Muscle activation patterns in paralympic and novices hand cycling during incremental test

The few studies on muscle timing in hand cycling are difficult to classify in the motor skill acquirement due to their variety of methods and content. This study aims to replicate two existing studies and thus to extend and connect the current state of research concerning the muscle timing during synchronous pedalling. The activity on- and offset of biceps brachii, triceps brachii, posterior deltoid, anterior deltoid, upper trapezius, and pectoralis major were identified during an incremental test of an elite and three novice athletes. The results showed differences in inter-muscular coordination between the elite and novice hand cyclists. Although the distinction between active and inactive phases was already evident in novice data, the activation pattern of the elite athlete showed an even more precise differentiation between these two phases. These time windows remained stable even with increasing load accompanied only by changes in all signal amplitude, except for deltoid activity, which showed a later onset and offset with increasing load. Thus, in training of hand cyclist novices, the muscle timing concerning the duration and the crank position should be considered. In future studies, the effect of handicap severity and crank frequency must be studied in greater detail

AC-Elektrolumineszenz und optische Verstärkung in organischen Dünnschicht-Bauelementen

Thema der Arbeit ist ein alternatives Anregungskonzept für organische Leuchtdioden, bei dem elektrische Leistung über isolierte Elektroden zugeführt wird. Dabei können Verlustprozesse vermieden werden, die der Entwicklung einer organischen Laserdiode bisher im Weg stehen. Untersucht werden die Ladungsträgerdynamik und die optischen Eigenschaften der Strukturen. Eine praktische Anwendung des Konzepts stellt die transparente organische Leuchtdiode mit kapazitiver Anregung (KapOLED) dar

Running Performance can be Predicted by Log v-Log t-Models based on Non-Exhaustive Tests and Rating of Perceived Exertion

Individual running performances at different distances can be described by log v-log t-models. The study tests, if rating of perceived exertion while submaximal graded exercise (GXT) and constant load test (CLT) can be used for parameter estimation of log-log-models so that running performance can be predicted. Under laboratory and field conditions 13 and 12 subjects performed a submaximal GXT and CLT, where RPE was measured using RPE15-Scale (Borg, 2004) to calculate 3000m running-performance. Finally, maximal 3000m track runs were done for model verification. Predicted and measured running speed were highly correlated (r = .92 vs. r = .96, p < .001). In the laboratory study predicted speeds were significant lower than measured speeds, whereas by field tests predicted values didn´t differ from measured ones. It is concluded that the presented approach offers an accurate, economic and non-exhaustive possibility of performance prediction in running

Zum Einfluss einer Vorbelastung auf das Anstrengungsempfinden bei einer Ausdauerbelastung

Bei konstanter Belastungsintensität nimmt das Anstrengungsempfinden linear mit der Belastungsdauer zu. Die Studie untersucht den Einfluss einer vorherigen Belastung auf das Anstiegsverhalten bei einer Folgebelastung. Erwartet wird, dass das Anstrengungsempfinden gegenüber einer Belastung im erholten Zustand anfangs erhöht ist und dann gleichermaßen ansteigt. 14 Triathleten/-athletinnen absolvieren zwei Laufbelastungen auf einer 400 m-Laufbahn mit derselben, konstanten Geschwindigkeit über jeweils maximal acht Runden entsprechend einem Anstrengungsempfinden von 15 auf der RPE15-Skala (Borg, 2004) am Anfang des ersten Laufs. Am Ende jeder Runde wird das Anstrengungsempfinden erfasst. Die Pause zwischen den Läufen ist 15 min lang. Das anfängliche Anstrengungsempfinden ist beim zweiten Lauf um 0.7 Einheiten auf der RPE15-Skala erhöht (p < .05), während sich die Steigung der Anstrengungs-Belastungsdauer-Beziehung in beiden Fällen nicht signifikant unterscheidet. Die mittels Regression berechnete maximale Belastungsdauer bis zum Erreichen eines maximalen Anstrengungsempfindens ist beim zweiten Lauf auf 87 % des Ausgangswertes reduziert (p < .05). Geschlussfolgert wird, dass eine Vorbelastung das anfängliche Anstrengungsempfinden erhöht, die maximal mögliche Belastungsdauer reduziert, das Anstiegsverhalten des Anstrengungsempfindens aber nicht beeinflusst

Training im Leistungssport: Modellierung und Simulation von Adaptationsprozessen

Vorgestellt wird ein Modell zur Simulation von Belastungs-, Ermüdungs- und Anpassungsprozessen. Dieses SimBEA-Modell lässt sich anhand von Trainingsdaten zur Belastung und Leistungsfähigkeit individuell kalibrieren, so dass es die personenspezifischen Reaktionsweisen eines Athleten simulieren kann. Zur Prüfung des Modells werden trainingsbegleitende Einzelfalluntersuchungen mit einem Läufer und eine Gruppenuntersuchung mit D-Kader-Triathleten (n = 7) durchgeführt. Die Anpassungs- und Ermüdungsdiagnostik erfolgt mit einem dem Ausdauer-Standard-Test (AST) (Hottenrott, 1993) ähnlichen Verfahren. Für die Modellanpassung des SimBEA-Modells an den so gemessenen Trainingszustand ergeben sich hohe Validitäten. Bei mindestens dreiwöchiger Kalibrierung des Modells zeigt sich eine hohe Validität für einwöchige Leistungsprognosen. Weiter bestätigt wird die Modellstruktur u.a. durch Zusammenhänge zwischen Modellparametern und Wettkampfleistung bzw. anaerober Schwelle. Zwei abschließende Beispiele zeigen Einsatzmöglichkeiten des SimBEA-Modells, die sich auf die Analyse von Trainingsprozessen sowie auf die Simulation von Trainingswirkungen bei der Trainingsplanung beziehen

