Polaronic Contributions to Friction in a Manganite Thin Film

Despite the huge importance of friction in regulating movement in all natural and technological processes, the mechanisms underlying dissipation at a sliding contact are still a matter of debate. Attempts to explain the dependence of measured frictional losses at nanoscale contacts on the electronic degrees of freedom of the surrounding materials have so far been controversial. Here, it is proposed that friction can be explained by considering damping of stick-slip pulses in a sliding contact. Based on friction force microscopy studies of La$_{(1-x)}$Sr$_x$MnO$_3$ films at the ferromagnetic-metallic to paramagnetic-polaronic conductor phase transition, it is confirmed that the sliding contact generates thermally-activated slip pulses in the nanoscale contact, and argued that these are damped by direct coupling into phonon bath. Electron-phonon coupling leads to the formation of Jahn-Teller polarons and a clear increase in friction in the high temperature phase. There is no evidence for direct electronic drag on the atomic force microscope tip nor any indication of contributions from electrostatic forces. This intuitive scenario, that friction is governed by the damping of surface vibrational excitations, provides a basis for reconciling controversies in literature studies as well as suggesting possible tactics for controlling friction

Medicine in Spine Exercise [MiSpEx]

$\textbf {Idiopathic as well as nonspecific low back pain}$ is relevant in health care systems as well asinleisure and high-performance sports. Neuromuscular and/or structural deficits, mostly accompanied by biopsychological factors,are known risk factors for both the onset and chronification of symptoms. Meta-analytic evidence describes positive effects of physical activity. However, type, dose-response relation, minimum of training required and setting-specific implementation has not been fullyclarified. $\textbf {Since 2011, the national research network}$ „Medicine in Spine Exercise“ [MiSpEx] has beenfollowing a project layout called „Ran Rücken“ focussing on the development and validation of intervention programs including neuromuscular and pain adaptation moderated by individual training status, pain behaviour, allostatic load and social settings. Overall about 8000 patients and athletes have been and are being followed experimentally and clinically in 34 studies. $\textbf {It could be shown}$ that a training program focussing on compensation of external loads elicited by perturbations is effective in prevention and rehabilitation in both athletes and general population. Besides validation of further consecutively developed programs emphasis is put on the evaluation of transfer strategies to medical systems, sports as well as general population. Finally, the evaluation of an efficient dose-response relation is addressed.$\textbf {Idiopathische und unspezifische Rückenschmerzen}$ sind relevant für das Gesundheitssystem sowie für Alltag, Breiten- und Spitzensport. Neuromuskuläre und strukturelle Defizite, häufig begleitet von biopsychosozialen Faktoren, sind ursächlich für den Beginn und die Chronifizierung der Symptome. Evident in Therapie und Prävention ist körperliche Aktivität, wobei nicht abschließend geklärt ist, welche Art und Dosierung effektiv ist, welches Trainingsminimum erreicht werden muss und wie unterschiedliche Adressatenkreise für einen nachhaltigen Effekt angesprochen werden müssen. $\textbf {Das nationale Forschungsnetzwerk}$ „Medicine in Spine Exercise“ [MiSpEx] arbeitet unter dem Projektnamen „Ran Rücken“ seit 2011 an der Entwicklung und Validierung adressatengerechter Interventionsprogramme mit dem Ziel der Adaptation neuromuskulärer Interaktionen und Schmerz, moderiert durch Trainingszustand, Schmerzempfinden, allostatische Last und Versorgungskontext. Insgesamt wurden und werden rund 8000 Gesunde und Patienten mit Rückenschmerzen aus der Allgemeinbevölkerung und dem Spitzensport in 34 Projekten wissenschaftlich und klinisch betreut. $\textbf {Es konnte nachgewiesen werden}$, dass ein Training zur Kompensation externer Störreize (Perturbationen) bei geringem Aufwand präventiv und therapeutisch wirksam ist. Neben der Validierung neuer, konsekutiv auf den Ergebnissen aufgebauter Interventionsmodule, stehen die Evaluation von Transferstrategien in die medizinische Versorgung, die Systeme des Leistungssports und die Gesamtgesellschaft sowie die Analyse von Dosis-Wirkungsbeziehungen im Fokus des Projekte

Growth of Murine Splenic Tissue Is Suppressed by Lymphotoxin β-Receptor Signaling (LTβR) Originating from Splenic and Non-Splenic Tissues.

Development and maintenance of secondary lymphoid organs such as lymph nodes and spleen essentially depend on lymphotoxin β-receptor (LTβR) signaling. It is unclear, however, by which molecular mechanism their size is limited. Here, we investigate whether the LTβR pathway is also growth suppressing. By using splenic tissue transplantation it is possible to analyze a potential contribution of LTβR signaling inside and outside of the implanted tissue. We show that LTβR signaling within the endogenous spleen and within non-splenic tissues both significantly suppressed the regeneration of implanted splenic tissue. The suppressive activity positively correlated with the total number of LTβR expressing cells in the animal (regenerate weights of 115 ± 8 mg in LTβR deficient recipients and of 12 ± 9 mg in wild-type recipients), affected also developed splenic tissue, and was induced but not executed via LTβR signaling. Two-dimensional differential gel electrophoresis and subsequent mass spectrometry of stromal splenic tissue was applied to screen for potential factors mediating the LTβR dependent suppressive activity. Thus, LTβR dependent growth suppression is involved in regulating the size of secondary lymphoid organs, and might be therapeutically used to eradicate tertiary lymphoid tissues during autoimmune diseases

Recurrent somatic alterations of FGFR1 and NTRK2 in pilocytic astrocytoma

Pilocytic astrocytoma, the most common childhood brain tumor(1), is typically associated with mitogen-activated protein kinase (MAPK) pathway alterations(2). Surgically inaccessible midline tumors are therapeutically challenging, showing sustained tendency for progression(3) and often becoming a chronic disease with substantial morbidities(4). Here we describe whole-genome sequencing of 96 pilocytic astrocytomas, with matched RNA sequencing (n=73), conducted by the International Cancer Genome Consortium (ICGC) PedBrain Tumor Project. We identified recurrent activating mutations in FGFR1 and PTPN11 and novel NTRK2 fusion genes in non-cerebellar tumors. New BRAF activating changes were also observed. MAPK pathway alterations affected 100% of tumors analyzed, with no other significant mutations, indicating pilocytic astrocytoma as predominantly a single-pathway disease. Notably, we identified the same FGFR1 mutations in a subset of H3F3A-mutated pediatric glioblastoma with additional alterations in NF1(5). Our findings thus identify new potential therapeutic targets in distinct subsets of pilocytic astrocytoma and childhood glioblastoma

A global test of brief reappraisal interventions on emotions during the COVID-19 pandemic

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion regulation strategy which modifies how one thinks about a situation. Participants from 87 countries/regions (N = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vs. both control conditions) had consistent effects in reducing negative emotions and increasing positive emotions across different measures. Reconstrual and repurposing had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world to build resilience during the pandemic and beyond