Collective mass parameters in the nuclear fission process

The theory of nuclear fission process is considered. The effective mass parameters are calculated as a function of the following collective coordinates: the separation between the centres of harmonic oscillators, the mass asymmetry parameter and the necking parameter. Numerical calculations are carried out for the fission of²³⁶U and²³⁸U nuclei. Symmetric and asymmetric cases are considered. From the present calculation we see the importance of taking into account the necking parameter as a dynamical collective coordinate.     

Mass Distributions and Charge Dispersion for the Nuclear Fission

The theory of nuclear fission is reconsidered by introducing the charge asymmetry in the asymmetric two center shell model as a dynamical collective coordinate. The quantum mechanical fluctuations, which are accompanied with the collective motion as a function of the mass asymmetry, are responsible for the mass distributions in nuclear fission. Numerical calculations are carried out for the mass distributions and charge dispersions for the nuclear fission of the ²³⁶U and ²³⁸U nuclei. The present obtained theoretical calculations are in good agreement with the experimental measurements.     

Three dimensional texture analysis in MRI: a preliminary evaluation in gliomas

The discrimination of tumor boundaries from normal tissue, as well as the evaluation of tissue heterogeneity and tumor grading often continue to pose a challenge in MRI. Although yielding promising results in various fields of medical imaging, two- dimensional (2D) texture analysis in MRI has, until now, demonstrated a lack of specificity in brain tumor classification. A new three-dimensional (3D) approach using Cooccurrence Matrix analysis is proposed to increase the sensitivity and specificity of brain tumor characterization. A preliminary comparative evaluation of 2D and 3D texture analysis was performed on T(1)-weighted MRI of seven gliomas for characterization of solid tumor, necrosis, edema and surrounding white matter. With 3D compared to 2D method, a better discrimination is obtained between necrosis and solid tumor as well as between edema and solid tumor. Using both methods, peritumoral white matter overlaps with edema, but is completely separated from far homo-lateral matter. This latter shows a complete overlapping with contra-lateral matter. The 3D texture analysis approach could provide a new tool for tumor grading and treatment follow-up, as well as for surgery or radiation therapy planning.     

Effect of electrolytes on the retention behavior of some benzenesulfonates in electrochemically modulated liquid chromatography

The effects of electrolytes on the retention behavior of some benzenesulfonates in electrochemically modulated liquid chromatography were studied. Both cations and anions were found to have considerable effects on retention. As cation size increases, retention decreases, while anions show more complicated effects were anionic size and charge distribution contribute to the overall behavior of anions. Large anions with a delocalized negative charge on the whole species result in lower retention times, and vice versa. Also, electrolyte concentration plays an important role in the retention behavior observed. Initially, as electrolyte concentration was increased retention increased due to electrostatic interactions of cations with the negatively charged stationary phase. However, retention starts to slightly decrease or increase after some specific electrolyte concentration depending on the nature of the electrolytic species. Finally, an interesting behavior of double peak appearance of a single solute was observed at low electrolyte concentrations and was attributed to the presence of other active sites on the carbon stationary phase.     

Chelation behaviour of nitroso- pyrazolones with Mn(II), Co(II), Ni(II), Cu(II) AND Zn(II)

Infrared (IR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TG), derivative thermogravimetric analysis (DTG), differential thermal analysis (DTA) and molar conductivity studies have been carried out on the chelates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with 3-methyl- and 3-phenyl-4-nitroso-5-pyrazolones. The solid chelates were synthesized, separated, analyzed and their structures were elucidated. The data obtained show that almost all of the prepared chelates contain water molecules in their coordination sphere. The initial stage in the thermal decomposition process of these chelates shows the presence of water molecule, the second denotes to the intermediate products. The final decomposition products were found to be the respective metal oxides. The NMR spectrum of 3-methyl-4-nitroso-5-pyrazolone ligand shows the existence of the oxime rather than the nitroso form. 3-phenyl-4-nitroso-5-pyrazolone acts as a neutral bidentate ligand whereas 3-methyl-4-nitroso-5-pyrazolone acts as monobasic bidentate ligand bonded to the metal ions through the two oxygen atoms of the carbonyl and nitroso groups. The solid chelates prepared behave as non-electrolytes in DMF solution. The coordination numbers of the obtained chelates using 3-methyl-4-nitroso-5-pyrazolone are four on applying the mole ratio 1:1 and six on using 1:2 mole ratio. In case of using the ligand 3-phenyl-4-nitroso-5-pyrazolone the coordination number is six in both cases. This revised version was published online in August 2006 with corrections to the Cover Date.     

