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Objective Early diagnosis of atrial fibrillation (AFib) is a priority for stroke prevention. We sought to test four commercial pulse detection systems (CPDSs) for ability to distinguish AFib from normal sinus rhythm using a published algorithm (Zhou et al., PLoS One 2015;10:e0136544), compared with visual diagnosis by electrocardiogram inspection. Methods BAYathlon was a prospective, non-interventional, single-centre study. Adult cardiology patients with documented AFib or sinus rhythm who were due to have a routine 5-min electrocardiogram were randomized to undergo a parallel 5-min pulse assessment with a Polar V800, eMotion Faros 360, TomTom heart rate monitor, or Adidas miCoach Smart Run. Results 144 patients (73 with AFib, 71 with sinus rhythm (based on electrocardiograms); median age: 73 years; 53.5% male) were analysed. Algorithm sensitivities (primary endpoint) and specificities for AFib when applied to CPDS recordings were 93.3% and 94.1% with the Polar V800, 90.0% and 84.2% with the eMotion Faros 360, and 0% and 100% with the other CPDSs (analysis period: 127 heart rate signals + 2 min). When applied to routine electrocardiograms, the algorithm correctly detected AFib in 71/73 patients. Different analysis periods (127 heart rate signals +1 or 3 min) only slightly changed the sensitivities with the Polar V800 and eMotion Faros 360 and had no effect on the sensitivities with the other CPDSs. Conclusion AFib screening using the applied algorithm is feasible with the Polar V800 and eMotion Faros 360 (which provide RR interval data) but not with the other CPDSs (which provide pre-processed heart rate time series). ClinicalTrials.gov identifier: NCT02875106

Background Pulmonary arterial hypertension restricts the ability of patients to perform routine physical activities. As part of pulmonary arterial hypertension treatment, inhaled iloprost can be administered via a nebulizer that tracks inhalation behavior. Pulmonary arterial hypertension treatment is guided by intermittent clinical measurements, such as 6-minute walk distance, assessed during regular physician visits. Continuous digital monitoring of physical activity may facilitate more complete assessment of the impact of pulmonary arterial hypertension on daily life. Physical activity tracking with a wearable has not yet been assessed with simultaneous tracking of pulmonary arterial hypertension medication intake. Objective We aimed to digitally track the physical parameters of patients with pulmonary arterial hypertension who were starting treatment with iloprost using a Breelib nebulizer. The primary objective was to investigate correlations between changes in digital physical activity measures and changes in traditional clinical measures and health-related quality of life over 3 months. Secondary objectives were to evaluate inhalation behavior, adverse events, and changes in heart rate and sleep quality. Methods We conducted a prospective, multicenter observational study of adults with pulmonary arterial hypertension in World Health Organization functional class III who were adding inhaled iloprost to existing pulmonary arterial hypertension therapy. Daily distance walked, step count, number of standing-up events, heart rate, and 6-minute walk distance were digitally captured using smartwatch (Apple Watch Series 2) and smartphone (iPhone 6S) apps during a 3-month observation period (which began when iloprost treatment began). Before and at the end of the observation period (within 2 weeks), we also evaluated 6-minute walk distance, Borg dyspnea, functional class, B-type natriuretic peptide (or N-terminal pro–B-type natriuretic peptide) levels, health-related quality of life (EQ-5D questionnaire), and sleep quality (Pittsburgh Sleep Quality Index). Results Of 31 patients, 18 were included in the full analysis (observation period: median 91.5 days, IQR 88.0 to 92.0). Changes from baseline in traditional and digital 6-minute walk distance were moderately correlated (r=0.57). Physical activity (daily distance walked: median 0.4 km, IQR –0.2 to 1.9; daily step count: median 591, IQR −509 to 2413) and clinical measures (traditional 6-minute walk distance: median 26 m, IQR 0 to 40) changed concordantly from baseline to the end of the observation period. Health-related quality of life showed little change. Total sleep score and resting heart rate slightly decreased. Distance walked and step count showed short-term increases after each iloprost inhalation. No new safety signals were identified (safety analysis set: n=30). Conclusions Our results suggest that despite challenges, parallel monitoring of physical activity, heart rate, and iloprost inhalation is feasible in patients with pulmonary arterial hypertension and may complement traditional measures in guiding treatment; however, the sample size of this study limits generalizability. Trial Registration ClinicalTrials.gov NCT03293407; https://clinicaltrials.gov/ct2/show/NCT03293407 International Registered Report Identifier (IRRID) RR2-10.2196/12144

