bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction of Resin Pockets in Seedlings of Pinus sylvestris L. by Mechanical Bending Stress during Growth
Authors: Temnerud Erik , Valinger Erik , Sundberg Björn 
Published: October 2004

Summary
Mechanical bending stress due to wind exposure has been suggested to be of major importance for
induction of resin pockets in gymnosperm trees. In this study, this idea was tested experimentally by
applying bending stress to 1-year-old internodes of five-year-old Pinus sylvestris L. seedlings during
dormancy and/or growth. The stems were bent manually to 30° from their original upright position at
regular intervals. About 30% of the stems that were bent during growth were wounded in the xylem,
whereas no wounding was observed in control stems or stems bent during dormancy. Similarity of these
wounds to naturally-occurring resin pockets leads us to conclude that exposure of seedlings to
mechanical bending stress due to wind during growth can be a source of formation of resin pockets.
Glyceryl-Acyl and Aryl-Acyl Dimers in Pseudotsuga menziesii Bark Suberin
Authors: Graça José , Pereira Helena 
Published: October 2004

Summary
The cork from the outer bark of Douglas-fir (Pseudotsuga menziesii) was exhaustively extracted and
submitted to a mild CaO-catalyzed methanolic depolymerization. The solubilized material (2.5 % yield)
was derivatized and analysed with GC-MS. Glycerol was the main component (41.2%), followed by
aliphatic acid monomers (30.6%) and glyceryl and feruloyl dimers (14.5%). Monoacylglyceryl esters
of α,ω-diacids were dominant (68% of glyceryl dimers), followed by monoacylglyceryl esters of
alkanoic acids and of ω-hydroxyacids (respectively 20% and 9%). For all cases 1- and 2-monoacyl-glyceryl
esters were present. Dimers of ω-hydroxyacids esterified to ferulic acid through their primary
hydroxyl were also found. The feruloyl ester of docosanol could also be identified. The relative
abundance of the dimers followed the proportion of acid monomers. The direct evidence found here
for P. menziesii, and previously for Q. suber, that glycerol is esterified to all suberinic acids and that
ω-hydroxyacids are esterified to ferulic acid supported the discussion of a suberin structure developing
on glyceryl-diacyl-glyceryl and glyceryl-hydroxyacyl-feruloyl backbones.
A New Mechanism in the Ozone Reaction with Lignin Like Structures
Authors: Ragnar Martin , Eriksson Tord , Reitberger Torbjörn , Brandt Peter 
Published: October 2004

Summary
A new mechanism including a homolytic cleavage of a trioxide intermediate forming superoxide is
suggested to be the main course of radical formation in reactions of ozone and lignin like structures.
The suggested mechanism is supported by quantum chemical and thermochemical methods.
The Mechanisms Behind the Improved Dimensional Stability of Particleboards Made from Steam-Pretreated Particles
Authors: Sekino Noboru , Inoue Masafumi , Irle Mark , Adcock Tim 
Published: October 2004

Summary

The mechanisms which cause an improvement in the dimensional stability of particleboards made from
steam pretreated particles were investigated from the aspects of potential thickness recoveries of
densified wood particles and the breakage of the adhesive bond network in particleboards. Since the
latter would depend on the balance between bond strengths and stresses imposed on the adhesive bond,
the effects of steaming temperature (160 to 220°C) on bond quality, recovery stress of compressed
wood and in-plane swelling stress were investigated. Steam pretreatment was found: 1) to reduce
thickness recoveries of densified wood particles, steaming temperatures above 190°C are especially
effective, 2) not to cause a significant reduction in bond strength when steaming below 210°C or if
relatively high press pressures of 1.5MPa are employed, 3) to reduce recovery stress of compressed
wood, which is mainly caused by the increase in wood compressibility, 4) to reduce in-plane swelling
stress of particles, which was found to correlate with reductions in both hygroscopicity and elasticity.
The Thermomechanical Behaviour of Wood Subject to Fungal Decay
Authors: Birkinshaw C. , McCarthy C.J. , Regan N. , Hale M.D.C. , Cahill D. , McCourt M. 
Published: October 2004

