Spin dynamics in semiconductors

This article reviews the current status of spin dynamics in semiconductors which has achieved a lot of progress in the past years due to the fast growing field of semiconductor spintronics. The primary focus is the theoretical and experimental developments of spin relaxation and dephasing in both spin precession in time domain and spin diffusion and transport in spacial domain. A fully microscopic many-body investigation on spin dynamics based on the kinetic spin Bloch equation approach is reviewed comprehensively.Comment: a review article with 193 pages and 1103 references. To be published in Physics Reports

Elucidating the mechanism of ferrocytochrome c heme disruption by peroxidized cardiolipin

The interaction of peroxidized cardiolipin with ferrocytochrome c induces two kinetically and chemically distinct processes. The first is a rapid oxidation of ferrocytochrome c, followed by a slower, irreversible disruption of heme c. The oxidation of ferrocytochrome c by peroxidized cardiolipin is explained by a Fenton-type reaction. Heme scission is a consequence of the radical-mediated reactions initiated by the interaction of ferric heme iron with peroxidized cardiolipin. Simultaneously with the heme c disruption, generation of hydroxyl radical is detected by EPR spectroscopy using the spin trapping technique. The resulting apocytochrome c sediments as a heterogeneous mixture of high aggregates, as judged by sedimentation analysis. Both the oxidative process and the destructive process were suppressed by nonionic detergents and/or high ionic strength. The mechanism for generating radicals and heme rupture is presented

Semiconductor Spintronics

Spintronics refers commonly to phenomena in which the spin of electrons in a solid state environment plays the determining role. In a more narrow sense spintronics is an emerging research field of electronics: spintronics devices are based on a spin control of electronics, or on an electrical and optical control of spin or magnetism. This review presents selected themes of semiconductor spintronics, introducing important concepts in spin transport, spin injection, Silsbee-Johnson spin-charge coupling, and spindependent tunneling, as well as spin relaxation and spin dynamics. The most fundamental spin-dependent nteraction in nonmagnetic semiconductors is spin-orbit coupling. Depending on the crystal symmetries of the material, as well as on the structural properties of semiconductor based heterostructures, the spin-orbit coupling takes on different functional forms, giving a nice playground of effective spin-orbit Hamiltonians. The effective Hamiltonians for the most relevant classes of materials and heterostructures are derived here from realistic electronic band structure descriptions. Most semiconductor device systems are still theoretical concepts, waiting for experimental demonstrations. A review of selected proposed, and a few demonstrated devices is presented, with detailed description of two important classes: magnetic resonant tunnel structures and bipolar magnetic diodes and transistors. In most cases the presentation is of tutorial style, introducing the essential theoretical formalism at an accessible level, with case-study-like illustrations of actual experimental results, as well as with brief reviews of relevant recent achievements in the field.Comment: tutorial review; 342 pages, 132 figure

German Business Panel: Empirische Evidenz zu den Auswirkungen der Corona-Krise auf deutsche Unternehmen

Das German Business Panel liefert zeitnahe Indikatoren, welche Auswirkungen der Verlauf der Corona-Krise auf deutsche Unternehmen hat und wie diese auf die wirtschaftlichen Herausforderungen reagieren. Die Daten belegen, dass das Jahr 2020 für die Unternehmen erhebliche Belastungen von Umsatz und Gewinn gebracht hat. Die Verschärfung des Lockdowns im Dezember hat zwar insgesamt nur geringe zusätzliche Effekte gezeigt, dabei allerdings Gewinne innerhalb von Branchen umverteilt. In der zweiten Jahreshälfte ist die Zufriedenheit mit der Ausgestaltung der Staatshilfen leicht angestiegen. Durch deren verbesserte Ausgestaltung konnte zwar ein weiterer Gewinnrückgang aufgehalten werden. Der Ausblick auf die gesamtwirtschaftliche Entwicklung und Unternehmensausfälle im Jahr 2021 hat sich allerdings gleichzeitig deutlich verschlechtert

