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A highly purified cytochromeb6 fcomplex from the cyanobacteriumSynechocystissp. PCC 6803 selectively binds one chlorophyll a and one carotenoid in analogy to the recent published structure from two otherb6 fcomplexes. The unknown function of these pigments was elucidated by spectroscopy and site-directed mutagenesis. Low-temperature redox difference spectroscopy showed red shifts in the chlorophyll and carotenoid spectra upon reduction of cytochromeb6, which indicates coupling of these pigments with the heme groups and thereby with the electron transport. This is supported by the correlated kinetics of these redox reactions and also by the distinct orientation of the chlorophyll molecule with respect to the heme cofactors as shown by linear dichroism spectroscopy. The specific role of the carotenoid echinenone for the cytochromeb6 fcomplex ofSynechocystis6803 was elucidated by a mutant lacking the last step of echinenone biosynthesis. The isolated mutant complex preferentially contained a carotenoid with 0, 1 or 2 hydroxyl groups (most likely 9-cisisomers ofβ-carotene, a monohydroxy carotenoid and zeaxanthin, respectively) instead. This indicates a substantial role of the carotenoid– possibly for strucure and assembly– and a specificity of its binding site which is different from those in most other oxygenic photosynthetic organisms. In summary, both pigments are probably involved in the structure, but may also contribute to the dynamics of the cytochromeb6 fcomplex. [ABSTRACT FROM AUTHOR]

Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula. Emission lines are detected from the PDR; modeling their kinematics and excitation allowed us to constrain the physical conditions within the gas. We quantified the mass-loss rate induced by the FUV irradiation and found that it is sufficient to remove gas from the disk in less than a million years. This is rapid enough to affect giant planet formation in the disk.

Photochemistry in H 2 O:NH 3 :CO 2 cosmic ice analogues was studied at temperatures of 75, 120, and 150 K, relevant to hot cores and warmer regions in protostellar envelopes and planet-forming disks. A combination of two triggers of surface chemistry in cosmic ice analogues, heat and UV irradiation, compared to using either just heat or UV irradiation, leads to a larger variety and an increased production of complex organic molecules, including potential precursors of prebiotic molecules. In addition to complex organic molecules detected in previous studies of H 2 O:NH 3 :CO 2 ices, ammonium carbamate, carbamic acid, ammonium formate and formamide, we detected acetaldehyde, urea, and, tentatively, glycine, the simplest amino acid. Water ice hampers reactions at low temperature (75 K) but allows the parent molecules, CO 2 and NH 3 , to stay in the solid state and react at higher temperatures (120 and 150 K, above their desorption temperatures). The experiments were performed on the surface of KBr substrates and amorphous silicate grains, analogs of cosmic silicate dust. The production of complex molecules on the silicate surface is decreased compared to KBr. This result suggests that the larger surface area and/or surface properties of the silicate grains play a role in controlling the chemistry, preventing it taking place to the same extent as on the flat KBr substrate. This is further evidence of the fact that cosmic dust grains play an important role in the chemistry taking place on their surface.

Background: In 2011, the national German Medical Association (Bundesärztekammer) published guidelines for a slim-lined training program in general practice (Quereinstieg) for qualified medical specialists in other fields (e. g., surgeons, internists or anesthesiologists). This step is part of a strategy to prevent further shortages of general practitioners in Germany. In the state of Baden-Wuerttemberg, qualified medical specialists are allowed to complete their general practice training in approximately two years instead of five. The aim of this study was to understand the reasons of specialists for changing to a career in general practice., Methods: The postgraduate training program Verbundweiterbildung plus Baden-Württemberg had 597 trainees at the time of the study in December 2015. Previously qualified specialists in another medical discipline were identified and invited to participate in this study. Qualitative data was gathered using semi-structured interviews with content analysis of the interviews performed by three independent members of the research team., Results: In total, 36 out of 597 trainees were identified as previously qualified specialists in another medical discipline. All 36 were invited to take part and 15 agreed to participate in this study. Overall, 15 interviews were performed, with a mean time of 24.19minutes. Participants with a median age of 40 years (33-59 years) - mainly anesthesiologists (n=7), surgeons (n=3) and internists (n=3) - presented with an average of 6.5 years of professional experience in their specialty. First, the participants' motivation to switch career arose from the wish to intensify the quality of patient contacts with a holistic approach including family and social background and from the infinite variety of general practice. Another reason given for a career change was self-employment opportunities. Finally, feelings of frustration over poor working conditions in hospitals resulted in a job search elsewhere in medicine, taking account of the challenges of ageing and family life. A major finding was that without the slim-lined program, the majority of participants would not have changed their career., Discussion: The slim-lined training program in general practice attracts experienced medical doctors. Specialists decide to change career because of the particular ways of working in general practice and with the intention to improve their daily work as a physician, either to improve individual working conditions and/or to improve their individual curative work profile. In addition, specialists are attracted by the concept of self-employment in general practice. Therefore, appreciation of the specific ways of working in general practice as well as management skills are most important during the reduced 2-year training. Further studies should investigate if facilitating a career switch to general practice is a good way to improve the shortage of general practitioners., (Copyright © 2016. Published by Elsevier GmbH.)

Introduction: Implementation research deals with the question of how to ensure that evidence-based knowledge is put into practice. One approach is the development of "tailored interventions (TI)". These are designed to address previously identified barriers and enablers. A common definition or methodological concept for TI has not yet been established. In this paper, a concept for TI is introduced. We describe the stepwise development of an implementation intervention for GP settings where recommendations based on current evidence are provided for the treatment of multimorbid patients receiving polypharmacy. Each step will be explained and illustrated by original data., Methods/results: A stepwise approach was used to develop a TI: problem analysis, identification and prioritisation of determinants, identification and prioritisation of strategies and the design of a complex intervention and its underlying logic model., Discussion: The stepwise exemplary description of this tailoring strategy may support other researchers in this field when designing a TI., (Copyright © 2013. Published by Elsevier GmbH.)