Exact Controllability of a Faedo–Galërkin Scheme for the Dynamics of Polymer Fluids

Journal of Optimization Theory and Applications - We describe the dynamics of fluids with scattered polymer chains through a multi-field model accounting for weakly non-local inertia and...     

Densely-packed self-assembled monolayers on gold surfaces from a conformationally constrained helical hexapeptide

A novel hexapeptide was functionalized at the N-terminus by a lipoyl group for binding to gold substrates. Owing to the high content of α-aminoisobutyric acid residues, the peptide adopts a rigid helical conformation despite the shortness of its main chain. Binding of the peptide to gold was investigated by quartz crystal microbalance, cyclic voltammetry, X-ray photoelectron spectroscopy, and scanning tunneling microscopy under ultra-high vacuum conditions. Scanning tunneling microscopy experiments revealed that the peculiar self-assembly properties of this short helical peptide determine the complex morphology of the monolayer, showing ‘stripes’, i.e. peptide aggregates horizontally layered on the gold surface, and ‘holes’, i.e. Au vacancy islands coated by the peptide monolayer.     

Necessary and Sufficient Conditions for Strong Fenchel–Lagrange Duality via a Coupling Conjugation Scheme

Given a general primal problem and its Fenchel–Lagrange dual one, which is obtained by using a conjugation scheme based on coupling functions and the perturbational approach, the aim in this work is to establish conditions under which strong duality can be guaranteed. To this purpose, even convexity and properness are a compulsory requirement over the involved functions in the primal problem. Furthermore, two closedness-type regularity conditions and a characterization for strong duality are derived.     

Some results on quasipolyhedral convexity

The objective of this paper is to analyze under what well-known operations the class of quasipolyhedral convex functions, which can be regarded as an extension of that of polyhedral convex functions, is closed. The operations that will be considered are those that preserve polyhedral convexity, such that the image and the inverse image under linear transformations, right scalar multiplication (including the case where λ=0⁺) and pointwise addition.      

Structural and Electronic Properties Study of Colombian Aurifer Soils by Mössbauer Spectroscopy and X-ray Diffraction

In this work a study on gold mineral samples is reported, using optical microscopy, X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The auriferous samples are from the El Diamante mine, located in Guachavez-Nariño (Colombia) and were prepared by means of polished thin sections. The petrography analysis registered the presence, in different percentages that depend on the sample, of pyrite, quartz, arsenopyirite, sphalerite, chalcopyrite and galena. The XRD analysis confirmed these findings through the calculated cell parameters. One typical Rietveld analysis showed the following weight percent of phases: 85.0% quartz, 14.5% pyrite and 0.5% sphalerite. In this sample, MS demonstrated the presence of two types of pyrite whose hyperfine parameters are δ ₁ = 0.280 ± 0.002 mm/s and Δ ₁ = 0.642 ± 0.002 mm/s, δ ₂ = 0.379 ± 0.002 mm/s and Δ ₂ = 0.613 ± 0.002 mm/s.     

Walk of a Line Defect in Quasicrystals

Quasicrystalline alloys are quasiperiodic aggregates in which local atomic changes (phason activity) influence prominently the gross deformative behavior. The effects of these rearrangements on a line defect are analyzed here. Balances of standard and phason interactions are derived along the line together with the balance of actions driving eventually it the former are found to be covariant while the latter follows from a requirement of invariance with respect to the action of the group of isochoric diffeomorphisms. The results can be applied to the analysis of dislocations in quasicrystals.     

Thiolato gold(I) complexes containing water-soluble phosphane ligands: a characterization of their chemical and biological properties

A series of thiolate gold(I) derivatives bearing water soluble phosphanes--namely sodium triphenylphosphane monosulfonate (TPPMS), sodium triphenylphosphane trisulfonate (TPPTS), 1,3,5-triaza-7-phosphaadamantane (PTA) and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA)--is reported and the compounds studied for their luminescence properties in the solid state. Two of these derivatives, [Au(SMe(2)pyrim)(PTA)] and [Au(SBenzoxazole)(DAPTA)], are also structurally characterized by X-ray diffraction analysis. Strong antiproliferative effects are observed for most of the compounds in the human ovarian carcinoma cell lines (A2780/S) and its cisplatin-resistant variant (A2780/R), which depend on both the type of thiolate and phosphane ligands. ICP-MS studies were also performed to evaluate the influence of the gold uptake on the cytotoxic potency of the compounds.     

Sparse Dirichlet optimal control problems

Computational Optimization and Applications - In this paper, we analyze optimal control problems governed by an elliptic partial differential equation, in which the control acts as the Dirichlet...