Fusion mechanism in fullerene-fullerene collisions -- The deciding role of giant oblate-prolate motion

We provide answers to long-lasting questions in the puzzling behavior of fullerene-fullerene fusion: Why are the fusion barriers so exceptionally high and the fusion cross sections so extremely small? An ab initio nonadiabatic quantum molecular dynamics (NA-QMD) analysis of C$_{60}$+C$_{60}$ collisions reveals that the dominant excitation of an exceptionally "giant" oblate-prolate H$_g(1)$ mode plays the key role in answering both questions. From these microscopic calculations, a macroscopic collision model is derived, which reproduces the NA-QMD results. Moreover, it predicts analytically fusion barriers for different fullerene-fullerene combinations in excellent agreement with experiments

Video laryngoscopy versus direct laryngoscopy for endotracheal intubation in the emergency department and intensive care unit

Background: Endotracheal intubation is a foundational skill of emergency and critical care clinicians. Direct laryngoscopy (DL) has long been the go-to method of intubation, but difficult airway characteristics can hinder clinicians\u27 ability to intubate on their first attempt. Video laryngoscopy (VL) has been suggested as a tool to improve airway management in patients with problematic airway characteristics. However, current data comparing DL to VL has been predominately observational and has produced inconsistent findings. Objective: The study\u27s objective was to investigate if there is evidence to suggest that VL results in more first-pass intubation success and reduced complications compared to DL in patients needing emergent intubation. Methods: A systematic review of EBSCO and PubMed databases was performed, examining for studies that compared VL and DL in the emergency department (ED) and intensive care unit (ICU). Relevant articles were then independently reviewed and filtered against various inclusion and exclusion criteria. The primary outcome was the overall rate of first-pass intubation success, with additional analyses based on clinician experience and type of VL used. The secondary outcome was the incidence of complication rates with either device. Results: A total of 21,788 intubations were attempted across 12 studies with either DL (n = 12,527) or VL (n = 9,261). Data was presented as [odds ratio (95% confidence intervals); P values]. Overall rate of first-pass intubation was 80% and 75% for the VL and DL groups, respectfully [OR=1.35 (1.26–1.45); P\u3c0.0001]. Compared to DL, VL had higher rates of first-pass success amongst less experienced physicians [80.46% vs. 71.66%; OR=1.63 (1.45–1.83); P\u3c0.0001] and a lower incidence of esophageal intubations [1.27% vs. 6.02%; OR=4.93 (3.63–6.70); P\u3c0.0001]. Amongst various VL devices, the CMAC VL led to more first-pass success when compared to the GVL [83.89% vs. 78.18%; OR=1.46 (1.25–1.69); P\u3c0.0001]. DL was associated with greater first-pass success amongst experienced clinicians when compared to VL [81.88% vs 72.84%; OR=0.59 (0.52–0.68); P\u3c0.0001] and decreased incidence of hypoxemia [12.91% vs. 16.88%; OR=1.37 (1.19–1.57); P\u3c0.0001]. Complications such as airway trauma, hypotension, and aspiration were unchanged between the two groups. Conclusion: The use of VL in patients undergoing emergent intubation was associated with a greater overall first-pass success rate when compared to DL, while also increasing first-pass success in inexperienced physicians and reducing the incidence of esophageal intubations. However, VL was associated with decreased first-pass success in experienced physicians and a greater incidence of hypoxemia. Further randomized controlled trials must be conducted to investigate the utility of VL over DL in the ED and ICU

Neue Sprachen lehren und lernen : Fremdsprachenunterricht in der Weiterbildung

Neue wie erfahrene Lehrende in der Erwachsenenbildung stehen vor der ständigen Herausforderung, ihr Wissen über den Fremdsprachenunterricht zu aktualisieren: Wie wirken sich neuere Entwicklungen in der Linguistik oder in der Lerntheorie auf die Didaktik und Methodik des Fremdsprachenunterrichts mit Erwachsenen aus? Die Beiträge dieses Bandes zeigen nicht nur, 'wie' man unterrichtet, sondern sie widmen sich auch den 'Warum'-Fragen

Orientation dependence of energy absorption and relaxation dynamics of C60\text{C}_{60} in fs-laser pulses: How round is C60\text{C}_{60}?

By means of non-adiabatic quantum molecular dynamics it is shown, that the amount of energy deposited into $\text{C}_{60}$ by a short laser field strongly depends on the molecular orientation with respect to the laser polarization direction. In consequence, subsequent electron-vibration coupling leads to different nuclear relaxation mechanisms with mainly three pathways: (1) excitation of giant $\text{A}_g(1)$ modes ("breathing"), (2) formation of deformed cage-like complexes ("isomers"), fragmentation predominantly into two large pieces ("fission"). The results are in accord with and explain nicely already existing experimental data. Future experiments are proposed to confirm the detailed predictions.Comment: 5 pages, 3 figure

Ab-initio molecular dynamics studies of laser- and collision-induced processes in multielectron diatomics, organic molecules and fullerenes

This work presents applications of an ab-initio molecular dynamics method, the so-called nonadiabatic quantum molecular dynamics (NA-QMD), for various molecular systems with many electronic and nuclear degrees of freedom. Thereby, the nuclei will be treated classically and the electrons with time-dependent density functional theory (TD-DFT) in basis expansion. Depending on the actual system and physical process, well suited basis sets for the Kohn-Sham orbitals has to be chosen. For the ionization process a novel absorber acting in the energy space as well as additional basis functions will be used depending on the laser frequency. In the first part of the applications, a large variety of different laser-induced molecular processes will be investigated. This concerns, the orientation dependence of the ionization of multielectronic diatomics (N2, O2), the isomerization of organic molecules (N2H2) and the giant excitation of the breathing mode in fullerenes (C60). In the second part, fullerene-fullerene collisions are investigated, for the first time in the whole range of relevant impact velocities concerning the vibrational and electronic energy transfer (\"stopping~power\"). For low energetic (adiabatic) collisions, it is surprisingly found, that a two-dimensional, phenomenological collision model can reproduce (even quantitatively) the basic features of fusion and scattering observed in the fully microscopic calculations as well as in the experiment. For high energetic (nonadiabatic) collisions, the electronic and vibrational excitation regimes are predicted, leading to multifragmentation up to complete atomization