Diazonium-based anchoring of PEDOT on Pt/Ir electrodes via diazonium chemistry

Conducting polymers, specifically poly (3,4-ethylenedioxythiophene) (PEDOT), have recently been coated onto Pt/Ir electrodes intended for neural applications, such as deep brain stimulation (DBS). This modification reduces impedance, increases biocompatibility, and increases electrochemically active surface area. However, direct electropolymerization of PEDOT onto a metallic surface results in physically adsorbed films that suffer from poor adhesion, precluding their use in applications requiring in vivo functionality (i.e. DBS treatment). In this work, we propose a new attachment strategy, whereby PEDOT is covalently attached to an electrode surface through an intermediate phenylthiophene layer, deposited by electrochemical reduction of a diazonium salt. Our electrodes retain their electrochemical performance after more than 1000 redox cycles, whereas physically adsorbed films begin to delaminate after only 40 cycles. Additionally, covalently attached PEDOT maintained strong adhesion even after 10 minutes of ultrasonication (vs. 10 s for physically adsorbed films), confirming its suitability for long-term implantation in the brain. The simple two-step covalent attachment strategy proposed here is particularly useful for neural applications and could also be adapted to introduce other functionalities on the conducting surface

The Effects of Ash and Black Carbon (Biochar) on Germination of Different Tree Species

Forest fires generate large amounts of ash and biochar, or black carbon (BC), that cover the soil surface, interacting with the soil’s constituents and its seedbank. This study concerns reproductive ecology assessments supported by molecular characterisation to improve our understanding of the effects of fire and fire residues on the germination behaviour of 12 arboreal species with a wide geographic distribution. For this purpose, we analysed the effects of three ash and one BC concentration on the germination of Acacia dealbata Link, A. longifolia (Andrews) Willd., A. mearnsii De Wild., A. melanoxylon R. Br., Pinus nigra Arnold, P. pinaster Aiton, P. radiata D. Don, P. sylvestris L., Quercus ilex L., Q. pyrenaica Willd., Q. robur L., and Q. rubra L. Each tree species was exposed to ash and BC created from its foliage or twigs (except for Q. rubra, which was exposed to ash and BC of Ulex europaeus L.). We monitored germination percentage, the T50 parameter, and tracked the development of germination over time (up to 1 yr). The BC of A. dealbata, P. pinaster, and Q. robur was analysed by pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS) to assess the molecular composition. In six species, ash inhibited the germination, while in another five species, germination was not affected by ash or by BC. In Q. rubra, ash and BC stimulated its germination. This stimulating effect of the BC on Q. rubra is likely to be related to the chemical composition of the ash and BC obtained from Ulex feedstock. The BC of U. europaeus has a very different molecular composition than the other BC samples analysed, which, together with other factors, probably allowed for its germination stimulating effects.This study was carried out within the Project 10MDS200007PR, financed by the Xunta de Galicia; the Project AGL2013-48189-C2-2-R, financed by the Ministerio de Economía y Competitividad, Spain; and FEDERS

Second generation tyrosine kinase inhibitors prevent disease progression in high-risk (high CIP2A) chronic myeloid leukaemia patients.

High cancerous inhibitor of PP2A (CIP2A) protein levels at diagnosis of chronic myeloid leukaemia (CML) are predictive of disease progression in imatinib-treated patients. It is not known whether this is true in patients treated with second generation tyrosine kinase inhibitors (2G TKI) from diagnosis, and whether 2G TKIs modulate the CIP2A pathway. Here, we show that patients with high diagnostic CIP2A levels who receive a 2G TKI do not progress, unlike those treated with imatinib (P=<0.0001). 2G TKIs induce more potent suppression of CIP2A and c-Myc than imatinib. The transcription factor E2F1 is elevated in high CIP2A patients and following 1 month of in vivo treatment 2G TKIs suppress E2F1 and reduce CIP2A; these effects are not seen with imatinib. Silencing of CIP2A, c-Myc or E2F1 in K562 cells or CML CD34+ cells reactivates PP2A leading to BCR-ABL suppression. CIP2A increases proliferation and this is only reduced by 2G TKIs. Patients with high CIP2A levels should be offered 2G TKI treatment in preference to imatinib. 2G TKIs disrupt the CIP2A/c-Myc/E2F1 positive feedback loop, leading to lower disease progression risk. The data supports the view that CIP2A inhibits PP2Ac, stabilising E2F1, creating a CIP2A/c-Myc/E2F1 positive feedback loop, which imatinib cannot overcome

Mécanique des roches et évacuation des déchets radioactifs en formations géologiques

L'enfouissement en formation géologique profonde des déchets hautement radioactifs est actuellement la méthode la plus prometteuse pour isoler ces déchets de l'homme et de son environnement.La Commission des Communautés Européennes poursuit un programme de recherche et développement visant, entre autres, à évaluer la sûreté de cette approche. L'article présente quelques résultats particulièrement intéressants acquis dans le cadre de ce programme, concernant (a) la détermination et la modélisation du comportement mécanique des formations rocheuses, et (b) l'évolution à long terme de ces formations

Une comparaison préliminaire de modèles rhéologiques pour l’argile plastique : l’exercice communautaire INTERCLAY (phase pilote-1989)

On a comparé des modèles décrivant le comportement différé de l'argile plastique de Boom (Belgique), selon deux approches : (a) fluage, et (b) dissipation de pression interstitielle. Dans une première phase pilote, trois équipes ont résolu, indépendamment, deux problèmes simplifiés : (1) l'excavation d'un tunnel profond avec pose d'un revêtement rigide et perméable ; (2) un essai de fluage in situ au dilatomètre. Les données provenaient d'essais de laboratoire sur le même matériau. On présente ici les premiers enseignements tirés de cette comparaison.Ces travaux ont été réalisés dans le cadre du 3e programme communautaire de R&D sur « la gestion et le stockage des déchets radioactifs »

La deuxième phase du projet communautaire COSA (intercomparaison de codes de calcul géomécaniques pour le sel)

La deuxième phase du projet communautaire COSA (intercomparaison de codes de calcul géomécaniques pour le sel), composante du programme communautaire « Gestion et stockage des déchets radioactifs », s'est achevée en janvier 1989. Au total, treize organismes spécialisés (dont le secrétariat technique, WS ATKINS E-S, GB) ont participé à l'exercice, qui a évalué les capacités actuelles de modélisateurs, en vue de la prévision numérique de situations thermomécaniques réelles et raisonnablement complexes. Il est ainsi apparu que, bien plus que les outils numériques (codes sur ordinateur) eux-mêmes, les concepts rhéologiques pour le sel devront être l'objet de perfectionnements