Lanthanum Strontium Manganese Research Articles

Assessment of Bulk Oxygen Capacity and Transient Redox Behavior of Foamed Lanthanum Strontium Manganese Perovskites

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

Redox Performance and Optimization of the Chemical Composition of Lanthanum–Strontium–Manganese-Based Perovskite Oxide for Two-Step Thermochemical CO2 Splitting

The effects of substitution at the A- and B sites on the redox performance of a series of lanthanum–strontium–manganese (LSM)-based perovskite oxides (Z = Ni, Co, and Mg) were studied for application in a two-step thermochemical CO2 splitting cycle to produce liquid fuel from synthesis gas using concentrated solar radiation as the proposed energy source and CO2 recovered from the atmosphere as the prospective chemical source. The redox reactivity, stoichiometry of oxygen/CO production, and optimum chemical composition of Ni-, Co-, and Mg-substituted LSM perovskites were investigated to enhance oxygen/CO productivity. Furthermore, the long-term thermal stabilities and thermochemical repeatabilities of the oxides were evaluated and compared with previous data. The valence changes in the constituent ionic species of the perovskite oxides were studied and evaluated by X-ray photoelectron spectroscopy (XPS) for each step of the thermochemical cycle. From the perspectives of high redox reactivity, stoichiometric oxygen/CO production, and thermally stable repeatability in long-term thermochemical cycling, Ni0.20-, Co0.35-, and Mg0.125-substituted La0.7Sr0.3Mn perovskite oxides are the most promising materials among the LSM perovskite oxides for two-step thermochemical CO2 splitting, showing CO productivities of 387–533 μmol/g and time-averaged CO productivities of 12.9–18.0 μmol/(min·g) compared with those of LSM perovskites reported in the literature.

Study of protein encapsulated manganite nanoparticles for magnetic Hyperthermia

Used in the past as an efficient drug-delivery carrier, the natural protein Bovine Serum Albumin (BSA) has been tried in the present study to coat Lanthanum Strontium Manganese Oxide (LSMO) nanoparticles (NPs) called manganite, for magnetic Hyperthermia applications. LSMO NPs generate heat when subjected to a radiofrequency magnetic field and as a novel attempt; they were functionalized with BSA by its “denaturation” at 80°C. This was done to probe the effect of protein bonding with nanoparticles by “unfold” of its molecular structure and to enhance the biocompatibility of LSMO. Presence of BSA on NPs was assessed through electron microscopy (HRTEM), Fourier transform (IR) spectroscopy and thermogravimetric analysis (TGA); that showed successful outcomes. The magnetization was analyzed by super quantum interface device (SQUID). For Hyperthermia studies, BSA coated NPs were dispersed in phosphate buffer saline and attained an appreciable specific absorption rate of 126.9 W/g showing their potential for future applications.

Three-dimensional numerical simulation of oxygen isotope transport in lanthanum strontium manganese - Yttria-stabilized zirconia cathode of solid oxide fuel cell

Distribution of oxygen isotope 18O concentration which was labeled in lanthanum strontium manganese (LSM) – yttria-stabilized zirconia (YSZ) cathode of a solid oxide fuel cell (SOFC) is predicted through numerical simulations using a three-dimensional microstructure which was reconstructed by a focused ion beam-scanning electron microscopy (FIB-SEM). The electrochemical reaction under the SOFC operation is first numerically simulated, then the unsteady 18O transport is simulated by coupling self-diffusion by concentration gradient, migration by the electrochemical potential field, and electrochemical reaction at the triple phase boundaries. Predicted results were compared with the measured 18O concentration by a secondary ion mass spectrometry taken at the intermediate plane of the reconstructed 3D microstructure, which showed qualitative consistency between them. Thus, from the direct correlation of the electrochemical reaction and 18O concentration in an actual electrode microstructure, influence of electrochemical reaction was discussed. The present approach provides useful information for the interpretation of the oxygen labeling experiment results, which can cultivate better understanding of the electrochemical reaction mechanism in the SOFC electrodes.

