24 research outputs found

    Effect of soil sieving on respiration induced by low-molecular-weight substrates

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    The mesh size of sieves has a significant impact upon soil disturbance, affecting pore structure, fungal hyphae, proportion of fungi to bacteria, and organic matter fractions. The effects are dependent upon soil type and plant coverage. Sieving through a 2 mm mesh increases mineralization of exogenously supplied carbohydrates and phenolics compared to a 5 mm mesh and the effect is significant (p<0.05), especially in organic horizons, due to increased microbial metabolism and alteration of other soil properties. Finer mesh size particularly increases arabinose, mannose, galactose, ferulic and pthalic acid metabolism, whereas maltose mineralization is less affected. Sieving through a 5 mm mesh size is suggested for all type of experiments where enhanced mineralization of low-molecular-weight organic compounds needs to be minimalized

    Effect of soil sieving on respiration induced by low-molecular-weight substrates

    No full text
    The mesh size of sieves has a significant impact upon soil disturbance, affecting pore structure, fungal hyphae, proportion of fungi to bacteria, and organic matter fractions. The effects are dependent upon soil type and plant coverage. Sieving through a 2 mm mesh increases mineralization of exogenously supplied carbohydrates and phenolics compared to a 5 mm mesh and the effect is significant (p<0.05), especially in organic horizons, due to increased microbial metabolism and alteration of other soil properties. Finer mesh size particularly increases arabinose, mannose, galactose, ferulic and pthalic acid metabolism, whereas maltose mineralization is less affected. Sieving through a 5 mm mesh size is suggested for all type of experiments where enhanced mineralization of low-molecular-weight organic compounds needs to be minimalized

    Synthesis of Linear High Molar Mass Glycidol-Based Polymers by Monomer-Activated Anionic Polymerization

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    Linear polyglycidols of high molar masses were prepared by the monomer-activated anionic polymerization of the corresponding protected monomers, ethoxyethyl glycidyl ether and tert-butyl glycidyl ether, using a system composed of tetraoctylammonium bromide as initiator and triisobutylaluminum as monomer activator. The aluminic compound was used in 1.5-5-fold excess compared to the initiator. Linear poly(ethoxyethyl glycidyl ether) and poly(tert-butyl glycidyl ether), with narrow chain dispersity and controlled high molar masses, up to 85000 g/mol, were prepared at 0 degrees C in a few hours. Deprotection of hydroxyl functions by acidic treatment of file polymers was shown to proceed quantitatively and cleanly affording the corresponding linear polyglycerol and validating the use of these protecting groups. The copolymerization of protected glycidols with propylene oxide and butene oxide was also investigated with the goal to broaden the scope of this synthetic approach to various polyethers and copolyethers
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