Quantitative investigations of in-cylinder flow fields, gas-phase temperatures, and early flame propagation via spatially resolved measurement techniques

Optische in-situ Messtechniken ermöglichen eine berührungsfreie räumliche und zeitliche Analyse der hoch instationären Vorgänge in Verbrennungsmotoren. Abbildende innermotorische Messungen von Strömungsgeschwindigkeiten, Gasphasentemperaturfluktuationen und Flammenausbreitung sind Schwerpunkt dieser Arbeit. In einem optisch zugänglichen Einzylinder-Ottomotor wurden die für den Wandwärmeübergang und die Selbstzündkinetik wichtigen vektoriellen und wandnahen skalaren Grö-ßen hochaufgelöst und quantitativ abgebildet. Zusätzlich wurde in Experimenten der Einfluss zykli-scher Schwankungen auf die frühe Flammenausbreitung untersucht, sowie die Interaktion der Flam-menfront mit dem Feuerstegvolumen analysiert. Als ortsaufgelöste quantitative Messtechniken wurden Particle Image Velocimetry (PIV) und laserinduzierte Tracerfluoreszenz (Tracer-LIF) eingesetzt. Für die Visualisierung der Zündung und der frühen und späten Flammenausbreitung wurde das Eigen-leuchten der Verbrennung bei kHz-Raten detektiert. Der Großteil der experimentell gewonnenen Da-tensätze floss in die Validierung von Grobstruktursimulationen (LES) bei verschiedenen Projektpart-nern ein, deren Ergebnisse hier zusammenfassend dargestellt sind. Neben den Untersuchungen am optisch zugänglichen Verbrennungsmotor wurden weitere Strömungs-messungen an einem stationär durchströmten Zylinderkopf mit gleicher Geometrie durchgeführt. Der Fokus dieser Experimente lag dabei auf einer systematischen Analyse der Einlassströmung. Die lokale Strömungsablösung am Einlassventil und Ventilspalt sowie die nachfolgende Ausbildung (teil)kohärenter Strömungsstrukturen im Zylinder wurden dabei mithilfe räumlich hochauflösender PIV bei unterschiedlichen Einlassrandbedingungen untersucht.Non-intrusive optical in-situ diagnostics enable detailed analysis of the unsteady processes in internal combustion engines. The focus of this work were two-dimensional measurements of flow velocities, gas-temperature fluctuations, and flame propagation in an IC engine. The quantities relevant for wall-heat transfer and auto ignition were imaged with high resolution in an optically accessible single-cylinder spark-ignited engine. Also, the impact of cyclic variability on early flame propagation was studied, as well as the interaction of the flame front with the top-land crevice volume. Particle image velocimetry (PIV) and laser-induced tracer fluorescence (tracer-LIF) were applied for quantitative two-dimensional measurements. For the visualization of ignition and early and late flame propagation, chemiluminescence was imaged at kHz rates. The majority of the recorded datasets was used to validate large-eddy simulations (LES) of collaborators, whose results are briefly summarized for reference. In addition to the investigations in the optically accessible IC engine, further flow measurements were carried out in a cylinder head with the same geometry on a flow bench. The focus of these experiments was on a systematic analysis of intake flow. The local flow separation at the intake valve and the valve gap as well as the subsequent formation of semi-coherent flow structures in the cylinder were studied for a range of intake conditions using high-resolution two-component PIV

Attosecond Photoionization Dynamics: from Molecules over Clusters to the Liquid Phase

Photoionization is a process taking place on attosecond time scales. How its properties evolve from isolated particles to the condensed phase is an open question of both fundamental and practical relevance. Here, we review recent work that has advanced the study of photoionization dynamics from atoms to molecules, clusters and the liquid phase. The first measurements of molecular photoionization delays have revealed the attosecond dynamics of electron emission from a molecular shape resonance and their sensitivity to the molecular potential. Using electron-ion coincidence spectroscopy these measurements have been extended from isolated molecules to clusters. A continuous increase of the delays with the water-cluster size has been observed up to a size of 4-5 molecules, followed by a saturation towards larger clusters. Comparison with calculations has revealed a correlation of the time delay with the spatial extension of the created electron hole. Using cylindrical liquid-microjet techniques, these measurements have also been extended to liquid water, revealing a delay relative to isolated water molecules that was very similar to the largest water clusters studied. Detailed modeling based on Monte-Carlo simulations confirmed that these delays are dominated by the contributions of the first two solvation shells, which agrees with the results of the cluster measurements. These combined results open the perspective of experimentally characterizing the delocalization of electronic wave functions in complex systems and studying their evolution on attosecond time scales

