Radio waves -- Tissue Refractive Index

[roxyboy]

TL;DR Summary

refractive index;radio waves;radio velocity

The refractive index of tissue is approx. 1.4 for light, but with with lower frequencies the refractive index decreases. What is the tissue refractive index for radio waves 1 Hz - 1 MHz?

 

[jbriggs444]

TL;DR Summary: refractive index;radio waves;radio velocity

The refractive index of tissue is approx. 1.4 for light, but with with lower frequencies the refractive index decreases. What is the tissue refractive index for radio waves 1 Hz - 1 MHz?

See if this post is helpful.

Did you have an application in mind?

 

[Baluncore]

The refractive index of tissue is approx. 1.4 for light, but with lower frequencies the refractive index decreases.

I think you will find that the RI is higher at radio frequencies.

To compute the refractive index, RI, requires that you first estimate or measure the relative permittivity, Er, of the flesh in question.

At radio frequencies, the RI, is the reciprocal of the velocity factor;
vf = 1 / √Er;
RI = √Er;
Unfortunately, there is a wide variation in the Er of flesh.
The dielectric constant of water is about, Er = 80.
Living tissue is mostly water, but it is bound in a way that reduces the Er to nearer 25. Some tissue is closer to Er = 100, others are closer to Er = 10.
That puts the RI of flesh at about; RI = 5.
Expect a range of RI between 3 and 10.
Edited to fix RI = 1 / vf;

 

[roxyboy]

I think you will find that the RI is higher at radio frequencies.

To compute the refractive index, RI, requires that you first estimate or measure the relative permittivity, Er, of the flesh in question.

At radio frequencies, the RI, is the velocity factor;
vf = 1 / √Er;

Unfortunately, there is a wide variation in the Er of flesh.
The dielectric constant of water is about, Er = 80.
Living tissue is mostly water, but it is bound in a way that reduces the Er to nearer 25. Some tissue is closer to Er = 100, others are closer to Er = 10.
That puts the RI of flesh at about; RI = 5.
Expect a range of RI between 3 and 10.

Is this a reliable source of the relative permittivity? https://itis.swiss/virtual-population/tissue-properties/database/dielectric-properties/

 

[Baluncore]

Is this a reliable source of the relative permittivity?

It looks to be about right to me.
I would use it, but cross-check and verify the results.

 

[roxyboy]

It looks to be about right to me.
I would use it, but cross-check and verify the results.

I got the result RI=3,2, but I expected much lower value, something above 1.

 

[Baluncore]

I got the result RI=3,2, but I expected much lower value, something above 1.

Note that the RI is the reciprocal of the vf, because RI is the amount by which the propagation of EM radiation is slowed down, relative to a vacuum.

A vacuum, or air, would be about 1.00 ;
If you got; RI = 3.2, then Er = 10.25
What did you measure, or where did you get that RI value ?

 

[Vanadium 50]

I think you might want to take a step back - what are you trying to do? Radio waves are long, and tissue is small. If the frequency is too low, you won't "see" much effect. To even start to see people-sized objects, you need to be in the VHF or higher - below 150 MHz or so and your radio wavelength is bigger than people are.

 

[Baluncore]

Radio waves are long, and tissue is small. If the frequency is too low, you won't "see" much effect.

At VHF, a crowd is but a quarter-wave coating, on the surface of the Earth.

 

[roxyboy]

I think you might want to take a step back - what are you trying to do? Radio waves are long, and tissue is small. If the frequency is too low, you won't "see" much effect. To even start to see people-sized objects, you need to be in the VHF or higher - below 150 MHz or so and your radio wavelength is bigger than people are.

That´t a good point, I didn´t realize this. However, despite long radio waves I may see the effect of harmonic frequencies. My aim is to try to influence electro-sensitive macromolecules with EM waves. The resonant wavelengths of macromolecules are naturally very short, so I have to work with subharmonic frequencies. To be able to calculate the fundamental wavelength accurately, I need to know the velocity factor. In a medium with lower VF the wavelength is longer compared a medium with higher VF for the same frequency.

