bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyperhomocysteinemia and deep vein thrombosis in orthotopic heart transplantation: A case report
Authors: Costea Alex , Bhat Geetha
Published: September 2004

Homocysteine has been recognized as a risk factor for atherosclerosis and arterial and venous thrombosis. Heart transplant patients have an increased prevalence of hyperhomocysteinemia. High homocysteine levels in transplant patients may promote development of cardiac allograft vasculopathy, but there is minimal information regarding the risk of venous thrombosis. The current case report illustrates the association of increased levels of homocysteine and hypercoagulable syndrome in a 36‐year‐old heart transplant patient with no previous history of clotting disorder. Both elevated homocysteine levels and extensive venous thrombosis responded promptly to treatment with a folate/B12/B6 vitamin combination and enoxaparin. Am. J. Hematol. 77:161–163, 2004. © 2004 Wiley‐Liss, Inc.
Trisomy 21 is associated with variable defects in cytotrophoblast differentiation along the invasive pathway
Authors: Wright Alexi , Zhou Yan , Weier Jingly Fung , Caceres Eduardo , Kapidzic Mirhan , Tabata Takako , Kahn Madelyn , Nash Carl , Fisher Susan J.
Published: September 2004

Aneuploid cells in the placenta are associated with poor pregnancy outcomes, but the mechanisms are unclear. Here, we examined the cytotrophoblast (CTB) differentiation pathway that leads to uterine invasion in pregnancies complicated by trisomy 21 (T21) as compared with their normal counterparts. Surprisingly, we observed a wide spectrum of T21 effects. Morphologically, some samples appeared near normal, while others had extensive fibrinoid deposition and apoptosis of CTBs at the maternal–fetal interface (confirmed by TUNEL labeling). At a molecular level, the cells' expression of stage‐specific molecules was variably misregulated. At one end of the spectrum, samples with less apoptosis had relatively normal staining patterns. At the other end, samples with extensive apoptosis showed significantly decreased staining for these antigens. Additional studies confirmed that the effects we observed had functional consequences, because the cells exhibited marked phenotypic alterations in vitro, including a large increase in MMP‐9 production, which distinguishes the effects of T21 on CTBs from those of preeclampsia. The morphologic, phenotypic, and functional differences among CTBs from pregnancies complicated by T21 illustrate the importance of the interplay between fetal/placental genotype and maternal influences on pregnancy outcome. Furthermore, our data may explain why a significant number of these pregnancies end in spontaneous abortion while others survive to term. © 2004 Wiley‐Liss, Inc.
Multiple marker analysis at the promoter region of the DRD4 gene and ADHD: Evidence of linkage and association with the SNP −616
Authors: Lowe Naomi , Kirley Aiveen , Mullins Celine , Fitzgerald Michael , Gill Michael , Hawi Ziarih
Published: September 2004

Abnormalities of dopamine neurotransmission have been hypothesized to play an important role in the pathophysiology of attention deficit hyperactivity disorder (ADHD). Support for this has come from numerous association studies on candidate genes including the dopamine D4 receptor gene (DRD4). One of the most replicated associations between ADHD and the dopaminergic system is the 7‐repeat allele of the VNTR polymorphism of this gene. A lack of association between this marker and ADHD has also been reported in several investigations. In the absence of a firm link between the number of the VNTR repeats and the function of the gene, we sought to investigate several additional markers at the 5′‐end of the gene with potential influence on the expression of the DRD4. We observed a significant over transmission of single nucleotide polymorphism (SNP) (χ2 = 7.45, P = 0.008, OR = 1.63). In addition, an excess transmission of the A allele of the −521 SNP was observed, although it did not attain statistical significance (χ2 = 2.14, P = 0.17, OR = 1.25). Linkage disequilibrium (LD) analysis demonstrated a weak level of D' between any of the tested markers implying that this may be a region of high recombination. It also raises the possibility that the new association with ADHD may be independent of the 7‐repeat allele. Further analyses, preferably in samples demonstrating association with the VNTR, or in other ethnic groups, are required to confirm these observations. © 2004 Wiley‐Liss, Inc.
Linkage disequilibrium mapping of bipolar affective disorder at 12q23‐q24 provides evidence for association at CUX2 and FLJ32356
Authors: Glaser Beate , Kirov George , Green Elaine , Craddock Nick , Owen Michael J.
Published: September 2004

Chromosome 12q23‐q24 has been implicated by several linkage studies as harboring a gene for bipolar affective disorder. We performed linkage disequilibrium (LD) mapping with 17 microsatellite markers across a 1.6 Mb‐wide segment forming the central part of our narrowest linkage region. A significant signal (P = 0.0016) was identified for one microsatellite marker in our UK Caucasian case‐control sample (347 cases, 374 controls). Genes, including regulatory elements, around this marker were screened for mutations and the LD structure of the region determined by genotyping 22 SNPs and insertion/deletion polymorphisms in 94 individuals. A set of 11 haplotype tagging (ht) SNPs was genotyped in our sample using a two‐stage procedure. Two SNPs (rs3847953 and rs933399) and an insertion/deletion with putative functional relevance (which are in high LD with each other and with the microsatellite marker) showed significant or nearly significant association with bipolar disorder after Bonferroni‐correction (reaching nominal P values from P = 0.002 to P = 0.005). In a sample of 110 UK Caucasian parent–offspring trios there was a trend for an over transmission in the same direction that failed to meet conventional levels of statistical significance. Our data provide evidence for association between bipolar mood disorder and markers on chromosome 12q23‐q24 but need replication in independent samples. © 2004 Wiley‐Liss, Inc.
Association analysis of NOTCH 4 polymorphisms with schizophrenia among two independent family based samples
Authors: Prasad S. , Chowdari K.V. , Wood J. , Bhatia T. , Deshpande S.N. , Nimgaonkar V.L. , Thelma B.K.
Published: September 2004

