Coupling mechanisms between the contralateral legs of a walking insect (Carausius morosus)

Cruse H, Knauth A. Coupling mechanisms between the contralateral legs of a walking insect (Carausius morosus). The journal of experimental biology. 1989;144(1):199-213.Interactions between contralateral legs of stick insects during walking were examined in the absence of mechanical coupling between the legs by studying animals walking on a horizontal plane covered with a thin film of silicone oil. Investigations of undisturbed walks showed that contralateral coupling is weaker han ipsilateral coupling. Two types of influence were found, (i) For each pair of front, middle and rear legs, when one leg started a retraction movement, the probability for the contralateral leg to start a protraction was increased, (ii) For front- and hind-leg pairs, it was found that the probability of starting a protraction in one leg was also increased, the farther the other leg was moved backwards during retraction. Whether such influences exist between middle legs could not be determined. Both ‘excitatory’ mechanisms very much resemble those influences which have been found to exist between ipsilateral legs. However, in contrast to ipsilateral legs, the interaction between two contralateral legs was found to act in both directions

The Interstellar N/O Abundance Ratio: Evidence for Local Infall?

Sensitive measurements of the interstellar gas-phase oxygen abundance have revealed a slight oxygen deficiency ($\sim$ 15%) toward stars within 500 pc of the Sun as compared to more distant sightlines. Recent $FUSE$ observations of the interstellar gas-phase nitrogen abundance indicate larger variations, but no trends with distance were reported due to the significant measurement uncertainties for many sightlines. By considering only the highest quality ($\geq$ 5 $\sigma$) N/O abundance measurements, we find an intriguing trend in the interstellar N/O ratio with distance. Toward the seven stars within $\sim$ 500 pc of the Sun, the weighted mean N/O ratio is 0.217 $\pm$ 0.011, while for the six stars further away the weighted mean value (N/O = 0.142 $\pm$ 0.008) is curiously consistent with the current Solar value (N/O = 0.138$^{+0.20}_{-0.18}$). It is difficult to imagine a scenario invoking environmental (e.g., dust depletion, ionization, etc.) variations alone that explains this abundance anomaly. Is the enhanced nitrogen abundance localized to the Solar neighborhood or evidence of a more widespread phenomenon? If it is localized, then recent infall of low metallicity gas in the Solar neighborhood may be the best explanation. Otherwise, the N/O variations may be best explained by large-scale differences in the interstellar mixing processes for AGB stars and Type II supernovae.Comment: accepted for publication in the Astrophysical Journal Letter

Vergleich von Antibeschlagmethoden in der Endoskopie: Was wirklich hilft

Zusammenfassung: Hintergrund und Fragestellung: Endoskopische Verfahren, wie die fiberoptische Intubation, haben sich als Standard in der Anästhesie etabliert. Obwohl allgemein bekannt ist, dass zur sicheren Anwendung von Endoskopen eine Antibeschlagmethode unerlässlich ist, fehlen Studien zum Vergleich der Wirksamkeit verschiedener Antibeschlagmethoden. Ziel dieser Studie war es, die Wirksamkeit von 7Antibeschlagmethoden im Einsatz mit einem flexiblen und einem starren Endoskop zu untersuchen. Material und Methoden: Die Wirksamkeit von je 2Antibeschlaglösungen und -tüchern, einem induktiven Endoskopvorwärmer, sowie kontinuierlichem Sauerstofffluss über den Arbeitskanal der Optik wurde in einem Atemwegsmodell mithilfe eines flexiblen und eines starren Endoskops getestet sowie verblindet beurteilt. Ergebnisse: Insgesamt wurden 300Testbilder aufgezeichnet und analysiert. Sowohl in der Gruppe mit dem flexiblen als auch in der Gruppe mit dem starren Endoskop erzielten je eine Antibeschlaglösung und ein -tuch die besten Ergebnisse. Flexible Endoskopie: Anti-Fog (Versagerquote: 3%), Lina Clear (4%). Starre Endoskopie: Ultrastop (5%), Lina Clear (3,5%). Der Endoskopvorwärmer mit 2-maliger Anwendung zeigte in beiden Gruppen sehr gute Ergebnisse (6% und 10%). Keinen positiven Effekt gegen das Beschlagen eines Endoskops ergab die Verwendung des Sauerstoffflusses (93,5%). Schlussfolgerungen: Die Studie konnte aufzeigen, dass es Unterschiede in der Effektivität von Antibeschlagtüchern und -lösungen gibt. Der klinische Einsatz ist aber auch von weiteren Faktoren wie Endoskoptyp und Häufigkeit der Verwendung, Kosten- und Hygieneaspekten abhängig. Der induktive Endoskopvorwärmer kann trotz hoher Anschaffungskosten eine Alternative darstellen. Jedoch fehlen bislang klare Sicherheitshinweise zur mehrfachen Anwendung durch den Hersteller. Der kontinuierliche Sauerstofffluss über den Arbeitskanal einer flexiblen Optik kann nicht als Antibeschlagmethode empfohlen werde

