EPR, ENDOR, and TRIPLE resonance studies of modified bacteriochlorophyll cation radicals

A series of substituted bacteriochlorophyll molecules, all used in reconstitution experiments of reaction centers of Rhodobacter sphaeroides (Struck et al. Biochim. Biophys. Acta 1991, 1060, 262-270), were characterized by EPR, electron-nuclear double (ENDOR), and electron-nuclear-nuclear triple (TRIPLE) resonance spectroscopy in their monomeric radical cation states. Effects of different substituents at position 3 in the porphyrin macrocycle were considered, especially for two «crosslinks» between plant and bacterial chlorophylls. These are 3-vinylbacteriochlorophyll where the «bacteria» acetyl group at position 3 was substituted by vinyl and 3-acetylchlorophyll where the «plant» vinyl group was substituted by acety

Impact of Quantitative Feedback via High-Fidelity Airway Management Training on Success Rate in Endotracheal Intubation in Undergraduate Medical Students—A Prospective Single-Center Study

Endotracheal intubation is still the gold standard in airway management. For medical students and young professionals, it is often difficult to train personal skills. We tested a high-fidelity simulator with an additional quantitative feedback integration to elucidate if competence acquisition for airway management is increased by using this feedback method. In the prospective trial, all participants (n = 299; 4th-year medical students) were randomized into two groups—One had been trained on the simulator with additional quantitative feedback (n = 149) and one without (n = 150). Three simulator measurements were considered as quality criteria—The pressure on the upper front row of teeth, the correct pressure point of the laryngoscope spatula and the correct depth for the fixation of the tube. There were a total of three measurement time points—One after initial training (with additional capture of cognitive load), one during the exam, and a final during the follow-up, approximately 20 weeks after the initial training. Regarding the three quality criteria, there was only one significant difference, with an advantage for the control group with respect to the correct pressure point of the laryngoscope spatula at the time of the follow-up (p = 0.011). After the training session, the cognitive load was significantly higher in the intervention group (p = 0.008) and increased in both groups over time. The additional quantitative feedback of the airway management trainer brings no measurable advantage in training for endotracheal intubation. Due to the increased cognitive load during the training, simple airway management task training may be more efficient for the primary acquisition of essential procedural steps

Wer gewinnt durch die geplante Föderalismusreform?

Die Föderalismusreform soll die Zuständigkeiten von Bund und Ländern entflechten und für mehr Transparenz sorgen. Wer sind die Gewinner und wer sind die Verlierer der geplanten Änderung? Margret Wintermantel, Präsidentin der Hochschulrektorenkonferenz, befürchtet, dass die Hochschulen die Verlierer der Föderalismusreform sein könnten: "Würde die im Koalitionsvertrag beabsichtigte Föderalismusreform so umgesetzt, wie derzeit geplant, würde dies Nachteile für die Hochschulen in Deutschland mit sich bringen." Auch Hans-Peter Schneider, Universität Hannover, sieht nicht nur Gewinner, sondern auch Verlierer, meist sogar "in beiderlei Gestalt zugleich". Für ihn sind Vor- und Nachteile der Reform bei der einen oder anderen Seite nicht eindeutig zu verbuchen. Für Peter Struck, SPD-Bundestagsfraktion, dagegen werden die Reformziele - stärkere Kompetenztrennung, Abschaffung der Rahmengesetzgebung, Senkung der Zustimmungsquoten von Bundesgesetzen und Neuordnung der Finanzverantwortung von Bund und Ländern, insbes. gegenüber der EU - mit dem vorliegenden Gesamtpaket weitgehend erreicht, so dass sowohl Bund und Länder als auch die Bürger die Gewinner der Reform sind. Diese Ansicht teilt auch Wolfgang Bosbach, CDU/CSU-Bundestagsfraktion. Für ihn ist die Liste derer, die heute objektiv zu den Gewinnern der Reform zu zählen sind, ebenfalls "durchaus stattlich", während Joachim Wieland, Universität Frankfurt, auch Verlierer identifiziert: "Verlierer der Reform werden in gewissem Umfang die Ministerpräsidenten der Länder und ihre Regierungen sein. Ihnen wird die Bühne Bundesrat nur noch in weniger Fällen als gegenwärtig offen stehen."Föderalismus, Reform, Kompetenz, Staat, Hochschule, Gemeinde, Deutschland

Gradual warming prior to the end‐Permian mass extinction

The biggest known mass extinction in the history of animal life occurred at the Permian–Triassic boundary and has often been linked to global warming. Previous studies have suggested that a geologically rapid (<40 kyr) temperature increase of more than 10°C occurred simultaneously with the main extinction pulse. This hypothesis is challenged by geochemical and palaeontological data indicating profound environmental perturbations and a temperature rise prior to the main extinction. Using secondary ion mass spectrometry (SIMS), we measured oxygen isotope ratios from Changhsingian (late Permian) ostracods of north‐western Iran. Our data show that ambient seawater temperature began to rise at least 300 kyr prior to the main extinction event. Gradual warming by approximately 12°C was probably responsible for initial environmental degradation that eventually culminated in the global end‐Permian mass extinction

Formation of SRP-like particle induces a conformational change in E. coli 4.5S RNA

E. coli P48 protein is homologous to the SRP54 component of the eukaryotic signal recognition particle. In vivo, P48 is associated with 4.5S RNA which shares a homology with eukaryotic SRP RNA. To study the interaction between P48 and 4.5S RNA in vitro, we used 4.5S RNA with fluorescein coupled to the 3'-terminal ribose. Upon binding of P48, the fluorescent 4.5S RNA shows a substantial decrease in fluorescence. Fluorescence quenching as well as anisotropy measurements reveal that the effect is not due to a direct interaction of P48 with the dye. This suggests that the binding of P48 induces a conformational change in 4.5S RNA which affects the structure at the 3' end of the RNA. From equilibrium titrations with fluorescent 4.5S RNA, a dissociation constant of 0.15 microns is obtained for the RNA.protein complex. The formation of the complex is not affected by GTP binding to or hydrolysis by P48

Observation of Bose-Einstein Condensation in a Strong Synthetic Magnetic Field

Extensions of Berry's phase and the quantum Hall effect have led to the discovery of new states of matter with topological properties. Traditionally, this has been achieved using gauge fields created by magnetic fields or spin orbit interactions which couple only to charged particles. For neutral ultracold atoms, synthetic magnetic fields have been created which are strong enough to realize the Harper-Hofstadter model. Despite many proposals and major experimental efforts, so far it has not been possible to prepare the ground state of this system. Here we report the observation of Bose-Einstein condensation for the Harper-Hofstadter Hamiltonian with one-half flux quantum per lattice unit cell. The diffraction pattern of the superfluid state directly shows the momentum distribution on the wavefuction, which is gauge-dependent. It reveals both the reduced symmetry of the vector potential and the twofold degeneracy of the ground state. We explore an adiabatic many-body state preparation protocol via the Mott insulating phase and observe the superfluid ground state in a three-dimensional lattice with strong interactions.Comment: 6 pages, 5 figures. Supplement: 6 pages, 4 figure