bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fibre Length and Microfibril Angle in Silver Birch (Betula pendula Roth)
Authors: Bonham V. A. , Barnett J. R. 
Published: October 2004

Summary
A comparative study was carried out on fibre length and microfibril angle in Betula pendula Roth. Fibre length increased and microfibril angle decreased from pith to bark. Microfibril angle remained constant from the 15th annual ring from the pith, to the outermost ring. Fibre length also reached a maximum length at this point although there were some differences at the 30th ring from the pith.
The Further Chemistry of Ellagic Acid: I. Synthesis of Tetramethylellagic Acid and Associated Polymer Precursors
Authors: Reitze J.D. , Przewloka S.R. , Shearer B.J. 
Published: October 2004

Summary
A quantitative method for the production of 3,3′,4,4′-tetra-O-methylellagic acid was developed. Ellagic acid was fully methylated under nitrogen and in air using dimethyl sulphate and 25% guanidinium methoxide in N-methyl-2-pyrrolidone. The synthesis of a range of polymer precursors derived from 3,3′,4,4′-tetra-O-methylellagic acid are outlined, including the previously unreported 2,3,4,2′,3′,4′-hexamethoxy-6,6′-diphenoyl-dichloride, 2,3,4,2′,3′,4′-hexamethoxy-6,6′-diisocyanato-diphenyl, 2,3,4, 2′,3′,4′-hexamethoxy-6,6′-diamino-diphenyl, 2,3,4,2′,3′,4′-hexamethoxy-6,6′-dihydroxymethyl-diphenyl and 2,3,4,2′,3′,4′-hexamethoxy-diphenyl-6,6′-dialdehyde.
Relationships between Density, Shrinkage, Extractives Content and Microfibril Angle in Tension Wood from Three Provenances of 10-Year-Old Eucalyptus globulus Labill
Authors: Washusen R. , Ades P. , Evans R. , Ilic J. , Vinden P. 
Published: October 2004

Summary
Density and microfibril angle (MFA) of tension wood and normal wood were assessed in the sapwood and heartwood, from three provenanaces of 10-year-old Eucalyptus globulus Labill. Density was measured using a modified saturation method that also enabled the calculation of the extractives lost during saturation. Microdensity and MFA were determined by SilviScan 2, a rapid X-ray densitometry and X-ray diffraction system developed at CSIRO. Significant differences were found in density and extractives between provenances and also density between the sapwood and adjacent heartwood from each provenance. This result may explain some of the drying differences between provenances found in an earlier study (Washusen and Ilic 2000). Sapwood samples with high percentages of tension wood fibres had high density and a significant positive correlation was found between microdensity and tension wood fibre percentage. MFA was found to be very low in normal wood in the sapwood, where most tension wood was found, so tension wood could not be identified by MFA. The positive association between tension wood and wood density suggests that caution should be taken when selecting trees for high wood density in tree improvement programs.
Characterization of Residual Lignins from Chemical Pulps of Spruce (Picea abies L.) and Beech (Fagus sylvatica L.) by Analytical Pyrolysis–Gas Chromatography/Mass Spectrometry
Authors: Choi J.-W. , Faix O. , Meier D. 
Published: October 2004

Summary
Residual lignins have been isolated by enzymatic hydrolysis from sulfite, kraft, ASAM and soda/AQ/MeOH pulps obtained both of spruce and beech wood. The protein content of the samples were in the range of 2 to 61 % and the carbohydrate content fluctuated roughly between 1 and 12 %. Seven of the isolates have been submitted to analytical pyrolysis (Py-GC/MS) aiming at the determination of the lignin composition in terms of 4-hydroxy-phenylpropane, guaiacylpropane, and syringylpropane units, referred to in the following as H, G, and S units. Pyrolysis of proteins leads mainly to phenol, cresol, and indole. Phenol and cresol of protein origin may influence seriously the H content determination of lignins. However, the contribution of protein to this compounds can be corrected successfully based on the intensity of the indole peak in the pyrograms. Nevertheless, the pyrolysis results should not be over-interpreted concerning the H contents in the case of samples heavily contaminated with proteins. As analytical pyrolysis overestimates the S content in a similar manner as the chemical degradation techniques do, an empirical correction equation was used to approximate the “true”" S content. Py-GC/MS gave systematic and reproducible differences between the residual lignins on the one hand, and the MWLs, which have been pyrolysed for comparison, on the other hand. The fingerprinting ability of analytical pyrolysis, the G/S ratios of beech residual lignins, and the unusual properties of ASAM residual lignins with their high S contents are discussed.
Effects of Acetylation and Hydrothermal Treatment on Lignin as Revealed by Cellular UV-Spectroscopy in Norway Spruce (Picea abies [L.] Karst.)
Authors: Sander C. , Koch G. 
Published: October 2004

