Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “WOOD”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed2002

[Asthma from tropical abachi wood].

We report the case of a 28-year old man suffering from rhinitis and asthma which appeared 8 years after exposure to different woods, especially abachi wood. Serial PEFR monitoring at work and away from work were consistent with occupational asthma. Spirometry showed an airway obstruction, and metacholine inhalation test was positive. Skin prick-tests performed with different woods were only positive to abachi wood extract. The search for specific IgE was positive to abachi wood (4, 98 KU/l, class 3). The diagnosis of occupational asthma caused by exposure to abachi wood was established, the mechanism underlying this asthma was IgE mediated. Despite respiratory protection measures, the patient had persisting symptoms and was laid off. The German service for social cover asked for an expert evaluation: specific nasal and inhalation provocation tests performed by exposure to fine abachi wood dust were positive. This is an observation with a double significance: first, although the mechanisms underlying wood occupational asthma remain largely unknown, an IgE mechanism for abachi wood was demonstrated; second, legislation is different in France and Germany where occupational asthma will only be acknowledged if inhalation tests are positive.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Critical analysis of studies concerning reports of respiratory sensitization to certain wood dusts.

Studies have been published reporting that exposures to certain wood dusts are sensitizing, resulting in respiratory symptoms in susceptible individuals. Many of the publications in this field are case reports that collectively have a number of important shortcomings. Illuminating these should further our understanding of whether respiratory sensitization results from occupational exposure to particular wood dusts. The aim of this study was to critically review and understand the evidence to date regarding reported respiratory sensitization in connection with wood dusts from oak, beech, pine, ash, and western red cedar. Publications dealing with these commercially important woods in North America have been selected from the Pubmed/Medline database (1966 to the present) using the key word, wood dust. These articles, along with supporting references on procedures and techniques, are reviewed according to the strengths and weaknesses of evidence and conclusions presented. Evidence from skin testing, specific immunoglobulin E measurements, and basophil histamine release tests suggests that reported symptoms are not likely to be immunologically derived. Because of methodological problems, challenge tests with specific wood dusts do not support the conclusion that reactions to certain wood dusts are specific. Experiments with nonspecific bronchoconstrictive agents indicate that a number of study subjects possess hyperresponsive airways. Thus, select individuals can demonstrate various respiratory symptoms in the woodworking industry, but any specificity or direct cause is currently unproved. Current studies do not support that exposure to wood dusts from a number of common North American wood species causes immunologic sensitization in woodworkers. Rather, symptoms reported in some studies of exposed workers seem to follow the paradigm for nonspecific respiratory responses in individuals with hyperresponsive airways.

Allergens↗
PubMed2004

Ethnobotanical study of fuelwood and timber wood consumption and replenishment in Ogbomoso, Oyo State, Nigeria.

A survey of both urban and rural communities in five Local Government Areas (LGA) of Oyo State in Nigeria showed that 76% of households depend on fuelwood for cooking. The total annual wood consumption for fuelling by bread bakers, food sellers and in domestic cooking was 5984 metric tons for the region. The sawmills in the study area also convert 79 889 metric tons of wood yearly into boards of different grades. Total wood consumption outstrips the quantity of wood extracted from the forests. The balance of over 60 000 metric tons of wood is sourced from neighbouring forest locations. The quantity of wood harvested for various purposes did not show a significant difference (p < 0.05) among the five LGAs. However, a significant difference at p > 0.05 existed in the quantity of wood actually consumed in the various LGAs. Moreover. the number of trees cut down outstrips the number of trees planted with a significant difference (p > 0.05) between the mean quantity of wood removed from the forests and the mean quantity replaced by reforestation. The practice in the study area was that of 'cut-eight-plant-one' which is at variance to the much publicized operation 'cut-one-plant-one'. The study concludes that residents of Ogbomoso in Nigeria have not shown positive disposition to tree planting. It therefore suggests scientific tree conservation strategies aimed at improved burning of fuel wood and maximized use of timber products as complementary efforts to enforced tree planting for conservation of our forests.

