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1.
The phylogeny of the fungus gnat family Mycetophilidae (Diptera) is reconstructed with a focus on the species‐rich and taxonomically difficult subfamilies Gnoristinae and Mycomyinae. The multigene phylogenetic analyses are based on five nuclear (18S, 28S, CAD, MCS, ITS2) and four mitochondrial (12S, 16S, COI, CytB) gene markers. The analyses strongly support the monophyly of Mycetophilidae and the subfamilies Manotinae, Sciophilinae, Leiinae, and Mycomyinae, although Gnoristinae is paraphyletic with respect to Mycetophilinae. All the genera and groups of genera included are supported as monophyletic, except for Acomoptera Vockeroth, Boletina Staeger, Dziedzickia Johannsen, Ectrepesthoneura Enderlein, and Neoempheria Osten Sacken. Ancestral character state reconstructions were applied to two morphological features present in Gnoristinae and Mycomyinae (i.e. presence of setae on wing membrane and wing vein R4) in order to assess their evolution. The wing vein R4 appears as an unstable character, spread throughout different clades. A dated phylogeny of the family Mycetophilidae showed that most of the subfamilies of Mycetophilidae originated and diversified during the Cretaceous. The youngest subfamilies, originated in the Paleogene, appear to be Mycomyinae and Mycetophilinae.  相似文献   
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This paper is concerned with gene survival in a population which may increase without density dependence according to a generalization of the Moran model for haploid individuals. A selective advantage to one allele and the possibility of differential reproductive rates are allowed. Simple conditions are given for ultimate homozygosity to be certain and for the possibility of ultimate polymorphism. The results complement and extend those of Heyde (1981, 1982).  相似文献   
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The function and viability of cultured, transplanted, or encapsulated pancreatic islets is often limited by hypoxia because these islets have lost their vasculature during the isolation process and have to rely on gradient-driven passive diffusion, which cannot provide adequate oxygen transport. Pancreatic islets (islets of Langerhans) are particularly susceptible due to their relatively large size, large metabolic demand, and increased sensitivity to hypoxia. Here, finite element method (FEM) based multiphysics models are explored to describe oxygen transport and cell viability in avascular islets both in static and in moving culture media.  相似文献   
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Aromatic amines are important intermediates in industrial manufacturing. They are used in a large number of products, such as pesticides, dyes, plastics and pharmaceuticals. The parent arylamines can be metabolically released from these arylamine-based compounds and form DNA and protein adducts after N-oxidation to N-hydroxy arylamines. Aromatic amine derivatives, including the industrial intermediates acetoacetanilide, acetoacet-m-xylidide and N-ethylaniline, were examined for their ability to form Hb adducts in rats as potential biomarkers of exposure. The haemoglobin binding indices (HBI=binding [mmol mol-1 Hb]/dose [mmol kg-1 body weight]) of the arylamines were determined 24 h after oral administration to female Wistar rats. The precipitated haemoglobin was dissolved in 0.1 M sodium hydroxide in the presence of internal standards. After hexane extraction the released arylamines were analysed by gas chromatography-mass spectrometry (GC-MS). For aniline released from acetoacetanilide an HBI of 15 and for 2,4-dimethylaniline released from acetoacet-m-xylidide an HBI of 0.129 were determined. The HBIof aniline released from N-ethylaniline was 45.  相似文献   
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