Five new nonsymmetric 1-diphenylphosphino-3-{bisarylphosphino}propane ligands 1b−f aryl: b = 3,5-bis(trifluoromethyl)phenyl, c = 3,5-dimethylphenyl, d = 3,5-difluorophenyl, e = ...2-(trifluoromethyl)phenyl, f = 2,4,6-trifluorophenyl and their corresponding neutral dichloro palladium(II) 2b−f, diiodo palladium(II) 3d,e, and dicationic diacetonitrile palladium(II) ditetrafluoroborate complexes 4b−f were synthesized. The symmetric ligand 1,3-bis{bis3,5-bis(trifluoromethyl)phenylphosphino}propane (1a) and the related palladium(II) complexes 2a and 4a were prepared for comparison. Solid state structures of new ligands were determined by X-ray structure analysis in the form of the dichloro (2a−c,f) and diiodo (3d,e) compounds. The properties of the symmetric (4a) and nonsymmetric catalysts (4b−f) were tested in propene/CO copolymerization experiments. A clear correlation between primarily steric effects of these ligands and the catalyst activity as well as the molecular weight of the resulting polyketone materials was observed. The nonsymmetric structure 4b, bearing CF3 groups in the 3,5-position of two aryl units on one phosphorus side, proved to be the most effective catalyst, which reached an activity maximum (12.7 kgmol(Pd) × h-1) and led at the same time to propene/CO copolymers of high molecular weight (M̄ w ≈ 5 × 105 g mol-1). The same catalyst species 4b affords even ultrahigh molecular weight ethene/propene/CO terpolymers with M̄ w ≈ 8 × 105 g mol-1. These novel polyketones possess a predominantly regioirregular microstructure, leading to interesting flexible material properties in contrast to already known regioregular and thereby brittle propene/CO copolymers.
Wireless industrial environments are dominated by multipath propagation and interference. In order to handle spatial diversity, a possible approach is dividing the physical area into many small ...cells. The spatial diversity is turned into FDMA by utilizing different frequency bands for neighboring cells. A challenging use case with fast vehicles traveling over long distances in a short time is the packaging industry. It would require many fast handoffs for each vehicle. Thus, a small cell FDMA approach is not appropriate. Conversely, employing radiating lines eliminates FDMA-based handoff issues, and reduces multipath delay spread and signal attenuation compared to centralized approaches. Additionally, radiating lines perform well in high-speed, low-power and long-range environments. In this paper, we realize a novel radiating-line-based, high-reliable, real-time transmission system with near-field coupling. This wireless transmission method results in a frequency-flat, time-invariant radio channel for the given requirements. Employing antenna diversity results in significant improvements in the system's performance compared to single antenna solutions.
A method to optimize the polymerization conditions in order to favor chain propagation is described for the synthesis of polymers containing low reactive, long, linear 1‐olefins and carbon monoxide ...(CO). It consists of the use of the olefin monomer as the polymerization solvent, together with the emulsification of a carefully chosen immiscible activator. This is given as a general method applicable to different families of catalyst able to produce 1,4‐polyketones. When the catalyst precursor is dpppPd(NCCH3)2(BF4)2, which has been extensively studied, the polymerization degrees are the highest published (up to 2.4 × 105 g · mol−1). The influence of parameters like temperature, CO pressure, volume of activator, and catalyst counter ion or ligand substitutions are reported. Some chemical and physical properties of the polymers, such as glass transition temperature, melting processes, and mechanical behavior, are examined and compared with the linear 1‐olefin homologues from C3 to C10. These properties are shown in some cases to be unprecedented.
DSC profiles from the 1st scan for α‐olefin/CO copolymers.
In industrial environments an increasing amount of wireless devices are used, which utilize licence-free bands. As a consequence of this mutual interferences of wireless systems might decrease the ...state of coexistence. Therefore, a central coexistence management system is needed, which allocates conflict-free resources to wireless systems. To ensure a conflict-free resource utilization, it is useful to predict the prospective medium utilisation before resources are allocated. This paper presents a self learning concept, which is based on reinforcement learning. A simulative evaluation of reinforcement learning agents based on neural networks, called deep Q-networks and double deep Q-networks, was realised for exemplary and practically relevant coexistence scenarios. The evaluation of the double deep Q-network showed, that a prediction accuracy of at least 98 % can be reached in all investigated scenarios.
Migraine is the most common neurological disorder and can be associated with a high degree of disability. In addition to non-pharmacological approaches to reduce migraine frequency, pharmacological ...migraine preventatives are available. Evidence-based guidelines from the German Migraine and Headache Society (DMKG), and German Society for Neurology (DGN), Austrian Headache Society (ÖKSG), and Swiss Headache Society (SKG) are available for indication and application. For therapy-relevant questions such as the duration of a pharmacological migraine prevention, no conclusions can be drawn from currently available study data. The aim of this review is to present a therapy consensus statement that integrates the current data situation and, where data are lacking, expert opinions. The resulting current recommendations on the duration of therapy for pharmacological migraine prophylaxis are shown here.
Zusammenfassung
Migräne ist die häufigste neurologische Erkrankung und kann mit einem hohen Grad der Beeinträchtigung einhergehen. Neben nichtmedikamentösen Ansätzen zur Reduktion der Migränefrequenz ...stehen medikamentöse Migräneprophylaxen zur Verfügung. Zur Indikation und Anwendung liegen evidenzbasierte Leitlinien der Deutschen Migräne- und Kopfschmerzgesellschaft (DMKG) und Deutschen Gesellschaft für Neurologie (DGN), Österreichischen Kopfschmerzgesellschaft (ÖKSG) sowie Schweizer Kopfwehgesellschaft (SKG) vor. Für therapierelevante Fragen wie z. B. der notwendigen und sinnvollen Dauer einer medikamentösen Migräneprophylaxe können aus bisherigen Studiendaten keine Rückschlüsse gezogen werden. Ziel dieser Übersicht ist die Formulierung von Empfehlungen zur Therapiedauer bei wirksamer medikamentöser Migräneprophylaxe, die die aktuelle Datenlage und – bei fehlenden Daten – die Expertenmeinungen berücksichtigen.
Migraine is the most common neurological disorder and can be associated with a high degree of disability. In addition to non-pharmacological approaches to reduce migraine frequency, pharmacological ...migraine preventatives are available. Evidence-based guidelines from the German Migraine and Headache Society (DMKG), and German Society for Neurology (DGN), Austrian Headache Society (ÖKSG), and Swiss Headache Society (SKG) are available for indication and application. For therapy-relevant questions such as the duration of a pharmacological migraine prevention, no conclusions can be drawn from currently available study data. The aim of this review is to present a therapy consensus statement that integrates the current data situation and, where data are lacking, expert opinions. The resulting current recommendations on the duration of therapy for pharmacological migraine prophylaxis are shown here.
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