Magnetic oxygen-loaded nanodroplets (MOLNDs) are a promising class of nanomaterials dually sensitive to ultrasound and magnetic fields, which can be employed as nanovectors for drug delivery applications, particularly in the field of hypoxic tissue treatment. Previous investigations were primarily focused on the application of these hybrid systems for hyperthermia treatment, exploiting magnetic nanoparticles for heat generation and nanodroplets as carriers and ultrasound contrast agents for treatment progress monitoring. This work places its emphasis on the prospect of obtaining an oxygen delivery system that can be activated by both ultrasound and magnetic fields. To achieve this goal, Fe3O4 nanoparticles were employed to decorate and induce the magnetic vaporization of OLNDs, allowing oxygen release. We present an optimized method for preparing MOLNDs by decorating nanodroplets made of diverse fluorocarbon cores and polymeric coatings. Furthermore, we performed a series of characterizations for better understanding how magnetic decoration can influence the physicochemical properties of OLNDs. Our comprehensive analysis demonstrates the efficacy of magnetic stimulation in promoting oxygen release compared to conventional ultrasound-based methods. We emphasize the critical role of selecting the appropriate fluorocarbon core and polymeric coating to optimize the decoration process and enhance the oxygen release performance of MOLNDs.

The detection of magnetic nanoparticles in a liquid medium and the quantification of their concentration have the potential to improve the efficiency of several relevant applications in different fields, including medicine, environmental remediation, and mechanical engineering. To this end, sensors based on the magneto-impedance effect have attracted much attention due to their high sensitivity to the stray magnetic field generated by magnetic nanoparticles, their simple fabrication process, and their relatively low cost. To improve the sensitivity of these sensors, a multidisciplinary approach is required to study a wide range of soft magnetic materials as sensing elements and to customize the magnetic properties of nanoparticles. The combination of magneto-impedance sensors with ad hoc microfluidic systems favors the design of integrated portable devices with high specificity towards magnetic ferrofluids, allowing the use of very small sample volumes and making measurements faster and more reliable. In this work, a magneto-impedance sensor based on an amorphous Fe73.5Nb3Cu1Si13.5B9 wire as the sensing element is integrated into a customized millifluidic chip. The sensor detects the presence of magnetic nanoparticles in the ferrofluid and distinguishes the different stray fields generated by single-domain superparamagnetic iron oxide nanoparticles or magnetically blocked Co-ferrite nanoparticles.

Radical polymerization is widely employed for the preparation of advanced materials with controlled properties and responsiveness. Depending on the radical initiator, different stimuli can trigger the beginning of the reaction. This work presents an innovative approach that exploits the heat released by magnetic nanoparticles when they are excited by an alternating current (AC) magnetic field to induce radical polymerizations. In particular, the use of cobalt ferrite (CoFe2O4) nanoparticles is explored for the preparation of polyacrylamide hydrogels, chosen as a model material to demonstrate the strategy. Magnetic and mechanical characterizations reveal that the materials possess properties similar to those of samples prepared by classical thermal polymerization. Indeed, magnetic hyperthermia is a versatile tool for remote temperature control in a localized space that can have different applications. An example is represented by its use for a selective volume polymerization in a thermosensitive environment, overcoming classical problems of both bulk thermal polymerization (e.g., not applicable in delicate environments) and photopolymerization (e.g., poor light penetration). The obtained results pave the way also for production of non-magnetic materials, in which magnetic nanoparticles are first concentrated in a small solution volume (by a permanent magnet) and then exploited to activate the polymerization of the whole material (by an AC magnetic field).

Magnetic hyperthermia is an oncological therapy that exploits magnetic nanoparticles activated by radiofrequency magnetic fields to produce a controlled temperature increase in a diseased tissue. The specific loss power (SLP) of magnetic nanoparticles or the capability to release heat can be improved using surface treatments, which can reduce agglomeration effects, thus impacting on local magnetostatic interactions. In this work, Fe3O4 nanoparticles are synthesized via a coprecipitation reaction and fully characterized in terms of structural, morphological, dimensional, magnetic, and hyperthermia properties (under the Hergt- Dutz limit). Different types of surface coatings are tested, comparing their impact on the heating efficacy and colloidal stability, resulting that sodium citrate leads to a doubling of the SLP with a substantial improvement in dispersion and stability in solution over time; an SLP value of around 170 W/g is obtained in this case for a 100 kHz and 48 kA/m magnetic field.