BACKGROUND Pulmonary arterial hypertension restricts the ability of patients to perform routine physical activities. As part of pulmonary arterial hypertension treatment, inhaled iloprost can be administered via a nebulizer that tracks inhalation behavior. Pulmonary arterial hypertension treatment is guided by intermittent clinical measurements, such as 6-minute walk distance, assessed during regular physician visits. Continuous digital monitoring of physical activity may facilitate more complete assessment of the impact of pulmonary arterial hypertension on daily life. Physical activity tracking with a wearable has not yet been assessed with simultaneous tracking of pulmonary arterial hypertension medication intake. OBJECTIVE We aimed to digitally track the physical parameters of patients with pulmonary arterial hypertension who were starting treatment with iloprost using a Breelib nebulizer. The primary objective was to investigate correlations between changes in digital physical activity measures and changes in traditional clinical measures and health-related quality of life over 3 months. Secondary objectives were to evaluate inhalation behavior, adverse events, and changes in heart rate and sleep quality. METHODS We conducted a prospective, multicenter observational study of adults with pulmonary arterial hypertension in World Health Organization functional class III who were adding inhaled iloprost to existing pulmonary arterial hypertension therapy. Daily distance walked, step count, number of standing-up events, heart rate, and 6-minute walk distance were digitally captured using smartwatch (Apple Watch Series 2) and smartphone (iPhone 6S) apps during a 3-month observation period (which began when iloprost treatment began). Before and at the end of the observation period (within 2 weeks), we also evaluated 6-minute walk distance, Borg dyspnea, functional class, B-type natriuretic peptide (or N-terminal pro–B-type natriuretic peptide) levels, health-related quality of life (EQ-5D questionnaire), and sleep quality (Pittsburgh Sleep Quality Index). RESULTS Of 31 patients, 18 were included in the full analysis (observation period: median 91.5 days, IQR 88.0 to 92.0). Changes from baseline in traditional and digital 6-minute walk distance were moderately correlated (r=0.57). Physical activity (daily distance walked: median 0.4 km, IQR –0.2 to 1.9; daily step count: median 591, IQR −509 to 2413) and clinical measures (traditional 6-minute walk distance: median 26 m, IQR 0 to 40) changed concordantly from baseline to the end of the observation period. Health-related quality of life showed little change. Total sleep score and resting heart rate slightly decreased. Distance walked and step count showed short-term increases after each iloprost inhalation. No new safety signals were identified (safety analysis set: n=30). CONCLUSIONS Our results suggest that despite challenges, parallel monitoring of physical activity, heart rate, and iloprost inhalation is feasible in patients with pulmonary arterial hypertension and may complement traditional measures in guiding treatment; however, the sample size of this study limits generalizability. CLINICALTRIAL ClinicalTrials.gov NCT03293407; https://clinicaltrials.gov/ct2/show/NCT03293407 INTERNATIONAL REGISTERED REPORT RR2-10.2196/12144

The daily life on earth relies on the undisturbed services of satellites and space missions. With the growing amount of space debris particles the space-based infrastructure is increasingly endangered. To protect satellites and space missions it is mandatory to identify, track and monitor space debris objects with highly sensitive radar sensors. To support the German Space Situational Awareness Center, the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR) was commissioned by the DLR Space Administration in 2015 to design a high performance L-band phased-array radar to observe the low-earth orbit: GESTRA (German Experimental Space Surveillance and Tracking Radar). The long-term aim of GESTRA is to build up a catalog with orbital data for objects located at altitudes of less than 3000 km. GESTRA will provide valuable data sets for the global space situational awareness efforts.

