This paper describes the principle of measuring the pressure-viscosity relation in mineral oil by the capillary method, and the ftrst experimental equipment for measuring the pressure-viscosity relation in our country...This paper describes the principle of measuring the pressure-viscosity relation in mineral oil by the capillary method, and the ftrst experimental equipment for measuring the pressure-viscosity relation in our country—type NY-1 capillary pressuer-viscosity equipment, which is designed by the authors. The experimental investigation into four kinds of mineral oil is completed on the equipment. The range of pressure is 0 to 0.1 GPa. The experimental results show that the pressure-viscosity relations in the four kinds of mineral oil agree with the Barus equation.展开更多
We address the flow of incompressible fluid with a pressure-dependent viscosity through a pipe with helical shape. The viscosity-pressure relation is defined by the Barus law. The thickness of the pipe and the helix s...We address the flow of incompressible fluid with a pressure-dependent viscosity through a pipe with helical shape. The viscosity-pressure relation is defined by the Barus law. The thickness of the pipe and the helix step are assumed to be of the same order and considered as the small parameter. After transforming the starting problem, we compute the asymptotic solution using curvilinear coordinates and standard perturbation technique. The solution is provided in the explicit form clearly showing the influence of viscosity-pressure dependence and pipe＇s geometry on the effective flow.展开更多
The rational design of emulsions requires study of the main factors that influence their formation, physicochemical properties and, consequently, stability and performance. The use of vegetable oils in the pharmaceuti...The rational design of emulsions requires study of the main factors that influence their formation, physicochemical properties and, consequently, stability and performance. The use of vegetable oils in the pharmaceutical and cosmetic industries has recently become attractive. Dipteryx alata Vogel(D. alata) is an oleaginous species native to Brazil. The seeds of this species contain highly unsaturated oil with significant amounts of tocopherols and phytosterols, representing an important source of agents capable of combatting oxidative processes. In this work, a lamellar gel phase emulsion using oil extracted from the seeds of D. alata(baru) was developed. The steps involved in the development of this research were as follows: 1) development of formulations and 2) in vitro assays by simulating the evaporation of the final product after application to the skin and Electron paramagnetic resonance spectroscopy(EPR) of fatty acid spin labels was used to investigate the profile of interaction of the dispersed systems with stratum corneum(SC) lipids. The results indicate that the developed system shows no signs of instability during the storage period. Moreover, EPR studies indicated that D. alata oil and especially the developed formulation were able to increase SC lipid fluidity and extract a fatty-acid spin label from the lipid domain structures of SC, demonstrating its potential to act as a drug or skin care vehicle.展开更多
Phenolic compounds from Dipteryx alata Vogel were assayed against the in vitro neurotoxic effect induced by Bothrops jararacussu (Bjssu) venom. Mutagenicity was assessed by the Ames test using Salmonella typhimurium s...Phenolic compounds from Dipteryx alata Vogel were assayed against the in vitro neurotoxic effect induced by Bothrops jararacussu (Bjssu) venom. Mutagenicity was assessed by the Ames test using Salmonella typhimurium strains TA98, TA97a, TA100, and TA102, in experiments with and without metabolic activation. Anti-bothropic activity was obtained by using mouse phrenic nerve-diaphragm (PND) preparation and myographic technique. Control experiments with physiological Tyrode solution were used for keeping the PND preparations alive (n = 4). Concentrations of phe-nolic compounds were as follow: protocatechuic and vanillic acids (200 μg/mL, n = 4), vanillin (50 μg/mL, n = 4). These compounds were used alone or pre-incubated with the venom (40 μg/mL), 30 min prior the addition to the organ bath (n = 4). Phenolic compounds significantly inhibited the neuromuscular blockade of Bjssu in the following order of potency: vanillic acid > protocatechuic = vanillin. Vanillic acid added 10 min after the Bjssu venom was also able to avoid the venomblockade evolution. The mutagenicity assay indicated that all phytochemicals were unable to in-crease the number of revertants, demonstrating the absence of mutagenic activity. This study demonstrated both the safety and therapeutical potential of the three phenolic compounds as novel complementary anti-bothropic agents.展开更多
文摘This paper describes the principle of measuring the pressure-viscosity relation in mineral oil by the capillary method, and the ftrst experimental equipment for measuring the pressure-viscosity relation in our country—type NY-1 capillary pressuer-viscosity equipment, which is designed by the authors. The experimental investigation into four kinds of mineral oil is completed on the equipment. The range of pressure is 0 to 0.1 GPa. The experimental results show that the pressure-viscosity relations in the four kinds of mineral oil agree with the Barus equation.
