Morphological and microstructural characterization of laser-glazedplasma-sprayed thermal barrier coatings

Laser glazing has been revealing a high potential for the improvement of plasma-sprayed (PS) thermal barrier coatings (TBCs) by reducing surface roughness, eliminating open porosity on the surface and generating a controlled segmented crack network, although the relationship of the processing parameters with the resultant properties has not yet been completely established. In this investigation, TBCs consisting of atmospheric plasma-sprayed (APS) ZrO2–8wt.%Y2O3 were subjected to a CO2 continuous wave laser-glazing process in order to seal its surface porosity, generating an external dense layer. For that purpose, different amounts of radiation resulting from different scanning speeds were applied to the specimens as well as different track overlapping. Results have shown a significant decrease of the surface roughness after the laser treatment. All specimens presented a fully dense and porous free external layer with a polyfaceted columnar microstructure highly adherent to the plasma-sprayed coating. Controlled surface crack networks, extremely dependent on the laser scanning speed and track overlapping, were achieved for each set of processing parameters. The cracks were found to have a tendency to be oriented in two perpendicular directions, one in the direction of the laser-beam travel direction, the other perpendicular to it. Moreover, the cracks parallel to the beam travel direction are found to be on the overlapping zone, coinciding with the edge of the subsequent track. The cracks are perpendicular to the surface along the densified layer and tend to branch and deviate from the vertical direction below it, within the porous PS coating. XRD results revealed mainly tV nontransformable tetragonal zirconia with a small percentage of residual monoclinic zirconia for the as-sprayed coating. All glazed coatings presented only tV nontransformable tetragonal zirconia with some variations on preferable crystal orientation. Grain sizes varied from 26 to 52 nm, increasing with an increase of laserirradiated energy; microstrain behaved inversely.Fundação para a Ciência e a Tecnologia (FCT) - Project POCTI/CTM/44590/2002.União Europeia (UE). Fundo Europeu de Desenvolvimento Regional (FEDER)

A single bacterial genus maintains root growth in a complex microbiome

Plants grow within a complex web of species that interact with each other and with the plant1–10. These interactions are governed by a wide repertoire of chemical signals, and the resulting chemical landscape of the rhizosphere can strongly affect root health and development7–9,11–18. Here, to understand how interactions between microorganisms influence root growth in Arabidopsis, we established a model system for interactions between plants, microorganisms and the environment. We inoculated seedlings with a 185-member bacterial synthetic community, manipulated the abiotic environment and measured bacterial colonization of the plant. This enabled us to classify the synthetic community into four modules of co-occurring strains. We deconstructed the synthetic community on the basis of these modules, and identified interactions between microorganisms that determine root phenotype. These interactions primarily involve a single bacterial genus (Variovorax), which completely reverses the severe inhibition of root growth that is induced by a wide diversity of bacterial strains as well as by the entire 185-member community. We demonstrate that Variovorax manipulates plant hormone levels to balance the effects of our ecologically realistic synthetic root community on root growth. We identify an auxin-degradation operon that is conserved in all available genomes of Variovorax and is necessary and sufficient for the reversion of root growth inhibition. Therefore, metabolic signal interference shapes bacteria–plant communication networks and is essential for maintaining the stereotypic developmental programme of the root. Optimizing the feedbacks that shape chemical interaction networks in the rhizosphere provides a promising ecological strategy for developing more resilient and productive crops

HASTE INTRAMEDULAR DE POLIPROPILENO, COMBINADA OU NÃO A BIOMATERIAIS, NO TRATAMENTO DE FRATURAS INDUZIDAS NO ÚMERO DE POMBOS

