bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alkaline Hydrolysis of Nonphenolic β-0-4 Lignin Models: Substituent Effect of the A-Ring on the Rate
Authors: Schultz T. P. , Fisher T. H. 
Published: September 2004

Summary
Six nonphenolic β-0-4 lignin models substituted on the phenyl A-ring [unsubstituted; 3,5-dimethoxyl; 3,4-dimethoxyl; 3-methoxyl; 4-methoxyl; and 4-methyl] were synthesized and the alkaline
hydrolysis rates at 170°C determined. Electron-withdrawing substituents enhanced the hydrolysis
rate, but this effect was relatively minor. Over 90% of the disappearance of the dimer
could be accounted for by appearance of the B-ring phenolic product for all compounds, which
suggests that minimal side reactions occurred.
Photosensitized Delignification of Residual Lignin and Chemical Pulp from Eucalyptus grandis Wood
Authors: Perez D. Da Silva , Castellan A. , Nourmamode A. , Grelier S. , Ruggiero R. , Machado A. E. H. 
Published: September 2004

Summary
Bleached pulps were obtained from a Eucalyptus grandis peroxyformic/formic acid chemical pulp
using oxygen, hydrogen peroxide, photosensitizers (methylene blue, Fe (II) 4,4′,4″,4‴-tetrasulfophthalocyanine,
hemin, hematoporphyrin) and/or TiO2. Residual lignin of unbleached pulp, isolated
and characterized by size exclusion chromatography, 31P NMR and thioacidolysis, was used to
study the photochemical reactions occurring during the bleaching process. The main reactions
were conversion of phenolic aromatic units into carboxylic acids and cleavage of the β-O-4 ether
bonds leading to a depolymerization of the lignin framework into smaller fragments.
New Method to Follow the Dimerisation Reaction Occuring during Oxidation of 4-Ethylguaiacol
Authors: Sippola V. , Viljava T.-R. , Vilonen K. , Krause O. 
Published: September 2004

Summary
4-Ethylguaiacol is a phenolic model compound used to study the oxidation of lignin. A new method
was developed to determine 4,4′-diethyl-6,6′-biguaiacol, an unwanted side-product, in the oxidation
of 4-ethylguaiacol. The sample is extracted with ethyl acetate to separate 4,4′-diethyl-6,6′-biguaiacol
from the water-soluble oxidation catalyst. No other treatment is required before analysis with a standard
UV-Vis spectrophotometer. The spectrophotometer is calibrated to measure concentrations of
4,4′-diethyl-6,6′-biguaiacol up to 0.3 mM. With the new method, the concentrations of 4,4′-diethyl-6,6′-biguaiacol can be reliably determined over a wide alkaline pH range. The performance of the
method was demonstrated in experiments investigating the formation of 4,4′-diethyl-6,6′-biguaiacol
in the autoxidation and cobalt-sulphosalen catalysed oxidation of 4-ethylguaiacol. In the conditions
of the studies (1 bar oxygen pressure and 50°C), a low (0.01 mM) concentration of Co-sulphosalen
clearly increased the total conversion of 4-ethylguaiacol. However, relative to autoxidation, the conversions
achieved in the presence of the catalyst were just as sensitive to pH, and the yields of the undesired
dimeric product, 4,4′-diethyl-6,6′-biguaiacol, were higher.
Surface Chemistry of Eucalyptus Wood Pulp Fibres: Effects of Chemical Pulping
Authors: Fardim P. , Durán N. 
Published: September 2004

Summary
The surface chemistry of Eucalyptus grandis wood pulp fibres was investigated using the sessile
drop apparent contact angle, XPS and TOF-SIMS techniques. Pulp fibres were studied using different
chemical pulping conditions. The pulping affected the surface coverage of lignin and extractives,
as indicated by XPS, and the work of adhesion with water, as estimated from contact angle
determinations. The amount of surface lignin decreased while surface extractives and work of adhesion
with water increased in relation to the amount of active alkali used in the pulping. Desorption
and analysis of surface extractives by TOF-SIMS showed sterols, fatty acid calcium and sodium
salts. After acetone extraction the spectra obtained by TOF-SIMS showed changes. However, calcium
and sodium salts of fatty acids were still detected, indicating their resistance to solvent extraction.
This resistance to extraction can affect the lignin and extractive surface coverage estimations
using XPS due to the contribution of the carbon content after extraction. The extent of
interference was, however, uncertain.
Delignification Mechanism during High-Boiling Solvent Pulping. Part 2. Homolysis of Guaiacylglycerol-β-Guaiacyl Ether
Authors: Kishimoto T. , Sano Y. 
Published: September 2004

