Search

In our paper(1) the N 1s core level energy as obtained by Al Kα excited X-ray photoelectron spectroscopy (XPS) of boron nitride on Ru(0001) is not correctly reproduced, it is 398.63 ± 0.15 eV and not 389.63 ± 0.15 eV. Table 1 reproduces the B 1s and N 1s binding energies and work functions for h-BN on Rh(111), Ru(0001), Ni(111), and Pd(111).(2)Figure 1 reproduces the corresponding core level data with the correct energy scale. We are grateful to W. Auwarter for spotting these inconsistencies.

Das Thoraxtrauma und die schwere, nicht traumatische bedingte Dyspnoe stellen eine besondere Herausforderung an die Thoraxsonographie dar, indem einige lebensbedrohliche Situationen sofort erkannt und auch interventionell behandelt werden konnen. Dabei gehen wir nach dem international anerkannten ABC-Standard vor. Behinderungen der Atemwege und Atmung haben Vorrang vor Storungen von Herz und Zirkulation. Haufige und wichtige Ursachen der Dyspnoe konnen gut mittels Ultraschall erkannt und dargestellt werden. Allerdings ist die Methode nicht 100 % sensitiv sowie spezifisch, und einige wenige Pathologien oder deren Lokalisation sind dem Thoraxultraschall nicht zuganglich. Zudem wird das Verfahren immer wichtiger, da vermehrt relative Kontraindikationen fur die CT-Untersuchung vorkommen.

For many years, the FAST examination has represented the standard procedure for diagnostics in traumatology. Until just recently, the ultrasound societies in German speaking countries did not recognize this procedure, which is the reason why it has not been included in current educational programs. The acronym FAST stands for «Focused Assessment with Sonography for Trauma» and is defined as the sonographic detection of free fluid in the intraperitoneal, pleural and pericardial spaces in patients who have suffered blunt or penetrating trauma. The extension to eFAST («extended FAST») in the year 2004 to include the additional diagnosis of pneumothorax marked the beginning of the procedure's meteoric development. Nowadays, everybody is talking about FAST-plus in reference to a broad range of applications within the field of airway management, organ injury diagnostics, cerebral hypertension as well as support for invasive procedures. However, the continued rise of FAST will depend on the future role that computed tomography (CT) will be playing. Indeed, it remains unclear whether CT utilized as FACTT («Focused Assessment with Computed Tomography in Trauma») will force out FAST and advance to become the diagnostic gold standard.

Jährlich kommt es in der Schweiz bei Erwachsenen zu rund 250 schweren oder tödlichen Vergiftungen, bei Kindern sind dies ca. 25 (Beratungen des Schweiz. Toxikologischen Informationszentrums). Patienten mit lebensbedrohlichen Symptomen benötigen sofort intensivmedizinische Maßnahmen auf symptomatischer Basis, auch wenn die der Vergiftung zugrunde liegende Noxe noch nicht bekannt ist. Dabei wird das Notfall-ABCDE angewendet (Airway, Breathing, Circulation, Disabilities, Exposure). Die Abklärung der Vergiftungsursache (Identifikation der Noxe) und die weiteren Untersuchungen (EKG, Labor, Röntgen) werden parallel dazu vorangetrieben, und die Ergebnisse werden laufend in der weiteren Therapie berücksichtigt. Bei der Wahl der Behandlungsmodalitäten ist darauf zu achten, dass sie nicht ungünstig mit bekannten oder potentiellen Noxen interagieren und damit die Vergiftung noch verschlimmern. Spezifische Massnahmen können nur ergriffen werden, wenn die Noxen bekannt sind, oder wenn durch die Erkennung eines Toxidroms die Substanzgruppe soweit eingeschränkt werden kann, dass eine gezielte Behandlung möglich ist.

