Selective laser sintering of porcelain Danezan, A.; Delaizir, G.; Tessier-Doyen, N. ...
Journal of the European Ceramic Society,
02/2018, Letnik:
38, Številka:
2
Journal Article
Recenzirano
Selective Laser Sintering (SLS) technique is used to fabricate 3D porcelain products with complex shapes. Commercial powder has been studied and optimized in terms of morphology and particle size ...distribution in order to get a perfect powder layerwise which remains the critical step of such a technique. The influence of laser energy density (through the laser power and scan speed) and hatching space have been investigated to determine the optimized parameters that allow the greater densification of this complex multi-materials composed of kaolinite, quartz and potassium feldspar. The laser-sintered porcelain products which exhibit about 60% of porosity have been post-treated at 1350°C under vacuum or air to further improve densification.
African tropical forests are generally considered less diverse than their Neotropical and Asian counterparts. By contrast, the Detarioideae is much more diverse in Africa than in South America and ...Asia. To better understand the evolution of this contrasting diversity pattern, we investigated the biogeographical and ecological origin of this subfamily, testing whether they originated in dry biomes surrounding the Tethys Seaway as currently hypothesized for many groups of Leguminosae.
We constructed the largest time-calibrated phylogeny for the subfamily to date, reconstructed ancestral states for geography and biome/habitat, estimated diversification and extinction rates, and evaluated biome/habitat and geographic shifts in Detarioideae.
The ancestral habitat of Detarioideae is postulated to be a primary forest (terra firme) originated in Africa–South America, in the early Palaeocene, after which several biome/habitat and geographic shifts occurred.
The origin of Detarioideae is older than previous estimates, which postulated a dry (succulent) biome origin according to the Tethys Seaway hypothesis, and instead we reveal a post Gondwana and terra firme origin for this early branching clade of legumes. Detarioideae include some of the most dominant trees in evergreen forests and have likely played a pivotal role in shaping continental African forest diversity.
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•We present the most comprehensive phylogeny of Rosa sections Chinenses and Synstylae.•Phylogenies based on chloroplast and nuclear markers exhibit obvious ...incongruences.•Hybridization played an important role in the evolutionary history of Rosa.
Rosa sections Chinenses and Synstylae contain approximately 39 wild species mainly distributed in East Asia and are closely related according to previous studies. But the specific relationships within these two sections were still obscure due to limited sampling, low genetic variation of molecular markers, and complex evolutionary histories. In this study, we used four chloroplast (ndhC-trnV, ndhF-rpl32, ndhJ-trnF and psbJ-petA) and two nuclear (ribosomal ITS and GAPDH) markers with an extensive geographic and taxonomic sampling to explore their evolutionary history. Our phylogenetic analyses suggested that Rosa sections Chinenses and Synstylae defined in traditional taxonomic system are not monophyletic and close to sections Caninae and Gallicanae. Additionally, our results showed incongruence between chloroplast and nuclear markers, and the patterns of incongruence might be due to ancient hybridization (genetic introgression). One putative hybrid species and three samples identified as interspecific hybrids are further discussed in terms of topological incongruence, biological characters and distribution patterns.
The genus Rosa (150-200 species) is widely distributed throughout temperate and sub-tropical habitats from the northern hemisphere to tropical Asia, with only one tropical African species. In order ...to better understand the evolution of roses, this study examines infrageneric relationships with respect to conventional taxonomy, considers the extent of allopolyploidization and infers macroevolutionary processes that have led to the current distribution of the genus.
Phylogenetic relationships among 101 species of the genus Rosa were reconstructed using sequences from the plastid psbA-trnH spacer, trnL intron, trnL-F spacer, trnS-G spacer and trnG intron, as well as from nuclear glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which was used to identify putative allopolyploids and infer their possible origins. Chloroplast phylogeny was used to estimate divergence times and reconstruct ancestral areas.
