Your search resulted in 69 documents. Displaying 25 entries per page.
Antifungal mechanism of dichloro-N-octylisothiazolone
1998 - IRG/WP 98-30183
4,5-dichloro-N-octylisothiazolin-3-one (DCOI) is a member of the isothiazolone class of preservatives, whose antimicrobial mechanism of action has been intensively studied over the last decade. DCOI has also been intensively studied for use in wood preservation. The isothiazolones are electrophilic molecules that rapidly react with thiol groups to form covalently bonded isothiazolone-thiol adducts. This ability to bond with thiol groups is crucial to their ability to act as preservatives. Thiol groups are present in proteins as part of the amino acid cysteine, where they play an important role in maintaining protein structure and function. A number of enzymes have thiol groups at the site where the enzyme function is performed, and these thiol groups may participate in the enzyme reaction. If the isothiazolone reacts with this thiol group, the activity of the enzyme is inhibited. Our studies have shown that there are several enzymes in the Krebs cycle that are inhibited by isothiazolones and these enzymes are required to generate energy and perform many biosynthetic functions. Reflective of this, DCOI has been shown to be a rapid inhibitor of cellular respiration, causing the cell to cease consuming oxygen almost immediately upon contact with DCOI. The multiplicity of targets and their central importance to the metabolism of the cell, as well as the fact that all microbes use at least parts of the Krebs cycle, can be related to the low use levels and broad spectrum of activity of DCOI. The antimicrobial mechanism of DCOI results in a potent rapid-acting preservative with a broad spectrum of antifungal and antibacterial activity that is effective at low levels.
J S Chapman, M A Diehl, K B Fearnside, L E Leightley
The probable mechanism of action of boric acid and borates as wood preservatives
1990 - IRG/WP 1450
The tetrahydroxyborate ion [B(OH)4-] acts by complexation with poly-ols and probably attacks decay fungi through extracellular substrate sequestration; intracellular substrate sequestration; enzyme inhibition; and change in membrane function. Work was carried out to investigate this further and to try to explain certain phenomena observed in the area of boron preservation. The effect of Na borate ...
J D Lloyd, D J Dickinson, R J Murphy
A new concept of oxalic acid biosynthesis in physiology of copper-tolerant brown-rot fungi
2001 - IRG/WP 01-10394
Recently, a wide variety of roles of oxalic acid (oxalate) in wood decay systems have been receiving much attention. Copper tolerance of wood-rotting basidiomycetes has been believed to be due to the detoxification of copper wood preservatives by oxalate produced by these fungi. However, biochemical mechanism of oxalate biosynthesis in relation to physiology of wood-rotting fungi has not been eluc...
E Munir, T Hattori, M Shimada
Comparative evaluation of the barrier effect against Hylotrupes bajulus L. of different types of wood preservative
1986 - IRG/WP 1307
This paper settles the difference of contact action against females of Hylotrupes bajulus the likelihood of egg-laying, the ovicide effect and the hazards of development of newly hatched larvae between some preservatives belonging to three differents types: mineral waterborne products, organic products and emulsions. The results show that against females, the action is fast with organic products, ...
Preventive action against fungal decay: A comparative experiment on the effects of natural and artificial infection of wood by Basidiomycetes
1981 - IRG/WP 2160
Bacteria and wood. A review of the literature relating to the presence, action and interaction of bacteria in wood
1971 - IRG/WP 101
S E Rossell, E G M Abbot, J F Levy
Report on the questionnaire sent out to IRG Members for the creation of a new Sub-group 4 "evaluation of superficial treatments for preventive action against basidiomycetes"
1992 - IRG/WP 92-2417
On Thuesday May 12th, 1992 a subgroup meeting was held between 16.00-17.00 h. About 50 people attended this meeting. The results of the questionnaire sent out last year to the IRG members, was discussed. The analysis as well as the practical conclussions of the discussions are retained in this document....