Space debris is an ongoing and growing problem for space-based infrastructure. The rising population of man-made debris particles has the potential to destroy operational satellites and spacecrafts. In order to avoid the risk of collisions it is of cardinal importance to locate, track and identify artificial objects orbiting the earth. Therefore, it is necessary to develop technologies related to surveillance radars. On behalf of the Federal Government the German Space Administration (DLR) commissioned the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR) in 2015 to develop and design a new phased-array radar to monitor the low-earth orbit. This so-called German Experimental Surveillance and Tracking Radar (GESTRA) will support the German Space Situational Awareness Center to generate a catalogue of orbital data for objects at altitudes of less than 3000 km. Incorporating state of the art technology, the concept of the new GESTRA radar system will provide high quality data sets.

The Cape horse mackerel stock off Namibia is assessed using a fleet-disaggregated age-structured production model including historical International Commission for the Southeast Atlantic Fisheries (ICSEAF) and current data. Data from acoustic biomass surveys, on commercial catch per unit effort and on commercial catch-at-age, were used to estimate current stock status over a range of model specifications. A management tool, the so-called management monitor graph, was introduced in order to track past management relative to stock status. Target, limit and precautionary reference points, decision rules and harvesting strategies, according to which the stock should be managed, are described and tested. The target reference point was set at maximum sustainable yield (MSY), the precautionary reference point at 80% of MSY and the limit reference point at 30% of MSY. Owing to some inconsistencies in the dataseries, evaluation of the current state of the resource is challenging, but estimates are that the resourc...

We show how the Aw–Rascle model, a hyperbolic system of PDEs modeling traffic flow, can be derived from a simplified Fokker–Planck type kinetic equation.

The effects on surface morphology, crystal quality, and growth rate of undoped AlN layers grown on c -plane sapphire substrates due to the changes in growth parameters, such as V–III ratio, N 2 – H 2 ratio, and growth temperature in LP-MOVPE are studied here. The optimized growth process resulted in an almost flat surface morphology with a significantly reduced number of hexagonal pits ( 3 × 10 7 cm - 2 ) and good crystalline quality having a rms value of roughness of 0.4 nm measured by atomic force microscopy and a high resolution X-ray diffraction (HRXRD) FWHM value for (0 0 0 2) reflection of 200 arcsecs. The threading dislocation density of the AlN layer is estimated approx. 10 9 cm - 2 from cross-sectional transmission electron microscopy (TEM) measurements. Additionally, these optimized samples show a strong donor-bound exciton luminescence signal with a FWHM of 20 meV. Furthermore, small period AlN/GaN superlattice structures with excellent uniformity were grown, as proven by our HRXRD and TEM studies.

Transmission electron microscopy was used to characterize dislocations in n-ZnO and n-GaN epitaxial layers grown on Al2O3(0 0 0 1) substrates. Threading segments of misfit dislocations with screw, edge and mixed character are observed with varying fractions depending on the epitaxial growth procedure. The electrical activity of single dislocations is studied by off-axis electron holography in a transmission electron microscope. An electrostatic potential in the vicinity of the dislocations is detected for ZnO and GaN, which clearly demonstrates that charges are present close to the dislocation core. Applying Read′s model for the potential of a screened line charge, high charge densities of approximately 2 elementary charges per nm dislocation length are derived.

In the last two decades, diluted magnetic semiconductors have attracted great attention as promising materials for spintronics applications. [K. Sato, H. Katyama-Yoshida, Jpn. J. Phys., Part 2 39 (2000) L555] theoretically predicted that ZnO doped with V, Cr, Fe, Co, and Ni can be ferromagnetic. This has been recently confirmed experimentally for vanadium doped ZnO films which were grown on sapphire substrates, using laser deposition technique [H. Saeki, H.N. Tabata, T. Kawai, Solid State Commun. 120 (2001) 439]. In the present work, high-dose vanadium implantation was used to produce Zn 1− x V x O ( x ∼ 0.10) thin film structures (250 nm thick) that had been epitaxially grown on sapphire substrates. Implantation with the dose 2 × 10 16 cm −2 was performed to reach a maximum vanadium concentration of 10 at%. To avoid ZnO film amorphization due to radiation damage accumulation [S.O. Kucheyev, J.S. Williams, C. Jagadish, J. Zou, C. Evans, A.J. Nelson, A.V. Hamza, Phys. Rev. B 67 (2003) 094115], all implants were done at elevated temperatures 300 and 400 °C and ion current density 10 μA/cm 2 . X-ray diffraction, SIMS and photoluminescence techniques were exploited to study the implanted samples. No luminescence was observed in the implanted samples after implantation procedures. However, annealing at 800 °C for 30 min gave rise to ZnO crystal structure improvement. This implies that healing of implantation induced defects is possible even after heavy-ion bombardment. As a result, the photoluminescence peak at 3.359 eV related to the donorbound exiton was detected.

