scholarly journals Magnetoreception in laboratory mice: sensitivity to extremely low-frequency fields exceeds 33 nT at 30 Hz

2013 ◽  
Vol 10 (81) ◽  
pp. 20121046 ◽  
Author(s):  
Frank S. Prato ◽  
Dawn Desjardins-Holmes ◽  
Lynn D. Keenliside ◽  
Janice M. DeMoor ◽  
John A. Robertson ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Low Frequency ◽  
Good Alternative ◽  
Static Field ◽  
Laboratory Mice ◽  
Extremely Low Frequency ◽  
Ambient Magnetic Field ◽  
Detection Mechanisms ◽  
Biological Endpoint

Magnetoreception in the animal kingdom has focused primarily on behavioural responses to the static geomagnetic field and the slow changes in its magnitude and direction as animals navigate/migrate. There has been relatively little attention given to the possibility that weak extremely low-frequency magnetic fields (wELFMF) may affect animal behaviour. Previously, we showed that changes in nociception under an ambient magnetic field-shielded environment may be a good alternative biological endpoint to orientation measurements for investigations into magnetoreception. Here we show that nociception in mice is altered by a 30 Hz field with a peak amplitude more than 1000 times weaker than the static component of the geomagnetic field. When mice are exposed to an ambient magnetic field-shielded environment 1 h a day for five consecutive days, a strong analgesic (i.e. antinociception) response is induced by day 5. Introduction of a static field with an average magnitude of 44 µT (spatial variability of ±3 µT) marginally affects this response, whereas introduction of a 30 Hz time-varying field as weak as 33 nT has a strong effect, reducing the analgesic effect by 60 per cent. Such sensitivity is surprisingly high. Any purported detection mechanisms being considered will need to explain effects at such wELFMF.

Extremely low frequency alternating magnetic field–triggered and MRI–traced drug delivery by optimized magnetic zeolitic imidazolate framework-90 nanoparticles

Nanoscale ◽  
2016 ◽  
Vol 8 (6) ◽  
pp. 3259-3263 ◽  
Author(s):  
Jie Fang ◽  
Yong Yang ◽  
Wen Xiao ◽  
Bingwen Zheng ◽  
Yun-Bo Lv ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Drug Release ◽  
Low Frequency ◽  
Alternating Magnetic Field ◽  
Zeolitic Imidazolate Framework ◽  
Extremely Low Frequency

An extremely low frequency alternating magnetic field of 20 Hz was proved to be able to remarkably accelerate the drug release from optimized ZIF-90 nanospheres with incorporated Fe3O4 nanoparticles acting as actuator.

scholarly journals Influence of high-latitude geomagnetic pulsations on recordings of broadband force-balanced seismic sensors

2012 ◽  
Vol 1 (2) ◽  
pp. 85-101 ◽  
Author(s):  
E. Kozlovskaya ◽  
A. Kozlovsky
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Geomagnetic Latitude ◽  
Low Frequency ◽  
Auroral Oval ◽  
Polar Regions ◽  
Geomagnetic Pulsations ◽  
Seismic Sensors ◽  
Magnetic Poles ◽  
Magnetic Disturbances

Abstract. Seismic broadband sensors with electromagnetic feedback are sensitive to variations of surrounding magnetic field, including variations of geomagnetic field. Usually, the influence of the geomagnetic field on recordings of such seismometers is ignored. It might be justified for seismic observations at middle and low latitudes. The problem is of high importance, however, for observations in Polar Regions (above 60° geomagnetic latitude), where magnitudes of natural magnetic disturbances may be two or even three orders larger. In our study we investigate the effect of ultra-low frequency (ULF) magnetic disturbances, known as geomagnetic pulsations, on the STS-2 seismic broadband sensors. The pulsations have their sources and, respectively, maximal amplitudes in the region of the auroral ovals, which surround the magnetic poles in both hemispheres at geomagnetic latitude (GMLAT) between 60° and 80°. To investigate sensitivity of the STS-2 seismometer to geomagnetic pulsations, we compared the recordings of permanent seismic stations in northern Finland to the data of the magnetometers of the IMAGE network located in the same area. Our results show that temporary variations of magnetic field with periods of 40–150 s corresponding to regular Pc4 and irregular Pi2 pulsations are seen very well in recordings of the STS-2 seismometers. Therefore, these pulsations may create a serious problem for interpretation of seismic observations in the vicinity of the auroral oval. Moreover, the shape of Pi2 magnetic disturbances and their periods resemble the waveforms of glacial seismic events reported originally by Ekström (2003). The problem may be treated, however, if combined analysis of recordings of co-located seismic and magnetic instruments is used.

Extremely low-frequency pulses of faint magnetic field, weaker than the geomagnetic field, induce mitophagy to rejuvenate mitochondria

2021 ◽  
Author(s):  
Takuro Toda ◽  
Mikako Ito ◽  
Jun-ichi Takeda ◽  
Alkio Masuda ◽  
Nobutaka Hattori ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Geomagnetic Field ◽  
Low Frequency ◽  
Mitochondrial Mass ◽  
Complex Ii ◽  
Extremely Low Frequency ◽  
Mitochondrial Homeostasis ◽  
Weak Magnetic Fields ◽  
Transport Chain ◽  
Chemical Inhibition

Abstract Humans are frequently exposed to time-varying and static weak magnetic fields (WMF). However, the effects of faint magnetic fields, weaker than the geomagnetic field, have not been reported. We found that extremely low-frequency (ELF)-WMF, comprised of serial pulses of 10 µT intensity at 1–8 Hz, which was three or more times weaker than the geomagnetic field, reduced mitochondrial mass to 70% and the mitochondrial electron transport chain (ETC) complex II activity to 88%. Chemical inhibition of electron flux through the mitochondrial ETC complex II nullified the effect of ELF-WMF. Suppression of ETC complex II subsequently induced mitophagy by translocating parkin and PINK1 to the mitochondria and by recruiting LC3-II. Thereafter, mitophagy induced PGC-1α-mediated mitochondrial biogenesis to rejuvenate mitochondria. The lack of PINK1 negated the effect of ELF-WMF. Thus, ELF-WMF may be applicable for the treatment of human diseases that exhibit compromised mitochondrial homeostasis, such as Parkinson’s disease.

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