bluuebunny/crossref_metadata_2025_split huggingface dataset:
Delignification mechanism during high-boiling solvent pulping. Part 6: Changes in lignin structure analyzed by 1H-13C correlation 2-D NMR spectroscopy
Authors: Kishimoto T. , Ueki A. , Takamori H. , Uraki Y. , Ubukata M. 
Published: September 2004

Abstract
In order to investigate the delignification mechanism during
high-boiling solvent (HBS) pulping, softwood HBS lignin
samples from todo fir (Abies sachalinensis) were
analyzed by 1H–13C correlation NMR spectroscopy
(HMQC). Nine lignin model compounds that may represent
the substructures in HBS lignin were prepared. The
1H and 13C NMR spectral data were compared with HBS
lignin samples. The HMQC spectra of HBS lignin samples
showed the disappearance of β-O-4 structures.
Introduction of a pulping solvent into lignin was plainly
observed with new signals in aliphatic regions. Only the
erythro β-1 structure was detected in softwood milled
wood lignin from todo fir by HMQC spectra. The β-1
structure was very reactive and probably produced the
stilbene structure. The β-β and β-5 structures remained
in HBS lignin. The 4-O-5 structure was successfully
detected by HMQC spectra, and it was found to be stable
under the conditions used.
Ozonation of conventional kraft and SuperBatch residual lignins in methanol/water and water
Authors: Widsten P. , Hortling B. , Poppius-Levlin K. 
Published: September 2004

Abstract
The chemistry of ozone bleaching of chemical pulps was
explored by ozonating residual lignins isolated from conventional
kraft and SuperBatch pulps in methanol/water
medium to detect possible differences in the reactivity of
the two types of lignin. SuperBatch lignin was ozonated
also in water to study the effect of ozonation medium on
the lignin reactivity. The residual lignins were found to
display similar reactivities in methanol/water, implying
that ozonation should result in equal delignification rates
for both conventional kraft and SuperBatch pulps unless
the rates of reagent diffusion in the pulps are different.
The lignins were partly oxidized to volatile and nonvolatile
low-molecular weight oxidation products by the so-called
“peeling mechanism”, according to which oxidation
products go into solution and insoluble reaction products
resemble the starting lignins. The reaction products
obtained upon ozonation of SuperBatch lignin in neutral
water resembled those formed in methanol/water, but
their yield was much lower. This is probably due to the
better solubility of lignin in methanol/water than in water
and/or higher degradability of lignin by ozone than by
radicals formed as ozone decomposition products.
Relationship between dissolution of fiber materials and development of pulp strength in alkaline peroxide bleaching of mechanical pulp
Authors: Pan G.X. 
Published: September 2004

Abstract
This study elucidates the relationship between the dissolution
of pulp components and the development of
fiber bonding properties in alkaline peroxide bleaching of
aspen mechanical pulp. In general, bleaching reactions
cause the removal of pulp substances from the fibers,
which in turn improves pulp strength properties. Nonetheless,
alkaline hydrolysis is particularly important to the
development of strength because this reaction mechanism
plays a key role in imparting additional carboxylic
acid groups onto the fibers. The strong correlation
between fiber carboxylic acid group concentration and
the amount of anionic dissolved substances makes it
possible for us to predict the strength properties of
bleached pulps by estimating the anionicity of bleaching
filtrates using analytical methods such as cationic
demand. The paper also provides insights into the importance
of the alkalinity in peroxide bleaching to the dissolution
of pulp materials and the strength development.
Nondestructive estimation of tracheid length from sections of radial wood strips by near infrared spectroscopy
Authors: Schimleck L.R. , Jones P.D. , Peter G.F. , Daniels R.F. , ClarkIII A. 
Published: September 2004

Abstract
The use of calibrated near infrared (NIR) spectroscopy for
predicting tracheid length of Pinus taeda L. (loblolly pine)
wood samples is described. Ten-mm sections of 14 P. taeda radial strips were selected and NIR spectra
obtained from the radial longitudinal face of each section.
The fibers in these sections were characterized in terms
of arithmetic and length-weighted mean tracheid length
using a fiber quality analyzer, and calibrations with NIR
spectra were developed for both measures of tracheid
length. Relationships were good, with coefficients of
determination (R
2) of 0.88 for arithmetic tracheid length
and 0.96 for length-weighted tracheid length. The accuracy
of NIR predicted length-weighted tracheid length
was sufficient for ranking purposes.
Heat transfer model for estimating pinene emissions from hot-pressing softwood flakeboard
Authors: Radhakrishnan J.S. , Banerjee S. 
Published: September 2004

