TY - JOUR A1 - Nöchel, Ulrich A1 - Reddy, Chaganti Srinivasa A1 - Wang, Ke A1 - Cui, Jing A1 - Zizak, Ivo A1 - Behl, Marc A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Nanostructural changes in crystallizable controlling units determine the temperature-memory of polymers JF - Journal of materials chemistry : A, Materials for energy and sustainability N2 - Temperature-memory polymers remember the temperature, where they were deformed recently, enabled by broad thermal transitions. In this study, we explored a series of crosslinked poly[ethylene-co-(vinyl acetate)] networks (cPEVAs) comprising crystallizable polyethylene (PE) controlling units exhibiting a pronounced temperature-memory effect (TME) between 16 and 99 degrees C related to a broad melting transition (similar to 100 degrees C). The nanostructural changes in such cPEVAs during programming and activation of the TME were analyzed via in situ X-ray scattering and specific annealing experiments. Different contributions to the mechanism of memorizing high or low deformation temperatures (T-deform) were observed in cPEVA, which can be associated to the average PE crystal sizes. At high deformation temperatures (>50 degrees C), newly formed PE crystals, which are established during cooling when fixing the temporary shape, dominated the TME mechanism. In contrast, at low T-deform (<50 degrees C), corresponding to a cold drawing scenario, the deformation led preferably to a disruption of existing large crystals into smaller ones, which then fix the temporary shape upon cooling. The observed mechanism of memorizing a deformation temperature might enable the prediction of the TME behavior and the knowledge based design of other TMPs with crystallizable controlling units. Y1 - 2015 U6 - https://doi.org/10.1039/c4ta06586g SN - 2050-7488 SN - 2050-7496 VL - 3 IS - 16 SP - 8284 EP - 8293 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Mazurek-Budzyńska, Magdalena A1 - Behl, Marc A1 - Razzaq, Muhammad Yasar A1 - Nöchel, Ulrich A1 - Rokicki, Gabriel A1 - Lendlein, Andreas T1 - Hydrolytic stability of aliphatic poly(carbonate-urea-urethane)s: Influence of hydrocarbon chain length in soft segment JF - Polymer Degradation and Stability N2 - Poly(carbonate-urethane)s (PCUs) exhibit improved resistance to hydrolytic degradation and in vivo stress cracking compared to poly(ester-urethane)s and their degradation leads to lower inflammation of the surrounding tissues. Therefore, PCUs are promising implant materials and are considered for devices such as artificial heart or spine implants. In this work, the hydrolytic stability of different poly(carbonate-urethane-urea)s (PCUUs) was studied under variation of the length of hydrocarbon chain (6, 9, 10, and 12 methylene units) between the carbonate linkages in the precursors. PCUUs were synthesized from isophorone diisocyanate and oligo(alkylene carbonate) diols using the moisture-cure method. The changes of sample weight, thermal and mechanical properties, morphology, as well as the degradation products after immersion in a buffer solution (PBS, pH = 7.4) for up to 10 weeks at 37 degrees C were monitored and analyzed. In addition, mechanical properties after 20 weeks (in PBS, 37 degrees C) were investigated. The gel content was determined based on swelling experiments in chloroform. Based on the DSC analysis, slight increases of melting transitions of PCUUs were observed, which were attributed to structure reorganization related to annealing at 37 degrees C rather than to the degradation of the PCUU. Tensile strength after 20 weeks of all investigated samples remained in the range of 29-39 MPa, whereas the elongation at break e(m) decreased only slightly and remained in the range between 670 and 800%. Based on the characterization of degradation products after up to 10 weeks of immersion it was assessed that oligomers are mainly consisting of hard segments containing urea linkages, which could be assigned to hindered-urea dissociation mechanism. The investigations confirmed good resistance of PCUUs to hydrolysis. Only minor changes in the crystallinity, as well as thermal and mechanical properties were observed and depended on hydrocarbon chain length in soft segment of PCUUs. (C) 2019 Published by Elsevier Ltd. KW - Poly(carbonate-urea-urethane)s KW - Hydrolytic stability KW - Degradation Y1 - 2019 SN - 0141-3910 SN - 1873-2321 VL - 161 SP - 283 EP - 297 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Yan, Wan A1 - Rudolph, Tobias A1 - Nöchel, Ulrich A1 - Gould, Oliver E. C. A1 - Behl, Marc A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Reversible actuation of thermoplastic multiblock copolymers with overlapping thermal transitions of crystalline and glassy domains JF - Macromolecules : a publication of the American Chemical Society N2 - Polymeric materials possessing specific features like programmability, high deformability, and easy processability are highly desirable for creating modern actuating systems. In this study, thermoplastic shape-memory polymer actuators obtained by combining crystallizable poly(epsilon-caprolactone) (PCL) and poly(3S-isobutylmorpholin-2,5-dione) (PIBMD) segments in multiblock copolymers are described. We designed these materials according to our hypothesis that the confinement of glassy PIBMD domains present at the upper actuation temperature contribute to the stability of the actuator skeleton, especially at large programming strains. The copolymers have a phase-segregated morphology, indicated by the well-separated melting and glass transition temperatures for PIBMD and PCL, but possess a partially overlapping T-m of PCL and T-g of PIBMD in the temperature interval from 40 to 60 degrees C. Crystalline PIBMD hard domains act as strong physical netpoints in the PIBMD-PCL bulk material enabling high deformability (up to 2000%) and good elastic recoverability (up to 80% at 50 degrees C above T-m,T-PCL). In the programmed thermoplastic actuators a high content of crystallizable PCL actuation domains ensures pronounced thermoreversible shape changes upon repetitive cooling and heating. The programmed actuator skeleton, composed of PCL crystals present at the upper actuation temperature T-high and the remaining glassy PIBMD domains, enabled oriented crystallization upon cooling. The actuation performance of PIBMD-PCL could be tailored by balancing the interplay between actuation and skeleton, but also by varying the quantity of crystalline PIBMD hard domains via the copolymer composition, the applied programming strain, and the choice of T-high. The actuator with 17 mol% PIBMD showed the highest reversible elongation of 11.4% when programmed to a strain of 900% at 50 degrees C. It is anticipated that the presented thermoplastic actuator materials can be applied as modern compression textiles. Y1 - 2018 U6 - https://doi.org/10.1021/acs.macromol.8b00322 SN - 0024-9297 SN - 1520-5835 VL - 51 IS - 12 SP - 4624 EP - 4632 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Farhan, Muhammad A1 - Chaudhary, Deeptangshu A1 - Nöchel, Ulrich A1 - Behl, Marc A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Electrical actuation of coated and composite fibers based on poly[ethylene-co-(vinyl acetate)] JF - Macromolecular materials and engineering N2 - Robots are typically controlled by electrical signals. Resistive heating is an option to electrically trigger actuation in thermosensitive polymer systems. In this study electrically triggerable poly[ethylene-co-(vinyl acetate)] (PEVA)-based fiber actuators are realized as composite fibers as well as polymer fibers with conductive coatings. In the coated fibers, the core consists of crosslinked PEVA (cPEVA), while the conductive coating shell is achieved via a dip coating procedure with a coating thickness between 10 and 140 mu m. The conductivity of coated fibers sigma = 300-550 S m(-1) is much higher than that of the composite fibers sigma = 5.5 S m(-1). A voltage (U) of 110 V is required to heat 30 cm of coated fiber to a targeted temperature of approximate to 65 degrees C for switching in less than a minute. Cyclic electrical actuation investigations reveal epsilon '(rev) = 5 +/- 1% reversible change in length for coated fibers. The fabrication of such electro-conductive polymeric actuators is suitable for upscaling so that their application potential as artificial muscles can be explored in future studies. KW - artificial muscles KW - fiber actuators KW - resistive heating KW - shape‐memory polymer actuators KW - soft robotics Y1 - 2020 U6 - https://doi.org/10.1002/mame.202000579 SN - 1438-7492 SN - 1439-2054 VL - 306 IS - 2 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Yan, Wan A1 - Fang, Liang A1 - Nöchel, Ulrich A1 - Gould, Oliver E. C. A1 - Behl, Marc A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Investigating the roles of crystallizable and glassy switching segments within multiblock copolymer shape-memory materials JF - MRS Advances N2 - The variation of the molecular architecture of multiblock copolymers has enabled the introduction of functional behaviour and the control of key mechanical properties. In the current study, we explore the synergistic relationship of two structural components in a shape-memory material formed of a multiblock copolymer with crystallizable poly(epsilon-caprolactone) and crystallizable polyfoligo(3S-iso-butylmorpholine-2,5-dione) segments (PCL-PIBMD). The thermal and structural properties of PCL-PIBMD films were compared with PCI.-PU and PMMD-PU investigated by means of DSC, SAXS and WARS measurements. The shape-memory properties were quantified by cyclic, thermomechanical tensile tests, where deformation strains up to 900% were applied for programming PCL-PIBMD films at 50 degrees C. Toluene vapor treatment experiments demonstrated that the temporary shape was fixed mainly by glassy PIBMD domains at strains lower than 600% with the PCL contribution to fixation increasing to 42 +/- 2% at programming strains of 900% This study into the shape-memory mechanism of PCL-PIBMD provides insight into the structure function relation in multiblock copolymers with both crystallizable and glassy switching segments. Y1 - 2018 U6 - https://doi.org/10.1557/adv.2018.590 SN - 2059-8521 VL - 3 IS - 63 SP - 3741 EP - 3749 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Saatchi, Mersa A1 - Behl, Marc A1 - Nöchel, Ulrich A1 - Lendlein, Andreas T1 - Copolymer Networks From Oligo(epsilon-caprolactone) and n-Butyl Acrylate Enable a Reversible Bidirectional Shape-Memory Effect at Human Body Temperature JF - Macromolecular rapid communications N2 - Exploiting the tremendous potential of the recently discovered reversible bidirectional shape-memory effect (rbSME) for biomedical applications requires switching temperatures in the physiological range. The recent strategy is based on the reduction of the melting temperature range (T-m) of the actuating oligo(epsilon-caprolactone) (OCL) domains in copolymer networks from OCL and n-butyl acrylate (BA), where the reversible effect can be adjusted to the human body temperature. In addition, it is investigated whether an rbSME in the temperature range close or even above T-m,T-offset (end of the melting transition) can be obtained. Two series of networks having mixtures of OCLs reveal broad T(m)s from 2 degrees C to 50 degrees C and from -10 degrees C to 37 degrees C, respectively. In cyclic, thermomechanical experiments the rbSME can be tailored to display pronounced actuation in a temperature interval between 20 degrees C and 37 degrees C. In this way, the application spectrum of the rbSME can be extended to biomedical applications. KW - body temperature KW - broad melting temperature range KW - orientational memory KW - reversible bidirectional shape-memory polymer KW - copolymer networks Y1 - 2015 U6 - https://doi.org/10.1002/marc.201400729 SN - 1022-1336 SN - 1521-3927 VL - 36 IS - 10 SP - 880 EP - 884 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Anklam, Elke A1 - Behler, Jörg