673 research outputs found
Modelling phase-assemblage diagrams for magnesian metapelites in the system K2O-FeO-MgO-Al2O3-SiO2-H2O: geodynamic consequences for the Monte Rosa nappe, Western Alps
Magnesian metamorphic rocks with metapelitic mineral assemblage and composition are of great interest in metamorphic petrology for their ability to constrain P-T conditions in terranes where metamorphism is not easily visible. Phase-assemblage diagrams for natural and model magnesian metapelites in the system KFMASH are presented to document how phase relationships respond to water activity, bulk composition, pressure and temperature. The phase assemblages displayed on these phase diagrams are consistent with natural mineral assemblages occurring in magnesian metapelites. It is shown that the equilibrium assemblages at high pressure conditions are very sensitive to a(H2O). Specifically, the appearance of the characteristic HP assemblage chloritoid-talc-phengite-quartz (with excess H2O) in the magnesian metapelites of the Monte Rosa nappe (Western Alps) is due to the reduction of a(H2O). Furthermore, the mineral assemblages are determined by the whole-rock FeO/(FeO+MgO) ratio and effective Al content X A as well as P and T. The predicted mineral associations for the low- and high-X A model bulk compositions of magnesian metapelites at high pressure are not dependent on the X A variations as they show a similar sequence of mineral assemblages. Above 20kbar, the prograde sequence of assemblages associated with phengite (with excess SiO2 and H2O) for low- and high-X A bulk compositions of magnesian metapelites is: carpholite-chlorite→chlorite-chloritoid→chloritoid-talc→chloritoid-talc-kyanite→ talc-garnet-kyanite→garnet-kyanite±biotite. At low to medium P-T conditions, a low-X A stabilises the phengite-bearing assemblages associated with chlorite, chlorite+K-feldspar and chlorite+biotite while a high-X A results in the chlorite-phengite bearing assemblages associated with pyrophyllite, andalusite, kyanite and carpholite. A high-X A magnesian metapelite with nearly iron-free content stabilises the talc-kyanite-phengite assemblage at moderate to high P-T conditions. Taking into account the effective bulk composition and a(H2O) involved in the metamorphic history, the phase-assemblage diagrams presented here may be applied to all magnesian metapelites that have compositions within the system KFMASH and therefore may contribute to gaining insights into the metamorphic evolution of terranes. As an example, the magnesian metapelites of the Monte Rosa nappe have been investigated, and an exhumation path with P-T conditions for the western roof of the Monte Rosa nappe has been derived for the first time. The exhumation shows first a near-isothermal decompression from the Alpine eclogite peak conditions around 24kbar and 505°C down to approximately 8kbar and 475°C followed by a second decompression with concomitant coolin
Impact of short-acting vs. standard anaesthetic agents on obstructive sleep apnoea: a randomised, controlled, triple-blind trial.
Sleep apnoea is associated with negative outcomes following general anaesthesia. Current recommendations suggest using short-acting anaesthetic agents in preference to standard agents to reduce this risk, but there is currently no evidence to support this. This randomised controlled triple-blind trial tested the hypothesis that a combination of short-acting agents (desflurane-remifentanil) would reduce the postoperative impact of general anaesthesia on sleep apnoea severity compared with standard agents (sevoflurane-fentanyl). Sixty patients undergoing hip arthroplasty under general anaesthesia were randomised to anaesthesia with desflurane-remifentanil or sevoflurane-fentanyl. Respiratory polygraphy was performed before surgery and on the first and third postoperative nights. The primary outcome was the supine apnoea-hypopnoea index on the first postoperative night. Secondary outcomes were the supine apnoea-hypopnoea index on the third postoperative night, and the oxygen desaturation index on the first and third postoperative nights. Additional outcomes included intravenous morphine equivalent consumption and pain scores on postoperative days 1, 2 and 3. Pre-operative sleep study data were similar between groups. Mean (95%CI) values for the supine apnoea-hypopnoea index on the first postoperative night were 18.9 (12.7-25.0) and 21.4 (14.2-28.7) events.h <sup>-1</sup> , respectively, in the short-acting and standard anaesthesia groups (p = 0.64). Corresponding values on the third postoperative night were 28.1 (15.8-40.3) and 38.0 (18.3-57.6) events.h <sup>-1</sup> (p = 0.34). Secondary sleep- and pain-related outcomes were generally similar in the two groups. In conclusion, short-acting anaesthetic agents did not reduce the impact of general anaesthesia on sleep apnoea severity compared with standard agents. These data should prompt an update of current recommendations
Influence of Parapets on Wave Overtopping on Mound Breakwaters with Crown Walls