Condensed 1,2,4-Triazines I: Behaviour of Phenanthro[9,10-e]-1,2,4-triazine Derivatives Towards Alkylating and Reducing Agends,Grignard Reagents,and Amines

Alkylation of 3-hydroxy-phenanthro[9,10-e]1,2,4-triazine ( 1a ) yielded the N(2)-alkyl derivatives 2a – 2b ; alkylation of the 3-mercapto analogue 1b yielded the S-alkyl derivatives 1f – 1i . 1a – 1b reacted with alkyl and aralkylmagnesium halides to yield the corresponding 3-hydroxy-, and 3-mercapto-5-alkyl-(aralkyl)-phenanthro[9,10-e]2,3,4,5-tetrahydro-1,2,4-triazines 5a – 5f . Reduction of 1a yielded the hexahydrotriazine derivative 7 . Amination of 1c yielded the 3-amino derivatives 1j – 1o after prolonged heating.     

Potentiometric,spectrometric, thermal and conductimetric studies on some 3-phenyl-4-(arylazo)-5-pyrazolones and their complexes with divalent cobalt metal ion

3-phenyl-4-arylazo-5-pyrazolones (I-IV) have been synthesized and characterized by elemental, infrared (IR), ultraviolet and visible spectra (UV-Vis), proton nuclear magnetic resonance (1H NMR) and Mass spectra. It has been proved that these compounds exhibit a keto-enol tautomerism in solution. The donor character of the substituent increases the enol form. The ionization constants of the investigated ligands have been determined potentiometrically and found to decrease in the order OCH(3)(IV)>CH(3)(III)>H(I)>Cl(II). The Co(II) complexes of the investigated 3-phenyl-4-arylazo-5-pyrazolones (I-IV) have been prepared and characterized by elemental and thermal analyses as well as by IR, UV-Vis, electronic transition, potentiometric, conductimetric and magnetic measurements. The data suggest octahedral geometry for Co(II) (1:1) complexes and tetrahedral for Co(II) (2:3) complexes.     

Spectrophotometric determination of enzymatically generated hydrogen peroxide using Sol-Gel immobilized horseradish peroxidase

Peroxidase entrapment in different Sol-Gel matrices was successful. The enzyme did not show a decrease in activity for at least 2 months as well as storage at room temperature and dry condition for periods exceeding 3 weeks. It was evident that the enzymatic activity was a function in the type of the alkoxysilane precursor. In addition, the optimum temperature which resulted in maximum enzymatic activity was also dependent on the type of Sol-Gel matrix. Excellent results were obtained for the determination of glucose in serum samples using soluble glucose oxidase in conjunction with the Sol-Gel entrapped peroxidase. The enzymatically produced hydrogen peroxide is oxidized by the entrapped peroxidase yielding oxygen which oxidizes the faint blue variamine blue into the intensely violet colored species (the molar absorptivity is about 1.8 x 10(4) 1 mol(-1) cm(-1)). The characteristics of this chromogenic system as well as optimized conditions for its use in the spectrophotometric determination of enzymatically generated hydrogen peroxide were investigated. Excellent agreement between the results obtained by the proposed method and the widely used standard method, utilizing a commercial reagents kit, was always observed.     

Two new cytotoxic furoquinoline alkaloids isolated from Aegle marmelos (Linn.) Correa

Two new cytotoxic furoquinoline alkaloids were isolated from the leaves of Aegle marmelos (Linn.) Correa; one from the total alkaloidal fraction (acid/base shake-out method) of the CHCl₃ extract and identified as 7,8-dihydroxy-4-hydrofuroquinoline and named trivially as Aegelbine-A. The other new alkaloid isolated from the pet. ether extract and identified as 4-hydro-7-hydroxy-8-prenyloxyfuroquinoline and named trivially as Aegelbine-B, together with a known alkaloid; aegeline and a known phenolic acid; ρ-hydroxybenzoic acid. The structures of all the isolated compounds were established based on 1D and 2D NMR spectroscopy and HR-ESI/MS. The cytotoxic activity of the isolated compounds was evaluated in vitro against HepG-2, PC3, A549 and MCF-7 cell lines. The obtained results revealed promising activity with structure-based relationship which is discussed briefly.     

Synthesis and Anticancer Activity of New Thiophene,Thiazolyl-Thiophene,and Thienopyridine Derivatives

Russian Journal of General Chemistry - New 4-acetyl-5-anilino-N-arylthiophene-2-carboxamide derivatives have been synthesized by reaction of 2-acetyl-3-oxo-N-phenylbutanethioamide with three...