Influence of cross correlations on interdiffusion in Al-rich Al-Ni melts

The relation of self- and interdiffusion in a liquid metal, particularly the influence of cross correlations at low concentrations, is studied experimentally. Accurate interdiffusion data are obtained by a combination of x-ray radiography with the shear-cell method on the ground and on the sounding rocket MAPHEUS under microgravity conditions. Self-diffusion coefficients, measured by quasielastic neutron scattering, increase with decreasing Ni concentration, whereas interdiffusion coefficients are about constant. We show that cross correlations influence interdiffusion even at concentrations as low as 2 at. % Ni. Consequently, Darken's equation is not valid in this case

Pharmacokinetics of gamithromycin in pigs

Objectives : Gamithromycin, a 15-membered semi-synthetic macrolide antibiotic of the azalide subclass, has recently been developed for the treatment and prevention of bovine respiratory disease (BRD). Besides the anti-infectious properties, macrolides have frequently been reported to be able to influence various inflammatory processes, such as the production of pro-inflammatory cytokines and mediators. The aim of this study was to determine the pharmacokinetic (PK) parameters of gamithromycin in pigs, whereafter the disposition of the antibiotic can be used in further research to investigate its immunomodulating properties in a porcine lipopolysaccharide (LPS) inflammation model. Materials and Methods : Twelve male pigs, with a mean body weight (BW) of 24.4 kg were randomly divided in two groups. The animals received a single injection of 6 mg/kg BW gamithromycin (ZACTRAN®, Merial), either intravenously (IV) in the ear vein (n = 6) or subcutaneously (SC) (n = 6). Blood was collected from the jugular vein into EDTA tubes before administration; on day 0 at 15, 30 and 45 minutes and 1, 2, 4, 6, 8, 10, 12 and 24 h post administration (p.a.) and once daily from day 2 to day 14 p.a. (24 h intervals). Plasma was isolated and stored at ≤ -15°C until analysis. Quantitation of gamithromycin in the plasma samples was performed using an in-house developed and validated LC-MS/MS method. The pharmacokinetic parameters were analyzed using the software program WinNonlin (Pharsight). Results and Conclusions : The area under the plasma concentration-time curve (AUC0→∞), absolute bioavailability (F), half-life of absorption and elimination (t1/2abs and t1/2el, respectively), volume of distribution (Vd), clearance (Cl), maximum plasma concentration (Cmax) and time to Cmax (Tmax) were determined and critically compared to the PK parameters in cattle and foals1,2. Results and conclusions will be presented at the congress. References 1. Huang et al., 2010, J. vet. Pharmacol. Therap. 33(3), 227-237 2. Berghaus et al., 2012, J. vet. Pharmacol. Therap. 35(1), 59-6

Prekäre Professionalität: Soziale Arbeit und die Coronapandemie

Die Coronapandemie hat und hatte auf alle Bereiche des menschlichen Lebens erheblichen Einfluss - insbesondere auch auf den Arbeitsalltag. Die Autor*innen untersuchen mit vier empirischen Studien in unterschiedlichen Phasen der Coronapandemie die Arbeitsbedingungen in der Sozialen Arbeit. Auf diese Weise zeichnen sie die Veränderungen in beruflichen Abläufen, den zunehmenden Druck im Alltag sowie den wachsenden Bedarf bei den Adressat*innen nach. Die Analyse zeigt: Die professionelle Autonomie der Beschäftigten wird eingeschränkt, etablierte Verfahren sind außer Kraft gesetzt und Kooperationen zum Erliegen gekommen. Das Buch fragt deshalb nach den langfristigen Folgen der Coronapandemie für die Soziale Arbeit: Entwickelt sich da eine prekäre Professionalität, in der die Beschäftigten keine Chancen zur Verwirklichung fachlich angemessener Entscheidungen und Maßnahmen mehr haben? Das Buch zeichnet die Veränderungen in den Arbeitsbedingungen und Handlungsweisen in der Sozialen Arbeit vom ersten Lockdown 2020 bis zum Wegfall der meisten Schutzmaßnahmen im Herbst 2022 nach. Vor diesem Hintergrund gehen die Autor*innen der Frage nach, ob diese Prozesse dauerhafte Auswirkungen auf das professionelle Handeln die Professionalität der Beschäftigten in der Sozialen Arbeit haben. Damit zusammenhängend lassen sich auch Einblicke in die Lebenswelt der Adressat*innen gewinnen, hängen doch diese beiden Dimensionen mittelbar miteinander zusammen. Das Ziel des Buches besteht in der Herstellung von Sprachfähigkeit einerseits innerhalb der Berufsgruppe und andererseits nach außen. Gerade bei der fehlenden Sprechfähigkeit der Sozialen Arbeit hat die Coronapandemie deutliche Probleme aufgezeigt

