Ion and Electron Momentum Distributions from Single and Double Ionization of Helium Induced by Compton Scattering.

We present the momentum distributions of the nucleus and of the electrons from double ionization of the helium atom by Compton scattering of photons with hν=40 keV. We find that the doubly charged ion momentum distribution is very close to the Compton profile of the nucleus in the ground state of the helium atom, and the momentum distribution of the singly charged ion to give a precise image of the electron Compton profile. To reproduce these results, nonrelativistic calculations require the use of highly correlated initial- and final-state wave functions.

Fourfold Differential Photoelectron Circular Dichroism.

We report on a joint experimental and theoretical study of photoelectron circular dichroism (PECD) in methyloxirane. By detecting O 1s photoelectrons in coincidence with fragment ions, we deduce the molecule's orientation and photoelectron emission direction in the laboratory frame. Thereby, we retrieve a fourfold differential PECD clearly beyond 50%. This strong chiral asymmetry is reproduced by ab initio electronic structure calculations. Providing such a pronounced contrast makes PECD of fixed-in-space chiral molecules an even more sensitive tool for chiral recognition in the gas phase.

Enantioselective fragmentation of an achiral molecule in a strong laser field.

Chirality is omnipresent in living nature. On the single molecule level, the response of a chiral species to a chiral probe depends on their respective handedness. A prominent example is the difference in the interaction of a chiral molecule with left or right circularly polarized light. In the present study, we show by Coulomb explosion imaging that circularly polarized light can also induce a chiral fragmentation of a planar and thus achiral molecule. The observed enantiomer strongly depends on the orientation of the molecule with respect to the light propagation direction and the helicity of the ionizing light. This finding might trigger new approaches to improve laser-driven enantioselective chemical synthesis.

Determination of Interatomic Potentials of He_{2}, Ne_{2}, Ar_{2}, and H_{2} by Wave Function Imaging.

We report on a direct method to measure the interatomic potential energy curve of diatomic systems. A cold target recoil ion momentum spectroscopy reaction microscope was used to measure the squares of the vibrational wave functions of H_{2}, He_{2}, Ne_{2}, and Ar_{2}. The Schrödinger equation relates the curvature of the wave function to the potential V(R) and therefore offers a simple but elegant way to extract the shape of the potential.

Absolute ion detection efficiencies of microchannel plates and funnel microchannel plates for multi-coincidence detection.

Modern momentum imaging techniques allow for the investigation of complex molecules in the gas phase by detection of several fragment ions in coincidence. For these studies, it is of great importance that the single-particle detection efficiency ε is as high as possible, as the overall efficiency scales with εn, i.e., the power of the number of detected particles. Here we present measured absolute detection efficiencies for protons of several micro-channel plates (MCPs), including efficiency enhanced "funnel MCPs." Furthermore, the relative detection efficiency for two-, three-, four-, and five-body fragmentation of CHBrClF has been examined. The "funnel" MCPs exhibit an efficiency of approximately 90%, gaining a factor of 24 (as compared to "normal" MCPs) in the case of a five-fold ion coincidence detection.

Erratum: Electron Localization in Dissociating H_{2}

This corrects the article DOI: 10.1103/PhysRevLett.116.043001.

Agreement of Experiment and Theory on the Single Ionization of Helium by Fast Proton Impact.

Even though the study of ion-atom collisions is a mature field of atomic physics, large discrepancies between experiment and theoretical calculations are still common. Here we present experimental results with high momentum resolution on the single ionization of helium induced by 1-MeV protons, and we compare these to theoretical calculations. The overall agreement is strikingly good, and even the first Born approximation yields good agreement between theory and experiment. This has been expected for several decades, but so far has not been accomplished. The influence of projectile coherence effects on the measured data is briefly discussed in terms of an ongoing dispute on the existence of nodal structures in the electron angular emission distributions.

