Bioactive compounds and antiradical activity of propolis from scaptotrigona bipunctata e scaptotrigona depilis / Compostos bioativos e atividade antiradical da própolis de scaptotrigona bipunctata e scaptotrigona depilis

Propolis is a viscous substance produced and collected from plant shoots or exudates by worker bees. This study aimed to identify phenolic compounds, carotenoids, volatile compounds, and antiradical activity of propolis obtained from two stingless bees (SB), Scaptotrigona bipunctata (Tubuna) and Scaptotrigona depilis (Canudo), all native from Rio Grande do Sul. The two propolis showed a similar qualitative composition, but with quantitative differences. Catechin was the major phenolic compound found in propolis from S. bipuncata and S. depilis. The propolis from S. depilis showed a higher concentration of carotenoids, mainly lutein. The α-pinene was the volatile compound found in greater concentration in the two propolis.

INVESTIGATION OF THE TEMPERATURE FACTORS INFLUENCE ON OPERATING SAFETY THE SUBMERSIBLE ELECTROMECHANICAL CONVERTER

The article presents a mathematical model of the thermal field for determining the values of temperatures during the submersible electromechanical converter operation. The influence of obtained temperature values on the safety and reliability of the submersible electromechanical converter is analyzed. In a submersible electromechanical converter the windings temperature has great importance. On the one hand, the windings temperature must be such as to transfer a sufficient amount of heat to the viscous loading environment for its processing (movement, transportation, etc.) to begin. On the other hand, the windings temperature must not exceed the limit values for the corresponding insulation class, since this can cause an emergency (fire, short circuit, etc.) The obtained results shows, that temperature on the surface of rotor's cylinders reaches 135 ° C, which provides rapid heating of a viscous substance, and therefore high performance of the pumping process. In this work, the bitumen BND 200/300 was used as the loading and cooling environment. The flash point of this brand of bitumen is 220 ° C and characterizes the degree of flammability of bitumen when it heated. Bitumen does not reach the maximum allowable temperature as a result of heating by means of submersible electromechanical converter that creates a safe temperature corridor in a technological chain at its processing. The temperature of the outer surface of the submersible electromechanical converter, with which the service technical staff may have a contact, does not exceed 20 ° C (Fig. 3), which is completely safe and does not endanger the workers health or life. Also, the obtained temperatures values are within the permissible limits of the heat resistance class of a winding electrical insulating material (H - 180 ° C), which also contributes to the safe submersible electromechanical converter operation.

Effect of Liquid Combustible Components on Coal-Water Fuel Viscosity

The paper presents the experimental studies of coal-water fuel viscosity and suspensions with addition of small amount of various liquid combustible components (isopropyl alcohol, liquid wastes of rubber products processing, and used engine oil) performed. The results show that a liquid combustible component introduced into the suspension causes an increase in the viscosity of the fuel, since the viscosity of the considered liquid combustible components is higher than the viscosity of water. It has been established that the viscosity of slurry fuels based on 3B, D, and T grade coals increases with the increase in the combustible components concentration in the liquid, as less viscous water is replaced by a more viscous substance. Slurry fuel based on 3B grade coal has been determined to have the highest viscosity among the three studied grades, while the slurry fuel based on T grade coal has the smallest viscosity. It has been established that coal-water fuels with addition of a small amount of various liquid combustible components can be used for combustion in boiler units furnaces, since their viscosity and fluidity remain within acceptable limits.

Physical Properties of an Ionic Liquid Composed of Two Water-Soluble Vitamins and Enhanced Skin Permeation of Both Vitamins

A highly viscous substance was prepared by evaporating an ethanol solution containing two hydrophilic vitamins; vitamin C, and vitamin B6. The viscous substance and physical mixture of the two vitamins were tested using a differential scanning calorimeter and an X-ray diffractometer. The highly viscous substance was found to be a liquid crystal (LC) made of these two hydrophilic vitamins. Determination by proton nuclear magnetic resonance measurement suggested that intramolecular hydrogen bonding in vitamin B6 was eliminated by the LC formation. This LC compound showed high solubility in 1,3-butanediol (almost 87%). Much higher skin permeation of both vitamin C and B6 was also observed from the LC compound than that from the physical mixture. The present LC compound containing vitamin C and vitamin B6 may be useful for pharmaceutical and cosmeceutical applications.

Evaluation of the fermentation properties of different soybean (Glycine max L.) cultivars

The enzymatic activity (EA) and amino-type nitrogen (ATN), viscous substance (VS), organic acid (OA), free amino acid (FAA), and volatile compound (VC) content in fermented soybeans of six cultivars (Glycine max L. ‘Taekwangkong’ [TKK], ‘Daechankong’ [DCK], ‘Misokong’ [MSK], ‘Seonpungkong’ [SPK], ‘Uramkong’ [URK], and ‘Chamolkong’ [COK]) were compared. Fermentation increased the quality indices such as EA, ATN and VS in soybean, and their highest content were observed in DCK. The content of major OAs decreased in the following order: lactic acid > acetic acid > fumaric acid. The essential amino acid (EAA) content was increased by fermentation, and FAA production had a positive effect on the abundance of the fermentation metabolites ã-amino-n-butyric acid and ornithine. The content of the VS pyrazine differed with cultivar. Overall, soybean cultivars showed differences in the composition and fermentation properties, with raw DCK soybeans being particularly suitable for fermentation.

PREPARATION OF SOLID LIPID NANOPARTICLES CONTAINING MANGOSTEEN PERICARP EXTRACT

Objectives: The aim of this study was to develop solid lipid nanoparticles (SLNs) containing mangosteen pericarp extract (MPE) to achieve enhanced photoprotection and to provide an alternative to synthetic sunscreens in the market.Materials and Methods: The MPE was prepared using the maceration method, and evaluated for sun protection factor (SPF) value using an ultraviolet (UV)-Vis spectrophotometer. SLNs were prepared through ultrasonication method. Blank-SLNs were formulated using stearic acid (SA) or palmitic acid (PA) as solid lipids at a concentration of 3%. Tween® 80 or polyvinyl alcohol (PVA) was employed as a surfactant with a concentration ranging from 1 to 2%. The obtained blank-SLNs were investigated for their physical characteristics, (i.e., morphology, particle size, polydispersity index [PDI], and zeta potential values). The blank-SLNs with suitable physical characteristics were selected to encapsulate MPE and evaluated for the physical characteristics.Results: The MPE was a brownish viscous substance with an SPF value that ranged from 3.09±0.005 to 27.20±0.05 at a concentration ranging from 0.02 to 0.1 mg/ml. Based on the physical characteristics, the blank-SLNs employing PA or SA with 1% of PVA were selected. The MPE-SLNs were spherical, with a particle size that ranged from 443.51±6.50 to 533.52±16.15 nm; PDI ranged from 0.35±0.008 to 0.459±0.02, and zeta potential value ranged from 18.32±1.37 to −19.03±0.64. The entrapment efficiencies of MPE-PA-SLNs and MPE-SA-SLNs were 83.24±1.37% and 84.17±0.411%, respectively.Conclusion: The results indicated the promising potential of MPE as a UVB photoprotector. The MPE-SLNs were also successfully formulated, but, further study is needed to confirm the potential of MPE-SLNs to be used as a sunscreen, and their stability during storage.

Venezuela in the Twentieth Century

When was oil discovered? Petroleum and natural gas seeps, produced by fissures in the earth, dot the landscape in various regions of eastern and western Venezuela. The indigenous people labeled these occurrences menes, and they used the viscous substance to weatherproof structures,...