A1 - Dingermann, Theodor A1 - Elsinghorst, Paul A1 - Fischer, Jochen A1 - Esselen, Melanie A1 - Foerster, Christian A1 - Fröhlich, Daniel A1 - Goedel, Werner Andreas A1 - Gregory, Peter A1 - Grimme, Stefan A1 - Hackenberger, Christian A1 - Hansmann, Max A1 - Heppekausen, Johannes A1 - Hasenstab-Riedel, Sebastian A1 - Kirchhoff, Erhard A1 - Kratz, Karl-Ludwig A1 - Krausz, Ferenc A1 - Linker, Torsten A1 - List, Benjamin A1 - Ray, Kallol A1 - Salzer, Reiner A1 - Schubert, Ulrich A1 - Schueth, Ferdi A1 - Schwarz, Helmut A1 - Schwietzke, Uta A1 - Strey, Reinhard A1 - Stumpf, Thorsten A1 - Vaagt, Franziska A1 - Volodkin, Dmitry A1 - Wilke, Guenther A1 - Zass, Engelbert A1 - Zemb, Thomas T1 - Awards JF - Nachrichten aus der Chemie : Zeitschrift der Gesellschaft Deutscher Chemiker Y1 - 2013 U6 - https://doi.org/10.1002/nadc.201390372 SN - 1439-9598 SN - 1868-0054 VL - 61 IS - 11 SP - 1145 EP - 1148 PB - Ges. Dt. Chemiker CY - Frankfurt, Main ER - TY - JOUR A1 - Yan, Wan A1 - Fang, Liang A1 - Nöchel, Ulrich A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Influence of deformation temperature on structural variation and shape-memory effect of a thermoplastic semi-crystalline multiblock copolymer JF - eXPRESS polymer letters N2 - A multiblock copolymer termed as PCL-PIBMD, consisting of crystallizable poly(epsilon-caprolactone) (PCL) segments and crystallizable poly(3S-isobutyl-morpholine-2,5-dione) (PIBMD) segments, has been reported as a material showing a thermally-induced shape-memory effect. While PIBMD crystalline domains act as netpoints to determine the permanent shape, both PCL crystalline domains and PIBMD amorphous domains, which have similar transition temperatures (T-trans) can act as switching domains. In this work, the influence of the deformation temperature (T-deform = 50 or 20 degrees C), which was above or below T-trans, on the structural changes of PCL-PIBMD during uniaxial deformation and the shapememory properties were investigated. Furthermore, the relative contribution of crystalline PCL and PIBMD amorphous phases to the fixation of the temporary shape were distinguished by a toluene vapor treatment approach. The results indicated that at 50 degrees C, both PCL and PIBMD amorphous phases can be orientated during deformation, resulting in thermally-induced crystals of PCL domains and joint contribution to the switching domains. In contrast at 20 degrees C, the temporary shape was mainly fixed by PCL crystals generated via strain-induced crystallization. KW - biodegradable polymers KW - shape-memory polymer KW - multiblock copolymer KW - polydepsipeptide Y1 - 2015 U6 - https://doi.org/10.3144/expresspolymlett.2015.58 SN - 1788-618X VL - 9 IS - 7 SP - 624 EP - 635 PB - Budapest University of Technology and Economics, Department of Polymer Engineering CY - Budapest ER - TY - JOUR A1 - Sic, Heiko A1 - Kraus, Helene A1 - Madl, Josef A1 - Flittner, Karl-Andreas A1 - von Muenchow, Audrey Lilly A1 - Pieper, Kathrin A1 - Rizzi, Marta A1 - Kienzler, Anne-Kathrin A1 - Ayata, Korcan A1 - Rauer, Sebastian A1 - Kleuser, Burkhard A1 - Salzer, Ulrich A1 - Burger, Meike A1 - Zirlik, Katja A1 - Lougaris, Vassilios A1 - Plebani, Alessandro A1 - Roemer, Winfried A1 - Loeffler, Christoph A1 - Scaramuzza, Samantha A1 - Villa, Anna A1 - Noguchi, Emiko A1 - Grimbacher, Bodo A1 - Eibel, Hermann T1 - Sphingosine-1-phosphate receptors control B-cell migration through signaling components associated with primary immunodeficiencies, chronic lymphocytic leukemia, and multiple sclerosis JF - The journal of allergy and clinical immunology N2 - Background: Five different G protein-coupled sphingosine-1-phosphate (S1P) receptors (S1P1-S1P5) regulate a variety of physiologic and pathophysiologic processes, including lymphocyte circulation, multiple sclerosis (MS), and cancer. Although B-lymphocyte circulation plays an important role in these processes and is essential for normal immune responses, little is known about S1P receptors in human B cells. Objective: To explore their function and signaling, we studied B-cell lines and primary B cells from control subjects, patients with leukemia, patients with S1P receptor inhibitor-treated MS, and patients with primary immunodeficiencies. Methods: S1P receptor expression was analyzed by using multicolor immunofluorescence microscopy and quantitative PCR. Transwell assays were used to study cell migration. S1P receptor internalization was visualized by means of time-lapse imaging with fluorescent S1P receptor fusion proteins expressed by using lentiviral gene transfer. B-lymphocyte subsets were characterized by means of flow cytometry and immunofluorescence microscopy. Results: Showing that different B-cell populations express different combinations of S1P receptors, we found that S1P1 promotes migration, whereas S1P4 modulates and S1P2 inhibits S1P1 signals. Expression of CD69 in activated B lymphocytes and B cells from patients with chronic lymphocytic leukemia inhibited S1P-induced migration. Studying B-cell lines, normal B lymphocytes, and B cells from patients with primary immunodeficiencies, we identified Bruton tyrosine kinase, beta-arrestin 2, LPS-responsive beige-like anchor protein, dedicator of cytokinesis 8, and Wiskott-Aldrich syndrome protein as critical signaling components downstream of S1P1. Conclusion: Thus S1P receptor signaling regulates human B-cell circulation and might be a factor contributing to the pathology of MS, chronic lymphocytic leukemia, and primary immunodeficiencies. KW - Sphingosine-1-phosphate KW - B cells KW - migration KW - autoimmunity KW - circulation KW - fingolimod KW - FTY720 KW - primary immunodeficiencies Y1 - 2014 U6 - https://doi.org/10.1016/j.jaci.2014.01.037 SN - 0091-6749 SN - 1097-6825 VL - 134 IS - 2 SP - 420 EP - + PB - Elsevier CY - New York ER - TY - JOUR A1 - Fang, Liang A1 - Yan, Wan A1 - Nöchel, Ulrich A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Programming structural functions in phase-segregated polymers by implementing a defined thermomechanical history JF - Polymer : the international journal for the science and technology of polymers N2 - Unwanted shrinkage behaviors or failure in structural functions such as mechanical strength or deformability of polymeric products related to their thermomechanical history are a major challenge in production of plastics. Here, we address the question whether we can turn this challenge into an opportunity by creating defined thermomechanical histories in polymers, represented by a specific morphology and nanostructure, to equip polymeric shaped bodies with desired functions, e.g. a temperature-memory, by hot, warm or cold deformation into multiblock copolymers having two partially overlapping melting transitions. A copolyesterurethane named PDLCL, consisting of poly(epsilon-caprolactone) (PCL) and poly(omega-pentadecalactone) (PPDL) crystalline domains, exhibiting a pronounced phase-segregated morphology and partially overlapping melting transitions was selected for this study. Different types of PCL and PPDL crystals as well as distinct degrees of orientation in both amorphous and crystalline domains were obtained after deformation at 20 or 40 degrees C and to a lower extent at 60 degrees C. The generated non-isotropic structures were stable at ambient temperature and represent the different stresses stored. Stress-free heating experiments showed that the relaxation in both amorphous and crystalline phases occurred predominantly with melting of PCL crystals. When the switching temperature, which was similar to the applied deformation temperature (temperature-memory), was exceeded in stress-free heating experiments, the implemented thermomechanical history could be reversed. In contrast, during constant-strain heating to 60 degrees C the generated structural features remained almost unchanged. These findings provide insights about the structure function relation in multiblock copolymers with two crystalline phases exhibiting a temperature-memory effect by implementation of specific thermomechanical histories, which might be a general principle for tailoring other functions like mechanical strength or deformability in polymers. (C) 2016 Elsevier Ltd. All rights reserved. KW - Temperature-memory effect KW - Phase morphology KW - Thermomechanical history Y1 - 2016 U6 - https://doi.org/10.1016/j.polymer.2016.08.105 SN - 0032-3861 SN - 1873-2291 VL - 102 SP - 54 EP - 62 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Yan, Wan A1 - Fang, Liang A1 - Nöchel, Ulrich A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Influence of programming strain rates on the shape-memory performance of semicrystalline multiblock copolymers JF - Journal of polymer science : B, Polymer physics N2 - Multiblock copolymers named PCL-PIBMD consisting of crystallizable poly(epsilon-caprolactone) segments and crystallizable poly[oligo(3S-iso-butylmorpholine-2,5-dione)] segments coupled by trimethyl hexamethylene diisocyanate provide a versatile molecular architecture for achieving shape-memory effects (SMEs) in polymers. The mechanical properties as well as the SME performance of PCL-PIBMD can be tailored by the variation of physical parameters during programming such as deformation strain or applied temperature protocols. In this study, we explored the influence of applying different strain rates during programming on the resulting nanostructure of PCL-PIBMD. Programming was conducted at 50 degrees C by elongation to epsilon(m)=50% with strain rates of 1 or 10 or 50 mmmin(-1). The nanostructural changes were visualized by atomic force microscopy (AFM) measurements and investigated by in situ wide and small angle X-ray scattering experiments. With increasing the strain rate, a higher degree of orientation was observed in the amorphous domains. Simultaneously the strain-induced formation of new PIBMD crystals as well as the fragmentation of existing large PIBMD crystals occurred. The observed differences in shape fixity ratio and recovery stress of samples deformed with various strain rates can be attributed to their different nanostructures. The achieved findings can be relevant parameters for programming the shape-memory polymers with designed recovery forces. