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X-ray magnetic circular dichroism (XMCD) measurements of iron nano-islands grown on graphene and covered with a Au film for passivation reveal that the oxidation through defects in the Au film spontaneously leads to the formation of magnetite nano-particles (i.e., Fe3O4). The Fe nano-islands (20 and 75 monolayers; MLs) are grown on epitaxial graphene formed by thermally annealing 6H-SiC(0001) and subsequently covered, in the growth chamber, with nominal 20 layers of Au. Our X-ray absorption spectroscopy and XMCD measurements at applied magnetic fields show that the thin film (20 ML) is totally converted to magnetite, whereas the thicker film (75 ML) exhibits properties of magnetite but also those of pure metallic iron. Temperature dependence of the XMCD signal (of both samples) shows a clear transition at TV ≈ 120K consistent with the Verwey transition of bulk magnetite. These results have implications on the synthesis of magnetite nano-crystals and also on their regular arrangements on functional substrates such as graphene. [ABSTRACT FROM AUTHOR]

Highlights • Magnetic particle spectroscopy (MPS) study of nanoparticles in gelatin. • MPS excitation amplitude shown to influence gelatin melting temperature. • Gelatin sample in MPS is too dilute to show macroscopic heating during MPS. • Field-modulated melting suggests microscopic effects. • Evidence for non-negligible particle-matrix interaction during MPS. Abstract Interactions between magnetic nanoparticles (MNPs) and their surrounding matrix were investigated during temperature-controlled magnetic particle spectroscopy (MPS). MNPs are used as tracers in emerging biomedical imaging technologies, including magnetic particle imaging (MPI), which employ spatially inhomogeneous time-varying magnetic fields to generate imaging signals. For safe and reliable imaging procedures, it is important to understand the thermal and mechanical interactions between MNPs and the surrounding biological matrix. We performed in-vitro investigations using magnetic field hyperthermia (MFH) and temperature-controlled MPS to elucidate the excitation-field dependent MNP-matrix interaction. MFH measurements of ferucarbotran (FCT) MNPs were conducted using a low-frequency, high-amplitude, set-up designed to emulate the typical field conditions employed in MPI. First, it was tested whether concentrated FCT samples produce measurable heating in MFH characterization. A strong bulk heating effect (ΔT = 40 K) was observed, showing that the individual MNPs dissipate a significant quantity of heat. However, no measurable bulk temperature increase occurred during MFH of dilute FCT preparations in liquid or gelatin suspensions. Then, temperature-controlled MPS measurements were performed on dilute FCT immobilized in gelatin. The melting transition of the dilute gelatin preparation produced a clear change in the temperature-dependent MPS spectra. The melting transition was reproducible between measurements using the same field excitation, with a standard deviation of σ = 0.2 K. The melting transition temperature was found to depend upon the amplitude of the MPS excitation field. A reduction in the melting transition onset temperature of 2.3 K was observed when the excitation amplitude was increased from 6 mT to 25 mT. This shift is attributed to increasing mechanical and thermal particle-matrix interactions at higher excitation fields. The results show that within the studied system, individual MNPs interact with their local environment in a non-negligible way during MPS measurement, even when bulk heating of the sample is not detected. Our findings hold significance for the potential impact of MPI and related technologies on living tissues, a subject deserving of further study. [ABSTRACT FROM AUTHOR]

Abstract A novel phototherapeutic agent IABDP which possessed the near infrared absorbing was synthesized and characterized. The IABDP can self-assemble into ∼200 nm nanoparticles (IABDP NPs) with high stability by reprecipitation method. Under the low power light irradiation, it exhibits the excellent photodynamic therapy (PDT), while increasing the irradiated power, it exhibits significant photothermal therapy (PTT). Moreover, the particles can generate severe damage to HeLa and HepG2 cells and obvious inhibition effect to the tumor via synergistic PDT/PTT treatments. Graphical abstract Image 1 Highlights • A novel NIR absorption photosensitizer IABDP has been obtained by facile synthetic procedure. • The molecule based on PEGylation aza-BDP could self-assemble into nanoparticles with high stability. • The introduction of iodine atoms significantly generated the photodynamic and photothermal effect. • The aza-BDP nanoparticles can effectively inhibit cancer cells as well as tumors. [ABSTRACT FROM AUTHOR]

In the present work, an investigation of wavelength-dependent absorption spectrum of spherical nanoparticles with different arrangements in organic medium using discrete dipole approximation (DDA) has been performed. Specifically, we study the impact of different arrangements such as monomer, dimer (compositionally symmetric and asymmetric), 1D array of spherical nanoparticle on surface plasmon resonance (SPR) peak position, and its spectral broadening in distinct regimes of the electromagnetic spectrum. Three different organic materials such as P3HT:PCBM blend (Poly(3-hexyl thiophene))-(phenyl-C61-buryricacid methyl ester), P3HT(poly (3-hexyl thiophene)), and PEOPT ((4’-(1”, 4”, 7”-trioaoctyl) phenyl) theophany) have been chosen in the present work to study the absorption and scattering spectrum of MNP. Further, near-field pattern of homo-dimer nanogeometry is also shown in the present study. We also observed that on increasing the interacting number of particles in 1D array, the corresponding FWHM (full width at half maxima) value increases as well, which covers the large spectral region of the electromagnetic spectrum. The comparison between dipole model and numerical model has been performed to analyze the extinction behavior of smaller size (d << λ) metal nano dimer which shows a good agreement in 400-600nm wavelength range. [ABSTRACT FROM AUTHOR]

This work deals with the preparation of novel photocatalysts based on the assembly of ZnO nanoparticles on the surface of sepiolite (Sep) fibrous clay mineral, which can be previously modified by treatment with cetyltrimethylammonium bromide, tetramethoxyortosilicate or magnetite (Fe 3 O 4 ) nanoparticles. The structural and morphological features of the prepared samples were characterized by diverse experimental techniques. The photoactivity of the resulting materials has been tested under solar light irradiation for the degradation of emerging pollutants, such as ibuprofen, acetaminophen and antipyrine. The resulting ZnO/Sep heterostructure exhibits enhanced photocatalytic performance compared to ZnO/SiO 2 -Sep and ZnO/Fe 3 O 4 -Sep materials. Ibuprofen showed higher degradation rates than the other target compounds. Of particular interest is the use of ZnO/Fe 3 O 4 -Sep photocatalyst, which shows the simultaneous features of superparamagnetic character and photocatalytic activity, allowing its easy recovery by application of an external magnetic field which improves its reusability. [ABSTRACT FROM AUTHOR]