Conservation of Natural Resources↗
PubMed1986

Genetic and environmental control of crown development in Picea sitchensis and its relation to stem wood production.

Differences in stem wood production were found among four clones of Picea sitchensis (Bong.) Carr. at both an agricultural and a forest site. Clonal rankings were not consistent between the sites. Four variables were identified that may influence stem wood production, foliage amount, total aboveground production per unit foliage, proportional allocation of production to new foliage and to branch wood thickening. Comparison of clonal performance between sites showed that stem wood production could be influenced by differences in each of these variables. The four variables were themselves determined by components of crown structure, these were (i) production of new branches from the main stem, (ii) the numbers and lengths of branchlets supported on branches from the main stem, (iii) foliage production per unit branchlet length and foliage longevity, and (iv) branch wood thickening per unit branch length. These components varied both among clones and between sites. Branch production from the mainstem varied among clones, and for some clones it varied substantially between sites. In some clones branch production was positively correlated with mainstem height increment. There were differences among clones in the way that branchlet production varied between the agricultural and forest sites. In the absence of needle fall, foliage weight/branch length varied threefold among clones, but for each clone, varied little between sites. Branch wood weight/branch length was generally greater when foliage weight/branch length was large, but total branch wood increment/tree was strongly influenced by total branch length. The dynamics of crown development and its relation to stem wood production are discussed with reference to (i) the importance of needle longevity, (ii) the importance of tallness and narrowness of crowns and (iii) the importance of branch thickening, a process that competes with stem growth in the utilization of photosynthate. It is concluded that although each of these factors may be important, none singly accounts for the observed differences in stem wood production among genotypes and the way these change in response to the environment.

Journal Article↗
PubMed1998

Cancer mortality and wood dust exposure among participants in the American Cancer Society Cancer Prevention Study-II (CPS-II).

In 1994, the International Agency for Research on Cancer (IARC) classified wood duct as a human carcinogen, based on very strong evidence of a carcinogenic risk of sino-nasal cancer. Excesses of other cancers, including lung and stomach, have been reported among persons employed in wood industries or occupationally exposed to wood dust, but not as consistently. We investigated such possible associations using the mortality experience of 362,823 men enrolled in the American Cancer Society's Cancer Prevention Study-II in 1982 and followed up for 6 years. Within this group, 45,399 men (12.5%) reported either employment in a wood-related occupation or exposure to wood dust or both. Among woodworkers, a small but significant excess risk was found for all cases of death (RR 1.17 (95% CI 1.11-1.24)) and for total malignancies (RR 1.17 (1.05-1.30)). Among men who reported exposure to wood dust, there was an elevated risk of total mortality (Rr 1.07 (1.03-1.11)), total malignancies (RR 1.08 (1.01-1.15)), and lung cancer (RR 1.17 (1.04-1.31)). Among woodworkers, a significant trend (P = 0.02) of increasing risk of lung cancer with increasing duration of exposure was observed. An unexpected, significantly increased mortality from prostate cancer was observed in both wood-employed and wood-exposed, and a twofold increased risk of fatal brain cancer was seen among the former. Lung cancer mortality was especially high among woodworkers who also reported exposure to asbestos or formaldehyde, and it appears that exposure to these known carcinogens may partly explain the observed increased risks. Excess sino-nasal cancer was not observed, but the number of cases was small.

Cause of Death↗
PubMed2006

Wood carbon content of tree species in Eastern China: interspecific variability and the importance of the volatile fraction.

