The effect of boron doping into Co-C-N and Fe-C-N electrocatalysts on the oxygen reduction reaction

Co-C-N and Fe-C-N thin film catalysts have been modified by controlled doping with boron. Corresponding novel thin film catalysts Co-C-N-B and Fe-C-N-B were synthesized by combinatorial magnetron sputter deposition in an Ar/N₂ gas mixture followed by subsequent heat-treatment between 700 and 1000 °C in an argon atmosphere. The nitrogen content of the as-prepared thin film catalysts could be increased by the addition of boron. Furthermore, the amount of remaining nitrogen in heat-treated catalyst samples was significantly higher in case of boron containing samples. The thin film catalysts were characterized by means of X-ray diffraction (XRD) analysis, electron microprobe and electrochemical measurements. For electrochemical studies the activity as oxygen reduction reaction (ORR) catalyst was investigated using the rotating ring-disk electrode (RRDE) technique in 0.1 M HClO₄ solution at room temperature. The catalytic activity was found to decrease with the boron content in the thin film catalysts even though the N-content increased.     

纽马格推动客户BCF生产

地毯和地毯纱市场总是充满着挑战,新的需求不断地出现。地毯业的时尚潮流在快速地变化着,同时全球性的压力也在稳步增长。地毯业在这样的竞争环境中必须找到能够保持成功的途径。在这种情况下．工艺链前期的BCF技术对地毯纱和地毯生产是否成功起着决定性的作用。     

The Functional Characterization of GCaMP3.0 Variants Specifically Targeted to Subcellular Domains

Calcium (Ca²⁺) ions play a pivotal role in physiology and cellular signaling. The intracellular Ca²⁺ concentration ([Ca²⁺]_i) is about three orders of magnitude lower than the extracellular concentration, resulting in a steep transmembrane concentration gradient. Thus, the spatial and the temporal dynamics of [Ca²⁺]_i are ideally suited to modulate Ca²⁺-mediated cellular responses to external signals. A variety of highly sophisticated methods have been developed to gain insight into cellular Ca²⁺ dynamics. In addition to electrophysiological measurements and the application of synthetic dyes that change their fluorescent properties upon interaction with Ca²⁺, the introduction and the ongoing development of genetically encoded Ca²⁺ indicators (GECI) opened a new era to study Ca²⁺-driven processes in living cells and organisms. Here, we have focused on one well-established GECI, i.e., GCaMP3.0. We have systematically modified the protein with sequence motifs, allowing localization of the sensor in the nucleus, in the mitochondrial matrix, at the mitochondrial outer membrane, and at the plasma membrane. The individual variants and a cytosolic version of GCaMP3.0 were overexpressed and purified from E. coli cells to study their biophysical properties in solution. All versions were examined to monitor Ca²⁺ signaling in stably transfected cell lines and in primary cortical neurons transduced with recombinant Adeno-associated viruses (rAAV). In this comparative study, we provide evidence for a robust approach to reliably trace Ca²⁺ signals at the (sub)-cellular level with pronounced temporal resolution.     

Die Sterbehilfedebatte und das Bild der Palliativmedizin in deutschen Printmedien

Background In Germany the discussion about euthanasia and physician assisted suicide is prevalent in the media. This study will analyse the way German newspapers represent the discussion about the end of life and how they report about palliative medicine. Methods A qualitative data analysis was performed of 433 articles published in the years 2006 and 2007 in different German newspapers. The archives of the selected newspapers were searched for “palliative medicine”, “hospice”, “patient’s autonomy”, “patient’s will”, “euthanasia” and “terminal care”. Results Dignity, autonomy, inadequate provision of care and uncertainties were identified as the major topics in the debate about euthanasia. Dignity was used both as an argument for and against legislation of euthanasia. The terminology on euthanasia is not used consistently in Germany. Palliative medicine is described as a possible alternative to euthanasia which should be developed and reimbursed better. Conclusion These findings underline the importance of dignity and autonomy for the public opinion on the end of life. The media show the potential of palliative medicine as an alternative to euthanasia but claim further development of palliative care. The inconsistencies in terminology as well as in the content of end of life decisions have to be clarified to allow an objective discussion. Politicians and the medical profession should know about the public statements and opinions, to react adequately to patient’s fears and allowances.     

A compositional modelling and analysis framework for stochastic hybrid systems

The theory of hybrid systems is well-established as a model for real-world systems consisting of continuous behaviour and discrete control. In practice, the behaviour of such systems is also subject to uncertainties, such as measurement errors, or is controlled by randomised algorithms. These aspects can be modelled and analysed using stochastic hybrid systems. In this paper, we present HModest, an extension to the Modest modelling language—which is originally designed for stochastic timed systems without complex continuous aspects—that adds differential equations and inclusions as an expressive way to describe the continuous system evolution. Modest is a high-level language inspired by classical process algebras, thus compositional modelling is an integral feature. We define the syntax and semantics of HModest and show that it is a conservative extension of Modest that retains the compositional modelling approach. To allow the analysis of HModest models, we report on the implementation of a connection to recently developed tools for the safety verification of stochastic hybrid systems, and illustrate the language and the tool support with a set of small, but instructive case studies.     

Dehydrogenation of 1,3-cyclohexadiene photocatalyzed by osmocene

Osmocene acts as a photocatalyst for the dehydrogenation of 1,3-cyclohexadiene which yields benzene and hydrogen. It is suggested that the primary photochemical step is an electron transfer from the excited osmocene to the diene.     

Reservoir organic geochemistry: Processes and applications

This Special Issue of the “Journal of Petroleum Science and Engineering” is devoted to organic geochemistry and published in honor of Dr Alain-Yves Huc. Alain has been involved in promoting and developing reservoir geochemistry as a tool in the field development and exploitation problem solving toolbox. This volume includes general papers on the potential interest of organic geochemistry for production purposes and discusses some physical processes such as hydrocarbon/water interactions and TSR (Thermochemical Sulfate Reduction). It presents new analytical techniques and shows industrial field applications, demonstrating the potential contribution of organic geochemistry in enhancing hydrocarbon production.     

Optimal control in non-convex domains: a priori discretization error estimates

Abstract An optimal control problem for a two-dimensional elliptic equation with pointwise control constraints is investigated. The domain is assumed to be polygonal but non-convex. The corner singularities are treated by a priori mesh grading. Approximations of the optimal solution of the continuous optimal control problem are constructed by a projection of the discrete adjoint state. It is proved that these approximations have convergence order h². Keywords Linear-quadratic optimal control problems, error estimates, elliptic equations, non-convex domains, corner singularities, control constraints, superconvergence. Mathematics Subject Classification (2000): 49K20, 49M25, 65N30, 65N50