Masumeh Rahimkhani | Semnan University (original) (raw)

Papers by Masumeh Rahimkhani

International journal of nanomedicine, 2018

Designer self-assembling peptide nanofibers (SAPNFs) as a novel kind of emerging nanomaterial hav... more Designer self-assembling peptide nanofibers (SAPNFs) as a novel kind of emerging nanomaterial have received more and more attention in the field of nanomedicine in recent years. However, a simple method to monitor and image SAPNFs is still currently absent. RADA16-I, a well-studied ionic complementary peptide was used as a model to check potential amyloid-like staining properties of SAPNFs. Thioflavin-T (ThT) and Congo red (CR) as specific dyes for amyloid-like fibrils were used to stain RADA16-I nanofibers in solution, combined with drugs or cells, or injected in vivo as hydrogels. Fluorescent spectrometry and fluorescent microscopy were used to check ThT-binding property, and polarized light microscopy was used to check CR-staining property. ThT binding with the nanofibers showed enhanced and blue-shifted fluorescence, and specific apple-green birefringence could be observed after the nanofibers were stained with CR. Based on these properties we further showed that ThT-binding flu...

Journal of Magnetism and Magnetic Materials, 2018

Structural, magnetic and ferroelectric properties of polycrystalline BiFeO 3 , Bi 0.9 Dy 0.1 FeO ... more Structural, magnetic and ferroelectric properties of polycrystalline BiFeO 3 , Bi 0.9 Dy 0.1 FeO 3 , BiFe 0.97 Co 0.03 O 3 and Bi 0.9 Dy 0.1 Fe 0.97 Co 0.03 O 3 , which were prepared by solid-state method, have been investigated. The X-ray diffraction (XRD) patterns reveal that all the samples are in single phase and show rhombohedrally distorted perovskite structure with R3c space group. Both XRD and Raman-scattering studies show that Dy and Co co-doped sample has a compressive lattice distortion induced by co-substitution of Dy and Co ions at the A and the B sites, respectively. Dy and Co co-doping favors weak ferromagnetism ordering with evident magnetic hysteresis loop and enhances magnetization values at room temperature. Ferroelectric hysteresis loop for Dy and Co co-doped sample shows the nearly saturated polarization at 40 kV/cm and large remnant polarization. Dy dopant is prominent in the reduced leakage current density, while Co dopant is remarkable in the improved remnant magnetization in Bi 0.9 Dy 0.1 Fe 0.97 Co 0.03 O 3 ceramic. By using a simple model, it was found that the anharmonicity of canted spiral cycloidal spin structure was responsible for the weak ferromagnetism of pure BiFeO 3 , and the enhanced magnetization in Co-doped sample was attributed to the transition from the incommensurate cycloidal spiral spin structure towards the G-type canted collinear antiferromagnetic structure.

Nanostructured As2Ni3O8 samples were synthesized via facile solid-state reactions at 850 and 950 ... more Nanostructured As2Ni3O8 samples were synthesized via facile solid-state reactions at 850 and 950 °C for 8h using As2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and fourier-transform infrared (FTIR) spectroscopy. The rietveld analyses showed that the obtained materials were crystallized well in monoclinic crystal structure with the space group P121/c1. The lattice parameters of the targets were about a = 5.76 Å, b = 9.54 Å and c = 10.18 Å with β = 92.95 °. It was found that nickel nitrate created a highly crystalline and pure As2Ni3O8 structure. However, nickel acetate created the target with lower purity and crystal phase growth; it produced the samples with smaller crystallite sizes. Reaction temperature changing showed that the parameter affected on the crystal growth of the obtained materials. The morphologies of the synthesized materials were studied by field emission scanning...

We report an experimental study of single-phase Bi 0.85Àx La 0.15 Ho x FeO 3 nanoparticles (BLH x... more We report an experimental study of single-phase Bi 0.85Àx La 0.15 Ho x FeO 3 nanoparticles (BLH x FO-NPs) that synthesized by a sol–gel method. The Rietveld refinement of X-ray diffraction pattern of BLH x FO samples indicate a phase transition from rhombohedral (space group R3c) to orthorhombic (space group Pbnm) structure with increasing Ho content. The bond lengths and angles for all samples were determined which supports the magnetic and electrical results. The average particles size of BLH x FO-NPs has been estimated from field emission scanning electron microscopy (FESEM) images and using a standard log-normal distribution equation. The remnant magnetisation in BLH x FO-NPs increase from 0.09 emu/g for x = 0–0.35 emu/g for x = 0.25 sample at 5 K. In order to clarify origin of magnetisation behaviour in BLH x FO-NPs, a systematic investigation has been performed on the magnetisation of all samples. The frequency (f) and composition (x) dependence of relative dielectric constant (e) and dielectric loss (tan d) have been studied for BLH x FO nanoparticles at room temperature. The dielectric properties indicates a local maximum in sample with x = 0.25 while maximum magnetodielectric coefficient occurs in x = 0.35. Simultaneous enhancement in magnetic and dielectric properties can play an important role for the practical applications.

