Electrophysical Properties of PMN-PT-Ferrite Ceramic Composites.

Ferroelectromagnetic composites based on (1-x)PMN-(x)PT (PMN-PT) powder and Ni-Zn ferrite powder were obtained and are described in this work. As a ferroelectric component, we used (1-x)PMN-(x)PT solid solution (with x = 0.25, 0.28, 0.31, 0.34, 0.37, 0.40), synthesized using the sol-gel method. As a magnetic component, we used nickel-zinc ferrite, obtained using classic ceramic technology. The six compositions of PMN-PT used have rhombohedral symmetry, tetragonal one and mixture of these phases (morphotropic phase area), depending on x. The final ceramic composite samples were obtained using the classic methods involving the calcination route and pressureless final sintering (densification). The properties of the obtained ceramic composite samples were investigated, including microstructure SEM (scanning electron microscope), dielectric properties, electromechanical properties, and DC (Direct Current) electrical conductivity. Results showed that the microstructures of the PP-F composite samples characterized by larger grains were better crystallized, compared with the microstructures of the PMN-PT ceramic samples. The magnetic properties do not depend on the ferroelectric component of the composite samples, while the insertion of ferrite into the PMN-PT compound reduces the values of remnant and spontaneous polarization, as well as the coercive field. The dielectric measurements also indicated that the magnetic subsystem influences the dielectric properties. The present results show that the PP-F ceramic composite has good dielectric, magnetic, and piezoelectric properties, which predisposes this type of material to specific applications in microelectronics and micromechatronics.

Electrophysical Properties of the PMN⁻PT⁻PS Solid Solution.

The (1 - y) ((1 - x)Pb(Mg1/3Nb2/3)O3⁻xPbTiO3)⁻yPbSnO3 solid solution (PMN⁻PT⁻PS) was obtained and investigated in the present paper. For the analysis of the influence of the PbSnO3 component on the electrophysical parameters, the compositions from the rhombohedral phase, tetragonal phase, and a mixture of these phases were selected. The six compositions of the PMN⁻PT have been obtained using sol⁻gel methods (for values of x equal to 0.25, 0.28, 0.31, 0.34, 0.37, and 0.40). The ceramic samples of the 0.9(PMN⁻PT)⁻0.1(PS) solid solution have been obtained using the conventional ceramic route. X-ray diffraction (XRD), energy dispersive spectrometry (EDS), and microstructure measurements were performed, as well as tests regarding the dielectric, ferroelectric, piezoelectric properties and electric conductivity of the PMN⁻PT⁻PS ceramic samples versus temperature. Results of the measurements show that the obtained PMN⁻PT⁻PS materials have good electrophysical properties and are well suited for use in micromechatronic and microelectronic applications.

Late-onset pericardial tamponade, bilateral pleural effusions and recurrent immune monoarthritis induced by ipilimumab use for metastatic melanoma.

While an important agent in the contemporary anti-melanoma armamentarium, ipilimumab is associated with serious immune reactions including late immune-mediated side effects. Recently, a case of late-onset acute pericarditis with tamponade was reported at 12 weeks after the last dose of ipilimumab. While polyarthralgia rheumatica has been previously documented with ipilimumab, we were not able to find any reports of recurrent monoarthritis with the use of this agent. Therefore, we present herein a unique case featuring a patient with late-onset autoimmune pleuropericarditis leading to cardiac tamponade at 24 weeks post-ipilimumab and recurrent late immune knee arthritis at 8 and 32 weeks, respectively. Furthermore, this late-onset toxicity seen with ipilimumab might also be expected with the PD1 inhibitors currently in clinical use. Timely diagnosis and prompt steroid use are crucial to ensure favorable clinical outcomes in these patients.