Identification of the current path for a conductive molecular wire on a tripodal platform

We present the chemical synthesis as well as charge transport measurements and calculations for a new tripodal platform based on a rigid 9,9′-spirobifluorene equipped with a phenylene-ethynylene wire. The transport experiments are performed with the help of the low-temperature mechanically controlled break junction technique with gold electrodes. By combining experimental and theoretical investigations of elastic and inelastic charge transport, we show that the current proceeds through the designated molecular wire and identify a binding geometry that is compatible with the experimental observations. The conductive molecular wire on the platform features a well-defined and relatively high conductance of the order of 10 −3 G 0 despite the length of the current path of more than 1.7 nm, demonstrating that this platform is suitable to incorporate functional units like molecular switches or sensors

Untersuchungen zur Herstellung und zum Abbrandverhalten von Wirbelschichtpyrolysekoksen

Der partielle und selektive Abbrand von Pyrolysekoksen in einem Wirbelbett mit Steinkohlekoks als Bettmaterial könnte die benötigte Wärme erzeugen, um in demselben Reaktor endotherme Pyrolyse- und Vergasungsreaktionen zur Behandlung organischer Reststoffe durchzuführen. Zur Messung der Reaktivitätsunterschiede der Kokse bezüglich Sauerstoff wurde an zwei Laborapparaturen (Thermowaage, Sandwirbelschicht) das Abbrandverhalten von Wirbelschicht-Pyrolysekoksen und Kohlekoksen im chemisch kontrollierten Temperaturbereich untersucht. Zur Bestimmung der formalkinetischen Parameter Aktivierungsenergie EA und Stoßfaktor k0 wurde im Falle der Thermowaage die Massenverlustkurve bei isothermer Reaktionführung ausgewertet. Im Falle der Wirbelschicht wurde der zeitliche CO/ CO2\- Verlauf im Abgas in eine Massenverlustkurve an Kohlenstoff umgerechnet und anschließend analog zur Thermowaage ausgewertet. Zur Beschreibung der Kinetik wurde ein massenbezogener Ansatz erster Ordnung bezüglich der Kohlenstoffmasse und -ter Ordnung bezüglich der Sauerstoffkonzentration verwendet. Die an der Thermowaage bestimmten Reaktivitäten der Kokse werden vergleichend in einem Arrhenius-Diagramm (T=250-600°C) dargestellt. Nach steigender Reaktivität geordnet lautet die Reihenfolge der untersuchten Kokse: Steinkohlenkoks < Braunkohlenkoks < DSD-Koks < Holzkoks < Strohkoks. Durch die an der Thermowaage bestimmten Reaktivitätsunterschiede zwischen Pyrolysekoksen und Bettmaterial ist ein selektiver Abbrand der Pyrolysekokse beim Betrieb einer kontinuierlichen Kokswirbelschicht zu erwarten

Energy demand and efficiency measures in polymer processing: comparison between temperate and Mediterranean operating plants

Polymer processing is an energy-intensive industry. The plastification of polymers requires a high volume of electric power for thermal energy. Electricity based power is the common form of energy in polymer processing and provides obvious potential for a reduction in energy use and costs. Measures to avoid production-based conversion losses, total conversion and transportation losses in energy used all have social, national, economic and business relevance. A bottom-up evaluation of four different production factories in this study assesses the potential for energy use improvements. The resulting theoretical assessment suggested that reducing primary energy demand is the most powerful target for reducing energy intensity in the polymer industry followed by the introduction of improved technologies to raise energy efficiency. The transferability of the conclusions was supported by the comparison between two different geographic locations for polymer production in Germany and Western Australia. The findings of this research suggest potential in their use in ‘green’ decision-making in the plastics industry