Studying the complexes of inorganic nanoparticles - organic dye molecules is of great importance for their theranostics application. In this paper, we report gadolinium-yttrium orthovanadate nanoparticles (VNPs) - Acridine Orange (AO) complex formation in water solutions. To study the interactions between VNPs and AO, the methods of steady-state and time-resolved spectroscopy were used. It was shown that in aqueous solutions containing VNPs, AO aggregation takes place with a sandwich-like stacking of AO molecules in the near-surface layer of VNPs. The VNPs-AO complex formation causes significant changes in the AO fluorescence spectrum, namely, the appearance of a new broad, structureless band in the long-wavelength spectral edge, which was not observed in AO spectrum in a pure water solution. By analyzing of the absorption, fluorescence excitation spectra and fluorescence decay, the static excimer origin of the long-wavelength fluorescence band has been established. [ABSTRACT FROM AUTHOR]

The N-doped porous carbon (NC) has been regarded as one of the promising support materials for nanoparticles (NPs) catalyst due to its inherent virtues such as porosity, large surface areas, and heteroatom incorporation. In this work, Fe/NC-800 hybrid was facilely prepared by uniform dispersion of in situ formed FeNPs onto NC-800 from carbonization of ZIF-8 at 800 °C for the first time. The optimized Fe/NC-800 catalyst was characterized by TEM, XPS and XRD. Compared with sole FeNPs and NC-800, the Fe/NC-800 catalyst exhibited an enhanced oxidase-like activity that could oxidize the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to the heavy blue without extra oxidants such as H 2 O 2 . The possible reason for the enhanced oxidase-like activity of the Fe/NC-800 was discussed on the basis of the experiments of radical scavengers, indicating the importance of superoxide (O 2 •- ) and singlet ( 1 O 2 ) in colorimetric reaction between TMB and Fe/NC-800 hybrid. Furthermore, the oxidase-like activity of Fe/NC-800 was significantly inhibited by dopamine (DA), leading to blue color fading. On this basis, a sensitive and selective colorimetric sensor was fabricated for the quantitative analysis of DA with a linear range of 0.01–40 μM and a low detection limit of 10 nM. The proposed colorimetric method was successfully applied to determine DA in human serum and injection samples, suggesting a promising application in biological analysis. [ABSTRACT FROM AUTHOR]

A MOF material, Co 3 [Co(CN) 6 ] 2 nanoparticles has been prepared for the effective detection of ethanol in vapor phase. When exposed to ethanol vapor, the material was changed from pink to purple, which is easily observed by naked eyes directly. We propose that the ethanol response is due to ethanol molecules entering the pores of the solid, where they alter the coordination geometry, leading to conversion of their Co centers from octahedral to tetrahedral coordination. Significantly, the change is reversible, which make the material reusable without subjecting to dynamic vacuum or slightly warming. [ABSTRACT FROM AUTHOR]

The complex SnO 2 nanoparticles and nanosheets have been synthesized by a facile hydrothermal method. The concentrations of urea play an important role to control the morphology of SnO 2 nanostructures. The complex SnO 2 nanoparticles and nanosheets have excellent photocatalytic activity, which are ascribed to stronger defect emission, higher light harvesting ability in the visible light region, and higher surface-to-volume ratio, which exhibit a much better photocatalytic activity rather than commercial ZnO and TiO 2 nanopowders under a blue light LED irradiation. The complex SnO 2 nanoparticles and nanosheets provide a facile, low cost, high surface-to-volume ratio, high efficiency and stability visible-light-driven photocatalysts for environmental remediation and energy conversion. [ABSTRACT FROM AUTHOR]

A laser focal intensity profiling method based on the forward scattering from a nanoparticle is demonstrated for in situ measurements using a laser focusing system with six microscope objective lenses with different numerical apertures ranging from 0.15 to 1.4. The measured profiles showed Airy disc patterns although their rings showed some imperfections due to aberrations and misalignment of the test system. The dipole radiation model revealed that the artefact of this method was much smaller than the influence of the deterioration in the experimental system; a condition where no artefact appears was predicted based on proper selection of measurement angles. [ABSTRACT FROM AUTHOR]

XRD and TEM characterisation evidenced the formation of well-dispersed CdS nanoparticles inside a phosphate glass matrix. Optical absorption and time-resolved photoluminescence study were carried out on the prepared glass samples. Optical absorption revealed the fast character of the growth of CdS nanoparticles in this medium. Photoluminescence spectra showed only one large band with a maximum at almost 740 nm, which was associated to transitions between energy levels within the bandgap of the CdS nanoparticles. From the steady state and time-resolved measurements, it was suggested that the emission comes mainly from sulfur vacancies inside the nanocrystals and on its surface, which act as deep traps for the photogenerated electrons. The creation of such vacancies was attributed to the loss of sulfur during the glass preparation as evidenced from a chemical analysis using energy dispersive X-ray spectrometry. These traps may be also induced by the fast growth of CdS nanocrystals in this matrix or laser exposure during PL measurements. These CdS-doped glasses with an intense absorption in the UV–Vis region and a large emission band with long lifetime and a large Stokes-shift are adequate for luminescent solar concentrators, photocatalytic applications and solid-state lasers. [ABSTRACT FROM AUTHOR]

This study presents the effect of YBaCuO (Y211) nanoparticle doping on critical current density and critical temperature of YBaCu O (YBCO) superconductor. Y211 nanoparticles with different particle sizes ranging from 34 to 455 nm were synthesized by a sol-gel method, then doped into the YBCO superconductor by 0.5, 1, and 2 wt.%. Samples were characterized using X-ray diffraction and scanning electron microscope measurements. The standard four-probe technique was used to measure the critical current density at 77 K. The results showed that in the all-doped samples, critical current density was higher than that of the pure sample. It was found that in the samples containing 1 and 2 wt.% of Y211 nanoparticles, by increasing the size of nanoparticles, the J was increased, but in samples containing 0.5 wt.%, the J decreased. The maximum critical current density of 64 A/cm was obtained for the samples doped with 2 wt.% of 455 nm Y211 nanoparticles. Also, it was observed that the critical temperature slightly decreased with nanoparticle doping. [ABSTRACT FROM AUTHOR]