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1935-1943 KW - atomic force microscopy (AFM) KW - crystal structures KW - crystallization KW - multiblock copolymer KW - stimuli-sensitive polymers KW - SAXS KW - shape-memory effect KW - WAXS KW - X-ray scattering Y1 - 2016 U6 - https://doi.org/10.1002/polb.24097 SN - 0887-6266 SN - 1099-0488 VL - 54 SP - 1935 EP - 1943 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Balk, Maria A1 - Behl, Marc A1 - Nöchel, Ulrich A1 - Lendlein, Andreas T1 - Enzymatically triggered Jack-in-the-box-like hydrogels JF - ACS applied materials & interfaces / American Chemical Society N2 - Enzymes can support the synthesis or degradation of biomacromolecules in natural processes. Here, we demonstrate that enzymes can induce a macroscopic-directed movement of microstructured hydrogels following a mechanism that we call a "Jack-in-the-box" effect. The material's design is based on the formation of internal stresses induced by a deformation load on an architectured microscale, which are kinetically frozen by the generation of polyester locking domains, similar to a Jack-in-thebox toy (i.e., a compressed spring stabilized by a closed box lid). To induce the controlled macroscopic movement, the locking domains are equipped with enzyme-specific cleavable bonds (i.e., a box with a lock and key system). As a result of enzymatic reaction, a transformed shape is achieved by the release of internal stresses. There is an increase in entropy in combination with a swelling-supported stretching of polymer chains within the microarchitectured hydrogel (i.e., the encased clown pops-up with a pre-stressed movement when the box is unlocked). This utilization of an enzyme as a physiological stimulus may offer new approaches to create interactive and enzyme-specific materials for different applications such as an optical indicator of the enzyme's presence or actuators and sensors in biotechnology and in fermentation processes. KW - enzyme KW - hydrogels KW - stimuli-sensitive materials KW - shape change KW - poly(e-caprolactone) KW - switch KW - microporous Y1 - 2021 U6 - https://doi.org/10.1021/acsami.1c00466 SN - 1944-8244 SN - 1944-8252 VL - 13 IS - 7 SP - 8095 EP - 8101 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Wang, Weiwei A1 - Naolou, Toufik A1 - Ma, Nan A1 - Deng, Zijun A1 - Xu, Xun A1 - Mansfeld, Ulrich A1 - Wischke, Christian A1 - Gossen, Manfred A1 - Neffe, Axel T. A1 - Lendlein, Andreas T1 - Polydepsipeptide Block-Stabilized Polyplexes for Efficient Transfection of Primary Human Cells JF - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences N2 - The rational design of a polyplex gene carrier aims to balance maximal effectiveness of nucleic acid transfection into cells with minimal adverse effects. Depsipeptide blocks with an M (n) similar to 5 kDa exhibiting strong physical interactions were conjugated with PEI moieties (2.5 or 10 kDa) to di- and triblock copolymers. Upon nanoparticle formation and complexation with DNA, the resulting polyplexes (sizes typically 60-150 nm) showed remarkable stability compared to PEI-only or lipoplex and facilitated efficient gene delivery. Intracellular trafficking was visualized by observing fluorescence-labeled pDNA and highlighted the effective cytoplasmic uptake of polyplexes and release of DNA to the perinuclear space. Specifically, a triblock copolymer with a middle depsipeptide block and two 10 kDa PEI swallowtail structures mediated the highest levels of transgenic VEGF secretion in mesenchymal stem cells with low cytotoxicity. These nanocarriers form the basis for a delivery platform technology, especially for gene transfer to primary human cells. Y1 - 2017 U6 - https://doi.org/10.1021/acs.biomac.7b01034 SN - 1525-7797 SN - 1526-4602 VL - 18 SP - 3819 EP - 3833 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Zaupa, Alessandro A1 - Neffe, Axel T. A1 - Pierce, Benjamin F. A1 - Nöchel, Ulrich A1 - Lendlein, Andreas T1 - Influence of tyrosine-derived moieties and drying conditions on the formation of helices in gelatin JF - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences N2 - The single and triple helical organization of protein chains strongly influences the mechanical properties of gelatin-based materials. A chemical method for obtaining different degrees of helical organization in gelatin is covalent functionalization, while a physical method for achieving the same goal is the variation of the drying conditions of gelatin solutions. Here we explored how the introduction of desaminotyrosine (DAT) and desaminotyrosyl tyrosine (DATT) linked to lysine residues of gelatin influenced the kinetics and thermodynamic equilibrium of the helicalization process of single and triple helices following different drying conditions. Drying at a temperature above. the helix-to-coil transition temperature of gelatin (T > T-c, called nu(short)) generally resulted in gelatins with relatively lower triple helical content (X-c,X-t = 1-2%) than lower temperature drying (T < T-c, called nu(long)) (X-c,X-t = 8-10%), where the DAT(T) functional groups generally disrupted helix formation. While different helical contents affected the thermal transition temperatures only slightly, the mechanical properties were strongly affected for swollen hydrogels (E = 4-13 kPa for samples treated by nu(long) and E = 120-700 kPa for samples treated by nu(short)). This study shows that side group functionalization and different drying conditions are viable options to control the helicalization and macroscopic properties of gelatin-based materials. Y1 - 2011 U6 - https://doi.org/10.1021/bm101029k SN - 1525-7797 VL - 12 IS - 1 SP - 75 EP - 81 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Brunacci, Nadia A1 - Neffe, Axel T. A1 - Wischke, Christian A1 - Naolou, Toufik A1 - Nöchel, Ulrich A1 - Lendlein, Andreas T1 - Oligodepsipeptide (nano)carriers BT - computational design and analysis of enhanced drug loading JF - Journal of controlled release N2 - High drug loads of nanoparticles are essential to efficiently provide a desired dosage in the required timeframe, however, these conditions may not be reached with so far established degradable matrices. Our conceptual approach for increasing the drug load is based on strengthening the affinity between drug and matrix in combination with stabilizing drug-matrix-hybrids through strong intermolecular matrix interactions. Here, a method for designing such complex drug-matrix hybrids is introduced employing computational methods (molecular dynamics and docking) as well as experimental studies (affinity, drug loading and distribution, drug release from films and nanoparticles). As model system, dexamethasone (DXM), relevant for the treatment of inflammatory diseases, in combination with poly[(rac-lactide)-co-glycolide] (PLGA) as standard degradable matrix or oligo[(3-(S)-sec-butyl) morpholine-2,5-dione] diol (OBMD) as matrix with hypothesized stronger interaction with DXM were investigated. Docking studies predicted higher affinity of DXM to OBMD than PLGA and displayed amide bond participation in hydrogen bonding with OBMD. Experimental investigations on films and nanoparticles, i.e. matrices of different shapes and sizes, confirmed this phenomenon as shown e.g. by a similar to 10 times higher solid state solubility of DXM in OBMD than in PLGA. DXM-loaded particles of similar to 150 nm prepared by nanoprecipitation in aqueous environment had a drug loading (DL) up to 16 times higher when employing OBMD as matrix compared to PLGA carriers due to enhanced drug retention in the OBMD phase. Importantly, drug relase periods were not altered as the release from films and particles was mainly ruled by the diffusion length as well as matrix degradation rather than the matrix type, which can be assigned to water diffusing into the matrix and breaking up of drug-matrix hydrogen bonds. Overall, the presented design and fabrication scheme showed predictive power and might universally enable the screening of drug/matrix interactions particularly to expand the oligodepsipeptide platform technology, e.g. by varying the depsipeptide side chains, for drug carrier and release systems. KW - Oligodepsipeptide KW - Drug loading KW - Nanoparticles KW - Docking study KW - Molecular interaction design Y1 - 2019 U6 - https://doi.org/10.1016/j.jconrel.2019.03.004 SN - 0168-3659 SN - 1873-4995 VL - 301 SP - 146 EP - 156 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Piluso, Susanna A1 - Vukicevie, Radovan A1 - Nöchel, Ulrich A1 - Braune, Steffen A1 - Lendlein, Andreas A1 - Neffe, Axel T. T1 - Sequential alkyne-azide cycloadditions for functionalized gelatin hydrogel formation JF - European polymer journal N2 - While click chemistry reactions for biopolymer network formation are attractive as the defined reactions may allow good control of the network formation and enable subsequent functionalization, tailoring of gelatin network properties over a wide range of mechanical properties has yet to be shown. Here, it is demonstrated that copper-catalyzed alkyne-azide cycloaddition of alkyne functionalized gelatin with diazides gave hydrogel networks with properties tailorable by the ratio of diazide to gelatin and diazide rigidity. 4,4′-diazido-2,2′-stilbenedisulfonic acid, which has been used as rigid crosslinker, yielded hydrogels with Young’s moduli E of 50–390 kPa and swelling degrees Q of 150–250 vol.%, while the more flexible 1,8-diazidooctane resulted in hydrogels with E = 125–280 kPa and Q = 225–470 vol.%. Storage moduli could be varied by two orders of magnitude (G′ = 100–20,000 Pa). An indirect cytotoxicity test did not show cytotoxic properties. Even when employing 1:1 ratios of alkyne and azide moieties, the hydrogels were shown to contain both, unreacted alkyne groups on the gelatin backbone as well as dangling chains carrying azide groups as shown by reaction with functionalized fluorescein. The free groups, which can be tailored by the employed ratio of the reactants, are accessible for covalent attachment of drugs, as was demonstrated by functionalization with dexamethasone. The sequential network formation and functionalization with click chemistry allows access to multifunctional materials relevant for medical applications. KW - Click chemistry KW - Hydrogel KW - Polymer functionalization KW - Biopolymer KW - Rheology KW - Multifunctionality Y1 - 2018 U6 - https://doi.org/10.1016/j.eurpolymj.2018.01.017 SN - 0014-3057 SN - 1873-1945 VL - 100 SP - 77 EP - 85 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Hillwig, Todd C. A1 - Reindl, Nicole A1 - Rotter, Hannah M. A1 - Rengstorf, Adam W. A1 - Heber, Ulrich A1 - Irrgang, Andreas T1 - Two evolved close binary stars: GALEX J015054.4+310745 and the central star of the planetary nebula Hen 2-84 JF - Monthly notices of the Royal Astronomical Society N2 - As part of a survey to find close binary systems among central stars of planetary nebula, we present two newly discovered binary systems. GALEX J015054.4+310745 is identified as the central star of the possible planetary nebula Fr 2-22. We find it to be a single-lined spectroscopic binary with an orbital period of 0.2554435(10) d. We support the previous identification of GALEX J015054.4+310745 as an sdB star and provide physical parameters for the star from spectral modelling. We identify its undetected companion as a likely He white dwarf. Based on this information, we find it unlikely that Fr 2-22 is a true planetary nebula. In addition, the central star of the true planetary nebula Hen 2-84 is found to be a photometric variable, likely due to the irradiation of a cool companion. The system has an orbital period of 0.485645(30) d. We discuss limits on binary parameters based on the available light-curve data. Hen 2-84 is a strongly shaped bipolar planetary nebula, which we now add to the growing list of axially or point-symmetric planetary nebulae with a close binary central star. KW - binaries: close KW - stars: individual: GALEX J015054.4+310745 KW - subdwarfs KW - planetary nebulae: individual: Hen 2-84 Y1 - 2022 U6 - https://doi.org/10.1093/mnras/stac226 SN - 0035-8711 SN - 1365-2966 VL - 511 IS - 2 SP - 2033 EP - 2039 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Schiefele, Ulrich A1 - Raabe, Andreas T1 - SKILLS-DEMANDS COMPATIBILITY AS A DETERMINANT OF FLOW EXPERIENCE IN AN INDUCTIVE REASONING TASK JF - PSYCHOLOGICAL REPORTS N2 - The skills-demands fit hypothesis of flow theory was examined. Based on the earlier finding that high demands in a game situation do not reduce the experience of flow, a cognitive task paradigm was used. The effect of skills-demands compatibility on the experience of flow but not of other, similar psychological states (i.e., concentration, negative and positive activation) was also investigated. Participants were 89 undergraduate students who worked on a number of inductive reasoning tasks in four successive trials with or without skills-demands compatibility. The results clearly supported the skills-demands fit hypothesis; concentration and activation were affected only by the tasks’ difficulty. Inductive reasoning tasks are a useful tool for the experimental analysis of flow, and skills-demands compatibility is a significant and powerful condition of flow, but not of other, similar psychological states. Y1 - 2011 U6 - https://doi.org/10.2466/04.22.PR0.109.5.428-444 SN - 0033-2941 VL - 109 IS - 2 SP - 428 EP - 444 PB - AMMONS SCIENTIFIC, LTD CY - MISSOULA ER - TY - JOUR A1 - Federico, Stefania A1 - Nöchel, Ulrich A1 - Löwenberg, Candy A1 - Lendlein, Andreas A1 - Neffe, Axel T. T1 - Supramolecular hydrogel networks formed by molecular recognition of collagen and a peptide grafted to hyaluronic acid JF - Acta biomaterialia N2 - The extracellular matrix (ECM) is a