TY - JOUR A1 - Acharya, B. S. A1 - Aramo, C. A1 - Babic, A. A1 - Barrio, J. A. A1 - Baushev, Anton N. A1 - Tjus, J. Becker A1 - Berge, David A1 - Bohacova, M. A1 - Bonardi, A. A1 - Brown, A. A1 - Bugaev, V. A1 - Bulik, Tomasz A1 - Burton, M. A1 - Busetto, G. A1 - Caraveo, P. A. A1 - Carosi, R. A1 - Carr, John A1 - Chadwick, Paula M. A1 - Chudoba, J. A1 - Conforti, V. A1 - Connaughton, V. A1 - Contreras, J. L. A1 - Cotter, G. A1 - Dazzi, F. A1 - De Franco, A. A1 - de la Calle, I. A1 - Lopez, R. de los Reyes A1 - De Lotto, B. A1 - De Palma, F. A1 - Di Girolamo, T. A1 - Di Giulio, C. A1 - Di Pierro, F. A1 - Dournaux, J. -L. A1 - Dwarkadas, Vikram V. A1 - Ebr, J. A1 - Egberts, Kathrin A1 - Fesquet, M. A1 - Fleischhack, H. A1 - Font, L. A1 - Fontaine, G. A1 - Foerster, A. A1 - Füßling, Matthias A1 - Garcia, B. A1 - Lopez, R. Garcia A1 - Garczarczyk, M. A1 - Gargano, F. A1 - Garrido, D. A1 - Gaug, M. A1 - Giglietto, N. A1 - Giordano, F. A1 - Giuliani, A. A1 - Godinovic, N. A1 - Gonzalez, M. M. A1 - Grabarczyk, T. A1 - Hassan, T. A1 - Hoerandel, J. A1 - Hrabovsky, M. A1 - Hrupec, D. A1 - Humensky, T. B. A1 - Huovelin, J. A1 - Jamrozy, M. A1 - Janecek, P. A1 - Kaaret, P. E. A1 - Katz, U. A1 - Kaufmann, S. A1 - Khelifi, B. A1 - Kluzniak, W. A1 - Kocot, J. A1 - Komin, N. A1 - Kubo, H. A1 - Kushida, J. A1 - Lamanna, G. A1 - Lee, W. H. A1 - Lenain, J. -P. A1 - Lohse, T. A1 - Lombardi, S. A1 - Lopez-Coto, R. A1 - Lopez-Oramas, A. A1 - Lucarelli, F. A1 - Maccarone, M. C. A1 - Maier, G. A1 - Majumdar, P. A1 - Malaguti, G. A1 - Mandat, D. A1 - Mazziotta, Mario Nicola A1 - Meagher, K. A1 - Mirabal, N. A1 - Morselli, A. A1 - Moulin, Emmanuel A1 - Niemiec, J. A1 - Nievas, M. A1 - Nishijima, K. A1 - Nosek, D. A1 - Nunio, F. A1 - Ohishi, M. A1 - Ohm, S. A1 - Ong, R. A. A1 - Orito, R. A1 - Otte, N. A1 - Palatka, M. A1 - Pareschi, G. A1 - Pech, M. A1 - Persic, M. A1 - Pohl, Manuela A1 - Prouza, M. A1 - Quirrenbach, A. A1 - Raino, S. A1 - Fernandez, G. Rodriguez A1 - Romano, Patrizia A1 - Rovero, A. C. A1 - Rudak, B. A1 - Schovanek, P. A1 - Shayduk, M. A1 - Siejkowski, H. A1 - Sillanpaa, A. A1 - Stefanik, S. A1 - Stolarczyk, T. A1 - Szanecki, M. A1 - Szepieniec, T. A1 - Tejedor, L. A. A1 - Telezhinsky, Igor O. A1 - Teshima, M. A1 - Tibaldo, L. A1 - Tibolla, O. A1 - Tovmassian, G. A1 - Travnicek, P. A1 - Trzeciak, M. A1 - Vallania, P. A1 - van Eldik, C. A1 - Vercellone, S. A1 - Vigorito, C. A1 - Wagner, S. J. A1 - Wakely, S. P. A1 - Weinstein, A. A1 - Wierzcholska, A. A1 - Wilhelm, Alina A1 - Wojcik, P. A1 - Yoshikoshi, T. T1 - The Cherenkov Telescope Array potential for the study of young supernova remnants JF - Astroparticle physics N2 - Supernova remnants (SNRs) are among the most important targets for gamma-ray observatories. Being prominent non-thermal sources, they are very likely responsible for the acceleration of the bulk of Galactic cosmic rays (CRS). To firmly establish the SNR paradigm for the origin of cosmic rays, it should be confirmed that protons are indeed accelerated in, and released from, SNRs with the appropriate flux and spectrum. This can be done by detailed theoretical models which account for microphysics of acceleration and various radiation processes of hadrons and leptons. The current generation of Cherenkov telescopes has insufficient sensitivity to constrain theoretical models. A new facility, the Cherenkov Telescope Array (CTA), will have superior capabilities and may finally resolve this long standing issue of high-energy astrophysics. We want to assess the capabilities of CTA to reveal the physics of various types of SNRs in the initial 2000 years of their evolution. During this time, the efficiency to accelerate cosmic rays is highest. We perform time-dependent simulations of the hydrodynamics, the magnetic fields, the cosmic-ray acceleration, and the non-thermal emission for type Ia, Ic and IIP SNRs. We calculate the CTA response to the y-ray emission from these SNRs for various ages and distances, and we perform a realistic analysis of the simulated data. We derive distance limits for the detectability and resolvability