Summary
Specimens of Pinus sylvestris have been subject to decay by the brown rot fungus Coniophora puteana, the white rot fungus Phanerochaete chrysosporium, and to doses of γ irradiation sufficiently high to cause significant molecular damage. Specimens of Picea abies have been subject to decay by the brown rot fungus Postia placenta. The dynamic mechanical properties of the decayed and degraded materials have been assessed between −100 °C and 120 °C using in some cases a natural frequency instrument and in other cases a driven frequency instrument. The results obtained have allowed calculation of the temperature coefficients of modulus for the materials at various stages of decay or degradation, and these are relatively constant regardless of the history of the specimen. Such changes as do occur can be explained by modulus dependent frequency effects. The static mechanical properties of some specimens were also assessed by three point bending at 20 °C. Measured changes in dynamic stiffness and flexural modulus have been compared with the weight changes and the proportionality constant relating strength and stiffness loss to weight loss obtained for each situation. These show that in the case of fungal attack the dynamic stiffness falls more quickly than flexural strength, and that, as would be expected, the brown rot fungi are the more effective at reducing mechanical properties.
Investigations into Laccase-Mediator Delignification of Kraft Pulps
Authors: Sealey J. , Ragauskas A.J. , Elder T.J. 
Published: October 2004

SummaryThe structure activity effects of 1-hydroxy benzotriazole and phthalimide derivatives as mediators for laccase were studied. Using a softwood kraft pulp it was shown that the N-hydroxy unit is a key component of 1-hydroxybenzotriazole for efficient laccase mediator delignification to occur. It was also found that the 1-hydroxybenzotriazole structure was very sensitive to substituent effects with respect to laccase-mediator delignification. Computational results from PM3 indicate that the bond dissociation energy, and electronic factors of the radical may contribute to the efficiency of the mediator for LMS delignification.
Cell-Wall-Associated Oxidases from the Lignifying Xylem of Angiosperms and Gymnosperms: Monolignol Oxidation
Authors: Deighton Nigel , Richardson Andrew , Stewart Derek , McDougall Gordon J. 
Published: October 2004

Summary
Cell-wall-associated oxidases extracted from the lignifying xylem of Sitka spruce and ash oxidise sinapyl alcohol at a greater rate than coniferyl alcohol and p-coumaryl alcohol (SA > CA > pCA). The enzyme from ash shows a marked preference, on a specific activity basis, for the oxidation of SA over CA and pCA (SA ≫ CA ≥ pCA) and has a particularly low affinity for the oxidation of coniferyl alcohol compared to the enzyme from spruce (SA > CA > pCA). This difference in monolignol preference between the spruce and ash enzymes may relate to their required functions during lignification, in that the hardwood enzyme would be supplied mainly SA and the softwood enzyme would be supplied mainly CA. The spruce enzyme also displayed a marked preference for the oxidation of sinapyl alcohol over sinapyl aldehyde even when the two compounds were presented in a mixture.
Purified cell walls from the lignifying xylem of spruce could oxidise CA by the action of bound oxidase activity and dissolved oxygen (~ 240 μM) but CA oxidation was increased many fold by the action of the bound peroxidase activity and 240 μM H2O2. However, the initial dimeric and trimeric products of the peroxidase- and oxidase-catalysed reactions detected by liquid chromatography-mass spectrometry were the same and present in similar proportions. This indicates that the oxidation of CA by oxidase or by peroxidase proceeds via the same intermediates and occurs by a similar mechanism.
Insoluble dehydrogenation polymers (DHPs) of CA were formed in similar yields by spruce extracts in the absence (oxidase activity) or presence (peroxidase activity) of H2O2. The peroxidase-catalysed DHPs and the oxidase-catalysed DHPs gave Fourier transform infra-red spectra with maxima that were characteristic of DHPs of CA. However, differences in the comparative intensities of some maxima suggest that the oxidase-catalysed DHPs were less condensed than the peroxidase-catalysed polymers. These findings are discussed with respect to the possible contribution of oxidases to lignin structure in developing wood.
Atmospheric Acetic Acid Pulping of Rice Straw IV: Physico-Chemical Characterization of Acetic Acid Lignins from Rice Straw and Woods. Part 1. Physical Characteristics
Authors: Pan Xue-Jun , Sano Yoshihiro 
Published: October 2004

