Methodology help needed - how to measure nail light absorbance

[wolass]

Hey guys

I would like to measure what wavelengths are absorbed by the human nail plate.

My only idea so far is to take the nail clippings, dissolve them in KOH and than pour this liquid sample into a spetrophotometer.

Do you see other options? 

I will be grateful for your help 

(I'm a medical student with main field of interest in dermatology)  

[Simon Quellen Field]

Absorbance when dissolved will not be the same as when whole.

Why do you want to know the absorbency?

That will help us give you the method that will work the best for your project.

-----

Get a free science project every week! "http://scitoys.com/newsletter.html"

--
-- You received this message because you are subscribed to the Google Groups DIYbio group. To post to this group, send email to diy...@googlegroups.com. To unsubscribe from this group, send email to diybio+un...@googlegroups.com. For more options, visit this group at https://groups.google.com/d/forum/diybio?hl=en
Learn more at www.diybio.org
---
You received this message because you are subscribed to the Google Groups "DIYbio" group.
To post to this group, send email to diy...@googlegroups.com.
To unsubscribe from this group, send email to diybio+un...@googlegroups.com.
Visit this group at http://groups.google.com/group/diybio?hl=en.
To view this discussion on the web visit https://groups.google.com/d/msg/diybio/-/DOboLyjC6R8J.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

[Nathan McCorkle]

with a fiber-optic based spectrometer, you could just do backscatter sampling, where a single fiber has light coming out, hit's your sample, and what is reflected back enters the same fiber then splits off to the detector... you could be getting nailbed data that way though.

KOH might work to dissolve things, but it could also cause bands to shift or appear/disappear completely as you'd be denaturing some proteins (at least), you could also try meat tenderizer (or fresh pineapple juice or papaya seed extract) for the protease activity

here are some somewhat looking relevant papers

http://www.google.com/patents?hl=en&lr=&vid=USPAT6631199&id=pCoOAAAAEBAJ&oi=fnd&dq=backscatter+spectroscopy+fiber+nailbed+keratin&printsec=abstract#v=onepage&q&f=false

http://www.google.com/patents?hl=en&lr=&vid=USPAT8145286&id=tc4KAgAAEBAJ&oi=fnd&dq=backscatter+spectroscopy+fiber+nailbed+keratin&printsec=abstract#v=onepage&q&f=false

(ctrl-f nail here, there are some images at the end) http://spx.arizona.edu/Theses/Lovisa_Thesis.pdf

On Wed, Nov 21, 2012 at 7:52 AM, wolass <wol...@gmail.com> wrote:

--

-- You received this message because you are subscribed to the Google Groups DIYbio group. To post to this group, send email to diy...@googlegroups.com. To unsubscribe from this group, send email to diybio+un...@googlegroups.com. For more options, visit this group at https://groups.google.com/d/forum/diybio?hl=en
Learn more at www.diybio.org
---
You received this message because you are subscribed to the Google Groups "DIYbio" group.
To post to this group, send email to diy...@googlegroups.com.
To unsubscribe from this group, send email to diybio+un...@googlegroups.com.
Visit this group at http://groups.google.com/group/diybio?hl=en.
To view this discussion on the web visit https://groups.google.com/d/msg/diybio/-/DOboLyjC6R8J.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

--
-Nathan

[wolass]

I want to investigate wether there is a difference in wavelenghts absorbed by healthy nails and nais infected with pathogenic fungi.

I am also trying to figure out an artificial nail model to use in onychomycosis trials.

Nathan - nailbed is my main interest as this is where fungi grow. I havent thought of your method, but it is worth investigating. Thank You!!!

I will also have to look if there is any fiber based spectrometer lying around :)

Yes i do not want tissue denaturation - this is why i did't want the KOH method, as specific fungal strains may give different wavelength absobance.

[Nathan McCorkle]

Would trying to PCR then sequence fingernail clipping DNA work? You could design an assay using 28S rRNA or something like that to determine what species are present? I don't know if that's the kind of info you want.

Sequencing and Analysis of Fungal rRNA Operons for Development of Broad-Range Fungal PCR Assays

Prasanna D. Khot, Daisy L. Ko, and David N. Fredricks

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2655463/

To view this discussion on the web visit https://groups.google.com/d/msg/diybio/-/rBMb-8GWvk4J.

For more options, visit https://groups.google.com/groups/opt_out.

