The small quantum cohomology of a weighted projective space, a mirror D-module and their classical limits

We first describe a mirror partner (B-model) of the small quantum orbifold cohomology of weighted projective spaces (A-model) in the framework of differential equations: we attach to the A-model (resp. B-model) a quantum differential system (that is a trivial bundle equipped with a suitable flat meromorphic connection and a flat bilinear form) and we give an explicit isomorphism between these two quantum differential systems. On the A-side (resp. on the B-side), the quantum differential system alluded to is naturally produced by the small quantum cohomology (resp. a solution of the Birkhoff problem for the Brieskorn lattice of a Landau–Ginzburg model). Then we study the degenerations of these quantum differential systems and we apply our results to the construction of (classical, limit, logarithmic) Frobenius manifolds.     

Vibrationally resolved K-shell photoionization cross sections of methane

We use an extension of the static-exchange density functional theory (DFT) method, previously reported in [E. Plésiat et al., Phys. Rev. A 2, 023409 (2012), E. Plésiat, P. Decleva, F. Martín, Phys. Chem. Chem. Phys. 31, 10853 (2012)], to evaluate vibrationally resolved (total and angular) K-shell photoelectron cross sections of methane. The calculated cross sections are in very good agreement with the existing experimental measurements at low photoelectron energies. We show that, in contrast with the rich interference patterns previously observed in molecular frame C(1s) photoelectron angular distributions of methane at both low and high photoelectron energy, no interference effects are observed in the calculated β parameters, even at high photon energies.     

Autour de la condition d'engel dans les algèbres de bernstein

We know that, in general, an algebra satisfying an Engel's condition is a nilalgebra. But an Engel's condition don't implies necessarily the nilpotency of the algebra. In this paper we show that every Bernstein algebra satisfying the second or the third Engel's condition is genetic, that is, the kernel of his weight fonction is nilpotent. This is also the case for a Bernstein algebra satisfying the second weak Engel's condition.

On sait que, en général, toute algèbre vérifiant une condition d'Engel est une nilalgèbre. Cependant, une condition d'Engel n'entraîne pas nécessairement la nilpotence de l'algèbre. Nous montrons, dans ce papier, que taute algèbre de Bernstein vérifiant la deuxième ou la troisième condition d'Engel est génétique, c'est-à-dire, le noyau de sa pondération est nilpotent. C'est aussi le cas pour la deuxième condition faible d'Engel.     

Aqueous Electrochemical Reduction of Carbon Dioxide and Carbon Monoxide into Methanol with Cobalt Phthalocyanine

Conversion of CO₂ into valuable molecules is a field of intensive investigation with the aim of developing scalable technologies for making fuels using renewable energy sources. While electrochemical reduction into CO and formate are approaching industrial maturity, a current challenge is obtaining more reduced products like methanol. However, literature on the matter is scarce, and even more for the use of molecular catalysts. Here, we demonstrate that cobalt phthalocyanine, a well‐known catalyst for the electrochemical conversion of CO₂ to CO, can also catalyze the reaction from CO₂ or CO to methanol in aqueous electrolytes at ambient conditions of temperature and pressure. The studies identify formaldehyde as a key intermediate and an unexpected pH effect on selectivity. This paves the way for establishing a sequential process where CO₂ is first converted to CO which is subsequently used as a reactant to produce methanol. Under ideal conditions, the reaction shows a global Faradaic efficiency of 19.5 % and chemical selectivity of 7.5 %.     

Synthesis and Structures of Stable PtII and PtIV Alkylidenes: Evidence for π-Bonding and Relativistic Stabilization

Isolable cationic Pt^II and Pt^IV alkylidenes, proposed intermediates in catalytic organic transformations, are reported. The bonding in these species was probed by experimental, structural, spectroscopic, electrochemical and computational methods, providing direct evidence for π-bonding, the often-theorized relativistic stabilization of these species, and the influence of oxidation state.     

Extinction time and the total mass of the continuous-state branching processes with competition

Consider a general continuous-state branching process with additional interaction, which destroys the branching property. We give precise conditions on the interaction term, in order to decide whether the extinction time of the process remains or not bounded as the initial value tends to infinity, and similarly for the total mass of the process.     

Photocurable Sol-Gel Coatings: Channel Waveguides for Use at 1.55 μm

The development and characterization of channel waveguides using wet-process, low temperature sol-gel chemistry is described. Two structures have been developed. The first one is a one-layer structure, composed of a sol-gel solution which is a mixture of photopolymerizable organosilicate and organozirconate precursors. The other is a multilayer structure with a buffer under the guide and a protective coating. The layers are deposited by the dipping technique. The devices are obtained by UV light exposure of the coating through a predefined mask (channel waveguides). The refractive index increase is sufficient enough to allow the use of waveguides in the 1.55 m telecommunication window.These waveguides are thick enough to reduce the coupling losses with an optical fiber below 0.5 dB. Also, because of our sandwich structure, the propagation losses are less than 0.1 dB.     

Inverse Polyamidoamine (i-PAMAM) Dendrimer Antimicrobials

Here we redesigned the branches of polyamidoamine (PAMAM) dendrimers by moving the amide carbonyl group on the other side of the amide nitrogen atom, transforming the β-alaninyl-amidoethylamine branch, which easily undergoes retro-Michael reactions and renders PAMAMs intrinsically unstable, into a more stable glycyl-amidopropylamine branch. The resulting inverse PAMAM (i-PAMAM) dendrimers have the same carbon framework as PAMAMs and only differ by the position of the carbonyl group. In contrast to PAMAMs which are prepared in solution and are difficult to purify, we synthesize i-PAMAMs using high-temperature solid-phase peptide synthesis by iterative coupling and deprotection of the commercially available N,N-bis(N′-Fmoc-3-aminopropyl)glycine and purify them preparative reverse phase HPLC. Our i-PAMAM dendrimers show no detectable degradation over time. We demonstrate this new class of dendrimers with the synthesis of antimicrobial dendrimers with potent yet non-membrane disruptive activities against both Gram-negative and Gram-positive bacteria.