Abstract
A heat transfer model for estimating pinene emissions
from hot-pressing strand for the manufacture of flake-board
has been constructed from first principles and validated.
The model predicts α-pinene emissions of 0.4 kg/1000 kg from a 0.95-cm board, which is within the
0.3–0.6 kg/1000 kg range reported for commercial operations.
Most of the emissions originate from the hot
1-mm layer of wood adjoining the platen surface. As a
result, residual pinene in the board is depleted at the surface
for both commercial and laboratory-prepared
boards. Emissions are drastically reduced when the mat
is surfaced with a layer of aspen, which prevents the hot
platen from directly contacting softwood.
Monitoring creep-rupture in oriented strandboard using acoustic emission: Effects of moisture content
Authors: Vun R.Y. , Beall F.C. 
Published: September 2004

Abstract
Creep-rupture studies of large specimens of commercial
oriented strandboard (OSB) were conducted using a fourpoint
flexural test in combination with an acoustic emission
(AE) monitoring system. Four equilibrium moisture
content (EMC) conditioning and testing regimens were
used: ambient room conditions, constantly moderate
EMC (12/12), dynamic rising EMC (12/24), and constant
high EMC (24/24). Compared with deflection, the cumulative
event AE parameter was found to be more sensitive
and representative to detect cumulative damage to final
failure. Under 80% ultimate stress, the 24/24 specimens
had the highest creep rate (1.43 mm h−1) as compared
with 0.27 and 0.04 mm h−1 for 12/24 and 12/12 specimens,
respectively. However, for the 12/24 specimens, a
step-like deflection occurred, accelerating the rupture
process and attaining the greatest creep factor of 2.28—a recommended safety factor for prolonged exposure to
humid service conditions. The total recovered deflection
under ambient conditions was 85% recoverable elastic,
5% recoverable viscoelastic, and 10% permanent irreversible
creep. Correspondingly, the total recovered stiffness
was 70% recoverable elastic, 10% recoverable
viscoelastic, and 20% permanent irreversible creep. The
observed creep-rupture limit of the OSB was 24 days to
failure.
Adhesives made from isocyanates and pyrolysis oils for wood composites
Authors: Gagnon M. , Roy C. , Riedl B. 
Published: September 2004

Abstract
Wood adhesives derived from softwood bark pyrolysis
oils (PO) and isocyanates (pMDI) have been developed
for particleboards with a non-conventional blending system.
The PO produced by the vacuum pyrolysis Pyrocycling™ process was used to replace between 30 and
40% by weight of the pMDI in a 4% adhesive-containing
particleboard. Results showed that mechanical properties
(IB, MOE and MOR) and thickness swelling of homogeneous
boards exceeded the minimum requirements
set by ANSI A208.1-1993 and ASTM 1037-96a standards.
The study showed that pyrolysis oils can be mixed
at ratios as high as 40% with pMDI and give acceptable
interior grade particleboard properties. It was also shown
that PO reduces panel to metal adhesion by 86%, in
comparison to the control.
Effect of wood acidity and catalyst on UF resin gel time
Authors: Xing C. , Zhang S.Y. , Deng J. 
Published: September 2004

Abstract
Knowledge of pH and buffering capacity of raw fiber
materials is important for understanding the effects of
raw material on the curing rate of urea formaldehyde (UF)
resin, used for panel manufacturing, especially with some
less-desirable wood materials such as bark, top, and
commercial thinnings.
The effects of pH and buffering capacity as well as
catalyst content on the gel time of UF resin were investigated.
The results obtained from this study indicate that
bark has a lower pH value as well as higher acid and
alkaline buffering capacities than wood of the same species
due to their extractives. The pH values of the raw
fiber materials studied decrease with increased absolute
and relative acid buffering capacity due to the increased
absolute acidity mass in the solution.
At lower levels of added catalyst, the effect of raw
material pH on UF resin gel time is significant, while it is
insignificant at higher catalyst contents. This may be due
to the acidity of wood, which is the main acid catalyst
source of the mixture at lower levels of added catalyst,
while at higher levels, catalyst is the main source. With
higher catalyst contents, all studied raw materials mixed
with UF resin result in a longer gel time than does UF
resin alone.
Exploratory evaluation of oscillation drying for thick hemlock timbers
Authors: Sackey E. K. , Avramidis S. , Oliveira L.C. 
Published: September 2004