Summary
A phenolic β-O-4 type lignin model compound, guaiacylglycerol-β-guaiacyl ether, was treated with
70 wt % aq 1,4-butanediol solution at 180°C to investigate the delignification mechanism under
high-boiling solvent (HBS) pulping conditions. Thirteen compounds including four monomers, six
dimers, two trimers and a tetramer were isolated from the reaction products. Most of these products
were generated by recombination of phenoxy radicals formed by homolysis of the β-aryl
ether. The results suggest that phenolic β-O-4 linkages in lignin are cleaved homolytically (radical
mechanism) via quinone methide intermediates under HBS pulping conditions.
Influence of Coating Additives on Water Vapour Absorption and Desorption in Norway Spruce
Authors: Ekstedt J. 
Published: September 2004

Summary
The growing concern for the environment and occupational health aspects have led to the development
and use of waterborne coatings for architectural applications. These coatings can be considered
as a two-phase system with the binder emulsified or dispersed in the water phase. During
film formation, phase separation occurs and coating additives can be mobilised and transported
into wood, thus changing wood moisture sorption characteristics. In the present study, wood samples
were treated with various coating additives, normally used in waterborne coatings, and exposed
to various humid conditions. The moisture adsorption and desorption in the treated wood
samples was compared to untreated wood samples. It is shown that the presence of substances
common in waterborne coatings changes the moisture sorption characteristics of wood. The presence
of a surfactant, nonylphenol ethoxyphenoxylate adduct, and the presence of a rheology modifier,
hydroxyethyl cellulose, lower the rate of moisture absorption and, to a great extent, delay the
release of moisture during desorption. Due to the fact that these substances occur in waterborne
coatings, may be mobilised during and after film formation and accumulate at the coating/substrate
interface, there is a great probability that these substances change the moisture sorption
characteristics of the wood substrate in an unfavourable way and create unexpected moisture conditions
at the coating/wood interface.
In situ Longitudinal Tensile Tests of Pine Wood in an Environmental Scanning Electron Microscope
Authors: Sippola M. , Frühmann K. 
Published: September 2004

Summary
To study wood fracture on its cellular level, small tensile specimens of pine (Pinus sylvestris [L.])
were fractured in situ in tension inside the chamber of an ESEM (Environmental Scanning Electron
Microscope). Fractured surfaces of macroscopic tensile test specimens were also studied with
an ESEM. The same kind of fracture phenomena were observed in both small and large specimens.
The in situ tests proved to be reproducible and the results revealed typical fracture propagation0
directions and order in softwood under longitudinal tension. The gradual change of material
properties of wood in the radial direction was found to strongly influence the fracture process.
The influence of personality and anxiety on the oral performance of Japanese speakers of English
Authors: Oya Taeko , Manalo Emmanuel , Greenwood Jackie 
Published: September 2004

AbstractThis study investigated the relationship between personality and anxiety characteristics of Japanese students and their oral performance in English. The participants were 73 native‐speakers of Japanese who were studying English at various language schools in New Zealand. They were administered the Maudsley Personality Inventory, the Spielberger State Anxiety Inventory, and a story‐retelling task which was scored in terms of oral fluency, accuracy, complexity, and global impression. Significant correlations were found between extraversion and global impression scores, and state anxiety and clause accuracy scores. These findings suggest that participants who were more extraverted produced better global impressions during their oral performance, and those who were experiencing higher levels of state anxiety made more errors in their spoken use of clauses. Copyright © 2004 John Wiley & Sons, Ltd.
Inorganic Nanotubes
Authors: Remškar M. 
Published: September 2004

AbstractSince the first report on the synthesis of inorganic WS2 nanotubes in 1992, the number of articles on the successful growth of different inorganic nanotubes has increased rapidly, emphasizing the importance of this field for nanotechnology. Although there are some geometrical similarities to carbon nanotubes, inorganic nanotubes are distinguished by important peculiarities, from their growth mechanisms to the physical and chemical properties that are attractive for potential applications. Their structural properties, which are important for such applications, are discussed in this review.
Essential thrombocythemia terminating in pure erythroleukemia
Authors: Kreft Andreas , Burg Jürgen , Fischer Thomas , Kirkpatrick Charles James 
Published: September 2004