We present the design and performance tests of a miniaturized pulsed low-energy electron gun. Electrons photoemitted from a gold cathode are accelerated over a distance of 75 μm and then collimated by a microchannel plate. According to calculations, this novel concept will allow the time spread of the electron pulses to be kept below 5 ps for kinetic energies as low as 100 eV. The achievement of a minimum angular beam divergence (≈1°) along with an energy resolution of 1.1 eV has to be paid for by low signal intensities. We demonstrate the performance of the gun and the high electron-beam coherence by presenting low-energy-electron diffraction images taken from a submonolayer of lead adsorbed on the germanium (111) surface. We anticipate that this electron gun will open up new possibilities for following structural changes on solid surfaces in real time.

The orientation and the intramolecular relaxation due to adsorption of the chiral phenanthrene-derivative heptahelicene, C30H18, on Cu(111) and Cu(332) surfaces have been investigated by means of angle-scanned full-hemispherical x-ray photoelectron diffraction. Although the C 1s diffraction patterns of the adsorbed submonolayer coverage helicene films exhibit scattering anisotropies of less than two percent, a detailed analysis involving simple molecular mechanics calculations of the atomic coordinates, photoelectron diffraction single-scattering cluster calculations and an R-factor analysis permits the determination of the helicene molecular orientation. On Cu(111), the molecules are found to bind to the substrate surface via their terminal phenanthrene group oriented parallel to the surface plane, while on Cu(332) the three terminal C-6 rings are oriented parallel to the (111) terrace plane. Six azimuthal molecular orientations are found to coexist on Cu(111), on Cu(332), however, the step–molecule inte...

The setup of an electron spectrometer for angle-resolved photoemission is described. A sample goniometer offers the opportunity for angle scanned photoemission over 2π solid angle above the surface. A monochromatized high flux He discharge photon source is exploited to measure thermally populated electronic states above the Fermi level EF. At energies greater than EF+5kBT the signal from a constant density of states declines below the photoelectron background caused by photons with higher energies than He Iα (21.2 eV). For He IIα (40.8 eV) the residual photoelectron background is lower and photoemission up to 6kBT above EF can be performed. Data showing two cuts through the Fermi surface of silver are presented. Furthermore the dispersion of the Shockley surface state on Ag (111) above the Fermi energy is quantified.

This adult cohort determined the incidence and patients' short-term outcomes of severe traumatic brain injury (sTBI) in Switzerland and age-related differences. A prospective cohort study with a follow-up at 14 days was performed. Patients ≥16 years of age sustaining sTBI and admitted to 1 of 11 trauma centers were included. sTBI was defined by an Abbreviated Injury Scale of the head (HAIS) score >3. The centers participated from 6 months to 3 years. The results are presented as percentages, medians, and interquartile ranges (IQRs). Subgroup analyses were performed for patients ≤65 years (younger) and >65 (elderly). sTBI was observed in 921 patients (median age, 55 years; IQR, 33–71); 683 (74.2%) were male. Females were older (median age, 67 years; IQR, 42–80) than males (52; IQR, 31–67; p

OBJECTIVES: Liquid manure systems and manure pits are major hazards in the agricultural workplace. The incidence of accidents related to manure is unknown. The objective of this study was to survey the liquid manure facilities of farms in eastern Switzerland and find the incidence of accidents related to manure in the region. METHODS: Retrospective cohort study and cross sectional survey of 210 farms in eastern Switzerland. RESULTS: The incidence of accidents related to manure was found to be 10.4/1000 person-years. Most accidents were categorised as minor--that is, had a benign outcome for the people involved or involved animals only. One in 33 of the farms surveyed was the scene of an accident related to manure each year. CONCLUSIONS: The medical literature on accidents related to manure mostly reports accidents with catastrophic outcomes. This study shows that this type of accident is only the tip of the iceberg. Most of the accidents reported in this study belong to a category that has hitherto been un-noticed and unreported. The term "accident related to manure" covers a broad range of events, and those resulting in serious human illness or death represent only a small part of this spectrum. A wide variety of liquid manure systems were found on the farms surveyed. Very few liquid manure facilities conformed to published safety standards.

The structural sensitivity of x-ray photoelectron diffraction is greatly enhanced by the acquisition of a full hemispherical diffraction pattern of chemically shifted core levels. Complex systems can be studied resolving the local order per element and per chemical environment. This technique is applied to study the earliest stages of hydrogenated diamondlike carbon film deposition on Si(001). Effects of the sample temperature and ion dose on the structure of deposited layers are discussed.