--
-Nathan

[wolass]

Well, I thought simply culture would be enough to determine the strain. PCR is rarely used in clinical practice in Poland, so every physician relies on mycological diagnosis.
Thanks for your help.

[Simon Quellen Field]

I would bet that a wideband photodetector surrounded by some different colored LEDs

(infrared, red, yellow, green, blue, violet, ultraviolet) and placed against the nail would

give you plenty of data to make the decision. Pot them in black silicone so the sensor

only sees the reflected and scattered light (not direct light from the LEDs), and then

switch each LED on for a tenth of a second while reading the sensor output. Now you have

seven channels of data, and you can calibrate it against known healthy and infected nails.

-----

Get a free science project every week! "http://scitoys.com/newsletter.html"

To view this discussion on the web visit https://groups.google.com/d/msg/diybio/-/Nbs6Tap0WVsJ.

[wolass]

Wow Simon, that is something new, what actually could be done with little money investment. I like the idea, although i'm not shure if it would be that accurate. I guess we have to build it and see.

W dniu czwartek, 22 listopada 2012 00:52:43 UTC+1 użytkownik Simon Field napisał:
> I would bet that a wideband photodetector surrounded by some different colored LEDs
> (infrared, red, yellow, green, blue, violet, ultraviolet) and placed against the nail would
>
>
> give you plenty of data to make the decision. Pot them in black silicone so the sensor
> only sees the reflected and scattered light (not direct light from the LEDs), and then
>
>
> switch each LED on for a tenth of a second while reading the sensor output. Now you have
> seven channels of data, and you can calibrate it against known healthy and infected nails.
>
>
>
>
>
>

> -----Get a free science project every week! "http://scitoys.com/newsletter.html"

[Xabier Vázquez Campos]

Well, theoretically could be possible since these fungi produce color alterations.

Don't know if dissolving in KOH would be the best option but maybe proteinase K, pretty common in any bio-related lab. It won't be a so aggressive digestion (except for all proteic stuff) and less prone to degrade other substances that can be present (thinking that they might be components affecting the absorbance).

Other idea could be look for degradation by products generated by the keratinolytic fungi, in case they produce something "special". Digestion of keratin itself will just give aminoacids.


Have you consider FTIR? It is quite analytic but if something that shouldn't be on the nail is present should be easy to see and some machines don't even need any sample preparation

[Josiah Zayner]

Realistically I think the biggest problem is not reading data using light from through or from a nail, they do this all the time with O2 sensors. The biggest problem is _how_ do you differentiate an infected nail from a non-infected one. Perhaps you say differences in absorbance, but every single nail will have differences in scatter/absorbance. It would be easy to detect serious infections but then again those can be seen by the eye. 

What specific properties of small quantities of fungus do you think will give it a distinct scatter/absorbance as say compared to dirt, bacteria, yeast or psoriasis? 

PCR is cheap easy and can detect fungus on a low level. So can just taking a swab and looking at it under a microscope or culturing the fungus. What makes an photometric detection method better? 

 

Fast and reliable PCR/sequencing/RFLP assay for identification of fungi in onychomycoses
http://jmm.sgmjournals.org/content/55/9/1211.full

[Simon Quellen Field]

The fungus is underneath the nail.

Taking a culture involves cutting through the nail to reach it.

Not something you want to do routinely.

I would expect a profile from seven or eight different wavelengths to be pretty good

at distinguishing fungus from bacteria and pure scattering (which would affect all wavelengths

to much the same degree, i.e. no absorbance).

If two of the wavelengths are in the infrared and one is in the ultraviolet, it is possible that

the detector would be more sensitive and reliable than the human eye. I have made chlorophyll

detectors that can tell real plants from fake, even when the human eye cannot. And they only used

four LED colors (one in the infrared).

Another benefit is that the UV LED could be used as a treatment, as well as a detector.

:-)

-----

Get a free science project every week! "http://scitoys.com/newsletter.html"

To view this discussion on the web visit https://groups.google.com/d/msg/diybio/-/a2PnDHyC3t8J.

[Josiah Zayner]

Simon, they routinely take nail scrapings. The PCR, microscope, culture methods are routine. A profile from 7 or 8 different wavelengths? How do you expect this to be "good"? Just because you assume it will be?

Again, what component of the fungus is going to give a strong enough reading above background/contaminated scatter? Bacteria, Yeast, normal nail damage, dried blood &c.

Telling a plastic plant from non plastic plant I hardly find a complex photometric accomplishment. I bet I could do it with a single LED at ~600-700nm. This is not a sound reason for why 7 or 8 LEDs would work. 