We report on the studies of linearly polarized photoluminescence (PL) in a (0001) oriented ZnO epitaxial film, grown by metal organic chemical vapor deposition on a GaN template. The emission of mixed longitudinal-transverse exciton polariton modes was observed up to 130 K that evidences polaritonic nature of the excitonic spectrum up to this elevated temperature.

Background The decreasing number of organ donors in Germany remains a major issue in transplantation medicine. The aim of this study was to estimate the organ donor potential at German maximum care hospitals. Methods To critically review potential in comparison with organ donation rates in 2010. We separated Maximum care hospitals into university institutions (A-level) and centers with a neurosurgical unit (B-level) based upon the size of hospital as indicated by the total number of beds. To estimate the number of possible organ donors, we adopted the American model previously published by Sheehy et al: the potential was 0.015 organ donors/bed/year for hospitals with more than 350 beds. Results In 2010 overall in Germany there were 1296 organ donations resulting in 4205 transplanted organs. University hospitals realized 397 organ donations namely 0.008 organ donors/bed/year (57% of calculated organ donor potential), whereas B-level hospitals accounted for 555 of organ donors with a rate of 0.007 organ donors/bed/year (48% of calculated organ donor potential). Large variations in realizing organ donations occurred among single hospitals. Conclusion Our results indicated a substantial potential to increase organ donation rates in German maximum care hospitals. These hospitals (n = 145) are responsible for 73% (non-maximum care hospital n = 1195) of the absolute organ donor pool. Further studies are needed to evaluate possibilities to address the organ shortage particularly with regard to donor detection in intensive care units and also the refusal rate by families.

In this contribution we analyse the structural and optical properties of ZnO as well as ZnMgO nanopillars grown catalyst-free by metalorganic vapour-phase epitaxy. The nanostructures were grown directly onto different substrate materials with various orientations. The nanopillars deposited on a-plane sapphire show the best vertical c-axis alignment and have a typical diameter of about 50 nm and a height of several micrometres, depending on growth time. We achieved well ordered, almost completely c-axis oriented pillars, as confirmed by scanning electron microscopy and high resolution x-ray diffraction. Photoluminescence measurements revealed very narrow donor-bound exciton emission lines with half widths as small as 0.5 meV. In order to investigate the possibility of a combination of band gap engineering and nanopillar growth, ZnMgO nanopillars were also grown. The Mg incorporation was confirmed by photoluminescence measurements and a blue shift of the band gap of up to 170 meV could be achieved for the nanopillars with the highest Mg concentration.

Due to its band gap of 3.3 eV and exciton binding energy of 60 meV, ZnO is a very interesting candidate for UV optoelectronics. Beyond that, the incorporation of magnetic impurities allows fabrication of semimagnetic semiconductors, which are potentially ferromagnetic at room temperature. Here, we report on our results of the MOVPE growth of ZnO thins films grown on various substrates using i-PrOH and t-BuOH as oxygen precursors. Despite the fact that the lattice constant of ZnO is larger than that of GaN, ZnO films are often tensile strained. One reason for that is the difference in thermal expansion of ZnO relative to the substrate material. The low-temperature photoluminescence of ZnO layers is dominated by donor-bound excitons, with a half width below 1 meV at low temperatures for optimized growth parameters. By a thorough analysis of the strain state by reciprocal space mapping the Poisson number of ZnO is derived. The shift of the excitonic features (A- and B-excitons) as function of strain has been measured.

