Correction of Z-axis distortion- request for opinion

[Michal Gdula-2]

Dear Confocalists,

I need opinion of somebody experienced in correcting spherical aberrations to
asses my approach.
I am using Carl Zeiss LSM 510M microscope (with 63x apochromat objective,
NA=1.4) and I noticed significant stretching in Z-axis.
I found out from the literature that most probably it happens because of
refraction index mismatch between immersion oil (Zeiss Immersol 518F
ne=1.518) and mounting medium (Vectashield, Vector ne=1.457) or between
refraction index of the specimen (20um thin skin cryosection processed
according to FISH procedure). I have also discovered lately that we are
supplied with the cover slips no. 1 with the thickness 130-160 um, whereas
the optimal is 170um, however it is written in the Zeiss manual that immerse
oil objective should be not sensitive to the differences in cover slip thikness.
One of my aims is to measure  distances between FISH signals in 3D and I
have to be  as accurate as possible.
So far I  have done chromatic shift correction using measurements of
differences between centroids of 0.5 um Tetraspeck beads in different
channels.
I am planning to measure z-axis distortion scanning 4um TetraSpeck beads
and then calculate the differences between dimensions in the x,y and z-axis. I
will prepare 2 slides with beads on the microscope slide and the second with
the bead on the cover slip to check the difference of the aberration in
different depths. This data will serve me to correct z-coordinates of FISH
signals – I will calculate average ratio x-axis/z-axis and multiply the z-
coordinates.
I know that some scientists use some more sophisticated ways for correction
of z-axis distortion. I would be grateful for any opinions and remarks.

Best wishes,

Michal Gdula
Research PhD student
[hidden email]
Bradford University

[Mark Cannell]

Hi

Yes, using NA objectives with the wrong mounting medium leads to big
problems for quantification...
Why not use a glycerol objective? Zeiss now has a high NA (1.3 I think)
glycerol objective available. If you go tis route you will need to pay
attention to coverslip correction collar setting so adding a few
~0.5-1.0 um beads to your mountant might be useful for visual check on
spherical aberration correction.

Regards Mark Cannell





 think)Michal Gdula wrote:

> Dear Confocalists,
>
> I need opinion of somebody experienced in correcting spherical aberrations to
> asses my approach.
> I am using Carl Zeiss LSM 510M microscope (with 63x apochromat objective,
> NA=1.4) and I noticed significant stretching in Z-axis.
> I found out from the literature that most probably it happens because of
> refraction index mismatch between immersion oil (Zeiss Immersol 518F
> ne=1.518) and mounting medium (Vectashield, Vector ne=1.457) or between
> refraction index of the specimen (20um thin skin cryosection processed
> according to FISH procedure). I have also discovered lately that we are
> supplied with the cover slips no. 1 with the thickness 130-160 um, whereas
> the optimal is 170um, however it is written in the Zeiss manual that immerse
> oil objective should be not sensitive to the differences in cover slip thikness.
> One of my aims is to measure  distances between FISH signals in 3D and I
> have to be  as accurate as possible.
> So far I  have done chromatic shift correction using measurements of
> differences between centroids of 0.5 um Tetraspeck beads in different
> channels.
> I am planning to measure z-axis distortion scanning 4um TetraSpeck beads
> and then calculate the differences between dimensions in the x,y and z-axis. I
> will prepare 2 slides with beads on the microscope slide and the second with
> the bead on the cover slip to check the difference of the aberration in
> different depths. This data will serve me to correct z-coordinates of FISH
> signals – I will calculate average ratio x-axis/z-axis and multiply the z-
> coordinates.
> I know that some scientists use some more sophisticated ways for correction
> of z-axis distortion. I would be grateful for any opinions and remarks.
>
> Best wishes,
>
> Michal Gdula
> Research PhD student
> [hidden email]
> Bradford University
>  

[Jeremy Adler-2]

A minor note of caution about using 4um microspheres to measure Z axis
dimensions - the microspheres have a refractive index(1.473)which differs
from your medium.

Why not use the thickness of your section as a reference, over a few
sections it should average out to 20um. Begs the question as to how the
cryostat is calibrated.




Dr Jeremy Adler

F451a

Cell Biologi

Wenner-Gren Inst.

