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The salient features of this research article are following:
•Mixed phase synthesis of Cu/Cu2O/CuO nanoparticles prepared by Exploding Wire Technique (EWT).•Predominant Cu/Cu2O phases ...along with minor CuO phase revealed through XRD, TEM, Raman, FTIR, UV–Visible and PL analyses.•XPS analysis provided direct evidences of Cu2+ and Cu+ along with O deficiency for prepared nanoparticles.•Room temperature weak ferromagnetic behaviour was demonstrated for Cu/Cu2O/CuO nanoparticles.
In this article, we explore potential of Exploding Wire Technique (EWT) to synthesize the copper nanoparticles using the copper metal in a plate and wire geometry. Rietveld refinement of X-ray diffraction (XRD) pattern of prepared material indicates presence of mixed phases of copper (Cu) and copper oxide (Cu2O). Agglomerates of copper and copper oxide comprised of ∼20nm average size nanoparticles observed through high resolution transmission electron microscope (HRTEM) and energy dispersive x-ray (EDX) spectroscopy. Micro-Raman (μR) and Fourier transform infrared (FTIR) spectroscopies of prepared nanoparticles reveal existence of additional minority CuO phase, not determined earlier through XRD and TEM analysis. μR investigations vividly reveal cubic Cu2O and monoclinic CuO phases based on the difference of space group symmetries. In good agreement with μRaman analysis, FTIR stretching modes corresponding to Cu2-O and Cu-O were also distinguished. Investigations of μR and FTIR vibrational modes are in accordance and affirm concurrence of CuO phases besides predominant Cu and Cu2O phase. Quantum confinement effects along with increase of band gaps for direct and indirect optical transitions of Cu/Cu2O/CuO nanoparticles are reflected through UV–vis (UV–vis) spectroscopy. Photoluminescence (PL) spectroscopy spots the electronic levels of each phase and optical transitions processes occurring therein. Iterative X-ray photoelectron spectroscopy (XPS) fitting of core level spectra of Cu (2p3/2) and O (1s), divulges presence of Cu2+ and Cu+ in the lattice with an interesting evidence of O deficiency in the lattice structure and surface adsorption. Magnetic analysis illustrates that the prepared nanomaterial demonstrates ferromagnetic behaviour at room temperature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The hematological malignancies classified as mixed lineage leukemias (MLL) harbor fusions of the MLL1 gene to partners that are members of transcriptional elongation complexes. MLL-rearranged ...leukemias are associated with extremely poor prognosis, and response to conventional therapies and efforts to identify molecular targets are urgently needed. Using mouse models of MLL-rearranged acute myeloid leukemia, here we show that genetic inactivation or small-molecule inhibition of the protein arginine methyltransferase PRMT5 exhibit anti-tumoral activity in MLL-fusion protein-driven transformation. Genome-wide transcriptional analysis revealed that inhibition of PRMT5 methyltransferase activity overrides the differentiation block in leukemia cells without affecting the expression of MLL-fusion direct oncogenic targets. Furthermore, we find that this differentiation block is mediated by transcriptional silencing of the cyclin-dependent kinase inhibitor p21 (CDKN1a) gene in leukemia cells. Our study provides pre-clinical rationale for targeting PRMT5 using small-molecule inhibitors in the treatment of leukemias harboring MLL rearrangements.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The structural, magnetic and dielectric properties of the hexagonal four-layered form of SrMnO
3
along with its fluorinated counterpart have been investigated. Among these, the fluorinated hexagonal ...four-layered compound is being reported for the first time. Although the bulk crystal structure does not change with fluorination, there are clear spectroscopic evidences of local chemical fluorination having disordered Mn-F rich phases in the fluorinated compound. Fluorination of bulk antiferromagnetic SrMnO
3
changes the magnetic properties considerably where a spin- or cluster-glass-like state appears below 42 K with a large exchange bias. In addition to that, the F-doped SrMnO
3
indicates development of polarization and the system exhibits ferroelectric nature which has been confirmed through the strain-electric field (
S
-
E
) hysteresis loop.
The structural, magnetic and dielectric properties of the hexagonal four-layered form of SrMnO
3
along with its fluorinated counterpart have been investigated.
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•Detection of low concentration SO2 gas by Ca-substituted LaFeO3 nanoparticles.•A remarkable increase in gas sensing performance of thin film over pellet.•High selectivity to SO2 gas ...over other hazardous gases at low operating temperature.•Mechanistic insights obtained from DFT calculations for the strong binding of SO2.
