Dinesh O. Shah

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Titration of a series of C(18) fatty acids yields pK(a) values that decrease with an increasing degree of unsaturation in the fatty acid chain. The pK(a) values of stearic, elaidic, oleic, linoleic, and linolenic acids were studied and compared to values of area per molecule in a spread monolayer of these acids. The decrease in pK(a) was found to relate to(More)
The orientation of surface-active molecules at interfaces is extremely important in determining the dynamic and equilibrium properties of such systems. Films of fatty acid salts were studied at various pH values of the solutions. It was found that there exists a pH where minimum evaporation of water, maximum foamability, maximum foam stability, minimum(More)
Microemulsions are excellent candidates as potential drug delivery systems because of their improved drug solubilization, long shelf life, and ease of preparation and administration. The formulation of microemulsions for pharmaceutical use requires a thorough understanding of the properties, uses, and limitations of microemulsions. Three distinct(More)
BACKGROUND Chagas disease is caused by Trypanosoma cruzi, a protozoan parasite that can be transmitted by transfusion. The diagnosis of chronic T. cruzi infection is generally made by detecting specific antibodies that bind to parasite antigens. The aim of this study was to assess the sensitivity and specificity of a new serologic assay for antibodies to T.(More)
The association of many classes of surface-active molecules into micellar aggregates is a well-known phenomenon. Micelles are in dynamic equilibrium, constantly disintegrating and reforming. This relaxation process is characterized by the slow micellar relaxation time constant, tau(2), which is directly related to the micellar stability. Theories of the(More)
The association of poliovirus with membrane filters results from both electrostatic and hydrophobic interactions. At low pH, electrostatic interactions appear to dominate. However, at high pH, hydrophobic interactions appear to dominate with both Millipore and Zeta plus filters. With both filters, viral elution was prevented at high pH by the presence of(More)
Aquantitative structure-property relationship studywasperformedon the criticalmicelle concentration (cmc) of nonionic surfactants using the CODESSA program. A known correlation between the logarithm of the cmc and counts of linear alkane carbon atoms and ethoxy groups in linear alkyl ethoxylates was improved (R2 ) 0.996) by adding cross terms of these(More)
We present a methodology to quantitatively determine the fraction of sodium dodecyl sulfate (SDS) that partitions to the oil/water interface in oil-in-water macroemulsions and calculate the total interfacial area (TIA) through the novel use of filtration through nanoporous membranes. Ultrafiltration was carried out in centrifuge tubes having nanoporous(More)
It is well-known that certain mixtures of surfactants can provide better performance than pure surfactants for a wide variety of applications,1,2 and thus it is expected that enhanced solubilization ofwater inwater-in-oil (w/o) microemulsions will also be achieved with certain surfactant mixtures. The formation of w/o microemulsions involves dissolving an(More)