Summary
Lignins obtained by atmospheric acetic acid delignification of rice straw, birch and fir were characterized by molecular weight, solubility and thermomechanical analysis, and by ultraviolet (UV), Fourier transform infra-red (FTIR) and 13C-NMR spectroscopy. Rice straw lignins (rice lignins) were very different from birch and fir lignins. The former was difficult to dissolve in most tested solvents and infusible on heating, while the latter had a good solubility and fusibility. FTIR spectra indicated that the rice lignins had more conjugated and fewer unconjugated carbonyl groups than the wood lignins. 13C-NMR spectra showed that rice lignins had more polysaccharides associated to the lignin and more p-coumaric and ferulic acid than the wood lignins. Concentrations of acetic acid and choice of catalyst (sulfuric or hydrochloric acid) had a considerable effect on the characteristics of rice lignins. Rice lignin obtained with 90% acetic acid than that obtained with 80% acetic acid, and the lignin obtained with sulfuric acid as catalyst than that obtained with hydrochloric acid, had lower molecular weight, better solubility, lower glass-transition temperature and lower UV absorptivity. 80% acetic acid delignified rice straw less effectively than 90% acetic acid.
Stress Relaxation of Sugi (Cryptomeria japonica D.Don) Wood in Radial Compression under High Temperature Steam
Authors: Dwianto W. , Morooka T. , Norimoto M. , Kitajima T. 
Published: October 2004

Summary
To clarify the mechanism of the permanent fixation of compressive deformation of wood by high temperature steaming, stress relaxation and stress-strain relationships in the radial compression for Sugi (Cryptomeria japonica D.Don) wood were measured under steam at temperatures up to 200°C. The stress relaxation curves above 100°C were quite different in shape from those below 100°C, showing a rapid decrease in stress with increasing temperature. In the stress-strain relationships measured above 140°C, the stress reduced as pre-steaming time increased when compared at the same strain. The recovery of compressive deformation (strain recovery) was decreased with steaming time and reached almost 0 in 10 min at 200°C. The relationship between the residual stress and the strain recovery at the end of relaxation measurements could be expressed by a single curve regardless of time and temperature. The permanent fixation of deformation by steaming below 200°C was considered to be due to chain scission of hemicelluloses accompanying a slight cleavage of lignin. In some cases, the increase in regularity of the crystalline lattice space of microfibrils or the formation of crosslinks between the cell wall polymers seemed to play an important role in the permanent fixation of compressive deformation.
Structural Performance of Fire-Retardant Treated Plywood: Effect of Elevated Temperature
Authors: Wang Song-Yung , Rao Yu-Chen 
Published: October 2004

Summary
This paper was designed to investigate the change of bending strength, bonding shear strength and surface fire-retardant (FR) performance of FR treated plywood after accelerated degradation treatment at elevated temperature (77 °C) and medium humidity (50%RH) condition. Furthermore, thermogravimetry analysis (TGA) and differential scanning curves (DSC) analysis were also conducted to explore their thermal degradation. PF-bonded Red meranti (Shorea spp.) and radiata pine (Pinus radiata) plywood, FR chemicals of AF21 and Lee-An 302 were used.
Results indicated that the bending strength and bonding shear strength of non-FR treated and FR treated plywood decreased linearly with the increase of treatment durations. After 80 days of accelerated degradation treatment, the reduction ratio ( %) of bending strength ranged from 6.5% to 33.4% and varied with treatment conditions, whereas 12.8% to 42.3% reduction ratios were observed in bonding shear strength. After subjected to accelerated degradation treatment FR treated plywood could meet the requirement of the third grade FR performance as specified by CNS 6532 standard except those treated with Lee-An 302 FR for 20 days and 40 days. Furthermore, based on TGA, the weight loss of FR treated plywood was found to be less than that of non-FR treated plywoods. After thermal degradation under 100°C, the residual weight of FR treated plywood was higher than that of non-FR treated plywoods.
Copper Accumulation in the Digestive Caecae of Limnoria quadripunctata Holthius (Isopoda: Crustacea) Tunnelling CCA-Treated Wood in Laboratory Cultures
Authors: Tupper C. , Pitman A.J. , Cragg S. M. 
Published: October 2004