Giant cell arteritis exclusively detected by 18F-fluorodeoxyglucose positron emission tomography: a case report

INTRODUCTION: This case of giant cell arteritis is noteworthy because it evaded standard diagnostic criteria and only emerged as fever of unknown origin. In this regard, we present (18)F-fluorodeoxyglucose positron emission tomography as a valid diagnostic method. CASE PRESENTATION: This case report describes a 58-year-old Caucasian woman who is a cigarette smoker with a 10-week history of fever of unknown origin, night sweats and weight loss of 12kg. Initially, clinical presentation was suspicious of malignant disease. Laboratory findings detected significantly elevated inflammatory blood parameters including C-reactive protein and elevated erythrocyte sedimentation rate (110mm/hour). Extensive diagnostic workup including microbiological and rheumatological assessment, ultrasonography, endoscopy and computed tomography of abdomen and thorax did not indicate any septic or malignant focus. Eventually, (18)F-fluorodeoxyglucose positron emission tomography was able to reveal arteritis of her aortic arch and supraaortic branches. Subsequently, she commenced steroid and methotrexate therapy that led to sustained remission. CONCLUSIONS: This case of giant cell arteritis may promote discussion regarding a more specific classification for this disease entity. Furthermore, it confirms that (18)F-fluorodeoxyglucose positron emission tomography might serve as a valuable tool for diagnosis of giant cell arteritis, because it could facilitate an accurate and non-invasive detection of lesions of large vessels

A lithium–sulfur full cell with ultralong cycle life: influence of cathode structure and polysulfide additive

Lithium–sulfur batteries are highly attractive energy storage systems, but suffer from structural anode and cathode degradation, capacity fade and fast cell failure (dry out). To address these issues, a carbide-derived carbon (DUT-107) featuring a high surface area (2088 m² g⁻¹), high total pore volume (3.17 cm³ g⁻¹) and hierarchical micro-, meso- and macropore structure is applied as a rigid scaffold for sulfur infiltration. The DUT-107/S cathodes combine excellent mechanical stability and high initial capacities (1098–1208 mA h gs ⁻¹) with high sulfur content (69.7 wt% per total electrode) and loading (2.3–2.9 mgs cm⁻²). Derived from the effect of the electrolyte-to-sulfur ratio on capacity retention and cyclability, conducting salt is substituted by polysulfide additive for reduced polysulfide leakage and capacity stabilization. Moreover, in a full cell model system using a prelithiated hard carbon anode, the performance of DUT-107/S cathodes is demonstrated over 4100 cycles (final capacity of 422 mA h gs ⁻¹), with a very low capacity decay of 0.0118% per cycle. Application of PS additive further boosts the performance (final capacity of 554 mA h gs ⁻¹), although a slightly higher decay of 0.0125% per cycle is observed

Tomographic reconstruction with a generative adversarial network

This paper presents a deep learning algorithm for tomographic reconstruction (GANrec). The algorithm uses a generative adversarial network (GAN) to solve the inverse of the Radon transform directly. It works for independent sinograms without additional training steps. The GAN has been developed to fit the input sinogram with the model sinogram generated from the predicted reconstruction. Good quality reconstructions can be obtained during the minimization of the fitting errors. The reconstruction is a self-training procedure based on the physics model, instead of on training data. The algorithm showed significant improvements in the reconstruction accuracy, especially for missing-wedge tomography acquired at less than 180° rotational range. It was also validated by reconstructing a missing-wedge X-ray ptychographic tomography (PXCT) data set of a macroporous zeolite particle, for which only 51 projections over 70° could be collected. The GANrec recovered the 3D pore structure with reasonable quality for further analysis. This reconstruction concept can work universally for most of the ill-posed inverse problems if the forward model is well defined, such as phase retrieval of in-line phase-contrast imaging

Solar cells on multicrystalline silicon thin films converted from low‐cost soda‐lime glass

Fabrication and characterization of solar cells based on multicrystalline silicon (mc-Si) thin films are described and synthesized from low-cost soda-lime glass (SLG). The aluminothermic redox reaction of the silicon oxide in SLG during low-temperature annealing at 600 – 650 °C leads to an mc-Si thin film with large grains of lateral dimensions in the millimeter range, and moderate p-type conductivity with an average Al acceptor concentration between 5 × 1016 and 1.2 × 1017 cm−3 in the bulk. A residual composite layer of mainly alumina and unreacted Al forms beneath the mc-Si thin film as the second product of the crystalline silicon synthesis (CSS) process, which can be used as rear contact in a vertical solar cell design. The mc-Si absorber (≈10 µm) is thin enough that the diffusion length given by a minority carrier lifetime of ≈1 µs exceeds the path length to the top contact several times. Homojunction and heterojunction diodes have been fabricated on the mc-Si thin films and show great potential of CSS for the realization of high-performance solar cells

PtyNAMi: ptychographic nano-analytical microscope

Ptychographic X-ray imaging at the highest spatial resolution requires an optimal experimental environment, providing a high coherent flux, excellent mechanical stability and a low background in the measured data. This requires, for example, a stable performance of all optical components along the entire beam path, high temperature stability, a robust sample and optics tracking system, and a scatter-free environment. This contribution summarizes the efforts along these lines to transform the nanoprobe station on beamline P06 (PETRA III) into the ptychographic nano-analytical microscope (PtyNAMi