Cu/Ni/Au multilayers by electrochemistry: A crucial system in electronics - A critical review

International audienc

Sol–gel synthesis, X-ray photoelectron spectroscopy and electrical conductivity of Co-doped (La, Sr)(Ga, Mg)O3−δ perovskites

La0.8Sr0.2Ga0.8Mg0.2−xCoxO3−δ (LSGMC) powders containing different amounts of Co (x = 0.05 and 0.085) were prepared by a citrate sol–gel method. The powders were used to prepare highly phase-pure LSGMC sintered pellets with controlled composition and fractional densities larger than 95%. For the first time, LSGMC materials were subjected to X-ray photoelectron spectroscopy (XPS) characterization. XPS data confirmed the presence of the dopants in the material and allowed to identify two different chemical states for Sr2+ and oxygen, both related to the oxygen-deficient perovskite structure of LSGMC. The conductivity of LSGMC sintered pellets containing different amounts of Co ions in the B sites of the perovskite lattice was assessed by electrochemical impedance spectroscopy (EIS) in the 250–750 °C temperature range. Conductivity values and apparent activation energies were in good agreement with previously published data referring to materials with same composition, but prepared by solid-state route. Therefore, the physicochemical and electrochemical characterization clearly demonstrated the ability of sol–gel methods to produce high-purity Co-doped LSGM perovskites, which represent promising solid electrolytes for intermediate-temperature SOFCs

Single-step electrodeposition of superhydrophobic black NiO thin films

International audienceBlack finished surfaces have extensive applications in many domains, such as optics, solar cells, and aerospace. The single step electrodeposition of superhydrophobic black NiO films from a dimethyl sulfoxide based electrolyte is described in this paper. The physicochemical properties of the obtained film were characterized using Scanning Electron Microscopy, X-ray Diffraction, and electrochemical tests (Electrochemical Impedance Spectroscopy and potentiodynamic polarization). A rough surface with a low reflection of light was formed after the deposition process that increased the contact angle of water from about 87º (for bare Cu) to 163º (in presence of the black coating), which improved the corrosion resistance of the Cu substrate by about 30%. The formed black NiO film revealed a notably high stability and kept its appearance even after corrosion tests

Deposition of earth-abundant p-type CuBr films with high hole conductivity and realization of p-CuBr/n-Si heterojunction solar cell

We present details of the deposition of transparent and earth-abundant p-type CuBr films with high hole conductivity and the fabrication and characterization of a prototype solar cell based on p-CuBr/n-Si heterojunctions. p-type CuBr films with typical resistivities and hole concentrations of 7×10-1 Ωcm and 7.5×1019 cm-3, respectively, are deposited by thermal evaporation followed by oxygen plasma treatment. The transparent p-type films show strong room temperature photoluminescence at ~2.97 eV. The current voltage (I-V) characteristics of the heterojunctions show good diode behaviour. Power conversion efficiency of ~ 2 % was achieved for the heterojunction device without any optimization of the cell structure under AM 1.5 illumination condition with a short circuit current (Jsc) and open circuit voltage (Voc) of 13.2 mA/cm2 and 0.44 V, respectively