PCR can detect DNA from single cells. How many cells do you expect to need to use scatter? 

Using a microscope and/or PCR, types and strains of fungus and most things one would want to know can be discovered. There is idosyncratically no way to do this with light scatter.

[Jeswin]

On Thu, Nov 22, 2012 at 2:49 PM, Josiah Zayner <josiah...@gmail.com> wrote:
> one would want to know can be discovered. There is idosyncratically no way
> to do this with light scatter.
>

You know, if you tell any grad student, inventor, etc that his idea
won't work without letting them figure out if it will or not, no one
will advance science. Maybe it won't work. Maybe he will find a way to
make it work. Let him figure it out.

And I agree with his point. There are very few clinical PCR assays.

[Josiah Zayner]

I was not telling anyone that their idea wouldn't work. 

What I know is that doing experiments just "because" is not a good way to advance science that is not how science is advanced. Science is advanced by choosing a problem that needs answering and can be answered. I can try and detect the existence of God using LEDs because no one can tell me it won't work. Or I can think about what I am actually trying to do and come up with a reasonable hypothesis so I don't waste my time. 90% of good science is thinking and developing a good question and a good way to answer it.

I am a Ph.D. student and if I whenever I goto my boss with any idea he asks me two questions as every good scientist should:

How specifically do you plan on doing this?

Why do you plan on doing this?

If someone wants to build a spectrophotometric nail fungus detector to learn something, I am all about it. If one is trying to build a spectrophotometric nail fungus detector to help detect nail fungus when there are already plenty of good ways to do that already I am slightly skeptical of the scientific benefit, which is why I posed some questions. I never said it was not possible. I was just asking what specifically people planned on looking for. This is what any good scientist would ask. 

That's what granting agencies ask, that is what everyone asks. Sure perhaps someone could stumble across something innovative but that is not a scientists goal. That is gambling and if you are going to gamble why do it with something like DIYBio when you could do it with room temperature superconductors and perhaps change the world.

Very few clincal PCR assays? I think you meant very many. 

https://www.google.com/search?q=clinical+pcr+assays

It is used to isolate and detect basically every type of infection. Can be used for detecting cancers and genetic diseases. In fact new born babies are screened for at least 21 disorders by LAW in the US within 48 hours of birth. 

--
-- You received this message because you are subscribed to the Google Groups DIYbio group. To post to this group, send email to diy...@googlegroups.com. To unsubscribe from this group, send email to diybio+un...@googlegroups.com. For more options, visit this group at https://groups.google.com/d/forum/diybio?hl=en
Learn more at www.diybio.org
---
You received this message because you are subscribed to the Google Groups "DIYbio" group.
To post to this group, send email to diy...@googlegroups.com.
To unsubscribe from this group, send email to diybio+un...@googlegroups.com.
Visit this group at http://groups.google.com/group/diybio?hl=en.

[Cathal Garvey]

> Why do you plan on doing this?

> That's what granting agencies ask, that is what everyone asks.

These are the kinds of concerns that one has to consider when operating
in a grant-funded environment. For someone just doing it to satisfy
their curiosity, there should be no need to explain *why*, only *how*.

> What I know is that doing experiments just "because" is not a good way to
> advance science that is not how science is advanced. Science is
advanced by
> choosing a problem that needs answering and can be answered.

I disagree. There is plenty of precedent in groundbreaking science where
someone was just scratching an itch and discovered something amazing.
Leaving even that aside, most of the science that allows real
advancement isn't goal-oriented, it's just dedicated to uncovering more
knowledge. I know I've benefited immensely from many, many papers
published from unassuming labs studying niche-y stuff like the precise
workings of irrelevant protein X in obscure species Y.

Further, there may be existing, reliable methods to do what he's
thinking of doing better. That shouldn't preclude investigating a new
method of doing it; who knows? Perhaps he'll discover that he can
reliably and non-invasively identify infections by spectrographic data,
which could easily be packaged into a rapid field test for areas where
PCR etc. are inconvenient. How many genuses of nail-infective fungi are
there in common circulation? Do they differ in absorption enough to ID
them from one another, and from a healthy nail?

I think it's worth trying out any new idea, no matter how outlandish or
redundant. At the very least, it'll scratch the itch and let you move
onto another question. At best, it generates a new way of doing, or knowing.