nano-structured, highly complex hydrogel, in which the macromolecules are organized primarily by non-covalent interactions. Here, in a biomimetic approach, the decorin-derived collagen-binding peptide LSELRLHNN was grafted to hyaluronic acid (HA) in order to enable the formation of a supramolecular hydrogel network together with collagen. The storage modulus of a mixture of collagen and HA was increased by more than one order of magnitude (G′ = 157 Pa) in the presence of the HA-grafted peptide compared to a mixture of collagen and HA (G′ = 6 Pa). The collagen fibril diameter was decreased, as quantified using electron microscopy, in the presence of the HA-grafted peptide. Here, the peptide mimicked the function of decorin by spatially organizing collagen. The advantage of this approach is that the non-covalent crosslinks between collagen molecules and the HA chains created by the peptide form a reversible and dynamic hydrogel, which could be employed for a diverse range of applications in regenerative medicine. Statement of Significance Biopolymers of the extracellular matrix (ECM) like collagen or hyaluronan are attractive starting materials for biomaterials. While in biomaterial science covalent crosslinking is often employed, in the native ECM, stabilization and macromolecular organization is primarily based on non-covalent interactions, which allows dynamic changes of the materials. Here, we show that collagen-binding peptides, derived from the small proteoglycan decorin, grafted to hyaluronic acid enable supramolecular stabilization of collagen hydrogels. These hydrogels have storage moduli more than one order of magnitude higher than mixtures of collagen and hyaluronic acid. Furthermore, the peptide supported the structural organization of collagen. Such hydrogels could be employed for a diverse range of applications in regenerative medicine. Furthermore, the rational design helps in the understanding ECM structuring. KW - Biopolymers KW - Collagen-binding peptide KW - Hyaluronic acid KW - Hydrogels KW - Mechanical properties Y1 - 2016 U6 - https://doi.org/10.1016/j.actbio.2016.04.018 SN - 1742-7061 SN - 1878-7568 VL - 38 SP - 1 EP - 10 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Farhan, Muhammad A1 - Rudolph, Tobias A1 - Nöchel, Ulrich A1 - Yan, Wan A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Noncontinuously Responding Polymeric Actuators JF - ACS applied materials & interfaces N2 - Reversible movements of current polymeric actuators stem from the continuous response to signals from a controlling unit, and subsequently cannot be interrupted without stopping or eliminating the input trigger. Here, we present actuators based on cross-linked blends of two crystallizable polymers capable of pausing their movements in a defined manner upon continuous cyclic heating and cooling. This noncontinuous actuation can be adjusted by varying the applied heating and cooling rates. The feasibility of these devices for technological applications was shown in a 140 cycle experiment of free-standing noncontinuous shape shifts, as well as by various demonstrators. KW - soft robotics KW - polymer actuators KW - thermo-sensitivity KW - shape shifting materials KW - crystallization behavior Y1 - 2017 U6 - https://doi.org/10.1021/acsami.7b11316 SN - 1944-8244 VL - 9 SP - 33559 EP - 33564 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Farhan, Muhammad A1 - Rudolph, Tobias A1 - Nöchel, Ulrich A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Extractable Free Polymer Chains Enhance Actuation Performance of Crystallizable Poly(epsilon-caprolactone) Networks and Enable Self-Healing JF - Polymers N2 - Crosslinking of thermoplastics is a versatile method to create crystallizable polymer networks, which are of high interest for shape-memory actuators. Here, crosslinked poly(epsilon-caprolactone) thermosets (cPCLs) were prepared from linear starting material, whereby the amount of extractable polymer was varied. Fractions of 5-60 wt % of non-crosslinked polymer chains, which freely interpenetrate the crosslinked network, were achieved leading to differences in the resulting phase of the bulk material. This can be described as "sponge-like" with open or closed compartments depending on the amount of interpenetrating polymer. The crosslinking density and the average network chain length remained in a similar range for all network structures, while the theoretical accessible volume for reptation of the free polymer content is affected. This feature could influence or introduce new functions into the material created by thermomechanical treatment. The effect of interpenetrating PCL in cPCLs on the reversible actuation was analyzed by cyclic, uniaxial tensile tests. Here, high reversible strains of up to Delta epsilon = 24% showed the enhanced actuation performance of networks with a non-crosslinked PCL content of 30 wt % resulting from the crystal formation in the phase of the non-crosslinked PCL and co-crystallization with network structures. Additional functionalities are reprogrammability and self-healing capabilities for networks with high contents of extractable polymer enabling reusability and providing durable actuator materials. KW - shape-memory polymer actuators KW - soft actuators KW - self-healing KW - poly(epsilon-caprolactone) KW - thermoplastics Y1 - 2018 U6 - https://doi.org/10.3390/polym10030255 SN - 2073-4360 VL - 10 IS - 3 PB - MDPI CY - Basel ER - TY - JOUR A1 - Borchert, Florian A1 - Mock, Andreas A1 - Tomczak, Aurelie A1 - Hügel, Jonas A1 - Alkarkoukly, Samer A1 - Knurr, Alexander A1 - Volckmar, Anna-Lena A1 - Stenzinger, Albrecht A1 - Schirmacher, Peter A1 - Debus, Jürgen A1 - Jäger, Dirk A1 - Longerich, Thomas A1 - Fröhling, Stefan A1 - Eils, Roland A1 - Bougatf, Nina A1 - Sax, Ulrich A1 - Schapranow, Matthieu-Patrick T1 - Correction to: Knowledge bases and software support for variant interpretation in precision oncology JF - Briefings in bioinformatics Y1 - 2021 U6 - https://doi.org/10.1093/bib/bbab246 SN - 1467-5463 SN - 1477-4054 VL - 22 IS - 6 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Dorsch, Matti A1 - Jeffery, C. Simon A1 - Irrgang, Andreas A1 - Woolf, Vincent A1 - Heber, Ulrich T1 - EC 22536-5304 BT - a lead-rich and metal-poor long-period binary JF - Astronomy and astrophysics : an international weekly journal N2 - Helium-burning hot subdwarf stars of spectral types O and B (sdO/B) are thought to be produced through various types of binary interactions. The helium-rich hot subdwarf star EC 22536-5304 was recently found to be extremely enriched in lead. Here, we show that EC 22536-5304 is a binary star with a metal-poor subdwarf F-type (sdF) companion. We performed a detailed analysis of high-resolution SALT/HRS and VLT/UVES spectra, deriving metal abundances for the hot subdwarf, as well as atmospheric parameters for both components. Because we consider the contribution of the sdF star, the derived lead abundance for the sdOB, + 6.3 +/- 0.3 dex relative to solar, is even higher than previously thought. We derive T-eff = 6210 +/- 70 K, log g = 4.64 +/- 0.10, [FE/H] = - 1.95 +/- 0.04, and [alpha/Fe] = + 0.40 +/- 0.04 for the sdF component. Radial velocity variations, although poorly sampled at present, indicate that the binary system has a long orbital period of about 457 days. This suggests that the system was likely formed through stable Roche lobe overflow (RLOF). A kinematic analysis shows that EC 22536-5304 is on an eccentric orbit around the Galactic centre. This, as well as the low metallicity and strong alpha enhancement of the sdF-type companion, indicate that EC 22536-5304 is part of the Galactic halo or metal-weak thick disc. As the first long-period hot subdwarf binary at [FE/H] less than or similar to- 1, EC 22536-5304 may help to constrain the RLOF mechanism for mass transfer from low-mass, low-metallicity red giant branch (RGB) stars to main-sequence companions. KW - stars: abundances KW - stars: chemically peculiar KW - subdwarfs KW - stars: individual: EC 22536-5304 KW - binaries: spectroscopic Y1 - 2021 U6 - https://doi.org/10.1051/0004-6361/202141381 SN - 1432-0746 VL - 653 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Willmann, Caroline A1 - Heni, Martin A1 - Linder, Katarzyna A1 - Wagner, Robert A1 - Stefan, Norbert A1 - Machann, Jürgen A1 - Schulze, Matthias Bernd A1 - Joost, Hans-Georg A1 - Haring, Hans-Ulrich A1 - Fritsche, Andreas T1 - Potential effects of reduced red meat compared with increased fiber intake on glucose metabolism and liver fat content BT - a randomized and controlled dietary intervention study JF - The American journal of clinical nutrition : a publication of the American Society for Nutrition, Inc. N2 - Background: Epidemiological studies suggest that an increased red meat intake is associated with a higher risk of type 2 diabetes, whereas an increased fiber intake is associated with a lower risk. Objectives: We conducted an intervention study to investigate the effects of these nutritional factors on glucose and lipid metabolism, body-fat distribution, and liver fat content in subjects at increased risk of type 2 diabetes. Methods: This prospective, randomized, and controlled dietary intervention study was performed over 6 mo. All groups decreased their daily caloric intake by 400 kcal. The "control" group (N = 40) only had this requirement. The "no red meat" group (N = 48) in addition aimed to avoid the intake of red meat, and the "fiber" group (N = 44) increased intake of fibers to 40 g/d. Anthropometric parameters and frequently sampled oral glucose tolerance tests were performed before and after intervention. Body-fat mass and distribution, liver fat, and liver iron content were assessed by MRI and single voxel proton magnetic resonance spectroscopy. Results: Participants in all groups lost weight (mean 3.3 +/- 0.5 kg, P < 0.0001). Glucose tolerance and insulin sensitivity improved (P < 0.001), and body and visceral fat mass decreased in all groups (P < 0.001). These changes did not differ between groups. Liver fat content decreased significantly (P < 0.001) with no differences between the groups. The decrease in liver fat correlated with the decrease in ferritin during intervention (r(2) = 0.08, P = 0.0021). This association was confirmed in an independent lifestyle intervention study (Tuebingen Lifestyle Intervention Program, N = 229, P = 0.0084). Conclusions: Our data indicate that caloric restriction leads to a marked improvement in glucose metabolism and body-fat composition, including liver-fat content. The marked reduction in liver fat might be mediated via changes in ferritin levels. In the context of caloric restriction, there seems to be no additional beneficial impact of reduced red meat intake and increased fiber intake on the improvement in cardiometabolic risk parameters. This trial was registered at clinicaltrials.gov as NCT03231839. KW - type 2 diabetes KW - prevention KW - randomized controlled intervention study KW - nutritional factors KW - fiber KW - red meat Y1 - 2019 U6 - https://doi.org/10.1093/ajcn/nqy307 SN - 0002-9165 SN - 1938-3207 VL - 109 IS - 2 SP - 288 EP - 296 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - de Vera, Jean-Pierre Paul A1 - Böttger, Ute A1 - de la Torre Nötzel, Rosa A1 - Sanchez, Francisco J. A1 - Grunow, Dana A1 - Schmitz, Nicole A1 - Lange, Caroline A1 - Hübers, Heinz-Wilhelm A1 - Billi, Daniela A1 - Baque, Mickael A1 - Rettberg, Petra A1 - Rabbow, Elke A1 - Reitz, Günther A1 - Berger, Thomas A1 - Möller, Ralf A1 - Bohmeier, Maria A1 - Horneck, Gerda A1 - Westall, Frances A1 - Jänchen, Jochen A1 - Fritz, Jörg A1 - Meyer, Cornelia A1 - Onofri, Silvano A1 - Selbmann, Laura A1 - Zucconi, Laura A1 - Kozyrovska, Natalia A1 - Leya, Thomas A1 - Foing, Bernard A1 - Demets, Rene A1 - Cockell, Charles S. A1 - Bryce, Casey A1 - Wagner, Dirk A1 - Serrano, Paloma A1 - Edwards, Howell G. M. A1 - Joshi, Jasmin Radha A1 - Huwe, Björn A1 - Ehrenfreund, Pascale A1 - Elsaesser, Andreas A1 - Ott, Sieglinde