Cu(In,Ga)Se2 absorber thinning and the homo-interface model: Influence of Mo back contact and 3-stage process on device characteristics

Thinning the absorber layer is one of the possibilities envisaged to further decrease the production costs of Cu(In,Ga)Se2 (CIGSe) thin films solar cell technology. In the present study, the electronic transport in submicron CIGSe-based devices has been investigated and compared to that of standard devices. It is observed that when the absorber is around 0.5 μm-thick, tunnelling enhanced interface recombination dominates, which harms cells energy conversion efficiency. It is also shown that by varying either the properties of the Mo back contact or the characteristics of 3-stage growth processing, one can shift the dominating recombination mechanism from interface to space charge region and thereby improve the cells efficiency. Discussions on these experimental facts led to the conclusions that 3-stage process implies the formation of a CIGSe/CIGSe homo-interface, whose location as well as properties rule the device operation; its influence is enhanced in submicron CIGSe based solar cells

IMPACT OF A TIO2 [NANO] COSMETICS GRADE ON THE CUTANEOUS MICROBIOTA: NANOPARTICLES BEHAVIOR IN EMULSION AND BACTERIOTOXICITY

International audienceTiO2-nanoparticles (NP) commonly used in cosmetics as physical UV-filters, are surface-modified by applying a first coating in order to quench photo-produced radicals. In addition, a second coating is sometimes added to raise their dispersibility in emulsion. Whereas European regulation mentions the obligation to demonstrate the safety of NP, very few studies took interest on their behavior in use. During formulation and storage, NP are exposed to a variety of environmental conditions which can accelerate aging and induce particles aggregation, adsorption of formula’s compounds or coatings deterioration. Consequently, a crucial question remains their safety while layered on skin and particularly their effect on the skin microflora. We will present the impact of TiO2-nanoparticles on the skin microflora in relation to their physicochemical properties in cosmetic emulsions during aging.A series of cosmetic emulsions were formulated with using conventional cosmetic ingredients, with or without Nanoparticles (NPs): one without NPs considered as blank, and two with hydrophilic and hydrophobic commercial TiO2-NPs, respectively. An emulsification process was developed and optimized to obtain a blank emulsion, physically stable, with improved NPs dispersions in emulsion. Then, emulsions were submitted to accelerate aging.Particles were extracted from the fresh/aged emulsions by original protocols allowing recovering particles with possible adsorbed compounds or cleaned surfaces.Skin bacteria growths were evaluated in emulsions or dispersions to check the toxicity of nanoparticles in use. Then, because of NP opacity, protocols were adapted to measure their effect on bacteria virulence toward skin cells.Microscopic and macroscopic characterizations revealed comparable structures and functional properties between the three fresh emulsions. Then, during aging, different behavior were registered and could be related to nanoparticle coating nature.Extracted NP from the fresh/aged formulas showed quick surface modifications in terms of chemical structures and physical properties that might be caused by adsorption or deterioration at their surfaces.For fresh emulsions, both nanoparticles did not have any impact on skin bacteria strains, S. aureus and P. fluorescens. In the case of aged emulsions, part of NPs seemed to allow the S. aureus growth, whereas others still remained with no effect on microflora. Finally, bacteria generation times and virulence toward skin cells differed depending on NPs surface treatments and exposition time.This work dealt with the impact of nanoparticles on skin microflora along cosmetic emulsion shelf-life. This new approach allows taking into account their safety when used in emulsion.First, through innovative extraction and characterization protocols, it was highlighted that chemical nature and physical properties of nanoparticle surfaces might be altered once in emulsion. These physicochemical observations were related to microbiological tests on skin representative bacteria. Effect of some of the NPs on bacteria growth and virulence evolved after aging. Finally, modification of NPs surface treatment seemed to have an effect on skin microflora

Post-transcriptional regulation in Xenopus embryos: role and targets of EDEN-BP.

