Synergistic Antiproliferative Effects of γ-Tocotrienol and Statin Treatment on Mammary Tumor Cells

Statins are potent inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMGCoA) reductase and display anticancer activity, but their clinical use is limited by their high-dose toxicity. Similarly, γ-tocotrienol, an isoform of vitamin E, also reduces HMGCoA reductase activity and displays potent anticancer activity. Studies were conducted to determine if combined low dose treatment of γ-tocotrienol with individual statins resulted in a synergistic antiproliferative effect on neoplastic mouse +SA mammary epithelial cells. Treatment with 3–4 μM γ-tocotrienol or 2–8 μM simvastatin, lovastatin or mevastatin alone resulted in a significant decrease, whereas treatment with 10–100 μM pravastatin had no effect on +SA cell growth. However, combined treatment of subeffective doses (0.25 or 10 μM) of individual statins with 0.25–2.0 μM γ-tocotrienol resulted in a dose-responsive synergistic inhibition in +SA cell proliferation. Additional studies showed that treatment with subeffective doses of individual statins or γ-tocotrienol alone had no effect, whereas combined treatment of these compounds resulted in a relatively large decrease in intracellular levels of phosphorylated (activated) MAPK, JNK, p38, and Akt. These findings strongly suggest that combined low dose treatment of γ-tocotrienol with individual statins may have potential value in the treatment of breast cancer without causing myotoxicity that is associated with high dose statin treatment.     

Physico-Chemical Investigations of Mixed Micelles of Cationic Gemini and Conventional Surfactants: a Conductometric Study

The interaction of cationic gemini and cationic conventional surfactants by conductivity was systematically overviewed, paying attention to synergism observed in micellization. These mixed systems were found to show remarkable synergism in micelle formation. The experimental critical micelle concentration values being lower than the value predicted by ideal solution theory indicate that the mixed micellization is due to attractive interaction between the two components. Gemini/conventional systems form mixed micelle due to attractive interactions (negative β values). The values of micellar mole fraction of constituent 1 (X ₁) in surfactant mixtures are more than in the ideal state (X ₁ ^ideal ), which means that, the mixed micelles are rich in conventional surfactants in comparison to that in the ideal state.     

Synergistic Effect of Mixed Surfactant Systems on Foam Behavior and Surface Tension

Foam and surface tension behaviors of different ionic/nonionic surfactant solutions along with their different combinations have been investigated. Among different surfactants, sodium dodecyl sulfate showed the highest foamability over other surfactants. Mixed surfactant systems were always found to have higher foamability than the individual surfactant. It was also noticeable that nonionic surfactants show good foamability when they combine with anionic and cationic surfactants. In the case of mixed surfactant systems, nonionic/cationic surfactant mixtures showed lower surface tension than nonionic/anionic surfactant mixture due to a synergistic effect.     

Role of epoxy functionality in microstructure–property relationships within elastomeric nanocomposites

Abstract

The contribution of epoxy functionalities in hybrid filler microstructures and interfaces within different binary and ternary particulate elastomeric nanocomposites, prepared by open two-roll mixing, was analysed. The epoxy percentages of the elastomeric phase were varied at three different levels (e.g. 0, 25 and 50%). Among the ternary samples, the most uniform distribution and dispersion were achieved in the case of the sample based on ENR-25 (epoxidised natural rubber matrix having 25 mol-% of epoxy group), as observed by small angle X-ray scattering (interfacial roughness) and transmission electron microscopy. Clay and carbon black jointly form hybrid microstructures like ‘nanounit’. Uniform distributions of such morphologies are reflected in tensile strength, elongation at break and half height width of the tan?δ peak. Although the cross-link density improves as the epoxy percentage is increased, the level of synergism between two different fillers in terms of cross-linking density gradually reduces with the increased epoxy percentages. Except for solely clay filled samples, the thermal stability enhances as the epoxy percentage is increased.     

Investigating synergism during sequential inactivation of MS-2 phage and Bacillus subtilis spores with UV/H2O2 followed by free chlorine

A sequential application of UV as a primary disinfectant with and without H₂O₂ addition followed by free chlorine as secondary, residual disinfectant was performed to evaluate the synergistic inactivation of selected indicator microorganisms, MS-2 bacteriophage and Bacillus subtilis spores. No synergism was observed when the UV irradiation treatment was followed by free chlorine, i.e., the overall level of inactivation was the same as the sum of the inactivation levels achieved by each disinfection step. With the addition of H₂O₂ in the primary UV disinfection step, however, enhanced microbial inactivation was observed. The synergism was observed in two folds manners: (1) additional inactivation achieved by hydroxyl radicals generated from the photolysis of H₂O₂ in the primary UV disinfection step, and (2) damage to microorganisms in the primary step which facilitated the subsequent chlorine inactivation. Addition of H₂O₂ in the primary disinfection step was also found to be beneficial for the degradation of selected model organic pollutants including bisphenol-A (endocrine disruptor), geosmin (taste and odor causing compound) and 2,4-D (herbicide). The results suggest that the efficiency of UV/free chlorine sequential disinfection processes, which are widely employed in drinking water treatment, could be significantly enhanced by adding H₂O₂ in the primary step and hence converting the UV process to an advanced oxidation process.     