The Arhenius Lab

Stockholm University

S-106 91 Stockholm

Sweden

tel [phone]
-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On
Behalf Of Michal Gdula
Sent: den 3 april 2009 12:21
To: [hidden email]
Subject: Correction of Z-axis distortion- request for opinion

Dear Confocalists,

I need opinion of somebody experienced in correcting spherical aberrations
to
asses my approach.
I am using Carl Zeiss LSM 510M microscope (with 63x apochromat objective,
NA=1.4) and I noticed significant stretching in Z-axis.
I found out from the literature that most probably it happens because of
refraction index mismatch between immersion oil (Zeiss Immersol 518F
ne=1.518) and mounting medium (Vectashield, Vector ne=1.457) or between
refraction index of the specimen (20um thin skin cryosection processed
according to FISH procedure). I have also discovered lately that we are
supplied with the cover slips no. 1 with the thickness 130-160 um, whereas
the optimal is 170um, however it is written in the Zeiss manual that immerse

oil objective should be not sensitive to the differences in cover slip
thikness.
One of my aims is to measure  distances between FISH signals in 3D and I
have to be  as accurate as possible.
So far I  have done chromatic shift correction using measurements of
differences between centroids of 0.5 um Tetraspeck beads in different
channels.
I am planning to measure z-axis distortion scanning 4um TetraSpeck beads
and then calculate the differences between dimensions in the x,y and z-axis.
I
will prepare 2 slides with beads on the microscope slide and the second with

the bead on the cover slip to check the difference of the aberration in
different depths. This data will serve me to correct z-coordinates of FISH
signals - I will calculate average ratio x-axis/z-axis and multiply the z-
coordinates.
I know that some scientists use some more sophisticated ways for correction
of z-axis distortion. I would be grateful for any opinions and remarks.

Best wishes,

Michal Gdula
Research PhD student
[hidden email]
Bradford University

[Guy Cox]

Well, the stretching should be 1.518 / 1.457 if simple RI difference is the cause - ie about 4%.  If you are seeing more than that you'd better look elsewhere - maybe a dodgy Z drive?  I suppose changes in SA with depth would add to the discrepancy, but that depends a lot on how great a depth you are measuring through.  Also, though it's true oil and coverslip should have the same RI, oil changes with temperature whereas glass doesn't (much) so if you  can use #1.5 and still have enough working distance it might be better.  

                                       Guy

Optical Imaging Techniques in Cell Biology
by Guy Cox    CRC Press / Taylor & Francis
    http://www.guycox.com/optical.htm
______________________________________________
Associate Professor Guy Cox, MA, DPhil(Oxon)
Electron Microscope Unit, Madsen Building F09,
University of Sydney, NSW 2006
______________________________________________
Phone [phone]     Fax [phone]
Mobile [phone]
______________________________________________
     http://www.guycox.net
-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Michal Gdula
Sent: Friday, 3 April 2009 9:21 PM
To: [hidden email]
Subject: Correction of Z-axis distortion- request for opinion

Dear Confocalists,

I need opinion of somebody experienced in correcting spherical aberrations to asses my approach.
I am using Carl Zeiss LSM 510M microscope (with 63x apochromat objective,
NA=1.4) and I noticed significant stretching in Z-axis.
I found out from the literature that most probably it happens because of refraction index mismatch between immersion oil (Zeiss Immersol 518F
ne=1.518) and mounting medium (Vectashield, Vector ne=1.457) or between refraction index of the specimen (20um thin skin cryosection processed according to FISH procedure). I have also discovered lately that we are supplied with the cover slips no. 1 with the thickness 130-160 um, whereas the optimal is 170um, however it is written in the Zeiss manual that immerse oil objective should be not sensitive to the differences in cover slip thikness.
One of my aims is to measure  distances between FISH signals in 3D and I have to be  as accurate as possible.
So far I  have done chromatic shift correction using measurements of differences between centroids of 0.5 um Tetraspeck beads in different channels.
I am planning to measure z-axis distortion scanning 4um TetraSpeck beads and then calculate the differences between dimensions in the x,y and z-axis. I will prepare 2 slides with beads on the microscope slide and the second with the bead on the cover slip to check the difference of the aberration in different depths. This data will serve me to correct z-coordinates of FISH signals – I will calculate average ratio x-axis/z-axis and multiply the z- coordinates.
I know that some scientists use some more sophisticated ways for correction of z-axis distortion. I would be grateful for any opinions and remarks.

