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Using angular resolved X-ray Photoelectron Spectroscopy (XPS), Magneto Optic Kerr Effect (MOKE) and X-ray Absorption Spectroscopy (XAS), we characterize the structural and magnetic evolution upon annealing of two thin Co films (8 and 9 Monolayers) deposited on Ir(111). The XAS data collected in the near Co K edge region (XANES), interpreted with ab-initio simulations, show that intermixing takes place at the Co-Ir interface. Using a linear combination analysis, we follow the intermixing during the thermally driven diffusion process. At 500 °C, the interface between Co and Ir(111) roughens slightly, but no alloy formation is detected. At 600 °C, the Co film loses integrity and MOKE data show a rearrangement of the magnetic domains. Annealing to higher temperatures results in CoxIr1- x alloy formation and Ir segregation on the surface. [ABSTRACT FROM AUTHOR]

A new tomographic reconstruction algorithm is presented, termed direct least‐squares reconstruction (DLSR), which solves the well known parallax problem in X‐ray‐scattering‐based experiments. The parallax artefact arises from relatively large samples where X‐rays, scattered from a scattering angle 2gθ, arrive at multiple detector elements. This phenomenon leads to loss of physico‐chemical information associated with diffraction peak shape and position (i.e. altering the calculated crystallite size and lattice parameter values, respectively) and is currently the major barrier to investigating samples and devices at the centimetre level (scale‐up problem). The accuracy of the DLSR algorithm has been tested against simulated and experimental X‐ray diffraction computed tomography data using the TOPAS software. [ABSTRACT FROM AUTHOR]

High-energy X-ray surface diffraction in transmission geometry is combined with a microfluidic thin layer flow cell for in situ studies of the local structure of electrodeposited epitaxial films. The capabilities of this approach are illustrated using Bi films on Au(100) single crystals as an example. We demonstrate that the local film thickness, the strain, and the orientation of the deposits' crystallites can be mapped with a spatial resolution of a few micrometers. The high heterogeneity of the Bi films provides deposits with a wide range of structural properties, allowing to establish correlations between the different parameters as a function of the local thickness. [ABSTRACT FROM AUTHOR]

Thin Co films intercalated between a Graphene capping layer and the Ir(111) surface are of interest for spintronics applications due to their peculiar magnetic properties and to their chemical stability. The structure, and then the magnetic properties, of the Co films depend on the intercalation process which is strongly influenced by the temperature, total amount of Cobalt and quality of the capping Graphene layer. In order to identify and disentangle the effects of these contributions, we report on the structural characterisation of four Co films as a function of thickness, annealing temperature, and Graphene capping. From the structural point of view, the deposition of Co on a hot Ir substrate mimics quite well the intercalation process proving the validity of the colander model describing the Graphene role during the process. [ABSTRACT FROM AUTHOR]

Germanene is a single layer allotrope of Ge, with a honeycomb structure similar to graphene. This report concerns the electrochemical formation of germanene in a pH 4.5 solution. The studies were performed using in situ Electrochemical Scanning Tunneling Microscopy (EC-STM), voltammetry, coulometry, surface X-ray diffraction (SXRD) and Raman spectroscopy to study germanene electrodeposition on Au(111) terraces. The deposition of Ge is kinetically slow and stops after 2-3 monolayers. EC-STM revealed a honeycomb (HC) structure with a rhombic unit cell, 0.44 ± 0.02 nm on a side, very close to that predicted for germanene in the literature. Ideally the HC structure is a continuous sheet, with six Ge atoms around each hole. However, only small domains, surrounded by defects, of this structure were observed in this study. The small coherence length and multiple rotations domains made direct observation with surface X-ray diffraction difficult. Raman spectroscopy was used to investigate the multi-layer Ge deposits. A peak near 290 cm-1, predicted to correspond to germanene, was observed on one particular area of the sample, while the rest resembled amorphous germanium. Electrochemical studies of germanene showed limited stability when exposed to oxygen. [ABSTRACT FROM AUTHOR]

The electrochemical formation and dissolution of the oxygen reduction reaction (ORR) PtZn catalyst on Pt(1 1 1) surface is followed by in-situ X-ray diffraction (XRD) and X-ray reflectivity (XRR) measurements. When the crystalline Pt surface is polarized to sufficiently negative potential values, with respect to an Ag/AgCl|KCl reference electrode, the electrodeposited zinc atoms diffuse into the bulk and characteristic features are observed in the X-ray patterns. The surface structure and composition during deposition and dissolution is determined from analysis of XRR curves and measurements of crystal truncation rods. Thin Zn-rich surface layer is present during the alloy formation while a Zn-depleted layer forms during dissolution. [ABSTRACT FROM AUTHOR]

