Background
Long‐lasting food impactions requiring endoscopic bolus removal occur frequently in patients with eosinophilic esophagitis (EoE) and harbor a risk for severe esophageal injuries. We ...evaluated whether treatment with swallowed topical corticosteroids is able to reduce the risk of occurrence of this complication.
Methods
We analyzed data from the Swiss EoE Cohort Study. Patients with yearly clinic visits, during which standardized assessment of symptoms, endoscopic, histologic, and laboratory findings was carried out, were included.
Results
A total of 206 patients (157 males) were analyzed. The median follow‐up time was 5 years with a total of 703 visits (mean 3.41 visits/patient). During the follow‐up period, 33 patients (16 % of the cohort) experienced 42 impactions requiring endoscopic bolus removal. We evaluated the following factors regarding the outcome ‘bolus impaction’ by univariate logistic regression modeling: swallowed topical corticosteroid therapy (OR 0.503, 95%‐CI 0.255–0.993, P = 0.048), presence of EoE symptoms (OR 1.150, 95%‐CI 0.4668–2.835, P = 0.761), esophageal stricture (OR 2.832, 95%‐CI 1.508–5.321, P = 0.001), peak eosinophil count >10 eosinophils/HPF (OR 0.724, 95%‐CI 0.324–1.621, P = 0.433), blood eosinophilia (OR 1.532, 95%‐CI 0.569–4.118, P = 0.398), and esophageal dilation (OR 1.852, 95%‐CI 1.034–3.755, P = 0.017). In the multivariate model, the following factors were significantly associated with bolus impaction: swallowed topical corticosteroid therapy (OR 0.411, 95%‐CI 0.203–0.835, P = 0.014) and esophageal stricture (OR 2.666, 95%‐CI 1.259–5.645, P = 0.01). Increasing frequency of use of swallowed topical steroids was associated with a lower risk for bolus impactions.
Conclusions
Treatment of EoE with swallowed topical corticosteroids significantly reduces the risk for long‐lasting bolus impactions.
The high crystallinity of many inorganic materials allows their band structures to be determined through angle-resolved photoemission spectroscopy (ARPES). Similar studies of conjugated organic ...molecules of interest in optoelectronics are often hampered by difficulties in growing well-ordered and well-oriented crystals or films. We have grown crystalline films of uniaxially oriented sexiphenyl molecules and obtained ARPES data. Supported by density-functional calculations, we show that, in the direction parallel to the principal molecular axis, a quasi-one-dimensional band structure of a system of well-defined finite size develops out of individual molecular orbitals. In contrast, perpendicular to the molecules, the band structure reflects the periodicity of the molecular crystal, and continuous bands with a large dispersion were observed.
Photoemission spectroscopy is commonly applied to study the band structure of solids by measuring the kinetic energy versus angular distribution of the photoemitted electrons. Here, we apply this ...experimental technique to characterize discrete orbitals of large π-conjugated molecules. By measuring the photoemission intensity from a constant initial-state energy over a hemispherical region, we generate reciprocal space maps of the emitting orbital density. We demonstrate that the real-space electron distribution of molecular orbitals in both a crystalline pentacene film and a chemisorbed p-sexiphenyl monolayer can be obtained from a simple Fourier transform of the measurement data. The results are in good agreement with density functional calculations.
The growth and geometric structure of ultrathin zinc oxide films on Pd(111) has been studied by scanning tunneling microscopy, low-energy electron diffraction, and density functional theory ...calculations. For sub-monolayer coverages, depending on the oxygen pressure, two well-ordered zinc oxide phases with (4 × 4) and (6 × 6) coincidence structures form, which are attributed to H-terminated Zn6O5 and graphite-like Zn6O6 layers, respectively. The (6 × 6) phase exhibits a pronounced oxygen pressure dependence: at low p(O2) a well-ordered (6 × 6) two-dimensional array of O vacancies develops, yielding a layer with a formal Zn25O24 stoichiometry, while at high p(O2) the Zn6O6 monolayer transforms into bilayer islands. For oxide coverages up to 4 monolayers the graphite-like Zn6O6 structure is thermodynamically the most stable phase over a large range of oxygen chemical potentials, before it converges to the bulk-type wurtzite structure. Under oxygen-poor conditions a compressed overlayer of Zn adatoms can be stabilized on top of the Zn6O6 structure.
