**What is neural code?**

A Morse code of elecrtic impulses on nerves, on cell membranes of neurons etc.

For instance electricity on for 1ms, electricity off for 2ms, electricity on for 1ms.

**What generates electricity in a cell?**

Opening of ion channels which allows movement of charges.

**Can you influence externally this?**

Yes, by applying an electromagnetic field (EMF), by providing electromagnetic energy of a specific frequency.

**Which frequencies are expected to have a biological effect?**

Those that can resonate with the ions implicated in biological activity, and in particular with the activity of neural cells; but also with our particles in general, e.g. the electron and the
proton.

**What does resonance of an ion mean?**

It means that the ion can take up the energy provided to it, flip its spin and acquire a higher energetic state.

**What happens if resonance is induced on ions e.g. calcium ions in proximity with ion channels? **

By aquiring a high energetic state, it will be like forcing their way towards the channel. They will be catapulted and the resulting flow of charges will change the voltage of the cell, the potential
of the cell membrane. An action potential will be generated and propagated, and an electrical message which will represent neural code will be created.

Please also refer to this page:

http://www2.information-book.com/biology-medicine/electromagnetic-signaling-magnetic-resonance/

Bothwell JH, Griffin JL.

https://www.ncbi.nlm.nih.gov/pubmed/20969720

Compasses can be made with a little effort "to point in another direction, but are in their most stable states when aligned with the Earth’s magnetic field and will relax back to pointing north as soon as they are released."

"A number of common biological elements have nuclei which behave much like these compasses; they will align themselves in a magnetic field, may be forced to point in another direction, and will relax back to point ‘north’ once released, usually within a few hundred milliseconds."

"The second point which we need to add to our compass analogy is that individual magnetic nuclei may be moved, or ‘flipped’, from one spin state to another by radiofrequency (RF) waves whose exact frequencies are diagnostic for the chemical element involved. This RF-wave induced flipping of magnetic nuclei was first observed over 70 years ago by Isidor Rabi’s group at Columbia University (Rabi, 1937; Rabi et al., 1938) and named nuclear induction. However, because some of the early theories to describe this nuclear flipping employed the idea of nuclei resonating at the frequencies at which they absorbed RF waves, Rabi’s ‘nuclear induction’ quickly became known as nuclear magnetic resonance, or NMR (Gorter & Broer, 1942)".

Indicative reference: Halliday, D., R.Resnick, J. Walker. Principles of Physics, Wiley,

Chapter 28 Magnetic Fields – (28-4) A circulating charged particle (page 730)

HyperPhysics: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/maspec.html#c2

A charge that moves in a magnetic field with velocity v perpendicular to the magnetic field lines will experience a magnetic force whose magnitude is F=qvB and whose
direction is given by the right hand rule.

The magnetic force will act a centripetal force F=mv^2 /R and the charge will do a circular motion:

F=Fc <=> qvB=m^2/R <=> R=mv/qB

As mentioned in https://en.wikipedia.org/wiki/Gyroradius:

The radius of the circular motion, termed gyroradius, Larmor radius, or cyclotron radius is given by the above equation.

The angular frequency of this circular motion is known as the gyrofrequency, or cyclotron frequency, and can be expressed as

ω=v/R=qB/m

in units of radians/second

It can also be expressed in Hertz:

f =qB/2πm

By tuning a suitable oscillating electric field to this frequency we can add add kinetic energy to the particles. This is the application of the cyclotron, a
particle accelerator from which we derive the name “cyclotron resonance”.

Reference: https://en.wikipedia.org/wiki/Cyclotron_resonance

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(From same book) Chapter 26 Electric Fields – Section 22-6 A point charge in an electric field (page 573)

Electric charge moving in an electric (electrostatic) field receives a force:

F=qE

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The combined electromagnetic force is termed Lorentz force:

F=qE+qvB

http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfor.html#c2

How does a compass work? It aligns itself with the magnetic field of the Earth, and this occurs because a torque is exerted on the compass needle by the Earth.

What is moment in physics?

“In physics, a moment is a turning effect of a force. It is an expression involving the product of a distance and a physical quantity (…). For example, the moment of
force acting on an object, often called torque, is the product of the force and the distance from a reference point.”

It causes rotation of the object.

What is magnetic moment? What is the magnetic moment of a magnet?

“The magnetic moment of a magnet is a quantity that determines the torque it will experience in an external magnetic field. A loop of electric current, a bar magnet,
an electron, a molecule, and a planet all have magnetic moments.”