 

[Baluncore]

The resonant wavelengths of macromolecules are naturally very short, so I have to work with subharmonic frequencies.

Save energy, by just generating the frequency range required to excite the molecule. Do you know what those frequencies are?

 

[tech99]

That´t a good point, I didn´t realize this. However, despite long radio waves I may see the effect of harmonic frequencies. My aim is to try to influence electro-sensitive macromolecules with EM waves. The resonant wavelengths of macromolecules are naturally very short, so I have to work with subharmonic frequencies. To be able to calculate the fundamental wavelength accurately, I need to know the velocity factor. In a medium with lower VF the wavelength is longer compared a medium with higher VF for the same frequency.

I think you could place the tissue between the plates of a capacitor and apply an alternating voltage. You do not need to use waves for your experiment.

 

[Vanadium 50]

If people are willing to walk into that giant bug zapper of course.

 

[roxyboy]

Save energy, by just generating the frequency range required to excite the molecule. Do you know what those frequencies are?

Some of them are in MHz some even in THz range.

 

[nasu]

So, you actually know the resonant frequencies and not the "resonant wavelengths"? Do you have a reference for these values?

 

[berkeman]

However, despite long radio waves I may see the effect of harmonic frequencies.

No. If your signal generator and amplifier are generating any significant harmonics, they have a problem and should be serviced.

 

[Vanadium 50]

Some of them are in MHz some even in THz range.

And you want the same equipment to do both? Not so easy.

 

[Baluncore]

Some of them are in MHz some even in THz range.

I agree.
I used to think there was one centre frequency that would activate one organic reaction. But, no matter how I tried to identify the band or centre frequency, I could not find a way to economically identify the specific channel required, without disturbing or overheating the system.

I wanted to radiate soil with a device like a GPR, to trigger gorse or thistle seed in the soil to germinate, so it could be sprayed with a herbicide once, rather than every year, for the next hundred years.

It seems that one flash of daylight is sufficient to trigger weed seed to germinate, and that occurs when the soil is cultivated during the day. So cultivating a field at night will trigger less germination than cultivating during the day. Regional farming practices have evolved in ways that produce results. We corrupt those practices with new technologies, at our risk.
Should a plough or harrow, have bright work lights when used at night? What colour should those lights be?

Chickens roost at night, but scratch through the soil during the day, exposing small seed to sunlight, triggering germination, and eating some of the bigger seed. Chickens are a lower technology and can be farmed profitably. At this stage, birds are still more productive than GPR at night.

My aim is to try to influence electro-sensitive macromolecules with EM waves.

EM radiation of flesh is as likely to cause as much bad chemistry as good.
Most of the time it will just warm up the bulk, by dielectric heating.

@roxyboy
I challenge you to provide links to the frequencies you have identified, and identify the molecule or chemical process that those key frequencies trigger.

 

[roxyboy]

I agree.
I used to think there was one centre frequency that would activate one organic reaction. But, no matter how I tried to identify the band or centre frequency, I could not find a way to economically identify the specific channel required, without disturbing or overheating the system.

I wanted to radiate soil with a device like a GPR, to trigger gorse or thistle seed in the soil to germinate, so it could be sprayed with a herbicide once, rather than every year, for the next hundred years.

It seems that one flash of daylight is sufficient to trigger weed seed to germinate, and that occurs when the soil is cultivated during the day. So cultivating a field at night will trigger less germination than cultivating during the day. Regional farming practices have evolved in ways that produce results. We corrupt those practices with new technologies, at our risk.
Should a plough or harrow, have bright work lights when used at night? What colour should those lights be?

Chickens roost at night, but scratch through the soil during the day, exposing small seed to sunlight, triggering germination, and eating some of the bigger seed. Chickens are a lower technology and can be farmed profitably. At this stage, birds are still more productive than GPR at night.EM radiation of flesh is as likely to cause as much bad chemistry as good.
Most of the time it will just warm up the bulk, by dielectric heating.