Electron Localization in Dissociating H_{2}

We investigate the dissociation of H_{2}^{+} into a proton and a H^{0} after single ionization with photons of an energy close to the threshold. We find that the p^{+} and the H^{0} do not emerge symmetrically in the case of the H_{2}^{+} dissociating along the 1sσ_{g} ground state. Instead, a preference for the ejection of the p^{+} in the direction of the escaping photoelectron can be observed. This symmetry breaking is strongest for very small electron energies. Our experiment is consistent with a recent prediction by Serov and Kheifets [Phys. Rev. A 89, 031402 (2014)]. In their model, which treats the photoelectron classically, the symmetry breaking is induced by the retroaction of the long-range Coulomb potential onto the dissociating H_{2}^{+}.

Mechanical Thrombectomy Using the New ERIC Retrieval Device Is Feasible, Efficient, and Safe in Acute Ischemic Stroke: A Swiss Stroke Center Experience.

BACKGROUND AND PURPOSE: Intravenous thrombolysis and mechanical thrombectomy predominantly using stent retrievers have been shown to effectively restore cerebral blood flow and improve functional outcome in patients with acute ischemic stroke. We sought to determine the safety and feasibility of mechanical thrombectomy using the new ERIC retrieval device. MATERIALS AND METHODS: We identified 36 consecutive patients from our Stroke Center registry with acute ischemic stroke who were treated with the new ERIC retriever from September 2013 to December 2014. Patients with ischemic stroke meeting the following criteria were eligible: onset-to-treatment time of ≤4.5 hours or wake-up stroke (n = 10) with relevant CT perfusion mismatch, NIHSS score of ≥4, and proof of large-vessel occlusion in the anterior circulation on CT angiography. We assessed the baseline characteristics including age, sex, comorbidities, stroke severity, site of vessel occlusion, presence of tissue at risk, and treatment-related parameters such as onset-to-treatment time, recanalization grade, and outcome. RESULTS: The mean age was 70 ± 13 years, and the median NIHSS score on admission was 18 (interquartile range, 10-20). Seventeen of 36 patients were on platelet inhibitors or anticoagulants before endovascular treatment (47.2%); 20 patients received intravenous thrombolysis (55.5%). The ERIC was used as the sole retriever in 28 patients (77.8%) and as a rescue device in 8. Excellent recanalization was achieved in 30/36 patients (83.3%) with TICI 3 in 19/36 and 2b in 11/36, respectively. Median procedural time in these patients was 90 minutes (interquartile range, 58-133 minutes). No intraprocedural complications occurred. CONCLUSIONS: In this observational study, the new ERIC retrieval device was technically feasible, safe, and effective in acute ischemic stroke with large-vessel occlusion.

The challenge of the standardization of nursing specializations in Europe.

BACKGROUND: The evolution of health care is driving the need for specialist nursing knowledge. Specialist nurses have undertaken a formal training that focuses on a specific clinical area or population and are legitimated by a professional award or legal status. Specialist nurses are better able to provide the most specific and most appropriate care for both people and populations. AIM: This paper considers nursing's loose understanding of 'specialization' and the impact this has on those who seek employment outside their own nation but within the family of nations known as the European Union (EU). There is a lack of standardization for nursing specializations across the European Union that leads to lack of mobility across countries. SOURCES OF EVIDENCE: Reports were reviewed from within the European Union, including specialist nursing groups and regulatory nursing bodies. DISCUSSION: Nurse specialists can be regarded as operating at nursing's 'leading edge'; however, it is here that nursing lacks organization and common standards. This is readily apparent in a EU bound together by the principle of freedom of movement and common professional and academic standards. CONCLUSION: It is now time for European Union nurses to look beyond the common standards for pre-registration courses and to consider the development of common standards for specialist nursing. Historical attempts to achieve common standards for specialist nursing have largely been unsuccessful due to the diversity of approaches to nurse specialization. It is time now for this challenge to be re-addressed so that specialist nurses can more freely work throughout the European Union. IMPLICATIONS FOR NURSING POLICY: There is a pressing need for policy makers to define specialist nursing and to enable European Union-wide standards.