We report a fluorescent carbon nanoparticle (FCN)-based lateral flow biosensor for ultrasensitive detection of DNA. Fluorescent carbon nanoparticle with a diameter of around 15 nm was used as a tag to label a detection DNA probe, which was complementary with the part of target DNA. A capture DNA probe was immobilized on the test zone of the lateral flow biosensor. Sandwich-type hybridization reactions among the FCN-labeled DNA probe, target DNA and capture DNA probe were performed on the lateral flow biosensor. In the presence of target DNA, FCNs were captured on the test zone of the biosensor and the fluorescent intensity of the captured FCNs was measured with a portable fluorescent reader. After systematic optimizations of experimental parameters (the components of running buffers, the concentration of detection DNA probe used in the preparation of FCN-DNA conjugates, the amount of FCN-DNA dispensed on the conjugate pad and the dispensing cycles of the capture DNA probes on the test-zone), the biosensor could detect a minimum concentration of 0.4 fM DNA. This study provides a rapid and low-cost approach for DNA detection with high sensitivity, showing great promise for clinical application and biomedical diagnosis. [ABSTRACT FROM AUTHOR]

Silica-coated magnetic NiFeO nanoparticles-supported H[NaPWO] (NiFeO@SiO-H[NaPWO]) was successfully synthesized and shown to be a versatile and highly efficient heterogeneous catalyst for one-pot multicomponent synthesis of 1,4-dihydropyridine derivatives under solvent-free condition. The synthesized catalyst can be magnetically recovered and reused four times without significant loss in catalytic efficiency. [ABSTRACT FROM AUTHOR]

A multifunctional nanobiomaterial has been developed by deliberately combining functions of superparamagnetism, fluorescence, and axonal tracing into one material. Superparamagnetic iron oxide nanoparticles were first synthesized and coated with a silica layer to prevent emission quenching through core-dye interactions; a fluorescent molecule, fluorescein isothiocyanate, was doped inside second layer of silica shell to improve photo-stability and to enable further thiol functionalization. Subsequently, biotinylated dextran amine, a sensitive axonal tracing reagent, was immobilized on the thiol-functionalized nanoparticle surfaces. The resulting nanoparticles were characterized by transmission electron microscopy, dynamic light scattering, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis spectroscopy, magnetic resonance imaging and fluorescence confocal microscopy. In vitro cell experiments using both undifferentiated and differentiated Neuro-2a cells showed that the cells were able to take up the nanoparticles intracellularly and that the nanoparticles showed good biocompatibilities. In summary, this new material demonstrated promising performances for both optical and magnetic resonance imaging modalities, suggesting its promising potentials in applications such as in non-invasive imaging, particularly in neuronal tracing. Graphical abstract: [ABSTRACT FROM AUTHOR]

The self-assembly of organic molecules is versatile to prepare various nanostructures. In this work, a new fluorescent molecules containing triple-BODIPY ( TBDP ) were synthesized, which can self-assemble into stable nanoparticles ( TBDP-NPs ) by nanoprecipitation procedure. The byproducts containing dual-BODIPY units also could form nanoparticles, which possess relatively poor stability in aqueous media. Interestingly, the fluorescent nanoparticles emit different fluorescence at 566 nm and 683 nm under excitation of 500 nm, and the emission at 683 nm can be used as sensor for validating the self-assembly behaviors. The TBDP-NPs excellent cytocompatibliy, and could be internalized by cancer cells for living cell imaging. This work highlights the great potential of self-assembling of organic molecules for functional nanomaterials. [ABSTRACT FROM AUTHOR]

We report on a novel type of spaser which is based on the nonlinear optical Raman gain rather than stimulated emission. It consists of a plasmonic nanoantenna as the cavity and a highly Raman-active diamond nanoparticle as the gain medium. Ultrasmall mode volume accompanied by strong field enhancement and high Raman gain enable Raman spaser-based nanolasing. By using the model describing the oscillation of Raman mode in micro/nanocavity and the calculations for plasmonic nanocavity characteristics, we theoretically study the dependency of spasing threshold on the structural parameters. We believe that our work will trigger the extensive studies of nonlinear optical spasers. [ABSTRACT FROM AUTHOR]

Molecular imaging, where the location of molecules or nanoscale constructs can be tracked in the body to report on disease or biochemical processes, is rapidly expanding to include combined modality or multimodal imaging. No single imaging technique can offer the optimum combination of properties (e.g. resolution, sensitivity, cost, availability). The rapid technological advances in hardware to scan patients, and software to process and fuse images, are pushing the boundaries of novel medical imaging approaches, and hand-in-hand with this is the requirement for advanced and specific multimodal imaging agents. These agents can be detected using a selection from radioisotope, magnetic resonance and optical imaging, among others. Nanoparticles offer great scope in this area as they lend themselves, via facile modification procedures, to act as multifunctional constructs. They have relevance as therapeutics and drug delivery agents that can be tracked by molecular imaging techniques with the particular development of applications in optically guided surgery and as radiosensitizers. There has been a huge amount of research work to produce nanoconstructs for imaging, and the parameters for successful clinical translation and validation of therapeutic applications are now becoming much better understood. It is an exciting time of progress for these agents as their potential is closer to being realized with translation into the clinic. The coming 5-10 years will be critical, aswe will see if the predicted improvement in clinical outcomes becomes a reality. Some of the latest advances in combination modality agents are selected and the progression pathway to clinical trials analysed. [ABSTRACT FROM AUTHOR]

Environmental-friendly continuous process of manufacturing structure-controlled carbon black (CB) nanoparticles has been developed by the combination of advantages of alternative-current (AC) gliding arc plasma and direct-current (DC) arc discharge plasma. In this process, methane was first decomposed in the low temperature AC gliding arc plasma and then further thermally pyrolyzed in the DC arc discharge plasma area. CB was generated in the AC arc plasma area and then continued to grow or surface modified by DC arc plasma according to different arc positions, which was determined by the operating gas flow rate. The effects of AC arc and DC arc on the yield, size, morphology and structure of particles have been investigated. The connection of AC and DC plasma areas might cause totally different growth process of nanoparticles. Formation mechanism has been discussed based on series of physical characterizations to illustrate the different growth process. The essential properties of CB prepared by plasma have been compared with three kinds of CB purchased, and then all the CB nanoparticles have been blended with acrylonitrile-butadienestyrene/ethylene-propylene-diene monomer composites. Electrical conductivity and mechanical properties as well as the morphology of fracture surface of composites have been characterized. The results indicate that CB prepared from AC plasma process shows excellent mechanical reinforcement and CB from AC + DC plasma process owns outstanding electrical conductivity. [ABSTRACT FROM AUTHOR]

