The reversible transverse relaxation rate, R2', is sensitive to the deoxyhaemoglobin content of brain tissue, enabling information about the oxygen extraction fraction to be obtained. However, R2' is also sensitive to macroscopic magnetic field gradients, particularly at air-tissue interfaces where a large susceptibility difference is present. It is important that this latter effect is minimise...

BACKGROUND Imaging and postmortem studies suggest that frontal lobe white matter (FLWM) volume expands until about the age of 44.6 years and then declines. Postmortem evidence indicates that the structural integrity of myelin sheaths deteriorates during normal aging, especially in late myelinating regions such as the frontal lobes. OBJECTIVES To assess the integrity of FLWM by magnetic resona...

A brief review of spin relaxation (1) in nematogens is given. The usual problems in this area arise from the lack of a good theoretical model and a spin system in which meaningful measurements and direct comparison with the model can be made. The proton and deuteron spin-lattice relaxation in nematics have been extensively studied both theoretically (2,3) and experimentally (4-8). It is general...

We study an electron spin qubit confined in a moving quantum dot (QD), with our attention on both spin relaxation, and the product of spin relaxation, the emitted phonons. We find that Doppler effect leads to several interesting phenomena. In particular, spin relaxation rate peaks when the QD motion is in the transonic regime, which we term a spin relaxation boom in analogy to the classical son...

The spin dynamics of geometrically frustrated pyrochlore antiferromagnets Y2Mo2O7 and Y2Mo1.6Ti0.4O7 have been investigated using muon spin relaxation. In Y2Mo2O7 a dramatic slowing down of the Mo spin fluctuations occurs as one approaches the spin freezing temperature TF of 22 K from above. At lower temperatures the spins freeze into a disordered magnetic state similar to that found in a spin ...

Recent consideration of spin based quantum computation, optical switches, magnetic memory cells, etc. [1] mandates an improved understanding of spin dynamics and, in particular, the spin relaxation rate [2]. The most promising materials for device purposes, III-V and II-VI compounds, have been shown [3] to have spin relaxation rates dominated by the D’yakonov-Perel’ (DP) mechanism at moderate t...

We present La and Cu NMR relaxation measurements in single crystal La1.67Eu0.2Sr0.13CuO4. A strong peak in the La spin-lattice relaxation rate observed in the spin ordered state is well described by the BPP mechanism @Bloembergen, Purcell, and Pound, Phys. Rev. 73, 679 ~1948!# and arises from continuous slowing of electronic spin fluctuations with decreasing temperature; these spin fluctuations...

Introduction/Theory: Molecular imaging is emerging as a potential tool for monitoring treatment response in the management of cancer patients. Recent cell biology as well as oncology research has focused on investigating apoptosis or programmed cell death as a means of measuring these induced effects and detecting response. A hallmark of early stage apoptosis is the externalization of phosphati...