scispace - formally typeset
Search or ask a question
Institution

École normale supérieure de Cachan

EducationCachan, Île-de-France, France
About: École normale supérieure de Cachan is a education organization based out in Cachan, Île-de-France, France. It is known for research contribution in the topics: Decidability & Finite element method. The organization has 2717 authors who have published 5585 publications receiving 175925 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: A large increase of the second-order NLO activity after UV irradiation and subsequent formation of the ring-closed isomers is revealed, reflecting the delocalization of the π-electron system and the formation of strong push-pull chromophores in the closed forms.
Abstract: A series of dithienylethene (DTE)-containing 2,2'-bipyridine ligands and their zinc(II) diacetate, zinc(II) dichloro, rhenium(I) tricarbonyl bromo, and ruthenium(II) bis(bipyridine) complexes have been designed and synthesized, and their photochromic, photophysical, and quadratic nonlinear optical properties have been studied. Upon UV irradiation at 350 nm, the ligands and complexes undergo ring closure of the DTE units, with a good to excellent photocyclization yield. In the case of the Re(I) and Ru(II) complexes, the photocyclization of the DTE units can also be triggered using visible light, upon excitation into the metal-to-ligand charge-transfer (MLCT) bands at 400 and 490 nm, respectively. Molecular quadratic nonlinear optical (NLO) responses of the complexes have been determined by using either the electrical field induced second harmonic generation (EFISH) or harmonic light scattering (HLS) technique at 1910 nm. These studies reveal a large increase of the second-order NLO activity after UV irradiation and subsequent formation of the ring-closed isomers. This efficient enhancement clearly reflects the delocalization of the π-electron system and the formation of strong push-pull chromophores in the closed forms. The combination of the photochromic DTE-based bipyridine ligand with luminescent Re(I) and Ru(II) fragments also allows the photoregulation of the emission, leading to an efficient quenching of the ligand-based 77 K luminescence and demonstrating that the photocontrol of two optical properties, linear and nonlinear, could be achieved by using the same photochromic ligand.

62 citations

Journal ArticleDOI
TL;DR: In this paper, the authors consider the stability of shape-dependent energy functional shapes and prove weak-coercivity of the second derivative uniformly in a "strong" neighborhood of the equilibrium shape.
Abstract: We discuss the stability of "critical" or "equilibrium" shapes of a shape-dependent energy functional. We analyze a problem arising when looking at the positivity of the second derivative in order to prove that a critical shape is an optimal shape. Indeed, often when positivity -or coercivity- holds, it does for a weaker norm than the norm for which the functional is twice differentiable and local optimality cannot be a priori deduced. We solve this problem for a particular but significant example. We prove "weak-coercivity" of the second derivative uniformly in a "strong" neighborhood of the equilibrium shape.

62 citations

Journal ArticleDOI
TL;DR: The study reveals the interplay between various forms of the viral DNA genome, the distribution of which can be affected by mutations and by inhibitors of HIV-1 viral proteins.
Abstract: HIV-1 DNA is found both integrated in the host chromosome and unintegrated in various forms: linear (DNAL) or circular (1-LTRc, 2-LTRc or products of auto-integration). Here, based on pre-established strategies, we extended and characterized in terms of sensitivity two methodologies for quantifying 1-LTRc and DNAL, respectively, the latter being able to discriminate between unprocessed or 3′-processed DNA. Quantifying different types of viral DNA genome individually provides new information about the dynamics of all viral DNA forms and their interplay. For DNAL, we found that the 3′-processing reaction was efficient during the early stage of the replication cycle. Moreover, strand-transfer inhibitors (Dolutegravir, Elvitegravir, Raltegravir) affected 3′-processing differently. The comparisons of 2-LTRc accumulation mediated by either strand-transfer inhibitors or catalytic mutation of integrase indicate that 3′-processing efficiency did not influence the total 2-LTRc accumulation although the nature of the LTR-LTR junction was qualitatively affected. Finally, a significant proportion of 1-LTRc was generated concomitantly with reverse transcription, although most of the 1-LTRc were produced in the nucleus. We describe the fate of viral DNA forms during HIV-1 infection. Our study reveals the interplay between various forms of the viral DNA genome, the distribution of which can be affected by mutations and by inhibitors of HIV-1 viral proteins. In the latter case, the quantification of 3′-processed DNA in infected cells can be informative about the mechanisms of future integrase inhibitors directly in the cell context.

62 citations

Journal ArticleDOI
TL;DR: In this article, new dyes based on BODIPY and tetrazine fluorophores connected through a phenyl spacer have been synthesized and their absorption, emission and electrochemical properties characterized.

62 citations

Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the influence of small additions of highly-purified attapulgite clays (0.2% and 0.5% addition by mass of cement) on the adhesive properties of cement pastes.
Abstract: This study evaluates the influence of small additions of highly-purified attapulgite clays (0.2% and 0.5% addition by mass of cement) on the adhesive properties of cement pastes. Adhesive properties are measured by the tack test, a novel method of evaluating the rheological properties of granular materials. To better understand the results of the tack test as they pertain to cementitious materials, a highly concentrated material that is evolving due to thixotropic rebuilding and hydration, they are supplemented with a measure of the viscoelastic properties over time obtained through low-amplitude oscillatory shear rheometry. The influence of different preshear conditions and resting times (age of paste) on the adhesive properties are determined. Results show the tack test to be a suitable method for obtaining useful information about the adhesive properties and structural evolution of the material in the fresh state.

62 citations


Authors

Showing all 2722 results

NameH-indexPapersCitations
Shi Xue Dou122202874031
Olivier Hermine111102643779
John R. Reynolds10560750027
Shaul Mukamel95103040478
Tomás Torres8862528223
Ifor D. W. Samuel7460523151
Serge Abiteboul7327824576
Stéphane Roux6862719123
Zeger Debyser6740416531
Louis Nadjo6426412596
Praveen K. Thallapally6419012110
Andrew Travers6319313537
Shoji Takeuchi6369214704
Bineta Keita6327412053
Yves Mély6236813478
Network Information
Related Institutions (5)
École Polytechnique Fédérale de Lausanne
98.2K papers, 4.3M citations

92% related

École Normale Supérieure
99.4K papers, 3M citations

91% related

Georgia Institute of Technology
119K papers, 4.6M citations

91% related

University of Paris-Sud
52.7K papers, 2.1M citations

90% related

University of Paris
174.1K papers, 5M citations

90% related

Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20233
202222
202121
202029
201958
201879