The present study investigated polymorphisms of the NOTCH 4 gene in two independent samples from India and USA, consisting of patients with schizophrenia and their parents (n = 182, and n = 148 ‘trios,’ respectively). Five DNA markers, namely (GAAG)n, (TAA)n, SNP1, SNP2, and (CTG)n were evaluated. Transmission distortion, consistent with a modest association was detected among both samples. Additional association studies at this locus are warranted. © 2004 Wiley‐Liss, Inc.
Association study of neurotrophic tyrosine kinase receptor type 2 (NTRK2) and childhood‐onset mood disorders
Authors: Adams Jennifer H. , Wigg Karen G. , King Nicole , Burcescu Irina , Vetró Ágnes , Kiss Eniko , Baji Ildikó , George Charles J. , Kennedy James L. , Kovacs Maria , Barr Cathy L.
Published: September 2004

Childhood‐onset mood disorders (COMD) are often familial, and twin studies of COMD provide compelling evidence that genetic factors are involved. Deficits in neural plasticity have been suggested to underlie the development of depression. The receptor tropomyosin related kinase B (TrkB) and its ligand, brain derived neurotrophic factor (BDNF), play essential roles in neural plasticity, and mRNA expression of both of these genes has been shown to be influenced by stress and chronic antidepressant treatment. In addition, TrkB knock‐out mice display inappropriate stress coping mechanisms. Having previously shown that BDNF is associated with COMD, in this study we investigated the gene encoding TrkB, neurotrophic tyrosine kinase, receptor, type 2 (NTRK2) as a susceptibility factor in COMD. We tested for association of NTRK2 with COMD in two independent samples: (a) a case‐control sample matched on ethnicity and gender, consisting of 120 cases who met DSM III/IV criteria for major depressive or dysthymic disorder before age 14 or bipolar I/II before the age of 18, and controls, and (b) a family based control sample of 113 families collected in Hungary, identified by a proband between the age of 7 and 14 who met DSM IV criteria for major depressive disorder or bipolar I/II disorder. There was no evidence for an allelic or genotypic association of three polymorphisms of NTRK2 with COMD in the case‐control sample. Also, in the family based sample, using the transmission disequilibrium test (TDT), we did not identify any evidence of allelic association for each marker individually or when haplotypes were analyzed. Based on these results, using these three polymorphisms, we do not find support for NTRK2 as a susceptibility gene for COMD. © 2004 Wiley‐Liss, Inc.
Association of the −141C Del variant of the dopamine D2 receptor (DRD2) with positive family history and suicidality in German alcoholics
Authors: Johann Monika , Putzhammer Albert , Eichhammer Peter , Wodarz Norbert
Published: September 2004

Several lines of evidence indicate an involvement of the dopaminergic system in alcoholism, withdrawal, suicidality, and attention‐deficit hyperactivity disorder (ADHD). The functionally relevant −141C Ins/Del polymorphism located upstream to exon 1 in the 5′‐region of the dopamine D2 receptor (DRD2) gene might be an interesting candidate gene. We investigated a sample of 1,126 well‐characterized, primary chronic alcoholics of German descent according to a phenotype–genotype strategy, i.e., alcoholics suffering from severe withdrawal complications such as seizure or delirium, family history positive (FH+) alcoholics, alcoholics with an antisocial personality disorder (ASPD), alcoholics with an ADHD, and type 1 or type 2 alcoholics according to Cloninger's typology. Compared to the control subjects, there was a significant excess of the −141C Del allele in alcoholics with a paternal and grandpaternal history of alcoholism and in alcoholic subgroups with suicidality or without a history of withdrawal symptoms. There were no significant differences in allele frequency between the entire group or subgroups of alcoholics and healthy controls. Therefore, the −141C Del variant of the DRD2 might be a protective factor against the development of withdrawal symptoms. However, it might also be a risk factor in a highly burdened subgroup of alcoholics with a paternal and grandpaternal history of alcoholism and it might contribute to the substantially higher likelihood of suicide in alcoholics. © 2004 Wiley‐Liss, Inc.
APOE and other loci affect age‐at‐onset in Alzheimer's disease families with PS2 mutation
Authors: Wijsman Ellen M. , Daw E. Warwick , Yu Xuesong , Steinbart Ellen J. , Nochlin David , Bird Thomas D. , Schellenberg Gerard D.
Published: September 2004

Several kindreds of Volga German (VG) ancestry have a single PS2 mutation that causes an autosomal dominant form of Alzheimer's disease (AD). These families show a wide range in age‐at‐onset, which suggests the existence of modifying factors other than the PS2 mutation. To examine evidence for a genetic basis of variation in onset age, we performed a Bayesian oligogenic segregation and linkage analysis on nine VG families confirmed to have at least one affected PS2 carrier. This analysis simultaneously estimated the effects of APOE and PS2 and the number and effects of additional loci affecting AD age‐at‐onset. In addition, a family effect accounted for shared environmental effects. This analysis approach has the advantage of full use of the complete pedigree structure, as well as use of information on unsampled individuals with phenotypic data. These analyses provide evidence that APOE plays a small, but significant, role in modifying the age‐at‐onset in these VG families. The effects estimated for the APOE ε3 and ε4 genotypes were consistent with those estimated in previous analysis of late‐onset AD families, with evidence for a dose‐dependent relationship between number of ε4 alleles and age‐at‐onset. We estimated an ∼83% posterior probability of at least one modifier locus in addition to APOE, and that the fraction of the variance in age‐at‐onset attributable to PS2, APOE, other loci, and family effects is ∼70, ∼2, ∼6.5, and ∼8.5%, respectively. These results provide evidence that APOE and other loci modify onset in AD caused by PS2 mutation. © 2004 Wiley‐Liss, Inc.
DAT1, DRD4, and DRD5 polymorphisms are not associated with ADHD in Dutch families
Authors: Bakker Steven C. , van der Meulen Emma M. , Oteman Nicole , Schelleman Hedi , Pearson Peter L. , Buitelaar Jan K. , Sinke Richard J.
Published: September 2004