A comparative study of La1-xCaxFeO3 (0.4 ≤ x ≤ 0.8) pellets and La0.6Ca0.4FeO3 thin films for the selective detection of low concentration SO2 gas has been performed. The La0.6Ca0.4FeO3 thin films exhibited superior gas sensing performance than La1-xCaxFeO3 (0.4 ≤ x ≤ 0.8) pellets in terms of sensitivity, operating temperature, detection limit, response, and recovery time. The HRTEM images confirm the nanoparticle nature of the La1-xCaxFeO3 (0.4 ≤ x ≤ 0.8) samples. The material crystallizes in the orthorhombic crystal system with the Pbnm space group. Further, occupancy refinement of neutron diffraction data indicates the presence of oxygen vacancies which was also supported by XPS analysis. Among the various compositions of La1-xCaxFeO3 (0.4 ≤ x ≤ 0.8), the x = 0.4(La0.6Ca0.4FeO3) was found to exhibit the best gas sensing performance and chosen for thin film preparation. The gas sensing studies of thin films, prepared by the DC magnetron sputtering method, confirm the enhanced gas sensitivity towards 3 ppm SO2 gas at a low operating temperature of 120 °C. The selectivity studies show that La1-xCaxFeO3 (0.4 ≤ x ≤ 0.8) preferentially detects SO2 gas at the given operating condition over other gases such as CH4, CO2, and CO. The gas sensing mechanism and high sensitivity of the La1-xCaxFeO3 sensor towards the detection of SO2 gas were explained by DFT calculations which give evidence for the strong binding of SO2 molecules on the 121 surface of the sensor.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The present work investigates the superior ability of LaFeO
3
(LaFeO) and La
0.8
Ca
0.2
FeO
2.95
(LaCaFeO) nanoparticles to detect 3 ppm SO
2
gas. The influence of calcium substitution on the sensing ...behaviour of LaFeO has been studied. High resolution TEM images show that the particle sizes of LaFeO and LaCaFeO are less than 100 nm and SEM images show the agglomeration of interconnected nanoparticles. Both LaFeO and LaCaFeO crystallize in the orthorhombic crystal system with the space group
Pbnm
. Rietveld analysis of neutron diffraction data showed that LaCaFeO has lattice oxygen vacancies. In addition, magnetic refinements on both the samples have been carried out. The presence of lattice oxygen vacancies in LaCaFeO is qualitatively supported by Raman and XPS measurements. Electrical characterization showed increased conductivity for the LaCaFeO sample, influencing their sensing performance significantly. The LaCaFeO nanoparticles exhibit higher sensitivity, faster response time, rapid recovery time and good recyclability for sensing 3 ppm SO
2
gas. This enhanced sensing behaviour is attributed to the increased oxygen vacancies in the lattice as well as the surface. As a consequence, increased active sites are created in LaCaFeO, promoting redox reaction between the analyte and the sensing material. The results demonstrated that while LaFeO is a good gas sensor, p-type substitution by Ca
2+
renders this material an improved resistivity based gas sensor to detect low concentration SO
2
.
Resistivity based sensing for the detection of 3 ppm SO
2
gas by using LaFeO and LaCaFeO nanoparticle sensors.
The CoHoxFe2-xO4 (x = 0.00, 0.05, 0.1, 0.15, 0.2) samples were synthesized by chemical co-precipitation technique. The structural properties were studied using X-ray diffraction (XRD). XRD data ...reveal formation of single cubic spinel phase for the samples having lower concentration of holmium substitution namely x = 0.0, 0.05 and 0.10, However, at higher concentrations, x = 0.15 and 0.2 few extra diffraction lines belonging to HoFeO3 were observed indicating solubility limit of holmium in the CoFe2O4 lattice. Williamson – Hall plot was used to determine strain in the samples. Microstructural studies carried out using Scanning Electron Microscopy (SEM) depict significant changes in microstructure with increase in holmium concentration. Microstructure of un-substituted cobalt ferrite sample was found to be very compact and grain growth was further found to be restricted with increase in holmium concentration. DC magnetization recorded using Vibrating Sample Magnetometer (VSM) at room temperature indicates decrease in saturation magnetization with increase in Holmium concentration, which is correlated with the weakening of A-B exchange interactions. Comparatively high values of coercivity and retentivity are obtained for holmium concentration with x = 0.15. Magnetostriction measurements were carried out for two different orientations of strain gauge fixed on plane surface of sample with parallel and perpendicular orientation with respect to direction of external magnetic field. For un-substituted cobalt ferrite sample, maximum value of magnetostriction was found to be −228 ppm at 3.5 kG magnetic field. This suggests its application in actuator. Further, effect of holmium substitution on magnetic and magnetostrictive properties has been analyzed.
