Your search resulted in 86 documents. Displaying 25 entries per page.
Multiscale modification on water resistance and dimensional stability of Populus cathayana by alkali lignin combined with heat treatment
2018 - IRG/WP 18-40826
The aim of this study was to enhance the water resistance and dimensional stability of fast growing wood by alkali lignin combined with heat treatment. Poplar (Populus cathayana) samples were first impregnated with alkali lignin solution and then subjected to heat treatment at 140, 160, and 180°C respectively for 2h. Properties of leachability, moisture adsorption and water absorption, contact an...
H Zhou, J Li, E Ma
Effect of medium-term degradation of beech wood by erosive (Phanerochaete chrysosporium) and lignin-selective (Ceriporiopsis subvermispora) strains of white rot fungi on its selected physical properties
2004 - IRG/WP 04-40292
At the Faculty of Wood Sciences and Technology a fungal delignification of normal and tension beech wood by erosive and lignin-selective strains white-rot fungi has been studied. The pre-treatment of both kind of wood samples was accompanied by partial delignification and apparent changes of their physical properties influencing the polar liquids penetration....
R Solár, S Kurjatko, M Mamonová, J Hudec
Changes in the degree of decay of lignocellulosic substrate used in a screening test of fungicidal wood preservatives
1977 - IRG/WP 287
This report contains results of investigations aimed at: a) determination of the effect of the kind of substrate and species of test fungus on quantitative changes in used samples prepared from spruce cardboard, and b) comparison of the threshold fungicidal values of come fungicides determined with accelerated method, with values obtained by block method. During performed investigations, the metho...
Comparative studies on the distribution of lignin and CCA elements in birch using electron microscopic X-ray microanalysis
1987 - IRG/WP 1328
The microdistribution of metal preservatives in treated wood has received considerable research over the last two decades. Despite this, little effort seems to have been made to try and correlate the distribution of CCA elements with respect to naturally occurring wood cell wall components in wood. In the present preliminary study an attempt is made to relate the distribution of lignin in-situ wit...
G F Daniel, T Nilsson
A discussion of current theories concerning CCA fixation
1983 - IRG/WP 3238
The understanding of the fixation mechanism of CCA and related preservatives in wood has been greatly improved by a significant series of recent scientific papers. In view of recent concerns in New Zealand regarding the long-term efficacy of CCA in high decay-hazard situations, it was considered appropriate to review this recent work and to contrast it with theories presented by previous workers....
D V Plackett
The use of C CP/MAS NMR in the chemical identification of decayed and undecayed, tropical timber species
1984 - IRG/WP 1224
13C CP/MAS NMR was found to be an extremely powerful tool for elucidating the chemical composition of Eucalyptus maculata, Pinus elliottii and Alstonia scholaris. The differences in lignin composition were different for each timber and discussed in relation to decay caused by soft-rot and white rot fungi. In particular the presence of syringyl and guaiacyl lignin types are discussed.
L E Leightley
An insight into brown rot decay of timber as revealed by 13C CP/MAS NMR
1985 - IRG/WP 1259
L E Leightley
Lignin degradation by wood-degrading fungi
1986 - IRG/WP 1310
The wood-degrading white-rot fungus Phanerochaete chrysosporium, has been the subject of intensive research in recent years and, based upon isolation of the extracelluar enzyme ligninase, major advances have now been made toward elucidating the mechanism by which this fungus degrades lignin. From these developments, a model emerges which could explain the process by which wood-degrading fungi in g...
P J Harvey, H E Schoemaker, J M Palmer
Interaction mechanisms of F/Cr/As/B type preservative and wood
1981 - IRG/WP 3183
The paper reports results of investigations on the fixation of the components of a F/Cr/As/B preservative in wood and its lignin and cellulosic components....
N Ermush, I Andersone
Contribution of wood components on the absorption of copper amine
2000 - IRG/WP 00-30216
The contribution of wood components on the absorption of copper amine was investigated. Holocellulose, lignin and xylan absorbed significant amount of copper. The amount of copper absorbed by cellulose was almost negligible. The removal of extractive also decreased the amount of copper absorption. This study clearly indicates the importance of lignin, hemicellulose in the absorption of copper amin...
D P Kamdem, Jun Zhang
Lignin-copper, a new wood preservative without arsenic and chromium
1992 - IRG/WP 92-3702
A more environmentally sound treatment for wood with preservatives containing no arsenic or chromium, has been developed and studied on a laboratory scale. The method involves a first step impregnation with an aqueous solution containing modified, water-soluble kraft lignin followed by a second step involving impregnation with a copper salt solution to give fixation of the lignin into a water-inso...
B Ohlsson, R Simonson
Immunogold labelling of size marker proteins in brown rot-degraded pine wood
1990 - IRG/WP 1428
Pine wood degraded by Fomitopsis pinicola was infiltrated with a mixture of ovalbumin (45 kDa) and myoglobin (16.7 kDa). After crosslinking of the proteins with glutaraldehyde and preparation for electron microscopy ultrathin sections were labeled with gold-conjugated antibodies. Simultaneous labeling of both proteins on the same section showed that at 50-70% weight loss ovalbumin did not penetrat...
E Srebotnik, K Messner
A novel lipid-related compound, (Z)-1,7-nonadecadiene-2,3-dicarboxylic acid, produced by white-rot fungus Ceriporiopsis subvermispora
2001 - IRG/WP 01-10411
Lipid peroxidation is a possible oxidative process of lignin-degradation at a site far from the enzymes by selective white rot fungi. Production and peroxidation of saturated and unsaturated fatty acids by Ceriporiopsis subvermispora strongly suggests involvement of lipid peroxidation in its ligninolytic system. In this paper, a new aliphatic lipid-related fungal metabolite was isolated from wood ...