Best wishes,

Michal Gdula
Research PhD student
[hidden email]
Bradford University

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[Armstrong, Brian]

Michael, to be clear, your Z resolution will be approximately 3 times
worse than your X,Y. Therefore, your Z will appear stretched. To address
this you will need to perform deconvolution on your Z-Stacks. I would
not worry too much the about RI of your oil and glycerin based mountant,
as this is a very common procedure to use an oil imm objective on a
glycerin based mounted sample and a glycerin imm objective will run
around $10K US. I would however insist on a 1.5 coverslip that is 170um
because your lens is designed for the angle created by that thickness
and it is easy and cheap to use the right coverglass. After
deconvolution I would recommend you use image software designed for
accurate 3D visualization such as Imaris or Amira or Volocity.
Cheers,

Brian D Armstrong PhD
Light Microscopy Core Manager
Beckman Research Institute
City of Hope
Dept of Neuroscience
1450 E Duarte Rd
Duarte, CA 91010
626-256-4673 x62872
http://www.cityofhope.org/research/support/Light-Microscopy-Digital-Imag
ing/Pages/default.aspx

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]]
On Behalf Of Michal Gdula
Sent: Friday, April 03, 2009 4:21 AM
To: [hidden email]
Subject: Correction of Z-axis distortion- request for opinion

Dear Confocalists,

I need opinion of somebody experienced in correcting spherical
aberrations to
asses my approach.
I am using Carl Zeiss LSM 510M microscope (with 63x apochromat
objective,
NA=1.4) and I noticed significant stretching in Z-axis.
I found out from the literature that most probably it happens because of

refraction index mismatch between immersion oil (Zeiss Immersol 518F
ne=1.518) and mounting medium (Vectashield, Vector ne=1.457) or between
refraction index of the specimen (20um thin skin cryosection processed
according to FISH procedure). I have also discovered lately that we are
supplied with the cover slips no. 1 with the thickness 130-160 um,
whereas
the optimal is 170um, however it is written in the Zeiss manual that
immerse
oil objective should be not sensitive to the differences in cover slip
thikness.
One of my aims is to measure  distances between FISH signals in 3D and I

have to be  as accurate as possible.
So far I  have done chromatic shift correction using measurements of
differences between centroids of 0.5 um Tetraspeck beads in different
channels.
I am planning to measure z-axis distortion scanning 4um TetraSpeck beads

and then calculate the differences between dimensions in the x,y and
z-axis. I
will prepare 2 slides with beads on the microscope slide and the second
with
the bead on the cover slip to check the difference of the aberration in
different depths. This data will serve me to correct z-coordinates of
FISH
signals - I will calculate average ratio x-axis/z-axis and multiply the
z-
coordinates.
I know that some scientists use some more sophisticated ways for
correction
of z-axis distortion. I would be grateful for any opinions and remarks.

Best wishes,

Michal Gdula
Research PhD student
[hidden email]
Bradford University


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[Stanislav Vitha]

I would also consider switching to a mounting medium with correct refractive
index (=same RI as immersion oil)  2,2-thiodiethanol comes to mind.  See
Staudt, 2007.  A 500 ml bottle can be had for ~$30.

1. Staudt, T., M.C. Lang, R. Medda, J. Engelhardt, and S.W. Hell, 2,2'-
thiodiethanol: a new water soluble mounting medium for high resolution optical
microscopy. Microsc Res Tech, 2007. 70(1): p. 1-9.

Stan Vitha
Microscopy and Imaging Center
Texas A&M University
 
On Fri, 3 Apr 2009 09:30:20 -0700, Armstrong, Brian <[hidden email]>
wrote:

>Michael, to be clear, your Z resolution will be approximately 3 times
>worse than your X,Y. Therefore, your Z will appear stretched. To address
>this you will need to perform deconvolution on your Z-Stacks. I would
>not worry too much the about RI of your oil and glycerin based mountant,
>as this is a very common procedure to use an oil imm objective on a
>glycerin based mounted sample and a glycerin imm objective will run
>around $10K US. I would however insist on a 1.5 coverslip that is 170um
>because your lens is designed for the angle created by that thickness
>and it is easy and cheap to use the right coverglass. After
>deconvolution I would recommend you use image software designed for
>accurate 3D visualization such as Imaris or Amira or Volocity.
>Cheers,
>
>Brian D Armstrong PhD
>Light Microscopy Core Manager
>Beckman Research Institute
>City of Hope
>Dept of Neuroscience
>1450 E Duarte Rd
>Duarte, CA 91010
>626-256-4673 x62872
>http://www.cityofhope.org/research/support/Light-Microscopy-Digital-Imag
>ing/Pages/default.aspx
>
>-----Original Message-----
>From: Confocal Microscopy List