It is necessary to develop rapid, simple and accurate detection method for Escherichia coli ( E. coli ) due to its widely distributed pathogenic bacteria. Herein, we prepared AgBr nanoparticles (NPs) anchored 3D nitrogen-doped graphene hydrogel (3DNGH) nanocomposites with an exceptionally large accessible surface by a simple hydrothermal approach. The as-prepared 3DNGH porous nanocomposite not only showed better conductivity than that of 3D graphene due to introducing nitrogen element into graphene framework, but also provided a high loading volume for immobilizing luminol. Meanwhile the anchored AgBr NPs served as the catalyst can effectively enhance the ECL behavior of luminol. And the resulting luminol/AgBr/3DNGH exhibited more excellent ECL performances, which was about 2, 3, 8 times enhanced respectively, comparing to luminol/AgBr/3DGH, luminol/3DNGH and luminol/AgBr/2DNG. Further, the multifunctional nanoarchitecture was used as the all-solid-state ECL platform for fabricating Escherichia coli aptasensors via glutaraldehyde as crosslinking agent between amine-functionalized E. coli aptamer and luminol/AgBr/3DNGH. Based on the steric hindrance mechanism that E.coli can significantly decrease the ECL intensity, the proposed aptasensor displayed a linear response for E.coli in the range from 0.5 to 500 cfu/mL with an extremely low detection limit of 0.17 cfu/mL (S/N). In addition, this ECL aptasensor possessed great advantages including the simple operation process, low-cost and sensitivity, which provided a promising approach for the E.coli detection in biomedical, food detection and environmental analysis. [ABSTRACT FROM AUTHOR]

A broad general interest in the process of affecting the energetic deposition of flying nanoparticles has prompted a new opportunity to consider the medium-energy region in which the nanoparticles maintain their integrity and must respond to the energetic shock caused by collisions. We herein report our experimental results on the structural transition of the carbon nanoparticles induced by such energetic collisions. The beam energy was varied from 0 keV to 30 keV for a nanoparticle with over 5000 carbon atoms. Electron energy loss spectroscopy, X-ray photoemission spectroscopy, and Raman spectroscopy were carried out on the samples using a series of beam energies. These tests revealed that some graphitic sheets were formed at the higher beam energy while the sp3 ratio was unexpectedly higher for a medium beam energy. [ABSTRACT FROM AUTHOR]

Upconversion luminescent nanomaterials have great outlook towards imaging applications. These materials have high chemical and thermal stability, low auto fluorescence, high photo stability and IR excitation does not cause photo damage to living cells and penetrate deeply into tissue. Most of the reported nanoparticles are synthesized through chemical methods in which surface modification is needed for dispersing nanoparticles in water. In this paper we report clean and simple synthesis of upconversion luminescent yttrium oxyfluoride (YOF) nanoparticles through laser ablation in deionized water. YOF:Er 3+ , Yb 3+ pellets were used for ablation. Er 3+ is the emission centre Yb 3+ is the sensitizer. Obtained colloidal solution is transparent to day light and showing red emission on exciting with 980 nm IR laser. By controlling ablation parameters particles of size less than 10 nm dispersed uniformly in water can be obtained through this surfactant free method. The synthesized nanoparticles can be used for cell imaging. [ABSTRACT FROM AUTHOR]

Two copper nanoclusters (NCs) stabilized by l -cysteine and glutathione have been reported. The nanoparticles with ultrafine size had excellent water solubility and exhibited green or red emission respectively. Particularly, the two copper clusters were found to be responsive to the presence of tetracycline (TC) and on-off quenching effects were achieved. After incubation, the cell staining and target-detection features could be still effective in two adherent live cells. The nanocluster showed very low cytotoxicity and excellent biological compatibility. Accordingly, the special photophysical properties of copper NCs will be attractive for various potential applications such as bio-sensing and medical diagnosis. [ABSTRACT FROM AUTHOR]

Semiconductor nanophosphors have smart technological applications in optoelectronic devices and in nanomedicine. Here we report the synthesis of Calcium sulfide nanophosphors by wet chemical method using Triethanolamine (TEOA) as capping agent. The structural characterization of the prepared nanoparticles was done using X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The XRD pattern confirmed the cubic CaS phase with an average grain size of 21 nm of the formed samples. From TEM images, the TEOA capped nanoparticles were found to have a spherical morphology with diameter in the range 5–15 nm. The optical studies of the capped nanoparticles were carried out using Photoluminescence spectroscopy and UV–vis absorption spectroscopy. We obtained a highly intense blue emission on exciting the TEOA capped nanoparticles at 318 nm which was found to be greater than the luminescence intensity of uncapped CaS nanoparticles. The optical band gap of the capped nanoparticles was estimated from the Diffuse Reflectance Spectra and an increase in bandgap was observed which can be explained on the basis of quantum size effect. Thermogravimetric analysis and Fourier Transform Infrared Spectra analysis confirmed the presence of capping agent in the synthesized CaS nanoparticles. [ABSTRACT FROM AUTHOR]

Copper ions (Cu 2+ ) play a key role in ecosystems and human health, however, the copper pollution caused by the excessive use of copper has become one of the main problems of modern world. In this paper, a facile method was developed to construct a multifunctional nanoprobe for Cu 2+ detection by combining the mesoporous silica coated upconversion nanoparticles (UCNPs) with rhodamine B derivative. β-NaYF 4 :Yb,Er@NaGdF 4 , which could achieve upconversion luminescence (UCL)/magnetic resonance imaging (MRI) dual-mode imaging, was prepared first and then coated with mesoporous silica to form the hydrophilic nanospheres. Subsequently, a rhodamine B derivative DFPP-RhB (denoted as P) was grafted to the mesoporous silica to construct the final multifunctional nanoprobe (denoted as UCNPs@mSiO 2 -P). In this nanoprobe, the mesoporous silica coated NaYF 4 :Yb,Er@NaGdF 4 served as the energy donor, while the rhodamine B derivative P was used as the energy acceptor, resulting in an efficient luminescence resonance energy transfer (LRET) system. The UCNPs@mSiO 2 -P nanoprobe shows high selectivity and sensitivity in detecting of Cu 2+ . In addition, the T 1 -weighted MRI measured in aqueous solutions reveals that the positive enhancement signals were obtained with increasing of Gd 3+ concentrations. This method demonstrates a simple but fascinating strategy to combine the metal ion sensing and multimodal imaging. [ABSTRACT FROM AUTHOR]

