Design of a composite ethidium-netropsin-anilinoacridine molecule for DNA recognition

Control of gene expression is a cherished goal of cancer chemotherapy. Small ligand molecules able to bind tightly to DNA in a well-defined configuration are being actively searched for. With this goal in mind, we have designed and synthesized the trifunctional molecule R-132, which combines a bispyrrole skeleton for minor groove DNA recognition and two different chromophores, anilinoacridine and ethidium. The affinity and mode of binding of R-132 to DNA were studied by a combination of complementary biochemical and biophysical techniques, which included absorption and fluorescence spectroscopy and circular and linear dichroism. A surface plasmon resonance biosensor analysis was also performed to quantify the kinetic parameters of the drug-DNA interaction process. Altogether, the results demonstrate that the three moieties of the hybrid molecule are engaged in the interaction process, thus validating the rational design strategy. At the biological level, R-132 stabilizes topoisomerase-II-DNA covalent complexes and displays potent cytotoxic activities, which are attributable to its DNA-binding properties. R-132 easily enters and accumulates in cell nuclei, as evidenced by confocal microscopy. R-132 therefore provides a novel lead compound for the design of gene-targeted anticancer agents.     

Dyeing of chrome tanned collagen modified by in situ grafting with 2‐EHA and MAC

The aim of this study deals with the modification of the chrome tanned collagen (leather) by in situ grafting with 2‐ethyl hexyl acrylate (2‐EHA) and methacrylic acid (MAC) to improve its dyeability using Amecid Floxine 2GN (C.I. Acid Red 1) and Remazol Black B (C.I. Reactive Black 5). The optimum condition of in situ grafting has been evaluated. FTIR spectra of the ungrafted and the in situ grafted chrome tanned collagen showed that the corresponding band of the acrylate carbonyl ester occurs at 1730–1735 cm^?1 when compared with the ungrafted ones. The colorimetric data of the in situ grafted and dyed samples exhibited improvement in color shade, dye bath exhaustion, wash and light fastness relative to the ungrafted and dyed ones. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 174–179, 2006     

Efficient numerical solution for highly transient flows

The numerical solutions for different formulations of the conservation equations based on the dependent variables, pressure (P), enthalpy (h), density (ρ), entropy (s) and flow velocity (u) for highly transient flows are presented. The models are each in turn applied for simulating the transient fluid flow dynamics following the rupture of a real and a number of hypothetical pipelines containing liquid, flashing liquid, two-phase and a permanent gas. In the case of the flashing liquid and two-phase pipelines, a significant reduction in the computational run time for the Phu and Psu based simulations as compared to the conventional Pρu formulation is observed. The above effect is found to be much less pronounced for the liquid and permanent gas inventories.     

The effect of gamma irradiation on the pressure dependence of the room temperature transition in PTFE

Some of the effect of gamma irradiation on the pneumatic pressure dependence of the well established room temperature transition (ca. 19 °C) in polytetra(fluoroethylene) are described. The experiments, conducted up to a maximum gamma dosage of 60 Mrad and a superimposed nitrogen pressure of 48.3 MPa indicate a significant reduction in the room temperature transition as well as its pressure dependence with the increasing of the gamma dosage. These data, combined with the observed and reported reduction in the free volume (actually net volume) are consistent with the proposition that irradiation process results in a reduction in the ‘effective internal pressure’ due to extensive bond scission. The latter process is manifested in an observed dramatic decrease in the molecular weight. Data on the compressibility and coefficient of thermal expansion, accompanied by thermodynamic arguments, indicate that the room temperature transition more closely resembles a second order transition as gamma dosage increases. This is consistent with a change in system behaviour progressing from a viscoelastic to that of a brittle glassy polymer as confirmed by monitoring the polymer creep behaviour following rapid pressurisation. Data for the ‘freshly’ irradiated specimens indicate highly transient post-irradiation induced changes in the polymer morphology.     

Fiber-Reinforced Plastic Jackets for Ductility Enhancement of Reinforced Concrete Bridge Columns with Poor Lap-Splice Detailing

This paper presents an inclusive testing program conducted on scaled models of reinforced concrete (RC) bridge columns with insufficient lap-splice length. Thirteen half-scale circular and square column samples were tested in flexure under lateral cyclic loading. Three columns were tested in the as-built configuration whereas ten samples were tested after being retrofitted with different composite-jacket systems. A brittle failure was observed in the as-built samples due to bond deterioration of the lap-spliced longitudinal reinforcement. The jacketed circular columns demonstrated a significant improvement in their cyclic performance. Yet, tests conducted on square jacketed columns showed a limited improvement in clamping on the lap-splice region and for enhancing the ductility of the column.     