Recent meta‐analyses have indicated that the dopamine transporter gene (DAT1) and the dopamine receptor genes D4 (DRD4) and D5 (DRD5) are associated with attention‐deficit hyperactivity disorder (ADHD), although single studies frequently failed to show significant association. In a family‐based sample of 236 Dutch children with ADHD, we have investigated the previously described variable number of tandem repeat (VNTR) polymorphisms and two additional microsatellites at the DAT1 and DRD4 loci. DRD5 was investigated using the microsatellite that was previously found to be associated. Transmission disequilibrium tests (TDTs) did not show preferential transmission of alleles or two‐marker haplotypes to affected offspring. These data suggest that DAT1, DRD4, and DRD5 do not contribute substantially to ADHD in the Dutch population. © 2004 Wiley‐Liss, Inc.
A genome scan of neuroticism in nicotine dependent smokers
Authors: Neale Benjamin M. , Sullivan Patrick F. , Kendler Kenneth S.
Published: September 2004

Neuroticism is a personality factor that has consistently been demonstrated to be associated with anxiety, depression, and other “internalizing” disorders. We analyzed a genome scan for neuroticism on a sample of 129 sib‐pair families (113 with a single sibling pair, 18 with multiple sibling pairs) containing a total of 201 possible sibling pairs, ascertained for concordance on nicotine dependence. Using Merlin‐Regress, we replicated peaks for neuroticism described by prior studies, on chromosomes 1 and 11 with LOD scores of 2.52 and 1.97 (P‐value of 0.003 and 0.0108) respectively, and have some evidence for a novel finding on chromosome 12 with a LOD of 2.85 (P‐value of 0.0014). © 2004 Wiley‐Liss, Inc.
Brain perfusion and dopaminergic genes in boys with attention‐deficit/hyperactivity disorder
Authors: Szobot Claudia , Roman Tatiana , Cunha Renato , Acton Paul , Hutz Mara , Rohde Luis Augusto
Published: September 2004

Neuroimaging studies have suggested the involvement of several brain areas in attention‐deficit/hyperactivity disorder (ADHD). Genetic investigations have supported the role of both dopamine D4 receptor gene (DRD4) and dopamine transporter gene (DAT1) in the vulnerability to the disorder. This study evaluates whether the presence of risk alleles at DRD4 and/or DAT1 genes is associated with differences in regional cerebral blood flow (rCBF) in a sample of ADHD boys. The rCBF was compared between ADHD patients with and without risk alleles at DRD4 (7‐repeat allele) and/or at DAT1 (homozygosis for the 10‐repeat allele) genes by single photon emission computed tomography (SPECT) during continuous performance test. Images were analyzed using statistical parametric mapping (SPM‐99). No significant differences in rCBF were found both between ADHD boys with and without the 7‐repeat allele at DRD4 locus, as well as between ADHD boys homozygous for the 10‐repeat allele and ADHD subjects with other genotypes at the DAT1 locus. However, a significantly higher perfusion in the right middle temporal gyrus was found in the group with risk alleles at both DRD4 and DAT1 loci (n = 6) compared to ADHD boys without risk alleles at both loci (n = 28) (P < 0.05). Our findings suggest that a higher recruitment in middle temporal gyrus, an area associated to working memory and selective attention, should exist to compensate a putative effect of the interaction between these dopaminergic genes. © 2004 Wiley‐Liss, Inc.
MCP‐1 gene (SCYA2) and schizophrenia: A case‐control association study
Authors: Mundo Emanuela , Altamura A. Carlo , Vismara Serena , Zanardini Roberta , Bignotti Stefano , Randazzo Roberto , Montresor Claudio , Gennarelli Massimo
Published: September 2004

Dysregulation of the inflammatory response system has been linked to the pathophysiology of schizophrenia. Abnormal levels of proinflammatory cytokines and their receptors have been found in peripheral blood and cerebrospinal fluid of schizophrenic patients, suggesting the presence of immune activation. Monocyte chemoattractant protein 1 (MCP‐1) influences the expression of cytokines related to T helper responses. MCP‐1 also exerts several effects on monocytes, including the expression of several proinflammatory genes. The A‐2518G polymorphism of the MCP‐1 gene (SCYA2) appears to affect the transcriptional activity and monocyte MCP‐1 production. The aim of this case‐control study was to investigate the potential role of SCYA2 (A‐2518G polymorphism) in conferring susceptibility to schizophrenia and to the resistance to antipsychotic treatment. The sample studied consisted of 191 DSM‐IV schizophrenia or schizoaffective disorder (depressive subtype) patients and 161 matched healthy controls. No significant genotypic (χ2 = 0.278, df = 2, P = 0.986) or allelic (χ2 = 0.021, df = 1, P = 0.884) association was found between the A‐2518G variant of the SCYA2 and the diagnosis. No differences in the age at onset of schizophrenia were found between the three genotype groups identified. Significant genotypic association was found between the A‐2518G variant of the SCYA2 and the resistance to antipsychotic treatment (χ2 = 6.26, df = 2, P = 0.04), with resistant patients more frequently carrying the G allele. The odds ratio associated to the presence of the G allele was 2.39 (95% CI = 1.14–4.98). These data suggest that the A‐2518G variant of the SCYA2 has not a major role in the pathogenesis of schizophrenia, while it could be implicated in the resistance to antipsychotic treatment. © 2004 Wiley‐Liss, Inc.
Magnetic characterization of cobalt nanoparticles by temperature‐dependent magnetic relaxation measurements
Authors: Romanus E. , Matoussevitch N. , Prass S. , Heinrich J. , Müller R. , Berkov D. V. , Bönnemann H. , Weber P.
Published: September 2004