Consider a short bar magnet and a long one. If it is a short one, then one pole cancels out the other. The magnetic force that a bar magnet produces depends on the
strength of its poles and the distance separating them. Consider those two magnets on a rotating axis and a magnetic field being brought into proximity (e.g. a third strong magnet). The torque that
will be induced depends on their strength as well as their length.

Interesting link: http://www.usneodymiummagnets.com/magnetic-moment.html

Indicative magnetic fields B

Earth: 50μT

Typical refrigerator magnet: 5 mT

Neodymium magnet: 1.25T (A coin-sized neodymium magnet can lift more than 9 kg and can erase credit cards).

“All objects have mass; so if an object is moving, then it has momentum - it has its mass in motion. The amount of momentum that an object has is dependent upon two
variables: how much stuff is moving and how fast the stuff is moving. Momentum depends upon the variables mass and velocity.”

Compare a small bicycle going slow and a car going fast.

In the above case we talk about linear momentum, where the vehicles run km (or miles) per hour. Linear velocity and mass make up linear momentum.

What about a revolving door or an ice skater who rotates around his axis? We could maybe say that they run angles or degrees in the unit of time. We have angular
velocity (rotational speed).

What happens if an ice skater brings his arms closer to the vertical axis of rotation? That actually means that he brings part of her mass closer to that axis. His
angular velocity will increase. In this case we do not use mass but we use inertia and specifically the moment of inertia. The latter and angular velocity make up angular momentum.

“The conservation of angular momentum explains the angular acceleration of an ice skater as she brings her arms and legs close to the vertical axis of rotation. By
bringing part of the mass of her body closer to the axis she decreases her body's moment of inertia. Because angular momentum is the product of moment of inertia and angular velocity, if the angular
momentum remains constant (is conserved), then the angular velocity (rotational speed) of the skater must increase.”

How does the magnetic component of electromagnetic fields/radiation, Earth magnetic field, an MRI chamber affect particles?

Consider an ice skater with magnets embedded on his suit doing a rotation around his axis.

The effect of the mentioned external field will depend first on his "magnetic presence", and in particular on the strength of his magnetism (his suit) and how it is distributed (for instance do
different parts cancel out etc.) These notions represent the magnetic momentum.

It also depends on the magnitude of him motion, on his momentum.

For linear momentum, e.g. a bicycle moving and a car moving (e.g. they run km or miles per hour) or an apple and a feather falling, we say that this is dependent on mass and velocity. If the
subject does a rotation, it runs "degrees" or "angles" per hour (in the unit of time). So for rotations we use the notion of angular

momentum. Angular momentum however does not use mass but an opposite notion, that of inertia (not willing to move!). When an ice skater brings his arms closer to the body, we observe that he is
rotating extremely fast around himself! By bringing mass closer to the axis he reduces his inertia. So different ice skaters can have different rotational velocities or angular velocities and
different inertias. These notions represent angular momentum.

How can you tell if an external magnetic field will affect the ice skater? Let us try to create a logic condition: one could say that you need to provide a sort of percentage, a ratio for the
above two factors combined. So to determine the outcome, you put the two influences in a ratio and create a mathematical expression. The new component you generate has been called gyromagnetic
ratio.

The gyromagnetic ratio for charged particles will be addressed below.

Excerpts from Lecture Notes by Assaf Tal:

"Induced Moments: Basic electromagnetism tells us that a current flowing in a closed loop will give off a magnetic field. The loop can be macroscopic, like a wire,
or microscopic, like an electron orbiting the nucleus. Far away from the current loop the field will look as if it were being generated by a magnetic dipole. If the magnetic loop is assumed to be
planar, the magnetic dipole will be perpendicular to the loop, and have a magnitude given by m=IA where I is the current in the loop and A is the area enclosed by the loop (cf. figure)."

"Intrinsic Moments: It also appears that the fundamental particles - the proton, neutron and electron – carry intrinsic magnetic moments. That is, they “give off” a
magnetic field as if a magnetic dipole were fixed to them, without having any current associated with them."

"The phenomenon of intrinsic magnetic moments is directly related to another fundamental property of these particles called spin, and one speaks of a "nuclear spin"
or an "electron spin". This is intrinsic angular momentum possessed by all electrons, protons and neutrons. Semi-classically, we can think of the proton or electron as a rotating ball of charge. The
rotating charge can be thought of as loops of current, which give off a magnetic moment. In reality this picture is wrong, and you should always keep in mind spin is an intrinsic, somewhat weird
quantum mechanical property; for example, the neutron has no charge and yet has a spin magnetic moment. The semi-classical picture gets one thing right: the angular momentum and magnetic moment of
the spinning sphere are parallel: m = γ S

The constant of proportionality is known as the gyromagnetic ratio, and is given in units of γ = Coulomb * Hz = kg * Tesla."