Most subgenera and sections defined by traditional taxonomy are not monophyletic. However, several clades are partly consistent with currently recognized sections. Allopolyploidy seems to have played an important role in stabilizing intersectional hybrids. Biogeographic analyses suggest that Asia played a central role as a genetic reservoir in the evolution of the genus Rosa.
The ancestral area reconstruction suggests that despite an early presence on the American continent, most extant American species are the results of a later re-colonization from Asia, probably through the Bering Land Bridge. The results suggest more recent exchanges between Asia and western North America than with eastern North America. The current distribution of roses from the Synstylae lineage in Europe is probably the result of a migration from Asia approx. 30 million years ago, after the closure of the Turgai strait. Directions for a new sectional classification of the genus Rosa are proposed, and the analyses provide an evolutionary framework for future studies on this notoriously difficult genus.
PREMISE OF THE STUDY:
Functional trait plasticity in resource capture traits has been suggested as an underlying mechanism promoting invasive species establishment and spread. Earlier studies on this ...mechanism treat invasiveness as a discrete characteristic (i.e., invasive vs. noninvasive) and do not consider the potential impacts of evolutionary history. In the present study, we used a continuous measure of invasiveness and a phylogenetic framework to quantify the relationship between functional trait expression, plasticity, and invasiveness in Rosa.
METHODS:
In a manipulative greenhouse experiment, we evaluated how light availability affects functional traits and their plasticity in Rosa sp. and the out‐group species, Potentilla recta, which vary in their invasiveness.
KEY RESULTS:
Across functional traits, we found no significant relationship between plasticity and invasiveness. However, more invasive roses demonstrated an ability to produce a more branched plant architecture, promoting optimal light capture. Invasiveness also was linked with lower photosynthetic and stomatal conductance rates, leading to increased water‐use efficiency (WUE) in more invasive roses.
CONCLUSIONS:
Our results suggest that functional trait values, rather than plasticity, promote invasive rose success, counter to earlier predictions about the role of plasticity in invasiveness. Furthermore, our study indicates that invasive roses demonstrate key functional traits, such as increased WUE, to promote their success in the high‐light, edge habitats they commonly invade.
The taxonomy of the genus Rosa is complex, not least because of hybridisations between species.We aimed to develop a method to connect the diploid Rosa taxa to the allopolyploid taxa to which they ...contributed, based on the sharing of haplotypes. For this we used an SNPSTR marker, which combines a short tandem repeat (STR; microsatellite) marker with single nucleotide polymorphisms (SNPs) in the flanking sequences. In total, 53 different sequences (haplotypes) were obtained for the SNPSTR marker, Rc06, from 20 diploid and 35 polyploid accessions from various species of Rosa. Most accessions of the diploid species had only one allele, while accessions of the polyploid species each contained two-to-five different alleles. Twelve SNPs were detected in the flanking sequences, which alone formed a total of 18 different haplotypes. A maximum likelihood dendrogram revealed five groups of haplotypes. Diploid species in the same Section of the genus Rosa contained SNP haplotypes from only one haplotype group. In contrast, polyploid species contained haplotypes from different haplotype groups. Identical SNP haplotypes were shared between polyploid species and diploid species from more than one Section of the genus Rosa. There were three different polymorphic repeat regions in the STR region. The STR repeat contained eight additional SNPs, but these contributed little to the resolution of the haplotype groups. Our results support hypotheses on diploid Rosa species that contributed to polyploid taxa. Finding different sets of haplotypes in different groups of species within the Sections Synstylae and Pimpinellifoliae supports the hypothesis that these may be paraphyletic.