A recently introduced method for the characterization of magnetic nanoparticles based on the analysis of the dependence of the Néel relaxation signal on the sample temperature (temperature‐dependent magnetorelaxometry, TMRX) has been applied to characterize air‐stable cobalt particles made by decomposition of Co2(CO)8 in the presence of aluminium‐organic compounds. The influence of small changes in the preparation process on the magnetic relaxation behaviour has been studied.

A mean magnetically relevant particle size has been derived from TMRX, zero‐field cooled magnetisation and low‐temperature coercivity measurements and has been compared with a mean physical size determined by transmission electron microscopy investigations. Copyright © 2004 John Wiley & Sons, Ltd.
Cure kinetics of epoxy/anhydride nanocomposite systems with added reactive flame retardants
Authors: Torre L. , Lelli G. , Kenny J. M.
Published: September 2004

Montmorillonite nanocomposite systems obtained from epoxy cured using anhydride and the addition of a reacting flame retardant are studied in this paper. In particular, a thermokinetic analysis of the behavior of five different compounds was performed, using a differential scanning calorimeter. The isothermal tests showed double reaction peaks, due to the cure reactions of DGEBA/acid anhydride systems. The comparisons between dynamic thermograms (and between isothermal ones, too) for the different mixtures also showed that the addition of other active substances (such as a nanofiller or a flame retardant additive) does not change the mechanism of crosslinking from a qualitative point of view, but both the nanoreinforcement and the flame retardant seemed to exert an evident catalytic action on the cure reactions. A model describing the cure behavior of the aforementioned materials is proposed in this work. This model takes into account the fact that the reaction mechanism of each analyzed system is composed of a couple of parallel phenomena: the fast opening of anhydride ring (corresponding to a first exothermic peak and characterized by “n‐th order” kinetics) and resin networking (corresponding to a second exothermic peak and characterized by an “auto‐catalytic with zero initial velocity” behavior). The verification of the proposed model was performed by means of a comparison between experimental data (normalized curves derived from DSC thermograms) and theoretical data (derived from a numerical integration—using the second order Runge–Kutta method—of the model‐representative equation) and provided very good results. This allows one to apply such a model to any engineering process problem concerning the cure of DGEBA/acid anhydride/phyllosilicate nanocomposite systems. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1676–1689, 2004
Kinetic expression for the isothermal crystallization of poly(3‐hydroxybutyrate)–11%poly(3‐hydroxyvalerate)
Authors: Cyras Viviana P. , Rozsa Chavati , Galego Norma , Vázquez Analía
Published: September 2004

The use of polyhydroxyalkanoates as a biodegradable semicrystalline polymer is currently increasing. The prediction of crystallinity profiles produced in part with this polymer requires the knowledge of the kinetic expression. In the present article, a kinetic expression of the isothermal melt crystallization of poly(3‐hydroxybutyrate)–11%poly(3‐hydroxyvalerate) [P(HB‐co‐11%HV)] was studied in two temperature ranges, close to the melting point and close to the glass transition. Melting behavior and molecular mobility of the amorphous phase were analyzed as a function of crystallization temperatures by performing calorimetric experiments. The Avrami equation was used and the activation energy of the crystal nucleation and growth were obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1657–1661, 2004
Free radical polymerization kinetics of monomers functionalized with AsO(OH)2 in aqueous media
Authors: Percino M. J. , Chapela V. M. , Jiménez A.
Published: September 2004

The free radical polymerization kinetics of the isomer sodium salts of o‐ and p‐methacryloylaminophenylarsonate in aqueous solution have been studied using a dilatometric method. The polymerizations, initiated with potassium persulfate, were carried out at a constant monomer initial concentration of 0.50 mol/L and the initiator initial concentration was fixed at one of the following: 1.00, 2.00, 5.00, 8.00, or 10.00 (× 10−3 mol/L). Another set of polymerizations were carried out at a constant initiator initial concentration of 2 × 10−3 mol/L and the monomer initial concentration was fixed at one of the following: 0.20, 0.30, 0.50, 0.70, or 1.00 (mol/L). The polymerization reactions were conducted isothermally at 70°C. The order with respect to initiator was consistent with the classical kinetic rate equation, while the order with respect to monomer was greater that unity. The effects of temperature on the polymerization rate were also investigated and the activation energy gave values of 20.66, 22.68, and 23.22 kcal mol−1 K−1 over a temperature range of 50–70°C. For the case of o‐methacryloylaminophenylarsonic acid monomer, its kinetic study was carried out in DMF as solvent and AIBN initiator. p‐Methacryloylaminophenylarsonic acid was too insoluble in DMF to be studied. The polymers obtained were characterized by H‐NMR, IR, and viscosity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1662–1669, 2004
Synthesis and properties of collagen/polylactic acid blends
Authors: Yang Xiaoqiang , Yuan Minglong , Li Wei , Zhang Gaoyong
Published: September 2004