of these SNR types at several ages. We test the ability of CTA to reconstruct their morphological and spectral parameters as a function of their distance. Finally, we estimate how well CTA data will constrain the theoretical models. (C) 2014 Elsevier B.V. All rights reserved. KW - Acceleration of particles KW - Gamma rays: General KW - ISM: Supernova remnants KW - Radiation mechanisms: Non-termal Y1 - 2015 U6 - https://doi.org/10.1016/j.astropartphys.2014.08.005 SN - 0927-6505 SN - 1873-2852 VL - 62 SP - 152 EP - 164 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Beta, Carsten A1 - Bodenschatz, Eberhard T1 - Microfluidic tools for quantitative studies of eukaryotic chemotaxis JF - European journal of cell biology N2 - Over the past decade, microfluidic techniques have been established as a versatile platform to perform live cell experiments under well-controlled conditions. To investigate the directional responses of cells, stable concentration profiles of chemotactic factors can be generated in microfluidic gradient mixers that provide a high degree of spatial control. However, the times for built-up and switching of gradient profiles are in general too slow to resolve the intracellular protein translocation events of directional sensing of eukaryotes. Here, we review an example of a conventional microfluidic gradient mixer as well as the novel flow photolysis technique that achieves an increased temporal resolution by combining the photo-activation of caged compounds with the advantages of microfluidic chambers. KW - Eukaryotic chemotaxis KW - Dictyostelium discoideum KW - Microfluidics KW - Caged compounds KW - Numerical simulations Y1 - 2011 U6 - https://doi.org/10.1016/j.ejcb.2011.05.006 SN - 0171-9335 VL - 90 IS - 10 SP - 811 EP - 816 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Borde, Ron A1 - Smith, Jordan J. A1 - Sutherland, Rachel A1 - Nathan, Nicole A1 - Lubans, David Revalds T1 - Methodological considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis JF - Obesity reviews : an official journal of the International Association for the Study of Obesity N2 - Objective: The aims of this systematic review and meta-analysis are (i) to determine the impact of school-based interventions on objectively measured physical activity among adolescents and (ii) to examine accelerometer methods and decision rule reporting in previous interventions. Methods: A systematic search was performed to identify randomized controlled trials targeting adolescents (age: >= 10 years), conducted in the school setting, and reporting objectively measured physical activity. Random effects meta-analyses were conducted to determine the pooled effects of previous interventions on total and moderate-to-vigorous physical activity. Potential moderators of intervention effects were also explored. Results: Thirteen articles met the inclusion criteria, and twelve were included in the meta-analysis. The pooled effects were small and non-significant for both total physical activity (standardized mean difference = 0.02 [95% confidence interval = -0.13 to 0.18]) and moderate-to-vigorous physical activity (standardized mean difference = 0.24 [95% confidence interval = -0.08 to 0.56]). Sample age and accelerometer compliance were significant moderators for total physical activity, with a younger sample and higher compliance associated with larger effects. Conclusion: Previous school-based physical activity interventions targeting adolescents have been largely unsuccessful, particularly for older adolescents. There is a need for more high-quality research using objective monitoring in this population. Future interventions should comply with best-practice recommendations regarding physical activity monitoring protocols. KW - Accelerometer KW - physical activity KW - school KW - youth Y1 - 2017 U6 - https://doi.org/10.1111/obr.12517 SN - 1467-7881 SN - 1467-789X VL - 18 SP - 476 EP - 490 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Bulla, Mattia A1 - Coughlin, Michael W. A1 - Dhawan, Suhail A1 - Dietrich, Tim T1 - Multi-messenger