Kinematically Complete Experiment on Transfer Excitation in Intermediate-Energy p + He Collisions

We have performed a kinematically complete experiment on transfer excitation in intermediate-energy proton-helium collisions. The differential cross sections were compared to double excitation data and a nonperturbative time-dependent calculation. This comparison reveals the importance of dynamic couplings between the motion of the heavy nuclei and electronic transitions and/or electron-electron correlation effects

Projectile Angular-Differential Cross Sections for Transfer and Transfer Excitation in Proton Collisions with Helium

Projectile angular-differential cross sections for single-transfer and transfer excitation have been calculated with the two-center extension of the nonperturbative basis generator method for 5-200 keV proton-helium collisions. The calculations are based on the independent electron model, and the eikonal approximation has been used to extract angular-differential cross sections from impact-parameter-dependent transition amplitudes. The present results are compared with experimental and previous theoretical data where available. In particular, we consider the ratio of transfer excitation to single capture versus double excitation to single excitation at intermediate energies. An experimentally observed structure in this ratio at a scattering angle about 0.5 mrad is qualitatively reproduced, while a previous classical evaluation failed in this respect. Therefore, we conclude that this structure is caused by quantum mechanical heavy-particle-electron couplings

Molecular and functional profiling identifies therapeutically targetable vulnerabilities in plasmablastic lymphoma

B-cell lymphoma; Cancer geneticsLinfoma de células B; Genética del cáncerLimfoma de cèl·lules B; Genètica del càncerPlasmablastic lymphoma (PBL) represents a rare and aggressive lymphoma subtype frequently associated with immunosuppression. Clinically, patients with PBL are characterized by poor outcome. The current understanding of the molecular pathogenesis is limited. A hallmark of PBL represents its plasmacytic differentiation with loss of B-cell markers and, in 60% of cases, its association with Epstein-Barr virus (EBV). Roughly 50% of PBLs harbor a MYC translocation. Here, we provide a comprehensive integrated genomic analysis using whole exome sequencing (WES) and genome-wide copy number determination in a large cohort of 96 primary PBL samples. We identify alterations activating the RAS-RAF, JAK-STAT, and NOTCH pathways as well as frequent high-level amplifications in MCL1 and IRF4. The functional impact of these alterations is assessed using an unbiased shRNA screen in a PBL model. These analyses identify the IRF4 and JAK-STAT pathways as promising molecular targets to improve outcome of PBL patients.Open Access funding enabled and organized by Projekt DEAL

Molecular and functional profiling identifies therapeutically targetable vulnerabilities in plasmablastic lymphoma

Plasmablastic lymphoma (PBL) represents a rare and aggressive lymphoma subtype frequently associated with immunosuppression. Clinically, patients with PBL are characterized by poor outcome. The current understanding of the molecular pathogenesis is limited. A hallmark of PBL represents its plasmacytic differentiation with loss of B-cell markers and, in 60% of cases, its association with Epstein-Barr virus (EBV). Roughly 50% of PBLs harbor a MYC translocation. Here, we provide a comprehensive integrated genomic analysis using whole exome sequencing (WES) and genome-wide copy number determination in a large cohort of 96 primary PBL samples. We identify alterations activating the RAS-RAF, JAK-STAT, and NOTCH pathways as well as frequent high-level amplifications in MCL1 and IRF4. The functional impact of these alterations is assessed using an unbiased shRNA screen in a PBL model. These analyses identify the IRF4 and JAK-STAT pathways as promising molecular targets to improve outcome of PBL patients

Inner- and outer-shell electron dynamics in proton collisions with sodium atoms

p+Na collisions have been investigated theoretically and experimentally at impact energies in the keV regime. We present results for capture and ionization processes; and, in particular, analyse the role of initial inner-shell electrons, whose active participation is identified in the experiments through the analysis of recoil-ion momentum spectra. Quantum-mechanical calculations within the independent particle model have been carried out for all active electrons. A very good overall agreement between the theoretical and experimental results is found. The calculations support the observation that capture from inner shells is an important reaction channel even at relatively low impact energies, and dominates total capture above 40 keV

Host element chemical diffusion studies in high-purity Fe-Cr-Al model alloys

In the temperature range 800°C ≤ T ≤ 1100°C, interdiffusion experiments using diffusion couples were carried out in vacuum on model alloys Fex-Cry-Alz with 0.57 ≤ x ≤ 0.80, 0.06 ≤ y ≤ 0.32, 0.01 ≤ z ≤ 0.24. Disk shape diffusion couples with different concentrations of host elements were pressed together in a cylindrical container. After annealing, the joined couples were sectioned parallel to the diffusion direction, polished and cleaned for the electron probe microanalyses (EPMA). From the resulting concentration profiles the two main and two cross-interdiffusion coefficients required for the description of ternary diffusion were determined. For the calculation of the ternary diffusivities, a recent numerical approach was used in which the four ternary interdiffusion coefficients are determined over a selected composition range from a single diffusion couple experiment. For the main coefficients [math] and [math], activation enthalpies were calculated in the high and low Cr and Al content areas, respectively

Single-electron capture in keV Ar15+...18++He collisions

Single-electron capture in 14 keV q(-1) Ar15+...18++He collisions is investigated both experimentally and theoretically. Partial cross sections and projectile scattering angle dependencies have been deduced from the target ion recoil momenta measured by the COLTRIMS technique. The comparison with close-coupling results obtained from a two-centre extension of the basis generator method yields good overall agreement, demonstrating the applicability of close-coupling calculations to collision systems involving highly charged ions in charge states up to 18+.FANTOM German Academic Exchange Servic

Single-electron capture in keV Ar15+...18++He collisions

Single-electron capture in 14 keV q−1 Ar15+...18++He collisions is investigated both experimentally and theoretically. Partial cross sections and projectile scattering angle dependencies have been deduced from the target ion recoil momenta measured by the COLTRIMS technique. The comparison with close-coupling results obtained from a two-centre extension of the basis generator method yields good overall agreement, demonstrating the applicability of close-coupling calculations to collision systems involving highly charged ions in charge states up to 18+