High throughput method for the development of bulk lead free piezoelectric ceramics

Combinatorial high throughput experimentation (HTE) has shortened the development cycles of several products. In thin film technologies, HTE has been successfully applied to determine the effect of various dopants on surface properties. However it is for piezoelectric actuators, where bulk properties which are dependant on a myriad of dopants are critical, that HTE concepts may present the best potential to shorten material development cycles. Research in this field is very active because the commonly used Pb(Zr,Ti)O3 (PZT) based ceramics must be replaced due to environmental concerns. Specific doping may improve the properties of the high potential candidate (KxNa1-x)NbO3 (KNN) and HTE methods may efficiently be used to screen the effect of large number of dopants on properties. In this work, a complete HTE workflow for bulk piezoelectric ceramics has been implemented, including parallel synthesis and automated characterisation. Libraries of chemically diverse oxides were produced via the mixed-oxide route and classical piezoelectric parameters such as εr, d33* and Curie temperature were automatically screened. The influence of several dopants and raw materials on the properties has also been determined and a number of new lead-free piezoelectric materials has been characterized. Best properties were obtained with the composition 0.96 [(K0.47Na0.53)0.95Li0.06](Nb0.94Ta0.06)O3 — 0.04 Sr1.85Ca.15NaNb5O15 with which a relative dielectric constant εr about 700 and a large piezoelectric coefficient d33* of 225 pm/V and a Curie temperature of 280°C was attained. This work was supported by the German Federal Ministry of Education and Research (BMBF), contract number 03X4002A.Kombinatorisches Hoch-Durchsatz Verfahren (HDV) hat die Entwicklungszeiten mehrere industrielle Produkten erfolgreich abgekürzt. In Beschichtungstechnologie ist HDV bspw. Angewendet, um die Abhängigkeit der Oberflächeeigenschaften mit den Dotierungselementen zu bestimmen. Es ist allerdings um die Abhängigkeit der Eigenschaften von bulk Bauteilen, wie piezoelektrische Systeme, die abhängig sind von einen hohen Anzahl von Dotierungselementen, dass HDV das größte Interesse hat. Arbeit in diesem Gebiet ist sehr aktuell, weil die allgemeinen bekannten Pb(Zr,Ti)O3 (PZT) Werkstoffe, aus Umwelt Gründen ersetzt werden müssen. Es ist bekannt, dass die Eigenschaften von (KxNa1-x)NbO3 (KNN), das als hoch-potenzielles Ersatz für PZT betrachtet wird, abhängig von einer großen Anzahl von Dotierungselementen sind. In dieser Arbeit wurde einen kompletten Produktionsverfahren für bulk piezoelektrische Elemente entwickelt, mit paralleler Synthese und automatischer Charakterisierung. Mehrere chemisch-diverse Oxide wurden durch den Mischoxidverfahren produziert und die klassische piezoelektrische Parametern automatisch untersucht (εr, d33* und Tc), wobei das Einfluss mehrere Dotierungselementen ebenso bestimmt wurde und neue piezoelektrische Werkstoffen entwickelt und charakterisiert wurde. Die besten Eigenschaften wurden mit 0.96 [(K0.47Na0.53)0.95Li0.06](Nb0.94Ta0.06)O3 — 0.04 Sr1.85Ca.15NaNb5O15 erreicht, mit einer relativen dielektrische Konstante εr von 700, einem piezoelektrischen Faktor d33* von 225 pm/V und einer Curie Temperatur Tc von 280°C. Dieser Arbeit würde unterstützt von dem Bundesministerium für Bildung und Forschung (BMBF), über den Projekt 03X4002A

