ALBERT

Notizen: Josephson arrays containing 2000 and 20 160 Nb/Al2O3/Nb tunnel junctions produce stable quantized voltage steps up to 1.5 and 14.5 V, respectively, with current amplitudes on the order of 100 μA. In precision measurements these voltage steps proved to be stable for typically 30 min. Fabricating the voltage standards with the help of the Nb/Al2O3/Nb technology results in a long durability.

Notizen: The inhibition and perturbations of surface photochemistry, due to the coupling of the excited state to the surface, are discussed as it pertains to CH3 Br adsorbed on nickel. Photofragmentation of CH3 Br was observed on a brominated Ni(111) surface, with the fragmentation process being strongly perturbed at low coverages. The perturbations are attributed to charge transfer processes. Direct photofragmentation was observed as well as a surface specific dissociative electron attachment channel. Cross section values are reported for fragmentation at 193 and 248 nm.

Notizen: A new and improved version of the technique of H atom photofragment translational spectroscopy has been applied to a study of H2S photodissociation at 121.6 nm. The primary fragmentation pathways leading to H+SH(A) fragments and H+H+S(1D) atoms are observed to dominate the product yield; the yield of H atoms formed in conjunction with ground state SH(X) fragments is undetectably small. The majority of the SH(A) fragments are formed in their v=0 level with a rotational state population distribution that spans all possible bound and quasibound rotational levels. The experimental determination of the energies of these hitherto unobserved high rotational states has enabled a refinement of the SH(A) potential energy function, an improved estimate of the SH(A) well depth (9280±600 cm−1), and thus of the SH(X) ground state bond dissociation energy D00 (S–H)=3.71±0.07 eV. All aspects of the observed energy disposal in the title photodissociation process may be understood, qualitatively, if it is assumed that (i) the primary fragmentations occur on the B˜ 1A1 potential energy surface and (ii) Flouquet's ab initio calculations of portions of this surface [Chem. Phys. 13, 257 (1976)] correctly predict its gross topological features.

Notizen: A commercially available flat flame burner with a sintered porous bronze disk was used to stabilize premixed H2/air flames at atmospheric pressure. Temperatures for various stoichiometries, flow rates, and heights above the burner disk have been measured by coherent anti-Stokes Raman scattering with an accuracy of ≈2.5%. The corresponding exhaust gas compositions have been derived from equilibrium calculations. This burner together with the data presented in this article can be used for the verification or calibration of a variety of measuring techniques in combustion research.

Notizen: Malachite green, the drug most commonly used against ichthyophthiriosis, is suspected to be carcinogenic and mutagenic. Therefore, the use of this de is restricted or rohibited in several countries. In order to find an alternative, the in vitro effect of the following substances on different stages of Ichthyophthirius multifilis (tomont, cyst and tomite) was investigated: Amphotericin B, chloram-phenicol, chlortetracycline, dimetridazole, formalin, furazolidone, oxytetracycline and sulfachlorpy-razine, and as controls malachite green and mixtures of malachite green and formalin. In vitro, Amphothericin B, chlortetracycline, formalin and mixtures of malachite green and formalin showed the same potential as malachite green. Furazolidone inhibited the development of theronts but was relatively ineffective against emerged theronts. Little or no parasiticidal effect could be attributed to chloramphenicol, dimetridazole, oxytetracline or sulfachlorpyrazine. The substances, which had proved all highly effective in vitro, were subsequently examined in vivo in a bath treatment and/or using medicated diets. Thereby successful treatment was achieved only with malachite green and mixtures of malachite green and formalin. All other substances were either ineffective or their use resulted in increased mortality (formalin).

