Synthesis and Antitumor Evaluation of Some New Fused and Binary Pyridines

Syntheses of some new heterocyclic compounds containing pyridone, thioxopyridine, halogenated‐pyridine‐carbonitriles, pyrazolopyridine, and pyridine derivatives were achieved. Besides, a modified synthetic method for the synthesis of 2‐chloro‐4,6‐dimethyl‐nicotinonitrile ( 3 ) through the reaction of acetylacetone and malononitrile as starting materials was implemented. The reaction of 2‐chloronicotinonitrile 3 with substituted amines to 2‐aminonicotinonitrile were also investigated. Fused or binary pyridines were tested for cytotoxicity against well‐known established model Ehrlich ascites cells in vitro. Compound 13 exhibited a high antitumor activity compared with 5‐fluorouracil.     

IMPROVEMENT OF THE SEMI-ANALYTICAL METHOD, FOR DETERMINING THE GEOMETRICALLY NON-LINEAR RESPONSE OF THIN STRAIGHT STRUCTURES: PART II—FIRST AND SECOND NON-LINEAR MODE SHAPES OF FULLY CLAMPED RECTANGULAR PLATES

In a previous series of papers, a semi-analytical model based on Hamilton's principle and spectral analysis has been developed for geometrically non-linear free vibrations occurring at large displacement amplitudes of clamped-clamped beams and fully clamped rectangular homogeneous and composite plates. In Part I of this series of papers, concerned with geometrically non-linear free and forced vibrations of various beams, a practical simple “multi-mode theory”, based on the linearization of the non-linear algebraic equations, written in the modal basis, in the neighbourhood of each resonance has been developed. Simple explicit formulae, ready and easy to use for analytical or engineering purposes have been derived, which allows direct calculation of the basic function contributions to the first three non-linear mode shapes of the beams considered. Also, various possible truncations of the series expansion defining the first non-linear mode shape have been considered and compared with the complete solution, which showed that an increasing number of basic functions has to be used, corresponding to increasingly sized intervals of vibration amplitudes; starting from use of only one function, i.e., the first linear mode shape, corresponding to very small amplitudes, for which the linear theory is still valid, and ending by the complete series, involving six functions, corresponding to maximum vibration amplitudes at the beam middle point up to once the beam thickness. For higher amplitudes, a complementary second formulation has been developed, leading to reproduction of the known results via the solution of reduced linear systems of five equations and five unknowns. The purpose of this paper is to extend and adapt the approach described above to the geometrically non-linear free vibration of fully clamped rectangular plates in order to allow direct and easy calculation of the first, second and higher non-linear fully clamped rectangular plate mode shapes, with their associated non-linear frequencies and non-linear bending stress patterns. Also, numerical results corresponding to the first and second non-linear modes shapes of fully clamped rectangular plates with an aspect ratio α=0·6 are presented. Data concerning the higher non-linear modes, the aspect ratio effect, and the forced vibration case will be presented later.     

On the Spectrum of a Class of Strongly Coupled p-Laplacian Systems

Consider the nonlinear coupled elliptic system     

The absorption spectrum of 12C2H2 IV. The regions 7600–9200 cm−1 and 10600–11500 cm−1

The absorption spectrum of ¹²C₂H₂ has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10600–11 500 cm^?1 spectral region, where no absorption bands were previously reported. Fifteen bands starting from the vibrational ground state are observed and rotationally analysed. All corresponding excited vibrational levels were assigned using the polyad model, the so-called cluster model (El Idrissi, M.I., Liévin, J., Campargue, A., and Herman, M., 1999, J. chem. Phys., 110, 2074) which allows vibrational energies, rotational B_v constants and, to some respect, relative band intensities to be predicted. Additional data and constants are also provided in the range 7600–9200cm^?1, whenever improving the literature results, from spectra recorded previously at ULB using Fourier transform spectroscopy. The assignment procedure in the range recorded by ICLAS is detailed, leading to a deeper understanding of vibration-rotation and intensity features of the absorption bands within the frame of the cluster model.     