AbstractTransformation into acute leukemia is a rare event in essential thrombocythemia (ET). The blasts are usually of myeloid, rarely of megakaryoblastic differentiation. We present the case of a patient with pure erythroleukemia after a nearly 10‐year course of ET, which was treated with hydroxyurea. The patient, a 58‐year‐old male, presented with an elevated thrombocyte count (926,000/μL) and normal values of hemoglobin and leukocytes. After 10 years of therapy with hydroxyurea, the patient developed acute leukemia of solely erythroid differentiation. Chemotherapy with cytarabine and daunorubicin resulted in incomplete remission. The patient died 2 months after diagnosis of acute erythroleukemia. Transformation of ET into erythroleukemia may demonstrate the pluripotent potential of the neoplastic hemopoietic stem cell, with the ability to cause acute leukemia not only of myeloid or megakaryoblastic but also of erythroid lineage. Am. J. Hematol. 77:140–143, 2004. © 2004 Wiley‐Liss, Inc.
Rituximab for treatment of refractory/relapsing thrombotic thrombocytopenic purpura (TTP)
Authors: Ahmad Afaq , Aggarwal Anita , Sharma Daya , Dave Harish P. , Kinsella Virginia , Rick Margaret E. , Schechter Geraldine P. 
Published: September 2004

AbstractPlasma exchange is the standard treatment for thrombotic thrombocytopenic purpura (TTP). For patients refractory to plasma exchange, treatment options are limited and often unsuccessful. The platelet thrombi that form in acquired TTP are believed to result from the presence of procoagulant ultralarge multimers of von Willebrand factor (VWF) in the circulation due to autoantibody inhibition of VWF cleaving protease (ADAMTS‐13), the enzyme that normally cleaves the ultralarge multimers. Rituximab, a chimeric monoclonal antibody against CD20, has been recognized as a useful therapy for antibody‐mediated autoimmune disease. We therefore treated four patients with recurrent TTP with 2 or 4 weekly doses of rituximab in addition to corticosteroids, vincristine, plasma, or continuing plasma exchange. Three patients responded with prompt improvement in microangiopathic hemolytic anemia and thrombocytopenia, which allowed plasma exchange to be discontinued or avoided and prednisone to be rapidly discontinued. Two of the 3 responders have remained in unmaintained complete remission for 13+ months. The third patient relapsed at 13 months; a second course of rituximab and prednisone resulted in an unmaintained remission for 6+ months. All four patients were tested for ADAMTS‐13 activity and its inhibitor at a point in their course when samples were available. Low ADAMTS‐13 activity was noted in 3 patients tested at relapse, and the inhibitor activity was detectable in 2 patients. ADAMTS‐13 activity increased during remission in one of these 2 patients although the patient had a persistence of the inhibitor. One patient tested only during remission had a normal ADAMTS‐13 level. We conclude that rituximab may have a role and deserves further study in the treatment of patients with relapsing TTP. Am. J. Hematol. 77:171–176, 2004. © 2004 Wiley‐Liss, Inc.
Genetic variants implicated in personality: A review of the more promising candidates
Authors: Savitz Jonathan B. , Ramesar Rajkumar S. 
Published: September 2004

AbstractAlleles of the serotonin transporter gene (SERT) and the dopamine 4 receptor gene (DRD4) were first associated with anxiety‐related and novelty‐seeking personality traits, respectively, in 1996. These early successes precipitated a flood of research into the genetic basis of personality; a quest that has yet to yield decisive answers. Here, both the theoretical and the empirical evidence implicating specific loci—in particular SERT and DRD4—in the development of personality is evaluated. Despite a paucity of statistically significant results following post‐hoc analysis, and an excess of positive results derived from studies with small sample sizes, the existence of a genuine effect is argued for: a gene‐personality relationship rendered periodically latent through genetic epistasis, gene–environment interactions, variation in genetic background, and the presence of other confounding variables. © 2004 Wiley‐Liss, Inc.
Phenotype studies of the DRD4 gene polymorphisms in ADHD: Association with oppositional defiant disorder and positive family history
Authors: Kirley Aiveen , Lowe Naomi , Mullins Celine , McCarron Mary , Daly Grainne , Waldman Irwin , Fitzgerald Michael , Gill Michael , Hawi Ziarih 
Published: September 2004