[EN] Background literature on the influence of parapets on the overtopping of mound breakwaters is limited. In this study, numerical tests were conducted using computational fluid dynamics (CFD) to analyze the influence of nine crown wall geometries (seven with parapets). The CFD model was implemented in OpenFOAM((R)) and successfully validated with laboratory tests. A new estimator of the dimensionless mean wave-overtopping discharges (logQ) on structures with parapets is proposed. The new estimator depends on the estimation of logQ of the same structure without a parapet. The effects on wave overtopping of the parapet angle (epsilon(p)), parapet width (w(p)), and parapet height (h(p)) were analyzed. Low values of epsilon(p) and w(p)/h(p) approximate to 1 produced the highest parapet effectiveness to reduce the mean wave-overtopping discharges.This research was funded by Universitat Politecnica de Valencia (Grant SP20180111, Primeros Proyectos de Investigacion (PAID-06-18), Vicerrectorado de Investigacion, Innovacion y Transferencia de la Universitat Politecnica de Valencia). The authors are grateful for financial support from European FEDER and Spanish Ministerio de Economía y Competitividad (Grant RTI2018-101073-B-I00), SATO (OHL Group). The authors acknowledge the support provided by the postdoctoral company internship program AEST granted to Jorge Molines by Generalitat Valenciana (Grant AEST/2019/004) and by the postdoctoral program APOSTD granted to Arnau Bayon by Generalitat Valenciana (Grant APOSTD/2019/100).Molines, J.; Bayón, A.; Gómez-Martín, ME.; Medina, JR. (2019). Influence of Parapets on Wave Overtopping on Mound Breakwaters with Crown Walls. 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Soil Phosphorus Uptake by Continuously Cropped Lupinus albus: A New Microcosm Design
When grown in soils with sparingly available phosphorus (P), white lupin (Lupinus albus L.) forms special root structures, called cluster roots, which secrete large amounts of organic acids and concomitantly acidify the rhizosphere. Many studies dealing with the understanding of this P acquisition strategy have been performed in short time experiments either in hydroponic cultures or in small microcosm designs with sand or sand:soil mixtures. In the present study, we applied an experimental design which came nearer to the natural field conditions: we performed a one-year experiment on large microcosms containing 7kg of soil and allowing separation of rhizosphere soil and bulk soil. We planted six successive generations of lupins and analysed P uptake, organic P desorption, phosphatase activities and organic acid concentrations in different soil samples along a spatio-temporal gradient. We compared the rhizosphere soil samples of cluster (RSC) and non-cluster roots (RSNC) as well as the bulk soil (BS) samples. A total shoot biomass of 55.69 ± 1.51g(d.w.)y−1 was produced and P uptake reached 220.59 ± 5.99mgy−1. More P was desorbed from RSC than from RSNC or BS (P < 0.05). RSC and RSNC showed a higher activity of acid and alkaline phosphatases than BS samples and a higher acid phosphatase activity was observed in RSC than in RSNC throughout the one-year experiment. Fumarate was the most abundant organic acid in all rhizosphere soil samples. Citrate was only present in detectable amounts in RSC while malate and fumarate were recovered from both RSC and RSNC. Almost no organic acids could be detected in the BS samples. Our results demonstrated that over a one-year cultivation period in the absence of an external P supply, white lupin was able to acquire phosphate from the soil and that the processes leading to this P uptake took place preferentially in the rhizosphere of cluster root
CIVA Workstation for NDE: Mixing of NDE Techniques and Modeling
Non Destructive Examination (NDE) plays an important role in numerous industrial fields. They are used both in production tests (improvement of product quality, process monitoring) and in facility inspections (installation safety, component life times). Various types of inspections are widely used: radiography, ultrasonics, eddy currents, etc. The choice of an inspection technique is made on the basis of different criteria: type of material to be tested, type of defects sought, detection or characterization, inspection time and cost. In some cases, either to compare the capabilities of different techniques, or to use complementary inspection methods, the same components are examined with different procedures. In these cases, it is very useful to have a single evaluation tool allowing direct comparison of the methods. This tool is indispensable for directly convoluting signals from two inspection methods.</p
Prevalence, clinical management and risks associated with acute faecal incontinence in the critical care setting: the FIRST questionnaire survey
Design and characterization of synthetic biodegradable films for musculoskeletal tissue engineering
To repair soft tissue, it is vital to ensure that the biomaterial is able to mimic the complex elasticity of the native tissue. It has been demonstrated that substrate stiffness has a huge influence on cellular growth, differentiation, motility and phenotype maintenance. The goal of the present study is to characterize extensively a set of polymeric films with variable mechanical profiles. A range of synthetic biodegradable polymers was selected according to the physico-chemical intrinsic properties of aliphatic polymers. They have similar chemistry (absorbable polyesters made from lactic acid, glycolic acid, trimethylene carbonate, dioxanone & β-caprolactone), however show different mechanical and degradation properties. The films were manufactured by thermal presser and then characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties of the films were assessed by uniaxial tensile tests in wet conditions and also by atomic force microscopy (AFM) to assess the material's stiffness at a micro-level. In vitro assays were performed to assess the cell cytocompatibility, proliferation and differentiation potential of the films. The mechanical properties of the materials are within the range intended for musculoskeletal tissue repair. Biological assays showed good cell adhesion, cell proliferation and cell viability. Stem cells were able to differentiate into adipogenic, osteogenic, chondrogenic and tenogenic lineages. Overall the selection of polymers gave good options for a potential tissue repair scaffold. In the future, the combined effect of stiffness and topography will be assessed on cell phenotype maintenance
