Application Of Oleic Acid Research Articles

Results of fibre and toner flotation depending on oleic acid dosage.

The literature was reviewed with respect to deinking flotation methods with toner samples, specifically emphasizing the speciation of copy machine and laser printing, which produce an increasing quantity of paper that is difficult to recycle. Speciation here refers to the physical-chemical characteristics of the toner, which change because of the polymerization (fusion) and oxidation process, due to exposure to heat, light and oxygen (air) during the printing process. To simulate the deinking flotation, after the ideal disintegration process, samples of toner were prepared in order to provide free toner particles. Synthetic toner has iron content and the same physical-chemical features as free disintegrated printed toner particles.We report the toner (I) and fibre (Y) recovery and the brightness (B) of laboratory filter pads formed of deinked product as deinking efficiencies. The application of oleic acid as the collector in the flotation stage gives a better flotation recovery in alkaline than in acidic conditions. The highest brightness (BF = 93.66%) and flotation recoveries (I = 90, Y = 92.82%) were achieved during testing at an oleic acid concentration of 3.38·10(-6) mol l(-1), which is the lowest dose used. This makes the use of oleic acid economical and environmentally friendly.

Friction and Wear Characteristics of Oil-Based ZnO Nanofluids

Nanofluids have been an active area of research for almost two decades due to their enhanced thermal conductivity compared to base fluids, but the study of nanofluids for tribological purposes has been slow, with problems encountered in dispersing and stabilizing nanoparticles in lubricants. In this research, the tribological properties of nanofluids were studied through experimental investigation by dispersing ZnO nanoparticles into paraffinic mineral oil. Nanoparticles were dispersed using an ultrasonic homogenizer. Oleic acid was used as the surfactant for the improved dispersibility and stability of nanofluids. A universal microtribometer with a ball-on-disk configuration was used to evaluate the friction properties between the moving mechanical components in the presence of nanofluids. The wear track was measured using a surface profiler, and the material deposition onto the sliding interface was analyzed using X-ray photoelectron spectroscopy. The effects of the surfactant, ultrasonication time, particle concentration, applied load, sliding velocity, and surface roughness on the friction and wear performance of nanofluids were investigated. The results showed that oil-based nanofluids with ZnO nanoparticles reduced friction and wear under certain conditions, and the application of oleic acid as a dispersant contributed to reducing friction to some extent and also improved the dispersibility and stability of the nanofluids.

Unsaturated Fatty Acids Induce Calcium Influx into Keratinocytes and Cause Abnormal Differentiation of Epidermis

Abnormal follicular keratinization is involved in comedogenesis in acne vulgaris. We recently demonstrated that calcium influx into epidermal keratinocytes is associated with impaired skin barrier function and epidermal proliferation. Based on these results, we hypothesized that sebum components affect calcium dynamics in the keratinocyte and consequently induce abnormal keratinization. To test this idea, we first observed the effects of topical application of sebum components, triglycerides (triolein), saturated fatty acids (palmitic acid and stearic acid), and unsaturated fatty acids (oleic acid and palmitoleic acid) on hairless mouse skin. Neither triglyceride nor saturated fatty acids affected the skin surface morphology or epidermal proliferation. On the other hand, application of unsaturated fatty acids, oleic acid, and palmitoleic acid induced scaly skin, abnormal keratinization, and epidermal hyperplasia. Application of triglycerides and saturated fatty acids on cultured human keratinocytes did not affect the intracellular calcium concentration ([Ca(2+)](i)), whereas unsaturated fatty acids increased the [Ca(2+)](i) of the keratinocytes. Moreover, application of oleic acid on hairless mouse skin induced an abnormal calcium distribution in the epidermis. These results suggest that unsaturated fatty acids in sebum alter the calcium dynamics in epidermal keratinocytes and induce abnormal follicular keratinization.

Examination of the mechanism of oleic acid-induced percutaneous penetration enhancement: an ultrastructural study.

The epidermal permeability barrier appears to be regulated primarily by the lamellar arrangement of lipid bilayers between coneocytes of the stratum corneum and presents a significant barrier to the transdermal delivery of drugs. The aim of the present study was to investigate the effects of oleic acid on the ultrastructure of stratum corneum lipids in rat skin. Wistar rats were treated topically with 10% oleic acid/propylene glycol for 2 h, the structure of stratum corneum was examined by electron microscopy using osmium tetroxide or ruthenium tetroxide postfixation, and the epidermal barrier function was evaluated in a lanthanum tracer study. Ultrastructural examination revealed that there was a marked alteration in the stratum corneum and the tracer penetrated into the intercellular spaces of the stratum corneum after application of oleic acid. These results suggest that ruthenium tetroxide postfixation is a powerful tool for the study of the stratum corneum lipid structure. Oleic acid might increase the epidermal permeability through a mechanism involving the perturbation of stratum corneum lipid bilayers and lacunae formation to enhance transdermal drug delivery.

Characteristics of the pulmonary transport functions for heat and dye in pulmonary edema and orthostasis.

The aim of this study was to investigate whether changes in the distribution of pulmonary blood flow and disturbances of the pulmonary microcirculation can be detected by use of inflow-outflow indicator-dilution measurements. In 18 anesthetized (N2O-piritramide) mongrel dogs 221 thermal-indocyanine green dye indicator dilution kinetics were recorded in the pulmonary artery and aorta after central venous indicator injection. The lagged normal density function was used as a model for the pulmonary transport functions for heat and dye. The parameters of the lagged normal density function were computed by a non-linear least squares procedure by iterative convolution. After baseline measurements, in nine dogs, pulmonary edema was induced by central venous application of oleic acid. In nine other dogs, measurements were performed before and after postural changes. Our data show that both the microvascular injury caused by oleic acid edema and the perfusion heterogeneity caused by orthostasis can be detected by the indicator dilution technique since the both relative dispersion and skewness of the transport functions for heat and dye were significantly increased after these interventions.