Potential of geothermal systems in Picardy

Geothermal systems are not only about electrical plants or urban heating networks, but also concerned with geothermal energy assisted with a heat pump. In the former region of Picardy (North of France), 97% of the territory is suitable for very low temperature geothermal power. The French Agency for the Environment and Energy Management and the Picardy Region decided in 2016 to finance a facilitator to encourage geothermal use. To carry out this aim, it is important to consider the geothermal context in Picardy, its regulation and the potential, but also the local tools available, such as an inventory of geothermal installations or training sessions for architects. The objective is to help increase the number of geothermal projects in Picardy

The Influence of Magnetic Domain Walls on Longitudinal and Transverse Magnetoresistance in Tensile Strained (Ga,Mn)As Epilayers

We present a theoretical analysis of recent experimental measurements of magnetoresistance in (Ga,Mn)As epilayers with perpendicular magnetic anisotropy. The model reproduces the field-antisymmetric anomalies observed in the longitudinal magnetoresistance in the planar geometry (magnetic field in the epilayer plane and parallel to the current density), as well as the unusual shape of the accompanying transverse magnetoresistance. The magnetoresistance characteristics are attributed to circulating currents created by the presence of magnetic domain walls

Field-Driven Domain-Wall Dynamics in GaMnAs Films with Perpendicular Anisotropy

We combine magneto-optical imaging and a magnetic field pulse technique to study domain wall dynamics in a ferromagnetic (Ga,Mn)As layer with perpendicular easy axis. Contrary to ultrathin metallic layers, the depinning field is found to be smaller than the Walker field, thereby allowing for the observation of the steady and precessional flow regimes. The domain wall width and damping parameters are determined self-consistently. The damping, 30 times larger than the one deduced from ferromagnetic resonance, is shown to essentially originate from the non-conservation of the magnetization modulus. An unpredicted damping resonance and a dissipation regime associated with the existence of horizontal Bloch lines are also revealed

Determination of the micromagnetic parameters in (Ga,Mn)As using domain theory

The magnetic domain structure and magnetic properties of a ferromagnetic (Ga,Mn)As epilayer with perpendicular magnetic easy-axis are investigated. We show that, despite strong hysteresis, domain theory at thermodynamical equilibrium can be used to determine the micromagnetic parameters. Combining magneto-optical Kerr microscopy, magnetometry and ferromagnetic resonance measurements, we obtain the characteristic parameter for magnetic domains $\lambda_c$, the domain wall width and specific energy, and the spin stiffness constant as a function of temperature. The nucleation barrier for magnetization reversal and the Walker breakdown velocity for field-driven domain wall propagation are also estimated

Domain Wall Resistance in Perpendicular (Ga,Mn)As: dependence on pinning

We have investigated the domain wall resistance for two types of domain walls in a (Ga,Mn)As Hall bar with perpendicular magnetization. A sizeable positive intrinsic DWR is inferred for domain walls that are pinned at an etching step, which is quite consistent with earlier observations. However, much lower intrinsic domain wall resistance is obtained when domain walls are formed by pinning lines in unetched material. This indicates that the spin transport across a domain wall is strongly influenced by the nature of the pinning.Comment: 9 pages, 3 figure

Reversal of diastereoselectivity in the synthesis of Peptidomimetic 3‑Carboxamide-1,4-benzodiazepin-5-ones

Enantiopure 3-carboxamide-1,4-benzodiazepin-5-ones were synthesized via the Ugi reaction followed by the Staudinger/aza-Wittig or reduction reactions in only two steps. A complete reversal of diastereoselectivity was achieved depending on the cyclization methodology employed. The different orientation of the C3 substituent in our 3-substituted 1,4-benzodiazepin-5-ones with respect to the most studied 1,4-benzodiazepin-2-ones makes them complementary in the development of new drugs because the primary source of binding selectivity of 1,4-benzodiazepines is the selective recognition of ligand conformations by the receptor.Ministerio de Economía y Competitividad, Spain (Project CTQ2012-31611), Junta de Castilla y León, Consejería de Educación y Cultura y Fondo Social Europeo (Project BU246A12-1) and the European Commission, Seventh Framework Programme (Project SNIFFER FP7-SEC-2012-312411)