Cerium doped zinc oxide (2 at. %) aerogels were synthesized in supercritical methanol and different supercritical mixture solvents (methanol-acetone and methanol-ethanol). The as-elaborated samples were analyzed without any additional heat or chemical treatments by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), optical absorption, photoluminescence (PL) and TGA techniques. The XRD results show that drying in solvents mixture enhances the crystalline quality and acts as a compression agent by exerting stress on the lattice parameters. SEM images demonstrate that the agglomeration rate of aerogel particles decreases when solvents mixture is used. TGA measurements showed the high purity of the samples. FTIR results showed a shift of Zn O bond indicating that supercritical solvent influences the number of Ce O Zn bonds at the surface of the crystallites. UV–vis characterization demonstrates that a band-to-band transition (3.34 eV) is observed only in the spectrum of the aerogel synthesized in supercritical acetone. The photoluminescence (PL) spectra exhibited different optical properties of the aerogels in violet-blue-green wavelengths region (350–530 nm). A blue-green emission located at 485 nm is observed only in methanol and acetone. The intensity of this band is sensitive to the supercritical organic solvent. [ABSTRACT FROM AUTHOR]

In this paper we present an experimental technique and a novel colourimetric image analysis algorithm to economically evaluate particle residence times within regions of batch granulators for use in compartmental population balance models. Residence times are extracted using a simple mixing model in conjunction with colourimetric data. The technique is applied to the mixing of wet coloured granules (binary and ternary systems) in a laboratory scale mixer. The resulting particle concentration evolutions were in qualitative agreement with those from the mixing model. It was seen that the algorithm was most stable in the case of the binary colour experiments. Lastly, simulations using the Discrete Element Method (DEM) were also performed to further validate the assumptions made in the analysis of the experimental results. Particle concentrations from the simulations showed the same trends as the experiment and highlighted the importance of particle size distributions on the DEM residence times. [ABSTRACT FROM AUTHOR]

Biodegradable calcium carbonate carriers are a promising and safe nanoparticle platform which might enable various applications as an engineered nanomaterial in health care, food and cosmetics. However, engineered nanoparticles can exhibit new forms of toxicity that must be carefully evaluated before being widely adopted in consumer products or novel drug delivery systems. To this end, we studied four common calcium carbonate particle systems (calcite nanoparticles, amorphous sub-micrometer and vaterite sub-micrometer and micrometer particles) and compared their behavior in biological medium and in cell culture experiments. The thermodynamically stable calcite phase is shown to maintain its morphological features as no phase transformation occurs. Size- and time-dependent phase transformation of the less stable vaterite particles are observed within 96 h in cell medium. The protein serum albumin can be an effective inhibitor of phase-transition and it is shown to improve colloidal stability. The impact of the biological environment goes beyond protein-corona formation, as we observed rapid dissolution of amorphous particles in high ionic strength cell medium, but not in Millipore water. Cellular responses of human osteoblasts against CaCO 3 particles indicate that increased intracellular calcium ions improve viability and that particle internalization is not size-dependent. Useful insights for designing CaCO 3 -based delivery systems are provided and also corroborate to the idea that intrinsic material properties as well as environmental conditions are of relevance for the successful implementation of dispersed CaCO 3 particles in drug delivery systems and in other applications. [ABSTRACT FROM AUTHOR]

The main binding phases of calcium aluminate cement (CAC) concrete, CaO·Al2O3·10H2O (CAH10) and 2CaO·Al2O3·8H2O (C2AH8), slowly convert to 3CaO·Al2O3·6H2O (C3AH6) and Al(OH)3 (AH3). This reaction significantly speeds up at a temperature higher than ∼30°C, and over time leads to significant strength loss in CAC concrete. Because of the lack of direct evidence that simultaneously probes morphological and chemical/crystallographic information, intense debate remains whether the conversion is generated by a solid-state or through-solution reaction. The conversion of CAH10 at an elevated temperature is studied herein using synchrotron-radiation-based X-ray spectromicroscopy capable of acquiring near edge X-ray absorption fine structure data and ptychographic images with a resolution of ∼15 nm. We show that, when stored at 60°C, CAH10 first converts to C2AH8 by solid-state decomposition, followed by the through-solution formation of C3AH6. The C3AH6 crystallizes from both the relics of dissolved C2AH8 and from the surface of existing C3AH6 crystals. The solid-state decomposition of CAH10 occurs in multiple sites inside the CAH10 crystals; the spatial range of each decomposition site spans a few tens of nanometers, which overcomes the kinetics barrier of ion transportation in the solid-state. Our work provides the first nanoscale crystal-chemical evidence to explain the microstructure evolution of converted CAC concrete. [ABSTRACT FROM AUTHOR]

Electrochemical promotion of catalysis (EPOC) is a general phenomenon of modifying the catalytic activity of a metal or metal oxide in contact with a solid electrolyte by means of current or potential application. In this work, the free-standing (unsupported) platinum and ruthenium oxide nanoparticles (NPs) (2 nm average size) in contact with yttria-stabilized zirconia (YSZ) solid-electrolyte were electrochemically promoted under galvanostatic and potentiostatic conditions for ethylene oxidation reaction. The enhancement ratio of 1.8 and 1.5 was obtained for Pt and RuO 2 NPs, respectively in potentiostatic conditions at 350 °C. The apparent Faradaic efficiency, Λ , was as high as 400 at 250 °C and decreased as the reaction temperature increased. Similar degrees of promotion were achieved under open circuit by dispersing nanoparticles on CeO 2 , TiO 2 and YSZ supports (1 wt.% metal loading). The results showed the functional equivalence of EPOC and MSI with Pt and RuO 2 NPs. This finding is of considerable value for elucidation of the mechanism of MSI and EPOC, as well as for potential practical implementation of EPOC in industrial catalytic processes that use highly dispersed nanoparticle catalysts. [ABSTRACT FROM AUTHOR]

