Metaheuristics for multiobjective optimisation

This is a summary of the author’s PhD thesis supervised by Laetitia Jourdan and El-Ghazali Talbi and defended on 8 December 2009 at the Université Lille 1. The thesis is written in French and is available from . This work deals with the design, implementation and experimental analysis of metaheuristics for solving multiobjective optimisation problems, with a particular interest on hard and large combinatorial problems from the field of logistics. After focusing on a unified view of multiobjective metaheuristics, we propose new cooperative, adaptive and parallel approaches. The performance of these methods are experimented on a scheduling and a routing problem involving two or three objective functions. We finally discuss how to adapt such metaheuristics during the search process in order to handle uncertainty that may occur from many different sources.     

1D quintic nonlinear Schrödinger equation with white noise dispersion

In this article, we improve the Strichartz estimates obtained in A. de Bouard, A. Debussche (2010) [12] for the Schrödinger equation with white noise dispersion in one dimension. This allows us to prove global well posedness when a quintic critical nonlinearity is added to the equation. We finally show that the white noise dispersion is the limit of smooth random dispersion.     

Relatively compact Siegel disks with non-locally connected boundaries

We construct holomorphic maps f with a Siegel disk whose boundary is not locally connected (and is an indecomposable continuum), yet compactly contained in the domain of definition of the map. Our examples are injective and defined on a subset of \mathbb C{\mathbb C}.     

The stimulating adventure of KRN 7000

Associated with the CD1d protein, KRN 7000, a potent synthetic α-galactosylceramide, is known to activate the invariant NKT immune cells. This stimulation then leads to the production of different cytokines modulating a T(H)1/T(H)2 immune response balance involved in protection against several pathologies such as autoimmune diseases and cancers. Various efforts have been made toward the synthesis of simple and more functionalized analogues in order to selectively induce T(H)1 or T(H)2-type cytokine production. Since the discovery of KRN 7000, structure-activity relationships, crystallographic and modelling studies have pointed to the potential of several GalCer analogues in term of selective bioactivity, and have highlighted interesting elements in order to better understand the recognition and activation mechanisms of immune iNKT cells. By presenting an up-to-date library of analogues, collecting recent breakthroughs done in crystallography and molecular modelling, and relating them to the available biological results, we hope that this review will highlight and help the scientific community in their KRN research.     

A platinum Chugaev carbene complex as a potent anticancer agent

A platinum Chugaev complex was synthesised and fully characterized by multinuclear NMR spectroscopy and X-ray crystallography. This cis bis acyclic diamino carbene complex acts as a cytotoxic compound and behaves as a cisplatin equivalent by interacting with supercoiled DNA and thiols. Stability of the ligand is also discussed.     

Cytosine: para-sulphonato-calix[4]arene assemblies: in solution, in the solid-state and on the surface of hybrid silver nanoparticles

The molecular recognition by para-sulphonato-calix[4]arene of cytosine, occurs in solution, in the solid-state and by assembly on the surface of para-sulphonato-calix[4]arene capped silver nanoparticles. Each of these states shows different modes of assembly; in solution a 1:1 complex is formed; in the solid state a 4:1 assembly exists, however some of the cytosine molecules are present as space fillers and do not participate in the host (guest complexes, finally on the surface of the hybrid silver/para-sulphonato-calix[4]arene nanoparticles a 2:1 cytosine/para-sulphonato-calix[4]arene assembly is observed. The assembly processes have been studied by DOSY NMR, fluorescence spectroscopy, Dynamic Light Scattering (DLS), Single Crystal Solid State Diffraction, Visible Spectroscopy and Electron Microscopy. The results demonstrate how cytosine initiates the aggregation of the hybrid silver/para-sulphonato-calix[4]arene hybrid nanoparticles.     

