Background/Aims: Anemia, a common condition in the elderly, could result from impaired formation and/or from accelerated loss of circulating erythrocytes. The latter could result from premature suicidal erythrocyte death or eryptosis characterized by phosphatidylserine (PS) exposure at the erythrocyte surface. Triggers of eryptosis include increased cytosolic Ca²⁺-concentration ([Ca²⁺]_i), oxidative stress and ceramide. The present study explored whether eryptosis is altered in elderly individuals and, if so, to identify underlying mechanisms. Methods: Blood was drawn from healthy young (n=11, age 31.3±1.7 years) and elderly (n=16, age 88.6±0.9 years) individuals. PS exposure was estimated from annexin V-binding, cell volume from forward scatter, [Ca²⁺]_i from Fluo3-fluorescence, reactive oxygen species (ROS) from 2',7'dichlorodihydrofluorescein fluorescence, reduced glutathione (GSH) from mercury orange fluorescence and ceramide from FITC-conjugated antibody binding in flow cytometry. Measurements were made in erythrocytes from freshly drawn blood and in erythrocytes exposed in vitro for 24 h to plasma from young or elderly individuals. Results: Elderly individuals suffered from severe anemia (hemoglobin 10.5±0.3 g/100 ml) despite enhanced number of reticulocytes (2.3±0.2%). The percentage of PS-exposing erythrocytes was significantly higher in the elderly (2.5±0.2%) than in the young volunteers (1.3±0.1%). The increase in PS exposure was paralleled by significant increase of ROS and significantly decreased levels of reduced GSH. Erythrocyte [Ca²⁺]_i, and ceramide abundance tended to be higher in the elderly, differences, however, not reaching statistical significance. Conclusions: The anemia of elderly individuals is mainly if not exclusively due to enhanced eryptosis, resulting at least in part from GSH deficiency and increased oxidative stress.

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We present a simple, low-cost, and environmental-friendly method for the fabrication of hybrid magnetorheological composites (hMCs) based on cotton fibers soaked with a mixture of silicone oil (SO), carbonyl iron (CI) microparticles, and iron oxide microfibers (μF). The obtained hMCs, with various ratios (Φ) of SO and μF, are used as dielectric materials for manufacturing electrical devices. The equivalent electrical capacitance and resistance are investigated in the presence of an external magnetic field, with flux density B. Based on the recorded data, we obtain the variation of the relative dielectric constant (ϵr′), and electrical conductivity (σ), with Φ, and B. We show that, by increasing Φ, the distance between CI magnetic dipoles increases, and this leads to significant changes in the behaviour of ϵr′ and σ in a magnetic field. The results are explained by developing a theoretical model that is based on the dipolar approximation. They indicate that the obtained hMCs can be used in the fabrication of magneto-active fibers for fabrication of electric/magnetic field sensors and transducers.

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An efficient, low-cost and environmental-friendly method to fabricate magneto-active fabrics (MAFs) based on cotton fibers soaked with silicone oil and iron oxide microfibers (mFe) at mass fractions 2 wt.%, 4 wt.% and 8 wt.% is presented. It is shown that mFe induce good magnetic properties in MAFs, which are subsequently used as dielectric materials for capacitor fabrication. The electrical properties of MAFs are investigated in a static magnetic field with intensities of 0 kA/m, 160 kA/m and 320 kA/m, superimposed on a medium-frequency electric field. The influence of mFe on the electrical capacitance and dielectric loss tangent is determined, and it can be observed that the electrical conductivity, dielectric relaxation times and magnetodielectric effects are sensibly influenced by the applied magnetic and electric fields. The results indicate that the MAFs have electrical properties which could be useful for protection against electromagnetic pollution or for health monitoring.