AbstractThe objective of this study was to investigate association of DRD4 polymorphisms with ADHD subtypes for which there is evidence for increased heritability. The genetic variants tested were the 120 bp insertion/deletion, the −616, −521, −376, and the 48 bp DRD4 VNTR. The primary analyses were of association with oppositional defiant disorder (ODD), conduct disorder (CD), and diagnostic subtypes. Secondary analyses of clinical subtype were exploratory in nature and included analysis of association of DRD4 polymorphisms with family history of ADHD. We observed significant association between DRD4 7‐repeat allele transmission and ADHD children with comorbid ODD (χ2 = 6.74, df = 1, P = 0.01, OR = 2.45) The DRD4 7‐repeat allele was also significantly associated with family history positive ADHD (χ2 = 10.12, df = 1, P = 0.0021, OR = 3.57). We observed no significant distortion in the transmission of any of the tested DRD4 variants with inattentive or hyperactive‐impulsive subtypes or symptom dimensions. In conclusion, our findings of increased DRD4 7‐repeat allele transmission in ODD extend those reported by Holmes et al. [2002: Am J Med Genet Neuropsychiatr 114:150–153]. To our knowledge, this is the first study to report association of the DRD4 7‐repeat allele with ADHD children who have a positive family history of ADHD. Overall, the results from this study support the investigation of clinical subtypes in molecular genetic studies of ADHD. © 2004 Wiley‐Liss, Inc.
Ketogenic treatment reduces deleted mitochondrial DNAs in cultured human cells
Authors: Santra Sumana , Gilkerson Robert W. , Davidson Mercy , Schon Eric A. 
Published: September 2004

AbstractImpairment of mitochondrial energy metabolism has been associated with a wide range of human disorders. Large‐scale partial deletions of mitochondrial DNA (mtDNA) cause sporadic Kearns–Sayre syndrome, a fatal multisystem disorder, in which the majority of mtDNAs in affected tissues have deletions (Δ‐mtDNAs). Since most mtDNA‐related diseases, including Kearns–Sayre syndrome, are recessive, only a few wild‐type mtDNAs can compensate for the deleterious effects of many Δ‐mtDNAs. We have developed a pharmacological approach to reduce the proportion of Δ‐mtDNAs in vitro, in which we grow cells in medium containing ketone bodies, replacing glucose as the carbon source. Cells containing 100% Δ‐mtDNA died after 5 days of treatment, whereas those containing 100% wild‐type mtDNA survived. Furthermore, in a cloned heteroplasmic cell line, the proportion of wild‐type mtDNA increased from 13% initially to approximately 22% after 5 days in ketogenic medium and was accompanied by a dramatic improvement in mitochondrial protein synthesis. We also present evidence that treatment with ketone bodies caused “heteroplasmic shifting” not only among cells (ie, intercellular selection) but also within cells (ie, intracellular selection). The demonstration that ketone bodies can distinguish between normal and respiratorily compromised cells points to the potential use of a ketogenic diet to treat patients with heteroplasmic mtDNA disorders. Ann Neurol 2004
Electromyography guides toward subgroups of mutations in muscle channelopathies
Authors: Fournier Emmanuel , Arzel Marianne , Sternberg Damien , Vicart Savine , Laforet Pascal , Eymard Bruno , Willer Jean‐Claude , Tabti Nacira , Fontaine Bertrand 
Published: September 2004

AbstractMyotonic syndromes and periodic paralyses are rare disorders of skeletal muscle characterized mainly by muscle stiffness or episodic attacks of weakness. Familial forms are caused by mutations in genes coding for skeletal muscle voltage‐gated ion channels. Exercise is known to trigger, aggravate, or relieve the symptoms. Therefore, exercise can be used as a functional test in electromyography to improve the diagnosis of these muscle disorders. Abnormal changes in the compound muscle action potential can be disclosed using different exercise tests. We report the outcome of an inclusive electromyographic survey of a large population of patients with identified ion channel gene defects. Standardized protocols comprising short and long exercise tests were applied on 41 unaffected control subjects and on 51 case patients with chloride, sodium, or calcium channel mutations known to cause myotonia or periodic paralysis. These tests disclosed significant changes of compound muscle action potential, which generally matched the clinical symptoms. Combining the responses to the different tests defined five electromyographic patterns (I–V) that correlated with subgroups of mutations and may be used in clinical practice as guides for molecular diagnosis. We hypothesize that mutations are segregated into the different electromyographic patterns according to the underlying pathophysiological mechanisms. Ann Neurol 2004
Effect of operation conditions in the pervaporation of ethanol–water mixtures with poly(1‐trimethylsilyl‐1‐propyne) membranes
Authors: González‐Marcos Jose A. , López‐Dehesa Cristina , González‐Velasco Juan R. 
Published: September 2004

