Trivial, strongly minimal theories are model complete after naming constants

We prove that if is any model of a trivial, strongly minimal theory, then the elementary diagram is a model complete -theory. We conclude that all countable models of a trivial, strongly minimal theory with at least one computable model are -decidable, and that the spectrum of computable models of any trivial, strongly minimal theory is .

     

Conducive integral domains as pullbacks

This article presents a characterization of conducive (integral) domains as the pullbacks in certain types of Cartesian squares in the category of commutative rings. Such squares behave well with respect to (semi)normalization, thus permitting us to recover the recent characterization by Dobbs-Fedder of seminormal conducive domains. The conducive domains satisfying various finiteness conditions (Noetherian, Archimedean, accp) are characterized by identifying suitable restrictions on the data in the corresponding Cartesian squares. Various necessary or sufficient conditions are given for Mori conducive domains. Consequently, one has examples of several (accp non-Mori; Mori non-Noetherian) conducive domains.Work performed under the auspices of GNSAGA of Consiglio Nazionale delle Ricerche and Dipartimento di Matematica, Università di Roma La SapienzaSupported in part by grants from University of Tennessee Faculty Development Program and the Università di Roma La Sapienza     

Synthesis of triflouromethylated pyridinecarbonitriles

Enaminonitriles 1 react in mild conditions with β-trifluoroacetylvinyl ethers 2 to give the pyridine derivatives 4 . The reaction involves the formation of the intermediate 3 , that can be isolated when enol ether 2a is used.     

Characteristic features of polytypism in compounds with the La18W10O57‐type structure

Crystals with the La₁₈W₁₀O₅₇‐type structure (6H and 5H polytypes) were obtained by a self‐flux method from high‐temperature solutions. Some of the crystal samples were studied by single‐crystal X‐ray structure analysis. The diffraction patterns indicated that two phases co‐exist in each sample. The hexagonal lattices have a common period of a ≈ 9.0 Å and are non‐equal in length but have equally oriented superstructure periods 6c (phase I) and 5c (phase II), c ≈ 5.4 Å. The structures of phases I and II were solved in the symmetry groups P2c and P321, respectively, based on the X‐ray data for crystals I and II, with predominant content of the first and second phase. The motif of isolated WO₆ prisms with W atoms on the cell edges is common to both phases. WO₆ octahedra, both isolated and joined by faces, are distributed along the c axis within the unit cells. Phase I contains extra layers of isolated WO₆ octahedra compared to phase II. Tungsten sites in joined octahedra are disordered and partially occupied. Disordering is more expressed in phase II, which in return contains rather more W and O per atom of La. The refined chemical compositions are La₁₈W₁₀O₅₇ for I and La₁₅W_8.5O₄₈ for II.     

Palladium-assisted multicomponent synthesis of 2-aryl-4-aminoquinolines and 2-aryl-4-amino[1,8]naphthyridines

A palladium-mediated multicomponent domino reaction leading to 2-aryl-4-amino-quinolines and 2-aryl-4-amino[1,8]naphthyridines is reported. The scope of the reaction was examined using carbon monoxide, two 2-ethynyl-arylamines, four aryl iodides, and 10 primary amines as substrates. The selection of the appropriate catalytic system was achieved testing several palladium/phosphine systems and overrides previously reported drawbacks associated with the use of primary amines in related reactions. Moreover several features concerning the role of both palladium [(0) and (II)] and phosphines are reported.     

New synthesis of 2(1H)-pyridone derivatives

The reaction of N¹-acyl-2-ethoxycarbonylacetamidrazones 1 with diethyl ethoxymethylenemalonate (EMME) is reported. By refluxing equimolecular amounts of 1 and EMME in DMSO/toluene (or ethanol) solution, the 1-acylamino-2(1H)-pyridones 2 were obtained in good yield. When the reaction was performed in ethanolic solution in the presence of triethylamine, the 6-acylhydrazino-2(1H)-pyridones 3 were obtained.     

Variable-temperature NMR study of the enol forms of benzoylacetones

The enol forms of the beta-diketones, benzoylacetones, have been studied using long-range carbon-hydrogen couplings involving the chelate OH proton, O1H chemical shifts, 13C chemical shifts and deuterium isotope effects on 13C chemical shifts. Studies were done in the temperature range from 268 to 181 K. The compounds are shown to be tautomeric, in opposition to a more symmetrical, delocalised, close to one-potential well structure as found in the solid at very low temperature. The same is true for dibenzoylmethane. The isotope effects on chemical shifts are very sensitive gauges of structure in these almost symmetrical systems. Equilibrium constants are determined and related to other similar compounds.     

Cell penetrating silica nanoparticles doped with two-photon absorbing fluorophores

Organosilica nanoparticles, doped with two-photon absorbing distyrylbenzene derivatives, were prepared and studied as cell staining agents. Two dyes were used, bearing either two peripheral dimethylamino groups or one dimethylamino and one cyano group. Due to the internal charge transfer character of their excited state, the dyes employed show a red-shifted quenched emission in polar solvents. Once included in the particles, the properties of the two dyes undergo a substantial variation. Particles doped with the cyano substituted distyrylbenzene show a remarkable emission quantum yield in water, probably due to solvent exclusion from the nanoparticle core. To the contrary, the emission of the particles containing the dye substituted with two dimethylamino groups is substantially quenched. Fluorescence emission induced by two-photon absorption follows the same behaviour. The doped nanoparticles can be rapidly internalized by tumour cells with accumulation limited to the cytoplasm and show no cytotoxicity at low concentrations.     

Microstructural Evolution of Titanium Carbonitride Based Materials During Oxidation

 Ti(C, N) based materials represent a new class of hard and wear resistant structural materials. Nowadays, the main field of applications is focused on metal cutting and finishing operations. For these kinds of applications usually the mentioned materials work in oxidizing environments at high temperatures. The thermophysical stability under these conditions represents therefore a key factor that influences the material’s performance, and consequently the tool life of the component in service. The present study aimed to investigate the oxidation behaviour of two different Ti(C, N)-WC based materials, the first containing 0.9 wt% of Co and the second 6.2 wt% of Ni and 2.9 wt% of Co. Cycled oxidation tests (20 hours each) were conducted with a muffle furnace in laboratory static air at 1000 °C up to 100 hours. During the initial transitory stage the competition between the mass gain due to the formation of solid TiO₂ (rutile) and the mass loss due to released volatile W oxides controlled the mass change; thereafter the oxidation process obeyed a linear law. Great microstructural modifications occurred on the (sub)surfaces of the oxidized samples: multiphase TiO₂ based scales grew upon the external surfaces of the oxidized specimens. Kinetics and oxidation mechanisms were proposed and discussed.     

Confined space design by nanoparticle self-assembly

Nanoparticle (NP) self-assembly has led to the fabrication of an array of functional nanoscale systems, having diverse architectures and functionalities. In this perspective, we discuss the design and application of NP suprastructures (SPs) characterized by nanoconfined compartments in their self-assembled framework, providing an overview about SP synthetic strategies reported to date and the role of their confined nanocavities in applications in several high-end fields. We also set to give our contribution towards the formation of more advanced nanocompartmentalized SPs able to work in dynamic manners, discussing the opportunities of further advances in NP self-assembly and SP research.

This perspective gives an outlook on the design of interparticle confined nanocavities in self-assembled NP systems and their functional relevance.