A R Valcke
Copper binding capacity of modified wood flour
1992 - IRG/WP 92-3709
Wood flour was modified by reaction with oxidising agents and CCA preservative. The copper chromium and arsenic were removed from the CCA treated wood flour by an acid leaching procedure. The modified wood flours were allowed to react with copper acetate solution and the level of copper fixation achieved was determined. The modified wood flours had greater affinity for copper ions present in solut...
N C Milowych, W B Banks, J A Cornfield
Effect of methylene bisthiocyanate on morphology and ultra-structure of a sapstain fungus, Ophiostoma floccosum
2003 - IRG/WP 03-10471
In vitro effects of methylene bisthiocyanate (MBT) on hyphal morphology and ultrastructure of Ophiostoma floccosum were examined using differential interference contrast, epifluorescence and transmission electron microscopy (TEM). Differential interference contrast microscopy suggested that MBT caused rapid changes to the morphology of O. floccosum resulting in excessive formation of vacuoles and...
T Singh, B Kreber, R N Wakeling, A Stewart
Sustainability Through New Technologies for Enhanced Wood Durability. COST Action E37 – A New Action in the Forestry Domain
2004 - IRG/WP 04-40293
The main overall objective of the action is to concentrate on the contribution of wood durability on the sustainability through the development of systems for quality assurance and perfoamance of modified wood and wood products as alternatives to wood treated with traditional preservatives. By this means it seeks to improve and consequently increase the cost-effective use of sustainably produced E...
Vapour boron treatment of wood based panels: Mechanism for effect upon impact resistance
1994 - IRG/WP 94-40036
Samples of medium density fibreboard, chipboard and oriented strandboard (OSB) were treated to two retentions of boric acid by a vapour phase treatment. The results of a range of mechanical tests were reported by Hashim et al. (1992, 1993) in which a small reduction in impact resistance was observed. Several investigations were carried out to study how and where this loss in impact resistance occu...
R Hashim, R J Murphy, D J Dickinson, J Dinwoodie
The development of a screening method for the activity of pyrethroids against wood boring marine crustaceans, Limnoria spp
1978 - IRG/WP 443
The present work is concerned with the develepment of a suitable bio-assay technique to determine the biological activity (contact action) of pyrethroids against Limnoria spp. Estimates of the toxicity of three pyrethroids, permethrin, cypermethrin and decamethrin (the structures of which are shown in Fig. 1.) to the marine borer have been obtained....
D Rutherford, R C Reay, M G Ford
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...
Building With Wood an strategic action in Spain
2010 - IRG/WP 10-40530
This paper explains the objectives and results of the “Building with Wood” project, mainly at Spanish level. As far as the wood preservation field is concerned, the present abstract also informs about the main goals of the project in this matter....
M Conde García, J I Fernández-Golfín Seco, J Galván Rodríguez
The effect of wick action on the moisture distribution in heartwood and sapwood stakes of Pinus radiata D. Don.
1999 - IRG/WP 99-40139
The pattern of moisture distribution in stakes of Pinus radiata D. Don. subjected to "wick action" is investigated. There was incomplete saturation of the stakes even after 93 days of continual soaking. Maximum moisture absorption occurred at the base of the stake and at the air/water interface of the stake. Incomplete saturation of the stake was thought to be due to air embolism within the wood. ...
J Hann, P Vinden
Preliminary studies of the decay mechanism of some brown-rot fungi
1989 - IRG/WP 1402
The importance of the enzymatic degradation of hemicellulose and cellulose by brown-rot fungi is still under discussion. Endo-ß-1,4-xylanase and endoglucanase activities of Coniophora puteana and Poria placenta cultures were measured by the increase in reducing groups. Enzymes were produced in liquid and solid sawdust based culture media. Enzyme activities were measured in two, four and eight wee...
A-C Ritschkoff, H Viitanen
An attempt to develop a direct and reliable method for testing the preventive action of preservation treatments of wood against fungal decay
1980 - IRG/WP 2139
In wood preservation there are two classical ways for assessing the reliability of preventive treatments against wood decay: the laboratory tests in which the various parameters are evaluated independently and the field tests or service tests in which those parameters are acting together in the natural environment. One has always tried to build bridges between the two types of experiments and to e...