Gallium and nitrogen ions have been implanted into ZnO crystals and metal organic vapor phase epitaxy grown ZnO layers. Postimplantation annealing behavior in the temperature range between 200 and 900 °C has been studied by means of Raman scattering and low-temperature photoluminescence. The temperature for healing of the implantation-induced defects was found to be 800 °C. Implanted gallium acts as donor with a donor binding energy ED of 53 meV, thus allowing the control of n-type doping in ZnO. From photoluminescence measurements of the donor-acceptor pair transition of a series of nitrogen-implanted ZnO samples we estimate the binding energy EA of the nitrogen acceptor between 163 and 196 meV. Electrical characterization of nitrogen-implanted samples shows a behavior ranging from low n-type to highly compensated. But no unambiguous and reproducible type conversion could be achieved.

X-ray specular reflectivities of GaAs samples passivated with a thin film of (3-mercaptopropyl)-trimethoxysilane (MPT) have been studied using bending-magnet synchrotron radiation. Various preparation procedures covering etching the GaAs, MPT deposition and its baking have been investigated. An oxide film is always observed between the GaAs and MPT films. The microstructural parameters, such as film thickness, density and interfacial roughness (including the external surface), have been determined from appropriate modeling of the reflectivity. The surface roughness has been compared with a direct measurement using tapping-mode atomic force microscopy. The results are discussed with reference to the potential applications of GaAs as a biosensor.

The II–VI compound semiconductor ZnO is already widely used for various applications such as UV resistive coatings, gas sensors and surface acoustic wave devices. Recently, the optoelectronic properties of ZnO are attracting increasing interest, which has been initiated by first reports on p-type doping. ZnO appears especially favorable for such applications because of its large exciton binding energy of about 60 meV, its low-power thresholds for optical pumping at room temperature and the availability of bulk ZnO substrates. Here, we report on the metal-organic vapor phase epitaxy growth of ZnO layers using diethylzinc as the zinc source and iso-propanol or tertiary-butanol as the oxygen precursors. The choice of an appropriate oxygen precursor is of great importance to minimize parasitic prereactions in the gas phase, that have a negative influence on layer quality. Epitaxial growth is conducted in a water-cooled, RF-heated horizontal quartz glass reactor. Growth rates up to 2.6 μm have been accomplished. The influence of the growth parameters as substrate temperature, reactor pressure, gas flow rates, and especially the impact of the II/VI-ratio on growth rates and quality of the epitaxial material will be discussed.

In this paper we report on the metal-organic chemical vapour deposition of ZnO layers. We focus on heteroepitaxial growth on c-plane Al 2 O 3 and the influence of the VI/II ratio during growth on the properties of the layers. The layer quality has been investigated by HRXRD, PL and reflectivity measurements. Under optimized growth conditions the photoluminescence is dominated by strong near band edge emission lines with half widths below 4 meV and the excitonic signals are clearly visible in reflectivity measurements. Hall effect measurements indicate an n-type background doping in the 10 17 cm -3 range, and mobilities of more than 100 cm 2 /Vs can be reached. Moreover, a post-growth annealing step is found to improve the quality of the layers grown under suboptimal conditions. The problem of strain will be addressed and a tensile strain can be confirmed in the heteroepitaxial ZnO layers.

Dry-etching of laser facets is commonly used for (InAl)GaN/sapphire-based structures since the epitaxial planes of the nitride layers are rotated with respect to the substrate planes making cleaving impractical. To achieve steep and smooth facets by chemically assisted ion beam etching, a 3-layer resist system is developed for patterning. Characterization by scanning electron microscopy and atomic force microscopy shows facets with root-mean-square roughnesses of 7 nm and inclination angles of 2–4°. Optically pumped lasers yield low threshold excitation densities for fully doped separate confinement heterostructure lasers.

