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RESIDUAL NONAQUEOUS PHASE LIQUID DISSOLUTION IN MICROMODELS
M. Yavuz Corapcioglu,Chowdhury, Sabina,Roosevelt, Sharon E. 嶺南大學校 環境問題硏究所 1997 環境硏究 Vol.16 No.2
AbstractNonaqueous phase liquids (NAPLs) such as gasoline and halogenated solvents enter the subsurface after a spill, or from leaking underground storage tanks. NAPLs trapped by capillary forces in subsurface environments pose a long-term threat to drinking water supplies. The main challenge in site remediation lies in dealing with the dissolving NAPL source (Corapcioglu and Baehr, 1987). An understanding and quantification of the NAPL dissolution process at pore-scale is of utmost importance in estimating the source of existing dissolved compounds and in evaluating the effciency of in-situ remediation of NAPL contaminated aquifers.The use of small-scale artificial models of porous media known as micromodels is a novel approach to simulate transport phenomena in porous media Micromodels are artificial two-dimensional network models of interconnecting pores and throats that can simulate natural porous media up to a certain degree. Micromodels give insight to the pore-scale interplay of various aspects of transport phenomena. Micromodels are commonly fabricated by etching the desired pore network pattern on two plates of mirror glass which are then fused together.In this study, we investigated the dissolution kinetics of residual NAPLs in a porous medium by conducting micromodel experiments. Dissolution of residual NAPLs was quantified by direct observation of the dissolution mechanism in a micromodel. We processed video images with an image analyzer to measure the temporal change of irregularly shaped NAPL blobs in a heterogeneous porous medium in order to calculate the mass transfer coefficient as well as the mass transfer rate coefficient. Relationships between the mass transfer rate coefficient, mass transfer coefficient, residual NAPL saturation and flow velocity were examined.The dissolution process was also investigated by separating the mass transfer into two zones of mobile and immobile water. This type of bicontinuum approximation of the fluid velocity field assumes that convective-dispersive transport occurs in the mobile region, while the water remains stagnant in the immobile region which is connected to the mobile region. Although this concept is not new, the estimation of the interfacial area and the fraction of area in the mobile region have not been contemplated due to the inherent difficulty in measuring these parameters. We introduced a methodology to evaluate separate coefficients for NAPL dissolution in the mobile and immobile water region by measuring the fraction of total residual NAPL in contact with mobile water, immobile water, and solid surfaces.
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Alexandra Allemand,Bianca Franco Leonardi,Aline Rigon Zimmer,Susana Moreno,Pedro Roosevelt Torres Romao,Grace Gosmann 한국식품영양과학회 2016 Journal of medicinal food Vol.19 No.8
Capsicum baccatum is the most consumed red pepper species in Brazil. Our previous studies demonstrated the anti-inflammatory properties of its crude extract, whose activity is yet to be fully characterized. Herein, we examined the antiinflammatory in vivo effects of enriched extracts obtained through bioguided fractionation as dichloromethane (DCM), butanol (BUT), and residual aqueous (RAq) extracts and its influence on inflammatory mediators produced by macrophages in vitro. We demonstrated that all C. baccatum extracts presented anti-inflammatory activity in vivo. In addition, we showed that BUT and RAq were more effective in inhibiting the neutrophil migration induced by carrageenan (Cg) to peritoneal cavity and both extracts inhibited paw edema induced by Cg, prostaglandin E2, and histamine in mice. Furthermore, the pretreatment with C. baccatum extracts significantly reduced the levels of myeloperoxidase (MPO) in the paw tissues of mice compared with the carrageenan group. Once again, RAq and BUT caused the greatest reduction in MPO levels. Moreover, it was demonstrated for the first time that C. baccatum inhibited the nitric oxide and tumor necrosis factor-alpha production by lipopolysaccharide/interferon gamma (IFN-c)-stimulated macrophages. These anti-inflammatory effects seem to be at least, in part, independent of capsaicin. Hence, red pepper has bioactive compounds and might be used to develop food-derived extracts to treat related inflammatory diseases.
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Cleide Adriane Signor Tirloni,Aniely Oliveira Silva,Rhanany Alan Calloi Palozi,Paulo Cesar de Paula Vasconcelos,Roosevelt Isaias Carvalho Souza,Ariany Carvalho dos Santos,Valter Paes de Almeida,Jane M 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.12
Talisia esculenta (A. St.-Hil.) Radlk. is a large tree belonging to family Sapindaceae and popularly known as “pitombeira” or “pitomba.” Although species have relevant economic and medicinal uses in Brazil, no study has investigated its effectiveness as a diuretic, hypotensive, and antihypertensive agent. The aim of this study was to present a detailed anatomical and histochemical study for T. esculenta and provide important safety and efficacy parameters. After morpho-anatomical and microchemical study, a purified aqueous extract (ethanol soluble fraction obtained from T. esculenta [ESTE]) was obtained, and detailed phytochemical investigation was performed. Subsequently, acute oral toxicity test was performed in male and female rats. Moreover, diuretic, hypotensive, and antihypertensive effects on normotensive and spontaneously hypertensive rats (SHR) were investigated. Finally, the effects of prolonged treatment with ESTE on serum levels of nitrite, thiobarbituric acid reactive species, and nitrotyrosine were also measured in SHR. Oral treatment with ESTE did not induce acute toxic effects and did not affect urine production, blood pressure, or heart rate of normotensive and SHR. Prolonged treatment with ESTE was able to increase serum nitrite levels and significantly reduce oxidative and nitrosative stress markers in SHR. Data obtained showed that ESTE has a significant antioxidant activity without showing any clinical signs of acute toxicity. The use of this species as a diuretic, hypotensive, or antihypertensive agent should be carried out with caution, since administration in rodents did not produce renal and/or hemodynamic responses that justify this indication.
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