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To test the effects of calcium on wood formation, Populus tremula x Populus tremuloides clones were supplied with Hoagland solution modified in its calcium contents. Energy-dispersive X-ray analysis (EDXA) revealed an increase in calcium in the phloem, the cambium and the xylem elongation zone with increasing Ca(2+) supply in the nutrient solution. Using… (More)
Relevant parameters for the hardening of acid catalyzed and water based adhesives (e.g. MUF) are certain wood characteristics such as water absorption capacity, pH-value, buffering capacity towards acid and extractive content. This study was performed to characterize these parameters for beech (Fagus sylvatica L.) and ash (Fraxinus excelsior L.) with and… (More)
The lignin distribution in cell walls of spruce and beech wood was determined by high-voltage transmission-electron-microscopy (TEM) in sections stained with potassium permanganate as well as by field-emission-scanning-electron-microscopy (FE-SEM) combined with a back-scattered electron detector on mercurized specimens. The latter is a new technique based… (More)
The weight percentage gain (WPG) and the acetyl group content of wood due to acetylation with acetic anhydride have been analyzed by means of Fourier transform infrared spectroscopy (FTIR) and near-infrared spectroscopy (NIR). Band height ratios (BHR) (1240/1030 (1230/1030) and 1745/1030 (1740/1030)) of the bands at 1745 (1740), 1240 (1230), and 1030 cm-1… (More)
subjected to a given range of atmospheric conditions in service (Handbook of hardwoods 1972). The data presented indicate substantial differences in inherent drying, swelling and sorption characteristics between different botanical species and between sapand heartwood of the same species. In Manilkara zapota for instance, the equilibrating time for… (More)
Crude cyclohexane and ethanol extracts from D. granadillo as well as ethanol extracts from E. cyclocarpum proved inhibitive to fungal growth. Purification of the cyclohexane extract from D. granadillo, using silica-gel column chromatography, revealed even higher anti fungal activity for the second fraction.
New methodology for the preparation of L-isoserine and its incorporation into N- and C-terminal position of peptides is described. Furthermore, the new protective group strategy allows regioselective functional group manipulation in multifunctional amino acids like serine and isoserine.
Anatomical differences were seen between tumorous and normal wood whereas noticeable differences were not detected in the chemical composition.
Evolved gas analysis (EGA) in combination with analytical pyrolysis is presented as a new technique for rapid investigations into wooden materials. In a first analytical step, the thermal behaviour of three wood samples was determined by EGA. Based on these results, analytical pyrolysis–gas chromatography/mass spectrometry was carried out to investigate the… (More)