Description: New marine geophysical data acquired across the partly ice‐covered northern East Greenland continental margin highlight a complex interaction between tectonic and magmatic events. Breakup‐related lava flows are imaged in reflection seismic data as seaward dipping reflectors (SDRs), which are found to decrease in size both northwards and southwards from a central point at 75° N. We provide evidence that the magnetic anomaly pattern in the shelf area is related to volcanic phases and not to the presence of oceanic crust. The remnant magnetization of the individual lava flows is used to deduce a relative timing of the emplacement of the volcanic wedges. We find that the SDRs have been emplaced over a period of 2‐4 Ma progressively from north to south and from landward to seaward. The new data indicate a major post‐middle Eocene magmatic phase around the landward termination of the West Jan Mayen Fracture Zone. This post‐40 Ma volcanism likely was associated with the progressive separation of the Jan Mayen microcontinent from East Greenland. The break‐up of the Greenland Sea started at several isolated seafloor spreading cells whose location was controlled by rift structures and led to the present‐day segmentation of the margin. The original rift basins were subsequently connected by steady‐state seafloor spreading that propagated southwards, from the Greenland Fracture Zone to the Jan Mayen Fracture Zone. Key Points Polyphase Cenozoic volcanic rifting and consecutive emplacement of breakup‐related lava flows units along the northern East Greenland margin Breakup along restricted margin segments is followed by north to south directed progressive opening of the Greenland Sea Widespread post‐middle Eocene (〈 40 Ma) offshore magmatism, associated with the breakup of the Jan Mayen microcontinent from East Greenland

Description: Background— Heart development is tightly regulated by signaling events acting on a defined number of progenitor and differentiated cardiac cells. Although loss of function of these signaling pathways leads to congenital malformation, the consequences of cardiac progenitor cell or embryonic cardiomyocyte loss are less clear. In this study, we tested the hypothesis that embryonic mouse hearts exhibit a robust mechanism for regeneration after extensive cell loss. Methods and Results— By combining a conditional cell ablation approach with a novel blastocyst complementation strategy, we generated murine embryos that exhibit a full spectrum of cardiac progenitor cell or cardiomyocyte ablation. Remarkably, ablation of up to 60% of cardiac progenitor cells at embryonic day 7.5 was well tolerated and permitted embryo survival. Ablation of embryonic cardiomyocytes to a similar degree (50% to 60%) at embryonic day 9.0 could be fully rescued by residual myocytes with no obvious adult cardiac functional deficit. In both ablation models, an increase in cardiomyocyte proliferation rate was detected and accounted for at least some of the rapid recovery of myocardial cellularity and heart size. Conclusion— Our study defines the threshold for cell loss in the embryonic mammalian heart and reveals a robust cardiomyocyte compensatory response that sustains normal fetal development.

Description: Aims Fibrosis increases arrhythmogenicity in myocardial tissue by causing structural and functional disruptions in the cardiac syncytium. Forced fusion of fibroblastic cells with adjacent cardiomyocytes may theoretically resolve these disruptions. Therefore, the electrophysiological effects of such electrical and structural integration of fibroblastic cells into a cardiac syncytium were studied. Methods and results Human ventricular scar cells (hVSCs) were transduced with lentiviral vectors encoding enhanced green fluorescent protein alone (eGFP-hVSCs) or together with the fusogenic vesicular stomatitis virus G protein (VSV-G/eGFP-hVSCs) and subsequently co-cultured (1:4 ratio) with neonatal rat ventricular cardiomyocytes (NRVMs) in confluent monolayers yielding eGFP- and VSV-G/eGFP-co-cultures, respectively. Cellular fusion was induced by brief exposure to pH = 6.0 medium. Optical mapping experiments showed eGFP-co-cultures to be highly arrhythmogenic [43.3% early afterdepolarization (EAD) incidence vs. 7.7% in control NRVM cultures, P 〈 0.0001], with heterogeneous prolongation of action potential (AP) duration (APD). Fused VSV-G/eGFP-co-cultures displayed markedly lower EAD incidence (4.6%, P 〈 0.001) than unfused co-cultures, associated with decreases in APD, APD dispersion, and decay time of cytosolic Ca 2+ waves. Heterokaryons strongly expressed connexin43 (Cx43). Also, maximum diastolic potential in co-cultures was more negative after fusion, while heterokaryons exhibited diverse mixed NRVM/hVSC whole-cell current profiles, but consistently showed increased outward K v currents compared with NRVMs or hVSCs. Inhibition of K v channels by tetraethylammonium chloride abrogated the anti-arrhythmic effects of fusion in VSV-G/eGFP-co-cultures raising EAD incidence from 7.9 to 34.2% ( P 〈 0.001). Conclusion Forced fusion of cultured hVSCs with NRVMs yields electrically functional heterokaryons and reduces arrhythmogenicity by preventing EADs, which is, at least partly, attributable to increased repolarization force.