M Enoki, Y Honda, M Kuwahara, K Messner, T Watanabe
Spatial arrangement of lignin peroxidase in pine decayed by Phanerochaete chrysosporium and Fomitopsis pinicola
1988 - IRG/WP 1343
By applying immunoelectronmicroscopic methods, lignin peroxidase of the white rot fungus Phanerochaete chrysosporium has been localized in the cytoplasm of hyphae, close to the plasmalemma and on the plasmalemma. Infiltration of wood specimen with culture filtrates, concentrated 300-fold, gave clear information on the penetration of the enzyme into the wood cell wall. Penetration was restricted to...
E Srebotnik, K Messner
Influence of variable lignin content on brown rot decay of wood
1987 - IRG/WP 1320
Compilation of published data and new experiments with brown-rotting fungi on different timber species suggest that their decay activity, in contrast to soft rot and white rot fungi, is not greatly influenced by the type or amount of lignin present....
T Nilsson, G F Daniel
Defining fungal decay types - Final proposal
1988 - IRG/WP 1355
The term soft rot is proposed for all forms of decay caused by Ascomycetes and non-basidiomyceteous Fungi imperfecti. The terms brown rot and white rot should be used only for decay caused by Basidiomycetes. Brown rot is characterized by extensive depolymerization of the cellulose and limited lignin degradation. White rot is characterised by significant degradation of the lignin component in wood....
Involvement of hydrogen peroxide in wood decay by brown-rot and white-rot fungi
1985 - IRG/WP 1256
To gain further understanding of the role of H2O2 in wood degradation by brown- and white-rot fungi, we studied the following: (a) extracellular H2O2 production, (b) effect of various hydroxyl radical (·OH) and singlet O2 (1O2) quenching agents on wood and cellulose degradation, (c) intracellular H2O2 production and catalase activity, and (d) cytochemical localization of H2O2 with diaminobenzidin...
T L Highley, L L Murmanis
Polyflavonoid tannins - From a cause of CCA soft-rot failure to the "missing link" between lignin and microdistribution theories
1986 - IRG/WP 3359
Polyflavonoid tannins are proven to be fast-reacting with CCA solutions and hence, to be strong competitors of the structural wood constituents for fixation of CCA preservatives. The consequence of this effect is that even relatively small amounts of tannin cause severe undertreatment of the structural wood constituents which in turn badly affects the long term durability of CCA-treated timber. Th...
A Pizzi, W E Conradie, M Bariska
Sludge formation in timber treatment with CCA preservatives. Origin and elimination
1984 - IRG/WP 3276
The exact distributions between lignin and holocellulose and retentions on wood of copper, chromium and arsenic as a function of various sets of conditions in a factorial experiment in which combinations of three temperatures of treatment, three CCA solution concentrations, four pH's of the initial CCA solution and two timber species, namely Pinus radiata and Eucalyptus grandis, are repor...
A Pizzi, W E Conradie, A Jansen
Screening of lignin peroxidase from white-rot fungi
1998 - IRG/WP 98-10274
Since lignin peroxidase was first found in the ligninolytic culture of Phanerochaete chrysosporium, it has been regarded as an enzyme responsible for the lignin biodegradation and studied comprehensively. As the results of these studies its unique characteristics have been revealed. On the other hand, the features of lignin peroxidase produced by other white-rot fungi have not been studied so much...
The possible significance of the lignin content and lignin type on the performance of CCA-treated timber in ground contact
1988 - IRG/WP 1357
The lignin in wood samples of Alstonia scholaris, Octomeles sumatrana and a Simaruba species have been analysed. These timbers are characterised by a high lignin content and low syringyl:guaiacyl ratios. Decay tests with two soft rot fungi showed that the timbers were less susceptible than timbers with a low lignin content and higher syringyl:guaiacyl ratios. Numerous data for field performance of...
T Nilsson, J R Obst, G F Daniel
Practical consequences of the clarification of the chemical mechanism of CCA fixation to wood
1983 - IRG/WP 3220
Practical consequences derived from the chemical investigation of the mechanism of fixation of CCA to the wood constituents are discussed. Among these, formulas for the calculation of the time of hexavalent chrome fixation are presented. Furthermore, three parameters are shown to be important to the long-term effectiveness of CCA-treated timber: (i) the temperature of treatment, (ii) the initial p...
UV-microspectrophotometry of lignin and accessory compounds in wood cell walls of conifers
1999 - IRG/WP 99-20171
The distribution of lignin in the cell wall of conifer tracheids was determined by UV-VIS microspectro-photometer. Wood sections of one micron thickness were measured between the wavelength 240 and 700 nm. Spectral analyses revealed that the conifer lignin associated with the tracheid secondary wall and middle lamella is composed of guiacylpropane units which exhibit a characteristic UV absorption...
G Kleist, G Koch, J Bauch
Natural weathering of wood in a sunny climate effects on surface chemistry and paint adhesion
1997 - IRG/WP 97-20109
Radiata pine veneers and blocks were exposed to natural weathering under Australian summer conditions over a period of 30 days. Infrared spectroscopy revealed that there was perceptible surface delignification after 4 hours exposure, substantial surface delignification after 3 days exposure and almost complete surface delignification after 6 days. Viscometry determinations on holocellulose samples...
P D Evans, P D Thay, K J Schmalzl
Reaction of osmium tetroxide with a diphenolic compound as a model substance for demethylated lignin
1986 - IRG/WP 1303
By using caffeic acid as a model substance for diphenolic moieties of demethylated lignin it was found that electron dense particles called by the authors "osmiophilic particles" in former papers are reaction products of OsO4 with the model substance. By these products it is possible to indicate the enzymatic demethylation of lignin taking place during wood decay. The appearance of the electron de...
K Messner, E Srebotnik