A magnetic graphitic carbon nitride (g-CN-SnFeO) modified with N-[3-(trimethoxysilyl)propyl] ethylenediamine (TPED) was synthesized and utilized as a nanoadsorbent for the ultrasound-assisted magnetic dispersive microsolid-phase extraction of the ions Pb(II) and Cd(II) from foodstuff. The presence of the TPED group on the nanoadsorbent results in a superior uptake of the analytes via complexation. The grafting of TPED on the adsorbent was corroborated by FT-IR, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy elemental analysis, and vibrating sample magnetometry. The adsorption and desorption steps were optimized via the central composite experimental design. Following desorption, the ions were quantified via micro-sampling atomic absorption spectrometry. Under optimized conditions, the limits of detection (LODs) are 0.6 and 0.1 μg L for for Pb(II) and Cd(II), respectively, the linear dynamic ranges extend from 2.0 to 600.0 μg L, and the relative standard deviations (for n = 5) are 3.6 and 4.6%. Notably, only 5.0 mg of the nanoadsorbent are needed, and it can be reused up to 5 times at extraction recoveries of >99%. [ABSTRACT FROM AUTHOR]

Amidosulfonic acid-capped silver nanoparticles (ASA-AgNPs) were synthesized and characterized by UV-Vis, FTIR and TEM methods. It was found that in the presence of lamotrigine (LTG) in aqueous solution, the ASA-AgNPs undergo a visual color change from yellow to red to violet. This corresponds to absorption peaks at 390, 450 and 620 nm depending on the concentration of LTG. TEM images confirmed that the observed changes are as a result of the LTG-induced aggregation of nanoparticles. A linear relationship exists between LTG concentration and the absorbance ratios at 390 and 450 nm. The limit of detection is 5 ng·mL. The method was applied successfully to the determination of LTG in exhaled breath condensate of epileptic patients' receiving LTG. [ABSTRACT FROM AUTHOR]

Aqueous acrylamide gels can be used to provide dynamic nuclear polarization (DNP) NMR signal enhancements of around 200 at 9.4 T and 100 K. The enhancements are shown to increase with crosslinker concentration and low concentrations of the AMUPol biradical. This DNP matrix can be used in situations where conventional incipient wetness methods fail, such as to obtain DNP surface enhanced NMR spectra from inorganic nanoparticles. In particular, we obtain 113Cd spectra from CdTe-COOH NPs in minutes. The spectra clearly indicate a highly disordered cadmium-rich surface. [ABSTRACT FROM AUTHOR]

Monoclinic HfO2 nanoparticles with nominal diameters of 9, 30, and 45 nm are characterized using transmission and reflection spectroscopy from the mid- to far-infrared. Phonon modes are identified in the measured spectra and agree with previously reported values in HfO2 thin films and density functional perturbation theory calculations. An anomaly in both reflection and transmission is observed at 556 cm-1that is not attributed to the optical phonon modes. Numerical models predict a localized surface phonon polariton mode near this frequency, and we attribute the anomaly to coupling to this surface mode. The results of this work suggest that HfO2 nanoparticles could enable engineered optical properties in new mid- and far-infrared materials and devices. [ABSTRACT FROM AUTHOR]

The present study focused on the green synthesis of silver nanoparticles (AgNPs) using Arachis hypogaea (ground nut) root extract for the antibacterial and clinical application. The presence of major phytochemical compounds are found to be 2H-Pyaran,2,5-diethenyltetrahydro, Didodecyl phthalate, Decanoic acid, Tetradecanoic acid, Bis(2-ethylhexyl) phthalate, Dodecanoic acid, Phosphonic acid, 2-(4-Methoxyphenyl)-5-(4-methoxynaphthyl) thiophene and Methyl 2-(N-Benzylimino)-4-chloro-3,3-dimethylbutanoate by GC-MS. Nanoparticles synthesis is confirmed by UV-Vis analysis by observing the maximum absorption spectrum at 450 nm. XRD and SEM-EDX results reveals the synthesized nanoparticles are cubic crystalline with agglomerated particles of silver oxide with biomolecules present around it. TEM images clearly shows that the biosynthesized nanoparticles are mostly spherical and irregular shaped with an average particles size of 30 nm. Highest susceptibility pattern of silver nanoparticle against Enterococcus sp. (35 ± 0.4 mm) which followed by Pseudomonas sp. (33 mm) and Staphylococcus aureus (29 mm). Green synthesized nanoparticles are coated over the commercially available clinical band aid cloth by dip coating method. Silver nanoparticle incorporated band aid cloth showed good antibacterial activity against the harmful bacteria which usually cause infection and interfere during wound healing. Our findings revealed that green nanoparticle has a good antibacterial action against harmful bacteria and showed good response for efficient clinical application. [ABSTRACT FROM AUTHOR]

It is of vital importance to theoretically understand unique nanoparticle size-tunable and excitation wavelength-dependent multiple optical properties in organic nanoparticles. In this work, we proposed a theoretical protocol to calculate the optical spectrum of the organic nanoparticles, which combines molecular dynamics (MD) simulation, the quantum mechanics/molecular mechanics (QM/MM) approach, and vibronic-coupled Frenkel exciton spectrum theory. By using the protocol, we explored the relationship between intramolecular structure distortion, irregular intermolecular packing, and optical spectra in α-sexithiophene nanoparticles. Two representative clusters cutting from the simulated amorphous nanoparticle were investigated and found to exhibit a blue shift for absorption and emission spectra compared to the solution, which is totally different from the blue-shifted absorption and red-shifted emission in crystal. For the cluster with distorted monomer and disordered packing, the blue shift results from the higher excitation energy and larger vibronic coupling of low-frequency vibration modes, while for the cluster with planar monomer and ordered packing, the blue shift is induced by the synergism of vibronic coupling and excitonic coupling. Strikingly, the superposition of the spectra of two clusters reproduces the experimental spectra and well explains the unusual blue-shifted emission observed for α-sexithiophene nanoparticles. Our theoretical protocol is general and applicable to other organic nanoparticles, thus aiding the rational design of high-quality organic nanoparticles. [ABSTRACT FROM AUTHOR]