Abstract
The study explores the effect of dry-bulb (Tdb
) and wet-bulb
(Twb
) temperature oscillation in a conventional kiln
on the drying characteristics of 105-mm-square Pacific
coast hemlock. Five kiln-charges were dried using four
oscillating drying schedules and a control. The base drying
temperatures for the control were Twb
=53°C,
Tdb
=60°C for the first drying phase and increased to
Twb
=65°C, Tdb
=80°C in the second phase. These temperatures
were oscillated at two amplitude and frequency
combinations, namely, 3°C for 4 h (low) and 6°C for 8 h
(high). The results indicated that the total impact of oscillating
schedules on the drying rate was more pronounced
at the early stages of the drying process.
Oscillating Tdb
at higher amplitudes increased drying rate
by 12%, whereas the low amplitude counterpart reduced
kiln residence time by 10–14%. The final moisture content
variability decreased in both Twb
oscillated schedules.
Core and shell moisture content variation also
slightly decreased in the low amplitude Twb
oscillated
schedules. High amplitude oscillated Tdb
also showed
5% less casehardening than the control, whilst its low
amplitude counterpart increased. The low amplitude Twb

oscillated schedule had the least surface checks and
splits.
A biopulping mechanism: Creation of acid groups on fiber
Authors: Hunt C. , Kenealy W. , Horn E. , Houtman C. 
Published: September 2004

Abstract
We investigated how biopulping modifies chemical and
physical properties of wood and how these changes
affect the properties of the resulting fiber. Mechanical and
chemical testing revealed wood cell changes during
2 weeks of colonization by Ceriporiopsis subvermispora.
Typical mechanical properties, such as modulus of elasticity
and maximum load, tracked reductions in energy
needed for mechanical refining to pulp. The data indicate
the fiber saturation point of spruce increased from 29%
to 42% during biopulping. At the same time, titratable
acid groups increased up to 62%. Chemical analysis
showed that oxalic acid esters were produced in the
wood during biopulping in sufficient amounts to account
for the increase in acid groups. The benefits of biopulping—energy savings and increased handsheet strength—as
well as other physical property changes are consistent
with the mechanism we propose: biopulping increases
the acid group content of wood.
Enzymatically polymerized phenolic compounds as wood preservatives
Authors: Rättö M. , Ritschkoff A.-C. , Viikari L. 
Published: September 2004

Abstract
Phenolic compounds were studied as natural preservatives
against wood decaying fungi. Vanillin and tannin
decreased the growth of the test organisms Coniophora puteana and Coriolus versicolor and decreased the
weight losses caused by these organisms in wood
blocks. Both compounds were, however, leached in standard
washing tests, and higher weight losses were
observed in leached samples. Enzymatic polymerization
with laccase was used as a means of binding the phenolic
preservatives into the wood. Using an optimized
laccase dosage, wood impregnation with enzymatically
polymerized vanillin reduced the weight loss by C. puteana from 25% to 5%.
The Probability and Chromosomal Extent of trans-specific Polymorphism
Authors: Wiuf Carsten , Zhao Keyan , Innan Hideki , Nordborg Magnus 
Published: September 2004

Abstract
Balancing selection may result in trans-specific polymorphism: the maintenance of allelic classes that transcend species boundaries by virtue of being more ancient than the species themselves. At the selected site, gene genealogies are expected not to reflect the species tree. Because of linkage, the same will be true for part of the surrounding chromosomal region. Here we obtain various approximations for the distribution of the length of this region and discuss the practical implications of our results. Our main finding is that the trans-specific region surrounding a single-locus balanced polymorphism is expected to be quite short, probably too short to be readily detectable. Thus lack of obvious trans-specific polymorphism should not be taken as evidence against balancing selection. When trans-specific polymorphism is obvious, on the other hand, it may be reasonable to argue that selection must be acting on multiple sites or that recombination is suppressed in the surrounding region.
Tree Scanning
Authors: Templeton Alan R , Maxwell Taylor , Posada David , Stengård Jari H , Boerwinkle Eric , Sing Charles F 
Published: September 2004

