Displaying all 3 publications

Abstract:
Sort:
  1. Silica colloids as non-carriers facilitate Pb2+ transport in saturated porous media under a weak adsorption condition: effects of Pb2+ concentrations
    Dai C, Zhou H, You X, Duan Y, Tu Y, Liu S, et al.
    Environ Sci Pollut Res Int, 2020 May;27(13):15188-15197.
    PMID: 32072419 DOI: 10.1007/s11356-020-08064-0
    Transport of environmental pollutants in groundwater systems can be greatly influenced by colloids. In this study, the cotransport of Pb2+ and silica (SiO2) colloids at different Pb2+ concentrations was systematically investigated by batch adsorption and saturated sand column experiments. Results showed that SiO2 colloids had low adsorption capacity for Pb2+ (less than 1% of the input) compared with sands. In saturated porous media, SiO2 colloids showed a high mobility; however, with the increase of Pb2+ concentration in the sand column, the mobility of SiO2 colloids gradually decreased. Notably, SiO2 colloids could facilitate Pb2+ transport, although they did not serve as effective carriers of Pb2+. Under the condition of low Pb2+ concentration, SiO2 colloids promoted the Pb2+ transport mainly through the way of "transport channel," while changing the porosity of the medium and masking medium adsorption sites were the main mechanisms of SiO2 colloid-facilitated Pb2+ transport under the condition of high Pb2+ concentration. The discovery of this non-adsorption effect of colloids would improve our understanding of colloid-facilitated Pb2+ transport in saturated porous media, which provided new insights into the role of colloids, especially colloids with weak Pb2+ adsorption capacity, in Pb2+ occurrence and transport in soil-groundwater systems.
  2. In Vitro Inhibitory Effects of Agarwood Tea (Aquilaria malaccensis Lamk) Aqueous Extract on Human Cytochrome P450 (CYP) Enzyme Activities
    Yan P, Tze UY, Jagadish PAR, Hon LK, Chowdhury LNS, Tao S, et al.
    Drug Metab Bioanal Lett, 2022;15(3):178-191.
    PMID: 36508274 DOI: 10.2174/1872312815666220707114744
    BACKGROUND: Agarwood tea derived from Aquilaria malaccensis Lamk is becoming an increasingly popular herbal drink that is said to have multiple health benefits. Co-administration of this tea and clinical used drugs is possible, but it increases the risk of drug-herb interactions.

    OBJECTIVE: This in vitro study investigated the inhibitory effects of agarwood tea aqueous extract on the eight major human drug-metabolising cytochrome P450 (CYP) enzyme activities.

    METHODS: High-throughput fluorescence-based Vivid® CYP450 screening kits were employed to obtain the enzyme activities before and after incubation with agarwood tea aqueous extract.

    RESULTS: Agarwood aqueous extract potently inhibited CYP2C9, CYP2D6, and CYP3A4 activities with Ki values of 5.1, 34.5, and 20.3μg/ml, respectively. The most likely inhibition mode responsible for these inhibitions was non-competitive inhibition. On the other hand, at 1000μg/ml, agarwood tea aqueous extract negligibly inhibited CYP1A2, CYP2B6, CYP2C19, CYP2E1, and CYP3A5 activities.

    CONCLUSION: These findings can be used to design additional in vitro investigations using clinical relevant drug substrates for CYP2C9, CYP2D6, and CYP3A4. Subsequently, future studies can be conducted to determine potential interactions between agarwood tea aqueous extract and CYP using in vivo models.

  3. Transport of TiO2 and CeO2 nanoparticles in saturated porous media in the presence of surfactants with environmentally relevant concentrations
    Dai C, Shen H, Duan Y, You X, Lai X, Liu S, et al.
    Environ Sci Pollut Res Int, 2021 Sep 09.
    PMID: 34505247 DOI: 10.1007/s11356-021-16266-3
    Nanomaterials are threatening the environment and human health, but there has been little discussion about the stability and mobility of nanoparticles (NPs) in saturated porous media at environmentally relevant concentrations of surfactants, which is a knowledge gap in exploring the fate of engineered NPs in groundwater. Therefore, the influences of the anionic surfactant (sodium dodecylbenzene sulfonate, SDBS), the cationic surfactant (cetyltrimethylammonium bromide, CTAB), and the nonionic surfactant (Tween-80) with environmentally relevant concentrations of 0, 5, 10, and 20 mg/L on nano-TiO2 (nTiO2, negatively charged) and nano-CeO2 (nCeO2, positively charged) transport through saturated porous media were examined by column experiments. On the whole, with increasing SDBS concentration from 0 to 20 mg/L, the concentration peak of nTiO2 and nCeO2 in effluents increased by approximately 0.2 and 0.3 (dimensionless concentration, C/C0), respectively, because of enhanced stability and reduced aggregate size resulting from enhanced electrostatic and steric repulsions. By contrast, the transportability of NPs significantly decreased with increasing CTAB concentration due to the attachment of positive charges, which was opposite to the charge on the medium surface and facilitated the NP deposition. On the other hand, the addition of Tween-80 had no significant influence on the stability and mobility of nTiO2 and nCeO2. The results were also demonstrated by the colloid filtration theory (CFT) modeling and the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction calculations; it might promote the assessment and remediation of NP pollution in subsurface environments.
Related Terms
    Try searching for something
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links