Témoignages d’anciens résidents de la Maison des étudiants des États d’Afrique de l’Ouest

Témoignage d’Issa Sory, reportage Les passagers de la case Ponia réalisé par les auteurs pour leur site multimédia L’Oeil acoustique « Je suis burkinabé, je suis étudiant à Paris-I et président de l’Association des étudiants burkinabés en France, vieille association qui date de 1950 et qui a participé avec d’autres associations d’étudiants de pays africains à la création de la Fédération des étudiants d’Afrique noire en France (FEANF). Ce bâtiment a beaucoup apporté à la jeunesse africaine. L..

Rapid on-site detection of harmful algal blooms: real-time cyanobacteria identification using Oxford Nanopore sequencing

With the increasing occurrence and severity of cyanobacterial harmful algal blooms (cHAB) at the global scale, there is an urgent need for rapid, accurate, accessible, and cost-effective detection tools. Here, we detail the RosHAB workflow, an innovative, in-the-field applicable genomics approach for real-time, early detection of cHAB outbreaks. We present how the proposed workflow offers consistent taxonomic identification of water samples in comparison to traditional microscopic analyses in a few hours and discuss how the generated data can be used to deepen our understanding on cyanobacteria ecology and forecast HABs events. In parallel, processed water samples will be used to iteratively build the International cyanobacterial toxin database (ICYATOX; http://icyatox.ibis.ulaval.ca) containing the analysis of novel cyanobacterial genomes, including phenomics and genomics metadata. Ultimately, RosHAB will (1) improve the accuracy of on-site rapid diagnostics, (2) standardize genomic procedures in the field, (3) facilitate these genomics procedures for non-scientific personnel, and (4) identify prognostic markers for evidence-based decisions in HABs surveillance

Optical lithography patterning of SiO2 layers for interface passivation of thin film solar cells

Ultrathin Cu(In,Ga)Se2 solar cells are a promising way to reduce costs and to increase the electrical performance of thin film solar cells. In this work, we develop an optical lithography process that can produce sub-micrometer contacts in a SiO2 passivation layer at the CIGS rear contact. Furthermore, an optimization of the patterning dimensions reveals constrains over the features sizes. High passivation areas of the rear contact are needed to passivate the CIGS interface so that high performing solar cells can be obtained. However, these dimensions should not be achieved by using long distances between the contacts as they lead to poor electrical performance due to poor carrier extraction. This study expands the choice of passivation materials already known for ultrathin solar cells and its fabrication techniques.publishe

The impact of IL-10 dynamic modulation on host immune response against visceral leishmaniasis

Leishmaniasis is a vector-borne disease caused by protozoan parasites from the genus Leishmania. The most severe form of disease is visceral leishmaniasis (VL), which is fatal if left untreated. It has been demonstrated that interleukin (IL)-10, is associated with disease progression and susceptibility. In this work, we took advantage of a transgenic mouse model that expresses high levels of IL-10 upon zinc sulfate administration (pMT-10). We addressed the role of IL-10 during the initial stages of L. donovani infection by analyzing the parasite burden in the spleen and liver of the infected pMT-10 and WT mice as well as the histopathological alterations upon IL-10 induction. Furthermore, the profile of cytokines expressed by T cells was assessed. Our results demonstrate that an increase in IL-10 production has an impact early but not later after infection. This specific temporal role for IL-10-mediated susceptibility to VL is of interest.Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000013) and the Fundação para a Ciência e Tecnologia (FCT) (contracts SFRH/BD/120127/2016 to IM, PD/BDE/127830/2016 to CF, SFRH/BD/120371/2016 to AMB, IF/01147/2013 to RDO, IF/01390/2014 to ET, IF/00735/2014 to AC, SFRH/BPD/96176/2013 to CC and IF/00021/2014 to RS), and Infect-Era (project INLEISH). JE also thanks the Canada Research Chair program for financial assistanceinfo:eu-repo/semantics/publishedVersio

Incidence, predictive factors and haemodynamic consequences of acute stent recoil following transcatheter aortic valve implantation with a balloon-expandable valve

Aims: The elastic behaviour (acute recoil) of a valve prosthesis stent following transcatheter aortic valve implantation (TAVI) is unknown. This study sought to determine the occurrence, severity, predictive factors and haemodynamic consequences of acute recoil following TAVI. Methods and results : A prospective angiographic analysis of the stent frame dimensions in 111 consecutive patients who underwent TAVI with a balloon-expandable valve (36 Edwards SAPIEN; 75 SAPIEN XT) was performed. Acute recoil was defined as the difference between minimal lumen diameter (MLD) at full balloon expansion and immediately after balloon deflation. MLD during balloon inflation was significantly larger than MLD after balloon deflation (23.40±2.31 mm vs. 22.29±2.21 mm, p<0.001), which represented an absolute and percent decrease in stent dimension of 1.10±0.40 mm and 4.70±1.76%, respectively. In the multivariate analysis, the predictors of larger recoil were a higher prosthesis/annulus ratio (r²=0.0624, p=0.015) and the SAPIEN XT prosthesis (r²=0.1276, p=0.001). No significant changes in haemodynamic performance were observed at discharge and follow-up in patients with larger recoil. Conclusions : TAVI with a balloon-expandable valve was systematically associated with a certain degree of valve stent recoil after balloon deflation. A higher degree of valve oversizing and the SAPIEN XT prosthesis predicted a larger degree of stent recoil

Cu(In,Ga)Se2 based ultrathin solar cells: the pathway from lab rigid to large scale flexible technology