Hochdurchsatzmethode für die Entwicklung bleifreier Piezokeramik

Combinatorial high throughput experimentation (HTE) has shortened the development cycles of several products. In thin film technologies, HTE has been successfully applied to determine the effect of various dopants on surface properties. However it is for piezoelectric actuators, where bulk properties which are dependant on a myriad of dopants are critical, that HTE concepts may present the best potential to shorten material development cycles. Research in this field is very active because the commonly used Pb(Zr,Ti)O3 (PZT) based ceramics must be replaced due to environmental concerns. Specific doping may improve the properties of the high potential candidate (KxNa1-x)NbO3 (KNN) and HTE methods may efficiently be used to screen the effect of large number of dopants on properties. In this work, a complete HTE workflow for bulk piezoelectric ceramics has been implemented, including parallel synthesis and automated characterisation. Libraries of chemically diverse oxides were produced via the mixed-oxide route and classical piezoelectric parameters such as εr, d33* and Curie temperature were automatically screened. The influence of several dopants and raw materials on the properties has also been determined and a number of new lead-free piezoelectric materials has been characterized. Best properties were obtained with the composition 0.96 [(K0.47Na0.53)0.95Li0.06](Nb0.94Ta0.06)O3 — 0.04 Sr1.85Ca.15NaNb5O15 with which a relative dielectric constant εr about 700 and a large piezoelectric coefficient d33* of 225 pm/V and a Curie temperature of 280°C was attained. This work was supported by the German Federal Ministry of Education and Research (BMBF), contract number 03X4002A.Kombinatorisches Hoch-Durchsatz Verfahren (HDV) hat die Entwicklungszeiten mehrere industrielle Produkten erfolgreich abgekürzt. In Beschichtungstechnologie ist HDV bspw. Angewendet, um die Abhängigkeit der Oberflächeeigenschaften mit den Dotierungselementen zu bestimmen. Es ist allerdings um die Abhängigkeit der Eigenschaften von bulk Bauteilen, wie piezoelektrische Systeme, die abhängig sind von einen hohen Anzahl von Dotierungselementen, dass HDV das größte Interesse hat. Arbeit in diesem Gebiet ist sehr aktuell, weil die allgemeinen bekannten Pb(Zr,Ti)O3 (PZT) Werkstoffe, aus Umwelt Gründen ersetzt werden müssen. Es ist bekannt, dass die Eigenschaften von (KxNa1-x)NbO3 (KNN), das als hoch-potenzielles Ersatz für PZT betrachtet wird, abhängig von einer großen Anzahl von Dotierungselementen sind. In dieser Arbeit wurde einen kompletten Produktionsverfahren für bulk piezoelektrische Elemente entwickelt, mit paralleler Synthese und automatischer Charakterisierung. Mehrere chemisch-diverse Oxide wurden durch den Mischoxidverfahren produziert und die klassische piezoelektrische Parametern automatisch untersucht (εr, d33* und Tc), wobei das Einfluss mehrere Dotierungselementen ebenso bestimmt wurde und neue piezoelektrische Werkstoffen entwickelt und charakterisiert wurde. Die besten Eigenschaften wurden mit 0.96 [(K0.47Na0.53)0.95Li0.06](Nb0.94Ta0.06)O3 — 0.04 Sr1.85Ca.15NaNb5O15 erreicht, mit einer relativen dielektrische Konstante εr von 700, einem piezoelektrischen Faktor d33* von 225 pm/V und einer Curie Temperatur Tc von 280°C. Dieser Arbeit würde unterstützt von dem Bundesministerium für Bildung und Forschung (BMBF), über den Projekt 03X4002A

Les 4000 logements de La Courneuve : réalités et imaginaires cinématographiques

Le film Deux ou trois choses que je sais d’elle de Jean-Luc Godard (1967) constitue une étape importante dans la représentation de la banlieue parisienne. Pour la première fois, à partir d’une enquête journalistique, un cinéaste filme de l’intérieur un grand ensemble, en l’occurrence les 4 000 de La Courneuve. Aurélie Cardin montre comment Godard réalise une fiction sur le mal-vivre et sur la déshumanisation des rapports sociaux dans un contexte de réorganisation de la région parisienne à travers les schémas d’aménagement et la construction de « grands ensembles » reliés entre eux par la seule logique d’une circulation autoroutière centrée sur Paris

Introduction to the versatility of biomimetic membranes to characterize modulators of Aβ1-42 fibrillization with potential interest in Alzheimer's disease treatment