Polylactic acid (PLA) is a biodegradable aliphatic polyester that is suitable for use in many fields related to medical treatment. This article reviews the glass transition temperature (Tg), the biodegradable rate of PLA blended with collagen (Col), and its mechanical properties through tensile, bending and impact testing, thermal analysis (DSC), scanning electron microscopy (SEM), and enzymatic hydrolysis. The results of the mechanical and SEM examination demonstrated partial biocompatibility. The Tg and crystallinity (xc) of the blends decreased with increasing collagen content. The tensile strength and bending strength changed from 53.826Mpa and 102.261Mpa to 11.707Mpa and 24.994Mpa, respectively. It was also found that the enzymatic hydrolysis rate of PLA increased with increasing collagen content. The weight of the blends decreased to half of the original weight after more than five weeks. Viscosity([η]) and molecular weight (Mv) changed slowly in the period of enzymatic hydrolysis. It was concluded that the introduction of the collagen phase clearly diminished the mechanical properties of PLA, but the biodegradable property was improved. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1670–1675, 2004
Performance of crystallization analysis fractionation and preparative fractionation on the characterization of γ‐irradiated low‐density polyethylene
Authors: Vilaplana Francisco , Morera‐Escrich Vanesa , del Hierro‐Navarro Pilar , Monrabal Benjamín , Ribes‐Greus Amparo
Published: September 2004

The effects of γ‐radiation on a low‐density polyethylene (LDPE) were investigated by novel techniques, such as crystallization analysis fractionation and preparative fractionation, to analyze and compare their performance with other analytical procedures such as DSC, FTIR, and GPC. The LDPE was thus irradiated with four different doses of γ‐radiation. Different fractions were obtained from these irradiated materials by preparative fractionation, which were characterized by the above‐mentioned analysis techniques. The changes in the morphology and chemical structure of LDPE after the irradiation were analyzed and it was found that both oxidative scission and crosslinking are phenomena related to the exposure of LDPE at high‐energy radiation. Crystallization analysis fractionation and preparative fractionation proved to be suitable techniques to characterize the effects of γ‐radiation on a low‐density polyethylene material. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1803–1814, 2004
Mechanical and thermal properties of poly(lactic acid)/starch blends with dioctyl maleate
Authors: Zhang Jian‐Feng , Sun Xiuzhi
Published: September 2004

Poly(lactic acid) (PLA)/starch blends were prepared blending with dioctyl maleate (DOM). DOM acted as a compatibilizer at low concentrations (below 5%), and markedly improved tensile strength of the blend. However, DOM functioned as a plasticizer at concentrations over 5%, significantly enhancing elongation. Compatibilization and plasticization took place simultaneously according to the analysis of, for example, mechanical properties and thermal behavior. With DOM as a polymeric plasticizer, thermal loss in the blends was not significant. Water absorption of PLA/starch blends increased with DOM concentration. DOM leaching in an aqueous environment was inhibited. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1697–1704, 2004
X‐ray photoelectron spectroscopy investigation into thermal degradation and stabilization of polyacrylonitrile fibers
Authors: Wu Gangping , Lu Chunxiang , Wu Xueping , Zhang Shouchun , He Fu , Ling Licheng
Published: September 2004

Polyacrylonitrile copolymer fibers have been heated in air to different maximum heat treatment temperatures (MHTT) from 190 to 270°C. The functionalities of C, O, and N in the precursors were determined by X‐ray photoelectron spectroscopy. The intensity of the C1s spectra line 286.8ev, which is identified as C‐O and C = N functionalities, was found to initially increase and suddenly decrease above 230°C. Additionally, the significant broadening of the N1s spectra line was also observed at the same MHTT. It is suggested that some oxygen was incorporated into the six‐member heterocyclic structures that formed by cyclization of nitrile groups and transformed into pyrrole‐type structures by the elimination of carbon monoxide. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1705–1709, 2004
Study on molecular chain heterogeneity of linear low‐density polyethylene by cross‐fractionation of temperature rising elution fractionation and successive self‐nucleation/annealing thermal fractionation
Authors: Kong Jie , Fan Xiaodong , Xie Yunchuan , Qiao Wenqiang
Published: September 2004

The molecular chain heterogeneity of commercial linear low‐density polyethylene (LLDPE) was investigated by cross‐fractionation of temperature rising elution fractionation (TREF) and successive self‐nucleation/annealing (SSA) thermal fractionation by use of DSC. The results indicate that the linear relationships between crystallinity or melting temperature and the elution temperature are confirmed by TREF fractions. Intermolecular heterogeneity exists in the original LLDPE, whereas there is less intermolecular heterogeneity in the TREF fractions. After SSA thermal fractionation, the multiple endothermic peaks for both LLDPE and their TREF fractions are mainly attributed to the heterogeneities of ethylene sequence length (ESL) and lamellar thickness. The statistical terms, including weighted mean Lw, arithmetic mean Ln, and broad index Lw/Ln, were introduced to evaluate the heterogeneities of ESL and lamellar thickness of polyethylene. The difference of broadness index indicates that TREF fractions of LLDPE have less inter‐ and intramolecular heterogeneities of both ESL and lamellar thickness than those of the original LLDPE. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1710–1718, 2004
Aqueous polyurethane dispersions derived from polycarbonatediols
Authors: Lee Da‐Kong , Tsai Hong‐Bing , Wang Hsine‐Hsyan , Tsai Ruey‐Shi
Published: September 2004

