Skip to main content

Show Posts

This section allows you to view all Show Posts made by this member. Note that you can only see Show Posts made in areas you currently have access to.

Messages - Metasaur

1
XCMS Online / Re: Fold Change Calculation in XCMS
Sorry-i can't help with your problem. Is there any chance you could send me the sample data or post to the board? For some reason the data files on the homepage don't contain anything.
This would be of great help to me - Thanks!
2
XCMS Online / 0 bytes in sample data file and trouble converting excel
Hi Ralf,

XCMS looks pretty outstanding and I can't wait to use it. Congratulations on y'all's work.

I am just getting started using XCMS and am trying to find the best way to get started. For some reason, every time I try to download the pepsi cola data set, it indicates that 0 bytes were contained in the download file.

I'd skip this step, however, I was trying to get an idea of what the input data set should look like.  I'm trying to find a way to convert the raw data that I have now that has peak areas contained within an excel spreadsheet. Based on what I've read the conversion formats seem to be from data output from GC/MS or LC/MS etc. But I did not carry out the tests myself I simply got a .xls spreadsheet of the results from LC/MS.

What do you think could cause the sample data not to work properly and how do I go about changing my excel spreadsheet into an acceptable input form?

Thanks,
metasaur
3
Sample preparation / Thoughts on types of anti-coagulant used in blood plasma
Hi friends,

Working on a baseline study at the time compaing metabolites in different types of samples such as serum, urine, plasma, and feces. 

Does anyone have suggestions on literature or preference as far as anti-coagulants effecting the results of metabolite concentrations.  At the time being EDTA is looking like the more prominent source however in the clinical setting lithium heparin is used also sodium heparin.  What are y'alls experiences in that regard.

Also is it almost a complete waste to run plasma for comparison reasons.  It seems to me like while it is reproducible, the background noise is high and the concentration compared to serum is much lower almost losing out on roughly 20 metabolites in a GC/MS platform.

Any thoughts would be greatly appreciated.