International journal of nanomedicine, 2018

Designer self-assembling peptide nanofibers (SAPNFs) as a novel kind of emerging nanomaterial hav... more Designer self-assembling peptide nanofibers (SAPNFs) as a novel kind of emerging nanomaterial have received more and more attention in the field of nanomedicine in recent years. However, a simple method to monitor and image SAPNFs is still currently absent. RADA16-I, a well-studied ionic complementary peptide was used as a model to check potential amyloid-like staining properties of SAPNFs. Thioflavin-T (ThT) and Congo red (CR) as specific dyes for amyloid-like fibrils were used to stain RADA16-I nanofibers in solution, combined with drugs or cells, or injected in vivo as hydrogels. Fluorescent spectrometry and fluorescent microscopy were used to check ThT-binding property, and polarized light microscopy was used to check CR-staining property. ThT binding with the nanofibers showed enhanced and blue-shifted fluorescence, and specific apple-green birefringence could be observed after the nanofibers were stained with CR. Based on these properties we further showed that ThT-binding flu...

Journal of Magnetism and Magnetic Materials, 2018

Structural, magnetic and ferroelectric properties of polycrystalline BiFeO 3 , Bi 0.9 Dy 0.1 FeO ... more Structural, magnetic and ferroelectric properties of polycrystalline BiFeO 3 , Bi 0.9 Dy 0.1 FeO 3 , BiFe 0.97 Co 0.03 O 3 and Bi 0.9 Dy 0.1 Fe 0.97 Co 0.03 O 3 , which were prepared by solid-state method, have been investigated. The X-ray diffraction (XRD) patterns reveal that all the samples are in single phase and show rhombohedrally distorted perovskite structure with R3c space group. Both XRD and Raman-scattering studies show that Dy and Co co-doped sample has a compressive lattice distortion induced by co-substitution of Dy and Co ions at the A and the B sites, respectively. Dy and Co co-doping favors weak ferromagnetism ordering with evident magnetic hysteresis loop and enhances magnetization values at room temperature. Ferroelectric hysteresis loop for Dy and Co co-doped sample shows the nearly saturated polarization at 40 kV/cm and large remnant polarization. Dy dopant is prominent in the reduced leakage current density, while Co dopant is remarkable in the improved remnant magnetization in Bi 0.9 Dy 0.1 Fe 0.97 Co 0.03 O 3 ceramic. By using a simple model, it was found that the anharmonicity of canted spiral cycloidal spin structure was responsible for the weak ferromagnetism of pure BiFeO 3 , and the enhanced magnetization in Co-doped sample was attributed to the transition from the incommensurate cycloidal spiral spin structure towards the G-type canted collinear antiferromagnetic structure.

Nanostructured As2Ni3O8 samples were synthesized via facile solid-state reactions at 850 and 950 ... more Nanostructured As2Ni3O8 samples were synthesized via facile solid-state reactions at 850 and 950 °C for 8h using As2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and fourier-transform infrared (FTIR) spectroscopy. The rietveld analyses showed that the obtained materials were crystallized well in monoclinic crystal structure with the space group P121/c1. The lattice parameters of the targets were about a = 5.76 Å, b = 9.54 Å and c = 10.18 Å with β = 92.95 °. It was found that nickel nitrate created a highly crystalline and pure As2Ni3O8 structure. However, nickel acetate created the target with lower purity and crystal phase growth; it produced the samples with smaller crystallite sizes. Reaction temperature changing showed that the parameter affected on the crystal growth of the obtained materials. The morphologies of the synthesized materials were studied by field emission scanning...

We report an experimental study of single-phase Bi 0.85Àx La 0.15 Ho x FeO 3 nanoparticles (BLH x... more We report an experimental study of single-phase Bi 0.85Àx La 0.15 Ho x FeO 3 nanoparticles (BLH x FO-NPs) that synthesized by a sol–gel method. The Rietveld refinement of X-ray diffraction pattern of BLH x FO samples indicate a phase transition from rhombohedral (space group R3c) to orthorhombic (space group Pbnm) structure with increasing Ho content. The bond lengths and angles for all samples were determined which supports the magnetic and electrical results. The average particles size of BLH x FO-NPs has been estimated from field emission scanning electron microscopy (FESEM) images and using a standard log-normal distribution equation. The remnant magnetisation in BLH x FO-NPs increase from 0.09 emu/g for x = 0–0.35 emu/g for x = 0.25 sample at 5 K. In order to clarify origin of magnetisation behaviour in BLH x FO-NPs, a systematic investigation has been performed on the magnetisation of all samples. The frequency (f) and composition (x) dependence of relative dielectric constant (e) and dielectric loss (tan d) have been studied for BLH x FO nanoparticles at room temperature. The dielectric properties indicates a local maximum in sample with x = 0.25 while maximum magnetodielectric coefficient occurs in x = 0.35. Simultaneous enhancement in magnetic and dielectric properties can play an important role for the practical applications.