Although significant insight into fullerene-substrate interactions has come from recent surface science studies, to date there has been no unambiguous way to determine the molecular orientation of adsorbed C 60 molecules. We show that photoelectron diffraction patterns from monolayer C 60 films are directly related to the intramolecular structure of C 60. This allows for the first time a direct and unambiguous identification of the molecular orientation of the adsorbed fullerenes with respect to the substrate. A variety of molecular orientations is observed on different substrates. [S0031-9007(96)00473-5]

A brief survey is given on the current state-of-the-art of this surface structural technique based on photoelectron spectroscopy, with particular emphasis on the progress that has been made recently by routinely measuring full-hemispherical intensity distributions. We limit the discussion to the photoelectron forward focusing regime, which is attained at electron kinetic energies of a few hundred eV. Surface bond directions are directly revealed as pronounced maxima in the angular distributions from subsurface atoms, while characteristic interference features are observed for surface species. For both cases the dependence on the atomic type is weak enough so that these features provide a fingerprint of the local bonding geometry. For surface and near-surface species, this may then serve as a starting point for a structure refinement using single-scattering cluster calculations. Selected examples are given for illustrating these procedures.

The spatial distribution of quasi-elastically back-scattered electrons from single-crystalline YBa 2 Cu 3 O x (001), a high- T c superconductor ( T c = 91 K), has been measured at 2 keV energy with high angular resolution (1°). The data are presented as a full-hemispherical intensity map. It is characterized by a fourfold symmetry and resembles the Kikuchi pattern of a bcc crystal. These data are compared with single-scattering cluster simulations performed with structural models for the near-surface layers identical to those in the bulk and for different types of the crystal termination. Rather good agreement is found when the cluster is sufficiently large (more then 700 atoms) indicating that at room temperature the investigated near-surface layers have a local structure similar to the bulk one.

X-ray photoelectron diffraction has been used to investigate the interfaces of Ni/diamond, Si/diamond and Au/diamond. These elements were evaporated in UHV on doped and undoped diamond (100) and (111) substrates at different temperatures. While Ni grows heteroepitaxially on the diamond surface no orientation was observed for Si and Au. The Si/diamond interface shows no carbide formation even when heating to 850 °C. However, the C 1s peak of the diamond substrate shifts to lower binding energy when evaporating Si. This could possibly be explained by band bending at the interface. Ni, Si and Au form islands at these low film coverages.

Core-level X-ray photoelectron-diffraction patterns have been measured from cleaved Bi2Sr2CaCu2O8+δ (001) surfaces for all elements present in this compound. The incommensurate modulation alongb ([010]) leads to a strong inequivalence ofa- andb-directions for Bi, Sr and Cu photoelectrons, while Ca and O emission show less effect. Ultraviolet-photoemission experiments recording the emission intensity at the Fermi energy over a large solid angle are also presented, providing a direct mapping of the Fermi surface. Ac(2×2) superstructure is observed on the Fermi surface suggesting antiferromagnetic correlations within the Cu−O planes. The effects of the lattice modulation are clearly observable at the Fermi energy, and they are enhanced for binding energies higher than a few tens of meV.

This critical analysis of the traditional pathophysiological approach to the diagnosis and treatment of cardiogenic pulmonary edema calls into question some long-established ideas and interventions that ought to be replaced by better evidence-based concepts.

Angular distributions of x-ray-excited Na 1s photoelectrons and Na KVV Auger electrons emitted from c(2\ifmmode\times\else\texttimes\fi{}2)-Na/Al(001) have been measured over the full 2\ensuremath{\pi} solid angle above the Al(001) surface. A detailed study involving single-scattering cluster calculations and an R-factor analysis has been performed to determine the room-temperature adsorption site of Na on Al(001). The best agreement with experiment is obtained for a configuration in which domains of Na atoms adsorbed in the hollow site and in the substitutional site coexist on the surface. This unusual and unexpected behavior has not been observed for an alkali-metal-on-metal adsorption system up to now, but it can be understood on the basis of very recent results from first-principles density-functional theory [C. Stampfl, J. Neugebauer, and M. Scheffler, Surf. Rev. Lett. 1, 222 (1994)].