--
www.indiebiotech.com
twitter.com/onetruecathal
joindiaspora.com/u/cathalgarvey
PGP Public Key: http://bit.ly/CathalGKey

[Josiah Zayner]

There is not plenty of precedent. I would say sure, 100 years ago there was precedent but not now. Sure, sometimes "brute force" methods are required because not enough is known but I don't know any professional scientist working today who does experiments just "because". Sure, people want to find answers to questions but why try and find the answer to a question through research when it can be found through a few hours of reading papers? I would understand if there was no papers on spectrometry of cells but spectrometry has been around sooo long a person should be able to find something. You have to know if it is feasible first or you have no idea what to look for. How do you know if your result is just not an artifact? I challenge you to find a Nobel prize in the past 30 years that was acquired out of serendipity and not a clear goal. 

How do I reprogram cells to become pluripotent? Well first I need to understand what makes cells pluripotent, Oct4, Sox2, Nanog,C-Myc, Klf4, Lin28. You think this question would have been discovered or won a Nobel prize if someone just decided to try and add stuff to cells to see if it worked? 

All science is goal oriented. Understanding the function of obscure protein X is goal oriented. There are in fact standard methods for this. The goal was to uncover some new knowledge about protein X. It is an expressed protein so it "must" have a function.

Just because the topic of the thread is spectrophotometry I will again use it as an example. I can try different configurations of LEDs and different data analysis techniques taking derivatives and trying value decomposition but in the end there are an infinite number of possible configuration and analysis methods. One would then also have to test the device on a huge population of nails to prove that it actually works. How correct would a device like this have to be to be usable? 90%? 50%? 

Let us be logical, being logical is the goal of any good Scientist or Vulcan. There is plenty of literature and data on the composition of fungal cells, what do they contain different than other cells if anything? Does this thing absorb? Saying, "I have no clue but I am going to try this anyway." is being ignorant. Research and understanding is what builds science, not ignorance.

[Simon Quellen Field]

Actually, what I was describing was engineering, not science.

Multispectral analysis is how satellites determine what crops are growing where, and where

droughts are occurring, where marijuana farms are, etc. Applying it to "crops" of fungi growing

under a fingernail is simply engineering.

The current technology for detecting nail fungus uses the human eyeball.

Unfortunately, this requires training, and has a false positive rate that means invasive further

testing is done, with the accompanying pain and expense.

A simple, cheap device that can detect certain fungi in seconds would be useful. Similar devices

are already in use to detect fungal growths on strawberries and blueberries in automated

processing plants. The technique is also used to monitor oxygen levels in the blood non-invasively.

There is no way you are going to take a sample from the fingernail, amplify it using PCR, and

then detect fungal genes in a couple seconds with a cheap handheld device. And it is unlikely that

one of us will build that device in our basement. But it is fairly easy to get the results using

multispectral analysis and a $1 microprocessor. Any technique that uses the human eye as the

detector is open to automation using multispectral analysis and machine vision.

Detecting genes in a sample requires knowing which genes to look for, and there are many

commensal fungi that share 99% of their genome with pathogenic fungi, so you would have to

be fairly selective. But the visual methods rule out the commensal varieties simply because

the pathogenic ones will be responsible for almost all of the signal.

As for "All science is goal oriented", I think that is nonsense. Darwin did not board the Beagle

with the goal of coming up with the idea of evolution by natural selection. There are any number

of similar exceptions, from the discovery of penicillin to the discovery of dark energy.

-----

Get a free science project every week! "http://scitoys.com/newsletter.html"

[Josiah Zayner]

They use infrared cameras to detect marijuana because it has a heat signature. Not likely useful for fungus on a human body.

And again, for the third or fourth time, they use PCR regularly to detect this type of stuff did anyone look at that paper I posted? PCR has been used to determine, highly specifically, species in every kingdom of life. This is not a question or a hypothesis this is actual fact. 

What are these similar devices for strawberries? I looked online but could find no information on it.

Of course it requires knowledge of the gene to look for but a common technique is to use degenerate primers for an obvious target (ribosomal subunit intron, &c.).

The only reason pulse oximetry works is because there is so much blood and hemoglobin! Billions of red blood cells and protein molecules. If one needs a finger width thick amount of fungus to detect it I don't see that as useful or reasonable.

Well first off Dark Energy is just an explanation but you are completely wrong about it happening serendipitously, read up on it and Einstein and the cosmological constant. 

I find it hard to relate science from the late 1800s and early 1900s to now. They didn't even know what DNA was. Nowadays you can't just look under a microscope at some soil and have some Earth shattering discovery. However, this is just my opinion. Maybe I am completely wrong and this happens all the time.