Summary
The effect of two different wood modification treatments on the lignin of Norway spruce wood was studied by means of cellular UV-spectroscopy. The modification treatments chosen were acetylation using acetic anhydride and a two step hydrothermal treatment. Small cross sectional thin slides from the wood surface were taken and were subsequently analysed using a UV-micro-spectro-photometer. The modified samples were compared with a non-treated control sample. The results revealed changes in the absorption spectra of lignin after both modification treatments. Spectra of the compound middle lamella (CML) of acetylated wood revealed a decrease in the lignin-specific absorption maximum at 280nm, which is considered to be caused by superficial leaching of lignin due to acetylation. The retarding effect of acetylation on UV-degradation of wood is discussed. In hydrothermal-treated wood the 280nm maximum was increased within the S2 layer. This maximum remained almost unchanged in the CML while a lower maximum was observed at about 330nm. Changes in the chromophoric behaviour of lignin are probably caused by de-masking reactions within the S2 layer resulting from hydrolysis of carbohydrates and side chain reactions. Both treatments lead to a severe decrease in absorption at the lower end of the spectrum towards 250nm which is possibly attributed to changes or even splitting of biphenyls.
Furfural and Hydroxymethylfurfural as By-Products of FORMACELL Pulping
Authors: Lehnen Ralph , Saake Bodo , Nimz Horst H. 
Published: October 2004

Summary
The formation and stability of furans formed from pentoses and hexoses were studied in acetic acid/formic acid mixtures which are applied in the FORMACELL pulping process. For comparison, acetic acid/water mixtures with and without addition of HCl were included in the study. The investigations demonstrated that furfural can be obtained in high yields from xylose and xylan. Hexoses are converted to hydroxymethylfurfural (HMF), acetoxymethylfurfural (AMF) and furfural. Here, the water content of the reaction mixture influences the ratio of HMF and AMF in the solution. Stability studies revealed that furfural and HMF exhibit a high stability in acetic acid/formic acid mixtures. This explained the high furfural yields previously published for acetic acid pulping. The long-time stability of furans was investigated for 275 days at room temperature. No significant losses occurred suggesting that organic acids act as radical scavengers inhibiting oxidative degradation.
Chemical Structures of (+)-Catechin-Formaldehyde Reaction Products (Stiasny Precipitates) Under Strong Acid Conditions: Part 1. Solid-State 13C-NMR Analysis
Authors: Saito N. , Reilly M. , Yazaki Y. 
Published: October 2004

Summary
To determine more accurately the amount of polyflavanoids in tannin extracts from radiata pine bark, which react with formaldehyde, it is important to elucidate chemical structures of (﹢)-catechin-formaldehyde reaction products (Stiasny precipitates). The Stiasny value of 106.4% for (﹢)-catechin was obtained from the reaction with formaldehyde under strong acid conditions. This value is almost identical to the value calculated from the Stiasny precipitates, which were formed in the ratio of two molecules of (﹢)-catechin to three molecules of formaldehyde.
The solid-state 13C NMR spectrum was measured to elucidate the structures of the Stiasny precipitates, and analysed on the basis of the chemical shifts of (﹢)-catechin. The NMR results indicate that C-6 and C-8 in the A-ring are bonded by methylene bridges to form polymers, and also form methylene bridges with C2′, C5′ or C6′ in the B-ring of a catechin unit.
Consequently, the reaction products of (﹢)-catechin-formaldehyde under strong acid conditions (Stiasny precipitates) are (﹢)-catechin-polymers, which consist of two moles of (﹢)-catechin and three moles of formaldehyde. The methylene bridges are formed mostly between A-rings, and less frequently, between A- and B-rings and between B-rings of the catechin units.
Non-Wood Fiber as an Alternative to Wood Fiber in Chinas Pulp and Paper Industry
Authors: Hammett A. L. , Youngs Robert L. , Sun Xiufang , Chandra Mudit 
Published: October 2004