Mixed Micellization Study of Alkyltrimethylammonium and Alkyltriphenylphosphonium Bromides in Aqueous Solution

Mixed micellization study of cationic surfactants viz. alkyltrimethylammonium bromides (C_nTAB) and alkyltriphenylphosphonium bromides (C_nTPPB) with similar hydrophobic groups (C₁₂-, C₁₄-, and C₁₆-) was performed using tensiometry and UV–visible light spectrophotometry techniques. Critical micelle concentration (CMC) values of the single and binary surfactant mixtures were obtained from a plot of surface tension versus the logarithm of surfactant concentration (C _s). The degree of synergy and various mixed micelle parameters like interaction parameter (β), activity coefficients (f ^m ) and interfacial parameters like surface pressure (π _CMC), packing parameter (P), surface excess concentration (Г _max), surface tension at the CMC (γ _CMC), and minimum area per molecule (A _min) were evaluated using the regular solution theory (RST). Thermodynamic parameters were calculated using several proposed models which suggest the mixed micellar system to be more thermodynamically stable than their respective individual components. In addition, a dye solubilization study was performed using a spectrophotometric method to validate the CMC data obtained from tensiometric method. Conductometric measurements were also carried out for the mixture of C₁₂TAB + C₁₂TPPB only as it showed a more negative β, indicating a higher degree of synergism.     

Antioxidative and synergistic effects of bene kernel and hull oils during oxidation of virgin olive oil

Total amounts of conjugated diene hydroperoxides and carbonyl compounds of a virgin olive oil (VOO) and its purified form as affected by 0.1–6% w/w bene kernel (BKO) and hull (BHO) oils were monitored during 16 h heating at 180°C. The VOO was more prone to the production of off‐flavour carbonyl compounds than to the formation of conjugated diene hydroperoxides. The VOOs oxidative stability decreased significantly due to the removal of the indigenous antioxidative compounds. Oxidative stability, especially regarding the secondary oxidation, significantly improved with increasing concentrations of the BKO than with those of the BHO.     

Combustion Study of Synergism of Urea-Sodium Polymetaphosphate on the Flame-Retardancy of a Cotton Fabric Monitored by TG

The synergism of sodium polymetaphosphate- urea on the flammability of a cotton fabric (woven, plain 144 g/m², the number of yarns 21 per 10 mm) has been investigated in this study. After impregnation with suitable individual additives and/or their appropriate admixed formulation onto the fabrics, their flammability has been assessed by using the described procedure. In this study the flame spread tests comply with thermogravimetry's data. Explanation of the synergism with regard to the thermal analysis illustrated moderately effect of sodium polymetaphosphate to show flame-retardancy due to the confinement of phosphate's activity in the polymeric inorganic chain, however this effect increased by using urea.     

INHIBITING EFFECT OF CRYSTAL VIOLET DYE ON ALUMINUM CORROSION IN ACIDIC AND ALKALINE MEDIA

Crystal violet dye (CV) was studied as a corrosion inhibitor for aluminum in hydrochloric acid (1 mol dm^?3) and potassium hydroxide (0.5 mol dm^?3) solutions in the temperature range 30°–60°C using the gravimetric technique. The effect of iodide ions on the inhibiting efficacy of CV was also assessed. CV was found to inhibit Al corrosion in both aggressive media, exhibiting greater inhibition efficiency in 1 M HCl (83.6%) than in 0.5 M KOH (23.0%). Inhibition efficiency in 0.5 M KOH was, however, synergistically increased in the presence of iodide ions to attain values up to 85.3%. Inhibition efficiency in the acidic and alkaline solutions increased with CV concentration but decreased with rise in temperature, suggesting physical adsorption of CV on the Al surface. The calculated values of activation energy (E_a), free energy of adsorption (ΔG_ads), and heat of adsorption (Q_ads) confirm the physisorption mechanism. The inhibitor adsorption characteristics were approximated by the Freundlich adsorption isotherm.     

The synergistic inhibitive effect and some quantum chemical parameters of 2,3-diaminonaphthalene and iodide ions on the hydrochloric acid corrosion of aluminium

The effect of iodide ions on the inhibitive performance of 2,3-diaminonaphthalene (2,3-DAN) in 1 M HCl for aluminium corrosion has been studied using hydrogen evolution (gasometry) measurements at 30 and 40 °C. Results obtained showed that the presence of 2,3-DAN molecules in the corrosive medium (1 M HCl solution) inhibits the corrosion process of aluminium and as the concentration of 2,3-DAN increases the inhibition efficiency also increased at the studied temperatures. A synergistic effect was observed between KI and 2,3-DAN. The experimental results suggest that the presence of iodide ions in the solutions stabilized the adsorption of 2,3-DAN molecules on the metal surfaces and, therefore improve the inhibition efficiency of 2,3-DAN. Phenomenon of physical adsorption is proposed for the inhibition and the process followed the Freundlich adsorption isotherm. The activation energy (E_a), heat of adsorption (Q_ads) and free energy of adsorption for the corrosion process (ΔG_ads) have been evaluated at the different temperatures and the values support the results obtained. Some quantum chemical parameters and the Mulliken charge densities for 2,3-diaminonaphthalene were calculated by the AM1 Semi-empirical method to provide further insight into the mechanism of inhibition of the corrosion process.