Bending and springback prediction method based on multi-scale finite element analyses for high bendability and low springback sheet generation

In this study, a sheet bendability and springback property evaluation technology through bending test simulations is newly developed using our multi-scale finite element analysis code, which is based on the crystallographic homogenization method

Crystal texture evolution analyses in metal drawing processes by using two-scale finite element method

Recently, the crystallographic control technology in the aluminum wire drawing process has been a key technology in the aluminum industries, which produces high-strength wires for the electric, automotive and aircraft parts. This newly proposed “process metallurgy” computational technology in the industrial forming process consists of the two-scale finite element (FE) analyses and the optimum design algorithm.We developed two-scale FE analyses code based on the crystallographic homogenization method by considering the hierarchical structure of polycrystal aluminium alloy metal. It can be characterized as the combination of two-scale structure, such as the microscopic polycrystal structure and the macroscopic elastic plastic continuum. Micro polycrystal structure is modelled as a three dimensional representative volume element (RVE). RVE is featured as 3x3x3 eight-nodes solid finite elements, which has totally 216 crystal orientations. This FE analyses code can predict the deformation, strain and stress evolutions in the wire drawing processes in the macro-scale, and simultaneously the crystal texture and hardening evolutions in the micro-scale. In this study, we analyzed the texture evolution in the “three passes” wire drawing processes by using our two-scale FE analyses code under conditions of various drawing angles of die. We evaluated the texture evolution in the surface and center regions of the wire cross section, and to clarify the effects of processing conditions on the texture evolution

Perfil de virulência de dez isolados de Paracoccidioides brasiliensis: associação com morfologia e padrão genético

Ten isolates of Paracoccidioides brasiliensis were examined for differences in virulence in outbred mice intravenously inoculated with the fungus, associated with mycelial morphology, and genetic patterns measured by random amplified polymorphic DNA (RAPD). Virulence was evaluated by viable yeast cell recovery from lungs and demonstration of histopathologic lesions in different organs. The results showed that the isolates presented four virulence degrees: high virulence, intermediate, low and non-virulence. RAPD clustered the isolates studied in two main groups with 56% of genetic similarity. Strains with low virulence, Pb265 or the non-virulent, Pb192, showed glabrous/cerebriform morphology and high genetic similarity (98.7%) when compared to the other isolates studied. The same was observed with Bt79 and Bt83 that shared 96% genetic similarity, cottony colonies and high virulence. The RAPD technique could only discriminate P. brasiliensis isolates according to glabrous/cerebriform or cottony colonies, and also high from low virulence strains. Isolates with intermediate virulence such as Pb18, Pb18B6, Bt32 and Bt56 showed variability in their similarity coefficient suggesting that RAPD was able to detect genetic variability in this fungal specie. Virulence profile of P. brasiliensis demonstrated that both mycelial morphologic extreme phenotypes may be associated with fungal virulence and their in vitro subculture time. Thus, RAPD technique analysis employed in association with virulence, morphologic and immunologic aspects might prove adequate to detect differences between P. brasiliensis isolates.Dez isolados de P. brasiliensis foram avaliados em relação à patogenicidade por inoculação intravenosa em camundongos e associação com morfologia miceliana e padrão genético por amplificação genônica do DNA polimórfico (RAPD). A patogenicidade, avaliada por recuperação de fungos viáveis a partir de tecido pulmonar e por lesões histopatológicas em diferentes órgãos, mostrou que os isolados apresentaram quatro graus de virulência: alta virulência, virulência intermediária, baixa virulência e não virulência. A técnica de RAPD agrupou os isolados em dois grupos com 56% de similaridade genética. Amostras com baixa virulência Pb265 ou não virulência Pb192 apresentaram morfologia glabra/cerebriforme e alta similaridade genética (98,7%) quando comparadas com os outros isolados estudados. O mesmo foi observado com os isolados Bt79 e Bt83, que compartilharam 96% de semelhança genética, colônias cotonosas e alta virulência. Essa técnica pode discriminar apenas isolados com morfologia glabra da cotonosa e com alta e baixa virulência. Isolados com virulência intermediária como Pb18, Pb18B6, Bt32 e Bt54 mostraram variabilidade no coeficiente de similaridade, sugerindo que a técnica de RAPD permite mostrar variabilidade genética nessa espécie fúngica. O estudo do perfil de virulência das amostras de P. brasiliensis demonstrou que os dois fenótipos extremos de morfologia miceliana podem ser associados com a virulência do fungo e com o tempo de subcultivo in vitro. Assim, a análise de RAPD, utilizada em conjunto com aspectos de virulência, morfológicos e imunológicos pode ser considerada adequada para detectar diferenças entre isolados de P. brasiliensis

The Tree versus the Forest: The Fungal Tree of Life and the Topological Diversity within the Yeast Phylome

