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Lithium is widely used in psychotherapy. The (6)Li isotope has a long intrinsic longitudinal relaxation time T(1) on the order of minutes, making it an ideal candidate for hyperpolarization experiments. In the present study we demonstrated that lithium-6 can be readily hyperpolarized within 30 min, while retaining a long polarization decay time on the order of a minute. We used the intrinsically long relaxation time for the detection of 500 nM contrast agent in vitro. Hyperpolarized lithium-6 was administered to the rat and its signal retained a decay time on the order of 70 sec in vivo. Localization experiments imply that the lithium signal originated from within the brain and that it was detectable up to 5 min after administration. We conclude that the detection of submicromolar contrast agents using hyperpolarized NMR nuclei such as (6)Li may provide a novel avenue for molecular imaging.

New low-temperature inserts compatible with an existing hyperpolarizer were developed to dynamically polarize nuclei in large samples. The performance of the system was tested on 8 ml glassy frozen solutions containing 13C-labeled molecules and doped with nitroxyl free radicals. The obtained 13C low-temperature polarization was comparable to the one measured on 20 times smaller sample volume with only 3–4 times higher microwave power. By using a dissolution insert that fits to the new design, it was possible to obtain about 120 ml of room-temperature hyperpolarized solution. The polarization as well as the molecule concentration was comparable to the values obtained in standard size hyperpolarized samples. Such large samples are interesting for future studies on larger animals and possibly for potential clinical applications.

Until recently the main application of dynamic nuclear polarization techniques has been in nuclear and particle physics, where they are used to polarize nuclei in bulk matter to be employed as polarized solid targets for particle beams probing the spin dependence of nuclear interactions. These techniques have now become most promising for applications in biomedical magnetic resonance and the knowledge gained in forty years of target development becomes of immediate interest.

The potential of RF-magnetron sputtering to achieve high quality Cu(In,Ga)Se2 (CIGS) thin films and efficient solar cells with the goal of using a single technique for all solar cell processing steps is explored. The end point detection method was adapted to RF-magnetron deposition of CIGS in two- or three stages sputtering process. It allows the control of the final composition of the deposited layers in a reproducible way. The influence of substrate temperature and Ar pressure during the deposition on the surface and crossectional morphology of CIGS films was studied for two and three-stage sputtering process sequence. The solar cells prepared with films deposited by two-stage sputtering nave showed a better performance with maximum efficiency above 8 %.

The increase of total choline in tumors has become an important biomarker in cancer diagnosis. Choline and choline metabolites can be measured in vivo and in vitro using multinuclear MRS. Recent in vivo(13)C MRS studies using labeled substrates enhanced via dynamic nuclear polarization demonstrated the tremendous potential of hyperpolarization for real-time metabolic studies. The present study demonstrates the feasibility of detecting hyperpolarized (15)N labeled choline in vivo in a rat head at 9.4 T. We furthermore report the in vitro (172 +/- 16 s) and in vivo (126 +/- 15 s) longitudinal relaxation times. We conclude that with appropriate infusion protocols it is feasible to detect hyperpolarized (15)N labeled choline in live animals.

Apart from their very classical use to build polarized targets for particle physics, the methods of dynamic nuclear polarization (DNP) have more recently found application for sensitivity enhancement in high-resolution NMR, both in the solid and in the liquid state. It is often thought that the possible signal enhancement in such applications deteriorates when the DNP is performed at higher fields. We show that for a dissolution-DNP method that uses conventional (2,2,6,6-tetramethylpiperidine 1-oxyl) radicals as the paramagnetic agent, this is not the case for fields up to 5 T.

The methods of dynamically polarizing nuclei (DNP) have not only lead to the development of increasingly sophisticated polarized targets with which the role of spin in nuclear and particle interactions is investigated, but have also opened new possibilities in neutron science by exploiting the strong spin dependence of the neutron scattering. Very recently NMR and MRI have been a driving force behind a surge of interest in DNP methods, considering its tremendous potential for sensitivity enhancement. An overview of our current projects with dynamically polarized nuclei is given.

Polycrystalline thin-film CdTe/CdS solar cells have been developed in a configuration in which a transparent conducting layer of indium tin oxide (ITO) has been used for the first time as a back electrical contact on p-CdTe. Solar cells of 7·9% efficiency were developed on SnOx:F-coated glass substrates with a low-temperature (

In recent years methods of creating 'hyperpolarized' substances have gained considerable attention in biomedical magnetic resonance and dynamic nuclear polarization (DNP) is one of the most promising, especially for imaging applications. Here we present results of DNP studies on protons and C-13 nuclei in frozen solutions of sodium acetate and glycine, dissolved in water-ethanol and water-glycerol, doped with TEMPO free radicals and EHBA-Cr-V complexes. Up to 14% C-13 polarization and close to 50% proton polarization were achieved at similar to 1.2K in a magnetic field of similar to 3.5 T under irradiation with similar to 97 GHz microwaves, which corresponds to an enhancement of more than 15 000 with respect to thermal equilibrium polarization in a 9.4 T magnet at room temperature. For all investigated samples the main DNP mechanism was found to be thermal mixing. The absolute polarization values achieved are mainly depending on the type of solvent, the water-alcohol ratio, its degree of deuteration and the concentration of paramagnetic centres. This allows application of the so-established sample preparation and DNP procedure to other molecules in future experiments. Two further examples of DNP of molecules in solution underline the general applicability of the method to a wide variety of organic compounds.

For most of the last forty years, the techniques of Dynamic Nuclear Polarization (DNP) have been confined to particle-physics laboratories building polarized targets, but recently it has been shown that samples similar to a solid target can be transformed into room temperature liquid solutions while retaining a high nuclear polarization. This method of "hyperpolarization" is of interest in NMR/MRI/MRS. We describe a 3.35 T DNP/9.4 T MRI installation based on a continuous-flow cryostat, using a standard wide-bore low-field NMR magnet as prepolarizer magnet and a widely available radical as polarizing agent. The interfacing to a rodent scanner requires that the infusion of the polarized solution in the animal be remotely controlled, because of limited access inside the magnet bore. Physiological constraints on the infusion rate can be a serious source of polarization loss, and the discussion of efficiency is therefore limited to that of the prepolarizer itself, i.e., the spin temperatures obtained in the solid state. To put our results in context, we summarize data obtained in targets with different types of radicals, and provide a short review of the DNP mechanisms needed in their discussion. (C) 2007 Wiley Periodicals, Inc.