constraints on the Hubble constant through combination of gravitational waves, gamma-ray bursts and kilonovae from neutron star mergers JF - Universe : open access journal N2 - The simultaneous detection of gravitational waves and light from the binary neutron star merger GW170817 led to independent measurements of distance and redshift, providing a direct estimate of the Hubble constant H-0 that does not rely on a cosmic distance ladder, nor assumes a specific cosmological model. By using gravitational waves as "standard sirens", this approach holds promise to arbitrate the existing tension between the H-0 value inferred from the cosmic microwave background and those obtained from local measurements. However, the known degeneracy in the gravitational-wave analysis between distance and inclination of the source led to a H-0 value from GW170817 that was not precise enough to resolve the existing tension. In this review, we summarize recent works exploiting the viewing-angle dependence of the electromagnetic signal, namely the associated short gamma-ray burst and kilonova, to constrain the system inclination and improve on H-0. We outline the key ingredients of the different methods, summarize the results obtained in the aftermath of GW170817 and discuss the possible systematics introduced by each of these methods. KW - gravitational waves KW - stars: neutron KW - stars: binaries KW - cosmology: cosmological parameters KW - cosmology: distance scale KW - cosmology: cosmic background radiation Y1 - 2022 U6 - https://doi.org/10.3390/universe8050289 SN - 2218-1997 VL - 8 IS - 5 PB - MDPI CY - Basel ER - TY - JOUR A1 - Bykov, Andrei A1 - Gehrels, Neil A1 - Krawczynski, Henric A1 - Lemoine, Martin A1 - Pelletier, Guy A1 - Pohl, Martin T1 - Particle acceleration in relativistic outflows JF - Space science reviews N2 - In this review we confront the current theoretical understanding of particle acceleration at relativistic outflows with recent observational results on various source classes thought to involve such outflows, e.g. gamma-ray bursts, active galactic nuclei, and pulsar wind nebulae. We highlight the possible contributions of these sources to ultra-high-energy cosmic rays. KW - Cosmic rays KW - Particle acceleration KW - Shocks Y1 - 2012 U6 - https://doi.org/10.1007/s11214-012-9896-y SN - 0038-6308 VL - 173 IS - 1-4 SP - 309 EP - 339 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Cardinaletti, Ilaria A1 - Kesters, Jurgen A1 - Bertho, Sabine A1 - Conings, Bert A1 - Piersimoni, Fortunato A1 - Lutsen, Laurence A1 - Nesladek, Milos A1 - Van Mele, Bruno A1 - Van Assche, Guy A1 - Vandewal, Koen A1 - Salleo, Alberto A1 - Vanderzande, Dirk A1 - Maes, Wouter A1 - Manca, Jean V. T1 - Toward bulk heterojunction polymer solar cells with thermally stable active layer morphology JF - Journal of photonics for energy N2 - When state-of-the-art bulk heterojunction organic solar cells with ideal morphology are exposed to prolonged storage or operation at elevated temperatures, a thermally induced disruption of the active layer blend can occur, in the form of a separation of donor and acceptor domains, leading to diminished photovoltaic performance. Toward the long-term use of organic solar cells in real-life conditions, an important challenge is, therefore, the development of devices with a thermally stable active layer morphology. Several routes are being explored, ranging from the use of high glass transition temperature, cross-linkable and/or side-chain functionalized donor and acceptor materials, to light-induced dimerization of the fullerene acceptor. A better fundamental understanding of the nature and underlying mechanisms of the phase separation and stabilization effects has been obtained through a variety of analytical, thermal analysis, and electro-optical techniques. Accelerated aging systems have been used to study the degradation kinetics of bulk heterojunction solar cells in situ at various temperatures to obtain aging models predicting solar cell lifetime. The following contribution gives an overview of the current insights regarding the intrinsic thermally induced aging effects and the proposed solutions, illustrated by examples of our own research groups. