Processing of biocompatible materials on a polymer basis by a lowtemperature plasma at atmospheric pressure

In the present work we investigated the effect of low-temperature treatment in the flow of argon on composite materials based on Poly-L-lactide/Hydroxyapatite (PL/HA) in the ratio of 70/30 and hydroxyapatite and lactide and glycolide copolymer (SLG-HA) in the ratio of 10/90. Physical-chemical properties were obtained by investigation of phase state of the modified surface layer by X-ray analysis, chemical composition by IR-spectroscopy, as well as contact angle

Erhöhung der Korrelation zwischen BCI- und Antennenprüfverfahren durch Bestimmung von Abschlussimpedanzen mittels potenzialfreier Messung mit Stromsensoren

Der Nachweis der Störfestigkeit gegen gestrahlte Felder muss häufig durch eine Antennenprüfung (ALSE, [1]) in einer elektromagnetisch abgeschirmten Messumgebung mit geringen Reflexionen erbracht werden. Hohe Kosten und ein entsprechender Raumbedarf für die Absorberkabine sind mit diesem Verfahren verbunden. Außerdem kann die kalibrierte Feldstärke für bestimmte Frequenzen und Polarisierungen sehr empfindlich auf kleine Änderungen des Aufbaus reagieren [1]. Dies erhöht deutlich den Zeitaufwand und die Komplexität des ALSE-Verfahrens und erschwert die Reproduktion eines Messergebnisses. Als Alternative bietet sich das Strominjektionsverfahren (BCI, [2]) an, bei dem ein Magnetfeld in der BCI-Zange einen HF-Strom in einen Kabelbaum induziert. Obwohl der Aufbau des Prüflings, des Prüfkabelbaumes und anderer Peripheriegeräte auf dem Prüftisch (Abbildung 1rechts) in beiden Verfahren identisch erfolgt, ist leider die Vergleichbarkeit der Verfahren oft nicht gegeben [3,4]. In Abbildung 1-links sind die gemessenen Stromverläufe am Ende einer Einfachleitung in einem Testaufbau nach Norm für die beiden Testmethoden gegenübergestellt. Es ist ersichtlich, dass verschiedene Koppelmechanismen in den beiden Verfahren zu verschiedenen Störstromverläufen am DUT (Device Under Test)-Eingang führen. Die Ströme am DUT-Eingang und evtl. auf der Seite der für den Betrieb des DUT notwendigen „Load-Box“ sind für einen Ausfall verantwortlich. Die unterschiedlichen Amplituden können durch eine frequenzabhängige Anpassung der eingespeisten Leistung angepasst werden. Durch eine Verschiebung der BCI-Zange entlang der Leitung, bekommt man einen weiteren Freiheitsgrad, der die Anpassung des Stroms sogar auf beiden Seiten erlauben kann. Damit kann die Korrelation zwischen den BCIund Antennenprüfverfahren deutlich erhöht werden. In [5] sind zwei Verfahren für die Bestimmung der Position und der Einspeiseleistung der BCI-Zange vorgestellt. Für die Auswahl dieser Parameter ist es notwendig, die Impedanz der Abschlüsse zu kennen, was in der Praxis ein Problem darstellt. Eine direkte Bestimmung der Abschlussimpedanzen ist nicht zielführend, da der zusätzliche Messaufwand zu hoch wäre. Die Bestimmung der Abschlussimpedanz sollte im tatsächlichen Testaufbau mit einer potenzialfreien Messmethode durchgeführt werden können. Induktive Verfahren sind hierfür besonders geeignet. In diesem Beitrag werden Verfahren für die induktive Impedanzmessung an einer Testleitung unter Verwendung eines Stromsensors oder der BCI-Einkoppelzange als Messmittel vorgestellt und ausführlich diskutiert

Realistic Threat Models for Satellite-Based Quantum Key Distribution

The security of prepare-and-measure satellite-based quantum key distribution (QKD), under restricted eavesdropping scenarios, is addressed. We particularly consider cases where the eavesdropper, Eve, has limited access to the transmitted signal by Alice, and/or Bob's receiver station. This restriction is modeled by lossy channels between Alice/Bob and Eve, where the transmissivity of such channels can, in principle, be bounded by monitoring techniques. An artefact of such lossy channels is the possibility of having bypass channels, those which are not accessible to Eve, but may not necessarily be characterized by the users either. This creates interesting, {\it unexplored}, scenarios for analyzing QKD security. In this paper, we obtain generic bounds on the key rate in the presence of bypass channels and apply them to continuous-variable QKD protocols with Gaussian encoding with direct and reverse reconciliation. We find regimes of operation in which the above restrictions on Eve can considerably improve system performance. We also develop customised bounds for several protocols in the BB84 family and show that, in certain regimes, even the simple protocol of BB84 with weak coherent pulses is able to offer positive key rates at high channel losses, which would otherwise be impossible under an unrestricted Eve. In this case the limitation on Eve would allow Alice to send signals with larger intensities than the optimal value under an ideal Eve, which effectively reduces the effective channel loss. In all these cases, the part of the transmitted signal that does not reach Eve can play a non-trivial role in specifying the achievable key rate. Our work opens up new security frameworks for spaceborne quantum communications systems.Comment: 39 pages, 17 figure

