About the synthesis of N-1-substituted 3-aminopyrroles. A comparison

A general method for the preparation of 3-amino-1-methylpyrroles in excellent yields is reported. The key step involves the N-methylation of the nitro derivatives 2 , under phase transfer catalysis conditions.     

Moment redistribution in continuous reinforced concrete beams strengthened with carbon-fiber-reinforced polymer laminates

The results of tests on continuous steel-fiber-reinforced concrete (RC) beams, with and without an external strengthening, are presented. The internal flexural steel reinforcement was designed so that to allow steel yielding before the collapse of the beams. To prevent the shear failure, steel stirrups were used. The tests also included two nonstrengthened control beams; the other specimens were strengthened with different configurations of externally bonded carbon-fiber-reinforced polymer (CFRP) laminates. In order to prevent the premature failure from delamination of the CFRP strengthening, a wrapping was also applied. The experimental results obtained show that it is possible to achieve a sufficient degree of moment redistribution if the strengthening configuration is chosen properly, confirming the results provided by two simple numerical models. Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 43, No. 5, pp. 667–686, September–October, 2007.     

Poly condensed nitrogen heterocycles. V. Two novel ring systems: Pyrazolo[5,1-c]-1,2,4-thiadiazine and pyrazolo[3,4-c]-1,2-thiazine

The title compounds were obtained by reaction of aminopyrazoles IV and VII with ω-acetophenonesulfonyl chloride (II, R = C₆H₅). In agreement with the general pattern of the distribution of electron density in the pyrazole nucleus, this work confirms that the position 4 of ring is the favoured site of electrophilic attacks.     

Role of beam propagation in Goos-Hänchen and Imbert-Fedorov shifts

We derive the polarization-dependent displacements parallel and perpendicular to the plane of incidence for a Gaussian light beam reflected from a planar interface, taking into account the propagation of the beam. Using a classical-optics formalism we show that beam propagation may greatly affect both Goos-H?nchen and Imbert-Fedorov shifts when the incident beam is focused.     

Synthesis and solid state characterization of hexacoordinated 1:1 ionic gallium(III) complexes

The coordination of the N,N ligands 2,2-bipyridine (bipy) and 1,10-phenanthroline (phen) to Ga(III) has been investigated via the formation of new ionic hexacoordinated complexes of general formula [Q'(2)Ga(N,N)][X], where HQ' stands for 2-methyl-8-hydroxyquinoline and the counter anion X(-) is nitrate (NO(3)(-)) or hexafluorophosphate (PF(6)(-)). All synthesized complexes were characterized by single-crystal X-ray diffraction analysis. The geometry of the Ga(III) cations is octahedral and a single geometric isomer (all N, N trans conformation) has been obtained in all cases. The role of both the N,N ligand and the counter anion has been investigated in the formation of the crystal supramolecular motifs occurring in the 3D-crystal networks of these new class of ionic Ga(III) derivatives. A full investigation of the photophysical properties of the new synthesized ionic species is reported and discussed in relation to their crystalline packing and the degree of crystallinity of thin solid films as well as the nature of the N,N ligand and the counter anion.     

XPS and AFM characterization of the enzyme glucose oxidase immobilized on SiO(2) surfaces

A process to immobilize the enzyme glucose oxidase on SiO2 surfaces for the realization of integrated microbiosensors was developed. The sample characterization was performed by monitoring, step by step, oxide activation, silanization, linker molecule (glutaraldehyde) deposition, and enzyme immobilization by means of XPS, AFM, and contact angle measurements. The control of the environment during the procedure, to prevent silane polymerization, and the use of oxide activation to obtain a uniform enzyme layer are issues of crucial importance. The correct protocol application gives a uniform layer of the linker molecule and the maximum sample surface coverage. This result is fundamental for maximizing the enzyme bonding sites on the sample surface and achieving the maximum surface coverage. Thin SiO2 layers thermally grown on a Si substrate were used. The XPS Si 2p signal of the substrate was monitored during immobilization. Such a signal is not completely shielded by the thin oxide layer and it is fully suppressed after the completion of the whole protocol. A power spectral density analysis on the AFM measurements showed the crucial role of both the oxide activation and the intermediate steps (silanization and linker molecule deposition) to obtain uniform immobilized enzyme coverage. Finally, enzymatic activity measurements confirmed the suitability of the optimized protocol.     

Angular spectrum of quantized light beams

We introduce a generalized angular spectrum representation for quantized light beams. By using our formalism, we are able to derive simple expressions for the electromagnetic vector potential operator in the case of (a) time-independent paraxial fields, (b) time-dependent paraxial fields, and (c) nonparaxial fields. For the first case the well-known paraxial results are fully recovered.     

Cognitive aspects of chaos in random networks

A special case of deterministic chaos that is independent of the architecture of the connections has been observed in a computer model of a purely excitatory neuronal network. Chaos onsets when the level of connectivity is critically low. The results indicate a typical period-doubling route to chaos as the connectivity decreases. A cognitive interpretation of such type of chaos, based on information theory and phase-transitions, is proposed.     

Polycondensed nitrogen heterocycles. Part 24. Pyrrolo[3,4-c]isoquinolinone by thermal rearrangement of a pyrrolylbenzotriazinone

Rearrangement under acidic conditions of the pyrrolylbenzotriazinone 7 afforded the pyrrolylbenzamides 10 and 11 . By thermal rearrangement instead, the first fully aromatic derivative of the pyrrolo[3,4-c]isoquinoline ring system 9 was obtained.     

The safety assessment of herbals with a new and ethical approach

The increasing use of plant medicines (herbals) in Europe needs a shared methodology to determine the toxicity and the daily exposure level to these drugs. For this reason, the European regulatory agencies have undertaken a study that could meet popular uses and toxicological research in different countries of the Union. Here we list some examples of the most used herbal drug classes and we propose a decision-making process based on their characteristics, their content in active principles and on the basis of the present scientific pharmacological and toxicological literature. The proposed decision tree actually makes easier for the assessor to quickly and accurately evaluate the accredited indexes for risk and toxicity assessment based on the preclinical literature data and using the correct classification that some of them may have because they are already present in medicinal products or used as food.