Aqueous polyurethane dispersions derived from polycarbonatediols, isophorone diisocyanate, and carboxylic diols including dimethylol propionic acid and dimethylol butyric acid were prepared. The effect of dispersing procedure is investigated by FT IR, GPC, and the tensile film properties. The polyurethane dispersions prepared by a standard procedure exhibit lower molecular weights due to the overhydrolysis of the NCO groups. The polyurethane dispersions prepared by a modified procedure exhibit significantly higher molecular weights due to more effective chain extension, and their cast films exhibit higher tensile strength. The particle size, tensile properties, thermal properties, and dynamic mechanical properties are investigated. The chemical structure of the polycarbonatediols seems to affect the tensile strength. The glass transition temperature of the soft segments, Tg(S), of the polyurethane dispersions can be seem from the DSC and DMA data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1723–1729, 2004
Separation of endocrine disruptors from aqueous solutions by pervaporation: Dioctylphthalate and butylated hydroxytoluene in mineral water
Authors: Higuchi Akon , Yoon Boo Ok , Kaneko Takayuki , Hara Mariko , Maekawa Maya , Nohmi Takashi
Published: September 2004

We examined the existence of endocrine disruptors in mineral water, ultrapure water, and tap water. GC/MS analysis revealed that dioctylphthalate (di‐n‐octylphthalate and di(2‐ethylhexyl)phthalate) in the water was found to be on the order of parts per billion. The dioctylphthalate concentration remained consistent for mineral water of the same brand, regardless of whether it was bottled in a PET bottle or a glass bottle. Therefore, the dioctylphthalate contamination in mineral water originated from the manufacturing line of the mineral water and not as a result of leaching from PET bottles. Butylated hydroxytoluene (BHT), an oxidization prevention agent in plastics, was detected at 2.05 ± 0.1 ppb in the mineral water bottled in glass bottles, but was not detected in the mineral water bottled in PET bottles. BHT contamination in the mineral water in the glass bottles is likely to have originated from the cap of the glass bottles, as the caps were sealed with polyethylene. We further investigated the feasibility of separating dioctylphthalate and BHT from the mineral water by pervaporation using hydrophobic polydimethylsiloxane membranes. We found that trace amounts (on the order of parts per billion) of organic chemicals such as dioctylphthalate and BHT in aqueous solutions can be removed and concentrated by the pervaporation using polydimethylsiloxane membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1737–1742, 2004
Preparation and properties of waterborne poly(urethane urea)s for adhesives: The effects of the 2,2‐bis(hydroxylmethyl)propionic acid content on the properties
Authors: Kwak Yong Sil , Kim Eun Young , Ha Yoo Byung , Kim Han Do
Published: September 2004

A series of waterborne poly(urethane urea)s (WBPUs) containing various concentrations (8.3–15.5 mol %) of 2,2‐bis(hydroxylmethyl)propionic acid (DMPA) were prepared from isophorone diisocyanate, poly(tetramethylene adipate) glycol, DMPA, ethylenediamine, and triethylamine. The length of the hard segment with the DMPA content was varied from 18.7 to 22.6 wt % at a fixed soft‐segment length (2000 g/mol). The effect of the DMPA content on the colloidal properties of WBPU dispersions, the hydrogen‐bonding index, water swelling, dynamic mechanical thermal properties, and mechanical properties of WBPU films, and the adhesive strengths of substrates such as chloroprene rubber (CR)/CR, CR/polyurethane foam, CR/ethylene vinyl acetate foam, and thermoplastic olefin sheet/polypropylene foam were investigated. Stable aqueous dispersions of WBPU were obtained when the DMPA concentration was greater than 10 mol %. As the DMPA content increased, the particle size of the WBPU dispersion decreased, but the viscosity of the WBPU dispersion increased. The hydrogen‐bonding fraction, water swelling, dynamic storage modulus and relaxation temperature, and tensile strength of the films increased with increasing DMPA content. According to an adhesion test, the substrates adhering to WBPU with greater than 10 mol % DMPA tore at about 8.0 kgf/cm2 instead of breaking the adhered region. These results suggested that the WBPUs prepared in this study could have potential for adhesive use. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1743–1751, 2004
Simple chemical polymerization method for the deposition of a conducting polyaniline on the surface of acrylonitrile–butadiene–styrene. II. Treatment in organic free solvent
Authors: Matveeva E. , Carrascosa R. Enguix , Martínez Palomino R. J. , Parkhutik V.
Published: September 2004

We developed a simple method for the deposition of a uniform layer of polyaniline (PANI) on the surface of acrylonitrile–butadiene–styrene (ABS). The method consisted of two steps: the soaking of ABS samples in a water‐based aniline solution stabilized by surfactants followed by the oxidative polymerization of the adsorbed and absorbed monomer. The three types of surfactants (molecular N,N‐dimethyl‐octalamine‐N‐oxide, anionic sodium dodecyl sulfate, and cationic hexadecyl trimethyl ammonium bromide) were used to prepare and stabilize the aniline emulsions in water. After treatment, the ABS surface was completely covered by PANI (as seen with scanning electron microscopy). The surface conductivity after PANI coating reached values between 10−3 and 10−4 S/□ in the best developed conditions. The chemical nature of the surfactant affected the particular setting of the aniline/surfactant emulsion preparation (time of ultrasonification = 15–30 min), its optimal concentration (2–10 wt % aniline and 0.1–0.2M surfactant), and other parameters of treatment, such as time (10 s to 20 min) and temperature (20–60°C) of soaking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1752–1758, 2004
Viscosity/molecular‐weight relationship for γ‐(2,3‐dihydroxypropoxy)propyl‐terminated poly(dimethylsiloxane)s
Authors: Feng Shengyu , Zhang Jie , Wang Dake , Wu Mingyan , Yu Zhaotan
Published: September 2004