基金supported by the Croatian Science Foundation(scientific project 3955:Mathematical modeling and numerical simulations of processes in thin or porous domains)
文摘We address the flow of incompressible fluid with a pressure-dependent viscosity through a pipe with helical shape. The viscosity-pressure relation is defined by the Barus law. The thickness of the pipe and the helix step are assumed to be of the same order and considered as the small parameter. After transforming the starting problem, we compute the asymptotic solution using curvilinear coordinates and standard perturbation technique. The solution is provided in the explicit form clearly showing the influence of viscosity-pressure dependence and pipe＇s geometry on the effective flow.
基金supported by CAPES (Coordenacao de Aperfeicoamento de Pessoal de Ensino Superior) through a student fellowship to C.S.S. Moraes
文摘The rational design of emulsions requires study of the main factors that influence their formation, physicochemical properties and, consequently, stability and performance. The use of vegetable oils in the pharmaceutical and cosmetic industries has recently become attractive. Dipteryx alata Vogel(D. alata) is an oleaginous species native to Brazil. The seeds of this species contain highly unsaturated oil with significant amounts of tocopherols and phytosterols, representing an important source of agents capable of combatting oxidative processes. In this work, a lamellar gel phase emulsion using oil extracted from the seeds of D. alata(baru) was developed. The steps involved in the development of this research were as follows: 1) development of formulations and 2) in vitro assays by simulating the evaporation of the final product after application to the skin and Electron paramagnetic resonance spectroscopy(EPR) of fatty acid spin labels was used to investigate the profile of interaction of the dispersed systems with stratum corneum(SC) lipids. The results indicate that the developed system shows no signs of instability during the storage period. Moreover, EPR studies indicated that D. alata oil and especially the developed formulation were able to increase SC lipid fluidity and extract a fatty-acid spin label from the lipid domain structures of SC, demonstrating its potential to act as a drug or skin care vehicle.
文摘Phenolic compounds from Dipteryx alata Vogel were assayed against the in vitro neurotoxic effect induced by Bothrops jararacussu (Bjssu) venom. Mutagenicity was assessed by the Ames test using Salmonella typhimurium strains TA98, TA97a, TA100, and TA102, in experiments with and without metabolic activation. Anti-bothropic activity was obtained by using mouse phrenic nerve-diaphragm (PND) preparation and myographic technique. Control experiments with physiological Tyrode solution were used for keeping the PND preparations alive (n = 4). Concentrations of phe-nolic compounds were as follow: protocatechuic and vanillic acids (200 μg/mL, n = 4), vanillin (50 μg/mL, n = 4). These compounds were used alone or pre-incubated with the venom (40 μg/mL), 30 min prior the addition to the organ bath (n = 4). Phenolic compounds significantly inhibited the neuromuscular blockade of Bjssu in the following order of potency: vanillic acid > protocatechuic = vanillin. Vanillic acid added 10 min after the Bjssu venom was also able to avoid the venomblockade evolution. The mutagenicity assay indicated that all phytochemicals were unable to in-crease the number of revertants, demonstrating the absence of mutagenic activity. This study demonstrated both the safety and therapeutical potential of the three phenolic compounds as novel complementary anti-bothropic agents.