If one cannot answer the simple question of what molecule one suggests would cause the difference in scattering I don't see a point in doing the experiment. I mean what would the controls be? Would you test that every fungus and every bacteria are different? Some? 

Anybody can dick around and call it science but if you actually want people to gain something from your knowledge and experiments science needs to be done in a reasonable way so ones results aren't just random artifacts. 

[Nathan McCorkle]

I actually didn't say to use just PCR, I said PCR for the rRNA then sequence. I agree with Simon that currently and in the near future this isn't quick or cheap, but I don't see the OP saying they wanted a field instrument... they simply said they were a medical student interested in this stuff. There's a good chance we could just tell them to find a good on-campus spectrometer, UV/VIS IR etc...

On Thu, Nov 22, 2012 at 3:08 PM, Josiah Zayner <josiah...@gmail.com> wrote:

he simple question of what molecule one suggests would cause the difference in scattering I don't see a point in doing the experiment.

well you would be looking at trillions of molecules probably, but there is a chance of discoloration with the fungus vs host-only, especially if you can get some signal in the UV.

--
-Nathan

[wolass]

Ok guys, thanks for all the interest you have shown here.

I'm not quite happy where the discussion is going.
I have figured that some just can not hold their couriosity where it belongs :)

Ok here is why i need to be able to investigate infected nails absorbance: (Just remember to give me proper credit when you recieve your Nobel Prize for this)
For some time now laser devices are used to eradicate fungi from under the nail plate as a minimally invasive procedure.
I'm not quite sure if the wavelength of 1064 nm which is the most commonly used to achieve this - is a proper wavelength.

I have did my part of research and believe me there is no data on nail absorbance in this context.

If I would find differences in absorbance of specific fungal strains and healthy nail then this data would be useful in saying which wavelength is apropriate to hit just the fungus!

Ok - now there is no secrets

I have just one personal regard - Josiah I appreciate you are concerned that everyone does proper science - but here is the thing - there is no one recepie for science as this is the most abstract and innovative field of life !
So stop paternalising your peers!
You did not give any relavant information in this discussion apart from the fact that PCR is the most accurae in recognising fungal species.

This is not the problem I asked to give me some pointers on.

Maybe the new info will help you to figure some other ways to figure out how we can measure NAIL light band ABSORBANCE. I DO NOT CARE ABOUT THE FUNGUS SPECIES AT THIS MOMENT.

Also let's cut the talk on how to conduct science - as this does not get us anywhere.

[Jeswin]

On Fri, Nov 23, 2012 at 1:38 AM, wolass <wol...@gmail.com> wrote:

> Ok here is why i need to be able to investigate infected nails absorbance: (Just remember to give me proper credit when you recieve your Nobel Prize for this)
> For some time now laser devices are used to eradicate fungi from under the nail plate as a minimally invasive procedure.
> I'm not quite sure if the wavelength of 1064 nm which is the most commonly used to achieve this - is a proper wavelength.
>

I believe Nathan wrote about laser treatment for acne and fungus
treatment found on a laser hobby forum. Archived post found at :
https://groups.google.com/forum/?fromgroups=#!topic/diybio/ZQj0vgfu3KA

==========BEGIN_POST_405nm laser supposedly treating acne and nail
fungus=======================
two guys reporting positive results on pg 2 of this forum post
(linked)... one for acne, one for curing toe fungus
http://laserpointerforums.com/f38/using-405nm-laser-treat-acne-68626-2.html

"
I don't know about treating acne but I used my ~100mW 405 on a toenail
fungus infection on my left great toe with teriffic success. I had
read about how toxic some of the prescription treatments are so I
thought I'd try some very intense near UV light on the fungus. I
played the unfocused laser output on the infected area of the toenail
once a day for a week then I waited for the nail to grow out and
sunuvagun if the nail didn't grow out normally without the
discoloration and 'knobbyness' the fungus was causing. Ah, the
miracles of coherent light 8-)
"

here is the wikipedia section citing 405nm acne deactivation
http://en.wikipedia.org/wiki/Propionibacterium_acnes#Photosensitivity

==========END_POST_405nm laser supposedly treating acne and nail
fungus=========================

Not sure if it is relevant but maybe it will give you some more leads.

[wolass]

phillyj thank You, but this is not the topic. I am aware of all the research done on laser treatment for onychomycosis. 

Any thougths on how to measure nail light absorbance?