Effect of Sr-Doping on Structural and Magnetic Properties of La1−xSrxMnO3 Nanoparticles

Polycrystalline La[Formula: see text]SrxMnO3 ([Formula: see text]–0.4) lanthanum strontium manganese oxide (LSMO), nanoparticles exhibit interesting size-dependent structural and magnetic properties. LSMO nanoparticles have attracted considerable attention in recent years because of their tunable magnetic properties like intrinsic and extrinsic colossal magnetoresistance, single domain superparamagnetic structure with near room temperature Curie point ([Formula: see text]). They find interesting applications in catalysis, biomedicine and data storage. Properties of LSMO nanoparticles are strongly correlated to extent of Sr-doping at La-site, their particle size and the extent to which different crystallographic phases (rhombohedral/orthorhombic) appear. A major aim of this study is to understand the effect of Sr-doping on the structural and magnetic properties of LSMO nanoparticles synthesized via the sol–gel auto combustion route. Structural and magnetic properties were investigated by powder X-ray diffraction coupled with Rietveld refinement and vibrating sample magnetometer, respectively. Rietveld refinement of diffractograms revealed that irrespective of Sr-doping, LSMO nanoparticles were crystallized in rhombohedral ([Formula: see text]) and orthorhombic (Pbnm) mixed phases. The rhombohedral phase appears to be the dominant crystallographic phase. VSM study revealed that irrespective of Sr-doping LSMO nanoparticles exhibit soft ferromagnetic behavior. With the increase in Sr-doping, saturation magnetization ([Formula: see text]) of LSMO nanoparticles increases, while their Curie temperature remains constant at [Formula: see text][Formula: see text]K. To establish the correlation between structural and magnetic properties of LSMO nanoparticles, [Formula: see text]–[Formula: see text] curves were fitted with modified Langevin function. It was observed that with an increase in Sr-doping, magnetic domain size, polydispersity and saturation magnetization increase. This increase is attributed to the corresponding increase in the rhombohedral phase fraction of LSMO nanoparticles. Thus, through Sr-doping, the magnetic properties of LSMO nanoparticles can be tuned by controlling their crystallographic phase fractions.

Hyperthermia and doxorubicin release by Fol-LSMO nanoparticles induce apoptosis and autophagy in breast cancer cells.

Background: Studies on the anticancer effects of lanthanum strontium manganese oxide (LSMO) nanoparticles (NPs)-mediated hyperthermia at cellular and molecular levels are scarce. Materials & methods: LSMO NPs conjugated with folic acid (Fol-LSMO NPs) were synthesized, followed by doxorubicin-loading (DoxFol-LSMO NPs), and their effects on breast cancer cells were investigated. Results: Hyperthermia (45°C) and combination treatments exhibited the highest (∼95%) anticancer activity with increased oxidative stress. The involvement of intrinsic mitochondria-mediated apoptotic pathway and induction of autophagy was noted. Cellular and molecular evidence confirmed the crosstalk between apoptosis and autophagy, involving Beclin1, Bcl2 and Caspase-3 genes with free reactive oxygen species presence. Conclusion: The study confirmed hyperthermia and doxorubicin release by Fol-LSMO NPs induces apoptosis and autophagy in breast cancer cells.

Study of carboxymethyl cellulose (CMC) coated manganite as potential candidate for magnetic hyperthermia applications

The present study reports substantial coating of biocompatible polymer Carboxymethyl Cellulose (CMC) on magnetic nanoparticles (MNPs) of Lanthanum Strontium Manganese Oxide (LSMO) also called manganite, as a novel attempt, for magnetic Hyperthermia applications. Two series of manganite (La1-xSrxMnO3) were synthesized through Citrate-gel technique choosing “x” as (0.3) and (0.33). X-ray diffraction (XRD) study has shown satisfactory phase formation of MNPs in accordance with the standard patterns. High resolution transmission electron microscopy (HRTEM) was done to evaluate the effect of CMC on particles’ morphology after coating. The Fourier transform infrared spectroscopy (FTIR) has displayed successful attachment of CMC on the surface of MNPs and adsorbed coating amounts have been assessed through Thermogravimetric analysis and Differential Scanning Calorimetry (TGA/DSC). The coated LSMO were dispersed in Phosphate Buffer Saline (PBS, pH = 7) as an innovative try, to see the potential of these mediators towards effective Hyperthermia applications in fluid form at a suitable frequency of the applied magnetic field. The CMC coated MNPs have achieved quite appreciable specific absorption rate (SAR) up to 225 W/g and intrinsic loss power (ILP); showing a positive sign for their possible usage in Hyperthermia therapy.

