Genetic variation in hawthorn (Crataegus spp.) using RAPD markers

In this study, we report the use of random amplified polymorphic DNA (RAPD) to determine genetic relationships in the genus Crataegus. Five species, including Crataegus monogyna, Crataegus meyeri, Crataegus aronia, Crataegus pentagyna and Crataegus pontica were chosen from northwest forests of Iran and analyzed. Nine RAPD primers reproducibly and strongly generated 101 discrete markers. Seventy six (76) of these were polymorphic (75.25%), with an average of 11.2 markers per primer. Jaccard’s distance coefficient based on RAPD markers indicated that the relative genetic distance between species is high, ranging from a minimum of 0.575 between C. monogyna and C. meyeri to a maximum of 0.728 between C. aronia and C. monogyna. Dendrogram was constructed based on unweighted pair group method analysis (UPGMA) from RAPD data. The range in similarity coefficient indicated high genetic distance among the species of this genus. However, low variation (0.575 to 0.728) in genetic distance for Crataegus in northwest forests of Iran is also evident.Key words: Crataegus, RAPD, genetic variation, Jaccard’s coefficient

Spiral Growth and Step Edge Barriers

The growth of spiral mounds containing a screw dislocation is compared to the growth of wedding cakes by two-dimensional nucleation. Using phase field simulations and homoepitaxial growth experiments on the Pt(111) surface we show that both structures attain the same characteristic large scale shape when a significant step edge barrier suppresses interlayer transport. The higher vertical growth rate observed for the spiral mounds on Pt(111) reflects the different incorporation mechanisms for atoms in the top region and can be formally represented by an enhanced apparent step edge barrier.Comment: 11 pages, 4 figures, partly in colo

Осаждение покрытий из хрома и никеля с помощью магнетронного диода с «горячей» мишенью

В настоящей работе представлены результаты исследования свойств покрытий из хрома и никеля от режимов распыления "горячей" металлической мишени в плазме магнетронной распылительной системы.This work reports on the dependence of properties of Cr and Ni coatings on operation parameters of magnetron sputtering system with hot target

Structure and morphology of perylene films grown on different substrates

In this study the structural and morphological properties of perylene films deposited on different substrates have been investigated. The film properties have been studied by employing a range of techniques including atomic force microscopy, x-ray diffraction, and drop shape analysis for the determination of the surface free energy. For films deposited on top of Al2O3, the perylene molecules have a fiber texture ordering perpendicular to the substrate, while for films deposited on top of a Au(111) layer, only for thicker films above 400 nm were diffraction peaks observed. The different growths of perylene on top of these substrates are attributed to the different strengths of the molecule-substrate interaction. (C) 2008 American Institute of Physics