Combined study of anion recognition by a carbazole-based neutral tripodal receptor in a competitive environment

Anion recognition studies have been carried out on a series of neutral synthetic receptors in which carbazole-2-carboxamide has been used as building block. Different ligands which include one to three carbazole units in their structure have been prepared. Binding experiments have been performed under competitive conditions in DMSO and DMSO-water solutions. The tripodal receptor offered a better host-guest association due to the synergistic effect of a well arranged set of hydrogen bonds. A selective response towards the biologically important pyrophosphate anion has been achieved. This selectivity is enhanced when studies are carried out with an increasing water content, which gets as high as 20% (v/v) in NMR experiments. The significance of this result lies in the use of a neutral receptor which exclusively interacts with the anionic guest through hydrogen bonding. The influence of multiple equilibria in the studied system has been analysed. Several techniques ((1)H NMR, (31)P NMR, mass spectrometry, diffusion-NMR, ITC, absorption and emission spectroscopy) have been employed to get a better understanding of the different processes taking place in solution for the evaluated receptors.     

Pulse polarography: Part V. on the theory for the kinetic currents with an ece mechanism

We have derived an equation for the instantaneous limiting current in pulse polarography with an ECE mechanism. That equation has been derived for the expanding sphere electrode model (and also for the expanding plane electrode model) with the condition (k₁+k₂)>>1, k₁ and k₂ being the rate constants of the chemical reaction. We show that by an adequate choice of the time of application of the potential and time of the drop growth prior to potential application, it is possible — if the equilibrium constant for chemical reaction is known — to widen the interval of values for k₁ and k₂ that may be determined using this technique. At the same time, we also show that if the electrode sphericity is not taken into account, the values obtained for k₁ and k₂ are always lower than the real ones.     

An approximate global solution of Einstein’s equation for a rotating compact source with linear equation of state

We use analytic perturbation theory to present a new approximate metric for a rigidly rotating perfect fluid source with equation of state (EOS) $\epsilon +(1-n)p=\epsilon _0$ . This EOS includes the interesting cases of strange matter, constant density and the fluid of the Wahlquist metric. It is fully matched to its approximate asymptotically flat exterior using Lichnerowicz junction conditions and it is shown to be a totally general matching using Darmois–Israel conditions and properties of the harmonic coordinates. Then we analyse the Petrov type of the interior metric and show first that, in accordance with previous results, in the case corresponding to Wahlquist’s metric it can not be matched to the asymptotically flat exterior. Next, that this kind of interior can only be of Petrov types I, D or (in the static case) O and also that the non-static constant density case can only be of type I. Finally, we check that it can not be a source of Kerr’s metric.     

Boundary-induced Anderson localization in photonic lattices

We analyze numerically localization of light in linear square waveguide arrays restricted in one dimension (“ribbons”), whose boundaries are disordered in propagation constant and/or coupling. We find that the disordered boundary induces a localization tendency in the bulk even for relatively wide ribbons.     

Radiative open charm decay of the Y(3940) , Z(3930) , X(4160) resonances

We determine the radiative decay amplitudes for the decay into D^* and $ \bar{{D}}$ $ \gamma$ , or D ^* _s and $ \bar{{D}}_{s}^{}$ $ \gamma$ of some of the charmonium-like states classified as X , Y , Z resonances, plus some other hidden charm states which are dynamically generated from the interaction of vector mesons with charm. The mass distributions as a function of the $ \bar{{D}}$ $ \gamma$ or $ \bar{{D}}_{s}^{}$ $ \gamma$ invariant mass show a peculiar behavior as a consequence of the D ^* $ \bar{{D}}^{*}_{}$ nature of these states. The experimental search of these magnitudes can shed light on the nature of these states.     

Particle-yield modification in jetlike azimuthal dihadron correlations in Pb-Pb collisions at √s(NN)=2.76 TeV

The yield of charged particles associated with high-p(t) trigger particles (83 GeV/c on the away side drops to about 60% of that observed in pp collisions, while on the near side a moderate enhancement of 20%-30% is found.     

Relaxation of flexible chains in dilute and non‐dilute systems. Dynamic Monte Carlo results for linear and star chains

A dynamic Monte Carlo algorithm is employed to investigate the dynamics of flexible linear and star chains on a cubic lattice at different concentrations. Some results for similar systems are also obtained with an off‐lattice algorithm. Diffusion coefficient, relaxation times and mean size data are combined into friction‐independent ratios in good agreement with the theoretical predictions from the Rouse theory. The relaxation times and amplitudes corresponding to the Rouse normal modes are analyzed in terms of their variation with the mode order. The end‐to‐end vector correlation times obtained from the simulations for linear chains are compared with the theoretical expression obtained from the Rouse theory. Deviations from this theory are observed for the contribution of the different modes in the non‐dilute systems. Finally, the time correlation function corresponding to a subchain's end‐to‐end vector is investigated. The results also show deviations from the Rouse theory, which are in qualitative agreement with the features observed in data from dielectric relaxation experiments of block copolymers.     

Raman Spectra of Alkali and Alkaline Earth Metal Salts of Inosine 5′-Monophosphoric Acid

Crystalline Li(I), Na(I), K(I), Mg(II), Ca(II), Sr(II), Ba(II) and Cd(II) salts of inosine 5′-monophosphoric acid, H₂(IMP), were obtained and characterized by Raman spectroscopy. Splitting of the imidazolic 1480 cm⁻¹ band was observed for the N(7)-bound Ca(IMP)·6H₂O, Ba(IMP)·6H₂O, Sr(IMP)·6H₂O and Cd(IMP)·4H₂O compounds. The Li(I), Mg(II), Ca(II) and Cd(II) ions bind directly to the phosphate group, and no direct coordination involving the carbonyl C(6)O group was observed in the compounds reported here. Some Raman spectral features in the 750–700 cm⁻¹ range seem to reflect the nucleoside structure of the inosine moiety