Automated identification of diagnostic labelling errors in medicine

Objectives: Identification of diagnostic error is complex and mostly relies on expert ratings, a severely limited procedure. We developed a system that allows to automatically identify diagnostic labelling error from diagnoses coded according to the international classification of diseases (ICD), often available as routine health care data. Methods: The system developed (index test) was validated against rater based classifications taken from three previous studies of diagnostic labeling error (reference standard). The system compares pairs of diagnoses through calculation of their distance within the ICD taxonomy. Calculation is based on four different algorithms. To assess the concordance between index test and reference standard, we calculated the area under the receiver operating characteristics curve (AUROC) and corresponding confidence intervals. Analysis were conducted overall and separately per algorithm and type of available dataset. Results: Diagnoses of 1,127 cases were analyzed. Raters previously classified 24.58% of cases as diagnostic labelling errors (ranging from 12.3 to 87.2% in the three datasets). AUROC ranged between 0.821 and 0.837 overall, depending on the algorithm used to calculate the index test (95% CIs ranging from 0.8 to 0.86). Analyzed per type of dataset separately, the highest AUROC was 0.924 (95% CI 0.887-0.962). Conclusions: The trigger system to automatically identify diagnostic labeling error from routine health care data performs excellent, and is unaffected by the reference standards' limitations. It is however only applicable to cases with pairs of diagnoses, of which one must be more accurate or otherwise superior than the other, reflecting a prevalent definition of a diagnostic labeling error

Cluster-based density-functional approach to quantum transport through molecular and atomic contacts

We present a cluster-based density-functional approach to model charge transport through molecular and atomic contacts. The electronic structure of the contacts is determined in the framework of density functional theory, and the parameters needed to describe transport are extracted from finite clusters. A similar procedure, restricted to nearest-neighbor interactions in the electrodes, has been presented by Damle et al. [Chem. Phys. 281, 171 (2002)]. Here, we show how to systematically improve the description of the electrodes by extracting bulk parameters from sufficiently large metal clusters. In this way we avoid problems arising from the use of nonorthogonal basis functions. For demonstration we apply our method to electron transport through Au contacts with various atomic-chain configurations and to a single-atom contact of Al.Comment: 18 pages, 13 figure

PARP1 catalytic variants reveal branching and chain length-specific functions of poly(ADP-ribose) in cellular physiology and stress response

Poly(ADP-ribosyl)ation regulates numerous cellular processes like genome maintenance and cell death, thus providing protective functions but also contributing to several pathological conditions. Poly(ADP-ribose) (PAR) molecules exhibit a remarkable heterogeneity in chain lengths and branching frequencies, but the biological significance of this is basically unknown. To unravel structure-specific functions of PAR, we used PARP1 mutants producing PAR of different qualities, i.e. short and hypobranched (PARP1\G972R), short and moderately hyperbranched (PARP1\Y986S), or strongly hyperbranched PAR (PARP1\Y986H). By reconstituting HeLa PARP1 knockout cells, we demonstrate that PARP1\G972R negatively affects cellular endpoints, such as viability, cell cycle progression and genotoxic stress resistance. In contrast, PARP1\Y986S elicits only mild effects, suggesting that PAR branching compensates for short polymer length. Interestingly, PARP1\Y986H exhibits moderate beneficial effects on cell physiology. Furthermore, different PARP1 mutants have distinct effects on molecular processes, such as gene expression and protein localization dynamics of PARP1 itself, and of its downstream factor XRCC1. Finally, the biological relevance of PAR branching is emphasized by the fact that branching frequencies vary considerably during different phases of the DNA damage-induced PARylation reaction and between different mouse tissues. Taken together, this study reveals that PAR branching and chain length essentially affect cellular functions, which further supports the notion of a ‘PAR code’

Repetitive Exposure to Bacteriophage Cocktails against Pseudomonas aeruginosa or Escherichia coli Provokes Marginal Humoral Immunity in Naïve Mice

Phage therapy of ventilator-associated pneumonia (VAP) is of great interest due to the rising incidence of multidrug-resistant bacterial pathogens. However, natural or therapy-induced immunity against therapeutic phages remains a potential concern. In this study, we investigated the innate and adaptive immune responses to two different phage cocktails targeting either Pseudomonas aeruginosa or Escherichia coli—two VAP-associated pathogens—in naïve mice without the confounding effects of a bacterial infection. Active or UV-inactivated phage cocktails or buffers were injected intraperitoneally daily for 7 days in C57BL/6J wild-type mice. Blood cell analysis, flow cytometry analysis, assessment of phage distribution and histopathological analysis of spleens were performed at 6 h, 10 days and 21 days after treatment start. Phages reached the lungs and although the phage cocktails were slightly immunogenic, phage injections were well tolerated without obvious adverse effects. No signs of activation of innate or adaptive immune cells were observed; however, both active phage cocktails elicited a minimal humoral response with secretion of phage-specific antibodies. Our findings show that even repetitive injections lead only to a minimal innate and adaptive immune response in naïve mice and suggest that systemic phage treatment is thus potentially suitable for treating bacterial lung infections