Abstract
We use evolutionary trees of haplotypes to study phenotypic associations by exhaustively examining all possible biallelic partitions of the tree, a technique we call tree scanning. If the first scan detects significant associations, additional rounds of tree scanning are used to partition the tree into three or more allelic classes. Two worked examples are presented. The first is a reanalysis of associations between haplotypes at the Alcohol Dehydrogenase locus in Drosophila melanogaster that was previously analyzed using a nested clade analysis, a more complicated technique for using haplotype trees to detect phenotypic associations. Tree scanning and the nested clade analysis yield the same inferences when permutation testing is used with both approaches. The second example is an analysis of associations between variation in various lipid traits and genetic variation at the Apolipoprotein E (APOE) gene in three human populations. Tree scanning successfully identified phenotypic associations expected from previous analyses. Tree scanning for the most part detected more associations and provided a better biological interpretative framework than single SNP analyses. We also show how prior information can be incorporated into the tree scan by starting with the traditional three electrophoretic alleles at APOE. Tree scanning detected genetically determined phenotypic heterogeneity within all three electrophoretic allelic classes. Overall, tree scanning is a simple, powerful, and flexible method for using haplotype trees to detect phenotype/genotype associations at candidate loci.
Reconstituting the Frequency Spectrum of Ascertained Single-Nucleotide Polymorphism Data
Authors: Nielsen Rasmus , Hubisz Melissa J , Clark Andrew G 
Published: September 2004

Abstract
Most of the available SNP data have eluded valid population genetic analysis because most population genetical methods do not correctly accommodate the special discovery process used to identify SNPs. Most of the available SNP data have allele frequency distributions that are biased by the ascertainment protocol. We here show how this problem can be corrected by obtaining maximum-likelihood estimates of the true allele frequency distribution. In simple cases, the ML estimate of the true allele frequency distribution can be obtained analytically, but in other cases computational methods based on numerical optimization or the EM algorithm must be used. We illustrate the new correction method by analyzing some previously published SNP data from the SNP Consortium. Appropriate treatment of SNP ascertainment is vital to our ability to make correct inferences from the data of the International HapMap Project.
Molecular Cytogenetic Characterization of the Antirrhinum majus GenomeSequence data from this article have been deposited with the EMBL/GenBank Data Libraries under the accession nos. AY630561 (for BAC 5E10) and AY6305612 (for BAC 36D21).
Authors: Zhang Dongfen , Yang Qiuying , Bao Weidong , Zhang Yu , Han Bin , Xue Yongbiao , Cheng Zhukuan 
Published: September 2004

Abstract
As a model system in classical plant genetics, the genus Antirrhinum has been well studied, especially in gametophytic self-incompatibility, flower development biology, and transposon-induced mutation. In contrast to the advances in genetic and molecular studies, little is known about Antirrhinum cytogenetics. In this study, we isolated two tandem repetitive sequences, CentA1 and CentA2, from the centromeric regions of Antirrhinum chromosomes. A standard karyotype has been established by anchoring these centromeric repeats on meiotic pachytene chromosome using FISH. An ideogram based on the DAPI-staining pattern of pachytene chromosomes was developed to depict the distribution of heterochromatin in the Antirrhinum majus genome. To integrate the genetic and chromosomal maps, we selected one or two molecular markers from each linkage group to screen an Antirrhinum transformation-competent artificial chromosome (TAC) library. These genetically anchored TAC clones were labeled as FISH probes to hybridize to pachytene chromosomes of A. majus. As a result, the relationship between chromosomes and the linkage groups (LGs) in Antirrhinum has been established.
Mapping Quantitative Trait Loci for Anxiety in Chromosome Substitution Strains of Mice
Authors: Singer Jonathan B , Hill Annie E , Nadeau Joseph H , Lander Eric S 
Published: September 2004