•Successful synthesis of Ho doped Co ferrite for low concentrations of Ho ion.•Interesting results obtained in magnetization and magnetostriction data.•Well accounting of and sufficient explanation given for the obtained results.•Stress sensitivity suggests application of these materials in sensing devices.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Given the enormous and rising global need for permanent magnet supply, even minor enhancements to the magnetic characteristics and economic viability of permanent magnet materials could result in ...significant energy and financial savings. In this work, the experimental conditions were optimized in order to produce barium hexaferrite (BaFe
12
O
19
) substituted with transition elements (Co and Mn) through chemical co-precipitation method. Powder X-ray Diffraction (XRD), Transmission Electron Microscope (TEM) and Fourier Transform Infra-red (FTIR) were used to reveal the structure, morphology and vibrational spectrum of the sample. The site preference for cobalt and manganese was estimated using Rietveld refinement of the XRD spectrum. It is obvious that Co and Mn occupied two crystallographic inequivalent sites, 4f
2
and 4f
1
respectively. Investigation of magnetic properties (VSM) at room temperature showed that as Co and Mn concentrations increase, saturation magnetization and retentivity increase, but coercivity decreases. At higher substitution concentrations, the behavior is the inverse. The possible reasons for these behaviors were discussed. The close correlation between site selection by the dopant and magnetic properties is also demonstrated.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Ni-Cr-Mo based superalloys often precipitate out particles of an ordered Ni2(Cr,Mo) phase in the γ-matrix, whose kinetics varies with composition of alloys. Precipitation of the Ni2(Cr,Mo) phase ...involves a change in the unit cell from cubic to orthorhombic structure. Lattice misfit strains associated with such cubic to non-cubic transformations significantly affect precipitation behaviour. In the present work, a series of Ni-Cr-Mo alloys have been investigated in order to study the effect Cr and Mo solutes on lattice parameters of disordered as well as ordered phases, and its manifestation on precipitation behaviour of the Ni2(Cr,Mo) phase. Lattice parameters have been determined on the basis of Rietveld refinement of x-ray and neutron diffraction data obtained from different alloys in solution treated as well as aged conditions. Present results have shown that lattice misfit strains in these alloys increases monotonously with the increase of Mo/Cr ratio, which significantly affects the precipitation behaviour of the ordered Ni2(Cr,Mo) phase.
•Increase of unit cell parameters of ordered Ni2(Cr,Mo) phase and disordered γ-phase in Ni-Cr-Mo alloys with increase of Mo.•Increase in lattice misfit strains with increase in Mo concentration in aged Ni-Cr-Mo alloys.•Significant effect of lattice misfit strains on the precipitation behavior of the ordered Ni2(Cr,Mo) phase.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Using solution chemical method, the micron sized K0.7MnO2 particles were prepared for K-ion batteries.•The reversible specific capacity reaches 79 at 20 mA/g and 31 mAh/g at 400 mA/g.•A capacity ...retention upto 34% after 400 cycles at 100 mA/g.
Large-scale energy storage and depleting lithium resources spurred interest in efficient, abundant, low-cost potassium ion battery electrode materials. In this regard, the layered K0.7MnO2 cathode was prepared by the solution chemical method. The structural and morphological analyses were performed using XRD, SEM and TEM techniques. The electrochemical properties exhibited multiple redox peaks in CV, indicating the various phase transitions during the intercalation/ de-intercalation and ordering of K-ions in the interlayer. The prepared K-ion cell delivered a reversible specific capacity of 79 and 31 mAh/g at the current densities of 20 and 400 mA/g. The structural integrity accounted for better electrochemical performance from the initial discharge capacities at high current rates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Low temperature neutron diffraction data reveal non-collinear magnetic structure in Co4Ta2O9.•Neutron diffraction data fit best to a non-centro-symmetric crystal structure below Neel ...temperature.•Correlation between magnetic structure and improper ferroelectricity is analyzed for Co4Ta2O9.•Co-existing large magnetoelectric coupling is determined in the spin-flop phase of Co4Ta2O9.
We study magnetocapacitance (MC) effect and magnetoelectric (ME) coupling in spin-flop driven antiferromagnet Co4Ta2O9. Powder neutron diffraction data reveal that the magnetic structure corresponds to a non-collinear arrangement along with a non-centrosymmetric crystal structure below Néel Temperature. Electric polarization is achieved below Néel temperature only when the sample is cooled in the presence of external magnetic field. The magnetocapacitance data at high magnetic fields are analyzed by phenomenological Ginzburg-landau theory of ferro-electromagnets and it is found that change in dielectric constant is proportional to the square of magnetization. The saturation polarization and magnetoelectric coupling are estimated to be 52 µC/m2 and γ = 1.4 × 10−3 (emu/g)−2 respectively at 6 Tesla. Strong magnetoelectric coupling and ferroelectric phase in the anti-ferromagnetic Co4Ta2O9 are correlated to magnetic structure as derived from neutron diffraction data.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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