th  - 1988 - 51st ENC Conference

27 1 COLLECTION OF PHOSPHORUS-31 NMR SPECTRA FROM RAT
PUPS WITH INDUCED HYPERTHERMIA: Joseph J. Ford*, Katherine H. Taber
and R. Nick Bryan, Baylor Magnetic Resonance Center, Houston, Texas 77030
It is well known that hyperthermia in young animals will induce
seizures, which involve the expenditure of a large amount of energy, and
eventually death. Phosphorous-31 NMR can be used to monitor how seizures
affect the levels of the high energy phosphorous metabolites. Measuring the
phosphorous-31 NMR spectrum on a young, 5-20 day old, rat pup while
inducing hyperthermia and monitoring the EEG presents a technical challenge.
To collect the data, it was necessary to physically restrain the animal to
insure that anesthetics not affect the results. There is very little free space
inside the probe that is placed in the NMR magnet and the probe is at least 1
foot inside the narrow (70 mm) cylinder of the NMR magnet. It was
necessary to gently restrain the animal in this isolated, high magnetic field
enviroment, while monitoring the EEG and internal body temperature, and
adjusting the body temperature. A specially designed water blanket and a
commercial thermocouple probe were used to monitor and maintain body
temperture and the use of long lead electrodes enabled the collection of some
EEG data while the animal was in the magnet. Evaluation of the equipment
and techniques used will also be presented.
-- 28 I HIGH PRESSURE DEUTERIUM SOLID STATE NMR OF POLYCRYSTALLINE CdPS 3
I INTERCALATED WITH PYRIDINE: P. L. McDaniel, G. Liu and J. Jonas, University of
Illinois, Urbana, IL 61801
O O
The use of the quadrupole echo sequence (90 -T-90 ) for the collection of
• X. .
deuterium powder pattern lineshapes which provzde inform~tzon about the dynamcs of
the deuterated molecule is well known. We have applied this technique to the study
of ds-pyridine intercalated into the VDW gap of the lamellar CdPS 3 host. Furthermore,
we d~veloped a probe which allows us to study this system at pressures up to 4.5 kbar.
Pressure experiments were performed for four isotherms, (270K, 300K, 330K and
360K). Due to the absence of any large amplitude reorientational motion at 270K,
pressure had a minimal effect on the lineshape. At 300K, 330K and 360K, however,
increasing pressure results in a decrease in the VDW gap size which in turn has a
marked effect on the reorienting pyridine molecule. Increasing pressure results in
a reduction of the proportion of motionally reduced pyridine (a result of rapid
reorientational motion of 3-fold or higher symmetry about an in-plane axis perpendi-
cular to the molecular C 2 symmetry axis) to the rigid pyridine component.
These high pressure deuteDium solid state NMR experiments show that an elevation
in pressure produces lineshapes similar to those obtained with a decrease in
temperature. These two methods of affecting intercalate dynamics are basically very
different. Thermal expansion of the host material resulting in a larger VDW gap would
be small. The application of pressure, however, results in an actual alteration of
the VDW gap dimension. The use of high pressure to generate changes in the VDW gap
could be useful in the simulation of the effect on intercalated molecules of similar
host compounds whose differences lie only in their VDW gap size.
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