Simultaneous Projectile-Target Ionization: A Novel Approach to (e, 2e) Experiments on Ions

A kinematically complete experiment for simultaneous ionization of a projectile and target has been performed for 3.6 MeV/u C2+ on He collisions measuring the final vector momenta of the He1+ recoil ion and of two electrons (projectile, target) in coincidence with the emerging C3+ projectile. The feasibility of an event-by-event separation of the various reaction channels, among them the ionization of C2+ by the interaction with a quasifree target electron, is demonstrated in agreement with six-body classical trajectory Monte Carlo calculations, paving the way to kinematically complete electron-ion scattering experiments

Fully Printed Inverters using Metal‐Oxide Semiconductor and Graphene Passives on Flexible Substrates

Printed and flexible metal‐oxide transistor technology has recently demonstrated great promise due to its high performance and robust mechanical stability. Herein, fully printed inverter structures using electrolyte‐gated oxide transistors on a flexible polyimide (PI) substrate are discussed in detail. Conductive graphene ink is printed as the passive structures and interconnects. The additive printed transistors on PI substrates show an $_{on}$/$_{off}$ ratio of 10$^{6}$ and show mobilities similar to the state‐of‐the‐art printed transistors on rigid substrates. Printed meander structures of graphene are used as pull‐up resistances in a transistor–resistor logic to create fully printed inverters. The printed and flexible inverters show a signal gain of 3.5 and a propagation delay of 30 ms. These printed inverters are able to withstand a tensile strain of 1.5% following more than 200 cycles of mechanical bending. The stability of the electrical direct current (DC) properties has been observed over a period of 5 weeks. These oxide transistor‐based fully printed inverters are relevant for digital printing methods which could be implemented into roll‐to‐roll processes

Correlated Three-Electron Continuum States in Triple Ionization by Fast Heavy-Ion Impact

We have performed a kinematically complete experiment for triple ionization in atomic collisions. Data were obtained for 3.6-MeV/amu Au53+ impact on Ne. A specific Dalitz representation was developed allowing one to plot in a single spectrum the energy of all three ionized electrons and, simultaneously, obtain information on their emission angles with respect to the projectile direction. The data show distinct fragmentation patterns favoring very asymmetric energy partitionings with one fast and two slow electrons. They are compared to various Classical Trajectory Monte Carlo (CTMC) models. The experimental results are well described only if the electron-electron interaction is included throughout the collision and surprisingly, if the classically modeled electrons are fully correlated in the initial state

Electron Angular Distributions in He Single Ionization Impact by H₂⁺ Ions at 1 MeV

For the first time we investigated in a kinematically complete experiment the ionization of helium in collisions with H2+-molecular ions at 1 MeV. Using two separate detectors, the orientation of the projectile H2+-molecular ions was determined at the instance of the collision. The electron angular distribution was measured by a Reaction Microscope . The observed structures are found in agreement with theoretical calculations, indicating that the ionized electron of He shows a slight preferential emission direction parallel to the molecular axis

Projectile-Charge Sign Dependence of Four-Particle Dynamics in Helium Double Ionization

Double ionization of helium by 6 MeV proton impact has been explored in a kinematically complete experiment using a “reaction microscope.” For the first time, fully differential cross sections for positively charged projectiles have been obtained and compared with data from 2 keV electron impact. The significant differences observed in the angular distribution of the ejected electrons are attributed to the charge sign of the projectile, resulting in different dynamics of the four-particle Coulomb system, which is not considered in the first Born approximation

Mutual Projectile and Target Ionization in 1-MeV/amu N⁴⁺ and N₅⁺+ He Collisions

We have studied mutual projectile and target ionization in 1-MeV/amu N4+ and N5++He collisions in kinematically complete experiments by measuring the momenta of the recoil ion and both ejected electrons in coincidence with the charge-changed projectiles. By means of four-particle Dalitz plots, in which multiple differential cross sections are presented as a function of the momenta of all four particles, experimental spectra are compared with theoretical results from various models. The experimental data are qualitatively reproduced by higher-order calculations, where good agreement is achieved for N5++He collisions, while some discrepancies persist for N4++He collisions

Challenges of drug resistance in the management of pancreatic cancer

The current treatment of choice for metastatic pancreatic cancer involves single agent gemcitabine or combination of gemcitabine with capecitabine and erlotinib (tyrosine kinase inhibitor). Only 25-30% of patients respond to this treatment and patients who do respond initially ultimately exhibit disease progression. Median survival for pancreatic cancer patients has reached a plateau due to inherent and acquired resistance to these agents. Key molecular factors implicated in this resistance include: deficiencies in drug uptake, alteration of drug targets, activations of DNA repair pathways, resistance to apoptosis, and the contribution of the tumor microenvironment. Moreover, for newer agents including tyrosine kinase inhibitors, over expression of signaling proteins, mutations in kinase domains, activation of alternative pathways, mutations of genes downstream of the target, and/or amplification of the target represent key challenges for treatment efficacy. Here we will review the contribution of known mechanisms and markers of resistance to key pancreatic cancer drug treatments

Electron Loss from 1.4-MeV / u U\u3csup\u3e4,6,10+\u3c/sup\u3e Ions Colliding with Ne, N₂, and Ar Targets

Absolute, total, single- and multiple-electron-loss cross sections are measured for 1.4-MeV / u U4,6,10+ ions colliding with neon and argon atoms and nitrogen molecules. It is found that the cross sections all have the same dependence on the number of electrons lost and that multiplying the cross sections by the initial number of electrons in the 6s, 6p, and 5f shells yields good agreement between the different projectiles. By combining the present data with previous measurements made at the same velocity, it is shown that the scaled cross sections slowly decrease in magnitude for incoming charge states between 1 and 10, whereas the cross sections for higher-charge-state ions fall off much more rapidly