Effect of natural polyphenols on physicochemical properties of crosslinked gelatin‐based polymeric biocomposite

This work was aimed to study the effect of natural polyphenols extract (Acacia nilotica bark) on physicochemical properties of crosslinked gelatin‐poly(acrylamide‐co‐acrylic acid), Gel‐poly(AAm‐co‐Ac), polymeric biocomposite film. Gelatin‐based composite films have extensive application as biocompatible biomaterial as drug carriers, cosmetics, and agricultural food packaging. The prepared composite films were characterized using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC), in addition to the swelling and degradation behavior. UV‐Vis absorption spectra and scanning electron microscopy (SEM) were also applied to observe the interaction between Gel‐poly(AAm‐co‐Ac) and natural polyphenol (catechin). The study has demonstrated that the involvement of hydrogen bonding and hydrophobic interactions as the major forces involved in the stabilization of gelatin‐based polymeric biocomposite film by the plant polyphenols (catechin and gallic acid derivatives). Thermal stability studies of crosslinked gelatin‐based composite film revealed that A. nilotica bark extract stabilizes the gelatin molecules and leads to moderate increase of the denaturation temperatures relative to the uncrosslinked one. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and Characterization of Novel Thermoplastic Films for Removal of Heavy Metal Ions

The main objective of this study is to establish the applicability of novel thermoplastic films based on extracted gelatins from bovine (G_b) and bird (G_c) bones in addition to hide powder (HP), which blended with modified polyethylene (MPE) for the removal of heavy metal ions such as copper (II), chromium (VI), nickel (II) and zinc (II) from aqueous media. The chemical reaction between 2-oxoglutaric acid with furfural in presence of methyl amine, via Mannich reaction mechanism, resulted in chemical compound I. The chemical structure of product I was confirmed by different spectroscopic tools such as: nuclear magnetic resonance (¹³C- and ¹H-NMR) and Fourier transform infrared spectroscopy (FT-IR). The synthesized chemical product I was used as compatibilizing agent for blending G_b, G_c and Hp with MPE to obtain thermoplastic films using a polymer melting technique. The efficiency of the prepared films for absorption of different heavy metal ions from aqueous solution was investigated. The results indicated that the compatibilized films (MPE/I/HP) illustrated a maximum removal of zinc metal ions (～100%) under conditions of initial metal concentration about 240 mg/l. While, at initial metal concentration of about 150 mg/l, they exhibited excellent efficiency for removal of mixed metal ions of about 97–100% relative to the uncompatibilized ones (MPE/HP) 0%.     

The Stimulation of Sandstone Reservoirs Using DC Potential

Abstract

The authors describe the effect of direct current application in conjunction with waterflood on improving flow properties of Berea sandstone cores. Single- and two-phase flow experiments are conducted on a specially designed coreflood setup, under constant electrode potential. The results showed that core permeability may increase up to 223% when hydraulic gradient and electroosmotic flow are applied in the same direction. The effect is insignificant when they work in opposite direction. It is verified from experimental results that dislodgement of clay in colloidal form, resulting increase of effective pore throat diameter improved hydraulic permeability.     

Courant, Friedrichs and Lewy (CFL) impact on numerical convergence of highly transient flows

This paper addresses the critically important issue regarding the appropriate size of the discretisation elements whilst ensuring stability and reasonable computational work loads for the numerical simulation of highly transient flows. The simulation of outflow following the puncture of a hypothetical 100 m pipeline at 21.6 bara (2160 kPa) and 293.15 K is used as a case example. The pipeline is assumed to contain different classes of hydrocarbons including permanent gases and liquids, two-phase mixtures and flashing liquids. The simulated outflow data for varying discretisation time and distance elements, expressed in terms of a Courant, Friedrichs and Lewy (CFL) factor indicate that in the case of permanent fluids and two-phase mixtures, a hyperbolic increase in the computational run time with decreasing CFL factor is obtained. There is no CFL factor dependency with the simulated outflow data. However in the case of flashing liquids and their mixtures, although similar trends in the computation run times are observed, the prescribed CFL stability condition at CFL factors of less than 0.4 does not result in convergence.