Abstract
Anxious behavior in the mouse is a complex quantitative phenotype that varies widely among inbred mouse strains. We examined a panel of chromosome substitution strains bearing individual A/J chromosomes in an otherwise C57BL/6J background in open-field and light-dark transition tests. Our results confirmed previous reports of quantitative trait loci (QTL) on chromosomes 1, 4, and 15 and identified novel loci on chromosomes 6 and 17. The studies were replicated in two separate laboratories. Systematic differences in the overall activity level were found between the two facilities, but the presence of the QTL was confirmed in both laboratories. We also identified specific effects on open-field defecation and center avoidance and distinguished them from overall open-field activity.
Quantifying the Relationship Between Gene Expressions and Trait Values in General Pedigrees
Authors: Lu Yan , Liu Peng-Yuan , Liu Yong-Jun , Xu Fu-Hua , Deng Hong-Wen 
Published: September 2004

Abstract
Treating mRNA transcript abundances as quantitative traits and examining their relationships with clinical traits have been pursued by using an analytical approach of quantitative genetics. Recently, Kraft et al. presented a family expression association test (FEXAT) for correlation between gene expressions and trait values with a family-based (sibships) design. This statistic did not account for biological relationships of related subjects, which may inflate type I error rate and/or decrease power of statistical tests. In this article, we propose two new test statistics based on a variance-components approach for analyses of microarray data obtained from general pedigrees. Our methods accommodate covariance between relatives for unmeasured genetic effects and directly model covariates of clinical importance. The efficacy and validity of our methods are investigated by using simulated data under different sample sizes, family sizes, and family structures. The proposed LR method has correct type I error rate with moderate to large sample sizes regardless of family structure and family sizes. It has higher power with complex pedigrees and similar power to the FEXAT with sibships. The other proposed FEXAT(R) method is favorable with large family sizes, regardless of sample sizes and family structure. Our methods, robust to population stratification, are complementary to the FEXAT in expression-trait association studies.
The Caenorhabditis elegans Ror RTK CAM-1 Inhibits EGL-20/Wnt Signaling in Cell Migration
Authors: Forrester Wayne C , Kim Changsung , Garriga Gian 
Published: September 2004

Abstract
During Caenorhabditis elegans development, the HSN neurons and the right Q neuroblast and its descendants undergo long-range anteriorly directed migrations. Both of these migrations require EGL-20, a C. elegans Wnt homolog. Through a canonical Wnt signaling pathway, EGL-20/Wnt transcriptionally activates the Hox gene mab-5 in the left Q neuroblast and its descendants, causing the cells to migrate posteriorly. In this report, we show that CAM-1, a Ror receptor tyrosine kinase (RTK) family member, inhibits EGL-20 signaling. Excess EGL-20, like loss of cam-1, caused the HSNs to migrate too far anteriorly. Excess CAM-1, like loss of egl-20, shifted the final positions of the HSNs posteriorly and caused the left Q neuroblast descendants to migrate anteriorly. The reversal in the migration of the left Q neuroblast and its descendants resulted from a failure to express mab-5, an egl-20 mutant phenotype. Our data suggest that CAM-1 negatively regulates EGL-20.
Non-Mendelian Inheritance Induced by Gene Amplification in the Germ Nucleus of Paramecium tetraurelia
Authors: Matsuda Atsushi , Takahashi Mihoko 
Published: September 2004

Abstract
A genetic investigation of strain d4-95, which carries a recessive mutant allele (pwB95) of pawn-B, one of the controlling elements of voltage-dependent calcium channels in Paramecium tetraurelia, revealed a non-Mendelian feature. Progeny of the cross between d4-95 and wild type often expressed a clonally stable mutant phenotype, even when they had a wild-type gene. The mutant phenotype was also expressed after self-fertilization of theoretical wild-type homozygotes recovered from the cross. Our molecular analysis demonstrated that the copy number of the mutant pwB gene in the micro- and macronucleus of d4-95 was much greater than that of the wild type. Most of the amplified, extra pwB gene copies in d4-95 were heritable independently from the original pwB locus. Repeated backcrossing of d4-95 with the wild type to dilute extra pwB genes in the strain produced segregants with a completely normal Mendelian trait in testcrosses. These results strongly suggest that a non-Mendelian inheritance of d4-95 was induced by gene amplification in the micronucleus.