A series of γ‐(2,3‐dihydroxypropoxy)propyl‐terminated poly(dimethylsiloxane) (DHT‐PDMS) samples with different molecular weights were prepared through the acid‐catalyzed equilibrium copolymerization of octamethylcyclotetrasiloxane and 1,3‐bis[γ‐(2,3‐dihydroxypropoxy)propyl]tetramethyldisiloxane. The intrinsic viscosity in toluene ([η]toluene) and the number‐average molecular weight (Mn) were determined with an Ubbelohde viscometer and 1H‐NMR spectra, respectively. In this way, the relationship between [η]toluene and Mn was established. For 2.0 × 104 < Mn < 4.0 × 104, [η]toluene,25°C was 1.874Mn 0.323. The solution behavior of DHT‐PDMS was also investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1759–1762, 2004
Use of a sodium ionomer as a compatibilizer in polypropylene/high‐barrier ethylene–vinyl alcohol copolymer blends: The processability of the blends and their physical properties
Authors: Abad M. J. , Ares A. , Barral L. , Cano J. , Díez F. J. , García‐Garabal S. , López J. , Ramírez C.
Published: September 2004

The effect of a sodium ionomer (ion.Na+) on the compatibility of polypropylene (PP)/high‐barrier ethylene–vinyl alcohol copolymer (EVOH) blends was studied in terms of the thermal, mechanical, and optical properties and morphology. The rheological behavior, tensile tests, and morphology of the binary blends showed that the miscibility of EVOH with PP was very poor. The miscibility of the polymers improved with the ionomer addition. In general, the ion.Na+ concentration did not alter the thermal behavior of the blends, but it did improve the ductility of the injection‐molded specimens. Scanning electron micrographs displayed better adhesion between the PP and EVOH phases in the samples with the ionomer. The mechanical improvement was better in the film samples than in the injection‐molded samples. A 90/10 (w/w) PP/EVOH film with 5% ion.Na+ and an 80/20 (w/w) PP/EVOH film with 10% ion.Na+ presented better global properties than the other blends studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1763–1770, 2004
Synthesis and analytical application of a chelating resin based on a crosslinked styrene/maleic acid copolymer for the extraction of trace‐metal ions
Authors: Roy P. K. , Rawat A. S. , Choudhary V. , Rai P. K.
Published: September 2004

A new chelating polymer sorbent was synthesized through the copolymerization of styrene and maleic anhydride in the presence of divinyl benzene as the crosslinking agent, followed by hydrolysis. This polymeric resin, bearing O donor groups, had the advantage of being stable in basic and saline media, unlike its linear analogue. This newly developed chelating matrix has a high resin capacity for metal ions such as Cr, Fe, Ni, Cu, and Pb. Various physicochemical parameters, such as the pH, volume, and flow rate, and the interference effect on metal uptake were studied. The sorption capacities of the crosslinked resin for Cr(III), Fe(III), Ni(II), Cu(II), and Pb(II) were 10.2, 14.3, 14.2, 15.4, and 8.8 mg/g, respectively. A high recovery of 98% was obtained for all the metal ions with 2N HCl as the eluting agent. The chelating resin was characterized by swelling studies, Fourier transform infrared, elemental analysis, X‐ray studies, and thermal analysis. The Langmuir and Freundlich adsorption isotherms were used to validate the metal‐uptake data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1771–1779, 2004
Mechanical and thermal properties of ceramic‐modified poly(amide imide)
Authors: Park Young‐Wook , Lee Dong‐Sung
Published: September 2004

Poly(amide imide)–epoxysilane (coupling agent) composites were reacted with silica, a condensation product of tetraethylorthosilicate (TEOS), by a sol–gel process and were then cast into films. After this procedure, the chemical characteristics and mechanical and thermal properties were measured. Fourier transform infrared showed that silica existed in the poly(amide imide) matrix. When a proper amount of silica was added to the poly(amide imide) matrix, the tensile strength, elongation, and toughness increased greatly. A poly(amide imide)/30 wt % epoxysilane composite with 20 wt % TEOS had the best mechanical properties. Thermogravimetric analysis under nitrogen and oxygen atmospheres indicated that the char contents increased with the amount of silica. The glass‐transition temperatures of the poly(amide imide)–silica nanocomposites were observed around 170–180°C with differential scanning calorimetry. This approach may be a new method for the low‐temperature thermal curing of poly(amide imide). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1780–1788, 2004
Synthesis and characterization of diblock, triblock, and multiblock copolymers containing poly(3‐hydroxy butyrate) units
Authors: Arslan Hülya , Menteş Ayfer , Hazer Baki
Published: September 2004

A poly[(R,S)‐3‐hydroxybutyrate] macroinitiator (PHB‐MI) was obtained through the condensation reaction of poly[(R,S)‐3‐hydroxybutyrate] (PHB) oligomers containing dihydroxyl end functionalities with 4,4′‐azobis(4‐cyanopentanoyl chloride). The PHB‐MI obtained in this way had hydroxyl groups at two end of the polymer chain and an internal azo group. The synthesis of ABA‐type PHB‐b‐PMMA block copolymers [where A is poly(methyl methacrylate) (PMMA) and B is PHB] via PHB‐MI was accomplished in two steps. First, multiblock active copolymers with azo groups (PMMA‐PHB‐MI) were prepared through the redox free‐radical polymerization of methyl methacrylate (MMA) with a PHB‐MI/Ce(IV) redox system in aqueous nitric acid at 40°C. Second, PMMA‐PHB‐MI was used in the thermal polymerization of MMA at 60°C to obtain PHB‐b‐PMMA. When styrene (S) was used instead of MMA in the second step, ABCBA‐type PMMA‐b‐PHB‐b‐PS multiblock copolymers [where C is polystyrene (PS)] were obtained. In addition, the direct thermal polymerization of the monomers (MMA or S) via PHB‐MI provided AB‐type diblocks copolymers with MMA and BCB‐type triblock copolymers with S. The macroinitiators and block copolymers were characterized with ultraviolet–visible spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, cryoscopic measurements, and thermogravimetric analysis. The increases in the intrinsic viscosity and fractional precipitation confirmed that a block copolymer had been obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1789–1796, 2004
Poly(oxyethylene)diamine‐derived hydrophilic copolymers for emulsifying diglycidylether of bisphenol‐A
Authors: Lin Jiang‐Jen , Chen Shi‐Min , Hu Shang‐Siou
Published: September 2004