Summary
The pulp and paper industry in China has been growing rapidly as the nation's population and economy have grown. As a result, there has been a huge demand for pulp and paper raw materials. China has a long tradition for using non-wood raw materials for pulp and paper due to its limited forest resources and rich supply of agricultural residues and non-wood plants. Agricultural residues, such as rice straw and wheat straw, are traditional raw materials for China's paper industry. Massive plantation of bamboo provides an increasingly important source of raw material for pulp and paper. Problems with non-wood fiber include collection and transportation, storage and handling, washing, bleaching, papermaking, and chemical recovery. Small mills, primary users of non-wood fiber, are typically deficient in pollution control and subject to government closure. This paper reviews non-wood fibers commonly used in China's pulp and paper industry. By increased knowledge of use of non-wood fibers, wood suppliers can plan for access to the growing Chinese market.
Biological Control of Blue Stain in Pulpwood: Mechanisms of Control used by Phlebiopsis gigantea
Authors: Behrendt Chad J. , Blanchette Robert A. 
Published: October 2004

SummaryPhlebiopsis gigantea, a white-rot fungus currently being tested in biological processing applications for the pulp and paper industry, was shown to effectively inhibit blue stain fungi in both laboratory and field trials. Inoculation of logs withP. giganteashortly after cutting resulted in up to 86% colonization of logs in the laboratory and 100% in field studies. Colonization of logs by blue stain fungi such asOphiostoma piliferumandO. piceaewas greatly reduced or completely inhibited with prior inoculation byP. gigantea. In field studies, blue stain fungi colonized up to 53% of the sapwood and stained as much as 31% of the sapwood in non-inoculated control logs in contrast to 4% colonization and 2% stain in treated logs. Logs inoculated withO. piliferum2 weeks prior to inoculation withP. giganteawere 88% colonized byO. piliferumand had 33% of the sapwood stained after 7 weeks, and 33% colonized and 18% stained after 29 weeks. Scanning electron micrographs ofP. giganteaandO. piliferumhyphae showedP. giganteaparasitizing the blue stain fungus.Phlebiopsis giganteawas shown penetrating and growing adjacent to collapsed and disintegrated blue stain hyphae.Phlebiopsis giganteaalso decolorized sapwood previously stained blue.
Inhibition of the Photodiscoloration of Wood by Butyrylation
Authors: Chang Shang-Tzen , Chang Hui-Ting 
Published: October 2004

Summary
The lightfastness of butyrylated China fir (Cunninghamia lanceolata var. lanceolata) and maple (Acer
sp.) was evaluated in this study, and its effectiveness was compared with that of acetylated specimens.
The color fading in acetylated China fir and maple woods was reduced to half that of untreated specimens,
after a 24-day UV lightfastness test. The effectiveness of butyrylation on photodiscoloration prevention
in wood was even more pronounced than that with acetylation. With an 18.57% weight percent
gain, butyrylation remarkably inhibited the discoloration of wood following UV irradiation. Based on
infrared spectral analysis, the lignin of both untreated and butyrylated woods deteriorated after exposure
to UV light, but the holocellulose in butyrylated wood was more resistant to the UV light. Furthermore,
results obtained from diffuse reflectance UV-VIS spectral analysis elucidated that the absorption of irradiated
butyrylated wood, in comparison with that of the irradiated but untreated specimens, was lower
in both UV light and visible light regions. It also revealed that the inhibition of photodiscoloration of
wood by butyrylation was caused mainly by a significant reduction of chromophoric derivatives, such as
quinoid compounds, formed on the wood surface.
Lipophilic Extractives from Eucalyptus globulus Pulp during Kraft Cooking Followed by TCF and ECF Bleaching
Authors: Gutiérrez A. , Romero J. , Río J.C. del 
Published: October 2004

SummaryThe chemical composition of lipophilic extractives in paper pulps fromEucalyptus globuluswood during kraft cooking followed by TCF (“totally chlorine free”) and ECF (“elemental chlorine free”) bleaching sequences has been determined by gas chromatography and gas chromatography-mass spectrometry. The chemical analyses revealed that the composition of the lipophilic extractives in pulp after kraft cooking and TCF bleaching with hydrogen peroxide was similar to that ofE. globuluswood extractives, sitosterol and sitosterol esters being the predominant compounds. In contrast, the presence of these compounds was almost negligible in pulp after ECF bleaching with chlorine dioxide and only the saturated sterol stigmastanol, in both free and esterified forms, survived the bleaching.
Determination of Monosaccharide Composition of Eucalyptus globulus Wood by FTIR Spectroscopy
Authors: Rodrigues José , Puls Jürgen , Faix Oskar , Pereira Helena 
Published: October 2004

