Simulation des transferts réactifs multi-constituants au sein des lits d’infiltration percolation – évaluation des capacités d’oxygénation

L’assainissement des eaux usées par infiltration percolation appartient à la filière de traitement des rejets polluants à cultures fixées. Dans un contexte géographique spécifique et pour une population avoisinant 500 à 1 000 équivalents habitants, elle paraît bien indiquée. Filière dite rustique, elle n’en est pas moins complexe. L’objectif de cette étude est de contribuer, à travers une simulation numérique, à la compréhension des phénomènes physiques et biochimiques qui s’établissent au sein d’un lit d’infiltration percolation. Les aspects essentiels à l’activité bactérienne que sont l’hydrodynamique du milieu poreux, le développement de la biomasse active, le transport, la consommation et les transferts d’oxygène y sont abordés. À travers des essais d’une vérification méthodique du modèle effectuée à partir des solutions analytiques, il ressort principalement que la dispersion hydrodynamique et le taux de dégradation ont des effets contraires sur le rendement d’abattement des charges polluantes. En outre, un résultat significatif obtenu est la comparaison qualitative et quantitative des apports convectifs et diffusifs en oxygène au sein des lits d’infiltration percolation qui sont à aération naturelle.Wastewater sanitation using infiltration/percolation is part of an approach that uses attached microorganisms to treat pollutant loads. It appears suitable for a specific geographical context, and for population equivalents of approximately 500-1000 people. The aim of this study was to improve, by means of a numerical simulation, the understanding of certain physical and biochemical phenomena observed within an infiltration/percolation bed. All the aspects essential to bacterial activity are examined, including: the hydrodynamics of the porous media; the development of an active biomass; transport; and oxygen transfer and consumption. The latter are of paramount importance in non-saturated porous media, where significant aeration can take place, whereas in saturated soils and aquifers containing nitrogenous and organic compounds, the oxygen in water is rapidly consumed.The model we have formulated includes seven equations, which describe macroscopic transport, and are coupled and non-linear. The terms “wells/sources” are functions of unknown variables. The resolution of the equations, obtained after discretization of the equations using Euler’s finite difference method, was performed using Thomas’ algorithm and Fortran 95 programming. We used an innovative approach: analytical solutions developed for saturated porous media were modified to take into account a heterogeneous flow field in a non-saturated porous medium. In a systematic approach, we tested two problems that are part of a gradual verification process: one-dimensional convection-dispersion solute without a kinetic reaction; one-dimensional solute with a first-order decay.The code we have developed insures a very good approximation of the solute transport within a non-saturated porous medium. For a given rate of flow and a given supply period, the greater the dispersion, the quicker the solute will become homogeneous. In other words, a very high dispersion will induce a very low residence time for the solute within the medium. In wastewater treatment within sand beds, the residence time or contact period between the pollutant matter transported by the effluent and the purifying biomass attached to the support is thus a parameter that is linked to the dispersion of the effluent within the medium. It also appears that the reduction in pollutant load is optimized within a biofilm with a high degradation rate, and for an effluent with a low dispersion coefficient. This result is coherent with the link between dispersion and residence time of the effluent in the system.We also examined the impact that the hydraulic load and the substrate content in the effluent have on the oxygenation capacities of a filtering mass. A qualitative and quantitative analysis of the incoming oxygen flow was performed. Thus we show that, at the beginning of the supply period, convection is more influential than diffusion. We also present several results from the simulations of substrate reduction profiles, which were very closely linked to oxygen content profiles. Thus we observed a rapid decrease in oxygen content due to intensive bacterial activity in the upper part of sand filters, followed by an increase in oxygen towards the bottom of the filter due to the absence of substrate. The main conclusion of this part of the study was that in order to optimize the ability for oxygenation within infiltration/percolation beds, it would be preferable to connect them to the separate sewer networks, which yield more concentrated effluents than do combined sewer networks

Five Fractions versus Seven Fractions SBRT for Intermediate- and High-Risk Prostate Cancer: A Propensity Score Matched Pair Analysis.