A recurrent topic in phylogenomics is the combination of various sequence alignments to reconstruct a tree that describes the evolutionary relationships within a group of species. However, such approach has been criticized for not being able to properly represent the topological diversity found among gene trees. To evaluate the representativeness of species trees based on concatenated alignments, we reconstruct several fungal species trees and compare them with the complete collection of phylogenies of genes encoded in the Saccharomyces cerevisiae genome. We found that, despite high levels of among-gene topological variation, the species trees do represent widely supported phylogenetic relationships. Most topological discrepancies between gene and species trees are concentrated in certain conflicting nodes. We propose to map such information on the species tree so that it accounts for the levels of congruence across the genome. We identified the lack of sufficient accuracy of current alignment and phylogenetic methods as an important source for the topological diversity encountered among gene trees. Finally, we discuss the implications of the high levels of topological variation for phylogeny-based orthology prediction strategies

Distribution of Introns in Fungal Histone Genes

Saccharomycotina and Taphrinomycotina lack intron in their histone genes, except for an intron in one of histone H4 genes of Yarrowia lipolytica. On the other hand, Basidiomycota and Perizomycotina have introns in their histone genes. We compared the distributions of 81, 47, 79, and 98 introns in the fungal histone H2A, H2B, H3, and H4 genes, respectively. Based on the multiple alignments of the amino acid sequences of histones, we identified 19, 13, 31, and 22 intron insertion sites in the histone H2A, H2B, H3, and H4 genes, respectively. Surprisingly only one hot spot of introns in the histone H2A gene is shared between Basidiomycota and Perizomycotina, suggesting that most of introns of Basidiomycota and Perizomycotina were acquired independently. Our findings suggest that the common ancestor of Ascomycota and Basidiomycota maybe had a few introns in the histone genes. In the course of fungal evolution, Saccharomycotina and Taphrinomycotina lost the histone introns; Basidiomycota and Perizomycotina acquired other introns independently. In addition, most of the introns have sequence similarity among introns of phylogenetically close species, strongly suggesting that horizontal intron transfer events between phylogenetically distant species have not occurred recently in the fungal histone genes

Addressing Inter-Gene Heterogeneity in Maximum Likelihood Phylogenomic Analysis: Yeasts Revisited

Phylogenomic approaches to the resolution of inter-species relationships have become well established in recent years. Often these involve concatenation of many orthologous genes found in the respective genomes followed by analysis using standard phylogenetic models. Genome-scale data promise increased resolution by minimising sampling error, yet are associated with well-known but often inappropriately addressed caveats arising through data heterogeneity and model violation. These can lead to the reconstruction of highly-supported but incorrect topologies. With the aim of obtaining a species tree for 18 species within the ascomycetous yeasts, we have investigated the use of appropriate evolutionary models to address inter-gene heterogeneities and the scalability and validity of supermatrix analysis as the phylogenetic problem becomes more difficult and the number of genes analysed approaches truly phylogenomic dimensions. We have extended a widely-known early phylogenomic study of yeasts by adding additional species to increase diversity and augmenting the number of genes under analysis. We have investigated sophisticated maximum likelihood analyses, considering not only a concatenated version of the data but also partitioned models where each gene constitutes a partition and parameters are free to vary between the different partitions (thereby accounting for variation in the evolutionary processes at different loci). We find considerable increases in likelihood using these complex models, arguing for the need for appropriate models when analyzing phylogenomic data. Using these methods, we were able to reconstruct a well-supported tree for 18 ascomycetous yeasts spanning about 250 million years of evolution

The Major Roles of DNA Polymerases Epsilon and Delta at the Eukaryotic Replication Fork Are Evolutionarily Conserved

Coordinated replication of eukaryotic genomes is intrinsically asymmetric, with continuous leading strand synthesis preceding discontinuous lagging strand synthesis. Here we provide two types of evidence indicating that, in fission yeast, these two biosynthetic tasks are performed by two different replicases. First, in Schizosaccharomyces pombe strains encoding a polδ-L591M mutator allele, base substitutions in reporter genes placed in opposite orientations relative to a well-characterized replication origin are strand-specific and distributed in patterns implying that Polδ is primarily involved in lagging strand replication. Second, in strains encoding a polε-M630F allele and lacking the ability to repair rNMPs in DNA due to a defect in RNase H2, rNMPs are selectively observed in nascent leading strand DNA. The latter observation demonstrates that abundant rNMP incorporation during replication can be tolerated and that they are normally removed in an RNase H2-dependent manner. This provides strong physical evidence that Polε is the primary leading strand replicase. Collectively, these data and earlier results in budding yeast indicate that the major roles of Polδ and Polε at the eukaryotic replication fork are evolutionarily conserved