Three‐Dimensional MOF‐Type Architectures with Tetravalent Uranium Hexanuclear Motifs (U6O8)

Four metal–organic frameworks (MOF) with tetravalent uranium have been solvothermally synthesized by treating UCl₄ with rigid dicarboxylate linkers in N,N‐dimethylfomamide (DMF). The use of the ditopic ligands 4,4′‐biphenyldicarboxylate ( 1 ), 2,6‐naphthalenedicarboxylate ( 2 ), terephthalate ( 3 ), and fumarate ( 4 ) resulted in the formation of three‐dimensional networks based on the hexanuclear uranium‐centered motif [U₆O₄(OH)₄(H₂O)₆]. This motif corresponds to an octahedral configuration of uranium nodes and is also known for thorium in crystalline solids. The atomic arrangement of this specific building unit with organic linkers is similar to that found in the zirconium‐based porous compounds of the UiO‐66/67 series. The structure of [U₆O₄(OH)₄(H₂O)₆(L)₆] ? X (L=dicarboxylate ligand; X=DMF) shows the inorganic hexamers connected in a face‐centered cubic manner through the ditopic linkers to build up a three‐dimensional framework that delimits octahedral (from 5.4 Å for 4 up to 14.0 Å for 1 ) and tetrahedral cavities. The four compounds have been characterized by using single‐crystal X‐ray diffraction analysis (or powder diffraction analysis for 4 ). The tetravalent state of uranium has been examined by using XPS and solid‐state UV/Vis analyses. The measurement of the Brunauer–Emmett–Teller surface area indicated very low values (Langmuir <300 m² g^?1 for 1 , <7 m² g^?1 for 2 – 4 ) and showed that the structures are quite unstable upon removal of the encapsulated DMF solvent.     

Vacuum Ultraviolet Action Spectroscopy of Polysaccharides

We studied the optical properties of gas-phase polysaccharides (maltose, maltotetraose, and maltohexaose) ions by action spectroscopy using the coupling between a quadrupole ion trap and a vacuum ultraviolet (VUV) beamline at the SOLEIL synchrotron radiation facility (France) in the 7 to 18 eV range. The spectra provide unique benchmarks for evaluation of theoretical data on electronic transitions of model carbohydrates in the VUV range. The effects of the nature of the charge held by polysaccharide ions on the relaxation processes were also explored. Finally the effect of isomerization of polysaccharides (with melezitose and raffinose) on their photofragmentation with VUV photons is presented.

Studies of Radical Alternating Copolymerization. I. Quantitative Determination of the Relative Reactivities between Free Comonomers and a Complex between Them; A Theoretical Treatment in Terms of Frontier Molecular Orbital Interactions. Application to Radical Maleic Anhydride-Vinyl Acetate Alternating Copolymerization

A simple quantitative determination of the ratio β₁ of rate constants k_ij corresponding to the addition of a complex or a free monomer on a same growing chain in alternating copolymerization was determined. The application of this method to the case of alternating maleic anhydride (A)-vinyl acetate (D) copolymerization give for β₁ = k_AC/k_AD and for β₂ = k_DC/k_DA (C refers to the complex) the respective values of 7 and 0. A complex was more reactive than A but less reactive than D toward a growing chain. In order to explain these reactivities, a frontier molecular orbital treatment was proposed. A good qualitative correlation with experimental results was obtained.     

Gradient elution method in centrifugal partition chromatography for the separation of a complex sophorolipid mixture obtained from Candida bombicola yeasts

Sophorolipids represent an important class of natural surfactants with a variety of environmental, cosmetic, and pharmaceutical applications. Despite their promising physicochemical and biological properties, the use of sophorolipids is hampered by the lack of information regarding their individual structure‐activity relationships. The major difficulty in isolating pure sophorolipids arises from the high complexity of crude fermentation media composition and from their strong structural similarities. In this work, a centrifugal partition chromatography method was developed in an original gradient elution mode for the separation of sophorolipids produced by the yeast Candida bombicola. Experiments were realized by using three sets of solvent systems composed of n‐heptane, ethyl acetate, n‐butanol, methanol, and water in different proportions. The separation was performed at 5 mL/min in the ascending mode by increasing progressively the polarity of the organic mobile phase. In these conditions, more than 80% of the sophorolipids present in the initial crude fermentation extract were eluted successively from the most hydrophobic lactone forms to the most hydrophilic acid forms. The structures of the isolated sophorolipids were further elucidated by HPLC and NMR analyses.