For the first time, the incorporation of interface passivation structures in ultrathin Cu(In,Ga)Se2 (CIGS) based solar cells is shown in a flexible lightweight stainless-steel substrate. The fabrication was based on an industry scalable lithography technique - nanoimprint lithography (NIL) - for a 15x15 cm2 dielectric layer patterning, needed to reduce optoelectronic losses at the rear interface. The nanopatterning schemes are usually developed by lithographic techniques or by processes with limited scalability and reproducibility (nanoparticle lift-off, spin-coating, etc). However, in this work the dielectric layer is patterned using NIL, a low cost, large area, high resolution, and high throughput technique. To assess the NIL performance, devices with a NIL nanopatterned dielectric layer are benchmarked against electron-beam lithography (EBL) patterning, using rigid substrates. Up to now, EBL is considered the most reliable technique for patterning laboratory samples. The device patterned by NIL shows similar light to power conversion efficiency average values compared to the EBL patterned device - 12.6 % vs 12.3 %, respectively - highlighting the NIL potential for application in the solar cell sector. Moreover, the impact of the lithographic processes, such as different etch by-products, in the rigid solar cells’ figures of merit were evaluated from an elemental point of view via X-ray Photoelectron Spectroscopy and electrically through a Solar Cell Capacitance Simulator (SCAPS) fitting procedure. After an optimised NIL process, the device on stainless-steel achieved an average power conversion efficiency value of 11.7 % - a slightly lower value than the one obtained for the rigid approach, due to additional challenges raised by processing and handling steel substrates, even though scanning transmission electron microscopy did not show any clear evidence of impurity diffusion towards the absorber. Notwithstanding, time-resolved photoluminescence results strongly suggested the presence of additional non-radiative recombination mechanisms in the stainless-steel absorber, which were not detected in the rigid solar cells, and are compatible with elemental diffusion from the substrate. Nevertheless, bending tests on the stainless-steel device demonstrated the mechanical stability of the CIGS-based device up to 500 bending cycles.This work was funded in part by the Fundação para a Ciência e a Tecnologia (FCT) under Grants 2020.04564.BD, IF/00133/2015, PD/BD/142780/2018, SFRH/BD/146776/2019, UIDB/04564/2020 and UIDP/04564/2020, 2020.07073.BD, as well as through the projects NovaCell (PTDC/CTMCTM/28075/2017), CASOLEM (028917) “Correlated Analysis of Inorganic Solar Cells in and outside an Electron Microscope”, and InovSolarCells (PTDC/FISMAC/29696/2017) co-funded by FCT and the ERDF through COMPETE2020. And by the European Union's Horizon 2020 research and innovation 15 programme under the grants agreements N°. 720887 (ARCIGS-M project) and grand agreement N°.715027 (Uniting PV). The Special Research Fund (BOF) of Hasselt University is also acknowledged. P. Salomé and P. A. Fernandes would like to acknowledge FCT for the support of the project FCT UIDB/04730/2020. This work was developed within the scope of the project i3N, UIDB/50025/2020 & UIDP/50025/2020, financed by national funds through the FCT/MEC. The authors also acknowledge the support of Carlos Calaza in the fabrication for the 200 mm Si point contact stamp.info:eu-repo/semantics/publishedVersio

Conferring a template-dependent polymerase activity to terminal deoxynucleotidyltransferase by mutations in the Loop1 region

Terminal deoxynucleotidyltransferase (Tdt) and DNA polymerase μ (pol μ) are two eukaryotic highly similar proteins involved in DNA processing and repair. Despite their high sequence identity, they differ widely in their activity: pol μ has a templated polymerase activity, whereas Tdt has a non-templated one. Loop1, first described when the Tdt structure was solved, has been invoked as the major structural determinant of this difference. Here we describe attempts to transform Tdt into pol μ with the minimal number of mutations in and around Loop1. First we describe the effect of mutations on six different positions chosen to destabilize Tdt Loop1 structure, either by alanine substitution or by deletion; they result at most in a reduction of Tdt activity, but adding Co++ restores most of this Tdt activity. However, a deletion of the entire Loop1 as in pol λ does confer a limited template-dependent polymerase behavior to Tdt while a chimera bearing an extended pol μ Loop1 reproduces pol μ behavior. Finally, 16 additional substitutions are reported, targeted at the two so-called ‘sequence determinant’ regions located just after Loop1 or underneath. Among them, the single-point mutant F401A displays a sequence-specific replicative polymerase phenotype that is stable upon Co++ addition. These results are discussed in light of the available crystal structures

Mo thio and oxo-thio molecular complexes film as self-healing catalyst for photocatalytic hydrogen evolution on 2D materials

2D semiconducting nanosheets of Transition Metal Dichalcogenides are attractive materials for solar energy conversion because of their unique absorption properties. Here, we show that Mo thio- and oxo-thio-complexes anchored on 2D p-WSe2 nanosheets considerably boost water splitting under visible light irradiation with photocurrent density up to 2.0 mA cm−2 at -0.2 V/NHE. Besides developing high electro-catalytic activity, the Mo-complexes film is also shown to be capable of healing surface defects. We propose that the observed healing of surface defects arises from the strong adsorption on point defects of the 2D WSe2 substrate of Mo complexes such as (MoS4)2-, (MoOS3)2-, (Mo2S6O2)2- as supported by DFT calculations. In addition, the thio-, oxo-thio Mo complexes films are shown to enhance charge carrier separation and migration favouring the hydrogen evolution reaction, putting forward the use of thio-, oxo-thio-Mo complexes as a multicomponent passivation layer exhibiting multiple properties