Cevdet Akbay

Monomeric and polymeric anionic gemini surfactants and mixed surfactant systems in micellar electrokinetic chromatography. Part II: Characterization of chemical selectivity using two linear solvation energy relationship models Sodium di(undecenyl) tartarate monomer (SDUT), a vesicle-forming amphiphilic compound possessing two hydrophilic carboxylate headgroups and two hydrophobic undecenyl chains, was prepared and polymerized to form a polymeric vesicle (i.e., poly-SDUT). The anionic surfactants of SDUTand poly-SDUT (carboxylate head group) and sodium dodecyl sulfate, SDS (sulfate head groups) as well as mixed surfactant systems (SDS/SDUT, SDS/poly-SDUT, and SDUT/poly-SDUT) were applied as pseudostationary phases in micellar electrokinetic chromatography (MEKC). Two linear solvation energy relationship (LSER) models, i.e., solvatochromic and solvation parameter models, were successfully applied to investigate the effect of the type and composition of pseudostationary phases on the retention mechanism and selectivity in MEKC. The solvatochromic and solvation parameter models were used to help understand the fundamental nature of the solute-pseudostationary phase interactions and to characterize the properties of the pseudostationary phases (e.g., solute size and hydrogen bond-accepting ability for all pseudostationary phases). The solute types were found to have a significant effect on the LSER system coefficients and on the predicted retention factors. Although both LSER models provide the same information, the solvation parameter model is found to provide much better results both statistically and chemically than the solvatochromic model

Overtaking CPU DBMSes with a GPU in whole-query analytic processing with parallelism-friendly execution plan optimization

Existing work on accelerating analytic DB query processing with (discrete) GPUs fails to fully realize their potential for speedup through parallelism: Published results do not achieve significant speedup over more performant CPU-only DBMSes when processing complete queries. This paper presents a successful

Towards a Critical Global Citizenship?: A Comparative Analysis of GC Education Discourses in Scotland and Alberta

Global citizenship has increasingly become common parlance in education curricula internationally. Yet, it can be argued that in many instances, especially in official curriculum documents, Global Citizenship Education (GCE) tends to ignore critical engagement with ethics and complexity that inform global inequities worldwide, and often fails to achieve the self-reflective political consciousness called forth by a critical GCE. In this paper, we compare conceptualizations of GCE in the Alberta Social Studies curriculum, Canada, and in the Scottish national curriculum, Curriculum for Excellence. We consider the extent to which these documents and attending discourses open up critical discursive spaces for complex, ethical understandings and calls to action related to global injustices and political responsibilities, or foreclose important opportunities

Anticancer activity of Nigella sativa (black seed) and its relationship with the thermal processing and quinone composition of the seed

Riad Agbaria, Adi Gabarin, Arik Dahan, Shimon Ben-Shabat Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel Abstract: The traditional preparation process of Nigella sativa (NS) oil starts with roasting of the seeds, an allegedly unnecessary step that was never skipped. The aims of this study were to investigate the role and boundaries of thermal processing of NS seeds in the preparation of therapeutic extracts and to elucidate the underlying mechanism. NS extracts obtained by various seed thermal processing methods were investigated in vitro for their antiproliferative activity in mouse colon carcinoma (MC38) cells and for their thymoquinone content. The effect of the different methods of thermal processing on the ability of the obtained NS oil to inhibit the nuclear factor kappa B (NF-κB) pathway was then investigated in Hodgkin’s lymphoma (L428) cells. The different thermal processing protocols yielded three distinct patterns: heating the NS seeds to 50°C, 100°C, or 150°C produced oil with a strong ability to inhibit tumor cell growth; no heating or heating to 25°C had a mild antiproliferative effect; and heating to 200°C or 250°C had no effect. Similar patterns were obtained for the thymoquinone content of the corresponding oils, which showed an excellent correlation with the antiproliferative data. It is proposed that there is an oxidative transition mechanism between quinones after controlled thermal processing of the seeds. While NS oil from heated seeds delayed the expression of NF-κB transcription, non-heated seeds resulted in only 50% inhibition. The data indicate that controlled thermal processing of NS seeds (at 50°C–150°C) produces significantly higher anticancer activity associated with a higher thymoquinone oil content, and inhibits the NF-κB signaling pathway. Keywords: Nigella sativa, thermal processing, antiproliferative effect, thymoquinone, NF-κ

Complexation studies of water-soluble calixarenes and auramine O dye

The dye, Auramine O, whose fluorescence is sensitive to its microenvironment, is used to study the complexation properties of the host molecules, calix[6]arene sulfonates. Complexation between the dye and the sulfonated calixarenes has been characterized by use of absorption and steady state fluorescence measurements. A comparison study of the calixarenes and the monomers suggests that the observed shifts of the absorption and the fluorescence of Auramine O are due to complex formation. In addition, the fluorescence of Auramine O is enhanced as a result of its association with calixarenes. Fluorescence intensities in the absence and presence of calixarenes are employed to calculate formation constants of the inclusion complexes. The stoichiometric ratio for both SCX6/AuO and SCXO-C5H11/AuO is 1:1. The formation constants for these complexes are estimated to be 1.24 × 104 M-1 and 1.53 × 104 M-1, respectively

Spectroscopic analysis of the binding of doxorubicin to human α-1 acid glycoprotein

The binding of the anticancer drug doxorubicin (DOX) to human α-1 acid glycoprotein (AGP) is investigated using absorbance and fluorescence spectroscopies. Steady-state fluorescence and UV-vis absorbance measurements produced evidence of the formation of a 1:1 complex between DOX and AGP. Scatchard analysis indicated the presence of one major binding site for the drug on the protein, and estimated complex formation constants using both spectroscopic methods ranged from 104 to 105 M-1. Fluorescence lifetime and polarization measurements provided further evidence of complexation and indicated a loose binding of DOX to its binding site on AGP. Stern-Volmer fluorescence quenching analysis showed reduced accessibility of bound DOX to an anionic quencher, suggesting that the binding site for DOX on AGP is hydrophobic in nature. © 1993 American Chemical Society

Monomeric and polymeric anionic gemini surfactants and mixed surfactant systems in micellar electrokinetic chromatography. Part II: Characterization of chemical selectivity using two linear solvation energy relationship models

Sodium di(undecenyl) tartarate monomer (SDUT), a vesicle-forming amphiphilic compound possessing two hydrophilic carboxylate headgroups and two hydrophobic undecenyl chains, was prepared and polymerized to form a polymeric vesicle (i.e., poly-SDUT). The anionic surfactants of SDUT and poly-SDUT (carboxylate head group) and sodium dodecyl sulfate, SDS (sulfate head groups) as well as mixed surfactant systems (SDS/SDUT, SDS/poly-SDUT, and SDUT/poly-SDUT) were applied as pseudostationary phases in micellar electrokinetic chromatography (MEKC). Two linear solvation energy relationship (LSER) models, i.e., solvatochromic and solvation parameter models, were successfully applied to investigate the effect of the type and composition of pseudostationary phases on the retention mechanism and selectivity in MEKC. The solvatochromic and solvation parameter models were used to help understand the fundamental nature of the solute-pseudostationary phase interactions and to characterize the properties of the pseudostationary phases (e.g., solute size and hydrogen bond-accepting ability for all pseudostationary phases). The solute types were found to have a significant effect on the LSER system coefficients and on the predicted retention factors. Although both LSER models provide the same information, the solvation parameter model is found to provide much better results both statistically and chemically than the solvatochromic model. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim