Numerical simulation of scour below pipelines using flexible mesh methods

Evaluating bed morphological structure and evolution (specifically the scoured bed level) accurately using numerical models is critical for analyses of the stability of many marine structures. This paper discusses the performance of an implementation within Fluidity, an open source, general purpose, computational fluid dynamics (CFD) code, capable of handling arbitrary multi-scale unstructured tetrahedral meshes and including algorithms to perform dynamic anisotropic mesh adaptivity. The flexibility over mesh structure and resolution that these capabilities provide makes it potentially highly suitable for coupling the structural scale with larger scale ocean dynamics. In this very preliminary study the solver approach is demonstrated for an idealised scenario. Discontinuous Galerkin finite-element (DG-FEM) based discretisation methods have been used for the hydrodynamics and morphological calculations, and automatic mesh deformation has been utilised to account for bed evolution changes while preserving the validity and quality of the mesh. In future work, the solver will be used in three-dimensional impinging jet and other industrial and environmental scour studies

Zr alloy protection against high-temperature oxidation: Coating by a double-layered structure with active and passive functional properties

In this work, a new concept of metal surface protection against degradation caused by high-temperature oxidation in water environment is presented. We were the first to create a double-layered coating consisting of an active and passive part to protect Zr alloy surface against high-temperature oxidation in a hot water environment. We investigated the hot steam corrosion of ZIRLO fuel cladding coated with a double layer consisting of 500 nm nanocrystalline diamond (NCD) as the bottom layer and 2 m chromium-aluminum-silicon nitride (CrAlSiN) as the upper layer. Coated and noncoated ZIRLO samples were exposed for 4 days at 400 °C in an autoclave (working water-cooled nuclear reactor temperature) and for 60 minutes at 1000 °C (nuclear reactor accident temperature) in a hot steam furnace. We have shown that the NCD coating protects the Zr alloy surface against oxidation in an active way: carbon from NCD layer enters the Zr alloy surface and, by changing the physical and chemical properties of the Zr cladding tube surface, limits the Zr oxidation process. In contrast, the passive CrAlSiN coating prevents the Zr cladding tube surface from coming into physical contact with the hot steam. The advantages of the double layer were demonstrated, particularly in terms of hot (accident-temperature) oxidation kinetics: in the initial stage, CrAlSiN layer with low number of defects acts as an impermeable barrier. But after a longer time (more than 20 minutes) the protection by more cracked CrAlSiN decreases. At the same time, the carbon from NCD strongly penetrates the Zr cladding surface and worsen conditions for Zr oxidation. For the double-layer coating, the underlying NCD layer mitigates thermal expansion, reducing cracks and defects in upper layer CrAlSiN

Outcomes and associated risk factors of patients traced after being lost to follow-up from antiretroviral treatment in Lilongwe, Malawi

Abstract Background Loss to follow-up is a major challenge of antiretroviral treatment (ART) programs in sub-Saharan Africa. Our objective was to a) determine true outcomes of patients lost to follow-up (LTFU) and b) identify risk factors associated with successful tracing and deaths of patients LTFU from ART in a large public sector clinic in Lilongwe, Malawi. Methods Patients who were more than 2 weeks late according to their last ART supply and who provided a phone number or address in Lilongwe were eligible for tracing. Their outcomes were updated and risk factors for successful tracing and death were examined. Results Of 1800 patients LTFU with consent for tracing, 724 (40%) were eligible and tracing was successful in 534 (74%): 285 (53%) were found to be alive and on ART; 32 (6%) had stopped ART; and 217 (41%) had died. Having a phone contact doubled tracing success (adjusted odds ratio, aOR = 2.1, 95% CI 1.4-3.0) and odds of identifying deaths [aOR = 1.8 (1.2-2.7)] in patients successfully traced. Mortality was higher when ART was fee-based at initiation (aOR = 2.3, 95% CI 1.1-4.7) and declined with follow-up time on ART. Limiting the analysis to patients living in Lilongwe did not change the main findings. Conclusion Ascertainment of contact information is a prerequisite for tracing, which can reveal outcomes of a large proportion of patients LTFU. Having a phone contact number is critical for successful tracing, but further research should focus on understanding whether phone tracing is associated with any differential reporting of mortality or LTFU

Bovine pericardium retail preserved in glutaraldehyde and used as a vascular patch

<p>Abstract</p> <p>Background</p> <p>In this study we evaluated the performance of bovine pericardium preserved in glutaraldehyde used as a vascular patch.</p> <p>Methods</p> <p>Fourteen young pigs, six females and eight males, weighting 10.3 - 18.4 kg were used in our study. We implanted three remnants in each pig, two in the abdominal aorta and one was juxtaposed to the peritoneum. The smooth face (SF) and rough face (RF) of each remnant were implanted turned to the vessel inner portion and one remnant was juxtaposed to the peritoneum. The animals were sacrificed in 4.5 - 8 months after surgery (75 - 109 kg). The remnants were assessed for aorta wall, fibroses formation in inner apposition and calcification related to the face turned to the vessel inner portion.</p> <p>Results</p> <p>The rough face showed a lower dilatation level compared to the face implanted in adjacent aorta. There was no difference between intensity and/or incidence of graft calcification when the superficies were compared. The bovine pericardium preserved in glutaraldehyde did not show alterations in its structure when implanted with different faces turned to the inner portion of vessel.</p> <p>Conclusion</p> <p>When turned to the inner portion of the vessel, the rough face of the remnant presented a lower dilatation in relation to the adjacent aorta and a better quality of endothelium layer and did not show a difference between intensity and/or incidence of graft calcification.</p

