Mechanisms of membrane processes, electric gene transfer and cell fusion Report on the workshop held at the Zentrum für Interdisziplinäre Forschung in Bielefeld on 3–4 April 1986

Dorfmüller T, Förster W, Neumann E. Mechanisms of membrane processes, electric gene transfer and cell fusion Report on the workshop held at the Zentrum für Interdisziplinäre Forschung in Bielefeld on 3–4 April 1986. Bioelectrochemistry and Bioenergetics. 1987;17(1):7-8

3D optical Yagi–Uda nanoantenna array

Future photonic circuits with the capability of high-speed data processing at optical frequencies will rely on the implementation of efficient emitters and detectors on the nanoscale. Towards this goal, bridging the size mismatch between optical radiation and subwavelength emitters or detectors by optical nanoantennas is a subject of current research in the field of plasmonics. Here we introduce an array of three-dimensional optical Yagi–Uda antennas, fabricated using top-down fabrication techniques combined with layer-by-layer processing. We show that the concepts of radiofrequency antenna arrays can be applied to the optical regime proving superior directional properties compared with a single planar optical antenna, particularly for emission and reception into the third dimension. Measuring the optical properties of the structure reveals that impinging light on the array is efficiently absorbed on the subwavelength scale because of the high directivity. Moreover, we show in simulations that combining the array with suitable feeding circuits gives rise to the prospect of beam steering at optical wavelengths

Atomic-scale confinement of optical fields

In the presence of matter there is no fundamental limit preventing confinement of visible light even down to atomic scales. Achieving such confinement and the corresponding intensity enhancement inevitably requires simultaneous control over atomic-scale details of material structures and over the optical modes that such structures support. By means of self-assembly we have obtained side-by-side aligned gold nanorod dimers with robust atomically-defined gaps reaching below 0.5 nm. The existence of atomically-confined light fields in these gaps is demonstrated by observing extreme Coulomb splitting of corresponding symmetric and anti-symmetric dimer eigenmodes of more than 800 meV in white-light scattering experiments. Our results open new perspectives for atomically-resolved spectroscopic imaging, deeply nonlinear optics, ultra-sensing, cavity optomechanics as well as for the realization of novel quantum-optical devices

Mode imaging and selection in strongly coupled nanoantennas

The number of eigenmodes in plasmonic nanostructures increases with complexity due to mode hybridization, raising the need for efficient mode characterization and selection. Here we experimentally demonstrate direct imaging and selective excitation of the bonding and antibonding plasmon mode in symmetric dipole nanoantennas using confocal two-photon photoluminescence mapping. Excitation of a high-quality-factor antibonding resonance manifests itself as a two-lobed pattern instead of the single spot observed for the broad bonding resonance, in accordance with numerical simulations. The two-lobed pattern is observed due to the fact that excitation of the antibonding mode is forbidden for symmetric excitation at the feedgap, while concomitantly the mode energy splitting is large enough to suppress excitation of the bonding mode. The controlled excitation of modes in strongly coupled plasmonic nanostructures is mandatory for efficient sensors, in coherent control as well as for implementing well-defined functionalities in complex plasmonic devices.Comment: 11 pages, 5 figures, 1 supplementary informatio

Prospect of vasoactive intestinal peptide therapy for COPD/PAH and asthma: a review

There is mounting evidence that pulmonary arterial hypertension (PAH), asthma and chronic obstructive pulmonary disease (COPD) share important pathological features, including inflammation, smooth muscle contraction and remodeling. No existing drug provides the combined potential advantages of reducing vascular- and bronchial-constriction, and anti-inflammation. Vasoactive intestinal peptide (VIP) is widely expressed throughout the cardiopulmonary system and exerts a variety of biological actions, including potent vascular and airway dilatory actions, potent anti-inflammatory actions, improving blood circulation to the heart and lung, and modulation of airway secretions. VIP has emerged as a promising drug candidate for the treatment of cardiopulmonary disorders such as PAH, asthma, and COPD. Clinical application of VIP has been limited in the past for a number of reasons, including its short plasma half-life and difficulty in administration routes. The development of long-acting VIP analogues, in combination with appropriate drug delivery systems, may provide clinically useful agents for the treatment of PAH, asthma, and COPD. This article reviews the physiological significance of VIP in cardiopulmonary system and the therapeutic potential of VIP-based agents in the treatment of pulmonary diseases

Kompressibilität und Strukturumwandlungen im flüssigen Äthylen

The isothermal compressibility of liquid ethylene was measured at 142.8 °K with a high resolution compressibility cell. The compressibility vs. pressure curve shows three ma-xima between 5 and 45 atmospheres and a marked decrease above 45 atmospheres. A tentative explanation of the pheno-menon is given in terms of structure changes

Selbstdiffusion im flüssigen Ammoniak

In der vorliegenden Untersuchung wurde die Selbstdiffusion im flüssigen Ammoniak durch gleichzeitige Isotopenmarkierung mit Deuterium und Stickstoff-15 $(N^{14}H_{2}D und N^{15}H_{3})$ gemessen. Hierzu wurde die Kapillarenmethode verwendet. Die Diffusionsmeßzelle bestand im wesentlicqen aus einer mitindiziertem Ammoniak gefüllten Kapillare,·die beiderseits durch Ventile verschlossen werden konnte. Die Kapillare befand sich in einem größeren gut durchmischten Volumen von Ammoniak natürlicher Isotopenzusammensetzung. Aus den massenspektrometrisch bestimmten Isotopenkonzentrationen des Ammoniaks innerhalb undaußerhalb der Kapillare,vor und nach Beendigung eines Versuchs, wurden Diffusionskoeffizienten unter Verwendung der entsprechenden Lösung des zweiten Fickschen Gesetzes ermittelt. Mit Hilfe eines Umlaufkältethermostaten konnten Meßtemperaturen im Bereich von -60 bis +20° C mit einer Schwankung von ±0,05° Ckonstant gehalten werden. Zur Isotopenarialyse wurden die Ammoniakproben an einem heißen Wolframdraht unter laufender Abtrennung des Wasserstoffs vollständig zersetzt. Es ergaben sich für die Temperaturabhängigkeit zwischen -60 und +18° C bei dem jeweiligen Sättigungsdruck des Ammoniaks von etwa 20 Torr bis 8 at folgende Arrhenius Ausdrücke: $D_{DEUT} = 3,8 \cdot 10^{-3} exp - (\frac{2000 \pm 30}{RT})$ / $D_{ST-15} = 3,6 \cdot 10^{-3} exp - (\frac{1970 \pm 40}{RT})$ Der maximale Fehler der einzelnen Meßwerte der Diffusionskoeffizienten wurde auf $\pm$ 2,5 % abgeschätzt. Während der Ausführung der vorliegenden Untersuchung veröffentlichte Spin Echo Messungen in einem Temperaturbereich von -70 bis -34° C werden durch folgende Beziehung beschrieben: $D_{Sp.E} = 4,0 \cdot 10^{-3} exp - (\frac{2020 \pm 50}{RT})$ [...