Synthesis,structural, dielectric and magnetic properties of spinel structure of Ca2+ substitute in Cobalt ferrites (Co1−xCaxFe2O4)

Non magnetic material Ca²⁺ as a substitute in Cobalt ferrite (Co_1?xCa_xFe₂O₄x?=?0.00, 0.05, 0.10 & 0.15) is prepared by self auto combustion method. The synthesized samples were carried out for various characterizations such as X-ray diffraction, Field emission scanning electron microscope (FE-SEM), Dielectric measurement and Magnetic property. X-ray diffraction reveals the values of crystalline size, lattice parameter and x-ray density by using the standard formula. The saturation magnetization (M_s) decreases from 63.92 to 43.17 emu/g for x?=?0.00 to 0.15 and the coercivity (H_c) increases gradually from 819.85 to 1312.32?Oe with the increase in Ca²⁺ concentration. The dielectric properties of synthesized nano materials were carried out at room temperature. The dielectric parameters such as tangent loss, Cole–Cole plot (Impedance, Modulus), and AC Conductivity were determined for various Ca²⁺ concentration. The frequency dependent dielectric dispersion behaviour of all the samples can be explained by the Maxwell–Wagner two-layer model along with Koop's phenomenological theory. As a result, Ca²⁺ substituted Cobalt ferrite is enhanced with their dielectric and magnetic property which is suitable for a memory device, recording media application and high frequency device.     

Effect of Ni content on the diffusion-controlled growth of the product phases in the Cu(Ni)–Sn system

A strong influence of Ni content on the diffusion-controlled growth of the (Cu,Ni)₃Sn and (Cu,Ni)₆Sn₅ phases by coupling different Cu(Ni) alloys with Sn in the solid state is reported. The continuous increase in the thickness ratio of (Cu,Ni)₆Sn₅ to (Cu,Ni)₃Sn with the Ni content is explained by combined kinetic and thermodynamic arguments as follows: (i) The integrated interdiffusion coefficient does not change for the (Cu,Ni)₃Sn phase up to 2.5 at.% Ni and decreases drastically for 5 at.% Ni. On the other hand, there is a continuous increase in the integrated interdiffusion coefficient for (Cu,Ni)₆Sn₅ as a function of increasing Ni content. (ii) With the increase in Ni content, driving forces for the diffusion of components increase for both components in both phases but at different rates. However, the magnitude of these changes alone is not large enough to explain the high difference in the observed growth rate of the product phases because of Ni addition. (iv) Kirkendall marker experiments indicate that the Cu₆Sn₅ phase grows by diffusion of both Cu and Sn in the binary case. However, when Ni is added, the growth is by diffusion of Sn only. (v) Also, the observed grain refinement in the Cu₆Sn₅ phase with the addition of Ni suggests that the grain boundary diffusion of Sn may have an important role in the observed changes in the growth rate.     

Cu1.5[Cr(CN)6]⋅6.5H2O nanoparticles: synthesis, characterization, and magnetic properties

We have synthesized nanoparticles of Cu_1.5[Cr(CN)₆]⋅6.5H₂O of varying size by using poly(vinylpyrrolidone) (PVP) as a protecting polymer. The particle size variation has been achieved by varying the amount of the PVP surfactant with the reactants. The prepared nanoparticles have been investigated by using X-ray diffraction, transmission electron microscopy, and direct-current magnetization techniques. The nanoparticles crystallize in a face centred cubic structure (space group: Fm3m). The approximate particle sizes for the three samples are 18, 9, and 5 nm, respectively. Non-PVP nanoparticles (18 nm) show a magnetic ordering temperature of 65 K. A decrease in the magnetic ordering temperature was observed with decreasing particle size. These nanoparticles are magnetically very soft, showing negligibly small values of the coercivity and remanent magnetization. The maximum magnetization and spontaneous magnetization values at 5 K are found to decrease with decreasing particle size. The observed magnetization behaviour of the nanoparticles has been attributed to the increasing surface spin disorder with decreasing particle size.     

