Real-Time Imaging of On-Surface Ullmann Polymerization Reveals an Inhibiting Effect of Adatoms.

Ullmann coupling is a widely used reaction for the on-surface growth of low-dimensional carbon nanomaterials. The irreversible nature of this reaction prevents the "self-healing" of defects, and a detailed knowledge of its mechanism is therefore essential to enable the growth of extended ordered structures. However, the dynamics of the Ullmann polymerization remain largely unexplored, as coupling events occur on a timescale faster than conventional scanning probe microscopy imaging frequencies.

Spin-Dependent ππ^{*} Gap in Graphene on a Magnetic Substrate.

We present a detailed analysis of the electronic properties of graphene/Eu/Ni(111). By using angle- and spin-resolved photoemission spectroscopy and ab initio calculations, we show that the intercalation of Eu in the graphene/Ni(111) interface gives rise to a gapped freestanding dispersion of the ππ^{*} Dirac cones at the K[over ¯] point with an additional lifting of the spin degeneracy due to the mixing of graphene and Eu states. The interaction with the magnetic substrate results in a large spin-dependent gap in the Dirac cones with a topological nature characterized by a large Berry curvature and a spin-polarized Van Hove singularity, whose closeness to the Fermi level gives rise to a polaronic band.

Mechanistic insights into on-surface reactions from isothermal temperature-programmed X-ray photoelectron spectroscopy.

On-surface synthesis often proceeds under kinetic control due to the irreversibility of key reaction steps, rendering kinetic studies pivotal. The accurate quantification of reaction rates also bears potential for unveiling reaction mechanisms. Temperature-Programmed X-ray Photoelectron Spectroscopy (TP-XPS) has emerged as an analytical tool for kinetic studies with splendid chemical and sufficient temporal resolution.

Risk Factors for Failure of Endoscopic Balloon Dilatation of Primary Obstructive Megaureter: Single-Center 12-Year Experience with 123 Cases.

To review our experience with >100 patients with primary obstructive megaureter (POM) undergoing endoscopic balloon dilatation (EBD) and a follow-up of up to 12 years and determine potential risk factors for failure. Our hypothesis is that EBD allows for long-term treatment in >80% of patients, and its effectiveness decreases in more severe cases. This is a retrospective study of 123 consecutive patients (131 ureters) undergoing EBD from 2009 to 2021.