@roxyboy
I challenge you to provide links to the frequencies you have identified, and identify the molecule or chemical process that those key frequencies trigger.

This is a very complex topic and there are many possible mechanisms of effect. For acoustic vibrations can play a significant role in epigenetics. Protein molecules cannot be disintegrated by EM waves, such as water molecule is not disintegrated by a microwave oven. The molecule can only be vibrated and thus stimulated. I read a study where they tried to influence TP53 (tumor protein) by frequencies which led to delayed development of the pathology. But this is not currenly my point of interest.

I´m focused on vibrational disintegration of bacteria and viruses in-vivo. The eukaryotic cell differs from the cell by the bacterial presence of internal membranes and a cytoskeleton, a kind of microscopic internal skeleton, which ensures the interconnection of cellular structures. Therefore, the application of oscillating EM field on electrosensitive parts of bacterial cells leads to its inactivation. And the resonant frequencies can be identified using math according to the shape or mass.

For example bacterial DNA molecule can be considered a nano-antenna. Its length can be calculated on the basis of the number of nucleotides (bases). From a physical point of view, genomes are miniature dipole antennas in the case of the DNA double helix and monopole antennas in the case of the single-stranded RNA molecule. In both cases, an antenna of a given length is able to absorb the maximum amount of electromagnetic radiation with a wavelength equal to approximately twice the length of the antenna - resonant wavelength.

 

[Baluncore]

For example bacterial DNA molecule can be considered a nano-antenna. Its length can be calculated on the basis of the number of nucleotides (bases).

DNA is twisted, folded and packed in a way that prevents the length of the molecule being relevant. It would be relevant if you could get a chromosome out of the nucleus, and to the point where it could be laid out, several centimetres long, on the bench.

 

[roxyboy]

DNA is twisted, folded and packed in a way that prevents the length of the molecule being relevant. It would be relevant if you could get a chromosome out of the nucleus, and to the point where it could be laid out, several centimetres long, on the bench.

The genome can be affected indirectly by influencing the spatial organization or the conformational state of the bacterial DNA chromosome through the cell membrane. It is known that cell membranes are receptors not only for chemical but also for electromagnetic signals. Electromagnetic waves interact with cell membranes, which act as signal amplifiers, which are then received by the DNA through junctions where the DNA touches the membrane. The target of the EM waves can therefore be proteins that participate in maintaining the structural and functional integrity of the DNA chromosome. The influence of the spatial organization of the chromosome through the processes of molecular interaction due to the influence of the EM wave and the associated changes in the secondary structure of DNA lead to the disruption of the processes of replication, repair, etc.

 

[Baluncore]

The genome can be affected indirectly by influencing the spatial organization or the conformational state of the bacterial DNA chromosome through the cell membrane.

The genome is the sum of all the genetic information in a cell. It is not a specific molecular target, it is a collective concept.

It is known that cell membranes are receptors not only for chemical but also for electromagnetic signals.

I would like some references to that RF reception. Bacteria have a more primitive cell wall chemistry than multicellular organisms. I believe you would do better targeting the construction of the cell wall, as is done by antibiotics, than trying to influence a circular macromolecule, in an unpredictable position, through a complex cell wall.

When it comes to viruses, the protein chemistry of the tough surface is keyed geometrically at the molecular level, to protect the virus and to attack its prey. It takes a phage to unlock the protein capsid of a virus. The probability that you will find such a magic EM key frequency, is highly unlikely. The dimensions of the protein chemistry are close to the wavelength of IR.
If there was an EM trapdoor, radio transmitters would trigger all sorts of unwanted organic reactions, which is simply not the case in reality.
The best you can expect of RF, is to deliver thermal energy into the vicinity of the cell, and hope to cook the chemistry, just enough to sterilise the cell, or trick it into waking up, to move on with the natural process.

Electromagnetic waves interact with cell membranes, which act as signal amplifiers, which are then received by the DNA through junctions where the DNA touches the membrane.