In this article, multiple-step rapid thermal annealing (RTA) processes for the activation of Mg doped GaN are compared with conventional single-step RTA processes. The investigated multiple-step processes consist of a low temperature annealing step at temperatures between 350 C and 700 C with dwell times up to 5 min and a short time high temperature step. With optimized process parameters, and multiple-step processes, we achieved p-type free carrier concentrations up to 1-2 × 10 18 cm 3 . The best achieved conductivity, so far, lies at 1.2Ω 1 cm 1 This is a 50% improvement compared to conventional single-step process at 800°C, 10 min.

It is shown that bulk MOVPE-grown GaN can exhibit dramatically increased near-band-edge and below-bandgap emission after argon plasma etching. The temperature dependence of the near-band-edge emission shows that donor-bound excitons are the dominant species in Ar-etched samples while free excitons dominate spectra from unetched samples. Under UV illumination and at low temperatures metastable behaviour is apparent from the defect-related blue and yellow luminescence bands. The clear linkage between the yellow and blue emission bands indicates that any microscopic model of the defect(s) associated with the yellow luminescence must also be able to explain the blue luminescence. At room temperature, UV illumination over a period of time enhances the yellow emission by a factor of 20 and it is shown that this effect can be employed for room-temperature optical data storage and retrieval.

The optical properties of reactive ion-etched GaN have been investigated. Under UV illumination etched samples exhibit a transfer of intensity from a blue luminescence band to a yellow luminescence band. The metastable defects introduced by reactive ion etching may be relevant to possible optical memory applications of GaN.

The frequencies and dampings of the zone-center optical phonons E2 and A1(LO) in wurtzite-type GaN and AlN layers have been measured by Raman spectroscopy in the temperature range from 85 to 760 K. The GaN layer was grown by metalorganic vapor phase epitaxy and the AlN layer by molecular beam epitaxy both on sapphire substrate. The experimentally obtained frequencies and dampings are modeled by a theory taking into account the thermal expansion of the lattice, a symmetric decay of the optical phonons into two and three phonons of lower energy, and the strain in the layers induced by the different thermal expansion coefficients of layer and substrate. The results were used to determine the local temperature of a GaN pn diode in dependence on the applied voltage.

Homoepitaxial GaN layers grown by MOVPE on a pre-treated GaN single crystal are almost strain-free, have very low defect densities and low impurity levels. These layers show strong, extraordinarily sharp photoluminescence spectra. Especially, the donor-(D0, X) and acceptor-(A0, X) bound excitons at ≈3.471 eV and 3.465 eV, respectively, exhibit line widths of ≈100 μeV, and ample fine structures can be resolved. For the (D0, X), complicated spectra are observed in the spectral region of two-electron-transitions and in the excited bound exciton state. For both (D0, X) and (A0, X), the respective bound exciton states belonging to all three valence bands are found. By variation of the sample temperature and excitation density, we separate the spectral features contributed by different impurities and reassign several lines in the band gap region.

High quality homoepitaxial GaN layers grown by MOVPE on a pre-treated GaN single crystal allow the measurement of photoluminescence (PL) and reflectance (RF) spectra with drastically improved resolution and emission intensity. For all three valence bands, at least the lowest two exciton states clearly show up in our RF spectra. A full fit procedure based on an exciton-polariton model including spatial dispersion allows a very precise determination of the exciton energies for ideal, unstrained material. In PL, the donor (D0, X) and acceptor (A0, X) bound excitons exhibit linewidths of ≈100 μeV and show an ample fine structure including two-electron transitions in the case of (D0, X).

The characteristics of Cl"2?Ar chemically-assisted ion-beam etching processes for GaN and GaAs are reported. The etch rate and anisotropy have been investigated varying ion energy, tilt angle, substrate temperature, and Cl"2 flow. Vertical and smooth sidewalls, which fulfill the requirements on laser facets, have been demonstrated in GaAs and GaN.

