Body waves in fractured porous media saturated by two immiscible newtonian fluids

A study of body waves in fractured porous media saturated by two fluids is presented. We show the existence of four compressional and one rotational waves. The first and third compressional waves are analogous to the fast and slow compressional waves in Biot's theory. The second compressional wave arises because of fractures, whereas the fourth compressional wave is associated with the pressure difference between the fluid phases in the porous blocks. The effects of fractures on the phase velocity and attenuation coefficient of body waves are numerically investigated for a fractured sandstone saturated by air and water phases. All compressional waves except the first compressional wave are diffusive-type waves, i.e., highly attenuated and do not exist at low frequencies.Now at Izmir Institute of Technology, Faculty of Engineering, Gaziosmanpasa Bulvari, No.16, Cankaya, Izmir, Turkey.     

Synthesis of the azocino[4,3‐b]indole core structure for the synthesis of strychnos alkaloids

The synthesis of compound 12 which has a hexahydro‐1,5‐methanoazocino[4,3‐b]indole structure for the synthesis of pentacyclic strychnos type alkaloids (tubifolin and tubifolidine) is described. Many new compounds 5–12 have also been synthesized.     

Bianchi transformation between the real hyperbolic Monge-Ampère equation and the Born-Infeld equation

By casting the Born-Infeld equation and the real hyperbolic Monge-Ampère equation into the form of equations of hydrodynamic type, we find that there exists an explicit transformation between them. This is Bianchi transformation.     

Ricci collineations of the Bianchi type II,VIII, and IX space-times

Ricci and contracted Ricci collineations of the Bianchi type II, VIII, and IX space-times, associated with the vector fields of the form (i) one component of ^a (x ^b ) is different from zero and (ii) two components of ^a (x ^b ) are different from zero, fora, b=1, 2, 3, 4, are presented. In subcase (i.b), which is ^a = (0, ¹(x ^a ),0,0), some known solutions are found, and in subcase (i.d), which is ^a =(0, 0, 0, ⁴(x ^a )), choosingS(t) = const.×R(t), the Bianchi type II, VIII, and IX spacetime is reduced to the Robertson-Walker metric.     

A novel synthetic approach for the synthesis of pyridocarbazole alkaloids

The synthesis of 11‐methyl‐6H‐pyrido[4,3‐b]carbazole‐1(2H)‐one (5), which can be important for the synthesis of other pyridocarbazole alkaloids and especially 1‐substituted ellipticines, is described. Construction of the tetracyclic structure was achieved by a new route and two important precursor compounds (4a and 4b) for the synthesis of pyridocarbazole alkaloids and also many new tetrahydrocar‐bazole derivatives (7, 8, 9, 10, 11, 12, 13) were synthesized.     

Concanavalin a immobilized affinity adsorbents for reversible use in yeast invertase adsorption

Concanavalin A (Con A) immobilized poly(2-hydroxyethyl methacrylate) (PHEMA) beads were investigated for specific adsorption of yeast invertase from aqueous solutions. PHEMA beads were prepared by a suspension polymerization technique with an average size of 150-200 microm, and activated by epichlorohydrin. Con A was then immobilized by covalent binding onto these beads. The maximum Con A immobilization was found to be 10 mg/g. The invertase-loading capability of the PHEMA/Con A beads was 107 mg/g. The maximum invertase adsorption capacity on the PHEMA/Con A adsorbents was observed at pH 5.0. The values of the Michaelis constant K(m) of invertase were significantly larger upon adsorption, indicating decreased affinity by the enzyme for its substrate, whereas V(max) was smaller for the adsorbed invertase. Adsorption improved the pH stability of the enzyme as well as its temperature stability. Thermal stability was found to increase with adsorption. The adsorbed enzyme activity was found to be quite stable in repeated experiments. Storage stability of adsorbed invertase.     

Reactions of 1S, 1D,and 3P carbon atoms with water. Oxygen abstraction and intermolecular formaldehyde generation mechanisms; An MCSCF study

Reactions of singlet and triplet carbon atoms with water are explored theoretically using CASSCF–MCQDPT2, CCSD, and DFT methodologies. The ¹S carbons are found to be unreactive. Depending on the carbon atom generation method and the reaction medium, gas‐phase C(³P) attacking water may generate CO and atomic hydrogen as the end products. Reaction paths of the C(¹D) + H₂O system are complicated due to the involvement of two reactive potential energy surfaces with branchings occurring along each. Modifications in product distributions for reactions taking place in condensed phases are elaborated. The decisive reaction conditions, under which the oxygen abstraction and intermolecular formaldehyde generation dominate, are suggested to clarify the discrepancy related with experimental CO observation. The findings are consistent with available experimental data on this system. Oxygen abstraction and intermolecular formaldehyde generation mechanisms suggested here are capable of serving as models for similar reactions of alcohols. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

The cytotoxic activities of imidazole derivatives prepared from various guanylhydrazone and phenylglyoxal monohydrate

Abstract

A series of imidazole derivatives were synthesized from two-component condensation reaction of phenylgloxal monohydrate with guanylhydrazone. They were characterized by spectroscopic and analytical techniques. The in vitro anticancer evaluation of these compounds was done on human breast cancer (MCF-7) and human liver cancer (HepG2) cell lines using the MTT assay method. Most of the newly synthesized compounds displayed cytotoxic activity against these cancerous cells. In fact, compounds 3a, 3e, and 3?h exhibited more cytotoxic activities than the positive control drugs, fluro-5, and irinocam, against the MCF-7 cell line. Almost all the compounds, except for three, 3b, 3d, and 3f, gave more cytotoxic results than cisplatin. Therefore, these compounds could be considered for further development as anticancer drug candidates.     

Facile Method for 1,3‐Dipolar Cycloaddition Reaction of Azomethine Ylides: Highly Stereoselective Synthesis of Substituted Pyrrolidine Derivatives

The substituted pyrolidine derivatives with high stereoselectivity were obtained through cycloaddition reaction in the presence of a Lewis acid namely diethylzinc by solvent‐free grinding method.