Effect of Light Environment on Growth and Phenylpropanoids of Yarrow (Achillea collina cv. SPAK) Grown in the Alps

A 2‐year field study on the effect of different light environments, obtained by using cladding materials (polyethylene films and shade net) able to cut off specific regions of the photosynthetically active radiation and ultraviolet wavebands, on the growth and phenylpropanoids content of Achillea collina grown in the Alps was conducted. Overall the plant growth was strongly enhanced in the second growing season irrespective of radiation treatment. The light environment did not affect total biomass accumulation, but only carbon allocation to leaves or inflorescences. Indeed the phenylpropanoid levels in inflorescences appeared to be more sensitive to the light environment than leaves as the latter showed high constitutive amounts of these compounds. However, the use of polyethylene films improved to some extent the content of caffeic acid derivatives in leaves. Our results showed that yarrow production, in the alpine situation considered, is influenced by the growing season and the light environment, providing a basis to optimize its quality, depending on the concentration of bioactive compounds, by means of proper agronomic practices.     

A Carborane‐Derivative “Click” Reaction under Heterogeneous Conditions for the Synthesis of a Promising Lipophilic MRI/GdBNCT Agent

In this study, the Huisgen reaction has been used to functionalise a carborane cage with a lipophilic moiety and a 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) ligand to obtain a new Gd boron neutron‐capture therapy (BNCT)/magnetic resonance imaging (MRI) agent. The introduction of the triazole units has been accomplished under both heterogeneous conditions, by the use of a Cu‐supported ionic‐liquid catalyst, and homogeneous conditions. The ability of the Gd complex of the synthesised ligand to form stable adducts with low‐density lipoproteins (LDLs) has been evaluated and then MRI has been performed on tumour melanoma cells incubated in the presence of a Gd‐complex/LDL imaging probe. It has been concluded that the high amount of intracellular boron necessary to perform BNCT can be reached even in the presence of a relatively low‐boron‐containing LDL concentration.     

Local Lipschitz continuity of graphs with prescribed Levi mean curvature

We prove interior gradient estimates of viscosity solutions of the prescribed Levi mean curvature equation. The second author was partially supported by Indam, within the interdisciplinary project “Nonlinear subelliptic equations of variational origin in contact geometry”.     

Synthesis of 4(5)-phenacyl-imidazoles from isoxazole side-chain rearrangements

A novel base-induced rearrangement of isoxazoles into imidazole derivatives is reported. In the isoxazole series, this represents the first example of a three-atom side-chain rearrangement involving a CNC sequence. The reactions are carried out under nitrogen and produced 2-aryl-4(5)-phenacyl-5(4)-phenyl-imidazoles in high yields. In the presence of oxygen, a cascade rearrangement-oxidation reaction sequence was observed and imidazole derivatives bearing an oxidized side-chain were isolated.     

MnO x /ZrO2 gel-derived materials for hydrogen peroxide decomposition

Manganese-yttrium-zirconium mixed oxide nanocomposites with three different Mn loadings (5, 15 and 30 wt%) were prepared by sol–gel synthesis. Amorphous xerogels were obtained for each composition. Their structural evolution with the temperature and textural properties were examined by thermogravimetry/differential thermal analysis, X-ray diffraction, diffuse reflectance UV–vis spectroscopy and N₂ adsorption isotherms. Mesoporous materials with high surface area values (70–100 m² g⁻¹) were obtained by annealing in air at 550 °C. They are amorphous or contain nanocrystals of the tetragonal ZrO₂ phase (T-ZrO₂) depending on the Mn amount and exhibit Mn species with oxidation state higher than 2 as confirmed by temperature programmed reduction experiments. T-ZrO₂ is the only crystallizing phase at 700 °C while the monoclinic polymorph and Mn₃O₄ start to appear only after a prolonged annealing at 1,000 °C. The samples annealed at 550 °C were studied as catalysts for H₂O₂ decomposition in liquid phase. Their catalytic activity was higher than that of previously studied Mn/Zr oxide systems prepared by impregnation. Catalytic data were described by a rate equation of Langmuir type. The decrease of catalytic activity with time was related to dissolution of a limited fraction (up to 15%) of Mn into the H₂O₂/H₂O solution.     

Lipschitz continuity and duality for dynamic oligopolistic market equilibrium problem with memory term

We are concerned with an infinite dimensional variational inequality which is connected with the dynamic oligopolistic market equilibrium problem. We will provide existence theorems and show, under minimal assumptions on the data, the Lipschitz continuity of the solution. Moreover a general duality theory is provided overcoming the difficulty of the voidness of the interior of the ordering cone which defines the cone constraints.     

A two-dimensional strip cutting problem with sequencing constraint

We study a strip cutting problem that arises in the production of corrugated cardboard. In this context, rectangular items of different sizes are obtained by machines, called corrugators, that cut strips of large dimensions according to particular schemes containing at most two types of items. Because of buffer restrictions, these schemes have to be sequenced in such a way that, at any moment, at most two types of items are in production and not completed yet (sequencing constraint). We show that the problem of finding a set of schemes of minimum trim loss that satisfies an assigned demand for each item size is strongly NP-hard, even if the sequencing constraint is relaxed. Then, we present two heuristics for the problem with the sequencing constraint, both based on a graph characterization of the feasible solutions. The first heuristic is a two-phase procedure based on a mixed integer linear programming model. The second heuristic follows a completely combinatorial approach and consists of solving a suitable sequence of minimum cost matching problems. For both procedures, an upper bound on the number of schemes (setups) is found. Finally, a computational study comparing the quality of the heuristic solutions with respect to an LP lower bound is reported.     

Inner cladding influence on mode interaction in symmetry-free photonic crystal fibers under heat load

A further output power scaling of Yb-doped double-cladding photonic crystal fiber lasers, required for practical applications in many industrial fields, is currently prevented by thermal effects, which significantly worsen the beam quality. In this work the mode interaction and, consequently, the single-mode regime of Yb-doped air-silica symmetry-free photonic crystal fibers have been numerically investigated in different heat load conditions using simulation tools based on the finite element method. The effect of the main inner cladding geometric parameters, in particular of the inner cladding dimension, on the guided-mode delocalization has been analyzed, with the aim to identify a design of the large mode area active fiber providing single-mode operation despite the presence of thermal effects. Simulation results have demonstrated that the inner cladding enlargement causes a stronger coupling between core-guided and cladding modes, as well as an increase of the differential overlap between fundamental and first higher-order mode for moderate heat load values. However, the inner cladding influence becomes less important under severe heat load, being the fiber behaviour mainly affected by the thermally-induced refractive index change in the doped core.     

Pseudoconvex fully nonlinear partial differential operators: strong comparison theorems

We introduce a new class of curvature PDOs describing relevant properties of real hypersurfaces of . In our setting, the pseudoconvexity and the Levi form play the same role as the convexity and the real Hessian matrix play in the real Euclidean one. Our curvature operators are second-order fully nonlinear PDOs not elliptic at any point. However, when computed on generalized s-pseudoconvex functions, we shall show that their characteristic form is nonnegative definite with kernel of dimension one. Moreover, we shall show that the missing ellipticity direction can be recovered by taking into account the CR structure of the hypersurfaces. These properties allow us to prove a strong comparison principle, leading to symmetry theorems for domains with constant curvatures and to identification results for domains with comparable curvatures.