Development and characterisation of cytocompatible polyester substrates with tunable mechanical properties and degradation rate
Although it has been repeatedly indicated the importance to develop implantable devices and cell culture substrates with tissue-specific rigidity, current commercially available products, in particular cell culture substrates, have rigidity values well above most tissues in the body. Herein, six resorbable polyester films were fabricated using compression moulding with a thermal presser into films with tailored stiffness by appropriately selecting the ratio of their building up monomers (e.g. lactide, glycolide, trimethylene carbonate, dioxanone, ε-caprolactone). Typical NMR and FTIR spectra were obtained, suggesting that the fabrication process did not have a negative effect on the conformation of the polymers. Surface roughness analysis revealed no apparent differences between the films as a function of polymer composition. Subject to polymer composition, polymeric films were obtained with glass transition temperatures from -52 °C to 61 °C; contact angles in water from 81 ° to 94 °; storage modulus from 108 MPa to 2,756 MPa and loss modulus from 8 MPa to 507 MPa (both in wet state, at 1 Hz frequency and at 37 °C); ultimate tensile strength from 8 MPa to 62 MPa, toughness from 23 MJ/m3 to 287 MJ/m3, strain at break from 3 % to 278 %, macro-scale Young's modulus from 110 MPa to 2,184 MPa (all in wet state); and nano-scale Young's modulus from 6 kPa to 15,019 kPa (in wet state). With respect to in vitro degradation in phosphate buffered saline at 37 °C, some polymeric films [e.g. poly(glycolide-lactide) 30 / 70] started degrading from day 7 (shortest timepoint assessed), whilst others [e.g. poly(glycolide-co-ε-caprolactone) 10 / 90] were more resilient to degradation up to day 21 (longest timepoint assessed). In vitro biological analysis using human dermal fibroblasts and a human monocyte cell line (THP-1) showed the potential of the polymeric films to support cell growth and controlled immune response. Evidently, the selected polymers exhibited properties suitable for a range of clinical indications.This work has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie, grant agreement no. 676338; the Widespread: Twinning, grant agreement no. 810850; and the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, grant agreement no. 866126. This work was also supported by Science Foundation Ireland, Career Development Award, grant agreement no. 15/CDA/3629 and Science Foundation Ireland/European Regional Development Fund, grant agreement no. 13/RC/2073. We would also like to thank Darlene Nebinger, Danielle Lord and Oswaldo Fabian from Medtronic North Haven, USA, for all their technical/experimental support
Combined pangenomics and transcriptomics reveals core and redundant virulence processes in a rapidly evolving fungal plant pathogen
Background
Studying genomic variation in rapidly evolving pathogens potentially enables identification of genes supporting their “core biology”, being present, functional and expressed by all strains or “flexible biology”, varying between strains. Genes supporting flexible biology may be considered to be “accessory”, whilst the “core” gene set is likely to be important for common features of a pathogen species biology, including virulence on all host genotypes. The wheat-pathogenic fungus Zymoseptoria tritici represents one of the most rapidly evolving threats to global food security and was the focus of this study.
Results
We constructed a pangenome of 18 European field isolates, with 12 also subjected to RNAseq transcription profiling during infection. Combining this data, we predicted a “core” gene set comprising 9807 sequences which were; (1) present in all isolates; (2) lacking inactivating polymorphisms; and (3) expressed by all isolates. A large accessory genome, consisting of 45% of the total genes was also defined. We classified genetic and genomic polymorphism at both chromosomal and individual gene scales. Proteins required for essential functions including virulence, had lower-than average sequence variability amongst core genes. Both core and accessory genomes encoded many small, secreted candidate effector proteins that likely interact with plant immunity. Viral vector-mediated transient in planta overexpression of 88 candidates failed to identify any which induced leaf necrosis characteristic of disease. However, functional complementation of a non-pathogenic deletion mutant lacking five core genes, demonstrated that full virulence was restored by re-introduction of the single gene exhibiting least sequence polymorphism and highest expression.
Conclusions
These data support the combined use of pangenomics and transcriptomics for defining genes which represent core, and potentially exploitable, weaknesses in rapidly evolving pathogens
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