Novel reactions with hetaryldieneamines as activated olefins

In the presence of appropriate reagents, hetaryldieneamines were found to react with only one of their two double bonds. Reaction with aryldiazonium salts resulted in hydrazone2 while azodicarboxylic ester afforded substitution product3. In reactions with benzofuroxan and arylazides, hetaryldieneamines reacted as enamines to yield quinoxaline (4) andv-triazole derivatives (5), respectively.

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Neue Reaktionen mit Hetaryldienaminen als aktivierte Olefine

Zusammenfassung Mit entsprechenden Reagenzien traten Hetaryldienamine nur mit einer der zwei Doppelbindungen in Reaktion. Die Umsetzung mit Aryldiazoniumsalzen führte zum Hydrazon2, währen Azodicarbonsäureester das Substitutionsprodukt3 ergab. In Reaktionen mit Benzofuroxan und mit Arylaziden reagierten die Dienamine1 als Enamine und es entstanden Chinoxalin-(4) bzw. Triazolderivate (5).

     

Composition and stability constants of iron- and copper-oxytetracycline chelates

Summary The composition and stability constants of iron and copper oxytetracycline chelates are determined by spectrophotometric and pH-metric methods. The stepwise stability constants are log ₁ 9.79, log ₂ 7.08, log ₃ 5.92 and log ₁ 7.28 and log ₂ 5.29 for iron and copper chelates, respectively. The thermodynamic parameters of these reactions and the site of chelation in oxytetracycline are also investigated. The reaction of iron(III) has been used for the spectrophotometric determination of oxytetracycline in some pharmaceutical preparations. Results with a coefficient of variation in the range of 1.6% and a mean recovery of 98.6% are obtained.

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Zusammensetzung und Stabilitätskonstanten der Eisen- und Kupferkomplexe mit Oxytetracyklin

Zusammenfassung Spektrophotometrische Methoden und pH-Messung ermöglichten die Bestimmung der im Titel angeführten Größen. Die Stabilitätskonstanten für die Eisen- bzw. Kupfer-Chelate sind: log/gb₁ 9,79; log ₂ 7,08; log ₃ 5,92; bzw. log ₁ 7,28; log ₂ 5,59. Die thermodynamischen Parameter dieser Reaktionen und die Art der Chelatbildung des Oxytetracyklin-Moleküls wurden ebenfalls untersucht. Die Reaktion mit Eisen(III) wurde für die Bestimmung von Oxytetracyklin verwendet. Ergebnisse mit einem Variationskoeffizienten 1,6% und einer mittleren Wiederfindungsrate von 98,6% wurden erzielt.

     

A tutorial on using genetic algorithms for the design of network topology

The design of network topology is an important part of network design, since network topology is directly associated with network operational behavior, capacity, reliability, and cost. This paper is a tutorial paper concerned with illustrating how the optimization capabilities of genetic algorithms can be used to design suitable network topologies considering basic topology problems. Simple genetic algorithms have been developed for the topology problem of mesh networks, considering single node and single link failure tolerance. The algorithms are based on criteria of two important measures: minimizing the length of communication links; and minimizing traffic flow through these links for given traffic loads. The first measure contributes to minimizing the cost of cabling, while the second measure contributes to minimizing the cost of link capacity. The work provides a useful approach and tools to network students and professionals concerned with the topology design of backbone networks. The developed software is made available on the Internet. Copyright © 2006 John Wiley & Sons, Ltd.     

Determination of cinnarizine in pharmaceutical preparations by spectrophotometry, atomic absorption spectrometry and potentiometry

New methods are developed for the determination of cinnarizine in various dosage forms. They are based on the reaction of cinnarizinium cation with cobalt tetrathiocyanate anion, whereby a sparingly soluble blue 21 drug: reagent ion-pair complex is quantitatively formed. The complex is (a) extracted with nitrobenzene and spectrophotometrically measured at 622 nm; (b) extracted with nitrobenzene and nebulized in an air-acetylene flame for atomic absorption spectrometric monitoring of cobalt at 242.5 nm; and (c) dispersed in a PVC membrane plasticized with 2-nitrophenyloctyl ether and used as a sensor for direct potentiometric determination of the drug. Optimum reaction conditions and performances of the three analytical techniques are evaluated and compared. At the 25 mg level of cinnarizine, the three methods give results with equal accuracy and precision. The average recovery is 98–99% of the nominal and the mean standard deviation is 0.7%. No significant interferences are caused by drug excipients and diluents.     