Summary
To investigate the mechanisms by which the isopod Limnoria tolerates copper, chromium and arsenic
when tunnelling CCA-treated wood in the marine environment, digestive caecae of specimens of L.
quadripunctata from CCA-treated and untreated Pinus sylvestris sapwood were examined using transmission
electron microscopy (TEM) and energy dispersive X-ray detection (EDX). Copper-containing
granules were found to be present in the small cells of the digestive caecae (midgut) of Limnoria from
both treated and untreated wood. However, individuals tunnelling treated timber contained a greater
number of granules, with six types of morphology being distinguished of which only two were present
in Limnoria from untreated wood. The presence of copper-containing granules in Limnoria from untreated
timber may be explained by the ability of this isopod to acquire and store copper from seawater for
use in enzymes and blood pigments. The increased number of copper granules in individuals tunnelling
treated wood was believed to result from elevated levels of this element in the food substrate. This ability
to store copper allows these organisms to tolerate this metal in the wood substrate and may explain
how this organism is able to attack CCA-treated wood in service. No chromium, or arsenic, was detected
in the digestive caecal cells.
Medium Density Fibreboard Manufactured from Blends of White Cypress Pine and Non-Durable Wood Species Shows Increased Resistance to Attack by the Subterranean Termite C. lacteus
Authors: Evans P.D. , Dimitriades S. , Cunningham R.B. , Donnelly C.F. 
Published: October 2004

Summary
Medium density fibreboards consisting of blends of the naturally durable wood species white cypress
pine (Callitris glaucophylla) and non-durable wood species were manufactured in a commercial plant
and subjected to a bioassay using the subterranean termite species, Coptotermes lacteus. A board composed
of 30% cypress pine, 30% slash pine (Pinus elliottii) and 40% of the naturally durable hardwood
species spotted gum (Corymbia maculata) was also manufactured and bioassayed against C. lacteus. The
aims were to determine (i) whether boards containing cypress pine possessed increased resistance to termite
attack compared to a control manufactured entirely from non-durable wood species; (ii) the relationship
between the cypress pine content of boards and their resistance (if any) to termite attack; (iii)
whether the termite resistance of boards containing cypress pine could be further enhanced by the addition
of spotted gum fibre. There was an inverse relationship between the cypress pine content of MDF
specimens and mass losses of the specimens during the bioassay; the percentage mass losses of specimens
containing 11.4, 16.2 and 34.2% cypress pine being 20.3, 13.4 and 8.8%, respectively, compared
to 32.8% for the control, which consisted of non-durable slash pine (80%) and hoop pine (Araucaria
cunninghamii) (20%) fibre. There was strong evidence that the inverse relationship between the cypress
pine content of boards and mass losses during the bioassay was linear, although a statistically significant
quadratic (curvilinear) effect was also apparent. The addition of spotted gum fibre to boards did not
increase their resistance to termite attack. Cypress pine heartwood contains a variety of extractives that
are either toxic or repellent to termites, and the increased termite resistance of MDF containing cypress
pine compared to the control is probably due to the insecticidal effect of such chemicals on C. lacteus.
The incorporation of cypress pine fibre into MDF shows promise as an alternative to chemical biocides
for increasing the resistance of MDF to termites. However, the response of termites to heartwood extractives
varies between species, and therefore further experimentation is needed to test the resistance of
MDF containing cypress pine fibre to attack by greater range of wood destroying termites under test conditions
that more closely simulate field conditions.
Bleachability of Alkaline Pulps. Part 1. The Importance of β-Aryl Ether Linkages in Lignin
Authors: Gellerstedt G. , Al-Dajani W. Wafa 
Published: October 2004

Summary
Analytical and structural studies were done on different types of alkaline pulps and their isolated residual
lignins. Although having the same degree of delignification after cooking, some pulps were easier to
bleach than others. All isolated residual lignins were found to contain β-aryl ether (β-O-4) structures in
reasonable amounts when analysed by thioacidolysis (≥10 % of the native lignin value). At decreasing
kappa numbers, there was also a corresponding decrease in the amount of β-aryl ether structures in the
residual lignin. Moreover, a high β-aryl ether content in the unbleached residual lignin after cooking was
found to contribute to a better bleachability of the pulp, especially when hydrogen peroxide stages were
involved. At the same degree of delignification, the superior bleachability of alkaline sulfite pulps over
kraft pulps was shown to be attributable to a higher content of β-aryl ether linkages in the former type
of pulps.
Pulping of Whole Jute Plant (Corchorus capsularies) by Soda-Amine Liquor
Authors: Jahan M. Sarwar , Farouqui F.I. 
Published: October 2004

