The graphene/n-Ge(110) interface: structure, doping, and electronic properties.

The implementation of graphene in semiconducting technology requires precise knowledge about the graphene-semiconductor interface. In our work the structure and electronic properties of the graphene/n-Ge(110) interface are investigated on the local (nm) and macro (from µm to mm) scales via a combination of different microscopic and spectroscopic surface science techniques accompanied by density functional theory calculations. The electronic structure of freestanding graphene remains almost completely intact in this system, with only a moderate n-doping indicating weak interaction between graphene and the Ge substrate. With regard to the optimisation of graphene growth it is found that the substrate temperature is a crucial factor, which determines the graphene layer alignment on the Ge(110) substrate during its growth from the atomic carbon source. Moreover, our results demonstrate that the preparation route for graphene on the doped semiconducting material (n-Ge) leads to the effective segregation of dopants at the interface between graphene and Ge(110). Furthermore, it is shown that these dopant atoms might form regular structures at the graphene/Ge interface and induce the doping of graphene. Our findings help to understand the interface properties of the graphene-semiconductor interfaces and the effect of dopants on the electronic structure of graphene in such systems.

Lacosamide in the treatment of patients with epilepsy and intellectual disabilities: A long-term study of 136 patients.

OBJECTIVE: This study aimed to analyze the retention rate of lacosamide (LCM) in patients with epilepsy and intellectual disabilities (IDs), to identify factors influencing retention rate, and to investigate the LCM retention rate with and without concomitant sodium channel blocker (SCB). We hypothesized that the retention rate of LCM with concomitant SCB would be lower than without SCB. METHODS: Using the Kaplan-Meier estimator, we conducted a monocentric, retrospective, observational, open-label study to evaluate LCM retention rates in patients with IDs and drug-resistant epilepsy. In addition, the impact of therapy-related variables on the long-term retention of LCM was evaluated. RESULTS: One hundred thirty-six subjects with IDs and drug-resistant epilepsy were included (age 2-66 years); most patients had focal epilepsy. Long-term retention rates were 62.0% at 1 year, 43.7% at 2 years, and 29.1% at 3 and 4 years. Reasons for LCM discontinuation included insufficient therapeutic benefits (69%), adverse events (11%), or a combination of both factors (8%). The LCM retention rate was influenced by the number of background antiepileptic drugs (AEDs). An additional and independent influence of concomitant therapy with SCB on retention rate could not be confirmed. SIGNIFICANCE: One of the major challenges in medically caring for patients with epilepsy and IDs is the high rate of drug resistance. However, there is a lack of evidence-based information about the efficacy and tolerability of AEDs in this population. It has been shown that concomitant SCB use is a key factor in increasing the risk of LCM failure in children with epilepsy. This finding has not been replicated in our predominantly adult sample of patients with IDs.

Adsorption of Water and Ammonia on Graphene: Evidence for Chemisorption from X-ray Absorption Spectra.

While the bonding of molecular adsorbates to graphene has so far been characterized as physisorption, our study of adsorbed ammonia and water using near-edge X-ray absorption spectroscopy provides unambiguous evidence for a chemical contribution to the adsorption bond. We use the situation, unique to graphene, to characterize the unoccupied valence band states of the partners in the bond on the basis of the complementary adsorbate and substrate X-ray absorption K edges. New adsorbate-induced features on the substrate (carbon) K edge are interpreted as hybrid states in terms of a simple model of chemical interaction.

Graphene on ferromagnetic surfaces and its functionalization with water and ammonia.

In this article, an angle-resolved photoelectron spectroscopy (ARPES), X-ray absorption spectroscopy (XAS), and density-functional theory (DFT) investigations of water and ammonia adsorption on graphene/Ni(111) are presented. The results of adsorption on graphene/Ni(111) obtained in this study reveal the existence of interface states, originating from the strong hybridization of the graphene π and spin-polarized Ni 3d valence band states. ARPES and XAS data of the H2O (NH3)/graphene/Ni(111) system give an information regarding the kind of interaction between the adsorbed molecules and the graphene on Ni(111). The presented experimental data are compared with the results obtained in the framework of the DFT approach.