Investigation of the adsorption behavior of the anti-cancer drug hydroxyurea on the graphene, BN, AlN, and GaN nanosheets and their doped structures via DFT and COSMO calculations

To reduce the direct side effects of chemotherapy, researchers are trying to establish a new approach of a drug-delivery system using nanomaterials. In this study, we investigated graphene and its derivative nanomaterials for their favorable adsorption behavior with the anti-cancer drug hydroxyurea (HU) using DFT calculations. Initially, different pristine and doped graphene and its derivatives were taken into consideration as HU drug carriers. Among them, AlN, GaN, GaN-doped AlN, and AlN-doped GaN nanosheets exhibited favorable adsorption behavior with HU. The HU adsorbed on these four nanosheets with adsorption energies of -0.92, -0.75, -0.83, and -0.69 eV, transferring 0.16, 0.032, 0.108, and 0.230 e charges to the nanosheets, respectively, in air medium. In water solvent media, these four nanosheets interacted with HU by -0.56, -0.45, -0.58, and -0.56 eV by accepting a significant amount of charge of about 0.125, 0.128, 0.192, and 0.126 e from HU. The dipole moment and COSMO analysis also indicated that these nanosheets, except for GaN-doped AlN, show high asymmetricity and solubility in water solvent media due to the increased values of the dipole moment by two or three times after the adsorption of the HU drug. Quantum molecular descriptors also suggest that the sensitivity and reactivity of the nanosheets are enhanced during the interaction with HU. Therefore, these nanosheets can be used as anti-cancer drug carriers.

Magnetic properties, magnetocaloric effect, and critical behaviors in Co1-x Cr x Fe2O4

This research work focuses on the magnetic properties, nature of the magnetic phase transition, magnetocaloric effect, and critical scaling of magnetization of various Co_1−xCr_xFe₂O₄ (x = 0, 0.125, 0.25, 0.375, and 0.5). The tunability of the magnetic moment, exchange interactions, magnetocrystalline anisotropy constant, and microwave frequency using Cr³⁺ content has been found. The nature of the magnetic phase transitions for all the Cr³⁺ concentrations exhibits as second order which has been confirmed from the analysis of critical scaling, universal curve scaling, and scaling analysis of the magnetocaloric effect. The critical exponent analysis for all samples was performed from the modified Arrott-, and Kouvel–Fisher-plots. These critical analyses suggest that x = 0.125, 0.250, and 0.375 samples show reliable results in the magnetocaloric effect with relative cooling power (RCP) values in the range of 128–145 J kg⁻¹. On the other hand, x = 0.00, and 0.500 samples exhibit inconsistent RCP values. The universal curve scaling also confirms the reliability of the magnetocaloric effect of the investigated samples.

Magnetic entropy change as a function of temperature for various Co_1−xCr_xFe₂O₄ at an applied magnetic field of 5 T.

Structural characteristics, cation distribution, and elastic properties of Cr3+ substituted stoichiometric and non-stoichiometric cobalt ferrites

Structural, elastic and cation distribution properties have been investigated on stoichiometric and non-stoichiometric cobalt ferrites. Crystal structure, formation of spinel type ferrite, chemical bonding, cation distribution, and thermal properties of two series of Cr³⁺ substituted stoichiometric and non-stoichiometric various cobalt ferrites with general formula Co_1−xCr_xFe₂O₄ (S1), and Co_1+xCr_xFe_2−xO₄ (S2) were reported. Samples are synthesized by the solid-state reaction technique via planetary ball milling. X-ray diffraction (XRD) analysis confirms the formation of a single phase cubic spinel structure with the space group Fd3̄m. Rietveld refinement results show that Cr occupies both the tetrahedral (A-site) and octahedral sites (B-site). The experimental lattice parameters show increasing trends for both the series with increase of Cr content. The cation–anion vacancies, chemical bonding, and the displacement of oxygen have been evaluated to understand the effect of Cr substitution and how the non-stoichiometry affects the physical and chemical properties of the material. The crystallite size is found to be the decreasing value with an increase of Cr concentration for both series of samples. Specific vibrational modes from the FTIR spectra suggest a gradual change of inversion of the ferrite lattice with the increase of Cr concentration which is also evident from Rietveld refinement data. The elastic properties analysis reveals that the synthesized samples for both series are ductile in nature. The non-stoichiometric structure with excess Co²⁺ may pave a new way to realize the lowering of Curie temperature of ferrite that is expected to improve the magnetocaloric properties.