Notizen: The influence of light and/or fish on the behaviour of the infective stage of Ichthyophthirius multifiliis was investigated in an aquarium (30 × 10 × 7,5 cm) divided by a net into two equal compartments in the following experiments: 1. illuminated versus darkened compartment, 2. compartment with fish versus compartment without fish and 3. combinations of 1. and 2. After 45 to 70 minutes, significantly more theronts were found in the illuminated compartment than in the darkened one. When adding a fish to one of the two illuminated compartments, the number of theronts was significantly lower in the compartment containing the fish. The combination of tight and fish factors revealed significantly more theronts in the illuminated area with no fish than in the darkened area containing one fish. However, no difference occurred between the number of theronts in an illuminated area with fish and a darkened one without fish. These findings allow the suggestion that theronts show a positive phototaxis but no active search for fish.〈section xml:id="abs1-2"〉〈title type="main"〉Résumé Influence de la, lumière et/ou d'un poisson sur ie comportement des tomites d'Ichthyophthirius multifiliisL'influence de la lurmière et/ou la présence ainsi que l'absence d'un poisson sur le comportement du stade infectieux du cilié parasite Ichthyophthirius multifiliis (tomites) rurent étudiées dans un aquarium (30 × 10 × 7,5cm) divisé par un filet en deux compartiments dans les conditions suivantes: I. l'un illumine, 1'autre pas, 2. l'un contenant un poisson, l'autre pas et 3. une combinaison des points précédents. Après un laps de temps de 45 sà 70 minutes le nombre de parasites dans le compartiment illuminéétait significativement supérieur sà celui du compartiment sombre. Lorsque les deux compartiments étaient éclairés d'une manière identique, celui contenant un poisson comptait moins de ciliés que l'autre, dépourvu de poisson. La combinaison des facteurs lumière et poisson démontrait de manière significative qu'il y avait plus de parasites dans la partie d'aquarium élairée sans poisson que dans celle sans éclairage avec un poisson. En revanche aucune différence nette du nombre de tomites n'a pu être constatée entre le compartiment éclairé contenant un poisson et celui sans éclairage et sans poisson. Ces résultats permettent de tirer les conclusions suivantes: les tomites montrent un comportement phototactique positif, par contre aucune recherche active de l'höte n'a pu être décelée.〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung Einflnß von Licht und/oder einem Fisch auf Schwärmer des Ziliaten Ichthyophthirius multifiliisDas Verhalten von infektiösen Stadien des parasitären Ziliaten Ichthyophthirius multifiliis in Abhängigkeit der Lichtverhältnisse und/oder der Präsenz bzw. Absenz eines Fisches wurde untersucht. Dazu wurde ein Aquarium (30 × 10 × 7,5 cm) mit einem Netz in zwei gleiche Kompartimente unterteilt und folgenden Bedingungen ausgesetzt: 1. belichtetes Abteil gegen unbelichtetes, 2. Abteil mit Fisch gegen Abteil ohne Fisch und 3. Kombinationen von 1. und 2. Nach 45 bis 70 Minuten fanden sich signinkant mehr Schwärmer im beleuchteten Teil. Die Zahl der Parasiten im Abteil mit Fisch des gleichmäßig beleuchteten Aquariums war signifikant kleiner und im Vergleich zum abgedunkelten mit Fisch waren signifikant mehr Schwärmer im beleuchteten Teil ohne Fisch. Kein klarer Unterschied bestand zwischen der Anzahl Parasiten im beleuchteten Abteil mit Fisch und derjenigen im abgedunkelten Teil ohne Fisch. Es wird daraus geschlossen, daß Schwärmer positiv phototaktiscn sind, jedoch einen Win nicht aktiv suchen.

Notizen: Abstract. Young rainbow trout were fed diets containing different combinations of ascorbyl-monophosphatc (vitamin C) and all-rac-alpha-tocopheryl acetate (vitamin E) for 31 weeks. The fish fed a diet deficient in both vitamins exhibited a high mortality and were anaemic after 8–12 weeks. Histopathological examination revealed a severe muscular dystrophy and splenic haemosiderosis. Fish fed a diet deficient in vitamin C but high in vitamin E developed the typical signs of vitamin C deficiency after 16–20 weeks, including reduced growth rate, haemorrhages and gill alterations as well as severe deformations and fractures of the vertebral column. A diet deficient in vitamin E but high in vitamin C led to splenic haemosiderosis after 20 weeks. At the end of the experiment, this group showed significantly decreased haematocrit, haemoglobin content and red blood cell numbers and increased spontaneous erythrocytc haemolysis. In a second experiment, older fish of the same origin were fed diets containing high or low levels of ascorbyl-monophosphatc and all-rac-alpha-tocopheryl acetate, respectively, for 23 weeks. The results were qualitatively the same as in the first experiment, but the onset of mortality in fish fed the diet deficient in both vitamins occurred later (weeks 18–23) and deformations of the vertebral column were absent. Haematocrit, haemoglobin content and red blood cell numbers were significantly decreased in the group fed the diet deficient in both vitamins and crythrocyte haemolysis was increased in both groups receiving a vitamin E free diet, the diet deficient in both vitamins having a more pronounced effect. The results of these two experiments indicate that there is an interrelation between vitamins C and E in rainbow trout. Possible mechanisms are discussed.

Notizen: Abstract N2 Q-branch CARS spectra have been recorded and evaluated for temperature determination in a turbulent, premixed CH4/air stagnation flame with a burner of 40 mm diameter and 22 kW thermal load. Temperature histograms on the flame axis at different distances from the stagnation plate have been measured. Problems of practical applicability are addressed, including those arising from the limited spatial resolution of the BOXCARS geometry, from an insufficient dynamic range of the diode array detector, and from a memory effect of the detector in the case of measurements in highly turbulent flame areas with strong intermittency. Some information is given on the computerized acquisition and on the evaluation of the large amounts of data that are necessary for extensive investigations in large combustion systems.