Sampling QCD field configurations with gauge-equivariant flow models

Machine learning methods based on normalizing flows have been shown to address important challenges, such as critical slowing-down and topological freezing, in the sampling of gauge field configurations in simple lattice field theories. A critical question is whether this success will translate to studies of QCD. This Proceedings presents a status update on advances in this area. In particular, it is illustrated how recently developed algorithmic components may be combined to construct flow-based sampling algorithms for QCD in four dimensions. The prospects and challenges for future use of this approach in at-scale applications are summarized

Is it possible to improve residents breaking bad news skills? A randomised study assessing the efficacy of a communication skills training program

info:eu-repo/semantics/publishe

Hydrogen Epoch of Reionization Array (HERA)

The Hydrogen Epoch of Reionization Array (HERA) is a staged experiment to measure 21 cm emission from the primordial intergalactic medium (IGM) throughout cosmic reionization ($z=6-12$), and to explore earlier epochs of our Cosmic Dawn ($z\sim30$). During these epochs, early stars and black holes heated and ionized the IGM, introducing fluctuations in 21 cm emission. HERA is designed to characterize the evolution of the 21 cm power spectrum to constrain the timing and morphology of reionization, the properties of the first galaxies, the evolution of large-scale structure, and the early sources of heating. The full HERA instrument will be a 350-element interferometer in South Africa consisting of 14-m parabolic dishes observing from 50 to 250 MHz. Currently, 19 dishes have been deployed on site and the next 18 are under construction. HERA has been designated as an SKA Precursor instrument. In this paper, we summarize HERA's scientific context and provide forecasts for its key science results. After reviewing the current state of the art in foreground mitigation, we use the delay-spectrum technique to motivate high-level performance requirements for the HERA instrument. Next, we present the HERA instrument design, along with the subsystem specifications that ensure that HERA meets its performance requirements. Finally, we summarize the schedule and status of the project. We conclude by suggesting that, given the realities of foreground contamination, current-generation 21 cm instruments are approaching their sensitivity limits. HERA is designed to bring both the sensitivity and the precision to deliver its primary science on the basis of proven foreground filtering techniques, while developing new subtraction techniques to unlock new capabilities. The result will be a major step toward realizing the widely recognized scientific potential of 21 cm cosmology.Comment: 26 pages, 24 figures, 2 table

Carbamylated low-density lipoprotein induces endothelial dysfunction

Aims Cardiovascular events remain the leading cause of death in Western world. Atherosclerosis is the most common underlying complication driven by low-density lipoproteins (LDL) disturbing vascular integrity. Carbamylation of lysine residues, occurring primarily in the presence of chronic kidney disease (CKD), may affect functional properties of lipoproteins; however, its effect on endothelial function is unknown. Methods and results Low-density lipoprotein from healthy donors was isolated and carbamylated. Vascular reactivity after treatment with native LDL (nLDL) or carbamylated LDL (cLDL) was examined in organ chambers for isometric tension recording using aortic rings of wild-type or lectin-like-oxidized LDL receptor-1 (LOX-1) transgenic mice. Reactive oxygen species (ROS) and nitric oxide (NO) production were determined using electron spin resonance spectroscopy. The effect of LDL-carbamyl-lysine levels on cardiovascular outcomes was determined in patients with CKD during a median follow-up of 4.7 years. Carbamylated LDL impaired endothelium-dependent relaxation to acetylcholine or calcium-ionophore A23187, but not endothelium-independent relaxation to sodium nitroprusside. In contrast, nLDL had no effect. Carbamylated LDL enhanced aortic ROS production by activating NADPH-oxidase. Carbamylated LDL stimulated endothelial NO synthase (eNOS) uncoupling at least partially by promoting S-glutathionylation of eNOS. Carbamylated LDL-induced endothelial dysfunction was enhanced in LOX-1 transgenic mice. In patients with CKD, LDL-carbamyl-lysine levels were significant predictors for cardiovascular events and all-cause mortality. Conclusions Carbamylation of LDL induces endothelial dysfunction via LOX-1 activation and increased ROS production leading to eNOS uncoupling. This indicates a novel mechanism in the pathogenesis of atherosclerotic disease which may be pathogenic and prognostic in patients with CKD and high plasma levels of cLD