I cannot understand how, a cell membrane could act as an RF amplifier, nor how you could know the internal arrangement of the genetic material, to line up an RF spectrum, to both pass the wall, and have the required effect on the inside.
I would welcome any references to the contrary.
I believe that you are dreaming of a fantasy world.

 

[renormalize]

Your post offers a series of questionable statements. So let's break it down and just consider just the first one:

Electromagnetic waves interact with cell membranes, which act as signal amplifiers, which are then received by the DNA through junctions where the DNA touches the membrane.

Can you cite peer-reviewed literature that supports this claim, with quantitative data like the frequency and intensity of the radiation that induces the effect? In particular, what evidence is offered that differentiates this from the standard effect of tissue heating in an electric field oscillating at sufficient frequency?

 

[berkeman]

Thread closed temporarily for Moderation...

 

[berkeman]

Thread is reopened. @roxyboy -- you need to post links to mainstream scientific references for each of the claims you have been making. That is how PF works. Thank you.

 

[roxyboy]

https://t.ly/GrBSa
https://www.scirp.org/journal/paperinformation.aspx?paperid=123945

 

[renormalize]

https://t.ly/GrBSa
https://www.scirp.org/journal/paperinformation.aspx?paperid=123945

The references cited are wholley inadequate to support your claims.

The first citation is to "Resonance effect of microwaves on the genome conformational state of E. coli cells" (1992) by Belyaev et al., but this work is unreplicated 30 years later. Indeed, the 2021 Nature review paper 5G mobile networks and health—a state-of-the-science review of the research into low-level RF fields above 6 GHz
by Karapidis et al. categorizes this study with the notation "Quality: Inadequate dosimetry and temperature control" (pg. 589). Moreover, the Nature authors
make the following comment regarding the whole series of papers by Belyaev and various co-authors: "The studies on the DNA conformation state change relied heavily on the AVTD method that has only been used by the Balyaev[sic] group and has not been independently validated." (pg. 593).

Your second citation is to a 2023 paper appearing in Open Access Library Journal from Scientific Research Publishing, about which Wikipedia says: "Scientific Research Publishing (SCIRP) is a predatory academic publisher of open-access electronic journals, conference proceedings, and scientific anthologies that are considered to be of questionable quality." (https://en.wikipedia.org/wiki/Scientific_Research_Publishing) As such, the second paper is unsuitable for citation on Physics Forums.

 

[berkeman]

@roxyboy -- The clock is ticking...

 

[Vanadium 50]

Protein molecules cannot be disintegrated by EM waves

Sure they can. It's just a question of frequency.

So your plan is to cure disease by exposing the patient to just the right radio frequencies to disrupt bacterial and viral DNA and not the patient's? This sound hard.

 

[Baluncore]

So your plan is to cure disease by exposing the patient to just the right radio frequencies to disrupt bacterial and viral DNA and not the patient's? This sound hard.

It is hard. Like chemotherapy, or the original homeopathy, poison the patient, to the edge of death, then hope.

 

[Vanadium 50]

I think it's got to be even harder than that.

First, DNA curls. So any "magic frequency" changes cell-by-cell depending on exactly how it's curled. Putting that aside, bacterial DNA looks like human DNA: the chemistry is the same. Only the content is different. You can't attack an A group to T group: you need a frequency that attacks the whole thing coherently. Figuring that out will be Real Doggone Hard, and building a transmitter that precise will be Real Doggone Hard.

 

[Baluncore]

@roxyboy
Target the molecular chemistry of the transcription process. That is the only time you will see the internal sequence of the DNA or RNA going past during replication. You need gene scissors, not a microwave oven.

 

[berkeman]

Thread paused for a bit for Moderation...

 

[berkeman]

The references cited are wholley inadequate to support your claims.

Agreed.

@roxyboy -- this thread will remain closed. If you have a valid reference that you want to ask questions about, start a new thread and post links for the reference and ask *specific* questions about that reference. Please avoid making assertions at PF that are not backed up by the mainstream scientific literature.