The mechanism of leaching of copper-chrome-arsenic preservatives from treated timber in saline waters
1976 - IRG/WP 374
A mechanism for the leaching of copper-chrome-arsenic preservatives is proposed on the basis of theoretical calculations and experimental studies using timber subjected to a range of water types of different ionic compositions. Complex formation by copper (II) and chromium (III) with chloride and hydroxide ions is shown to affect the leaching rate. Of even greater importance is the salt effect on ...
J Irvine, S-E Dahlgren
Studies on the resistance of DMDHEU treated wood against white-rot and brown-rot fungi
2005 - IRG/WP 05-10566
Beech wood (Fagus sylvatica) modified with the textile finishing agent 1,3 dimethylol-4,5-dihydroxyethylen urea (DMDHEU) has shown to improve durability against the white-rot fungus Trametes versicolor. In a mini-block test, the weight loss over eight weeks of incubation decreased with increasing weight percent gain (WPG) of DMDHEU. At 25% WPG, no significant weight loss was observed, while untrea...
P Verma, C Mai, A Krause, H Militz
Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part 5: Effect of wood species and preservative composition on the leaching during storage
1975 - IRG/WP 354
Conversion reactions during storage of CCA treated wood take place even at and below the fiber saturation point as long as ion transport is possible. Increase in drying temperature increases the final pH of the treated wood and the leachability of Cu and decreases slightly the leachability of Cr, while the leachability of As is not affected. This temperature effect is considered to be of no techni...
The degradation of wood by metal fastenings and fittings
1972 - IRG/WP 302
As well as the hazards of biological decay, timber used in boat building is subject to the effects of chemical decay associated with the corrosion of metallic fastenings. The title has been deliberately chosen to emphasize that in wooden construction the troubles are not just those of corrosion of the fastenings, but also the destructive secondary effects on the wood caused by the products of the ...
L C Pinion
Advances in understanding the mode of action of methylene bisthiocyanate against Sphaeropsis sapinea
2002 - IRG/WP 02-30284
The importance of arresting sapstain pre-infection in radiata pine in New Zealand, to prevent downstream sapstain in both logs and sawn timbers has been clearly demonstrated. Efforts are being made to improve the efficacy of diffusible antisapstain agents through improved understanding wood/fungicide/fungus interactions. The mechanism of action of methylene bisthiocyanate (MBT) was investigated u...
T Singh, R N Wakeling, B Kreber, A Stewart
The effect of chemical treatment on the moisture distribution of Pinus radiata D.Don subjected to wick action
1999 - IRG/WP 99-40135
Radiata pine sapwood stakes were treated with a range of chemicals, including an ammoniacal copper quaternary ammonium compound (ACQ), a copper-chrome and arsenic (CCA) solution and a CCA-oil treatment, potassium linoleate copper linoleate, a paraffin wax and a proprietary alkyd resin. The effect of these treatments on the extent of water absorption and moisture movement through the stakes was inv...
J Hann, P Vinden
Corrosion of fasteners in treated wood
1971 - IRG/WP 303
Surveying tests for determining the corrosion rates of some metals and alloys in wood untreated as well as treated have been made. It is shown that ordinary steel corrodes faster than other common fastener metals such as copper, brass, aluminium and stainless steel do. Zinc coatings, however, will prevent the steel corrosion effectively provided that the coatings are thick sufficiently. Catalytic ...
Kinetics and mechanism of fixation of Cu-Cr-As wood preservatives. Part 6: The length of the primary precipitation period
1975 - IRG/WP 359
The end of the primary precipitation fixation period of CCA preservatives coincides with the first peak in pH versus time. This offers a simple way of estimating the duration of the period. The duration is determined by a number of factors and their interactions, the most important of which are: wood species (anatomy, natural pH, accessibility of reducing agents), preservative type, preservative c...