In clinical and biomedical applications of magnetic nanoparticle heating, the importance of accurate and precise heating rate measurements cannot be understated. There is currently no standard equipment, methodology, or reference materials to inform and validate data obtained from such measurements. Theoretical modelling relies upon data from such measurements to guide improvements and to distinguish among competing models. Yet, measurement methods vary and are often conducted under conditions that violate the underlying thermodynamic principles upon which the measurement is founded.
Robert Ivkov, Frederik Soetaert et al independently ascertained regions of data that adhere to the thermodynamic criteria, and yet even within these regions significant variability of measurement is observed. Variations within a single measurement actually exceed the variance among replicate measurements. Such variation within the measurements can be attributed to complex magnetohydrodynamic responses of the magnetic fluid and to heat transfer within the sample. Distinguishing between these effects is not possible without additional orthogonal measurements.
Check out this careful and important work for the magnetic hyperthermia community here. It was just published in the journal "Scientific Reports".
The composition or stoichiometry of magnetite and maghemite mixtures or solid solutions is an important parameter in the physical and geological sciences, and materials science. It is also significant in biomedical science, where magnetic nanoparticles are used both in vitro and clinically, and where both ferrous and ferric iron ions are known to play active roles in the production of reactive oxygen species. However, the accurate determination of the composition/stoichiometry can be problematic, as it requires either well-crystallised samples suitable for x-ray diffraction studies, or it relies on destructive testing methods involving chemical dissolution that, depending on the nature of the sample, are often either unfeasible or inappropriate.
Quentin Pankhurst together with different other groups from Denmark and Spain recently published a thorough paper on the determination of magnetite/maghemite ratios in magnetic nanoparticles. They used Fe-57 Mössbauer spectroscopy and curve-fitted it and then extracted the so-called "centre of gravity" parameter, which is the area weighted mean isomer shift at room temperature.
The authors focused in their paper on the application of the method to materials for which the more conventional techniques are not easily applied—such as in nanoparticles or poorly crystallised particles. It is somewhat salutary to note that the Mössbauer method may find application even in more routine assays.
Check out the paper here.
The basic idea in 1997, when we started the first ferrofluid workshop in Bremen (at that time „Bremer Ferrofluidworkshop“) had been to coordinate the few groups working with ferrofluids in Germany a bit better and to induce a somewhat stronger interaction. The result of this activity had been the establishment of the first DFG priority program for this field of research – the SPP 1104. In addition a series of conferences has been established – now lasting for 20 years.
The 16th German Ferrofluid Workshop (only 16, not 20 since no workshops had been held in the years of the international ICMF conferences) stands therefore for a remarkable anniversary. 20 years with continuous development of the research field, with the establishment of a second DFG priority program and with permanently growing interest in the national research community are a clear indication that a sustainable structure has been developed.This anniversary will be celebrated this year in Dresden – where the workshop has never been held before. Therefore we invite you for the 16th German Ferrofluid Workshop from July 17 - 19, 2017 in Dresden. The usual details for the conference, the registration and all further details can be found on the website under www.magnetofluiddynamik.de/ffworkshop16th/.
Stefan Odenbach is looking forward to welcome you in Dresden mid of July!
ETH researchers are developing a new and highly effective way of fortifying iron into food and drinks. Protein nanofibrils are formed from native whey protein. The researchers combined these nanofibrils with iron nanoparticles which can be readily absorbed by the body. The iron-coated whey protein nanofibrils can be administered either in powder or liquid form, and the new compound can be easily added to different types of food without affecting their taste or smell or color. Around 1.2 billion people worldwide suffer from iron deficiency, with women worse affected than men. The ingredients are cheap and in plentiful supply. This iron food supplement would also be a good alternative for people living in poor countries who are more prone to iron deficiency than those living in western industrialized nations.
Magnetocaloric devices hold the potential to satisfy the rising demand for cooling in the future. One of the challenges remaining is to reduce the high ecological footprint of the permanent magnets driving the magnetic cooling cycle. Existing devices use neodymium-iron-boron (NdFeB)-type permanent magnets, which account for more than 50% of the ecological footprint of the appliance. To overcome this hurdle, TU Darmstadt and Urban Mining Company have built the first working magnetocaloric demonstrator that uses recycled NdFeB as a magnetic field source. Coupling this with the optimization of the magnets and their geometry, it is possible to further reduce the ecological footprint. Together, these two approaches help to position magnetic cooling as a realistic and sustainable cooling technology.
See more here at TU Darmstadt's website.
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