Publikationen an der Fakultät für Informatik und Automatisierung

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Wells, James; Ortega, Daniel; Steinhoff, Uwe; Dutz, Silvio; Garaio, E.; Sandre, Olivier; Natividad, Eva; Cruz, M. M.; Brero, Francesca; Southern, Paul; Pankhurst, Quentin A.; Spassov, Simo; ;
Challenges and recommendations for magnetic hyperthermia characterization measurements. - In: International journal of hyperthermia : official journal of the STM, the ESHO and the ASHO.. - Abingdon : Taylor & Francis Group, ISSN 1464-5157, Bd. 38 (2021), 1, S. 447-460

Purpose The localized heating of magnetic nanoparticles (MNPs) via the application of time-varying magnetic fields - a process known as magnetic field hyperthermia (MFH) - can greatly enhance existing options for cancer treatment; but for broad clinical uptake its optimization, reproducibility and safety must be comprehensively proven. As part of this effort, the quantification of MNP heating - characterized by the specific loss power (SLP), measured in W/g, or by the intrinsic loss power (ILP), in Hm2/kg - is frequently reported. However, in SLP/ILP measurements to date, the apparatus, the analysis techniques and the field conditions used by different researchers have varied greatly, leading to questions as to the reproducibility of the measurements.Materials and Methods An interlaboratory study (across N = 21 European sites) of calorimetry measurements that constitutes a snapshot of the current state-of-the-art within the MFH community has been undertaken. Identical samples of two stable nanoparticle systems were distributed to all participating laboratories. Raw measurement data as well as the results of in-house analysis techniques were collected along with details of the measurement apparatus used. Raw measurement data was further reanalyzed by universal application of the corrected-slope method to examine relative influences of apparatus and results processing.Results The data show that although there is very good intralaboratory repeatability, the overall interlaboratory measurement accuracy is poor, with the consolidated ILP data having standard deviations on the mean of ca. ± 30% to ± 40%. There is a strong systematic component to the uncertainties, and a clear rank correlation between the measuring laboratory and the ILP. Both of these are indications of a current lack of normalization in this field. A number of possible sources of systematic uncertainties are identified, and means determined to alleviate or minimize them. However, no single dominant factor was identified, and significant work remains to ascertain and remove the remaining uncertainty sources.Conclusion We conclude that the study reveals a current lack of harmonization in MFH characterization of MNPs, and highlights the growing need for standardized, quantitative characterization techniques for this emerging medical technology.



https://doi.org/10.1080/02656736.2021.1892837
Schmidt, Helmut; Hahn, Gerald; Deco, Gustavo; Knösche, Thomas R.;
Ephaptic coupling in white matter fibre bundles modulates axonal transmission delays. - In: PLoS Computational Biology : a new community journal.. - San Francisco, Calif. : Public Library of Science, ISSN 1553-7358, Bd. 17 (2021), 2, S. 1-24

Axonal connections are widely regarded as faithful transmitters of neuronal signals with fixed delays. The reasoning behind this is that extracellular potentials caused by spikes travelling along axons are too small to have an effect on other axons. Here we devise a computational framework that allows us to study the effect of extracellular potentials generated by spike volleys in axonal fibre bundles on axonal transmission delays. We demonstrate that, although the extracellular potentials generated by single spikes are of the order of microvolts, the collective extracellular potential generated by spike volleys can reach several millivolts. As a consequence, the resulting depolarisation of the axonal membranes increases the velocity of spikes, and therefore reduces axonal delays between brain areas. Driving a neural mass model with such spike volleys, we further demonstrate that only ephaptic coupling can explain the reduction of stimulus latencies with increased stimulus intensities, as observed in many psychological experiments.



https://doi.org/10.1371/journal.pcbi.1007858
Dutz, Silvio; Zborowski, Maciej; Häfeli, Urs; Schütt, Wolfgang;
Preface to the Special Issue "Scientific and Clinical Applications of Magnetic Carriers". - In: Journal of magnetism and magnetic materials : MMM.. - Amsterdam : North-Holland Publ. Co., ISSN 0304-8853, Bd. 525 (2021), 167667

https://doi.org/10.1016/j.jmmm.2020.167667
Schramm, Stefan; Dietzel, Alexander; Blum, Maren-Christina; Link, Dietmar; Klee, Sascha;
Light-field imaging of the human optic nerve head at different wavelengths - a case study. - In: Acta ophthalmologica : the official journal of the Nordic Ophthalmological Societies.. - Oxford : Blackwell, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.

https://doi.org/10.1111/j.1755-3768.2020.0140
Schramm, Stefan; Solf, Benjamin; Klee, Sascha;
Scatter measurement in the human eye based on a Shack-Hartmann wavefront aberrometer with extended field of view. - In: Acta ophthalmologica : the official journal of the Nordic Ophthalmological Societies.. - Oxford : Blackwell, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.

https://doi.org/10.1111/j.1755-3768.2020.0141
Link, Dietmar; Klee, Sascha;
Fundus image quality assessment for an eye model with cataract using adapted illumination patterns. - In: Acta ophthalmologica : the official journal of the Nordic Ophthalmological Societies.. - Oxford : Blackwell, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.

https://doi.org/10.1111/j.1755-3768.2020.0150
Blum, Maren-Christina; Solf, Benjamin; Klee, Sascha;
Photopic negative response during and after ocular direct current stimulation. - In: Acta ophthalmologica : the official journal of the Nordic Ophthalmological Societies.. - Oxford : Blackwell, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.

https://doi.org/10.1111/j.1755-3768.2020.0152
Solf, Benjamin; Blum, Maren-Christina; Klee, Sascha;
The effect of the stimulus eccentricity on the main component of the steady-state visual evoked potential. - In: Acta ophthalmologica : the official journal of the Nordic Ophthalmological Societies.. - Oxford : Blackwell, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.

https://doi.org/10.1111/j.1755-3768.2020.0181
Solf, Benjamin; Blum, Maren-Christina; Klee, Sascha;
Offset characteristic of transient and steady-state flash visual evoked potentials. - In: Acta ophthalmologica : the official journal of the Nordic Ophthalmological Societies.. - Oxford : Blackwell, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.

https://doi.org/10.1111/j.1755-3768.2020.0183
Dietzel, Alexander; Schramm, Stefan; Link, Dietmar; Klee, Sascha;
Light-field imaging for glaucoma diagnosis - reproducibility on one patient. - In: Acta ophthalmologica : the official journal of the Nordic Ophthalmological Societies.. - Oxford : Blackwell, ISSN 1755-3768, Bd. 99 (2021), S265, insges. 1 S.

https://doi.org/10.1111/j.1755-3768.2020.0193