nanoparticles synthesized from strontium nitrate in the form of prisms measuring from 30 nm to 34 nm in size obtained by precipitation from strontium chloride.Conclusions. As a result of experimental research, strontium hydroxylapatite nanostructures from anion derivatives (chloride, nitrate, acetate) were discovered. Microscopic investigation showed that they consisted of plates, needles and equiaxed particles with dimensions from 19.4 to 35 nm, which is confirmed by X-ray, trace studies and microscopic studies.

Evidence for Indirect Action of Ionizing Radiation in 18-Crown-6 Complexes with Halogenous Salts of Strontium: Simulation of Radiation-Induced Transformations in Ionic Liquid/Crown Ether Compositions.

Ionic liquid/crown ether compositions are an attractive alternative to traditional extractants in the processes for spent nuclear fuel and liquid radioactive wastes reprocessing. These compositions are exposed to ionizing radiation, and their radiation stability, especially in the presence of metal salts, is a crucial issue. In the present study, the macrocyclic 18C6·Sr(BF4)2 and 18C6·Sr(PF6)2 complexes simulating the components of metal loaded ionic liquid/crown ether extractants were synthesized and their structures were characterized by FTIR spectroscopy and single-crystal X-ray diffraction analysis. Inclusion of Sr2+ cation into the 18C6 cavity resulted in more symmetric D3d conformations of the macrocycle. The structural transformations of the crown ether were accompanied by an elongation of polyether C-O bonds that could increase the possibility of radiolytic cleavage of the macrocycle. However, EPR study of the synthesized compounds subjected to X-ray irradiation revealed predominant formation of macrocyclic -CH2-ĊH-O- radicals. This result demonstrated an evidence for indirect action of ionizing radiation on individual components of the complexes and was reasonably described by a positive "hole" transfer from primary macrocyclic radical cation to fluorous anion at the primary stages of radiolysis and a subsequent interaction of fluorine atom with 18C6 macrocycle in secondary radical reactions. The observed effects may be partially responsible for enhanced sensitivity of the ionic liquid/crown ether extractants to ionizing radiation due to chemical blocking of the crown ether with radiolytic HF, radiation-chemical degradation of the 18C6, and precipitation of a low-soluble SrF2.

Synthesis and improved photoluminescence of a novel red phosphor LiSrGaF6:Mn4+ for applications in warm WLEDs.

Red phosphors composed of Mn4+-activated complex fluorides have attracted considerable attention for applications in warm white light-emitting diodes (WLEDs). In the present study, we report a facile strategy to synthesize a novel red phosphor LiSrGaF6:Mn4+ (LSGF:Mn) at room temperature, and we also discuss its formation mechanism. Mn4+ ions occupy Ga3+ sites located at the centers of distorted [GaF6]3- octahedrons and emit intense red luminescence when excited by UV or blue light. The effects of synthesis conditions such as the type of strontium salts, the concentrations of K2MnF6 and NH3·H2O, and the reaction temperature have been investigated. The luminescence intensity of the phosphor LSGF:Mn has been improved by optimizing the synthetic parameters. The as-prepared phosphor LSGF:Mn exhibits broad and intense absorption in the blue region and bright luminescence in the red region, which indicate that it is promising for applications in warm WLEDs.

The effects of mometasone furoate and strontium chloride in a rat model of allergic rhinitis.