A1 - Meessen, Joachim A1 - Feyh, Nina A1 - Szewzyk, Ulrich A1 - Jaumann, Ralf A1 - Spohn, Tilman T1 - Supporting Mars exploration BIOMEX in Low Earth Orbit and further astrobiological studies on the Moon using Raman and PanCam technology JF - Planetary and space science N2 - The Low Earth Orbit (LEO) experiment Biology and Mars Experiment (BIOMEX) is an interdisciplinary and international space research project selected by ESA. The experiment will be accommodated on the space exposure facility EXPOSE-R2 on the International Space Station (ISS) and is foreseen to be launched in 2013. The prime objective of BIOMEX is to measure to what extent biomolecules, such as pigments and cellular components, are resistant to and able to maintain their stability under space and Mars-like conditions. The results of BIOMEX will be relevant for space proven biosignature definition and for building a biosignature data base (e.g. the proposed creation of an international Raman library). The library will be highly relevant for future space missions such as the search for life on Mars. The secondary scientific objective is to analyze to what extent terrestrial extremophiles are able to survive in space and to determine which interactions between biological samples and selected minerals (including terrestrial, Moon- and Mars analogs) can be observed under space and Mars-like conditions. In this context, the Moon will be an additional platform for performing similar experiments with negligible magnetic shielding and higher solar and galactic irradiation compared to LEO. Using the Moon as an additional astrobiological exposure platform to complement ongoing astrobiological LEO investigations could thus enhance the chances of detecting organic traces of life on Mars. We present a lunar lander mission with two related objectives: a lunar lander equipped with Raman and PanCam instruments which can analyze the lunar surface and survey an astrobiological exposure platform. This dual use of testing mission technology together with geo- and astrobiological analyses will significantly increase the science return, and support the human preparation objectives. It will provide knowledge about the Moon's surface itself and, in addition, monitor the stability of life-markers, such as cells, cell components and pigments, in an extraterrestrial environment with much closer radiation properties to the surface of Mars. The combination of a Raman data base of these data together with data from LEO and space simulation experiments, will lead to further progress on the analysis and interpretation of data that we will obtain from future Moon and Mars exploration missions. KW - Moon KW - Mars KW - Low Earth Orbit KW - Astrobiology KW - Instrumentation KW - Spectroscopy KW - Biosignature Y1 - 2012 U6 - https://doi.org/10.1016/j.pss.2012.06.010 SN - 0032-0633 VL - 74 IS - 1 SP - 103 EP - 110 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Nikolis, Vasileios C. A1 - Mischok, Andreas A1 - Siegmund, Bernhard A1 - Kublitski, Jonas A1 - Jia, Xiangkun A1 - Benduhn, Johannes A1 - Hörmann, Ulrich A1 - Neher, Dieter A1 - Gather, Malte C. A1 - Spoltore, Donato A1 - Vandewal, Koen T1 - Strong light-matter coupling for reduced photon energy losses in organic photovoltaics JF - Nature Communications N2 - Strong light-matter coupling can re-arrange the exciton energies in organic semiconductors. Here, we exploit strong coupling by embedding a fullerene-free organic solar cell (OSC) photo-active layer into an optical microcavity, leading to the formation of polariton peaks and a red-shift of the optical gap. At the same time, the open-circuit voltage of the device remains unaffected. This leads to reduced photon energy losses for the low-energy polaritons and a steepening of the absorption edge. While strong coupling reduces the optical gap, the energy of the charge-transfer state is not affected for large driving force donor-acceptor systems. Interestingly, this implies that strong coupling can be exploited in OSCs to reduce the driving force for electron transfer, without chemical or microstructural modifications of the photoactive layer. Our work demonstrates that the processes determining voltage losses in OSCs can now be tuned, and reduced to unprecedented values, simply by manipulating the device architecture. Y1 - 2019 U6 - https://doi.org/10.1038/s41467-019-11717-5 SN - 2041-1723 VL - 10 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Jeltsch, Florian A1 - Blaum, Niels A1 - Brose, Ulrich A1 - Chipperfield, Joseph D. A1 - Clough, Yann A1 - Farwig, Nina A1 - Geissler, Katja A1 - Graham, Catherine H. A1 - Grimm, Volker A1 - Hickler, Thomas A1 - Huth, Andreas A1 - May, Felix A1 - Meyer, Katrin M. A1 - Pagel, Jörn A1 - Reineking, Björn A1 - Rillig, Matthias C. A1 - Shea, Katriona A1 - Schurr, Frank Martin A1 - Schroeder, Boris A1 - Tielbörger, Katja A1 - Weiss, Lina A1 - Wiegand, Kerstin A1 - Wiegand, Thorsten A1 - Wirth, Christian A1 - Zurell, Damaris T1 - How can we bring together empiricists and modellers in functional biodiversity research? JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - Improving our understanding of biodiversity and ecosystem functioning and our capacity to inform ecosystem management requires an integrated framework for functional biodiversity research (FBR). However, adequate integration among empirical approaches (monitoring and experimental) and modelling has rarely been achieved in FBR. We offer an appraisal of the issues involved and chart a course towards enhanced integration. A major element of this path is the joint orientation towards the continuous refinement of a theoretical framework for FBR that links theory testing and generalization with applied research oriented towards the conservation of biodiversity and ecosystem functioning. We further emphasize existing decision-making frameworks as suitable instruments to practically merge these different aims of FBR and bring them into application. This integrated framework requires joint research planning, and should improve communication and stimulate collaboration between modellers and empiricists, thereby overcoming existing reservations and prejudices. The implementation of this integrative research agenda for FBR requires an adaptation in most national and international funding schemes in order to accommodate such joint teams and their more complex structures and data needs. KW - Biodiversity theory KW - Biodiversity experiments KW - Conservation management KW - Decision-making KW - Ecosystem functions and services KW - Forecasting KW - Functional traits KW - Global change KW - Monitoring programmes KW - Interdisciplinarity Y1 - 2013 U6 - https://doi.org/10.1016/j.baae.2013.01.001 SN - 1439-1791 VL - 14 IS - 2 SP - 93 EP - 101 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Reverey, Florian A1 - Ganzert, Lars A1 - Lischeid, Gunnar A1 - Ulrich, Andreas A1 - Premke, Katrin A1 - Grossart, Hans-Peter T1 - Dry-wet cycles of kettle hole sediments leave a microbial and biogeochemical legacy JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Understanding interrelations between an environment's hydrological past and its current biogeochemistry is necessary for the assessment of biogeochemical and microbial responses to changing hydrological conditions. The question how previous dry-wet events determine the contemporary microbial and biogeochemical state is addressed in this study. Therefore, sediments exposed to the atmosphere of areas with a different hydrological past within one kettle hole, i.e. (1) the predominantly inundated pond center, (2) the pond margin frequently desiccated for longer periods and (3) an intermediate zone, were incubated with the same rewetting treatment. Physicochemical and textural characteristics were related to structural microbial parameters regarding carbon and nitrogen turnover, i.e. abundance of bacteria and fungi, denitrifiers (targeted by the nirK und nirS functional genes) and nitrate ammonifiers (targeted by the nrfA functional gene). Our study reveals that, in combination with varying sediment texture, the hydrological history creates distinct microbial habitats with defined boundary conditions within the kettle hole, mainly driven by redox conditions, pH and organic matter (OM) composition. OM mineralization, as indicated by CO2-outgassing, was most efficient in exposed sediments with a less stable hydrological past. The potential for nitrogen retention via nitrate ammonification was highest in the hydrologically rather stable pond center, counteracting nitrogen loss due to denitrification. Therefore, the degree of hydrological stability is an important factor leaving a microbial and biogeochemical legacy, which determines carbon and nitrogen losses from small lentic freshwater systems in the long term run. KW - Desiccation KW - DNRA KW - Denitrifiers KW - Organic matter mineralization KW - Carbon KW - Nitrogen Y1 - 2018 U6 - https://doi.org/10.1016/j.scitotenv.2018.01.220 SN - 0048-9697 SN - 1879-1026 VL - 627 SP - 985 EP - 996 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Fabian, Jenny A1 - Zlatanovic, Sanja A1 - Mutz, Michael A1 - Grossart, Hans-Peter A1 - van Geldern, Robert A1 - Ulrich, Andreas A1 - Gleixner, Gerd A1 - Premke, Katrin T1 - Environmental control on microbial turnover of leaf carbon in streams BT - Ecological function of phototrophic-heterotrophic interactions JF - Frontiers in microbiology N2 - In aquatic ecosystems, light availability can significantly influence microbial turnover of terrestrial organic matter through associated metabolic interactions between phototrophic and heterotrophic communities. However, particularly in streams, microbial functions vary significantly with the structure of the streambed, that is the distribution and spatial arrangement of sediment grains in the streambed. It is therefore essential to elucidate how environmental factors synergistically define the microbial turnover of terrestrial organic matter in order to better understand the ecological role of photoheterotrophic interactions in stream ecosystem processes. In outdoor experimental streams, we examined how the structure of streambeds modifies the influence of light availability on microbial turnover of leaf carbon (C). Furthermore, we investigated whether the studied relationships of microbial leaf C turnover to environmental conditions are affected by flow intermittency commonly occurring in streams. We applied leaves enriched with a C-13-stable isotope tracer and combined quantitative and isotope analyses. We thereby elucidated whether treatment induced changes in C turnover were associated with altered use of leaf C within the microbial food web. Moreover, isotope analyses were combined with measurements of microbial community composition to determine whether changes in community function were associated with a change in community composition. In this study, we present evidence, that environmental factors interactively determine how phototrophs and heterotrophs contribute to leaf C turnover. Light availability promoted the utilization of leaf C within the microbial food web, which was likely associated with a promoted availability of highly bioavailable metabolites of phototrophic origin. However, our results additionally confirm that the structure of the streambed modifies light-related changes in microbial C turnover. From our observations, we conclude that the streambed structure influences the strength of photo-heterotrophic interactions by defining the spatial availability of algal metabolites in the streambed and the composition of microbial communities. Collectively, our multifactorial approach provides valuable insights into environmental controls on the functioning of stream ecosystems. KW - algae KW - bacteria KW - microbial interactions KW - C-13 stable isotopes KW - PLFA KW - terrestrial carbon KW - streambed structure KW - light Y1 - 2018 U6 - https://doi.org/10.3389/fmicb.2018.01044 SN - 1664-302X VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Garbusow, Maria A1 - Schad, Daniel A1 - Sommer, Christian A1 - Juenger, Elisabeth A1 - Sebold, Miriam A1 - Friedel, Eva A1 - Wendt, Jean A1 - Kathmann, Norbert A1 - Schlagenhauf, Florian A1 - Zimmermann, Ulrich S. A1 - Heinz, Andreas A1 - Huys, Quentin J. M. A1 - Rapp, Michael A. T1 - Pavlovian-to-instrumental transfer in alcohol dependence: a pilot study JF - Neuropsychobiology : international journal of experimental and clinical research in biological psychiatry, pharmacopsychiatry, Biological Psychology/Pharmacopsychology and Pharmacoelectroencephalography N2 - Background: Pavlovian processes are thought to play an important role in the development, maintenance and relapse of alcohol dependence, possibly by influencing and usurping ongoing thought and behavior. The influence of pavlovian stimuli on ongoing behavior is paradigmatically measured by pavlovian-to-instrumental transfer (PIT) tasks. These involve multiple stages and are complex. Whether increased PIT is involved in human alcohol dependence is uncertain. We therefore aimed to establish and validate a modified PIT paradigm that would be robust, consistent and tolerated by healthy controls as well as by patients suffering from alcohol dependence, and to explore whether alcohol dependence is associated with enhanced PIT. Methods: Thirty-two recently detoxified alcohol-dependent patients and 32 age- and gender-matched healthy controls performed a PIT task with instrumental go/no-go approach behaviors. The task involved both pavlovian stimuli associated with monetary rewards and losses, and images of drinks. Results: Both patients and healthy controls showed a robust and temporally stable PIT effect. Strengths of PIT effects to drug-related and monetary conditioned stimuli were highly correlated. Patients more frequently showed a PIT effect, and the effect was stronger in response to aversively conditioned CSs (conditioned suppression), but there was no group difference in response to appetitive CSs. Conclusion: The implementation of PIT has favorably robust properties in chronic alcohol-dependent patients and in healthy controls. It shows internal consistency between monetary and drug-related cues. The findings support an association of alcohol dependence with an increased propensity towards PIT. KW - Pavlovian-to-instrumental transfer KW - Alcohol dependence KW - Human Y1 - 2014 U6 - https://doi.org/10.1159/000363507 SN - 0302-282X SN - 1423-0224 VL - 70 IS - 2 SP - 111 EP - 121 PB - Karger CY - Basel ER - TY - JOUR A1 - Sebold, Miriam A1 - Schad, Daniel A1 - Nebe, Stephan A1 - Garbusow, Maria A1 - Juenger, Elisabeth A1 - Kroemer, Nils B. A1 - Kathmann, Norbert A1 - Zimmermann, Ulrich S. A1 - Smolka, Michael N. A1 - Rapp, Michael A. A1 - Heinz, Andreas A1 - Huys, Quentin J. M. T1 - Pavlovian-to-Instrumental Transfer Effects Rely Less on Model-based Reinforcement Learning JF - Journal of cognitive neuroscience N2 - Behavioral choice can be characterized along two axes. One axis distinguishes reflexive, model-free systems that slowly accumulate values through experience and a model-based system that uses knowledge to reason prospectively. The second axis distinguishes Pavlovian valuation of stimuli from instrumental valuation of actions or stimulus–action pairs. This results in four values and many possible interactions between them, with important consequences for accounts of individual variation. We here explored whether individual variation along one axis was related to individual variation along the other. Specifically, we asked whether individuals' balance between model-based and model-free learning was related to their tendency to show Pavlovian interferences with instrumental decisions. In two independent samples with a total of 243 participants, Pavlovian–instrumental transfer effects were negatively correlated with the strength of model-based reasoning in a two-step task. This suggests a potential common underlying substrate predisposing individuals to both have strong Pavlovian interference and be less model-based and provides a framework within which to interpret the observation of both effects in addiction. Y1 - 2016 U6 - https://doi.org/10.1162/jocn_a_00945 SN - 0898-929X SN - 1530-8898 VL - 28 SP - 985 EP - 995 PB - MIT Press CY - Cambridge ER - TY - JOUR A1 - Schad, Daniel A1 - Juenger, Elisabeth A1 - Sebold, Miriam A1 - Garbusow, Maria A1 - Bernhardt, Nadine A1 - Javadi, Amir-Homayoun A1 - Zimmermann, Ulrich S. A1 - Smolka, Michael N. A1 - Heinz, Andreas A1 - Rapp, Michael A. A1 - Huys, Quentin J. M. T1 - Processing speed enhances model-based over model-free reinforcement learning in the presence of high working memory functioning JF - Frontiers in psychology N2 - Theories of decision-making and its neural substrates have long assumed the existence of two distinct and competing valuation systems, variously described as goal-directed vs. habitual, or, more recently and based on statistical arguments, as model-free vs. model-based reinforcement-learning. Though both have been shown to control choices, the cognitive abilities associated with these systems are under ongoing investigation. Here we examine the link to cognitive abilities, and find that individual differences in processing speed covary with a shift from model-free to model-based choice control in the presence of above-average working memory function. This suggests shared cognitive and neural processes; provides a bridge between literatures on intelligence and valuation; and may guide the development of process models of different valuation components. Furthermore, it provides a rationale for individual differences in the tendency to deploy valuation systems, which may be important for understanding the manifold neuropsychiatric diseases associated with malfunctions of valuation. KW - decision-making KW - reward KW - cognitive abilities KW - model-based and model-free learning KW - fluid intelligence KW - habitual and goal-directed system Y1 - 2014 U6 - https://doi.org/10.3389/fpsyg.2014.01450 SN - 1664-1078 VL - 5 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Friedel, Eva A1 - Sebold, Miriam A1 - Kuitunen-Paul, Sören A1 - Nebe, Stephan A1 - Veer, Ilya M. A1 - Zimmermann, Ulrich S. A1 - Schlagenhauf, Florian A1 - Smolka, Michael N. A1 - Rapp, Michael A. A1 - Walter, Henrik A1 - Heinz, Andreas T1 - How Accumulated Real Life Stress Experience and Cognitive Speed Interact on Decision-Making Processes JF - Frontiers in human neuroscienc N2 - Rationale: Advances in neurocomputational modeling suggest that valuation systems for goal-directed (deliberative) on one side, and habitual (automatic) decision-making on the other side may rely on distinct computational strategies for reinforcement learning, namely model-free vs. model-based learning. As a key theoretical difference, the model-based system strongly demands cognitive functions to plan actions prospectively based on an internal cognitive model of the environment, whereas valuation in the model-free system relies on rather simple learning rules from operant conditioning to retrospectively associate actions with their outcomes and is thus cognitively less demanding. Acute stress reactivity is known to impair model-based but not model-free choice behavior, with higher working memory capacity protecting the model-based system from acute stress. However, it is not clear which impact accumulated real life stress has on model-free and model-based decision systems and how this influence interacts with cognitive abilities. Methods: We used a sequential decision-making task distinguishing relative contributions of both learning strategies to choice behavior, the Social Readjustment Rating Scale questionnaire to assess accumulated real life stress, and the Digit Symbol Substitution Test to test cognitive speed in 95 healthy subjects. Results: Individuals reporting high stress exposure who had low cognitive speed showed reduced model-based but increased model-free behavioral control. In contrast, subjects exposed to accumulated real life stress with high cognitive speed displayed increased model-based performance but reduced model-free control. Conclusion: These findings suggest that accumulated real life stress exposure can enhance reliance on cognitive speed for model-based computations, which may ultimately protect the model-based system from the detrimental influences of accumulated real life stress. The combination of accumulated real life stress exposure and slower information processing capacities, however, might favor model-free strategies. Thus, the valence and preference of either system strongly depends on stressful experiences and individual cognitive capacities. KW - chronic stress KW - model-based learning KW - model-free learning KW - decision making KW - cognitive speed KW - real-life events Y1 - 2017 U6 - https://doi.org/10.3389/fnhum.2017.00302 SN - 1662-5161 VL - 11 SP - 1 EP - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Garbusow, Maria A1 - Nebe, Stephan A1 - Sommer, Christian A1 - Kuitunen-Paul, Sören A1 - Sebold, Miriam A1 - Schad, Daniel A1 - Friedel, Eva A1 - Veer, Ilya M. A1 - Wittchen, Hans-Ulrich A1 - Rapp, Michael A. A1 - Ripke, Stephan A1 - Walter, Henrik A1 - Huys, Quentin J. M. A1 - Schlagenhauf, Florian A1 - Smolka, Michael N. A1 - Heinz, Andreas T1 - Pavlovian-To-Instrumental Transfer and Alcohol Consumption in Young Male Social Drinkers BT - Behavioral, Neural and Polygenic Correlates JF - Journal of Clinical Medicine N2 - In animals and humans, behavior can be influenced by irrelevant stimuli, a phenomenon called Pavlovian-to-instrumental transfer (PIT). In subjects with substance use disorder, PIT is even enhanced with functional activation in the nucleus accumbens (NAcc) and amygdala. While we observed enhanced behavioral and neural PIT effects in alcohol-dependent subjects, we here aimed to determine whether behavioral PIT is enhanced in young men with high-risk compared to low-risk drinking and subsequently related functional activation in an a-priori region of interest encompassing the NAcc and amygdala and related to polygenic risk for alcohol consumption. A representative sample of 18-year old men (n = 1937) was contacted: 445 were screened, 209 assessed: resulting in 191 valid behavioral, 139 imaging and 157 genetic datasets. None of the subjects fulfilled criteria for alcohol dependence according to the Diagnostic and Statistical Manual of Mental Disorders-IV-TextRevision (DSM-IV-TR). We measured how instrumental responding for rewards was influenced by background Pavlovian conditioned stimuli predicting action-independent rewards and losses. Behavioral PIT was enhanced in high-compared to low-risk drinkers (b = 0.09, SE = 0.03, z = 2.7, p < 0.009). Across all subjects, we observed PIT-related neural blood oxygen level-dependent (BOLD) signal in the right amygdala (t = 3.25, p(SVC) = 0.04, x = 26, y = -6, z = -12), but not in NAcc. The strength of the behavioral PIT effect was positively correlated with polygenic risk for alcohol consumption (r(s) = 0.17, p = 0.032). We conclude that behavioral PIT and polygenic risk for alcohol consumption might be a biomarker for a subclinical phenotype of risky alcohol consumption, even if no drug-related stimulus is present. The association between behavioral PIT effects and the amygdala might point to habitual processes related to out PIT task. In non-dependent young social drinkers, the amygdala rather than the NAcc is activated during PIT; possible different involvement in association with disease trajectory should be investigated in future studies. KW - Pavlovian-to-instrumental transfer KW - amygdala KW - alcohol KW - polygenic risk KW - high risk drinkers Y1 - 2019 U6 - https://doi.org/10.3390/jcm8081188 SN - 2077-0383 VL - 8 IS - 8 PB - MDPI CY - Basel ER - TY - JOUR A1 - Sebold, Miriam A1 - Chen, Hao A1 - Önal, Aleyna A1 - Kuitunen-Paul, Sören A1 - Mojtahedzadeh, Negin A1 - Garbusow, Maria A1 - Nebe, Stephan A1 - Wittchen, Hans-Ulrich