Natural diamond (001) and (111) surfaces as well as highly oriented pyrolithic graphite (HOPG) (0001) have been analyzed by X-ray induced photoelectron diffraction (XPD). The measured 2π patterns of C Is emission (964 and 1450 eV) and of KVV Auger emission (260 eV) are compared to single scattering cluster (SCC calculations, and excellent agreement is found. The comparisons show that photoelectron forward focusing is much less prominent in carbon solids than in all previously studied, heavier elements, and a direct interpretation of the data is therefore more difficult. The highly textured nature of HOPG presents itself as a circular pattern with concentric rings centered at the surface normal ( c -axis). The aim of this work is to show the advantage of the XPD technique as a diagnostic tool for the investigation of epitaxial diamond growth with monolayer sensitivity.

The full-solid-angle (2\ensuremath{\pi}) intensity maps of the carbon-KVV Auger-electron emission at 260 eV from diamond (111), diamond (100), and highly oriented pyrolitic graphite (HOPG) (0001) samples were collected and compared with spherical-wave single-scattering cluster calculations. In contrast to Mg K\ensuremath{\alpha} excited C 1s patterns the C-KVV patterns show weak direct real-space information. We performed a detailed angular momentum analysis taking into account different l characters of the emitted Auger electrons and show that in diamond the C-KVV emission has mainly a d-like character while graphite emits a mixture of p- and d-like electrons with a minor contribution of s-like electrons.

Real space image formation in photoelectron holography is discussed using a reconstruction formalism based on the Helmholtz-Kirchhoff theorem in spherical coordinates. In this representation it is readily understood under which conditions reliable atomic images are formed and when artifacts prevail. In multilayer substrate emission, at energies of a few hundred eV and above where forward scattering amplitudes dominate the diffraction patterns, no atomic images are obtained and the structures observed in real space coordinates are formed due to the symmetry of the crystal lattice. This is illustrated by a comparison of holographic reconstructions of data from diamond (111) and Si(111) surfaces. On the other hand, forward scattering is absent in diffraction patterns obtained from adsorbate species situated on top of the surface. For c(2×2) Na/Al(001) we clearly observe images of first and second nearest in-plane neighbours.

Electrons with kinetic energies between 600 eV and 1.5 keV have been diffracted at the surface of a Cu(111) crystal. The intensity of the electron wavefield within the crystal has been measured using low-energy Cu M 2,3 VV Auger electrons integrated over a large solid angle. The results are well reproduced by single-scattering calculations. We show that this technique is chemically selective as well as sensitive to the crystal structure and that it is essentially the time reversal of X-ray photoelectron diffraction but in general more surface-sensitive than the latter. It is therefore well suited to study epitaxial growth and interdiffusion.

High resolution angle resolved photoemission spectra from potassium adsorbed on a single-domain Si(100)2 × 1 surface show K-derived states near the Fermi level. The metallization occurs when half a monolayer of K is deposited and a maximum decrease in the work function is observed. At slightly lower K coverage, the surface is still semiconducting. The metallic K-derived state presents non-parabolic-like dispersions in the directions along and perpendicular to the dimer rows, showing a behavior rather different to the one observed for alkali adsorption on metals.

While photoelectron spectroscopy has been demonstrated to be useful for the determination of Fermi surfaces of two-dimensional systems we discuss the possibility to characterize a fully three-dimensional metal in this manner. Angular distributions of valence photoelectrons at UV energies integrated over a small energy window at the Fermi energy are measured over a large part of the 2π hemisphere for the case of Cu(001), Cu(111) and Cu(110). They are compared to the model of direct transitions from bulk bands crossing the Fermi energy to empty bands. The observed patterns show the proper translational symmetry with respect to the Brillouin zone (BZ). We conclude that the measurements represent a well defined cut through the Fermi surface.

