Magnetic and Cytotoxicity Properties of La1−xSrxMnO3(0 ≤ x ≤ 0.5) Nanoparticles Prepared by a Simple Thermal Hydro-Decomposition

This study reports the magnetic and cytotoxicity properties of magnetic nanoparticles of La1−xSrxMnO3(LSMO) withx = 0, 0.1, 0.2, 0.3, 0.4, and 0.5 by a simple thermal decomposition method by using acetate salts of La, Sr, and Mn as starting materials in aqueous solution. To obtain the LSMO nanoparticles, thermal decomposition of the precursor was carried out at the temperatures of 600, 700, 800, and 900 °C for 6 h. The synthesized LSMO nanoparticles were characterized by XRD, FT-IR, TEM, and SEM. Structural characterization shows that the prepared particles consist of two phases of LaMnO3(LMO) and LSMO with crystallite sizes ranging from 20 nm to 87 nm. All the prepared samples have a perovskite structure with transformation from cubic to rhombohedral at thermal decomposition temperature higher than 900 °C in LSMO samples ofx ≤ 0.3. Basic magnetic characteristics such as saturated magnetization (MS) and coercive field (HC) were evaluated by vibrating sample magnetometry at room temperature (20 °C). The samples show paramagnetic behavior for all the samples withx = 0 or LMO, and a superparamagnetic behavior for the other samples havingMSvalues of ~20–47 emu/g and theHCvalues of ~10–40 Oe, depending on the crystallite size and thermal decomposition temperature. Cytotoxicity of the synthesized LSMO nanoparticles was also evaluated with NIH 3T3 cells and the result shows that the synthesized nanoparticles were not toxic to the cells as determined from cell viability in response to the liquid extract of LSMO nanoparticles

NF-κB Mediates Tumor Necrosis Factor α-Induced Expression of Optineurin, a Negative Regulator of NF-κB

Optineurin is a ubiquitously expressed multifunctional cytoplasmic protein encoded by OPTN gene. The expression of optineurin is induced by various cytokines. Here we have investigated the molecular mechanisms which regulate optineurin gene expression and the relationship between optineurin and nuclear factor κB (NF-κB). We cloned and characterized human optineurin promoter. Optineurin promoter was activated upon treatment of HeLa and A549 cells with tumor necrosis factor α (TNFα). Mutation of a putative NF-κB-binding site present in the core promoter resulted in loss of basal as well as TNFα-induced activity. Overexpression of p65 subunit of NF-κB activated this promoter through NF-κB site. Oligonucleotides corresponding to this putative NF-κB-binding site showed binding to NF-κB. TNFα-induced optineurin promoter activity was inhibited by expression of inhibitor of NF-κB (IκBα) super-repressor. Blocking of NF-κB activation resulted in inhibition of TNFα-induced optineurin gene expression. Overexpressed optineurin partly inhibited TNFα-induced NF-κB activation in Hela cells. Downregulation of optineurin by shRNA resulted in an increase in TNFα-induced as well as basal NF-κB activity. These results show that optineurin promoter activity and gene expression are regulated by NF-κB pathway in response to TNFα. In addition these results suggest that there is a negative feedback loop in which TNFα-induced NF-κB activity mediates expression of optineurin, which itself functions as a negative regulator of NF-κB

Facile green synthesis, characterization and transport properties of LiAlSiO4:Ce3+ nanocomposites

The LiAlSiO4:Ce3+ (0-11 mol%) nanocomposites are synthesized by low temperature solution combustion method using aloe vera gel as a fuel. The prepared samples are characterized by powder X-ray diffraction (XRD) to know the crystallite size, optical energy band gap by Kubelka-Munk (K-M) plot and surface morphology by scanning electron microscope (SEM) coupled with energy dispersive X-ray (EDX) analysis for elemental confirmation. The stretching frequency of all nanocomposites is confirmed by Fourier transform infrared (FTIR) spectra. The Raman spectroscopy provides a structural fingerprint by which molecules can be identified. The current-voltage (I-V) characteristics showed that the prepared samples obey Ohm's law. DC conductivity is studied for temperature ranging from 30-450 degrees C and activation energy is calculated by Arrhenius plot. Further, the present method was reliable, environmental friendly and alternative to economical routes

Swift heavy ion induced thermoluminescence studies in polycrystalline aluminum oxide

When energetic swift heavy ions interact with matter, inelastic collision (leading to electronic energy loss-Se) and elastic collision (leading to nuclear energy loss -Sn) take place. In the present study, the effect of energetic ion species on thermoluminescence (TL) of polycrystalline aluminum oxide (PAO) is reported. PAO pellets of 6 mm diameter are irradiated with energetic Au9+, Ni7+ and Si7+ ions for the fluence of 1×1013 ions cm-2. A single well resolved prominent TL glow with peak at 538 K is observed in Si7+ irradiated samples. However, in Ni7+ and Au9+ irradiated samples a prominent TL glow with peak at 610 K along with a shoulder at 513 K is observed. On the other hand, when PAO samples are irradiated with g-rays two well separated TL glows with peaks at 483 K and 638 K are observed. A prominent PL emission with peak at 430 nm besides a weak emission with peak at 480 nm and a shoulder at 525 nm are observed in 120 MeV Au9+ion irradiated samples when excited with 320 nm. These PL peaks are attributed to F, F2+ and F22+-centers respectively. However, in Si7+ irradiated samples a single PL emission peak at 430 nm is observed and it is attributed to F-centers

Dy3+ doped Y2MoO6 nanopowders for white light emission: Spectroscopic and transport properties for optoelectronic and energy harvesting applications

In this communication, we report the white light emitting Dy3+ ions doped Y2MoO6 (YMO) nanopowders (NPs) prepared via green combustion synthesis route by utilizing the Aloe vera (AV) gel as surfactant. For the convenient to the readers, we represent Y2MoO6:Dy3+ as YMOD. The cubic structure of the YMOD is confirmed by the results of powder X-ray diffraction (PXRD). The energy band gap values are studied by diffuse reflectance spectra (DRS) plots and the observed values are found to be in the range of 3.33-3.43 eV. The block-like structures of the fabricated nanopowders is analyzed by means of scanning electron microscope (SEM) images. Transmission electron microscope (TEM) images are castoff to evaluate the particle size of the prepared powders. The crystallinity and interplanar spacing are analyzed by means of selected area diffraction (SAED) and high-resolution TEM (HRTEM) images respectively. In order to study the luminescence behaviour of the fabricated powders, the photoluminescence spectra are recorded in the range of 400-675 nm under 386 nm excitation wavelength. There are three prominent peaks positioned at 480, 575 and 637 nm which are corresponding to the F-4(9/2) -> H-6(15/2), (13/2) and 11/2 respectively. The direct current conductivity is studied in the temperature range from 30 to 400 degrees C. The DC conductivity of NPs increases with increase in temperature. The color emission of the fabricated powders is studied by means of color diagrams namely, CIE and CCT. It is noticed from the color diagrams that, the emission color lies in the bright white region (0.33, 0.33) which is a characteristic emission of the Dy3+ doped powders. The obtained CCT value (5426 K) indicates that the prepared powders can be effectively utilized for cool LED sources in the indoor lighting applications. The average color purity (CP) values are found to be 80%. The quantum efficiency of the prepared nanopowders is found to be similar to 86.82%. The above findings substantiate the ability of YMO: Dy3+ phosphor to be used in photovoltaic and display device applications