Summary
Pulping of whole jute plant is done by sodium hydroxide and ethylenediamine (EDA) or monoethanolamine
(MEA) within 1 hour of cooking. The pulp yield is considerably higher than for the control
soda and kraft pulps. Pulps obtained are better in physical properties as compared to kraft and soda pulps.
The apparent density of soda-EDA pulps decreases with the increase of EDA in the soda liquor whereas
the apparent density of soda-MEA pulps increases with the increase of MEA in soda liquor.
Pattern of Alkali Impregnation of Poplar Wood at Moderate Conditions
Authors: Zanuttini M. , Citroni M. , Marzocchi V. 
Published: October 2004

Summary
The impregnation pattern of alkali in fresh Cottonwood is analysed. Isothermal process, medium alkali-concentration,
temperature below 100°C and tangential direction are considered. The degree of deacetylation
in the wood is taken as an indicator of the whole chemical action of the alkali. Profiles of alkali
concentration, alkali content, liquid content and acetyl content in the wood are experimentally determined.
The results show that wood behaves rather like a glassy polymeric solid placed in contact with a
solvent. An advancing boundary zone is established which separates an intact inner part from the outer
swollen zone. Alkali concentration and acetyl groups content profiles can approximately be described by
a model used to analyse the reaction of solids: the shrinking core model. The chemical reaction in the
front is the controlling mechanism. The swelling of the cell walls together with the occupation of the
hollow cavities of the wood by the liquor make it possible for the wood liquid content to increase up to
almost 3 g liquid g wood−1.
The procedure here adopted and the impregnation pattern proposed are valuable tools to analyse the
effect of wood direction and process variables such as temperature, alkali concentration and initial wood
moisture. They could also be very useful to build a model for alkaline impregnation of wood under moderate
conditions.
Variations in Transverse Fibre Wall Properties: Relations Between Elastic Properties and Structure
Authors: Bergander A. , Salmén L. 
Published: October 2004

Summary
The transverse mechanical properties of the wood fibre play important roles in the use of wood and its
fibres in various applications. However, the variation in properties of fibres from different parts of the
tree and the relation of these properties to the structure of the fibre is not yet established. This study
focuses on the variation in the transverse elastic modulus of the fibre wall and its relation to the fibril
structure of the S2- and S1-layer. For this reason the local fibril angle of radial and tangential fibre walls
were measured by polarisation confocal microscopy. It was shown that the variation in fibril angle of the
S2-layer seems to have very little influence on the transverse modulus of the fibres. Instead the thickness
and fibril angle of the S1- and thus also the S3-layer should contribute to the variation in transverse modulus
between earlywood and transition wood fibres. The importance of the ray cells for the transverse
elastic properties of the wood was also emphasised.
The effects of protective helmet use on physiology and cognition in young cricketers
Authors: Neave Nick , Emmett John , Moss Mark , Ayton Rebecca , Scholey Andrew , Wesnes Keith 
Published: October 2004

AbstractMany studies have reported physiological and cognitive decrements following heat stress. Of particular concern in cricket are the possible negative effects of sustained protective helmet use, as this leads to an increase in heat‐related stress. Correct and rapid decision making, and focused attention are essential for efficient performance whilst batting, and it is possible that helmet usage could impair such processes. In a repeated‐measures, randomized crossover study, physiological, self‐report, and cognitive measures were taken from 16 teenage cricketers before and after moderately intense (batting) exercise. Participants underwent the assessments twice, once while wearing a standard protective helmet, and again, when not wearing a helmet (counterbalanced). While helmet use did not lead to significant physiological changes, wearing a helmet led to some cognitive impairments in attention, vigilance and reaction times. These preliminary findings could have significance for cognitively demanding sports (and perhaps military and industrial settings) in which participants perform cognitively demanding operations under conditions of physical exercise whilst wearing protective helmets. Additional factors of hydration, exercise duration, and helmet design are discussed. Copyright © 2004 John Wiley & Sons, Ltd.