Computer-Aided Search for 5-Arylideneimidazolone Anticancer Agents Able To Overcome ABCB1-Based Multidrug Resistance

ABCB1 modulation is an interesting strategy in the search for new anticancer agents that can overcome multidrug resistance (MDR). Hence, 17 new 5-arylideneimidazolones containing an amine moiety, as potential ABCB1 inhibitors, were designed, synthesized, and investigated. The series was tested in both parental (PAR) and multidrug-resistant (MDR) ABCB1-overexpressing T-lymphoma cancer cells using cytotoxicity assays. The ABCB1-modulating activity was examined in rhodamine 123 accumulation tests, followed by Pgp-Glo™ Assay to determine the influence of the most active compounds on ATPase activity. Lipophilic properties were assessed both, in silico and experimentally (RP-TLC). Pharmacophore-based molecular modelling toward ABCB1 modulation was performed. The studies allowed the identification of anticancer agents (p-fluorobenzylidene derivatives) more potent than doxorubicin, with highly selective action on MDR T-lymphoma cells (selectivity index >40). Most of the investigated compounds showed ABCB1-modulating action; in particular, two 5-benzyloxybenzylidene derivatives displayed activity nearly as strong as that of tariquidar.     

Investigation of some organic binders

These studies concern residues of the vacuum petroleum distillation of crude oil, used as binders for briquetting comminuted materials. The residues have been separated into the group components asphaltenes, resins, and oils. Chemical analyses of these components and calculations of some structural parameters by means of the Hazelwood and van Krevelen methods have been carried out on all these materials in order to indicate differences between the residues. The chemical constitutions of the binders examined do not differ basically but there are differences between some physical and rheological properties (viscosity, ductility), electrical properties (specific resistance, dielectric loss factor) and in molar refraction and in the carbon aromaticity (from volatile matter).     

Some aspects of the carbonization of vacuum distillation residue from crude oil

These studies concern the carbonization process of residues from vacuum distillation of crude oil. Some explanation aspects of the hypothetic reaction mechanism controlling the carbonization of high molecular weight components of crude oil are developed. On the basis of numerous experimental investigations, the thermal decomposition process can be divided into two stages, the first, from 670 to 790 K, in which the decomposition reactions take place and low and medium weight molecular compounds are emitted and the second stage, from above 790 K to 1000 K, in which cyclization, condensation and aromatization processes take place, and the degree of structural ordering in the solid products increases.     

Grafting of poly(acrylic acid) on polyamide yarn

Graft copolymerization of acrylic acid onto PA6 yarn was examined in this study. Prior to the grafting process, the fibers were activated with a benzene solution of benzoyl peroxide. Next, the fibers were put into a bath containing acrylic acid, a dispersing agent, and the activator of reaction. The effects of the main process parameters and auxiliary additives on the degree of grafting, quantity of the homopolymer formed during grafting, effectiveness of grafting, extent of conversion, and grafting ratio were determined. Using calculation factors such as the reaction efficiency, the extent of reaction, and the ratio of grafting, the conditions of grafting were found that made possible the reduction or elimination of the by‐product. Also determined were the influence of the degree of grafting on the moisture sorption and the swelling of modified fibers. In addition, the value of apparent activation energy was calculated (49.123 kJ/mol). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1914–1919, 2001     

Polyurethane/Polylactide-Based Electrospun Nonwovens as Carriers for Human Adipose-Derived Stromal Stem Cells and Chondrogenic Progenitor Cells

Articular cartilage dysfunctions are major cause of pain and disability and lead to serious health complications. Cell-based therapies are proposed as treatment methods for cartilage regeneration. In this study, we proposed polyurethane/poly(L-lactide-co-D, L-lactide)-based electrospun nonwovens as carriers for the delivery of human adipose-derived stromal stem cells. We found that 6:4 and 8:2 polyurethane/poly(L-lactide-co-D, L-lactide) initially enhance proliferative rate of human adipose-derived stromal stem cells, shorten their population doubling time, promote creation of functional chondrogenic nodules during chondrogenic differentiation, improve the collagen-2-to-collagen-1 protein ratio, and upregulate the expression of collagen-2 and aggrecan genes.     

1H-NMR spectroscopic investigation of polyamide fibers grafted with vinyl monomers

Nuclear magnetic resonance spectroscopy was used to investigate the position of active centers in polyamide fibers subjected to graft copolymerization with poly(acrylic acid), poly(itaconic acid), and poly(2-vinylpyridine) initiated by thermal oxidation in air. As a result, structural changes in polyamide fibers brought about by oxidation and subsequent grafting of the above mentioned polymers were observed. It was estimated that the generation of active centers that initiate the copolymerization take place at the nitrogen atoms of the amide groups in the polyamide chain. This was confirmed by the broadening of the absorption band for the methylone group adjacent to the nitrogen as well as by the absence of a new absorption band for the methine groups, assuming that the generation of active centers and grafting would take place at the carbon atom of the methylene group in position α to the amide group. © 1996 John Wiley & Sons, Inc.     

Drying Conditions and Processability of Dried Rapeseed

The possibility of using the oil-point and compression tests for evaluation of dried rapeseeds processability was examined. Seeds of initial moisture 10, 14, 18 and 22% (w/w) were dried at 60, 80, 100 and 120°C to a final moisture of 6·5% (w/w). The values of pressure ( P ₀ ), work ( L ₀ ) and strain (ε₀) determined by the oil-point test, and pressure at strain ε=0·45 mm mm⁻¹ ( P_ε ) and degree of elasticity ( D ) determined by the compression test for bulk dried seeds differed markedly from those found for non-dried seeds. The P ₀ , L ₀ and P_ε values were strongly correlated with the initial moisture of rapeseeds and drying temperature. All the strain values (ε₀) were lower than those for non-dried seeds, and their changes depended solely on the initial moisture of seeds. Changes in the degree of elasticity were irregular and did not reach the value characteristic for overdried seeds, ie 100%. High correlation of the agglomeration test data (Δ_1–3 values) with those of the P ₀ , L ₀ and P_ε made it possible to develop appropriate equations that proved the usefulness of the variables for determining the dried rapeseed processability.     

A Holistic Approach to Determining Stereochemistry of Potential Pharmaceuticals by Circular Dichroism with β-Lactams as Test Cases

This paper’s main objective is to show that many different factors must be considered when solving stereochemical problems to avoid misleading conclusions and obtain conclusive results from the analysis of spectroscopic properties. Particularly in determining the absolute configuration, the use of chiroptical methods is crucial, especially when other techniques, including X-ray crystallography, fail, are not applicable, or give inconclusive results. Based on various β-lactam derivatives as models, we show how to reliably determine their absolute configuration (AC) and preferred conformation from circular dichroism (CD) spectra. Comprehensive CD analysis, employing both approaches, i.e., traditional with their sector and helicity rules, and state-of-the-art supported by quantum chemistry (QC) calculations along with solvation models for both electronic (ECD) and vibrational (VCD) circular dichroism ranges, allows confident defining stereochemistry of the β-lactams studied. Based on an in-depth analysis of the results, we have shown that choosing a proper chiroptical method/s strictly depends on the specific case and certain structural features.