Advanced metal oxide infiltrated electrodes for boosting the performance of solid oxide cells

Pr and Mn infiltrated oxide nanoparticles are confirmed as excellent candidates for boosting the performance of standard lanthanum strontium manganese oxygen electrodes.

Effect of Lanthanum Strontium Manganese Oxide (LaSMnO3) Nanoparticle on mouse Testosterone and Fertility

Intraperitoneal administration of Lanthanum strontium manganese oxide (LaSMnO3) a new class of magnetic nanoparticle on mouse testosterone and fertility was investigated. For this, experimental mice divided into 4 groups (n=5); group I, II, III and IV were treated with vehicle (control), 5, 10 and 20 µg/kg/day of LaSMnO3 for 21 days respectively. Five animals from each group were sacrificed at interval of 0, 7, 14 and 21 days, however, after twenty-one days of the treatment, animals in all groups were allowed to cohabited with untreated female mice for fertility study. Toxic effects of LaSMnO3 on the testosterone and sperm parameters were analyzed. Effect on ROS and anti-oxidative biomarkers were also measured. Significant decrease (p<0.05) of epididymal spermatozoa motility and numbers was measured revealing the cytotoxicity effects of this nanomaterial. Light microscopic study revealed changes in the cauda epididymal sperm morphology. Failure of the fertility in LaSMnO3-treated mice as evidenced by the significant reduction in the average number of implantation in females mated with the treated males. Depletion of testicular testosterone hormone level by high dose of LaSMnO3 (20µg/kg/day) shows a reduced testicular androgen synthesis. This study therefore, shows the potential adverse effect of LaSMnO3 on male fertility.
 Keywords: Lanthanum strontium manganese oxide nanoparticle, animal models, toxicity, fertility

Mechanochemically assisted synthesis of La0.7Sr0.3MnO3 nanoparticles and induction heating properties of the composites with hydroxyapatite

Perovskite lanthanum strontium manganese oxide (LSMO, strontium-substituted lanthanum manganite) La0.7Sr0.3MnO3 nanoparticles were synthesized via the low-temperature calcination of the precursor, which was prepared using a mechanochemical route. A powder mixture of lanthanum chloride, strontium chloride, manganese chloride and sodium carbonate was high-energy milled by a planetary ball mill under semiwet (moist) conditions to obtain the precursor. To study the mechanochemical effects on the formation of LSMO, a thermogravimetric (TG) analysis was conducted for the precursors prepared under various conditions; the precursors and the intermediates formed during calcination were identified by X-ray diffraction (XRD). The calcination of the milled precursor at 600 °C resulted in the formation of LSMO nanoparticles with good induction heating properties. The LSMO/hydroxyapatite composites exhibited rapid temperature increases in an AC magnetic field. The obtained results demonstrate that the LSMO nanoparticles and LSMO/hydroxyapatite composites are promising candidates for magnetic hyperthermia treatments.

A robust in vitro anticancer activity via magnetic hyperthermia mediated by colloidally stabilized mesoporous silica encapsulated La0.7Sr0.3MnO3 core- shell structure