Shell model yrast states in the many-particle nucleus 72 157 Hf85

In-beam- andn-measurements have for the first time identified excited states in the ₇₂ ¹⁵⁷ Hf₈₅ nucleus and have established its yrast levels up to 6.5 MeV and I=(51/2). The results of parameter-free 11-particle recoupling calculations in the framework of the shell model for the configurationsh ₁₁ ^2/8 f ₇ ^2/3 andh ₁₁ ^2/8 f ₇ ^2/2 h_9/2 are in excellent agreement with the observed levels up to 39/2 at 4.758 MeV. A weakly populated 52 ns 29/2⁺ yrast isomer at 2.876 MeV is assigned as the three-neutron configurationf_7/2h_9/2i_13/2.     

Particle × phonon multiplets in 65 147 Tb82

High-spin states of¹¹⁵Sb were studied by inbeamγ-ray spectroscopy using the⁸⁹Y (²⁹Si, 2pn) fusionevaporation reaction at a beam energy of 108 MeV. The experiments includedγ-γ coincidence and directional correlation of oriented nuclei (DCO) ratio measurements using six BGO Compton suppressed Ge detectors. An intruderΔJ=2 rotational band has been identified for the first time and it is interpreted as the h_11/2 proton coupled to a two particle-two hole (2p ? 2h) deformed state of the¹¹⁴Sn core. A ΔJ=1 rotational band based on the 2p ? 1h, π{g ₇ ^2/2 ?g ₉ ^2/?1 }, configuration has been extended to the 29/2⁺ state at an excitation energy of 5241 keV.     

Ballistic mobility and saturation velocity in low-dimensional nanostructures

Ohm's law, a linear drift velocity response to the applied electric field, has been and continues to be the basis for characterizing, evaluating performance, and designing integrated circuits, but is shown not to hold its supremacy as channel lengths are being scaled down. In the high electric field, the collision-free ballistic transport is predicted, while in low electric field the transport remains predominantly scattering-limited in a long-channel. In a micro/nano-circuit, even a low logic voltage of 1 V gives an electric field that is above its critical value ε_c (ε?ε_c) triggering non-ohmic behavior that results in ballistic velocity saturation. The saturation velocity is an appropriate thermal velocity for a non-degenerate and Fermi velocity for a degenerate system with given dimensionality. A quantum emission may lower this ballistic velocity. The collision-free ballistic mobility in the ohmic domain arises when the channel length is smaller than the mean free path. The results presented will have a profound influence in interpreting the data on a variety of low-dimensional nanostructures.     

Weak solutions for immiscible compressible multifluid flows in porous media

We consider a multifluid flow model describing evolution of pressures and relative saturations of non-miscible and compressible phases in porous media. This model is obtained by a macroscopic representation of the flow. It takes into account capillary effects and velocity fields are described by Darcy laws. Global weak solutions for such a model is introduced. To cite this article: C. Galusinski, M. Saad, C. R. Acad. Sci. Paris, Ser. I 347 (2009).     

Three‐dimensional Stokes flow caused by a translating–rotating sphere bisected by a free surface bounding a semi‐infinite micropolar fluid

Explicit velocity and microrotation components and systematic calculation of hydrodynamic quasistatic drag and couple in terms of nondimensional coefficients are presented for the flow problem of an incompressible asymmetrical steady semi‐infinite micropolar fluid arising from the motion of a sphere bisected by a free surface bounding a semi‐infinite micropolar fluid. Two asymmetrical cases are considered for the motion of the sphere: parallel translation to the free surface and rotation about a diameter which is lying in the free surface. The speed of the translational motion and the angular speed for the rotational motion of the sphere are assumed to be small so that the nonlinear terms in the equations of motion can be neglected under the usual Stokesian approximation. A linear slip, Basset‐type, boundary condition has been used. The variation of the resistance coefficients is studied numerically and plotted versus the micropolarity parameter and slip parameter. The two limiting cases of no‐slip and perfect slip are then recovered. Copyright © 2008 John Wiley & Sons, Ltd.