Phage Encoded H-NS: A Potential Achilles Heel in the Bacterial Defence System

The relationship between phage and their microbial hosts is difficult to elucidate in complex natural ecosystems. Engineered systems performing enhanced biological phosphorus removal (EBPR), offer stable, lower complexity communities for studying phage-host interactions. Here, metagenomic data from an EBPR reactor dominated by Candidatus Accumulibacter phosphatis (CAP), led to the recovery of three complete and six partial phage genomes. Heat-stable nucleoid structuring (H-NS) protein, a global transcriptional repressor in bacteria, was identified in one of the complete phage genomes (EPV1), and was most similar to a homolog in CAP. We infer that EPV1 is a CAP-specific phage and has the potential to repress up to 6% of host genes based on the presence of putative H-NS binding sites in the CAP genome. These genes include CRISPR associated proteins and a Type III restriction-modification system, which are key host defense mechanisms against phage infection. Further, EPV1 was the only member of the phage community found in an EBPR microbial metagenome collected seven months prior. We propose that EPV1 laterally acquired H-NS from CAP providing it with a means to reduce bacterial defenses, a selective advantage over other phage in the EBPR system. Phage encoded H-NS could constitute a previously unrecognized weapon in the phage-host arms race

Identification of stable QTLs for vegetative and reproductive traits in the microvine (Vitis vinifera L.) using the 18 K Infinium chip

UMR AGAP - équipe DAAV - Diversité, adaptation et amélioration de la vigne[b]Background[/b] [br/]The increasing temperature associated with climate change impacts grapevine phenology and development with critical effects on grape yield and composition. Plant breeding has the potential to deliver new cultivars with stable yield and quality under warmer climate conditions, but this requires the identification of stable genetic determinants. This study tested the potentialities of the microvine to boost genetics in grapevine. A mapping population of 129 microvines derived from Picovine x Ugni Blanc flb, was genotyped with the Illumina® 18 K SNP (Single Nucleotide Polymorphism) chip. Forty-three vegetative and reproductive traits were phenotyped outdoors over four cropping cycles, and a subset of 22 traits over two cropping cycles in growth rooms with two contrasted temperatures, in order to map stable QTLs (Quantitative Trait Loci). [br/][b]Results[/b] [br/]Ten stable QTLs for berry development and quality or leaf area were identified on the parental maps. A new major QTL explaining up to 44 % of total variance of berry weight was identified on chromosome 7 in Ugni Blanc flb, and co-localized with QTLs for seed number (up to 76 % total variance), major berry acids at green lag phase (up to 35 %), and other yield components (up to 25 %). In addition, a minor QTL for leaf area was found on chromosome 4 of the same parent. In contrast, only minor QTLs for berry acidity and leaf area could be found as moderately stable in Picovine. None of the transporters recently identified as mutated in low acidity apples or Cucurbits were included in the several hundreds of candidate genes underlying the above berry QTLs, which could be reduced to a few dozen candidate genes when a priori pertinent biological functions and organ specific expression were considered. [br/][b]Conclusions[/b] [br/]This study combining the use of microvine and a high throughput genotyping technology was innovative for grapevine genetics. It allowed the identification of 10 stable QTLs, including the first berry acidity QTLs reported so far in a Vitis vinifera intra-specific cross. Robustness of a set of QTLs was assessed with respect to temperature variatio

Estimating the changing disease burden attributable to smoking in South Africa for 2000, 2006 and 2012

Background. Ongoing quantification of the disease burden attributable to smoking is important to monitor and strengthen tobacco control policies. Objectives. To estimate the attributable burden due to smoking in South Africa for 2000, 2006 and 2012. Methods. We estimated attributable burden due to smoking for selected causes of death in South African (SA) adults aged ≥35 years for 2000, 2006 and 2012. We combined smoking prevalence results from 15 national surveys (1998 - 2017) and smoking impact ratios using national mortality rates. Relative risks between smoking and select causes of death were derived from local and international data. Results. Smoking prevalence declined from 25.0% in 1998 (40.5% in males, 10.9% in females) to 19.4% in 2012 (31.9% in males, 7.9% in females), but plateaued after 2010. In 2012 tobacco smoking caused an estimated 31 078 deaths (23 444 in males and 7 634 in females), accounting for 6.9% of total deaths of all ages (17.3% of deaths in adults aged ≥35 years), a 10.5% decline overall since 2000 (7% in males; 18% in females). Age-standardised mortality rates (and disability-adjusted life years (DALYs)) similarly declined in all population groups but remained high in the coloured population. Chronic obstructive pulmonary disease accounted for most tobacco-attributed deaths (6 373), followed by lung cancer (4 923), ischaemic heart disease (4 216), tuberculosis (2 326) and lower respiratory infections (1 950). The distribution of major causes of smoking-attributable deaths shows a middle- to high-income pattern in whites and Asians, and a middle- to low-income pattern in coloureds and black Africans. The role of infectious lung disease (TB and LRIs) has been underappreciated. These diseases comprised 21.0% of deaths among black Africans compared with only 4.3% among whites. It is concerning that smoking rates have plateaued since 2010. Conclusion. The gains achieved in reducing smoking prevalence in SA have been eroded since 2010. An increase in excise taxes is the most effective measure for reducing smoking prevalence. The advent of serious respiratory pandemics such as COVID-19 has increased the urgency of considering the role that smoking cessation/abstinence can play in the prevention of, and post-hospital recovery from, any condition