New Analyzing Approaches for In Situ Interdiffusion Experiments to Determine Concentration-Dependent Diffusion Coefficients in Liquid Al-Au

Interdiffusion coefficients are key parameters for the solidification process of liquid alloys. However, the determination of interdiffusion coefficients in liquid metals at high temperatures is a challenging and extensive task, due to a variety of potential systematic errors. In recent years we have developed an X-ray in situ shear cell method for the measurement of interdiffusion coefficients in binary metallic melts. This technique enables the monitoring of the experiment in order to exclude fatal errors. Utilizing X-ray contrast, the method also provides a time-resolved concentration distribution. Such an in situ data set contains significantly more information than ex situ evaluated experiments. Available analyzing strategies do not fully exploit this potential yet. We present three new analyzing approaches that are able to retrieve a concentration-dependent interdiffusion coefficient from only one in situ data set. In that way, larger concentration differences become accessible for an experiment, which considerably decreases efforts. Using simulations, the approaches are checked for robustness. Furthermore, the approaches are run on real in situ data from a binary (0 to 9 at% Au-content) Al-Au alloy at 1000 °C which results in a concentration-dependent interdiffusion coefficient within the measured concentration range

Influence of Gravity on Atomic Mobility in a Liquid

Measurements of diffusion and thermodiffusion in liquids are very sensitive to convection caused for example by buoyancy. To reduce the impact of buoyancy-driven convection, benchmark experiments are performed in microgravity conditions. Here, we discuss the general influence of gravity on atomic mobility. The gravitational Peclet number and the gravitational length can be used to assess this influence. They show that the diffusion processes of atoms in a liquid is not affected by Earth’s gravitational force but that the process is dominated by the thermal energy of the atoms. Data from experiments under different gravity conditions ranging from 10^-5 g to 10^6 g are summarized. They confirm that interdiffusion is only influenced by accelerations that are orders of magnitude larger than Earth’s gravity

Variability and Proper Motion of X-ray Knots in the Jet of Centaurus A

Accepted to ApJ, 14 pages, 8 figures, 2 tablesWe report results from Chandra observations analyzed for evidence of variability and proper motion in the X-ray jet of Centaurus A. Using data spanning 15 yr, collective proper motion of 11.3 ± 3.3 mas yr -1 , or 0.68 ± 0.20c, is detected for the fainter X-ray knots and other substructure present within the jet. The three brightest knots (AX1A, AX1C, and BX2) are found to be stationary to an upper limit of . Brightness variations up to 27% are detected for several X-ray knots in the jet. For the fading knots, BX2 and AX1C, the changes in spectral slope expected to accompany synchrotron cooling are not found, ruling it out and placing upper limits of ≃80 μG for each of their magnetic field strengths. Adiabatic expansion can account for the observed decreases in brightness. Constraints on models for the origin of the knots are established. Jet plasma overrunning an obstacle is favored as the generator of stationary knots, while moving knots are likely produced either by internal differences in jet speed or the late stages of jet interaction with nebular or cloud material.Peer reviewe