In magnetic hyperthermia therapy (MHT), lanthanum strontium manganese oxide (LSMO) has drawn significant attention due to its ability to prevent overheating problems. However, heating efficiency, colloidal stability as well as cell viability imparted by LSMO has limited its application for clinical purpose. To circumvent the above issues, we report a strategy to encapsulate the LSMO within a mesoporous silica shell. The uniform mesoporous coating of silica on LSMO of thickness 9 nm is characterized by TEM. Moreover, the colloidal stability as well as cell viability are found to be significantly improved after silica coating on LSMO as demonstrated by the DLS measurement and MTT assay respectively. The heating efficiency of mesoporous silica encapsulated LSMO nanoparticles (MSLN) under an alternating magnetic field (AMF) of a frequency 350 kHz and amplitude of 14 kA/m is tested and found to have high heating efficiency (255 W/g) and intrinsic loss power found to be 3.7 nHm2/kg. Further linear response theory has been used to numerically evaluate the SAR value to validate the experimental values. In vitro biological characterization data using lung cancer cells (A549) revealed that MSLN resulted in approximately 80 % cell death at nanoparticle dose within the biosafety limit. Cell death pathway analysis showed apoptosis as the predominant mode of cell death at 43 °C. Therefore, the outcomes of this study warrant further testing of MSLN in in vivo models to test them for potential implications in the field of cancer therapy.

High Volumetric Energy Density Sulfur Cathode with Heavy and Catalytic Metal Oxide Host for Lithium-Sulfur Battery.

For high‐energy lithium–sulfur batteries, the poor volumetric energy density is a bottleneck as compared with lithium–ion batteries, due to the low density of both the sulfur active material and sulfur host. Herein, in order to enhance the volumetric energy density of sulfur cathode, a universal approach is proposed to fabricate a compact sulfur cathode with dense materials as sulfur host, instead of the old‐fashioned lightweight carbon nanomaterials. Based on this strategy, heavy lanthanum strontium manganese oxide (La0.8Sr0.2MnO3), with a high theoretical density of up to 6.5 g cm−3, is introduced as sulfur host. Meanwhile, the La0.8Sr0.2MnO3 host also acts as an efficient electrocatalyst to accelerate the diffusion, adsorption, and redox dynamics of lithium polysulfides in the charge–discharge processes. As a result, such S/La0.8Sr0.2MnO3 cathode presents high gravimetric/volumetric capacity and outstanding cycling stability. Moreover, an ultra‐high volumetric energy density of 2727 Wh L−1 ‐cathode is achieved based on the densification effect with higher density (1.69 g cm−3), which is competitive to the Ni‐rich oxide cathode (1800–2160 Wh L−1) of lithium–ion batteries. The current study opens up a path for constructing high volumetric capacity sulfur cathode with heavy and catalytic host toward practical applications of lithium–sulfur batteries.

Ultra-fast fabrication of lanthanum strontium manganese thin films using intense pulsed light irradiation

Commercialization of thin film manufacturing is limited due to the long process time and fabrication cost. To solve these problems, the intense pulsed light sintering method was proposed in this paper. This novel sintering process using xenon lamp irradiation accomplished sintering in milliseconds in ambient air. For evaluation of the sintering effects, wide ranges of irradiation energy densities and substrate temperatures were investigated. The additional thermal energy from bottom-heating results in reducing the required photonic energy density. A flash light sintering process was applied to fabricate a lanthanum strontium manganese (La0.8Sr0.2Mn1O3-δ) perovskite structure used in energy and memory devices. The La0.8Sr0.2Mn1O3-δ thin film was coated by an electrostatic spray deposition (ESD) technique, using chemical deposition. This ESD technique is suitable for the flash light sintering process because a wet chemical method facilitates rapid and low-cost commercial fabrication. After the LSMO thin films were coated, the conventional thermal and flash light sintering processes were conducted, and the properties of the LSMO thin film were evaluated for remnant organics, electrical conductivity, crystallinity, and surface morphology. Flash light sintering delivers a complete sintering process in under 1 s, eliminating the frequent obstacles inherent in thermal sintering.

