Hour time-scale QPOs in the X-ray and radio emission of LS I +61∘^{\circ}303

LS I +61$^{\circ}$303 is an X-ray binary with a radio outburst every ~27 days. Previous studies of the stellar system revealed radio microflares superimposed on the large radio outburst. We present here new radio observations of LS I +61$^{\circ}$303 at 2.2 GHz with the Westerbork Synthesis Radio Telescope (WSRT). Using various timing analysis methods we find significant Quasi-Periodic Oscillations (QPOs) of 55 minutes stable over the duration of 4 days. We also use archival data obtained from the Suzaku satellite at X-ray wavelengths. We report here for the first time significant X-ray QPOs of about 2 hours present over the time span of 21 hours. We compare our results with the previously reported QPO observations and we conclude that the QPOs seem to be associated with the radio outburst, independent of the amplitude of the outburst. Finally, the different QPO time-scales are discussed in the context of magnetic reconnection

Stereo- and Regioselective Alkyne Hydrometallation with Gold(III) Hydrides

The hydroauration of internal and terminal alkynes by gold(III) hydride complexes [(C^N^C)AuH] was found to be mediated by radicals and proceeds by an unexpected binuclear outer-sphere mechanism to cleanly form trans-insertion products. Radical precursors such as azobisisobutyronitrile lead to a drastic rate enhancement. DFT calculations support the proposed radical mechanism, with very low activation barriers, and rule out mononuclear mechanistic alternatives. These alkyne hydroaurations are highly regio- and stereospecific for the formation of Z-vinyl isomers, with Z/E ratios of >99:1 in most cases

Dispersion, solvent and metal effects in the binding of gold cations to alkynyl ligands: implications for Au(i) catalysis.

The coordination modes of the [Au(PPh3)](+) cation to metal alkynyl complexes have been investigated. On addition to ruthenium, a vinylidene complex, [Ru(η(5)-C5H5)(PPh3)2([double bond, length as m-dash]C[double bond, length as m-dash]CPh{AuPPh3})](+), is obtained while addition to a gold(iii) compound gives di- and trinuclear gold complexes depending on the conditions employed. In the trinuclear species, a gold(i) cation is sandwiched between two gold(iii) alkynyl complexes, suggesting that coordination of multiple C-C triple bonds to gold is facile

Evaluierung und Verifikation einer Positionierungshilfe mittels Ultraschall für den Tiefenhyperthermie Applikator am Kantonsspital Aarau

Die Tiefenhyperthermie ist ein additives Verfahren welches bei Tumorerkrankungen neben Strahlen-/Chemotherapie angewendet werden kann. Ziel dieser Behandlung ist das Überwärmen der Tumorzellen um diese zu Schädigen und für die anderen Therapieformen empfindlicher zu machen. Um das umgebende Gewebe nicht zu schädigen wird die eingestrahlte Energie auf den Tumor fokussiert. Dafür muss jeder Patient exakt im Hyperthermie-Applikator platziert werden. Aus dieser Vorraussetzung ergibt sich die Problemstellung dieser Arbeit. Um den Vorraussetzungen bei der zukünftigen Therapeiplanung mit der Software Sigma Hyperlan gerrecht zu werden, soll die im Kantonsspital angewandte Methode mittels Messung per Lineal in vertikaler Richtung (Y-Richtung) durch ein genaueres Verfahren ersetzt werden Die europäischen Richtlinien geben eine Genauigkeit von ±1cm in den jeweiligen Richtungen vor. Im Hauptteil dieser Arbeit werden verschiedene Methoden der Abstandsmessung für diese Aufgabe diskutiert und ein Verfahren per Ultraschall durch mehrere Messversuche, im Wasserbecken und am HT-Applikator, auf Eignung geprüft. Hierbei wird die Abstandsmessung des Ultraschallgerätes, unter den diversen Einflüssen der Messumgebung, auf Abweichung überprüft. Außerdem werden weitergehende Versuche durchgefürt um zusätzliche Messungen auf realisierbarkeit zu prüfen und dadurch weitere Informationen während der Behandlung zu dokumentieren. Im Ergebnis konnten die Abstände mit geforderter Genauigkeit per Ultraschall vom Patienten relativ zum Applikator bestimmt werden. Für die Zukunft gilt es die Reproduzierbarkeit der Messungen in Winkel und Position im Vergleich zur Abstandsmessung in der Software für jede Behandlung, z.B. mittels einer Halterung an Oberfläche des Applikator, zu verbessern

Clinically Applicable Quantitative Magnetic Resonance Morphologic Measurements of Grey Matter Changes in the Human Brain

(1) Purpose: Quantitative magnetic resonance imaging (qMRI) measurements can be used to sensitively estimate brain morphological alterations and may support clinical diagnosis of neurodegenerative diseases (ND). We aimed to establish a normative reference database for a clinical applicable quantitative MR morphologic measurement on neurodegenerative changes in patients; (2) Methods: Healthy subjects (HCs, n = 120) with an evenly distribution between 21 to 70 years and amyotrophic lateral sclerosis (ALS) patients (n = 11, mean age = 52.45 ± 6.80 years), as an example of ND patients, underwent magnetic resonance imaging (MRI) examinations under routine diagnostic conditions. Regional cortical thickness (rCTh) in 68 regions of interest (ROIs) and subcortical grey matter volume (SGMV) in 14 ROIs were determined from all subjects by using Computational Anatomy Toolbox. Those derived from HCs were analyzed to determine age-related differences and subsequently used as reference to estimate ALS-related alterations; (3) Results: In HCs, the rCTh (in 49/68 regions) and the SGMV (in 9/14 regions) in elderly subjects were less than those in younger subjects and exhibited negative linear correlations to age (p < 0.0007 for rCTh and p < 0.004 for SGMV). In comparison to age- and sex-matched HCs, the ALS patients revealed significant decreases of rCTh in eight ROIs, majorly located in frontal and temporal lobes; (4) Conclusion: The present study proves an overall grey matter decline with normal ageing as reported previously. The provided reference may be used for detection of grey matter alterations in neurodegenerative diseases that are not apparent in standard MR scans, indicating the potential of using qMRI as an add-on diagnostic tool in a clinical setting