Solid solution hardening of vacancy stabilized TixW1−xB2

AbstractWe present a combined experimental and theoretical investigation of sputter deposited thin films in the ternary system Ti1−xWxB2. Solid solutions of Ti1−xWxB2−z were prepared by physical vapor deposition (PVD) and, over the whole composition range, found to crystallize in the AlB2 structure type. The obtained films exhibit good thermal stability and high hardness, evidencing a maximum value of almost 40GPa for Ti0.67W0.33B2−z. The effect of vacancies on stabilization and mechanical properties of the AlB2 structure type is discussed, using ab initio simulations. Based on our results, we can conclude that vacancies are crucial for the phase stability of PVD deposited Ti1−xWxB2−z coatings

Could hair-lichens of high-elevation forests help detect the impact of global change in the Alps?

Climate change and the anthropic emission of pollutants are likely to have an accelerated impact in high-elevation mountain areas. This phenomenon could have negative consequences on alpine habitats and for species of conservation in relative proximity to dense human populations. This premise implies that the crucial task is in the early detection of warning signals of ecological changes. In alpine landscapes, high-elevation forests provide a unique environment for taking full advantage of epiphytic lichens as sensitive indicators of climate change and air pollution. This literature reviewis intended to provide a starting point for developing practical biomonitoring tools that elucidate the potential of hair-lichens, associated with high-elevation forests, as ecological indicators of global change in the European Alps. We found support for the practical use of hair-lichens to detect the impact of climate change and nitrogen pollution in high-elevation forest habitats. The use of these organisms as ecological indicators presents an opportunity to expand monitoring activities and develop predictive tools that support decisions on how to mitigate the effects of global change in the Alps

Division of Giardia isolates from humans into two genetically distinct assemblages by electrophoretic analysis of enzyme encoded at 27 loci in comparison with Giardia muris

Giardia that infect humans are known to be heterogeneous but they are assigned currently to a single species, Giardia intestinalis (syn. G. lamblia). The genetic differences that exist within G. intestinalis have not yet been assessed quantitatively and neither have they been compared in magnitude with those that exist between G. intestinalis and species that are morphologically similar (G. duodenalis) or morphologically distinct (e.g. G. muris). In this study, 60 Australian isolates of G. intestinalis were analysed electrophoretically at 27 enzyme loci and compared with G. muris and a feline isolate of G. duodenalis. Isolates of G. intestinalis were distinct genetically from both G. muris (approximately 80% fixed allelic differences) and the feline G. duodenalis isolate (approximately 75% fixed allelic differences). The G. intestinalis isolates were extremely heterogeneous but they fell into 2 major genetic assemblages, separated by fixed allelic differences at approximately 60% of loci examined. The magnitude of the genetic differences between the G. intestinalis assemblages approached the level that distinguished the G. duodenalis isolate from the morphologically distinct G. muris. This raises important questions about the evolutionary relationships of the assemblages with Homo sapiens, the possibility of ancient or contemporary transmission from animal hosts to humans and the biogeographical origins of the two clusters.G. Mayrhofer, R. H. Andrews, P. L. Ey and N. B. Chilto

Crossover of texture and morphology in (Ti1 − xAlx)1 − yYyN alloy films and the pathway of structure evolution

In our earlier published work, we have shown that there is a composition range of the (Ti 1 − x Al x ) 1 − y Y y N alloy films (0.72 b Ti/Al b 0.88) deposited at oblique vapour beam incidence and 500 °C (corresponding to zone T) in which mixed cubic TiN (c-TiN) and wurtzite AlN (w-AlN) structures were formed together with an unusual complex texture. The texture of c-TiN phase changed from 〈001〉 to b111N at a certain thickness forming a definite crossover. Moreover the c-TiNb111N and the w-AlN〈0001〉 crystals were epitaxially related with axes tilted to the direction of the vapour beam. Based on a comprehensive transmission electron microscopy (TEM) and diffraction (XRD and selected area electron diffraction (SAED)) structure and morphology analysis, we discovered the details of this exotic structure making it possible to construct the complex pathway of structure evolution including the formation of the w-AlN phase and the change of the dominating texture of c-TiN phase with thickness in dependence of the Ti/Al ratio and the deposition parameters. This pathway could be deduced from the fundamental phenomena of structure formation and may be generalised for multi-component thin film systems. A composition structure zone model has been also proposed for the (Ti 1 − x Al x ) 1 − y Y y N thin film system in the 0 b x b 1 composition range

Crossover of texture and morphology in (Ti 1 − x Al x ) 1 − y Y y N alloy films and the pathway of structure evolution

In our earlier published work, we have shown that there is a composition range of the (Ti 1 − x Al x ) 1 − y Y y N alloy films (0.72 b Ti/Al b 0.88) deposited at oblique vapour beam incidence and 500 °C (corresponding to zone T) in which mixed cubic TiN (c-TiN) and wurtzite AlN (w-AlN) structures were formed together with an unusual complex texture. The texture of c-TiN phase changed from 〈001〉 to b111N at a certain thickness forming a definite crossover. Moreover the c-TiNb111N and the w-AlN〈0001〉 crystals were epitaxially related with axes tilted to the direction of the vapour beam. Based on a comprehensive transmission electron microscopy (TEM) and diffraction (XRD and selected area electron diffraction (SAED)) structure and morphology analysis, we discovered the details of this exotic structure making it possible to construct the complex pathway of structure evolution including the formation of the w-AlN phase and the change of the dominating texture of c-TiN phase with thickness in dependence of the Ti/Al ratio and the deposition parameters. This pathway could be deduced from the fundamental phenomena of structure formation and may be generalised for multi-component thin film systems. A composition structure zone model has been also proposed for the (Ti 1 − x Al x ) 1 − y Y y N thin film system in the 0 b x b 1 composition range

Анализ причин возникновения врожденных пороков сердца у новорожденных по данным ВДОКБ

ПОРОКИ СЕРДЦА ВРОЖДЕННЫЕСЕРДЕЧНО-СОСУДИСТЫЕ АНОМАЛИИСЕРДЦА БОЛЕЗНИНОВОРОЖДЕННЫЙ, БОЛЕЗН

Large differences in carbohydrate degradation and transport potential among lichen fungal symbionts.

Lichen symbioses are thought to be stabilized by the transfer of fixed carbon from a photosynthesizing symbiont to a fungus. In other fungal symbioses, carbohydrate subsidies correlate with reductions in plant cell wall-degrading enzymes, but whether this is true of lichen fungal symbionts (LFSs) is unknown. Here, we predict genes encoding carbohydrate-active enzymes (CAZymes) and sugar transporters in 46 genomes from the Lecanoromycetes, the largest extant clade of LFSs. All LFSs possess a robust CAZyme arsenal including enzymes acting on cellulose and hemicellulose, confirmed by experimental assays. However, the number of genes and predicted functions of CAZymes vary widely, with some fungal symbionts possessing arsenals on par with well-known saprotrophic fungi. These results suggest that stable fungal association with a phototroph does not in itself result in fungal CAZyme loss, and lends support to long-standing hypotheses that some lichens may augment fixed CO2 with carbon from external sources