Data on the mass density and carbon content of tree organs, and in particular stem wood, are essential for accurate assessments of forest carbon sequestration. However most available data, including that for East Asia, has neglected the volatile C fraction. Wood samples were collected and assayed for C content from 14 native tree species in Jilin Province, NE China. C content showed statistically significant variation among species, ranging from 48.4% to 51.0%. The volatile C fraction was non-negligible, averaging 2.2%, and showed high variation among species. As found in prior studies, wood C content was appreciably higher in conifer than hardwood (angiosperm) species (50.8+/-0.1% vs. 49.5+/-0.2%, respectively). Wood carbon density (gC/cm(3)) showed very high inter-specific variation, due mainly to differences in wood specific gravity. Our analyses, in conjunction with recently published data from North America, indicate a global mean value of 47.5+/-0.5% wood C content exclusive of volatile C; the widely used 50% figure corresponds more closely to total wood C inclusive of the volatile fraction. Failure to include volatile C or to use species- or higher-taxon-specific C content values in forest C assessments is likely to introduce biases on the order approximately 4-6%. In addition, the stocks and flows of the volatile C fraction in wood are in themselves an important and sorely neglected aspect of forest C processes likely to be strongly impacted by harvests and other management practices.

Carbon↗
PubMed2000

Determination of polychlorinated dibenzo-p-dioxins and dibenzo-furans in solid residues from wood combustion by HRGC/HRMS.

PCDD/PCDF were determined in solid samples from wood combustion. The samples included grate ashes, bottom ashes, furnace ashes as well as fly and cyclone ashes. The solid waste samples were classified into bottom and fly ash from native wood and bottom and fly ash from waste wood. For each of the four classes concentration distribution patterns from individual congeners, the sums of PCDD/PCDF and the international toxicity equivalents (I-TEQ) values are given. The I-TEQ levels of fly ash from waste wood burning can be approximately up to two thousand times higher than the values from fly ashes of natural wood. The I-TEQ levels in bottom ashes from waste wood combustion systems are as low as the corresponding ashes from the combustion of native wood. Grate ash samples from waste wood combustion systems with low carbon burnout show high levels of PCDD/PCDF.

Benzofurans↗
PubMed2003

Toxicity assessment of wood preservatives.

The article describes the influence of wood preservatives on water bioceonosis. The "battery" of toxicology tests was used to cover luminescent bacteria test, algae growth inhibition test, crustacean and fish lethal tests. The test samples used were pure wood preservative and water after the wood preservative leaching from wood sample. It was observed that the wood preservative is leaching from the wood sample in 10% within 1 month of exposition. Achieved results indicate the necessity of toxic assessment of wood preservative after wood element protection.

Animals↗
PubMed2002

Moisture excluding efficiency and dimensional stability of wood improved by acylation.

The dimensional stability and moisture excluding efficiencies (MEEs) of wood after acetylation, butyrylation, and hexanoylation, were evaluated in this study. After three acylation treatments, an excellent antiswelling efficiency of modified wood specimens was obtained. All the equilibrium moisture contents of acylated wood at three relative humidities (RHs) (33% RH, 65% RH, and 93% RH) were significantly reduced, as compared to those of untreated wood in the same RH, and the MEEs of acylated wood were greatly improved. Acylated wood has consistent MEE at each of the different RHs. With the same percentage of substituted hydroxyl groups, the decreasing order of the MEE of modified wood was hexanoylation > butyrylation > acetylation. This indicates that the molecular volume or hydrophobic property of the substituted acyl groups also has the influence on the MEE of modified wood, in addition to the degree of substitution of the hydroxyl groups.

Acer↗
PubMed2002

Effect of wood ash application on soil solution chemistry of tropical acid soils: incubation study.

The objective of this study was to determine the effect of wood ash application on soil solution composition of three tropical acid soils. Calcium carbonate was used as a reference amendment. Amended soils and control were incubated for 60 days. To assess soluble nutrients, saturation extracts were analysed at 15 days intervals. Wood ash application affects the soil solution chemistry in two ways, as a liming agent and as a supplier of nutrients. As a liming agent, wood ash application induced increases in soil solution pH, Ca, Mg, inorganic C, SO4 and DOC. As a supplier of elements, the increase in the soil solution pH was partly due to ligand exchange between wood ash SO4 and OH- ions. Large increases in concentrations of inorganic C, SO4, Ca and Mg with wood ash relative to lime and especially increases in K reflected the supply of these elements by wood ash. Wood ash application could represent increased availability of nutrients for the plant. However, large concentrations of basic cations, SO4 and NO3 obtained with higher application rates could be a concern because of potential solute transport to surface waters and groundwater. Wood ash must be applied at reasonable rates to avoid any risk for the environment.