AbstractPoly(1‐trimethylsilyl‐1‐propyne) (PTMSP) is known to show preferential permeation of ethanol in the pervaporation of ethanol–water mixture. Although this polymer presents good characteristics for the separation of organic–water solutions, operation conditions and membrane characteristics, such as thickness, affect its pervaporation performance. The effect of temperature and feed concentration on pervaporation was studied. During pervaporation of 10 wt % ethanol–water solution, the separation factor (αH2OEtOH) remains almost constant, whereas the permeation flux (F) increases exponentially with operation temperature. On the other hand, the separation factor decreases, whereas the permeation flux increases with ethanol content in the feed mixture. The membrane thickness also affects the performance of PTMSP polymer films: selectivity increases sharply with membrane thickness up to 50 μm, whereas it remains constant for thicker membranes. The permeation flux decreases with membrane thickness in the whole range studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94:1395–1403, 2004
Preparation of linear low‐density polyethylene by in situ copolymerization of ethylene with Zr supported on montmorillonite/Fe/methylaluminoxane catalyst system
Authors: Zhang Zhicheng , Guo Cunyue , Cui Nannan , Ke Yucai , Hu Youliang 
Published: September 2004

AbstractLinear low‐density polyethylene (LLDPE) was prepared by in situ copolymerization of ethylene with dual‐functional catalysts that were composed of rac‐Et(Ind)2ZrCl2 supported on montmorillonite (MMT) and {[(2‐ArNC(Me))2C5H3N]FeCl2} [Ar = 2,4‐C6H4(Me)2] oligomerization catalyst. A series of polyethylenes with different degrees of branching were obtained by adjusting the ratio of Fe and Zr (Fe/Zr). DSC, NMR, GPC, SEM, and density‐gradient method were used to characterize the polymers. With increasing Fe/Zr ratio, the densities and melting points of polymers decreased, whereas the branching degrees and molecular weights increased. When the Fe/Zr ratio was increased, the activities of the catalysts decreased at atmospheric pressure and increased at 0.7 MPa ethylene pressure. SEM micrographs revealed that the morphology of branched polyethylene, produced with the catalyst supported on MMT, is better than that produced by the catalyst in a homogeneous system. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1690–1696, 2004
The effect of bimodality on the tear properties of filled silicone networks
Authors: Shah Gul Bali 
Published: September 2004

AbstractThe effect of blending a short and a long chain silicone prepolymer, that is, the effect of bimodality on tear properties of filled polymer networks has been investigated. Two concentrations, namely, 17.2 and 30.2% w/w of the filler (HDK) were used. The contents of short chain prepolymers have been varied from 0 to 69% w/w and 0 to 58% w/w for 17.2 and 30.2% filled polymer, respectively. The concentration of crosslinker and catalyst added were kept constant, namely, 13.79 and 0.07%, respectively, for each composition. It has been shown that up to a threshold concentration of filler and short chain prepolymers, the application of bimodality has beneficial effects of increasing tear energy up to 3.5 times that of the tear energy of the concerned filled monomodal polymer network. Above this threshold limit, further increase in concentration of filler or short chain prepolymers, contrary to expectation, adversely affected the tear properties of the filled polymer networks. In light of the results obtained, the mechanism of enhancement in the tear properties of the polymer network due to bimodality in the filled polymer system has been discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1719–1722, 2004
Influence of the method of mixing on homogeneity and crystallization kinetics of blends of linear and branched polyethylene
Authors: Neway B. , Gedde U. W. 
Published: September 2004

AbstractThe influence of mixing method—solution and melt mixing—on the homogeneity and crystallization kinetics of a series of blends of single‐site materials of linear polyethylene and ethyl‐branched polyethylene was studied by differential scanning calorimetry. Data obtained for heats of melting and crystallization, melting and crystallization peak temperatures, and melting and crystallization temperature profiles were essentially the same for the samples obtained by the two mixing methods. The results obtained can be interpreted as indicating that melt mixing is capable of producing homogeneous melts of these relatively low molar mass polymers, given that solution mixing is considered to give perfectly homogeneous blends. The heat associated with the high temperature melting peak after crystallization at 125°C of the blend samples, obtained by the two preparation methods, was higher than that of the linear polyethylene included in the blends, suggesting that a part of the branched polyethylene crystallized at 125°C. The unblended branched polyethylene showed no crystallization at 125°C. Samples obtained by powder mixing showed independent crystallization and melting of the linear and branched polyethylene components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1730–1736, 2004