Comparative optical investigations on the one-dimensional organic metals (perylene)2(PF6)1.1x0.8CH2Cl2, (pyrene)12(SbF6)7 and fluoranthene)2(AsF6)0.2(PF6)0.8

The reflectance spectra of different radical cation salts of the type (arene)2XF6 are reported (X=P, As, Sb). For light polarised perpendicular to the molecular stacks, the crystals exhibit the optical behaviour of an insulating molecular crystal, whereas for light polarised parallel to the stacks a pronounced plasma edge is observed. Compared to other organic metals the crystals show remarkably high values of the plasma energy. Because the concentration of the free carriers is obtained from the charge transfer between the radical cations and the inorganic counter ions, the effective mass of the free carriers may be calculated from the plasma frequency. The analysis of the reflectance data by a Lorentz-Drude model yields as well the values of the mean collition time, the electrical conductivity, and the bandwith

Plasma reflectance of the one-dimensional organic metals of the type (arene)2XF6(arene=perylene, pyrene or fluoranthene &#59; X=P, As, Sb)

We have investigated the spectral position and the form of the plasma edge of different radical cation salts of the type (arene)zXF, independence of the type of the organic donor molecule, and of the charge transfer between donor and acceptor molecules

Estimation of return-to-sports-time for athletes with stress fracture – an approach combining risk level of fracture site with severity based on imaging

<p>Abstract</p> <p>Background</p> <p>The aim was to compare the return-to-sports-time (RTST) following stress fractures on the basis of site and severity of injury. This retrospective study was set up at a single institution. Diagnosis was confirmed by an interdisciplinary adjudication panel and images were rated in a blinded-read setting.</p> <p>Methods</p> <p>52 athletes (female, n = 30; male, n = 22; mean age, 22.8 years) with stress fracture (SFX) who had undergone at least one examination, either MRI or bone scintigraphy, were included. Magnetic resonance images (MRI) and/or bone scintigraphy (BS) of SFX were classified as either low- or high-grade SFX, according to existing grading systems. For MRI, high-grade SFX was defined as visibility of a fracture line or bone marrow edema in T1-, T2-weighted and short tau inversion recovery (STIR) sequences, with low-grade SFX showing no fracture line and bone marrow edema only in STIR and/or T2-weighted sequences. In BS images, a mild and poorly defined focal tracer uptake represented a low-grade lesion, whereas an intense and sharply marginated uptake marked a high-grade SFX. In addition, all injuries were categorized by location as high- or low-risk stress fractures. RTST was obtained from the clinical records. All patients were treated according to a non-weight-bearing treatment plan and comprehensive follow-up data was complete until full recovery. Two-sided Wilcoxon’s rank sum test was used for group comparisons.</p> <p>Results</p> <p>High-risk SFX had a mean RTST of 132 days (d) [IQR 64d – 132d] compared to 119d [IQR 50d – 110d] for low-risk sites (p = 0.19). RTST was significantly longer (p = 0.01) in high-grade lesions [mean, 143d; IQR 66d – 134d] than in low-grade [mean, 95d; IQR 42d – 94d]. Analysis of high-risk SFX showed no difference in RTST (p = 0.45) between high- and low-grade [mean, 131d; IQR 72d – 123d vs. mean, 135d; IQR 63d – 132d]. In contrast, the difference was significant for low-risk SFX (p = 0.005) [low-grade; mean, 61d; IQR 35d – 78d vs. high-grade; mean, 153d; IQR 64d – 164d].</p> <p>Conclusion</p> <p>For SFX at low-risk sites, the significant difference in RTST between low- and high-grade lesions allows more accurate estimation of RTST by this approach. Both location of the injury and severity determined by imaging should therefore be considered for prediction of RTST.</p