Structural, elastic and cation distribution properties have been investigated on stoichiometric and non-stoichiometric cobalt ferrites.

Semiconducting to metallic transition with outstanding optoelectronic properties of CsSnCl3 perovskite under pressure

Inorganic non-toxic metal halide perovskites have taken the dominant place in commercialization of the optoelectronic devices. The first principles simulation has been executed with the help of density functional theory to investigate the structural, optical, electronic and mechanical properties of non-toxic CsSnCl3 metal halide under various hydrostatic pressures up to 40 GPa. The analysis of optical functions displays that the absorption edge of CsSnCl3 perovskite is shifted remarkably toward the low energy region (red shift) with enhanced pressure. The absorptivity, conductivity and the value of dielectric constant also increases with the applied pressure. The investigation of mechanical properties reveals CsSnCl3 perovskite is mechanically stable as well as highly ductile and the ductility is increased with increasing pressure. The investigation of electronic properties shows semiconducting to metallic transition occurs in CsSnCl3 under elevated pressure. The Physics behind all these changes under hydrostatic pressure has been analyzed and explained in details within the available Scientific theory.

Narrowing band gap and enhanced visible-light absorption of metal-doped non-toxic CsSnCl3 metal halides for potential optoelectronic applications

Non-toxic (lead-free) inorganic perovskites have seized the leading position in the race for the commercialization of solar cells and other photovoltaic devices.

Correction: Narrowing band gap and enhanced visible-light absorption of metal-doped non-toxic CsSnCl3 metal halides for potential optoelectronic applications

Correction for ‘Narrowing band gap and enhanced visible-light absorption of metal-doped non-toxic CsSnCl₃ metal halides for potential optoelectronic applications’ by Jakiul Islam et al., RSC Adv., 2020, 10, 7817–7827, DOI: 10.1039/C9RA10407K.

Analysis of grain growth, structural and magnetic properties of Li-Ni-Zn ferrite under the influence of sintering temperature

The effect of sintering temperature (T_S) on the structural and magnetic properties of Li_0.15Ni_0.3Zn_0.4Fe_2.15O₄ is investigated and discussed. The sample is synthesized by the sol-gel auto combustion method and sintered at 1373–1573 K for 5 h. Phase identification of the powder sample was performed by using the X-ray diffraction (XRD). The XRD patterns confirmed the formation of single phase cubic spinel structure. The bulk density is correlated with T_S. From the energy-dispersive X-ray spectroscopy study, it is observed that the percentage of the elements in the component phases is well consistent with the nominal composition of the composites. Field Emission Scanning Electron Microscopy showed that the average grain size (D) is increased with increasing T_S. The frequency (100 Hz–120 MHz) dependent complex initial permeability spectra and relative quality factor increased with sintering temperature up to 1523 K then decreased for further increase in temperature. The complex initial permeability has been explained with the help of microstructure, and the redistribution of cations in their sites.

Characterization of local soils and study the migration behavior of radionuclide from disposal site of LILW

Migration behavior of radionuclide is one of the most important factors to be considered for the long-term safety assessment of a radioactive waste disposal facility in a wet geological formation. In the present study, laboratory based column experiments have been carried out to assess the radionuclide migration behavior of ¹³⁷Cs and ⁶⁰Co and to evaluate the retardation factor through a clay soil layers using gamma spectrometry. Investigation was performed for a range of particle sizes and fixed column lengths to determine an appropriate value of migration rate of ¹³⁷Cs and ⁶⁰Co. The distribution pattern of particle size in soil samples were measured by sieved method. Two different particle sizes (≤ 90 μm and mixed size) were used in the column experiments. The migration rate in the clay type soil layer of particle size ≤ 90 μm was found by the order of ⁶⁰Co > ¹³⁷Cs. The maximum migration length of ⁶⁰Co in the soil layer was found to be 0-25 cm, however in the case of ¹³⁷Cs it was found at a maximum length of 0-10 cm. The distribution coefficient of ⁶⁰Co was found nearly same as that of ¹³⁷Cs. The retardation factor was found to be 1.79 and 1.94 for ⁶⁰Co and ¹³⁷Cs, respectively. The experimental breakthrough from this study indicates that the amount of radioactive cesium and cobalt released depends upon the composition of the soils.