International audienceEDEN (embryo deadenylation element)-dependent deadenylation is a regulatory process that was initially identified in Xenopus laevis early embryos and was subsequently shown to exist in Drosophila oocytes. Recent data showed that this regulatory process is required for somitic segmentation in Xenopus. Inactivation of EDEN-BP (EDEN-binding protein) causes severe segmentation defects, and the expression of segmentation markers in the Notch signalling pathway is disrupted. We showed that the mRNA encoding XSu(H) (Xenopus suppressor of hairless), a protein central to the Notch pathway, is regulated by EDEN-BP. Our data also indicate that other segmentation RNAs are targets for EDEN-BP. To identify new EDEN-BP targets, a microarray analysis has been undertaken

Récipients périssables en contexte de crémation : apport de la tomodensitométrie

International audienceDes contenants en matériau périssable sont fréquemment utilisés pour déposer dans une sépulture, les os d’un corps incinéré. Le phénomène concerne toutes les étapes de l’âge du Bronze et se poursuit au­delà. Cet usage est d’ailleurs une des constantes funéraires observées dans la moitié nord­-est de la France, tout au long de La Tène et de l’Antiquité. Ce travail propose un retour d’expériences centrées sur la détection et l’identification de récipients organiques utilisés en contexte crématoire. Nous avons testé l’intégration des images tomographiques dans les protocoles de fouille et d’enregistrement d’un dépôt cinéraire afin d’en évaluer les apports et les enjeux. Les deux cas d’étude présentés sont datés de l’âge du Bronze moyen et s’insèrent dans le projet ANR « Introspection du mobilier archéologique à l’ère numérique ». Ce dernier s’intéresse aux méthodes d’introspection numérique interactive en combinant la tomodensitométrie avec des technologies de visualisation 3D : réalité virtuelle, interactions tangibles et impression 3D

Identification of CUG-BP1/EDEN-BP target mRNAs in Xenopus tropicalis

The early development of many animals relies on the posttranscriptional regulations of maternally stored mRNAs. In particular, the translation of maternal mRNAs is tightly controlled during oocyte maturation and early mitotic cycles in Xenopus. The Embryonic Deadenylation ElemeNt (EDEN) and its associated protein EDEN-BP are known to trigger deadenylation and translational silencing to several mRNAs bearing an EDEN. This Xenopus RNA-binding protein is an ortholog of the human protein CUG-BP1/CELF1. Five mRNAs, encoding cell cycle regulators and a protein involved in the notch pathway, have been identified as being deadenylated by EDEN/EDEN-BP. To identify new EDEN-BP targets, we immunoprecipitated EDEN-BP/mRNA complexes from Xenopus tropicalis egg extracts. We identified 153 mRNAs as new binding targets for EDEN-BP using microarrays. Sequence analyses of the 3′ untranslated regions of the newly identified EDEN-BP targets reveal an enrichment in putative EDEN sequences. EDEN-BP binding to a subset of the targets was confirmed both in vitro and in vivo. Among the newly identified targets, Cdk1, a key player of oocyte maturation and cell cycle progression, is specifically targeted by its 3′ UTR for an EDEN-BP-dependent deadenylation after fertilization

CELF proteins regulate CFTR pre-mRNA splicing: essential role of the divergent domain of ETR-3

Cystic fibrosis is a prominent genetic disease caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Among the many disease-causing alterations are pre-mRNA splicing defects that can hamper mandatory exon inclusion. CFTR exon 9 splicing depends in part on a polymorphic UG(m)U(n) sequence at the end of intron 8, which can be bound by TDP-43, leading to partial exon 9 skipping. CELF proteins, like CUG-BP1 and ETR-3, can also bind UG repeats and regulate splicing. We show here that ETR-3, but not CUG-BP1, strongly stimulates exon 9 skipping, although both proteins bind efficiently to the same RNA motif as TDP-43 and with higher affinity. We further show that the skipping of this exon may be due to the functional antagonism between U2AF65 and ETR-3 binding onto the polymorphic U or UG stretch, respectively. Importantly, we demonstrate that the divergent domain of ETR-3 is critical for CFTR exon 9 skipping, as shown by deletion and domain-swapping experiments. We propose a model whereby several RNA-binding events account for the complex regulation of CFTR exon 9 inclusion, with strikingly distinct activities of ETR-3 and CUG-BP1, related to the structure of their divergent domain

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Synthèse et caractérisation de couches minces de Zn (O,S) pour application au sein des cellules solaires à base de Cu (In, Ga) Se2