The in-vitro susceptibility of Mycoplasma pneumoniae to clarithromycin, a new macrolide, was compared with that to erythromycin. A broth microdilution assay was used to evaluate 30 clinical isolates collected over a 15 year period from four countries (United States, Australia, Denmark and Japan). Clarithromycin inhibited the growth of all M. pneumoniae strains at low concentrations (≤ 0.008 mg/l) similarly to erythromycin (≤ 0.008 mg/l).In 120 outpatients with radiographically confirmed community acquired pneumonia (mean age 46-2 years), M. pneumoniae was detected culturally and/or serologically by ELISA and immunoblotting in 13% of patients, thus confirming the continued importance of this organism as a respiratory pathogen. M. pneumoniae isolates from these patients were shown to be equally susceptible to clarithromycin (≤ 0.008 mg/l) and erythromycin (≤ 0.008 mg/l). Both clarithromycin and erythromycin were effective in the treatment of community-acquired pneumonia. There were no statistically significant or clinically important differences between the two treatment groups with respect to clinical or radiographic resolution of disease or improvement in signs and symptoms. While the number of clinically evaluable patients with M. pneumoniae infections was small, both macrolides seemed equally effective. [ABSTRACT FROM PUBLISHER]

Various transport and storage conditions for the recovery of Helicobacter pylori from gastric biopsies were evaluated. Gastric mucosal biopsies from 16 Helicobacter pylori-infected patients were stored in cysteine-Albimi medium containing 20 % glycerol in a refrigerator (4°C) for 1 and 2 weeks and in a −20°C laboratory freezer for 4 and 12 weeks. Two clinical isolates were stored in saline, Stuart's transport media, cysteine-Albimi broth with 20 % glycerol, brucella broth with 20 % glycerol and skim milk with 17 % glycerol at room temperature, 4°C, −20°C and −70°C. Storage at 4°C for 1 and 2 weeks resulted in Helicobacter pylori recovery from 81 % and 19 % of biopsies, respectively. Storage at −20°C yielded Helicobacter pylori recovery in 100 % and 57 % after 4 and 12 weeks, respectively. At room temperature after 6 h, the Helicobacter pylori titer was reduced. The best storage media for frozen isolates were skim milk/glycerol, brucella broth/glycerol and cysteine-Albimi/glycerol (in descending order). Recovery was better at −70°C than −20°C. [ABSTRACT FROM AUTHOR]

The thermal stability and the structural evolution of graphene grown on Fe(110) has been studied upon annealing in ultra-high vacuum conditions (UHV, P ≤ 10 −9 mbar) and in the presence of gaseous ethylene at a pressure of ∼10 −6 mbar by grazing incidence X-ray diffraction. It was observed that upon annealing at temperatures below 630 °C, graphene on Fe is thermally stable. Exposure to ethylene at these temperatures promotes the formation of graphene while inhibiting its deterioration. Annealing graphene/Fe(110) at temperatures above 630 °C results in a fast degradation of graphene followed by carburization of the sample, that is the irreversible formation of various iron carbides, with the most common phases being Fe 3 C (cementite) and Fe 7 C 3 (Eckström-Adcock carbide). Annealing of the carburized sample does not result in the formation of a detectable graphitic structure. [ABSTRACT FROM AUTHOR]

• The Co local structure and magnetic response are closely related in Gr/Co/Ir systems. • Upon intercalation, Co local structure is isotropic. • Annealing effects on the intercalated Co depend on the film thickness. • Annealed thick films (10 MLs) retain local structural isotropy and show lower PMA. • Annealed thin films (5 MLs) present local scale anisotropy and enhanced PMA. The local atomic structure and the magnetic response of Co films intercalated between Graphene and Ir(111) were investigated combining polarized X-ray Absorption Spectroscopy at the Co K edge with Magneto-Optic Kerr Effect. The structural and magnetic evolution upon a 500 ° C annealing was evaluated as a function of the film thickness. After the thermal treatment, our thick film (10 monolayers) presented a lower perpendicular magnetic anisotropy (PMA) as well as a reduced average structural disorder. On the other hand, in our thin film (5 monolayers), the annealing enhanced the perpendicular magnetic response and induced a local anisotropy by stretching the Co-Co bonds in the film plane and compressing those outside the plane. Our finding emphasizes the close relationship between the local structure of Co within the film and its magnetic properties. [ABSTRACT FROM AUTHOR]

We investigate K-shell ionization of N2 at 40 keV photon energy. Using a cold target recoil ion momentum spectroscopy reaction microscope, we determine the vector momenta of the photoelectron, the Auger electron, and both N+ fragments. These fully differential data show that the dissociation process of the N22+ ion is significantly modified not only by the recoil momentum of the photoelectron but also by the photon momentum and the momentum of the emitted Auger electron. We find that the recoil energy introduced by the photon and the photoelectron momentum is partitioned with a ratio of approximately 30:70 between the Auger electron and fragment ion kinetic energies, respectively. We also observe that the photon momentum induces an additional rotation of the molecular ion. [ABSTRACT FROM AUTHOR]

The structure of the quasicrystalline approximant Al13Co4(100) has been determined by surface x-ray diffraction (SXRD) and complementary density-functional-theory (DFT) calculations. Thanks to the use of a two-dimensional pixel detector, which speeds up the data acquisition enormously, an exceptionally large set of experimental data, consisting of 124 crystal truncation rods, has been collected and used to refine this complex structure of large unit cell and low symmetry. Various models were considered for the SXRD analysis. The best fit is consistent with a surface termination at the puckered type of planes but with a depletion of the protruding Co atoms. The surface energy of the determined surface model was calculated using DFT, and it takes a rather low value of 1.09J/m². The results for the atomic relaxation of surface planes found by SXRD or DFT were in excellent agreement. This work opens up additional perspectives for the comprehension of related quasicrystalline surfaces. [ABSTRACT FROM AUTHOR]