Assembly of anisotropic nanoparticles on polymeric templates has attracted much attention recently because of the potential useful applications. In this work, 3D electrospun nanofiber membrane is used as template for the assembly of ex situ synthesized palladium nanocubes. The assembly process is achieved by simple immersion step, in which the electrostatic assembly of the nanocubes occurs. The dense nanocubes on the nanofibers as well as the fibrous nanostructure render the nanocomposite membrane excellent catalytic activity. Moreover, the catalytic membrane can be recycled for at least six times, which makes it possible for practical usage. [ABSTRACT FROM AUTHOR]

A durable fluorine-free polyethersulfone (PES) superhydrophobic composite coating with excellent wear-resistant and anti-corrosion properties has been successfully fabricated by combining sol-gel and spray technology. The robust micro/nano-structures of the prepared surface were established by introducing binary montmorillonite-silica (MMT-SiO 2 ) assembled composite particles, which were formed by in-situ growth of SiO 2 on MMT surfaces via sol-gel. Combined with the low surface energy of amino silicon oil (APDMS), the fluorine-free superhydrophoic PES coating was obtained with high water contact angle 156.1 ± 1.1° and low sliding angle 4.8 ± 0.7°. The anti-wear of the final PES/APDMS/MMT-SiO 2 superhydrophobic coating can reach up to 60,100 cycles, which is outdistancing the pure PES coating (6800 cycles) and the PES/MMT/SiO 2 coating prepared by simple physical mixture (18,200 cycles). The enhanced wear resistance property can be mainly attributed to the lubrication performance of APDMS and stable interface bonding force between the MMT surface and SiO 2 . Simultaneously, potentiodynamic polarization curves and electrochemical impedance spectroscopy exhibited the outstanding anti-corrosion property of PES/APDMS/MMT-SiO 2 composite coating, with low corrosion current (1.6 × 10 −10 A/cm 2 ) and high protection efficiency (99.999%) even after 30 d immersion process. These test results show that this durable superhydrophobic PES composite coating can be hopefully to provide the possibility of industrial application. [ABSTRACT FROM AUTHOR]

A novel polyvinylidene fluoride (PVDF) ultrafiltration membrane with photocatalytic and antibacterial properties was prepared by phase inversion. The in situ formed silver (Ag) nanoparticles were immobilized with titanium dioxide (TiO) nanoparticles. And the modified PVDF membranes were fabricated by adding Ag-TiO into the casting solution. Results showed that the surface contamination of membrane can be degraded effectively by photocatalysis method. Compared with the pristine membrane, the hydrophilicity of modified membrane was improved. Besides, the modified membrane had an excellent antibacterial property. Therefore, the novel Ag-TiO-PVDF membrane has a very promising application perspective. [ABSTRACT FROM AUTHOR]

The knowledge about how CO occupies and detaches from specific surface sites on well-structured Pt surfaces provides outstanding information on both dynamics/mobility of COads and oxidation of this molecule under electrochemical conditions. This work reports how the potentiostatic growth of different coverage CO adlayers evolves with time on both cubic and octahedral Pt nanoparticles in acidic medium. Data suggest that during the growth of the CO adlayer, COads molecules slightly shift toward low coordination sites only on octahedral Pt nanoparticles, so that these undercoordinated sites are the first filled on octahedral Pt nanoparticles. Conversely, on cubic Pt nanoparticles, adsorbed CO behaves as an immobile species, and low coordinated sites as well as (100) terraces are apparently filled uniformly and simultaneously. However, once the adlayer is complete, irrespectively of whether the CO is oxidized in a single step or in a sequence of different potential steps, results suggest that COads behaves as an immobile species during its oxidation on both octahedral and cubic Pt nanoparticles. [ABSTRACT FROM AUTHOR]

Magnetic core–shell nanoparticles (CSNs) have potential applications in spintronic devices, drug delivery systems, and magnetic random access memory. By use of our hydrothermal nano-phase epitaxy method, we have accomplished synthesis of novel, well-ordered α-Cr2O3@α-Mn0.35Cr1.65O2.94 inverted CSNs. XRD and TEM analyses show a core–shell structure with corundum phase throughout the core and shell with a minimal amount of interface defects. TEM-EDX and XPS data show Mn having the +2 oxidation state in the shell of the CSNs. Magnetization measurements at 5 K show a weak coercivity (HC) value of 8 Oe and an exchange bias field (HE) of 293 Oe. Ab initio calculations show that Mn incorporation in α-Cr2O3 results in narrowing of the energy band gap, substantiated by UV–Vis measurements, and half metallic behavior in case of Mn(III) substitution. Our calculations substantiate that Mn substitution in α-Cr2O3 results in a combination of antiferromagnetic and weak ferrimagnetic character of our CSNs. [ABSTRACT FROM PUBLISHER]

A synthesis methodology is demonstrated to produce MoS2 nanoparticles with an expanded atomic lamellar structure that are ideal for Faradaic-based capacitive charge storage. While much of the work on MoS2 focuses on the high capacity conversion reaction, that process is prone to poor reversibility. The pseudocapacitive intercalation-based charge storage reaction of MoS2 is investigated, which is extremely fast and highly reversible. A major challenge in the field of pseudocapacitive-based energy storage is the development of thick electrodes from nanostructured materials that can sustain the fast inherent kinetics of the active nanocrystalline material. Here a composite electrode comprised of a poly(acrylic acid) binder, carbon fibers, and carbon black additives is utilized. These electrodes deliver a specific capacity of 90 mAh g−1 in less than 20 s and can be cycled 3000 times while retaining over 80% of the original capacity. Quantitative kinetic analysis indicates that over 80% of the charge storage in these MoS2 nanocrystals is pseudocapacitive. Asymmetric full cell devices utilizing a MoS2 nanocrystal-based electrode and an activated carbon electrode achieve a maximum power density of 5.3 kW kg−1 (with 6 Wh kg−1 energy density) and a maximum energy density of 37 Wh kg−1 (with 74 W kg−1power density). [ABSTRACT FROM AUTHOR]