InxGa1−xN and AlxGa1−xN layers were grown by metalorganic chemical vapour deposition (MOCVD) on highly conductive single crystals of GaN. The samples were then examined using X-ray diffraction and photoluminescence. It was found that there is a substantial difference in properties between the layers grown on the N-face (00.{ 1 }), chemically active, and Ga-face (00.1), chemically inert, sides. The latter layers had smaller free-electron concentration, better crystallographic quality and different chemical compositions. All the examined layers were fully strained, even for 1.1% lattice mismatch between the GaN substrate and about 0.1 μm thick In0.11Ga0.88N layer. The half-widths of the photoluminesce (PL) dominant peaks correspond to the compositional gradients observed in X-ray diffraction. The positions of the PL peaks agree with the X-ray data if bowing parameters of 3.2 eV for InGaN layers and 0.25 eV for AlGaN layers were used.

Methylmercury (MeHg) is recognized as a significant environmental hazard, particularly to the development of the nervous system. Studies on the mechanism of MeHg-induced toxicity reveal that inhibition of cell cycle progression may be one way by which MeHg interferes with normal development. In this study, we utilized primary rodent embryonic neuronal cell (CNS) and limb bud (LB) cultures to determine the mRNA expression level of two genes involved in cell cycle arrest, Gadd45 and Gadd153, both during cellular differentiation and in response to MeHg exposure. A differential expression pattern of Gadd45 and Gadd153 was observed during CNS and LB differentiation in culture. However, both CNS and LB cells responded to MeHg exposure with a concentration-dependent increase in Gadd45 and Gadd153 mRNA. Previous studies have shown that MeHg exposure (2 μ m ) of CNS cells for 24 hr causes a fourfold decrease in the number of cells passing through the cell cycle. The present study shows that at the same exposure concentration, a five- to eightfold increase in Gadd45 mRNA levels and a two- to fourfold increase of Gadd153 was observed. Induction of Gadd45 was also noted in adult female mice chronically exposed to 10 ppm MeHg, a dose that caused developmental toxicity in vivo. Based on the known involvement of the Gadd genes in cell cycle arrest, activation of these genes could be one mechanism by which MeHg interferes with the cell cycle in adult and developing organisms.

Human-human interactions are of central relevance for the success in professional and occupational environments, which also substantially influence quality of life. This is especially true in the case of individuals with high-functioning autism (HFA), who experience deficits in social cognition that often lead to social exclusion and unemployment. Despite good education and high motivation, individuals with HFA do not reach employment rates that are substantially higher than 50 %. This is an alarmingly high rate of unemployment considering that the United Nations have recently emphasized the inclusion of handicapped persons as a mandatory human right. To date, the specific needs of autistic persons with respect to their working environment are largely unexplored. It remains moreover an open question how support systems and activities, including newly developed communication devices for professional environments of individuals with HFA, should look like. The German health and social care systems are not adequately prepared for the proper support of this population. This leads us to suggest that supported employment programs should be developed for adults with HFA that specifically address their needs and requirements. Such programs should comprise (1) the adequate assessment of HFA, including a neuropsychological profile and an individual matching of persons' preferences with requirements of the working place, (2) on-the-job coaching activities that include systematic communication and interaction training, and (3) instruction of non-autistic peers, including colleagues and supervisors, about weaknesses and strengths of HFA.

We have investigated the properties of ZnMgO epilayers and ZnO–ZnMgO quantum well structures grown by metalorganic vapor-phase epitaxy. A well-controlled incorporation of magnesium, x⩽0.10, could be confirmed resulting in a blueshift of the photoluminescence emission wavelength of the Zn1−xMgxO layers up to 200meV. Using ZnMgO as barrier material, ZnO–ZnMgO quantum well structures with different well widths have then been fabricated. The confinement effect in the ZnO quantum wells leads to the expected increase of the corresponding quantum well emission energy with decreasing well width. A comparison to calculations also suggests a further enhancement of the exciton binding energy in the quantum wells of up to 90meV.