Vibrational spectroscopy of Cm-C/Cb-Cb stretching vibrations of copper tetramesityl porphyrin: An algebraic approach

Using Lie algebraic techniques and simpler expressions of the matrix elements of Majorana and Casimir operators given by us, we obtain an effective Hamiltonian operator which conveniently describes stretching vibrations of biomolecules. For a copper tetramesityl porphyrin molecule, the higher excited vibrational levels are calculated by applying the U(2) algebraic approach.     

Co-delivery of doxorubicin and AS1411 aptamer by poly(ethylene glycol)-poly(<Emphasis Type="Italic">β</Emphasis>-amino esters) polymeric micelles for targeted cancer therapy

Recently, targeted drug delivery systems (TDDS) have offered a great potential and benefits towards the anti-tumor drug delivery. In this work, we designed the TDDS using a biocompatible poly(ethylene glycol)-poly(β-amino esters) amphiphilic block copolymer (PEG-PAEs) synthesized by Michael addition polymerization for combinatorial therapy. Further, the chemotherapeutic agents’ doxorubicin (DOX) and AS1411 DNA aptamer (Apt) are encapsulated in the PEG-PAEs NPs (PDANs) for co-delivery therapeutics. PDANs have shown the monodisperse spherical shape, smooth surface with a net positive charge (average diameter—183.1 ± 27.2 nm, zeta potential—31.2 ± 6.3 mV), and good colloidal stability (critical micelle concentration of PEG-PAEs is about 6.3 μg/mL). The pH-sensitive PAEs endowed PDANs both pH-triggered drug release characteristics and enhanced endo/lysosomal escape ability, thus improving the localization and cytotoxicity of DOX. AS1411 Apt conjugated PDANs precisely targeted nucleolin and their uptake correlates to a significant activity enhancement only in tumor cells (MCF-7) but not in normal cells (MCF-10A). Thus, PDANs can be a very promising targeted drug delivery platform for effective breast cancer therapy.

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Graphical abstract Scheme 1 Schematic illustration of the preparation and cellular uptake of targeted co-delivery system

     

Implementation of three reliable methods for finding the exact solutions of (2 + 1) dimensional generalized fractional evolution equations

In this study, we have implemented the three methods namely extended \((G^{\prime}/G)\)-expansion, extended \((1/G^{\prime})\)-expansion and \((G^{\prime}/G,\,\,1/G)\)-expansion methods to determine exact solutions for the (2 + 1) dimensional generalized time–space fractional differential equations. We use Conformable fractional derivative and its properties in this research to convert fractional differential equations to ordinary differential equations with integer order. By using above mentioned methods, three types of traveling wave solutions are successfully obtained which have been expressed by the hyperbolic, trigonometric, and rational function solutions. The considered methods and transformation techniques are efficient and consistent for solving nonlinear time and space-fractional differential equations.     

Rapid communication: $$K_{S}^{0}$$ Production from beryllium target using 120 $$\hbox {GeV}/\hbox {c}$$GeV/c protons beam interactions at the MIPP experiment

We have measured the cross-section for the \(K_{S}^{0}\) production from beryllium target using 120 \(\hbox {GeV}/\hbox {c}\) protons beam interactions at the main injector particle production (MIPP) experiment at Fermilab. The data were collected with target having a thickness of 0.94% of the nuclear interaction length. The \(K_{S}^{0}\) inclusive differential cross-section in bins of momenta is presented covering momentum range from \(0.4\,\hbox {GeV}/\hbox {c}\) to \(30\,\hbox {GeV}/\hbox {c}\). The measured inclusive \(K_{S}^{0}\) production cross-section amounts to \(39.54\pm 1.46\delta _{\mathrm {stat}}\pm 6.97\delta _{\mathrm {syst}}\) mb and the value is compared with the prediction of FLUKA hadron production model.