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. KW - organic photovoltaics KW - bulk heterojunction KW - thermal stability KW - phase separation KW - lifetime Y1 - 2014 U6 - https://doi.org/10.1117/1.JPE.4.040997 SN - 1947-7988 VL - 4 PB - SPIE CY - Bellingham ER - TY - JOUR A1 - Dai, Xiaolin A1 - Böker, Alexander A1 - Glebe, Ulrich T1 - Broadening the scope of sortagging JF - RSC Advances N2 - Sortases are enzymes occurring in the cell wall of Gram-positive bacteria. Sortase A (SrtA), the best studied sortase class, plays a key role in anchoring surface proteins with the recognition sequence LPXTG covalently to oligoglycine units of the bacterial cell wall. This unique transpeptidase activity renders SrtA attractive for various purposes and motivated researchers to study multiple in vivo and in vitro ligations in the last decades. This ligation technique is known as sortase-mediated ligation (SML) or sortagging and developed to a frequently used method in basic research. The advantages are manifold: extremely high substrate specificity, simple access to substrates and enzyme, robust nature and easy handling of sortase A. In addition to the ligation of two proteins or peptides, early studies already included at least one artificial (peptide equipped) substrate into sortagging reactions - which demonstrates the versatility and broad applicability of SML. Thus, SML is not only a biology-related technique, but has found prominence as a major interdisciplinary research tool. In this review, we provide an overview about the use of sortase A in interdisciplinary research, mainly for protein modification, synthesis of protein-polymer conjugates and immobilization of proteins on surfaces. Y1 - 2019 U6 - https://doi.org/10.1039/c8ra06705h SN - 2046-2069 VL - 9 IS - 9 SP - 4700 EP - 4721 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Filacchione, Gianrico A1 - Groussin, Olivier A1 - Herny, Clemence A1 - Kappel, David A1 - Mottola, Stefano A1 - Oklay, Nilda A1 - Pommerol, Antoine A1 - Wright, Ian A1 - Yoldi, Zurine A1 - Ciarniello, Mauro A1 - Moroz, Lyuba A1 - Raponi, Andrea T1 - Comet 67P/CG Nucleus Composition and Comparison to Other Comets JF - Space science reviews N2 - We review our current knowledge of comet 67P/Churyumov–Gerasimenko nucleus composition as inferred from measurements made by remote sensing and in-situ instruments aboard Rosetta orbiter and Philae lander. Spectrophotometric properties (albedos, color indexes and Hapke parameters) of 67P/CG derived by Rosetta are discussed in the context of other comets previously explored by space missions. Composed of an assemblage made of ices, organic materials and minerals, cometary nuclei exhibit very dark and red surfaces which can be described by means of spectrophotometric quantities and reproduced with laboratory measurements. The presence of surface water and carbon dioxide ices was found by Rosetta to occur at localized sites where the activity driven by solar input, gaseous condensation or exposure of pristine inner layers can maintain these species on the surface. Apart from these specific areas, 67P/CG’s surface appears remarkably uniform in composition with a predominance of organic materials and minerals. The organic compounds contain abundant hydroxyl group and a refractory macromolecular material bearing aliphatic and aromatic hydrocarbons. The mineral components are compatible with a mixture of silicates and fine-grained opaques, including Fe-sulfides, like troilite and pyrrhotite, and ammoniated salts. In the vicinity of the perihelion several active phenomena, including the erosion of surface layers, the localized activity in cliffs, fractures and pits, the collapse of overhangs and walls, the transfer and redeposition of dust, cause the evolution of the different regions of the nucleus by inducing color, composition and texture changes. KW - Comets KW - Composition KW - Ices KW - Organic matter KW - Minerals Y1 - 