PURPOSE To compare two stereotactic body radiotherapy (SBRT) regimens in patients with intermediate- or high-risk prostate cancer with regards toxicity and efficacy. METHODS/MATERIAL We retrospectively collected data from 198 patients treated with SBRT for prostate cancer at two different institutions. Patients received either 35-36.25 Gy in five fractions (group A) using Cyberknife robotic platform or 42.7 Gy in seven fractions (group B) using a C-arm LINAC (image-guided). Propensity score matching was done (2:1 nearest neighbor matching without replacement), resulting in 120 patients (80 patients for group A, 40 patients for group B). Toxicity, PSA nadir, biochemical failure and disease-free survival (DFS) were analyzed. RESULTS Median follow up of all patients was 13 months (range 1-91 months). Overall, 23.3% of patients had ≥G2 acute GU toxicity (21.1% group A versus 30% group B (p = 0.222)) and 6.6% of patients ≥G2 GI toxicity (2.5% versus 15% (p = 0.010)). There was one acute G3 GU toxicity in arm A and one acute G4 rectal bleeding in group B (anticoagulated patient). Regarding late toxicity, 14.1% of patients had ≥G2 late GU toxicity (17.4% versus 6.6% (p = 0.159)) and 5.0% of patients had ≥G2 late GI toxicity (1.4% versus 13.3% (p = 0.013)). There was one G3 late GU toxicity in arm B and two G3 late GI toxicities, one in each arm. Relative median PSA reduction was 92.4% (-53.9-99.9%) from baseline PSA (93.7% (-53.9-99.9%) in group A versus 87.7% (39.8-99.9%) in group B (p = 0.043). In total, 4.2% of patients had biochemical relapse, 5.0% in group A and 2.5% in group B (p = 0.518). One-year DFS in the overall cohort was 97.3%, 98.8% in group A and 94.3% in group B (p = 0.318). CONCLUSION Both SBRT regimens have acceptable acute and late toxicity and good efficacy. There are significantly more GI toxicities in the seven-fraction regimen. Longer follow-up is warranted for better comparison of long-term efficacy

Method Of Use And The Contribution Of LES 3D Modeling To Reproduce Velocity Distribution In Compound Channels

Discharge determination in open channels is of great interest for water engineering, especially in compound channels where the main difficulty is the link between the measured velocity and the mean velocity. To do so, the 3D modeling is used as a tool to get the velocity distribution in compound channels. The purpose of this study is to compare through numerical simulations, the most common turbulence models such as K-epsilon and RSM to LES that is rarely used in this field, in order to show the efficiency of the LES model to reproduce the velocity distribution. The method used is the following: an experimental case (NEZU 1991) was modeled with RSM, k-epsilon, k-w sst and LES using two different software (Ansys Fluent® and OpenFoam®). Finally, for each model, the three parameters of the velocity U, V and W, the turbulence kinetic energy Tke and the Reynolds stress tensors were compared with the experimental case in order to identify the closest model to Nezu’s results. This research has found that for a certain limit (Re104), the RANS models coupled to Ansys Fluent® software can reproduce correctly neither the velocity distribution nor the secondary currents. This case represents a limit for the RANS models. In comparison the LES model allowed to display a good representation of velocity distribution, secondary currents and of the dip phenomenon. By using the recycling method (Castro 2011) to generate a turbulence inlet velocity, LES shows also the advantage of decreasing the number of grid cells the computational domain, which makes the computational time last less longer. Finally, contrary to the RANS model, the LES model gives information at each time step which allows the researcher to get details that are not provided by the RANS model such as the birth of turbulence in the main channel

Combined linkage and association mapping of putative QTLs controlling black tea quality and drought tolerance traits

