The ability to control chemical and physical structuring at the nanometre scale is important for developing high-performance thermoelectric materials. Progress in this area has been achieved mainly by enhancing phonon scattering and consequently decreasing the thermal conductivity of the lattice through the design of either interface structures at nanometre or mesoscopic length scales or multiscale hierarchical architectures. A nanostructuring approach that enables electron transport as well as phonon transport to be manipulated could potentially lead to further enhancements in thermoelectric performance. Here we show that by embedding nanoparticles of a soft magnetic material in a thermoelectric matrix we achieve dual control of phonon- and electron-transport properties. The properties of the nanoparticles-in particular, their superparamagnetic behaviour (in which the nanoparticles can be magnetized similarly to a paramagnet under an external magnetic field)-lead to three kinds of thermoelectromagnetic effect: charge transfer from the magnetic inclusions to the matrix; multiple scattering of electrons by superparamagnetic fluctuations; and enhanced phonon scattering as a result of both the magnetic fluctuations and the nanostructures themselves. We show that together these effects can effectively manipulate electron and phonon transport at nanometre and mesoscopic length scales and thereby improve the thermoelectric performance of the resulting nanocomposites.

Superparamagnetic Fe3O4 nanoparticles remarkably enhance the room-temperature thermoelectric and cooling performance of BiSbTe alloys.

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Superparamagnetic Ni nanoparticles remarkably enhance the room-temperature thermoelectric and cooling performance of n-type BiTeSe alloys.

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The macrophage-rich core of advanced human atheroma has been demonstrated to be hypoxic, which may have implications in plaque stability. The goal of this study was to determine the feasibility of the hypoxia PET imaging agent 64 Cu-ATSM to detect hypoxia in a rabbit model of atherosclerosis imaged on a simultaneous PET/MR scanner, using MR for both attenuation correction and depiction of lesion location. Methods: New Zealand White rabbits fed a Western diet for 4-6 wk underwent endothelial denudation of the right femoral artery by air desiccation to induce an atherosclerotic-like lesion and underwent a sham operation on the left femoral artery. Four and 8 wk after injury, a 0-to 60-min dynamic whole-body PET/MR examination was performed after injection of approximately 111 MBq of 64 Cu-ATSM. After 24 h, a 0-to 75-min dynamic PET/MR examination after injection of approximately 111 MBq of 18 F-FDG was performed. The rabbits were euthanized, and the injured femoral artery (IF) and sham-operated femoral artery (SF) were collected for immunohistochemistry assessment of hypoxic macrophages (hypoxia marker pimonidazole, macrophage marker RAM-11, and hypoxia-inducible factor-1 α subunit ). Regions of interest of IF, SF, and background muscle (BM) were drawn on fused PET/MR images, and IF-to-BM and SF-to-BM SUV ratios were compared using the Student t test. Results: Elevated uptake of 64 Cu-ATSM was found in the rabbits' IF compared with the SF. 64 Cu-ATSM imaging demonstrated IF-to-SF SUV mean ratios (±SD) of 1.75 ± 0.21 and 2.30 ± 0.26 at 4 and 8 wk after injury, respectively. 18 F-FDG imaging demonstrated IF-to-SF SUV mean ratios of 1.84 ± 0.12 at 8 wk after injury. IF-to-BM SUV mean ratios were significantly higher (P , 0.001) than SF-to-BM SUV mean ratios both 4 and 8 wk after injury for 64 Cu-ATSM and 8 wk after injury for 18 F-FDG (P , 0.05). Pimonidazole immunohistochemistry at 8 wk colocalized to RAM-11 and HIF-1α. Conclusion: The results show that hypoxia is present in this rabbit model of atherosclerosis and suggest that 64 Cu-ATSM PET/MR is a potentially promising method for the detection of hypoxic and potentially vulnerable atherosclerotic plaque in human subjects. At herosclerosis is a systemic degenerative and inflammatory vascular disease that develops over decades, leading to advanced lesions characterized by a lipid core separated from the lumen by a fibrous cap. It has been recognized that plaque composition more than the degree of luminal stenosis determines the risk of acute clinical events (e.g., stroke, myocardial infarction) (1). Macrophage-rich plaques with a thin fibrous cap, large lipid core, and abundance of leaky microvessels tend to be more vulnerable (1). The rupture or erosion of the fibrous cap in vulnerable plaque may lead to thromboembolization and arterial occlusion (2,3).According to the anoxemia theory of atherosclerosis, an imbalance between the demand for and supply of oxygen in the arterial wall is a key factor in the development of atherosclerotic lesions (4). In the initial s...

A single gold nanopore with high surface enhanced Raman spectroscopy (SERS) activity is fabricated on the tip of a glass nanopipette.