Biomedical Tracers Spin Labels by CpA177

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									Spin Labels (ESR, NMR)
Electron Spin Resonance (ESR), Nuclear
Magnetic Resonance (NMR), & Magnetic
Resonance Imaging (MRI) are covered in
Guy & ffytche, An Introduction to The
Principles of Medical Imaging, Imperial
College Press, 2000, Chapter 2, pp 78-88,
& Chapter 6, pp 199-264.
Other coverage is also found in Smith,
Shung, & Mosher, Chapter 4, Magnetic
resonance imaging, in Shung, Smith, Tsui,
Principles of Medical Imaging, Academic
Press, 1992, pp 213-271.
Electronic Quantum Spin
Electrons usually occupy electronic shells in
atoms as pairs. In such pairs the electrons have
spins opposite one another so the associated
magnetic fields cancel. In some ions, free
radicals or paramagnetic materials, however, a
single electron may occupy an orbital. Placing
such an atom into a strong magnetic field will
tend to cause the electrons to align with the field.
Adding radiofrequency energy to the system in
this situation can cause the electron spins to
“flip” so they oppose the magnetic field. This
energy absorption can be detected by monitoring
the energy input as radiofrequencies are
scanned.
 ESR Theory:
 http://www.pharmainfo.net/reviews/electron-spin-
 resonance-esr-principle-theory-and-applications
http://www.uottawa.ca/publications/
interscientia/inter.2/spin.html

 http://hyperphysics.phy-
 astr.gsu.edu/hbase/molecule/esr.html




ESR Illustrated:
http://www.physics.montana.edu/eprlab/nBody_2.htm
ESR Spectral Information

Because the exact energy absorption frequency of
the unpaired electrons are sensitive to their
molecular surroundings, the ESR spectra provide
information on the nature of these surroundings.
This is provided both by the position of major
absorbance frequencies & by the splitting of these
absorbances into hyperfine spectral features.
While a free radical might have a characteristic ESR
spectrum as a pure isolated entity, it may
demonstrate specific spectral features when placed
into a particular solvent or biological system.
                           Trace levels of Mn2+ ions
                           in dolomite, CaMg(CO3)2




http://www.chem.memphis.edu/faculty/lloyd/lloyd.htm
 NMR Spectoscopy
Similar to electrons, protons may also
demonstrate quantal spins. If there are odd
numbers of protons in the nucleus, the nucleus
will demonstrate a nuclear magnetic moment
capable of perturbation by radiofrequencies
when in the presence of a strong external
magnetic field. Here, however, the absorbed
energy can be sensed either by the irradiating
circuit or by a field coil as the nuclei flip back to
their ground states. Again, resonant energy
levels are characteristic of the nuclei involved
& the molecular environment surrounding
these nuclei.
Nuclei demonstrating accessible signals
include: 1H, 13C, 17O, 19F, 23Na, 31P
NMR Basics:
  http://www.cis.rit.edu/htbooks/nmr/
  http://www.nobel.se/chemistry/ed
   ucational/poster/1991/nmr.html
 http://www.wpi.edu/Academics/Depts/
 Chemistry/Courses/CH2670/nmr.html
http://www.brynmawr.edu/Acads/Chem/mnerzsto/The_B
asics_Nuclear_Magnetic_Resonance%20_Spectroscop
y_2.htm
NMR Software:
 http://www.spincore.com/nmrinfo/software_s.html
Basic Instrumental Layout for NMR




  http://sis.bris.ac.uk/~sd9319/spec/nmrspec.jpg
NMR Theory:
http://www.ipfw.edu/chem/262/262spring03/262nt0311.htm

http://www.shu.ac.uk/schools/sci/
chem/tutorials/molspec/nmr1.htm

http://www.nuclear-magnetic-resonance.com/node4.html

http://www.shef.ac.uk/chemistry/crystal/projects-
ug/sillitoe/html/theory.htm

http://www.resonancepub.com/magres.htm

http://www.avogadro.co.uk/analysis/nmr/nmr.htm

Structural determination of proteins by NMR:
http://www.cryst.bbk.ac.uk/PPS2/projects/schirra/html/
home.htm
MRI Analysis
Magnetic Resonance Imaging (MRI) is the
extrapolation of NMR to multiple
dimensions. It extracts information on
relative composition of body areas by
assessing the strength & resonant
frequency (& thus the chemical nature of
absorbing molecules) of the NMR signals
as part of a 3 or 4 dimensional evaluation
of objects tested. The computationally
intensive evaluation of MRI data sorts the
vast volume of information collected
during a scan & presents it in the form of
an image that includes intensity data.
MRI basics:
http://www.mritutor.org/mritutor/
http://health.howstuffworks.com/mri2.htm

 http://www.refindia.net/rlinks/reviewedlinks/mri.htm



 MRI instrumentation:
 http://info.med.yale.edu/intmed/cardio
 /imaging/techniques/mri_diagram/
Medical applications:
http://www.gentili.net/diabeticfoot/mri.htm

MRI analysis:
http://www.cis.rit.edu/research/thesis/
bs/1998/fetzner/Thesis_TF_thesis.html


MRI contrast agents:
http://www.mritutor.org/mritutor/contrast.htm
http://www.mr-tip.com/serv1.php?type=coa
http://adsabs.harvard.edu/abs/2008mcpp.book..157B
         New Developments & Frontiers
Long Range NMR/MRI
Glover&BowtellMRIridesthewaveNature457n7232p971
BrunneretalTravelingwaveNMRNature457n7232p994
LongRangeNMRNMeth6p248
Intracellular NMR & MRI
Midgley&Borkowski2009ElectronTomography&Holographynmat
2406
Burz&Shekhtman2009InsidetheLivingCellNature458n7234p37
Hammel2009NanoscaleMRINatureCom458p844
InomataEtAl2009HighResolutionMultiDimensionalNMRSpectros
copyOfProteinsInHumanCellsNature458p106
SakakibaraEtAl2009ProteinStructureDeterminationInLivingCells
ByInCellNMRSpectroscopyNature458p07814

								
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