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Osteoarthritis (OA) of the hip and knee joint is a common disease worldwide and is associated with chronic disability and progressive pain. Currently, themost suitable treatment method in end-stage OA is surgical restoration by total joint replacement (TJR). In this regard, patients suffering from end-stage OA and waiting forTJR intervention are also affected by extensively impaired skeletal muscle health. This is characterized by progressive muscle atrophy, strength decline and associated deficits in neuromuscular activation. Unfortunately the importance of skeletal muscle health, as a predictor for a successful muscular and functional recovery, is clinically underrepresented in medical indication and preoperative diagnostics. Therefore, this review aims to describe patients pre, peri and postoperative muscle health during the whole process of aTJR intervention. Additionally, underlying mechanisms and potential perioperative stressors, which may be responsible for impaired muscular physiology after TJR, will be described. As a second purpose, this review illustrates the potential impact of preoperative exercise interventions by challenging the better in, better out approach in TJR therapy. KEY WORDS: Muscle Atrophy, Total Knee Arthroplasty, Total Hip Arthroplasty, Preoperative Intervention, Arthrogenic Muscle Inhibition

Research was conducted to examine the electro-optical characteristics of (Zn,Cd)Se/Zn(S,Se) quantum well structures grown on GaAs substrates using differential electroabsorption spectroscopy at room temperature and compared to model calculations. It was shown that the 20 nm (Zn,Cd)Se layer behaved like a three-dimensional system. Results were identified as typical Franz-Keldysh oscillations.

This study reports a method to reuse GaAs substrates with a batch process for thin film light emitting diode (TF-LED) production. The method is based on an epitaxial lift-off technique. With the developed reclaim process, it is possible to get an epi-ready GaAs surface without additional time-consuming and expensive grinding/polishing processes. The reclaim and regrowth process was investigated with a one layer epitaxial test structure. The GaAs surface was characterized by an atomic force microscope directly after the reclaim process. The crystal structure of the regrown In0.5(Ga0.45Al0.55)0.5P (Q55) layer was investigated by high resolution x-ray diffraction and scanning transmission electron microscopy. In addition, a complete TF-LED grown on reclaimed GaAs substrates was electro-optically characterized on wafer level. The crystal structure of the epitaxial layers and the performance of the TF-LED grown on reclaimed substrates are not influenced by the developed reclaim process. This process would result in reducing costs for LEDs and reducing much arsenic waste for the benefit of a green semiconductor production. [ABSTRACT FROM AUTHOR]

A study was conducted on the picosecond lasing characteristics of multiple quantum well lasers based on (Zn,Cd)Se/Zn(S,Se)/(Zn,Mg)(S,Se). The spectral and temporal changes of the lasers' emissions at 2 K were examined after picosecond optical excitation. Ultrahigh-frequency oscillations of up to 100 GHz were exhibited by the lasers when pumped above the threshold. The oscillations are attributed to the multimode emission resulting from the superposition of higher lateral modes and longitudinal ground modes.

We investigate optoelectronic properties of monolithically stacked diode lasers, so-called Nanostack® devices that include two nominally identical waveguide segments separated by a specially designed tunnel junction. Near-field optical microscopy provides straightforward and separate access to the properties of both optically active segments. Device emission, namely electroluminescence and lasing, as well as photoluminescence and photocurrent data, are recorded with high spatial resolution and consistently interpreted. We find reduced laser emission from the laser segment that is situated closer to the substrate. We show that this is not caused by thermal effects but most likely due to a larger trap concentration within or in the vicinity of the quantum wells of this laser segment. Furthermore, we show that in the unbiased devices the potential gradient in this segment is significantly larger than in the one close to the heat sink. In addition it is shown that the coupling between both waveguides is marginal. The results underline the potential and unique advantages of near-field optical microscopy for nondestructive analysis of optoelectronic device. [ABSTRACT FROM AUTHOR]

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