Brain-derived neurotrophic factor concentrations in tetraplegic athletes.

STUDY DESIGN: A prospective cohort with acute tetraplegia. OBJECTIVE: The purpose of this study was to investigate acute changes in serum brain-derived neurotrophic factor (BDNF) concentrations in tetraplegic spinal cord-injured (SCI) athletes during a typical training session of wheelchair rugby. SETTINGS: German Sport University Cologne, Cologne, Germany. METHODS: Eleven male SCI (AIS A and B) athletes completed a 90-min training session: The warm-up period included continuous pushing, submaximal increasing sprints and agility drills. The main training section comprised ball handling, passing drills, scrimmage activity and tactical practice. At the end of the training session, the athletes did moderate continuous pushing as a short cool-down. Venous blood samples were taken at rest before exercise, after the warm-up period and immediately following the first part of the main training section. Serum was pipetted after 30 min of blood sample resting and a subsequent centrifugation. BDNF concentrations were measured using an enzyme immunoassay ELISA kit. RESULTS: Heart rate (P < 0.01) and lactate (P = 0.04 and P < 0.01) concentration differed significantly in warm-up and main training part in comparison with basal values at rest. At rest, BDNF concentrations were 33.2 ± 21.6 ng ml(-1), after warm up 31.9 ± 18.9 ng ml(-1) and after the training session 29.9 ± 11 ng ml(-1), without significant differences (P > 0.05). CONCLUSIONS: A typical wheelchair rugby training session does not affect basal serum BDNF concentration in elite SCI athletes. In comparison with concentrations previously reported in healthy subjects, the current values at rest were slightly higher or rather at the upper limit.

Imaging the structure of the trimer systems (4)He3 and (3)He(4)He2.

Helium shows fascinating quantum phenomena unseen in any other element. In its liquid phase, it is the only known superfluid. The smallest aggregates of helium, the dimer (He2) and the trimer (He3) are, in their predicted structure, unique natural quantum objects. While one might intuitively expect the structure of (4)He3 to be an equilateral triangle, a manifold of predictions on its shape have yielded an ongoing dispute for more than 20 years. These predictions range from (4)He3 being mainly linear to being mainly an equilateral triangle. Here we show experimental images of the wave functions of (4)He3 and (3)He(4)He2 obtained by Coulomb explosion imaging of mass-selected clusters. We propose that (4)He3 is a structureless random cloud and that (3)He(4)He2 exists as a quantum halo state.

Intestinal alkaline phosphatase preserves the normal homeostasis of gut microbiota.

BACKGROUND AND AIMS: The intestinal microbiota plays a critical role in maintaining human health; however, the mechanisms governing the normal homeostatic number and composition of these microbes are largely unknown. Previously it was shown that intestinal alkaline phosphatase (IAP), a small intestinal brush border enzyme, functions as a gut mucosal defence factor limiting the translocation of gut bacteria to mesenteric lymph nodes. In this study the role of IAP in the preservation of the normal homeostasis of the gut microbiota was investigated. METHODS: Bacterial culture was performed in aerobic and anaerobic conditions to quantify the number of bacteria in the stools of wild-type (WT) and IAP knockout (IAP-KO) C57BL/6 mice. Terminal restriction fragment length polymorphism, phylogenetic analyses and quantitative real-time PCR of subphylum-specific bacterial 16S rRNA genes were used to determine the compositional profiles of microbiotas. Oral supplementation of calf IAP (cIAP) was used to determine its effects on the recovery of commensal gut microbiota after antibiotic treatment and also on the colonisation of pathogenic bacteria. RESULTS: IAP-KO mice had dramatically fewer and also different types of aerobic and anaerobic microbes in their stools compared with WT mice. Oral supplementation of IAP favoured the growth of commensal bacteria, enhanced restoration of gut microbiota lost due to antibiotic treatment and inhibited the growth of a pathogenic bacterium (Salmonella typhimurium). CONCLUSIONS: IAP is involved in the maintenance of normal gut microbial homeostasis and may have therapeutic potential against dysbiosis and pathogenic infections.