A1 - Huys, Quentin J. M. A1 - Schlagenhauf, Florian A1 - Rapp, Michael A. A1 - Smolka, Michael N. A1 - Heinz, Andreas T1 - Stronger prejudices are associated with decreased model-based control JF - Frontiers in psychology N2 - Background: Prejudices against minorities can be understood as habitually negative evaluations that are kept in spite of evidence to the contrary. Therefore, individuals with strong prejudices might be dominated by habitual or "automatic" reactions at the expense of more controlled reactions. Computational theories suggest individual differences in the balance between habitual/model-free and deliberative/model-based decision-making. Methods: 127 subjects performed the two Step task and completed the blatant and subtle prejudice scale. Results: By using analyses of choices and reaction times in combination with computational modeling, subjects with stronger blatant prejudices showed a shift away from model-based control. There was no association between these decision-making processes and subtle prejudices. Conclusion: These results support the idea that blatant prejudices toward minorities are related to a relative dominance of habitual decision-making. This finding has important implications for developing interventions that target to change prejudices across societies. KW - subtle and blatant prejudice KW - immigrant KW - social behavior; KW - decision-making KW - computational modeling KW - reinforcement learning Y1 - 2022 U6 - https://doi.org/10.3389/fpsyg.2021.767022 SN - 1664-1078 VL - 12 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Sebold, Miriam A1 - Nebe, Stephan A1 - Garbusow, Maria A1 - Guggenmos, Matthias A1 - Schad, Daniel A1 - Beck, Anne A1 - Kuitunen-Paul, Sören A1 - Sommer, Christian A1 - Frank, Robin A1 - Neu, Peter A1 - Zimmermann, Ulrich S. A1 - Rapp, Michael A. A1 - Smolka, Michael N. A1 - Huys, Quentin J. M. A1 - Schlagenhauf, Florian A1 - Heinz, Andreas T1 - When Habits Are Dangerous: Alcohol Expectancies and Habitual Decision Making Predict Relapse in Alcohol Dependence JF - Biological psychiatry : a journal of psychiatric neuroscience and therapeutics ; a publication of the Society of Biological Psychiatry N2 - BACKGROUND: Addiction is supposedly characterized by a shift from goal-directed to habitual decision making, thus facilitating automatic drug intake. The two-step task allows distinguishing between these mechanisms by computationally modeling goal-directed and habitual behavior as model-based and model-free control. In addicted patients, decision making may also strongly depend upon drug-associated expectations. Therefore, we investigated model-based versus model-free decision making and its neural correlates as well as alcohol expectancies in alcohol-dependent patients and healthy controls and assessed treatment outcome in patients. METHODS: Ninety detoxified, medication-free, alcohol-dependent patients and 96 age-and gender-matched control subjects underwent functional magnetic resonance imaging during the two-step task. Alcohol expectancies were measured with the Alcohol Expectancy Questionnaire. Over a follow-up period of 48 weeks, 37 patients remained abstinent and 53 patients relapsed as indicated by the Alcohol Timeline Followback method. RESULTS: Patients who relapsed displayed reduced medial prefrontal cortex activation during model-based decision making. Furthermore, high alcohol expectancies were associated with low model-based control in relapsers, while the opposite was observed in abstainers and healthy control subjects. However, reduced model-based control per se was not associated with subsequent relapse. CONCLUSIONS: These findings suggest that poor treatment outcome in alcohol dependence does not simply result from a shift from model-based to model-free control but is instead dependent on the interaction between high drug expectancies and low model-based decision making. Reduced model-based medial prefrontal cortex signatures in those who relapse point to a neural correlate of relapse risk. These observations suggest that therapeutic interventions should target subjective alcohol expectancies. KW - Alcohol dependence KW - Alcohol expectancy KW - Goal-directed control KW - Medial prefrontal cortex KW - Reinforcement learning KW - Treatment outcome Y1 - 2017 U6 - https://doi.org/10.1016/j.biopsych.2017.04.019 SN - 0006-3223 SN - 1873-2402 VL - 82 SP - 847 EP - 856 PB - Elsevier CY - New York ER - TY - CHAP A1 - Schad, Daniel A1 - Juenger, Elisabeth A1 - Sebold, Miriam A1 - Garbusow, Maria A1 - Bernhart, Nadine A1 - Javadi, Amir Homayoun A1 - Zimmermann, Ulrich S. A1 - Smolka, Michael N. A1 - Heinz, Andreas A1 - Rapp, Michael A. A1 - Huys, Quentin J. M. T1 - Smart goals, slow habits? Individual differences in processing speed and working memory capacity moderate the balance between habitual and goal-directed choice behavior T2 - Cognitive processing : international quarterly of cognitive science Y1 - 2014 SN - 1612-4782 SN - 1612-4790 VL - 15 IS - 1 SP - S62 EP - S62 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Deeken, Friederike A1 - Reichert, Markus A1 - Zech, Hilmar A1 - Wenzel, Julia A1 - Wedemeyer, Friederike A1 - Aguilera, Alvaro A1 - Aslan, Acelya A1 - Bach, Patrick A1 - Bahr, Nadja Samia A1 - Ebrahimi, Claudia A1 - Fischbach, Pascale Christine A1 - Ganz, Marvin A1 - Garbusow, Maria A1 - Großkopf, Charlotte M. A1 - Heigert, Marie A1 - Hentschel, Angela A1 - Karl, Damian A1 - Pelz, Patricia A1 - Pinger, Mathieu A1 - Riemerschmid, Carlotta A1 - Rosenthal, Annika A1 - Steffen, Johannes A1 - Strehle, Jens A1 - Weiss,, Franziska A1 - Wieder, Gesine A1 - Wieland, Alfred A1 - Zaiser, Judith A1 - Zimmermann, Sina A1 - Walter, Henrik A1 - Lenz, Bernd A1 - Deserno, Lorenz A1 - Smolka, Michael N. A1 - Liu, Shuyan A1 - Ebner-Priemer, Ulrich Walter A1 - Heinz, Andreas A1 - Rapp, Michael A. T1 - Patterns of Alcohol Consumption Among Individuals With Alcohol Use Disorder During the COVID-19 Pandemic and Lockdowns in Germany JF - JAMA Network Open N2 - Importance Alcohol consumption (AC) leads to death and disability worldwide. Ongoing discussions on potential negative effects of the COVID-19 pandemic on AC need to be informed by real-world evidence. Objective To examine whether lockdown measures are associated with AC and consumption-related temporal and psychological within-person mechanisms. Design, Setting, and Participants This quantitative, intensive, longitudinal cohort study recruited 1743 participants from 3 sites from February 20, 2020, to February 28, 2021. Data were provided before and within the second lockdown of the COVID-19 pandemic in Germany: before lockdown (October 2 to November 1, 2020); light lockdown (November 2 to December 15, 2020); and hard lockdown (December 16, 2020, to February 28, 2021). Main Outcomes and Measures Daily ratings of AC (main outcome) captured during 3 lockdown phases (main variable) and temporal (weekends and holidays) and psychological (social isolation and drinking intention) correlates. Results Of the 1743 screened participants, 189 (119 [63.0%] male; median [IQR] age, 37 [27.5-52.0] years) with at least 2 alcohol use disorder (AUD) criteria according to the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) yet without the need for medically supervised alcohol withdrawal were included. These individuals provided 14 694 smartphone ratings from October 2020 through February 2021. Multilevel modeling revealed significantly higher AC (grams of alcohol per day) on weekend days vs weekdays (β = 11.39; 95% CI, 10.00-12.77; P < .001). Alcohol consumption was above the overall average on Christmas (β = 26.82; 95% CI, 21.87-31.77; P < .001) and New Year’s Eve (β = 66.88; 95% CI, 59.22-74.54; P < .001). During the hard lockdown, perceived social isolation was significantly higher (β = 0.12; 95% CI, 0.06-0.15; P < .001), but AC was significantly lower (β = −5.45; 95% CI, −8.00 to −2.90; P = .001). Independent of lockdown, intention to drink less alcohol was associated with lower AC (β = −11.10; 95% CI, −13.63 to −8.58; P < .001). Notably, differences in AC between weekend and weekdays decreased both during the hard lockdown (β = −6.14; 95% CI, −9.96 to −2.31; P = .002) and in participants with severe AUD (β = −6.26; 95% CI, −10.18 to −2.34; P = .002). Conclusions and Relevance This 5-month cohort study found no immediate negative associations of lockdown measures with overall AC. Rather, weekend-weekday and holiday AC patterns exceeded lockdown effects. Differences in AC between weekend days and weekdays evinced that weekend drinking cycles decreased as a function of AUD severity and lockdown measures, indicating a potential mechanism of losing and regaining control. This finding suggests that temporal patterns and drinking intention constitute promising targets for prevention and intervention, even in high-risk individuals. Y1 - 2022 U6 - https://doi.org/10.1001/jamanetworkopen.2022.24641 SN - 2574-3805 VL - 5 SP - 1 EP - 11 PB - JAMA Network / American Medical Association CY - Chicago, Illinois, USA ET - 8 ER - TY - JOUR A1 - Borchert, Florian A1 - Mock, Andreas A1 - Tomczak, Aurelie A1 - Hügel, Jonas A1 - Alkarkoukly, Samer A1 - Knurr, Alexander A1 - Volckmar, Anna-Lena A1 - Stenzinger, Albrecht A1 - Schirmacher, Peter A1 - Debus, Jürgen A1 - Jäger, Dirk A1 - Longerich, Thomas A1 - Fröhling, Stefan A1 - Eils, Roland A1 - Bougatf, Nina A1 - Sax, Ulrich A1 - Schapranow, Matthieu-Patrick T1 - Knowledge bases and software support for variant interpretation in precision oncology JF - Briefings in bioinformatics N2 - Precision oncology is a rapidly evolving interdisciplinary medical specialty. Comprehensive cancer panels are becoming increasingly available at pathology departments worldwide, creating the urgent need for scalable cancer variant annotation and molecularly informed treatment recommendations. A wealth of mainly academia-driven knowledge bases calls for software tools supporting the multi-step diagnostic process. We derive a comprehensive list of knowledge bases relevant for variant interpretation by a review of existing literature followed by a survey among medical experts from university hospitals in Germany. In addition, we review cancer variant interpretation tools, which integrate multiple knowledge bases. We categorize the knowledge bases along the diagnostic process in precision oncology and analyze programmatic access options as well as the integration of knowledge bases into software tools. The most commonly used knowledge bases provide good programmatic access options and have been integrated into a range of software tools. For the wider set of knowledge bases, access options vary across different parts of the diagnostic process. Programmatic access is limited for information regarding clinical classifications of variants and for therapy recommendations. The main issue for databases used for biological classification of pathogenic variants and pathway context information is the lack of standardized interfaces. There is no single cancer variant interpretation tool that integrates all identified knowledge bases. Specialized tools are available and need to be further developed for different steps in the diagnostic process. KW - HiGHmed KW - personalized medicine KW - molecular tumor board KW - data integration KW - cancer therapy Y1 - 2021 U6 - https://doi.org/10.1093/bib/bbab134 SN - 1467-5463 SN - 1477-4054 VL - 22 IS - 6 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Geier, Stephan A1 - Dorsch, Matti A1 - Pelisoli, Ingrid A1 - Reindl, Nicole A1 - Heber, Ulrich A1 - Irrgang, Andreas T1 - Radial velocity variability and the evolution of hot subdwarf stars JF - Astronomy and astrophysics : an international weekly journal N2 - Hot subdwarf stars represent a late and peculiar stage in the evolution of low-mass stars, since they are likely formed by close binary interactions. In this work, we perform a radial velocity (RV) variability study of a sample of 646 hot subdwarfs with multi-epoch