[mailto:[hidden email]]

>On Behalf Of Michal Gdula
>Sent: Friday, April 03, 2009 4:21 AM
>To: [hidden email]
>Subject: Correction of Z-axis distortion- request for opinion
>
>Dear Confocalists,
>
>I need opinion of somebody experienced in correcting spherical
>aberrations to
>asses my approach.
>I am using Carl Zeiss LSM 510M microscope (with 63x apochromat
>objective,
>NA=1.4) and I noticed significant stretching in Z-axis.
>I found out from the literature that most probably it happens because of
>
>refraction index mismatch between immersion oil (Zeiss Immersol 518F
>ne=1.518) and mounting medium (Vectashield, Vector ne=1.457) or between
>refraction index of the specimen (20um thin skin cryosection processed
>according to FISH procedure). I have also discovered lately that we are
>supplied with the cover slips no. 1 with the thickness 130-160 um,
>whereas
>the optimal is 170um, however it is written in the Zeiss manual that
>immerse
>oil objective should be not sensitive to the differences in cover slip
>thikness.
>One of my aims is to measure  distances between FISH signals in 3D and I
>
>have to be  as accurate as possible.
>So far I  have done chromatic shift correction using measurements of
>differences between centroids of 0.5 um Tetraspeck beads in different
>channels.
>I am planning to measure z-axis distortion scanning 4um TetraSpeck beads
>
>and then calculate the differences between dimensions in the x,y and
>z-axis. I
>will prepare 2 slides with beads on the microscope slide and the second
>with
>the bead on the cover slip to check the difference of the aberration in
>different depths. This data will serve me to correct z-coordinates of
>FISH
>signals - I will calculate average ratio x-axis/z-axis and multiply the
>z-
>coordinates.
>I know that some scientists use some more sophisticated ways for
>correction
>of z-axis distortion. I would be grateful for any opinions and remarks.
>
>Best wishes,
>
>Michal Gdula
>Research PhD student
>[hidden email]
>Bradford University
>
>
>---------------------------------------------------------------------
>
>SECURITY/CONFIDENTIALITY WARNING:  
>This message and any attachments are intended solely for the individual or

entity to which they are addressed. This communication may contain
information that is privileged, confidential, or exempt from disclosure under
applicable law (e.g., personal health information, research data, financial
information). Because this e-mail has been sent without encryption, individuals
other than the intended recipient may be able to view the information, forward
it to others or tamper with the information without the knowledge or consent
of the sender. If you are not the intended recipient, or the employee or
person responsible for delivering the message to the intended recipient, any
dissemination, distribution or copying of the communication is strictly
prohibited. If you received the communication in error, please notify the
sender immediately by replying to this message and deleting the message and
any accompanying files from your system. If, due to the security risks, you do
not wish to receive further communications via e-mail, please reply to this
message and inform the sender that you do not wish to receive further e-mail
from the sender.  
>---------------------------------------------------------------------

[Michal Gdula-2]

Thank you very much for your answer.
NA 1.3 is smaller than NA 1.4 what means for me lower resolution. So far I will
need to stay with my oil immersion objective but maybe we will need to
consider buying this objective in the future.

Greetings
Michal Gdula

[Michal Gdula-2]

Thank you for your response!

I am almost sure that our cryostate is not extremly precise, especially with
thicker cryosections. I can see this because I need to make from 90 up to 140
2d Scans to get whole cryosection (0.2 um of step between the optical
sections).
What should I expect after difference of Refractive index (RI) between
tetraspeck beads and a medium? I know the ideas behind  refraction, and
breaking of the light beam when light passes through substances with
different RI. But since I want to scan surface of the bead?
Notabene when I scan beads covered with oil (I prepared different slides
mounted with vectashield, oil and water) They appeared to be 1um smaller in
xy plane... Do you think that different RI can have anything in common with
this? Is it possible that they are soluble in oil? - some of them looked damaged

Kind regards,

Michal Gdula


Subject: Re: Correction of Z-axis distortion- request for opinion
From: Jeremy Adler <[hidden email]>
Reply-To: Confocal Microscopy List
<[hidden email]>
Date: Fri, 3 Apr 2009 16:08:25 +0200
Content-Type: text/plain

A minor note of caution about using 4um microspheres to measure Z axis
dimensions - the microspheres have a refractive index(1.473)which differs
from your medium.

