- Home
- EMF - Electromagnetic Field research
- Feel the force
Feel the force
- By Nicola Jones
- Published 05/9/2008
- EMF - Electromagnetic Field research
- Unrated
Feel the force
06 April 2002
Nicola Jones
Magazine issue 2337
MAGNETIC fields have been fingered in the past as a possible trigger for cancer,
causing public scares about living under power lines or working near strong
magnets. But no one could figure out how they might cause health problems
because they don't have enough energy to break chemical bonds or heat molecules
up. Now chemists have a hint of a possible mechanism.
They found that proteins in membranes can act like magnets themselves, and that
steady external magnetic fields of fridge-magnet strength can force them to bend into
line. If the same happens in the membranes of living cells, magnetic fields could
have a host of knock-on effects such as slowing down ion transfer and disrupting cell
signalling.
Researchers already knew that some biological membranes can align themselves
with a magnetic field just like iron shavings near a magnet. To find out how, Ron
Naaman and his colleagues from the Weizmann Institute of Science in Israel studied
the effect of a magnet on a simpler version of a membrane—a sheet of closely
packed polypeptide molecules, which are shaped like long coils that can wind either
clockwise or anticlockwise. These sheets have a similar structure to the proteins
embedded in biological membranes.
The researchers left polypeptide sheets in an external magnetic field for a few hours,
and found that the molecules leaned over, just like biological membranes did.
Surprisingly, the direction of the lean depended on the wind of the coil. Naaman
thinks this happens because the membrane develops its own magnetism.
Polypeptide chains have a slight negative charge at one end and a positive charge at
the other. If they are forced to sit next to each other in a sheet, electrons flow along
the helix from the negatively charged end in an attempt to minimise the charge
difference. This acts just like a current running through a coil of wire, inducing a
permanent magnetic field within the peptides. Its direction depends on the wind of
the helix (see Diagram).
"That is a striking observation," says Jim Valles, a biologist from Brown University in
Rhode Island. But he's not convinced that Naaman's work proves the polypeptide
coils really did become magnetic, or that the same mechanism would work in living
cells. "I consider it highly speculative," he says. Thomas Tenforde, a biophysicist
from Pacific Northwest National Labs, adds that the effects might not be large
enough to have significant biological effects. But, he says, "if there are subtle effects
that we've missed, then it's important to find them".
Epidemiological studies on people exposed to magnetic fields have been
inconclusive. But studies with rats have occasionally revealed effects such as
boosted immunity and higher rates of miscarriages.
The fields Naaman used were between 0.09 and 0.45 tesla—about the strength of
the field just next to a strong fridge magnet, but 10,000 times stronger than the
Earth's magnetic field or those produced by a mobile phone. MRI scans, in contrast,
expose patients to fields of up to 3 teslas. If Naaman's model does apply to biological
systems, our bodies could be subtly affected by anything from doorbells to car
engines, he says. He now plans to collaborate with biologists to see whether
magnetic fields affect ion transport in membranes.
Naaman doesn't think his theory would apply to higher frequency electromagnetic
radiation—such as the kind that comes from mobile phones—because the direction
of the external field flips too rapidly. But, he adds, any step towards understanding
how magnetism might affect health would help researchers looking at these fields
too.
Britain's National Radiological Protection Board is to conduct a review of the health
effects of static magnetic fields sometime in the next 18 months, according to
Richard Doll of Oxford University. "I know of no health hazards. But they're being
used at progressively higher and higher strengths," he says. "We think it's important
to look at it now."
From issue 2337 of New Scientist magazine, 06 April 2002, page 8
Source
http://www.newscientist.com/article/mg17423370.500
06 April 2002
Nicola Jones
Magazine issue 2337
MAGNETIC fields have been fingered in the past as a possible trigger for cancer,
causing public scares about living under power lines or working near strong
magnets. But no one could figure out how they might cause health problems
because they don't have enough energy to break chemical bonds or heat molecules
up. Now chemists have a hint of a possible mechanism.
They found that proteins in membranes can act like magnets themselves, and that
steady external magnetic fields of fridge-magnet strength can force them to bend into
line. If the same happens in the membranes of living cells, magnetic fields could
have a host of knock-on effects such as slowing down ion transfer and disrupting cell
signalling.
Researchers already knew that some biological membranes can align themselves
with a magnetic field just like iron shavings near a magnet. To find out how, Ron
Naaman and his colleagues from the Weizmann Institute of Science in Israel studied
the effect of a magnet on a simpler version of a membrane—a sheet of closely
packed polypeptide molecules, which are shaped like long coils that can wind either
clockwise or anticlockwise. These sheets have a similar structure to the proteins
embedded in biological membranes.
The researchers left polypeptide sheets in an external magnetic field for a few hours,
and found that the molecules leaned over, just like biological membranes did.
Surprisingly, the direction of the lean depended on the wind of the coil. Naaman
thinks this happens because the membrane develops its own magnetism.
Polypeptide chains have a slight negative charge at one end and a positive charge at
the other. If they are forced to sit next to each other in a sheet, electrons flow along
the helix from the negatively charged end in an attempt to minimise the charge
difference. This acts just like a current running through a coil of wire, inducing a
permanent magnetic field within the peptides. Its direction depends on the wind of
the helix (see Diagram).
"That is a striking observation," says Jim Valles, a biologist from Brown University in
Rhode Island. But he's not convinced that Naaman's work proves the polypeptide
coils really did become magnetic, or that the same mechanism would work in living
cells. "I consider it highly speculative," he says. Thomas Tenforde, a biophysicist
from Pacific Northwest National Labs, adds that the effects might not be large
enough to have significant biological effects. But, he says, "if there are subtle effects
that we've missed, then it's important to find them".
Epidemiological studies on people exposed to magnetic fields have been
inconclusive. But studies with rats have occasionally revealed effects such as
boosted immunity and higher rates of miscarriages.
The fields Naaman used were between 0.09 and 0.45 tesla—about the strength of
the field just next to a strong fridge magnet, but 10,000 times stronger than the
Earth's magnetic field or those produced by a mobile phone. MRI scans, in contrast,
expose patients to fields of up to 3 teslas. If Naaman's model does apply to biological
systems, our bodies could be subtly affected by anything from doorbells to car
engines, he says. He now plans to collaborate with biologists to see whether
magnetic fields affect ion transport in membranes.
Naaman doesn't think his theory would apply to higher frequency electromagnetic
radiation—such as the kind that comes from mobile phones—because the direction
of the external field flips too rapidly. But, he adds, any step towards understanding
how magnetism might affect health would help researchers looking at these fields
too.
Britain's National Radiological Protection Board is to conduct a review of the health
effects of static magnetic fields sometime in the next 18 months, according to
Richard Doll of Oxford University. "I know of no health hazards. But they're being
used at progressively higher and higher strengths," he says. "We think it's important
to look at it now."
From issue 2337 of New Scientist magazine, 06 April 2002, page 8
Source
http://www.newscientist.com/article/mg17423370.500
