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Messages - Jan Stanstrup

106
XCMS / Re: How to export Xset object intensity data?
Are you looking for the peakTable function or am I misunderstanding what you are trying to do?
If you use CAMERA the equivalent function is getPeaklist.

fillpeaks peaks are in @peaks yes.

I would think into is the most common.

I don't think there is a real benchmark available anywhere. Difficult to establish a ground truth. It is always a compromise.
107
XCMS Online / Re: CAMERA annotation
I think the XCMS online people rarely come by here so you might consider contacting them directly: https://xcmsonline.scripps.edu/landing_page.php?pgcontent=contact

As for the annotations the isotope annotation and adducts/fragments are two different steps and the adducts/fragments is the computationally intensive one they seem to have limited.

Of course another option would be using XCMS through R so you have control...
110
XCMS / Re: Inconsistent integration borders in EICs
I think there is a number of newer functions for useful visuals but I have not used them yet.

For the grouping step I have written a function I find useful: http://www.metabolomics-forum.com/index.php?topic=577.msg1789#msg1789

You can also see where peaks where found with that.

I am having some dependency problems with my package so it might be easier to get the function (analyze.xcms.group) directly from: https://github.com/stanstrup/chemhelper/blob/master/R/xcms_helpers.R
111
XCMS / Re: Inconsistent integration borders in EICs
I have no clear idea of what can help this but my first attempts would be integrate=2 and trying matchedfilter. I have had better luck with matchedfilter getting it to integrate noisy data at all.

btw.: how did you get those plots?

Another thing. You are not showing your profparam but be sure to set it to something like "list(step=0.005)". Otherwise fillpeaks might integrate a too wide EIC slice. Another thing to consider here: https://github.com/sneumann/xcms/pull/3
114
Data Standards / Re: xcms - error in row.names
Can you make a minimum reproducible example?
Is the warning from diffreport?
I don't know what it tries to put in the row names. Searching the forum it seems this is an old problem. Best way to get it resolved is to make an example (+ the data) that can be reproduced and post on the xcms github issues page.

The warning however should not be a big deal as it is only about assigning row names. The warning says it simply gives up assigning row names.
115
Other / Introduction to Nutritional Metabolomics
At time of writing there are 6 seats left. Don't miss out!


Content
The course will provide an introduction to the LC-MS based nutritional metabolomics studies, aiming to cover key steps such as study design, sample collection and analysis, data handling methodologies and metabolite identification.

The students will go through common steps in a typical metabolomics study. Therefore, the major focus will be application of various free or commercial tools for data preprocessing, data analysis, and metabolite identification with computer based hands-on training using example datasets that will be provided to the students.

The course will finalize by presentations of reports generated by the students based on a case study.

SCIENCE, NordFOOD and NUGO homepages only. A limit of 16 participants has been set this year.


Learning outcome
The aim of this course is to introduce the students to all phases in a nutritional metabolomics study and to train the student in the use of available tools for data handling. Both targeted and untargeted LC-MS methodologies will be thought, yet major focus of the course is untargeted LC-MS based metabolomics.

After completing the course the students should be able to:

• Evaluate the effect of study design on data handling and interpretation of final outcome
• Suggest the sample type to analyze for a specific research question and propose the relevant sample collection and preparation procedure 
• Understand the basic principles of LC-MS technology
• Carry out data preprocessing on using freely available tools such as MZmine 
• Perform univariate and multivariate analysis on R/MATLAB 
• Interpret the MS/MS spectra by utilizing available tools (e.g. CAMERA, MetFusion, MetFrag) and databases (e.g. HMDB, MassBank, MZCloud)


Teaching and learning methods
Lectures, hands-on exercises, group discussions.


Lecturers
• Lars O. Dragsted
• Gözde Gürdeniz
• Jan Stanstrup
• Rastislav Monosik
• Mads Vendelbo Lind 


Link: https://phdcourses.ku.dk/DetailKursus.aspx?id=102145&sitepath=NAT
116
XCMS / Re: How can I do the processing data? normalization?
First thing to do is ask yourself if you can explain why a sample is different.

Does the loadings give a hint? -->
If all variables are on one side you have systematic sensitivity/concentration issues.
Does sample analysis order help explain?
Is it a well defined group of variables that cause the difference? What are they? Could they be contaminants?


Would you expect that there could be large differences between biological samples (e.g. different humans) or should they be much more similar than between treatments (e.g. different types of wine)?
118
R / Re: DOUBT ABOUT MS^E
I have not tried so I cannot answer definitively but I'd think so. Question is if the software you want to use afterwards understands it. I guess you have two "functions"? You could split those apart with the scanEvent filter. You'd need that filter also to get rid of the lockmass scans.

btw.: I had some MS/MS data today where I used the lockmassRefiner. That seemed to do something wrong. On the other hand it seemed that with my data I got the calibrated data which was not the case with previous versions. So for calibrated data compare with your vendor software to check that the peaks have the right mass.
119
XCMS / Re: How can I do the processing data? normalization?
I am not familiar with the normalization in xcms Online. That seems to be specific to their interface.

The other option is about which values to use. "into" is the area under the peaks, maxo is the height of the peaks. So it is not directly related to normalization I would assume. Just they are on the same tab. Normally you'd use "into".
120
Early-career Members Network (EMN) / 17th Nov WEBINAR: Smarter ways to clean LC-MS data
The EMN's next webinar is tomorrow: Smarter ways to clean LC-MS data: Use of QCs for between- and within-batch signal correction.

Click here to learn more about this latest webinar by Dr. Carl Brunius.

Please register for "Smarter ways to clean LC-MS data: Use of QCs for between- and within-batch signal correction" to be held on November 17th, 2016 11:00 UTC/12:00 BST at: 

https://attendee.gotowebinar.com/register/5575746988123613187

After registering, you will receive a confirmation email with information about joining the webinar.

Brought to you by the EMN of the Metabolomics Society