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Abstract
Antrodia vaillantii (DC.: Fr.) Ryv., A. serialis (Fr.) Donk, A. sinuosa (Fr.) P. Karsten, A. xantha (Fr.: Fr.) Ryv. and Oligoporus placenta (Fr.) Gilb.& Ryv. form a group of internal brown-rot fungi (‘Porenschwämme’), which are associated with decay of coniferous woodwork in buildings and timber in ground contact. The fungi have similar occurrence, biology, fruit bodies and mycelia. Their nomenclature has a confusing history and is still not uniform. For a better understanding of the domestic pore fungi and for a reliable species differentiation and identification of isolates, the internal transcribed spacer (ITS) of the ribosomal DNA (rDNA) was amplified by polymerase chain reaction and sequenced. Isolates from decayed wood and from culture collections were used. The ITS sequences characteristic of A. vaillantii , A. serialis , A. sinuosa , A. xantha and O. placenta were obtained and deposited in the international databases. The ITS size ranges from 636 to 668 bp. Intraspecific variation was low. A dendrogram was performed for the phylogenetic relationship. Some isolates obtained mislabelled were named correctly according to the ITS sequence. The sequences contribute to our collection of ITS data from internal wood decay fungi made to characterize fungi in culture.
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Abstract
Various aqueous wood preservative solutions containing Cu(II) in the form of copper(II) sulphate or copper(II) octanoate, ethanolamine and in one case octanoic acid were investigated by spectrophotometry, polarography and Electron Paramagnetic Resonance (EPR) spectroscopy. Results have shown the same coordination environment around Cu(II) in all solutions with ethanolamine. Computer simulation of the EPR spectra also revealed that the coordination in the first coordination sphere of copper is the same at low concentration of ethanolamine. At 20% ethanolamine concentration, a mixture of two complexes (one with two nitrogens and the other with three) could be detected. The active compound in the investigated ethanolamine containing solutions is the same when previously synthesised copper(II) octanoate was used, or when copper(II) sulphate and octanoic acid were utilized instead. Fungicidal and leaching experiments with the treated wood resulted in the same conclusion: it is not necessary to use pre-synthesised copper(II) octanoate for the preparation of waterborne copper/ethanolamine wood preservatives. Preservative preparation time and costs can be reduced by simply dissolving copper(II) sulphate and octanoic acid in aqueous ethanolamine solutions.
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Abstract
Nanoparticles containing a fungicide, tebuconazole or chlorothalonil, were prepared as aqueous dispersions to treat sapwood of southern yellow pine (SYP) and birch using conventional pressure treatment methods. The maximum amount of active ingredient (a.i.) delivered into wood was ca. 2 kg a.i./m 3 wood with tebuconazole-containing and 1.6 kg a.i/m 3 wood with chlorothalonil-containing nanoparticles. Nanoparticles were prepared using polyvinylpyridine (PVPy) and polyvinylpyridine-co-styrene with 10% styrene (PVPy-10%-Sty) and with 30% styrene (PVPy-30%-Sty) as matrices. Soil jar tests were performed where nanoparticle-treated SYP was exposed to Gloeophyllum trabeum for 16 weeks and nanoparticle-treated birch was exposed to T. versicolor for 12 weeks. Following exposure to G. trabeum , SYP lost ca. 5% of its mass when treated with tebuconazole-containing nanoparticles (PVPy, PVPy-10%-Sty, PVPy-30%-Sty) with a tebuconazole content of ca. 0.5 kg a.i./m 3 SYP. Similar results were obtained with chlorothalonil-treated SYP (0.5 kg a.i./m 3 ) with PVPy-10%-Sty and PVPy-30%-Sty. Birch exposed to T. versicolor lost ca. 5% mass when tebuconazole (in PVPy and PVPy-30%-Sty) was ca. 0.5 kg a.i./m 3 , while similar results were found with chlorothalonil (PVPy, PVPy-10%-Sty, PVPy-30%-Sty) only at a biocide content of ca. 1.6 kg/m 3 wood.