Calcium↗
PubMed2002

Chemical characterzation of fine particle emissions from the fireplace combustion of woods grown in the Southern United States.

The fireplace combustion of wood is a significant and largely unregulated source of fine particle pollution in the United States. Source apportionment techniques that use particulate organic compounds as tracers have been successful in determining the contribution of wood smoke to ambient fine particle levels in specific areas in California. To apply these techniques to the rest of the United States, the differences in emissions profiles between different wood smoke sources and fuel types should be resolved. To this end, a series of fireplace source tests was conducted on six fuel wood species found in the Southern United States to determine fine particulate emission factors for total mass, ionic and elemental species, elemental and organic carbon, and over 250 individual organic compounds. The wood species tested, chosen for their high abundance and availability in the Southern U.S. region, were yellow poplar, white ash, sweetgum, mockernut hickory, loblolly pine, and slash pine. The differences in the emissions of compounds such as substituted phenols and resin acids help to distinguish between the smoke from hardwood and softwood combustion. Levoglucosan, a cellulose pyrolysis product which may serve as a tracer for wood smoke in general, was quantified in the emissions from all the wood species burned. The furofuran lignan, yangambin, which was emitted in significant quantities from yellow poplar combustion and not detected in any of the other North American wood smokes, is a potential species-specific molecular tracer which may be useful in qualitatively identifying particulate emissions from a specific geographical area where yellow poplar is being burned.

Air Pollutants↗
PubMed2004

Chemical structure of arsenic and chromium in CCA-treated wood: implications of environmental weathering.

Chromated copper arsenate (CCA) has been used to treat lumber for over 60 years to increase the expected lifetime of CCA-treated wood. Because of the toxicity of the arsenic and chromium used in CCA treatment, regulatory and public attention has become focused on the potential risks from this exposure source. In particular, exposure of children to arsenic from CCA-treated wood used in decks and play sets has received considerable attention. X-ray Absorption Spectroscopy (XAS) was used to evaluate the chemical structure of As and Cr in three samples of CCA-treated materials: newly treated wood, aged wood (5 years as decking), and dislodgeable residue from aged (1-4 years as decking) CCA-treated wood. The form of the Cr and As in CCA-treated material is the same in fresh and aged samples, and between treated wood and dislodged residue. In all cases, the dominant oxidation state of the two elements is As(V) and Cr(III), and the local chemical environment of the two elements is best represented as a Cr/As cluster consisting of a Cr dimer bridged by an As(V) oxyanion. Long-term stability of the As/Cr cluster is suggested by its persistence from the new wood through the aged wood and the dislodgeable residue.

Arsenates↗
PubMed2006

Sorption of PAHs by aspen wood fibers as affected by chemical alterations.