O trabalho teve por objetivo avaliar a utilização da haste intramedular de polipropileno, combinada ou não a biomateriais de origem bovina, no tratamento de fraturas transversas induzidas no terço médio do úmero direito de pombos-domésticos. No grupo I (n=7), a fratura foi estabilizada por meio de haste intramedular de polipropileno aplicada em ambos os fragmentos da fratura, sem ultrapassar as articulações. No grupo II (n=7) utilizou-se a mesma fixação, porém foi aplicado junto ao foco de fratura uma mistura de biomateriais, constituída de proteínas morfogenéticas do osso e aglutinante de colágeno liofilizado. Em ambos os grupos, a asa foi imobilizada junto ao corpo com bandagem em forma de 8 por um período de 30 dias. Com seis semanas de pós-operatório, cinco fraturas do grupo I e quatro do grupo II estavam totalmente consolidadas. Foram observadas uma não consolidação hipertrófica (grupo I) e duas não consolidações com deslocamento do eixo ósseo (grupo II). Exceto as três aves que apresentaram complicações nas fraturas, as demais recuperaram a capacidade de vôo. Foi possível concluir que a haste intramedular de polipropileno foi um método de imobilização de eficácia limitada e os biomateriais utilizados não estimularam a consolidação das fraturas. Use of polypropylene intramedullary rod alone or combined with biomaterials for treatment of induced humeral transverse fractures in pigeons Abstract The aim of this study was to evaluate a polypropylene intramedullary rod alone or combined with biomaterials from bovine origin for the treatment of transverse fractures induced in the midshaft of right humerus in pigeons. In group I (n=7) the fracture was immobilized using a polypropylene intramedullary rod inserted into both fractured extremities without entering the joints. The same device was used in group II (n=7). Additionally, the fractured site in group II animals received a mixture of biomaterials composed by bone morphogenetic proteins and lyophilized collagen. In both groups a cast was applied to the affected wing, which was immobilized with a figure-of-8 bandage applied to the body and wing during 30 days. Complete healing was observed after six weeks of surgery in five and four animals from groups I and II, respectively. Observed complications included one hypertrophic nonunion (group I) and two nonunion with bone shaft dislocation (group II). Except for the three pigeons that showed postoperative complications, the remaining animals recovered the ability of flight. It was possible to conclude that the polypropylene intramedullary rod is a limited method of immobilization and the biomaterials used in this study did not stimulate fracture healing

Glucocorticoid-induced leucine zipper modulates macrophage polarization and apoptotic cell clearance.

Macrophages are professional phagocytes that display remarkable plasticity, with a range of phenotypes that can be broadly characterized by the M1/M2 dichotomy. Glucocorticoid (GC)-induced leucine zipper (GILZ) is a protein known to mediate anti-inflammatory and some pro-resolving actions, including as neutrophil apoptosis. However, the role of GILZ in key macrophage function is not well understood. Here, we investigated the role of GILZ on macrophage reprogramming and efferocytosis. Using murine bone-marrow-derived macrophages (BMDMs), we found that GILZ was expressed in naive BMDMs and exhibited increased expression in M2-like macrophages (IL4-differentiated). M1-like macrophages (IFN/LPS-differentiated) from GILZ-/- mice showed higher expression of the M1 markers CD86, MHC class II, iNOS, IL-6 and TNF-α, associated with increased levels of phosphorylated STAT1 and lower IL-10 levels, compared to M1-differentiated cells from WT mice. There were no changes in the M2 markers CD206 and arginase-1 in macrophages from GILZ-/- mice differentiated with IL-4, compared to cells from WT animals. Treatment of M1-like macrophages with TAT-GILZ, a cell-permeable GILZ fusion protein, decreased the levels of CD86 and MHC class II in M1-like macrophages without modifying CD206 levels in M2-like macrophages. In line with the in vitro data, increased numbers of M1-like macrophages were found into the pleural cavity of GILZ-/- mice after LPS-injection, compared to WT mice. Moreover, efferocytosis was defective in the context of GILZ deficiency, both in vitro and in vivo. Conversely, treatment of LPS-injected mice with TAT-GILZ promoted inflammation resolution, associated with lower numbers of M1-like macrophages and increased efferocytosis. Collectively, these data indicate that GILZ is a regulator of important macrophage functions, contributing to macrophage reprogramming and efferocytosis, both key steps for the resolution of inflammation

Corneal thickness measurements in ovines with ultrasonic pachymetry and noncontact specular microscopy

O propósito do presente trabalho foi avaliar os valores da espessura corneana central em córneas de ovinos sadios com o microscópio especular de não-contato e paquímetro ultra-sônico. A espessura corneana central foi determinada em 22 olhos de 11 ovinos, inicialmente com microscópio especular de não-contato (Topcon SP-2000P), seguido pelo paquímetro ultra-sônico (Nidek UP-1000). Os valores médios das medidas corneanas centrais foram 654mm e 665mm com o microscópio especular de não contato e o paquímetro ultra-sônico, respectivamente. As medidas da espessura corneana demonstraram que ambos os instrumentos são confiáveis.The purpose of this study was to evaluate the central corneal thickness values in normal ovine with Topcon SP-2000P noncontact specular microscope and ultrasonic pachymeter. Central corneal thickness was detemined in 22 eyes of 11 ovines, first with a noncontact specular microscopy (Topcon SP-2000P), then using an ultrasonic pachgmeter (Nidek UP-1000). The central corneal measurements were 654mm e 665mm with Topcon and ultrasonic pachymeter, respectively. The instruments were reliable in their measurements