No Consensus on Definition Criteria for Stroke Registry Common Data Elements

www.karger.com/cee This is an Open Access article licensed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License (www.karger.com/OA-license), applicable to the online version of the article only. Distribution for non-commercial purposes only

Radiotherapy for Metastatic Epidural Spinal Cord Compression with Increased Doses: Final Results of the RAMSES-01 Trial

Simple Summary Patients with MESCC and favorable survival prognoses assigned to radiotherapy alone may benefit from increased doses. In a multi-center phase 2 trial, patients receiving 15 x 2.633 Gy or 18 x 2.333 Gy were evaluated and subsequently compared to a historical control group receiving 10 x 3.0 Gy. The phase 2 cohort, including 50 (of 62 planned) evaluable patients, showed promising results regarding 12-month local progression-free survival (LPFS), 12-month overall survival (OS), improvement of motor and sensory functions, post-radiotherapy ambulatory status, and relief of pain and distress. Radiotherapy with 15 x 2.633 Gy or 18 x 2.333 Gy was well tolerated and appeared more effective than 10 x 3.0 Gy with respect to LPFS and improvement of motor function.Abstract Patients with metastatic epidural spinal cord compression (MESCC) and favorable survival prognoses may benefit from radiation doses exceeding 10 x 3.0 Gy. In a multi-center phase 2 trial, patients receiving 15 x 2.633 Gy (41.6 Gy10) or 18 x 2.333 Gy (43.2 Gy10) were evaluated for local progression-free survival (LPFS), motor/sensory functions, ambulatory status, pain, distress, toxicity, and overall survival (OS). They were compared (propensity score-adjusted Cox regression) to a historical control group (n = 266) receiving 10 x 3.0 Gy (32.5 Gy10). In the phase 2 cohort, 50 (of 62 planned) patients were evaluated for LPFS. Twelve-month rates of LPFS and OS were 96.8% and 69.9%, respectively. Motor and sensory functions improved in 56% and 57.1% of patients, and 94.0% were ambulatory following radiotherapy. Pain and distress decreased in 84.4% and 78.0% of patients. Ten and two patients experienced grade 2 and 3 toxicities, respectively. Phase 2 patients showed significantly better LPFS than the control group (p = 0.039) and a trend for improved motor function (p = 0.057). Ambulatory and OS rates were not significantly different. Radiotherapy with 15 x 2.633 Gy or 18 x 2.333 Gy was well tolerated and appeared superior to 10 x 3.0 Gy

The Wolf-Rayet population of the nearby barred spiral galaxy NGC 5068 uncovered by the Very Large Telescope and Gemini

We present a narrow-band Very Large Telescope/Focal Reduced Low-dispersion Spectrograph #1 imaging survey of the SAB(rs)cd spiral galaxy NGC 5068, located at a distance of 5.45 Mpc, from which 160 candidate Wolf–Rayet sources have been identified, of which 59 cases possess statistically significant λ4686 excesses. Follow-up Gemini Multi-Object Spectrograph spectroscopy of 64 candidates, representing 40 per cent of the complete photometric catalogue, confirms Wolf–Rayet signatures in 30 instances, corresponding to a 47 per cent success rate. 21 out of 22 statistically significant photometric sources are spectroscopically confirmed. Nebular emission detected in 30 per cent of the Wolf–Rayet candidates spectrally observed, which enable a re-assessment of the metallicity gradient in NGC 5068. A central metallicity of log (O/H) + 12 ∼ 8.74 is obtained, declining to 8.23 at R25. We combine our spectroscopy with archival Hα images of NGC 5068 to estimate a current star formation rate of Graphic, and provide a catalogue of the 28 brightest H ii regions from our own continuum subtracted Hα images, of which ∼17 qualify as giant H ii regions. Spectroscopically, we identify 24 WC- and 18 WN-type Wolf–Rayet stars within 30 sources since emission-line fluxes indicate multiple Wolf–Rayet stars in several cases. We estimate an additional ∼66 Wolf–Rayet stars from the remaining photometric candidates, although sensitivity limits will lead to an incomplete census of visually faint WN stars, from which we estimate a global population of ∼170 Wolf–Rayet stars. Based on the Hα-derived O star population of NGC 5068 and N(WR)/N(O) ∼ 0.03, representative of the Large Magellanic Cloud, we would expect a larger Wolf–Rayet population of 270 stars. Finally, we have compared the spatial distribution of spectroscopically confirmed WN and WC stars with Sloan Digital Sky Survey derived supernovae, and find both WN and WC stars to be most consistent with the parent population of Type Ib supernovae