An 8 monolayer Ag film has been deposited in situ on Cu(001) at room temperature. Its structure has been investigated by X-ray photoelectron diffraction, presented as full solid-angle intensity maps, and by low-energy electron diffraction. The formation of a compact Ag(111)-like overlayer with one preferential domain has been observed. Annealing the Ag film at about 300 o C creates Ag islands on the Cu(001) substrate. The system is put into the context of eight other noble-metal (Ag, Au and Pt) films deposited on different substrates (Cu, Pt, Cu 3 Au, Bi 2 Sr 2 CaCu 2 O 8+x ). The crystalline orientation of the overlayers with respect to the substrate and the formation of a surface alloy are discussed

We have applied XPD (X-ray photoelectron diffraction) to the surfaces of W(001)c(2 × 2)-Au and -Ag. Au4f and Ag3d XPD patterns have been measured for the two c(2 × 2) surfaces at electron take-off angles of 4°–22°. It is found that both Au 4f and Ag 3d XPD patterns are very similar to each other showing that the two surfaces have essentially the same structure. Consideration of the general properties of XPD, coverage and bond-lengths of the constituent atoms led to two plausible models (surface-alloy and overlayer models) for the surfaces. We have tested the two models by kinematical analyses of the XPD patterns for the W(001)c(2 × 2)-Au surface using either an s-symmetry and spherical-wave formula or a formula with spherical and dipole-selected final states. It has turned out that although the surface-alloy model is more plausible, the kinematical calculations for the two models do not reproduce the details of the experiment indicating the importance of multiple scattering of electrons for these surfaces consisting of high-Z atoms.

The dissolution of Pt/Cu(111) and the kinetic blocking of the dissolution process which results in the formation of a surface alloy have been studied. We use AES, PES, XPD, and LEED to characterise the non-classical dissolution behaviour. Chemical shifts on the Pt 4f72 and the Cu 3p core levels are measured during dissolution. The top layer of the surface alloy is Cu3Pt for an annealing temperature of 315°C. For the higher annealing temperature of 350°C the Pt concentration is smaller. The alloy composition is therefore temperature dependent and the formation of a relatively stable alloy in local equilibrium over the surface layers is determined by the segregation and ordering behaviour. The chemical ordering of the surface alloy and its electronic structure remains to be verified.

Using GaAs/AlAs/GaAs heterostructures we report measurements of complete hemispheric Auger-electron diffraction patterns originating from single well-defined subsurface sites within a crystal lattice. With this data set a detailed experimental analysis of multiple elastic-scattering effects is performed. We investigate the dependence of the forward enhancement factor along atomic chains on the length and on the internal structure of the chain. No randomization of the elastically scattered electrons is observed even for long traveling path lengths. The angle-dependent features related to elastic scattering as well as those originating from inelastic scattering are evaluated independently to obtain depth profiles of the electron-emitting atoms. Both types of depth profiles indicate a microscopic redistribution of Al and Ga in a surface region of one bilayer thickness.

A detailed experimental study of the effect of angular resolution on the line widths of transitions from Cu(001) is presented. We find a dramatic narrowing of the direct transition lines from the volume sp band when reducing the angular acceptance cone much below 1° to an ultimate value of a few tenths of a degree. This effect occurs for transitions located in the 2nd Brillouin zone (BZ) and for the d band surface state near the M point of the surface BZ, whereas such a strong effect is not observed for transitions from sp bands in the first BZ. In the 2nd BZ we obtain widths of 0.25eV as close as 1.0eV from the Fermi edge, while previously published widths for transitions from the 1st BZ are of the order of 0.7eV or more for the Cu sp transitions. We find a more or less linear increase of line width as the Fermi level is approached.

