Guided growth of millimeter-long horizontal nanowires with controlled orientations

The large-scale assembly of nanowires with controlled orientation on surfaces remains one challenge preventing their integration into practical devices. We report the vapor-liquid-solid growth of aligned, millimeter-long, horizontal GaN nanowires with controlled crystallographic orientations on different planes of sapphire. The growth directions, crystallographic orientation, and faceting of the nanowires vary with each surface orientation, as determined by their epitaxial relationship with the substrate, as well as by a graphoepitaxial effect that guides their growth along surface steps and grooves. Despite their interaction with the surface, these horizontally grown nanowires display few structural defects, exhibiting optical and electronic properties comparable to those of vertically grown nanowires. This paves the way to highly controlled nanowire structures with potential applications not available by other means.     

Neue Baumschulwerfzeuge

Ohne Zusammenfassung     

Apparent Seroprevalence of Salmonella spp. in Harp Seals in the Greenland Sea as Determined by Enzyme-linked Immunosorbent Assay

An indirect ELISA was developed as a possible tool for surveillance of the seroprevalence of Salmonella spp. in harp seals. This species is hunted for human consumption and thus transmission of disease to humans cannot be excluded. To cover a broad spectrum of serogroups, a mixture of the lipopolysaccharides (LPS) of S. typhimurium and S. choleraesuis was used as the antigen in this pilot study. Chicken anti-harp-seal immunoglobulin horseradish peroxidase conjugate served as the immunoconjugate. Sera from four captive harp seals, which were Salmonella culture-negative and had no clinical or historical evidence of salmonellosis, were used as negative controls. After immunization with an inactivated S. typhimurium vaccine, further sera from these seals were used as positive controls, as no serum from naturally infected animals was available. Serum samples from 93 harp seals caught in the Greenland sea in 1999 were examined, and anti-Salmonella antibodies were found in the samples from two individuals (seroprevalence 2.2%). Although Salmonella has been isolated from other pinniped species, this is the first documentation of Salmonella-seropositive harp seals. This study contributes to the evaluation of the importance of salmonellosis in arctic marine mammals and thus to the prevention of potential outbreaks of this important zoonosis.     

Phytomyza rufipes Mg. (Dipt.) als Blumenkohlschädling

Ohne Zusammenfassung Mit 2 Abbildungen.     

Apple tree phytomass in plantings with different crown shapes

It is established that the studied crown shapes of apple trees grafted on M9 rootstock are small-sized. The total biomass of one tree is 34.3–45.0 kg, the economic phytomass (fruits) is 13.4–20.0 kg, and its variation depends to a greater degree on the biology of the variety and then on the crown shape.     

Lebensweise und Systematik der „Schwarzen Blattläuse”

Ohne Zusammenfassung     

Eine neue Methode zur vergleichenden Beurteilung von der Wirksamkeit von Insektenfraßgiften

Ohne Zusammenfassung