Observations of ELF (extremely low frequency) signatures arising from space vehicle disturbances of the ionosphere

We report on observations of extremely low-frequency (ELF) signatures during exit or reentry of space vehicles through the ionosphere. The two modes regularly observed gave signals that peaked at 5.6 and 11.2 Hz. The evidence points to the lower ionosphere, i.e., the D- and E-layers, as the generator of these signals. The measurements were performed using ground-based multiturn coil sensors located in Reno and San Diego. The nature of these signals is unclear at present but it is surmised that we are detecting either the evanescent fields of hydromagnetic waves traveling in the ionosphere or the oscillating geomagnetic field associated with these hydromagnetic waves.

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

10.21203/rs.3.rs-528037/v1 ◽

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

Journal of The Royal Society Interface ◽

10.1098/rsif.2012.1046 ◽

2013 ◽

Vol 10 (81) ◽

pp. 20121046 ◽

Cited By ~ 14

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.

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