Encapsulated lanthanum strontium manganese oxide in mesoporous silica shell: Potential for cancer treatment by hyperthermia therapy

We have reported the synthesis of core-shell nanostructure of mesoporous silica coated lanthanum strontium manganese oxide nanoparticles (MSLN) as a potential candidate for cancer treatment via magnetic hyperthermia. N2 adsorption-desorption isotherm revealed that mesoporous silica shell coating increased the surface area and pore volume of lanthanum strontium manganese oxide nanoparticles (LSMO). In comparison to LSMO, MSLN showed a stable colloidal dispersion up to 48 h. In-vitro studies using A549 cells demonstrated increased biocompatibility in MSLN as compared to LSMO. Moreover, cells treated with MSLN exhibited high cell survival rate of up to 1 mg/ml concentration. Further, we used different parameters to modulate the heating efficacies of these nanoparticles. The modulation of specific absorption rates (SAR) with different sample concentrations (0.5, 1, 1.5, 2.0 mg/ml) were studied under four different alternating current magnetic field (AMF) amplitudes (10, 11, 12, 13 kA/m) at a constant frequency of 335 KHz for magnetic hyperthermia experiments. Under the application of AMF, MSLN exhibited faster Néel and Brownian relaxation compared to their LSMO counterparts. SAR value of 295 W/g and intrinsic loss power (ILP) of 5.22 nHm2/kg, at a low sample concentration of MSLN (0.5 mg/ml) were obtained, which was within the clinical limit. Interestingly, our results showed 45% improvement in terms of the heating efficiency over the commercially available products (Table 3). Hence, we conclude that MSLN with high SAR and ILP values, good colloidal dispersion ability and low cytotoxicity could be a potential candidate for magnetic hyperthermia therapy in cancer and warrant further testing in both in-vitro and in-vivo studies. Further, due to their mesoporous nature, MSLN could be considered for target-specific drug delivery applications in clinical therapy.

Structure-property correlations in thermally processed epitaxial LSMO films

Mixed-valence perovskites have drawn significant research interest in the past due to their exotic properties. Lanthanum Strontium Manganese Oxide (LSMO) shows a ferromagnetic ordering that can be tuned with the control of defects and strain. Here, experiments were performed to decouple the effects of strain and oxygen content, which together control the magnetic properties of the LSMO (La0.7Sr0.3MnO3). In this work, thermal treatments show promise in effectively controlling the ferromagnetic response of LSMO films. A set of three samples were grown on the same substrate-buffer (Al2O3/MgO) platform with different oxygen partial pressures and annealed above their deposition temperature (∼900 °C) in air. The physical and structural properties were measured and showed overall decrease in magnetization saturation as well as decrease in out-of-plane lattice spacing with decreasing oxygen partial pressure. A second anneal at lower (∼700 °C) temperature with flow of pure oxygen was performed for six hours to allow for defect annihilation and grain growth. All three films remained epitaxial allowing for direct correlation of magnetic measurements with defect concentration. Partial recovery of the magnetic properties and a slight increase in interplanar spacing was observed. The inability of the films to fully recover their original magnetic properties suggests irreversible strain relaxation during the initial, high-temperature air anneal. This hypothesis was further supported by the in-situ XRD that showed a linear increase in the interplanar spacing with temperature until ∼520 °C for LSMO and ∼690 °C for MgO. With further increase in temperature, the films experienced both loss of oxygen and irreversible defect nucleation and recombination. High resolution high-angle annular dark field (HAADF) images showed uniform thickness and no interfacial mixing with subsequent annealing treatments while electron energy loss spectroscopy (EELS) showed a loss of characteristic pre-peak A in oxygen indicating formation of oxygen vacancies. Parallel annealing experiments in high vacuum instead of atmosphere were performed, which showed complete loss of crystal structure in the LSMO films due to significant loss of oxygen in the lattice that irreversibly collapsed the perovskite structure. Furthermore, a low-temperature (∼500 °C) oxidation anneal was performed on a pristine sample with no change in the interplanar spacing observed indicating no change in the strain state of the film due to annealing below the deposition temperature. The reversibility of magnetic properties, which is observed as long as the crystal structure of the films is preserved, indicates the importance of bridging oxygen in controlling the magnetic behavior of mixed valence perovskites. Finally, it was determined that the highest magnetization saturation in the films is achieved with a high oxygen partial pressure during growth and subsequent thermal annealing below the deposition temperature.

Oxygen Effect on the Properties of Epitaxial (110) La0.7Sr0.3MnO3 by Defect Engineering.