17α-hydroxylase deficiency diagnosed in early infancy caused by a novel mutation of the CYP17A1 Gene

Mutations of the CYP17A1 gene cause 17α-hydroxylase deficiency (17OHD) resulting in 46,XY disorder of sex development, hypertension, hypokalemia and absent pubertal development. It is a rare, autosomal recessive form of congenital adrenal hyperplasia (CAH).We report on a neonate with prenatally determined 46,XY karyotype. At 20 weeks of gestation, lack of development of male external genitalia was noticed. A phenotypically female child was born at 41 weeks of gestation.Postnatal ultrasound revealed testes in both labia majora, an absence of uterus and normal adrenal glands. Steroid hormone analysis in serum revealed low basal levels of cortisol, testosterone and androstenedione in the presence of massively elevated corticosterone at the age of 2 weeks. The urinary steroid profile from spot urine showed excessive excretion of 17-desoxysteroids, decreased glucocorticoid metabolites and absent C19 steroids, thus proving 17OHD. Molecular analysis identified a novel mutation of the CYP17A1 gene: c.896T>A (p.I299N) in exon 5. Substitution with hydrocortisone was started. The child is raised as a girl and is developing well so far.Herein, we report the unusually early diagnosis of a newborn with the rare CAH form of 17OHD allowing an early start of treatment

Seasonal Evolution of the Subglacial Hydrologic System Modified by Supraglacial Lake Drainage in Western Greenland

The impact of summer surface melt on the dynamics of the Greenland Ice Sheet is modulated by the state of the subglacial hydrologic system. Studies of ice motion indicate that efficiency of the subglacial system increases over the melt season, decreasing the sensitivity of ice motion to surface melt. However, these inferences are based on limited indirect observations of the subglacial hydrologic system that leave many factors poorly constrained, particularly the presence and stability of subglacial channels. Here we use observations from 11 GPS stations, from which we derive ice velocity, longitudinal strain rates, and basal uplift, alongside observations of surface ablation and supraglacial lake drainage events, to explore the coevolution of ice motion and the subglacial hydrologic system in the Pakitsoq region of western Greenland during the 2011 melt season. We observe ice acceleration after the onset of local surface melting, followed by gradual ice deceleration, consistent with the pattern expected from increased subglacial drainage efficiency. Supraglacial lake drainages appear to precipitate ice deceleration and increased basal traction, suggesting that lake drainages effectively reorganize the local subglacial hydrologic system into a more efficient state that persists through the remainder of the melt season. At high elevations, ice velocity and inferred basal uplift suggest that continued cavity growth or sediment behavior, not subglacial channelization, drive the apparent increase in subglacial efficiency. Our results further indicate that these transient perturbations are critical in the seasonal evolution of ice motion

Primordial statistical anisotropy generated at the end of inflation

We present a new mechanism for generating primordial statistical anisotropy of curvature perturbations. We introduce a vector field which has a non-minimal kinetic term and couples with a waterfall field in hybrid inflation model. In such a system, the vector field gives fluctuations of the end of inflation and hence induces a subcomponent of curvature perturbations. Since the vector has a preferred direction, the statistical anisotropy could appear in the fluctuations. We present the explicit formula for the statistical anisotropy in the primordial power spectrum and the bispectrum of curvature perturbations. Interestingly, there is the possibility that the statistical anisotropy does not appear in the power spectrum but does appear in the bispectrum. We also find that the statistical anisotropy provides the shape dependence to the bispectrum.Comment: 9 pages, This version supersedes the JCAP version. Minor revision