2019 U6 - https://doi.org/10.1007/s11214-019-0580-3 SN - 0038-6308 SN - 1572-9672 VL - 215 IS - 19 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Gerhard, Reimund T1 - Katzir, S., The beginnings of piezoelectricity: a study in mundane physics; Dordrecht, Springer, 2006 BT - The beginnings of piezoelectricity: a study in mundane physics Y1 - 2007 ER - TY - JOUR A1 - Gessner, Oliver A1 - Gühr, Markus T1 - Monitoring Ultrafast Chemical Dynamics by Time-Domain X-ray Photo- and Auger-Electron Spectroscopy JF - Accounts of chemical research N2 - The directed flow of charge and energy is at the heart of all chemical processes. Extraordinary efforts are underway to monitor and understand the concerted motion of electrons and nuclei with ever increasing spatial and temporal sensitivity. The element specificity, chemical sensitivity, and temporal resolution of ultrafast X-ray spectroscopy techniques hold great promise to provide new insight into the fundamental interactions underlying chemical dynamics in systems ranging from isolated molecules to application-like devices. Here, we focus on the potential of ultrafast X-ray spectroscopy techniques based on the detection of photo- and Auger electrons to provide new fundamental insight into photochemical processes of systems with various degrees of complexity. Isolated nucleobases provide an excellent testing ground for our most fundamental understanding of intramolecular coupling between electrons and nuclei beyond the traditionally applied Born-Oppenheimer approximation. Ultrafast electronic relaxation dynamics enabled by the breakdown of this approximation is the major component of the nucleobase photoprotection mechanisms. Transient X-ray induced Auger electron spectroscopy on photoexcited thymine molecules provides atomic-site specific details of the extremely efficient coupling that converts potentially bond changing ultraviolet photon energy into benign heat. In particular, the time-dependent spectral shift of a specific Auger band is sensitive to the length of a single bond within the molecule. The X-ray induced Auger transients show evidence for an electronic transition out of the initially excited state within only similar to 200 fs in contrast to theoretically predicted picosecond population trapping behind a reaction barrier. Photoinduced charge transfer dynamics between transition metal complexes and semiconductor nanostructures are of central importance for many emerging energy and climate relevant technologies. Numerous demonstrations of photovoltaic and photocatalytic activity have been performed based on the combination of strong light absorption in dye molecules with charge separation and transport in adjacent semiconductor nanostructures. However, a fundamental understanding of the enabling and limiting dynamics on critical atomic length- and time scales is often still lacking. Femtosecond time-resolved X-ray photoelectron spectroscopy is employed to gain a better understanding of a short-lived intermediate that may be linked to the unexpectedly limited performance of ZnO based dye-sensitized solar cells by delaying the generation of free charge carriers. The transient spectra strongly suggest that photoexcited dye molecules attached to ZnO nanocrystals inject their charges into the substrate within less than 1 ps but the electrons are then temporarily trapped at the surface of the semiconductor in direct vicinity of the injecting molecules. The experiments are extended to monitor the electronic response of the semiconductor substrate to the collective injection from a monolayer of dye molecules and the subsequent electron-ion recombination dynamics. The results indicate some qualitative similarities but quantitative differences between the recombination dynamics at molecule-semiconductor interfaces and previously studied bulk-surface electron-hole recombination dynamics in photoexcited semiconductors. Y1 - 2016 U6 - https://doi.org/10.1021/acs.accounts.5b00361 SN - 0001-4842 SN - 1520-4898 VL - 49 SP - 138 EP - 145 PB - American Chemical Society CY - Washington ER -