Sorption and desorption experiments for phenanthrene and pyrene, using untreated (UTR) and treated (bleaching and hydrolysis) aspen wood fibers, were examined to understand their sorption mechanisms. The wood was characterized by elemental and porosity analysis, solid-state 13C NMR, and diffuse reflectance infrared Fourier transform spectroscopy. Bleaching removed aromatic components, yielding the highest polarity and increased porosity, whereas hydrolysis removed a large percentage of hemicellulose and parts of amorphous cellulose, producing a matrix with more aromatic moieties, lower polarity, and higher porosity than that of the UTR wood fibers. All isotherms fitted well to the Freundlich equation and the N values had a decreasing trend from bleached (BL), UTR, low-temperature hydrolyzed to high-temperature hydrolyzed (HHY) wood fibers. BL fibers had the lowest sorption capacity (Koc) for both phenanthrene and pyrene. HHY had the highest Koc because of its high aromatic carbon content and low polarity. The results suggest that aromatic moieties and polarity of wood fibers play significant roles in polycyclic aromatic hydrocarbon (PAHs) sorption and desorption. Thus, both aromatic components and polarity should be considered when predicting the PAHs sorption/desorption by aspen wood fibers. This study demonstrated that aspen wood fibers are a potential sorbentfor PAHs and that chemical modifications of the wood matrix can effectively increase its sorption efficiency. These results may have implications for the treatment of stormwater runoff and other PAH-contaminated liquids.

Cellulose↗
PubMed2003

Volatile compounds in a spanish red wine aged in barrels made of Spanish, French, and American oak wood.

A red Rioja wine was aged in barrels made of Spanish oak wood (Quercus robur, Quercus petraea,Quercus pyrenaica, and Quercus faginea) during 21 months. The concentrations of some volatile compounds [syringaldehyde, vanillin, eugenol, maltol, guaiacol, 4-ethylphenol, cis and trans isomers of beta-methyl-gamma-octalactone, 2-furfuraldehyde, 5-methyl-2-furfuraldehyde, 5-(hydroxymethyl)-2-furfuraldehyde, and furfuryl alcohol] were studied in these wines and compared with those of the same wine aged in barrels made from French oak of Q. robur (Limousin, France) and Q. petraea (Allier, France) and American oak of Quercus alba (Missouri). Similar concentrations of these compounds were found in wines aged in Spanish and French oak wood barrels, and significantly different concentrations were found with respect to wines aged in barrels made of American oak wood, indicating a different behavior. Thus, wines with different characteristics were obtained, depending on the kind of wood. Also, the kind of wood had an important influence on sensory characteristics of wine during the aging process. Spanish oak wood from Q. robur, Q. petraea, and Q. pyrenaica can be considered to be suitable for barrel production for quality wines, because a wine aged in barrels made of these Spanish oak woods showed similar and intermediate characteristics to those of the same wine aged in French and American oak woods usually used in cooperage.

Food Handling↗
PubMed2003

Novel gene expression profiles define the metabolic and physiological processes characteristic of wood and its extractive formation in a hardwood tree species, Robinia pseudoacacia.

Wood is of critical importance to humans as a primary feedstock for biofuel, fiber, solid wood products, and various natural compounds including pharmaceuticals. The trunk wood of most tree species has two distinctly different regions: sapwood and heartwood. In addition to the major constituents, wood contains extraneous chemicals that can be removed by extraction with various solvents. The composition and the content of the extractives vary depending on such factors as, species, growth conditions, and time of year when the tree is cut. Despite the great commercial and keen scientific interest, little is known about the tree-specific biology of the formation of heartwood and its extractives. In order to gain insight on the molecular regulations of heartwood and its extractive formation, we carried out global examination of gene expression profiles across the trunk wood of black locust (Robinia pseudoacacia L.) trees. Of the 2,915 expressed sequenced tags (ESTs) that were generated and analyzed in the current study, 55.3% showed no match to known sequences. Cluster analysis of the ESTs identified a total of 2278 unigene sets, which were used to construct cDNA microarrays. Microarray hybridization analyses were then performed to survey the changes in gene expression profiles of trunk wood. The gene expression profiles of wood formation differ according to the region of trunk wood sampled, with highly expressed genes defining the metabolic and physiological processes characteristic of each region. For example, the gene encoding sugar transport had the highest expression in the sapwood, while the structural genes for flavonoid biosynthesis were up-regulated in the sapwood-heartwood transition zone. This analysis also established the expression patterns of 341 previously unknown genes.

DNA, Complementary↗
PubMed2005

On-filter determination of collected wood dust by diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS).