The oxidation of vanadium nitride (VN) and titanium nitride (TiN) coatings in ultra-high vacuum has been investigated in situ by X-ray photoelectron spectroscopy. On the VN coatings mixed oxide ...layers containing V
3+ and V
4+ species form at elevated temperatures (⩾600°C) and at high oxygen exposures, which cover completely the VN surface. Under similar oxidation conditions the TiN surface oxidises partially to a mixture of TiO
2 and Ti oxynitride (TiO
x
N
y
) phases. This oxidation behaviour has been correlated to the tribological properties of the VN and TiN coatings investigated recently.
Metal tungstates (with general formula MWO4) are functional materials with a high potential for a diverse set of applications ranging from low-dimensional magnetism to chemical sensing and ...photoelectrocatalytic water oxidation. For high level applications, nanoscale control of film growth is necessary, as well as a deeper understanding and characterization of materials properties at reduced dimensionality. We succeeded in fabricating and characterizing a two-dimensional (2-D) copper tungstate (CuWO4). For the first time, the atomic structure of an ultrathin ternary oxide is fully unveiled. It corresponds to a CuWO4 monolayer arranged in three sublayers with stacking O–W–O/Cu from the interface. The resulting bidimensional structure forms a robust framework with localized regions of anisotropic flexibility. Electronically it displays a reduced band gap and increased density of states close to the Fermi level with respect to the bulk compound. These unique features open a way for new applications in the field of photo- and electrocatalysis, while the proposed synthesis method represents a radically new and general approach toward the fabrication of 2-D ternary oxides.
The exceptional physical properties of graphene have sparked tremendous interests toward two-dimensional (2D) materials with honeycomb structure. We report here the successful fabrication of 2D iron ...tungstate (FeWO x ) layers with honeycomb geometry on a Pt(111) surface, using the solid-state reaction of (WO3)3 clusters with a FeO(111) monolayer on Pt(111). The formation process and the atomic structure of two commensurate FeWO x phases, with (2 × 2) and (6 × 6) periodicities, have been characterized experimentally by combination of scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD) and understood theoretically by density functional theory (DFT) modeling. The thermodynamically most stable (2 × 2) phase has a formal FeWO3 stoichiometry and corresponds to a buckled Fe2+/W4+ layer arranged in a honeycomb lattice, terminated by oxygen atoms in Fe–W bridging positions. This 2D FeWO3 layer has a novel structure and stoichiometry and has no analogues to known bulk iron tungstate phases. It is theoretically predicted to exhibit a ferromagnetic electronic ground state with a Curie temperature of 95 K, as opposed to the antiferromagnetic behavior of bulk FeWO4 materials.
Lattice Strain Defects in a Ceria Nanolayer Ma, Liying; Doudin, Nassar; Surnev, Svetlozar ...
The journal of physical chemistry letters,
04/2016, Volume:
7, Issue:
7
Journal Article
Peer reviewed
Open access
An ultrathin two-dimensional CeO2 (ceria) phase on a Cu(110) surface has been fabricated and fully characterized by high-resolution scanning tunneling microscopy, photoelectron spectroscopy, and ...density functional theory. The atomic lattice structure of the ceria/Cu(110) system is revealed as a hexagonal CeO2(111)-type monolayer separated from the Cu(110) surface by a partly disordered Cu–O intercalated buffer layer. The epitaxial coupling of the two-dimensional ceria overlayer to the Cu(110)-O surface leads to a nanoscopic stripe pattern, which creates defect regions of quasi-periodic lattice distortions. The symmetry and lattice mismatch at the interface is clarified to be responsible for the topographic stripe geometry and the related anisotropic strain defect regions at the ceria surface. This ceria monolayer is in a fully oxidized and thermodynamically stable state.
Surnev et al examined the structure-property relationship, in addition to the chemical aspects, of oxide-metal hybrid nanostructures. They explain the coupling of nanostructures of the oxide to the ...metal surface and discuss various methods for understanding the chemical aspects and structure-property relationships.
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