Angular distributions of several photoelectron and Auger transitions have been measured above a Cu(001) single crystal at 16 different kinetic energies between 60 and 1740 eV. The results are presented as 2π full-solid-angle intensity maps-diffractograms-that permit a clear representation of the relative importance of various scattering processes at each energy and the evolution of intensity patterns with energy. The experiments are compared with single-scattering-cluster (SSC) simulations performed at corresponding energies

Auger data shows a layer by layer growth of Pt/Cu(111) for the first three monolayers at room temperature. Surface core level photoemission spectroscopy using synchrotron radiation confirms the Auger analysis. Furthermore decomposition of the Pt4f 7/2 level permits quantification of the emission from the surface and interface atoms. Surface mobility of the Pt may also be inferred, coalescence of the surface layer occurs for coverages greater than 0.5 ML. XPD results confirm that the Pt grows with an fcc structure. An analysis of the anisotropies of the forward scattering peaks confirms the layer by layer growth model.

We have carried out a combined X-ray photoelectron diffraction (XPD) and low-energy electron diffraction (LEED) study of the interaction of oxygen with Ni(001) at ambient temperature from the c(2 × 2) structure up to the saturated oxide. Several structural conclusions are possible based on an R-factor comparison of an extensive series of azimuthal- and polar-O 1s XPD data to theoretical simulations based on a single-scattering cluster (SSC) model with spherical wave scattering. A new method for normalizing experimental and theoretical intensities for XPD R-factor analyses is also used. For the c(2 × 2) structure, we find that the oxygen sits in the fourfold hollows site, at a vertical distance (z) of approximately 0.75 A above the first Ni plane, in excellent agreement with the most recent LEED determination. There is also strong evidence from the XPD results that oxide nucleation occurs very early in the chemisorption region (much earlier than observable by LEED) and this effect could explain the proposals for in-plane bonding or pseudobridge bonding previously reported in the literature. The saturated oxide that forms at ambient temperatures is found from LEED and XPD to form a strained superlattice that is expanded by 1 6 with respect to the underlying Ni(001). We also find that the saturation oxide coverage is much larger than that previously reported in the literature of 2–3 monolayers (ML), and that it is in fact 4–5 ML. Other conclusions concerning the nature of the strain in the oxide are also possible, including a vertical expansion in lattice constant from the first to second plane of 0.1–0.2 A.

We have obtained azimuthal X-ray photoelectron diffraction (XPD) data with a high angular resolution of ± 1.5° for S2p emission from the well-defined surface structure of c(2 × 2)S on Ni(001). The relatively high position of the adsorbate with respect to the substrate makes this a stringent test case of the structural sensitivity of forward-scattering-dominated XPD. With this higher resolution, the data are nonetheless found to be sensitive to atomic structure, including in particular both the vertical height of S above Ni ( z ) and the first-to-second layer Ni interplanar spacing ( d 12 ). A single scattering cluster (SSC) theoretical analysis using R -factors to judge goodness of fit yields z = 1.39 ± 0.05 A and d 12 = 1.86 ± 0.05 A , in excellent agreement with other recent experimental and theoretical studies. This analysis also indicates that clusters of up to at least 25 A in radius (200–250 atoms) are needed to accurately describe all of the diffraction fine structure observed; thus, although XPD is primarily a short-range order probe, high-resolution data provides sensitivity to order that may go out as far as 10–15 neighbor shells. For takeoff angles with respect to the surface of less than about 10°, multiple scattering effects appear to become more important, as verified by fully converged multiple scattering cluster (MSC) calculations; however, for takeoff angles larger than 10°, these effects fall away rapidly, making a single-scattering analysis of such data still a useful approach. Finally, we have analyzed our experimental data and SSC simulations of it using recently suggested Fourier-transform holographic inversion methods. Although our data are too limited to permit fully accurate holographic imaging, features associated with the nearest neighbor S atoms in the adsorbate overlayer are seen in both experimental and theoretical images. In addition, the theoretical calculations indicate that the atomic images can be improved if: the solid angle of the hologram is limited so as to exclude the strong forward scattering features at low takeoff angles; effects due to non-constant scattering factor amplitudes and phases are corrected out using the scattered-wave-included Fourier-transform method of Saldin et al., and/or the hologram range is further limited so as to avoid the overlap of twin and real images. Several interesting directions for further study with such high-resolution data, SSC R -factor analyses, and holographic imaging, are thus suggested.

Angular distributions of Auger electrons and of photoelectrons emitted at high (>500 eV) and low (