Infection with Mycobacterium avium subspecies avium in a 10 year old Freiberger mare.

In this case report a 10 year old Freiberger mare with a Mycobacterium avium subsp. avium infection is presented. This infection leads to a tuberculosis like disease with granulomatous alterations particularly of the intestines and lungs and is only sporadically reported in horses of Central Europe. Diarrhoea, mastitis and neck stiffness as well as dyspnoea and chronic cough are more specific symptoms of the infection, while weight loss, weakness and lethargy are nonspecific signs. As these clinical signs can occur in many other diseases, the diagnosis of mycobacterial infection is difficult and consists of rectum or distal colon biopsies and staining for acid-fast bacilli and bacteriological culture of granulomatous lesions. Classification of M. avium subsp. avium was achieved by PCR-RFLP. Even though an infection with Mycobacterium avium subsp. avium is rare, it belongs to the differential diagnosis of granulomatous diseases.

Modeling of the modulation by buffers of Ca2+ release through clusters of IP3 receptors.

Intracellular Ca(2+) release is a versatile second messenger system. It is modeled here by reaction-diffusion equations for the free Ca(2+) and Ca(2+) buffers, with spatially discrete clusters of stochastic IP(3) receptor channels (IP(3)Rs) controlling the release of Ca(2+) from the endoplasmic reticulum. IP(3)Rs are activated by a small rise of the cytosolic Ca(2+) concentration and inhibited by large concentrations. Buffering of cytosolic Ca(2+) shapes global Ca(2+) transients. Here we use a model to investigate the effect of buffers with slow and fast reaction rates on single release spikes. We find that, depending on their diffusion coefficient, fast buffers can either decouple clusters or delay inhibition. Slow buffers have little effect on Ca(2+) release, but affect the time course of the signals from the fluorescent Ca(2+) indicator mainly by competing for Ca(2+). At low [IP(3)], fast buffers suppress fluorescence signals, slow buffers increase the contrast between bulk signals and signals at open clusters, and large concentrations of buffers, either fast or slow, decouple clusters.

Molecular and immunological characterization of Asp f 34, a novel major cell wall allergen of Aspergillus fumigatus.

BACKGROUND: Although fungal spores have been recognized as triggers of respiratory allergy and asthma, only two allergenic fungal cell wall components have so far been described. METHODS: Eighty-one sequences derived from an Aspergillus fumigatus cDNA library encoding putative allergens were examined for the presence of cell wall components. A new allergen (Asp f 34) was evaluated by Western blots, enzyme-linked immunosorbent assay (ELISA), peripheral blood mononuclear cell (PBMC) proliferation assays, and skin prick test (SPT). RESULTS: The cDNA encoding Asp f 34 contained an open reading frame predicting a protein of 185 amino acids with a molecular weight of 19.38 kDa, showing sequence homology to phiA, an essential protein for the formation of conidia in the genus Aspergillus. The recombinant Asp f 34 was binding IgE from sensitized individuals in Western blots. An ELISA survey showed that 94% of the ABPA and 46% of the A. fumigatus-sensitized individuals tested had Asp f 34-specific serum IgE. Asp f 34 induced allergen-specific proliferation exclusively of PBMCs from patients sensitized to the allergen. Eight patients with anti-Asp f 34 serum IgE tested reacted positively in SPT, whereas four A. fumigatus-sensitized individuals without Asp f 34-specific IgE and eight healthy controls scored negatively. CONCLUSIONS: A cell wall protein of the phialides of A. fumigatus was identified as a major allergen. Asp f 34 belongs to the Aspergillus-specific proteins of the phiA family and has relevant potential for a specific diagnosis of Aspergillus sensitization.