[Josiah Zayner]

Again, a thought on how to measure nail light absorbance is to find a wavelength or two that is particular to fungus.

You came here with a question I came back with a question and you were miffed because I didn't do the work for you.

Search online, it is not hard:

http://cdn.intechopen.com/pdfs/9095/InTech-Optical_spectroscopy_on_fungal_diagnosis.pdf

How is the fungal spectra different than bacteria or is it even?

Maybe not the same genus species but you get my drift. Search... It is fun to hypothesize but even more fun to have real data to back up your point and or conclusions. 

phillyj: Infrared light is used to treat fungus not UV as I suspect the DNA damage and oncogenic properties of UV light should cause it to be used sparingly.

--
-- You received this message because you are subscribed to the Google Groups DIYbio group. To post to this group, send email to diy...@googlegroups.com. To unsubscribe from this group, send email to diybio+un...@googlegroups.com. For more options, visit this group at https://groups.google.com/d/forum/diybio?hl=en
Learn more at www.diybio.org
---
You received this message because you are subscribed to the Google Groups "DIYbio" group.
To post to this group, send email to diy...@googlegroups.com.
To unsubscribe from this group, send email to diybio+un...@googlegroups.com.
Visit this group at http://groups.google.com/group/diybio?hl=en.

[Jeswin]

Ok lets start again.

On Wed, Nov 21, 2012 at 10:52 AM, wolass <wol...@gmail.com> wrote:
> Hey guys
>
> I would like to measure what wavelengths are absorbed by the human nail
> plate.
>

You want to find the absorbance of the nail as it is presented on the
finger. Otherwise you could just measure or find the absorbance of
keratin. I am not sure

> My only idea so far is to take the nail clippings, dissolve them in KOH and
> than pour this liquid sample into a spetrophotometer.
>

Most people have said this won't work since you're changing the
structure and affecting absorbance.

> Do you see other options?
>
> I will be grateful for your help

Here are some links for you and others on the list to help find a solution:

[1] AA composition of human nail as measured by gas-liquid
chromatography (It shows how they collected the sample, nothing else
is probably relevant for your work)
http://www.clinchem.org/content/22/10/1608.full.pdf

[2] A chapter about the set-up of the nail bed and its components, if
anyone is interested:
http://ir.inflibnet.ac.in:8080/bitstream/10603/2434/9/09_chapter%201.pdf

[3] Percutaneous absorption test – A case of effectiveness evaluation
of skin-whitening cosmetics (Measuring affects of skin whitening
products; maybe applicable to nails?)
http://altweb.jhsph.edu/wc6/paper407.pdf

[4] "The Nail Plate's Lack Of Absorptive Capability"
According to "Nails - Review of Structure, Function and Strategies to
Treat Disorders," published by Linda D. Rhein, Ph.D., the nail plate
has little absorptive capability because of its high disulfide bond
content and its relatively low lipid and lipid bi-layer content.
Disulfide bonds create a tight structure, which is almost impermeable
to topical therapeutic agents. Also, the disulfide bonds shield the
hydrogen bonds from chemicals like urea, included in some topical
treatments, which could disrupt H-bonding and make penetration easier.
The lack of lipid elements in the nail plate impedes the penetration
of lipid-based therapeutic agents.
http://www.viviforyou.com/vivinal/absorption.html

[5] The effect of nail polish on pulse oximetry. (not sure how useful for you)
http://www.anesthesia-analgesia.org/content/67/7/683.long

Regarding article [5], can you modify oximeters for your purposes?

Good luck

[Nathan McCorkle]

On Wed, Nov 21, 2012 at 10:41 AM, wolass <wol...@gmail.com> wrote:

I want to investigate wether there is a difference in wavelenghts absorbed by healthy nails and nais infected with pathogenic fungi.

With Simon's idea of a bunch of easy to get colors, or with a full UV/VIS or FTIR spectrometer, you still might not be able to discern a difference by eye or intuition. Maybe you will be able to, but I think you'll need to rely on some data processing.

I'm trying to help a friend build recognition software based on neural networks, similar to this recent medical tumor identification software:

http://www.themarysue.com/google-science-fair-winner/

(sorry I couldn't find the code or google.com results, if someone else could dig that up, it would be better)

[Nathan McCorkle]

ahh here it is 

https://sites.google.com/a/googlesciencefair.com/science-fair-2012-project-64a91af142a459cfb486ed5cb05f803b2eb41354-1333130785-87/home