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Abstract
Essential oils from heartwood and sapwood of the root and stem of J. foetidissima were analyzed by GC/MS. Cedrol, widdrol, 8,14-cedranoxide, 14-hydroxy-β-caryophyllene, widdrene and α-cedrene were found as main components in the oils. The oil from the root heartwood which was collected as fractions during steam distillation was used for the isolation of constituents. Eight compounds were isolated using chromatographic techniques (such as CC, FC, MPLC, prep HPLC and prep TLC) and characterized by spectral methods as cedrol, widdrol, 8,14-cedrandiol, 8,14-cedranoxide, 14-hydroxy-β-caryophyllene, thujopsenal, α-cedrenal and cadalene.
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Density functional theory methods are utilized to investigate structural features and stabilities of the most common lignin dimerization products. It is found that intra-molecular hydrogen bonding acts as a stabilizing force in the lowest-energy conformer(s) of several different dimeric lignin structures. Furthermore, the calculations show that the hypothesis of thermodynamic control of monolignol dimerization accounts for some of the results obtained in experimental studies aimed at determining the ratios of intermonomeric linkages. A quantitative correlation between experimentally observed ratios and calculated relative energies cannot, however, be pointed out.
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June 1, 2005
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Thioacidolysis, periodate oxidation and size exclusion chromatography (SEC) were used for the analysis of spruce lignin samples. The standard thioacidolysis method was modified by including a pre-swelling of the lignocellulosic sample before the reaction, and this gave a higher yield of monomer products. Middle lamella and compression wood lignin was found to contain a larger amount of oligomers after thioacidolysis than normal wood lignin. Analysis by thioacidolysis of a thermomechanical pulp (TMP) revealed that approximately 10% of the β-O-4 structures in the lignin were cleaved due to the mechanical grinding effect. From kraft pulp, the mixture of thioacidolysis products contains a major fraction having a considerably larger molecular mass than the products from spruce wood and TMP. The structure of this material is still unknown.
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In this study several pulp components were characterized by ESR spectroscopy. Free radicals present in the pulp lignin gave a well-defined signal, and the residual lignin content during a bleaching sequence could be followed using this technique. Organic radicals on the pulp carbohydrates were also detected and could be related to the formation of chromophore structures in pulp. Further, ESR spectroscopy made it possible to characterize several transition metal ions in pulp. Special attention was paid to metal retention and the impact of a sodium borohydride treatment, and the formation and evolution of complexes between metal ions and pulp components was scrutinized.
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Atmospheric acetic acid pulp from Japanese white birch was bleached with 1–5% ozone with and without intermediate mild alkaline extraction. Concentrated acetic acid was a more effective bleaching media than water. Mild alkaline extraction of ozone-prebleached pulp was found to be very effective in delignification of the pulp and did not have any undesirable effects on pulp properties. A sufficiently delignified acetic acid pulp was obtained with multi-stage ozone bleaching in Z 1 Z 2 Z 3 or Z 1 EZ 2 EZ 3 bleaching sequence with a total ozone consumption of 2.17% on oven-dry pulp. The pulp from a Z 1 EZ 2 EZ 3 sequence still contained 3.51% acetyl groups, which was 75% of the original amount of acetyl groups in unbleached acetic acid pulp.
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A range of mechanical and physical properties were determined for 96 specimens of chestnut wood and for wood types ranging from compression to tension wood; tests included (1) growth stress, (2) longitudinal Young's modulus in green and air-dried states (3) shrinkage in longitudinal and tangential directions. Anatomical observations permitted determination of the proportion of fibres with a gelatinous layer. The influence of these atypical fibres on macroscopic wood properties is examined and discussed. A basic model is proposed to determine their properties in theoretically isolated conditions.
