We compared overexpression of the magnetotactic bacterial gene MagA with the modified mammalian ferritin genes HF + LF, in which both heavy and light subunits lack iron response elements. Whereas both expression systems have been proposed for use in non-invasive, magnetic resonance (MR) reporter gene expression, limited information is available regarding their relative potential for providing g...

We present a detailed description of spin injection and detection in Fe/AlxGa1−xAs/GaAs heterostructures for temperatures from 2 to 295 K. Measurements of the steady-state spin polarization in the semiconductor indicate three temperature regimes for spin transport and relaxation. At temperatures below 70 K, spinpolarized electrons injected into quantum well structures form excitons, and the spi...

(15)N relaxation dispersion experiments were applied to the isolated N-terminal SH3 domain of the Drosophila protein drk (drkN SH3) to study microsecond to second time scale exchange processes. The drkN SH3 domain exists in equilibrium between folded (F(exch)) and unfolded (U(exch)) states under nondenaturing conditions in a ratio of 2:1 at 20 degrees C, with an average exchange rate constant, ...

Triplet-singlet spin relaxation in a vertical electrostatic quantum dot containing two interacting electrons is studied with a realistic model that includes the effects of finite thickness and screening. The spin relaxation mechanism is taken to be spin mixing via the part of the Dresselhaus Hamiltonian that is linear in the lateral momentum. The electron-electron interaction enhances relaxatio...

Muon spin relaxation experiments have been performed in the pyrochlore iridate Pr2Ir2O7 for temperatures in the range 0.025– 250 K. Kubo-Toyabe relaxation functions are observed up to & 200 K, indicating static magnetism over this temperature range. The T → 0 static muon spin relaxation rate ∆(0) ≈ 8 μs implies a weak quasistatic moment (∼0.1μB). The temperature dependence of ∆ is highly non-me...

We develop a theory of effects of electron-electron collisions on the Dyakonov-Perel’ spin relaxation in multi-valley quantum wells. It is shown that the electron-electron scattering rate which governs the spin relaxation is different from that in a single-valley system. The theory is applied to Si/SiGe (001)-grown quantum wells where two valleys are simultaneously populated by free carriers. T...

We perform a comparative study of the spin relaxation by spin-orbit coupling induced from adatoms (hydrogen and fluorine) in graphene. Two methods are applied, giving consistent results: a full quantum transport simulation of a graphene nanoribbon, and a T-matrix calculation using Green’s functions for a single adatom in graphene. For hydrogenated graphene the dominant spinorbit term for spin r...

A new limit is presented on the axionlike monopole-dipole coupling in a range 10 − 1 cm. The gradient of spin-dependent nucleon-nucleon potential between He nucleus and nucleons of the walls of the cell containing He should affect the spin relaxation rate. The limit is obtained from existing data on the relaxation rate of spin-polarized He. PACS: 14.80.Mz; 12.20.Fv; 29.90.+r; 33.25.+k

Introduction: Many MRI techniques are now capable of imaging cells that have been labelled with super-paramagnetic iron oxide (SPIO) [1], and these techniques will be of great benefit to the developing field of cellular therapy. However, the majority of these techniques are not capable of providing quantitative information about cellular density at high iron concentrations, which is critical to...