radial velocities based on spectra from Sloan Digital Sky Survey (SDSS) and Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST). The atmospheric parameters and RVs were taken from the literature. For stars with archival spectra but without literature values, we determined the parameters by fitting model atmospheres. In addition, we redetermined the atmospheric parameters and RVs for all the He-enriched sdO/Bs. This broad sample allowed us to study RV-variability as a function of the location in the T-eff - log g- and T-eff - log n(He)/n(H) diagrams in a statistically significant way. We used the fraction of RV-variable stars and the distribution of the maximum RV variations Delta RVmax as diagnostics. Both indicators turned out to be quite inhomogeneous across the studied parameter ranges. A striking feature is the completely dissimilar behaviour of He-poor and He-rich hot subdwarfs. While the former have a high fraction of close binaries, almost no significant RV variations could be detected for the latter. This has led us to the conclusion that there is likely no evolutionary connection between these subtypes. On the other hand, intermediate He-rich- and extreme He-rich sdOB/Os are more likely to be related. Furthermore, we conclude that the vast majority of this population is formed via one or several binary merger channels. Hot subdwarfs with temperatures cooler than similar to 24 000 K tend to show fewer and smaller RV-variations. These objects might constitute a new subpopulation of binaries with longer periods and late-type or compact companions. The RV-variability properties of the extreme horizontal branch (EHB) and corresponding post-EHB populations of the He-poor hot subdwarfs match and confirm the predicted evolutionary connection between them. Stars found below the canonical EHB at somewhat higher surface gravities show large RV variations and a high RV variability fraction. These properties are consistent with most of them being low-mass EHB stars or progenitors of low-mass helium white dwarfs in close binaries. KW - subdwarfs KW - binaries: spectroscopic KW - stars: horizontal-branch Y1 - 2022 U6 - https://doi.org/10.1051/0004-6361/202143022 SN - 0004-6361 SN - 1432-0746 VL - 661 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Schaffenroth, Veronika A1 - Casewell, Sarah L. A1 - Schneider, D. A1 - Kilkenny, David A1 - Geier, Stephan A1 - Heber, Ulrich A1 - Irrgang, Andreas A1 - Przybilla, Norbert A1 - Marsh, Thomas R. A1 - Littlefair, Stuart P. A1 - Dhillon, Vik S. T1 - A quantitative in-depth analysis of the prototype sdB plus BD system SDSS J08205+0008 revisited in the Gaia era JF - Monthly notices of the Royal Astronomical Society N2 - Subdwarf B stars are core-helium-burning stars located on the extreme horizontal branch (EHB). Extensive mass loss on the red giant branch is necessary to form them. It has been proposed that substellar companions could lead to the required mass loss when they are engulfed in the envelope of the red giant star. J08205+0008 was the first example of a hot subdwarf star with a close, substellar companion candidate to be found. Here, we perform an in-depth re-analysis of this important system with much higher quality data allowing additional analysis methods. From the higher resolution spectra obtained with ESO-VLT/XSHOOTER, we derive the chemical abundances of the hot subdwarf as well as its rotational velocity. Using the Gaia parallax and a fit to the spectral energy distribution in the secondary eclipse, tight constraints to the radius of the hot subdwarf are derived. From a long-term photometric campaign, we detected a significant period decrease of -3.2(8) x 10(-12) dd(-1). This can be explained by the non-synchronized hot subdwarf star being spun up by tidal interactions forcing it to become synchronized. From the rate of period decrease we could derive the synchronization time-scale to be 4 Myr, much smaller than the lifetime on EHB. By combining all different methods, we could constrain the hot subdwarf to a mass of 0.39-0.50 M-circle dot and a radius of R-sdB = 0.194 +/- 0.008 R-circle dot, and the companion to 0.061-0.071 M-circle dot with a radius of R-comp = 0.092 +/- 0.005 R-circle dot, below the hydrogen-burning limit. We therefore confirm that the companion is most likely a massive brown dwarf. KW - stars: abundances KW - stars: atmospheres KW - stars: fundamental parameters KW - stars: horizontal branch KW - stars: low-mass KW - subdwarfs Y1 - 2020 U6 - https://doi.org/10.1093/mnras/staa3661 SN - 0035-8711 SN - 1365-2966 VL - 501 IS - 3 SP - 3847 EP - 3870 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Irrgang, Andreas A1 - Geier, Stephan A1 - Kreuzer, Simon A1 - Pelisoli, Ingrid Domingos A1 - Heber, Ulrich T1 - A stripped helium star in the potential black hole binary LB-1 JF - Astronomy and astrophysics : an international weekly journal N2 - Context The recently claimed discovery of a massive (M-BH = 68(-13)(+11) M-circle dot) black hole in the Galactic solar neighborhood has led to controversial discussions because it severely challenges our current view of stellar evolution. Aims A crucial aspect for the determination of the mass of the unseen black hole is the precise nature of its visible companion, the B-type star LSV +22 25. Because stars of different mass can exhibit B-type spectra during the course of their evolution, it is essential to obtain a comprehensive picture of the star to unravel its nature and, thus, its mass. Methods To this end, we study the spectral energy distribution of LSV +22 25 and perform a quantitative spectroscopic analysis that includes the determination of chemical abundances for He, C, N, O, Ne, Mg, Al, Si, S, Ar, and Fe. Results Our analysis clearly shows that LSV +22 25 is not an ordinary main sequence B-type star. The derived abundance pattern exhibits heavy imprints of the CNO bi-cycle of hydrogen burning, that is, He and N are strongly enriched at the expense of C and O. Moreover, the elements Mg, Al, Si, S, Ar, and Fe are systematically underabundant when compared to normal main-sequence B-type stars. We suggest that LSV +22 25 is a stripped helium star and discuss two possible formation scenarios. Combining our photometric and spectroscopic results with the Gaia parallax, we infer a stellar mass of 1.1 +/- 0.5 M-circle dot. Based on the binary system's mass function, this yields a minimum mass of 2-3 M-circle dot for the compact companion, which implies that it may not necessarily be a black hole but a massive neutron- or main sequence star. Conclusions The star LSV +22 25 has become famous for possibly having a very massive black hole companion. However, a closer look reveals that the star itself is a very intriguing object. Further investigations are necessary for complete characterization of this object. KW - stars: abundances KW - stars: chemically peculiar KW - stars: early-type KW - pulsars: individual: LS V+22 25 Y1 - 2020 U6 - https://doi.org/10.1051/0004-6361/201937343 SN - 0004-6361 SN - 1432-0746 VL - 633 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Irrgang, Andreas A1 - Geier, Stephan A1 - Heber, Ulrich A1 - Kupfer, Thomas A1 - Fürst, F. T1 - PG 1610+062: a runaway B star challenging classical ejection mechanisms JF - Astronomy and astrophysics : an international weekly journal N2 - Hypervelocity stars are rare objects, mostly main-sequence (MS) B stars, traveling so fast that they will eventually escape from the Milky Way. Recently, it has been shown that the popular Hills mechanism, in which a binary system is disrupted via a close encounter with the supermassive black hole at the Galactic center, may not be their only ejection mechanism. The analyses of Gaia data ruled out a Galactic center origin for some of them, and instead indicated that they are extreme disk runaway stars ejected at velocities exceeding the predicted limits of classical scenarios (dynamical ejection from star clusters or binary supernova ejection). We present the discovery of a new extreme disk runaway star, PG 1610+062, which is a slowly pulsating B star bright enough to be studied in detail. A quantitative analysis of spectra taken with ESI at the Keck Observatory revealed that PG 1610+062 is a late B-type MS star of 4–5 M⊙ with low projected rotational velocity. Abundances (C, N, O, Ne, Mg, Al, Si, S, Ar, and Fe) were derived differentially with respect to the normal B star HD 137366 and indicate that PG 1610+062 is somewhat metal rich. A kinematic analysis, based on our spectrophotometric distance (17.3 kpc) and on proper motions from Gaia’s second data release, shows that PG 1610+062 was probably ejected from the Carina-Sagittarius spiral arm at a velocity of 550 ± 40 km s−1, which is beyond the classical limits. Accordingly, the star is in the top five of the most extreme MS disk runaway stars and is only the second among the five for which the chemical composition is known. KW - stars: abundances KW - stars: individual: HD 137366 KW - stars: kinematics and dynamics KW - stars: individual: PG 1610+062 KW - stars: early-type Y1 - 2019 U6 - https://doi.org/10.1051/0004-6361/201935429 SN - 1432-0746 VL - 628 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Zech, Hilmar G. A1 - Reichert, Markus A1 - Ebner-Priemer, Ulrich W. A1 - Tost, Heike A1 - Rapp, Michael A. A1 - Heinz, Andreas A1 - Dolan, Raymond J. A1 - Smolka, Michael N. A1 - Deserno, Lorenz T1 - Mobile data collection of cognitive-behavioral tasks in substance use disorders: Where are we now? JF - Neuropsychobiology N2 - Introduction: Over the last decades, our understanding of the cognitive, motivational, and neural processes involved in addictive behavior has increased enormously. A plethora of laboratory-based and cross-sectional studies has linked cognitive-behavioral measures to between-subject differences in drinking behavior. However, such laboratory-based studies inevitably suffer from small sample sizes and the inability to link temporal fluctuations in task measures to fluctuations in real-life substance use. To overcome these problems, several existing behavioral tasks have been transferred to smartphones to allow studying cognition in the field. Method: In this narrative review, we first summarize studies that used existing behavioral tasks in the laboratory and self-reports of substance use with ecological momentary assessment (EMA) in the field. Next, we review studies on psychometric properties of smartphone-based behavioral tasks. Finally, we review studies that used both smartphone-based tasks and self-reports with EMA in the field. Results: Overall, studies were scarce and heterogenous both in tasks and in study outcomes. Nevertheless, existing findings are promising and point toward several methodological recommendations: concerning psychometrics, studies show that - although more systematic studies are necessary - task validity and reliability can be improved, for example, by analyzing several measurement sessions at once rather than analyzing sessions separately. Studies that use tasks in the field, moreover, show that power can be improved by choosing sampling schemes that combine time-based with event-based sampling, rather than relying on time-based sampling alone. Increasing sampling frequency can further increase power. However, as this also increases the burden to participants, more research is necessary to determine the ideal sampling frequency for each task. Conclusion: Although more research is necessary to systematically study both the psychometrics of smartphone-based tasks and the frequency at which task measures fluctuate, existing studies are promising and reveal important methodological recommendations useful for researchers interested in implementing behavioral tasks in EMA studies. KW - Ecological momentary assessment KW - Behavioral tasks KW - Smartphone KW - Substance use KW - Addiction Y1 - 2022 U6 - https://doi.org/10.1159/000523697 SN - 0302-282X SN - 1423-0224 VL - 81 IS - 5 SP - 438 EP - 450 PB - Karger CY - Basel ER -