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The kinetics of phloem and xylem formation of two-year-old plants of Swietenia macrophylla King (true mahogany) was studied in a model system along the shoot circumference (experiment 1) and along the shoot axis (experiment 2). The radius increment of the shoot was registered by high resolution laser measurements (accuracy: ±2 μm) in a spatial resolution of 7.8 to 41.3 μm along the stem circumference and 1.5 mm along the stem axis. The temporal resolution of the measurements was 2 s in experiment 1 and 20 s in experiment 2. The radius increment of the shoot detected by the laser measurements was predominately due to the radial enlargement of the phloem and xylem derivatives. On the phloem side the reinitiation of radial cell enlargement after a cambial dormancy occurred first in sieve tubes with contact to ray parenchyma cells, while on the xylem side the radial cell enlargement of vessels and paratracheal parenchyma was induced almost simultaneously along the shoot circumference. In the phloem and xylem derivatives, which were formed first after the cambial reactivation, radial cell enlargement was induced almost simultaneously along the shoot axis. In more advanced phases of phloem and xylem formation, radial cell enlargement of phloem and xylem derivatives was induced shoot downwards with a rate of approximately 13 mm per min. The mean rate of radial cell enlargement of the phloem and xylem derivatives was 2.26 and 4.37 μm per min, respectively. These findings suggest that the kinetics of cambial growth of tropical tree species differ significantly from kinetics observed in trees from temperate regions. The laser measurements might provide a useful experimental approach for studies of cambial activity in situ .
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This study was conducted to explore basic physical and mechanical properties of parallel strand lumber (PSL) made exclusively from southern pine and yellow-poplar, respectively, and to examine their relationships using statistical analysis. Small specimens were prepared from commercial southern pine PSL and yellow-poplar PSL billets and tested for specific gravity, moisture content, dimensional stability, bending properties, shear strength and compressive strength. Results indicate average specific gravity of southern pine PSL is higher than that of yellow-poplar PSL, while their average moisture content and dimensional stability are very similar. Southern pine PSL has higher average modulus of elasticity but lower average modulus of rupture than yellow-poplar PSL. While average longitudinal shear strength does not exhibit differences between southern pine PSL and yellow-poplar PSL, average compressive strength of southern pine PSL is higher than that of yellow-poplar PSL. There are positive correlations among modulus of elasticity, modulus of rupture and specific gravity. PSL improves some properties of solid wood from which PSL is made.
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Contributions of the cell structure of wood to water sorption were examined using the chemical potential change induced by restrained swelling. Thermodynamic analysis revealed that this potential was proportional to the product of moisture content and the bulk modulus of the restraining region in the wood. The modulus of the restricting region, which was calculated from isotherm curves of wood powder and block samples by using the thermodynamically derived relationship, was near that obtained from the swelling strain and stress in the cross section for whole wood. These results demonstrated that S1 and S3 layers in the cell wall, where thin crystal threads called microfibrils are wound helically in the circumference, act to resist swelling so that the isotherm curve of the block sample was lower than that of wood powder.
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Moisture dynamics in wood during weather exposure as affected by species, origin, production method and painting system were studied for nine years on 170 samples. The moisture content (MC, by dry base) was measured on 67 occasions. Principal component analysis was used for data reduction and pattern recognition. The investigation included two species; Scots pine ( Pinus sylvestris L.) and Norway spruce ( Picea abies L. (Karst)), and showed that the painting method affected the moisture dynamics most. In addition, species and type of wood were important factors, and for pine sapwood also the production method used had an influence on the moisture dynamics. Heartwood of pine had a stable development with low MC throughout the experimental time, regardless of surface treatment or handling method. The pine sapwood samples, on the other hand, had higher average MC and much faster dynamics. For painted and endsealed pine sapwood samples, the drying method was not significant for the MC dynamics, but water storage led to a higher and faster moisture uptake than for samples that were not water-stored. For untreated pine sapwood samples, air-drying led to the highest and fastest moisture uptake, but on the whole this group had unacceptably high moisture uptake. The spruce samples showed very different behaviour depending on whether they were surface treated or not. Painted and endsealed spruce led to two distinct groups, one with moisture dynamics similar to pine heartwood and one with very high moisture uptake and large spread more similar to pine sapwood. Most untreated spruce samples had moisture dynamics comparable to those of pine heartwood.
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