Neurogenic inflammation plays a role in the pathophysiology of allergic rhinitis. Highly effective in reducing the sensory irritation caused by some substances, strontium salts directly affect C-type nerve fibers. The aim of this study was to compare the efficacy of mometasone furoate and strontium chloride on early-phase symptoms in a rat model of allergic rhinitis. Wistar albino rats (n = 24) were randomly divided into three groups: the mometasone group, receiving 1 μg mometasone furoate (2 µl/site); the strontium 3% group, receiving 3% strontium chloride (2 μl/site); and the strontium 5% group, receiving 5% strontium chloride (2 μl/site). To induce significant nasal symptoms of allergic rhinitis, 5 µmol of histamine dihydrochloride (HDC) (2 µl/site) was administered. Symptoms of allergic rhinitis were recorded as frequencies of sneezing and nasal rubbing during a 15-minute interval. On days 1 and 2, respectively, 0.9% sodium chloride (NaCl) (2 μl/site to each nasal cavity) and HDC were administered in all of the study groups. On days 3 and 4, the study drugs were administered 10 and 30 minutes before the administration of HDC. On day 5, the study drugs were administered 10 minutes after the administration of HDC. The results of the present study revealed that when strontium chloride or mometasone furoate was administered 30 minutes before the onset of symptoms, a significant decrease was observed in sneezing and nasal rubbing. The number of sneezing occurrences was significantly lower and the number of nasal rubbing occurrences was higher in the strontium 3% group compared to the groups in which mometasone furoate and 5% strontium chloride were administered after onset of symptoms. Recent studies have investigated the efficacy and safety of strontium chloride nasal drops compared with common pharmacologic treatments of allergic rhinitis. These studies have revealed that allergic rhinitis can be successfully and safely treated with strontium-chloride-containing products, thus offering a potential new treatment strategy.

The reduction in inflammation and impairment in wound healing by using strontium chloride hexahydrate

Background: Numerous growth factors, cytokine, mitogen and chemotactic factors are involved in wound healing. Even though inflammation is important for the stimulation of proliferative phase, excessive inflammation also causes impairment in wound healing. Strontium salts suppress keratinocyte-induced TNF-alpha and interleukin-1 and interleukin-6 in in vitro cultures. This study was conducted to determine the effects of administration of topical strontium chloride hexahydrate on wound healing through TNF-alpha and TGF-beta in surgical wound healing model of in-vivo rat skin.Material and methods: Twenty-four rats were used in the study. After approximately 2 cm cutaneous–subcutaneous incision was horizontally carried out on the mid-neckline of the rats, the incision was again closed using 2.0 vicryl. The rats were assigned into three groups including eight rats in each group. Placebo emollient ointment and also the ointments, which were containing 5% and 10% strontium chloride hexahydrate and were prepared at the same base with placebo ointment, were administered to the groups by a blind executor twice a day for a week. At the end of seventh day, the rats were sacrificed and cutaneous and subcutaneous tissue of their wound site was resected for histopathological examination. Scoring of histopathological wound healing and scoring of tissue TNF-alpha and TGF-beta level with immunohistochemical staining were performed.Results: The groups, to which both 5% and 10% strontium chloride hexahydrate was administered, had lower immunohistochemical TNF-alpha levels and histopathological wound scores compared to controls, which was statistically significant (p < 0.05).Conclusion: Strontium chloride hexahydrate can lead to impairment in wound healing by suppressing inflammation through TNF-alpha.

Strontium chloride hexahydrate as a candidate molecule for long-term treatment of allergic rhinitis.

Background & objectives:Neurogenic inflammation plays a role in the pathophysiology of allergic rhinitis (AR). Strontium salts are highly effective in reducing the sensory irritation. This study was aimed to investigate the efficacy of strontium chloride (SC) on AR symptoms based on the duration of SC use before the symptoms begin.Methods:Wistar albino rats (n=18) were randomly divided into three groups: Group 1, received 1μg mometasone furoate (MF); Group 2, three per cent SC; and Group 3 received five per cent SC (2 μl/site). Drugs were administered to the each nasal cavity for three weeks every morning. On the days 7, 14 and 21, histamine dihydrochloride (HD) 5 μmol (2 μl/site) was administered and the frequencies of nasal rubbing and sneezing were counted for 15 min.Results:After 7, 14 and 21 day medication period, the groups were compared in terms of the frequency of sneezing and nasal rubbing following HD. There was a significant difference among the groups in terms of the frequency of sneezing on the day 7 (P< 0.05). Intragroup comparisons for the nasal rubbing showed significance (P< 0.05). In Group 3, there was a decrease in the number of nasal rubbings on the day 14 and 21; however, the difference was not significant.Interpretation & conclusions:Our results showed that three and five per cent SC were less effective than MF for sneezing during the first week, but the efficiency was equal to that of MF after the first 14 days. Long-term use of SC was as effective as MF on nasal rubbing. SC can be as effective as MF on both sneezing and nasal rubbing on regular use over three weeks.