Alginate polyelecrtolyte ionotropic gels. Part IX: Diffusion control effects on the relaxation time of sol-gel transformation for transition-divalent metal alginate ionotropic gel complexes

Hassan, Refat M.; Makhlouf, M.Th.; El-Shatoury, S. A.

doi:10.1007/bf01095065

Cited by 26 publications

(26 citation statements)

References 12 publications

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“…The experimental conditions in this work consistently generated small ordered capillaries along the length of the gelled sample with copper and only generated limited large truncated capillaries in calcium. Such an effect is consistent with stronger binding by copper and increased gel strength relative to other metal ions 45. This stronger binding leads to the increased molecular dynamics during reaction shown in Figs 9 and 10 for the copper relative to the calcium system.…”

Section: Resultssupporting

confidence: 75%

“…The MR data clearly indicate a difference in the translational molecular dynamics due to the formation of the heterogeneous structures in the form of capillaries in the copper system which are absent in the calcium system under our experimental conditions. The formation of capillary structures is dependent on many parameters including metal ion concentration and type, solution pH, and alginate structure and concentration 5, 9, 45. The experimental conditions in this work consistently generated small ordered capillaries along the length of the gelled sample with copper and only generated limited large truncated capillaries in calcium.…”

Section: Resultsmentioning

confidence: 57%

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Binding of Topotecan to a Nicked DNA Oligomer in Solution

Bocian

Kawęcki

Bednarek

et al. 2008

Chemistry A European J

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Topotecan (TPT) is in clinical use as an antitumor agent. It acts by binding to the covalent complex formed between nicked DNA and topoisomerase I, and inserts itself into the single-strand nick, thereby inhibiting the religation of the nick and acting as a poison. A crystal structure analysis of the ternary complex has shown how the drug binds (B. L. Staker, K. Hjerrild, M. D. Feese, C. A. Behnke, A. B. Burgin, L. Stewart, Proc. Natl. Acad. Sci. U.S.A., 2002, 99, 15 387-15 392), but has left a number of unanswered questions. Herein, we use NMR spectroscopy and molecular modeling to show that the solution structure of a complex of TPT with nicked natural DNA is similar, but not identical to the crystal conformation, and that other geometries are of very low population. We also show that the lactone form of TPT binds approximately 40 times more strongly than the ring-opened carboxylate.

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Section: Resultssupporting

confidence: 75%

Section: Resultsmentioning

confidence: 57%

Binding of Topotecan to a Nicked DNA Oligomer in Solution

Bocian

Kawęcki

Bednarek

et al. 2008

Chemistry A European J

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“…Alginate is extracted from marine brown algae and is a biocompatible, nontoxic, nonimmunogenic, and biodegradable polysaccharide composed of -D-mannuronic and -L-guluronic acid. [62][63][64][65] The used sodium alginate (Manucol DM [G 39]) is a high-viscosity sodium alginate with a molecular weight ranging from 130 000 to 320 000 g/mol. This polymeric material has a quasicontinuous distribution of the molecular weight.…”

Section: Chemicalsmentioning

confidence: 99%

Surfactant‐mediated formation of alginate layers at the water‐air interface

Degen

Paulus

Zwar

et al. 2019

Surface & Interface Analysis

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The self‐organization process of polysaccharide alginate with different cationic surfactants at the water‐air interface was investigated over a wide concentration regime. The changes of surface properties determined by surface tension measurements, surface rheology, and X‐ray reflectivity are correlated with changes of bulk properties measured by turbidity, light scattering, and zeta potential measurements. We demonstrate that the interactions between the alginate and cationic surfactants result in significant changes of bulk and interfacial properties. The results of surface shear experiments point to the existence of highly viscoelastic interfacial films. In combination with X‐ray reflectivity, we demonstrate that these rheological features are related to polymer‐surfactant associations at the interface. In the regime of high surfactant concentrations, we observed the existence of multilayer structures.

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“…In view of the above arguments and our interest in physicochemical properties of macromolecules, in particularly the natural polymeric compounds [23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46], the present work was undertaken to shed more light on the role of the nature of medium and the structural geometry of the inhibitor on the corrosion process. The study also aimed to elucidate a suitable mechanism for corrosion of Al in acidic medium and discuss the results in comparison with previously reported studies on use of the natural polymer pectate polysaccharide as inhibitor for corrosion of Al in alkaline solutions [16].…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Corrosion Inhibition of Aluminum in Acidic Media by Water-Soluble Natural Polymeric Pectates as Anionic Polyelectrolyte Inhibitors

Hassan

Zaafarany

2013

Materials

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Corrosion inhibition of aluminum (Al) in hydrochloric acid by anionic polyeletrolyte pectates (PEC) as a water-soluble natural polymer polysaccharide has been studied using both gasometric and weight loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing inhibitor concentration and decrease with increasing temperature. The inhibition action of PEC on Al metal surface was found to obey the Freundlich isotherm. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the kinetic results is discussed in the paper.

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Alginate polyelecrtolyte ionotropic gels. Part IX: Diffusion control effects on the relaxation time of sol-gel transformation for transition-divalent metal alginate ionotropic gel complexes

Cited by 26 publications

References 12 publications

Binding of Topotecan to a Nicked DNA Oligomer in Solution

Binding of Topotecan to a Nicked DNA Oligomer in Solution

Surfactant‐mediated formation of alginate layers at the water‐air interface

Kinetics of Corrosion Inhibition of Aluminum in Acidic Media by Water-Soluble Natural Polymeric Pectates as Anionic Polyelectrolyte Inhibitors

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