Why not use the thickness of your section as a reference, over a few
sections it should average out to 20um. Begs the question as to how the
cryostat is calibrated.




Dr Jeremy Adler

F451a

Cell Biologi

Wenner-Gren Inst.

The Arhenius Lab

Stockholm University

S-106 91 Stockholm

Sweden

 

[Michal Gdula-2]

Thank you very much for your response!
I scanned slides with 4um beads and the stretching seems to be at least 20%
of the bead. It is hard to say precisely because of blurring.
I checked beads mounted with vectasshield, water and immersion oil. The
biggest extension was in the water, and there was almost no extension in oil
(the spheres looked almost round in xz and yz). I know that it is not anything
new, but I think that it confirms that refraction index is in huge part
responsible for this aberration if not alone.

Best regards,

Michal Gdula


Subject: Re: Correction of Z-axis distortion- request for opinion
From: Guy Cox <[hidden email]>
Reply-To: Confocal Microscopy List
<[hidden email]>
Date: Sat, 4 Apr 2009 03:10:11 +1100
Content-Type: text/plain

Well, the stretching should be 1.518 / 1.457 if simple RI difference is the
cause - ie about 4%.  If you are seeing more than that you'd better look
elsewhere - maybe a dodgy Z drive?  I suppose changes in SA with depth
would add to the discrepancy, but that depends a lot on how great a depth
you are measuring through.  Also, though it's true oil and coverslip should
have the same RI, oil changes with temperature whereas glass doesn't (much)
so if you  can use #1.5 and still have enough working distance it might be
better.  

                                       Guy

 

[Michal Gdula-2]

Thank you for your answer!

I am aware that people estimate resolution of confocal microscope to 200-
300nm in xy and 600-700nm in z-axis. I have lately measured 4um Tetraspeck
beads and they appeared to be more than 1um longer in z-axis when mounted
with Vectashield, even more streched with water, and less when mounted
with immersion oil, which would tell that it is not only about resolution.
As far as I understand stretching caused by lower resolution in z-axis and by
some other phenomena can be removed by deconvolution after measuring the
point spread function (PSF).
The points that are below resolution of the confocal microscope will have the
PSF-like appearence. I think that this may be the reason of stretching caused
by lower resolution, in this case we should expect stretching of particular
points 300-400 nm (300-400nm from the top and bottom part of z-ahis would
give 600-800nm extension). I have stretching of more than 500 um (more than
1um i diameter  of the spheres, which also would tell that there shoould be
some other factor besides resolution.
Do you think tha deconvolution is able to remove effects of spherical
abberration? Soonner or later I will deconvolute my scans, I bought beads so
far.
So as to software which one do you think is the best? My co-workers say that
Amira is not user friendly, but it gives good results for surface rendering. Do
you think that deconvolution with plugins of imagej or with freeware
Imagesurfer is not reliable?
I am relatively new to all this topics and I would be gratefull for any remarks.

Best wishes,

Michal Gdula

Subject: Re: Correction of Z-axis distortion- request for opinion
From: Armstrong, Brian
Reply-To: Confocal Microscopy List
<[hidden email]>
Date: Fri, 3 Apr 2009 09:30:20 -0700
Content-Type: text/plain

Michael, to be clear, your Z resolution will be approximately 3 times
worse than your X,Y. Therefore, your Z will appear stretched. To address
this you will need to perform deconvolution on your Z-Stacks. I would
not worry too much the about RI of your oil and glycerin based mountant,
as this is a very common procedure to use an oil imm objective on a
glycerin based mounted sample and a glycerin imm objective will run
around $10K US. I would however insist on a 1.5 coverslip that is 170um
because your lens is designed for the angle created by that thickness
and it is easy and cheap to use the right coverglass. After
deconvolution I would recommend you use image software designed for
accurate 3D visualization such as Imaris or Amira or Volocity.
Cheers,

Brian D Armstrong PhD
Light Microscopy Core Manager
Beckman Research Institute
City of Hope
Dept of Neuroscience
1450 E Duarte Rd
Duarte, CA 91010
626-256-4673 x62872
http://www.cityofhope.org/research/support/Light-Microscopy-Digital-Imag
ing/Pages/default.aspx

 

[Michal Gdula-2]

Thank you for your advice!