The Plant Microbiome: From Ecology to Reductionism and beyond

Methodological advances over the past two decades have propelled plant microbiome research, allowing the field to comprehensively test ideas proposed over a century ago and generate many new hypotheses. Studying the distribution of microbial taxa and genes across plant habitats has revealed the importance of various ecological and evolutionary forces shaping plant microbiota. In particular, selection imposed by plant habitats strongly shapes the diversity and composition of microbiota and leads to microbial adaptation associated with navigating the plant immune system and utilizing plant-derived resources. Reductionist approaches have demonstrated that the interaction between plant immunity and the plant microbiome is, in fact, bidirectional and that plants, microbiota, and the environment shape a complex chemical dialogue that collectively orchestrates the plant microbiome. The next stage in plant microbiome research will require the integration of ecological and reductionist approaches to establish a general understanding of the assembly and function in both natural and managed environments

Thickness and density of corneal endothelial cells in ovines

The cornea is transparent layer of the eye, transmission and refraction of light being their main functions. The endothelium, one of the cornea four layers, is a hexagonal unicellular layer that forms a barrier between the stroma and aqueous humor, obstructing the entrance of water and others solutes from the anterior chamber towards the stroma. In the regard to it, a minimum density of these cells is necessary to maintain the performance and clarity of the eye visual capacity. The main objective of the present research was the determination of the density of endothelial cells and their corneal thickness, using a noncontact specular microscope, in 22 eyes from 11 ovines. The average density of the endothelial corneal was 2726 cels/mm² and the thickness 654 µm. The males displayed a higher average density and a smaller cell area than the females.A córnea é transparente, sendo suas principais funções a transmissão e a refração da luz. Compreende quatro camadas, dentre elas, o endotélio corneano, que é constituído por uma única camada de células hexagonais interligadas, formando uma barreira entre o estroma corneano e o humor aquoso, limitando a entrada de água e solutos oriundos da câmara anterior para o estroma. Portanto, uma densidade mínima é necessária para manter a transparência e a funcionalidade corneanas. Objetivou-se determinar a densidade de células endoteliais e a espessura corneanas, utilizando-se microscopia especular de não contato, em 22 olhos provenientes de 11 ovinos. A média de densidade celular endotelial corneana foi de 2726 céls/mm2 e a espessura 654 µm. Os machos apresentaram médias de densidades superiores e áreas celulares inferiores em relação às fêmeas

Evaluation of laser-glazed plasma-sprayed thermal barriercoatings under high temperature exposure to molten salts

Thermal Barrier Coating (TBC) systems are frequently used in gas turbine engines to provide thermal insulation to the hot-section metallic components and also to protect them from oxidation, hot corrosion and erosion. Surface sealing treatments, namely laser-glazing, have been showing a high potential for extending in-service lifetimes of these systems by improving chemical and thermo-mechanical resistance. In this investigation, both as-sprayed and laser-glazed TBCs were exposed to hot corrosion in molten salts. The glazed coatings were obtained by scanning the surface of the plasma-sprayed coatings with either a CO2 or a Nd:YAG laser. The hot corrosion investigation was accomplished by subjecting the specimens to an isothermal air furnace testing under V2O5 and/or Na2SO4 at a temperature of 1000 °C for 100 h. Spallation has been observed in coatings in the as-sprayed condition under V2O5 or V2O5+Na2SO4. Na2SO4 itself had no or minimal effect on the degradation of the laser-glazed or as-sprayed condition coatings, respectively. The degradation in V2O5 was accomplished by destabilization of YSZ as a consequence of depletion of yttria from the solid solution to form YVO4 and therefore led to the disruptive transformation of the metastable tetragonal phase to the monoclinic phase. Moreover, the presence of both corrosive salts induced the formation of large high aspect ratio YVO4 crystals that introduced additional stresses and contributed to the degradation of the coatings. The laser-glazed specimens were not efficient in avoiding the molten salt penetration along the thickness direction due to the presence of cracks on the glazed layer. However due to a reduced specific surface area of the dense glazed layer, the corrosion reaction of the molten salts with the YSZ has been lower than in coatings in the assprayed condition.Fundo Europeu de Desenvolvimento Regional(FEDER) - Programa Operacional "Ciência, Tecnologia e Inovação" (POCTI).Fundação para a Ciência e a Tecnologia (FCT) - Project POCTI/CTM/ 44590/2002