Posted by bish0173 on May 7, 2008 10:37 PM|Permalink
Comments
Hi Craig, I just have a few questions about the paper you presented on. For the CARS imaging, they used the CH2 vibration at 2845 cm^-1 to identify lipids. Is this vibration specific to lipids or do other biomolecules in the sample also exhibit it? Could this be a contributor to the background? Could you look at several different vibrations and correlate them spatially to more accurately determine lipids?
Thanks, Greg, I have the same question with you. Craig, with only one vibration wavelength, I don't think the data is reliable. Do they mention to use multiple vibrations?
Greg, the CH2 vibration would not be specific to just lipids, any biomolecule with a CH2 vibration (i.e., a lysine residue) would give a CARS signal. I'm assuming that is the main source of background noise within the images.
In regard to Edgar's questions, a voxel is a 3D pixel. It represents the volume function of a pixel which incorporates the z-axis.
Also, for number three, confocal microscopes are superior to CARS in resolution for both (x,y) and z axis
In response to Greg's question (as well as Meng an Nic's follow up questions/comments), yes the use of only one wavelength may be problematic and is the major source of the background in the CARS images. More vibrational levels could be used, but for the purposes of this study, the high density of CH2 groups in the lipids were sufficient for their measurements.
Josh is also correct in that CARS has inferior resolution in all planes versus confocal (1 um vs .5 um for xy and .3 um vs .25 um for z)
The benefits of CARS are seen in the low noise level and label free nature as well as not being affected by the matrix to the degree that confocal images are.
The instrument used for the study was a forward CARS instrument
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Comments
Hi Craig, I just have a few questions about the paper you presented on. For the CARS imaging, they used the CH2 vibration at 2845 cm^-1 to identify lipids. Is this vibration specific to lipids or do other biomolecules in the sample also exhibit it? Could this be a contributor to the background? Could you look at several different vibrations and correlate them spatially to more accurately determine lipids?
Posted by: Greg Wolken | May 8, 2008 09:50 AM
Thanks, Greg, I have the same question with you. Craig, with only one vibration wavelength, I don't think the data is reliable. Do they mention to use multiple vibrations?
Posted by: Meng Jing | May 8, 2008 10:29 AM
There are a couple of concepts that we need to explore further...
1. What is a voxel?
2. Did they use epi or forward CARS in the paper? What would have been on the observed background?
3. How does the (x,y) and z resolutions compare between CARS and Confocal microscopes?
Posted by: Edgar Arriaga | May 8, 2008 04:02 PM
Greg, the CH2 vibration would not be specific to just lipids, any biomolecule with a CH2 vibration (i.e., a lysine residue) would give a CARS signal. I'm assuming that is the main source of background noise within the images.
Posted by: Nic Frost | May 9, 2008 02:21 PM
In regard to Edgar's questions, a voxel is a 3D pixel. It represents the volume function of a pixel which incorporates the z-axis.
Also, for number three, confocal microscopes are superior to CARS in resolution for both (x,y) and z axis
Posted by: Josh Ochocki | May 9, 2008 02:49 PM
In response to Greg's question (as well as Meng an Nic's follow up questions/comments), yes the use of only one wavelength may be problematic and is the major source of the background in the CARS images. More vibrational levels could be used, but for the purposes of this study, the high density of CH2 groups in the lipids were sufficient for their measurements.
Josh is also correct in that CARS has inferior resolution in all planes versus confocal (1 um vs .5 um for xy and .3 um vs .25 um for z)
The benefits of CARS are seen in the low noise level and label free nature as well as not being affected by the matrix to the degree that confocal images are.
The instrument used for the study was a forward CARS instrument
Posted by: Craig Bishop | May 9, 2008 07:29 PM