Summary
FTIR spectroscopy was used to estimate monosaccharide content in Eucalyptus globulus wood, using
the natural variability of the species for calibration and validation of the method . A total of 38 samples
from 9 year old trees from provenance trials was used. The composition ranged for glucose from 43.2%
to 59.5%, for xylose from 9.4% to 17.8%, for galactose from 0.5% to 5.4%, for mannose from 0% to
2.8%, and for rhamnose from 0.3% to 0.8%, based on extractive-free dry wood. The multivariate analysis
gave in general, better results with increased R2, lower SEC and SEP errors, although the univariate
method also gave good fits with high coefficient of determination (R2) based on remaining data once outliers
were removed. FTIR techniques may be used in large scale breeding programmes to measure wood
monosaccharide composition with considerably less effort and in shorter time than wet-lab methods,
once a reliable calibration has been made for the species.
Acetyl Group Distribution in Acetylated Wood Investigated by Microautoradiography
Authors: Rosenqvist Marie 
Published: October 2004

Summary
Sapwood of Scots pine (Pinus silvestris L.) was acetylated with 14C- and 3H-labelled acetic anhydride.
The distribution of acetyl groups was investigated with microautoradiography and microautoradiographs
were evaluated with ESEM, Environmental Scanning Electron Microscopy.
The investigation showed that the impregnation of wood with radioisotope-labelled substances provides
a good opportunity to investigate the location of substances covalently bonded to the wood material.
Introduced 14C-labelled acetyl groups show an even distribution in the wood cell wall, with no discernible
concentration gradients at acetylation levels of about 5, 15 and 20% weight gain. 3H-labelled
acetyl groups show an even distribution in the wood cell wall at 15 and 20% weight gain, with no discernible
concentration gradients. At the 5% weight gain level, however, an uneven distribution of 3H-labelled
acetyl groups over the cell wall is observed. Nevertheless, the unevenness is random and no concentration
gradient is discernible at this level.

3H with a relatively high resolution, 0.5–1 μm, compared to 14C with a resolution of 2–5 μm, gives
more accurate information about where exactly the acetyl groups are situated in the wood cell wall.
Acetic anhydride was evenly distributed when a full impregnation procedure was used. The chemical and
physical properties of acetic anhydride allow a uniform penetration into the pine cell wall and a complete
acetylation takes place when the specimens are heated.
Solid State NMR Analysis of β-13C-Enriched Lignocellulosic Material During Light-Induced Yellowing
Authors: Parkås Jim , Paulsson Magnus , Westermark Ulla , Terashima Noritsugu 
Published: October 2004

SummaryPhotoyellowing of lignocellulosic materials has been studied with a new technique based on solid state13C-NMR analysis of13C-enriched DHP in cell wall tissue. The selectively13C-enriched cell wall-dehydrogenation polymer (CW-DHP) was prepared directly on differentiating xylem from spruce (Picea abies) at pH 6.0 by administering β-13C-enriched coniferin in an enzymatic system consisting of glucose oxidase, β-glucosidase, and the naturally occurring water-insoluble enzymes remaining in the cell wall. The bonding pattern of the formed CW-DHP was found to be: 42% β-β, β-5, and β-1 substructures; 36% β-O-4 derived substructures; and 22% coniferyl alcohol and coniferaldehyde end-groups. The13C-NMR analysis of unirradiated and irradiated tissue revealed a decrease in the relative amount of coniferaldehyde and/or coniferyl alcohol end-groups during irradiation. Prolonged irradiation also introduced new signals centered at 37, 70, and 102 ppm. The results indicate that the present technique, with the formation of DHP in a naturally lignifying carbohydrate environment, has the potential of being a valuable tool for the study of structural changes of lignin during light-induced yellowing.
Reactions of the β-Aryl Ether Lignin Model 1-(4-Hydroxy-3-Methoxyphenyl)-2-(2-Methoxyphenoxy)-1-Propanol on Heating in Aqueous Solution
Authors: Li S. , Lundquist K. 
Published: October 2004