The price seems to be cheap, but I wander how it works with fluorescence. At
the moment probably I will stay with my vectashield so as to not chang to
many things in one go.

Regards,

Michal Gdula


Subject: Re: Correction of Z-axis distortion- request for opinion
From: Stanislav Vitha <[hidden email]>
Reply-To: Confocal Microscopy List
<[hidden email]>
Date: Sat, 4 Apr 2009 03:58:51 -0500
Content-Type: text/plain

I would also consider switching to a mounting medium with correct refractive
index (=same RI as immersion oil)  2,2-thiodiethanol comes to mind.  See
Staudt, 2007.  A 500 ml bottle can be had for ~$30.

1. Staudt, T., M.C. Lang, R. Medda, J. Engelhardt, and S.W. Hell, 2,2'-
thiodiethanol: a new water soluble mounting medium for high resolution optical
microscopy. Microsc Res Tech, 2007. 70(1): p. 1-9.

Stan Vitha
Microscopy and Imaging Center
Texas A&M University

 

[Mark Cannell]

I'm afraid you do not appreciate the problem. The 1.3 NA objective will
have higher resolution because there will be no aberrations.

Cheers

Michal Gdula wrote:
> Thank you very much for your answer.
> NA 1.3 is smaller than NA 1.4 what means for me lower resolution. So far I will
> need to stay with my oil immersion objective but maybe we will need to
> consider buying this objective in the future.
>
> Greetings
> Michal Gdula
>  

[Guy Cox]

TDE is excellent with fluorescence - it also acts as an antifade.  You
can get exactly the RI you want by adjusting the amount of water in it.
I've used it for the highest resolution micrographs I ever took.  The
one problem is that there are some security restrictions on supplying
it since it is a precursor for mustard gas.  But that just means you
may have to sign some forms.  Do check out the reference Stanislav
sent because it really does seem like the solution to your problem.

From your previous message, it seems likely that Vectashield is probably
not actually the RI you reported, if all is OK in oil.

                                            Guy



Optical Imaging Techniques in Cell Biology
by Guy Cox    CRC Press / Taylor & Francis
    http://www.guycox.com/optical.htm
______________________________________________
Associate Professor Guy Cox, MA, DPhil(Oxon)
Electron Microscope Unit, Madsen Building F09,
University of Sydney, NSW 2006
______________________________________________
Phone [phone]     Fax [phone]
Mobile [phone]
______________________________________________
     http://www.guycox.net
-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Michal Gdula
Sent: Tuesday, 7 April 2009 1:01 AM
To: [hidden email]
Subject: Re: Correction of Z-axis distortion- request for opinion

Thank you for your advice!

The price seems to be cheap, but I wander how it works with fluorescence. At the moment probably I will stay with my vectashield so as to not chang to many things in one go.

Regards,

Michal Gdula


Subject: Re: Correction of Z-axis distortion- request for opinion
From: Stanislav Vitha <[hidden email]>
Reply-To: Confocal Microscopy List
<[hidden email]>
Date: Sat, 4 Apr 2009 03:58:51 -0500
Content-Type: text/plain

I would also consider switching to a mounting medium with correct refractive index (=same RI as immersion oil)  2,2-thiodiethanol comes to mind.  See Staudt, 2007.  A 500 ml bottle can be had for ~$30.

1. Staudt, T., M.C. Lang, R. Medda, J. Engelhardt, and S.W. Hell, 2,2'-
thiodiethanol: a new water soluble mounting medium for high resolution optical microscopy. Microsc Res Tech, 2007. 70(1): p. 1-9.

Stan Vitha
Microscopy and Imaging Center
Texas A&M University

 

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No virus found in this outgoing message.
Checked by AVG.
Version: 7.5.557 / Virus Database: 270.11.43/2043 - Release Date: 6/04/2009 6:22 AM