Temperature dependence of the nonlocal voltage in an Fe/GaAs electrical spin injection device

The nonlocal spin resistance is measured as a function of temperature in a Fe/GaAs spin-injection device. For nonannealed samples that show minority-spin injection, the spin resistance is observed up to room temperature and decays exponentially with temperature at a rate of 0.018\,K$^{-1}$. Post-growth annealing at 440\,K increases the spin signal at low temperatures, but the decay rate also increases to 0.030\,K$^{-1}$. From measurements of the diffusion constant and the spin lifetime in the GaAs channel, we conclude that sample annealing modifies the temperature dependence of the spin transfer efficiency at injection and detection contacts. Surprisingly, the spin transfer efficiency increases in samples that exhibit minority-spin injection.Comment: 10 pages, 4 figure

Isotopic and spin selectivity of H_2 adsorbed in bundles of carbon nanotubes

Due to its large surface area and strongly attractive potential, a bundle of carbon nanotubes is an ideal substrate material for gas storage. In addition, adsorption in nanotubes can be exploited in order to separate the components of a mixture. In this paper, we investigate the preferential adsorption of D_2 versus H_2(isotope selectivity) and of ortho versus para(spin selectivity) molecules confined in the one-dimensional grooves and interstitial channels of carbon nanotube bundles. We perform selectivity calculations in the low coverage regime, neglecting interactions between adsorbate molecules. We find substantial spin selectivity for a range of temperatures up to 100 K, and even greater isotope selectivity for an extended range of temperatures,up to 300 K. This isotope selectivity is consistent with recent experimental data, which exhibit a large difference between the isosteric heats of D_2 and H_2 adsorbed in these bundles.Comment: Paper submitted to Phys.Rev. B; 17 pages, 2 tables, 6 figure

Going beyond the limitations of the non-patient-specific implant in titanium reconstruction of the orbit.

Reconstruction of post traumatic orbital defects has undergone a stepwise evolution following developments in reconstructive materials and surgical techniques. Advances in communication between surgical teams and design technicians have allowed provision of bespoke surgical plates with a high degree of accuracy and surgical relevance in an appropriate timeframe. We present a case series of 41 consecutive patients treated in London and BernBern Switzer between March 2019 and September 2020 with extensive defects reconstructed with patient specific orbital plates. Complexity of fracture was risk adjusted using the Jaquiery scale with one patient (J3), 14 patients (J4), and 26 Patients (J5). Outcome was assessed by accuracy of fit at the surgical margins and was 94.5%. The study group was statistically tested against a previous series by the same group and was statistically different with respect to the case complexity (p<0.001) and accuracy of fit (p<0.001) (Fisher's exact test). Complications included the removal on one plate due to patient choice, with perfect surgical position and resolving diplopia. Only one plate articulation was poor, this mitigated by the size of the defect and the orbital soft tissue swelling which prohibited seating the implant. The patient remains well with acceptable function and satisfactory aesthetics. We present design considerations including the use two part plates, and surgical pearls to achieve predictable placement. We believe that the use of custom plates for reconstruction of Jaquiery 4 and 5 should be considered. We regard this technology as a game changer in surgical management of the complex high risk orbit

Satisfactory response to electroconvulsive therapy in an autistic patient with severe self-injurious behavior

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