Stereotactic body radiotherapy (SBRT) for pulmonary metastases from renal cell carcinoma-a multicenter analysis of the German working group "Stereotactic Radiotherapy"

Background Renal cell carcinoma (RCC) is traditionally considered to be radioresistant. Radiotherapy response rates are believed to improve with hypofractionated, high dose stereotactic body radiotherapy (SBRT). However, limited data exist regarding the role of SBRT in the treatment of pulmonary metastases. Methods The working group "Stereotactic Radiotherapy" of the German Society of Radiation Oncology analyzed its multi-institutional database of more than 700 patients who received SBRT for pulmonary metastases. Treatment was performed at 10 centers between 2001 and 2016. Patients with metastatic RCC were included in the study. Tumor characteristics, treatment details, and follow-up data including survival, local control (LC), distant metastases, and toxicity were evaluated. Results A total of 46 RCC patients treated with SBRT for 67 lung metastases were identified, who received a median total biologically effective dose (BEDiso) at planning target volume (PTV) isocenter of 117.0 Gy (range, 48.0-189.0 Gy). A median fractional dose of 20.8 Gy at isocenter (range, 6.0-37.9 Gy) was administered in a median number of 3 fractions (1-8 fractions). After a median follow-up time of 28.3 months for all patients, 1- and 3-year LC rates were 98.1% and 91.9%, with corresponding 1- and 3-year overall survival (OS) of 84.3% and 43.8%, respectively. Pulmonary metastases treated with BEDiso ≥130 Gy showed a trend for superior LC (P=0.054). OS was significantly improved in both uni- and multivariate analysis for patients with higher Karnofsky performance scale, lower maximum pulmonary metastasis diameter and lack of post-SBRT systemic therapy due to progression (P=0.014; P=0.049; P=0.006). Only mild acute and late toxicity was reported. Conclusions SBRT for pulmonary metastases from RCC was associated with low treatment-associated toxicity, promising survival, and excellent LC, especially in those patients receiving a BEDiso ≥130 Gy

Stereotactic body radiotherapy (SBRT) for medically inoperable lung metastases-A pooled analysis of the German working group "stereotactic radiotherapy"

OBJECTIVES The current literature on stereotactic body radiotherapy (SBRT) for oligometastatic disease is characterized by small patient cohorts with heterogeneous primary tumors, metastases location and dose regimes. Hence, this study established a multi-institutional database of 700 patients treated with SBRT for pulmonary metastases to identify prognostic factors influencing survival and local control. MATERIALS AND METHODS All German radiotherapy departments were contacted and invited to participate in this analysis. A total number of 700 patients with medically inoperable lung metastases treated with SBRT in 20 centers between 1997 and 2014 were included in a database. Primary and metastatic tumor characteristics, treatment characteristics and follow-up data including survival, local control, distant metastases, and toxicity were evaluated. Lung metastases were treated with median PTV-encompassing single doses of 12.5Gy (range 3.0-33.0Gy) in a median number of 3 fractions (range 1-13). RESULTS After a median follow-up time of 14.3 months, 2-year local control (LC) and overall survival (OS) were 81.2% and 54.4%, respectively. In multivariate analysis, OS was most significantly influenced by pretreatment performance status, maximum metastasis diameter, primary tumor histology, time interval between primary tumor diagnosis and SBRT treatment and number of metastases. For LC, independent prognostic factors were pretreatment performance status, biological effective dose (BED) at PTV isocenter (BEDISO) and single fraction (PTV-encompassing) dose in multivariate analysis. Radiation-induced pneumonitis grade 2 or higher was observed in 6.5% of patients. The only factor significantly influencing toxicity was BEDISO (p=0.006). CONCLUSION SBRT for medically inoperable patients with pulmonary metastases achieved excellent local control and promising overall survival. Important prognostic factors were identified for selecting patients who might benefit most from this therapy approach