The multiferroic properties of mixed valence perovskites such as lanthanum strontium manganese oxide (La0.7Sr0.3MnO3) (LSMO) demonstrate a unique dependence on oxygen concentration, thickness, strain, and orientation. To better understand the role of each variable, a systematic study has been performed. In this study, epitaxial growth of LSMO (110) thin films with thicknesses ∼15 nm are reported on epitaxial magnesium oxide (111) buffered Al2O3 (0001) substrates. Four LSMO films with changing oxygen concentration have been investigated. The oxygen content in the films was controlled by varying the oxygen partial pressure from 1 × 10-4 to 1 × 10-1 Torr during deposition and subsequent cooldown. X-ray diffraction established the out-of-plane and in-plane plane matching to be (111)MgO ∥ (0001)Al2O3 and ⟨11̅0⟩MgO ∥ ⟨101̅0⟩Al2O3 for the buffer layer with the substrate, and an out-of-plane lattice matching of (110)LSMO ∥ (111)MgO for the LSMO layer. For the case of the LSMO growth on MgO, a novel growth mode has been demonstrated, showing that three in-plane matching variants are present: (i) ⟨11̅0⟩LSMO ∥ ⟨11̅0⟩MgO, (ii) ⟨11̅0⟩LSMO ∥ ⟨101̅⟩MgO, and (iii) ⟨11̅0⟩LSMO ∥ ⟨01̅1⟩MgO. The atomic resolution scanning transmission electron microscopy (STEM) images were taken of the interfaces that showed a thin, ∼2 monolayer intermixed phase while high-angle annular dark field (HAADF) cross-section images revealed 4/5 plane matching between the film and the buffer and similar domain sizes between different samples. Magnetic properties were measured for all films and the gradual decrease in saturation magnetization is reported with decreasing oxygen partial pressure during growth. A systematic increase in the interplanar spacing was observed by X-ray diffraction of the films with lower oxygen concentration, indicating the decrease in the lattice constant in the plane due to the point defects. Samples demonstrated an insulating behavior for samples grown under low oxygen partial pressure and semiconducting behavior for the highest oxygen partial pressures. Magnetotransport measurements showed ∼36.2% decrease in electrical resistivity with an applied magnetic field of 10 T at 50 K and ∼1.3% at room temperature for the highly oxygenated sample.

Barium Oxide (BaO) Infiltrated Lanthanum Strontium Manganese Oxide (LSM)-Gadolinium Doped Ceria (GDC) Solid Oxide Electrochemical Reduction Cells (SOERC) for Reduced Diesel NOx Emissions

Diesel engines are widely used in automobiles for their high fuel efficiency, low carbon monoxide emissions, and low hydrocarbon emissions [1]. Unfortunately, due to their lean-burn operating environment, diesel engines emit higher amounts of NOx than gasoline engines. Although NOx Storage and Reduction (NSR) and Selective Catalytic Reduction (SCR) technologies have been commercialized and offer high deNOx (i.e. NOx decomposition) efficiency, they suffer from a loss of fuel efficiency during catalyst regeneration and a need for large-volume, on-board ammonia storage and replenishment, respectively [2]. Further, expensive precious metal catalysts are needed to enable deNOx chemical reactions in these conventional technologies. In contrast, Solid Oxide Electrochemical Reduction Cells (SOERCs) utilizing an external bias to electrochemically drive NOx decomposition promise precious-metal-free operation without the need for catalyst regeneration or large-volume, on-board storage. Here, the deNOx performance of barium oxide (BaO) infiltrated lanthanum strontium manganese oxide (LSM)-gadolinium doped ceria (GDC) SOERCs were measured as a function of operating temperature, AC amplitude, and AC frequency. Under all test conditions, SOERC performance was reproducible across different samples with the application, removal, and subsequent reapplication of electrical bias. The BaO-LSM-GDC SOERCs tested here displayed better low-temperature NOx conversion efficiencies than those previously reported in the literature; achieving 22% at 350oC compared to the 3% reported in the literature [3, 4]. In agreement with this literature 1) the application of an AC electric bias was found to produce higher BaO-LSM-GDC NOx conversion efficiencies than a DC bias of the same magnitude, and 2) BaO-LSM-GDC SOERCs exhibited current and thermodynamic efficiencies of a few percent, and a few tenths of a percent, respectively. Unfortunately, as shown previously [3, 4], these conversion efficiencies decreased by several percent after only a few hours of operation at 450oC due to microstructural coarsening of the BaO infiltrate.