International audienceAlzheimer’s Alzheimer’s Alzheimer’s Alzheimer’s Alzheimer’s disease disease(AD) (AD) is the most widespread widespread widespread form of senile dementia dementia worldwide worldwide and representsrepresents represents the leading leading leading socioeconomic socioeconomic socioeconomicproblem problem in healthcare healthcare healthcarehealthcare .The onset onsetonsetand the progression progression progression of this thisneurodegenerative neurodegenerative disease disease is associated associated associated with with the aggregation aggregation of the amyloid amyloid -β peptide (Aβ) through afibrillization fibrillization process. Hence, an attractive attractive attractive attractive therapeutictherapeutic therapeutic strategy strategy against against this thisdisorderdisorder disorder is the development development developmentof molecules moleculesmolecules able able to interfere interfereinterfere interfere at specific specificsteps steps of thisthis fibrillization fibrillization fibrillization pathway pathway 1,i.e.able able to inhibit inhibit the formation of the soluble toxic toxicoligomeric oligomeric oligomericAβ aggregates. To identify identify such suchpromisingpromising therapeutic therapeutic therapeutic molecules, experimental experimental experimental experimentalexperimental methods methodsmethods are required in vitro vitro to precisely precisely follow and characterize characterize characterize thethe state state (monomer/oligomers (monomer/oligomers(monomer/oligomers /fibrils) /fibrils) /fibrils) and the conformation conformation conformation of Aβ peptide peptide duringduring its fibrillization fibrillization fibrillizationfibrillization process process .In the same time,time, these methods methods methodsmust mustbe simple enough to remain compatible compatiblecompatible compatible with the High High Throughput Throughput Screening Screening(HTS) of new compounds compounds with with potential potential interest interest in AD treatment treatment. In the present study, study, study,we propose propose to combine combine combineexperimental experimental experimental methods methodsto allow amultiparameter multiparameter multiparameter characterization characterization characterization characterization of potential potential modulators of Aβ 1-42 fibrillization fibrillization fibrillization. These Thesekinetickinetic kinetic studies studiesare carried carried out in presence presence of liposomes liposomes as biomimetic biomimetic biomimetic biomimeticneuronal neuronal neuronal membranes membranesmembranes membranes .Indeed, Indeed, it hashas been establishedestablished established established that lipidslipids lipids lipidsof thethe neuronal neuronalmembrane membrane are an important important factor factor in the cascade cascade of events that leads to the formation formation of the amyloid amyloid fibers

A biomimetic multiparametric assay to characterise anti-amyloid drugs

International audienceAlzheimer's disease (AD) is the most widespread form of senile dementia worldwide and represents a leading socioeconomic problem in healthcare. Although it is widely debated, the aggregation of the amyloid β peptide (Aβ) is linked to the onset and progression of this neurodegenerative disease. Molecules capable of interfering with specific steps in the fibrillation process remain of pharmacological interest. To identify such compounds, we have set up a small molecule screening process combining multiple experimental methods (UV and florescence spectrometry, ITC, and ATR-FTIR) to identify and characterise potential modulators of Aβ 1-42 fibrillation through the description of the biochemical interactions (molecule-membrane Aβ peptide). Three known modulators, namely bexarotene, Chicago sky blue and indomethacin, have been evaluated through this process, and their modulation mechanism in the presence of a biomembrane has been described. Such a well-adapted physico-chemical approach to drug discovery proves to be an undeniable asset for the rapid characterisation of compounds of therapeutic interest for Alzheimer's disease. This strategy could be adapted and transposed to search for modulators of other amyloids such as tau protein

Non-canonical ATM/MRN activities temporally define the senescence secretory program.

Senescent cells display senescence-associated (SA) phenotypic programs such as stable proliferation arrest (SAPA) and a secretory phenotype (SASP). Senescence-inducing persistent DNA double-strand breaks (pDSBs) cause an immediate DNA damage response (DDR) and SAPA, but the SASP requires days to develop. Here, we show that following the immediate canonical DDR, a delayed chromatin accumulation of the ATM and MRN complexes coincides with the expression of SASP factors. Importantly, histone deacetylase inhibitors (HDACi) trigger SAPA and SASP in the absence of DNA damage. However, HDACi-induced SASP also requires ATM/MRN activities and causes their accumulation on chromatin, revealing a DNA damage-independent, non-canonical DDR activity that underlies SASP maturation. This non-canonical DDR is required for the recruitment of the transcription factor NF-κB on chromatin but not for its nuclear translocation. Non-canonical DDR further does not require ATM kinase activity, suggesting structural ATM functions. We propose that delayed chromatin recruitment of SASP modulators is the result of non-canonical DDR signaling that ensures SASP activation only in the context of senescence and not in response to transient DNA damage-induced proliferation arrest