Summary
The reactions of the β-aryl ether lignin model 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1-propanol on heating in aqueous solution have been studied. Guaiacol, isoeugenol, vanillin, 1-(4-hydroxy-3-methoxyphenyl)-1-ethanol, 1,2-bis(4-hydroxy-3-methoxyphenyl)-1-propanol, 2-(4-hydroxy-3-methoxyphenyl)-7-methoxy-3-methyl-2,3-dihydrobenzo[b]furan, dehydrodiisoeugenol and trans-1,2-dihydrodehydroguaiaretic acid were detected in the reaction mixtures. The formation of the products can
be envisioned to proceed via homolysis of an intermediate quinone methide. When 2,6-dimethoxyphenol
was present in the reaction mixtures large amounts of 1-(4-hydroxy-3,5-dimethoxyphenyl)-2-(4-hydroxy-3-methoxyphenyl)-1-propanol were formed and the yields of guaiacol and isoeugenol were
comparatively high. The reaction product pattern can be explained by the occurrence of radical-exchange
reactions. The presence of wood meal in the reaction mixtures resulted in an increase in the yield of
isoeugenol and a lowering of the yield of dehydrodiisoeugenol. The changes in yields in this case can
also be explained by radical-exchange reactions. The significance of homolytic cleavage of β-aryl ether
linkages in connection with the technical processing of wood is discussed.
Structural Analysis of Residual and Technical Lignins by 1H-13C Correlation 2D NMR-Spectroscopy
Authors: Capanema Ewellyn A. , Balakshin Mikhail Yu , Chen Chen-Loung , Gratzl Josef S. , Gracz Hanna 
Published: October 2004

Summary
Structural analysis was conducted on residual lignin from pine Kraft AQ pulp, Eucalyptus Kraft lignin
from Eucalyptus globulus and Repap Organosolv lignin by 2D 13C-1H correlation NMR spectroscopic
techniques such as HMQC sequence. These lignins contain a rather wide variety of saturated aliphatic
groups. The HMQC NMR spectra of the lignins do not verify the presence of diarylmethane moieties in
any lignin investigated. The type and amount of other condensed structures depend on the nature of lignin
preparation. All the lignins investigated still contained β-O-4′, pino- and syringayresinol (β-β′) and
phenylcoumarane (β-5′) structures. Stilbene structures were also identified. Vinyl ether structures were
present only in Eucalyptus Kraft lignin. All the lignins contain α-carbonyl groups conjugated to aromatic
moieties as terminal side chains rather than involving β-O-4′ structures. No coniferyl alcohol and
coniferyl aldehyde type structures are detected in the lignins after pulping. The spectra of kraft lignins
show some new signals, the origin of which is discussed.
Experimental Determination of Stiffness Variation Across Growth Rings in Picea abies
Authors: Jernkvist L.O. , Thuvander F. 
Published: October 2004

Summary
The radial and tangential deformations in a single growth ring of Norway spruce, which was subjected
to moderate tensile loading in its radial direction, were measured by use of digital speckle photography.
From the measured displacement field, the transverse coefficients of elasticity ER
, ET
, GRT
and νTR were
determined with respect to radial position in the growth ring. As a result of the abrupt change in stiffness
from latewood to earlywood in the growth ring, it was possible to establish all four coefficients solely
from the radial tension test. The elastic modulus ET
was found to be a factor 15 larger in latewood
than in earlywood, whereas the corresponding variation for ER
was merely a factor 3. The measured variations
were in reasonable agreement with predictions from simple two-dimensional honeycomb models
of the growth ring cellular structure.
The average elastic moduli of the growth ring were found to be twice as large as ER
and ET
measured
in conventional tests on macroscale specimens, whereas the reverse was true for the shear modulus. An
explanation to these differences is sought by analysing the loading conditions and deformation behaviour
of macroscale specimens used in transverse stiffness testing of wood.
Determination of the Material Property Variations Across the Growth Ring of Softwood for Use in a Heterogeneous Drying Model Part 1. Capillary Pressure,Tracheid Model and Absolute Permeability
Authors: Perré Patrick , Turner Ian 
Published: October 2004

Summary
In this work, the extensive knowledge of wood gained at the Ecole Nationale du Génie Rural des Eaux
et Forêts by using a combination of microscopic observation and experimental work is being used to postulate
material property correlations for a macroscopic heterogeneous “Cerne” growth ring model of softwood.
Mathematical tools such as image analysis and homogenisation are used to develop models that
capture the effect of the density variation within the wood sample of important macroscopic physical
parameters. This first part is devoted to mass transfer in wood due to Darcy's law. Capillary pressure correlations
as a function of local density are deduced from image analysis. Thereafter, a tracheid model is
proposed for softwood. Its shape evolves from earlywood to latewood according to anatomical observations.
Liquid and gaseous permeability values are calculated from this model according to Poiseuille's
flow within cells and assuming a linear flow-pressure loss relationship through the pits.