An unusual cause of traumatic reticulitis/reticuloperitonitis in a herd of Swiss dairy cows nearby an airport.

This report describes the findings in five cows from one dairy herd, in which all 31 cows were slaughtered or euthanised because of traumatic reticuloperitonitis. All the cows had numerous thin sharp pieces of metal attached to a magnet in the reticulum, giving the magnet a hedgehog-like appearance. Investigation revealed that the cattle had eaten forage harvested from a field immediately adjacent to an airport. The snow was cleared from the airport runways with a machine that had a wire-bristle brush attachment. Mechanical wear resulted in numerous wire bristles breaking and these were blown with the snow onto the field in question. The wire then became accidentally incorporated into the hay and grass silage at harvest the next summer and was ingested by the cattle in the fall and winter. To prevent further cases, approximately 200 tonnes of hay and grass silage contaminated with wire were discarded and 30 hectares of the 50-hectare field were cultivated and re-sown. The wire-bristles of the snow plow were replaced with plastic bristles. The cost of this and the livestock loss was several hundred thousand Swiss Francs.

Auto- and cross-reactivity to thioredoxin allergens in allergic bronchopulmonary aspergillosis.

BACKGROUND: Thioredoxins are cross-reactive allergens involved in the pathogenesis of atopic eczema and asthma. Cross-reactivity to human thioredoxin can contribute to the exacerbation of severe atopic diseases. METHODS: Human thioredoxin, Asp f28 and Asp f29, two thioredoxins of Aspergillus fumigatus, and thioredoxin of Malassezia sympodialis were cloned and produced as recombinant proteins. Allergenicity and cross-reactivity to thioredoxins in allergic bronchopulmonary aspergillosis patients were assessed by enzyme-linked immunosorbent assay (ELISA), inhibition ELISA, immunoblot analysis, proliferation assays and skin tests. Molecular homology modelling was used to identify conserved, surface-exposed amino acids potentially involved in immunoglobulin E (IgE)-binding. RESULTS: All thioredoxins, including the human enzyme, bind IgE from patients with allergic bronchopulmonary aspergillosis and induce allergen-specific proliferation in peripheral blood mononuclear cells and positive skin reactions in thioredoxin-sensitized patients. Inhibition experiments showed that the thioredoxins are cross-reactive indicating humoral immune responses based on molecular mimicry. To identify structural surface elements involved in cross-reactivity, the three-dimensional structures were modelled based on solved thioredoxin structures. Analysis of the molecular surfaces combined with sequence alignments allowed identification of conserved solvent exposed amino acids distantly located in the linear sequences which cluster to patches of continuous surface areas. The size of the surface areas conserved between human and fungal thioredoxins correlates well with the inhibitory potential of the molecules in inhibition ELISA indicating that the shared amino acids are involved in IgE-binding. CONCLUSIONS: Conserved, solvent exposed residues shared between different thioredoxins cluster to continuous surface regions potentially forming cross-reactive conformational B-cell epitopes responsible for IgE-mediated cross-reactivity and autoreactivity.

Compact Er:Yb:glass-laser-based supercontinuum source for high-resolution optical coherence tomography.

We present a low coherence light source by direct super-continuum generation from a diode-pumped, passively modelocked Er:Yb:glass-laser, which generates 198 fs transform-limited pulses with an average power of 100 mW at a repetition rate of 75 MHz. The pulse train is launched into a dispersion optimized highly nonlinear fiber for spectral broadening. The optical bandwidth spans from 1150 nm to 2400 nm, which is more than one octave. The potential for ultrahigh-resolution optical coherence tomography (OCT) is demonstrated by coherence measurements supporting an axial resolution of 3.5 microm in air.