A new analytical technique based on DRIFTS spectroscopy has been developed for the specific and sensitive determination of size-fractionated wood dust from 37 mm glass fiber filter samples collected with the Respicon sampler. A translational diffuse reflectance apparatus was modified to accept filter samples by incorporating a special filter holder in the sample stage and a clockwork motor to drive the translational stage during infrared scanning, thus providing an average analysis across the filter face. Filter samples were pre-treated with ethyl acetate to uniformly redeposit dust onto the filter and extract potential chemical interferences. Two absorbance maxima (1251 and 1291 cm(-1)), corresponding to the cellulose content of the wood, were suitable for quantitation of wood dust. Analysis of seven species of wood at 1291 cm(-1) showed an equivalent quantitative response for all species except maple. The response at 1251 cm(-1) was more variable across species but more sensitive for the softwoods. There was a statistically significant effect of particle size on the analytical response, so that analytical standards should be matched to the samples in terms of particle size distribution. Analytical limit of detection was approximately 0.08 mg of wood dust per sample with overall precision of about 6%. Comparison of DRIFTS and gravimetric analyses of 51 pure wood dust samples ranging from about 0.2 to 2 mg yielded a slope of 1.08 and r2 equal to 0.9. Other particulate contaminants common in the industrial wood processing industry showed little or no interference with the determination of wood dust by this method.

Air Pollutants, Occupational↗
PubMed2001

Wood stove heating, asthma and allergies.

In two German studies household wood or coal stove use was negatively associated with atopic sensitization and allergic rhinitis in childhood. Wood stove heating is strongly related to 'traditional lifestyle and therefore subjected to confounding factors possibly yet not known. The study was conducted to study these factors and the independent impact of early exposure to wood stove heating on subsequent asthma and atopic disease. In a questionnaire survey among 10667 Finnish university students aged 18-25 years, we investigated the association between wood stove heating at age 0-6 years and asthma and allergies up to young adulthood. Adjustment was made for factors related to the heating system and atopic disorders by using multivariate regression. Unadjusted lifetime prevalence rates for physician-diagnosed asthma, allergic rhinoconjunctivitis, atopic dermatitis and self-reported wheezing were lower among subjects with wood stove heating compared to other heating systems. There was a significant negative association between childhood wood stove heating and allergic rhinitis or conjunctivitis in the univariate model (OR 0.61, 95% CI 0.61-0.91), but not for the other diseases. The significant association disappeared in the multivariate analysis after adjusting for various family indoor and outdoor (adjusted OR 0.96, 95% CI 0.77-1.20) factors. The association between wood stove heating and allergic rhinoconjunctivitis was mainly confounded by childhood residential environment, especially the farm environment. Farm environment was found to be the main confounding factor related to association between wood stove heating and asthma, and atopic diseases.

Adolescent↗
PubMed1994

Level and distribution of employee exposures to total and respirable wood dust in two Canadian sawmills.

Personal respirable (N = 230) and total (N = 237) dust measurements were made in two coastal British Columbia sawmills using a sampling strategy that randomly selected workers from all jobs in the mills over two seasons. Information about job title, department, season, weather conditions, location of the job relative to wood-cutting machines, and control measures also was collected at the time of sampling. Only 16 respirable wood dust samples were above the detection limit of 0.08 mg/m3; all 16 had levels < or = 0.20 mg/m3. Total wood dust concentrations were also low (36% less than the detection limit), with a mean of 0.51 mg/m3, and ranging from < 0.08 to 52 mg/m3. Measurements of exposure taken close to chippers, planers, and multiple saws had the highest total wood dust levels. Sawmill department and booth enclosures also were associated with wood dust concentrations, while local exhaust ventilation and weather conditions were not. Wood dust levels in this study were generally lower than in other studies of this industry, but most sawmill investigations report mean wood dust concentrations lower than those measured in the furniture and cabinetmaking industries, where concerns about wood dust exposures initially were raised.

British Columbia↗