The Valence Band Structure of Gadolinium Studied with Time-Resolved Photoemission

We have studied the response of the exchange split valence bands of ferromagnetic gadolinium tofemtosecond laser excitation. We observe a drop of the exchange splitting with a time constant of 0.9 ps but different response times of minority and majority spin bands. Furthermore, even above the Curie temperature there is a finite exchange splitting, which also decreases with laser excitation

Crustal structure of the Azores Archipelago from Rayleigh wave ellipticity data

Determining the crustal structure of ocean island volcanoes is important to understand the formation and tectonic evolution of the oceanic lithosphere and tectonic swells in marine settings, and to assess seismic hazard in the islands. The Azores Archipelago is located near a triple junction system and is possibly under the influence of a mantle plume, being at the locus of a wide range of geodynamic processes. However, its crustal structure is still poorly constrained and debated due to the limited seismic coverage of the region and the peculiar linear geometry of the islands. To address these limitations, in this study we invert teleseismic Rayleigh wave ellipticity measurements for 1-D shear wave speed (VS) crustal models of the Azores Archipelago. Moreover, we test the reliability of these new models by using them in independent moment tensor inversions of local seismic data and demonstrate that our models improve the waveform fit compared to previous models. We find that data from the westernmost seismic stations used in this study require a shallower Moho depth (∼10 km) than data from stations in the eastern part of the archipelago (∼13–16 km). This apparent increase in the Moho depth with increasing distance from the mid-Atlantic ridge (MAR) is expected. However, the rate at which Moho deepens away from the MAR is greater than that predicted from a half-space cooling model, suggesting that local tectonic perturbations have modified crustal structure. The 1-D VS models obtained beneath the westernmost seismic stations also show higher wave speeds than for the easternmost stations, which correlates well with the ages of the islands except Santa Maria Island. We interpret the relatively low VS profile found beneath Santa Maria Island as resulting from underplating, which agrees with previous geological studies of the island. Compared to a recent receiver function study of the region, the shallow structure (top ∼2 km) in our models shows lower shear wave speed, which may have important implications for future hazard studies of the region. More generally, the new seismic crustal models we present in this study will be useful to better understand the tectonics, seismicity, moment tensors and strong ground motions in the region

Ultrafast Spin Density Wave Transition in Chromium Governed by Thermalized Electron Gas

The energy and momentum selectivity of time- and angle-resolved photoemission spectroscopy is exploited to address the ultrafast dynamics of the antiferromagnetic spin density wave (SDW) transition photoexcited in epitaxial thin films of chromium. We are able to quantitatively extract the evolution of the SDW order parameter Δ through the ultrafast phase transition and show that Δ is governed by the transient temperature of the thermalized electron gas, in a mean field description. The complete destruction of SDW order on a sub-100 fs time scale is observed, much faster than for conventional charge density wave materials. Our results reveal that equilibrium concepts for phase transitions such as the order parameter may be utilized even in the strongly nonadiabatic regime of ultrafast photoexcitation

Phosphorylation-dependent differences in CXCR4-LASP1-AKT1 Interaction between breast cancer and chronic myeloid leukemia

The serine/threonine protein kinase AKT1 is a downstream target of the chemokine receptor4 (CXCR4), and both proteins play a central role in the modulation of diverse cellular processes,including proliferation and cell survival. While in chronic myeloid leukemia (CML) the CXCR4is downregulated, thereby promoting the mobilization of progenitor cells into blood, the receptoris highly expressed in breast cancer cells, favoring the migratory capacity of these cells. Recently,the LIM and SH3 domain protein 1 (LASP1) has been described as a novel CXCR4 binding partnerand as a promoter of the PI3K/AKT pathway. In this study, we uncovered a direct binding ofLASP1, phosphorylated at S146, to both CXCR4 and AKT1, as shown by immunoprecipitation assays,pull-down experiments, and immunohistochemistry data. In contrast, phosphorylation of LASP1at Y171 abrogated these interactions, suggesting that both LASP1 phospho-forms interact. Finally,findings demonstrating different phosphorylation patterns of LASP1 in breast cancer and chronicmyeloid leukemia may have implications for CXCR4 function and tyrosine kinase inhibitor treatment

In Vivo Emergence of UL56 C325Y Cytomegalovirus Resistance to Letermovir in a Patient with Acute Myeloid Leukemia after Hematopoietic Cell Transplantation

CMV associated tissue-invasive disease is associated with a considerable risk of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Recently, the terminase inhibitor letermovir (LMV) has been approved for prophylaxis of CMV infection in HSCT. We hereby report a 60-year-old female experiencing CMV reactivation after HSCT in a CMV seronegative donor-constellation. Due to ongoing elevated CMV viral load and drug-associated myelosuppression, which prevented ganciclovir therapy, treatment was replaced by foscarnet. Due to nephrotoxicity, foscarnet was switched to LMV. The patient developed skin GvHD and prednisolone was started. Subsequently, CMV viremia worsened despite LMV therapy. Genotyping revealed the mutation C325Y of the CMV UL56 terminase being associated with high-level resistance against LMV. Prolonged uncontrolled low-level viremia due to prednisolone treatment may have favored the selection of drug-resistant CMV. Despite the excellent toxicity profile of LMV, physicians should be aware of risk factors for the emergence of resistance