Un des défis concernant les cellules solaires à base de Cu(In,Ga)Se2 est le remplacement de la couche tampon de CdS déposée par bain chimique (CBD) par un matériau exempt de Cd déposé sous vide. L objectif de ce travail est d évaluer le potentiel des couches minces de Zn(O,S) déposées par co-pulvérisation cathodique RF (PVD) en tant que couche tampon alternative. Les propriétés matériau de ces couches ont été tout d abord comparées à une référence (CBD)Zn(O,S) dont les conditions de dépôt ont été préalablement optimisées. Pour une composition équivalente, la technique de dépôt employée semble avoir un fort impact sur les propriétés optiques et structurales des couches. Le comportement électrique des dispositifs résultants s en trouve également affecté. Dans le cas des cellules à couche tampon (CBD)Zn(O,S), nous avons mis en évidence la nécessité de prendre en compte l ensemble du dispositif pour comprendre les phénomènes observés. Ces progrès ainsi qu une meilleure compréhension des propriétés des couches (CBD)Zn(O,S) nous ont permis de réaliser des dispositifs stables sous éclairement avec des rendements de 16 % (sans couche anti-reflet). Pour les cellules à couche tampon (PVD)Zn(O,S), l ajustement du taux de soufre a permis de contrôler l alignement de bande à la jonction absorbeur/couche tampon et de permettre l obtention de Jsc comparables à ceux des cellules avec (CBD)Zn(O,S). Bien que la structure telle quelle de la couche tampon (PVD)Zn(O,S) pour une teneur en soufre optimale ne permette pas d obtenir les Voc attendus, ces résultats ouvrent de nouvelles perspectives de recherche sur la compréhension des hétéro-interfaces dans les cellules solaires Cu(In,Ga)Se2.NANTES-BU Sciences (441092104) / SudocSudocFranceF

Synthèse de couches minces de molybdène et application au sein des cellules solaires à base de Cu (In,Ga)Se2 co-évaporé

The standard structure of thin-film solar cells based on Cu(In,Ga)Se2 (CIGSe) has polycrystalline molybdenum (Mo) layer grown on soda-lime glass as back contact. In the present study, the Mo films have been deposited by DC-magnetron sputtering; the growth parameter that has been investigated is the argon pressure during the Mo deposition. It is observed that the increase of the sputtering gas pressure yields wider inter-granular oxide, while the grains keep well crystallized Mo structure; such widening leads to hindered lateral electrical conductivity of the layers. Moreover, the inter-granular oxide area widening enhances the ability of the back contact to diffuse sodium-compounds from the glass substrate toward the co-evaporated CIGSe layer. As a consequence of this increased sodium diffusion, the distribution of group III elements (In and Ga) throughout the CIGSe layer changes from one Mo sputtering argon pressure to another; furthermore, these changes in the Mo characteristics impact the optoelectronic properties of the cells. Through the understanding of these phenomena, it is finally defined a Mo deposition process resulting in solar cells demonstrating efficiencies close to 18 %.Les cellules solaires en couches minces à base de Cu(In,Ga)Se2 (CIGSe) ont comme contact arrière une couche de molybdène (Mo) le plus souvent déposée sur un substrat de verre sodocalcique. Dans la présente étude, ces couches polycristallines de Mo ont été synthétisées par pulvérisation cathodique magnétron ; le paramètre de croissance principalement étudié ici est la pression partielle d argon durant la croissance de la couche. Il est observé que l augmentation du flux de gaz lors de la pulvérisation induit un accroissement de la largeur de l oxyde inter-granulaire alors que les grains restent des cristaux de Mo ; cet élargissement a pour conséquence une diminution de la conductivité électrique latérale des couches. Au-delà de l augmentation de la résistance carré pour une épaisseur donnée, cet élargissement induit une plus grande perméabilité des couches de Mo aux composés sodés diffusant du verre vers la couche de CIGSe co-évaporée, influençant à la fois les profiles de composition en éléments du groupe III (In et Ga) mais induisant aussi des comportements optoélectroniques différents. La compréhension de ces phénomènes a permis de définir un protocole de croissance du Mo permettant d atteindre des rendements de conversion photovoltaïques proches de 18 %.NANTES-BU Sciences (441092104) / SudocSudocFranceF