Integrated Ugi-Based Assembly of Functionally, Skeletally, and Stereochemically Diverse 1,4-Benzodiazepin-2-ones

A practical, integrated and versatile U-4CR-based assembly of 1,4-benzodiazepin-2-ones exhibiting functionally, skeletally, and stereochemically diverse substitution patterns is described. By virtue of its convergence, atom economy, and bond-forming efficiency, the methodology documented herein exemplifies the reconciliation of structural complexity and experimental simplicity in the context of medicinal chemistry projects.This work was financially supported by the Galician Government (Spain), Projects: 09CSA016234PR and GPC-2014-PG037. J.A. thanks FUNDAYACUCHO (Venezuela) for a predoctoral grant and Deputación da Coruña (Spain) for a postdoctoral research grant. A.N.-V. thanks the Spanish government for a Ramón y Cajal research contract

Conception, synthèse et évaluation biologique d'inhibiteurs de la dimérisation de STAT3 à activité anti-tumorale potentielle

La protéine STAT3 est un facteur de transcription qui régule sous forme dimère les événements majeurs de la tumorigenèse. STAT3 est suractivée dans de nombreux cancers et constitue une cible antitumorale attractive. Notre travail a consisté dans un premier temps, à valider l'inhibition de la dimérisation comme stratégie anti-tumorale, à l'aide d'un puissant ligand phosphopeptidique du domaine SH2 de STAT3. Ce phosphopeptide inhibe in vitro la dimérisation de STAT3 avec une IC50 de l'ordre du micromolaire. Une fois vectorisé, il inhibe l'activité oncogénique de STAT3 dans une lignée tumorale STAT3-dépendante (NIH 3T3/v-Src). En parallèle, un nouvel inhibiteur peptidique non-phosphorylé a été identifié. Ces deux peptides ont également démontré des effets apoptotiques très significatifs sur des cellules HT-29 (cancer du colon). La seconde approche, basée sur des données structurales, a eu pour objectif la conception d'inhibiteurs phosphopeptidiques, peptidomimétiques et non-peptidiques de la dimérisation. Les phosphopeptides ont démontré des effets inhibiteurs modestes. Les peptidomimétiques, incorporant des analogues non-hydrolysables de la phosphotyrosine, ont conduit au premier peptidomimétique non-phosphore actif sur la dimérisation. Les premiers composés non-peptidiques dérivés de benzodiazépines se sont révélés inactifs sur la dimérisation, mais ont démontré des effets antiprolifératifs sur cellules HeLa, A2058 et NIH 3T3/v-src. Enfin, des dérivés de chalcone ont été préparés, et ont conduit à des agents présentant des effets inhibiteurs de l'ordre de quelques centaines de micromolaire sur la dimérisation de STAT3.STATS is a latent cytoplasmic transcription factor that regulates as a dimer the main processes of tumorigenesis. STATS is overactivated in numerous tumors and constitutes as such a promising cancer target. Our work has firstly consisted in validating the inhibition of STATS dimerization as an anti-tumoral approach. A powerful phosphopeptidic ligand targeted to the STATS-SH2 domain was found to inhibit STATS dimerization with an activity in the low micromolar range and was capable of inhibiting STATS oncogenic activity in a tumoral STATS-dependent cell line (NIH 3T3/v-Src), once vectorized. Some of it pharmacological effects were also characterized. In the same time, a novel non-phosphorylated peptide inhibitor of STATS oncogenic activity was also identified. Both peptides were next evaluated on a colon cancer cell line and demonstrated significant apoptotic effects. The second approach has consisted in the conception of different kind of inhibitors (phosphopeptidic, peptidomimetic and non-peptidic compounds). Phosphopeptides demonstrated modest activities on STATS dimerization, whereas conception of peptidomimetics incorporating non-hydrolyzable phosphotyrosine analogs led to the identification of the first non-phosphorous peptidomimetic active on STATS dimerization. The first non-peptidic compounds, based on the 1,4-benzodiazepine scaffold, were found inactive on STATS dimerization but displayed antiproliferative effects on HeLa, A2058 and NIH 3T3/v-src tumor cells. Chalcone derivatives were finally prepared. Modifications done on the reference compound led to molecules displaying greatly enhanced affinities, around hundred micromolars on STATS dimerization.PARIS-BIUP (751062107) / SudocSudocFranceF