Prostaglandin E2 has been reported both to stimulate glycogen-phosphorylase activity (glycogenolytic effect) and to inhibit the glucagon-stimulated glycogen-phosphorylase activity (antiglycogenolytic effect) in rat hepatocytes. It was the purpose of this study to resolve this apparent contradiction and to characterize the signalling pathways and receptor subtypes involved in the opposing prostaglandin E2 actions. Prostaglandin E2 (10 μM) increased glucose output, glycogen-phosphorylase activity and inositol trisphosphate formation in hepatocyte cell culture and/or suspension. In the same systems, prostaglandin E2 decreased the glucagon-stimulated (1 nM) glycogen-phosphorylase activity and cAMP formation. The signalling pathway leading to the glycogenolytic effect of PGE2 was interrupted by incubation of the hepatocytes with 4β-phorbol 12-myristate 13-acetate (100 nM) for 10 min, while the antiglycogenolytic effect of prostaglandin E2 was not attenuated. The signalling pathway leading to the antiglycogenolytic effect of prostaglandin E2 was interrupted by an incubation of cultured hepatocytes with pertussis toxin (100 ng/ml) for 18 h, whereas the glycogenolytic effect of prostaglandin E2 was enhanced. The EP1/EP3 prostaglandin-E2-receptor-specific prostaglandin E2 analogue Sulproston had a stronger glycogenolytic potency than the EP3 prostaglandin-E2-receptor-specific prostaglandin E2 analogue Misoprostol. The antiglycogenolytic potency of both agonists was equal. It is concluded that the glycogenolytic and the antiglycogenolytic effects of prostaglandin E2 are mediated via different signalling pathways in hepatocytes possibly involving EP1 and EP3 prostaglandin E2 receptors, respectively.

Two-step thermal annealing processes were investigated for electrical activation of magnesium- doped galliumnitride layers. The samples were studied by room-temperature Hall measurements and photoluminescence spectroscopy at 16 K. After an annealing process consisting of a short-term step at 960 °C followed by a 600 °C dwell step for 5 min a resistivity as low as 0.84 Ω cm is achieved for the activated sample, which improves the results achieved by standard annealing (800 °C for 10 min) by 25% in resistivity and 100% in free hole concentration. Photoluminescence shows a peak centered at 3.0 eV, which is typical for Mg-doped samples with high free hole concentrations.

We report on photoassisted wet chemical formation of thin oxide films on n-GaN layers in potassium hydroxide based electrolytes at room temperature. The kinetics of the oxide formation and dissolution were examined via photocurrent transients. The tendency of the photocurrent to level out during photoelectrochemical etching experiments is associated with a quasiequilibrium state at the semiconductor/electrolyte interface. Homogeneous oxide films were grown in weak alkaline solutions (11

The calibration process of today's spark ignition (SI) engine control systems is a complex and cost-intensive procedure. One reason is that a large number of controller parameters in an Electronic Control Unit (ECU) should be optimized in the calibration process. To cope with increasing demands in control performance issues on the one hand and reduce calibration effort on the other hand, applications of two degree of freedoms (2DOF) control structures are gaining importance in control systems embedded in the SI-engine. In order to further reduce the time and effort needed in calibration, a performance indices based self tuning method for optimization of controller parameters is proposed. This method has been implemented in an ECU for tuning controller parameters in the rail pressure control loop. Results from the validation with test vehicles and on an engine test bench at IAV GmbH are shown.

Two main applications of term rewriting systems are equational reasoning in theorem provers and equational computation in programming languages. The present paper examines a number of term rewriting systems in terms of how rewriting is used in different implementations of theorem provers, the use of rewriting techniques in logic programming languages and the problem of efficiency. In addition a non-exhaustive catalogue of distributed implementations is presented

Gallium nitride has been reactive-ion etched with SF6 and argon plasmas. The Ar-etched samples show a striking transition from a dominant blue luminescence band to a dominant yellow luminescence band after less than 5 min of low power illumination. The observation of metastable defects which are associated with both the yellow and blue bands has important consequences for our understanding of defect-related luminescence in gallium nitride.

Temperature stress experiments up to 800/spl deg/C have been applied to AlGaN/GaN FET's grown by MOVPE on sapphire and their individual technological building blocks. It was found that the temperature limit is given by the irreversible degradation of the intrinsic active heterostructure material itself during operation above 600/spl deg/C. The irreversible degradation was observed for both unconnected and electrically operated devices during temperature stress.