Description: Author(s): R. Engels, M. Gaißer, R. Gorski, K. Grigoryev, M. Mikirtychyants, A. Nass, F. Rathmann, H. Seyfarth, H. Ströher, P. Weiss, L. Kochenda, P. Kravtsov, V. Trofimov, N. Tschernov, A. Vasilyev, M. Vznuzdaev, and H. Paetz gen. Schieck The preservation of the nuclear polarization of hydrogen atoms during the recombination to molecules was observed on different surface materials in the temperature range from 45 to 100 K and for magnetic fields up to 1 T. On a gold and a fused quartz surface, the expected molecular polarization of a… [Phys. Rev. Lett. 115, 113007] Published Thu Sep 10, 2015

Description: Halotectonic pulses in the Bays of Mecklenburg and Kiel including the Glückstadt Graben have been previously explained by reactive and passive diapirism or differential load, e.g., caused by sub-salt faulting. Salt walls that formed above those sub-salt faults further grew during phases of inversion. Consequently, phases of enhanced halotectonics have been mainly related to the Triassic W-E extension, Jurassic North Sea doming, the Alpine orogeny. The location of salt walls was attributed to deep rooted sub-salt faults. Alternative concepts of salt tectonics have been developed for continental slopes. Salt deformation may start already during the precipitation of the salt due to basin floor tilt, which may result from thermo-tectonic subsidence or from the salt load. As the consequence the emerging salt layer creeps towards the basin center causing internal folding and thrusting (“gravity gliding”). The resulting thickness variations of the salt are considered to be significant enough that sedimentation in the depressions directly initiate differential load and passive diapirism. Extensional faulting in the basin margin and diapirism in the central basin continues if basin subsidence continues or if basin margin sedimentation causes differential load on the salt rim (“gravity spreading”). In the course of RV MARIA S. MERIAN expedition MSM52 (BalTec) in March 2016 we imaged the tectonic conditions within the Paleozoic to recent sedimentary strata of the southern Baltic Sea between the North German Basin across the Tornquist Fan with yet unparalleled vertical resolution. The equipment consisted of 8 GI-Guns (70 Hz dominant frequency) as a source array and a digital seismic streamer of 2700 m active length. Due to the short initial offset of 37 meters between the seismic source array and the first active streamer section the data image without gap the subsurface geology from the Paleozoic strata or basement up to the seafloor. A SW-NE striking seismic profiles from the central Mecklenburg Bay to the Skurup Block covers the northeastern North German Basin and its marginal setting where several fault systems are present. The Agricola fault system is a set of arcuate faults in the Post-Permian strata which emerged above along the pinch-out line of the mobile salt. Faults reach partly up to the seafloor suggesting recent displacement. Fault planes dip mainly towards the basin. These faults can well be understood as the consequence of salt gliding towards the basin center, hence, as the consequence of gravity gliding. The Werre and Prerow fault systems evolved above a salt anticline on top of the Grimmen High. A first major halotectonic pulse is suggested for the upper Triassic which led to salt depletion and enhanced deposition. During the Cretaceous inversion of the Grimmen High, a salt pillow emerged between both fault systems when the salt moved towards northeast and southwest. The absence of significant fault displacements beneath the salt pillows in the Mecklenburg bay is further consistent with the gravity gliding concept which explains salt pillow growth by thin-skinned shortening.