Dielectric nanoparticles can demonstrate a strong forward scattering at visible and near-infrared wavelengths due to the interaction of optically induced electric and magnetic dipolar resonances. For a spherical nanoparticle, the first Kerker's condition within dipole approximation can be realized, where backward scattering can reach zero. However, for this type of dielectric sphere, maximum forward scattering without backward scattering cannot be realized by modulating the refractive index and particle size of this nanoparticle. In this paper, we have demonstrated that a larger directional forward scattering than the traditional spherical nanoparticle can be obtained by using the ellipsoidal nanoparticle, due to the overlapping electric and magnetic dipolar modes. For the oblate ellipsoid with a determined refractive index, there is an optimum shape for generating the suppressed backward scattering along with the enhanced forward scattering at the resonant wavelength, where the electric and magnetic dipolar modes overlap with each other. For the prolate ellipsoid, there also exist the overlapping electric and magnetic dipolar modes at the resonant wavelength of total scattering, which have much higher forward scattering than those for both oblate ellipsoid and sphere, due to the existence of the higher multipolar modes. Furthermore, we have also demonstrated the realization of the dimensional tailoring in order to make the strong forward scattering shift to the desired wavelength. [ABSTRACT FROM AUTHOR]

Two shapes of TiO2 nanomaterial will largely affect the catalytic activity. TiO2 nanoparticles (NPs) and TiO2 nanofibers (NFs) were used to investigate the effect of shape on catalytic activities and get the optimum shape of catalysis. Electrochemical behaviors of two modified electrodes by TiO2 nanomaterial were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. Various electrochemical parameters such as electrode surface area and electron-transfer rate constant were also studied and calculated in the aqueous solution. Results showed that the response of NF is better than NP for electrooxidation of hydroquinone (HQ). The different electrochemical response of TiO2 is related to the various morphological structures, so controlling the shape and structure of nanomaterial is very important factor which is because of the powerful correlation between these parameters and their optical, catalytic and electrical properties. [ABSTRACT FROM AUTHOR]

Nanocatalysis using metal nanoparticles constitutes one of the emerging technologies for destructive oxidation of organics such as dyes. This paper deals with the degradation of acid red-26 (AR-26), an azo dye by hexacyanoferrate (abbreviated as HCF) (III) using iridium nanoparticles. UV-vis spectroscopy has been employed to obtain the details of the oxidative degradation of the selected dye. The effect of various operational parameters such as HCF(III) concentration, pH, initial dye concentration, catalyst and temperature was investigated systematically at the λmax, 507 nm, of the reaction mixture. Degradation kinetics follows the first order kinetic model with respect to AR-26 and Ir nano concentrations, while with respect to the HCF(III) concentration reaction it follows first order kinetics at lower concentrations, tending towards zero order at higher concentrations. Thermodynamic parameters have been calculated by studying the reaction rate at four different temperatures. The UV-vis, high performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LCMS) analysis of degradation products showed the formation of carboxylic acid and substituted carboxylic acids as major degradation products, which are simple and less hazardous compounds. The big advantage of the present method is the recovery and reuse of iridium nanoparticles. Moreover, turnover frequencies for each catalytic cycle have been determined, indicating the long life span of Ir nanoparticles. Thus, the finding is a novel and highly economical alternative for environmental safety against pollution by dyes, and extendable for other contaminants as well. [ABSTRACT FROM AUTHOR]

We propose a method for obtaining a fluorescence tomographic image for visualization and diagnosis of tissues of a living organism. The method is based on the excitation of the luminescence of multicolor upconverting nanoparticles localized in the depth of the biological tissue or a phantom imitating it by IR light. By recording the changes in the shape of the spectrum of the intensity of luminescence radiation from luminescent nanoparticles on the surface of the tissue, it is possible to obtain information about the depth of their occurrence. To implement this approach, upconverting nanoparticles were synthesized on the base of β-NaYF4 crystal matrix doped with rare-earth elements Yb3+, Er3+, and Tm3+. The luminescence spectra of the produced nanoparticles upon excitation at a wavelength of 980 nm contain three narrow bands with maxima at wavelengths 540, 655, and 800 nm. [ABSTRACT FROM AUTHOR]

A continuous flow device to characterize the growth of nanometer particles was assembled. In-situ millisecond or second-order time-resolved small angle x-ray scattering and x-ray absorption spectroscopy was performed using this device at the Beijing Synchrotron Radiation Facility. The time resolution was adjusted from 10 ms to 1.0 s by changing the flow rate of the solution. The temperature was variable from 5–95°C. Custom-designed pulse eliminators were employed to eliminate adverse pump fluctuations and improve the quality of measurements. The system was used to characterize zinc sulfide nanoparticles by small angle x-ray scattering and x-ray absorption spectroscopy. [ABSTRACT FROM PUBLISHER]

A range of catalytic samples made by extractive-pyrolytic method (EPM) and based on nickel and palladium nanoparticles supported on inorganic supports such as activated carbon, silica, alumina and aluminium hydroxide oxide were tested in the reaction of ozone decomposition. Aluminum oxides and oxyhydroxides occur in numerous crystallographic forms which exhibit different surface properties. The properties of the catalysts were confirmed by using various characterization techniques as BET, XRD, EPR and TEM. The EPM method allows small amounts of noble metals with particle size ranging from several nanometers to several tens of nanometers to be affixed onto the surface of the support. It was found that all treated Ni/Pd catalytic samples were active in the ozone decomposition reaction but the maximum conversion degree (more than 90 %) was achieved using aluminium hydroxide oxidesupported Ni/Pd system. [ABSTRACT FROM AUTHOR]

In this study the Mn 1–2x Zr x Fe 2−y Ni y O 4 nanoparticles fabricated by co-precipitation technique were investigated. Thermo-gravimetric analysis (TGA) exhibited the annealing temperature of the nanoparticles ~990 °C. Cubic spinel structure of Mn 1–2x Zr x Fe 2−y Ni y O 4 nanoparticles was confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. Crystallite size was calculated by XRD data and found in the range of 32–58 nm. Photocatalytic activity of Mn 0.92 Zr 0.04 Fe 1.88 Ni 0.12 O 4 /graphene nanocomposites was tested by degrading methylene blue (MB) under visible light irradiation. The MB was almost completely degraded in the presence of Mn 0.92 Zr 0.04 Fe 1.88 Ni 0.12 O 4 -graphene nanocomposites under visible light irradiation. Dielectric parameters were also investigated in the frequency range 1×10 6 –3×10 9 Hz. An overall decrease in the values of dielectric constant, dielectric loss and tangent loss was observed on account of the substitution of Zr and Ni with Mn and Fe cations. [ABSTRACT FROM AUTHOR]