Organic materials including a peat-mineral mix (PM), a forest floor-mineral mix (L/S), and a combination of the two (L/PM) were used to cap mineral soil materials at surface mine reclamation sites in the Athabasca oil sands region of northeastern Alberta, Canada. The objective of this study was to test whether LFH provided an advantage over peat by stimulating microbial activity and providing more available nitrogen for plant growth. Net nitrification, ammonification, and N mineralization rates were estimated from field incubations using buried bags. In situ gross nitrification and ammonification rates were determined using the 15N isotope pool dilution technique, and microbial biomass C (MBC) and N (MBN) were measured by the chloroform fumigation-extraction method. All reclaimed sites had lower MBC and MBN, and lower net ammonification and net mineralization rates than a natural forest site (NLFH) used as a control, but the reclamation treatment using LFH material by itself had higher gross and net nitrification rates. A positive correlation between in situ moisture content, dissolved organic N, MBC, and MBN was observed, which led us to conduct a moisture manipulation experiment in the laboratory. With the exception of the MBN for the L/S treatment, none of the reclamation treatments ever reached the levels of the natural site during this experiment. However, materials from reclamation treatments that incorporated LFH showed higher respiration rates, MBC, and MBN than the PM treatment, indicating that the addition of LFH as an organic amendment may stimulate microbial activity as compared to the use of peat alone.

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Interactions of silybin and dihydroquercetin (taxifolin), flavanonols from milk thistle [Silybum marianum (L.) Gaertn.] fruits, with Langmuir monolayers of lecithin and bilayers of liposomes are compared. It is established that the investigated flavanonols have different mechanisms of action. Taxifolin produces predominantly membrane-stabilizing action whereas silybin is characterized by immobilization in the hydrophobic part of the phospholipid bilayer with the formation of more hydrophilic micellar structures. The presence of silybin and taxifolin in the liquid extract of milk thistle fruits suggests that a dual mechanism of action may occur in this preparation and also in other combined medicines based on these fruits. The results of this study show good prospects for creating combined preparations based on milk thistle fruit, taxifolin, and other flavonoids (quercetin, rutin, diosmin, etc.) possessing pronounced membrane-stabilizing action.

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