Stability-Indicating Spectrofluorimetric Method for Determination of Itopride Hydrochloride in Raw Material and Pharmaceutical Formulations

A simple, sensitive and rapid spectrofluorimetric method for determination of itopride hydrochloride in raw material and tablets has been developed. The proposed method is based on the measurement of the native fluorescence of the drug in water at 363 nm after excitation at 255 nm. The relative fluorescence intensity-concentration plot was rectilinear over the range of 0.1–2 μg/mL (2.5?×?10^?7–5.06?×?10^?6 mole/L), with good correlation (r?=?0.9999), limit of detection of 0.015 μg/mL and a lower limit of quantification of 0.045 μg/mL. The described method was successfully applied for the determination of itopride hydrochloride in its commercial tablets with average percentage recovery of 100.11?±?0.32 without interference from common excipients. Additionally, the proposed method can be applied for determination of itopride in combined tablets with rabeprazole or pantoprazole without prior separation. The method was extended to stability study of itopride. The drug was exposed to acidic, alkaline, oxidative and photolytic degradation according to ICH guidelines. Moreover, the method was utilized to investigate the kinetics of the alkaline, acidic and oxidative degradation of the drug. A proposal for the degradation pathways was postulated.     

Optical investigations on the existence of phase transition in ZnO:Li thin films prepared by DC sputtering method

We investigated the effect of temperature on the absorption spectra of Zn_0.8Li_0.2O thin films (ZnO:Li), deposited at 573 K, in the wavelength range 190‐800 nm. The films were deposited on sapphire, MgO or quartz substrates by DC sputtering method. The results show a shift of the optical energy gap (E_g), with direct allowed transition type near the fundamental edge, to lower wavelengths as the temperature increases. The temperature rate of E_g changes considerably showing an anomaly around 320 K depending on type of substrate. The founded results indicated that replacement of Zn ions with Li ions induces a ferroelectric phase in the ZnO wurtzite‐type semiconductor. The exponential dependence of the absorption coefficient on the incident photon energy suggests the validity of the Urbach rule. (© 2007 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Mass spectrometric identification of Rab23 phosphorylation as a response to challenge by cytidine 3',5'-cyclic monophosphate in mouse brain

While the functions and mechanisms of action of adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) are well established and are the basis of the action of a large number of successful pharmaceuticals, the role of a third naturally occurring cyclic nucleotide, cytidine 3',5'-cyclic monophosphate (cCMP), remains to be elucidated. Immobilized metal affinity chromatography (IMAC) was used to selectively extract proteins phosphorylated in mouse brain in response to challenge by cAMP, cGMP and cCMP, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToFMS) and liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) of tryptic digests to identify Rab23 as the first protein reported to be phosphorylated only in response to cCMP.     

Solubility and Thermodynamic Properties of Dipotassium or Disodium Hydrogenphosphates in Aqueous Solutions at Various Temperatures

Journal of Solution Chemistry - In this investigation, calculated and experimental solubilities of the binary aqueous solutions of dipotassium hydrogenphosphate and disodium hydrogenphosphate have...     

The absorption spectrum of 12C2D2 in the 10000–12500 cm−1 spectral region

The absorption spectrum of dideuteroacetylene has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10 200–12 500cm^?1 spectral region. Among 25 absorption bands of ¹²C₂D₂ rotationally analysed in this spectral region, 17 are newly observed. They include one II_u-Σ⁺ _g and thirteen Σ⁺ _u-Σ⁺ _g bands starting from the vibrational ground state and eleven hot bands from the V ₄ = 1 and V ₅ = 1 lower states. The rotational structure of two excited levels is affected by a strongly J-dependent interaction with a perturber which induces intensity transfer to extra lines. The coupling is identified as a I-resonance interaction with δ_u dark states and the vibrational assignment of the perturbers is discussed. Two Σ-Σ bands of the ¹²C¹³ CD₂ species, present in natural abundance in the sample, could also be identified and rotationally analysed. Most of the corresponding excited vibrational levels of ¹²C₂D₂ were unambiguously assigned using the polyad model [Herman, M., el idrissi, M. I., Pisarchik, A., Campargue, A., Gaillot, A.-C., Biennier, L., di lonardo, G. and Fusina, L., 1998, J. chem. Phys., 108, 1377] which allows vibrational energies and B _V rotational constants to be predicted. In particular the previously highlighted 1/244 anharmonic resonance is confirmed by energy and intensity features in several {(V ₁, V ₂, V ₃, V ₄ = 0, V ₅ = 0),(V ₁ ?1, V ₂ + 1, V ₃ V ₄ = 2, V ₅ = 0)} dyads. Significant deviations between predicted and experimental energy levels are observed for a few levels and discussed.     

The Iwasawa invariant $$\mu$$ μ vanishes for $$\mathbb{Z}_{2}$$ Z 2 -extensions of certain real biquadratic fields

Acta Mathematica Hungarica - For a real biquadratic field, we denote by $$\lambda$$ , $$\mu$$ and $$\nu$$ the Iwasawa invariants of cyclotomic $$\mathbb{Z}_{2}$$ -extension of $$k$$ . We give...