24 research outputs found
Effect of soil sieving on respiration induced by low-molecular-weight substrates
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
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
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