Ground granulated blast furnace slags (GGBS) are glassy by-products from iron production that are commonly used as supplementary cementitious materials in blended cements. The glass structure of ...seven industrial GGBS was investigated by Raman and nuclear magnetic resonance spectroscopies. The complex composition of the slags induced multiple analytical challenges. Under usual continuous excitation, the Raman signal was masked by strong luminescence, so that analysis was carried out on a time-resolved Raman (TRR) device. TRR allowed to eliminate luminescence and resulted in exploitable spectra that showed variations in line with theoretical NBO/T values. The analysis of
27
Al and
29
Si NMR spectra was complicated by the presence of paramagnetic nuclei and the wide variety of environments. Nevertheless,
27
Al NMR showed that Al was present as a network former, mainly in fourfold coordination and careful analyses of
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Si NMR spectra allowed the comparison of glass network polymerization of industrial GGBS in line with the theoretical NBO/T based on their composition.
Premise of research. We examine floral evolution and phylogenetic relationships in the monophyletic Detarieae and related lineages of Caesalpinioideae. Tribe Detarieae (82 genera) includes nearly ...half of the genera in subfamily Caesalpinioideae and represents some of the most diverse legumes with respect to floral morphology.
Methodology. A total of 67 floral ontogenetic and morphological characters were combined with DNA sequences from the plastidtrnL-FandmatKregions of 34 Detarieae species and representatives of Cassieae, Cercideae, Caesalpinieae, Papilionoideae, and Mimosoideae, for which we have near-complete ontogenetic series. The morphological and ontogenetic characters were optimized onto the resulting most parsimonious phylogenetic trees and Bayesian topology to study character evolution.
Pivotal results. Our study supports previously proposed relationships within the tribe Detarieae and among caesalpinioid lineages and indicates that certain features (bracteole and hypanthium characters, sepal initiation, anther position in bud, overlap in timing of initiation of organ whorls) are phylogenetically informative for particular clades whereas others (reductions in petal and stamen number, sepal and petal initiation patterns) have evolved multiple times in parallel in the Detarieae and other Caesalpinioideae. These analyses suggest that modifications that occur early in ontogeny can be good phylogenetic characters for distinguishing both major taxonomic groups and more closely related taxa and that morphological differences that differentiate species within genera can be caused by changes that occur at all stages of ontogeny. Phylogenetic distribution of character states and ontogenetic evidence suggest that in the Caesalpinioideae, loss or suppression of organs within a whorl, both of which are very common, usually does not affect development in subsequent whorls.
Conclusions. Our analyses reveal several switches from zygomorphy to actinomorphy (and vice versa), but in Caesalpinioideae (contrary to Papilionoideae), zygomorphy is likely not clearly associated with higher diversification rates. This study suggests that floral initiation patterns are much more variable in Caesalpinioideae than in the other two subfamilies. Although particular patterns may be canalized in certain lineages of the subfamily (Cercideae, Caesalpinieae), in other clades (Detarieae, Dialiinae) floral development is more labile, explaining the high diversity in floral morphology encountered overall in the paraphyletic Caesalpinioideae.
BACKGROUND AND AIMS: Previous molecular phylogenetic studies disagree with the informal generic-level taxonomic groups based on morphology. In this study morphological characters in the caesalpinioid ...clade Detarieae are evaluated within a phylogenetic framework as a means of better understanding phylogenetic relationships and morphological evolution. METHODS: Morphological characters were observed and scored for representative species of Detarieae focusing on the resin-producing genera. Phylogenetic analyses were carried out with morphological characters alone and then combined with DNA sequences. KEY RESULTS: Despite a high level of homoplasy, morphological data support several clades corresponding to those recovered in molecular phylogenetic analyses. The more strongly supported clades are each defined by at least one morphological synapomorphy. Several characters (e.g. apetaly) previously used to define informal generic groups evolved several times independently, leading to the differences observed with the molecular phylogenetic analyses. Although floral evolution is complex in Detarieae some patterns are recovered. CONCLUSIONS: New informal taxonomic groupings are proposed based on the present findings. Floral evolution in the diverse Detarieae clade is characterized by a repeated tendency toward zygomorphy through the reduction of lateral petals and toward complete loss of petals.
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