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'Magnetic Fields Cause Magnetic Moments To Precess: The Bloch Equations'

'How do magnetic fields affect magnetic moments? This is a question in basic electromagnetism, from which we will merely borrow the answer: as long as the
wavelengths involved are long enough, which is the case for MRI, then:

1. m feels a force given by F=(m * ) * B

2. m feels a torque given by τ= m * B

The force F turns out to be completely negligible in-vivo.

As for the torque, (...)

This equation is known as the Bloch Equation (BE). It is actually three separate equations:

(...)

These are three coupled first order linear differential equations. As far as differential equations (...). However, if the magnetic field is constant, their solution
is quite straightforward, and I will quote here without proof.

"A spin m in a time-constant magnetic field B will precess around the field B at an angular velocity ω=γ|B| according to the left hand rule."

Let’s break this down slowly. First, a precession is a motion by which m traces out a cone around B, while keeping their angle θ fixed:

(...)

The sense of the rotation is determined using the left hand rule: take your left hand and curl it with the thumb pointing along the field B. The way your fingers
curl will tell you in which sense the magnetization is executing its precession. Finally, the angular velocity of the precession is fixed and given by ω=γ|B| (a negative γ will reverse the sense of
the rotation).

Since precession is really just a rotation of m about B, we can describe it mathematically using rotations. (...)"

Nuclear Magnetic Resonance

http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/nmr.html#c1

Link previously shared in a post by Dr. Robert Duncan (including an example of calculation for the resonance frequency of the electron at the magnetic field of the Earth).

Note: The gyromagnetic ratio is multiplied by the magnetic field of the Earth which is ~50μΤ (0.5 Gauss).

Electron resonance frequency:

28.025 GHz/T * 0.00005T= 1.40125 MHz

Similarly the proton resonance frequency is:

42.5781 MHz/T * 0.00005T= 2.129 KHz

There is evidence that there is influence of biological activity due to the above proton spin resonance in this study https://goo.gl/1D7DmN where yeast cells formed "pearl chains".

In the same way we can calculate the resonance frequencies for the nuclei that are implicated in biological activity.

Most important ones: Ca, K, Na, Mg, Cl, P

As mentioned at the above link, "an extensive list including the magnetic moments and Larmor frequencies of most elements can be found in Appendix A of Becker."

(Becker & Edwin 1969 p.381 - Note that the magnetic field is 2.35T)

Other useful links:

Interactive frequency map citing IUPAC below

http://www.nyu.edu/cgi-bin/cgiwrap/aj39/NMRmap.cgi

IUPAC: https://www.iupac.org/publications/pac/2001/pdf/7311x1795.pdf

Bruker: http://kodu.ut.ee/~laurit/AK2/NMR_tables_Bruker2012.pdf

NMR graphic table: http://www-usr.rider.edu/~grushow/nmr/NMR_tutor/periodic_table/nmr_pt_frameset.html

https://youtu.be/1-NA86aAMvY

A video previously shared by Leo Alexander Ängeslevä

https://en.wikipedia.org/

"The sensitivity of NMR signal detection depends on the gyromagnetic ratio (γ) of the nucleus. In general, the signal intensity produced from a nucleus with a gyromagnetic ratio of γ is proportional
to γ^3 because the magnetic moment, the Boltzmann populations, and the nuclear precession all increase in proportion to the gyromagnetic ratio γ. For example, the gyromagnetic ratio of (13)Carbon is
4 times lower than the proton, so the signal intensity it produced will be 64 times lower than that of a proton. However, noise also increases as the square root of the frequency, the sensitivity
therefore becomes roughly proportional to γ^(5/2). A (13)Carbon nucleus would be 32 times less sensitive than a proton, and (15)Nitrogen around 300 times less sensitive. Sensitivity enhancement
techniques are therefore desirable when recording an NMR signal from an insensitive nucleus."

A specific pulse sequence which mediates transfer of polarization from the sensitive nucleus to the insensitive one (selective population inversion) is described at section "Pulse sequence"https://en.wikipedia.org/

An example of such a pulse sequence is found at this article

http://www.cmrr.umn.edu/

Figure 3. Seven CHESS water suppression scheme (VAPOR) with optimized flip angles and timing. Calculated time dependence of the water Mz magnetization for three different values of nominal flip angle
(different B1 of the RF coil). Optimized time delays t1=5 150=ms, t2 5 80 ms, t3 =160 ms, t4 = 80 ms, t5 = 100 ms, t6 = 30

ms, t7 = 26 ms.