• Development and validation of in silico models, as a tool to investigate adverse eddy current effects during magnetic hyperthermia tests on mice and rats and to define safe EM field exposure levels. • Weak eddy current effects observed in mice for a large range of AC magnetic field parameters: maximum temperature increase of 0.25 °C and 0.8 °C in proximity to Hergt-Dutz limit and 4 W/kg SAR threshold, respectively. • Important eddy current effects observed in rats: maximum temperature increase around 7 °C found at the Hergt-Dutz limit, for magnetic fields applied along the body longitudinal axis. • Stronger eddy current effects when the magnetic field is applied transversally: maximum temperature increase around 14 °C found in rats at the Hergt-Dutz limit. • Mitigation of eddy current heating with the introduction of water boluses and the use of applicators targeted to tumour region size and position in the body. Magnetic hyperthermia is an oncological therapy that employs magnetic nanoparticles activated by alternating current (AC) magnetic fields with frequencies between 50 kHz and 1 MHz, to release heat in a diseased tissue and produce a local temperature increase of about 5 °C. To assess the treatment efficacy, in vivo tests on murine models (mice and rats) are typically performed. However, these are often carried out without satisfying the biophysical constraints on the electromagnetic (EM) field exposure, with consequent generation of hot spots and undesirable heating of healthy tissues. Here, we investigate possible adverse eddy current effects, to estimate AC magnetic field parameters (frequency and amplitude) that can potentially guarantee safe animal tests of magnetic hyperthermia. The analysis is performed through in silico modelling by means of finite element simulation tools, specifically developed to study eddy current effects in computational animal models, during magnetic hyperthermia treatments. The numerical tools enable us to locally evaluate the specific absorption rate (SAR) and the produced temperature increase, under different field exposure conditions. The simulation outcomes demonstrate that in mice with weight lower than 30 g the thermal effects induced by AC magnetic fields are very weak, also when slightly overcoming the Hergt-Dutz limit, that is the product of the magnetic field amplitude and frequency should be lower than 5·10 9 A/(m·s). Conversely, we observe significant temperature increases in 500 g rats, amplified when the field is applied transversally to the body longitudinal axis. A strong mitigation of side-effects can be achieved by introducing water boluses or by applying focused fields. The developed physics-based modelling approach has proved to be a useful predictive tool for the optimization of preclinical tests of magnetic hyperthermia, allowing the identification of proper EM field conditions and the design of setups that guarantee safe levels of field exposure during animal treatments. In such contest, the obtained results can be considered as valid indicators to assess reference levels for animal testing of biomedical techniques that involve EM fields, like magnetic hyperthermia, thus complying with the Directive 2010/63/EU on the protection of animals used for scientific purposes.

The development and plasticity of axons and dendrites in mammalian neurons may depend on the presence and phosphorylation state of cytoskeletal proteins, including certain microtubule-associated proteins. One of these proteins, microtubule-associated protein 1B, is modified by different protein kinases, which give rise to two major types of phosphorylated isoforms. The distribution of these isoforms in cultured hippocampal neurons has been studied using antibodies to specific phosphorylation-sensitive epitopes. Mode I-phosphorylated MAP1B is largely restricted to developing axonal processes, particularly at their distal regions including their growth cones where no mode I-dephosphorylated MAP1B is present. Axonal maturation is accompanied by dephosphorylation of MAP1B at mode I sites. Thus, mode I-phosphorylated MAP1B may be a marker for axonal growth. In contrast, mode II-phosphorylated MAP1B is abundant in the axonal and somatodendritic compartments, and no increased dephosphorylation occurs during maturation. These results are compatible with a role for the mode I phosphorylation of M AP1B (which might be catalysed by proline-directed protein kinases) in supporting a rapid axonal-specific growth mechanism and a more general role for the mode II phosphorylation of MAP1B (which seems to be catalysed by casein kinase II) in controlling axonal and dendritic growth and remodeling.

In silico models can be useful tools to guide preclinical tests of magnetic hyperthermia, which employs Magnetic Nanoparticles (MNPs) excited by AC magnetic fields, as heat mediators for cancer cure. We virtually reproduce the heating process induced by magnetic hyperthermia in murine models, as a function of field applicator features, properties and size of target tissue, MNP dose and animal size.

The fracture toughness of low-alloy steels significantly depends upon the microstructure, i.e. upon metallographic constituents amounts and distribution and other parameters like carbides distribution, grain size, etc. Almost all the available studies and experimental data concern single constituent microstructures, whereas specific industrial applications use steels containing variable fractions of tempered martensite and bainite, as well as ferrite-pearlite, due to the production cycle and especially to the heat treatment used. In these cases it is particularly difficult to estimate the fracture toughness on the basis of the available experimental data; thus, it isn’t possible in practice to evaluate (and minimize) the crack propagation risk. Molds for plastic automotive components are a peculiar example, being produced from pre-hardened large blocks. The fracture toughness of the core mixed microstructures, that can occupy parts of the mold face, being sought, KIc tests have been performed as a function of the sample position in a 1.2738 steel block, and results interpreted at the light of fracture morphology and local microstructure.