Barium Oxide (BaO) Infiltrated Lanthanum Strontium Manganese Oxide (LSM)-Gadolinium Doped Ceria (GDC) Solid Oxide Electrochemical Reduction Cells (SOERC) for Reduced Diesel NOx Emissions

Diesel engines are widely used for transportation applications because of their high fuel efficiency, low carbon monoxide emissions, and low hydrocarbon emissions. Unfortunately, due to their lean-burn operating environment, diesel engines emit higher amounts of NOx than gasoline engines. Further, common NOx decomposition methods suffer from high precious metal costs and a loss in vehicle efficiency. Here, the NOx decomposition performance of barium oxide (BaO) infiltrated lanthanum strontium manganese oxide (LSM)-gadolinium doped ceria (GDC) Solid Oxide Electrochemical Reduction Cells (SOERCs) were measured as a function of operating temperature, AC amplitude and AC frequency. Under all test conditions, SOERC performance was reproducible across different samples with the application, removal, and subsequent reapplication of electrical bias. The BaO-LSM-GDC SOERCs tested here displayed higher than expected low-temperature NOx conversion efficiencies of 22% at 350 °C.

Applying Capacitive Energy Storage for In Situ Manipulation of Magnetization in Ordered Mesoporous Perovskite-Type LSMO Thin Films.

Mesostructured nonsilicate materials, particularly mixed-metal oxides, are receiving much attention in recent years because of their potential for numerous applications. Via the polymer-templating method, perovskite-type lanthanum strontium manganese oxide (La1-xSrxMnO3, LSMO, with x ≈ 0.15 to 0.30) with a continuous 3D cubic network of 23 nm pores is prepared in thin-film form for the first time. Characterization results from grazing incidence X-ray scattering, X-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, and electron microscopy and tomography show that the dip-coated sol-gel-derived films are of high quality in terms of both composition and morphology and that they are stable to over 700 °C. Magnetic and magnetotransport measurements demonstrate that the material with the highest strontium concentration is ferromagnetic at room temperature and exhibits metallic resistivity behavior below 270 K. Besides, it behaves differently from epitaxial layers (e.g., enhanced low-field magnetoresistance effect). It is also shown that carriers (electrons and holes) can be induced into the polymer-templated mesostructured LSMO films via capacitive double-layer charging. This kind of electrostatic doping utilizing ionic liquid gating causes large relative changes in magnetic susceptibility at room temperature and is a viable technique to tune the magnetic phase diagram in situ.

Hyperthermia mediated by dextran-coated La0.7Sr0.3MnO3 nanoparticles: in vivo studies.

PurposeThe aim of this study was to evaluate radiofrequency-induced dextran-coated lanthanum strontium manganese oxide nanoparticles-mediated hyperthermia to be used for tumor regression in mice.Materials and methodsNanoparticles were injected intra-tumorally in melanoma-bearing C57BL/6J mice and were subjected to radiofrequency treatment.ResultsHyperthermia treatment significantly inhibited tumor growth (~84%), increased survival (~50%), and reduced tumor proliferation in mice. Histopathological examination demonstrated immense cell death in treated tumors. DNA fragmentation, increased terminal deoxynucleotidyl transferase-dUTP nick end labeling signal, and elevated levels of caspase-3 and caspase-6 suggested apoptotic cell death. Enhanced catalase activity suggested reactive oxygen species-mediated cell death. Enhanced expression of heat shock proteins 70 and 90 in treated tumors suggested the possible development of “antitumor immunity”.ConclusionThe dextran-coated lanthanum strontium manganese oxide-mediated hyperthermia can be used for the treatment of cancer.