A series of reactive surfactants were synthesized by the reaction of hydrophilic poly(oxyethylene)diamines of 2000–6000 g/mol molecular weight and diglycidylether of bisphenol‐A resin. The synthesized surfactants consisted of multiple functionalities including tertiary amines, hydrophobic alkylphenoxys, and reactive oxirane groups. After treatment with hydrochloric acid, the surfactants consisted of two different hydrophilic groups: cationic quaternary ammonium salts and nonionic oxyethylene segments. By prudent selection of the proper hydrophile–lipophile balance, the surfactant can be highly effective for solubilizing the epoxy resin in water to form a stable emulsion at a fine particle size of 350 nm. Another advantage is that the surfactant may participate in a curing process through the built‐in oxirane reaction and become a nonextractable component in polymer matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1797–1802, 2004
Computer simulation and comparative study on the pervaporation separation characteristics of sodium alginate and its blend membranes with poly(vinyl alcohol) to separate aqueous mixtures of 1,4‐dioxane or tetrahydrofuran
Authors: Aminabhavi Tejraj M. , Vijaya Kumar Naidu B. , Sridhar S.
Published: September 2004

A comparative study on the pervaporation separation has been attempted for water + 1,4‐dioxane and water + tetrahydrofuran mixtures using sodium alginate and blend membranes of sodium alginate with 5, 10, and 20 mass % of poly(vinyl alcohol). Pure sodium alginate membrane has a selectivity of 111 to water at 0.35‐mol fraction of water in the feed mixture containing 1,4‐dioxane while for water + tetrahydrofuran mixture, the membrane selectivity to water was 291 at 0.31‐mol fraction of water in the feed mixture. Pervaporation results have been discussed using the solution–diffusion principles. Arrhenius activation parameters for diffusion and permeation have been computed from the temperature‐dependent pervaporation results. Furthermore, experimental results have been analyzed using the complete mixing and plug flow models to compute membrane area as well as design parameters that are useful in scale‐up operations. The plug flow model is more appropriate than the complete mixing model to analyze the pervaporation results. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1827–1840, 2004
Poly(propylene)/poly(ethylene terephthalate‐co‐isophthalate) blends and glass bead filled composites: Microstructure and thermomechanical properties
Authors: Arencón D. , Velasco J. I. , Rodríguez‐Pérez M. A. , de Saja J. A.
Published: September 2004

Blends of poly(propylene) (PP) and poly(ethylene terephthalate‐co‐isophthalate) (co‐PET) (95/5) with and without compatibilizing agent (maleic anhydride PP), as well as composites of these blends with glass beads (50 wt%) with and without silane coupling agent surface‐treatment, were prepared and studied on a basis of the material microstructure and thermomechanical properties. Infrared and Raman spectroscopy, as well as transmission electron microscopy, displayed evidence of MAPP compatibilizing action for the blend. Differential scanning calorimetry showed a remarkable effect of nucleation rate increase exerted by co‐PET on the PP crystallization. Moreover, glass beads were found to increase the PP nucleation rate slightly. PP crystallinity hardly varied with the composition. Wide angle X‐ray diffraction allowed determination of differences in the orientation of the poly(propylene) b‐axis, with more homogeneous orientations in the presence of both co‐PET and glass beads. MAPP promoted the PP b‐axis orientation. Differences in PP α′ relaxation could be analyzed through dynamic‐mechanical thermal analysis (DMTA). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1841–1852, 2004
Innovation zur Bestimmung der Erdstoff‐Geokunststoff‐Wechselwirkung – Pullout‐, Scher‐ und Reibungsversuche
Authors: Aydogmus Taner , Klapperich Herbert
Published: September 2004

Der Einsatz des ökonomischen und ökologischen Baumaterials “Geokunststoff” hat sich in den letzten Jahren in der Geotechnik für das Bauwesen, den Bergbau und den Umweltschutz stark verbreitet. In Form von Geotextilien, Geogittern, Geomembranen und verwandten Produkten ermöglichen sie technisch einfache, preisgünstige alternative Lösungsmöglichkeiten. Für die Berechnung der Standsicherheit von Konstruktionen mit Geokunststoffen, die für Bewehrungszwecke verwendet werden, ist die Ermittlung der “Reibungseigenschaften” in den Schichtgrenzen zwischen verschiedenen Geokunststoffen sowie zwischen Geokunststoffen und Erdstoffen unerläßlich. Zur Einschätzung der Hauptversagensmechanismen eines kunststoffbewehrten Erdkörpers werden üblicherweise Scher‐ und Reibungsversuche sowie nun auch verstärkt Pullout‐Versuche durchgeführt. In diesem Beitrag wird ein neu entwickeltes und gebautes vollautomatisches Großrahmenschergerät mit integrierter Herausziehversuchseinrichtung vorgestellt, welches die Durchführung von vielfältigen innovativen Versuchen, mit leicht reproduzierbaren – den in‐situ‐Verhältnissen anpaßbaren – Randbedingungen, dem aktuellen Stand der Versuchstechnik entsprechend und nach den Vorgaben der neuen Normen (z. B. DIN 18137‐3) ermöglicht.