Just a quick point: check back to see what the gradient levels should be in G/cm and make sure you use the gzcal for your system to get the gzlvl you should use.. On our systems gzcal is roughly 0.2, so where a Lewis Kay sequence calls for a 29.4 G/cm gradient, and uses a gzlvl of 29400, we need to use 14600. We'd been using a couple of sequences with gzlvls of 29400 at one point when our gradient coil got fried: I was told we were using gradients that were too high, so ever since then I make sure to go back to the original publications to find the strength in G/cm.
Tara
________________________________________
From: DeRose, Eugene (NIH/NIEHS) [C] [derose_at_niehs.nih.gov]
Sent: Monday, January 06, 2014 1:34 PM
To: Kirk Marat; ammrl_at_ammrl.org
Subject: Re: AMMRL: BioPack gNcpmgex_NH experiment
Hi Kirk,
This experiment was originally written by Frans Mulder in Lewis Kay's
group. Upon comparing the parameters from the original experiment
(N15_CPMG_Rex_NH2_fm_500_v2) with the BioPack parameters, I noticed that
the gradient levels gzlvl5, gzlvl8 and gzlvl11 do not agree. The correct
values from the original experiment should be gzlvl5=-6000, gzlvl8=15000,
and gzlvl11=29400. I hope this helps.
Best regards,
Eugene
Eugene DeRose, Ph.D.
NIEHS NMR Laboratory Manager
Contractor to NIEHS/DIR
919.541.1981
derose_at_niehs.nih.gov
On 1/3/14 4:25 PM, "Kirk Marat" <Kirk.Marat_at_umanitoba.ca> wrote:
>Happy New Year everyone.
>
>Has anyone had any experience with the N15 T2 exchange experiment
>(gNcpmgex_NH) in BioPack? We can't seem to get it to work or even see
>any signal in the first increment, even when the number of CPMG cycles is
>very low. Other BioPack sequences seem to work fine, suggesting that the
>probe calibration file is fine. Checking on the SPINSIGHTS site, it
>appears that at least one other person has had trouble with this
>experiment (in both VJ 3.2 and 4), but there was no real fix that I could
>see.
>
>This is an INOVA600 running VnmrJ 3.2A.
>
>Thanks!
>Kirk
>
>Kirk Marat, Ph. D. NMR Facility Manager
>Dept. of Chemistry, University of Manitoba
>Winnipeg, Manitoba
>R3T 2N2, Canada
>
>Ph: (204) 474-6259 FAX: (204) 474-7608
>
>
Received on Tue Jan 07 2014 - 08:44:05 MST