Time-dependent independent-particle model calculation of multiple capture and ionization processes in p-Ar, (p)over-bar- Ar, and He2+-Ar collisions

Previous work on multielectron transitions in proton, antiproton, and He2+-ion impact on neon is extended to the case of argon targets for collision energies in the 5-1000 keV/amu range. Global quantities such as net electron loss from the target, net capture, and net ionization are predicted within experimental errors using a spherically symmetric optimized effective target atom potential with dynamical screening effects based on the time-dependent net ionization probability. The inclusion of target response is crucial in order to obtain correct positions and heights for the peaks in the net ionization cross sections. Effects due to cascading following multiple outer-shell excitation are found to be appreciable at energies between 10 and 100 keV/amu, but are overestimated by the statistical model. L-shell vacancy production is reported to affect recoil charge state production at energies above 200 keV/amu for charge states qgreater than or equal to3. At low and intermediate energies, the independent-particle model is shown to overestimate q-fold recoil ion production significantly for qgreater than or equal to3 for proton impact signaling the role of electronic correlations for these channels. For antiproton impact the q=3 cross section is consistent with the independent-particle model

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

State selective single-electron capture in O6++Nacollisions

Single-electron capture in O6+ + Na collisions at 1-9 keV/amu collision energy has been studied both experimentally and theoretically. Partial cross sections for electron capture into n = 5, 6, 7, 8 and n >= 9 have been obtained from target recoil momenta measured by the technique of MOTRIMS and are compared with close-coupling results obtained from a two-centre extension of the basis generator method. An overall good agreement is found, concerning the relative magnitude as well as the energy dependence. Also the contribution of ionization could be extracted from the recoil spectra. The ionization cross section is very small but strongly increases with energy

Revealing the Non-s 2 Contributions in the Momentum Wave Function of Ground-state He

The correlated Tunneling Transfer Ionization (TuTI) channel in fast 4-body processes p + He → H0 + He2+ +e is utilized to probe the highly correlated asymptotic parts of the He ground-state momentum space wave function. In this reaction, predominantly

Assessing the impact of COVID-19 on liver cancer management (CERO-19)

Background & Aims: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems and it may have heavily impacted patients with liver cancer (LC). Herein, we evaluated whether the schedule of LC screening or procedures has been interrupted or delayed because of the COVID-19 pandemic. Methods: An international survey evaluated the impact of the COVID-19 pandemic on clinical practice and clinical trials from March 2020 to June 2020, as the first phase of a multicentre, international, and observational project. The focus was on patients with hepatocellular carcinoma or intrahepatic cholangiocarcinoma, cared for around the world during the first COVID-19 pandemic wave. Results: Ninety-one centres expressed interest to participate and 76 were included in the analysis, from Europe, South America, North America, Asia, and Africa (73.7%, 17.1%, 5.3%, 2.6%, and 1.3% per continent, respectively). Eighty-seven percent of the centres modified their clinical practice: 40.8% the diagnostic procedures, 80.9% the screening programme, 50% cancelled curative and/or palliative treatments for LC, and 41.7% modified the liver transplantation programme. Forty-five out of 69 (65.2%) centres in which clinical trials were running modified their treatments in that setting, but 58.1% were able to recruit new patients. The phone call service was modified in 51.4% of centres which had this service before the COVID-19 pandemic (n = 19/37). Conclusions: The first wave of the COVID-19 pandemic had a tremendous impact on the routine care of patients with liver cancer. Modifications in screening, diagnostic, and treatment algorithms may have significantly impaired the outcome of patients. Ongoing data collection and future analyses will report the benefits and disadvantages of the strategies implemented, aiding future decision-making. Lay summary: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems globally. Herein, we assessed the impact of the first wave pandemic on patients with liver cancer and found that routine care for these patients has been majorly disrupted, which could have a significant impact on outcomes