The advancements in genotyping have opened new approaches for identification and precise mapping of quantitative trait loci (QTLs) in plants, particularly by combining linkage and association mapping (AM) analysis. In this study, a combination of linkage and the AM approach was used to identify and authenticate putative QTLs associated with black tea quality traits and percent relative water content (%RWC). The population structure analysis clustered two parents and their respective 261 F1 progenies from the two reciprocal crosses into two clusters with 141 tea accessions in cluster one and 122 tea accessions in cluster two. The two clusters were of mixed origin with tea accessions in population TRFK St. 504 clustering together with tea accessions in population TRFK St. 524. A total of 71 putative QTLs linked to black tea quality traits and %RWC were detected in interval mapping (IM) method and were used as cofactors in multiple QTL model (MQM) mapping where 46 putative QTLs were detected. The phenotypic variance for each QTL ranged from 2.8 to 23.3% in IM and 4.1 to 23% in MQM mapping. Using Q-model and Q + K-model in AM, a total of 49 DArTseq markers were associated with 16 phenotypic traits. Significant marker-trait association in AM were similar to those obtained in IM, and MQM mapping except for six more putative QTLs detected in AM which are involved in biosynthesis of secondary metabolites, carbon fixation and abiotic stress. The combined linkage and AM approach appears to have great potential to improve the selection of desirable traits in tea breeding.James Finlay (Kenya) Ltd., George Williamson (Kenya) Ltd., Sotik Tea Company (Kenya) Ltd., Mcleod Russell (Uganda) Ltd., the TRI of Kenya and Southern African Biochemistry and Informatics for Natural Products (SABINA) as well as the Technology and Human Resources for Industry Programme (THRIP), an initiative of the Department of Trade and Industries of South Africa (dti), the National Research Foundation (NRF) of South Africa, and the University of Pretoria (South Africa).https://www.springer.com/journal/106812020-09-11hj2020BiochemistryGeneticsMicrobiology and Plant Patholog

An experiment of a hydropower conversion system based on vortex-induced vibrations in a confined channel

A hydropower conversion system based on vortex-induced vibrations is investigated experimentally. It consists in a cylinder immerged in a low-velocity flow in a channel (under 1 m/s), which is linked to a variable stiffness spring, so that the natural frequency of the system might be controlled. Current studies report investigations on marine applications. Although rivers or channels constitute a strong energy potential, they are not exploited enough. In this paper, we will investigate the feasibility of such a system implantation in a confined flow in a channel, with important edge effects. We propose a study of the effects of a confined flow on the efficiency of the system. We will highlight feasible improvements, particularly through automatic control strategies (generator behaviour, system's natural frequency). Moreover, we show the strong influence of confinement on the flow topology through velocity field measurements using pulse-pair method

Functional annotation of putative QTL associated with black tea quality and drought tolerance traits

The understanding of black tea quality and percent relative water content (%RWC) traits in tea (Camellia sinensis) by a quantitative trait loci (QTL) approach can be useful in elucidation and identification of candidate genes underlying the QTL which has remained to be difficult. The objective of the study was to identify putative QTL controlling black tea quality and percent relative water traits in two tea populations and their F1 progeny. A total of 1,421 DArTseq markers derived from the linkage map identified 53 DArTseq markers to be linked to black tea quality and %RWC. All 53 DArTseq markers with unique best hits were identified in the tea genome. A total of 5,592 unigenes were assigned gene ontology (GO) terms, 56% comprised biological processes, cellular component (29%) and molecular functions (15%), respectively. A total of 84 unigenes in 15 LGs were assigned to 25 different Kyoto Encyclopedia of Genes and Genomes (KEGG) database pathways based on categories of secondary metabolite biosynthesis. The three major enzymes identified were transferases (38.9%), hydrolases (29%) and oxidoreductases (18.3%). The putative candidate proteins identified were involved in flavonoid biosynthesis, alkaloid biosynthesis, ATPase family proteins related to abiotic/biotic stress response. The functional annotation of putative QTL identified in this current study will shed more light on the proteins associated with caffeine and catechins biosynthesis and % RWC. This study may help breeders in selection of parents with desirable DArTseq markers for development of new tea cultivars with desirable traits.http://www.nature.com/sreppm2020BiochemistryGeneticsMicrobiology and Plant Patholog

Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN

Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts