Neurosecretion and metamorphosis in the milkweed bug,Oncopeltus fasciatus (Dallas)

Zusammenfassung Exstirpation der 10 neurosekretorischenA-Zellen der Pars intercerebralis führt beiOncopeltus nicht zum Ausfall der letzten Larvenhäutung. Es wird angenommen, dass das Neurosekret derA-Zellen, welches in der Aortenwand gespeichert wird, die Häutung ermöglicht.     

Quantum annealing with manufactured spins

Many interesting but practically intractable problems can be reduced to that of finding the ground state of a system of interacting spins; however, finding such a ground state remains computationally difficult. It is believed that the ground state of some naturally occurring spin systems can be effectively attained through a process called quantum annealing. If it could be harnessed, quantum annealing might improve on known methods for solving certain types of problem. However, physical investigation of quantum annealing has been largely confined to microscopic spins in condensed-matter systems. Here we use quantum annealing to find the ground state of an artificial Ising spin system comprising an array of eight superconducting flux quantum bits with programmable spin-spin couplings. We observe a clear signature of quantum annealing, distinguishable from classical thermal annealing through the temperature dependence of the time at which the system dynamics freezes. Our implementation can be configured in situ to realize a wide variety of different spin networks, each of which can be monitored as it moves towards a low-energy configuration. This programmable artificial spin network bridges the gap between the theoretical study of ideal isolated spin networks and the experimental investigation of bulk magnetic samples. Moreover, with an increased number of spins, such a system may provide a practical physical means to implement a quantum algorithm, possibly allowing more-effective approaches to solving certain classes of hard combinatorial optimization problems.     

Composition and functional role of the mucus layers in the intestine

In discussions on intestinal protection, the protective capacity of mucus has not been very much considered. The progress in the last years in understanding the molecular nature of mucins, the main building blocks of mucus, has, however, changed this. The intestinal enterocytes have their apical surfaces covered by transmembrane mucins and the whole intestinal surface is further covered by mucus, built around the gel-forming mucin MUC2. The mucus of the small intestine has only one layer, whereas the large intestine has a two-layered mucus where the inner, attached layer has a protective function for the intestine, as it is impermeable to the luminal bacteria.     

Sucrose-gap recording of electrical and mechanical activity in the smooth muscle of the isolated metacarpal vein of the bat

Zusammenfassung Die isolierte pulsatile Flughaut-Vene der Fledermäuse zeigt mit dem «Sucrose-gap» eine enge elektro-mechanische Korrelation. Das AP ist oft von einem Schrittmacher-Potential eingeleitet. Solche AP sind äusserst selten bei den Gefässmuskeln.

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This study was supported by grants from the Swedish Medical Research Council (28-14 x), the G. and A. Claraz-Schenkung and the Swiss National Scientific Research Funds, and was carried out in the Department of Physiology, University of Lund, Sweden.